Physical Sciences and Mathematics Commons^™

Evolution Of Thermally Annealed Graphitic Amorphous Carbon Towards Graphene: Structure, Vibrational Dynamics, Electron Emission And Band Gap, Jr Dennison, Jodie C. Gillespie, Sterling Smith

Presentations

No abstract provided.

Power And Charge Deposition And Electron Transport In Disordered Sio2 Layers Under Electron Bombardment, Greg Wilson, Jr Dennison, Amberly Evans Jensen, Justin Dekany

Presentations

No abstract provided.

Quantifying Night Sky Fluctuations: Striving For A Multi-Messenger Astronomy, Rachel K. Nydegger, Shane L. Larson Ph.D.

Browse All Undergraduate research

With LIGO coming back online soon, astronomers are attempting to solve the problems involved with coupling gravitational observations with electromagnetic telescope observations. To do this, my project aims to create all-sky surveys to characterize natural variability to reduce "false-alarm" rates in detections of gravitational emissions.

Prospects For Observing Ultracompact Binaries With Space-Based Gravitational Wave Interferometers And Optical Telescopes., T. B. Littenberg, Shane L. Larson, G. Nelemans Department Of Astrophysics, Radboud University Nijmegen, N. J. Cornish

All Physics Faculty Publications

Space-based gravitational wave interferometers are sensitive to the galactic population of ultra-compact binaries. An important subset of the ultra-compact binary popula- tion are those stars that can be individually resolved by both gravitational wave in- terferometers and electromagnetic telescopes. The aim of this paper is to quantify the multi-messenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher Information Matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 deg2 and bright enough to …

Strong Magnetic Field Effect On Over-The-Barrier Transport In Pb-P-Hg 1-Xcdxte Schottky Barriers, V. V. Radantsev, V. V. Zavyalov

All Physics Faculty Publications

It is usually believed that the over-the-barrier current in Schottky barriers (SB) on p-type semiconductor is controlled by heavy holes. However, there is an additional potential barrier caused by an oxide layer inevitably existing at the interface in real SB. For typical parameters of the barrier, its tunnelling transparency for light holes can be higher by three orders of magnitude than that for heavy holes. Thus, one can expect that the current is mainly due to the contribution of light holes. To clarify this problem, the investigation of carrier transport in a magnetic field is used as a key experiment …

How To Find Killing Vectors, Charles G. Torre

How to... in 10 minutes or less

We show how to compute the Lie algebra of Killing vector fields of a metric in Maple using the commands KillingVectors and LieAlgebraData. A Maple worksheet and a PDF version can be found below.

How To Find A Levi Decomposition Of A Lie Algebra, Ian M. Anderson

How to... in 10 minutes or less

We show how to compute the Levi decomposition of a Lie algebra in Maple using the command LeviDecomposition. A worksheet and corresponding PDF can be found below.

Beef Production And Consumption: Sustainable Alternatives, Roslynn Brain

Roslynn Brain

Sustainable living involves choosing a lifestyle with minimal environmental impacts. The ultimate goal is to leave future generations with a healthier environment than the one we were born into. How can we do that with beef consumption? Beef is part of American culture, so is there a way to make wiser choices when it comes to purchasing beef ? The short answer is, yes!

Coordinated Investigation Of Summer Time Mid-Latitude Descending E Layer (Es) Perturbations Using Na Lidar, Ionosonde, And Meteor Wind Radar Observations Over Logan, Utah (41.7°N, 111.8°W), Tao Yuan, Chad Fish, Jan Josef Sojka, D. Rice

All Physics Faculty Publications

It is well known that there is a strong correlation between the formation of a descending sporadic E layer (E_s) and the occurrence of large upper atmospheric zonal wind shears, most likely driven by solar thermal tides and/or gravity waves. We present new results of E_sperturbation events captured between 13 and 17 July 2011 (UT days 194–198) as part of a coordinated campaign using a wind/temperature Na lidar at Utah State University [41.7ºN, 111.8°W], and a Canadian Advanced Digital Ionosonde (CADI; Scientific Instrumentation Ltd., Saskatoon, Saskatchewan, Canada) and SkiYMet meteor wind radar, both located at nearby …

Development, Testing, And Deployment Of An Air Sampling Manifold For Spiking Elemental And Oxidized Mercury During The Reno Atmospheric Mercury Intercomparison Experiment (Ramix), B. D. Finley, D. A. Jaffe, K. Call, Seth Lyman, M. Sexauer Gustin, C. Peterson, M. Miller, T. Lyman

