Physical Sciences and Mathematics Commons^™

Osmotic Tolerance And Volume Regulation In Cultured Cells Of The Oyster Pathogen Perkinsus Marinus, Caroline L. O'Farrell

Dissertations, Theses, and Masters Projects

No abstract provided.

Constrained Least-Squares Digital Image Restoration, Rajeeb Hazra

Dissertations, Theses, and Masters Projects

The design of a digital image restoration filter must address four concerns: the completeness of the underlying imaging system model, the validity of the restoration metric used to derive the filter, the computational efficiency of the algorithm for computing the filter values and the ability to apply the filter in the spatial domain. Consistent with these four concerns, this dissertation presents a constrained least-squares (CLS) restoration filter for digital image restoration. The CLS restoration filter is based on a comprehensive, continuous-input/discrete- processing/continuous-output (c/d/c) imaging system model that accounts for acquisition blur, spatial sampling, additive noise and imperfect image reconstruction. The …

The Characterization Of The Radiative Energy Transfer Process Among Holmium(3+) Ions In Yttrium(3) Aluminum(5) Oxygen(12), Terri Lynn Lazarus

Dissertations, Theses, and Masters Projects

This research comprises a comprehensive spectroscopic study of the characteristics of the solid state crystal YAG (Yttrium Aluminum Garnet) singly doped with Ho (Holmium) ions. An important area of solid state laser crystal research is the determination and optimization of the processes within these laser crystals which lead to efficient laser action. In most laser crystals, there is a donor ion such as Tm (Thulium) and an acceptor ion such as Ho. The donor ion generally has greater absorption than that of the acceptor at the wavelength of the pump source. The donor ion can transfer this absorbed energy to …

Mechanisms Of Poly(Vinyl Chloride) Fire Retardance And Smoke Suppression Induced By Copper Additives, Jong Paul Jeng

Dissertations, Theses, and Masters Projects

The purpose of this study was to elucidate the mechanisms of PVC fire retardance and smoke suppression induced by copper additives.;The experimental approaches involved: (1) the use of activated copper (Cu{dollar}\sp0{dollar}) to study PVC model-compound reactions and the crosslinking of PVC and (2) the pyrolysis of PVC model compounds in the presence of several copper additives in order to examine all of the possible chemical reactions involved in the formation of heavy products.;The results obtained from experiments with activated copper and allylic chloride model compounds suggest that the reductive coupling mechanism is a viable process in PVC. The Cu{dollar}\sp0{dollar} that …

Beam Dynamics In The Cebaf Superconducting Cavities, Zenghai Li

Dissertations, Theses, and Masters Projects

This work is a study of beam dynamics in the CEBAF superconducting cavities under the influence of the fields generated by externally applied RF and beam particles.;A full 3-D modeling of the CEBAF 5-cell superconducting cavity is carried out. Details of the modeling with MAFIA are discussed. Multipole fields due to the asymmetric couplers are studied by means of 3-D Fourier transforms. The cavity steering and focusing of the multipole fields are studied. Experimental measurements of these effects are performed to validate the modeling. Evaluation of the cavity misalignment is discussed. The emittance degradation effects in the CEBAF superconducting linacs …

Search For Metastability Of 2s Muonic Neon, Bernard Wilhelm Bach

Dissertations, Theses, and Masters Projects

An experiment was performed at the Paul Scherrer Institut (PSI) to establish the conditions for the metastability of the 2S-state of muonic neon. The muonic atoms were formed by stopping negative muons in the neon-filled target chamber of the PSI cyclotron trap. A pair of intrinsic germanium detectors were used in coincidence to search for the two photon decay of the 2S-state. Both energy and time information from two photon events were written to disk for off-line analysis. Data were accumulated for neon pressures of 40 and 400 Torr. The data were then searched for evidence of two photon transitions …

Calculations Of The Interactions Of Energetic Ions With Materials For Protection Of Computer Memory And Biological Systems, Myung-Hee Y. Kim

