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Articles 1 - 30 of 52
Full-Text Articles in Physical Sciences and Mathematics
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 …
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 …
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.
Use Of Ponds And Lakes By Resident Canada Geese, Phillip D. West
Use Of Ponds And Lakes By Resident Canada Geese, Phillip D. West
Dissertations, Theses, and Masters Projects
No abstract provided.
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 …
Investigations Into The Etiology Of Ulcerative Lesions In Atlantic Menhaden, Brevoortia Tyrannus, Raemarie Ann Johnson
Investigations Into The Etiology Of Ulcerative Lesions In Atlantic Menhaden, Brevoortia Tyrannus, Raemarie Ann Johnson
Dissertations, Theses, and Masters Projects
No abstract provided.
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.
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.
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 …
Distribution, Abundance, And Home Range Of The Whip-Poor-Will (Caprimulgus Vociferus) In A Managed Forest Landscape, Michael Daniel Wilson
Distribution, Abundance, And Home Range Of The Whip-Poor-Will (Caprimulgus Vociferus) In A Managed Forest Landscape, Michael Daniel Wilson
Dissertations, Theses, and Masters Projects
No abstract provided.
Avian Communities Of Created And Natural Wetlands: Saltmarshes Of Southeast Virginia, David William Desrochers
Avian Communities Of Created And Natural Wetlands: Saltmarshes Of Southeast Virginia, David William Desrochers
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.
Measurement Of The Neutron (Helium-3) Spin Structure Functions At Low 4-Momentum: A Connection Between The Bjorken And Gerasimov-Drell-Hearn Sum Rule, Pibero Kisa Djawotho
Measurement Of The Neutron (Helium-3) Spin Structure Functions At Low 4-Momentum: A Connection Between The Bjorken And Gerasimov-Drell-Hearn Sum Rule, Pibero Kisa Djawotho
Dissertations, Theses, and Masters Projects
This dissertation presents results of experiment E94-010 performed at Jefferson Laboratory (simply known as JLab) in Hall A.;The experiment aimed to measure the low Q2 evolution of the Gerasimov-DrellHearn (GDH) integral from Q 2 = 0.1 to 0.9 GeV2. The GDH sum rule at the real photon point provides an important test of Quantum Chromodynamics (QCD). The low Q2 evolution of the GDH integral contests various resonance models, Chiral Perturbation Theory (chiPT) and lattice QCD calculations, but more importantly, it helps us understand the transition between partonic and hadronic degrees of freedom. at high Q2, beyond 1 GeV2, the difference …
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 …
Multinuclear Nmr Studies Of Relaxor Ferroelectrics, Donghua Zhou
Multinuclear Nmr Studies Of Relaxor Ferroelectrics, Donghua Zhou
Dissertations, Theses, and Masters Projects
Multinuclear NMR of 93Nb, 45Sc, and 207Pb has been carried out to study the structure, disorder, and dynamics of a series of important solid solutions: perovskite relaxor ferroelectric materials (1-x) Pb(Mg1/3Nb 2/3)O3-x Pb(Sc1/2Nb1/2)O 3 (PMN-PSN).;93Nb NMR investigations of the local structure and cation order/disorder are presented as a function of PSN concentration, x. The superb fidelity and accuracy of 3QMAS allows us to make clear and consistent assignments of spectral intensities to the 28 possible nearest B-site neighbor (nBn) configurations, (NMg, NSc, NNb), where each number ranges from 0 to 6 and their sum is 6. For most of the …
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 …
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 …
The Effect Of An Adsorbate Upon Secondary Emission Properties Of Low -Energy Ion Bombarded Metallic And Semiconductor Substrates, Wendy Sara Vogan
The Effect Of An Adsorbate Upon Secondary Emission Properties Of Low -Energy Ion Bombarded Metallic And Semiconductor Substrates, Wendy Sara Vogan
Dissertations, Theses, and Masters Projects
