Digital Commons Network^™

Gas Permeation Measurements On Small Polymer Specimens, Karen S. Burns

Chemistry & Biochemistry Theses & Dissertations

Mass spectrometry was used to measure oxygen and nitrogen permeabilities while polarography was used to measure oxygen permeabilities for several contact lens materials. Applicable sample holders were designed and fabricated to accommodate curved and flat specimens with surface areas of 0.5 cm² and 1.0 cm² and thicknesses between 0.025 mm and 0.500 mm. A prepared standard was used to calibrate the mass spectrometric analyses.

The oxygen permeability values determined by mass spectrometry were significantly greater than those determined by polarography. This was attributed to the phase boundary phenomena and the limiting oxygen permeance of water inherent in the …

Analysis And Design Sensitivity Computations Of Nonlinear Free And Forced Vibrations Of Stepped Beams, Yong Xiang Xue

Mechanical & Aerospace Engineering Theses & Dissertations

A finite element method is developed in this thesis for analyzing stepped beams under nonlinear free and forced vibrations. A new assumption is made to improve an existing finite element procedure for treating beams of nonuniform cross sections. The geometric nonlinearity results from the nonlinear, strain-displacement relation due to large deflection of a beam.

Based on an improved finite element procedure a computational method is then established for design sensitivity analyses of nonlinear eigenproblems pertaining to the free and forced nonlinear vibrations of beams. It is found that the equation for computing the design sensitivity of eigenvector is linear and …

Tardive Dyskinesia: A Prevalence Study In An Outpatient Population, Virginia J. Ravizza

Community & Environmental Health Theses & Dissertations

The purpose of this prevalence study was to assess the occurrence of tardive dyskinesia among a chronically mentally ill sample of a suburban mental health clinic. The participants in this study were selected from clients of a suburban mental health clinic who agreed to participate in this prevalence study. There were 45 participants--17 males and 28 females.

The Abnormal Involuntary Movement Scale (AIMS) was selected as the instrument to measure the abnormal involuntary movements exhibited by the participants of the study on the day of testing. The testing occurred during a specific time period, June 8, 1987 to July 2, …

Model Of Hot-Film Sensor With Substrate Effects, David Mcalpine Judge

Electrical & Computer Engineering Theses & Dissertations

A detailed mathematical model is constructed to investigate the frequency response of a hot-film anemometer system. Since several diverse factors affect the frequency response, the analysis is broken down into three main parts. Each part is a detailed mathematical model. The first model consists of the ordinary differential equations which govern the electronics of the feedback system and heat transfer of the sensor. An important simplification in this model is that the rate of heat conduction from the sensor to its substrate is constant.

In the second model the unsteady state heat transfer properties of the substrate are examined by …

Job Satisfaction Among Female Employees As Predicted By Work Friendships, Melinda Jan Montgomery

Psychology Theses & Dissertations

The purpose of the present study was to predict job satisfaction among female employees using social environment variables which relate to work friendships. The predictor variables used were target persons perceived job satisfaction level, breadth of workplace friendships, frequency of interaction, friendship quality, and the interaction of friendship and quality.

Thirty-seven female faculty members and 88 female staff employees at Old Dominion University served as subjects. The subjects were asked to complete the Communal scale {Clark, 1986), selected sections of the Acquaintance Description Form (Wright, 1969, 1974), and the work-in-general scale from the Job Descriptive Index on a co-worker considered …

A Study Of Flow Separation In Transonic Flow Using Inviscid And Viscous Cfd Schemes, James Andrew Rhodes

Mechanical & Aerospace Engineering Theses & Dissertations

A comparison of flow separation in transonic flows is made using various computational schemes which solve the Euler and the Navier-Stokes equations of fluid mechanics. The flows examined are computed using several simple two-dimensional configurations including a backward facing step and a bump in a channel. Comparison of the results obtained using shock fitting and flux vector splitting methods are presented and the results obtained using the Euler codes are compared to results on the same configurations using a code which solves the Navier-Stokes equations.

