Volume 38, Issue 4

Abstract. Functions, not dynamical equations, are the definitive mathematical objects in equilibrium thermodynamics. However, more than one function is often described as “the” equation of state for any one physical system. Usually these so named equations only capture incomplete physical content in the relationships between thermodynamic variables, while other equations, no less worthy of the name equation of state, go inconsistently by other names. While this approach to terminology can be bewildering to newcomers, it also obscures crucial properties of thermodynamic systems generally. We introduce specific principal equations of state and their complements for ideal gases, photons, and neutrinos that have the complete thermodynamic content from which all other forms can be easily deduced. In addition to effortlessly clarifying many smaller classical issues, they also make properties like the second law of thermodynamics and local thermodynamic equilibrium completely visual.

Abstract. Relationships between lost available work and entropy generation cannot be obtained in the general case, i.e., for systems in contact with arbitrary heat and/or radiation reservoirs. Reservoirs in local (full or partial) thermodynamic equilibrium are needed. The Gouy–Stodola theorem is a particular case of a more general result obtained for systems in contact with heat reservoirs in local thermal equilibrium. Radiation reservoirs cannot be assimilated to heat reservoirs. A general model of a radiation reservoir is shown. Particular cases are reservoirs containing black-body radiation, deformed black-body radiation, and nuclear radiation. Despite the case of heat reservoirs, knowledge of their temperature is not sufficient for a complete characterization of radiation reservoirs. There is a need to know other intensive thermodynamic parameters, such as the chemical potential of radiation as well as some macroscopic parameters (such as the geometric characteristics of the radiation reservoir) and microscopic parameters (such as radiation spectra or band-gaps). Some types of radiation reservoirs may behave like heat reservoirs, but only in the classical approximation .

Abstract. We develop a mesoscopic model of thermoelectric coupling in nanosystems, allowing for different phonon and electron temperatures, and mutual energy exchange. Its compatibility with the second law of thermodynamics is proved. By comparisons with other theoretical proposals, the different coefficients involved in the model are identified. We consider two illustrations: (a) for systems where the electron mean-free path is considerably shorter than the phonon mean-free path, the non-equilibrium phonon temperature may be different with respect to the local-equilibrium temperature of electrons; (b) for systems with large electron mean-free path, one may have the so-called “hot electrons,” namely, electrons having a higher temperature than that of the phonons.

Abstract. The authors have taken measurements on hydrodynamic and electro- osmotic permeation of water and aqueous salt solutions of , , and in the concentration range  M to  M, across pyrex-sintered glass membrane (G-3). The data obtained were used to ascertain the form of transport equation using the theory of non-equilibrium thermodynamics. Phenomenological coefficients, average pore radius, number of pores, and membrane constant have been evaluated. Zeta potential values have been evaluated to characterize the electrical nature of the membrane–permeant interface.

Abstract. The numerical solution of the Boltzmann equation for the thin film applications requires extensive computational power. An analytical solution to the phonon transport equation is fruitful in order to reduce the computational effort and cost. In the present study, an analytical solution for the phonon radiative transport equation in thin film is carried out. The analytical treatment of the problem reduces the two identical radiative transport equations to Fredholm integral equation of the second kind. The resulting phonon intensity data are presented in terms of the dimensionless temperature across the gray thin films of silicon and diamond. The findings are compared with their counterparts predicted from the numerical simulations. The study is extended to include the effect of the film thickness on the dimensionless temperature distribution. It is found that the analytical solution for temperature agrees well with the numerical predictions. Reducing the film thickness increases the temperature jump at the film edges, which is more pronounced for the diamond film.

Abstract. Acceleration-sensitive materials have properties which depend on the motion of the material. This motion refers to an arbitrary chosen standard frame of reference and does not depend on observers, which can be changed without changing the material properties. Consequently, one has properly to distinguish between changing the observer and changing the motion of the material. This is achieved by extending the domain of the material mapping by a second entry describing the material's motion independently of the chosen observer.