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Articles 1171 - 1200 of 1876
Full-Text Articles in Physical Sciences and Mathematics
Metallization Of Polyimide Films To Enhance Dimensional Stability And To Achieve Reflective And Conductive Surfaces, David Scott Thompson
Metallization Of Polyimide Films To Enhance Dimensional Stability And To Achieve Reflective And Conductive Surfaces, David Scott Thompson
Dissertations, Theses, and Masters Projects
No abstract provided.
Characterization Of Nylon-11 Degradation, Leslie Christian Mccullough
Characterization Of Nylon-11 Degradation, Leslie Christian Mccullough
Dissertations, Theses, and Masters Projects
No abstract provided.
Characterization Of Pr500 For Use In Resin Transfer Molding, Rhonda Michelle Barksdale
Characterization Of Pr500 For Use In Resin Transfer Molding, Rhonda Michelle Barksdale
Dissertations, Theses, and Masters Projects
No abstract provided.
A Study Of The Histozoic Oyster Parasite, Perkinsus Marinus: I. Disease Processes In American Oysters (Crassostrea Virginica). Ii. Biochemistry Of Perkinsus Marinus, Aswani K. Volety
Dissertations, Theses, and Masters Projects
Numerous studies have investigated the disease processes of Perkinsus marinus in the oyster, Crassostrea virginica. However, the transmission dynamics and factors affecting P. marinus infection are still unclear. The objectives of this study were to investigate: (1) the principal and most effective lifestage of P. marinus, (2) the synergistic effects of temperature, salinity and P. marinus dose on disease prevalence, (3) suppression of host reactive oxygen intermediates by P. marinus, (4) the localization of acid phosphatase in the parasite, (5) the effects of temperature and salinity on acid phosphatase secretion, and (6) the P. marinus lipid and fatty acid composition. …
Deuteron Nuclear Magnetic Resonance Studies Of Molecular Motion In Solids, Tak Yan Tse
Deuteron Nuclear Magnetic Resonance Studies Of Molecular Motion In Solids, Tak Yan Tse
Dissertations, Theses, and Masters Projects
$\sp2$H-NMR is a powerful spectroscopic technique for investigating dynamics in solids. to extend the range of motional rates that can be quantitatively investigated, a new approach for measuring the quadrupolar spin-lattice relaxation time $T\sb{1Q}$ was developed. This uses a Broadband Jeener-Broekaert (BBJB) sequence with echo-detection, which avoids the frequency-discriminated excitation profile and spectral baseline distortion intrinsic to the conventional Jeener-Broekaert (JB) experiment. By combining the BBJB experiment with an Inversion-Recovery sequence with Quadrupole-Echo detection (IRQE), two independent longitudinal relaxation times, $T\sb{1Q}$ and $T\sb{1Z}$, can be measured. Spectral densities of motion $J\sb1(\omega\sb{o}$) and $J\sb2(2\omega\sb{o}$) are extracted from these relaxation times. The …
Comparative Toxicity Of Creosote And Creosote Contaminated Sediments, Padma T. Venkatraman
Comparative Toxicity Of Creosote And Creosote Contaminated Sediments, Padma T. Venkatraman
Dissertations, Theses, and Masters Projects
No abstract provided.
Mechanisms Of Larval Spot Transport And Recruitment To The Chesapeake Bay, Deborah A. Bodolus
Mechanisms Of Larval Spot Transport And Recruitment To The Chesapeake Bay, Deborah A. Bodolus
Dissertations, Theses, and Masters Projects
The spot (Leiostomus xanthurus) is an important commercial and recreational species in Virginia. Recruitment of juveniles to the Bay is characterized by large interannual fluctuations, that can be explained by the sequence and direction of wind during various phases of the early life history. An environmentally-modified Ricker stock-recruitment curve was developed incorporating the southeasterly winds in November-December, the southerly winds in January-March, and the westerly winds in April-May. This model explained 81% of the variation and closely paralleled the VIMS Juvenile Spot Index. Spot from the Chesapeake Bay migrate south in fall to spawn near or south of Cape Hatteras. …
Alternative Management Programs Within The Atlantic Sea Scallop Placopecten Magellanicus Fishery: Property Rights, Transferable Quotas And Fishing Effort, Niels E. Moore
Dissertations, Theses, and Masters Projects
No abstract provided.