The absolute probabilities for low energy ion bombardment induced secondary emission of electrons and anions have been measured as a function of adsorbate coverage of the surface. The primary ion beams were incident at less than 500 eV on metallic, semiconducting and insulating surfaces. The adsorbate used was chiefly oxygen, and the coverage range studied was zero to about one monolayer. The presence of an adsorbate was observed to significantly enhance secondary emission of electrons and anions in the case of O - and Na+ impacting metallic (W, Al) and semiconducting (Si) substrates; the effect of the adsorbate was little …
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 …
Transport Analysis In Polymeric Liquids And Films: Investigations In Ionic Mobility Isolation Techniques And Permeability Control, Julia D. Warner
Transport Analysis In Polymeric Liquids And Films: Investigations In Ionic Mobility Isolation Techniques And Permeability Control, Julia D. Warner
Dissertations, Theses, and Masters Projects
An in situ measurement technique that isolates the mobility of charge carriers is described and analyzed. The technique allows significant improvement over conductivity measurements to monitor changes in the physical properties and state of a material as it cures. This is essential in systems where Ni, the number of charge carriers, cannot be assumed constant such as during cure of epoxies, urethanes and polyimides.;Currently, there is an assumption made in the literature that the number of charge carriers present in a curing material is constant when conductivity is used as an in situ measurement technique to monitor changes in mobility. …
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 …
Historical Diet Analysis Of Loggerhead (Caretta Caretta) And Kemp's Ridley (Lepidochelys Kempi) Sea Turtles In Virginia, Erin E. Seney
Historical Diet Analysis Of Loggerhead (Caretta Caretta) And Kemp's Ridley (Lepidochelys Kempi) Sea Turtles In Virginia, Erin E. Seney
Dissertations, Theses, and Masters Projects
The Chesapeake Bay and coastal waters of Virginia, U.S.A. serve as foraging grounds for loggerhead (Caretta caretta) and Kemp’s ridley (Lepidochelys kempi) sea turtles from approximately May to October each year. Both loggerheads and Kemp’s ridleys are known to feed primarily on benthic invertebrates as juveniles and adults, but specific prey preferences vary between geographic regions. The Virginia Institute of Marine Science Sea Turtle Program has collected diet data and gut samples from stranded and incidentally caught sea turtles in Virginia since 1979. Examination of turtles that stranded in Virginia during the late 1970s and early 1980s indicated that loggerheads …
Ecosystem Gas Exchange In Natural And Created Tidal Salt Marshes Of Tidewater, Virginia, Molly Mitchell Roggero
Ecosystem Gas Exchange In Natural And Created Tidal Salt Marshes Of Tidewater, Virginia, Molly Mitchell Roggero
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.
Sublethal Effects Of Sediment Contamination On An Estuarine Amphipod, Bruce W. Vogt
Sublethal Effects Of Sediment Contamination On An Estuarine Amphipod, Bruce W. Vogt
Dissertations, Theses, and Masters Projects
No abstract provided.
Genetic Variation Within And Among The Suminoe Oyster (Crassostrea Ariakensis) Populations And Stocks As Assessed By Molecular Markers, Qian Zhang
Dissertations, Theses, and Masters Projects
No abstract provided.
Bacterial Properties And Dissolved Organic Matter Distributions In The Black Sea, Jessica A. Morgan
Bacterial Properties And Dissolved Organic Matter Distributions In The Black Sea, Jessica A. Morgan
Dissertations, Theses, and Masters Projects
No abstract provided.
Biology Of Mated Triploid Crassostrea Ariakensis In Multiple Environments: Gametogenesis, Sex Ratio, Disease Prevalence, And Reversion, Alan J. Erskine
Biology Of Mated Triploid Crassostrea Ariakensis In Multiple Environments: Gametogenesis, Sex Ratio, Disease Prevalence, And Reversion, Alan J. Erskine
Dissertations, Theses, and Masters Projects
No abstract provided.
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, …
Long Term Permanent Vegetation Plot Studies In The Matoaka Woods, Williamsburg, Virginia : Establishment And Initial Data Analysis Of Plots Established With The North Carolina Vegetation Survey Protocol, Resampling Of Single Circular Plots And A Comparison Of Results From North Carolina Vegetation Survey Protocol And Single Circular Plot Methods, Jacob Robert George Kribel
Dissertations, Theses, and Masters Projects
No abstract provided.