Conservative and dissipative phenomena in thermodynamical systems stability

Abstract The entropy production of thermodynamical systems with reversible (conservative) and irreversible (dissipative) phenomena is used as a Lyapunov candidate function to address stability properties. First, based on the conjugated variables of the extensive properties, the dissipative and conservative phenomena are identified, then, the dynamic behavior of entropy production is obtained. Based on the properties of the entropy function Hessian, it is found that dissipative phenomena contribute to stability and attraction of the thermodynamical equilibrium. In particular, when only dissipative phenomena are present, the entropy production is a Lyapunov function that guarantees global or local stability, depending on the nonlinearities. Complex behaviors, for instance transitory increments of the entropy production, are due to both conservative phenomena and, far from equilibrium, non linearities of dissipative phenomena.Finally, a case study consisting in a gas -piston system is presented to illustrate these ideas

Generalized Hamiltonian representation of thermo-mechanical systems based on an entropic formulation

In this work, we present an approach to construct generalized Hamiltonian representations for thermo-mechanical systems. Using entropic formulation of thermodynamic systems, the construction is applied to a class of thermo-mechanical systems. The proposed approach leads to an explicit expression of the dissipation along the trajectories of the dynamics. The considered thermo-mechanical systems are, in a thermodynamical sense, systems for which the dynamics of the extensive variables are functions of the intensive variables with respect to an entropic formulation. Using the entropy as the storage function, the dissipative structures of an analogue to a port-controlled Hamiltonian (PCH) representation are identified with irreversible phenomena, while the conservative structures are identified with reversible or isentropic phenomena. Examples are presented to illustrate the application of the proposed methodology, including a reacting system

Changing the Flow: A Blueprint for Federal Action on Water

This report outlines the steps necessary to create an effective freshwater strategy in Canada, created by the Gordon Water Group of Concerned Scientists and Citizens (now FLOW). The Gordon Water Group was founded in part by three POLIS Research Associates. The Group brings together a number of organisations, including the Water Sustainability Project and scientific expertise on sustainable water management.The Gordon Water Group gratefully acknowledges the financial support of the Walter and Duncan Gordon Foundation that has made this blueprint possible.FacultyReviewe