Physical Sciences and Mathematics Commons^™

Electric Field Induced Hopping Conductivity And Polarization In Hytrel, Steve Hart

Senior Theses and Projects

The focus of my 4900 research project is centered on the conductivity of Hytrel, a complex, newly developed block co-polymer. I first began to study Hytrel during the summer of 2006, as part of the USU College of Science Mini-Grant program¹. My general objective was to study the relationship between the resistivity of Hytrel and hopping conductivity. Hopping conductivity is a theory of electron transport for nonconducting solids, originally developed for amorphous semiconductors^2,3. The theory will be examined in greater detail later in this document. While studying this relationship last summer, I noticed an unusual phenomenon …

Gauging Newton’S Law, James Thomas Wheeler

All Physics Faculty Publications

We derive both Lagrangian and Hamiltonian mechanics as gauge theories of Newtonian mechanics. Systematic development of the distinct symmetries of dynamics and measurement suggest that gauge theory may be motivated as a reconciliation of dynamics with measurement. Applying this principle to Newton's law with the simplest measurement theory leads to Lagrangian mechanics, while use of conformal measurement theory leads to Hamiltonian mechanics.PACS Nos.: 45.20.Jj, 11.25.Hf, 45.10.–b [ABSTRACT FROM AUTHOR]

The Green Beam—Lidar Investigations Of The Mesosphere, Vincent B. Wickwar

Presentations

No abstract provided.

A Very Active Sprite-Producing Storm Observed Over Argentina, J. N. Thomas, Michael J. Taylor, Pierre-Dominique Pautet, T. Berkey, N. N. Solorzano, R. H. Holzworth, M. P. Mccarthy, M. Kokorowski, F. Sao Sabbas, O. Pinto Jr., S. A. Cummer, N. Jaugey, J. Li, N. J. Schuch

All Physics Faculty Publications

During the night of 22–23 February 2006, more than 400 middle- atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, …

Doppler Ducting Of Short-Period Waves By Mid-Latitude Tidal Wind Structure, J. B. Snively, V. P. Pasko, Michael J. Taylor, W. K. Hocking

All Physics Faculty Publications

Multiwavelength airglow image data depicting a short-period (4.9 min) atmospheric gravity wave characterized by a sharp leading front have been analyzed together with synoptic meteor radar wind data recorded simultaneously from Bear Lake Observatory, Utah (41.6N, 111.6W). The wind data suggest the presence of a semidiurnal tide with horizontal winds peaking at around 60 m/s along the SSE direction of motion (170 from north) of this short-period wave. It was found that the gravity wave was most probably ducted because of the Doppler shift imposed by this wind structure. A marked 180 phase shift was observed between the near-infrared OH …

On The Use Of Simultaneous Measurements Of Oh And O2 Emissions To Investigate Wave Growth And Dissipation, A. Taori, A. Guharay, Michael J. Taylor

All Physics Faculty Publications

Simultaneous measurements of mesospheric OH (6–2) Meinel and O2 (0–1) Atmospheric band emissions from a low-latitude station, Maui, Hawaii (20.8 N, 156.2 W) are utilized to study the wave characteristics and associated processes. Deduced temperatures show large variability in both OH and O2 data. The seasonal variability in the temperature shows a well-defined, semiannual type of oscillation, which are comparable to the ground-based rocket sounding data. The “Wave Growth Factor”, a ratio of normalized perturbation amplitude in O2 to the OH temperature variability, is estimated for principal as well as residual smaller period components of the nocturnal variability. It is …

Lake Mead Complex Final Gather Plan: Environmental Assessment, U.S. Department Of The Interior, Bureau Of Land Management

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

This Environmental Assessment (EA) has been prepared by the Bureau of Land Management (BLM) Las Vegas Field Office (LVFO) to analyze the environmental effects of a gather to remove approximately 195 resident wild burros from National Park Service-administered lands adjacent to the El Dorado Mountains, Gold Butte and Muddy Mountains Herd Management Areas (HMAs) within the Lake Mead Complex (LMC) in March 2007. The LMC is located in southern Nevada in Clark County. The BLM Las Vegas Field Office and National Park Service coordinate management activities for wild burros on these public lands within their individual administrative responsibilities through a …

