Physical Sciences and Mathematics Commons^™

Fundamental Studies Of Optical Properties And Electrocatalytic Properties Of Low Dimensional Nanomaterials Carbon Nano Dots And 2d Transition Metal Dichalcogenides, Nadeesha Kothalawala

Theses and Dissertations--Chemistry

Low dimensional nanomaterials are widely used in a variety of applications such as opto-electronics, energy production and storage, and bio-medical applications due to their unique optical, catalytic, electronic, and mechanical properties. Most of the nanomaterials offer a plethora of modifications in their structure, composition, morphology, and dimensionality that can lead to the manipulation of their physiochemical properties. This dissertation presents insight into two types of compelling nanomaterials: carbon nanodots (CND) and transition metal dichalcogenides (TMD), investigating their optical and electrocatalytic properties respectively.

Carbon nanodots (CND) are a promising class of photoluminescent nanomaterials that hold a significant potential in many optoelectronic …

Investigating The Behavior Of Redox–Active Organic Molecules In Electrochemical Energy Storage Through Experiment–Guided Computational Simulations, Anton Perera

Theses and Dissertations--Chemistry

The long–anticipated implementation of using renewable sources such as solar and wind to meet the world’s energy demand is still limited by not having appropriate grid–level energy storage systems on a global scale. When considering grid–scale energy storage solutions, environmental concerns, and techno–economic viability play a crucial role in the practical implementation of such technology. To address this, redox–active organic molecules (ROMs) have been explored for many uses including serving as redox–active molecules in redox flow batteries (RFBs) and providing overcharge protection in lithium–ion batteries (LIBs).

Nevertheless, in order to be a major player in electrochemical energy storage, further optimization …

Impacts Of Key Degradation Byproducts On Amine Scrubbing For Post-Combustion Carbon Capture, Thomas Jorgensen

Theses and Dissertations--Chemistry

The increasing atmospheric CO₂ concentration causes significant concern about global warming and its environmental impact. Industrial sectors, including power generation, transportation, and production factories, contribute most of the anthropogenic sources of CO₂ emissions. Researchers search for methods to mitigate these CO₂ emissions without compromising the benefits of industrial processes, including CO₂ capture, utilization, and sequestration (CCUS). Post-combustion carbon capture (PCCC) by amine scrubbing is the most technology ready CCUS, with various pilot-scale projects worldwide showing small-scale to fully operational plants. While researchers have made significant progress in amine scrubbing, they strive to improve the efficiency and …

Addition Reactions Of Olefinic Heterocycles And 4-Hydroxycoumarins, Benjamin Goka

Graduate Research Theses & Dissertations

The work outlined in this dissertation describes acid-base catalyzed projects facilitating the construction of key synthetic analogs with vast therapeutic applications. Three major projects have been covered demonstrating various synthetic routes developed by our research group to furnish key derivatives of heterocyclic compounds, including coumarins, carbohydrate moieties, and beta-lactams. By their catalytic nature, acids, and bases are known to enhance the reactivities of compounds. This allows synthetic chemists to design or chart new and better reaction pathways leading to the delivery of desired reaction products. The first chapter features a summary of the main concepts underpinning the projects.

Chapter 2 …

Superelectrophile Promoted Syntheses Of Aromatic Spirocycles, Jeffrey Caz Ferreira

Graduate Research Theses & Dissertations

Aromatic spirocycles are crucial organic scaffolds that are at the forefront of innovation in various fields of organic electronics, as well as in drug design. The synthesis of these compounds is challenging, especially on an industrial scale and often have suboptimal yields in many traditional syntheses. New synthetic methodologies are being continually explored for the installation of sp3 hydridized spiro junctions. Our research group, as well as other groups, have done exploration of using superelectrophilic synthetic routes that are nicely applied to the formation of aromatic spirocycles. Most relevant to the results discussed in this dissertation are condensation chemistry using …

Magnetotransport Properties Of Dirac Semimetal Taco2te2 And Ferromagnetic Weyl Semimetal Co3sn2s2, Samuel Pate

