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Articles 1 - 30 of 39
Full-Text Articles in Physical Sciences and Mathematics
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 …
Search For Effects Beyond The Born Approximation In Polarization Transfer Observables In Ep Elastic Scattering, Mehdi Meziane
Search For Effects Beyond The Born Approximation In Polarization Transfer Observables In Ep Elastic Scattering, Mehdi Meziane
Dissertations, Theses, and Masters Projects
Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, GE/GM, obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange (TPEX) contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, this thesis reports measurements, of the GEp2gamma experiment, of polarization transfer observables in the elastic H ( e&ar;,e' p&ar; ) reaction for three different beam energies at a fixed squared momentum transfer Q² = 2.5 GeV², spanning a wide range …
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.
Mercury Exposure Assessment Of South River Floodplain Birds, Jincheng Wang
Mercury Exposure Assessment Of South River Floodplain Birds, Jincheng Wang
Dissertations, Theses, and Masters Projects
The studies involved in this thesis expanded the current project being conducted in Dr. Newman’s laboratory that aimed to define and quantify the impacts of mercury movement in contaminated aquatic and terrestrial food webs in the South River watershed (Virginia, USA). This expansion involved a two phase study, which fulfilled the requirement of a master thesis.
Previous research in our lab documented mercury biomagnification in the river itself and two floodplain locations on the South River watershed. Predictive models were built for mercury concentration in members of these food webs. These studies reached a preliminary conclusion that mercury biomagnification in …
The Impacts Of Shoreline Development On Shallow-Water Benthic Communities In The Patuxent River, Md, Cassie D. Bradley
The Impacts Of Shoreline Development On Shallow-Water Benthic Communities In The Patuxent River, Md, Cassie D. Bradley
Dissertations, Theses, and Masters Projects
Natural coastal habitats throughout Chesapeake Bay are increasingly threatened with shoreline modification due to population growth and rising rates of development. The replacement of these natural coastlines with hardened structures such as seawalls (bulkheads) and stone revetments (riprap) not only compromises vegetation at the land-water interface, but also can influence several elements of local aquatic food webs. Effects of these alterations have been well-studied with respect to fish assemblages and intertidal communities, particularly in conjunction with larger-scale watershed development, and recently, interest has shifted toward investigation of the effects of shoreline development on subtidal benthic infaunal communities.
This study evaluated …
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, …
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 …
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 …
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.
Molecular Marker Development For The Discrimination Of Atlantic And Pacific Blue Marlin (Makaira Nigricans), Laurie Sorenson
Molecular Marker Development For The Discrimination Of Atlantic And Pacific Blue Marlin (Makaira Nigricans), Laurie Sorenson
Dissertations, Theses, and Masters Projects
No abstract provided.
Net Microbial Activity, Vegetation Dynamics, And Ecosystem Function In Created And Natural Palustrine Forested Wetlands In Southeastern Virginia, Usa, Christian A. Hauser
Net Microbial Activity, Vegetation Dynamics, And Ecosystem Function In Created And Natural Palustrine Forested Wetlands In Southeastern Virginia, Usa, Christian A. Hauser
Dissertations, Theses, and Masters Projects
No abstract provided.
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.
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.
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 …
Development Of A Method For Quantifying The Air-Sea Flux Of Volatile Organic Carbon, Emily A. Jayne
Development Of A Method For Quantifying The Air-Sea Flux Of Volatile Organic Carbon, Emily A. Jayne
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 …
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.
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 …
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 …
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 …
A Measurement Of Neutrino Oscillations With Muon Neutrinos In The Minos Experiment, Stephen James Coleman
A Measurement Of Neutrino Oscillations With Muon Neutrinos In The Minos Experiment, Stephen James Coleman
Dissertations, Theses, and Masters Projects
Experimental evidence has established that neutrino flavor states evolve over time. A neutrino of a particular flavor that travels some distance can be detected in a different neutrino flavor state. The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline experiment that is designed to study this phenomenon, called neutrino oscillations. MI-NOS is based at Fermilab near Chicago, IL, and consists of two detectors: the Near Detector located at Fermilab, and the Far Detector, which is located in an old iron mine in Soudan, MN. Both detectors are exposed to a beam of muon neutrinos from the NuMI beamline, and …
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 …
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 …
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 …
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 …
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 …