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Articles 5701 - 5730 of 5947
Full-Text Articles in Physical Sciences and Mathematics
The Effects Of X-Irradiation On The Metamorphosis And Budding Of Aurelia Aurita, Michael John Prokopchak
The Effects Of X-Irradiation On The Metamorphosis And Budding Of Aurelia Aurita, Michael John Prokopchak
OES Theses and Dissertations
With the aid of the Aurelia Metamorphosis Test System, the acute or subtle morphological and behavioral effects of irradiation on the Norfolk Aurelia aurita were described and the sensitivity to X-irradiation of those organisms receiving thyroxine and those not receiving thyroxine was compared. Levels of radiation were 0 (control), 5,000, 10,000, 15,000, 20,000 and 40,000 rads. Morphology of the ephyrae, statolith and rhopalia numbers were recorded using the light microscope, Developmental abnormalities of the scyphistomae and ephyrae were recorded with the scanning electron microscope and light microscope. Two major findings from this investigation were the absence of rhopalia and statoliths …
Numerical Experiments With The Quasigeostrophic Potential-Vorticity Equation, Peter L. Spence
Numerical Experiments With The Quasigeostrophic Potential-Vorticity Equation, Peter L. Spence
OES Theses and Dissertations
A method is developed to model the circulation of a barotropic, 8-plane ocean under an imposed steady wind stress. The model includes the effect of both horizontal and vertical friction along with nonlinear advection of vorticity. Implementing the method involves solving the unsteady quasigeostrophic potential-vorticity equation using a compact finite difference scheme (Gatski, Grosch, and Rose, 1982).
Once developed, this model is used in four separate numerical experiments. In each experiment, a model ocean with an initial flow field is driven to a steady state solution. Vertical viscosity is held constant in the first three experiments while lateral viscosity is …
Tectonic Implications Of Late Tertiary Strata Exposed Along The Piankatank River, Eastern Virginia, Daniel Stephen Lane
Tectonic Implications Of Late Tertiary Strata Exposed Along The Piankatank River, Eastern Virginia, Daniel Stephen Lane
OES Theses and Dissertations
Biostratigraphic analysis of Late Miocene and Pliocene strata along the Piankatank River in eastern Virginia exposes a juxtaposition of the Eastover and Yorktown Formations. This structure is situated on a NE trending alignment of geological, geomorphic, and geophysical features which run from southern Virginia to northern Delaware. Tectonic jointing in isolated sandstone bodies and fracture controlled drainage patterns provide further evidence of post-middle Pliocene tectonism in the region. The lateral spacing of this structure from the Stafford and Brandywine fault zones and other linear features on the Coastal Plain strongly implies that a structural similarity exists between the Piankatank structure …
Stratigraphy And Textural Analyses Of A Beach Ridge Complex, Cape Henry, Virginia, Daniel Leland Oyler
Stratigraphy And Textural Analyses Of A Beach Ridge Complex, Cape Henry, Virginia, Daniel Leland Oyler
OES Theses and Dissertations
Eight lithological units, documented from the analyses of 26 boreholes, comprise five laterally extensive horizons in the subsurface of Cape Henry, Virginia. Interpretations of the environments of deposition for those units are based upon textural and compositional features, fossils, thickness and distribution of strata, and previous reports about late Tertiary and Quaternary deposits in nearby areas. The incised, Pliocene Chowan River Formation (Unit H) underlies Pleistocene Units F and G which are concentrated in a buried river valley beneath Cape Henry. Estuarine Units D and E resulted from a marine transgression of the study area during the early Holocene. The …
Characterization Of Trihalomethane Formation From Proteins In Chlorinated Water, Robert Aaron Kravitz
Characterization Of Trihalomethane Formation From Proteins In Chlorinated Water, Robert Aaron Kravitz
Chemistry & Biochemistry Theses & Dissertations
Traditionally humates have been considered the most significant precursor in the formation of trihalomethanes in finished drinking water. This study investigates another potential precursor, namely proteins. The chlorination of aqueous protein solutions yields significant levels of trihalomethanes in terms of the maximum contaminant level (MCL) of 0.100 mg/L imposed by the USEPA. Molar yields for several proteins were determined. The average yield per unit of organic carbon was 0.5% as compared to 0.8% for a humic acid studied. A model protein, bovine serum albumin, was studied extensively to ascertain the effects of total organic carbon, chlorine dose, and time on …
The Spatial And Temporal Distribution Of The Larvae Of Sympatric Pagurid Hermit Crabs (Decapoda, Anomura) In Virginian Estaurine And Coastal Waters, Philip Wesley Sadler
The Spatial And Temporal Distribution Of The Larvae Of Sympatric Pagurid Hermit Crabs (Decapoda, Anomura) In Virginian Estaurine And Coastal Waters, Philip Wesley Sadler
OES Theses and Dissertations
Thirteen stations were occupied at two - week intervals from May through September 1980 within the York River, lower Chesapeake Bay depths encompassing the entire water column.
