Intent, Capability and Opportunity: A Holistic Approach to Addressing Proliferation as a Risk Management Issue (open access)

Intent, Capability and Opportunity: A Holistic Approach to Addressing Proliferation as a Risk Management Issue

Currently, proliferation risk assessment models are designed to evaluate only a portion of the overall risk, focusing exclusively on either technological or social factors to determine the extent of a threat. Many of these models are intended to act as a means of predicting proliferation potential rather than assessing the system as a whole, ignoring the ability to enhance mitigating factors and manage, rather just establish the presence of, the threat. While the information garnered through these forms of analysis is necessary, it remains incomplete. By incorporating political, social, economic and technical capabilities as well as human factors such as intent into a single, multi-faceted risk management model, proliferation risk can be evaluated more effectively. Framing this information around how to improve and expand the Regime already in place and establishing where there are gaps in the system allows for a more complete approach to risk management, mitigation and resource allocation. The research conducted here seeks to combine all three elements (intent, capability and opportunity) in a comprehensive evaluation which incorporates an assessment of state-level variables, possible proliferation pathways and technical capability. Each portion of the analysis is carried out independently then combined to illustrate the full scope of a …
Date: July 1, 2011
Creator: Rynes, Amanda & Bjornard, Trond
Object Type: Article
System: The UNT Digital Library
SUMMARY REPORT FOR ZINC 65 CONTAMINATION CONTROL (open access)

SUMMARY REPORT FOR ZINC 65 CONTAMINATION CONTROL

Radioactive zinc, {sup 65}Zn, was detected after extraction of 215 TPBARs in from TVA reactor fuel cycle 6. A team consisting of Tritium Engineering, Tritium Operations, Tritium Radiation Control, and Savannah River National Laboratory personnel evaluated the risk and response and developed short, medium and long term goals for contamination control. One of the goals was incorporated into site Performance Based Incentive CO 3.4, to optimize the filter geometry and operating conditions for the Tritium Extraction Facility. This goal included a scoping study to determine if the contamination could be contained within the high radiation environment of the furnace module as well. In order to optimize the filters studies were conducted to independently evaluate the effect of pore size on pumping efficiency and zinc trapping efficiency (1). A study was also conducted to evaluate the effect of temperature on the trapping efficiency and adhesion (2). In addition, the potential for chemically trapping zinc in the lithium trap was evaluated using a thermodynamic study (3) followed by preliminary experimental testing (4). Based on the work that was completed it is determined that a 20 {mu}m filter heated to between 120 and 200 C will act as an effective physical trap for …
Date: July 14, 2011
Creator: Korinko, P.
Object Type: Report
System: The UNT Digital Library
MIX and Instability Growth from Oblique Shock (open access)

MIX and Instability Growth from Oblique Shock

We have studied the formation and evolution of shock-induced mix resulting from interface features in a divergent cylindrical geometry. In this research a cylindrical core of high-explosive was detonated to create an oblique shock wave and accelerate the interface. The interfaces studied were between the high-explosive/aluminum, aluminum/plastic, and finally plastic/air. Pre-emplaced surface features added to the aluminum were used to modify this interface. Time sequence radiographic imaging quantified the resulting instability formation from the growth phase to over 60 {micro}s post-detonation. Thus allowing the study of the onset of mix and evolution to turbulence. The plastic used here was porous polyethylene. Radiographic image data are compared with numerical simulations of the experiments.
Date: July 22, 2011
Creator: Molitoris, J D; Batteux, J D; Garza, R G; Tringe, J W; Souers, P C & Forbes, J W
Object Type: Article
System: The UNT Digital Library
MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Data Sets (Revision 2) (open access)

MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Data Sets (Revision 2)

This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility microwave radiometer (MWR) Retrieval (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).
Date: July 25, 2011
Creator: Gaustad, K. L.; Turner, D. D. & McFarlane, S. A.
Object Type: Report
System: The UNT Digital Library
Search for $B_s \to \mu^+\mu^-$ and $B_d \to \mu^+\mu^-$ Decays with CDF II (open access)

