Digital Commons Network^™

Analysis Of Metallic Shielding For Reduction Of Rf Induced Heating Of Electrode During Mri For Active Implants, Krishna M. Singhal

Open Access Dissertations

The options available to patients with implantable devices are limited. It is because there are multiple interactions between the MRI environment and the implantable medical devices. The three main components of MRI systems- static magnet, RF coil, and a gradient coil- interact with the implantable medical devices. These interactions can cause force, torque, device vibrations and RF-induced heating. Among all these potential hazards is the heating caused by the RF electromagnetic field. The lead wires of the implants can act as antennas and pick up the electric field generated by the RF coil. This results in the induced current traveling …

Village In The City: Collective Efficacy And Neighborhood Stability On Chicago’S Far Southwest Side, Joy L. Kadowaki

Open Access Dissertations

The theory of collective efficacy highlights the importance of community members’ shared expectations for social control and their trust and cohesion with one another for predicting neighborhood variation in crime and other social outcomes. Researchers have found that neighborhood collective efficacy is largely stable over time and predicts future variation in crime and other social outcomes, independently of neighborhood social composition. An expansive body of quantitative research has made a very compelling case for the durability of collective efficacy as an important neighborhood process, but a number of questions remain regarding the social mechanisms by which it operates. This dissertation …

Genotype By Nitrogen Management Investigations Into Mitigating Stress And Soil Nitrogen Depletion In African Continuous Maize Production, Heather Randolph Pasley

Open Access Dissertations

Adoption of maize (Zea mays L.) hybrids with enhanced drought/heat/low N stress tolerance and increasing the application of N fertilizer have both been proposed as potential solutions for Subsaharan Africa (SSA)’s food insecurity. Neither solution, however, has been able to increase grain yield in SSA at the same rate seen in other parts of the world as drought/heat/low N stress are often not the only yield-limiting factors in SSA. The primary objectives of this study were to determine what stresses are limiting grain yield response to N fertilizer, to evaluate differences among hybrids in terms of their relative stress tolerance …

A Model Based Iterative Reconstruction Approach To Tunable Diode Laser Absorption Tomography, Zeeshan Nadir

Open Access Dissertations

Tunable diode laser absorption tomography (TDLAT) has emerged as a popular nonintrusive technique for simultaneous sensing of gas concentration and temperature. The gas concentration and temperature is computed by making light absorbance measurements using tunable diode lasers. Major challenges of TDLAT imaging include a highly nonlinear measurement process and availability of only a few light absorbance measurements. Therefore, TDLAT imaging of concentration and temperature is an ill-posed, nonlinear inverse problem. Conventional approaches to TDLAT primarily consist of making restrictive assumptions about the gas flow to simplify the problem.

In this thesis, we study the problem of reconstruction of TDLAT measurements …

Proton Doping And Characterization Of Rare Earth Nickelates, Derek Karl Wittenburg Schwanz

Open Access Dissertations

Perovskite rare earth nickelates with formula RNiO3 (R = trivalent rare earth element) feature exceptional electrical behavior and performance in a wide variety of functional applications due to their unique metal-insulator transition. This distinctive phase transition is caused by charge disproportionation as the crystal structure distorts upon temperature change and electron-electron interactions result in a modified band structure. However, electron doping of the same nickelate systems has created a more pronounced phase transition wherein unprecedented resistivity changes on the order of 1010 Ω*cm are achieved through the opening of a wide bandgap. In this work, a new method for inducing …

Electronics And Optoelectronics Devices From Low-Dimensional Systems, Yuqi Zhu

Open Access Dissertations

The notion of low dimensionality becomes more than a pure mathematical ideal, as scaling of modern electronics reaches a state of the art in which electrons are strongly confined at the interface between silicon and the gate oxides in MOSFETs. Moreover, the improvement of material synthesis in the last two decades gives rise to many fascinating materials, in which the electronic states are confined at least for one dimension, like quantum dots (QD) for 0 dimension (0D), carbon nanotubes (CNT) for 1 dimension (1D), graphene and transitional metal dichalcogenides (TMD) as 2 dimensions (2D). In these materials, quantum confinement due …