Three species of pagurids were identified: Pagurus longicarpus, P. pollicaris, and P. annulipes. The larvae of P. annulipes had not been previously identified from Virginian waters. The shapes of the antennae of P. pollicaris and P. annulipes weredistinctive, allowing rapid identification of these larvae. The shapes of the uropods were found to be useful in distinguishingthe glaucothoe· of P. longicarpus from P. annulipes. The larvae of these species …
Determination Of The Internal Rotational Energy Of Gaseous 1,2-Dichloroethane In An Argon Matrix Using Fourier Transform Spectroscopy, Susan Lynn Clarke
Determination Of The Internal Rotational Energy Of Gaseous 1,2-Dichloroethane In An Argon Matrix Using Fourier Transform Spectroscopy, Susan Lynn Clarke
Chemistry & Biochemistry Theses & Dissertations
A sample cell and delivery system for rapid matrix isolation of gas mixtures at constant gas temperature was designed and evaluated. The rotational energy differences of 1,2-dichlorosthane and of its deuterium compound wars then determined to test this technique.
The rotational energy barriers calculated from Boltzman plots of ths gases at different temperatures were; 1.21 + 0.38 keel/mole, 1.33 + 0.70 Real/mole, and 1.12 + 0.45 kcal/mole for the CH2 wagging„ C-Cl stretching and CD2 wagging modes respectively. These values were in good agreement with previously published values.
These results allowed evaluation of this apparatus and experimental design and …
Fourier Series Analysis Of The Relationship Of Morphologic Variations And Bathymetry In Recent Bolivina (Foraminiferida) From The Northwestern Gulf Of Mexico, Anthony Cavedo Gary
Fourier Series Analysis Of The Relationship Of Morphologic Variations And Bathymetry In Recent Bolivina (Foraminiferida) From The Northwestern Gulf Of Mexico, Anthony Cavedo Gary
OES Theses and Dissertations
Automated video digitization and closed-form Fourier series analysis were used to investigate the applicability of benthic foraminiferal test morphology for paleo-bathymetric/paleoenvironmental reconstructions. Sample relationships and harmonics with the greatest power for discriminating between samples were determined using canonical discriminant analysis. Samples were eleven short cores obtained from the northwestern Gulf of Mexico. Three species of Bolivina were analyzed, B. albatrossi, B. lowmani, and B. subspinescens.
Results show populations of Bolivina albatrossi from the upper bathyal and upper-middle bathyal zones to have more triangular tests and lobulate chambers than lower-middle and lower bathyal zone populations. Specimens of Bolivina subspinescens …
Estimating The Parameters Of Truncated Distributions, Mukul Mohan Mittal
Estimating The Parameters Of Truncated Distributions, Mukul Mohan Mittal
Mathematics & Statistics Theses & Dissertations
The problem considered here is the estimation of the parameters of some special truncated distributions. If the sample observations are restricted to the interval {O, T} with T known, then it is well known in the literature that the method of maximum likelihood fails to provide a finite estimate, for the mean of an exponential distribution, whenever the sample mean is greater than T/2 (Deemer and Votaw, 1955, Ann. Math. Statist. 26, 498-504). Not so well known is the nonexistence of the maximum likelihood estimator (m.l.e.), under certain conditions, for the scale parameter of a gamma distribution from a truncated …
Triple Trigonometric Series And Their Application To Mixed Boundary Value Problems, Gordon Melrose
Triple Trigonometric Series And Their Application To Mixed Boundary Value Problems, Gordon Melrose
Mathematics & Statistics Theses & Dissertations
In this dissertation the author investigates some triple trigonometric series which occur in the solution of mixed boundary value problems in elasticity and potential theory. By choosing a suitable integral representation for the sequence of unknown constants, the problem is reduced to solving a singular integral equation of the first kind. Twenty four cases in which the integral equation can be solved in closed form are discussed in detail.