Graduate Research Theses & Dissertations

This dissertation investigates the magnetotransport properties of topological semimetals, specifically focusing on the Dirac semimetal TaCo2Te2 and the Weyl semimetal Co3Sn2S2. In TaCo2Te2, I observed extremely large magnetoresistance that violates Kohler’s rule. Extended Kohler’s rule can be applied with a calculation of Hall factor at low temperatures. I also explored the applicability of the two-band and four-band models of carrier analysis and correlate the region where Kohler’s rule is obeyed to the four-band model. In Co3Sn2S2, I explored the angle-dependent anomalous Hall effect (AHE) near the Kagome plane, revealing a tunable AHE under applied fields and an abrupt disappearance of …

Exploring The Connection: Field Ecology Research And Student Wellbeing, Elizabeth Small

Graduate Research Theses & Dissertations

Field work is essential in ecological research, offering the opportunity to gather firsthand data, observe natural processes, and deepen our understanding of ecosystems. In my study on small mammal trophic niche dynamics, I investigate how small mammals—critical players in grassland food webs—adapt their diets in response to environmental disturbances. By examining the drivers of variation in trophic niche among three common small mammal species, I aim to uncover how these animals coexist despite similar dietary requirements. Understanding these dynamics is critical for informing global conservation efforts, especially as we work to reverse the biodiversity crisis and restore damaged ecosystems.However, the …

Explicitly Counting Subspaces Of Given Height Defined Over A Field Of Rational Functions, Kakoli Bhuyan

Graduate Research Theses & Dissertations

A height function measures the complexity of mathematical objects, usually points on some projective variety. There are previous results that estimate the number of subspaces of bounded height defined over number fields and function fields over a finite field. These results are asymptotic estimates as the height bound tends to infinity. In this dissertation we derive an explicit counting of the number of subspaces of given height defined over a field of rational functions.

Estimation Of Methyl Orange Dye's Molar Absorptivity Using A Photoresistor-Based Photometer, Patricia M. Ludovice, Ramon M. Delos Santos

Physics Faculty Publications

The need to further develop solar cell technology, particularly on dye-sensitized solar cells (DSSCs), drives absorption studies of various chemical species. In this study, absorbance analysis of methyl orange (MO) dye was performed using the adapted and modified photoresistor-based photometer of Adams-McNichol et al. [1]. The research aims to improve the stability of the reference setup, while maintaining the accuracy of absorbance results it yields. The methodology includes photometer fabrication, MO dye sample preparation, and the evaluation of MO dye's molar absorptivity in an aqueous solution. Results show that the estimated molar absorptivity of MO using the voltage readings from …

Advancements In Nuclear Magnetic Resonance, Electron Paramagnetic Resonance, Multipole Moments, And Lie Group Proprieties, Zhichen Liu

Graduate Thesis and Dissertation 2023-2024

To accurately solve the general nuclear spin state function in Nuclear Magnetic Resonance (NMR), a rotation wave approach was employed, allowing the reference frame to rotate in sync with the oscillating magnetic field. The spin state system was analogously treated as a Rubik's Cube, ensuring the diagonalization of only the time-dependent part of the state function. Although Gottfried's equation (1966) aligns with transitions between specific spin states m and m′, his second rotation contradicts the conservation of angular momentum, resulting in inaccuracies for spin states with initial phase shifts or entangled states. Contrarily, Schwinger (1937) efficiently computed the coefficients for …

Intelligent Traffic Management Systems, Mohammad Mazhar

All Graduate Theses, Dissertations, and Other Capstone Projects

With the increase in population and in particular urban population. The traffic and travel times in between cities and inside cities has increased due to more and more people using private means of transportation. Due to this need arose for tackling the increase in traffic by managing it using various means. For this we look towards The Intelligent Traffic Management System (ITMS). ITMS is an AI-powered solution designed to optimize traffic flow, reduce congestion, and improve overall road safety. The system will monitor real-time traffic data using a combination of cameras and sensors, identify traffic jams, and send alerts to …

Developing A Snow Detection Algorithm Using Spatial Attention For Pedestrian Safety, Ricardo De Deijn

