Digital Commons Network^™

A Fuzzy Clustering Methodology To Analyze Interfaces And Assess Integration Risks In Large-Scale Systems, Josh Henry Goldschmid

Doctoral Dissertations

“Interface analysis and integration risk assessment for a large-scale, complex system is a difficult systems engineering task, but critical to the success of engineering systems with extraordinary capabilities. When dealing with large-scale systems there is little time for data gathering and often the analysis can be overwhelmed by unknowns and sometimes important factors are not measurable because of the complexities of the interconnections within the system. This research examines the significance of interface analysis and management, identifies weaknesses in literature on risk assessment for a complex system, and exploits the benefits of soft computing approaches in the interface analysis in …

Enhanced Heavy Oil Recovery By Low Salinity Polymer Flood Combined With Microgel Treatment, Yang Zhao

Doctoral Dissertations

“Heavy oil resources account for a large portion of the total oil reserves around the world. The target heavy oil reservoir is located on Alaska’s North Slope (ANS). Advantages of low-salinity HPAM polymer (LSP) over high-salinity polymer (HSP) were demonstrated. LSP could recover more oil with 40% less polymer consumption. No additional oil was recovered by HSP after LSP flood. The first-ever polymer flood pilot on ANS showed remarkable success regarding water cut reduction, oil production increase, delayed breakthrough, and projected oil recovery improvement. Polymer alone was insufficient to achieve satisfactory recovery as the reservoirs were highly heterogeneous. Microgels could …

Multimodal Neuroscience Data Modeling And Inference, Sima Azizi

Doctoral Dissertations

“Mathematical models can be combined with deep learning and machine learning methods to provide new insights in neuroscience. The field of neuroscience is characterized by rich datasets that include fluid biomarkers, EEG signals, and advanced neuroimages. Recent advances in natural language processing have led to the opportunity to gain additional insights from rapidly growing text databases as well as electronic health records. In this research, we focus on applying computational intelligence methods to the analysis of three different complex data sources: blood levels of disease biomarkers, EEG signals from schizophrenic patients, and disease phenotypes encoded in electronic health records. First, …

Relating Detonation Parameters To The Detonation Synthesis Of Nanomaterials, Martin Langenderfer

Doctoral Dissertations

“This research investigates the physical and chemical processes that contribute to the detonation synthesis of silicon carbide nanoparticles. Bulk production of SiC nanoparticles through detonation is possible due to pressures achieved over 20 GPa and temperatures over 2000 K as well as quenching rates in excess of 13 billion K/second. These conditions catalyze reaction and bottom-up molecular growth while retaining particles < 100 nm in diameter. In this work, detonation synthesis of SiC was demonstrated by incorporation of polycarbosilane, an SiC precursor material, into an RDX/TNT explosive matrix prior to detonation. Detonation Synthesis of SiC was also accomplished by reacting elemental silicon with carbon liberated by the detonation of negatively oxygen balanced TNT. Hydrodynamic simulation of a 60:40 mass ratio RDX/TNT detonation created conditions thermodynamically suitable to produce cubic silicon carbide within the first 500 nanoseconds after the passage of the detonation wave while carbon remains chemically reactive for molecular formation. Simulations and experimental tests indicated that loading configuration and impedance mismatch of the precursor additives used in detonation synthesis results in conditions in the additives that exceed the accepted detonation pressure of the explosive by greater than three times. Finally, a full factorial experimental design showed increasing silicon concentration, reducing silicon size, and reducing oxygen balance by adjusting the ratio of RDX to TNT decreased the explosives detonation pressure by 20% and increased the soot yield and concentration of SiC observed in the detonation products by 82% and 442% respectively”--Abstract, page iv.

Experimental And Numerical Studies Of Novel Thermal Energy Storage Materials For Applications In Concrete And Energy Storage Systems, Wenyu Liao

Doctoral Dissertations

In this work, several types of novel thermal energy storage (TES) materials and composites are explored, and a series of numerical simulation models and experimental protocols are developed to evaluate the potentials of these materials to be applied in concrete, pavement, and thermal energy storage systems.

