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538
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154
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60
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36
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26
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6
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Evaluation of Roof Bolting Requirements Based on In-Mine Bolter Drilling Progress Report
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883 Matching Results
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Novel Optimization Methodology for Welding Process/Consumable Integration
None
Date:
January 15, 2006
Creator:
Quintana, M. A.; DebRoy, T.; Vitek, J. M. & Babu, S.
Object Type:
Report
System:
The UNT Digital Library
Physical test of a particle simulation model in a sheared granular system
We report a detailed comparison of a slow gravity driven sheared granular flow with a computational model performed with the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). To our knowledge, this is the first thorough test of the LAMMPS model with a laboratory granular flow. In the experiments, grains flow inside a silo with a rectangular cross-section, and are sheared by a rough boundary on one side and smooth boundaries on the other sides. Individual grain position and motion are measured using a particle index matching imaging technique where a fluorescent dye is added to the interstitial liquid which has the same refractive index as the glass beads. The boundary imposes a packing order, and the grains are observed to flow in layers which get progressively more disordered with distance from the walls. The computations use a Cundall--Strack contact model between the grains, using contact parameters that have been used in many other previous studies, and ignore the hydrodynamic effects of the interstitial liquid. Computations are performed to understand the effect of particle coefficient of friction, elasticity, contact model, and polydispersity on mean flow properties. After appropriate scaling, we find that the mean velocity of the grains and the number density …
Date:
January 15, 2009
Creator:
Rycroft, Chris; Orpe, Ashish & Kudrolli, Arshad
Object Type:
Article
System:
The UNT Digital Library
A Numerical Treatment of the Rf SQUID: I. General Properties andNoise Energy
We investigate the characteristics and noise performance of rf Superconducting Quantum Interference Devices (SQUIDs) by solving the corresponding Langevin equations numerically and optimizing the model parameters with respect to noise energy. After introducing the basic concepts of the numerical simulations, we give a detailed discussion of the performance of the SQUID as a function of all relevant parameters. The best performance is obtained in the crossover region between the dispersive and dissipative regimes, characterized by an inductance parameter {beta}{prime}{sub L} {triple_bond} 2{pi}LI{sub 0}/{Phi}{sub 0} {approx} 1; L is the loop inductance, I{sub 0} the critical current of the Josephson junction, and {phi}{sub 0} the flux quantum. In this regime, which is not well explored by previous analytical approaches, the lowest (intrinsic) values of noise energy are a factor of about 2 above previous estimates based on analytical approaches. However, several other analytical predictions, such as the inverse proportionality of the noise energy on the tank circuit quality factor and the square of the coupling coefficient between the tank circuit and the SQUID loop, could not be well reproduced. The optimized intrinsic noise energy of the rf SQUID is superior to that of the dc SQUID at all temperatures. Although for …
Date:
January 15, 2007
Creator:
Kleiner, Reinhold; Koelle, Dieter & Clarke, John
Object Type:
Article
System:
The UNT Digital Library
Quantum-Based Atomistic Simulation of Metals at Extreme Conditions
First-principles generalized pseudopotential theory (GPT) provides a fundamental basis for bridging the quantum-atomistic gap from density-functional quantum mechanics to large scale atomistic simulation in metals and alloys. In directionally-bonded bcc transition metals, advanced generation model GPT or MGPT potentials based on canonical d bands have been developed for Ta, Mo and V and successfully applied to a wide range of thermodynamic and mechanical properties at both ambient and extreme conditions of pressure and temperature, including high-pressure phase transitions, multiphase equation of state; melting and solidification; thermoelasticity; and the atomistic simulation of point defects, dislocations and grain boundaries needed for the multiscale modeling of plasticity and strength. Recent algorithm improvements have also allowed an MGPT implementation beyond canonical bands to achieve increased accuracy, extension to f-electron actinide metals, and high computational speed. A further advance in progress is the development temperature-dependent MGPT potentials that subsume electron-thermal contributions to high-temperature properties.
Date:
January 15, 2008
Creator:
Moriarty, J A; Glosli, J N; Hood, R Q; Klepeis, J E; Orlikowski, D A; Soderlind, P et al.
