Prigogine's theorem of minimum entropy production (Pentcho Valev)
RUMYM at BGEARN.ACAD.BG
RUMYM at BGEARN.ACAD.BG
Thu Nov 6 04:00:29 EST 1997
Bryant Fujimoto wrote:
The problem is that the flux (or flow) is defined to be the <
rate of change of a thermodynamic variable, in this case the <
concentration. Therefore dC(S2)/dt is the definition of J and /4/ <
is correct for steady state. Somebody decided that a good name for <
expressions like dC(S2)/dt would be flux or flow. So whenever the <
flux or flow is called for in this theory, that is what you must <
use. If you insert anything else, as you want to do, you will <
of course get nonsense. <
Bryant, I do not know what to say in this case. The problem is not
scientific - it is mythological, like many others in thermodynamics.
You know quite well (any student knows) that
T(dSi/dt) = AJ /1/
is derived on the strict assumption that J is the reaction rate, v.
Now if some supreme mind, in order to obtain some valuable result, has
temporarily replaced v with dC/dt, we can only wonder why this
substitution has left /1/ correct. Nobody can know that.
Still there is a straightforward analogy. Just imagine that, in order
to obtain some valuable result, I replace J in Fick's first law
J = -D(dC/dx) /2/
with dC/dt. You would explain in anger that dC/dt is given by Fick's
second law, would advise me to do my reading first etc. etc. I really
do not know what to say.
Best regards,
Pentcho
More information about the Bioforum
mailing list