Digital Commons Network^™

Bidirectional Three-Phase Ac-Dc Power Conversion Using Dc-Dc Converters And A Three-Phase Unfolder, Weilun Warren Chen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Strategic use of energy storage systems alleviates imbalance between energy generation and consumption. Battery storage of various chemistries is favorable for its relatively high energy density and high charge and discharge rates. Battery voltage is in dc, while the distribution of electricity is still predominantly in ac. To effectively harness the battery energy, a dc-ac inverter is required.

A conventional inverter contains two high-frequency switching stages. The battery-interfacing stage provides galvanic isolation and switches at high frequency to minimize the isolation transformer size. The grid-interfacing stage also operates at high frequency to obtain sinusoidal grid currents and the desired power. …

Usarray Imaging Of North American Continental Crust, Xiaofei Ma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The layered structure and bulk composition of continental crust contains important clues about its history of mountain-building, about its magmatic evolution, and about dynamical processes that continue to happen now. Geophysical and geological features such as gravity anomalies, surface topography, lithospheric strength and the deformation that drives the earthquake cycle are all directly related to deep crustal chemistry and the movement of materials through the crust that alter that chemistry.

The North American continental crust records billions of years of history of tectonic and dynamical changes. The western U.S. is currently experiencing a diverse array of dynamical processes including modification …

Measurement Of Agriculture-Related Air Pollutant Emissions Using Point And Remote Sensors, Kori D. Moore

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Measuring air pollution emissions from agricultural activities is usually difficult because of their large area and variability. Traditional air quality sensors, called point samplers, measure conditions in one location, which may not adequately measure a plume. Remote sensors, instruments that measure pollution along a line rather than at a single point, are better able to measure conditions around large areas. This dissertation reports on four agricultural air emissions studies that used both point and remote sensors for comparison. The methods used to calculate the emissions are based on previous work and are further developed in these studies. In particular, an …

Investigation And Engineering Of Polyketide Biosynthetic Pathways, Lei Sun

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research is focused on investigation and engineering of natural product biosynthetic pathways for efficient production of pharmaceutically important molecules or generation of new bioactive molecules for drug development.

Natural products are an important source of therapeutics, such as chromomycin (anti-cancer), emodin (anti-inflammatory and anti-tumor) and sprolaxine (anti-Helicobacter pylori). Metabolic engineering of natural product biosynthetic pathways shows its promise for creating and producing valuable compounds with chemical diversity for drug discovery. One goal of this research is to create highly efficient strains to biosynthesize valuable natural products. The engineered Streptomyces roseiscleroticus strain constructed in this work showed higher …

Community Wildfire Planning And Design: A Review And Evaluation Of Current Policies And Practices In The Western United States, Carlene C. Klein

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildland fire is an important and complex issue, particularly in the fire-prone ecosystems of the Western United States. At the same time that the number of catastrophic wildland fires is increasing across the United States, more people are moving in to wildland areas growing the interface between urban and wildlands. Managing wildfire in the Western United States is becoming increasingly more complex and costly as growth and development continues to push the edge of municipalities into undeveloped wildlands. Communities in this wildland urban interface are exacerbating the problem of wildfire in the West.

With more people living in wildfire prone …

Approaches, Techniques, And Tools For Identifying Important Code Changes To Help Code Reviewers, Maneesh M. Mohanavilasam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Software development is a collaborative process where many developers come together and work on a project. To make things easy and manageable, software is developed on a version control system. A version control system is a centralized system which stores code and adds code from all other developers as an increment to the code base in the repository. Since multiple people work on the same code repository together, it is important to make sure that their contributions do not conflict with each other. It is important to maintain the quality and integrity of the repository. This is where the code …

The Biogeography And Nesting Biology Of Anthophora, With A Revision And Phylogeny Of The Anthophora (Micranthophora), Michael C. Orr

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bees are necessary pollinators for a vast array of different plants, including many which we rely on for food. In order to grow sufficient crops to feed the world’s growing population, we need to make sure our crops are visited by the most effective possible pollinators. However, this is complicated by the fact that there are over 4,000 bee species in North America, many of which vary in their pollination effectiveness and are difficult to identify. My dissertation’s first two data chapters focus on classifying the species of the xeric solitary bee group Anthophora subgenus Micranthophora, including seven newly …

Stillbirth: A Phenomenological Exploration Of The Clinical Encounter For Couples, Michael Q. King

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With approximately 65 stillbirths occurring each day in the United States, a significant number of parents are left to navigate a difficult grieving process. An event like stillbirth presents many individual and relational challenges. For this study, researchers focused on the hospital experience for couples following notification of stillbirth. Interviews were held with 8 couples that had experienced stillbirth within the past 10 years. Researchers wanted to know what similarities and differences existed in how mothers and fathers described the clinical encounter.

