Digital Commons Network^™

Development Of Computational Methods For Electronic Structural Characterization Of Strongly Correlated Materials: From Different Ab-Initio Perspectives, Uthpala K. Herath

Graduate Theses, Dissertations, and Problem Reports (ETD)

The electronic correlations in materials drive a variety of fascinating phenomena from magnetism to metal-to-insulator transitions (MIT), which are due to the coupling between electron spin, charge, ionic displacements, and orbital ordering. Although Density Functional Theory (DFT) successfully describes the electronic structure of weakly interacting material systems, being a static mean-field approach, it fails to predict the properties of Strongly Correlated Materials (SCM) that include transition and rare earth metals where there is a prominent electron localization as in the case of d and f orbitals due to the nature of their spatial confinement.

Dynamical Mean Field Theory (DMFT) is …

Cycle Decomposition For Integral Current Homology, Kristin Julia Duling

Graduate Theses, Dissertations, and Problem Reports (ETD)

A standard graph theoretical result states that every element of the cycle space of a graph has a cycle decomposition. Georgakopoulos expands this result to a primitive decomposition and minimal representation of each element in a modified 1-dimensional singular homology. We modify the m-dimensional integral current homology in order to ensure a primitive decomposition for each element.

Machine Learning Based Real-Time Quantification Of Production From Individual Clusters In Shale Wells, Ayodeji Luke Aboaba

Graduate Theses, Dissertations, and Problem Reports (ETD)

Over the last two decades, there has been advances in downhole monitoring in oil and gas wells with the use of Fiber-Optic sensing technology such as the Distributed Temperature Sensing (DTS). Unlike a conventional production log that provides only snapshots of the well performance, DTS provides continuous temperature measurements along the entire wellbore.

Whether by fluid extraction or injection, oil and gas production changes reservoir conditions, and continuous monitoring of downhole conditions is highly desirable. This research study presents a tool for real-time quantification of production from individual perforation clusters in a multi-stage shale well using Artificial Intelligence and Machine …

A Domain Adaptation Approach For Segmenting Cell Instances In Microscopy Data, Matthew R. Keaton

Graduate Theses, Dissertations, and Problem Reports (ETD)

Automated cellular instance segmentation is a process that has been utilized for accelerating biological research since before the deep learning era, and recent advancements have produced higher quality results with less effort from the biologist. Most current endeavors focus on completely cutting the researcher out of the picture by generating highly generalized models. However, these models invariably fail when faced with novel data and effectively opt to miss out on the full capabilities of deep learning in pursuit of this goal. In our work, we demonstrate how, with even a minimal amount of annotated data, dominant approaches in this space …

Electrochemical And Mass Spectrometry Methods For Identification Of Gunshot Residues (Gsr) In Forensic Investigations, Kourtney A. Dalzell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Gun violence continues to be one of most significant challenges straining the USA society causing thousands of human lives lost every year. In 2020 alone, firearm-related incidents including homicide, accidents, and suicides, reached a staggering number of over 43,000.^1,2 With the increase in these types of incidents, several service areas in crime laboratories are heavily impacted by the number of cases run on a yearly basis. These include firearm examinations, gunshot residue (GSR) analysis, bullet hole identification, and shooting distance determination, which are crucial to support a criminal investigation and, overall, the justice system in our country. These areas …

Simulated Annealing Heuristics For The Dynamic Generalized Quadratic Assignment Problem, Yugesh Dhungel

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Dynamic Generalized Quadratic Assignment Problem (DGQAP) is the task of assigning a set of facilities to a set of locations in a multi-period planning horizon such that the sum of the transportation and assignment/reassignment costs is minimized. The facilities may have different space requirements, and the capacities of locations may vary during the multiple-period planning horizon. Also, multiple facilities may be assigned to each location without violating the space capacity of the location. This research presents a formulation and applications of DGQAP in various layout and assignment problems encountered in the literature. Two Simulated Annealing (SA) metaheuristics named SA …

Identifying And Minimizing Sources Of Variability Within Modern Spectroscopic Techniques For The Forensic Analysis Of Glass, Oriana Christy Ovide

Graduate Theses, Dissertations, and Problem Reports (ETD)

