Neutron scattering studies of the RENi 2B 2C (RE = Lu, Y, Ho, Er): Lattice dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bullock, Max

1998-02-23

The first chapter gives a brief overview of the system discussed in this dissertation. Chapters 2-5 and Appendix B of this dissertation consist of papers that are published, or have been submitted, which show experimental data regarding the phonon softening of LuNi 2B 2C. These papers have been removed and processed separately. Chapter 6 will contain a summary of the conclusions up to date. Appendix A will consist of a brief derivation of χ(q) which is talked about in the introduction of the dissertation. Appendix B will contain a Born-von Karman model fit to the experimental LuNi 2B 2C datamore » and a comparison with experimental data. Appendix C will contain a brief summary of the work done on LuNi 2B 2C as well as a complete listing of experimental data taken on the crystals which may be needed later for theoretical models of this system. Appendix D will outline a brief introduction covering some of the field theory used in the theoretical work for this thesis.« less

An Analysis of Research Methods and Statistical Techniques Used by Doctoral Dissertation at the Education Sciences in Turkey

ERIC Educational Resources Information Center

Karadag, Engin

2010-01-01

To assess research methods and analysis of statistical techniques employed by educational researchers, this study surveyed unpublished doctoral dissertation from 2003 to 2007. Frequently used research methods consisted of experimental research; a survey; a correlational study; and a case study. Descriptive statistics, t-test, ANOVA, factor…

Research on Novel Algorithms for Smart Grid Reliability Assessment and Economic Dispatch

NASA Astrophysics Data System (ADS)

Luo, Wenjin

In this dissertation, several studies of electric power system reliability and economy assessment methods are presented. To be more precise, several algorithms in evaluating power system reliability and economy are studied. Furthermore, two novel algorithms are applied to this field and their simulation results are compared with conventional results. As the electrical power system develops towards extra high voltage, remote distance, large capacity and regional networking, the application of a number of new technique equipments and the electric market system have be gradually established, and the results caused by power cut has become more and more serious. The electrical power system needs the highest possible reliability due to its complication and security. In this dissertation the Boolean logic Driven Markov Process (BDMP) method is studied and applied to evaluate power system reliability. This approach has several benefits. It allows complex dynamic models to be defined, while maintaining its easy readability as conventional methods. This method has been applied to evaluate IEEE reliability test system. The simulation results obtained are close to IEEE experimental data which means that it could be used for future study of the system reliability. Besides reliability, modern power system is expected to be more economic. This dissertation presents a novel evolutionary algorithm named as quantum evolutionary membrane algorithm (QEPS), which combines the concept and theory of quantum-inspired evolutionary algorithm and membrane computation, to solve the economic dispatch problem in renewable power system with on land and offshore wind farms. The case derived from real data is used for simulation tests. Another conventional evolutionary algorithm is also used to solve the same problem for comparison. The experimental results show that the proposed method is quick and accurate to obtain the optimal solution which is the minimum cost for electricity supplied by wind farm system.

Common Methodology Mistakes in Dissertations: Improving Dissertation Quality.

ERIC Educational Resources Information Center

Thompson, Bruce

Dissertations are the cumulative, tangible "best evidence" of interests of doctoral faculty and students in serious and incisive scholarship. Thus, dissertations are thoroughly studied by the program review teams periodically hired by boards of higher education in most states. The present paper explores seven errors in quantitative…

Biphoton optics

NASA Astrophysics Data System (ADS)

Strekalov, Dmitry Vladimirovich

1997-10-01

The subject of this dissertation is the study of the two- photon entanglement. This phenomenon has been paid a great deal of attention since 1935, when A. Einstein, B. Podolsky and N. Rosen asked their famous question, 'Can quantum-mechanical description of physical reality be considered complete?' An entangled system behavior is inconsistent with many classical concepts. Therefore, the understanding of two-photon entanglement is important for the foundations of quantum theory. A two-photon entangled sate represents a two-photon, or a biphoton, rather than two photons. The concept of biphoton as a single nonlocal quantum object is fundamentally different from the concept of a photon pair, as has been experimentally demonstrated in the present dissertation. Two-photon entanglement gives rise to unusual 'ghost' interference and diffraction, nonlocal geometrical phase, and other quantum phenomena originally studied in the present dissertation. The variety of available results calls for bringing them into a general system which we call Biphoton Optics. This is the main goal of this dissertation. Biphoton optics operate with two-photon wave packets, or with an equivalent concept of advanced wave. We show that in the framework of the advanced wave concept two-photon phenomena can be effectively described in terms of classical optics. Therefore the biphoton optics has the same structure as the classical optics. It includes two- photon geometrical optics, dispersion and frequency beating, polarization effects, interference, diffraction, and geometrical phase. All these two-photon effects are represented by experiments included in this dissertation. Our approach does not make two-photon quantum effects 'classical', however. It should be understood that the advanced wave model operates with counter-propagation in time which does not correspond to any real physical process. Therefore it is just a model, but it is clearly a great advantage to have such a model that is both simple and powerful, in terms of its ability to describe the known results and accurately predict the new ones. Therefore an important step is made in understanding and describing of the quantum phenomena of two-photon entanglement.

Narrative synthesis of equine-assisted psychotherapy literature: Current knowledge and future research directions.

PubMed

Lee, Ping-Tzu; Dakin, Emily; McLure, Merinda

2016-05-01

Equine-assisted psychotherapy (EAP) is an innovative emerging approach to mental health treatment. This narrative synthesis explores the current state of knowledge and areas for future research in EAP. Specifically reviewed are qualitative and quantitative empirical studies, including both articles published in peer-reviewed journals and research presented in theses and dissertations. We selected 24 studies for final inclusion in this study, dating between 2005 and 2013, and including the first EAP empirical research completed in 2005. Four of these studies are peer-reviewed journal articles, while 20 are master's theses or doctoral dissertations. The reviewed qualitative research provides initial evidence for the value of EAP for enhancing adolescents' communication and relationship skills. The reviewed experimental and quasi-experimental research provides initial evidence for the value of EAP for enhancing children's and adolescents' emotional, social and behavioural functioning. Yet, conclusions about the effectiveness of EAP must still be considered preliminary due to various methodological limitations in the reviewed research. The narrative review describes these methodological limitations and concludes with recommendations for future research. © 2015 John Wiley & Sons Ltd.

Hybrid power system intelligent operation and protection involving distributed architectures and pulsed loads

NASA Astrophysics Data System (ADS)

Mohamed, Ahmed

Efficient and reliable techniques for power delivery and utilization are needed to account for the increased penetration of renewable energy sources in electric power systems. Such methods are also required for current and future demands of plug-in electric vehicles and high-power electronic loads. Distributed control and optimal power network architectures will lead to viable solutions to the energy management issue with high level of reliability and security. This dissertation is aimed at developing and verifying new techniques for distributed control by deploying DC microgrids, involving distributed renewable generation and energy storage, through the operating AC power system. To achieve the findings of this dissertation, an energy system architecture was developed involving AC and DC networks, both with distributed generations and demands. The various components of the DC microgrid were designed and built including DC-DC converters, voltage source inverters (VSI) and AC-DC rectifiers featuring novel designs developed by the candidate. New control techniques were developed and implemented to maximize the operating range of the power conditioning units used for integrating renewable energy into the DC bus. The control and operation of the DC microgrids in the hybrid AC/DC system involve intelligent energy management. Real-time energy management algorithms were developed and experimentally verified. These algorithms are based on intelligent decision-making elements along with an optimization process. This was aimed at enhancing the overall performance of the power system and mitigating the effect of heavy non-linear loads with variable intensity and duration. The developed algorithms were also used for managing the charging/discharging process of plug-in electric vehicle emulators. The protection of the proposed hybrid AC/DC power system was studied. Fault analysis and protection scheme and coordination, in addition to ideas on how to retrofit currently available protection concepts and devices for AC systems in a DC network, were presented. A study was also conducted on the effect of changing the distribution architecture and distributing the storage assets on the various zones of the network on the system's dynamic security and stability. A practical shipboard power system was studied as an example of a hybrid AC/DC power system involving pulsed loads. Generally, the proposed hybrid AC/DC power system, besides most of the ideas, controls and algorithms presented in this dissertation, were experimentally verified at the Smart Grid Testbed, Energy Systems Research Laboratory. All the developments in this dissertation were experimentally verified at the Smart Grid Testbed.

The Instrumental Model

ERIC Educational Resources Information Center

Yeates, Devin Rodney

2011-01-01

The goal of this dissertation is to enable better predictive models by engaging raw experimental data through the Instrumental Model. The Instrumental Model captures the protocols and procedures of experimental data analysis. The approach is formalized by encoding the Instrumental Model in an XML record. Decoupling the raw experimental data from…

System level modeling and component level control of fuel cells

NASA Astrophysics Data System (ADS)

Xue, Xingjian

This dissertation investigates the fuel cell systems and the related technologies in three aspects: (1) system-level dynamic modeling of both PEM fuel cell (PEMFC) and solid oxide fuel cell (SOFC); (2) condition monitoring scheme development of PEM fuel cell system using model-based statistical method; and (3) strategy and algorithm development of precision control with potential application in energy systems. The dissertation first presents a system level dynamic modeling strategy for PEM fuel cells. It is well known that water plays a critical role in PEM fuel cell operations. It makes the membrane function appropriately and improves the durability. The low temperature operating conditions, however, impose modeling difficulties in characterizing the liquid-vapor two phase change phenomenon, which becomes even more complex under dynamic operating conditions. This dissertation proposes an innovative method to characterize this phenomenon, and builds a comprehensive model for PEM fuel cell at the system level. The model features the complete characterization of multi-physics dynamic coupling effects with the inclusion of dynamic phase change. The model is validated using Ballard stack experimental result from open literature. The system behavior and the internal coupling effects are also investigated using this model under various operating conditions. Anode-supported tubular SOFC is also investigated in the dissertation. While the Nernst potential plays a central role in characterizing the electrochemical performance, the traditional Nernst equation may lead to incorrect analysis results under dynamic operating conditions due to the current reverse flow phenomenon. This dissertation presents a systematic study in this regard to incorporate a modified Nernst potential expression and the heat/mass transfer into the analysis. The model is used to investigate the limitations and optimal results of various operating conditions; it can also be utilized to perform the optimal design of tubular SOFC. With the system-level dynamic model as a basis, a framework for the robust, online monitoring of PEM fuel cell is developed in the dissertation. The monitoring scheme employs the Hotelling T2 based statistical scheme to handle the measurement noise and system uncertainties and identifies the fault conditions through a series of self-checking and conformal testing. A statistical sampling strategy is also utilized to improve the computation efficiency. Fuel/gas flow control is the fundamental operation for fuel cell energy systems. In the final part of the dissertation, a high-precision and robust tracking control scheme using piezoelectric actuator circuit with direct hysteresis compensation is developed. The key characteristic of the developed control algorithm includes the nonlinear continuous control action with the adaptive boundary layer strategy.

Three Dimensional Positron Annihilation Momentum Spectroscopy of Lithium Tetraborate Crystals

DTIC Science & Technology

2013-03-21

Technique Applied to Measure Oxygen-Atom Defects in 6H Silicon Carbide ." AFIT PhD Dissertation. AFIT/DS/ENP/10-M02, (Mar 2010) [4] Charlton, M., and...of Experimental Observables of Positron-Vacancy Complexes in Silicon Carbide .” Ph.D. dissertation, Air Force Institute of Technology, 2005. [18...Resonances ............................ 19 2.1.2 3D Positron Annihilation Momentum Measurements (3DPAMMs) of 6H SiC

Characterization and modeling of viscoelastic behavior of carbon nanotube reinforced polymers: The influence of interphase and nanotube morphology

NASA Astrophysics Data System (ADS)

Liu, Hua

The addition of nanoparticles into polymer materials has been observed to dramatically change the mechanical, thermal, electrical, and diffusion properties of the host polymers, promising a novel class of polymer matrix composite materials with superior properties and added functionalities that are ideal candidates in many applications, including aerospace, automobile, medical devices, and sporting goods. Understanding the behavior and underlying mechanisms of these polymer nanocomposites is critical. The research work presented in this dissertation represents one of the initial efforts in the long journey pursuing the ultimate understanding of nanoparticle reinforced polymer systems. Particular focal points are experimental evaluation and the development of appropriate modeling methods to capture the influence of the interphase on the overall viscoelastic behavior of carbon nanotube reinforced polymer nanocomposites. The first portion of this dissertation study investigates the viscoelastic behavior of MWCNT based PMMA nanocomposites, which complements our previous study of SWCNT/PMMA systems to confirm functionalization of nanotubes as an effective way to manipulate the interaction between nanotube and polymers and control the properties of the interphase region forming around the nanotubes and consequently change the overall performance of nanotube based polymer nanocomposites. In the second portion of this dissertation, we present a novel hybrid numerical-analytical modeling method that is capable of predicting viscoelastic behavior of multiphase polymer nanocomposites, in which the nanoscopic fillers can assume complex configurations. By combining the finite element technique and a micromechanical approach (particularly, the Mori-Tanaka method) with local phase properties, this method operates at low computational cost and effectively accounts for the influence of the interphase as well as in situ nanoparticle morphology. This modeling method is implemented two-dimensionally on nanotube and nanoplatelet based polymer nanocomposites. Given the experimentally measured frequency domain response of the bulk polymer, the viscoelastic behavior of the nanocomposites in both frequency and temperature domains can be calculated. The predicted pattern of influence of the interphase on the overall performance of the nanocomposites is consistent with the experimental observation. 3D parametric studies utilizing this modeling technique reveal that the nanotube morphology "modifies" the effect of interphase and hence profoundly influences the overall viscoelastic behavior. The findings help explain some experimental observations and furthermore, draw attention to the importance of morphology control through appropriate synthesis and processing techniques to further tune the thermomechanical behavior of the nanocomposites.

Characterization and damage evaluation of advanced materials

NASA Astrophysics Data System (ADS)

Mitrovic, Milan

Mechanical characterization of advanced materials, namely magnetostrictive and graphite/epoxy composite materials, is studied in this dissertation, with an emphasis on damage evaluation of composite materials. Consequently, the work in this dissertation is divided into two parts, with the first part focusing on characterization of the magneto-elastic response of magnetostrictlve materials, while the second part of this dissertation describes methods for evaluating the fatigue damage in composite materials. The objective of the first part of this dissertation is to evaluate a nonlinear constitutive relation which more closely depict the magneto-elastic response of magnetostrictive materials. Correlation between experimental and theoretical values indicate that the model adequately predicts the nonlinear strain/field relations in specific regimes, and that the currently employed linear approaches are inappropriate for modeling the response of this material in a structure. The objective of the second part of this dissertation is to unravel the complexities associated with damage events associated with polymeric composite materials. The intent is to characterize and understand the influence of impact and fatigue induced damage on the residual thermo-mechanical properties and compressive strength of composite systems. The influence of fatigue generated matrix cracking and micro-delaminations on thermal expansion coefficient (TEC) and compressive strength is investigated for woven graphite/epoxy composite system. Experimental results indicate that a strong correlation exists between TEC and compressive strength measurements, indicating that TEC measurements can be used as a damage metric for this material systems. The influence of delaminations on the natural frequencies and mode shapes of a composite laminate is also investigated. Based on the changes of these parameters as a function of damage, a methodology for determining the size and location of damage is suggested. Finally, the influence of loading parameters on impact damage growth is investigated experimentally though constant amplitude and spectrum loading fatigue tests. Based on observed impact damage growth during these tests it is suggested that the low load levels can be deleted from the standardized test sequence without significant influence on impact damage propagation.

Agriculture & Agronomy: A Dissertation Bibliography.

ERIC Educational Resources Information Center

1978

This bibliography presents a compilation of Agriculture and Agronomy doctoral research for the years 1973-1976. Each of the 3,386 doctoral dissertations cited herein has been accepted by accredited degree-granting universities in North America and published by University Microfilms International (UMI). Dissertations are arranged alphabetically in…

Hot and cold water as a supercritical solvent

NASA Astrophysics Data System (ADS)

Fuentevilla, Daphne Anne

This dissertation addresses the anomalous properties of water at high temperatures near the vapor-liquid critical point and at low temperatures in the supercooled liquid region. The first part of the dissertation is concerned with the concentration dependence of the critical temperature, density, and pressure of an aqueous sodium chloride solution. Because of the practical importance of an accurate knowledge of critical parameters for industrial, geochemical, and biological applications, an empirical equation for the critical locus of aqueous sodium chloride solutions was adopted in 1999 by the International Association for the Properties of Water and Steam (IAPWS) as a guideline. However, since this original Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride was developed, two new theoretical developments occurred, motivating the first part of this dissertation. Here, I present a theory-based formulation for the critical parameters of aqueous sodium chloride solutions as a proposed replacement for the empirical formulation currently in use. This formulation has been published in the International Journal of Thermophysics and recommended by the Executive Committee of IAPWS for adoption as a Revised Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride. The second part of the dissertation addresses a new concept, considering cold water as a supercritical solvent. Based on the idea of a second, liquid-liquid, critical point in supercooled water, we explore the possibility of supercooled water as a novel supercooled solvent through the thermodynamics of critical phenomena. In 2006, I published a Physical Review letter presenting a parametric scaled equation of state for supercooled-water. Further developments based on this work led to a phenomenological mean-field "two-state" model, clarifying the nature of the phase separation in a polyamorphic single-component liquid. In this dissertation, I modify this two-state model to incorporate solutes. Critical lines emanating from the pure-water critical point show how even small additions of solute may significantly affect the thermodynamic properties and phase behavior of supercooled aqueous solutions. Some solutes, such as glycerol, can prevent spontaneous crystallization, thus making liquid-liquid separation in supercooled water experimentally accessible. This work will help in resolving the question on liquid polyamorphism in supercooled water.

Semantic Social Scaffolding for Capturing and Sharing Dissertation Experience

ERIC Educational Resources Information Center

Dimitrova, V.; Lau, L.; O'Rourke, R.

2011-01-01

This paper presents a novel collaborative tool--AWESOME Dissertation Environment (ADE)--which facilitates student learning through semantic social scaffolding: a new approach to dissertation writing challenges. These challenges revolve around three issues: timing of support; collective intelligence, and sense making strategies in tension with the…

Experimental Evaluation Methodology for Spacecraft Proximity Maneuvers in a Dynamic Environment

DTIC Science & Technology

2017-06-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA DISSERTATION EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY MANEUVERS IN A DYNAMIC...29, 2014 – June 16, 2017 4. TITLE AND SUBTITLE EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY MANEUVERS IN A DYNAMIC ENVIRONMENT 5...LEFT BLANK ii Approved for public release. Distribution is unlimited. EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY MANEUVERS IN A

Cognitive Appraisal of Dissertation Stress among Undergraduate Students

ERIC Educational Resources Information Center

Devonport, Tracey J.; Lane, Andrew M.

2006-01-01

The present study examined changes in primary and secondary appraisal, and coping strategies utilized in the final weeks leading to dissertation submission. Sixty volunteer Sports Studies dissertation students (male: n = 29; female: n = 31) completed an adapted Cognitive Appraisal of Health Scale (CAHS: Kessler, 1998), and Brief COPE (Carver,…

A Popularized Version of 21 Doctoral Dissertations. R & D Monograph 70.

ERIC Educational Resources Information Center

Klein, Lawrence R.; Ghozeil, Susan

This volume makes available to a broad readership dissertation findings from social and behavioral sciences research supported by the Employment and Training Administration. Each of twenty-one dissertations, rewritten in the vernacular, is presented in condensed form for primarily nonacademic readers. These popularized selections, which have been…

Quantum control and quantum tomography on neutral atom qudits

NASA Astrophysics Data System (ADS)

Sosa Martinez, Hector

Neutral atom systems are an appealing platform for the development and testing of quantum control and measurement techniques. This dissertation presents experimental investigations of control and measurement tools using as a testbed the 16-dimensional hyperfine manifold associated with the electronic ground state of cesium atoms. On the control side, we present an experimental realization of a protocol to implement robust unitary transformations in the presence of static and dynamic perturbations. We also present an experimental realization of inhomogeneous quantum control. Specifically, we demonstrate our ability to perform two different unitary transformations on atoms that see different light shifts from an optical addressing field. On the measurement side, we present experimental realizations of quantum state and process tomography. The state tomography project encompasses a comprehensive evaluation of several measurement strategies and state estimation algorithms. Our experimental results show that in the presence of experimental imperfections, there is a clear tradeoff between accuracy, efficiency and robustness in the reconstruction. The process tomography project involves an experimental demonstration of efficient reconstruction by using a set of intelligent probe states. Experimental results show that we are able to reconstruct unitary maps in Hilbert spaces with dimension ranging from d=4 to d=16. To the best of our knowledge, this is the first time that a unitary process in d=16 is successfully reconstructed in the laboratory.

The Transformation of Online Teaching Practice: Tracing Successful Online Teaching in Higher Education

ERIC Educational Resources Information Center

Baran, Evrim

2011-01-01

This dissertation was an in-depth investigation of successful online teaching in the context of higher education. It is presented in nontraditional dissertation format as approved by the Department of Curriculum and Instruction, Iowa State University. This dissertation includes three publishable journal articles that would represent Chapter 2, 3…

The Community College Baccalaureate Movement: Cutting-Edge Dissertation Research

ERIC Educational Resources Information Center

Hrabak, Michael R.

2009-01-01

In this review of dissertations, the researcher presents summaries of 10 of the most recent and cutting-edge dissertations focusing on the ever-growing and complex field of the community college baccalaureate movement. These studies focus on the gamut of specific legislation, case studies of particular programs and schools, financing of such…

Research Trends in Turkish Distance Education: A Content Analysis of Dissertations, 1986-2014

ERIC Educational Resources Information Center

Bozkurt, Aras; Kumtepe, Evrim Genc; Kumtepe, Alper Tolga; Aydin, Irem Erdem; Bozkaya, Müjgan; Aydin, Cengiz Hakan

2015-01-01

This paper presents a content analytic approach on doctoral dissertations in the field of distance education in Turkish Higher Education context from the years of 1986 through 2014. A total of 61 dissertations were examined to explore keywords, academic discipline, research areas, theoretical/conceptual frameworks, research designs, research…

Making Controlled Experimentation More Informative in Inquiry Investigations

ERIC Educational Resources Information Center

McElhaney, Kevin Wei Hong

2010-01-01

This dissertation incorporates three studies that examine how the design of inquiry based science instruction, dynamic visualizations, and guidance for experimentation contribute to physics students' understanding of science. I designed a week-long, technology-enhanced inquiry module on car collisions that logs students' interactions with a…

Scenarios of physics beyond the standard model

NASA Astrophysics Data System (ADS)

Fok, Ricky

This dissertation discusses three topics on scenarios beyond the Standard Model. Topic one is the effects from a fourth generation of quarks and leptons on electroweak baryogenesis in the early universe. The Standard Model is incapable of electroweak baryogenesis due to an insufficiently strong enough electroweak phase transition (EWPT) as well as insufficient CP violation. We show that the presence of heavy fourth generation fermions solves the first problem but requires additional bosons to be included to stabilize the electroweak vacuum. Introducing supersymmetric partners of the heavy fermions, we find that the EWPT can be made strong enough and new sources of CP violation are present. Topic two relates to the lepton avor problem in supersymmetry. In the Minimal Supersymmetric Standard Model (MSSM), the off-diagonal elements in the slepton mass matrix must be suppressed at the 10-3 level to avoid experimental bounds from lepton avor changing processes. This dissertation shows that an enlarged R-parity can alleviate the lepton avor problem. An analysis of all sensitive parameters was performed in the mass range below 1 TeV, and we find that slepton maximal mixing is possible without violating bounds from the lepton avor changing processes: mu → egamma; mu → e conversion, and mu → 3e. Topic three is the collider phenomenology of quirky dark matter. In this model, quirks are particles that are gauged under the electroweak group, as well as a dark" color SU(2) group. The hadronization scale of this color group is well below the quirk masses. As a result, the dark color strings never break. Quirk and anti-quirk pairs can be produced at the LHC. Once produced, they immediately form a bound state of high angular momentum. The quirk pair rapidly shed angular momentum by emitting soft radiation before they annihilate into observable signals. This dissertation presents the decay branching ratios of quirkonia where quirks obtain their masses through electroweak symmetry breaking. This dissertation includes previously published and unpublished co-authored material.

Successful Dissertations and Theses: A Guide to Graduate Student Research from Proposal to Completion.

ERIC Educational Resources Information Center

Madsen, David

A guide to writing dissertations and theses is presented that is primarily directed to doctoral and master's degree candidates but that may also be useful to the writer of scholarly papers, essays, and papers. Attention is directed to the following concerns: starting and completing the dissertation; working with the research adviser and advisory…

A Content Analysis of Dissertations in the Field of Educational Technology: The Case of Turkey

ERIC Educational Resources Information Center

Durak, Gurhan; Cankaya, Serkan; Yunkul, Eyup; Misirli, Zeynel Abidin

2018-01-01

The present study aimed at conducting content analysis on dissertations carried out so far in the field of Educational Technology in Turkey. A total of 137 dissertations were examined to determine the key words, academic discipline, research areas, theoretical frameworks, research designs and models, statistical analyses, data collection tools,…

Evaluating E-Training for Public Library Staff: A Quasi-Experimental Investigation

ERIC Educational Resources Information Center

Dalston, Teresa

2009-01-01

A comparative evaluation framework of instructional interventions for implementation of online training for public library staff would enable a better understanding of how to improve the effectiveness, efficiency and efficacy of training in certain training environments. This dissertation describes a quasi-experimental study of a two-week,…

Essays on Policy Evaluation with Endogenous Adoption

ERIC Educational Resources Information Center

Gentile, Elisabetta

2011-01-01

Over the last decade, experimental and quasi-experimental methods have been favored by researchers in empirical economics, as they provide unbiased causal estimates. However, when implementing a program, it is often not possible to randomly assign subjects to treatment, leading to a possible endogeneity bias. This dissertation consists of two…

Electro-Analytical Study of Material Interfaces Relevant for Chemical Mechanical Planarization and Lithium Ion Batteries

NASA Astrophysics Data System (ADS)

Turk, Michael C.

This dissertation work involves two areas of experimental research, focusing specifically on the applications of electro-analytical techniques for interfacial material characterization. The first area of the work is centered on the evaluation and characterization of material components used for chemical mechanical planarization (CMP) in the fabrication of semiconductor devices. This part also represents the bulk of the projects undertaken for the present dissertation. The other area of research included here involves exploratory electrochemical studies of certain electrolyte and electrode materials for applications in the development of advanced lithium ion secondary batteries. The common element between the two areas of investigation is the technical approach that combines a broad variety of electro-analytical characterization techniques to examine application specific functions of the associated materials and devices. The CMP related projects concentrate on designing and evaluating materials for CMP slurries that would be useful in the processing of copper interconnects for the sub-22 nm technology node. Specifically, ruthenium and cobalt are nontraditional barrier materials currently considered for the new interconnects. The CMP schemes used to process the structures based on these metals involve complex surface chemistries of Ru, Co and Cu (used for wiring lines). The strict requirement of defect-control while maintaining material removal by precisely regulated tribo-corrosion complicates the designs of the CMP slurries needed to process these systems. Since Ru is electrochemically more noble than Cu, the surface regions of Cu assembled in contact with Ru tend to generate defects due to galvanic corrosion in the CMP environment. At the same time, Co is strongly reactive in the typical slurry environment and is prone to developing galvanic corrosion induced by Cu. The present work explores a selected class of alkaline slurry formulations aimed at reducing these galvanic corrosions in chemically controlled low-pressure CMP. The CMP specific functions of the slurry components are characterized in the tribo-electro-analytical approach by using voltammetry, open circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS) in the presence as well as in the absence of surface abrasion, both with and without the inclusion of colloidal silica (SiO2) abrasives. The results are used to understand the reaction mechanisms responsible for supporting material removal and corrosion suppression. The project carried out in the area of Li ion batteries (LIBs) uses electro-analytical techniques to probe electrolyte characteristics as well as electrode material performance. The investigation concentrates on optimizing a tactically chosen set of electrolyte compositions for low-to-moderate temperature applications of lithium titanium oxide (LTO), a relatively new anode material for such batteries. For this application, mixtures of non-aqueous carbonate based solvents are studied in combination with lithium perchlorate. The temperature dependent conductivities of the electrolytes are rigorously measured and analyzed using EIS. The experimental considerations and the working principle of this EIS based approach are carefully examined and standardized in the course of this study. These experiments also investigate the effects of temperature variations (below room temperature) on the solid electrolyte interphase (SEI) formation characteristics of LTO in the given electrolytes. This dissertation is organized as follows: Each experimental system and its relevance for practical applications are briefly introduced in each chapter. The experimental approach and the motivation for carrying out the investigation are also noted in that context. The experimental details specific to the particular study are described. This is followed by the results and their discussion, and subsequently, by the specific conclusions drawn from the given set of experiments. A general summary of the obtained results is presented at the end of the dissertation. Possible extensions of the present studies have also been briefly noted there.

An Experimental Investigation towards Improvement of Thermoelectric Properties of Strontium Titanate Ceramics

NASA Astrophysics Data System (ADS)

Mehdizadeh Dehkordi, Arash

The direct energy conversion between heat and electricity based on thermoelectric effects is a topic of long-standing interest in condensed matter materials science. Experimental and theoretical investigations in order to understand the mechanisms involved and to improve the materials properties and conversion efficiency have been ongoing for more than half a century. While significant achievements have been accomplished in improving the properties of conventional heavy element based materials (such as Bi2Te 3 and PbTe) as well as the discovery of new materials systems for the close-to-room temperature and intermediate temperatures, high-temperature applications of thermoelectrics is still limited to one materials system, namely SiGe. Recently, oxides have exhibited great potential to be investigated for high-temperature thermoelectric power generation. The objective of this dissertation is to synthesize and investigate both electronic and thermal transport in strontium titanate (SrTiO3) ceramics in order to experimentally realize its potential and to ultimately investigate the possibility of further improvement of the thermoelectric performance of this perovskite oxide for mid- to high temperature applications. Developing a synthesis strategy and tuning various synthesis parameters to benefit the thermoelectric transport form the foundation of this study. It is worth mentioning that the results of this study has been employed to prepare targets for pulsed-laser deposition (PLD) to study the thermoelectric properties of corresponding thin films and superlattice structures at Dr. Husam Alshareef's group at King Abdullah University of Science and Technology (KAUST), Saudi Arabia. Considering the broad range of functionality of SrTiO3, the findings of this work will surely benefit other fields of research and application of this functional oxide such as photoluminescence, ferroelectricity or mixed-ionic electronic conductivity. This dissertation will ultimately attempt to answer the question, "Is it possible to further improve the thermoelectric properties of SrTiO 3-based ceramics?". The organization of the dissertation is as follows: In Chapter 1, the fundamental concepts in the thermoelectric theory is explained. Second, we briefly review the characteristics of "good" thermoelectric materials and highlight the differences exist between SrTiO3 and conventional thermoelectric materials. In Chapter 2, SrTiO3 is introduced and the electronic and thermal properties arising from its crystal structure are discussed. Chapter 3 is dedicated to the fundamentals of measurements of the electronic and thermal transport properties which are the backbone of the current work. Our experimental results are presented in Chapter 4 and 5. The synthesis and processing techniques to prepare doped SrTiO3 powder and bulk polycrystalline ceramic are presented in Chapter 3. The optimizations of the synthesis and densification parameters involved are presented and discussed in this chapter as well. Significant improvement achieved in the thermoelectric figure of merit of Pr-doped SrTiO3 and the studies performed to understand the results are presented in Chapter 5. Concluding remarks and future work are discussed in Chapter 6.

Segmental and Intonational Evidence for a Los Angeles Chicano Spanish Vernacular

ERIC Educational Resources Information Center

Andrade, Argelia

2012-01-01

This dissertation has two complementary objectives. First, the present study provides a contemporary reading of "hispanista" research about Mexican Spanish, including Chicano Spanish. In addition, this dissertation presents an overview and analysis of intonational findings of both Mexican Spanish (from the Los Altos region in Jalisco)…

Ultrasonic studies of high-temperature superconductors

NASA Astrophysics Data System (ADS)

Feller, Jeffrey Robert

1997-09-01

This dissertation consists roughly of two parts. The first part deals with YBa2Cu3O7-δ (YBCO) films deposited on piezoelectric (LiNbO3) substrates. Interdigital surface acoustic wave (SAW) devices (delay lines operating at center frequencies of 50 and 100 MHz) fabricated from YBCO films are examined; insertion loss measurements are presented, and electrode resistance effects are analyzed using equivalent circuit models. Sheet resistance and 168 MHz SAW attenuation measurements of a granular YBCO film on LiNbO3 are also presented. The experimental data are discussed in terms of a percolation theory that models the film as an array of identical YBCO grains connected by resistive junctions which, in the superconducting state behave as Josephson junctions. The normal state resistances of the junctions are assumed to be randomly distributed. In the second part of the dissertation, a number of novel techniques (SAW 'bridges,' the high frequency interdigital proximity probe, and weak acoustic coupling sampled continuous wave spectrometry), used in the study of the vortex state and structural transitions in the normal state of YBCO films and single crystals, are described. Evidence of the existence of a first order structural transition in the vicinity of 220 K is provided.

Individual Specialist versus Group Preparation for a Computer Programming Contest Involving Secondary Students

ERIC Educational Resources Information Center

McAllister, Deborah A.

1994-01-01

This dissertation investigates the effects of two different grouping strategies on secondary students concerning their preparation for, and performance at, a computer programming contest. Students were divided into two groups, experimental and control, for a 3-week treatment, followed by the contest. Students in the experimental group became…

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1984 (Vol. 45 Nos. 1 through 6).

ERIC Educational Resources Information Center

1984

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 19 titles deal with a variety of topics, including the following: (1) factual, elaborative, and inferential levels of text processing; (2) the effect of explicitly and implicitly presented rhetorical functions on the…

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through September 1977 (Vol. 38 Nos. 1 through 3).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 14 titles deal with the following topics: children's ability to read their own dictated oral language; adjunct structure and reading comprehension; learning and comprehension of simultaneously presented stimuli in children of…

The Role of the Dissertation in Scientific Careers.

ERIC Educational Resources Information Center

Porter, Alan L.; And Others

1982-01-01

Presents a profile of science Ph.D.'s and discusses the dissertation as research publishing patterns, predicting commitment to research, researchers versus nonresearchers, and the future of the Ph.D. degree. (JN)

Moving-Boundary Problems Associated with Lyopreservation

NASA Astrophysics Data System (ADS)

Gruber, Christopher Andrew

The work presented in this Dissertation is motivated by research into the preservation of biological specimens by way of vitrification, a technique known as lyopreservation. The operative principle behind lyopreservation is that a glassy material forms as a solution of sugar and water is desiccated. The microstructure of this glass impedes transport within the material, thereby slowing metabolism and effectively halting the aging processes in a biospecimen. This Dissertation is divided into two segments. The first concerns the nature of diffusive transport within a glassy state. Experimental studies suggest that diffusion within a glass is anomalously slow. Scaled Brownian motion (SBM) is proposed as a mathematical model which captures the qualitative features of anomalously slow diffusion while minimizing computational expense. This model is applied to several moving-boundary problems and the results are compared to a more well-established model, fractional anomalous diffusion (FAD). The virtues of SBM are based on the model's relative mathematical simplicity: the governing equation under FAD dynamics involves a fractional derivative operator, which precludes the use of analytical methods in almost all circumstances and also entails great computational expense. In some geometries, SBM allows similarity solutions, though computational methods are generally required. The use of SBM as an approximation to FAD when a system is "nearly classical'' is also explored. The second portion of this Dissertation concerns spin-drying, which is an experimental approach to biopreservation in a laboratory setting. A biospecimen is adhered to a glass wafer and this substrate is covered with sugar solution and rapidly spun on a turntable while water is evaporated from the film surface. The mathematical model for the spin-drying process includes diffusion, viscous fluid flow, and evaporation, among other contributions to the dynamics. Lubrication theory is applied to the model and an expansion in orthogonal polynomials is applied. The resulting system of equations is solved computationally. The influence of various experimental parameters upon the system dynamics is investigated, particularly the role of the spin rate. A convergence study of the solution verifies that the polynomial expansion method yields accurate results.

Frequency Response Function Based Damage Identification for Aerospace Structures

NASA Astrophysics Data System (ADS)

Oliver, Joseph Acton

Structural health monitoring technologies continue to be pursued for aerospace structures in the interests of increased safety and, when combined with health prognosis, efficiency in life-cycle management. The current dissertation develops and validates damage identification technology as a critical component for structural health monitoring of aerospace structures and, in particular, composite unmanned aerial vehicles. The primary innovation is a statistical least-squares damage identification algorithm based in concepts of parameter estimation and model update. The algorithm uses frequency response function based residual force vectors derived from distributed vibration measurements to update a structural finite element model through statistically weighted least-squares minimization producing location and quantification of the damage, estimation uncertainty, and an updated model. Advantages compared to other approaches include robust applicability to systems which are heavily damped, large, and noisy, with a relatively low number of distributed measurement points compared to the number of analytical degrees-of-freedom of an associated analytical structural model (e.g., modal finite element model). Motivation, research objectives, and a dissertation summary are discussed in Chapter 1 followed by a literature review in Chapter 2. Chapter 3 gives background theory and the damage identification algorithm derivation followed by a study of fundamental algorithm behavior on a two degree-of-freedom mass-spring system with generalized damping. Chapter 4 investigates the impact of noise then successfully proves the algorithm against competing methods using an analytical eight degree-of-freedom mass-spring system with non-proportional structural damping. Chapter 5 extends use of the algorithm to finite element models, including solutions for numerical issues, approaches for modeling damping approximately in reduced coordinates, and analytical validation using a composite sandwich plate model. Chapter 6 presents the final extension to experimental systems-including methods for initial baseline correlation and data reduction-and validates the algorithm on an experimental composite plate with impact damage. The final chapter deviates from development and validation of the primary algorithm to discuss development of an experimental scaled-wing test bed as part of a collaborative effort for developing structural health monitoring and prognosis technology. The dissertation concludes with an overview of technical conclusions and recommendations for future work.

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1982 (Vol. 43 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 39 titles deal with a variety of topics, including the following: (1) oral reading behaviors of early readers; (2) the effects of pictures and mode of presentation on the prose comprehension of third and fifth grade children of…

Rhetoric and Public Address: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1985 (Vol. 46 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 titles deal with the following topics: (1) the role of public discourse in the soil conservation movement from 1865 to 1935; (2) Dwight D. Eisenhower's public imagery of the Soviet Union and Communist China as presented in…

PhD Dissertation Proposal - Introduction to Dark Mix Concept: Gamma Measurements of Capsule Mixture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meaney, Kevin Daniel

Presentation slides: Intro to Inertial Confinement Fusion; Types of Mixture in ICF capsules; Previous mixture experiments; Dark Mix Concept; Measuring Dark Mix with Gamma Cherenkov Detector; Dissertation Outline.

Micromachined probes for laboratory plasmas

NASA Astrophysics Data System (ADS)

Chiang, Franklin Changta

As we begin to find more applications for plasmas in our everyday lives, the ability to characterize and understand their inner workings becomes increasingly important. Much of our current understanding of plasma physics comes from investigations conducted in diffuse, outer space plasmas where experimenters have no control over the environment or experimental conditions and one measures interesting phenomena only by chance when the spacecraft or satellite passes through them. Ideally, experiments should be performed in a controlled environment, where plasma events can be deliberately and reliably created when wanted and probes placed precisely within the plasma. Unfortunately, often due to their size, probes used in outer space are unsuitable for use in high-density laboratory plasmas, and constructing probes that can be used in terrestrial plasmas is a considerable challenge. This dissertation presents the development, implementation, and experimental results of three micromachined probes capable of measuring voltage and electric field, ion energies, and changing magnetic fields (B-dot) in laboratory plasmas.

Design, fabrication and analysis of integrated optical waveguide devices

NASA Astrophysics Data System (ADS)

Sikorski, Yuri

Throughout the present dissertation, the main effort has been to develop the set of design rules for optical integrated circuits (OIC). At the present time, when planar optical integrated circuits seem to be the leading technology, and industry is heading towards much higher levels of integration, such design rules become necessary. It is known that analysis of light propagation in rectangular waveguides can not be carried out exactly. Various approximations become necessary, and their validity is discussed in this text. Various methods are used in the text for calculating the same problems, and results are compared. A few new concepts have been suggested to avoid approximations used elsewhere. The second part of this dissertation is directed to the development of a new technique for the fabrication of optical integrated circuits inside optical glass. This technique is based on the use of ultrafast laser pulses to alter the properties of glasses. Using this method we demonstrated the possibility of changing the refractive index of various passive and active optical glasses as well as ablating the material on the surface in a controlled fashion. A number of optical waveguide devices (e.g. waveguides, directional couplers, diffraction gratings, fiber Bragg gratings, V-grooves in dual-clad optical fibers, optical waveguide amplifiers) were fabricated and tested. Testing included measurements of loss/throughput, near-field mode profiles, efficiency and thermal stability. All of the experimental setup and test results are reported in the dissertation. We also demonstrated the possibility of using this technique to fabricate future bio-optical devices that will incorporate an OIC and a microfluidic circuit on a single substrate. Our results are expected to serve as a guide for the design and fabrication of a new generation of integrated optical and bio-optical devices.

Why scientists perform animal experiments, scientific or personal aim?

PubMed

Mayir, Burhan; Doğan, Uğur; Bilecik, Tuna; Yardımcı, Erdem Can; Çakır, Tuğrul; Aslaner, Arif; Mayir, Yeliz Akpınar; Oruç, Mehmet Tahir

2016-01-01

Although all animal studies are conducted in line with a specific purpose, we think that not all animal studies are performed for a scientific purpose but for personal curiosity or to fulfill a requirement. The aim of the present study is to reveal the purposes of experimental studies conducted on animals. We searched for experimental studies performed on rats in general surgery clinics via PubMed, and obtained the e-mail addresses of the corresponding authors for each study. Afterwards, we sent a 7-item questionnaire to the authors and awaited their responses. Seventy-three (22.2%) of 329 authors responded to the questionnaire. Within these studies, 31 (42.5%) were conducted as part of a dissertation, while the remaining 19 (26.0%) were conducted to meet the academic promotion criteria. Only 23 (31.5%) were conducted for scientific purposes. The cost of 41% of those studies was higher than 2500 $. As shown in this study, the main objective of carrying out animal studies in Turkey is usually to prepare a dissertation or to be entitled to academic promotion. Animal experiments must be planned and performed as scientific studies to support related clinical studies. Additionally, animal studies must have well-defined objectives and be carried out in line with scientific purposes that may lead to useful developments in medicine, rather than personal interests.

Control of Vibratory Energy Harvesters in the Presence of Nonlinearities and Power-Flow Constraints

NASA Astrophysics Data System (ADS)

Cassidy, Ian L.

Over the past decade, a significant amount of research activity has been devoted to developing electromechanical systems that can convert ambient mechanical vibrations into usable electric power. Such systems, referred to as vibratory energy harvesters, have a number of useful of applications, ranging in scale from self-powered wireless sensors for structural health monitoring in bridges and buildings to energy harvesting from ocean waves. One of the most challenging aspects of this technology concerns the efficient extraction and transmission of power from transducer to storage. Maximizing the rate of power extraction from vibratory energy harvesters is further complicated by the stochastic nature of the disturbance. The primary purpose of this dissertation is to develop feedback control algorithms which optimize the average power generated from stochastically-excited vibratory energy harvesters. This dissertation will illustrate the performance of various controllers using two vibratory energy harvesting systems: an electromagnetic transducer embedded within a flexible structure, and a piezoelectric bimorph cantilever beam. Compared with piezoelectric systems, large-scale electromagnetic systems have received much less attention in the literature despite their ability to generate power at the watt--kilowatt scale. Motivated by this observation, the first part of this dissertation focuses on developing an experimentally validated predictive model of an actively controlled electromagnetic transducer. Following this experimental analysis, linear-quadratic-Gaussian control theory is used to compute unconstrained state feedback controllers for two ideal vibratory energy harvesting systems. This theory is then augmented to account for competing objectives, nonlinearities in the harvester dynamics, and non-quadratic transmission loss models in the electronics. In many vibratory energy harvesting applications, employing a bi-directional power electronic drive to actively control the harvester is infeasible due to the high levels of parasitic power required to operate the drive. For the case where a single-directional drive is used, a constraint on the directionality of power-flow is imposed on the system, which necessitates the use of nonlinear feedback. As such, a sub-optimal controller for power-flow-constrained vibratory energy harvesters is presented, which is analytically guaranteed to outperform the optimal static admittance controller. Finally, the last section of this dissertation explores a numerical approach to compute optimal discretized control manifolds for systems with power-flow constraints. Unlike the sub-optimal nonlinear controller, the numerical controller satisfies the necessary conditions for optimality by solving the stochastic Hamilton-Jacobi equation.

Supporting CRME Online.

ERIC Educational Resources Information Center

Repp, Richard S.; Smith, Kenneth H.

1999-01-01

Discusses the content of the Council for Research in Music Education (CRME), noting sections on dissertations available for review, dissertations in progress, and test files. Summarizes the literature review conducted to inform the CRME website design and the inclusion and presentation of materials. (CMK)

Understanding the Structure-Function Relationships of Dendrimers in Environmental and Biomedical Applications

NASA Astrophysics Data System (ADS)

Wang, Bo

We are living an era wherein nanoparticles (NPs) have been widely applied in our lives. Dendrimers are special polymeric NPs with unique physiochemical properties, which have been intensely explored for a variety of applications. Current studies on dendrimers are bottlenecked by insufficient understandings of their structure and dynamic behaviors from a molecular level. With primarily computational approaches supplemented by many other experimental technics, this dissertation aims to establish structure-function relationships of dendrimers in environmental and biomedical applications. More specifically, it thoroughly investigates the interactions between dendrimers and different biomolecules including carbon-based NPs, metal-based NPs, and proteins/peptides. Those results not only provide profound knowledge for evaluating the impacts of dendrimers on environmental and biological systems but also facilitate designing next-generation functional polymeric nanomaterials. The dissertation is organized as following. Chapter 1 provides an overview of current progresses on dendrimer studies, where methodology of Discrete Molecular Dynamics (DMD), my major research tool, is also introduced. Two directions of utilizing dendrimers will be discussed in following chapters. Chapter 2 will focus on environmental applications of dendrimers, where two back-to-back studies are presented. I will start from describing some interesting observations from experiments i.e. dendrimers dispersed model oil molecules. Then, I will reveal why surface chemistries of dendrimers lead to different remediation efficiencies by computational modelings. Finally, I will demonstrate different scenarios of dendrimer-small molecules association. Chapter 3 is centered on dendrimers in the biomedical applications including two subtopics. In the first topic, we will discuss dendrimers as surfactants that modulating the interactions between proteins and NPs. Some fundamental concepts regarding to NPs-Protein interactions such as NP-protein corona are also explained. In the following topic, I will look into amyloid protein aggregation mediated by dendrimers, which is of high expectations for combating amyloidogenic-related diseases. Chapter 4 concludes the whole dissertation. It also briefly introduces my ongoing projects and future research directions about dendrimers. This dissertation has presented a systematic study of dendrimers in environmental and biomedical applications which might provide valuable information for future dendrimer design thus benefit the nanobiotechnology.

Designing Science Learning Environments That Support Emerging Bilingual Students to Problematize Electrical Phenomena

NASA Astrophysics Data System (ADS)

Suarez, Enrique A.

This dissertation investigates how emerging bilingual students make sense of natural phenomena through engaging in certain epistemic practices of science, and the elements of the learning environment that created those opportunities. Specifically, the dissertation focuses on how emerging bilingual students problematized electrical phenomena, like electric flow and electrical resistance, and how the design features of the environment (e.g., sequencing of activities, linguistic practices) may have supported students as they made sense of phenomena. The first study describes how for students presented and evaluated mechanistic models of electric flow, focusing specifically on how students identified and negotiated a disagreement between their explanatory models. The results from this study highlight the complexity of students' disagreements, not only because of the epistemological aspects related to presenting and evaluating knowledge, but also due to interpersonal dynamics and the discomfort associated with disagreeing with another person. The second study focuses on the design features of the learning environment that supported emerging bilingual students' investigations of electrical phenomena. The findings from this study highlight how a carefully designed set of activities, with the appropriate material resources (e.g., experimental tools), could support students to problematize electrical resistance. The third study describes how emerging bilingual students engaged in translanguaging practices and the contextual features of the learning environment that created and hindered opportunities for translanguaging. The findings from this study identify and articulate how emerging bilingual students engaged in translanguaging practices when problematizing electrical resistance, and strengthen the perspective that, in order to be equitable for emerging bilingual students, science learning environments need to act as translanguaging spaces. This dissertation makes three contributions to how science educators understand how elementary-aged emerging bilingual students learning science. First, I offer a detailed account of how emerging bilingual students engaged in epistemic practices to problematize electrical phenomena. Secondly, I argue learning environments need to create opportunities for emerging bilingual students to engage in productive epistemic work through leveraging multiple kinds of resources from their semiotic repertoires. Finally, this dissertation contributes to our understanding of how emerging bilingual students engage in translanguaging practices as they investigate and talk about the natural world.

Acceleration of aircraft-level Traffic Flow Management

NASA Astrophysics Data System (ADS)

Rios, Joseph Lucio

This dissertation describes novel approaches to solving large-scale, high fidelity, aircraft-level Traffic Flow Management scheduling problems. Depending on the methods employed, solving these problems to optimality can take longer than the length of the planning horizon in question. Research in this domain typically focuses on the quality of the modeling used to describe the problem and the benefits achieved from the optimized solution, often treating computational aspects as secondary or tertiary. The work presented here takes the complementary view and considers the computational aspect as the primary concern. To this end, a previously published model for solving this Traffic Flow Management scheduling problem is used as starting point for this study. The model proposed by Bertsimas and Stock-Patterson is a binary integer program taking into account all major resource capacities and the trajectories of each flight to decide which flights should be held in which resource for what amount of time in order to satisfy all capacity requirements. For large instances, the solve time using state-of-the-art solvers is prohibitive for use within a potential decision support tool. With this dissertation, however, it will be shown that solving can be achieved in reasonable time for instances of real-world size. Five other techniques developed and tested for this dissertation will be described in detail. These are heuristic methods that provide good results. Performance is measured in terms of runtime and "optimality gap." We then describe the most successful method presented in this dissertation: Dantzig-Wolfe Decomposition. Results indicate that a parallel implementation of Dantzig-Wolfe Decomposition optimally solves the original problem in much reduced time and with better integrality and smaller optimality gap than any of the heuristic methods or state-of-the-art, commercial solvers. The solution quality improves in every measureable way as the number of subproblems solved in parallel increases. A maximal decomposition provides the best results of any method tested. The convergence qualities of Dantzig-Wolfe Decomposition have been criticized in the past, so we examine what makes the Bertsimas-Stock Patterson model so amenable to use of this method. These mathematical qualities of the model are generalized to provide guidance on other problems that may benefit from massively parallel Dantzig-Wolfe Decomposition. This result, together with the development of the software, and the experimental results indicating the feasibility of real-time, nationwide Traffic Flow Management scheduling represent the major contributions of this dissertation.

An experimental and theoretical investigation of a fuel system tuner for the suppression of combustion driven oscillations

NASA Astrophysics Data System (ADS)

Scarborough, David E.

Manufacturers of commercial, power-generating, gas turbine engines continue to develop combustors that produce lower emissions of nitrogen oxides (NO x) in order to meet the environmental standards of governments around the world. Lean, premixed combustion technology is one technique used to reduce NOx emissions in many current power and energy generating systems. However, lean, premixed combustors are susceptible to thermo-acoustic oscillations, which are pressure and heat-release fluctuations that occur because of a coupling between the combustion process and the natural acoustic modes of the system. These pressure oscillations lead to premature failure of system components, resulting in very costly maintenance and downtime. Therefore, a great deal of work has gone into developing methods to prevent or eliminate these combustion instabilities. This dissertation presents the results of a theoretical and experimental investigation of a novel Fuel System Tuner (FST) used to damp detrimental combustion oscillations in a gas turbine combustor by changing the fuel supply system impedance, which controls the amplitude and phase of the fuel flowrate. When the FST is properly tuned, the heat release oscillations resulting from the fuel-air ratio oscillations damp, rather than drive, the combustor acoustic pressure oscillations. A feasibility study was conducted to prove the validity of the basic idea and to develop some basic guidelines for designing the FST. Acoustic models for the subcomponents of the FST were developed, and these models were experimentally verified using a two-microphone impedance tube. Models useful for designing, analyzing, and predicting the performance of the FST were developed and used to demonstrate the effectiveness of the FST. Experimental tests showed that the FST reduced the acoustic pressure amplitude of an unstable, model, gas-turbine combustor over a wide range of operating conditions and combustor configurations. Finally, combustor acoustic pressure amplitude measurements made in using the model combustor were used in conjunction with model predicted fuel system impedances to verify the developed design rules. The FST concept and design methodology presented in this dissertation can be used to design fuel system tuners for new and existing gas turbine combustors to reduce, or eliminate altogether, thermo-acoustic oscillations.

A Grammar Library for Information Structure

ERIC Educational Resources Information Center

Song, Sanghoun

2014-01-01

This dissertation makes substantial contributions to both the theoretical and computational treatment of information structure, with an eye toward creating natural language processing applications such as multilingual machine translation systems. The aim of the present dissertation is to create a grammar library of information structure for the…

Supply Chain Interoperability Measurement

DTIC Science & Technology

2015-06-19

Supply Chain Interoperability Measurement DISSERTATION June 2015 Christos E. Chalyvidis, Major, Hellenic Air...ENS-DS-15-J-001 SUPPLY CHAIN INTEROPERABILITY MEASUREMENT DISSERTATION Presented to the Faculty Department of Operational Sciences...INTEROPERABILITY MEASUREMENT Christos E. Chalyvidis, BS, MSc. Major, Hellenic Air Force Committee Membership: Dr. A.W. Johnson Chair

The Effects of Flipping the Classroom on Specific Aspects of Critical Thinking in a Christian College: A Quasi-Experimental, Mixed-Methods Study

ERIC Educational Resources Information Center

Hantla, Bryce F.

