Digital Commons Network^™

Uncovering Structure-Property Relationships Of Inorganic Nanomaterials Via Transmission Electron Microscopy, Melonie Thomas

Theses and Dissertations--Chemistry

The rapid increase of research in nanoscale devices and nanotechnology in the past few decades has revealed that nanomaterials may possess exceptional properties that are significantly different from the bulk counterpart, due to local rearrangements of the atoms at surfaces and defects. Transmission electron microscopy (TEM) is an indispensable tool when it comes to the characterization of nanomaterials, primarily due to its ability to resolve the local-structure of materials at the atomic-scale. To study dynamic processes, however, regular TEM experiments are inadequate, as they provide only before and after information rather than the real-time data essential to understanding a reaction …

Deconvolution Tools For Extracting Insight From Challenging Two-Flavin Systems, Dallas Michael Bell

Theses and Dissertations--Chemistry

Flavoproteins have long been explored for their ubiquity among a number of metabolic and energetic reactions. The flavin cofactor has the inherent benefit of distinct spectral changes associated with redox transitions; however, the double-edged sword is incurred as these distinct signatures overlap and take up much of the UV-vis spectral range. Therefore, it is crucial to create a method to demarcate the expressed redox transitions for studying these systems. The first portion of these studies discusses the creation of a program that deduces spectra for redox transitions in a single-flavin containing model protein: flavodoxin. The latter portions discuss the application …

Structure, Surface, And Interfacial Modifications Of Carbon And Supported-Metal Electrodes For Electrochemical Carbon Dioxide Conversion, Namal Wanninayake

Theses and Dissertations--Chemistry

Currently, the global emission of greenhouse CO₂ is over 36 billion tons per year. Consequently, the atmosphere's CO₂ concentrations have exceeded 400 ppm, which is the highest reported in the last three million years. The accumulation of CO₂ is the most critical origin for today's climate change; thus, closing the carbon cycle is vital to reverse the detrimental impacts of climate change. Under this goal, the electrochemical reduction of CO₂ into commodity fuels and chemicals via renewable energy is one of the most promising strategies to recycle CO₂. Despite significant progress made in electrocatalysis, …

Local Control Of Resource Allocation Is Sufficient To Model Optimal Dynamics In Syntrophic Systems, Glenn Ledder, Sabrina E. Russo, Erik B. Muller, Angela Peace, Roger M. Nisbet

School of Biological Sciences: Faculty Publications

Syntrophic systems are common in nature and include forms of obligate mutualisms in which each participating organism or component of an organism obtains from the other an essential nutrient or metabolic product that it cannot provide for itself. Models of how these complementary resources are allocated between partners often assume optimal behavior, but whether mechanisms enabling global control exist in syntrophic systems, and what form they might take, is unknown. Recognizing that growth of plant organs that supply complementary resources, like roots and shoots, can occur autonomously, we present a theory of plant growth in which rootshoot allocation is determined …

Predator-Dependent Functional Responses Alter The Coexistence And Indirect Effects Among Prey That Share A Predator, Kyle E. Coblentz, John P. Delong

School of Biological Sciences: Faculty Publications

Predator functional responses describe predator feeding rates as a function of prey abundance and are central to pred-ator–prey theory. Despite ample evidence that functional responses also depend on predator abundance, theory incor-porating predator-dependent functional responses has focused almost exclusively on specialist predator–prey pairs or linear food chains. This leaves a large gap in our knowledge as many predators feed on multiple prey, and in so doing, generate indirect effects among prey that can alter their coexistence. Here we investigate how predator-dependent functional responses in a one predator–two prey model alter the coexistence among prey and their net effects on one …

Elementary School Teacher Characteristics Associated With Self-Efficacy For Using Technology To Implement Constructivist Content Instruction: An Explanatory Correlational Study, Patricia Barton

Graduate Research Theses & Dissertations

Technology mediated constructivist practices may be effective, but there are challenges for implementing them, and one challenge is the teachers themselves and their self-efficacy. Teachers of different backgrounds may differ on self-efficacy in technology mediated constructivist practices, and those possible differences can warrant different training approaches. For this study, 212 K-5 teachers from small to medium sized rural and suburban school districts in the Midwestern US, as well as teachers from a variety of other geographic areas, completed an online survey. The dependent variable self-efficacy in Technological Pedagogical and Content Knowledge (SE-C-TPACK) was regressed on the independent variables. The independent …

