Physical Sciences and Mathematics Commons^™

Tabletop Extreme-Ultraviolet Source Using High Harmonic Generation For Polarization Sensitive Imaging, Taylor Jordan Buckway

Theses and Dissertations

We are developing a tabletop extreme-ultraviolet source using high harmonic generation at Brigham Young University. The thesis goes over the theory of high harmonic generation using the three-step model. This tabletop source was designed for probing magnetic domains of iron nanoparticles. We present optimization of the 42 eV and 52 eV harmonics through phase matching. Phase matching consists of tuning the intensity of the IR beam and pressure of the gas medium. The target gas medium used for this thesis is argon. The 42 eV harmonic was optimized to 8.2 billion photons per second. This was used with a 1500 …

Network Specialization: A Topological Mechanism For The Emergence Of Cluster Synchronization, Ethan Walker

Theses and Dissertations

Real-world networks are dynamic in that both the state of the network components and the structure of the network (topology) change over time. Most studies regarding network evolution consider either one or the other of these types of network processes. Here we consider the interplay of the two, specifically, we consider how changes in network structure effect the dynamics of the network components. To model the growth of a network we use the specialization model known to produce many of the well-known features observed in real-world networks. We show that specialization results in a nontrivial equitable partition of the network …

Characterizing Equivalence And Correctness Properties Of Dynamic Mode Decomposition And Subspace Identification Algorithms, Samuel Gregory Neff

Theses and Dissertations

We examine the related nature of two identification algorithms, subspace identification (SID) and Dynamic Mode Decomposition (DMD), and their correctness properties over a broad range of problems. This investigation begins by noting the strong relationship between the two algorithms, both drawing significantly on the pseudoinverse calculation using singular value decomposition, and ultimately revealing that DMD can be viewed as a substep of SID. We then perform extensive computational studies, characterizing the performance of SID on problems of various model orders and noise levels. Specifically, we generate 10,000 random systems for each model order and noise level, calculating the average identification …

Accurate Band Energies Of Metals With Quadratic Integration, Jeremy John Jorgensen

Theses and Dissertations

Materials play an important role in society. Historically, and even at present, materials have been discovered by trial and error, and many of the most useful materials have been discovered by chance. The high-throughput approach aims to remove (as much as possible) chance and guesswork at the experimental level by filtering out materials candidates that are not predicted to exist. Many successes have been recorded. In the high-throughput approach to materials discovery, machined-learned models of materials are created from databases of theoretical materials. These databases are the result of millions of density-functional-theory (DFT) simulations. The size and accuracy of the …

How Failures Cascade In Software Systems, Barbara W. Chamberlin

Theses and Dissertations

Cascading failures involve a failure in one system component that triggers failures in successive system components, potentially leading to system wide failures. While frequently used fault tolerant techniques can reduce the severity and the frequency of such failures, they continue to occur in practice. To better understand how failures cascade, we have conducted a qualitative analysis of 55 cascading failures, described in 26 publicly available incident reports. Through this analysis we have identified 16 types of cascading mechanisms (organized into eight categories) that capture the nature of the system interactions that contribute to cascading failures. We also discuss three themes …

The Perception Of At-Risk Students On Caring Student-Teacher Relationships And Its Impact On Their Productive Disposition, Brittany Hopper

Theses and Dissertations

The importance of a positive, caring relationship with students in the classroom is under-researched in mathematics education. Research shows that a positive student-teacher relationship can have many long-term positive results for the student. Many of these results directly impact a student's productive disposition towards mathematics. At-risk students are in greater need of positive relationships and an increase in productive disposition. Using Joan Tronto's (1993) elements of care, I examine the student perspective of these kinds of relationships and how the student sees development of their own productive disposition.

