Natural Tracers and Multi-Scale Assessment of Caprock Sealing Behavior: A Case Study of the Kirtland Formation, San Juan Basin (open access)

Natural Tracers and Multi-Scale Assessment of Caprock Sealing Behavior: A Case Study of the Kirtland Formation, San Juan Basin

The assessment of caprocks for geologic CO{sub 2} storage is a multi-scale endeavor. Investigation of a regional caprock - the Kirtland Formation, San Juan Basin, USA - at the pore-network scale indicates high capillary sealing capacity and low permeabilities. Core and wellscale data, however, indicate a potential seal bypass system as evidenced by multiple mineralized fractures and methane gas saturations within the caprock. Our interpretation of {sup 4}He concentrations, measured at the top and bottom of the caprock, suggests low fluid fluxes through the caprock: (1) Of the total {sup 4}He produced in situ (i.e., at the locations of sampling) by uranium and thorium decay since deposition of the Kirtland Formation, a large portion still resides in the pore fluids. (2) Simple advection-only and advection-diffusion models, using the measured {sup 4}He concentrations, indicate low permeability ({approx}10-20 m{sup 2} or lower) for the thickness of the Kirtland Formation. These findings, however, do not guarantee the lack of a large-scale bypass system. The measured data, located near the boundary conditions of the models (i.e., the overlying and underlying aquifers), limit our testing of conceptual models and the sensitivity of model parameterization. Thus, we suggest approaches for future studies to better assess the …
Date: March 15, 2011
Creator: Heath, Jason; McPherson, Brian & Dewers, Thomas
Object Type: Report
System: The UNT Digital Library
A Hierarchical Control Architecture for a PEBB-Based ILC Marx Modulator (open access)

A Hierarchical Control Architecture for a PEBB-Based ILC Marx Modulator

The idea of building power conversion systems around Power Electronic Building Blocks (PEBBs) was initiated by the U.S. Office of Naval Research in the mid 1990s. A PEBB-based design approach is advantageous in terms of power density, modularity, reliability, and serviceability. It is obvious that this approach has much appeal for pulsed power conversion including the International Linear Collider (ILC) klystron modulator application. A hierarchical control architecture has the inherent capability to support the integration of PEBBs. This has already been successfully demonstrated in a number of industrial applications in the recent past. This paper outlines the underlying concepts of a hierarchical control architecture for a PEBB-based Marx-topology ILC klystron modulator. The control in PEBB-based power conversion systems can be functionally partitioned into (three) hierarchical layers; system layer, application layer, and PEBB layer. This has been adopted here. Based on such a hierarchical partition, the interfaces are clearly identified and defined and, consequently, are easily characterised. A conceptual design of the hardware manager, executing low-level hardware oriented tasks, is detailed. In addition, the idea of prognostics is briefly discussed.
Date: December 15, 2011
Creator: Macken, K.; Burkhart, C.; Larsen, R.; Nguyen, M. N. & Olsen, J.
Object Type: Article
System: The UNT Digital Library
Insert Coil Test for HEP High Field Magnets Using YBCO Coated Conductor Tapes (open access)

Insert Coil Test for HEP High Field Magnets Using YBCO Coated Conductor Tapes

The final beam cooling stages of a Muon Collider may require DC solenoid magnets with magnetic fields of 30-50 T. In this paper we present progress in insert coil development using commercially available YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} Coated Conductor. Technological aspects covered in the development, including coil geometry, insulation, manufacturing process and testing are summarized and discussed. Test results of double pancake coils operated in liquid nitrogen and liquid helium are presented and compared with the performance of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape short samples.
Date: June 15, 2011
Creator: Lombardo, V.; Barzi, E.; Turrioni, D. & Zlobin, A. V.
Object Type: Article
System: The UNT Digital Library
Hierarchical Nanoceramics for Industrial Process Sensors (open access)