All Graduate Theses, Dissertations, and Other Capstone Projects

SNOW-COVERED SIDEWALKS POSE SIGNIFICANT SAFETY HAZARDS, ESPECIALLY FOR VULNERABLE POPULATIONS SUCH AS THE ELDERLY AND VISUALLY IMPAIRED. THE DEVELOPMENT OF EFFECTIVE SNOW DETECTION SYSTEMS IS CRUCIAL FOR ENHANCING PEDESTRIAN SAFETY. THIS RESEARCH AIMS TO ADDRESS THESE CHALLENGES BY DEVELOPING A SNOW DETECTION ALGORITHM SPECIFICALLY DESIGNED FOR SIDEWALKS. THE PROPOSED ALGORITHM USES A CONVOLUTIONAL NEURAL NETWORK (CNN) ARCHITECTURE INCORPORATING A 2-DIMENSIONAL SPATIAL ATTENTION MECHANISM TO FOCUS ON RELEVANT FEATURES IN IMAGES, IMPROVING SNOW DETECTION ACCURACY. DUE TO THE SEASONAL AND GEOGRAPHIC LIMITATIONS OF SNOW DATA COLLECTION, SYNTHETIC DATA GENERATION USING INVERSE DIFFUSION MODELS WAS EMPLOYED TO AUGMENT THE REAL-WORLD DATASET. ALTHOUGH …

Metaheuristics For White-Box Path Attraction Attacks In Hidden Markov Models, Brandon Koch

All Graduate Theses, Dissertations, and Other Capstone Projects

Hidden Markov Models (HMMs) play a pivotal role in fields such as speech recognition, spam detection, and autonomous vehicles, where reliable predictive capabilities are essential. However, the rapid adoption of HMMs has heightened their susceptibility to adversarial attacks. This research investigates inherent weaknesses in traditional HMMs by examining how adversarial manipulation of observable data impacts model performance. We address three core questions: How does varying HMM parameters influence a path attraction problem? Which metaheuristic methods most effectively optimize these attacks in a white-box scenario? What key vulnerabilities emerge in HMMs under adversarial manipulation? To explore these questions, we design HMMs …

Alfred Russel Wallace Notes 29. Extraterrestrial Entertainment: Are We Being Monitored By Alien Beings?, Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace (1823−1913) was an early advocate for the rational assessment of likelihood of extraterrestrial life. Current efforts to evaluate the situation have ranged from the heavily self-indulgent to the more objective, and it is still often difficult to decide just how much of the information we are receiving on the subject is dependable. An attempt is made here to cut through the haze and reduce the matter to elementals.

Nitrogen Fertilizer Placement And Rate Impacts Sunflower Seed Yield, Oil And Protein Content, Rojina Kafle

Electronic Theses and Dissertations

South Dakota accounts for about 36% of the total US commercial sunflower production and nitrogen is a major input. Costs related to N fertilizer demand economically optimum N rates. This study investigated the impact of the N fertilizer placement method (broadcast vs band) and rate (0, 28, 56, 84, 112, 140 kg N ha-1) on leaf chlorophyll content, head diameter, seed yield, seed oil, and protein concentration of three sunflower hybrids in 2022 and 2023. The experiment was conducted at Brookings (eastern SD- conventional till, 66 cm rainfall) using an oil-type hybrid and at central SD sites (no-till, 57 cm …

Reimagining Hunting Through Women's Decision Space, H. Nash Jackson

Electronic Theses and Dissertations

Approximately 14.4 million people hunt in the United States, yet only 3.1 million (22%) of these hunters are women. To enhance women’s participation, many state natural resource agencies aim to reduce barriers and create pathways for women to hunt. Previously, researchers surveyed women to understand and describe barriers to their full participation in hunting. However, this methodology often just quantifies the different barriers without describing the interconnectedness and how the complexity of barriers can impact women’s participation in hunting. This thesis instead took an inductive research approach with the goal of better understanding women’s perspectives when faced with complex barriers. …

Improving Stream Connectivity In South Dakota, Colton Rainier Curtis

Electronic Theses and Dissertations

Stream connectivity is crucial for fish movement and genetic diversity in fragmented landscapes. Road-crossings often act as barriers, disrupting hydrology and isolating fish populations. The Southeast Aquatic Resources Partnership (SARP) has developed rapid road-crossing assessment protocols and tools to prioritize restoration projects. However, managers lack tools for planning, directing, and initiating roadcrossing assessments. Managers also require modeling approaches to effectively identify and monitor road-crossings across dynamic stream networks. Presented here is a case study offering a roadmap for effective implementation of collaborative road-crossing assessments and prioritization of remediation projects, alongside an exploration of predictive modeling approaches to identify problematic crossings …

Characterizing Mountainous Bedrock Groundwater Systems Across Gradients In Topography And Lithology In Western Montana, David L. Baude

