Digital Commons Network^™

Honduras Pawn And Policy Maker, Elizabeth P. Thornton

Graduate Program in International Studies Theses & Dissertations

A study of the weak state was conducted using the Honduras-U.S. relationship as a case study. Most existing literature, with the exception of Annette Baker Fox's The Power of Small States, does not analyze in detail a specific country's relationship with a powerful nation. This research examined the factors that helped a weak country maintain maneuverability in its domestic and foreign policies when under the influence of a strong power. Six conditions which facilitated maneuverability were: geographic proximity, rising nationalism, citizen participation in government, trade distribution and diversification, international pressure, and declining hegemony of the strong power. Events in Honduras …

Self-Esteem And Perceived Barriers To And Benefits Of Exercise Among Physically Active And Non-Physically Active College Students, Barbara Brown Bonheur

Ellmer School of Nursing Theses & Dissertations

The purpose of this exploratory study was to examine differences in self-esteem, perceived benefits of and perceived barriers to exercise between exercisers and non-exercisers and to determine if relationships existed between self-esteem, perceived benefits of exercise and perceived barriers to exercise, that could explain participation in regular aerobic exercise. A sample of 105 university students completed four questionnaires. The level of social desirability present in participant responses was also measured. Five hypotheses were tested. Utilizing t-tests, a significant difference was found between exercisers and non-exercisers on self-esteem, perceived benefits of exercise, and perceived barriers to exercise. The three variables (self-esteem, …

Dynamic Analysis Of Linear Structural System Using Ritz Vector Method And Substructuring Formulation, Vijay R. Modi

Civil & Environmental Engineering Theses & Dissertations

In this study, the substructuring formulation is incorporated into Ritz Vector method to obtain and solve the reduced system of dynamic equilibrium equations. Two-dimensional and three-dimensional truss problems are considered in the present study. The accuracy and computational time using the proposed technique are compared with known solutions. The effect of using different number of substructures and Ritz vectors are also investigated, equations solver is utilized to Moreover, a version of a parallel further enhance the numerical performance of the proposed technique on the FLEX/32 Multicomputer.

An Adaptive Remeshing Finite Element Method For High-Speed Compressible Flows Using Quadrilateral And Triangular Elements, Gururaja R. Vemaganti

Mechanical & Aerospace Engineering Theses & Dissertations

In this study a new adaptive remeshing method for high speed compressible flow analysis is presented. The method uses quadrilateral elements where possible, and triangles are introduced as needed. The primary goal of this study is to develop a remeshing method which uses both the concepts of unstructured and structured meshes for the finite element analysis to predict accurate aerodynamic heating in problems related to high speed viscous flows. The remeshing method uses a solution based on an old mesh to create a new mesh based on an advancing front technique. In the present implementation, a structured mesh of quadrilaterals …

Computer Technology For Executive Decision-Making In Urban Public Education Divisions In Virginia, Richard Kenneth Byrd

Theses and Dissertations in Urban Services - Urban Education

The purpose of this study was twofold. First, the study determines if Virginia urban public school executive leadership used automated informational systems to support policy, goal setting, and decision making typical of its job requirements. Secondly, the study describes the planning techniques specific to automated system development used by the school division where such automated executive support occurs.

The personal interview method was selected because it helps to insure 100 percent of the desired sample to participate. The interview technique insures responses to direct questions, to narrative responses sought, and to follow-up discussions necessary to insure clarification.

The instrument follows …

An Experimental Study Of Dewatering Of Alum Sludge, Uday G. Kelkar

Civil & Environmental Engineering Theses & Dissertations

The use of aluminum sulfate (Alum) as a coagulant for treating surface water was introduced in 1884. When this salt is added to water, the aluminum Ion hydrolyzes by reaction that consumes alkalinity in water. The gelatinous hydroxide thus formed in the reaction, carries suspended material with it as it settles. In addition, however, it is likely that positively charged hydroxyl-bridge dimmers and higher polymers are formed which interact specifically with the colloidal particles, bringing about coagulation. These gelatinous floes settle by gravity, called sludge, consists of relatively large quantities of suspended and colloidal inorganic and organic materials.

