Resource Type

States

Language

Hadron-hadron physics at high energy and luminosity (open access)

Hadron-hadron physics at high energy and luminosity

I review some recent theoretical issues relevant to the physics of hadron-hadron collisions. I discuss processes where either energy or luminosity is the most important feature and emphasize the need for experiments at luminosities of 10{sup 33}cm{sup -2}sec{sup 1} if the full range of physics options is to be thoroughly explored. 22 refs., 10 figs.
Date: November 8, 1989
Creator: Hinchliffe, I.
System: The UNT Digital Library
Geometric continuum regularization of quantum field theory (open access)

Geometric continuum regularization of quantum field theory

An overview of the continuum regularization program is given. The program is traced from its roots in stochastic quantization, with emphasis on the examples of regularized gauge theory, the regularized general nonlinear sigma model and regularized quantum gravity. In its coordinate-invariant form, the regularization is seen as entirely geometric: only the supermetric on field deformations is regularized, and the prescription provides universal nonperturbative invariant continuum regularization across all quantum field theory. 54 refs.
Date: November 8, 1989
Creator: Halpern, M.B. (California Univ., Berkeley, CA (USA). Dept. of Physics)
System: The UNT Digital Library
Functional Analysis of Metabolic Channeling and Regulation in Lignin Biosynthesis: A Computational Approach (open access)

Functional Analysis of Metabolic Channeling and Regulation in Lignin Biosynthesis: A Computational Approach

Article on the functional analysis of metabolic channeling and regulation in lignin biosynthesis.
Date: November 8, 2012
Creator: Lee, Yun; Escamilla-Treviño, Luis; Dixon, R. A. & Voit, Eberhard O.
System: The UNT Digital Library
Construction techniques for short iron-free dipole magnets (open access)

Construction techniques for short iron-free dipole magnets

A method was developed for economically fabricating short, wire-wound, steering magnets with maximum length, cosine-distributed, axial elements. This method utilizes multifunctional tooling to precisely flat-wind two-layer dipole halves that are subsequently reformed and encapsulated into semicylindrical form with confinement of the end turns into thin, half discs normal to the magnet axis. This paper addresses the magnet fabrication in detail, highlighting the inherent quality control features of the tooling, overall construction costs, and contemplated manufacturing enhancements.
Date: November 8, 1983
Creator: Harvey, A.R.
System: The UNT Digital Library
Assessing Recharge and Geological Model Uncertainty at the Climax Mine Area of the Nevada Test Site (open access)

Assessing Recharge and Geological Model Uncertainty at the Climax Mine Area of the Nevada Test Site

Hydrologic analyses are commonly based on a single conceptual-mathematical model. Yet hydrologic environments are open and complex, rendering them prone to multiple interpretations and mathematical descriptions. Considering conceptual model uncertainty is a critical process in hydrologic uncertainty assessment. This study assesses recharge and geologic model uncertainty for the Climax mine area of the Nevada Test Site, Nevada. Five alternative recharge models have been independently developed for Nevada and the Death Valley area of California. These models are (1) the Maxey-Eakin model, (2 and 3) a distributed parameter watershed model with and without a runon-runoff component, and (4 and 5) a chloride mass-balance model with two zero-recharge masks, one for alluvium and one for both alluvium and elevation. Similarly, five geological models have been developed based on different interpretations of available geologic information. One of them was developed by the U.S. Geological Survey for the Death Valley Regional Flow System (DVRFS) model; the other four were developed by Bechtel Nevada for the Yucca Flat Corrective Action Unit (CAU). The Climax mine area is in the northern part of the Yucca Flat CAU, which is within the DVRFS. A total of 25 conceptual models are thus formulated based on the five recharge …
Date: November 8, 2007
Creator: Ye, M.; Pohlmann, K.; Chapman, J. & Pohll, G.
System: The UNT Digital Library
Analysis of the SL-1 Accident Using RELAPS5-3D (open access)