Graduate Student Theses, Dissertations, & Professional Papers

Mountain aquifer groundwater systems remain one of the least understood hydrologic systems in upland hydrology. In this study, we aim to characterize bedrock groundwater system dynamics and bedrock-saprolite interactions across a variety of landscape positions and lithology. We investigate groundwater hydraulics, recharge temperature and elevation, residence times, and bedrock recharge rates across two mountainous headwater catchments in west central Montana. We used a suite of environmental tracers (³H, CFCs, SF₆, and ⁴He) and residence time distribution models to estimate groundwater mean residence times over a range of timescales from decades to millennia. Tracers were sampled …

Snow Spheres And Ice Cubes, John Adam

Mathematics & Statistics Faculty Publications

This article, titled "Snow spheres and ice cubes," discusses the melting of snowballs and ice cubes. It explains that in standard calculus textbooks, it is shown that a snowball melting at a rate proportional to its surface area will have its radius decrease at a constant rate, assuming it remains spherical as it melts. The article then poses several questions related to this concept, including the proportion of a smaller snow sphere that remains when half of a larger one has melted, the value of p for which the smaller sphere first melts, and the volume reduction factor for cubes …

Preface, Mohamed Mahdi Tekitek, Manfred Krafczyk, Li-Shi Luo

Mathematics & Statistics Faculty Publications

[Introduction] Matter, conceptually classified into fluids and solids, can be completely described by the microscopic physics of its constituent atoms or molecules. However, for most engineering applications, a macroscopic or continuum description has usually been sufficient due to the large disparity between the spatial and temporal scales relevant to these applications and the scales of the underlying molecular dynamics. In this case, the microscopic physics merely determines material properties such as the viscosity of a fluid or the elastic constants of a solid. These material properties cannot be derived within the macroscopic framework, but the qualitative nature of the macroscopic …

A Note On Three-Fold Branched Covers Of S4, Ryan Blair, Patricia Cahn, Alexandra Kjuchukova, Jeffrey Meier

Mathematics Sciences: Faculty Publications

We show that any 4-manifold admitting a (g;k₁,k₂,0)-trisection is an irregular 3-fold cover of the 4-sphere whose branching set is a surface in S⁴, smoothly embedded except for one singular point which is the cone on a link. A 4-manifold admits such a trisection if and only if it has a handle decomposition with no 1-handles; it is conjectured that all simply-connected 4-manifolds have this property.

Effect Of Fluid Elasticity On The Emergence Of Oscillations In An Active Elastic Filament, Kathryn G. Link, Robert D. Guy, Becca Thomases, Paulo E. Arratia

Mathematics Sciences: Faculty Publications

Many microorganisms propel themselves through complex media by deforming their flagella. The beat is thought to emerge from interactions between forces of the surrounding fluid, the passive elastic response from deformations of the flagellum and active forces from internal molecular motors. The beat varies in response to changes in the fluid rheology, including elasticity, but there are limited data on how systematic changes in elasticity alter the beat. This work analyses a related problem with fixed-strength driving force: the emergence of beating of an elastic planar filament driven by a follower force at the tip of a viscoelastic fluid. This …

Platform-Independent Estimation Of Human Physiological Time From Single Blood Samples, Yitong Huang, Rosemary Braun

Mathematics Sciences: Faculty Publications

Abundant epidemiological evidence links circadian rhythms to human health, from heart disease to neurodegeneration. Accurate determination of an individual's circadian phase is critical for precision diagnostics and personalized timing of therapeutic interventions. To date, however, we still lack an assay for physiological time that is accurate, minimally burdensome to the patient, and readily generalizable to new data. Here, we present TimeMachine, an algorithm to predict the human circadian phase using gene expression in peripheral blood mononuclear cells from a single blood draw. Once trained on data from a single study, we validated the trained predictor against four independent datasets with …

Topological And Dynamic Properties Of The Sublinearly Morse Boundary And The Quasi-Redirecting Boundary., Jacob D. Garcia, Yulan Qing, Elliott Vest

Mathematics Sciences: Faculty Publications

Sublinearly Morse boundaries of proper geodesic spaces are introduced by Qing, Rafi and Tiozzo. Expanding on this work, Qing and Rafi recently developed the quasi-redirecting boundary, denoted ∂G, to include all directions of metric spaces at infinity. Both boundaries are topological spaces that consist of equivalence classes of quasi-geodesic rays and are quasi-isometrically invariant. In this paper, we study these boundaries when the space is equipped with a geometric group action. In particular, we show that G acts minimally on ∂κG and that contracting elements of G induces a weak north-south dynamic on ∂κG. We also prove, when ∂G exists …