Hierarchical Nanoceramics for Industrial Process Sensors

This project developed a robust, tunable, hierarchical nanoceramics materials platform for industrial process sensors in harsh-environments. Control of material structure at multiple length scales from nano to macro increased the sensing response of the materials to combustion gases. These materials operated at relatively high temperatures, enabling detection close to the source of combustion. It is anticipated that these materials can form the basis for a new class of sensors enabling widespread use of efficient combustion processes with closed loop feedback control in the energy-intensive industries. The first phase of the project focused on materials selection and process development, leading to hierarchical nanoceramics that were evaluated for sensing performance. The second phase focused on optimizing the materials processes and microstructures, followed by validation of performance of a prototype sensor in a laboratory combustion environment. The objectives of this project were achieved by: (1) synthesizing and optimizing hierarchical nanostructures; (2) synthesizing and optimizing sensing nanomaterials; (3) integrating sensing functionality into hierarchical nanostructures; (4) demonstrating material performance in a sensing element; and (5) validating material performance in a simulated service environment. The project developed hierarchical nanoceramic electrodes for mixed potential zirconia gas sensors with increased surface area and demonstrated tailored electrocatalytic activity operable …
Date: July 15, 2011
Creator: Ruud, James, A.; Brosnan, Kristen, H.; Striker, Todd; Ramaswamy, Vidya; Aceto, Steven, C.; Gao, Yan et al.
Object Type: Report
System: The UNT Digital Library
Phase II Final Report Computer Optimization of Electron Guns (open access)

Phase II Final Report Computer Optimization of Electron Guns

This program implemented advanced computer optimization into an adaptive mesh, finite element, 3D, charged particle code. The routines can optimize electron gun performance to achieve a specified current, beam size, and perveance. It can also minimize beam ripple and electric field gradients. The magnetics optimization capability allows design of coil geometries and magnetic material configurations to achieve a specified axial magnetic field profile. The optimization control program, built into the charged particle code Beam Optics Analyzer (BOA) utilizes a 3D solid modeling package to modify geometry using design tables. Parameters within the graphical user interface (currents, voltages, etc.) can be directly modified within BOA. The program implemented advanced post processing capability for the optimization routines as well as the user. A Graphical User Interface allows the user to set up goal functions, select variables, establish ranges of variation, and define performance criteria. The optimization capability allowed development of a doubly convergent multiple beam gun that could not be designed using previous techniques.
Date: April 15, 2011
Creator: Ives, R. Lawrence; Bui, Thuc; Tran, Hien; Read, Michael; Attarian, Adam & Tallis, William
Object Type: Report
System: The UNT Digital Library
Investigations on Repository Near-Field Thermal Modeling - Repository Science/Thermal Load Management & Design Concepts (M41UF033302) (open access)

Investigations on Repository Near-Field Thermal Modeling - Repository Science/Thermal Load Management & Design Concepts (M41UF033302)

The various layers of material from the waste package (such as components of the engineered barrier system and the host rock surface) to a given distance within the rock wall at a given distance can be described as concentric circles with varying thermal properties (see Figure 5.1-1). The selected model approach examines the contributions of the waste package, axial waste package neighbors and lateral neighboring emplacement drifts (see Section 5.2.1 and Appendix H, Section 2). In clay and deep borehole media, the peak temperature is driven by the central waste package whereas, in granite and salt, the contribution to the temperature rise by adjacent (lateral) waste packages in drift or emplacement borehole lines is dominant at the time of the peak temperature. Mathematical models generated using Mathcad software provide insight into the effects of changing waste package spacing for six waste forms, namely UOX, MOX, co-extraction, new extraction, E-Chem ceramic and E-Chem metal in four different geologic media (granite, clay, salt and deep borehole). Each scenario includes thermal conductivity and diffusivity for each layer between the waste package and the host rock, dimensions of representative repository designs (such as waste package spacing, drift or emplacement borehole spacing, waste package dimensions …
Date: July 15, 2011
Creator: Sutton, M.; Blink, J. A.; Fratoni, M.; Greenberg, H. R. & Ross, A. D.
Object Type: Report
System: The UNT Digital Library
Review of Standard Tau Decays From the B-Factory Experiments (open access)

Review of Standard Tau Decays From the B-Factory Experiments

B-factories have been successfully operating for more than 8 years, providing an unprecedented data sample of e{sup +}e{sup 0} {yields} hadrons events. The BABAR and Belle experiments have in fact already collected over 550 fb{sup -1} and 800 fb{sup -1} respectively at the {Upsilon}(4s) center-of-mass (CM) energy. At this energy, the cross-section for tau production is of the same order of the cross-section for b production: {sigma}(b{bar b}) {approx} 1.1 nb {approx} {sigma}({tau}{sup +}{tau}{sup -}) {approx} 0.9 nb. For this reason, B-factories can now be considered also Tau-factories. A review of the most recent results on standard tau decays from the BABAR and Belle experiments is presented in this article.
Date: November 15, 2011
Creator: Salvatore, F. & /Royal Holloway, U. of London
Object Type: Article
System: The UNT Digital Library
Studies of the structure and function of Mms6, a bacterial protein that promotes the formation of magnetic nanoparticles (open access)