Directional Wave Spectra Using An Acoustic Doppler Current Profiler, William T. Stockhausen
Directional Wave Spectra Using An Acoustic Doppler Current Profiler, William T. Stockhausen
Dissertations, Theses, and Masters Projects
No abstract provided.
General Methods For Analyzing Machine Learning Sample Complexity, Christoph Cornelius Michael
General Methods For Analyzing Machine Learning Sample Complexity, Christoph Cornelius Michael
Dissertations, Theses, and Masters Projects
During the past decade, there has been a resurgence of interest in applying mathematical methods to problems in artificial intelligence. Much work has been done in the field of machine learning, but it is not always clear how the results of this research should be applied to practical problems. Our aim is to help bridge the gap between theory and practice by addressing the question: "If we are given a machine learning algorithm, how should we go about formally analyzing it?" as opposed to the usual question: "how do we write a learning algorithm we can analyze?".;We will consider algorithms …
Great Blue Herons And River Otters: The Changing Perceptions Of All Things Wild In The Seventeenth And Eighteenth-Century Chesapeake, Elise Helene Manning-Sterling
Great Blue Herons And River Otters: The Changing Perceptions Of All Things Wild In The Seventeenth And Eighteenth-Century Chesapeake, Elise Helene Manning-Sterling
Dissertations, Theses, and Masters Projects
No abstract provided.
Global Phylogeography Of Yellowfin Tuna, Thunnus Albacares, And Mackerels Of The Genus Scomber, Daniel R. Scoles
Global Phylogeography Of Yellowfin Tuna, Thunnus Albacares, And Mackerels Of The Genus Scomber, Daniel R. Scoles
Dissertations, Theses, and Masters Projects
Intraspecific genetic relationships within yellowfin tuna, Thunnus albacares, and three mackerels of the genus Scomber were studied by restriction fragment length polymorphism (RFLP) analysis of mitochondrial DNA (mtDNA). The comparison of these scombrids, with different larval distributions, adult distributions, and vagilities, served to investigate the hypothesis that population structure in marine fishes results from geographic and physical oceanographic processes that limit dispersal of early life history stages. Samples of 20 yellowfin tuna were examined from each of five Pacific locations and one Atlantic location. MtDNA analysis with 12 informative restriction endonucleases demonstrated considerable genetic variation, as evidenced by overall nucleon …
An Investigation Of The Late Quaternary Morphology Of Mobjack Bay, Va And Application Of A Facies Model, Donna Angela Milligan
An Investigation Of The Late Quaternary Morphology Of Mobjack Bay, Va And Application Of A Facies Model, Donna Angela Milligan
Dissertations, Theses, and Masters Projects
No abstract provided.
The Synthesis Of 5-Benzoyl-1,3-Benzendediacids For The Double-Capping Of Beta-Cyclodextrin, Daniel Macdougall Williams
The Synthesis Of 5-Benzoyl-1,3-Benzendediacids For The Double-Capping Of Beta-Cyclodextrin, Daniel Macdougall Williams
Dissertations, Theses, and Masters Projects
No abstract provided.
Perspectives On Nature: A Comparison Of The Views Of Thomas Jefferson And Henry David Thoreau, Stephanie Brewer Foley
Perspectives On Nature: A Comparison Of The Views Of Thomas Jefferson And Henry David Thoreau, Stephanie Brewer Foley
Dissertations, Theses, and Masters Projects
No abstract provided.