In later chapters, the application of triple trigonometric series to problems in physics and engineering is demonstrated and closed form solutions for the physical parameters of interest are obtained.
Block Encoding Of Speech Spectral Principal Components, James R. Holland Jr.
Block Encoding Of Speech Spectral Principal Components, James R. Holland Jr.
Electrical & Computer Engineering Theses & Dissertations
A Karhunen-Loeve series expansion was used to block encode speech spectral principal components as a function of time. Each of ten principal components was first obtained as a linear combination of 2© speech spectral band energies. Using a fixed block length of 10 frames (0.128 s), the K-L basis vectors were computed separately for various speakers for each principal component. In all cases the resulting basis vectors were essentially a set of discrete cosine basis vectors. Synthesis of speech from the block encoded parameters showed that very little information is lost with up to 70% data reduction. The block encoding …
Suboptimal Algorithms For Improvement Of Pipeline Through Insertion Of Delays, Sukhamoy Som
Suboptimal Algorithms For Improvement Of Pipeline Through Insertion Of Delays, Sukhamoy Som
Electrical & Computer Engineering Theses & Dissertations
Pipelining is now widely used in the design of high speed processors in order to overcome the intrinsic speed limitations imposed by the technology. For a good performance and avoidance of internal conflicts, the concurrent operations within different subunits of a pipeline architecture should be properly scheduled This scheduling problem is known to be intrinsically difficult" and a member of the "NP complete class of problems. The aim of this thesis is to develop heuristic suboptimal algorithms whose execution time is a polynomial function of the number of items to be scheduled. Insertion of delay is used as a basic …
Determinants For The Timing Of Escapement From The Sockeye Salmon Fishery Of The Copper River, Alaska: A Simulation Model, Howard A. Schaller
Determinants For The Timing Of Escapement From The Sockeye Salmon Fishery Of The Copper River, Alaska: A Simulation Model, Howard A. Schaller
OES Theses and Dissertations
A model to estimate determinants for migratory timing of catch and escapement in a terminal salmon fishery is presented. A method was developed to estimate average seasonal migration rates of salmon through a harvest area from catch and escapement data. The time series for the total population of Copper River sockeye salmon (Oncorhynchus nerka) was reconstructed in the reference frame of the commercial harvest area from catch and escapement data.
The catchability coefficients (q), derived from the reconstructed populations were found to vary within season and between seasons. The relation between q and effort was attributed to a …
Timing Of The Blue Crab Fisheries Of Virginia And Its Application To Harvest Management, J. Dale Shively
Timing Of The Blue Crab Fisheries Of Virginia And Its Application To Harvest Management, J. Dale Shively
OES Theses and Dissertations
The timing of a fishery is a quantitative expression of the composite behaviors of harvesters, markets, animals and climatic events. A quantitative description of the timing of the blue crab (Callinectes sapidus) fisheries of Virginia was established using the time density model of Mundy (1979). Blue crab catch statistics supplied by the National Marine Fisheries Service and the Virginia Marine Resource Commission were divided into two fisheries based on gear type; the summer and winter fisheries. Average performance curves were then constructed using average cumulative proportions of catch. Annual yield estimates were also made and timing in five …
An Intraseason Forecasting System For Commercial Marine Fisheries, Erik J. Barth
An Intraseason Forecasting System For Commercial Marine Fisheries, Erik J. Barth
OES Theses and Dissertations
The reliability of an intraseason yield estimation technique which is commonly used by Pacific salmon harvest managers is evaluated for applicability to a variety of commercial finfish and crustacean fisheries. The estimation technique is known as the average timing or the average performance model. The method is not easily related to standard statistical models, but does show some similarity to both a single parameter linear regression model and the ratio estimator of sampling theory. A comparison of these models, a two parameter linear model, and a regression estimator is made to determine if the precision of forecasts of performance can …
An Investigation Of Refractive Index Of Solutions Of Ammonia And Water At Various Concentrations And Temperatures, Effendy Arif
An Investigation Of Refractive Index Of Solutions Of Ammonia And Water At Various Concentrations And Temperatures, Effendy Arif
Mechanical & Aerospace Engineering Theses & Dissertations
