Digital Commons Network^™

School Choice Competition And How District Leaders Respond To Resulting Fiscal Impacts, Terrie S. Johnson

Doctoral Dissertations

This dissertation examined how superintendents of public-school districts respond to the financial impact of school choice competition. Many U. S. school districts are experiencing funding losses due to the enrollment of students in charter schools and private school voucher programs. The state per-pupil funds follow the student. District leaders must respond to this loss of funding and still maintain high quality instruction and services. The purpose of this research was to explore how leaders develop strategic plans to deal with the fiscal impact of school choice competition. Complexity Leadership Theory was used to view how school district leaders perceive competition, …

Unobtrusive Location-Based Access Control Utilizing Existing Ieee 802.11 Infrastructure, Hosam Alamleh

Doctoral Dissertations

Mobile devices can sense several types of signals over the air using different radio frequency technologies (e.g., Wi-Fi, Bluetooth, cellular signals, etc.). Furthermore, mobile devices receive broadcast messages from transmitting entities (e.g., network access points, cellular phone towers, etc.) and can measure the received signal strength from these entities. Broadcast messages carry the information needed in case a mobile device chooses to establish communication. We believe that these signals can be utilized in the context of access control, specifically because they could provide an indication of the location of a user's device. Such a “location proof” could then be used …

Catalysis By Design: Predicting Materials With Fischer Tropsch Catalytic Activity, Suraj Gyawali

Doctoral Dissertations

Experimental work has been extensive in the catalysis field; however, the cost to move nano-engineered catalysts from the laboratory to industry using only experimental research is prohibitively high. Macroscopic phenomena (i.e. melting, defect formation, miscibility) can be understood in terms of the nano-scale mechanism using molecular simulations. Thus, using molecular simulations in combination with experiments lowers the costs related to design, as simulations can be used to rapidly screen candidate materials, so that experimental efforts can be limited to the catalyst candidates deemed as most promising by simulations. This work employs molecular simulation tools to predict the relative effectiveness of …

Machine Learning Assisted Screening Of Porous Crystalline Materials For Gas Adsorption And Separation, Maryam Pardakhti

Doctoral Dissertations

Archival abstract submitted

Toward The Design Of Novel Biodegradable Materials By Engineering The Protein-Colloid Interface, Kyle Benson

Doctoral Dissertations

This dissertation focuses on development of protein-derived materials, with the goal of incorporation into biodegradable devices such as enzymatic fuel cells or light emitting diodes (LEDs). Proteins are the key building blocks, for their inherent functions, hierarchical 3D structures, diversity of functional groups, and natural biodegradability. The interfaces between proteins and colloidal materials were exploited in the rational design of these materials.

First, enzyme-poly(acrylic acid) (PAA) conjugates with enhanced stability and catalytic efficiency were explored. Conjugation of cytochrome c (cyt c) to PAA dramatically improved cyt c peroxidase activity, achieving 34-fold enhancement in k_cat. Here, polyanionic PAA …

Protein Joinery Using Molecular Cooperation: An Analysis Of The Capsid Stabilizing Interactions In Bacteriophage P22, Kunica Asija

Doctoral Dissertations

Bacteriophage P22 is an icosahedral phage with T=7 symmetry infecting host Salmonella enterica serovar Typhimurium. P22 is an ideal model system to understand the assembly mechanisms of other phages and viruses such as the Herpes Simplex Virus due to the presence of the HK97 fold in their coat proteins. The assembly mechanism is a well-orchestrated event; however, we are yet to comprehend the significant structural changes that proteins undergo during assembly. The end of the assembly process is marked by the formation of a procapsid which then undergoes numerous conformational changes to form a functional, infectious virion. This event is …