Search for $B_s \to \mu^+\mu^-$ and $B_d \to \mu^+\mu^-$ Decays with CDF II

A search has been performed for B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} and B{sup 0} {yields} {mu}{sup +}{mu}{sup -} decays using 7 fb{sup -1} of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B{sup 0} candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of {Beta}(B{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 6.0 x 10{sup -9} at 95% confidence level. We observe an excess of B{sub s}{sup 0} candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} could produce such an excess or larger is 1.9%. These data are used to determine {Beta}(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -}) = (1.8{sub -0.9}{sup +1.1}) x 10{sup -8} and provide an upper limit of {Beta}(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 4.0 x 10{sup -8} at 95% confidence level.
Date: July 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type: Article
System: The UNT Digital Library
SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELIMINARY DESIGN HAZARD ANALYSIS SUPPLEMENT 1 (open access)

SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELIMINARY DESIGN HAZARD ANALYSIS SUPPLEMENT 1

This 'What/If' Hazards Analysis addresses hazards affecting the Sludge Treatment Project Engineered Container Retrieval and Transfer System (ECRTS) NPH and external events at the preliminary design stage. In addition, the hazards of the operation sequence steps for the mechanical handling operations in preparation of Sludge Transport and Storage Container (STSC), disconnect STSC and prepare STSC and Sludge Transport System (STS) for shipping are addressed.
Date: July 18, 2011
Creator: GR, FRANZ & RH, MEICHLE
Object Type: Report
System: The UNT Digital Library

Impact of Lithium Availability on Vehicle Electrification

This presentation discusses the relationship between electric drive vehicles and the availability of lithium.
Date: July 1, 2011
Creator: Neubauer, J.
Object Type: Presentation
System: The UNT Digital Library
NA-42 TI Shared Software Component Library FY2011 Final Report (open access)

NA-42 TI Shared Software Component Library FY2011 Final Report

The NA-42 TI program initiated an effort in FY2010 to standardize its software development efforts with the long term goal of migrating toward a software management approach that will allow for the sharing and reuse of code developed within the TI program, improve integration, ensure a level of software documentation, and reduce development costs. The Pacific Northwest National Laboratory (PNNL) has been tasked with two activities that support this mission. PNNL has been tasked with the identification, selection, and implementation of a Shared Software Component Library. The intent of the library is to provide a common repository that is accessible by all authorized NA-42 software development teams. The repository facilitates software reuse through a searchable and easy to use web based interface. As software is submitted to the repository, the component registration process captures meta-data and provides version control for compiled libraries, documentation, and source code. This meta-data is then available for retrieval and review as part of library search results. In FY2010, PNNL and staff from the Remote Sensing Laboratory (RSL) teamed up to develop a software application with the goal of replacing the aging Aerial Measuring System (AMS). The application under development includes an Advanced Visualization and Integration …
Date: July 21, 2011
Creator: Knudson, Christa K.; Rutz, Frederick C. & Dorow, Kevin E.
Object Type: Report
System: The UNT Digital Library
High efficiency multilayer blazed gratings for EUV and soft X-rays: Recent developments (open access)

High efficiency multilayer blazed gratings for EUV and soft X-rays: Recent developments

