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Articles 1 - 30 of 52
Full-Text Articles in Physical Sciences and Mathematics
Magnetohydrodynamic Turbulence: The Development Of Lattice Boltzmann Methods For Dissipative Systems, Angus Ian Duncan Macnab
Magnetohydrodynamic Turbulence: The Development Of Lattice Boltzmann Methods For Dissipative Systems, Angus Ian Duncan Macnab
Dissertations, Theses, and Masters Projects
Computer simulations of complex phenomena have become an invaluable tool for scientists in all disciplines. These simulations serve as a tool both for theorists attempting to test the validity of new theories and for experimentalists wishing to obtain a framework for the design of new experiments. Lattice Boltzmann Methods (LBM) provide a kinetic simulation technique for solving systems governed by non-linear conservation equations. Direct LBMs use the linearized single time relaxation form of the Boltzmann equation to temporally evolve particle distribution functions on a discrete spatial lattice. We will begin with a development of LBMs from basic kinetic theory and …
Diet Of The Sandbar Shark, Carcharhinus Plumbeus, In Chesapeake Bay And Adjacent Waters, Julia K. Ellis
Diet Of The Sandbar Shark, Carcharhinus Plumbeus, In Chesapeake Bay And Adjacent Waters, Julia K. Ellis
Dissertations, Theses, and Masters Projects
The sandbar shark, Carcharhinus plumbeus, is the most abundant large coastal shark in the temperate and tropical waters of the northwest Atlantic Ocean. The Chesapeake Bay, Virginia and adjacent waters serve as a nursery ground for C. plumbeus as well as many other fauna. Characterizing the diet of a higher trophic level predator such as the sandbar shark sheds light on a small portion of the temporally and spatially complex food web in the Bay. This study describes the diet of the sandbar shark, highlighting differences in diet within various portions of the nursery area, as well as ontogenetic changes …
Inverse Model Analysis Of Plankton Food Webs In The North Atlantic And Western Antarctic Peninsula, Robert M. Daniels
Inverse Model Analysis Of Plankton Food Webs In The North Atlantic And Western Antarctic Peninsula, Robert M. Daniels
Dissertations, Theses, and Masters Projects
No abstract provided.
Persistent Organic Pollutants At The Base Of The Antarctic Marine Food Web, Amy Lee Chiuchiolo
Persistent Organic Pollutants At The Base Of The Antarctic Marine Food Web, Amy Lee Chiuchiolo
Dissertations, Theses, and Masters Projects
No abstract provided.
Bioavailability Of Polybrominated Diphenyl Ethers (Pbdes) In Biosolids And Spiked Sediment To The Aquatic Worm Lumbriculus Variegatus, Serena Ciparis
Bioavailability Of Polybrominated Diphenyl Ethers (Pbdes) In Biosolids And Spiked Sediment To The Aquatic Worm Lumbriculus Variegatus, Serena Ciparis
Dissertations, Theses, and Masters Projects
No abstract provided.
Metal Concentrations In Deep-Sea Mussels From A Hydrothermal Vent And Cold Seep, Shana Rapoport
Metal Concentrations In Deep-Sea Mussels From A Hydrothermal Vent And Cold Seep, Shana Rapoport
Dissertations, Theses, and Masters Projects
No abstract provided.
A Parallel Two Dimensional Delaunay Decoupling Method, Leonidas Linardakis
A Parallel Two Dimensional Delaunay Decoupling Method, Leonidas Linardakis
Dissertations, Theses, and Masters Projects
No abstract provided.
