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Articles 1 - 30 of 39
Full-Text Articles in Physical Sciences and Mathematics
Quantum Turbulence In Two Dimensional Bose-Einstein Condensates, Bo Zhang
Quantum Turbulence In Two Dimensional Bose-Einstein Condensates, Bo Zhang
Dissertations, Theses, and Masters Projects
We examine the energy cascades and quantum vortex structures in two-dimensional quantum turbulence through a special unitary time evolution algorithm. An early attempt at using the Lattice Boltzmann Method proved successful in correctly representing some features of the Nonlinear Schrodinger System (NLS), such as the phase shift following the one-dimensional soliton-soliton collision, as well as the two-dimentional modulation instability. However, to accurately evaluate NLS, the implicit Euler method is required to resolve the time evolution, which is computationally expensive. A more accurate and efficient method, the Quantum Lattice Gas model is employed to simulate the quantum turbulence governed by the …
Basal Food Web Dynamics In A Natural Eelgrass (Zostera Marina) Community: Cage-Free Field Experimentation, Matthew A. Whalen
Basal Food Web Dynamics In A Natural Eelgrass (Zostera Marina) Community: Cage-Free Field Experimentation, Matthew A. Whalen
Dissertations, Theses, and Masters Projects
The relative strength of bottom-up and top-down processes operating within food webs is a fundamental determinant of community structure and function. In marine systems, inconspicuous but often highly abundant invertebrate herbivores (mesograzers) are implicated as strong consumers of primary production and important prey for higher-order consumers. Because of their small size, however, mesograzer abundance is not easily manipulated in the field, which limits our ability to adequately assess their grazing impacts. Seagrass systems present a pressing need for the study of food web dynamics because anthropogenic nutrient and sediment inputs decrease the amount of light reaching seagrass leaves, which limits …
Fine Sediment Dynamics In Dredge Plumes, Stanley Jarrell Smith Ii
Fine Sediment Dynamics In Dredge Plumes, Stanley Jarrell Smith Ii
Dissertations, Theses, and Masters Projects
The research presented in this study is motivated by the need to improve predictions of transport and fate of cohesive sediments suspended during dredging operations. Two techniques are presented to quantify vertical sediment flux within dredge plumes. A mass-balance approach using an Acoustic Doppler Current Profiler (ADCP) is described and demonstrated to accurately estimate vertical mass flux and settling velocity for a suspension of fine sand from a dredged material placement operation. A new digital video settling column for simultaneous measurement of particle size and settling velocity is described and evaluated. The Particle Imaging Camera System (PICS) is a single-chambered, …
Synthesis And Fluorescence Studies Of Spirooxazine-Functionalized Poly(Phenylene Vinylene) Prepared Via Gilch Polymerization And Click Chemistry, Kathryn Anne Peth
Synthesis And Fluorescence Studies Of Spirooxazine-Functionalized Poly(Phenylene Vinylene) Prepared Via Gilch Polymerization And Click Chemistry, Kathryn Anne Peth
Dissertations, Theses, and Masters Projects
No abstract provided.
Production Of Cyclohexylene-Containing Diamines In Pursuit Of Novel Radiation Shielding Materials, Norah G. Bate
Production Of Cyclohexylene-Containing Diamines In Pursuit Of Novel Radiation Shielding Materials, Norah G. Bate
Dissertations, Theses, and Masters Projects
No abstract provided.