2014-01-01

This quasi-experimental, mixed methods study analyzes the effects of the flipped classroom on the variables of a critical thinking rubric used by a Christian liberal arts college and compares these results with those of the California Critical Thinking Skills Test (CCTST). Second, this dissertation examines the effects of the flipped classroom on…

Improving Hall Thruster Plume Simulation through Refined Characterization of Near-field Plasma Properties

NASA Astrophysics Data System (ADS)

Huismann, Tyler D.

Due to the rapidly expanding role of electric propulsion (EP) devices, it is important to evaluate their integration with other spacecraft systems. Specifically, EP device plumes can play a major role in spacecraft integration, and as such, accurate characterization of plume structure bears on mission success. This dissertation addresses issues related to accurate prediction of plume structure in a particular type of EP device, a Hall thruster. This is done in two ways: first, by coupling current plume simulation models with current models that simulate a Hall thruster's internal plasma behavior; second, by improving plume simulation models and thereby increasing physical fidelity. These methods are assessed by comparing simulated results to experimental measurements. Assessment indicates the two methods improve plume modeling capabilities significantly: using far-field ion current density as a metric, these approaches used in conjunction improve agreement with measurements by a factor of 2.5, as compared to previous methods. Based on comparison to experimental measurements, recent computational work on discharge chamber modeling has been largely successful in predicting properties of internal thruster plasmas. This model can provide detailed information on plasma properties at a variety of locations. Frequently, experimental data is not available at many locations that are of interest regarding computational models. Excepting the presence of experimental data, there are limited alternatives for scientifically determining plasma properties that are necessary as inputs into plume simulations. Therefore, this dissertation focuses on coupling current models that simulate internal thruster plasma behavior with plume simulation models. Further, recent experimental work on atom-ion interactions has provided a better understanding of particle collisions within plasmas. This experimental work is used to update collision models in a current plume simulation code. Previous versions of the code assume an unknown dependence between particles' pre-collision velocities and post-collision scattering angles. This dissertation focuses on updating several of these types of collisions by assuming a curve fit based on the measurements of atom-ion interactions, such that previously unknown angular dependences are well-characterized.

Understanding space charge and controlling beam loss in high intensity synchrotrons

NASA Astrophysics Data System (ADS)

Cousineau, Sarah M.

Future high intensity synchrotrons will require unprecedented control of beam loss in order to comply with radiation safety regulations and to allow for safe, hands-on maintenance of machine hardware. A major cause of beam loss in high intensity synchrotrons is the space charge force of the beam, which can lead to beam halo and emittance dilution. This dissertation presents a comprehensive study of space charge effects in high intensity synchrotron beams. Experimental measurements taken at the Proton Storage Ring (PSR) in Los Alamos National Laboratory and detailed simulations of the experiments are used to identify and characterize resonances that affect these beams. The collective motion of the beam is extensively studied and is shown to be more relevant than the single particle dynamics in describing the resonance response. The emittance evolution of the PSR beam and methods for reducing the space-charge-induced emittance growth are addressed. In a separate study, the emittance evolution of an intense space charge beam is experimentally measured at the Cooler Injector Synchrotron (CIS) at Indiana University. This dissertation also investigates the sophisticated two-stage collimation system of the future Spallation Neutron Source (SNS) high intensity accumulator ring. A realistic Monte-Carlo collimation simulation is developed and used to optimize the SNS ring collimation system parameters. The finalized parameters and predicted beam loss distribution around the ring are presented. The collimators will additionally be used in conjunction with a set of fast kickers to remove the beam from the gap region before the rise of the extraction magnets. The gap cleaning process is optimized and the cleaning efficiency versus momentum spread of the beam is examined.

Hybrid Optical-Magnetic Traps for Studies of 2D Quantum Turbulence in Bose-Einstein Condensates

NASA Astrophysics Data System (ADS)

Myers, Jessica Ann

Turbulence appears in most natural and man-made flows. However, the analysis of turbulence is particularly difficult. Links between microscopic fluid dynamics and statistical signatures of turbulence appear unobtainable from the postulates of fluid dynamics making turbulence one of the most important unsolved theoretical problems in physics. Two-dimensional quantum turbulence (2DQT), an emerging field of study, involves turbulence in two-dimensional (2D) flows in superfluids, such as Bose-Einstein condensates (BECs). In 2D superfluids, a turbulent state can be characterized by a disordered distribution of numerous vortex cores. The question of how to effectively and efficiently generate turbulent states in superfluids is a fundamental question in the field of quantum turbulence. Therefore, experimental studies of vortex nucleation and the onset of turbulence in a superfluid are important for achieving a deeper understanding of the overall problem of turbulence. My PhD dissertation involves the study of vortex nucleation and the onset of turbulence in quasi-2D BECs. First, I discuss experimental apparatus advancements that now enable BECs to be created in a hybrid optical-magnetic trap, an atom trapping configuration conducive to 2DQT experiments. Next, I discuss the design and construction of a quantum vortex microscope and initial vortex detection tests. Finally, I present the first experiments aimed at studying 2DQT carried out in the updated apparatus. Thermal counterflow in superfluid helium, in which the normal and superfluid components flow in opposite directions, is known to create turbulence in the superfluid. However, this phenomenon has not been simulated or studied in dilute-gas BECs as a possible vortex nucleation method. In this dissertation, I present preliminary data from the first experiments aimed at understanding thermal counterflow turbulence in dilute-gas BECs.

Polarimetry of random fields

NASA Astrophysics Data System (ADS)

Ellis, Jeremy

On temporal, spatial and spectral scales which are small enough, all fields are fully polarized. In the optical regime, however, instantaneous fields can rarely be examined, and, instead, only average quantities are accessible. The study of polarimetry is concerned with both the description of electromagnetic fields and the characterization of media a field has interacted with. The polarimetric information is conventionally presented in terms of second order field correlations which are averaged over the ensemble of field realizations. Motivated by the deficiencies of classical polarimetry in dealing with specific practical situations, this dissertation expands the traditional polarimetric approaches to include higher order field correlations and the description of fields fluctuating in three dimensions. In relation to characterization of depolarizing media, a number of fourth-order correlations are introduced in this dissertation. Measurements of full polarization distributions, and the subsequent evaluation of Stokes vector element correlations and Complex Degree of Mutual Polarization demonstrate the use of these quantities for material discrimination and characterization. Recent advancements in detection capabilities allow access to fields near their sources and close to material boundaries, where a unique direction of propagation is not evident. Similarly, there exist classical situations such as overlapping beams, focusing, or diffusive scattering in which there is no unique transverse direction. In this dissertation, the correlation matrix formalism is expanded to describe three dimensional electromagnetic fields, providing a definition for the degree of polarization of such a field. It is also shown that, because of the dimensionality of the problem, a second parameter is necessary to fully describe the polarimetric properties of three dimensional fields. Measurements of second-order correlations of a three dimensional field are demonstrated, allowing the determination of both the degree of polarization and the state of polarization. These new theoretical concepts and innovative experimental approaches introduced in this dissertation are expected to impact scientific areas as diverse as near field optics, remote sensing, high energy laser physics, fluorescence microscopy, and imaging.

Cognitive Adaptability: The Role of Metacognition and Feedback in Entrepreneural Decision Policies

DTIC Science & Technology

2005-01-01

their environments in such a way as to facilitate effective and dynamic cognitive functioning. In this dissertation, I present three complementary studies ...the study of metacognition (Jost, Kruglanski, and Nelson, 1998; Mischel, 1998; Schwarz, 1998b). This research has three goals, specifically to...environments in such a way as to facilitate effective and dynamic cognitive functioning. In this dissertation, I present three complementary studies that

Advancements in adaptive aerodynamic technologies for airfoils and wings

NASA Astrophysics Data System (ADS)

Jepson, Jeffrey Keith

Although aircraft operate over a wide range of flight conditions, current fixed-geometry aircraft are optimized for only a few of these conditions. By altering the shape of the aircraft, adaptive aerodynamics can be used to increase the safety and performance of an aircraft by tailoring the aircraft for multiple flight conditions. Of the various shape adaptation concepts currently being studied, the use of multiple trailing-edge flaps along the span of a wing offers a relatively high possibility of being incorporated on aircraft in the near future. Multiple trailing-edge flaps allow for effective spanwise camber adaptation with resulting drag benefits over a large speed range and load alleviation at high-g conditions. The research presented in this dissertation focuses on the development of this concept of using trailing-edge flaps to tailor an aircraft for multiple flight conditions. One of the major tasks involved in implementing trailing-edge flaps is in designing the airfoil to incorporate the flap. The first part of this dissertation presents a design formulation that incorporates aircraft performance considerations in the inverse design of low-speed laminar-flow adaptive airfoils with trailing-edge cruise flaps. The benefit of using adaptive airfoils is that the size of the low-drag region of the drag polar can be effectively increased without increasing the maximum thickness of the airfoil. Two aircraft performance parameters are considered: level-flight maximum speed and maximum range. It is shown that the lift coefficients for the lower and upper corners of the airfoil low-drag range can be appropriately adjusted to tailor the airfoil for these two aircraft performance parameters. The design problem is posed as a part of a multidimensional Newton iteration in an existing conformal-mapping based inverse design code, PROFOIL. This formulation automatically adjusts the lift coefficients for the corners of the low-drag range for a given flap deflection as required for the airfoil-aircraft matching. Examples are presented to illustrate the flapped-airfoil design approach for a general aviation aircraft and the results are validated by comparison with results from post-design aircraft performance computations. Once the airfoil is designed to incorporate a TE flap, it is important to determine the most suitable flap angles along the wing for different flight conditions. The second part of this dissertation presents a method for determining the optimum flap angles to minimize drag based on pressures measured at select locations on the wing. Computational flow simulations using a panel method are used "in the loop" for demonstrating closed-loop control of the flaps. Examples in the paper show that the control algorithm is successful in correctly adapting the wing to achieve the target lift distributions for minimizing induced drag while adjusting the wing angle of attack for operation of the wing in the drag bucket. It is shown that the "sense-and-adapt" approach developed is capable of handling varying and unpredictable inflow conditions. Such a capability could be useful in adapting long-span flexible wings that may experience significant and unknown atmospheric inflow variations along the span. To further develop the "sense-and-adapt" approach, the method was tested experimentally in the third part of the research. The goal of the testing was to see if the same results found computationally can be obtained experimentally. The North Carolina State University subsonic wind tunnel was used for the wind tunnel tests. Results from the testing showed that the "sense-and-adapt" approach has the same performance experimentally as it did computationally. The research presented in this dissertation is a stepping stone towards further development of the concept, which includes modeling the system in the Simulink environment and flight experiments using uninhabited aerial vehicles.

Spatially resolved, in-situ monitoring of crack growth via the coupling current in aluminum alloy 5083

NASA Astrophysics Data System (ADS)

Williams, Krystaufeux D.

The work discussed in this dissertation is an experimental validation of a body of research that was created to model stress corrosion cracking phenomenon for 304 stainless steels in boiling water reactors. This coupled environment fracture model (CEFM) incorporates the natural laws of the conservation of charge and the differential aeration hypothesis to predict the amount of stress corrosion crack growth as a function of many external environmental variables, including potential, stress intensity, solution conductivity, oxidizer concentrations, and various other environmental parameters. Out of this approach came the concept of the coupling current; a local corrosion current that flows from within cracks, crevices, pits, etc... of a metal or alloy to the external surface. Because of the deterministic approach taken in the mentioned research, the coupling current analysis and CEFM model can be applied to the specific problem of SCC in aluminum alloy 5083 (the alloy of interest for this dissertation that is highly sought after today because of its corrosion resistance and high strength to weight ratio). This dissertation research is specifically devoted to the experimental verification of the coupling current, which results from a coupling between the crack's internal and external environments, by spatially resolving them using the scanning vibrating probe (SVP) as a tool. Hence, through the use of a unique fracture mechanics setup, simultaneous mechanical and local electrochemical data may be obtained, in situ..

Re-Examining the Nature of Researcher-Participant Relationships in Qualitative Research.

ERIC Educational Resources Information Center

Busier, Holly-Lynn; Pigeon, Yvette

A qualitative research conversation needs to include a critical examination of a study's relational dimension. Excerpts are presented from two doctoral dissertations that discuss the nature of the researcher-participant relationships formed through the studies. The first dissertation, "Beyond the Yellow Brick Road: Educational Portraits of…

Poverty-Related Topics Found in Dissertations: A Bibliography.

ERIC Educational Resources Information Center

O'Neill, Mara, Comp.; And Others

Arranged alphabetically by main topic, this bibliography cites 322 doctoral dissertations, written between 1970 and 1974, pertaining to various aspects of poverty. Where possible, annotations have been written to present the kernel idea of the work. Im many instances, additional subject headings which reflect important secondary thrusts are also…

Bilingual/Bicultural Education: Titles and Abstracts of Doctoral Dissertations.

ERIC Educational Resources Information Center

California State Univ., Los Angeles. National Dissemination and Assessment Center.

Dissertation abstracts describing research on a wide variety of topics in bilingual education are presented. This publication is designed to provide background material for bilingual educators as well as practical procedures for bilingual teachers, administrators, counselors, and evaluators. The titles were acquired by using the two broad…

Moral Values in Contemporary Literature: A Teaching Dissertation.

ERIC Educational Resources Information Center

Aikins, Mary Patricia Truxler

This dissertation dealt with the preparation, design, teaching, and evaluation of a course in moral values in contemporary literature. Through lectures, group discussions, and multi-media presentations the course examined the possibility of using the moral approach to literary criticism as a form of analysis for contemporary literature. The course…

Transformative Learning Following Job Loss: A Dissertation Renewal

ERIC Educational Resources Information Center

Benway, Robert

2017-01-01

This study renews a doctoral dissertation written in 2003 on transformative learning following job loss. An abbreviated literature review compares corporate and worker circumstances from the original study to the present time. Findings show that corporations choose reductions in force due to pressure from investors instead of productivity, and…

A Model for Conducting and Assessing Interdisciplinary Undergraduate Dissertations

ERIC Educational Resources Information Center

Engström, Henrik

2015-01-01

This paper presents an effort to create a unified model for conducting and assessing undergraduate dissertations, shared by all disciplines involved in computer game development at a Swedish university. Computer game development includes technology-oriented disciplines as well as disciplines with aesthetical traditions. The challenge has been to…

IT Portfolio Selection and IT Synergy

ERIC Educational Resources Information Center

Cho, Woo Je

2010-01-01

This dissertation consists of three chapters. The primary objectives of this dissertation are: (1) to provide a methodological framework of IT (Information Technology) portfolio management, and (2) to identify the effect of IT synergy on IT portfolio selection of a firm. The first chapter presents a methodological framework for IT project…

Mungbam Grammar

ERIC Educational Resources Information Center

Lovegren, Jesse Stuart James

2013-01-01

This dissertation is an attempt to state what is known at present about the grammar of Mungbam (ISO 693-3 [mij]). Mungbam is a Niger-Congo language spoken in the Northwest Region of Cameroon. The dissertation is a descriptive grammar, covering the phonetics, phonology morphology and syntax of the language. Source data are texts and elicited data…

Lonely GPFUTV-the movement of water under the action of unknown vacuum

NASA Astrophysics Data System (ADS)

Lin, Weiyi

2013-11-01

In this paper, firstly, the experiment on the flow resistance of the aerated pipe flow is introduced. The experimental research on comparison between different volumes of air entrained is presented. Secondly, the characteristics of gravity pipe flow under the action of Torricelli's vacuum, shortly called as GPFUTV are dissertated, including creative and functional design, fundamental principle, etc. Under the joint action of an unknown vacuum energy and the formation of non-aerated flow the water flow is full-pipe and continuous, high-speed and non-rotational as distinguished from turbulent flow. Thirdly, an appeal in relation to the experimental research, the applied studies and basic theory research is given. For instance, experimental study of Torricelli's experiment phenomenon in the vacuum environment, applied study of the potential for GPFUTV to be developed for deep seawater suction technology and lifting technology for deep ocean mining, theoretical study of flow stability and flow resistance under GPFUTV condition, etc. At last, the famous GPFUTV project is illustrated. 12 years of rigorous and independent survey research.

From experiment to design -- Fault characterization and detection in parallel computer systems using computational accelerators

NASA Astrophysics Data System (ADS)

Yim, Keun Soo

This dissertation summarizes experimental validation and co-design studies conducted to optimize the fault detection capabilities and overheads in hybrid computer systems (e.g., using CPUs and Graphics Processing Units, or GPUs), and consequently to improve the scalability of parallel computer systems using computational accelerators. The experimental validation studies were conducted to help us understand the failure characteristics of CPU-GPU hybrid computer systems under various types of hardware faults. The main characterization targets were faults that are difficult to detect and/or recover from, e.g., faults that cause long latency failures (Ch. 3), faults in dynamically allocated resources (Ch. 4), faults in GPUs (Ch. 5), faults in MPI programs (Ch. 6), and microarchitecture-level faults with specific timing features (Ch. 7). The co-design studies were based on the characterization results. One of the co-designed systems has a set of source-to-source translators that customize and strategically place error detectors in the source code of target GPU programs (Ch. 5). Another co-designed system uses an extension card to learn the normal behavioral and semantic execution patterns of message-passing processes executing on CPUs, and to detect abnormal behaviors of those parallel processes (Ch. 6). The third co-designed system is a co-processor that has a set of new instructions in order to support software-implemented fault detection techniques (Ch. 7). The work described in this dissertation gains more importance because heterogeneous processors have become an essential component of state-of-the-art supercomputers. GPUs were used in three of the five fastest supercomputers that were operating in 2011. Our work included comprehensive fault characterization studies in CPU-GPU hybrid computers. In CPUs, we monitored the target systems for a long period of time after injecting faults (a temporally comprehensive experiment), and injected faults into various types of program states that included dynamically allocated memory (to be spatially comprehensive). In GPUs, we used fault injection studies to demonstrate the importance of detecting silent data corruption (SDC) errors that are mainly due to the lack of fine-grained protections and the massive use of fault-insensitive data. This dissertation also presents transparent fault tolerance frameworks and techniques that are directly applicable to hybrid computers built using only commercial off-the-shelf hardware components. This dissertation shows that by developing understanding of the failure characteristics and error propagation paths of target programs, we were able to create fault tolerance frameworks and techniques that can quickly detect and recover from hardware faults with low performance and hardware overheads.

An Analysis of Research Trends in Dissertations and Theses Studying Blended Learning

ERIC Educational Resources Information Center

Drysdale, Jeffery S.; Graham, Charles R.; Spring, Kristian J.; Halverson, Lisa R.

2013-01-01

This article analyzes the research of 205 doctoral dissertations and masters' theses in the domain of blended learning. A summary of trends regarding the growth and context of blended learning research is presented. Methodological trends are described in terms of qualitative, inferential statistics, descriptive statistics, and combined approaches…

Industrially-Situated Project-Based Learning: A Study of Feedback and Diffusion

ERIC Educational Resources Information Center

Gilbuena, Debra M.

2013-01-01

The Virtual Chemical Vapor Deposition (CVD) Process Development Project provides the context for the two areas of the research presented in this dissertation. The first area, generally referred to as feedback in this dissertation, focuses on student learning and the interactions of students and instructors that take place in the project,…

Access to Information in Both CitaDel and FirstSearch: A Comparative Study of Dissertation Coverage.

ERIC Educational Resources Information Center

Perry, Stephen; Salisbury, Lutishoor

1995-01-01

Presents a comparative analysis of electronic access to theses and dissertations through CitaDel and FirstSearch. Highlights include the effectiveness and ease of use in providing enduser access; strengths and weaknesses of searching capabilities; coverage; pricing; and examples of direct retrieval comparison. (LRW)

The Value of the Commonwealth: An Ecocritical History of Robinson Forest

ERIC Educational Resources Information Center

Gough, David Barrett

2013-01-01

This dissertation provides an ecocritical history of Robinson Forest, a southern Appalachian forest owned by the University of Kentucky. The objective of this dissertation is to examine the literary, environmental, and cultural history of Robinson Forest from its geologic formation to the present, paying particular attention to the production of…

Preparing Ed.D. Students to Conduct Group Dissertations

ERIC Educational Resources Information Center

Browne-Ferrigno, Tricia; Jensen, Jane McEldowney

2012-01-01

In this article we present an overview of a recently launched cohort-based Ed.D. program that prepares participants to conduct group dissertations. The program, a hybrid model of online learning activities and monthly face-to-face class sessions, is delivered through a partnership between a university's college of education and the administrative…

Social Studies Doctoral Dissertations in the United States and Turkey: A Comparative Study

ERIC Educational Resources Information Center

Savas, Behsat

2016-01-01

This study delves into 169 social studies doctoral dissertations published from January 2012 to October 2015. The results of the included studies were qualitatively synthesized and presented in narrative form in the results section. In preliminary searching for systematic reviews concerning social studies, we concentrated on 169 doctoral…

Preparing Future Teachers for Virtual Schooling: Assessing Their Preconceptions and Competence

ERIC Educational Resources Information Center

Charania, Amina

2010-01-01

This dissertation presents three research articles in the area of preparing preservice teachers for Virtual Schooling (VS). The context of the dissertation is embedded in a Teacher Education Goes Into Virtual Schooling (TEGIVS) project under the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education. The first…

Dissertation Research in Counseling Psychology: Topics, Methods, and Qualitative Training.

ERIC Educational Resources Information Center

Kopala, Mary; And Others

Findings from a survey that examined the vast scope of research training in counseling psychology programs and topical areas that are addressed in dissertation research are presented in this paper. The questionnaire included both open- and closed-ended questions and were completed by 166 recent graduates of doctoral programs in counseling…

Excited State Structural Dynamics of Carotenoids and ChargeTransfer Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Tassle, Aaron Justin

This dissertation describes the development andimplementation of a visible/near infrared pump/mid-infrared probeapparatus. Chapter 1 describes the background and motivation ofinvestigating optically induced structural dynamics, paying specificattention to solvation and the excitation selection rules of highlysymmetric molecules such as carotenoids. Chapter 2 describes thedevelopment and construction of the experimental apparatus usedthroughout the remainder of this dissertation. Chapter 3 will discuss theinvestigation of DCM, a laser dye with a fluorescence signal resultingfrom a charge transfer state. By studying the dynamics of DCM and of itsmethyl deuterated isotopomer (an otherwise identical molecule), we areable to investigate the origins of the charge transfer statemore » and provideevidence that it is of the controversial twisted intramolecular (TICT)type. Chapter 4 introduces the use of two-photon excitation to the S1state, combined with one-photon excitation to the S2 state of thecarotenoid beta-apo-8'-carotenal. These 2 investigations show evidencefor the formation of solitons, previously unobserved in molecular systemsand found only in conducting polymers Chapter 5 presents an investigationof the excited state dynamics of peridinin, the carotenoid responsiblefor the light harvesting of dinoflagellates. This investigation allowsfor a more detailed understanding of the importance of structuraldynamics of carotenoids in light harvesting.« less

Teaching and assessment of mathematical principles for software correctness using a reasoning concept inventory

NASA Astrophysics Data System (ADS)

Drachova-Strang, Svetlana V.

As computing becomes ubiquitous, software correctness has a fundamental role in ensuring the safety and security of the systems we build. To design and develop software correctly according to their formal contracts, CS students, the future software practitioners, need to learn a critical set of skills that are necessary and sufficient for reasoning about software correctness. This dissertation presents a systematic approach to both introducing these reasoning skills into the curriculum, and assessing how well the students have learned them. Specifically, it introduces a comprehensive Reasoning Concept Inventory (RCI) that captures the fine details of basic reasoning skills that are ideally learned across the undergraduate curriculum to reason about software correctness, to develop high quality software, and to understand why software works as specified. The RCI forms the basis for developing learning outcomes that help educators to assess the adequacy of current techniques and pinpoint necessary improvements. This dissertation contains results from experimentation and assessment over the past few years in multiple CS courses. The results show that the finer principles of mathematical reasoning of software correctness can be taught effectively and continuously improved with the help of the RCI using suitable teaching practices, and supporting methods and tools.

Research ethics in dissertations: ethical issues and complexity of reasoning.

PubMed

Kjellström, S; Ross, S N; Fridlund, B

2010-07-01

Conducting ethically sound research is a fundamental principle of scientific inquiry. Recent research has indicated that ethical concerns are insufficiently dealt with in dissertations. To examine which research ethical topics were addressed and how these were presented in terms of complexity of reasoning in Swedish nurses' dissertations. Analyses of ethical content and complexity of ethical reasoning were performed on 64 Swedish nurses' PhD dissertations dated 2007. A total of seven ethical topics were identified: ethical approval (94% of the dissertations), information and informed consent (86%), confidentiality (67%), ethical aspects of methods (61%), use of ethical principles and regulations (39%), rationale for the study (20%) and fair participant selection (14%). Four of those of topics were most frequently addressed: the majority of dissertations (72%) included 3-5 issues. While many ethical concerns, by their nature, involve systematic concepts or metasystematic principles, ethical reasoning scored predominantly at lesser levels of complexity: abstract (6% of the dissertations), formal (84%) and systematic (10%). Research ethics are inadequately covered in most dissertations by nurses in Sweden. Important ethical concerns are missing, and the complexity of reasoning on ethical principles, motives and implications is insufficient. This is partly due to traditions and norms that discount ethical concerns but is probably also a reflection of the ability of PhD students and supervisors to handle complexity in general. It is suggested that the importance of ethical considerations should be emphasised in graduate and post-graduate studies and that individuals with capacity to deal with systematic and metasystematic concepts are recruited to senior research positions.

The Far Infrared Vibration-Rotation Spectrum of the Ammonia Dimer.

NASA Astrophysics Data System (ADS)

Loeser, Jennifer Gertrud

1995-11-01

The ammonia dimer has been shown to exhibit unusual weak bonding properties relative to those of the other prototypical second row systems, the hydrogen fluoride dimer and the water dimer. The ultimate goal of the work initiated in this dissertation is to determine a complete intermolecular potential energy surface for the ammonia dimer. It is first necessary to observe its far infrared vibration-rotation-tunneling (VRT) spectrum and to develop a group theoretical model that explains this spectrum in terms of the internal dynamics of the ammonia dimer. These first steps are the subject of this dissertation. First, the current understanding of the ammonia dimer system is reviewed. Group theoretical descriptions of the nature of the ammonia dimer VRT states are explained in detail. An overview of the experimental and theoretical studies of the ammonia dimer made during the last decade is presented. Second, progress on the analysis of the microwave and far infrared spectrum of (ND_3)_2 below 13 cm^{-1} is reported. These spectra directly measure the 'donor -acceptor' interchange splittings in (ND_3) _2, and determine some of the monomer umbrella inversion tunneling splittings. Third, new 80-90 cm^{-1} far infrared spectra of (NH_3)_2 are presented and a preliminary analysis is proposed. Most of the new excited VRT states have been assigned as tunneling sublevels of an out-of-plane intermolecular vibration.

Optical diagnostics and computational modeling of reacting and non-reacting single and multiphase flows

NASA Astrophysics Data System (ADS)

Basu, Saptarshi

Three critical problem domains namely water transport in PEM fuel cell, interaction of vortices with diffusion flames and laminar diffusion layers and thermo-physical processes in droplets heated by a plasma or monochromatic radiation have been analyzed in this dissertation. The first part of the dissertation exhibits a unique, in situ, line-of-sight measurements of water vapor partial pressure and temperature in single and multiple gas channels on the cathode side of an operating PEM fuel cell. Tunable diode laser absorption spectroscopy was employed for these measurements for which water transitions sensitive to temperature and partial pressure were utilized. The technique was demonstrated in a PEM fuel cell operating under both steady state and time-varying load conditions. The second part of the dissertation is dedicated to the study of vortex interaction with laminar diffusion flame and non-reacting diffusion layers. For the non-reacting case, a detailed computational study of scalar mixing in a laminar vortex is presented for vortices generated between two gas streams. A detailed parametric study was conducted to determine the effects of vortex strength, convection time, and non-uniform temperature on scalar mixing characteristics. For the reacting case, an experimental study of the interaction of a planar diffusion flame with a line vortex is presented. The flame-vortex interactions are diagnosed by laser induced incandescence for soot yield and by particle image velocimetry for vortex flow characterization. The soot topography was studied as a function of the vortex strength, residence time, flame curvature and the reactant streams from which vortices are initiated. The third part of the dissertation is modeling of thermo-physical processes in liquid ceramic precursor droplets injected into plasma as used in the thermal spray industry to generate thermal barrier coatings on high value materials. Models include aerodynamic droplet break-up process, mixing of droplets in the high temperature plasma, heat and mass transfer within individual droplets as well as droplet precipitation and internal pressurization. The last part of the work is also concerned with the modeling of thermo-physical processes in liquid ceramic precursor droplets heated by monochromatic radiation. Purpose of this work was to evaluate the feasibility of studying precipitation kinetics and morphological changes in a droplet by mimicking similar heating rates as the plasma.

New approaches to provide ride-through for critical loads in electric power distribution systems

NASA Astrophysics Data System (ADS)

Montero-Hernandez, Oscar C.

2001-07-01

The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly-phase voltage sags. Algorithms capable of detecting voltage disturbances such as voltage sags, voltage swells, flicker, frequency change, and harmonics in a fast and reliable way are investigated and developed in this dissertation as an essential part of the approaches previously described. Simulation and experimental work has been done to validate the feasibility of all approaches under the most common voltage disturbances such as single-phase voltage sags and three-phase voltage sags.

Development of fault tolerant adaptive control laws for aerospace systems

NASA Astrophysics Data System (ADS)

Perez Rocha, Andres E.

The main topic of this dissertation is the design, development and implementation of intelligent adaptive control techniques designed to maintain healthy performance of aerospace systems subjected to malfunctions, external parameter changes and/or unmodeled dynamics. The dissertation is focused on the development of novel adaptive control configurations that rely on non-linear functions that appear in the immune system of living organisms as main source of adaptation. One of the main goals of this dissertation is to demonstrate that these novel adaptive control architectures are able to improve overall performance and protect the system while reducing control effort and maintaining adequate operation outside bounds of nominal design. This research effort explores several phases, ranging from theoretical stability analysis, simulation and hardware implementation on different types of aerospace systems including spacecraft, aircraft and quadrotor vehicles. The results presented in this dissertation are focused on two main adaptivity approaches, the first one is intended for aerospace systems that do not attain large angles and use exact feedback linearization of Euler angle kinematics. A proof of stability is presented by means of the circle Criterion and Lyapunov's direct method. The second approach is intended for aerospace systems that can attain large attitude angles (e.g. space systems in gravity-less environments), the adaptation is incorporated on a baseline architecture that uses partial feedback linearization of quaternions kinematics. In this case, the closed loop stability was analyzed using Lyapunov's direct method and Barbalat's Lemma. It is expected that some results presented in this dissertation can contribute towards the validation and certification of direct adaptive controllers.

Continuing review of ethics in clinical trials: a surveillance study in Iran

PubMed Central

Mohamadi, Amin; Asghari, Fariba; Rashidian, Arash

2014-01-01

In recent years, notable measures have been taken to protect the rights of participants in biomedical research in Iran. The present study examines possible trends in adherence to ethical codes regarding informed consent after the development of the National Code of Ethics in Biomedical Research (NCEBR) and establishment of research ethics committees. In this retrospective study, 126 dissertations from Tehran University of Medical Sciences were evaluated for adherence to ethical codes. These dissertations were all in clinical trial design and had been presented in the years 1999 and 2009, that is, precisely before and after the development of the NCEBR. A checklist was developed to evaluate the ethical issues associated with informed consent. A single investigator retrieved and evaluated the consent forms from the dissertations. Borderline cases were discussed with other investigators to reach a consensus decision. Based on the checklist, the Standardized Ethical Score (SES) was calculated for each consent form. The mean SES and the rate of consent form attachment were compared between the two years. In total, 70 dissertations had reported obtaining informed consent from study participants, whereas consent forms were attached in only 22 dissertations (17.50%). The percentage of dissertations with the consent form attached increased over time from 12.2% in 1999 to 20.8% in 2009 (P > 0.05), but the majority still did not include a consent form. Moreover, the mean SES of consent forms was significantly higher in 1999 (0.746) than in 2009 (0.428), highlighting the need for more training of researchers and improved surveillance by the ethics committees. A great amount of effort is still needed to make the consent process more ethical, especially for dissertations as a less visible part of academic research. As for students, more systematic training focused on research ethics should be implemented prior to thesis submission. PMID:26587202

From Dissertation Defense to Dissemination: Jump Start Your Academic Career With a Scholar Mentor Group.

PubMed

Lehna, Carlee; Hermanns, Melinda; Monsivais, Diane B; Engebretson, Joan

2016-01-01

The dissertation provides an excellent source of scholarly productivity for new doctoral faculty, yet is often neglected because of the demands inherent in the faculty role. The purpose of this paper is to present a case study of a scholar mentor group composed of three graduates of a PhD nursing program and their shared dissertation chair, who acted as a senior scholar mentor to the group. By working together, we have been able to enhance our scholarly productivity by disseminating our dissertations through presentations and publications. The paper will present the evolving process of this working group, summarize outcomes, analyze the challenges, and provide suggestions for future doctoral students and faculty who are working with them. Our experience and scholar mentor model captures the best of both worlds-the benefits of interaction with academic peers and the benefits of having a senior scholar mentor. This was accomplished while all members were at different schools in different cities and states. Although other literatures that document successful collaborations using a peer-mentorship model are available, we were unable to locate any that documents a post-doctoral group with a senior scholar mentor who continued working together after graduation. © 2015 Wiley Periodicals, Inc.

Impact of Process Protocol Design on Virtual Team Effectiveness

ERIC Educational Resources Information Center

Cordes, Christofer Sean

2013-01-01

This dissertation examined the influence of action process dimensions on team decision performance, and attitudes toward team work environment and procedures given different degrees of collaborative technology affordance. Process models were used to provide context for understanding team behavior in the experimental task, and clarify understanding…

An Experimental Investigation of Phonetic Naturalness

ERIC Educational Resources Information Center

Greenwood, Anna

2016-01-01

This dissertation begins with the observation of a typological asymmetry within phonological patterns related to phonetic naturalness. Patterns that are rooted within existing tendencies of perception and/or production--in other words, patterns that are phonetically "natural"--are common in phonological typology and seen in a variety of…

78 FR 77503 - Privacy Act of 1974; Privacy Act System of Records

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-23

... System Manager title. Human Experimental and Research Data Records/NASA 10HERD: Refine system locations... aeronautics, astronautics, space science, and other concerns of NASA. CATEGORIES OF RECORDS IN THE SYSTEM... and other disciplines) or any other interested individuals for research in writing dissertations...

A Formal Investigation of the Organization of Guidance Behavior: Implications for Humans and Autonomous Guidance

NASA Astrophysics Data System (ADS)

Kong, Zhaodan

Guidance behavior generated either by artificial agents or humans has been actively studied in the fields of both robotics and cognitive science. The goals of these two fields are different. The former is the automatic generation of appropriate or even optimal behavior, while the latter is the understanding of the underlying mechanism. Their challenges, though, are closely related, the most important one being the lack of a unified, formal and grounded framework where the guidance behavior can be modeled and studied. This dissertation presents such a framework. In this framework, guidance behavior is analyzed as the closed-loop dynamics of the whole agent-environment system. The resulting dynamics give rise to interaction patterns. The central points of this dissertation are that: first of all, these patterns, which can be explained in terms of symmetries that are inherent to the guidance behavior, provide building blocks for the organization of behavior; second, the existence of these patterns and humans' organization of their guidance behavior based on these patterns are the reasons that humans can generate successful behavior in spite of all the complexities involved in the planning and control. This dissertation first gives an overview of the challenges existing in both scientific endeavors, such as human and animal spatial behavior study, and engineering endeavors, such as autonomous guidance system design. It then lays out the foundation for our formal framework, which states that guidance behavior should be interpreted as the collection of the closed-loop dynamics resulting from the agent's interaction with the environment. The following, illustrated by examples of three different UAVs, shows that the study of the closed-loop dynamics should not be done without the consideration of vehicle dynamics, as is the common practice in some of the studies in both autonomous guidance and human behavior analysis. The framework, the core concepts of which are symmetries and interaction patterns, is then elaborated on with the example of Dubins' vehicle's guidance behavior. The dissertation then describes the details of the agile human guidance experiments using miniature helicopters, the technique that is developed for the analysis of the experimental data and the analysis results. The results confirm that human guidance behavior indeed exhibits invariance as defined by interaction patterns. Subsequently, the behavior in each interaction pattern is investigated using piecewise affine model identification. Combined, the results provide a natural and formal decomposition of the behavior that can be unified under a hierarchical hidden Markov model. By employing the languages of dynamical system and control and by adopting algorithms from system identification and machine learning, the framework presented in this dissertation provides a fertile ground where these different disciplines can meet. It also promises multiple potential directions where future research can be headed.

Ferroelectric liquid crystal device based photonic controllers for microwave antenna arrays

NASA Astrophysics Data System (ADS)

Madamopoulos, Nicholas

For the first time, this dissertation proposes, studies, analyzes, and experimentally demonstrates the use of ferroelectric liquid crystal (FLC) technology for wideband phased array control applications. FLC devices are used as polarization switches in photonic delay lines (PDLs) to control and process optical signals that drive the elements of a phased array antenna (PAA). The use of photonics for PAA control is, at present, a vital area of applied research. This dissertation work concludes with the demonstration of a multichannel 7-bit PDL system for a wideband PAA such as the Navy's advanced Aegis radar system. The unique system issues and problems to be examined and solved in this Ph.D. dissertation include the theoretical analysis and experimental demonstration of different PDL architectures covering a sub-nanosecond to several nanoseconds time delay range. New noise reduction/suppression schemes are proposed, studied and applied to give record level time delay system performance in terms of signal-to-leakage noise ratio, and switching speeds (e.g., 35 microseconds) required for fast radar scan. We show that the external modulation FO link gives more degrees of freedom to the system engineer, and we propose a novel synchronous RF signal calibration time delay control technique to obtain optimum dynamic range performance for our PDL. The use of low loss fibers for remoting of the photonic beamformer, as well as the losses associated with multiple fiber interconnects that limit the maximum number of array channels in the systems are studied. Different fiber optic coupling techniques are investigated for enhanced fiber coupling. Multimode fibers are used, for the first time, at the output plane of the PDL to obtain improved coupling efficiency. We demonstrate a low ~1.7 dB optical insertion loss/bit, which is very close to the desired insertion loss required for the Navy system. A novel approach for hardware reduction based on wavelength multiplexing is proposed, where the use of a combination of wavelength dependent and wavelength independent optical paths provides the required time delays. Finally, new switching fabric approaches are studied based on polarization selective holograms and their potential use for the implementation of PDLs is discussed.

Experimental and Numerical Analysis of Structural Acousticcontrol Interior Noise Reduction

NASA Technical Reports Server (NTRS)

Mei, Chuh; Bevan, Jeffrey S.

1999-01-01

The research results contained in this technical report were performed under the NASA grant entitled "Experimental and Numerical Structural Acoustic Control for Interior Noise Reduction". The report is based essentially on partial progress of the Ph.D. dissertation prepared by Jeffrey S. Bevan under direct guidance of Dr. Chuh Mei. The document presents a finite element formulation and control of sound radiated from cylindrical panels embedded with piezoceramic actuators. The extended MIN6 shallow shell element is fully electrical-structural coupled. A piezoelectric modal actuator participation (PMAP) is defined which indicates the actuator performance to each of the offending modes. Genetic algorithm is also employed to validate the sensor and actuator locations determined by the PMAP criteria. The work was conducted at the Department of Aerospace Engineering, Old Dominion University. Mr. Travis L. Turner, Structural Acoustics Branch, NASA Langley Research Center is the technical monitor.

The First Big Wave of Astronomy Education Research Dissertations and Some Directions for Future Research Efforts

ERIC Educational Resources Information Center

Slater, Timothy F.

2008-01-01

The past several years have presented the astronomy education research community with a host of foundational research dissertations in the teaching and learning of astronomy. These PhD candidates have been studying the impact of instructional innovations on student learning and systematically validating astronomy learning assessment instruments,…

Higher Education in American Life, 1636-1986. A Bibliography of Dissertations and Theses.

ERIC Educational Resources Information Center

Young, Arthur P., Comp.

A bibliography of master's theses and doctoral dissertations on higher education and its role in American life since 1636 presents citations in two major categories: works concerning a specific institution, listed by state and institution; and topical studies on specific aspects of higher education. The 4,570 citations were derived from sources…

Survey of U.S. Doctoral Degrees Related to the Teaching of German--2003 and 2005

ERIC Educational Resources Information Center

Benseler, David P.

2006-01-01

The current listing presents titles of doctoral dissertations related to the teaching of German and completed in U.S. universities during the "calendar" years 2003 and 2005. The term "related to the teaching of German" refers to dissertations completed in Germanics, comparative literature, linguistics, and foreign or second language education with…

Improved Wireless Security through Physical Layer Protocol Manipulation and Radio Frequency Fingerprinting

DTIC Science & Technology

2014-09-18

radios in a cognitive radio network using a radio frequency fingerprinting based method. In IEEE International Conference on Communications (ICC...IMPROVEDWIRELESS SECURITY THROUGH PHYSICAL LAYER PROTOCOL MANIPULATION AND RADIO FREQUENCY FINGERPRINTING DISSERTATION Benjamin W. Ramsey, Captain...PHYSICAL LAYER PROTOCOL MANIPULATION AND RADIO FREQUENCY FINGERPRINTING DISSERTATION Presented to the Faculty Graduate School of Engineering and

Guide to Theses and Dissertations: An International Bibliography of Bibliographies. Revised and Enlarged Edition.

ERIC Educational Resources Information Center

Reynolds, Michael M.

Annotations on 2,948 bibliographies of dissertations, theses, and research completed and in progress for graduate degrees are presented. The bibliographies, produced through 1983 and most of 1984, are specialized and usually subject-oriented and cover current and retrospective research in the United States and throughout the world. The annotations…

"How Did You Find the Argument?": Conflicting Discourses in a Master's Dissertation Tutorial

ERIC Educational Resources Information Center

Salter-Dvorak, Hania

2017-01-01

This paper discusses feedback for developing L2 writing. It presents data from a serendipitous audio-recording of one L2 master's student's tutorial with her dissertation supervisor at a UK university, which is extracted from a 13-month linguistic ethnography. Following "academic literacies" scholars, I view the tutorial as a…

Doctoral Dissertations on Japan and Korea, 1969-1974: A Classified Bibliographical Listing of International Research.

ERIC Educational Resources Information Center

Shulman, Frank Joseph, Ed.

This volume provides a comprehensive listing of dissertations on Japan and Korea that are available from University Microfilms International. The present bibliography incorporates many titles that normally would be overlooked because they do not relate directly to the Japanese home islands or to the Korean peninsula. Among the ones included, for…

FORTY YEARS OF SCHOOL PLANT DISSERTATIONS. A REVIEW WITH SUGGESTIONS FOR FUTURE RESEARCH.

ERIC Educational Resources Information Center

CLASEN, ROBERT E.

A BIBLIOGRAPHIC REVIEW OF PUBLISHED AND UNPUBLISHED DISSERTATIONS RELATED TO SCHOOL PLANTS IS COMPILED BY YEARS BEGINNING WITH STUDIES PRODUCED IN 1921 AND IS CROSS INDEXED BY TOPIC. IT REVIEWS THE SCHOOL PLANT PROBLEMS MOST INVESTIGATED BY STUDENTS. A BRIEF HISTORY OF SCHOOL BUILDING DEVELOPMENT IS PRESENTED IN LIGHT OF CORRESPONDING ECONOMIC AND…

E-Mentoring the Online Doctoral Student from the Dissertation Prospectus through Dissertation Completion

ERIC Educational Resources Information Center

Black, Ronald

2017-01-01

Faculty who mentor online doctoral candidates face many of the same challenges and opportunities as those mentoring doctoral candidates in traditional, face-to-face modalities. The main difference is that E-Mentoring is based on interacting in the online space rather than interacting face-to-face, which may present challenges for both the…

Content Analysis of Master Theses and Dissertations Based on Action Research

ERIC Educational Resources Information Center

Durak, Gürhan; Yünkül, Eyup; Cankaya, Serkan; Akpinar, Sükran; Erten, Emine; Inam, Nazmiye; Taylan, Ufuk; Tastekin, Eray

2016-01-01

Action Research (AR) is becoming popular in the field of education, and according to literature, it could be stated that AR studies have positive influence on practice in education. The present study aims at conducting content analysis of action research (AR) master theses and doctoral dissertations submitted at the level of Turkish higher…

Embrace and Ambivalence

ERIC Educational Resources Information Center

Kuhn, Virginia

2013-01-01

The digital dissertation has been here for almost a decade, but people in the academe still don't seem to know what to do with it. How should it be presented? How should it be archived? In August 2005, the author successfully defended a media-rich digital dissertation in the Department of English at the University of Wisconsin-Milwaukee (UWM). The…

The Reciprocal Relationship between Text Literacy and Music Literacy among Beginning Band Students

ERIC Educational Resources Information Center

Carroll, David Lawson

2017-01-01

This dissertation examines the reciprocal relationship between text literacy and music literacy through an experimental design. Music teachers and English Language Arts (ELA) teachers often address similar components of literacy, including fluency, comprehension, and symbolic interpretation. The theory of cognitive structuralism maintains that…

School-Based Peer Mentoring in High School: A Program Evaluation Study

ERIC Educational Resources Information Center

Cooper, Felicia Cecile

2017-01-01

The dissertation is an initial investigation of a peer mentoring program in a suburban high school in the southeastern United States. Additionally, the Peer Mentoring Program (PMP) study examined whether the Program improves academic performance and attendance, and decreases referrals. Utilizing an experimental design, a Participant and a…

Measuring Linguistic Empathy: An Experimental Approach to Connecting Linguistic and Social Psychological Notions of Empathy

ERIC Educational Resources Information Center

Kann, Trevor

2017-01-01

This dissertation investigated the relationship between Linguistic Empathy and Psychological Empathy by implementing a psycholinguistic experiment that measured a person's acceptability ratings of sentences with violations of Linguistic Empathy and correlating them with a measure of the person's Psychological Empathy. Linguistic Empathy…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uemura, Sho

The Heavy Photon Search (HPS) is a new experiment at Jefferson Lab that searches for a massive U(1) vector boson (known as a heavy photon or A′) in the MeV-GeV mass range and coupling weakly to ordinary matter through a kinetic mixing interaction. The HPS experiment seeks to produce heavy photons by electron bremsstrahlung on a fixed target, is sensitive to heavy photon decays to e+e-, and targets the range in heavy photon mass m_A' ~ 20 - 600 MeV, and kinetic mixing strength epsilon^2 ~ 10^-5 - 10^−10. HPS searches for heavy photons using two signatures: a narrow massmore » resonance and displaced vertices. This dissertation presents the theoretical and experimental motivations for a heavy photon, the design and operation of the HPS experiment, and the displaced vertex search. The data used in this dissertation is the unblinded fraction of the 2015 HPS run, for the period of operation where the HPS silicon vertex tracker (SVT) was operated at its nominal position. This data was recorded from May 13 to May 18, 2015, at a beam energy of 1.056 GeV and a nominal beam current of 50 nA. The integrated luminosity is 119 nb^-1, which is equivalent to 0.172 days of ideal running at the nominal beam current. This dissertation presents results (signal significance and upper limits) from the displaced vertex search in the mass range m_A' ~ 20 - 60 MeV, and kinetic mixing strength epsilon^2 ~ 2 × 10^-8 - 10^-10. This search does not have sufficient sensitivity to exclude a canonical heavy photon at any combination of m_A' and epsilon^2. The strictest limit achieved in this analysis on the production of a particle that decays like a heavy photon is 115 times the expected production cross-section for a heavy photon. Factors limiting the sensitivity of this analysis are discussed. Projections of HPSperformance with the full 2015 data set, and with planned improvements to theanalysis, are presented. Comparisons are also made to earlier reach estimates.« less

Model-Based Battery Management Systems: From Theory to Practice

NASA Astrophysics Data System (ADS)

Pathak, Manan

Lithium-ion batteries are now extensively being used as the primary storage source. Capacity and power fade, and slow recharging times are key issues that restrict its use in many applications. Battery management systems are critical to address these issues, along with ensuring its safety. This dissertation focuses on exploring various control strategies using detailed physics-based electrochemical models developed previously for lithium-ion batteries, which could be used in advanced battery management systems. Optimal charging profiles for minimizing capacity fade based on SEI-layer formation are derived and the benefits of using such control strategies are shown by experimentally testing them on a 16 Ah NMC-based pouch cell. This dissertation also explores different time-discretization strategies for non-linear models, which gives an improved order of convergence for optimal control problems. Lastly, this dissertation also explores a physics-based model for predicting the linear impedance of a battery, and develops a freeware that is extremely robust and computationally fast. Such a code could be used for estimating transport, kinetic and material properties of the battery based on the linear impedance spectra.

A biographical note on Max Friedrich (1856-1887), Wundt's first PhD student in experimental psychology.

PubMed

Domanski, Cezary W

2004-01-01

This article unveils some previously unknown facts about the short life of Max Friedrich (1856-1887), the author in 1881 of the first PhD dissertation on experimental psychology, written under the supervision of Wilhelm Wundt: "On the Duration of Apperception for Simple and Complex Visual Stimuli." The article describes Friedrich's family background and life, professional career as a teacher, and works in psychology and mathematics. Copyright 2004 Wiley Periodicals, Inc.

Psychobiography Training in Psychology in North America: Mapping the Field and Charting a Course

PubMed Central

Ponterotto, Joseph G.; Reynolds, Jason D.; Morel, Samantha; Cheung, Linda

2015-01-01

Psychobiography holds an important position in the history of psychology, yet little is known about the status of psychobiographical training and dissertation research in psychology departments. This brief report identified psychobiography courses throughout North America and content analyzed a sample of 65 psychobiography dissertations to discern the theories and methods that have most commonly anchored this research. Results identified few psychology courses specifically in psychobiography, with a larger number of courses incorporating psychobiographical and/or narrative elements. With regard to psychobiography dissertations, the majority focused on artists, pioneering psychologists, and political leaders. Theories undergirding psychobiographical studies were most frequently psychoanalytic and psychodynamic. Methodologically, a majority of the dissertations were anchored in constructivist (discovery-oriented) qualitative procedures, with a minority incorporating mixed methods designs. The authors highlight the value of psychobiographical training to psychology students and present avenues and models for incorporating psychobiography into psychology curriculums. PMID:27247670

"I've Never Done a Dissertation before Please Help Me": Accommodating L2 Students through Course Design

ERIC Educational Resources Information Center

Salter-Dvorak, Hania

2014-01-01

This article considers how course design accommodates the adaptation of L2 students into the early stages of the master's dissertation (Social Sciences and Humanities) at a UK university. I present a contrastive process-oriented analysis of two students' experiences on different courses, extracted from a 13-month ethnographic study in which…

First Measurement of the Muon Anti-Neutrino Charged Current Quasielastic Double-Differential Cross-Section

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grange, Joseph M.

2013-01-01

This dissertation presents the first measurement of the muon antineutrino charged current quasi-elastic double-differential cross section. These data significantly extend the knowledge of neutrino and antineutrino interactions in the GeV range, a region that has recently come under scrutiny due to a number of conflicting experimental results. To maximize the precision of this measurement, three novel techniques were employed to measure the neutrino background component of the data set. Representing the first measurements of the neutrino contribution to an accelerator-based antineutrino beam in the absence of a magnetic field, the successful execution of these techniques carry implications for current andmore » future neutrino experiments.« less

Soft-Templating Synthesis of Mesoporous Silica-Based Materials for Environmental Applications

NASA Astrophysics Data System (ADS)

Gunathilake, Chamila Asanka

Dissertation research is mainly focus on: 1) the development of mesoporous silica materials with organic pendant and bridging groups (isocyanurate, amidoxime, benzene) and incorporated metal (aluminum, zirconium, calcium, and magnesium) species for high temperature carbon dioxide (CO2) sorption, 2) phosphorous-hydroxy functionalized mesoporous silica materials for water treatment, and 3) amidoxime-modified ordered mesoporous silica materials for uranium sorption under seawater conditions. The goal is to design composite materials for environmental applications with desired porosity, surface area, and functionality by selecting proper metal oxide precursors, organosilanes, tetraethylorthosilicate, (TEOS), and block copolymer templates and by adjusting synthesis conditions. The first part of dissertation presents experimental studies on the merge of aluminum, zirconium, calcium, and magnesium oxides with mesoporous silica materials containing organic pendant (amidoxime) and bridging groups (isocyanurate, benzene) to obtain composite sorbents for CO2 sorption at ambient (0-25 °C) and elevated (60-120 °C) temperatures. These studies indicate that the aforementioned composite sorbents are fairly good for CO2 capture at 25 °C via physisorption mechanism and show a remarkably high affinity toward CO2 chemisorption at 60-120 °C. The second part of dissertation is devoted to silica-based materials with organic functionalities for removal of heavy metal ions such as lead from contaminated water and for recovery of metal ions such as uranium from seawater. First, ordered mesoporous organosilica (OMO) materials with diethylphosphatoethyl and hydroxyphosphatoethyl surface groups were examined for Pb2+ adsorption and showed unprecedented adsorption capacities up to 272 mg/g and 202 mg/g, respectively However, the amidoxime-modified OMO materials were explored for uranium extraction under seawater conditions and showed remarkable capacities reaching 57 mg of uranium per gram of adsorbent.

Design synthesis and optimization of permanent magnet synchronous machines based on computationally-efficient finite element analysis

NASA Astrophysics Data System (ADS)

Sizov, Gennadi Y.

In this dissertation, a model-based multi-objective optimal design of permanent magnet ac machines, supplied by sine-wave current regulated drives, is developed and implemented. The design procedure uses an efficient electromagnetic finite element-based solver to accurately model nonlinear material properties and complex geometric shapes associated with magnetic circuit design. Application of an electromagnetic finite element-based solver allows for accurate computation of intricate performance parameters and characteristics. The first contribution of this dissertation is the development of a rapid computational method that allows accurate and efficient exploration of large multi-dimensional design spaces in search of optimum design(s). The computationally efficient finite element-based approach developed in this work provides a framework of tools that allow rapid analysis of synchronous electric machines operating under steady-state conditions. In the developed modeling approach, major steady-state performance parameters such as, winding flux linkages and voltages, average, cogging and ripple torques, stator core flux densities, core losses, efficiencies and saturated machine winding inductances, are calculated with minimum computational effort. In addition, the method includes means for rapid estimation of distributed stator forces and three-dimensional effects of stator and/or rotor skew on the performance of the machine. The second contribution of this dissertation is the development of the design synthesis and optimization method based on a differential evolution algorithm. The approach relies on the developed finite element-based modeling method for electromagnetic analysis and is able to tackle large-scale multi-objective design problems using modest computational resources. Overall, computational time savings of up to two orders of magnitude are achievable, when compared to current and prevalent state-of-the-art methods. These computational savings allow one to expand the optimization problem to achieve more complex and comprehensive design objectives. The method is used in the design process of several interior permanent magnet industrial motors. The presented case studies demonstrate that the developed finite element-based approach practically eliminates the need for using less accurate analytical and lumped parameter equivalent circuit models for electric machine design optimization. The design process and experimental validation of the case-study machines are detailed in the dissertation.

