Glossary of fuel cell terms
Encyclopedia
The Glossary of fuel cell terms lists the definitions of many terms used within the fuel cell
industry. The terms in this fuel cell glossary
may be used by fuel cell industry associations, in education material and fuel cell codes and standards to name but a few.
– ACRONYMS
(AAEM) is a semipermeable membrane
generally made from ionomer
s and designed to conduct anions while being impermeable to gases such as oxygen
or hydrogen
.
or hydrogen quality is a term to describe the lack of impurities in hydrogen
as a fuel gas
.
or H2S sensor is a gas sensor for the measurement of hydrogen sulfide
in a gas stream.
(SOEC) is a solid oxide fuel cell set in regenerative mode for the electrolysis of water
with a solid oxide, or ceramic
, electrolyte
to produce oxygen and hydrogen gas.
is a plastic
that melts
to a liquid when heated and freezes to a brittle
, very glass
y state when cooled sufficiently.
allows switching from a primary power source to a secondary or tertiary power source and are employed in some electrical power distribution systems.
(URFC) is a fuel cell
based on the proton exchange membrane
which can do the electrolysis of water
in regenerative mode and function in the other mode as a fuel cell recombining oxygen and hydrogen gas to produce electricity.
Fuel cell
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
industry. The terms in this fuel cell glossary
Glossary
A glossary, also known as an idioticon, vocabulary, or clavis, is an alphabetical list of terms in a particular domain of knowledge with the definitions for those terms...
may be used by fuel cell industry associations, in education material and fuel cell codes and standards to name but a few.
– ACRONYMS
Adsorption
- AdsorptionAdsorptionAdsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
is a process that occurs when a gas or liquid soluteSolutionIn chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
accumulates on the surface of a solid or a liquid (adsorbent), forming a film of molecules or atoms (the adsorbate).
Alkali
- In chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, an alkaliAlkaliIn chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
is a basicBase (chemistry)For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...
, ionicIonic compoundIn chemistry, an ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. Usually, the positively charged portion consists of metal cations and the negatively charged portion is an anion or polyatomic ion. Ions in ionic compounds are held together...
salt of an alkali metalAlkali metalThe alkali metals are a series of chemical elements in the periodic table. In the modern IUPAC nomenclature, the alkali metals comprise the group 1 elements, along with hydrogen. The alkali metals are lithium , sodium , potassium , rubidium , caesium , and francium...
or alkaline earth metalAlkaline earth metalThe alkaline earth metals are a group in the periodic table. In the modern IUPAC nomenclature, the alkaline earth metals are called the group 2 elements. Previously, they were called the Group IIA elements . The alkaline earth metals contain beryllium , magnesium , calcium , strontium , barium and...
elementChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
.
Alkali anion exchange membrane
An alkali anion exchange membraneAlkali anion exchange membrane
An alkali anion exchange membrane is a semipermeable membrane generally made from ionomers and designed to conduct anions while being impermeable to gases such as oxygen or hydrogen...
(AAEM) is a semipermeable membrane
Semipermeable membrane
A semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion".The rate of...
generally made from ionomer
Ionomer
An ionomer is a polymer that comprises repeat units of both electrically neutral repeating units and a fraction of ionized units...
s and designed to conduct anions while being impermeable to gases such as oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
or hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
.
Alkaline fuel cell
- Alkaline fuel cellAlkaline fuel cellThe alkaline fuel cell , also known as the Bacon fuel cell after its British inventor, is one of the most developed fuel cell technologies. NASA has used alkaline fuel cells since the mid-1960s, in Apollo-series missions and on the Space Shuttle. AFCs consume hydrogen and pure oxygen producing...
(AFC) also known as the BaconFrancis Thomas BaconFrancis Thomas Bacon OBE FREng F.R.S. was an English engineer who developed the first practical hydrogen–oxygen fuel cell.- Life and works :...
fuel cell.
Alloy
- An alloyAlloyAn alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
is a solid solutionSolid solutionA solid solution is a solid-state solution of one or more solutes in a solvent. Such a mixture is considered a solution rather than a compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the mixture remains in a single homogeneous phase...
or homogeneousHomogeneous (chemistry)A substance that is uniform in composition is a definition of homogeneous. This is in contrast to a substance that is heterogeneous.The definition of homogeneous strongly depends on the context used. In Chemistry, a homogeneous suspension of material means that when dividing the volume in half, the...
mixture of two or more elementsChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
, at least one of which is a metalMetalA metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
, which itself has metallic properties.
Alternator
- An alternatorAlternatorAn alternator is an electromechanical device that converts mechanical energy to electrical energy in the form of alternating current.Most alternators use a rotating magnetic field but linear alternators are occasionally used...
is an electromechanical device that converts mechanical energy to alternating currentAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
electrical energy.
Alternating current
- An alternating currentAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
(AC) is an electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
whose direction reverses cyclically, as opposed to direct currentDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
, whose direction remains constant.
Ambient temperature
- Ambient temperature is a common term to denote a certain temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
within enclosed space.
Ampere
- The ampereAmpereThe ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...
, in practice often shortened to amp, (symbol: A) is a unit of electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
, or amount of electric chargeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
per second.
Anode
- An anodeAnodeAn anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....
is an electrodeElectrodeAn electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
through which electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
flows into a polarized electrical device.
Aqueous phase reforming
- APR is the production of hydrogen from biomass-derived oxygenated compounds (such as glycerol, sugars and sugar alcohols).
Artificial membrane
- An artificial membraneArtificial membraneAn artificial membrane, or synthetic membrane, is a synthetically created membrane which is usually intended for separation purposes in laboratory or in industry. Synthetic membranes have been successfully used for small and large-scale industrial processes since the middle of twentieth century. A...
, also called a synthetic membrane, is a membrane prepared for separation tasks in laboratoryLaboratoryA laboratory is a facility that provides controlled conditions in which scientific research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories...
and industry.
Atmospheric pressure
- Atmospheric pressureAtmospheric pressureAtmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
is the pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
at any given point in the Earth's atmosphereEarth's atmosphereThe atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
.
Atom
- The atomAtomThe atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
is the smallest unit of an elementChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
that retains the chemical properties of that element. An atom has an electron cloud consisting of negatively chargedElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
electrons surrounding a dense nucleusAtomic nucleusThe nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...
. The nucleus contains positively charged protonProtonThe proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
s and electrically neutral neutronNeutronThe neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
s.
Autothermal reforming
- Autothermal reforming (ATR) uses oxygen and carbon dioxide or steam in a reaction with methane to form syngasSyngasSyngas is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, and in some types of waste-to-energy...
.
Auxiliary power unit
- An auxiliary power unitAuxiliary power unitAn auxiliary power unit is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft, as well as some large land vehicles.-Function:...
(APU) is a device on a vehicle whose purpose is to provide energy for functions other than propulsion.
Availability factor
- The availability factorAvailability factorThe availability factor of a power plant is the amount of time that it is able to produce electricity over a certain period, divided by the amount of the time in the period. Occasions where only partial capacity is available may or may not be deducted...
of a power plant is the amount of time that it is able to produce electricity over a certain period, divided by the amount of the time in the period.
Back pressure
- Back pressureBack pressureBack pressure refers to the resistance to a moving fluid by obstructions or tight bends in the confinement vessel along which it is moving, such as piping or air vents, against its direction of flow....
usually refers to the pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
exerted on a moving fluidFluidIn physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
by obstructions or tight bends in the confinement vessel along which it is moving, such as piping or air vents, against its direction of flow.
Battery
- In electronics, a batteryBattery (electricity)An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
is a combination of two or more electrochemical cellElectrochemical cellAn electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...
s which store chemical energy and make it available as electrical energy.
Biofuel
- BiofuelBiofuelBiofuel is a type of fuel whose energy is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases...
is defined as solid, liquid or gas fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
derived from recently dead biological materialBiomassBiomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
and is distinguished from fossil fuelFossil fuelFossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
s, which are derived from long dead biological material.
Biogas
- BiogasBiogasBiogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Organic waste such as dead plant and animal material, animal dung, and kitchen waste can be converted into a gaseous fuel called biogas...
typically refers to a gas produced by the biological breakdown of organic matterOrganic matterOrganic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...
in the absence of oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. Biogas originates from biogenic material and is a type of biofuelBiofuelBiofuel is a type of fuel whose energy is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases...
.
Bioreactor
- A bioreactor may refer to any device or system that supports a biologically active environment
Biosensor
- A biosensorBiosensorA biosensor is an analytical device for the detection of an analyte that combines a biological component with a physicochemical detector component.It consists of 3 parts:* the sensitive biological element A biosensor is an analytical device for the detection of an analyte that combines a biological...
is a device for the detection of an analyteAnalyteAn analyte, or component , is a substance or chemical constituent that is of interest in an analytical procedure. Grammatically, it is important to note that experiments always seek to measure properties of analytes—and that analytes themselves can never be measured. For instance, one cannot...
that combines a biological component with a physicochemical detector component.
Bipolar plate
- Bipolar plate, conductive plate in a fuel cell stack that acts as an anodeAnodeAn anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....
for one cell and a cathodeCathodeA cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...
for the adjacent cell. The plate may be made of metal or a conductive polymerConductive polymerConductive polymers or, more precisely, intrinsically conducting polymers are organic polymers that conduct electricity. Such compounds may have metallic conductivity or can be semiconductors. The biggest advantage of conductive polymers is their processability, mainly by dispersion. Conductive...
(which may be a carbonCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
-filled composite). The plate usually incorporates flow channels for the fluid feeds and may also contain conduits for heat transfer. See also MEAMembrane electrode assemblyA membrane electrode assembly is an assembled stack of proton exchange membranes or alkali anion exchange membrane , catalyst and flat plate electrode used in a fuel cell.-PEM-MEA:...
.
Black start
- A black startBlack startA black start is the process of restoring a power station to operation without relying on the external electric power transmission network.Normally, the electric power used within the plant is provided from the station's own generators...
is the process of restoring a power stationPower stationA power station is an industrial facility for the generation of electric energy....
to operation without relying on external energy sources.
Beta-alumina solid electrolyte
- Beta-alumina solid electrolyteBeta-alumina solid electrolyteBeta-alumina solid electrolyte is a fast ion conductor material used as a membrane in several types of molten salt electrochemical cell...
(BASE) is a fast ion conductorFast ion conductorIn solid-state ionics, fast ion conductors, also known as solid electrolytes and superionic conductors, are materials that act as solid state ion conductors and are used primarily in solid oxide fuel cells. As solid electrolytes they conduct due to the movement of ions through voids, or empty...
material used as a membraneSemipermeable membraneA semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion".The rate of...
in several types of molten salt electrochemical cellElectrochemical cellAn electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...
.
Boiling point
- The boiling pointBoiling pointThe boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
of a liquid is the water temperature at which the vapor pressureVapor pressureVapor pressure or equilibrium vapor pressure is the pressure of a vapor in thermodynamic equilibrium with its condensed phases in a closed system. All liquids have a tendency to evaporate, and some solids can sublimate into a gaseous form...
of the liquid equals the environmental pressure surrounding the liquid.
Borax
- BoraxBoraxBorax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. It is usually a white powder consisting of soft colorless crystals that dissolve easily in water.Borax has a wide variety of uses...
, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boronBoronBoron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...
compound, a mineralMineralA mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
, and a salt of boric acidBoric acidBoric acid, also called hydrogen borate or boracic acid or orthoboric acid or acidum boricum, is a weak acid of boron often used as an antiseptic, insecticide, flame retardant, as a neutron absorber, and as a precursor of other chemical compounds. It exists in the form of colorless crystals or a...
.
British thermal unit
- The mean British thermal unitBritish thermal unitThe British thermal unit is a traditional unit of energy equal to about 1055 joules. It is approximately the amount of energy needed to heat of water, which is exactly one tenth of a UK gallon or about 0.1198 US gallons, from 39°F to 40°F...
(BTU) is 1/180 of the heat required to raise the temperature of one pound (454 g) of waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
from 32°F to 212°F (0°C to 100°C) at a constant atmospheric pressureAtmospheric pressureAtmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
. It is about equal to the quantity of heat required to raise one pound of water 1°F (°C).
Busbar
- A busbarBusbarIn electrical power distribution, a bus bar is a strip of copper or aluminium that conducts electricity within a switchboard, distribution board, substation or other electrical apparatus....
in electrical power distribution refers to thick strips of copperCopperCopper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
or aluminiumAluminiumAluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
that conduct electricity within a switchboardElectric switchboardAn electric switchboard is a device that directs electricity from one source to another. It is an assembly of panels, each of which contains switches that allow electricity to be redirected. The U.S...
, fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
, distribution boardDistribution boardA distribution board is a component of an electricity supply system which divides an electrical power feed into subsidiary circuits, while providing a protective fuse or circuit breaker for each circuit, in a common enclosure...
, substation, or other electrical apparatus.
Capacity
- Capacity is the ability to hold, receive or absorb, or a measure thereof, similar to the concept of volumeVolumeVolume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
.
Capacity factor
- The net capacity factorCapacity factorThe net capacity factor or load factor of a power plant is the ratio of the actual output of a power plant over a period of time and its potential output if it had operated at full nameplate capacity the entire time...
of a power plant is the ratio of the actual output of a power plant over a period of time and its output if it had operated at full nameplate capacity the entire time.
Capital cost
- Capital costCapital costCapital costs are costs incurred on the purchase of land, buildings, construction and equipment to be used in the production of goods or the rendering of services, in other words, the total cost needed to bring a project to a commercially operable status. However, capital costs are not limited to...
are costs incurred on the purchase of fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s, buildingBuildingIn architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...
s, constructionConstructionIn the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
and equipment to be used in the use of fuel cells or the rendering of it.
Carbon
- CarbonCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
(C), an atom and primary constituent of hydrocarbon fuels. Carbon is routinely left as a black deposit on engine parts, such as pistons, rings, and valves, by the combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
of fuel.
Carbon black
- Carbon blackCarbon blackCarbon black is a material produced by the incomplete combustion of heavy petroleum products such as FCC tar, coal tar, ethylene cracking tar, and a small amount from vegetable oil. Carbon black is a form of amorphous carbon that has a high surface-area-to-volume ratio, although its...
is a material produced by the incomplete combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
of heavy petroleumPetroleumPetroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
products such as FCC tar, coal tar, ethylene cracking tar, and a small amount from vegetable oil.
Carbon dioxide
- Carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
(chemical formulaChemical formulaA chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
: ) is a chemical compoundChemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
composed of two oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
atomAtomThe atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s covalently bondedCovalent bondA covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
to a single carbonCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
atom.
Carbon dioxide sensor
- A carbon dioxide sensor (CO2) is an instrument for the measurement of carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
gas. The most common principles for CO2 sensors are infrared gas sensors (NDIRNDIRA nondispersive infrared sensor sensor is a simple spectroscopic device often used as gas detector.-Principle:The main components are an infrared source , a sample chamber or light tube, a wavelength filter, and the infrared detector...
) and chemical gas sensors.
Carbon monoxide
- Carbon monoxideCarbon monoxideCarbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
, with the chemical formula CO, is a colorless, odorless, tasteless yet highly toxic gas.
Carbon monoxide detector
- A carbon monoxide detectorCarbon monoxide detectorA carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide gas in order to prevent carbon monoxide poisoning. CO is a colorless and odorless compound produced by incomplete combustion. It is often referred to as the "silent killer" because it is...
is a device that detects the presence of the toxic gas carbon monoxideCarbon monoxideCarbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
(CO), a colorless and odorless compound produced by incomplete combustion and lethal at high levels.
Carbon paper
- Carbon paperCarbon paperCarbon paper is paper coated on one side with a layer of a loosely bound dry ink or pigmented coating, usually bound with wax. It is used for making one or more copies simultaneous with the creation of an original document...
(originally carbonic paper) is paperPaperPaper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
coated on one side with a layer of a loosely bound dry inkInkInk is a liquid or paste that contains pigments and/or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush, or quill...
or pigmented coating, usually bound with waxWaxthumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
.
Carnot cycle
- The Carnot cycleCarnot cycleThe Carnot cycle is a theoretical thermodynamic cycle proposed by Nicolas Léonard Sadi Carnot in 1824 and expanded by Benoit Paul Émile Clapeyron in the 1830s and 40s. It can be shown that it is the most efficient cycle for converting a given amount of thermal energy into work, or conversely,...
is a particular thermodynamic cycleThermodynamic cycleA thermodynamic cycle consists of a series of thermodynamic processes transferring heat and work, while varying pressure, temperature, and other state variables, eventually returning a system to its initial state...
, modeled on the hypothetical Carnot heat engineCarnot heat engineA Carnot heat engine is a hypothetical engine that operates on the reversible Carnot cycle. The basic model for this engine was developed by Nicolas Léonard Sadi Carnot in 1824...
.
Catalysis
- CatalysisCatalysisCatalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....
is the process in which the rateReaction rateThe reaction rate or speed of reaction for a reactant or product in a particular reaction is intuitively defined as how fast or slow a reaction takes place...
of a chemical reactionChemical reactionA chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
is increased by means of a chemical substanceChemical substanceIn chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds. They can be solids, liquids or gases.Chemical substances are...
known as a catalyst.
Catalyst
- A catalyst is a chemical substance that increases the rate of a reaction without being consumed; after the reaction it can potentially be recovered from the reaction mixture chemically unchanged.
Catalyst poisoning
- Catalyst poisoningCatalyst poisoningCatalyst poisoning refers to the effect that a catalyst can be 'poisoned' if it reacts with another compound that bonds chemically to its active surface sites. This effectively reduces the usefulness of the catalyst...
refers to the effect that a catalyst can be 'poisoned' if it reacts with another compoundChemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
that bonds chemically (similar to an inhibitorReaction inhibitorA reaction inhibitor is a substance that decreases the rate of, or prevents, a chemical reaction.-Inhibition of a catalyst:An inhibitor can reduce the effectiveness of a catalyst in a catalysed reaction...
) but does not release, or chemically alters the catalyst.
Catalytic partial oxidation
- In catalytic partial oxidation (CPOX) the use of a catalyst for partial oxidationPartial oxidationPartial oxidation is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell...
reduces the required temperature to around 800°C – 900°C. The choice of reformingCatalytic reformingCatalytic reforming is a chemical process used to convert petroleum refinery naphthas, typically having low octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline...
technique depends on the sulfurSulfurSulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
content of the fuel being used. CPOX can be employed if the sulfur content is below 50 ppm. A higher sulfur content would poison the catalyst, so the TPOX procedure is used for such fuels.
Cathode
- A cathodeCathodeA cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...
is an electrodeElectrodeAn electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
through which (positive) electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
flows out of a polarized electrical device.
Celsius
- The degree CelsiusCelsiusCelsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
(°C) can refer to a specific temperature on the Celsius scale as well as serve as a unit increment to indicate a temperature intervalInterval (mathematics)In mathematics, a interval is a set of real numbers with the property that any number that lies between two numbers in the set is also included in the set. For example, the set of all numbers satisfying is an interval which contains and , as well as all numbers between them...
(a difference between two temperatures or an uncertaintyUncertaintyUncertainty is a term used in subtly different ways in a number of fields, including physics, philosophy, statistics, economics, finance, insurance, psychology, sociology, engineering, and information science...
).
Centimeter
- A centimetreCentimetreA centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...
(American spellingAmerican EnglishAmerican English is a set of dialects of the English language used mostly in the United States. Approximately two-thirds of the world's native speakers of English live in the United States....
: centimeter, symbol cm) is a unitUnits of measurementA unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of...
of lengthLengthIn geometric measurements, length most commonly refers to the longest dimension of an object.In certain contexts, the term "length" is reserved for a certain dimension of an object along which the length is measured. For example it is possible to cut a length of a wire which is shorter than wire...
in the metric systemMetric systemThe metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...
, equal to one hundredth of a metreMetreThe metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
, which is the current SIInternational System of UnitsThe International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...
base unitSI base unitThe International System of Units defines seven units of measure as a basic set from which all other SI units are derived. These SI base units and their physical quantities are:* metre for length...
of length.
Centrifugal governor
- A centrifugal governorCentrifugal governorA centrifugal governor is a specific type of governor that controls the speed of an engine by regulating the amount of fuel admitted, so as to maintain a near constant speed whatever the load or fuel supply conditions...
is a specific type of governorGovernor (device)A governor, or speed limiter, is a device used to measure and regulate the speed of a machine, such as an engine. A classic example is the centrifugal governor, also known as the Watt or fly-ball governor, which uses a rotating assembly of weights mounted on arms to determine how fast the engine...
that controls the speedSpeedIn kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...
by regulating the amount of fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
(or working fluidWorking fluidA working fluid is a pressurized gas or liquid that actuates a machine. Examples include steam in a steam engine, air in a hot air engine and hydraulic fluid in a hydraulic motor or hydraulic cylinder...
