"One of the remarkable things that people see in glassy systems is that they often seem to have a memory," Zhang said. "There's a difference between how the material behaves if you simply cool it versus you cool it, reheat it and cool it again. It seems to remember what you've done to it, and we're not quite sure how."
Along with jamming and memory, singularities also can control the dynamics, shape and overall evolution of catastrophic deformation processes. Where singularities occur, scientists encounter great difficulty in using equations to describe the behavior of fluid motion.
"The governing equations for these are inexcusably horrible," Nagel said. And yet they govern the behavior of fluids on Earth, gases in outer space and perhaps even the internal dynamics of the atom. "It's these kinds of equations that govern the texture and form of our lives," he said.
The researchers have applied $1 million of the total funding to developing instruments that will advance current capabilities in ultrafast imaging. They will develop a high-speed imaging apparatus using X-rays produced at the Advanced Photon Source at Argonne National Laboratory to study granular materials.
The team also will combine new camera technology with a confocal microscope, an instrument for producing enhanced images in a narrow field of view. The setup will allow the Chicago team to take images at near-video rates of approximately 30 frames each second, which is critical for studying the properties and dynamics of proteins and cells. The previous state-of-the-art of confocal microscopy limited the image rate to approximately one frame every second.
"Different timescales tell you different things about the behaviors of materials," Gardel said. Silly Putty, for example, will break like a solid when slammed against a tabletop. But when pulled apart slowly, it deforms like a liquid. Scientists ob
|Contact: Steve Koppes|
University of Chicago