Digital Commons Network^™

Effects Of Untrained Earmold Impression Taking On Custom Hearing Protector Device Performance, Kelly R. Pack

Doctoral Dissertations

Today's consumer is increasingly turning to the internet for both healthcare information as well as the purchase of custom hearing protection devices (HPDs). These HPDs are often cast from do-it-yourself home ear impression kits that include a syringe and silicone earmold impression material to be injected into the ear canal. Although not required by law, earmold impressions have typically been taken by medical professionals and other individuals formally trained in the procedures and safety measures of effective earmold impression taking. The main purpose of this study was to determine if do-it-yourself earmold impressions produce HPD's with lower attenuation levels than …

Fault And Performance Monitoring In Wireless Lans, Xian Chen

Doctoral Dissertations

Air sniffering is a widely-used and effective technique to monitor access points in WLANs. This technique, however, requires a large number of sniffers and generates a large amount of data. These challenges can be overcome by channel sampling, where each sniffer samples the network traffic by visiting multiple channels periodically. In the first part of the dissertation, we address an important problem in channel sampling, namely, how to select channels for sniffers to reduce monitoring cost. Specifically, we study two channel selection problems. Both of them require that each AP be monitored by at least one sniffer, and in addition, …

The Geomorphic And Hydrologic Impact Of Beaver Dams On Headwater Streams In Northeastern Connecticut And Implications For River Restoration, Denise Burchsted

Doctoral Dissertations

The billion-dollar river restoration industry relies primarily on the concept of a free-flowing river to set restoration targets. However, rivers include natural barriers such as beaver dams, wood jams, glacial deposits, and bedrock constrictions. Following European colonization, most of these barriers were removed; some were replaced with far more homogenous ones such as human dams and road crossings. Although the biota intended to benefit from restoration evolved in rivers with natural barriers in place, little is known about the functions of the barriers that have been lost. Beaver dams—the subject of this dissertation—are just one type of the many natural …

Investigation Of Factors Affecting Protein-Silicone Oil Interactions, Nitin Dixit

Doctoral Dissertations

Silicone oil, a lubricant in pharmaceutical containers, has been implicated as a risk factor for protein formulations because of its tendency to cause protein aggregation and/or particulate generation. Due to a lack of published data in this area, it is not clear as to what extent this risk can be generalized across protein pharmaceuticals. A fundamental understanding of the factors that influence protein-silicone oil interactions can help in better understanding the implied risks to drug product stability. The technique of quartz crystal microbalance with silicone coated quartz crystals, mimicking the lubricated syringe surface, was used for the studies. The frequency …

Influence Of The Chemical Composition Of Dielectric Fluid On Partial Discharge Characteristics For Diagnostic Purposes, Dominique A. Bolliger

Doctoral Dissertations

This thesis provides an understanding of the correlation in change of partial discharge (PD) characteristics with the chemical nature of impurities present within dielectric fluids when measured in a needle-plane geometry. Such knowledge could prove vital to support development of a field-deployable diagnostic for dielectric fluids. A reproducible method for applying a protective coating upon the plane electrode to maintain consistent measurements has been developed and demonstrated to be imperative for obtaining PD signatures. Experiments were conducted with hexadecane, which is a relatively pure base fluid. Chemicals commonly associated with ageing processes that occur in dielectric fluids, which include oxidation …

The Relationship Between Breastfeeding And Postpartum Depressive Symptoms In Women From Ecuador, Mexico And Puerto Rico, Jan Weingrad Smith

Doctoral Dissertations

The Relationship Between Breastfeeding and Postpartum Depressive Symptoms in Women

from Ecuador, Mexico, and Puerto Rico

Jan Weingrad Smith, PhD

University of Connecticut, 2012

This study used a secondary data analysis to describe the relationship between breastfeeding and the development of postpartum depressive symptoms in a low-income cohort of women from Ecuador, Mexico, and Puerto Rico in the United States. It also explored the risk of developing postpartum depressive symptoms in low-income women from these communities regardless of their decision to breastfeed. Data were collected between 2006 and 2012 at a Federally Qualified Community Health Center Prenatal Center in New …

Metal Oxide-Based Hybrid Semiconductor Nanowires:Synthesis,Characterization And Chemical Sensing Applications, Wenjie Andy Cai

