Digital Commons Network^™

Graphene/Oxide Interactions With Polymer Networks Modeled Using Molecular Dynamics, Matthew Alan Reil

Electronic Theses and Dissertations

Due to its unique physical properties, graphene has shown great promise as an additive to Polymer Matrix Composites (PMCs) for material property enhancement. Achieving homogeneous dispersion of the graphene platelets within a polymeric network is critical to realizing these enhancements. Research has shown that achieving homogeneous dispersion of graphene platelets within PMCs is challenging as graphene is immiscible with most polymeric networks. This work used Molecular Dynamics (MD) simulations to demonstrate dispersion of graphene platelets within PMCs is inhibited by molecular surface charge potentials. Further simulations were conducted to demonstrate functionalized forms of graphene, specifically graphene oxide, have altered surface …

Urban Informality, Environmental Xenophobia, And Infrastructures Of Citizenship: The Political Lives Of Nicaraguan Migrants In The Informal Settlement Of La Carpio, Costa Rica, Nikolai Alexander Alvarado

Electronic Theses and Dissertations

This dissertation examines urban politics, environmental justice, and infrastructure from the vantage point of South-South migration. It focuses on the work of Nicaraguan migrants living in the informal settlement of La Carpio in San José, Costa Rica, as they negotiate rights in the form of urban services. Nicaraguans in La Carpio have organized politically since 1993 to self-install, demand, and negotiate services such as potable water and electricity. In the process, they successfully compel local authorities to allocate these services and grant them an implicit recognition of their right to remain and live a decent life, regardless of their status. …

Investigating New Methods To Develop Perovskite Solar Cells, Amani Hussain Alfaifi

Electronic Theses and Dissertations

Discovering the potential of organic-inorganic metal halide perovskites (MHP) as a harvesting material in solar cells has strongly affected the research direction in solar energy. The fascinating optical and electronic properties offered by MHP combined with tremendous effort from scientists around the world have improved the efficiency to about 25% in a decade.

In the first part of the dissertation, we studied the lamination process as a new fabrication method for producing self-encapsulated perovskite solar cells based on laminating half stacks,as opposed to the conventional layer-by-layer method. Our work focused on optimizing the lamination process of complex triple cations perovskite …

Microgrid-Enabled Reactive Power Support To Enhance Grid Economics, Sarhan Hasan

Electronic Theses and Dissertations

Reactive power plays an essential role in voltage control and stability in electric power systems. Various Volt/VAR techniques are utilized in electric power systems to maintain the voltage profile within defined acceptable limits and accordingly provide reliability and stability. Reactive power has been commonly generated through large-scale synchronous generators or distributed capacitor banks to provide proper transmission and distribution level system management, however, reactive power can be further used as an effective means to reduce total system operation cost. In this dissertation, an optimal reactive power model is proposed to determine the optimal nodal reactive powers that result in the …

Using Natural Language Processing To Categorize Fictional Literature In An Unsupervised Manner, Dalton J. Crutchfield

Electronic Theses and Dissertations

When following a plot in a story, categorization is something that humans do without even thinking; whether this is simple classification like “This is science fiction” or more complex trope recognition like recognizing a Chekhov's gun or a rags to riches storyline, humans group stories with other similar stories. Research has been done to categorize basic plots and acknowledge common story tropes on the literary side, however, there is not a formula or set way to determine these plots in a story line automatically. This paper explores multiple natural language processing techniques in an attempt to automatically compare and cluster …

Cellular And Developmental Insights Into The Early Evolution Of Muscle, Jeffrey J. Colgren

Electronic Theses and Dissertations

Whereas a great deal has been learned about the molecular underpinnings of morphological evolution in animals, much less is known about the origin of novel cell and tissue types. During the time in which the earliest animal lineages were diversifying, fundamental cell and tissue types, such as muscles, arose. Sponges are one of two animal lineages that lack muscles, yet they undergo coordinated full body contractions. Whereas the signaling processes have been studied, the physical mechanisms of contraction are completely uncharacterized. The main purpose of this work is to understand the primary contractile tissue of the sponge Ephydatia muelleri, …