Scoping Report For The Glen Canyon Dam Long-Term Experimental Plan Environmental Impact Statement, U.S. Department Of The Interior, Bureau Of Reclamation

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

This report summarizes the issues raised during the initial scoping process for the Bureau of Reclamation's Long-term Experimental Plan for Glen Canyon Dam Operations and Other Management Actions Environmental Impact Statement (EIS). This report describes the initial scoping process and presents the schedule, describes the scoping meetings, summarizes comments submitted by the public, and provides an overview of the relevant issues that Reclamation anticipates will be analyzed in the EIS.

Scoping is defined by the regulations implementing the National Environmental Policy Act (NEPA) as the process whereby lead agencies solicit input from the public on what the issues and alternatives …

Investigation Of A "Wall" Wave Event, F. Li, G. R. Swenson, A. Z. Liu, Michael J. Taylor, Y. Zhao

All Physics Faculty Publications

A bright airglow event was observed at Maui, Hawaii, on the night of 11–12 August 2004 with multiple instruments including a Na wind/temperature lidar, an airglow imager, and a mesospheric temperature mapper. The characteristics of this event were investigated with measurements from these instruments. Analysis showed that this event was caused by a large-amplitude, upward-propagating gravity wave with a period of about 4–5 hours and a vertical wavelength of about 20 km, i.e., a ‘‘wall’’ wave. This wall wave induced dramatic changes in temperature (60 K), airglow intensity (doubled in the OH and tripled in the O2 emissions), and Na …

Kerr-Mcgee's Bonanza Area Environmental Assessment And Biological Assessment, U.S. Department Of The Interior, Bureau Of Land Management

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

No abstract provided.

Estimation Of Dry Deposition Of Atmospheric Mercury In Nevada By Direct And Indirect Methods, Seth N. Lyman, Mae Sexauer Gustin, Eric M. Prestbo, Frank J. Marsik

USU Uintah Basin Faculty Publications

Atmospheric models and limited measurements indicate that dry deposition of atmospheric mercury is an important process by which mercury is input to ecosystems. To begin to fill the measurement data gap, multiple methods were used simultaneously during seasonal campaigns conducted in 2005 and 2006 to estimate dry deposition of atmospheric mercury at two Mercury Deposition Network (MDN) sites in rural Nevada and in Reno, Nevada. Gaseous elemental mercury (Hg0), reactive gaseous mercury (RGM), and particulate-bound mercury (Hgp) concentrations were measured using Tekran 2537A/1130/1135 systems. These speciated measurements were combined with on-site meteorological measurements to estimate depositional fluxes of RGM and …

Chemical And Dynamical Processes In The Mesospheric Emissive Layer. First Results Of Stereoscopic Observations, M. Faivre, G. Moreels, Pierre-Dominique Pautet, J. Clairemidi, F. Dumont, O. Lorin, F. Colas

Publications

[1] The mesospheric emissive layer is an efficient tracer of the dynamical processes propagating in the atmosphere at that level. CCD images in the near infrared taken from the ground at slant angles often reveal the existence of wavy fields. A series of such images has been transformed, using matrix operations, producing a downward satellite-type view that covers a circular area of radius ∼1000 km at the altitude of the layer. The Fourier characteristics of the wave system are measured using a Morlet-type wavelet generator function with horizontal wavelengths of mostly ∼20–40 km and 100–150 km and temporal periods of …

Capstone Mathematics And Technology: A Collection Of Mathematical Technology Enhanced Activities For Students And Teachers, Heidi Eastman

