Digital Commons Network^™

Novel Algorithms For Some Fundamental Big Data Problems, Abdullah-Al Mamun

Doctoral Dissertations

In this digital era data sets are growing rapidly. Storing, processing, and analyzing large volume of data require efficient techniques. These techniques deal with big data problems by providing time efficient methods, effective external memory algorithms, parallel and high performance solutions, and so on. This thesis studies three important areas of big data problems and presents state of the art approaches to address them.

The first part of this thesis discusses the k-mer counting problem. A massive number of bioinformatics applications require counting of k-length substrings in genetically important long strings. Genome assembly, repeat detection, multiple sequence alignment, …

Consequences Of Antiepileptic Drug Exposure During Postnatal Liver Development On Cytochrome P450 Expression And Metabolism, Stephanie C. Piekos

Doctoral Dissertations

Adverse reactions or lack of therapeutic efficacy are commonly encountered challenges when prescribing pharmaceutical drugs to patients. These undesirable outcomes highlight the large amount of interindividual variability in drug responses, and can often be attributed to differences in drug metabolism and clearance rates among patients. Patient age and current medication usage are two variables that can increase or decrease the expression and activity of drug metabolism by cytochrome P450 enzymes (CYPs), thus impacting responses to other drugs. Neonates, infants, and children, express CYP enzymes at different levels than adults due to immature liver functions, and this causes drug responses to …

Impact Of Conductivity On The Electrochemical Behavior Of Conversion Metal Oxide Anodes In Li-Ion Batteries, Alessandro Palmieri

Doctoral Dissertations

In this thesis, various metal oxides have been investigated as innovative anode active materials for next generation Li ion batteries. Specifically, metal oxides have been proved to have higher specific and volumetric energy density than commercial graphitic anodes, wider operating voltage window and are environmentally friendly. However, pure metal oxides have been demonstrated to be characterized by poor reaction reversibility leading to high instability and short battery cycle life. It has been found that the key to achieving high reaction reversibility, or at least stabilizing the capacity, is to increase the inter-particle and/or intra-particle conductivity.

One effective strategy to increase …

Surface Plasmon Resonance And Liquid Chromatography-Mass Spectrometry Techniques For Antibody Bioanalysis, Min Shen

Doctoral Dissertations

Archival abstract submitted

Methods For Imitation Learning And Human Intention Inference: Towards Seamless Human-Robot Collaboration, Harish Ravichandar

Doctoral Dissertations

Robots are becoming integral parts of our environments, from factory floors to hospitals, and all the way to our homes. Unlike robots enclosed in cages performing repetitive tasks with high precision, there is an ever-increasing need for robots that can seamlessly interact and collaborate with humans in close proximity. Hence, it is imperative that robots are provided with the tools necessary to both safely and efficiently collaborate with their human partners. For achieving safe and efficiently human-robot collaboration, methods to infer humans intentions and methods for quick robot programming are required. To this end, this dissertation presents methods that fall …

Development Of Microscopy Systems For Super-Resolution, Whole-Slide, Hyperspectral, And Confocal Imaging, Kaikai Guo

Doctoral Dissertations

Optical microscope is an important tool for researchers to study small objects. In this thesis, we will focus on the improvement of traditional microscope systems from several aspects including resolution, field of view, speed, cost, compactness, multimodality. In particular, we will investigate computational imaging methods that bypass the limitations with traditional microscope systems by combining the optical hardware design and image processing algorithm. Examples will include optimizing illumination strategy for the Fourier ptychography (FP), developing field-portable high-resolution microscope using a cellphone lens, investigating pattern-illuminated FP for fluorescence microscopy, demonstrating multimodal microscopic imaging with the use of liquid crystal display, achieving …

Novel Optimization-Based Algorithms For Dynamic Resource Management In Complex Systems, David Sidoti

Doctoral Dissertations

This dissertation contains several foci in which optimization-based approaches are developed to obtain optimal or near-optimal solutions to NP-hard dynamic resource management problems that require the integration of spatio-temporally evolving intelligence and weather (meteorology and oceanography) data. Three primary topics of research are addressed: (i) asset allocation for counter-drug trafficking, (ii) multi-objective (ship) path planning, and (iii) fastest-path sailing boat routing. We approach all three problems in a general way for application to multiple domains, while utilizing domain-specific knowledge available in order to help condense the complex problem and decision spaces. The first two topics involve multiple, often competing, objectives …

