Contact Temperature as an Internal Variable of Discrete Systems in Non-Equilibrium

TL;DR

This paper explores the role of contact temperature as an internal variable in non-equilibrium thermodynamics of discrete systems, discussing its evolution and relation to internal variables and degrees of freedom.

Contribution

It introduces the concept of contact temperature as an internal variable and presents its evolution equation within the framework of non-equilibrium thermodynamics.

Findings

Contact temperature is identified as an internal variable.

Evolution equations for contact temperature are derived.

The distinction between internal variables and degrees of freedom is clarified.

Abstract

State space and entropy rate of a discrete non-equilibrium system are shortly considered including internal variables and the contact temperature. The concept of internal variables in the context of non-equilibrium thermodynamics of a closed discrete system is discussed. The difference between internal variables and degrees of freedom are repeated, and different types of their evolution equations are mentioned in connection with G\'{e}rard A. Maugin's numerous papers on applications of internal variables. The non-equilibrium contact temperature is recognized as an internal variable and its evolution equation is presented.