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Phytochemial Society of North America 50th Anniversary Meeting

Description: The Phytochemical Society of North America will have its 50th anniversary meeting from December 10 through 15th, 2011, on the big island of Hawaii. The society has a long tradition in the study of plant biochemistry, chemistry, natural products (whether for commodity chemicals, food and fiber sources, renewable energy, pharmaceuticals, nutraceuticals and other bioactive substances). The meeting, being a very special celebration, is anticipated to attract a very broad range of researchers drawn from worldwide locations. This is also reflected in the international composition of our organizing and scientific program committees. We are now finalizing speakers for the PSNA 50 conference which has a variety of scientific themes, including biofuels/bioengineering, transcriptome profiling, metabolism and metabolomics, and new characterization technologies/methodologies. A most important part of our PSNA 50 conference is to provide opportunities for graduate students and postdoctoral fellows to present their research findings and exchange ideas with scientific colleagues. In this regard, the bulk of the funding in support of this conference is anticipated to come from sponsorships (industry, foundations, and so forth) and registrations which are currently underway. It is essential, however, that we strongly encourage the participation of both young graduate students and postdoctoral fellows at our historic meeting. In order to do this, we are requesting financial support from BES to help partially defray travel and registration costs to support 10 graduate students and 10 postdoctoral fellows in BES relevant areas of research. PSNA has a long history of supporting young scientists, including yearly graduate student and PDF competitions for best paper/poster awards. Support from BES would thus build on our previous successes, and enable a much broader and larger group of students/postdoctorals than at previous meetings.
Date: May 1, 2012
Creator: Lewis, Norman G.
Partner: UNT Libraries Government Documents Department

INFLUENCE OF NATURAL AND SYNTHETIC ORGANIC LIGANDS ON THE STABILITY AND MOBILITY OF REDUCED TC(IV)

Description: The primary objectives were (1) to quantify the interactions of organic ligands with Tc(IV) through the generation of thermodynamic (complexation) and kinetic parameters needed to assess and predict the mobility of reduced Tc(IV) at DOE contaminated sites; and (2) to determine the impact of organic ligands on the mobility and fate of reduced Tc(IV) under field geochemical conditions.
Date: December 20, 2012
Creator: Wall, Nathalie A. & Gu, Baohua
Partner: UNT Libraries Government Documents Department

The Energy Budget of Steady State Photosynthesis

Description: Progress is reported in addressing these questions: Why do hcef mutants have increased CEF1? Is increased CEF1 caused by elevated expression or altered regulation of CEF1 components? Which metabolic pools can be regulators of CEF1? Do metabolites influence CEF1 directly or indirectly? Which CEF1 pathways are activated in high CEF1 mutants? Is PQR a proton pump? Is elevated CEF1 activated by state transitions?
Date: November 27, 2012
Creator: Kramer, Dr. David M.
Partner: UNT Libraries Government Documents Department

Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings

Description: This document serves as the Topical Report documenting work completed by Washington State University (WSU) under U.S. Department of Energy Grant, Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings. This project was conducted in collaboration with Oak Ridge National Laboratory (ORNL), and includes the participation of several industry partners including Weyerhaeuser, APA - The Engineered Wood Association, CertainTeed Corporation and Fortifiber. This document summarizes work completed by Washington State University August 2002 through June 2006. WSU's primary experimental role is the design and implementation of a field testing protocol that monitored long term changes in the hygrothermal response of wall systems. During the project period WSU constructed a test facility, developed a matrix of test wall designs, constructed and installed test walls in the test facility, installed instrumentation in the test walls and recorded data from the test wall specimens. Each year reports were published documenting the hygrothermal response of the test wall systems. Public presentation of the results was, and will continue to be, made available to the building industry at large by industry partners and the University.
Date: May 31, 2006
Creator: Tichy, Robert & Murray, Chuck
Partner: UNT Libraries Government Documents Department

Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings

Description: This document serves as the Topical Report documenting the first year of work completed by Washington State University (WSU) under US Department of Energy Grant, Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings. This project is being conducted in collaboration with Oak Ridge National Laboratory (ORNL), and includes the participation of several industry partners including Weyerhaeuser Company, APA - The Engineered Wood Association, CertainTeed Corporation and Fortifiber. This document summarizes work completed by Washington State University August, 2002 through October, 2003. WSU's primary experimental role is the design and implementation of a field testing protocol that will monitor long term changes in the hygrothermal response of wall systems. In the first year WSU constructed a test facility, developed a matrix of test wall designs, constructed and installed test walls in the test facility, and installed instrumentation in the test walls. By the end of the contract period described in this document, WSU was recording data from the test wall specimens. The experiment described in this report will continue through December, 2005. Each year a number of reports will be published documenting the hygrothermal response of the test wall systems. Public presentation of the results will be made available to the building industry by industry partners and the University cooperators.
Date: October 1, 2003
Creator: Tichy, Robert & Murray, Chuck
Partner: UNT Libraries Government Documents Department

MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS

Description: The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.
Date: November 14, 2013
Creator: Beyenal, Haluk; McLEan, Jeff; Majors, Paul & Fredrickson, Jim
Partner: UNT Libraries Government Documents Department

Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms

Description: With increased application of MOX fuels and longer burnup times for conventional fuels, higher concentrations of the transplutonium actinides Am and Cm (and even heavier species like Bk and Cf) will be produced. The half-lives of the Am isotopes are significantly longer than those of the most important long-lived, high specific activity lanthanides or the most common Cm, Bk and Cf isotopes, thus the greatest concern as regards long-term radiotoxicity. With the removal and transmutation of Am isotopes, radiation levels of high level wastes are reduced to near uranium mineral levels within less than 1000 years as opposed to the time-fram if they remain in the wastes.
Date: September 23, 2009
Creator: Nash, Kenneth L.; Clark, Sue B. & Lumetta, Gregg
Partner: UNT Libraries Government Documents Department

Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms

Description: Implementation of a closed loop nuclear fuel cycle requires the utilization of Pu-containing MOX fuels with the important side effect of increased production of the transplutonium actinides, most importantly isotopes of Am and Cm. Because the presence of these isotopes significantly impacts the long-term radiotoxicity of high level waste, it is important that effective methods for their isolation and/or transmutation be developed. Furthermore, since transmutation is most efficiently done in the absence of lanthanide fission products (high yield species with large thermal neutron absorption cross sections) it is important to have efficient procedures for the mutual separation of Am and Cm from the lanthanides. The chemistries of these elements are nearly identical, differing only in the slightly stronger strength of interaction of trivalent actinides with ligand donor atoms softer than O (N, Cl-, S). Research being conducted around the world has led to the development of new reagents and processes with considerable potential for this task. However, pilot scale testing of these reagents and processes has demonstrated the susceptibility of the new classes of reagents to radiolytic and hydrolytic degradation. In this project, separations of trivalent actinides from fission product lanthanides have been investigated in studies of 1) the extraction and chemical stability properties of a class of soft-donor extractants that are adapted from water-soluble analogs, 2) the application of water soluble soft-donor complexing agents in tandem with conventional extractant molecules emphasizing fundamental studies of the TALSPEAK Process. This research was conducted principally in radiochemistry laboratories at Washington State University. Collaborators at the Radiological Processing Laboratory (RPL) at the Pacific Northwest National Laboratory (PNNL) have contributed their unique facilities and capabilities, and have supported student internships at PNNL to broaden their academic experience. New information has been developed to qualify the extraction potential of a class of pyridine-functionalized tetraaza complexants ...
Date: September 22, 2009
Creator: Nash, Kenneth L.
Partner: UNT Libraries Government Documents Department

Final report on Grant DE-FG03-01ER63234

Description: Current data suggests that radiation-induced bystander effects (RIBE) are associated with release of active polypeptide factors into the extra-cellular medium. Proteolytic processing of membrane-anchored cytokines (shedding) is a generic cellular response to environmental stress; hence, it is likely that RIBE are part of a general mechanism by which cells alert their neighbors to potential harm by exchange of autocrine and paracrine factors. In radiation biology, we lack a general understanding of the relative importance of shed factors in the overall response of tissues to energy absorbed from a radiation field. This project helped fill that knowledge gap by investigating (1) the production of soluble factors by cells traversed by ionizing particles, (2) transport of soluble factors through the extra-cellular medium, and (3) signaling processes initiate by capture of soluble factors on cell-surface receptors.
Date: November 16, 2006
Creator: Miller, John H.
Partner: UNT Libraries Government Documents Department

