Physical Sciences and Mathematics Commons^™

The Design And Testing Of Fluorescence-Based Sensors For Phosphate And Phosphonate, Sara Hassanzadehroknabadi

Electronic Theses and Dissertations

Inorganic phosphate (Pi) is an essential compound for all living things, as it serves as a component of nucleic acids and ATP, which are required for plant growth and proliferation. However, when excess Pi enters the aquatic environment, it has severe detrimental effects through the induction of harmful algal blooms (HAB), which negatively impact aquatic life, the quality of drinking water as well as recreational activities. It is therefore critical to have fast, sensitive, and inexpensive sensors for Pi that quickly and quantitively measure its concentration in a field setting.

Phosphonates or organophosphorus compounds are phosphoric acids possessing alkyl or …

Classification Of Electropherograms Using Machine Learning For Parkinson’S Disease, Soroush Dehghan

Electronic Theses and Dissertations

Parkinson’s disease (PD) is a neurodegenerative movement disorder that progresses gradually over time. The onset of symptoms in people who are suffering from PD can vary from case to case, and it depends on the progression of the disease in each patient. The PD symptoms gradually develop and exacerbate the patient’s movements throughout time. An early diagnosis of PD could improve the outcomes of treatments and could potentially delay the progression of this disorder and that makes discovering a new diagnostic method valuable. In this study, I investigate the feasibility of using a machine learning (ML) approach to classify PD …

Multi-Agent Pathfinding In Mixed Discrete-Continuous Time And Space, Thayne T. Walker

Electronic Theses and Dissertations

In the multi-agent pathfinding (MAPF) problem, agents must move from their current locations to their individual destinations while avoiding collisions. Ideally, agents move to their destinations as quickly and efficiently as possible. MAPF has many real-world applications such as navigation, warehouse automation, package delivery and games. Coordination of agents is necessary in order to avoid conflicts, however, it can be very computationally expensive to find mutually conflict-free paths for multiple agents – especially as the number of agents is increased. Existing state-ofthe- art algorithms have been focused on simplified problems on grids where agents have no shape or volume, and …

Digital Searching: A Grounded Theory Study On The Modern Search Experience, Nicolas Armando Parés

Electronic Theses and Dissertations

This Grounded theory study explores US adults' modern information search process as they pursue information through digital search user interfaces and tools. To study the current search process, a systematic grounded theory methodology and two data collection methods, a think-aloud protocol and semi-structured interviews, are used to develop the theory. The emerging theory addressed two tightly connected research questions that asked, “What is the process by which humans search and discover information?” and “What is the process by which search and discovery interfaces and tools support the modern search process?”

The study collects participant data from US adults who have …

The Synthesis And Biocatalytic Reduction Of Beta-Keto Alkynes, Rhema M. Francis

Electronic Theses and Dissertations

The preparation of enantiopure homopropargyl alcohols (but-3-yn-ols) is of high importance to the scientific community. They are employed as valuable pharmaceutical intermediates and are opportune to generate antiviral nucleoside analogues. Chiral inducement of these molecules thus far has been poor (low ee) and has constituted a key challenge for asymmetric synthesis in the last few decades. Enzyme-catalyzed enantioselective reductions of ketones have become popular to produce thus-prepared synthons on an industrial scale. Among them, biocatalysts (dehydrogenases, reductases) emerge as a biodegradable option for chemical transformations, in comparison to chiral catalysts that employ highly toxic metals. This research investigates the catalytic …

The Application Of Deep Learning And Cloud Technologies To Data Science, Ian A. Trawinski

Electronic Theses and Dissertations

Machine Learning and Cloud Computing have become a staple to businesses and educational institutions over the recent years. The two forefronts of big data solutions have garnered technology giants to race for the superior implementation of both Machine Learning and Cloud Computing. The objective of this thesis is to test and utilize AWS SageMaker in three different applications: time-series forecasting with sentiment analysis, automated Machine Learning (AutoML), and finally anomaly detection. The first study covered is a sentiment-based LSTM for stock price prediction. The LSTM was created with two methods, the first being SQL Server Data Tools, and the second …

