Resource Type

Language

AN INFORMATION STORAGE AND RETRIEVAL SYSTEM FOR IRRADIATION EFFECTS IN METALS (open access)

AN INFORMATION STORAGE AND RETRIEVAL SYSTEM FOR IRRADIATION EFFECTS IN METALS

An information storage and retrieval system (PIC) was developed, utilizing the IBM 7090 computer, for handling data pertaining to the effects of neutron irradiation on metals. The input includes a reference identification, an appropriate abstract or extract summarizing the article, code identification parameters analogous to those used by the ASM-SLA Literature Classification System, and special codes identifying relevant irradiation and testing parameters. The output contains the same data plus printing out the meaning of all special codes. Presently, the information storage consists of more than two hundred references representing several thousand lines of information. The system is both general and definitive, permitting the selection of a single piece of information or of many references dealing with a general field. It is possible to select material on the basis of one or more of the following factors: material, general or specific; type of literature; general or specific property such as mechanical tests or tensile tests; conditions of irradiation including type and level of flux, integrated flux, irradiation temperature, and reactor environment; test conditions such as temperature and environment; and general variables that might be controlling such as strain rate, specimen geometry, grain size, and fabrication history. It is felt that this …
Date: August 15, 1963
Creator: Bush, S. H.
System: The UNT Digital Library
Requirements for signal cables and off-line data processing (open access)

Requirements for signal cables and off-line data processing

The number and types of cables for various experiments planned for the ISABELLE storage rings are estimated, and the results of a questionnaire on anticipated data taking rates are discussed. Necessary data acquisition rates, data storage capabilities, and data processing rates are estimated. (PMA)
Date: August 15, 1977
Creator: Strand, R.
System: The UNT Digital Library
Metallic coating of microspheres (open access)

Metallic coating of microspheres

Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates.
Date: August 15, 1980
Creator: Meyer, S.F.
System: The UNT Digital Library
Superconducting Critical Field of Tantalum as a Function of Temperature and Pressure (open access)

Superconducting Critical Field of Tantalum as a Function of Temperature and Pressure

None
Date: August 15, 1961
Creator: Hinrichs, C. H. & Swenson, C. A.
System: The UNT Digital Library
Similarity-Guided Streamline Placement with Error Evaluation (open access)

Similarity-Guided Streamline Placement with Error Evaluation

Most streamline generation algorithms either provide a particular density of streamlines across the domain or explicitly detect features, such as critical points, and follow customized rules to emphasize those features. However, the former generally includes many redundant streamlines, and the latter requires Boolean decisions on which points are features (and may thus suffer from robustness problems for real-world data). We take a new approach to adaptive streamline placement for steady vector fields in 2D and 3D. We define a metric for local similarity among streamlines and use this metric to grow streamlines from a dense set of candidate seed points. The metric considers not only Euclidean distance, but also a simple statistical measure of shape and directional similarity. Without explicit feature detection, our method produces streamlines that naturally accentuate regions of geometric interest. In conjunction with this method, we also propose a quantitative error metric for evaluating a streamline representation based on how well it preserves the information from the original vector field. This error metric reconstructs a vector field from points on the streamline representation and computes a difference of the reconstruction from the original vector field.
Date: August 15, 2007
Creator: Chen, Y.; Cohen, J. D. & Krolik, J. H.
System: The UNT Digital Library
The Elimination of Oxides of Nitrogen from the Exhaust of a dieselEngine using cryogenic air separation (open access)

The Elimination of Oxides of Nitrogen from the Exhaust of a dieselEngine using cryogenic air separation

None
Date: August 15, 1997
Creator: Manikowski, A.; Noland, G. & Green, M. A.
System: The UNT Digital Library
Tile-based Level of Detail for the Parallel Age (open access)

Tile-based Level of Detail for the Parallel Age

Today's PCs incorporate multiple CPUs and GPUs and are easily arranged in clusters for high-performance, interactive graphics. We present an approach based on hierarchical, screen-space tiles to parallelizing rendering with level of detail. Adapt tiles, render tiles, and machine tiles are associated with CPUs, GPUs, and PCs, respectively, to efficiently parallelize the workload with good resource utilization. Adaptive tile sizes provide load balancing while our level of detail system allows total and independent management of the load on CPUs and GPUs. We demonstrate our approach on parallel configurations consisting of both single PCs and a cluster of PCs.
Date: August 15, 2007
Creator: Niski, K. & Cohen, J. D.
System: The UNT Digital Library
Poroelastic modeling of fracture-seismic wave interaction (open access)

