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IRON-PHOSPHATE GLASS FOR IMMOBILIZATION OF RADIOACTIVE TECHNETIUM
Technetium-99 (Tc-99) can bring a serious environmental threat because of its high fission yield, long half-life, and high solubility and mobility in the ground water. The present work investigated the immobilization of Tc-99 (surrogated by Re) by heat-treating mixtures of an iron-phosphate glass with 1.5 to 6 wt.% KReO{sub 4} at {approx}1000 C. The Re retention in the glass was as high as {approx}1.2 wt. % while the loss of Re by evaporation during melting was {approx}50%. Re was uniformly distributed within the glass. The normalized Re release by the 7-day Product Consistency Test was {approx}0.39 g/m{sup 2}, comparable with that in phosphate-bonded ceramics and borosilicate glasses. These results suggest that iron-phosphate glass can provide a good matrix for immobilizing Tc-99.
Date:
March 19, 2012
Creator:
AA, KRUGER; PR, HRMA; K, XU; J, CHOI; W, UM & J, HEO
Object Type:
Article
System:
The UNT Digital Library
STATUS OF THE DEVELOPMENT OF IN-TANK/AT-TANK SEPARATIONS TECHNOLOGIES FOR FOR HIGH-LEVEL WASTE PROCESSING FOR THE U.S. DEPARTMENT OF ENERGY
Within the U.S. Department of Energy's (DOE) Office of Technology Innovation and Development, the Office of Waste Processing manages a research and development program related to the treatment and disposition of radioactive waste. At the Savannah River (South Carolina) and Hanford (Washington) Sites, approximately 90 million gallons of waste are distributed among 226 storage tanks (grouped or collocated in 'tank farms'). This waste may be considered to contain mixed and stratified high activity and low activity constituent waste liquids, salts and sludges that are collectively managed as high level waste (HLW). A large majority of these wastes and associated facilities are unique to the DOE, meaning many of the programs to treat these materials are 'first-of-a-kind' and unprecedented in scope and complexity. As a result, the technologies required to disposition these wastes must be developed from basic principles, or require significant re-engineering to adapt to DOE's specific applications. Of particular interest recently, the development of In-tank or At-Tank separation processes have the potential to treat waste with high returns on financial investment. The primary objective associated with In-Tank or At-Tank separation processes is to accelerate waste processing. Insertion of the technologies will (1) maximize available tank space to efficiently support …
Date:
September 19, 2011
Creator:
Aaron, G. & Wilmarth, B.
Object Type:
Article
System:
The UNT Digital Library
A Change in the Optical Polarization Associated with a Gamma-Ray Flare in the Blazar 3C 279
It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight. The size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. Here we report the coincidence of a gamma ({gamma})-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and {gamma}-ray emission regions and indicates a highly ordered jet magnetic field. The results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 10{sup 5} gravitational radii.
Date:
August 19, 2011
Creator:
Abdo, A. A.
Object Type:
Article
System:
The UNT Digital Library
Fermi-LAT Discovery of GeV Gamma-ray Emission from the Young Supernova Remnant Cassiopeia A
We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2{sigma} above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation - Cassiopeia A. The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as W{sub CR} {approx_equal} (1-4) x 10{sup 49} erg thanks to the well-known density in the remnant assuming that the observed gamma-ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B {ge} 0.1 mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.
Date:
August 19, 2011
Creator:
Abdo, A. A.
Object Type:
Article
System:
The UNT Digital Library
The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called 'extra-galactic' diffuse {gamma}-ray emission (EGB). This component of the diffuse {gamma}-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modelling of the bright foreground diffuse Galactic {gamma}-ray emission (DGE), the detected LAT sources and the solar {gamma}-ray emission. We find the spectrum of the EGB is consistent with a power law with differential spectral index {gamma} = 2.41 {+-} 0.05 and intensity, I(> 100 MeV) = (1.03 {+-} 0.17) x 10{sup -5} cm{sup -2} s{sup -1} sr{sup -1}, where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.
Date:
August 19, 2011
Creator:
Abdo, A. A.
Object Type:
Article
System:
The UNT Digital Library
Lebanon: Background and U.S. Relations
This report provides an overview of Lebanese politics, recent events in Lebanon, and current issues in U.S.-Lebanon relations.
Date:
January 19, 2011
Creator:
Addis, Casey L.