Analysis of the SL-1 Accident Using RELAPS5-3D

On January 3, 1961, at the National Reactor Testing Station, in Idaho Falls, Idaho, the Stationary Low Power Reactor No. 1 (SL-1) experienced a major nuclear excursion, killing three people, and destroying the reactor core. The SL-1 reactor, a 3 MW{sub t} boiling water reactor, was shut down and undergoing routine maintenance work at the time. This paper presents an analysis of the SL-1 reactor excursion using the RELAP5-3D thermal-hydraulic and nuclear analysis code, with the intent of simulating the accident from the point of reactivity insertion to destruction and vaporization of the fuel. Results are presented, along with a discussion of sensitivity to some reactor and transient parameters (many of the details are only known with a high level of uncertainty).
Date: November 8, 2007
Creator: Francisco, A.D. and Tomlinson, E. T.
System: The UNT Digital Library
SUSY Les Houches Accord 2 (open access)

SUSY Les Houches Accord 2

The Supersymmetry Les Houches Accord (SLHA) [1] provides a universal set of conventions for conveying spectral and decay information for supersymmetry analysis problems in high energy physics. Here, we propose extensions of the conventions of the first SLHA to include various generalizations: the minimal supersymmetric standard model with violation of CP, R-parity, and flavor, as well as the simplest next-to-minimal model.
Date: November 8, 2007
Creator: Allanach, B.; Balazs, C.; Belanger, G.; Bernhardt, M.; Boudjema, F.; Choudhury, D. et al.
System: The UNT Digital Library
Direct Measurements of an increased threshold for stimulated Brillouin scattering with polarization smoothing in ignition hohlraum plasmas (open access)

Direct Measurements of an increased threshold for stimulated Brillouin scattering with polarization smoothing in ignition hohlraum plasmas

We demonstrate a significant reduction of stimulated Brillouin scattering by polarization smoothing. The intensity threshold is measured to increase by a factor of 1.7 {+-} 0.2 when polarization smoothing is applied. The results were obtained in a high-temperature (T{sub 3} {approx_equal} 3 keV) hohlraum plasma where filamentation is negligible in determining the backscatter threshold. These results are explained by an analytical model relevant to ICF plasma conditions that modifies the linear gain exponent to account for polarization smoothing.
Date: November 8, 2007
Creator: Froula, D; Divol, L; Berger, R L; London, R; Meezan, N; Neumayer, P et al.
System: The UNT Digital Library
Three dimensional modeling of Laser-Plasma interaction: benchmarking our predictive modeling tools vs. experiments (open access)

Three dimensional modeling of Laser-Plasma interaction: benchmarking our predictive modeling tools vs. experiments

We have developed a new target platform to study Laser Plasma Interaction in ignition-relevant condition at the Omega laser facility (LLE/Rochester)[1]. By shooting an interaction beam along the axis of a gas-filled hohlraum heated by up to 17 kJ of heater beam energy, we were able to create a millimeter-scale underdense uniform plasma at electron temperatures above 3 keV. Extensive Thomson scattering measurements allowed us to benchmark our hydrodynamic simulations performed with HYDRA[2]. As a result of this effort, we can use with much confidence these simulations as input parameters for our LPI simulation code pF3d[3]. In this paper, we show that by using accurate hydrodynamic profiles and full three-dimensional simulations including a realistic modeling of the laser intensity pattern generated by various smoothing options, whole beam three-dimensional linear kinetic modeling of stimulated Brillouin scattering reproduces quantitatively the experimental measurements(SBS thresholds, reflectivity values and the absence of measurable SRS). This good agreement was made possible by the recent increase in computing power routinely available for such simulations. These simulations accurately predicted the strong reduction of SBS measured when polarization smoothing is used.
Date: November 8, 2007
Creator: Divol, L; Berger, R; Meezan, N; Froula, D H; Dixit, S; Suter, L et al.
System: The UNT Digital Library
Transition to Turbulence and Effect of Initial Conditions on 3D Compressible Mixing in Planar Blast-wave-driven Systems (open access)

Transition to Turbulence and Effect of Initial Conditions on 3D Compressible Mixing in Planar Blast-wave-driven Systems

