Physical Sciences and Mathematics Commons^™

Population Dynamics Of The Smooth Dogfish, Mustelus Canis, In The Northwest Atlantic, Christina L. Conrath

Dissertations, Theses, and Masters Projects

No abstract provided.

Synoptic Scale Climatic Forcing Of Multispecies Fish Recruitment Patterns In Chesapeake Bay, Robert J. Wood

Dissertations, Theses, and Masters Projects

Five fishery independent data sets were used to investigate multispecies fish recruitment patterns in Chesapeake Bay (1966--1997). Despite differences in sampling gear, sampled habitat, collection methods, and sampling sites, the strongest multispecies recruitment patterns within each data set (revealed by separate principal components analyses) depict a negative relationship between recruitment of spring spawning anadromous fishes and fall-winter continental shelf spawning species. This pattern dominates both low and high frequency components of the multispecies data. Because these two species groups utilize freshwater and oligohaline reaches of the Bay and its tributaries as springtime nursery areas, this Chesapeake Bay Anadromous-Shelf Spawner (CBASS) …

Structural Instabilities In Strontium Titanate From First-Principles Calculations, Christopher A. Lasota

Dissertations, Theses, and Masters Projects

For some time now, first-principles calculation methods have proven to be an effective tool for investigating the physics of condensed matter systems. The additional use of density functional theory (DFT) and the local density approximation (LDA) has permitted even complex materials to be studied on desktop workstations with remarkable success. The incorporation of linear response theory into these methods has extended their power, allowing investigation of important dynamical properties.;Contained within the following pages are the results of a first-principles study of SrTiO3. This transition metal oxide is often grouped with ferroelectric materials, due to its similar composition and perovskite structure. …

Low Damage Processing And Process Characterization, Xianmin Tang

Dissertations, Theses, and Masters Projects

Two novel plasma sources (one neutral source and one pulsed inductively coupled plasma source) and ashing process characterization were investigated. The primary goal was to characterize these source properties and develop corresponding applications. The study includes process damage assessment with these two sources and another continuous wave (13.56MHz) plasma source. A global average simulation of the pulsed discharges was also included.;The transient plasma density and electron temperature from the double probe analysis were compared with single Langmuir probe results with sheath displacement corrections in pulsed discharges (200Hz--10kHz). The equivalent resistance method can be used effectively to analyze these double probe …

Plasma Source Ion Implantation Of High Voltage Electrodes, Thomas Joseph Venhaus

Dissertations, Theses, and Masters Projects

Field emission and breakdown characteristics of high voltage, large area electrodes determine the performance of many vacuum-based electron sources. A corroborative project with the Thomas Jefferson National Accelerator Facility involves studying the behavior of such electrodes after nitrogen ion implantation. A Plasma Source Ion Implantation (PSII) facility is designed and constructed at William and Mary, and used to treat stainless steel electrodes. PSII is a novel implantation technique developed at the University of Wisconsin-Madison. A workpiece is submerged in a quiescent plasma of the species to be implanted. A series of high, negative voltages (30--100 kV) is applied to the …

Theoretical And Experimental Study Of Generation Mechanisms For Laser Ultrasound In Woven Graphite /Epoxy Composites With Translaminar Stitching, Adam D. Friedman

Dissertations, Theses, and Masters Projects

The aerospace industry is beginning to use advanced composite materials for primary load bearing structures and their failure mechanisms must be better understood to predict their behavior in service. The Combined Loads Tests (COLTS) facility is being constructed at the NASA Langley Research Center to characterize these failure mechanisms. Laser based ultrasonic NDE can monitor the samples during dynamic loading without interfering with the structural tests. However, the constraints of implementing laser ultrasound in a structures laboratory reduces the efficiency of the technique. The system has to be "eye-safe" because many people will be present during the structural tests. Consequently, …

Precision Measurements Of The Proton And Deuteron Polarized Structure Functions, Paul Mcconihay King Ii

Dissertations, Theses, and Masters Projects

Experiment E155 at the Stanford Linear Accelerator Center measured the longitudinal and transverse polarized deep-inelastic scattering asymmetries for the proton and deuteron using longitudinally-polarized electron beams with energies of 48.3 GeV and 38.8 GeV, respectively. The electron beam polarization was measured by Moller polarimetry to be 0.81 +/- 0.02. Dynamically-polarized solid 15N3 and 6Li2H were used as the target materials. The scattered electrons were detected in three independent spectrometers at 2.75??, 5.5??, and 10.5??, covering a kinematic range of 0.014 ≤ x ≤ 0.9 and 1.0(GeV/ c)2 ≤ Q2 ≤ 40(GeV/ c)2. The 10.5?? spectrometer was constructed for this experiment. …

