Physical Sciences and Mathematics Commons^™

High Frequency And Seasonal Controls On Calcium Carbonate Saturation States In Two Maine Estuaries, Catherine Liberti

Electronic Theses and Dissertations

The Gulf of Maine is a highly productive shelf sea in the Northwest Atlantic Ocean that supports many important commercial shellfish. The Gulf of Maine has naturally low calcium carbonate saturation states (𝛀) due to its relatively cold and fresh waters. 𝛀 has been shown to be important predictors of larval and juvenile shellfish growth and mortality. Many of these shellfish species spend all or part of their life cycle within the estuaries that fringe the Gulf of Maine and shellfish aquaculture within the estuaries is increasing rapidly. The 𝛀 of these estuaries are poorly understood, particularly on high frequency …

Local Converse Theorem For 2-Dimensional Representations Of Weil Groups, William Lp Johnson

Electronic Theses and Dissertations

A local converse theorem is a theorem which states that if two representations \chi_1, \chi_2 have equal \gamma-factors for all twists by representations \sigma coming from a certain class, then \chi_1 and \chi_2 are equivalent in some way. We provide a direct proof of a local converse theorem in two distinct settings. Previous proofs published in the literature for these settings were indirect proofs making use of various correspondences between representations of other groups. We first prove a Gauss sum local converse theorem for representations of (F_{p^2})^{\times} twisted by representations of F_p^{\times}. We then apply this theorem to tamely ramified …

Identification Of Conceptual Neighborhoods And Topological Relations In Z2, Brendan P. Hall

Electronic Theses and Dissertations

Topological relations are an essential element of spatial queries and reasoning about spatial information. The predominant model for topological relations in geographic information systems—the 9-intersection—identifies sixteen different relations between groups of pixels (called raster regions) given a set of conditions restricting the composition of the regions interior and boundary. Several of these relations are dependent on the raster region sizes to be realized. An example, ‘Completely Inside' would require raster regions to be sufficiently different in size for one raster to entirely encompass the other. By developing an iterative computational model, this work generates conceptual neighborhood graphs that outlined …

An Interdisciplinary Review: How Rapid Climate Change Is Impacting Human Health, Environmental Policy, And Voter Behavior, Douglas Hasson

Electronic Theses and Dissertations

Preface As an interdisciplinary Ph.D. student at UMaine’s Climate Change Institute, I have an obligation to review a reasonably broad set of applicable climate-related topics, while conducting unique research and tackling specific research questions, problems, and providing substantive conclusions. As such, I have engaged a case study approach where questions specific to the science, policy, and politics of climate change are addressed. Those three case studies are described in more detail below. Background and Context As of July 2023, the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) validates and expands on thousands of peer-reviewed publications and …

Mechanistic Study Of Photochemical And Advanced Oxidation Processes For Degradation Of Pharmaceuticals In Water, Melissa J. Chisholm

Electronic Theses and Dissertations

Pharmaceuticals and personal care products (PPCPs) are contaminants in water worldwide and the effects of the accumulation of these contaminants in the environment are a growing concern. Current water treatment methods involve chlorination and chloramination, which have the potential to create chlorinated by-products that are possibly more harmful than the starting material that was the target of decomposition. Alternative methods to chlorination are advanced oxidation processes (AOP). Previous studies of AOPs often focused on the rate at which the target compound is removed, but neglect to evaluate the by-products.

The compounds of interest in this study were chosen because of …

Evaluation Of Anodes And Modular Membrane-Less Single Cell Reactor Designs For On-Site Hypochlorous Acid Generation, Nelson C. Chime

Electronic Theses and Dissertations

Ensuring safe drinking water and effective sanitation remains a global priority. The shortages of disinfectants experienced during the COVID-19 pandemic further underscore the importance of reliable disinfection methods. Chlorine-based disinfection is widely used but poses safety hazards and logistical challenges in its traditional production and transportation forms. Alternately, on-site chlorine generation using electrochemical conversion of aqueous sodium chloride offers a promising solution, mitigating these risks and providing a flexible approach to disinfection. This thesis investigates the performance of various anode materials and modular, membrane-less, single-cell reactor designs to optimize on-site chlorine generation. Optimization included minimizing specific electrical consumption for chlorine …

Detection And Classification Of Diabetic Retinopathy Using Deep Learning Models, Aishat Olatunji

