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

Digital Commons Network™

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

Brigham Young University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1111 - 1140 of 8047

Full-Text Articles in Entire DC Network

Rapid Computation Of Effective Conductivity Of 2d Composites By Equivalent Circuit And Spectral Methods., Ben J. Ransom, Dean R. Wheeler Aug 2021

Rapid Computation Of Effective Conductivity Of 2d Composites By Equivalent Circuit And Spectral Methods., Ben J. Ransom, Dean R. Wheeler

Faculty Publications

This work presents models for homogenizing or finding the effective transport or mechanical properties of microscale composites formed from highly contrasting phases described on a grid. The methods developed here are intended for engineering applications where speed and geometrical flexibility are a premium. A canonical case that is mathematically challenging and yet can be applied to many realistic materials is a 4-phase 2-dimensional periodic checkerboard or tiling. While analytic solutions for calculating effective properties exist for some cases, versatile methods are needed to handle anisotropic and non-square grids. A reinterpretation and extension of an existing analytic solution that utilizes equivalent …

Go to article

Petal Diagrams And Seifert Surfaces, Jason Robert Gardiner Aug 2021

Petal Diagrams And Seifert Surfaces, Jason Robert Gardiner

Theses and Dissertations

Petal diagrams of knots are projections of knots to the plane such that the diagram has exactly one crossing. Petal diagrams offer a convenient and combinatorial way of representing knots via their associated petal permutation. In this thesis we study the fundamental group and Seifert surfaces of knots in petal form. Using the Seifert-Van Kampen theorem, we give a group presentation of the fundamental group of the knot complement of a knot in petal form. We then discuss Seifert surfaces and use decomposition diagrams to represent the Seifert surfaces of knots in petal form. We finally give an algorithm to …

Go to article

Highly Integrated And Miniaturized 3d Printed Serial Dilution Microfluidic Devices For Dose-Response Assays, Jose Luis Sanchez Noriega Aug 2021

Highly Integrated And Miniaturized 3d Printed Serial Dilution Microfluidic Devices For Dose-Response Assays, Jose Luis Sanchez Noriega

Theses and Dissertations

The ability to generate a range of concentrations of various solutions rapidly and conveniently is an ongoing need in biotechnology. In this thesis we demonstrate how we took advantage of the full process control afforded by our recent custom high resolution 3D printer and resin advances to realize highly integrated and miniaturized microfluidic components for simultaneous on-chip serial dilution for dose-response assays. With judicious selection of mixed layer thicknesses and pixel-by-pixel dose control, we show that the diameter of 3D printed membrane valves can be reduced from 300 µm to 46 µm. We further introduce an entirely new kind of …

Go to article

Synthesis And Biological Evaluation Of Pyrazolo[1,5-A]Pyrimidines And (4-Hydroxy-6-Trifluoromethylpyrimidin-2-Yl) Guanidines, Justin Dave Singleton Aug 2021

Synthesis And Biological Evaluation Of Pyrazolo[1,5-A]Pyrimidines And (4-Hydroxy-6-Trifluoromethylpyrimidin-2-Yl) Guanidines, Justin Dave Singleton

Theses and Dissertations

A microwave reactor was used to synthesize a series of novel 3,6-disubstituted or 3-substituted pyrazolo[1,5-a]pyrimidines in a total of 1 hour reaction time over 3 steps. The products were obtained in good to excellent yields (34-92%, ave = 52%) using a straightforward synthesis starting with the reaction of dimethylformamide-dimethylacetal with commercially available aryl acetonitriles (120C, 20 min). This was followed by treatment with H2NNH2 • HBr (120C, 20 min), and then reacted with either 1,1,3,3-tetramethoxypropane or a 2-aryl-substituted malondialdehydes (120C, 20 min). The resulting product was either collected on a sintered glass funnel or purified via column chromatography. The compounds …

Go to article

Math Modeling Of Complex Networks, Zach Boyd Aug 2021

Math Modeling Of Complex Networks, Zach Boyd

BYU Research Development Office Research Networking Conference

graph theory, machine learning, data science, supply chains, computational social science