Final Report on Grant DE-FG03-02ER63470

Description: The goal of this project is to provide critical information to characterize the qualitative and quantitative similarities and difference in repair characteristics between clustered damage sites formed by ionizing radiation and singly damaged sites produced by endogenous processes. The premise is that base pairing and base stacking interactions are qualitatively and quantitatively different for singly and multiply damaged DNA sites. State-of-the-art computational chemistry model were used to characterize the structure, energetics, and spectroscopy of singly and multiply damaged (clustered) DNA sites.
Date: November 20, 2006
Creator: Miller, John H.
Partner: UNT Libraries Government Documents Department

Colloid-Facilitated Transport of Radionuclides through the Vadose Zone

Description: The main purpose of this project was to advance the basic scientific understanding of colloid and colloid-facilitated Cs transport of radionuclides in the vadose zone. We focused our research on the hydrological and geochemical conditions beneath the leaking waste tanks at the USDOE Hanford reservation. Specific objectives were (1) to determine the lability and thermodynamic stability of colloidal materials, which form after reacting Hanford sediments with simulated Hanford Tank Waste, (2) to characterize the interactions between colloidal particles and contaminants, i.e., Cs and Eu, (3) to determine the potential of Hanford sediments for \textit{in situ} mobilization of colloids, (4) to evaluate colloid-facilitated radionuclide transport through sediments under unsaturated flow, (5) to implement colloid-facilitated contaminant transport mechanisms into a transport model, and (6) to improve conceptual characterization of colloid-contaminant-soil interactions and colloid-facili\-tated transport for clean-up procedures and long-term risk assessment. We have previously shown that upon contact with simulated waste tank solutions, Hanford sediments change their mineralogical composition. Certain minerals, i.e., quartz, smectite, and kaolinite, are partially dissolved, and new mineral phases, i.e., the feldspathoids cancrinite and sodalite, are formed. We have characterized these mineral transformations and clarified the mineral transformation pathways. The new minerals were mainly in the colloidal size fraction (diameter less than 2 mum), had a negative surface charge, and were microporous, meaning they contained small pores. When Cs was present during the formation of the minerals, contaminants, like Cs, could be trapped inside the mineral structure. Transport experiments under water saturated and unsaturated conditions showed that the colloids were mobile in Hanford sediments. As the water saturation of the sediments decreased, the amount of colloids transported also decreased. The colloids had the ability to enhance the migration of the radionuclide Cs; however, Cs initially sorbed to colloids was desorbed during transport through uncontaminated Hanford sediments. The finding ...
Date: November 21, 2006
Creator: Flury, Markus; Harsh, James B.; McCarthy, John F.; Lichtner, Peter C. & Zachara, John M.
Partner: UNT Libraries Government Documents Department

Membrane-Organized Chemical Photoredox Systems

Description: This project has three interrelated goals relevant to solar water photolysis, which are to develop: (1) vesicle-organized assemblies for H2 photoproduction that utilize pyrylium and structurally related compounds as combined photosensitizers and cyclic electroneutral transmembrane electron carriers; (2) transmembrane redox systems whose reaction rates can be modulated by light; and (3) homogeneous catalysts for water oxidation. In area (1), initial efforts to photogenerate H2 from vectorially-organized vesicles containing occluded colloidal Pt and commonly available pyrylium ions as transmembrane redox mediators were unsuccessful. New pyrylium compounds with significantly lower reduction potentials have been synthesized to address this problem and their apparent redox potentials in functioning systems have been now evaluated by using a series of occluded viologens. These studies provide an estimate of thermodynamic constraints imposed by these assemblies on hydrogen photoproduction. In area (2), spirooxazine-quinone dyads have been synthesized and their capacity to function as redox mediators across bilayer membranes has been evaluated through continuous photolysis and transient spectrophotometric measurements. These studies provide information on how quinone pools transfer charge in biomimetic systems designed to store solar energy as transmembrane electrochemical gradients. Photoisomerization of the spiro moiety to the ring-open mero form caused net quantum yields to decrease significantly, providing a basis for photoregulation of transmembrane redox; unexpectedly, both electrogenic and electroneutral pathways were observed, which were dependent upon the isomeric state of the chromophore (mero vs. spiro) and quinone substituent groups. Research on water oxidation (area 3) has been directed at understanding mechanisms of catalysis by cis,cis-[(bpy)2Ru(OH2)]2O4+ and related polyimine complexes. Using a variety of physical techniques, we have: (i) identified the redox state of the complex ion that is catalytically active; (ii) shown using 18O isotopic labeling that there are two reaction pathways, both of which involve participation of solvent H2 O; and (iii) detected by EPR and ...
Date: May 15, 2007
Creator: Hurst, James K.
Partner: UNT Libraries Government Documents Department

