To Improve Forecasting Earthquakes, NJIT Mathematician Studies Grains
A new and better way to predict earthquakes and avalanches may soon be available to forecasters thanks to mathematical research underway at NJIT. Using mathematical modeling, researchers are investigating how forces and pressures propagate through granular materials.
“Computational Homology, Jamming and Force Chains in Dense Granular Flows,” a four-year, $378,603 National Science Foundation grant has been awarded to Louis Kondic, associate professor of mathematical sciences at NJIT. Kondic will study how the physical properties of granular materials, like sand or salt, can lead to jamming, large force fluctuations and ultimately how they can pressure a building to topple. Both earthquakes and avalanches involve similar materials and reactions.
“The mystery is to learn how forces and pressure propagate or move through grains,” said Kondic. “We know the answer for liquids, but for granular materials, we do not. As a result, it is difficult to build efficient devices for dealing with them. Silos can collapse due to non-uniform pressures on their walls. Salt, sand or coal often jams when flowing out of hoppers. But why they behave like this remains unknown.”
In 2006, Kondic was the co-author of “On Velocity Profiles and Stresses in Sheared and Vibrated Granular Systems Under Variable Gravity” which appeared in Physics of Fluids. Other articles by him investigating similar research have appeared in Applied Mathematics and Mechanics (2008), SIAM News (2007) and Physics Review E (2005). Kondic can be reached via email at Kondic@njit.edu.
The current project centers on so-called force chains, which are crucial for understanding granular systems. The attached figure shows computer simulations of heterogeneous, ramified structures (colored yellow). “Similar forces do not propagate uniformly, but instead form chain-like structures,” said Kondic. “We will propose new mathematical methods for quantifying these structures. The algorithms will account for the geometrical properties of the forces. Such a generalized model that describes the properties of these features does not exist.”
According to Kondic, the research applies to earthquakes and avalanches because when tectonic plates move, they can cause an earthquake. Where the points of these plates meet, the material will typically be in a granular form. Researchers now believe that a better understanding of the forces that exist in this granular state can lead to new methods for predicting when and where earthquakes and/or avalanches will occur.
This project will employ a highly interdisciplinary approach that integrates new geometrical techniques, modeling, and experiments. It will address fundamental questions concerning the physical properties of granular media and other jammed materials such as glasses, foams, and colloids.
Although the existence of force chains has been known for decades, a quantitative understanding of their role in physical processes has proved to be elusive because previous studies have been unable to devise an unbiased and general definition for them. Precise identification and characterization of force chains and the response of jammed materials to applied forces will likely have a transformative impact in many arenas.
The NJIT study is part of a larger NSF project involving Robert P. Behringer, professor of physics, Duke University; Konstantin Mischaikow, professor, department of mathematics, Rutgers University-New Brunswick; Corey O'Hern, associate professor, departments of mechanical engineering and physics, Yale University.
Prof's Whale Duet "Thousand Mile Song" Makes Top 10 Science Book List
Whale sounds from thump to song have long struck a chord with NJIT humanities professor, writer and musician David Rothenberg. The rhythms so captivated the intrepid clarinetist that he spent much of last year playing interspecies duets with these melodic mammals. And now, Rothenberg's new book Thousand Mile Song: Whale Music in a Sea of Sound (Basic Books, May 1, 2008) has been named one of the ten best science and technology books for 2008 by Booklist on Line, a publication of the American Library Association. Creature lovers may recall that in 2005, Rothenberg authored the bestselling Why Birds Sing (Basic Books).
The results have been captured live on compact disc. Whale Music can be heard at http://cdbaby.com/cd/davidrothenberg2, iTunes or www.thousandmilesong.com. To produce the new material, Rothenberg traveled from Hawaii to Russia to play his bass clarinet while recording the sounds of beluga, killer and humpback whales. A never-before-recorded Pete Seeger song, “The World’s Last Whale,” also debuts.
“I see this recording changing how we listen to the sea, leading us to appreciate beautiful and little-known sounds from the world’s watery depths,” Rothenberg said. ECM violinists Nils Økland and Michelle Makarski appear on some tracks. Rothenberg’s previous recordings include On the Cliffs of the Heart (New Tone Records, 1995) featuring percussionist Glen Velez and banjo player Graeme Boone. The work, praised by composer John Cage, was named a top ten release of 1995 by Jazziz. David Rothenberg can be reached via email at email@example.com.
NJIT Professor’s Timely Book Examines Great Depression and Modern Environmentalism
The Great Depression collided with a wave of natural disasters, including the Dust Bowl and devastating floods of the Ohio and Mississippi rivers. Recovering from these calamities—and preventing their reoccurrence—was a major goal of the New Deal. In Nature's New Deal: The Civilian Conservation Corps and the Roots of the American Environmental Movement (Oxford University Press, 2007), NJIT author and professor Neil M. Maher recounts the history of one of Franklin D. Roosevelt's boldest and most successful experiments, the Civilian Conservation Corps. Maher describes the organization as a turning point in national politics and in the emergence of modern environmentalism. Maher, an associate professor at NJIT, chairs the history department. Maher is available for interviews. Call him at 646-325-3704.
Indeed, Maher notes, Roosevelt addressed both the economic and environmental crises by putting Americans to work at conserving natural resources, through the Soil Conservation Service, the Tennessee Valley Authority, and the Civilian Conservation Corps (or CCC). The CCC created public landscapes—natural terrain altered by federal work projects—that helped environmentalism blossom after World War II, he says.
Millions of Americans devoted themselves to a new vision of conservation, one that went beyond the old model of simply maximizing the efficient use of natural resources, to include the promotion of human health through outdoor recreation, wilderness preservation, and ecological balance.
And yet, as Maher explores the rise and development of the CCC, he also shows how the critique of its campgrounds, picnic areas, hiking trails, and motor roads frames the debate over environmentalism to this day. From the colorful life at CCC camps, to political discussions in the White House and the philosophical debates dating back to John Muir and Frederick Law Olmsted, Nature's New Deal captures a key moment in the emergence of modern environmentalism.
Contact: Sheryl Weinstein, public relations director, NJIT (973-596-3436).