Digital Commons Network^™

The Effective Reproduction Number For A Class Of Mixing Matrices In Meta-Population Models In Epidemiology, Gayane Poghotanyan

Open Access Dissertations

Meta-populations models that account for population heterogeneities due to age, gender, spatial location, etc., and incorporate realistic mixing matrices are important for identifying optimal intervention strategies that can mitigate outbreaks of infectious diseases. Problems of finding optimal vaccination strategies for infectious diseases (including measles, mumps and rubella, HIV, and many others) based on such meta-population models are considered in this thesis. The problems are stated in the form of constrained minimization problems for the effective reproduction number, which is a threshold quantity that determines whether or not the disease can spread in the population. One of the most important findings …

Impact Of Changing Climate On Water Resources In The Western Lake Erie Basin Using Swat, Sushant Mehan

Open Access Dissertations

Water quality impairment in the Great Lakes Region has become a major concern for the scientific community. With increasing high intensity short duration precipitation events and rise in temperatures, there is the need to determine the impacts of a changing climate on water resources in the Great Lakes region. This is especially so in the Western Lake Erie Basin (WLEB); Lake Erie is prone to toxic harmful algal blooms due to climate variations and large nutrient and sediment inflows from the surrounding, primarily agricultural lands. The aim of this study was to determine the implications of future climate conditions on …

Quality Control Along Supply Chain, Didun Peng

Open Access Dissertations

Product quality is the core competitiveness of a brand, prompting brand-owner continuously to pursue. Learning curve is the tool to improve product quality by variance reduction. At the same time, knowledge depreciation with its negative effects attracts attention. Thus, a comprehensive learning curve is introduced in this dissertation. This research focus to explore the quality improvement along the supply chain. There are three contributions in this dissertation: 1) it provides the supply chain’s optimal distribution of quality improvement to manufacture and its suppliers; 2) it shows the benefit from coordinated quality improvement among the supply chain; 3) it illustrates the …

Residual Dimension Of Finitely Generated Nilpotent Groups, Mark A. Pengitore

Open Access Dissertations

In previous work, the author claimed an effective characterization for residual finiteness and lower asymptotic bounds for conjugacy separability of all finitely generated nilpotent groups. However, a counterexample to the characterization of residual finiteness for finitely generated nilpotent groups was communicated to the author which also had consequences to the lower asymptotic bound provided for conjugacy separability for the class of finitely generated nilpotent groups. Subsequently, the statements of the asymptotic characterization of residual finiteness and the asymptotic lower bound for conjugacy separability for the same class of groups along with their proofs are incorrect. In this article, we provide …

Cognitive Poetics, Conceptual Metaphors And Blending In German Travel Literature On India, Aditi S. Rayarikar

Open Access Dissertations

In recent years there has been a growth in travel writing and its reception despite the effects of globalization that has brought the world closer than previous centuries. This trend can be further supported with the publication of recent anthologies and theoretical works that explore multi-dimensional approaches to travel writing, especially in the Anglo-American Literature and Cultural Studies.1 But this trend is not just limited to Anglo-American Studies and is equally present in German literature where travel literature also encompasses what is termed as “literature of movement” highlighting migrant literature, transnational and transcultural literature.2 The recently published Reiseliteratur der Moderne …

Imaging And Molecular Analysis Of Murine Dissecting Abdominal Aortic Aneurysms, Evan H. Phillips

Open Access Dissertations

An abdominal aortic aneurysm (AAA) is a localized expansion of the aorta. This disease can sometimes be caused by aortic dissections where the layers of the vessel wall separate, creating a false channel for blood to flow. AAAs are life-threatening because weakening of the vessel wall can lead to aortic rupture and internal bleeding. Unfortunately, most AAAs are associated with no signs or symptoms. Early diagnosis is therefore often not possible and recommendation for life-saving surgery could be delayed. As a result, the mortality rate for patients who experience aortic rupture is up to 90%. Currently we have an incomplete …

Conversion Of Municipal Organic Waste Into Higher Value Acids And Sugars, Raymond M. Redcorn

Open Access Dissertations

Food waste and sewage sludge were studied for their ability to be up-convert to higher value products under three different scenarios; food waste conversion to lactic acid, glycogen quantification in waste activated sludge from municipal wastewater treatment facilities performing enhanced biological phosphorous removal, and finally the conversion of either food waste or sewage sludge to rhamnose biofilm via acid phase digestion.

