Physical Sciences and Mathematics Commons^™

Hybrid Iterative Approach For Simulation Of Radio-Frequency Fields In Plasma, Vladimir A. Svidzinski, Jin-Soo Kim, Liangji Zhao, S. A. Galkin, Joseph Andrew Spencer

Physics Student Research

A novel iterative approach for solving discretized linear wave equations in a frequency domain, which combines time evolution with iterative relaxation schemes, is presented. In this hybrid approach, each iteration cycle consists of evolution of electromagnetic (EM) fields in time over a specified number of field periods followed by several iterative relaxations. Provided that there is sufficient dissipation, both the time evolution and the iterative relaxations contribute to the convergence of the EM fields to the solution of the formulated full wave boundary value problem. Time evolution rapidly distributes EM fields, propagating with group velocity, over the simulation domain, while …

Electron Yield Comparisons Of Low And High-Density Polyethylene, Jordan Lee

Physics Capstone Projects

With continued growth of the aerospace industry and further reliance on its communication infrastructure, a general idea of environmental stresses and material feedback is needed. Terrestrial-based labs attempt to recreate certain conditions seen in orbit and beyond, in order to gauge how materials and equipment will react. The Electron Emissions Test (EET) Chamber, an apparatus of USU's Material Physics Group, is used to test certain characteristics of materials in space-like environments. This experiment attempted to discern electron yield characteristics of two molecularly similar polymers: Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE).

The Role Of Fault-Zone Architectural Elements On Pore Pressure Propagation And Induced Seismicity, John P. Ortiz, Mark A. Person, Peter S. Mozley, James P. Evans, Susan L. Bilek

Geosciences Faculty Publications

We used hydrogeologic models to assess how fault‐zone properties promote or inhibit the downward propagation of fluid overpressures from a basal reservoir injection well (150 m from fault zone, Q = 5000 m3/day) into the underlying crystalline basement rocks. We varied the permeability of the fault‐zone architectural components and a crystalline basement weathered layer as part of a numerical sensitivity study. Realistic conduit‐barrier style fault zones effectively transmit elevated pore pressures associated with 4 years of continuous injection to depths of approximately 2.5 km within the crystalline basement while compartmentalizing fluid flow within the injection reservoir. The presence of a …

Reducing High Flows And Sediment Loading Through Increased Water Storage In An Agricultural Watershed Of The Upper Midwest, Usa, Nate Mitchell, Karthik Kumarasamy, Se Jong Cho, Patrick Belmont, Brent Dalzell, Karen Gran

Watershed Sciences Faculty Publications

Climate change, land clearing, and artificial drainage have increased the Minnesota River Basin’s (MRB) stream flows, enhancing erosion of channel banks and bluffs. Accelerated erosion has increased sediment loads and sedimentation rates downstream. High flows could be reduced through increased water storage (e.g., wetlands or detention basins), but quantifying the effectiveness of such a strategy remains a challenge. We used the Soil and Water Assessment Tool (SWAT) to simulate changes in river discharge from various water retention site (WRS) implementation scenarios in the Le Sueur watershed, a tributary basin to the MRB. We also show how high flow attenuation can …

Natural And Managed Watersheds Show Similar Responses To Recent Climate Change, Darren L. Ficklin, John T. Abatzoglou, Scott M. Robeson, Sarah E. Null, Jason H. Knouft

Watershed Sciences Faculty Publications

Changes in climate are driving an intensification of the hydrologic cycle and leading to alterations of natural streamflow regimes. Human disturbances such as dams, land-cover change, and water diversions are thought to obscure climate signals in hydrologic systems. As a result, most studies of changing hydroclimatic conditions are limited to areas with natural streamflow. Here, we compare trends in observed streamflow from natural and human-modified watersheds in the United States and Canada for the 1981–2015 water years to evaluate whether comparable responses to climate change are present in both systems. We find that patterns and magnitudes of trends in median …

Oscillation Of The Ionosphere At Planetary-Wave Periods, Jeffrey M. Forbes, Astrid Maute, Xiaoli Zhang, Maura E. Hagan

