Scientific Events

We formulate a theory of non-equilibrium statistical thermodynamics for ensembles of atoms or molecules. The theory is an application of Jayne's maximum entropy principle, which allows the statistical treatment of systems away from equilibrium. In particular, neither temperature nor atomic fractions are required to be uniform but instead are allowed to take different values from particle to particle. In addition, following the Coleman-Noll method of continuum thermodynamics we derive a dissipation inequality expressed in terms of discrete thermodynamic fluxes and forces. This discrete dissipation inequality effectively sets the structure for discrete kinetic potentials that couple the microscopic field rates to the corresponding driving forces, thus resulting in a closed set of equations governing the evolution of the system. We complement the general theory with a variational meanfield theory that provides a basis for the formulation of computationally tractable approximations. We present several validation cases, concerned with equilibrium properties of alloys, heat conduction in silicon nanowires, hydrogen desorption from palladium thin films and segregation/precipitation in alloys, that demonstrate the range and scope of the method and assess its fidelity and predictiveness. These validation cases are characterized by the need or desirability to account for atomic-level properties while simultaneously entailing time scales much longer than those accessible to direct molecular dynamics. The ability of simple meanfield models and discrete kinetic laws to reproduce equilibrium properties and long-term behavior of complex systems is remarkable. [more]

The Max-Planck-Insititut für Eisenforschung in Düsseldorf cordially invites academic and industrial researchers to the workshop on WEM formation, taking place on October 23^nd 2018. This workshop will focus on the fundamental materials scientific processes behind this phenomenon. For this we have invited a number of speakers from complementary fields that are crucial for understanding the phenomenon. Topics will range from WEM formation mechanisms in bearings and rails, over WEM generation by heat, surface machining and high pressure torsion, and the role of hydrogen and electric current, to the remarkable resistance of high nitrogen steels to WEC failure. Participants must register till September 30^th. The event is financed by the BMBF through grant 03SF0535 and is free of charge. [more]