Physical Sciences and Mathematics Commons^™

An Experimental And Theoretical Study Of The Flow Phenomena Within A Vortex Sink Rate Sensor, Dashrath Khodidas Patel

Mechanical & Aerospace Engineering Theses & Dissertations

The objective of this investigation was to obtain a detailed description of the flow field within a vortex sink rate sensor and to observe the influence of viscous effects on its performance.

The sensor basically consists of a vortex chamber and a sink tube. The vortex chamber consists of two circular coaxial disks held apart, at their periphery, by a porous coupling. One circular disk has an opening to permit the mounting of the sink tube, in such a manner that the vortex chamber as well as the sink tube have a common axis of rotation.

Air was supplied radially …

Observations On The Distribution And Composition Of Zooplankton In Portions Of The Intracoastal Waterway, Virginia, O. Clair Hillard Jr.

Biological Sciences Theses & Dissertations

Five stations were established in the Southern Branch of the Elizabeth River, the Dismal Swamp Canal, the Albemarle and Chesapeake Canal and the North Landing River. Representative samples of zooplankton were taken from October 1971 to June 1972. A. total of 57 species were identified and discussions regarding seasonal distribution in relation to physical factors and circulation are presented.

The composition of the zooplankton was found to fluctuate greatly due to the variables characteristic of the study area. The combined effect of tidal flow with freshwater input in conjunction with drainage from the Great Dismal Swamp, results in isolated populations …

The Use Of Color Infrared Aerial Photography In Determining Salt Marsh Vegetation And Delimiting Man-Made Structures Of Lynnhaven Bay, Virginia, Robert E. Holman Lll

Biological Sciences Theses & Dissertations

Color infrared aerial photography was found to be superior to color aerial photography in an ecological study of Lynnhaven Bay, Virginia. The research was divided into three phases: 1) determination of the feasibility of correlating color infrared aerial photography with wetland species composition and zonation patterns, 2) determination of the accuracy of the aerial interpretation and problems related to the aerial method used, and 3) comparison of developed with undeveloped areas along Lynnhaven Bay's shoreline.

Wetland species composition and zonation patterns of major cones were correlated with aerial infrared photography and resulted in a high degree of accuracy. Problems with …

An Ecological Study Of The Craney Island Disposal Area In Hampton Roads, Virginia, David Wallace Laist

Biological Sciences Theses & Dissertations

A one year ecological study was conducted on the Craney Island Disposal Area in Hampton Roads, Virginia. This study attempted to identify the flora and fauna inhabiting the spoil deposits and trace the development of communities from the time of deposition through the initial stages of succession.

One hundred and ninety-two species were identified including 48 vascular plants, 66 insects, 48 birds, 18 species of algae, 4 crustaceans, and 8 vertebrates. The study area was divided into six zones based on substrate characteristics and species composition. The successional patterns and biotic interactions within each zone were discussed.

An Investigation Of Littoral Transport Between Virginia Beach And Sandbridge, Virginia, Richard C. Cunningham Jr.

OES Theses and Dissertations

A method for calculating littoral transport, direct determination of the sediment flux, has been proposed and evaluated. Three sampling stations, located between Virginia Beach and Sandbridge, Virginia, were occupied for a period of thirteen months (September, 1972 to September, 1973). Measurements include velocity of the littoral current, cross-sectional area of the surf zone, and in situ samples of suspended and bottom sediment load. Observations of sea and atmospheric conditions were obtained. Two ways of calculating littoral transport were derived from the same basic method, thus two sets of transport values were generated. Two annual littoral transport values were calculated by …

Studies On The Causes Of Tree Distribution In A Forest Type In The Dismal Swamp National Wildlife Refuge, Thomas A. Janszen

Biological Sciences Theses & Dissertations

Vegetational composition and environmental parameters were analyzed in a forest type of the Dismal Swamp. A 0.5 ha forest stand was divided into 200 5 x 5 meter contiguous quadrats and the tree size classes were precisely mapped. Fifty soil samples were analyzed for texture, pH, and major nutrients. A topographic map was constructed with precision to 0.01 ft. Analysis of variance tests showed non-randomness to exist in soil texture and nutrient content while homogeneity tests showed non-randomness in distribution of some woody species. Factor analysis indicated no significant correlations between soil quality, topography, and woody species. Findings indicate that …

Comments On 'Fluctuations In Guiding Center Plasma In Two Dimensions', George Vahala, Linda L. Vahala, David Montgomery, Glenn Joyce

Electrical & Computer Engineering Faculty Publications

It is stated that the principal result of the paper by Taylor and Thompson (see abstr. A14511 of 1973) on autocorrelations in density for the electrostatic guiding center plasma in two dimensions is wrong owing to an incorrect integration. It is further stated that there is no meaningful distinction between an `interaction cutoff' and a `fluctuation cutoff'.