Perceived Job Stress In Critical Care Nursing In A Military Setting, Jeannette Theriault

Ellmer School of Nursing Theses & Dissertations

The purposes of this study. were: to explore job-related perceptions of stress in a group of military critical care nurses; and to determine if differences in anxiety and stress levels existed between nurses working in coronary care (CCCU) and medical/surgical intensive care (ICU) settings using the State/Trait Anxiety Inventory and the Questionnaire of Stressful Factors in Intensive Care. A free response question and a force-response checklist were also used to identify and rank work-related stressors. The sample of Navy nurses (n=105) consisted of 39 CCU nurses, 62 medical/surgical ICU nurses and 4 critical care supervisors. The results of the mailed …

Slavery And The Early Teutonic Codes A.D. 400-800: A Legal Paradigm Shift, Elizabeth Thompson Harris

History Theses & Dissertations

This study examines the institution of slavery in the customary legal codes of seven Germanic tribes: the Burgundians, Lombards, Franks, Anglo-Saxons, Alamanni, Bavarians, and Visigoths. It describes the status of slaves within each society and assesses various factors contributing to both the recrudescence of slavery throughout the period of the invasions and its subsequent demise during the ninth and tenth centuries. The research is based primarily on the titles within the Germanic codes themselves, chronicles, contemporary Roman historical writing, and Roman legislation.

An important legal transformation made evident throughout the Germanic codes testifies to the replacement of complete subjection by …

Growth Potential Of Young Black Sea Bass, Centropristis Striata, In Artificial Environments, Joung Won Kim

OES Theses and Dissertations

The growth potential of the commercially important marine finfish, black sea bass (Centropristis striata), was examined for aquaculture under controlled conditions. The effect of food and body weight on growth was evaluated using juveniles and young black sea bass cultured with a natural diet and a commercial diet at various feeding levels.

Growth was affected by type of food, food consumption rate, and fish body weight. For fish having positive weight gain, absolute growth rate (gram/day) increased exponentially as food consumption rate (percent of body weight per day) and/or body weight increased. Instantaneous growth rate (percent of body weight per …

Determination Of Amino Acids And Chloramino Acids In Municipal Wastewater, Jeffrey Taylor Jewell

Chemistry & Biochemistry Theses & Dissertations

It is well known that unchlorinated municipal wastewater contains high levels of organic and inorganic amino nitrogen compounds, the single most abundant amino-N species being ammonia. Upon chlorination, these compounds are transformed almost instantaneously and quantitatively into N-chloramino derivatives. The organic chloramines have been shown to

interfere with disinfection and have lower disinfection capacities than their inorganic counterpart monochloramine. The environmental effects imposed by the discharge of these compounds into natural receiving waters is unknown. This study has shown that amino acid precursors for N-chloramino acids range in concentration from 1.4 X 10^-7 M to 9.0 X 10^{-7 …}

Psychologists' Volunteering: Attitudes, Beliefs, And Behaviors Toward Psychotherapy Research, James Perry Howell

Psychology Theses & Dissertations

Psychologists' volunteering behavior and attitudes toward psychotherapy research were studied using a mail survey. A random sample of 248 male and 248 female doctoral-level members of Division 29 (Psychotherapy) of the American Psychological Association served as subjects. The cover letter requesting their participation in this study contained the systematic manipulation of variables believed to affect volunteering behavior: recruiter gender, normative nature of volunteering for the study, and perceived social importance of the study. The therapist variables of gender, age, and years of experience were also studied in order to determine if volunteerism might result in biased sampling across these variables. …

Implications Of A Family Systems Orientation For Preventing Psychiatric Hospitalization, James Howard Bullock

Psychology Theses & Dissertations

The present study evaluated the implications of a family systems approach for preventing psychiatric hospitalization by comparing the behavior of field clinicians who professed a systems view versus clinicians who held more traditional nonsystems views. The focus of the investigation was the clinical assessments and decisions of 31 clinicians who worked at five Virginia public mental health centers as they prescreened (i.e., evaluated need for inpatient treatment) 171 candidates for hospitalization. Q-technique was employed to determine theoretical orientation.