The Effects Of Adverse Childhood Experiences On Behavioral Outcomes, Jennifer Thomas

Electronic Theses and Dissertations

This study intends to explore the intersection of two vulnerable populations, early childhood development and risks associated with exposure to adverse childhood experiences (ACEs). This study examines how age plays a role in the long-term relationship between ACEs and internal and external behaviors. This study seeks to answer the question of: How does age influence the relationship between number of ACEs and internal and external behaviors? The participants in this study include those aged 0 – 16 from the National Survey of Child and adolescent Well-Being (NSCAW) dataset. The NSCAW study consists of five waves of data where Wave I …

Deep Reinforcement Learning For The Optimization Of Building Energy Control And Management, Jun Hao

Electronic Theses and Dissertations

Most of the current game-theoretic demand-side management methods focus primarily on the scheduling of home appliances, and the related numerical experiments are analyzed under various scenarios to achieve the corresponding Nash-equilibrium (NE) and optimal results. However, not much work is conducted for academic or commercial buildings. The methods for optimizing academic-buildings are distinct from the optimal methods for home appliances. In my study, we address a novel methodology to control the operation of heating, ventilation, and air conditioning system (HVAC).

We assume that each building in our campus is equipped with smart meter and communication system which is envisioned in …

Subalpine Forest Tree Seedling Response To Drought, Alex Goke

Electronic Theses and Dissertations

Knowledge of tree species’ ability to tolerate drought is necessary to anticipate future forest dynamics with climate change, especially at the seedling stage given their role in shaping forest structure. We used precipitation reduction shelters to mimic drought for subalpine conifer seedlings (A. lasiocarpa and P. engelmannii) in the Rocky Mountains and compared survivorship and morphological and physiological responses to assess relative degrees of drought tolerance. We detected no significant investment in morphological tolerance traits (e.g. root biomass, leaf:stem area ratio) but substantial reductions in net photosynthesis. While shading partially ameliorated drought effects when precipitation reduction was moderate, …

Spatial And Temporal Controls On Streamflow Variability In The San Juan Mountains, Colorado, Christopher Lewis Hancock

Electronic Theses and Dissertations

This project characterizes and examines changes to the annual hydroclimatic cycle throughout alpine regions of Colorado with a focus on trends in snowpack and snowmelt hydrology. Datasets analyzed for this research include 79 SNOTEL sites throughout Colorado (24 in the San Juan Mountains) which provide climate metrics for Water Years 1988-2018. Impacts on streamflow are evaluated in the San Juan Region through a network of 11 USGS stream gauges. Correlation matrices and linear regression methods examine the relative controls on the magnitude and timing of discharge, and trend detection using the regional Kendall test quantifies the rate of change within …

The Interplay Between Economic Growth And The Environment: The Case Of China, Christian D. Carpio-Thomas

Electronic Theses and Dissertations

Historically, economic development has come at the cost of environmental degradation. Since the 1980s, neoliberalism rooted in neoclassical theory has dominated mainstream economic thought. The result has been a dramatic increase in environmental degradation in favor of economic growth. The neoliberal recommendations toward development are encapsulated in the Washington and post-Washington Consensuses which promote the liberalization of trade and foreign investment as well as a reliance on market mechanisms. Ultimately, the goal of neoliberalism is to generate growth regardless of the impact that it places on the environment. The case of China presents an example of an economy which pursued …

Ehbp1 And Ehd2 Regulate Dll4 Caveolin-Mediated Endocytosis During Blood Vessel Development, Amelia Margaret Webb

Electronic Theses and Dissertations

During angiogenesis, the development of new blood vessels from existing vessels, there must be tight regulation between a leading tip cell and trailing stalk cells during vascular patterning. Lateral inhibition produced by Notch signaling is central to the specification and maintenance of tip and stalk cells in growing angiogenic sprouts. The Notch pathway is activated by the ligand Delta at adherens junctions between tip and stalk cells. Despite the centrality of Delta/Notch signaling to angiogenesis, relatively little is known about the mechanism of this signaling event. It has been proposed that the force generated by the Notch bound Delta ligand …

