Nano Infrastructure Research Group

Nouns to Nano: Liberal arts graduate goes back to class to pursue her passion for nanotechnology research

Professor Hunain Alkhateb and Grace McMahen perform a nano simulation

Grace McMahen Rushing had earned her first bachelor's degree from the University of Mississippi before she discovered that nanomacterials research is both her passion and her niche.

“After receiving my English degree (with a minor in mathematics), I originally wanted to go to law school,” said the junior civil engineering major from Union. “But I changed my mind and decided to get a degree in engineering.”

Since then, Rushing has discovered that conducting experiments in UM's Nano Infrastructure Research Group, or NIRG, is truly a dream come true.

“My primary skill set lies in using AFM, or atomic force microscopy, to image various materials that we are working with, such as cement with nano additives, oil shale and several different kinds of polymers,” Rushing said. “This imaging allows us to understand the properties of the materials on a very small level, which will in turn aid us in predicting how the material will behave on a larger scale.”

Rushing is also in the process of learning how to use molecular dynamics to model these materials on a small scale to predict how they will react to various outside influences, such as temperature change or the presence of other materials. She assists Ahmed Al-Ostaz, Brevard Family Chair in Civil Engineering, professor of civil engineering and director of the research team. Collaborators include Alex Cheng, dean of the School of Engineering; A.M. Rajendran, chair and professor of mechanical engineering; and Hunain Alkhateb, assistant professor of civil engineering.

“In our laboratory, we design new materials and study the process of existing materials that can withstand extreme environments and improve the resilience of our nation's infrastructure against man-made threats, such as bomb blasts, fire or projectiles, and natural disasters: tornadoes, earthquakes and hurricanes,” Al-Ostaz said. “We are also preparing future engineers and scientists to better understand and meet both today's needs and tomorrow's challenges.”

In the past six years, NIRG researchers have received more than $8 million in grants from NASA, the Office of Naval Research, Department of Homeland Security, Mississippi Space Grant Consortium and North Carolina Agricultural & Technical State University/U.S. Army.

The group has studied materials at extreme sizes, from nanoscale to full structures; extreme distances, from oil and gas shales deep in the ground to space applications, including the International Space Station; extreme loading rates, from static blast to ballistic to hypervelocity impact; extreme temperatures, from freezing to boiling; and extreme times, from a fermisecond - or one quadrillionth of a second - to years.

The multifunctional materials merge modeling, designing and manufacturing new materials with actual testing of these products in simulated environments. Examples include materials that can resist blast loading with improved fire performance, and new materials and structures to enhance the performance of New Orleans' levees during extreme hurricane seasons.

“With the cement, for example, we are hoping that the nano additives will make it stronger and more durable, which will allow for less of it to be used when constructing a structure,&rdquo Rushing explained. &ldquoA smaller column made of cement that uses nano additives might support the same structure as a larger column that doesn't use those additives.

“The less cement used to achieve the same result will mean that less CO2 is emitted into the atmosphere, and the structure will have a smaller environmental impact as a whole.”

Another example, Rushing gave is polymers, some of which can be used as blast and fire-resistant coatings on buildings.

“These coatings would allow the people inside to safely exit the building without being harmed by shrapnel if there was an explosion,” she said. “They can also be used to coat rail cars carrying toxic chemicals and could prevent, or at least slow, the leakage of the chemicals if the car were punctured or damaged.”

New classes of nanomaterials - such as carbon nanotubes, nanofibers, nanowires, and quantum dots - are being assembled atom-by-atom, with various high-tech applications in mind, such as electronics, biomedicine, energy and environment.

“However, these materials are still very expensive and can only be produced at a relatively small quantity,” Al-Ostaz said.

To help protect the nation's critical infrastructure, including buildings, bridges, tunnels, transportation systems, pipelines, power transmission and communications systems, officials need nanomaterials that can be produced at low cost and in huge quantities.

“Fortunately, not all nanomaterials are man-made and expensive,” Al-Ostaz said. “There are abundant, naturally occuring and low-cost materials that are at or near nanosize, such as nanoclay, volcanic and fly ash, cellulose nanowhiskers and many carbon or silica-based minerals.”

Rushing originally decided to go to Ole Miss after high school because she fell in love with the campus after visiting and was offered generous scholarships, but she first decided as an English major. Now, as the secretary of the Ole Miss student chapter of the American Society of Civil Engineers, she has participated in the concrete canoe and steel bridge competitions as part of the Deep South Conference against schools such as LSU and Mississippi State.

“I also recently began volunteering at Habitat for Humanity with several other members of ASCE,” she said. “That has been a very educational and enjoyable adventure so far.”

While Rushing is excited and honored to be working with Al-Ostaz, she remains most proud of completing her thesis and graduating on time from the university the first time.

“I had been living in Oxford for a few years at that point, and, honestly, I just did not want to leave because it is a great town in which to live,” she said. “My experiences as both a student and a resident have been wonderful, and I especially enjoy the challenging course work in the civil engineering curriculum and thte pleasant atmosphere of both Ole Miss and Oxford.”

Rushing is the daughter of Michael and Susan McMahen of Union. She is married to Joshua Rushing of the Leake County community of Edinburg, who works in asset protection. Upon completion of her bachelor's degree, McMahen plans on getting her third degree from Ole Miss, a master's in civil engineering.