Digital Commons Network^™

"This Wilderness World": The Evolution Of A New England Farm Town, 1820--1840, Mary Babson Fuhrer

Doctoral Dissertations

This dissertation uses the extraordinary conflict that roiled one rural town in central Massachusetts during the second quarter of the nineteenth century as a lens through which to observe communal relationships in transition. Using the Amish as a model, the dissertation identifies traditional communal social organization as agrarian, patriarchal, communal, homogeneous, localistic, and consensual -- as well as closed, conformist, and suspicious of difference and innovation. The dissertation argues that conflict arose in Boylston during the 1820s and '30s as these traditional relationships gradually gave way to more modern ways of belonging, associating, and envisioning one's place in the wider …

Teaching, Activism, And The Purposes Of Education: Toward An Integrated Vision Of Teachers' Work, Carina E. Self

Doctoral Dissertations

The purpose of this study was to consider the political dimensions of teachers' work through a conceptual comparison to the work of social activists. The author developed a four-part analysis of the work of activists through a reading of the social movement literature and compared that analysis to the work of teachers according to four contemporary approaches to teachers' work (neo-conservative, caring, contemporary liberal, and critical theory). The result was an integrated vision of teachers' work that brings together teachers' daily practices and their educational commitments around four dimensions of teachers work: social critique, identity formation/negotiation, affiliation, and institutional change. …

Land Development In Massachusetts: Its Effect On The Environment Within Essex And Middlesex Counties From 1990 To 2007, Peter Sean Tardie

Doctoral Dissertations

Since the 1970's urban centers in and surrounding Essex and Middlesex Counties in Massachusetts have expanded and proliferated into adjacent communities. This expansion has led to the conversion of land for housing, businesses, schools, recreation, and parks, placing significant strain on existing land cover, land use, and available natural resources. Mounting growth pressures and a reduction of undeveloped land have raised serious concerns as cropland and forest fragmentation, wetland destruction, protected open-space infringement, pollution, and systematic losses of rural conditions have become obvious. To monitor development, the post-classification change detection method was applied to Landsat Thematic Mapper (TM) satellite data …

Human-Human Multi-Threaded Spoken Dialogs In The Presence Of Driving, Oleksandr Shyrokov

Doctoral Dissertations

The problem addressed in this research is that engineers looking for interface designs do not have enough data about the interaction between multi-threaded dialogs and manual-visual tasks. Our goal was to investigate this interaction. We proposed to analyze how humans handle multi-threaded dialogs while engaged in a manual-visual task. More specifically, we looked at the interaction between performance on two spoken tasks and driving. The novelty of this dissertation is in its focus on the intersection between a manual-visual task and a multi-threaded speech communication between two humans.

We proposed an experiment setup that is suitable for investigating multi-threaded spoken …

Integrated, Multi-Attribute Decision Support System For The Evaluation Of Underground Utility Construction Methods, John C. Matthews

Doctoral Dissertations

The dissertation research work described herein is comprised of three primary objectives: (1) the development of a rehabilitation method selection software (TAG-R) for the National Association of Sewer Service Companies (NASSCO) and its subsequent validation and combination with TAG (a sister decision support system (DSS) software developed by the author in an earlier work); (2) the development of a social cost calculator (SCC) and its validation; and (3) the development of a proposed framework for multi-segment optimization for construction methods selection using the tools developed in the first two objectives as well as additional project related data.

The selection of …

Application Of Quality Engineering To Investment Portfolio Selection And Optimization, Vivek Kulinchandra Jikar

Doctoral Dissertations

"The Taguchi System of Quality Engineering (TSQE) is a widely accepted philosophy and set of tools and techniques to rapidly design and manufacture high quality, low cost products and services. It is heavily focused on creating stable system designs that allow a product or system to perform as desired by customers in the environment of their choice. This research demonstrates the power of the TSQE to manage an investment portfolio. In particular, it uses the concept of design stability to select investments and optimize portfolios. It proposes a new design stability-based investment screening metric and discusses its application. Further, this …