Gas Adsorption In Carbon Nanohorns: Equilibrium And Kinetics, Justin Matthew Petucci

Electronic Theses and Dissertations

A study of gas adsorption has been carried out with the focus of better understanding the relationships between the individual properties of the adsorbent/adsorbate (e.g. material structure, interactions, gas size and shape, etc.) and the overall adsorptive properties of the combined system (e.g. capacity, binding strength, equilibration time, etc.) as a function of thermodynamical variables. This is useful from the perspective of a comprehensive and fundamental understanding as well as for practical applications. The equilibrium regime of adsorption on carbon nanostructure materials (nanohorns, nanotubes, and graphite) is investigated using molecular statics (MS) and grand canonical monte carlo (GCMC) methods for …

Automated Change Detection In Privacy Policies, Andrick Adhikari

Electronic Theses and Dissertations

Privacy policies notify Internet users about the privacy practices of websites, mobile apps, and other products and services. However, users rarely read them and struggle to understand their contents. Also, the entities that provide these policies are sometimes unmotivated to make them comprehensible. Due to the complicated nature of these documents, it gets even harder for users to understand and take note of any changes of interest or concern when these policies are changed or revised.

With recent development of machine learning and natural language processing, tools that can automatically annotate sentences of policies have been developed. These annotations can …

Instrument And Application Development In Saturation Recovery And Rapid Scan Electron Paramagnetic Resonance, Joseph E. Mcpeak

Electronic Theses and Dissertations

Enhanced signal sensitivity by the use of Rapid Scan (RS) electron paramagnetic resonance (EPR), a technique that allows for much faster magnetic field scans than traditional field-swept techniques, has facilitated improved data acquisition for many types of samples. For example, irradiated fingernails for radiation dosimetry have been studied using RS-EPR, which resulted in substantial decreases in detection limits. Samarium-mediated reduction mechanisms in organic synthesis have been investigated by RS-EPR providing evidence for a radical intermediate. Spectra of organic radicals exhibiting both narrow lines and closely spaced hyperfine interactions have been recorded via RS-EPR. Well-resolved spectra can be recorded at a …

Characterization Of The Dimerization And Salt Dependent Aggregation Of The Als-Linked Protein Tdp-43, Elizabeth Ehrhardt

Electronic Theses and Dissertations

Trans-active response (TAR) DNA-binding protein 43 (TDP-43) is essential for RNA processing but can also form toxic cytoplasmic inclusions in neurons of patients with amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). RNA-binding has been shown to have the potential to decrease or inhibit the aggregation of TDP-43, indicating that supplying RNA therapeutics may be a solution to treat these neurodegenerative disorders. However, the mechanism of aggregation, transitioning from TDP-43’s native dimeric state to small oligomers to toxic aggregates, is still relatively unknown. This needs to be established before determining how to target and disrupt this aggregation. Using GFP-TDP-43, …

Development Towards An Ethylene Sensing Artificial Metalloenzyme, Mitchell Lee Ellinwood

Electronic Theses and Dissertations

Ethylene (ethene) is the essential ripening hormone for climacteric plants, and consequently its detection and quantification is of considerable interest to the horticulture industry. Its detection however is a non-trivial pursuit, traditionally requiring expensive and inaccessible instrumentation that fail to provide in vivo information about ethylene. A ruthenium based fluorescent probe for the selective detection of ethylene has recently been developed, and it was envisioned that this probe could be made biocompatible by encasing it within a protein scaffold making it an artificial metalloenzyme. To this end biotinylated N-heterocyclic carbenes (NHCs) were synthesized, which can be appended onto the ruthenium …

How Parents, Teachers, Psychologists, And Educational Environments Influence Developmental Transitions Of Preadolescent Twice-Exceptional Students, Karen B. Arnstein

Electronic Theses and Dissertations

The purpose of this collective case study was to examine the perceived developmental transitions of preadolescent, twice-exceptional students to understand both the supports and barriers from the perspective of parents, teachers, and psychologists. The case for this study, located in a western U.S. state, was a private school educating twice-exceptional students. The research questions guiding the study included the following: How do parents perceive growth in both academic and psychosocial development? How do educators perceive growth in both academic and psychosocial development? What are the supports that promote successful developmental transitions? What are the barriers that inhibit successful developmental transitions? …