Early Transition Metal Oxides as Catalysts: Crossing Scales from Clusters to Single Crystals to Functioning Materials

Description: The overall goal of this program is to investigate the electronic structure and chemical bonding of early transition metal oxide clusters and use them as well-defined molecular models to obtain insight into properties and mechanisms of oxide catalysts, as well as to provide accurate spectroscopic and molecular information to verify theoretical methods used to predict materials properties. A laser vaporization cluster source is used to produce metal oxide clusters with different sizes, structures, and compositions. Well-defined inorganic polyoxometalate clusters in solution are transported in the gas phase using electrospray. Two state-of-the-art photoelectron spectroscopy apparatuses are used to interrogate the oxide clusters and polyoxometalate anions in the gas phase to obtain spectroscopic and electronic structure information. The experimental effort is assisted by theoretical calculations to understanding the structures, chemical bonding, and catalytical properties of the transition metal oxide clusters. The research approach combines novel and flexible experimental techniques and advanced theoretical/computational methodologies and seeks molecular-level information to aiding the design of new catalysts, as well as mechanistic understanding. We have focused on the investigation of tungsten oxide clusters containing three W atoms: W{sub 3}O{sub x}{sup -} (x = 7-11). A number of interesting findings have been made. We observed that the oxygen-poor W{sub 3}O8 cluster contains a localized W{sup 4+} center, which can be used as a molecular model for O-deficient defect sites. A chemisorption energy was obtained through density functional calculations for W{sub 3}O8 + O{sub 2} {yields} W{sub 3}O{sub 10} as -78 kcal/mol. We further found that the neutral stoichiometric W{sub 2}O{sub 6} and W{sub 3}O{sub 9} clusters do not react with O{sub 2} and they only form physi-sorbed complexes, W{sub 2}O{sub 6}(O{sub 2}) and W{sub 3}O{sub 9}(O{sub 2}). However, the negatively charged W{sub 2}O{sub 6}{sup -} and W{sub 3}O{sub 9}{sup -} clusters are found to form chemisorbed complexes ...
Date: July 7, 2009
Creator: Wang, Lai-Sheng
Partner: UNT Libraries Government Documents Department

Mechanisms of CCl4 Retention and Slow Release in Model Porous Solids and Sediments

Description: This work is part of a larger collaborative project of the same title led by Robert Riley at PNNL. Our task goal is to use a state of the art microbalance and well-defined mesoporous silica particles to characterize the effects of pore size distribution on carbon tetrachloride release rate and sequestration.
Date: December 1, 2004
Creator: Peyton, Brent M.
Partner: UNT Libraries Government Documents Department

Long-Term Colloid Mobilization And Colloid-Facilitated Transport Of Radionuclides In A Semi-Arid Vadose Zone

Description: The main purpose of this project was to improve the fundamental mechanistic understanding and quantification of long-term colloid mobilization and colloid-facilitated transport of radionuclides in the vadose zone, with special emphasis on the semi-arid Hanford site. While we focused some of the experiments on hydrogeological and geochemical conditions of the Hanford site, many of our results apply to colloid and colloid-facilitated transport in general. Specific objectives were (1) to determine the mechanisms of colloid mobilization and colloid-facilitated radionuclide transport in undisturbed Hanford sediments under unsaturated flow, (2) to quantify in situ colloid mobilization and colloid-facilitated radionuclide transport from Hanford sediments under field conditions, and (3) to develop a field-scale conceptual and numerical model for colloid mobilization and transport at the Hanford vadose zone, and use that model to predict long-term colloid and colloid- facilitated radionuclide transport. To achieve these goals and objectives, we have used a combination of experimental, theoretical, and numerical methods at different spatial scales, ranging from microscopic investigations of single particle attachment and detachment to larger-scale field experiments using outdoor lysimeters at the Hanford site. Microscopic and single particle investigations provided fundamental insight into mechanisms of colloid interactions with the air-water interface. We could show that a moving air water interface (such as a moving water front during infiltration and drainage) is very effective in removing and mobilizing particles from a stationary surface. Field experiment using a vadose zone lysimeter facility at the Hanford site showed that surface-applied Eu colloids can be translocated rapidly under natural precipitation as well as artificial irrigation. Small amounts of applied colloids were translocated from the surface to a depth of two meters within two months and only 20 mm of cumulative infiltration. Large water infiltration events, mimicking snow melt, enhanced movement of Eu colloids. Nonetheless the majority of Eu colloids remained ...
Date: November 5, 2012
Creator: Flury, Markus; Harsh, James B; Zhang, Fred; Gee, Glendon W; Mattson, Earl D & Lichtner, Peter C
Partner: UNT Libraries Government Documents Department

