Rudolf Julius Emanuel Clausius (Clausius Rudolf Julius Emanuel)( German physicist.)
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Biography Rudolf Julius Emanuel Clausius (Clausius Rudolf Julius Emanuel)
Born January 2, 1822 in Kesline (now Koszalin, Poland) in the family pastor. He studied at a private school, then in high school. He graduated from the University of Berlin (1848), where he received his Ph.D.. In 1850-1857 he taught in Berlin and Zurich. Professor universities in Zurich, Wц+rzburg, Bonn. Since 1884 - rector of the University of Bonn.
The main work of Clausius cover the basics of thermodynamics and kinetic theory of gases. He first gave a rigorous formulation of the principle of equivalence of heat and work. In 1850, regardless of W. Rankin was the ratio between these values (the first law of thermodynamics), and developed the ideal thermodynamic cycle of the steam engine (Rankine cycle - Clausius). In the same year (along with W. Thomson) gave the first formulation of the second law of thermodynamics: "Heat can not of itself move from a colder body to a warmer '. In 1865 introduced the concept of entropy, . found its most important property: in a closed system, entropy is either constant (reversible process), . or increases (irreversible), . thus showing, . that the change in entropy determines the direction of, . in which the process takes place,
. Suggested 'heat death' of the universe, extending to it the principle of entropy. The fallacy of this idea proved subsequently Boltzmann.
Clausius made a great contribution to the development of molecular-kinetic theory of gases. He first applied this new approach - the so-called method of averages (what is now called the statistical methods), explained with a unified voice such diverse phenomena as internal friction, thermal conductivity, diffusion. Introduced the concept of mean free path of molecules and in 1860 its calculated value, which further allowed us to estimate the size of molecules. Generalized equation of gas state Van der Waals forces, revealed the meaning of the equation, which relates the melting point (or boiling) of a substance with pressure (equation of Clapeyron - Clausius).
In addition, Clausius developed the theory of dielectric polarization, from which, regardless of OS Mossotti derived the relationship between permittivity and polarizability (Clausius - Mossotti).
Died Clausius at Bonn August 24, 1888.