Digital Commons Network^™

Quantifying Volatile Fatty Acid Concentrations During The Pretreatment And Anaerobic Digestion Process, Sascha Boutelle

Theses and Dissertations

Producing renewable energy from biomass or from the wastewater treatment process has gained momentum in the past 20 years. Anaerobic digestion has historically been used as one step in the waste treatment process, to both reduce the mass of waste that needs to be disposed of and to generate biogas. This process is typically only able to reduce 30-40% of the waste mass because of the recalcitrant nature of the waste streams being treated. Anaerobic pretreatment with the thermophilic bacteria Caldicellulosiruptor bescii (C. bescii) has been proven to increase the percentage of mass digested and consequently increase methane production to …

Understanding The Ahupua'a: Using Remote Sensing To Measure Upland Erosion And Evaluate Coral Reef Structure, Logan Kalaiwaipono Ellis

Theses and Dissertations

Under ever intensifying pressures from land use, climate change, and erosion, tropical islands are among the most vulnerable systems in the world. Terrestrial systems are weakened by intensifying land use patterns, the weakening of which is highlighted when high intensity rainfall events erode sediment and leads to sediment deposition on the marine system. The deposition of sediment on the marine system is a major stressor that can lead to weakened coral reefs and a decrease in marine resources commonly gathered for food. These interactions have led to the emergence of biocultural resource management strategies, one of which is the ahupua'a …

Low Noise Front End Signal Transport Design For L-Band Phased Array Receivers, Spencer M. Ammermon

Theses and Dissertations

RF receiver improvements in size, weight, power, and sensitivity are constant goals in the wireless communications community. The combination of phased array antenna systems with high speed analog to digital converters helps engineers meet these goals, because many of the analog components and tasks found in a traditional receive chain are moved into the digital domain. Although the hard work of signal reception is moved into digital signal processing, digital receivers rely on a high performance analog front end to properly condition a signal before analog to digital conversion. In this thesis, two RF front ends are developed for direct …

Do Esl Students Progress An Entire Actfl Proficiency Sublevel In Both Speaking And Writing Each Semester?, Matthew Salvatore Millar

Theses and Dissertations

Many intensive English language students take pretests and posttests at the beginning and end of each semester to determine proficiency gains. Nevertheless, it may not be clear what kinds of gains should be expected over the course of a single semester or how those gains might be influenced by factors such as the learner's first language (L1) or prior proficiency. This study used repeated measures ANOVA and nonparametric tests to examine the speaking and writing pretest and posttest scores of 2331 Novice Mid to Advanced Mid ESL learners over a 15-week semester. Results show that while students on average progressed …

Effect Of X-Ray Illumination On Magnetic Domain Memory In [Co/Pd]/Irmn Multilayers, Colby Singint Walker

Theses and Dissertations

This thesis focuses on investigating the possible x-ray illumination effects on the magnetic domain memory (MDM) in magnetic [Co/Pd]IrMn multilayers. In this material, MDM is induced via exchange couplings between the ferromagnetic Co/Pd layer and the antiferromagnetic IrMn layer. To carry out this investigation, we have used magneto-transport and x-ray resonant magnetic scattering. The use of magneto-transport in-situ at synchrotron x-ray scattering facility has allowed us to follow the gradual effect of x-ray illumination on the amount of exchange bias, initially present after field cooling the material. With our in-situ measurements we have been able to see that x-ray illumination …

Of Bugs And Wildfires: Tracing The Impacts Of Changing Wildfire Regimes On Aquatic Bacteria And Macroinvertebrates Using Edna, Isabella M. Errigo

Theses and Dissertations

Human disruption of climate, habitat, and ignition has altered the behavior of wildland fire at local to continental scales. In many regions, novel fire regimes are emerging that threaten to exceed the capacity for local management to protect human wellbeing and ecosystem function. Simultaneous changes in climate, species composition, and fire management have resulted in extreme fire behavior in many regions. For the Western United States, the emerging novel fire regime consists of more frequent, severe, and intense wildfires, with annual area burned by wildfire having doubled and high-severity wildfire area having increased 8-fold since the 1980s. The impacts of …