The Economic Aspects Of Water Pollution By Naval Vessels In The Port Of Charleston, South Carolina, John Edward O'Connor

Economics Theses & Dissertations

No abstract provided.

Evolution Of Platt Shoals Northern North Carolina Shelf: Inferences From Areal Geology, Philip C. Sears

OES Theses and Dissertations

The evolution of Platt Shoals, a complex ridge and trough system on the south side of the Albemarle Shelf Valley, was determined and the modern hydraulic regime was inferred. The methods used were surficial grain size, 11 vibracores, seismic profiling and bathymetric maps. Platt Shoals developed in a three step process. The first, step was the formation of a substrate of late Pleistocene regressive deposits from 15,000 to 30,000 yr B. P. The second step, occurring approximately 11,000 yr B. P., was the formation of estuary mouth shoals of the ancestral Albemarle River. Between 4,4.00 to 5,000 yr B. P., …

A Comparative Limnological Survey Of Brackish-Water Lake And A Fresh-Water Lake At Mount Trashmore, Virginia Beach, Virginia, Gene Ramon Cocke

Biological Sciences Theses & Dissertations

No abstract.

Particle Size Distribution And Small-Scale Bed-Forms On Sand Waves, Chesapeake Bay Entrance, Virginia, John T. Wells

OES Theses and Dissertations

The relationship between sediment texture and topography has been studied along five series of sand waves in Chesapeake Bay entrance, Virginia. Results indicate that two types of sand waves with reference to mean grain size are present: sand waves with coarse sediment on crests and fine in troughs, and sand waves with fine sediment on crests and coarse in troughs. Asymmetrical, migrating sand waves exhibit the first type; near-symmetrical, non-migrating sand waves exhibit the second type. In general, bimodal sediment is present on crests of migrating sand waves and in troughs of stationary sand waves. There is a progressive decrease …

Food And Feeding Of Fishes From Magothy Bay, Virginia, Joseph J. Kimmel

OES Theses and Dissertations

No abstract provided.

Phycosociology Of The Estuarine Eulittoral Of Smith Island Virginia: A Quantitative Approach To Seasonal Periodicity, William M. Willis

OES Theses and Dissertations

Seasonal periodicity of benthic algae of the estuarine eulittoral of Smith Island, Virginia, (37°07’55” N, 75°55’ W), has been investigated on a qualitative and quantitative basis. Forty-three taxa of benthic eucaryiotic algae were found to be present; of these, twenty-one were quantitatively significant at least once during the course of the study. Five species represent additions to the Virginia flora, and, at the same time, also represent southern extensions of the known U.S. east coast range. The range of three other species has been extended, though they are not new to Virginia.

Review of the literature suggests two models of …

Complexes Of The 2,2'-Bisacylhydrazide Of 3,3'-Bipyridine And The Dipicolinic Acid Dihydrazide Ligand Systems, William Leo Johnson Iii

Chemistry & Biochemistry Theses & Dissertations

The copper(II) complexes of the picolinic acid bydrazide (PH), the dipicolinic acid dibydrazide (DPH), and the 2,2'-bisacylbydrazide of 3,3'-bipyridine (DAR) ligand systems have been prepared and have been characterized by infrared spectroscopy. Coordination has been proposed to occur between the terminal amine, the amide nitrogen, and the ring nitrogen in each of the respective complexes.

Evidence for the loss of the amide hydrogen upon complexation of PH, DPH, and DAH with copper(II) has been observed by the n.m.r. study of the zinc(II) complexes of the PH and DAH ligand systems. This is in support of the structures proposed above for …

A Zooplankton Study Of Stumpy Lake, Virginia Beach, Virginia, Jose E. Hernandez

Biological Sciences Theses & Dissertations

A one year study was made of the zooplankton composition in Stumpy lake, a reservoir in the city of Virginia Beach, Virginia. Quantitative and qualitative -parameters were investigated under field conditions. The analysis of the data presents information on the monthly dynamics or the zooplankton and other fluctuations in the lake environment. It is the intention or this study to emphasize the seasonal changes in the zooplankton community and their relationship to the ecological factors responsible for these variations.

