David Enskog
Encyclopedia
David Enskog was a Swedish
mathematical physicist
. Enskog helped develop the kinetic theory of gases by extending the Maxwell–Boltzmann equations
.
he received a licentiate
degree in physics in 1911, working on gas diffusion
under professor Gustaf Granqvist, who was an experimentalist. Enskog did not wish to continue with experimental physics, however, and transferred to professor Carl Wilhelm Oseen
for his Ph.D.
From 1913, Enskog worked as a high school teacher in mathematics and physics to support himself and his family, while continuing his research and thesis writing in his free time. In 1917 he completed his thesis on kinetic theory of gases at Uppsala. As his thesis was considered obscure and difficult to grasp, he received a rather mediocre grade on it, which did not qualify him to become a docent
, which was the essential next step in a Swedish academic career.
Enskog therefore continued to work as a high school teacher, but contacted Sydney Chapman, who had worked on the same problems as Enskog. Already in 1917, Chapman recognised the importance of Enskog's work. In the 1920s Enskog's contributions to the kinetic theory of gases became more recognised. In 1929, Enskog tried to make a comeback into the academic world by applying for two professorships in Stockholm
, one in mechanics and mathematical physics at Stockholm University College
and one in mathematics and mechanics at the Royal Institute of Technology
(KTH). Enskog did not get the professorship at the University College, and the selection committee at KTH was divided and leaning towards Hilding Faxén
until Chapman, on a visit to Sweden, voiced strong support for Enskog and wrote a letter of recommendation on his behalf. Finally, Enskog was appointed professor at KTH on December 12, 1930. As a KTH professor, Enskog mainly got caught up in teaching duties, and did not do much further research.
The fusion of Chapman's and Enskog's theories later became known as the Chapman–Enskog method for solving the Boltzmann equation. In a 1939 book called The Mathematical Theory of Non-Uniform Gases, written by Chapman and Thomas Cowley and dedicated to David Enskog, the authors expanded this theory under the Chapman-Enskog designation.
Further recognition of Enskog's work came in 1945, when the Smyth Report
on the US atomic weapons project was published. Chapman and Enskog were metioned as the discoverers of thermal diffusion
, which was one of the methods used to enrich
uranium
235 for the first nuclear weapons. Enskog was the only Swedish scientist mentioned in this report.
Enskog was elected to the Royal Swedish Academy of Engineering Sciences
in 1941, and finally to the Royal Swedish Academy of Sciences
on May 28, 1947, only days before his death.
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
mathematical physicist
Mathematical physics
Mathematical physics refers to development of mathematical methods for application to problems in physics. The Journal of Mathematical Physics defines this area as: "the application of mathematics to problems in physics and the development of mathematical methods suitable for such applications and...
. Enskog helped develop the kinetic theory of gases by extending the Maxwell–Boltzmann equations
Maxwell–Boltzmann statistics
In statistical mechanics, Maxwell–Boltzmann statistics describes the statistical distribution of material particles over various energy states in thermal equilibrium, when the temperature is high enough and density is low enough to render quantum effects negligible.The expected number of particles...
.
Biography
After undergraduate studies at Uppsala UniversityUppsala University
Uppsala University is a research university in Uppsala, Sweden, and is the oldest university in Scandinavia, founded in 1477. It consistently ranks among the best universities in Northern Europe in international rankings and is generally considered one of the most prestigious institutions of...
he received a licentiate
Licentiate
Licentiate is the title of a person who holds an academic degree called a licence. The term may derive from the Latin licentia docendi, meaning permission to teach. The term may also derive from the Latin licentia ad practicandum, which signified someone who held a certificate of competence to...
degree in physics in 1911, working on gas diffusion
Diffusion
Molecular 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...
under professor Gustaf Granqvist, who was an experimentalist. Enskog did not wish to continue with experimental physics, however, and transferred to professor Carl Wilhelm Oseen
Carl Wilhelm Oseen
Carl Wilhelm Oseen was a theoretical physicist in Uppsala and Director of the Nobel Institute for Theoretical Physics in Stockholm....
for his Ph.D.
Ph.D.
A Ph.D. is a Doctor of Philosophy, an academic degree.Ph.D. may also refer to:* Ph.D. , a 1980s British group*Piled Higher and Deeper, a web comic strip*PhD: Phantasy Degree, a Korean comic series* PhD Docbook renderer, an XML renderer...
