Physical Sciences and Mathematics Commons^™

Substrate Binding And Reduction Mechanism Of Molybdenum Nitrogenase, Zhiyong Yang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As a key constituent of proteins, nucleic acids, and other biomolecules, nitrogen is essential to all living organisms including human beings. Dinitrogen represents the largest pool of nitrogen, about 79% of the Earth’s atmosphere, yet it is unusable by most living organisms due to its inertness. There are two ways to fix this inert dinitrogen to usable ammonia. One is the industrial Haber-Bosch process, which needs to be conducted at high temperature and pressure. This process uses a lot of the non-renewable fossil fuel as the energy source. The other major pathway is the biological nitrogen fixation carried out by …

Alluvial Geochronology And Watershed Analysis Of The Golo River, Northeastern Corsica, France, Emilee M. Skyles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Golo River in Corsica, France, is a short, steep river (~95 km, 2706 m relief) in the Western Mediterranean with formerly glaciated headwaters. The small size and location of the Golo River make this system ideal for observing the influence of climate and sea-level change on river dynamics over the 100,000 years. A rapidly advancing dating technique, optically stimulated luminescence, was utilized to determine the timing of these river deposits on the coastal plain in order to frame them in the context of previous glacial and interglacial episodes. Climate fluctuations in the headwaters supplied the vast majority of sediment …

Unified Model Of Charge Transport In Insulating Polymeric Materials, Alec Sim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Charge transport, charging, and subsequent electrostatic discharge due to interactions with the space environment are primary concerns of spacecraft designers. Developing a physical understanding of the interactions of charge with the multitude of materials that spacecraft are composed of is a critical step in understanding and mitigating both short-term and long-term spacecraft degradation. In particular, the study of charge transport in highly insulating materials is critical as they store charge longer, with higher capacity, and with greater destructive capability than other materials.

The Utah State University Materials Physics Group, with the funding of the NASA James Webb Space Telescope project …

Effective Graph-Based Content--Based Image Retrieval Systems For Large-Scale And Small-Scale Image Databases, Ran Chang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Digital imaging was a great invention in the last century. Since digital cameras became popular in the public, a large amount of digital images emerged in the late of the twentieth century. How to manage the huge amount of images and find desired images among them became an urgent issue during the same period.

Techniques of retrieving a desired image are generally categorized into two basic classes. One relies on text-based key words to retrieve desired images in the image
database. The other one relies on image-based queries to retrieve desired images in the image database. The second technique is …

Mechanisms Of Vegetation-Induced Channel Narrowing On An Unregulated Canyon-Bound River, Rebecca Blanche Manners

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The accurate prediction of river channel width remains a fundamental area of investigation in the field of geomorphology. River managers and scientists are interested in understanding how a channel will respond to environmental perturbations such as altered runoff patterns from climate change, a new dam, or a pulse of sediment from a landslide. Increasingly, studies that focus on this question acknowledge the importance of accounting for the vegetation that lines the river banks. For this dissertation, I strove to identify some of the primary ways by which vegetation affects channel width.

At a fundamental level, vegetation influences the size of …

Two Scenes From Utah's Stratigraphic Record: Neoproterozoic Snowball Earth, Before And After, Dawn Schmidli Hayes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research is focused on rock units deposited in northern Utah before and after global glacial events of unprecedented magnitude, commonly referred to as
“Snowball Earth” glaciations. The rock units deposited prior to the beginning of these glaciations (~770 to 740 million years ago) include the Uinta Mountain Group in Utah’s Uinta Mountains. Rock units deposited after the glaciations (either ~665 or ~635 million years ago) include parts of the Kelley Canyon Formation on Antelope Island in the Great Salt Lake. These rocks, deposited in shallow ocean environments, record the history of life and ocean chemistry just before and after …

Modeling Habitat Use Of A Fringe Greater Sage-Grouse Population At Multiple Spatial Scales, Anya Cheyenne Burnett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) are a prominent bird species of sagebrush-dominated landscapes across the western United States. Over the past 15 years, sage-grouse have gained international attention due to decreasing population trends despite management efforts. In 2010 the U.S. Fish and Wildlife Service designated this species as warranted for listing under the Endangered Species Act, but the listing was precluded by other species at higher conservation risk. Habitat loss, degradation, and fragmentation have been implicated as primary sources of declines in sage-grouse distribution and abundance. The Bald Hills population in southwestern Utah occupies an area with …

Formation, Deformation, And Incision Of Colorado River Terraces Upstream Of Moab, Utah, Andrew P. Jochems

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The history of rivers is laid down as sediment in all landscapes, typically as a function of climate, geologic structures, and/or changes in sea level. When a river abandons its floodplain, this sediment collectively constitutes a landform called a fluvial terrace. Terraces are used to unlock prior characteristics of a river flowing through a given area at both local and regional scales. Dating terrace sediment allows comparison to known changes in climate and geologic deformation, two significant controls on the hydraulics of rivers and the deposition of their sediment loads.