All Physics Faculty Publications

F‐region ionospheric oscillations at planetary‐wave (PW) periods (2–20 days) are investigated, with primary focus on those oscillations transmitted to the ionosphere by PW modulation of the vertically propagating tidal spectrum. Tidal effects are isolated by specifically designed numerical experiments performed with the National Center for Atmospheric Research thermosphere‐ionosphere‐electrodynamics general circulation model for October 2009, when familiar PW and tides are present in the model. Longitude versus day‐of‐month perturbations in topside F‐region electron density (Ne) of order ±30–50% at PW periods occur as a result of PW‐modulated tides. At a given height, these oscillations are mainly due to vertical oscillations in …

Drainage, Rebound And Oscillation Of A Meniscus In A Tube, Jeremy Marston, Garrett Toyofuku, Chao Li, Tadd T. Truscott, Jamal Uddin

Mechanical and Aerospace Engineering Faculty Publications

In this paper, the drainage and subsequent rebound of a liquid column in a cylindrical tube is examined experimentally and theoretically. When liquid is drawn up into a capillary and then released under gravity, inertia allows the meniscus to overshoot the equilibrium capillary rise height. The meniscus then rebounds up the tube, again overshooting the equilibrium height and undergoes oscillation. By varying both the immersion depth and radius of the tube, one can observe rich dynamical behavior, with the most dramatic being the formation of a fast liquid jet, barely visible to the naked eye but easily captured with high-speed …

Alaskan Marine Transgressions Record Out-Of-Phase Arctic Ocean Glaciation During The Last Interglacial, Louise Farquharson, Daniel Mann, Tammy M. Rittenour, Pamela Groves, Guido Grosse, Benjamin Jones

Geosciences Faculty Publications

Ongoing climate change focuses attention on the Arctic cryosphere’s responses to past and future climate states. Although it is now recognized the Arctic Ocean Basin was covered by ice sheets and their associated floating ice shelves several times during the Late Pleistocene, the timing and extent of these polar ice sheets remain uncertain. Here we relate a relict barrier-island system on the Beaufort Sea coast of northern Alaska to the isostatic effects of a previously unrecognized ice shelf grounded on the adjacent continental shelf. A new suite of optically stimulated luminescence dates show that this barrier system formed during one …

A Comparison Of R, Sas, And Python Implementations Of Random Forests, Breckell Soifua

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

The Random Forest method is a useful machine learning tool developed by Leo Breiman. There are many existing implementations across different programming languages; the most popular of which exist in R, SAS, and Python. In this paper, we conduct a comprehensive comparison of these implementations with regards to the accuracy, variable importance measurements, and timing. This comparison was done on a variety of real and simulated data with different classification difficulty levels, number of predictors, and sample sizes. The comparison shows unexpectedly different results between the three implementations.

Commuter Rail And The Landscape: Alternative Futures For Planning In Southeastern Box Elder County, C. Michael Gottfredson

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

This thesis analyzes the impact the FrontRunner commuter-rail service would have on Southeastern Box Elder County, Utah, using both anticipated future and alternative future scenarios created in a geographic information system (GIS). These alternative future scenarios include having the FrontRunner developed at anticipated stops and a transit-oriented development (TOD) scenario. Using techniques and methods developed by scholars in the bioregional planning field, these alternative future scenarios were compared against impact-data models addressing residential land-use suitability and landscape risk.

Outcomes: from this analysis, the TOD alternative future scenario had the least impact on landscape risk impact-data model. The TOD model …

A Framework For Assessing Natural Lands And Finding Common Ground In The Bear River Range, Scott Mccomb

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

Forests, wetlands, grasslands, lakes and deserts make up the natural lands that humans and nature rely on. In the Bear River Range, these lands are becoming smaller and more disconnected due to residential and commercial development, agriculture, energy production and transportation corridors. In addition, natural lands are owned and managed by a variety of groups representing different values, priorities and traditions. For large-scale conservation to be successful, it needs to incorporate multiple priorities. The purpose of this study was to provide a process for identifying the remaining network of natural lands within the Bear River Range that indicate high ecological …

The Perception Of Utah Division Of Wildlife Resource’S Law Enforcement By Local, County And Municipal Law Enforcement Agencies, Wyatt Bubak

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

Like most states throughout the nation, Utah’s population has continually grown since settlement. In 2014 Utah’s population was estimated at 2.95 million and between 2015-2016 Utah had the highest percentage growth rate of any state in the nation. This profound amount of growth can be attributed to many factors that are unique to Utah; two of which are the aesthetic and recreational opportunities available to Utah residents.

