Clausius’ Disgregation: A Conceptual Relic that Sheds Light on the Second Law

Abstract

Abstract:The present work analyzes the cognitive process that led Clausius towards the translation of the Second Law of Thermodynamics into mathematical expressions. We show that Clausius' original formal expression of the Second Law was achieved by making extensive use of the concept of disgregation, a quantity which has subsequently disappeared from the thermodynamic language. Our analysis demonstrates that disgregation stands as a crucial logical step of such process and sheds light on the comprehension of such fundamental relation. The introduction of entropy-which occurred three years after the first formalization of the Second Law-was aimed at making the Second Law exploitable in practical contexts. The reasons for the disappearance of disgregation, as well as of other "pre-modern" quantities, from the thermodynamics language are discussed.

A prova teórica de Boltzmann da lei de Dulong-Petit: “Uma perspectiva histórica”

“…For example, Darrigol (Darrigol, 1918), p. 130 claims that Boltzmann proved the existence of the breakdown proposed by Clausius. On the other hand, Pellegrino, Ghibaudi e Cerruti (Pellegrino, Ghibaudi and Cerruti, 2015) conclude that:…”

“…(Pellegrino, Ghibaudi and Cerruti, 2015, p. 4514) In the 1865 article, Clausius defines and proposes the term entropy for the amount of heat contained in the body as a function of temperature and disaggregation, the ratio between the sum of the variation of the internal potential energy, the work and the temperature T. That is the same Gibbs equation, with a reinterpretation of the amount of heat contained in the body in terms of internal energy, where the potential molecular energy must be incorporated. Pellegrino, Ghibaudi and Cerruti (2015), quote an observation by Leff (1996), in which he suggests that Clausius removed from the second edition of his book on the mechanical theory of heat the concept of disaggregation because he thought his result would be incorrect in relation to the application for specific heat:…”

Experimental Determination of Entropy and Exergy in Low Cycle Fatigue

“…However, the second principle allows to distinguish the different energies in particular the non equivalence heat-work. To do so, it is possible to create a thermodynamical potential taking into account the environmental effects and allowing the traduction of any energy into an equivalent quantity, a mechanical equivalent potential called exergy (see [29,30,31] for details on the history of this quantity), defined as the maximum useful work recoverable from a system in contact with the environment or as a distance from equilibrium.…”