Physical Sciences and Mathematics | Open Access Articles

Utah Fire Amendment: Environmental Assessment, Pam Gardiner

Elusive Documents

No abstract provided.

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Value Engineering: Final Report- Bear River Migratory Bird Refuge Headquarters And Education Complex, U.S. Bureau Of Reclamation

Elusive Documents

No abstract provided.

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Effect Of Daily Fluctuations From Flaming Gorge Dam On Ice Processes In The Green River, John W. Hayse, Steven F. Daly, Andrew Tuthill, Richard A. Valdez, Bryan Cowdell, Gary Burton

Elusive Documents

No abstract provided.

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Utah Stream Team Appendices, John Geiger, Nancy Mesner

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No abstract provided.

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Group Invariant Solutions Without Transversality, Ian M. Anderson, Mark E. Fels, Charles G. Torre

All Physics Faculty Publications

We present a generalization of Lie's method for finding the group invariant solutions to a system of partial differential equations. Our generalization relaxes the standard transversality assumption and encompasses the common situation where the reduced differential equations for the group invariant solutions involve both fewer dependent and independent variables. The theoretical basis for our method is provided by a general existence theorem for the invariant sections, both local and global, of a bundle on which a finite dimensional Lie group acts. A simple and natural extension of our characterization of invariant sections leads to an intrinsic characterization of the reduced …

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Actions For Biconformal Matter, Andre Wehner, James Thomas Wheeler

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We extend 2n-dim biconformal gauge theory by including Lorentz-scalar matter fields of arbitrary conformal weight. For a massless scalar field of conformal weight zero in a torsion-free biconformal geometry, the solution is determined by the Einstein equation on an n-dim submanifold, with the stress-energy tensor of the scalar field as source. The matter field satisfies the n-dim Klein-Gordon equation.

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Record Of Decision Based On The Final Environmental Impact Statement For The South Manti Timber Salvage, United States Forest Service

Record of Decisions (UT)

This project was initiated in response to epidemic spruce beetle (Dendroctonus rufipennis) activity across the South Manti landscape. The Final Environmental Impact Statement (FEIS) summarizes potential direct, indirect, and cumulative effects of corresponding site-specific forest management alternatives on portions of the Ferron-Price and Sanpete Ranger Districts of the Manti-La Sal National Forest.

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South Manti Timber Salvage Final Environmental Impact Statement, United States Forest Service

Final environmental Impact Statements (UT)

This project was initiated in response to epidemic spruce beetle (Dendroctonus rufipennis) activity across approximately 24,597 acres of National Forest System lands within the southern portion of the Wasatch Plateau (Townships 19, 20, and 21 South; Range 4 East; SLM). The South Manti project area is located on the Manti-La Sal National Forest approximately 45 miles southwest of Price, Utah.

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Modeling The Evolution Of Meso-Scale Ionospheric Irregularities At High Latitudes, Jan Josef Sojka, L. Zhu, M. David, Robert W. Schunk

All Physics Faculty Publications

The modeling of ionospheric plasma density irregularities (ΔN/N) is a necessary first step towards forecasting ionospheric scintillation effects. This modeling challenge is difficult not only because the linear‐nonlinear saturation levels of instabilities are not completely understood but also because ΔN/N often evolves on time scales which are long compared to the characteristic time constants of the instability drivers. In this study, the linear 1‐D gradient drift instability (GDI) is used in a high latitude simulation of ΔN/N evolution. For the first time snapshots (maps) of ΔN/N are presented demonstrating that it is possible to use …

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Model Study Of Ionospheric Dynamics During A Substorm, Lie Zhu, Robert W. Schunk, Jan Josef Sojka, Michael David

All Physics Faculty Publications

A global substorm electrodynamic model and a global ionospheric model were coupled in order to study ionospheric dynamics during substorms, with the focus on small-scale substorm electrodynamic and plasma structures. The simulation results show that in the expansion phase, structured precipitation and channeled field-aligned currents quickly develop in the substorm onset region. The Hall and Pedersen conductance ratio in the region increases significantly, and the magnetospheric field-aligned currents are mainly closed by highly structured Hall currents. Correspondingly, the plasma in the ionosphere also undergoes significant changes during a substorm and is highly structured in both the horizontal and vertical directions. …

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Measurements Of Electronic Properties Of Conducting Spacecraft Materials With Application To The Modeling Of Spacecraft Charging, W. Y. Chang, John R. Dennison, Parker Judd

All Physics Faculty Publications

This paper describes the results of the first stage of this project, measurements of the electronic properties of conducting spacecraft materials. We begin with a description of the required measurements and specifics of the experimental methods used. A complete list of the conducting materials studied, justification of their selection for study, and a summary of the important results of the measurements is presented. This is followed by detailed measurements and analysis for one representative conductor, namely polycrystalline Au. We end with a description of incorporation of these measurements into the NASCAP database.

