Thermodynamic System

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thermodynamic system

[¦thər·mō·dī′nam·ik ′sis·təm]
A part of the physical world as described by its thermodynamic properties.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Thermodynamic System


an aggregation of physical bodies that may interact with each other and may exchange energy and mass with other bodies. Thermodynamic systems are the objects of study of thermodynamics.

A thermodynamic system consists of such a large number of particles that the system’s state may be characterized by macroscopic parameters—for example, density, pressure, and the concentrations of the various substances forming the system. If a system’s parameters do not vary with time and if there are no steady fluxes in the system (such as fluxes of heat or mass), the system is said to be in equilibrium (seeEQUILIBRIUM, THERMODYNAMIC). The concept of temperature as a state parameter having the same value for all macroscopic parts of the system is introduced for systems in equilibrium.

The properties of thermodynamic systems in thermodynamic equilibrium are studied by equilibrium thermodynamics, or thermostatics; the properties of nonequilibrium systems are studied by nonequilibrium thermodynamics. Thermodynamics deals with closed, open, adiabatic, and isolated systems. Closed systems do not exchange mass with other systems. Open systems may exchange mass and energy with other systems. Adiabatic systems do not exchange heat with other systems. Isolated systems exchange neither energy nor mass with other systems.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Based on Boltzmann's observation that a thermodynamical system evolves toward the equilibrium state, which is the most probable one, Gibbs introduced in 1902 the criterion of maximum entropy.
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Thermodynamical systems in which matter creation occurs belong to the class of open thermodynamical systems, in which the usual adiabatic conservation laws are modified by explicitly including irreversible matter creation [49].