On 24.01.2012 22:56 meekerdb said the following:

In thinking about how to answer this I came across an excellent paper by Roman Frigg and Charlotte Werndl http://www.romanfrigg.org/writings/EntropyGuide.pdf which explicates the relation more comprehensively than I could and which also gives some historical background and extensions: specifically look at section 4.## Advertising

Brent

Brent,

`I have started reading the pdf. A few comments to section 2 Entropy in`

`thermodynamics.`

The authors seem to be sloppy.

`1) p. 2 (116). "If we consider a cyclical process—a process in which the`

`beginning and the end state are the same — a reversible process leaves`

`the system and its surroundings unchanged."`

`This is wrong, as one runs the Carnot cycle reversibly, then the heat`

`will be converted to work (or vice versa) and there will be changes in`

`the surroundings. They probably mean that if one runs the Carnot cycle`

`reversibly twice, first in one direction and then in the opposite, then`

`the surrounding will be unchanged.`

`2) p. 2(116). "We can then assign an absolute entropy value to every`

`state of the system by choosing one particular state A (we can choose`

`any state we please!) as the reference point."`

`They misuse the conventional terminology. The absolute entropy is`

`defined by the Third Law and they just want employ S instead of Del S.`

`It is pretty dangerous, as when one changes the working body in the`

`Carnot cycle, then such a notation will lead to a catastrophe.`

`3) p.3(117). "If we now restrict attention to adiathermal processes`

`(i.e. ones in which temperature is constant),"`

`According to Eq 4 that they discuss they mean an adiabatic process where`

`temperature is not constant.`

However, at the end of this small section they write

`p. 3(117). "S_TD has no intuitive interpretation as a measure of`

`disorder, disorganization, or randomness (as is often claimed). In fact`

`such considerations have no place in TD."`

I completely agree with that, so I am going to read further. Evgenii -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.