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Inclusive electron scattering at high Q/sup 2/ in the region 1 < x < 3

Description: New inclusive electron scattering data at high Q/sup 2/ from nuclei taken in the x range unavailable to the free nucleon are presented. The ratios of cross section per nucleon, (4/56)d sigma/sup Fe//d sigma/sup He/, show a plateau for 1.3 < x < 2.0 which has been suggested as a signature of quark clusters in nuclei. The subtraction of the quasielastic cross section from the inclusive spectra reveals that the data scale in x at low momentum transfer. A proposal for a new experiment is discussed. 16 refs., 6 figs.
Date: January 1, 1987
Creator: Day, D.
Partner: UNT Libraries Government Documents Department

Inclusive quasielastic and deep inelastic electron scattering at high energies

Description: With high electron energies a kinematic regime can be reached where it will be possible to separate quasielastic and deep inelastic scattering. We present a short description of these processes which dominate the inclusive spectrum. Using the highest momentum transfer data available to guide our estimates, we give the kinematic requirements and the cross sections expected. These results indicate that inclusive scattering at high q has a yet unfilled potential. 18 refs., 13 figs.
Date: January 1, 1990
Creator: Day, D.B.
Partner: UNT Libraries Government Documents Department

Inversion of Passive Electromagnetic Fields to Locate Weapons of Mass Destruction

Description: A resolution study, employing a 3D nonlinear optimization technique, has been undertaken to study the viability of magnetotelluric (MT) measurements to detect and characterize buried facilities that make weapons of mass destruction. A significant advantage of the MT method is that no active source is required because the method employs passive field emissions. Thus measurements can be carried out covertly. Findings indicate it is possible to image WMD facilities, including depth of burial and lateral extent if a sufficient number of measurements are taken on the perimeter of the facility. Moreover if a station measurement can be made directly over the facility then the resolution is improved accordingly. In all cases it was not possible to image the base of the facility with any confidence as well as provide any precise inferences on the facility electrical conductivity. This later finding, however, is really not that critical since knowledge of facility geometry is far more important than knowledge of its conductivity. For the WMD problem it is recommended that MT measurements be made solely with the magnetic field ratios. In this context it would then be possible to deploy with far greater ease small coils about a suspected facility and would allow for the measurements to be conducted in a more covert manner. Before testing such a measurement system in the field, however, it would be necessary to carry out a similar resolution analysis as was done with MT measurements based on electric and magnetic fields. This is necessary to determine sensitivity of the proposed measurement to underground facilities along with needed data coverage and quality. Such a study is indispensable in producing useful reconstructions of underground facilities.
Date: December 24, 1998
Creator: Day, D.M. & Newman, G.A.
Partner: UNT Libraries Government Documents Department

A basic parallel sparse eigensolver for structural dynamics

Description: In this work the basic Finite Element Tearing and Interconnecting (FETI) linear system solver and the PARPACK eigensolver are combined to compute the smallest modes of symmetric generalized eigenvalue problems that arise from structures modeled primarily by solid finite elements. Problems with over one million unknowns are solved. A comprehensive and relatively self-contained description of the FETI method is presented.
Date: February 3, 1998
Creator: Day, D.
Partner: UNT Libraries Government Documents Department

AN INTEGRATED HYDROGEN PRODUCTION-CO2 CAPTURE PROCESS FROM FOSSIL FUEL

Description: The major project objective is to determine the feasibility of using the char from coal and/or biomass pyrolysis, ammonia and CO{sub 2} emissions at smokestacks to produce clean hydrogen and a sequestered carbon fertilizer. During this work period, literature review has been completed. The project plan, design and test schedules were made on the basis of discussion with partner in experimental issues. Installation of pilot scale units was finished and major units tests were fully performed. Modification of the pyrolyzer, reformer and gas absorption tank have been done. Integration testing is performing recently. Lab scale tests are in operation phase. The experimental installations are discussed in this paper.
Date: September 1, 2004
Creator: Wang, Z.; Bota, K.B. & Day, D.
Partner: UNT Libraries Government Documents Department