Poroelastic modeling of fracture-seismic wave interaction

Rock containing a compliant, fluid-filled fracture can be viewed as one case of heterogeneous poroelastic media. When this fracture is subjected to seismic waves, a strong contrast in the elastic stiffness between the fracture itself and the background can result in enhanced grain-scale local fluid flow. Because this flow--relaxing the pressure building up within the fracture--can increase the dynamic compliance of the fracture and change energy dissipation (attenuation), the scattering of seismic waves can be enhanced. Previously, for a flat, infinite fracture, we derived poroelastic seismic boundary conditions that describe the relationship between a finite jump in the stress and displacement across a fracture, expressed as a function of the stress and displacement at the boundaries. In this paper, we use these boundary conditions to determine frequency-dependent seismic wave transmission and reflection coefficients. Fluid-filled fractures with a range of mechanical and hydraulic properties are examined. From parametric studies, we found that the hydraulic permeability of a fracture fully saturated with water has little impact on seismic wave scattering. In contrast, the seismic response of a partially water-saturated fracture and a heterogeneous fracture filled with compliant liquid (e.g., supercritical CO{sub 2}) depended on the fracture permeability.
Date: August 15, 2008
Creator: Nakagawa, Seiji
System: The UNT Digital Library
Baryon Triality And Neutrino Masses From An Anomalous FlavorU(1) (open access)

Baryon Triality And Neutrino Masses From An Anomalous FlavorU(1)

We construct a concise U(1){sub X} Froggatt-Nielsen model in which baryon triality, a discrete gauge Z{sub 3}-symmetry, arises from U(1){sub X} breaking. The proton is thus stable, however, R-parity is violated. With the proper choice of U(1){sub X} charges we can obtain neutrino masses and mixings consistent with an explanation of the atmospheric and solar neutrino anomalies in terms of neutrino oscillations, with no right-handed neutrinos required. The only mass scale apart from M{sub grav} is m{sub soft}.
Date: August 15, 2007
Creator: Dreiner, Herbi K.; Luhn, Christoph; Murayama, Hitoshi & Thormeier,Marc
System: The UNT Digital Library
Measurements of Branching Fractions for B+ -> rho+ gamma, B0 -> rho0 gamma, and B0 -> omega gamma (open access)

Measurements of Branching Fractions for B+ -> rho+ gamma, B0 -> rho0 gamma, and B0 -> omega gamma

The authors present branching fraction measurements for the radiative decays B{sup +} {yields} {rho}{sup +}{gamma}, B{sup 0} {yields} {rho}{sup 0}{gamma}, and B{sup 0} {yields} {omega}{gamma}. The analysis is based on a data sample of 465 million B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy B Factory located at the Stanford Linear Accelerator Center (SLAC). They find {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) = (1.20{sub -0.37}{sup +0.42} {+-} 0.20) x 10{sup -6}, {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) = (0.97{sub -0.22}{sup +0.24} {+-} 0.06) x 10{sup -6}, and a 90% C.L. upper limit {Beta}(B{sup 0} {yields} {omega}{gamma}) < 0.9 x 10{sup -6}, where the first error is statistical and the second is systematic. They also measure the isospin-violating quantity {Lambda}(B{sup +} {yields} {rho}{sup +}{gamma})/2{Lambda}(B{sup 0} {yields} {rho}{sup 0}{gamma}) - 1 = -0.43{sub -0.22}{sup +0.25} {+-} 0.10.
Date: August 15, 2008
Creator: Aubert, B.
System: The UNT Digital Library
Search For B --> K* Nu Anti-Nu Decays (open access)

Search For B --> K* Nu Anti-Nu Decays

We present a search for the decays B {yields} K* {nu}{bar {nu}} using 454 x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We first select an event sample where one B is reconstructed in a semileptonic or hadronic mode with one charmed meson. The remaining particles in the event are then examined to search for a B {yields} K* {nu}{bar {nu}} decay. The charged K* is reconstructed as K*{sup +} {yields} K{sub S}{sup 0}{pi}{sup +} or K*{sup +} {yields} K{sup +}{pi}{sup 0}; the neutral K* is identified in K*{sup 0} {yields} K{sup +}{pi}{sup -} mode. We establish upper limits at 90% confidence level of {Beta}(B{sup +} {yields} K*{sup +} {nu}{bar {nu}}) < 8 x 10{sup -5}, {Beta}(B{sup 0} {yields} K*{sup 0} {nu}{bar {nu}}) < 12 x 10{sup -5}, and {Beta}(B {yields} K* {nu}{bar {nu}}) < 8 x 10{sup -5}.
Date: August 15, 2008
Creator: Aubert, B.
System: The UNT Digital Library
Spectroscopic Confirmation of the Fifth Image of SDSS J1004+4112 and Implications for the M_BH-sigma_* Relation at z=0.68 (open access)

