Physical Sciences and Mathematics Commons^™

The Effects Of Varying Fresh Water Discharge On Dispersion In An Estuarine Hydraulic Model Of The Lafayette River, Norfolk, Virginia, Michael J. Jugan

OES Theses and Dissertations

Three experimental tests were conducted in the Lafayette River branch of the Chesapeake Bay Hydraulic Model, each successive test with an increase in the amount of fresh water discharged into the head of the river. This was done to study the response from varying river discharge on mixing parameters including the longitudinal dispersion coefficient (E).

The model generated a tide of constant range and period. Batch releases of Rhodamine WT dye were made in the model and sampled throughout the river for ten tidal cycles. Samples were taken simultaneously at selected high and low water slack.

The calculation of the …

Some Effects Of The Polychaete Nereis Succinea Frey And Leukart 1847 On The Distribution Of Copper Cadmium And Zinc In Sediments And Water, Gabriela Kitzig August

OES Theses and Dissertations

Two laboratory experiments, each lasting 216 hours, were conducted in order to determine the effects of a burrowing polychaete, Nereis succinea Frey and Leukart, 1847, on the distribution of copper, cadmium, and zinc in sediments and water in environmentally controlled microcosms. Dissolved metal concentrations in microcosms containing worms (experimental) decreased more rapidly than in microcosms without worms (controls). From 72 hours to 216 hours, suspended metal concentrations in experimental microcosms increased while concentrations in controls remained relatively constant. Sediment cadmium concentrations in experimental microcosms increased more over time than in controls. Polychaetes accumulated significant amounts of all three metals. These …

Factors Effecting Phytoplankton Assemblages In The Lafayette River Estuary, Laurie Ann Kalenak

OES Theses and Dissertations

Chemical and physical parameters were measured with phytoplankton species composition and abundance in the Lafayette River from August to October 1981. Stations located in four distinct areas of the river were statistically analyzed to determine data relationships. Environmental factors considered as potentially influencing the presence and numbers of phytoplankton were salinity, temperature, Secchi depth, tidal phase, orthophosphate, combined nitrates and nitrites, ammonia, and reactive silicates.

The River mouth had higher salinity and nutrient values, with lower temperatures than the other river sections. Diatoms were the dominant cells in this section of the River. At mid-river, salinity and nutrient concentrations decreased, …

The Marine Geochemistry Of Selenium, Kazufumi Takayanagi

OES Theses and Dissertations

A fluorometric method for the determination of Se (IV) and total selenium in natural waters has been developed and optimized. The detection limit is about 20 pM for both analyses using a one liter sample. The precisions were about 2 % at 338 pM for Se (IV) and at 234 pM for total selenium.

The concentrations of both total selenium and Se (IV) decreased with increasing salinity in the surface waters of the James River and southern Chesapeake Bay. While total selenium seemed to exhibit conservative behavior at salinities above 0.36 ('o)/oo, Se (IV) was apparently removed during estuarine mixing. …

The Effects Of Dredged Material (Suspended Solid Phase) On The Hatching Success Of Spot Eggs (Leiostomus Xanturus), Meryl A. Masters

OES Theses and Dissertations

A 24-hour static bioassay was performed with the suspended solid phase of bottom sediment from a highly industrialized river utilizing eggs of the spot, Leiostomus xanthurus. Hatching success was measured at four concentrations of elutriates prepared from sediment obtained from the confluence of the eastern and southern branches of the Elizabeth River adjacent to the Norfolk Shipbuilding and Drydock in Norfolk, Virginia. Test results indicated no significant effect on hatching success at any of the four test concentrations.

Environmental Influence On The Migratory Behavior Of The Brown Shrimp In Pamlico Sound North Carolina, Michael Andrew Matylewich

OES Theses and Dissertations

Environmental conditions in the nursery areas during times of development affect the migratory behavior of the brown shrimp (Penaeus aztecus) by influencing growth and natural mortality. A linearized logistic model and a multiple linear model are used to relate environmental factors (week number, water temperature, salinity, air temperature, precipitation, net heating degree days, river discharge) to the cumulative proportion of catch and catch-per-unit-effort, respectively. Multiple regression analysis yielded equations containing the week number, the water temperature and an interaction term as the independent variables. Predictions of total annual yield and total annual catch-per-unit-effort are made using the migratory …