The disposal …

Politics Of Self-Destruction: The Virginia Republican Party Split Of 1895-1897, Michael Anthony Southwood

History Theses & Dissertations

In explaining the rise of Democratic rule in Virginia, political historians have overlooked the significance of the Republican split of 1895-1897. Drawn mainly from primary source materials, this thesis traces the rupture that divided the GOP leadership after the death of General William Mahone, one of the Commonwealth's most remarkable political figures. The controversial election of Mahone's successor (Colonel William Lamb of Norfolk) as party chairman in November 1895 sparked two years of bitter struggle, a conflict that ultimately left the state Republicans shattered as a political force. An understanding of Democratic dominance as it developed in Virginia is incomplete …

Task-Hemispheric Integrity Effect: Level Of Task Difficulty And Mental Workload In A Dual Task, Nancy E. Hite

Psychology Theses & Dissertations

The task-hemispheric integrity effect states that when a spatial and verbal task must be time-shared, superior performance would be obtained when the same hemisphere that processes information also controls the hand used to respond. The effect of increasing the level of task difficulty on an unstable tracking task on the concurrent performance of a dichotic listening task was investigated. The results indicated that performance on the unstable tracking task significantly deteriorated as task difficulty level increased in both single- and dual-task conditions. However, performance on both the unstable tracking task and the dichotic listening task was not influenced by hand …

Transient Hot-Film Sensor Response In A Shock Tube, Kelly Ryan Ortgies

Mechanical & Aerospace Engineering Theses & Dissertations

Shock tube experiments have been performed to determine the response of a hot-film sensor, mounted flush on the side-wall of a shock tube, to unsteady flow behind a normal shock wave. The present experiments attempt to isolate the response of the anemometer due only to the change in convective heat transfer at the hot-film surface. The experiments, performed at low supersonic shock speeds in air, are described along with the data acquisition procedure. The change in convective heat transfer i s deduced from the data and the results are compared with those from transient boundary-layer theory and another set of …

A Classification Approach For Automated Reasoning Systems--A Case Study In Graph Theory, Rong Lin

Computer Science Theses & Dissertations

Reasoning systems which create classifications of structured objects face the problem of how object descriptions can be used to reflect their components as well as relations among these components. Current reasoning systems on graph theory do not adequately provide models to discover complex relations among mathematical concepts (eg: relations involving subgraphs) mainly due to the inability to solve this problem. This thesis presents an approach to construct a knowledge-based system, GC (Graph Classification), which overcomes this difficulty in performing automated reasoning in graph theory. We describe graph concepts based on an attribute called Linear Recursive Constructivity (LRC). LRC defines classes …

Study Of Direct Semiconductor Materials For An Optically Controlled Switch, Sung Taek Ko

Electrical & Computer Engineering Theses & Dissertations

A model for a bulk GaAs photoconductive switch has been developed and solved to determine the performance of the device in closing and opening switch applications. The GaAs material has been characterized by deep level transient spectroscopy (DLTS). Two electron traps (EL2 and EL5) and one hole trap (Cu_B} have been detected and were included in the model. Simulation studies are performed on several GaAs switch systems composed of different combinations and density of deep levels to investigate the influence of deep traps in a photoconductive switch system. The electron occupancy of each deep trap is traced in …

Experimental Study Of Pressure And Heating Rate On A Swept Cylindrical Leading Edge Resulting From Swept Shock Wave Interference, Christopher E. Glass

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental study of the effects of leading edge sweep on surface pressure and heat transfer rate for swept shock wave interference is presented. This study was conducted as a cooperative agreement between NASA Langley Research Center and Calspan-University of Buffalo Research Center. Experimental tests were conducted in the Calspan 48-inch Hypersonic Shock Tunnel at a nominal Mach number of 8, nominal unit Reynolds number of 1.5 x 10⁶ per foot, leading edge and incident shock generator sweep angles of 0^o, 15^o, and 30^o, and incident shock generator angle-of-attack fixed at 12.5^{o …}

Expert Systems For Automated Maintenance Of A Mars Oxygen Production System, Ming-Tsang Ho