Data Structures For The Analysis Of Large Structured Markov Models, Andrew S. Miner

Dissertations, Theses, and Masters Projects

High-level modeling formalisms are increasingly popular tools for studying complex systems. Given a high-level model, we can automatically verify certain system properties or compute performance measures about the system. In the general case, measures must be computed using discrete-event simulations. In certain cases, exact numerical analysis is possible by constructing and analyzing the underlying stochastic process of the system, which is a continuous-time Markov chain (CTMC) in our case. Unfortunately, the number of states in the underlying CTMC can be extremely large, even if the high-level model is "small". In this thesis, we develop data structures and techniques that can …

The Absorption Spectrum Of The Hydrogen Atom In Crossed Electric And Magnetic Fields, Dongmei Wang

Dissertations, Theses, and Masters Projects

This dissertation reports the theoretical interpretation of the measured absorption spectrum of hydrogen atoms in crossed electric and magnetic fields. Closed-orbit theory is modified from two-dimensions to three-dimensions to interpret the large scale structure in the absorption spectrum. A new computational method---a Chirped-Fourier-Transform---is developed to extract the closed orbits from an energy spectrum. A quantitative model is provided to calculate the continuum absorption. We prove that the observed continuum absorption is proportional to the flux of electrons along trajectories which escape within a short time. Einstein-Brillouin-Keller (EBK) quantization theory is applied to obtain an approximate energy spectrum. Our results prove …

Redistribution Of Rydberg States By Terahertz Radiation, Jonathan David Curley

Dissertations, Theses, and Masters Projects

We present the technique and results of our study of the redistribution of Rydberg states in barium by a half cycle pulse (HCP). A survey of previous research concerning the interaction of half cycle pulses with Rydberg atoms reveals a lack of experimental data in the area of state redistribution. This is primarily due to an inability to identify the redistributed states accurately using the currently available tool: selective field ionization (SFI). We present the limitations of SFI as a state identification tool. We then present a survey of isolated core excitation as a state identification tool, along with its …

Accelerating The Simulation Of Wireless Cellular Systems, Luiz Felipe Perrone

Dissertations, Theses, and Masters Projects

The simulation of comprehensive models for cellular wireless systems poses a computational burden of great proportions. When a sub-model for transmitter power level control is included in the simulation, a continuous process in discrete-time is introduced, requiring traditional execution to advance in small, regular time-steps. to accelerate these simulations, we propose the use of interval jumping, a novel technique which allows time to progress in adaptive, irregularly-sized jumps in time. The foundations for this mechanism are laid out in the light of the simulation of a complex simulation model which includes teletraffic, radio propagation, channel allocation, transmitter power control, and …

Surface Processing By Rfi Pecvd And Rfi Psii, Lingling Wu

Dissertations, Theses, and Masters Projects

An RFI plasma enhanced chemical vapor deposition (PECVD) system and a large-scale RF plasma source immersion ion implantation (PSII) system were designed and built to study two forms of 3-D surface processing, PECVD and PSII. Using the RFI PECVD system, Ti-6Al-4V substrates were coated with diamond-like carbon films with excellent tribological and optical properties. as an innovation, variable angle spectroscopic ellipsometry (VASE) was successfully applied for non-destructive, 3-D, large-area tribological coatings quality investigation.;Based on the experience with the RFI PECVD system, a large-scale RFICP source was designed and built for the PSIL Langmuir probe and optical emission spectroscopy studies indicated …

The Use Of Long-Lived Tracer Observations To Examine Transport Characteristics In The Lower Stratosphere, Gretchen Scott Lingenfelser

Dissertations, Theses, and Masters Projects

No abstract provided.

The Dehydrochlorination Mechanism Of The Internal Allylic Chloride Structure In Poly(Vinyl Chloride), Lynda B. Payne

Dissertations, Theses, and Masters Projects

No abstract provided.