Analysis Of Heavy Minerals In Arenaceous Lutites From The Northern Canada Basin, Arctic Ocean, Kim Zauderer

OES Theses and Dissertations

Heavy minerals from arenaceous lutites in three widely spaced cores from the northern Canada Basin were analyzed for the first time to determine the provenance of these sediments. The abundant minerals (sp. gr. == 2.70) in decreasing order for most samples were detrital carbonate, micas, clinoamphibole, clinopyroxene, garnet, epidote, tourmaline, and chlorite. The majority of pyroxene grains were etched. Sedimentary sources dominated and metamorphic and igneous sources were important but secondary. The northern Canada Arctic Archipelago and northern Greenland is proposed as the provenance for the heavy minerals in the arenaceous lutites for at least the past three million years. …

Morphological Variation Of The Foraminifer Elphidium Excavatum (Terquem) On Crumps Bank And Willoughby Bank, Chesapeake Bay, Virginia, Pamela Kay Painter

OES Theses and Dissertations

Six variants of the highly variable foraminiferal species, Elphidium excavatum (Terquem) were recognized in the Crumps Bank and Willoughby Bank areas of the southern Chesapeake Bay. Measurements of the size of the test, the number of chambers, the number of umbilical bosses, and the number and average length of the sutural bridges on the last formed chamber, and opaqueness or translucence of the test were made on 30 specimens from each of 36 stations selected for differences in environmental parameters. The measurements were statistically analyzed by discriminant analysis to test the hypothesis that the variants are distinct morphotypes and to …

Modeling Charge Diffusion From Proton-Induced Ionization Tracks In Silicon Photodiode Arrays, Lee Cole Smith

Physics Theses & Dissertations

We are modeling the combined problem of generation and collection of charge carriers created during passage of energetic protons through a silicon photodiode array. We have also experimentally obtained pulse-height distributions of noise charge collected during exposure of a Digicon-type diode array to 21 and 75 MeV protons. It is shown that the magnitude of charge collected by a diode from each proton event is determined not only by diffusion, but by statistical considerations involving the ionization process itself. Utilizing analytical solutions to the diffusion equation for transport of minority carriers, together with the Vavilov-Landau theory of energy-loss fluctuations in …

Stratigraphy And Depositional Environments Of A Late Pleistocene Barrier Island Complex, Southeastern Virginia, Alan K. Jasper

OES Theses and Dissertations

The Norfolk, Kempsville, and Sand Bridge Formations beneath the HIckory Scarp of southeastern Virginia are reinterpreted as representing one glacio-eustatic transgressive cycle. The timing of this transgressive event is set during the earliest Wisconsinan. The formations were previously interpreted as unconformable overlying one another. The Norfolk-Kempsville unconformity is actually a diagenetic boundary. Evidence is presented which indicates that the Kempsville Scarp area should be reduced to member status or dropped entirely.

Analysis Of Organic N-Chloramines In Chlorinated Drinking Water, John Po Wen Yang

Chemistry & Biochemistry Theses & Dissertations

This thesis describes the development of a sensitive method for the separation and quantitation of organic N-chloramines in chlorinated tap water. 5-Dimethylaminonaphthalene- l-sulfinic acid has been synthesized and characterized. It yields highly fluorescent dansyl derivatives on reaction with N-chloramines. Conditions of the derivatization were optimized for the detection of N-chloropiperidine at concentrations in aqueous solution of 10^-7 M. The technique gives a quantity of derivative which is proportional to the concentration of chloramine present over the range examined (10^-7 M to 10^-4 M). High pressure liquid chromatographic separation of dansyl derivatives of amines and amino acids has …

The Effects Of Kepone On The Estuarine Copepod Acartia Tonsa, Judith Marie Wilson

Biological Sciences Theses & Dissertations

Due to the contamination of a 113 km reach of the James River, Kepone poses a serious environmental threat to the Chesapeake Bay. The purpose of the study is to determine the acutely toxic and sublethal levels of kepone for the copepod Acartia tonsa, and to investigate what effects those levels may have on filtration rates.