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The purpose of this project is to provide an introduction to how technology can be used in the mathematical classroom to enhance students' learning of mathematics, while at the same time leading students to a richer and deeper understanding of those mathematical concepts. The topics were selected based on their relevance to the Utah State Core Curriculum for middle and secondary mathematics courses. It was intended that each lesson plan would challenge a preservice mathematics educator to build relationships between different areas of mathematics and/or to create deeper understandings of specific mathematical concepts. At the same time many of the …

Damming Grand Canyon: The 1923 Usgs Colorado River Expedition, Diane E. Boyer, Robert H. Webb

All USU Press Publications

In 1923, America paid close attention, via special radio broadcasts, newspaper headlines, and cover stories in popular magazines, as a government party descended the Colorado to survey Grand Canyon. Fifty years after John Wesley Powell's journey, the canyon still had an aura of mystery and extreme danger. At one point, the party was thought lost in a flood. Something important besides adventure was going on. Led by Claude Birdseye and including colorful characters such as early river-runner Emery Kolb, popular writer Lewis Freeman, and hydraulic engineer Eugene La Rue, the expedition not only made the first accurate survey of the …

Discontinuities In Stream Nutrient Uptake Below Lakesin Mountain Drainage Networks, Michelle A. Baker

Michelle A. Baker

In many watersheds, lakes and streams are hydrologically linked in spatial patterns that influence material transport and retention. We hypothesized that lakes affect stream nutrient cycling via modifications to stream hydrogeomorphology, source‐waters, and biological communities. We tested this hypothesis in a lake district of the Sawtooth Mountains, Idaho. Uptake of NO3− and PO4−3 was compared among 25 reaches representing the following landscape positions: lake inlets and outlets, reaches >1‐km downstream from lakes, and reference reaches with no nearby lakes. We quantified landscape‐scale hydrographic and reach‐scale hydrogeomorphic, source‐water, and biological variables to characterize these landscape positions and analyze relationships to nutrient …

Paria View Rehabilitation Project Environmental Assessment, U.S. Department Of The Interior

Elusive Documents

No abstract provided.

Relative Role Of Understory And Overstory In Carbon And Nitrogen Cycling In A Southern Appalachian Spruce-Fir Forest, P. T. Moore, H. Van Miegroet, N. S. Nicholas

Watershed Sciences Faculty Publications

This study investigated aboveground pools and fluxes of biomass, carbon (C), and nitrogen (N) in the overstory and understory of a southern Appalachian red spruce (Picea rubens Sarg.) – Fraser fir (Abies fraseri (Pursh) Poir.) forest, following adelgid-induced fir mortality and spruce windthrow. Using fifty 20 m × 20 m plots, stratified by elevation (1700–1900 m), we estimated standing biomass and fluxes of all growth forms from periodic stand inventories (1998–2003), vegetation surveys, and existing or derived allometric equations. Total C and N pools and fluxes were calculated from plant- and tissue-specific C and N concentrations. Total aboveground biomass attained …

Soil Organic Carbon Dynamics Along A Climatic Gradient In A Southern Appalachian Spruce-Fir Forest, C. E. Tewksbury, H. Van Miegroet

Watershed Sciences Faculty Publications

A field study was conducted in a high-elevation spruce–fir (Picea rubens Sarg. – Abies fraseri (Pursh.) Poir) forest in the Great Smoky Mountains National Park to assess the effect of temperature on soil C storage and dynamics. In eight plots along an elevation gradient (1500–1900 m), we measured soil temperature, forest floor and mineral soil C, litter decomposition, soil respiration, and forest floor mean residence time. Mean annual soil temperature and annual degree-days above 5 °C were inversely correlated with elevation. Total soil C (166–241 Mg·ha–1) showed no trend with elevation, while forest floor C accumulation (16.3–35.9 Mg·ha–1) decreased significantly …

Electron-Induced Electron Yields Of Uncharged Insulating Materials, Ryan Carl Hoffmann, John R. Dennison, Jennifer Albretsen