Studies of the structure and function of Mms6, a bacterial protein that promotes the formation of magnetic nanoparticles

Here we report structural and functional studies of Mms6, a biomineralization protein that can promote the formation in vitro of magnetic nanoparticles with sizes and morphologies similar to the magnetites synthesized by magnetotactic bacteria. We found the binding pattern of Mms6 to ferric ion to be two-phase and multivalent. We quantatively determined that Mms6 binds one Fe{sup 3+} with a very high affinity (K{sub d} = 10{sup -16} M). The second phase of iron binding is multivalent and cooperative with respect to iron with a K{sub d} in the {mu}M range and a stoichiometry of about 20 ferric ion per protein molecule. We found that Mms6 exists in large particles of two sizes, one consisting of 20-40 monomeric units and the other of 200 units. From proteolytic digestion, ultracentrifugation and liposome fusion studies, we found that Mms6 forms a large micellar quaternary structure with the N-terminal domain self-assembling into a uniformly sized micelle and the C-terminal domain on the surface. The two-phase iron-binding pattern may be relevant to iron crystal formation. We propose that the first high affinity phase may stabilize a new conformation of the C-terminal domain that allows interaction with other C-terminal domains leading to a structural change …
Date: May 15, 2011
Creator: Wang, Lijun
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Thermal dissociation behavior and dissociation enthalpies of methane-carbon dioxide mixed hydrates (open access)

Thermal dissociation behavior and dissociation enthalpies of methane-carbon dioxide mixed hydrates

Replacement of methane with carbon dioxide in hydrate has been proposed as a strategy for geologic sequestration of carbon dioxide (CO{sub 2}) and/or production of methane (CH{sub 4}) from natural hydrate deposits. This replacement strategy requires a better understanding of the thermodynamic characteristics of binary mixtures of CH{sub 4} and CO{sub 2} hydrate (CH{sub 4}-CO{sub 2} mixed hydrates), as well as thermophysical property changes during gas exchange. This study explores the thermal dissociation behavior and dissociation enthalpies of CH{sub 4}-CO{sub 2} mixed hydrates. We prepared CH{sub 4}-CO{sub 2} mixed hydrate samples from two different, well-defined gas mixtures. During thermal dissociation of a CH{sub 4}-CO{sub 2} mixed hydrate sample, gas samples from the head space were periodically collected and analyzed using gas chromatography. The changes in CH{sub 4}-CO{sub 2} compositions in both the vapor phase and hydrate phase during dissociation were estimated based on the gas chromatography measurements. It was found that the CO{sub 2} concentration in the vapor phase became richer during dissociation because the initial hydrate composition contained relatively more CO{sub 2} than the vapor phase. The composition change in the vapor phase during hydrate dissociation affected the dissociation pressure and temperature; the richer CO{sub 2} in the vapor …
Date: February 15, 2011
Creator: Kwon, T.H.; Kneafsey, T.J. & Rees, E.V.L.
Object Type: Article
System: The UNT Digital Library
PROJECT-SPECIFIC TYPE A VERIFICATION FOR THE BROOKHAVEN GRAPHITE RESEARCH REACTOR ENGINEERED CAP, BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK DCN 5098-SR-07-0 (open access)

PROJECT-SPECIFIC TYPE A VERIFICATION FOR THE BROOKHAVEN GRAPHITE RESEARCH REACTOR ENGINEERED CAP, BROOKHAVEN NATIONAL LABORATORY UPTON, NEW YORK DCN 5098-SR-07-0

