If one were to drop a bag of sand from a high elevation, it would not bounce. Instead, the impact would splinter into a million shock waves throughout the sand particles.
This simple concept is the basis for a $186,000 grant awarded to a UB professor by the National Science Foundation to fund research on how such materials may apply to impact studies, including the protection of buildings from terrorist attacks.
Surajit Sen, associate professor of physics at UB, has been studying the propagation of impulses in soil for the past six years. His research began with the idea of using gentle impulses to detect buried landmines, which subsequently evolved into the much larger project of rethinking building design.
Sen's research, performed in March and April of this year, "rests on a simple design" of arranging grains of sand with varying sizes in the building's foundation. Such an arrangement, Sen said, would enable a shockwave to be absorbed efficiently and convert a sizeable portion of the absorbed energy into a less damaging form of energy.
"It's a very new theory," said Richard Gonsalves, chair of the physics department. "[The department] is very pleased."
The National Aeronautics and Space Administration latched onto Sen's project last July when NASA-affiliated professor Masami Nakagawa of the Colorado School of Mines and Dr. Juan Aqui invited him to lecture on impulse propagation studies. A test performed Nov. 14 by the group proved far more successful than their "overly conservative" estimates, according to Sen.
"The actual experiments," Sen explained, "show that absorption is far greater than what we have predicted as the minimum possible absorption." He noted that "generating a new idea of potential importance is fun, but it's even more fun if someone wants to do a reality check by performing a well-designed experiment in the laboratory."
Although Sen's six years of research were not focused on preventing building collapses caused by terrorist attacks, he said that prior incidents such as the U.S.S. Cole and the embassy bombings were still fresh in his mind.
Sen called receiving the NSF funding "the highest honor" because the foundation funds only a small number of single-investigator projects on theoretical studies.
"My reaction to getting this grant is that of great excitement. This is a serious recognition of the contributions, of the efforts, of the collaborators and of myself," he said.
Sen was born in Calcutta, India, where he earned his bachelor's of physics from Presidency College. He has conducted postdoctoral research at University of Minnesota and at Michigan State University.
Beyond granular physics, Sen is interested in studying dynamical phenomena in a variety of physical and biological systems. In addition, he is dedicated to applying his research to even the most rudimentary physics lessons.
"I am deeply interested in taking the lessons of physics research to the classrooms in our schools, and to the freshmen and sophomores," said Sen.