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Using Binary Star Observations To Bound The Mass Of The Graviton, Shane L. Larson, William A. Hiscock

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Interacting white dwarf binary star systems, including helium cataclysmic variable (HeCV) systems, are expected to be strong sources of gravitational radiation, and should be detectable by proposed space-based laser interferometer gravitational wave observatories such as LISA. Several HeCV star systems are presently known and can be studied optically, which will allow electromagnetic and gravitational wave observations to be correlated. Comparisons of the phases of a gravitational wave signal and the orbital light curve from an interacting binary white dwarf star system can be used to bound the mass of the graviton. Observations of typical HeCV systems by LISA could potentially …

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A Comprehensive Study Of Dielectric-Conductor Junctions In Low Density Plasmas, B. V. Vayner, J. T. Galofaro, D. C. Ferguson, W. A. De Groot, C. D. Thomson, John R. Dennison, R. E. Davies

All Physics Faculty Publications

In this paper, results are presented of an experimental and theoretical study of snapover, glow discharge, and arc phenomena for different materials immersed in argon or xenon plasmas. The effect of snapover is investigated for several metal-dielectric junctions: copper-teflon, copper-Kapton, copper-glass, aluminum-teflon, aluminum-Kapton, steel-teflon, anodized aluminum with pinholes, and copper-ceramics. I-V curves are measured, and snapover inception voltages, essential parameters (increase in current and collection area due to secondary electrons), and glow discharge inception thresholds are determined. Optical spectra are obtained for glow discharges in both argon and xenon plasmas. These spectra provide information regarding atomic species entrapped in the …

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Measurement Of Silicon Surface Recombination Velocity Using Ultrafast Pump-Probe Reflectivityin The Near Infrared, A. J. Sabbah, D. Mark Riffe

All Physics Faculty Publications

We demonstrate that ultrafast pump–probe reflectivity measurements from bulk Si samples using a Ti:sapphire femtosecond oscillator (λ=800 nm) can be used to measure the Si surface recombination velocity. The technique is sensitive to recombination velocities greater than ∼10⁴ cm s⁻¹

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Extended Conformal Symmetry, James Thomas Wheeler

All Physics Faculty Publications

We show that the grading of fields by conformal weight, when built into the initial group symmetry, provides a discrete, non-central conformal extension of any group containing dilatations. We find a faithful vector representation of the extended conformal group and show that it has a scale-invariant scalar product and satisfies a closed commutator algebra. The commutator algebra contains the infinite Heisenberg and Virasoro algebras. In contrast to the classical treatment of scale invariance, covariant derivatives and gauge transformations automatically incorporate the correct conformal weights when the extended symmetry is gauged.

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Inception Of Snapover And Gas Induced Glow Discharges, J. T. Galofaro, B. V. Vayner, D. C. Ferguson, W. A. Degroot, C. D. Thomson, John R. Dennison, R. E. Davies

All Physics Faculty Publications

Ground based experiments of the snapover phenomenon were conducted in the large vertical simulation chamber at the Glenn Research Center (GRC) Plasma Interaction Facility (PIF). Two Penning sources provided both argon and xenon plasmas for the experiments. The sources were used to simulate a variety of ionospheric densities pertaining to a spacecraft in a Low Earth Orbital (LEO) environment. Secondary electron emission is believed responsible for dielectric surface charging, and all subsequent snapover phenomena observed. Voltage sweeps of conductor potentials versus collected current were recorded in order to examine the specific charging history of each sample. The average time constant …

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Effects Of Evolving Surface Contamination On Spacecraft Charging, W. Y. Chang, John R. Dennison, Jason Kite, R. E. Davies

All Physics Faculty Publications

The effects of evolving surface contamination on spacecraft charging have been investigated through (i) ground-based measurements of the change in electron emission properties of a conducting surface undergoing contamination and (ii) modeling of the charging of such surfaces using the NASCAP code. Specifically, we studied a Au surface as adsorbed species were removed and a very thin disordered carbon film was deposited as a result of exposure to an intense, normal incidence electron beam. As a result of this contamination, we found an ~50% decrease in secondary electron yield and an ~20% reduction in backscattered yield. The type and rates …

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Sensitivity Curves For Spaceborne Gravitational Wave Interferometers, Shane L. Larson, William A. Hiscock, Ronald W. Hellings