Microscopic Dynamics And Transport Of Hydrogen In Proton Conducting Oxides, Erik J. Spahr
Microscopic Dynamics And Transport Of Hydrogen In Proton Conducting Oxides, Erik J. Spahr
Dissertations, Theses, and Masters Projects
The microscopic motion of hydrogen in solid oxides plays an important role in defect migration and reaction processes. Understanding the vibrational dynamics associated with both hydrogen-oxygen (O-H) bonds and the surrounding ionic environment allows one to better characterize these fundamental interactions. This thesis presents a comprehensive investigation into the vibrational decay dynamics of O-H and O-D stretch modes in crystalline oxides using time-resolved infrared pump-probe spectroscopy.;Measurements of the vibrational lifetimes of hydrogen related local modes in potassium tantalate (KTaO3) and titanium dioxide (TiO2 ) show that the localized O-H vibration is very closely tied to proton transport. In KTaO3 we …
Thin Film And Chemical Ordering Effects On The Magnetic Anisotropy In Binary Alloys, Jonathan Ronald Skuza
Thin Film And Chemical Ordering Effects On The Magnetic Anisotropy In Binary Alloys, Jonathan Ronald Skuza
Dissertations, Theses, and Masters Projects
This dissertation presents various investigations into the structure-property correlations in highly anisotropic FePt and FePd thin films and nanostructures. These binary alloy thin films may exhibit long-range chemical ordering (e.g. L10), which induces a strong uniaxial magnetic anisotropy whose orientation is dependent on the ordering direction in the thin film. The chemical ordering, and hence the magnetic anisotropy, in these thin films can be controlled and tailored through sputter deposition and ion implantation conditions followed by subsequent processing. Two novel fabrication methods, x-ray rapid thermal annealing (XRTA) and heavy ion implantation, successfully demonstrate the ability to obtain highly anisotropic nanometer-sized …
Spatial And Temporal Analysis Of Fecal Coliform Distribution In Virginia Coastal Waters, Jie Huang
Spatial And Temporal Analysis Of Fecal Coliform Distribution In Virginia Coastal Waters, Jie Huang
Dissertations, Theses, and Masters Projects
The collection of fecal coliform (FC) monitoring data in shellfish growing waters is primarily to assess public health risks from consumption of contaminated product. The data is also commonly used to assess the potential sources and loads of bacteria entering the aquatic system. This project is intended to extend traditional methods of developing these assessments, by applying an inverse modeling approach to improve the estimation of FC loads in the small watersheds typically contributing to shellfish growing waters in Virginia. Many fecal contamination studies in lower Chesapeake Bay, Virginia, have conveniently focused on analyses over relatively small spatial and temporal …
Analysis And Approximation Of Optimal Co-Scheduling On Cmp, Yunlian Jiang
Analysis And Approximation Of Optimal Co-Scheduling On Cmp, Yunlian Jiang
Dissertations, Theses, and Masters Projects
In recent years, the increasing design complexity and the problems of power and heat dissipation have caused a shift in processor technology to favor Chip Multiprocessors. In Chip Multiprocessors (CMP) architecture, it is common that multiple cores share some on-chip cache. The sharing may cause cache thrashing and contention among co-running jobs. Job co-scheduling is an approach to tackling the problem by assigning jobs to cores appropriately so that the contention and consequent performance degradations are minimized. This dissertation aims to tackle two of the most prominent challenges in job co-scheduling.;The first challenge is in the computational complexity for determining …
Characterization Of Pa-11 Flexible Liner Aging In The Laboratory And In Field Environments Throughout The World, Arthur Jaeton Mitman Glover
Characterization Of Pa-11 Flexible Liner Aging In The Laboratory And In Field Environments Throughout The World, Arthur Jaeton Mitman Glover
Dissertations, Theses, and Masters Projects
Polyamide-11 (PA11) is a polymer of the Nylon family whose monomer is obtained from the castor bean, a renewable resource. It is widely used in offshore oil and gas production as a non-rigid flexible pipe liner, allowing for oil and gas transport from the wellhead to floating platforms for processing. The degradation of PA11 over time may lead to the pipe's failure, with possibly catastrophic results which include loss of life. Until now, the characterization of the degredative process has been limited to laboratory studies of the effects of water and temperature on the rate and degree of hydrolysis. In …
Measurement Of The Target-Normal Single-Spin Asymmetry A(N,Y) In The Deep Inelastic Region From The Reaction Helium-3 (E,E'), Joseph M. Katich
Measurement Of The Target-Normal Single-Spin Asymmetry A(N,Y) In The Deep Inelastic Region From The Reaction Helium-3 (E,E'), Joseph M. Katich
Dissertations, Theses, and Masters Projects
