This research hypotheses is: (1) Indigenous microorganisms in the shallow aquifer at the FRC have the capability to reduce U(VI) and Tc(VII) but rates are limited by--Scarce electron donor, Low pH and potentially toxic metals, and High nitrate. (2) U(VI) and Tc(VII) reduction rates can be increased by--Successive donor additions, Raising pH to precipitate toxic metals, and Adding humics to complex toxic metals and serve as electron shuttles.

The primary objective of this report is to evaluate the rates and mechanisms of U(VI) reduction by microbial populations.

Analysis of the Genetic Potential and Gene Expression of Microbial Communities Involved in the In Situ Bioremediation of Uranium and Harvesting Electrical Energy from Organic Matter The primary goal of this research is to develop conceptual and computational models that can describe the functioning of complex microbial communities involved in microbial processes of interest to the Department of Energy. Microbial Communities to be Investigated: (1) Microbial community associated with the in situ bioremediation of uranium-contaminated groundwater; and (2) Microbial community that is capable of harvesting energy from waste organic matter in the form of electricity.

The purposes of this report are to: (1) to determine how flow and transport influence the distribution of U(VI) under field-relevant conditions and the transfer of reductive equivalents to the aqueous and solid phases by DMRB; and (2) to examine the solid-phase stability of bioreduced uranium phases--effects of mass transfer on reoxidation of U(IV) by O{sub 2} and other oxidants (e.g., NO{sub 3}{sup -}, denitrification products).

The objective of this report is to understand fundamental biogeochemical processes that would allow for the use of bioremediation approaches for cleaning up, managing, or understanding fate and transport at DOE's contaminated legacy waste sites.

The hypothesis of this report is Mobile radionuclides in low-permeability porous matrix regions of fractured saprolite can be effectively isolated and immobilized by stimulating localized in-situ biological activity in highly-permeable fractured and microfractured zones within the saprolite.

The summary of this report is: (1) biogenic flux increases as hydrologic residence time decreases; (2) reaction-based reactive transport modeling can capture this effect; (3) solid-phase Fe(III) bioreduction can be sustained at long residence times in natural sediments; and (4) long-term coupled Fe(III)/U(VI) bioreduction can be sustained in natural sediments.

Past studies demonstrate that complexation will limit abiotic and biotic U(VI) reduction rates and the overall extent of reduction. However, the underlying basis for this behavior is not understood and presently unpredictable across species and ligand structure. The central tenets of these investigations are: (1) reduction of U(VI) follows the electron-transfer (ET) mechanism developed by Marcus; (2) the ET rate is the rate-limiting step in U(VI) reduction and is the step that is most affected by complexation; and (3) Marcus theory can be used to unify the apparently disparate U(VI) reduction rate data and as a computational tool to construct a predictive relationship.

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This project goal is to identify genes and gene products required for microbial metal reduction: reductive dissolution of iron; reductive dissolution of manganese; reductive precipitation of selenium; reductive precipitation of uranium; and reductive precipitation of technetium.

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The projects application goals are to: (1) To understand bacterial stress-response to the unique stressors in metal/radionuclide contamination sites; (2) To turn this understanding into a quantitative, data-driven model for exploring policies for natural and biostimulatory bioremediation; (3) To implement proposed policies in the field and compare results to model predictions; and (4) Close the experimental/computation cycle by using discrepancies between models and predictions to drive new measurements and construction of new models. The projects science goals are to: (1) Compare physiological and molecular response of three target microorganisms to environmental perturbation; (2) Deduce the underlying regulatory pathways that control these responses through analysis of phenotype, functional genomic, and molecular interaction data; (3) Use differences in the cellular responses among the target organisms to understand niche specific adaptations of the stress and metal reduction pathways; (4) From this analysis derive an understanding of the mechanisms of pathway evolution in the environment; and (5) Ultimately, derive dynamical models for the control of these pathways to predict how natural stimulation can optimize growth and metal reduction efficiency at field sites.

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Slides from a presentation about the use of Thomson-Radiated Extreme X-ray (T-REX) sources for x-ray imaging and other applications.

This presentation by Keith Wipke at the 2007 DOE Hydrogen Program Annual Merit Review Meeting provides information about NREL's Controlled Hydrogen Fleet and Infrastructure Analysis Project.

This presentation by Margo Melendez at the 2007 DOE Hydrogen Program Annual Merit Review Meeting provides information about NREL's Hydrogen Demand & Infrastructure Rollout Scenario Analysis.

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Presentation on Hydrogen Codes and Standards.

Jim Ohi of NREL's presentation on Hydrogen Fuel Quality at the 2007 DOE Hydrogen Program Annual Merit Review and Peer Evaluation on May 15-18, 2007 in Arlington, Virginia.

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Plug-in Hybrid vehicles energy storage and drive cycle impacts, presented at the 7th Advanced Automotive Battery Conference.

This Photoelectrochemical Water Systems for Hydrogen Production presentation by the National Renewable Energy Laboratory's John Turner was given at the DOE Hydrogen Program's 2007 Annual Merit Review.