Gis Data: Piankatank River, Virginia Shoreline Management Model, Center For Coastal Resources Management, Virginia Institute Of Marine Science

Data

The Shoreline Management Model is a GIS spatial model that determines appropriate shoreline best management practices using available spatial data and decision tree logic. Available shoreline conditions used in the model include the presence or absence of tidal marshes, beaches, and forested riparian buffers, bank vegetation cover, bank height, wave exposure (fetch), nearshore water depth, and proximity of coastal development to the shoreline. The model output for shoreline best management practices is displayed in the locality Comprehensive Map Viewer. One GIS shapefile is developed that describes two arcs or lines representing practices in the upland area and practices at the …

Effects Of Polychlorinated Biphenyl Exposure On Development And Sexual Differentiation In Ranid Tadpoles, Mary J. Rybitski

Dissertations, Theses, and Masters Projects

The effects of AroclorRTM1242 exposure on developing amphibians were examined by exposing southern leopard frogs, Rana sphenocephala, to a contaminated diet throughout the larval period. Treatment groups consisted of an untreated control, a solvent control, 17beta-estradiol, and three PCB doses (10, 100, and 1000 mug/g). PCB accumulation and biotransformation were examined. Effects of PCB exposure on metamorphosis and sexual differentiation were assessed. PCB accumulation was not statistically different between the egg masses. Levels of PCBs in the tissues differed in a dose related manner. Within treatments, body weight appeared to be the major factor correlated with PCB concentration. Congener patterns …

Semantic Software Scouts For Information Retrieval, John J. Rehder

Dissertations, Theses, and Masters Projects

A new concept for information storage and retrieval is proposed that links chunks of information within and among documents based on semantic relationships and uses those connections to efficiently retrieve all the information that closely matches the user's request. The storage method is semantic hypertext, in which conventional hypertext links are enriched with semantic information that includes the strength and type of the relationship between the chunks of information being linked. A retrieval method was devised in which a set of cooperating software agents, called scouts, traverse the connections simultaneously searching for requested information. By communicating with each other and …

Studies In Hard Pion Photoproduction, Christian Jens Wahlquist

Dissertations, Theses, and Masters Projects

The production of high transverse momenta mesons via polarized photoproduction can be a means of determining the parton structure of the target. at the regions of highest transverse pion momenta, kT, it can be shown that short distance, direct, pion production dominates and is sensitive to the polarized quark distributions. as the produced pions transverse momenta decreases the importance of pions produced through fragmentation following photon-gluon fusion increases. This process give us sensitivity to the form of the polarized gluon distribution. Both processes are calculable with perturbative Quantum Chromodynamics (pQCD) due to the high kT of the pion produced. Numerical …

The Attempted Synthesis Of 4,4'-Bis(Dimethylamino)Azobenzene-3,3'-Disulfonylchloride As A Cap For Beta-Cyclodextrin, Katherine M. Ross

Dissertations, Theses, and Masters Projects

No abstract provided.

Answering Local Wetlands Boards Needs Regarding Guidance In Investigating Wetlands Violations : Final Report To The United States Environmental Protection Agency, Wetlands Protection State Development Project Period July 1, 1998-June 30, 2000, Kirk J. Havens, Bartlett N. Theberge

Reports

No abstract provided.

The Crest, Winter 2000, Virginia Institute Of Marine Science

Reports

Table of Contents:

• VIMS Director Invited to Speak in China Finfish Aquaculture Updates
• Riparian Buffer Demonstration Sites
• Bay-Sustaining Life Bustling On The Bottom
• New Technology Boosts Billfish Survivability Research
• A Profile of the Aquaculture Molecular Genetics Laboratory: Probing the DNA of the Oyster and its Parasite Perkinsus marinus (Dermo)
• Origin of MSX in Eastern Oyster Documented by VIMS Scientists
• Guess What Really Takes A Blue Crab's Breath Away?
• Catch and Release Symposium Tackles Tough Salt Water Fishing Issues
• Teaching Marsh Update
• Oyster Reef Habitat Restoration Book now Available
• Future Alterations to the Yangzi Estuary

The Virginia Wetlands Report Vol. 14, No. 3, Virginia Institute Of Marine Science

Virginia Wetlands Reports

• Book Review Salt Tide: Cycles and Currents of Life Along the Coast. Anne Newsom
• Dragonflies: Hawks of the Insect World! Kirk Havens
• Corp of Engineers Maneuvering to Adjust James River Dredging Restrictions.Tom Barnard
• New Scholarship Housed at VIMS Online Fauna and Flora Data in Virginia. Marcia Berman
• Natural Lighting: Colonial Necessity is Today’s Craft. Pam Mason

Investigations Of Offshore Beach Sands : Virginia Beach And Sandbridge, Virginia, C. S. Hardaway, C. H. Hobbs Iii, D. A. Milligan

Reports

The City of Virginia Beach is faced with an ongoing problem of erosion along its ocean beaches. The "Resort Strip," the backbone of beach-going tourism in the Commonwealth, must be renourished annually. Steel bulkheads or seawalls have been constructed along most of the 7 km (4.5 mile) ocean shoreline of Sandbridge, a semi-private, ocean-side community. The City is looking for beach material to reestablish its sandy coast. Maintaining a protective and recreational beach is the_primary goal in both locales.