Dissertations, Theses, and Masters Projects

Theoretical calculations were performed for the propagation and interactions of particles having high atomic numbers and energy through diverse shield materials including polymeric materials and epoxy-bound lunar regolith by using transport codes for laboratory ion beams and the cosmic ray spectrum. Heavy ions fragment and lose energy upon interactions with shielding materials of specified elemental composition, density, and thickness. A fragmenting heavy iron ion produces hundreds of isotopes during nuclear reactions, which are treated in the solution of the transport problem used here. A reduced set of 80 isotopes is sufficient to represent the charge distribution, but a minimum of …

Occurrence, Fate And Effects Of Polychlorinated Terphenyls In An Estuarine Environment, Kathryn Gallagher

Dissertations, Theses, and Masters Projects

Aroclor 5432, a mixture of polychlorinated terphenyls (PCT), was detected in sediment and several biological compartments including: saltmarsh cordgrass (Spartina alterniflora), American oysters (Crassostrea virginica), red-jointed fiddler crabs (Uca minax), wharf crabs (Sesarma reticulatum) and mummichogs (Fundulus heteroclitus) collected from Tabbs Creek. This tidal creek is located in the southern Chesapeake Bay region. Species from several phyla were selected in order to examine PCT accumulation in physiologically and ecologically different organisms. In general, PCT concentrations in sediment and biota decreased with distance downstream from the PCT outfall. The organism with the highest mean concentration (18,300 &\mu&g/kg dry weight) was the …

Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen

Dissertations, Theses, and Masters Projects

Chloroguaiacols are common components of bleached kraft pulp mill effluent known to bioaccumulate in aquatic organisms, and sorb onto particulate material and sediments. Ionization properties of the chloroguaiacols must be known in order to explain their sorptive behavior in aquatic systems. to obtain this information, thermodynamic acid dissociation constants (p&K\sb{lcub}\rm a{rcub})& of guaiacol (o-methoxyphenol) and nine chloroguaiacols have been determined by spectrophotometric methods. These experimental p&K\sb{lcub}\rm a{rcub}& values have been compared with literature values, values predicted by the Hammett equation and predictions by quantum chemical calculations using MOPAC 6.0 with AM1 and MNDO Hamiltonian operators. Experimental and predicted acidities were …

Resuspension Behavior Of Natural Estuarine Sediments, Chang-Hee Lee

Dissertations, Theses, and Masters Projects

The resuspension behavior of natural estuarine sediments was studied using the VIMS Sea Carousel, a benthic annular flume. The bed shear stresses produced by the flume were measured by a hot-film sensor mounted flush on the bottom of a laboratory version of the Carousel under a clear-water and flat-bottom condition. Measurements showed a reasonably uniform bed shear stress across the channel and agreed with the relationship &\tau\sb{lcub}\rm b{rcub}=0.011\Omega\sp{lcub}1.69{rcub},& where &\Omega& = ring speed (rpm) and &\tau\sb{lcub}\rm b{rcub}& = spatially-averaged bed shear stress (N/m&\sp2&), predicted from a previous numerical study. Thus, the &\tau\sb{lcub}\rm b{rcub}& was used as a bed shear stress …

Studies On Processes Controlling The Input Of Agricultural Chemicals In Groundwater To Surface Waters, Edward Laurence Libelo

Dissertations, Theses, and Masters Projects

This dissertation describes several studies of groundwater quality, the fate and transport of nutrients and atrazine in groundwater systems and physical processes at the sediment-water interface which impact on groundwater discharge. Groundwater monitoring wells were installed at the Goodwins Island and Catlett Island NERRS sites in Virginia and agricultural, suburban and forest land use sites in the York and James River Basins. Groundwater was analyzed for nutrients, pH, salinity and trace organics. Shoreline land use, associated nutrient loading and an estimate of total groundwater flux suggest that groundwater contributes up to 30% of the total nitrogen input to the Chesapeake …

Patentability Of Computer Inventions, Robert C. F. Perez

Dissertations, Theses, and Masters Projects

No abstract provided.

The Selective Synthesis Of 3-Alkylidenetetrahydrofurans, Robin Elaine Southward

Dissertations, Theses, and Masters Projects

No abstract provided.