A Permutation-Based Confidence Distribution For Rare-Event Meta-Analysis, Travis Andersen

Theses and Dissertations

Confidence distributions (CDs), which provide evidence across all levels of significance, are receiving increasing attention, especially in meta-analysis. Meta-analyses allow independent study results to be combined to produce one overall conclusion and are particularly useful in public health and medicine. For studies with binary outcomes that are rare, many traditional meta-analysis methods often fail (Sutton et al. 2002; Efthimiou 2018; Liu et al. 2018; Liu 2019; Hunter and Schmidt 2000; Kontopantelis et al. 2013). Zabriskie et al. (2021b) develop a permutation-based method to analyze such data when study treatment effects vary beyond what is expected by chance. In this work, …

A Multidimensional Convolutional Bootstrapping Method For The Analysis Of Degradation Data, Jared M. Clark

Theses and Dissertations

While Monte Carlo methods for bootstrapping are typically easy to implement, they can be quite time intensive. This work aims to extend an established convolutional method of bootstrapping to work when convolutions in two or more dimensions are required. The convolutional method relies on efficient computational tools rather than Monte Carlo simulation which can greatly reduce the computation time. The proposed method is particularly well suited for the analysis of degradation data when the data are not collected on time intervals of equal length. The convolutional bootstrapping method is typically much faster than the Monte Carlo bootstrap and can be …

Inhibition Of Cell Adhesion And Actin Localization During Migration Upon Protective Antigen Mutant Ligand Binding To The Capillary Morphogenesis Gene 2, Sai Lun Lee

Theses and Dissertations

Capillary Morphogenesis Gene 2 protein (CMG2) is a type 1 transmembrane receptor known as the anthrax toxin receptor 2 (ANTXR2). While it is documented that the cell surface receptor CMG2 mediates anthrax toxin entry into the cell via endocytosis, the physiological role of CMG2 is not well understood. Others have suggested that CMG2 may have a role in mediating ECM homeostasis and angiogenesis. Additionally, both anthrax protective antigen (PA) and a furin protease-resistant mutant, PASSSR, inhibit corneal neovascularization in a mouse model, and interestingly PASSSR has a greater affinity to CMG2 receptor. PASSSRalso has a more potent antiangiogenic effect than …

Physics-Guided Machine Learning In Ocean Acoustics Using Fisher Information, Michael Craig Mortenson

Theses and Dissertations

Waterborne acoustic signals carry information about the ocean environment. Ocean geoacoustic inversion is the task of estimating environmental parameters from received acoustic signals by matching the measured sound with the predictions of a physics-based model. A lower bound on the uncertainty associated with environmental parameter estimates, the Cramér-Rao bound, can be calculated from the Fisher information, which is dependent on derivatives of a physics-based model. Physics-based preconditioners circumvent the need for variable step sizes when computing numerical derivatives. This work explores the feasibility of using a neural network to perform geoacoustic inversion for environmental parameters and their associated uncertainties from …

“If I Could Do This, I Feel Anyone Could:” The Design And Evaluation Of A Two-Factor Authentication Manager, Garrett D. Smith

Theses and Dissertations

Two-factor authentication (2FA) is a strong defense against account compromise. However, usability studies reveal challenges with 2FA setup. The process to manually setup and remove 2FA methods differs across websites. We present a system design for a 2FA manager to automatically setup and remove 2FA methods. Potential benefits are reduced time, fewer mistakes, consistent terminology, a single workflow for users to learn, and the ability to rapidly transition to a new 2FA method—e.g., when replacing a lost 2FA method. We create two proof-of-concept implementations of our design, one as a browser extension and one integrated as a feature in an …

The Novel Protein Crystallization Chaperone Telsam Stabilizes Weak Crystal Contacts, Accelerates Crystallization Of Fused Target Proteins, And Solves The Crystallographic Phase Problem, Supeshala Dilrukshi Sarath Nawarathnage

Theses and Dissertations

We studied the usefulness of genetic fusion to TELSAM polymers as an effective protein crystallization strategy. We observed novel properties in crystals of two TELSAM-target protein fusions. TELSAM as a crystallization chaperone shows rapid crystallization when it's fused to target proteins and possibly with a greater propensity. Some TELSAM-target fusions crystallized more rapidly than the same target protein alone. TELSAM-target proteins can be crystallized at relatively low protein concentrations such as 0.1 mg/mL. TELSAM requires no TELSAM polymers touching one another in the crystal lattice in order to form well-diffracting crystals. This lack of crystal contacts has not been observed …