Electronic Theses and Dissertations

Healthcare analytics leverages extensive patient data for data-driven decision-making, enhancing patient care and results. Diabetic Retinopathy (DR), a complication of diabetes, stems from damage to the retina’s blood vessels. It can affect both type 1 and type 2 diabetes patients. Ophthalmologists employ retinal images for accurate DR diagnosis and severity assessment. Early detection is crucial for preserving vision and minimizing risks. In this context, we utilized a Kaggle dataset containing patient retinal images, employing Python’s versatile tools. Our research focuses on DR detection using deep learning techniques. We used a publicly available dataset to apply our proposed neural network and …

Descriptions Of Interglacial Mastodons From Snowmass, Colorado, Connor White

Electronic Theses and Dissertations

The Ziegler Reservoir fossil site (ZRFS) in Colorado contains over 4000 mastodon bones that date from 140,000 to 100,000 years ago. At an elevation of ~2705 meters above sea level, ZRFS represents an alpine ecosystem dated to Marine Isotope Stage (MIS) 5. Formal descriptions of cheek teeth, mandibles, crania, and femora were completed. Statistical analyses of the upper and lower third molars, including a novel measurement of interloph(id) distances, indicate significant differences between ZRFS mastodons and Mammut pacificus, while falling within the ranges for Mammut americanum. This study agrees with the taxonomic assignment of ZRFS mastodons to Mammut …

Interpreting Shift Encoders As State Space Models For Stationary Time Series, Patrick Donkoh

Electronic Theses and Dissertations

Time series analysis is a statistical technique used to analyze sequential data points collected or recorded over time. While traditional models such as autoregressive models and moving average models have performed sufficiently for time series analysis, the advent of artificial neural networks has provided models that have suggested improved performance. In this research, we provide a custom neural network; a shift encoder that can capture the intricate temporal patterns of time series data. We then compare the sparse matrix of the shift encoder to the parameters of the autoregressive model and observe the similarities. We further explore how we can …

Coastal-Ocean And Estuarine Acidification In Long Bay, South Carolina: A Comparison Of In-Situ Water Quality Monitoring With Measured Carbonate System Parameters, Mary Olsen

Electronic Theses and Dissertations

One of the major water-quality issues impacting our coast and estuaries is coastal-ocean and estuarine acidification. Due to a relative dearth of data in the southeastern United States it is increasingly difficult to determine the full extent and intensity of this problem. This study provides the first characterization of coastal-ocean and estuarine acidification in Long Bay, SC by attempting to leverage long-term water quality data sets at two coastal-ocean pier sites using in-situ YSI EXO sondes deployed at both the surface and bottom waters along with two estuarine sites sampled by volunteer monitors using Orion star multi-meters. Discrete samples (120) …

Development Of A High-Resolution Mid-Infrared Spectroscopy Apparatus For The Study Of Methane And Other Astrochemical Molecules., S M Shah Riyadh

Electronic Theses and Dissertations

This research documents steps towards building a novel spectroscopic technique, namely, cavity-enhanced double-resonance (CEDR) spectroscopy, for investigating methane (CH₄) and other molecules with significance in astrochemistry. These efforts focus on tackling the complexities of their ro-vibrational energy levels and the inefficiencies in analyzing vibrational spectra, particularly for molecules with high symmetry and strong intramolecular interactions. In the CEDR spectroscopy, the first photon, generated by a continuous-wave optical parametric oscillator (CW-OPO) locked to a Doppler-free saturation absorption line, excites the molecule from its ground level to a selected excited ro-vibrational (rotational-vibrational) level, e.g., that of the asymmetric CH-stretch mode. …

Geologic Face Mapping Methodology Utilizing Global Positioning Systems And Unmanned Aircraft Systems, Luke Whitenburg

Electronic Theses and Dissertations

Geologic field mapping has traditionally been a low-technology process, limited by time in the field and a delicate balance between data collection and coverage area. Advancements in Global Positioning Systems (GPS), Unmanned Aircraft Systems (UAS), and software packages offer new tools and techniques for collecting high volume, accurate geologic information. These tools can provide geologists with safe and efficient ways to collect and process greater volumes of field data.

