Physical Sciences and Mathematics Commons^™

Zeros Of A Family Of Complex-Valued Harmonic Rational Functions, Alexander Lee

Theses and Dissertations

The Fundamental Theorem of Algebra is a useful tool in determining the number of zeros of complex-valued polynomials and rational functions. It does not, however, apply to complex-valued harmonic polynomials and rational functions generally. In this thesis, we determine behaviors of the family of complex-valued harmonic functions $f_{c}(z) = z^{n} + \frac{c}{\overline{z}^{k}} - 1$ that defy intuition for analytic polynomials. We first determine the sum of the orders of zeros by using the harmonic analogue of Rouch\'e's Theorem. We then determine useful geometry of the critical curve and its image in order to count winding numbers by applying the harmonic …

Single-Shot, Ultrafast, Multi-Frame X-Ray Imaging Of Defect-Bearing Ablator Materials In Extreme Conditions, Daniel S. Hodge

Theses and Dissertations

Characterization of the dynamic behavior of defect-bearing ablator materials subjected to extreme conditions is essential in advancing fusion energy as an reliable and abundant energy source. By understanding how materials evolve spatially and temporally we can minimize hydrodynamic instabilities, which are major contributing factors to energy yield degradation in inertial confinement fusion (ICF) experiments. In this thesis we demonstrate the capabilities of an ultrafast x-ray imaging (UXI) detector, the Icarus V2, where we capture multiple frames of single void-bearing sample compressed by a high-intensity laser shockwave. Using the Matter in Extreme Conditions (MEC) instrument at the Linac Coherent Light Source …

Identity Work To Teach Mathematics For Social Justice, Navy B. Dixon

Theses and Dissertations

In this thesis, mathematics educators are conceptualized as individuals with multiple, simultaneous figured worlds that inform their decisions while planning. The study explores how two mathematics educators negotiated and orchestrated their figured worlds to plan two mathematics lessons for social justice. The results highlight how numerous the figured worlds each participant surfaced through background interviews. Some of the figured worlds were elicited by the interview questions (i.e., Race, Family, Social Justice Teaching) but other figured worlds organically surfaced through the interviews (i.e., Sexuality, Community, Activism, Critical Information Consumption). A discursive analysis of a selection of these figured worlds revealed conceptualizations …

Improving Spatial Resolution Of Time Reversal Focusing Using Arrays Of Acoustic Resonators, Adam David Kingsley

Theses and Dissertations

Using a near-field array of acoustic resonators, it is possible to modify a focused pressure field and enforce a spatial frequency corresponding to the resonator array spacing. This higher spatial frequency makes it possible to focus and image with a resolution that is better than if the focusing were in free space. This near-field effect is caused by the phase shifting properties of resonators and, specifically, the delayed phase found in waves with a temporal frequency lower than that of the resonators in the array. Using time reversal, arrays of resonators are explored and the subwavelength focusing is used to …

Focusing Of High-Amplitude Sound Waves Using The Time Reversal Process, Brian D. Patchett

Theses and Dissertations

Time reversal is a method often used to focus sound to a desired location, and works best in a reverberant environment. The effect of focus location within a reverberant environment is presented first, revealing that proximity to reflecting surfaces has a significant effect on the amplitude of the focus both experimentally and when using a modal summation model. These effects are a primary component to creating focus signals at high amplitudes. High-amplitude focusing experiments show that when multiple sources are used simultaneously to generate a focus, a peak amplitude pressure spike of 200 dB can be achieved in air. A …

Facies Architecture And Provenance Of The Highly Progradational, Fluvial Dominated Deltaic Depositional System Of The Cretaceous Nanushuk Formation On The North Slope Of Alaska, Sarah N. Naone

Theses and Dissertations

The Cretaceous Nanushuk Formation of northern Alaska records extremely rapid shoreline progradation across the Colville Basin during the Albian-Cenomanian epochs. Additionally, it records a period of tectonic realignment in the region, as the main sediment source began to transition from the Chukotkan orogeny to the west to a more local sediment source of the proximal Brooks Range to the south. Through detailed outcrop characterization and 3-D modeling of three exposed outcrops along the axial trend of the Colville Basin on the North Slope and the Upper section of the Nanushuk, this study clarifies the relative timing of the early Brookian …

