Re: Thermo/Sidebar

[Jim Green <JMGreen@SISNA.COM>]

> >But my question is whether there is _any_ example of a macroscopic
> >reversible process other than the ideal piston in a cylinder.

John suggests the following:

> 1) Springs are missing iff they have been arbitrarily ruled out.

Well, John, I don't rule them out -- in fact this may be another example --
such as I have been looking for:

Are you suggesting an "ideal" (ie reversible ie coefficient of restitution
of unity) spring (or say a rubber ball) with a platform mounted upon it --
such that sand might be poured upon the platform quasi-statically?

A calculation of deltaW seems straight forward but how would one calculate
deltaS? Can one calculate a density of states?

Hummmm, let me think on this.

The following don't seem macroscopic to me:

> 2) What about the thermodynamics of chemical equilibrium?  pH and pKa and
> all that?
>
> 3) What about the thermodynamics of charging a battery?

I must confess that I don't know much about the following:

> 4) What about the thermodynamics of a dilution refrigerator, e.g. the
> venerable Electrolux cycle, or the 3He-4He dilution refrigerator?
>
> 5) Perhaps simplest of all, what about the thermodynamics of an adiabatic
> demagnetization refrigerator?

In what sense are they macroscopic the way the classical cylinder is?  How
would I calculate deltaQ, deltaW and deltaS for a cycle?

TX for the suggestions.

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