Go to article

Heat-Induced Skeletal Muscle Mitochondrial Biogenesis And Vascular Remodeling: A Countermeasure For Human Disuse Atrophy And Aging, Robert D. Hyldahl Aug 2021

Heat-Induced Skeletal Muscle Mitochondrial Biogenesis And Vascular Remodeling: A Countermeasure For Human Disuse Atrophy And Aging, Robert D. Hyldahl

BYU Research Development Office Research Networking Conference

Exercise science, chemistry and biochemistry, nutrition, dietetics and food science

Go to article

Using Generalizability Theory And The Erp Reliability Analysis (Era) Toolbox For Assessing Test-Retest Reliability Of Erp Scores Part 1: Algorithms, Framework, And Implementation, Scott A. Baldwin, Peter E. Clayson, Kalie A. Carbine, Joseph A. Olsen, Michael J. Larson Aug 2021

Using Generalizability Theory And The Erp Reliability Analysis (Era) Toolbox For Assessing Test-Retest Reliability Of Erp Scores Part 1: Algorithms, Framework, And Implementation, Scott A. Baldwin, Peter E. Clayson, Kalie A. Carbine, Joseph A. Olsen, Michael J. Larson

Faculty Publications

The reliability of event-related brain potential (ERP) scores depends on study context and how those scores will be used, and reliability must be routinely evaluated. Many factors can influence ERP score reliability; generalizability (G) theory provides a multifaceted approach to estimating the internal consistency and temporal stability of scores that is well suited for ERPs. G theory's approach possesses a number of advantages over classical test theory that make it ideal for pinpointing sources of error in observed scores. The current primer outlines the G-theory approach to estimating internal consistency (coefficients of equivalence) and test-retest reliability (coefficients of stability). This …

Go to article

Linguistics Of Russian Media During The 2016 Us Election: A Corpus-Based Study, Devon K. Terry Jul 2021

Linguistics Of Russian Media During The 2016 Us Election: A Corpus-Based Study, Devon K. Terry

Theses and Dissertations

The purpose of this study is to perform a linguistic analysis of Russian mass media focused on its coverage of the 2016 US presidential election. It will be a corpus-based study, using a corpus as a foundational source for quantitative and qualitative data. This study will use a collection of keywords from the corpus and analyze their contexts as they pertain to Hillary Clinton and Donald Trump. This study uses corpus linguistic research tools such as sentence tokenization, Key Words in Context (KWIC), sentiment analysis, word embedding visualization, word-vector math, word frequency lists, and collocate analysis as part of the …

Go to article

2-Phosphinoimidazole Derived Monometallic And Bimetallic Catalysts, Erin Martinez Jul 2021

2-Phosphinoimidazole Derived Monometallic And Bimetallic Catalysts, Erin Martinez

Theses and Dissertations

Transition metal catalysis is a necessary branch of organic synthesis. Both monometallic and bimetallic catalysts can reduce reaction times, improve regio- and enantioselectivity, and minimize byproducts. Additionally, bimetallic catalysts can cooperatively activate substrates, which can enable new reactions and mechanistic pathways. The first half of this work will describe the synthesis and catalytic ability of our novel Pd(I) and Pd(II) dimers. Both dimers use a 2-phosphinoimidazole ligand scaffold to bring the metal centers in close proximity. The Pd(II) dimer can catalyze the synthesis of 1,3-disubstituted naphthalene rings from commercially available aryl iodides and methyl ketones with high regioselectivity and yields. …

Go to article

Invariant Lattices Of Several Elliptic K3 Surfaces, Joshua Joseph Fullwood Jul 2021

Invariant Lattices Of Several Elliptic K3 Surfaces, Joshua Joseph Fullwood

Theses and Dissertations

This work is concerned with computing the invariant lattices of purely non-symplectic automorphisms of special elliptic K3 surfaces. Brandhorst gave a collection of K3 surfaces admitting purely non-symplectic automorphisms that are uniquely determined up to isomorphism by certain invariants. For many of these surfaces, the automorphism is also unique or the automorphism group of the surface is finite and with a nice isomorphism class. Understanding the invariant lattices of these automorphisms and surfaces is interesting because of these uniqueness properties and because it is possible to give explicit generators for the Picard and invariant lattices. We use the methods given …