Acoustic Detection And Quantification Of Crude Oil, Scott Christopher Loranger

Doctoral Dissertations

The fate and transport of oil droplets from natural and anthropogenic sources is key to understanding the impact of spills and the resilience of marine communities. Without knowledge of natural background levels, it is difficult to determine the response of the marine environment to large influxes of oil. Current estimates of global flux of oil from natural seeps varies by an order of magnitude, and the wide range of estimates is due in part to the lack of sufficient in-situ quantification techniques for oil droplets in the water column. This work is focused on the feasibility of employing broadband acoustics …

Experimental Investigations Of Thermal Pulsatile Boundary Layer Flow, Drummond Biles

Doctoral Dissertations

The need to reliably analyze, predict, and control the transport of mass, momentum, and energy in turbulent boundary layers is critically important across a broad spectrum of technological applications and scientific disciplines. While there has been extensive–and continuing– research investigating laboratory-scale canonical wall-bounded flows, beyond the scope of these well-studied flows there exists a broad range of application relevant flows that are far less studied. The theme of this dissertation research is to study a non canonical flow, specifically to study coupled momentum and thermal transport in pulsatile boundary layer flows.

The primary contributions of the present work are (1) …

Informal Caregiver Identity: Voluntary Job Fit, Teamwork, And Tools, Erica Spunt Jablonski

Doctoral Dissertations

According to the Family Caregiver Alliance, an informal or family caregiver is “an unpaid individual . . . involved in assisting others with activities of daily living and/or medical tasks.” As informal caregiving in the United States has increased, research on the topic has been published in a myriad of disciplines (e.g., sociology, nursing, social work, and medicine). The literature has defined informal caregivers (ICGs), described their role and its impacts, detailed the costs and benefits of informal caregiving, and evaluated interventions to assist ICGs. Scholars have also investigated more natural, less experimental use of informational and support resources for …

Mules, Fuels, And Fusion: Energy, Entropy, And The Crossing Of The Panamanian Transit Zone, 1848-1990, Jordan T. Coulombe

Doctoral Dissertations

Between 1848 and 1990 Americans attempted to construct numerous infrastructural projects in Panama in hopes of bridging the Isthmus and connecting the seas. These schemes ran the gamut from the creation of the Panama railroad in the early 1850s through attempts to detonate nuclear explosives to create a sea-level canal in the 1960s. While these projects seem quite alien to one another, these two plans, and other attempts to cross the Isthmus, were unified by their shared reliance on energy’s capacity to overcome the entropy of the Panamanian environment. In order to reshape Isthmian landscapes, American engineers, scientists, and policymakers …

Computational Studies Of Protein-Inhibitor Interactions, Mohammadjavad Mohammadi

Doctoral Dissertations

In this thesis work, I conducted large-scale molecular dynamics (MD) simulation studies of interactions of enzymes and signaling proteins with inhibitory ligands. Specifically, I have studied three classes of proteins: the first part of my thesis reports studies on the hydrogen-producing [FeFe]-hydrogenase enzyme, the second part reports on studies of regulatory proteins from the G-protein coupled receptor (GPCR) family, and the third part reports on studies of the phosphodiesterase (PDE) enzyme family.

In the first part, I studied the problem of [FeFe]-hydrogenase sensitivity to the presence of inhibitory gases oxygen (O2) and carbon monoxide (CO) that cause irreversible damage to …

Investigation Into The Flow Physics Of Large Experimental Offshore Wind Farms In A Turbulent Boundary Layer Wind Tunnel, John James Turner

Doctoral Dissertations

Large offshore wind turbine array power plants will soon be appearing along the United States' eastern seaboard. With recent advances in technology, turbines have been growing in diameter and arrays have been growing in scale, but not without technical challenges. There exist knowledge gaps in the fluid dynamics that govern the interaction of the incoming atmospheric boundary layer with the wakes of the turbines and the sequential wake-wake interactions that result in an unavoidable decreased bulk power production compared to predicted capacity from the array.