Spectroscopic Confirmation of the Fifth Image of SDSS J1004+4112 and Implications for the M_BH-sigma_* Relation at z=0.68

We present the results of deep spectroscopy for the central region of the cluster lens SDSS J1004+4112 with the Subaru telescope. A secure detection of an emission line of the faint blue stellar object (component E) near the center of the brightest cluster galaxy (G1) confirms that it is the central fifth image of the lensed quasar system. In addition, we measure the stellar velocity dispersion of G1 to be {sigma}{sub *} = 352 {+-} 13 km s{sup -1}. We combine these results to obtain constraints on the mass M{sub BH} of the putative black hole (BH) at the center of the inactive galaxy G1, and hence on the M{sub BH}-{sigma}{sub *} relation at the lens redshift z{sub l} = 0.68. From detailed mass modeling, we place an upper limit on the black hole mass, M{sub BH} < 2.1 x 10{sup 10} M{sub {circle_dot}} at 1{sigma} level (< 3.1 x 10{sup 10}M{sub {circle_dot}} at 3{sigma}), which is consistent with black hole masses expected from the local and redshift-evolved M{sub BH}-{sigma}{sub *} relations, M{sub BH} {approx} 10{sup 9}-10{sup 10} M{sub {circle_dot}}.
Date: August 15, 2008
Creator: Inada, Naohisa; Oguri, Masamune; Falco, Emilio E.; Broadhurst, Tom J.; Ofek, Eran O.; Kochanek, Christopher S. et al.
System: The UNT Digital Library
Sequestering the Gravitino: Neutralino Dark Matter in Gauge Mediation (open access)

Sequestering the Gravitino: Neutralino Dark Matter in Gauge Mediation

In conventional models of gauge-mediated supersymmetry breaking, the lightest supersymmetric particle (LSP) is invariably the gravitino. However, if the supersymmetry breaking sector is strongly coupled, conformal sequestering may raise the mass of the gravitino relative to the remaining soft supersymmetry-breaking masses. In this letter, we demonstrate that such conformal dynamics in gauge-mediated theories may give rise to satisfactory neutralino dark matter while simultaneously solving the flavor and {mu}/B{mu} problems.
Date: August 15, 2008
Creator: Craig, Nathaniel J.; /Stanford U., Dept. Phys.; Green, Daniel & /SLAC /Stanford U., Dept. Phys.
System: The UNT Digital Library
Understanding High Voltage Vacuum Insulators for Microsecond Pulses (open access)

Understanding High Voltage Vacuum Insulators for Microsecond Pulses

High voltage insulation is one of the main areas of pulsed power research and development since the surface of an insulator exposed to vacuum can fail electrically at an applied field more than an order or magnitude below the bulk dielectric strength of the insulator. This is troublesome for applications where high voltage conditioning of the insulator and electrodes is not practical and where relatively long pulses, on the order of several microseconds, are required. Here we give a summary of our approach to modeling and simulation efforts and experimental investigations for understanding flashover mechanism. The computational work is comprised of both filed and particle-in-cell modeling with state-of-the-art commercial codes. Experiments were performed in using an available 100-kV, 10-{micro}s pulse generator and vacuum chamber. The initial experiments were done with polyethylene insulator material in the shape of a truncated cone cut at +45{sup o} angle between flat electrodes with a gap of 1.0 cm. The insulator was sized so there were no flashovers or breakdowns under nominal operating conditions. Insulator flashover or gap closure was induced by introducing a plasma source, a tuft of velvet, in proximity to the insulator or electrode.
Date: August 15, 2007
Creator: Javedani, J. B.; Goerz, D. A.; Houck, T. L.; Lauer, E. J.; Speer, R. D.; Tully, L. K. et al.
System: The UNT Digital Library
Historical Doses To The Public from Routine and Accidental Releases of Tritium - Lawrence Livermore National Laboratory, 1953 - 2005 (open access)

Historical Doses To The Public from Routine and Accidental Releases of Tritium - Lawrence Livermore National Laboratory, 1953 - 2005

