Sabba S. Stefanescu
Encyclopedia
Sabba S. Ştefănescu was a Romania
n geophysicist, professor of geophysics
, member of the Romanian Academy
. He was the cofounder, together with Liviu Constantinescu
, of the Romanian school of geophysics
.
, and of his wife Constanţa. He received at first a private education, then visited for a couple of years the college St Sava in Bucharest
, but left the country together with his family in 1917 for Paris, where his father had to accomplish a diplomatic mission. He obtained there his baccalauréat
at the Lycée Saint-Louis
and was admitted as a student at the prestigious École des Mines
, from which he graduated in 1923. He returned subsequently to Romania, where he worked for some time in the mining district of the Jiu Valley
. In 1927 he joined the Geological Institute of Romania, where he began his studies in electrical prospecting, which was to remain his lifelong preoccupation.
Two short papers of his drew the attention of the brothers Conrad
and Marcel Schlumberger
. They were at that time the pioneers of this field in Europe and had just founded the geophysical prospecting
company bearing their name, which has developed since into the world leading Schlumberger Limited. Ştefănescu entered into a direct collaboration with them and spent the years 1929-1933 in Paris, a period which he considered to be the most fruitful of his scientific life. He returned to Romania in 1933 and resumed his work at the Geological Institute, being at the same time a consulting engineer of the Schlumberger company.
He received a doctor's degree in physics
from the University of Bucharest (1945), was elected a corresponding member of the Romanian Academy (1946) and became head of the geophysical department of the Geological Committee (1950) and of a new Department of Geophysics at the Institute for Mining in Bucharest (subsequently transferred to the Institute for Oil, Gas and Geology); he retained these positions until his retirement in 1967. One may say that over that period the first generations of Romanian geophysicists were formed; he made an essential contribution to this. He was elected a full member of the Romanian Academy (1963) and president of its Section of Geological, Geophysical and Geographical Sciences (1966-1990). He was the director of several institutes of geophysics belonging to the Romanian Academy or to the Geological Committee, and was (until 1990) editor of the journal Revue roumaine de géologie, géophysique et géographie and president of the Romanian National Committee of Geodesy and Geophysics. He received in 1990 the honorary membership of the Society of Exploration Geophysicists
“for developing the theoretical basis for several methods now in common use”.
The midpoint of his scientific activity was the theory of electrical prospecting in geophysics. He was one of the first to perform a complete calculation in a realistic context (1930) of the electromagnetic field generated by a prospecting device and thus of the apparent resistivity of the ground. A series of subsequent papers (1930-1950) offered a detailed analysis of the usual DC and AC electrical prospecting methods. Later on he developed the theory of alpha media which allows an easy calculation of the electric field within a large family of models for the conductivity of the ground and facilitates the interpretation of the measured data. Another problem originating in electrical prospecting and to which he devoted for a long time his mathematical abilities was the determination of the magnetic field lines for various configurations of currents. He developed a special geometrical intuition which allowed him to integrate the complicated differential equations of the field lines of linear currents with increasingly complex arrangements. In this context he could produce explicit examples of open magnetic field lines.
To those who knew him, he was an amiable and reserved person, with a pleasant and distinguished conversation. He regarded an optimistic attitude of mind as a duty and conveyed his serene outlook to those surrounding him. He had a steady and intense curiosity in intellectual matters, including philosophy and arts. The clarity of his scientific discourse was impressive.
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
n geophysicist, professor of geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
, member of the Romanian Academy
Romanian Academy
The Romanian Academy is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 acting members who are elected for life....
. He was the cofounder, together with Liviu Constantinescu
Liviu Constantinescu
Liviu Constantinescu was a Romanian geophysicist, professor of geophysics, member of the Romanian Academy. He was the cofounder, together with Sabba S...
, of the Romanian school of geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
.
Biography
He was the third and youngest son of Sabba Ştefănescu, professor of paleontology at the University of BucharestUniversity of Bucharest
The University of Bucharest , in Romania, is a university founded in 1864 by decree of Prince Alexander John Cuza to convert the former Saint Sava Academy into the current University of Bucharest.-Presentation:...
, and of his wife Constanţa. He received at first a private education, then visited for a couple of years the college St Sava in Bucharest
Bucharest
Bucharest is the capital municipality, cultural, industrial, and financial centre of Romania. It is the largest city in Romania, located in the southeast of the country, at , and lies on the banks of the Dâmbovița River....
