Physical Sciences and Mathematics Commons^™

Coherent And Incoherent Scatter Radar Study Of The Climatology And Day-To-Day Variability Of Mean F Region Vertical Drifts And Equatorial Spread F, J. M. Smith, F. S. Rodriques, B. G. Fejer, M. A. Milla

All Physics Faculty Publications

We conducted a comprehensive analysis of the vertical drifts and equatorial spread F (ESF) measurements made by the Jicamarca incoherent scatter radar (ISR) between 1994 and 2013. The ISR measurements allowed us to construct not only updated climatological curves of quiet-time vertical plasma drifts but also time-versus-height maps of ESF occurrence over the past two solar cycles. These curves and maps allowed us to better relate the observed ESF occurrence patterns to features in the vertical drift curves than previously possible. We identified an excessively high occurrence of post-midnight F region irregularities during December solstice and low solar flux conditions. …

Equatorial Vertical Drift Modulation By The Lunar And Solar Semidiurnal Tides During The 2013 Sudden Stratospheric Warming, A. Maute, B. G. Fejer, J. M. Forbes, X. Zhang, V. Yudin

All Physics Faculty Publications

During the 2013 stratospheric sudden warming (SSW) period the Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere (JULIA) radar at Jicarmarca, Peru, observed low-latitude vertical drift modulation with lows of 0-12 m/s daytime maximum drifts between 6-13 and 22-25 January and enhanced drifts up to 43 m/s between 15 snd 19 January. The NCAR thermosphere-ionosphere-mesosphere-electrodynamics general circulation model reproduces the prevailing vertical drift feature and is used to examine possible causes. The simulations indicate that the modulation of the vertical drift is generated by the beating of the semidiurnal solar SW2 and lunar M2 tides. During the SSW period …

Approximating Optimal Release In A Deterministic Model For The Sterile Insect Technique, Sergio Ramirez, Luis F. Gordillo

Mathematics and Statistics Faculty Publications

Cost/benefit analyses are essential to support management planning and decisions before launching any pest control program. In particular, applications of the sterile insect technique (SIT) are often prevented by the projected economic burden associated with rearing processes. This has had a deep impact on the technique development and its use on insects with long larval periods, as often seen in beetles. Under the assumptions of long adult timespan and multiple mating, we show how to find approximate optimal sterile release policies that minimize costs. The theoretical framework proposed considers the release of insects by pulses and finds approximate optimal release …

Canonical Models Of Dielectric Response, D. Mark Riffe

All Physics Faculty Publications

The interaction of electromagnetic fields with a solid is characterized by several interconnected response functions: the dielectric function ε(ω), index of refraction N(ω), conductivity σ(ω), and optical impedance Z(ω). Here we utilize three canonical models of dielectric response -- the damped harmonic oscillator, Debye polarization response, and the Drude model -- to discuss these four optical response functions. Special emphasis is devoted to the response of a Drude metal. Our main focus is on electromagnetic wave propagation through a material. We also discuss the relaxation of charge fluctuations within the context of the three canonical models of response.

Linearized Conformal Gravity, James Thomas Wheeler

All Physics Faculty Publications

We examine the linearization of Weyl conformal gravity, showing that the only solutions are also solutions to linearized general relativity

Electron Heat Flow Due To Magnetic Field Fluctuations, Jeong-Young Ji, Gunyoung Park, Sung Sik Kim, Eric D. Held

All Physics Faculty Publications

Radial heat transport induced by magnetic field line fluctuations is obtained from the integral parallel heat flow closure for arbitrary collisionality. The parallel heat flow and its radial component are computed for a single harmonic sinusoidal field line perturbation. In the collisional and collisionless limits, averaging the heat flow over an unperturbed surface yields Rechester-Rosenbluth like formulae with quantitative factors. The single harmonic result is generalized to multiple harmonics given a spectrum of small magnetic perturbations. In the collisionless limit, the heat and particle transport relations are also derived. © 2016 IOP Publishing Ltd.

The Schwarzschild Solution And Timelike Geodesics, Matthew Ross

Physics Capstone Projects

General Relativity is the standard theory of the gravitational interaction. It allows us to cal- culate the motions and interactions of particles in a non-Euclidean space-time. This presentation will present the derivation of the Schwarzschild metric tensor field by finding a solution of the Einstein Equation for a non-rotating, static vacuum. A general form of the metric for a static, spherically symmetric spacetime will be used to calculate the Riemann curvature tensor and sub- sequently the Ricci tensor and Ricci scalar which will then be used to find a vaccum solution to the Einstein Equation. Once the solutions of the …