) admitted, so as to maintain a near constant speed whatever the loadStructural loadStructural loads or actions are forces, deformations or accelerations applied to a structure or its components.Loads cause stresses, deformations and displacements in structures. Assessment of their effects is carried out by the methods of structural analysis...
or fuel supply conditions.
Ceramic
- The word ceramicCeramicA ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
is derived from the GreekGreek languageGreek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
word κεραμικός (keramikos). The term covers inorganic non-metallic materials which are formed by the action of heat.
Cermet
- A cermetCermetA cermet is a composite material composed of ceramic and metallic materials. A cermet is ideally designed to have the optimal properties of both a ceramic, such as high temperature resistance and hardness, and those of a metal, such as the ability to undergo plastic deformation. The metal is used...
is a composite materialComposite materialComposite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
composed of ceramicCeramicA ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
(cer) and metalMetalA metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
lic (met) materials.
Chemical thermodynamics
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, chemical thermodynamicsChemical thermodynamicsChemical thermodynamics is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics...
is the mathematical study of the interrelation of heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
and work with chemical reactions or with a physical change of stateThermodynamic stateA thermodynamic state is a set of values of properties of a thermodynamic system that must be specified to reproduce the system. The individual parameters are known as state variables, state parameters or thermodynamic variables. Once a sufficient set of thermodynamic variables have been...
within the confines of the laws of thermodynamicsLaws of thermodynamicsThe four laws of thermodynamics summarize its most important facts. They define fundamental physical quantities, such as temperature, energy, and entropy, in order to describe thermodynamic systems. They also describe the transfer of energy as heat and work in thermodynamic processes...
.
Circuit
- An circuitElectronic circuitAn electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
is a closed path formed by the interconnection of electronic components through which an electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
can flow.
Circuit diagram
- A circuit diagramCircuit diagramA circuit diagram is a simplified conventional graphical representation of an electrical circuit...
(also known as an electrical diagram, wiring diagramWiring diagramA wiring diagram is a simplified conventional pictorial representation of an electrical circuit. It shows the components of the circuit as simplified shapes, and the power and signal connections between the devices. A wiring diagram usually gives more information about the relative position and...
, elementary diagram, or electronic schematicSchematicA schematic diagram represents the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the information the schematic is intended to convey, and may add unrealistic elements that aid comprehension...
) is a simplified conventional pictorial representation of an electrical circuit.
Circulation
- In fluid dynamicsFluid dynamicsIn physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
, circulation is the line integralLine integralIn mathematics, a line integral is an integral where the function to be integrated is evaluated along a curve.The function to be integrated may be a scalar field or a vector field...
around a closed curve of the fluidFluidIn physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
velocityVelocityIn physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
.
Climate change
- Climate changeClimate changeClimate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
is any long-term significant change in the “average weather” that a given region experiences.
Cogeneration
- CogenerationCogenerationCogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
(also combined heat and power, CHP) is the use of a heat engineHeat engineIn thermodynamics, a heat engine is a system that performs the conversion of heat or thermal energy to mechanical work. It does this by bringing a working substance from a high temperature state to a lower temperature state. A heat "source" generates thermal energy that brings the working substance...
or a power stationPower stationA power station is an industrial facility for the generation of electric energy....
to simultaneously generate both electricity and useful heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
.
Combustion
- CombustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
or burning is a complex sequence of exothermicExothermicIn thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...
chemical reactions between a fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
and an oxidant accompanied by the production of heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
or both heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
and lightLightLight or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
in the form of either a glow or flameFlameA flame is the visible , gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone...
s.
Combustion chamber
- A combustion chamberCombustion chamberA combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...
is the part of an engineEngineAn engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
in which fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
is burned.
Composite material
- Composite materials (or composites for short) are engineered materialMaterialMaterial is anything made of matter, constituted of one or more substances. Wood, cement, hydrogen, air and water are all examples of materials. Sometimes the term "material" is used more narrowly to refer to substances or components with certain physical properties that are used as inputs to...
s made from two or more constituent materials with significantly different physical or chemical properties and which remain separate and distinct on a macroscopic level within the finished structure.
Compressed hydrogen
- Compressed hydrogenCompressed hydrogenCompressed hydrogen is the gaseous state of the element hydrogen kept under pressure. Compressed hydrogen in hydrogen tanks at 350 bar and 700 bar is used for mobile hydrogen storage in hydrogen vehicles...
(CGH2, CH2 or CH2) is the gaseous state of the element hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
which is kept under pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
.
Compressed natural gas
- Compressed Natural GasCompressed natural gasCompressed natural gas is a fossil fuel substitute for gasoline , diesel, or propane/LPG. Although its combustion does produce greenhouse gases, it is a more environmentally clean alternative to those fuels, and it is much safer than other fuels in the event of a spill...
(CNG) is a fossil fuelFossil fuelFossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
substitute for gasolineGasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
(petrol), diesel, or propanePropanePropane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
.
Concentration
- In chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, concentrationConcentrationIn chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...
is the measure of how much of a given substanceChemical substanceIn chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds. They can be solids, liquids or gases.Chemical substances are...
there is mixed with other substances.
Condensate
- Condensate, the liquid phase produced by the condensationCondensationCondensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
of steamSteamSteam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
or any other gas
Condensation
- CondensationCondensationCondensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
is the change of the physical state of aggregation (or simply state) of matter from gaseous phase into liquid phase.
Condenser
- In systems involving heat transferHeat transferHeat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
, a condenserCondenser (heat transfer)In systems involving heat transfer, a condenser is a device or unit used to condense a substance from its gaseous to its liquid state, typically by cooling it. In so doing, the latent heat is given up by the substance, and will transfer to the condenser coolant...
is a heat exchangerHeat exchangerA heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact...
which condensesCondensationCondensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
a substance from its gaseous to its liquid state.
Contamination
- ContaminationContaminationContamination is the presence of a minor and unwanted constituent in material, physical body, natural environment, at a workplace, etc.-Specifics:"Contamination" also has more specific meanings in science:...
is the introduction of material that "does not belong there".
Countercurrent exchange
- Countercurrent exchangeCountercurrent exchangeCountercurrent exchange is a mechanism occurring in nature and mimicked in industry and engineering, in which there is a crossover of some property, usually heat or some component, between two flowing bodies flowing in opposite directions to each other. The flowing bodies can be liquids, gases, or...
is a mechanism used to transfer some property of a fluidFluidIn physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
from one flowing current of fluid to another across a semipermeable membraneSemipermeable membraneA semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion".The rate of...
, conductive material, or free surface (e.g. a liquid–gas absorption or extraction).
Cryogenic liquefaction
- Cryogenic liquificationLiquificationIn physics, to liquefy means to turn something into the liquid state.-In Geology:In geology, liquefaction refers to the process by which saturated, unconsolidated sediments are transformed into a substance that acts like a liquid.Earthquakes can cause soil liquefaction where loosely packed,...
is the process through which gases such as nitrogen, hydrogen, helium, and natural gas are liquefiedLiquificationIn physics, to liquefy means to turn something into the liquid state.-In Geology:In geology, liquefaction refers to the process by which saturated, unconsolidated sediments are transformed into a substance that acts like a liquid.Earthquakes can cause soil liquefaction where loosely packed,...
under pressure at very low temperatures.
Current collector
- The current collectorCurrent collectorElectric current collectors are used for trolleybuses, trams, electric locomotives or EMUsto lead electrical power from overhead lines or electrical third rails to the electrical equipment of the vehicles....
is a term used to describe the conductive material in a fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
that collects electrons (on the anodeAnodeAn anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....
side) or disburses electrons (on the cathodeCathodeA cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...
side). Current collectors are microporous (to allow for fluid flow through them) and lie in between the catalyst/electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
surfaces and the bipolar plates.
DC to DC converter
- In electronic engineeringElectronic engineeringElectronics engineering, also referred to as electronic engineering, is an engineering discipline where non-linear and active electrical components such as electron tubes, and semiconductor devices, especially transistors, diodes and integrated circuits, are utilized to design electronic...
, a DC to DC converterDC to DC converterA DC-to-DC converter is an electronic circuit which converts a source of direct current from one voltage level to another. It is a class of power converter.- Usage :...
is a circuit which converts a source of direct currentDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
(DC) from one voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
level to another. It is a class of power converter.
Desiccant
- A desiccantDesiccantA desiccant is a hygroscopic substance that induces or sustains a state of dryness in its local vicinity in a moderately well-sealed container....
is a hygroscopic substance that induces or sustains a state of dryness (desiccationDesiccationDesiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately sealed container.-Science:...
) in its local vicinity in a moderately-well sealed container.
Detection limit
- In analytical chemistryAnalytical chemistryAnalytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of...
, the detection limitDetection limitIn analytical chemistry, the detection limit, lower limit of detection, or LOD , is the lowest quantity of a substance that can be distinguished from the absence of that substance within a stated confidence limit...
, lower limit of detection, or LOD (limit of detection), is the lowest quantity of a substance that can be distinguished from the absence of that substance (a blank value) within a stated confidence limitConfidence intervalIn statistics, a confidence interval is a particular kind of interval estimate of a population parameter and is used to indicate the reliability of an estimate. It is an observed interval , in principle different from sample to sample, that frequently includes the parameter of interest, if the...
(generally 1%).
Dew point
- The dew pointDew pointThe dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
(sometimes spelled dewpoint) is the temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
to which a given parcel of air must be cooled, at constant barometric pressure, for water vaporWater vaporWater vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
to condenseCondensationCondensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
into water.
Diffusion
- DiffusionDiffusionMolecular diffusion, often called simply diffusion, is the thermal motion of all particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size of the particles...
is part of transport phenomenaTransport phenomena (engineering & physics)In engineering and physics, the study of transport phenomena concerns the exchange of mass, energy, or momentum between observed and studied engineering systems. This subject is a fundamental component of disciplines involved with fluid mechanics, heat transfer, and mass transfer...
. Diffusion is the movement of molecules from a region of higher concentration to one of lower concentration by random molecular motion.
Direct borohydride fuel cell
- Direct borohydride fuel cellDirect borohydride fuel cellDirect borohydride fuel cells are a subcategory of alkaline fuel cells which are directly fed by sodium borohydride or potassium borohydride as a fuel and either air/oxygen or hydrogen peroxide as the oxidant...
(DBFC) a subcategory of alkaline fuel cellAlkaline fuel cellThe alkaline fuel cell , also known as the Bacon fuel cell after its British inventor, is one of the most developed fuel cell technologies. NASA has used alkaline fuel cells since the mid-1960s, in Apollo-series missions and on the Space Shuttle. AFCs consume hydrogen and pure oxygen producing...
s
Direct carbon fuel cell
- Direct carbon fuel cellDirect carbon fuel cellA Direct Carbon Fuel Cell is a fuel cell that uses a carbon rich material as a fuel. The cell produces energy by combining carbon and oxygen, which releases carbon dioxide as a by-product.The total reaction of the cell is C + O2 → CO2....
(DCFC), a fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
that uses a carbonaceous material as a fuel.
Direct current
- Direct currentDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
(DC) is the unidirectional flow of electric chargeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
.
Direct-ethanol fuel cell
- Direct-ethanol fuel cellDirect-ethanol fuel cellDirect-ethanol fuel cells or DEFCs are a subcategory of Proton-exchange fuel cells where the fuel, ethanol, is fed directly to the fuel cell.-Advantages:...
(DEFC) a subcategory of Proton-exchange fuel cellsProton exchange membrane fuel cellProton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...
where, the fuel, ethanolEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, is not reformed, but fed directly to the fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
.
Direct methanol fuel cell
- Direct methanol fuel cell (DMFC) subcategory of proton-exchange fuel cellsProton exchange membrane fuel cellProton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...
where the methanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
(CH3OH) fuel is not reformed as in the indirect methanol fuel cell, but fed directly to the fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
Dispersion
- Dispersion, in fluid dynamics is dispersive mass transferDispersive mass transferDispersive mass transfer, in fluid dynamics, is the spreading of mass from highly concentrated areas to less concentrated areas. It is one form of mass transfer....
, which is the spreading of mass from areas of high to low concentration
Distributed Generation
- Distributed generationDistributed generationDistributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources....
, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources.
Doping
- In semiconductorSemiconductorA semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
production, dopingDoping (semiconductor)In semiconductor production, doping intentionally introduces impurities into an extremely pure semiconductor for the purpose of modulating its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductors are referred to as extrinsic...
is the process of intentionally introducing impurities into an extremely pure (also referred to as intrinsic) semiconductor in order to change its electrical properties.
Downtime
- DowntimeDowntimeThe term downtime is used to refer to periods when a system is unavailable.Downtime or outage duration refers to a period of time that a system fails to provide or perform its primary function...
or outage refers to a period of time or a percentage of a timespan that a systemSystemSystem is a set of interacting or interdependent components forming an integrated whole....
is unavailable or offline.
Effluent
- EffluentEffluentEffluent is an outflowing of water or gas from a natural body of water, or from a human-made structure.Effluent is defined by the United States Environmental Protection Agency as “wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers...
is an outflowing of water from a natural body of water, or from a man-made structure.
Electrical Balance of Plant
- Electrical Balance of Plant (EBOP) ,the user interfaceUser interfaceThe user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...
panel, control equipment, and converting the fuel cell DCDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
power to ACAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
power.
Electricity
- electricity is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric chargeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
.
Electrical conductivity
- Electrical conductivity or specific conductivity is a measure of a material's ability to conduct an electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
.
Electrical efficiency
- The electrical efficiency of an entity (a deviceMachineA machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
, componentElectronic componentAn electronic component is a basic electronic element and may be available in a discrete form having two or more electrical terminals . These are intended to be connected together, usually by soldering to a printed circuit board, in order to create an electronic circuit with a particular function...
, or systemSystemSystem is a set of interacting or interdependent components forming an integrated whole....
) in electronicsElectronicsElectronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
and electrical engineeringElectrical engineeringElectrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
is defined as useful power output divided by the total electrical power consumed (a fractional expressionExpression (mathematics)In mathematics, an expression is a finite combination of symbols that is well-formed according to rules that depend on the context. Symbols can designate numbers , variables, operations, functions, and other mathematical symbols, as well as punctuation, symbols of grouping, and other syntactic...
), typically denoted by the Greek letter small Eta (η).
Electrical insulation
- An electrical insulator is a material that resists the flow of electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
. It is an object intended to support or separate electrical conductorsElectrical conductorIn physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...
without passing current through itself.
Electrical resistance
- Electrical resistanceElectrical resistanceThe electrical resistance of an electrical element is the opposition to the passage of an electric current through that element; the inverse quantity is electrical conductance, the ease at which an electric current passes. Electrical resistance shares some conceptual parallels with the mechanical...
is a ratio of the degree to which an object opposes an electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
through it, measured in OhmOhmThe ohm is the SI unit of electrical resistance, named after German physicist Georg Simon Ohm.- Definition :The ohm is defined as a resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere,...
s.
Electric circuit
- An electrical circuit is a network that has a closed loop, giving a return path for the current. A network is a connection of two or more components, and may not necessarily be a circuit.
Electric current
- Electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
is the flow (movement) of electric chargeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
. The SISiSi, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...
unit of electric current is the ampereAmpereThe ampere , often shortened to amp, is the SI unit of electric current and is one of the seven SI base units. It is named after André-Marie Ampère , French mathematician and physicist, considered the father of electrodynamics...
.
Electricity generation
- Electricity generationElectricity generationElectricity generation is the process of generating electric energy from other forms of energy.The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday...
is the process of converting non-electrical energy to electricity.
Electric power conversion
- In electrical engineeringElectrical engineeringElectrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
, power conversion has a more specific meaning, namely converting electric powerElectric powerElectric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
from one form to another.
Electrochemistry
- ElectrochemistryElectrochemistryElectrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
is a branch of chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
that studies chemical reactions which take place in a solutionSolutionIn chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
at the interface of an electron conductorElectrical conductorIn physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...
(a metalMetalA metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
or a semiconductorSemiconductorA semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
) and an ionic conductor (the electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
), and which involve electron transfer between the electrode and the electrolyte or species in solution.
Electrochemical cell
- An electrochemical cellElectrochemical cellAn electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...
is a device used for generating an electromotive forceElectromotive forceIn physics, electromotive force, emf , or electromotance refers to voltage generated by a battery or by the magnetic force according to Faraday's Law, which states that a time varying magnetic field will induce an electric current.It is important to note that the electromotive "force" is not a...
(voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
) and current from chemical reactionsElectrochemistryElectrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
.
Electrochemical gas sensor
- Electrochemical gas sensorElectrochemical gas sensorElectrochemical gas sensors are gas detectors that measure the concentration of a target gas by oxidizing or reducing the target gas at an electrode and measuring the resulting current.-Construction:...
s are gas detectors that measure the volume of a target gas by oxidizingRedoxRedox reactions describe all chemical reactions in which atoms have their oxidation state changed....
or reducing the target gas at an electrodeElectrodeAn electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
and measuring the resulting current.
Electrode
- An electrodeElectrodeAn electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
is an electrical conductorElectrical conductorIn physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...
used to make contact with a nonmetallic part of a circuitElectronic circuitAn electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
(e.g. a semiconductorSemiconductorA semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
, an electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
or a vacuumVacuumIn everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
).
Electro-galvanic fuel cell
- Electro-galvanic fuel cellElectro-galvanic fuel cellAn electro-galvanic fuel cell is an electrical device, one form of which is commonly used to measure the concentration of oxygen gas in scuba diving and medical equipment....
(EGFC)an electrical device used to measure the concentration of oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
gas in scuba divingScuba divingScuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
and medical equipment.
Electroosmotic flow
- Electroosmotic flow (or Electro-osmotic flow, often abbreviated EOF) is the motion of liquid induced by an applied potential across a capillary tube or microchannel. Electroosmotic flow is an essential component in chemical separation techniques, notably capillary electrophoresis.
Electroosmotic pump
- An electroosmotic pumpElectroosmotic pumpAn electroosmotic pump , or EO pump, is used for generating flow or pressure by use of an electric field. One application of this is removing liquid flooding water from channels and gas diffusion layers and direct hydration of the proton exchange membrane in the membrane electrode assembly of the...
(EOP), or EO pump, is used for removing liquid flooding waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
from channels and gas diffusionDiffusionMolecular diffusion, often called simply diffusion, is the thermal motion of all particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size of the particles...
layers and direct hydrationHydrationHydration may refer to:* Hydration reaction, a chemical addition reaction where a hydroxyl group and proton are added to a compound* Mineral hydration, an inorganic chemical reaction where water is added to the crystal structure of a mineral...
of the proton exchange membraneProton exchange membraneA proton exchange membrane or polymer electrolyte membrane is a semipermeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen...
in the membrane electrode assemblyMembrane electrode assemblyA membrane electrode assembly is an assembled stack of proton exchange membranes or alkali anion exchange membrane , catalyst and flat plate electrode used in a fuel cell.-PEM-MEA:...
(MEA) of the proton exchange membrane fuel cellProton exchange membrane fuel cellProton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...
Electrolysis
- In chemistry and manufacturing, electrolysisElectrolysisIn chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...
is a method of separating chemically bondedChemical bondA chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction...
elementsChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
and compoundsChemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
by passing an electric currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
through them.
Electrolyte
- An electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
is any substance containing free ionIonAn ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
s that behaves as an electrically conductiveElectrical conductorIn physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...
medium.
Electron
- The electronElectronThe electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
is a fundamental subatomic particleSubatomic particleIn physics or chemistry, subatomic particles are the smaller particles composing nucleons and atoms. There are two types of subatomic particles: elementary particles, which are not made of other particles, and composite particles...
that carries a negative electric chargeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
.
Emission standard
- Emission standards are requirements that set specific limits to the amount of pollutants that can be released into the environment.
Endothermic
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, the word endothermicEndothermicIn thermodynamics, the word endothermic describes a process or reaction in which the system absorbs energy from the surroundings in the form of heat. Its etymology stems from the prefix endo- and the Greek word thermasi,...
"within-heating" describes a process or reaction that absorbs energy in the form of heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
.
