PHYSICAL MATHEMATICS SEMINAR



TOPIC:	GASES, LIQUIDS AND CRYSTALS IN GRANULAR SEGREGATION



SPEAKER:	PEDRO MIGUEL REIS
		Manchester Centre for Nonlinear Dynamics
		University of Manchester, United Kingdom


ABSTRACT:

We report the results of an investigation of segregation in a binary mixture of 
dry particles subjected to horizontal oscillatory excitation. In our experiments, 
a thin layer of particles is driven by the stick-slip frictional interaction with the 
surface of a horizontal tray. As the packing fraction of the mixture is increased 
the evolution of distinct phases is observed, which we identify as binary gas, 
segregation liquid and segregation crystal. Both microscopic and macroscopic 
measures are used to study the properties of these three phases and study the
associated transitions. We develop a reductionist model for our system and explore 
it via Event Driven simulations. This model is found to reproduce much of the 
experimentally observed behaviour, most importantly the transition between the 
mixed to segregated state. Finally, we draw some speculative analogies between 
segregation in our granular system and self-assembly in binary colloidal mixtures.	


(Dr. Pedro Miguel Reis is currently visiting the Levich Institute, CCNY, New York.)


TUESDAY, MAY 18, 2004
2:30 pm
Building 2, Room 338

Refreshments will be served at 3:30 PM in Room 2-349

Massachusetts Institute of Technology,  Department of Mathematics, Cambridge, MA  02139