Multilayer coated blazed gratings with high groove density are the best candidates for use in high resolution EUV and soft x-ray spectroscopy. Theoretical analysis shows that such a grating can be potentially optimized for high dispersion and spectral resolution in a desired high diffraction order without significant loss of diffraction efficiency. In order to realize this potential, the grating fabrication process should provide a perfect triangular groove profile and an extremely smooth surface of the blazed facets. Here we report on recent progress achieved at the Advanced Light Source (ALS) in fabrication of high quality multilayer coated blazed gratings. The blazed gratings were fabricated using scanning beam interference lithography followed by wet anisotropic etching of silicon. A 200 nm period grating coated with a Mo/Si multilayer composed with 30 bi-layers demonstrated an absolute efficiency of 37.6percent in the 3rd diffraction order at 13.6 nm wavelength. The groove profile of the grating was thoroughly characterized with atomic force microscopy before and after the multilayer deposition. The obtained metrology data were used for simulation of the grating efficiency with the vector electromagnetic PCGrate-6.1 code. The simulations showed that smoothing of the grating profile during the multilayer deposition is the main reason for …
Date: July 26, 2011
Creator: Voronov, Dmitriy; Ahn, Minseung; Anderson, Erik; Cambie, Rossana; Chang, Chih-Hao; Goray, Leonid et al.
Object Type: Article
System: The UNT Digital Library
Catalytic Process for the Conversion of Coal-derived Syngas to Ethanol (open access)

Catalytic Process for the Conversion of Coal-derived Syngas to Ethanol

The catalytic conversion of coal-derived syngas to C{sub 2+} alcohols and oxygenates has attracted great attention due to their potential as chemical intermediates and fuel components. This is particularly true of ethanol, which can serve as a transportation fuel blending agent, as well as a hydrogen carrier. A thermodynamic analysis of CO hydrogenation to ethanol that does not allow for byproducts such as methane or methanol shows that the reaction: 2 CO + 4 H{sub 2} {yields} C{sub 2}H{sub 5}OH + H{sub 2}O is thermodynamically favorable at conditions of practical interest (e.g,30 bar, {approx}< 250 C). However, when methane is included in the equilibrium analysis, no ethanol is formed at any conditions even approximating those that would be industrially practical. This means that undesired products (primarily methane and/or CO{sub 2}) must be kinetically limited. This is the job of a catalyst. The mechanism of CO hydrogenation leading to ethanol is complex. The key step is the formation of the initial C-C bond. Catalysts that are selective for EtOH can be divided into four classes: (a) Rh-based catalysts, (b) promoted Cu catalysts, (c) modified Fischer-Tropsch catalysts, or (d) Mo-sulfides and phosphides. This project focuses on Rh- and Cu-based catalysts. The logic …
Date: July 29, 2011
Creator: Spivery, James; Harrison, Doug; Earle, John; Goodwin, James; Bruce, David; Mo, Xunhau et al.
Object Type: Report
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
RF Test Results from Cryomodule 1 at the Fermilab SRF Beam Test Facility (open access)

RF Test Results from Cryomodule 1 at the Fermilab SRF Beam Test Facility

Powered operation of Cryomodule 1 (CM-1) at the Fermilab SRF Beam Test Facility began in late 2010. Since then a series of tests first on the eight individual cavities and then the full cryomodule have been performed. We report on the results of these tests and lessons learned which will have an impact on future module testing at Fermilab. Since November 2010 Cryomodule 1 has been operating at 2 Kelvin. After evaluating each of the eight cavities while individually powered, the entire module has recently been powered and peak operation determined as shown in Figure 4. Several more weeks of measurements are planned before the module is warmed up, removed and replaced with Cryomodule 2 now under assembly at Fermilab.
Date: July 26, 2011
Creator: Harms, E.; Carlson, K.; Chase, B.; Cullerton, E.; Hocker, A.; Jensen, C. et al.
Object Type: Article
System: The UNT Digital Library
Triple Modulator-Chicane Scheme for Seeding Sub-Nanometer X-Ray Free Electron Lasers (open access)

Triple Modulator-Chicane Scheme for Seeding Sub-Nanometer X-Ray Free Electron Lasers