Leveraging Fpga Primitives To Improve Word Reconstruction During Netlist Reverse Engineering, Reilly Mckendrick, Corey Simpson, Brent Nelson, Jeffrey Goeders

Faculty Publications

While attempting to perform hardware trojan detection, or other low-level design analyses, it is often necessary to inspect and understand the gate-level netlist of an implemented hardware design. Unfortunately this process is challenging, as at the physical level, the design does not contain any hierarchy, net names, or word groupings. Previous work has shown how gate-level netlists can be analyzed to restore high-level circuit structures, including reconstructing multi-bit signals, which aids a user in understanding the behavior of the design. In this work we explore improvements to the word reconstruction process, specific to FPGA platforms. We demonstrate how hard-block primitives …

Interpretive Language And Museum Artwork: How Patrons Respond To Depictions Of Native American And White Settler Encounters--A Thematic Analysis, Holli D. Rogerson

Theses and Dissertations

The purpose of this study is to conduct a thematic linguistic analysis of survey responses to museum-quality images depicting various Native American and white settler encounters. The survey asked participants to provide written responses (fill in the blank prompts) to a selection of twelve images composed of photographs and paintings representing one or more of three overarching themes: violence, immersion, and goodwill/collaboration. The research focused on four demographic groups: Latter-day Saints, Native Americans, museum employees, and total participants. Each response was individually analyzed by hand and assigned appropriate classification tags based on the types of words their responses contained including …

Analyzing Patterns Of Complexity In Pre-University L2 English Writing, Zachary M. Lambert

Theses and Dissertations

The present study involves the creation and analysis of a corpus containing 7747 samples of timed, pre-matriculated L2 English writing from an IEP. The focus of the analysis is on three phrasal complexity measures with time and proficiency as fixed effects, examining their impact on each measure. Results of the analysis suggest that this is true for some phrasal measures, such as nominalizations and attributive adjectives, while others, such as noun-noun phrases, may indicate a lower level of proficiency or lesser allotted writing time. Nominalizations in particular demonstrated a strong relationship with both allotted time and proficiency, further suggesting that …

A Usability Study Of Fido2 Hardware Tokens On Mobile Devices, Stephen Lambert

Theses and Dissertations

Passwords as the primary form of authentication on the web have many issues, such as password re-use across sites and difficulty in remembering secure passwords. The FIDO Alliance has created a passwordless system that has with support from companies like Google, Apple, and Microsoft: FIDO2. Studies have shown so far that users find FIDO2 usable on personal computers, but no work has been published on its usability on mobile devices. I conducted a lab study in which participants used FIDO2 passwordless authentication with hardware tokens on a mobile phone. Participants found FIDO2 usable on mobile devices, but had similar fears …

Examining The Willingness To Communicate (Wtc) Scale With Advanced Foreign Language Learners, Colin Lilya

Theses and Dissertations

This study explored the effectiveness of a Willingness to Communicate (WTC) scale with advanced foreign language (L2) learners. The WTC instrument included sections on communicating with native speakers of the L2 and peer language learners in various settings (at home, abroad, in-class and online). As most prior research had focused on beginning language learners, for this study, we recruited participants who began to learn their respective languages in informal, long-term immersion settings. Participants took the WTC survey as part of a larger self-assessment instrument with a subset of 600 intermediate and advanced level Spanish (n = 339), Portuguese (n = …

Effect Of Climate History On The Genetic Structure Of An Antarctic Soil Nematode, Abigail C. Jackson

Theses and Dissertations

Historical climate disturbances such as glacial cycling and fluctuating stream, lake, and sea levels strongly influence the distribution and evolutionary trajectories of Antarctic terrestrial species. Antarctic invertebrates, with limited long-range mobility, including the ubiquitous sentinel nematode species Scottnema lindsayae, are especially sensitive to climate disturbances. We tested hypotheses associated with the historical geographic and population genetic structure of this species as it occurs across the McMurdo Dry Valleys (MDVs) of Antarctica. In order to reconstruct the influence of climate disturbance and ecological conditions on this species, partial mitochondrial COI gene sequences were sequenced and analyzed from individual S. lindsayae collected …

