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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.

Sins Of The Fathers And Mothers: Relationships Between Parental History Variables And Adult Mmpi Profiles, Kathryn E. Dawson

Psychology Theses & Dissertations

Self-report data on parental history variables--child abuse, father and mother alcoholism, parental mental illness, and father's level of education--were gathered from 469 male and female inpatients at the Florida Mental Health Institute in Tampa, Florida. The Minnesota Multiphasic Personality Inventory (MMPI) was administered within the first 72 hours of admission.

Discriminant function analyses with step-down procedures were performed to determine the effectiveness of the MMPI profiles in discriminating between parental history groups. Each gender was run separately. When comparing patients with no pathological parent history to groups reporting at least one, the chi square was found to be significant for …

The Effects Of Temporospatial Integration On Distance Estimations Of Young And Elderly Adults, Margaret Rowley-Bernicki

Psychology Theses & Dissertations

The effect of discontinuity on temporospati al integration in the accuracy of distance estimations was examined utilizing a slide presentation of a route. Participants were 60 young and 60 elderly adults who were randomly assigned to one of two conditions. The two conditions were determined by whether the subjects viewed the walk in a logically sequenced order or a pre-determined randomized order. Subjects viewed the walk twice and thereafter made a series of distance estimates between a series of preselected landmarks chosen by a different group of young and elderly adults. Additionally, subjects gave self-ratings on a twelve-item questionnaire to …

The Effectiveness Of Oral Health Computer Assisted Instruction On Increasing The Oral Hygiene Status Of Children, Claudia Ann Michalak

Dental Hygiene Theses & Dissertations

This study investigates the effectiveness of computer assisted instruction on the oral hygiene status of children. Over a one month period, as measured by the Personal Hygiene Performance Index, sixty-five fifth grade students participated in one of three intact groups: oral health computer assisted instruction, traditional oral health instruction, or no oral health instructions. Oral health instructions were identical in content for computer assisted and traditional lecture formats. During pretest evaluations, students were presented with a dental kit containing a toothbrush, toothpaste, floss, and an oral health instruction pamphlet. The Personal Hygiene Performance Index was performed on each student prior …

Pre-Natal Learning Needs Perceptions Of Expectant Parents And Childhood Educators, Cynthia Divens Sweeney

Ellmer School of Nursing Theses & Dissertations

The purpose of this study was to examine the differences between the unique learning needs of expectant parents and those perceived by childbirth educators. A purposive sample of 40 expectant parents and ten childbirth educators completed the Expectant Parents Learning Needs Tool (EPLNT) and a demographic inventory developed by the researcher. Subjects were classified into five groups based on their status as first-time fathers, repeat fathers, first-time mothers, repeat mothers, and childbirth educators. Data were analyzed using t-tests for independent samples and an ANOVA for group differences. The results showed significant differences in the learning needs between the expectant parents …

The Stratigraphy Of Late Quaternary Deposits In The Payan Mining District, Narino, Colombia, South America, Richard Alan Barringer

OES Theses and Dissertations

Late Quaternary terrace deposits along the Rio Magui consist of cobble or pebble gravels with thick volcanic ash caps. These gravel terrace deposits unconformably overlie a cemented volcanic tuff (Ananias Formation), and are subdivided into two formations (Antigua and Panambi formations) based on the cobble lithology and size, depth of weathering, geomorphic relationships, and heavy mineral assemblages. Carbon-14 dates from wood suggest that the Antigua fan deposits are older (greater than 40,000 YBP) than the lower Panambi alluvium (less tahn 25,000 YBP) which is restricted to lower terraces within the modern river valleys.

Two separate ash units identified by differences …

Finite Element Methodology For Nonlinear Free And Harmonic Forced Vibrations Of Beam And Plate Structures, Kamolphan Decha-Umphai

Mechanical & Aerospace Engineering Theses & Dissertations

The literature and experiments have shown that nonlinear vibrations produce significant effects in structural analysis, especially the frequency-amplitude-force relation and the analysis of strain. An analysis was developed to predict both the frequency-amplitude-force relation and strains of beam and plate structures. Two finite element methods were developed, namely, the iterative single-mode method (method I) and the multiple-mode method (method II). The harmonic force matrix was developed to analyze nonlinear forced vibrations. Nonlinear free vibration was a special case of the general forced vibration by setting the harmonic force matrix equal to zero. The harmonic force matrix represents the external applied …

Experimental Study Of Shock Wave Interference Heating On A Cylindrical Leading Edge, Allan R. Wieting

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental study of shock wave interference heating on a cylindrical leading edge representative of the cowl of a rectangular hypersonic engine inlet at Mach numbers of 6.3, 6.5, and 8.0 is presented. Stream Reynolds numbers ranged from 0.5 x 10⁶ to 4.9 x 10⁶ per foot and stream total temperature ranged from 2100 °R to 3400 °R. The model consisted of a 3-inch-diameter cylinder and a shock generation wedge articulated to angles of 10, 12.5, and 15 degrees. The primary goal of this study was to obtain a fundamental understanding of the fluid mechanics of shock wave …

Community Development Through Industry And Education Partnerships: An Integrated Evaluability Assessment Of A Cooperative Training Alliance Between Industry And An Urban Community College, Richard E. Witte

Theses and Dissertations in Urban Services - Urban Education

Conceptualizing community college/industry training linkages as unified programs with established evaluable outcomes will allow practical assessment of their value as a community development tool.