Field data for this study was collected from three open pit mines using a Trimble Geo 7X GPS unit with Geo 7 Series Rangefinder module and a Phantom 4 Pro V2.0 …

Formalization Of A Security Framework Design For A Health Prescription Assistant In An Internet Of Things System, Thomas Rolando Mellema

Electronic Theses and Dissertations

Security system design flaws will create greater risks and repercussions as the systems being secured further integrate into our daily life. One such application example is incorporating the powerful potential of the concept of the Internet of Things (IoT) into software services engineered for improving the practices of monitoring and prescribing effective healthcare to patients. A study was performed in this application area in order to specify a security system design for a Health Prescription Assistant (HPA) that operated with medical IoT (mIoT) devices in a healthcare environment. Although the efficiency of this system was measured, little was presented to …

Sustainable Methodologies For Synthesis Of Small Organic Molecules Using Micellar Catalysis., Deborah Sam Ogulu

Electronic Theses and Dissertations

Organic synthesis is a critical process in the creation of small molecule pharmaceuticals and agrochemicals. However, most methods for synthesizing these small molecules rely on toxic organic solvents as the reaction medium which account for approximately 80% of pharmaceutical waste. Moreover, many catalytic reactions require expensive endangered precious metals like palladium and costly metals. This dissertation presents research that aims to develop sustainable, eco-friendly reaction conditions to address these issues. We developed a ligand-free bimetallic nanocatalyst for the hydrogenation of unsaturated enones. This ligand-free nanocatalyst was prepared from nickel and ppm loading of palladium and was stabilized by harnessing the …

Assessing Sustainability Within The Brewing Industry: A Literature Review And Benchmarking Analysis., Elijah Thomas Miller

Electronic Theses and Dissertations

The goals of this study were twofold: to further examine sustainability within the brewing industry through a literature analysis across four academic journals, and a benchmarking analysis of a Louisville, Kentucky brewery’s resource consumption and emissions production. Publications related to the brewing industry were examined for the presence of sustainability keywords: “efficiency, sustainability, carbon footprint, climate change and greenhouse gas”. Benchmarking examined the local brewery’s primary production facility to determine their performance compared to other surveyed breweries pursuing sustainability across the country. Literature examination found noticeable discrepancies between the appearance of sustainability topics within article abstracts and their discussion within …

Ligand-Stabilized Sno2 As A High-Performance And Scalable Electron Transport Material For Inverted Perovskite Solar Cells., Sashil Chapagain

Electronic Theses and Dissertations

Over the past decade, perovskite solar cell (PSC) technology has attracted significant attention for its low material costs, simple fabrication processes, and impressive photovoltaic performance, with recent power conversion efficiencies (PCEs) surpassing 26%. This advancement marks PSCs as strong competitors to traditional silicon-based photovoltaics. Despite the high efficiency of PSCs, the path to commercialization is hindered by challenges in stability, scalability, and module efficiency. The stability and scalability of PSCs are primarily dependent on the successive charge transfer layers (CTLs) that are interfaced with the perovskite layer. Among CTLs, metal oxide (MO_x) CTLs are preferred for their cost-effectiveness, …

Utilizing Metal Ligand Cooperativity To Activate Small Molecules., Christine Burgan

Electronic Theses and Dissertations

The problems created from the excessive use of fossil fuels can be approached from two directions: capture the CO₂ from the atmosphere or develop alternative energy sources. The current industrial standards for these are environmental and/or health hazards and utilize precious metals, respectively. Metal ligand cooperativity (MLC) has emerged as a promising alternative to using precious metals to activate small molecules. In this dissertation, we focus on a series of metal complexes based on the ligand diacetyl-2-(4-methyl-thiosemicarbazone)-3-(2-hydrazinopyridine) (H₂L¹) for either hydrogen evolution or CO₂ capture. The novel complexes were characterized by ¹H NMR, …

Synthesis And Characterization Of Indole-Based Zinc Dipyrrin Photosensitizers, Jean-Pierre Sanza

Electronic Theses and Dissertations

Metal complexes of dipyrromethene (dipyrrins) used as sensitizers in photocatalysis offer a way to harness solar energy in chemical bonds to create new fuels. This offers the dual role of reducing fossil fuel dependence and atmospheric CO₂ levels. Traditionally, metal dipyrrin complexes are synthesized using substituted pyrroles, aldehydes, and transition metals. Indoles have a more expanded pi-electron system and their dipyrrin-type complex may exhibit visible light absorption, suggesting that they can act as photosensitizers for CO₂ reduction processes. A novel indoledipyrromethene was synthesized using unsubstituted indole and mesitaldehyde. The complex exhibits visible light absorption at 422 nm. Its …