Computational Tools For Modeling And Simulation Of Sooting Turbulent Non-Premixed Flames, Victoria B. Stephens

Theses and Dissertations

Turbulent combustion systems are physically complex processes that involve many interdependent phenomena---including turbulent fluid dynamics, multi-component mass transfer, convective and radiative heat transfer, and multiphase flow---that occur over a wide range of length and time scales. Modeling and simulation studies complement experimental work by implementing and validating models and providing predictive capabilities, but current software tools are often limited by a lack of standardization and best practices, non-robust implementation, or over-specialization. Some topics in combustion CFD research, notably radiative heat transfer and soot modeling, are critically underrepresented in simulation studies as a result of software limitations. This project establishes and …

Assessing The Knowledge, Attitudes, And Practices Of Elementary Teacher Educators On The Inclusion Of Computational Thinking Through Coding, Megan Christine Swanson

Theses and Dissertations

This study sought to understand the knowledge, attitudes, and practices of teacher educators regarding Computational Thinking (CT) and coding. All elementary teacher educators in the state of Utah were sent a survey and asked to participate in a follow up interview. Twentynine faculty replied. Five of the 29 survey respondents were interviewed. Teacher educators shared their definitions of CT and coding, which primarily dealt with problem solving and computer programming, respectively. Overall attitudes were positive about incorporating CT and coding, but many participants questioned how it would fit into the already overwhelming nature of the elementary education major. However, those …

Incorporating Diversity, Equity, And Inclusion Principles Into Our Metadata, Nicole Lewis, Allie Mccormack, Rachel Jane Wittmann

Faculty Publications

This presentation was given as part of the Best of Core Forum Webinar Series.

In early 2021, a group of librarians at two university libraries embarked on a journey to review and update harmful subject headings and other metadata in their catalog, digital library, and finding aids. This session will discuss the background of the project and where the librarians currently stand in the process of remediating these records, including their efforts to create student internships to address problematic language in archival finding aids as well as create a community user advisory group. Special attention will be given to creating …

Potential Local Extirpation Of An Imperiled Freshwater Mussel Population From Wildfire Runoff, Andrew J. Lawrence, Cindy Matuch, Jacquelyn J. Hancock, Andrew L. Rypel, Laura A. Eliassen

Western North American Naturalist

Effects of wildfire and subsequent hydric erosion on freshwater communities are of increasing interest. While freshwater biodiversity is in a global state of decline, examples of climate-driven wildfire impacts to freshwater mussel populations are especially limited. We discovered a population of native floater mussels (Anodonta californiensis/nuttalliana), documented fish species, and recorded data on river substrate characteristics before and after an influx of wildfire runoff in Monterey County, California, USA. Pre-wildfire runoff surveys documented robust and naturally reproducing populations of mussels and 3 species of native fishes (Monterey sucker, Catostomus occidentalis mnioltiltus; Monterey roach, Lavinia symmetricus subditus; …

Computational Studies Of Dinuclear Catalytic Reaction Mechanisms, James Curtis Coombs Iii

Theses and Dissertations

Heterodinuclear and homodinuclear metal complexes with a direct metal-metal interaction offer the potential for unique catalysis due to cooperativity effects that impact reaction mechanisms, reactivity, and selectivity. Quantum-chemical density functional theory (DFT) calculations can directly examine the origin of dinuclear reactivity and selectivity effects. Chapter 1 provides a short overview of heterodinuclear and homodinuclear catalysts that have been experimentally and computationally examined. Chapter 2 reports our study using DFT methods to understand the mechanism and reactivity of a heterodinuclear Co-Zr catalyst with phosphinoamide ligands that catalyzes a Kumada coupling between alkyl halides and alkyl Grignards. Chapter 3 reports DFT calculations …

A Comparison Of Methods Of Rating Creative Writing: A Many-Facets Rasch And User Experience Analysis, Alicia Mcintire