The purpose of this study was to conduct an evaluability assessment of the training linkage between Tidewater Community College and Norfolk Naval Shipyard. This alliance was formed to provide professional academic instruction as an element of the shipyard apprentice program. The study established the documented program expectations and the program expectations of state and local community development policy makers, community college leaders and shipyard management. The study evaluated all identified expectations for compatibility across partnership interests, …

A Simple Numerical Model For The Study Of Baroclinic Estuarine Shelf Interactions, Thomas J. Berger

OES Theses and Dissertations

A one and a half layer nonlinear f-plane numerical model was used to study estuarine-shelf interactions. The single active layer covered a domain consisting of a 100 km long by 20 km wide channel discharging onto a 100 km wide by 300 km long shelf. Channel and "western” shelf boundaries were no-slip, "eastern" or oceanic boundary was free-slip and "northern" and "southern" shelf boundaries were open. The channel was forced with a constant inflow velocity spun up from 2 cm s^-1 to 27 cm s^-1over five days. The model initial conditions were a flat interface at …

Groin-Associated Rip Currents Measured Using A New Digital Current Meter, Dennis L. Lundberg

OES Theses and Dissertations

Rip currents have often been noted in physical model studies of groins and their effectiveness. Nevertheless, detailed field investigations of rip currents along a groin wall have not been heretofore conducted. A new digital current meter system was designed and built to study the groin-associated rip currents in a test groin compartment at Willoughby Spit, Norfolk, VA. Six ducted impeller current meters are controlled by a data acquisition system that utilizes an onboard microprocessor and solid state memory. The new system provides high quality data on horizontal water velocities associated with wave action. The velocities stored are time mean velocities …

The Relationship Of Upwelling To Mussel Production In The Rias On The Western Coast Of Spain, Jack O. Blanton, Kenneth R. Tenore, F. Castillejo, Larry P. Atkinson, Franklin B. Schwing, Amy Lavin

CCPO Publications

We have calculated an upwelling index for each month over a 17-year period (1969-1985) for a point off the western coast of Spain. We interpret April through September values of the index to indicate the flux of nitrate-rich water in the Spanish Rias. The index representing the 6-month upwelling series has been correlated with an index representing the conditions of mussels grown during that season on rafts in Ria de Arosa. Two seasons represent extreme upwelling conditions over the 17-year sampling period: 1977 when the upwelling index was the highest, and 1983 when it was the lowest. A comparison of …

Coupled Bending-Torsion Steady-State Response Of Pretwisted, Nonuniform Rotating Beams Using A Transfer-Matrix Method, Carl E. Gray Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Using the Newtonian method, the equations of motion are developed for the coupled bending-torsion steady-state response of beams rotating at constant angular velocity in a fixed plane. The resulting equations are valid to first order strain-displacement relationships for a long beam with all other nonlinear terms retained. In addition, the equations are valid for beams with the mass centroidal axis offset (eccentric) from the elastic axis, nonuniform mass and section properties, and variable twist. The solution of these coupled, nonlinear, nonhomogeneous, differential equations is obtained by modifying a Hunter linear second-order transfer-matrix solution procedure to solve the nonlinear differential equations …

Shoreward Intrusion Of Upper Gulf Stream Water Onto The United States Southeastern Continental Shelf, Lie-Yauw Oey, Larry P. Atkinson, Jackson O. Blanton

CCPO Publications

In winter, cooling of the South Atlantic Bight continental shelf water results in higher density in the middle shelf region relative to the shelf-break region where the western flank of the Gulf Stream flows. Shoreward, estuarine-like intrusion of the upper Gulf Stream water in the presence of such a positive onshore density gradient is then possible through advective processes triggered either by the meander of the Stream or onshore Ekman transports by southward wind stresses. Repeated cross-shelf hydrographic transects were conducted from 10 January through 30 January 1986 to more closely study this intrusion process. These observations show many features …

Validation Of The Otolith Increment Aging Technique For Striped Bass, Morone Saxatilis, Larvae Reared Under Suboptimal Feeding Conditions, Cynthia Jones, Edward B. Brothers

OES Faculty Publications

Striped bass, Morone saxatilis, larvae were reared in the laboratory for 97 days to validate the otolith increment aging technique for this species. Otolith-increment deposition rates were determined under optimal laboratory conditions for growth and under three conditions of restricted feeding and using both light and scanning electron microscopy (SEM). Under optimal laboratory conditions. increments were deposited daily from the fourth day after hatching through the first 2 months of life and were discernible with the light microscope. For larvae reared under restricted feeding regimes and readings done with the light microscope, counts did not reflect true age. Counts …

