Physical Sciences and Mathematics Commons^™

Trophic Effects Of Sponge Feeding Within Lake Baikal's Littoral Zone .2. Sponge Abundance, Diet, Feeding Efficiency, And Carbon Flux, Aj Pile, Mark R. Patterson, M. Savarese, V I. Chernykh, V A. Fialkov

VIMS Articles

Endemic freshwater demosponges in the littoral zone of Lake Baikal, Russia, dominate the benthic biomass, covering 44% of the benthos. We measured in situ sponge abundance and,orating and calculated sponge-mediated Fluxes of picoplankton (plankton <2 mu m) for two common species, Baikalospongia intermedia and Baikalospongia bacillifera. By means of dual-beam how cytometry, we found retention efficiencies ranging from 58 to 99% for four types of picoplankton: heterotrophic bacteria, Synechococcus-type cyanobacteria, autotrophic picoplankton with one chloroplast, and autotrophic picoplankton with two chloroplasts. By using a general model for organism-mediated fluxes, we conservatively estimate that through active suspension feeding, sponges are a sink for 1.97 g C d(-1) m(-1), mostly from procaryotic cell types. Furthermore, grazing by these extensive sponge communities can create a layer of picoplankton-depleted water overlying the benthic community in this unique lake.

Analysis Of Mercury Coordination Environments Of Tridentate And Tetradentate Nitrogen Based Ligands By Nmr Spectroscopy And X-Ray Crystallography, Rachel E. Freer

Dissertations, Theses, and Masters Projects

No abstract provided.

Polycyclic Aromatic Hydrocarbon (Pah) Distributions Within Urban Estuarine Sediments, Siddhartha Mitra

Dissertations, Theses, and Masters Projects

Sediments and pore waters from two urban estuaries ranging in sediment mixing energy were studied to evaluate the potential release of contaminants from particles during sediment diagenesis. Two sites in Elizabeth River, VA and two tributaries in the Hudson River Watershed were sampled for polycyclic aromatic hydrocarbons (PAHs). Sediment age, total sediment organic carbon (TOC), carbon to nitrogen (C/N) ratios, and particle surface area (SA) were also sampled at these sites. In the Elizabeth River, both sites sampled (Site 1 and Site 2) have been non-depositional for the past 70 y or are comprised of old dredge spoil. PAH K&\sp\prime\sb{lcub}\rm …

Semiclassical Picture Of Collision-Induced Λ-Doublet Transitions In Diatomic Molecules, Laurie J. Kovalenko, J. B. Delos

Arts & Sciences Articles

We investigate collision-induced Λ-doublet transitions in a system similar to NO+Ar, based on a semiclassical model in which nuclear motion is treated classically and electronic motion quantum mechanically. We present a picture of this process by monitoring〈Λ〉, the expectation value of the projection of electronic orbital-angular momentum onto the molecular NO axis, over the duration of the collision. In a typical collision, the interaction with Ar would cause the electronic orbital-angular momentum to precess about the rotating NO–Ar vector. However, since this angular momentum is locked tightly to the diatomic axis, it is restricted to oscillation along this axis. This …

Organic Carbon Abundance, Distribution And Metabolism At The Oyster, Virginia Study Site, Elizabeth Canuel, Iris C. Anderson, Craig Tobias

Reports

This report describes a pilot study conducted at the DOE Subsurface Science Program's study site in Oyster, VA. The objective of this study was to examine whether 2 organic matter associated with the solid and dissolved phases was labile enough to support microbial activity. Organic matter availability was assessed in two ways: (1) by quantifying the amount and distribution of total organic carbon (TOC) associated with the solid phase and (2) laboratory experiments to examine the utilization of dissolved organic matter by measuring total microbial respiration. In addition to assessing total respiration, we specifically addressed organic matter respiration via denitrification. …

Body Burden Of Polycyclic Aromatic Hydrocarbons And Tributyltin In Hard Clams, Mercenaria Mercenaria From The Elizabeth River, Va, Morris H. Roberts, Michael A. Unger

Reports

The Elizabeth River, contaminated with PAH, TBT, and heavy metals, is potentially home to a variety of estuarine invertebrates of commercial importance, notably oysters, hard clams, and crabs. Harvestable oysters have virtually disappeared from the system, but it has been rumored among commercial fishermen that a population of small (little neck to cherrystone) hard clams (Mercenaria mercenaria) exists within the Elizabeth River system. These clams are of serious interest to commercial clammers in the area as a previously unharvested source of market-size clams. Crabs of a harvestable size are also reasonably abundant throughout this river according to local fishermen.

