Collection
United States Census Map Collection
882
Office of Scientific & Technical Information Technical Reports
114
Congressional Research Service Reports
64
Government Accountability Office Reports
15
Federal Register
8
Texas Attorney General Opinions
3
CyberCemetery Extracted Publications
2
Texas Register
2
Texas State Publications
2
CyberCemetery
1
Country
Year
Month
Day
Language
1,093 Matching Results
Results open in a new window/tab.
Results:
1 - 24 of
1,093
next
The AIG Rescue, Its Impact on Markets, and the Government's Exit Strategy
June report of the U.S. Congressional Oversight Panel describing their activities and findings regarding the impact of the 2007-2008 financial crisis on American International Group (AIG) and the subsequent rescue of the firm by the financial assistance received from the federal government.
Date:
June 10, 2010
Creator:
United States. Congressional Oversight Panel.
Object Type:
Report
System:
The UNT Digital Library
The Unique Treatment of GMAC Under the TARP
March report of the U.S. Congressional Oversight Panel describing their activities and findings regarding the state of the General Motors Acceptance Corporation during the 2007-2008 financial crisis and the financial assistance received by the firm by the federal government.
Date:
March 10, 2010
Creator:
United States. Congressional Oversight Panel.
Object Type:
Report
System:
The UNT Digital Library
Modular Coils and Plasma Configurations for Quasi-axisymmetric Stellarators
Characteristics of modular coils for quasi-axisymmetric stellarators that are related to the plasma aspect ratio, number of field periods and rotational transform have been examined systematically. It is observed that, for a given plasma aspect ratio, the coil complexity tends to increase with the increased number of field periods. For a given number of field periods, the toroidal excursion of coil winding is reduced as the plasma aspect ratio is increased. It is also clear that the larger the coil-plasma separation is, the more complex the coils become. It is further demonstrated that it is possible to use other types of coils to complement modular coils to improve both the physics and the modular coil characteristics.
Date:
September 10, 2010
Creator:
Ku, L. P. & Boozer, A. H.
Object Type:
Report
System:
The UNT Digital Library
The Higgs boson in the Standard Model theoretical constraints and a direct search in the wh channel at the Tevatron
We have presented results in two different yet strongly linked aspects of Higgs boson physics. We have learned about the importance of the Higgs boson for the fate of the Standard Model, being either only a theory limited to explaining phenomena at the electroweak scale or, if the Higgs boson lies within a mass range of 130 < m<sub>H</sub> < 160 GeV the SM would remain a self consistent theory up to highest energy scales O(m<sub>Pl</sub>). This could have direct implications on theories of cosmological inflation using the Higgs boson as the particle giving rise to inflation in the very early Universe, if it couples non-minimally to gravity, an effect that would only become significant at very high energies. After understanding the immense meaning of proving whether the Higgs boson exists and if so, at which mass, we have presented a direct search for a Higgs boson in associated production with a W boson in a mass range 100 < m<sub>H</sub> < 150 GeV. A light Higgs boson is favored regarding constraints from electroweak precision measurements. As a single analysis is not yet sensitive for an observation of the Higgs boson using 5.3 fb<sup>-1</sup> of Tevatron data, we set limits …
Date:
September 10, 2010
Creator:
Huske, Nils Kristian & (Germany)], Bielefeld Univ.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Some Considerations and Techniques for the Predictive Simulation of Global Instabilities in Tokamaks
This is a write-up of a lecture given at the Fourth ITER International Summer School held at the IFS, U. Texas in June 2010. A simple rigid plasma model is used to show that axisymmetric plasma instabilities (in two-dimensions) will occur on a resistive timescale and do not depend on the plasma mass. This is the justification for ignoring the inertial term in two-dimensional studies of plasma shape control and vertical stability. In three dimensions, it is not normally possible to ignore the inertial terms when computing plasma instabilities. This results in a stiff system of equations (with multiple timescales) in which the driving terms causing plasma instabilities are small compared with the stable compressive terms. Techniques are described for implicit time integration and for representing the vector fields in a way to facilitate obtaining accurate solutions for plasma instabilities when a strong background magnetic field is present.
