Reservoir concept temperature

Considering the concepts of reversible processes, a reversible cycle can be carried out for given thermal reservoirs at temperatures and Tl. The Carnot heat engine cycle on a p-V diagram and a T-S diagram, as shown in Fig. 1.4 is composed of the following four reversible processes ... 

Heat q and temperature T are related but distinct concepts. Temperature T can be identified as degree of hotness (Section 2.3), whereas heat q is a quantity of thermal energy. The same quantity of heat might be stored under different conditions, for example, as high-temperature heat or low-temperature heat in heat reservoirs of different temperature. Further aspects of how the temperature of a heat quantity affects its usefulness (e.g., for conversion to useful work) will be discussed in Chapter 4. 

The next concept which proves useful in developing new chemical oscillators is that of bistability along with the related notion of hysteresis. An open chemical system, such as a reaction in a CSTR, may have two (or more) different stable steady states under the same external constraints, i.e., values of the input flow rate, reservoir concentrations, temperature and pressure. In such a situation, transitions from one state to another show hysteresis, occurring at different points depending upon the direction in which the constraints are changed. An example of this behavior is shown in Figure 2. As the iodide... 

Carnot efficiency is one of the cornerstones of thermodynamics. This concept was derived by Carnot from the impossibility of a perpetuum mobile of the second kind [ 1]. It was used by Clausius to define the most basic state function of thermodynamics, namely the entropy [2]. The Carnot cycle deals with the extraction, during one full cycle, of an amount of work W from an amount of heat Q, flowing from a hot reservoir (temperature Ti) into a cold reservoir (temperature T2 < T ). The efficiency r] for doing so obeys the following inequality ... 

The second major development has been the evolution of the paleopasteurization concept (Wilhems et al., 2001). Paleopasteurization explains why it is possible to observe reservoirs of nondegraded cmde oils at relatively shallow depths in the subsurface where one might expect the oils to be degraded. The explanation makes use of the fact that, in general, biodegradation of crude oils has not been reported in reservoirs that have experienced temperatures above 80 °C. For paleopasteurization to occur, a reservoir will have to have been exposed to temperatures above 80 °C at some time during its history. Above that temperature, the reservoir is effectively sterilized... 

A consequence of the impossibility of converting heat isothermally into work in a continuous manner is the impracticability of what is called perpetual motion of the second kind/ that is, the utilization of the vast stores of energy in the ocean and in the earth. There is nothing contrary to the first law of thermodynamics in this concept, but the fact that it has not been found feasible provides support for the second law. The ocean, for example, may be regarded as a heat reservoir of constant temperature, and the law states that it is not possible to convert the heat continuously into work without producing changes elsewhere. 

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