The …

Virginia's Commercial Fishing Industry: Its Economic Performance And Contributions, James Kirkley

Reports

No abstract provided.

Bathymetric Line Chesapeake Bay, Virginia Institute Of Marine Science, Sav Program, Chesapeake Bay Program

Data

This is a GIS layer showing the 1- and -2-meter low water contours that were created in support of the SAV (Submerged Aquatic Vegetation) goals by the Chesapeake Bay Program.

The file was originally created in the mid – 1990s in ArcInfo as a coverage and then later converted to a shapefile. In 2010 the Shoreline Studies Program was given permission to use the data and convert it a KML format that can be viewed in Google earth.

This bathymetric contours file covers the Chesapeake bay in Maryland and Virginia.

Small Mammal Habitat Uses Of Two Natural And Created Wetlands In Southeastern Virginia, Amanda Mckenney Mueller

Dissertations, Theses, and Masters Projects

No abstract provided.

Distribution Of Freshwater Amphipoda In The Lake Matoaka/College Woods Area, Williamsburg, Virginia, Susan Alexandra Mahon

Dissertations, Theses, and Masters Projects

No abstract provided.

Development Of Monitoring Protocol For Created Wetlands : Project Summary For 1997, James E. Perry

Reports

Appx. 1. Annotated bibliography -- Appx. 2. Field data sheet - Appx. 3.Monitoring protocol manual for created wetlands: draft manual.

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1996, Robert J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagy

Reports

SA V distribution data in this report are presented and discussed based on the segmentation scheme adopted by the Chesapeake Bay Program (Flemer et al., 1983) and described briefly in the Methods section of this report. This zonation scheme (Upper, Middle, and Lower zones) for Chesapeake Bay, which accommodates the Chesapeake Bay Program segmentation boundaries, was adapted from that used in previous SAV distribution reports (i.e., Orth et al., 1994) and established by Orth and Moore ( 1982), then modified by Orth et al., ( 1989). The 1996 data were edgematched using ARC/INFO GIS software, as were all the historical …

The Influence Of Microstructure On The Thermal Degradation Behavior Of Poly(Vinyl Chloride), Hoang Vi Tran

Dissertations, Theses, and Masters Projects

No abstract provided.

Correspondence Between Environmental Gradients And The Assemblage Structure Of Littoral Fishes In The Tidal Portion Of Three Virginia Coastal Plain Rivers, Clifford Michael Wagner

Dissertations, Theses, and Masters Projects

No abstract provided.

The Synthesis Of 6a,6b-Dideoxy-6 A,6b-(9,10-Dicyanoanthracenyl-2,3-Dimethylene)-Beta-Cyclodextrin, Jonathan D. Tan

Dissertations, Theses, and Masters Projects

No abstract provided.

The Synthesis Of Benzophenone-3,5-Diacid Chloride For The Double Capping Of Beta-Cyclodextrin, Clyde Wesley Eargle

Dissertations, Theses, and Masters Projects

No abstract provided.

Targeting Wetland Preservation Areas For Compensatory Mitigation Utilizing A Gis Protocol, Lynn M. Dancy

Dissertations, Theses, and Masters Projects

No abstract provided.

Correlation Of Dynamic Dielectric Properties To Reaction Kinetics And Changing Mechanical Properties Of Epoxy Resins During Cure, Yunfei Wang

Dissertations, Theses, and Masters Projects

The principal objective of this paper is to describe how complex impedance, obtained from frequency dependent dielectric sensing technique, can be used as an effective diagnostic tool for in situ real-time investigation in the fabrication of thermoset structures.;Two epoxy systems (Pr500 from 3M and My720 from Ciba Geigy) with different functionality are characterized in terms of their dielectric, thermal, and rheological behavior. It is observed that there is a one to one relationship between Tg and conversion which is independent of cure temperature. The chemical kinetics of the reaction is satisfactorily described by an autocatalyzed reaction mechanism. The chemical rate …

Solar Infrared Relative Intensity Data From The Halogen Occultation Experiment, Philip Todd Spickler