Comparative Analysis Of Surrogate Models For The Dissolution Of Spent Nuclear Fuel, Dayo Awe

Electronic Theses and Dissertations

This thesis presents a comparative analysis of surrogate models for the dissolution of spent nuclear fuel, with a focus on the use of deep learning techniques. The study explores the accuracy and efficiency of different machine learning methods in predicting the dissolution behavior of nuclear waste, and compares them to traditional modeling approaches. The results show that deep learning models can achieve high accuracy in predicting the dissolution rate, while also being computationally efficient. The study also discusses the potential applications of surrogate modeling in the field of nuclear waste management, including the optimization of waste disposal strategies and the …

Depositional Facies And Petrophysical Characterization Of The Leonardian Carbonate (Lower Clear Fork), Tex-Mex, S.E. Field, Central Basin Platform, West Texas, Seyram Nyamasekpor

Electronic Theses and Dissertations

The Lower Clear Fork from Tex-Mex, S.E. Field on the Central Basin Platform is a typical complex reservoir that displays high heterogeneity in lithological and petrophysical properties. The unit represents a producing reservoir succession of Leonardian platform carbonates deposited in shallow marine water during the Early Permian. The sediment of the Lower Clear Fork is composed of a mixed succession of dolomite interbedded with anhydrite, minor clay minerals, and siliciclastics. The high heterolithic nature of the reservoir makes efficient recovery of hydrocarbons difficult. This situation requires an understanding of the variability in depositional facies in terms of mineralogy, depositional textures …

Multithreaded Applications On The Heterogeneous Research Computing Environment., Sungbo Jung

Electronic Theses and Dissertations

Bioinformatics is a domain that has experienced rapid research growth in recent years, as evidenced by the increasing number of articles in biomedical databases such as PubMed, which adds over a million publications every year. However, this also poses a challenge for researchers who need to find relevant citations for their work. Therefore, developing efficient indexing and searching methods for text data is crucial for Bioinformatics. One key technique for information retrieval is document inversion, which involves creating an inverted index to enable efficient searching through vast collections of text or documents. This Ph.D. research aims to design the research …

Multimodal Stylometry: A Novel Approach For Authorship Identification., Glory O. Adebayo

Electronic Theses and Dissertations

This dissertation introduces multimodal stylometry, a novel approach to authorship identification that integrates text and source code features for a comprehensive understanding of an author's unique style. Traditional stylometric methods have primarily focused on either text stylometry or source code stylometry, thereby neglecting the potential insights that multimodality may provide. This research aims to bridge this gap by proposing a framework that combines textual and source code data to enhance the accuracy and reliability of authorship identification. The study begins by reviewing existing literature on authorship identification and stylometry, highlighting the limitations of unimodal approaches. Leveraging recent advancements in multimodal …

Electrochemical Modulation Of Surface Plasmon Wave To Investigate Dna-Based Sensing Platforms And Detection Of Sars-Cov2., Anil Sharma

Electronic Theses and Dissertations

This study offers a thorough comparative analysis of optical and electrical signaling strategies for assessing the electrochemical properties of different redox-labeled DNA-based biosensing platforms. In addition, it illustrates the development of an optical interrogation technique with electrochemical modulation of surface plasmon waves (ECM-SPW) as a route for analyzing and implementing DNA-based hybridization sensors. For those quantitative analyses, we chose a model sensing platform composed of a methylene blue (MB)-modified single-stranded DNA (ssDNA) signaling probe and an unlabeled capture ssDNA probe that complements the signaling probe. Two types of signaling probes were employed in this work: one with MB attached to …

Predicting The Effects Of Precipitation On Groundwater Contamination Near Capped And Uncapped Coal Ash Storage Facilities In Louisville, Kentucky., Daryl Jialiang Chen

Electronic Theses and Dissertations

This study examines the impact of rainfall event characteristics and water table elevations on arsenic and boron contamination in groundwater near two coal ash ponds in Louisville, Kentucky. Utilizing data from 2011 to 2019, the research focuses on both capped and uncapped ponds at Mill Creek and Cane Run sites, employing Threshold Analysis, Regularized Discriminant Analysis (RDA) and Random Forest (RF) to assess contamination levels in groundwater. Analysis shows that capped ponds generally exhibit reduced arsenic levels, though variations exist depending on the contaminant and site. Key predictors such as maximum precipitation and river height were identified, highlighting their significant …