Microwave-Assisted Ignition for Improved Internal Combustion Engine Efficiency

NASA Astrophysics Data System (ADS)

DeFilippo, Anthony Cesar

The ever-present need for reducing greenhouse gas emissions associated with transportation motivates this investigation of a novel ignition technology for internal combustion engine applications. Advanced engines can achieve higher efficiencies and reduced emissions by operating in regimes with diluted fuel-air mixtures and higher compression ratios, but the range of stable engine operation is constrained by combustion initiation and flame propagation when dilution levels are high. An advanced ignition technology that reliably extends the operating range of internal combustion engines will aid practical implementation of the next generation of high-efficiency engines. This dissertation contributes to next-generation ignition technology advancement by experimentally analyzing a prototype technology as well as developing a numerical model for the chemical processes governing microwave-assisted ignition. The microwave-assisted spark plug under development by Imagineering, Inc. of Japan has previously been shown to expand the stable operating range of gasoline-fueled engines through plasma-assisted combustion, but the factors limiting its operation were not well characterized. The present experimental study has two main goals. The first goal is to investigate the capability of the microwave-assisted spark plug towards expanding the stable operating range of wet-ethanol-fueled engines. The stability range is investigated by examining the coefficient of variation of indicated mean effective pressure as a metric for instability, and indicated specific ethanol consumption as a metric for efficiency. The second goal is to examine the factors affecting the extent to which microwaves enhance ignition processes. The factors impacting microwave enhancement of ignition processes are individually examined, using flame development behavior as a key metric in determining microwave effectiveness. Further development of practical combustion applications implementing microwave-assisted spark technology will benefit from predictive models which include the plasma processes governing the observed combustion enhancement. This dissertation documents the development of a chemical kinetic mechanism for the plasma-assisted combustion processes relevant to microwave-assisted spark ignition. The mechanism includes an existing mechanism for gas-phase methane oxidation, supplemented with electron impact reactions, cation and anion chemical reactions, and reactions involving vibrationally-excited and electronically-excited species. Calculations using the presently-developed numerical model explain experimentally-observed trends, highlighting the relative importance of pressure, temperature, and mixture composition in determining the effectiveness of microwave-assisted ignition enhancement.

Implementing Mapping the Beat in the 8th Grade

ERIC Educational Resources Information Center

Richardson, Ronald Craig

2010-01-01

This article is based on a doctoral dissertation study, "Expanding Geographic Understanding in Grade 8 Social Studies Classes through Integration of Geography, Music, and History: A QuasiExperimental Study" that took place in a high-achieving, suburban middle school in Southern California. The study compared learning as a result of nine…

Exhaustivity in Questions & Clefts; and the Quantifier Connection: A Study in German and English

ERIC Educational Resources Information Center

Heizmann, Tanja

2012-01-01

This thesis investigates children's acquisition of exhaustivity across four structures: quantifiers, single questions, multiple questions and clefts. Two languages, English and German, are probed. Exhaustivity needs some sort of plural set to be mentioned without leaving out a member of that set. This dissertation provides experimental data…

National and Global: A History of Scholars' Experiences with Research at the University of Dar Es Salaam, Tanzania (1961-Present)

ERIC Educational Resources Information Center

Jamison, Amy J.

2010-01-01

In this dissertation, I draw on research carried out at the University of Dar es Salaam (UDSM), Tanzania in 2008 to examine Tanzanian academics' experience with research throughout the history of this institution. This dissertation is designed as an historical case study and investigates how economic and political changes in Tanzania's…

A Benefit/Cost Analysis of Three Student Enrollment Behaviors at a Community College: Dropout, Transfer and Completion of an Associate's Degree/Certificate

ERIC Educational Resources Information Center

Stuart, G. Robert

2010-01-01

This dissertation seeks to increase our understanding of the factors that lead to student success at community colleges. Using data on a cohort of students enrolled at a two-year college, this dissertation presents the results of a longitudinal analysis. Citing the results of several persistence studies as well as the literature on…

Light Scattering Studies of Defects in Nematic/Twist-Bend Liquid Crystals and Layer Fluctuations in Free-Standing Smectic Membranes

NASA Astrophysics Data System (ADS)

Pardaev, Shokir A.

This research described in this dissertation comprises three experimental topics and includes the development of an appropriate theoretical framework to understand the various observations in each. In the first part, we present results from angle-resolved second-harmonic light scattering measurements on three different classes of thermotropic nematic liquid crystals: polar and non-polar rodlike compounds, and a bent-core compound. We analyze the data in terms of the "flexoelectric" polarization induced by distortions of the nematic director field around topological defects known as inversion walls, which are analogous to Neel walls in magnetic spin systems and which often exhibit a closed loop morphology in nematic systems. The second part of this dissertation explores the possible existence of a helical polarization field in the nematic twist-bend (NTB) phase of dimeric liquid crystals, utilizing a similar nonlinear light scattering approach. The NTB phase is characterized by a heliconical winding of the local molecular long axis (director) with a remarkably short, nanoscale pitch. According to theoretical conjecture, a helical electric polarization field accompanies this director modulation, but, due to the short pitch, presents a significant challenge for experimental detection. Our study focuses on topological defects, classified as parabolic focal conics, in two achiral, NTB-forming liquid crystals. These defects generate distortions of the polarization field on sufficiently long (micron) lengths to enable a confirmation of the existence of polar structure. We analyze our results with a coarse-grained free energy density that combines a Landau-deGennes expansion of the polarization field, the elastic energy of a nematic, and a bilinear coupling between the two. The last part of the dissertation focuses on the layer dynamics of thin, free-standing membranes of a smectic-A liquid crystal, with a particular consideration of the surface (interfacial) parameters that control these dynamics. We utilize photon correlation spectroscopy to probe the contributions of distinct under- and overdamped processes to the membrane motion. According to hydrodynamic theory, the frequency and damping rate of underdamped layer motion should scale with scattering vector in a manner controlled by the relative magnitude of a surface elastic constant, which is associated with gradients in surface tension, as well as by the average surface tension. In addition, the damping in very thin films is predicted to be quite sensitive to the presence of an atmosphere surrounding the film. A distinct, overdamped mode, observable in sufficiently thick films, is also predicted to couple to the layer motion. We present results on these dynamical modes and their dispersion and demonstrate their consistency with the hydrodynamic theory subject to appropriate surface boundary conditions.

The development of a volume element model for energy systems engineering and integrative thermodynamic optimization

NASA Astrophysics Data System (ADS)

Yang, Sam

The dissertation presents the mathematical formulation, experimental validation, and application of a volume element model (VEM) devised for modeling, simulation, and optimization of energy systems in their early design stages. The proposed model combines existing modeling techniques and experimental adjustment to formulate a reduced-order model, while retaining sufficient accuracy to serve as a practical system-level design analysis and optimization tool. In the VEM, the physical domain under consideration is discretized in space using lumped hexahedral elements (i.e., volume elements), and the governing equations for the variable of interest are applied to each element to quantify diverse types of flows that cross it. Subsequently, a system of algebraic and ordinary differential equations is solved with respect to time and scalar (e.g., temperature, relative humidity, etc.) fields are obtained in both spatial and temporal domains. The VEM is capable of capturing and predicting dynamic physical behaviors in the entire system domain (i.e., at system level), including mutual interactions among system constituents, as well as with their respective surroundings and cooling systems, if any. The VEM is also generalizable; that is, the model can be easily adapted to simulate and optimize diverse systems of different scales and complexity and attain numerical convergence with sufficient accuracy. Both the capability and generalizability of the VEM are demonstrated in the dissertation via thermal modeling and simulation of an Off-Grid Zero Emissions Building, an all-electric ship, and a vapor compression refrigeration (VCR) system. Furthermore, the potential of the VEM as an optimization tool is presented through the integrative thermodynamic optimization of a VCR system, whose results are used to evaluate the trade-offs between various objective functions, namely, coefficient of performance, second law efficiency, pull-down time, and refrigerated space temperature, in both transient and steady-state operations.

Real-Time Condition Monitoring and Fault Diagnosis of Gear Train Systems Using Instantaneous Angular Speed (IAS) Analysis

NASA Astrophysics Data System (ADS)

Sait, Abdulrahman S.

This dissertation presents a reliable technique for monitoring the condition of rotating machinery by applying instantaneous angular speed (IAS) analysis. A new analysis of the effects of changes in the orientation of the line of action and the pressure angle of the resultant force acting on gear tooth profile of spur gear under different levels of tooth damage is utilized. The analysis and experimental work discussed in this dissertation provide a clear understating of the effects of damage on the IAS by analyzing the digital signals output of rotary incremental optical encoder. A comprehensive literature review of state of the knowledge in condition monitoring and fault diagnostics of rotating machinery, including gearbox system is presented. Progress and new developments over the past 30 years in failure detection techniques of rotating machinery including engines, bearings and gearboxes are thoroughly reviewed. This work is limited to the analysis of a gear train system with gear tooth surface faults utilizing angular motion analysis technique. Angular motion data were acquired using an incremental optical encoder. Results are compared to a vibration-based technique. The vibration data were acquired using an accelerometer. The signals were obtained and analyzed in the phase domains using signal averaging to determine the existence and position of faults on the gear train system. Forces between the mating teeth surfaces are analyzed and simulated to validate the influence of the presence of damage on the pressure angle and the IAS. National Instruments hardware is used and NI LabVIEW software code is developed for real-time, online condition monitoring systems and fault detection techniques. The sensitivity of optical encoders to gear fault detection techniques is experimentally investigated by applying IAS analysis under different gear damage levels and different operating conditions. A reliable methodology is developed for selecting appropriate testing/operating conditions of a rotating system to generate an alarm system for damage detection.

The Meaning of Relationships for Student Agency in Soka Education: Exploring the Lived Experiences and Application of Daisaku Ikeda's Value-Creating Philosophy through Narrative Inquiry

ERIC Educational Resources Information Center

Nagashima, Julie Takako

2016-01-01

This dissertation examines a pedagogy called Soka education that was founded in early 20th century Japan. Specifically, this dissertation offers an empirical and conceptual study that examines the application of Soka education in present day. After examining the historical and political context of Soka education, I explicate on Ikeda's (1928- )…

Analysis of the Database of Theses and Dissertations from DME/UFSCAR about Astronomy Education

NASA Astrophysics Data System (ADS)

Rodrigues Ferreira, Orlando; Voelzke, Marcos Rincon

2013-11-01

The paper presents a brief analysis of the "Database of Theses and Dissertations about Astronomy Education" from the Department of Teaching Methodology (DME) of the Federal University of São Carlos(UFSCar). This kind of study made it possible to develop new analysis and statistical data, as well as to conduct a rating of Brazilian institutions that produce academic work in the area.

Development of a Resource Manager Framework for Adaptive Beamformer Selection

DTIC Science & Technology

2013-12-27

DEVELOPMENT OF A RESOURCE MANAGER FRAMEWORK FOR ADAPTIVE BEAMFORMER SELECTION DISSERTATION Jeremy P. Stringer, Major, USAF AFIT-ENG-DS-13-D-01...Force, the United States Department of Defense or the United States Government. AFIT-ENG-DS-13-D-01 DEVELOPMENT OF A RESOURCE MANAGER FRAMEWORK FOR...ADAPTIVE BEAMFORMER SELECTION DISSERTATION Presented to the Faculty Graduate School of Engineering and Management Air Force Institute of Technology Air

Liquid crystal interfaces: Experiments, simulations and biosensors

NASA Astrophysics Data System (ADS)

Popov, Piotr

Interfacial phenomena are ubiquitous and extremely important in various aspects of biological and industrial processes. For example, many liquid crystal applications start by alignment with a surface. The underlying mechanisms of the molecular organization of liquid crystals at an interface are still under intensive study and continue to be important to the display industry in order to develop better and/or new display technology. My dissertation research has been devoted to studying how complex liquid crystals can be guided to organize at an interface, and to using my findings to develop practical applications. Specifically, I have been working on developing biosensors using liquid-crystal/surfactant/lipid/protein interactions as well as the alignment of low-symmetry liquid crystals for potential new display and optomechanical applications. The biotechnology industry needs better ways of sensing biomaterials and identifying various nanoscale events at biological interfaces and in aqueous solutions. Sensors in which the recognition material is a liquid crystal naturally connects the existing knowledge and experience of the display and biotechnology industries together with surface and soft matter sciences. This dissertation thus mainly focuses on the delicate phenomena that happen at liquid interfaces. In the introduction, I start by defining the interface and discuss its structure and the relevant interfacial forces. I then introduce the general characteristics of biosensors and, in particular, describe the design of biosensors that employ liquid crystal/aqueous solution interfaces. I further describe the basic properties of liquid crystal materials that are relevant for liquid crystal-based biosensing applications. In CHAPTER 2, I describe the simulation methods and experimental techniques used in this dissertation. In CHAPTER 3 and CHAPTER 4, I present my computer simulation work. CHAPTER 3 presents insight of how liquid crystal molecules are aligned by hydrocarbon surfaces at the atomic level. I show that the vertical alignment of a rod-like liquid crystal molecule first requires its insertion into the alignment layer. In CHAPTER 4, I investigate the Brownian behavior of a tracer molecule at an oil/water interface and explain the experimentally-observed anomaly of its increased mobility. Following my molecular dynamics simulation studies of liquid interfaces, I continue my work in CHAPTER 5 with experimental research. I employ the high sensitivity of liquid crystal alignment to the presence of amphiphiles adsorbed to the liquid crystal surface from water for potential biosensor applications. I propose a more accurate method of sensing using circular polarization and spectrophotometry. In CHAPTER 6, I investigate if cholesteric and smectic liquid crystals can potentially offer new modes of biosensing. In CHAPTER 7, I describe preliminary results toward constructing a liquid crystal biosensor platform with capabilities of specific sensitivity using proteins and antibodies. Finally in CHAPTER 8, I summarize the findings of my studies and research and suggest possible future experiments to further advance our knowledge in interfacial science for future applications.

A Comparison Study between a Traditional and Experimental Program.

ERIC Educational Resources Information Center

Dogan, Hamide

This paper is part of a dissertation defended in January 2001 as part of the author's Ph.D. requirement. The study investigated the effects of use of Mathematica, a computer algebra system, in learning basic linear algebra concepts, It was done by means of comparing two first year linear algebra classes, one traditional and one Mathematica…

A Study and Model of Machine-Like Indexing Behavior by Human Indexers.

ERIC Educational Resources Information Center

McAllister, Caryl

Although a large part of a document retrieval system's resources are devoted to indexing, the question of how people do subject indexing has been the subject of much conjecture and only a little experimentation. This dissertation examines the relationships between a document being indexed and the index terms assigned to that document in an attempt…

Applying AN Object-Oriented Database Model to a Scientific Database Problem: Managing Experimental Data at Cebaf.

NASA Astrophysics Data System (ADS)

Ehlmann, Bryon K.

Current scientific experiments are often characterized by massive amounts of very complex data and the need for complex data analysis software. Object-oriented database (OODB) systems have the potential of improving the description of the structure and semantics of this data and of integrating the analysis software with the data. This dissertation results from research to enhance OODB functionality and methodology to support scientific databases (SDBs) and, more specifically, to support a nuclear physics experiments database for the Continuous Electron Beam Accelerator Facility (CEBAF). This research to date has identified a number of problems related to the practical application of OODB technology to the conceptual design of the CEBAF experiments database and other SDBs: the lack of a generally accepted OODB design methodology, the lack of a standard OODB model, the lack of a clear conceptual level in existing OODB models, and the limited support in existing OODB systems for many common object relationships inherent in SDBs. To address these problems, the dissertation describes an Object-Relationship Diagram (ORD) and an Object-oriented Database Definition Language (ODDL) that provide tools that allow SDB design and development to proceed systematically and independently of existing OODB systems. These tools define multi-level, conceptual data models for SDB design, which incorporate a simple notation for describing common types of relationships that occur in SDBs. ODDL allows these relationships and other desirable SDB capabilities to be supported by an extended OODB system. A conceptual model of the CEBAF experiments database is presented in terms of ORDs and the ODDL to demonstrate their functionality and use and provide a foundation for future development of experimental nuclear physics software using an OODB approach.

Design of SC walls and slabs for impulsive loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varma, Amit H.

2015-11-11

Reinforced concrete (RC) structures have historically been the preferred choice for blast resistant structures because of their mass and the ductility provided by steel reinforcement. Steel-plate composite (SC) walls are a viable alternative to RC for protecting the infrastructure against explosive threats. SC structures consist of two steel faceplates with a plain concrete core between them. The steel faceplates are anchored to the concrete using stud anchors and connected to each other using tie bars. SC structures provide mass from the concrete infill and ductility from the continuous external steel faceplates. This dissertation presents findings and recommendations from experimental andmore » analytical investigations of the performance of SC walls subjected to far-field blast loads.« less

[The concept of transcultural nursing: the analysis of its development in a Master degree dissertation].

PubMed

Queiroz, M V; Pagliuca, L M

2001-01-01

This is an analytic-bibliographic study which analyzes the concept of nursing in Leininger's Theory and the conceptual development of Nursing presented in the master's degree dissertation chosen for this study. Barnum's model for the analysis and evaluation of theories (Barnum 1998) was used, in relation to the clarity and consistency of the concept, together with questions about Nursing. The group of statements presented in Leininger's transcultural nursing concept and in the dissertation shows what is the focus of nursing and the intrinsic relation to the process of looking after somebody, which must be developed coherently with culture. It also demonstrates that Nursing has a body of specific professional knowledge which guides the care for the client, valuing one's individuality, subjectivity and way of seeing the world. The study made it possible to validate concepts taken from the Theory of Universality and Cultural Diversity of caring and their use in the research according to the analyzed criteria.

Characterization and Detection of Vector-borne Diseases in Endemic Transmission Areas

DTIC Science & Technology

2016-01-18

research in her laboratory and for introducing me to her many collaborators and friends all over the world. Thanks to all present and former members of...Luckhart at the University of California Davis for feedback on my dissertation research and manuscripts. Second, I would like to thank Dr. Jon...and mortality due to vector-borne diseases globally. The research described in this dissertation aims to improve detection methods for both the vector

Heat Transfer in Pebble-Bed Nuclear Reactor Cores Cooled by Fluoride Salts

NASA Astrophysics Data System (ADS)

Huddar, Lakshana Ravindranath

With electricity demand predicted to rise by more than 50% within the next 20 years and a burgeoning world population requiring reliable emissions-free base-load electricity, can we design advanced nuclear reactors to help meet this challenge? At the University of California, Berkeley (UCB) Fluoride-salt-cooled High Temperature Reactors (FHR) are currently being investigated. FHRs are designed with better safety and economic characteristics than conventional light water reactors (LWR) currently in operation. These reactors operate at high temperature and low pressure making them more efficient and safer than LWRs. The pebble-bed FHR (PB-FHR) variant includes an annular nuclear reactor core that is filled with randomly packed pebble fuel. It is crucial to characterize the heat transfer within this unique geometry as this informs the safety limits of the reactor. The work presented in this dissertation focused on furthering the understanding of heat transfer in pebble-bed nuclear reactor cores using fluoride salts as a coolant. This was done through experimental, analytical and computational techniques. A complex nuclear system with a coolant that has never previously been in commercial use requires experimental data that can directly inform aspects of its design. It is important to isolate heat transfer phenomena in order to understand the underlying physics in the context of the PB-FHR, as well as to make decisions about further experimental work that needs to be done in support of developing the PB-FHR. Certain organic oils can simulate the heat transfer behaviour of the fluoride salt if relevant non-dimensional parameters are matched. The advantage of this method is that experiments can be done at a much lower temperature and at a smaller geometric scale compared to FHRs, thereby lowering costs. In this dissertation, experiments were designed and performed to collect data demonstrating similitude. The limitations of these experiments were also elucidated by underlining key distortions between the experimental and the prototypical conditions. This dissertation is broadly split into four parts. Firstly, the heat transfer phenomenology in the PB-FHR core was outlined. Although the viscous dissipation term and the thermal diffusion term (including thermal dispersion) were similar in magnitude, they were overshadowed by the advection term which was about 104 times bigger during normal operation and 105 times bigger during accident transients in which natural circulation becomes the main mode of fluid flow. Thus it is safe to neglect the viscous dissipation and the thermal diffusion terms in the PB-FHR core without a significant loss of accuracy. Secondly, separate effects tests (SET) were performed using simulant oils, and the results were compared to the prototypical conditions using flinak as the fluoride salt. The main purpose of these experiments was to study natural convection heat transfer and identify any distortions between the two cases. An isolated copper sphere was immersed in flinak and a parallel experiment was performed using simulant oil. A large discrepancy between the flinak and the oil was noted, due to distortions from assuming quasi-steady state conditions. A steady state experiment using a cylindrical heater immersed in oil was also performed, and the results compared to a similar experiment done at Oak Ridge National Laboratory (ORNL) using flinak. The Nusselt numbers matched within 10% for laminar flows. This supports the conclusion that natural convection similitude does exist for oils used in scaled experiments, allowing natural convection data to be used for for FHR and MSR modeling. This is important, due to the lack of significant experimental data showing natural convection in fluoride salts, so these SETs add to the overall understanding of their heat transfer properties. With the knowledge of the distortions between the oil and the salt, an experiment to measure heat transfer coefficients within a pebble-bed test section was designed, constructed and performed. Oil was pumped through a test section filled with randomly packed copper spheres. The temperature of the oil was pulsed at a constant frequency, which caused a temperature difference between the pebbles and the oil. An excellent match was found between the measured heat transfer coefficients and the literature. This data provides an essential closure parameter for multiphysics modeling of the PB-FHR. Using frequency response techniques in scaled experiments is an innovative approach for extracting dynamic responses to coolant-structure interactions. Finally, an integrated model of the passive decay heat removal system was presented using Flownex and the simulations compared to experimental data. A good match was found with the data, which was within 14%. The work presented in this dissertation shows fundamental details on heat transfer in the PB-FHR core using experimental data and simulations, leading us closer to developing advanced nuclear reactors that can later be commercialized. Advanced nuclear reactors such as the PB-FHR have immense potential in reducing greenhouse gas emissions and combating climate change while being exceedingly safe and providing reliable electricity.

Heat transfer and flow in solar energy and bioenergy systems

NASA Astrophysics Data System (ADS)

Xu, Ben

The demand for clean and environmentally benign energy resources has been a great concern in the last two decades. To alleviate the associated environmental problems, reduction of the use of fossil fuels by developing more cost-effective renewable energy technologies becomes more and more significant. Among various types of renewable energy sources, solar energy and bioenergy take a great proportion. This dissertation focuses on the heat transfer and flow in solar energy and bioenergy systems, specifically for Thermal Energy Storage (TES) systems in Concentrated Solar Power (CSP) plants and open-channel algal culture raceways for biofuel production. The first part of this dissertation is the discussion about mathematical modeling, numerical simulation and experimental investigation of solar TES system. First of all, in order to accurately and efficiently simulate the conjugate heat transfer between Heat Transfer Fluid (HTF) and filler material in four different solid-fluid TES configurations, formulas of an e?ective heat transfer coe?cient were theoretically developed and presented by extending the validity of Lumped Capacitance Method (LCM) to large Biot number, as well as verifications/validations to this simplified model. Secondly, to provide design guidelines for TES system in CSP plant using Phase Change Materials (PCM), a general storage tank volume sizing strategy and an energy storage startup strategy were proposed using the enthalpy-based 1D transient model. Then experimental investigations were conducted to explore a novel thermal storage material. The thermal storage performances were also compared between this novel storage material and concrete at a temperature range from 400 °C to 500 °C. It is recommended to apply this novel thermal storage material to replace concrete at high operating temperatures in sensible heat TES systems. The second part of this dissertation mainly focuses on the numerical and experimental study of an open-channel algae culture raceway for biofuel production. According to the proposed flow field design of ARID-HV algal raceway, experiments and numerical simulation have been conducted to understand the enhancement of flow mixing in the flow field of ARID-HV raceway by cutting slots on top of the dam near the dead zones. A new method was proposed to quantitatively evaluate the flow mixing by using the statistics of temporal and spatial distribution of the massless fluid particles (centered in each cell at the inlet surface) in the raceway collecting the data of path-lines of fluid particles from CFD results. It is hoped that this method can be applied to assist the algal raceway flow field design as well as other engineering applications. The third part introduces the details about the construction work of a high temperature molten salt test loop. Because of the limited operating temperature of conventional synthetic oils, in order to obtain higher energy conversion efficiency, higher operating temperature is always desirable in a CSP plant which leads to the requirement of new generation of HTF. Currently, a halide salt eutectic mixture (NaCl-KCl-ZnCl2) as a potential HTF for future CSP applications has been proposed by a multi-institute research team, led by University of Arizona. The thermophysical properties of the halide eutectic salt have been measured. However, this new developed halide eutectic salt has not been tested in a circulating loop at a high operating temperature for the measurement of heat transfer coefficient. It is a significant effort to build such a test system due to extremely high operating temperature. As a consequence, in the third part of this dissertation, details about the design of the lab-scale test system and all the equipment items will be introduced. The investigations included in this dissertation for the heat transfer and flow in solar energy and bioenergy systems are of particular interest to the renewable energy engineering community. It is expected that the proposed methods can provide useful information for engineers and researchers.

The Effects of Magnetic Nozzle Configurations on Plasma Thrusters

NASA Technical Reports Server (NTRS)

Turchi, P. J.

1997-01-01

Over the course of eight years, the Ohio State University has performed research in support of electric propulsion development efforts at the NASA Lewis Research Center, Cleveland, OH. This research has been largely devoted to plasma propulsion systems including MagnetoPlasmaDynamic (MPD) thrusters with externally-applied, solenoidal magnetic fields, hollow cathodes, and Pulsed Plasma Microthrusters (PPT's). Both experimental and theoretical work has been performed, as documented in four master's theses, two doctoral dissertations, and numerous technical papers. The present document is the final report for the grant period 5 December 1987 to 31 December 1995, and summarizes all activities. Detailed discussions of each area of activity are provided in appendices: Appendix 1 - Experimental studies of magnetic nozzle effects on plasma thrusters; Appendix 2 - Numerical modeling of applied-field MPD thrusters; Appendix 3 - Theoretical and experimental studies of hollow cathodes; and Appendix 4 -Theoretical, numerical and experimental studies of pulsed plasma thrusters. Especially notable results include the efficacy of using a solenoidal magnetic field downstream of a plasma thruster to collimate the exhaust flow, the development of a new understanding of applied-field MPD thrusters (based on experimentally-validated results from state-of-the art, numerical simulation) leading to predictions of improved performance, an experimentally-validated, first-principles model for orificed, hollow-cathode behavior, and the first time-dependent, two-dimensional calculations of ablation-fed, pulsed plasma thrusters.

Theoretical and experimental investigation of the nonlinear dynamical trends of passively mode-locked quantum dot lasers

NASA Astrophysics Data System (ADS)

Raghunathan, Ravi

In recent years, passively mode-locked quantum dot lasers have shown great promise as compact, efficient and reliable pulsed sources of light for a range of precision and high performance applications, such as high bit-rate optical communications, diverse waveform generation, metrology, and clock distribution in high-performance computing (HPC) processors. For such applications, stable optical pulses with short picosecond pulse durations and multi-gigahertz repetition rates are required. In addition, a low pulse-to-pulse timing jitter is also necessary to prevent errors arising from the ambiguity between neighboring pulses. In order to optimize pulse quality in terms of optical characteristics such as pulse shape and pulse train behavior, as well as RF characteristics such as phase noise and timing jitter, understanding the nonlinear output dynamics of such devices is of critical importance, not only to get a sense of the regimes of operation where device output might be stable or unstable, but also to gain insight into the parameters that influence the output characteristics the most, and how they can be accessed and exploited to optimize design and performance for next generation applications. In this dissertation, theoretical and experimental studies have been combined to investigate the dynamical trends of two-section passively mode-locked quantum dot lasers. On the theoretical side, a novel numerical modeling scheme is presented as a powerful and versatile framework to study the nonlinear dynamics specific to a device, with device-specific parameters extracted over a range of operating conditions. The practical utility of this scheme is then demonstrated, first, in an analytical capability to interpret and explain dynamical trends observed in experiment, and subsequently, as a predictive tool to guide experiment to operate in a desired dynamical regime. Modeling results are compared to experimental findings where possible. Finally, optical feedback from an external reflector is experimentally studied as an additional control mechanism over the output dynamics of the device, and shown to enable invaluable insight into the behavior of the RF and optical spectra of the output. Together, the theoretical and experimental findings of this dissertation are shown to offer a systematic approach to understand, control and exploit the dynamical trends of passively mode-locked two-section quantum dot lasers.

Spectroscopic characterization of low dose rate brachytherapy sources

NASA Astrophysics Data System (ADS)

Beach, Stephen M.

The low dose rate (LDR) brachytherapy seeds employed in permanent radioactive-source implant treatments usually use one of two radionuclides, 125I or 103Pd. The theoretically expected source spectroscopic output from these sources can be obtained via Monte Carlo calculation based upon seed dimensions and materials as well as the bare-source photon emissions for that specific radionuclide. However the discrepancies resulting from inconsistent manufacturing of sources in comparison to each other within model groups and simplified Monte Carlo calculational geometries ultimately result in undesirably large uncertainties in the Monte Carlo calculated values. This dissertation describes experimentally attained spectroscopic outputs of the clinically used brachytherapy sources in air and in liquid water. Such knowledge can then be applied to characterize these sources by a more fundamental and metro logically-pure classification, that of energy-based dosimetry. The spectroscopic results contained within this dissertation can be utilized in the verification and benchmarking of Monte Carlo calculational models of these brachytherapy sources. This body of work was undertaken to establish a usable spectroscopy system and analysis methods for the meaningful study of LDR brachytherapy seeds. The development of a correction algorithm and the analysis of the resultant spectroscopic measurements are presented. The characterization of the spectrometer and the subsequent deconvolution of the measured spectrum to obtain the true spectrum free of any perturbations caused by the spectrometer itself is an important contribution of this work. The approach of spectroscopic deconvolution that was applied in this work is derived in detail and it is applied to the physical measurements. In addition, the spectroscopically based analogs to the LDR dosimetry parameters that are currently employed are detailed, as well as the development of the theory and measurement methods to arrive at these analogs. Several dosimetrically-relevant water-equivalent plastics were also investigated for their transmission properties within a liquid water environment, as well as in air. The framework for the accurate spectrometry of LDR sources is established as a result of this dissertation work. In addition to the measurement and analysis methods, this work presents the basic measured spectroscopic characteristics of each LDR seed currently in use in the clinic today.

Extending the Measurement Range of AN Optical Surface Profiler.

NASA Astrophysics Data System (ADS)

Cochran, Eugene Rowland, III

This dissertation investigates a method for extending the measurement range of an optical surface profiling instrument. The instrument examined in these experiments is a computer -controlled phase-modulated interference microscope. Because of its ability to measure surfaces with a high degree of vertical resolution as well as excellent lateral resolution, this instrument is one of the most favorable candidates for determining the microtopography of optical surfaces. However, the data acquired by the instrument are restricted to a finite lateral and vertical range. To overcome this restriction, the feasibility of a new testing technique is explored. By overlapping a series of collinear profiles the limited field of view of this instrument can be increased and profiles that contain longer surface wavelengths can be examined. This dissertation also presents a method to augment both the vertical and horizontal dynamic range of the surface profiler by combining multiple subapertures and two-wavelength techniques. The theory, algorithms, error sources, and limitations encountered when concatenating a number of profiles are presented. In particular, the effects of accumulated piston and tilt errors on a measurement are explored. Some practical considerations for implementation and integration into an existing system are presented. Experimental findings and results of Monte Carlo simulations are also studied to explain the effects of random noise, lateral position errors, and defocus across the CCD array on measurement results. These results indicate the extent to which the field of view of the profiler may be augmented. A review of current methods of measuring surface topography is included, to provide for a more coherent text, along with a summary of pertinent measurement parameters for surface characterization. This work concludes with recommendations for future work that would make subaperture -testing techniques more reliable for measuring the microsurface structure of a material over an extended region.

Applications of Atomic Systems in Quantum Simulation, Quantum Computation and Topological Phases of Matter

NASA Astrophysics Data System (ADS)

Wang, Shengtao

The ability to precisely and coherently control atomic systems has improved dramatically in the last two decades, driving remarkable advancements in quantum computation and simulation. In recent years, atomic and atom-like systems have also been served as a platform to study topological phases of matter and non-equilibrium many-body physics. Integrated with rapid theoretical progress, the employment of these systems is expanding the realm of our understanding on a range of physical phenomena. In this dissertation, I draw on state-of-the-art experimental technology to develop several new ideas for controlling and applying atomic systems. In the first part of this dissertation, we propose several novel schemes to realize, detect, and probe topological phases in atomic and atom-like systems. We first theoretically study the intriguing properties of Hopf insulators, a peculiar type of topological insulators beyond the standard classification paradigm of topological phases. Using a solid-state quantum simulator, we report the first experimental observation of Hopf insulators. We demonstrate the Hopf fibration with fascinating topological links in the experiment, showing clear signals of topological phase transitions for the underlying Hamiltonian. Next, we propose a feasible experimental scheme to realize the chiral topological insulator in three dimensions. They are a type of topological insulators protected by the chiral symmetry and have thus far remained unobserved in experiment. We then introduce a method to directly measure topological invariants in cold-atom experiments. This detection scheme is general and applicable to probe of different topological insulators in any spatial dimension. In another study, we theoretically discover a new type of topological gapless rings, dubbed a Weyl exceptional ring, in three-dimensional dissipative cold atomic systems. In the second part of this dissertation, we focus on the application of atomic systems in quantum computation and simulation. Trapped atomic ions are one of the leading platforms to build a scalable, universal quantum computer. The common one-dimensional setup, however, greatly limits the system's scalability. By solving the critical problem of micromotion, we propose a two-dimensional architecture for scalable trapped-ion quantum computation. Hamiltonian tomography for many-body quantum systems is essential for benchmarking quantum computation and simulation. By employing dynamical decoupling, we propose a scalable scheme for full Hamiltonian tomography. The required number of measurements increases only polynomially with the system size, in contrast to an exponential scaling in common methods. Finally, we work toward the goal of demonstrating quantum supremacy. A number of sampling tasks, such as the boson sampling problem, have been proposed to be classically intractable under mild assumptions. An intermediate quantum computer can efficiently solve the sampling problem, but the correct operation of the device is not known to be classically verifiable. Toward practical verification, we present an experimental friendly scheme to extract useful and robust information from the quantum boson samplers based on coarse-grained measurements. In a separate study, we introduce a new model built from translation-invariant Ising-interacting spins. This model possesses several advantageous properties, catalyzing the ultimate experimental demonstration of quantum supremacy.

Summer Reading Loss: A Mixed-Methods Study of Parent Development and Home-Based Summer Reading

ERIC Educational Resources Information Center

Blanton, Morgan V.

2013-01-01

This dissertation utilized a mixed-methods, quasi-experimental design to investigate the impact of parent development on rising third graders' summer reading losses as measured by the difference in May and August oral reading fluency scores. Title I parents and students from three schools in a rural North Carolina school district participated in a…

Reading Intervention with K-4 Struggling Readers: The Effect of Using Minimally Trained Tutors in One Inner-City Public School

ERIC Educational Resources Information Center

Lipsey, Tammy

2010-01-01

The purpose of this quasi-experimental study was to evaluate the effectiveness of an early reading intervention method designed for students who were in need of extra help in reading. The early reading intervention (tutoring) was conducted for Kindergarten through fourth grade students. Specifically, this dissertation investigated the question: To…

Theoretical and Computational Studies of Condensed-Phase Phenomena: The Origin of Biological Homochirality, and the Liquid-Liquid Phase Transition in Network-Forming Fluids

NASA Astrophysics Data System (ADS)

Ricci, Francesco

This dissertation describes theoretical and computational studies of the origin of biological homochirality, and the existence of a liquid-liquid phase transition in pure-component network-forming fluids. A common theme throughout these studies is the use of sophisticated computer simulation and statistical mechanics techniques to study complex condensed-phase phenomena. In the first part of this dissertation, we use an elementary lattice model with molecular degrees of freedom, and satisfying microscopic reversibility, to investigate the effect of reaction reversibility on the evolution of stochastic symmetry breaking via autocatalysis and mutual inhibition in a closed system. We identify conditions under which the system's evolution towards racemic equilibrium becomes extremely slow, allowing for long-time persistence of a symmetry-broken state. We also identify a "monomer purification" mechanism, due to which a nearly homochiral state can persist for long times, even in the presence of significant reverse reaction rates. Order of magnitude estimates show that with reasonable physical parameters a symmetry broken state could persist over geologically-relevant time scales. In the second part of this dissertation, we study a chiral-symmetry breaking mechanism known as Viedma ripening. We develop a Monte Carlo model to gain further insights into the mechanisms capable of reproducing key experimental signatures associated with this phenomenon. We also provide a comprehensive investigation of how the model parameters impact the system's overall behavior. It is shown that size-dependent crystal solubility alone is insufficient to reproduce most experimental signatures, and that some form of a solid-phase chiral feedback mechanism (e.g., agglomeration) must be invoked in our model. In the third part of this dissertation, we perform rigorous free energy calculations to investigate the possibility of a liquid-liquid phase transition (LLPT) in the Stillinger-Weber (SW) model of silicon. A similar analysis is also presented for the generalized SW family of models by varying the "tetrahedrality" of the potential. Contrary to previously published findings, we do not find any evidence of the existence of an LLPT for SW silicon, nor for the generalized family of SW models over the range of parameters studied. Our results for the original parameterization of SW silicon are in semi-quantitative agreement with previous free energy calculations for this model, which were only provided at three state points. Explanations for the discrepancies between previous independent studies are provided, along with explicit demonstrations of how these discrepancies may have occurred. Finally, in the fourth part of this dissertation, we perform free energy calculations to demonstrate the existence of an LLPT in the Jagla potential. We also utilize finite-size scaling analysis to calculate the surface tension associated with the LLPT. In addition to the thermodynamics of the model, we investigate the relaxation times for density and bond-orientational order and show that, contrary to assertions in the literature, the characteristic relaxation time of bond-orientational order is not orders of magnitude slower than that of density. We compare our results for the Jagla model with those found in the literature for the ST2 model of water (which has also been rigorously shown to exhibit an LLPT) in order to emphasize key similarities and differences between two models that exhibit pure-component liquid-liquid phase separation.

Design, Construction, and Test of a 473 MHZ Four - Cavity Rfq.

NASA Astrophysics Data System (ADS)

Kazimi, Reza

1992-01-01

An RFQ accelerator using the new four-rod cavity design has been fabricated and successfully tested at Texas Accelerator Center. The RFQ is designed to accelerate a 10 mA H^- ion beam from 30 keV to 500 keV with the operating frequency of 473 MHz. This new type of RFQ structure not only promises simplicity of design, construction, and operation, but also can be manufactured to operate at higher frequencies than previously achieved by other four-rod type RFQs. Combination of simplicity and compactness due to higher operating frequencies (400 to 500 MHz) makes the design desirable for injector of proton accelerators, medical linear accelerators, and variety of other applications. This dissertation presents the steps I went through in inventing, developing, and experimentally testing this new RFQ design. First an introduction to accelerators is given, and the basic accelerator physics terminologies are defined. The principles of operations of the RFQs are described, and the theory behind new type of RFQ structure is explained. Then the beam dynamics and cavity design of the RFQ are presented. Finally, the mechanical design and construction procedure are discussed, and experimental results of rf tests and actual H ^- beam test are given.

Building Energy Modeling and Control Methods for Optimization and Renewables Integration

NASA Astrophysics Data System (ADS)

Burger, Eric M.

This dissertation presents techniques for the numerical modeling and control of building systems, with an emphasis on thermostatically controlled loads. The primary objective of this work is to address technical challenges related to the management of energy use in commercial and residential buildings. This work is motivated by the need to enhance the performance of building systems and by the potential for aggregated loads to perform load following and regulation ancillary services, thereby enabling the further adoption of intermittent renewable energy generation technologies. To increase the generalizability of the techniques, an emphasis is placed on recursive and adaptive methods which minimize the need for customization to specific buildings and applications. The techniques presented in this dissertation can be divided into two general categories: modeling and control. Modeling techniques encompass the processing of data streams from sensors and the training of numerical models. These models enable us to predict the energy use of a building and of sub-systems, such as a heating, ventilation, and air conditioning (HVAC) unit. Specifically, we first present an ensemble learning method for the short-term forecasting of total electricity demand in buildings. As the deployment of intermittent renewable energy resources continues to rise, the generation of accurate building-level electricity demand forecasts will be valuable to both grid operators and building energy management systems. Second, we present a recursive parameter estimation technique for identifying a thermostatically controlled load (TCL) model that is non-linear in the parameters. For TCLs to perform demand response services in real-time markets, online methods for parameter estimation are needed. Third, we develop a piecewise linear thermal model of a residential building and train the model using data collected from a custom-built thermostat. This model is capable of approximating unmodeled dynamics within a building by learning from sensor data. Control techniques encompass the application of optimal control theory, model predictive control, and convex distributed optimization to TCLs. First, we present the alternative control trajectory (ACT) representation, a novel method for the approximate optimization of non-convex discrete systems. This approach enables the optimal control of a population of non-convex agents using distributed convex optimization techniques. Second, we present a distributed convex optimization algorithm for the control of a TCL population. Experimental results demonstrate the application of this algorithm to the problem of renewable energy generation following. This dissertation contributes to the development of intelligent energy management systems for buildings by presenting a suite of novel and adaptable modeling and control techniques. Applications focus on optimizing the performance of building operations and on facilitating the integration of renewable energy resources.

[The first deontology dissertation in Croatia (Desković, 1943)].

PubMed

Segota, I

1995-01-01

The first Croatian deontological dissertation, and probably one of the oldest in Europe, was written in Vienna in 1843. It was also published there in German. Our medical historians discovered it 40 years ago. However, its contents have up to now been unknown to our scientific and broader community. The manuscript, titled "About Physician's Duties to the State and to his Fellow-Men" (in German original: Joseph Descovich, Ueber die Pflichten des Artzes, Gegen den Staat uind seine Mitmenschen), is the work of a Dalmatian physician from Omis, Dr. Josip Desković. Nowadays when medical ethics has evolved into an independent academic discipline, and is rapidly spreading on all continents, this dissertation indicates that historical roots of medical ethics in Croats are by more than 150 years older compared to some other European countries, e. g. Sweden. The author presents the content of the dissertation and analyses it from ethical and sociological viewpoints. He relates it to Hippocratic ethics as well as to contemporary medical ethics termed bioethics, which is steadily establishing itself in modern medicine.

Bibliometric analysis of theses and dissertations on prematurity in the Capes database.

PubMed

Pizzani, Luciana; Lopes, Juliana de Fátima; Manzini, Mariana Gurian; Martinez, Claudia Maria Simões

2012-01-01

To perform a bibliometric analysis of theses and dissertations on prematurity in the Capes database from 1987 to 2009. This is a descriptive study that used the bibliometric approach for the production of indicators of scientific production. Operationally, the methodology was developed in four steps: 1) construction of the theoretical framework; 2) data collection sourced from the abstracts of theses and dissertations available in the Capes Thesis Database which presented the issue of prematurity in the period 1987 to 2009; 3) organization, processing and construction of bibliometric indicators; 4) analysis and interpretation of results. Increase in the scientific literature on prematurity during the period 1987 to 2009; production is represented mostly by dissertations; the institution that received prominence was the Universidade de São Paulo. The studies are directed toward the low birth weight and very low birth weight preterm newborn, encompassing the social, biological and multifactorial causes of prematurity. There is a qualified, diverse and substantial scientific literature on prematurity developed in various graduate programs of higher education institutions in Brazil.

Intelligent systems approach for automated identification of individual control behavior of a human operator

NASA Astrophysics Data System (ADS)

Zaychik, Kirill B.

Acceptable results have been obtained using conventional techniques to model the generic human operator's control behavior. However, little research has been done in an attempt to identify an individual based on his/her control behavior. The main hypothesis investigated in this dissertation is that different operators exhibit different control behavior when performing a given control task. Furthermore, inter-person differences are manifested in the amplitude and frequency content of the non-linear component of the control behavior. Two enhancements to the existing models of the human operator, which allow personalization of the modeled control behavior, are presented in this dissertation. One of the proposed enhancements accounts for the "testing" control signals, which are introduced by an operator for more accurate control of the system and/or to adjust his/her control strategy. Such enhancement uses the Artificial Neural Network (ANN), which can be fine-tuned to model the "testing" control behavior of a given individual. The other model enhancement took the form of an equiripple filter (EF), which conditions the power spectrum of the control signal before it is passed through the plant dynamics block. The filter design technique uses Parks-McClellan algorithm, which allows parameterization of the desired levels of power at certain frequencies. A novel automated parameter identification technique (APID) was developed to facilitate the identification process of the parameters of the selected models of the human operator. APID utilizes a Genetic Algorithm (GA) based optimization engine called the Bit-climbing Algorithm (BCA). Proposed model enhancements were validated using the experimental data obtained at three different sources: the Manual Control Laboratory software experiments, Unmanned Aerial Vehicle simulation, and NASA Langley Research Center Visual Motion Simulator studies. Validation analysis involves comparison of the actual and simulated control activity signals. Validation criteria used in this dissertation is based on comparing Power Spectral Densities of the control signals against that of the Precision model of the human operator. This dissertation also addresses the issue of applying the proposed human operator model augmentation to evaluate the effectiveness of the motion feedback when simulating the actual pilot control behavior in a flight simulator. The proposed modeling methodology allows for quantitative assessments and prediction of the need for platform motion, while performing aircraft/pilot simulation studies.

Preservice elementary teachers learning of astronomy

NASA Astrophysics Data System (ADS)

Fidler, Chuck Gary

The dissertation presents a new approach for the study of preservice elementary teacher astronomy education. The approach suggests that learning astronomical concepts are facilitated by greater sophistication in scale perception and spatial-aptitude. This dissertation is underscored by the national call for elementary science education reform efforts and suggests certain strategies shown more effective for the development of accurate astronomical comprehension. The present research study describes how preservice elementary teachers conceptualize and communicate ideas about Space. Instead of assuming a universal mental conception of cosmic orientations and relationships, the dissertation claims that the perception of Space related dimensions vary among preservice elementary teachers. Furthermore, the dissertation suggests individual perceptions of the scale sizes and orientations of celestial systems have direct influences on mental models used to organize and communicate astronomical information. The development of inaccurate mental models of the scaled dimensions of Space may perpetuate the teacher-student cycle of misconception and naive-theory generation among children in elementary education settings. The ability to conceptualize the vast cosmos is facilitated by the minds ability to think about vast scales and orientations of celestial objects. The Earth-based perspective of astronomy education compels the learner to think about astronomical principles within imaginary frames of reference and across unfamiliar scaled dimensions. Therefore, mental astronomical model building is underscored by the perception of scale and cosmic spatiality. This study suggests these cognitive skill sets are interconnected and facilitate the learning of accurate astronomy principles; as well as play an important role when designing an astronomy education program for preservice elementary teachers. This research study is comprised of three separate standalone articles designed and formatted for journal submission. Chapter 1 outlines the intent, rationale, and design of the overall dissertation process and format. Chapter 2 describes an in-depth review of the specific astronomy curricula used for comparison by subsequent chapters and is not intended as a standalone article, but rather as an informative outline of events and activities to help the reader understand the differences of instruction between the two sections of sample populations. Chapter 3 uses qualitative interviews to explore the cosmic dimensions associated with learning of astronomy and finds diverse perceptions of astronomical scales may influence preservice teachers' mental organization of astronomical information. Chapter 4 further analyzes cosmic dimensions using quantitative analyses and specifically examines preservice teachers perceptions of scale and spatiality within the context of astronomy education. Findings from Chapter 4 show that perceptions of scale and spatiality are an interconnected set of learning skills which may greatly enhance the learning of astronomy. Chapter 5 describes how concepts of scale and spatiality may be operationalized within a secondary school science classroom in order to better understand the scaled distances of stars though an inquiry-based three-dimensional modeling activity. Chapter 6 briefly concludes the dissertation work. Due to the nature of this dissertation design, the conclusions chapter is quite succinct as previous chapters are designed with conclusions sections embedded within the body of the text as outlined by specific journal submission guidelines. These dissertation ideas are presented in a formal setting so that the various research undertakings can be studied and analyzed. Qualitative and quantitative analyses of research data are present to support the claims made in this study. The results of this research combine with features of previous research in order to advance our understanding of how preservice elementary teachers think about and learn astronomy.

Restructuring a Master's Degree Dissertation as a Patchwork Text.

ERIC Educational Resources Information Center

Maisch, Maire

2003-01-01

Describes the introduction of the Patchwork Text format into the dissertation on a Master's degree in Social Work. Discusses the rationale for rethinking the conventional dissertation and the "patches" making up the revised dissertation format. Draws upon completed dissertations of two students on the program to illustrate how the characteristics…

Dissertation Abstracts in Mathematics Education, 1983.

ERIC Educational Resources Information Center

Suydam, Marilyn N., Comp.

The dissertation abstracts in this compilation all appeared in "Dissertation Abstracts International" in 1983. The 300 dissertations cited in the annual listing of research in the July 1984 issue of the "Journal for Research in Mathematics Education" are included, as well as 55 dissertations which were located but could not be…

Mapping Topological Magnetization and Magnetic Skyrmions

NASA Astrophysics Data System (ADS)

Chess, Jordan J.

A 2014 study by the US Department of Energy conducted at Lawrence Berkeley National Laboratory estimated that U.S. data centers consumed 70 billion kWh of electricity. This represents about 1.8% of the total U.S. electricity consumption. Putting this in perspective 70 billion kWh of electricity is the equivalent of roughly 8 big nuclear reactors, or around double the nation's solar panel output. Developing new memory technologies capable of reducing this power consumption would be greatly beneficial as our demand for connectivity increases in the future. One newly emerging candidate for an information carrier in low power memory devices is the magnetic skyrmion. This magnetic texture is characterized by its specific non-trivial topology, giving it particle-like characteristics. Recent experimental work has shown that these skyrmions can be stabilized at room temperature and moved with extremely low electrical current densities. This rapidly developing field requires new measurement techniques capable of determining the topology of these textures at greater speed than previous approaches. In this dissertation, I give a brief introduction to the magnetic structures found in Fe/Gd multilayered systems. I then present newly developed techniques that streamline the analysis of Lorentz Transmission Electron Microscopy (LTEM) data. These techniques are then applied to further the understanding of the magnetic properties of these Fe/Gd based multilayered systems. This dissertation includes previously published and unpublished co-authored material.

Parameter estimation for lithium ion batteries

NASA Astrophysics Data System (ADS)

Santhanagopalan, Shriram

With an increase in the demand for lithium based batteries at the rate of about 7% per year, the amount of effort put into improving the performance of these batteries from both experimental and theoretical perspectives is increasing. There exist a number of mathematical models ranging from simple empirical models to complicated physics-based models to describe the processes leading to failure of these cells. The literature is also rife with experimental studies that characterize the various properties of the system in an attempt to improve the performance of lithium ion cells. However, very little has been done to quantify the experimental observations and relate these results to the existing mathematical models. In fact, the best of the physics based models in the literature show as much as 20% discrepancy when compared to experimental data. The reasons for such a big difference include, but are not limited to, numerical complexities involved in extracting parameters from experimental data and inconsistencies in interpreting directly measured values for the parameters. In this work, an attempt has been made to implement simplified models to extract parameter values that accurately characterize the performance of lithium ion cells. The validity of these models under a variety of experimental conditions is verified using a model discrimination procedure. Transport and kinetic properties are estimated using a non-linear estimation procedure. The initial state of charge inside each electrode is also maintained as an unknown parameter, since this value plays a significant role in accurately matching experimental charge/discharge curves with model predictions and is not readily known from experimental data. The second part of the dissertation focuses on parameters that change rapidly with time. For example, in the case of lithium ion batteries used in Hybrid Electric Vehicle (HEV) applications, the prediction of the State of Charge (SOC) of the cell under a variety of road conditions is important. An algorithm to predict the SOC in time intervals as small as 5 ms is of critical demand. In such cases, the conventional non-linear estimation procedure is not time-effective. There exist methodologies in the literature, such as those based on fuzzy logic; however, these techniques require a lot of computational storage space. Consequently, it is not possible to implement such techniques on a micro-chip for integration as a part of a real-time device. The Extended Kalman Filter (EKF) based approach presented in this work is a first step towards developing an efficient method to predict online, the State of Charge of a lithium ion cell based on an electrochemical model. The final part of the dissertation focuses on incorporating uncertainty in parameter values into electrochemical models using the polynomial chaos theory (PCT).

