Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Brigham Young University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 241 - 270 of 2906

Full-Text Articles in Physical Sciences and Mathematics

Statistical Properties Of 2d Navier-Stokes Equations Driven By Quasi-Periodic Force And Degenerate Noise, Rongchang Liu Apr 2022

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 Apr 2022

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 Apr 2022

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 Apr 2022

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 Apr 2022

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 Apr 2022

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 Apr 2022

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 Apr 2022

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 …


Datadescription-Detection Of Sulfur Dioxide By Broadband Cavity-Enhanced Absorption Spectroscopy (Bbceas), Ryan Thalman, Nitish Bhardwaj, Callum Flowerday, Jaron C. Hansen Apr 2022

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 …


Enhancing The Opportunities For Adults With Autism To Find Jobs Using A Job-Matching Algorithm, Joseph T. Bills Apr 2022

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 …


Identification Of Sources Of Air Pollution Using Novel Analytical Techniques And Instruments, Nitish Bhardwaj Mar 2022

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 Mar 2022

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 Mar 2022

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 Mar 2022

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 Mar 2022

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 Mar 2022

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 Feb 2022

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 …


Outvoice: Bringing Transparency To Healthcare, Autumn Clark Feb 2022

Outvoice: Bringing Transparency To Healthcare, Autumn Clark

Undergraduate Honors Theses

Industries are not incentivized to price reasonably and spend responsibly if consumers do not have the ability to shop around within that industry, and shopping around is not possible without pricing transparency (knowing how much a good or service costs before purchasing it). But in the healthcare industry, we typically default to whichever clinic or hospital is closest, with no prior knowledge of what costs we can expect to incur at that particular institution. According to a poll published by Harvard University, nine out of ten Americans feel the healthcare industry is too opaque and greater transparency is needed.

We …


Temperature Relaxation And Magnetically Suppressed Expansion In Strongly Coupled Ultracold Neutral Plasmas, Robert Tucker Sprenkle Dec 2021

Temperature Relaxation And Magnetically Suppressed Expansion In Strongly Coupled Ultracold Neutral Plasmas, Robert Tucker Sprenkle

Theses and Dissertations

Ultracold neutral plasmas provide a platform for studying transport properties in an idealized environment. In this dissertation, transport properties in a Ca$^+$/Yb$^+$ dual species ultracold neutral plasma and a Ca$^+$ magnetized ultracold neutral plasma are studied. In dual species plasmas, we study ion-ion temperature relaxation. We compare measured relaxation rates with atomistic simulations and a range of popular theories. Our work validates the assumptions and capabilities of molecular dynamic simulations and invalidates theoretical models in this regime. This work illustrates an approach for precision determinations of detailed material properties in Coulomb mixtures across a wide range of conditions. We also …


Bayesian, Frequentist, And Information Geometry Approaches To Parametric Uncertainty Quantification Of Classical Empirical Interatomic Potentials, Yonatan Kurniawan Dec 2021

Bayesian, Frequentist, And Information Geometry Approaches To Parametric Uncertainty Quantification Of Classical Empirical Interatomic Potentials, Yonatan Kurniawan

Theses and Dissertations

Uncertainty quantification (UQ) is an increasingly important part of materials modeling. In this paper, we consider the problem of quantifying parametric uncertainty in classical empirical interatomic potentials (IPs). Previous work based on local sensitivity analysis using the Fisher Information has shown that IPs are sloppy, i.e., are insensitive to coordinated changes of many parameter combinations. We confirm these results and further explore the non-local statistics in the context of sloppy model analysis using both Bayesian (MCMC) and Frequentist (profile likelihood) methods. We interface these tools with the Knowledgebase of Interatomic Models (OpenKIM) and study three models based on the Lennard-Jones, …


Development And Characterization Of An Underwater Acoustics Laboratory Via In Situ Impedance Boundary Measurements, Cameron Taylor Vongsawad Dec 2021

Development And Characterization Of An Underwater Acoustics Laboratory Via In Situ Impedance Boundary Measurements, Cameron Taylor Vongsawad

Theses and Dissertations

Modeling underwater acoustic propagation comes with a variety of challenges due to the need for proper characterization of the environmental conditions. These conditions include ever changing and complex water properties as well as boundary conditions. The BYU underwater acoustics open-air tank test-bed and measurement chain were developed to study underwater acoustic propagation within a controlled environment. It was also developed to provide ways to test and validate ocean models without the high cost associated with obtaining open ocean measurements. However, tank measurements require additional characterization of boundary conditions associated with the walls of the tank which would not be present …


An Analysis Of Two Photometric Redshift Methods And Their Uses For Finding Void Galaxies, Rochelle J. Steele Dec 2021

An Analysis Of Two Photometric Redshift Methods And Their Uses For Finding Void Galaxies, Rochelle J. Steele

Theses and Dissertations

An extensive survey of extragalactic objects with accurate distances is difficult to perform. Distance at that scale is commonly found with redshift and most easily identified with spectroscopic observations, which are time intensive. This is especially a concern when surveying for the elusive, possibly non-existent dwarf galaxies in the centers of voids, whose light would be so faint that a spectroscopic survey to find them would be unreasonably time consuming. Photometric methods to calculate redshift could provide a much quicker way to find distance, but the photometric methods used thus far are characterized by large errors that make them unusable …


Pentagonal Extensions Of The Rationals Ramified At A Single Prime, Pablo Miguel Rodriguez Dec 2021

Pentagonal Extensions Of The Rationals Ramified At A Single Prime, Pablo Miguel Rodriguez

Theses and Dissertations

In this thesis, we define a certain group of order 160, which we call a hyperpentagonal group, and we prove that every totally real D5-extension of the rationals ramified at only one prime is contained in a hyperpentagonal extension of the rationals. This generalizes a result of Doud and Childers (originally conjectured by Wong) that every totally real S3 extension of the rationals ramified at only one prime is contained in an S4 extension.