All Physics Faculty Publications

To determine whether particular sources of gravitational radiation will be detectable by a specific gravitational wave detector, it is necessary to know the sensitivity limits of the instrument. These instrumental sensitivities are often depicted (after averaging over source position and polarization) by graphing the minimal values of the gravitational wave amplitude detectable by the instrument versus the frequency of the gravitational wave. This paper describes in detail how to compute such a sensitivity curve given a set of specifications for a spaceborne laser interferometer gravitational wave observatory. Minor errors in the prior literature are corrected, and the first (mostly) analytic …

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Investigation Of The First Snapover Of Positively Biased Conductors In A Plasma, C. D. Thomson, John R. Dennison, R. E. Davies, D. C. Ferguson, J. T. Galafaro, B. V. Vayner

All Physics Faculty Publications

We describe a systematic experimental investigation of the phenomenon termed "snapover." In snapover, the current collected by a positively biased conductor, surrounded by a dielectric and immersed in a plasma, increases dramatically when the conductor potential is raised above some threshold value. The phenomenon is particularly relevant to the case of high-voltage solar arrays in Earth orbit. Our experiments examined the importance of conducting material, insulating material, size and shape of the conductor, sample history, biasing rate, and condition of the dielectric surface (contamination and smoothness) to the onset potential and current jump. In addition to a primary snapover occurring …

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Measurements Of Electronic Properties Of Conducting Spacecraft Materials With Application To The Modeling Of Spacecraft Charging, W. Y. Chang, Jr Dennison, Parker Judd

Conference Proceedings

Many spacecraft system anomalies and component failures are known to result from spacecraft charging which is due to the bombardments of spacecraft by energetic electrons, ions, and photons in natural space surrounding [Hastings and Garrett, 1996; Bedingfield et al., 1996; Leach et al., 1995]. To assist spacecraft designers in accommodating and mitigating the harmful charging effects on spacecraft, NASA has developed an extensive set of engineering tools to predict the extent of charging in various spacecraft environments (for example, NASCAP/LEO, NASCAP/GEO, and POLAR) [Mandell et al., 1993]. However, current NASCAP databases lack electronic properties …

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Inception Of Snapover And Gas Induced Glow Discharges, J. T. Galofaro, B V. Vayner, D C. Ferguson, C D. Thomson, Jr Dennison, R E. Davies

Conference Proceedings

Ground based experiments of the snapover phenomenon were conducted in the large vertical simulation chamber at the Glenn Research Center (GRC) Plasma Interaction Facility (PIF). Two Penning sources provided both argon and xenon plasmas for the experiments. The sources were used to simulate a variety of ionospheric densities pertaining to a spacecraft in a Low Earth Orbital (LEO) environment^1–4. Secondary electron emission is believed responsible for dielectric surface charging, and all subsequent snapover phenomena observed^2,5. Voltage sweeps of conductor potentials versus collected current were recorded in order to examine the specific charging history of each sample. …

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Inception Of Snapover And Gas Induced Glow Discharges, J. T. Galofaro, B V. Vayner, W A. Degroot, D C. Ferguson, C D. Thomson, Jr Dennison, R E. Davies

Conference Proceedings

Ground based experiments of the snapover phenomenon were conducted in the large vertical simulation chamber at the Glenn Research Center (GRC) Plasma Interaction Facility (PIF). Two Penning sources provided both argon and xenon plasmas for the experiments. The sources were used to simulate a variety of ionospheric densities pertaining to a spacecraft in a Low Earth Orbital (LEO) environment^1-4. Secondary electron emission is believed responsible for dielectric surface charging, and all subsequent snapover phenomena observed^2,5. Voltage sweeps of conductor potentials versus collected current were recorded in order to examine the specific charging history of each sample. …

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Evolution Of Secondary Electron Emission Characteristics Of Spacecraft Surfaces: Importance To Spacecraft Charging, R. E. Davies, Jr Dennison

Journal Articles

Secondary electron emission (SEE) plays a key role in spacecraft charging [Garrett, 1981; Frooninckx and Sojka, 1992] . As a result, spacecraft charging codes require knowledge of the SEE characteristics of various materials in order to predict vehicle potentials in various orbital environments [Katz, et. al., 1986]. Because SEE is a surface phenomenon, occurring in the first few atomic layers of a material, the SEE characteristics of a given surface are extremely sensitive to changes in surface condition—e.g., the addition or removal of surface contaminants, or changes in surface morphology. That spacecraft surfaces …

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Final Environmental Impact Statement Cabinet Gorge (No. 2058-014) And Noxon Rapids (No. 2075-014) Hydroelectric Projects Idaho And Montana, United States Department Of Energy Federal Energy Regulatory Commission