Go to article

An Εhf And Δ18o Isotopic Study Of Zircon Of The Mount Osceola And Conway Granites, White Mountain Batholith, New Hampshire: Deciphering The Petrogenesis Of A-Type Granites, Javier Fabian Matos Strauss Jul 2021

An Εhf And Δ18o Isotopic Study Of Zircon Of The Mount Osceola And Conway Granites, White Mountain Batholith, New Hampshire: Deciphering The Petrogenesis Of A-Type Granites, Javier Fabian Matos Strauss

Theses and Dissertations

A-type granites form in anorogenic settings and typically have high REE concentrations, K2O, Na2O, SiO2, FeOtotal, but low contents of Al2O3, MgO, CaO compared to other granite types. They have been divided in two groups according to their geochemical characteristics: differentiates of mantle-derived magmas (A1), and granites that are the result of melting depleted, lower crust (A2). The two largest A-type granites of the Mesozoic White Mountain Batholith of New Hampshire are the Mount Osceola and Conway granites. Electron microprobe analyses of biotite and amphibole in both granites are similar to those in other A-type granites: Fe-rich, but low MgO, …

Go to article

Relative Infrasound Calibration Of Microphones With Application To Outdoor Vector Intensity Measurements, Francisco Javier Irarrazabal Oliva Jul 2021

Relative Infrasound Calibration Of Microphones With Application To Outdoor Vector Intensity Measurements, Francisco Javier Irarrazabal Oliva

Theses and Dissertations

This thesis describes the phase and amplitude correction of 12.7 mm diameter, Type-1 microphones for three frequency bands, including within the infrasound regime, and its application to acoustic measurements. Previous data stem from acoustic intensity measurements using two-dimensional, four-microphone probes, which emphasized the requirement of having the acoustic phase and amplitude difference be much greater than the interchannel mismatch. Although correcting the amplitude/phase is well-known, obtaining the necessary transfer functions in the infrasound regime is challenging because (1) signal-to-noise ratios are often poor, (2) long measurement times are required for averaging, and (3) microphone responses vary significantly across these low …

Go to article

Increasing Introductory Biology Students' Modeling Mastery Through Visualizing Population Growth Models, Samantha Rae Wasson Jul 2021

Increasing Introductory Biology Students' Modeling Mastery Through Visualizing Population Growth Models, Samantha Rae Wasson

Theses and Dissertations

In introductory biology, college students are taught to predict how populations will grow and change over time by using population growth models. These models are commonly represented as mathematical equations. However, students consistently struggle when math and biology concepts intersect in the classroom, and these struggles lead to suboptimal understanding of how mathematical population models are designed and used. Education literature suggests that students may struggle with population modeling because of math anxiety, the high cognitive load of the task, and the lack of scaffolding for abstract concepts. In our study, we sought to improve student mastery modeling exponential growth, …

Go to article

Synthesis And Utility Of Chiral And Achiral Trifluoroacetamide Substrates In Cycloaddition Reactions, Isaac Theodore Smith Jul 2021

Synthesis And Utility Of Chiral And Achiral Trifluoroacetamide Substrates In Cycloaddition Reactions, Isaac Theodore Smith

Theses and Dissertations

In this document we report the synthesis, characterization, and utility of a chiral amidoacrylate substrate. This substrate features a reactive alkene that can be used in a variety of reactions. [3+2]-Cycloaddition reactions to form pyrroloindolines are shown to proceed with excellent diastereoselectivity (>20:1) and yield (86%). [3+2]-Reactions allow for the stereoselective construction of the pyrroloindoline backbone common in many natural products. Diels-Alder reactions catalyzed by TiCl4 show high yields (82%) with ~2:1 diastereoselectivity. Cyclopropanation reactions proceed in moderate yield (71%) and diastereoselectivity (~3:1). Both Diels-Alder and cyclopropanation reactions utilizing the chiral amidoacrylate substrate serve to stereoselectively produce unnatural amino …

Go to article

The Music Of Rivers: How Climate, Land Use, And Disturbances Tune The Frequencies And Volumes Of Streams Worldwide, Brian Charles Brown Jul 2021

