Dr. Susan Lehman has been awarded a National Science Foundation grant to study avalanches
Dr. Susan Lehman, Clare Boothe Luce Associate Professor of Physics, is a recent recipient of a grant from the National Science Foundation (NSF). She is Wooster’s 14th such awardee since 2006. Her research focuses on the inner workings of avalanches, specifically how the size of an avalanche is affected by how strongly the materials that compose it clump together. This phenomenon is called cohesion.
Cohesion in the materials that compose an avalanche — be it a snow-avalanche, a landslide or any other similar system — leads to a greater frequency of large, and often destructive, avalanches. When avalanches that are more cohesive occur, a greater amount of material is set in motion. Essentially, there are fewer avalanches overall but those that do occur are larger.
“Cohesion is what you don’t want to happen. That’s when you get a really catastrophic avalanche,” said Lehman. “That’s why we’re trying to understand what’s happening, because if your pile is normally [one height], but you have cohesion and it lets it build up [to a greater height], then all of a sudden you lose your cohesion, you’ve got a huge amount of mass that’s going to come sliding down… So understanding cohesion is really important.”
To understand the effects of cohesion, Lehman uses a cone-shaped pile of magnetized beads. By changing the strength of the magnetic field that holds all of the beads together and then dropping one bead at a time on the pile, Lehman and her associates are able to measure how great a mass is collected before an avalanche occurs and how great a mass that avalanche itself constitutes.
The data obtained from using this bead pile can then be extrapolated to other systems, such as landslides or snow avalanches.
“[I]n general, understanding the way that cohesion affects the distribution of avalanches should be universal, it shouldn’t depend on exactly the specifics of our bead-to-bead interaction,” said Lehman. “It should really fall over a wide range of systems.”
Lehman is working on this project with Dr. Karin Dahmen of The University of Illinois at Urbana-Champaign and College of Wooster Victor J. Andrew Professor Emeritus of Physics, Dr. Donald Jacobs. The three-year, $355,973 grant is to be split between Dahmen and Lehman.
The money will primarily cover the salaries of graduate students working on the project at The University of Illinois and students doing summer-research at the College of Wooster, equipment-related expenses (such as improvements to the bead pile) and travel expenses between the campuses. Additionally, once the research is complete, the funds will help in the coverage of expenses incurred by going to conferences to present their findings.
In addition to presenting the work to their peers, Lehman expects that journal articles will result from the data gathered. “I certainly would expect that several publications would come out of the grant,” she said.
This is not the first time that Lehman and her associates have applied for a grant from the NSF for this particular project. An earlier version of the proposal was submitted in Oct. 2011 but was denied. The current evolution of the grant was submitted in Feb. 2013.
Each proposal given to the NSF is reviewed by a team of scientists who then recommend to the NSF whether a grant ought to be awarded.
“[The process] is very competitive,” said Lehman. “Maybe 20-30 percent of grants get funded, so it is really important to use the feedback from the review and resubmit your proposal.”