Using Connections To Make Predictions On Dynamic Networks, Rebecca Dorff Jones

Theses and Dissertations

Networks are sets of objects that are connected in some way and appear abundantly in nature, sociology, and technology. For many centuries, network theory focused on static networks, which are networks that do not change. However, since all networks transform over time, static networks have limited applications. By comparison, dynamic networks model how connections between objects change over time. In this work, we will explore how connections in dynamic networks change and how we can leverage these changes to make predictions about future iterations of networks. We will do this by first considering the link prediction problem, using either Katz …

Statistical Properties Of 2d Navier-Stokes Equations Driven By Quasi-Periodic Force And Degenerate Noise, Rongchang Liu

Theses and Dissertations

We consider the incompressible 2D Navier-Stokes equations on the torus driven by a deterministic time quasi-periodic force and a noise that is white in time and extremely degenerate in Fourier space. We show that the asymptotic statistical behavior is characterized by a uniquely ergodic and exponentially mixing quasi-periodic invariant measure. The result is true for any value of the viscosity ν > 0. By utilizing this quasi-periodic invariant measure, we show the strong law of large numbers and central limit theorem for the continuous time inhomogeneous solution processes. Estimates of the corresponding rate of convergence are also obtained, which is the …

Stabilizing Controlled Systems In The Presence Of Time-Delays, Isaac Becker Pardo

Theses and Dissertations

A dynamical system's state evolves over time, and when the system stays near a particular state this state is known as a stable state of the system. Through control methods, dynamical systems can be manipulated such that virtually any state can be made stable. Although most real systems evolve continuously in time the application of digital control methods to these systems is inherently discrete. States are sampled (with sensors) and fed back into the system in discrete-time to determine the input needed to control the continuous system. Additionally, dynamical systems often experience time delays. Some examples of time delays are …

Computationally Assisted Nmr Crystallography: A Path To Unusually High-Resolution Crystal Structures, Luther Wang

Theses and Dissertations

Crystallography has traditionally been studied by diffraction methods involving X ray or neutron radiation. These methods have some limitations, from requiring the substance under study to form single crystals to the limited ability of X rays to locate hydrogen atoms. While neutron radiation can characterize hydrogens, it is expensive, not readily available and has its own particular limits on resolution. It this dissertation, it is demonstrated that NMR is extraordinarily sensitive to atomic positions, with variations of mere tens of femtometers creating statistically distinguishable chemical shift changes. To date, no other means of measurement can detect structural changes at this …

Gas Phase Structure Characterization Of Host-Guest Systems Using Ion Mobility Spectrometry, Jamir Shrestha

Theses and Dissertations

This dissertation focuses on the investigation of gas-phase characteristics of cucurbituril host-guest systems using ion mobility spectrometry (IMS) and related techniques. Collision cross-sections (CCS) of alkylammonium complexes of cucurbit[n]uril (CB[n]) are measured to understand the allosteric interactions that induce conformational changes in the complex in the presence of metal cations on one of the portals of the cucurbit[6]uril (CB[6]) host. Cationic species on one CB[6] rim sterically force longer linear alkylammonium guests out of the cucurbituril cavity during complex formation. Similarly, rigid cucurbituril-metal complexes were studied using IMS to demonstrate the effect of long-range ion-neutral interactions on the gas phase …

Developing The Next Generation Of Heterogeneous Catalysts: Metal-Organic Framework Thin Films And Their Derivatives, Hans Christian Anderson

