Carnots Engine and Temperature

Consider a fluid undergoing a cyclic transformation shown in Fig. 1.10. The upper graph shows the cycle in the F-F-plane, whereas the lower is a sketch illustrating the working principle of a corresponding device. Here the amount of heat q2 is transferred from a heat reservoir at temperature O2 (62 1) to the device. During the transfer (path from a to in the F-F-diagram) the temperature in the device is 6 2. This part of the process is an isothermal expansion. Then the device crosses via adiabatic expansion to a second isotherm at temperature 9, the temperature of a 

Rudolf Julius Emanuel Clausius, German physicist, K6slin (now Koszalin) 2.1.1822, fBonn 24.8.1888 one of the developers of the mechanical theory of heat his achievements encompass the formulation of the second law and the introduction of the entropy concept. 

Pathria (1972) Hence, for the constancy of S (Entropy) and N (number of particles), which defines an adiabatic process,.  

Fermi (1956) A transformation of a thermodynamic system is said to be adiabatic if it is reversible and if the system is thermally insulated so that no heat can be exchanged between it and its environment during the transformation  

Pauli (1973) Adiabatic During the change of state, no addition or removal of heat takes 

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