It was hypothesized that clinicians who held a systems view would be more likely than nonsystems therapists to evaluate and attempt to …

Computation Of 2-D And 3-D Natural Convection Heat Transfer In Closed And Vented Cavities, T. O. Mohieldin

Mechanical & Aerospace Engineering Theses & Dissertations

The natural convective heat transfer in closed and vented cavities has been studied numerically, using the primitive variables formulation. A two-and three-dimensional enclosure, and a two-dimensional Trombe Wall channel geometries are considered. The flow has been assumed to remain Laminar, and Boussinesq approximation is invoked for solving the governing equations, The finite-difference method used in this study, is based on the SIMPLER algorithm which uses a combination of central and upwind differencing scheme to obtain stable numerical results.

For both geometries, namely the closed and vented cavities, the fundamental nature of the fluid dynamic and heat transfer characteristics is revealed …

An Annual Study Of Phytoplankton Composition And Associated Environmental Conditions Of Lake Trashmore, Virginia Beach, Virginia, Seba B. Sheavly

Biological Sciences Theses & Dissertations

A 12 month study of Lake Trashmore was conducted on phytoplankton composition, inorganic nutrients and their seasonal associations. The dominant phytoplankton groups observed were diatoms, chlorophyceans and cyanobacteria. Phytoplankton assemblage patterns were coupled with pH, temperature, dissolved oxygen, nitrites and silicates. Diatoms dominated during periods of high nutrient concentrations, cooler temperatures and an unstable water column. Cyanobacteria forms dominated during periods of warmer temperatures, higher pH and decreased nitrogen and dissolved oxygen concentrations. A seasonal community shift occurred from cyanobacterial dominance to chlorophycean dominance when pH levels decreased. The lake is eutrophic based on indices of chlorophyll a concentrations, transparency …

A Taxonomic Survey Of The Family Gyrinidae (Coleoptera) Of The State Of Virginia, Jerrold R. Harris

Biological Sciences Theses & Dissertations

The aquatic insect fanua of Virginia is not very well known. This is especially true of the order Coleoptera. There are few taxonomic studies on the families of Coleoptera found within the state, and one of the least known is the family Gyrinidae. It is the intent of this study to determine what species of Gyrinidae are found within the state and where they are found. Collections of the beetles were made throughout the state from March to December.

Twenty-one species of Gyrinidae were identified in Virginia, nine species of Dineutus and 12 species of Gyrinus. The family is distributed …

The Influence Of Transverse Magnetic Fields On The Current-Voltage Characteristics Of Glow Discharges, Thomas J. Powers

Electrical & Computer Engineering Theses & Dissertations

In low pressure discharges, operated in electronegative gas mixtures to the right of the Paschen curve minimum, the discharge resistance can be increased by application of transverse magnetic fields. In this range of operation, both the mean free path and the larmor radius are small compared to the discharge dimensions. The relationship between the electric field and the magnetic field is therefore controlled by electron- molecule collisional processes. Specifically, the magnetically induced increase in the discharge resistance is caused by a downward shift of the electron energy distribution which leads to an increase in attachment and a reduction in ionization. …

The Impact Of Orientation Training On Spatial Cognition And Spatial Behavior In Elderly Shoppers, Elizabeth Ann Mathes

Psychology Theses & Dissertations

The present study focuses on the acquisition of spatial knowledge in a large-scale, novel environment and on the interrelationships among psychometric tests of imagery, psychometric tests of spatial abilities, and experimental tasks involving spatial knowledge. Forty elderly females were provided microspatial information by four means: cartography; videotape; verbal description; and verbal description with imagery instructions. Analyses of behavior in a simulated shopping task within a suburban shop­ ping mall revealed differences in performance only for efficiency in Route Selection task. Cartographic and verbal presentations resulted in greater efficiency than did verbal description with imagery instructions or video­ tape presentations. Supplemental …

Software Tools For Performance Evaluation Of Concurrent Processing, Rodrogo A. Obando

Electrical & Computer Engineering Theses & Dissertations

The development and use of software tools for performance evaluation of concurrent processing is presented in this thesis. The particular concurrent processing architecture proposed by Stoughton and Mielke is investigated. The modelling of this architecture is based on Petri net theory and it can be studied making use of circuit theory. Computation of lower bounds for Time Between Outputs (TBO) and Time Between Input and Output (TBIO) can be accomplished by using principles of circuit theory, among others. This new modelling needs to be deeply evaluated and studied. This evaluation and study is accomplished with the tools developed and presented …