Due to population growth and urban sprawl, areas commonly patrolled by Utah Division of Wildlife Resources (UDWR) conservation officers are now located closer to urban populations. Previously rural or backcountry areas are seeing …

Analysis Of The Parkway Drive Landslide, North Salt Lake, Ut, Brianna V. Hill

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

On August 5^th, 2014, a hillside failed behind a North Salt Lake City, UT neighborhood threatening several homes. Aerial Photography, Digital Elevation Models (DEM), geochemistry, rain gage and seismic data were used to test the influence of contributing factors in this landslide failure. Aerial photographs available from 1993 to present were examined for signs of tension cracks suggesting impending ground motion, as well as documentation of human modification along the hillslope. Repeat DEM analysis of elevation and slope of the hillside before and after the slide were examined to characterize the pre-failure hillslope and subsequent landslide. Geochemical analyses …

Why Do They Do That? Understanding Factors Influencing Visitor Spatial Behavior In Parks And Protected Areas, Abigail M. Sisneros-Kidd

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Visitors to parks and protected areas within the United States and worldwide often visit these areas with a particular destination in mind, such as seeing Old Faithful erupt in Yellowstone National Park or standing on the rim of the Grand Canyon in Grand Canyon National Park. These visitor use destinations, and the pathways leading to them, such as trails and roadways, see high levels of use, and as a result, impacts to soil, vegetation, air, water, soundscapes, and night skies that result from this use. The field of recreation ecology studies these impacts to park and protected area resources resulting …

Engelmann Spruce Survival And Regeneration After An Epidemic Spruce Beetle Outbreak On The Markagunt Plateau In Southern Utah, Jessika M. Pettit

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bark beetle outbreaks are becoming more intense and severe when coupled with the effects of climate change. Engelmann spruce (Picea engelmannii) is one such species facing large-scale, epidemic spruce beetle outbreaks. Large-scale disturbances, such as beetle outbreaks, have major consequences for the future success of the ecosystem, thus highlighting the importance of understanding what promotes amplified outbreaks as well as their effects on future seedling establishment. Our research focused on two parts of a large-scale beetle outbreak: the mortality of spruce trees and the subsequent regeneration of seedlings. Our first study examined the timing of spruce mortality during …

Investigations Into Factors Affecting The Wpd-Loop In The Protein Tyrosine Phosphatases Yoph And Ptp1b, Gwendolyn Moise

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The research in this dissertation documents connections between the primary amino acid sequence of proteins, the dynamics of proteins, and their catalytic function. This research project studied two proteins called protein-tyrosine phosphatases (PTPs): the human enzyme PTP1B, and the bacterial enzyme YopH. PTP1B is a human enzyme that down regulates the insulin receptor on the outer cellular membrane, and causes the insulin receptor to be less responsive to insulin. A deeper knowledge of how PTP1B is different from other human PTPs might be useful in designing drugs to increase insulin sensitivity in diabetics. Yersinia Pestis is the bacteria that caused …

Towards The Prediction Of Climate Extremes With Attribution Analysis Through Climate Diagnostics And Modeling: Cases From Asia To North America, Boniface Opoku Fosu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This project summarizes the findings of research organized in two parts. The first involved the characterization of changes in the variability of climate that lead to extreme events. The second focused on the predictability of extreme climate on time-scales ranging from short forecast lead-times to long-lead climate predictions exceeding a year.