Using Facies Analysis And Reservoir Characterization Of The Albian-Cenomanian Nanushuk Formation To Assist In Better Understanding Interactions Between Shoreface, Deltaic, And Fluvial Systems On The North Slope, Alaska, Andrea Smoot Dec 2021

Using Facies Analysis And Reservoir Characterization Of The Albian-Cenomanian Nanushuk Formation To Assist In Better Understanding Interactions Between Shoreface, Deltaic, And Fluvial Systems On The North Slope, Alaska, Andrea Smoot

Theses and Dissertations

The Albian-Cenomanian Nanushuk Formation located on the North Slope of Alaska is the result of fluvial, deltaic, and shoreface processes and has been the focus of recent petroleum exploration activity in the Colville Basin. The Nanushuk and underlying Torok formations together contain an estimated 8.7 billion barrels of oil and 25 trillion cubic feet of natural gas reserves within the resource-rich North Slope. The Nanushuk Formation is composed of sediment sourced from the Chukotka Peninsula to the west and deposited axially within the Colville Basin. High sedimentation rates led to rapid progradation of shoreface and deltaic systems, which effectively filled …


Deep Parameter Selection For Classic Computer Vision Applications, Michael Whitney Dec 2021

Deep Parameter Selection For Classic Computer Vision Applications, Michael Whitney

Theses and Dissertations

A trend in computer vision today is to retire older, so-called "classic'' methods in favor of ones based on deep neural networks. This has led to tremendous improvements in many areas, but for some problems deep neural solutions may not yet exist or be of practical application. For this and other reasons, classic methods are still widely used in a variety of applications. This paper explores the possibility of using deep neural networks to improve these older methods instead of replace them. In particular, it addresses the issue of parameter selection in these algorithms by using a neural network to …


Minimizer Of A Free Boundary Problem, Mingyan Zhao Dec 2021

Minimizer Of A Free Boundary Problem, Mingyan Zhao

Theses and Dissertations

We study a free boundary problem with initial data given on three-dimensional cones. In particular, we study when the free boundary is allowed to pass through the vertex of the cone, which depends on the cone’s slope, determined by a parameter c. With a mix of analytical and computational methods, we show that the free boundary may pass through the vertex of the cone when c ≤ 0.43.


Modeling A Human Family Network, Rebecca Jo Flores Dec 2021

Modeling A Human Family Network, Rebecca Jo Flores

Theses and Dissertations

We propose a model that generates a family network based on real-world family network data. We use this model to study the extent to which distances to union and the number of children characterize family networks. To determine how accurate our model is we use persistent homology to identify and compare the structure of our modeled family networks to real-world family networks. To accomplish this, we introduce the notion of a network's persistence curve, which encodes the network's set of persistence intervals. Using the bottleneck distance allows us to measure the difference in the homological structure between any pair of …


Quantitative Stem: A Method For Measuring Temperature And Thickness Effects On Thermal Diffuse Scattering Using Stem/Eels, And For Testing Electron Scattering Models, Paul S. Minson Dec 2021

Quantitative Stem: A Method For Measuring Temperature And Thickness Effects On Thermal Diffuse Scattering Using Stem/Eels, And For Testing Electron Scattering Models, Paul S. Minson

Theses and Dissertations

In the last two decades, advances in the dark field detectors and microscopes of scanning transmission electron microscopy (STEM) have inspired a resurgence of interest in quantitative STEM analysis. One promising avenue is the use of STEM as a nanothermometric probe. In this application, thermal diffuse scattering, captured by a CCD camera or an annular dark field detector, acts as an indirect measurement of the specimen temperature. One challenge with taking such a measurement is achieving adequate sensitivity to quantify a change in scattered electron signal on the order of 1% or less of the full electron beam. Another difficulty …


Microwave-Promoted Iminyl Radical Fragmentations And The Total Synthesis Of Yaku'amide A And Its Simplified Analogues, Concordia Lo Dec 2021

Microwave-Promoted Iminyl Radical Fragmentations And The Total Synthesis Of Yaku'amide A And Its Simplified Analogues, Concordia Lo

Theses and Dissertations

The first project in this dissertation describes the use of microwave-promoted iminyl radical fragmentations to form functionalized nitriles. Nitrogen-centered radical chemistry is a useful tool to construct valuable C-N bonds commonly found in pharmaceuticals and biologically active molecules. Classically, these reactions require the use of toxic initiators and propagators. Iminyl radical chemistry has been gaining momentum as a means of avoiding these harsh conditions. This project utilizes the fragmentation of cyclic iminyl radicals via irradiation of O-phenyl oxime ethers to produce a synthetically useful nitrile tethered to an alkyl radical in the absence of metal catalysts and redox chemistry. The …


Electrocatalytic Oxidation Of Carbohydrates Via Surface Immobilized Viologen, Dallin D.V. Scott Dec 2021

Electrocatalytic Oxidation Of Carbohydrates Via Surface Immobilized Viologen, Dallin D.V. Scott

Theses and Dissertations

Earths most abundant biomolecules, carbohydrates, offer tremendous potential forelectricity production. Carbohydrate fuel cells are electrical fuel cells that can harvest the stored electrons in carbohydrates and offer a cheap and efficient method that could help solve growing energy demands, while providing a renewable green energy source. Viologen-mediated carbohydrate fuel cells have demonstrated the ability to accelerate carbohydrate oxidation while decreasing partial or incomplete oxidation products reducing the electricity production. Subsequent studies suggested polymeric viologen compounds could improve the efficiency by increasing the local concentration of viologen. This thesis presents the utility of surface-immobilized viologen mediators for the oxidation of simple …