Theses and Dissertations

The use of analytic rubrics remains popular in the field of writing assessment. Previous work in second-language writing assessment and other fields like economics suggest that ratings produced using this method may have lower reliability on average than other methods. Currently, there is little research on the reliability of ratings of creative writing, specifically creative writing authored by adults. This study evaluated the reliability of ratings from an analytic rubric against those produced by a comparative method called Randomly Distributed Comparative Judgment and the rater experience of the methods. The author administered a science fiction and fantasy contest in which …

Core Microbiome To Fingerprint Dust Emission Sources Across The Western United States Of America, Detiare Lisa Leifi

Theses and Dissertations

Over the past century, dust emissions have increased in frequency and intensity due to anthropogenic influences and extended droughts. Dust transports microbes, nutrients, heavy metals and other materials that may then change the biogeochemistry of the receiving environments. The purpose of this study was to find whether unique bacterial communities may provide distinct fingerprints of dust sources in the Western USA. We collaborated with the National Wind Erosion Research Network (NWERN) to identify bacterial core communities (core) of dust from ten NWERN sites, and compared communities to location, soil, and regional characteristics. In order of importance, precipitation levels (F = …

Developing An Accurate Simulation Model For Predicting Friction Stir Welding Processes In 2219 Aluminum Alloy, Kennen Brooks

Theses and Dissertations

Modeling of friction stir welding (FSW) is challenging, as there are large gradients in both strain rate and temperature that must be accounted for in the constitutive law of the material being joined. Constitutive laws are most often calibrated using flow stresses from hot compression or hot torsion testing, where strain rates are much lower than those of the FSW process. As such, the current work employed a recently developed method to measure flow stresses in AA 2219-T67 at the high strain rates typical of FSW. These data were used in the development of a finite element simulation of FSW …

The Effect Of Gut Microbiota On Overwintering Success In Mule Deer, Emma Wilcox

Theses and Dissertations

Mule deer are an important rangeland grazer, large prey species, and game animal for the state of Utah, so herd size is monitored and managed actively. A significant cause of population decline is poor overwintering survival, including from the lack of available forage during winter months. Mule deer energy storage is correlated with greater overwintering success, so physical estimates of energy storage including body condition score (BCS), rump fat (RF), and loin thickness (LT), can be used to track and predict a herd's health. Current methods of collecting deer information are costly, time consuming, and cause physical stress to deer, …

Wildfire Modeling With Data Assimilation, Andrew Johnston

Theses and Dissertations

Wildfire modeling is a complex, computationally costly endeavor, but with droughts worsening and fires burning across the western United States, obtaining accurate wildfire predictions is more important than ever. In this paper, we present a novel approach to wildfire modeling using data assimiliation. We model wildfire spread with a modification of the partial differential equation model described by Mandel et al. in their 2008 paper. Specifically, we replace some constant parameter values with geospatial functions of fuel type. We combine deep learning and remote sensing to obtain real-time data for the model and employ the Nelder-Mead method to recover optimal …

Advanced Isogeometric Discretization Techniques, Kyle Dennis Richardson

Theses and Dissertations

In this dissertation, I provide a robust, efficient inverse mapping algorithm for use in immersed simulation methods, specifically in the Flex Representation Method. I also explore a structural theory that unifies the theories of solids, shells, beams, and rigid bodies. As part of this, I preform a preliminary exploration of applying the Flex Representation Method to shells. Finally, I explore why higher order elements suffer from small critical time steps in explicit dynamics. I then propose a simple method of remedying this issue by exploiting the properties of U-splines.

Determining Figure Skating Jump Under-Rotation In Real-Time Using Imu Sensors During Practice, Duncan O. Furgeson

Theses and Dissertations

We explore the use of machine learning to detect under-rotation in figure skating jumps. Under- rotation in jumps is difficult for the skater to sense but learning to recognize under-rotation is an impor- tant part of learning proper jump technique. To address this difficulty, we present the Under-rotation Monitor, or UR Monitor, a system for detecting under-rotated figure skating jumps in real-time. UR Monitor uses a single inertial measurement unit (IMU) attached to the skater's waist that sends a stream of accelerometer and gyroscope data to a mobile phone via Bluetooth. The mobile phone creates and sends an input vector …

The Cholera-Fiend: Cheap Fiction, Medical Professionals, And Entertainment, Sariah Fales Harrington

