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Circulation, Vol. 7, No. 2, Center For Coastal Physical Oceanography, Old Dominion University, Bettina Fach

CCPO Circulation

Spring 2000 issue of CCPO Circulation featuring article "Cruising the Southern Ocean" by Bettina Fach

Feeding Habits Of Young-Of-Year Striped Bass, Morone Saxatilis, And White Perch, Morone Americana, In Lower James River, Va, Paul J. Rudershausen, Joseph G. Loesch

Virginia Journal of Science

A total of 188 young-of-year (YOY) striped bass, Morone saxatilis, and 199 YOY white perch, Morone americana, were collected by pushnet, seine and trawl during 24-hour periods from June through August, 1992 in lower James River, Virginia. The purpose was to identify prey and temporal and spatial feeding habits. Copepods were the most numerous prey of both species. Fishes and mysids comprised the largest volumetric percentage of diets of striped bass and white perch, respectively. Using an index of relative importance, leptodorids and copepods were the most important prey of striped bass and white perch, respectively. Both species …

The Fermat Point And The Steiner Problem, J. N. Boyd, P. N. Raychowdhury

Virginia Journal of Science

We revisit the convex coordinates of the Fermat point of a triangle. We have already computed these convex coordinates in a general setting. In this note, we obtain the coordinates in the context of the Steiner problem. Thereafter, we pursue calculations suggested by the problem.

Jeffress Research Grant Awards

Virginia Journal of Science

Announcements of the Jeffress Research Grants that have been awarded in 1999.

Generalized Compton Amplitudes In Quantum Chromodynamics, Ignati Grigentch

Physics Theses & Dissertations

In this dissertation we describe results of our studies of generalized Compton amplitudes. We have calculated the one-loop corrections to the amplitude in the coordinate representation in terms of nonlocal string light-ray operators. We have also developed a consistent approach to the problem of constructing the gauge invariant Compton amplitude and obtained an expression for the explicitly gauge invariant amplitude which includes all the generalized target-mass corrections.

Curvilinear Interface Methodology For Finite-Element Applications, Ollie James Rose

Mechanical & Aerospace Engineering Theses & Dissertations

Recent trends in design and manufacturing suggest a tendency toward multiple centers of specialty which results in a need for improved integration methodology for dissimilar finite element or CFD meshes. Since a typical finite element or CFD analysis requires about 50% of an engineers effort to be devoted to modeling and input, there is a need to advance the state-of-the-art in modeling, methodology. These two trends indicate a need to for the capability to combine independently-modeled configurations in an automated and robust way without the need for global remodeling. One approach to addressing this need is the development of interfacing …

Diffusion Problems In Wound Healing And A Scattering Approach To Immune System Interactions, Julia Suzanne Arnold

Mathematics & Statistics Theses & Dissertations

A theoretical model for the existence of a Critical Size Defect (CSD) in certain animals is the focus of the majority of this dissertation. Adam [1] recently developed a one-dimensional model of this phenomenon, and chapters I–V address the exist the CSD in a two-dimensional model and a three-dimensional model. The two dimensional (or 1-d circular) model is the more appropriate for a study of CSD's. In that model we assume a circular wound of uniform depth and develop a time-independent form of the diffusion equation relevant to the study of the CSD phenomenon. It transpires that the range of …

A Buffered Advection/Dispersion Lake Water Quality Transport Framework For Modeling Lake Gaston Pipeline Intake Water Withdrawal, Lloyd Ashton Gatling

Civil & Environmental Engineering Theses & Dissertations

Water quality response to reservoir water withdrawal is investigated in Pea Hill Arm of Lake Gaston, a non-tidal reservoir tributary, where the point of water withdrawal is in an upstream tributary and influences the direction of tributary flow causing longitudinal velocity null flow conditions to occur. The study also focuses on control of withdrawal rate and timing to optimize both quality of water remaining in the tributary and quantity of water that can be safely withdrawn.