The data for this study were collected through interviews. Couples were encouraged to share as much or as …

Examining The Read-To-Write Strategy And Its Effects On Second Grader’S Writing Of Sequential Text, John Neal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Writing is so important. It is important in school and in our careers; writing is found to be helpful physiologically and psychologically. Experts wonder, with writing so important, why is writing not being adequately taught in the schools. The answer may be that writing is complex and teaching it is even more complex. The Read-to-Write Strategy is a writing model based on the study of exemplary models of text and children are explicitly taught how to write the way an author writes through a process of the teacher modeling how to write this way; the teacher sharing the writing task …

Assessment Of Restoration Seedings On Utah Watershed Restoration Initiative Project Sites, Lacey E. Wilder

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Overabundance of shrubs poses a major threat to semiarid ecosystems due to degraded understory vegetation. Previous efforts suggest a need for greater understanding of which management practices work best to improve these ecosystems. I sought to develop a better understanding of how the relative performance of commonly seeded species is influenced by three sagebrush removal techniques.

I calculated effect sizes for cover and frequency to estimate relative changes in abundance of 15 common plant species seeded at 63 restoration sites throughout Utah. Shrubs were reduced by fire or mechanical treatment. Effect sizes were assessed using meta-analysis techniques for two post-treatment …

A Parameterized Simulation Of Doppler Lidar, David B. Chester

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Upcoming missions to explore planetary bodies in the solar system will require accurate position and velocity data during descent in order to land safely at a predesignated site. A Doppler lidar instrument could provide measurements of the altitude, attitude, and velocity of the landing vehicle to supplement the data collected by other instruments. A flexible simulation tool would aid the tasks of designing and testing the functionality of such an instrument.

LadarSIM is a robust parameterized simulation tool developed for time of flight lidar at Utah State University's Center for Advanced Imaging Ladar. This thesis outlines how LadarSIM was modified …

Changing The World Through The Word: Developing Critical Consciousness Through Multicultural Children’S Literature With Critical Literacy In An Elementary Classroom, Hyekyoung Lee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to explore how fifth graders develop critical consciousness regarding the self and the world through critical literacy approaches using multicultural children’s literature. I employed Lewison, Flint, and Van Sluys’ four dimensions of critical literacy. I used a qualitative case study to design, frame and conduct this study in order to collect data and examine students’ cultural patterns including values, beliefs, behaviors, and language that they enacted in the critical literacy practices. I collected data through classroom observations, semi-structured students and teacher interviews, informal conversation, researcher’s reflective journal entries and field notes, and student-made artifacts. …

Mechanistic Studies Of The Iron And Molybdenum Nitrogenases, Derek Harris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As a basic building block in many biological molecules the element nitrogen (N) is essential for life. Dinitrogen (N2) is abundant in Earth’s atmosphere, but this form is biologically unavailable. To be biologically available N2 must undergo an energy demanding reduction reaction to the fixed form, ammonia (NH3). The industrial Haber-Bosch process, which accounts for approximately 50% of the worlds fixed nitrogen, uses energy from fossil fuels to achieve high pressures and temperatures to facilitate the reaction. The energy used by Haber-Bosch accounts for approximately 2% of the world’s annual supply. The remainder of fixed nitrogen is produced biologically by …

Estimating Evapotranspiration Using The Complementary Relationship And The Budyko Framework, Homin Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Land surface actual evapotranspiration (ET) is an important process in terrestrial water balance and reliable estimates of ET are necessary to improve water resources management. In this regard, there is a growing body of literature that recognizes the importance of an accurate ET model. Among them, the complementary relationship between ET and potential ET (ETP) has been the subject of many studies because it uses only meteorological data as inputs. However, there is an increasing concern that some complementary relationship models perform poorly under dry conditions. To overcome this limitation, this dissertation was designed to extend the latest complementary relationship …

Evidence-Based Practices For The Design Of Inclusive Playgrounds That Support Peer Interactions Among Children With All Abilities, Courtney L. Fernelius

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Play is necessary for the social, emotional, intellectual, and physical development of all children. Although playgrounds are designed to support the play of children, children with disabilities are often unable to fully participate in play on playgrounds. In part due to the lack of awareness of evidence-based practices supporting the play of children with disabilities, playground designers continue to perpetuate this disparity. Therefore, the purpose of this study was to determine the evidence-based practices for inclusive playground design that support peer interaction between children of all abilities, and to demonstrate how they can be implemented into a playground design.