Energy
- In physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and other scienceScienceScience is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
s, energy is a scalarScalar (physics)In physics, a scalar is a simple physical quantity that is not changed by coordinate system rotations or translations , or by Lorentz transformations or space-time translations . This is in contrast to a vector...
physical quantityPhysical quantityA physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement.-Definition of a physical quantity:Formally, the International Vocabulary of Metrology, 3rd edition defines quantity as:...
that is a property of objects and systems which is conserved by nature. Energy is often defined as the ability to do workWork (thermodynamics)In thermodynamics, work performed by a system is the energy transferred to another system that is measured by the external generalized mechanical constraints on the system. As such, thermodynamic work is a generalization of the concept of mechanical work in mechanics. Thermodynamic work encompasses...
.
Energy carrier
- An energy carrierEnergy carrierAccording to ISO 13600, an energy carrier is either a substance or a phenomenon that can be used to produce mechanical work or heat or to operate chemical or physical processes....
is a substance or phenomenon that can be used to produce mechanical work or heat or to operate chemical or physical processes (ISO 13600).
Energy storage
- Energy storageEnergy storageEnergy storage is accomplished by devices or physical media that store some form of energy to perform some useful operation at a later time. A device that stores energy is sometimes called an accumulator....
is the storing of some form of energy that can be drawn upon at a later time to perform some useful operation.
Energy conversion efficiency
- Energy conversion efficiencyEnergy conversion efficiencyEnergy conversion efficiency is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The useful output may be electric power, mechanical work, or heat.-Overview:...
is the ratio between the useful output of an energy conversion machine and the input, in energy terms.
Energy density
- Energy densityEnergy densityEnergy density is a term used for the amount of energy stored in a given system or region of space per unit volume. Often only the useful or extractable energy is quantified, which is to say that chemically inaccessible energy such as rest mass energy is ignored...
is the amount of energy stored in a given system or region of space per unit volumeVolumeVolume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
, or per unit massMassMass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
, depending on the context, although the latter is more formally specific energySpecific energySpecific energy is defined as the energy per unit mass. Common metric units are J/kg. It is an intensive property. Contrast this with energy, which is an extensive property. There are two main types of specific energy: potential energy and specific kinetic energy. Others are the gray and sievert,...
Energy transformation
- In physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and engineeringEngineeringEngineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, energy transformation or energy conversion, is any process of transforming one form of energy to another.
Enthalpy
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
and molecular chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, the enthalpyEnthalpyEnthalpy is a measure of the total energy of a thermodynamic system. It includes the internal energy, which is the energy required to create a system, and the amount of energy required to make room for it by displacing its environment and establishing its volume and pressure.Enthalpy is a...
or heat content (denoted as H, h, or rarely as χ) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the "useful" work obtainable from a closedClosed system-In physics:In thermodynamics, a closed system can exchange energy , but not matter, with its surroundings.In contrast, an isolated system cannot exchange any of heat, work, or matter with the surroundings, while an open system can exchange all of heat, work and matter.For a simple system, with...
thermodynamic systemThermodynamic systemA thermodynamic system is a precisely defined macroscopic region of the universe, often called a physical system, that is studied using the principles of thermodynamics....
under constant pressure and entropyEntropyEntropy is a thermodynamic property that can be used to determine the energy available for useful work in a thermodynamic process, such as in energy conversion devices, engines, or machines. Such devices can only be driven by convertible energy, and have a theoretical maximum efficiency when...
.
Enthalpy of vaporization
- The enthalpy of vaporization, (symbol
), also known as the heat of vaporization or heat of evaporation, is the energy required to transform a given quantity of a substance into an gas.
Ethanol
- EthanolEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, also called ethyl alcohol, grain alcohol, or drinking alcohol, is a volatileVolatility (chemistry)In chemistry and physics, volatility is the tendency of a substance to vaporize. Volatility is directly related to a substance's vapor pressure. At a given temperature, a substance with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure.The term is primarily...
, flammable, colorless liquid.
Evaporation
- EvaporationEvaporationEvaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
is the process by which moleculeMoleculeA molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
s in a liquid state (e.g. waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
) spontaneously become gaseous (e.g. water vaporWater vaporWater vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
).
Exergy
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, the exergyExergyIn thermodynamics, the exergy of a system is the maximum useful work possible during a process that brings the system into equilibrium with a heat reservoir. When the surroundings are the reservoir, exergy is the potential of a system to cause a change as it achieves equilibrium with its...
of a system is the maximum workMechanical workIn physics, work is a scalar quantity that can be described as the product of a force times the distance through which it acts, and it is called the work of the force. Only the component of a force in the direction of the movement of its point of application does work...
possible during a process that brings the system into equilibriumThermodynamic equilibriumIn thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, radiative equilibrium, and chemical equilibrium. The word equilibrium means a state of balance...
with a heat reservoirHeat reservoirIn thermodynamics, a heat reservoir, thermal reservoir, or heat bath is a system whose heat capacity is so large that when it is in thermal contact with some other system of interest its temperature remains effectively constant. The heat bath is effectively an infinite reservoir of energy and...
.
Exergy efficiency
- Exergy efficiencyExergy efficiencyExergy efficiency computes the efficiency of a process taking the second law of thermodynamics into account.-Motivation:...
(also known as the second-law efficiency or rational efficiency) computes the efficiency of a process taking the second law of thermodynamics into account.
Exhaust gas
- Exhaust gasExhaust gasExhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline/petrol, diesel fuel, fuel oil or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack or propelling nozzle.It often disperses...
is flue gasFlue gasFlue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants...
which occurs as a result of the combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
of fuels such as natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
, gasolineGasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
/petrol, diesel, fuel oilFuel oilFuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...
or coalCoalCoal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
. It is discharged into the atmosphere through an exhaust pipe or flue gas stackFlue gas stackA flue-gas stack is a type of chimney, a vertical pipe, channel or similar structure through which combustion product gases called flue gases are exhausted to the outside air. Flue gases are produced when coal, oil, natural gas, wood or any other fuel is combusted in an industrial furnace, a power...
.
Exothermic
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, the word exothermicExothermicIn thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...
"outside heating" describes a process or reaction that releases energy usually in the form of heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
, but it can also release energy in form of light (e.g. explosions), sound, or electricity (e.g. a battery).
Expansion ratio
- Expansion ratioExpansion ratioThe expansion ratio of a liquefied and cryogenic substance is the volume of a given amount of that substance in liquid form compared to the volume of the same amount of substance in gaseous form, at a given temperature and pressure....
is used in the context of liquefied and cryogenic substances. The expansion ratio of a substance is the volume of a given amount of that substance in liquid form compared to the volume of the same amount of substance in gaseous form, at a given temperature.
Fan
- A mechanical fanFan (mechanical)A mechanical fan is a machine used to create flow within a fluid, typically a gas such as air.A fan consists of a rotating arrangement of vanes or blades which act on the air. Usually, it is contained within some form of housing or case. This may direct the airflow or increase safety by preventing...
is an electrically powered device used to produce an airflow for the purpose of creature comfort (particularly in the heat), ventilationVentilation (architecture)Ventilating is the process of "changing" or replacing air in any space to provide high indoor air quality...
, exhaust, or any other gaseous transport.
Fahrenheit
- FahrenheitFahrenheitFahrenheit is the temperature scale proposed in 1724 by, and named after, the German physicist Daniel Gabriel Fahrenheit . Within this scale, the freezing of water into ice is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees...
is a temperature scaleTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
.In this scale, the freezing point of waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
is 32 degrees Fahrenheit (°F) and the boiling pointBoiling pointThe boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
212 °F
Failure mode and effects analysis
- A failure mode and effects analysisFailure mode and effects analysisA failure modes and effects analysis is a procedure in product development and operations management for analysis of potential failure modes within a system for classification by the severity and likelihood of the failures...
(FMEA) is a procedureProcedure (term)A procedure is a sequence of actions or operations which have to be executed in the same manner in order to always obtain the same result under the same circumstances ....
for analysis of potential failure modes within a system for classification by severity or determination of the effect of failures on the system.
Feedstock purification
- Feedstock purification, The process of removing poisons like sulfurSulfurSulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
(S) and chlorideChlorideThe chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
(Cl) from the feedstock.
Flammability
- FlammabilityFlammabilityFlammability is defined as how easily something will burn or ignite, causing fire or combustion. The degree of difficulty required to cause the combustion of a substance is quantified through fire testing. Internationally, a variety of test protocols exist to quantify flammability...
is the ease with which a substance will ignite, causing fireFireFire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
or combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
.
Flammability limit
- Flammability limits, also called flammable limits, give the proportion of combustibleFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
gases in a mixture, between which limits this mixture is flammableFlammabilityFlammability is defined as how easily something will burn or ignite, causing fire or combustion. The degree of difficulty required to cause the combustion of a substance is quantified through fire testing. Internationally, a variety of test protocols exist to quantify flammability...
.
Flash point
- The flash pointFlash pointThe flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source...
of a flammable liquid is the lowest temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
at which it can form an ignitable mixture in air.
Float valve
- A float valve is a mechanical feedbackFeedbackFeedback describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or...
mechanism that regulates fluid level by using a float to drive an inlet valve so that a higher fluid level will force the valve closed while a lower fluid level will force the valve open.
Flow battery
- Flow batteryFlow batteryA flow battery is a form of rechargeable battery in which electrolyte containing one or more dissolved electroactive species flows through an electrochemical cell that converts chemical energy directly to electricity...
(FB) a form of rechargeable batteryRechargeable batteryA rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to...
in which electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
containing one or more dissolved electroactive species flows through a power cell / reactorElectrochemical cellAn electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...
that converts chemical energyChemical energyChemical energy is the potential of a chemical substance to undergo a transformation through a chemical reaction or, to transform other chemical substances...
to electricity.
Flow measurement
- Flow measurementFlow measurementFlow measurement is the quantification of bulk fluid movement. Flow can be measured in a variety of ways.Positive-displacement flow meters acumulate a fixed volume of fluid and then count the number of times the volume is filled to measure flow...
is the quantification of bulk fluidFluidIn physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
movement. It can be measured in a variety of ways.
Flue gas desulfurization
- Flue gas desulfurizationFlue gas desulfurizationSulfur dioxide is one of the elements forming acid rain. Tall flue-gas stacks disperse emissions by diluting the pollutants in ambient air and transporting them to other regions....
(FGD) is the technology used for removing sulfur dioxideSulfur dioxideSulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
(SO2) from the exhaust flue gasesFlue gas emissions from fossil fuel combustionFlue-gas emissions from fossil-fuel combustion refers to the combustion product gas resulting from the much as 10 to 25 volume percent or more of the flue gas. This is closely followed in volume by water vapor created by the combustion of the hydrogen in the fuel with atmospheric oxygen...
.
Fluid dynamics
- Fluid dynamicsFluid dynamicsIn physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
is the sub-discipline of fluid mechanicsFluid mechanicsFluid mechanics is the study of fluids and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; fluid kinematics, the study of fluids in motion; and fluid dynamics, the study of the effect of forces on fluid motion...
dealing with fluid flow: fluidFluidIn physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
s (liquids and gases) in motion.
Fluid mechanics
- Fluid mechanicsFluid mechanicsFluid mechanics is the study of fluids and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; fluid kinematics, the study of fluids in motion; and fluid dynamics, the study of the effect of forces on fluid motion...
is the study of how fluidFluidIn physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
s move and the forceForceIn physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
s on them. (Fluids include liquids and gases.) Fluid mechanics can be divided into fluid staticsFluid staticsFluid statics is the science of fluids at rest, and is a sub-field within fluid mechanics. The term usually refers to the mathematical treatment of the subject. It embraces the study of the conditions under which fluids are at rest in stable equilibrium...
, the study of fluids at rest, and fluid dynamicsFluid dynamicsIn physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
, the study of fluids in motion.
Flux
- In the study of transport phenomenaTransport phenomena (engineering & physics)In engineering and physics, the study of transport phenomena concerns the exchange of mass, energy, or momentum between observed and studied engineering systems. This subject is a fundamental component of disciplines involved with fluid mechanics, heat transfer, and mass transfer...
(heat transferHeat transferHeat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
, mass transferMass transferMass transfer is the net movement of mass from one location, usually meaning a stream, phase, fraction or component, to another. Mass transfer occurs in many processes, such as absorption, evaporation, adsorption, drying, precipitation, membrane filtration, and distillation. Mass transfer is used...
and fluid dynamicsFluid dynamicsIn physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
), fluxFluxIn the various subfields of physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks.* In the study of transport phenomena , flux is defined as flow per unit area, where flow is the movement of some quantity per time...
is defined as the amount that flows through a unit area per unit time.
Formic acid
- Formic acidFormic acidFormic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...
(systematically called methanoic acid) is the simplest carboxylic acidCarboxylic acidCarboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
. Its formulaFormulaIn mathematics, a formula is an entity constructed using the symbols and formation rules of a given logical language....
is HHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
CCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
OOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
OH or CH2O2.
Formic acid fuel cell
- Formic acid fuel cellFormic acid fuel cellDirect-formic acid fuel cells or DFAFCs are a subcategory of proton exchange membrane fuel cells where, the fuel, formic acid, is not reformed, but fed directly to the fuel cell...
(DFAFC), a subcategory of proton-exchange fuel cells where, the fuel, formic acid, is not reformed, but fed directly to the fuel cell.
Fossil fuel
- Fossil fuels or mineral fuels are fossil source fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
s, that is, hydrocarbons found within the top layer of the Earth’s crustCrust (geology)In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...
.
Frequency changer
- A frequency changerFrequency changerA frequency changer or frequency converter is an electronic device that converts alternating current of one frequency to alternating current of another frequency. The device may also change the voltage, but if it does, that is incidental to its principal purpose.Traditionally, these devices were...
or frequency converter is an electronicElectronicsElectronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
device that converts alternating currentAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
(ACAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
) of one frequencyFrequencyFrequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
to alternating currentAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
of another frequency.
Fuel cell poisoning
- The lowering of a fuel cell's efficiency due to impurities in the fuel binding to the catalyst. See catalyst poisoningCatalyst poisoningCatalyst poisoning refers to the effect that a catalyst can be 'poisoned' if it reacts with another compound that bonds chemically to its active surface sites. This effectively reduces the usefulness of the catalyst...
.
Fuel cell vehicle
- A fuel cell vehicleFuel cell vehicleA Fuel cell vehicle or Fuel Cell Electric Vehicle is a type of hydrogen vehicle which uses a fuel cell to produce electricity, powering its on-board electric motor...
is any vehicleVehicleA vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....
that uses a fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
to produce its on-board motive power.
Fuel efficiency
- Fuel efficiencyFuel efficiencyFuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...
, in its basic sense, is the same as thermal efficiencyThermal efficiencyIn thermodynamics, the thermal efficiency is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, a boiler, a furnace, or a refrigerator for example.-Overview:...
, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
into kinetic energyKinetic energyThe kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
or workMechanical workIn physics, work is a scalar quantity that can be described as the product of a force times the distance through which it acts, and it is called the work of the force. Only the component of a force in the direction of the movement of its point of application does work...
.
Fuel processor
- Device used to generate hydrogen from fuels such as natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
, propanePropanePropane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
, gasolineGasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
, methanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
, and ethanolEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, for use in fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s.
Fusible plug
- A fusible plugFusible plugA fusible plug is a threaded metal cylinder usually of bronze, brass or gunmetal, with a tapered hole drilled completely through its length. This hole is sealed with a metal of low melting point that flows away if a pre-determined, high temperature is reached...
is a threaded metal plug, usually made out of bronzeBronzeBronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...
, brassBrassBrass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
, or gunmetalGunmetalGunmetal, also known as yellow brass in the United States, is a type of bronze – an alloy of copper, tin, and zinc. Originally used chiefly for making guns, gunmetal was eventually superseded by steel...
.
Gadolinium doped ceria
- GadoliniumGadoliniumGadolinium is a chemical element with the symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined form. Gadolinium was first detected spectroscopically in 1880 by de Marignac who separated its oxide and is credited with...
dopedDoping (semiconductor)In semiconductor production, doping intentionally introduces impurities into an extremely pure semiconductor for the purpose of modulating its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductors are referred to as extrinsic...
ceriaCerium(IV) oxideCerium oxide, also known as ceric oxide, ceria, cerium oxide or cerium dioxide, is an oxide of the rare earth metal cerium...
(GDC) – (for SOFC)
Gas
- Fuel gasFuel gasFuel gas can refer to any of several gases burned to produce thermal energy.Natural gas is the most common fuel gas, but others include:* Coal gas or Town gas* Syngas* Mond gas* Propane* Butane* Regasified liquified petroleum gas* Wood gas...
, such as natural gas, undiluted liquefied petroleumPetroleumPetroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
gases (vapor phase only), liquefied petroleum gas–air mixtures, or mixtures of these gases.- Liquefied petroleum gases (LPG) as used in this standard, shall mean and include any material which is composed predominantly of any of the following hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
s, or mixtures of them: propane, propylene, butanes (normal butane or isobutane) and butylenes. - LP gas–air miixture – Liquefied petroleum gases distributed at relatively low pressures and normal atmospheric temperatures which have been diluted with air to produce desired heating value and utilization characteristics.
- Natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
– Mixtures of hydrocarbon gases and vapors consisting principally of methaneMethaneMethane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
(CH4) in gaseous form.
- Liquefied petroleum gases (LPG) as used in this standard, shall mean and include any material which is composed predominantly of any of the following hydrocarbon
Gas compressor
- A gas compressorGas compressorA gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume.Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas...
is a mechanical device that increases the pressure of a gas by reducing its volumeVolumeVolume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
.
Gas detector
- A gas detectorGas detectorA gas detector is a device which detects the presence of various gases within an area, usually as part of a safety system. This type of equipment is used to detect a gas leak and interface with a control system so a process can be automatically shut down...
is a device which detects the presence of various gases within an area, usually as part of a system to warn about gases which might be harmful to humans or animals.
Gas diffusion
- Mixing of two gases caused by random molecular motions. Gases diffuse very quickly; liquids diffuse much more slowly, and solids diffuse at very slow (but often measurable) rates. Molecular collisions make diffusion slower in liquids and solids.
Gas diffusion electrode
- Gas diffusion electrodeGas diffusion electrodeGas diffusion electrodes are electrodes with a conjunction of a solid, liquid and gaseous interface, and an electrical conducting catalyst supporting an electrochemical reaction between the liquid and the gaseous phase...
s are electrodes with a conjunction of a solid, liquid and gaseous interface, and an electrical conducting catalyst supporting an electrochemical reaction between the liquid and the gaseous phase.
Gasification
- GasificationGasificationGasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...
is a process that converts carbonaceous materials, such as coalCoalCoal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
, petroleumPetroleumPetroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
, or biomassBiomassBiomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
, into carbon monoxideCarbon monoxideCarbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
and hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
by reacting the raw material at high temperatures with a controlled amount of oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
and/or steamSteamSteam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
.
Gasoline gallon equivalent
- Gasoline gallon equivalent (GGE) or gasoline-equivalent gallon (GEG) is the amount of alternative fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
it takes to equal the energy content of one liquid gallonGallonThe gallon is a measure of volume. Historically it has had many different definitions, but there are three definitions in current use: the imperial gallon which is used in the United Kingdom and semi-officially within Canada, the United States liquid gallon and the lesser used United States dry...
of gasolineGasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
.
Gibbs free energy
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, the Gibbs free energyGibbs free energyIn thermodynamics, the Gibbs free energy is a thermodynamic potential that measures the "useful" or process-initiating work obtainable from a thermodynamic system at a constant temperature and pressure...
(IUPAC recommended name: Gibbs energy or Gibbs function) is a thermodynamic potential which measures the "useful" or process-initiating work obtainable from an isothermal, isobaricIsobaric processAn isobaric process is a thermodynamic process in which the pressure stays constant. The term derives from the Greek isos, , and barus,...
thermodynamic systemThermodynamic systemA thermodynamic system is a precisely defined macroscopic region of the universe, often called a physical system, that is studied using the principles of thermodynamics....
.
Graphite
- The mineralMineralA mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
graphiteGraphiteThe mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...
, as with diamondDiamondIn mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...
and fullereneFullereneA fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and they resemble the balls used in association football. Cylindrical ones are called carbon nanotubes or buckytubes...
, is one of the allotropes of carbonAllotropes of carbonThis is a list of the allotropes of carbon.-Diamond:Diamond is one of the most well known allotropes of carbon. The hardness and high dispersion of light of diamond make it useful for both industrial applications and jewellery. Diamond is the hardest known natural mineral. This makes it an...
.
Greenhouse effect
- Gases in the Earth's atmosphere that contribute to the greenhouse effectGreenhouse effectThe greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface, energy is transferred to the surface and the lower atmosphere...