Polycyclic Aromatic Hydrocarbon Sources And Distribution In An Urban Estuary, Shelby E. Walker
Polycyclic Aromatic Hydrocarbon Sources And Distribution In An Urban Estuary, Shelby E. Walker
Dissertations, Theses, and Masters Projects
As part of the assessment of the potential risk posed by contaminated sediments to the environment and human health, the United States Environmental Protection Agency (USEPA) is developing a set of sediment quality criteria (SQC) that are based on equilibrium partitioning (EqP). While EqP theory has often been used to predict contaminant concentrations within a factor of two for a range of sediment types, substantial deviations from predicted values have also been documented. The objective of this research was to evaluate the influence of PAH source on PAH sediment-pore water partitioning and distribution in sediments. The Elizabeth River is one …
Socioeconomic Effects Of Area Management And The Potential For Community-Based Co-Management: A Case Study Of The Atlantic Sea Scallop Fishery, Winifred L. Ryan
Socioeconomic Effects Of Area Management And The Potential For Community-Based Co-Management: A Case Study Of The Atlantic Sea Scallop Fishery, Winifred L. Ryan
Dissertations, Theses, and Masters Projects
Community concerns regarding natural resource management may be addressed in several forms. The community may participate as part of the public in the management process; community concerns may be included in social impact assessment; and communities may directly participate as managers of resources whether on their own or in conjunction with higher levels of government. In fisheries, typically community concerns are addressed through social impact assessment which is perceived to be lacking in social theory, history, and often effect (Boggs 1994, Little and Krannich 1989). More recent activity and newer regulations show success with co-management, a management regime of shared …
Time-Resolved Optical Studies Of Colossal Magnetoresistance And Charge -Density Wave Materials, Yuhang Ren
Time-Resolved Optical Studies Of Colossal Magnetoresistance And Charge -Density Wave Materials, Yuhang Ren
Dissertations, Theses, and Masters Projects
This thesis presents measurements of collective modes and ultrafast carrier relaxation dynamics in charge-density-wave (CDW) conductors and colossal magnetoresistance (CMR) manganites. A femtosecond laser pump pulse excites a broad frequency spectrum of low-energy collective modes and electron-hole pairs thereby changing its optical properties. The low-energy collective excitations and quasiparticle relaxation and recombination processes are monitored by measuring the resulting photoinduced absorption as a function of probe pulse wavelength and time delay.;A general model was developed for the photogeneration and detection mechanism of collective modes based on light absorption in two-color pump-probe experiments. A broad spectrum of collective modes (phasons and …
Chemical Bonding In Hard And Elastic Amorphous Carbon-Nitride Films, W. Jason Gammon
Chemical Bonding In Hard And Elastic Amorphous Carbon-Nitride Films, W. Jason Gammon
Dissertations, Theses, and Masters Projects
In this study, the chemical bonding in hard and elastic amorphous carbon nitride (a-CNx) films is investigated with x-ray photoelectron spectroscopy (XPS) and 15N, 13C, and 1H nuclear magnetic resonance (NMR) spectroscopy. The films were deposited by DC Magnetron sputtering in a pure nitrogen discharge on Si(001) substrates at 300--400??C. Nanoindentation measurements reveal an elastic modulus of ∼50 GPa and a hardness of ∼5 GPa, thus confirming our films are highly elastic but resist plastic deformation.;Our 13C NMR study demonstrates the absence of sp 3-bonded carbon in this material. Collectively, our N(1s) XPS, 13C NMR, and 15N NMR data suggest …
An Analysis Of Wetland Patterns And Functions At The Watershed And Sub-Watershed Scales, With *Policy Applications, Jennifer Newton Bissonnette
An Analysis Of Wetland Patterns And Functions At The Watershed And Sub-Watershed Scales, With *Policy Applications, Jennifer Newton Bissonnette
Dissertations, Theses, and Masters Projects
This dissertation addresses the need to define potential impacts of recent and proposed changes in federal wetland regulation in a quantifiable manner. Consideration was made not only of total wetland acreage and wetland types that could sustain losses, but also to categorize the effect such losses would have in terms of wetland functions, at the watershed scale. This work took a Geographic Information Systems (GIS) approach, and included employing a best-professional judgment model for scoring habitat, water quality and flood attenuation functions to determine potential cumulative impacts; a water quality study which related wetland and watershed variables to nutrient and …
Laboratory Oxide Coatings: Physical Form And Surface Chemistry, Kea U. Duckenfield
Laboratory Oxide Coatings: Physical Form And Surface Chemistry, Kea U. Duckenfield
Dissertations, Theses, and Masters Projects
The impact of dissolved trace metals on aquatic ecosystems and human health is controlled by sorption, i.e., binding to the surfaces of environmental particles. Since many environmental particles are coated with highly reactive substances, and since discrepancies in trace metal sorption behavior persist between oxides developed in the laboratory and environmental oxide phases, it was hypothesized that the physical form of oxide coatings may influence the chemical properties of the coated particle. Therefore, relationships between the physical forms of several different Fe(III) oxide coatings and the Cu(II) sorption behavior of the coated solids were investigated in comparison with the component …
Availability Of Humic Nitrogen To Phytoplankton, Jason Holt See
Availability Of Humic Nitrogen To Phytoplankton, Jason Holt See
Dissertations, Theses, and Masters Projects
