NANOSCIENCE -- Atom-scale switch . . .
?ORNL researchers performing basic research have discovered a carbon nanotube-based system that functions like an atom-scale switch. Their approach is to perform first-principles calculations on positioning a molecule inside a carbon nanotube to affect the electronic current flowing across it. The result is an electrical gate at the molecular level: In one position, the molecular gate is open, allowing current through; in another position, the gate is closed, blocking the current. In a silicon chip, the gate is a silicon oxide barrier within the structure of the chip. In the ORNL model, the gate is a short molecule --encapsulated inside the carbon nanotube-- that is about one nanometer in size, or three orders of magnitude smaller than a silicon chip. The paper is slated to appear in the Feb 2 Physical Review Letters.
[Contact: Bill Cabage, (865) 574-4399; cabagewh@ornl.gov]
ENERGY -- Microbial cost savings . . .
A tiny microbe may hold the key to simpler, lower-cost production of ethanol from biomass sources such as trees, grasses and cornstalks. Oak Ridge National Laboratory researchers are studying a bacterium known as Clostridium thermocellum, which has the ability to both degrade cellulose -- cellulose makes up the cell walls of plants -- into sugars and then ferment these sugars into alcohol, or ethanol. Today's production methods involve a costly, multi-step, enzyme-and-yeast-based process that would price the fuel at more than $2.20 per gallon. A group of ORNL researchers headed by Jonathan Mielenz is studying gene expression in this microbe to determine how these enzymatic functions are performed, revealing strategies for further reducing the cost of ethanol production. Within five years, researchers hope to demonstrate their process enhancements on an industrial scale.
[Contact: Larisa Brass, (865) 574-4163; brasslm@ornl.gov]
FORENSICS -- Dead giveaway . . .
Decompositional odors released from corpses in clandestine graves are providing a chemical fingerprint that could help law enforcement officials find these burial sites and provide evidence that ultimately points to the victim's killer. A team led by Arpad Vass, a forensics expert in Oak Ridge National Laboratory's Biosciences Division, started by identifying 478 specific volatile compounds associated with burial decomposition and narrowed these down to the top 30 in order of perceived importance for finding buried bodies. The project, begun four years ago, identifies the "odor signature" unique to human burial decomposition and could lead to improved cadaver dog training and possibly to a portable instrument that could help locate human remains. The research, performed with assistance from the University of Tennessee's Department of Anthropology and the Anthropological Research Facility, is funded by the FBI's Counterterrorism and Forensic Science Research Unit.
[Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov]
ENERGY -- Hot savings . . .
Homeowners could see their electric bills reduced considerably with Oak Ridge National Laboratory's integrated heat pump. The unit, which combines water heating with heating and cooling, dehumidification and ventilation functions, can use 50 percent less energy than standard heat pumps and water heaters. The unit's energy savings come primarily from hot water provided at heat pump efficiencies, said Richard Murphy, a researcher in ORNL's Building Technologies Program. The unit also benefits from the use of variable speed components that have operating rates that can be adjusted to meet current loads efficiently. A number of other factors, including the availability of mass-produced products such as brushless permanent magnet motors for compressors and fans, are seen as keys to the success of this effort. The goal of the project, funded by the Department of Energy's Office of Energy Efficiency and Renewable Energy, is to attract a commercial manufacturer by 2008.
[Contact: Ron Walli, (865) 576-0226; wallira@ornl.gov]
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