Dissertations, Theses, and Masters Projects

Solar data from the Halogen Occultation Experiment (HALOE) were analyzed to determine the center-to-limb relative intensity and the vertical temperature profile for the quiet and active Sun over wavelengths from 2.4 to 10 {dollar}\mu{dollar}m. An algorithm that incorporated a nonlinear least squares procedure was developed that modeled the HALOE instrument during data acquisition. Data obtained from limb-to-limb scans along the solar equator on days of very low activity in May 1994 were analyzed to obtain coefficients of a function describing the relative intensity from center to limb. The relative intensities produced were precise to 0.1% (2{dollar}\sigma{dollar}) from the center to …

The Synthesis Of Reflective And Electrically Conductive Polyimide Films Via An In Situ Self-Metallization Procedure Using Silver(I) Complexes, Robin Elaine Southward

Dissertations, Theses, and Masters Projects

Optically reflective polyimide films have been prepared by the incorporation of silver(I) acetate and a {dollar}\beta{dollar}-diketone solubilizing agent, hexafluoroacetylacetone (HFAH), into a dimethylacetamide solution of the poly(amic acid) formed from {dollar}3,3\sp\prime,4,4\sp\prime{dollar}-benzophenonetetracarboxylic acid dianhydride (BTDA) and {dollar}4,4\sp\prime{dollar}-oxydianiline {dollar}(4,4\sp\prime{dollar}-ODA). Optically reflective and conductive polyimide films have been prepared by replacing the {dollar}\beta{dollar}-diketone (HFAH), with the less substituted {dollar}\beta{dollar}-diketone, trifluoroacetylacetone (TFAH). The former system has been both cast directly from the poly(amic acid) resin and cast from the poly(amic acid) resin onto a fully imidized {dollar}\rm BTDA/4,4\sp\prime{dollar}-ODA base (forming a metallized topcoat). Thermal curing of the silver(I)-containing poly(amic acid) leads to imidization with …

Global State Predicates In Rough Real-Time, Jean Ann Mayo

Dissertations, Theses, and Masters Projects

Distributed systems are characterized by the fact that the constituent processes have neither common memory nor a common system clock. These processes communicate solely via message passing. While providing a number of benefits such as increased reliability, increased computational power, and geographic dispersion, this architecture significantly complicates many of the tasks of software development and verification, including evaluation of the program state. In the case of distributed systems, the program state is comprised of the local states of the constituent processes, as well as the state of the channels between processes, and is called the global state.;With no common system …

Collision-Induced Secondary Electron And Negative Ion Emission From Metallic Surfaces, John Christopher Tucek

Dissertations, Theses, and Masters Projects

Absolute yields of negative ions and secondary electrons resulting from collisions of positive sodium ions (Na{dollar}\sp{lcub}+{rcub}){dollar} with polycrystalline aluminum (Al) and molybdenum (Mo) surfaces and the Mo (100) surface have been measured as a function of the oxygen (O) coverage, from none up to several monolayers, for impact energies, E {dollar}<{dollar} 500 eV. Negative oxygen ions (O{dollar}\sp{lcub}-{rcub}){dollar} are found to be the dominant sputtered negative ions and for the three surfaces at all O coverages and Na{dollar}\sp{lcub}+{rcub}{dollar} impact energies. The O{dollar}\sp{lcub}-{rcub}{dollar} and secondary electron yields share a common impact energy threshold at {dollar}\rm E\sb{lcub}th{rcub}\approx 50{dollar} eV, and both have a strong dependence on the oxygen coverage of the surface.;The kinetic energy distributions of the secondary electrons and sputtered O{dollar}\sp{lcub}-{rcub}{dollar} were determined as functions of O coverages and impact energies. The O{dollar}\sp{lcub}-{rcub}{dollar} distributions are characterized by a narrow, low energy peak (at {dollar}\sim{dollar}1-2 eV) followed by a low level, high energy tail. The secondary electrons have a narrow (FWHM {dollar}\sim{dollar} 1-2 eV) kinetic energy distribution, centered essentially at the same most probable kinetic energy as the ions. The shapes of the respective distributions and the most probable kinetic energies are essentially invariant with the impact energy, O coverage and the metal surface.;The results were analyzed in terms of conventional collision cascade model, but the calculation could not be fitted to the experimental results. An electronic excitation mechanism is proposed to augment the collision cascade and to provide a mechanism for secondary electron emission. In the model, adsorbed O, which resides on the surface essentially as O{dollar}\sp{lcub}-{rcub},{dollar} is collisionally excited into an (MO{dollar}\sp{lcub}-{rcub})\sp*{dollar} repulsive state, and as the O{dollar}\sp{lcub}-{rcub}{dollar} exits the surface along the surface potential energy curve, it can decay by emission of an electron to the metal or to the vacuum, or it can survive as an ion. The parameters of this model can be adjusted such that the calculated kinetic energy distribution, together with that of the collision cascade, can reasonably reproduce the experimental observations for the ions and provide a reasonable fit to the corresponding electron kinetic energy distributions as well.