Lane Detection Of Autonomous Vehicles Using Clustering And Augmented Sliding Windows Techniques, Keerti Chand Bhupathi

Graduate Research Theses & Dissertations

In this thesis, detection of solid lines and dashed lines of lanes using augmented sliding window technique, clustering technique and combination of both augmented sliding window and clustering is discussed. The lane points are extracted using image processing techniques. The performance of lane detection using these techniques is analyzed. Lanes are simulated in a laboratory for the input data set. The input data set consists of curved lines of dashed and solid lines which split and merge. Further, partially obscured lanes are also tested with the algorithm. The center of the lanes from vehicle to horizon is found based on …

The Efficacy Of Educational Robotics In An Integrated Stem Elementary Curriculum, Colleen Marie Cannon-Ruffo

Graduate Research Theses & Dissertations

While there has never been a greater demand for STEM education, the U.S. is still struggling to define and implement this type of instruction. Identifying innovative and effective ways of improving STEM education in the K-12 environment is vital to the U.S. to remain economically viable on a global level. The multidisciplinary aspect of educational robotics facilitates an integrated approach to STEM learning which espouses the educational theories of Constructionism and Computational Thinking. The purpose of this study was to compare the cognitive and affective out-comes of participation in an integrated STEM curriculum based on educational robotics. The integrated STEM …

A Search For Resonant And Non-Resonant Di-Higgs Production In The Γγbb Channel Using The Atlas Detector, Tyler James Burch

Graduate Research Theses & Dissertations

This dissertation presents a search for resonant and non-resonant di-Higgs production in the γγb ̄b final state using data from the ATLAS detector at the Large Hadron Collider (LHC). The search is performed on 36.1 fb−1 of data from proton-proton collisions at a center-of-mass energy of √s= 13 TeV collected in 2015 and 2016.

No significant excesses are observed in this search. The non-resonant analysis sets limits on the HH→γγb ̄b cross-section times branching ratio, with an upper observed (expected) limit of 0.73 (0.93) pb. The observed (expected) limits on the Higgs boson trilinear coupling at 95% Confidence Level (CL) …

Real-Time Traffic Sign Detection And Classification Based On A Video Feed, Victor Ciuntu

Graduate Research Theses & Dissertations

Autonomous vehicle development is currently progressing at a very fast pace and traffic sign detection and classification has an important role in it. This thesis looks at the history of autonomous vehicles as well as different implementations for traffic sign detection and classification. Multiple possible approaches are analyzed with the final goal of doing this task in real-time using a portable system.

To accomplish this task, the final solution uses a convolutional neural network for detection and classification combined with a custom optical character recognition algorithm for speed limit signs. The optical character recognition algorithm is built from the ground …

An Automated Method For Detecting Water Levels Using Computer Vision And Artificial Intelligence, Priyanjani Chowdary Chandra

Graduate Research Theses & Dissertations

Flooding is one of the most dangerous weather events today. Between 2015-2019, on average, it has caused more than 130 deaths every year in the USA alone. World Health Organization has reported that, between 1998-2017, floods have affected more than 2 billion people worldwide. The devastating nature of flood necessitates the continuous monitoring of water level in the rivers and streams in flood-prone areas to detect the incoming flood. In this thesis, we have designed and implemented a computer vision and AI-based system that continuously detect the water level in the creek. Our solution employs an effective template matching algorithm …

Investigating Achievement And Mental Health Through The Dual-Factor Model, Kelly Clark

Graduate Research Theses & Dissertations

School professionals are charged not only with advancing students’ content knowledge, but also with developing their social and emotional skills; however, adolescence is a period in which many individuals experience declines in academic performance and mental health. The current study investigated associations between grit, academic grit, and growth mindset with academic achievement, subjective well-being, and psychopathology. Second, this study examined the demographic makeup of mental health groups posited by the dual-factor model of mental health, as well as group-level differences in grit, academic grit, growth mindset, and academic achievement across mental health groups identified through latent profile analysis. Adolescents (N …

Environmental Discriminators For Significant Tornadoes And Hail In The U.S. Using Proximity Soundings, Cody Michael Converse

Graduate Research Theses & Dissertations

Over the last 50 years, the United States has experienced an increase in severe storm events that produced $1 billion in damages or greater. Much of this loss is attributed to significant tornadoes and hail associated with deep, moist convection. Improving forecasts for these significant events assist in mitigating the impacts of these events. Previous work has identified statistically significant environmental parameters associated with severe thunderstorms, but more research is needed in identifying statistically significant ingredients associated with environments that produce significant tornadoes and hail.