The Synthesis Of Benzophenane 3,5-Dicarboxylic Acid For The Double Capping Of Beta-Cyclodextrin, Jaydee Dones Cabral

Dissertations, Theses, and Masters Projects

No abstract provided.

Metallization Of Polyimide Films To Enhance Dimensional Stability And To Achieve Reflective And Conductive Surfaces, David Scott Thompson

Dissertations, Theses, and Masters Projects

No abstract provided.

Characterization Of Nylon-11 Degradation, Leslie Christian Mccullough

Dissertations, Theses, and Masters Projects

No abstract provided.

Characterization Of Pr500 For Use In Resin Transfer Molding, Rhonda Michelle Barksdale

Dissertations, Theses, and Masters Projects

No abstract provided.

Blends Of Reactive Diluents With Phenylethynyl-Terminated Arylene Ether Oligomers, Rachel Louise Knudsen

Dissertations, Theses, and Masters Projects

No abstract provided.

Immigration Variability And Post-Settlement Processes Of The Spiny Lobster, Panulirus Argus, In The Exuma Cays, Bahamas, Luis Coba-Cetina

Dissertations, Theses, and Masters Projects

No abstract provided.

Ocean Biogeochemical Fluxes - New Production And Export Of Organic-Matter From The Upper Ocean, Hw Ducklow

VIMS Articles

Studies of ocean biogeochemical fluxes have been energized in this decade, by the urgency of our need to understand and predict the effects of continued CO₂accumulation in the atmosphere, by the global perspectives offered by satellite views of ocean color and related physical fields (McClain et al. 1991; Yoder et al. 1992; Mitchell 1994), and by the successful implementation of the Joint Global Ocean Flux Study (JGOFS; Bowles and Livingston, 1993). In this review, I focus on oceanic new production, originally defined as the fraction of primary production supported by inputs of ‘new’ nitrogen from outside the euphotic …

Calcium Carbonate Sedimentation In The Global Ocean: Linkages Between The Neritic And Pelagic Environments, John D. Milliman, Andre W. Droxler

VIMS Articles

Other than fluvial sediment, calcium carbonate (CaCO3) is the greatest source of sediment in the present-day ocean. Interest in carbonate sedimentation extends beyond geologists because the carbonate system involves biologic and geochemical
processes. Carbonate production, for example, releases CO2 but its accumulation becomes a major sink for inorganic carbon.

Unlike fluvial sediments, modern carbonates accumulate more or less equally in the neritic and pelagic environments. Neritic carbonates (benthic) are characterized by rapid production of (mostly) metastable aragonite and magnesian calcite:pelagic production of (primarily) calcite in the open ocean occurs at much slower rates but overmuch larger areas than does neritic …

Resuspension Behavior In The Lower Chesapeake Bay, J.P. -Y Maa, C. -H. Lee

VIMS Books and Book Chapters

Using the VIMS Sea Carousel to conduct in-situ experiments in lower Chesapeake Bay, we found significant spatial a.nd temporal difference of the critical bed shear stress for sediment resuspension, tcr- At the Wolftrap site, tcr varied from 1.1 Pa in the summer to 1.9 Pa in the winter. At the Burwell Bay site, although the bed was too soft for anchoring our research vessel against the changing tide, we identified that tcr was 0.045 Pa. At the Old Plantation site, there was a small amount of fluffy material on top of the bed. At a winter deployment at the Cherrystone …

A Three-Dimensional Hydrodynamic-Eutrophication Model (Hem-3d) : Description Of Water Quality And Sediment Process Submodels, Kyeong Park, Albert Y. Kuo, Jian Shen, John M. Hamrick

Reports

Virginia Institute of Marine Science (VIMS) has been developing a general purpose three-dimensional hydrodynamic and sediment transport model, Environmental Fluid Dynamics Computer Code (EFDC; Hamrick 1992). The real-time model simulates density and topographically-induced circulation as well as tidal and wind-driven flows, and spatial and temporal distributions of salinity, temperature and sediment concentration. The model also is capable of handling the wetting and drying of shallow area, hydraulic control structures, vegetation resistance for wetlands and Lagrangian particle tracking. The information of physical transport processes, both advective and diffusive, simulated by the hydrodynamic model can be used to account for the transport …