Object Type:
Article
System:
The UNT Digital Library
Special Issue on geophysics applied to detection and discrimination of unexploded ordnance
Unexploded ordnance (UXO) presents serious problems in Europe, Asia, as well as in the United States. Explosives and mines from World War I and World War II still turn up at European and Asian construction sites, backyard gardens, beaches, wildlife preserves and former military training grounds. The high rate of failure among munitions from 60-90 years ago is cited as one of the main reasons for such a high level of contamination. Apart from war activities, military training has resulted in many uncovered ordnance. It is especially true in the United States, where most UXO has resulted from decades of military training, exercises, and testing of weapons systems. Such UXO contamination prevents civilian land use, threatens public safety, and causes significant environmental concern. In light of this problem, there has been considerable interest shown by federal, state, and local authorities in UXO remediation at former U.S. Department of Defense sites. The ultimate goal of UXO remediation is to permit safe public use of contaminated lands. A Defense Science Board Task Force Report from 1998 lists some 1,500 sites, comprising approximately 15 million acres, that potentially contain UXO. The UXO-related activity for these sites consists of identifying the subareas that actually …
Date:
January 15, 2007
Creator:
Gasperikova, Erika; Gasperikova, Erika & Beard, Les P.
Object Type:
Article
System:
The UNT Digital Library
HIGH LEVEL WASTE MECHANCIAL SLUDGE REMOVAL AT THE SAVANNAH RIVER SITE F TANK FARM CLOSURE PROJECT
The Savannah River Site F-Tank Farm Closure project has successfully performed Mechanical Sludge Removal (MSR) using the Waste on Wheels (WOW) system for the first time within one of its storage tanks. The WOW system is designed to be relatively mobile with the ability for many components to be redeployed to multiple waste tanks. It is primarily comprised of Submersible Mixer Pumps (SMPs), Submersible Transfer Pumps (STPs), and a mobile control room with a control panel and variable speed drives. In addition, the project is currently preparing another waste tank for MSR utilizing lessons learned from this previous operational activity. These tanks, designated as Tank 6 and Tank 5 respectively, are Type I waste tanks located in F-Tank Farm (FTF) with a capacity of 2,840 cubic meters (750,000 gallons) each. The construction of these tanks was completed in 1953, and they were placed into waste storage service in 1959. The tank's primary shell is 23 meters (75 feet) in diameter, and 7.5 meters (24.5 feet) in height. Type I tanks have 34 vertically oriented cooling coils and two horizontal cooling coil circuits along the tank floor. Both Tank 5 and Tank 6 received and stored F-PUREX waste during their operating …
Date:
January 15, 2008
Creator:
Jolly, R & Bruce Martin, B
Object Type:
Article
System:
The UNT Digital Library
HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SUMMARY OF COMBINED THERMAL AND OPERATING LOADS WITH SEISMIC ANALYSIS
This report summarizes the results of the Double-Shell Tank Thermal and Operating Loads Analysis (TaLA) combined with the Seismic Analysis. This combined analysis provides a thorough, defensible, and documented analysis that will become a part of the overall analysis of record for the Hanford double-shell tanks (DSTs). The bases of the analytical work presented herein are two ANSYS{reg_sign} finite element models that were developed to represent a bounding-case tank. The TaLA model includes the effects of temperature on material properties, creep, concrete cracking, and various waste and annulus pressure-loading conditions. The seismic model considers the interaction of the tanks with the surrounding soil including a range of soil properties, and the effects of the waste contents during a seismic event. The structural evaluations completed with the representative tank models do not reveal any structural deficiencies with the integrity of the DSTs. The analyses represent 60 years of use, which extends well beyond the current date. In addition, the temperature loads imposed on the model are significantly more severe than any service to date or proposed for the future. Bounding material properties were also selected to provide the most severe combinations. While the focus of the analyses was a bounding-case tank, …
Date:
January 15, 2009
Creator:
TC, MACKEY; JE, DEIBLER; MW, RINKER; KI, JOHNSON; FG, ABATT; NK, KARRI et al.