Factors Affecting The Efficacy Of Rater Training: Information Type And Mode Of Presentation, Todd A. Silverhart

Psychology Theses & Dissertations

In order to enhance the quality of performance ratings, researchers have directed their efforts towards training raters to evaluate performance more accurately. The purpose of the present study was to examine two factors that may affect the efficacy of rater training for improving the accuracy of performance ratings. One factor was the type of information that was presented during training (target score information, behavioral rationale for target scores, or a combination of target score and behavioral rationale). The second factor was the mode in which information was presented during training (feedback or feedforward). In addition to assessing the unique contribution …

Analysis Of Phytoplankton And Particle Variability At A Warm Core Ring/Shelf Break Front Using Flow Cytometry, Kimberly G. Davis

OES Theses and Dissertations

Particle variability at a Gulf Stream warm core ring/ shelf break front on 09 Nay 1985 was analyzed. Single particle measurements of fluorescence, perpendicular light scatter, and volume were made using a FACS Analyzer flow cytometer. Advantages and disadvantages of at-sea use of the instrument are described. To evaluate the flow cytometry data, individual particle data were compared with bulk phytoplankton and particle measurements. Abundance and size distributions of fluorescent and non-fluorescent particles indicated a convergence zone at the front while upwelling was likely within the ring perimeter. Variability in fluorescence (approximating chlorophyll A) and cell biovolume exposed regions of …

A Comparison Of Potential Fishing Methods Associated With Fish Aggregating Devices Off The Northeast Coast Of Puerto Rico, Alan M. Friedlander

OES Theses and Dissertations

Six fish aggregating devices (FADs) were deployed in June and monitored through December 1986. Emphasis was placed on trolling, live-bait handlining and longlining.

There was a significant difference (x2 = 7.815, pCoryphaena hippurus) which made up 64.2% of the catch.

Handlining at night around inshore buoys for one boat yielded 82.7 kg per trip. Pelagic fish comprised 83.9% of the catch, with the majority (81.4%) being kingfish (Scomberomorous cavalla). Catch rates were 50% higher and the species diversity much greater on the FADs versus control during experimental nightfishing, but the difference was not significant.

Longlining resulted in 3.4 …

Processes Which Create And Destroy Stratification In The South Atlantic Bight During Gabex Ii, Rebecca Lynn Lovingood

OES Theses and Dissertations

The stratification present on the South Atlantic Bight (SAB) during the summertime is influenced by creative forces, namely surface heating, precipitation, fresh water runoff and advection of Gulf Stream water, and destructive forces, these being wind, bottom currents, tides, evaporation and cooling. During the summer of 1981 the Georgia Bight Experiment II (GABEX II) was conducted to evaluate the Gulf Stream intrusions on the shelf dynamics. Calculations using potential energy as an indicator of stratification showed that the mixing forces were strong enough to destroy the stratification if the advection of buoyancy is ignored. During this period, however, the potential …

Laminar Viscous Effects On Longitudinal Dispersion In Tidal Froude Models, Larry H. White

OES Theses and Dissertations

A laboratory investigation was designed to test the ability of a tidal Froude model operated according to the minimum Reynolds number criterion of 1400 to simulate the longitudinal dispersion of its turbulent, laboratory prototype in the absence of depth distortion and density stratification. To examine the model's performance, comparative tracer-dye dispersion tests were conducted in the model and in the prototype to determine spatial and temporal longitudinal dye distributions. Froude similitude of cross-sectional mean tide heights and current velocities was achieved. The minimum Reynolds number criterion did not guarantee turbulent flow throughout all tidal stages, prolonged periods of laminar flow …

Synthesis Of Potential Long Acting Calcium Channel Antagonists: A Study Of 1,4-Dihydropyridine Analogs, Thomas E. Christos

Chemistry & Biochemistry Theses & Dissertations

An investigation was undertaken to synthesize and evaluate longer acting analogs to the antihypertensive agent nifedipine. Analogs that are capable of covalent bonding to the nifedipine receptor were considered. These compounds may show increased activity as they will remain at the receptor for a longer period of time.