All Physics Faculty Publications

This study presents electron-induced electron yield measurements from high-resistivity, high-yield materials to validate a model for the yield of uncharged insulators. These measurements are accomplished by using a low-fluence, pulsed incident electron beam and charge neutralization to minimize charge accumulation. Our measurements show large changes in total yield curves and yield decay curves, even for incident electron fluences of/mm2. We model the evolution of the yield as charge accumulates in the material in terms of electron re-capture based on the extended Chung-Everhart model of the electron emission spectrum. This model is used to explain anomalies measured in high yield ceramics, …

Triggering Threshold Spacecraft Charging With Changes In Electron Emission From Materials, John R. Dennison, R. C. Hoffmann, J. Abbott

All Physics Faculty Publications

Modest changes in spacecraft charging conditions can lead to abrupt changes in the spacecraft equilibrium, from small positive potentials to large negative potentials relative to the space plasma; this phenomenon is referred to as threshold charging. It is well known that temporal changes of the space plasma environment (electron plasma temperature or density) can cause threshold charging. Threshold charging can also result from by temporal changes in the juxtaposition of the spacecraft to the environment, including spacecraft orbit, orientation, and geometry. This study focuses on the effects of possible changes in electron emission properties of representative spacecraft materials. It is …

Dependence Of Resistivity In Low-Density Polyethylene On Space Environment Parameters, John R. Dennison, Jerilyn Brunson

All Physics Faculty Publications

The conductivity of high-resistivity polymer films is dependent on the magnitude of applied electric field, repeated electric field exposure, and sample temperature. A traditional constant voltage method was used, maintained under vacuum to more closely resemble the space environment. Both the strength of the applied voltage and the thickness of low-density polyethylene (LDPE) samples were varied to determine the electric field dependence of internal polarization and the leakage current most appropriate in calculating the resistivity. Repetition of same field strength measurements determined the influence of sample history and charging memory. Measuring the resistivity from cryogenic temperatures to well above the …

Yang-Mills Gravity In Biconformal Space, L. B. Anderson, James Thomas Wheeler

All Physics Faculty Publications

We write a gravity theory with Yang–Mills-type action using the biconformal gauging of the conformal group. We show that the resulting biconformal Yang–Mills gravity theories describe 4-dim, scale-invariant general relativity in the case of slowly changing fields. In addition, we systematically extend arbitrary 4-dim Yang–Mills theories to biconformal space, providing a new arena for studying flat-space Yang–Mills theories. By applying the biconformal extension to a 4-dim pure Yang–Mills theory with conformal symmetry, we establish a 1-1, onto mapping between a set of gravitational gauge theories and 4-dim, flat-space gauge theories.

Assessing Models For Ionospheric Weather Specifications Over Australia During The 2004 Climate And Weather Of The Sun-Earth-System (Cawses) Campaign, Jan Josef Sojka, D. C. Thompson, L. Scherliess, Robert W. Schunk, T. J. Harris

All Physics Faculty Publications

The Utah State University (USU) Global Assimilation of Ionospheric Measurements (GAIM) program is developing assimilation models to specify ionospheric weather. In this study the Gauss Markov Kalman Filter (GMKF) GAIM model was used. The period 20 March through 19 April 2004, which spanned the Climate and Weather of the Sun-Earth-System (CAWSES) first study period, has been extensively studied to validate the performance of the GAIM model. Although the USU-GAIM model has both regional and global capabilities and can assimilate data from a wide variety of ionospheric observations, for this study the GMKF model was run in a global mode using …

Dendroarchaeology Of The Salt Lake Tabernacle, Utah, Matthew F. Bekker, David M. Heath

Wasatch Dendroclimatology Research

We examined tree rings from Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) timbers in the Salt Lake Tabernacle, constructed from 1863–1867 in Salt Lake City, Utah. A seismic upgrade to the Tabernacle initiated in 2005 required the replacement of wooden timbers with steel beams. Our objectives were to 1) determine cutting dates for the timbers to identify logs that may have been salvaged from previous structures, and consequently would have greater historical significance, 2) identify the species and provenance of the timbers, and 3) develop a chronology that could extend or strengthen the existing tree-ring record for environmental and …