From 1913, Enskog worked as a high school teacher in mathematics and physics to support himself and his family, while continuing his research and thesis writing in his free time. In 1917 he completed his thesis on kinetic theory of gases at Uppsala. As his thesis was considered obscure and difficult to grasp, he received a rather mediocre grade on it, which did not qualify him to become a docent
Docent
Docent is a title at some European universities to denote a specific academic appointment within a set structure of academic ranks below professor . Docent is also used at some universities generically for a person who has the right to teach...
, which was the essential next step in a Swedish academic career.
Enskog therefore continued to work as a high school teacher, but contacted Sydney Chapman, who had worked on the same problems as Enskog. Already in 1917, Chapman recognised the importance of Enskog's work. In the 1920s Enskog's contributions to the kinetic theory of gases became more recognised. In 1929, Enskog tried to make a comeback into the academic world by applying for two professorships in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
, one in mechanics and mathematical physics at Stockholm University College
Stockholm University
Stockholm University is a state university in Stockholm, Sweden. It has over 28,000 students at four faculties, making it one of the largest universities in Scandinavia. The institution is also frequently regarded as one of the top 100 universities in the world...
and one in mathematics and mechanics at the Royal Institute of Technology
Royal Institute of Technology
The Royal Institute of Technology is a university in Stockholm, Sweden. KTH was founded in 1827 as Sweden's first polytechnic and is one of Scandinavia's largest institutions of higher education in technology. KTH accounts for one-third of Sweden’s technical research and engineering education...
(KTH). Enskog did not get the professorship at the University College, and the selection committee at KTH was divided and leaning towards Hilding Faxén
Hilding Faxén
Olov Hilding Faxén was a Swedish physicist who was primarily active within mechanics.Faxén received his doctorate in 1921 at Uppsala University with the thesis Einwirkung der Gefässwände auf den Widerstand gegen die Bewegung einer kleinen Kugel in einer zähen Flüssigkeit Olov Hilding Faxén (March...
until Chapman, on a visit to Sweden, voiced strong support for Enskog and wrote a letter of recommendation on his behalf. Finally, Enskog was appointed professor at KTH on December 12, 1930. As a KTH professor, Enskog mainly got caught up in teaching duties, and did not do much further research.
The fusion of Chapman's and Enskog's theories later became known as the Chapman–Enskog method for solving the Boltzmann equation. In a 1939 book called The Mathematical Theory of Non-Uniform Gases, written by Chapman and Thomas Cowley and dedicated to David Enskog, the authors expanded this theory under the Chapman-Enskog designation.
Further recognition of Enskog's work came in 1945, when the Smyth Report
Smyth Report
The Smyth Report was the common name given to an administrative history written by physicist Henry DeWolf Smyth about the Allied World War II effort to develop the atomic bomb, the Manhattan Project...
on the US atomic weapons project was published. Chapman and Enskog were metioned as the discoverers of thermal diffusion
Thermal diffusion
Thermal diffusion may refer to:* Thermal diffusion, an obsolete method of uranium enrichment* Brownian motion .* Diffusion in a temperature gradient ....
, which was one of the methods used to enrich
Enrichment
Enrichment may mean:*Education. *The process of adding nutrients to cereals or grain: see food fortification.*The process of adding sugar to grape must during winemaking in order to achieve a higher alcohol content of the wine, more commonly referred to as chaptalization.*Behavioral...
uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
235 for the first nuclear weapons. Enskog was the only Swedish scientist mentioned in this report.
Enskog was elected to the Royal Swedish Academy of Engineering Sciences
Royal Swedish Academy of Engineering Sciences
The Royal Swedish Academy of Engineering Sciences or Kungl. Ingenjörsvetenskapsakademien , founded in 1919 by King Gustaf V, is one of the Royal Academies in Sweden...
in 1941, and finally to the Royal Swedish Academy of Sciences
Royal Swedish Academy of Sciences
The Royal Swedish Academy of Sciences or Kungliga Vetenskapsakademien is one of the Royal Academies of Sweden. The Academy is an independent, non-governmental scientific organization which acts to promote the sciences, primarily the natural sciences and mathematics.The Academy was founded on 2...
on May 28, 1947, only days before his death.