Doctoral Dissertations

Homogeneous (single material component) nanomaterials generally have limited functional characteristics. Fortunately, with the addition of foreign materials component(s) into (onto) homogeneous nanostructures, potential improvement or multiplication of functions could be achieved. On the other hand, very few functional materials can survive and operate at elevated temperature above 700^oC despite the widespread need in automobiles, industrial reactors, and power plants. Thus it demands new design or discovery of functional nanomaterials with good thermal stability and sustained functions at high temperature. In this study, we look to develop a new class of metal oxide-based hybrid nanowires based on ZnO, SnO …

Advertising Effects On Consumer Processing Of Brand Extensions: Applying The Categorization Model And Framing Theory, Jungsuk Kang

Doctoral Dissertations

This study proposed and tested a conceptual model of consumer processing of brand extensions. The sequential flow of this model is described as follows: (1) consumer exposure to a brand extension spontaneously activates a parent brand category and its extension product category associated with the brand extension; (2) this activation will trigger two types of holistic evaluation, involving consumer assessment of the parent-brand image and product-feature fit between the parent brand category and its extension product category; (3) this holistic evaluation will facilitate either a category-based or a attribute-based judgment of the similarity between the parent brand and its brand …

Noble Metal Based Nanomaterials In The Application Of Direct Alcohol Fuel Cells, Liang Su

Doctoral Dissertations

Fuel cells are envisaged to be a new generation of power sources which convert chemical energy into electrical energy with, theoretically, both economical and environmental benefit. As a subcategory of polymer electrolyte membrane fuel cells, direct alcohol fuel cells exhibit the most pertinent properties in the application of portable electronic devices. As the most important and the most expensive component in DAFCs, electrocatalysts have attracted considerable academic and industrial attention. One of the en route research on fuel cells aims to develop nanomaterials with better catalytic performance and lower cost. Proceeding towards this goal, this dissertation will be focusing on …

Enrollment Decisions Of The Underrepresented: Recruiting And College Choice At Military Institutions, Daniel C. Rose

Doctoral Dissertations

This phenomenological study examined the college enrollment decisions of 20 high school students who participated in the Genesis Invitational program at the United States Coast Guard Academy. The Genesis program was designed to generate interest in postsecondary education among first generation and underrepresented minority students. I used college choice theory as a theoretical framework to analyze and understand the enrollment decisions of Genesis participants considering selective institutions of higher education. Specifically, I conducted semi-structured phone interviews during the mid-choice and post-choice phases of high school seniors’ college choice processes and examined application materials they had submitted to both the Genesis …

Snoop-Forge-Replay Attack On Continuous Verification With Keystrokes, Khandaker Abir Rahman

Doctoral Dissertations

We present a new attack called the snoop-forge-replay attack on the keystroke-based continuous verification systems. We performed the attacks on two levels – 1) feature-level and 2) sample-level.

(1) Feature-level attack targets specific keystroke-based continuous verification method or system. In feature-level attacks, we performed a series of experiments using keystroke data from 50 users who typed approximately 1200 to 2300 keystrokes of free text during three different periods. The experiments consisted of two parts. In the first part, we conducted zero-effort verification experiments with two verifiers ("R" and "S") and obtained Equal Error Rates (EERs) between 10% and 15% under …

Nonlinear Granger Causality And Its Application In Decoding Of Human Reaching Intentions, Mengting Liu

Doctoral Dissertations

Multi-electrode recording is a key technology that allows the brain mechanisms of decision making, cognition, and their breakdown in diseases to be studied from a network perspective. As the hypotheses concerning the role of neural interactions in cognitive paradigms become increasingly more elaborate, the ability to evaluate the direction of neural interactions in neural networks holds the key to distinguishing their functional significance.

