The University of Chicago News Office
May 5, 1995 Press Contact: Steve Koppes
(773) 702-8366
s-koppes@uchicago.edu
 

"Sound in Sand” and Other Mysteries of Granular Materials Examined in University/Industry Workshop

The University of Chicago will hold a unique university/industry workshop in materials science Thursday through Saturday, May 11 to 13. “Dynamical Processes in Granular Materials: Understanding and Control” will bring industry experts from the pharmaceutical industry, the energy industry and other industries together with scientific researchers from Chicago and other universities.

Heinrich Jaeger, Assistant Professor in Physics and one of the conference organizers, said, “The purpose of the workshop is twofold: for those of us in academia to find out what problems industry faces in working with granular materials, and for industry to find out about some of the new approaches that have been developed at the universities.”

There has been an overwhelmingly enthusiastic response to the workshop both from academia and from industry, and representatives from companies as diverse as Exxon, Bristol-Myers Squibb and Xerox will be in attendance.

Many industries depend on the processing of granular materials. Bulk commodities from flour to grain and ore are transported, stored and processed; the construction of highways and dams depends on the manipulation of large amounts of gravel and soil; the packaging of items ranging from sand in a casting form to cereal flakes in a box requires the control of granular settling as well as the control of size or shape separation; and the same is true for the handling of pharmaceutical pills, which typically are processed from fine grains or powders.

Despite the importance and ubiquity of granular materials, much of what people know about handling granular materials comes from experience and is based on trial and error rather than on a scientific understanding of how these materials behave. The Materials Research Science and Engineering Center (MRSEC) at the University of Chicago–sponsored by the National Science Foundation–was established to explore these and other problems in materials science from a joint experimental/theoretical perspective.

At Chicago, one of the problems researchers are trying to understand is how and why granular materials undergo convection when they are shaken in a cylinder. Grains at the bottom of the cylinder rise up through the middle and then down in a narrow path along the sides of the cylinder. Larger grains get trapped at the top and cannot flow back down the sides–this is the reason Brazil nuts always end up at the top of a can of mixed nuts, for example. Applying the medical technology of magnetic resonance imaging recently gave Chicago researchers an unprecedented look at what is actually happening inside the cylinder.

“This research allows us to ask questions that have immediate relevance to industry,” said Jaeger, “as well as to examine problems that are very fundamental in condensed-matter physics.”

He explained that Chicago is in a unique position to examine these sorts of questions. “Here at the University we have a long-standing history of interdisciplinary scientific research, particularly in the James Franck Institute (JFI), which is the home of MRSEC. We have a long track record as well as a very open mind-set.”

The JFI was established fifty years ago as the Institute for the Study of Metals, and its emphasis is on the chemistry and physics of solids, liquids and gases. Organized along the lines of common research interests, rather than departmental affiliations, the JFI brings together researchers from physics, chemistry, geophysics and biology.

“The smaller size of MRSEC allows us to be more flexible in the types of problems that we choose to approach, and this allows us to catch the current forefront of research,” said Jaeger. “The research that we are doing in granular materials from the experimental side is unique. And we are backed up by people who have a long-standing interest in the theoretical side, in nonlinear dynamics and chaotic systems. The combined efforts from these two sides make the University of Chicago a unique place for the study of granular materials.”

Other members of MRSEC who are working on problems in granular materials include Sidney Nagel, Professor in Physics; Leo Kadanoff, the John D. MacArthur Distinguished Service Professor in Physics; Thomas A. Witten, Professor in Physics; Peter Constantin, Professor in Mathematics; Yunson Du and Jonathan Miller, Research Associates in the James Franck Institute; Sergei Esipov, Visiting Scholar in the JFI; graduate students Elizabeth Grossman and James Knight; and several other graduate and undergraduate students. Susan Coppersmith, currently of AT&T Bell Laboratories, will be joining the faculty of the University in the fall.

Sessions slated for the workshop include talks titled “Sound in Sand," “Dynamics of Shaken Granular Materials,” “Convection and Size Separation in Granular Media” and “The Rotating Bucket of Sand,” among many others, as well as a panel discussion with representatives from both industry and academia.

 

http://www-news.uchicago.edu/releases/95/950505.granular.dynamics.shtml
Last modified at 03:50 PM CST on Wednesday, June 14, 2000.

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