Language

Carbon-14 geochemistry at the Savannah River Site (open access)

Carbon-14 geochemistry at the Savannah River Site

Carbon-14 is among the key radionuclides driving risk at the E-Area Low-Level Waste Disposal Facility on the Savannah River Site (SRS). Much of this calculated risk is believed to be the result of having to make conservative assumptions in risk calculations because of the lack of site-specific data. The original geochemical data package (Kaplan 2006) recommended that performance assessments and composite analyses for the SRS assume that {sup 14}C did not sorbed to sediments or cementitious materials, i.e., that C-14 K{sub d} value (solid:liquid concentration ratio) be set to 0 mL/g (Kaplan 2006). This recommendation was based primarily on the fact that no site-specific experimental work was available and the assumption that the interaction of anionic {sup 14}C as CO{sub 2}{sup 2-}) with similarly charged sediments or cementitious materials would be minimal. When used in reactive transport equations, the 0 mL/g Kd value results in {sup 14}C not interacting with the solid phase and moving quickly through the porous media at the same rate as water. The objective of this study was to quantify and understand how aqueous {sup 14}C, as dissolved carbonate, sorbs to and desorbs from SRS sediments and cementitious materials. Laboratory studies measuring the sorption of {sup …
Date: May 10, 2013
Creator: Roberts, Kimberly A. & Kaplan, Daniel I.
Object Type: Report
System: The UNT Digital Library
Collisionality Scaling of Main-ion Toroidal and Poloidal Rotation in Low Torque DIII-D Plasmas (open access)

Collisionality Scaling of Main-ion Toroidal and Poloidal Rotation in Low Torque DIII-D Plasmas

In tokamak plasmas with low levels of toroidal rotation, the radial electric fi eld Er is a combination of pressure gradient and toroidal and poloidal rotation components, all having similar magnitudes. In order to assess the validity of neoclassical poloidal rotation theory for determining the poloidal rotation contribution to Er , Dα emission from neutral beam heated tokamak discharges in DIII-D [J.L. Luxon, Nucl. Fusion 42 , 614 (2002)] has been evaluated in a sequence of low torque (electron cyclotron resonance heating and balanced diagnostic neutral beam pulse) discharges to determine the local deuterium toroidal rotation velocity. By invoking the radial force balance relation the deuterium poloidal rotation can be inferred. It is found that the deuterium poloidal low exceeds the neoclassical value in plasmas with collisionality #23;#3; νi < 0: 1, being more ion diamagnetic, and with a stronger dependence on collisionality than neoclassical theory predicts. At low toroidal rotation, the poloidal rotation contribution to the radial electric fi eld and its shear is signi cant. The eff ect of anomalous levels of poloidal rotation on the radial electric fi eld and cross fi eld heat transport is investigated for ITER parameters.
Date: May 10, 2013
Creator: Grierson, B. A.; Burrell, K. H.; Solomon, W. M.; Budny, R. V. & Candy, J.
Object Type: Report
System: The UNT Digital Library
Design of the Energy Partitioning Energy Coupling (EPEC) NIF Experiment (open access)

Design of the Energy Partitioning Energy Coupling (EPEC) NIF Experiment

None
Date: May 10, 2013
Creator: Kane, J. O.; Brooksby, C. A.; Brown, C. G.; Compton, S. M.; Dunlop, W. H.; Fournier, K. B. et al.
Object Type: Report
System: The UNT Digital Library
An Efficient Inclusion Test for A Massive Point Distribution (open access)

An Efficient Inclusion Test for A Massive Point Distribution

None
Date: May 10, 2013
Creator: Yao, J
Object Type: Report
System: The UNT Digital Library
Multi-Fluid Geothermal Energy Production and Storage in Stratigraphic Reservoirs (open access)

Multi-Fluid Geothermal Energy Production and Storage in Stratigraphic Reservoirs

None
Date: May 10, 2013
Creator: Buscheck, T A; Chen, M; Hao, Y; Bielicki, J M; Randolph, J B; Sun, Y et al.
Object Type: Article
System: The UNT Digital Library
A NMR-Based Carbon-Type Analysis of Diesel Fuel Blends From Various Sources (open access)