A first measurement of the inclusive target single-spin asymmetry, Any , has been performed in deep-inelastic scattering of electrons from a 3He target polarized normal to the electron scattering plane. This asymmetry is void of contributions at the Born level, and thus is a direct observable for two-photon physics. The experiment was performed in Hall A at Thomas Jefferson National Accelerator Facility from October 2008 through early February 2009.;The measurement is the first from a polarized neutron target. The final overall precision is several times better than previously existing SLAC proton data, and significantly extends the kinematic range over which …
Effective Large Scale Computing Software For Parallel Mesh Generation, Andriy Kot
Effective Large Scale Computing Software For Parallel Mesh Generation, Andriy Kot
Dissertations, Theses, and Masters Projects
Scientists commonly turn to supercomputers or Clusters of Workstations with hundreds (even thousands) of nodes to generate meshes for large-scale simulations. Parallel mesh generation software is then used to decompose the original mesh generation problem into smaller sub-problems that can be solved (meshed) in parallel. The size of the final mesh is limited by the amount of aggregate memory of the parallel machine. Also, requesting many compute nodes on a shared computing resource may result in a long waiting, far surpassing the time it takes to solve the problem.;These two problems (i.e., insufficient memory when computing on a small number …
On The Real-Time Performance, Robustness And Accuracy Of Medical Image Non-Rigid Registration, Yixun Liu
On The Real-Time Performance, Robustness And Accuracy Of Medical Image Non-Rigid Registration, Yixun Liu
Dissertations, Theses, and Masters Projects
Three critical issues about medical image non-rigid registration are performance, robustness and accuracy. A registration method, which is capable of responding timely with an accurate alignment, robust against the variation of the image intensity and the missing data, is desirable for its clinical use. This work addresses all three of these issues. Unacceptable execution time of Non-rigid registration (NRR) often presents a major obstacle to its routine clinical use. We present a hybrid data partitioning method to parallelize a NRR method on a cooperative architecture, which enables us to get closer to the goal: accelerating using architecture rather than designing …
Slow And Stored Light Under Conditions Of Electromagnetically Induced Transparency And Four Wave Mixing In An Atomic Vapor, Nathaniel Blair Phillips
Slow And Stored Light Under Conditions Of Electromagnetically Induced Transparency And Four Wave Mixing In An Atomic Vapor, Nathaniel Blair Phillips
Dissertations, Theses, and Masters Projects
The recent prospect of efficient, reliable, and secure quantum communication relies on the ability to coherently and reversibly map nonclassical states of light onto long-lived atomic states. A promising technique that accomplishes this employs Electromagnetically Induced Transparency (EIT), in which a strong classical control field modifies the optical properties of a weak signal field in such a way that a previously opaque medium becomes transparent to the signal field. The accompanying steep dispersion in the index of refraction allows for pulses of light to be decelerated, then stored as an atomic excitation, and later retrieved as a photonic mode. This …
The Development And Application Of An Antibody-Based Biosensor For The Detection Of The Petroleum-Derived Compounds, Candace Rae Spier
The Development And Application Of An Antibody-Based Biosensor For The Detection Of The Petroleum-Derived Compounds, Candace Rae Spier
Dissertations, Theses, and Masters Projects
Petroleum is one of the most important natural resources, but can also be problematic to environmental and human health. Petroleum is comprised of thousands of compounds, including polycyclic aromatic hydrocarbons (PAHs) and heterocycles, some of which are toxic and/or carcinogenic. Traditional analytical methods for environmental monitoring of low-level PAHs are time-consuming labor-intensive, and often laboratory-bound. Efforts to achieve timely, sensitive, and accurate analysis of PAHs in the field have become a priority for environmental research and monitoring. Antibody-based biosensors are presently being developed for environmental analysis. Anti-PAH antibody molecules can be coupled with electronic transducers to provide new biosensor technology …
Effects Of Dietary Mercury Exposure On Spatial Memory Of Zebra Finches, Taeniopygia Guttata, Amanda Mae Bessler
Effects Of Dietary Mercury Exposure On Spatial Memory Of Zebra Finches, Taeniopygia Guttata, Amanda Mae Bessler
Dissertations, Theses, and Masters Projects
No abstract provided.
The Influence Of Golf Course Landscapes On The Occupancy And Reproductive Success Of Eastern Bluebirds, Marie Louise Pitts
The Influence Of Golf Course Landscapes On The Occupancy And Reproductive Success Of Eastern Bluebirds, Marie Louise Pitts
Dissertations, Theses, and Masters Projects
No abstract provided.
The Total Synthesis Of The Lolium Alkaloids, Michael Todd Hovey
The Total Synthesis Of The Lolium Alkaloids, Michael Todd Hovey
Dissertations, Theses, and Masters Projects
No abstract provided.
