Re: dS=0

[Jim Green <JMGreen@SISNA.COM>]

Bob, again I have not expressed myself well:  I am after an infinitesimal
process -- such as compressing the usual piston by dV -- not a cycle or
even any kind of integral --  In the case of this usual piston  dV---->dS=0
identically and if not uniquely, then uncommonly.   I surmise that all
classical thermo is based on this accident -- only because Carnot was
interested in steam engines and hence simplified the problem to the
standard piston and cylinder.

Jim



> Eg: an infinite variety of closed cycle processes are possible (using an
> infinite variety of various combinations of Q things and W things), all
> resulting in zero entropy change of the system.
>
> Bob
>
>
> Bob Sciamanda (W3NLV)
> Physics, Edinboro Univ of PA (em)
> trebor@velocity.net
> http://www.velocity.net/~trebor
>
> ----- Original Message -----
> From: Jim Green <JMGreen@SISNA.COM>
> To: <PHYS-L@lists.nau.edu>
> Sent: Friday, January 07, 2000 1:13 PM
> Subject: Re: dS=0
>
>
> >  . . .
> > The question on the page is "Why, if both Q-things and W-things are both
> > mechanical work, what then is the difference between W and Q if any?"
> The
> > answer is that Q-things change the entropy and W-things do not . . .

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen