Search Results

A DSpace Foundation for a Teaching and Research Commons: The Metadata Education and Research Information Commons

Description: Poster presented at the 2007 International Conference on Open Repositories. This poster discusses the Metadata Education and Research Information Commons (MERIC). MERIC originated from an action plan of the Library of Congress and addresses the need to prepare future information professionals to organize and provide access to digital resources.
Date: January 2007
Creator: Hsieh-Yee, Ingrid; Moen, William E.; Vellucci, Sherry L. & Benton, Bryce
Partner: UNT College of Information

Integrating Controlled Vocabularies into Cultural Heritage Digital Collections: The Portal to Texas History Experience [Poster]

Description: Poster presented at the 2007 ASIS&T Annual Conference. This poster describes the University of North Texas (UNT) Libraries' digital libraries implementations experience. It discusses various scenarios and strategies for integrating controlled vocabularies in the uncontrolled digital library world.
Date: 2007
Creator: Alemneh, Daniel Gelaw; Phillips, Mark Edward & Belden, Dreanna
Partner: UNT Libraries

Adherence and the Medical Management of HIV/AIDS: Stress and Coping

Description: This poster investigates the association of medical adherence to perceived stress, maladaptive coping behaviors, and medical variables in a sample of HIV+ adults.
Date: November 5, 2007
Creator: Hua, William Q.; Vosvick, Mark A. & Chng, Chwee-Lye
Partner: UNT Center for Psychosocial Health Research

Parabolic Trough Receiver Heat Loss Testing (Poster)

Description: Parabolic trough receivers, or heat collection elements (HCEs), absorb sunlight focused by the mirrors and transfer that thermal energy to a fluid flowing within them. Thje absorbing tube of these receivers typically operates around 400 C (752 F). HCE manufacturers prevent thermal loss from the absorbing tube to the environment by using sputtered selective Cermet coatings on the absorber and by surrounding the absorber with a glass-enclosed evacuated annulus. This work quantifies the heat loss of the Solel UVAC2 and Schott PTR70 HCEs. At 400 C, the HCEs perform similarly, losing about 400 W/m of HCE length. To put this in perspective, the incident beam radiation on a 5 m mirror aperture is about 4500 W/m, with about 75% of that energy ({approx} 3400 W/m) reaching the absorber surface. Of the 3400 W/m on the absorber, about 3000 W/m is absorbed into the working fluid while 400 W/m is lost to the environment.
Date: March 1, 2007
Creator: Price, H.; Netter, J.; Bingham, C.; Kutscher, C.; Burkholder, F. & Brandemuehl, M.
Partner: UNT Libraries Government Documents Department

The Center for Environmental Kinetics Analysis: an NSF- and DOE-funded Environmental Molecular Science Institute (EMSI) at Penn State

Description: Physicochemical and microbiological processes taking place at environmental interfaces influence natural processes as well as the transport and fate of environmental contaminants, the remediation of toxic chemicals, and the sequestration of anthropogenic CO2. A team of scientists and engineers has been assembled to develop and apply new experimental and computational techniques to expand our knowledge of environmental kinetics. We are also training a cohort of talented and diverse students to work on these complex problems at multiple length scales and to compile and synthesize the kinetic data. Development of the human resources capable of translating molecular-scale information into parameters that are applicable in real world, field-scale problems of environmental kinetics is a major and relatively unique objective of the Institute's efforts. The EMSI team is a partnership among 10 faculty at The Pennsylvania State University (funded by the National Science Foundation Divisions of Chemistry and Earth Sciences), one faculty member at Juniata College, one faculty member at the University of Florida, and four researchers drawn from Los Alamos National Laboratory, Pacific Northwest National Laboratory, and Lawrence Berkeley National Laboratory (funded by the Department of Energy Division of Environmental Remediation Sciences). Interactions among the applied and academic scientists drives research approaches aimed toward solving important problems of national interest. The Institute is organized into three interest groups (IGs) focusing on the processes of dissolution (DIG), precipitation (PIG), and microbial reactions at surfaces (BIG). Some of the research activity from each IG is highlighted to the right. The IGs interact with each other as each interest group studies reactions across the molecular, microscopic, mesoscopic and, in most cases, field scales. For example, abiotic dissolution and precipitation reactions of Fe oxides as studied in the Dissolution IG provides the baseline for kinetic behavior as the BIG researches the interaction of microorganisms with these ...
Date: April 19, 2007
Creator: Brantley, S. L.; Burgos, William D.; Dempsey, Brian A.; Heaney, Peter J.; Kubicki, James D.; Lichtner, Peter C. et al.
Partner: UNT Libraries Government Documents Department

Isotopic Tracers for Biogeochemical Processes and Contaminant Transport: Hanford, Washington

Description: Our goal is to use isotopic measurements to understand how contaminants are introduced to and stored in the vadose zone, and what processes control migration from the vadose zone to groundwater and then to surface water. We have been using the Hanford Site in south-central Washington as our field laboratory, and our investigations are often stimulated by observations made as part of the groundwater monitoring program and vadose zone characterization activities. Understanding the transport of contaminants at Hanford is difficult due to the presence of multiple potential sources within small areas, the long history of activities, the range of disposal methods, and the continuing evolution of the hydrological system. Observations often do not conform to simple models, and cannot be adequately understood with standard characterization approaches, even though the characterization activities are quite extensive. One of our objectives is to test the value of adding isotopic techniques to the characterization program, which has the immediate potential benefit of addressing specific remediation issues, but more importantly, it allows us to study fundamental processes at the scale and in the medium where they need to be understood. Here we focus on two recent studies at the waste management area (WMA) T-TX-TY, which relate to the sources and transport histories of vadose zone and groundwater contamination and contaminant fluid-sediment interaction. The WMA-T and WMA-TX-TY tank farms are located within the 200 West Area in the central portion of the Hanford Site (Fig. 2). They present a complicated picture of mixed groundwater plumes of nitrate, {sup 99}Tc, Cr{sup 6+}, carbon tetrachloride, etc. and multiple potential vadose zone sources such as tank leaks and disposal cribs (Fig. 3). To access potential vadose zone sources, we analyzed samples from cores C3832 near tank TX-104 and from C4104 near tank T-106. Tank T-106 was involved in a ...
Date: April 19, 2007
Creator: DePaolo, Donald J.; Christensen, John N.; Conrad, Mark E. & Dresel, and P. Evan
Partner: UNT Libraries Government Documents Department

Mechanistically-Based Field-Scale Models of Uranium Biogeochemistry from Upscaling Pore-Scale Experiments and Models

Description: 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 heterogeneous porous media is the problem-specificity of solutions. Much effort has been aimed at developing generalized scaling laws or theories, but these require restrictive assumptions that render them ineffective in many real problems. We propose instead an approach that applies physical and numerical experiments at small scales (specifically the pore scale) to a selected model system in order to identify the scaling approach appropriate to that type of problem. Although the results of such studies will generally not be applicable to other broad classes of problems, we believe that this approach (if applied over time to many types of problems) ...
Date: April 19, 2007
Creator: Scheibe, Tim; Tartakovsky, Alexandre; Wood, Brian & Seymour, Joe
Partner: UNT Libraries Government Documents Department

Mesoscale Biotransformation of Uranium: Influences of Organic Carbon Supply Rates and Sediment Oxides

Description: 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.
Date: April 19, 2007
Creator: Tokunaga, Tetsu; Wan, Jiamin; Kim, Yongman; Daly, Rebecca; Brodie, Eoin; Firestone, Mary et al.
Partner: UNT Libraries Government Documents Department

Molecular-Level Investigations of Nucleation Mechanisms and Kinetics of Formation of Environmental Nanoparticles

Description: 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.
Date: April 19, 2007
Creator: Jun, Young-Shin & Waychunas, Glenn A.
Partner: UNT Libraries Government Documents Department

Promoting Uranium Immobilization by the Activities of Microbial Phosphatases

Description: 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 a Bacillus sp. strain Y9-2, were further characterized. The Rahnella sp. exhibited enhanced phosphatase activity relative to the Bacillus sp. Whole-cell enzyme assays identified a pH optimum of 5.5, and inorganic phosphate accumulated in pH 5.5 synthetic groundwater (designed to mimic FRC conditions) incubations of both strains in the presence of a model organophosphorus substrate provided as the sole C and P source. Kinetic experiments showed that these two organisms can grow in the presence of 200 μM dissolved uranium and that Rahnella is much more efficient in precipitating U(VI) than Bacillus sp. The precipitation of U(VI) must be mediated ...
Date: April 19, 2007
Creator: Martinez, Robert J.; Beazley, Melanie J.; Webb, Samuel M.; Taillefert, Martial & Sobecky, Patricia A.
Partner: UNT Libraries Government Documents Department

Thermodynamic network model for predicting effects of substrate addition and other perturbations on subsurface microbial communities

Description: 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.
Date: April 19, 2007
Creator: Istok, Jack; Park, Melora; McKinley, James; Liu, Chongxuan; Krumholz, Lee; Spain, Anne et al.
Partner: UNT Libraries Government Documents Department

Stabilization of Plutonium in Subsurface Environments via Microbial Reduction and Biofilm Formation

Description: 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+.
Date: April 19, 2007
Creator: Boukhalfa, Hakim; Icopini, Gary A.; Reilly, Sean D. & Neu, Mary P.
Partner: UNT Libraries Government Documents Department

Applying EMSL Capabilities to Biogeochemistry and Environmental Research

Description: The Environmental Molecular Sciences laboratory (EMSL) is a national scientific user facility operated by the Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy's Office of Biological and Environmental Research. Located in Richland, Washington, EMSL offers researchers a comprehensive array of cutting-edge capabilities unmatched anywhere else in the world and access to the expertise of over 300 resident users--all at one location. EMSL's resources are available on a peer-reviewed proposal basis and are offered at no cost if research results are shared in the open literature. Researchers are encouraged to submit a proposal centered around one of EMSL's four Science Themes, which represent growing areas of research: (1) Geochemistry/Biogeochemistry and Subsurface Science; (2) Atmospheric Aerosol Chemistry; (3) Biological Interactions and Dynamics; and (4) Science of Interfacial Phenomena. To learn more about EMSL, visit www.emsl.pnl.gov.
Date: April 19, 2007
Creator: Felmy, Andy
Partner: UNT Libraries Government Documents Department

[Parade of Flesh x-mas party poster]

Description: Poster advertising the Parade of Flesh x-mas party on December 20, 2007 , at City Tavern, Dallas, Texas, with music performances by Antelope, Attractive & Popular, Balthazar, and El Paso Hot Button. Poster features an illustration of a pink abstract amorphous form with speech bubbles containing the event information in purple text.
Date: 2007
Creator: Hill, Nevada
Location Info:
Partner: UNT Music Library

[Unwed Sailor, This Will Destroy You, Mom poster]

Description: Poster advertising a concert by Unwed Sailor, This Will Destroy You, and Mom on December 16th, 2007, at The Cavern, Dallas, Texas. Poster features a blue and green illustration and hand-drawn text.
Date: 2007
Creator: Hill, Nevada
Location Info:
Partner: UNT Music Library

[Primordial Undermind, Oveo, Ethereal Plains Indian poster]

Description: Poster advertising a concert by Primordial Undermind with Oveo and Ethereal Plains Indian on Wednesday March 7, 2007 at J&J's on the Square, 118 W. Oak St., Denton, Texas. Poster features the band name "Primordial Undermind" in white text over a fuzzy color photograph, a small image of the band's album in the bottom left corner, and other event details handwritten in purple marker.
Date: 2007
Creator: Kapinos, Will
Location Info:
Partner: UNT Music Library

[Lebanon, L'il Tedly, Jetscreamer poster]

Description: Poster advertising a concert by Lebanon, L'il Tedly, and Jetscreamer on March 19, 2007, at J&J's Pizza, 118 W. Oak, Denton, Texas. Poster features an image of black silhouetted hands centrally converging on a white background with event details overlaid in dark pink text.
Date: 2007
Location Info:
Partner: UNT Music Library