In studying the conversion of food waste to lactic acid, three factors where opportunities exist for process improvement; freezing of samples during storage, discontinuous pH control, and holdover of fermentation broth between fermentations, were studied. Freezing samples prior to …

Contested “Chineseness” In Transnational Narratives: Works By Post-1979 Chinese/American Immigrant Writers Ha Jin And Geling Yan, Ping Qiu

Open Access Dissertations

This dissertation aims to claim immigrant literature as an essential part of Chinese American studies. It responds to the challenge by considering how “Chineseness” is negotiated, challenged, and transformed in the literary texts produced by both writers. I argue that “Chineseness” as presented by post-1979 immigrant writers Ha Jin and Geling Yan is a transnational process of defamiliarization, radicalization, and transformation. In their work, new immigrant writers are self-consciously and strategically positioning themselves as both insider and outsider. They engage in, negotiate, and challenge the troubling term “Chineseness” as defined in either U.S-centric/Eurocentric or Sinocentric points of view. For writers, …

Diverse Reactivity Of Bimetallic Nickel Imido Complexes Supported By A Redox-Active Ligand, Ian G. Powers

Open Access Dissertations

Imido complexes are a class of organometallic compounds composed of a metal bonded with a divalent nitrogen ligand. Monometallic imido complexes have been shown to engage in a variety of chemical transformations such as two-electron group transfer reactions to form N– heteroatom bonds and can insert into C–H bonds to yield C–H amination products. They have also been demonstrated to undergo single-electron processes such as H-atom abstraction to form amido complexes.

In contrast to monometallic imido species, the chemistry of bimetallic bridging imido complexes is much less understood. Although bridging dinuclear imido complexes have been isolated, the reported reactivity of …

Utilization Of Variable Valve Actuation To Improve Fuel Efficiency And Aftertreatment Thermal Management In Diesel Engines, Aswin Karthik Ramesh

Open Access Dissertations

Fuel consumption in heavy-duty vehicles is expected to double by the year 2050 [1]. The majority of heavy duty vehicles incorporate diesel engines which emit air pollutants including particulate matter (PM), unburnt hydrocarbons (uHC) and oxides of nitrogen (NOx). Increasing demand for heavy duty transportation coupled with strict emission regulations by the Environmental Protection Agency (EPA) and California Air Regulations Board (CARB) to improve air quality drive innovation of advanced engines and auxiliary systems. Complex exhaust aftertreatment (AFT) systems are required to meet stringent tailpipe-out emission regulations. The effectiveness of AFT systems, affected by emission conversion efficiency, is limited when …

Low Temperature Simulations Framework For Quantum Dots And Point Contacts., Harshad Sahasrabudhe

Open Access Dissertations

Quantum computing is becoming increasingly important due to its potential in solving complex optimization problems such as protein folding, and the ability to model correlated electronic systems. Designing of semiconductor based quantum computers is challenging due to the vast number of parameters that need to be optimized from fabrication to their operation. Simulations of these devices could help with the design process. A computational modeling framework is presented that can model quantum point contacts and quantum dots, which are the building blocks of semiconductor based quantum computers. Care was taken to minimize the number of parameters, and use only those …

Exact Methods In Statistical Inference, Yixuan Qiu

Open Access Dissertations

Seeking exact methods for statistical inference problems is a fundamental and central topic in statistics. Exact methods refer to inference procedures that are able to accurately quantify the uncertainty associated with the statistical model for any finite sample size, in contrast to approximate methods that typically rely on largesample asymptotic results. In this dissertation, we investigate three popular models that are widely used in practice but with very few exact inference results, which lead to three parts of this dissertation.