Theses and Dissertations

Metal-Organic Frameworks (MOFs) are an important class of materials that are gaining increasing relevance for many fields including energy storage, CO2 capture, photovoltaics, and catalysis. MOF mediated synthesis (MOFMS) is the decomposition of a MOF to form an amorphous carbon material decorated with metal nanoparticles. MOF thin films are an area where MOFMS has not been thoroughly explored, yet they are likely to be industrially relevant due to their potential application as highly dispersed, sinter resistant supported catalysts. In this work, we have developed a method for the growth of copper- and zinc-based MOF thin films on silicon- and aluminum- …

Atg9a And Atg13 Cooperate To Drive Basal Autophagy, Daniel Morgan Poole

Theses and Dissertations

Autophagy, as the name suggests, is a cellular process of self-eating in which cytoplasmic debris is engulfed by a double membrane vesicle dubbed the autophagosome and is ultimately degraded and recycled by proteases in the lysosome. The process is initiated by a group of core ATG proteins, including a multi-pass transmembrane protein called ATG9A. Although ATG9A has been shown to be essential for both stress induced and basal autophagy, its mechanism and interaction network remain largely illusive. Our current study employs BioID proteomics to identify a network of interactors, including regulators of membrane fusion and vesicle trafficking, such as TRAPP, …

Musical Phrase Segmentation Via Grammatical Induction, Reed James Perkins

Theses and Dissertations

Procedural generation algorithms can infer rules based on a dataset of examples when each example is made up of labeled components. Unfortunately, musical sequences resist potential inclusion in these kinds of datasets because they lack explicit structural semantics. In order to algorithmically transform a musical sequence into a sequence of labeled components, a segmentation process is needed. We outline a solution to the challenge of musical phrase segmentation that uses grammatical induction algorithms, a class of algorithms which infer a context-free grammar from an input sequence. We study five different grammatical induction algorithms on three different datasets, one of which …

Hybrid Suspension Tissue Engineering Of A 3d Alveolar Model For Lung And Vascular Disease Modeling, Jonard Corpuz Valdoz

Theses and Dissertations

Tissue engineering is a dichotomy of scaffold-based and scaffold-free cultures. Scaffold-based cultures form highly organotypic structures but with low uniformity and throughput. Conversely, scaffold-free cultures create consistently sized and shaped cell aggregates with limited spheroid-like structure and function, thus restricting their use for accurate disease modeling. We hypothesized that combining aspects of each culturing format, we would produce highly organotypic structures of consistent size and shape for use in pulmonary modeling. First, to improve on culture consistency and output, we created a novel easily scalable, minimalistic design for a micropatterned hydrogel dish that increases reliability and efficiency in 3D cell …

Enhancing The Opportunities For Adults With Autism To Find Jobs Using A Job-Matching Algorithm, Joseph T. Bills

Theses and Dissertations

Adults with autism face many difficulties when finding employment, such as struggling with interviews and needing accommodating environments for sensory issues. However, autistic adults also have unique skills to contribute to the workplace that companies have recently started to seek after, such as close attention to detail and trustworthiness. To work around these difficulties and help companies find the talent they are looking for we have developed a job-matching system. Our system is based around the stable matching of the Gale-Shapley algorithm to match autistic adults with employers after estimating how both adults with autism and employers would rank the …

Datadescription-Detection Of Sulfur Dioxide By Broadband Cavity-Enhanced Absorption Spectroscopy (Bbceas), Ryan Thalman, Nitish Bhardwaj, Callum Flowerday, Jaron C. Hansen

ScholarsArchive Data

Files archived include the following:

Figure1.txt This file contains all the data used to make Figure 1 in the paper.

Figure4.txt This file contains all the data used to make Figure 4 in the paper.

Figure5.txt This file contains all the data used to make Figure 5 in the paper.

Figure6.txt This file contains all the data used to make Figure 6 in the paper.

Figure7.txt This file contains the code, written in Igor, that was used to generate this figure.

Figure8.txt This file contains all the data used to make Figure 8 in the paper.

