NASA has awarded nearly $1 million in grants for combustion research in microgravity to scientists at the University of California, Davis. The researchers will take advantage of NASA facilities including drop towers and a KC-135 airplane, dubbed "the Vomit Comet" by its users, that makes a series of dives and climbs to simulate weightlessness. Removing gravity from a combustion experiment makes it easier to study other effects. If the airplane and drop-tower experiments are successful, they may lead to grants for experiments on the space shuttle or the International Space Station. A $460,000 grant was awarded to Zuhair Munir, interim Dean of the College of Engineering, and Ben Shaw, of the Department of Mechanical and Aeronautical Engineering, to study the effects of electric fields on self-propagating combustion synthesis under microgravity conditions. A $395,000 grant was awarded to Ralph Aldredge, of the Department of Mechanical and Aeronautical Engineering, to research flame propagation in low-intensity turbulence under microgravity. Both grants are for four years. "We are delighted to receive two of the 28 NASA grants given nationwide. These studies will help provide a better understanding of the fundamental aspects of combustion, as an energy-releasing process and as a means to synthesize novel materials," said Munir. Munir and Shaw's team will design experiments to be carried on the NASA airplane, which flies a roller-coaster series of dips and climbs to create weightlessness for up to 25 seconds at a time. On each flight day, the plane makes at least 40 such maneuvers. Munir's graduate students will begin conducting experiments aboard the plane in the spring of 2001. Munir's laboratory studies a method called self-propagating high-temperature combustion synthesis. Rather than heating a mix of raw materials in a furnace, the process takes advantage of heat released by the reaction to generate a combustion wave front that passes rapidly through the reactants, forming the new material. The researchers found that by passing an electrical current through the reaction mixture, they could make existing reactions more efficient and create new materials with unique properties. "A process that takes four hours in a furnace takes seconds in an electric field, and we can make materials that could not be made otherwise," said Munir. The novel ceramic and composite materials created in this way have applications ranging from electronics to high-temperature structural materials and thermal barrier coatings, which could be used, for example, as heat shields on spacecraft. Munir's group has obtained several U.S. patents for its work in this area. Nanomaterials, which can be made only by this process, have received considerable attention, according to Munir. These are composed of extremely small crystals (around a millionth of a centimeter), much smaller than those found in ordinary materials. Nanomaterials can have unique properties, such as extreme hardness, said Munir. Munir's team thinks that the role of the electrical field includes the "electron wind effect," which imparts additional energy to diffusing atoms, and he and his students are investigating this aspect under an existing National Science Foundation grant. Because of the complex effects involved, they want to carry out experiments in an environment without one major complicating factor -- gravity. The team's planned research work includes collaboration with scientists in Canada and Europe. A Canadian-based company, Guigne International, is supplying a prototype reaction cell that Munir's laboratory will modify to use on the plane. Other collaborators include the European Space Agency and Daimler-Chrysler Corporation. Aldredge's laboratory studies combustion and moving flames as they propagate through a special chamber. A flame traveling through the chamber can be flat, but can suddenly become unstable, speeding up and releasing more energy, said Aldredge. The research has implications for the design of car engines, jet engines, and for a new technology called pulse-detonation engines. "We want to know the cause of this instability and how it can be controlled," said Aldredge. The researchers have already found that sound waves can be used to cause or to suppress instability. Aldredge's laboratory will use drop towers at the NASA Glenn Research Center in Ohio to carry out their experiments, with each drop providing about two seconds of microgravity. "We need to establish a flat flame first, and you can only reliably do that in microgravity," said Aldredge. Drop tower experiments are expected to begin in 2002. Editor's Note: Pictures of the KC-135 in flight, and of weightless experiments in progress, are available. Contact Andy Fell for details. Editor's Note: For more information on the NASA KC-135 and other microgravity facilities, visit these web sites. -- Microgravity Research Program, http://microgravity.msfc.nasa.gov -- Microgravity Facilities, http://microgravity.nasa.gov/mf.html -- KC-135 Zero Gravity Trainer, http://zeta.lerc.nasa.gov/kjenks/kc-135.htm