Coupling Transport Phenomena To Contamination And Durability In Polymer Electrolyte Fuel Cells, Charles J. Banas

Doctoral Dissertations

Polymer electrolyte fuel cells (PEFCs), while a promising clean energy technology, suffer from a lack of durability, especially tolerance to impurities. This work studies both foreign cationic contamination in the cathode, and detection of fuel impurities through the development of a hydrogen contaminant detector (HCD).

The role of mass transport in foreign cationic contamination of PEFCs is studied through the extraction of a gas diffusion media (GDM) from a cell that experienced sudden shutdown during in situ foreign cation contamination. Significant cation salt precipitation is examined using x-ray computed tomography, with the distribution examined using an in-house Matlab code. Results …

Nanoarmoring Of Enzymes In Ordinary Paper, Caterina Riccardi

Doctoral Dissertations

This dissertation focuses on the development of a simple, efficient, and versatile method for enzyme stabilization and extends it into a universal approach for stabilization of enzymes on solid porous supports such as cellulose so that they can be used to produce novel enzyme biomaterials for advanced biocatalysis and biosensing applications. The novelty of this work is in the development of a universal and simple method for the stabilization of any enzyme, which is currently not available. Many enzyme conjugation methods are either enzyme-specific, or they require complex chemistries that significantly inactivate the enzyme.

Enzymes were first conjugated to the …

Iridium Oxide (Iro2) As A Top Electrode For Ferroelectric Micro-Electro-Mechanical Systems (Mems) Devices For Radiation Rich Environments, Manuel Rivas

Doctoral Dissertations

The multifunctional properties of ferroelectric materials make them ideal components for numerous applications including for extreme environments such as space. Iridium oxide (IrO2) electrodes have been demonstrated to improve the lifetime of ferroelectric memory devices, however little is known about its influence on the electromechanical properties important for ferroelectric microelectromechanical systems (MEMS). The performance of thin film lead zirconate titanate (PZT) based MEMS is affected by the processing conditions, composition, device design, electrode materials, and the environment. This work details the development and characterization of iridium oxide electrodes for PZT based microelectromechanical and pyroelectric-harvesting systems, fabrication induced defects, and design …

Low-Cost, High-Contrast, And Miniature Optical Imaging Systems For Clinical Applications, Mohsen Erfanzadeh

Doctoral Dissertations

Reducing the cost and size and enhancing the contrast of optical imaging systems improve their potentials for clinical applications. In this dissertation, we describe our endeavors towards development of low-cost and compact photoacoustic microscopy and spatial frequency domain imaging systems as well as improvement of photoacoustic tumor imaging using a specifically designed photoacoustic contrast agent.

Chapters two and three focus on the development of low-cost and compact laser diode based photoacoustic microscopy systems. We first provided an improvement in light delivery of laser diode based photoacoustic microscopy systems that enables imaging biological tissue with high signal to noise ratio. We …

Low Thermal Conductivity Yag-Based Thermal Barrier Coatings With Enhanced Cmas Resistance, Rishi Kumar

Doctoral Dissertations

Thermal barrier coatings (TBCs) are insulating coatings used in gas turbine engines to improve energy efficiency. The current choice of TBC material i.e. yttria stabilized zirconia (YSZ), is limited to temperatures of less than 1200°C because of (a) undesirable phase transformations and (b) prone to the attacks from calcium-magnesium-aluminum-silicate (CMAS) deposits.

