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Articles 1 - 30 of 34
Full-Text Articles in Physical Sciences and Mathematics
Nonlinear Solutions To A Two-Layer Quasi-Geostrophic Model Of The Gulf Stream, Eiichi Oka
Nonlinear Solutions To A Two-Layer Quasi-Geostrophic Model Of The Gulf Stream, Eiichi Oka
OES Theses and Dissertations
The Gulf Stream shows a large meander off Cape Hatteras. This is driven by an energy conversion process known as baroclinic instability and observations suggest that nonlinearity is an important part in this process. In order to understand the fundamental role of nonlinearity in baroclinic instability, an inviscid 2-layer quasi-geostrophic model is studied.
The linear solution is obtained by methods of normal mode and Fourier-Laplace transforms. It is found that the set corresponding to the continuous spectrum is null and the set corresponding to the discrete spectrum is complete.
The nonlinear solution is expanded in terms of the complete set …
Identification And Quantitation Of Volatile Amines In Marine Sediments, Chuen Mei Huang
Identification And Quantitation Of Volatile Amines In Marine Sediments, Chuen Mei Huang
Chemistry & Biochemistry Theses & Dissertations
Pore waters which were taken from sediments of the Chesapeake Bay were analyzed to determine the presence of volatile amines. A purge-and-trap technique was used to concentrate the amines. Then, following derivatization with heptaflourobutyric anhydride, the HFBA-amines were analyzed by gas chromatography with electron capture detection and with mass spectrometric detection. One secondary amine, diethylamine with a concentration of 0.3-0.6 uM, was found in a total of three pore water samples from cores collected on two different dates. A primary amine, sec-butylamine with a concentration of O. 05 AIM, was also found in one of these same samples. Another primary …
Lithofacies Of The Pliocene Yorktown Formation In The Vicinity Of Kingsmill On The James River, Virginia, Michael David Lawless
Lithofacies Of The Pliocene Yorktown Formation In The Vicinity Of Kingsmill On The James River, Virginia, Michael David Lawless
OES Theses and Dissertations
The Yorktown Formation beds which crop out along the James River in southeastern Virginia near Kingsmill and Carter's Grove are lithologically described in order to compare them with the "typical" Yorktown beds upriver in the area of Fort Boykins, Rushmere, and Cobham Wharf. Thirty-four stratigraphic sections are constructed of the bluffs along the river. The Yorktown beds in the area of Kingsmill and Cobham Wharf are divided into ten lithofacies: the silty sand facies (B), the Chesapecten facies (C), the Glycymeris facies (D), the Chama facies (E), the glauconitic biofragmental sand facies (F), the laminated silty clay facies (G), the …
A Geophysical Study Of The Easternmost Piedmont: Brunswick County, Virginia, Mark A. Corbin
A Geophysical Study Of The Easternmost Piedmont: Brunswick County, Virginia, Mark A. Corbin
OES Theses and Dissertations
Gravity and magnetic models indicate that a steeply dipping, mylonitic shear zone recognized by reconnaissance mapping in the easternmost Piedmont of Brunswick County, Virginia is a listric fault. A pronounced 3 to 5 mgal Bouguer anomaly high is associated with the fault zone. A band of N10° trending aeromagnetic anomalies delineate the areal extent of the fault zone. The fault zone flattens eastward over a short distance to a depth of 15 kms where it joins a near horizontal surface that cuts across the region. This surface is herein interpreted to be a decollement. The fault zone of this study …
Mathematical Models Of Prevascular Tumor Growth By Diffusion, Sophia A. Maggelakis
Mathematical Models Of Prevascular Tumor Growth By Diffusion, Sophia A. Maggelakis
Mathematics & Statistics Theses & Dissertations
A study of several complementary mathematical models that describe the early, prevascular stages of solid tumor growth by diffusion under various simplifying assumptions is presented. The advantage of these models is that their degree of complexity is relatively low, which ensures fairly straightforward comparisons with experimental or clinical data (as it becomes available), yet they are mathematically sophisticated enough to capture the main biological phenomena of interest.