Granger Causality (GC) is used to detect the directional influence of signals between multiple locations. To extract the nonlinear directional flow, GC was completed through a nonlinear predictive approach using radial basis functions (RBF). Furthermore, to obtain …

Multi-Scale Characterization Of Nanostructured Sodium Aluminum Hydride, Shathabish Narasegowda

Doctoral Dissertations

Complex metal hydrides are the most promising candidate materials for onboard hydrogen storage. The practicality of this class of materials is counter-poised on three critical attributes: reversible hydrogen storage capacity, high hydrogen uptake/release kinetics, and favorable hydrogen uptake/release thermodynamics. While a majority of modern metallic hydrides that are being considered are those that meet the criteria of high theoretical storage capacity, the challenges lie in addressing poor kinetics, thermodynamics, and reversibility. One emerging strategy to resolve these issues is via nanostructuring or nano-confinement of complex hydrides. By down-sizing and scaffolding them to retain their nano-dimensions, these materials are expected to …

The Role Of Face-To-Face Interactions In The Success Of Virtual Project Teams, Lawrence Raymond Blenke

Doctoral Dissertations

"This dissertation examines the importance of in-person Face-To-Face (FTF) interactions in virtual engineering development projects. The basis for this investigation will be the hypothesis that FTF interactions increase the effectiveness, quality of communication, and the trust between participants beyond that achieved with purely computer mediated communication. Through a combination of a literature review and empirical research, this dissertation addresses the following questions: * How important is FTF interaction in virtual development work? * Do various functional areas and age groups rate the importance of FTF interactions differently? * How does FTF interaction affect the levels of trust and communication within …

A Comparison Of American And Asian Automakers' Vehicles In Quality, Reliability, And Safety, Ozge Senoz

Doctoral Dissertations

"Consumer Reports (CR) and J.D. Power and Associates (JDP) are two widely-known agencies that gather data on automobile quality and prepare reports on the data gathered that are related to various aspects of automobiles for different models for each manufacturer. This research has two overarching goals: The first is to determine if there are any clear differences in reliability, between the Japanese and U.S. auto-makers. The second is to determine if there is consistency between JDP and CR in the reliability ratings of vehicles. In order to attain these goals, this dissertation starts with the evaluation of these two major …

Writing Assessment's "Debilitating Inheritance": Behaviorism's Dismissal Of Experience, Maja Joiwind Wilson

Doctoral Dissertations

In this project, I examine the legacy of behaviorism's dismissal of experience on contemporary writing assessment theory and practice within the field of composition studies. I use an archival study of John B. Watson's letters to Robert Mearns Yerkes to establish behaviorism's systematic denial of experience and its related constructs: mind, consciousness, thought, emotions, purpose, and meaning. I trace this denial through the efficiency movement's effects on education and educational measurement in the early 20th century and the establishment of the behaviorist infrastructure of assessment---an infrastructure that contributed; paradoxically, to the early focus in composition studies on experience. I analyze …

Molecular Self-Assembly Of Functionalized Pentacenes And Fullerenes On Metal Surfaces By Stm And Dft Investigations, Jun Wang

Doctoral Dissertations

Enormous efforts have been made in seeking alternative pathways to more effectively use solar energy. Organic solar cells, composed essentially of carbon-based organic molecular materials, have attracted considerable scientific and industrial attentions because of their economic and environmental benefits. It is advantageous to have the comprehension of the molecular structures and interfacial morphologies for these active molecular materials on substrates in the nanoscale regime.

Controlling the heterostructures of the molecular donor and acceptor materials is essential to overcoming the efficiency bottleneck in organic photovoltaics. Molecular self-assembly on patterned substrates provides a bottom-up approach to create well-controlled molecular heterojunctions and a …

Approaches To Modeling Pathogen And Natural Organic Matter Removals In Slow-Rate Biofilters, Jeffrey Dale Senders

Doctoral Dissertations

There are limited expressions capable of estimating removals in one of the world's oldest and most sustainable water treatment systems: slow-rate biofilters. This research addresses the problem by deriving semi-empirical models that predict pathogen and natural organic matter removals within these natural and engineered sand filters. The more complex pathogen model, or phenomenological colloidal filtration theory (pCFT), applies the 1937 Iwasaki solution to New England pilot scale E. coli observations. The derived pCFT was then calibrated through a series of experimental bench scale phases. Further pCFT validation came by way of a seamless application to multiple microorganisms. Viruses (MS2 as …

Characterization Of Low-Temperature Properties Of Plant-Produced Rap Mixtures In The Northeast, Marcelo S. Medeiros Junior.