A NMR-Based Carbon-Type Analysis of Diesel Fuel Blends From Various Sources

In collaboration with participants of the Coordinating Research Council (CRC) Advanced Vehicle/Fuels/Lubricants (AVFL) Committee, and project AVFL-19, the characteristics of fuels from advanced and renewable sources were compared to commercial diesel fuels. The main objective of this study was to highlight similarities and differences among the fuel types, i.e. ULSD, renewables, and alternative fuels, and among fuels within the different fuel types. This report summarizes the carbon-type analysis from 1H and 13C{1H} nuclear magnetic resonance spectroscopy (NMR) of 14 diesel fuel samples. The diesel fuel samples come from diverse sources and include four commercial ultra-low sulfur diesel fuels (ULSD), one gas-to-liquid diesel fuel (GTL), six renewable diesel fuels (RD), two shale oil-derived diesel fuels, and one oil sands-derived diesel fuel. Overall, the fuels examined fall into two groups. The two shale oil-derived samples and the oil-sand-derived sample closely resemble the four commercial ultra-low sulfur diesels, with SO1 and SO2 most closely matched with ULSD1, ULSD2, and ULSD4, and OS1 most closely matched with ULSD3. As might be expected, the renewable diesel fuels, with the exception of RD3, do not resemble the ULSD fuels because of their very low aromatic content, but more closely resemble the gas-to-liquid sample (GTL) in this …
Date: May 10, 2013
Creator: Bays, J. Timothy & King, David L.
Object Type: Report
System: The UNT Digital Library
An online application to measue the dispersion function in AGS (open access)

An online application to measue the dispersion function in AGS

N/A
Date: May 10, 2013
Creator: N., Tsoupas; Huang, H.; Meot, F.; Morris, J. & Nemesure, S.
Object Type: Report
System: The UNT Digital Library
Scharz Preconditioners for Krylov Methods: Theory and Practice (open access)

Scharz Preconditioners for Krylov Methods: Theory and Practice

Several numerical methods were produced and analyzed. The main thrust of the work relates to inexact Krylov subspace methods for the solution of linear systems of equations arising from the discretization of partial di#11;erential equa- tions. These are iterative methods, i.e., where an approximation is obtained and at each step. Usually, a matrix-vector product is needed at each iteration. In the inexact methods, this product (or the application of a preconditioner) can be done inexactly. Schwarz methods, based on domain decompositions, are excellent preconditioners for thise systems. We contributed towards their under- standing from an algebraic point of view, developed new ones, and studied their performance in the inexact setting. We also worked on combinatorial problems to help de#12;ne the algebraic partition of the domains, with the needed overlap, as well as PDE-constraint optimization using the above-mentioned inexact Krylov subspace methods.
Date: May 10, 2013
Creator: Szyld, Daniel B.
Object Type: Report
System: The UNT Digital Library
Biofuels from Bacteria, Electricity, and CO2 (open access)

Biofuels from Bacteria, Electricity, and CO2

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Electrofuels program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses combining ammonia and bacteria to produce liquid fuel as part of the "Biofuels from CO2 Using Ammonia or Iron-Oxidizing Bacteria in Reverse Microbial Fuel Cells" project.
Date: May 10, 2012
Creator: Columbia University
Object Type: Text
System: The UNT Digital Library
Biofuels from E. coli (open access)

Biofuels from E. coli

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Electrofuels program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses the modification of E. coli to consume carbon dioxide and produce liquid fuel as part of the "Engineering E. coli as an Electrofuels Chassis for Isooctane Production" project.
Date: May 10, 2012
Creator: Ginkgo Bioworks
Object Type: Text
System: The UNT Digital Library
Biofuels from Solar Energy and Bacteria (open access)

Biofuels from Solar Energy and Bacteria

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Electrofuels program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses the conversion of carbon dioxide into liquid fuels as part of the "Electrofuels Via Direct Electron Transfer from Electrodes to Microbes" project.
Date: May 10, 2012
Creator: University of Massachusetts Amherst
Object Type: Text
System: The UNT Digital Library
BLENDING ANALYSIS FOR RADIOACTIVE SALT WASTE PROCESSING FACILITY (open access)

BLENDING ANALYSIS FOR RADIOACTIVE SALT WASTE PROCESSING FACILITY

Savannah River National Laboratory (SRNL) evaluated methods to mix and blend the contents of the blend tanks to ensure the contents are properly blended before they are transferred from the blend tank such as Tank 21 and Tank 24 to the Salt Waste Processing Facility (SWPF) feed tank. The tank contents consist of three forms: dissolved salt solution, other waste salt solutions, and sludge containing settled solids. This paper focuses on developing the computational model and estimating the operation time of submersible slurry pump when the tank contents are adequately blended prior to their transfer to the SWPF facility. A three-dimensional computational fluid dynamics approach was taken by using the full scale configuration of SRS Type-IV tank, Tank 21H. Major solid obstructions such as the tank wall boundary, the transfer pump column, and three slurry pump housings including one active and two inactive pumps were included in the mixing performance model. Basic flow pattern results predicted by the computational model were benchmarked against the SRNL test results and literature data. Tank 21 is a waste tank that is used to prepare batches of salt feed for SWPF. The salt feed must be a homogeneous solution satisfying the acceptance criterion of …
Date: May 10, 2012
Creator: Lee, S.
Object Type: Article
System: The UNT Digital Library
Electric Vehicle Batteries (open access)