Theses and Dissertations

First published in 1849, Charles Averill’s The Cholera-Fiend follows three villains as they attempt to artificially propagate cholera for their own villainous purposes in New York City. Gumbo, a Black servant to one of the villains, is meant to be the humorous relief in the text, but Gumbo experiences a calculated dehumanization from human to disabled, which causes him to be more at-risk for a health crisis—such as a tapeworm or cholera—than his white counterparts. Through analyzing the genre of cheap fiction, the views of medical professionals towards Black bodies, and other ways Black bodies were used as entertainment, I …

Retention Forces For Drops On Microstructured Superhydrophobic Surfaces, Shaur Humayun, R. Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

Accurate models of retention forces between drops and superhydrophobic (SH) surfaces are required to predict drop dynamics on the surface. This retention force is, in turn, useful in modeling heat transfer rates for dropwise condensation on a SH surface. Drop contact angle distribution and base area on SH surfaces are essential factors for predicting retention forces. The present work measures the contact angle distribution and base area shapes of various drop sizes over a wide range of solid fraction for inclined microstructured SH surfaces at the point of drop departure. Base area shape was found to be well approximated using …

Temporal Fluency In L2 Self-Assessments: A Cross-Linguistic Study Of Spanish, Portuguese, And French, Mandy Case

Theses and Dissertations

The present study explores the relationship between temporal fluency and second language (L2) learners' self-assessed and externally assessed proficiency level across the target languages French, Spanish, and Portuguese. Temporal fluency is operationalized as articulation rate (the speed of speech), the mean length of utterance, and the silent pause frequency. Participants (n = 283) in this study are native English speakers enrolled in upper-division language courses at Brigham Young University (BYU). Each participant completed both a self-assessment (the Language Ability Self-Evaluation Resource or LASER) as well as the Computerized Oral Proficiency Interview (OPIc) to receive an external proficiency assessment. Temporal fluency …

Parametric Structural Optimization Of A Wheel Using The Flex Representation Method, Gregory John Vernon

Theses and Dissertations

The use of the finite element method within an optimization workflow is fraught with challenges that limit the automation of such workflows. These challenges are inherent to the traditional finite element formulations which are heavily dependent on a manual meshing process that introduces variability that is challenging to account for within an automated workflow. The recently developed flex representation method (FRM) provides a salient solution to the manual meshing process without sacrificing solution accuracy. In response to the development of FRM a global automotive company requested a study to explore the applicability of FRM to one of their sizing-optimization problems: …

Biofilm Characterization And The Potential Role Of Edna In Horizontal Gene Transfer In Hospital And Meat Isolates Of Staphylococcus Aureus And Their Biofilms, Ashley Lynne Ball

Theses and Dissertations

Staphylococcus aureus is a pathogen responsible for a wide variety of life-threatening diseases such as bacteremia, endocarditis, and pneumoniae. S. aureus has been a major concern in recent years due to the rampant spread of antibiotic resistance. The ability of S. aureus to form biofilms aids in the spread of antibiotic resistance as biofilms are a known hotspot for horizontal gene transfer. Biofilms also protect cells from host immune responses and antibiotics, making these infections very difficult to treat. The matrix of S. aureus biofilms can be made of polysaccharides, protein, and DNA. In these studies, we sought to elucidate …

Methemoglobin Formation Via Nitric Oxide And Comparison Of Methemoglobin, Deoxyhemoglobin, And Ferrous Nitrosyl Hemoglobin As Potential Mri Contrast Agents, Roya Ayati

Theses and Dissertations

Gadolinium-based contrast agents (GBCAs) are in widespread use to enhance magnetic resonance angiography images for evaluating vascular pathology. However, there are safety concerns and limitations regarding the use of GBCAs. It has been shown that the magnetic resonance imaging (MRI) signal intensity (T1-weighted images) in some of the brain's tissues is higher for patients who had multiple exposures to GBCAs compared to patients who had never had exposure to GBCAs. This implies that GBCAs are not sufficiently removed from body such that GBCAs may potentially have long-term effects on the human body. These potential safety concerns have led to an …