Soil Resilience And Arbuscular Mycorrhizal Fungi: How Fungi Can Inform Climate Change Mitigation And Adaptation In Maya Milpa Management, Courtney Mathers

Electronic Theses and Dissertations

In Mexico’s state of Yucatán, climate change impacts like prolonged and less predictable dry season length are manifesting as threats to agricultural production and food security. Nearly two thirds of Yucatán’s population is indigenous, many of whom live in rural communities that rely on rainfed subsistence agriculture (INEGI 2015). Ensuring sufficient food production in the face of climate change relies on the quality of agricultural soils. With both mismanagement of agricultural soils and climate change posing as threats to food production in Mexico, soil management practices that increase a soil quality should be identified and promoted. The primary objective of …

Electron Spin Relaxation Of Nitroxide Spin Labels And Relaxation Processes, Thacien Ngendahimana

Electronic Theses and Dissertations

MTSL is the nitroxide spin label that is most commonly used in site-directed spin labeling. However, due to rotation of its gem-dimethyl groups that average anisotropic interactions, T_m becomes short above about 70 K and this makes DEER experiments difficult at these temperatures. Strategies for decreasing spin echo dephasing and electron spin lattice relaxation rates are important for design of nitroxide spin labels and molecular qubits.

In searching for labels with longer T_m, new nitroxide spin labels devoid of gemdimethyl groups or with more rigid structures were synthesized at the University of Nebraska and pulsed EPR measurements …

Local-Global Results On Discrete Structures, Alexander Lewis Stevens

Electronic Theses and Dissertations

Local-global arguments, or those which glean global insights from local information, are central ideas in many areas of mathematics and computer science. For instance, in computer science a greedy algorithm makes locally optimal choices that are guaranteed to be consistent with a globally optimal solution. On the mathematical end, global information on Riemannian manifolds is often implied by (local) curvature lower bounds. Discrete notions of graph curvature have recently emerged, allowing ideas pioneered in Riemannian geometry to be extended to the discrete setting. Bakry- Émery curvature has been one such successful notion of curvature. In this thesis we use combinatorial …

Could Alexa Increase Your Social Worth?, Peter Tripp

Electronic Theses and Dissertations

People have historically used personal introductions to build social capital, which is the foundation of career networking and is perhaps the most effective way to advance a career (Lin, 2001). With societal changes, such as the pandemic (Venkatesh & Edirappuli, 2020), and the increasing capabilities of Artificial Intelligence (AI), new approaches may emerge that impact societal relationships. Social capital theory highlights the need for reciprocal agreements to establish the trust between parties (Gouldner, 1960). My theoretical prediction and focus of this research include two principles: The impact of reciprocity in evaluating trust of the source of the introduction and the …

Mis-Specification Of Functional Forms In Growth Mixture Modeling: A Monte Carlo Simulation, Richa Ghevarghese

Electronic Theses and Dissertations

Growth mixture modeling (GMM) is a methodological tool used to represent heterogeneity in longitudinal datasets through the identification of unobserved subgroups following qualitatively and quantitatively distinct trajectories in a population. These growth trajectories or functional forms are informed by the underlying developmental theory, are distinct to each subgroup, and form the core assumptions of the model. Therefore, the accuracy of the assumed functional forms of growth strongly influences substantive research and theories of growth. While there is evidence of mis-specified functional forms of growth in GMM literature, the weight of this violation has been largely overlooked. Current solutions to circumvent …

Using The Fraction Of Missing Information (Fmi) In Selecting Auxiliary Variables To Impute Missingness In Confirmatory Factor Analysis (Cfa), Dareen Taha Alzahrani

Electronic Theses and Dissertations

This study aimed to investigate the effectiveness of using the fraction of missing information (FMI) to select auxiliary variables in imputing missing data in confirmatory factor analysis (CFA). This was done by conducting two studies (a simulation study and an empirical study). A Monte Carlo simulation technique was used to compare the performance and the effect of the restrictive strategy based on FMI and the inclusive strategy on parameter estimate bias and parameter estimate efficiency. The missing data mechanisms, missing data proportion, correlation strength between the analysis variables and auxiliary variables, and the inclusive and restrictive strategies were assessed in …