Mechanical & Aerospace Engineering Theses & Dissertations

A prototype expert system has been developed for maintaining autonomous operation of a Mars oxygen production system. Normal operation conditions and failure modes according to certain desired criteria are tested and identified. Several schemes for failure detection and isolation using forward chaining, backward chaining, knowledge-based and rule-based are devised to perform several housekeeping functions. These functions include self-health checkout, an emergency shut down program, fault detection and conventional control activities. An effort has been made to derive the dynamic model of the system using Bond-Graph technique in order to develop the model-based failure detection and isolation scheme by estimation method. …

Population Variation In The Mitochondrial-Dna Of Two Marine Organisms: The Hard Shell Clam Mercenaria Spp. And The Killifish, Fundulus Heteroclitus, Bonnie Lynn Brown

OES Theses and Dissertations

The two major topics are covered in this dissertation: the integration of molecular genetic tools with applied aquacultural research and short-term evolutionary dynamics. The first study investigated the extent of geographic differentiation of native clam stocks along the U.S. east and Gulf coasts. Clam mitochondrial DNA (mtDNA) demonstrated size polymorphism (16.5-19.0 kb) and restriction site heteroplasmy. Size heteroplasmic individuals occurred at a frequencies of 0-89% in clam populations. Restriction site heteroplasmy occurred in 12% of the 317 individuals assayed. Results of the study indicated that although harbouring a wealth of genetic variation, clams from northern regions were similar and lacked …

The Effects Of Nonlinearities On The Optimal Design Of Forced Vibrating Beams, Cheryl Celestine Jackson

Mechanical & Aerospace Engineering Theses & Dissertations

The optimal design of a beam under harmonic excitations is formulated and solved numerically for linear and nonlinear forced vibration theories. The beam has a nonuniform cross-sect ion, whose thickness can change during the optimization procedure. Based on the numerical results, for the given input frequency range, the linear vibration theory produces a more conservative design than the nonlinear vibration theory.

The analytical formulation for both theories is presented. For the linear case, a mean case is defined for the self-weight on a beam, and an alternating case is defined for input forcing frequencies which cause fatigue variations on a …

Low Speed Flowfield Characterization By Infrared Measurements Of Surface Temperatures, Ehud Gartenberg

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental program was aimed at identifying areas in low speed aerodynamic research where infrared imaging systems can make significant contributions. Implementing a new technique, a long electrically heated wire was placed across a laminar jet. By measuring the temperature distribution along the wire with the IR imaging camera, the flow behavior was identified. Furthermore, using Nusselt number correlations, the velocity distribution could be deduced. The same approach was used to survey wakes behind cylinders in a wind-tunnel. This method is suited to investigate flows with position dependent velocities, e.g., boundary layers, confined flows, jets, wakes and shear layers. It …

Performance Modeling And Enhancement For The Atamm Data Flow Architecture, Sukhamoy Som

Electrical & Computer Engineering Theses & Dissertations

Algorithm To Architecture Mapping Model (ATAMM) is a new marked graph model from which the rules for data and control flow in a homogeneous, multicomputer, data flow architecture may be defined. This research is concerned with performance modeling and performance enhancement for periodic execution of large-grain, decision-free algorithms in such an ATAMM defined architecture. Performance measures and bounds are established. Algorithm transformation techniques are identified for performance enhancement and reduction of computing element requirements. Operating strategies are developed for optimum time performance and for sub-optimum time performance under limited availability of computing elements. An ATAMM simulator is used to test …

Fixed Point Theorems For Compatible Multi-Valued And Single-Valued Mappings, Hideaki Kaneko, Salvatore Sessa

Mathematics & Statistics Faculty Publications

The notion of compatibility for point-to-point mappings recently defined by Jungck is generalized to include multi-valued mappings. This idea is used to establish a fixed point theorem for a generalized contractive multi-valued mapping and a single-valued mapping.

Effects Of Nose Bluntness And Shock-Shock Interactions On Blunt Bodies In Viscous Hypersonic Flows, Dal J. Singh

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical study has been conducted to investigate the effects of blunt leading edges on the viscous flow field around a hypersonic vehicle such as the proposed National Aero-Space Plane. Attention is focused on two specific regions of the flow field. Analysis of these flow regions is required to accurately predict the overall flow field as well as to get necessary information on localized zones of high pressure and intense heating.