Refractive index of ammonia-water solutions is investigated experimentally (for (lamda) = 632.8 nm) and semi-empirically (for (lamda) = 589.3 and 632.8 nm) in ammonia-weight concentration of up to 30%, over a temperature range of 20 to 60(DEGREES)C. The experiment employs a specially designed and built refractometer that measures the displacement of a laser beam due to refraction in the test solution. The refractive index is then deduced from the beam displacement. Based on the experimental data, the refractive index is correlated empirically with the concentration and temperature. A semi-empirical investigation is developed based on the Lorentz-Lorenz equation and the additive …
An Examination Of The Variability Of Migratory Timing Statistics Estimated From Catch And Effort Observations, Arthur J. Butt
An Examination Of The Variability Of Migratory Timing Statistics Estimated From Catch And Effort Observations, Arthur J. Butt
OES Theses and Dissertations
The estimate of the mean arrival time based on catch or CPUE of fishes migrating into a fixed harvest area is a function of the number of days fished. Simulation studies using chinook salmon catch and effort data from the Yukon River delta, Alaska indicate that fishing effort concentrated at the tails of the migratory distribution which would tend to erroneously weigh the estimated mean arrival time in the direction of the sample, away from the true mean, is only a significant problem when the number of days open to fishing is small, covering less than 12% of the total …
Investigation Of Matrix Effects On The Furnace Atomic Absorption Signals Of Chromium, Nickel And Selenium, Susan Marie Viet
Investigation Of Matrix Effects On The Furnace Atomic Absorption Signals Of Chromium, Nickel And Selenium, Susan Marie Viet
Chemistry & Biochemistry Theses & Dissertations
The flameless atomic absorption signals of chromium, nickel and selenium are subject to matrix interferences arising from inorganic salts and anions commonly found in urine. The effects of such salts on the atomic absorption signals were investigated using Polarized Zeeman Effect background correction in conjunction with a detector/readout system capable of resolving absorbance signals in 18 msec readings. Both optical temperature control and current temperature control were employed for each analysis. Peak area, peak height, peak shape and appearance time were compared for matrix-free standards and matrix-containing standards.
The influence of the inorganic salts on the metal analyses was found …
A Method For Determining Creosote Contamination Of Sediment From The Elizabeth River, Norfolk, Va, Elizabeth G. Merrill
A Method For Determining Creosote Contamination Of Sediment From The Elizabeth River, Norfolk, Va, Elizabeth G. Merrill
OES Theses and Dissertations
Hydrocarbon input sources to the Elizabeth River were investigated. Carbonized coal products (creosote, coal tar, and roof tar), petroleum products (Kuwait Crude Oil, No. 2 Fuel Oil, and a fuel oil spill sample) and soot (woodstove and diesel engine) have unique hydrocarbon distributions. Elizabeth River sediment hydrocarbon distributions indicate that they are contaminated with both carbonized coal and petroleum products. Using a simple two member mixing model, greater than 65 percent of Elizabeth River sediments' resolved aromatic compounds were determined to originate from carbonized coal products. These aromatic hydrocarbons include the EPA priority pollutant polynuclear aromatic hydrocarbons which are known …
A Description And Analysis Of The Timing Of Virginia's Weakfish Fishery, Bruce William Hill
A Description And Analysis Of The Timing Of Virginia's Weakfish Fishery, Bruce William Hill
OES Theses and Dissertations
The seasonality of Virginia's weakfish fishery is quantitatively defined by providing a mean time of catch and variance of catch for the years 1960 - 1981. On the average. the central half of the population is available for harvest from mid-May through September in all of Virginia's waters and the mean date of harvest is July 20th • The 22 year average variance of catch for Virginia's waters is 3.97. In Virginia's Chesapeake Bay tributaries the mean date of harvest is July 17th and the 22 year average variance of catch is 2.50. There is evidence for an inverse relationship …
A Theoretical Model For Calculation Of Molecular Stopping Power, Yuan-Jian Xu
A Theoretical Model For Calculation Of Molecular Stopping Power, Yuan-Jian Xu
Physics Theses & Dissertations
A modified local plasma model based on the work of Linhard-Winther, Bethe, Brown, and Walske is established. The Gordon-Kim's molecular charged density model is employed to obtain a formula to evaluate the stopping power of many useful molecular systems. The stopping power of H2 and He gas was calculated for incident proton energy ranging from 100 KeV to 2.5 MeV. The stopping power of O2, N2 and water vapor was also calculated for incident proton energy ranging from 40 keV to 2.5 MeV. Good agreement with experimental data was obtained.