The first two types of novel TES materials/composites are at the micro-scale, which use micro diatomite (DE) and cenosphere (Ceno) as carriers of phase change material (PCM), respectively. The third type of novel TES material is at the macro-scale, utilizing lightweight sand (LWS) and lightweight coarse aggregate as carriers to load PCM. The last …

A Meta-Analysis Of Gender Gap On The Fci In High School And College Introductory Physics Courses In The Us And International Countries., Polin Yadak

Doctoral Dissertations

This meta-analysis synthesized research on gender gap in the Force Concept Inventory (FCI). The main goal of the present meta-analysis was to identify the moderator variables that mediate effect size differences. Furthermore, the statistical significance of the average effect sizes was investigated. The inclusion criteria for the meta-analysis resulted in 22 empirical research articles that studied gender gap and reported the number of male and female students in the study. The included articles reported multiple studies; therefore, there were 34 studies on pretest and 43 studies on the posttest FCI. The average effect size for the pretests was 0.62 and …

Examining The Overlooked Complexities Of School Lunch: An Investigation Into The Juncture Of Food, Schooling, And The Developing Adolescent, Eleanor Kane

Doctoral Dissertations

School lunch is a universal experience for students everywhere and yet remains largely understudied by educational researchers. This dissertation explores school lunch through the lens of adolescent identity theory, with the purpose of investigating the unarticulated and overlooked complexities inherent in the lunch block, from issues of the developing sense of self, to social and cultural meanings surrounding food, and consequences for social reproduction. I used a combination of ethnographic observations and narrative interviews at a rural New England high school, focusing on participants’ daily habits, food practices, and choices during the lunch block. Through this, I established the normative …

Utilizing Extended Continental Shelf (Ecs) And Ocean Exploration Mapping Data For Standardized Marine Ecological Classification Of The U.S. Atlantic Margin, Derek C. Sowers

Doctoral Dissertations

Accurate maps of ocean bathymetry and seafloor habitats are needed to support effective marine ecosystem-based management (EBM) approaches. The central premise of this thesis was to synthesize geomorphological elements of large regions of the deep ocean seafloor to establish standards of characterization for ecosystem-based classification. The approach was to apply semi-automated characterization techniques on seafloor bathymetric data that were originally collected for other purposes. The purpose of generating these maps is ultimately to apply to informing ecosystem-based management for large marine regions. While seafloor classification techniques for habitat classification have been applied in shallow water and generally over more local …

White Discipline, Black Rebellion: A History Of American Race Riots From Emancipation To The War On Drugs, Jordan C. Burke

Doctoral Dissertations

This dissertation is a comparative analysis of American race riots, within and across historical eras, from Emancipation (1863) to the War on Drugs (1972). I argue that changes in the status of African-American citizenship produced different forms of race rioting. Examining riot events across eras reveals how ethical principles at the core of democracy are undermined in specific socio-historical contexts—especially equality of participation in collective self-governance. Congressional testimony, state-sponsored riot investigations, and archival data indicate that riots have been used historically to structure racial inequality in both political institutions and economic relations. While race riots have proven instrumental in maintaining …

Data Analysis For A Balloon Borne Compton Polarimeter, Sambid Kumar Wasti

Doctoral Dissertations

The Gamma RAy Polarimeter Experiment (GRAPE), a balloon borne Compton polarimeter for 50-500 keV gamma rays, was successfully flown for the second time in 2014. GRAPE uses events in which a photon scatters between 2 detector elements to measure the polarization of the measured photons. GRAPE consists of 24 collimated polarimeter modules. Each module is made up of 64 rectangular scintillators elements in a grid of 8 × 8 (36 plastic scintillators surrounded by 28 CsI scintillators). GRAPE was flown from Fort Sumner, New Mexico on the morning of September 26th 2014. The experiment was at float altitude for 14.4 …

Bacterial Genome And Population Dynamics With Implications For Public Health, Cooper John Park

Doctoral Dissertations

Bacterial populations are extraordinarily heterogeneous. Despite growing clonally, these populations are often composed of multiple lineages distinguished by both phenotypic and genetic differences that are caused by both allelic and whole gene variation. Such genomic mosaicism and within-species variation can significantly impact a species’ response to selective pressures from antibiotic use, vaccination, immune responses and host environment. One important process that contributes to this phenomenon is recombination, the exchange of very similar DNA sequences between strains which can result to either the addition or replacement of homologous genes. Current models of microbial recombination incorporate the null expectation that recombination is …

