Mass flow
Encyclopedia
Mass flow, also known as mass transfer
and bulk flow, is the movement of material matter. In physics, mass flow occurs in open systems and is often measured as occurring when moving across a certain boundary characterized by its cross-sectional area and a flow rate
. In engineering and biology it may also be a flow of fluids in a tube or vessel of a certain diameter. A bulk transfer of particles of matter in a characterised type of flow is also known as bulk flow
Examples include, blood circulation, transport of water
in xylem
vessels and phloem
tubes of plants. This relies upon the cohesion of water molecules to each other and adhesion to the vessel's wall via hydrogen bonding. If an air bubble forms the flow will be stopped as the column is broken and the pressure difference in the vessel cannot be transmitted; this is called an embolism. Once these embolisms are nucleated, the remaining water in the capillaries begins to turn to water vapor. Plants have physiological mechanisms to reestablish the capillary action within their cells. The "snapping" can be heard, and this sound can be used to measure the rate of cavitation
within a plant.
Mass transfer
Mass 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 bulk flow, is the movement of material matter. In physics, mass flow occurs in open systems and is often measured as occurring when moving across a certain boundary characterized by its cross-sectional area and a flow rate
Mass flow rate
Mass flow rate is the mass of substance which passes through a given surface per unit time. Its unit is mass divided by time, so kilogram per second in SI units, and slug per second or pound per second in US customary units...
. In engineering and biology it may also be a flow of fluids in a tube or vessel of a certain diameter. A bulk transfer of particles of matter in a characterised type of flow is also known as bulk flow
Examples include, blood circulation, transport of 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...
in xylem
Xylem
Xylem is one of the two types of transport tissue in vascular plants. . The word xylem is derived from the Classical Greek word ξυλον , meaning "wood"; the best-known xylem tissue is wood, though it is found throughout the plant...
vessels and phloem
Phloem
In vascular plants, phloem is the living tissue that carries organic nutrients , in particular, glucose, a sugar, to all parts of the plant where needed. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Greek word "bark"...
tubes of plants. This relies upon the cohesion of water molecules to each other and adhesion to the vessel's wall via hydrogen bonding. If an air bubble forms the flow will be stopped as the column is broken and the pressure difference in the vessel cannot be transmitted; this is called an embolism. Once these embolisms are nucleated, the remaining water in the capillaries begins to turn to water vapor. Plants have physiological mechanisms to reestablish the capillary action within their cells. The "snapping" can be heard, and this sound can be used to measure the rate of cavitation
Cavitation
Cavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...
within a plant.