, effectively absorbing thermal infraredInfraredInfrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
radiation, emitted by the Earth’sEarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
surface
Greenhouse gases
- Warming of the Earth's atmosphere due to greenhous gasGreenhouse gasA greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
es in the atmosphere that allow solar radiation (visible, ultraviolet) to reach the Earth's atmosphere but do not allow the emitted infrared radiation to pass back out of the Earth's atmosphere.
Grid-tied electrical system
- A grid-tied electrical systemGrid-tied electrical systemA grid-tied electrical system, also called tied to grid or grid tie system, is a semi-autonomous electrical generation or grid energy storage system which links to the mains to feed excess capacity back to the local mains electrical grid...
, also called Tied to grid or Grid tie system, is a semi-autonomous electrical generation or grid energy storageGrid energy storageGrid energy storage refers to the methods used to store electricity on a large scale within an electrical power grid. Electrical energy is stored during times when production exceeds consumption and the stores are used at times when consumption exceeds production...
system which links to the mains to feed excess capacity back to the local mainsMains electricityMains is the general-purpose alternating current electric power supply. In the US, electric power is referred to by several names including household power, household electricity, powerline, domestic power, wall power, line power, AC power, city power, street power, and grid power...
electrical grid.
Guard catalyst bed
- A guard catalyst bed is a fixed bed of pellets of the same catalytic material, see fixed bed reactor.
Half-reaction
- A half reaction is either the oxidation or reduction reaction component of a redox reaction.
Heat exchanger
- A heat exchangerHeat exchangerA heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact...
is a device built for efficient heat transferHeat transferHeat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
from one medium to another, whether the media are separated by a solid wall so that they never mix, or the media are in direct contact.
Heat pipe
- A heat pipeHeat pipeA heat pipe or heat pin is a heat-transfer device that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two solid interfaces....
is a heat transfer mechanism that can transport large quantities of heat with a very small difference in temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
between the hotter and colder interfaces.
Heat transfer
- In thermal physicsThermal scienceThermal science is the combined study of thermodynamics, fluid mechanics, heat transfer, and combustion.-Overview:Introductory subjects studied in thermal science generally are focused on thermodynamics...
, heat transferHeat transferHeat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
is the passage of thermal energyThermal energyThermal energy is the part of the total internal energy of a thermodynamic system or sample of matter that results in the system's temperature....
from a hot to a colder body.
Heating value
- The heating value (TOTAL) (ΔHc0) is the energy released as heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
when a compound undergoes complete combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
with oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. (see also Higher heating value (HHV) and Lower heating value) (LHV).
Heat of combustion
- The heat of combustionHeat of combustionThe heat of combustion is the energy released as heat when a compound undergoes complete combustion with oxygen under standard conditions. The chemical reaction is typically a hydrocarbon reacting with oxygen to form carbon dioxide, water and heat...
(ΔHc0) is the energy released as heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
when a compound undergoes complete combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
with oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. The chemical reaction is typically a hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
reacting with oxygen to form carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
and heat.
Higher heating value
- The higher heating value (HHV) (also known as the gross calorific value or gross energy) of a fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
is defined as the amount of heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
released by a specified quantity (initially at 25 °C) once it is combustedCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
and the products have returned to a temperature of 25 °C.
High-temperature shift
- High-temperature shift (HTS), the water gas shift reactionWater gas shift reactionThe water-gas shift reaction is a chemical reaction in which carbon monoxide reacts with water vapor to form carbon dioxide and hydrogen:The water-gas shift reaction is an important industrial reaction. It is often used in conjunction with steam reforming of methane or other hydrocarbons, which is...
at 350 °C (662 °F) in the presence of a metal-based catalyst (nickelNickelNickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
)
Hybrid electric vehicle
- A hybrid electric vehicleHybrid electric vehicleA hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...
(HEV) is a hybrid vehicleHybrid vehicleA hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles , which combine an internal combustion engine and one or more electric motors.-Power:...
which combines a conventional propulsionGround propulsionGround propulsion is a different term than transport, because it refers to solid bodies being propelled. Those bodies may be mounted on vats or using wheels while the latter dominates for standard applications....
system with a rechargeable energy storage systemRechargeable energy storage systemA rechargeable energy storage system or RESS is a system that stores energy for delivery of power and which is rechargeable.Production storage systems use electric rechargeable traction batteries, electric double-layer capacitors or flywheel energy storage.This term of art is used in US legislation...
(RESS) to achieve better fuel economyFuel economy in automobilesFuel usage in automobiles refers to the fuel efficiency relationship between distance traveled by an automobile and the amount of fuel consumed....
than a conventional vehicle.
Hydride
- HydrideHydrideIn chemistry, a hydride is the anion of hydrogen, H−, or, more commonly, a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties. In compounds that are regarded as hydrides, hydrogen is bonded to a more electropositive element or group...
is the name given to the negativeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
ionIonAn ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
of hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, H−.
Hydride ion
- Aside from electrideElectrideAn electride is an ionic compound in which an electron is the anion. The first electrides to be studied in depth were solutions of alkali metals in ammonia. When sodium metal dissolves in ammonia, the result is a blue solution consisting of [Na6]+ and solvated electrons. Such solutions are powerful...
, the hydride ion is the simplest possible anion, consisting of two electronElectronThe electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s and a protonProtonThe proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
. See also hydrogen anionHydrogen anionThe hydrogen anion is a negative hydrogen ion, H−. It is an important constituent of the atmosphere of stars, such as the Sun, where it is the dominant absorber of photons with energies in the range 0.75-4.0 eV, ranging from the infrared into the visible spectrum...
Hydrocarbon
- In organic chemistryOrganic chemistryOrganic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
, a hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
(HC) is an organic compoundOrganic compoundAn organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
consisting entirely of hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
and carbonCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
.
Hydrocarbon dew point
- The hydrocarbon dew pointHydrocarbon dew pointThe hydrocarbon dew point is the temperature at which the hydrocarbon components of any hydrocarbon-rich gas mixture, such as natural gas, will start to condense out of the gaseous phase. It is often also referred to as the HDP or the HCDP. The maximum temperature at which such condensation takes...
(HDP) or (HCDP) is the temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
(at a given pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
) at which the hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
components of any hydrocarbon-rich gas mixture, such as natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
, will start to condenseCondensationCondensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
out of the gaseous phase.
Hydrodesulfurization
- HydrodesulfurizationHydrodesulfurizationHydrodesulfurization is a catalytic chemical process widely used to remove sulfur from natural gas and from refined petroleum products such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils...
(HDS) is a catalytic chemical process widely used to remove sulfurSulfurSulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
(S) from natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
and from refined petroleum productsOil refineryAn oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...
such as gasoline or petrolGasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
, jet fuelJet fuelJet fuel is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is clear to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1 which are produced to a standardized international specification...
, keroseneKeroseneKerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
, diesel fuel, and fuel oilFuel oilFuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...
s.
Hydrogen
- HydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
is the chemical elementChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
with atomic numberAtomic numberIn chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
1. It is represented by the symbolChemical symbolA chemical symbol is a 1- or 2-letter internationally agreed code for a chemical element, usually derived from the name of the element, often in Latin. Only the first letter is capitalised...
H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetalNonmetalNonmetal, or non-metal, is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, every element in the periodic table can be termed either a metal or a nonmetal...
lic, tasteless, highly flammableCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
diatomic gas with the molecular formula H2.
Hydrogen anion
- The hydrogen anionHydrogen anionThe hydrogen anion is a negative hydrogen ion, H−. It is an important constituent of the atmosphere of stars, such as the Sun, where it is the dominant absorber of photons with energies in the range 0.75-4.0 eV, ranging from the infrared into the visible spectrum...
is a negativeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
hydrogen ionHydrogen ionHydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes.Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions....
, H−. See also hydride ion.
Hydrogen purity
Hydrogen purityHydrogen purity
Hydrogen purity or hydrogen quality is a term to describe the lack of impurities in hydrogen as a fuel gas. The purity requirement varies with the application, for example a H2 ICE can tolerate low hydrogen purity where a hydrogen fuel cell requires high hydrogen purity to prevent catalyst...
or hydrogen quality is a term to describe the lack of impurities in hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
as a fuel gas
Fuel gas
Fuel gas can refer to any of several gases burned to produce thermal energy.Natural gas is the most common fuel gas, but others include:* Coal gas or Town gas* Syngas* Mond gas* Propane* Butane* Regasified liquified petroleum gas* Wood gas...
.
Hydrogen-rich fuel
- A fuel that contains a significant amount of hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, such as gasoline, diesel fuel, methanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
(CH3OH), ethanolEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
(CH3CH2OH), natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
, and coal.
Hydrogen sulfide sensor
A hydrogen sulfide sensorHydrogen sulfide sensor
A hydrogen sulfide sensor or H2S sensor is a gas sensor for the measurement of hydrogen sulfide.-Principle:The H2S sensor is a metal oxide semiconductor sensor which operates by a reversible change in resistance caused by adsorption and desorption of hydrogen sulfide in a film with hydrogen...
or H2S sensor is a gas sensor for the measurement of hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
in a gas stream.
Impurity
- Impurities are substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound.
Interlock
- InterlockingInterlock (engineering)Interlocking is a method of preventing undesired states in a state machine, which in a general sense can include any electrical, electronic, or mechanical device or system....
is a method of preventing undesired states in a state machineFinite state machineA finite-state machine or finite-state automaton , or simply a state machine, is a mathematical model used to design computer programs and digital logic circuits. It is conceived as an abstract machine that can be in one of a finite number of states...
, which in a general sense can include any electrical, electronic, or mechanical device or system.
Internal combustion engine
- An internal combustion engineInternal combustion engineThe internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
(ICE) is an engine in which the combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
of fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
and an oxidizer (typically air) occurs in a confined space called a combustion chamberCombustion chamberA combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...
.
Inverter
- An inverterInverter (electrical)An inverter is an electrical device that converts direct current to alternating current ; the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits....
is an electrical or electro-mechanical device that converts direct currentDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
(DC) to alternating currentAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
(AC)
Ion
- An ionIonAn ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
is an atomAtomThe atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
or moleculeMoleculeA molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
which has lost or gained one or more valence electronValence electronIn chemistry, valence electrons are the electrons of an atom that can participate in the formation of chemical bonds with other atoms. Valence electrons are the "own" electrons, present in the free neutral atom, that combine with valence electrons of other atoms to form chemical bonds. In a single...
s, giving it a positive or negative electrical charge.
Ion exchange
- Ion exchangeIon exchangeIon exchange is an exchange of ions between two electrolytes or between an electrolyte solution and a complex. In most cases the term is used to denote the processes of purification, separation, and decontamination of aqueous and other ion-containing solutions with solid polymeric or mineralic 'ion...
is an exchange of ionIonAn ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
s between two electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
s or between an electrolyte solutionSolutionIn chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
and a complexComplex (chemistry)In chemistry, a coordination complex or metal complex, is an atom or ion , bonded to a surrounding array of molecules or anions, that are in turn known as ligands or complexing agents...
.
Ion exchange resin
- An ion exchange resinIon exchange resinAn ion-exchange resin or ion-exchange polymer is an insoluble matrix normally in the form of small beads, usually white or yellowish, fabricated from an organic polymer substrate. The material has highly developed structure of pores on the surface of which are sites with easily trapped and...
is an insoluble matrix (or support structure) normally in the form of small (1–2 mm diameter) beads, usually white or yellowish, fabricated from an organic polymerPolymerA polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
substrate.
Ionomer
- An ionomerIonomerAn ionomer is a polymer that comprises repeat units of both electrically neutral repeating units and a fraction of ionized units...
is a polyelectrolytePolyelectrolytePolyelectrolytes are polymers whose repeating units bear an electrolyte group. These groups will dissociate in aqueous solutions , making the polymers charged. Polyelectrolyte properties are thus similar to both electrolytes and polymers , and are sometimes called polysalts. Like salts, their...
that comprises copolymers containing both electricallyElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
neutral repeating units and a fraction of ionIonAn ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
ized units
Islanding
- IslandingIslandingIslanding refers to the condition in which a distributed generation generator continues to power a location even though electrical grid power from the electric utility is no longer present. Islanding can be dangerous to utility workers, who may not realize that a circuit is still powered, and it...
refers to the condition of a distributed GenerationDistributed generationDistributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources....
(DG) generator continuing to power a location even though power from the electric utilityElectric utilityAn electric utility is a company that engages in the generation, transmission, and distribution of electricity for sale generally in a regulated market. The electrical utility industry is a major provider of energy in most countries. It is indispensable to factories, commercial establishments,...
is no longer present.
Kröger–Vink notation
- Kröger–Vink notation is set of conventions used to describe electrical charge and lattice position for point defectCrystallographic defectCrystalline solids exhibit a periodic crystal structure. The positions of atoms or molecules occur on repeating fixed distances, determined by the unit cell parameters. However, the arrangement of atom or molecules in most crystalline materials is not perfect...
species in crystalsCrystal structureIn mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...
.
Kilogram
- The kilogramKilogramThe kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
or kilogramme (symbol: kg) is the base unitSI base unitThe International System of Units defines seven units of measure as a basic set from which all other SI units are derived. These SI base units and their physical quantities are:* metre for length...
of massMassMass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
in the International System of UnitsInternational System of UnitsThe International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...
(known also by its French-language initials “SI”). The kilogram is defined as being equal to the mass of the International Prototype Kilogram which is almost exactly equal to the mass of one literLitrepic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
of water.
Kilowatt
- The kilowatt (symbol: kW), equal to one thousand watts, is typically used to state the power output of engines and the power consumption of tools and machines.
Kilowatt hour
- The kilowatt hour, also written kilowatt-hour (symbol kW·h, kW h or kWh) is a unit of energy.
Lanthanum carbonate
- Lanthanum carbonateLanthanum carbonateLanthanum carbonate, La23, is the salt formed by lanthanum cations and carbonate anions. It is an ore of lanthanum metal, along with monazite.- Chemistry :...
is used as a lanthanum source for solid-state production of lanthanum strontium manganiteLanthanum strontium manganiteLanthanum strontium manganite is an oxide ceramic material with the general formula La1-xSrxMnO3, where x describes the doping level and is usually in the range of 10-20%....
(LSM), primarily for solid oxide fuel cell applications.
Life cycle assessment
- A life cycle assessmentLife cycle assessmentA life-cycle assessment is a technique to assess environmental impacts associated with all the stages of a product's life from-cradle-to-grave A life-cycle assessment (LCA, also known as life-cycle analysis, ecobalance, and cradle-to-grave analysis) is a technique to assess environmental impacts...
(LCA, also known as life cycle analysis, ecobalance, and cradle-to-grave analysis) is the investigation and valuation of the environmental impactSustainabilitySustainability is the capacity to endure. For humans, sustainability is the long-term maintenance of well being, which has environmental, economic, and social dimensions, and encompasses the concept of union, an interdependent relationship and mutual responsible position with all living and non...
s of a given product or service caused or necessitated by its existence.
Linear regulator
- In electronics, a linear regulatorLinear regulatorIn electronics, a linear regulator is a voltage regulator based on an active device operating in its "linear region" or passive devices like Zener diodes operated in their breakdown region...
is a voltage regulatorVoltage regulatorA voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components...
based on an active device (such as a bipolar junction transistorBipolar junction transistor|- align = "center"| || PNP|- align = "center"| || NPNA bipolar transistor is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons...
, field effect transistor or vacuum tubeVacuum tubeIn electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
) operating in its "linear region"
Liquid hydrogen
- Liquid hydrogenLiquid hydrogenLiquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...
(LH2 or LH2) is the liquid state of the element hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
.
Liquid–liquid extraction
- Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilitiesSolubilitySolubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
in two different immiscible liquids, usually water and an organic solventSolventA solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
.
Liquefied natural gas
- Liquefied natural gasLiquefied natural gasLiquefied natural gas or LNG is natural gas that has been converted temporarily to liquid form for ease of storage or transport....
(LNG) is natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
(primarily methaneMethaneMethane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
, CH4) that has been converted to liquid form for ease of storage or transport.
Liquefied petroleum gas
- Liquefied petroleum gas (also called LPG, GPL, LP Gas, or autogas) is a mixture of hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
gases used as a fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
in heating appliances and vehicles
Liquification
- In physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, to liquefyLiquificationIn physics, to liquefy means to turn something into the liquid state.-In Geology:In geology, liquefaction refers to the process by which saturated, unconsolidated sediments are transformed into a substance that acts like a liquid.Earthquakes can cause soil liquefaction where loosely packed,...
(sometimes misspelt liquify) means to turn something into the liquid state.
Liquefaction of gases
- Liquefaction of gasesLiquefaction of gasesLiquefaction of gases includes a number of phases used to convert a gas into a liquid state. The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require...
includes a number of phases used to convert a gas into a liquid state.
List of chemical purification methods in chemistry
- Purification in a chemical context is the physical separation of a chemical substance of interest from foreign or contaminatingContaminationContamination is the presence of a minor and unwanted constituent in material, physical body, natural environment, at a workplace, etc.-Specifics:"Contamination" also has more specific meanings in science:...
substances. The following list of chemical purification methods should not be considered exhaustive.
Load following power plant
- A load following power plantLoad following power plantA load following power plant is a power plant that adjusts its power output as demand for electricity fluctuates throughout the day. Load following plants are typically in-between base load and peaking power plants in efficiency, speed of startup and shutdown, construction cost, cost of electricity...
is a power plant that adjusts its power output as demand for electricity fluctuates throughout the day.
Load profile
- In electrical engineeringElectrical engineeringElectrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
, a load profileLoad profileIn electrical engineering, a load profile is a graph of the variation in the electrical load versus time. A load profile will vary according to customer type , temperature and holiday seasons....
is a graph of the variation in the electrical load versus time.
Lower flammability limit
- Lower flammability limit (LFL), usually expressed in volume per cent, is the lower end of the concentration range of a flammable solvent at a given temperature and pressure for which air/vapor mixtures can ignite.
Lower heating value
- The lower heating value (also known as net calorific value, net CV, or LHV) of a fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
is defined as the amount of heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
released by combusting a specified quantity (initially at 25 °C or another reference state) and returning the temperature of the combustionCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
products to 150 °C.
Low temperature shift
- Low temperature shift (LTS), the water gas shift reactionWater gas shift reactionThe water-gas shift reaction is a chemical reaction in which carbon monoxide reacts with water vapor to form carbon dioxide and hydrogen:The water-gas shift reaction is an important industrial reaction. It is often used in conjunction with steam reforming of methane or other hydrocarbons, which is...
at 190–210°C (374–410°F) in the presence of a metal-based catalyst (nickelNickelNickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
).
Maintenance, repair and operations
- Maintenance, Repair and OperationsMaintenance, Repair and OperationsMaintenance, repair, and operations or maintenance, repair, and overhaul involves fixing any sort of mechanical or electrical device should it become out of order or broken...
or Maintenance, Repair and Overhaul (MRO) is fixing any sort of mechanicalMachineA machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
or electrical deviceMachineA machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
should it become out of order or broken (repair) as well as performing the routine actions which keep the device in working order (maintenance) or prevent trouble from arising (preventive maintenancePreventive maintenancePreventive maintenance has the following meanings:#The care and servicing by personnel for the purpose of maintaining equipment and facilities in satisfactory operating condition by providing for systematic inspection, detection, and correction of incipient failures either before they occur or...
).
Mass flow sensor
- A mass flow sensorMass flow sensorA mass air flow sensor is used to find out the mass flowrate of air entering a fuel-injected internal combustion engine. The air mass information is necessary for the engine control unit to balance and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts...
(MAF) responds to the amount of a fluid (usually a gas) flowing through a chamber containing the sensorSensorA sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...
.
Maximum allowable operating pressure
- Maximum allowable operating pressureMaximum allowable operating pressureMaximum allowable operating pressure or MAOP refers to the wall strength of a pressurized cylinder such as a pipeline or storage tank and how much pressure the walls may safely hold in normal operation....
(MAOP) refers to the wall strength of a pressurized cylinderPneumatic cylinderPneumatic cylinders are mechanical devices which utilize the power of compressed gas to produce a force in a reciprocating linear motion....
such as a pipelinePipeline transportPipeline transport is the transportation of goods through a pipe. Most commonly, liquids and gases are sent, but pneumatic tubes that transport solid capsules using compressed air are also used....
or storage tankStorage tankA storage tank is a container, usually for holding liquids, sometimes for compressed gases . The term can be used for reservoirs , and for manufactured containers. The usage of the word tank for reservoirs is common or universal in Indian English, American English and moderately common in British...
and how much pressure the walls may safely hold before rupturing.
