Dynamic Data-Driven Event Reconstruction for Atmospheric Releases (open access)

Dynamic Data-Driven Event Reconstruction for Atmospheric Releases

Accidental or terrorist releases of hazardous materials into the atmosphere can impact large populations and cause significant loss of life or property damage. Plume predictions have been shown to be extremely valuable in guiding an effective and timely response. The two greatest sources of uncertainty in the prediction of the consequences of hazardous atmospheric releases result from poorly characterized source terms and lack of knowledge about the state of the atmosphere as reflected in the available meteorological data. We have developed a new event reconstruction methodology that provides probabilistic source term estimates from field measurement data for both accidental and clandestine releases. Accurate plume dispersion prediction requires the following questions to be answered: What was released? When was it released? How much material was released? Where was it released? We have developed a dynamic-data-driven event reconstruction capability that couples data and predictive methods through Bayesian inference to obtain a solution to this inverse problem. The solution consists of a probability distribution of unknown source term parameters. For consequence assessment, we then use this probability distribution to construct a 'composite' forward plume prediction that accounts for the uncertainties in the source term. Since in most cases of practical significance it is …
Date: March 29, 2007
Creator: Mirin, A. A. & Kosovic, B.
Object Type: Report
System: The UNT Digital Library
Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site (open access)

Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site

None
Date: May 29, 2007
Creator: Zavarin, M.; Roberts, S. K.; Johnson, M. R.; Hu, Q.; Powell, B. A.; Zhao, P. et al.
Object Type: Report
System: The UNT Digital Library
Improved Optical Quality for Ti:Sapphire using MRF (open access)

Improved Optical Quality for Ti:Sapphire using MRF

None
Date: June 29, 2007
Creator: Schaffers, K. I.; Barty, C. P.; Bayramian, A. J.; Caird, J. A.; Davis, P. J.; Ebbers, C. A. et al.
Object Type: Article
System: The UNT Digital Library
Deviation of Nuclear Radii from a Smooth A Dependence for Neutron Data (open access)

Deviation of Nuclear Radii from a Smooth A Dependence for Neutron Data

None
Date: May 29, 2007
Creator: Dietrich, F. S.; Anderson, J. D.; Bauer, R. W.; Girod, M.; Gogny, D.; Grimes, S. M. et al.
Object Type: Article
System: The UNT Digital Library
High Energy Ion Energy Depletion Model in HYDRA (open access)

High Energy Ion Energy Depletion Model in HYDRA

None
Date: June 29, 2007
Creator: Kerbel, G & Prasad, M
Object Type: Report
System: The UNT Digital Library
Characterization of the Structure of Cation-DopedBacteriogenic Uranium Oxides using X-Ray Diffraction (open access)

Characterization of the Structure of Cation-DopedBacteriogenic Uranium Oxides using X-Ray Diffraction

Remediation of uranium contamination in subsurface groundwater has become imperative as previous research and manufacturing involving radionuclides has led to contamination of groundwater sources. A possible in situ solution for sequestration of uranium is a bacterial process in which Shewanella oneidensis MR-1 reduces the soluble (and thus mobile) U(VI) oxidation state into the less mobile UO{sub 2} crystalline phase. However, the long term stability of the UO2 compound must be studied as oxidative conditions could return it back into the U(VI) state. Incorporation of other cations into the structure during manufacture of the UO{sub 2} could alter the dissolution behavior. A wide angle x-ray scattering (WAXS) experiment was performed to determine whether or not calcium, manganese, and magnesium are incorporated into this structure. If so, the substituted atoms would cause a contraction or expansion in the lattice because of their differing size, causing the lattice constant to be altered. After several stages of data reduction, the WAXS diffraction peaks were fit using the Le Bail fit method in order to determine the lattice constant. Initial results suggest that there may be incorporation of manganese into the UO{sub 2} structure due to a .03 Angstrom decrease in lattice constant, but more …
Date: August 29, 2007
Creator: Stahlman, Jonathan M. & /SLAC, /Carnegie Mellon U.
Object Type: Report
System: The UNT Digital Library
Multiscale Modeling of Polymeric Materials (open access)

Multiscale Modeling of Polymeric Materials

None
Date: May 29, 2007
Creator: Maranas, Janna K.
Object Type: Report
System: The UNT Digital Library
Multi-Petabyte Image Data Management Systems (open access)

Multi-Petabyte Image Data Management Systems

This research effort is directed to determine the methods and computational infrastructure needed to save, browse, and analyze multiple petabyte databases. The data set to be generated by the Large Synoptic Survey Telescope is used as a template for this research.
Date: January 29, 2007
Creator: Dossa, D D
Object Type: Report
System: The UNT Digital Library
Final Scientific/Technical Report (open access)