The tumor growth and cell proliferation rate are assumed to depend on the local concentrations of nutrients and inhibitory factors. The effects of geometry and spatially non-uniform inhibitor production and non-uniform nutrient consumption …
Mounting Sex Pheromone: A Novel Pheromone Responsible For Mate Recognition In The Ixodidae, Jgc Hamilton
Mounting Sex Pheromone: A Novel Pheromone Responsible For Mate Recognition In The Ixodidae, Jgc Hamilton
Theses and Dissertations in Biomedical Sciences
Cholesterol oleate was demonstrated to be the cuticular contact sex pheromone of Dermacentor variabilis. This pheromone which has been termed the Mounting Sex Pheromone (MSP) was also demonstrated to be present on the surface of D. andersoni, Amblyomma maculatum and A. americanum. This contact sex pheromone enables males excited and attracted by 2,6-dichlorophenol to identify the female as a potential mating partner. The MSP is the second in the series of three sex pheromones guiding the hierarchy of behavioral responses which constitute tick courtship behavior. Tests with D. variabilis and D. andersoni showed that this pheromone …
Nuclear Fragmentation Energy And Momentum Transfer Distributions In Relativistic Heavy-Ion Collisions, Ferdous Khan
Nuclear Fragmentation Energy And Momentum Transfer Distributions In Relativistic Heavy-Ion Collisions, Ferdous Khan
Physics Theses & Dissertations
An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.
Software Reliability Models, Syed Afzal Hossain
Software Reliability Models, Syed Afzal Hossain
Mathematics & Statistics Theses & Dissertations
The problem considered here is the building of Non-homogeneous Poisson Process (NHPP) model. Currently existing popular NHPP process models like Goel-Okumoto (G-O) and Yamada et al models suffer from the drawback that the probability density function of the inter-failure times is an improper density function. This is because the event no failure in (0, oo] is allowed in these models. In real life situations we cannot draw sample(s) from such a population and also none of the moments of inter-failure times exist. Therefore, these models are unsuitable for modelling real software error data. On the other hand if the density …
The Remipedia (Crustacea): A Study Of Their Reproduction And Ecology, Jill Yager
The Remipedia (Crustacea): A Study Of Their Reproduction And Ecology, Jill Yager
Biological Sciences Theses & Dissertations
Remipedes are an unusual group of troglobitic crustaceans that live exclusively in anchialine caves. Since their discovery in 1979, nine species have been described, seven of which are found in caves in the West Indies, one from the Yucatan peninsula of Mexico and one from the Canary Islands. Most of what is known about these animals has come mainly from taxonomic descriptions. Little has been published about their reproductive biology or ecology. The objectives of this dissertation were to investigate the reproductive biology and ecology of the remipedes inhabiting Sagittarius Cave on Grand Bahama Island, Bahamas.
Sagittarius Cave was chosen …
Best Approximation With Geometric Constraints, Yuesheng Xu
Best Approximation With Geometric Constraints, Yuesheng Xu
Mathematics & Statistics Theses & Dissertations
This is a study of best approximation with certain geometric constraints. Two major problem areas are considered: best Lp approximation to a function in Lp (0,1) by convex functions, (m, n)-convex functions, (m, n)-convex functions and (m, n)-convex splines, for 1 < p < ∞ , and best uniform approximation to a continuous function by convex functions, quasi-convex functions and piecewise monotone functions.
Picoplankton/Phytoplankton Dynamics In Hampton Roads, Virginia, Leslie E. Dorworth
Picoplankton/Phytoplankton Dynamics In Hampton Roads, Virginia, Leslie E. Dorworth
OES Theses and Dissertations
The biomass distribution of the three main size components of the phytoplankton (net, nano, and picoplankton) was examined in the lower Chesapeake Bay. Work was done at two stations during the spring and neap tidal cycles when freshwater flow into the bay was at its seasonal minimum and maximum. Emphasis was placed on how the picoplankton ( < 2.0 μm, > 0.2 μm) reacted during the sampling period.
Picoplankton made up approximately 13% of the total biomass, during the observed time period, at the more oceanic station. The picoplankton fraction contributed up to 16% of the total biomass at the estuarine station. From this …
The Geomorphology And Surficial Geology Of The West Flank Of The Blue Ridge, Sherando Area, Virginia, Derek Weston Ryter
The Geomorphology And Surficial Geology Of The West Flank Of The Blue Ridge, Sherando Area, Virginia, Derek Weston Ryter
OES Theses and Dissertations
The west flank of the Blue Ridge near Sherando, Virginia (Augusta County) consists of many landforms including talus slopes, bedrock cliffs, boulder streams, colluvial slopes, residual knobs, and debris fans. The purpose of this study is to describe the geomorphic history of the area by understanding the spatial and temporal relationships between landforms on the hillslopes.