Characterization of Actinides in Simulated Alkaline Tank Waste Sludges and Leachates

Description: Removal of waste-limiting components of sludge (Al, Cr, S, P) in underground tanks at Hanford by treatment with concentrated alkali has proven less efficacious for Al and Cr removal than had been hoped. More aggressive treatments of sludges, for example, contact with oxidants targeting Cr(III), have been tested in a limited number of samples and found to improve leaching efficiency for Cr. Oxidative alkaline leaching can be expected to have at best a secondary influence on the mobilization of Al. Our earlier explorations of Al leaching from sludge simulants indicated acidic and complexometric leaching can improve Al dissolution. Unfortunately, treatments of sludge samples with oxidative alkaline, acidic or complexing leachates produce conditions under which normally insoluble actinide ions (e.g., Am3+, Pu4+, Np4+) can be mobilized to the solution phase. Few experimental or meaningful theoretical studies of actinide chemistry in strongly alkaline, strongly oxidizing solutions have been completed. Unfortunately, extrapolation of the more abundant acid phase thermodynamic data to these radically different conditions provides limited reliable guidance for predicting actinide speciation in highly salted alkaline solutions. In this project, we are investigating the fundamental chemistry of actinides and important sludge components in sludge simulants and supernatants under representative oxidative leaching conditions. We are examining the potential impact of acidic or complexometric leaching with concurrent secondary separations on Al removal from sludges. Finally, a portion of our research is directed at the control of polyvalent anions (SO4=, CrO4=, PO43-) in waste streams destined for vitrification. Our primary objective is to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop. We expect to identify those components of sludges that are likely to be problematic in the application of oxidative, acidic, and complexometric leaching protocols.
Date: June 1, 2005
Creator: Nash, Kenneth L.
Partner: UNT Libraries Government Documents Department

Characterization of Actinides in Simulated Alkaline Tank Waste Sludges and Leachates

Description: Removal of waste-limiting components of sludge (Al, Cr, S, P) in underground tanks at Hanford by treatment with concentrated alkali has proven less efficacious for Al and Cr removal than had been hoped. More aggressive treatments of sludges, for example, contact with oxidants targeting Cr(III), have been tested in a limited number of samples and found to improve leaching efficiency for Cr. Oxidative alkaline leaching can be expected to have at best a secondary influence on the mobilization of Al. Our earlier explorations of Al leaching from sludge simulants indicated acidic and complexometric leaching can improve Al dissolution. Unfortunately, treatments of sludge samples with oxidative alkaline, acidic or complexing leachates produce conditions under which normally insoluble actinide ions (e.g., Am3+, Pu4+, Np4+) can be mobilized to the solution phase. Few experimental or meaningful theoretical studies of actinide chemistry in strongly alkaline, strongly oxidizing solutions have been completed. Unfortunately, extrapolation of the more abundant acid phase thermodynamic data to these radically different conditions provides limited reliable guidance for predicting actinide speciation in highly salted alkaline solutions. In this project, we are investigating the fundamental chemistry of actinides and important sludge components in sludge simulants and supernatants under representative oxidative leaching conditions. We are examining the potential impact of acidic or complexometric leaching with concurrent secondary separations on Al removal from sludges. Finally, a portion of our research is directed at the control of polyvalent anions (SO4=, CrO4=, PO43-) in waste streams destined for vitrification. Our primary objective is to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop. We expect to identify those components of sludges that are likely to be problematic in the application of oxidative, acidic, and complexometric leaching protocols.
Date: June 1, 2005
Creator: Nash, Kenneth L.
Partner: UNT Libraries Government Documents Department

Characterization of Actinides in Simulated Alkaline Tank Waste Sludges and Leachates