This thesis aims to answer the following question: “Can diagnostics commonly used to forecast for …

The Synthesis Of Pb2sr2sm1-Xcaxcu3o8 And Characterization Of Its Structural And Superconducting Properties., Deblina Das

Graduate Research Theses & Dissertations

Superconducting lead-based cuprate materials of the 2213 structural type, Pb2Sr2MCu3O8 (M=Sm1-xCax, Y1-xCax, Er1-xCax and Yb1-xCax), were synthesized and characterized using x-ray powder diffraction and the Rietveld structural refinements method. Pb2Sr2Sm1-xCaxCu3O8 single crystals were grown by an optimized flux method using various combinations of PbO/PbF2 solvents. Samples with different Sm/Ca ratios were investigated for their superconducting properties. Magnetic measurements reveal the presence of a transition at 120K. Preliminary x-ray diffuse scattering experiment at the Advanced Photon Source of Argonne National Laboratory demonstrates the high quality of one of our crystals and the presence of rod-like diffuse scattering connecting the Bragg peaks …

Experiences Of Southeast Asians At A Community College In The Midwest, Emmanuel Canlas Esperanza Jr.

Graduate Research Theses & Dissertations

This dissertation explored what contributed to Southeast Asian students’ persistence in an urban community college in the Midwest. A qualitative case study was used to reveal how Southeast Asian students perceived personal and educational experiences and how those experiences created an impact on their persistence. This project addressed the lack of research on Southeast Asians and their challenges attaining academic success in higher education. This study is critical, as there is a lack of research on Southeast Asian students’ experiences within higher education institutions, particularly within community college settings. The majority of research has focused on Asian American or international …

Multi-Component Material For Solar Energy Conversion And Fundamentals Of Lead Acid Batteries, Crystal Ferels

Graduate Research Theses & Dissertations

Synthesis of complex inorganic materials is desirable because their complex composition allows more degrees of freedom and tunability, whose properties differ from their parent components. As an expansion on this concept, we synthesized a quinary compound Ce3FeWS3O6, using a molten flux method and a solvothermal method. The compound crystallizes into a hexagonal crystal system with space group P63/m. Its electric partition shows an anion with the form [(Ce3+)3W6+(S2-)3(O2-)6]3- forcing the transition metal Fe3+ state and leaving no conduction electrons, making the material a semiconductor. This compound is the right candidate as photoelectric material capable of absorbing photons from the solar …

The Emotions Of Science: Using Social Media To Gauge Public Emotions Toward Research Topics, Cole C. Freeman

Graduate Research Theses & Dissertations

Online and in the real world, communities are bonded together by emotional consensus around core issues. Emotional responses to scientific findings often play a pivotal role in these core issues. When there is too much diversity of opinion on topics of science, emotions flare up and give rise to conflict. This conflict threatens positive outcomes for research. Emotions have the power to shape how people process new information. They can color the public's understanding of science, motivate policy positions, even change lives. And yet little work has been done to evaluate the public's emotional response to science using quantitative methods. …

Bi-Objective Optimization For A Single Batch Processing Machine, Leena Omar Ghrayeb

Graduate Research Theses & Dissertations

This research proposes a methodology for solving the problem of scheduling jobs with unequal ready times, unequal processing times, and unequal sizes on a single batch processing machine, with the objectives of minimizing makespan and maximum tardiness. Jobs must be placed into batches and scheduled on the machine such that both objectives are minimized, and machine capacity is not violated. The problem under study can be denoted as 1|p-batch, sj, rj| Cmax,Tmax. Based on a review of relevant literature, this problem has not been considered before.