Bicycles And Transit: Weather Or Not: A Study On The Effect Of Weather And Air Quality On Bicycle-Transit, Bicycle, Rail Transit Counts In Denver, Christiana M. Fairfield

Electronic Theses and Dissertations

The movement of people and goods within metropolitan areas is critically important to the operational efficiency and functionality of cities. This study explores the influence of local weather conditions and the air quality index on bicycle-transit user in Denver, Colorado. Based on bicycle-transit having two key components, bicycle and transit, the effect of local weather conditions and the air quality index is also explored with bicycle use and rail-transit usage. Key findings include: (1) the most significant variable across all three modes is temperature, (2) for bicycle-transit and bicycle use, there is a steady increase in ridership as temperatures increase …

On Loop Commutators, Quaternionic Automorphic Loops, And Related Topics, Mariah Kathleen Barnes

Electronic Theses and Dissertations

This dissertation deals with three topics inside loop and quasigroup theory. First, as a continuation of the project started by David Stanovský and Petr Vojtĕchovský, we study the commutator of congruences defined by Freese and McKenzie in order to create a more pleasing, equivalent definition of the commutator inside of loops. Moreover, we show that the commutator can be characterized by the generators of the inner mapping group of the loop. We then translate these results to characterize the commutator of two normal subloops of any loop.

Second, we study automorphic loops with the desire to find more examples of …

Frequency Analysis Of Trabecular Bone Structure, Daniel Parada San Martin

Electronic Theses and Dissertations

Medical data is hard to obtain due to privacy laws making research difficult. Many databases of medical data have been compiled over the years and are available to the scientific community. These databases are not comprehensive and lack many clinical conditions. Certain type of medical conditions are rare, making them harder to obtain, or are not present at all in the aforementioned databases. Due to the sparsity or complete lack of data regarding certain conditions, research has stifled. Recent developments in machine learning and generative neural networks have made it possible to generate realistic data that can overcome the lack …

Esipt-Enabled Alkyne Migration Provides Rapid Access To Benzoxazinones, Andrés G. Muñoz

Electronic Theses and Dissertations

Benozoxazinones have long been of interest to agrochemical scientists and medicinal chemists because of their widespread biological activity. These scaffolds are also of interest to synthetic chemists, who recognize the utility of benzoxazinones for accessing functionalized heterocycles. The use of efavirenz, a benzoxazinone-based reverse transcriptase inhibitor used in the treatment of HIV-1, has brought increased attention to this privileged pharmacophore. While there exist numerous strategies for synthesizing benzoxazinones, methods that do not require the use of acutely toxic and environmentally hazardous reagents are lacking. Consequently, there is a need to develop new methods for constructing this valuable scaffold. Herein, we …

Ring Bose–Einstein Condensate Atomtronic Rotation Sensor, Oluwatobi I. Adeniji

Electronic Theses and Dissertations

We propose a design for an atomtronic rotation sensor consisting of an array of Bose– Einstein condensates (BECs) confined in a double–target–array potential. The purpose of the sensor is to measure the rotation speed, Ω_R, of the sensor’s rest frame with respect to the “fixed stars.” The atomtronic system consists of an ultracold gas of sodium atoms compressed, using laser light, into a thin horizontal sheet and subjected to a double–target– array potential within the horizontal plane. A “target” BEC consists of a disk–shaped condensate surrounded by a concentric ring–shaped condensate. A “double–target” BEC is two adjacent target …

Synthesis Of Functionalized Aromatic Heterocyclic Compounds And Its Applications In Organized Self-Assemblies, Emmanuel T. Fasusi

Electronic Theses and Dissertations

1,2,3-triazoles due to their structure, possess good optical properties and are capable of molecular recognition by their supramolecular capabilities of utilizing weak forces of interaction (such as hydrogen bonding, dipole interaction) in establishing a close association with targets. They are easy to synthesize, which opened the opportunity for a wide pharmaceutical application, mostly as pharmacological scaffolds. However, challenges such as poor water solubility, inefficient drug delivery and increased toxicities due to frequent dosing of drugs are commonly faced which reduces the efficacy of the drugs. It is therefore important to have “delivery vehicles” which could help transport the drugs to …