Wind farm experiments were conducted with scale model wind turbines in a high Reynolds number …

Climate Adaptation For Coastal Road Infrastructure In The Northeast, Jayne Fifield Knott

Doctoral Dissertations

The climate is changing, and these changes are expected to accelerate. In the northeast region of the United States, temperatures and sea levels are projected to rise with climate change. These changes have the potential to impact coastal communities in many ways, but this dissertation focuses on climate-change impacts to pavement life. A well-maintained and fully functional roadway system is essential to maintaining a high quality of life and economic vitality in a region. When pavements fail prematurely, the agency and user costs of full-pavement rehabilitation or reconstruction are much higher than the costs of routine maintenance and pavement over-lays. …

Evaluation Of Structural Contribution Of Asphalt Mixtures Through Improved Performance Indices, Rasool Nemati

Doctoral Dissertations

A variety of approaches are available to design the pavement structures. These approaches are generally divided into two main categories as empirical and mechanistic-empirical (M-E) methods. The most widely used empirical method is the AASHTO 1993 design approach which uses material specific coefficients (layer coefficients) to quantify the structural capacity provided by each pavement layer. These coefficients are experimentally developed values from the AASHO road test which was conducted in the early 1960s and are based on statistical regressions. Almost no fundamental or engineering mixture properties or explicit failure criterion were used in their original development. On the other hand, …

Design, Mechanical Experiments And Modeling On A New Family Of 3d Printed Hybrid Chiral Mechanical Metamaterials With Negative Poisson’S Ratio, Yunyao Jiang

Doctoral Dissertations

Emerging in the last decade, mechanical metamaterials have many engineering advantages due to unusual mechanical properties. Auxetic (with negative Poisson’s ratio) mechanical metamaterials, as an important family of these materials, have broad engineering applications including the design of new materials with increased indentation resistance, shear resistance, energy absorption capability and variable permeability.

Chiral auxetic mechanical metamaterial is a sub-family of the auxetic material, which is with a geometry that is non-superposable on its mirror image. Compared to symmetric auxetic materials, such as re-entrant honeycombs or periodic porous materials, which have random handedness after instability, chiral materials have deterministic handedness and …

Development And Testing Of Positron Identification By Coincident Annihilation Photons (Picap), Dan Lam Tran

Doctoral Dissertations

Moderate energy positrons (~few to 10 MeV) have seldom been observed in the Heliosphere, due largely to the lack of dedicated instruments. Deep-space measurements of these positrons would have implications in the study of Solar energetic particle events and the transport and modulation of Galactic cosmic rays in the Heliosphere. Positron Identification by Coincident Annihilation Photons (PICAP) is a detector scheme to measure these positrons by simultaneously detecting the two 0.511- MeV gamma-ray photons emitted from negatron-positron annihilation of stopping positrons. PICAP is intended for deep-space missions with severe limits on mass, power, and telemetry. This dissertation details the development …

Interdependence Of Flow And Shape Morphological Dynamics For Flow-Induced Erosion Of Bluff Bodies, Michael Paul Allard

Doctoral Dissertations

Flow-induced erosion encompasses all processes in which fluid-solid interactions result in the

removal and transport of material from the solid. The removed material may change its physical

state and/or chemical composition and may be redeposited onto the solid body or advected away

by the fluid and deposited elsewhere. Common to all flow induced erosion processes is that they

involve an eroding surface, and eroding agent, and a fluid flow which delivers the eroding agent to

the eroding surface. Consequently, the study of erosion is difficult as it requires detailed knowledge

of the material, mechanical, and/or thermophysical properties of the eroding …

Spatial Control Of Gold-Silica-Quantum Dot Nanostructures And Single Particle Optical Study Of Plasmon-Exciton Strong Coupling Effect, Yi Luo

Doctoral Dissertations

Metallic nanoparticles can generate collective oscillation of conduction electrons when excited by incident light. This unique light-matter interaction is termed as localized surface plasmon resonance (LSPR) and offers the possibility of manipulating light well below the diffraction limit. This extreme concentration of light also greatly influences the absorption and decay processes of the nearby Quantum Dots (QD). When plasmon-exciton interaction enters strong coupling regime, the energy coherently oscillates between the QD and the plasmonic cavity. Optical studies at the single particle level of hybrid Au-QD structures with strong-coupling can help us understand the origin of this phenomena as well as …