Mean down time
- In organizationOrganizationAn organization is a social group which distributes tasks for a collective goal. The word itself is derived from the Greek word organon, itself derived from the better-known word ergon - as we know `organ` - and it means a compartment for a particular job.There are a variety of legal types of...
al managementManagementManagement in all business and organizational activities is the act of getting people together to accomplish desired goals and objectives using available resources efficiently and effectively...
, mean down timeMean down timeIn organizational management, mean down time is the average time that a system is non-operational. This includes all time associated with repair, corrective and preventive maintenance, self imposed downtime, and any logistics or administrative delays...
(MDT) is the averageAverageIn mathematics, an average, or central tendency of a data set is a measure of the "middle" value of the data set. Average is one form of central tendency. Not all central tendencies should be considered definitions of average....
time that a system is non-operational.
Mean time between failures
- Mean time between failures (MTBF) is the meanMeanIn statistics, mean has two related meanings:* the arithmetic mean .* the expected value of a random variable, which is also called the population mean....
(average) time between failureFailureFailure refers to the state or condition of not meeting a desirable or intended objective, and may be viewed as the opposite of success. Product failure ranges from failure to sell the product to fracture of the product, in the worst cases leading to personal injury, the province of forensic...
s of a system, and is often attributed to the "useful life" of the device i.e. not including 'infant mortality' or 'end of life' if the device is not repairable.
Mean time between outages
- In a systemSystemSystem is a set of interacting or interdependent components forming an integrated whole....
the mean time between outages (MTBO) is the mean timeTimeTime is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
between equipment failures that result in loss of system continuity or unacceptable degradationDegradation (telecommunications)In telecommunication, degradation, which may be categorized as either "graceful" or "catastrophic", has the following meanings:#The deterioration in quality, level, or standard of performance of a functional unit....
.
Mechanical energy
- In physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, mechanical energyMechanical energyIn physics, mechanical energy is the sum of potential energy and kinetic energy present in the components of a mechanical system. It is the energy associated with the motion and position of an object. The law of conservation of energy states that in an isolated system that is only subject to...
describes the potential energyPotential energyIn physics, potential energy is the energy stored in a body or in a system due to its position in a force field or due to its configuration. The SI unit of measure for energy and work is the Joule...
and kinetic energyKinetic energyThe kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
present in the components of a mechanical system.Does anybody kow how to find it?
Mechanical Balance of Plant
- Mechanical Balance of Plant (MBOP), the process equipment needed to provide steam, gas, and air to the fuel cell stack.
Membrane electrode assembly
- Membrane electrode assemblyMembrane electrode assemblyA membrane electrode assembly is an assembled stack of proton exchange membranes or alkali anion exchange membrane , catalyst and flat plate electrode used in a fuel cell.-PEM-MEA:...
(MEA) is an assembled stack of proton exchange membraneProton exchange membraneA proton exchange membrane or polymer electrolyte membrane is a semipermeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen...
s.
Megawatt
- The megawatt (symbol: MW) is equal to one million (1000000) watts.
Meter
- Meter (m), Basic metric unit of length equal to 3.28 feet, 1.09 yards or 39.37 inches. Related units are the decimeter (dm) at 10 per meter, the centimeter (cm) at 100 per meter, the millimeter (mm) at 1000 per meter and the kilometer (km) at 1000 meters.
Methanation
- MethanationMethanationMethanation is a physical-chemical process to generate Methane from a mixture of various gases out of biomass fermentation or thermo-chemical gasification. The main components are carbon monoxide and hydrogen...
is a physical-chemical process to generate MethaneMethaneMethane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
from a mixture of various gases out of biomass fermentationFermentation (biochemistry)Fermentation is the process of extracting energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound. In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen,...
or thermo-chemical gasificationGasificationGasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...
.
Methane
- MethaneMethaneMethane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
is a chemical compoundChemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the molecular formula . It is the simplest alkaneAlkaneAlkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
, and the principal component of natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
.
Methane reformer
- A methane reformerMethane reformerA methane refomer is a device based on steam reforming or autothermal reforming and is a type of chemical synthesis, which can produce pure hydrogen gas from natural gas using a catalyst. There are two natural gas reformer technologies — autothermal reforming and steam methane reforming...
is a device used in chemical engineeringChemical engineeringChemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...
, which can produce pure hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
gas from natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
using a catalyst. (See ATR and SMRSteam reformingFossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to...
).
Methanol
- MethanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a chemical compoundChemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with chemical formulaChemical formulaA chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
CCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
HHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
3OHHydroxideHydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and a hydrogen atom held together by a covalent bond, and carrying a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, as a ligand, a nucleophile, and a...
(often abbreviated MeOH).
Methanol reformer
- A methanol reformerMethanol reformerA methanol refomer is a device used in chemical engineering, especially in the area of fuel cell technology, which can produce pure hydrogen gas and carbon dioxide by reacting a methanol and water mixture....
is a device used in chemical engineeringChemical engineeringChemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...
, especially in the area of fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
technology, which can produce pure hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
gas and carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
by reacting a methanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
and waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
(steam) mixture.
MicroCHP
- "Micro cogeneration"MicroCHPMicro combined heat and power or micro-CHP is an extension of the now well established idea of cogeneration to the single/multi family home or small office building.- Overview :...
or micro combined heat and power (mCHP) is a so called distributed energy resource (DER).
Microbial fuel cell
- Microbial fuel cellMicrobial fuel cellA microbial fuel cell or biological fuel cell is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature....
(MFC) or biological fuel cell is a bio-electrochemical system that drives a currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
by mimicking bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l interactions found in natureNatureNature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general...
.
Micropump
- A small pump is often referred to as micropumpMicropumpAlthough any kind of small pump is often referred to as micropump, a more accurate and up-to-date definition restricts this term to pumps with functional dimensions in the micrometre range. Such pumps are of special interest in microfluidic research, and have become available for industrial product...
, a more accurate and up-to-date definition restricts this term to pumps with functional dimensions in the micrometre range.
Miles per gallon equivalent
- Miles per gallon of gasoline equivalent (MPGe) is a unit of measurement that relates efficiencies of different systems to the traditional unit of measurement for fuel efficiencyFuel efficiencyFuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...
(miles per gallon of gasoline).
Millimeter
- Millimeter (mm), Metric unit of length, equal to 0.04 inch (there are 25 mm in an inch). There are 1000 millimeters in a meter.
Molten-carbonate fuel cells
- Molten-carbonate fuel cells (MCFCs) are high-temperature fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s
Nano iron powder
- Nano iron powder is an iron powder with granules' sizes ranging on the nanoscale.
Nanowire
- A nanowireNanowireA nanowire is a nanostructure, with the diameter of the order of a nanometer . Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. At these scales, quantum mechanical effects are important —...
is a wire of diameter of the order of a nanometer (10−9 meters).
Natural gas
- Natural gasNatural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
is a gaseous fossil fuelFossil fuelFossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
consisting primarily of methaneMethaneMethane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
but including significant quantities of ethaneEthaneEthane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas....
, propanePropanePropane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
, butaneButaneButane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...
, and pentanePentanePentane is an organic compound with the formula C5H12 — that is, an alkane with five carbon atoms. The term may refer to any of three structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, pentane means exclusively the n-pentane isomer; the other two being called...
—heavier hydrocarbons removed prior to use as a consumer fuel —as well as carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, nitrogenNitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, heliumHeliumHelium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
and hydrogen sulfideHydrogen sulfideHydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
.
Nernst equation
- In electrochemistryElectrochemistryElectrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
, the Nernst equationNernst equationIn electrochemistry, the Nernst equation is an equation that can be used to determine the equilibrium reduction potential of a half-cell in an electrochemical cell. It can also be used to determine the total voltage for a full electrochemical cell...
is an equation which can be used (in conjunction with other information) to determine the equilibrium reduction potentialReduction potentialReduction potential is a measure of the tendency of a chemical species to acquire electrons and thereby be reduced. Reduction potential is measured in volts , or millivolts...
of a half-cell in an electrochemical cellElectrochemical cellAn electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...
.
Net energy gain
- Net energy gainNet energy gainNet Energy Gain is a concept used in energy economics that refers to the difference between the energy expended to harvest an energy source and the amount of energy gained from that harvest. The net energy gain, which can be expressed in joules, differs from the net financial gain that may result...
(NEG) is a concept important in energy economicsEnergy economicsEnergy economics is a broad scientific subject area which includes topics related to supply and use of energy in societies. Due to diversity of issues and methods applied and shared with a number of academic disciplines, energy economics does not present itself as a self contained academic...
, referring to a surplus condition in the difference between the energy required to harvest an energy source and the energy provided by that same source.
Nickel
- NickelNickelNickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
is a metallic chemical elementChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
with the symbol Ni and atomic numberAtomic numberIn chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
28.
Nitrogen
- NitrogenNitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
N2 a chemical elementChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
that has the symbol N and atomic numberAtomic numberIn chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
7 and atomic weightAtomic weightAtomic weight is a dimensionless physical quantity, the ratio of the average mass of atoms of an element to 1/12 of the mass of an atom of carbon-12...
14.0067. Elemental nitrogen is a colorless, odorless, tasteless and mostly inertInert-Chemistry:In chemistry, the term inert is used to describe a substance that is not chemically reactive.The noble gases were previously known as inert gases because of their perceived lack of participation in any chemical reactions...
diatomicDiatomicDiatomic molecules are molecules composed only of two atoms, of either the same or different chemical elements. The prefix di- means two in Greek. Common diatomic molecules are hydrogen , nitrogen , oxygen , and carbon monoxide . Seven elements exist in the diatomic state in the liquid and solid...
gas at standard conditions, constituting 78.08% by volume of Earth's atmosphereEarth's atmosphereThe atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
.
Nitrogen oxide
- The term nitrogen oxideNitrogen oxideNitrogen oxide can refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:* Nitric oxide, also known as nitrogen monoxide, , nitrogen oxide* Nitrogen dioxide , nitrogen oxide...
(NOx) typically refers to any binary compoundBinary compoundA binary compound is a chemical compound that contains exactly two different elements. Examples of binary ionic compounds include calcium chloride , sodium fluoride , and magnesium oxide , whilst examples of binary covalent compounds include water , carbon monoxide , and sulfur hexafluoride...
of oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
and nitrogenNitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, or to a mixture of such compounds
Nitrogen oxide sensor
- A nitrogen oxide sensor or NOx sensor is typically a high temperature device built to detect nitrogen oxideNitrogen oxideNitrogen oxide can refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:* Nitric oxide, also known as nitrogen monoxide, , nitrogen oxide* Nitrogen dioxide , nitrogen oxide...
s in combustion environments such as an automobileAutomobileAn automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
or truck tailpipe or a smokestack.
Off board reforming
- Off board reforming, stationary reforming, see steam reformingSteam reformingFossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to...
, methane reformerMethane reformerA methane refomer is a device based on steam reforming or autothermal reforming and is a type of chemical synthesis, which can produce pure hydrogen gas from natural gas using a catalyst. There are two natural gas reformer technologies — autothermal reforming and steam methane reforming...
, methanol reformerMethanol reformerA methanol refomer is a device used in chemical engineering, especially in the area of fuel cell technology, which can produce pure hydrogen gas and carbon dioxide by reacting a methanol and water mixture....
Ohm
- The ohmOhmThe ohm is the SI unit of electrical resistance, named after German physicist Georg Simon Ohm.- Definition :The ohm is defined as a resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere,...
(symbol: Ω) is the SISiSi, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...
unit of electrical impedanceElectrical impedanceElectrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...
or, in the direct currentDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
case, electrical resistanceElectrical resistanceThe electrical resistance of an electrical element is the opposition to the passage of an electric current through that element; the inverse quantity is electrical conductance, the ease at which an electric current passes. Electrical resistance shares some conceptual parallels with the mechanical...
, named after Georg OhmGeorg OhmGeorg Simon Ohm was a German physicist. As a high school teacher, Ohm began his research with the recently-invented electrochemical cell, invented by Italian Count Alessandro Volta. Using equipment of his own creation, Ohm determined that there is a direct proportionality between the potential...
.
Onboard reforming
- On-board reforming, reforming on board a vehicleVehicleA vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....
, see steam reformingSteam reformingFossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to...
, methane reformerMethane reformerA methane refomer is a device based on steam reforming or autothermal reforming and is a type of chemical synthesis, which can produce pure hydrogen gas from natural gas using a catalyst. There are two natural gas reformer technologies — autothermal reforming and steam methane reforming...
, methanol reformerMethanol reformerA methanol refomer is a device used in chemical engineering, especially in the area of fuel cell technology, which can produce pure hydrogen gas and carbon dioxide by reacting a methanol and water mixture....
Open-circuit voltage
- Open-circuit voltageOpen-circuit voltageOpen-circuit voltage is the difference of electrical potential between two terminals of a device when there is no external load connected, i.e. the circuit is broken or open. Under these conditions there is no external electric current between the terminals, even though there may be current...
or OCV is the difference of electrical potential between two terminals of a device when there is no external loadExternal electric loadIf an electric circuit has a well-defined output terminal, the circuit connected to this terminal is the load....
connected, i.e. the circuitElectrical networkAn electrical network is an interconnection of electrical elements such as resistors, inductors, capacitors, transmission lines, voltage sources, current sources and switches. An electrical circuit is a special type of network, one that has a closed loop giving a return path for the current...
is broken or open.
Original equipment manufacturer
- An original equipment manufacturerOriginal Equipment ManufacturerAn original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...
, or OEM is typically a company that uses a component made by a second company in its own product, or sells the product of the second company under its own brandBrandThe American Marketing Association defines a brand as a "Name, term, design, symbol, or any other feature that identifies one seller's good or service as distinct from those of other sellers."...
.
Output impedance
- Output impedanceOutput impedanceThe output impedance, source impedance, or internal impedance of an electronic device is the opposition exhibited by its output terminals to an alternating current of a particular frequency as a result of resistance, inductance and capacitance...
, Any linear electronic circuit or device which supplies a current may be modelled as an ideal voltage source in series with an impedanceElectrical impedanceElectrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...
. This is helpful in analysing the voltage drop which occurs as current is drawn.
Overpotential
- In electrochemistryElectrochemistryElectrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
, overpotentialOverpotentialOverpotential is an electrochemical term which refers to the potential difference between a half-reaction's thermodynamically determined reduction potential and the potential at which the redox event is experimentally observed. The term is directly related to a cell's voltage efficiency...
is the difference in the electric potentialElectric potentialIn classical electromagnetism, the electric potential at a point within a defined space is equal to the electric potential energy at that location divided by the charge there...
of an electrode with no currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
through it, at equilibriumChemical equilibriumIn a chemical reaction, chemical equilibrium is the state in which the concentrations of the reactants and products have not yet changed with time. It occurs only in reversible reactions, and not in irreversible reactions. Usually, this state results when the forward reaction proceeds at the same...
, and with a current.
Overvoltage
- When the voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
in a circuitElectrical networkAn electrical network is an interconnection of electrical elements such as resistors, inductors, capacitors, transmission lines, voltage sources, current sources and switches. An electrical circuit is a special type of network, one that has a closed loop giving a return path for the current...
or part of it is raised above its upper design limit, this is known as overvoltageOvervoltageWhen the voltage in a circuit or part of it is raised above its upper design limit, this is known as overvoltage. The conditions may be hazardous...
.
Oxidant
- An oxidizing agentOxidizing agentAn oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox chemical reaction...
(also called an oxidant or oxidizer) can be defined as either: a chemical compoundChemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
that readily transfers oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
atoms, or a substance that gains electrons in a redoxRedoxRedox reactions describe all chemical reactions in which atoms have their oxidation state changed....
chemical reactionChemical reactionA chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
. In both cases, the oxidizing agent becomes reduceRedoxRedox reactions describe all chemical reactions in which atoms have their oxidation state changed....
d in the process.
Oxygen
- OxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
is the elementChemical elementA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
with atomic numberAtomic numberIn chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
8 and represented by the symbol O.
Oxygen sensor
- An oxygen sensorOxygen sensorAn oxygen sensor, or lambda sensor, is an electronic device that measures the proportion of oxygen in the gas or liquid being analyzed. It was developed by the Robert Bosch GmbH company during the late 1960s under the supervision of Dr. Günter Bauman...
, or lambda sensor, is an electronic device that measures the proportion of oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
(O2) in the gas or liquid being analyzed.
Palladium
- PalladiumPalladiumPalladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...
is a rare and lustrous silvery-white metal with the symbol Pd, and its atomic numberAtomic numberIn chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
is 46.
Parallel circuit
- Parallel circuit, if two or more components are connected in parallel they have the same potential difference (voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
) across their ends. The potential differences across the components are the same in magnitude, and they also have identical polarities. Hence, the same voltage is applicable to all circuit components connected in parallel.
Partial oxidation
- In chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, a partial oxidationPartial oxidationPartial oxidation is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell...
(POX) reaction occurs when a substoichiometricStoichiometryStoichiometry is a branch of chemistry that deals with the relative quantities of reactants and products in chemical reactions. In a balanced chemical reaction, the relations among quantities of reactants and products typically form a ratio of whole numbers...
fuel-air mixture is partially combustedCombustionCombustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
in a reformer.
Partial pressure
- In a mixture of ideal gasIdeal gasAn ideal gas is a theoretical gas composed of a set of randomly-moving, non-interacting point particles. The ideal gas concept is useful because it obeys the ideal gas law, a simplified equation of state, and is amenable to analysis under statistical mechanics.At normal conditions such as...
es, each gas has a partial pressurePartial pressureIn a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. The total pressure of a gas mixture is the sum of the partial pressures of each individual gas in the mixture....
which is the pressure which the gas would have if it alone occupied the volume. The total pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
of a gas mixture is the sum of the partial pressures of each individual gas in the mixture.
Particulate
- Particulates, alternatively referred to as particulate matter (PM) or fine particles, are tiny particles of solid or liquid suspended in a gas.
Parts per million
- Parts per millionConcentrationIn chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...
(ppm) denotes the amount of a given substance in a total amount of 1,000,000 regardless of the units of measure used as long as they are the same. e.g. 1 milligram per kilogram. 1 part in 106.
Parts per million by volume
- In atmospheric chemistryAtmospheric chemistryAtmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth's atmosphere and that of other planets is studied. It is a multidisciplinary field of research and draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology and...
and in air pollutionAir pollutionAir pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
regulations, the parts per notation is commonly expressed with a v following, such as ppmv, to indicate parts per million by volumeConcentrationIn chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...
.
Pascal
- The pascalPascal (unit)The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
(symbol: Pa) is the SI derived unitSI derived unitThe International System of Units specifies a set of seven base units from which all other units of measurement are formed, by products of the powers of base units. These other units are called SI derived units, for example, the SI derived unit of area is square metre , and of density is...
of pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
, stressStress (physics)In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...
, Young's modulusYoung's modulusYoung's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...
and tensile strengthTensile strengthUltimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
. It is a measure of perpendicular forceForceIn physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
per unit areaAreaArea is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...
i.e. equivalent to one newton per square meter or one jouleJouleThe joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
per cubic metre.
PEDOT
- Poly(3,4-ethylenedioxythiophene)Poly(3,4-ethylenedioxythiophene)Poly or PEDOT is a conducting polymer based on 3,4-ethylenedioxylthiophene or EDOT monomer. Advantages of this polymer are optical transparency in its conducting state, high stability and moderate band gap and low redox potential...
or PEDOT (or sometimes PEDT) is a conducting polymer based on 3,4-ethylenedioxylthiophene or EDOT monomerMonomerA monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
.
Permeation
- PermeationPermeationPermeation, in physics and engineering, is the penetration of a permeate through a solid, and is related to a material's intrinsic permeability...
, in physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and engineeringEngineeringEngineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, is the penetration of a permeate (such as a liquid, gas, or vaporVaporA vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....
) through a solid, and is related to a material's intrinsic permeability. Permeability is tested by permeation measurement.
Phase transition
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, phase transitionPhase transitionA phase transition is the transformation of a thermodynamic system from one phase or state of matter to another.A phase of a thermodynamic system and the states of matter have uniform physical properties....
or phase change is the transformation of a thermodynamic system from one phasePhase (matter)In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, and chemical composition...
to another.
Phosphoric acid
- Phosphoric acidPhosphoric acidPhosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...
, also known as orthophosphoric acid or phosphoric(V) acid, is a mineral (inorganic) acidMineral acidA mineral acid is an acid derived from one or more inorganic compounds. A mineral acid is not organic and all mineral acids release hydrogen ions when dissolved in water.-Characteristics:...
having the chemical formulaChemical formulaA chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
HHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
3PPhosphorusPhosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
OOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
4.
