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William & Mary

Theses/Dissertations

2005

Articles 31 - 45 of 45

Full-Text Articles in Physical Sciences and Mathematics

Nursery Delineation, Movement Patterns, And Migration Of The Sandbar Shark, Carcharhinus Plumbeus, In The Eastern Shore Of Virginia Coastal Bays And Lagoons, Christina L. Conrath Jan 2005

Nursery Delineation, Movement Patterns, And Migration Of The Sandbar Shark, Carcharhinus Plumbeus, In The Eastern Shore Of Virginia Coastal Bays And Lagoons, Christina L. Conrath

Dissertations, Theses, and Masters Projects

The identification and delineation of nursery areas and areas of aggregation of north Atlantic sharks has been identified as an important information need for future management efforts. The objectives of this project were to use a fishery-independent method to study the overwintering area of juvenile sandbar sharks, to spatially delineate the Eastern Shore nursery area, and to examine movement patterns and space use within this nursery area. Data from 21 satellite transmitters attached to large juvenile sandbar sharks revealed that these sharks primarily occurred off the outer banks of North Carolina, at deeper depths and colder water temperatures during the …

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Sonar Sensor Interpretation For Ectogeneous Robots, Wen Gao Jan 2005

Sonar Sensor Interpretation For Ectogeneous Robots, Wen Gao

Dissertations, Theses, and Masters Projects

We have developed four generations of sonar scanning systems to automatically interpret surrounding environment. The first two are stationary 3D air-coupled ultrasound scanning systems and the last two are packaged as sensor heads for mobile robots. Template matching analysis is applied to distinguish simple indoor objects. It is conducted by comparing the tested echo with the reference echoes. Important features are then extracted and drawn in the phase plane. The computer then analyzes them and gives the best choices of the tested echoes automatically. For cylindrical objects outside, an algorithm has been presented to distinguish trees from smooth circular poles …

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The Interaction Between Stratification, Circulation, And Sediment Transport In A Partially-Mixed Estuary, Malcolm E. Scully Jan 2005

The Interaction Between Stratification, Circulation, And Sediment Transport In A Partially-Mixed Estuary, Malcolm E. Scully

Dissertations, Theses, and Masters Projects

Detailed field observations from the York River estuary, Virginia are used to examine the processes governing vertical density stratification and to evaluate the importance of spatial and temporal variations in turbulent mixing on estuarine dynamics and sediment transport. Contrary to previous findings that suggest wind stress acts predominantly as a source of energy to mix away stratification, this study demonstrates that the wind can play a more important role in "straining" the along-channel estuarine density gradient. as a result, down-estuary winds enhance the tidally-averaged vertical shear, which interacts with the along-channel density gradient to increase stratification. Conversely, up-estuary winds tend …

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Eye Pathologies Found In Several Decapod Crustaceans, Andrea M. Maniscalco Jan 2005

Eye Pathologies Found In Several Decapod Crustaceans, Andrea M. Maniscalco

Dissertations, Theses, and Masters Projects

No abstract provided.

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Estimation Of Annual And Semi-Annual Survival Of Adult Female Blue Crabs And Assessment Of The Effectiveness Of The Virginia Blue Crab Sanctuary Using Tag-Return Methodology, Debra M. Lambert Jan 2005

Estimation Of Annual And Semi-Annual Survival Of Adult Female Blue Crabs And Assessment Of The Effectiveness Of The Virginia Blue Crab Sanctuary Using Tag-Return Methodology, Debra M. Lambert

Dissertations, Theses, and Masters Projects

The blue crab fishery is the most valuable commercial fishery in Chesapeake Bay. The Chesapeake Bay stock recently experienced a period of overfishing, which has resulted in below average abundances, and the spawning stock has experienced an 84 % decline in biomass relative to levels in the late 1980s. The status of the stock is determined by comparing current estimates of mortality to biological reference points. Given the current focus on blue crab conservation, there is a need to obtain reliable, empirical estimates of survival to compare to the biological reference points. A tagging program was initiated on the terminally-molted, …

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Simulation Of Turbidity Maximums In The York River, Virginia, Jae-Il Kwon Jan 2005

Simulation Of Turbidity Maximums In The York River, Virginia, Jae-Il Kwon

Dissertations, Theses, and Masters Projects

Two of the most important processes in cohesive sediment transport, erosion rate and settling velocity, were the focus of this study. Settling velocities were estimated by the Owen tube method and the acoustic Doppler velocimeter (ADV) method. A novel erosion model, namely a constant erosion rate model, was implemented in a three-dimensional hydrodynamic eutrophication model (HEM-3D) to simulate the turbidity maximums in the York River system, Virginia. Two one-month periods of model simulations were conducted to mimic typical dry (November--December, 2001) and wet (March--April, 2002) seasons. In order to have enough data to verify the model, four slack water surveys …

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Predicting Future Shoreline Condition Based On Land Use Trends, Logistic Regression, And Fuzzy Logic, Lynne M. Dingerson Jan 2005

Predicting Future Shoreline Condition Based On Land Use Trends, Logistic Regression, And Fuzzy Logic, Lynne M. Dingerson