The Oak Ridge Institute for Science and Education (ORISE) has reviewed the project documentation and data for the Brookhaven Graphite Research Reactor (BGRR) Engineered Cap at Brookhaven National Laboratory (BNL) in Upton, New York. The Brookhaven Science Associates (BSA) have completed removal of affected soils and performed as-left surveys by BSA associated with the BGRR Engineered Cap. Sample results have been submitted, as required, to demonstrate that remediation efforts comply with the cleanup goal of {approx}15 mrem/yr above background to a resident in 50 years (BNL 2011a).
Date: July 15, 2011
Creator: Harpenau, Evan
Object Type: Report
System: The UNT Digital Library
China's Energy and Carbon Emissions Outlook to 2050 (open access)

China's Energy and Carbon Emissions Outlook to 2050

As a result of soaring energy demand from a staggering pace of economic expansion and the related growth of energy-intensive industry, China overtook the United States to become the world's largest contributor to CO{sub 2} emissions in 2007. At the same time, China has taken serious actions to reduce its energy and carbon intensity by setting both a short-term energy intensity reduction goal for 2006 to 2010 as well as a long-term carbon intensity reduction goal for 2020. This study presents a China Energy Outlook through 2050 that assesses the role of energy efficiency policies in transitioning China to a lower emission trajectory and meeting its intensity reduction goals. Over the past few years, LBNL has established and significantly enhanced its China End-Use Energy Model which is based on the diffusion of end-use technologies and other physical drivers of energy demand. This model presents an important new approach for helping understand China's complex and dynamic drivers of energy consumption and implications of energy efficiency policies through scenario analysis. A baseline ('Continued Improvement Scenario') and an alternative energy efficiency scenario ('Accelerated Improvement Scenario') have been developed to assess the impact of actions already taken by the Chinese government as well as …
Date: February 15, 2011
Creator: Zhou, Nan; Fridley, David; McNeil, Michael; Zheng, Nina; Ke, Jing & Levine, Mark
Object Type: Report
System: The UNT Digital Library
Mesoporous silica nanoparticles as smart and safe devices for regulating blood biomolecule levels (open access)

Mesoporous silica nanoparticles as smart and safe devices for regulating blood biomolecule levels

Stimuli-responsive end-capped MSN materials are promising drug carriers that securely deliver a large payload of drug molecules without degradation or premature release. A general review of the recent progress in this field is presented, including a summary of a series of hard and soft caps for drug encapsulation and a variety of internal and external stimuli for controlled release of different therapeutics, a discussion of the biocompatibility of MSN both in vitro and in vivo, and a description of the sophisticated stimuli-responsive systems with novel capping agents and controlled release mechanism. The unique internal and external surfaces of MSN were utilized for the development of a glucose-responsive double delivery system end-capped with insulin. This unique system consists of functionalized MSNs capable of releasing insulin when the concentration of sugar in blood exceeds healthy levels. The insulin-free nanoparticles are then up taken by pancreatic cells, and release inside of them another biomolecule that stimulates the production of more insulin. The in vivo application of this system for the treatment of diabetes requires further understanding on the biological behaviors of these nanoparticles in blood vessels. The research presented in this dissertation demonstrated the size and surface effects on the interaction of MSNs …
Date: May 15, 2011
Creator: Zhao, Yan
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Unitarity Constraints on Asymmetric Freeze-In (open access)

Unitarity Constraints on Asymmetric Freeze-In

This paper considers unitarity and CPT constraints on asymmetric freeze-in, the use of freeze-in to store baryon number in a dark sector. In this scenario, Sakharov's out of equilibrium condition is satisfied by placing the visible and hidden sectors at different temperatures while a net visible baryon number is produced by storing negative baryon number in a dark sector. It is shown that unitarity and CPT lead to unexpected cancellations. In particular, the transfer of baryon number cancels completely at leading order. This note has shown that if two sectors are in thermal equilibrium with themselves, but not with each other, then the leading effect transferring conserved quantities between the two sectors is of order the the weak coupling connecting them to the third power. When freeze-in is used to produce a net baryon number density, the leading order effect comes from {Omicron}({lambda}{sup 3}) diagrams where the intermediate state that goes on-shell has a different visible baryon number than the final state visible baryon number. Models in which the correct baryon number is generated with freeze-in as the dominant source of abundance, typically require {lambda} {approx}> 10{sup -6} and m{sub bath} {approx}> TeV. m{sub bath} is the mass of the …
Date: August 15, 2011
Creator: Hook, Anson
Object Type: Article
System: The UNT Digital Library
New Prospects in High Energy Astrophysics (open access)