Magnetoelastic Excitations In Chiral Magnets, Christopher Libby

Doctoral Dissertations

Emergence of quasiparticles is a central concept in condensed matter physics. As an example, in solids, lattice vibrations lead to quantized phonon excitations, which gives rise to many exotic phenomena, including superconductivity. Things become richer in magnetic systems. Collective fluctuations about a magnetic ground state induce the spin wave excitation, whose quantized quasiparticle is dubbed as the magnon. A fundamental question is how phonon and magnon, as two separate degrees of freedom, can be coupled together. More importantly, certain symmetry, such as spatial inversion symmetry, can be broken in novel magnetic textures. It is interesting to explore whether broken symmetry …

Search For An A' Resonance In The Heavy Photon Search 2.3 Gev Data Set, Samantha Katherine Mccarty

Doctoral Dissertations

The Heavy Photon Search (HPS) experiment is based out of the Thomas Jefferson National Accelerator Laboratory in Newport News and is designed to test the potential existence of a new particle, the "heavy photon" or "A'," which has the potential to mediate interactions between dark forces and the Standard Model. HPS is designed to detect the decay of an A' particle into e⁺e⁻ pairs utilizing an electromagnetic calorimeter and a silicon-strip tracking detector. If the theory is correct, the A' could be generated using the Jefferson Lab high-luminosity electron beam incident upon a tungsten target.

In 2016, HPS collected 10.6 …

Uncovering Examples Of Humanizing Praxis And Pathological Violence In Special Education: District, Parent, And Researcher Perspectives, Andy W. Chung

Doctoral Dissertations

Students of color continue to be labeled with dis/abilities and funneled into segregated settings by special education staff (Annamma, Connor, & Ferri, 2013; Leonardo & Broderick, 2011). The purpose of this study is to highlight the kinds of experiences students and their family’s experience in special education related to humanization and violence. In addition to gaining a better understanding of how special education district staff are working to both reproduce and disrupt the violent exclusion of students of color, this dissertation aimed to center the experiences of parents and students who are being impacted by the exclusionary policies and practices. …

Stochastic Decision Modeling To Improve Breast Cancer Preventive Care, Sevda Molani

Doctoral Dissertations

Breast cancer is a leading cause of premature mortality among women in the United States. Breast cancer screening tests can help with detecting breast cancer in early stages and thereby reducing the breast cancer mortality risk. However, due to the imperfect nature of screening tests, there is always some associated overdiagnosis, false positives, and false negatives risks. Therefore, to improve breast cancer preventive care, we defined the focus of this dissertation on modeling breast cancer screening decisions.

Breast cancer overdiagnosis is the first issue that is addressed in this dissertation. Although overdiagnosis is known to be the major risk inherent …

The Influence Of Online Product Recommendations On Consumer Choice-Making Confidence, Effort, And Satisfaction, Mohammad Amin Saleh

Doctoral Dissertations

The number of products and services available online is growing at a tremendous pace. Consumers increasingly desire the ability to filter through the noise and quickly discover the products that are most relevant to their needs. Many businesses are implementing product recommender systems to provide this ability to consumers, and the result is often increased sales and more satisfied customers.

However, recommender systems can also have negative consequences for consumers. For example, a recommender system can bias consumers to purchase more expensive products. Additionally, theories of consumer choice-making suggest that recommender systems can sometimes make purchase choices more difficult, resulting …

Improving Sleep And Learning Motivation, And Decreasing Psychological Distress Through Different Modalities Of Written Expression: Controlling For Resilience And Hardiness, Samantha Aarstad Martin

Doctoral Dissertations

College is a time of increased risk for developing psychological distress, poor sleep, and poor academic motivation. Additionally, many students who need mental health services fail to engage in treatment due to perceived barriers. As a result, it is important to find creative ways to reach this group. Research has shown that emotional expression, as well as engaging in written and verbal expression, can be associated with physical, emotional, and cognitive benefits. Specifically, years of research indicate that emotional expression through journaling is highly effective with the college population. Additionally, most college students own a cell phone, typically spending an …

A Qualitative Analysis Of The Effects Of Corequisite Developmental Educational Reform Upon Community College Finances, Casey L. Martin

