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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 …

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 …

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 …

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 …

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 …

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 …

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. …

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 …

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 …

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 …

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 …

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, …

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. …

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 …

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 …

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 …

The Influence Of Direct Versus Indirect Observation, Candidate Report Format, And Assessor Training On The Accuracy Of Assessor Ratings, Rudolph L. Johnson Jr.

Psychology Theses & Dissertations

Within the assessment center method, assessors' preliminary evaluations of candidates' performance are typically based on information obtained through direct observation of the candidate's performance in the situational exercise, or on another assessor's report of that performance. This variation is somewhat disconcerting, however, in that its impact on assessor ratings remains largely unstudied. The primary focus of the present study was to assess the differential effects of observation type (i.e., direct observation, dimension-specific report, narrative report) on various measures of rating accuracy. In addition, the present study investigated cognitive modeling as an assessor training strategy, and its impact on rating accuracy. …

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 …}

Experimental Parametric Study Of A True Airspeed Sensor, Adel R. Ibrahim

Mechanical & Aerospace Engineering Theses & Dissertations

The results of an experimental parametric study of a true airspeed sensor are presented. The objective of this study was primarily to investigate experimentally the parameters that effect the frequency response of the true airspeed sensor. A secondary objective was to identify the sensor configuration which achieved the best performance. The model used to conduct these experiments basically consisted of swirl generator and vortex tube sections and pick-up signal system. A regression analysis was performed on the experimental results to obtain the effect of each parameter individually on the frequency response. The most significant parameters were selected by the regression …

Testing Orem's Dependent Care Agency Construct: Parents As Health Educators In The Home, Joann M. Baldwin

Ellmer School of Nursing Theses & Dissertations

The capacity of parents to act as health educators in the home is proposed as a functional piece of Orem's dependent care agency construct. A new data collection instrument, the Health Education Questionnaire, was developed to explore the conceptual dimensions of an intellectual pre-production phase of health action-taking. Parents' self-reported knowledge and beliefs regarding selected health topics, as well as their perceptions of ego strength and valuing health were proposed as independent factors in dependent care agency related to health education in the home. Methodology included the investigation of reliability using Cronbach's alpha and validation of the agency construct using …

Provenance Of Sands Within The Lower Chesapeake Bay Based On Ilmenite Composition, Edward Augustus Council Iii

OES Theses and Dissertations

Surficial sands deposited in the Chesapeake Bay are a mixture of sands derived from the bay's shorelines, from offshore, and from relict deposits. Direct fluvial input is probably minor except from the James River, which may serve as a local source of sands in the Thimble Shoals area. Sands in the western half of the bay are primarily derived from the erosion of the adjacent shoreline. In contrast, the eastern half of the bay has two major sources of sand. Shoreline erosion is the dominant source north of the town of Eastville, Virginia, while the offshore is the major source …

Short Term Temporal And Spatial Variability Of Phytoplankton In The Elizabeth River, Robert L. O'Reilly

Biological Sciences Theses & Dissertations

This study was designed to evaluate short-term temporal and spatial components of phytoplankton variability within a tidal estuarine system, in reference to natural changes in the local environment.

Multiple water samples were collected weekly from October to December 1984 at 4 stations in different branches, or sections, of the Elizabeth River. Collection of chlorophyll~ data was structured to fit an analysis of variance, while the phytoplankton species and their environmental relationships were analyzed using multivariate techniques.

