Fig. 1.5 An example of quasi-static process: it can be an expansion process if ~ F gas (= pA piston ) is
slightly greater than ~ F ext with piston moving right, or a compression process in the opposite case.
Note that the figure implies the existence of a mechanical arrangement for maintaining the required
~ F ext ––including the existence of a work reservoir (see discussion in Sect. 1.9)
Stoppage-pieces to keep
the piston in place
Fig. 1.6 Another example of a quasi-static process, resulting from the removal of closely spaced
constraints: As it will be discussed in Chap. 6, with the proper arrangement, such kind of
quasi-static process can be made to follow the same path as the above one in Fig. 1.5. In other
words, not only work is path dependent but also two work processes along exactly the same path
(as shown in Fig. 1.5 and here) can be different from each other
18
1 Introduction: Temperature and Some Comment on Work
slightly greater than ~ F ext with piston moving right, or a compression process in the opposite case.
Note that the figure implies the existence of a mechanical arrangement for maintaining the required
~ F ext ––including the existence of a work reservoir (see discussion in Sect. 1.9)
Stoppage-pieces to keep
the piston in place
Fig. 1.6 Another example of a quasi-static process, resulting from the removal of closely spaced
constraints: As it will be discussed in Chap. 6, with the proper arrangement, such kind of
quasi-static process can be made to follow the same path as the above one in Fig. 1.5. In other
words, not only work is path dependent but also two work processes along exactly the same path
(as shown in Fig. 1.5 and here) can be different from each other
18
1 Introduction: Temperature and Some Comment on Work