Initial studies focused on three interrelated, yet regionally unique extreme climate phenomena. First, the relationship between increasing greenhouse gas (GHG) emissions and particulate matter (PM) concentration in basin terrain was investigated. Next, we evaluated changes in large-scale atmospheric circulation associated with two climate phenomena at either extreme side of …

Three Essays On The Economics Of Controlling Mobile-Source Episodic Air Pollution, Ramjee Acharya

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cache County and the Wasatch Front, Utah have persistently experienced some of the nation’s worst air quality over the past decade. Elevated PM2.5 concentrations during wintertime “red air day” episodes frequently exceed the National Ambient Air Quality Standards (NAAQS). We investigate the possible effects of two different economic policies in controlling these regional problems. Adapting a model originally developed to calculate the social investment necessary to control nationwide disease outbreaks, we estimate an optimal preventative capital stock (for example, investment in public transportation) of between $4.1 million and $14.1 million to control red air day episodes in Cache County, and …

Feature Screening Of Ultrahigh Dimensional Feature Spaces With Applications In Interaction Screening, Randall D. Reese

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Data for which the number of predictors exponentially exceeds the number of observations is becoming increasingly prevalent in fields such as bioinformatics, medical imaging, computer vision, And social network analysis. One of the leading questions statisticians must answer when confronted with such “big data” is how to reduce a set of exponentially many predictors down to a set of a mere few predictors which have a truly causative effect on the response being modelled. This process is often referred to as feature screening. In this work we propose three new methods for feature screening. The first method we propose (TC-SIS) …

Use Of Verified Twitter Accounts During Crisis Events, Kai Anderson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis reports on the use of verified Twitter accounts during crisis events. Twitter is a social media platform that allows users to broadcast and exchange public text messages and it can be used as a communication tool during crisis events. Verified Twitter accounts are those accounts that Twitter has investigated and found to be genuinely maintained by the claimed owner. Celebrities, public officials, and other well-known persons or companies often seek this account status. The owners of these accounts are likely to provide more accurate or relevant information during a crisis event because they represent a brand, whether themselves …

A Deep Learning Approach To Recognizing Bees In Video Analysis Of Bee Traffic, Astha Tiwari

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Colony Collapse Disorder (CCD) has been a major threat to bee colonies around the world which affects vital human food crop pollination. The decline in bee population can have tragic consequences, for humans as well as the bees and the ecosystem. Bee health has been a cause of urgent concern for farmers and scientists around the world for at least a decade but a specific cause for the phenomenon has yet to be conclusively identified.

This work uses Artificial Intelligence and Computer Vision approaches to develop and analyze techniques to help in continuous monitoring of bee traffic which will further …

Word Recognition In Nutrition Labels With Convolutional Neural Network, Anuj Khasgiwala

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nowadays, everyone is very busy and running around trying to maintain a balance between their work life and family, as the working hours are increasing day by day. In such hassled life people either ignore or do not give enough attention to a healthy diet. An imperative part of a healthy eating routine is the cognizance and maintenance of nourishing data and comprehension of how extraordinary sustenance and nutritious constituents influence our bodies. Besides in the USA, in many other countries, nutritional information is fundamentally passed on to consumers through nutrition labels (NLs) which can be found in all packaged …

Canonical Coordinates On Lie Groups And The Baker Campbell Hausdorff Formula, Nicholas Graner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lie Groups occur in math and physics as representations of continuous symmetries and are often described in terms of their Lie Algebra. This thesis is concerned with finding a concrete description of a Lie group given its associated Lie algebra. Several calculations toward this end are developed and then implemented in the Maple Differential Geometry package. Examples of the calculations are given.