Broken glass is a trace material frequently found at crime scenes such as hit-and-runs, burglaries, assaults, and homicides. Existing research encompassing the forensic analysis of glass evidence is vast. Published studies cover the analysis and interpretation of various types of glass. However, organizations such as the National Institute of Justice (NIJ), National Institute of Standards and Technology Organization of Scientific Area Committees (NIST-OSAC), and American Society of Trace Evidence Examiners (ASTEE) continue to identify glass-specific research needs to strengthen the scientific foundations of the field. Current gaps within the forensic glass community involve understanding modern glass formulations, re-evaluating the performance …

A Tool For Biometric Interpretation Of Forensic Str Dna Profiles, Ahmad Jamal Baroudi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Rapid DNA biometric identification applications are becoming more essential and widely used in human identity validation processes. Despite their powerful identification capabilities, processing a sample to generate a forensic DNA profile still takes longer compared with other rapid biometric technologies. Methods used to speed up the analysis could lead to signal artifacts similar to those arising from low copy or degraded DNA samples, making the electropherogram unsuitable for forensic interpretation and analysis. The goal of this research effort is to apply biometrics and mathematical approaches to forensic STR (Short Tandem Repeat) profiles. To accomplish this goal, a multi-function software tool …

Inferential Statistics And Information Theoretical Measures: An Approach To Interference Detection In Radio Astronomy, Morgan R. Dameron

Graduate Theses, Dissertations, and Problem Reports (ETD)

In a time when technology is rapidly growing, radio observatories are now able to expand their computational power to achieve higher receiver sensitivity power and a more flexible realtime computing approach to probe the universe for its composition and study new astronomical phenomena. This allows searches to go deeper into the universe, and results in the recording of massive quantities of observed data. At the same time, this increases the amount of radio frequency interference (RFI) found in the obtained observatory data. The high power of RFI easily masks the low power of extraterrestrial signals, making them hard to detect …

Structural And Petrologic Insights Into The Emplacement Of Effusive Silicic Lavas: Inyo Domes, California, Shelby L. Isom

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Long Valley volcanic region, eastern California, USA is most famous for the caldera-forming eruption which produced the Bishop Tuff ~760,000 years ago. Over the last 3,000 years volcanism has been focused in the western margin of the region through punctuated eruptions of silicic lavas and domes. Three simultaneous effusive silicic eruptions, ~600 years ago, generated three lava domes: Obsidian Dome; Glass Creek Dome; and Deadman Dome which erupted onto vastly different topographies. These domes are exceptionally unique as they erupted variable amounts of two textural and chemical endmember lavas (crystal-rich and crystal-poor) that intimately mixed. The overarching goal of …

Design And Development Of A Novel Launch System With Energetic Materials For Unstable Free-Flight Testing, Steven Christopher Mccallister

Graduate Theses, Dissertations, and Problem Reports (ETD)

Characterizing the behavior of highly unstable bodies in flight presents a variety of engineering challenges. Free-flight testing with scale models provides an efficient and economical solution to this problem. This test method requires a means of launching the test model, undamaged, at the desired velocity. The objective of this research was to develop a launch system which incorporates the use of energetic materials for free-flight testing of a model flight vehicle of predetermined mass and dimensions. A high-low pressure gun system was selected for the launcher design, as this system is capable of launching relatively high masses in the velocity …

Association Of Early Life Stressors With Deficits In Child And Adolescent Cognitive Functioning, Emily M. Deming

Graduate Theses, Dissertations, and Problem Reports (ETD)

The purpose of this study was to determine whether the ACEs questionnaire could be a viable screener tool for identifying children in need of neuropsychological testing. This study consisted of a sample of child participants aged 8-17 years (N=53) who were divided into a no ACEs group or the ACEs group (1 or more ACEs) depending on parental responses to the ACEs questionnaire. Participants completed a series of virtual neuropsychological tests that assessed overall neurocognitive functioning, memory, and attention. No significant differences between the no ACEs group and the ACEs group in performance of the overall Neurocognitive Index, …

An Analysis On Adversarial Machine Learning: Methods And Applications, Ali Dabouei

Graduate Theses, Dissertations, and Problem Reports (ETD)