Boulder streams (maximum 30 m wide, 400 m long, 6.1 m thick) exhibit a gently dipping imbricated fabric and basal shear stresses of 0.1 to 0.4 bars.
Debris fans in Group L (lower) and Group U (upper) are distinguished by topographic position, degree of …
On The Unique Tree Representation Of Graphs, Beverly Jamison
On The Unique Tree Representation Of Graphs, Beverly Jamison
Computer Science Theses & Dissertations
This dissertation investigates classes of graphs which admit tree representations unique up to isomorphism. The definitions of these classes are based on local properties of P4's, A template structure theorem is given which illustrates the nature of the local properties. The template theorem is instantiated for three different classes of graphs. Properties specific to each of the classes are used to produce a tree representation which can be used for graph computations, such as efficient resolution of graph isomorphism. Linear time algorithms for the recognition of three classes of graphs and for the construction of their tree representations …
Detection Of Outliers And Influential Observations In Regression Models, Anwar M. Hossain
Detection Of Outliers And Influential Observations In Regression Models, Anwar M. Hossain
Mathematics & Statistics Theses & Dissertations
Observations arising from a linear regression model, lead one to believe that a particular observation or a set of observations are aberrant from the rest of the data. These may arise in several ways: for example, from incorrect or faulty measurements or by gross errors in either response or explanatory variables. Sometimes the model may inadequately describe the systematic structure of the data, or the data may be better analyzed in another scale. When diagnostics indicate the presence of anomalous data, then either these data are indeed unusual and hence helpful, or contaminated and, therefore, in need of modifications or …
The Temporal And Spatial Distribution Of Blue Crab Larvae On The Mid-Atlantic Bight Adjacent To The Chesapeake Bay, 1982-1983, Lyle Michael Varnell
The Temporal And Spatial Distribution Of Blue Crab Larvae On The Mid-Atlantic Bight Adjacent To The Chesapeake Bay, 1982-1983, Lyle Michael Varnell
OES Theses and Dissertations
Recruitment processes are important information for the management of commercially and recreationally exploited marine species. Recruitment processes of the Chesapeake Bay's most important commercial and recreational species, the blue crab, are unknown, due in part to the lack of knowledge of the processes directly preceeding recruitment.
The present study was undertaken to investigate and explain the movement and developmental patterns of blue crab larvae while offshore. Interannual and intraseasonal variations of these patterns were also examined.
Sampling occurred from May to November during 1982 and 1983. Larvae were collected at three depths (neuston layer (upper 10 cm), one meter and …
Simultaneous Determination Of 3-Methoxy-4-Hydroxyphenyl-Glycol, Homovanillic Acid, And 5-Hydroxyindoleacetic Acid In Plasma By High Performance Liquid Chromatography, Yung-Te Tseng
Chemistry & Biochemistry Theses & Dissertations
A rapid, reliable, and sensitive method for simultaneous determination of 3-methoxy-4-hydroxyphenylglycol (MHPG), Homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5- HIAA) in plasma is described. The method is based on high performance liquid chromatography with electrochemical detection. Samples were filtered with Amicon Centrifree micropartition systems and extracted with organic solvent before chromatography. Chromatographic separation of sample components was achieved isocratically in a C18 reverse-phase column. Quantitation was performed by measuring the peak height ratios of the sample components to an internal standard. Analytical recoveries ranged from 50.78 (SD 4.2%) to 67.94 (SD 3.28). Within-run coefficient of variations (CVs) ranged from 3.78 …
Population Variation In The Mitochondrial-Dna Of Two Marine Organisms: The Hard Shell Clam Mercenaria Spp. And The Killifish, Fundulus Heteroclitus, Bonnie Lynn Brown
Population Variation In The Mitochondrial-Dna Of Two Marine Organisms: The Hard Shell Clam Mercenaria Spp. And The Killifish, Fundulus Heteroclitus, Bonnie Lynn Brown
OES Theses and Dissertations
The two major topics are covered in this dissertation: the integration of molecular genetic tools with applied aquacultural research and short-term evolutionary dynamics. The first study investigated the extent of geographic differentiation of native clam stocks along the U.S. east and Gulf coasts. Clam mitochondrial DNA (mtDNA) demonstrated size polymorphism (16.5-19.0 kb) and restriction site heteroplasmy. Size heteroplasmic individuals occurred at a frequencies of 0-89% in clam populations. Restriction site heteroplasmy occurred in 12% of the 317 individuals assayed. Results of the study indicated that although harbouring a wealth of genetic variation, clams from northern regions were similar and lacked …