The problem under study is NP-hard. Consequently, meta-heuristics such as Simulated Annealing (SA) and …

Social Change Leadership Development Associated With Black Greek Letter Organizations (Bglo): Determining How The Divine Nine Bglos Develop Social Change Leaders, Jason Reco Goode

Graduate Research Theses & Dissertations

This study sought to add literature to the topic of Black Greek Letter Organizations (BGLOs) that were part of the National Pan-Hellenic Council (NPHC) by exploring the benefits of BGLO membership related to social change leadership development. There were no studies that explained how BGLOs developed social change leaders. This qualitative study of BGLOs used two 90-minute interviews to gather data about BGLO member’s perceptions regarding their social change leadership development. The literature review provided history on the inception of Greek organizations, founding of BGLOs, the NPHC, non-NPHC Black Greek organizations, Masonic influence, student development, student leadership theories, activism, social …

On The Self-Force Problem Of Point-Like Charged Particles In Classical Electrodynamics, Kevin J. Hamilton

Graduate Research Theses & Dissertations

The problem of a point-like charged particle’s self-interaction force has been along-standing problem in the field of classical electrodynamics. For over a century,physicists have unsuccessfully developed a satisfactory solution until recently. Weexpand on the work done by Gralla et. al. [1] in order to establish a smooth andrelativistically correct formulation of point-like charged particles in motion and shedlight on related problems and applications, particularly the motion of elementary par-ticles with magnetic dipoles through non-uniform static magnetic fields. We conductnumerical simulations in order to quantify the magnitude of the perturbations fromthis self-force due to the new equations of motion relative to …

Experimental And Computational Characterization Of Sodium Nitrate @ Silica Nano Capsules For Thermal Energy Storage Applications, Wataru Hashimoto

Graduate Research Theses & Dissertations

In this investigation, a nanocapsule composed of a sodium nitrate core and a silicon dioxide shell is synthesized, characterized, and analyzed utilizing a mixture of analytical and computational tools. The sol-gel method was selected as the process of nanoencapsulation. Analytical characterization techniques employed in this investigation include differential scanning calorimetry (DSC) to measure melting temperatures and enthalpies of fusion, dynamic light scattering (DLS) to calculate particle size distributions, scanning electron microscopy (SEM) to analyze surface characteristics, transmission electron microscopy (TEM) to perform shell characterization, and energy dispersive X-ray spectroscopy (EDS) to determine chemical composition. Preliminary results indicated a decrease in …

Projective Splitting Methods For Maximal Monotone Mappings In Hilbert Spaces, Oday Hazaimah

Graduate Research Theses & Dissertations

In this dissertation, novel approaches for solving convex nonsmooth optimization, variational inequalities and inclusion problems are studied. The main contributions of the dissertation are given in Chapter 4 and Chapter 5. The two proposed iterations in Chapter 4, Half-Extragradient algorithm (HEG) and its accelerated version, are a natural modification of the classical Extragradient algorithm (EG)

when the composite objective function is a sum of three convex functions. EG evaluates the smooth operator twice per iteration via proximal mappings, and also, it allows larger step sizes. One of the main advantages of the proposed scheme is to avoid evaluating an

extragradient …

Bayesian Approach To Finding The Most Likely Circuit Structure, Shannon Harms

Graduate Research Theses & Dissertations

Systems, and their reliabilities, depend on the reliabilities of the components that theyare composed of, and in this paper we want to nd the system structure that is the most likely given observed data. Bayesian methods were utilized in order to discover the posterior means, or observed reliabilities, of both the components and the systems. Assuming the serial and parallel system structures have independent components, we calculated system reliabilities based on observed component reliabilities by using the multiplication and addi- tion probability rules. We are then able to expand upon the numerical comparison method through a maximum likelihood analysis that …

Remodeled Classrooms: Experiential Learning And Its Impact, Mindy Kinnaman

Graduate Research Theses & Dissertations

This dissertation examined how faculty learn how to host and facilitate experiential learning activities for their classes and how the faculty are impacted by the work. Findings based upon nine semi-structured interviews indicated that fewer than half of participants had been formally trained to host experiential learning activities and some received no training at all. Findings also indicated that faculty experienced several personal benefits to hosting experiential learning activities, as did their students. Recommendations that emerged from this project include training programs for faculty, mentoring programs, and funding of experiential learning programs.