Kepone was determined to be acutely toxic to A. tonsa, with a 96 hour LC50 of 4.96 ug/1. Dunaliella tertiolecta was selected as the food source for the grazing experiments. Kepone concentrations of 0.046 ug/1 significantly (0.05 level) reduced the flltering rate …

Absorption Coefficients Of Ozone At Low Temperature In The Visible Region, Hessameddin Ghiassi

Physics Theses & Dissertations

The temperature dependence of absorption coefficients of ozone was studied between 7567 Å and 4630 Å . When the gas was cooled from room temperature to -108° C, an overall increase in the absorption coefficients was noticed. The maximum increase of 5% occurred at λ = 6020 Å. In general, the absorption is linearly dependent on temperature.

A Laboratory Study Of Nongenetic Embryonic Adaptation To Salinity And Its Subsequent Effects Upon Larval Development Of The Grass Shrimp Palaemonetes Pugio Holthius, Paul Jay Anninos

OES Theses and Dissertations

Fertilized embryos of the grass shrimp Palamonetes pugio Holthuis (Decapoda; Caridea) were exposed to two levels of salinity [5 ppt (exposed) and 20 ppt (control)] during incubation to determine the extent to which embryonic adaptation influences subsequent larval development. Larval response to embryonic exposure was measured at three salinities (5 ppt, 10 ppt, and 20 ppt) as the fraction of larvae surviving to metamorphosis and the duration (in days) of larval development. The survival rate of larvae hatched from control, or non-adapted, embryos was significantly influenced by rearing salinity. The differences in survival of pre-adapted larvae (exposed group), however, were …

Ortho Cyclization Reactions Of Catecholamines, Robert Lee Hudkins

Chemistry & Biochemistry Theses & Dissertations

A study was undertaken to examine the potential for ortho cyclization associated with the synthesis of 1,2,3,4,-tetrahydroisoquinolines using the Pictet-Spengler reaction. Specif1cally, the condensation of the biogenic amines, dopamine, norepinephrine and epinephrine were carefully examined in light of current literature and the facility and extent of ortho cyclization in each case. The para isomers of these three biogenic amine condensation products were isolated and characterized, while only the ortho isomer derived from dopamine was found stable and could be isolated, and structurally identified. These studies demonstrate that a second cyclization product does, in fact, form in each instance and that …

The Regioselective 3-Alkylation Of Piperidine, Richard Dunn Todd

Chemistry & Biochemistry Theses & Dissertations

The compounds: 3-allylpiperidine, 3-ethylpiperidine and 3-n-butylpiperidine have been synthesized by regioselectively alkylating the three position of piperidine. Piperidine was converted to N-chloropiperidine and then dehydrohalogenated to produce Δ¹-piperideine. The enamide anion was generated by adding solutions of Δ¹-piperideine to ethylmagnesium bromide or lithium diisopropylamide. Addition of alkylhalides produced 3-alkyl- Δ¹-piperideine which could be reduced or alkyllithiated to give 3-alkylpiperidines or 2,3-dialkylpiperidines respectively.

The yields of products were low and the reaction generated a continuum of mono- and di-alkylpiperidines and there was evidence that several dimeric piperideines were formed. The low yields were discussed in …

A Comparison Of Recruitment Strategies Among Brachyuran Crustacean Megalopae Of The York River, Lower Chesapeake Bay And Adjacent Shelf Waters, David Franklin Johnson

OES Theses and Dissertations

Twenty-one stations forming a transect of the Pamunkey River, York River, lower Chesapeake Bay and adjacent coastal waters were sampled from July through September 1980. The megalopa stages of 11 brachyuran species were sampled. Vertical and horizontal distributions are described for each species in relation to salinity and water column stratification. The megalopae are assigned to three apparent recruitment strategies: retained estuarine, expelled estuarine and retained coastal megalopae. the megalopa stages of estuarine adults, such as Hexapanopeus angustifrons, Neopanope sayi, Panopeus herbstii and Pinnotheres ostreum, are retained in estuarine epibenthic waters, while Rhithropanopeus harrisii are retained in slightly shallower …

The Temporal And Spatial Distribution Of Hydrocarbons In Atmospheric Deposition From Stations Surrounding Lower Chesapeake Bay, David Benjamin Webber

OES Theses and Dissertations

Hydrocarbon concentrations were determined in bulk, wet, and dry deposition samples from urban and non-urban locations surrounding lower Chesapeake Bay. Mean hydrocarbon concentrations in bulk deposition samples were over three times greater at the urban station indicating a localized source. The major hydrocarbons present were n-alkanes, polycyclic aromatic hydrocarbons (PAH), and the unresolved complex mixture (UCM). The PAH and the UCM were an indication of significant anthropogenic inputs while the odd/even distribution of the n-alkanes was an indication of biogenic sources. These findings indicated seasonal trends of highest biogenic hydrocarbon inputs in the spring and summer months and highest anthropogenic …