Doctoral Dissertations

The dissertation outlined herein results from a Federal Highway Administration sponsored project intended to investigate the impacts of high percentages of RAP material in the performance of pavements under cold climate conditions. It is comprised of two main sections that were incorporated into the body of this dissertation as Part I and Part II. In Part I a reduced testing framework for analysis of HMA mixes was proposed to replace the IDT creep compliance and strength testing by dynamic modulus and fatigue tests performed on an AMPT device. A continuum damage model that incorporates the nonlinear constitutive behavior of the …

Engineering Lipases And Solvents For Trans/-Esterification Of Used Vegetable Oils, Michael Dore Gagnon

Doctoral Dissertations

Diminishing petroleum reserves and increasing environmental awareness has led to an urgent need to develop alternative fuels, such as biodiesel. However, the conventional method to produce biodiesel uses environmentally harmful chemical catalysts. A relatively new development in the production of biodiesel is through enzymatic trans/- esterification with a lipase catalyst. Despite several advantages, there are a few technical and economical obstacles that limit this process: (1) immiscibility of the hydrophilic methanol and hydrophobic triglyceride which results in the formation of an interface leading to mass transfer resistance, (2) insufficient availability of large quantities of inexpensive lipase suitable for catalysis, and …

Characterization Of The Expression Profile Of Polyamine Biosynthetic Genes (Spermidine Synthase) And Polyamine Metabolic Regulation In Arabidopsis, Lin Shao

Doctoral Dissertations

Polyamines are ubiquitously distributed cationic compounds, which play important roles in numerous cellular functions in plants. This study was aimed at elaborating the regulation of polyamine biosynthetic gene expression and polyamine metabolism. The organ/tissue specific expression patterns of two genes encoding the polyamine biosynthetic enzyme spermidine synthase ( AtSPDS1 and AtSPDS2) were studied in Arabidopsis at different developmental stages using promoter::reporter approach. The two homologues showed similar ubiquitous expression with subtle differences being observed in certain tissues (e.g. root, siliques, and embryos). Neither transgenic manipulation by over-expression of AtSPDSI alone nor its concomitant expression with genes encoding other biosynthetic enzymes …

Light Hadron Properties From Lattice Qcd, Parikshit M. Junnarkar

Doctoral Dissertations

The subject of this thesis is mainly concerned with dynamics of light quarks. The question that will be attempted to answer is, What is the quark mass dependence of low lying hadrons ? In particular, this work will focus on the quark mass dependence of mesons and baryons with the tools of lattice calculations and effective field theories.

The two and three flavor effective field theories are applied to pions and kaons respectively to study the quark mass dependence of their masses and decay constants. In addition, the phenomenologically interesting ƒ K / ƒpi, is analysed in three flavor theory. …

Pulsating Aurora: Source Region & Morphology, Allison Jaynes

Doctoral Dissertations

Pulsating aurora, a common phenomenon in the polar night sky, offers a unique opportunity to study the precipitating particle populations responsible for this subtle yet fascinating display of lights. The conjecture that the source of these electrons originates near the equator, made decades ago, has now been confirmed using in-situ measurements. In this thesis, we present these results that compare the frequencies of equatorial electron flux pulsations and pulsating aurora luminosity fluctuations at the ionospheric footprint. We use simultaneous satellite-based data from GOES 13 and ground-based data from the THEMIS allsky imager array to show that there is a direct …

The Effects Of Biotic And Abiotic Factors On Byssogenesis, Growth And Movement Patterns Of The Blue Mussel, Mytilus Edulis, Yvette Louise Garner

Doctoral Dissertations

Blue mussels create extensive aggregations on intertidal and low subtidal shores in the Gulf of Maine, in which they modify habitat, trap sediments and create microclimates for many organisms. Mussels are an important aquaculture species worldwide, and play a major part of the economy of New England. Blue mussels produce collagenous byssal threads to anchor themselves to the substrate on wave swept shores. Byssogenesis, growth and movement abilities of mussels are influenced by a host of biotic and abiotic factors. In this dissertation I quantified byssogenesis and growth of the blue mussel, Mytilus edulis, affected by wave exposure, temperature, and …

Extreme Value Theory: Applications To Estimation Of Stochastic Traffic Capacity And Statistical Downscaling Of Precipitation Extremes, Eric Matthew Laflamme