An Integrated Hydrogen Producton-CO2 Capture Process from Fossil Fuel

Description: The major project objective is to determine the feasibility of using the char from coal and/or biomass pyrolysis, ammonia and CO2 emissions at smokestacks to produce clean hydrogen and a sequestered carbon fertilizer. During this work period, literature review has been completed. The project plan, design and test schedules were made on the basis of discussion with partner in experimental issues. Installation of pilot scale units was finished and major units tests were fully performed. Modification of the pyrolyzer, reformer and gas absorption tank have been done. Integration testing is performing recently. Lab scale tests have been performed. Field tests of char/fertilizer have been conducted. The experimental results are discussed in this paper.
Date: December 1, 2005
Creator: Wang, Z.; Bota, K.B. & Day, D.
Partner: UNT Libraries Government Documents Department

XRD Technique: A way to disseminate structural changes in iron-based amorphous materials

Description: Prevention of corrosion is a vital goal for the Department of Defense when billions of dollars are spent every year. Corrosion resistant materials have applications in all sort of military vehicles, and more importantly in naval vessels and submarines which come in contact with the seawater. It is known that corrosion resistance property can be improved by the used of structurally designed materials in the amorphous state where the atoms are arranged in a non-periodic fashion and specific atoms, tailored to the required properties can be interjected into the matrix for specific application. The XRD techniques reported here is to demonstrate the optimal conditions for characterization of these materials. The samples, which normally contain different compositions of Fe, Cr, B, Mo, Y, Mn, Si and W, are in the form of powders, ribbons and coatings. These results will be compared for the different forms of the sample which appears to correlate to the cooling rate during sample processing. In most cases, the materials are amorphous or amorphous with very small amount of crystallinity. In the ribbon samples for different compositions we observed that the materials are essentially amorphous. In most cases, starting from an amorphous powder sample, the coatings are also observed to be amorphous with a small amount of iron oxide on the surface, probably due to exposure to air.
Date: May 24, 2007
Creator: Saw, C K; Lian, T; Day, D & Farmer, J
Partner: UNT Libraries Government Documents Department

Application of the FETI Method to ASCI Problems: Scalability Results on a Thousand-Processors and Discussion of Highly Heterogeneous Problems

Description: We report on the application of the one-level FETI method to the solution of a class of structural problems associated with the Department of Energy's Accelerated Strategic Computing Initiative (ASCI). We focus on numerical and parallel scalability issues,and discuss the treatment by FETI of severe structural heterogeneities. We also report on preliminary performance results obtained on the ASCI Option Red supercomputer configured with as many as one thousand processors, for problems with as many as 5 million degrees of freedom.
Date: April 1, 1999
Creator: Bhardwaj, M.; Day, D.; Farhat, C.; Lesoinne, M.; Pierson, K & Rixen, D.
Partner: UNT Libraries Government Documents Department

Application of the FETI Method to ASCI Problems: Scalability Results on One Thousand Processors and Discussion of Highly Heterogeneous Problems

Description: We report on the application of the one-level FETI method to the solution of a class of substructural problems associated with the Department of Energy's Accelerated Strategic Computing Initiative (ASCI). We focus on numerical and parallel scalability issues, and on preliminary performance results obtained on the ASCI Option Red supercomputer configured with as many as one thousand processors, for problems with as many as 5 million degrees of freedom.
Date: April 1, 1999
Creator: Bhardwaj, M.; Day, D.; Farhat, C.; Lesoinne, M; Pierson, K. & Rixen, D.
Partner: UNT Libraries Government Documents Department

An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms. Annual progress report, September 15, 1996--September 14, 1997

Description: 'Objectives of this project are to: (1) investigate the glass composition and processing conditions that yield optimum properties for iron phosphate glasses for vitrifying radioactive waste, (2) determine the atomic structure of iron phosphate glasses and the structure-property relationships, (3) determine how the physical and structural properties of iron phosphate glasses are affected by the addition of simulated high level nuclear waste components, and (4) investigate the process and products of devitrification of iron phosphate waste forms. The glass forming ability of about 125 iron phosphate melts has been investigated in different oxidizing to reducing atmospheres using various iron oxide raw materials such as Fe{sub 2}O{sub 3}, FeO, Fe{sub 3}O{sub 4}, and FeC{sub 2}O{sub 4} 2H{sub 2}O. The chemical durability, redox equilibria between Fe(II) and Fe(III), crystallization behavior and structural features for these glasses and their crystalline forms have been investigated using a variety of techniques including Mossbauer spectroscopy, X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), Extended x-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) analysis, differential thermal and thermogravimetric analysis (DTA/TGA), and X-ray and neutron diffraction.'
Date: September 23, 1997
Creator: Day, D.E.; Ray, C.S. & Marasinghe, K.
Partner: UNT Libraries Government Documents Department

