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Articles 31 - 52 of 52
Full-Text Articles in Physical Sciences and Mathematics
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 …
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.
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.
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.
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.
Automated Fish Species Classification Using Artificial Neural Networks And Autonomous Underwater Vehicles, Daniel Foster Doolittle
Automated Fish Species Classification Using Artificial Neural Networks And Autonomous Underwater Vehicles, Daniel Foster Doolittle
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 …
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 …
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 …
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. …
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.
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.
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 …
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.
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.
Net Surface Flux Budget Over Tropical Oceans Estimated From The Tropical Rainfall Measuring Mission (Trmm), Tai-Fang Fan
Net Surface Flux Budget Over Tropical Oceans Estimated From The Tropical Rainfall Measuring Mission (Trmm), Tai-Fang Fan
Dissertations, Theses, and Masters Projects
No abstract provided.