Figure9.txt This file contains …

Identification Of Sources Of Air Pollution Using Novel Analytical Techniques And Instruments, Nitish Bhardwaj

Theses and Dissertations

This dissertation is a collection of studies that investigates the issue of air pollution in the field of environmental chemistry. My thesis consists of research works done to measure the concentration of particulate matter (PM) and gas-phase species in ambient air. High concentrations of PM is a significant problem in Utah and in other regions of the world. Particles having an aerodynamic diameter of 2.5 micrometers and smaller play a crucial role in air pollution and pose serious health risks when inhaled. PM is composed of both organic and inorganic components. The organic fraction in PM ranges from 10-90% of …

Confronting Barriers To Human-Robot Cooperation: Balancing Efficiency And Risk In Machine Behavior, Tim Whiting

Theses and Dissertations

In strategically rich settings in which machines and people do not fully share the same preferences, machines must learn to cooperate and compromise with people to establish mutually successful relationships. However, designing machines that effectively cooperate with people in these settings is difficult due to a variety of technical and psychological challenges. To better understand these challenges, we conducted a series of user studies in which we investigated human-human, robot-robot, and human-robot cooperation in a simple, yet strategically rich, resource-sharing scenario called the Block Dilemma, a game in which players must balance fairness, efficiency, and risk. While both human-human and …

Implementing A High-Performance Quantum Computing Emulator, Reece Robertson

Undergraduate Honors Theses

We implement a quantum computing emulator after the manner described by Häner et al. with the goal of temporal and spatial savings. The emulator is compared to the Intel Quantum Simulator to verify speedup and spatial savings over the simulator method. We also implement Shor's algorithm in the emulator and use it to solve a nontrivial factoring problem. This demonstrates that the emulator makes quantum computing more accessible on at least two accounts: it allows users to solve nontrivial problems quickly and it provides those looking to enter quantum computing with an accessible place to start. Finally, we outline future …

Symbolic Semantic Memory In Transformer Language Models, Robert Kenneth Morain

Theses and Dissertations

This paper demonstrates how transformer language models can be improved by giving them access to relevant structured data extracted from a knowledge base. The knowledge base preparation process and modifications to transformer models are explained. We evaluate these methods on language modeling and question answering tasks. These results show that even simple additional knowledge augmentation leads to a reduction in validation loss by 73%. These methods also significantly outperform common ways of improving language models such as increasing the model size or adding more data.

Polymer Coated Urea Microplastics: Urban Landscape, C. J. Seely, B. T. Geary, B. G. Hopkins

Library/Life Sciences Undergraduate Poster Competition 2022

• Polymer Coated Urea (PCU) is an effective fertilizer.
• Microplastics, from a wide range of waste materials, pollute water bodies.
• One potential source of microplastics are from PCU fertilizers if the coatings are transported overland into water bodies.
• Various urban landscape systems vary in the potential for surface runoff.

Kemar Hats Head Orientation Directivity, Samuel D. Bellows, Timothy W. Leishman

Directivity

This directivity data set for a KEMAR head head-and-torso simulator (HATS) includes head orientations in 14 directions in 5° steps starting from 0° to 40° and then in 10° steps from 40° to 90°. The full spherical measurements followed at an a = 0.97 m radius with the mouth aperture at the spherical center. The sampling density and distribution followed the AES 5° dual-equiangular sampling standard, omitting the south pole (θ = 180°). Thus, each spherical directivity assessment included 36 polar-angle θ samples and 72 azimuthal-angle ϕ samples. The presented data include 22 1/3-octave bands, ranging from 80 Hz …

Material Characterization Using Nuclear Magnetic Resonance, Giovanna Marcella Pope

Theses and Dissertations

Nuclear magnetic resonance techniques can provide highly accurate information about the local environment of both liquid and solid samples. In the first half of this dissertation research, solid state NMR has provided experimental evidence for turbostratic disorder in layered covalent organic solids. Additionally, comparison with candidate structures allowed a proposed correction to the accepted structure of Covalent Organic Framework-5. The second half of the dissertation work emphasized liquid NMR spectroscopy applied to doped iron oxides (IOs). In particular, the effect of IOs on water proton T2 relaxation times were determined as a measure of contrast agent efficacy. Both types of …