The Music Of Rivers: How Climate, Land Use, And Disturbances Tune The Frequencies And Volumes Of Streams Worldwide, Brian Charles Brown

Theses and Dissertations

The amount of water flowing through streams and rivers changes through time. The seasonality and duration of these changes can have profound impacts on human freshwater availability, aquatic habitat, and biogeochemical cycling. Numerous factors are thought to influence streamflow regime, including drainage basin area, temperature, precipitation, and land cover. Few of these qualities have remained untouched, either directly or indirectly, by expanding human activities. Altered climate, sweeping changes to large portions of the earth's surface, and the construction of dams and other infrastructure have fundamentally altered streamflows worldwide. Understanding the nature of these changes, both globally and regionally in the …

Go to article

Protein Conformational Stability Enhancement Through Pegylation And Macrocyclization, Qiang Xiao Jul 2021

Protein Conformational Stability Enhancement Through Pegylation And Macrocyclization, Qiang Xiao

Theses and Dissertations

PEGylation can improve the pharmacokinetic properties of protein therapeutics via decreasing renal clearance and shielding the protein surface from proteases, antibody neutrailization, and aggregation. Conformational stability enhancement can provide criteria for the identification of optimal sites for PEGylation, but how PEG influence the noncovalent interactions from the surface of proteins has not been well illustrated. Macrocyclization can effectively enhance the conformational stability of small peptides and large proteins. Combination of PEG-based conformational stability enhancement and macrocyclization-based conformational constraint has not been explored. Macrocycliziation has been employed to stabilize protein tertiary structures, but there are no general guidelines for interhelical staple …

Go to article

Exploration Of Constant-Force Wristbands For A Wearable Health Device, Thomas Alexander Naylor Jul 2021

Exploration Of Constant-Force Wristbands For A Wearable Health Device, Thomas Alexander Naylor

Theses and Dissertations

Wearable Health Devices (WHDs) are an emerging technology that enables continuous monitoring of vital signs during daily life. Issues with constant and consistent data acquisition have been found while WHD technology has developed. The force of the measurement area and movement of the sensors are key mechanical issues that need to be solved for WHDs to become a viable way to continuously monitor health conditions. This work explores Constant-Force Mechanisms (CFMs) as a solution to problems the current WHD industry faces. Additionally, the relationship between force provided from the mechanism, sensor pressure on the wrist, patient comfort, and sensor readings …

Go to article

Nonlinear Ultrafast Excitation And Two-Dimensional Terahertz Spectroscopy Of Solids, Brittany E. Knighton Jul 2021

Nonlinear Ultrafast Excitation And Two-Dimensional Terahertz Spectroscopy Of Solids, Brittany E. Knighton

Theses and Dissertations

Ultrafast spectroscopy allows us to probe and understand material properties. With it, we can measure phonon-polaritons (optical phonons coupled with light) and the resulting dispersion curve in lithium niobate. Customizing the excitation source in ultrafast measurements can excite phonon modes to large amplitudes, allowing the experimental exploration of the Potential Energy Surface in solids. However, stronger pump fluences and bigger signal isn't always the answer in ultrafast spectroscopy. When sample signals and their nonlinear and mechanisms cannot be distinguished with 1D measurements, simple 2D THz measurements are a great place to start searching for distinct factors as was the case …

Go to article

Plot Extraction And The Visualization Of Narrative Flow, Michael A. Debuse Jul 2021

Plot Extraction And The Visualization Of Narrative Flow, Michael A. Debuse

Theses and Dissertations

In order to facilitate the automated extraction of complex features and structures within narrative, namely plot in this study, two proof-of-concept methods of narrative visualization are presented with the goal of representing the plot of the narrative. Plot is defined to give a basis for quality assessment and comparison. The first visualization presented is a scatter-plot of entities within the story, but due to failing to uphold the definition of plot, in-depth analysis is not performed. The second visualization presented is a graph structure that better represents a mapping of the plot of the story. Narrative structures commonly found within …

