THE LEVICH INSTITUTE ANNOUNCES THE FOLLOWING SEMINAR
Tuesday, 10/24/2000
4:00 PM
Steinman Hall, Room #1M-22
Dr. Thomas Mason
Corporate Strategic Research
Exxon Mobil Research and Engineering Company
"How Sandcastles Fall: From Wet Sandpiles to Dimer Sandpiles"
ABSTRACT
We explore how the maximum static stable angle, or critical angle, of a
sandpile of rough spherical grains increases as a very small quantity of
liquid is added and distributed evenly within the sandpile. This increase
can be quantitatively explained by the development of halo-like menisci
between grains at their contact points; these menisci provide cohesive
forces that are sensitive to the air-liquid interfacial tension. Motivated
by the idea that disconnected clusters of grains may form at the very
lowest liquid content, we have constructed dry sandpiles of mixtures of
monomer and dimer grains and measured the critical angle as a function of
relative dimer volume fraction. Direct imaging of the grains on the
sandpile's surface confirms a theoretical model that sandpiles comprised of
dimer grains have more corrugated surfaces and a higher critical angle than
sandpiles comprised of spherical monomer grains.
BRIEF ACADEMIC/EMPLOYMENT HISTORY:
- Ph.D. Princeton Physics Dept. (1995)
- Postdoc- CNRS Bordeaux, France (1995-96)
- Postdoc- Johns Hopkins U. (1996-97)
- Senior Physicist - Exxon Mobil Research and Engineering Company (1997-present)
RECENT RESEARCH INTERESTS:
Complex fluids and granular materials: emulsion
rheology, sandpile failure, light scattering methods, neutron scattering,
petroleum physics.
Return to Fall, 2000 Seminar Schedule