Is Growth Of Eelgrass Nitrogen Limited? A Numerical Simulation Of The Effects Of Light And Nitrogen On The Growth Dynamics Of Zostera Marina, Richard C. Zimmerman, Robert D. Smith, Randall S. Alberte

OES Faculty Publications

A numerical model of nitrogen uptake and growth was developed for the temperate seagrass Zostera marina L. Goals were to evaluate the relative effects of light and nitrogen availability on nitrogen uptake and partitioning between leaf and root tissue, and to estimate nitrogen concentrations in the sedment and water column required to saturate growth. Steady-state predictions are quite robust with respect to a range of parameter values justified by available data The calculations indicated that roots are probably more important in overall nitrogen acquisition in most light and nitrogen environments encountered in situ, but may contribute less than 50 …

Comment On "Orientation, Alignment, And Hyperfine Effects On Dissociation Of Diatomic Molecules To Open Shell Atoms", Mark D. Havey, Linda L. Vahala

Electrical & Computer Engineering Faculty Publications

A recent paper in this journal [Y. B. Band e t a l., J. Chem. Phys. 8 4, 3762 (1986)] reported parameters describing orientation and alignment produced, in an axial recoil limit, by one photondissociation of diatomic molecules. Reported also were values, applicable to the resonance transitions of the alkali atoms, for orientation and alignment depolarization coefficients. Most of the numerical values reported for the coefficients were incorrect, in some cases by as much as a factor of 2. We report a tabulation of correct depolarization coefficients applicable to the resonance transitions of common alkali isotopes. Further, the coefficients …

Acceleration Of Nutrient Uptake By Phytoplankton In A Coastal Upwelling Ecosystem: A Modeling Analysis, Richard C. Zimmerman, James N. Kremer, Richard C. Dugdale

OES Faculty Publications

Studies of upwelling centers in the eastern Pacific suggest that maximum rates of nitrate uptake (light and nutrient saturated) increase, or shift-up, as newly upwelled water moves downstream. The rate of shift-up appears to be related to irradiance and the ambient concentration of limiting nutrient at the time of upwelling. A mathematical model was developed to evaluate effects of irradiance and initial nitrate concentration on temporal patterns of shift-up and subsequent time scales of nutrient utilization over a range of simulated upwelling conditions. When rates consistent with field studies were used, complete shift-up was possible only under certain conditions, and …

The Hydrogeology Of Nags Head Woods, Dare County, North Carolina, Janet Salyer Emry

OES Theses and Dissertations

Nags Head Woods, a coastal maritime forest located on a barrier island in eastern North Carolina, stabilizes a back-barrier dune system bordering a tidal marsh. The purpose of this study is to provide basic information about the groundwater geology in Nags Head Woods and to predict the effects upon water levels due to municipal pumping of Fresh Pond, a large lake near the center of the island.

Clean, fine-to-medium sands dominate the top of the surficial (water table) aquifer, underlain by silty fine-to-coarse sands at -4 m elevation. A silty clay bed of very low permeability is present at -12 …

A Study Of The Education For Employment Program Henrico County, Virginia As It Relates To The County Dropout Rate, 1979-1986, Cliff Fink

OTS Master's Level Projects & Papers

The problem of this study was to conduct a countywide survey to identify and analyze the E.F.E. Program in Henrico County as it relates to what effect this program had on the total county dropout rate since 1979.

Efficiency Versus Effectiveness: The Teacher Versus The Computer In Classroom Education, Juanita V. Smith

OTS Master's Level Projects & Papers

This study presented the following hypothesis: H1 There is a significant difference in the performance of Business Computer Application students who are taught Word Processing by packaged tutorial software and Business Computer Application students who are taught Word Processing by teacher-assisted method as measured by Word Processing Unit Test.

A Study To Determine Desired Life/Work Skills Not Acquired By Adults During Formal School Training, N. Gail Mcclure

OTS Master's Level Projects & Papers

This problem was answered by focusing on the following questions: 1. Which topics or subjects do adults feel that they are lacking to improve either their personal or professional lives? 2. Which topics or subjects were not available to them during their formal school training?

Depositional And Diagenetic History Of The Middle Ordovician Carbonates Of The Shenandoah Valley, Northern Virginia, Lynn Ellen Weyenberg

OES Theses and Dissertations

An examination of the Middle Ordovician carbonates in northwest Virginia has revealed a particularly sensitive record of deposition and subsidence. Two-hundred acetate peels from six measured stratigraphic sections in Shenandoah County, Virginia were examined to interpret the depositional and diagenetic history. Two major lithofacies have been recognized within the New Market Limestone and three have been recognized in the Lincolnshire Formation. These five lithofacies represent an overall transgressive sequence. This transgression was not uniform but paused several times to allow carbonate deposition to reach sea-level. These shoaling events suggest a slowly subsiding basin in this region. The carbonate rocks within …