The forebody is modeled by slender cones and ogives with spherically blunted nose. A combination of Navier-Stokes and parabolized Navier-Stokes equations is used to compute the flow field. The …

Automatically Generating Functional Tests From Specifications - A Knowledge Based Constraint Logical Programming Approach, Ji Chen

Computer Science Theses & Dissertations

Recent experimental results indicate that functional testing is one of the most effective methods in detecting certain classes of faults. Very little work has been done in automating functional testing. This thesis research develops a method, called hierarchical partition, for automating functional testing. The key to our approach is the utilization of a pre-existing knowledge base about the domain of discourse. Several approaches to knowledge organiza­tion are discussed along with the resulting effects on the quantity and quality of functional tests produced. This research is an application and development of Generic Constraint Logic Programming and the Knowledge Driven …

Gaas Photoconductive Closing Switches With High Dark Resistance And Microsecond Conductivity Decay, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, R. Germer, G. M. Loubriel, F. J. Zutavern

Electrical & Computer Engineering Faculty Publications

Silicon-doped n-type gallium arsenide crystals, compensated with diffused copper, were studied with respect to their application as photoconductive, high-power closing switches. The attractive features of GaAs:Cu switches are their high dark resistivity, their efficient activation with Nd:YAG laser radiation, and their microsecond conductivity decay time constant. In the authors' experiment, electric fields are high as 19 kV/cm were switched, and current densities of up to 10 kA/cm² were conducted through a closely compensated crystal. At field strengths greater than approximately 10 kV/cm, a voltage `lock-on' effect was observed.

Nanosecond Optical Quenching Of Photoconductivity In A Bulk Gaas Switch, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, S. T. Ko

Electrical & Computer Engineering Faculty Publications

Persistent photoconductivity in copper-compensated, silicon-doped semi-insulating gallium arsenide with a time constant as large as 30 µs has been excited by sub-band-gap laser radiation of photon energy greater than 1 eV. This photoconductivity has been quenched on a nanosecond time scale by laser radiation of photon energy less than 1 eV. The proven ability to turn the switch conductance on and off on command, and to scale the switch to high power could make this semiconductor material the basis of an optically controlled pulsed-power closing and opening switch.

Optical Recording Aspects Of Rf Magnetron Sputtered Iron-Garnet Films, J.P. Krumme, V. Doormann, P. Hansen, H. Baumgart, J. Petruzzello, M.P.A. Viegers

Electrical & Computer Engineering Faculty Publications

The intrinsic magneto-optical readout performance in reflection is calculated for bismuth and cobalt-substituted iron-garnet films on a multilayer interference mirror at 800-, 633-, 488-, and 420-nm wavelengths and is compared with that of a trilayer medium composed of an antireflection layer, a rare-earth transition-metal film, and a metallic mirror. It is found, when disregarding inhomogeneities, like irregular domain shape, ripple of the magnetic anisotropy, and surface roughness, that iron garnets are superior to rare-earth transition-metal films at blue to near-ultraviolet wavelengths if operated at thicknesses where optical interference occurs in the magnetic layer. Optical transmittance at these thicknesses is sufficiently …

An Arrayed Hot-Film Sensor For Detection Of Laminar Boundary-Layer Flow Disturbance Spatial Characteristics, Michael S. Wusk

Mechanical & Aerospace Engineering Theses & Dissertations

An arrayed hot-film sensor has been developed for use in laminar boundary-layer research for the detection of crossflow or Gortler vortices. This sensor has been developed to detect spatial variations in heat transfer and velocity perturbations which are characteristic of crossflow or Gortler vortices. The sensor is ultimately intended for flight research applications. This thesis describes the sensor, its principles of operation, signal analysis techniques, and experimental results illustrating the spatial detection capabilities of this specialized hot-film device. Discretely placed spheres placed in the boundary layer created alternating regions of undisturbed and disturbed laminar flow over a prototype sensor. Flow …

A Structured Light Method For Sensing Alignment During Automated Truss Assembly, Jayesh K. Champaneri