Final Scientific/Technical Report

Boeing Phantom Works and its team originally proposed a three-year Phase III SPI project to develop a 30-kWh flywheel with a 100 kW power capability as a power risk management system (RMS) for power users and providers. The chief objectives for the Risk Management System Flywheel were to (1) demonstrate its ability to protect a critical load such as a small data center from swings in power availability, cost, and power factor and (2) show that the RMS flywheel can perform these functions with reduced noise, emissions, and operating costs when compared with non-HTS competitors including batteries, diesel generators, and microturbines.
Date: June 29, 2007
Creator: Strasik, Dr. Michael
Object Type: Report
System: The UNT Digital Library
Characterization of Niobium Oxide Films Deposited by High Target Utilization Sputter Sources (open access)

Characterization of Niobium Oxide Films Deposited by High Target Utilization Sputter Sources

High quality, refractory metal, oxide coatings are required in a variety of applications such as laser optics, micro-electronic insulating layers, nano-device structures, electro-optic multilayers, sensors and corrosion barriers. A common oxide deposition technique is reactive sputtering because the kinetic mechanism vaporizes almost any solid material in vacuum. Also, the sputtered molecules have higher energies than those generated from thermal evaporation, and so the condensates are smoother and denser than those from thermally-evaporated films. In the typical sputtering system, target erosion is a factor that drives machine availability. In some situations such as nano-layered capacitors, where the device's performance characteristics depends on thick layers, target life becomes a limiting factor on the maximizing device functionality. The keen interest to increase target utilization in sputtering has been addressed in a variety of ways such as target geometry, rotating magnets, and/or shaped magnet arrays. Also, a recent sputtering system has been developed that generates a high density plasma, directs the plasma beam towards the target in a uniform fashion, and erodes the target in a uniform fashion. The purpose of this paper is to characterize and compare niobia films deposited by two types of high target utilization sputtering sources, a rotating magnetron and …
Date: January 29, 2007
Creator: Chow, R; Ellis, A D; Loomis, G E & Rana, S I
Object Type: Article
System: The UNT Digital Library
TAILORING INORGANIC SORBENTS FOR SRS STRONTIUM AND ACTINIDE SEPARATIONS: OPTIMIZED MONOSODIUM TITANATE PHASE II FINAL REPORT (open access)

TAILORING INORGANIC SORBENTS FOR SRS STRONTIUM AND ACTINIDE SEPARATIONS: OPTIMIZED MONOSODIUM TITANATE PHASE II FINAL REPORT

This document provides a final report of Phase II testing activities for the development of a modified monosodium titanate (MST) that exhibits improved strontium and actinide removal characteristics compared to the baseline MST material. The activities included determining the key synthesis conditions for preparation of the modified MST, preparation of the modified MST at a larger scale by a commercial vendor, demonstration of the strontium and actinide removal characteristics with actual tank waste supernate and measurement of filtration characteristics. Key findings and conclusions include the following. Testing evaluated three synthetic methods and eleven process parameters for the optimum synthesis conditions for the preparation on an improved form of MST. We selected the post synthesis method (Method 3) for continued development based on overall sorbate removal performance. We successfully prepared three batches of the modified MST using Method 3 procedure at a 25-gram scale. The laboratory prepared modified MST exhibited increased sorption kinetics with simulated and actual waste solutions and similar filtration characteristics to the baseline MST. Characterization of the modified MST indicated that the post synthesis treatment did not significantly alter the particle size distribution, but did significantly increase the surface area and porosity compared to the original MST. Testing …
Date: June 29, 2007
Creator: Hobbs, D; Thomas Peters, T; Michael Poirier, M; Mark Barnes, M; Major Thompson, M & Samuel Fink, S
Object Type: Report
System: The UNT Digital Library
2006 Iron-Sulfur Enzymes (June 11-16, 2006) (open access)

2006 Iron-Sulfur Enzymes (June 11-16, 2006)

This is a Final Progress report of Gordon research conference on 2006 Iron-Sulfur Enzymes with the conference agenda.
Date: May 29, 2007
Creator: Gray, Stephen Cramer Nancy Ryan
Object Type: Article
System: The UNT Digital Library
PLUTONIUM FEED IMPURITY TESTING IN A LANTHANIDE BOROSILICATE (LABS) GLASS (open access)