Methods For Single-Cell And Low-Input Proteomics, Yiran Liang

Theses and Dissertations

Single-Cell Proteomics (SCP) can provide unique insights into biological processes by resolving heterogeneity that is obscured by bulk measurements. Gains in the overall sensitivity and proteome coverage through improvements in sample processing and analysis increase the information content obtained from each cell, particularly for less abundant proteins. In addition to achieving in-depth proteome coverage from single cells, higher throughput measurements enable large-scale and statistically significant features within single cell populations. This dissertation focuses on method development to improve the sensitivity and throughput of SCP based on the nanoPOTS (nanodroplet Processing in One pot for Trace Samples) platform. The methods discussed …

Reservoir Computing Solutions For Streamflow Modeling And Prediction In Real World Scenarios, Paden Allsup

Undergraduate Honors Theses

With severe drought continuing in the western United States and the effects of climate change becoming more apparent across the world, it is becoming increasingly important to be able to predict the impact of extreme weather events like storms, droughts, and fires on streamflow dynamics. This includes flow regime as well as biogeochemical behavior of river systems and their watersheds. This project explores the use of Echo State Networks (ESN), a subset of Reservoir Computing, on modeling and predicting streamflow variability with a focus on biogeochemical patterns. In this project ESNs are tested and compared in the hope of creating …

Evaluating Multi-Agent Modeller Representations, Jonathan Demke

Theses and Dissertations

The way a multi-agent modeller represents an agent not only affects its ability to reason about agents but also the interpretability of its representation space as well as its efficacy on future downstream tasks. We utilize and repurpose metrics from the field of representation learning to specifically analyze and compare multi-agent modellers that build real-valued vector representations of the agents they model. By generating two datasets and analyzing the representations of multiple LSTM- or transformer-based modellers with various embedding sizes, we demonstrate that representation metrics provide a more complete and nuanced picture of a modeller's representation space than an analysis …

Design And Evaluation Of Miniaturized Ion Trap Mass Analyzers Using Simulation, Radhya Weligama Gamage

Theses and Dissertations

Mass spectrometry is a technique that analyzes the chemical compositions of compounds based on the mass-to-charge ratio of their ionized constituents. Miniaturized ion trap mass spectrometry finds application in a wide range of fields where portable, rugged, and reliable analytical instruments are required. Ion traps of various designs have been introduced over the past decades, each with their own unique advantages and capabilities. However, the process of developing a novel miniaturized ion trap mass spectrometer continues to be fraught with challenges. This dissertation discusses simulation studies pertaining to the development of a novel dual ion trap, the simplified coaxial ion …

Stemficohort1preinterviewdata, Rebecca L. Sansom, Bryn Stclair, Jamie Jensen, Richard West

ScholarsArchive Data

The science, technology, engineering, and mathematics faculty institute (STEMFI) is a National Science Foundation funded project designed to provide support, measurement, and training to BYU faculty developing their own student-centered curriculum.

This PDF file contains pre-institute participation interview data from the first cohort of faculty involved in the STEM faculty institute (2018).

Charge Detection Mass Spectrometry Using Printed Circuit Board Arrays For The Analysis Of Microparticles In The Martian Atmosphere, Elaura Luanne Gustafson

Theses and Dissertations

Charge detection mass spectrometry (CDMS) is a single particle technique capable of simultaneously measuring charge and mass-to-charge ratios for individual ions or particles. The linear array CDMS design theoretically has no upper mass limit and is therefore a choice method for the analysis of high mass and heterogeneous samples, such as dust microparticles in the Martian atmosphere. This dissertation describes the development of a novel charge detection mass spectrometer made of printed circuit boards (PCB) for the analysis of dust microparticles in the Martian atmosphere. Development of this device has required investigations in analysis methods and the engineering design of …

An Analog For Large-Scale Lacustrine Deposits: 3d Characterization Of A Pleistocene Lake Bonneville Spit, Eli D. Lopez