Investigation Of Hg(Ii) Solution Speciation By Esi-Ms And Proton Nmr, Madeline R. Nestor
Investigation Of Hg(Ii) Solution Speciation By Esi-Ms And Proton Nmr, Madeline R. Nestor
Dissertations, Theses, and Masters Projects
No abstract provided.
Treatment Of Synchronizations In Compiling Fine-Grained Spmd-Threaded Programs For Cpu, Ziyu Guo
Treatment Of Synchronizations In Compiling Fine-Grained Spmd-Threaded Programs For Cpu, Ziyu Guo
Dissertations, Theses, and Masters Projects
No abstract provided.
Enhanced Field Emission From Vertically Oriented Graphene By Thin Solid Film Coatings, Michael Bagge-Hansen
Enhanced Field Emission From Vertically Oriented Graphene By Thin Solid Film Coatings, Michael Bagge-Hansen
Dissertations, Theses, and Masters Projects
Recent progress and a coordinated national research program have brought considerable effort to bear on the synthesis and application of carbon nanostructures for field emission. at the College of William and Mary, we have developed field emission arrays of vertically oriented graphene (carbon nanosheets, CNS) that have demonstrated promising cathode performance, delivering emission current densities up to 2 mA/mm2 and cathode lifetime > 800 hours. The work function ( & phis;) of CNS and other carbonaceous cathode materials has been reported to be &phis;∼4.5-5.1 eV. The application of low work function thin films can achieve several orders of magnitude enhancement of …
Effects Of Concurrent Phenathrene And Mycobacterium Marinum Exposure In The Zebrafish (Danio Rerio), Christopher M. Prosser
Effects Of Concurrent Phenathrene And Mycobacterium Marinum Exposure In The Zebrafish (Danio Rerio), Christopher M. Prosser
Dissertations, Theses, and Masters Projects
As a way to gain better understanding of how aquatic organisms respond within their natural environment, this dissertation set up a series of controlled laboratory experiments to investigate the effects of chemical and biological stressors on the zebrafish (Danio rerio). I performed a series of studies in which animals were simultaneously exposed to the toxicant phenanthrene, and infected with the bacterium Mycobacterium marinum. Unexpectedly, we found that at a high dose of phenanthrene (284 mug L-1) results in an antagonistic relationship between stressors with dually challenged fish having significantly higher survivorship than those exposed solely to phenanthrene. Dually challenged fish …
The Effects Of Hypoxia On Macrobenthic Production And Function In The Lower Rappahannock River, Chesapeake Bay, Usa, S. Kersey Sturdivant
The Effects Of Hypoxia On Macrobenthic Production And Function In The Lower Rappahannock River, Chesapeake Bay, Usa, S. Kersey Sturdivant
Dissertations, Theses, and Masters Projects
Human development has eroded Chesapeake Bay's health, resulting in an increase in the extent and severity of hypoxia (≤2 mg O2 l-1). The Bay's hypoxic zones have an adverse affect on community function and secondary production of macrobenthos. The production of macrobenthos is important as these fauna link energy transfer from primary consumers to epibenthic predators and demersal fish, and serve as the foremost pathway that carbon is recycled out of the sediment. Additionally, bioturbation, an essential macrobenthic function that causes the displacement and mixing of sediment particles, increases the quality of marine sediments. In the marine environment bioturbation is …
Deep-Pelagic (0-3000m) Fish Assemblage Structure Over The Mid-Atlantic Ridge In The Area Of The Charlie-Gibbs Fracture Zone, April B. Cook
Deep-Pelagic (0-3000m) Fish Assemblage Structure Over The Mid-Atlantic Ridge In The Area Of The Charlie-Gibbs Fracture Zone, April B. Cook
Dissertations, Theses, and Masters Projects
Only a miniscule fraction of the world’s largest volume of living space, the ocean’s mid-water biome, has ever been sampled. As part of the International Census of Marine Life field project Mid-Atlantic Ridge Ecosystems (MAR-ECO), a discrete-depth trawling survey was conducted in 2009 aboard the NOAA ship Henry B. Bigelow to examine the pelagic faunal assemblage structure and distribution over the Charlie-Gibbs Fracture Zone (CGFZ) of the northern Mid-Atlantic Ridge. This is the first MAR-ECO project aimed specifically at describing diel vertical migration as a distributional phenomenon. Discrete-depth sampling from 0-3000 m was conducted during both day and night in …
A Numerical Modeling Study Of Storm Surge And Inundation In The Chesapeake Bay During The November 2009 Mid-Atlantic Nor'easter, Jie Gao
Dissertations, Theses, and Masters Projects
No abstract provided.