, but left the country together with his family in 1917 for Paris, where his father had to accomplish a diplomatic mission. He obtained there his baccalauréat
Baccalauréat
The baccalauréat , often known in France colloquially as le bac, is an academic qualification which French and international students take at the end of the lycée . It was introduced by Napoleon I in 1808. It is the main diploma required to pursue university studies...
at the Lycée Saint-Louis
Lycée Saint-Louis
The lycée Saint-Louis is a higher education establishment located in the VIe arrondissement of Paris, in the Latin Quarter. It is the only public French lycée exclusively dedicated to classes préparatoires aux grandes écoles...
and was admitted as a student at the prestigious École des Mines
École nationale supérieure des mines de Paris
The École Nationale Supérieure des Mines de Paris was created in 1783 by King Louis XVI in order to train intelligent directors of mines. It is one of the most prominent French engineering schoolsThe École Nationale Supérieure des Mines de Paris (also known as Mines ParisTech, École des Mines de...
, from which he graduated in 1923. He returned subsequently to Romania, where he worked for some time in the mining district of the Jiu Valley
Jiu Valley
The Jiu Valley is a region in southwestern Romania, in Hunedoara county, situated in a valley of the Jiu River between the Retezat Mountains and the Parâng Mountains...
. In 1927 he joined the Geological Institute of Romania, where he began his studies in electrical prospecting, which was to remain his lifelong preoccupation.
Two short papers of his drew the attention of the brothers Conrad
Schlumberger brothers
Conrad Schlumberger and Marcel Schlumberger were brothers from the Alsace region in France...
and Marcel Schlumberger
Schlumberger brothers
Conrad Schlumberger and Marcel Schlumberger were brothers from the Alsace region in France...
. They were at that time the pioneers of this field in Europe and had just founded the geophysical prospecting
Exploration geophysics
Exploration geophysics is the applied branch of geophysics which uses surface methods to measure the physical properties of the subsurface Earth, in order to detect or infer the presence and position of ore minerals, hydrocarbons, geothermal reservoirs, groundwater reservoirs, and other geological...
company bearing their name, which has developed since into the world leading Schlumberger Limited. Ştefănescu entered into a direct collaboration with them and spent the years 1929-1933 in Paris, a period which he considered to be the most fruitful of his scientific life. He returned to Romania in 1933 and resumed his work at the Geological Institute, being at the same time a consulting engineer of the Schlumberger company.
He received a doctor's degree in physics
Physics
Physics 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...
from the University of Bucharest (1945), was elected a corresponding member of the Romanian Academy (1946) and became head of the geophysical department of the Geological Committee (1950) and of a new Department of Geophysics at the Institute for Mining in Bucharest (subsequently transferred to the Institute for Oil, Gas and Geology); he retained these positions until his retirement in 1967. One may say that over that period the first generations of Romanian geophysicists were formed; he made an essential contribution to this. He was elected a full member of the Romanian Academy (1963) and president of its Section of Geological, Geophysical and Geographical Sciences (1966-1990). He was the director of several institutes of geophysics belonging to the Romanian Academy or to the Geological Committee, and was (until 1990) editor of the journal Revue roumaine de géologie, géophysique et géographie and president of the Romanian National Committee of Geodesy and Geophysics. He received in 1990 the honorary membership of the Society of Exploration Geophysicists
Society of Exploration Geophysicists
The Society of Exploration Geophysicists is a nonprofit organization dedicated to promoting the science of geophysics and the education of exploration geophysicists. The Society fosters the expert and ethical practice of geophysics in the exploration and development of natural resources, in...
“for developing the theoretical basis for several methods now in common use”.
The midpoint of his scientific activity was the theory of electrical prospecting in geophysics. He was one of the first to perform a complete calculation in a realistic context (1930) of the electromagnetic field generated by a prospecting device and thus of the apparent resistivity of the ground. A series of subsequent papers (1930-1950) offered a detailed analysis of the usual DC and AC electrical prospecting methods. Later on he developed the theory of alpha media which allows an easy calculation of the electric field within a large family of models for the conductivity of the ground and facilitates the interpretation of the measured data. Another problem originating in electrical prospecting and to which he devoted for a long time his mathematical abilities was the determination of the magnetic field lines for various configurations of currents. He developed a special geometrical intuition which allowed him to integrate the complicated differential equations of the field lines of linear currents with increasingly complex arrangements. In this context he could produce explicit examples of open magnetic field lines.
To those who knew him, he was an amiable and reserved person, with a pleasant and distinguished conversation. He regarded an optimistic attitude of mind as a duty and conveyed his serene outlook to those surrounding him. He had a steady and intense curiosity in intellectual matters, including philosophy and arts. The clarity of his scientific discourse was impressive.