Correlation between structure and electrical transport in ion-irradiated graphene grown on Cu foils (open access)

Correlation between structure and electrical transport in ion-irradiated graphene grown on Cu foils

Graphene grown by chemical vapor deposition and supported on SiO2 and sapphire substrates was studied following controlled introduction of defects induced by 35 keV carbon ion irradiation. Changes in Raman spectra following fluences ranging from 1012 cm-2 to 1015 cm-2 indicate that the structure of graphene evolves from a highly-ordered layer, to a patchwork of disordered domains, to an essentially amorphous film. These structural changes result in a dramatic decrease in the Hall mobility by orders of magnitude while, remarkably, the Hall concentration remains almost unchanged, suggesting that the Fermi level is pinned at a hole concentration near 1x1013 cm-2. A model for scattering by resonant scatterers is in good agreement with mobility measurements up to an ion fluence of 1x1014 cm-2.
Date: November 4, 2010
Creator: Buchowicz, G.; Stone, P. R.; Robinson, J. T.; Cress, C. D.; Beeman, J. W. & Dubon, O. D.
Object Type: Article
System: The UNT Digital Library
A Ferrocene-Based Catecholamide Ligand: the Consequences of Ligand Swivel for Directed Supramolecular Self-Assembly (open access)

A Ferrocene-Based Catecholamide Ligand: the Consequences of Ligand Swivel for Directed Supramolecular Self-Assembly

A ferrocene-based biscatecholamide ligand was prepared and investigated for the formation of metal-ligand supramolecular assemblies with different metals. Reaction with Ge(IV) resulted in the formation of a variety of Ge{sub n}L{sub m} coordination complexes, including [Ge{sub 2}L{sub 3}]{sup 4-} and [Ge{sub 2}L{sub 2}({mu}-OMe){sub 2}]{sup 2-}. The ligand's ability to swivel about the ferrocenyl linker and adopt different conformations accounts for formation of many different Ge{sub n}L{sub m} species. This study demonstrates why conformational ligand rigidity is essential in the rational design and directed self-assembly of supramolecular complexes.
Date: February 4, 2010
Creator: Mugridge, Jeffrey; Fiedler, Dorothea & Raymond, Kenneth
Object Type: Article
System: The UNT Digital Library
Neutron Capture Gamma-Ray Libraries for Nuclear Applications (open access)

Neutron Capture Gamma-Ray Libraries for Nuclear Applications

The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. this can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is …
Date: November 4, 2010
Creator: Sleaford, B. W.; Firestone, R. B.; Summers, N.; Escher, J.; Hurst, A.; Krticka, M. et al.
Object Type: Article
System: The UNT Digital Library
Operations & Maintenance Best Practices - A Guide to Achieving Operational Efficiency (Release 3) (open access)

Operations & Maintenance Best Practices - A Guide to Achieving Operational Efficiency (Release 3)

This guide highlights operations and maintenance programs targeting energy and water efficiency that are estimated to save 5% to 20% on energy bills without a significant capital investment. The purpose of this guide is to provide you, the Operations and Maintenance (O&M)/Energy manager and practitioner, with useful information about O&M management, technologies, energy and water efficiency, and cost-reduction approaches. To make this guide useful and to reflect your needs and concerns, the authors met with O&M and Energy managers via Federal Energy Management Program (FEMP) workshops. In addition, the authors conducted extensive literature searches and contacted numerous vendors and industry experts. The information and case studies that appear in this guide resulted from these activities. It needs to be stated at the outset that this guide is designed to provide information on effective O&M as it applies to systems and equipment typically found at Federal facilities. This guide is not designed to provide the reader with step-by-step procedures for performing O&M on any specific piece of equipment. Rather, this guide first directs the user to the manufacturer's specifications and recommendations. In no way should the recommendations in this guide be used in place of manufacturer's recommendations. The recommendations in this …
Date: August 4, 2010
Creator: Sullivan, Greg; Pugh, Ray; Melendez, Aldo P. & Hunt, W. D.
Object Type: Report
System: The UNT Digital Library
Polarized proton beams in RHIC (open access)