Towards Predictor Adaptive Robust Control And Inference Of Cyber-Physical Systems With Applications To Aerospace Systems, Jayaprakash “Suraj” Nandiganahalli

Open Access Dissertations

The simultaneous presence of factors such as uncertain plant parameters (e.g., inertia variations, change of damping coefficient), time-varying disturbances (e.g., imprecise mathematical models, uncertain nonlinearities), input delay (e.g., due to transport phenomenon, computation latencies, communication lags), and inaccessibility of the plant states of an nth− order dynamical system present a challenge to the formal control design and to its closed loop stability and performance guarantees. It is well-known that input delays can cause negative phase shifts, limiting the control bandwidth which when coupled with system uncertainties can potentially shift the system into an unstable region of operation. This is especially …

Quantifying The Relations Among Neurophysiological Responses, Dimensional Psychopathology, And Personality Traits., Takakuni Suzuki

Open Access Dissertations

The Research Domain Criteria (RDoC) model, one of the transdiagnostic dimensional models of psychopathology proposed by the National Institute of Mental Health, emphasizes the integration of basic biological science into clinical research. The event-related negativity (ERN), a deflection in electroencephalogram after making an error, is a promising neurophysiological indicator for such endeavor. However, RDoC model posits that ERN is related to three of the five broad dimensions without any indication of how ERN relates differently across the dimensions. Recent research indicate that ERNs elicited from different tasks do not elicit the exact same ERNs. Therefore, constructing theoretically guided tasks and …

Quantum Transport In Threedimensional Topological Insulators, Yang Xu

Open Access Dissertations

In this thesis, I will describe our electrical transport approach in studying three-dimensional topological insulators (3D TIs). A 3D TI is a quantum material characterized by a gapped bulk and gapless surface states that are topologically protected by time reversal symmetry, thus immune to backscattering. It provides an excellent platform to pursue a plethora of exotic physics and novel device applications such as spintronics. However, in most of the prototypical 3D TIs (like Bi2Se3, Bi2Te3, and Sb2Te3), the bulk carriers always unavoidably present and overwhelm the surface conduction in transport measurements.

Here, taking advantage of material engineering, we have successfully …

Pre-Service Teachers' Understanding Of Geometric Reflections In Terms Of Motion And Mapping View, Murat Akarsu

Open Access Dissertations

In this manuscript, I describe a study of pre-service secondary mathematics teachers’ (PTs) understanding of geometric reflection in terms of a motion and a mapping views. PTs often have a motion view of geometric reflection based on their understanding of reflection line, domain, and plane. A motion view is a preliminary perspective developed prior to the construction of a mapping view. PTs need a mapping view of geometric reflection, and to be conscious of sub-concepts of a mapping view involved reflection line, domain, and plane. However, there is no clear evidence documenting how a learner’s motion view evolves to produce …

She Is A Computer Scientist: A Quantitative Comparison Between The Effectiveness Of Game Design Studios And Robotics At Enhancing Women's Learning Of, Self-Efficacy In, Attitudes Toward, And Domain Identification With Computer Science, Ali Nazil Alshammari

Open Access Dissertations

The underrepresentation of women in computer science is a serious issue with ramifications that affect not only women working in the field, but also the field at large and the national economy. While the problem is attributed to several interconnected causes, such as computer knowledge, experience, and familiarity; they do not tell the entire story, nor do they point to a global trend. Studies indicate that these factors did not stop the computer science field from achieving a balanced male-female ratio in non-western countries. Since no single factor can be attributed as the primary cause of this complicated problem, and …

Comparison Of Brachypodium And Wheat Response To Hessian Fly, Abdelrahman Ahmed Abdelhady Mohamed Awad

Open Access Dissertations

Wheat (Triticum aestivum) yield is limited by biotic stresses such as Hessian fly [Mayetiola destructor (Say)] attack which causes a significant annual loss. Previous studies have shown that Brachypodium distachyon is resistant to Hessian fly infestation. Since B. distachyon has advantages over wheat to be used as a model plant in genetic and genomics, we compared the response of 5 wheat lines (4 resistant lines, harboring different Hessian fly-resistance H genes, and 1 susceptible line to Hessian fly infestation) to B. distachyon at early stages [12 hours, 1 day, 3 days and 5 Days After Hessian fly egg-Hatch (DAH)] of …