A Classification Approach For Automated Reasoning Systems--A Case Study In Graph Theory, Rong Lin
A Classification Approach For Automated Reasoning Systems--A Case Study In Graph Theory, Rong Lin
Computer Science Theses & Dissertations
Reasoning systems which create classifications of structured objects face the problem of how object descriptions can be used to reflect their components as well as relations among these components. Current reasoning systems on graph theory do not adequately provide models to discover complex relations among mathematical concepts (eg: relations involving subgraphs) mainly due to the inability to solve this problem. This thesis presents an approach to construct a knowledge-based system, GC (Graph Classification), which overcomes this difficulty in performing automated reasoning in graph theory. We describe graph concepts based on an attribute called Linear Recursive Constructivity (LRC). LRC defines classes …
Optimal Row-Column Designs For Correlated Errors And Nested Row-Column Designs For Uncorrelated Errors, Nizam Uddin
Optimal Row-Column Designs For Correlated Errors And Nested Row-Column Designs For Uncorrelated Errors, Nizam Uddin
Mathematics & Statistics Theses & Dissertations
In this dissertation the design problems are considered in the row-column setting for second order autonormal errors when the treatment effects are estimated by generalized least squares, and in the nested row-column setting for uncorrelated errors when the treatment effects are estimated by ordinary least squares. In the former case, universal optimality conditions are derived separately for designs in the plane and on the torus using more general linear models than those considered elsewhere in the literature. Examples of universally optimum planar designs are given, and a method is developed for the construction of optimum and near optimum designs, that …
Performance Modeling And Enhancement For The Atamm Data Flow Architecture, Sukhamoy Som
Performance Modeling And Enhancement For The Atamm Data Flow Architecture, Sukhamoy Som
Electrical & Computer Engineering Theses & Dissertations
Algorithm To Architecture Mapping Model (ATAMM) is a new marked graph model from which the rules for data and control flow in a homogeneous, multicomputer, data flow architecture may be defined. This research is concerned with performance modeling and performance enhancement for periodic execution of large-grain, decision-free algorithms in such an ATAMM defined architecture. Performance measures and bounds are established. Algorithm transformation techniques are identified for performance enhancement and reduction of computing element requirements. Operating strategies are developed for optimum time performance and for sub-optimum time performance under limited availability of computing elements. An ATAMM simulator is used to test …
The Strong Perfect Graph Conjecture For Pan-Free Graphs, Stephan Olariu
The Strong Perfect Graph Conjecture For Pan-Free Graphs, Stephan Olariu
Computer Science Faculty Publications
A graph G is perfect if for every induced subgraph F of G, the chromatic number χ(F) equals the largest number ω(F) of pairwise adjacent vertices in F. Berge's famous Strong Perfect Graph Conjecture asserts that a graph G is perfect if and only if neither G nor its complement G contains an odd chordless cycle of length at least five. Its resolution has eluded researchers for more than twenty years. We prove that the conjecture is true for a class of graphs which strictly contains the claw-free graphs.
Corrigendum, John A. Adam
Corrigendum, John A. Adam
Mathematics & Statistics Faculty Publications
No abstract provided.
A New Conjecture About Minimal Imperfect Graphs, H. Meyniel, Stephan Olariu
A New Conjecture About Minimal Imperfect Graphs, H. Meyniel, Stephan Olariu
Computer Science Faculty Publications
H. Meyniel proved that in every minimal imperfect graph, every pair of vertices is joined by a chordless path containing an odd number of edges. We conjectured that in every minimal imperfect graph, every pair of vertices is joined by a path containing an even number of edges. We give an equivalent version of this new conjecture.
Weak Bipolarizable Graphs, Stephan Olariu
Weak Bipolarizable Graphs, Stephan Olariu
Computer Science Faculty Publications
We characterize a new class of perfectly orderable graphs and give a polynomial-time recognition algorithm, together with linear-time optimization algorithms for this class of graphs.
Fixed Point Theorems For Compatible Multi-Valued And Single-Valued Mappings, Hideaki Kaneko, Salvatore Sessa
Fixed Point Theorems For Compatible Multi-Valued And Single-Valued Mappings, Hideaki Kaneko, Salvatore Sessa
Mathematics & Statistics Faculty Publications
The notion of compatibility for point-to-point mappings recently defined by Jungck is generalized to include multi-valued mappings. This idea is used to establish a fixed point theorem for a generalized contractive multi-valued mapping and a single-valued mapping.
