5 Matching Results

Search Results

Advanced search parameters have been applied.

The Development of New User Research Capabilities in Environmental Molecular Science: Workshop Report

Description: On August 1, and 2, 2006, 104 scientists representing 40 institutions including 24 Universities and 5 National Laboratories gathered at the W.R. Wiley Environmental Molecular Sciences Laboratory, a National scientific user facility, to outline important science challenges for the next decade and identify major capabilities needed to pursue advanced research in the environmental molecular sciences. EMSL’s four science themes served as the framework for the workshop. The four science themes are 1) Biological Interactions and Interfaces, 2) Geochemistry/Biogeochemistry and Surface Science, 3) Atmospheric Aerosol Chemistry, and 4) Science of Interfacial Phenomena.
Date: October 31, 2006
Creator: Felmy, Andrew R.; Baer, Donald R.; Fredrickson, Jim K.; Gephart, Roy E. & Rosso, Kevin M.
Partner: UNT Libraries Government Documents Department

Technetium Chemistry in HLW

Description: Tc contamination is found within the DOE complex at those sites whose mission involved extraction of plutonium from irradiated uranium fuel or isotopic enrichment of uranium. At the Hanford Site, chemical separations and extraction processes generated large amounts of high level and transuranic wastes that are currently stored in underground tanks. The waste from these extraction processes is currently stored in underground High Level Waste (HLW) tanks. However, the chemistry of the HLW in any given tank is greatly complicated by repeated efforts to reduce volume and recover isotopes. These processes ultimately resulted in mixing of waste streams from different processes. As a result, the chemistry and the fate of Tc in HLW tanks are not well understood. This lack of understanding has been made evident in the failed efforts to leach Tc from sludge and to remove Tc from supernatants prior to immobilization. Although recent interest in Tc chemistry has shifted from pretreatment chemistry to waste residuals, both needs are served by a fundamental understanding of Tc chemistry.
Date: June 6, 2005
Creator: Hess, Nancy J.; Felmy, Andrew R.; Rosso, Kevin M. & Yuanxian, Xia
Partner: UNT Libraries Government Documents Department

Computational Studies in Molecular Geochemistry and Biogeochemistry

Description: The ability to predict the transport and transformations of contaminants within the subsurface is critical for decisions on virtually every waste disposal option facing the Department of Energy (DOE), from remediation technologies such as in situ bioremediation to evaluations of the safety of nuclear waste repositories. With this fact in mind, the DOE has recently sponsored a series of workshops on the development of a Strategic Simulation Plan on applications of high perform-ance computing to national problems of significance to the DOE. One of the areas selected for application was in the area of subsurface transport and environmental chemistry. Within the SSP on subsurface transport and environmental chemistry several areas were identified where applications of high performance computing could potentially significantly advance our knowledge of contaminant fate and transport. Within each of these areas molecular level simulations were specifically identified as a key capability necessary for the development of a fundamental mechanistic understanding of complex biogeochemical processes. This effort consists of a series of specific molecular level simulations and program development in four key areas of geochemistry/biogeochemistry (i.e., aqueous hydrolysis, redox chemistry, mineral surface interactions, and microbial surface properties). By addressing these four differ-ent, but computationally related, areas it becomes possible to assemble a team of investigators with the necessary expertise in high performance computing, molecular simulation, and geochemistry/biogeochemistry to make significant progress in each area. The specific targeted geochemical/biogeochemical issues include: Microbial surface mediated processes: the effects of lipopolysacchardies present on gram-negative bacteria. Environmental redox chemistry: Dechlorination pathways of carbon tetrachloride and other polychlorinated compounds in the subsurface. Mineral surface interactions: Describing surfaces at multiple scales with realistic surface functional groups Aqueous Hydrolysis Reactions and Solvation of Highly Charged Species: Understanding the formation of polymerized species and ore formation under extreme (Hanford Vadose Zone and geothermo) conditions. By understanding ...
Date: April 18, 2006
Creator: Felmy, Andrew R.; Bylaska, Eric J.; Dixon, David A.; Dupuis, Michel; Halley, James W.; Kawai, R. et al.
Partner: UNT Libraries Government Documents Department

EMSL Geochemistry, Biogeochemistry and Subsurface Science-Science Theme Advisory Panel Meeting

Description: This report covers the topics of discussion and the recommendations of the panel members. On December 8 and 9, 2010, the Geochemistry, Biogeochemistry, and Subsurface Science (GBSS) Science Theme Advisory Panel (STAP) convened for a more in-depth exploration of the five Science Theme focus areas developed at a similar meeting held in 2009. The goal for the fiscal year (FY) 2011 meeting was to identify potential topical areas for science campaigns, necessary experimental development needs, and scientific members for potential research teams. After a review of the current science in each of the five focus areas, the 2010 STAP discussions successfully led to the identification of one well focused campaign idea in pore-scale modeling and five longer-term potential research campaign ideas that would likely require additional workshops to identify specific research thrusts. These five campaign areas can be grouped into two categories: (1) the application of advanced high-resolution, high mass accuracy experimental techniques to elucidate the interplay between geochemistry and microbial communities in terrestrial ecosystems and (2) coupled computation/experimental investigations of the electron transfer reactions either between mineral surfaces and outer membranes of microbial cells or between the outer and inner membranes of microbial cells.
Date: August 1, 2011
Creator: Brown, Gordon E.; Chaka, Anne; Shuh, David K.; Roden, Eric E.; Werth, Charles J.; Hess, Nancy J. et al.
Partner: UNT Libraries Government Documents Department