A …

Reliability Underseepage Assessment Of Levees Incorporating Geomorphic Features And Length Effects, Lourdes Polanco Boulware

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It has been estimated that approximately fifty percent of the United States’ population lives behind levees. Because these earth structures are typically long, subjected to seasonal changes and spatial variability, it is logical to analyze them in an uncertainty-based approach. This research is focused on assessing the potential of internal erosion related failure due to underseepage with the general objective of assessing the failure potential of individual geomorphic features while considering length effects. The project team was granted $204,000 from the National Science Foundation and $10,000 from the United States Society on Dams which resulted in research collaboration within graduate …

Experimental And Simplified Analytical Investigation Of Full Scale Sandwich Panel Walls, Salam Adil. Al-Rubaye

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Concrete sandwich wall panels have been used for decades in the precast concrete construction industry because of their thermal efficiency. To achieve full or partial-composite action in concrete sandwich panel walls, the engineer must obtain a percent composite action from a connector manufacturer, making some engineers uncomfortable. Engineers are dependent upon the recommendations given by the connector manufacturers to establish their designs. This project tested six full scale sandwich panel walls to evaluate the percent composite action of various connectors and compare the results to those provided by the composite connector manufacturers.

This project aimed to validate current procedures using …

Novel Statistical Models For Quantitative Shape-Gene Association Selection, Xiaotian Dai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Other research reported that genetic mechanism plays a major role in the development process of biological shapes. The primary goal of this dissertation is to develop novel statistical models to investigate the quantitative relationships between biological shapes and genetic variants. However, these problems can be extremely challenging to traditional statistical models for a number of reasons: 1) the biological phenotypes cannot be effectively represented by single-valued traits, while traditional regression only handles one dependent variable; 2) in real-life genetic data, the number of candidate genes to be investigated is extremely large, and the signal-to-noise ratio of candidate genes is expected …

Urban Bobcat (Lynx Rufus) Ecology In The Dallas-Fort Worth, Texas Metroplex, Julie M. Golla

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Urban landscapes are quickly replacing native habitat around the world. As wildlife and people increasingly overlap in their shared space and resources, so does the potential for human-wildlife conflict, especially with predators. Bobcats (Lynx rufus) are a top predator in several urban areas across the United States and a potential contributor to human-carnivore conflicts. This study evaluated the movements and habitat use of bobcats in the Dallas-Fort Worth (DFW), Texas metroplex. Spatial data were collected from 10 bobcats via Global Positioning Satellite (GPS) for approximately one year. Average home range size was 4.60 km² (n=9, SE=0.99 km …

Investigation Of Concrete Electrical Resistivity As A Performance Based Test, Amir Malakooti

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research project was to identify the extent that concrete resistivity measurements (bulk and/or surface) can be used as a performance based lab test to improve the quality of concrete in Utah bridge decks. By allowing UDOT to specify a required resistivity, concrete bridge deck quality will increase and future maintenance costs will decrease.

This research consisted of two phases: the field phase and the lab phase. In the field phase, concrete samples were gathered from local concrete producers in Utah. These concrete samples were made with common concrete mixes used in bridge decks across the state …

Rancher Perceptions Of Ecosystem Services From Rangelands Of The Intermountain West, Elisabeth C. York

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rangelands within the Great Basin are responsible for the provision of multiple resources that humans depend on for a variety of reasons. Ranchers in this region are dependent on public lands to remain economically viable in their cattle operations. As a majority of land in this region is publically owned, there are varying interests at play in what should and could be the focus of management. Ranchers are charged with implementing strategies aimed at conserving these landscapes and their motivations for what to manage may significantly influence resource provision from Intermountain West ecosystem.

In this study, I sought to understand …

The Influence Of Varying Fiber Stacking Sequence On The Tensile, Impact, And Water Absorption Properties Of Unidirectional Flax/E-Glass Fiber Reinforced Epoxy Composite, Mohammed F. Al-Edhari

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis includes the study of the mechanical performance of two different types of fibers reinforced hybrid composites. Two kinds of fibers, natural fiber (flax) and synthetic fiber (E-glass), are used to reinforce epoxy resin. To evaluate the effective properties of the hybrid composites, a micromechanical analysis of the structure genome (SG) of a unidirectional fiber hybrid composites is performed using nite element analysis (FEA). Both fibers are assumed to be circular and packed in a hexagonal pattern. The effects of varying volume fractions and fiber locations, of the two fibers, on the elastic properties of the hybrid composites are …

Emotional Experience During Couple Support Interactions: The Role Of Attachment Anxiety And Avoidance, E. Megan Lachmar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Marriage and Family Therapy clinic at Utah State University conducted a study called the Relationship Checkup in which couple data was collected in an initial 2-hour session and feedback was provided for them in a follow-up 1-hour session. This checkup included completing self-report surveys, having an in-person interview, as well as couple interactions. The current study was carried out within the context of this broader relationship checkup, focusing on the couple support interactions, in which partners discussed a personal issue they would like to change about themselves.