In this research, the solution precursor plasma spray (SPPS) was employed for the further development of yttrium aluminum garnet (YAG) coatings previously developed at UConn. Thermal conductivity of SPPS YAG was reduced (0.58 W/mK at 1300 °C) by process modifications to generate microstructures with layered porosity termed inter pass …

Multizonal Scaffolds For Osteochondral Tissue Engineering, Drew Clearfield

Doctoral Dissertations

Osteochondral tissue is a biphasic material comprised of articular cartilage integrated atop subchondral bone. Damage to this tissue is highly problematic, owing to its intrinsic inability to regenerate functional tissue in response to trauma or disease. Further, the function of the tissue is largely conferred by its compartmentalized zonal microstructure and composition. Current clinical treatments fail to regenerate new tissue that recapitulates this zonal structure. Consequently, regenerated tissue often lacks long-term stability. To address this growing problem, we propose the development of tissue engineered biomaterials that mimic the zonal collagen orientation and composition of osteochondral tissue. First, a unidirectional freeze …

Polychromatic Optical Forces In Diatomic Systems, Scott Edwin Galica

Doctoral Dissertations

This dissertation discusses an experiment to demonstrate the application of the stimulated bichromatic optical force (BCF) on the diatomic molecule calcium monofluoride (CaF). The research demonstrates the deflection of a supersonic beam of CaF through the application of BCF under a variety of conditions, highlighting distinctive characteristics of the force. Results show that the measured deflection of the molecular beam is consistent with the behavior of BCF under the tested conditions. In particular, we have measured a predicted reversal in the direction of the force as well as an applied force which exceeds the radiation pressure force. Detailed modeling of …

Life-Cycle Fatigue Performance Of Coastal Slender Bridges Subject To Multi-Hazards, Jin Zhu

Doctoral Dissertations

Serving as critical links in the transportation network for coastal regions, costal slender bridges could constantly experience complex dynamic interactions with strong winds and/or high waves during extreme weather conditions, in addition to moving vehicles, such as cars, trucks, or trains. Continuously repeated stress cycles as well as corrosive coastal environments could cause significant fatigue damage accumulations at complicated weldments of the orthotropic steel deck (OSD) during lifetime, which could be critical and might affect structural safety and reliability. Nevertheless, fatigue is a damage accumulation process that is subjected to various aleatory and epistemic uncertainties from ambient environment, model simplifications, …

Prediction-Based Opportunistic Sensing For Energy-Efficiency And Reliability In Distributed Sensor Networks, James Z. Hare

Doctoral Dissertations

Distributed Sensor Networks (DSN) containing a large number of sensors nodes are rapidly advancing to perform automated tasks for a variety of applications (e.g. Target Tracking). One of the main problems studied in DSN is the Target Coverage problem, where the objective is to maximize the network lifetime while ensuring that all targets are covered during all times. Therefore, the main challenges in developing a DSN are network control strategies for energy-efficiency and resilience in the event of sensor failures. This thesis presents the \emph{Prediction-based Opportunistic Sensing for Energy-efficiency} (POSE) algorithm, which aims to address these challenges by designing a …

Modulating Aged Macrophages And Osteoprogenitors With A Calcium Phosphate Drug Delivery System, Jumana Alhamdi

Doctoral Dissertations

Older adults suffer from weakened and delayed bone healing due to age-related alterations in bone cells and in the immune system. Given the interaction between the immune system and skeletal cells, therapies that address deficiencies in both the skeletal and the immune system are required to effectively treat bone injuries of older patients. The sequence of macrophage activation observed in healthy tissue repair involves a transition from a pro-inflammatory state followed by a pro-reparative state. In older patients, inflammation is slower to resolve and impedes healing. The goal of this dissertation was to design a novel drug delivery system for …

Three Essays On Information-Securing In Organizations, Yaojie Li

Doctoral Dissertations

This dissertation is intended to interpret, analyze, and explain the interplay between organizational structure and organizational information systems security by mapping structural contingency theory into three qualitative studies. The research motivation can be attributed in two ways. First, Johnson and Goetz's (2007) conception of embedding information in organizations as part of their field research interviewing security executives serves as a methodological inspiration for the series of three studies reported here. The point that security should be infused into organization activities instead of serving as a "bolted-on" function is a central tenet guiding the development of this dissertation. Second, a macro …

Characterization And Numerical Modeling Of Advanced Automotive Lightweighting Materials, Nengxiu Deng