New Prospects in High Energy Astrophysics

Recent discoveries using TeV, X-ray and radio telescopes as well as Ultra High Energy Cosmic Ray arrays are leading to new insights into longstanding puzzles in high energy astrophysics. Many of these insights come from combining observations throughout the electromagnetic and other spectra as well as evidence assembled from different types of source to propose general principles. Issues discussed in this general overview include methods of accelerating relativistic particles, and amplifying magnetic field, the dynamics of relativistic outflows and the nature of the prime movers that power them. Observational approaches to distinguishing hadronic, leptonic and electromagnetic outflows and emission mechanisms are discussed along with probes of the velocity field and the confinement mechanisms. Observations with GLAST promise to be very prescriptive for addressing these problems.
Date: November 15, 2011
Creator: Blandford, Roger
Object Type: Article
System: The UNT Digital Library
Built-in and Induced Polarization Across LaAlO3/SrTiO3 Heterojunctions (open access)

Built-in and Induced Polarization Across LaAlO3/SrTiO3 Heterojunctions

Ionic crystals terminated at oppositely charged polar surfaces are inherently unstable and expected to undergo surface reconstructions to maintain electrostatic stability. Essentially, an electric field that arises between oppositely charged atomic planes gives rise to a built-in potential that diverges with thickness. Here we present evidence of such a built-in potential across polar LaAlO{sub 3} thin films grown on SrTiO{sub 3} substrates, a system well known for the electron gas that forms at the interface. By performing tunneling measurements between the electron gas and metallic electrodes on LaAlO{sub 3} we measure a built-in electric field across LaAlO{sub 3} of 80.1 meV/{angstrom}. Additionally, capacitance measurements reveal the presence of an induced dipole moment across the heterostructure. We forsee use of the ionic built-in potential as an additional tuning parameter in both existing and novel device architectures, especially as atomic control of oxide interfaces gains widespread momentum.
Date: August 15, 2011
Creator: Guneeta, Singh-Bhalla
Object Type: Article
System: The UNT Digital Library
2011 Organometallic Chemistry (July 10-15, 2011, Salve Regina University, Newport, RI) (open access)

2011 Organometallic Chemistry (July 10-15, 2011, Salve Regina University, Newport, RI)

Organometallic chemistry has played and will continue to play a significant role in helping us understand the way bonds are made or broken in the presence of a transition metal complex. Current challenges range from the efficient exploitation of energy resources to the creative use of natural and artificial enzymes. Most of the new advances in the area are due to our extended understanding of processes at a molecular level due to new mechanistic studies, techniques to detect reaction intermediates and theory. The conference will bring the most recent advances in the field including nanocatalysis, surface organometallic chemistry, characterization techniques, new chemical reactivity and theoretical approaches along with applications to organic synthesis and the discovery of new materials. The Conference will bring together a collection of investigators who are at the forefront of their field, and will provide opportunities for junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. Six outstanding posters will be selected for short talks. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to …
Date: July 15, 2011
Creator: Bunel, Dr. Emilio
Object Type: Article
System: The UNT Digital Library
Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides (open access)

Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides

Although the parent iron-based pnictides and chalcogenides are itinerant antiferromagnets, the use of local moment picture to understand their magnetic properties is still widespread. We study magnetic Raman scattering from a local moment perspective for various quantum spin models proposed for this new class of superconductors. These models vary greatly in the level of magnetic frustration and show a vastly different two-magnon Raman response. Light scattering by two-magnon excitations thus provides a robust and independent measure of the underlying spin interactions. In accord with other recent experiments, our results indicate that the amount of magnetic frustration in these systems may be small.
Date: August 15, 2011
Creator: Chen, C. C.
Object Type: Article
System: The UNT Digital Library
ADDING REALISM TO NUCLEAR MATERIAL DISSOLVING ANALYSIS (open access)