In the first part, we revisit a classical mean comparison model for multivariate data, also known as the multivariate Behrens–Fisher …

Exploring The Role Of Reflexivity In Supporting Preservice Elementary Teachers' Conceptions Of Science As Socially And Culturally Embedded, Jeffrey Radloff

Open Access Dissertations

Achieving widespread scientific literacy has been a longstanding goal of US science standards, requiring that students and teachers possess contemporary nature of science (NOS) conceptions. However, NOS conceptions are repeatedly found to be wide-ranging or ‘naïve’, resulting in regular efforts by science education researchers to hone, or standardize them. While this has improved some aspects of NOS conceptions, others remain relatively unchanged, specifically within prospective, or preservice elementary teacher populations.

One unaffected aspect concerns preservice science teachers’ views of science as socially and culturally embedded, or mutually connected with changes in society and culture. However, understanding this facet of NOS …

Spectral And Directional Control Of Thermal Emission With Nanophotonics, Enas S. Sakr

Open Access Dissertations

Thermal emission is a ubiquitous phenomenon required in many applications, including thermophotovoltaics (TPV), selective solar absorption, and infrared spectroscopy. Making it selective can greatly improve application performance. Here, selectivity is achieved using engineered photonic structures. Two specific design scenarios are discussed for different applications. The first scenario considers angular and spectral selectivity for TPV heat-to-electricity conversion. The second scenario excludes emission towards specific directions, with potential applications in daytime radiative cooling and sensitive IR detectors. In both scenarios, optical modeling is performed using rigorous coupled wave analysis, finite-difference time domain simulations, plus Kirchhoffs law of thermal radiation. In the first …

Online Data Cleaning, Elkindi Rezig

Open Access Dissertations

Data-centric applications have never been more ubiquitous in our lives, e.g., search engines, route navigation and social media. This has brought along a new age where digital data is at the core of many decisions we make as individuals, e.g., looking for the most scenic route to plan a road trip, or as professionals, e.g., analysing customers’ transactions to predict the best time to restock different products. However, the surge in data generation has also led to creating massive amounts of dirty data, i.e., inaccurate or redundant data. Using dirty data to inform business decisions comes with dire consequences, for …

Urban Atmospheric Water Vapor And Its Stable Isotopologues, Olivia E. Salmon

Open Access Dissertations

Water vapor (H2Ov) is known to be a key agent in global scale processes, including: atmospheric circulation, weather, radiative forcing, and energy transfer. Anthropogenic modification of atmospheric H2Ov, and the processes it influences are not as thoroughly studied on the urban or regional scale, in comparison. Airborne measurements made aboard the Purdue University Airborne Laboratory for Atmospheric Research (ALAR) investigated a series of science questions tied to atmospheric H2Ov concentrations in Indianapolis, IN, and the near megacity-sized urban area connecting the Washingon, D.C.-Baltimore, MD area.

The first study described herein focuses on the intermittent urban H2Ov excess signal that was …

Essays On Family And Public Policies, Sophie Danqing Shen

Open Access Dissertations

This dissertation is composed of three independent chapters in the field of family and public policies. The first chapter is a reassessment of the impact of Unilateral Divorce Laws on marriage dissolution. The second chapter studies the effects of a widespread negative incentive policy on teen behavioral and health outcomes. The third chapter studies the impact of post-secondary college education quality on marriage outcomes.

The first chapter evaluates the impact of unilateral divorce laws (UDLs) on the risk of divorce via two distinct channels: the effect on divorce of married couples (divorce effect), and the effect on divorce through initial …

Stochastic Algorithms For Optimization: Devices, Circuits, And Architecture, Yong Shim

Open Access Dissertations

With increasing demands for efficient computing models to solve multiple types of optimization problems, enormous efforts have been devoted to find alternative solutions across the device, circuit and architecture level design space rather than solely relying on traditional computing methods. The computational cost associated with solving optimization problems increases exponentially with the number of variables involved. Moreover, computation based on the traditional von-Neumann architecture follows sequential fetch, decode and execute operations, thereby involving significant energy overhead. To address such difficulties, efficient optimization solvers based on stochastic algorithms were proposed. The stochastic algorithms show fast search time through parallel solution space …

Essays On Structural Econometric Modeling And Machine Learning, Hajime Shimao

Open Access Dissertations

This dissertation is composed of three independent chapters relating the theory and empirical methodology in economics to machine learning and important topics in information age . The first chapter raises an important problem in structural estimation and provide a solution to it by incorporating a culture in machine learning. The second chapter investigates a problem of statistical discrimination in big data era. The third chapter studies the implication of information uncertainty in the security software market.

