Re: concepts
DON MIKULECKY (MIKULECKY%VCUVAX.BITNET@letterbox.rl.ac.uk)
Wed, 27 Sep 1995 20:04:27 -0400
> In a message dated 95-09-27 14:12:34 EDT, you write:
>
>>The way we deal with notions of open and closed in thermodynamics is
>>quite clear and unambiguous. Three types of system are possible:
>>1) isolated: enclosed by a "skin" through which matter and energy can
>>not pass: such systems must go to thermodynamic equilibrium.
>>2) closed: enclosed by a skin through which energy may pass but matter
>>may not: these systems are therefore able to maintain steady states
>>away from equilibrium as long as matter can be recycled through cycles
> within
>>3) open: both energy and matter can flow through. anything goes as
>>long as the first and second laws are obeyed.
>>
>>I suggest very strongly that we do not loose sight of these
>>definitions, since they are so widely (I'd say universally) accepted.
>>>
>
> Your #1 is a theoretical construct used for measurement approximations. It
> is more commonly called "closed".
>
> Your #2 and #3 are both open systems. Prigogine would probably call your #2
> (with the appropriate organization) a dissipative structure.
Beg to differ. The classification I gave is SRAIGHT from Prigogine and
Defay's "Chemical Thermodynamics" Sorry, but this is documentented in
LOTS of thermo texts besides theirs. Been teaching this stuff,
presenting at meetings, etc. for over 30 years. never heard of your categorizat
ion!
Respectfully,
Don Mikulecky