Theses and Dissertations

Ultra-high-resolution subsurface stratigraphy mapped from 3D ground-penetrating radar (GPR) can provide insights into the fine-scale heterogeneity of reservoirs and other geologic features. Analog models derived from 3D GPR aid in understanding reservoir compartmentalization that may be sub-seismic but still affect fluid flow. We integrate 2D profiles and 3D GPR volumes with measured stratigraphic sections from outcrop exposure to characterize the fine-scale stratigraphy of an ancient Lake Bonneville shoreline deposit (locally, circa 20 ka based on carbon-14 dating) in the Great Basin (northwestern Utah). The heterogeneity of the deposit is expressed as multiple discordant patterns, separated by unconformities that likely were …

Air Quality Impacts From Mineral Dust, Fireworks, And Urban Pollution Revealed By Trace Element Chemistry And Strontium Isotopes Ratios In The Wasatch Front, Utah, Usa, Micah J. Marcy

Theses and Dissertations

Airborne particulate matter (PM) in urban areas is derived from a combination of natural and anthropogenic sources. To identify PM sources and their effects on air quality, we collected PM using active filter samplers over a two-year period in the urban Wasatch Front, northern Utah, an area affected by multiple pollution sources. Filters from active samplers and other PM samples were analyzed for major and trace element concentrations and 87Sr/86Sr ratios. We identified wind-blown mineral dust from dry lake beds, winter inversions, and fireworks as primary PM sources affecting air quality in the Wasatch Front. Dust contributes Al, Be, Ca, …

Still No Crystal Ball: Toward An Application For Broad Evaluation Of Student Understanding, Piper Armstrong

Theses and Dissertations

Evaluation of student understanding of learning material is critical to effective teaching. Current computer-aided evaluation tools exist, such as Computer Adaptive Testing (CAT); however, they require expert knowledge to implement and update. We propose a novel task, to create an evaluation tool that can predict student performance (knowledge) based on general performance on test questions without expert curation of the questions or expert understanding of the evaluation tool. We implement two methods for creating such a tool, find both methods lacking, and urge further investigation.

Synthesis And Anticancer Evaluation Of Novel Pyrazolo[1,5-A]Pyrimidines: Discovery Of A Novel Lead Compound With Selective Activities Against Vps34 And Jak1-Jh2 Pseudokinase, Reuben Dass

Theses and Dissertations

A library of 25 novel 3,6-disubstituted and 3-substituted pyrazolo[1,5-a]pyrimidines were synthesized using a microwave chemical reactor in 3 steps with a total reaction time of 1 hour. The products were obtained in good to excellent yields (20-93%, ave. = 62%). The synthesis began with the reaction of aryl acetonitriles with dimethylformamide-dimethylacetal (120C, 20 min), followed by treatment of the resulting 2-arylacrylonitrile with H2NNH2 • HBr (120C, 20 min). The intermediate 4-arylpyrazol-5-amine obtained was finally reacted with either 2-aryl-substituted malondialdehydes or 1,1,3,3-tetramethoxypropane (120C, 20 min) to give the final products. The products were either collected directly on a Buchner funnel or …

Yardang Morphometry And Substrate Properties In Ignimbrites Of The Campo Piedra Pomez, Argentina Compared With The Medusae Fossae Formation, Mars, Dylan Stephen Mcdougall

Theses and Dissertations

Yardangs are streamlined ridges carved by the action of wind into consolidated yet erodible substrates. The direction of sediment transport is indicated by their elongate shapes and steep sides which redirects most of the sediment transport layer onto adjacent low-lying surfaces, resulting in lower erosion rates on the elevated areas. Despite this simple premise, the rates of erosion and transport as well as the material properties necessary to form yardangs have until now been largely unknown. This study aims to determine how material properties affect yardang dimensions in order to use yardang morphometry to derive the mechanical properties of a …

Multiscale Modeling And Analysis Of X-Ray Windows, Microcantilevers, And Bioimpedance Microelectrodes, Kyle Grant Larsen

Theses and Dissertations

X-ray detector windows must be thin enough to transmit sufficient low-energy x-rays, yet strong enough to withstand up to an atmosphere of differential pressure. Traditional low-energy x-ray windows consist of a support layer and pressure membrane spanning that support. Numerical modeling of several x-ray windows was used to show that both low- and high-energy x-ray transmission can be improved by adding a secondary support structure. Finite element analysis of the x-ray window models showed that the stress from a typical applied load does not exceed the ultimate strength or yield strength of the respective materials. The specific x-ray window models …