Microscale mechanical characterization of materials for extreme environments

NASA Astrophysics Data System (ADS)

Ozerinc, Sezer

Nanocrystalline metals are promising materials for applications that require outstanding strength and stability in extreme environments. Further improvements in the desirable mechanical properties of these materials require a better understanding of the relationship between their microstructure and grain boundary deformation behavior. Previous molecular dynamics simulations suggested that solute additions to grain boundaries can enhance the strength of nanocrystalline metals, but there has been a lack of experimental studies investigating this prediction. This dissertation presents mechanical and microstructural characterization of nanocrystalline Cu alloys and demonstrate that addition of Nb solutes to grain boundaries greatly enhances the strength of Cu. The measured hardness of Cu90Nb10 alloy is 5.6 GPa which is more than double the hardness of nanocrystalline pure Cu. Microstructural characterization through transmission electron microscopy and energy-dispersive X-ray spectroscopy on these alloys indicates a strong correlation between the grain boundary composition and the hardness. Variation of measured hardness with measured grain boundary composition is in very good agreement with previous molecular dynamics simulation predictions. The results of this work provide experimental evidence that grain boundary doping enhances the strength of nanocrystalline Cu far beyond that predicted by classical Hall-Petch strengthening and decreasing grain boundary energy through solute additions is the key to reaching theoretical strength in nanocrystalline metals. Irradiation induced creep is a deformation mechanism that takes place under combined stress and particle bombardment. Effective characterization of this phenomenon on nanostructured materials is crucial for the assessment of their potential use in next generation nuclear power plants. Direct measurements of irradiation induced creep under MeV-heavy ion bombardment have not been feasible until recently due to the requirements of micron-sized specimens, muN-level force sensitivity, and nm-level displacement sensitivity. A recently developed mechanical characterization technique, micropillar compression, has enabled the testing of miniaturized specimens; however, there has been no demonstration of the application of this technique to irradiation induced creep measurements. This dissertation presents the development of an in situ measurement apparatus for compression testing of micron-sized cylindrical specimens under MeV-heavy ion bombardment. The apparatus has a force resolution of 1 muN and a displacement resolution of 1 nm. The apparatus measured irradiation induced creep in four different amorphous materials and the findings clarified the significance of different creep mechanisms in these materials. In amorphous metals and amorphous Si, the measured irradiation induced fluidity is ≈ 3 dpa-1GPa-1 (dpa: displacements per atom). The measured fluidity is in excellent agreement with previous molecular dynamics simulation predictions, providing experimental evidence for point defect mediated plastic flow under ion bombardment. For amorphous SiO2, stress relaxation through thermal spikes further contribute to the creep response, resulting in higher fluidities up to ≈ 83 dpa-1GPa -1. Finally, this dissertation presents the further development of the creep testing apparatus for high temperature measurements. The apparatus demonstrated good thermal and mechanical stability and measured irradiation induced creep of nanocrystalline Cu at 200°C. Resulting irradiation induced fluidity is ≈ 10% of the fluidity of the amorphous metals, in agreement with previous measurements on free-standing films. Understanding the creep behavior of nanostructured metals under heavy ion bombardment at elevated temperatures is important for identifying the governing creep mechanisms in these materials. The developed apparatus provides a new and effective method of accelerated mechanical characterization of such promising materials for their potential use in future nuclear applications.

Manipulating and probing angular momentum and quantized circulation in optical fields and matter waves

NASA Astrophysics Data System (ADS)

Lowney, Joseph Daniel

Methods to generate, manipulate, and measure optical and atomic fields with global or local angular momentum have a wide range of applications in both fundamental physics research and technology development. In optics, the engineering of angular momentum states of light can aid studies of orbital angular momentum (OAM) exchange between light and matter. The engineering of optical angular momentum states can also be used to increase the bandwidth of optical communications or serve as a means to distribute quantum keys, for example. Similar capabilities in Bose-Einstein condensates are being investigated to improve our understanding of superfluid dynamics, superconductivity, and turbulence, the last of which is widely considered to be one of most ubiquitous yet poorly understood subjects in physics. The first part of this two-part dissertation presents an analysis of techniques for measuring and manipulating quantized vortices in BECs. The second part of this dissertation presents theoretical and numerical analyses of new methods to engineer the OAM spectra of optical beams. The superfluid dynamics of a BEC are often well described by a nonlinear Schrodinger equation. The nonlinearity arises from interatomic scattering and enables BECs to support quantized vortices, which have quantized circulation and are fundamental structural elements of quantum turbulence. With the experimental tools to dynamically manipulate and measure quantized vortices, BECs are proving to be a useful medium for testing the theoretical predictions of quantum turbulence. In this dissertation we analyze a method for making minimally destructive in situ observations of quantized vortices in a BEC. Secondly, we numerically study a mechanism to imprint vortex dipoles in a BEC. With these advancements, more robust experiments of vortex dynamics and quantum turbulence will be within reach. A more complete understanding of quantum turbulence will enable principles of microscopic fluid flow to be related to the statistical properties of turbulence in a superfluid. In the second part of this dissertation we explore frequency mixing, a subset of nonlinear optical processes in which one or more input optical beam(s) are converted into one or more output beams with different optical frequencies. The ability of parametric nonlinear processes such as second harmonic generation or parametric amplification to manipulate the OAM spectra of optical beams is an active area of research. In a theoretical and numerical investigation, two complimentary methods for sculpting the OAM spectra are developed. The first method employs second harmonic generation with two non-collinear input beams to develop a broad spectrum of OAM states in an optical field. The second method utilizes parametric amplification with collinear input beams to develop an OAM-dependent gain or attenuation, termed dichroism for OAM, to effectively narrow the OAM spectrum of an optical beam. The theoretical principles developed in this dissertation enhance our understanding of how nonlinear processes can be used to engineer the OAM spectra of optical beams and could serve as methods to increase the bandwidth of an optical signal by multiplexing over a range of OAM states.

A modular optical sensor

NASA Astrophysics Data System (ADS)

Conklin, John Albert

This dissertation presents the design of a modular, fiber-optic sensor and the results obtained from testing the modular sensor. The modular fiber-optic sensor is constructed in such manner that the sensor diaphragm can be replaced with different configurations to detect numerous physical phenomena. Additionally, different fiber-optic detection systems can be attached to the sensor. Initially, the modular sensor was developed to be used by university of students to investigate realistic optical sensors and detection systems to prepare for advance studies of micro-optical mechanical systems (MOMS). The design accomplishes this by doing two things. First, the design significantly lowers the costs associated with studying optical sensors by modularizing the sensor design. Second, the sensor broadens the number of physical phenomena that students can apply optical sensing techniques to in a fiber optics sensor course. The dissertation is divided into seven chapters covering the historical development of fiber-optic sensors, a theoretical overview of fiber-optic sensors, the design, fabrication, and the testing of the modular sensor developed in the course of this work. Chapter 1 discusses, in detail, how this dissertation is organized and states the purpose of the dissertation. Chapter 2 presents an historical overview of the development of optical fibers, optical pressure sensors, and fibers, optical pressure sensors, and optical microphones. Chapter 3 reviews the theory of multi-fiber optic detection systems, optical microphones, and pressure sensors. Chapter 4 presents the design details of the modular, optical sensor. Chapter 5 delves into how the modular sensor is fabricated and how the detection systems are constructed. Chapter 6 presents the data collected from the microphone and pressure sensor configurations of the modular sensor. Finally, Chapter 7 discusses the data collected and draws conclusions about the design based on the data collected. Chapter 7 also presents future work needed to expand the functionality and utility of the modular sensor.

Two-Dimensional Spatial Imaging of Charge Transport in Germanium Crystals at Cryogenic Temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moffatt, Robert

2016-03-01

In this dissertation, I describe a novel apparatus for studying the transport of charge in semiconductors at cryogenic temperatures. The motivation to conduct this experiment originated from an asymmetry observed between the behavior of electrons and holes in the germanium detector crystals used by the Cryogenic Dark Matter Search (CDMS). This asymmetry is a consequence of the anisotropic propagation of electrons in germanium at cryogenic temperatures. To better model our detectors, we incorporated this effect into our Monte Carlo simulations of charge transport. The purpose of the experiment described in this dissertation is to test those models in detail. Ourmore » measurements have allowed us to discover a shortcoming in our most recent Monte Carlo simulations of electrons in germanium. This discovery would not have been possible without the measurement of the full, two-dimensional charge distribution, which our experimental apparatus has allowed for the first time at cryogenic temperatures.« less

Issues in Estimating Program Effects and Studying Implementation in Large-Scale Educational Experiments: The Case of a Connected Classroom Technology Program

ERIC Educational Resources Information Center

Shin, Hye Sook

2009-01-01

Using data from a nationwide, large-scale experimental study of the effects of a connected classroom technology on student learning in algebra (Owens et al., 2004), this dissertation focuses on challenges that can arise in estimating treatment effects in educational field experiments when samples are highly heterogeneous in terms of various…

Efficient GPS Position Determination Algorithms

DTIC Science & Technology

2007-06-01

provides two types of services. The Standard Positioning Service (SPS) is designated for the civilian users. The Precise Positioning Service (PPS) is...meters RMS. Military receivers utilized de -encryption techniques to remove SA and provide position accuracy of 10-meters root-mean-square (RMS) [1...difficulties. This type of scenario can be expected in test range applications ([20] and [21]). In this dissertation, the experimental test environment

Polariton effects in naphthalene crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinette, Susan Louise

1977-10-01

The experimental verification of the two-step nature of energy dissipation of photon energy by a crystal is the subject of this dissertation. The ..cap alpha..(O,O) Davydov component of the lowest energy singlet transition in pure strain-free napthalene single crystals is shown to exhibit an increase in absorption with increasing temperature, due to an increase in polariton damping via polariton-phonon scattering processes. (GHT)

The Theory of Love Concept as an Integral Part in the Education of the Educable Mentally Retarded Youth.

ERIC Educational Resources Information Center

Tillman, Lois J.

Examined in the doctoral dissertation research was the effectiveness of a humane value activity oriented summer program to increase IQ scores and improve behaviors of 40 educable mentally retarded (EMR) children between 6 and 12 years of age. Teachers of the experimental group participated in a 10-day workshop on ways to incorporate the humane…

Examining Attitudes, Enjoyment, Flow, and Physical Activity Levels in Pre-Service Teachers Utilizing the BLISS Model Compared to Traditional Dance Instruction

ERIC Educational Resources Information Center

Davis, Christa Ann

2013-01-01

This dissertation describes two studies, based on data collection within a pre-existing collegiate course for pre-service teachers in a children's dance setting at a northwest public university. The overall purpose of these experimental studies was to compare traditional movement/dance with the influence of a relevance-based instructional model,…

Bridging Quantum, Classical and Stochastic Shortcuts to Adiabaticity

NASA Astrophysics Data System (ADS)

Patra, Ayoti

Adiabatic invariants - quantities that are preserved under the slow driving of a system's external parameters - are important in classical mechanics, quantum mechanics and thermodynamics. Adiabatic processes allow a system to be guided to evolve to a desired final state. However, the slow driving of a quantum system makes it vulnerable to environmental decoherence, and for both quantum and classical systems, it is often desirable and time-efficient to speed up a process. Shortcuts to adiabaticity are strategies for preserving adiabatic invariants under rapid driving, typically by means of an auxiliary field that suppresses excitations, otherwise generated during rapid driving. Several theoretical approaches have been developed to construct such shortcuts. In this dissertation we focus on two different approaches, namely counterdiabatic driving and fast-forward driving, which were originally developed for quantum systems. The counterdiabatic approach introduced independently by Dermirplak and Rice [J. Phys. Chem. A, 107:9937, 2003], and Berry [J. Phys. A: Math. Theor., 42:365303, 2009] formally provides an exact expression for the auxiliary Hamiltonian, which however is abstract and difficult to translate into an experimentally implementable form. By contrast, the fast-forward approach developed by Masuda and Nakamura [Proc. R. Soc. A, 466(2116):1135, 2010] provides an auxiliary potential that may be experimentally implementable but generally applies only to ground states. The central theme of this dissertation is that classical shortcuts to adiabaticity can provide useful physical insights and lead to experimentally implementable shortcuts for analogous quantum systems. We start by studying a model system of a tilted piston to provide a proof of principle that quantum shortcuts can successfully be constructed from their classical counterparts. In the remainder of the dissertation, we develop a general approach based on flow-fields which produces simple expressions for auxiliary terms required for both counterdiabatic and fast-forward driving. We demonstrate the applicability of this approach for classical, quantum as well as stochastic systems. We establish strong connections between counterdiabatic and fast-forward approaches, and also between shortcut protocols required for classical, quantum and stochastic systems. In particular, we show how the fast-forward approach can be extended to highly excited states of quantum systems.

A micromechanical study of the damage mechanics of acrylic particulate composites under thermomechanical loading

NASA Astrophysics Data System (ADS)

Nie, Shihua

The main aim of this dissertation was to characterize the damage mechanism and fatigue behavior of the acrylic particulate composite. This dissertation also investigated how the failure mechanism is influenced by changes in certain parameters including the volume fraction of particle, the interfacial bonding strength, the stiffness and thickness of the interphase, and the CTE mismatch between the particle and the matrix. Monotonic uniaxial tensile and compressive testing under various temperatures and strain rates, isothermal low-cycle mechanical testing and thermal cycling of a plate with a cutout were performed. The influence of the interfacial bonding strength between the particle and the matrix on the failure mechanism of the ATH filled PMMA was investigated using in situ observations under uniaxial loading conditions. For composites with weak interfacial bonding, the debonding is the major damage mode. For composites with strong interfacial bonding, the breakage of the agglomerate of particles is the major damage mode. Experimental studies also demonstrated the significant influence of interfacial bonding strength on the fatigue life of the ATH filled PMMA. The damage was characterized in terms of the elastic modulus degradation, the load-drop parameter, the plastic strain range and the hysteresis dissipation. Identifying the internal state variables that quantify material degradation under thermomechanical loading is an active research field. In this dissertation, the entropy production, which is a measure of the irreversibility of the thermodynamic system, is used as the metric for damage. The close correlation between the damage measured in terms of elastic modulus degradation and that obtained from the finite element simulation results validates the entropy based damage evolution function. A micromechanical model for acrylic particulate composites with imperfect interfacial bonds was proposed. Acrylic particulate composites are treated as three-phase composites consisting of agglomerated particles, bulk matrix and an interfacial transition zone around the agglomerate. The influence of the interfacial bonding and the CTE mismatch between the matrix and the filler on the overall thermomechanical behavior of composites is studied analytically and experimentally. The comparison of analytical simulation with experimental data demonstrated the validity of the proposed micromechanical model for acrylic particulate composites with an imperfect interface. (Abstract shortened by UMI.)

Graphite from the University of Idaho Thermolyzed Asphalt Reaction (GUITAR): Fundamental Electrochemical Characterizations

NASA Astrophysics Data System (ADS)

Gyan, Isaiah Owusu

This dissertation details electrochemical characterization of GUITAR (Graphite from the University of Idaho Thermolyzed Asphalt Reaction), a new allotrope of carbon. Applications based on fundamental electrochemical properties of this material are also presented. The dissertation is presented in five chapters. Chapter one presents a summary of the discovery and physical characterizations of GUITAR and how its physical properties position it among carbon materials. In chapter two, fundamental electrochemical properties covering aqueous potential window and electron transfer kinetics with common dissolved redox couples are presented. This chapter highlights significant electrochemical differences between GUITAR and other sp2 carbon materials, notably, fast electron transfer across basal plane GUITAR, contrary to reports at basal planes of graphite and graphene electrodes. In chapter three, the concept of electron transfer facility is extended with biologically relevant molecules. GUITAR is shown to be suitable for biosensing with properties such as; facile electron transfer, low detection limit, high resistance to fouling and stability to anodic regeneration procedures. Chapter four presents further exploration of GUITAR's wide cathodic potential limits in other aqueous electrolytes and preliminary studies towards the exploitation of this property in the negative half of vanadium redox flow battery, where GUITAR-based electrodes are expected to increase coulombic efficiency and increase battery performance due to low hydrogen evolution. Chapter five concludes this dissertation with point-by-point presentation of significant discoveries that highlights GUITAR's uniqueness. This chapter also describes how the various fundamental electrochemical properties of GUITAR make it useful for various applications.

System Design for Nano-Network Communications

NASA Astrophysics Data System (ADS)

ShahMohammadian, Hoda

The potential applications of nanotechnology in a wide range of areas necessities nano-networking research. Nano-networking is a new type of networking which has emerged by applying nanotechnology to communication theory. Therefore, this dissertation presents a framework for physical layer communications in a nano-network and addresses some of the pressing unsolved challenges in designing a molecular communication system. The contribution of this dissertation is proposing well-justified models for signal propagation, noise sources, optimum receiver design and synchronization in molecular communication channels. The design of any communication system is primarily based on the signal propagation channel and noise models. Using the Brownian motion and advection molecular statistics, separate signal propagation and noise models are presented for diffusion-based and flow-based molecular communication channels. It is shown that the corrupting noise of molecular channels is uncorrelated and non-stationary with a signal dependent magnitude. The next key component of any communication system is the reception and detection process. This dissertation provides a detailed analysis of the effect of the ligand-receptor binding mechanism on the received signal, and develops the first optimal receiver design for molecular communications. The bit error rate performance of the proposed receiver is evaluated and the impact of medium motion on the receiver performance is investigated. Another important feature of any communication system is synchronization. In this dissertation, the first blind synchronization algorithm is presented for the molecular communication channels. The proposed algorithm uses a non-decision directed maximum likelihood criterion for estimating the channel delay. The Cramer-Rao lower bound is also derived and the performance of the proposed synchronization algorithm is evaluated by investigating its mean square error.

Integrated electronics and fluidic MEMS for bioengineering

NASA Astrophysics Data System (ADS)

Fok, Ho Him Raymond

Microelectromechanical systems (MEMS) and microelectronics have become enabling technologies for many research areas. This dissertation presents the use of fluidic MEMS and microelectronics for bioengineering applications. In particular, the versatility of MEMS and microelectronics is highlighted by the presentation of two different applications, one for in-vitro study of nano-scale dynamics during cell division and one for in-vivo monitoring of biological activities at the cellular level. The first application of an integrated system discussed in this dissertation is to utilize fluidic MEMS for studying dynamics in the mitotic spindle, which could lead to better chemotherapeutic treatments for cancer patients. Previous work has developed the use of electrokinetic phenomena on the surface of a glass-based platform to assemble microtubules, the building blocks of mitotic spindles. Nevertheless, there are two important limitations of this type of platform. First, an unconventional microfabrication process is necessary for the glass-based platform, which limits the utility of this platform. In order to overcome this limitation, in this dissertation a convenient microfluidic system is fabricated using a negative photoresist called SU-8. The fabrication process for the SU-8-based system is compatible with other fabrication techniques used in developing microelectronics, and this compatibility is essential for integrating electronics for studying dynamics in the mitotic spindle. The second limitation of the previously-developed glass-based platform is its lack of bio-compatibility. For example, microtubules strongly interact with the surface of the glass-based platform, thereby hindering the study of dynamics in the mitotic spindle. This dissertation presents a novel approach for assembling microtubules away from the surface of the platform, and a fabrication process is developed to assemble microtubules between two self-aligned thin film electrodes on thick SU-8 pedestals. This approach also allows the in-vitro model to mimic the three-dimensionality of the cellular mitotic spindle that is absent in previous work. The second application of an integrated bioengineering system discussed in this dissertation is to design and fabricate active electronics and sensors for an in-vivo application to monitor neural activity at the cellular level. Temperature sensors were chosen for a first demonstration. In order for temperature sensors to be able to be implanted into brain interfaces, it is necessary for these devices to be fabricated using processes that are compatible with bio-compatible substrates such as glass and plastic. This dissertation addresses this challenge by developing temperature sensors integrated with biasing circuitry using zinc oxide thin film transistors (TFTs) fabricated on polyimide substrates. The integrated sensors show good temperature sensitivity, which is critical for monitoring neural temperature at the cellular level. This dissertation also describes the unique requirements of encapsulating implantable electronics. For instance, encapsulation schemes must be designed in such a way that they both protect electronic devices from extracellular fluids and also do not interfere with the functionality of these devices. In this work, SU-8 is used as a convenient and effective encapsulation layer. Thermal engineering to prevent active electronics from overheating and to ensure accurate temperature measurement from temperature sensors is also discussed, and a synergistic encapsulation and thermal engineering combination is presented.

Dissertation Leadership Knowledge Transfer Using Sparsely Connected Networks with Bidirectional Edges: Case Study of Chester Hayden McCall Jr., His Dissertation Advisors, and His Students

ERIC Educational Resources Information Center

Mallette, Leo A.

2012-01-01

There are many modes of information flow in the sciences: books, journals, conferences, research and development, acquisition of companies, co-workers, students, and professors in schools of higher learning. In the sciences, dissertation students learn from their dissertation advisor (or chairperson or mentor) and the other dissertation committee…

Innovative options for the doctoral dissertation in nursing.

PubMed

Robinson, Susan; Dracup, Kathleen

2008-01-01

The doctoral dissertation is the capstone event of doctoral study. While developing their dissertations, graduate students discover the cutting edge of the discipline, learn the intricacies of the research process, and engage in scientific dialogue with experts in the field. Traditional dissertation formats are confined to the Dissertation Abstracts International and are not easily accessed by clinicians, administrators, and researchers who are most in need of the information. Consequently, the number of universities offering options to the traditional dissertation format is growing. This article describes and compares 2 formats: the traditional dissertation and the publication option. The benefits and challenges of each format to doctoral students and faculty are discussed. The discussion reflects changing trends in the nursing profession as an academic discipline.

Vision in Sight: The Relationships between Knowledge, Health Beliefs and Treatment Outcomes. The Case of Amblyopia. Linkoping Studies in Education and Psychology, Dissertation No. 65.

ERIC Educational Resources Information Center

Goransson, Anne

The research reported is an experimental study on the effects of intensified education of Swedish parents of children with amblyopia (dimness of sight without apparent organic defect) on their understanding of the nature of the disease, its origins, and treatment. Parents in the control group (n=60) were exposed to the ordinary information…

Recherches Sur La Psychologie de L'enfant de Milieu Defavorise. Rapport- synthese. (Research Relating to the Psychology of the Child in Disadvantaged Environments. Summary Report).

ERIC Educational Resources Information Center

Caouette, Charles E.; Bourbeau, Gerald

Thirteen doctoral dissertations and five masters theses are summarized in this report of research on the disadvantaged child. Contained in each individual summary are the detailed descriptions of the experimental task, the results obtained and the analysis of these results. The eighteen individual theses are concerned with topics such as:…

Optical properties of fly ash. Volume 1, Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Self, S.A.

1994-12-01

Research performed under this contract was divided into four tasks under the following headings: Task 1, Characterization of fly ash; Task 2, Measurements of the optical constants of slags; Task 3, Calculations of the radiant properties of fly ash dispersions; and Task 4, Measurements of the radiant properties of fly ash dispersions. Tasks 1 and 4 constituted the Ph.D. research topic of Sarbajit Ghosal, while Tasks 2 and 3 constituted the Ph.D. research topic of Jon Ebert. Together their doctoral dissertations give a complete account of the work performed. This final report, issued in two volumes consists of an executivemore » summary of the whole program followed by the dissertation of Ghosal. Volume 1 contains the dissertation of Ghosal which covers the characterization of fly ash and the measurements of the radiant properties of fly ash dispersions. A list of publications and conference presentations resulting from the work is also included.« less

High Efficiency Electron-Laser Interactions in Tapered Helical Undulators

NASA Astrophysics Data System (ADS)

Duris, Joseph Patrick

Efficient coupling of relativistic electron beams with high power radiation lies at the heart of advanced accelerator and light source research and development. The inverse free electron laser is a stable accelerator capable of harnessing very high intensity laser electric fields to efficiently transfer large powers from lasers to electron beams. In this dissertation, we first present the theoretical framework to describe the interaction, and then apply our improved understanding of the IFEL to the design and numerical study of meter-long, GeV IFELs for compact light sources. The central experimental work of the dissertation is the UCLA BNL helical inverse free electron laser experiment at the Accelerator Test Facility in Brookhaven National Laboratory which used a strongly tapered 54cm long, helical, permanent magnet undulator and a several hundred GW CO2 laser to accelerate electrons from 52 to 106MeV, setting new records for inverse free electron laser energy gain (54MeV) and average accelerating gradient (100MeV/m). The undulator design and fabrication as well as experimental diagnostics are presented. In order to improve the stability and quality of the accelerated electron beam, we redesigned the undulator for a slightly reduced output energy by modifying the magnet gap throughout the undulator, and we used this modified undulator to demonstrated capture of >25% of the injected beam without prebunching. In the study of heavily loaded GeV inverse free electron lasers, we show that a majority of the power may be transferred from a laser to the accelerated electron beam. Reversing the process to decelerate high power electron beams, a mechanism we refer to as tapering enhanced stimulated superradiant amplification, offers a clear path to high power light sources. We present studies of radiation production for a wide range of wavelengths (10mum, 13nm, and 0.3nm) using this method and discuss the design for a deceleration experiment using the same undulator used for acceleration in this experiment. By accounting for the evolving radiation field in the design of the undulator tapering, a large fraction of energy may be transferred between the electrons and laser, enabling compact, high-current GeV accelerators and various wavelength light-sources of unprecedented peak powers.

Signal processing for passive detection and classification of underwater acoustic signals

NASA Astrophysics Data System (ADS)

Chung, Kil Woo

2011-12-01

This dissertation examines signal processing for passive detection, classification and tracking of underwater acoustic signals for improving port security and the security of coastal and offshore operations. First, we consider the problem of passive acoustic detection of a diver in a shallow water environment. A frequency-domain multi-band matched-filter approach to swimmer detection is presented. The idea is to break the frequency contents of the hydrophone signals into multiple narrow frequency bands, followed by time averaged (about half of a second) energy calculation over each band. Then, spectra composed of such energy samples over the chosen frequency bands are correlated to form a decision variable. The frequency bands with highest Signal/Noise ratio are used for detection. The performance of the proposed approach is demonstrated for experimental data collected for a diver in the Hudson River. We also propose a new referenceless frequency-domain multi-band detector which, unlike other reference-based detectors, does not require a diver specific signature. Instead, our detector matches to a general feature of the diver spectrum in the high frequency range: the spectrum is roughly periodic in time and approximately flat when the diver exhales. The performance of the proposed approach is demonstrated by using experimental data collected from the Hudson River. Moreover, we present detection, classification and tracking of small vessel signals. Hydroacoustic sensors can be applied for the detection of noise generated by vessels, and this noise can be used for vessel detection, classification and tracking. This dissertation presents recent improvements aimed at the measurement and separation of ship DEMON (Detection of Envelope Modulation on Noise) acoustic signatures in busy harbor conditions. Ship signature measurements were conducted in the Hudson River and NY Harbor. The DEMON spectra demonstrated much better temporal stability compared with the full ship spectra and were measured at distances up to 7 km. The combination of cross-correlation and DEMON methods allows separation of the acoustic signatures of ships in busy urban environments. Finally, we consider the extension of this algorithm for vessel tracking using phase measurement of the DEMON signal recorded by two or more hydrophones. Tests conducted in the Hudson River and NY Bay confirmed opportunity of Direction of Arrival (DOA) funding using the phase DEMON method.

Physical properties of organic and biomaterials: Fundamentals and applications

NASA Astrophysics Data System (ADS)

Steven, Eden

Silk materials are natural protein-based materials with an exceptional toughness. In addition to their toughness, silk materials also possess complex physical properties and functions resulting from a particular set of amino-acid arrangement that produces structures with crystalline beta-sheets connected by amorphous chains. Extensive studies have been performed to study their structure-function relationship leading to recent advancements in bio-integrated devices. Applications to fields other than textiles and biomedicine, however, have been scarce. In this dissertation, an investigation of the electronic properties, functionalization, and role of silk materials (spider silk and Bombyx mori cocoon silk) in the field of organic materials research is presented. The investigation is conducted from an experimental physics point of view where correlations with charge transport mechanisms in disordered, semiconducting, and insulating materials are made when appropriate. First, I present the electronic properties of spider silk fibers under ambient, humidified, iodized, polar solvent exposure, and pyrolized conditions. The conductivity is exponentially dependent on relative humidity changes and the solvent polarity. Iodine doping increases the conductivity only slightly but has pronounced effects on the pyrolization process, increasing the yield and flexibility of the pyrolized silk fibers. The iodized samples were further studied using magic angle spinning nuclear magnetic resonance (MAS-NMR) and Fourier transform infrared spectroscopy (FTIR) revealing non-homogenous iodine doping and I2 induced hydrogenation that are responsible for the minimal conductivity improvement and the pyrolization effects, respectively. Next, I present the investigation of silk fiber functionalization with gold and its role in electrical measurements. The gold functionalized silk fiber (Au-SS) is metallic down to cryogenic temperatures, has a certain amount of flexibility, and possesses magnetic field independent conductivity at low temperatures. This allows their use as micro-wires and flexible electrodes for transport measurements of small organic samples. I also found that neat spider silk fiber can be used as the mask for lithographic processes, providing a simple route of fabricating adhesive stamp electrodes for measuring transport properties of supra-micron samples in the lateral range of 15 mum--100 mum and thickness > 1 mum at low temperatures and high magnetic fields. The current-voltage characteristic of the insulating channel in tape adhesive electrodes revealed Fowler-Nordheim tunneling mechanism. For electronic sensing and actuating device applications, I have developed a simple method for silk functionalization with carbon nanotubes (CNT) facilitated by polar attraction and supercontraction, a phenomenon where silk is softened when exposed to water. Uniform CNT coating and CNT penetration into the silk fiber surface are evident from the SEM and cross-sectional TEM studies. The conductivity of the carbon nanotube functionalized silk fiber (CNT-SS) follows variable range hopping behavior with activation energy similar to that observed in buckpaper. In addition to being electrically conducting, the CNT-SS is custom-shapeable, flexible, and sensitive to humidity, allowing its use as a heart-pulse and humidity resistive sensors, as well as for current-driven actuators. Finally, I present the investigation of the processed Bombyx mori silk thin film. The silk thin film exhibits actuating and self-healing properties similar to those of a biological muscle. Proof-of-concept silk-based bio-mimetic muscle and water-based memory device are demonstrated. The silk thin film is also used as the dielectric layer of a diF-TESADT organic field effect transistor (FET) where I observed a lower operating voltage and an enhancement in the mobility of the device compared with the FET using SiO 2 dielectric layer, accompanied with an anomalous source-drain current-voltage characteristics. This dissertation aims to demonstrate the different aspects of exercising experimental physics to an inter-disciplinary research subject. The fundamental characterization and instrumentation developed in this work are intended to stimulate future discoveries by providing new experimental tools to study electronic transport properties of new materials. In addition, the device fabrication principles will be valuable for development of more environmental-friendly electronics. The treatment presented in this dissertation should serve as a roadmap for future studies of natural materials from an experimental physics point of view.

[HYGIENE: STRUCTURE OF INNOVATIVE RESEARCH STUDIES IN RUSSIA (2000-2014)].

PubMed

Evdokimov, V I; Popov, V I; Rut, A N

2015-01-01

There was analyzed the array of 1548 dissertations on the scientific specialty 14.02.01 (former specification 14.00.07) "Hygiene". Over period of 2000-2014 to the Dissertation Committee in Russia there were annually submitted (103 ± 10) theses, which include (21 ± 3) doctoral dissertations and (83 ± 8) candidate dissertations. Doctoral dissertations accounted for 20,1%, dissertations in medicine--89.3%. There was established not only the decline in the number of theses in hygiene, but the reduction of their proportion in the total array of all medical and biological dissertations in Russia. The conjugacy of the trend curves of the total stream of dissertations in medicine and biology in Russia and in hygiene is considered to be not very high (r = 0.54). In the total structure of dissertation works on General Hygiene accounted for 22.7%, Community Hygiene--15.45%, Occupational Hygiene--19.6%, Children's and Adolescents' Hygiene--24.7%, Nutrition Hygiene--8.2%, Radiation Hygiene--2.3%, in Rural Hygiene--1.2%, Hospital Hygiene-- 3.4%, Military Hygiene--2.3% correspondingly. There is pointed the development gap between the research studies in hygiene and tendency in training of high class health care professionals' in Russia.

Successful Beam-Beam Tuneshift Compensation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishofberger, Kip Aaron

2005-01-01

The performance of synchrotron colliders has been limited by the beam-beam limit, a maximum tuneshift that colliding bunches could sustain. Due to bunch-to-bunch tune variation and intra-bunch tune spread, larger tuneshifts produce severe emittance growth. Breaking through this constraint has been viewed as impossible for several decades. This dissertation introduces the physics of ultra-relativistic synchrotrons and low-energy electron beams, with emphasis placed on the limits of the Tevatron and the needs of a tuneshift-compensation device. A detailed analysis of the Tevatron Electron Lens (T EL) is given, comparing theoretical models to experimental data whenever possible. Finally, results of Tevatron operationsmore » with inclusion of the T EL are presented and analyzed. It is shown that the T EL provides a way to shatter the previously inescapable beam-beam limit.« less

Effect of Metallic Li on the Behavior of Metals in Molten Salts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chidambaram, Dev; Phillips, William; Merwin, Augustus

The deleterious effect of Li0 on the reactor container materials has not been studied. Exposure to liquid Li 0 results in material degradation primarily through lithium intercalation, leaching of specific alloying elements, and decarburization. The objective of this research is to understand how the presence of Li 0 in molten LiCl-Li 2O affects the degradation of two classes of alloys by correlating their accelerated and long term electrochemical behavior to the surface chemistry of the alloys and the chemistry of the electrolyte. This study has completed all the proposed tasks. The project led to the design and development of uniquemore » experimental setups and protocols. Several groundbreaking findings resulted from this study. The project had several products in terms of student education, thesis and dissertation, publications and presentations.« less

The Conceptual Dissertation: Commentaries by Practitioners as Inquirers.

ERIC Educational Resources Information Center

Garman, Noreen B.; And Others

Opinions about the conceptual dissertation are offered in seven colloquium papers by educational practitioners/scholars who have finished their dissertations over the past 5 years. Conceptual/interpretive dissertation research issues include finding a consistent language and research rationale for studies. In addition to an introduction by Noreen…

Passive auto-focus for digital still cameras and camera phones: Filter-switching and low-light techniques

NASA Astrophysics Data System (ADS)

Gamadia, Mark Noel

In order to gain valuable market share in the growing consumer digital still camera and camera phone market, camera manufacturers have to continually add and improve existing features to their latest product offerings. Auto-focus (AF) is one such feature, whose aim is to enable consumers to quickly take sharply focused pictures with little or no manual intervention in adjusting the camera's focus lens. While AF has been a standard feature in digital still and cell-phone cameras, consumers often complain about their cameras' slow AF performance, which may lead to missed photographic opportunities, rendering valuable moments and events with undesired out-of-focus pictures. This dissertation addresses this critical issue to advance the state-of-the-art in the digital band-pass filter, passive AF method. This method is widely used to realize AF in the camera industry, where a focus actuator is adjusted via a search algorithm to locate the in-focus position by maximizing a sharpness measure extracted from a particular frequency band of the incoming image of the scene. There are no known systematic methods for automatically deriving the parameters such as the digital pass-bands or the search step-size increments used in existing passive AF schemes. Conventional methods require time consuming experimentation and tuning in order to arrive at a set of parameters which balance AF performance in terms of speed and accuracy ultimately causing a delay in product time-to-market. This dissertation presents a new framework for determining an optimal set of passive AF parameters, named Filter- Switching AF, providing an automatic approach to achieve superior AF performance, both in good and low lighting conditions based on the following performance measures (metrics): speed (total number of iterations), accuracy (offset from truth), power consumption (total distance moved), and user experience (in-focus position overrun). Performance results using three different prototype cameras are presented to further illustrate the real-world AF performance gains achieved by the developed approach. The major contribution of this dissertation is that the developed auto focusing approach can be successfully used by camera manufacturers in the development of the AF feature in future generations of digital still cameras and camera phones.

Differences in mathematics and science performance by economic status, gender, and ethnicity/race: A multiyear Texas statewide study

NASA Astrophysics Data System (ADS)

Anderson, Pamela Bennett

Purpose. The purpose of the first study was to ascertain the extent to which differences were present in the STAAR Mathematics and Science test scores by Grade 5 and Grade 8 student economic status. The purpose of the second study was to examine differences in Grade 5 STAAR Mathematics and Science test performance by gender and by ethnicity/race (i.e., Asian, Black, Hispanic, and White). Finally, with respect to the third study in this journal-ready dissertation, the purpose was to investigate the STAAR Mathematics and Science test scores of Grade 8 students by gender and by ethnicity/race (i.e., Asian, Black, Hispanic, and White). Method. For this journal-ready dissertation, a non-experimental, causal-comparative research design (Creswell, 2009) was used in all three studies. Grade 5 and Grade 8 STAAR Mathematics and Science test data were analyzed for the 2011-2012 through the 2014-2015 school years. The dependent variables were the STAAR Mathematics and Science test scores for Grade 5 and Grade 8. The independent variables analyzed in these studies were student economic status, gender, and ethnicity/race. Findings. Regarding the first study, statistically significant differences were present in Grade 5 and Grade 8 STAAR Mathematics and Science test scores by student economic status for each year. Moderate effect sizes (Cohen's d) were present for each year of the study for the Grade 5 STAAR Mathematics and Science exams, Grade 8 Science exams, and the 2014-2015 Grade 8 STAAR Mathematics exam. However, a small effect size was present for the 2011-2012 through 2013-2014 Grade 8 STAAR Mathematics exam. Regarding the second and third study, statistically significant differences were revealed for Grade 5 and Grade 8 STAAR Mathematics and Science test scores based on gender, with trivial effect sizes. Furthermore, statistically significant differences were present in these test scores by ethnicity/race, with moderate effects for each year of the study. With regard to each year for both studies, Asian students had the highest average test scores, followed by White, Hispanic, and Black students, respectively. Thus, a stairstep achievement gap (Carpenter, Ramirez, & Severn, 2006) was present.

Interferometry-based free space communication and information processing

NASA Astrophysics Data System (ADS)

Arain, Muzammil Arshad

This dissertation studies, analyzes, and experimentally demonstrates the innovative use of interference phenomenon in the field of opto-electronic information processing and optical communications. A number of optical systems using interferometric techniques both in the optical and the electronic domains has been demonstrated in the filed of signal transmission and processing, optical metrology, defense, and physical sensors. Specifically it has been shown that the interference of waves in the form of holography can be exploited to realize a novel optical scanner called Code Multiplexed Optical Scanner (C-MOS). The C-MOS features large aperture, wide scan angles, 3-D beam control, no moving parts, and high beam scanning resolution. A C-MOS based free space optical transceiver for bi-directional communication has also been experimentally demonstrated. For high speed, large bandwidth, and high frequency operation, an optically implemented reconfigurable RF transversal filter design is presented that implements wide range of filtering algorithms. A number of techniques using heterodyne interferometry via acousto-optic device for optical path length measurements have been described. Finally, a whole new class of interferometric sensors for optical metrology and sensing applications is presented. A non-traditional interferometric output signal processing scheme has been developed. Applications include, for example, temperature sensors for harsh environments for a wide temperature range from room temperature to 1000°C.

Dissertation Genre Change as a Result of Electronic Theses and Dissertation Programs

ERIC Educational Resources Information Center

Pantelides, Kate

2015-01-01

The increasing prevalence of mandatory Electronic Theses and Dissertations (ETDs) policies has ushered in rather dramatic dissertation genre change. The affordances of the medium offer expanded access and audience, availability of new compositional tools, and alternate formats, the implications of which are just beginning to appear in…

Good Undergraduate Dissertation Supervision: Perspectives of Supervisors and Dissertation Coordinators

ERIC Educational Resources Information Center

Roberts, Lynne D.; Seaman, Kristen

2018-01-01

There is a paucity of research, training, and material available to support supervisors of undergraduate dissertation students. This article explores what "good" supervision might look like at this level. Interviews were conducted with eight new supervisors and six dissertation coordinators using a critical incident methodology. Thematic…

Graduate Students "Show Their Work": Metalanguage in Dissertation Methodology Sections

ERIC Educational Resources Information Center

Pantelides, Kate L.

2017-01-01

To address graduate writing pedagogy in technical communication, this article reports on a study of 14 award-winning dissertations in the field. By treating dissertations as cultural artifacts constitutive of the educational contexts in which they are authored, this study reads dissertation methodology sections as research narratives to understand…

34 CFR 662.1 - What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Research Abroad Fellowship Program? 662.1 Section 662.1 Education Regulations of the Offices of the... DOCTORAL DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM General § 662.1 What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program? (a) The Fulbright-Hays Doctoral Dissertation...

34 CFR 662.1 - What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Research Abroad Fellowship Program? 662.1 Section 662.1 Education Regulations of the Offices of the... DOCTORAL DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM General § 662.1 What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program? (a) The Fulbright-Hays Doctoral Dissertation...

34 CFR 662.1 - What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Research Abroad Fellowship Program? 662.1 Section 662.1 Education Regulations of the Offices of the... DOCTORAL DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM General § 662.1 What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program? (a) The Fulbright-Hays Doctoral Dissertation...

34 CFR 662.1 - What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Research Abroad Fellowship Program? 662.1 Section 662.1 Education Regulations of the Offices of the... DOCTORAL DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM General § 662.1 What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program? (a) The Fulbright-Hays Doctoral Dissertation...

34 CFR 662.1 - What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Research Abroad Fellowship Program? 662.1 Section 662.1 Education Regulations of the Offices of the... DOCTORAL DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM General § 662.1 What is the Fulbright-Hays Doctoral Dissertation Research Abroad Fellowship Program? (a) The Fulbright-Hays Doctoral Dissertation...

Disseminating a Successful Faculty Dissertation Completion Project.

ERIC Educational Resources Information Center

Sternberg, David

This final report describes a project of the City University of New York's Faculty Advancement Program (FAP) to encourage dissertation completion by ABD (all but dissertation) faculty at seven institutions in four northeastern states. The institutions were visited and revisited by FAP mentors in the effort to establish dissertation completion…

Historical Trends in Counsellor Education Dissertations

ERIC Educational Resources Information Center

Richards, Judith; Dykeman, Cass; Bender, Sara

2016-01-01

There exists a dearth of literature on the content, research method and research design trends of dissertations in education. Within one large subfield of education (i.e. counsellor education), an online and full-text archive of dissertations has become available. This archive contains over 200 dissertations produced in Oregon State University's…

STEM Education Related Dissertation Abstracts: A Bounded Qualitative Meta-Study

ERIC Educational Resources Information Center

Banning, James; Folkestad, James E.

2012-01-01

This article utilizes a bounded qualitative meta-study framework to examine the 101 dissertation abstracts found by searching the ProQuest Dissertation and Theses[TM] digital database for dissertations abstracts from 1990 through 2010 using the search terms education, science, technology, engineer, and STEM/SMET. Professional search librarians…

The Evolution of Surface Symmetry in Femtosecond Laser-Induced Transient States of Matter

NASA Astrophysics Data System (ADS)

Garnett, Joy Carleen

Gallium arsenide and other III-V materials are well known for their excellent optical and electronic properties and have led to the development of high-performance photovoltaic cells1,2, photoelectrochemical water splitting3,4, and light emitting diodes (LEDs)5. Several combinations of III-V semiconductors are now being considered as potentially attractive alternatives to silicon for these applications. However, further development requires fundamental understanding of processes that govern light-matter interactions. Specifically, surface strain and ultrafast dynamics are of great interest to the optoelectronic industry. Strained semiconductor surfaces dominate the design of optoelectronics and III-V semiconductor-based LEDs. Currently, the structures of strained surfaces are well characterized with x-ray diffraction (XRD)6 and electron crystallography7-9. However, optically-induced electronic behavior at these interfaces are not fully understood. This has the been one of the stimulants for the research in this dissertation. To further explore opticallyinduced electronic behavior at strained interfaces, I have asked the following questions: 1. How does static optoelectronic behavior change as a function of strain? 2. How does surface symmetry and electronic motion change with respect to strain? 3. How do atomic bonds change as a function of strain? Another main research goal of this work is to understand ultrafast subpicosecond processes after pulsed laser excitation. The knowledge of ultrafast processes dominates the design of devices in industries that require high temporal and spectral resolution. Ultrafast atomic motion has been the major focus of subpicosecond structural dynamics. Currently, these dynamics upon photoexcitation are well characterized with experimental methods such as ultrafast x-ray diffraction (U-XRD), ultrafast electron diffraction (UED), and ultrafast electron crystallography (UEC). However, ultrafast atomic motion does not occur alone. The bonds connecting these moving atoms are also affected during this process. The correlation between structural and electronic dynamics is not well understood. To further explore correlated structural and electronic behavior upon ultrafast laser excitation, I have asked the following questions: 1. How does subpicosecond optoelectronic behavior change as a function of time after femtosecond pulse photoexcitation? 2. How does subpicosecond surface symmetry and electronic motion change with respect to time after femtosecond pulse photoexcitation? 3. How do atomic bonds change as a function of time after femtosecond pulse photoexcitation? To address these questions, I used experimental methods sensitive to both atomic motions and electronic responses: polarization-resolved second harmonic generation (PRSHG) and timeresolved, polarization-resolved second harmonic generation (TRPRSHG). The dissertation covers application of these techniques to III-V semiconductors: gallium arsenide (GaAs), gallium antimonide (GaSb), and aluminum gallium arsenide (AlGaAs). This dissertation is organized as follows. Chapter 2 presents the background of electronic band structures, ultrafast relaxation processes, and the origin of nonlinear optics from the perspectives of classical and quantum mechanics. It thus provides a framework for the static and transient nonlinear optical processes observed in III-V semiconductors under ultrafast pulse excitation. Next, Chapter 3 motivates the use of the experimental and analytical methods as applied to the experimental and theoretical studies outlined in Chapters 4 and 5. Chapter 4 is devoted to the understanding of polarization-resolved second-order nonlinear optical responses of various strained III-V semiconductor heterostructures resulting from defect-conducive growth conditions. Simplified phenomenological expressions for the polarization-resolved second harmonic generation (PRSHG) are first derived using tensor analysis. Afterwards, these expressions are used to fit experimental data. The developed formalism is tested under different conditions to gauge the fit robustness and sensitivity to mechanical and electronic changes in strained IIIV semiconductors. Along that same vein, Chapter 5 extends this analytical fit to describe ultrafast PRSHG responses of GaAs (100) as a function of transient changes in the interatomic potential within the first picosecond after photoexcitation. Finally, the dissertation concludes with Chapter 6 addressing possible directions for future work. The chapter begins with a description of studies to further test the sensitivity and robustness of the PRSHG phenomenological fit and how it can be used to characterize more classes of materials.

Application of optical spectroscopic techniques for disease diagnosis

NASA Astrophysics Data System (ADS)

Saha, Anushree

Optical spectroscopy, a truly non-invasive tool for remote diagnostics, is capable of providing valuable information on the structure and function of molecules. However, most spectroscopic techniques suffer from drawbacks, which limit their application. As a part of my dissertation work, I have developed theoretical and experimental methods to address the above mentioned issues. I have successfully applied these methods for monitoring the physical, chemical and biochemical parameters of biomolecules involved in some specific life threatening diseases like lead poisoning and age-related macular degeneration (AMD). I presented optical studies of melanosomes, which are one of the vital organelles in the human eye, also known to be responsible for a disease called age-related macular degeneration (AMD), a condition of advanced degeneration which causes progressive blindness. I used Raman spectroscopy, to first chemically identify the composition of melanosome, and then monitor the changes in its functional and chemical behavior due to long term exposure to visible light. The above study, apart from explaining the role of melanosomes in AMD, also sets the threshold power for lasers used in surgeries and other clinical applications. In the second part of my dissertation, a battery of spectroscopic techniques was successfully applied to explore the different binding sites of lead ions with the most abundant carrier protein molecule in our circulatory system, human serum albumin. I applied optical spectroscopic tools for ultrasensitive detection of heavy metal ions in solution which can also be used for lead detection at a very early stage of lead poisoning. Apart from this, I used Raman microspectroscopy to study the chemical alteration occurring inside a prostate cancer cell as a result of a treatment with a low concentrated aqueous extract of a prospective drug, Nerium Oleander. The experimental methods used in this study has tremendous potential for clinical application and will gain widespread acceptance within next few years from bench to bedside as an inexpensive and non-invasive tool compared to the other technologies.

Investigation of metallurgical coatings for automotive applications

NASA Astrophysics Data System (ADS)

Su, Jun Feng

Metallurgical coatings have been widely used in the automotive industry from component machining, engine daily running to body decoration due to their high hardness, wear resistance, corrosion resistance and low friction coefficient. With high demands in energy saving, weight reduction and limiting environmental impact, the use of new materials such as light Aluminum/magnesium alloys with high strength-weight ratio for engine block and advanced high-strength steel (AHSS) with better performance in crash energy management for die stamping, are increasing. However, challenges are emerging when these new materials are applied such as the wear of the relative soft light alloys and machining tools for hard AHSS. The protective metallurgical coatings are the best option to profit from these new materials' advantages without altering largely in mass production equipments, machinery, tools and human labor. In this dissertation, a plasma electrolytic oxidation (PEO) coating processing on aluminum alloys was introduced in engine cylinder bores to resist wear and corrosion. The tribological behavior of the PEO coatings under boundary and starve lubrication conditions was studied experimentally and numerically for the first time. Experimental results of the PEO coating demonstrated prominent wear resistance and low friction, taking into account the extreme working conditions. The numerical elastohydrodynamic lubrication (EHL) and asperity contact based tribological study also showed a promising approach on designing low friction and high wear resistant PEO coatings. Other than the fabrication of the new coatings, a novel coating evaluation methodology, namely, inclined impact sliding tester was presented in the second part of this dissertation. This methodology has been developed and applied in testing and analyzing physical vapor deposition (PVD)/ chemical vapor deposition (CVD)/PEO coatings. Failure mechanisms of these common metallurgical hard coatings were systematically studied and summarized via the new testing methodology. Field tests based on the new coating characterization technique proved that this methodology is reliable, effective and economical.

Iteration in Early-Elementary Engineering Design

NASA Astrophysics Data System (ADS)

McFarland Kendall, Amber Leigh

K-12 standards and curricula are beginning to include engineering design as a key practice within Science Technology Engineering and Mathematics (STEM) education. However, there is little research on how the youngest students engage in engineering design within the elementary classroom. This dissertation focuses on iteration as an essential aspect of engineering design, and because research at the college and professional level suggests iteration improves the designer's understanding of problems and the quality of design solutions. My research presents qualitative case studies of students in kindergarten and third-grade as they engage in classroom engineering design challenges which integrate with traditional curricula standards in mathematics, science, and literature. I discuss my results through the lens of activity theory, emphasizing practices, goals, and mediating resources. Through three chapters, I provide insight into how early-elementary students iterate upon their designs by characterizing the ways in which lesson design impacts testing and revision, by analyzing the plan-driven and experimentation-driven approaches that student groups use when solving engineering design challenges, and by investigating how students attend to constraints within the challenge. I connect these findings to teacher practices and curriculum design in order to suggest methods of promoting iteration within open-ended, classroom-based engineering design challenges. This dissertation contributes to the field of engineering education by providing evidence of productive engineering practices in young students and support for the value of engineering design challenges in developing students' participation and agency in these practices.

[Old medical dissertations in the field of obstetrics and gynaecology at the University Frankfurt-on-Oder (Viadrina), 1700-1811].

PubMed

Rummler, Siegbert

2008-01-01

Based on an analysis of the medical dissertations which have survived from the University of Frankfurt-on-Oder (Viadrina), this paper illustrates the importance of old medical dissertations as historical sources. For 389 out of 570 medical students who received their medical doctorate at the Viadrina between the years 1700 and 1811, the topics of their dissertations have been ascertained. 15 dissertations on obstetrical and gynaecological topics are more closely analysed.

Effects of Low-Altitude Aircraft Overflights on Domestic Turkey Poults

DTIC Science & Technology

1990-06-30

density rearing systems, too much heat, nutritional and mineral deficiencies, and irritation from parasites. If birds pick on one another or scratch...influence of flight noise on mortality and productivity in broiler chickens and in hen behavior," Inaugural Dissertation for Animal Hygiene at the...and were housed in two 2 x 6 m covered chicken wire pens at the experimental site (see Figure 2-4). Originally, they were to have been acclimatized

Coherent Change Detection: Theoretical Description and Experimental Results

DTIC Science & Technology

2006-08-01

373–376. 47. S. M. Kay, Fundamentals of statistic signal processing. Vol 2. Detection theory. Pren- tice Hall, 1998. 48. H . Anton and C . Rorres ...Proceedings of the 1998 International Geoscience and Remote Sensing Symposium, vol. 5, 1998, pp. 2451–2453. 9. C . V. Jakowatz Jr., D. E. Wahl, P. H . Eichel...dissertation, School of Electrical and Electronic Engineering, The University of Adelaide, 2004. 20. C . H . Gierull, Statistics of SAR interferograms

Macro-Focused Social Work Dissertations: A Preliminary Look at the Numbers

ERIC Educational Resources Information Center

Fogel, Sondra J.; Ersing, Robin

2016-01-01

Dissertation research is an important indicator of practice trends and emerging issues. The social work profession relies on this scholarship to build its knowledge base thus reducing reliance on cognate fields. It is worthwhile to note how many dissertations are being completed and to review the categories being pursued in dissertation products…

Geo-Bibliometric Mapping of French Geography: An Examination of Geography Dissertations Produced in France

ERIC Educational Resources Information Center

Herubel, Jean-Pierre V. M.

2005-01-01

French geography dissertations for the years 1985-2002 were examined for their salient characteristics in terms of degree production, dissertation type, institutional affiliation, and geographical reach. These dissertations offer a rich base of research conducted in a country known for its innovative geographical research and tradition. Particular…

7 CFR 3402.6 - Overview of the special international study and/or thesis/dissertation research travel allowance.

Code of Federal Regulations, 2014 CFR

2014-01-01

... thesis/dissertation research travel allowance. 3402.6 Section 3402.6 Agriculture Regulations of the... Overview of the special international study and/or thesis/dissertation research travel allowance. (a) For.../dissertation research travel allowance, the Project Director must apply to HEP for a supplemental grant in...

7 CFR 3402.6 - Overview of the special international study and/or thesis/dissertation research travel allowance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... thesis/dissertation research travel allowance. 3402.6 Section 3402.6 Agriculture Regulations of the... Overview of the special international study and/or thesis/dissertation research travel allowance. (a) For.../dissertation research travel allowance, the Project Director must apply to HEP for a supplemental grant in...

Examining Foundations of Qualitative Research: A Review of Social Work Dissertations, 2008-2010

ERIC Educational Resources Information Center

Gringeri, Christina; Barusch, Amanda; Cambron, Christopher

2013-01-01

This study examined the treatment of epistemology and methodological rigor in qualitative social work dissertations. Template-based review was conducted on a random sample of 75 dissertations completed between 2008 and 2010. For each dissertation, we noted the presence or absence of four markers of epistemology: theory, paradigm, reflexivity, and…

College Housing Dissertations: A Bounded Qualitative Meta-Study

ERIC Educational Resources Information Center

Banning, James H.; Kuk, Linda

2011-01-01

The purpose of this study was to examine dissertations that were published in the U.S. during the past 5 years that related to collegiate housing. The dissertations were examined using a bounded qualitative meta-analysis approach. Each dissertation was examined using three questions: What were the methods/attributes of the research? What were the…

34 CFR 662.20 - How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 34 Education 3 2011-07-01 2011-07-01 false How is a Fulbright-Hays Doctoral Dissertation Research... DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM Selection of Fellows § 662.20 How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected? (a) The Secretary considers applications for fellowships under...

