The Air Force has long been interested in micro-scale air vehicles ?some as small as insects ?but it has been stymied by the lack of a suitable, compact power source. With $4.4 million from the Department of Defense's Multidisciplinary University Research Initiative, or MURI, the USC and Rice research team hopes to prove its concept valid within five years by producing a self-propelled prototype.
At Rice, geochemist Andreas Lüttge will spearhead the team's efforts to understand how the bacteria Shewanella oneidensis attach to and interact with anode surfaces inside the fuel cell. Anodes are the parts of fuel cells and batteries that gather excess electrons for harvesting. To optimize its design, the team must understand how bacteria transfer electrons to anode surfaces under a variety of conditions.
"There are three primary components in the system: the bacteria, the surface and the solution that the bacteria are digesting," said Lüttge, associate professor of earth science and chemistry. "Any change in one variable will affect the other two, and what we want to do is find out how to tweak each one to optimize the performance of the whole system."
Lüttge's participation in the program grew out of a decade-long collaboration with principal investigator Kenneth Nealson, USC's Wrigley Chair in Environmental Studies and Professor of Earth Sciences and Biological Sciences. Nealson helped pioneer the field of modern geobiology and the investigation of the genetic pathways that some microbes rely upon to maintain their respiratory metabolism in oxygen-poor environments. Shewanella oneidensis, one such bacterium, uses metals instead of oxygen to fully metabolize its food.
"Since this organism is cap