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Thermodynamic Geometry. Peter Salamon Udine Advanced School October 2005. Finite Time Thermodynamics. 3 (at least) Big Questions Maximum power Minimum dissipation Thermodynamic waiting time Number of fluctuations 1 (at least) Big Failing No contact with experiment. Min S u. Max
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Thermodynamic Geometry Peter Salamon Udine Advanced School October 2005
Finite Time Thermodynamics • 3 (at least) Big Questions • Maximum power • Minimum dissipation • Thermodynamic waiting time • Number of fluctuations • 1 (at least) Big Failing • No contact with experiment
Min Su Max Power Given that something should happen, How much we care about wasting fuel In between lies: Economics, Biology, ??
Economics -- • marginal propensity to consume power. • Industrialist vs. Environmentalist • Should the marginal propensity to consume power be the same across a well equilibrated market? Other input to production
Biology Examples -- • Is there a lion chasing me? • What degree of flagellar stirring should I do to get the most food (O2). Degree of multicellularity as a function of Peclet number. (Ray Goldstein, U. of Ariz.)
Finite Time Thermodynamics • 3 (at least) Big Questions • Maximum power • Minimum dissipation • Thermodynamic waiting time • 1 (at least) Big Failing • No contact with experiment Endoreversible Geometry Untried One sad story in second lecture
Minimum Dissipation • Measured by lost exergy or by entropy produced. • Gouy-Stodola
Basic physical problem: • How much entropy must be produced to bring a system along a given sequence of states? • Example: Heat a cup of coffee.
… Tn T0 T1 Entropy production is a small equilibration
What does distance measure? • Velocity -- shock tube • dL2 = dissipation in a small equilibration • Fluctuation
"Thermodynamics is the only physical theory of universal content which, within the framework of the applicability of its basic concepts, I am convinced will never be overthrown." — Albert Einstein Thermodynamics is almost mathematics.