Final Environmental Impact Statements (ID)

On February 17, 1999, Avista Corporation filed an application for relicense of the existing 231-megawatt Cabinet Gorge and 466-megawatt Noxon Rapids projects located on the Clark Fork River in Idaho and Montana. Avista Corporation's proposed relicensing alternative for these two projects includes a comprehensive settlement agreement that was developed through the use of the Commission's Alternative Licensing Procedures and a collaborative approach during prefiling consultation. As part of the settlement agreement, Avista Corporation is proposing to use an adaptive management approach to implement the various protection, mitigation, and enhancement measures. The staff's recommendation is to relicense the project as proposed …

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Final Environmental Impact Statement Brown Creek Timber Sale, United States Forest Service

Final Environmental Impact Statements (ID)

This Final Environmental Impact Statement (FEIS) documents the analysis of three alternatives for the Brown Creek Timber Sale on the New Meadows Ranger District of the Payette National Forest. The Brown Creek project area is located on the east side of the New Meadows Ranger district, just south of Bally Mountain and just west of Granite Mountain.

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Environmental Assessment Wild Horse Gathering For The Fifteenmile Wild Horse Herd Management Area, United States Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

The purpose for management of wild, free roaming horses is to comply with law and policy pertaining to wild, free roaming horses on public lands. The policy of the BLM addresses a range of topics including establishment and maintenance of Appropriate Management Levels (AMLs) in Herd Managment Areas (HMAs) in a humane, safe, efficient, and environmentally sound manner.

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Provisional Report: Radionuclides And Pu Toxicity, University Of Utah

All U.S. Government Documents (Utah Regional Depository)

No abstract provided.

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Winter Use Plans Final Environmental Impact Statement Summary For The Yellowstone And Grand Teton National Parks And John D. Rockefeller, Jr., Memorial Parkway, United States, Department Of The Interior, National Forest Service

Final Environmental Impact Statements (WY)

This document presents and analyzes seven alternatives for winter use management in Yellowstone National Park (YNP), Grand Teton National Park (GTNP), and the John D. Rockefeller, Jr., Memorial Parkway (the Parkway). YNP, encompassing 2.22 million acres, and GTNP, comprising 310,000 acres, form the core of the Greater Yellowstone Ecosystem, described as the last large, nearly intact ecosystem in the northern temperate zone. The approved plan will serve as a management plan for the three national parks.

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Winter Use Plans Final Environmental Impact Statement Volume Ii For The Yellowstone And Grand Teton National Parks And John D. Rockefeller, Jr., Memorial Parkway, United States, Department Of The Interior, National Park Service

Final Environmental Impact Statements (WY)

By special agreement as provided under 40 CFR § 1501.6 and § 1508.5, the National Park Service (NPS), the lead agency in this Environmental Impact Statement (EIS), has collaborated with nine cooperating agencies in the EIS process: the U.S. Forest Service; the States of Idaho, Montana, and Wyoming; and the Counties of Gallatin and Park, Montana, Park and Teton, Wyoming, and Fremont, Idaho. The Council on Environmental Quality (CEQ) regulations for implementing National Environmental Policy Act (NEPA) define a cooperating agency as any agency that has jurisdiction by law or, in this case, special expertise for proposals covered by NEPA. …

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Environmental Assessment And Finding Of No Significant Impact For The Modified Jonah Field Ii Natural Gas Project, Sublette County, Wyoming, United States Department Of The Interior, Bureau Of Land Management

Environmental Assessments (WY)

Both the Pinedale Resource Area Resource Management Plan and the Green River Resource Area Resource Management Plan provide for the use of these public lands for oil and natural gas development. The Proposed Action would be in conformance with these land use plans, and no amendments to the RMPs would be necessary to implement the Proposed Action.

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Full-Text Articles in Physical Sciences and Mathematics

Utah Fire Amendment: Environmental Assessment, Pam Gardiner

Elusive Documents

Value Engineering: Final Report- Bear River Migratory Bird Refuge Headquarters And Education Complex, U.S. Bureau Of Reclamation

Elusive Documents

Effect Of Daily Fluctuations From Flaming Gorge Dam On Ice Processes In The Green River, John W. Hayse, Steven F. Daly, Andrew Tuthill, Richard A. Valdez, Bryan Cowdell, Gary Burton

Elusive Documents

Utah Stream Team Appendices, John Geiger, Nancy Mesner

All Archived Publications

Group Invariant Solutions Without Transversality, Ian M. Anderson, Mark E. Fels, Charles G. Torre

All Physics Faculty Publications

Actions For Biconformal Matter, Andre Wehner, James Thomas Wheeler

All Physics Faculty Publications

Record Of Decision Based On The Final Environmental Impact Statement For The South Manti Timber Salvage, United States Forest Service