Is The Reliability Of Objective Originality Scores Confounded By Elaboration?, Shannon Marie Maio

Electronic Theses and Dissertations

The increased use of text-mining models as a scoring mechanism for divergent thinking (DT) tasks has sparked concerns about the ways in which automated Originality scores may be influenced by other dimensions of DT, especially Elaboration. The debate centers around the question of whether too much variance in automated Originality scores is accounted for by the number of words a participant uses in a response (i.e., Elaboration), and, thus, how the influence of Elaboration can affect the reliability of Originality scores. Here, a partial correlation analysis, in conjunction with text-mining and psychometric modeling, is conducted to test the degree to …

Measuring The Connective Action Of Black Lives Matter Activists: A Psychometric Investigation Into Twitter Data, Paige Alfonzo

Electronic Theses and Dissertations

Many protest movements from the last twenty-first century have become increasingly networked and personalized. Several scholars have tapped into this change coining terms such as participatory action, digitally mediated action, computer-mediated communication, issue-based organization, and what I focus on in this project, connective action. Building on the ideas percolating across the literary landscape at the time, Bennett and Segerberg (2012) introduced the logic of connective action based on emergent characteristics they observed in post-2010 large-scale social movements. Both the logic of connective action and related work have become deeply ingrained in today's social movement scholarship. As such, I felt it …

Real-Time Detection Of Demand Manipulation Attacks On A Power Grid, Srinidhi Madabhushi

Electronic Theses and Dissertations

An increased usage in IoT devices across the globe has posed a threat to the power grid. When an attacker has access to multiple IoT devices within the same geographical location, they can possibly disrupt the power grid by regulating a botnet of high-wattage IoT devices. Based on the time and situation of the attack, an adversary needs access to a fixed number of IoT devices to synchronously switch on/off all of them, resulting in an imbalance between the supply and demand. When the frequency of the power generators drops below a threshold value, it can lead to the generators …

Comprehensive Research Synthesis: An Approach To Mixed Methods Research Syntheses, Lilian Linialy Chimuma

Electronic Theses and Dissertations

Mixed methods research synthesis (MMRS) is an emerging application of both mixed-methods research (MMR) and review research. MMRS promises to comprehensively address intricate contemporary research and evaluation questions given diverse evidence sources (across quantitative, qualitative, and MMR primary studies). The significance of concurrently addressing methodological issues for new research developments is widely noted in the literature. Current efforts attempt to streamline methodological practices along with application of the MMRS approach. Researchers have proposed conceptual frameworks to guide the application and practice of MMRS studies. Despite these efforts, complications and disagreements persist. In response to these concerns, this study developed a …

Power System Frequency Control And Stability Analysis With Increasing Renewable Energy Penetration Level, Weihang Yan

Electronic Theses and Dissertations

With the ever-increasing penetration level of renewable energy generation units and the replacement of traditional synchronous generators, the issues associated with the deteriorated performance of power system frequency regulation and potential grid frequency instability become more significant. In this dissertation, the inertial control algorithms are investigated and analyzed for power electronics converter in a renewable energy generation unit. The concept and design of Virtual Synchronous Generator are comprehensively discussed, such that the small-signal stability and frequency stability of power systems with high renewable energy penetration level can be enhanced. Moreover, both nonlinear dynamic model and small-signal linearization of Virtual Synchronous …

The Experiences Of Ncaa Student-Athletes With An Eating Disorder Or Disordered Eating, Rachel E. Taylor

Electronic Theses and Dissertations

The purpose of this study was to explore the experiences of student-athletes who had an eating disorder or disordered eating (ED/DE) while competing for the National Collegiate Athletic Association (NCAA). Integrating criticism and connoisseurship and critical evocative portraiture, four post-collegiate women who participated in cross country and track, who were either clinically diagnosed with an ED/DE or who self-diagnosed, participated in two interviews to describe their experiences with and the impact of ED/DE on their athletic pursuits, academic pursuits, as well as their relationships with coaches, teammates, and family. The analysis of these interviews showed the complexity of this topic. …