Investigation Of The Halocline Structure In Lower Chesapeake Bay, Samuel Bowen Heltzel

OES Theses and Dissertations

A portion of the Chesapeake Bay from 37°20’N latitude to the entrance was investigated to determine the halocline structure, the effects on this structure through the tidal sequence, and seasonal variations. A determination of the stage of slack water during which maximum extension of the halocline occurred was also made. This was accomplished by looking at the salinity distribution at the halocline upper limit, the mean depth to the halocline, and seasonal salinity contours drawn for tidal increments. By comparing salinity/depth gradients and salinity-depth vertical profiles, an attempt was made to relate seasonal and tidal variations to the halocline structure. …

A Seasonal Distributional Survey Of The Epiphytic Diatoms Of The Outer Banks Region Of North Carolina With Respect To Temperature And Salinity, Charles Welles Belin Jr.

OES Theses and Dissertations

This study was initiated to investigate epiphytic diatoms at selected stations along the North Carolina coast and bay region. The relationships between these organisms and the season of the year and salinity and temperature of the water in which they were found are considered. The special affinity between the epiphytic diatoms and their host plants is also discussed. The specific data were analyzed statistically via linear correlation coefficients, graphs of least squares-best fit, and multiple linear regression analysis.

From the statistical tests, it was found that the mean number of epiphytic diatoms shows a significant multiple linear regression with respect …

Effect Of Air Bubble Solution On Air-Sea Gas Exchange, Larry P. Atkinson

CCPO Publications

Recent data on ambient wave generated oceanic bubble spectra (Medwin, 1970) permit the calculation of the influence of bubble solution on air-sea gas exchange. Schulkin's formula is used to estimate the depth variation of bubbles, and a square law is used to estimate the increase of bubble volume with wind speed. Calculations indicate that bubble solution can be a very significant factor in gas exchange. Bubble solution enhances gas input and retards degassing of the water column. Preliminary data show a lag time of about 5 hours in the response of the water column to an atmospheric pressure change.

Seismic Refraction Study Of Post-Pliocene Stratigraphy, Dismal Swamp, Virginia, William Brian Fraser

OES Theses and Dissertations

This study examines Pliocene-Pleistocene lithostratigraphy and the Yorktown unconformity within the Dismal Swamp by means of remote sensing analysis, Wyrobek-Gardner seismic refraction profiling and split-spoon coring. Pre-Sangamon fluvial/tidal channel deposits are not present and the Yorktown unconformity dips irregularly southeastward at 0.35 meters/kilometer (2 feet/mile) from a high at 4 meters above sea level to a low of -1 meter (+12 to -2 ft) below sea level. The marker velocity for the Yorktown Formation is 1600 mps (5250 fps) and regression of seismic depths of the Yorktown Formation with corresponding split-spoon depths yields a high correlation. Short line upper layer …

Air Bubbles In An Oceanic Mixed Layer: Effect On Gas Concentrations And Air-Sea Gas Exchange, Larry P. Atkinson

CCPO Publications

This thesis attempts to determine the effect of air bubbles that are entrapped into the surface layers of the ocean by breaking waves on gas concentrations in the ocean and gas exchange across the air-sea interface. N₂ and Ar data gathered during the Hudson-70 expedition produced indications of the magnitude and nature of the effect. A mathematical model is developed that equates the input of gas via bubble solution with the vertical eddy diffusion. Published values for bubble spectra and solution rates are used and assumptions are made concerning the effect of wind on bubble spectra. The model predicts …

Morphologic Time Series From A Submarine Sand Ridge On The South Virginia Coast, John F. Mchone Jr.

OES Theses and Dissertations

Submarine sand ridges several km long locally merge southward into the U. S. Atlantic coastline. Shallow (< 8m) observations of -such a ridge at False Cape, Virginia, favor a modern hydraulic origin. Time series maps show the ridge to be paralleled by a landward trough of approximately equal volume. Ridge flanks are usually steeper on the trough side.

Northeasterly winds and waves generate a coast-parallel current which funnels southward into the trough scouring it out and providing sediments for ridge aggradation. The current may be organized as a helical flow cell or cells. Bottom currents converge southward along the ridge crest causing landward transport of traction load along the crest. The trough current eventually breaches the confining ridge at the head of the trough, cutting saddles with steeper seaward slopes and producing outlying sediment fans.

The ridge and trough rest obliquely …

The Synthesis And Characterization Of The 2,2'-Bisacylazide Of 3,3'-Bipyridine, Magdy Adly Guirguis El-Fayoumy

Chemistry & Biochemistry Theses & Dissertations

The primary objective of this research has been the synthesis and characterization of a new heterocyclic diacylazide, the 2,2'-bisacylazide of 3,3'-bipyridine 19. This heterocyclic diacylazide has been successfully synthesized from the phenanthrolin-5,6-dione 14, and examined with regard to its.thermal and photolytic decomposition.

Thermal decomposition of this disacylazide seems to go by a double-barreled Curtius rearrangement leading to a series of pyridonaphthyridinone (20) compounds such as 22 and 29.

