This chapter discusses Edward's Statistical Mechanics approach to granular media in the framework of schematic hard spheres lattice models. As this approach appears to hold to a very good approximation, by analytical calculations of Edward's partition function at a mean field level, the chapter describes the derivation of the system phase diagram and shows that "jamming" corresponds to a phase transition from a "fluid" to a "glassy" phase, observed when crystallization is avoided. The nature of such a "glassy" phase turns out to be the same found in mean field models for glass formers. The chapter also focuses on mixing/segregation phenomena of binary mixtures--the presence of fluid-crystal phase transitions drives segregation as a form of phase separation and, within a given phase, gravity can also induce a kind of "vertical" segregation, usually not associated to phase transitions.
Statistical Mechanics of jamming and segregation in granular media
M Nicodemi;A Coniglio;A de Candia;A Fierro;
2004-01-01
Abstract
This chapter discusses Edward's Statistical Mechanics approach to granular media in the framework of schematic hard spheres lattice models. As this approach appears to hold to a very good approximation, by analytical calculations of Edward's partition function at a mean field level, the chapter describes the derivation of the system phase diagram and shows that "jamming" corresponds to a phase transition from a "fluid" to a "glassy" phase, observed when crystallization is avoided. The nature of such a "glassy" phase turns out to be the same found in mean field models for glass formers. The chapter also focuses on mixing/segregation phenomena of binary mixtures--the presence of fluid-crystal phase transitions drives segregation as a form of phase separation and, within a given phase, gravity can also induce a kind of "vertical" segregation, usually not associated to phase transitions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.