Talk:Quasistatic equilibrium

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"A quasistatic process is not necessarily a reversible one." Give examples of such non-reversible quasistatic processes. GangofOne 04:41, 20 December 2005 (UTC)

There is a difference between a quasi-static process and equilibrium, which can be found here - http://en.wikipedia.org/wiki/Quasistatic_process It is correctly mentioned there, that there is a lot of ambiguity in literature on the understanding of the meaning of it (quasi-static and equilibrium). While there is definitely some grounds for the ambiguity to arise, both are definitely NOT the same. I think the words "..., or equilibrium, ..." should be deleted from "In a quasistatic process, or equilibrium process, a sufficiently slow transition ..." , because they point exactly at the mistaken understanding of the concept.

Regards. —Preceding unsigned comment added by 128.205.49.63 (talk) 03:09, 1 October 2008 (UTC)

Need for a Quasi-static Equilibrium
It's unfortunate that quasi-static processes were defined so they include non-equilibrium processes and don't even exist. Yes, we all know to avoid them.

However, chemistry texts that offer such warnings give definitions of equilibrium and equilibrium paths in terms of reversibility, so geologists are often convinced equilibrium doesn't exist between minerals in rocks. A quasi-static equilibrium path does not require reversibility, and scatter-graphs show that most metamorphic and igneous rocks have taken such paths.

We can measure the rate of change of a system's environment; and by using isotopes, we can measure the rate of change of the system's reactions. When the latter are faster than the environmental change, the system will be in equilibrium at every moment. In geology, when hydrous reactions among minerals are certainly faster than changes in the environment, rocks travel equilibrium paths. The equilibrium assemblage allows one to calculate the system's environment.

This is not quite the same as 'local equilibrium', which concerns points in space, not time. There needs to be a good term for 'quasi-static equilibrium'. (Equilibrium paths can be reversible by violating the 2d Law, but are not and do not in rocks. This term will not do.)

In my own research, I've changed 'conjugate' to 'dual' and corrected other misused terms. Though the Wikipedia may not be the place to re-define a term, 'quasi-static equilibrium' is perhaps the best choice for this badly needed concept.

Geologist (talk) 13:12, 7 January 2012 (UTC)