Research was conducted assuming steady state conditions and later under spatial and temporal variability experienced in the reservoir with main lake pool elevation fluctuations …

Precision Measurement Of The Spin Structure Of The Proton And The Deuteron, Frank R. Wesselmann

Physics Theses & Dissertations

Experiment E155 at the Stanford Linear Accelerator Center measured the spin structure functions g1 and g2 of the proton and deuteron using deep inelastic scattering of 50 GeV polarized electrons from dynamically polarized, solid ¹⁵NH₃ and ⁶LiD targets. Three independent spectrometers, covering a large kinematic region, 0.014 < x_Bjorken < 0.9 and 1 < Q² < 40 (GeV /c)^2, detected 200 million events. A fully self-consistent and statistically sound approach to calculating radiative corrections was developed, providing well-defined statistical errors for the E155 data set. Also, a comprehensive fit to the global data set was created which simultaneously …

A Semantic-Based Middleware For Multimedia Collaborative Applications, Agustin Jose Gonzalez

Computer Science Theses & Dissertations

The Internet growth and the performance increase of desktop computers have enabled large-scale distributed multimedia applications. They are expected to grow in demand and services and their traffic volume will dominate. Real-time delivery, scalability, heterogeneity are some requirements of these applications that have motivated a revision of the traditional Internet services, the operating systems structures, and the software systems for supporting application development. This work proposes a Java-based lightweight middleware for the development of large-scale multimedia applications. The middleware offers four services for multimedia applications. First, it provides two scalable lightweight protocols for floor control. One follows a centralized model …

An Object-Oriented Algorithmic Laboratory For Ordering Sparse Matrices, Gary Karl Kumfert

Computer Science Theses & Dissertations

We focus on two known NP-hard problems that have applications in sparse matrix computations: the envelope/wavefront reduction problem and the fill reduction problem. Envelope/wavefront reducing orderings have a wide range of applications including profile and frontal solvers, incomplete factorization preconditioning, graph reordering for cache performance, gene sequencing, and spatial databases. Fill reducing orderings are generally limited to—but an inextricable part of—sparse matrix factorization.

Our major contribution to this field is the design of new and improved heuristics for these NP-hard problems and their efficient implementation in a robust, cross-platform, object-oriented software package. In this body of research, we (1) examine …

Wavelength Modulation Spectroscopy Of Water Vapor And Line Center Stabilization At 1.462 Μm For Lidar Applications, Colleen Marie Fitzgerald

Electrical & Computer Engineering Theses & Dissertations

Wavelength modulation spectroscopy was employed to investigate water vapor absorption lines in the 1.462 µm wavelength region using an external-cavity diode laser. These measurements were necessary in the development of a lidar (light detection and ranging) instrument for differential absorption measurement of the concentration and movement of water vapor in the Earth's atmosphere. Differential absorption measurements require that the laser frequency remain stable throughout the duration of the measurement. To ensure this stability, the laser output wavelength is monitored and a feedback control loop set up to minimize laser line drift. Three lines were investigated in the 1.462 µm region. …

Theory Of Sic Schottky Barrier Conduction And Model Analysis For Diode Breakdown With And Without Screw Dislocations, Lifeng Zheng

Electrical & Computer Engineering Theses & Dissertations

Silicon Carbide is a very promising candidate for applications in high-power, high-temperature, and high-radiation conditions under which conventional semiconductors cannot perform adequately. However, the SiC processing technology has not yet reached maturity. There is also limited knowledge of its physical and chemical characteristics, and its device behavior is not well understood. The aim of this thesis is to analyze two specific problems in the SiC area. The first issue involves the large discrepancy between experimental I - V characteristics of SiC Schottky diodes and their theoretical values. The observed data, especially at low voltages, is found to be orders of …

A Comparison Of Quasi-Static Indentation Testing To Low Velocity Impact Testing, Michael J. Douglas

Mechanical & Aerospace Engineering Theses & Dissertations

A static test method for modeling low-velocity foreign object impact events to composites would prove to be very beneficial to researchers since much more data can be obtained from a static test than from an impact test. In order to examine if this is feasible, a series of static indentation and low velocity impact tests were carried out and compared. Square specimens of many sizes and thicknesses were utilized to cover the array of types of low velocity impact events. Laminates with a rt/4 stacking sequence were employed since this is by far the most common type of engineering laminate. …

Improving Co-Generation Plant Performance Using Computer Modeling Software: A Parametric Study, Gerald R. Munyan

Mechanical & Aerospace Engineering Theses & Dissertations

The desire to optimize plant performance continues to direct the goals of design and plant engineers associated with larger thermal systems. With the increasing availability of software designed for modeling thermal systems, the task of improving plant performance continues to develop. The ability to model a facility using a commercially available software package allows the design engineer and plant engineer to investigate the effects of variations in plant conditions or components on overall plant operations.