Identifying Clogging Factors And Thresholds Of Greenhouse Irrigation Pipes, Juan Cabrera Garcia

Doctoral Dissertations

Clogging of irrigation systems affects irrigation uniformity, water use, crop yields, and production costs. The objectives of this research were to: 1) Evaluate if published classification guidelines could predict and identify the causes of clogging in greenhouses; 2) Determine if pipe materials and flow frequency affect biofilm accumulation; 4) Determine if biofilms inside pipes affect plant health; and 5) Determine total suspended solids (TSS) thresholds that affect the performance of pressure–compensated drippers with anti–drain mechanism. The first study revealed that the current classification guidelines serve as an indicator of relative risk of clogging, but not as predictors. The assumptions of …

Anion Exchange Membrane Fuel Cell Performance In The Presence Of Carbon Dioxide, Jacob Wrubel

Doctoral Dissertations

Anion Exchange Membrane Fuel Cells (AEMFCs) offer some possible advantages over their Proton Exchange Membrane (PEM) counterparts due to more facile oxygen reduction reaction kinetics (enabling cheaper catalysts), easier water management & balance of plant, cheaper membrane materials, and improved stability of fuel cell stack materials. However, AEMFCs perform significantly worse when exposed to carbon dioxide (CO₂), which is present in most applications. Furthermore, because CO₂ is so pervasive inside the AEMFC system, its effects are difficult to isolate experimentally. Therefore, a modeling approach was developed which can offer independent control of membrane properties and operating conditions, …

Silk Fibroin And Hydroxyapatite Composites For Bioresorbable Bone Fixation Devices, Bryant Heimbach

Doctoral Dissertations

Every year there are approximately 9 million bone fractures in the United States, and 30% of these require an internal fixation device to help heal. Currently, the gold standard for fixation devices relies on the use of metals because of their high mechanical properties and bioinertness. However, metal implants often require a second surgery to remove them because they cause stress shielding and metal ion leaching. Current bioresorbable fixation devices on the market have poor mechanical properties and are limited to use in non-load-bearing applications (i.e. maxillofacial fractures). As such, there remains a gap in the fracture fixation devices on …

Methods In Homology Inference, Nicholas J. Cavanna

Doctoral Dissertations

In this dissertation we introduce novel techniques to infer the shape of a geometric space from local data. The major contribution of this research is that the techniques aim to minimize the hypotheses of the sample and the space compared to existing results in the field.

We first prove an equivalence between the two standard geometric sampling methods: adaptive and uniform. From this we create a collection of topological interleavings derived from this equivalence, which we use to compute the homology of an arbitrary Euclidean compact set only assuming a bound on the weak feature size of the domain and …

Developing Portable Tools Based On Magnetophoresis For Accessible Clinical Diagnostics, Stephanie Knowlton

Doctoral Dissertations

Modern technological advancements allow us to study human cells with an extraordinary level of detail and accuracy. However, the impact of these technologies on public health remains limited by their complexity, cost, and inaccessibility. Hence, there is a need for user-friendly, inexpensive tools that can be used at the point of care, in limited-resource settings, and at home. Therefore, we aim to develop a platform technology that can perform a variety of medical diagnostics to rapidly provide important information in order to best inform medical decisions. Magnetophoresis is a phenomenon that enables precise manipulation of particles that do not necessarily …

Computational Methods For The Analysis Of Single-Cell Rna-Seq Data, Marmar Moussa