Lower chlorophyll a concentrations from 0.75 to 2.87 ug/1 were characteristic of the Main Stem and Southern Branch, while higher values of 1.27 …

On A Moving Boundary Problem Of Transitional Ballistics, Jen-Ing G. Hwang

Mathematics & Statistics Theses & Dissertations

A major problem which arises in computer simulation of the firing of a gun weapon is the development of numerical schemes which effectively account for the physics of projectile motion. The chief difficulty is that away from the projectile the calculation is ordinarily accomplished on a fixed numerical grid, whereas due to projectile movement some cells of the grid near the projectile undergo volume changes as the calculation proceeds. A local finite volume scheme is developed which accounts for the expansion or compression of cells fore-and-aft of the projectile. Through the process of numerical experiment, the effectiveness of the scheme …

The Effects Of Nonlinear Damping On The Large Deflection Response Of Structures Subjected To Random Excitation, Chunchu Bhavani Prasad

Mechanical & Aerospace Engineering Theses & Dissertations

Effects of both nonlinear damping and large deflection stiffness are included in the theoretical analysis in an attempt to explain the experimental phenomena of aircraft panels excited at high sound pressure levels; that is the broadening of the strain response peak and the increase in modal frequency. Beams and symmetrically laminated plates subjected to acoustic excitation are considered in the analyses. The excitations are ergodic and Gaussian with zero mean. A polynomial containing both linear and nonlinear damping terms is considered as a damping model. Galerkin's method is used to derive modal equations. Direct equivalent linearization is used to solve …

A Numerical Study Of Three-Dimensional Vortex Breakdown, Robert Edward Spall

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical simulation of vortex breakdown using the time-dependent Navier-Stokes equations was performed. Unlike previous studies, the numerical algorithm, formulated in terms of the velocity and vorticity, was not restricted to axisymmetric flows. Prototype vortices were parameterized in terms of their Reynolds number and Rossby number. Two cases were studied extensively. In one case, a vortex was imbedded in a uniform free stream. In the other case, the axial velocity of the free stream was decelerated in the streamwise direction. For both cases breakdown occurred when the Rossby number was below a critical value. Vortex lines, particle traces and velocity …

Studies Of Radiation Effects In Three High Polymers, Heidi Rene-Mitchell Ries

Physics Theses & Dissertations

Three high polymers, Mylar®, Ultem®, and Kapton®, were irradiated to total doses of 1, 5, and 9.5 gigarad using 1-MeV electrons. The glass transition temperatures (T_g) of the materials before and after irradiation were measured using an AC electrical dissipation factor technique. From the T_g data, it was found that the electron radiation at these total doses results in net chain scissioning in Mylar and net crosslinking in Ultem, while self-mending is predominant in Kapton. The dielectric constant was measured before and after irradiation, but no significant changes due to irradiation were observed. Electron paramagnetic resonance (EPR) …

The Effects Of Task Difficulty On Pupil Diameter In A Choice Reaction Time Task, Coleen Thornton

Psychology Theses & Dissertations

The effects of task difficulty on pupil diameter in a choice reaction time (CRT) task were investigated. Pupil diameter data were collected from 24 subjects using the NASA Langley Research Center oculometer system. Task difficulty was defined by the number of paired stimulus-response alternatives and stimulus-response compatibility. A unique S-R ensemble which required an oculometeric (eye-movement) response and graphic symbols as stimuli was employed in the CRT task. The procedures used replicated Hick's Law for the first time on an oculometer. The S-R compatibility effect was not found to influence this linear trend. The results indicated that pupil diameters for …

The Public Record Office: A Study Of The Creation Of The Office And The Construction Of Its Fireproof Repository, Kathryn A. Miller

History Theses & Dissertations

At the beginning of the nineteenth century Britain's public records were scattered among more than fifty depositories which were overcrowded, unorganized, neglected, and ill-suited to record preservation. The British government was not sympathetic to the condition or the importance of the records. How then did the British government become involved in creating the Public Record Office and building its first fireproof repository? This study takes the form of a chronology based extensively on the records of the Public Record Office, the Office of Works, and the British Sessional Papers.

Although the creation of the Public Record Office was part of …

The Antimicrobial Effectiveness Of Isopropyl Alcohol, Phenylphenol, And Nonphenal Oxyethylene Iodine Complex On Dental Operatory Surfaces, Maureen Anne Lawless

Dental Hygiene Theses & Dissertations

No abstract provided.