Doctoral Dissertations

The automotive industry is being challenged to manufacture vehicles to meet the fuel- efficiency, emission and crashworthiness. New generation steels such as high strength steels (HSS) and advanced-/ultra-high strength steels (AHSS/UHSS) are gaining popularity in the automotive industry due to their appealing strength-to-weight ratios. The utilization of these steels has prompted research to seek solutions on issues arising during sheet metal forming processes, e.g., springback prediction/control, edge cracking prediction and avoidance, formability performance prediction and enhancement, etc. This thesis is focused on developing experimental techniques to characterize the forming properties for AHSS, on exploring fundamental principles of their mechanical behavior …

Seismic Site Response Of Partially Saturated Soil Layers, Morteza Mirshekari

Doctoral Dissertations

Accurate prediction of seismic ground response plays a vital role in earthquake-resistant, sustainable, and cost-effective design of infrastructure. Seismic response of unsaturated soil layers may differ from that of saturated or dry soil deposits. Importantly, surficial soil layers are often partially water-saturated, however, site-specific design procedures only consider ground in either dry or fully saturated conditions. Further, seasonal water table fluctuation introduces additional uncertainty in site-specific response analysis. This research investigates the effect of soil-water interaction on seismic site response of soil layers both experimentally and numerically. To that end, initially, preliminary numerical analyses were performed using the DEEPSOIL software …

Shipworms And The Making Of The American Coastline, Derek Lee Nelson

Doctoral Dissertations

This dissertation tells the forgotten history of the American teredo epidemic. During the late nineteenth and early twentieth centuries, an assortment of native and invasive wood-boring marine organisms, known collectively as “teredo,” swept through the ports and harbors of the United States. Teredo’s penchant for wood, both for shelter and sustenance, made wharves and wooden ships easy targets. Because teredo enters timber as tiny juveniles, and grows to maturity beyond view, it was often detectable only after a wharf had collapsed or a ship had sunk. Teredo’s unpredictability grated on people so much so that the borer was rarely mentioned …

Mechanistic Studies Of The Complete Electrochemical Oxidation Of Ethanol Into Co2 Over Platinum-Based Core-Shell Nanocatalysts, Guangxing Yang

Doctoral Dissertations

Direct ethanol fuel cells (DEFCs) are a promising technology for the generation of electricity via the direct conversion of ethanol into CO2, showing higher thermodynamic efficiency and volumetric energy density than hydrogen fuel cells. However, implementation of DEFCs is hampered by low selectivity of CO2 generation at the anode where the ethanol oxidation reaction (EOR) happens. Therefore, anode catalysts with high reactivity for the EOR and high selectivity for CO2 generation via breaking C-C bond are highly needed. To evaluate the catalysts’ capability of splitting C-C bond of the ethanol molecule, highly sensitive CO2 detection technique was developed in this …

The Activity Of Becoming A Second-Career Teacher, Michael Hildebrandt

Doctoral Dissertations

This is a study of three second-career teachers’ experiences of self transformation and the processes of socialization and identity formation each undergoes during his or her first three to five years as a full-time teacher. Each narrative offers a means through which to explore how liminal identity is at play during the transition to a new career—an experience that reshapes the experiences and self-understandings of individuals in the process of becoming teachers. The narratives that emerge from in-depth interviews showcase individuals with multi-faceted lives who have engaged in a multitude of personal and professional activities throughout their life course and …

Structure And Mechanical And Tribological Properties Of Magnetron Sputter Deposition Of Stainles-Steel Nitride And Carbide Thin Films With Transition Metal Additives, Faisal Alresheedi

Doctoral Dissertations

Since the initial discovery of the S-phase in 1985, understanding the structural nature of this phase and the anomalous shift of the (200) diffraction peaks has been a challenging problem. Austenitic stainless steels, ternary Fe–Cr–Ni alloys, like AISI 304, demonstrate excellent corrosion resistance and relatively good levels of toughness and strength. For this reason, they are widely used engineering materials in areas such as aerospace, construction buildings, piping, telecommunications, chemical and petrochemical applications. However, stainless steels have a relatively low hardness, and this leads to a poor wear resistance, resulting in a short lifetime that limits its use in industrial …

New Model For Bridge Management System (Bms): Bridge Repair Priority Ranking System (Brprs), Case Based Reasoning For Bridge Deterioration, Cost Optimization, And Preservation Strategy, Nasser Yari