Date:
September 10, 2010
Creator:
Jardin, S. C.
Object Type:
Report
System:
The UNT Digital Library
Wavelength measurement of n = 3 - n' = 3 transitions in highly charged tungsten ions
3s{sub 1/2} - 3p{sub 3/2} and 3p{sub 1/2} - 3d{sub 3/2} transitions have been studied in potassium-like W{sup 55+} through neon-like W{sup 64}+ ions at the electron-beam ion trap facility in Livermore. The wavelengths of the lines have been measured in high resolution relative to well known reference lines from oxygen and nitrogen ions. Using the high-energy SuperEBIT electron-beam ion trap and an R = 44.3 m grazing-incidence soft x-ray spectrometer, the lines were observed with a cryogenic charge-coupled device camera. The wavelength data for the sodium-like and magnesium-like tungsten lines are compared with theoretical predictions for ions along the isoelectronic sequences.
Date:
March 10, 2010
Creator:
Clementson, J & Beiersdorfer, P
Object Type:
Article
System:
The UNT Digital Library
The compressibility of cubic white and orthorhombic, rhombohedral, and simple cubic black phosphorus
The effect of pressure on the crystal structure of white phosphorus has been studied up to 22.4 GPa. The ?alpha phase was found to transform into the alpha' phase at 0.87 +- 0.04 GPa with a volume change of 0.1 +- 0.3 cc/mol. A fit of a second order Birch- Murnaghan equation to the data gave Vo = 16.94 ? 0.08 cc/mol and Ko = 6.7 +- 0.5 GPa for the alpha phase and Vo = 16.4 +- 0.1 cc/mol and Ko = 9.1 +- 0.3 GPa for the alpha' phase. The alpha' phase was found to transform to the A17 phase of black phosphorus at 2.68 +- 0.34 GPa and then with increasing pressure to the A7 and then simple cubic phase of black phosphorus. A fit of a second order Birch-Murnaghan equation to our data combined with previous measurements gave Vo = 11.43 +- 0.05 cc/mol and Ko = 34.7 +- 0.5 GPa for the A17 phase, Vo = 9.62 +- 0.01 cc/mol and Ko = 65.0 +- 0.6 GPa for the A7 phase and , Vo = 9.23 +- 0.01 cc/mol and Ko = 72.5 +- 0.3 GPa for the simple cubic phase.
Date:
March 10, 2010
Creator:
Clark, Simon M & Zaug, Joseph
Object Type:
Article
System:
The UNT Digital Library
Current Density and Plasma Displacement Near Perturbed Rational Surface
The current density in the vicinity of a rational surface of a force-free magnetic field subjected to an ideal perturbation is shown to be the sum of both a smooth and a delta-function distribution, which give comparable currents. The maximum perturbation to the smooth current density is comparable to a typical equilibrium current density and the width of the layer in which the current flows is shown to be proportional to the perturbation amplitude. In the standard linearized theory, the plasma displacement has an unphysical jump across the rational surface, but the full theory gives a continuous displacement.
Date:
October 10, 2010
Creator:
Boozer, A. H. & Pomphrey, N.
Object Type:
Report
System:
The UNT Digital Library
Studies in Optimal Configuration of the LTP
Brightness preservation requirements for ever brighter synchrotron radiation and free electron laser beamlines require surface slope tolerances of x-ray optics on the order of 0.2 mu rad, or better. Hence, the accuracy of dedicated surface slope metrology must be 0.1 mu rad, or even less. Achieving this level of measurement accuracy with the flagship instrument at synchrotron radiation metrology laboratories, the Long Trace Profiler (LTP), requires all significant sources of systematic, random, and instrumental drift errors to be identified, and reduced or eliminated. In this respect, the performance of certain components of the Advanced Light Source LTP-II design [Kirschman, et al., Proc. SPIE, 7077, 70770A-12 (2008)] is analyzed, considering the principal justification for inclusion of each component, possible systematic error due to the quality of its optical material, and drift effects due to generated heat, etc. We investigate the effects of replacement of the existing diode laser with a fiber-coupled laser light source, and demonstrate that reducing the number of components by using a single beam on the surface under test (SUT), rather than an original double beam maintains, or even improves the accuracy of measurement with our LTP. Based on the performance of the upgraded LTP, we trace the …
Date:
August 10, 2010
Creator:
McKinney, Wayne R.; Anders, Mark; Barber, Samuel K.; Domning, Edward E.; Lou, Yunian; Morrison, Gregory Y. et al.