A discussion of molecular effects leading …
The Aquatic Geochemistry Of The Particle-Reactive Radionuclides Po-210, Pb-210, And Be-7, James Forrest Todd
The Aquatic Geochemistry Of The Particle-Reactive Radionuclides Po-210, Pb-210, And Be-7, James Forrest Todd
OES Theses and Dissertations
Integrated monthly wet-only and bulk precipitation samples for Be-7 and Pb-210 analysis were collected from November 1982 through October 1983 at two sites in lower Chesapeake Bay. Atmospheric deposition fluxes for Be-7 in wet-only and bulk precipitation averaged 0.013 and 0.014 pCi/cm2/d, respectively, and for Pb-210 averaged 0.36 and 0.40 pCi/cm2/yr, respectively, suggesting that dry deposition makes only a minor contribution to the total fluxes.
A seasonal trend was observed in the depositional flux of Be-7, with a pronounced maximum in the Spring. Approximately 40 percent of the annual Be-7 deposition occurred between February and April, …
Analysis Of Central Equatorial Pacific Water Masses By Method Of Principal Components, Ross Tuxhorn
Analysis Of Central Equatorial Pacific Water Masses By Method Of Principal Components, Ross Tuxhorn
OES Theses and Dissertations
The distribution of Antarctic Intermediate Water at the extent of dispersion in the equatorial Pacific Ocean was investigated by means of multivariate analysis. Interrelationships among the upper intermediate water masses at this location are proposed.
Oceanographic data contained in seven cruise legs measured during the 1979-80 Hawaii to Tahiti Shuttle Experiment formed the basis of this study. Six parameters -- temperature, salinity, dissolved oxygen, phosphate, silicate and nitrate -- were used in the method of principal component analysis to classify water masses between the sea surface and 1000m. The derived water masses were compatible with previously described oceanographic features of …
Partial Radiative Recombination Cross Sections For Excited States Of Hydrogen, Patricia M. Fazio
Partial Radiative Recombination Cross Sections For Excited States Of Hydrogen, Patricia M. Fazio
Physics Theses & Dissertations
In calculating the radiative recombination cross sections for interstellar H II regions usually only the electric dipole term in the expansion of the interaction Hamiltonian is kept. However, conditions present in these regions permit recombination into highly excited states and the "effective size" of the atom is not much less than the wavelength of the emitted photon. These physical conditions do not meet the requirements for making the dipole approximation. A higher order approximation is to keep an additional term in the expansion of the Hamiltonian, and, therefore, to include contributions of quadrupole transitions in the calculation of the partial …
Phytoplankton Ecology And Dynamics In The James River Estuary Virginia, U. S. A., Margaret J. Filardo
Phytoplankton Ecology And Dynamics In The James River Estuary Virginia, U. S. A., Margaret J. Filardo
OES Theses and Dissertations
Autotrophic biomass and productivity as well as nutrient distributions and phytoplankton cell populations in the James River estuary, Virginia, from Newport News Shipyard to the 0 o/oo isohaline, were sampled on a monthly basis from August of 1981 to December of 1982. Particular emphasis was placed on the very low salinity region (defined as the location where surface salinity measured between 0.0 and 0.75 o/oo based on conductivity) in order to determine the fate of fresh water phytoplankters upon being advected into the estuary because of their suspected role in the biogeochemical cycling that occurs there.
Both chlorophyll a and …
Block Transform Coding Of Presample Filtered Data, Thomas A. Shull
Block Transform Coding Of Presample Filtered Data, Thomas A. Shull
Electrical & Computer Engineering Theses & Dissertations
This dissertation addresses the application of non-adaptive transform coding for bit rate reduction of presampled filtered data. Transform coding is examined as an alternative to conventional pulse code modulation (PCM) for multi-source, fixed rate data acquisition systems. Typical bandlimiting presample filters introduce redundancy into the sequence of data samples. Linear transformation of successive N-length blocks of the data sequence and subsequent binary coding of the resulting components is shown to lead to reduced average bit rate for the same less distortion as PCM.