Object Type:
Report
System:
The UNT Digital Library
Recent Process and Equipment Improvements to Increase High Level Waste Throughput at the Defense Waste Processing Facility
The Savannah River Site's (SRS) Defense Waste Processing Facility (DWPF) began stabilizing high level waste (HLW) in a glass matrix in 1996. Over the past few years, there have been several process and equipment improvements at the DWPF to increase the rate at which the high level waste can be stabilized. These improvements have either directly increased waste processing rates or have desensitized the process to upsets, thereby minimizing downtime and increasing production. Improvements due to optimization of waste throughput with increased HLW loading of the glass resulted in a 6% waste throughput increase based upon operational efficiencies. Improvements in canister production include the pour spout heated bellows liner (5%), glass surge (siphon) protection software (2%), melter feed pump software logic change to prevent spurious interlocks of the feed pump with subsequent dilution of feed stock (2%) and optimization of the steam atomized scrubber (SAS) operation to minimize downtime (3%) for a total increase in canister production of 12%. A number of process recovery efforts have allowed continued operation. These include the off gas system pluggage and restoration, slurry mix evaporator (SME) tank repair and replacement, remote cleaning of melter top head center nozzle, remote melter internal inspection, SAS pump …
Date:
January 15, 2008
Creator:
Odriscoll, R.; Allan Barnes, A.; Jim Coleman, J.; Timothy Glover, T.; Robert Hopkins, R.; Dan Iverson, D. et al.
Object Type:
Article
System:
The UNT Digital Library
CH-TRU Waste Content Codes (CH-TRUCON)
The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 …
Date:
January 15, 2005
Creator:
Westinghouse TRU Solutions LLC
Object Type:
Report
System:
The UNT Digital Library
Microarray-based whole-genome hybridization as a tool for determining procaryotic species relatedness
The definition and delineation of microbial species are of great importance and challenge due to the extent of evolution and diversity. Whole-genome DNA-DNA hybridization is the cornerstone for defining procaryotic species relatedness, but obtaining pairwise DNA-DNA reassociation values for a comprehensive phylogenetic analysis of procaryotes is tedious and time consuming. A previously described microarray format containing whole-genomic DNA (the community genome array or CGA) was rigorously evaluated as a high-throughput alternative to the traditional DNA-DNA reassociation approach for delineating procaryotic species relationships. DNA similarities for multiple bacterial strains obtained with the CGA-based hybridization were comparable to those obtained with various traditional whole-genome hybridization methods (r=0.87, P<0.01). Significant linear relationships were also observed between the CGA-based genome similarities and those derived from small subunit (SSU) rRNA gene sequences (r=0.79, P<0.0001), gyrB sequences (r=0.95, P<0.0001) or REP- and BOX-PCR fingerprinting profiles (r=0.82, P<0.0001). The CGA hybridization-revealed species relationships in several representative genera, including Pseudomonas, Azoarcus and Shewanella, were largely congruent with previous classifications based on various conventional whole-genome DNA-DNA reassociation, SSU rRNA and/or gyrB analyses. These results suggest that CGA-based DNA-DNA hybridization could serve as a powerful, high-throughput format for determining species relatedness among microorganisms.
Date:
January 15, 2008
Creator:
Wu, L.; Liu, X.; Fields, M.W.; Thompson, D.K.; Bagwell, C.E.; Tiedje, J. M. et al.
Object Type:
Article
System:
The UNT Digital Library
Adaptive Localization Regions for O(N) Density Functional Theory
A linear scaling approach for general and accurate pseudopotential Density Functional Theory calculations is presented. It is based on a Finite Difference discretization. Effective O(N) scaling is achieved by confining the orbitals in spherical localization regions. To improve accuracy and flexibility while computing the smallest possible number of orbitals, we propose an algorithm to adapt localization regions during computation. Numerical results for a polyacethylene chain and a magnesium oxide ring are presented.
Date:
January 15, 2008
Creator:
Fattebert, J
Object Type:
Article
System:
The UNT Digital Library
Gamma Ray Multiplicity of 252Cf Spontaneous Fission using LiBerACE
We are studying the gamma ray and neutron multiplicity of various fission processes, beginning with the spontaneous fission of {sup 252}Cf, for a variety of basic and applied science purposes. The Livermore-Berkeley Array for Collaborative Experiments (LiBerACE) consists of six high-purity germanium Clover detectors (HPGe) each enclosed by an array of 16 bismuth-germanate (BGO) detectors. These detectors were arranged in a cubic pattern around a 1 {micro}Ci {sup 252}Cf source to attempt to cover as much solid angle of gamma ray emission as possible with a high level of segmentation. The single-gamma detector response function is determined at several energies by tagging in a HPGe detector on the photopeak of one of two gamma rays in two-gamma ray calibration sources and observing the multiplicity of the remainder of the array. Summing these single-gamma responses in groups yields the response function of the array to higher multiplicity events, which are convolved with multiplicity distributions from theoretical models and compared to the measured results to test the models validity.