The Effects Of Seagrass Species And Trophic Interactions In Experimental Seagrass Communities, Althea F. P. Moore
The Effects Of Seagrass Species And Trophic Interactions In Experimental Seagrass Communities, Althea F. P. Moore
Dissertations, Theses, and Masters Projects
No abstract provided.
Charmed Hadron Spectrum And Interactions, Liuming Liu
Charmed Hadron Spectrum And Interactions, Liuming Liu
Dissertations, Theses, and Masters Projects
Studying hadrons containing heavy quarks in lattice QCD is challenging mainly due to finite lattice spacing effects. to control the discretization errors, mQa is required to be much less than 1, where mQ is the quark mass and a is the lattice spacing. For currently accessible lattice spacings, the charm quark mass doesn't satisfy this requirement. One approach to simulate heavy quarks on the lattice is non-relativestic QCD, which treats heavy quark as a static source and expand the lattice quark action in powers of 1mQa . Unfortunately, the charm quark is not heavy enough to justify this expansion. An …
First-Principles Calculations Of Nuclear Magnetic Resonance Chemical Shielding Tensors In Complex Ferroelectric Perovskites, Daniel Lawrence Pechkis
First-Principles Calculations Of Nuclear Magnetic Resonance Chemical Shielding Tensors In Complex Ferroelectric Perovskites, Daniel Lawrence Pechkis
Dissertations, Theses, and Masters Projects
Nuclear magnetic resonance (NMR) spectroscopy is one of the most important experimental probes of local atomistic structure, chemical ordering, and dynamics. Recently, NMR has increasingly been used to study complex ferroelectric perovskite alloys, where spectra can be difficult to interpret. First-principles calculations of NMR spectra can greatly assist in this task. In this work, oxygen, titanium, and niobium NMR chemical shielding tensors, s&d4; , were calculated with first-principles methods for ferroelectric transition metal prototypical ABO3 perovskites [SrTiO3, BaTiO 3, PbTiO3 and PbZrO3] and A(B,B')O3 perovskite alloys Pb(Zr1/2Ti1/2)O3 (PZT) and Pb(Mg1/3Nb2/3)O3 (PMN). The principal findings are 1) a large anisotropy between …
Evaluating The Use Of Flow-Through Larval Culture For The Eastern Oyster, Crassostrea Virginica, Stephanie L. Reiner
Evaluating The Use Of Flow-Through Larval Culture For The Eastern Oyster, Crassostrea Virginica, Stephanie L. Reiner
Dissertations, Theses, and Masters Projects
One system used for bivalve mollusc culture is flowthrough larval culture, which provides a continuous flow of food and seawater to the tank. Flowthrough culture enables larvae to be reared at stocking densities up to 100 larvae/mL, a characteristic that should recommend it as the culture system of choice for the East coast; however, Eastern oyster larvae have never been tested in flowthrough culture, discouraging implementation of the system. The thesis objectives are designed to address questions regarding the survival, growth, competent period, cell consumption, growth efficiency, and cell selection of oyster larvae reared in flowthrough culture. The objectives are: …
Dynamics And Composition Of The Extracellular Polymeric Substances Produced By Benthic Microalgae: An In Situ 13c And 15n Approach, Stephanie Kara Salisbury
Dynamics And Composition Of The Extracellular Polymeric Substances Produced By Benthic Microalgae: An In Situ 13c And 15n Approach, Stephanie Kara Salisbury
Dissertations, Theses, and Masters Projects
The land-‐ocean margin is characterized by a shallow water column, which allows light to reach the benthos and supports a diverse community of benthic autotrophs. One group of benthic autotrophs, consisting of benthic diatoms, cyanobacteria and other photosynthetic microorganisms living near the sediment surface (i.e., benthic microalgae) accounts for a substantial amount of this primary production. Benthic microalgae are also tightly coupled to carbon and nutrient cycling processes carried out by the sediment bacterial community. Benthic microalgae exude complex biopolymers, called extracellular polymeric substances (EPS), which consist mainly of carbohydrates, but can contain proteins and nucleic acids. EPS serves multiple …