A Capacitance Wavestaff And Measurements Of Wave Height Decay In The Surf Zone, David L. Timpy

OES Theses and Dissertations

A wavestaff system utilizing capacitance was developed to measure wave heights in the surf zone. Data were used to test the assumption that wave height decays linearly across the surf zone. The instrument system consisted of two wavestaffs and housing which contained the needed electronic circuits and a data recorder. Acceptable frequency response for waves of period greater than two seconds could not be obtained if sensor wires were greater than 0.35 mm in diameter. The size used was 0.35 mm.

Local Lp-Saturation Of Positive Linear Convolution Operators, J. J. Swetits, B. Wood

Mathematics & Statistics Faculty Publications

Local L_p-saturation of positive linear convolution operators is investigated. Results are obtained for two important classes of operators previously studied by Bojanic, DeVore, Korovkin and the authors.

An Evaluation Of Nutrient Sources To Onslow Bay, North Carolina, Larry P. Atkinson, Leonard J. Pietrafesa, Eileen E. Hofmann

CCPO Publications

Hydrographic and current meter data from Onslow Bay, North Carolina, were examined to determine the relative importance of various nutrient sources.

Upwelled Gulf Stream water is the major source of nutrients while rivers represent a minor, if not insignificant, source. In the summer during stratified conditions, the upwelled water penetrates across the shelf, but in the winter the upwelled water is restricted to the outer shelf. Nitrate flux across the 40 m isobath was calculated from continuous temperature and current records. Flux during the summer of 1976 was 2 μM m² sec^-1 which is considerably less than flux …

Organic N-Chloramines: Chemistry And Toxicology, Frank E. Scully, Jr., Maxwell A. Bempong

Chemistry & Biochemistry Faculty Publications

The stability of aqueous solutions of organic N-chloramines, suspected of contaminating chlorinated water, has been studied. Two factors influence the decomposition of solutions of N-chloropiperidine and N-chlorodiethylamine: a spontaneous decomposition and photodecomposition. Since solutions of these compounds are relatively long-lived, a need for an analytical method for their identification is discussed. A new method is described which involves reaction of organic N-chloramines with arenesulfinic acid salts. The method gives high yields of stable arenesulfonamides. Several toxicological studies of N-chloropiperidine are described. The compound is mutagenic by Ames assay in Salmonella typhimurium strain TA 100 and does not require metabolic activation …

Unbounded Functions And Positive Linear-Operators, J. J. Swetits, B. Wood

Mathematics & Statistics Faculty Publications

The approximation of unbounded functions by positive linear operators under multiplier enlargement is investigated. It is shown that a very wide class of positive linear operators can be used to approximate functions with arbitrary growth on the real line. Estimates are given in terms of the usual quantities which appear in the Shisha-Mond theorem. Examples are provided.

Picosecond Laser Pulse Irradiation Of Crystalline Silicon, K. L. Merkle, H. Baumgart, R.H. Uebbing, F. Phillipp

Electrical & Computer Engineering Faculty Publications

Morphology changes introduced by picosecond laser pulses at λ = 532 nm and 355 nm in (111) and (100) silicon samples are studied by means of optical and high-voltage electron microscopy. Depending on energy fluence, orientation and wavelength, amorphous or highly defective regions may be created. From an analysis of damage thresholds and damage depth distributions it is concluded that melting and energy confinement precedes the formation of the structural changes.

Smallest Cubic And Quartic Graphs With A Given Number Of Cutpoints And Bridges, Gary Chartrand, Farrokh Saba, John K. Cooper Jr., Frank Harary, Curtiss E. Wall

Mathematics & Statistics Faculty Publications

For positive integers b and c, with c even, satisfying the inequalities b+1≤c≤2b, the minimum order of a connected cubic graph with b bridges and c cutpoints is computed. Furthermore, the structure of all such smallest cubic graphs is determined. For each positive integer c, the minimum order of a quartic graph with c cutpoints is calculated. Moreover, the structure and number of all such smallest quartic graphs are determined.