Phosphoric acid fuel cell
- Phosphoric acid fuel cell (PAFC), a type of fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
that uses liquid phosphoric acidPhosphoric acidPhosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...
as an electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
.
Photoelectrochemical cell
- Photoelectrochemical cellPhotoelectrochemical cellPhotoelectrochemical cells or PECs are solar cells which generate electrical energy from light, including visible light. Some photoelectrochemical cells simply produce electrical energy, while others produce hydrogen in a process similar to the electrolysis of water.-Photogeneration cell:In this...
(PEC), a solar cellSolar cellA solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....
that extracts electrical energy from light, including visible light.
Polybenzimidazole fiber
- Polybenzimidazole (PBI) fiberFiberFiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
(1983) is a synthetic fiberSynthetic fiberSynthetic fibers are the result of extensive research by scientists to improve on naturally occurring animal and plant fibers. In general, synthetic fibers are created by forcing, usually through extrusion, fiber forming materials through holes into the air, forming a thread...
with an extremely high melting pointMelting pointThe melting point of a solid is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard atmospheric pressure...
that also does not ignite.
Polyethylene
- PolyethylenePolyethylenePolyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
or polythene (IUPAC name poly(ethene)) is a thermoplasticThermoplasticThermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
commodity
Polymer
- A polymerPolymerA polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
is a large moleculeMoleculeA molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
(macromoleculeMacromoleculeA macromolecule is a very large molecule commonly created by some form of polymerization. In biochemistry, the term is applied to the four conventional biopolymers , as well as non-polymeric molecules with large molecular mass such as macrocycles...
) composed of repeating structural unitStructural unitIn polymer chemistry, a structural unit is a building block of a polymer chain. It is the result of a monomer which has been polymerized into a long chain....
s connected by covalent chemical bondChemical bondA chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction...
s. See also plasticPlasticA plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
.
Polymer electrolyte membrane
- A polymer electrolyte membrane (PEM), is a fuel cell incorporating a solid polymer membrane used as its electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
. Protons (H+) are transported from the anode to the cathode. The operating temperatureOperating temperatureAn operating temperature is the temperature at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the...
range is generally 60–100°C.
Polytetrafluoroethylene
- In chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, poly(tetrafluoroethene)PolytetrafluoroethylenePolytetrafluoroethylene is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. PTFE is most well known by the DuPont brand name Teflon....
or poly(tetrafluoroethylene) (PTFE) is a synthetic fluoropolymerFluoropolymerA fluoropolymer is a fluorocarbon based polymer with multiple strong carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases.-History:Fluoropolymers were accidentally discovered in 1938 by Dr. Roy J...
which finds numerous applications.
Polymer electrolyte membrane fuel cell
- Polymer electrolyte membrane fuel cell (PEMFC or PEFC), a type of acid-based fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
in which the transport of protonProtonThe proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
s (H+) from the anodeAnodeAn anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....
to the cathodeCathodeA cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...
is through a solid, aqueous membrane impregnated with an appropriate acid. The electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
is a called a polymer electrolyte membrane (PEM). The fuel cells typically run at low temperatures (<100°C).
Potential difference
- In physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, the potential difference or p.d. between two points is the difference of the points' scalar potentialScalar potentialA scalar potential is a fundamental concept in vector analysis and physics . The scalar potential is an example of a scalar field...
, equivalent to the line integral of the field strengthField strengthIn physics, the field strength of a field is the magnitude of its vector value.In theoretical physics, field strength is another name for the curvature form...
between the two points.
Portable fuel cell applications
- Portable fuel cell applicationsPortable fuel cell applicationsFuel cell applications are stationary fuel cell applications and portable fuel cell plications...
(or portable fuel cell power systems) are portablePortablePortable may refer to:* Portable building, a manufactured structure that is built off site and moved in upon completion of site and utility work...
(Movable) fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
applications
Potassium hydroxide
- Potassium hydroxidePotassium hydroxidePotassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
is the inorganic compoundInorganic compoundInorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the formula KPotassiumPotassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
OHHydroxideHydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and a hydrogen atom held together by a covalent bond, and carrying a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, as a ligand, a nucleophile, and a...
.
Power
- In physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, powerPower (physics)In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
(symbol: P) is the rate at which workMechanical workIn physics, work is a scalar quantity that can be described as the product of a force times the distance through which it acts, and it is called the work of the force. Only the component of a force in the direction of the movement of its point of application does work...
is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time.
Power factor
- The power factorPower factorThe power factor of an AC electric power system is defined as the ratio of the real power flowing to the load over the apparent power in the circuit, and is a dimensionless number between 0 and 1 . Real power is the capacity of the circuit for performing work in a particular time...
of an ACAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
electric power system is defined as the ratioRatioIn mathematics, a ratio is a relationship between two numbers of the same kind , usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second In mathematics, a ratio is...
of the real powerAC powerPower in an electric circuit is the rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow...
to the apparent powerAC powerPower in an electric circuit is the rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow...
, and is a number between 0 and 1 (frequently expressed as a percentage, e.g. 0.5 pf = 50% pf).
Power-to-weight ratio
- Power-to-weight ratioPower-to-weight ratioPower-to-weight ratio is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources...
(specific powerPower-to-weight ratioPower-to-weight ratio is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources...
) is a calculation commonly applied to engineEngineAn engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
s and other mobile power sources to enable the comparison of one unit or design to another.
Power per unit of mass
- Power per unit of mass usually refers to the power-to-weight ratioPower-to-weight ratioPower-to-weight ratio is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources...
, measured in kilowatts per kilogramKilogramThe kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
(generally, kWKwkw or KW may refer to:* Kuwait, ISO 3166-1 country code** .kw, the country code top level domain for Kuwait* Kilowatt* Self-ionization of water Kw* Cornish language's ISO 639 code* Kitchener–Waterloo, Ontario, Canada...
/kg).
PReferential OXidation
- Preferential oxidation (PROX) refers to the preferential oxidation of a gas on a catalyst.
Pressure regulator
- A pressure regulatorPressure regulatorA pressure regulator is a valve that automatically cuts off the flow of a liquid or gas at a certain pressure. Regulators are used to allow high-pressure fluid supply lines or tanks to be reduced to safe and/or usable pressures for various applications....
is a valveValveA valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
that automatically cuts off the flow of a liquid or gas at a certain pressure.
Pressure relief valve
- A pressure relief valve is a safety device that relieve in case of overpressure in vessel or piping. The generic term is or pressure relief Valve (PRV) or pressure safety valve (PSV).
Pressure sensor
- A pressure sensorPressure sensorA pressure sensor measures pressure, typically of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually acts as a transducer; it generates a signal as a function of the...
measures the pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
, typically of gases or liquids.
Pressure swing adsorption
- Pressure Swing AdsorptionPressure swing adsorptionPressure swing adsorption is a technology used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an adsorbent material. It operates at near-ambient temperatures and so differs from cryogenic distillation...
(PSA) is a technology used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an adsorbent material.
Pressure vessel
- A pressure vesselPressure vesselA pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.The pressure differential is dangerous and many fatal accidents have occurred in the history of their development and operation. Consequently, their design,...
is a closed container designed to hold gases or liquids at a pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
different from the ambient pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
.
Propane
- PropanePropanePropane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
is a three-carbonCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
alkaneAlkaneAlkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
, normally a gas, but compressible to a liquid that is transportable. See also LPG.
Proton
- The protonProtonThe proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
is a subatomic particleSubatomic particleIn physics or chemistry, subatomic particles are the smaller particles composing nucleons and atoms. There are two types of subatomic particles: elementary particles, which are not made of other particles, and composite particles...
with an electric chargeElectric chargeElectric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
of one positive fundamental unitElementary chargeThe elementary charge, usually denoted as e, is the electric charge carried by a single proton, or equivalently, the absolute value of the electric charge carried by a single electron. This elementary charge is a fundamental physical constant. To avoid confusion over its sign, e is sometimes called...
Proton exchange membrane
- Proton exchange membraneProton exchange membraneA proton exchange membrane or polymer electrolyte membrane is a semipermeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen...
(PEM) is a semipermeable membraneSemipermeable membraneA semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion".The rate of...
generally made from ionomerIonomerAn ionomer is a polymer that comprises repeat units of both electrically neutral repeating units and a fraction of ionized units...
s and designed to conduct protonsProton conductorA proton conductor is an electrolyte, typically a solid electrolyte, in which H+ are the primary charge carriers.-Composition:For practical applications, proton conductors are usually solid materials. Typical materials are polymers or ceramic. Typically the pores in practical materials are small...
while being impermeable to gases such as oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
or hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
.
Proton exchange membrane fuel cell
- Proton exchange membrane fuel cellProton exchange membrane fuel cellProton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...
(PEMFC) a type of fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
based on a polymerPolymerA polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
electrolyteElectrolyteIn chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
membraneArtificial membraneAn artificial membrane, or synthetic membrane, is a synthetically created membrane which is usually intended for separation purposes in laboratory or in industry. Synthetic membranes have been successfully used for small and large-scale industrial processes since the middle of twentieth century. A...
.
Protonic ceramic fuel cell
- Protonic ceramic fuel cellProtonic ceramic fuel cellThe Protonic ceramic fuel cell or PCFC is a fuel cell based on a ceramic electrolyte material that exhibits high protonic conductivity at elevated temperatures....
(PCFC) based on a ceramic electrolyte material that exhibits high protonic conductivity at elevated temperatures.
Reactor
- Reactor, see: bioreactor, membrane reactorMembrane reactorA membrane reactor is a piece of chemical equipment that combines a catalyst-filled reaction chamber with a membrane to add reactants or remove products of the reaction.Chemical reactors making use of membranes are usually referred to as membrane reactors...
and chemical reactorChemical reactorIn chemical engineering, chemical reactors are vessels designed to contain chemical reactions. The design of a chemical reactor deals with multiple aspects of chemical engineering. Chemical engineers design reactors to maximize net present value for the given reaction...
.
Reagent
- A reagentReagentA reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
or reactant is a substance or compound consumed during a chemical reactionChemical reactionA chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
.
Rectifier
- A rectifierRectifierA rectifier is an electrical device that converts alternating current , which periodically reverses direction, to direct current , which flows in only one direction. The process is known as rectification...
is an electrical device that converts alternating currentAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
(AC) to direct currentDirect currentDirect current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
(DC), a process known as rectification.
Redox
- RedoxRedoxRedox reactions describe all chemical reactions in which atoms have their oxidation state changed....
(shorthand for reduction-oxidation reaction) describes all chemical reactions in which atoms have their oxidation numberOxidation numberIn coordination chemistry, the oxidation number of a central atom in a coordination compound is the charge that it would have if all the ligands were removed along with the electron pairs that were shared with the central atom. Oxidation numbers are often confused with oxidation states.The...
(oxidation stateOxidation stateIn chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
) changed.
Reformate
- Reformate, hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
fuel that has been processed into hydrogen and other products for use in fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s.
Reformed Methanol Fuel Cell
- Reformed methanol fuel cellReformed methanol fuel cellReformed Methanol Fuel Cell or Indirect Methanol Fuel Cell systems are a subcategory of proton-exchange fuel cells where, the fuel, methanol , is reformed, before being fed into the fuel cell...
(RMFC) or Indirect Methanol Fuel Cell (IMFC)s are a subcategory of proton-exchange fuel cellsProton exchange membrane fuel cellProton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower...
where, the fuel, methanolMethanolMethanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
(CH3OH), is reformed, before being fed into the fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
.
Reformer
- A hydrogen reformer another name for steam reformingSteam reformingFossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to...
a device that extracts hydrogen from other fuels, typically methanol or gasoline, not to be confused with the process catalytic reformingCatalytic reformingCatalytic reforming is a chemical process used to convert petroleum refinery naphthas, typically having low octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline...
Reforming
- A chemical process in which hydrogen containing fuels react with steam, oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, or both to produce a hydrogen-rich gas stream. (syngasSyngasSyngas is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, and in some types of waste-to-energy...
)
Reformulated gasoline
- Gasoline that is blended so that, on average, it significantly reduces volatile organic compounds and air toxics emissions relative to conventional gasolines.
Regenerative fuel cell
- A fuel cell that produces electricity from hydrogen and oxygen and can use electricity from solar power or some other source to divide the excess water into oxygen and hydrogen fuel to be re-used by the fuel cell. See Regenerative fuel cell.
Relief valve
- The relief valveRelief valveThe relief valve is a type of valve used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure, or fire....
is a type of valveValveA valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
used to control or limit the pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
in a system or vessel which can build up by a process upset, instrument or equipment failure, or fire.
Renewable energy
- Renewable energyRenewable energyRenewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...
is energy generated from natural resourceNatural resourceNatural resources occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. A natural resource is often characterized by amounts of biodiversity and geodiversity existent in various ecosystems....
s—such as sunlightSunlightSunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
, Including solar and radiant energyRadiant energyRadiant energy is the energy of electromagnetic waves. The quantity of radiant energy may be calculated by integrating radiant flux with respect to time and, like all forms of energy, its SI unit is the joule. The term is used particularly when radiation is emitted by a source into the...
, windWindWind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
, rainRainRain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
, tides and geothermal heat—which are renewableRenewable resourceA renewable resource is a natural resource with the ability of being replaced through biological or other natural processes and replenished with the passage of time...
(naturally replenished).
Reservoir
- A reservoirReservoirA reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
is, most broadly, a place or hollow vessel where something fluidFluidIn physics, a fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas and, to some extent, plastic solids....
is kept in reserve, for later use.
Response time
- In technologyTechnologyTechnology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
, response time is the timeTimeTime is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
a systemSystemSystem is a set of interacting or interdependent components forming an integrated whole....
or functional unit takes to react to a given input.
Reversible fuel cell
- Reversible fuel cell (RFC), a fuel cell that can consume chemical A to produce electricity and chemical B and be reversed to consume electricity and chemical B to produce chemical A.
Reynolds number
- In fluid mechanicsFluid mechanicsFluid mechanics is the study of fluids and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; fluid kinematics, the study of fluids in motion; and fluid dynamics, the study of the effect of forces on fluid motion...
and heat transferHeat transferHeat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
, the Reynolds number
is a dimensionless number that gives a measure of the ratioRatioIn mathematics, a ratio is a relationship between two numbers of the same kind , usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second In mathematics, a ratio is...
of inertiaInertiaInertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...
l forceForceIn physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
s (
) to viscousViscosityViscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
forces (
) and, consequently, it quantifies the relative importance of these two types of forces for given flow conditions.
Rupture disc
- A rupture disk or bursting disc is a pressure reliefRelief valveThe relief valve is a type of valve used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure, or fire....
device that protects a vessel or system from overpressurization.
Safety shutoff valve
- Safety shut-off valves are safety valveSafety valveA safety valve is a valve mechanism for the automatic release of a substance from a boiler, pressure vessel, or other system when the pressure or temperature exceeds preset limits....
s used to close a line and stop the flow of material.
Safety valve
- A safety valveSafety valveA safety valve is a valve mechanism for the automatic release of a substance from a boiler, pressure vessel, or other system when the pressure or temperature exceeds preset limits....
is a valveValveA valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
mechanism for the automatic release of a gas from a boilerBoilerA boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...
, pressure vesselPressure vesselA pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.The pressure differential is dangerous and many fatal accidents have occurred in the history of their development and operation. Consequently, their design,...
, or other systemSystemSystem is a set of interacting or interdependent components forming an integrated whole....
when the pressure or temperature exceeds preset limits.
Salt bridge
- A salt bridgeSalt bridgeA salt bridge, in chemistry, is a laboratory device used to connect the oxidation and reduction half-cells of a galvanic cell , a type of electrochemical cell...
, in chemistryChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, is a laboratory device used to connect the oxidation and reductionRedoxRedox reactions describe all chemical reactions in which atoms have their oxidation state changed....
half-cells of a galvanic cellGalvanic cellA Galvanic cell, or Voltaic cell, named after Luigi Galvani, or Alessandro Volta respectively, is an electrochemical cell that derives electrical energy from spontaneous redox reaction taking place within the cell...
(voltaic cell), a type of electrochemical cellElectrochemical cellAn electrochemical cell is a device capable of either deriving electrical energy from chemical reactions, or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt "battery"...
. Salt bridge usually comes in two types: glass tube and filter paperFilter paperFilter paper is a semi-permeable paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine solids from liquids or air.-Properties:Filter paper comes in various porosities and grades depending on the applications it is meant for...
.
Scrubber
- ScrubberScrubberScrubber systems are a diverse group of air pollution control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. Traditionally, the term "scrubber" has referred to pollution control devices that use liquid to wash unwanted pollutants from a gas stream...
systems are a diverse group of air pollutionAir pollutionAir pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
control devices that can be used to remove some particulates and/or gases from industrial exhaust streams.
Sensor
- A sensorSensorA sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...
is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument.
Series circuit
- Series circuits are sometimes called current-coupled or daisy chainDaisy chain (electrical engineering)In electrical and electronic engineering a daisy chain is a wiring scheme in which multiple devices are wired together in sequence or in a ring...
-coupled. The current that flows in a series circuit has to flow through every component in the circuit. Therefore, all of the components in a series connection carry the same current. It has been noted that current flows in series.
Service life
- A product's service lifeService lifeA product's service life is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be 'serviceable' or supported by its manufacturer....
is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be 'serviceable' or supported by its originating manufacturer.
Short circuit
- A short circuitShort circuitA short circuit in an electrical circuit that allows a current to travel along an unintended path, often where essentially no electrical impedance is encountered....
(sometimes abbreviated to short or s/c) allows a currentElectric currentElectric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
along a different path from the one intended.
Sodium borohydride
- Sodium borohydrideSodium borohydrideSodium borohydride, also known as sodium tetrahydridoborate, is an inorganic compound with the formula NaBH4. This white solid, usually encountered as a powder, is a versatile reducing agent that finds wide application in chemistry, both in the laboratory and on a technical scale. Large amounts are...
, also known as sodium tetrahydroborate, has the chemical formulaChemical formulaA chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
NaSodiumSodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
BBoronBoron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...
HHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
4.
Solenoid valve
- A solenoid valveSolenoid valveA solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled by an electric current through a solenoid: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports...
is an electromechanical valveValveA valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
for use with liquid or gas controlled by running or stopping an electrical current through a solenoidSolenoidA solenoid is a coil wound into a tightly packed helix. In physics, the term solenoid refers to a long, thin loop of wire, often wrapped around a metallic core, which produces a magnetic field when an electric current is passed through it. Solenoids are important because they can create...
, which is a coil of wire, thus changing the state of the valve.
Solid oxide electrolyser cell
A solid oxide electrolyser cellSolid oxide electrolyser cell
A solid oxide electrolyzer cell is a solid oxide fuel cell that is run in regenerative mode to achieve the electrolysis of water and which uses a solid oxide, or ceramic, electrolyte to produce oxygen and hydrogen gas.-Principle:...
(SOEC) is a solid oxide fuel cell set in regenerative mode for the electrolysis of water
Electrolysis of water
Electrolysis of water is the decomposition of water into oxygen and hydrogen gas due to an electric current being passed through the water.-Principle:...
with a solid oxide, or ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
, electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
to produce oxygen and hydrogen gas.
Solid oxide fuel cell
- A solid oxide fuel cell (SOFC) is an electrochemical conversion device that produces electricity directly from oxidizing a fuel.
Solubility
- SolubilitySolubilitySolubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
is a characteristic physical propertyPhysical propertyA physical property is any property that is measurable whose value describes a physical system's state. The changes in the physical properties of a system can be used to describe its transformations ....
referring to the ability of a given substance, the soluteSolutionIn chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
, to dissolve in a solventSolventA solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
.
Sorption
- SorptionSorptionSorption refers to the action of absorption* Absorption is the incorporation of a substance in one state into another of a different state ....
refers to the action of both absorption and adsorptionAdsorptionAdsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
takes place simultaneously.
Specific gravity
- Specific gravitySpecific gravitySpecific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
is defined as the ratio of the densityDensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
of a given solid or liquid substance to the density of H2O at a specific temperature and pressure, typically at 4°C (39°F) and 1 atm (29.92 inHg) , making it a dimensionless quantity
Specific heat capacity
- Specific heat capacity, also known simply as specific heat, is the measure of the heat energyEnergyIn physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
required to increase the temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
of a unit quantityQuantityQuantity is a property that can exist as a magnitude or multitude. Quantities can be compared in terms of "more" or "less" or "equal", or by assigning a numerical value in terms of a unit of measurement. Quantity is among the basic classes of things along with quality, substance, change, and relation...