We propose a novel triple modulator-chicane (TMC) scheme to convert external input seed to shorter wavelengths. In the scheme high power seed lasers are used in the first and third modulator while only very low power seed is used in the second modulator. By properly choosing the parameters of the lasers and chicanes, we show that ultrahigh harmonics can be generated in the TMC scheme while simultaneously keeping the energy spread growth much smaller than beam's initial slice energy spread. As an example we show the feasibility of generating significant bunching at 1 nm and below from a low power ({approx} 100 kW) high harmonic generation seed at 20 nm assisted by two high power ({approx} 100 MW) UV lasers at 200 nm while keeping the energy spread growth within 40%. The supreme up-frequency conversion efficiency of the proposed TMC scheme together with its unique advantage in maintaining beam energy spread opens new opportunities for generating fully coherent x-rays at sub-nanometer wavelength from external seeds.
Date: July 6, 2011
Creator: Xiang, Dao & Stupakov, Gennady
Object Type: Article
System: The UNT Digital Library
Analysis of the Tank 5F Feed and Bleed Residual Solids (open access)

Analysis of the Tank 5F Feed and Bleed Residual Solids

Savannah River Remediation (SRR) is preparing Tank 5F for closure. As part of Tank 5F Closure Mechanical Cleaning, SRR conducted a 'Feed and Bleed' process in Tank 5F. Following this 'Feed and Bleed' Mechanical Cleaning in Tank 5F, SRR collected two tank heel samples (referred to as sample 1 and sample 2) under Riser 5 to determine the composition of the material remaining in the tanks. This document describes sample analysis results. The conclusions from this analysis follow. (1) The anions measured all had a concentration less than 250 mg/kg, except for oxalate, which had a concentration of 2100-2400 mg/kg. (2) The measured cations with the highest concentration were iron (432,000-519,000 mg/kg), nickel (54,600-69,300 mg/kg), and manganese (35,200-42,100 mg/kg). All other cations measured less than 13,000 mg/kg. (3) The radionuclides present in the highest concentration are {sup 90}Sr (3.0 x 10{sup 10} dpm/g), {sup 137}Cs (6.8 x 10{sup 8} dpm/g), and {sup 241}Am (1.4 x 10{sup 8} - 1.8 x 10{sup 8} dpm/g). (4) The particle size analysis shows a large fraction of particles greater than 100 {micro}.
Date: July 7, 2011
Creator: Poirier, M.; Diprete, D.: Coleman, C. & Washington, A.
Object Type: Report
System: The UNT Digital Library
Utility-scale grid-tied PV inverter reliability workshop summary report. (open access)

Utility-scale grid-tied PV inverter reliability workshop summary report.

A key to the long-term success of the photovoltaic (PV) industry is confidence in the reliability of PV systems. Inverters are the most commonly noted cause of PV system incidents triggered in the field. While not all of these incidents are reliability-related or even necessarily failures, they still result in a loss of generated power. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a Utility-Scale Grid-Tied Inverter Reliability Workshop in Albuquerque, New Mexico, January 27-28, 2011. The workshop addressed the reliability of large (100-kilowatt+) grid-tied inverters and the implications when such inverters fail, evaluated inverter codes and standards, and provided discussion about opportunities to enhance inverter reliability. This report summarizes discussions and presentations from the workshop and identifies opportunities for future efforts.
Date: July 1, 2011
Creator: Granata, Jennifer E.; Quintana, Michael A.; Tasca, Coryne Adelle (SRA International, Inc., Fairfax, VA) & Atcitty, Stanley
Object Type: Report
System: The UNT Digital Library
Integrating Renewable Energy Requirements Into Building Energy Codes (open access)

Integrating Renewable Energy Requirements Into Building Energy Codes

This report evaluates how and when to best integrate renewable energy requirements into building energy codes. The basic goals were to: (1) provide a rough guide of where we’re going and how to get there; (2) identify key issues that need to be considered, including a discussion of various options with pros and cons, to help inform code deliberations; and (3) to help foster alignment among energy code-development organizations. The authors researched current approaches nationally and internationally, conducted a survey of key stakeholders to solicit input on various approaches, and evaluated the key issues related to integration of renewable energy requirements and various options to address those issues. The report concludes with recommendations and a plan to engage stakeholders. This report does not evaluate whether the use of renewable energy should be required on buildings; that question involves a political decision that is beyond the scope of this report.
Date: July 1, 2011
Creator: Kaufmann, John R.; Hand, James R. & Halverson, Mark A.
Object Type: Report
System: The UNT Digital Library
A model for improving microbial biofuel production using a synthetic feedback loop (open access)