Throughout fifty-three years of operations, an estimated 29,300 TBq of tritium have been released to the atmosphere at the Livermore site of Lawrence Livermore National Laboratory; about 75% of this was released accidentally as gaseous tritium in 1965 and 1970. Routine emissions contributed slightly more than 3,700 TBq gaseous tritium and about 2,800 TBq tritiated water vapor to the total. Mean annual doses (with 95% confidence intervals) to the most exposed member of the public were calculated for all years using the same model and the same assumptions. Because time-dependent tritium models require detailed meteorological data that were unavailable for the large releases, ingestion/inhalation dose ratios were derived from experience with UFOTRI. Even with assumptions to assure that doses would not be underestimated, all doses from routine and accidental releases were below the level (3.6 mSv) at which adverse health effects have been documented, and most were below the current regulatory limit of 100 {micro}Sv per year from releases to the atmosphere.
Date: August 15, 2007
Creator: Peterson, S & Raskob, W
System: The UNT Digital Library
Gamma-Ray Compton Light Source Development at Llnl (open access)

Gamma-Ray Compton Light Source Development at Llnl

A new class of tunable, monochromatic {gamma}-ray sources capable of operating at high peak and average brightness is currently being developed at LLNL for nuclear photoscience and applications. These novel systems are based on Compton scattering of laser photons by a high brightness relativistic electron beam produced by an rf photoinjector. A prototype, capable of producing > 10{sup 8} 0.7 MeV photons in a single shot, with a fractional bandwidth of 1%, and a repetition rate of 10 Hz, is currently under construction at LLNL; this system will be used to perform nuclear resonance fluorescence experiments. A new symmetrized S-band rf gun, using a Mg photocathode, will produce up to 1 nC of charge in an 8 ps bunch, with a normalized emittance modeled at 0.8 mm.mrad; electrons are subsequently accelerated up to 120 MeV to interact with a 500 mJ, 10 ps, 355 nm laser pulse and generate {gamma}-rays. The laser front end is a fiber-based system, using corrugated-fiber Bragg gratings for stretching, and drives both the frequency-quadrupled photocathode illumination laser and the Nd:YAG interaction laser. Two new technologies are used in the laser: a hyper-Michelson temporal pulse stacker capable of producing 8 ps square UV pulses, and a …
Date: August 15, 2007
Creator: Hartemann, F. V.; Anderson, S. G.; Gibson, D. J.; Hagmann, C. A.; Johnson, M. S.; Jovanovic, I. et al.
System: The UNT Digital Library
A Fuel Cell Power Supply for Long Duration Balloon Flights UsingStored Cryogens (open access)

A Fuel Cell Power Supply for Long Duration Balloon Flights UsingStored Cryogens

None
Date: August 15, 1997
Creator: Green, Michael A.; Manikowski, A.; Noland, G. & Golden, R.L.
System: The UNT Digital Library
Longitudinal Double Spin Asymmetry in Inclusive Jet Production at STAR (open access)

Longitudinal Double Spin Asymmetry in Inclusive Jet Production at STAR

This contribution reports on the first measurement of the longitudinal double-spin asymmetry A{sub LL} for the inclusive production of jets in polarized proton-proton collisions at {radical}s = 200 GeV. The data were collected with STAR at RHIC in the years 2003 and 2004, and correspond to a sampled integrated luminosity of 0.3 pb{sup -1} with beam polarizations up to 45%. The results on A{sub LL} cover jet transverse momenta 5 < p{sub T} < 17 GeV/c and agree with perturbative QCD evaluations based on deep-inelastic scattering parametrizations for the gluon polarization in the proton. The results disfavor large positive gluon polarization in the polarized proton.
Date: August 15, 2006
Creator: Kowalik, Katarzyna
System: The UNT Digital Library
Improving Estimation Accuracy of Aggregate Queries on Data Cubes (open access)

Improving Estimation Accuracy of Aggregate Queries on Data Cubes

In this paper, we investigate the problem of estimation of a target database from summary databases derived from a base data cube. We show that such estimates can be derived by choosing a primary database which uses a proxy database to estimate the results. This technique is common in statistics, but an important issue we are addressing is the accuracy of these estimates. Specifically, given multiple primary and multiple proxy databases, that share the same summary measure, the problem is how to select the primary and proxy databases that will generate the most accurate target database estimation possible. We propose an algorithmic approach for determining the steps to select or compute the source databases from multiple summary databases, which makes use of the principles of information entropy. We show that the source databases with the largest number of cells in common provide the more accurate estimates. We prove that this is consistent with maximizing the entropy. We provide some experimental results on the accuracy of the target database estimation in order to verify our results.
Date: August 15, 2008
Creator: Pourabbas, Elaheh & Shoshani, Arie
System: The UNT Digital Library
Zeroth-order inversion of transient head observations (open access)

