STRUCTURE OF VARIATIONAL-PRINCIPLES IN NONEQUILIBRIUM THERMODYNAMICS

There are a lot of different methods to construct variational principl es in physics. In this paper we investigate and classify some of the k nown methods, focusing our treatment mainly on the variational princip les in nonequilibrium thermodynamics. This area of physics is remarkab ly rich in different variational methods, because here we cannot obtai n a classical, Hamiltonian variational principle for the transport equ ations, as far as if we consider them in their original form and with their original variables.