A model for improving microbial biofuel production using a synthetic feedback loop

Cells use feedback to implement a diverse range of regulatory functions. Building synthetic feedback control systems may yield insight into the roles that feedback can play in regulation since it can be introduced independently of native regulation, and alternative control architectures can be compared. We propose a model for microbial biofuel production where a synthetic control system is used to increase cell viability and biofuel yields. Although microbes can be engineered to produce biofuels, the fuels are often toxic to cell growth, creating a negative feedback loop that limits biofuel production. These toxic effects may be mitigated by expressing efflux pumps that export biofuel from the cell. We developed a model for cell growth and biofuel production and used it to compare several genetic control strategies for their ability to improve biofuel yields. We show that controlling efflux pump expression directly with a biofuel-responsive promoter is a straight forward way of improving biofuel production. In addition, a feed forward loop controller is shown to be versatile at dealing with uncertainty in biofuel production rates.
Date: July 14, 2011
Creator: Dunlop, Mary; Keasling, Jay & Mukhopadhyay, Aindrila
Object Type: Article
System: The UNT Digital Library
Solar 2 Green Energy, Arts & Education Center (open access)

Solar 2 Green Energy, Arts & Education Center

The Solar 2 Green Energy, Arts and Education Center is an 8,000 sq.ft. demonstration project that will be constructed to Platinum LEED certification and will be the first carbon-neutral, net-zero energy use public building in New York City, giving it local and national appeal. Employing “green” building features and holistic engineering practices throughout its international award-winning design, Solar 2 will be powered by a 90kW photovoltaic (PV) array in conjunction with a geothermal heating and cooling system and a high efficient design that seeks to reduce the overall energy load of the building. Solar 2 will replace our current 500 sq.ft. prototype facility - known as Solar 1 - as the educational and cultural centerpiece of a five-block public greenway on the East River in Stuyvesant Cove Park, located along two acres of public riverfront on a newly reclaimed, former brownfield in lower Manhattan. Designed as a public-use complex for year-round environmental education exhibits and onsite activities for all ages and backgrounds, Solar 2 will demonstrate energy-efficiency technologies and sustainable environmental practices available now to all urban residents, eco-tourists, teachers, and students alike. Showcasing one of Solar 2’s most striking design elements is the PV roof array with a café …
Date: July 18, 2011
Creator: Paquette, Jamie C. & Collins, Christopher J.
Object Type: Text
System: The UNT Digital Library
GATE Center of Excellence at UAB in Lightweight Materials for Automotive Applications (open access)

GATE Center of Excellence at UAB in Lightweight Materials for Automotive Applications

This report summarizes the accomplishments of the UAB GATE Center of Excellence in Lightweight Materials for Automotive Applications. The first Phase of the UAB DOE GATE center spanned the period 2005-2011. The UAB GATE goals coordinated with the overall goals of DOE's FreedomCAR and Vehicles Technologies initiative and DOE GATE program. The FCVT goals are: (1) Development and validation of advanced materials and manufacturing technologies to significantly reduce automotive vehicle body and chassis weight without compromising other attributes such as safety, performance, recyclability, and cost; (2) To provide a new generation of engineers and scientists with knowledge and skills in advanced automotive technologies. The UAB GATE focused on both the FCVT and GATE goals in the following manner: (1) Train and produce graduates in lightweight automotive materials technologies; (2) Structure the engineering curricula to produce specialists in the automotive area; (3) Leverage automotive related industry in the State of Alabama; (4) Expose minority students to advanced technologies early in their career; (5) Develop innovative virtual classroom capabilities tied to real manufacturing operations; and (6) Integrate synergistic, multi-departmental activities to produce new product and manufacturing technologies for more damage tolerant, cost-effective, and lighter automotive structures.
Date: July 31, 2011
Creator: unknown
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
NV Energy Solar Integration Study: Cycling and Movements of Conventional Generators for Balancing Services (open access)