Interparental Conflict As A Context For Early Child-Parent Attachment Relationships, Laura Yanett Anaya

Open Access Dissertations

The present study explored the concurrent relations between interparental conflict strategies and early child-parent attachment relationships, while considering potential mediating (i.e., parental sensitivity) and moderating (i.e., involvement of child in conflict) variables in the relations. A nonclinical sample of mostly non-Hispanic Caucasian triads (i.e., mother, father, child) were recruited. Parental sensitivity and children's attachment security were observed across four visits: one visit was in the home with mother, one visit was in the home with father, one visit was in the park with mother, and one visit was in the park with father. In a fifth visit, in the research …

An Overall Policy Decision-Support System For Educational Facilities Management: An Agent-Based Approach, Haya Bader Albader

Open Access Dissertations

Although K-12 public school facilities infrastructure investments are second only to highways, schools continue to suffer from an approximately $38 billion annual funding gap. Massive reductions in funding are forcing school districts to make tough decisions to optimize maintenance expenditures. Over the last three decades, a huge body of research has determined that the condition of school facilities do affect student health and performance, and some have further demonstrated that schools are overwhelmed by deteriorating facilities that threaten the health, safety, and learning opportunities of students. The currently available educational facility management approaches oversee the influence of the complex and …

Data-Driven Resource Allocation In Virtualized Environments, Lianjie Cao

Open Access Dissertations

Modern advances in virtualization technologies have revolutionized the way we build and manage computer systems. Virtualization technologies, however, adversely impact the predictability of system performance. This introduces several challenges in balancing performance and resource utilization.

In this dissertation, we explore and address performance challenges introduced by virtualization in two application scenarios: network functions virtualization and distributed network emulation.

First, we investigate the performance of virtualized network functions (VNFs) and propose a framework, NFV-VITAL, that characterizes performance impacts of hardware and software options and determines the optimal configuration for initial deployment of a VNF. Then we propose a system, Elastic resource …

A Framework For Comparative Life-Cycle Evaluation Of Alternative Pavement Types, Saeed Alqadhi

Open Access Dissertations

Researchers and practitioners agree that the selection of an appropriate pavement surface material type should be made based on a comprehensive evaluation that incorporates the costs and benefits associated with each alternative for the stakeholder. The most appropriate material type generally is the most cost-effective alternative over the pavement life cycle. Hypothetically, the most appropriate material type will vary across the various geographical regions of the U.S. because material costs and performance are influenced by the deterioration agents at play and the construction costs in a region. To address this issue, this dissertation proposes a comprehensive methodology to identify the …

‘Makingthings Happen’ In Cross-Sector Partnerships: A Multiple Case Study, Priyanka Shah Brunese

Open Access Dissertations

Cross-sector collaborative partnerships aim to bring resources and knowledge from their particular sectors to provide innovative solutions in response to current social, economic and environmental problems, and for developing policies and processes for emergent issues. However, cross-sector partnerships involving public (i.e., institutions of higher education), private, and nonprofit organizations are complex and dynamic systems that are extremely difficult to manage once they have been established. Organizations spanning different sectors not only have dissimilar operating models, working cultures, values, and leadership styles, but are driven by different motives in joining the partnership thereby making the act of collaborating very challenging. When …

Assessment Of Urbanization Impacts On Surface Runoff And Effects Of Green Infrastructure On Hydrology And Water Quality, Jingqiu Chen

Open Access Dissertations

Urbanization is one of the most important anthropogenic modifications of the global environment. It has significant impacts on hydrologic processes and water quantity and quality. Research related to urbanization impacts on surface runoff has focused on changes up to the watershed scale. However, quantitative assessment at a national scale is scarce. Parallel to urbanization impacts, climate is also one of the greatest challenges facing humanity today and its effects are already being felt from strengthened storms and rising sea levels to changing temperature and weather patterns. The adverse impacts of urbanization and climate can converge in synergistic ways, which may …

The Human Dimensions Of Invasive Plant Management On Family Forestlands: A Case Study In Indiana, Mysha K. Clarke