The importance of terraces lies in their utility as markers …

On Mobile Detection And Localization Of Skewed Nutrition Facts Tables, Christopher Blay

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Computer Science Assistive Technology Laboratory (CSATL) at Utah State University has a long history of research in visually impaired grocery shopping tech. CSATL’s ShopMobile II introduced nutrition facts table (NFT) analysis but only with perfectly aligned and square input images.

A new method which detects and localizes NFTs more quickly and from rotated or non-square images has been released and is slated for integration with ShopMobile II to improve this feature substantially. This is great news for the estimated 3.6 million adults in the United States having visual impairment or blindness and also opens the doors to other applications …

Spatially Indexed Functional Data, Oleksandr Gromenko

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The increased concentration of greenhouse gases is associated with the global warming in the lower troposphere. For over twenty years, the space physics community has studied a hypothesis of global cooling in the thermosphere, attributable to greenhouse gases. While the global temperature increase in the lower troposphere has been relatively well established, the existence of global changes in the thermosphere is still under investigation.

A central difficulty in reaching definite conclusions is the absence of data with sufficiently long temporal and sufficiently broad spatial coverage. Time series of data that cover several decades exist only in a few separated (industrialized) …

Statistical Algorithms For Optimal Experimental Design With Correlated Observations, Chang Li

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The first part of my dissertation demonstrates that a modified simulated annealing algorithm can successfully determine highly efficient D-optimal designs for second order polynomial regression for a variety of correlated error structures.

In the second part, I solved weak universal optimal block designs for the nearest neighbor correlation structure and multiple block sizes, for the hub correlation structure with any block size, and for circulant correlation with odd block size.

In the third part, we propose an improved Particle Swarm Optimization (PSO) algorithm with time varying parameters. Then combining the theorem of decision making and PSO, we innovated nested PSO …

Fault Seal Analysis For Co2 Storage: Fault Zone Architecture, Fault Permeability, And Fluid Migration Pathways In Exposed Analogs In Southeastern Utah, David J. Richey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Anthropogenic carbon dioxide (CO₂) primarily resulting from the combustion of fossil fuels can be captured and stored by injection into underground porous sandstone reservoirs. This process has been proposed as a method for reducing greenhouse gas emissions that contribute to global warming. Two of the major risks associated with this technology include: 1) upwards migration and leakage of injected fluids along natural fault and fracture networks, and 2) possible induced seismicity (earthquakes) resulting from increasing the pressure in reservoirs and along existing faults.

We use geologic field mapping, petrographic analysis, characterization of the fault zone, analysis of altered …

Enhanced Structural Support Of Metal Sites As Nodes In Metal-Organic Frameworks Compared To Metal Complexes, Sanjit Das

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crystalline porous materials have gained long-standing interest for their application in gas storage, separation and catalysis. These materials have been useful for domestic, scientific and industrial purposes for many decades. Zeolites are a well known example of such materials.

Metal-organic frameworks are a new class of crystalline porous materials. They have many advantages over the more widely known zeolites. Though metal-organic frameworks are relatively new, their basic structure, known as the secondary building unit, very closely resembles the structure of metal complexes. Such metal complexes have been characterized in chemistry for more than a century.

Chemical catalysis is a process …

The Effects Of Abstraction On Best Nblock First Search, Justin R. Redd

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Search is an important aspect of Artificial Intelligence. Efficiently searching for solutions to large problems is important. One way to scale search large in problems quickly is to divide the work between multiple processors. There are many ways to divide this work using abstractions. This thesis examines the previous way this has been done in the past and introduces other ways to more efficiently divide the work and search in parallel.

