Thursday, July 13, 2006
Nutty ideas spark
Sand stirs new study
By Matt Kane SPECIAL TO THE TELEGRAM & GAZETTE
Arshad A. Kudrolli,
associate physics professor at
holds granular samples.
under the direction of Mr. Kudrolli. (T&G Staff/TOM RETTIG)
nuts are found at the top of a can
of mixed nuts, what causes a snow
avalanche and what holds a
sandcastle together.
“You can get a Ph.D. in physics playing in a sandbox,” said
graduate
student Kevin T. Safford, standing
by a giant tub of sand in the
laboratory.
A $327,000 grant to
Foundation will fund research on granular physics, the study
of how
masses of particles such as sand
and grains behave. Arshad A.
Kudrolli, an associate physics
professor at
undergraduate and graduate
researchers in a project: “Statistical and
Dynamical Properties of Spherical and
Non-Spherical Granular Materials.”
Mr. Kudrolli described his
research as “trying to find out a few
variables which capture the
properties of granular materials.” The
behavior of these materials must be
studied before developing
mathematical formulas and physical
laws to describe them, he said.
In a back room of the physics lab, a chain of metal beads
vibrated
slightly on an electromagnetic
shaker, a vibrating plate, while a
high-speed camera recorded its
movement. Mr. Safford, one of the
researchers working with Mr. Kudrolli, watched a movie of the chain’s
movement on a nearby computer
screen.
Mr. Safford analyzes numerical data generated from these
movies to
determine whether simple chains of
metal beads can be used to model
polymers, long complex chains of
repeated molecules. The movement of
a beaded chain might eventually be
used to model the splitting of DNA
in a cell or the behavior of E.
coli bacteria, Mr. Safford said.
“It is applicable everywhere. I now have an opportunity to
learn
about all kinds of things that I’ve
never studied before,” Mr.
Safford said.
The grant will allow the lab to purchase a more advanced
high-speed
camera and more computers. This new
technology will accelerate the
experimentation process, allowing
the researchers to do more, Mr.
Safford said.
Researchers in the lab have studied why Brazil nuts usually
end up
near the top of a can of mixed
nuts, a counterintuitive phenomenon
since
Brazil nut effect, Mr. Safford explained, larger grains will
often
remain at the top of a granular mix
because smaller grains can fall
through the spaces to the bottom.
Ashish V. Orpe,
a post-doctorate researcher in the lab, said masses
of grains behave like solids when
they are in a heap, like liquids
when they take the shape of a
container, and like gases when they are
shaken. He said the kinetic theory
of gases can be applied to
agitated grains.
“It shows all three stages of matter within a single
system,” Mr.
Orpe said.
Mr. Safford pointed to a newspaper article hanging on the
lab wall
about the collapse of an earth wall
on a parkway in
researchers hope to eventually
prevent these types of catastrophes by
modeling granular properties.
Mr. Kudrolli left for
the
fluid flow workshop organized by
the Gordon Research Conference in
His work has been featured in New Scientist Magazine, Nature
Physics,
National Geographic and Popular Science
magazine and on CNN. He has
been at
“Professor Kudrolli has been
studying the behavior of granular media
with support of the NSF since he
arrived at
of the young leaders in this
field,” Christopher P. Landee, chairman
of