Doctoral Dissertations

The purpose of this research study was to investigate how a community college’s finances were affected by an organizational change. For this study, the organizational change was the implementation of corequisite developmental education reform. This study used a qualitative research method to collect and analyze data to answer the following research question: How were a community college’s finances impacted when a corequisite developmental, educational reform was implemented? The literature review presented an analysis of different states’ legislation requiring developmental education reform, which included an in-depth review of cases involving institutions from within those states that have implemented corequisite programs according …

Quantum Corrections To The Electromagnetic Response Of Conducting Nanostructures, Neal Blackman

Doctoral Dissertations

The electromagnetic response of conducting nanostructures in the 1 to 10 nm size range is investigated using the quantum box model (QBM). The core purpose of this dissertation is to understand how quantum effects emerge in both the electric and magnetic response of nanostructures in this size range, and in particular, explore how these effects can improve the design of future technology in the fields of plasmonics, metamaterials, and nano-composite materials. One of the primary objectives is to study how quantum effects enhance magnetism in nanoconductors and determine whether quantum resonances give rise to negative permeability, a highly desirable property …

Zinc Oxide Based Nanowire Arrays For Selective Detection Of Multiple Gaseous Analytes At Elevated Temperature, Bo Zhang

Doctoral Dissertations

Zinc oxide (ZnO) based nanostructures represent an important class of gas sensor materials, due to their high surface-to-volume ratio, significant surface band structure bending upon gaseous analyte exposures, good mobility of charge carriers, and good structural stability at elevated temperature. Their usually surface-dominant sensing processes entail the important roles played by nanostructure size, defects, morphologies, and surface absorbate energetics and dynamics. In this dissertation, based on ZnO nanowire array as a gas sensing platform, rational decoration of electronic sensitizers, such as Au nanoparticles, and semiconducting oxide, such as Fe₂O₃ nanoparticles, has been employed to boost its electrical …

The Intersection Of History And Trade: Essays In Trade And Trade Policy, David Travis Freidman

Doctoral Dissertations

In this research I examine the effects that past institutions have on current day economics. In chapters one and two I focus on empirically measuring the impact of past historical trade institutions on current day trade flows. In chapter three I turn my focus to understanding how implicit institutions impact the economic discipline.

My first chapter begins with examining the historical legacy of trading institutions of membership in the ex-Soviet Union and Comecon on current day Russia's bilateral trade flows. The use of long-term data from 1998 to 2016 allows for examination of changes in the legacy effects over time, …

Distributed Cooperative Control Of Multi-Agent Systems Under Detectability And Communication Constraints, Himadri Basu

Doctoral Dissertations

Cooperative control of multi-agent systems has recently gained widespread attention from the scientific communities due to numerous applications in areas such as the formation control in unmanned vehicles, cooperative attitude control of spacecrafts, clustering of micro-satellites, environmental monitoring and exploration by mobile sensor networks, etc. The primary goal of a cooperative control problem for multi-agent systems is to design a decentralized control algorithm for each agent, relying on the local coordination of their actions to exhibit a collective behavior. Common challenges encountered in the study of cooperative control problems are unavailable group-level information, and limited bandwidth of the shared communication. …

Effects Of Nearshore Processes On Carbonate Chemistry Dynamics And Ocean Acidification, Melissa Melendez

Doctoral Dissertations

Time series from open ocean fixed stations have robustly documented secular changes in carbonate chemistry and long-term ocean acidification (OA) trends as a direct response to increases in atmospheric carbon dioxide (CO2). However, few high-frequency coastal carbon time series are available in reef systems, where most affected tropical marine organisms reside. Seasonal variations in carbonate chemistry at Cheeca Rocks (CR), Florida, and La Parguera (LP), Puerto Rico, are presented based on 8 and 10 years of continuous, high-quality measurements, respectively. This dissertation synthesizes autonomous and bottle observations to model carbonate chemistry and to understand how physical and biological processes affect …

Reducing Dropout Rates Of New Hampshire High School Students By Increasing The Compelled Years Of Attendance: An Analysis Of Local Administrator Perceptions Of And Responses To State Law 193:1, Andrew K. Korman

Doctoral Dissertations

In 2007 New Hampshire passed a law, RSA 193:1, that changed the compulsory age of education for all public school students from age 16 to age 18. The purpose of this research is to explore the effect of RSA 193:1 on dropout rates in New Hampshire’s public high schools and to examine the perception of the high school principal in understanding the effect of the law and any differential effects of the law on students. Through an examination of five years of dropout data combined with a survey to current high school principals, findings indicate that there is strong support …