Polarized proton beams in RHIC

The polarized beam for RHIC is produced in the optically-pumped polarized H{sup -} ion source and then accelerated in Linac to 200 MeV for strip-injection to Booster and further accelerated 24.3 GeV in AGS for injection in RHIC. In 2009 Run polarized protons was successfully accelerated to 250 GeV beam energy. The beam polarization of about 60% at 100 GeV beam energy and 36-42% at 250 GeV beam energy was measured with the H-jet and p-Carbon CNI polarimeters. The gluon contribution to the proton spin was studied in collisions of longitudinally polarized proton beams at 100 x 100 GeV. At 250 x 250 GeV an intermediate boson W production with the longitudinally polarized beams was studied for the first time.
Date: October 4, 2010
Creator: Zelenski, A.
Object Type: Article
System: The UNT Digital Library
Novel Sorption Enhanced Reaction Process for Simultaneous Production of CO2 and H2 from Synthesis Gas Produced by Coal Gasification (open access)

Novel Sorption Enhanced Reaction Process for Simultaneous Production of CO2 and H2 from Synthesis Gas Produced by Coal Gasification

The goal of this project is to evaluate the extensive feasibility of a novel concept called Thermal Swing Sorption Enhanced Reaction (TSSER) process to simultaneously produce H{sub 2} and CO{sub 2} as a single unit operation in a sorber-reactor. The successful demonstration of the potential feasibility of the TSSER concept implies that it is worth pursuing further development of the idea. This can be done by more extensive evaluation of the basic sorptive properties of the CO{sub 2} chemisorbents at realistic high pressures and by continuing the experimental and theoretical study of the TSSER process. This will allow us to substantiate the assumptions made during the preliminary design and evaluation of the process and firm up the initial conclusions. The task performed under this project consists of (i) retrofitting an existing single column sorption apparatus for measurement of high pressure CO{sub 2} sorption characteristics, (ii) measurement of high pressure CO{sub 2} chemisorption equilibria, kinetics and sorption-desorption column dynamic characteristics under the conditions of thermal swing operation of the TSSER process, (iii) experimental evaluation of the individual steps of the TSSER process (iv) development of extended mathematical model for simulating cyclic continuous operation of TSSER to aid in process scale-up and …
Date: June 4, 2010
Creator: Sircar, Shivaji; Caram, Hugo S.; Jeong, Kwangkook; Beaver, Michael G.; Ni, Fan & Makebe, Agbor Tabi
Object Type: Report
System: The UNT Digital Library
Accelerating the Payment of PACE Assessments By Mark Zimring and Merrian Fulle (open access)

Accelerating the Payment of PACE Assessments By Mark Zimring and Merrian Fulle

The 'acceleration' of land-secured assessments allows municipalities to declare the entire value (not just the late payments) of a property owner's outstanding balance payable if a default occurs. State laws vary on whether acceleration is required, permitted, or prohibited. Acceleration can be attractive to bond investors because it strips out non-performing assessments, and may avoid delays in debt service payments to investors. The risk that non-acceleration will negatively impact bond investors is a particular issue in states without a process for rapidly resolving defaults. However, acceleration may also increase the risk to mortgage holders, as the full amount of the outstanding assessment becomes due and traditionally has priority over other lien holders. Acceleration also places a greater burden on the property owner.
Date: May 4, 2010
Creator: Zimring, Mark & Fuller, Merrian
Object Type: Report
System: The UNT Digital Library
Images of the Laser Entrance Hole from the Static X-ray Imager at NIF (open access)

Images of the Laser Entrance Hole from the Static X-ray Imager at NIF

The Static X-ray Imager (SXI) at the National Ignition Facility (NIF) is a pinhole camera using a CCD detector to obtain images of hohlraum wall x-ray drive illumination patterns seen through the laser entrance hole (LEH). Carefully chosen filters combined with the CCD response allows recording images in the x-ray range of 3 to 5 keV with 60 {micro}m spatial resolution. The routines used to obtain the apparent size of the backlit LEH, and the location and intensity of beam spots are discussed and compared to predictions. A new soft x-ray channel centered at 870 eV (near the x-ray peak of a 300 eV temperature ignition hohlraum) is discussed.
Date: May 4, 2010
Creator: Schneider, M; Jones, O; Meezan, N; Milovich, J; Town, R; Alvarez, S et al.
Object Type: Article
System: The UNT Digital Library
Self-Correcting HVAC Controls Project Final Report (open access)

