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Effective environmental management of DOE sites requires reliable prediction of reactive transport phenomena. A central issue in prediction of subsurface reactive transport is the impact of multiscale physical, chemical, and biological heterogeneity. Heterogeneity manifests itself through incomplete mixing of reactants at scales below those at which concentrations are explicitly defined (i.e., the numerical grid scale). This results in a mismatch between simulated reaction processes (formulated in terms of average concentrations) and actual processes (controlled by local concentrations). At the field scale, this results in apparent scale-dependence of model parameters and inability to utilize laboratory parameters in field models. Accordingly, most field modeling efforts are restricted to empirical estimation of model parameters by fitting to field observations, which renders extrapolation of model predictions beyond fitted conditions unreliable. The objective of this project is to develop a theoretical and computational framework for (1) connecting models of coupled reactive transport from pore-scale processes to field-scale bioremediation through a hierarchy of models that maintain crucial information from the smaller scales at the larger scales; and (2) quantifying the uncertainty that is introduced by both the upscaling process and uncertainty in physical parameters. One of the challenges of addressing scale-dependent effects of coupled processes in …

Remediation and long-term stewardship of uranium-contaminated sediments and groundwaters are critical problems at a number of DOE facilities and mining sites. Some remediation strategies based on in-situ bioreduction of U are potentially effective in significantly decreasing U concentrations in groundwaters. However, a number of basic processes require understanding in order to identify conditions more conducive to success of reduction-based U stabilization. Our current research targets several of these issues including: (1) effects of organic carbon (OC) forms and supply rates on stability of bioreduced U, (2) the roles of Fe(III)- and Mn(III,IV)-oxides as potential U oxidants in sediments, and (3) microbial community changes in relation to U redox changes. These issues were identified in our previous study on U bioreduction and reoxidation (Wan et al., 2005). Most of our studies are being conducted on historically U-contaminated sediments from Area 2 of the Field Research Center, Oak Ridge National Laboratory, in flow-through columns simulating in-situ field remediation.

Environmental nanoparticles are often poorly-crystalline or metastable structures, whose kinetics of formation and growth are poorly understood. Further, the sorption or growth of nanoparticles on mineral surfaces may control the mineral surface's reactivity and modify its ability to influence contaminant transport. Due to the characteristic length scale, a holistic understanding of the nucleation mechanisms and kinetics of nanoparticle formation on mineral surfaces is difficult to achieve with traditional methodology. In this work, our intent is to determine the molecular nature of nucleation on surfaces, the kinetics of surface nucleation and growth, and the effect of crystal surface topology using new synchrotron-based techniques. We have approached these objectives by: (1) combining state-of-the-art crystal-truncation rod diffraction (CTR) and grazing incidence x-ray absorption fine structure spectroscopy (GIXAS) techniques to investigate the three-dimensional molecular-scale geometry of silicate monomer sorption on the r-plane of hematite; and (2) developing a new grazing-incidence small angle x-ray scattering (GISAXS) setup at SSRL (0.08 nm{sup -1} < q < 8 nm{sup -1}) to explore the initial development of environmental nanoparticles on various mineral surfaces. This study also includes complementary techniques such as atomic force microscopy (AFM), bulk SAXS, dynamic light scattering (DLS), XRD, and TEM.

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The overall objective of this project is to examine the activity of nonspecific phosphohydrolases present in naturally occurring subsurface microorganisms for the purpose of promoting the immobilization of radionuclides through the production of uranium [U(VI)] phosphate precipitates. Specifically, we hypothesize that the precipitation of U(VI) phosphate minerals may be promoted through the microbial release and/or accumulation of PO4 3- as a means to detoxify radionuclides and heavy metals. An experimental approach was designed to determine the extent of phosphatase activity in bacteria previously isolated from contaminated subsurface soils collected at the ERSP Field Research Center (FRC) in Oak Ridge, TN. Screening of 135 metal resistant isolates for phosphatase activity indicated the majority (75 of 135) exhibited a phosphatase-positive phenotype. During this phase of the project, a PCR based approach has also been designed to assay FRC isolates for the presence of one or more classes of the characterized non-specific acid phophastase (NSAP) genes likely to be involved in promoting U(VI) precipitation. Testing of a subset of Pb resistant (Pbr) Arthrobacter, Bacillus and Rahnella strains indicated 4 of the 9 Pbr isolates exhibited phosphatase phenotypes suggestive of the ability to bioprecipitate U(VI). Two FRC strains, a Rahnella sp. strain Y9602 and …

Plutonium has a long half-life (2.4 x 104 years) and is of concern because of its chemical and radiological toxicity, high-energy alpha radioactive decay. A full understanding of its speciation and interactions with environmental processes is required in order to predict, contain, or remediate contaminated sites. Under aerobic conditions Pu is sparingly soluble, existing primarily in its tetravalent oxidation state. To the extent that pentavalent and hexavalent complexes and small colloidal species form they will increase the solubility and resultant mobility from contamination sources. There is evidence that in both marine environments and brines substantial fractions of the plutonium in solution is present as hexavalent plutonyl, PuO2 2+.