Four Butterworth filters, two corresponding to eight bit PCM systems, and two corresponding to ten bit PCM …
A Plasma Focus Interrupting Switch, Gregory Francis Knapp
A Plasma Focus Interrupting Switch, Gregory Francis Knapp
Electrical & Computer Engineering Theses & Dissertations
The feasibility of using a dense plasma focus (DPF) as a current interrupting device has been investigated. Specifically, a 34-kJ, Mather-type DPF was modified to accept a third electrode so that a discharge could be created between this electrode and the center electrode of the DPF by a 10-kJ inductive energy storage circuit. It was anticipated that the accelerating mechanisms of the DPF pinch, which are known to cause a rapid reduction in the DPF current, would interrupt the 1-kA to 10-kA secondary discharge current thus forcing the secondary current through an external load and hence result in power amplification. …
Changes In The Lower Chesapeake Bay Food-Chain In Presence Of The Sea Nettle Chrysaora-Quinquecirrha (Scyphomedusa), David Feigenbaum, Michael Kelly
Changes In The Lower Chesapeake Bay Food-Chain In Presence Of The Sea Nettle Chrysaora-Quinquecirrha (Scyphomedusa), David Feigenbaum, Michael Kelly
OES Faculty Publications
The abundance of 4 levels of the lower Chesapeake Bay food chain (Chlorophyll a, herbivores, ctenophore Mnemiopsis leidyi, and Scyphomedusa Chrysaora quinquecirrha) were monitored twice weekly at 4 stations from May 10 through Sep 30, 1982 in the Lafayette and Elizabeth Rivers (Virginia). The herbivore standing stock, largely copepods, declined sharply in late May when M. Jeidyi appeared, but rebounded a month later when C. quinquecirrha medusae reduced the ctenophore population. Despite the additional presence of Aurelia aurita (Scyphomedusa) from Jul onward, herbivore abundance remained at moderate levels until the end of the study period. Phytoplankton abundance fluctuated …
Review Of Upwelling Off The Southeastern United States And Its Effect On Continental-Shelf Nutrient Concentrations And Primary Productivity, Larry P. Atkinson, James A. Yonder, Thomas N. Lee
Review Of Upwelling Off The Southeastern United States And Its Effect On Continental-Shelf Nutrient Concentrations And Primary Productivity, Larry P. Atkinson, James A. Yonder, Thomas N. Lee
CCPO Publications
Gulf Stream induced upwelling occurs along the length of the southeastern United States continental shelf break. Upwelling events are produced by northward propagating Gulf Streams frontal meanders and eddies and travel northwards with these features. Meanders and eddies occur throughout the year in a period band of 2-14 days; however, resultant upwellings can affect the shelf quite differently. During fall, winter, and spring, upwelling is restricted to the outer shelf by cross-shelf density distributions, but in the summer upwelled water may penetrate across as a subsurface intrusion if aided by upwelling-favorable winds. If water does penetrate across the shelf, it …
Coastal Upwelling Off The Rias Bajas, Galicia, Northwest Spain I: Hydrographic Studies, J. O. Blanton, L. P. Atkinson, F. Fernandez De Castillejo, A. Lavin Montero
Coastal Upwelling Off The Rias Bajas, Galicia, Northwest Spain I: Hydrographic Studies, J. O. Blanton, L. P. Atkinson, F. Fernandez De Castillejo, A. Lavin Montero
CCPO Publications
Coastal upwelling occurs off the Rias Bajas of Spain between April and October. Superimposed on large-scale upwelling is a mesoscale regime of enhanced upwelling induced by topographic influences. We show that the region surrounding Cape Finisterre has intensified topographically induced upwelling.
The rias have a relatively unobstructed connection with the open ocean. Upwelling of high nitrate water on the continental shelf by Ekman transport sets up pressure gradients at the mouth of the rias that induce upwelled water to flow into the rias. Deep water in the rias responds directly to cycles of upwelling and downwelling on the continental shelf.