USU Uintah Basin Faculty Publications

The Reno Atmospheric Mercury Intercomparison Experiment (RAMIX) was in Reno, NV from August 22, 2011 to September 16, 2011. The goals of the experiment were to compare existing and new methods for measurements of ambient elemental and oxidized Hg, and to test these with quantitative spikes of Hg0, HgBr2, O3 and water vapor. In this paper we describe the design, testing, and deployment of a high flow manifold system designed to deliver ambient air and spiked compounds to multiple instruments simultaneously. The manifold was constructed of 1” OD PFA tubing and heated to 115 °C for the entire active zone. …

Characterizing Sky Variability For Multi-Messenger Astronomy, Rachel Nydegger

UCUR

Multi-messenger astronomy employs both electromagnetic and gravitational -wave detectors to paint a richer picture of celestial objects, providing more depth and information. The interferometers utilized for gravitational-wave observations receive input from very broad fields of view on the sky, typically a few square degrees. To have simultaneous electromagnetic observations (typically less than one square degree) requires innovative techniques for the telescopes to find the origin of radiation. One idea is to “tile” the view of the interferometer, using multiple telescopes to simultaneously point at different areas of the field to observe the source. One di"culty of this observing paradigm is …

How To Create A Jordan Algebra, Ian M. Anderson, Thomas J. Apedaile

How to... in 10 minutes or less

We show how to create a Jordan algebra in Maple using the commands AlgebraLibraryData and AlgebraData.

How To Create The Quaternion & Octonion Algebras, Ian M. Anderson, Thomas J. Apedaile

How to... in 10 minutes or less

We show how to create the quaternion and octonion algebras with the DifferentialGeometry software. For each algebra, there is a split-form also available.

Fast Time Resolution Oxidized Mercury Measurements During The Reno Atmospheric Mercury Intercomparison Experiment (Ramix), Jesse L. Ambrose, Seth N. Lyman, Jiaoyan Huang, Mae Sexauer Gustin, Daneil A. Jaffe

USU Uintah Basin Faculty Publications

The Reno Atmospheric Mercury Intercomparison Experiment (RAMIX) was carried out from 22 August to 16 September, 2011 in Reno, NV to evaluate the performance of new and existing methods to measure atmospheric mercury (Hg). Measurements were made using a common sampling manifold to which controlled concentrations of Hg species, including gaseous elemental mercury (GEM) and HgBr2 (a surrogate gaseous oxidized mercury (GOM) compound), and potential interferents were added. We present an analysis of Hg measurements made using the University of Washington’s Detector for Oxidized Hg Species (DOHGS), focusing on tests of GEM and HgBr2 spike recovery, the potential for interference …

Faraday Cup Designs For High Efficiency Determination Of Energy- And Angular-Resolved Charged Particle Fluxes, Kent D. Hartley

Senior Theses and Projects

Faraday cups provide a simple and efficient apparatus to measure the absolute magnitude of charge particle fluxes, and with the addition of a retarding field analyzer and defining apertures the capability to determine the energy and angular distributions of the fluxes. Through careful design of the electron optics, a Faraday cup can be tailored to meet specific requirements for detector size, minimum detectable flux, collection efficiency, absolute accuracy, energy discrimination, and angular resolution. This project explores optimal design concepts through electric field and charged particle trajectory simulations, theoretical analysis, and evaluation of experimental prototypes to develop compact, high efficiency Faraday …

Physics 3710 – Exam I, David Peak

Exams

No abstract provided.

Feasibility Of High-Density Climate Reconstruction Based On Forest Inventory And Analysis (Fia) Collected Tree-Ring Data, R. Justin Derose, Shih-Yu (Simon) Wang, John D. Shaw

Wasatch Dendroclimatology Research

This study introduces a novel tree-ring dataset, with unparalleled spatial density, for use as a climate proxy. Ancillary Douglas fir and pin˜ on pine tree-ring data collected by the U.S. Forest Service Forest Inventory and Analysis Program (FIA data) were subjected to a series of tests to determine their feasibility as climate proxies. First, temporal coherence between the FIA data and previously published tree-ring chronologies was found to be significant. Second, spatial and temporal coherence between the FIA data and water year precipitation was strong. Third, the FIA data captured the El Nin˜o–Southern Oscillation dipole and revealed considerable latitudinal fluctuation …

Extension Sustainability: Research, Outreach, And Communication Techniques To Foster Positive Change, Roslynn Brain

Environment and Society Faculty Publications

No abstract provided.