Inverse Estimation Of Horizontal Pressure Gradients And Vertical Eddy Viscosity Profiles In Shallow Waters, Bohyun Bang
Inverse Estimation Of Horizontal Pressure Gradients And Vertical Eddy Viscosity Profiles In Shallow Waters, Bohyun Bang
Dissertations, Theses, and Masters Projects
A least-squares inverse method was devised to estimate horizontal pressure gradients and vertical eddy-viscosity profiles simultaneously, from current profiles. The method was designed mostly for observations of deterministic or near-deterministic wave currents. Tidal-current observations were chosen for the present study. The inverse system was constructed from a linearized momentum equation. The viscosity was modeled with a time-constant and harmonic function in time, but without its vertical structure predefined. The least-squares problem was solved with the singular value decomposition, by taking current harmonic profiles as input. at first, the method was tested with current profiles simulated by a numerical model employing …
The Effects Of Contaminated Sediment On The Epidermal Goblet Cells Of The Mummichog, Fundulus Heteroclitus, Laurent C. Mézin
The Effects Of Contaminated Sediment On The Epidermal Goblet Cells Of The Mummichog, Fundulus Heteroclitus, Laurent C. Mézin
Dissertations, Theses, and Masters Projects
Secretion of mucus by epidermal goblet cells is an important first line of defense for teleosts. It protects them against many of the biological, physical and chemical insults they encounter in their environment. This project monitored changes in hemoglobin concentration in epidermal mucus and in the density, diameter and mucus quality of epidermal goblet cells in the mummichog, Fundulus heteroclitus, following exposure to creosote-contaminated sediment. Male fish (200) were exposed for 13 days in flowthough aquaria to either an uncontaminated reference sediment or contaminated sediment containing 30% Elizabeth River sediment. Fish were sampled on Days 0, 3, 7 and 13. …
Toxicity Resistance In Mummichog (Fundulus Heteroclitus) From A Chemically Contaminated Environment, Cynthia A. H. Williams
Toxicity Resistance In Mummichog (Fundulus Heteroclitus) From A Chemically Contaminated Environment, Cynthia A. H. Williams
Dissertations, Theses, and Masters Projects
No abstract provided.
Physical And Mechanical Behavior Of Amorphous Poly(Arylene Ether-Co-Imidazole)S And Poly(Arylene Ether-Co-Imidazole) Modified Epoxies, Patricia D. Roberts-Mcdaniel
Physical And Mechanical Behavior Of Amorphous Poly(Arylene Ether-Co-Imidazole)S And Poly(Arylene Ether-Co-Imidazole) Modified Epoxies, Patricia D. Roberts-Mcdaniel
Dissertations, Theses, and Masters Projects
Due to the high crosslink density of cured epoxy resins they generally lack damage tolerance. A significant amount of research has been expended to improve the toughness of epoxies. Research into the area of thermoplastic epoxy modifiers has begun to overcome some of the limitations of early methods of epoxy toughening (i.e. lower modulus and thermal stability).;This study examines the physical and mechanical properties of random poly(arylene ether-co-imidazole) (PAE-co-Is) and the characterization of epoxies modified with poly(arylene ether-co-imidazole)s.;Poly(arylene ether-co-imidazole)s exhibited the highest solubility in N,N,N{dollar}\rm\sp\prime,N\sp\prime,{dollar}-tetraglycidyl- 4,4{dollar}\sp\prime{dollar} diaminodiphenyl methane (TGMDA) based resins. The high molecular weight polymers caused significant decreases in …
Compilation Techniques For Irregular Problems On Parallel Machines, Subhendu Das
Compilation Techniques For Irregular Problems On Parallel Machines, Subhendu Das
Dissertations, Theses, and Masters Projects