PLUTONIUM FEED IMPURITY TESTING IN A LANTHANIDE BOROSILICATE (LABS) GLASS

A vitrification technology utilizing a lanthanide borosilicate (LaBS) glass is a viable option for dispositioning excess weapons-useable plutonium that is not suitable for processing into mixed oxide (MOX) fuel. A significant effort to develop a glass formulation and vitrification process to immobilize plutonium was completed in the mid-1990s. The LaBS glass formulation was found to be capable of immobilizing in excess of 10 wt % Pu and to be tolerant of a range of impurities. A more detailed study is now needed to quantify the ability of the glass to accommodate the anticipated impurities associated with the Pu feeds now slated for disposition. The database of Pu feeds was reviewed to identify impurity species and concentration ranges for these impurities. Based on this review, a statistically designed test matrix of glass compositions was developed to evaluate the ability of the LaBS glass to accommodate the impurities. Sixty surrogate LaBS glass compositions were prepared in accordance with the statistically designed test matrix. The heterogeneity (e.g. degree of crystallinity) and durability (as measured by the Product Consistency Test - Method A (PCT-A)) of the glasses were used to assess the effects of impurities on glass quality.
Date: August 29, 2007
Creator: Marra, J; Kevin Fox, K; Elizabeth Hoffman, E; Tommy Edwards, T & Charles Crawford, C
Object Type: Article
System: The UNT Digital Library
Long-term X-ray Variability of NGC 4945 (open access)

Long-term X-ray Variability of NGC 4945

Though short-term X-ray variability has been studied for the active galaxy NGC 4945, long-term studies promise to contribute to our understanding of the processes involved in accretion onto supermassive black holes. In order to understand the relationship between black hole mass and breaks in the power spectral density (PSD), the long-term X-ray variability of NGC 4945 was studied over the energy range 8-30 keV. Observations occurred over the year 2006 using the Rossi X-ray Timing Explorer. The data was reduced using the package FTOOLS, most notably the scripts Rex and faxbary. Light curves were produced and a PSD was obtained using a Fast Fourier Transform algorithm. Preliminary studies of the light curve show greater X-ray variability at higher frequencies. This result complements previous studies of NGC 4945 by Martin Mueller. However, the PSD produced must go through further study before accurate results can be obtained. A way to account for the window function of the PSD must be found before the behavior at lower frequencies can be studied with accuracy and the relationship between black hole mass and the break in NGC 4945's PSD can be better understood. Further work includes exploration into ways to subtract the window function from …
Date: August 29, 2007
Creator: Miller, Amara
Object Type: Report
System: The UNT Digital Library
Optical Cluster-Finding with an Adaptive Matched-Filter Technique: Algorithm and Comparison with Simulations (open access)

Optical Cluster-Finding with an Adaptive Matched-Filter Technique: Algorithm and Comparison with Simulations

We present a modified adaptive matched filter algorithm designed to identify clusters of galaxies in wide-field imaging surveys such as the Sloan Digital Sky Survey. The cluster-finding technique is fully adaptive to imaging surveys with spectroscopic coverage, multicolor photometric redshifts, no redshift information at all, and any combination of these within one survey. It works with high efficiency in multi-band imaging surveys where photometric redshifts can be estimated with well-understood error distributions. Tests of the algorithm on realistic mock SDSS catalogs suggest that the detected sample is {approx} 85% complete and over 90% pure for clusters with masses above 1.0 x 10{sup 14}h{sup -1} M and redshifts up to z = 0.45. The errors of estimated cluster redshifts from maximum likelihood method are shown to be small (typically less that 0.01) over the whole redshift range with photometric redshift errors typical of those found in the Sloan survey. Inside the spherical radius corresponding to a galaxy overdensity of {Delta} = 200, we find the derived cluster richness {Lambda}{sub 200} a roughly linear indicator of its virial mass M{sub 200}, which well recovers the relation between total luminosity and cluster mass of the input simulation.
Date: October 29, 2007
Creator: Dong, Feng; Pierpaoli, Elena; Gunn, James E. & Wechsler, Risa H.
Object Type: Article
System: The UNT Digital Library
ILC Electron Source Injector Simuations (open access)

ILC Electron Source Injector Simuations

As part of the global project aimed at proposing an efficient design for the ILC (International Linear Collider), we simulated possible setups for the electron source injector, which will provide insight into how the electron injector for the ILC should be designed in order to efficiently accelerate the electron beams through the bunching system. This study uses three types of software: E-Gun to simulate electron beam emission, Superfish to calculate solenoidal magnetic fields, and GPT (General Particle Tracer) to trace charged particles after emission through magnetic fields and subharmonic bunchers. We performed simulations of the electron source injector using various electron gun bias voltages (140kV - 200kV), emitted beam lengths (500ps - 1ns) and radii (7mm - 10mm), and electromagnetic field strengths of the first subharmonic buncher (5 - 20 MV/m). The results of the simulations show that for the current setup of the ILC, a modest electron gun bias voltage ({approx}140kV) is sufficient to achieve the required bunching of the beam in the injector. Extensive simulations of parameters also involving the second subharmonic buncher should be performed in order to gain more insight into possible efficient designs for the ILC electron source injector.
Date: August 29, 2007
Creator: Lakshmanan, Manu & /Cornell U., LNS /SLAC
Object Type: Report
System: The UNT Digital Library
Development of 50 kW Fuel Processor for Stationary Fuel Cell Applications (open access)