Perturbations on an interface driven by a strong blast wave grow in time due to a combination of Rayleigh-Taylor, Richtmyer-Meshkov, and decompression effects. In this paper, results from three-dimensional numerical simulations of such a system under drive conditions to be attainable on the National Ignition Facility [E. M. Campbell, Laser Part. Beams, 9(2), 209 (1991)] are presented. Using the multi-physics, adaptive mesh refinement, higher order Godunov Eulerian hydrocode, Raptor [L. H. Howell and J.A. Greenough, J. Comp. Phys. 184, 53 (2003)], the late nonlinear instability evolution, including transition to turbulence, is considered for various multimode perturbation spectra. The 3D post-transition state differs from the 2D result, but the process of transition proceeds similarly in both 2D and 3D. The turbulent mixing transition results in a reduction in the growth rate of the mixing layer relative to its pre-transition value and, in the case of the bubble front, relative to the 2D result. The post-transition spike front velocity is approximately the same in 2D and 3D. Implications for hydrodynamic mixing in core-collapse supernova are discussed.
Date: November 8, 2004
Creator: Miles, A R; Edwards, M J & Greenough, J A
System: The UNT Digital Library
Ion Beam Induced Surface Modulations from Nano to Pico: Optimizing Deposition During Erosion and Erosion During Deposition. (open access)

Ion Beam Induced Surface Modulations from Nano to Pico: Optimizing Deposition During Erosion and Erosion During Deposition.

Ion beams of sufficient energy to erode a surface can lead to surface modulations that depend on the ion beam, the material surface it impinges, and extrinsic parameters such as temperature and geometric boundary conditions. Focused Ion Beam technology both enables site-specific placement of these modulations and expedites research through fast, high dose and small efficient use of material. The DualBeam (FIB/SEM) enables in situ metrology, with movies observing ripple formation, wave motion, and the influence of line defects. Nanostructures (ripples of >400nm wavelength to dots spaced <40nm) naturally grow from atomically flat surfaces during erosion, however, a steady state size may or may not be achieved as a consequence of numerous controlled parameters: temperature, angle, energy, crystallography. Geometric factors, which can be easily invoked using a FIB, enable a controlled component of deposition (and/or redeposition) to occur during erosion, and conversely allow a component of etching to be incurred during (ion-beam assisted) deposition. High angles of ion beam inclination commonly lead to 'rougher' surfaces, however, the extreme case of 90.0{sup o} etching enables deposition of organized structures 1000 times smaller than the aforementioned, video-recorded nanostructures. Orientation and position of these picostructures (naturally quantized by their atomic spacings) may be …
Date: November 8, 2007
Creator: MoberlyChan, W J & Schalek, R
System: The UNT Digital Library
[Magazine Article: Hypocritical Oath] (open access)

[Magazine Article: Hypocritical Oath]

A copy of a newspaper article pertaining to Califonia's Proposition 186 and the reaction of the gay and lesbian community.
Date: November 8, 1994
Creator: unknown
System: The UNT Digital Library
Corrosion-resistant multilayer coatings for the 28-75 nm wavelength region (open access)

Corrosion-resistant multilayer coatings for the 28-75 nm wavelength region

Corrosion has prevented use of SiC/Mg multilayers in applications requiring good lifetime stability. We have developed Al-based barrier layers that dramatically reduce corrosion, while preserving high reflectance and low stress. The aforementioned advances may enable the implementation of corrosion-resistant, high-performance SiC/Mg coatings in the 28-75 nm region in applications such as tabletop EUV/soft x-ray laser sources and solar physics telescopes. Further study and optimization of corrosion barrier structures and coating designs is underway.
Date: November 8, 2011
Creator: Soufli, R.; Fernandez-Perea, Monica & Al, E. T.
System: The UNT Digital Library
The replacement of an electromagnetic primary sodium sampling pump in the Fast Flux Test Facility (open access)

The replacement of an electromagnetic primary sodium sampling pump in the Fast Flux Test Facility

On November 16, 1984 a leak was discovered in one of the Fast Flux Test Facility (FFTF) Primary Sodium Sampling System electromagnetic pumps. The leak was discovered in the course of routine cell entry to investigate a shorted trace heat element. The purpose of this paper is to describe the circumstances surrounding the occurrence of the leak, the actions taken to replace the damaged pump and the additional steps which were necessary to return the plant to power. In addition, the processes involved in producing the leak are described briefly. The relative ease of recovery from this incident is indicative of the overall feasibility of the Liquid Metal Reactor (LMR) operational concept.
Date: November 8, 1985
Creator: Grygiel, M. L. & McCargar, C. G.
System: The UNT Digital Library
Design and testing of low capacitance, 80-kV source cables for MFTF sustaining neutral beam power supplies (open access)

Design and testing of low capacitance, 80-kV source cables for MFTF sustaining neutral beam power supplies