Evaluation Of Tidal Fresh Forest Distributions And Tropical Storm Impacts Using Sentinel-2 Msi Imagery, Galen Costomiris

Electronic Theses and Dissertations

Situated in the transitional zone between non-tidal forests upstream and tidal fresh marshes downstream, tidal fresh forests occupy a unique and increasingly precarious habitat. The threat of intensifying anthropogenic climate change, compounded by the effects of historical logging and drainage alterations, could reduce the extent of this valuable ecosystem. The overall goals of this project were to identify forest communities present in the Altamaha tidal fresh forest; develop satellite imagery-based classifications of tidal fresh forest and tidal marsh vegetation along the Altamaha River, Georgia; and to quantify changes in vegetation distribution in the aftermath of hurricanes Matthew and Irma. Based …

Efficient Numerical Optimization For Parallel Dynamic Optimal Power Flow Simulation Using Network Geometry, Rylee Sundermann

Electronic Theses and Dissertations

In this work, we present a parallel method for accelerating the multi-period dynamic optimal power flow (DOPF). Our approach involves a distributed-memory parallelization of DOPF time-steps, use of a newly developed parallel primal-dual interior point method, and an iterative Krylov subspace linear solver with a block-Jacobi preconditioning scheme. The parallel primal-dual interior point method has been implemented and distributed in the open-source PETSc library and is currently available. We present the formulation of the DOPF problem, the developed primal dual interior point method solver, the parallel implementation, and results on various multi-core machines. We demonstrate the effectiveness our proposed block-Jacobi …

Combining Soil Health And Fertility Measurements To Improve The Accuracy Of Predicting Corn Grain Yield Responses To P And K Fertilization, Benjamin Groebner

Electronic Theses and Dissertations

Researchers have pointed to changes in climate and land management practices to justify the need to reevaluate the accuracy of current South Dakota (SD) corn (Zea mays L.) P and K fertilizer recommendations. Also, an increase in soil health understanding has created the potential for soil health measurements to be used to improve the accuracy of these recommendations. The objectives for this study were to 1) evaluate the current P and K critical values and 2) determine the effect of including soil health indicators on improving fertilizer recommendation accuracy. This project was conducted throughout central and eastern SD from 2019-2021 …

Characterization Of A Three-Way Catalyst For High Efficiency Spark Ignition Engines, Cavin Hesketh

Electronic Theses and Dissertations

The push for environmental protection and sustainability has led to strict emission regulations for automotive manufacturers as evident in EURO VII and 2026 EPA requirements set to take effect in the coming years. The modern gasoline spark ignition (SI) engine typically employs various in-cylinder emission reduction techniques along with an exhaust after-treatment system to comply with emission standards. The three-way catalyst (TWC) is wholly responsible for removing the engine-out emissions including hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx). The main objective of this thesis is to investigate the impact of extensive exhaust gas recirculation (EGR) on …

Hardware Implementations Of Spiking Neural Networks And Artificially Intelligent Systems, Alexander J. Leigh

Electronic Theses and Dissertations

Artificial spiking neural networks are gaining increasing prominence due to their potential advantages over traditional, time-static artificial neural networks. Custom hardware implementations of spiking neural networks present many advantages over other implementation mediums. Two main topics are the focus of this work. Firstly, digital hardware implementations of spiking neurons and neuromorphic hardware are explored and presented. These implementations include novel implementations for lowered digital hardware requirements and reduced power consumption.

The second section of this work proposes a novel method for selectively adding sparsity to a spiking neural network based on training set images for pattern recognition applications, thereby greatly …

Studies Of Layered Elastomeric Substrates And Shellac Films For Stretchable And Printed Electronics, Calum Noade

Electronic Theses and Dissertations

Wearable electronics are becoming increasingly common in daily life for a variety of uses. Wearable electronic devices that wish not to be bulky and cumbersome to the user must be stretchable and conformable to the human body. This is a challenge, however, as stretchable polymers are often not as conductive as metal conductors, and metal films applied to elastic substrates are themselves inelastic and will rupture at very low elongations, rendering devices unusable. By using subsurface modification of a multilayered elastomer and brittle layer system, it is possible to offer strain delocalization to a gold film in order to induce …

