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Chemical engineering meeting spotlights advances in health, energy, technology

Robert Madix, professor emeritus in School of Engineering, honored with daylong symposium at annual conference

Robert Madix

Robert Madix

BY DAVID ORENSTEIN

Stanford researchers presented new developments in health, clean energy, nanotechnology and other fields recently at the annual meeting of the American Institute of Chemical Engineers (AIChE) in San Francisco.

"The papers presented come from many different departments in several schools and institutions at Stanford, reflecting that research that crosses traditional boundaries within universities is essential to tackling today's most challenging problems," said Jim Plummer, dean of the School of Engineering.

Founded in 1908, AIChE represents more than 40,000 chemical engineers in 92 countries. The meeting, held Nov. 13-17, focused on new research in chemical and biomolecular engineering, as well as advances in nanotechnology.

On Nov. 13, graduate student John Kirkwood from the research group of chemical engineering Professor Gerald Fuller presented new findings on the molecular details that may underlie Alzheimer's disease. Kirkwood described experiments showing how chains of amino acids, called amyloid beta-peptides, interact with lipids and water. Such interactions may explain how these peptides accumulate on neural cell membranes in brain tissue and disrupt the cell's inner workings, causing cellular malfunction and incurable dementia.

Fuel cell advances

In the field of alternative energy, several Stanford speakers explored new ways to make hydrogen fuel cell technology more practical and economically viable. One major issue involves safety. Hydrogen compressed in tanks is potentially explosive, and solid metal hydrides are too heavy, too slow to charge or require too much heat to be used in fuel cells. To overcome the problem, an interdisciplinary Stanford group led by materials science and engineering Professor Bruce Clemens and chemistry Professor Hongjie Dai is looking at the possibility of storing hydrogen in carbon nanotubes, which may be safer than conventional storage materials. On Nov. 15, engineering graduate student Yong-Won Lee presented research showing that carbon nanotubes peppered with palladium can store four times more hydrogen than untreated nanotubes.

Two other presentations from the research group of mechanical engineering Associate Professor Juan Santiago dealt with overcoming some of the technical hurdles that make fuel cells unreliable and expensive compared to conventional fuel systems or electric batteries. One factor reducing fuel cell efficiency is that they require moving small quantities of liquid fuel, water and air through labyrinths of tiny channels to or from the sites where reactions occur. To overcome this drawback, Santiago and his colleagues have proposed incorporating small "electro-osmotic" pumps that use electric fields rather than moving parts to push liquids around. On Nov. 15, graduate student Shawn Litster described how these pumps could redistribute water supplies throughout the cell so that no section would dry out or flood. Graduate student Cullen Buie also explained how similar pumps could be use to deliver significant amounts of hydrogen-rich methanol fuel with high reliability and very low power.

Electronics and nanotechnology

On Nov. 14, Charles Musgrave, assistant professor of chemical engineering, discussed his research on integrating amino acids into nanoscale electronic devices. Musgrave's group focuses on using amino acids as nanoscale building blocks to make hybrid bioinorganic circuits and biological sensors. Many researchers, including several at Stanford, are looking at the possibility of using a variety of organic molecules in electronic circuits. Musgrave is focusing on amino acids, the building blocks of proteins, because they appear to be particularly versatile in giving engineers options for tuning these devices for different applications.

On Nov. 16, electrical engineering Assistant Professor Peter Peumans discussed improving the energy efficiency of organic light-emitting diodes (OLEDs), a carbon-based technology now being used in futuristic displays on mobile phones and other electronic devices. Although OLEDs are pretty, they also are very inefficient, reflecting up to 80 percent of the light they emit, which means that most OLED light doesn't reach the eye. Making OLEDs bright enough to see requires a large current, which drains battery power in portable devices. Peumans explained how his group achieved some success by adding a special mirror structure that controls the emission of light and therefore wastes less energy.

Madix honored

A highlight of the AIChE conference was the Nov. 17 daylong symposium honoring Robert J. Madix, the Charles Lee Powell Professor in the School of Engineering, Emeritus. The symposium, which focused on the chemical reactivity of molecules on solid surfaces, featured several speakers, including Madix, who described how studies of single metallic crystals have yielded new understandings about the movement and interaction of chemicals during a variety of reactions.

"Professor Madix's work has paved the way for the discovery of high-performance catalysts and has opened new vistas as to how one thinks about chemical reactivity in general," said Channing Robertson, the Ruth G. and William K. Bowes Professor in the School of Engineering and senior associate dean for faculty and academic affairs at the school. "He has educated and trained a new generation of pioneers in this important area. His impact has been and will continue to be substantial in such applications as fuel cells, chemical synthesis and novel materials."

David Orenstein is the communications and public relations manager at the Stanford School of Engineering.