Object Type:
Report
System:
The UNT Digital Library
U.S. Security Assistance to Lebanon
This report discusses key issues facing U.S. policy makers and members of Congress when considering U.S. security assistance in the context of U.S. policy toward Lebanon. These key issues include assessing the effectiveness of U.S. assistance programs, assessing overall U.S. policy toward Lebanon, and managing relations with other external actors.
Date:
January 19, 2011
Creator:
Addis, Casey L.
Object Type:
Report
System:
The UNT Digital Library
Design Methodology and Consideratios for NOVA 53 MHZ RF Cavities
The NO?A Experiment will construct a detector optimized for electron neutrino detection in the existing Neutrino at Main Injector (NuMI) beamline. This beamline is capable of operating at 400 kW of primary beam power and the upgrade will allow up to 700 kW. The cavities will operate at 53 MHz and three of them will be installed in the Recycler beamline. Thermal stability of the cavities is crucial since this affects the tuning. Results of finite element thermal and structural analysis involving the copper RF cavity will be presented.
Date:
May 19, 2010
Creator:
Ader, C. & Wildman, D.W.
Object Type:
Article
System:
The UNT Digital Library
Tank 26F-2F Evaporator Study
Tank 26F supernate sample was sent by Savannah River Remediation to Savannah River National Laboratory for evaporation test to help understand the underlying cause of the recent gravity drain line (GDL) pluggage during operation of the 2F Evaporator system. The supernate sample was characterized prior to the evaporation test. The evaporation test involved boiling the supernate in an open beaker until the density of the concentrate (evaporation product) was between 1.4 to 1.5 g/mL. It was followed by filtering and washing of the precipitated solids with deionized water. The concentrate supernate (or concentrate filtrate), the damp unwashed precipitated solids, and the wash filtrates were characterized. All the precipitated solids dissolved during water washing. A semi-quantitative X-ray diffraction (XRD) analysis on the unwashed precipitated solids revealed their composition. All the compounds with the exception of silica (silicon oxide) are known to be readily soluble in water. Hence, their dissolution during water washing is not unexpected. Even though silica is a sparingly water-soluble compound, its dissolution is also not surprising. This stems from its small fraction in the solids as a whole and also its relative freshness. Assuming similar supernate characteristics, flushing the GDL with water (preferably warm) should facilitate dissolution and …
Date:
December 19, 2012
Creator:
Adu-Wusu, K.
Object Type:
Report
System:
The UNT Digital Library
CDMSlite: A Search for Low-Mass WIMPs using Voltage-Assisted Calorimetric Ionization Detection in the SuperCDMS Experiment
None
Date:
February 19, 2014
Creator:
Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Thakur, R. Basu; Bauer, D. A. et al.
Object Type:
Article
System:
The UNT Digital Library
Fresh Water Generation from Aquifer-Pressured Carbon Storage
Can we use the pressure associated with sequestration to make brine into fresh water? This project is establishing the potential for using brine pressurized by Carbon Capture and Storage (CCS) operations in saline formations as the feedstock for desalination and water treatment technologies including reverse osmosis (RO) and nanofiltration (NF). Possible products are: Drinking water, Cooling water, and Extra aquifer space for CO{sub 2} storage. The conclusions are: (1) Many saline formation waters appear to be amenable to largely conventional RO treatment; (2) Thermodynamic modeling indicates that osmotic pressure is more limiting on water recovery than mineral scaling; (3) The use of thermodynamic modeling with Pitzer's equations (or Extended UNIQUAC) allows accurate estimation of osmotic pressure limits; (4) A general categorization of treatment feasibility is based on TDS has been proposed, in which brines with 10,000-85,000 mg/L are the most attractive targets; (5) Brines in this TDS range appear to be abundant (geographically and with depth) and could be targeted in planning future CCS operations (including site selection and choice of injection formation); and (6) The estimated cost of treating waters in the 10,000-85,000 mg/L TDS range is about half that for conventional seawater desalination, due to the anticipated pressure …
Date:
February 19, 2010
Creator:
Aines, R. D.; Wolery, T. J.; Bourcier, W. L.; Wolfe, T. & Haussmann, C.
Object Type:
Article
System:
The UNT Digital Library
Constraints on Dark Matter Models From a Fermi LAT Search for High-Energy Cosmic-Ray Electrons from the Sun
None
Date:
March 19, 2013
Creator:
Ajello, M.; Atwood, W. B.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R. et al.