Structural estimation is a widely used methodology in empirical economics, and a large class of structural econometric models are estimated through the generalized method …

Efficient Neuromorphic Computing Enabled By Spin-Transfer Torque: Devices, Circuits And Systems, Abhronil Sengupta

Open Access Dissertations

Present day computers expend orders of magnitude more computational resources to perform various cognitive and perception related tasks that humans routinely perform everyday. This has recently resulted in a seismic shift in the field of computation where research efforts are being directed to develop a neurocomputer that attempts to mimic the human brain by nanoelectronic components and thereby harness its efficiency in recognition problems. Bridging the gap between neuroscience and nanoelectronics, this thesis demonstrates the encoding of biological neural and synaptic functionalities in the underlying physics of electron spin. Description of various spin-transfer torque mechanisms that can be potentially utilized …

A Quantitative Study Of Faculty Retention And Promotion In Engineering Across Gender, Matilde L. Sanchez-Pena

Open Access Dissertations

The retention and promotion of a diverse engineering faculty body play a primary role in the advancement of the field. Failure to retain engineering faculty has significant economic implications for institutions. Additionally, the availability of role models and potential mentors for women and other minorities is paramount for the continuing diversification of the field. Prior research has documented additional challenges faced by women faculty in engineering when compared to men; such evidence has resulted in significant attempts to attenuate such disparities among faculty at all ranks. From the institutional perspective, examining retention and promotion times across gender would help to …

Regulation Of Thermogenic And Inflammatory Response In Adipose Tissue By 18-C Fatty Acids, Sunhyue Shin

Open Access Dissertations

Dietary fatty acids, in particular long-chain fatty acids (LCFA), are involved in the regulation of metabolic, oxidative, and inflammatory responses. This is a mechanism by which fatty acids participate in the regulation of energy homeostasis and impact development of obesity, type 2 diabetes, and cardiovascular diseases. White and brown adipose tissue play a significant role in energy storage and expenditure through fatty acid uptake and oxidation. LCFA, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been reported to induce thermogenesis by activating brown and beige adipocytes to oxidize more fuel molecules. However, the effects of 18-carbon (18-C) LCFA with …

Novel Tools To Study Modulation Of Adenylyl Cyclase Isoforms, Monica Soto-Velasquez

Open Access Dissertations

Adenylyl cyclases (AC) are a major component of the cAMP signaling pathway. The differential regulatory properties and tissue expression patterns of the nine transmembrane AC isoforms provide unique mechanisms to regulate cAMP signaling in a precise and organized manner. However, the understanding of the individual roles of AC isoforms in the overall cellular response presents considerable challenges due to the expression of multiple AC isoforms in cells, and the lack of available tools to accurately detect isoform-specific AC expression or selectively modulate its catalytic activity. For these reasons, the research aims of this study were to develop a series of …

Spectroscopy Of Ultracold Lithium-Rubidium Molecules, Ian Stevenson

Open Access Dissertations

I present spectroscopic data on ultracold lithium-rubidium molecules in a dual species magneto-optical-trap in order to find suitable intermediate states to transfer population to the rotational, vibrational and electronic ground state via a stimulated Raman process. First, I improved the accuracy of the energetic location of the ground state by two orders of magnitude using photoassociation as a spectroscopic tool to measure the energy of bound states relative to the scattering continuum. Second, we studied the d 3Π-D 1Π and A 1Σ+ -b 3Π0+ excited electronic manifolds with a combination of resonantly-enhancedmulti-photon-ionization and depletion spectroscopy finding suitable singlet-triplet mixed states …