Effects Of Optimized And Sub-Optimum Two Degree Of Freedom Lining Tolerances On Modeled Inlet Acoustic Attenuation And Normal Incidence Impedance Measurement At Elevated Temperatures, David R. Burd

Doctoral Dissertations

"This work first investigates the effect of manufacturing tolerances on realized attenuation for two degree-of-freedom linings with the use of lining models and finite element duct propagation codes. Acoustic linings were created for two turbofan engines that optimize attenuation at takeoff/sideline and approach conditions. Lining physical and geometric parameters were set, which best meet the optimum impedance requirements at two target frequencies. Similar linings were created to investigate sub-optimum designs. Variations of these parameters representing realistic manufacturing tolerances were used to systematically examine the effect on installed impedance and predicted attenuation. Attenuation at sideline and approach conditions was found to …

Experimental And Computational Investigations Of Hydrogen Safety, Dispersion And Combustion For Transportation Applications, Shravan K. Vudumu

Doctoral Dissertations

"Hydrogen is an energy carrier that can be produced from a variety of sources, offering one of the viable solutions to the increasing demands for clean and sustainable energy. Compared to the conventional fuels, hydrogen has distinct properties that need to be properly accounted for during its safer storage and delivery as well as more efficient and cleaner utilization. The broader objective of this study is to contribute to the scientific knowledge necessary to overcome key technical barriers to the widespread implementation of hydrogen in transportation applications. Specifically, lower flammability limit of hydrogen is first measured with an enhanced experimental …

Ground Penetrating Radar Investigations In Upper Kama Potash Mines, Oleg N. Kovin

Doctoral Dissertations

"An understanding of the structure and state of the rock mass surrounding underground openings in the potash mines is critically important for safe mining, planning the methods of extraction of an orebody, and preventing the influx of ground water. Continuous common offset ground penetrating radar (GPR) data were acquired in the potash mine operated by the Joint Stock Company (JSC) "Silvinit" (Russia) as part of an investigation of both pre-existing fractures exposed by mine workings and other anomalous geological structures. During the course of GPR investigation, the electrical properties of salt-bearing units were determined, site-specific data acquisition techniques and object-oriented …

Solid Oxide Fuel Cell Electrode Characterization And Improvement For Fuel Flexibility And Supplemental Power Production, Isaiah D. Kellogg

Doctoral Dissertations

"Solid oxide fuel cells (SOFC) were fabricated and the electrodes tested for their individual catalytic effectiveness in various fuels by exposing each electrode to mixed gas while the opposite electrode was exposed to its respective pure gas. Mixed hydrogen and oxygen gas was successfully utilized as fuel in a single chamber SOFC (SC-SOFC). The conditions at which the porous nickel-yttria-stabilized zirconia (Ni-YSZ) cermet anode performed well did not significantly overlap the conditions at which the La₀.₈Sr₀.₂Fe₀.₈Co₀.₂ oxide (LSCF) cathode performed well, but there was significant catalytic activity at both electrodes which increased the open circuit voltage (OCV) beyond that predicted …

Analysis Of Laminated Architectural Glazing Subjected To Combined Wind And Debris Impact Loading, Mahesh Shibarooru Shetty

Doctoral Dissertations

"Laminated glazing has been a popular form of window glazing in recent years and is found to be effective during extreme weather conditions like hurricane. Laminated glass is composed of two glass layers with a polymer as an interlayer. The main objective of this work involves studying the stress response, failure and damage analysis of rectangular laminated architectural glazing against combined wind and windborne debris impact. Here both small-hard (like roof gravel) and large-soft (like timber) windborne debris are considered. The stress response of the rectangular laminated architectural glazing was modeled using the finite element code ABAQUS. The effect of …

The Functionalization Of Single Wall Carbon Nanotubes For Bioapplications, Pu Zhang

Doctoral Dissertations

"In the past few years, the functionalization of carbon nanotubes has received considerable attention due to their extraordinary mechanical, electrical, optical and thermal properties. Using single wall carbon nanotube as a platform in bioanalytical and biomedical applications has also been extensively studied. This dissertation consists of four papers. In the first paper, various methods to functionalize single wall carbon nanotubes with immobilized enzyme for bioanalytical application were investigated. It was found that the covalent functionalization method was not an ideal methodology for enzyme addition neither in terms of enzyme loading amount nor activity retention compared to other methods. Use of …