Dissertations, Theses, and Masters Projects

The lower Chesapeake Bay and adjacent coastal waters serve as the primary summer nursery areas for juvenile sandbar sharks (Carcharhinus plumbeus) in the Northwest Atlantic Ocean. The large population of juvenile sandbar sharks in this ecosystem benefits from increased food availability that fuels rapid growth and from limited exposure to large shark predators. Juvenile growth and survival is the most critical life history stage for sandbar sharks, and juvenile nursery grounds will continue to play an important role in the slow recovery of this stock from severe population declines due to overfishing. The goal of this study was to assess …

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Investigation Of The Life History Of The Cownose Ray, Rhinoptera Bonasus (Mitchill 1815), Donna S. Grusha Jan 2005

Investigation Of The Life History Of The Cownose Ray, Rhinoptera Bonasus (Mitchill 1815), Donna S. Grusha

Dissertations, Theses, and Masters Projects

No abstract provided.

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Physiological Ecology Of The Cultured Hard Clam, Mercenaria Mercenaria: A Case Study In Cherrystone Inlet, Virginia, Elizabeth Darrow Condon Jan 2005

Physiological Ecology Of The Cultured Hard Clam, Mercenaria Mercenaria: A Case Study In Cherrystone Inlet, Virginia, Elizabeth Darrow Condon

Dissertations, Theses, and Masters Projects

No abstract provided.

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Linking Framework Geology And Nearshore Morphology: Correlation Of Paleo-Channels With Shore-Oblique Sandbars And Gravel Outcrops, A. Grace Browder Jan 2005

Linking Framework Geology And Nearshore Morphology: Correlation Of Paleo-Channels With Shore-Oblique Sandbars And Gravel Outcrops, A. Grace Browder

Dissertations, Theses, and Masters Projects

No abstract provided.

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Shore-Oblique Bars, Nearshore Gravel Outcrops, And Their Correlation To Shoreline Change, Courtney A. Schupp Jan 2005

Shore-Oblique Bars, Nearshore Gravel Outcrops, And Their Correlation To Shoreline Change, Courtney A. Schupp

Dissertations, Theses, and Masters Projects

No abstract provided.

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Sources Of Sedimentary Organic Matter In The Mississippi River And Adjacent Gulf Of Mexico, Elizabeth J. Waterson Jan 2005

Sources Of Sedimentary Organic Matter In The Mississippi River And Adjacent Gulf Of Mexico, Elizabeth J. Waterson

Dissertations, Theses, and Masters Projects

The development of accurate carbon budgets, as well as global climate models with predictive capabilities, requires an understanding of the delivery and fate of terrigenous carbon in the environment. Understanding the extent to which estuarine and continental shelf processes alter carbon transfer between marine and terrestrial systems, including estimates of organic matter accumulation in coastal sediments, is poorly known. Organic carbon and nutrients exported to the adjacent Gulf of Mexico by the Mississippi River are influenced by biological and physical processes including remineralization, hydrodynamic sorting, seabed mixing and bioturbation, and burial. These complex processes make it difficult to know the …

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Synthesis And Characterization Of Hydrogen-Rich Polyimide Materials For Radiation Shielding, Sha Yang Jan 2005

Synthesis And Characterization Of Hydrogen-Rich Polyimide Materials For Radiation Shielding, Sha Yang

Dissertations, Theses, and Masters Projects

No abstract provided.

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Data Broadcast Scheduling: Models, Algorithms, And Analysis, Aaron Thomas Hawkins Jan 2005

Data Broadcast Scheduling: Models, Algorithms, And Analysis, Aaron Thomas Hawkins

Dissertations, Theses, and Masters Projects

Inherent in the field of data broadcasting is a communication problem in which a server is to transmit a subset of data items in response to requests received from clients. The intent of the server is to optimize metrics quantifying the quality of service the system provides. This method of data dissemination has proved to be an efficient means of delivering information in asymmetric environments demanding massive scalability. of critical importance in such a system is the algorithm used by the server to construct a schedule of item broadcasts.;Due to the real-time nature of this problem, performances of heuristics designed …

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Nuclear Magnetic Resonance Studies Of Relaxor Ferroelectrics, William J. Brouwer Jan 2005

Nuclear Magnetic Resonance Studies Of Relaxor Ferroelectrics, William J. Brouwer

Dissertations, Theses, and Masters Projects

This work is devoted to the study of local order in the ferroelectric PbSc1/2Ta1/2O3 (PST) and relaxor ferroelectric solid solutions (1-x)PbSC2/3W1/3O3-(x)PbTiO 3 (PSW-PT), (1x)PbSC2/3W1/3O3-(x)PbZrO 3 (PSW-PZ). Novel Magic Angle Spinning (MAS) Solid State Nuclear Magnetic Resonance (SS-NMR) experiments, including Multiple Quantum MAS (MQMAS) and Double Quantum Filtered Satellite Transition (DQF-STMAS), have been performed on these materials. A gamma function model is proposed for the distribution of quadrupole coupling constants, based on the Poissonian nature of atomic displacements. Moments for distributions may be subsequently extracted through agreement between experimental spectra and simulations implemented in novel programs. Simple crystal compound scandium oxide …

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