Object Type:
Article
System:
The UNT Digital Library
A Dual Channel X-ray Spectrometer for Fast Ignition Research
A new Dual Channel Highly Ordered Pyrolytic Graphite (DC-HOPG) x-ray spectrometer was developed to study laser-generated electron beam transport. The instrument uses a pair of graphite crystals and has the advantage of simultaneously detecting self emission from low-Z materials in first diffraction order and high-Z materials in second order. The emissions from the target are detected using a pair of parallel imaging plates positioned in a such way that the noise from background is minimized and the mosaic focusing is achieved. Initial tests of the diagnostic on Titan laser (I {approx} 10{sup 20} W/cm{sup 2}, {tau} = 0.7 ps) show excellent signal-to-noise ratio (SNR) > 1000 for the low energy channel and SNR > 400 for the high energy channel.
Date:
April 19, 2010
Creator:
Akli, K. U.; Patel, P. K.; Van Maren, R.; Stephens, R. B.; Key, M. H.; Higginson, D. P. et al.
Object Type:
Article
System:
The UNT Digital Library
A Solid-State Nanosecond Beam Kicker Modulator Based on the DSRD Switch
A fast solid-state beam kicker modulator is under development at the SLAC National Accelerator Laboratory. The program goal is to develop a modulator that will deliver 4 ns, {+-}5 kV pulses to the ATF2 damping ring beam extraction kicker. The kicker is a 50 {Omega}, bipolar strip line, 60 cm long, fed at the downstream end and terminated at the upstream end. The bunch spacing in the ring is 5.6 ns, bunches are removed from the back end of the train, and there is a gap of 103.6 ns before the next train. The modulator design is based on an opening switch topology that uses Drift Step Recovery Diodes as the opening switches. The design and results of the modulator development are discussed. There are many applications that benefit from very fast high power switching. However, at MW power levels and nanosecond time scales, solid state options are limited. One option, the Drift Step Recovery Diode (DSRD) has been demonstrated as capable of blocking thousands of volts and switching in nanosecond to sub-nanosecond ranges. When used as an opening switch, the DSRD exhibits a very fast turn off transient. The process is described in detail by its pioneers in [5,6]. …
Date:
August 19, 2011
Creator:
Akre, R.; Benwell, A.; Burkhart, C.; Krasnykh, A.; Tang, T. & Kardo-Sysoev, A.
Object Type:
Article
System:
The UNT Digital Library
The 2010 Oil Spill: MMS/BOEMRE and NEPA
This report reviews the environmental procedures required following the explosion of an oil well on a tract leased by BP from the federal government.
Date:
August 19, 2010
Creator:
Alexander, Kristina
Object Type:
Report
System:
The UNT Digital Library
The Gray Wolf and the Endangered Species Act (ESA): A Brief Legal History
This report provides a brief history of the laws, regulations, and lawsuits related to the wolf's protected status. Fuller analyses of the concepts discussed in this report can be found in the companion report.
Date:
January 19, 2012
Creator:
Alexander, Kristina
Object Type:
Report
System:
The UNT Digital Library
A Review of X-ray Diagnostic Calibrations in the 2 to 100 keV Region Using the High Energy X-ray Calibration Facility (HEX)
The precise and accurate measurement of X-rays in the 2 keV to 100 keV region is crucial to the understanding of HED plasmas and warm dense matter in general. With the emergence of inertially confined plasma facilities as the premier platforms for ICF, laboratory astrophysics, and national security related plasma experiments, the need to calibrate diagnostics in the high energy X-ray regime has grown. At National Security Technologies High Energy X-ray Calibration Facility (HEX) in Livermore, California, X-ray imagers, filter-fluorescer spectrometers, crystal spectrometers, image plates, and nuclear diagnostics are calibrated. The HEX can provide measurements of atomic line radiation, X-ray flux (accuracy within 10%), and X-ray energy (accuracy within 1%). The HEX source is comprised of a commercial 160 kV X-ray tube, a fluorescer wheel, a filter wheel, and a lead encasement. The X-ray tube produces a Tungsten bremsstrahlung spectrum which causes a foil to fluoresce line radiation. To minimize bremsstrahlung in the radiation for calibration we also provide various foils as filters. For experimental purposes, a vacuum box capable of 10{sup -7} Torr, as well as HPGe and CdTe radiation detectors, are provided on an optical table. Most geometries and arrangements can be changed to meet experimental needs.