Deep learning has witnessed astonishing advancement in the last decade and revolutionized many fields ranging from computer vision to natural language processing. A prominent field of research that enabled such achievements is adversarial learning, investigating the behavior and functionality of a learning model in presence of an adversary. Adversarial learning consists of two major trends. The first trend analyzes the susceptibility of machine learning models to manipulation in the decision-making process and aims to improve the robustness to such manipulations. The second trend exploits adversarial games between components of the model to enhance the learning process. This dissertation aims to …

Influence Of Saturation Nonequilibrium And Variable Operation Conditions On The Electromechanical Performance Of Ionic Polymer Metal Composite Actuator Architectures, Allison Maria Arnold

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electroactive polymers (EAPs) continue to gain attention for their potential to offer unique and versatile solutions in the soft robotic and flexible electronic industries. Ionic Polymer-Metal Composites (IPMCs) are a class of ionic-type EAPs which can be configured as capacitor actuators with very low voltage requirements (≤ 5 V AC or DC). Their compact, portable, and lightweight properties, coupled with a biomimetic bending actuation response make them ideal for human-machine integrated technologies such as medical implants, active skins, and artificial muscles. The Nafion-based IPMC can be described as a layered composite capacitor containing an ionic polymer core, sandwiched between chemically …

Exploring Cyberterrorism, Topic Models And Social Networks Of Jihadists Dark Web Forums: A Computational Social Science Approach, Vivian Fiona Guetler

Graduate Theses, Dissertations, and Problem Reports (ETD)

This three-article dissertation focuses on cyber-related topics on terrorist groups, specifically Jihadists’ use of technology, the application of natural language processing, and social networks in analyzing text data derived from terrorists' Dark Web forums. The first article explores cybercrime and cyberterrorism. As technology progresses, it facilitates new forms of behavior, including tech-related crimes known as cybercrime and cyberterrorism. In this article, I provide an analysis of the problems of cybercrime and cyberterrorism within the field of criminology by reviewing existing literature focusing on (a) the issues in defining terrorism, cybercrime, and cyberterrorism, (b) ways that cybercriminals commit a crime in …

Bayesian Methods For Multi-Messenger Analysis Of Supermassive Black Hole Binaries: Pulsars And Quasars And Gravitational Waves, Oh My!, Caitlin A. Witt

Graduate Theses, Dissertations, and Problem Reports (ETD)

Supermassive black hole binaries (SMBHBs) can lurk, often unseen, in the centers of post-merger galaxies, and pulsar timing arrays (PTAs) are rapidly approaching the sensitivities required to detect nanohertz gravitational waves (GWs) from these giant pairs. Independently, numerous electromagnetic surveys are seeking evidence of these dynamic duos’ effects on their host galaxies by searching for periodicities in time-domain observations. Combining these two methods to use multi-messenger techniques allows us to learn more about these binaries than using one messenger alone. In this thesis, we have created Bayesian methods to search for SMBHBs using electromagnetic observations of quasars and through GW …

Characterization And Coherent Spin Selective Manipulation Of Quantum Dot Energy Levels, Tristan Anthony Wilkinson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Semiconductor quantum dots (QDs) are promising candidates to fulfill a wide range of applications in real-world quantum computing, communication, and networks. Their excellent optical properties such as high brightness, single-photon purity, and narrow linewidths show potential utility in many areas. In order to realize long term goals of integration into complex and scalable quantum information systems, many current challenges must be overcome. One of these challenges is accomplishment of all necessary computing operations within a QD, which might be enabled by coherent manipulation of single QD energy level structures. In the realm of scalability for quantum devices, a way to …

Similitude, Scaling, And Prediction Of Stream Dissolved Oxygen Across The Contiguous U.S., Aron Gebreslase

Graduate Theses, Dissertations, and Problem Reports (ETD)

Dissolved oxygen (DO) is a general indicator of stream water quality and ecosystem health. However, the concentration of in-stream DO is controlled by various climatic, land use/cover, hydrologic, biochemical, and ecological drivers. Observational data for stream DO are often unavailable at the desired temporal and spatial scales. Accurate and reliable prediction of stream DO concentration based on a small set of environmental drivers is important to guide the water managers and policymakers to achieve and maintain healthy streams. This dissertation focused on identifying the dominant controls of stream DO and understanding the mechanisms and environmental regimes by employing machine learning, …

Tandem Addition/Fragmentation Reactions Of Vinylogous Acyl Sulfonates, Kristen S. Nerbecki