A Middle To Late Holocene Record Of Arroyo Cut-Fill Events In Kitchen Corral Wash, Southern Utah, William M. Huff

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Arroyos are steeply entrenched channels that form by incision into weakly consolidated valley-fill alluvium. This study attempts to offers clues into the processes behind their formation by dating arroyo sediments using luminescence and radiocarbon techniques. The importance of understanding arroyo formation is due to a possible linkage with decadal to centennial-scale climate fluctuations. In the 1800s and early 1900s, many of the shallow, perennial streams throughout southern Utah that used for a variety of agricultural and domestic uses were incised up to ~30 m into their alluvium by frequent and high-magnitude flood events. The economical and ecological effects of these …

Carrier Dynamics In Ingaas/Gaas Quantum Dots Excited By Femtosecond Laser Pulses, Kripa Nidhan Chauhan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In semiconductors, everything is becoming smaller day by day; quantum dots are the smallest nanomaterials available today. Typical sizes of these quantum dots are in the range of 5 to 30 nm in diameter. Variations in size changes many material properties, such as electrical and nonlinear optical properties, making them very different from bulk semiconductors. The size of the QDs results in new quantum phenomena, which yield some extraordinary properties. Material properties change dramatically because quantum effects arise from the confinement of electrons and holes in the material. Hence, semiconductor quantum dots play an important role in designing new devices …

Weyl Gravity As A Gauge Theory, Juan Teancum Trujillo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A gauge theory is a theory in which the governing functional, known as the action, remains invariant under a continuous group of local transformations that form its symmetry. Each of the known fundamental interactions in the universe, such as electricity and magnetism, can be explained as arising from a particular gauge theory. Gravitation is no exception. Just as calculus can be used to find the value of a variable that maximizes or minimizes a function, calculus of variations can be used to find the equations, known as the field equations, that extremize the action, and these are the main equations …

Structural And Functional Characterization Of The Ldp3 (Vhz) Protein Tyrosine Phosphatase, Vyacheslav I. Kuznetsov

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Protein phosphorylation is as an important regulatory mechanism that controls a large number of physiologically important cellular processes. Proteins are phosphorylated on aliphatic (serine and threonine) as well aromatic (histidine and tyrosine) residues predominantly located on sterically accessible loops. Phosphorylation affects three- dimensional structures of proteins resulting in conformational changes which activate or deactivate enzymatic functions. Because of the ability of protein phosphorylation to modulate a multitude of diverse cellular processes, it became an appealing and promising target for drug therapy.

Attachment of phosphate is accomplished by kinases, whereas the removal of the phosphoryl group is performed by protein phosphatases. …

Applications Of Bayesian Statistics In Fluvial Bed Load Transport, Mark L. Schmelter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The science of fluvial sediment transport studies the processes involved in the movement of river sediments. It is commonly understood that when rivers flood they have a great capacity to move sand, gravel, and even larger cobbles and boulders. This process is not only limited to the big floods that usually attract so much attention, but also the more common river flows play a very important role in forming a river. As engineers and scientists, we like to be able to develop equations and relationships that describe some natural phenomenon—in this case, fluvial sediment transport. While we are able to …

Constraining Ice Advance And Linkages To Paleoclimate Of Two Glacial Systems In The Olympic Mountains, Washington And The Southern Alps, New Zealand, Cianna E. Wyshnytzky

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis investigates glacial sediments in the South Fork Hoh River Valley, Washington and the Lake Hawea Valley, New Zealand that were deposited during the last glacial period. Research objectives were to reconstruct the style and timing of glacier advance and retreat in both areas and to assess the viability of luminescence dating of sediments in glacial environments.

Glaciers are influenced primarily by temperature and precipitation. Valley glaciers, like those in the Olympics Mountains and Southern Alps, are thought to respond relatively rapidly to climate fluctuations in comparison to continental ice sheets. Understanding how these glacial systems responded to past …

Parallel Heat Transport In Magnetized Plasma, Mukta Sharma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A huge global increase in energy use is inevitable, so there is an urgent need to seek cleaner ways of producing energy on large scales. Fusion is the energy source of the universe and a promising way to fulfill energy needs of mankind for many centuries to come. It offers important advantages as a safe, sustainable, and environmentally friendly source of energy. The International Thermonuclear Experimental Reactor (ITER) aims to demonstrate magnetic fusion is an energy source of the future. The goal of ITER is to produce 500 MW of fusion power given 50 MW of input power—or ten times …

Concurrent Neurological And Behavioral Assessment Of Number Line Estimation Performance In Children And Adults, Joseph Michael Baker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding the brain’s response to common math-learning activities may help improve math education. For example, by imaging the brains of typically developing children and adults throughout a number line estimation task, it is possible to establish a baseline of what “typical” brains do in such situations. Thus, comparisons may be made to determine the degree to which brain functioning differs between typical and atypical math learners. Moreover, by identifying methods that may increase the brain’s response to real-world math activities, it may be possible to improve the math learning process for typical and atypical learners alike.