Evidence Of Dispersion And Refraction Of A Spectrally Broad Gravity Wave Packet In The Mesopause Region Observed By The Na Lidar And Mesospheric Temperature Mapper Above Logan, Utah, T. Yuan, C. J. Heale, J. B. Snively, Xuguang Cai, P.-D. Pautet, C. Fish, Y. Zhao, Michael J. Taylor, W. R. Pendleton Jr., V. Wickmar, N. J. Michell

All Physics Faculty Publications

Gravity wave packets excited by a source of finite duration and size possess a broad frequency and wave number spectrum and thus span a range of temporal and spatial scales. Observing at a single location relatively close to the source, the wave components with higher frequency and larger vertical wavelength dominate at earlier times and at higher altitudes, while the lower frequency components, with shorter vertical wavelength, dominate during the latter part of the propagation. Utilizing observations from the Na lidar at Utah State University and the nearby Mesospheric Temperature Mapper at Bear Lake Observatory (41.9ÁN, 111.4ÁW), we investigate a …

An Introduction To Differential Geometry Through Computation, Mark E. Fels

Textbooks

The outline of the book is as follows. Chapter 1 reviews some basic facts about smooth functions from IRⁿ to IR^m, as well as the basic facts about vector spaces, basis, and algebras. Chapter 2 introduces tangent vectors and vector fields in IRⁿ using the standard two approaches with curves and derivations. Chapter 3 reviews linear transformations and their matrix representation so that in Chapter 4 the push-forward as an abstract linear transformation can be defined and its matrix representation as the Jacobian can be derived. As an application, the change of variable formula for vector …

Conformal Symmetry: Finding New Physics In Scale Invariance, Benjamin C. Lovelady

Research on Capitol Hill

Modern physics is the study of symmetry. Everything from electromagnetism to the famed Higgs mechanism stems from fundamental symmetries. These have fancy mathematical names and even fancier math behind them, but the basic idea is the same. These are mathematical generalizations of normal transformations such as rotating. These symmetries describe fields (electric, magnetic, etc.).

Most models of unification, i.e. string theory, use "Poincare symmetry." This symmetry includes both translations and rotations. This means physics only cares about relative position, angle, velocity, etc. If I were to wake up in a windowless room that had been moved a mile north and …

Sexual Assault And The Doctrine Of Chances In The Courtroom, Ryan Wallentine

Research on Capitol Hill

Sexual assault can have devastating and long-lasting effects on victims, but many assailants get away with their crime without being prosecuted.

The doctrine of chances is a rule of evidence allowing evidences of past crimes, wrongs, or acts to show it is unlikely a defendant would be repeatedly and innocently involved in similar, suspicious circumstances.

Given that about 63.3% of assailants are repeat offenders, the doctrine of chances could effectively be used in sexual assault cases.

The main objective is to determine a precise probabilistic threshold for allowing the use of the doctrine of chances in sexual assault cases such …

Stomatal Differences In Western Aspen And Linkage To Drought Tolerance, Brianne Palmer

Research on Capitol Hill

Aspen are the most widely distributed broadleaf tree in North America .However, aspen mortality is widespread across the Intermountain West. Researchers are attempting to determine the causes of the decline and propose future methods of management.

In order to survive, plants need to take in CO₂ through pores on their leaves called stomata. When the stomata are open, the plant takes in CO₂, however, water escapes. Therefore, stomata are important in regulating the drought response in plants. The size and the density of the stomata could influence the drought tolerance of an organism.

In Utah, there are …

Demographic Consequences Of Climate Change In The Uinta Ground Squirrel, Kari Norman

Research on Capitol Hill

One important impact of climate change is shifts in the timing of life events such as reproduction and flowering. Hibernators like the Uinta Ground Squirrel are especially sensitive to potential shifts because they depend on food at essential times.

Potential Regulation Of Deadly Water-Borne Shigella Bacteria Pathogenesis Through The Shigella Infection Protein Spa47, Jamie Kingsford

Research on Capitol Hill

• Shigella is a gram-negative, bacterial pathogen typically found in contaminated water sources.
• Each year, Shigella is responsible for over 90 million infections and 100,000 deaths stemming from symptoms of severe dysentery, fever, nausea and vomiting.
• A needle-like apparatus found on the surface of Shigella allows the bacterium to infect host cells.
• Each needle-apparatus has an associated ATPase, a protein that can hydrolyze ATP into ADP and P_i.
• The Shigella needle-apparatus ATPase Spa47 is predicted to provide the energy for infection.
• Spa47 has been shown to be essential for infection – without Spa47, no infection will occur.
• We were …

Using Accelerometer Data To Remotely Assess Predation Activity Of Arctic Wolves (Canis Lupus Arctos), Heather Shipp

Research on Capitol Hill

Arctic wolves (Canis lupus arctos) play an important role in ecosystems located in the far northern regions of the world; however, little information is available about them and their impacts on prey populations due to their remote location. Recently, there has been concern about declining caribou populations, which serve as an important food source for local Inuit peoples. As a result, there is an urgent need to better understand Arctic wolves and their influence on caribou abundance.