Development of 50 kW Fuel Processor for Stationary Fuel Cell Applications

The objective of the project was to develop and test a fuel processor capable of producing high hydrogen concentration (>98%) with less than ppm quantities of carbon dioxide and carbon monoxide at lower capital cost and higher efficiency, compared to conventional natural gas reformers. It was intended that we achieve our objective by developing simple reactor/process design, and high durability CO2 absorbents, to replace pressure swing adsorption (PSA) or membrane separators. Cost analysis indicated that we would not meet DOE cost goals so the project was terminated before construction of the full scale fuel processor. The work on adsorbent development was focused on the development of calcium oxide-based reversible CO2 absorbents with various microstructures and morphologies to determine the optimum microstructure for long-term reversible CO2 absorption. The effect of powder production process variables was systematically studied including: the final target compositions, the reagents from which the final products were derived, the pore forming additives, the processing time and temperature. The sorbent materials were characterized in terms of their performance in the reversible reaction with CO2 and correlation made to their microstructure.
Date: August 29, 2007
Creator: Stevens, James F.; Krishnamurthy, Balaji; Atanassova, Paolina & Spilker, Kerry
Object Type: Report
System: The UNT Digital Library
NSLS-II DESIGN: A NOVEL APPROACH TO LIGHT SOURCE DESIGN (open access)

NSLS-II DESIGN: A NOVEL APPROACH TO LIGHT SOURCE DESIGN

The NSLS-II storage ring will be a replacement for the existing two NSLS light sources, which although innovative when proposed, have been exceeded by modern light source designs. NSLS-II design takes a new approach toward providing users with the very bright beams after commissioning and a strategy of evolving to higher brightness beams as more ID devices are installed during its operations. This is achieved not by pushing the basic lattice to lower emittance, an approach that hits severe limits in the control of the dynamic aperture of an ever increasing non-linear lattice. Our approach is rather to reduce the natural emittance using damping wigglers, in addition to damping from the user undulator's. Details on the lattice design are presented.
Date: January 29, 2007
Creator: KRAMER,S.
Object Type: Article
System: The UNT Digital Library
VOC and HAP recovery using ionic liquids (open access)

VOC and HAP recovery using ionic liquids

During the manufacture of wood composites, paper, and to a lesser extent, lumber, large amounts of volatile organic compounds (VOCs) such as terpenes, formaldehyde, and methanol are emitted to air. Some of these compounds are hazardous air pollutants (HAPs). The air pollutants produced in the forest products industry are difficult to manage because the concentrations are very low. Presently, regenerative thermal oxidizers (RTOs and RCOs) are commonly used for the destruction of VOCs and HAPs. RTOs consume large amounts of natural gas to heat air and moisture. The combustion of natural gas generates increased CO2 and NOx, which have negative implications for global warming and air quality. The aforementioned problems are addressed by an absorption system containing a room-temperature ionic liquid (RTIL) as an absorbent. RTILs are salts, but are in liquid states at room temperature. RTILs, an emerging technology, are receiving much attention as replacements for organic solvents in industrial processes with significant cost and environmental benefits. Some of these processes include organic synthesis, extraction, and metal deposition. RTILs would be excellent absorbents for exhausts from wood products facilities because of their unique properties: no measurable vapor pressure, high solubility of wide range of organic compounds, thermal stability to …
Date: May 29, 2007
Creator: Li, Michael R. Milota : Kaichang
Object Type: Report
System: The UNT Digital Library
INORGANIC PLUME DELINEATION USING SURFACE HIGH RESOLUTION ELECTRICAL RESISTIVITY AT THE BC CRIBS & TRENCHES SITE HANFORD (open access)