Date:
January 15, 2008
Creator:
Bleuel, D L; Bernstein, L A; Burke, J T; Heffner, M D; Norman, E B; Scielzo, N D et al.
Object Type:
Article
System:
The UNT Digital Library
Real-time x-ray absorption spectroscopy of uranium, iron, and manganese in contaminated sediments during bioreduction
The oxidation status of uranium in sediments is important because the solubility of this toxic and radioactive element is much greater for U(VI) than for U(IV) species. Thus, redox manipulation to promote precipitation of UO{sub 2} is receiving interest as a method to remediate U-contaminated sediments. Presence of Fe and Mn oxides in sediments at much higher concentrations than U requires understanding of their redox status as well. This study was conducted to determine changes in oxidation states of U, Fe, and Mn in U-contaminated sediments from Oak Ridge National Laboratory. Oxidation states of these elements were measured in real-time and nondestructively using X-ray absorption spectroscopy, on sediment columns supplied with synthetic groundwater containing organic carbon (OC, 0, 3, 10, 30 and 100 mM OC as lactate) for over 400 days. In sediments supplied with OC {ge} 30 mM, 80% of the U was reduced to U(IV), with transient reoxidation at about 150 days. Mn(III,IV) oxides were completely reduced to Mn(II) in sediments infused with OC {ge} 3 mM. However, Fe remained largely unreduced in all sediment columns, showing that Fe(III) can persist as an electron acceptor in reducing sediments over long times. This result in combination with the complete …
Date:
January 15, 2008
Creator:
Tokunaga, Tetsu; Tokunaga, T.K.; Wan, J.; Kim, Y.; Sutton, S.R.; Newville, M. et al.
Object Type:
Article
System:
The UNT Digital Library
Ultrafast dynamics of strong-field dissociative ionization ofCH2Br2 probed by femtosecond soft x-ray transient absorption spectroscopy
Femtosecond time-resolved soft x-ray transient absorption spectroscopy based on a high-order harmonic generation source is used to investigate the dissociative ionization of CH{sub 2}Br{sub 2} induced by 800 nm strong-field irradiation. At moderate peak intensities (2.0 x 10{sup 14} W/cm{sup 2}), strong-field ionization is accompanied by ultrafast C-Br bond dissociation, producing both neutral Br ({sup 2}P{sub 3/2}) and Br* ({sup 2}P{sub 1/2}) atoms together with the CH{sub 2}Br{sup +} fragment ion. The measured rise times for Br and Br* are 130 {+-} 22 fs and 74 {+-} 10 fs, respectively. The atomic bromine quantum state distribution shows that the Br/Br* population ratio is 8.1 {+-} 3.8 and that the Br {sup 2}P{sub 3/2} state is not aligned. The observed product distribution and the timescales of the photofragment appearances suggest that multiple field-dressed potential energy surfaces are involved in the dissociative ionization process. In addition, the transient absorption spectrum of CH{sub 2}Br{sub 2}{sup +} suggests that the alignment of the molecule relative to the polarization axis of the strong-field ionizing pulse determines the electronic symmetry of the resulting ion; alignment of the Br-Br, H-H, and C{sub 2} axis of the molecule along the polarization axis results in the production of the …
Date:
January 15, 2008
Creator:
Loh, Zhi-Heng & Leone, Stephen R.
Object Type:
Article
System:
The UNT Digital Library
Mechanical properties of granular materials: A variational approach to grain-scale simulations
The mechanical properties of cohesionless granular materials are evaluated from grain-scale simulations. A three-dimensional pack of spherical grains is loaded by incremental displacements of its boundaries. The deformation is described as a sequence of equilibrium configurations. Each configuration is characterized by a minimum of the total potential energy. This minimum is computed using a modification of the conjugate gradient algorithm. Our simulations capture the nonlinear, path-dependent behavior of granular materials observed in experiments. Micromechanical analysis provides valuable insight into phenomena such as hysteresis, strain hardening and stress-induced anisotropy. Estimates of the effective bulk modulus, obtained with no adjustment of material parameters, are in agreement with published experimental data. The model is applied to evaluate the effects of hydrate dissociation in marine sediments. Weakening of the sediment is quantified as a reduction in the effective elastic moduli.