Object Type:
Article
System:
The UNT Digital Library
Thermal Cooling Limits of Sbotaged Spent Fuel Pools
To develop the understanding and predictive measures of the post “loss of water inventory” hazardous conditions as a result of the natural and/or terrorist acts to the spent fuel pool of a nuclear plant. This includes the thermal cooling limits to the spent fuel assembly (before the onset of the zircaloy ignition and combustion), and the ignition, combustion, and the subsequent propagation of zircaloy fire from one fuel assembly to others
Date:
September 10, 2010
Creator:
Hughes, Dr. Thomas G. & Lin, Dr. Thomas F.
Object Type:
Report
System:
The UNT Digital Library
Sludge Batch Supplemental Srat Runs Effects of Yield Stress and Cycle Time Increase
The Defense Waste Processing Facility (DWPF) has transitioned from Sludge Batch 5 (SB5) processing to Sludge Batch 6 (SB6) processing. Phase III-Tank 40 Chemical Process Cell (CPC) flowsheet simulations have been completed to determine the initial processing conditions for the DWPF transition. The impact of higher yield stress (SB-25) and cycle time extension (SB6-26) on the physical and chemical effects of SB6 processing during the SRAT (Sludge Receipt and Adjustment Tank) cycle were evaluated. No significant impacts on the SRAT chemistry were noted during the higher yield stress run. In particular, no impact on mercury stripping was noted, indicating that settling of elemental mercury was not the primary factor in the low mercury recovery noted in the flowsheet testing. The SRAT product from this run retained the higher yield stress of the starting sludge. The run indicated that ultrasonication is an effective tool to increase the yield stress of simulants to targeted values and the chemistry of downstream processing is not impacted. Significant differences were noted in the cycle time extension test compared to the Phase III flowsheet baseline runs. Large decreases in the ammonia and hydrogen generation rates were noted along with reduced mercury stripping efficiency. The latter effect …
Date:
August 10, 2010
Creator:
Fernandez, A.
Object Type:
Report
System:
The UNT Digital Library
Electron and Photon Interactions in the Regime of Strong LPM Suppression
Most searches for ultra-high energy (UHE) astrophysical neutrinos look for radio emission from the electromagnetic and hadronic showers produced in their interactions. The radio frequency spectrum and angular distribution depend on the shower development, so are sensitive to the interaction cross sections. At energies above about 1016 eV (in ice), the Landau-Pomeranchuk-Migdal (LPM) effect significantly reduces the cross sections for the two dominant electromagnetic interactions: bremsstrahlung and pair production. At higher energies, above about 1020 eV, the photonuclear cross section becomes larger than that for pair production, and direct pair production and electronuclear interactions become dominant over bremsstrahlung. The electron interaction length reaches a maximum around 1021 eV, and then decreases slowly as the electron energy increases further. In this regime, the growth in the photon cross section and electron energy loss moderates the rise in nu e shower length, which rises from ~;;5 m at 1016 eV to ~;;40 m at 1019 eV and ~;;100 m at 1020 eV, but only to ~;;300 m at 1024 eV. In contrast, without photonuclear and electronuclear interactions, the shower length would be over 10 km at 1024 eV.
Date:
June 10, 2010
Creator:
Gerhardt, L. & Klein, S.