Using Sdo-Eve Satellite Data To Model For The First Time How Large Solar Flares Influence The Earths Ionosphere, Joseph B. Jensen, Jan J. Sojka, Michael David, Bob Schunk, Tom Woods, Frank Eparvier

Research on the Hill (Salt Lake City)

The ionosphere is important in our everyday communicaBons. Many satellites, like GPS satellites, have to send signals through the ionosphere, and many emergency radio communicators depend on the ionosphere to extend the range of their communicaBons. We also have many satellites and even the InternaBonal space staBon located in this region of the atmosphere. It becomes important for the astronauts in the ISS and for the health of the satellites to know what is going on in the ionosphere and how it can affect their systems.

The lower regions are important because the E-­‐region will extend the distance that a …

Mapping Light Pollution At Utah State University, Rachel Nydegger, Shane L. Larson

Research on the Hill (Salt Lake City)

One of the beauties of modern civilization is seeing the city lighting at night. It provides a feeling of security and is indicative of the power and endeavors of humanity, but over-lighting is a form of pollution. Many outdoor light fixtures spread light in all directions, sending a majority of the light into the sky, away from where we want the light to be on the ground. This light spreading upward is not only wasted light, but it is wasted energy and money, destroys our ability to view the night sky, and has profound effects on nocturnal creatures. The direct …

Simulation Of Uv Radiation Degradation Of Polymers On Misse-6 In The Low Earth Orbit Environment, Kelby T. Peterson, Jr Dennison

Research on the Hill (Salt Lake City)

The Sate of Utah Space Environment & Contamination Study (SUSpECS) experiment flown on the Materials International Space Station Experiment 6 (MISSE-6) was an experiment designed to examine the consequences of the space environment on various materials used in space-component design. SUSpECS was comprised of approximately 180 samples that were suspended from the side of the International Space Station (ISS) for 18 months and returned to allow for pre- and post-flight comparisons. The sample with the most evident changes was a thin film of polyethylene terephthalate (PET) MylarTM coated with Vapor Deposited Aluminum (VDA). The post- flight analysis showed evidence of …

Do We Understand What The Mercury Speciation Instruments Are Actually Measuring? Results Of Ramix, Mae Sexauer Gustin, Jiaoyan Huang, Matthieu B. Miller, Christianna Peterson, Daniel A. Jaffe, Jesse Ambrose, Brandon D. Finley, Seth N. Lyman, Kevin Call, Robert Talbotl, Dara Feddersen, Huiting Mao, Steven E. Lindberg

USU Uintah Basin Faculty Publications

From August 22 to September 16, 2012, atmospheric mercury (Hg) was measured from a common manifold in the field during the Reno Atmospheric Mercury Intercomparison eXperiment. Data were collected using Tekran systems, laser induced fluorescence, and evolving new methods. The latter included the University of Washington-Detector for Oxidized Mercury, the University of Houston Mercury instrument, and a filter-based system under development by the University of Nevada-Reno. Good transmission of total Hg was found for the manifold. However, despite application of standard protocols and rigorous quality control, systematic differences in operationally defined forms of Hg were measured by the sampling systems. …

Factors Influencing Survival And Productivity Of Pronghorn In A Semiarid Grass-Woodland In East-Central New Mexico, Louis C. Bender, Jon C. Boren, Heather Halbritter, Shad Cox

Human–Wildlife Interactions

Pronghorns (Antilocapra americana) are an important source of revenue and recreation for property managers throughout New Mexico, but have been declining in number. We documented body condition, survival, production of fawns, and trends in population size of pronghorns on the Corona Range and Livestock Research Center (CRLRC), a working research ranch and wildlife enterprise located in east-central New Mexico, from 2006 through 2011. Accrual of all indices of condition and size of both adult female and adult male pronghorns was positively associated with precipitation during June to July, August to September, and annually. Annual survival rates of females …

Galaxy Inclination And Surface Brightness, Jordan C. Rozum, Shane L. Larson

Student Showcase

The distribution of spiral and bar galaxy inclination angles is expected to be uniform. However, analysis of several major galaxy catalogs shows this is not the case; galaxies oriented near edge-on are significantly more common in these catalogs. In an attempt to explain this discrepancy, we have developed a galaxy simulation code to compute the appearance of a spiral type galaxy as a function of its morphological parameters. We examine the dependence of observed brightness upon inclination angle by using smooth luminous mass density and interstellar medium (ISM) density distributions. The luminous mass component is integrated along a particular line …

