On the thermodynamics of far-from-equilibrium dissipative systems

We consider the question of the concepts of entropy and temperature in arbi trary nonequilibrium conditions in the framework of the so-called Informati onal Statistical Thermodynamics. This is the approach to Thermodynamics bas ed on the statistical-mechanical foundations provided by a Gibbs ensemble-l ike algorithm in nonequilibrium situations. The resulting nonequilibrium te mperature-like variable dubbed as quasitemperature - is shown to be a quant ity measurable with appropriate "thermometric devices". A comparison of qua sitemperatures that arise in different approximated nonequilibrium statisti cal-thermodynamic descriptions of the dissipative system is done. The valid ity of these different approximations is evaluated, and (in the framework o f the theory) generalized Gibbs, Clausius, and Boltzmann's relations, as we ll as properties of the corresponding entropy-like function (or information al entropy in Jaynes-Shannon sense), that the theory introduces, are presen ted. Conceptual and physical aspects of the question an also discussed, and a partial comparison of these concepts with those arising in other approac hes to irreversible thermodynamics is briefly attempted.