Chakraborty says that using this data she and Bi constructed a theory that explains how the solid is being formed. "It's possible that if there was no friction between the discs that they would have been able to slide past each other and not get jammed," says Chakraborty. "We now are performing computer simulations to see if shear jamming will occur without friction."
In an abstract written in 2008 in Jamming of Granular Matter, Chakraborty and Robert P. Behringer of Duke University explained that jamming is the extension of the concept of freezing to the transition from a fluid state to a jammed state. Understanding jamming in granular systems, they say, is important from a technological, environmental, and basic science perspective. A jamming of grains in silos cause catastrophic failures. Avalanches are examples of unjamming, which need to be understood in order to prevent and control, such as the avalanche that killed pro skier Jamie Pierre on November 13, 2011.
Shearing is a major force in nature, explains Chakraborty. When wind blows over the earth, shearing occurs in the sand. Understanding what shear does, she says, is very important.
"We have a very good theoretical framework as to how water behaves, or ice or air," says Chakraborty. "We don't have any fundamental theoretical framework to predict how sand behaves when the wind is blowing fast or slow."
This information coul
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