In this paper we summarize characteristics of several cable configurations and consider one design in detail, which consists of twelve, 250 MCM arc cables, ten 4/0 filament cables, and accel, gradient grid, control, and instrumentation cables within a circular split Al pipe. The pipe is air insulated from an outer 24-in. x 24-in. steel duct by utility pin insulators. Varying run lengths require adjustment of the arc inductance by variation of cross sectional cable position. Equilibrium heat transfer analysis indicates the pulse-off time for source conditioning must be somewhat greater than 60 s to keep conductor temperatures below 90/sup 0/C. The results of a high voltage test of a model cable are presented.
Date: November 8, 1979
Creator: Mayhall, D. J. & Shimer, D. W.
System: The UNT Digital Library
Supervisory Control and Diagnostics System Distributed Operating System (open access)

Supervisory Control and Diagnostics System Distributed Operating System

This paper contains a description of the Supervisory Control and Diagnostics System (SCDS) Distributed Operating System. The SCDS consists of nine 32-bit minicomputers with shared memory. The system's main purpose is to control a large Mirror Fusion Test Facility (MFTF).
Date: November 8, 1979
Creator: McGoldrick, P.R.
System: The UNT Digital Library
Potential contribution of solar energy in the Northwest (open access)

Potential contribution of solar energy in the Northwest

Estimates on the ability of solar energy to supply US energy needs vary from 0 to 25%. It is generally thought that solar can supply as much as we want it to up to 25% in the Northwest by the year 2000 providing an all-out effort is applied now to develop solar energy. The factors affecting the extent of solar utilization are discussed; they are more institutional (inertia, experience, legal, social) than technological or economical. Because of its climate, unique power system, and amount of sunshine, the Northwest is one of the best places in the US for solar energy utilization. Solar energy used in the Northwest is more likely to meet needs that would otherwise be met by new thermal electric plants than is the case in most places.
Date: November 8, 1978
Creator: Drumheller, K.
System: The UNT Digital Library
Cryogenic Aspects of the Mirror Fusion Test Facility (open access)

Cryogenic Aspects of the Mirror Fusion Test Facility

This paper covers the design and construction of the MFTF cryogenic system and a description of the operating procedures throughout the many functional modes. The coils and the cryopanels for maintaining the high vacuum environment weigh 417,000 kg (920,000 lb) and must be cooled from room temperature to 4.5 k. The cryogenic system for MFTF consists of a closed-loop helium system with a 3000-W helium refrigerator that uses gas-bearing expansion turbines and oil-flooded screw compressors. In addition, liquid helium storage facilities have adequate capacity for standby operation, and a complete helium-purification plant is capable of processing 17 m/sup 3//min (600 scfm). An open-loop liquid nitrogen system (with provision for later addition of a nitrogen recondenser) provides the required refrigeration for the radiation shields that must be maintained at 85 K.
Date: November 8, 1979
Creator: Sterbentz, W. H. & Nelson, R. L.
System: The UNT Digital Library
Mirror fusion test facility plasma diagnostics system (open access)

Mirror fusion test facility plasma diagnostics system

During the past 25 years, experiments with several magnetic mirror machines were performed as part of the Magnetic Fusion Energy (MFE) Program at LLL. The latest MFE experiment, the Mirror Fusion Test Facility (MFTF), builds on the advances of earlier machines in initiating, stabilizing, heating, and sustaining plasmas formed with deuterium. The goals of this machine are to increase ion and electron temperatures and show a corresponding increase in containment time, to test theoretical scaling laws of plasma instabilities with increased physical dimensions, and to sustain high-beta plasmas for times that are long compared to the energy containment time. This paper describes the diagnostic system being developed to characterize these plasma parameters.
Date: November 8, 1979
Creator: Thomas, S.R. Jr., Coffield, F.E.; Davis, G.E. & Felker, B.
System: The UNT Digital Library
Division of Materials Science (DMS) meeting presentation (open access)

Division of Materials Science (DMS) meeting presentation

Materials preparation techniques are listed. Materials preparation capabilities are discussed for making BeF/sub 2/ glasses and other materials. Materials characterization techniques are listed. (DLC)
Date: November 8, 1982
Creator: Cline, C. F. & Weber, M. J.
System: The UNT Digital Library
Atomic vapor laser isotope separation (open access)