Examination Of 14-3-3 Interactors Identifies A Novel Mechanism Of Regulation For The Ubiquitin Binding Kinase Tnk1 That Can Be Targeted To Block Tumor Growth, Christina Marie Egbert

Theses and Dissertations

Decades of research have begun to identify oncogenic mut-drivers that are responsible for driving a large percentage of cancers. These high frequency mut-drivers have therapeutics in the clinic for patient treatment. However, there is another group of low frequency mut-drivers that fail to rise above the noise of the high frequently drivers. These low frequency drivers represent a group of genes with untapped potential for new targeted therapies. However, identifying these drivers can be difficult. This study focuses on identifying new functional phosphorylations using the phospho-docking protein 14-3-3. The family of 14-3-3 proteins have been linked to many oncogenic pathways …

Leveraging Large Language Models Trained On Code For Symbol Binding, Joshua Robinson

Theses and Dissertations

While large language models like GPT-3 have achieved impressive results in the zero-, one-, and few-shot settings, they still significantly underperform on some tasks relative to the state of the art (SOTA). For many tasks it would be useful to have answer options explicitly listed out in a multiple choice format, decreasing computational cost and allowing the model to reason about the relative merits of possible answers. We argue that the reason this hasn't helped models like GPT-3 close the gap with the SOTA is that these models struggle with symbol binding - associating each answer option with a symbol …

Measuring Nonlinear Thomson Scattering At Arbitrary Emission Angles, Mahonri Romero Carranza

Theses and Dissertations

We use photon-counting to measure nonlinear Thomson scattering from low-density electrons in an intense laser focus. The azimuthal and longitudinal polarization components of the second harmonic are measured across much of the full emission sphere. The data show, for the first time experimentally, emission structure in the ‘Northern’ and ‘Southern’ hemispheres, where the ‘North Pole’ aligns with the direction of laser propagation. To obtain these measurements, we installed an additional power amplifier on our Ti:sapphire laser system at BYU. The upgrade delivers ten times more energy to the laser focus than we had previously. This increase comes partly from the …

Distribution And Transportation Of Sand And Potential Sand Source Materials On Titan: Implications For The Geologic History, Benjamin Dean Lake

Theses and Dissertations

Titan is an important planetary body for aeolian research because of the vast equatorial sand seas that span 20% of its surface. Previous studies have determined the general margins of sand and sand seas on Titan, and have speculated about the source of Titan's sand. Little research has been done concerning where sand collects in the sand seas. Additionally, the relationships be-tween material distributions as observed by the Cassini Visual and Infrared Mapping Spectrometer (VIMS) and the history of erosion and transportation of sediments across equatorial latitudes is not fully understood. This work focuses on an in depth evaluation of …

Design And Characterization Of A Miniaturized Spectrometer For Wearable Applications, Tyler Richard Westover

Theses and Dissertations

As individual health monitors continue to become more widely adopted in helping individuals make informed decisions, new technologies need to be developed to obtain more biometric data. Spectroscopy is a well-known tool to gain biological information. Traditionally spectrometers are large and expensive making personal or wearable health monitors difficult. Here we present the development and characterization of a miniaturized short wavelength infrared spectrometer for wearable applications. We present a carbon nanotube parallel hole collimator can effectively select a narrow set of allowed angles of light to be separated by a linear variable filter and detected at a photodiode array making …

Ion Structure Characterization And Energetics In The Gas Phase Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry And Ion Mobility Spectrometry, Tina Heravi

Theses and Dissertations

In this dissertation, I used Fourier transform ion cyclotron resonance mass spectrometry (FTICR) and ion mobility spectrometry (IMS) to study the structure and energetics of supramolecular complex ions in the gas phase. Using the CRAFTI (cross sectional areas by Fourier transform ion cyclotron resonance) technique developed by Dearden’s lab we observed that complexes with alkali cations capping the portals of cucurbit[5]uril (CB[5]) bind halide anions size-selectively in the gas phase. Our data suggest that Cl– binds inside the CB[5] cavity, Br– binds both inside (with Na+ions capping the portals of CB[5]) and outside (when K+caps CB[5]), and I– binds weakly …