NV Energy Solar Integration Study: Cycling and Movements of Conventional Generators for Balancing Services

With an increasing penetration level of solar power in the southern Nevada system, the impact of solar on system operations needs to be carefully studied from various perspectives. Qualitatively, it is expected that the balancing requirements to compensate for solar power variability will be larger in magnitude; meanwhile, generators providing load following and regulation services will be moved up or down more frequently. One of the most important tasks is to quantitatively evaluate the cycling and movements of conventional generators with solar power at different penetration levels. This study is focused on developing effective methodologies for this goal and providing a basis for evaluating the wear and tear of the conventional generators
Date: July 1, 2011
Creator: Diao, Ruisheng; Lu, Shuai; Etingov, Pavel V.; Ma, Jian; Makarov, Yuri V. & Guo, Xinxin
Object Type: Report
System: The UNT Digital Library
Definitive Alkene Identification Needed for In-Vitro Studies with Ole (Olefin Synthesis) Proteins (open access)

Definitive Alkene Identification Needed for In-Vitro Studies with Ole (Olefin Synthesis) Proteins

None
Date: July 11, 2011
Creator: Beller, Harry; Goh, Ee-Been & Keasling, Jay
Object Type: Article
System: The UNT Digital Library
Direct probe of Mott-Hubbard to charge-transfer insulator transition and electronic structure evolution in transition-metal systems (open access)

Direct probe of Mott-Hubbard to charge-transfer insulator transition and electronic structure evolution in transition-metal systems

We report the most direct experimental verification of Mott-Hubbard and charge-transfer insulators through x-ray emission spectroscopy in transition-metal (TM) fluorides. The p-d hybridization features in the spectra allow a straightforward energy alignment of the anion-2p and metal-3d valence states, which visually shows the difference between the two types of insulators. Furthermore, in parallel with the theoretical Zaanen-Sawatzky-Allen diagram, a complete experimental systematics of the 3d Coulomb interaction and the 2p-3d charge-transfer energy is reported and could serve as a universal experimental trend for other TM systems including oxides.
Date: July 11, 2011
Creator: Olalde-Velasco, P.; Jimenez-Mier, J.; Denlinger, J. D.; Hussain, Z. & Yang, W. L.
Object Type: Article
System: The UNT Digital Library
REACTOR PHYSICS MODELING OF SPENT RESEARCH REACTOR FUEL FOR TECHNICAL NUCLEAR FORENSICS (open access)

REACTOR PHYSICS MODELING OF SPENT RESEARCH REACTOR FUEL FOR TECHNICAL NUCLEAR FORENSICS

Technical nuclear forensics (TNF) refers to the collection, analysis and evaluation of pre- and post-detonation radiological or nuclear materials, devices, and/or debris. TNF is an integral component, complementing traditional forensics and investigative work, to help enable the attribution of discovered radiological or nuclear material. Research is needed to improve the capabilities of TNF. One research area of interest is determining the isotopic signatures of research reactors. Research reactors are a potential source of both radiological and nuclear material. Research reactors are often the least safeguarded type of reactor; they vary greatly in size, fuel type, enrichment, power, and burn-up. Many research reactors are fueled with highly-enriched uranium (HEU), up to {approx}93% {sup 235}U, which could potentially be used as weapons material. All of them have significant amounts of radiological material with which a radioactive dispersal device (RDD) could be built. Therefore, the ability to attribute if material originated from or was produced in a specific research reactor is an important tool in providing for the security of the United States. Currently there are approximately 237 operating research reactors worldwide, another 12 are in temporary shutdown and 224 research reactors are reported as shut down. Little is currently known about the …
Date: July 18, 2011
Creator: Nichols, T.; Beals, D. & Sternat, M.
Object Type: Article
System: The UNT Digital Library