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
Enthalpy older term "heat content", a term which is now mostly deprecated as misleading, as refers to the amount of heat absorbed in a process at constant pressure only, but not in the general case (when pressure is variable). Josiah Willard Gibbs used the term "a heat function for constant pressure" for clarity. Introduction of the concept of "heat content" is associated with Benoît Paul Émile Clapeyron and Rudolf Clausius (Clausius–Clapeyron relation, 1850). The term "enthalpy" first appeared in print in 1909. It is attributed to Heike Kamerlingh Onnes, who most likely introduced it orally the year before, at the first