Cold-Crucible Design Parameters for Next Generation HLW Melters

Description: The cold-crucible induction melter (CCIM) design eliminates many materials and operating constraints inherent in joule-heated melter (JHM) technology, which is the standard for vitrification of high-activity wastes worldwide. The cold-crucible design is smaller, less expensive, and generates much less waste for ultimate disposal. It should also allow a much more flexible operating envelope, which will be crucial if the heterogeneous wastes at the DOE reprocessing sites are to be vitrified. A joule-heated melter operates by passing current between water-cooled electrodes through a molten pool in a refractory-lined chamber. This design is inherently limited by susceptibility of materials to corrosion and melting. In addition, redox conditions and free metal content have exacerbated materials problems or lead to electrical short-circuiting causing failures in DOE melters. In contrast, the CCIM design is based on inductive coupling of a water-cooled high-frequency electrical coil with the glass, causing eddycurrents that produce heat and mixing. A critical difference is that inductance coupling transfers energy through a nonconductive solid layer of slag coating the metal container inside the coil, whereas the jouleheated design relies on passing current through conductive molten glass in direct contact with the metal electrodes and ceramic refractories. The frozen slag in the CCIM design protects the containment and eliminates the need for refractory, while the corrosive molten glass can be the limiting factor in the JH melter design. The CCIM design also eliminates the need for electrodes that typically limit operating temperature to below 1200 degrees C. While significant marketing claims have been made by French and Russian technology suppliers and developers, little data is available for engineering and economic evaluation of the technology, and no facilities are available in the US to support testing. A currently funded project at the Idaho National Engineering and Environmental Laboratory (INEEL), is providing preliminary data on ...
Date: February 26, 2002
Creator: Gombert, D.; Richardson, J.; Aloy, A. & Day, D.
Partner: UNT Libraries Government Documents Department

Long-Term Corrosion Testing of Thermal Spray Coatings of Amorphous Metals: Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 and Fe48Mo14Cr15Y2C15B6

Description: Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of SAM2X5 also made it an effective neutron absorber, and suitable for criticality control applications.
Date: July 9, 2007
Creator: Farmer, J; Day, D; Lian, T; Saw, C; Hailey, P; Payer, J et al.
Partner: UNT Libraries Government Documents Department

An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms. 1998 annual progress report

Description: 'Certain high level wastes (HLW) in the US contain components such as phosphates, heavy metals, and halides which make them poorly suited for disposal in borosilicate glasses. Iron phosphate glasses appear to be a technically feasible alternative to borosilicate glasses for vitrifying these HLWs. The iron phosphate glasses mentioned above and their nuclear wasteforms are relatively new, so little is known about their atomic structure, redox equilibria, structure-property relationships, and crystallization products and characteristics. The objective of this research is to gain such information for the binary iron-phosphate glasses as well as iron phosphate wasteforms so that a comprehensive scientific assessment can be made of their usefulness in nuclear waste disposal. This report summarizes the work undertaken and completed in the first 20 months of a three year project. Approximately 250 samples, binary iron phosphate glasses and iron phosphate glasses containing one or two common nuclear waste components such as UO{sub 2} , Na{sub 2}O, Bi{sub 2}O{sub 3} , Cs{sub 2}O, SrO, and MoO{sub 3}, have been prepared. Weight loss has been used to measure the chemical durability and the redox equilibria between Fe(II) and Fe(III) has been investigated using Moessbauer spectroscopy. The atomic structure has been investigated using a variety of techniques including Mossbauer, Raman, X-ray absorption (XAS), and X-ray photoelectron (XPS) spectroscopies and neutron/high energy X-ray scattering. Glass forming and crystallization characteristics have been investigated using differential thermal analysis (DTA). In addition, information necessary for glass manufacturing such as suitable refractories and Joule heating parameters also have been obtained.'
Date: June 1, 1998
Creator: Day, D.E.; Ray, C.S.; Marasinghe, G.K.; Karabulut, M. & Fang, X.
Partner: UNT Libraries Government Documents Department

Application of Neutron-Absorbing Structural-Amorphous Metal (SAM) Coatings for Spent Nuclear Fuel (SNF) Container to Enhance Criticality Safety Controls