Doctoral Dissertations

This work explores two applications of extreme value analysis. First, we apply EV techniques to traffic stream data to develop an accurate distribution of capacity. Data were collected by the NHDOT along Interstate I93, and two adjacent locations in Salem, NH were examined. Daily flow maxima were used to estimate capacity, and data not associated with daily breakdown were deemed censored values. Under this definition, capacity values are approximated by the generalized extreme value (GEV) distribution for block maxima. To address small sample sizes and the presence of censoring, a Bayesian framework using semi-informative priors was implemented. A simple cross …

Bacterial Biodegradation Of Soluble Crude Oil Hydrocarbons And The Influence Of Protists In Simulated Arctic Seawater And Sea Ice, Heather Ballestero

Doctoral Dissertations

With expected increases in vessel traffic, drilling, and exploration for petroleum and natural gas, the potential for an Arctic oil spill is heightened, yet knowledge of contaminant fate and behavior is limited in this environment. With challenging conditions in the Arctic and limited equipment caches, response will be extremely difficult. In freezing conditions, oil may become encapsulated in ice. Understanding biodegradation potential in this environment can dictate response options for spills that occur in Arctic marine waters. The influence of protists on bacterial biodegradation of water accommodated fractions (WAF) of petroleum hydrocarbons is unknown, yet important because it could enhance …

Examining Social Climate And Youth Social Goals On Extended Wilderness Courses: A Path Toward Improving Participant Experiences, Benjamin J. Mirkin

Doctoral Dissertations

This dissertation examined participants' expectations of the social climate on extended wilderness courses, how students' actually experienced the social climate during their course, and how these expectations, perceptions and the influence of environmental characteristics, impacted their goals for peer interactions. Pre and posttest surveys were used to assess students' expectations and perceptions of their experience and multi level modeling was used to better understand the relationship of social climate to peer interaction. The research was undertaken to improve the practical and theoretical understanding of organizations' and leaders' ability to facilitate a social climate that promotes adaptive forms of social motivation. …

I The Tandem Chain Extension-Acylation Reaction Ii Synthesis Of Papyracillic Acid A: Application Of The Tandem Homologation-Acylation Reaction Iii Synthesis Of Tetrahydrofuran-Based Peptidomimetics, Carley Meredith Spencer

Doctoral Dissertations

A zinc-mediated tandem chain extension-acylation reaction was successfully developed. This reaction was optimized with the use of beta-keto esters, amides, and imides as well as a variety of acylating agents. The tandem homologation-acylation reaction was successfully applied towards the total synthesis of papyracillic acid A.

Use of a tandem chain extension-aldol reaction, followed by a reductive cyclization, allowed for the synthesis of tetrahydrofuran-based peptidomimetics. A variety of amino acid derived beta-keto imides and aldehydes were used during the initial tandem homologation-aldol reaction. High diastereocontrol was achieved during reductive cyclization when a cis relationship was present between the substituents on the …

Utilization Of Copper Alloys For Marine Applications, Andrew Drach

Doctoral Dissertations

Utilization of copper alloy components in systems deployed in marine environment presents potential improvements by reducing maintenance costs, prolonging service life, and increasing reliability. However, integration of these materials faces technological challenges, which are discussed and addressed in this work, including characterization of material performance in seawater environment, hydrodynamics of copper alloy components, and design procedures for systems with copper alloys.

To characterize the hydrodynamic behavior of copper alloy nets, mesh geometry of the major types of copper nets currently used in the marine aquaculture are analyzed and formulae for the solidity and strand length are proposed. Experimental studies of …

Multiscale Numerical Modeling And Characterization Of Carbon/Carbon Composites, Borys Drach

Doctoral Dissertations

Carbon/carbon composite is a high-performance material with a unique set of physical and thermo-mechanical properties making it irreplaceable for severe environment aerospace applications. Its complex hierarchical microstructure presents materials scientists and engineers with substantial modeling challenges when it comes to predicting material's behavior under various loading conditions. My research has been focused on characterization, mutliscale modeling and mechanical testing of this composite. A set of new elasticity solutions for the carbon fiber surrounded by multiple layers of pyrolytic carbon represented as a multicoated cylinder is presented on the microscale. On the mesoscale, deterministic and statistical approaches to evaluation of contributions …