Specific power
- In engineeringEngineeringEngineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, the term specific power can refer to powerPower (physics)In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
either per unit of massMassMass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
, volumeVolumeVolume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
or areaAreaArea is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...
.
Specific weight
- The specific weightSpecific weightThe specific weight is the weight per unit volume of a material. The symbol of specific weight is γ ....
(also known as the unit weight) is the weightWeightIn science and engineering, the weight of an object is the force on the object due to gravity. Its magnitude , often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus:...
per unit volumeVolumeVolume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
of a material
Stack
- Stack, to deliver the desired amount of energy, the fuel cells can be combined in series and parallel circuitsSeries and parallel circuitsComponents of an electrical circuit or electronic circuit can be connected in many different ways. The two simplest of these are called series and parallel and occur very frequently. Components connected in series are connected along a single path, so the same current flows through all of the...
, where series yield higher voltage, and parallel allows a stronger current to be drawn. Such a design is called a fuel cell stack.
Standard cubic foot
- A standard cubic footStandard cubic footA standard cubic foot is a measure of quantity of gas, equal to a cubic foot of volume at 60 degrees Fahrenheit and either 14.696 psi or 14.73 psi of pressure.A standard cubic foot is thus not a unit of volume but of quantity, and the conversion to normal cubic metres is...
(SFC) is a measure of quantity of gas, equal to a cubic foot of volume at 60 degrees FahrenheitFahrenheitFahrenheit is the temperature scale proposed in 1724 by, and named after, the German physicist Daniel Gabriel Fahrenheit . Within this scale, the freezing of water into ice is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees...
and either 14.696 pounds-force per square inch (1 atmAtmosphere (unit)The standard atmosphere is an international reference pressure defined as 101325 Pa and formerly used as unit of pressure. For practical purposes it has been replaced by the bar which is 105 Pa...
or 101.325 kPa) or 14.73 psi (30 inHg or 101.6 kPa) of pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
.
Standard electrode potential
- In electrochemistryElectrochemistryElectrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
, the standard electrode potentialStandard electrode potentialIn electrochemistry, the standard electrode potential, abbreviated E° or E , is the measure of individual potential of a reversible electrode at standard state, which is with solutes at an effective concentration of 1 mol dm−3, and gases at a pressure of 1 atm...
, abbreviated Eo, E0, or EO(with a superscript plimsoll character, pronounced nought), is the measure of individual potential of a reversible electrode (at equilibrium) at standard stateStandard stateIn chemistry, the standard state of a material is a reference point used to calculate its properties under different conditions. In principle, the choice of standard state is arbitrary, although the International Union of Pure and Applied Chemistry recommends a conventional set of standard states...
, which is with solutes at an effective concentration of 1 mol/kg, and gases at a pressure of 1 atmosphere / 100 kPa (kilopascals).
Stationary fuel cell applications
- Stationary fuel cell applications (or stationary fuel cell power systems) are stationary (Not moving) fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
applications
Steady state
- Steady stateSteady stateA system in a steady state has numerous properties that are unchanging in time. This implies that for any property p of the system, the partial derivative with respect to time is zero:...
is a more general situation than dynamic equilibriumDynamic equilibriumA dynamic equilibrium exists once a reversible reaction ceases to change its ratio of reactants/products, but substances move between the chemicals at an equal rate, meaning there is no net change. It is a particular example of a system in a steady state...
. If a systemSystemSystem is a set of interacting or interdependent components forming an integrated whole....
is in steady state, then the recently observed behavior of the system will continue into the future.
Steam reforming
- Steam reformingSteam reformingFossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to...
(SR), hydrogen reforming or catalytic oxidation, is a method of producing hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
from hydrocarbons at high temperatures (700 – 1100 °C) in the presence of a metal-based catalyst (nickelNickelNickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
).
Switched-mode power supply
- A switched-mode power supplySwitched-mode power supplyA switched-mode power supply is an electronic power supply that incorporates a switching regulator in order to be highly efficient in the conversion of electrical power...
, switching-mode power supply or SMPS, is an electronic power supplyPower supplyA power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy...
unit (PSU) that incorporates a switching regulator.
Syngas
- SyngasSyngasSyngas is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, and in some types of waste-to-energy...
(from synthesis gas) is the name given to a gas mixture that contains varying amounts of carbon monoxideCarbon monoxideCarbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
and hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
generated by the gasificationGasificationGasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...
of a carbon-containing fuel to a gaseous product with a heating value.
Tafel equation
- The Tafel equationTafel equationThe Tafel equation is an equation in electrochemical kinetics relating the rate of an electrochemical reaction to the overpotential. The Tafel equation was first deduced experimentally and was later shown to have a theoretical justification...
relates the rate of an electrochemicalElectrochemistryElectrochemistry is a branch of chemistry that studies chemical reactions which take place in a solution at the interface of an electron conductor and an ionic conductor , and which involve electron transfer between the electrode and the electrolyte or species in solution.If a chemical reaction is...
reaction to the overpotentialOverpotentialOverpotential is an electrochemical term which refers to the potential difference between a half-reaction's thermodynamically determined reduction potential and the potential at which the redox event is experimentally observed. The term is directly related to a cell's voltage efficiency...
.
Tar
- TarTarTar is modified pitch produced primarily from the wood and roots of pine by destructive distillation under pyrolysis. Production and trade in tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden vessels against rot. The largest...
is a viscousViscosityViscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
black liquid derived from the destructive distillationDestructive distillationDestructive distillation is the chemical process involving the decomposition of feedstock by heating to a high temperature; the term generally applies to processing of organic material in the absence of air or in the presence of limited amounts of oxygen or other reagents, catalysts, or solvents,...
of organic matter.
Technology assessment
- Technology assessmentTechnology assessmentTechnology assessment Technology assessment Technology assessment (TA, German Tenteractive, and communicative process that aims to contribute to the formation of public and political opinion on societal aspects of science and technology.- General description :...
(TA, German Technikfolgenabschätzung) is the study and evaluationEvaluationEvaluation is systematic determination of merit, worth, and significance of something or someone using criteria against a set of standards.Evaluation often is used to characterize and appraise subjects of interest in a wide range of human enterprises, including the arts, criminal justice,...
of new technologiesTechnologyTechnology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
.
Technology lifecycle
- Most new technologies follow a similar technology maturity lifecycleTechnology lifecycleMost new technologies follow a similar technology maturity lifecycle describing the technological maturity of a product. This is not similar to a product life cycle, but applies to an entire technology, or a generation of a technology....
describing the technological maturity of a product.
Technology readiness level
- Technology readiness levelTechnology Readiness LevelTechnology Readiness Level is a measure used by some United States government agencies and many of the world's major companies to assess the maturity of evolving technologies prior to incorporating that technology into a system or subsystem...
(TRL) is a measure used by some United States government agencies and many of the world's major companies (and agencies) to assess the maturity of evolving technologiesMature technologyA mature technology is a technology that has been in use for long enough that most of its initial faults and inherent problems have been removed or reduced by further development...
(materials, components, devices, etc.) prior to incorporating that technology into a system or subsystem.
Technology validation
- Technology validation, confirming that technical targets for a given technology have been met.
Temperature
- TemperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
is a physicalPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
property of a systemPhysical systemIn physics, the word system has a technical meaning, namely, it is the portion of the physical universe chosen for analysis. Everything outside the system is known as the environment, which in analysis is ignored except for its effects on the system. The cut between system and the world is a free...
that underlies the common notions of hot and cold
Terbium
- TerbiumTerbiumTerbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife...
is used as a crystal stabilizer of fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s which operate at elevated temperatures, together with ZrO2.
Thermal conductivity
- In physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, thermal conductivityThermal conductivityIn physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....
,
, is the property of a material that indicates its ability to conduct heatHeatIn physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
.
Thermal efficiency
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, the thermal efficiencyThermal efficiencyIn thermodynamics, the thermal efficiency is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, a boiler, a furnace, or a refrigerator for example.-Overview:...
(
) is a dimensionlessDimensionless quantityIn dimensional analysis, a dimensionless quantity or quantity of dimension one is a quantity without an associated physical dimension. It is thus a "pure" number, and as such always has a dimension of 1. Dimensionless quantities are widely used in mathematics, physics, engineering, economics, and...
performance measure of a thermal device
Thermal expansion
- When the temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
of a substance changes, the energy that is stored in the intermolecular bonds between atoms changes. When the stored energy increases, so does the length of the molecular bonds. As a result, solids typically expand in response to heating and contract on cooling; this dimensional response to temperature change is expressed by its coefficient of thermal expansionThermal expansionThermal expansion is the tendency of matter to change in volume in response to a change in temperature.When a substance is heated, its particles begin moving more and thus usually maintain a greater average separation. Materials which contract with increasing temperature are rare; this effect is...
.
Thermal partial oxidation
- Thermal partial oxidation (TPOX) is a thermal partial oxidationPartial oxidationPartial oxidation is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell...
reaction, which is dependent on the air-fuel ratioAir-fuel ratioAir–fuel ratio is the mass ratio of air to fuel present in an internal combustion engine. If exactly enough air is provided to completely burn all of the fuel, the ratio is known as the stoichiometric mixture, often abbreviated to stoich...
, proceed at temperatures of 1200°CCelsiusCelsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
and above.
Thermoelectricity
- Thermoelectricity (thermo-electricity) refers to a class of phenomena in which a temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
difference creates an electric potentialElectric potentialIn classical electromagnetism, the electric potential at a point within a defined space is equal to the electric potential energy at that location divided by the charge there...
or an electric potential creates a temperature difference.
Thermoplastic
A thermoplasticThermoplastic
Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
is a plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
that melts
Melting
Melting, or fusion, is a physical process that results in the phase change of a substance from a solid to a liquid. The internal energy of a substance is increased, typically by the application of heat or pressure, resulting in a rise of its temperature to the melting point, at which the rigid...
to a liquid when heated and freezes to a brittle
Brittle
A material is brittle if, when subjected to stress, it breaks without significant deformation . Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a snapping sound. Brittle materials include most ceramics and glasses ...
, very glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
y state when cooled sufficiently.
Thermoplastic elastomer
- Thermoplastic elastomers (TPE), sometimes referred to as thermoplastic rubbers, are a class of copolymers or a physical mix of polymers (usually a plastic and a rubber) which consist of materials with both thermoplasticThermoplasticThermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
and elastomerElastomerAn elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...
ic properties.
Transducer
- A transducerTransducerA transducer is a device that converts one type of energy to another. Energy types include electrical, mechanical, electromagnetic , chemical, acoustic or thermal energy. While the term transducer commonly implies the use of a sensor/detector, any device which converts energy can be considered a...
is a device, usually electricalElectricityElectricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
, electronicElectronicsElectronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
, electro-mechanical, electromagneticElectromagnetismElectromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
, photonic, or photovoltaic that converts one type of energy or physical attribute to another for various purposes including measurement or information transfer (for example, pressure sensorPressure sensorA pressure sensor measures pressure, typically of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually acts as a transducer; it generates a signal as a function of the...
s).
Transfer switch
A transfer switchTransfer switch
A transfer switch is an electrical switch that reconnects electric power source from its primary source to a standby source. Switches may be manually or automatically operated...
allows switching from a primary power source to a secondary or tertiary power source and are employed in some electrical power distribution systems.
Transformer
- A transformerTransformerA transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...
is a device that transfers electrical energy from one circuitElectrical networkAn electrical network is an interconnection of electrical elements such as resistors, inductors, capacitors, transmission lines, voltage sources, current sources and switches. An electrical circuit is a special type of network, one that has a closed loop giving a return path for the current...
to another through inductively coupledInductive couplingIn electrical engineering, two conductors are referred to as mutual-inductively coupled or magnetically coupled when they are configured such that change in current flow through one wire induces a voltage across the ends of the other wire through electromagnetic induction...
electrical conductorElectrical conductorIn physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...
s.
Triple point
- In thermodynamicsThermodynamicsThermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
, the triple pointTriple pointIn thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases of that substance coexist in thermodynamic equilibrium...
of a substance is the temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
and pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
at which three phasesPhase (matter)In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, and chemical composition...
(for example, gas, liquid, and solid) of that substance coexist in thermodynamic equilibriumThermodynamic equilibriumIn thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, radiative equilibrium, and chemical equilibrium. The word equilibrium means a state of balance...
.
Turbocharger
- TurbochargerTurbochargerA turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...
, a device used for increasing the pressure and densityDensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
of a fluid entering a fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
power plant using a compressor driven by a turbine that extracts energy from the exhaust gas.
Turbocompressor
- Turbocompressor, a machine for compressing air or other fluid (reactant if supplied to a fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
system) in order to increase the reactant pressure and concentration.
Uninterruptible power supply
- An uninterruptible power supplyUninterruptible power supplyAn uninterruptible power supply, also uninterruptible power source, UPS or battery/flywheel backup, is an electrical apparatus that provides emergency power to a load when the input power source, typically mains power, fails...
(UPS), also known as a continuous power supply (CPS) is a device which maintains a continuous supply of electric powerElectric powerElectric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
to connected equipment by supplying power from a separate source when utility power is not available.
Unitized regenerative fuel cell
A unitized regenerative fuel cellUnitized regenerative fuel cell
A unitized regenerative fuel cell is a fuel cell based on the proton exchange membrane which can do the electrolysis of water in regenerative mode and function in the other mode as a fuel cell recombining oxygen and hydrogen gas to produce electricity. Both modes are done with the same fuel cell...
(URFC) is a fuel cell
Fuel cell
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
based on the proton exchange membrane
Proton exchange membrane
A proton exchange membrane or polymer electrolyte membrane is a semipermeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen...
which can do the electrolysis of water
Electrolysis of water
Electrolysis of water is the decomposition of water into oxygen and hydrogen gas due to an electric current being passed through the water.-Principle:...
in regenerative mode and function in the other mode as a fuel cell recombining oxygen and hydrogen gas to produce electricity.
Vacuum pump
- A vacuum pumpVacuum pumpA vacuum pump is a device that removes gas molecules from a sealed volume in order to leave behind a partial vacuum. The first vacuum pump was invented in 1650 by Otto von Guericke.- Types :Pumps can be broadly categorized according to three techniques:...
is a device that removes gas molecules from a sealed volume in order to leave behind a partial vacuumVacuumIn everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
.
Vapor–liquid equilibrium
- Vapor–liquid equilibrium, abbreviated as VLE by some, is a condition where a liquid and its vaporVaporA vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....
(gas phase) are in equilibriumChemical equilibriumIn a chemical reaction, chemical equilibrium is the state in which the concentrations of the reactants and products have not yet changed with time. It occurs only in reversible reactions, and not in irreversible reactions. Usually, this state results when the forward reaction proceeds at the same...
with each other, a condition or state where the rate of evaporationEvaporationEvaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
(liquid changing to vapor) equals the rate of condensationCondensationCondensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
(vapor changing to liquid) on a molecular level such that there is no net (overall) vapor-liquid interconversion.
Vapor pressure
- Vapor pressureVapor pressureVapor pressure or equilibrium vapor pressure is the pressure of a vapor in thermodynamic equilibrium with its condensed phases in a closed system. All liquids have a tendency to evaporate, and some solids can sublimate into a gaseous form...
(also known as equilibrium vapor pressure or saturation vapor pressure), is the pressurePressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
of a vaporVaporA vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....
in equilibriumThermodynamic equilibriumIn thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, radiative equilibrium, and chemical equilibrium. The word equilibrium means a state of balance...
with its non-vapor phasePhase (matter)In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, and chemical composition...
s.
Vapor recovery
- Vapor recoveryVapor recoveryVapor recovery is the process of recovering the vapors of gasoline or other fuels, so that they do not escape into the atmosphere...
(or vapour) recovery is the process of recovering the vaporVaporA vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....
s of gasolineGasolineGasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
or other fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
s, so that they do not escape into the atmosphereAtmosphereAn atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
.
Voltage
- Electrical tension (or voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
after its SI unit, the voltVoltThe volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
) is the difference of electrical potential between two points of an electrical or electronic circuitElectronic circuitAn electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
, expressed in voltVoltThe volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
s.
Voltage converter
- A voltage converterVoltage converterA voltage converter changes the voltage of an electrical power source. It may be combined with other components to create a power supply.-AC and DC:...
changes the voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
of an electrical power source and is usually combined with other components to create a power supplyPower supplyA power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy...
.
Voltage drop
- Voltage dropVoltage dropVoltage drop is the reduction in voltage in the passive elements of an electrical circuit. Voltage drops across conductors, contacts, connectors and source internal resistances are undesired as they reduce the supplied voltage while voltage drops across loads and other electrical and electronic...
is the reduction in voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
in an electrical circuitElectrical networkAn electrical network is an interconnection of electrical elements such as resistors, inductors, capacitors, transmission lines, voltage sources, current sources and switches. An electrical circuit is a special type of network, one that has a closed loop giving a return path for the current...
between the source and load.
Voltage regulator
- A voltage regulatorVoltage regulatorA voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components...
is an electricalElectricityElectricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
regulatorRegulator (automatic control)In automatic control, a regulator is a device which has the function of maintaining a designated characteristic. It performs the activity of managing or maintaining a range of values in a machine. The measurable property of a device is managed closely by specified conditions or an advance set...
designed to automatically maintain a constant voltageVoltageVoltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
level.
Volumetric energy density
- Volumetric energy densityEnergy densityEnergy density is a term used for the amount of energy stored in a given system or region of space per unit volume. Often only the useful or extractable energy is quantified, which is to say that chemically inaccessible energy such as rest mass energy is ignored...
, potential energy in a given volumeVolumeVolume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
of fuelFuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
.
Volumetric flow rate
- The volumetric flow rateVolumetric flow rateThe volumetric flow rate in fluid dynamics and hydrometry, is the volume of fluid which passes through a given surface per unit time...
in fluid dynamicsFluid dynamicsIn physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
and hydrometryHydrometryHydrometry is the monitoring of the components of the hydrological cycle including rainfall, groundwater characteristics, as well as water quality and flow characteristics of surface waters...
, (also known as volume flow rate or rate of fluid flow) is the volume of fluid which passes through a given surface per unit time (for example cubic meters per second [m3 s−1] in SISiSi, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...
units, or cubic feetCubic footThe cubic foot is an Imperial and US customary unit of volume, used in the United States and the United Kingdom. It is defined as the volume of a cube with sides of one foot in length.-Conversions:- Symbols :...
per second [cu ft/s]). It is usually represented by the symbol Q.
Volumetric heat capacity
- Volumetric heat capacityVolumetric heat capacityVolumetric heat capacity , also termed volume-specific heat capacity, describes the ability of a given volume of a substance to store internal energy while undergoing a given temperature change, but without undergoing a phase change...
(VHC) describes the ability of a given volumeVolumeVolume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
of a substance to store internal energyInternal energyIn thermodynamics, the internal energy is the total energy contained by a thermodynamic system. It is the energy needed to create the system, but excludes the energy to displace the system's surroundings, any energy associated with a move as a whole, or due to external force fields. Internal...
while undergoing a given temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
change, but without undergoing a phase change.
Water
- WaterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
(H2O) in typical usage, water refers only to its liquid form or state, but the substance also has a solid state, iceIceIce is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
, and a gaseous state, water vaporWater vaporWater vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
or steamSteamSteam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
.
Water gas shift reaction
- The water gas shift reactionWater gas shift reactionThe water-gas shift reaction is a chemical reaction in which carbon monoxide reacts with water vapor to form carbon dioxide and hydrogen:The water-gas shift reaction is an important industrial reaction. It is often used in conjunction with steam reforming of methane or other hydrocarbons, which is...
(WGS) is a chemical reactionChemical reactionA chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
in which carbon monoxideCarbon monoxideCarbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
reacts with waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
to form carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
and hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
Water purification
- Water purificationWater purificationWater purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...
is the process of removing contaminants and other harmful microorganisms from a raw water source.
Water vapor
- Water vaporWater vaporWater vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
or water vapour (see spelling differencesAmerican and British English spelling differencesOne of the ways in which American English and British English differ is in spelling.-Historical origins:In the early 18th century, English spelling was not standardized. Differences became noticeable after the publishing of influential dictionaries...
), also aqueous vapor, is the gas phase of water.
Watt
- The wattWattThe watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
(symbol: W) is the SISiSi, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...
derived unitSI derived unitThe International System of Units specifies a set of seven base units from which all other units of measurement are formed, by products of the powers of base units. These other units are called SI derived units, for example, the SI derived unit of area is square metre , and of density is...
of powerPower (physics)In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
, equal to one jouleJouleThe joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...
of energy per secondSecondThe second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
. It measures a rate of energy use or production.