Zeroth-order inversion of transient head observations

A high-frequency, asymptotic solution for transient head,appropriate for a medium containing smoothly varying heterogeneity,provides a basis for efficient inverse modeling. The semi analyticsolution is trajectory based, akin to ray methods used in modeling wavepropagation, and may be constructed by post processing the output of anumerical simulator. For high frequencies, the amplitude sensitivities,the relationship between changes in flow properties and changes in headampliude, are dominated by the phase term which may be computed directlyfrom the output of the simulator. Thus, transient head waveforms may beinverted with little more computation than is required to invert arrivaltimes. An applicatino to synthetic head values indicates that thetechnique can be used to improve the fit to waveforms. An application totransient head data from the Migration experiment in Switzerland revealsa narrow, high conductivity pathway within a 0.5 m thick zone offracturing.
Date: August 15, 2007
Creator: Vasco, D.W.
System: The UNT Digital Library
Study of the pi+pi-J//psi Mass Spectrum Via Initial State Radiation at BaBar (open access)

Study of the pi+pi-J//psi Mass Spectrum Via Initial State Radiation at BaBar

We present an update of the study of the Y(4260) resonance, produced in the process e{sup +}e{sup -} {yields} {gamma}{sub ISR} {pi}{sup +}{pi}{sup -} J/{psi} using initial-state radiation events at the PEP-II e{sup +}e{sup -} storage rings. This study is based on 454 fb{sup -1} of data recorded with the BABAR detector at a center-of-mass energy in the {Upsilon}(4S) resonance region. From a fit with a single non-relativistic Breit-Wigner shape we obtain updated parameters for the Y(4260) resonance which are m{sub Y} = 4252 {+-} 6{sub -3}{sup +2} MeV/c{sup 2} and {Lambda}{sub Y} = 105 {+-} 18{sub -6}{sup +4} MeV/c{sup 2}; we also measure {Beta}({pi}{sup +}{pi}{sup -} J/{psi}){Lambda}{sub e{sup +}e{sup -}} = (7.5 {+-} 0.9 {+-} 0.8) eV. We cannot confirm the recent BELLE observation of a broad structure around 4.05GeV/c{sup 2} in this decay mode.
Date: August 15, 2008
Creator: Aubert, Bernard
System: The UNT Digital Library
Application of structural-mechanics methods to the design of large tandem-mirror fusion devices (MFTF-B). Revision 1 (open access)

Application of structural-mechanics methods to the design of large tandem-mirror fusion devices (MFTF-B). Revision 1

The Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory requires state-of-the-art structural-mechanics methods to deal with access constraints for plasma heating and diagnostics, alignment requirements, and load complexity and variety. Large interactive structures required an integrated analytical approach to achieve a reasonable level of overall system optimization. The Tandem Magnet Generator (TMG) creates a magnet configuration for the EFFI calculation of electromagnetic-field forces that, coupled with other loads, form the input loading to magnet and vessel finite-element models. The analytical results provide the data base for detailed design of magnet, vessel, foundation, and interaction effects. 13 refs.
Date: August 15, 1985
Creator: Karpenko, V.N. & Ng, D.S.
System: The UNT Digital Library
Solar opacities constrained by solar neutrinos and solar oscillations (open access)

Solar opacities constrained by solar neutrinos and solar oscillations

This review discusses the current situation for opacities at the solar center, the solar surface, and for the few million kelvin temperatures that occur below the convection zone. The solar center conditions are important because they are crucial for the neutrino production, which continues to be predicted about 4 times that observed. The main extinction effects there are free-free photon absorption in the electric fields of the hydrogen, helium and the CNO atoms, free electron scattering of photons, and the bound-free and bound-bound absorption of photons by iron atoms with two electrons in the 1s bound level. An assumption that the iron is condensed-out below the convection zone, and the opacity in the central regions is thereby reduced, results in about a 25 percent reduction in the central opacity but only a 5 percent reduction at the base of the convection zone. Furthermore, the p-mode solar oscillations are changed with this assumption, and do not fit the observed ones as well as for standard models. A discussion of the large effective opacity reduction by weakly interacting massive particles also results in poor agreement with observed p-mode oscillation frequencies. The much larger opacities for the solar surface layers from the Los …
Date: August 15, 1989
Creator: Cox, A. N.
System: The UNT Digital Library
Titanium oxide cesium getters for low O/M FBR fuel pins (open access)

Titanium oxide cesium getters for low O/M FBR fuel pins

Fission product cesium may contribute to cladding strain in low oxygen-to-metal ratio (O/M) FBR fuel pins through localized reaction with fuel or UO/sub 2/ blanket pellets. Titanium oxide pellets were laboratory irradiation tested as candidate cesium getters for FBR fuel pins. Results indicate satisfactory performance.
Date: August 15, 1979
Creator: Wilson, C. N.; Gibby, R. L. & Weber, E. T.
System: The UNT Digital Library