Open Access Dissertations

Invasive plant management is an increasing concern in socio-ecological systems. Ecologically, invasive plants can displace native species, reduce forest health and productivity, and degrade recreational areas. From a socio-economic perspective, the United States spend approximately USD 137 annually in damage and control costs from invasive plants and animals. Despite these impacts, invasive plants continue to spread in forest ecosystems because of various anthropogenic factors like trade, transportation, climate change, and limited regulation in many states. It is pivotal to consider the role of family forest owners (FFOs) in invasive plant management in forest ecosystems because collectively they own 36% of …

Modeling And Simulation Of Blood Flow Past The Distal Anastomosis Of The Arteriovenous Graft For Hemodialysis, Zengding Bai

Open Access Dissertations

Hemodialysis is a common treatment for ESRD patients to manage their chronic renal failure while awaiting kidney transplant. Arteriovenous graft is a major vascular access for hemodialysis but often fails due to the thrombosis close to the anastomosis. Most of existing computational models employ an unrealistic rigid model assuming the vein and graft are rigid. And some of the existing results are inconsistent in characterizing the flow and force fields. We introduce a new three-dimensional computational model that incorporates the vein and graft deformability. The new model is based on the lattice Boltzmann-immersed boundary (LB-IB) framework for handling the fluid-flexible-structure …

Secular Discourse In Postcolonial West African Narratives: Problems And Perspectives: A Comparative Study, Malick Coly

Open Access Dissertations

The making of modern African nations and their attendant secularistic establishment have not only altered traditional socio-political structures, this shift has equally affected the relations between individuals as well as communities. In the process leading to modern sociocultural transformations, tensions and discourse have arisen. Toyin Falola’s Violence in Nigeria: Crisis of Religious Politics and Secular Ideologies, and Ousman Murzik Kobo’s Unveiling Modernity in Twentieth-Century West African Islamic Reforms highlight respectively the political and religious divide in post-Independence Nigeria and the impact of Islamic reform in Ghana and Burkina Faso. These two historical studies show the complexity of modern West African …

Label Free Chemical Imaging Reveals Novel Metabolite Signatures In Living Model Organisms, Jing (Andy) Chen

Open Access Dissertations

Cell and molecular biology often need direct monitoring of the dynamic distribution and interactions of metabolites in living cells and model organisms. However, this task is extremely challenging for a few reasons. Labeling metabolites with markers can potentially interrupt the dynamic cellular events that are aimed to be observed. Moreover, labeling dyes are usually toxic to cells. Lastly, many labeling methods require cell fixation thus cannot be used to study cellular dynamics. Label-free chemical imaging methods such as stimulated Raman scattering (SRS) circumvent these problems by generating signals based on the intrinsic optical property of target biological metabolites. As a …

Computational Methods For Matrix/Tensor Factorization And Deep Learning Image Denoising, Joon Hee Choi

Open Access Dissertations

Feature learning is a technique to automatically extract features from raw data. It is widely used in areas such as computer vision, image processing, data mining and natural language processing. In this thesis, we are interested in the computational aspects of feature learning. We focus on rank matrix and tensor factorization and deep neural network models for image denoising.

With respect to matrix and tensor factorization, we first present a technique to speed up alternating least squares (ALS) and gradient descent (GD) − two commonly used strategies for tensor factorization. We introduce an efficient, scalable and distributed algorithm that addresses …

Hispanic Acculturation And Perceived Discrimination's Impact On Emerging Adult's Internalizing And Externalizing Symptoms Over Time: A Longitudinal Investigation., Hector F. De Los Santos

Open Access Dissertations

Perceived discrimination and acculturation are key minority status and cultural variables that impact Hispanic mental health. Despite discrimination being a chronic stressor and acculturation being a developmental process, the impact of these experiences have been primarily investigated cross-sectionally. This paper uses longitudinal analyses to explore how perceived discrimination and acculturation impact growth internalizing and externalizing symptoms over time, adding nuance to previous literature. Using the Pathways to Desistance Mexican American sample (N =332), this paper utilized latent growth curve analyses to evaluate acculturative theories on mental health and the immediate and longitudinal impact of discrimination on a broad spectrum of …