Go to article

3-Adic Properties Of Hecke Traces Of Singular Moduli, Miriam Beazer Jul 2021

3-Adic Properties Of Hecke Traces Of Singular Moduli, Miriam Beazer

Theses and Dissertations

As shown by Zagier, singular moduli can be represented by the coefficients of a certain half integer weight modular form. Congruences for singular moduli modulo arbitrary primes have been proved by Ahlgren and Ono, Edixhoven, and Jenkins. Computation suggests that stronger congruences hold for small primes $p \in \{2, 3, 5, 7, 11\}$. Boylan proved stronger congruences hold in the case where $p=2$. We conjecture congruences for singular moduli modulo powers of $p \in \{3, 5, 7, 11\}$. In particular, we study the case where $p=3$ and reduce the conjecture to a congruence for a simpler modular form.

Go to article

The Non-Backtracking Spectrum Of A Graph And Non-Bactracking Pagerank, Cory Glover Jul 2021

The Non-Backtracking Spectrum Of A Graph And Non-Bactracking Pagerank, Cory Glover

Theses and Dissertations

This thesis studies two problems centered around non-backtracking walks on graphs. First, we analyze the spectrum of the non-backtracking matrix of a graph. We show how to obtain the eigenvectors of the non-backtracking matrix using a smaller matrix and in doing so, create a block diagonal decomposition which more clearly expresses the non-backtracking matrix eigenvalues. Additionally, we develop upper and lower bounds on the matrix spectrum and use the spectrum to investigate properties of the graph. Second, we investigate the difference between PageRank and non-backtracking PageRank. We show some instances where there is no difference and develop an algorithm to …

Go to article

Emotional Geographies Of Beginning And Veteran Reformed Teachers In Mentor/Mentee Relationships, Emily Joan Adams Jul 2021

Emotional Geographies Of Beginning And Veteran Reformed Teachers In Mentor/Mentee Relationships, Emily Joan Adams

Theses and Dissertations

Reformed teaching is better for students' conceptual understanding compared to the more popular traditional style of teaching. Many beginning teachers wanting to teach reformed conform to traditional teaching within their first couple years of teaching. I argue that this can happen because the emotional labor to continue teaching reformed without support is too high. Having a reformed math mentor can decrease this emotional labor and provide more support to beginning reformed teachers. This study builds on and adds to Hargreaves (2001) emotional geography framework to better understand the emotional closeness/distance beginning and veteran reformed teachers have talking about their practice. …

Go to article

Precision Maritime Landing Of Autonomous Multirotor Aircraft With Real-Time Kinematic Gnss, Matthew Kent Rydalch Jul 2021

Precision Maritime Landing Of Autonomous Multirotor Aircraft With Real-Time Kinematic Gnss, Matthew Kent Rydalch

Theses and Dissertations

In this thesis two methods were developed for precise maritime landing of an autonomous multirotor aircraft based on real-time kinematic (RTK) Global Navigation Satellite System (GNSS). The first method called RTK-localized method (RLM) uses RTK GNSS measurements to localize a sea vessel and execute the landing. RLM was demonstrated outdoors in hardware and landed on a physically simulated boat called a mock-boat with an average landing error of 9.7 cm. The mock-boat was actuated to have boat-like motion and a forward velocity of ~2 m/s. This method showed that accurate landing is possible with RTK GNSS as the primary means …

Go to article

Tp-5801 In Vitro Kinase Screen Data, Joshua Andersen Jul 2021

Tp-5801 In Vitro Kinase Screen Data, Joshua Andersen

ScholarsArchive Data

In vitro kinase screen data for TP-5801 to accompany Chan and Egbert et al., Nature Communications, 2021 (in press)

Go to article

Each Atom An Agent?, Steven L. Peck Jul 2021

Each Atom An Agent?, Steven L. Peck

BYU Studies

An agent, broadly conceived, references something causally efficacious. More narrowly, the word agent is usually deployed in at least three senses. The first is as brute causality. For example, to say that water is an agent of erosion on vegetatively barren hillsides is to claim that water directly causes the removal of the soil in particular drainage systems. The second sense, used predominately in biology, recognizes an agent as an individual autonomous system that constrains the flow of energy and matter such that its actions are performed for particular functions or goals. For instance, a simple bacterium is drawn to …

Go to article

Influencing Perceptions Of Stem Through The Best Stem Books List, Scott Bartholomew, Alexia Seymour Jul 2021

Influencing Perceptions Of Stem Through The Best Stem Books List, Scott Bartholomew, Alexia Seymour

Faculty Publications

One day, while discussing engineering and science as potential career options with a female student, we opened a search engine and typed in “engineer” and “scientist.” However, on the first pages of image results, only one female appeared for engineering and only a few females appeared for “scientist” (see Figure 1). This disparity was disturbing—if this student never saw another person like her filling careers in STEM fields, would she ever “picture herself” in those fields?