Electric Vehicle Batteries

Advanced Research Projects Agency-Energy project sheet summarizing general information about the 10 projects that are a part of the Batteries for Electrical Energy Storage in Transportation (BEEST) program including project goals, innovation needs, and potential impacts.
Date: May 10, 2012
Creator: United States. Advanced Research Projects Agency-Energy.
Object Type: Text
System: The UNT Digital Library
Energetics and approximate quasiparticle electronic structure of low-index surfaces of SnO2 (open access)

Energetics and approximate quasiparticle electronic structure of low-index surfaces of SnO2

None
Date: May 10, 2012
Creator: Kuefner, S; Schleife, A; Hoeffling, B & Bechstedt, F
Object Type: Article
System: The UNT Digital Library
Engineering Bacteria for Efficient Fuel Production (open access)

Engineering Bacteria for Efficient Fuel Production

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Electrofuels program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses engineering a microorganism to create a liquid fuel from hydrogen and carbon dioxide as part of the "Novel Biological Conversion of Hydrogen and Carbon Dioxide Directly into Free Fatty Acids" project.
Date: May 10, 2012
Creator: OPX Biotechnologies
Object Type: Text
System: The UNT Digital Library
Extension of the Supercritical Carbon Dioxide Brayton Cycle to Low Reactor Power Operation: Investigations Using the Coupled Anl Plant Dynamics Code-sas4a/Sassys-1 Liquid Metal Reactor Code System. (open access)

Extension of the Supercritical Carbon Dioxide Brayton Cycle to Low Reactor Power Operation: Investigations Using the Coupled Anl Plant Dynamics Code-sas4a/Sassys-1 Liquid Metal Reactor Code System.

Significant progress has been made on the development of a control strategy for the supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle enabling removal of power from an autonomous load following Sodium-Cooled Fast Reactor (SFR) down to decay heat levels such that the S-CO{sub 2} cycle can be used to cool the reactor until decay heat can be removed by the normal shutdown heat removal system or a passive decay heat removal system such as Direct Reactor Auxiliary Cooling System (DRACS) loops with DRACS in-vessel heat exchangers. This capability of the new control strategy eliminates the need for use of a separate shutdown heat removal system which might also use supercritical CO{sub 2}. It has been found that this capability can be achieved by introducing a new control mechanism involving shaft speed control for the common shaft joining the turbine and two compressors following reduction of the load demand from the electrical grid to zero. Following disconnection of the generator from the electrical grid, heat is removed from the intermediate sodium circuit through the sodium-to-CO{sub 2} heat exchanger, the turbine solely drives the two compressors, and heat is rejected from the cycle through the CO{sub 2}-to-water cooler. To investigate the effectiveness …
Date: May 10, 2012
Creator: Moisseytsev, A. & Sienicki, J. J. (Nuclear Engineering Division)
Object Type: Report
System: The UNT Digital Library
Fuel from Bacteria (open access)

Fuel from Bacteria

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program to genetically modify bacteria to generate Butanol from carbon dioxide (project title "Bioconversion of Carbon Dioxide to Biofuels by Facultatively Autotrophic Hydrogen Bacteria") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 10, 2012
Creator: Ohio State University
Object Type: Text
System: The UNT Digital Library
Fuel from Bacteria, CO2, Water, and Solar Energy (open access)

Fuel from Bacteria, CO2, Water, and Solar Energy

Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program to generate liquid fuels from bacteria, carbon dioxide, water, and sunlight (project title "Engineering a Bacterial Reverse Fuel Cell") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 10, 2012
Creator: Harvard Medical School. Wyss Institute
Object Type: Text
System: The UNT Digital Library
Genetically Modified Bacteria for Fuel Production (open access)

Genetically Modified Bacteria for Fuel Production

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Electrofuels program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses a new program to develop a bacteria that uses electricity to convert carbon dioxide into liquid fuels as part of the "Development of Rhodobacter as a Versatile Platform for Fuels Production" project.
Date: May 10, 2012
Creator: Pennsylvania State University
Object Type: Text
System: The UNT Digital Library
Graphical User Interface Software for Gross Defect Detection at the Atucha-I Plant (open access)