Object Type:
Article
System:
The UNT Digital Library
Determination of rotatable and frozen CoO spins and their relationship to exchange bias in CoO/Fe/Ag(001)
The exchange bias of epitaxially grown CoO/Fe/Ag(001) was investigated using X-ray Magnetic Circular Dichroism (XMCD) and X-ray Magnetic Linear Dichroism (XMLD) techniques. A direct XMLD measurement on the CoO layer during the Fe magnetization reversal shows that the CoO compensated spins are rotatable at thinner thickness and frozen, i.e. fixed in direction to the lattice, at larger thickness. By a quantitative determination of the rotatable and frozen CoO spins as a function of the CoO film thickness, we find the remarkable result that the exchange bias is well established before frozen spins are detectable in the CoO film, contrary to the common assumption that the majority of antiferromagnetic spins need to be frozen to generate the exchange bias. We further show that the rotatable/frozen CoO spins are uniformly distributed in the CoO film.
Date:
February 10, 2010
Creator:
Wu, J.; Park, J.; Kim, W.; Arenholz, E.; Liberati, M.; Scholl, A. et al.
Object Type:
Article
System:
The UNT Digital Library
Assessment of the Potential for Hydrogen Generation During Deactivation and Decommissioning of Reactor Vessels at the Savannah River Site
The R- and P-reactor vessels at the Savannah River Site (SRS) are being prepared for deactivation and decommissioning (D&D). D&D activities will consist primarily of physically isolating and stabilizing the reactor vessel by filling it with a grout material. The reactor vessels contain aluminum alloy materials, which pose a concern in that aluminum corrodes rapidly when it comes in contact with the alkaline grout. A product of the corrosion reaction is hydrogen gas and therefore potential flammability issues were assessed. A model was developed to calculate the hydrogen generation rate as the reactor is being filled with the grout material. Three options existed for the type of grout material for D&D of the reactor vessels. The grout formulation options included ceramicrete (pH 6-8), a calcium aluminate sulfate (CAS) based cement (pH 10), or Portland cement grout (pH 12.4). Corrosion data for aluminum in concrete were utilized as input for the model. The calculations considered such factors as the surface area of the aluminum components, the open cross-sectional area of the reactor vessel, the rate at which the grout is added to the reactor vessel, and temperature. Given the hydrogen generation rate, the hydrogen concentration in the vapor space of the …
Date:
November 10, 2010
Creator:
Wiersma, B.; Serrato, M. & Langton, C.
Object Type:
Article
System:
The UNT Digital Library
FABSOAR--A Fabry-Perot Spectrometer for Oxygen A-band Research Final Technical Report
Because this was a Phase I project, it did not add extensively to the body of A-band knowledge. There was no basic research performed on that subject. The principal addition was that a mechanical and optical design for a triple-etalon Fabry-Perot interferometer (FABSOAR) capable of A-band sensing was sketched out and shown to be within readily feasible instrument fabrication parameters. The parameters for the proposed triple-etalon Fabry-Perot were shown to be very similar to existing Fabry-Perots built by Scientific Solutions. The mechanical design for the FABSOAR instrument incorporated the design of previous Scientific Solutions imagers, condensing the three three-inch-diameter etalons into a single, sturdy tube. The design allowed for the inclusion of a commercial off-the-shelf (COTS) filter wheel and a thermocooled CCD detector from Andor. The tube has supports to mount to a horizontal or vertical opticaltable surface, and was to be coupled to a Scientific Solutions pointing head at the Millstone Hill Observatory in Massachusetts for Phase II calibration and testing.
Date:
September 10, 2010
Creator:
Watchorn, Steven
Object Type:
Report
System:
The UNT Digital Library
Strain Induced Magnetism in SrRuO3 Epitaxial Thin Films
Epitaxial SrRuO{sub 3} thin films were grown on SrTiO{sub 3}, (LaAlO{sub 3}){sub 0.3}(SrAlO{sub 3}){sub 0.7} and LaAlO{sub 3} substrates inducing different biaxial compressive strains. Coherently strained SrRuO{sub 3} films exhibit enhanced magnetization compared to previously reported bulk and thin film values of 1.1-1.6 {micro}{sub B} per formula unit. A comparison of (001) and (110) SrRuO{sub 3} films on each substrate indicates that films on (110) oriented have consistently higher saturated moments than corresponding (001) films. These observations indicate the importance of lattice distortions in controlling the magnetic ground state in this transitional metal oxide.