Date:
May 19, 2010
Creator:
Ali, Zaheer; Pond, T.; Buckles, R. A.; Maddox, B. R.; Chen, C. D.; DeWald, E. L. et al.
Object Type:
Article
System:
The UNT Digital Library
Design and Implementation of a Metadata-rich File System
Despite continual improvements in the performance and reliability of large scale file systems, the management of user-defined file system metadata has changed little in the past decade. The mismatch between the size and complexity of large scale data stores and their ability to organize and query their metadata has led to a de facto standard in which raw data is stored in traditional file systems, while related, application-specific metadata is stored in relational databases. This separation of data and semantic metadata requires considerable effort to maintain consistency and can result in complex, slow, and inflexible system operation. To address these problems, we have developed the Quasar File System (QFS), a metadata-rich file system in which files, user-defined attributes, and file relationships are all first class objects. In contrast to hierarchical file systems and relational databases, QFS defines a graph data model composed of files and their relationships. QFS incorporates Quasar, an XPATH-extended query language for searching the file system. Results from our QFS prototype show the effectiveness of this approach. Compared to the de facto standard, the QFS prototype shows superior ingest performance and comparable query performance on user metadata-intensive operations and superior performance on normal file metadata operations.
Date:
January 19, 2010
Creator:
Ames, S; Gokhale, M B & Maltzahn, C
Object Type:
Report
System:
The UNT Digital Library
The Northeast Home Heating Oil Reserve and the National Oilheat Research Alliance
This report discusses the price of home heating oil in the Northeast. The Northeast demand for home heating oil has declined by 47% since 2000, from nearly 7 billion gallons to 3.6 billion gallons in 2011. The report provides detailed information regarding northeast home heating oil reserve and national Oilheat Research Alliance.
Date:
September 19, 2013
Creator:
Andrews, Anthony
Object Type:
Report
System:
The UNT Digital Library
Results of the Excreta Bioassay Quality Control Program for April 1, 2009 through March 31, 2010
A total of 58 urine samples and 10 fecal samples were submitted during the report period (April 1, 2009 through March 31, 2010) to General Engineering Laboratories, South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for Sr, 238Pu, 239Pu, 241Am, 243Am 235U, 238U, elemental uranium and fecal analyses for 241Am, 238Pu and 239Pu were tested this year as well as four tissue samples for 238Pu, 239Pu, 241Am and 241Pu. The number of QC urine samples submitted during the report period represented 1.3% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 33% of the analyses processed by GEL during the third year of this contract were quality control samples. GEL tested the performance of 21 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty (Table 4).
Date:
July 19, 2012
Creator:
Antonio, Cheryl L.
Object Type:
Report
System:
The UNT Digital Library
Results of The Excreta Bioassay Quality Control Program For April 1, 2010 Through March 31, 2011
A total of 76 urine samples and 10 spiked fecal samples were submitted during the report period (April 1, 2010 through March 31, 2011) to GEL Laboratories, LLC in South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for 14C, Sr, for 238Pu, 239Pu, 241Am, 243Am, 235U, 238U, 238U-mass and fecal analyses for 241Am, 238Pu and 239Pu were tested this year. The number of QC urine samples submitted during the report period represented 1.1% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 31% of the analyses processed by GEL during the first year of contract 112512 were quality control samples. GEL tested the performance of 23 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty except the slightly elevated relative bias for 243,244Cm (Table 4).
Date:
July 19, 2012
Creator:
Antonio, Cheryl L.
Object Type:
Report
System:
The UNT Digital Library
Presentations by MIIS-LLNL Safeguards Policy Interns
None
Date:
August 19, 2013
Creator:
Anzelon, G. A.; Davydov, J. S.; Park, K. K.; McCarthy, K. T.; Kuwata, Y. A. & Wilbourne, J. L.
Object Type:
Report
System:
The UNT Digital Library
The European Parliament
This report mainly discusses The European Parliament which is a key institution of 28 member European Union. The role of the European Parliament in the legislative has expanded steadily over time as the scope of EU policy has grown.
Date:
May 19, 2014
Creator:
Archick, Kristin
Object Type:
Report
System:
The UNT Digital Library
The European Union: Questions and Answers
This report serves as a primer on the European Union and provides a brief description of U.S.-EU relations that may be of interest in the 114th Congress.
Date:
January 19, 2016
Creator:
Archick, Kristin
Object Type:
Report
System:
The UNT Digital Library