A Nonlinear Eigenvalue Problem In Astrophysical Magnetohydrodynamics: Some Properties Of The Spectrum, John A. Adam
A Nonlinear Eigenvalue Problem In Astrophysical Magnetohydrodynamics: Some Properties Of The Spectrum, John A. Adam
Mathematics & Statistics Faculty Publications
The equations of ideal magnetohydrodynamics (MHD) with an external gravitational potential—a ‘‘magnetoatmosphere’’—are examined in detail as a singular nonlinear eigenvalue problem. Properties of the spectrum are discussed with specific emphasis on two systems relevant to solar magnetohydrodynamics. In the absence of a gravitational potential, the system reduces to that of importance in MHD and plasma physics, albeit in a different geometry. This further reduces to a form isomorphic to that derived in the study of plasma oscillations in a cold plasma, Alfvén wave propagation in an inhomogeneous medium, and MHD waves in a sheet pinch. In cylindrical geometry, the relevant …
Hydrographic Variability Of Southeastern United States Shelf And Slope Waters During The Genesis Of Atlantic Lows Experiment: Winter 1986, Larry P. Atkinson, Eiichi Oka, Sunny Y. Wu, Thomas J. Berger, Jackson O. Blanton, Thomas N. Lee
Hydrographic Variability Of Southeastern United States Shelf And Slope Waters During The Genesis Of Atlantic Lows Experiment: Winter 1986, Larry P. Atkinson, Eiichi Oka, Sunny Y. Wu, Thomas J. Berger, Jackson O. Blanton, Thomas N. Lee
CCPO Publications
Continental shelf waters are particularly responsive to winter storm events mainly because of their shallow depths. Those of the southeastern United States (the South Atlantic Bight (SAB)) are especially responsive because they are broad and shallow. Also, the Gulf Stream serves as a continual source of warm water at the outer boundary. Thus the SAB receives strong meteorological (wind stress and heat loss) and oceanographic (advective) forcing. During the Genesis of Atlantic Lows Experiment (GALE) the response of shelf waters to winter storm events and Gulf Stream forcing was observed. The mean conditions showed a mixed water column with areas …
Permanganate Colorimetric Rapid Method For Chemical Oxygen Demand In Seawater, Myung Zoon Czae, Taekee Hong, Myung Hoon Kim
Permanganate Colorimetric Rapid Method For Chemical Oxygen Demand In Seawater, Myung Zoon Czae, Taekee Hong, Myung Hoon Kim
Chemistry & Biochemistry Faculty Publications
No abstract provided.
Nanosecond Optical Quenching Of Photoconductivity In A Bulk Gaas Switch, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, S. T. Ko
Nanosecond Optical Quenching Of Photoconductivity In A Bulk Gaas Switch, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, S. T. Ko
Electrical & Computer Engineering Faculty Publications
Persistent photoconductivity in copper-compensated, silicon-doped semi-insulating gallium arsenide with a time constant as large as 30 µs has been excited by sub-band-gap laser radiation of photon energy greater than 1 eV. This photoconductivity has been quenched on a nanosecond time scale by laser radiation of photon energy less than 1 eV. The proven ability to turn the switch conductance on and off on command, and to scale the switch to high power could make this semiconductor material the basis of an optically controlled pulsed-power closing and opening switch.
Gaas Photoconductive Closing Switches With High Dark Resistance And Microsecond Conductivity Decay, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, R. Germer, G. M. Loubriel, F. J. Zutavern
Gaas Photoconductive Closing Switches With High Dark Resistance And Microsecond Conductivity Decay, M. S. Mazzola, K. H. Schoenbach, V. K. Lakdawala, R. Germer, G. M. Loubriel, F. J. Zutavern
Electrical & Computer Engineering Faculty Publications
Silicon-doped n-type gallium arsenide crystals, compensated with diffused copper, were studied with respect to their application as photoconductive, high-power closing switches. The attractive features of GaAs:Cu switches are their high dark resistivity, their efficient activation with Nd:YAG laser radiation, and their microsecond conductivity decay time constant. In the authors' experiment, electric fields are high as 19 kV/cm were switched, and current densities of up to 10 kA/cm2 were conducted through a closely compensated crystal. At field strengths greater than approximately 10 kV/cm, a voltage `lock-on' effect was observed.