Although a substantial amount of attention has been given to the role …

Exploring The Relationship Between The Use Of A Selected Phonics Curriculum And The Oral Reading Fluency And Nonsense Word Fluency Scores Of First-Grade Students, Bryce B. Day

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this quantitative study was to examine the effects, if any, of a supplemental phonics curriculum, Saxon Phonics, on the reading achievement of first-grade students in one mountain-west, semirural, school district. The design was casual-comparative and ex post facto, and answered the questions: (1) Do students taught using a traditional basal program and students taught using both the traditional basal program and a supplemental phonics program (control vs. treatment) differ on selected end-of-year reading achievement scores (i.e., portions of the DIBELS Next assessment—nonsense word fluency [NWF], oral reading fluency [ORF], and accuracy [ACC])? (2) do any possible …

Direct Effects Of Warming Increase Woody Plant Abundance In A Subarctic Wetland, Lindsay G. Carlson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change is expected to continue to cause large increases in temperature in Arctic and sub-Arctic ecosystems which has already resulted in changes to plant communities; for example, increased shrub biomass and range. It is important to understand how warmer temperatures could affect the plant community in a wetland system because this region provides crucial high-quality forage for migratory herbivores during the breeding season. One mechanism by which warming could cause change is directly, where warming influences the vital rates of a species; these effects may be either positive or negative. Warmer temperatures may also affect a species indirectly, by …

Wireless Power Transfer Roadway Integration, Trevor Gardner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Electric vehicles represent a major accomplishment in the energy and transportation industry. Unfortunately, they are restricted to a small travel range because of limited battery life. Successful integration of wireless power transfer (WPT) systems into the infrastructure would remove the range restrictions of EVs. To successfully integrate this technology, several requirements must be met. First, the embedment process cannot interfere with the electrical performance of the inductive power transfer (IPT) system. Second, the presence of the IPT system in the pavement structure cannot negatively affect the roadway’s lifespan.

Several systems were directly embedded in roadway materials. The electrical properties of …

The Field-Programmable Gate Array Design Of The Gridded Retarding Ion Distribution Sensor, Anthony P. Swenson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mankind's ability to predict weather on earth has been greatly enhanced by new instrumentation technology. Similarly, mankind's ability to predict space weather benefits from new technologies. Just as increasing the amount of atmospheric measurements on earth heightened mankind's ability to predict Earth weather, many scientists expect that expanding the amount of plasma measurements in space could be key to enhancing mankind's ability to predict space weather. Small satellites are one of these new technologies that have the potential to greatly enhance our ability to predict space weather. Utilizing many low-cost small satellites allows scientists to take data from more locations …

Extracting And Visualizing Data From Mobile And Static Eye Trackers In R And Matlab, Chunyang Li

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Eye tracking is the process of measuring where people are looking at with an eye tracker device. Eye tracking has been used in many scientific fields, such as education, usability research, sports, psychology, and marketing. Eye tracking data are often obtained from a static eye tracker or are manually extracted from a mobile eye tracker. Visualization usually plays an important role in the analysis of eye tracking data. So far, there existed no software package that contains a whole collection of eye tracking data processing and visualization tools. In this dissertation, we review the eye tracking technology, the eye tracking …

Toxicity And Mitochondrial Delivery Of Flavonol-Based Carbon Monoxide-Releasing Molecules, Hector Jose Esquer Heredia

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Despite the reputation of carbon monoxide (CO) as a silent killer, new evidence suggests that this gaseous molecule has anti-inflammatory, anti-cancer and vasoprotective properties. Unfortunately, little is known about the role of CO in the body. However, proteins present in mitochondria are believed to be important targets. We previously synthesized a class of novel and structurally modifiable flavonol-based CO-releasing molecules (CORMs). Flavonols are commonly found in fruits and vegetables. The base structure, Flav-1, is fluorescent, exhibits low toxicity, and releases CO after exposure to visible light. Previous reports indicate that addition of a triphenylphosphonium (TPP) tail allows chemical structures to …

Genetic Differentiation Of Two Species Of Buckwheat (Eriogonum), Jenessa Blotter Lemon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Limestone mining in the San Franicso Mountain Range of west central Utah threatens the survival of a rare endemic species of buckwheat (Eriogonum soredium). This species is an edaphic endemic, only found growing on the outcrops of the Ordovician limestone mines in the area. Eriogonum soredium is a candidate for governmental protection under the Endangered Species Act (ESA). However, a common, widespread buckwheat (Eriogonum shockleyi) appears to be closely related to the narrow endemic. The genetic relatedness of the rare and and common species will greatly influence the decision of United States Fish and Wildlife Service …