34 CFR 662.20 - How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false How is a Fulbright-Hays Doctoral Dissertation Research... DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM Selection of Fellows § 662.20 How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected? (a) The Secretary considers applications for fellowships under...

Writing a Book from Your Dissertation: Seven Stages

ERIC Educational Resources Information Center

Pane, Debra M.

2016-01-01

The purpose of this Writer's Forum is to share seven stages for writing a book from your dissertation: relinquishing control of your dissertation; selecting and working with your publisher; defining and writing for your audience; revising and drafting your dissertation into a book; securing and using feedback; including front matter, back matter,…

A study of hadronic decays of the chi(c) states produced in psi-prime radiative transitions at the Beijing Experimental Spectrometer

NASA Astrophysics Data System (ADS)

Varner, Gary Sim

1999-11-01

Utilizing the world's largest sample of resonant y' decays, as measured by the Beijing Experimental Spectrometer (BES) during 1993-1995, a comprehensive study of the hadronic decay modes of the χc (3P1 Charmonium) states has been undertaken. Compared with the data set for the Mark I detector, whose published measurements of many of these hadronic decays have been definitive for almost 20 years, roughly an order of magnitude larger statistics has been obtained. Taking advantage of these larger statistics, many new hadronic decay modes have been discovered, while others have been refined. An array of first observations, improvements, confirmations or limits are reported with respect to current world values. These higher precision and newly discovered decay modes are an excellent testing ground for recent theoretical interest in the contribution of higher Fock states and the color octet mechanism in heavy quarkonium annihilation and subsequent light hadronization. Because these calculations are largely tractable only in two body decays, these are the focus of this dissertation. A comparison of current theoretical calculations and experimental results is presented, indicating the success of these phenomenological advances. Measurements for which there are as yet no suitable theoretical prediction are indicated.

Beyond Diversity as Usual: Expanding Critical Cultural Approaches to Marginalization in Engineering Education

NASA Astrophysics Data System (ADS)

Secules, Stephen

In general, what we think of as "diversity work" in undergraduate engineering education focuses in the following ways: more on the overlooked assets of minority groups than on the acts of overlooking, more on the experiences of marginalized groups than on the mechanisms of marginalization by dominant groups, more on supporting and increasing minority student retention than on critiquing and remediating the systems which lead minority students to leave engineering. This dissertation presents a series of arguments which push beyond a status quo understanding of diversity in engineering education. The first approach the dissertation takes up is to problematize educational facts around failure by interrogating their roots in interactions and cultural norms in an engineering classroom. In another argument, the dissertation places the engineering classroom cultural norms of competition, whiteness, and masculinity in a critical historical context of the discipline at large. Finally, I demonstrate how engaging students in a critique of marginalizing educational culture can be an important source of agency. In addition to applying and demonstrating the value of specific novel approaches in engineering education, the dissertation contributes to the research community by discussing the respective affordances between these and other possible scholarly approaches to culture and marginalization in education. I also suggest how a consideration of the taken-for-granted culture of engineering education can be an important tool for instructors seeking to gain insight into persistent educational problems. In addition, this dissertation makes implications for diversity support practice, envisioning new forms of support programming rooted in intersectionality and critical praxis.

A Formal Investigation of Human Spatial Control Skills: Mathematical Formalization, Skill Development, and Skill Assessment

NASA Astrophysics Data System (ADS)

Li, Bin

Spatial control behaviors account for a large proportion of human everyday activities from normal daily tasks, such as reaching for objects, to specialized tasks, such as driving, surgery, or operating equipment. These behaviors involve intensive interactions within internal processes (i.e. cognitive, perceptual, and motor control) and with the physical world. This dissertation builds on a concept of interaction pattern and a hierarchical functional model. Interaction pattern represents a type of behavior synergy that humans coordinates cognitive, perceptual, and motor control processes. It contributes to the construction of the hierarchical functional model that delineates humans spatial control behaviors as the coordination of three functional subsystems: planning, guidance, and tracking/pursuit. This dissertation formalizes and validates these two theories and extends them for the investigation of human spatial control skills encompassing development and assessment. Specifically, this dissertation first presents an overview of studies in human spatial control skills encompassing definition, characteristic, development, and assessment, to provide theoretical evidence for the concept of interaction pattern and the hierarchical functional model. The following, the human experiments for collecting motion and gaze data and techniques to register and classify gaze data, are described. This dissertation then elaborates and mathematically formalizes the hierarchical functional model and the concept of interaction pattern. These theories then enables the construction of a succinct simulation model that can reproduce a variety of human performance with a minimal set of hypotheses. This validates the hierarchical functional model as a normative framework for interpreting human spatial control behaviors. The dissertation then investigates human skill development and captures the emergence of interaction pattern. The final part of the dissertation applies the hierarchical functional model for skill assessment and introduces techniques to capture interaction patterns both from the top down using their geometric features and from the bottom up using their dynamical characteristics. The validity and generality of the skill assessment is illustrated using two the remote-control flight and laparoscopic surgical training experiments.

The Nucleon Axial Form Factor and Staggered Lattice QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, Aaron Scott

The study of neutrino oscillation physics is a major research goal of the worldwide particle physics program over the upcoming decade. Many new experiments are being built to study the properties of neutrinos and to answer questions about the phenomenon of neutrino oscillation. These experiments need precise theoretical cross sections in order to access fundamental neutrino properties. Neutrino oscillation experiments often use large atomic nuclei as scattering targets, which are challenging for theorists to model. Nuclear models rely on free-nucleon amplitudes as inputs. These amplitudes are constrained by scattering experiments with large nuclear targets that rely on the very samemore » nuclear models. The work in this dissertation is the rst step of a new initiative to isolate and compute elementary amplitudes with theoretical calculations to support the neutrino oscillation experimental program. Here, the eort focuses on computing the axial form factor, which is the largest contributor of systematic error in the primary signal measurement process for neutrino oscillation studies, quasielastic scattering. Two approaches are taken. First, neutrino scattering data on a deuterium target are reanalyzed with a model-independent parametrization of the axial form factor to quantify the present uncertainty in the free-nucleon amplitudes. The uncertainties on the free-nucleon cross section are found to be underestimated by about an order of magnitude compared to the ubiquitous dipole model parametrization. The second approach uses lattice QCD to perform a rst-principles computation of the nucleon axial form factor. The Highly Improved Staggered Quark (HISQ) action is employed for both valence and sea quarks. The results presented in this dissertation are computed at physical pion mass for one lattice spacing. This work presents a computation of the axial form factor at zero momentum transfer, and forms the basis for a computation of the axial form factor momentum dependence with an extrapolation to the continuum limit and a full systematic error budget.« less

Assessing the Quality of PhD Dissertations. A Survey of External Committee Members

ERIC Educational Resources Information Center

Kyvik, Svein; Thune, Taran

2015-01-01

This article reports on a study of the quality assessment of doctoral dissertations, and asks whether examiner characteristics influence assessment of research quality in PhD dissertations. Utilising a multi-dimensional concept of quality of PhD dissertations, we look at differences in assessment of research quality, and particularly test whether…

Analyzing the Dissertations about Differentiated Instruction in Terms of Their Contents in Turkey

ERIC Educational Resources Information Center

Karip, Fatih

2016-01-01

This study aims to analyze the dissertations about differentiated instruction in terms of their contents in Turkey. The data of the study was collected from Council of Higher Education National Thesis Center database. The dissertations were searched without any year limitation. As a result of searching, 19 dissertations were found. The data…

Recurring Themes across Fractal Issues Facing International Students: A Thematic Analysis of 2016 Dissertations and Theses

ERIC Educational Resources Information Center

Bista, Krishna; Gaulee, Uttam

2017-01-01

This section shares recent dissertations and theses with the "Journal of International Students" readers. There were about 139 graduate dissertations and theses related to the issues and challenges of international students in 2016. The complete versions of these selected dissertations are available in the ProQuest, Michigan-based…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984 (Vol. 44, Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 dissertations abstracted deal with the following topics: (1) female managers' approaches to organizational conflict; (2) relationships between organizational climate and pupil control ideology; (3) information communication…

Experimental studies of MOS inversion and accumulation layers: Quantum mechanical effects and mobility

NASA Astrophysics Data System (ADS)

Chindalore, Gowrishankar L.

The development of fast, multi-functional, and energy efficient integrated circuits, is made possible by aggressively scaling the gate lengths of the MOS devices into the sub-quarter micron regime. However, with the increasing cost of fabrication, there is a strong need for the development of reliable and accurate device simulation capabilities. The development of the theoretical models for simulators is guided by extensive experimental data, which enable an experimental verification of the models, and lead to a better understanding of the underlying physics. This dissertation presents the methodology and the results for one such experimental effort, where two important physical effects in the inversion layer and the accumulation layer of a MOS device, namely, the quantum mechanical (QM) effects and the carrier mobility are investigated. Accordingly, this dissertation has been divided into two parts, with the first part discussing the increase in the threshold voltage and the accumulation electrical oxide thickness due to QM effects. The second part discusses the methodology and the experimental results for the extraction of the majority carrier mobilities in the accumulation layers of a MOSFET. The continued scaling of the MOS gate length requires decreased gate oxide thickness (tox) and increased channel doping (NB) in order to improve device performance while suppressing the short- channel effects. The combination of the two result in large enough transverse electric fields to cause significant quantization of the carriers in the potential well at the Si/SiO2 interface. Hence, compared to the classical calculations (where the QM effects are ignored), the QM effects are found to lead to an increase in the experimental threshold voltage by approximately 100mV, and an overestimation of the physical oxide thickness by approximately 3-4A, in MOSFET devices with a gate oxide thickness and the doping level anticipated for technologies with sub-quarter micron gate lengths. Thus, the experimental results indicate the need for using accurate QM models for simulating sub-quarter micron devices. Carrier mobility is a fundamental semiconductor device transport parameter that has been extensively characterized for both electrons and holes in the silicon bulk and MOS inversion layers. Accumulation layer mobility (μacc) has become increasingly important as the MOS devices have scaled to deep submicron gate lengths, and much effort has been required to achieve increased drive current. However, very little experimental data has been reported for carrier mobility in the MOS accumulation layers (Sun80, Man89). Hence, in this research work, the accumulation layer mobilities were extracted using buried-channel MOSFETs for both the electrons and holes, and for a wide range of doping levels at temperatures ranging from 25C to 150C. The experimental μacc is found to be greater than the corresponding bulk and the inversion layer mobilities, at low to moderate effective fields. However, at very high effective fields, where phonon and surface roughness scattering are dominant, the mobility behavior is found to be very similar to that of the inversion carriers. The extensive set of experimental data will enable the development of accurate local accumulation mobility models for inclusion in 2-D device simulators.

Heat transport by phonons in crystalline materials and nanostructures

NASA Astrophysics Data System (ADS)

Koh, Yee Kan

This dissertation presents experimental studies of heat transport by phonons in crystalline materials and nanostructures, and across solid-solid interfaces. Particularly, this dissertation emphasizes advancing understanding of the mean-free-paths (i.e., the distance phonons propagate without being scattered) of acoustic phonons, which are the dominant heat carriers in most crystalline semiconductor nanostructures. Two primary tools for the studies presented in this dissertation are time-domain thermoreflectance (TDTR) for measurements of thermal conductivity of nanostructures and thermal conductance of interfaces; and frequency-domain thermoreflectance (FDTR), which I developed as a direct probe of the mean-free-paths of dominant heat-carrying phonons in crystalline solids. The foundation of FDTR is the dependence of the apparent thermal conductivity on the frequency of periodic heat sources. I find that the thermal conductivity of semiconductor alloys (InGaP, InGaAs, and SiGe) measured by TDTR depends on the modulation frequency, 0.1 ≤ f ≤ 10 MHz, used in TDTR measurements. Reduction in the thermal conductivity of the semiconductor alloys at high f compares well to the reduction in the thermal conductivity of epitaxial thin films, indicating that frequency dependence and thickness dependence of thermal conductivity are fundamentally equivalent. I developed the frequency dependence of thermal conductivity into a convenient probe of phonon mean-free-paths, a technique which I call frequency-domain thermoreflectance (FDTR). In FDTR, I monitor the changes in the intensity of the reflected probe beam as a function of the modulation frequency. To facilitate the analysis of FDTR measurements, I developed a nonlocal theory for heat conduction by phonons at high heating frequencies. Calculations of the nonlocal theory confirm my experimental findings that phonons with mean-free-paths longer than two times the penetration depth do not contribute to the apparent thermal conductivity. I employed FDTR to study the mean-free-paths of acoustic phonons in Si1-xGex. I experimentally demonstrate that 40% of heat is carried in Si1-xGe x alloys by phonons with mean-free-path 0.5 ≤ ℓ ≤ 5 mum, and phonons with > 2 mum do not contribute to the thermal conductivity of Si. I employed TDTR and frequency-dependent TDTR to study scattering of long- and medium-wavelength phonons in two important thermoelectric materials embedded with nanoscale precipitates. I find that the through-thickness lattice thermal conductivity of (PbTe)1-x/(PbSe)x nanodot superlattices (NDSLs) approaches the thermal conductivity of bulk homogenous PbTe1-x Sex alloys with the same average composition. On the other hand, I find that 3% of ErAs nanoparticles embedded in InGaAs is sufficient to scatter most of the phonons in InGaAs that have intermediate mean-free-paths, and thus reduces the thermal conductivity of InGaAs below the alloy limit. I find that scattering by nanoparticles approach the geometrical limit and can be readily accounted for by an additional boundary scattering which depends on the concentration of nanoparticles. Finally, I studied the thermal conductance of Au/Ti/Graphene/SiO 2 interfaces by TDTR. I find that heat transport across the interface is dominated by phonons. Even though graphene is only one atomic layer thick, graphene interfaces should be treated as two discrete interfaces instead of one diffuse interface in thermal analysis, suggesting that direct transmission of phonons from Au to SiO2 is negligible. My study is important for thermal management of graphene devices.

Synchronous infrared imaging methods to characterize thermal properties of materials

NASA Astrophysics Data System (ADS)

Ouyang, Zhong

1999-11-01

A fundamental thermal property of a material is its thermal conductivity. The current state-of-the art for measurement of thermal conductivity is inadequate, especially in the case of composite materials. This dissertation addresses the need for a rapid and accurate measurement of thermal conductivity that can provide values for three orthogonal directions in a single measurement. The theoretical approach is based on three-dimensional thermal wave propagation and scattering treatments that have been developed earlier at Wayne State University. The experimental approach makes use of a state-of-the-art focal-plane-array infrared camera, which is used to follow the time- and spatial-progression of the planar heat pulse on both surfaces of the slab. The method has been used to determine the thermal diffusivity of six pure elemental single crystal materials (Cu, Ti, Bi, Al, Ag, Pb). The results are in good agreement (better than 1%) with the diffusivities calculated from the handbook. The diffusivities of some alloys and unidirectional graphite-fiber-reinforced-polymer composite also are determined by this method. As a byproduct of one of the experimental approaches measuring the IR radiation from the heated surface, direct evidence is obtained for the presence of a thermal wave "echo". The theory and confirming measurements in this dissertation represent its first clear confirmation. A second experimental method which is studied in this dissertation, and which may be used to characterize thermal properties of materials, is that of lock-in thermal wave imaging. In this technique, pioneered earlier at Wayne State University, a periodic heat source is applied to the surface of the material, and synchronous, phase-sensitive detection of the IR radiation from that surface is used to determine the effects of thermal wave propagation to subsurface features, and the effects of reflected thermal waves from those features on the observed IR radiation from the surface. The rationale for re-visiting this technique is the availability of the focal-plane-array IR camera, with its "snapshot" capability, its high spatial resolution, and its high pixel rate. A lock-in imaging method is developed for use with this camera, which can be used at frequencies that considerably exceed the maximum frame rate, with illustrative applications to characterize the thermal properties of printed circuits and electronic packages.

Converting STEM Doctoral Dissertations into Patent Applications: A Study of Chemistry, Physics, Mathematics, and Chemical Engineering Dissertations from CIC Institutions

ERIC Educational Resources Information Center

Butkovich, Nancy J.

2015-01-01

Doctoral candidates may request short-term embargoes on the release of their dissertations in order to apply for patents. This study examines how often inventions described in dissertations in chemical engineering, chemistry, physics, and mathematics are converted into U.S. patent applications, as well as the relationship between dissertation…

The Ph.D. Dissertation: An Analysis of the Doctoral Dissertation as an Information Source.

ERIC Educational Resources Information Center

Boyer, Calvin James

In 1972 American universities will confer 33,700 doctorates. An essential feature of the process which leads to the doctorate is the submission and defense of a dissertation. The doctoral dissertation must embody the results of extended research, be an original contribution to knowledge and include material worthy of publication. It is surprising,…

Digitizing dissertations for an institutional repository: a process and cost analysis.

PubMed

Piorun, Mary; Palmer, Lisa A

2008-07-01

This paper describes the Lamar Soutter Library's process and costs associated with digitizing 300 doctoral dissertations for a newly implemented institutional repository at the University of Massachusetts Medical School. Project tasks included identifying metadata elements, obtaining and tracking permissions, converting the dissertations to an electronic format, and coordinating workflow between library departments. Each dissertation was scanned, reviewed for quality control, enhanced with a table of contents, processed through an optical character recognition function, and added to the institutional repository. Three hundred and twenty dissertations were digitized and added to the repository for a cost of $23,562, or $0.28 per page. Seventy-four percent of the authors who were contacted (n = 282) granted permission to digitize their dissertations. Processing time per title was 170 minutes, for a total processing time of 906 hours. In the first 17 months, full-text dissertations in the collection were downloaded 17,555 times. Locally digitizing dissertations or other scholarly works for inclusion in institutional repositories can be cost effective, especially if small, defined projects are chosen. A successful project serves as an excellent recruitment strategy for the institutional repository and helps libraries build new relationships. Challenges include workflow, cost, policy development, and copyright permissions.

Optical properties of fly ash. Volume 2, Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Self, S.A.

1994-12-01

Research performed under this contract was divided into four tasks under the following headings: Task 1, Characterization of fly ash; Task 2, Measurements of the optical constants of slags; Task 3, Calculations of the radiant properties of fly ash dispersions; and Task 4, Measurements of the radiant properties of fly ash dispersions. Tasks 1 and 4 constituted the Ph.D. research topic of Sarbajit Ghosal, while Tasks 2 and 3 constituted the Ph.D. research topic of Jon Ebert. Together their doctoral dissertations give a complete account of the work performed. This final report, issued in two volumes consists of an executivemore » summary of the whole program followed by the dissertation of Ghosal and Ebert. Volume 2 contains the dissertation of Ebert which covers the measurements of the optical constants of slags, and calculations of the radiant properties of fly ash dispersions. A list of publications and conference presentations resulting from the work is also included.« less

Absolute surface reconstruction by slope metrology and photogrammetry

NASA Astrophysics Data System (ADS)

Dong, Yue

Developing the manufacture of aspheric and freeform optical elements requires an advanced metrology method which is capable of inspecting these elements with arbitrary freeform surfaces. In this dissertation, a new surface measurement scheme is investigated for such a purpose, which is to measure the absolute surface shape of an object under test through its surface slope information obtained by photogrammetric measurement. A laser beam propagating toward the object reflects on its surface while the vectors of the incident and reflected beams are evaluated from the four spots they leave on the two parallel transparent windows in front of the object. The spots' spatial coordinates are determined by photogrammetry. With the knowledge of the incident and reflected beam vectors, the local slope information of the object surface is obtained through vector calculus and finally yields the absolute object surface profile by a reconstruction algorithm. An experimental setup is designed and the proposed measuring principle is experimentally demonstrated by measuring the absolute surface shape of a spherical mirror. The measurement uncertainty is analyzed, and efforts for improvement are made accordingly. In particular, structured windows are designed and fabricated to generate uniform scattering spots left by the transmitted laser beams. Calibration of the fringe reflection instrument, another typical surface slope measurement method, is also reported in the dissertation. Finally, a method for uncertainty analysis of a photogrammetry measurement system by optical simulation is investigated.

Assessment of bachelor's theses in a nursing degree with a rubrics system: Development and validation study.

PubMed

González-Chordá, Víctor M; Mena-Tudela, Desirée; Salas-Medina, Pablo; Cervera-Gasch, Agueda; Orts-Cortés, Isabel; Maciá-Soler, Loreto

2016-02-01

Writing a bachelor thesis (BT) is the last step to obtain a nursing degree. In order to perform an effective assessment of a nursing BT, certain reliable and valid tools are required. To develop and validate a 3-rubric system (drafting process, dissertation, and viva) to assess final year nursing students' BT. A multi-disciplinary study of content validity and psychometric properties. The study was carried out between December 2014 and July 2015. Nursing Degree at Universitat Jaume I. Spain. Eleven experts (9 nursing professors and 2 education professors from 6 different universities) took part in the development and content validity stages. Fifty-two theses presented during the 2014-2015 academic year were included by consecutive sampling of cases in order to study the psychometric properties. First, a group of experts was created to validate the content of the assessment system based on three rubrics (drafting process, dissertation, and viva). Subsequently, a reliability and validity study of the rubrics was carried out on the 52 theses presented during the 2014-2015 academic year. The BT drafting process rubric has 8 criteria (S-CVI=0.93; α=0.837; ICC=0.614), the dissertation rubric has 7 criteria (S-CVI=0.9; α=0.893; ICC=0.74), and the viva rubric has 4 criteria (S-CVI=0.86; α=8.16; ICC=0.895). A nursing BT assessment system based on three rubrics (drafting process, dissertation, and viva) has been validated. This system may be transferred to other nursing degrees or degrees from other academic areas. It is necessary to continue with the validation process taking into account factors that may affect the results obtained. Copyright © 2015 Elsevier Ltd. All rights reserved.

Advances in adaptive control theory: Gradient- and derivative-free approaches

NASA Astrophysics Data System (ADS)

Yucelen, Tansel

In this dissertation, we present new approaches to improve standard designs in adaptive control theory, and novel adaptive control architectures. We first present a novel Kalman filter based approach for approximately enforcing a linear constraint in standard adaptive control design. One application is that this leads to alternative forms for well known modification terms such as e-modification. In addition, it leads to smaller tracking errors without incurring significant oscillations in the system response and without requiring high modification gain. We derive alternative forms of e- and adaptive loop recovery (ALR-) modifications. Next, we show how to use Kalman filter optimization to derive a novel adaptation law. This results in an optimization-based time-varying adaptation gain that reduces the need for adaptation gain tuning. A second major contribution of this dissertation is the development of a novel derivative-free, delayed weight update law for adaptive control. The assumption of constant unknown ideal weights is relaxed to the existence of time-varying weights, such that fast and possibly discontinuous variation in weights are allowed. This approach is particulary advantageous for applications to systems that can undergo a sudden change in dynamics, such as might be due to reconfiguration, deployment of a payload, docking, or structural damage, and for rejection of external disturbance processes. As a third and final contribution, we develop a novel approach for extending all the methods developed in this dissertation to the case of output feedback. The approach is developed only for the case of derivative-free adaptive control, and the extension of the other approaches developed previously for the state feedback case to output feedback is left as a future research topic. The proposed approaches of this dissertation are illustrated in both simulation and flight test.

High Contrast Astronomy with Starshades

NASA Astrophysics Data System (ADS)

Harness, Anthony D.

2016-09-01

One of the most important scientific discoveries to be had this century is the spectroscopic characterization of Earth-like exoplanets to determine the occurrence rate of worlds capable of supporting life and to potentially answer: are we alone in the universe? To accomplish these lofty goals requires an advancement in the technology to separate the overwhelming starlight from that of the exoplanet. I believe starshades are the key technology that will enable these discoveries within our lifetime. This dissertation work is a contribution to the advancement of starshade technology to put us on the path towards discovery. In this dissertation I present a number of suborbital methods developed for testing small-scale starshades, which include a Vertical Takeoff Vertical Landing rocket, the surface of a dry lake bed, and the heliostat of a solar telescope. The results from our high contrast observations are used to validate the optical model I developed to conduct tolerance analyses that will drive future starshade designs. The results from testing a formation flying sensor on the VTVL rocket demonstrate the rocket's potential for conducting starshade experiments in the stratosphere. This dissertation (along with [Novicki, et al. (2016)]) presents the first astronomical observations with a starshade that provide photometric measurements of stars, previously unobserved in the visible spectrum, in the proximity of Vega. These observations led to the development of a visual feedback system for the heliostat that allows us to push farther in separation and inner working angle. These high contrast observations were made using a starshade in the most flight-like configuration (in terms of Fresnel number, inner working angle, and resolution) to date. The results of this dissertation have helped demonstrate the effectiveness and practicality of starshades for starlight suppression and have outlined a path forward to further advance starshade technology through optical testing and high contrast astronomy.

Spooled packaging of shape memory alloy actuators

NASA Astrophysics Data System (ADS)

Redmond, John A.

A vast cross-section of transportation, manufacturing, consumer product, and medical technologies rely heavily on actuation. Accordingly, progress in these industries is often strongly coupled to the advancement of actuation technologies. As the field of actuation continues to evolve, smart materials show significant promise for satisfying the growing needs of industry. In particular, shape memory alloy (SMA) wire actuators present an opportunity for low-cost, high performance actuation, but until now, they have been limited or restricted from use in many otherwise suitable applications by the difficulty in packaging the SMA wires within tight or unusually shaped form constraints. To address this packaging problem, SMA wires can be spool-packaged by wrapping around mandrels to make the actuator more compact or by redirecting around multiple mandrels to customize SMA wire pathways to unusual form factors. The goal of this dissertation is to develop the scientific knowledge base for spooled packaging of low-cost SMA wire actuators that enables high, predictable performance within compact, customizable form factors. In developing the scientific knowledge base, this dissertation defines a systematic general representation of single and multiple mandrel spool-packaged SMA actuators and provides tools for their analysis, understanding, and synthesis. A quasi-static analytical model distills the underlying mechanics down to the three effects of friction, bending, and binding, which enables prediction of the behavior of generic spool-packaged SMA actuators with specifiable geometric, loading, frictional, and SMA material parameters. An extensive experimental and simulation-based parameter study establishes the necessary understanding of how primary design tradeoffs between performance, packaging, and cost are governed by the underlying mechanics of spooled actuators. A design methodology outlines a systematic approach to synthesizing high performance SMA wire actuators with mitigated material, power, and packaging costs and compact, customizable form factors. By examining the multi-faceted connections between performance, packaging, and cost, this dissertation builds a knowledge base that goes beyond implementing SMA actuators for particular applications. Rather, it provides a well-developed strategy for realizing the advantages of SMA actuation for a broadened range of applications, thereby enabling opportunities for new functionality and capabilities in industry.

Real-Time Monitoring and Prediction of the Pilot Vehicle System (PVS) Closed-Loop Stability

NASA Astrophysics Data System (ADS)

Mandal, Tanmay Kumar

Understanding human control behavior is an important step for improving the safety of future aircraft. Considerable resources are invested during the design phase of an aircraft to ensure that the aircraft has desirable handling qualities. However, human pilots exhibit a wide range of control behaviors that are a function of external stimulus, aircraft dynamics, and human psychological properties (such as workload, stress factor, confidence, and sense of urgency factor). This variability is difficult to address comprehensively during the design phase and may lead to undesirable pilot-aircraft interaction, such as pilot-induced oscillations (PIO). This creates the need to keep track of human pilot performance in real-time to monitor the pilot vehicle system (PVS) stability. This work focused on studying human pilot behavior for the longitudinal axis of a remotely controlled research aircraft and using human-in-the-loop (HuIL) simulations to obtain information about the human controlled system (HCS) stability. The work in this dissertation is divided into two main parts: PIO analysis and human control model parameters estimation. To replicate different flight conditions, this study included time delay and elevator rate limiting phenomena, typical of actuator dynamics during the experiments. To study human control behavior, this study employed the McRuer model for single-input single-output manual compensatory tasks. McRuer model is a lead-lag controller with time delay which has been shown to adequately model manual compensatory tasks. This dissertation presents a novel technique to estimate McRuer model parameters in real-time and associated validation using HuIL simulations to correctly predict HCS stability. The McRuer model parameters were estimated in real-time using a Kalman filter approach. The estimated parameters were then used to analyze the stability of the closed-loop HCS and verify them against the experimental data. Therefore, the main contribution of this dissertation is the design of an unscented Kalman filter-based algorithm to estimate McRuer model parameters in real time, and a framework to validate this algorithm for single-input single-output manual compensatory tasks to predict instabilities.

Development of shape memory alloy (SMA) torsional actuators for variable twist tilt rotor (VTTR) blades

NASA Astrophysics Data System (ADS)

Prahlad, Harsha

This dissertation presents the development of a torsional actuator to alter the twist distributions of a tiltrotor blade between hover and forward flight. The actuator uses a Shape Memory Alloy (SMA) tube as its active element. The historical development of the tiltrotor aircraft is discussed, with emphasis on advanced tiltrotor concepts. The central theme in these concepts is to reduce the compromises for tiltrotor blade design, thereby improving performance of the aircraft in both hover and forward flight modes. A survey of research conducted in the application of smart structures to performance enhancement of aircraft is conducted. A review of other torsional actuators that are based on SMAs is presented. An assessment of the state-of-the-art in SMA modeling and characterization, both in mechanical tensile and torsional loading, is also discussed. Shape Memory Alloys are "smart" actuation materials that are capable of providing high stroke and high force of actuation at relatively low bandwidth. However, their behavior is complex, and influenced by material non-linearities, thermo-mechanical conditions and history of loading. In addition, the behavior of torsional SMA actuators has not been investigated in detail. In order to address these issues, the current research carries out a comprehensive characterization of SMAs. Experimental characteristics of SMA wires under extensional loading, and SMA rods and tubes in both extensional and torsional loading under a variety of thermo-mechanical conditions are presented in this dissertation. It is demonstrated that the uniaxial quasistatic SMA models show good overall agreement with the experimental behavior of an SMA wire under extensional loading. In addition, an approach that incorporates these models with radial non-uniformity due to torsional deflections is shown to provide good predictions of torsional characteristics of SMA rods and tubes. Several differences of the material response under non-quasistatic loading conditions are also shown. A modeling technique that predicts these effects by coupling the material phenomenology with an energy equilibrium analysis is proposed. In addition, a theoretical and experimental study involving composite laminates with embedded SMAs is also presented in this work. The concept of tuning the natural frequencies of a composite structure using embedded SMAs is demonstrated, and associated manufacturing issues discussed. Using the concepts developed in the study on SMAs, a torsional actuator involving an SMA tube is developed for the proposed application. The design of the heat transfer and torque transfer assemblies for the actuator is described. Benchtop testing of the actuator shows the feasibility of this actuator in applications involving large recovery torques of actuation. It is demonstrated that using the current concept, one actuator is not sufficient to meet the twist actuation requirements for a full-scale tiltrotor blade. However, a modification in the blade torsional stiffness, in conjunction with the use of two discrete SMA actuators, may render the concept feasible for a full-scale tiltrotor.

LAD Dissertation Prize Talk: Molecular Collisional Excitation in Astrophysical Environments

NASA Astrophysics Data System (ADS)

Walker, Kyle M.

2017-06-01

While molecular excitation calculations are vital in determining particle velocity distributions, internal state distributions, abundances, and ionization balance in gaseous environments, both theoretical calculations and experimental data for these processes are lacking. Reliable molecular collisional data with the most abundant species - H2, H, He, and electrons - are needed to probe material in astrophysical environments such as nebulae, molecular clouds, comets, and planetary atmospheres. However, excitation calculations with the main collider, H2, are computationally expensive and therefore various approximations are used to obtain unknown rate coefficients. The widely-accepted collider-mass scaling approach is flawed, and alternate scaling techniques based on physical and mathematical principles are presented here. The most up-to-date excitation data are used to model the chemical evolution of primordial species in the Recombination Era and produce accurate non-thermal spectra of the molecules H2+, HD, and H2 in a primordial cloud as it collapses into a first generation star.

Computational aeroacoustics and numerical simulation of supersonic jets

NASA Technical Reports Server (NTRS)

Morris, Philip J.; Long, Lyle N.

1996-01-01

The research project has been a computational study of computational aeroacoustics algorithms and numerical simulations of the flow and noise of supersonic jets. During this study a new method for the implementation of solid wall boundary conditions for complex geometries in three dimensions has been developed. In addition, a detailed study of the simulation of the flow in and noise from supersonic circular and rectangular jets has been conducted. Extensive comparisons have been made with experimental measurements. A summary of the results of the research program are attached as the main body of this report in the form of two publications. Also, the report lists the names of the students who were supported by this grant, their degrees, and the titles of their dissertations. In addition, a list of presentations and publications made by the Principal Investigators and the research students is also included.

Modeling and control of hybrid wind/photovoltaic/fuel cell distributed generation systems

NASA Astrophysics Data System (ADS)

Wang, Caisheng

Due to ever increasing energy consumption, rising public awareness of environmental protection, and steady progress in power deregulation, alternative (i.e., renewable and fuel cell based) distributed generation (DG) systems have attracted increased interest. Wind and photovoltaic (PV) power generation are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show great potential in DG applications of the future due to their fast technology development and many merits they have, such as high efficiency, zero or low emission (of pollutant gases) and flexible modular structure. The modeling and control of a hybrid wind/PV/FC DG system is addressed in this dissertation. Different energy sources in the system are integrated through an AC bus. Dynamic models for the main system components, namely, wind energy conversion system (WECS), PV energy conversion system (PVECS), fuel cell, electrolyzer, power electronic interfacing circuits, battery, hydrogen storage tank, gas compressor and gas pressure regulator, are developed. Two types of fuel cells have been modeled in this dissertation: proton exchange membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC). Power control of a grid-connected FC system as well as load mitigation control of a stand-alone FC system are investigated. The pitch angle control for WECS, the maximum power point tracking (MPPT) control for PVECS, and the control for electrolyzer and power electronic devices, are also addressed in the dissertation. Based on the dynamic component models, a simulation model for the proposed hybrid energy system has been developed using MATLAB/Simulink. The overall power management strategy for coordinating the power flows among the different energy sources is presented in the dissertation. Simulation studies have been carried out to verify the system performance under different scenarios using a practical load profile and real weather data. The results show that the overall power management strategy is effective and the power flows among the different energy sources and the load demand is balanced successfully. The DG's impacts on the existing power system are also investigated in this dissertation. Analytical methods for finding optimal sites to deploy DG sources in power systems are presented and verified with simulation studies.

Students' explanations in complex learning of disciplinary programming

NASA Astrophysics Data System (ADS)

Vieira, Camilo

Computational Science and Engineering (CSE) has been denominated as the third pillar of science and as a set of important skills to solve the problems of a global society. Along with the theoretical and the experimental approaches, computation offers a third alternative to solve complex problems that require processing large amounts of data, or representing complex phenomena that are not easy to experiment with. Despite the relevance of CSE, current professionals and scientists are not well prepared to take advantage of this set of tools and methods. Computation is usually taught in an isolated way from engineering disciplines, and therefore, engineers do not know how to exploit CSE affordances. This dissertation intends to introduce computational tools and methods contextualized within the Materials Science and Engineering curriculum. Considering that learning how to program is a complex task, the dissertation explores effective pedagogical practices that can support student disciplinary and computational learning. Two case studies will be evaluated to identify the characteristics of effective worked examples in the context of CSE. Specifically, this dissertation explores students explanations of these worked examples in two engineering courses with different levels of transparency: a programming course in materials science and engineering glass box and a thermodynamics course involving computational representations black box. Results from this study suggest that students benefit in different ways from writing in-code comments. These benefits include but are not limited to: connecting xv individual lines of code to the overall problem, getting familiar with the syntax, learning effective algorithm design strategies, and connecting computation with their discipline. Students in the glass box context generate higher quality explanations than students in the black box context. These explanations are related to students prior experiences. Specifically, students with low ability to do programming engage in a more thorough explanation process than students with high ability. This dissertation concludes proposing an adaptation to the instructional principles of worked-examples for the context of CSE education.

Axiomatic Evaluation Method and Content Structure for Information Appliances

ERIC Educational Resources Information Center

Guo, Yinni

2010-01-01

Extensive studies have been conducted to determine how best to present information in order to enhance usability, but not what information is needed to be presented for effective decision making. Hence, this dissertation addresses the factor structure of the nature of information needed for presentation and proposes a more effective method than…

Digitizing Dissertations for an Institutional Repository: A Process and Cost Analysis*

PubMed Central

Piorun, Mary; Palmer, Lisa A.

2008-01-01

Objective: This paper describes the Lamar Soutter Library's process and costs associated with digitizing 300 doctoral dissertations for a newly implemented institutional repository at the University of Massachusetts Medical School. Methodology: Project tasks included identifying metadata elements, obtaining and tracking permissions, converting the dissertations to an electronic format, and coordinating workflow between library departments. Each dissertation was scanned, reviewed for quality control, enhanced with a table of contents, processed through an optical character recognition function, and added to the institutional repository. Results: Three hundred and twenty dissertations were digitized and added to the repository for a cost of $23,562, or $0.28 per page. Seventy-four percent of the authors who were contacted (n = 282) granted permission to digitize their dissertations. Processing time per title was 170 minutes, for a total processing time of 906 hours. In the first 17 months, full-text dissertations in the collection were downloaded 17,555 times. Conclusion: Locally digitizing dissertations or other scholarly works for inclusion in institutional repositories can be cost effective, especially if small, defined projects are chosen. A successful project serves as an excellent recruitment strategy for the institutional repository and helps libraries build new relationships. Challenges include workflow, cost, policy development, and copyright permissions. PMID:18654648

Cyber-Surveillance: A Case Study in Policy and Development

ERIC Educational Resources Information Center

Kim, Richard S. Y.

2010-01-01

The dissertation examines the historical development of surveillance, electronic surveillance, and cyber-surveillance from colonial times in the United States to the present. It presents the surveillance laws, technologies and policies as a balance between national security and privacy. To examine more recent developments, the dissertation…

Fifty Years of Promoting Library History: A Chronology of the ALA (American) Library History Round Table, 1947-1997.

ERIC Educational Resources Information Center

Wertheimer, Andrew B.; Marshall, John David

2000-01-01

Presents a chronology of the Library History Round Table of the American Library Association. Includes topics and presenters of programs; awards, including the Justin Winsor Prize and the Phyllis Dain Library Dissertation Award; and leadership. (LRW)

[Knowledge, strategies and ideologies of nursing: a reflection based on the Lopes' study].

PubMed

Costa, I G; Gomes, E L

2001-01-01

This paper makes a reflection on the knowledge and ideologies present in the nursing practice within a hospital context, based on theoretical references used by the sociologist Noemia da Glória Mendes Lopes in her MS dissertation in Lisbon, Portugal, in 1994. In this dissertation she analyzes the work of nurses within hospital contexts. The author observed that within the professional context of nursing there are many social practices of work indicating different strategies of valuing and revaluating the profession. It was concluded from this reflection that there are better possibilities of performing such strategies in specialized services than in medical clinic services.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Barton; Schultz, Richard

The results of this project are best described by the papers and dissertations that resulted from the work. They are included in their entirety in this document. They are: (1) Jeff Harris PhD dissertation (focused mainly on forced convection); (2) Blake Lance PhD dissertation (focused mainly on mixed and transient convection). This dissertation is in multi-paper format and includes the article currently submitted and one to be submitted shortly; and, (3) JFE paper on CFD Validation Benchmark for Forced Convection.

[The list of literature (review) on studying urinary stones by russian researchers (Dated between 1965 and 2015, in 2 parts) Part I].

PubMed

Polienko, A K; Boshchenko, V S; Sevost'yanova, O A

2016-02-01

Urolithiasis is one of the most common urological diseases. Determination of mineral composition and structure of urinary stones is necessary for urologists to provide targeted therapeutic and preventive measures. Existing global standards for management of kidney stones require analysis of stone composition to be done for each urolithiasis patient. The list of literature representing the scientific work of the Russian scientists on studying the mineral composition and structure of urinary stones, includes articles, abstracts, monographs, dissertations presented as reports and presentations at conferences and seminars (mineralogical and urological). Over half a century (1965-2015) there were 178 articles published in geological and urological journals, 7 published monographs and 8 defended dissertations (2 on Medical Sciences and 6 on Geological and Mineralogical Sciences).

Thermo-mechanical properties and integrity of metallic interconnects in microelectronics

NASA Astrophysics Data System (ADS)

Ege, Efe Sinan

In this dissertation, combined numerical (Finite Element Method) and experimental efforts were undertaken to study thermo-mechanical behavior in microelectronic devices. Interconnects, including chip-level metallization and package-level solder joints, are used to join many of the circuit parts in modern equipment. The dissertation is structured into six independent studies after the introductory chapter. The first two studies focus on thermo-mechanical fatigue of solder joints. Thermo-mechanical fatigue, in the form of damage along a microstructurally coarsened region in tin-lead solder, is analyzed along with the effects of intermetallic morphology. Also, lap-shear testing is modeled to characterize the joint and to investigate the validity of experimental data from different solder and substrate geometries. In the third study, the effects of pre-machined holes on strain localization and overall ductility in bulk eutectic tin-lead alloy is examined. Finite element analyses, taking into account the viscoplastic response, were carried out to provide a mechanistic rationale to corroborate the experimental findings. The fourth study concerns chip-level copper interconnects. Various combinations of oxide and polymer-based low-k dielectric schemes, with and without the thin barrier layers surrounding the Cu line, are considered. Attention is devoted to the thermal stress and strain fields and their dependency on material properties, geometry, and modeling details. This study is followed by a chapter on atomistics of interface-mediated plasticity in thin metallic films. The objective is to gain fundamental insight into the underlying mechanisms affecting the mechanical response of nanoscale thin films. The final study investigates the effect of microstructural heterogeneity on indentation response, for the purpose of raising awareness of the uncertainties involved in applying indentation techniques in probing mechanical properties of miniaturized devices.

Dynamic response of a collidant impacting a low pressure airbag

NASA Astrophysics Data System (ADS)

Dreher, Peter A.

There are many uses of low pressure airbags, both military and commercial. Many of these applications have been hampered by inadequate and inaccurate modeling tools. This dissertation contains the derivation of a four degree-of-freedom system of differential equations from physical laws of mass and energy conservation, force equilibrium, and the Ideal Gas Law. Kinematic equations were derived to model a cylindrical airbag as a single control volume impacted by a parallelepiped collidant. An efficient numerical procedure was devised to solve the simplified system of equations in a manner amenable to discovering design trends. The largest public airbag experiment, both in scale and scope, was designed and built to collect data on low-pressure airbag responses, otherwise unavailable in the literature. The experimental results were compared to computational simulations to validate the simplified numerical model. Experimental response trends are presented that will aid airbag designers. The two objectives of using a low pressure airbag to demonstrate the feasibility to (1) accelerate a munition to 15 feet per second velocity from a bomb bay, and (2) decelerate humans hitting trucks below the human tolerance level of 50 G's, were both met.

GIFAD for He/KCl(001). Structure in the pattern for 〈 110 〉 incidence as a measure of the projectile-cation interaction

NASA Astrophysics Data System (ADS)

Bocan, G. A.; Gravielle, M. S.

2018-04-01

In this article we address grazing incidence fast atom diffraction (GIFAD) for the He/KCl(001) system, for which a systematic experimental study was recently reported [E. Meyer, Ph.D dissertation, Humboldt-Universität, Berlin, Germany, 2015]. Our theoretical model is built from a projectile-surface interaction obtained from Density Functional Theory (DFT) calculations and the Surface Initial-Value Representation (SIVR), which is a semi-quantum approach to describe the scattering process. For incidence along the 〈 100 〉 and 〈 110 〉 directions, we present and discuss the main features of our interaction potential, the dependence of the rainbow angle with the impact energy normal to the surface, and the simulated GIFAD patterns, which reproduce the main aspects of the reported experimental charts. The features of the diffraction charts for He/KCl(001) are related to the averaged equipotential curves of the system and a comparison is established with the case of He/LiF(001). The marked differences observed for 〈 110 〉 incidence are explained as due to the much larger size of the K+ ion relative to that of Li+.

Research in Physical Chemistry and Chemical Education: Part A--Water Mediated Chemistry of Oxidized Atmospheric Compounds Part B--The Development of Surveying Tools to Determine How Effective Laboratory Experiments Contribute to Student Conceptual Understanding

ERIC Educational Resources Information Center

Maron, Marta Katarzyna

2011-01-01

This dissertation is a combination of two research areas, experimental physical chemistry, Chapters I to V, and chemical education, Chapters VI to VII. Chapters I to V describe research on the water-mediated chemistry of oxidized atmospheric molecules and the impact that water has on the spectra of these environmental systems. The role of water…

Galaxy Transformation Under Extreme Conditions: The Evolution of Galaxies in the Largest Structures in the High Redshift Universe

NASA Astrophysics Data System (ADS)

Lemaux, Brian Clark

This dissertation describes research performed in the field of observational astrophysics as part of the Observations of Redshift Evolution in Large Scale Environment (ORELSE) survey. The general motivation of the research presented in this dissertation is to investigate the processes responsible for the evolution of galaxies in a wide range of physical conditions over cosmic time. Throughout this dissertation, galaxy populations will be considered in the very nearby universe (i.e., within one billion light years from Earth), the middle-aged universe (i.e., eight billion years ago), and in the very early universe (i.e., just one billion years after the beginning of the universe). In each chapter I present unique data from observations taken and analyzed specifically for the ORELSE survey. In the first part of this dissertation I describe the context, aims, and current state of the ORELSE survey. The studies presented in this dissertation span a large range of galaxy samples and investigate a variety of different astrophysical phenomena. As all of these studies fall under the context of galaxy evolution, these initial sections will set the framework for the variety of studies presented in this thesis. In the second part of this dissertation I present four studies undertaken to investigate various aspects of galaxy evolution. The first of these studies is an investigation of a large population of very distant galaxies detected in one of the ORELSE fields. The survey in this field represents the deepest survey of a particular kind of very distant galaxy population known as Lymanalpha Emitter (LAEs). The number of LAEs found in this survey far exceeded expectations for such galaxies and are shown to be in excess of every other survey of similar galaxies at similar distances. This result has important consequences for galaxy evolution studies, as it suggests that faint LAEs may be much more numerous than previously thought. This work also has important consequences for a process in the early universe known as reionization, which is the subject of much debate amongst astronomers. The second and third of these studies are investigations using near-infrared spectroscopy of X-ray bright and red galaxies that exhibit optical spectra with prominent emission features. These studies are the first systematic investigations of both galaxy populations in the middle-aged universe using near-infrared spectroscopy. In both studies I conclude the dominant mechanism giving rise to optical emission line features are processes associated with the presence of an Active Galactic Nuclei (AGN) rather than normal star formation. This result has important consequences for galaxy evolutionary scenarios, as the two processes are typically difficult to separate observationally and are thought to be related. The final study in this presentation is a full investigation of the processes driving galaxy evolution in one of the ORELSE fields, the Cl1604 supercluster. In this study I present the wealth of astronomical observations available to the ORELSE survey on the member galaxies of this supercluster. Several transitional populations of galaxies are detected in the supercluster environment, and their properties are analyzed in the context of galaxy evolution. Processing of the galaxy population is found to be significant in both the densest environments in the supercluster and the lower-density regions. One of the major conclusions of this work relates to the efficiency of these transformative processes and the global environment in which a galaxy resides. I present evidence for a process termed "dynamical downsizing", in which efficient transforming of galaxies occurs earliest in structures of galaxies that are observed to be relaxed (i.e., virialized) in their dynamics.

High Resolution Spectra of Carbon Monoxide, Propane and Ammonia for Atmospheric Remote Sensing

NASA Astrophysics Data System (ADS)

Beale, Christopher Andrew

Spectroscopy is a critical tool for analyzing atmospheric data. Identification of atmospheric parameters such as temperature, pressure and the existence and concentrations of constituent gases via remote sensing techniques are only possible with spectroscopic data. These form the basis of model atmospheres which may be compared to observations to determine such parameters. To this end, this dissertation explores the spectroscopy of three molecules: ammonia, propane and carbon monoxide. Infrared spectra have been recorded for ammonia in the region 2400-9000 cm-1. These spectra were recorded at elevated temperatures (from 293-973 K) using a Fourier Transform Spectrometer (FTS). Comparison between the spectra recorded at different temperatures yielded experimental lower state energies. These spectra resulted in the measurement of roughly 30000 lines and about 3000 quantum assignments. In addition spectra of propane were recorded at elevated temperatures (296-700 K) using an FTS. Atmospheres with high temperatures require molecular data at appropriate conditions. This dissertation describes collection of such data and the potential application to atmospheres in our solar system, such as auroral regions in Jupiter, to those of planets orbiting around other stars and cool sub-stellar objects known as brown dwarfs. The spectra of propane and ammonia provide the highest resolution and most complete experimental study of these gases in their respective spectral regions at elevated temperatures. Detection of ammonia in an exoplanet or detection of propane in the atmosphere of Jupiter will most likely rely on the work presented here. The best laboratory that we have to study atmospheres is our own planet. The same techniques that are applied to these alien atmospheres originated on Earth. As such it is appropriate to discuss remote sensing of our own atmosphere. This idea is explored through analysis of spectroscopic data recorded by an FTS on the Atmospheric Chemistry Experiment satellite of carbon monoxide. The effect of the atmosphere's chemistry and physics on this molecule is measured through its isotopologues, primarily 13CO (carbon-13 substituted carbon monoxide). Isotopic chemistry allows a key analysis of the atmosphere as it may be used as a tracer for chemical reactions and dynamical processes. The carbon monoxide fractionation results in Chapter IV present the first global measurements of isotopic fractionation of CO, showing significant fractionation in the upper atmosphere (60-80 km) as a result of the photolysis of carbon dioxide (CO2).

Dynamic Photorefractive Memory and its Application for Opto-Electronic Neural Networks.

NASA Astrophysics Data System (ADS)

Sasaki, Hironori

This dissertation describes the analysis of the photorefractive crystal dynamics and its application for opto-electronic neural network systems. The realization of the dynamic photorefractive memory is investigated in terms of the following aspects: fast memory update, uniform grating multiplexing schedules and the prevention of the partial erasure of existing gratings. The fast memory update is realized by the selective erasure process that superimposes a new grating on the original one with an appropriate phase shift. The dynamics of the selective erasure process is analyzed using the first-order photorefractive material equations and experimentally confirmed. The effects of beam coupling and fringe bending on the selective erasure dynamics are also analyzed by numerically solving a combination of coupled wave equations and the photorefractive material equation. Incremental recording technique is proposed as a uniform grating multiplexing schedule and compared with the conventional scheduled recording technique in terms of phase distribution in the presence of an external dc electric field, as well as the image gray scale dependence. The theoretical analysis and experimental results proved the superiority of the incremental recording technique over the scheduled recording. Novel recirculating information memory architecture is proposed and experimentally demonstrated to prevent partial degradation of the existing gratings by accessing the memory. Gratings are circulated through a memory feed back loop based on the incremental recording dynamics and demonstrate robust read/write/erase capabilities. The dynamic photorefractive memory is applied to opto-electronic neural network systems. Module architecture based on the page-oriented dynamic photorefractive memory is proposed. This module architecture can implement two complementary interconnection organizations, fan-in and fan-out. The module system scalability and the learning capabilities are theoretically investigated using the photorefractive dynamics described in previous chapters of the dissertation. The implementation of the feed-forward image compression network with 900 input and 9 output neurons with 6-bit interconnection accuracy is experimentally demonstrated. Learning of the Perceptron network that determines sex based on input face images of 900 pixels is also successfully demonstrated.

Detection and Classification of Whale Acoustic Signals

NASA Astrophysics Data System (ADS)

Xian, Yin

This dissertation focuses on two vital challenges in relation to whale acoustic signals: detection and classification. In detection, we evaluated the influence of the uncertain ocean environment on the spectrogram-based detector, and derived the likelihood ratio of the proposed Short Time Fourier Transform detector. Experimental results showed that the proposed detector outperforms detectors based on the spectrogram. The proposed detector is more sensitive to environmental changes because it includes phase information. In classification, our focus is on finding a robust and sparse representation of whale vocalizations. Because whale vocalizations can be modeled as polynomial phase signals, we can represent the whale calls by their polynomial phase coefficients. In this dissertation, we used the Weyl transform to capture chirp rate information, and used a two dimensional feature set to represent whale vocalizations globally. Experimental results showed that our Weyl feature set outperforms chirplet coefficients and MFCC (Mel Frequency Cepstral Coefficients) when applied to our collected data. Since whale vocalizations can be represented by polynomial phase coefficients, it is plausible that the signals lie on a manifold parameterized by these coefficients. We also studied the intrinsic structure of high dimensional whale data by exploiting its geometry. Experimental results showed that nonlinear mappings such as Laplacian Eigenmap and ISOMAP outperform linear mappings such as PCA and MDS, suggesting that the whale acoustic data is nonlinear. We also explored deep learning algorithms on whale acoustic data. We built each layer as convolutions with either a PCA filter bank (PCANet) or a DCT filter bank (DCTNet). With the DCT filter bank, each layer has different a time-frequency scale representation, and from this, one can extract different physical information. Experimental results showed that our PCANet and DCTNet achieve high classification rate on the whale vocalization data set. The word error rate of the DCTNet feature is similar to the MFSC in speech recognition tasks, suggesting that the convolutional network is able to reveal acoustic content of speech signals.