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The overall goal of this project is to develop and test a thermodynamic network model for predicting the effects of substrate additions and environmental perturbations on microbial growth, community composition and system geochemistry. The hypothesis is that a thermodynamic analysis of the energy-yielding growth reactions performed by defined groups of microorganisms can be used to make quantitative and testable predictions of the change in microbial community composition that will occur when a substrate is added to the subsurface or when environmental conditions change.

Poster/flyer advertising Gutterth Live XXVI concert featuring Zanzibar Snails, Geistheistler and Dirty Water Disease on September 19, 2000, at J&J's Pizza in Denton, TX.

Poster for the play Blues on 125th Street, performed by the Third World Players, written by Bob Ray Sanders, and directed by Curtis L. King. The play was performed on November 19, 1978 at the Dallas Convention Center Theater.

Front: Text highlights the strategic concept that guided the Western Allies to victory in Europe. Map shows German occupied territory as of 7 Dec 1941 in western Europe and North Africa. Back: Text and illustration highlight the postwar job as a threefold task: Speedily demobilize those in uniform who want to return to civilian life, maintain and supply occupation forces, and provide for peacetime military strength to help ensure world security.

Front: Text describes action on various war fronts: Americans Cross Rhine; New Philippine Landings; Allies in Mandalay. Maps: Red Army menaces Oder line, Road to Mandalay, Mindanao P.I. Includes distance scale from Linz east to Berlin and from Zehden west to Berlin. Back: Map of the Pacific and the Far East. Inset maps: Ryukyu Retto, Okinawa, Saipan, Iwo-Jima, Paramushiru, Chisima Retto (Kurile Is.).

Front: Text describes action on various war fronts: Allies press western front Offensive; Manila battle continues - B-29's active; Soviets make new crossings Maps: Western Front, Soviet Salient, U.S. troops continue to clear Manila. Back: Text and illustration and photographs highlight the role of Military Police.

Front: Text highlights action on various war fronts: France ; Italy ; Pacific ; Eastern Front ; Balkans. Inset maps: The advance beyond Rome ; Europe ; The Normandy coast ; China. Photographs: American assault troops move ashore in northern France ; Canadians with bicycles disembark from an infantry landing craft. Back: Map of Germany and adjacent areas shows railroads, superhighways, rivers, and mountains.

Front: Text describes action on various war fronts: Sicily, Air offensive, Russia, New Georgia, New Guinea, Aleutians, Submarines. Includes list of senior commanders in the Invasion of Italy. Maps: New Georgia Islands; American 7th army positions in Licata and Vittoria Italy. Inset map: Italy and surrounding islands. Illustration: Landing on the underside [Allied air attack on ships unloading military cargo on the beaches of Southern Sicily]. Back: Text and color illustrations include various methods of enemy gas applications.

Front: Text describes action on various war fronts: Tunisia -- Southwest Pacific -- Russia -- Mediterranean. Large world map is keyed to text and illustrates time zones around the world. Inset maps show Allied drive in Tunisia -- Japanese controlled areas throughout the Southwest Pacific. Includes photographs: Helping Rommel's run [puppy stationed atop a Vickers machine gun] -- So he can fight (Staff Sergt. Hollers clerks at the San Angelo AAF Bombardier School in Texas) -- Blimp training. Back: Tunisia, map with inset showing location of Tunisia in the Mediterranean area.

Front: Text describes action on various fronts: Solomons, New Hebrides, New Guinea, Aleutians, Far Eastern waters, Russia, Mediterranean, Western Europe. Large world map is keyed to text and illustrates time zones around the world. Inset maps show Guadalcanal Island, Tulagi; Russian front. Includes photographs: Alaska road in use by December (construction of the Alaska Defense Highway); Zero fighter; in the Solomons; German mobile gun; Insect protection. Back: Airborne Command. 12 photographs with descriptive text and explanation of the role of airborne troops.

Advertisement of a baseball game, Ellington Field vs. Southern Select, to be played at the Cleveland Diamond field, on Sunday April 19, 1942 at 2:30 p.m. The names of the players of each team are shown in the poster. The poster also contains advertisements.