Massively parallel computers have ushered in the era of teraflop computing. Even though large and powerful machines are being built, they are used by only a fraction of the computing community. The fundamental reason for this situation is that parallel machines are difficult to program. Development of compilers that automatically parallelize programs will greatly increase the use of these machines.;A large class of scientific problems can be categorized as irregular computations. In this class of computation, the data access patterns are known only at runtime, creating significant difficulties for a parallelizing compiler to generate efficient parallel codes. Some compilers with …
Muon Transfer From Muonic Deuterium To Carbon, David William Viel
Muon Transfer From Muonic Deuterium To Carbon, David William Viel
Dissertations, Theses, and Masters Projects
Negative muons were brought to rest in a gas mixture of 30 torr CH$\sb4$ and 570 torr D$\sb2$, using the cyclotron trap at PSI. The muons formed muonic deuterium atoms which diffused through the mixture and transferred their muons to the carbon of the CH$\sb4$ molecules. A planar germanium detector and a silicon detector were used to observe x-rays from the initial muon cascade in the deuterium, and from subsequent cascade in the muonic carbon after transfer. A transfer rate of (4.5 $\pm$ 1.8) $\times$ 10$\sp{10}$/sec was found which agrees well with a previous result measured at 50 bar of …
Collisions Of Atomic Hydrogen With Oxygen, Sulfur, Sodium And Halogen Anions At Low Energies, James Anthony Fedchak
Collisions Of Atomic Hydrogen With Oxygen, Sulfur, Sodium And Halogen Anions At Low Energies, James Anthony Fedchak
Dissertations, Theses, and Masters Projects
Total electron detachment and charge transfer cross sections, $\sigma\sb{\rm e}$(E) and $\sigma\sb{\rm ct}$(E), have been measured for collisions of the negative ions O$\sp{-}$, S$\sp{-}$, F$\sp{-}$, Cl$\sp{-}$, Br$\sp{-}$, I$\sp{-}$, Na$\sp{-}$, and K$\sp{-}$ with atomic hydrogen for laboratory energies ranging from 2 to 500 eV. For the systems F$\sp{-}$, Cl$\sp{-}$, Br$\sp{-}$, O$\sp{-}$ and S$\sp{-}$ + H, $\sigma\sb{\rm e}$(E) displays no barrier for associative detachment; the results are found to be adequately described by simple curve-crossing models based upon available intermolecular potentials, or by classical orbiting models which assume that the anion interacts with the H atom via an attractive potential of the …
Photoabsorption Spectra Of Hydrogen And Alkali Atoms In Electric Fields, Jing Gao
Photoabsorption Spectra Of Hydrogen And Alkali Atoms In Electric Fields, Jing Gao
Dissertations, Theses, and Masters Projects
A systematic study of the photoabsorption spectra of highly excited hydrogen and alkali atoms in electric fields is presented, based on the semiclassical closed-orbit theory. In most respects, hydrogen and alkali atoms behave similarly, because the excited alkali atoms have a single electron outside of a small ionic core, and the core only produces small shifts of energy levels and small phase shifts of scattered wave functions.;For hydrogen, the classical motion of the excited electron is regular and closed orbits can be enumerated. Above the zero-field ionization threshold, the system is rather simple. There is only one closed orbit, called …
A Relativistic Model Of Pion Nucleon Scattering And Pion Photoproduction On A Single Nucleon, Yohanes Surya
A Relativistic Model Of Pion Nucleon Scattering And Pion Photoproduction On A Single Nucleon, Yohanes Surya
Dissertations, Theses, and Masters Projects
Pion nucleon scattering is described by a manifestly covariant wave equation in which the pion is restricted to its mass-shell. The kernel of the equation includes nucleon (N), Roper (N*), delta ({dollar}\Delta{dollar}) and {dollar}D\sb{lcub}13{rcub}{dollar} poles, with their corresponding crossed pole terms approximated by contact interactions, and contact {dollar}\sigma{dollar}- and {dollar}\rho{dollar}-like exchange terms. The {dollar}\pi NN{dollar} vertex is treated as a mixture of {dollar}\gamma\sp5{dollar} and {dollar}\gamma\sp\mu\gamma\sp5{dollar} coupling, with a mixing parameter {dollar}\lambda{dollar} chosen so that the dressed nucleon pole will be unshifted by the interaction. Chiral symmetry is maintained at threshold. The resonance contributions are fully unitarized by the equation, with …