High-Latitude Short-Period Mesospheric Gravity Wave Dynamics And Winter Climatology, Michael Negale, Kim Nielsen, Michael J. Taylor, Dominique Pautet, Margit Dyrland

Physics Student Research

Short-period gravity wave observations over the Arctic region are few and their impact on the Arctic mesosphere lower thermosphere region via momentum deposition is of high interest. The Mesospheric Airglow Imaging and Dynamics project was initiated in January 2011 to investigate the presence and dynamics of these waves over the interior of Alaska. Observations were made from Poker Flat Research Range (PFRR) using an all-sky imager. This site provides an exceptional opportunity to establish a long-term climatology of short-period gravity waves in the Arctic Region. We present summary measurements of prominent gravity waves over two consecutive winters and compare their …

Gravitational Gauge Theory And The Existence Of Time, James Thomas Wheeler

All Physics Faculty Publications

General relativity may be formulated as a gauge theory more than one way using the quotient manifold approach. We contrast the structures that arise in four gravitational gauge theories, three of which give satisfactory gauge theoris of general relativity. Of particular interest is the quotient of the conformal group of a flat space by its Weyl subgroup, which always has natural symplectic and metric structures in addition to the requisite manifold. This quotient space admits canonically conjugate, orthogonal, metric submanifolds distinct from the original space if and only if the original flat space has signature n, -n or 0. In …

Small-Scale Simulation Chamber For Space Environment Survivability Testing, Robert H. Johnson, Lisa D. Montierth, Jr Dennison, James S. Dyer, Ethan R. Lindstrom

Browse All Undergraduate research

A vacuum chamber was designed that simulates the space environment to facilitate tests of material modification due to space environment interactions. Critical environmental elements to be simulated include an ultra high vacuum, a FUV/UV/VIS/NIR solar spectrum, an electron plasma flux, temperature extremes, and long duration exposure. To simulate the solar electromagnetic spectrum (EMS), a solar simulator was used with a range of 200 nm to 2000 nm. A Krypton lamp provides surrogate radiation for the prominent far ultraviolet hydrogen Lyman-α 120 nm emission not produced by the solar simulator. A mono-energetic electron flood gun (20 eV to 15 keV) provides …

Carrier Capture Dynamics Of Single Ingaas/Gaas Quantum-Dot Layers, Kripa N. Chauhaun, D. Mark Riffe, Addison E. Everett, D. J. Kim, H Yang, F. K. Shen

All Physics Faculty Publications

Using 800nm, 25-fs pulses from a mode locked Ti:Al2O3 laser, we have measured the ultrafast optical reflectivity of MBE-grown, single-layer In0.4Ga0.6As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and annealing temperature. With increasing excited carrier density, the …

Carrier Capture Dynamics Of Single Ingaas/Gaas Quantum-Dot Layers, K. N. Chauhan, D. Mark Riffe, E. A. Everett, D. J. Kim, H. Yang, F. K. Shen

All Physics Faculty Publications

Using 800 nm, 25-fs pulses from a mode locked Ti:Al₂O₃ laser, we have measured the ultrafast opticalreflectivity of MBE-grown, single-layer In_0.4Ga_0.6As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140 fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and …

Properties Of Cathodoluminescence For Cryogenic Applications Of Sio2-Based Space Observatory Optics And Coatings, Amberly Evans Jensen, Jr Dennison, Gregory Wilson, Justin Dekany, Charles Bpwers, Robert Meloy, James B. Heaney

Conference Proceedings

Disordered thin film SiO2/SiOx coatings undergoing electron-beam bombardment exhibit cathodoluminescence, which can produce deleterious stray background light in cryogenic space-based astronomical observatories exposed to high- energy electron fluxes from space plasmas. As future observatory missions push the envelope into more extreme environments and more complex and sensitive detection, a fundamental understanding of the dependencies of this cathodoluminescence becomes critical to meet performance objectives of these advanced space-based observatories. Measurements of absolute radiance and emission spectra as functions of incident electron energy, flux, and power typical of space environments are presented for thin (~60-200 nm) SiO2/SiOx optical coatings on reflective metal …