ADDING REALISM TO NUCLEAR MATERIAL DISSOLVING ANALYSIS

Two new criticality modeling approaches have greatly increased the efficiency of dissolver operations in H-Canyon. The first new approach takes credit for the linear, physical distribution of the mass throughout the entire length of the fuel assembly. This distribution of mass is referred to as the linear density. Crediting the linear density of the fuel bundles results in using lower fissile concentrations, which allows higher masses to be charged to the dissolver. Also, this approach takes credit for the fact that only part of the fissile mass is wetted at a time. There are multiple assemblies stacked on top of each other in a bundle. On average, only 50-75% of the mass (the bottom two or three assemblies) is wetted at a time. This means that only 50-75% (depending on operating level) of the mass is moderated and is contributing to the reactivity of the system. The second new approach takes credit for the progression of the dissolving process. Previously, dissolving analysis looked at a snapshot in time where the same fissile material existed both in the wells and in the bulk solution at the same time. The second new approach models multiple consecutive phases that simulate the fissile material …
Date: August 15, 2011
Creator: Williamson, B.
Object Type: Article
System: The UNT Digital Library
National Level Co-Control Study of the Targets for Energy Intensity and Sulfur Dioxide in China (open access)

National Level Co-Control Study of the Targets for Energy Intensity and Sulfur Dioxide in China

Since 2006, China has set goals of reducing energy intensity, emissions, and pollutants in multiple guidelines and in the Five Year Plans. Various strategies and measures have then been taken to improve the energy efficiency in all sectors and to reduce pollutants. Since controlling energy, CO{sub 2} emissions, and pollutants falls under the jurisdiction of different government agencies in China, many strategies are being implemented to fulfill only one of these objectives. Co-controls or integrated measures could simultaneously reduce greenhouse gas (GHG) emissions and criteria air pollutant emissions. The targets could be met in a more cost effective manner if the integrated measures can be identified and prioritized. This report provides analysis and insights regarding how these targets could be met via co-control measures focusing on both CO{sub 2} and SO{sub 2} emissions in the cement, iron &steel, and power sectors to 2030 in China. An integrated national energy and emission model was developed in order to establish a baseline scenario that was used to assess the impact of actions already taken by the Chinese government as well as planned and expected actions. In addition, CO{sub 2} mitigation scenarios and SO{sub 2} control scenarios were also established to evaluate the …
Date: October 15, 2011
Creator: Zhou, Nan; Price, Lynn; Zheng, Nina; Ke, Jing & Hasanbeigi, Ali
Object Type: Report
System: The UNT Digital Library
Development of High Temperature Capacitor Technology and Manufacturing Capability (open access)

Development of High Temperature Capacitor Technology and Manufacturing Capability

The goal of the Development of High Temperature Capacitor Technology and Manufacturing Capability program was to mature a production-ready supply chain for reliable 250°C FPE (fluorinated polyester) film capacitors by 2011. These high-temperature film capacitors enable both the down hole drilling and aerospace industries by enabling a variety of benefits including: − Deeper oil exploration in higher temperature and pressure environments − Enabling power electronic and control equipment to operate in higher temperature environments − Enabling reduced cooling requirements of electronics − Increasing reliability and life of capacitors operating below rated temperature − Enabling capacitors to handle higher electrical losses without overheating. The key challenges to bringing the FPE film capacitors to market have been manufacturing challenges including: − FPE Film is difficult to handle and wind, resulting in poor yields − Voltage breakdown strength decreases when the film is wound into capacitors (~70% decrease) − Encapsulation technologies must be improved to enable higher temperature operation − Manufacturing and test cycle time is very long As a direct result of this program most of the manufacturing challenges have been met. The FPE film production metalization and winding yield has increased to over 82% from 70%, and the voltage breakdown strength …
Date: May 15, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Raman Investigation of The Uranium Compounds U3O8, UF4, UH3 and UO3 under Pressure at Room Temperature (open access)

Raman Investigation of The Uranium Compounds U3O8, UF4, UH3 and UO3 under Pressure at Room Temperature