Description: Removal of waste-limiting components of sludge (Al, Cr, S, P) in underground tanks at Hanford by treatment with concentrated alkali has proven less efficacious for Al and Cr removal than had been hoped. More aggressive treatments of sludges, for example, contact with oxidants targeting Cr(III), have been tested in a limited number of samples and found to improve leaching efficiency for Cr. Oxidative alkaline leaching can be expected to have at best a secondary influence on the mobilization of Al. Our earlier explorations of Al leaching from sludge simulants indicated acidic and complexometric leaching can improve Al dissolution. Unfortunately, treatments of sludge samples with oxidative alkaline, acidic or complexing leachates produce conditions under which normally insoluble actinide ions (e.g., Am3+, Pu4+, Np4+) can be mobilized to the solution phase. Few experimental or meaningful theoretical studies of actinide chemistry in strongly alkaline, strongly oxidizing solutions have been completed. Unfortunately, extrapolation of the more abundant acid phase thermodynamic data to these radically different conditions provides limited reliable guidance for predicting actinide speciation in highly salted alkaline solutions. In this project, we are investigating the fundamental chemistry of actinides and important sludge components in sludge simulants and supernatants under representative oxidative leaching conditions. We are examining the potential impact of acidic or complexometric leaching with concurrent secondary separations on Al removal from sludges. Finally, a portion of our research is directed at the control of polyvalent anions (SO4=, CrO4=, PO43-) in waste streams destined for vitrification. Our primary objective is to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop. We expect to identify those components of sludges that are likely to be problematic in the application of oxidative, acidic, and complexometric leaching protocols.
Date: June 1, 2005
Creator: Nash, Kenneth L.
Partner: UNT Libraries Government Documents Department

CHARACTERIZATION OF ACTINIDES IN SIMULATED ALKALINE TANK WASTE SLUDGES AND LEACHATES

Description: In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinides under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.
Date: November 20, 2008
Creator: Nash, Kenneth L.
Partner: UNT Libraries Government Documents Department

Colloid-Facilitated Transport of Radionuclides Through the Vadose Zone

Description: In the previous reporting period, we have clarified the qualitative mineral transformation pathways when Hanford sediments are reacted with caustic Hanford tank waste. The major finding was that cancrinite, sodalite, zeolite A and allophane form when Hanford tank waste leaks into subsurface sediments. Cancrinite and sodalite are the most stable phases. The morphology and crystallinity of the minerals formed vary with alkalinity, salinity, and the Si/Al ratio. Temperature affects the reaction rates, but not the reaction pathways. In this project period, we have further refined the reaction pathways by quantification of XRD patterns and determination of weight fractions of individual minerals. This allowed us to generalize the results as function of solution chemistry.
Date: June 1, 2005
Creator: Flury, Markus
Partner: UNT Libraries Government Documents Department

Colloid-Facilitated Transport of Radionuclides through the Vadose Zone

Description: In the previous reporting period, we have clarified the qualitative mineral transformation pathways when Hanford sediments are reacted with caustic Hanford tank waste. The major finding was that cancrinite, sodalite, zeolite A and allophane form when Hanford tank waste leaks into subsurface sediments. Cancrinite and sodalite are the most stable phases. The morphology and crystallinity of the minerals formed vary with alkalinity, salinity, and the Si/Al ratio. Temperature affects the reaction rates, but not the reaction pathways. In this project period, we have further refined the reaction pathways by quantification of XRD patterns and determination of weight fractions of individual minerals. This allowed us to generalize the results as function of solution chemistry.
Date: June 1, 2005
Creator: Flury, Markus
Partner: UNT Libraries Government Documents Department

The Energy Budget of Steady-State Photosynthesis

Description: Our work developed a unique set of in vivo spectroscopic tools that have allowed us to probe the importance of 1) The effects of storage of proton motive force (pmf ) in the form of both electric field (Δψ) and pH difference (ΔpH); 2) alteration in the stoichiometry of proton pumping to electron transfer at key steps; 3) the influence of changes in the conductivity for proton efflux from the thylakoid of the ATP synthase; 4) the mechanisms of steps of the electron transfer process that pump protons; and 5) the mechanisms by which reactive O{sub 2} is generated as a side reaction to photosynthesis, and how these processes are minimized.
Date: June 30, 2007
Creator: Kramer, David
Partner: UNT Libraries Government Documents Department