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HEALTH -- Environmental respiration risks . . .
Little is known about the toxicological effects of inhaling airborne ultrafine particles, but that may soon change because of research by a team led by Mengdawn Cheng of Oak Ridge National Laboratory. Of particular interest is the interaction of human tissue and particles 1 to 100 nanometers in size that are byproducts of exhaust from internal combustion engines and other sources -- including new manmade nanophase materials. Cheng's team is developing instruments and techniques to more accurately measure these nanoparticles and model cells to understand biological responses to exposure. Through better exposure characterization, researchers hope to perform risk analyses from which safety standards can be established. Collaborators include Wright Patterson and Elgin Air Force bases, National Institute for Occupational Safety and Health, Rice University, Pacific Northwest National Laboratory and Lovelace Respiratory Research Institute. The research is funded by the departments of Energy and Defense. ]
AUTOMOBILES -- Sparking a revolution . . .
Tomorrow's engines could boast greater fuel efficiency and lower emissions because of a system being developed by Oak Ridge National Laboratory. New ORNL test data shows that spark-assisted homogeneous charge compression ignition has a 12 percent improvement in fuel efficiency and a 95 percent reduction in nitrogen oxide emissions compared to conventional spark ignition. ORNL plans to marry this concept with the rotating arc spark plug, which was invented at ORNL. The new engine will be a hybrid of conventional spark ignition and the compression ignition process that takes place in spark and diesel engines and normally results in engine knock. The key to increased efficiency is that burning of the fuel takes place faster inside the cylinder, allowing energy extraction for the full piston stroke. Controlling this process and eliminating the knocking sound has always been difficult, but the addition of spark assist using the rotating arc spark plug should improve stability and transient control.
CHEMISTRY -- Sophisticated separations . . .
A one-step process to separate cesium and strontium from caustic waste could possibly lead to significant savings in processing, transportation and storage of some 34 million gallons of nuclear waste at the Savannah River Site. Laetitia Delmau of Oak Ridge National Laboratory's Chemical Sciences Division is developing a process concept that involves adding crown ether and carboxylic acid to the solvent used in the caustic-side solvent extraction (CSSX) process. The CSSX process was developed at ORNL to remove cesium from alkaline nitrate waste and will be used at the Savannah River Site to reduce the volume of high-level waste. This waste was generated over the last 50-plus years in the production of materials for the U.S. nuclear weapons program. If Delmau's new approach proves feasible it would extend the CSSX capabilities by enabling the process to remove cesium and strontium in one step. This could possibly lead to additional cost savings and waste volume reduction. Ultimately, researchers hope to develop a process to extract uranium, neptunium and plutonium as well. The project is funded by the DOE Environmental Management Science Program.