An initial study of the photolysis of this bisacylazide has been initiated to examine the possible formation of nitrene-type intermediates.

Phytoplankton Distribution In Waters Off The Northeastern Coast Of The United States, Sharon H. Craft

Biological Sciences Theses & Dissertations

Abstract unavailable.

Surface Water Turbidity In The Entrance To Chesapeake Bay, Virginia, James R. Melchor

OES Theses and Dissertations

Seasonal and spatial variations in the surface water turbidity across the entrance to Chesapeake Bay, Virginia, have been monitored with an optical transmissometer for one year. The data indicate a suspended-sediment gradient across the entrance with higher turbidity on the south side. This condition suggests that the flooding and ebbing tidal currents are influenced by Coriolis force. Clearer ocean water is introduced into the bay on the north side; whereas highly turbid water from the major drainage systems exits on the south side. A salinity gradient with18 0/00 on the south side of the bay and approximately 32 0/00 on …

Determination Of Nutrient Levels And Proposed Predictive Models For Phosphate In The Lafayette River, Norfolk, Virginia, John R. Montgomery

OES Theses and Dissertations

The Lafayette River, an Urban, well-mixed estuarine embayment, was sampled from October, 1970 to January, 1972 for phosphate, nitrate, nitrite, oxygen, water temperature and salinity. The mean values found for these samples were: oxygen saturation from 69% to 106% nitrate from 0 to 4 microgram-atoms per liter, and salinity from 13 ‰ to 24 ‰. The mouth of the Elizabeth River to Hampton Roads as also sampled from May, 1971 to August, 1971. The Lafayette and Elizabeth Rivers were also sampled over a 24 hour period in the summer of 1971 and the Lafayette River again in the winter of …

Diurnal Studies At A Station On An Urban Estuary In Norfolk, Virginia, Burton Marc Golue

Biological Sciences Theses & Dissertations

No abstract.

A Physical Hydrographic Study Of The Lafayette River, E. Glenn White

OES Theses and Dissertations

A basic investigation of the physical ~properties, temperature, density and current velocity, in the Lafayette River is presented. Graphs of the observations indicata a difference in salinity, density and current velocity- distributions after moderate to heavy rains from the graphs during a dry period. The changes in distribution indicate a change in the classification of the estuary from a type B/C, partially mixed estuary, to a type D, sectionally homogeneous estuary. The estuary is predominantly a well-mixed or sectionally homogeneous estuary.

Changes in salinity, temperature, density and current velocity over tidal cycles are discussed as well as tidal height data. …

The Influence Of The Summer Thermocline On Estuarine Classification In The Chesapeake Bay Entrance, William G. Weiss Jr.

OES Theses and Dissertations

The temperature, salinity, and sigma-t of 397 oceanographic stations taken in the entrance to Chesapeake Bay were plotted using a simple interpolation formula by the lBM 1130 computer. Each station was catalogued by position, tidal stage, season, and estuarine classification. Results indicated increased stratification during the ebb phase of all entrance stations regardless of season. Partially mixed conditions predominate. The influence of the summer thermocline on the stratification caused a slight increase in the summer stratification mean. However, statistical tests showed this summer increase to be insignificant at the 95% level. Detailed classification of tidal stage by estuarine type for …

An Evaluation Of A Stable Isotope Of Dysprosium For Labeling And Tracing Sedimentary Particles, Charles Glenn Boone

OES Theses and Dissertations

An evaluation of the application of dysprosium oxide as a tracer coating to surface label sedimentary particles is made. Physical and chemical properties of the labeled sand are studied. Effective diameters and settling properties of the tracer sand are compared with unlabeled sand. A total of 8.51 kg of labeled sand was placed on the beach at Camp Pendleton. Dispersal patterns obtained 1 and 4 hours after tracer injection indicate a general down current mean tracer migration rate of 0.21 cm/sec (0.42ft/sec). An absolute detection limit of 4 or 5 parts per 100,000 and a real detection limit, after field …

An Application Of Spectroscopic Techniques To The Measurement Of Electron Density And Temperature In A Brush Cathode Plasma, Ramabhai M. Patel

Physics Theses & Dissertations

A brief review of the Langmuir probe, microwave and spectroscopic techniques most commonly used to make measurements .of plasma electron temperature and density is presented. Of these various methods, certain spectroscopic methods are applied to the measurements of electron density and temperature in a helium brush cathode plasma. The density measurement is based on the manner in which a series of Stark broadened spectral lines merges into an apparent continuum before the normal series limit is reached. This approach met with only limited success in that the density could be determined only by extrapolating the data obtained. Primarily because of …