Ionospheric Challenges Of The International Polar Year, Jan Josef Sojka, Robert W. Schunk, Tony Van Eyken, John Kelly, Craig Heinselman, Mary Mccready

All Physics Faculty Publications

Fifty years ago, the first International Geophysical Year (lGY) generated a huge step function increase in observations of ionospheric variability associated with the almost continuous geomagnetic activity experienced during the largest solar maximum of the past 100 years. In turn, these observations fueled more than a decade of theoretical advancement of magnetospheric-ionospheric electrodynamics and geomagnetic storm physics.

Low Temperature Measurements Of Resistivity In Low-Density Polyethylene, John R. Dennison, J. Brunson

All Physics Faculty Publications

Measurements of resistivity of low density polyethylene (LDPE) have been made using the standard constant voltage method to determine the temperature dependence of resistivity. Where electrons are assumed to serve as the primary charge carriers, their mobility is believed to be dependent on their probability of hopping between trapping sites treated as potential wells. We consider our measurements of this relatively simple polymeric material using temperature-dependant models of conduction mechanisms developed for amorphous solids and semi-conductors.

Observations Of A Noctilucent Cloud Above Logan, Utah (41.7°N, 111.8°W) In 1995, Joshua P. Herron, Vincent B. Wickwar, P J. Espy, J W. Merriwether

All Physics Faculty Publications

A Rayleigh-scatter lidar has been operated at the Atmospheric Lidar Observatory (ALO) on the Utah State University (USU) campus (41.7°N, 111.8°W) since August 1993. During the morning of 22 June 1995, lidar returns from a noctilucent cloud (NLC) were observed for approximately 1 hr, well away from the twilight periods when NLCs are visible. This detection of an NLC at this latitude shows that the first reported sighting, in 1999 (Wickwar et al., 2002), was not a unique occurrence. This 1995 observation differs from the 1999 one in that temperatures could be deduced. Near the 83-km NLC altitude the temperatures …

Hopping Conductivity In Low-Density Polyethylene, Jerilyn Brunson, John R. Dennison

All Physics Faculty Publications

Measurements of resistivity of low density polyethylene (LDPE) have been made using the standard constant voltage method to determine the temperature dependence of resistivity. Where electrons are assumed to serve as the primary charge carriers, their mobility is believed to be dependent on their probability of hopping between trapping sites treated as potential wells. We consider our measurements of this relatively simple polymeric material using temperature-dependant models of conduction mechanisms developed for amorphous solids and semi-conductors.

Deep Dielectric Charging Of Spacecraft Polymers By Energetic Protons, Nelson W. Green, John R. Dennison

All Physics Faculty Publications

The majority of research in the field of spacecraft charging concentrates on electron charging effects with little discussion of charging by protons. For spacecraft orbiting in the traditional LEO and GEO environments, this emphasis on electrons is appropriate since energetic electrons are the dominant species. But for spacecraft in orbits within the inner radiation belts or for interplanetary and lunar space probes, proton charging effects may also be of concern. To examine bulk spacecraft charging effects in these environments several typical highly insulating spacecraft polymers were exposed to energetic protons with energies from 1 MeV to 10 MeV to simulate …

Hands-On Gravitational Wave Astronomy: Extracting Astrophysical Information From Simulated Signals, Louis J. Rubbo, Shane L. Larson, Michelle B. Larson, Dale R. Ingram

All Physics Faculty Publications

In this article we introduce an activity in which introductory astronomy students act as gravitational wave astronomers by extracting information from simulated gravitational wave signals. The process mimics the way real gravitational wave analysis is handled by using plots of a pure gravitational wave signal. The students measure the properties of the simulated signal and use these measurements to evaluate standard relations for astrophysical source parameters. Although the activity described focuses on circular binaries, the techniques described can be applied to other gravitational wave sources as well. A problem based on the discussion in this paper is available for use …