Description: Spent nuclear fuel contains fissionable materials ({sup 235}U, {sup 239}Pu, {sup 241}Pu, etc.). Neutron multiplication and the potential for criticality are enhanced by the presence of a moderator during cask loading in water, water incursion in accidents conditions during spent fuel storage or transport. To prevent nuclear criticality in spent fuel storage, transportation, and during disposal, neutron-absorbing materials (or neutron poisons, such as borated stainless steel, Boral{trademark}, Metamic{trademark}, Ni-Gd, and others) would have to be applied. The success in demonstrating that the High-Performance Corrosion-Resistant material (HPCRM) can be thermally applied as coating onto base metal to provide for corrosion resistance for many naval applications raises the interest in applying the HPCRM to USDOE/OCRWM spent fuel management program. The fact that the HPCRM relies on the high content of boron to make the material amorphous--an essential property for corrosion resistance--and that the boron has to be homogeneously distributed in the HPCRM qualify the material to be a neutron poison.
Date: November 13, 2006
Creator: Choi, J; Lee, C; Day, D; Wall, M; Saw, C; MoberlyChan, W et al.
Partner: UNT Libraries Government Documents Department

Iron-Based Amorphous-Metals: High-Performance Corrosion-Resistant Material (HPCRM) Development

Description: An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was co-sponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the United States Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition; materials synthesis; thermal stability; corrosion resistance; environmental cracking; mechanical properties; damage tolerance; radiation effects; and important potential applications. Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional stainless steel and nickel-based materials, and are proving to have excellent wear properties, sufficient to warrant their use in earth excavation, drilling and tunnel boring applications. Large areas have been successfully coated with these materials, with thicknesses of approximately one centimeter. The observed corrosion resistance may enable ...
Date: January 9, 2008
Creator: Farmer, J C; Choi, J S; Saw, C; Haslam, J; Day, D; Hailey, P et al.
Partner: UNT Libraries Government Documents Department

Processing yttrium-barium-copper oxide superconductor zero gravity using a double float zone surface

Description: The effects of processing YBa{sub 2}Cu{sub 3}O{sub x} (Y123) superconductor in the near-zero gravity (0g) environment provided by the NASA KC-135 airplane flying on parabolic trajectories were studied. A new sheet float zone furnace, designed for this study, enabled fast temperature ramps. Up to an 18-gram sample was processed with each parabola. Samples of Y123 were processed as bulk sheets, composites containing Ag and Pd, and films deposited on single crystal Si and MgO substrates. The 0g-processed samples were multi-phase yet retained a localized Y123 stoichiometry where a single ground-based (1g) oxygen anneal at temperatures of 800 C recovered nearly 100-volume percent superconducting Y123. The 1g processed control samples remained multi-phase after the same ground-based anneal with less than 45 volume percent as superconducting Y123. The superconducting transition temperature was 91 K for both 0g and 1g processed samples. A 29 wt.% Ag/Y123 composite had a transition temperature of 93 K. Melt texturing of bulk Y123 in 0g produced aligned grains about a factor of three larger than in analogous 1g samples. Transport critical current densities were at or below 18 A/cm{sup 2}, due to the formation of cracks caused by the rapid heating rates required by the short time at 0g. Y123 deposited on single crystal Si and MgO in 0g was 30 vol.% y123 without an anneal. A weak superconducting transition at 80 K on MgO showed that substrate interactions occurred.
Date: April 1, 1997
Creator: Pettit, D. R.; Peterson, D. E.; Kubat-Martin, K. A.; Petrovic, J. J.; Sheinberg, H.; Coulter, Y. et al.
Partner: UNT Libraries Government Documents Department

Quasifree (e,e'p) Reactions and Proton Propagation in Nuclei

Description: The (e,e'p) reaction was studies on targets of C, Fe, and Au at momentum transfers squared Q{sup 2} of 0.6, 1.3, 1.8 and 3.3 GeV{sup 2} in a region of kinematics dominated by quasifree electron-proton scattering. Missing energy and missing momentum distributions are reasonably well described by plane wave impulse approximation calculations with Q{sup 2} and A dependent corrections that measure the attenuation of the final state protons.
Date: June 1, 1998
Creator: Abbott, David; Ahmidouch, A.; Amatuni, Ts.A.; Armstrong, C.; Arrington, J.; Assamagan, J.A. et al.
Partner: UNT Libraries Government Documents Department