2d Confinement Of Thermal Gradients In Metallic Non-Local Spin Valves, Rachel K. Bennet

Electronic Theses and Dissertations

Non-local spin valves (NLSVs) are a valuable tool in the growing field of spintronics due to their unique ability to separate charge current from pure spin current. Their potential applications as read heads for hard-disk drives, as well as use as logic gates and other spin sensors, makes detailed understanding of their behavior under a wide range of operating conditions very important.

In this dissertation, I present results of extreme thermal engineering of the supporting substrate of NLSVs, which has a dramatic impact on the background signal of the device as well as contributions from thermal spin effects such as …

Satellite Constellation Deployment And Management, Joseph Ryan Kopacz

Electronic Theses and Dissertations

This paper will review results and discuss a new method to address the deployment and management of a satellite constellation. The first two chapters will explorer the use of small satellites, and some of the advances in technology that have enabled small spacecraft to maintain modern performance requirements in incredibly small packages.

The third chapter will address the multiple-objective optimization problem for a global persistent coverage constellation of communications spacecraft in Low Earth Orbit. A genetic algorithm was implemented in MATLAB to explore the design space – 288 trillion possibilities – utilizing the Satellite Tool Kit (STK) software developers kit. …

Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie

Electronic Theses and Dissertations

Drosophila embryogenesis starts with a single nucleus undergo 13 rounds of nuclear divisions called syncytial cycles. Staring at cycle 10 when nuclei migrate to the surface of the embryo, massive and dynamic cortical actin structures and cleavage furrow formations occur. How actin regulators coordinate into an organized network directing three-dimension actin structures in the developing organisms is an unsolved question. Here, I present an in-depth characterization of actin cap dynamics: the actin caps go through expansion, stabilization, elongation and fragmentation phases in each cycle. Arp2/3 is the major contributor to actin cap formation. The functions of 7 different actin and …

K-6 Saudi Arabian Teachers' Implementation Of Electronic Textbooks: Factors Associated With Behavioral Intention, Hamed Alghamdi

Graduate Research Theses & Dissertations

Teaching with digitized textbooks is a relatively new domain of education in general and is a completely new domain in Saudi Arabia. This study investigated the relationship between the Unified Theory of Acceptance and Use of Technology (UTAUT) constructs and the behavioral intention of K-6 elementary school teachers in Jeddah School District in Saudi Arabia to identify predictors of their behavioral intention toward using digitized books in their classrooms. The study employed a modified electronic UTAUT survey for data collection. The results of the study indicated a significant relationship between teachers' behavior intention and the variables of performance expectancy, effort …

Model-Based Estimates Of The Timing Of Brine Flux Into The Victoria Land Basin From The Mcmurdo Dry Valleys, Antarctica, Valerie Nicole Voisin

Graduate Research Theses & Dissertations

Submarine groundwater discharge (SGD) at a continental scale is one of the least constrained components of the hydrologic cycle and may represent a significant flux of iron and silica waters to the global ocean. Quantifying SGD along the Antarctic margin is complicated by complex subglacial and subsurface hydrogeology and limited observational data. Airborne transient electromagnetic (AEM) surveys have identified extensive high-salinity subsurface brines in the McMurdo Dry Valleys (MDV) that are hydrologically connected to surface features in the MDV (e.g. Taylor Glacier, saline lakes) and are potentially a significant source of SGD to McMurdo Sound. A 2D numerical model was …

Wildlife Ecology And Conservation In A Suburban Preserve Matrix: Applications Of Long-Term Monitoring Data, John Peter Vanek

Graduate Research Theses & Dissertations

Wildlife is important to humans, offering economic, nutritional, ecological, and socio-cultural value. However, vertebrate biodiversity is being lost at rates 100 times greater than the background extinction rate, threatening human livelihood via the loss of ecosystem services. These human-induced species losses are primarily due to habitat destruction, which is increasingly tied to urban development. Conservation of wildlife resources is therefore imperative in a world where more than 50% of the human population, and 80% of people living in the United States, now live in urban areas. In this dissertation, I demonstrate how monitoring data can be applied to answer questions …