Date:
January 15, 2009
Creator:
Holtzman, R.; Silin, D.B. & Patzek, T.W.
Object Type:
Article
System:
The UNT Digital Library
Grid Computing Education Support
The GGF Student Scholar program enabled GGF the opportunity to bring over sixty qualified graduate and under-graduate students with interests in grid technologies to its three annual events over the three-year program.
Date:
January 15, 2008
Creator:
Crumb, Steven
Object Type:
Report
System:
The UNT Digital Library
300 Area D4 Project Fiscal Year 2007 Building Completion Report
This report documents the deactivation, decontamination, decommissioning, and demolition (D4) of twenty buildings in the 300 Area of the Hanford Site. The D4 of these facilties included characterization, engineering, removal of hazardous and radiologically contaminated materials, equipment removal, utility disconnection, deactivation, decontamination, demolition of the structure, and stabilization or removal of the remaining slab and foundation, as appropriate.
Date:
January 15, 2009
Creator:
Westberg, R. A.
Object Type:
Report
System:
The UNT Digital Library
Cotton Chopper
Patent for cotton chopper. This invention is on a wheel mounted frame and is adjustable for cutting out sections at desired intervals. Illustration included.
Date:
January 15, 1907
Creator:
Walter, William Thomas
Object Type:
Patent
System:
The Portal to Texas History
Composition Fuel
Patent for "a new and useful improvement in composition fuel, the object being to produce fuel in compact form which will burn quickly, rapidly generating an intense heat, and leaving but a small quantity of a residue or ash" (lines 10-15).
Date:
January 15, 1901
Creator:
Patterson, Warren A.
Object Type:
Patent
System:
The Portal to Texas History
Car Coupling
Patent for a rail cars coupler. Illustrations included.
Date:
January 15, 1907
Creator:
Howell, Jordan M. & Walker, Abraham L.
Object Type:
Patent
System:
The Portal to Texas History
Carriage Bow Support
Patent for a carriage bow support. This invention is designed for use with buggies and absorb shock and jarring motions. Illustration included.
Date:
January 15, 1907
Creator:
Ledbetter, Rufus C.
Object Type:
Patent
System:
The Portal to Texas History
Glovebox enclosed dc plasma source for the determination of metals in plutonium
The direct current plasma source of a Beckman Spectraspan IIIB emission spectrometer was enclosed in a glovebox at Lawrence Livermore National Laboratory in December 1982. Since that time, the system has been used for the routine determination of alloy and impurity metals in plutonium. This paper presents the systematic steps involved in developing the glovebox and gives information regarding performance of the plasma in the glovebox and the effectiveness of containment of plutonium. 8 refs., 9 figs., 3 tabs.
Date:
January 15, 1986
Creator:
Morris, W.F.
Object Type:
Article
System:
The UNT Digital Library
Fabrication of Separator Demonstration Facility process vessel
The process vessel system is the central element in the Separator Development Facility (SDF). It houses the two major process components, i.e., the laser-beam folding optics and the separators pods. This major subsystem is the critical-path procurement for the SDF project. Details of the vaious parts of the process vessel are given.
Date:
January 15, 1985
Creator:
Oberst, E.F.
Object Type:
Report
System:
The UNT Digital Library
Benzene distribution in product streams from in-tank processing
Benzene is the major product of radiolytic decomposition of tetraphenylborate salts during in-tank salt decontamination. Its production rate has been measured at the Savannah River Laboratory (SR) and at the University of Florida under various conditions of importance to the in-tank process. Recent work has been concerned with the extent of decomposition for long storage periods, and the composition of the product streams from the process. The major results from this work are: the stored potassium tetraphenylborate precipitate will decompose at a rate of 7.3 {plus minus} 1.1% per year; the major products of the decomposition are benzene, phenol, biphenyl, and phenylboric acid; decomposition is directly proportional to the total dose and is unaffected by dose rate; the decomposition produces acidic compounds which will cause a decrease in the pH of the storage tank. 13 refs., 6 figs., 6 tabs.
Date:
January 15, 1987
Creator:
Walker, D. D.
Object Type:
Report
System:
The UNT Digital Library