The chemical, physical, and biological factors affecting the bioavailability of humic nitrogen (N) to coastal phytoplankton were examined. Historically, humic substances have largely been considered biologically refractory, and humic-N is though to be unavailable biologically without prior oxidation via photochemical cleavage or remineralization by bacteria. This is due in part to the high aromaticity and low N content of humic substances. This dissertation investigates whether these assumptions are valid, and whether humic substances may be a more important source of N to the coastal phytoplankton community than previously believed. The research consisted of four main parts. First, changes in the …
Microbial Dynamics And Biogeochemistry In The North Pacific Subtropical Gyre, Matthew J. Church
Microbial Dynamics And Biogeochemistry In The North Pacific Subtropical Gyre, Matthew J. Church
Dissertations, Theses, and Masters Projects
The research presented in this dissertation describes the influence of planktonic bacterial growth on upper ocean organic matter dynamics in the North Pacific Subtropical Gyre (NPSG). Examination of the temporal dynamics in dissolved organic matter (DOM) was coupled with investigations that targeted the influence of heterotrophic bacterial production (HBP) on organic matter fluxes in the NPSG. Nine cruises to the Hawaii Ocean Time-series field site Station ALOHA revealed that HBP accounted for a large flux of organic carbon in the upper ocean of the NPSG. HBP was significantly enhanced by sunlight, with photoenhancement of HBP accounting for 3.2 mol C …
A Theoretical And Experimental Study Of Allee Effects, Joanna Gascoigne
A Theoretical And Experimental Study Of Allee Effects, Joanna Gascoigne
Dissertations, Theses, and Masters Projects
Allee effects occur when fitness suffers at low population size or density. This can lead to reduced population growth rate and a critical density below which extinction occurs. Allee effects can occur in reproduction or survival. Critical densities are higher in reproductive Allee effects than in juvenile survival Allee effects, making reproductive Allee effects more severe (higher extinction probability). In terms of the critical Allee effect threshold, reproductive Allee effects are more severe in r-selected populations, while juvenile survival Allee effects are more severe in K-selected populations. For populations with negative density dependence, there is a maximum critical Allee threshold, …
A Genetic Investigation Of Population Structure And Phylogenetics Of The Benthic Polychaete Paraprionospio Pinnata In Chesapeake Bay, Julie Beck Stubbs
A Genetic Investigation Of Population Structure And Phylogenetics Of The Benthic Polychaete Paraprionospio Pinnata In Chesapeake Bay, Julie Beck Stubbs
Dissertations, Theses, and Masters Projects
No abstract provided.
Effects Of Sediment Characteristics On The Distribution Of Fiddler Crabs (Uca Spp) At Goodwin Island, Virginia, Landon Alan Ward
Effects Of Sediment Characteristics On The Distribution Of Fiddler Crabs (Uca Spp) At Goodwin Island, Virginia, Landon Alan Ward
Dissertations, Theses, and Masters Projects
No abstract provided.
Synthetic And Mechanistic Studies Of Poly(Vinyl Chloride) And Some Other Chlorinated Polymers, Xianlong Ge
Synthetic And Mechanistic Studies Of Poly(Vinyl Chloride) And Some Other Chlorinated Polymers, Xianlong Ge
Dissertations, Theses, and Masters Projects
Unlike vinyl chloride, 1,2-dichloroethylene (DCE) experienced dimerization under free-radical conditions. Chain transfer to DCE by beta-Cl elimination was shown to be the major reason for its nonpolymerization.;During the chlorination of alkyl chlorides with molecular chlorine, the involvement of a bridged intermediate led to the formation of vicinal chlorides as the major products. The yields of geminal chlorides increased significantly in the presence of solvents that form complexes with chlorine atoms, but such solvents also decreased the reactivity of the chlorination. Thus the chlorination of poly(vinyl chloride) (PVC) in the presence of complexing solvents was not a useful method for the …
Power Considerations For Memory-Related Microarchitecture Designs, Zhichun Zhu
Power Considerations For Memory-Related Microarchitecture Designs, Zhichun Zhu
Dissertations, Theses, and Masters Projects
The fast performance improvement of computer systems in the last decade comes with the consistent increase on power consumption. In recent years, power dissipation is becoming a design constraint even for high-performance systems. Higher power dissipation means higher packaging and cooling cost, and lower reliability. This Ph.D. dissertation will investigate several memory-related design and optimization issues of general-purpose computer microarchitectures, aiming at reducing the power consumption without sacrificing the performance. The memory system consumes a large percentage of the system's power. In addition, its behavior affects the processor power consumption significantly. In this dissertation, we propose two schemes to address …
Domain And Type Enforcement In Linux, Serge Edward Hallyn
Domain And Type Enforcement In Linux, Serge Edward Hallyn
Dissertations, Theses, and Masters Projects
Domain and Type Enforcement (DTE) is a simple and well-known access control system, which has been used at the microkernel level in SPIN, the kernel level in Unix, and the user-space library level in CORBA. This work implements DTE as a Linux Security Module, and provides tools for the composition and analysis of policies. The goal is to bring Mandatory Access Control in Linux to the level of ease of use of cryptography tools and libraries.;Tools have been created to edit DTE policies and query transitions through different privilege levels. A subtle modification of the Bell LaPadula (BLP) access control …
Comparison Of Mussel-Bed Faunas At Blake Ridge And Florida Escarpment Seeps, Kathleen Elizabeth Knick
Comparison Of Mussel-Bed Faunas At Blake Ridge And Florida Escarpment Seeps, Kathleen Elizabeth Knick
Dissertations, Theses, and Masters Projects
No abstract provided.