Implementing The Use Of Personal Activity Data In An Introductory Statistics Course, Lacy Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Integrating real data into a classroom is one of the recommendations in the Guidelines for Assessment and Instruction in Statistics Education (GAISE) college report which lays out guidelines for an introductory statistics course (Committee, GAISE College Report ASA Revision, 2016). In order to assess the effect of using real data in a classroom, the students received physical activity trackers to wear during an undergraduate introductory statistics course taught in the summer. This tracker, a Fitbit, enabled students to monitor and record their steps, calories, and active time throughout the class. Collecting personal activity data (PAD) creates a large database which …

Piezoresponse, Mechanical, And Electrical Characteristics Of Synthetic Spider Silk Nanofibers, Nader Shehata, Ishac Kandas, Ibrahim Hassounah, Patrik Sobolčiak, Igor Krupa, Miroslav Mrlik, Anton Popelka, Jesse Steadman, Randolph V. Lewis

Biology Faculty Publications

This work presents electrospun nanofibers from synthetic spider silk protein, and their application as both a mechanical vibration and humidity sensor. Spider silk solution was synthesized from minor ampullate silk protein (MaSp) and then electrospun into nanofibers with a mean diameter of less than 100 nm. Then, mechanical vibrations were detected through piezoelectric characteristics analysis using a piezo force microscope and a dynamic mechanical analyzer with a voltage probe. The piezoelectric coefficient (d₃₃) was determined to be 3.62 pC/N. During humidity sensing, both mechanical and electric resistance properties of spider silk nanofibers were evaluated at varying high-level …

Humans As Sensors: The Influence Of Extreme Heat Vulnerability Factors On Risk Perceptions Across The Contiguous United States, Forrest Scott Schoessow

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extreme heat events are the deadliest natural hazard in the United States and will continue to get worse in the coming years due to the effects of climate change. As a result, more people will experience deadly heat conditions. This highlights the need for decision-makers to develop better strategies for preventing future losses. How badly individuals are affected by extreme heat depends on many circumstances, such as how high temperatures actually are, weather conditions, and location. For example, a dry 90 °F day in Phoenix is probably more tolerable than a humid 90 °F day in New Orleans for most …

Teaching Landscape Construction Using Augmented Reality, Arshdeep Singh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis describes the design, development, and evaluation of an interactive Microsoft HoloLens application that projects landscape models in Augmented Reality. The application was developed using the Unity framework and 3D models created in Sketchup. Using the application, students can not only visualize the models in real space but can also interact with the models using gestures. The students can interact with the models using gaze and air-tap gestures.

Application testing was conducted with 21 students from the Landscape Architecture and Environmental Planning department at Utah State University. To evaluate the application, students completed a usability survey after using the …

Brun's 1920 Theorem On Goldbach's Conjecture, James A. Farrugia

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

One form of Goldbach’s Conjecture asserts that every even integer greater than 4is the sum of two odd primes. In 1920 Viggo Brun proved that every sufficiently large even number can be written as the sum of two numbers, each having at most nine prime factors. This thesis explains the overarching principles governing the intricate arguments Brun used to prove his result.

Though there do exist accounts of Brun’s methods, those accounts seem to miss the forest for the trees. In contrast, this thesis explains the relatively simple structure underlying Brun’s arguments, deliberately avoiding most of his elaborate machinery and …

Influence Of Global Atmospheric Circulation Variations On Weather And Climate Extremes, Yen-Heng Lin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Global warming and climate change deeply influence weather and climate extremes, causing substantial property damage and loss every year around the world. Given the importance of heating differences between low-latitude and Arctic regions, which produce heat sources and cold sources that each influence global circulations, we investigate three extreme weather events in different regions in order to better understand the possible connections between extreme events and global circulation changes.

This study begins with climate variations in the low-latitude western North Pacific. In early summer, the timing of the wet season has shifted from late May to early June since 1979. …

Affine Symmetry, Geodesics, And Homogeneous Spacetimes, David Maughan, Charles G. Torre

All Physics Faculty Publications

We show that the conservation laws for the geodesic equation which are associated to affine symmetries can be obtained from symmetries of the Lagrangian for affinely parametrized geodesics according to Noether's theorem, in contrast to claims found in the literature. In particular, using Aminova's classification of affine motions of Lorentzian manifolds, we show in detail how affine motions define generalized symmetries of the geodesic Lagrangian. We compute all infinitesimal proper affine symmetries and the corresponding geodesic conservation laws for all homogeneous solutions to the Einstein field equations in four spacetime dimensions with each of the following energy-momentum contents: vacuum, cosmological …