Iii-V And 2d Devices: From Mosfets To Steep-Slope Transistors, Mengwei Si

Open Access Dissertations

With silicon CMOS technology approaching the scaling limit, alternating channel materials and novel device structures have been extensively studied and attracted a lot of attention in solid-state device research. In this dissertation, solid-state electron devices for post-Si CMOS applications are explored including both new materials such as III-V and 2D materials and new device structures such as tunneling field-effect transistors and negative capacitance field-effect transistors. Multiple critical challenges in applying such new materials and new device structures are addressed and the key achievements in this dissertation are summarized as follows: 1) Development of fabrication process technology for ultra-scaled planar and …

Regulation Of The Endogenous Antioxidant Defense System In Diabetic Peripheral Neuropathy, Mateusz A. Stochelski

Open Access Dissertations

Oxidative stress is implicated as a major contributor to the development of diabetes induced peripheral neuropathy. This debilitating condition significantly impacts the quality of life of patients, yet available treatment options are not optimal. They include tricyclic antidepressants, anticonvulsants, serotonin-norepinephrine reuptake inhibitors, selective serotonin reuptake inhibitors, and opiates. Unfortunately, these treatment options only reduce pain by 30-50%, and many patients discontinue use due to side effects. Furthermore, the current treatment options are focused on pain reduction, but not the protection of the peripheral nerves. Since oxidative stress driven by high glucose concentrations has been implicated as the key factor causing …

A Study Of Techniques And Mechanisms Of Vagus Nerve Stimulation For Treatment Of Inflammation, Jesse P. Somann

Open Access Dissertations

Vagus nerve stimulation (VNS) has been on the forefront of inflammatory disorder research for the better part of the last three decades and has yielded many promising results. There remains, however, much debate about the actual biological mechanisms of such treatments, as well as, questions about inconsistencies in methods used in many research efforts.

In this work, I identify shortcomings in past VNS methods and submit new developments and findings that can progress the research community towards more selective and relevant VNS research and treatments. In Aim 1, I present the most recent advancements in the capabilities of our fully …

Electrophysiological And Spatial Orientation Ability Differences In Expert And Novice Aircraft Pilots, Karthik Sukumar

Open Access Dissertations

Exploring differences between experts and novices by observing task-specific performance has been an important area of research in several domains. This study examined differences in expert and novice aircraft pilots based on their cortical activity and spatial orientation ability. Twenty-eight aircraft pilots (eight experts, 20 novices) performed 23 in-flight sequences inside a flight simulator while their cortical activity was recorded using an electroencephalographic (EEG) device. Thirty-two aircraft pilots (11 experts, 21 novices) attempted a 30-question multiple-choice spatial orientation ability test. Outcomes of the study revealed significant differences in cortical activity between expert and novice groups. Novice pilots projected higher mental …

Search For Electrophysiological Indices Of Hidden Hearing Loss, Chandan H. Suresh

Open Access Dissertations

Recent studies in animals indicate that even moderate levels of exposure to noise can damage synaptic ribbons between the inner hair cells and auditory nerve fibers without affecting audiometric thresholds, giving rise to the use of the term “hidden hearing loss” (HHL). Given the pervasive exposure to occupational and recreational noise in the general population, it is likely that individuals afflicted with HHL will go unidentified unless sensitive clinical measures are developed to diagnose this condition. To date, the studies employed to characterize HHL in humans have yielded equivocal results - some studies show wave I amplitude decrement while others …

Design And Characterization Of Optical Fiber-To-Chip Edge Couplers And On-Chip Mode Division Multiplexing Devices, Min Teng

Open Access Dissertations

Integrated silicon photonics has recently emerged as a promising solution to data interconnection in large data centers, which are characterized by short-range (0.5 – 2 km) and high bandwidth, i.e. 400 Giga-bit-per-second. Light from an external laser is first coupled to a silicon photonic chip, splits and modulated to carry data, and then multiplexed and coupled out to one or more optical fibers to take advantage of their large data bandwidth over their electric counterparts. However, short-range optical communication is still faced with several technical challenges. First, the difficulty to couple light between optical fibers and chips leads directly to …