The Equality Case Of The Kraft And The Kraft-Mcmillan Inequalities, Xavier Nunes

Electronic Theses and Dissertations

In this thesis, we analyze the Kraft Inequality and the Kraft-McMillan Inequality in their equality cases. Kraft’s Inequality deals with prefix-free code and Kraft-McMillan’s Inequality deals with uniquely decodable codes. The focus of the Kraft Inequality analysis is to study the occurrence of prefix-free codes that satisfy the equality case and the structure of words in the code when the equality condition is met. The second part of the thesis touches on the Kraft-McMillan Inequality. Since the proof of this latter inequality uses limits, we cannot immediately analyse its equality cases. The paper will therefore study the equality cases of …

Enhancing Multi-View 3d-Reconstruction Using Multi-Frame Super Resolution, Michael Lee

Electronic Theses and Dissertations

Multi-view stereo is a popular method for 3D-reconstruction. Super resolution is a technique used to produce high resolution output from low resolution input. Since the quality of 3D-reconstruction is directly dependent on the input, a simple path is to improve the resolution of the input.

In this dissertation, we explore the idea of using super resolution to improve 3D-reconstruction at the input stage of the multi-view stereo framework. In particular, we show that multi-view stereo when combined with multi-frame super resolution produces a more accurate 3D-reconstruction.

The proposed method utilizes images with sub-pixel camera movements to produce high resolution output. …

Understanding The Impacts Of Urban Agriculture In Gentrifying Neighborhoods In Denver, Kate Johnson

Electronic Theses and Dissertations

Urban Agriculture is prominent in cities across the United States and has been studied in relation to food security, sustainability, and gentrification. Urban agriculture is context specific and can include individual gardens, community gardens, guerilla gardening, and urban farms. Urban agriculture is a product of the community it is based in, depending on politics, history, and social environments. For these reasons, the relationship between urban agriculture and the community is an area where more research is needed. This thesis explores the role visible gardens play in community building, sustainability, and food security in gentrifying neighborhoods in Denver. Through qualitative methods …

Investigating Spatiotemporal Kinetics, Dynamics, And Mechanism Of Exosome Release, Anarkali Mahmood

Electronic Theses and Dissertations

Exosomes are small lipid-based vesicles that can carry biomolecules from one cell to another. While exosomes are crucial to maintain homeostasis in healthy cells, they are exploited by unhealthy cells to aid disease progression. Exosomes likely facilitate disease progression via the transfer of disease-causing biomolecules from unhealthy to healthy cells. Exosomes are generated in Multivesicular endosomes (MVEs) and are then secreted into the extracellular space to travel to other cells. Despite being a crucial step, very little is known about exosomes release mechanism and dynamics. To further our understanding of exosomes, specifically their secretion, my work has focused on investigating …

Measurements Of Atmospheric Radicals, Heather L. Runberg

Electronic Theses and Dissertations

Atmospheric particulate matter (PM) is a global health concern. PM_2.5 is formed primarily through combustion processes such as automobile use and industrial activity. Natural sources of PM_2.5 result from events like volcanos and wildfires. Upon inhalation, PM_2.5 is small enough to travel deep into the lungs where it can form reactive oxygen species (ROS), such as hydroxyl radical (OH), causing oxidative damage to pulmonary tissues. PM_2.5 has been linked to cardiopulmonary diseases such as asthma, chronic obstructive pulmonary disease (COPD), and high blood pressure.

PM_2.5 is small enough to remain aloft and travel many hundreds …

Machine-Learning And Meta-Analysis Techniques To Quantify And Predict Soil Organic Carbon, N2O-N And Co2-C Emissions In Cover Crop Systems, Deepak Raj Joshi

Electronic Theses and Dissertations

People worldwide are challenged by multiple threats including climate change, growing populations, and soil degradation. Addressing these challenges requires understanding of the local environment, farming systems and modern technologies. These technologies include new ways to process information that include artificial intelligence, machine learning and meta-analysis. Models produced using these technologies may be useful for predicting the consequences of implementing conservation practices that reduce GHG emissions as well as for determining the carbon footprint of cropping systems that include environmentally friendly conservation technologies such as growing cover crop. Therefore, our objectives of this study were to: 1) provide an overview of …