Emerging Technology Supply Chain Model For Additive Manufacturing, David M. Dietrich

Doctoral Dissertations

"This research concerns developing an emerging manufacturing technology, additive manufacturing (AM), into a mature and flexible, cost-effective supply chain for aerospace production. The field of additive manufacturing is an approach to low volume manufacturing of plastic or metal parts using three dimensional Computer Aided Design data. As an emerging technology, AM's supply chain is not established compared to conventional aerospace manufacturing technologies, such as injection molding or composite manufacturing. Technical and business challenges limit the robustness of the additive manufacturing system for aerospace applications. The overall intent of this research is to: first, provide an introduction to two main polymer …

Dynamic Reconfiguration And Control Of Smart Power Systems, Pinaki Mitra

Doctoral Dissertations

"To address the increasing demand and complexity, modern power systems need intelligence at almost all levels which can transform them into 'smart' power systems. The term 'smart power systems' not only refers to the terrestrial power systems with a significant penetration of distributed energy resources and energy storage such as plug-in electric vehicle parking lots (SmartParks), but also includes other isolated power systems, such as the power systems of naval electric ships. The research presented in this dissertation contributes to the dynamic reconfiguration and control of both terrestrial and ship power system with the application of computational intelligence methods.

In …

Advanced Dynamic Response Improvement Methods For Dc-Dc Power Electronic Converters, Lisheng Shi

Doctoral Dissertations

"Dc-dc power electronic converters supplying electric power to digital processors, data centers, and telecommunication systems are required to exhibit a fast dynamic response in response to their instantaneous electric load variations. This requirement is becoming more and more stringent as the operating voltage of such loads is continuously reducing. This voltage level reduction has reached a point where conventional control approaches can barely meet the dynamic response demanded by such loads. In order to overcome this issue, several approaches focusing on the dynamic response improvement for dc-dc converters have been proposed in the literature. Unfortunately, most of them have at …

The Effects Of Using Screencasting As A Multimedia Pre-Training Tool To Manage The Intrinsic Cognitive Load Of Chemical Equilibrium Instruction For Advanced High School Chemistry Students, Ramsey Musallam

Doctoral Dissertations

NA

Adaptive Resource Allocation For Cognitive Wireless Ad Hoc Networks, Behdis Eslamnour

Doctoral Dissertations

"Widespread use of resource constrained wireless ad hoc networks requires careful management of the network resources in order to maximize the utilization. In cognitive wireless networks, resources such as spectrum, energy, communication links/paths, time, space, modulation scheme, have to be managed to maintain quality of service (QoS). Therefore in the first paper, a distributed dynamic channel allocation scheme is proposed for multi-channel wireless ad hoc networks with single-radio nodes. The proposed learning scheme adapts the probabilities of selecting each channel as a function of the error in the performance index at each step.

Due to frequent changes in topology and …

Intelligent Power System Operation In An Uncertain Environment, Yusuf Yare

Doctoral Dissertations

"This dissertation presents some challenging problems in power system operations. The efficacy of a heuristic method, namely, modified discrete particle swarm optimization (MDPSO) algorithm is illustrated and compared with other methods by solving the reliability based generator maintenance scheduling (GMS) optimization problem of a practical hydrothermal power system. The concept of multiple swarms is incorporated into the MDPSO algorithm to form a robust multiple swarms-modified particle swarm optimization (MS-MDPSO) algorithm and applied to solving the GMS problem on two power systems. Heuristic methods are proposed to circumvent the problems of imposed non-smooth assumptions common with the classical approaches in solving …

Fluid Flow Related Phenomena And Inclusion Motion In Continuous Casting Strands, Yufeng Wang

Doctoral Dissertations

"To improve the efficiency of the continuous casting process and the quality of its products, this dissertation mainly investigated fluid flow related phenomena and inclusion motion in continuous casting. Mathematical simulation was performed for this purpose. Both a slab caster and a billet caster were investigated. In the study of the slab caster, the application of electromagnetic brake field on the slab mold was evaluated. The results indicated that the magnetic force decelerated the high speed steel jet, stabilized the top fluctuation, and prevented the bias flow inside the mold. The other study of this slab caster involved the fluid …