Relationships Between Watershed Characteristics And Base Flow Nutrient Discharges To Eastern Shore Coastal Lagoons, Virginia, Jennifer Wu Stanhope
Relationships Between Watershed Characteristics And Base Flow Nutrient Discharges To Eastern Shore Coastal Lagoons, Virginia, Jennifer Wu Stanhope
Dissertations, Theses, and Masters Projects
No abstract provided.
Taxonomic Composition And Growth Rates Of Phytoplankton Assemblages At The Subtropical Convergence East Of New Zealand, Liza M. Delizo
Taxonomic Composition And Growth Rates Of Phytoplankton Assemblages At The Subtropical Convergence East Of New Zealand, Liza M. Delizo
Dissertations, Theses, and Masters Projects
No abstract provided.
Analysis Of Prey Selection In Black Skimmer, Rynchops Niger, Adults And Chicks Using Continuous Video Monitoring, Renae Joyce Held
Analysis Of Prey Selection In Black Skimmer, Rynchops Niger, Adults And Chicks Using Continuous Video Monitoring, Renae Joyce Held
Dissertations, Theses, and Masters Projects
No abstract provided.
A Genetic Analysis Of The Intraspecific Relationships Of Tropical Marine Shorefishes Common To Bermuda And The Southeastern Atlantic Coast Of The United States, Kelly R. Johnson
A Genetic Analysis Of The Intraspecific Relationships Of Tropical Marine Shorefishes Common To Bermuda And The Southeastern Atlantic Coast Of The United States, Kelly R. Johnson
Dissertations, Theses, and Masters Projects
No abstract provided.
Controls On The Delivery Of Fluvial Sediment To The Coastal Ocean: The Salinas River, California, Katherine L. Farnsworth
Controls On The Delivery Of Fluvial Sediment To The Coastal Ocean: The Salinas River, California, Katherine L. Farnsworth
Dissertations, Theses, and Masters Projects
To estimate delivery to the coastal ocean, a global river database was assembled. An estimated 35,000 km3 of freshwater, 4 * 10 6 tonnes of dissolved solids and 18.6 * 106 tonnes of suspended sediment are delivered annually. The global delivery of fluvial water and sediment, both suspended and dissolved, is dominated by Southeast Asia, due to the unique climatic, geologic and geomorphic character of the rivers in this region. Over 30% of the global freshwater and dissolved solid discharge, and an astounding 70% of the suspended sediment originate in this region. The Salinas River, central California, was the focus …
Silica Supported Copper Complexes And Their Biomimetic Activities, Jun Wang
Silica Supported Copper Complexes And Their Biomimetic Activities, Jun Wang
Dissertations, Theses, and Masters Projects
No abstract provided.
Mechanistic Studies On Chlorinated Polymeric Systems, Jing Zhang
Mechanistic Studies On Chlorinated Polymeric Systems, Jing Zhang
Dissertations, Theses, and Masters Projects
No abstract provided.
Location Management In A Mobile Object Runtime Environment, Andriy Fedorov
Location Management In A Mobile Object Runtime Environment, Andriy Fedorov
Dissertations, Theses, and Masters Projects
No abstract provided.