Date:
January 10, 2010
Creator:
Grutter, A.; Wong, F.; Arenholz, E.; Liberati, M. & Suzuki, Y.
Object Type:
Article
System:
The UNT Digital Library
Controlled Hydrogen Fleet and Infrastructure Analysis
This presentation summarizes controlled hydrogen fleet & infrastructure analysis undertaken for the DOE Fuel Cell Technologies Program.
Date:
June 10, 2010
Creator:
Wipke, K.; Sprik, S.; Kurtz, J. & Ramsden, T.
Object Type:
Presentation
System:
The UNT Digital Library
Magnetic Processing – A Pervasive Energy Efficient Technology for Next Generation Materials for Aerospace and Specialty Steel Markets
Thermomagnetic Magnetic Processing is an exceptionally fertile, pervasive and cross-cutting technology that is just now being recognized by several major industry leaders for its significant potential to increase energy efficiency and materials performance for a myriad of energy intensive industries in a variety of areas and applications. ORNL has pioneered the use and development of large magnetic fields in thermomagnetically processing (T-MP) materials for altering materials phase equilibria and transformation kinetics. ORNL has discovered that using magnetic fields, we can produce unique materials responses. T-MP can produce unique phase stabilities & microstructures with improved materials performance for structural and functional applications not achieved with traditional processing techniques. These results suggest that there are unprecedented opportunities to produce significantly enhanced materials properties via atomistic level (nano-) microstructural control and manipulation. ORNL (in addition to others) have shown that grain boundary chemistry and precipitation kinetics are also affected by large magnetic fields. This CRADA has taken advantage of ORNL’s unique, custom-designed thermo-magnetic, 9 Tesla superconducting magnet facility that enables rapid heating and cooling of metallic components within the magnet bore; as well as ORNL’s expertise in high magnetic field (HMF) research. Carpenter Technologies, Corp., is a a US-based industrial company, that provides …
Date:
September 10, 2010
Creator:
Mackiewicz-Ludtka, G.; Ludtka, G. M.; Ray, P. & Magee, J.
Object Type:
Report
System:
The UNT Digital Library
A Prognostic Method for Scheduling Maintenance on the P2- Marx Modulator
The SLAC National Accelerator Laboratory is developing a second generation Marx-type modulator for the ILC, the P2-Marx. The modulator is expected to operate reliably in excess of 10{sup 5} hours with minimum downtime. A prognostic system is being implemented with the development of the P2-Marx to monitor and track the health of key high voltage components. This paper discusses the way in which the prognostic system will be implemented and used to monitor the health of the P2-Marx modulator.
Date:
June 10, 2010
Creator:
Benwell, Andrew; Burkhart, Craig; Kemp, Mark; Macken, Koen; Nguyen, Minh; MacNair, Dave et al.