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fragmentation methodology has been used in organic synthesis to produce complex organic compounds. This work is focused on fragmentation reactions leading to the subsequent construction of neopentylene-fused carbocycles, which are found in several important natural products and are difficult to prepare. These are produced by utilizing an optimized fragmentation methodology from the Dudley group. The methodologies build starting materials called nonaflates and triflates with a gem-dimethyl substituent that is seen in many natural products. Nonaflates and triflates are similar in structure, but nonaflates pose benefits that are an advantage over triflates, like cost effective synthesis and more stable compounds. A …

Modeling Post-Crisis Monetary Policy, James Dean

Graduate Theses, Dissertations, and Problem Reports (ETD)

Chapter 1, co-authored with Scott Schuh, examines whether the Taylor Rule still adequately captures monetary policy despite unconventional monetary policies (UMP) and the policy rate near zero in 2009-2015. We find structural breaks at 2007:Q3 in macro models with a shadow funds rate. Taylor Rule coefficients shift back toward pre-1984 estimates and breaks occurred in non-policy parameters. Results are similar with the effective funds rate, so either breaks are not due to UMP or the shadow rate is an insufficient specification of UMP. Chapter 2 incorporates the term structure and the Fed’s average inflation targeting (AIT) framework into the model …

New Techniques In Celestial Mechanics, Ali Abdulrasool Abdulhussein

Graduate Theses, Dissertations, and Problem Reports (ETD)

It is shown that for the classical system of the N body problem ( Newtonian Motion), if the motion of the N particles starts from a planar initial motion at t=t_{0}, then the motion of the N particles continues to be planar for every t\in[t_{0},t_{1}], assuming that no collisions occur between the N particles. Same argument is shown about the linear motion, namely, for the classical system of the N body problem, if the motion of the N particles starts from a linear initial motion at t=t_{0}, then the motion of the N particles continues to be linear for every …

Novel Modes Of Synchronization And Extreme Events In Coupled Chemical Oscillators, David Allen Mersing

Graduate Theses, Dissertations, and Problem Reports (ETD)

We experimentally and computationally investigate dynamical behaviors in coupled chemical oscillators. These networks of chemical oscillators are created using catalytic Ru(bpy)₃²⁺ loaded cation exchange beads submerged in catalyst-free Belousov-Zhabotinsky (BZ) solutions. Various network structures are created by utilizing the photosensitive nature of the Ru(bpy) ₃²⁺ catalyst. The response of the oscillators due to light stimuli can be characterized by constructing a phase response curve (PRC). The PRC quantifies the excitatory and inhibitory responses of BZ oscillators due to applied light perturbations as a function of the oscillators' phase. Different initial concentrations of reactants in the BZ reaction …

A Study On Supereulerian Digraphs And Spanning Trails In Digraphs, Omaema A. Lasfar

Graduate Theses, Dissertations, and Problem Reports (ETD)

A strong digraph D is eulerian if for any v ∈ V (D), d+D (v) = d−D (v). A digraph D is supereulerian if D contains a spanning eulerian subdigraph, or equivalently, a spanning closed directed trail. A digraph D is trailable if D has a spanning directed trail. This dissertation focuses on a study of trailable digraphs and supereulerian digraphs from the following aspects.

1. Strong Trail-Connected, Supereulerian and Trailable Digraphs. For a digraph D, D is trailable digraph if D has a spanning trail. A digraph D is strongly trail- connected if for any two vertices u and …

The Lived Experiences Of Selected Choral Directors During The Covid-19 Pandemic, Angela Berna Milliren

Graduate Theses, Dissertations, and Problem Reports (ETD)

The shift to online education during the COVID-19 pandemic found secondary choral teachers moving traditional performance-based courses to the online venue. The pedagogical changes needed include implementing technology and disseminating information through learning management systems. Relationships between teachers and students, and teachers and colleagues, were challenged with the physical distance of quarantines in the Spring of 2020. This dissertation research project examined the difficulties six teachers faced concerning technology and relationships. I sat down for semi-structured interviews with six colleagues where I asked about their backgrounds, relationships with students and fellow colleagues, and the changes the pandemic brought to their …

Appalachian Adolescents In An Out-Of-School-Time Program: Examining The Role Of Social Support From Family And Friends For Coping Skills And Intellectual Risk-Taking Outcomes, Summer Kuhn