W/kg
- Kilowatts per kilogramKilogramThe kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
(generally, WWattThe watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
/kg).The power per unit of mass in relation to the power-to-weight ratioPower-to-weight ratioPower-to-weight ratio is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources...
.
Wt.%
- The term wt.% (abbreviation for weight percent) is widely used in hydrogen storageHydrogen storageHydrogen storage describes the methods for storing H2 for subsequent use. The methods span many approaches, including high pressures, cryogenics, and chemical compounds that reversibly release H2 upon heating...
research to denote the amount of hydrogen stored on a weight basis (the term mass % is also occasionally used). The term can be used for materials that store hydrogen or for the entire storage system (e.g., material or compressed/liquid hydrogen as well as the tank and other equipment required to contain the hydrogen such as insulation, valves, regulators, etc.). For example, 6 wt.% on a system-basis means that 6% of the entire system by weight is hydrogen. On a material basis, the wt.% is the mass of hydrogen divided by the mass of material plus hydrogen.
Yttria-stabilized zirconia
- Yttria-stabilized zirconiaYttria-stabilized zirconiaYttria-stabilized zirconia is a zirconium-oxide based ceramic, in which the particular crystal structure of zirconium oxide is made stable at room temperature by an addition of yttrium oxide...
(YSZ) is a zirconium-oxideZirconium dioxideZirconium dioxide , sometimes known as zirconia , is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the rare mineral baddeleyite. The high temperature cubic crystalline form is rarely found in nature as mineral tazheranite O2...
based ceramic
Zinc-air battery
- A Zinc-air batteryZinc-air batteryZinc–air batteries , and zinc–air fuel cells, are electro-chemical batteries powered by oxidizing zinc with oxygen from the air. These batteries have high energy densities and are relatively inexpensive to produce...
(non-rechargeable), and zinc-air fuel cellFuel cellA fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s, (mechanically-rechargeable) are electro-chemical batteriesBattery (electricity)An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
powered by the oxidation of zincZincZinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
with oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
from the air.
Zinc oxide
- Zinc oxideZinc oxideZinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...
is a chemical compoundChemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formulaChemical formulaA chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
ZnO. (sulfurSulfurSulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
sorbent)
Acronyms
| Acronym | – |
|---|---|
| AAEM | alkali anion exchange membrane Alkali anion exchange membrane An alkali anion exchange membrane is a semipermeable membrane generally made from ionomers and designed to conduct anions while being impermeable to gases such as oxygen or hydrogen... |
| AC | alternating current Alternating current In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction.... |
| AFC | alkaline fuel cell Alkaline fuel cell The alkaline fuel cell , also known as the Bacon fuel cell after its British inventor, is one of the most developed fuel cell technologies. NASA has used alkaline fuel cells since the mid-1960s, in Apollo-series missions and on the Space Shuttle. AFCs consume hydrogen and pure oxygen producing... |
| ATR | autothermal reforming |
| APU | auxiliary power unit Auxiliary power unit An auxiliary power unit is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft, as well as some large land vehicles.-Function:... |
| BASE | beta-alumina solid electrolyte Beta-alumina solid electrolyte Beta-alumina solid electrolyte is a fast ion conductor material used as a membrane in several types of molten salt electrochemical cell... |
| BOP | balance of plant |
| BTU | British thermal unit British thermal unit The British thermal unit is a traditional unit of energy equal to about 1055 joules. It is approximately the amount of energy needed to heat of water, which is exactly one tenth of a UK gallon or about 0.1198 US gallons, from 39°F to 40°F... |
| °C | celsius Celsius Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death... |
| C | carbon Carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds... |
| C | coulomb |
| ca. or c. | circa Circa Circa , usually abbreviated c. or ca. , means "approximately" in the English language, usually referring to a date... |
| CGH2 | compressed hydrogen Compressed hydrogen Compressed hydrogen is the gaseous state of the element hydrogen kept under pressure. Compressed hydrogen in hydrogen tanks at 350 bar and 700 bar is used for mobile hydrogen storage in hydrogen vehicles... |
| CH4 | methane Methane Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel... |
| CH3CH2OH | ethanol Ethanol Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a... |
| CH3OH | methanol Methanol Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol... |
| CHP | combined heat and power Combined Heat and Power Combined Heat and Power may refer to:* Cogeneration* Combined Heat and Power Solar... |
| CI | chloride ion |
| CNG | compressed natural gas Compressed natural gas Compressed natural gas is a fossil fuel substitute for gasoline , diesel, or propane/LPG. Although its combustion does produce greenhouse gases, it is a more environmentally clean alternative to those fuels, and it is much safer than other fuels in the event of a spill... |
| CNT | carbon nanotube Carbon nanotube Carbon nanotubes are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1, significantly larger than for any other material... |
| CO2 | carbon dioxide Carbon dioxide Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom... |
| CO | carbon monoxide Carbon monoxide Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal... |
| CPOX | catalytic partial oxidation |
| CPS | continuous power supply |
| DBFC | direct borohydride fuel cell Direct borohydride fuel cell Direct borohydride fuel cells are a subcategory of alkaline fuel cells which are directly fed by sodium borohydride or potassium borohydride as a fuel and either air/oxygen or hydrogen peroxide as the oxidant... |
| DC | direct current Direct current Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through... |
| DCFC | direct carbon fuel cell Direct carbon fuel cell A Direct Carbon Fuel Cell is a fuel cell that uses a carbon rich material as a fuel. The cell produces energy by combining carbon and oxygen, which releases carbon dioxide as a by-product.The total reaction of the cell is C + O2 → CO2.... |
| DEFC | direct-ethanol fuel cell Direct-ethanol fuel cell Direct-ethanol fuel cells or DEFCs are a subcategory of Proton-exchange fuel cells where the fuel, ethanol, is fed directly to the fuel cell.-Advantages:... |
| DER | distributed energy resource |
| DFAFC | formic acid fuel cell Formic acid fuel cell Direct-formic acid fuel cells or DFAFCs are a subcategory of proton exchange membrane fuel cells where, the fuel, formic acid, is not reformed, but fed directly to the fuel cell... |
| DMFC | direct methanol fuel cell |
| E0 | standard electrode potential Standard electrode potential In electrochemistry, the standard electrode potential, abbreviated E° or E , is the measure of individual potential of a reversible electrode at standard state, which is with solutes at an effective concentration of 1 mol dm−3, and gases at a pressure of 1 atm... |
| EBOP | electrical balance of plant |
| EGFC | electro-galvanic fuel cell Electro-galvanic fuel cell An electro-galvanic fuel cell is an electrical device, one form of which is commonly used to measure the concentration of oxygen gas in scuba diving and medical equipment.... |
| EOF | electroosmotic flow |
| EOP | electroosmotic pump Electroosmotic pump An electroosmotic pump , or EO pump, is used for generating flow or pressure by use of an electric field. One application of this is removing liquid flooding water from channels and gas diffusion layers and direct hydration of the proton exchange membrane in the membrane electrode assembly of the... |
| °F | fahrenheit Fahrenheit Fahrenheit is the temperature scale proposed in 1724 by, and named after, the German physicist Daniel Gabriel Fahrenheit . Within this scale, the freezing of water into ice is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees... |
| FB | flow battery Flow battery A flow battery is a form of rechargeable battery in which electrolyte containing one or more dissolved electroactive species flows through an electrochemical cell that converts chemical energy directly to electricity... |
| FC | fuel cell Fuel cell A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used... |
| FGD | flue gas desulfurization Flue gas desulfurization Sulfur dioxide is one of the elements forming acid rain. Tall flue-gas stacks disperse emissions by diluting the pollutants in ambient air and transporting them to other regions.... |
| FMEA | failure mode and effects analysis Failure mode and effects analysis A failure modes and effects analysis is a procedure in product development and operations management for analysis of potential failure modes within a system for classification by the severity and likelihood of the failures... |
| FPS | fuel processing system |
| GDC | gadolinium Gadolinium Gadolinium is a chemical element with the symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined form. Gadolinium was first detected spectroscopically in 1880 by de Marignac who separated its oxide and is credited with... doped ceria |
| GEG | gasoline-equivalent gallon |
| GGE | gasoline gallon equivalent |
| H2 | hydrogen Hydrogen Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly... |
| H2O | water Water Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a... |
| HC | hydrocarbon Hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls.... |
| HCDP | hydrocarbon dew point Hydrocarbon dew point The hydrocarbon dew point is the temperature at which the hydrocarbon components of any hydrocarbon-rich gas mixture, such as natural gas, will start to condense out of the gaseous phase. It is often also referred to as the HDP or the HCDP. The maximum temperature at which such condensation takes... |
| HCOOH | formic acid Formic acid Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early... |
| HDP | hydrocarbon dew point Hydrocarbon dew point The hydrocarbon dew point is the temperature at which the hydrocarbon components of any hydrocarbon-rich gas mixture, such as natural gas, will start to condense out of the gaseous phase. It is often also referred to as the HDP or the HCDP. The maximum temperature at which such condensation takes... |
| HDS | hydrodesulfurization Hydrodesulfurization Hydrodesulfurization is a catalytic chemical process widely used to remove sulfur from natural gas and from refined petroleum products such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils... |
| HEV | hybrid electric vehicle Hybrid electric vehicle A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional... |
| HHV | higher heating value |
| HTS | high temperature shift |
| ICE | internal combustion engine Internal combustion engine The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine... |
| IMFC | indirect methanol fuel cell |
| KG | kilogram Kilogram The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water... |
| KOH | potassium hydroxide Potassium hydroxide Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive... |
| kW | kilowatt |
| kWh | kilowatt hour |
| kW/kg | Kilowatts per kilogram Kilogram The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water... |
| kW/m3 | Kilowatts per cubic meter |
| kW/sq.m | Kilowatts per square meter |
| LCA | life cycle assessment Life cycle assessment A life-cycle assessment is a technique to assess environmental impacts associated with all the stages of a product's life from-cradle-to-grave A life-cycle assessment (LCA, also known as life-cycle analysis, ecobalance, and cradle-to-grave analysis) is a technique to assess environmental impacts... |
| LDH | layered double hydroxide |
| LEL | lower explosive limit |
| LFG | landfill gas Landfill gas Landfill gas is a complex mix of different gases created by the action of microorganisms within a landfill.-Production:Landfill gas production results from chemical reactions and microbes acting upon the waste as the putrescible materials begins to break down in the landfill... |
| LFL | lower flammable limit Lower flammable limit Lower flammability limit , usually expressed in volume per cent, is the lower end of the concentration range of a flammable solvent at a given temperature and pressure for which air/vapor mixtures can ignite. The flammability range is delineated by the upper and lower flammability limit. Outside... |
| LH2 | liquid hydrogen Liquid hydrogen Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be... |
| LHV | lower heating value |
| LNG | liquefied natural gas Liquefied natural gas Liquefied natural gas or LNG is natural gas that has been converted temporarily to liquid form for ease of storage or transport.... |
| LOD | limit of detection |
| LPG | liquefied petroleum gas |
| LSM | lanthanum strontium manganite Lanthanum strontium manganite Lanthanum strontium manganite is an oxide ceramic material with the general formula La1-xSrxMnO3, where x describes the doping level and is usually in the range of 10-20%.... |
| LTS | low temperature shift |
| MAF | mass flow sensor Mass flow sensor A mass air flow sensor is used to find out the mass flowrate of air entering a fuel-injected internal combustion engine. The air mass information is necessary for the engine control unit to balance and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts... |
| MAOP | maximum allowable operating pressure Maximum allowable operating pressure Maximum allowable operating pressure or MAOP refers to the wall strength of a pressurized cylinder such as a pipeline or storage tank and how much pressure the walls may safely hold in normal operation.... |
| MBOP | mechanical balance of plant |
| MCFC | molten-carbonate fuel cell Molten-carbonate fuel cell Molten-carbonate fuel cells are high-temperature fuel cells, that operate at temperatures of 600°C and above.Molten carbonate fuel cells are currently being developed for natural gas, biogas , and coal-based power plants for electrical utility, industrial, and military applications... |
| mCHP | micro combined heat and power |
| MDT | mean down time Mean down time In organizational management, mean down time is the average time that a system is non-operational. This includes all time associated with repair, corrective and preventive maintenance, self imposed downtime, and any logistics or administrative delays... |
| MEA | membrane electrode assembly Membrane electrode assembly A membrane electrode assembly is an assembled stack of proton exchange membranes or alkali anion exchange membrane , catalyst and flat plate electrode used in a fuel cell.-PEM-MEA:... |
| MeOH | methanol Methanol Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol... |
| MFC | microbial fuel cell Microbial fuel cell A microbial fuel cell or biological fuel cell is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature.... |
| mm | millimeter |
| MPGe | miles per gallon of gasoline equivalent |
| MRO | maintenance, repair and operations Maintenance, Repair and Operations Maintenance, repair, and operations or maintenance, repair, and overhaul involves fixing any sort of mechanical or electrical device should it become out of order or broken... |
| MSR | methanol steam reforming |
| MTBF | mean time between failures |
| MTBO | mean time between outages |
| MW | megawatt |
| mW | milliwatt |
| N2 | nitrogen Nitrogen Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere... |
| NEG | net energy gain Net energy gain Net Energy Gain is a concept used in energy economics that refers to the difference between the energy expended to harvest an energy source and the amount of energy gained from that harvest. The net energy gain, which can be expressed in joules, differs from the net financial gain that may result... |
| NOx | nitrogen oxide Nitrogen oxide Nitrogen oxide can refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:* Nitric oxide, also known as nitrogen monoxide, , nitrogen oxide* Nitrogen dioxide , nitrogen oxide... |
| O | oxygen Oxygen Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition... |
| OCV | open-circuit voltage Open-circuit voltage Open-circuit voltage is the difference of electrical potential between two terminals of a device when there is no external load connected, i.e. the circuit is broken or open. Under these conditions there is no external electric current between the terminals, even though there may be current... |
| OEM | original equipment manufacturer Original Equipment Manufacturer An original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a... |
| Pa | pascal Pascal (unit) The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre... |
| PAFC | phosphoric acid fuel cell |
| PBI | polybenzimidazole fiber |
| PCFC | protonic ceramic fuel cell Protonic ceramic fuel cell The Protonic ceramic fuel cell or PCFC is a fuel cell based on a ceramic electrolyte material that exhibits high protonic conductivity at elevated temperatures.... |
| Pd | palladium Palladium Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired... |
| p.d. | potential difference |
| PEC | photoelectrochemical cell Photoelectrochemical cell Photoelectrochemical cells or PECs are solar cells which generate electrical energy from light, including visible light. Some photoelectrochemical cells simply produce electrical energy, while others produce hydrogen in a process similar to the electrolysis of water.-Photogeneration cell:In this... |
| PEDOT | poly(3,4-ethylenedioxythiophene) Poly(3,4-ethylenedioxythiophene) Poly or PEDOT is a conducting polymer based on 3,4-ethylenedioxylthiophene or EDOT monomer. Advantages of this polymer are optical transparency in its conducting state, high stability and moderate band gap and low redox potential... |
| PEDT | poly(3,4-ethylenedioxythiophene) Poly(3,4-ethylenedioxythiophene) Poly or PEDOT is a conducting polymer based on 3,4-ethylenedioxylthiophene or EDOT monomer. Advantages of this polymer are optical transparency in its conducting state, high stability and moderate band gap and low redox potential... |
| PEFC | polymer electrolyte membrane fuel cell |
| PEM | polymer electrolyte membrane or proton exchange membrane Proton exchange membrane A proton exchange membrane or polymer electrolyte membrane is a semipermeable membrane generally made from ionomers and designed to conduct protons while being impermeable to gases such as oxygen or hydrogen... |
| PEMFC | polymer electrolyte membrane fuel cell or proton exchange membrane fuel cell Proton exchange membrane fuel cell Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells , are a type of fuel cell being developed for transport applications as well as for stationary fuel cell applications and portable fuel cell applications. Their distinguishing features include lower... |
| PM | particulate matter |
| POX | partial oxidation Partial oxidation Partial oxidation is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell... |
| ppm | parts per million |
| ppmv | parts per million volume |
| PROX | preferential oxidation |
| PRV | pressure relief valve |
| PSA | pressure swing adsorption Pressure swing adsorption Pressure swing adsorption is a technology used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an adsorbent material. It operates at near-ambient temperatures and so differs from cryogenic distillation... |
| PSU | power supply Power supply A power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy... unit |
| Pt | platinum Platinum Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal... |
| PTFE | polytetrafluoroethylene Polytetrafluoroethylene Polytetrafluoroethylene is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. PTFE is most well known by the DuPont brand name Teflon.... |
| Pv | power density Power density Power density is the amount of power per unit volume.... |
| Re | reynolds number |
| RESS | rechargeable energy storage system Rechargeable energy storage system A rechargeable energy storage system or RESS is a system that stores energy for delivery of power and which is rechargeable.Production storage systems use electric rechargeable traction batteries, electric double-layer capacitors or flywheel energy storage.This term of art is used in US legislation... |
| RFC | reversible fuel cell Reversible fuel cell A regenerative fuel cell or reverse fuel cell is a fuel cell run in reverse mode, which consumes electricity and chemical B to produce chemical A. By definition, the process of any fuel cell could be reversed. However, a given device is usually optimized for operating in one mode and may not be... |
| RMFC | reformed methanol fuel cell Reformed methanol fuel cell Reformed Methanol Fuel Cell or Indirect Methanol Fuel Cell systems are a subcategory of proton-exchange fuel cells where, the fuel, methanol , is reformed, before being fed into the fuel cell... |
| s/c | short circuit Short circuit A short circuit in an electrical circuit that allows a current to travel along an unintended path, often where essentially no electrical impedance is encountered.... or steam to carbon ratio |
| SFC | standard cubic foot Standard cubic foot A standard cubic foot is a measure of quantity of gas, equal to a cubic foot of volume at 60 degrees Fahrenheit and either 14.696 psi or 14.73 psi of pressure.A standard cubic foot is thus not a unit of volume but of quantity, and the conversion to normal cubic metres is... or sometimes solid oxide fuel cell |
| SMPS | switched-mode power supply Switched-mode power supply A switched-mode power supply is an electronic power supply that incorporates a switching regulator in order to be highly efficient in the conversion of electrical power... |
| SMR | steam reforming Steam reforming Fossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to... |
| SOEC | solid oxide electrolyser cell Solid oxide electrolyser cell A solid oxide electrolyzer cell is a solid oxide fuel cell that is run in regenerative mode to achieve the electrolysis of water and which uses a solid oxide, or ceramic, electrolyte to produce oxygen and hydrogen gas.-Principle:... |
| SOFC | solid oxide fuel cell |
| SR | steam reforming Steam reforming Fossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to... |
| TA | technology assessment Technology assessment Technology assessment Technology assessment Technology assessment (TA, German Tenteractive, and communicative process that aims to contribute to the formation of public and political opinion on societal aspects of science and technology.- General description :... |
| TGC | tail-gas combustor |
| TOF | turnover frequency |
| TPB | triple-phase boundary |
| TPE | thermoplastic elastomers |
| TPOX | thermal partial oxidation Partial oxidation Partial oxidation is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell... |
| TRL | technology readiness level Technology Readiness Level Technology Readiness Level is a measure used by some United States government agencies and many of the world's major companies to assess the maturity of evolving technologies prior to incorporating that technology into a system or subsystem... |
| UEL | upper explosive limit |
| UPS | uninterruptible power supply Uninterruptible power supply An uninterruptible power supply, also uninterruptible power source, UPS or battery/flywheel backup, is an electrical apparatus that provides emergency power to a load when the input power source, typically mains power, fails... |
| URFC | unitized regenerative fuel cell Unitized regenerative fuel cell A unitized regenerative fuel cell is a fuel cell based on the proton exchange membrane which can do the electrolysis of water in regenerative mode and function in the other mode as a fuel cell recombining oxygen and hydrogen gas to produce electricity. Both modes are done with the same fuel cell... |
| VHC | volumetric heat capacity Volumetric heat capacity Volumetric heat capacity , also termed volume-specific heat capacity, describes the ability of a given volume of a substance to store internal energy while undergoing a given temperature change, but without undergoing a phase change... |
| VLE | vapor–liquid equilibrium |
| W | watt Watt The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:... |
| WGS | water–gas shift reaction |
| Wt.% | weight percent |
| YSZ | yttria-stabilized zirconia Yttria-stabilized zirconia Yttria-stabilized zirconia is a zirconium-oxide based ceramic, in which the particular crystal structure of zirconium oxide is made stable at room temperature by an addition of yttrium oxide... |
| ZnO | zinc oxide Zinc oxide Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,... |