Our current state-of-the-art X-ray diffraction experiments are primarily sensitive to the position of the uranium atom. While the uranium - low-Z element bond (such as U-H or U-F) changes under pressure and temperature the X-ray diffraction investigations do not reveal information about the bonding or the stoichiometry. Questions that can be answered by Raman spectroscopy are (i) whether the bonding strength changes under pressure, as observed by either blue- or red-shifted peaks of the Raman active bands in the spectrum and (ii) whether the low-Z element will eventually be liberated and leave the host lattice, i.e. do the fluorine, oxygen, or hydrogen atoms form dimers after breaking the bond to the uranium atom. Therefore Raman spectra were also collected in the range where those decomposition products would appear. Raman is particularly well suited to these types of investigations due to its sensitivity to trace amounts of materials. One challenge for Raman investigations of the uranium compounds is that they are opaque to visible light. They absorb the incoming radiation and quickly heat up to the point of decomposition. This has been dealt with in the past by keeping the incoming laser power to very low levels on the tens of …
Date: December 15, 2011
Creator: Lipp, M. J.; Jenei, Z.; Park-Klepeis, J. & Evans, W. J.
Object Type: Report
System: The UNT Digital Library
USE OF THE AERIAL MEASUREMENT SYSTEM HELICOPTER EMERGENCY RESPONSE ACQUISITION SYSTEMS WITH GEOGRAPHIC INFORMATION SYSTEM FOR RADIOACTIVE SOIL REMEDIATION - [11504] (open access)

USE OF THE AERIAL MEASUREMENT SYSTEM HELICOPTER EMERGENCY RESPONSE ACQUISITION SYSTEMS WITH GEOGRAPHIC INFORMATION SYSTEM FOR RADIOACTIVE SOIL REMEDIATION - [11504]

The Aerial Measurement System (AMS) Helicopter Emergency Response Acquisition System provides a thorough and economical means to identify and characterize the contaminants for large area radiological surveys. The helicopter system can provide a 100-percent survey of an area that qualifies as a scoping survey under the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) methodology. If the sensitivity is adequate when compared to the clean up values, it may also be used for the characterization survey. The data from the helicopter survey can be displayed and manipulated to provide invaluable data during remediation activities.
Date: February 15, 2011
Creator: CT, BROCK
Object Type: Article
System: The UNT Digital Library
Reassessing Wind Potential Estimates for India: Economic and Policy Implications (open access)

Reassessing Wind Potential Estimates for India: Economic and Policy Implications

We assess developable on-shore wind potential in India at three different hub-heights and under two sensitivity scenarios – one with no farmland included, the other with all farmland included. Under the “no farmland included” case, the total wind potential in India ranges from 748 GW at 80m hub-height to 976 GW at 120m hub-height. Under the “all farmland included” case, the potential with a minimum capacity factor of 20 percent ranges from 984 GW to 1,549 GW. High quality wind energy sites, at 80m hub-height with a minimum capacity factor of 25 percent, have a potential between 253 GW (no farmland included) and 306 GW (all farmland included). Our estimates are more than 15 times the current official estimate of wind energy potential in India (estimated at 50m hub height) and are about one tenth of the official estimate of the wind energy potential in the US.
Date: September 15, 2011
Creator: Phadke, Amol; Bharvirkar, Ranjit & Khangura, Jagmeet
Object Type: Report
System: The UNT Digital Library
FINAL PROJECT REPORT: A Geophysical Characterization & Monitoring Strategy for Determining Hydrologic Processes in the Hyporheic Corridor at the Hanford 300-Area (open access)

FINAL PROJECT REPORT: A Geophysical Characterization & Monitoring Strategy for Determining Hydrologic Processes in the Hyporheic Corridor at the Hanford 300-Area

The primary objective of this research was to advance the prediction of solute transport between the Uranium contaminated Hanford aquifer and the Columbia River at the Hanford 300 Area by improving understanding of how fluctuations in river stage, combined with subsurface heterogeneity, impart spatiotemporal complexity to solute exchange along the Columbia River corridor. Our work explored the use of continuous waterborne electrical imaging (CWEI), in conjunction with fiber-optic distributed temperature sensor (FO-DTS) and time-lapse resistivity monitoring, to improve the conceptual model for how groundwater/surface water exchange regulates uranium transport. We also investigated how resistivity and induced polarization can be used to generate spatially rich estimates of the variation in depth to the Hanford-Ringold (H-R) contact between the river and the 300 Area Integrated Field Research Challenge (IFRC) site. Inversion of the CWEI datasets (a data rich survey containing ~60,000 measurements) provided predictions of the distributions of electrical resistivity and polarizability, from which the spatial complexity of the primary hydrogeologic units along the river corridor was reconstructed. Variation in the depth to the interface between the overlying coarse-grained, high permeability Hanford Formation and the underlying finer-grained, less permeable Ringold Formation, an important contact that limits vertical migration of contaminants, has been …
Date: August 15, 2011
Creator: Slater, Lee
Object Type: Report
System: The UNT Digital Library