Nmr Investigations Of Biomass-To-Fuel Conversions By Hydrothermal Processes, Wenjia Zhang

Doctoral Dissertations

"Biofuels have gained significant attention as the most promising alternative energy and fuel supply for the near future because of two dominant reasons: first, biofuels are environmentally friendly; and second, they afford a sustainable technology. Biofuels can be synthesized from biomass by several different processes, among which, hydrothermal conversion is considered to be more energy efficient. However, scientific efforts to improve hydrothermal biomass-to-fuel (HT-BTF) conversion efficiencies are severely limited because little is known about the salient reaction mechanisms and intermediates. This study is aimed at a better understanding of the hydrothermal biomass degradation kinetics by advanced NMR spectroscopy and, accordingly, …

Optimal Excitation Controllers, And Location And Sizing Of Energy Storage For All-Electric Ship Power System, Chuan Yan

Doctoral Dissertations

"The Navy's future all-electric ship power system is based on the integrated power system (IPS) architecture consisting of power generation, propulsion systems, hydrodynamics, and DC zonal electric distribution system (DC-ZEDS). To improve the power quality, optimal excitation systems, and optimal location and sizing of energy storage modules (ESMs) are studied. In this dissertation, clonal selection algorithm (CSA) based controller design is firstly introduced. CSA based controller design shows better exploitation ability with relatively long search time when compared to a particle swarm optimization (PSO) based design. Furthermore, 'optimal' small population PSO (SPPSO) based excitation controller is introduced. Parameter sensitivity analysis …

Deadlock Detection And Dihomotopic Reduction Via Progress Shell Decomposition, David Andrew Cape

Doctoral Dissertations

"Deadlock detection for concurrent programs has traditionally been accomplished by symbolic methods or by search of a state transition system. This work examines an approach that uses geometric semantics involving the topological notion of dihomotopy to partition the state space into components, followed by an exhaustive search of the reduced state space. Prior work partitioned the state-space inductively; however, this work shows that a technique motivated by recursion further reduces the size of the state transition system. The reduced state space results in asymptotic improvements in overall runtime for verification. Thus, with efficient partitioning, more efficient deadlock detection and eventually …

Effect Of Structure And Plasticizer On The Glass Transition Of Adsorbed Polymer, Boonta Hetayothin

Doctoral Dissertations

"The effect of molecular mass on adsorbed poly(methyl methacrylate) (PMMA) on silica was determined using temperature-modulated differential scanning calorimetry (TMDSC). A two-component model, based on loosely-bound polymer (glass transition temperature, T_g, similar to that of bulk) and tightly-bound polymer (T_g higher than that of bulk) was used to interpret the thermograms. Similar amounts of tightly-bound polymer were found for 450 and 85 kDa PMMA (0.78 mg/m²), while the 32 kDa sample had a smaller amount (0.48mg/m²). A comparison of adsorbed PMMA, poly(vinyl acetate) (PVAc), and poly(methyl acrylate) (PMA) on silica was made using the same technique. The …

Computational Methods For The Discovery And Analysis Of Genes And Other Functional Dna Sequences, Cyriac Kandoth

Doctoral Dissertations

"The need for automating genome analysis is a result of the tremendous amount of genomic data. As of today, a high-throughput DNA sequencing machine can run millions of sequencing reactions in parallel, and it is becoming faster and cheaper to sequence the entire genome of an organism. Public databases containing genomic data are growing exponentially, and hence the rise in demand for intuitive automated methods of DNA analysis and subsequent gene identification. However, the complexity of gene organization makes automation a challenging task, and smart algorithm design and parallelization are necessary to perform accurate analyses in reasonable amounts of time. …

Protein Secondary Structure Prediction Using Blast And Relaxed Threshold Rule Induction From Coverings, Leong Lee