Graduate Theses, Dissertations, and Problem Reports (ETD)

Research on young adults has emphasized the importance of social support for generating positive physical, mental, and academic outcomes. This study aims to understand the impact of social support from family and friends on coping skills and intellectual risk-taking among high school seniors participating in an Out-of-School-Time (OST) program in Appalachia. Data from the program’s annual evaluation (2014-2018) was analyzed to measure associations between perceived social support from family and friends and students’ coping skills and intellectual risk-taking. Moreover, potential differences in these associations across genders were considered. Analyses found a significant association between family-based social support and coping skills, …

Modeling, Fabrication, And Characterization Of Rf-Based Passive Wireless Sensors Composed Of Refractory Semiconducting Ceramics For High Temperature Applications, Kavin Sivaneri Varadharajan Idhaiam

Graduate Theses, Dissertations, and Problem Reports (ETD)

Real-time health monitoring of high temperature systems (>500^oC) in harsh environments is necessary to prevent catastrophic events caused by structural failures, varying pressure, and chemical reactions. Conventional solid-state temperature sensors such as resistance temperature detectors (RTDs) and thermocouples are restricted by their operating environments, sensor dimensions and often require external power sources for their operation. The current work presents the research and development of RF-based passive wireless sensing technology targeting high temperatures and harsh environmental conditions. Passive wireless devices are generally classified as near-field and far-field devices based on the interrogation distance. Near-field sensors are placed at …

Ion Velocity Distribution Functions In Cutting-Edge Plasmas, Mitchell Cameron Paul

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cutting-edge plasma experiments continue to push the frontiers of plasma science. Two such groups of experiments, helicon sources and laboratory magnetic reconnection, are the focus of this thesis. The relatively high plasma density achieved for modest input powers makes helicon source plasmas ideal testbeds for fusion-relevant phenomena without the complexities associated with fusion devices. Examples include plasma-material interaction (PMI) studies, divertor region studies, and boundary physics studies. As advancements in helicon source design and technology make operation at higher power for longer times possible, understanding of the plasma dynamics, particularly ion dynamics, is vital.

Laboratory experiments are essential to advancing …

Development And Testing Of A Biochar Combustor For A Stirling Engine, Kyle Bryant Vickery

Graduate Theses, Dissertations, and Problem Reports (ETD)

Nonrenewable resources persist as a necessity for perpetuating the current technology and standards of living maintained throughout the world. Biochar is an alternative and renewable fuel source that constitutes the potential to provide energy comparable to coal. Designing and fabricating components that can efficiently harness biochar’s energy to power machinery would demonstrate a successful renewable energy source. The scope of this research is to explain the feasible design, fabrication, and results of technology involving the burning of biochar and transference of hot combustion products for the purpose of powering a Stirling Engine. This design consists of a solid fuel burner, …

Pathfinding Fast Radio Bursts Localizations Using Very Long Baseline Interferometry, Pranav Rohit Sanghavi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fast radio bursts (FRBs) are millisecond-duration, bright radio transients of extragalactic origin. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope’s CHIME/FRB instrument and other radio telescopes across the globe have detected hundreds of FRBs. Their origins are a mystery. Precise localization within the host is critical to distinguish between progenitor models. This can be achieved through Very Long Baseline Interferometry (VLBI). Until now, VLBI localizations have only been carried out in targeted follow-up observations of some repeating sources which comprise a small fraction of the FRBs.

For this work, an interferometric array of 6m dishes was constructed at the Green …

Evaluating The Validity And Reliability Of Textile And Paper Fracture Characteristics In Forensic Comparative Analysis, Zachary Bailey Andrews

Graduate Theses, Dissertations, and Problem Reports (ETD)

In a comparative forensic analysis, an examiner can report that a physical fit exists between two torn or separated items when they realign in a manner unlikely to be replicated. Due to the common belief that it is unlikely that two unrelated fractured objects would match with distinctive characteristics, a physical fit represents the highest degree of association between two items. Nonetheless, despite the probative value that this evidence could have to a trier of fact, few studies have demonstrated such assumptions' scientific validity and reliability. Moreover, there is a lack of consensus-based standard protocols for physical fit comparisons, making …