Dr. Dan MacNulty, a professor at Utah State University, is currently conducting research on Arctic wolves in the Fosheim Peninsula of Ellesmere Island, …

An Introduction To Differential Geometry Through Computation, Mark E. Fels

Mathematics and Statistics Faculty Presentations

No abstract provided.

Soil Organic Carbon As The Basis For Assessment Of Site Condition In Stands Of Quaking Aspen, Brian Rozick

Research on Capitol Hill

• Land managers need to be able to track site productivity changes based on past management
• Site quality assessments often extensive, expensive, specific, and confusing
• Soil Organic Carbon (SOC) = potential all encompassing indicator for site condition
• SOC central to healthy soil functions which contribute to a healthy site
• Research done in context of stands of Aspen (Populus tremuloides) on Cedar Mountain

Water Use Of Kentucky Bluegrass Varieties, Shawn Foster

Research on Capitol Hill

• With drought so prevalent in the West, water use on urban landscapes is being closely scrutinized with up to 60% of urban water use directed to landscape irrigation-primarily our lawns.
• Kentucky bluegrass (Poa pratensis L.) is widely used because of its soft texture, attractive color, and ability to recover from intensive use.
• More water-efficient varieties of Kentucky bluegrass may result in less irrigation yet maintain quality and function of the turf.

Experimental Evidence For Drought Induced Alternative Stable States Of Soil Moisture, David A. Robinson, Scott B. Jones, Inma Lebron, Sabine Reinsch, Maria T. Dominguez, Andrew R. Smith, Davey L. Jones, Miles R. Marshall, Bridget A. Emmett

Plants, Soils, and Climate Faculty Publications

Ecosystems may exhibit alternative stable states (ASS) in response to environmental change. Modelling and observational data broadly support the theory of ASS, however evidence from manipulation experiments supporting this theory is limited. Here, we provide long-term manipulation and observation data supporting the existence of drought induced alternative stable soil moisture states (irreversible soil wetting) in upland Atlantic heath, dominated by Calluna vulgaris (L.) Hull. Manipulated repeated moderate summer drought, and intense natural summer drought both lowered resilience resulting in shifts in soil moisture dynamics. The repeated moderate summer drought decreased winter soil moisture retention by ∼10%. However, intense summer drought, …

Sediment Supply Versus Local Hydraulic Controls On Sediment Transport And Storage In A River With Large Sediment Loads, David J. Dean, David J. Topping, John C. Schmidt, Ronald E. Griffiths, Thomas A. Sabol

Watershed Sciences Faculty Publications

The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphic data to determine the cumulative influence of different flood types on changing channel form. In this study, physically based analyses suggest that channel change in the Rio Grande is controlled by both changes in flow strength and …

Evidence Of Dispersion And Refraction Of A Spectrally Broad Gravity Wave Packet In The Mesopause Region Observed By The Na Lidar And Mesospheric Temperature Mapper Above Logan, Utah, Tao Yuan, Christopher J. Heale, Jonathan B. Snively, Xuguang Cai, Pierre-Dominique Pautet, C. Fish, Yucheng Zhao, Michael J. Taylor, William R. Pendleton Jr., V. Wickwar, Nicholas John Mitchell

Publications

Gravity wave packets excited by a source of finite duration and size possess a broad frequency and wave number spectrum and thus span a range of temporal and spatial scales. Observing at a single location relatively close to the source, the wave components with higher frequency and larger vertical wavelength dominate at earlier times and at higher altitudes, while the lower frequency components, with shorter vertical wavelength, dominate during the latter part of the propagation. Utilizing observations from the Na lidar at Utah State University and the nearby Mesospheric Temperature Mapper at Bear Lake Observatory (41.9°N, 111.4°W), we investigate a …

Building A Better Halide Receptor: Optimum Choice Of Spacer, Binding Unit, And Halosubstitution, Binod Nepal, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations are used to measure the binding of halides to a number of bipodal dicationic receptors, constructed as a pair of binding units separated by a spacer group. A number of variations are studied. A H atom on each binding unit (imidazolium or triazolium) is replaced by Br or I. Benzene, thiophene, carbazole, and dimethylnaphthalene are considered as spacer groups. Each receptor is paired with halides F-, Cl-, Br-, and I-. I-substitution on the binding unit yields a large enhancement of binding, as much as 13 orders of magnitude; a much smaller increase occurs for bromosubstitution. Imidazolium is a …

Predictive Formula For Electron Range Over A Large Span Of Energy, Anne C. Starley

Senior Theses and Projects

No abstract provided.