Record of Decisions (UT)

South Manti Timber Salvage Final Environmental Impact Statement, United States Forest Service

Final environmental Impact Statements (UT)

Modeling The Evolution Of Meso-Scale Ionospheric Irregularities At High Latitudes, Jan Josef Sojka, L. Zhu, M. David, Robert W. Schunk

All Physics Faculty Publications

Model Study Of Ionospheric Dynamics During A Substorm, Lie Zhu, Robert W. Schunk, Jan Josef Sojka, Michael David

All Physics Faculty Publications

Measurements Of Electronic Properties Of Conducting Spacecraft Materials With Application To The Modeling Of Spacecraft Charging, W. Y. Chang, John R. Dennison, Parker Judd

All Physics Faculty Publications

Using Binary Star Observations To Bound The Mass Of The Graviton, Shane L. Larson, William A. Hiscock

All Physics Faculty Publications

A Comprehensive Study Of Dielectric-Conductor Junctions In Low Density Plasmas, B. V. Vayner, J. T. Galofaro, D. C. Ferguson, W. A. De Groot, C. D. Thomson, John R. Dennison, R. E. Davies

All Physics Faculty Publications

Measurement Of Silicon Surface Recombination Velocity Using Ultrafast Pump-Probe Reflectivityin The Near Infrared, A. J. Sabbah, D. Mark Riffe

All Physics Faculty Publications

Extended Conformal Symmetry, James Thomas Wheeler

All Physics Faculty Publications

Inception Of Snapover And Gas Induced Glow Discharges, J. T. Galofaro, B. V. Vayner, D. C. Ferguson, W. A. Degroot, C. D. Thomson, John R. Dennison, R. E. Davies

All Physics Faculty Publications

Effects Of Evolving Surface Contamination On Spacecraft Charging, W. Y. Chang, John R. Dennison, Jason Kite, R. E. Davies

All Physics Faculty Publications

Sensitivity Curves For Spaceborne Gravitational Wave Interferometers, Shane L. Larson, William A. Hiscock, Ronald W. Hellings

All Physics Faculty Publications

Investigation Of The First Snapover Of Positively Biased Conductors In A Plasma, C. D. Thomson, John R. Dennison, R. E. Davies, D. C. Ferguson, J. T. Galafaro, B. V. Vayner

All Physics Faculty Publications

Measurements Of Electronic Properties Of Conducting Spacecraft Materials With Application To The Modeling Of Spacecraft Charging, W. Y. Chang, Jr Dennison, Parker Judd

Conference Proceedings

Inception Of Snapover And Gas Induced Glow Discharges, J. T. Galofaro, B V. Vayner, D C. Ferguson, C D. Thomson, Jr Dennison, R E. Davies

Conference Proceedings

Inception Of Snapover And Gas Induced Glow Discharges, J. T. Galofaro, B V. Vayner, W A. Degroot, D C. Ferguson, C D. Thomson, Jr Dennison, R E. Davies

Conference Proceedings

Evolution Of Secondary Electron Emission Characteristics Of Spacecraft Surfaces: Importance To Spacecraft Charging, R. E. Davies, Jr Dennison

Journal Articles

Final Environmental Impact Statement Cabinet Gorge (No. 2058-014) And Noxon Rapids (No. 2075-014) Hydroelectric Projects Idaho And Montana, United States Department Of Energy Federal Energy Regulatory Commission

Final Environmental Impact Statements (ID)

Final Environmental Impact Statement Brown Creek Timber Sale, United States Forest Service

Final Environmental Impact Statements (ID)

Environmental Assessment Wild Horse Gathering For The Fifteenmile Wild Horse Herd Management Area, United States Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

Provisional Report: Radionuclides And Pu Toxicity, University Of Utah

All U.S. Government Documents (Utah Regional Depository)

Winter Use Plans Final Environmental Impact Statement Summary For The Yellowstone And Grand Teton National Parks And John D. Rockefeller, Jr., Memorial Parkway, United States, Department Of The Interior, National Forest Service

Final Environmental Impact Statements (WY)

Winter Use Plans Final Environmental Impact Statement Volume Ii For The Yellowstone And Grand Teton National Parks And John D. Rockefeller, Jr., Memorial Parkway, United States, Department Of The Interior, National Park Service

Final Environmental Impact Statements (WY)

Environmental Assessment And Finding Of No Significant Impact For The Modified Jonah Field Ii Natural Gas Project, Sublette County, Wyoming, United States Department Of The Interior, Bureau Of Land Management

Environmental Assessments (WY)