INORGANIC PLUME DELINEATION USING SURFACE HIGH RESOLUTION ELECTRICAL RESISTIVITY AT THE BC CRIBS & TRENCHES SITE HANFORD

A surface resistivity survey was conducted on the Hanford Site over a waste disposal trench that received a large volume of liquid inorganic waste. The objective of the survey was to map the extent of the plume that resulted from the disposal activities approximately 50 years earlier. The survey included six resistivity transects of at least 200m, where each transect provided two-dimensional profile information of subsurface electrical properties. The results of the survey indicated that a low resistivity plume resides at a depth of approximately 25-44 m below ground surface. The target depth was calibrated with borehole data of pore-water electrical conductivity. Due to the high correlation of the pore-water electrical conductivity to nitrate concentration and the high correlation of measured apparent resistivity to pore-water electrical conductivity, inferences were made that proposed the spatial distribution of the apparent resistivity was due to the distribution of nitrate. Therefore, apparent resistivities were related to nitrate, which was subsequently rendered in three dimensions to show that the nitrate likely did not reach the water table and the bounds of the highest concentrations are directly beneath the collection of waste sites.
Date: May 29, 2007
Creator: BENECKE, M.W.
Object Type: Article
System: The UNT Digital Library
HIGH LEVEL WASTE (HLW) SLUDGE BATCH 4 (SB4) WITH FRIT 418: RESULTS OF A PHASE II VARIABILITY STUDY (open access)

HIGH LEVEL WASTE (HLW) SLUDGE BATCH 4 (SB4) WITH FRIT 418: RESULTS OF A PHASE II VARIABILITY STUDY

In early October 2006, the Liquid Waste Organization (LWO) began to consider decanting Tank 40 at the end of Sludge Batch 3 (SB3) processing and transferring the aqueous phase from the decant to Tank 51. This transfer would be done to remove water added to Tank 40 by a slurry pump bearing water leak. Tank 40 decant water would be used to decrease Tank 51 yield stress and facilitate a transfer of Tank 51 to Tank 40. The projected composition of Sludge Batch 4 (SB4) was adjusted by LWO to reflect the impact of the Tank 40 decant leading to new projected compositions for SB4, designated as the 10-04-06 and the 10-10-06 compositions. A comparison between these SB4 compositions and those provided in June 2006 indicated that the new compositions are slightly higher in Al2O3, Fe2O3, and U3O8 and slightly lower in SiO2. The most dramatic change, however, is the new projection's Na2O concentration, which is more than 4.5 wt% lower than the June 2006 projection. This is a significant change due to the frit development team's approach of aligning the Na2O concentration in a candidate frit to the Na2O content of the sludge. Questions surfaced regarding the applicability of …
Date: January 29, 2007
Creator: Fox, K; Tommy Edwards, T; David Peeler, D; David Best, D; Irene Reamer, I & Phyllis Workman, P
Object Type: Report
System: The UNT Digital Library
Science & Technology Review May 2007 (open access)

Science & Technology Review May 2007

None
Date: March 29, 2007
Creator: Radousky, H. B.
Object Type: Report
System: The UNT Digital Library
SARC: Development and Support of a Sarcoma Research Consortium Infrastructure (open access)

SARC: Development and Support of a Sarcoma Research Consortium Infrastructure

SARC is a non-for-profit organization whose mission and vision is to advocate for the collaboration on the design of clinical trials on sarcoma, to further the knowledge regarding the diagnosis and treatment of sarcoma and provide accurate and up to date information to physicians, patients and families. The objectives are to assist in the development of the infrastructure for the continued growth and spectrum of clinical research, to facilitate biannual meeting of investigators, and to develop a preclinical research base that would design and conduct research that would improve the process of drug treatments selected for clinical research trials.
Date: October 29, 2007
Creator: Arkison, Jim
Object Type: Report
System: The UNT Digital Library
Pulsed Laser-Based X-Ray Sources for Rapid-Cool DT Layer Characterization (open access)

Pulsed Laser-Based X-Ray Sources for Rapid-Cool DT Layer Characterization

Ignition targets for the National Ignition Facility (NIF) will contain a cryogenically cooled {approx} 75 {micro}m-thick deuterium/tritium (DT) ice layer surrounded by a {approx} 150 {micro}m-thick beryllium (Be) shell [1]. Ignition target design optimization depends sensitively on the achievable inner surface quality of the ice layer and on the pressure of the DT gas inside the ice, which is determined by the temperature of the ice. The inner ice layer surface is smoothest at temperatures just below the DT ice/liquid/gas triple point (3T), but current ignition target designs require central gas pressures of 0.3 mg/cm3, corresponding to an ice layer temperature 1.5 K below the triple point (3T-1.5). At these lower temperatures, the ice layer quality degrades due to the formation of cracks and other features.
Date: August 29, 2007
Creator: Koch, J A; Dewald, E; Izumi, N; Kozioziemski, B; Landen, O & Siders, C
Object Type: Report
System: The UNT Digital Library