During the course of this study, previously unreported and unexpected products were encountered and lead to a more intense examination of the Hantzsch synthesis. Of particular interest was the oxazolidine 25 which was a major component of the Hantzsch synthesis when ethanolamine was used instead of ammonium hydroxide. Also isolated during this …

Reactions Of Organic N-Chloramines In The Gastric Fluid Of The Rat, Kathryn E. Mazina

Chemistry & Biochemistry Theses & Dissertations

Using chlorine as a drinking water disinfectant may have potential health effects due to its reactivity with organic amino nitrogen compounds found in the stomach. Organic N-chloramines have been shown to form in the stomachs of laboratory rats. The possible reactions of N-chloramines in the stomach fluid were examined in this study using a model radiolabeled N-chloramine. ³⁶Cl-N-Chloropiperidine, was synthesized and purified to remove ³⁶Cl-chloride. Stomach fluid was obtained from Sprague-Dawley rats which had been first fasted for 24 or 48 hours and then administered 3 mL of deionized water. Different concentrations of radiolabeled chloramine were reacted with …

Direct Simulation Of Hypersonic Transitional Flows Over Blunt Slender Bodies, Vincent Cuda Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Hypersonic transitional flow has been studied using the Direct Simulation Monte Carlo method. The cylindrically blunted wedge and spherically blunted cone were examined for body half angles of 0°, 5° and 10°, at a flight velocity of 7.5 km/s, zero angle of incidence and altitudes of 70 to 100 km. Those geometries and flow conditions are important considerations for hypersonic vehicles currently under design. Surface chemistry was examined for diffuse, finite-catalytic surfaces. Nonequilibrium chemistry and nonequilibrium thermodynamics were considered for both configurations at all altitudes.

Numerical simulations showed that rarefied gas effects, such as surface temperature jump and velocity slip, …

Topology And Grid Adaption For High-Speed Flow Computations, Jamshid Samareh Abolhassani

Mechanical & Aerospace Engineering Theses & Dissertations

This study investigates the effects of grid topology and grid adaption on numerical solutions of the Navier-Stokes equations. In the first part of this study, a general procedure is presented for computation of high-speed flow over complex three-dimensional configurations. This includes the grid generation and solution algorithm for Navier-Stokes equations in a general three-dimensional curvilinear coordinate system. The flow field is simulated on the surface of a Butler wing in a uniform stream. Results are presented for Mach number 3.5 and a Reynolds number of 2,000,000. The O-type and H-type grids have been used for this study, and the results …

Statewide Higher Education Governing Board Decision Making In Capital Project Planning, Richard Charles Runner

Theses and Dissertations in Urban Services - Urban Education

Funds spent for capital construction in the United States reached $4.3 billion in 1985. As the amount of funds for higher education capital construction has increased, so has the concern for adequate controls on capital spending. The scope and size of the existing physical plants and the number of construction or remodeling projects currently underway call for careful scrutiny of the manner in which public governing boards carry out their responsibilities on the public's behalf.

The primary focus of this study was the involvement of statewide higher education governing boards in the review and approval of capital projects. The stated …

Cross-Shore Sediment Transport In Relation To Waves And Currents In A Groin Compartment, Hyo Jin Kang

OES Theses and Dissertations

In nearshore areas waves are generally irregular, and the irregular wave-induced currents have different peak velocities (magnitude asymmetry) and durations (duration asymmetry) between forward and backward motions. These asymmetries may produce a net cross-shore sediment transport in one direction. The sediment transport mostly occurs as bedload where the waves are non-breaking.

Sediment transport on a sloping bed is also affected by gravity, and accordingly the Shields parameter should be re-evaluated for a grain on a sloping bed. It was also found that the affect of a steady current that interacts nonlinearly with the waves was important for the cross-shore sediment …

An Intergenerational Investigation Of Urban Preferences, Angelique A. Gavin

Psychology Theses & Dissertations

The present study attempts to evaluate the urban designs of three cohorts, as well as to investigate the ability of these three age groups to design desirable urban settings for the other two cohorts. Children, young adults, and elderly adults (mean ages= 10, 33, and 69 respectively) designed the "ideal" town for theirs and the other two cohorts. Multidimensional scaling analyses allowed for cross generational comparisons of the composite age-specific maps. Elderly adults were better at taking the perspective of the other two groups in anticipating their urban needs, young adults were the poorest predictors, and children could anticipate the …