Microstructures Of Poly(Vinyl Acetate) Studied By Nuclear Magnetic Resonance Spectroscopy, Hongyang Yao

Dissertations, Theses, and Masters Projects

Carbon-13 NMR spectroscopy was used to investigate the microstructures of poly(vinyl acetate) prepared by solution polymerization in benzene. A series of aromatic compounds was synthesized in order to model the structures formed via chain transfer to solvent. The peaks near 126.5 and 128.5 ppm in the spectra of the polymer samples were assigned to a 1-phenyl-(2n + 1)-multi-acetoxyalkane (where n = 1, 2, 3, etc.) microstructure. The concentration of that structure obtained from NMR spectra was correlated with the concentration calculated from reported kinetic data.;Chain transfer to benzene was shown to occur by addition of the macroradical to benzene, followed …

A Study Of Poly(Vinyl Chloride) Microstructure, Vadim Guennadievich Zaikov

Dissertations, Theses, and Masters Projects

High-field {dollar}\sp{lcub}13{rcub}{dollar}C and {dollar}\sp1{dollar}H NMR spectroscopies were used to investigate some unusual features of the molecular microstructure of poly(vinyl chloride) (PVC).;Several model monochloroalkenes were synthesized in order to determine {dollar}\sp{lcub}13{rcub}{dollar}C shift increments for the replacement of H by Cl at positions that are near an isolated internal double bond. These increments then were used to predict the {dollar}\sp{lcub}13{rcub}{dollar}C shifts of the internal allylic chloride structure in PVC. The predictions were not satisfactory, because, as expected, the increments were not additive.;It was shown that during conventional VC polymerization, the chloroallylic chain end (-CH{dollar}\sb2{dollar}CH=CHCH{dollar}\sb2{dollar}Cl) does not copolymerize with the monomer and is …

Discrete-Time Linear And Nonlinear Aerodynamic Impulse Responses For Efficient Cfd Analyses, Walter A. Silva

Dissertations, Theses, and Masters Projects

This dissertation discusses the mathematical existence and the numerical identification of linear and nonlinear aerodynamic impulse response functions. Differences between continuous-time and discrete-time system theories, which permit the identification and efficient use of these functions, will be detailed. Important input/output definitions and the concept of linear and nonlinear systems with memory will also be discussed. It will be shown that indicial (step or steady) responses (such as Wagner's function), forced harmonic responses (such as Theodorsen's function or those from doublet lattice theory), and responses to random inputs (such as gusts) can all be obtained from an aerodynamic impulse response function. …

Effects Of Spot (Leisostomus Xanthurus) Induced Bioturbation And Suspension On The Transport And Fate Of Sediments And A Particle-Associated Organic Contaminant, Michele A. Horvath

Dissertations, Theses, and Masters Projects

No abstract provided.

Spatial, Geostatistical, And Fractal Measures Of Seafloor Microtopography Across The Eel River Shelf, Off Northern California, George Randall. Cutter

Dissertations, Theses, and Masters Projects

No abstract provided.

New Data On Ichthyoplankton Of The Southwestern Pacific, Andrei V. Suntsov

Dissertations, Theses, and Masters Projects

No abstract provided.

Winter/Spring Steady-State Water Balances For A Palustrine Forested Wetland Located In Southeastern Virginia, Daniel Otis Redgate

Dissertations, Theses, and Masters Projects

No abstract provided.

On The Circulation Of The Northern North Sea And The Patagonian Shelf, Pablo D. Glorioso

Dissertations, Theses, and Masters Projects

The Northern North Sea and the Patagonian Shelf have similar characteristics, and their circulation is determined by strong tidal regimes, significant wind-driven flow, and by density gradients to a lesser degree. The influence of oceanic currents is notable in the Patagonian Shelf, where the Falkland Current flows along the shelf edge, but less important in the North Sea. While the North Sea is perhaps the most studied body of water in the world, the circulation of the Patagonian Shelf have remained fairly unknown. This study presents evidence of near-inertial oscillations in the Northern North Sea, not reported previously, derived from …