Self-Correcting HVAC Controls Project Final Report

This document represents the final project report for the Self-Correcting Heating, Ventilating and Air-Conditioning (HVAC) Controls Project jointly funded by Bonneville Power Administration (BPA) and the U.S. Department of Energy (DOE) Building Technologies Program (BTP). The project, initiated in October 2008, focused on exploratory initial development of self-correcting controls for selected HVAC components in air handlers. This report, along with the companion report documenting the algorithms developed, Self-Correcting HVAC Controls: Algorithms for Sensors and Dampers in Air-Handling Units (Fernandez et al. 2009), document the work performed and results of this project.
Date: January 4, 2010
Creator: Fernandez, Nicholas; Brambley, Michael R.; Katipamula, Srinivas; Cho, Heejin; Goddard, James K. & Dinh, Liem H.
Object Type: Report
System: The UNT Digital Library
Energy Gaps in the Failed High-Tc Superconductor La_1.875Ba_0.125CuO_4 (open access)

Energy Gaps in the Failed High-Tc Superconductor La_1.875Ba_0.125CuO_4

A central issue on high-T{sub c} superconductivity is the nature of the normal-state gap (pseudogap) in the underdoped regime and its relationship with superconductivity. Despite persistent efforts, theoretical ideas for the pseudogap evolve around fluctuating superconductivity, competing order and spectral weight suppression due to many-body effects. Recently, while some experiments in the superconducting state indicate a distinction between the superconducting gap and pseudogap, others in the normal state, either by extrapolation from high-temperature data or directly from La{sub 1.875}Ba{sub 0.125}CuO{sub 4} (LBCO-1/8) at low temperature, suggest the ground-state pseudogap is a single gap of d-wave form. Here we report angle-resolved photoemission (ARPES) data from LBCO-1/8, collected with improved experimental conditions, that reveal the ground-state pseudogap has a pronounced deviation from the simple d-wave form. It contains two distinct components: a d-wave component within an extended region around the node and the other abruptly enhanced close to the antinode, pointing to a dual nature of the pseudogap in this failed high-T{sub c} superconductor which involves a possible precursor pairing energy scale around the node and another of different but unknown origin near the antinode.
Date: May 4, 2010
Creator: He, R.
Object Type: Article
System: The UNT Digital Library
MELT RATE ENHANCEMENT FOR HIGH ALUMINUM HLW (HIGH LEVEL WASTE) GLASS FORMULATION FINAL REPORT 08R1360-1 (open access)

MELT RATE ENHANCEMENT FOR HIGH ALUMINUM HLW (HIGH LEVEL WASTE) GLASS FORMULATION FINAL REPORT 08R1360-1

This report describes the development and testing of new glass formulations for high aluminum waste streams that achieve high waste loadings while maintaining high processing rates. The testing was based on the compositions of Hanford High Level Waste (HLW) with limiting concentrations of aluminum specified by the Office of River Protection (ORP). The testing identified glass formulations that optimize waste loading and waste processing rate while meeting all processing and product quality requirements. The work included preparation and characterization of crucible melts and small scale melt rate screening tests. The results were used to select compositions for subsequent testing in a DuraMelter 100 (DM100) system. These tests were used to determine processing rates for the selected formulations as well as to examine the effects of increased glass processing temperature, and the form of aluminum in the waste simulant. Finally, one of the formulations was selected for large-scale confirmatory testing on the HLW Pilot Melter (DM1200), which is a one third scale prototype of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) HLW melter and off-gas treatment system. This work builds on previous work performed at the Vitreous State Laboratory (VSL) for Department of Energy (DOE) to increase waste loading …
Date: January 4, 2010
Creator: AA, KRUGER; KS, MATLACK; W, KOT; IL, PEGG; I, JOSEPH; T, BARDAKCI et al.
Object Type: Report
System: The UNT Digital Library
DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 5 (MACROBATCH 6) (open access)

DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 5 (MACROBATCH 6)

The Waste Acceptance Product Specifications (WAPS) 1.2 require that ''The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115''. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: …
Date: February 4, 2010
Creator: Bannochie, C.; Bibler, N. & Diprete, D.
Object Type: Report
System: The UNT Digital Library
The Impact of an Oxygen Dopant in an ideal Bi_2Sr_2CaCu_2O_8 delta Crystal (open access)

