Logs confiscated by police at a Texas murder scene and the work of a scientist at Oak Ridge National Laboratory may help put a killer behind bars. Using a technique called laser-induced breakdown spectroscopy, Madhavi Martin obtained "chemical fingerprints" from a partially burned log at the crime scene and compared them to those of logs that had been placed by the suspect in a fireplace. "We used our laser technique to determine the elemental makeup based on heavy metals and other trace elements to evaluate whether the two sets of logs could have come from the same tree," Martin said. She and the University of Tennessee's Henri Grissino-Mayer concluded that the two samples matched. Had the wood come from different trees the chemical fingerprints would have been different. Laser-induced breakdown spectroscopy is a technique that Martin and ORNL's Stan Wullschleger originally used for carbon sequestration applications such as determining the amount of carbon in soil. Since then, the technique has also proved useful for identifying chemical fingerprints in bones and for detecting counterfeit currency. The research is funded by the Department of Justice and ORNL's Laboratory Directed Research and Development program.
NANOSCIENCE -- On a butterfly's wings . . .
Microscopic images that are now achievable at single-nanometer scales usually depict advanced materials or other ordered, inorganic substances. However, a team of researchers from Oak Ridge National Laboratory (S.V.Kalinin) and North Carolina State University (A. Gruverman) have applied scanning probe microcopy to living biosystems -- in this case to look at the structure of a butterfly's wing. The 5-nanometer resolution images, obtained with a technique called atomic force acoustic microscopy, depict the infinitesimally complex structures that underlie the functionality and delicate spectacle of the flying insect's wing. Using the instrument, researchers can see nanometer-sized structural elements at resolutions that roughly equal the size of a DNA molecule. ORNL researcher Sergei Kalinin says the butterfly images are just a proof of concept -- the new strides in advanced scanning probe microscopies will eventually provide a "wonderful tool" for understanding, as well as viewing, properties and functionality of living biosystem's on length scales from macroscopic to molecular.
SENSORS -- Advanced fuel cells . . .
Miniature optical sensors developed at Oak Ridge National Laboratory could speed the development of fuel cells to power vehicles, buildings and machines. The ORNL sensors are extremely accurate, reliable and fast-responding, making them ideal for next-generation fuel cells, according to Steve Allison of ORNL's Engineering Science & Technology Division. Key to the success of the sensors is their ability to measure temperature and moisture within an operating fuel cell. This allows developers of proton exchange membrane fuel cells to verify computer models of fuel cell stocks to optimize performance. Furthermore, real-time diagnostic sensors allow designers to increase stack power density by reducing operating margins and quickly identify the development of hot spots that could cause catastrophic failure. The new sensors, which combine fiber optics with luminescence technology, feature temperature accuracy to within plus- or minus-half a degree Celsius, humidity accuracy within 1 percent and temperature response time of one-tenth of a second. The work is funded by the Department of Energy Office of Energy Efficiency and Renewable Energy's Office of Hydrogen, Fuel Cells and Infrastructure Program.
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