Predation On Juvenile Blue Crabs, Callinectes Sapidus Rathbun, In Lower Chesapeake Bay: Patterns, Predators, And Potential Impacts, Kirt E. Moody
Predation On Juvenile Blue Crabs, Callinectes Sapidus Rathbun, In Lower Chesapeake Bay: Patterns, Predators, And Potential Impacts, Kirt E. Moody
Dissertations, Theses, and Masters Projects
Various investigations of the population dynamics of blue crabs in Chesapeake Bay indicate that predator-induced mortality in the juvenile phase may determine year-class strength. In a tethering study, which spanned three seasons in shallow-water habitats of the lower York River, daily mortality rates of juvenile crabs were measured across three variables: crab size (30-70 mm carapace width), habitat type (seagrass, mud, and sand), and month (May-November). Vulnerability to predation was consistently lower for larger crabs, approaching a size refuge from predation at approximately 90 mm carapace width. Predation was most intense in unvegetated sand habitats, and significantly lower in seagrass …
Use Of A Landscape-Level Approach To Determine The Habitat Requirements Of The Yellow-Crowned Night-Heron, Nycticorax Violaceus, In The Lower Chesapeake Bay, Ellen L. Bentley
Use Of A Landscape-Level Approach To Determine The Habitat Requirements Of The Yellow-Crowned Night-Heron, Nycticorax Violaceus, In The Lower Chesapeake Bay, Ellen L. Bentley
Dissertations, Theses, and Masters Projects
No abstract provided.
A Gis Spatial Analysis Of The Potential Conflict Between Submerged Aquatic Vegetation Management And The Development Of Shellfish Aquaculture In The Lower Chesapeake Bay, Laura Ann Grignano
A Gis Spatial Analysis Of The Potential Conflict Between Submerged Aquatic Vegetation Management And The Development Of Shellfish Aquaculture In The Lower Chesapeake Bay, Laura Ann Grignano
Dissertations, Theses, and Masters Projects
No abstract provided.
In Vitro And In Vivo Effects Of Chemotherapeutants On The Oyster Parasite, Perkinsus Marinus, Gustavo W. Calvo
In Vitro And In Vivo Effects Of Chemotherapeutants On The Oyster Parasite, Perkinsus Marinus, Gustavo W. Calvo
Dissertations, Theses, and Masters Projects
To investigate the potential of chemotherapeutants to control the oyster pathogen Perkinsus marinus, anticoccidial and antifungal compounds were tested in vitro on infected hemolymph and cultured P. marinus cells and in vivo on infected oysters. In addition, acute toxicity to oysters was determined for six anticoccidials. In vitro experiments with infected hemolymph consisted of 24 h exposure of 0.2 mL hemolymph aliquots to concentrations ranging from 100 mg/L to 0.01 mg/L of amphotericin-B, amprolium, arprinocid, cycloheximide, lasalocid, malachite green, monensin, sulfadimethoxine, and a potentiated sulfadimethoxine, followed by incubation in fluid thioglycollate medium (FTM) to determine prezoosporangia abundance. Lasalocid, malachite green, …
Size-Specific Fecundity Of The Sea Scallop, Placopecten Magellanicus, During One Spawning Period In The Mid-Atlantic Resource Area, Ryan B. Carnegie
Size-Specific Fecundity Of The Sea Scallop, Placopecten Magellanicus, During One Spawning Period In The Mid-Atlantic Resource Area, Ryan B. Carnegie
Dissertations, Theses, and Masters Projects
No abstract provided.
Food, Feeding, And Length-Weight Relationships Of Young-Of-The-Year Striped Bass, Morone Saxatilis And Young-Of-The-Year White Perch, Morone Americana, Paul J. Rudershausen
Food, Feeding, And Length-Weight Relationships Of Young-Of-The-Year Striped Bass, Morone Saxatilis And Young-Of-The-Year White Perch, Morone Americana, Paul J. Rudershausen
Dissertations, Theses, and Masters Projects
No abstract provided.