Doctoral Dissertations

Most public transportation agencies (Such as, state department of transportations (DOTs) and department of public works for cities and towns.) in the United States are constantly pursuing ways to improve bridge asset management to optimize their use of limited available funds for rehabilitation, replacement, and preventive maintenance. Given the realities of available funding, there is a significant difference between available funds and funds required for maintaining bridges in good condition. The proper preventative maintenance and treatments should be performed at the right time to be cost effective and extend the life of bridges. Neglecting maintenance can cause higher future costs …

Development Of Protein Display Systems And Genetic Tools For Spore-Forming Bacteria, Erin Drufva

Doctoral Dissertations

One major area of synthetic biology is to engineer microbial cells and subcellular systems for diverse applications including biosynthesis, biocatalysis, therapeutics, drug delivery, and bioremediation. For most applications, robust cellular systems are preferred for longer activity half-life and resistance to harsh environments. Two projects related to robust cellular systems involving Gram-positive bacteria are presented in this work. One is to develop thermostable genetic reporters for Geobacilli species and the other is to display an enzyme on the Bacillus subtilis spore surface to enhance its robustness and present an alternative to purified enzymes for industrial applications.

Bacillus subtilis and Geobacillus thermoglucosidans …

Atomic Structure Studies Of 2d Materials And Advancement Of Dynamical Leem/Uleed-Iv Analysis, Zhongwei Dai

Doctoral Dissertations

Two-dimensional (2D) materials have attracted much attention as an emerging category of materials over the past decade due to their novel mechanical, optical and electronic properties with many potential applications in photovoltaics, photo-catalysts, and modern electronics. However, the detailed atomic structural information has been rarely experimentally investigated due to the following difficulties: (i) the limited sample size of 2D materials prepared through mechanical exfoliation of a few µm, and (ii) the easy oxidation and surface instability of various 2D materials under high energy probing techniques. Selected area low-energy electron diffraction analysis (µLEED-IV performed in a low-energy electron microscopy (LEEM) system, …

Synthesis Of Metal Oxide Nanoparticles And Mesocrystals In An Interphase Droplet Reactor, Brian Zukas

Doctoral Dissertations

The attractive properties of nanoparticles and nanostructures has driven their integration into a wide range of modern technologies. Synthesis of nanoparticles in droplet flow reactors offers a solution to the shortcomings of batch reactors. The interphase droplet reactor presented in this work maintains the advantages of a droplet flow reactor while accomplishing reagent addition through mass transfer from the continuous phase to the droplet phase. In this work, sodium hydroxide in a continuous phase of 1-octanol diffuses into aqueous droplets containing a metal salt, initiating nanoparticle synthesis. An acid-base titration confirmed that increasing the total flow rate increased the rate …

Performance Based Evaluation Of Cracking In Asphalt Concrete Using Viscoelastic And Fracture Properties, Mirkat Tamire Oshone

Doctoral Dissertations

Cracking is one of the major distresses encountered in pavements. Pavements that fail prematurely due to cracking precipitate lower ride quality, elevate the chance of road accidents, and cause agencies to spend considerable amount of public funds on pavement maintenance and rehabilitation. As part of the concerted endeavor to ensure high performing pavements, extensive research is being undertaken throughout the United States to develop more effective and efficient performance based materials selection and specification procedures as well as mechanistic-empirical (M-E) methods for pavement cracking performance evaluation. However, agencies have been hesitant to introduce the methods to their specifications, pavement evaluation …

Perceptions Of Barriers To Leadership Appointment And Promotion Of African American Female Commissioned Officers In The United States Military, Beverly Henderson Davis

Doctoral Dissertations

The U.S. military is perceived by many to be the example of workplace meritocracy, but historical studies have shown that the perceptions of African American female commissioned officers run counter to that belief. The military has as its goal the movement from a diverse fighting force to one that is totally inclusive of all members. The purpose of this study was to gather insights into whether the military has moved toward full integration from the viewpoint of the demographic that has shown the least confidence in the accomplishment of that task.

This qualitative study involved 12 participants: active duty, retired, …