A Delta-F Monte Carlo Method To Calculate Parameters In Plasmas, Maciek Sasinowski

Dissertations, Theses, and Masters Projects

A Monte Carlo code has been developed which very efficiently calculates plasma parameters, such as currents, potentials and transport coefficients for a fully three dimensional magnetic field configuration. The code computes the deviation, f, of the exact distribution function, f, from the Maxwellian, {dollar}F\sb{lcub}M{rcub},{dollar} with {dollar}\psi{dollar} the toroidal magnetic flux enclosed by a pressure surface and H the Hamiltonian. The particles in the simulation are followed with a traditional Monte Carlo scheme consisting of an orbit step in which new values for the positions and momenta are obtained and a collision step in which a Monte Carlo equivalent of the …

Evidence For A Relation Between A White Perch Young-Of-The-Year Index And Indices Of Later Life Stages, Thomas C. Mosca Iii, Herbert M. Austin, David M. Plotner

VIMS Books and Book Chapters

Juvenile indices are employed in fisheries management to predict the future abundance of harvestable adults. Frequently, regulations on the utilization of the resource, and a lack of fishery independent abundance data, make verification of the prediction accuracy impossible. In the case of white perch in Virginia, this is not so. Using the weighting system developed for a Chesapeake Bay-wide index of juvenile striped bass abundance based on summertime beach seine data collected in nursery ground waters, we developed a similar index for white perch in the Virginia portion of the Bay. Regressions against Virginia Institute of Marine Science otter trawl …

The Precarious State Of The Chesapeake Public Oyster Resource, William J. Hargis Jr., Dexter S. Haven

VIMS Books and Book Chapters

The 243,000 acres of Virginia's public oyster reefs (a.k.a. the Baylor Grounds) have been extremely productive of usable and saleable (market .md seed) oysters (Crassostrea virginica), oyster shells and oyster shell by-products. Archaeological remains and historical records show that they have yielded great numbers of whole oysters, oyster meats, oyster "seed" and shell since the 01esapeake was formed some 3,000 years BP. In the last century their natural productivity, as indicated by commercial harvest records (the only long-term data available), has declined markedly. In 1904, Vrrginia's total market (adult) oyster harvest was about 7.6 million bushels (mostly from public grounds). …

Critical Elements In The Application Of Water Quality Standards To Wetlands : Classification System, Beneficial Use Designation And The Identification Of Exceptional Wetlands, Pamela A. Mason, Carl H. Hershner, Virginia Institute Of Marine Science. Department Of Resource Management And Policy, Wetlands Program

Reports

No abstract provided.

Regulating The Blue Crab, Callinectes Sapidus, Fishery In Virginia : Biological And Economic Concerns, James E. Kirkley, William D. Dupaul, Michael J. Oesterling

Reports

The blue crab, Callinectes sapiclus, fishery has been one of the most important fisheries of Virginia. The importance of the fishery in terms of commercial activities has substantially increased in recent years in response to declining resource levels of American Oyster, Crassostrea virginica, and a growing international and domestic demand for soft crabs, female hard crabs, and crab meat.

The actual economic importance of the fishery, however, is not well known. For example, what are the employment and earning levels generated by the fishery? What portion of a waterman's household income is derived from crabbing? How much does crabbing contribute …

Water Resources : Planning For Future Demand In The York River Basin, Mel Vargas, Carl Hershner, Marcia Berman

Reports

This report analyzes issues related to water supply and demand for the York River Basin (YRB) in Virginia.

Stafford County Shoreline Protection Report, Potomac River, Aquia Creek : Prepared For County Of Stafford, Department Of Planning And Community Development, Vhb : Vanasse, Hangen And Brustlin, Inc., Virginia Institute Of Marine Science

Reports

No abstract provided.