Towards Trust And Reputation As A Service In Society 5.0, Stephan Olariu, Ravi Mukkamala, Meshari Aljohani

Computer Science Faculty Publications

Our paper was inspired by the recent Society 5.0 initiative of the Japanese Government which seeks to create a sustainable human-centric society by putting to work recent advances in technology. One of the key challenges in implementing Society 5.0 is providing trusted and secure services for everyone to use. Motivated by this challenge, this paper makes three contributions that we summarize as follows: Our first main contribution is to propose a novel blockchain and smart contract-based trust and reputation service design to reduce the uncertainty associated with buyer feedback in marketplaces that we expect to see in Society 5.0. Our …

Data Mining Utilizing Various Leveled Clustering Procedures On The Position Of Workers In A Data Innovation Firm, Hussein Alkattan, Noor Razzaq Abbas, Oluwaseun A. Adelaja, Mostafa Abotaleb, Guma Ali

Mesopotamian Journal of Computer Science

The reason of this paper is to clarify dynamic clustering, the divisive and agglomerative dynamic clustering techniques. It fundamentally centers on the concept of the divisive different leveled shapes as well known as the top-down approach by creating a workflow appear, dendrograms, clustered data table which accumulated the clusters based the chosen property, and appear the isolated between each cluster with the assistance of an data mining device called Python. The DIANA dynamic approach utilized data tests of the list of laborers in a Data Advancement firm to induce clusters from the position column inside the data test table. In …

Can Informed Consent Solve Ai Bias?, W. Nicholson Price Ii

Reviews

Artificial intelligence (AI) is moving increasingly rapidly into health care (as indeed into everything else). But it has problems there (as indeed everywhere else!). What’s to be done, in particular, about the deeply embedded biases along racial and other lines that permeate the whole world of health and, as such, are likely to be encoded in AI?

Khiara Bridges gives an answer that seems mild but carries roots of revolution. In Race in the Machine: Racial Disparities in Health and Medical AI, she argues that informed consent is a key lever to pull in fighting these racial disparities. But not …

Environmental Attitudes Of Local Government Scholars In Tiaong, Quezon, Philippines, Justine A. Marasigan, Ma. Larissa Lelu P. Gata

Journal of Public Affairs and Development

This study aimed to analyze the environmental attitudes of local government scholars in Tiaong, Quezon, Philippines. The quantitative research design was used to determine the level of environmental attitudes using the New Ecological Paradigm (NEP) Scale. It was also utilized to examine the relationship between environmental attitudes and independent variables which include demographic characteristics such as age, gender, and economic status, academic background such as student classification, scholastic standing, scholarship privileges, and membership in student and/or youth organizations, and experience with ecological extremes. A total of 301 respondents participated in an online survey administered through Google Forms ®. The respondents …

Critically Interrogating Wolf Eradication And Management Policy Through A Settler Colonial Lens: Toward A Compassionate Future, Karen M. Winter

Antioch University Dissertations & Theses

This largely conceptual multi-article dissertation centers settler colonial theory in a critical interrogation of Wolf eradication and management policy (WEMP) toward the ultimate goal of dismantling injurious structures and systems that brutalize Wolf and other Indigenous animals. Wildlife policy and practice are contemporary manifestations of the long-standing historical project of settler colonialism and its quest for acquisition and ultimate control of Land. Thus, the ongoing hegemonic control of systems of wildlife management and the propensity toward lethal control are also inextricably linked to the oppression of Indigenous worldview about human relationship with the natural world. Settler colonialism, as the nexus …

Actionpoint: An App To Combat Cyberbullying By Strengthening Parent-Teen Relationships, Maddie Juarez, Natali Barragan, Deborah Hall, George K. Thiruvathukal, Yasin Silva

Computer Science: Faculty Publications and Other Works

Overview: Urgent need for intervention tools to mitigate increase in cyberbullying • ActionPoint is based on parent-teen relationship research • App includes interactive modules to improve family communication and online behavior to combat cyberbullying effects • To be presented in the IEEE World Forum on Public Safety Technology 2024.