Combining research in physical chemistry and chemical education: Part A. The femtosecond molecular dynamics of small gas-phase anion clusters. Part B. Surveying student beliefs about chemistry and the development of physical chemistry learning tutorials

NASA Astrophysics Data System (ADS)

Barbera, Jack

2007-12-01

This dissertation combines work in the areas of experimental physical chemistry and chemical education. In the area of physical chemistry, femtosecond pump-probe spectroscopy is used to interrogate the time-dependence for energy redistribution, solvent reorientation, and dissociation dynamics in small gas-phase anion clusters. The chemical education research addressed in this manuscript include the development and validation of a survey to measure students' beliefs about chemistry and the learning of chemistry and the development and testing of learning tutorials for use in undergraduate physical chemistry courses in thermodynamics and kinetics. In the first part of this dissertation, the Cu(CD3OD) dynamics are investigated using a combination of femtosecond pump-probe experiments and ab initio calculations. Dissociation of this complex into Cu and CD3OD occurs on two distinct time scales: 3 and 30 ps, which arise, respectively, from the coupling of intermolecular solvent rotations and excited methyl rotor rotation into the Cu-O dissociation component upon electron photodetachment of the precursor anion. In the second part of this dissertation, the time-resolved recombination of photodissociated IBr-(CO2)n (n = 5 - 10) cluster anions is investigated. Upon excitation to the A' 2pi 1/2 state of the chromophore, the bare anion results in I- and Br products, upon solvation with CO2, the IBr- chromophore regains near-IR absorption after recombination and vibrational relaxation on the ground electronic state. The recombination times vary with the number of solvent molecules from 12 ps for n = 5 to 900 ps for n = 10. Extensive electronic structure and non-adiabatic molecular dynamic simulations provide a framework to understand this behavior. In the third part of this dissertation, the modification and validation of the Colorado Learning Attitudes about Science Survey (CLASS) for use in chemistry is presented in detail. The CLASS survey is designed to measure student beliefs about chemistry and the learning of chemistry. This instrument is a modification of the original CLASS-Phys survey designed for use in physics. Statements on the chemistry version (CLASS-Chem) are validated using chemistry students with a broad range of experience levels to ensure clarity in wording and meaning. The chemistry version addresses additional belief areas important in learning chemistry but not physics, specifically, beliefs about reactions and molecular structure. Statements are grouped into statistically robust categories using reduced basis factor analysis. The final part of this dissertation addresses the development and testing of learning tutorials for use in undergraduate physical chemistry. The tutorials are designed to promote the active mental engagement of students in the process of learning. Questions within the pencil-paper format guide students through the reasoning needed to apply concepts to real-world situations. Each tutorial is connected to a physical model or computer simulation providing students with additional hands-on investigations to strengthen their connection with the concepts addressed in the tutorial. Currently tutorials connected with the First and Second Laws of Thermodynamics as well as Kinetics have been developed and tested.

Making Time for Dissertation Grants

PubMed Central

Hasche, Leslie K.; Perron, Brian E.; Proctor, Enola K.

2013-01-01

Grant writing is a necessary skill for becoming an independent and successful social work researcher. Since social work dissertation grants are a relatively new trend, students face many challenges in identifying, preparing, and submitting dissertation grants. Lack of resources and experiences, difficulties in protecting time for grant writing, and the uncertainty of success can hinder work on dissertation grants. Thus, this article provides an overview of dissertation grants, including a review of grant mechanisms, suggestions for preparing grants in the context of program milestones, and identifying institutional infrastructure to facilitate submissions. Strategies discussed include how to learn about funding priorities, how to establish timelines to account for grant deadlines, and how to use peer reviews to guide the revision process. PMID:24244078

Integrating Multimedia Instructional Design Principles with Complex Physiological Concepts in Reproductive Science

ERIC Educational Resources Information Center

Oki, Angela Christine

2011-01-01

This dissertation examines the effect of digital multimedia presentations as a method to teach complex concepts in reproductive physiology. The digital presentations developed for this research consisted of two-dimensional (2-D) and three-dimensional (3-D) animations, scriptmessaging and narration. The topics were "Mammalian Ovarian…

Water Quantity and Quality Processes in Urban Wetlands and Green Stormwater Management Practices

EPA Science Inventory

I have been invited to give a presentation as part of the Environmental Studies Program’s weekly seminar series at the Richard Stockton College in Pomona, NJ. I will present my dissertation research on urban wetlands and the green infrastructure research here, including the park...

Automatic Presentation of Sense-Specific Lexical Information in an Intelligent Learning System

ERIC Educational Resources Information Center

Eom, Soojeong

2012-01-01

Learning vocabulary and understanding texts present difficulty for language learners due to, among other things, the high degree of lexical ambiguity. By developing an intelligent tutoring system, this dissertation examines whether automatically providing enriched sense-specific information is effective for vocabulary learning and reading…

Examining Teacher Turnover: Past and Present

ERIC Educational Resources Information Center

Connor, Rob

2011-01-01

This dissertation presents a framework for investigating how school level phenomena may influence African-American teacher retention, attrition, and mobility in K-12 contexts. I argue that prevalent assumptions and inadequate data concerning the state of black educators have inhibited thorough investigation of minority employment trends in K-12…

The Effects of Frequency, Distribution, Mode of Presentation, and First Language on Learning an Artificial Language

ERIC Educational Resources Information Center

Miyata, Munehiko

2011-01-01

This dissertation presents results from a series of experiments investigating adult learning of an artificial language and the effects that input frequency (high vs. low token frequency), frequency distribution (skewed vs. balanced), presentation mode (structured vs. scrambled), and first language (English vs. Japanese) have on such learning.…

Incorporating voltage security into the planning, operation and monitoring of restructured electric energy markets

NASA Astrophysics Data System (ADS)

Nair, Nirmal-Kumar

As open access market principles are applied to power systems, significant changes are happening in their planning, operation and control. In the emerging marketplace, systems are operating under higher loading conditions as markets focus greater attention to operating costs than stability and security margins. Since operating stability is a basic requirement for any power system, there is need for newer tools to ensure stability and security margins being strictly enforced in the competitive marketplace. This dissertation investigates issues associated with incorporating voltage security into the unbundled operating environment of electricity markets. It includes addressing voltage security in the monitoring, operational and planning horizons of restructured power system. This dissertation presents a new decomposition procedure to estimate voltage security usage by transactions. The procedure follows physical law and uses an index that can be monitored knowing the state of the system. The expression derived is based on composite market coordination models that have both PoolCo and OpCo transactions, in a shared stressed transmission grid. Our procedure is able to equitably distinguish the impacts of individual transactions on voltage stability, at load buses, in a simple and fast manner. This dissertation formulates a new voltage stability constrained optimal power flow (VSCOPF) using a simple voltage security index. In modern planning, composite power system reliability analysis that encompasses both adequacy and security issues is being developed. We have illustrated the applicability of our VSCOPF into composite reliability analysis. This dissertation also delves into the various applications of voltage security index. Increasingly, FACT devices are being used in restructured markets to mitigate a variety of operational problems. Their control effects on voltage security would be demonstrated using our VSCOPF procedure. Further, this dissertation investigates the application of steady state voltage stability index to detect potential dynamic voltage collapse. Finally, this dissertation examines developments in representation, standardization, communication and exchange of power system data. Power system data is the key input to all analytical engines for system operation, monitoring and control. Data exchange and dissemination could impact voltage security evaluation and therefore needs to be critically examined.

Vortex dynamics studies in supersonic flow

NASA Astrophysics Data System (ADS)

Vergine, Fabrizio

This dissertation covers the study of selected vortex interaction scenarios both in cold and high enthalpy reacting flows. Specifically, the experimental results and the analysis of the flowfields resulting from two selected supersonic vortex interaction modes in a Mach 2.5 cold flow are presented. Additionally, the experiment design, based on vortex dynamics concepts, and the reacting plume survey of two pylon injectors in a Mach 2.4 high enthalpy flow are shown. All the cold flow experiments were conducted in the supersonic wind tunnel of the Aerodynamics Research Center at the University of Texas at Arlington. A strut injector equipped with specified ramp configurations was designed and used to produce the flowfields of interest. The reacting flow experiments were conducted in the the Expansion Tube Facility located in the High Temperature Gasdynamics Laboratory of Stanford University. A detailed description of the supersonic wind tunnel, the instrumentation, the strut injector and the supersonic wake flow downstream is shown as part of the characterization of the facility. As Stereoscopic Particle Image Velocimetry was the principal flow measurement technique used in this work to probe the streamwise vortices shed from ramps mounted on the strut, this dissertation provides a deep overview of the challenges and the application of the aforementioned technique to the survey of vortical flows. Moreover, the dissertation provides the comprehensive analysis of the mean and fluctuating velocity flowfields associated with two distinct vortex dynamics scenarios, as chosen by means of the outcomes of the simulations of a reduced order model developed in the research group. Specifically, the same streamwise vortices (strength, size and Reynolds number) were used experimentally to investigate both a case in which the resulting dynamics evolve in a vortex merging scenario and a case where the merging process is voluntarily avoided in order to focus the analysis on the fundamental differences associated with the amalgamation processes alone. The results from the mean flow highlight major differences between the two cases and will justify the use of the inviscid reduced order model used to predict the main flow physics. The analysis of the turbulence quantities based on concepts borrowed from incompressible turbulence theory explains interesting features of the fluctuating flowfields, suggesting that turbulence associated with the inspected flow conditions is essentially incompressible. Once the interactions among the vortical structures in cold flow were assessed, these vortex dynamics concepts were probed in a reacting environment. The dissertation describes the design phase of two pylon injectors based on the prediction capabilities of the aforementioned model. Then, the results of a set of combustion experiments conducted utilizing hydrogen fuel injected into Mach 2.4, high-enthalpy (2.8˜MJ/kg) air flow are discussed. The results show that, for the heat release levels considered in this study, the morphology of the plume and its evolution is very similar to the results produced by the code, enabling an interpretation of the phenomena based on vortex dynamics considerations. The persistence of the streamwise vortical structures created by the selected ramp configurations is shown together with the effectiveness of the coherent structures in successfully anchoring the flame very close to the injection point. The work shows the possibility of a new approach in the design of injection strategies (i.e., not limited to injection devices) suitable for adoption in scramjet combustors based on the ability to predict, with basic vortex dynamics concepts and a highly reduced computational cost, the main features of flows of technological interest.

Rayleigh-Taylor-instability evolution in colliding-plasma-jet experiments with magnetic and viscous stabilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, Colin Stuart

The Rayleigh-Taylor instability causes mixing in plasmas throughout the universe, from micron-scale plasmas in inertial confinement fusion implosions to parsec-scale supernova remnants. The evolution of this interchange instability in a plasma is influenced by the presence of viscosity and magnetic fields, both of which have the potential to stabilize short-wavelength modes. Very few experimental observations of Rayleigh-Taylor growth in plasmas with stabilizing mechanisms are reported in the literature, and those that are reported are in sub-millimeter scale plasmas that are difficult to diagnose. Experimental observations in well-characterized plasmas are important for validation of computational models used to make design predictionsmore » for inertial confinement fusion efforts. This dissertation presents observations of instability growth during the interaction between a high Mach-number, initially un-magnetized plasma jet and a stagnated, magnetized plasma. A multi-frame fast camera captures Rayleigh-Taylor-instability growth while interferometry, spectroscopy, photodiode, and magnetic probe diagnostics are employed to estimate plasma parameters in the vicinity of the collision. As the instability grows, an evolution to longer mode wavelength is observed. Comparisons of experimental data with idealized magnetohydrodynamic simulations including a physical viscosity model suggest that the observed instability evolution is consistent with both magnetic and viscous stabilization. These data provide the opportunity to benchmark computational models used in astrophysics and fusion research.« less

The comparative importance of books: clinical psychology in the health sciences library.

PubMed Central

Wehmeyer, J M; Wehmeyer, S

1999-01-01

Clinical psychology has received little attention as a subject in health sciences library collections. This study seeks to demonstrate the relative importance of the monographic literature to clinical psychology through the examination of citations in graduate student theses and dissertations at the Fordham Health Sciences Library, Wright State University. Dissertations and theses were sampled randomly; citations were classified by format, counted, and subjected to statistical analysis. Books and book chapters together account for 35% of the citations in clinical psychology dissertations, 25% in nursing theses, and 8% in biomedical sciences theses and dissertations. Analysis of variance indicates that the citations in dissertations and theses in the three areas differ significantly (F = 162.2 with 2 and 253 degrees of freedom, P = 0.0001). Dissertations and theses in biomedical sciences and nursing theses both cite significantly more journals per book than the dissertations in clinical psychology. These results support the hypothesis that users of clinical psychology literature rely more heavily on books than many other users of a health sciences library. Problems with using citation analyses in a single subject to determine a serials to monographs ratio for a health sciences library are pointed out. PMID:10219478

Integrating sequence stratigraphy and rock-physics to interpret seismic amplitudes and predict reservoir quality

NASA Astrophysics Data System (ADS)

Dutta, Tanima

This dissertation focuses on the link between seismic amplitudes and reservoir properties. Prediction of reservoir properties, such as sorting, sand/shale ratio, and cement-volume from seismic amplitudes improves by integrating knowledge from multiple disciplines. The key contribution of this dissertation is to improve the prediction of reservoir properties by integrating sequence stratigraphy and rock physics. Sequence stratigraphy has been successfully used for qualitative interpretation of seismic amplitudes to predict reservoir properties. Rock physics modeling allows quantitative interpretation of seismic amplitudes. However, often there is uncertainty about selecting geologically appropriate rock physics model and its input parameters, away from the wells. In the present dissertation, we exploit the predictive power of sequence stratigraphy to extract the spatial trends of sedimentological parameters that control seismic amplitudes. These spatial trends of sedimentological parameters can serve as valuable constraints in rock physics modeling, especially away from the wells. Consequently, rock physics modeling, integrated with the trends from sequence stratigraphy, become useful for interpreting observed seismic amplitudes away from the wells in terms of underlying sedimentological parameters. We illustrate this methodology using a comprehensive dataset from channelized turbidite systems, deposited in minibasin settings in the offshore Equatorial Guinea, West Africa. First, we present a practical recipe for using closed-form expressions of effective medium models to predict seismic velocities in unconsolidated sandstones. We use an effective medium model that combines perfectly rough and smooth grains (the extended Walton model), and use that model to derive coordination number, porosity, and pressure relations for P and S wave velocities from experimental data. Our recipe provides reasonable fits to other experimental and borehole data, and specifically improves the predictions of shear wave velocities. In addition, we provide empirical relations on normal compaction depth trends of porosity, velocities, and VP/VS ratio for shale and clean sands in shallow, supra-salt sediments in the Gulf of Mexico. Next, we identify probable spatial trends of sand/shale ratio and sorting as predicted by the conventional sequence stratigraphic model in minibasin settings (spill-and-fill model). These spatial trends are evaluated using well data from offshore West Africa, and the same well data are used to calibrate rock physics models (modified soft-sand model) that provide links between P-impedance and quartz/clay ratio, and sorting. The spatial increase in sand/shale ratio and sorting corresponds to an overall increase in P-impedance, and AVO intercept and gradient. The results are used as a guide to interpret sedimentological parameters from seismic attributes, away from the well locations. We present a quantitative link between carbonate cement and seismic attributes by combining stratigraphie cycles and the rock physics model (modified differential effective medium model). The variation in carbonate cement volume in West Africa can be linked with two distinct stratigraphic cycles: the coarsening-upward cycles and the fining-upward cycles. Cemented sandstones associated with these cycles exhibit distinct signatures on P-impedance vs. porosity and AVO intercept vs. gradient crossplots. These observations are important for assessing reservoir properties in the West Africa as well as in other analogous depositional environments. Finally, we investigate the relationship between seismic velocities and time temperature index (TTI) using basin and petroleum system modeling at Rio Muni basin, West Africa. We find that both VP and VS increase exponentially with TTI. The results can be applied to predict TTI, and thereby thermal maturity, from observed velocities.

Behavioral pattern identification for structural health monitoring in complex systems

NASA Astrophysics Data System (ADS)

Gupta, Shalabh

Estimation of structural damage and quantification of structural integrity are critical for safe and reliable operation of human-engineered complex systems, such as electromechanical, thermofluid, and petrochemical systems. Damage due to fatigue crack is one of the most commonly encountered sources of structural degradation in mechanical systems. Early detection of fatigue damage is essential because the resulting structural degradation could potentially cause catastrophic failures, leading to loss of expensive equipment and human life. Therefore, for reliable operation and enhanced availability, it is necessary to develop capabilities for prognosis and estimation of impending failures, such as the onset of wide-spread fatigue crack damage in mechanical structures. This dissertation presents information-based online sensing of fatigue damage using the analytical tools of symbolic time series analysis ( STSA). Anomaly detection using STSA is a pattern recognition method that has been recently developed based upon a fixed-structure, fixed-order Markov chain. The analysis procedure is built upon the principles of Symbolic Dynamics, Information Theory and Statistical Pattern Recognition. The dissertation demonstrates real-time fatigue damage monitoring based on time series data of ultrasonic signals. Statistical pattern changes are measured using STSA to monitor the evolution of fatigue damage. Real-time anomaly detection is presented as a solution to the forward (analysis) problem and the inverse (synthesis) problem. (1) the forward problem - The primary objective of the forward problem is identification of the statistical changes in the time series data of ultrasonic signals due to gradual evolution of fatigue damage. (2) the inverse problem - The objective of the inverse problem is to infer the anomalies from the observed time series data in real time based on the statistical information generated during the forward problem. A computer-controlled special-purpose fatigue test apparatus, equipped with multiple sensing devices (e.g., ultrasonics and optical microscope) for damage analysis, has been used to experimentally validate the STSA method for early detection of anomalous behavior. The sensor information is integrated with a software module consisting of the STSA algorithm for real-time monitoring of fatigue damage. Experiments have been conducted under different loading conditions on specimens constructed from the ductile aluminium alloy 7075 - T6. The dissertation has also investigated the application of the STSA method for early detection of anomalies in other engineering disciplines. Two primary applications include combustion instability in a generic thermal pulse combustor model and whirling phenomenon in a typical misaligned shaft.

[The dissertation as a final product of a specialty in medicine].

PubMed

Ramiro-H, Manuel; Cruz-A, Enrique

2017-01-01

Submitting a written report of a research proyect, also known as dissertation (or thesis), is one of the requirements established by academic institutions for the student to achieve the degree of specialist in medicine. Preparing the dissertation is not only an academic challenge for postgraduate students and professors; it is also a logistical challenge. Highlighting that effort and the dissertation itself will result in a better attention for the beneficiaries of the Instituto Mexicano del Seguro Social.

[Open access to academic scholarship as a public policy resource: a study of the Capes database on Brazilian theses and dissertations].

PubMed

da Silva Rosa, Teresa; Carneiro, Maria José

2010-12-01

Access to scientific knowledge is a valuable resource than can inform and validate positions taken in formulating public policy. But access to this knowledge can be challenging, given the diversity and breadth of available scholarship. Communication between the fields of science and of politics requires the dissemination of scholarship and access to it. We conducted a study using an open-access search tool in order to map existent knowledge on a specific topic: agricultural contributions to the preservation of biodiversity. The present article offers a critical view of access to the information available through the Capes database on Brazilian theses and dissertations.

eBook management in NHS libraries in the North of England: perceptions and practice.

PubMed

Nicholas, Katie

2018-03-01

In this article, Katie Nicholas presents the findings of a very topical piece of research into the use of eBooks in health libraries, which she completed for a Masters dissertation. Katie graduated with an MA in Library and Information Management (Distinction) from Manchester Metropolitan University in July 2017. She would like to acknowledge the support of her supervisor, Rachel Delbridge, in helping her to gain a Distinction in her dissertation. In the article, she points out that the use of eBooks in the NHS is low compared to other sectors and she presents the findings from her research, which help to explain this. She outlines the development of an electronic tool to help library and information staff make sense of the complexity around eBooks and makes further very practical recommendations for practitioners. A. M. © 2018 Health Libraries Group.

Computational and design methods for advanced imaging

NASA Astrophysics Data System (ADS)

Birch, Gabriel C.

This dissertation merges the optical design and computational aspects of imaging systems to create novel devices that solve engineering problems in optical science and attempts to expand the solution space available to the optical designer. This dissertation is divided into two parts: the first discusses a new active illumination depth sensing modality, while the second part discusses a passive illumination system called plenoptic, or lightfield, imaging. The new depth sensing modality introduced in part one is called depth through controlled aberration. This technique illuminates a target with a known, aberrated projected pattern and takes an image using a traditional, unmodified imaging system. Knowing how the added aberration in the projected pattern changes as a function of depth, we are able to quantitatively determine depth of a series of points from the camera. A major advantage this method permits is the ability for illumination and imaging axes to be coincident. Plenoptic cameras capture both spatial and angular data simultaneously. This dissertation present a new set of parameters that permit the design and comparison of plenoptic devices outside the traditionally published plenoptic 1.0 and plenoptic 2.0 configurations. Additionally, a series of engineering advancements are presented, including full system raytraces of raw plenoptic images, Zernike compression techniques of raw image files, and non-uniform lenslet arrays to compensate for plenoptic system aberrations. Finally, a new snapshot imaging spectrometer is proposed based off the plenoptic configuration.

Bilingual/Bicultural Education: Titles and Abstracts of Doctoral Dissertations, Volume II.

ERIC Educational Resources Information Center

California State Univ., Los Angeles. Evaluation, Dissemination and Assessment Center.

This collection of dissertation abstracts on the subjects of bilingual and bicultural education originally published by "Dissertation Abstracts International" contains items in the following areas: bilingual education program management, assessment, language, curriculum, and the affective domain. The section on program management covers scope,…

The Rhetoric of Physics: AN Ethnography of the Research and Writing Processes in a Physics Laboratory.

NASA Astrophysics Data System (ADS)

Graves, Heather Ann Brodie

1992-01-01

This dissertation explores the extent to which rhetoric plays a role in the research and writing processes of physicists. It seeks to join the on-going conversation in the rhetoric of inquiry about the ways in which rhetorical forces shape all knowledge systems. Based on data collected during a six-month ethnography in a thin films laboratory, this study argues that these physicists use rhetoric in all stages of the knowledge creation process. After following the experimental process through all its stages from the inception of an experiment through to publication, this study maps out the types of heuristic devices employed by the physicists as they analyzed, interpreted, and presented their research data in a persuasive scientific article. In light of the insights gained from studying the dynamic interactions between physicists, this dissertation also comments on the theoretical and philosophical debates under discussion in the rhetoric of inquiry and the rhetoric of science. It examines current theories of language (as expressed by rhetoricians, critical theorists, and the physicists in this laboratory) to explore the relationship between reality and language, the role that rhetoric plays in knowledge creation in physics, and the ways in which reality and knowledge may be socially constructed. It concludes that these physicists use rhetorical invention strategies to interpret and present their data. It also argues that scientific knowledge is subject to rhetorical forces because it deals with contingent affairs--phenomena about which scientists advance propositions which appear to be true but about which there is no way to gain absolute certainty or truth. Finally, it concludes that rhetoric both is and is not epistemic in the physics research studied here, and it argues that instead of asking "Is rhetoric epistemic?" perhaps we might shift our attention to inquiring "When is rhetoric epistemic?".

A Theory of Direct Discourse: Its Semantics and Pragmatics

ERIC Educational Resources Information Center

Matsusaka, Youichi

2013-01-01

The dissertation presents a new account of how direct discourse works in natural language. After presenting preliminary discussions of the views of quotation given by Tarski, Quine, and Davidson in Chapter 1, Chapter 2 is devoted to historical investigations into Frege's theory of quotation and direct discourse. Although Frege's theory is often…

Three Pedagogical Approaches to Introductory Physics Labs and Their Effects on Student Learning Outcomes

ERIC Educational Resources Information Center

Chambers, Timothy

2014-01-01

This dissertation presents the results of an experiment that measured the learning outcomes associated with three different pedagogical approaches to introductory physics labs. These three pedagogical approaches presented students with the same apparatus and covered the same physics content, but used different lab manuals to guide students through…

Understanding and Creating Accessible Touch Screen Interactions for Blind People

ERIC Educational Resources Information Center

Kane, Shaun K.

2011-01-01

Using touch screens presents a number of usability and accessibility challenges for blind people. Most touch screen-based user interfaces are optimized for visual interaction, and are therefore difficult or impossible to use without vision. This dissertation presents an approach to redesigning gesture-based user interfaces to enable blind people…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cornejo, Juan Carlos

The Standard Model has been a theory with the greatest success in describing the fundamental interactions of particles. As of the writing of this dissertation, the Standard Model has not been shown to make a false prediction. However, the limitations of the Standard Model have long been suspected by its lack of a description of gravity, nor dark matter. Its largest challenge to date, has been the observation of neutrino oscillations, and the implication that they may not be massless, as required by the Standard Model. The growing consensus is that the Standard Model is simply a lower energy effectivemore » field theory, and that new physics lies at much higher energies. The Q weak Experiment is testing the Electroweak theory of the Standard Model by making a precise determination of the weak charge of the proton (Q p w). Any signs of "new physics" will appear as a deviation to the Standard Model prediction. The weak charge is determined via a precise measurement of the parity-violating asymmetry of the electron-proton interaction via elastic scattering of a longitudinally polarized electron beam of an un-polarized proton target. The experiment required that the electron beam polarization be measured to an absolute uncertainty of 1%. At this level the electron beam polarization was projected to contribute the single largest experimental uncertainty to the parity-violating asymmetry measurement. This dissertation will detail the use of Compton scattering to determine the electron beam polarization via the detection of the scattered photon. I will conclude the remainder of the dissertation with an independent analysis of the blinded Q weak.« less

Bayesian superresolution

NASA Astrophysics Data System (ADS)

Isakson, Steve Wesley

2001-12-01

Well-known principles of physics explain why resolution restrictions occur in images produced by optical diffraction-limited systems. The limitations involved are present in all diffraction-limited imaging systems, including acoustical and microwave. In most circumstances, however, prior knowledge about the object and the imaging system can lead to resolution improvements. In this dissertation I outline a method to incorporate prior information into the process of reconstructing images to superresolve the object beyond the above limitations. This dissertation research develops the details of this methodology. The approach can provide the most-probable global solution employing a finite number of steps in both far-field and near-field images. In addition, in order to overcome the effects of noise present in any imaging system, this technique provides a weighted image that quantifies the likelihood of various imaging solutions. By utilizing Bayesian probability, the procedure is capable of incorporating prior information about both the object and the noise to overcome the resolution limitation present in many imaging systems. Finally I will present an imaging system capable of detecting the evanescent waves missing from far-field systems, thus improving the resolution further.

Experimental and theoretical identification of a four- acoustic-inputs/two-vibration-outputs hearing system

NASA Astrophysics Data System (ADS)

Balaji, P. A.

1999-07-01

A cricket's ear is a directional acoustic sensor. It has a remarkable level of sensitivity to the direction of sound propagation in a narrow frequency bandwidth of 4-5 KHz. Because of its complexity, the directional sensitivity has long intrigued researchers. The cricket's ear is a four-acoustic-inputs/two-vibration-outputs system. In this dissertation, this system is examined in depth, both experimentally and theoretically, with a primary goal to understand the mechanics involved in directional hearing. Experimental identification of the system is done by using random signal processing techniques. Theoretical identification of the system is accomplished by analyzing sound transmission through complex trachea of the ear. Finally, a description of how the cricket achieves directional hearing sensitivity is proposed. The fundamental principle involved in directional heating of the cricket has been utilized to design a device to obtain a directional signal from non- directional inputs.

Sparse and redundant representations for inverse problems and recognition

NASA Astrophysics Data System (ADS)

Patel, Vishal M.

Sparse and redundant representation of data enables the description of signals as linear combinations of a few atoms from a dictionary. In this dissertation, we study applications of sparse and redundant representations in inverse problems and object recognition. Furthermore, we propose two novel imaging modalities based on the recently introduced theory of Compressed Sensing (CS). This dissertation consists of four major parts. In the first part of the dissertation, we study a new type of deconvolution algorithm that is based on estimating the image from a shearlet decomposition. Shearlets provide a multi-directional and multi-scale decomposition that has been mathematically shown to represent distributed discontinuities such as edges better than traditional wavelets. We develop a deconvolution algorithm that allows for the approximation inversion operator to be controlled on a multi-scale and multi-directional basis. Furthermore, we develop a method for the automatic determination of the threshold values for the noise shrinkage for each scale and direction without explicit knowledge of the noise variance using a generalized cross validation method. In the second part of the dissertation, we study a reconstruction method that recovers highly undersampled images assumed to have a sparse representation in a gradient domain by using partial measurement samples that are collected in the Fourier domain. Our method makes use of a robust generalized Poisson solver that greatly aids in achieving a significantly improved performance over similar proposed methods. We will demonstrate by experiments that this new technique is more flexible to work with either random or restricted sampling scenarios better than its competitors. In the third part of the dissertation, we introduce a novel Synthetic Aperture Radar (SAR) imaging modality which can provide a high resolution map of the spatial distribution of targets and terrain using a significantly reduced number of needed transmitted and/or received electromagnetic waveforms. We demonstrate that this new imaging scheme, requires no new hardware components and allows the aperture to be compressed. Also, it presents many new applications and advantages which include strong resistance to countermesasures and interception, imaging much wider swaths and reduced on-board storage requirements. The last part of the dissertation deals with object recognition based on learning dictionaries for simultaneous sparse signal approximations and feature extraction. A dictionary is learned for each object class based on given training examples which minimize the representation error with a sparseness constraint. A novel test image is then projected onto the span of the atoms in each learned dictionary. The residual vectors along with the coefficients are then used for recognition. Applications to illumination robust face recognition and automatic target recognition are presented.

Reviewing the Review: An Assessment of Dissertation Reviewer Feedback Quality

ERIC Educational Resources Information Center

Lehan, Tara; Hussey, Heather; Mika, Eva

2016-01-01

Throughout the dissertation process, the chair and committee members provide feedback regarding quality to help the doctoral candidate to produce the highest-quality document and become an independent scholar. Nevertheless, results of previous research suggest that overall dissertation quality generally is poor. Because much of the feedback about…

The UK Postgraduate Masters Dissertation: An "Elusive Chameleon"?

ERIC Educational Resources Information Center

Pilcher, Nick

2011-01-01

Many studies into the process of producing and supervising dissertations exist, yet little research into the "product" of the Masters dissertation, or into how Masters supervision changes over time exist. Drawing on 62 semi-structured interviews with 31 Maths and Computer Science supervisors over a two-year period, this paper explores…

Electronic Theses and Dissertations: Promoting "Hidden" Research

ERIC Educational Resources Information Center

Copeland, Susan

2008-01-01

Since the mid 1990s an increasing number of higher education institutions and organisations have been encouraging the production and submission of theses and dissertations in electronic format. Where access to electronic theses and dissertations is available via the Internet, usage figures indicate that this is a much consulted resource. However,…

Lessons Learned for Successful Dissertation Completion from Social Work Doctoral Graduates

ERIC Educational Resources Information Center

Davis, Ashley; Wladkowski, Stephanie P.; Mirick, Rebecca G.

2017-01-01

A dissertation demonstrates a doctoral candidate's knowledge of a content area, mastery of research methodology, and readiness for future scholarship. Doctoral candidates, social work programs, and the profession as a whole are invested in ensuring that candidates successfully complete dissertations and enter academic, research, and leadership…

Networks at Their Limits: Software, Similarity, and Continuity in Vietnam

ERIC Educational Resources Information Center

Nguyen, Lilly Uyen

2013-01-01

This dissertation explores the social worlds of pirated software discs and free/open source software in Vietnam to describe the practices of copying, evangelizing, and translation. This dissertation also reveals the cultural logics of similarity and continuity that sustain these social worlds. Taken together, this dissertation argues that the…

Gatecrashing the Oasis? A Joint Doctoral Dissertation Play

ERIC Educational Resources Information Center

Gale, Ken; Speedy, Jane; Wyatt, Jonathan

2010-01-01

This article explores the institutional and individual struggles surrounding the submission for examination of a jointly authored doctoral dissertation at a U.K. civic university. Two of the article's authors (Gale and Wyatt) were the dissertation's authors, and Speedy, the article's third author, is their supervisor. Joint doctoral dissertations…

Economics of Corruption in Doctoral Education: The Dissertations Market

ERIC Educational Resources Information Center

Osipian, Ararat L.

2012-01-01

This paper addresses the issue of "dissertations for sale" in Russia. The tasks of this anthropological study include establishing the problem of corruption in doctoral education, identification of the dissertations suppliers, study of the specific services they offer, analysis of their prices on different services, and generalizations…

Using a nursing theory or a model in nursing PhD dissertations: a qualitative study from Turkey.

PubMed

Mete, Samiye; Gokçe İsbir, Gozde

2015-04-01

The aim of this study was to reveal experiences of nursing students and their advisors using theories and models in their PhD dissertations. The study adopted a descriptive qualitative approach. This study was performed with 10 PhD candidates and their five advisors from nursing faculty. The results of the study were categorized into four. These are reasons for using a theory/model in a PhD dissertation, reasons for preferring a given model, causes of difficulties in using models in PhD dissertations, and facilitating factors of using theories and models in PhD of dissertations. It was also reported to contribute to the methodology of research and professional development of the students and advisors. © 2014 NANDA International, Inc.

The Dissertation House Model: Doctoral Student Experiences Coping and Writing in a Shared Knowledge Community

PubMed Central

Carter-Veale, Wendy Y.; Tull, Renetta G.; Rutledge, Janet C.; Joseph, Lenisa N.

2016-01-01

The problem of PhD attrition, especially at the dissertation-writing stage, is not solely related to mentoring, departments, or disciplines; it is a problem that affects the entire institution. As such, solutions require collaborative efforts for student success. Building on Yeatman’s master–apprentice model, which assumes mastering disciplinary writing in singular advisor–student contexts, and Burnett’s collaborative cohort model, which introduced doctoral dissertation supervision in a collaborative-learning environment with several faculty mentors in a single discipline, the Dissertation House model (DHM) introduces a model of doctoral dissertation supervision that involves multiple mentors across several disciplines. On the basis of more than 200 students’ reflections, we find that challenges in completing the dissertation extend beyond departmental and disciplinary boundaries. The DHM’s multidisciplinary approach preserves the traditional master–apprentice relationship between faculty and students within academic departments while providing an additional support mechanism through interdisciplinary collaborative cohorts. Using Thoits’s coping assistance theory and data from DH students over a 10-year period, the DHM incorporates Hoadley’s concept of knowledge communities to establish a successful dissertation-writing intervention for graduate students across doctoral programs. Using propensity score analysis, we provide in this study an empirical assessment of the benefits and efficacy of the DHM. PMID:27521236

The German medical dissertation--time to change?

PubMed

Diez, C; Arkenau, C; Meyer-Wentrup, F

2000-08-01

German medical students must conduct a research project and write a dissertation in order to receive the title "Doctor." However, the dissertation is not required to graduate, enter a residency, or practice medicine. About 90% of practicing physicians hold the title "Doctor"; a career in academic medicine almost always requires it. Although no convincing evidence supports the usefulness of the dissertation, many regard its completion as important to maintaining a high level of scientific competence and patient care. In recent years, the number of successfully completed dissertations has declined. Lack of time during medical school, the perceived irrelevance of the dissertation to medical practice, and the poor design of many projects may be at least part of the problem. There is also increasing evidence that conducting research frequently delays graduation and may affect clinical skills because students working on projects attend fewer classes, ward rounds, and clinical tutorials and do not spent sufficient time preparing for examinations. The scientific value of students' research has also been criticized; critics point out that students do not have enough time or experience to critically analyze methods and data, and they often are not properly supervised. European unification will probably lead to standardized requirements for medical education and research. The authors hope this will eliminate the dissertation requirement in Germany.

Stiffness characteristics of airfoils under pulse loading

NASA Astrophysics Data System (ADS)

Turner, Kevin Eugene

The turbomachinery industry continually struggles with the adverse effects of contact rubs between airfoils and casings. The key parameter controlling the severity of a given rub event is the contact load produced when the airfoil tips incur into the casing. These highly non-linear and transient forces are difficult to calculate and their effects on the static and rotating components are not well understood. To help provide this insight, experimental and analytical capabilities have been established and exercised through an alliance between GE Aviation and The Ohio State University Gas Turbine Laboratory. One of the early findings of the program is the influence of blade flexibility on the physics of rub events. The core focus of the work presented in this dissertation is to quantify the influence of airfoil flexibility through a novel modeling approach that is based on the relationship between applied force duration and maximum tip deflection. This relationship is initially established using a series of forward, non-linear and transient analyses in which simulated impulse rub loads are applied. This procedure, although effective, is highly inefficient and costly to conduct by requiring numerous explicit simulations. To alleviate this issue, a simplified model, named the pulse magnification model, is developed that only requires a modal analysis and a static analyses to fully describe how the airfoil stiffness changes with respect to load duration. Results from the pulse magnification model are compared to results from the full transient simulation method and to experimental results, providing sound verification for the use of the modeling approach. Furthermore, a unique and highly efficient method to model airfoil geometries was developed and is outlined in this dissertation. This method produces quality Finite Element airfoil definitions directly from a fully parameterized mathematical model. The effectiveness of this approach is demonstrated by comparing modal properties of the simulated geometries to modal properties of various current airfoil designs. Finally, this modeling approach was used in conjunction with the pulse magnification model to study the effects of various airfoil geometric features on the stiffness of the blade under impulsive loading.

Plasma Wakefield Acceleration of an Intense Positron Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blue, B

2004-04-21

The Plasma Wakefield Accelerator (PWFA) is an advanced accelerator concept which possess a high acceleration gradient and a long interaction length for accelerating both electrons and positrons. Although electron beam-plasma interactions have been extensively studied in connection with the PWFA, very little work has been done with respect to positron beam-plasma interactions. This dissertation addresses three issues relating to a positron beam driven plasma wakefield accelerator. These issues are (a) the suitability of employing a positron drive bunch to excite a wake; (b) the transverse stability of the drive bunch; and (c) the acceleration of positrons by the plasma wakemore » that is driven by a positron bunch. These three issues are explored first through computer simulations and then through experiments. First, a theory is developed on the impulse response of plasma to a short drive beam which is valid for small perturbations to the plasma density. This is followed up with several particle-in-cell (PIC) simulations which study the experimental parameter (bunch length, charge, radius, and plasma density) range. Next, the experimental setup is described with an emphasis on the equipment used to measure the longitudinal energy variations of the positron beam. Then, the transverse dynamics of a positron beam in a plasma are described. Special attention is given to the way focusing, defocusing, and a tilted beam would appear to be energy variations as viewed on our diagnostics. Finally, the energy dynamics imparted on a 730 {micro}m long, 40 {micro}m radius, 28.5 GeV positron beam with 1.2 x 10{sup 10} particles in a 1.4 meter long 0-2 x 10{sup 14} e{sup -}/cm{sup 3} plasma is described. First the energy loss was measured as a function of plasma density and the measurements are compared to theory. Then, an energy gain of 79 {+-} 15 MeV is shown. This is the first demonstration of energy gain of a positron beam in a plasma and it is in good agreement with the predictions made by the 3-D PIC code. The work presented in this dissertation will show that plasma wakefield accelerators are an attractive technology for future particle accelerators.« less

Fiber-optic beam control systems using microelectromechanical systems

NASA Astrophysics Data System (ADS)

Sumriddetchkajorn, Sarun

This dissertation, for the first time, proposes, studies, and experimentally demonstrated novel fiber-optic beam control systems based on the use of microelectromechanical system (MEMS) technology in which the miniaturized versions of mechanical systems can be obtained. Beam control modules include optical add/drop filters, optical switches, variable photonic delay lines (VPDLs), and variable optical attenuators (VOAs). The optical add/drop filter functions as a multiwavelength optical switch that offers the ability to drop and add a certain number of desired wavelengths at an intermediate location where access to all the propagating optical channels is not required between transmission terminals. The VOA can also be used in networks where stocking and tracking of fixed attenuators is difficult. Other specific applications of the VOA are optical gain equalization and polarization dependent loss and gain compensation required in high data-rate wavelength division multiplexed (WDM) lightwave systems. A VPDL can be used to adjust timing amongst multiwavelength optical signals in order to reduce timing jitter and burst traffic in photonic packet switching and parallel signal processing systems. In this dissertation, a small tilt micromirror device is proposed for the implementation of all fiber-optic beam control modules. In particular, the macro-pixel approach where several micromirrors are used to manipulate the desired optical beam is introduced to realize high speed and fault tolerant beam control modules. To eliminate the need of careful optical alignment, an all fiber-connectorized multiwavelength optical switch structure is presented and experimentally demonstrated by using a fiber-loop mirror concept with polarization control. In addition, liquid crystal (LC) devices are studied and are used to implement a compact retro- reflective 2 x 2 fiber-optic switch. Compared to MEMS- based mirror technology, the LC technology is more sensitive to temperature, thereby inappropriate to deploy in a harsh environment. With the benefit provided by WDM systems, wavelength sensitive fiber-optic beam controllers are proposed, offering wavelength sensitive time delay and amplitude controls that can be applied in several applications ranging from optical communications to high speed parallel signal processing. (Abstract shortened by UMI.)

Laser-Material Interaction of Powerful Ultrashort Laser Pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komashko, A

2003-01-06

Laser-material interaction of powerful (up to a terawatt) ultrashort (several picoseconds or shorter) laser pulses and laser-induced effects were investigated theoretically in this dissertation. Since the ultrashort laser pulse (USLP) duration time is much smaller than the characteristic time of the hydrodynamic expansion and thermal diffusion, the interaction occurs at a solid-like material density with most of the light energy absorbed in a thin surface layer. Powerful USLP creates hot, high-pressure plasma, which is quickly ejected without significant energy diffusion into the bulk of the material, Thus collateral damage is reduced. These and other features make USLPs attractive for amore » variety of applications. The purpose of this dissertation was development of the physical models and numerical tools for improvement of our understanding of the process and as an aid in optimization of the USLP applications. The study is concentrated on two types of materials - simple metals (materials like aluminum or copper) and wide-bandgap dielectrics (fused silica, water). First, key physical phenomena of the ultrashort light interaction with metals and the models needed to describe it are presented. Then, employing one-dimensional plasma hydrodynamics code enhanced with models for laser energy deposition and material properties at low and moderate temperatures, light absorption was self-consistently simulated as a function of laser wavelength, pulse energy and length, angle of incidence and polarization. Next, material response on time scales much longer than the pulse duration was studied using the hydrocode and analytical models. These studies include examination of evolution of the pressure pulses, effects of the shock waves, material ablation and removal and three-dimensional dynamics of the ablation plume. Investigation of the interaction with wide-bandgap dielectrics was stimulated by the experimental studies of the USLP surface ablation of water (water is a model of biological tissue) and laser-induced pressure waves. Simulations on the basis of the nonlinear ionization equation were used to examine effects of the laser created surface plasma on light absorption, reflection and transmission. Laser pulse energy conversion efficiency into pressure waves was studied experimentally and theoretically.« less

Experimental studies of fundamental aspects of Auger emission process in Cu(100) and Ag(100)

NASA Astrophysics Data System (ADS)

Joglekar, Prasad Vivek

Auger spectra at the low energies are accompanied by large contributions unrelated to the Auger transition. The Auger unrelated contributions can obscure the Auger peak and affect the quantitative analysis of the materials under investigation. In this dissertation we present a methodology to measure experimentally the Auger unrelated contributions and eliminate it from the Auger spectrum for obtaining an Auger spectrum inherent to the Auger transition. We used Auger Photoelectron Coincidence Spectroscopy (APECS) to obtain the Auger spectrum. APECS measures the Auger spectrum in coincidence with the core energy level and thus discriminating the contributions arising from secondary electrons and electrons arising from the non-Auger transition. Although APECS removes most of the Auger unrelated contributions, it cannot distinguish the contribution which is measured in coincidence with the inelastically scattered valence band electrons emitted at the core energy. To measure this inelastically scattered valence band contribution we did a series of measurements on Ag(100) to study NVV Auger spectrum in coincidence with 4p energy level and Cu(100) to study MVV Auger spectrum in coincidence with 3p energy level. The coincidence detection of the core and Auger-valence electrons was achieved by the two cylindrical mirror analyzers (CMAs). One CMA was fixed over a range of energies in between VB and core energy level while other CMA scanned corresponding low energy electrons from 0 to70eV. The spectrums measured were fit to a parameterized function which was extrapolated to get an estimate of inelastically scattered valence band electrons. The estimated contribution was subtracted for the Ag and Cu APECS spectrum to obtain a spectrum solely due to Auger transition with inelastically scattered Auger electron and multi Auger decay contributions associated with the transition. In the latter part of this dissertation, we propose a theoretical model based on the spectral intensity contributions arising from elastically scattered electrons from the atomic layers and relate it with the data obtained from our experiments to estimate the Auger related contribution.

Preverbal Particles in Pingelapese: A Language of Micronesia

ERIC Educational Resources Information Center

Hattori, Ryoko

2012-01-01

This dissertation presents a synchronic and diachronic study of Pingelapese pronouns and auxiliary verbs--"ae", "e", "aen", and "en". Synchronically, Pingelapese employs subject pronominal clitics, not subject agreement markers, unlike Proto-Micronesian and many other contemporary Micronesian languages.…

Theoretical Calculations for Electron Impact Ionization of Atoms and Molecules

NASA Astrophysics Data System (ADS)

Amami, Sadek Mohamed Fituri

In the last twenty years, significant progress has been made for the theoretical treatment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for ionization of hydrogen and helium. However, agreement between experiment and theory is not nearly as good for ionization of larger atoms and molecules. In the first part of this dissertation, different theoretical approaches will be employed to study the triply differential cross section (TDCS) for low and intermediate energy electron-impact ionization of Neon and Argon for different orbital states. There is a very recent interest in studying ionization of Laser aligned atoms in order to get a better understanding about electron impact ionization of molecules. In the next part of this dissertation, results will be presented for electron-impact ionization of three laser aligned atoms, Mg, Ca, and Na. The comparison between the theory and experiment showed that our three body distorted wave (3DW) model gave excellent agreement with experiment in the scattering plane but very poor agreement perpendicular to the scattering plane. An explanation for this poor agreement out of the scattering plane has been provided by comparing our theoretical results with those of the time depended close coupling (TDCC) model and this explanation is also provided in this dissertation. Recently, significant attention has been directed towards obtaining a better under-standing of electron-impact ionization of molecules which are significantly more challenging than atoms. In the last part of this dissertation, results will be presented for electron-impact ionization of three different molecules (N2 , H2O, and CH4) which have been studied comprehensively using different theoretical approximations for different types of geometries. The published papers in section two contain a detailed analysis and discussion for each of these topics.

The Path to Graduation: A Model Interactive Web Site Design Supporting Doctoral Students

ERIC Educational Resources Information Center

Simmons-Johnson, Nicole

2012-01-01

Objective. This 2-phase mixed method study assessed 2nd-year doctoral students' and dissertation students' perceptions of the current Graduate School of Education dissertation support Web site, with implications for designing a model dissertation support Web site. Methods. Phase 1 collected quantitative and qualitative data through an…

LIS Dissertation Titles and Abstracts (1930-2009): Where Have All the Librar* Gone?

ERIC Educational Resources Information Center

Finlay, Craig S.; Sugimoto, Cassidy R.; Li, Daifeng; Russell, Terrell G.

2012-01-01

This article examines the topicality of Library and Information Science (LIS) dissertations written between 1930 and 2009 at schools with American Library Association (ALA)--accredited university programs in North America. Dissertation titles and abstracts were examined for the presence of library-related keywords drawn from the core curricula of…

An Analysis of Professional Practice Ed.D. Dissertations in Educational Technology

ERIC Educational Resources Information Center

Dawson, Kara; Kumar, Swapna

2014-01-01

The University of Florida offers an online professional practice Ed.D. focused on Educational Technology. Twenty-three students have completed professional practice dissertations and graduated since the program's inception in 2008. The purpose of this article is to share what these dissertations have looked like and to begin a dialogue about…

Examining CPED Cohort Dissertations: A Window into the Learning of EdD Students

ERIC Educational Resources Information Center

Chan, Elaine; Heaton, Ruth M.; Swidler, Stephen A.; Wunder, Susan

2013-01-01

Through analyses of three dissertations completed by graduates of our Carnegie Project for the Education Doctorate-influenced program, this article offers insights into both the doctoral students' inquiries into their problems of practice and their faculty advisors' roles and expectations for them. Studying student dissertations provided the…

Evaluability Assessment Thesis and Dissertation Studies in Graduate Professional Degree Programs

ERIC Educational Resources Information Center

Walser, Tamara M.; Trevisan, Michael S.

2016-01-01

Evaluability assessment (EA) has potential as a design option for thesis and dissertation studies, serving as a practical training experience for both technical and nontechnical evaluation skills. Based on a content review of a sample of EA theses and dissertations from graduate professional degree programs, the authors of this article found that…

The Student Affair Organizational Dissertation: A Bounded Qualitative Meta-Study

ERIC Educational Resources Information Center

Banning, James H.; Kuk, Linda

2009-01-01

The purpose of this study was to examine dissertations over the past five years that focused on student affairs organizational issues. A bounded qualitative meta-study was used and the methods, theories, and findings of the dissertations were examined. A variety of research methods were used including quantitative, qualitative and mixed designs.…

The PhD Dissertation Defense in Canada: An Institutional Policy Perspective

ERIC Educational Resources Information Center

Chen, Shuhua

2008-01-01

Drawing upon publicly accessible information on the websites of ten Canadian research universities, this paper aims to shed some light on the assumed variation of institutional policies regarding the PhD dissertation defense in Canada. It discusses "How are the institutional policies on the doctoral dissertation defense different across…

(Re)Reenvisioning the Dissertation in English Studies.

ERIC Educational Resources Information Center

Olson, Gary A.; Drew, Julie

1998-01-01

Contends that the academy has forgotten the origin of the dissertation and has turned it from a substantive contribution of scholarship to an instrument of evaluation. Argues that continuing to treat the dissertation in this way maintains an unequal power hierarchy of "masters" and initiates--it should be seen as the first serious scholarly…

An Examination of the Quality of Leadership Studies Dissertations and Characteristics of Successful Doctoral Graduates

ERIC Educational Resources Information Center

Richardson, Paul Truman

2013-01-01

This qualitative study sought to characterize what constitutes quality in leadership studies dissertations. The individual opinions of twenty doctoral faculty members were solicited to identify characteristics of leadership studies dissertation quality. The study further sought to identify possible areas of agreement among participants about the…

Defining the Problem of Practice Dissertation: Where's the Practice, What's the Problem?

ERIC Educational Resources Information Center

Belzer, Alisa; Ryan, Sharon

2013-01-01

This article describes the evolution of the conceptualization of the "problem of practice" dissertation in the new EdD Program at the Graduate School of Education at Rutgers, the State University of New Jersey. Our definition and conceptualization of the professional practice dissertation is grounded in a review of relevant literature…

How Does Completing a Dissertation Transform Undergraduate Students' Understandings of Disciplinary Knowledge?

ERIC Educational Resources Information Center

Ashwin, Paul; Abbas, Andrea; McLean, Monica

2017-01-01

Dissertations are positioned as the capstone of an undergraduate degree, bringing together what students have previously learned from their programmes through a piece of independent research. However, there is limited research into the ways in which engaging in a dissertation has an impact on students' understandings of disciplinary knowledge. In…

Shall We Dance? The Importance of Staff-Student Relationships to Undergraduate Dissertation Preparation

ERIC Educational Resources Information Center

Derounian, James

2011-01-01

This article evaluates the factors that comprise the staff-student relationship as it relates to undergraduate dissertation preparation. By utilizing secondary and primary material the article pinpoints the emotionally charged backdrop to the dissertation--for both students and staff. The research points to the combined intellectual and…

Applications of Agent Based Approaches in Business (A Three Essay Dissertation)

ERIC Educational Resources Information Center

Prawesh, Shankar

2013-01-01

The goal of this dissertation is to investigate the enabling role that agent based simulation plays in business and policy. The aforementioned issue has been addressed in this dissertation through three distinct, but related essays. The first essay is a literature review of different research applications of agent based simulation in various…

34 CFR 662.20 - How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Abroad Fellow selected? 662.20 Section 662.20 Education Regulations of the Offices of the Department of... DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM Selection of Fellows § 662.20 How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected? (a) The Secretary considers applications for fellowships under...

34 CFR 662.20 - How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Abroad Fellow selected? 662.20 Section 662.20 Education Regulations of the Offices of the Department of... DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM Selection of Fellows § 662.20 How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected? (a) The Secretary considers applications for fellowships under...

34 CFR 662.20 - How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Abroad Fellow selected? 662.20 Section 662.20 Education Regulations of the Offices of the Department of... DISSERTATION RESEARCH ABROAD FELLOWSHIP PROGRAM Selection of Fellows § 662.20 How is a Fulbright-Hays Doctoral Dissertation Research Abroad Fellow selected? (a) The Secretary considers applications for fellowships under...

Enhancing Student Competency and Employability in International Business through Master's Dissertations

ERIC Educational Resources Information Center

Sinkovics, Rudolf R.; Richardson, Christopher; Lew, Yong Kyu

2015-01-01

A core component of International Business (IB) postgraduate programs around the world is the master's dissertation, which requires students to produce a written document, typically around 20,000 words in length, based on empirical research. While the dissertation is given considerable importance in such programs, often accounting for more than a…

Astrophysical blast wave data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riley, Nathan; Geissel, Matthias; Lewis, Sean M

2015-03-01

The data described in this document consist of image files of shadowgraphs of astrophysically relevant laser driven blast waves. Supporting files include Mathematica notebooks containing design calculations, tabulated experimental data and notes, and relevant publications from the open research literature. The data was obtained on the Z-Beamlet laser from July to September 2014. Selected images and calculations will be published as part of a PhD dissertation and in associated publications in the open research literature, with Sandia credited as appropriate. The authors are not aware of any restrictions that could affect the release of the data.

High speed fiber optics local area networks: Design and implementation

NASA Technical Reports Server (NTRS)

Tobagi, Fouad A.

1988-01-01

The design of high speed local area networks (HSLAN) for communication among distributed devices requires solving problems in three areas: (1) the network medium and its topology; (2) the medium access control; and (3) the network interface. Considerable progress has been made in all areas. Accomplishments are divided into two groups according to their theoretical or experimental nature. A brief summary is given in Section 2, including references to papers which appeared in the literature, as well as to Ph.D. dissertations and technical reports published at Stanford University.

An Experimental Study of an Ultra-Mobile Vehicle for Off-Road Transportation. Appendix 2. Dissertation. Kinematic Optimal Design of a Six-Legged Walking Machine.