Considerations For And Development Of Sound Level Maps For The M16a4 Rifle, Reese D. Rasband

Theses and Dissertations

Small firearms can create sound levels exceeding the safe threshold of human hearing with even one shot. Understanding how the sound propagates will lead to better range and military drill design. This thesis describes errors associated with different predictive interpolation models for the M16A4. Before directly discussing potential sources of error, the thesis first seeks to validate the data acquired. This is done through waveform inspection with a focus on shot-to-shot consistency. Finding the standard deviation in level between a 10-shot volley provides a good baseline with which other sources of error can be compared to. For both peak and …

A Machine Learning Approach That Integrates Clinical Data And Ptm Proteomics Identifies A Mechanism Of Ack1 Activation And Stabilization In Cancer, Eranga Roshan Balasooriya Loku Balasooriyage

Theses and Dissertations

Identification of novel cancer driver mutations is crucial for targeted cancer therapy, yet a difficult task especially for low frequency drivers. To identify cancer driver mutations, we developed a machine learning (ML) model to predict cancer hotspots. Here, we applied the ML program to 32 non-receptor tyrosine kinases (NRTKs) and identified 36 potential cancer driver mutations, with high probability mutations in 10 genes, including ABL1, ABL2, JAK1, JAK3, and ACK1. ACK1 is a member of the poorly understood ACK family of NRTKs that also includes TNK1. Although ACK1 is an established oncogene and high-interest therapeutic target, the exact mechanism of …

Gradient Conditioning In Deep Neural Networks, Michael Vernon Nelson

Theses and Dissertations

When using Stochastic Gradient Descent (SGD) to train Artificial Neural Networks, gradient variance comes from two sources: differences in the weights of the network when each batch gradient is estimated and differences between the input values in each batch. Some architectural traits, like skip-connections and batch-normalization, allow much deeper networks to be trained by reducing each type of variance and improving the conditioning of the network gradient with respect to both the weights and the input. It is still unclear to which degree each property is responsible for these dramatic stability improvements when training deep networks. This thesis summarizes previous …

Understanding The Complexities Of Anemia In Chronic Inflammatory Diseases From Diagnosis To Treatment, Naomi Rae Flindt

Theses and Dissertations

Iron is an essential nutrient for energy and DNA replication. Its homeostasis is commonly perturbed by chronic inflammatory mechanisms. Chronic inflammation upregulates a cytokine, hepcidin, that degrades the iron export protein ferroportin. Without a way to export iron into the bloodstream iron availability in blood becomes depleted. Iron depletion in the blood stream hinders erythropoiesis and is termed anemia. Herein I investigate and inhibit the mechanism of hepcidin activation. Inhibition of hepcidin activation has released iron from tissues and alleviated anemic conditions in a cancer model. I have laid the foundation to investigate this pathway in a 3D spheroid model. …

Mirror Symmetry For Some Non-Abelian Groups, Kyle John Niendorf

Theses and Dissertations

The goal of this thesis is to investigate a conjecture about Mirror Symmetry for Landau Ginzburg (LG) models with non-abelian gauge groups. The conjecture predicts that the LG A-model for a polynomial-group pair $(W,G)$ is equivalent to the LG B-model for the dual pair $(W^*, G^*)$. In particular, the A-model and B-model include the construction of a Frobenius algebra. The LG mirror symmetry conjecture predicts that the A-model Frobenius algebra for $(W,G)$ will be isomorphic to the B-model Frobenius algebra for the dual pair $(W^*,G^*)$. Part of the conjecture includes a rule describing how to construct the dual pair. Until …

Student-Created Learning Objects For Mathematics Renewable Assignments: The Potential Value They Bring To The Broader Community, Webster Wong

Theses and Dissertations

Having students create Learning Objects (LOs) through renewable assignments has proved more helpful to the student creators compared to disposable assignments in some aspects. Additionally, some researchers have presented evidence where the student-created LOs could benefit the users of the LOs more than traditional learning resources. In this study, I examined a collection of LOs created by college students in the subject of mathematics to understand the nature of the value that a student-created LO could bring to other learners. By extending a framework for non-disposable assignments (Seraphin et al., 2019), I evaluated 3 components that affect the value of …