Investigations Of Physical Properties Of Novel Magnetic And Non- Magnetic Two-Dimensional (2d) Alloys., Mohammed Ameen Irziqat

Electronic Theses and Dissertations

This research work reports investigations of structural and physical properties of novel magnetic and non-magnetic 2D alloys. Three techniques were utilized in this investigation: Angle-resolved polarized Raman spectroscopy (ARPRS), Electrical &Thermoelectric power measurements, Magneto-optic Kerr effect (MOKE) spectroscopy. ARPRS and MOKE experiments were constructed during the course of this work. ARPRS was used to study the anisotropy of 2-dimensional black-arsenic phosphors (b-AsxP1-x) as a function of arsenic concentration (x). It was observed experimentally that all Raman modes of the studied samples with x=0, 0.4, 0.8 exhibit polarization dependence. More interestingly, the polarization dependence of Raman modes due to the vibrations …

Strategy-Proof Social Choice Functions On Condorcet Domains., Flannery Marie Musk Wells

Electronic Theses and Dissertations

A social choice function is said to be strategy-proof if no voter has any motivation to lie about their true preference. Strategy-proofness is a desirable property of social choice functions so we consider here functions that always satisfy this property. We add to this property the additional desirable conditions of anonymity and neutrality and present domains on which we can get a characterization of majority rule as the only social choice function that satisfies these three properties. Furthermore, we consider what functions look like when we drop the condition of anonymity.

Using Dynamic Schemas For Query Optimization Over Json Data., Tomas Felipe Llano-Rios

Electronic Theses and Dissertations

Query optimization in document stores has traditionally relied on rule-based approaches, but recent research advocates for a shift towards cost-based optimization. However, this transition is hindered by the fragmented nature of existing approaches, stemming from the early development stage of cost-based query optimization for document databases. A key challenge lies in the absence of a standardized query language and semantics, exacerbated by the diverse and schema-less nature of JSON document collections. To tackle these challenges, the literature has proposed dynamic schemas, primarily utilized at parsing time. However, these schemas lack a formal foundation that describes meaningful semantics for query optimization. …

Assessment Of Method Effects Of Keying And Wording In Instruments: A Mixed-Methods Explanatory Sequential Study, Lin Ma

Electronic Theses and Dissertations

This dissertation presents an innovative approach to examining the keying method, wording method, and construct validity on psychometric instruments. By employing a mixed methods explanatory sequential design, the effects of keying and wording in two psychometric assessments were examined and validated. Those two self-report psychometric assessments were the Effortful Control assessment (Ellis & Rothbart, 2001) and the Grit assessment (Duckworth & Quinn, 2009). Moreover, the quantitative phase utilized structural equation modeling to analyze 2,104 students’ responses and assess the construct of keying and wording. Various hypothetical models were investigated and evaluated. The reliability of each construct in each method was …

The Interplay Of Spin, Charge, And Heat: From Metal/Insulator Heterostructures To Perovskite Bilayers, Sam M. Bleser

Electronic Theses and Dissertations

In this dissertation begin with an investigation of non-local spin transport in an amorphous germanium (a-Ge) sample via the inverse spin Hall effect (ISHE). In that study we show that commonly used techniques such as differential conductance and delta mode of a paired Keithley 6221/2182a for non-local resistance measurements can lead to false indicators of spin transport. Next, we turn out attention to a thickness dependent study in thermally-evaporated chromium (Cr) thin films on a bulk polycrystalline yttrium-iron-garnet (YIG) substrate. This project analyzed the spin transport in the Cr films versus thickness via the longitudinal spin Seebeck effect (LSSE). This …

Thermal, Electrical, And Spin Transport: Encompassing Low-Damping Ferromagnets And Antiferromagnetic/Ferromagnetic Heterostructures, Matthew Ryan Natale

Electronic Theses and Dissertations

Continuing technological advancements bring forth escalating challenges in global energy consumption and subsequent power dissipation, posing significant economic and environmental concerns. In response to these difficulties, the fields of thermoelectrics, spintronics, and spincaloritronics emerge as contemporary solutions, each presenting unique advantages. Thermoelectric devices, based on the Seebeck effect, other a passive, carbon-free energy generating solution from waste heat. Although current thermoelectric technology encounters hurdles in achieving optimal efficiencies without intricate designs or complex materials engineering, recently research into low-damping metallic ferromagnetic thin films have provided a new method to enhance spin wave lifetimes, thus contributing to thermoelectric voltage improvements. As …