DTIC Science & Technology

1985-05-01

6° . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . 36 - C Lb = (n-1) P (3.1) Definition 10: A gait matrix ...Research Projects Agency under Contracts MDA 903-81- C -0138 and MDA 903-82-K-00S8. iv °.a. . a a . -- ..... a * ... , VITA August 12, 1951 .. . Born -Taipe...PATTERN APPENDIX C . STRESS ANALYSIS OF FOUR-BAR LEG BY FINITE .5’ .5 EEETBLETOD ONS . con. ..in ...ue .d9 Chapte Page xiv .. 5 ----A i I I ’I I i

Designing instruction to support mechanical reasoning: Three alternatives in the simple machines learning environment

NASA Astrophysics Data System (ADS)

McKenna, Ann Frances

2001-07-01

Creating a classroom environment that fosters a productive learning experience and engages students in the learning process is a complex endeavor. A classroom environment is dynamic and requires a unique synergy among students, teacher, classroom artifacts and events to achieve robust understanding and knowledge integration. This dissertation addresses this complex issue by developing, implementing, and investigating the simple machines learning environment (SIMALE) to support students' mechanical reasoning and understanding. SIMALE was designed to support reflection, collaborative learning, and to engage students in generative learning through multiple representations of concepts and successive experimentation and design activities. Two key components of SIMALE are an original web-based software tool and hands-on Lego activities. A research study consisting of three treatment groups was created to investigate the benefits of hands-on and web-based computer activities on students' analytic problem solving ability, drawing/modeling ability, and conceptual understanding. The study was conducted with two populations of students that represent a diverse group with respect to gender, ethnicity, academic achievement and social/economic status. One population of students in this dissertation study participated from the Mathematics, Engineering, and Science Achievement (MESA) program that serves minorities and under-represented groups in science and mathematics. The second group was recruited from the Academic Talent Development Program (ATDP) that is an academically competitive outreach program offered through the University of California at Berkeley. Results from this dissertation show success of the SIMALE along several dimensions. First, students in both populations achieved significant gains in analytic problem solving ability, drawing/modeling ability, and conceptual understanding. Second, significant differences that were found on pre-test measures were eliminated on post-test measures. Specifically, female students scored significantly lower than males on the overall pre-tests but scored as well as males on the same post-test measures. MESA students also scored significantly lower than ATDP students on pre-test measures but both populations scored equally well on the post-tests. This dissertation has therefore shown the SIMALE to support a collaborative, reflective, and generative learning environment. Furthermore, the SIMALE clearly contributes to students' mechanical reasoning and understanding of simple machines concepts for a diverse population of students.

Incorporating Auditory Models in Speech/Audio Applications

NASA Astrophysics Data System (ADS)

Krishnamoorthi, Harish

2011-12-01

Following the success in incorporating perceptual models in audio coding algorithms, their application in other speech/audio processing systems is expanding. In general, all perceptual speech/audio processing algorithms involve minimization of an objective function that directly/indirectly incorporates properties of human perception. This dissertation primarily investigates the problems associated with directly embedding an auditory model in the objective function formulation and proposes possible solutions to overcome high complexity issues for use in real-time speech/audio algorithms. Specific problems addressed in this dissertation include: 1) the development of approximate but computationally efficient auditory model implementations that are consistent with the principles of psychoacoustics, 2) the development of a mapping scheme that allows synthesizing a time/frequency domain representation from its equivalent auditory model output. The first problem is aimed at addressing the high computational complexity involved in solving perceptual objective functions that require repeated application of auditory model for evaluation of different candidate solutions. In this dissertation, a frequency pruning and a detector pruning algorithm is developed that efficiently implements the various auditory model stages. The performance of the pruned model is compared to that of the original auditory model for different types of test signals in the SQAM database. Experimental results indicate only a 4-7% relative error in loudness while attaining up to 80-90 % reduction in computational complexity. Similarly, a hybrid algorithm is developed specifically for use with sinusoidal signals and employs the proposed auditory pattern combining technique together with a look-up table to store representative auditory patterns. The second problem obtains an estimate of the auditory representation that minimizes a perceptual objective function and transforms the auditory pattern back to its equivalent time/frequency representation. This avoids the repeated application of auditory model stages to test different candidate time/frequency vectors in minimizing perceptual objective functions. In this dissertation, a constrained mapping scheme is developed by linearizing certain auditory model stages that ensures obtaining a time/frequency mapping corresponding to the estimated auditory representation. This paradigm was successfully incorporated in a perceptual speech enhancement algorithm and a sinusoidal component selection task.

Novel Material Integration for Reliable and Energy-Efficient NEM Relay Technology

NASA Astrophysics Data System (ADS)

Chen, I.-Ru

Energy-efficient switching devices have become ever more important with the emergence of ubiquitous computing. NEM relays are promising to complement CMOS transistors as circuit building blocks for future ultra-low-power information processing, and as such have recently attracted significant attention from the semiconductor industry and researchers. Relay technology potentially can overcome the energy efficiency limit for conventional CMOS technology due to several key characteristics, including zero OFF-state leakage, abrupt switching behavior, and potentially very low active energy consumption. However, two key issues must be addressed for relay technology to reach its full potential: surface oxide formation at the contacting surfaces leading to increased ON-state resistance after switching, and high switching voltages due to strain gradient present within the relay structure. This dissertation advances NEM relay technology by investigating solutions to both of these pressing issues. Ruthenium, whose native oxide is conductive, is proposed as the contacting material to improve relay ON-state resistance stability. Ruthenium-contact relays are fabricated after overcoming several process integration challenges, and show superior ON-state resistance stability in electrical measurements and extended device lifetime. The relay structural film is optimized via stress matching among all layers within the structure, to provide lower strain gradient (below 10E-3/microm -1) and hence lower switching voltage. These advancements in relay technology, along with the integration of a metallic interconnect layer, enable complex relay-based circuit demonstration. In addition to the experimental efforts, this dissertation theoretically analyzes the energy efficiency limit of a NEM switch, which is generally believed to be limited by the surface adhesion energy. New compact (<1 microm2 footprint), low-voltage (<0.1 V) switch designs are proposed to overcome this limit. The results pave a pathway to scaled energy-efficient electronic device technology.

Damage Precursor Identification via Microstructure-Sensitive Nondestructive Evaluation

NASA Astrophysics Data System (ADS)

Wisner, Brian John

Damage in materials is a complex and stochastic process bridging several time and length scales. This dissertation focuses on investigating the damage process in a particular class of precipitate-hardened aluminum alloys which is widely used in automotive and aerospace applications. Most emphasis in the literature has been given either on their ductility for manufacturing purposes or fracture for performance considerations. In this dissertation, emphasis is placed on using nondestructive evaluation (NDE) combined with mechanical testing and characterization methods applied at a scale where damage incubation and initiation is occurring. Specifically, a novel setup built inside a Scanning Electron Microscope (SEM) and retrofitted to be combined with characterization and NDE capabilities was developed with the goal to track the early stages of the damage process in this type of material. The characterization capabilities include Electron Backscatter Diffraction (EBSD) and Energy Dispersive Spectroscopy (EDS) in addition to X-ray micro-computed tomography (μ-CT) and nanoindentation, in addition to microscopy achieved by the Secondary Electron (SE) and Back Scatter Electron (BSE) detectors. The mechanical testing inside the SEM was achieved with the use of an appropriate stage that fitted within its chamber and is capable of applying both axial and bending monotonic and cyclic loads. The NDE capabilities, beyond the microscopy and μ-CT, include the methods of Acoustic Emission and Digital Image Correlation (DIC). This setup was used to identify damage precursors in this material system and their evolution over time and space. The experimental results were analyzed by a custom signal processing scheme that involves both feature-based analyses as well as a machine learning method to relate recorded microstructural data to damage in this material. Extensions of the presented approach to include information from computational methods as well as its applicability to other material systems are discussed.

Flow Quantification by Nuclear Magnetic Resonance Imaging

NASA Astrophysics Data System (ADS)

Vu, Anthony Tienhuan

1994-01-01

In this dissertation, a robust method for the measurement and visualization of flow field in laminar, complex and turbulent flows by Nuclear Magnetic Resonance Imaging utilizing flow induced Adiabatic Fast Passage (AFP) principle will be presented. This dissertation focuses on the application of AFP in spatially resolvable size vessels. We first review two main flow effects in NMR: time-of-flight and phase dispersion. The discussion of NMR flow imaging application - flow measurements and NMR angiography will be given. The theoretical framework of adiabatic passage will be discussed in order to explain the principle of flow-induced adiabatic passage tagging for flow imaging applications. From a knowledge of the basic flow-induced adiabatic passage principle, we propose a multi-zone AFP excitation scheme to deal with flow in a curved tube, branches and constrictions, i.e. complex and turbulent flow regimes. The technique provides a quick and simple way to acquire flow profiles simultaneously at several locations and arbitrary orientations inside the field-of-view. The flow profile is the time-averaged evolution of the labeled flowing material. Results obtained using a carotid bifurcation and circular jet phantoms are similar to the previous experimental studies employing laser Doppler Anemometry, and other flow visualization techniques. In addition, the preliminary results obtained with a human volunteer support the feasibility of the technique for in vivo flow quantification. Finally, a quantitative comparison of flow measurement of the new proposed techniques with the more established Phase Contrast MRA was performed. The results show excellent correlation between the two methods and with the standard volumetric flow rate measurement indicating that the flow measurements obtained using this technique are reliable and accurate under various flow regimes.

Biofluid lubrication for artificial joints

NASA Astrophysics Data System (ADS)

Pendleton, Alice Mae

This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. Base fluids were studied through comparison of synthetic fluids (simulated body fluid and hyaluronic acid) as well as natural biofluids (from dogs, horses, and humans) in terms of viscosity and fluid shear stress. The nano-structured biofluids were formed using molecules having well-defined shapes. Understanding nano-structured biofluids leads to new ways of design and synthesis of biofluids that are beneficial for artificial joint performance. Experimental approaches were utilized in the present research. This includes basic analysis of biofluids' property, such as viscosity, fluid shear stress, and shear rate using rheological experiments. Tribological investigation and surface characterization were conducted in order to understand effects of molecular and nanostructures on fluid lubrication. Workpiece surface structure and wear mechanisms were investigated using a scanning electron microscope and a transmission electron microscope. The surface topography was examined using a profilometer. The results demonstrated that with the adding of solid additives, such as crown ether or fullerene acted as rough as the other solids in the 3-body wear systems. In addition, the fullerene supplied low friction and low wear, which designates the lubrication purpose of this particular particle system. This dissertation is constructed of six chapters. The first chapter is an introduction to body fluids, as mentioned earlier. After Chapter II, it examines the motivation and approach of the present research, Chapter III discusses the experimental approaches, including materials, experimental setup, and conditions. In Chapter IV, lubrication properties of various fluids are discussed. The tribological properties and performance nanostructured biofluids are discussed in Chapter V, followed by summary and conclusions in Chapter VI.

Linking Adverbials in Academic Writing on Applied Linguistics by Chinese Doctoral Students

ERIC Educational Resources Information Center

Lei, Lei

2012-01-01

The present paper reports an investigation into the use of linking adverbials in the academic writing of Chinese doctoral students. The learner corpus used in the present study is composed of 20 applied linguistics doctoral dissertations. We also compiled a control corpus of 120 published articles in six international journals of applied…

Generating Descriptions of Motion from Cognitive Representations

ERIC Educational Resources Information Center

Keil, Benjamin

2010-01-01

This dissertation presents a novel method of sentence generation, drawing on the insight from Cognitive Semantics (Talmy, 2000a,b) that the effect of uttering a sentence is to evoke a Cognitive Representation in the mind of the listener. Under the assumption that this Cognitive Representation is also present in the speaker and defines (part of)…

Can You Teach in a Normal Way? Examining Chinese and US Curricula's Approach to Teaching Fraction Divisions

ERIC Educational Resources Information Center

Feil, YingYing Crystal

2010-01-01

This dissertation presents two studies designed to examine the topic of fraction division in selected Chinese and US curricula. By comparing the structure and content of the Chinese and "Everyday Mathematics" textbooks and teacher's guides, Study 1 revealed many different features presented in the selected curricula. Major differences…

A Computerized Information System Model for Decision Making for the Oklahoma State Department of Vocational and Technical Education.

ERIC Educational Resources Information Center

Smith, Hubert Gene

The objectives of the study presented in the dissertation were to identify present and anticipated information requirements of the various departments within the Oklahoma State Department of Vocational and Technical Education, to design a computerized information system model utilizing an integrated systems concept to meet information…

Diapers, Dissertations, and Other Holy Things: The Experiences of Mothers Working in Christian Colleges and Universities

ERIC Educational Resources Information Center

Hall, M. Elizabeth Lewis; Anderson, Tamara L.; Willingham, Michele M.

2004-01-01

Academic institutions present specific challenges to women attempting to balance work and family responsibilities. This type of involvement within the subculture of evangelical Christianity presents its own variations. Interviews with 30 mothers working in Christian academia were analyzed using a post hoc content analysis informed by principles of…

A Summary of Research in Science Education--1984.

ERIC Educational Resources Information Center

Lawson, Anton E.; And Others

This review covers approximately 300 studies, including journal articles, dissertations, and papers presented at conferences. The studies are organized under these major headings: status surveys; scientific reasoning; elementary school science (student achievement, student conceptions/misconceptions, student curiosity/attitudes, teaching methods,…

Scalable Domain Decomposed Monte Carlo Particle Transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, Matthew Joseph

2013-12-05

In this dissertation, we present the parallel algorithms necessary to run domain decomposed Monte Carlo particle transport on large numbers of processors (millions of processors). Previous algorithms were not scalable, and the parallel overhead became more computationally costly than the numerical simulation.

Mandatory Open Access Publishing for Electronic Theses and Dissertations: Ethics and Enthusiasm

ERIC Educational Resources Information Center

Hawkins, Ann R.; Kimball, Miles A.; Ives, Maura

2013-01-01

This article argues against policies that require students to submit theses and dissertations to electronic institutional repositories. The article counters a variety of arguments often used to justify this practice. In addition, the article reports on the results of an examination of electronic thesis and dissertation policies at more than 150…

Examining Emotional Intelligence and Perceived Leadership Practices among College Enrollment Services Administrators: A Descriptive Study

ERIC Educational Resources Information Center

Relken, Nathan A.

2014-01-01

This dissertation is the capstone composition of a professional practices doctorate program. The preface includes a brief history and background on the doctorate in education, and more specifically the definition of and rationale behind a professional practices doctoral program and dissertation, a description of the dissertation format and it…

Do Open Access Electronic Theses and Dissertations Diminish Publishing Opportunities in the Sciences?

ERIC Educational Resources Information Center

Ramírez, Marisa L.; McMillan, Gail; Dalton, Joan T.; Hanlon, Ann; Smith, Heather S.; Kern, Chelsea

2014-01-01

In academia, there is a growing acceptance of sharing the final electronic version of graduate work, such as a thesis or dissertation, in an online university repository. Though previous studies have shown that journal editors are willing to consider manuscripts derived from electronic theses and dissertations (ETDs), faculty advisors and graduate…

Supervisors' On-Script Feedback Comments on Drafts of Dissertations: Socialising Students into the Academic Discourse Community

ERIC Educational Resources Information Center

Basturkmen, Helen; East, Martin; Bitchener, John

2014-01-01

Supervising masters and doctoral dissertations is a key function of teaching in higher education and giving written feedback on draft sections is an essential component of this function. However, the specific types of response that supervisors give to their dissertation students' written work have received limited research interest to date. The…

Motives for Dissertation Research at the Intersection between Rural Education and Curriculum and Instruction

ERIC Educational Resources Information Center

Howley, Craig B.; Howley, Aimee; Yahn, Jacqueline

2014-01-01

Dissertation literature focusing on issues of curriculum and instruction (C&I) in rural schools has substantially increased since 1987. We located 580 possibly rural C&I dissertations and subsequently identifi ed 194 as probably rural; of these we were able to obtain digital copies of 188 full-length studies. Our purpose was to…

A Survey of Mathematics Education Technology Dissertation Scope and Quality: 1968-2009

ERIC Educational Resources Information Center

Ronau, Robert N.; Rakes, Christopher R.; Bush, Sarah B.; Driskell, Shannon O.; Niess, Margaret L.; Pugalee, David K.

2014-01-01

We examined 480 dissertations on the use of technology in mathematics education and developed a Quality Framework (QF) that provided structure to consistently define and measure quality. Dissertation studies earned an average of 64.4% of the possible quality points across all methodology types, compared to studies in journals that averaged 47.2%.…

Examining Graduate Dissertations in the Field of Critical Thinking: A Case from Turkey

ERIC Educational Resources Information Center

Demirel, Melek; Derman, Ipek; Can Aran, Ozge

2017-01-01

Purpose: The aim of this study is to conduct content analyses of graduate dissertations about critical thinking skills in the field of educational sciences in Turkey and to document general trends in dissertations. Research Methods: This study is constructed using qualitative research methods and techniques. A document review was used to gather…

Ethnic Folklife Dissertations from the United States and Canada, 1960-1980. A Selected, Annotated Bibliography.

ERIC Educational Resources Information Center

Kerst, Catherine Hiebert

This annotated bibliography lists over 220 multi-disciplinary Ph.D. dissertations written between 1960 and 1980 on the subject of indigenous and immigrant ethnic folklife in the United States and Canada. Only dissertations providing substantial attention to traditional forms of ethnic folk culture in context were considered. The concept of…

Technical Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January 1975 through December 1983 (Vols. 37 through 44).

ERIC Educational Resources Information Center

Murdock, Phil, Comp.

Compiled from responses to a survey of 36 universities offering doctorates in rhetoric, composition, language, or technical communication, and updated using research and dissertation indexes and bibliographies, this bibliography summarizes doctoral research in technical communication since 1975. The 35 titles deal with a variety of topics,…

The Adviser and the Committee

ERIC Educational Resources Information Center

Cassuto, Leonard

2012-01-01

The dissertation adviser's task may be to give advice, but his or her approval is required for the thesis to pass and the degree to be awarded. It is the graduate student's dissertation, but the imprimatur belongs to the dissertation adviser, so perhaps the process belongs to both of them. But that equation leaves out some other important actors,…

The Effects of Program Structure on Dissertation Writing in "Online Academia": A Qualitative Analysis of Online Doctoral Student Experiences

ERIC Educational Resources Information Center

Goodwin-Lee, Regina

2010-01-01

Writing the dissertation can be one of the most stressful experiences in the doctoral education experience. Previous research findings indicate that traditional psychology doctoral candidates (PDC) identify the graduate school experience, and the dissertation process in particular as stress-inducing, isolating and key obstacles to graduation.…

A Study of Factors Related to Dissertation Progress among Doctoral Candidates: Focus on Students' Research Self-Efficacy as a Result of Their Research Training and Experiences.

ERIC Educational Resources Information Center

Faghihi, Forooz; Rakow, Ernest A.; Ethington, Corinna

This study examined relationships among doctoral candidates' background characteristics, research preparation, research environment, research involvement, student-advisor relationship, research self-efficacy, and dissertation progress. The study focused on differences in research self-efficacy and dissertation progress among students from the…

Measuring Educational Quality by Appraising Theses and Dissertations: Pitfalls and Remedies

ERIC Educational Resources Information Center

Hamilton, Patti; Johnson, Robert; Poudrier, Chelsey

2010-01-01

In this paper, we argue that, as indicators of the educational quality of graduate degree programs, student theses and dissertations are best used in specific contexts. High-quality theses and dissertations, that is, may be the result of factors such as verbal skills students already possessed at admission or of complex interactions between…

Dissertation Research in School Psychology: Changes in Topics and Methodology over the Past 25 Years

ERIC Educational Resources Information Center

Lekwa, Adam; Ysseldyke, Jim

2010-01-01

Eighty school psychology programs offering training at the doctoral level were contacted with a request for lists of authors, titles, and abstracts of dissertations completed between the years 2000 and 2007. Titles and abstracts from 1119 dissertations were reviewed to assess the interests and experiences of new researchers and practitioners in…

A Microscope or a Mirror?: A Question of Study Validity Regarding the Use of Dissertation Citation Analysis for Evaluating Research Collections

ERIC Educational Resources Information Center

Beile, Penny M.; Boote, David N.; Killingsworth, Elizabeth K.

2004-01-01

Use of dissertation citation analysis for collection evaluation was investigated. Analysis of 1842 education dissertation citations from three institutions suggests the assumption of doctoral student expertise in their use of the scholarly literature may be overstated. For purposes of developing research collections, dependence on dissertation…

The Significance and Use of Historical Method in Library and Information Science Dissertations, 1984-1999.

ERIC Educational Resources Information Center

Thompson, Heather A.

This study is concerned with the importance of historical method in library and information science research. The research conducted in this study specifically examined library and information science doctoral dissertations written between 1984-1999. The study of the "Digital Dissertations" database found that only eight to seventeen percent of…

To Gain the Academic Capital: The Conflict and Solution in the Dissertation Proposal Defence

ERIC Educational Resources Information Center

Ningning, Zhao

2006-01-01

Doctor candidates get the academic identity and academic capital in his field by the thesis writing. The dissertation proposal defence hold on the public field promotes the state of academic and legalizes the discipline of the academic community. During the dissertation proposal defence, doctor candidates may face three conflicts. The first is…

Advanced methods for controlling untethered magnetic devices using rotating magnetic fields

NASA Astrophysics Data System (ADS)

Mahoney, Arthur W., Jr.

This dissertation presents results documenting advancements on the control of untethered magnetic devices, such as magnetic "microrobots" and magnetically actuated capsule endoscopes, motivated by problems in minimally invasive medicine. This dissertation focuses on applying rotating magnetic fields for magnetic manipulation. The contributions include advancements in the way that helical microswimmers (devices that mimic the propulsion of bacterial flagella) are controlled in the presence of gravitational forces, advancements in ways that groups of untethered magnetic devices can be differentiated and semi-independently controlled, advancements in the way that untethered magnetic device can be controlled with a single rotating permanent magnet, and an improved understanding in the nature of the magnetic force applied to an untethered device by a rotating magnet.

Transportation network policy modeling for congestion and pollution control: A variational inequality approach

NASA Astrophysics Data System (ADS)

Ramanujam, Padma

1999-08-01

Public concern over the state of the environment has grown over the past decade. All indications are that this concern will continue to influence policy making into the foreseeable future. Road transport is seen as the major contributor to environmental degradation. Transportation planners around the world face the question: cleaner air and/or faster commutes? While individual vehicles can be made more environmentally friendly, the sheer scale of growth in world-wide vehicle numbers is projected to cause significant environmental degradation in the longer run, and in the absence of newer and stricter polices. It is a challenge for governments to find policies that ensure congestion-free metropolitan areas while guaranteeing both critical environmental quality levels and a sufficient infrastructure access to all groups involved. The objective of the dissertation is to provide a mathematical framework to study transportation policy models for the purpose of controlling congestion and pollution. Towards this objective. a series of transportation policy models are developed to study travel behavior and to quantity the reductions in congestion and automobile emissions. The dissertation begins with a brief historical overview of some of the pioneering works in urban transportation economics and later presents the theoretical foundation for the transportation policy models developed. The dissertation introduces single modal and multimodal transportation network policy models that accomplish road pricing with the imposition of goal targets on link loads. as well as, integrated traffic equilibrium models with marketable mobile emission permits. Furthermore, equilibrium conditions are derived for each model, and both qualitative analysis and computational procedures are studied. Finally, the dissertation concludes with a comparative study of the relationship between regulatory pricing models and marketable emission permit transportation models and a discussion on key factors that influence implementation of the proposed policy models. The framework of variational inequalities has been utilized in our dissertation, because it is ideal for equilibrium systems. With the addition of pricing policy interventions and the integration of marketable mobile emission permits, traffic equilibrium models become extremely complex. Consequently, the computation of the equilibrium is made more difficult. However, it is shown in the dissertation that in addition to pricing interventions and the integration of a marketable emission permit system that it is possible to incorporate multiple modes of transport and even to handle the issue of noncompliance, using the framework of variational inequalities.

Investigating lightning-to-ionosphere energy coupling based on VLF lightning propagation characterization

NASA Astrophysics Data System (ADS)

Lay, Erin Hoffmann

In this dissertation, the capabilities of the World-Wide Lightning Location Network (WWLLN) are analyzed in order to study the interactions of lightning energy with the lower ionosphere. WWLLN is the first global ground-based lightning location network and the first lightning detection network that continuously monitors lightning around the world in real time. For this reason, a better characterization of the WWLLN could allow many global atmospheric science problems to be addressed, including further investigation into the global electric circuit and global mapping of regions of the lower ionosphere likely to be impacted by strong lightning and transient luminous events. This dissertation characterizes the World-Wide Location Network (WWLLN) in terms of detection efficiency, location and timing accuracy, and lightning type. This investigation finds excellent timing and location accuracy for WWLLN. It provides the first experimentally-determined estimate of relative global detection efficiency that is used to normalize lightning counts based on location. These normalized global lightning data from the WWLLN are used to map intense storm regions around the world with high time and spatial resolution as well as to provide information on energetic emissions known as elves and terrestrial gamma-ray flashes (TGFs). This dissertation also improves WWLLN by developing a procedure to provide the first estimate of relative lightning stroke radiated energy in the 1-24 kHz frequency range by a global lightning detection network. These characterizations and improvements to WWLLN are motivated by the desire to use WWLLN data to address the problem of lightning-to-ionosphere energy coupling. Therefore, WWLLN stroke rates are used as input to a model, developed by Professor Mengu Cho at the Kyushu Institute of Technology in Japan, that describes the non-linear effect of lightning electromagnetic pulses (EMP) on the ionosphere by accumulating electron density changes resulting from the interaction of the EMP of ten successive lightning strokes with the lower ionosphere. Further studies must be completed to narrow uncertainties in the model, but the qualitative ionospheric response to successive EMPs is presented. Results from this study show that the non-linear effect of lightning EMP due to successive lightning strokes must be taken into account, and varies with altitude, such that the most significant electron density enhancement occurs at 88 km altitude.

On-Chip, Amplification-Free Quantification of Nucleic Acid for Point-of-Care Diagnosis

NASA Astrophysics Data System (ADS)

Yen, Tony Minghung

This dissertation demonstrates three physical device concepts to overcome limitations in point-of-care quantification of nucleic acids. Enabling sensitive, high throughput nucleic acid quantification on a chip, outside of hospital and centralized laboratory setting, is crucial for improving pathogen detection and cancer diagnosis and prognosis. Among existing platforms, microarray have the advantages of being amplification free, low instrument cost, and high throughput, but are generally less sensitive compared to sequencing and PCR assays. To bridge this performance gap, this dissertation presents theoretical and experimental progress to develop a platform nucleic acid quantification technology that is drastically more sensitive than current microarrays while compatible with microarray architecture. The first device concept explores on-chip nucleic acid enrichment by natural evaporation of nucleic acid solution droplet. Using a micro-patterned super-hydrophobic black silicon array device, evaporative enrichment is coupled with nano-liter droplet self-assembly workflow to produce a 50 aM concentration sensitivity, 6 orders of dynamic range, and rapid hybridization time at under 5 minutes. The second device concept focuses on improving target copy number sensitivity, instead of concentration sensitivity. A comprehensive microarray physical model taking into account of molecular transport, electrostatic intermolecular interactions, and reaction kinetics is considered to guide device optimization. Device pattern size and target copy number are optimized based on model prediction to achieve maximal hybridization efficiency. At a 100-mum pattern size, a quantum leap in detection limit of 570 copies is achieved using black silicon array device with self-assembled pico-liter droplet workflow. Despite its merits, evaporative enrichment on black silicon device suffers from coffee-ring effect at 100-mum pattern size, and thus not compatible with clinical patient samples. The third device concept utilizes an integrated optomechanical laser system and a Cytop microarray device to reverse coffee-ring effect during evaporative enrichment at 100-mum pattern size. This method, named "laser-induced differential evaporation" is expected to enable 570 copies detection limit for clinical samples in near future. While the work is ongoing as of the writing of this dissertation, a clear research plan is in place to implement this method on microarray platform toward clinical sample testing for disease applications and future commercialization.

Laser guidance of mesoscale particles

NASA Astrophysics Data System (ADS)

Underdown, Frank Hartman, Jr.

Mesoscale particles are guided and trapped in hollow optical fibers using radiation pressure forces. Laser light from a 0.4W, 780nm diode laser is guided in a low- loss fiber mode and used to generate the guidance forces. Laser scattering and absorption forces propels particles along the fiber and polarization gradient forces attract them to the fiber's axial center. Using two counter propagating laser beams, inside the fiber, particles can be trapped in three dimensions. Measuring the spring constant of the trap gives the gradient force. This dissertation describes Rayleigh and Mie scattering models for calculating guidance forces. Calculated forces as a function of particle size and composition (i.e. dielectric, semiconductor, and metals) will be presented. For example, under typical experimental conditions 100nm Au particles are guided by a 2 × 10-14 N propulsive force in a water filled fiber. In comparison, the measured force, obtained from the particle's velocity and Stokes' law, is 7.98 × 10-14 N.

Strange quark contribution to the nucleon

NASA Astrophysics Data System (ADS)

Darnell, Dean F.

The strangeness contribution to the electric and magnetic properties of the nucleon has been under investigation experimentally for many years. Lattice Quantum Chromodynamics (LQCD) gives theoretical predictions of these measurements by implementing the continuum gauge theory on a discrete, mathematical Euclidean space-time lattice which provides a cutoff removing the ultra-violet divergences. In this dissertation we will discuss effective methods using LQCD that will lead to a better determination of the strangeness contribution to the nucleon properties. Strangeness calculations are demanding technically and computationally. Sophisticated techniques are required to carry them to completion. In this thesis, new theoretical and computational methods for this calculation such as twisted mass fermions, perturbative subtraction, and General Minimal Residual (GMRES) techniques which have proven useful in the determination of these form factors will be investigated. Numerical results of the scalar form factor using these techniques are presented. These results give validation to these methods in future calculations of the strange quark contribution to the electric and magnetic form factors.

Visualizing Transcranial Direct Current Stimulation (tDCS) in vivo using Magnetic Resonance Imaging

NASA Astrophysics Data System (ADS)

Jog, Mayank Anant

Transcranial Direct Current Stimulation (tDCS) is a low-cost, non-invasive neuromodulation technique that has been shown to treat clinical symptoms as well as improve cognition. However, no techniques exist at the time of research to visualize tDCS currents in vivo. This dissertation presents the theoretical framework and experimental implementations of a novel MRI technique that enables non-invasive visualization of the tDCS electric current using magnetic field mapping. The first chapter establishes the feasibility of measuring magnetic fields induced by tDCS currents. The following chapter discusses the state of the art implementation that can measure magnetic field changes in individual subjects undergoing concurrent tDCS/MRI. The final chapter discusses how the developed technique was integrated with BOLD fMRI-an established MRI technique for measuring brain function. By enabling a concurrent measurement of the tDCS current induced magnetic field as well as the brain's hemodynamic response to tDCS, our technique opens a new avenue to investigate tDCS mechanisms and improve targeting.

High accuracy broadband infrared spectropolarimetry

NASA Astrophysics Data System (ADS)

Krishnaswamy, Venkataramanan

Mueller matrix spectroscopy or Spectropolarimetry combines conventional spectroscopy with polarimetry, providing more information than can be gleaned from spectroscopy alone. Experimental studies on infrared polarization properties of materials covering a broad spectral range have been scarce due to the lack of available instrumentation. This dissertation aims to fill the gap by the design, development, calibration and testing of a broadband Fourier Transform Infra-Red (FT-IR) spectropolarimeter. The instrument operates over the 3-12 mum waveband and offers better overall accuracy compared to the previous generation instruments. Accurate calibration of a broadband spectropolarimeter is a non-trivial task due to the inherent complexity of the measurement process. An improved calibration technique is proposed for the spectropolarimeter and numerical simulations are conducted to study the effectiveness of the proposed technique. Insights into the geometrical structure of the polarimetric measurement matrix is provided to aid further research towards global optimization of Mueller matrix polarimeters. A high performance infrared wire-grid polarizer is characterized using the spectropolarimeter. Mueller matrix spectrum measurements on Penicillin and pine pollen are also presented.

3D finite element modeling of sliding wear

NASA Astrophysics Data System (ADS)

Buentello Hernandez, Rodolfo G.

Wear is defined as "the removal of material volume through some mechanical process between two surfaces". There are many mechanical situations that can induce wear and each can involve many wear mechanisms. This research focuses on the mechanical wear due to dry sliding between two surfaces. Currently there is a need to identify and compare materials that would endure sliding wear under severe conditions such as high velocities. The high costs associated with the field experimentation of systems subject to high-speed sliding, has prevented the collection of the necessary data required to fully characterize this phenomena. Simulating wear through Finite Elements (FE) would enable its prediction under different scenarios and would reduce experimentation costs. In the aerospace, automotive and weapon industries such a model can aid in material selection, design and/or testing of systems subjected to wear in bearings, gears, brakes, gun barrels, slippers, locomotive wheels, or even rocket test tracks. The 3D wear model presented in this dissertation allows one to reasonably predict high-speed sliding mechanical wear between two materials. The model predictions are reasonable, when compared against those measured on a sled slipper traveling over the Holloman High Speed Tests Track. This slipper traveled a distance of 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s.

Gaussian Finite Element Method for Description of Underwater Sound Diffraction

NASA Astrophysics Data System (ADS)

Huang, Dehua

A new method for solving diffraction problems is presented in this dissertation. It is based on the use of Gaussian diffraction theory. The Rayleigh integral is used to prove the core of Gaussian theory: the diffraction field of a Gaussian is described by a Gaussian function. The parabolic approximation used by previous authors is not necessary to this proof. Comparison of the Gaussian beam expansion and Fourier series expansion reveals that the Gaussian expansion is a more general and more powerful technique. The method combines the Gaussian beam superposition technique (Wen and Breazeale, J. Acoust. Soc. Am. 83, 1752-1756 (1988)) and the Finite element solution to the parabolic equation (Huang, J. Acoust. Soc. Am. 84, 1405-1413 (1988)). Computer modeling shows that the new method is capable of solving for the sound field even in an inhomogeneous medium, whether the source is a Gaussian source or a distributed source. It can be used for horizontally layered interfaces or irregular interfaces. Calculated results are compared with experimental results by use of a recently designed and improved Gaussian transducer in a laboratory water tank. In addition, the power of the Gaussian Finite element method is demonstrated by comparing numerical results with experimental results from use of a piston transducer in a water tank.

Single- or multiple-visit endodontics: which technique results in fewest postoperative problems?

PubMed

Balto, Khaled

2009-01-01

The Cochrane Central Register of Controlled Trials, Medline, Embase, six thesis databases (Networked Digital Library of Theses and Dissertations, Proquest Digital Dissertations, OAIster, Index to Theses, Australian Digital Thesis Program and Dissertation.com) and one conference report database (BIOSIS Previews) were searched. There were no language restrictions. Studies were included if subjects had a noncontributory medical history; underwent nonsurgical root canal treatment during the study; there was comparison between single- and multiple-visit root canal treatment; and if outcome was measured in terms of pain degree or prevalence of flare-up. Data were extracted using a standard data extraction sheet. Because of variations in recorded outcomes and methodological and clinical heterogeneity, a meta-analysis was not carried out, although a qualitative synthesis was presented. Sixteen studies fitted the inclusion criteria in the review, with sample size varying from 60-1012 cases. The prevalence of postoperative pain ranged from 3-58%. The heterogeneity of the included studies was far too great to yield meaningful results from a meta-analysis. Compelling evidence is lacking to indicate any significantly different prevalence of postoperative pain or flare-up following either single- or multiple-visit root canal treatment.

Selected Reference Books of 1971-72

ERIC Educational Resources Information Center

Sheehy, Eugene P.

1973-01-01

The purpose of this annotated list is to present a selection of recent scholarly and foreign works of interest to reference workers in university libraries. The citations are listed under the following headings: guide, bibliography, encyclopedias, dictionaries, newspapers, dissertations, biography, genealogy, literature, education, sociology,…

Speech Communication and Communication Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," April and May 1978 (Vol. 38 Nos. 10 and 11).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 25 titles deal with a variety of topics, including the following: the nature of creativity in advertising communication; speech communication difficulties of international professors; rhetorical arguments regarding the…

Real Fantasies in Mathematics Education: Numeracy, Quantitative Reasoners, and Transdisciplinary Wicked Problems

ERIC Educational Resources Information Center

Craig, Jeffrey Carl

2017-01-01

This dissertation has seven chapters. In chapter one, I discuss through why I am doing this dissertation, my positionality, and how I learned from and with all of my committee members. Chapter two is where I situate my dissertation study through developing a social theory of quantitative literacy by translating a social theory of literacy (Barton…

A Celebration of Diversity: LIS Research in the Nordic Countries as Shown by PhD Dissertations 2005-2014

ERIC Educational Resources Information Center

Tveit, Åse Kristine

2017-01-01

A study of PhD dissertations in library and information science (LIS) was carried out to investigate which research topics have been of interest in Nordic LIS institutions. Seventy-nine doctoral dissertations from 2005 to 2014, published by 13 different research institutions, were retrieved from the institutions' archives and from library…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," October 1978 through June 1979 (Vol. 39 Nos. 4 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 20 titles deal with the following topics: written communication competencies necessary in the accounting profession; the cooperative school approach to developing a communication network; organizational communication and faculty…

Scholarly Capacities, Habits of Mind, and Dispositions: Case Studies of Education Doctoral Students in a Dissertation Proposal Seminar

ERIC Educational Resources Information Center

McArthur, Dana Lynn

2011-01-01

The completion of a formal proposal for a dissertation research project is a standard requirement as a prelude to the process of conducting research and writing a doctoral dissertation for students who complete a doctoral degree in most academic fields including all the branches of the field of education. Many students satisfactorily complete…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1983 (Vol. 43 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 45 titles deal with a variety of topics, including the following: (1) the relationship of Jungian psychological traits and the effects of comparative advertising; (2) processing and reconstructing television narrative content;…

Teaching of Writing: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1979 (Vol. 39 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 19 titles deal with the following topics: the dynamics of creative expression, modular scheduling and student success in freshman composition, growth in writing ability through immersion in a university discipline, massed and…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1984 (Vol. 45 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 16 titles deal with the following topics: (1) women proteges' perceptions of the mentoring process; (2) the relationship between opportunity for upward communication and facets of job satisfaction; (3) the organizational…

Theses and Dissertations Completed in Family and Consumer Sciences: 1995. [and] A Listing of Theses and Dissertations Completed in Family and Consumer Sciences: 1995.

ERIC Educational Resources Information Center

Lee, Mi-Young; Johnson, Kim K. P.

1996-01-01

Five tables summarize by institution and subject matter 753 theses and dissertations in family and consumer sciences in 1995. The listing is organized by the following categories: art and design; child development; clothing; consumer resource management; family relations; foods; home economics education; human environment/housing; hotel/restaurant…

Theses and Dissertations Completed in Family and Consumer Sciences: 1996. [and] A Listing of Theses and Dissertations Completed in Family and Consumer Sciences: 1996.

ERIC Educational Resources Information Center

Ownbey, Shiretta E.; Taupmann, Ann

1997-01-01

Five tables summarize by institution and subject matter 612 theses and dissertations in family and consumer sciences in 1996. The listing is organized by the following categories: art and design; child development; clothing/apparel; consumer resource management; family relations; foods; human environment/housing; hotel/restaurant management;…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1982 (Vol. 43 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 32 titles discuss a variety of topics, including the following: (1) the elderly audience for religious broadcasting; (2) response to television advertising of directly marketed products; (3) the effectiveness of documentary film…

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through September 1978 (Vol. 39 Nos. 1 through 3).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 12 titles deal with the following topics: advance organizers; a comparison of the effectiveness and efficiency of behavioral objectives and sample tests; anaphoric nominal substitution and its relationship to reading…

Analysis of Citations to Books in Chemistry PhD Dissertations in an Era of Transition

ERIC Educational Resources Information Center

Flaxbart, David

2018-01-01

A citation analysis of chemistry PhD dissertations at the University of Texas at Austin yielded data on how often graduate students cite books in their bibliographies, and on the characteristics of the books cited, in terms of age and local ownership. The analysis examined samples of dissertations selected from five discrete years--1988, 2006,…

Journalism and Journalism Education: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1978 (Vol. 38 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 11 titles deal with the following topics: the role and function of the California Journalism Articulation Committee; international communication as an academic career for journalism professors; network television news discourse;…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1983 (Vol. 44 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 27 titles deal with a variety of topics, including the following: (1) children's understanding of television advertising; (2) the occupational role portrayed of women in magazine advertisements; (3) the relationship between…

Speech Communication and Communication Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," August and September 1978 (Vol. 39 Nos. 2 and 3).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 titles deal with the following topics: the rhetorical dimensions of nondiscursive, fragmentary communication; perceptions of persuasion situations and the question of transituational consistency of behavior; alcohol use and…

Strategies for Finding and Selecting an Ideal Thesis or Dissertation Topic: A Review of Literature

ERIC Educational Resources Information Center

Lei, Simon A.

2009-01-01

Choosing an ideal master's thesis or doctoral dissertation topic is probably one of the most important decisions students will make while in graduate school. Some graduate students may spend a year or even longer looking for potential topics before finally selecting one for their thesis or dissertation. There are a number of successful strategies…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1979 (Vol. 40 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 12 titles deal with a variety of topics, including the following: communication and perceptions of organizational climate; perceptions of communications between federal and local educational agencies; intraorganizational conflict…

Reading Instruction: Preschool and Elementary: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," April through June 1978 (Vol. 38 Nos. 10 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 22 titles deal with the following topics: computer-assisted instruction; school characteristics and reading achievement; the process of reading acquisition; on-task behavior, teacher involvement, and reading achievement; the…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1981 (Vol. 41 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 12 titles deal with the following topics: (1) identifying problem formation behaviors within the process of organizational change; (2) using the communication audit to determine decision style, satisfaction, and communication…

Drama and Oral Interpretation: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1978 (Vol. 39 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 titles deal with the following topics: interpersonal conflict and the nonviolent peacemaking tradition; theatrical transactional analysis; recycling existing spaces for theatre use; the effect of theatre study on the…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1979 (Vol. 39 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 29 titles deal with a variety of topics, including the following: the mythology underlying television advertising; the ethnicity of television commercials; the impact of television food commercials on young children; comparative…

What Does Research Tell Us about Trends in Dissertations on PBL?

ERIC Educational Resources Information Center

Erdogan, Tolga

2017-01-01

The aim of this study is to investigate the research trends in dissertations on PBL from 2002 to 2015 in Turkey. For this purpose, the master's and doctorate dissertations in the National Thesis Database of Council of Higher Education (CoHE) were selected for rigorous content analysis. The analysis was utilized to classify the type of study, the…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1985 (Vol. 46 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 35 titles deal with a variety of topics, including the following: (1) television and scholastic achievement; (2) press freedom and the new world information order; (3) content analysis of Saturday morning children's television…

An Investigation of the North Carolina Center for the Advancement of Teaching and Its Possible Influence on Beginning Teacher Retention: A Companion Dissertation

ERIC Educational Resources Information Center

Shook, Anna Lorraine Braverman

2015-01-01

An Investigation of the North Carolina Center for the Advancement of Teaching and its Influence on Beginning Teacher Retention: A Companion Dissertation. Shook, Anna, 2015. Dissertation, Gardner-Webb University, Adult Learning Theory/Adult Developmental Theory/Professional Development/Beginning Teacher/North Carolina Center for the Advancement of…

Applied Communication, Argumentation, and Debate: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1983 (Vol. 44 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 13 titles deal with the following topics: (1) collective bargaining in higher education; (2) decoding nonverbal communication and clinical effectiveness; (3) the need for interpersonal communication training for Texas peace…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1981 (Vol. 42 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 11 titles deal with the following topics: (1) transnational communication knowledge transfer and utilization, especially between the United States and Asian countries; (2) police personnel evaluation procedures as an aspect of…

Overview of the Dissertation Process within the Framework of Flow Theory: A Qualitative Study

ERIC Educational Resources Information Center

Cakmak, Esra; Oztekin, Ozge; Isci, Sabiha; Danisman, Sahin; Uslu, Fatma; Karadag, Engin

2015-01-01

The purpose of this study is to examine the flow of doctoral students who are also research assistants and in the dissertation process. The study was designed using the case study method. The case undertaken in the study was the dissertation process. Eleven participants were selected into the study using maximum variation sampling. Face-to-face,…

Experimental Constraints of the Exotic Shearing of Space-Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richardson, Jonathan William

2016-08-01

The Holometer program is a search for rst experimental evidence that space-time has quantum structure. The detector consists of a pair of co-located 40-m power-recycled interferometers whose outputs are read out synchronously at 50 MHz, achieving sensitivity to spatiallycorrelated uctuations in dierential position on time scales shorter than the light-crossing time of the instruments. Unlike gravitational wave interferometers, which time-resolve transient geometrical disturbances in the spatial background, the Holometer is searching for a universal, stationary quantization noise of the background itself. This dissertation presents the nal results of the Holometer Phase I search, an experiment congured for sensitivity to exoticmore » coherent shearing uctuations of space-time. Measurements of high-frequency cross-spectra of the interferometer signals obtain sensitivity to spatially-correlated eects far exceeding any previous measurement, in a broad frequency band extending to 7.6 MHz, twice the inverse light-crossing time of the apparatus. This measurement is the statistical aggregation of 2.1 petabytes of 2-byte dierential position measurements obtained over a month-long exposure time. At 3 signicance, it places an upper limit on the coherence scale of spatial shear two orders of magnitude below the Planck length. The result demonstrates the viability of this novel spatially-correlated interferometric detection technique to reach unprecedented sensitivity to coherent deviations of space-time from classicality, opening the door for direct experimental tests of theories of relational quantum gravity.« less

Compton Scattering Polarimetry for the Determination of the Proton's Weak Charge Through Measurements of the Parity-Violating Asymmetry of 1H(e,e')p

NASA Astrophysics Data System (ADS)

Cornejo, Juan Carlos

The Standard Model has been a theory with the greatest success in describing the fundamental interactions of particles. As of the writing of this dissertation, the Standard Model has not been shown to make a false prediction. However, the limitations of the Standard Model have long been suspected by its lack of a description of gravity, nor dark matter. Its largest challenge to date, has been the observation of neutrino oscillations, and the implication that they may not be massless, as required by the Standard Model. The growing consensus is that the Standard Model is simply a lower energy effective field theory, and that new physics lies at much higher energies. The Qweak Experiment is testing the Electroweak theory of the Standard Model by making a precise determination of the weak charge of the proton (Qpw). Any signs of "new physics" will appear as a deviation to the Standard Model prediction. The weak charge is determined via a precise measurement of the parity-violating asymmetry of the electron-proton interaction via elastic scattering of a longitudinally polarized electron beam of an un-polarized proton target. The experiment required that the electron beam polarization be measured to an absolute uncertainty of 1 %. At this level the electron beam polarization was projected to contribute the single largest experimental uncertainty to the parity-violating asymmetry measurement. This dissertation will detail the use of Compton scattering to determine the electron beam polarization via the detection of the scattered photon. I will conclude the remainder of the dissertation with an independent analysis of the blinded Qweak.

Autonomous perception and decision making in cyber-physical systems

NASA Astrophysics Data System (ADS)

Sarkar, Soumik

2011-07-01

The cyber-physical system (CPS) is a relatively new interdisciplinary technology area that includes the general class of embedded and hybrid systems. CPSs require integration of computation and physical processes that involves the aspects of physical quantities such as time, energy and space during information processing and control. The physical space is the source of information and the cyber space makes use of the generated information to make decisions. This dissertation proposes an overall architecture of autonomous perception-based decision & control of complex cyber-physical systems. Perception involves the recently developed framework of Symbolic Dynamic Filtering for abstraction of physical world in the cyber space. For example, under this framework, sensor observations from a physical entity are discretized temporally and spatially to generate blocks of symbols, also called words that form a language. A grammar of a language is the set of rules that determine the relationships among words to build sentences. Subsequently, a physical system is conjectured to be a linguistic source that is capable of generating a specific language. The proposed technology is validated on various (experimental and simulated) case studies that include health monitoring of aircraft gas turbine engines, detection and estimation of fatigue damage in polycrystalline alloys, and parameter identification. Control of complex cyber-physical systems involve distributed sensing, computation, control as well as complexity analysis. A novel statistical mechanics-inspired complexity analysis approach is proposed in this dissertation. In such a scenario of networked physical systems, the distribution of physical entities determines the underlying network topology and the interaction among the entities forms the abstract cyber space. It is envisioned that the general contributions, made in this dissertation, will be useful for potential application areas such as smart power grids and buildings, distributed energy systems, advanced health care procedures and future ground and air transportation systems.

Molecular Syntheses of Extended Materials

NASA Astrophysics Data System (ADS)

Paley, Daniel W.

Bottom-up molecular synthesis is a route to chemically and crystallographically uniform polymers and solid-state materials. Through the use of molecular precursors, we gain atomic-level control of functionality and fine-tuning of the collective properties of materials. This dissertation presents two studies that demonstrate this approach. Ring-opening alkyne metathesis polymerization is a possible approach to monodisperse conjugated polymers, but its applications have been limited by difficult syntheses and high air sensitivity of known organometallic ROAMP initiators. We designed a dimeric, air-stable molybdenum alkylidyne with a tris(phenolate) supporting ligand. The precatalyst is activated by addition of methanol and polymerizes cyclooctynes with excellent chemical selectivity and functional group tolerance. The Nuckolls and Roy groups have introduced a new family of solid-state compounds synthesized from cobalt chalcogenide clusters Co6Q 8(PR3)6 and fullerenes. The first examples of these materials crystallized in superatom lattices with the symmetry of simple inorganic solids CdI2 (P-3m1) and NaCl (Fm-3m). This dissertation reveals that further members of the family feature extraordinary diversity of structure, including a pseudo-trigonal array of fulleride dimers in [Co 6Te8(PEt3)6]2[C140 ][C70]2 and a heterolayered van der Waals cocrystal [Co6Se8(PEt2phen)6][C 60]5. In addition to these unusual crystal structures, this dissertation presents a method for assigning redox states from crystallographic data in Co6Q8 clusters. Finally, a detailed guide to the collection and solution of single-crystal X-ray data is presented. The guide is intended for independent study by new crystallographers.

Microphotonic devices for compact planar lightwave circuits and sensor systems

NASA Astrophysics Data System (ADS)

Cardenas Gonzalez, Jaime

2005-07-01

Higher levels of integration in planar lightwave circuits and sensor systems can reduce fabrication costs and broaden viable applications for optical network and sensor systems. For example, increased integration and functionality can lead to sensor systems that are compact enough for easy transport, rugged enough for field applications, and sensitive enough even for laboratory applications. On the other hand, more functional and compact planar lightwave circuits can make optical networks components less expensive for the metro and access markets in urban areas and allow penetration of fiber to the home. Thus, there is an important area of opportunity for increased integration to provide low cost, compact solutions in both network components and sensor systems. In this dissertation, a novel splitting structure for microcantilever deflection detection is introduced. The splitting structure is designed so that its splitting ratio is dependent on the vertical position of the microcantilever. With this structure, microcantilevers sensitized to detect different analytes or biological agents can be integrated into an array on a single chip. Additionally, the integration of a depolarizer into the optoelectronic integrated circuit in an interferometric fiber optic gyroscope is presented as a means for cost reduction. The savings come in avoiding labor intensive fiber pigtailing steps by permitting batch fabrication of these components. In particular, this dissertation focuses on the design of the waveguides and polarization rotator, and the impact of imperfect components on the performance of the depolarizer. In the area of planar lightwave circuits, this dissertation presents the development of a fabrication process for single air interface bends (SAIBs). SAIBs can increase integration by reducing the area necessary to make a waveguide bend. Fabrication and measurement of a 45° SAIB with a bend efficiency of 93.4% for TM polarization and 92.7% for TE polarization are presented.

Nanometer-Thick Yttrium Iron Garnet Film Development and Spintronics-Related Study

NASA Astrophysics Data System (ADS)

Chang, Houchen

In the last decade, there has been a considerable interest in using yttrium iron garnet (Y3Fe5O12, YIG) materials for magnetic insulator-based spintronics studies. This interest derives from the fact that YIG materials have very low intrinsic damping. The development of YIG-based spintronics demands YIG films that have a thickness in the nanometer (nm) range and at the same time exhibit low damping similar to single-crystal YIG bulk materials. This dissertation reports comprehensive experimental studies on nm-thick YIG films by magnetron sputtering techniques. Optimization of sputtering control parameters and post-deposition annealing processes are discussed in detail. The feasibility of low-damping YIG nm-thick film growth via sputtering is demonstrated. A 22.3-nm-thick YIG film, for example, shows a Gilbert damping constant of less than 1.0 x 10-4. The demonstration is of great technological significance because sputtering is a thin film growth technique most widely used in industry. The spin Seebeck effect (SSE) refers to the generation of spin voltage in a ferromagnet (FM) due to a temperature gradient. The spin voltage can produce a pure spin current into a normal metal (NM) that is in contact with the FM. Various theoretical models have been proposed to interpret the SSE, although a complete understanding of the effect has not been realized yet. In this dissertation the study of the role of damping on the SSE in YIG thin films is conducted for the first time. With the thin film development method mentioned in the last paragraph, a series of YIG thin films showing very similar structural and static magnetic properties but rather different Gilbert damping values were prepared. A Pt capping layer was grown on each YIG film to probe the strength of the SSE. The experimental data show that the YIG films with a smaller intrinsic Gilbert damping shows a stronger SSE. The majority of the previous studies on YIG spintronics utilized YIG films that were grown on single-crystal Gd3Ga5O 12 (GGG) substrates first and then capped with either a thin NM layer or a thin topological insulator (TI) layer. The use of the GGG substrates is crucial in terms of realizing high-quality YIG films, because GGG not only has a crystalline structure almost perfectly matching that of YIG but is also extremely stable at high temperature in oxygen that is the condition needed for YIG crystallization. The feasibility of growing high-quality YIG thin films on Pt thin films is explored in this dissertation. This work is of great significance because it enables the fabrication of sandwich-like NM/YIG/NM or NM/YIG/TI structures. Such tri-layered structures will facilitate various interesting fundamental studies as well as device developments. The demonstration of a magnon-mediated electric current drag phenomenon is presented as an example for such tri-layered structures.