Brain imaging devices such …

Measurements Of The Temperature Dependence Of Radiation Induced Conductivity In Polymeric Dielectrics, Jodie Corbridge Gillespie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Radiation Induced Conductivity (RIC) is the change in conductivity of a material due to bombardment from incident high energy radiation. This study is to determine the effect of RIC and RIC's temperature dependence in polymeric dielectrics, specifically Kapton HN, Kapton E, PTFE Teflon, Tefzel, and Low Density Polyethylene (LDPE). Interest in these materials arises from applications for use in future spacecraft, specifically the James Webb Space Telescope (JWST).

One major issue in the design of JWST, as in all spacecraft, is the charging and arcing of exposed materials, resulting in fatal damage to the electronics and/or the craft itself. Particles …

The Chain-Link Fence Model: A Framework For Creating Security Procedures, Robert F. Houghton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Information technology security professionals are facing an ever growing threat to the networks that they defend. The process for creating procedures to help stem this threat is very difficult for security professionals. The Chain-Link Fence Model helps security professionals by guiding them through the process of creating and implementing new security procedures.

Lunar Tidal Effects In The Electrodynamics Of The Low-Latitude Ionosphere, Brian David Tracy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In order to model and perform better forecasts of the upper atmosphere, we have studied variations in the equatorial ionosphere due to lunar tidal forcing. We used extensive measurements made by the Jicamarca Unattended Long-Term Investigations of the Ionosphere and Atmosphere (JULIA) and Incoherent Scatter Radar (ISR) systems at Jicamarca, Peru during geomagnetic quiet conditions to determine the season, local time, and lunar age-dependent lunar tidal effects on equatorial vertical plasma drifts. The amplitudes and phases of the semimonthly and monthly lunar tidal perturbations were derived using a least squares method. Our results indicate that, as expected, lunar tidal effects …

Colorado River Cutthroat Trout Habitat Resistance And Resilience To Climate Change, Kate H. Olsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Government agencies and private organizations spend large amounts of public money attempting to return ecosystems to a more natural state, which have often been harmed or even destroyed as a result of modern development. Colorado River cutthroat trout, Oncorhyncus clarki pleuriticus, are a subspecies of cutthroat trout. Cutthroat trout live in the Rocky Mountains of the western United States. The population of this particular subspecies has been severely reduced by human actions, and currently only 12% of its historic populations still exist. To improve the condition of cutthroat trout, fisheries professionals and biologists are working to restore natural populations. …

Southward Continuation Of The San Jacinto Fault Zone Through And Beneath The Extra And Elmore Ranch Left-Lateral Fault Arrays, Southern California, Steven Jesse Thornock

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Clark fault is a significant fault within the southern San Andreas fault system. The Clark fault abruptly ends where it intersects a second, smaller fault that crosses it called the Extra fault zone. In this study we investigate the possibility of the Clark fault continuing beneath and beyond the Extra fault zone. Based on field mapping and other geological data that we present, we determine that the Clark fault continues below the Extra fault and is not evident on the surface. Over time, earthquake slip along the Clark fault has caused the Extra fault zone to rotate in a …

Empirical Properties Of Functional Regression Models And Application To High-Frequency Financial Data, Xi Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Functional data analysis (FDA) has grown into a substantial field of statistical research, with new methodology, numerous useful applications and interesting novel theoretical developments. My dissertation focuses on the empirical properties of functional regression models and their application to financial data. We start from testing the empirical properties of forecasts with the functional autoregressive models based on simulated and real data. We define intraday returns and consider their prediction from such returns on a market index. This is an extension to intraday data of the Capital Asset Pricing model. Finally we investigate multifactor functional models and assess their suitability for …

Dot Product Graphs And Their Applications To Ecology, Sean Bailey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We will introduce a new tool to visualize the comparison between different birds. This tool will allow users to use any number of measurable traits to see relationships between different birds, both individually and collectively.

Oxidative Aliphatic Carbon-Carbon Bond Cleavage Reactions, Caleb J. Allpress

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The work presented in this dissertation has focused on the activation and cleavage of chemical bonds between two carbon atoms. The selective oxidative activation of carbon-carbon bonds is important due to potential applications in the utilization of biomass for fuel production, applications in wastewater treatment and bioremediation, and in developing new reactions for organic synthesis of fine chemicals including pharmaceuticals. Ideally these reactions would be carried out with high atom economy at low temperatures and pressures, and using earth-abundant elements as reagents and catalysts. With these points in mind, nature provides an ideal model framework, carrying out its chemistry at …