Land Use Influences Along Elevation Gradient On Macroinvertebrate Communities, Brittany Sprout

Electronic Theses and Dissertations

Land use activities have caused disturbances that affect the quality of freshwater ecosystems worldwide. How the influences of land use along an environmental gradient and the associated environmental variables that may influence stream diversity and function is unclear. We address these issues by studying biodiversity, abundance, and functional diversity of macroinvertebrates across different land types along a gradient in Colorado, USA. We also address how diversity may change along an elevation gradient by analyzing previously published macroinvertebrate research. We found evidence that land use and disturbance are stronger explanations of changes in macroinvertebrate communities, rather than elevation. Functional trait patterns …

Identification Of Gifted Characteristics Using The Behavioral Assessment Scale For Children—Third Edition, Kristine Zytka

Electronic Theses and Dissertations

Children who are gifted are at-risk for being misidentified with emotional and behavioral disorders (Daniels & Piechowski, 2009; Mullet & Rinn, 2015; Webb, 2016). Challenges exist in conclusively defining giftedness, assessing giftedness, and understanding common behavioral patterns among gifted individuals (Bracken & Brown, 2006; McClain & Pfeiffer, 2012). Because gifted children typically exhibit common behavioral patterns, it is important for school psychologists to understand gifted behavioral characteristics, how to assess these characteristics, and how to differentiate between common gifted behavior and maladaptive behavior (Daniels & Piechowski, 2009; Webb, 2016). This study examined the value of the BASC-3 in identifying gifted …

Deep Siamese Neural Networks For Facial Expression Recognition In The Wild, Wassan Hayale

Electronic Theses and Dissertations

The variation of facial images in the wild conditions due to head pose, face illumination, and occlusion can significantly affect the Facial Expression Recognition (FER) performance. Moreover, between subject variation introduced by age, gender, ethnic backgrounds, and identity can also influence the FER performance. This Ph.D. dissertation presents a novel algorithm for end-to-end facial expression recognition, valence and arousal estimation, and visual object matching based on deep Siamese Neural Networks to handle the extreme variation that exists in a facial dataset. In our main Siamese Neural Networks for facial expression recognition, the first network represents the classification framework, where we …

Certification-Driven Testing Of Safety-Critical Systems, Aiman S. Gannous

Electronic Theses and Dissertations

Safety-critical systems are those systems that when they fail they could cause loss of life or significant physical damages. Since software now is an essential component of these types of systems, failures caused by software faults could come from flaws in the software development life-cycle. As a result, challenges unfold in two directions. First, in verifying that the software will not put the system in an unsafe state, and identifying external failures and mitigate them properly. Second, in providing sufficient evidence for an efficient safety certification process. In this study, we propose an approach for testing safety-critical systems called Model-Combinatorial …

Facial Action Unit Detection With Deep Convolutional Neural Networks, Siddhesh Padwal

Electronic Theses and Dissertations

The facial features are the most important tool to understand an individual's state of mind. Automated recognition of facial expressions and particularly Facial Action Units defined by Facial Action Coding System (FACS) is challenging research problem in the field of computer vision and machine learning. Researchers are working on deep learning algorithms to improve state of the art in the area. Automated recognition of facial action units has man applications ranging from developmental psychology to human robot interface design where companies are using this technology to improve their consumer devices (like unlocking phone) and for entertainment like FaceApp. Recent studies …

Aggregated Der Management In Advanced Distribution Grids, Mohsen Mahoor

Electronic Theses and Dissertations

Evolution of modern power systems are more distinct in distribution grids, where the growing integration of microgrids as well as distributed energy resources (DERs), including renewable energy resources, electric vehicles (EVs), and energy storage, poses new challenges and opportunities to grid management and operation. Rapid growth of distribution automation as well as equipment monitoring technologies in the distribution grids further offer new opportunities for distribution asset management. The idea of aggregated DERs is proposed as a remedy to streamline management and operation of advanced distribution grids, as discussed under three subjects in this dissertation. The first subject matter focuses on …