Atomic vapor laser isotope separation

Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements.
Date: November 8, 1985
Creator: Stern, R.C. & Paisner, J.A.
System: The UNT Digital Library
Probability Density Function for Waves Propagating in a Straight PEC Rough Wall Tunnel (open access)

Probability Density Function for Waves Propagating in a Straight PEC Rough Wall Tunnel

The probability density function for wave propagating in a straight perfect electrical conductor (PEC) rough wall tunnel is deduced from the mathematical models of the random electromagnetic fields. The field propagating in caves or tunnels is a complex-valued Gaussian random processing by the Central Limit Theorem. The probability density function for single modal field amplitude in such structure is Ricean. Since both expected value and standard deviation of this field depend only on radial position, the probability density function, which gives what is the power distribution, is a radially dependent function. The radio channel places fundamental limitations on the performance of wireless communication systems in tunnels and caves. The transmission path between the transmitter and receiver can vary from a simple direct line of sight to one that is severely obstructed by rough walls and corners. Unlike wired channels that are stationary and predictable, radio channels can be extremely random and difficult to analyze. In fact, modeling the radio channel has historically been one of the more challenging parts of any radio system design; this is often done using statistical methods. In this contribution, we present the most important statistic property, the field probability density function, of wave propagating in …
Date: November 8, 2004
Creator: Pao, H
System: The UNT Digital Library
Bioinspired Molecular Co-Catalysts Bonded to a Silicon Photocathode for Solar Hydrogen Evolution (open access)

Bioinspired Molecular Co-Catalysts Bonded to a Silicon Photocathode for Solar Hydrogen Evolution

The production of fuels from sunlight represents one of the main challenges in the development of a sustainable energy system. Hydrogen is the simplest fuel to produce and although platinum and other noble metals are efficient catalysts for photoelectrochemical hydrogen evolution earth-abundant alternatives are needed for large-scale use. We show that bioinspired molecular clusters based on molybdenum and sulphur evolve hydrogen at rates comparable to that of platinum. The incomplete cubane-like clusters (Mo{sub 3}S{sub 4}) efficiently catalyse the evolution of hydrogen when coupled to a p-type Si semiconductor that harvests red photons in the solar spectrum. The current densities at the reversible potential match the requirement of a photoelectrochemical hydrogen production system with a solar-to-hydrogen efficiency in excess of 10% (ref. 16). The experimental observations are supported by density functional theory calculations of the Mo{sub 3}S{sub 4} clusters adsorbed on the hydrogen-terminated Si(100) surface, providing insights into the nature of the active site.
Date: November 8, 2011
Creator: Hou, Yidong
System: The UNT Digital Library
DEVELOPMENT AND DEPLOYMENT OF THE MOBILE ARM RETRIEVAL SYSTEM (MARS) - 12187 (open access)

DEVELOPMENT AND DEPLOYMENT OF THE MOBILE ARM RETRIEVAL SYSTEM (MARS) - 12187

Washington River Protection Solutions (WRPS) is developing and deploying Mobile Arm Retrieval System (MARS) technologies solutions to support retrieval of radioactive and chemical waste from underground single shell storage tanks (SST) located at the Hanford Site, which is near Richland, Washington. WRPS has developed the MARS using a standardized platform that is capable of deploying multiple retrieval technologies. To date, WRPS, working with their mentor-protege company, Columbia Energy and Environmental Services (CEES), has developed two retrieval mechanisms, MARS-Sluicing (MARS-S) and MARS-Vacuum (MARS-V). MARS-S uses pressurized fluids routed through spray nozzles to mobilize waste materials to a centrally located slurry pump (deployed in 2011). MARS-V uses pressurized fluids routed through an eductor nozzle. The eductor nozzle allows a vacuum to be drawn on the waste materials. The vacuum allows the waste materials to be moved to an in-tank vessel, then extracted from the SST and subsequently pumped to newer and safer double shell tanks (DST) for storage until the waste is treated for disposal. The MARS-S system is targeted for sound SSTs (i.e., non leaking tanks). The MARS-V is targeted for assumed leaking tanks or those tanks that are of questionable integrity. Both versions of MARS are beinglhave been developed in …
Date: November 8, 2011
Creator: CA, BURKE; MR, LANDON & CE, HANSON
System: The UNT Digital Library