Graphical User Interface Software for Gross Defect Detection at the Atucha-I Plant

At the Atucha-I pressurized heavy water reactor in Argentina, fuel assemblies in the spent fuel pools are stored by suspending them in two vertically stacked layers. This introduces the unique problem of verifying the presence of fuel in either layer without physically moving the fuel assemblies. Movement of fuel, especially from the lower layer, would involve a major effort on the part of the operator. Given that the facility uses both natural uranium and slightly enriched uranium at 0.85 w% {sup 235}U, and has been in operation since 1974, a wide range of burnups and cooling times can exist in any given pool. Additionally, while fuel assemblies are grouped together in a uniform fashion, the packing density from group to group can vary within a single pool. A tool called the Spent Fuel Neutron Counter (SFNC) was developed and successfully tested at the site to verify, in an in-situ condition, the presence of fuel up to burnups of 8,000 MWd/t. Since the neutron source term becomes a nonlinear function of burnup beyond this burnup, a new algorithm was developed to predict expected response from the SFNC at measurement locations covering the entire range of burnups, cooling times, and initial enrichments. …
Date: May 10, 2012
Creator: Wong, Alden C.; Sitaraman, Shivakumar; Ham, Young S. & Peixoto, Orpet J. M.
Object Type: Article
System: The UNT Digital Library
High Energy Density Capacitors (open access)

High Energy Density Capacitors

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Batteries for Electrical Energy Storage in Transportation (BEEST) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses a new capacitor design for electric vehicles as part of the "High Energy Density Capacitors" project.
Date: May 10, 2012
Creator: Recapping, Inc.
Object Type: Text
System: The UNT Digital Library
LITERATURE REVIEW ON IMPACT OF GLYCOLATE ON THE 2H EVAPORATOR AND THE EFFLUENT TREATMENT FACILITY (open access)

LITERATURE REVIEW ON IMPACT OF GLYCOLATE ON THE 2H EVAPORATOR AND THE EFFLUENT TREATMENT FACILITY

Glycolic acid (GA) is being studied as an alternate reductant in the Defense Waste Processing Facility (DWPF) feed preparation process. It will either be a total or partial replacement for the formic acid that is currently used. A literature review has been conducted on the impact of glycolate on two post-DWPF downstream systems - the 2H Evaporator system and the Effluent Treatment Facility (ETF). The DWPF recycle stream serves as a portion of the feed to the 2H Evaporator. Glycolate enters the evaporator system from the glycolate in the recycle stream. The overhead (i.e., condensed phase) from the 2H Evaporator serves as a portion of the feed to the ETF. The literature search revealed that virtually no impact is anticipated for the 2H Evaporator. Glycolate may help reduce scale formation in the evaporator due to its high complexing ability. The drawback of the solubilizing ability is the potential impact on the criticality analysis of the 2H Evaporator system. It is recommended that at least a theoretical evaluation to confirm the finding that no self-propagating violent reactions with nitrate/nitrites will occur should be performed. Similarly, identification of sources of ignition relevant to glycolate and/or update of the composite flammability analysis to …
Date: May 10, 2012
Creator: Adu-Wusu, K.
Object Type: Report
System: The UNT Digital Library
Long-Term Hydrologic Monitoring Program Sampling and Analysis Results for 2011 at Rulison, Colorado (open access)

Long-Term Hydrologic Monitoring Program Sampling and Analysis Results for 2011 at Rulison, Colorado

The U.S. Department of Energy (DOE) Office of Legacy Management conducted annual sampling at the Rulison, Colorado, Site for the Long-Term Hydrologic Monitoring Program (LTHMP) on May 18, 2011. The samples were shipped to the U.S. Environmental Protection Agency (EPA) Radiation and Indoor Environments National Laboratory in Las Vegas, Nevada, for analysis. All requested analyses were successfully completed, with the exception of the determination of tritium concentration by the enrichment method. The laboratory no longer provides that service. Samples were analyzed for gamma-emitting radionuclides by high-resolution gamma spectrometry and for tritium using the conventional method. Starting in 2012, DOE will retain a different laboratory that provides the enriched tritium analysis service.
Date: May 10, 2012
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Longitudinal Emittance Growth Due to Nonlinear Space Charge Effect (open access)

Longitudinal Emittance Growth Due to Nonlinear Space Charge Effect

None
Date: May 10, 2012
Creator: Lau, Y. Y.; Yu, S. S.; Barnard, J. J. & Seidl, P. A.
Object Type: Article
System: The UNT Digital Library