Electrical & Computer Engineering Theses & Dissertations

A new method using structured light is proposed to obtain visual feedback information for aligning two cylindrical beams. For a robotic system employed to perform alignment operations in real time it is essential that the accompanying vision system does not pose a heavy burden on the computing machinery and reduce the overall speed of operation. The method proposed here involves two stripes of light projected on each cylinder. One picture frame is sufficient to completely determine the position of the cylinder in space. An experiment was conducted to demonstrate the principle of this method. Results showed that the errors involved …

The Effects Of Low Doses (1 To 500 Kilograys) Of 100-Kev Electrons On Four Polymers, Cynthia Anne Bradbury

Physics Theses & Dissertations

Commercial films of polyetherimide (PEI), polyetheretherimide (PEEI), polyethylene terephthalate (PET), and polycarbonate (PC) were exposed in vacuum to l 00-keV electron radiation to total absorbed doses of l, l 0, l 00, 300, and 500 kilograys. The concentration of radiation-generated radicals, as measured by electron paramagnetic resonance (EPR), increased by over an order of magnitude in all four polymers. Correspondingly, the intensity of the infrared absorption peaks increased uniformly for all doses. Solubility tests resulted in decreased solubility in all polymers. IR, EPR, and solubility suggest dehydrogenation of the aliphatic C-H and phenyl C-H sites. The data indicated that cross …

Numerical Simulation Of Turbulent Flows Past Three-Dimensional Cavities, Shivakumar Srinivasan

Mechanical & Aerospace Engineering Theses & Dissertations

Computations have been performed to simulate turbulent supersonic, transonic, and subsonic flows past three-dimensional deep, transitional, and shallow cavities. Simulation of these self sustained oscillatory flows has been generated through time accurate solutions of Reynolds averaged full Navier-Stokes equations using the explicit MacCormack scheme. The Reynolds stresses have been modeled, using the Baldwin-Lomax algebraic turbulence model with certain modifications. The computational results include instantaneous and time averaged flow properties everywhere in the computational domain. Time series analyses have been performed for the instantaneous pressure values on the cavity floor. Comparison with experimental data is made in terms of the mean …

Viscous Shock Layer Analysis Of Hypersonic Flows Over Long Slender Vehicles, Kam-Pui Lee

Mechanical & Aerospace Engineering Theses & Dissertations

A method for solving the viscous shock-layer equations for hypersonic flows over long slender bodies is presented. The governing equations are solved by employing a spatial-marching implicit finite-difference technique. The two first-order equations, continuity and normal momentum, are solved simultaneously as a coupled set. This method yields a simple and computationally efficient technique.

Flows past hyperboloids and sphere cones with body half angles of five to 35 degrees are considered. The flow conditions included are from high Reynolds numbers at low altitudes to low Reynolds numbers at high altitudes. Detailed comparisons have been made with other predictions and experimental data …

Performance Appraisal Ratings As A Function Of Source Of Ratings And Purpose Of The Appraisal, Richard J. Tannenbaum

Psychology Theses & Dissertations

This study investigated the effects of purpose of appraisal ratings and source of appraisal ratings on four dependent measures: leniency, halo, variability, and construct validity. The purpose factor was comprised of four different levels: merit pay, performance improvement, research only, and no defined appraisal purpose. The rating source factor was comprised of two different levels: incumbent self-ratings, and supervisor ratings. One hundred and nineteen nursing assistants provided the self-ratings, and 39 nurses provided the supervisor ratings. Both sets of ratings were made using a 13-dimension graphic-type rating scale. Analysis of variance procedures were used to test the effects of appraisal …

John Of Gaunt And His Use Of Marriage, Christopher Park Ross

History Theses & Dissertations

The problem under examination is to determine to what extent were the public policy pursuits of John of Gaunt, Duke of Lancaster, designed to expand the patrimony and influence of the house of Lancaster. Gaunt's actions have been placed in a wider historical context. His claims to various European lands from Provence to Scotland have been examined. His use of the marriages of himself and of his children to strengthen the prestige of his house have been scrutinized. The result of this study has been to show Gaunt's loyalty to what he perceived to be the interests of his immediate …