Predictive Formula For Electron Range Over A Large Span Of Energy, Anne Starley

Physics Capstone Projects

A model developed by the Materials Research Group that calculates electron penetration range of some common materials, has been greatly expanded with the hope that such extensions will predict the range in other, perhaps, more interesting materials. Developments in this extended model aid in predicting the approximate penetration depth into diverse classes of materials for a broad range of energetic incident electrons (<10 eV to >10 MeV, with better than 20% accuracy). The penetration depth—or range—of a material describes the maximum distance electrons can travel through a material, before losing all of its incident kinetic energy. This model has started to predict …

How Uncertainty In The Neutral Wind Limits The Accuracy Of Ionospheric Modeling And Forecasting, Michael David, Jan J. Sojka, Robert W. Schunk

Publications

One of the most important input fields for an ionospheric model is the horizontal neutral wind. The primary mechanism by which the neutral wind affects ionospheric densities is the inducement of an upward or downward ion drift along the magnetic field lines; this affects the rate at which ions are lost through recombination. The magnitude of this effect depends upon the dip angle of the magnetic field; for this reason, the impact of the neutral wind is somewhat less in polar regions than at mid-latitudes. It is unfortunate that observations of the neutral wind are relatively scarce, as compared for …

Energy Management System For Renewable Energy, Ashish R. Derhgawen

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

The demand for energy in our society has been increasing exponentially with our growing standard of living. The continued use of fossil fuels to meet these energy needs could lead to potentially catastrophic changes in the Earth's climate. Therefore, finding carbon-neutral energy sources and ensuring energy security are two of the biggest challenges that need to be addressed in the coming years. Recent technological innovations have finally brought us to the cusp of achieving these goals by providing cheap and reliable devices in micro-solar, smart homes , Internet of Things, etc. However, one of the biggest hurdles in the large-scale …

Blacksmith Fork - Little Bear Watershed Alternative Futures Study, Scott Mccomb, Emmet Pruss, Thomas Terry, Conner White

Bioregional Planning Studio Reports

The following project was carried out in conjunction with the Logan River Task Force, under the chairmanship of Dr. Frank Howe. The Logan River Task Force was formed to develop an overall approach for managing the Logan River that balances ecology with people's social values for the river including public safety and property protection. Although the work of the Task Force has focused primarily on the Logan river, the Bioregional Planning graduate students have provided the Task Force with contextual information about the watershed, by exploring alternative futures for the Blacksmith Fork and Little Bear watersheds. This work expands on …

High Altitude Payload For Cubesat Aeroboom Development, Jessica Gardiner

Physics Capstone Projects

The intent of this project was to create and launch a high altitude balloon flight for the continued research of the Utah State University CubeSat project. The High Altitude Payload for CubeSat Aeroboom Development (HAPCAD) is a direct support research project for the Get Away Special Passive Attitude Control Satellite (GASPACS). HAPCAD validated the aeroboom design and deployment mechanism by deploying an aeroboom in a near space environment. It was essential for the GASPACS payload to deploy in an environmental pressure lower than the internal aeroboom pressure for experimental success; this pressure is approximately 100 torr. The most effective time …

Using The Wsa Model To Test The Parker Spiral Approximation For Sep Event Magnetic Connections, S. W. Kahler, C. N. Arge, David Alan Smith

Physics Student Research

In studies of solar energetic (E > 10 MeV) particle (SEP) events the Parker spiral (PS) field approximation, based only on the measured 1 AU solar wind (SW) speed Vsw, is nearly always used to determine the coronal or photospheric source locations of the 1 AU magnetic fields. There is no objective way to validate that approximation, but here we seek guidelines for optimizing its application. We first review recent SEP studies showing the extensive use of the PS approximation with various assumptions about coronal and photospheric source fields. We then run the Wang-Sheeley-Arge (WSA) model over selected Carrington rotations (CRs) …

Population Density, Not Host Competence, Drives Patterns Of Disease In An Invaded Community, C. L. Searle

Mathematics and Statistics Faculty Presentations

Generalist parasites can strongly influence interactions between native and invasive species. Host competence can be used to predict how an invasive species will affect community disease dynamics; the addition of a highly competent, invasive host is predicted to increase disease. However, densities of invasive and native species can also influence the impacts of invasive species on community disease dynamics. We examined whether information on host competence alone could be used to accurately predict the effects of an invasive host on disease in native hosts. We first characterized the relative competence of an invasive species and a native host species to …