Experiments And Modeling Of Plastic Anisotropy And Ductile Fracture Under Multiaxial Loading, Madhav Baral

Doctoral Dissertations

The implementation of new materials for light-weighting purposes in the automotive industry has often been hindered due to the low ductility of these materials, as well as inadequate empirical knowledge about their fracture behavior and inadequate material modeling techniques. This thesis addresses these issues through extensive experimental and numerical study of plastic anisotropy and ductile fracture of several aluminum alloys and a stainless-steel. The test materials used for this study include AA365 die-casting, AA6013 and AA6111 aluminum sheets, AA6260 aluminum tube and SS304L stainless-steel microtube. The plastic anisotropy is assessed using uniaxial tension, plane-strain tension and disc compression experiments for …

Evaluation And Identification Of Cracking Susceptibility Of Asphalt Binders And Mixtures By Incorporation Of Effects Of Aging On Performance, Runhua Zhang

Doctoral Dissertations

An important aspect which causes a significant effect on performance of asphalt materials is aging. With increase of aging, asphalt materials lose their relaxation capabilities and becomes more susceptible to cracking. Thus, an improved understanding of how aging impacts the cracking behavior of asphalt materials will allow for design of more reliable and durable asphalt pavements. In this study, different laboratory aging levels were performed to simulate different periods of pavement service life. Various performance tests (including Complex Modulus (E*), Simplified Viscoelastic Continuum Damage (S-VECD), Semi Circular Bending (SCB) and Disk Shaped Compact Tension (DCT) tests for asphalt mixtures; Frequency …

Dynamic Performance Of Partially Saturated And Unsaturated Soils, Sayedmasoud Mousavi

Doctoral Dissertations

The vast majority of surface structures are located on or surrounded by unsaturated and partially saturated soil deposits. Previous studies revealed that degree of saturation in soils can significantly impact the seismic performance of geotechnical systems. Yet, the fundamental understanding of the mechanisms by which the degree of saturation impacts their performance during seismic loading is not mature. This Ph.D. dissertation aimed to evaluate and characterize the dynamic response of soils including excess pore pressure generation, induced volumetric deformation, shear modulus, and material damping at different states of saturation and a wide range of degrees of saturation. Three different desaturation …

Improved Catalysis Via Pendant Amines In The Secondary Coordination Sphere, Zane Robert Thistleford

Doctoral Dissertations

The linked problems of renewable energy scarcity and global climate change have grown increasingly dire as the world’s population and standard of living increases, with insufficient societal action to address them effectively. Scientific and technological progress is expected to address the gap between the wants and needs of our civilization, and the available physical and political resources. A truly sustainable solution must use an abundant energy source – sunlight – to simultaneously remove carbon dioxide from our atmosphere and produce carbon-neutral fuel such as hydrogen gas. Photocatalysts can achieve this process directly, while electrocatalysts can use electricity which can be …

"Made Of Queer Magic": Understanding The Experiences Of Pregnancy For Queer Women, Lindsey Rogers

Doctoral Dissertations

Queer families are deciding to use donor insemination or medically assisted reproductive treatments to become pregnant and start their families. Previous research indicates that the process of using medically assisted reproductive treatments may be a stressful experience for queer families due to cisheteronormativity within the system. In addition, research has also revealed that stress during the process of conceiving can impact mental health experiences during pregnancy. However, there is a lack of research on the specific mental health experiences of pregnancy for queer women. The present study used a qualitative research design guided by constructivist grounded theory to examine the …

Diversification Of Functionalized [13]-Macrodilactones, Chengsheng Chen

Doctoral Dissertations

Macrocycles are currently an important area of investigation in drug design and development. Macrocycles can bind target biomolecules and affect various cellular processes due to their ability to modulate their conformations and their occupation of a unique region of chemical space. Our group has worked on the synthesis, structural properties, and biological activity of a class of [13]-macrodilactones in previous studies. Their key structural components include two ester groups, an alkene, and a hinge atom.

This dissertation takes advantage of the modular approach to the synthesis of [13]-macrodilactones and parlays it for the ability to prepare numerous analogs from a …