Exchange, energy equilibrium

Generally, in a system that is energetically and materially isolated from the environment without a change in volume (a closed system), the entropy of the system tends to take on a maximum value, so that any macroscopic structures, except for the arrangement of atoms, cannot survive. On the other hand, in a system exchanging energy and mass with the environment (an open system), it is possible to decrease the entropy more than in a closed system. That is, a macroscopic structure can be maintained. Usually such a system is far from thermodynamic equilibrium, so that it also has nonlinearity. 

A body in dynamic equilibrium with another exchanges energy with it, yet without any net change. 

But absolute zero is unattainable, so all particles move. Furthermore, the particles never retain an invariant speed because inelastic collisions cause some particles to decelerate and others to accelerate. As a result, everything emits some electromagnetic waves, even if merely in the context of a dynamic thermal equilibrium with the object exchanging energy with its surroundings. 

ISOTORE EXCHANGE AT EQUILIBRIUM MASSIEU FUNCTION HELMHOLTZ ENERGY PLANCK FUNCTION MASS SPECTROMETRY Matrix of biominerals,... 

Closed Systems Closed systems exchange energy with their environment through their boundaries, but they do not exchange matter. The simplest example is the nonadiabatic batch reactor. These systems also tend towards a thermodynamic equilibrium with time, again characterized by maximal entropy, or the highest possible degree of disorder. 

Outside high vacuum systems we will have an ensemble of molecules that will exchange energy. Typically, thermal equilibrium will be maintained during chemical reaction. There are, though, important exceptions such as chemical reactions in flames and in explosions, as well as reactions that take place at very low pressures. 

However, natural systems consist of flows caused by unbalanced driving forces, and hence the description of such systems requires a larger number of properties in space and time. Such systems are away from the equilibrium state, and are called nonequilibrium systems, they can exchange energy and matter with the environment, and have finite driving forces (Figure 2.1). The formalism of nonequilibrium thermodynamics can describe such systems in a qualitative and quantitative manner by replacing the inequalities of classical thermodynamics with equalities. 

There are two types of macroscopic structures equilibrium and dissipative ones. A perfect crystal, for example, represents an equilibrium structure, which is stable and does not exchange matter and energy with the environment. On the other hand, dissipative structures maintain their state by exchanging energy and matter constantly with environment. This continuous interaction enables the system to establish an ordered structure with lower entropy than that of equilibrium structure. For some time, it is believed that thermodynamics precludes the appearance of dissipative structures, such as spontaneous rhythms. However, thermodynamics can describe the possible state of a structure through the study of instabilities in nonequilibrium stationary states. 

Fiocco G., Grams G. and Mugnai A., Energy exchange and equilibrium temperature of aerosols in the Earth s atmosphere. In Radiation in the Atmosphere (H.-J. Bolle Ed.), Science Press, Princeton, 1977. 

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