Previous sources of sand for the "Resort Strip" have been upland borrow pits that either have closed or are located too …

Remote Sensing Of Natural Areas: Procedures And Considerations For Assessing Vegetation Composition Change, Land Development, And Erosion, Jason Goldberg, James Perry, John Anderson, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Shoreline Management In Chesapeake Bay, C. Scott Hardaway Jr., Robert J. Byrne

Reports

This document describes and illustrates specific, practical responses to shoreline management issues. We will begin with a look at the evolution of the Chesapeake Bay and its ongoing, long-term processes. We will proceed to a discussion of the daily, physical mechanisms that affect shoreline change and the topics professionals address in evaluating sites. We will then discuss strategies for managing shorelines, such as bulkheads, seawalls, revetments, groins, breakwaters, beach nourishment, and marsh fringes, as well as taking no action. Finally, we will give you a framework to apply these ideas in terms of the physical environment at the site and …

What Does It Take To Become A Marine Scientist?, Virginia Institute Of Marine Science

Reports

Note: This material may not meet current educational standards and is presented as part of the Institute's historical publications.

Report On Spectral Wave Modeling : Extended Study Of The Effects Of Sand Mining On The Wave Regime At Sandbridge, Virginia - Comparison Of Results Using A Phase-Revolving And A Phase-Averaging Spectral Wave Model (Ref/Dif S And Swan), John D. Boon, Sung Chan Kim

Reports

In an earlier report (Boon, 1998), findings were presented from a wave modeling study whose purpose was to investigate the effects of sand mining on the nearshore wave regime at Sandbridge, Virginia (Fig . 1). Using a phase-resolving spectral wave model, REF/DIF S (Kirby and Ozkan, 1992), a representative set of hypothetical storm waves was propagated across a 20 km section of the inner shelf from approximately the 20 m depth contour offshore to the 11 m depth contour inshore . Subsequent simulations were then made that tested local effects of shoaling and refraction on wave heights within a fine-scale …

Ecological Functions Of Constructed Oyster Reefs Along An Environmental Gradient In Chesapeake Bay: Final Report, Fx O'Beirn, Mark Luckenbach, Roger L. Mann, J Harding, J Nestlerode

Reports

Oyster reef habitat restoration within the Chesapeake Bay has as its objectives not only the enhancement of the commercially important oyster stocks, but also the restoration of associated assemblages of organisms and, most importantly, the restoration of ecological functions associated with natural reef communities. Despite our efforts to date, many uncertainties still exist with respect to achieving these restoration goals. These include long-term information on the temporal sequence of community development on new reef substrate, evaluating oyster recruitment patterns (a) across restored reef systems and (b) in relation to resident brood stocks.

In this study we sought to characterize the …

The Virginia Wetlands Report Vol. 14, No. 2, Virginia Institute Of Marine Science

Virginia Wetlands Reports

• Virginia Horseshoe Crab Management Update. Tom Barnard and Lyle Varnell
• Applications for Wetlands Restoration in the Elizabeth River Watershed. Marcia Berman
• Historic Wetland Loss in the Elizabeth River. Walter I. Priest, III
• Recorded History was Revolutionized By a Wetland Plant. Pam Mason

The Crest, Summer 1999, Virginia Institute Of Marine Science

Reports

Table of Contents:

• New Research Aquarium System
• Finfish Aquaculture at VIMS
• Virginia Creates State Research Reserve System
• Pollution-Laden Sediments In Constant Flux
• Survey of Mid-Atlantic Sea Scallop Closed Areas
• Pfiesteria Update
• New Computer Program Helps Planners Balance Growth, Protection
• Virginia Sea Grant to Administer Commercial Fishery Resource Program
• VIMS Stranded Sea Turtle Project Underway Coastal Sediments Offer Clues to Climate Change, Pollution
• Seemingly Barren Habitat Proves Vital for Economically Important Virginia Fish (juvenile flounder)