In the framework of schematic hard spheres lattice models we discuss Edwards' Statistical Mechanics approach to granular media. As this approach appears to hold here to a very good approximation, by analytical calculations of Edwards' partition function at a mean field level we derive the system phase diagram and show 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. In the same context, we also briefly discuss 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 / Nicodemi, Mario; A., Coniglio; DE CANDIA, Antonio; A., Fierro; M. P., Ciamarra; M., Tarzia. - STAMPA. - (2004), pp. 47-61. (Intervento presentato al convegno International Workshop on Unifying Concepts in Granular Media and Glasses tenutosi a Capri, Italy nel 25-28 June 2003) [10.1016/B978-044451607-7/50005-4].
Statistical Mechanics of jamming and segregation in granular media
NICODEMI, MARIO;DE CANDIA, ANTONIO;
2004
Abstract
In the framework of schematic hard spheres lattice models we discuss Edwards' Statistical Mechanics approach to granular media. As this approach appears to hold here to a very good approximation, by analytical calculations of Edwards' partition function at a mean field level we derive the system phase diagram and show 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. In the same context, we also briefly discuss 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.
