Temperature In Thermodynamics Research Articles

Theory of powders

Starting from the observations that powders have a large number of particles, and reproducible properties, we show how statistical mechanics applies to powders. The volume of the powder plays the role of the energy in conventional statistical mechanics with the hypothesis that all states of a specified volume are equally probable. We introduce a variable X-the compactivity - which is analogous to the temperature in thermodynamics. Some simple models are considered which demonstrate how the problems involved can be tackled using the concept of compactivity. There is an increasing interest in applying the methods of statistical mechanics and of transport theory to systems which are neither atomistic, nor in equilibrium, but which still fulfil a remaining tenet of statistical physics which is that systems can be completely defined by a very small number of parameters and can be constructed in a reproducible way. Powders fall into this category. If a powder consists for example of uniform cubes of salt, and is poured into a container, falling at low density uniformly from a great height, one expects a salt powder of a certain density. Repeating the preparation reproduces the same density. A treatment such as shaking the powder by a definite routine produces a new density and the identical routine applied to another sample of the initial powder will result in the same final density. Clearly a Maxwell demon could arrange the little cubes of NaCl to make a material of different properties to that of our experiment, but if such demonics are ignored, and we restrict ourselves to extensive operations such as stirring, shaking, compressing - all actions which do not act on grains individually - then well defined states of the powder result. In this paper we will set up a framework for describing the state of the powder, basing our development on anologies with statistical mechanics. Some attempts have been made to apply information theory ideas directly to powders

Social entropy, enthalpy, exergy and disergy in examples

For the thermodynamic terms entropy, enthalpy and exergy, parallel terms for the psychosocial area of communication are illustrated. The thermodynamic notion energy is paralleled by dynamic information, the molecule by a goal-oriented social individual, exergy by the maximum goal attainment of the individuals who constitute a communication system, enthalpy by the will of action and the associated activity and entropy by the density of communication, the amount of information exchanged and the classification of communication (as devotional, aggressive or destructive). The absolute temperature in thermodynamics is paralleled by the speed with which information is exchanged. The term disergy ( distracting en ergy) is added and illustrated in cases where the communication system is open to outside environment.

Interrelation between time-rates of temperature and deformation in continuum thermodynamics

It is shown that in a body, the time-rates of the deformation function and temperature distribution function cannot, in general, be assigned independently of each other. The implications of this result on the modern approach to continuum thermodynamics are briefly discussed.

On the existence of a single temperature in continuum thermodynamics

A global hypothesis involving the heat flux and the entropy flux is shown to be equivalent to the existence of temperature.

Temperature of a Moving Body

LANDSBERG1,2 has raised the question of the correct definition of temperature in relativistic thermodynamics. He advances2 a general case against the orthodox transformation of temperature by considering the case of two systems, possessing equal proper temperatures, T0, and in relative motion. Then observers moving with the two systems will each judge the temperature of the other system to be lower than that of the system with which he is moving. If the usual relation exists between temperature difference and heat flow, both proper temperatures should fall, a conclusion Landsberg finds unacceptable. The argument is not, however, completely convincing, and Williams3 has pointed out that the direction of energy flow between two systems is, in general, dependent on the frame of reference in which the flow is observed.