Conventions Of The Commons: Technical Communication And Crowdsourced Digital Publishing, Amelia Chesley

Open Access Dissertations

This project traces the digital publishing history of the audiobook archive LibriVox.org, examining how its volunteers manage, control, and negotiate procedures and policies for their ongoing collaborative work. Examples of public knowledge work like LibriVox illustrate the value of professional and technical communication in accessibly digitizing knowledge and culture for use now and in the future. I investigate and theorize how groups of diverse and transient volunteers create and engage with the tools and documentation they use to manage their crowdsourced audio digitization work. The example of LibriVox can help us better recognize and value the invitational care work embedded …

"Do I Even Remember The List?': Identity, Place, And Legal Consciousness Of Marriage Among Lgbtq Individuals.", D Ross Beall

Open Access Dissertations

The legalization of same-sex marriage in 2015 in the United States has been a milestone for LGBTQ rights. Popular campaigns pushing for the legalization argued that “love is love” and the idea that same-sex marriage is the same as heterosexual marriage. While there have been surveys investigating popular opinions around same-sex marriage, not much research has been done on LGBTQ communities themselves and what they have to say about marriage. This dissertation obtains a clearer understanding of how LGBTQ individuals consider marriage at a critical moment in history. Specifically, this dissertation investigates how identity, place, and legal consciousness interact within …

Metaethical Mooreanism, Jonathan Fuqua

Open Access Dissertations

This dissertation is an attempt to apply the Moorean response to radical skepticism to moral skepticism. In a nutshell, I argue as follows. Assume that the following Moorean response to, say, BIV skepticism (the worry that I don’t know I’m not a brain in a vat) is roughly correct: “I know I have hands, so I’m not a BIV; any argument to the contrary must have a flaw somewhere.” If so, then such a Moorean should respond as follows to moral skepticism: “I know that recreational genocide is wrong, so it’s false that there are no moral facts, and that …

Design And Development Of Adaptive Intrusion Management For Cyber-Based Systems, Muhamad Felemban

Open Access Dissertations

With the growing Cyber-security threats to governmental and organizational infrastructures, the need to develop high resilient Cyber-Based Systems (CBSs) that preserve the security of data is becoming increasingly important. A prominent type of Cyber-attacks is intrusion attacks that aim at data tampering, which can impair the confidentiality and the integrity of data. Therefore, it is imperative to design a holistic intrusion management approach for CBSs.

In this dissertation, we address the challenges of designing and developing a resilient intrusion management system. In particular, we propose an adaptive data Partitioning-based Intrusion Management System (PIMS) that can endure intense malicious intrusion attacks …

Acute Effects Of Contractile Activity On Skeletal Muscle Exosomes, Ron T. Garner

Open Access Dissertations

Introduction: Skeletal muscle functions as an endocrine organ, and a key way to accomplish that is through exosomes. The internal budding of a multivesicular body (MVB) forms exosomes and contains mRNA, miRNA, and proteins. Through a multifaceted approach, the following three experiments were designed to better understand the effect of contractile activity on skeletal muscle MVB/exosome biogenesis and release.

Study 1: Exosome-related pathway response to acute exercise. Sedentary, lean, healthy male subjects (n=12) performed 45 min cycling (AEx), followed by single leg knee extensor exercise (A+REx). A biopsy was obtained prior to exercise and 1 hr post-exercise from each leg. …

Polysulfide Mitigation At The Electrode-Electrolyte Interface: Experiments In Rechargeable Lithium Sulfur Batteries, Arthur D. Dysart

Open Access Dissertations

In the field of energy storage technology, the lithium sulfur battery is intensely studied in interest of its great theoretical gravimetric capacity (1672 Ah kg–1) and gravimetric density (2600 Wh kg–1). The theoretical performance values satisfy viability thresholds for petroleum–free electric vehicles and other emerging technologies. However, this elusive technology remains in the research sector due to a wealth of challenges resulting from its complex chalcogenide electrochemistry. The most infamous challenge remains the polysulfide redox shuttle, a phenomenon in which lithium polysulfide intermediates are produced as elemental sulfur S8 is reduced to lithium sulfide Li2S during the discharge cycle. Because …