Doctoral Dissertations

Single cell transcriptional profiling is critical for understanding cellular heterogeneity and identification of novel cell types and for studying growth and development of tissues and tumors. Leveraging recent advances in single cell RNA sequencing (scRNA-Seq) technology requires novel methods that are robust to high levels of technical and biological noise and scale to datasets of millions of cells. In this work, we address several challenges in the analysis work-flow of scRNA-Seq data: First, we propose novel computational approaches for unsupervised clustering of scRNA-Seq data based on Term Frequency - Inverse Document Frequency (TF-IDF) transformation that has been successfully used in …

Whimp Is A Wasp-Family Actin Nucleation-Promoting Factor That Functions In Cell Motility, Shail Kabrawala

Doctoral Dissertations

Actin filament assembly is regulated by many actin-binding proteins that function to maintain cell shape and structure, enable vesicle trafficking, control motility, and support DNA repair. Identifying these regulatory proteins is critical for a comprehensive understanding of the dynamic organization of actin in various cellular processes. In the last decade, the discovery of new Wiskott-Aldrich Syndrome Protein (WASP) family actin nucleation factors such as WASH, WHAMM, and JMY has significantly contributed to our understanding of actin cytoskeleton functions, and opened new avenues of research into the physiological roles of these proteins in membrane trafficking. I have identified a new WASP-family …

Cholesterol-Based Polymeric Nanoparticles For Improved Chemotherapy, Laura Gonzalez

Doctoral Dissertations

Polymeric nanoparticles from amphiphilic copolymers are deemed as flexible platforms for effective delivery of chemotherapeutic drugs to tumor tissues. The use of cholesterol as the hydrophilic segment can confer stability upon dilution and high drug loading capacity to these type of nanoparticles due to the tendency of cholesteryl groups to aggregate and form liquid crystal phases. On the other hand, the incorporation of polyethylene glycol as the hydrophilic block provides colloidal stability and reduced opsonization. Building on previous research in the laboratory, the overall goal of the present dissertation was to further advance the development and understanding of novel and …

Misfit At The Intersection Of Measurement Quality And Model Size: A Monte Carlo Examination Of Methods For Detecting Structural Model Misspecification, Graham Rifenbark

Doctoral Dissertations

Archival abstract submitted

Towards Security Analysis Of Openstack, Hoda Maleki

Doctoral Dissertations

OpenStack is the prevalent open-source, non-proprietary package for managing cloud services and data centers. It is highly complex and consists of multiple inter-related components which are developed by separate, loosely coordinated groups. All of these properties make the security analysis of OpenStack both a crucial mission and a challenging one. In this dissertation, we demonstrate how we can provide a rigorous, perceptible and holistic security analysis of OpenStack. We base our modeling and security analysis in the universally composable (UC) security framework, which has been so far used mainly for analyzing the security of cryptographic protocols. Indeed, demonstrating how the …

Unraveling The Role Of Interfaces In The Deformation And Failure Behavior Of Metallic Materials Under Dynamic Loading Conditions, Jie Chen

Doctoral Dissertations

Design of next-generation high strength metallic materials for damage-resistant applications relies on a fundamental understanding of the deformation mechanisms and failure behavior of these materials under dynamic loading conditions. The dynamic strength of metals is typically characterized based on the “spall strength” defined as the peak tensile pressure the metal can withstand prior to failure. For pure FCC metals, the capability to increase the spall strength is limited due to insufficient microstructural features that can be used to tailor/modify the deformation and failure behavior under dynamic loading conditions. The current understanding of the role of grain boundaries and deformation twinning …

Upkeep: Maintenance In American Representations Of Work, 1945-Present, Brandon Benevento

Doctoral Dissertations

This study investigates maintenance as an under-theorized component of social criticism in American novels, 1945 to the present. In this, it contributes a literary argument to growing interdisciplinary study of maintenance. “Upkeep” argues that authors of novels use maintenance, often unconsciously, to link representation of characters working in discreet settings to larger systemic and structural critique. At the same time, authors often elide forms of maintenance, for example the upkeep of domestic space. As such attention to representation of maintenance offers a critical reading tool which illuminates a text’s political and cultural commitments and literary agenda.

After establishing a range …