Doctoral Dissertations

"Protein structure prediction has always been an important research area in bioinformatics and biochemistry. Despite the recent breakthrough of combining multiple sequence alignment information and artificial intelligence algorithms to predict protein secondary structure, the Q₃ accuracy of various computational prediction methods rarely has exceeded 75%; this status has changed little since 2003 when Rost stated that "the currently best methods reach a level around 77% three-state per-residue accuracy." The application of artificial neural network methods to this problem is revolutionary in the sense that those techniques employ the homologues of proteins for training and prediction. In this dissertation, a different …

Synthesis And Characterization Of Conducting Polymer Nanostructures And Their Application In Sensors, Zhe-Fei Li

Doctoral Dissertations

"A one-step synthesis technique has been used to fabricate sensors by growing polyaniline nanofibers and polyaniline/metal nanocomposites in the active area of an interdigitated electrode array. Polyaniline nanofiber sensors can be fabricated by irradiating an aqueous precursor solution containing aniline, HCl, a metal salt, and ammonium persulfate (APS) with a high pressure Hg lamp. The sensors are ready for operation after polymerization is complete, and no additional processing steps are necessary. These sensors showed faster and more intensity response to various organic vapors than conventional bulk polyaniline sensors due to their larger surface area. A chemisorption model and a diffusion …

Characterization Of Diamond Thin Films And Related Materials, Travis K. Mckindra

Doctoral Dissertations

"Thin carbon films including sputtered deposited graphite and CO₂ laser-assisted combustion-flame deposited graphite and diamond thin films were characterized using optical and electron microscopy, X-ray diffraction and micro-Raman spectroscopy. Amorphous carbon thin films were deposited by DC magnetron sputtering using Ar/O₂ gases. The film morphology changed with the oxygen content. The deposition rate decreased as the amount of oxygen increased due to oxygen reacting with the growing film. The use of oxygen in the working gas enhanced the crystalline nature of the films. Graphite was deposited on WC substrates by a CO₂ laser-assisted O₂/C₂H₂ combustion-flame method. Two distinct microstructural areas …

Chemical Bath Deposition And Electrodeposition Of Epitaxial Semiconductor Materials For Application In Photovoltaic Devices, Guojun Mu

Doctoral Dissertations

"This dissertation investigates the chemical bath deposition of zinc oxide and electrodeposition of cuprous iodide on polycrystalline and single crystal substrates. Paper I describes the chemical bath deposition and characterization of titled epitaxial zinc oxide nanospears on Si(001) single crystal substrate. In Paper II, the chemical bath deposition of zinc oxide nanospears from highly alkaline solutions is discussed in detail, including a thermodynamic calculation of saturation and speciation of Zn(II) in aqueous solution, and a kinetic study of the deposition process. In this paper the epitaxial zinc oxide is reported grown on Au(100), (110), and (111) single crystals. Paper III …

Sensor Data-Based Decision Making, Ahmet Soylemezoglu

Doctoral Dissertations

"Increasing globalization and growing industrial system complexity has amplified the interest in the use of information provided by sensors as a means of improving overall manufacturing system performance and maintainability. However, utilization of sensors can only be effective if the real-time data can be integrated into the necessary business processes, such as production planning, scheduling and execution systems. This integration requires the development of intelligent decision making models that can effectively process the sensor data into information and suggest appropriate actions. To be able to improve the performance of a system, the health of the system also needs to be …

Phase Equilibria In Iron Phosphate System, Liying Zhang

Doctoral Dissertations

"The main objectives of this research were to synthesize iron phosphate compounds, study phase equilibria in the iron phosphate system, focusing on the glass forming area, and investigate glass formability and properties based on the liquidus regions. Twelve iron phosphate compounds were successfully prepared and studied in terms of liquidus temperature or decomposition behavior. The liquidus surface of the Fe₃PO₇- Fe(PO₃)₃ system was re-determined and found to be significantly different from that originally presented by Wentrup in 1935. Eutectic points exist at 58.0 mole% Fe₂O₃ (1070⁰C), 42.7 mole% Fe₂O₃ (925°C), and 37.0 mole% Fe₂O₃ (907°C). The latter two eutectic points …