Thermal Analysis of LED Phosphor Layer

NASA Astrophysics Data System (ADS)

Perera, Ukwatte Lokuliyanage Indika Upendra

Solid-state lighting technology has progressed to a level where light-emitting diode (LED) products are either on par or better than their traditional lighting technology counterparts with respect to efficacy and lifetime. At present, the most common method to create "white" light from LEDs for illumination applications is by using the LED primary radiation and wavelength-converting materials. In this method, the re-emission from the wavelength-converting materials excited by the LED primary radiation is combined with the LED primary radiation to create the "white" light. During this conversion process, heat is generated as a result of conversion inefficiencies and other loss mechanisms in the LED and the wavelength-converting materials. This generated heat, if not properly dissipated, increases the operating temperature, thereby increasing the light output degradation of the system over both the short and long term. The heat generation of the LED and thermal management of the LED have been studied extensively. Methods to effectively dissipate heat from the LEDs and maintain lower LED operating temperature are well understood. However, investigation of factors driving heat generation, the resulting temperature distribution in the phosphor layer, and the influence of the phosphor layer temperature on LED performance and reliability have not received the same focus. The goal of this dissertation was to understand the main factors driving heat and light generation and the transport of light and heat in the wavelength-converting layer of an LED system. Another goal was to understand the interaction between heat and light in the system and to develop and analyze a solution to reduce the wavelength-converting layer operating temperature, thereby improving light output and reliability. Even though past studies have explored generation and transfer separately for light and heat, to the best of the author's knowledge, this is the first study that has analyzed both factors simultaneously to optimize the performance of a phosphor-converted LED system, thus contributing new knowledge to the field. In this dissertation, a theoretical model was developed that modeled both light propagation and heat transfer in the wavelength-converting layer for identifying the factors influencing heat generation. This theoretical model included temperature-dependent phosphor efficiency and light absorption in the phosphor layer geometry. Experimental studies were used to validate the developed model. The model indicated good agreement with the experimental results. The developed theoretical model was then used to model experimental studies. These experiment results were compared with the model predicted results for total radiant power output of LED systems and phosphor layer surface temperature. These comparisons illustrated the effectiveness of a dedicated heat dissipation method in reducing the operating temperature of the wavelength-converting layer, and the contribution of different heat dissipation mechanisms were quantified using the developed numerical model. In addition to these short-term studies, an experiment was conducted to validate the effectiveness of the dedicated wavelength-converting heat sink design to improve system lifetime by reducing phosphor layer operating temperature. The proposed heat sink design decreased the operating temperature of the phosphor layer by ~10°C, improving lifetime by twofold. Finally, this dissertation investigated the potential of the developed theoretical model being used as a tool for prioritizing research tasks and as a design tool during the material selection and system configuration phases.

Active metamaterial: Gain and stability, and microfluidic chip for THz cell spectroscopy

NASA Astrophysics Data System (ADS)

Tang, Qi

Metamaterials are artificially designed composite materials which can exhibit unique and unusual properties such as the negative refractive index, negative phase velocity, etc. The concept of metamaterials becomes prevalent in the electromagnetic society since the first experimental implementation in the early 2000s. Many fascinated potential applications, e.g. super lens, invisibility cloaking, and novel antennas that are electrically small, have been proposed based on metamaterials. However, most of the applications still remain in theory and are not suitable for practical applications mainly due to the intrinsic loss and narrow bandwidth (large dispersion) determined by the fundamental physics of metamaterials. In this dissertation, we incorporate active gain devices into conventional passive metamaterials to overcome loss and even provide gain. Two types of active gain negative refractive index metamaterials are proposed, designed and experimentally demonstrated, including an active composite left-/right-handed transmission line and an active volumetric metamaterial. In addition, we investigate the non-Foster circuits for broadband matching of electrically small antennas. A rigorous way of analyzing the stability of non-Foster circuits by normalized determinant function is proposed. We study the practical factors that may affect the stability of non-Foster circuits, including the device parasitics, DC biasing, layouts and load impedance. A stable floating negative capacitor is designed, fabricated and tested. Moreover, it is important to resolve the sign of refractive index for active gain media which can be quite challenging. We investigate the analytical solution of a gain slab system, and apply the Nyquist criterion to analyze the stability of a causal gain medium. We then emphasize that the result of frequency domain simulation has to be treated with care. Lastly, this dissertation discusses another interesting topic about THz spectroscopy of live cells. THz spectroscopy becomes an emerging technique for studying the dynamics and interactions of cells and biomolecules, but many practical challenges still remain in experimental studies. We present a prototype of simple and inexpensive cell-trapping microfluidic chip for THz spectroscopic study of live cells. Cells are transported, trapped and concentrated into the THz exposure region by applying an AC bias signal while the chip maintains a steady temperature at 37 ?C by resistive heating. We conduct some preliminary experiments on E. coli and T cell solution and compare the transmission spectra of empty channels, channels filled with aqueous media only, and channels filled with aqueous medium with un-concentrated and concentrated cells.

Repertoire, Authenticity, and Instruction: The Presentation of American Indian Music in Oklahoma's Elementary Schools. Native Americans: Interdisciplinary Perspectives--A Garland Series.

ERIC Educational Resources Information Center

Damm, Robert J.

This book examines the presentation of American Indian music by elementary music educators in Oklahoma, which has the largest American Indian population of any state. A literature review covers an historical profile of multicultural music education, ethnomusicological studies of American Indian music, dissertations pertaining to American Indian…

Secure estimation, control and optimization of uncertain cyber-physical systems with applications to power networks

NASA Astrophysics Data System (ADS)

Taha, Ahmad Fayez

Transportation networks, wearable devices, energy systems, and the book you are reading now are all ubiquitous cyber-physical systems (CPS). These inherently uncertain systems combine physical phenomena with communication, data processing, control and optimization. Many CPSs are controlled and monitored by real-time control systems that use communication networks to transmit and receive data from systems modeled by physical processes. Existing studies have addressed a breadth of challenges related to the design of CPSs. However, there is a lack of studies on uncertain CPSs subject to dynamic unknown inputs and cyber-attacks---an artifact of the insertion of communication networks and the growing complexity of CPSs. The objective of this dissertation is to create secure, computational foundations for uncertain CPSs by establishing a framework to control, estimate and optimize the operation of these systems. With major emphasis on power networks, the dissertation deals with the design of secure computational methods for uncertain CPSs, focusing on three crucial issues---(1) cyber-security and risk-mitigation, (2) network-induced time-delays and perturbations and (3) the encompassed extreme time-scales. The dissertation consists of four parts. In the first part, we investigate dynamic state estimation (DSE) methods and rigorously examine the strengths and weaknesses of the proposed routines under dynamic attack-vectors and unknown inputs. In the second part, and utilizing high-frequency measurements in smart grids and the developed DSE methods in the first part, we present a risk mitigation strategy that minimizes the encountered threat levels, while ensuring the continual observability of the system through available, safe measurements. The developed methods in the first two parts rely on the assumption that the uncertain CPS is not experiencing time-delays, an assumption that might fail under certain conditions. To overcome this challenge, networked unknown input observers---observers/estimators for uncertain CPSs---are designed such that the effect of time-delays and cyber-induced perturbations are minimized, enabling secure DSE and risk mitigation in the first two parts. The final part deals with the extreme time-scales encompassed in CPSs, generally, and smart grids, specifically. Operational decisions for long time-scales can adversely affect the security of CPSs for faster time-scales. We present a model that jointly describes steady-state operation and transient stability by combining convex optimal power flow with semidefinite programming formulations of an optimal control problem. This approach can be jointly utilized with the aforementioned parts of the dissertation work, considering time-delays and DSE. The research contributions of this dissertation furnish CPS stakeholders with insights on the design and operation of uncertain CPSs, whilst guaranteeing the system's real-time safety. Finally, although many of the results of this dissertation are tailored to power systems, the results are general enough to be applied for a variety of uncertain CPSs.

Drama and Oral Interpretation: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1978 (Vol. 38 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 16 titles deal with the following topics: an examination of inexperienced actors performing the plays of William Shakespeare; an investigation of the philosophies and practices of a summer theatre producer and manager; the…

Theatre and Oral Interpretation: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1982 (Vol. 42 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 25 titles deal with a variety of topics, including the following: (1) the development of American theatre management practices between 1830 and 1896; (2) the aesthetics of audience response; (3) P. Picasso as a theatrical…

Rhetorical and Communication Theory: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1980 (Vol. 41 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The ten titles deal with the following topics: (1) rhetorical theories for college writing teachers, (2) contemporary rhetorical criticism of literary art, (3) the rhetoric of the new religious cults, (4) Victorian argument, (5)…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1984 (Vol. 45 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 37 titles deal with a variety of topics, including the following: (1) the role of television in the lives of older homebound individuals; (2) radio wars between Cuba and the United States; (3) the relationship between…

Written Language and Writing Abilities: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1981 (Vol. 42 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 29 titles deal with a vareity of topics, including the following: (1) the interrelationship of reading and writing in the composing process; (2) the relationship between composition teachers' ability to write and the writing…

Interpersonal, Nonverbal, and Small Group Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984, (Vol. 44 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 12 titles deal with the following topics: (1) communication style in initial meetings of small groups; (2) gender orientation, communicative competency, and communication satisfaction in acquaintance dyads; (3) attitudinal,…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1981 (Vol. 42 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 50 titles deal with a variety of topics, including the following: (1) a history of broadcast audience research in the United States from 1920 to 1980; (2) factors contributing to the believability of television newscasters; (3)…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1981 (Vol. 41 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 47 titles deal with a variety of topics, including the following: (1) the effect of source variation upon children's reactions to television commercials; (2) covert observation as a means of measuring the affective states of…

Interpersonal, Nonverbal, and Small Group Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1979 (Vol. 39 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 19 titles deal with a variety of topics, including the following: group communication; effects of communication skills training on marital interaction; relationship among assertiveness, manifest anxiety, and self-esteem; dyadic…

Interpersonal, Nonverbal, and Small Group Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1985 (Vol. 46 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 18 titles deal with a variety of topics, including the following: (1) ways of conceptualizing and evaluating group discussion; (2) participant observations of communication themes in families facing death; (3) perceptions of…

Theatre and Oral Interpretation: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July 1979 through June 1980 (Vol. 40 Nos. 1 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 titles deal with the following topics: (1) a taxonomy of educational objectives in acting; (2) contemporary musical theatre in Utah; (3) applying management concepts to educational theatre operations; (4) creative drama and…

Interpersonal, Nonverbal, and Small Group Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1983 (Vol. 44 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 titles deal with the following topics: (1) the development of a module to attain the leadership competency of encouraging improved interpersonal communication through feedback; (2) communicating in an American Taoist…

Interpersonal, Nonverbal, and Small Group Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1982 (Vol. 43 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 20 titles discuss a variety of topics, including the following: (1) caregiver talk to toddlers in dyadic and polyadic care; (2) communication tactics for neutralizing verbal aggression; (3) physical attractiveness and nonverbal…

Part four: The research dissertation: planning, producing and writing a thesis.

PubMed

Quick, J; Hall, S

2015-11-01

Dissertations have become common inclusions to postgraduate degrees in healthcare. To the novice researcher, undertaking an extensive project of this kind can appear daunting. In this final article in the series 'Spotlight on Research', Julie Quick and Susan Hall advise perioperative practitioners on how to plan, produce and write a research dissertation. Guidance is also given on disseminating the results from research studies.

End-to-End Fault Tolerance Using Transport Layer Multihoming

DTIC Science & Technology

2005-01-01

it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor of Philosophy...dissertation and that in my opinion it meets the academic and professional standard required by the University as a dissertation for the degree of Doctor...grow tired of revising the same text over and over, he always showed enthusiasm for helping me improve its

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," April through June 1978 (Vol. 38, Nos. 10 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 17 titles deal with the following topics: the effects of preinstructional activities on the learning and retention of prose; the interaction of picture and print in reading instruction; the perception of structure in scrambled…

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1979 (Vol. 39 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 21 titles deal with a variety of topics, including the following: children's development of syntactic aspects of reading comprehension, the relative contributions of the individual and the text in the comprehension and retention…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1985 (Vol. 45 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 45 titles deal with a variety of topics, including the following: (1) gender portrayal in magazine advertising; (2) the role of special interest groups in agenda-setting; (3) the relationship between sensation-seeking and horror…

Teaching of Writing: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984, (Vol. 44 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 38 titles deal with a variety of topics, including the following: (1) revision using electronic word processing; (2) photography as an intervention strategy in the verbal composing process; (3) the effects of planning processes…

Applied Communication, Argumentation, and Debate: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1982 (Vol. 42 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 11 titles deal with the following topics: (1) interpersonal communication in the reference interview; (2) the relationship of a principal's communication behavior to the teacher's perceived job satisfaction; (3) the relationship…

Rhetoric and Public Address: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1980 (Vol. 40 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 20 titles deal with a variety of topics, including the following: (1) the campaign communication during the Carter-Ford television debates; (2) apprehensiveness and performance in public speaking; (3) a history and criticism of…

Theatre and Oral Interpretation: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1982 (Vol. 43 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 16 titles deal with the following topics: (1) children's theatre activities at Karamu House in Cleveland, Ohio; (2) the development, implementation, and significance of story theatre as a theatrical art form and performance…

An Overview of Theses and Dissertations Completed in Family and Consumer Sciences: 1999. [and] A Listing of Theses and Dissertations Completed in Family and Consumer Sciences: 1999.

ERIC Educational Resources Information Center

Kennemer, Cathy G.; Ownbey, Shiretta F.

2000-01-01

Summarizes 433 family and consumer sciences theses and 221 dissertations by institution and subject and compares 1995-1999. Lists authors and titles by subject: art/design, child development, clothing/apparel, family/consumer resource management, family and consumer sciences, family relations, foods, human environment/housing, hotel/restaurant…

An Overview of the Theses and Dissertations Completed in Family and Consumer Sciences: 2000. [and] A Listing of Theses and Dissertations Completed in Family and Consumer Sciences: 2000.

ERIC Educational Resources Information Center

Smith, Terra L.; Barron-Krog, Jennifer; Fullerton, Angela R.

2001-01-01

Tables categorize 635 family and consumer sciences theses and dissertations by institution and subject. The list of titles is categorized as follows: art and design, child development, clothing/apparel, communications, family and consumer sciences, family relations, resource management, foods, human environment/housing, hotel/restaurant…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1980 (Vol. 41 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 47 titles deal with a variety of topics, including the following: (1) television and attitudes about crime, (2) attitude measurement in marketing communications, (3) soap operas and liberal education values, (4) the existence of…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1980 (Vol. 40 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 55 titles deal with a variety of topics, including the following: (1) the prime time access rule; (2) media education; (3) magazine and children's advertising; (4) Irish national and Third World cinema; (5) international radio…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through October 1978 (Vol. 38 No. 7 through Vol. 39 No. 4).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 14 titles deal with the following topics: written communication flow between administrators and faculty at a community college; an analysis of the perceptions of legislators and university administrators on selected issues;…

Mass Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984, (Vol. 44 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 36 titles deal with a variety of topics, including the following: (1) content diversity in local television news; (2) advertising influences on consumers' use of evidence; (3) organized labor and the mass media; (4) feminist film…

Speech Communication and Communication Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through September 1977 (Vol. 38 Nos. 1 through 3).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 22 titles deal with a variety of topics, including the following: the rhetorical effectiveness of Senator Edmund S. Muskie's 1972 Presidential primary election campaign; persuasive speaking techniques of black college and…

Language Use, Language Ability, and Language Development: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1977 (Vol. 38 No. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 27 titles deal with a variety of topics, including the following: facilitation of language development in disadvantaged preschool children; auditory-visual discrimination skills, language performance, and development of manual…

Journalism and Journalism Education: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1979 (Vol. 40 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 12 titles deal with the following topics: establishing newspapers in the Washington Territory; the business history of the antebellum Wisconsin newspaper, 1833-1860; the idea of news in a culturally plural society; the…

Interpersonal, Nonverbal, and Small Group Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1981 (Vol. 41 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 14 titles deal with the following topics: (1) the relationships between power, gender, and mode of conflict management in superior/subordinate relationships; (2) the interaction processes of groups with varying levels of…

Business and Organizational Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1982 (Vol. 43 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 16 titles deal with a variety of topics, including the following: (1) the delivery of bad news in organizations; (2) the diffusion of judicial innovations; (3) speech action in organizational socialization; (4) differential…

Written Language and Writing Abilities: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984, (Vol. 44 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 33 titles deal with a variety of topics, including the following: (1) children's sense of audience; (2) rhetorical foundations of technical communication; (3) sources of negative attitudes toward writing; (4) the development of…

Rhetoric and Public Address: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1984 (Vol. 45 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 10 titles deal with the following topics: (1) the television sermons of Jerry Falwell, W. A. Criswell, Robert Schuller, Jimmy Swaggert, James Robinson, and Howard Estep; (2) the preaching of Wallace E. Fisher; (3) Theodore…

Rhetoric and Public Address: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1982 (Vol. 42 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 14 titles deal with the following topics: (1) the rhetoric of British Prime Minister Margaret Thatcher; (2) the rhetorical strategies employed in the political speaking of George C. Wallace in the 1968 United States presidential…

Rhetorical and Communication Theory: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1982 (Vol. 42 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 18 titles deal with the following topics: (1) the rhetorical theory and practice of Walter Lippmann; (2) communication, "root-metaphor" orientation, and decision making; (3) teaching as rhetoric; (4) the conditions and…

Interpersonal, Nonverbal, and Small Group Communication: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1979 (Vol. 40 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 24 titles deal with a variety of topics, including the following: a social skills training program; facial kinesic correlates of terminal cancer patients; the relationships among indices of social cognition, motivation, and…

Rhetorical and Communication Theory: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July 1979 through June 1980 (Vol. 40 Nos. 1 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 16 titles deal with the following topics: (1) the philosophy of rhetoric; (2) an analytical study of the development of major concepts of causality in philosophy; (3) an ontological approach to interpersonal communication…

The Implications of a Decade of Diversity-Related Doctoral Dissertations (2000-2009) in LIS: Supporting Inclusive Library Practices

ERIC Educational Resources Information Center

Subramaniam, Mega M.; Rodriguez-Mori, Howard; Jaeger, Paul T.; Hill, Renee Franklin

2012-01-01

This article reports the findings of a study exploring the nature and extent of research on diversity in library and information science (LIS) doctoral dissertations from 2000 to 2009. By systematically examining the last decade of dissertations in the field, this study is meant to reveal the levels of interest in diversity research among doctoral…

Journalism and Journalism Education: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," March through December 1977 (Vol. 37 No. 9 through Vol. 38 No. 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 18 titles deal with a variety of journalism-related topics, including the following: the needs of community newspapers; factors affecting reader evaluation of authors; reader differentiation between news stories and editorials;…

Reading Instruction: Remedial and Compensatory: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1977 (Vol. 38 Nos. 1 through 6), Part One.

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 titles deal with the following topics: the relationship of racial integration, auditory discrimination training, and other factors to reading achievement; the relative effectiveness of the controlled reader and the speech…

Written Language and Writing Abilities: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July 1979 through June 1980 (Vol. 40 Nos. 1 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 21 titles deal with the following topics: (1) the adolescent writer's developing sense of audience; (2) the entry skills, methods, and attitudes of intermediate composition students in postsecondary composition programs; (3)…

Speech Communication Education and Classroom Interaction: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984 (Vol. 44 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 10 titles deal with the following topics: (1) communication training for adolescents and their teachers; (2) faculty career paths in speech communication; (3) student self-concept modification in communication courses; (4)…

Applied Communication, Argumentation, and Debate: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1985 (Vol. 46 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 21 titles deal with a variety of topics, including the following: (1) comparison of receiver profiles in Clark County, Nevada, for various school-community relations communications channels; (2) effects of profit knowledge, size…

Reading Instruction: Preschool and Elementary: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," October through December 1978 (Vol. 39 Nos. 4 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 23 titles deal with a variety of topics, including the following: relationships among attitudes, intelligence, and reading achievement; the purposes and processes of reading as described by elementary school children; evaluating…

Rhetorical and Communication Theory: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1981 (Vol. 41 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The nine titles deal with the following topics: (1) the theory and application of presumption in public debate; (2) the rhetoric of transcendentalism; (3) speechwriting in rhetorical criticism; (4) the conspiracy argument as…

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1980 (Vol. 40 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 23 titles deal with a variety of topics, including the following: (1) the effects on reading comprehension of a number of reader-related factors, including lookback during studying, oral versus silent reading modes, reading…

Reading, Comprehension, and Memory Processes: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1980 (Vol. 41 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 31 titles deal with a variety of topics, including the following: (1) teaching strategies for reading comprehension; (2) strategies for assigning meaning to unfamiliar words in context; (3) differential processing of explicit and…

Reading Instruction: Preschool and Elementary: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through September 1978 (Vol. 39 Nos. 1 through 3).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 25 titles deal with a variety of topics, including the following: learning outcomes produced by single- and multi-grade primary classrooms; the effect of sex-role stereotyped picture books on children's behavior; word recognition…

Language Use, Language Ability, and Language Development: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1979 (Vol. 39 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 23 titles deal with the following topics: sex appropriate and sex inappropriate language; lexical retrieval and perceptual errors; naming deficits in anomia and aphasia; developmental discourse; pragmatic information and…

Speech Communication Education and Classroom Instruction: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1982 (Vol. 43 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The eight titles deal with the following topics: (1) the effects of self-instructional and discrimination communication training on the development of confrontation skills in prepracticum counseling trainees, (2) cross-cultural…

Rhetoric and Public Address: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1983 (Vol. 43 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 31 titles deal with a variety of topics, including the following: (1) the rhetoric of confrontation in Northern Ireland; (2) rhetorical arguments in public health regulations; (3) epideictic discourse in the founding of the…

Rhetorical and Communication Theory: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1979 (Vol. 39 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 13 titles deal with the following topics: confessional rhetoric in the poetry of Anne Sexton, rhetorical criticism, the Hippocratic oath, messages communicated through team sports as a medium of social interaction, the silent…

Reading Instruction: Secondary: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," March through December 1977 (Vol. 37 No. 9 through Vol. 38, No. 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 11 titles deal with the following topics: secondary school principals' attitudes toward characteristics of an ideal reading program; the effects of rock music on the reading comprehension of eighth grade students; objectives for…

Rhetorical and Communication Theory: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984, (Vol. 44 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a series providing continuing information on recent doctoral dissertations. The 23 titles deal with a variety of topics, including the following: (1) the rhetoric of scientific controversy; (2) Erving Goffman's interactional theory of communication conduct; (3) a phenomenology of feminism; (4) a…

High temperature structural sandwich panels

NASA Astrophysics Data System (ADS)

Papakonstantinou, Christos G.

High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several hundred degrees Centigrade. Hence the material has excellent potential for various types of applications. The analytical predictions from both models provide reasonably accurate results. Glass, AR-glass, carbon and Nicalon tows and carbon fabrics could be successfully used as skin reinforcements increasing the flexural stiffness and strength of the core. No occurrence of fiber delamination was observed.

Theoretical and experimental study of low-finesse extrinsic Fabry-Perot interferometric fiber optic sensors

NASA Astrophysics Data System (ADS)

Han, Ming

In this dissertation, detailed and systematic theoretical and experimental study of low-finesse extrinsic Fabry-Perot interferometric (EFPI) fiber optic sensors together with their signal processing methods for white-light systems are presented. The work aims to provide a better understanding of the operational principle of EFPI fiber optic sensors, and is useful and important in the design, optimization, fabrication and application of single mode fiber(SMF) EFPI (SMF-EFPI) and multimode fiber (MMF) EFPI (MMF-EFPI) sensor systems. The cases for SMF-EFPI and MMF-EFPI sensors are separately considered. In the analysis of SMF-EFPI sensors, the light transmitted in the fiber is approximated by a Gaussian beam and the obtained spectral transfer function of the sensors includes an extra phase shift due to the light coupling in the fiber end-face. This extra phase shift has not been addressed by previous researchers and is of great importance for high accuracy and high resolution signal processing of white-light SMF-EFPI systems. Fringe visibility degradation due to gap-length increase and sensor imperfections is studied. The results indicate that the fringe visibility of a SMF-EFPI sensor is relatively insensitive to the gap-length change and sensor imperfections. Based on the spectral fringe pattern predicated by the theory of SMF-EFPI sensors, a novel curve fitting signal processing method (Type 1 curve-fitting method) is presented for white-light SMF-EFPI sensor systems. Other spectral domain signal processing methods including the wavelength-tracking, the Type 2-3 curve fitting, Fourier transform, and two-point interrogation methods are reviewed and systematically analyzed. Experiments were carried out to compare the performances of these signal processing methods. The results have shown that the Type 1 curve fitting method achieves high accuracy, high resolution, large dynamic range, and the capability of absolute measurement at the same time, while others either have less resolution, or are not capable of absolute measurement. Previous mathematical models for MMF-EFPI sensors are all based on geometric optics; therefore their applications have many limitations. In this dissertation, a modal theory is developed that can be used in any situations and is more accurate. The mathematical description of the spectral fringes of MMF-EFPI sensors is obtained by the modal theory. Effect on the fringe visibility of system parameters, including the sensor head structure, the fiber parameters, and the mode power distribution in the MMF of the MMF-EFPI sensors, is analyzed. Experiments were carried out to validate the theory. Fundamental mechanism that causes the degradation of the fringe visibility in MMF-EFPI sensors are revealed. It is shown that, in some situations at which the fringe visibility is important and difficult to achieve, a simple method of launching the light into the MMF-EFPI sensor system from the output of a SMF could be used to improve the fringe visibility and to ease the fabrication difficulties of MMF-EFPI sensors. Signal processing methods that are well-understood in white-light SMF-EFPI sensor systems may exhibit new aspects when they are applied to white-light MMF-EFPI sensor systems. This dissertation reveals that the variations of mode power distribution (MPD) in the MMF could cause phase variations of the spectral fringes from a MMF-EFPI sensor and introduce measurement errors for a signal processing method in which the phase information is used. This MPD effect on the wavelength-tracking method in white-light MMF-EFPI sensors is theoretically analyzed. The fringe phases changes caused by MPD variations were experimentally observed and thus the MFD effect is validated.

Learning [Voice

ERIC Educational Resources Information Center

Tauberer, Joshua Ian

2010-01-01

The [voice] distinction between homorganic stops and fricatives is made by a number of acoustic correlates including voicing, segment duration, and preceding vowel duration. The present work looks at [voice] from a number of multidimensional perspectives. This dissertation's focus is a corpus study of the phonetic realization of [voice] in two…

Student Discipline Strategies: Practitioner Perspectives

ERIC Educational Resources Information Center

Mancini, Joseph A.

2017-01-01

This applied dissertation presented a mixed method design to gain a broader perspective of the perceptions of classroom management practitioners within a particular school district. Many teachers, or practitioners, experience issues with classroom management because of their understanding of strategies they use. Because of the researcher's…

Language Nests and Language Acquisition: An Empirical Analysis

ERIC Educational Resources Information Center

Okura, Eve K.

2017-01-01

This dissertation presents the findings from interviews conducted with language nest workers, teachers, language nest coordinators, administrators of language revitalization programs, principals and directors of language immersion schools that work in close proximity with language nests, and linguists involved in language revitalization efforts.…

The Literacy Practices of Law Enforcement

ERIC Educational Resources Information Center

Seawright, Leslie

2012-01-01

This dissertation investigates police report writing at the Jackson Police Department in Northwest Arkansas. It presents three primary research questions which are addressed through qualitative methods of interview, observation, and discourse analysis: (1) In what ways does police training address report writing?; (2) What audience awareness do…

Preservice Teacher Talk Surrounding Gender

ERIC Educational Resources Information Center

Engebretson, Kathryn Ellerhoff

2012-01-01

This dissertation examines the discourses around gender present among a cohort of preservice secondary social studies teachers (n = 25) and how gender discourses manifested throughout their preparatory year with particular interest paid to their thoughts about curricula, schools, and students. Using ethnographic study design, the author presents…

Accessing Electronic Theses: Progress?

ERIC Educational Resources Information Center

Tennant, Roy

2000-01-01

Describes various ways by which universities provide access to their electronic theses and dissertations (ETDs), discussing UMI (University Microfilms International), XML (eXtensible Markup Language), and other formats. Discusses key leaders--national and international--in the ETD effort. Outlines the two main methods for locating ETDs. Presents a…

A Grammar of Kurtop

ERIC Educational Resources Information Center

Hyslop, Gwendolyn

2011-01-01

Kurtop is a Tibeto-Burman language spoken by approximately 15,000 people in Northeastern Bhutan. This dissertation is the first descriptive grammar of the language, based on extensive fieldwork and community-driven language documentation in Bhutan. When possible, analyses are presented in typological and historical/comparative perspectives and…

Phonation Types in Marathi: An Acoustic Investigation

ERIC Educational Resources Information Center

Berkson, Kelly Harper

2013-01-01

This dissertation presents a comprehensive instrumental acoustic analysis of phonation type distinctions in Marathi, an Indic language with numerous breathy voiced sonorants and obstruents. Important new facts about breathy voiced sonorants, which are crosslinguistically rare, are established: male and female speakers cue breathy phonation in…

Education in Latin America: A Selected Bibliography (1986-1995).

ERIC Educational Resources Information Center

Aedo-Richmond, Ruth

1996-01-01

Presents a selected bibliography of books, theses, articles, and dissertations concerning education in Latin America. Includes separate sections on Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Peru, Uruguay, and Venezuela. All selections are in…

Creating wavelet-based models for real-time synthesis of perceptually convincing environmental sounds

NASA Astrophysics Data System (ADS)

Miner, Nadine Elizabeth

1998-09-01

This dissertation presents a new wavelet-based method for synthesizing perceptually convincing, dynamic sounds using parameterized sound models. The sound synthesis method is applicable to a variety of applications including Virtual Reality (VR), multi-media, entertainment, and the World Wide Web (WWW). A unique contribution of this research is the modeling of the stochastic, or non-pitched, sound components. This stochastic-based modeling approach leads to perceptually compelling sound synthesis. Two preliminary studies conducted provide data on multi-sensory interaction and audio-visual synchronization timing. These results contributed to the design of the new sound synthesis method. The method uses a four-phase development process, including analysis, parameterization, synthesis and validation, to create the wavelet-based sound models. A patent is pending for this dynamic sound synthesis method, which provides perceptually-realistic, real-time sound generation. This dissertation also presents a battery of perceptual experiments developed to verify the sound synthesis results. These experiments are applicable for validation of any sound synthesis technique.

Multi-scale cell/surface interaction on modified titanium aluminum vanadium surfaces

NASA Astrophysics Data System (ADS)

Chen, Jianbo

This dissertation presents a series of experimental studies of the effects of multi-scale cell/surface interactions on modified Ti-6Al-4V surfaces. These include laser-grooved surfaces; porous structures and RGD-coated laser-grooved surfaces. A nano-second DPSS UV lasers with a Gaussian pulse energy profile was used to introduce the desired micro-groove geometries onto Ti-6Al-4V surfaces. This was done without inducing micro-cracks or significant changes in surface chemistry within the heat affected zones. The desired 8-12 mum groove depths and widths were achieved by the control of pulse frequency, scan speed, and the lens focal length that controls spot size. The interactions between human osteosarcoma (HOS) cells and laser-grooved Ti-6Al-4V surfaces were investigated after 48 hours of cell culture. The cell behavior, including cell spreading, alignment and adhesion, was elucidated using scanning electronic microscopy (SEM), immuno-fluorescence staining and enzymatic detachment. Contact guidance was shown to increase as grooved spacing decreased. For the range of micro-groove geometries studied, micro-grooves with groove spacings of 20 mum provided the best combination of cell orientation and adhesion. Short-term adhesion experiments (15 mins to 1 day) also revealed that there is a positive correlation between cell orientation and cell adhesion. Contact guidance on the micro-grooved surfaces is shown to be enhanced by nano- and micro-scale asperities that provide sites for the attachment of lamellopodia during cell locomotion and spreading. Contact guidance is also promoted by the geometrical confinement provided by laser grooves. An experimental study of initial cell spreading and ingrowth into Ti-6Al-4V porous structures was also carried out on porous structures with different pore sizes and geometries. A combination of SEM, the tetrazolium salt (MTT) colorimetric assay and enzymatic detachment were used to study cell spreading and adhesion. The extent of cell ingrowth, pore coverage, cell adhesion and proliferation was observed to increase with decreasing pore size. It was found that fiber geometries provided guidance for cell spreading along the fiber directions. However, the larger gaps in fiber geometries made pore bridging difficult. Finally, this dissertation presents an in vivo study of the combined effects of laser microgrooving and RGD-coating on the osseointegration of implanted Ti-6Al-4V pins. Both histological and biomechanical results show that the combination of laser microgrooving and RGD-coating results in improved osseointegration over the control surfaces. All the above findings have important implications for future orthopedic and dental implant design.

Digital signal processing techniques for coherent optical communication

NASA Astrophysics Data System (ADS)

Goldfarb, Gilad

Coherent detection with subsequent digital signal processing (DSP) is developed, analyzed theoretically and numerically and experimentally demonstrated in various fiber-optic transmission scenarios. The use of DSP in conjunction with coherent detection unleashes the benefits of coherent detection which rely on the preservaton of full information of the incoming field. These benefits include high receiver sensitivity, the ability to achieve high spectral-efficiency and the use of advanced modulation formats. With the immense advancements in DSP speeds, many of the problems hindering the use of coherent detection in optical transmission systems have been eliminated. Most notably, DSP alleviates the need for hardware phase-locking and polarization tracking, which can now be achieved in the digital domain. The complexity previously associated with coherent detection is hence significantly diminished and coherent detection is once gain considered a feasible detection alternative. In this thesis, several aspects of coherent detection (with or without subsequent DSP) are addressed. Coherent detection is presented as a means to extend the dispersion limit of a duobinary signal using an analog decision-directed phase-lock loop. Analytical bit-error ratio estimation for quadrature phase-shift keying signals is derived. To validate the promise for high spectral efficiency, the orthogonal-wavelength-division multiplexing scheme is suggested. In this scheme the WDM channels are spaced at the symbol rate, thus achieving the spectral efficiency limit. Theory, simulation and experimental results demonstrate the feasibility of this approach. Infinite impulse response filtering is shown to be an efficient alternative to finite impulse response filtering for chromatic dispersion compensation. Theory, design considerations, simulation and experimental results relating to this topic are presented. Interaction between fiber dispersion and nonlinearity remains the last major challenge deterministic effects pose for long-haul optical data transmission. Experimental results which demonstrate the possibility to digitally mitigate both dispersion and nonlinearity are presented. Impairment compensation is achieved using backward propagation by implementing the split-step method. Efficient realizations of the dispersion compensation operator used in this implementation are considered. Infinite-impulse response and wavelet-based filtering are both investigated as a means to reduce the required computational load associated with signal backward-propagation. Possible future research directions conclude this dissertation.

An Experimental Investigation on the Static Equilibria and Dynamics of Liquid Bridges. Degree Awarded by the University of Alabama, 1997

NASA Technical Reports Server (NTRS)

Resnick, Andrew Howard

1997-01-01

A liquid bridge is a volume of liquid held between two or more solid supports. In the case of small disk supports with a sharp edge, the contact line between the bridge and the support disk will be anchored along the edge of the disk. For these cases the solid presents a geometrical singularity and the contact angle is indeterminate within a given range. This dissertation presents research conducted on liquid bridges with anchored contact lines. The three major topics covered are: determining the role of support geometry on static equilibria, liquid bridge dynamical behavior, and forces exerted by a liquid bridge on a support structure. The work was primarily experimental and conducted in a "Plateau tank" that allowed for the simulation of equivalent low-gravity conditions. The main thrust of the experimental work involved the use of a high resolution optical measurement system for imaging the dynamic zone shape, measurement of the static and dynamic contact angles and non-invasive analysis of excited surface modes. The liquid bridge was manipulated by computer controlled linear actuators which allowed precise control over the physical characteristics of the bridge. Experiments have been carried out to locate a bifurcation point along the maximum volume axisymmetric stability margin. Below the critical slenderness the bifurcation from an axisymmetric to a stable nonaxisymmetric configuration is supercritical. However, above this critical slenderness, the bifurcation is subcritical. A series of experiments analyzed the effect on axisymmetric bridge stability by using support disks of different radii, The shape behavior as transition points were approached, as well as the limiting case of a vanishing support radius was investigated. Experiments were performed to determine the resonant frequencies of axisymmetric bridges subject to lateral vibrations. Anomolous results led to a series of experiments to characterize nonlinearities present in the dynamic bridge shape. Finally, an attempt was made to experimentally measure the force exerted by the bridge on the lower support disk. This was done through use of a force balance apparatus. Particular attention was paid to the behavior of the bridge as the minimum volume stability limit was approached.

Aspects of baryon structure in lattice QCD

NASA Astrophysics Data System (ADS)

Babich, Ronald

Despite the long success of Quantum Chromodynamics (QCD) as the theory of the strong interactions, there remains much to be understood about the structure of hadrons and the consequences of QCD in the nonperturbative regime. Lattice gauge theory, a framework nearly as old as QCD itself, makes calculations in this regime possible, starting from first principles. With advances in theoretical understanding, methods, and computer technology, the lattice has found application to an ever-widening range of problems. In this dissertation, I consider two such problems having to do with the structure of baryons. The first concerns the contribution of sea quarks, and the strange quark in particular, to form factors of the nucleon. This has been a long-standing challenge for the lattice, because such contributions involve the insertion of a current on a quark loop, demanding the full inversion of the discretized Dirac operator, conceptually a large sparse matrix. I discuss methods for addressing this challenge and present a calculation of the strange scalar form factor and the related parameter fTs. The latter is of great theoretical interest, since it enters into the cross section for the scattering of dark matter off nuclei in supersymmetric extensions of the standard model. As such, it represents a major uncertainty in the interpretation of direct detection experiments. I also present results for the strange quark contribution to the nucleon's axial and electromagnetic form factors, which are themselves the subject of active experimental programs. These calculations were performed using the Wilson fermion formulation on a 243 x 64 anisotropic lattice. In the second part of the dissertation, I turn to the valence sector and address the role of diquark correlations in the observed spectrum of hadrons and their properties. A diquark is a correlated pair of quarks, thought to play an important role in certain phenomenological models of hadrons. I present results for baryon wave functions, evaluated in both the Coulomb and Landau gauges. By comparing baryons that differ in their diquark content, I find evidence for enhanced correlation in the scalar diquark channel, as favored by QCD-inspired quark models. I also present results for diquark mass splittings, determined from diquark correlators in the Landau gauge. This second set of calculations was performed with the overlap Dirac operator on quenched gauge configurations at beta = 6.

On program restructuring, scheduling, and communication for parallel processor systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polychronopoulos, Constantine D.

1986-08-01

This dissertation discusses several software and hardware aspects of program execution on large-scale, high-performance parallel processor systems. The issues covered are program restructuring, partitioning, scheduling and interprocessor communication, synchronization, and hardware design issues of specialized units. All this work was performed focusing on a single goal: to maximize program speedup, or equivalently, to minimize parallel execution time. Parafrase, a Fortran restructuring compiler was used to transform programs in a parallel form and conduct experiments. Two new program restructuring techniques are presented, loop coalescing and subscript blocking. Compile-time and run-time scheduling schemes are covered extensively. Depending on the program construct, thesemore » algorithms generate optimal or near-optimal schedules. For the case of arbitrarily nested hybrid loops, two optimal scheduling algorithms for dynamic and static scheduling are presented. Simulation results are given for a new dynamic scheduling algorithm. The performance of this algorithm is compared to that of self-scheduling. Techniques for program partitioning and minimization of interprocessor communication for idealized program models and for real Fortran programs are also discussed. The close relationship between scheduling, interprocessor communication, and synchronization becomes apparent at several points in this work. Finally, the impact of various types of overhead on program speedup and experimental results are presented.« less

Charmed and strange baryon production in 29 GeV electron positron annihilation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, S.R.

This dissertation presents measurements of the production rates of baryons with different strangeness and spin. The analyses presented here use data taken with the Mark III detector at the PEP storage ring, operating at a center of mass energy of 29 GeV. The ..xi../sup /minus// production rate is measured to be 0.017 +- 0.004 +- 0.004 per hadronic event, ..cap omega../sup /minus// production is measured to be 0.014 +- 0.006 +- 0.004 per hadronic event, and ..xi..*/sup 0/ production is less than 0.006 per hadronic event at a 90% confidence level. These measurements place strong constraints on models of baryonmore » production. In particular, the unexpectedly high rate of ..cap omega../sup /minus// production is difficult to explain in any diquark based model. Semileptonic ..lambda../sub c//sup +/ decays have also been observed. Because neither the branching ratios nor the production rate are well known, it is difficult to interpret these results. However, they do indicate that the branching ratio for ..lambda../sub c//sup +/ ..-->.. ..lambda..l..nu.. may be higher than previous experimental measurements. 85 refs., 45 figs., 12 tabs.« less

Dielectric micro-resonator-based opto-mechanical systems for sensing applications

NASA Astrophysics Data System (ADS)

Ali, Amir Roushdy

In recent years, whispering gallery mode (WGM), or morphology dependent optical resonances (MDR) of dielectric micro-resonators have attracted interest with proposed applications in a wide range of areas due to the high optical quality factors, Q, they can exhibit (reaching ~ 10. 9 for silica spheres). Micro-resonator WGMs have been used in applications that include those in spectroscopy, micro-cavity laser technology, optical communications (switching, filtering and multiplexing), sensors technologies and even chemical and biological sensing. The WGM of these dielectric micro-resonators are highly sensitive to morphological changes (such as the size, shape, or refractive index) of the resonance cavity and hence, can be tuned by causing a minute change in the physical condition of the surrounding. In this dissertation, we have been creating opto-mechanical systems, which at their most basic, are extraordinarily sensitive sensors. One of the ultimate goals of this dissertation is to develop sensors capable of detecting the extremely small electric field changes. To improve the performance of the sensors, we couple a polymer cantilever beam to a dielectric micro-resonator. The eventual use of such ultra sensitive electric filed sensors could include neural-machine interfaces for advanced prosthetics devices. The work presented here includes a basic analysis and experimental investigations of the electric field sensitivity and range of micro-resonators of several different materials and geometries followed by the electric field sensor design, testing, and characterization. Also, the effects of angular velocity on the WGM shifts of spherical micro-resonators are also investigated. The elastic deformation that is induced on a spinning resonator due to the centrifugal force may lead to a sufficient shift in the optical resonances and therefore interfering with its desirable operational sensor design. Furthermore, this principle could be used for the development of angular speed detection photonic sensors. In previous applications, the WGM shifts induced by the external effects were monitored by identifying and tracking individual resonance dip in the optical transmission spectrum. The success of the WGM sensors is strongly dependent on the precise and speeds tracking of the shifts of the resonant wavelengths. In this dissertation, we demonstrate the application of WGM micro-resonators for high-speed transient sensing (wide-bandwidth). To facilitate the use of the sensors for high-speed transient applications, we tune the interrogation laser using a harmonic rather than a ramp waveform and calibrate the laser response at various input frequencies and amplitudes using a Fabry-Perot interferometer. WGM shifts are tracked using a fast cross-correlation algorithm on the transmission spectra. We demonstrate dynamic force measurements up to 10 kHz using this approach. We also present a simple lumped-heat capacity thermal model to predict the laser's tuning response.

Micro and Nano Electromechanical Systems for Near-Zero Power Infrared Detection

NASA Astrophysics Data System (ADS)

Qian, Zhenyun

Light is one of the most important tools for human beings to probe and sense the physical world. Infrared (IR) radiation located in longer wavelengths than those of visible light carries rich information of an environment as it reveals the temperature distribution and chemical composition of objects. In addition, it has been utilized for communication and distance measurement owing to the atmospheric window and insensitiveness of human eyes to the IR radiation. As a result, IR detectors nowadays can be found in a wide variety of applications, including thermal imaging, automotive night vision, standoff chemical detection, remote control and laser ranging, just to mention a few. On the other hand, due to the recent fast development of the Internet of Things (IoT), there is a growing demand for miniaturized and power efficient unattended sensors that can be widely distributed in large volumes to form a wireless sensor networks capable of monitoring the environment with high accuracy and long lifetime. In this context, micro and nano electromechanical systems (MEMS/NEMS) may provide a huge impact, since they can be used for the implementation of miniaturized, low power, high-performance sensors and wireless communication devices fully compatible with standard integrated circuitry. This dissertation presents the design and the experimental verification of high performance uncooled IR detectors based on Aluminum Nitride (AlN) nano electromechanical resonators, and a first-of-its-kind near-zero power IR digitizer based on plasmonically-enhanced micromechanical photoswitches. The unique advantages of the piezoelectric AlN thin film in terms of scaling in thickness and transduction efficiency are exploited by the first experimental demonstration of ultra-fast (thermal time constant, tau ˜ 80 mus) and high resolution (noise equivalent power, NEP ˜ 656 pW/Hz1/2) AlN NEMS resonant IR detectors with reduced pixel size comparable to the state-of-the-art microbolometers. Furthermore, the spectral selectivity of the proposed IR detector technology is investigated and demonstrated by the seamless integration of ultra-thin plasmonic absorbers. The first prototypes show strong absorption (> 92%) in mid-wavelength infrared range with a narrow bandwidth (full width at half maximum, FWHM < 17%), resulting in the demonstration of high resolution (NEP ˜ 130 pW/Hz1/2) narrowband infrared detectors suitable for IR spectroscopy and multispectral imaging system. The second part of the dissertation is focused on the discussion and development of a new class of IR wake-up sensors that can remain dormant, with near-zero power consumption, until awoken by an external signal of interest. The proposed near-zero power IR digitizer combines sensing, signal processing and comparator functionalities into a single passive microelectromechanical system capable of producing a digitized output bit in the presence of the unique infrared spectral signature associated to an event of interest. The prototypes reported in this dissertation are capable of producing a digitized output bit (i.e. a large and sharp OFF-to-ON state transition with ON/OFF conductance ratio > 1012 and subthreshold slope > 9 dec/nW) when exposed to IR radiation in a specific narrow spectral band (˜ 900 nm bandwidth in the mid-IR) with intensity above a power threshold of only ˜ 500 nW, which is not achievable with any existing photoswitch technologies. The two IR sensing elements presented here set a stepping stone towards the development of highly sensitive and persistent IR sensor nodes that required for the future event-driven wireless sensor networks.

Thesis survey results in the field of nursing regarding the use of complementary and alternative medical treatments in Turkey.

PubMed

Arslan, Gulsah Gurol; Denat, Yildiz; Dikmen, Yurdanur

2017-09-01

This descriptive literature review was planned to identify the prevalence of Complementary and Alternative Medicine (CAM) usage, frequency of usage, types/fields of use in master's theses and PhD dissertations based on the CAM methods, which are commonly used in nursing practice in Turkey. Data was collected in Turkey from February to March 2014 through a review of the National Thesis Centre (NTC) Archives at the Chairmanship of the Council of Higher Education and by obtaining the nursing theses/dissertations on CAM done between 1996 and 2013. Data were analysed by distribution of frequencies and percentages for publication year, number in sampling, method, case group, CAM type, and purpose of use/effectiveness. A total of 88 theses/dissertations were located. It was found that a majority of the theses/dissertations investigated were interventional. Investigation of the purpose of CAM use in theses/dissertations showed that the studies examined the effects of CAM on symptom control.

Design principles for functional liquid crystals

NASA Astrophysics Data System (ADS)

Bedolla Pantoja, Marco A.

The work described in this dissertation details how the properties of liquid crystals (LCs) can be utilized for chemical sensing of volatile organic compounds or as templates for the synthesis of polymer nanofibers. Through a series of experiments using thin films of various types of LCs, this work provides a fundamental understanding of the properties of confined LC systems that arise from the anisotropy, elasticity, and surface interactions of LCs. This dissertation is organized into two parts, as detailed below. In the first part of this dissertation, I present a new mechanism for detection of vapors of aromatic volatile organic compounds (VOCs) that exploits the elastic strain stored in thin films of nematic LCs. The discovery of this mechanism was enabled by the design of novel microfabricated structures that stabilize films of LCs with thicknesses from 0.7 - 30 microm. By exposing these LC films to vapors of toluene, a model for aromatic VOCs, I demonstrate that the response of the LC film to toluene depends on the thickness of the LC film and the identity of the supporting substrate. Furthermore, I show that the response to toluene can be increased sevenfold in elastically-strained thin films as compared to bulk LCs. Building further on the concept of elastically strained LCs, I describe the responsiveness of cholesteric and blue phase LCs to toluene. The work demonstrates that internal elastic strain stored within cholesteric LC phases can drive a transition into a so-called blue phase LC when vapors of toluene are introduced. When combined, these results show that engineering of elastic strain in LC materials offers the bases for a general and facile approach to design of stimuli-responsive LC systems. In the second part of this dissertation, I present the discovery of a novel method for the LC-templated synthesis of polymer nanofibers. By performing chemical vapor deposition of reactive polymer precursors into films of LCs, I observed the formation of dense mats of polymer fibers that extended from the solid substrate across the thickness of the LC film. Remarkably, these fibers possess uniform shapes, diameters and lengths. The results demonstrate that the morphological properties of the fibers (shape, diameter and length) are determined by the orientation, chemical structure and thickness of the LC used during polymerization. In a demonstration of these effects, mats of nanofibers exhibiting left-handed or right-handed optical activity were synthesized using left-handed or right-handed cholesteric LCs. The results presented in this dissertation are also used to motivate the proposal that growth of the nanofibers is controlled by local regions of high elastic strain in the LC at the tip of the nanofiber, which lead to preferential diffusion and subsequent addition of monomer to the apex of the growing polymeric structure. Finally, I discuss two examples that demonstrate potential applications of these nanofibers: (1) functionalization of mats of fibers with biologically-relevant molecules, and (2) fabrication of nanofibers in complex geometries. These experiments suggest that mats of polymeric nanofibers could find applications in biomedicine, filtration, chemical sensing or separation systems. Overall, these studies contribute new principles for the design of LC-based stimuli-responsive materials and for LC-templated synthesis of polymeric nanostructures using chemical vapor deposition. The principles reported in this dissertation provide guidance to the design of LC-based materials with broad potential engineering applications.

Clear-air radar observations of the atmospheric boundary layer

NASA Astrophysics Data System (ADS)

Ince, Turker

2001-10-01

This dissertation presents the design and operation of a high-resolution frequency-modulated continuous-wave (FM- CW) radar system to study the structure and dynamics of clear-air turbulence in the atmospheric boundary layer (ABL). This sensitive radar can image the vertical structure of the ABL with both high spatial and temporal resolutions, and provide both qualitative information about the morphology of clear-air structures and quantitative information on the intensity of fluctuations in refractive-index of air. The principles of operation and the hardware and data acquisition characteristics of the radar are described in the dissertation. In October 1999, the radar participated in the Cooperative Atmosphere-Surface Exchange Study (CASES'99) Experiment to characterize the temporal structure and evolution of the boundary-layer features in both convective and stable conditions. The observed structures include clear-air convection, boundary layer evolution, gravity waves, Kelvin-Helmholtz instabilities, stably stratified layers, and clear-air turbulence. Many of the S-band radar images also show high- reflectivity returns from Rayleigh scatterers such as insects. An adaptive median filtering technique based on local statistics has, therefore, been developed to discriminate between Bragg and Rayleigh scattering in clear-air radar observations. The filter is tested on radar observations of clear air convection with comparison to two commonly used image processing techniques. The dissertation also examines the statistical mean of the radar-measured C2n for clear-air convection, and compares it with the theoretical predictions. The study also shows that the inversion height, local thickness of the inversion layer, and the height of the elevated atmospheric layers can be estimated from the radar reflectivity measurements. In addition, comparisons to the radiosonde-based height estimates are made. To examine the temporal and spatial structure of C2n , the dissertation presents two case studies with the measurements of remote (the FM-CW radar and Doppler lidar) and in-situ (research aircraft, kite, and radiosonde) sensors from the stable nighttime boundary layer. It also presents a unique observation of evolution of the convective and nocturnal boundary layers by the S-band radar, and provides description of the observed boundary layer characteristics with the aid of in-situ measurements by the 55m instrumented tower and radiosonde.

Rhetoric and Public Address: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1980 (Vol. 41 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 16 titles deal with the following topics: (1) a psycholinguistic analysis of the rhetoric of Abba S. Eban; (2) synergetic tetrahedral communication models; (3) a form critical approach to the oral traditions of the black church…

Theatre and Oral Interpretation: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1983 (Vol. 44 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 17 titles deal with a variety of topics, including the following: (1) the relative effects of two creative drama approaches on the dramatic behavior and mental imagery ability of elementary school students; (2) the history of the…

Journalism and Journalism Education: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1980 (Vol. 41 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 18 titles deal with a variety of topics, including the following: (1) the status, function, and perceived needs of journalism in the high schools of West Virginia; (2) environmental pollution news coverage; (3) a critical history…

Reading Achievement: Characteristics Associated with Success and Failure: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," October through December 1977 (Vol. 38 Nos. 4 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 22 titles deal with a variety of topics, including the following: relationships between decoding skills and reading comprehension in college students, speed of retrieval of verbal information and patterns of oral reading errors,…

Reading and Study Skills and Instruction: Secondary: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1980 (Vol. 40 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 15 titles deal with the following topics: (1) a hierarchy of purposes for reading assignments applied to secondary school social studies; (2) the effects of sentence combining practice on reading comprehension; (3) the effects of…

Reading and Study Skills and Instruction: Secondary: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1981 (Vol. 42 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The ten titles deal with the following topics: (1) an inductive method for teaching three skills necessary for reading narrative fiction; (2) the use of reading strategies in secondary level content area classrooms; (3) seventh grade…

Journalism and Journalism Education: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," January through June 1984, (Vol. 44 Nos. 7 through 12).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 18 titles deal with the following topics: (1) the meaning of "Cold War" in two York, Pennsylvania, daily newspapers; (2) Tom Paine and the disclosure of secret French aid to the United States; (3) "Schenck V.…

Literature, Literary Response, and the Teaching of Literature: Abstracts of Doctoral Dissertations Published in "Dissertation Abstracts International," July through December 1983 (Vol. 44 Nos. 1 through 6).

ERIC Educational Resources Information Center

ERIC Clearinghouse on Reading and Communication Skills, Urbana, IL.

This collection of abstracts is part of a continuing series providing information on recent doctoral dissertations. The 29 titles deal with a variety of topics, including the following: (1) science fiction in elementary school science education; (2) the portrayal of black characters in children's literature; (3) UFOs and their correlates as a…