Go to article

Sequence Specific Concentration And Labeling Of Bacterial Plasmids For Future Use In Detection Of Drug-Resistant Sepsis Cases Without Amplification, Robert L. Hanson Jun 2021

Sequence Specific Concentration And Labeling Of Bacterial Plasmids For Future Use In Detection Of Drug-Resistant Sepsis Cases Without Amplification, Robert L. Hanson

Theses and Dissertations

Rapidly diagnosing the precise drug resistance present in sepsis-inducing bacteria is a continuing need to maintain the efficacy of our medical systems. Diagnostics currently being developed for such scenarios are either sensitive or rapid, but not both. Sequence-specific single DNA molecule analysis could fill this gap if it could be adapted to work on smaller targets, similar to those produced by classical biological methods. In this work, I demonstrate that immobilized ssDNA in the appropriate hybridization buffer can rapidly pull its complementary sequence out of solution. I also demonstrate that such systems in a microfluidic chip can be used to …

Go to article

Localized Anthropogenic And Geogenic Groundwater Contamination In The Structurally Complex Carbonate-Hosted East Tintic Mining District, Eureka, Ut, Usa, Cameron Patrick Cordner Jun 2021

Localized Anthropogenic And Geogenic Groundwater Contamination In The Structurally Complex Carbonate-Hosted East Tintic Mining District, Eureka, Ut, Usa, Cameron Patrick Cordner

Theses and Dissertations

Legacy mining areas throughout the world contain widespread contaminated surface and groundwater from both anthropogenic and geogenic sources. Abandoned mine waste can contribute harmful solutes to groundwater and surface water, as metals mobilize through oxidation of sulfide minerals. Geogenic contaminant sources, such as geothermal water and mineralization, may also contribute to groundwater pollution in mining areas. To investigate the relationship between various groundwater contamination sources in legacy mining areas we sampled ~30 cold springs in the East Tintic Mountains of Utah and 8 regional hot springs as a proxy for geothermal water during fall 2019 and spring/summer 2020. Water chemistry …

Go to article

Bottom-Up Fabrication And Characterization Of Dna Origami-Templated Electronic Nanomaterials, Basu Ram Aryal Jun 2021

Bottom-Up Fabrication And Characterization Of Dna Origami-Templated Electronic Nanomaterials, Basu Ram Aryal

Theses and Dissertations

This work presents the bottom-up fabrication of DNA origami-assembled metal nanowires and metal-semiconductor junctions, and their electrical characterization. Integration of metal and semiconductor nanomaterials into prescribed sites on self-assembled DNA origami has facilitated the fabrication of electronic nanomaterials, whereas use of conventional tools in their characterization combines bottom-up and top-down technologies. To expand the contemporary DNA-based nanofabrication into nanoelectronics, I performed site-specific metallization of DNA origami to create arbitrarily arranged gold nanostructures. I reported improved yields and conductivity measurements for Au nanowires created on DNA origami tile substrates. I measured the conductivity of C-shaped Au nanowires created on DNA tiles …

Go to article

Girls In Stem, Elizabeth Wood Jun 2021

Girls In Stem, Elizabeth Wood

Marriott Student Review

There is a huge disparity in gender gap in STEM fields. Research has shown that companies work better and innovation thrives when the workforce is more diverse. However, many girls face untrue stereotypes and cultural pressure that they should not pursue STEM careers. It is up to us to change the negative perceptions of girls working in STEM and instead support and uplift girls and encourage them to work in STEM. Girls have the power to change the world for the better and everyone needs to help and encourage them to do it!

Go to article

First Prev Next Last