The Impact of an Oxygen Dopant in an ideal Bi_2Sr_2CaCu_2O_8 delta Crystal

Recent scanning tunneling microscopy studies have shown that local nanoscale pairing inhomogenities are correlated with interstitial oxygen dopants in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}. Combining electrostatic and cluster calculations, in this paper the impact of a dopant on the local Madelung and charge transfer energies, magnetic exchange J, Zhang-Rice mobility, and interactions with the lattice is investigated. It is found that electrostatic modifications locally increases the charge transfer energy and slightly suppresses J. It is further shown that coupling to c-axis phonons is strongly modified near the dopant. The combined effects of electrostatic modifications and coupling to the lattice yield broadened spectral features, reduced charge gap energies, and a sizable local increase of J. This implies a strong local interplay between antiferromagnetism, polarons, and superconducting pairing.
Date: May 4, 2010
Creator: Johnston, S.
Object Type: Article
System: The UNT Digital Library
Stay Rates of Foreign Doctorate Recipients from U.S. Universities, 2007 (open access)

Stay Rates of Foreign Doctorate Recipients from U.S. Universities, 2007

Study of the stay rate in the United States of foreign nationals receiving their S/E doctorates from U.S. universities. This study has estimated stay rates in 2007 for persons receiving a doctorate one, two, five, and ten years previously. The two-year stay rate (for 2005 graduates) recovered from the decline experienced earlier in the decade. The five-year stay rate (for 2002 graduates) is lower; the ten-year stay rate (for 1997 graduates) reached a new high.
Date: January 4, 2010
Creator: Finn, Dr. Michael G.
Object Type: Report
System: The UNT Digital Library
Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities (open access)

Assessment and Mitigation of Electromagnetic Pulse (EMP) Impacts at Short-pulse Laser Facilities

The National Ignition Facility (NIF) will be impacted by electromagnetic pulse (EMP) during normal long-pulse operation, but the largest impacts are expected during short-pulse operation utilizing the Advanced Radiographic Capability (ARC). Without mitigation these impacts could range from data corruption to hardware damage. We describe our EMP measurement systems on Titan and NIF and present some preliminary results and thoughts on mitigation.
Date: February 4, 2010
Creator: Brown, Jr., C G; Bond, E; Clancy, T; Dangi, S; Eder, D C; Ferguson, W et al.
Object Type: Article
System: The UNT Digital Library
Waste Area Group 10, Operable Unit 10-08, Annual Monitoring Status Report for Fiscal Year 2009 (open access)

Waste Area Group 10, Operable Unit 10-08, Annual Monitoring Status Report for Fiscal Year 2009

This report documents the status of Fiscal Year 2009 groundwater monitoring performed in Waste Area Group 10 at the U.S. Department of Energy Idaho National Laboratory Site, as identified in the Groundwater Monitoring and Field Sampling Plan for Operable Unit 10-08. Twelve of the fourteen required wells were sampled, and all ten required intervals from the Westbay wells were sampled. Two wells were not sampled because they were in the process of being converted into multiple-sample-interval Westbay wells by the U.S. Geological Survey. Groundwater samples were analyzed for volatile organic compounds identified on the Contract Laboratory Program target analyte list as well as metals (filtered), anions, and radionuclides (i.e., I-129, tritium, Tc-99, gross alpha, gross beta, and Sr-90). No contaminant exceeded maximum contaminant levels in wells along the southern boundary of the Idaho National Laboratory Site or in guard wells. Iron was above its secondary maximum contaminant level of 300 ug/L in one well. The cause of the elevated iron concentration is uncertain. Lead was detected just below its action level. However, the zinc concentration was also elevated in these wells, and the source of the lead is probably galvanized riser pipe in the wells. Once the galvanized pipe is …
Date: February 4, 2010
Creator: Forsythe, Howard
Object Type: Report
System: The UNT Digital Library
Bogoliubov Angle, Particle-Hole Mixture and Angular Resolved Photoemission Spectroscopy in Superconductors (open access)

Bogoliubov Angle, Particle-Hole Mixture and Angular Resolved Photoemission Spectroscopy in Superconductors

Superconducting excitations - Bogoliubov quasiparticles - are the quantum mechanical mixture of negatively charged electron (-e) and positively charged hole (+e). We propose a new observable for Angular Resolved Photoemission Spectroscopy (ARPES) studies that is the manifestation of the particle-hole entanglement of the superconducting quasiparticles. We call this observable a Bogoliubov angle. This angle measures the relative weight of particle and hole amplitude in the superconducting (Bogoliubov) quasiparticle. We show how this quantity can be measured by comparing the ratio of spectral intensities at positive and negative energies.
Date: May 4, 2010
Creator: Balatsky, A.
Object Type: Article
System: The UNT Digital Library
DISTRIBUTION AND RANGE OF RADIONUCLIDE SORPTIOIN COEFFICIENTS IN A SAVANNAH RIVER SITE SUBSURFACE: STOCHASTIC MODELING CONSIDERATIONS - 10259 (open access)