Object Type:
Article
System:
The UNT Digital Library
Ab initio Based Modeling of Radiation Effects in Multi-Component Alloys: Final Scientific/Technical Report
The project began March 13, 2006, allocated for three years, and received a one year extension from March 13, 2009 to March 12, 2010. It has now completed 48 of 48 total months. The project was focused on using ab initio methods to gain insights into radiation induced segregation (RIS) in Ni-Fe-Cr alloys. The project had the following key accomplishments • Development of a large database of ab initio energetics that can be used by many researchers in the future for increased understanding of this system. For example, we have the first calculations showing a dramatic stabilization effect of Cr-Cr interstitial dumbbells in Ni. • Prediction of both vacancy and interstitial diffusion constants for Ni-Cr and Ni-Fe for dilute Cr and Fe. This work included generalization of widely used multifrequency models to make use of ab initio derived energetics and thermodynamics. • Prediction of qualitative trends of RIS from vacancy and interstitial mechanisms, suggesting the two types of defect fluxes drive Cr RIS in opposite directions. • Detailed kinetic Monte Carlo modeling of diffusion by vacancy mechanism in Ni-Cr as a function of Cr concentration. The results demonstrate that Cr content can have a significant effect on RIS. • Development …
Date:
June 10, 2010
Creator:
Morgan, Dane
Object Type:
Report
System:
The UNT Digital Library
Prospective Type Ia supernova surveys from Dome A
Dome A, the highest plateau in Antarctica, is being developed as a site for an astronomical observatory. The planned telescopes and instrumentation and the unique site characteristics are conducive toward Type Ia supernova surveys for cosmology. A self-contained search and survey over 5 years can yield a spectro-photometric time series of ~;; 1000 z< 0:08 supernovae. These can serve to anchor the Hubble diagram and quantify the relationship between luminosities and heterogeneities within the Type Ia supernova class, reducing systematics. Larger aperture (>=4-m) telescopes are capable of discovering supernovae shortly after explosion out to z ~;; 3. These can be fed to space telescopes, and can isolate systematics and extend the redshift range over which we measure the expansion history of the universe.
Date:
March 10, 2010
Creator:
Kim, A.; Bonissent, A.; Christiansen, J. L.; Ealet, A.; Faccioli, L.; Gladney, L. et al.
Object Type:
Article
System:
The UNT Digital Library
Efficient Bulk Data Replication for the Earth System Grid
The Earth System Grid (ESG) community faces the difficult challenge of managing the distribution of massive data sets to thousands of scientists around the world. To move data replicas efficiently, the ESG has developed a data transfer management tool called the Bulk Data Mover (BDM). We describe the performance results of the current system and plans towards extending the techniques developed so far for the up- coming project, in which the ESG will employ advanced networks to move multi-TB datasets with the ulti- mate goal of helping researchers understand climate change and its potential impacts on world ecology and society.
Date:
March 10, 2010
Creator:
Sim, Alex; Gunter, Dan; Natarajan, Vijaya; Shoshani, Arie; Williams, Dean; Long, Jeff et al.
Object Type:
Article
System:
The UNT Digital Library
Beam Fields and Energy Dissipation Inside the the BE Beam Pipe of the Super-B Detector
We study the bunch field diffusion and energy dissipation in the beam pipe of the Super-B detector, which consists of two coaxial Be thin pipes (half a millimeter). Cooling water will run between these two pipes. Gold and nickel will be sputtered (several microns) onto the beryllium pipe at different sides. The Maxwell equations for the beam fields in these thin layers are solved numerically for the case of infinite pipes. We also calculate the amplitude of the electromagnetic fields outside the beam pipe, which may be noticeable as the beam current can reach 4 A in each beam. Results of simulations are used for the design of this central part of the Super-B detector.
Date:
September 10, 2010
Creator:
Novokhatski, Alexander & Sullivan, Michael
Object Type:
Article
System:
The UNT Digital Library
A direct measurement of rotatable and frozen CoO spins in exchange bias system of CoO/Fe/Ag(001)
The exchange bias of epitaxially grown CoO/Fe/Ag(001) was investigated using x-ray magnetic circular dichroism and x-ray magnetic linear dichroism (XMLD) techniques. A direct XMLD measurement on the CoO layer during the Fe magnetization reversal shows that the CoO compensated spins are rotatable at thinner thickness and frozen at larger thickness. By a quantitative determination of the rotatable and frozen CoO spins as a function of the CoO film thickness, we find the remarkable result that the exchange bias is well established before frozen spins are detectable in the CoO film. We further show that the rotatable and frozen CoO spins are uniformly distributed in the CoO film.
Date:
March 10, 2010
Creator:
Wu, J.; Park, J. S.; Kim, W.; Arenholz, E.; Liberati, M.; Scholl, A. et al.
Object Type:
Article
System:
The UNT Digital Library