Gerardus J. Sizoo Gerardus J. Sizoo Gerardus Johannes Sizoo (8 November 1900 – 4 January 1994) was the first professor of physics at the Vrije Universiteit. He is notable for the establishment and development of the applied physics laboratory in 1930 and the establishment of the Faculty of Mathematics and Physics at the Vrije Universiteit. His doctoral research explored the phenomenon of superconductivity at the University of Leiden, following the lead of Heike Kamerlingh Onnes and Wander Johannes de Haas. He completed his PhD in 1926, with a thesis entitled: "Onderzoekingen over den suprageleidenden toestand van metalen," under Wander Johannes de Haas. In
Liquefaction of gases textiles and manufacture of carbon tetrachloride, glycol and numerous other organic compounds as well as phosgene gas. Liquefaction of helium (He) with the precooled Hampson–Linde cycle led to a Nobel Prize for Heike Kamerlingh Onnes in 1913. At ambient pressure the boiling point of liquefied helium is . Below 2.17 K liquid He becomes a superfluid (Nobel Prize 1978, Pyotr Kapitsa) and shows characteristic properties such as heat conduction through second sound, zero viscosity and the fountain effect among others. The liquefaction of gases is a complicated process that uses various compressions and expansions to achieve high pressures and very