DISTRIBUTION AND RANGE OF RADIONUCLIDE SORPTIOIN COEFFICIENTS IN A SAVANNAH RIVER SITE SUBSURFACE: STOCHASTIC MODELING CONSIDERATIONS - 10259

The uncertainty associated with the sorption coefficient, or K{sub d} value, is one of the key uncertainties in estimating risk associated with burying low-level nuclear waste in the subsurface. The objective of this study was to measure >648 K{sub d} values and provide a measure of the range and distribution (normal or log-normal) of radionuclide K{sub d} values appropriate for the E-Area disposal site, within the Savannah River Site, near Aiken South Carolina. The 95% confidence level for the mean K{sub d} was twice the mean in the Aquifer Zone (18-30.5 m depth), equal to the mean for the Upper Vadose Zone (3.3-10 m depth), and half the mean for the Lower Vadose Zone (3.3-18 m depth). The distribution of K{sub d} values was log normal in the Upper Vadose Zone and Aquifer Zone, and normal in the Lower Vadose Zone. To our knowledge, this is the first report of natural radionuclide K{sub d} variability in the literature. Using ranges and distribution coefficients that are specific to the hydrostratigraphic unit improved model accuracy and reduced model uncertainty. Unfortunately, extension of these conclusions to other sites is likely not appropriate given that each site has its own sources of hydrogeological variability. …
Date: January 4, 2010
Creator: Kaplan, D.
Object Type: Article
System: The UNT Digital Library
EMSL Quarterly Highlights Report: 1st Quarter, Fiscal Year 2010 (open access)

EMSL Quarterly Highlights Report: 1st Quarter, Fiscal Year 2010

This report outlines the science, awards and honors, and publications that resulted during the first quarter of Fiscal Year 2010 at EMSL.
Date: February 4, 2010
Creator: Showalter, Mary Ann; Kathmann, Loel E.; Manke, Kristin L.; Wiley, Julie G. & Reed, Jennifer R.
Object Type: Report
System: The UNT Digital Library
Momentum Transfer by Laser Ablation of Irregularly Shaped Space Debris (open access)

Momentum Transfer by Laser Ablation of Irregularly Shaped Space Debris

Proposals for ground-based laser remediation of space debris rely on the creation of appropriately directed ablation-driven impulses to either divert the fragment or drive it into an orbit with a perigee allowing atmospheric capture. For a spherical fragment, the ablation impulse is a function of the orbital parameters and the laser engagement angle. If, however, the target is irregularly shaped and arbitrarily oriented, new impulse effects come into play. Here we present an analysis of some of these effects.
Date: February 4, 2010
Creator: Liedahl, D A; Libby, S B & Rubenchik, A
Object Type: Article
System: The UNT Digital Library
Discrete Sampling Test Plan for the 200-BP-5 Operable Unit (open access)

Discrete Sampling Test Plan for the 200-BP-5 Operable Unit

The Discrete Groundwater Sampling Project is conducted by the Pacific Northwest National Laboratory (PNNL) on behalf of CH2M HILL Plateau Remediation Company. The project is focused on delivering groundwater samples from proscribed horizons within select groundwater wells residing in the 200-BP-5 Operable Unit (200-BP-5 OU) on the Hanford Site. This document provides the scope, schedule, methodology, and other details of the PNNL discrete sampling effort.
Date: February 4, 2010
Creator: Sweeney, Mark D.
Object Type: Report
System: The UNT Digital Library
Remediation of Uranium in the Hanford Vadose Zone Using Gas-Transported Reactants: Laboratory Scale Experiments in Support of the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau (open access)

Remediation of Uranium in the Hanford Vadose Zone Using Gas-Transported Reactants: Laboratory Scale Experiments in Support of the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau

This laboratory-scale investigation is focused on decreasing mobility of uranium in subsurface contaminated sediments in the vadose zone by in situ geochemical manipulation at low water content. This geochemical manipulation of the sediment surface phases included reduction, pH change (acidic and alkaline), and additions of chemicals (phosphate, ferric iron) to form specific precipitates. Reactants were advected into 1-D columns packed with Hanford 200 area U-contaminated sediment as a reactive gas (for CO2, NH3, H2S, SO2), with a 0.1% water content mist (for NaOH, Fe(III), HCl, PO4) and with a 1% water content foam (for PO4). Uranium is present in the sediment in multiple phases that include (in decreasing mobility): aqueous U(VI) complexes, adsorbed U, reduced U(IV) precipitates, rind-carbonates, total carbonates, oxides, silicates, phosphates, and in vanadate minerals. Geochemical changes were evaluated in the ability to change the mixture of surface U phases to less mobile forms, as defined by a series of liquid extractions that dissolve progressively less soluble phases. Although liquid extractions provide some useful information as to the generalized uranium surface phases (and are considered operational definitions of extracted phases), positive identification (by x-ray diffraction, electron microprobe, other techniques) was also used to positively identify U phases and …
Date: January 4, 2010
Creator: Szecsody, James E.; Truex, Michael J.; Zhong, Lirong; Williams, Mark D.; Resch, Charles T. & McKinley, James P.
Object Type: Report
System: The UNT Digital Library
HIGH ALUMINUM HLW (HIGH LEVEL WASTE ) GLASSES FOR HANFORDS WTP (WASTE TREATMENT PROJECT) (open access)

HIGH ALUMINUM HLW (HIGH LEVEL WASTE ) GLASSES FOR HANFORDS WTP (WASTE TREATMENT PROJECT)

This paper presents the results of glass formulation development and melter testing to identify high waste loading glasses to treat high-Al high level waste (HLW) at Hanford. Previous glass formulations developed for this HLW had high waste loadings but their processing rates were lower that desired. The present work was aimed at improving the glass processing rate while maintaining high waste loadings. Glass formulations were designed, prepared at crucible-scale and characterized to determine their properties relevant to processing and product quality. Glass formulations that met these requirements were screened for melt rates using small-scale tests. The small-scale melt rate screening included vertical gradient furnace (VGF) and direct feed consumption (DFC) melter tests. Based on the results of these tests, modified glass formulations were developed and selected for larger scale melter tests to determine their processing rate. Melter tests were conducted on the DuraMelter 100 (DMIOO) with a melt surface area of 0.11 m{sup 2} and the DuraMelter 1200 (DMI200) HLW Pilot Melter with a melt surface area of 1.2 m{sup 2}. The newly developed glass formulations had waste loadings as high as 50 wt%, with corresponding Al{sub 2}O{sub 3} concentration in the glass of 26.63 wt%. The new glass formulations …
Date: January 4, 2010
Creator: AA, KRUGER; BW, BOWAN; I, JOSEPH; H, GAN; WK, KOT; KS, MATLACK et al.
Object Type: Article
System: The UNT Digital Library
MULTI-KEV X-RAY YIELDS FROM HIGH-Z GAS TARGETS FIELDED AT OMEGA (open access)

MULTI-KEV X-RAY YIELDS FROM HIGH-Z GAS TARGETS FIELDED AT OMEGA

The authors report on modeling of x-ray yield from gas-filled targets shot at the OMEGA laser facility. The OMEGA targets were 1.8 mm long, 1.95 mm in diameter Be cans filled with either a 50:50 Ar:Xe mixture, pure Ar, pure Kr or pure Xe at {approx} 1 atm. The OMEGA experiments heated the gas with 20 kJ of 3{omega} ({approx} 350 nm) laser energy delivered in a 1 ns square pulse. the emitted x-ray flux was monitored with the x-ray diode based DANTE instruments in the sub-keV range. Two-dimensional x-ray images (for energies 3-5 keV) of the targets were recorded with gated x-ray detectors. The x-ray spectra were recorded with the HENWAY crystal spectrometer at OMEGA. Predictions are 2D r-z cylindrical with DCA NLTE atomic physics. Models generally: (1) underpredict the Xe L-shell yields; (2) overpredict the Ar K-shell yields; (3) correctly predict the Xe thermal yields; and (4) greatly underpredict the Ar thermal yields. However, there are spreads within the data, e.g. the DMX Ar K-shell yields are correctly predicted. The predicted thermal yields show strong angular dependence.
Date: November 4, 2010
Creator: Kane, J O; Fournier, K B; May, M J; Colvin, J D; Thomas, C A; Marrs, R E et al.
Object Type: Article
System: The UNT Digital Library