An analysis of the Kirk Lumber Company's co-generating facility was performed using the modeling program PROSIM written by the consulting engineering firm Endat Oy, of …

A Generic Object-Oriented Server Model, Brian Douglas Jones

Electrical & Computer Engineering Theses & Dissertations

The purpose of this paper is to introduce a generic, object-oriented model for the simulation of networks of queues. Generic simulation modeling provides robust ways of laying out processes in stochastic, event driven simulations. The approach taken is to define a methodology that will be implementation independent, termed the Generic Server Simulation Model (GSSM); thus, leaving the implementers to choose the best (most suited for their use) means of implementation. GSSM uses many object-oriented concepts to provide its basic structure and has in its design the ability to take advantage of these object-oriented concepts, including reuse of (existing) code. GSSM …

Process Flow Optimization Studies Through Discrete Event Simulation, Milind Chokshi

Electrical & Computer Engineering Theses & Dissertations

Computer-aided simulation has begun to emerge as a powerful tool for numerical analysis of the behavior and anticipated performance of industrial systems and their optimization. Applications include materials handling, storage and controls systems, prediction of manufacturing efficiencies, and production optimization. Simulations are used to test baseline models and subsequently analyze new production concepts, operating strategies, and planned procedures prior to costly implementation.

The study of process flows in a manufacturing environment is difficult due to its inherent stochastic nature. Breakdown of the sub-systems and failures of machines is a random process and needs to be solved based on concepts of …

A Digital Pressure Sensor Data Acquisition System In A Wind Tunnel Model, John J. Novakoski

Electrical & Computer Engineering Theses & Dissertations

Pressure measurements on wind tunnel models provide an important aid to overall aerodynamic analysis and design of aircraft and vehicles. Most pressure measurements in wind tunnels are made using analog pressure sensors with interfacing electronics that connect to an external data acquisition unit. Some of desirable features of an improved pressure measurement system are that it be: 1) model embeddable, 2) inherently digital in nature, 3) intelligent, and 4) controllable by a remote computer.

An intelligent, model-embedded, eight-channel digital pressure sensor system has been developed and tested in a wind tunnel. The implemented system consists of Micro-Electro-Mechanical System (MEMS) digital …

An Integrated Engineering-Computation Framework For Collaborative Engineering: An Application In Project Management, Hisham Mohamed El-Sayed Abdelsalam

Mechanical & Aerospace Engineering Theses & Dissertations

Today's engineering applications suffer from a severe integration problem. Engineering, the entire process, consists of a myriad of individual, often complex, tasks. Most computer tools support particular tasks in engineering, but the output of one tool is different from the others'. Thus, the users must re-enter the relevant information in the format required by another tool. Moreover, usually in the development process of a new product/process, several teams of engineers with different backgrounds/responsibilities are involved, for example mechanical engineers, cost estimators, manufacturing engineers, quality engineers, and project manager. Engineers need a tool(s) to share technical and managerial information and to …

Modeling The Growth Dynamics Of Antarctic Krill Euphausia Superba, Eileen E. Hofmann, Cathy M. Lascara

CCPO Publications

A time-dependent, size-structured, bioenergetically based model was developed to examine the growth dynamics of Antarctic krill Euphausia superba 2 to 60 mm in size. The metabolic processes included in the model are ingestion, a baseline respiration, respiratory losses due to feeding and digestion, and an activity-based respiration factor. The total of these processes, net production, was used as the basis for determining the growth or shrinkage of individuals. Size-dependent parameterizations for the metabolic processes were constructed from field and laboratory measurements. Environmental effects were included through time series of pelagic phytoplankton concentration that were derived from data sets collected west …

Part 2: The State Of Education, Regional Studies Institute, Old Dominion University

State of the Region Reports: Hampton Roads

(First Paragraph) Few things are more important to adults in Hampton Roads than the quality of their K-12 schools. These schools, and the students within their classrooms, represent the fondest hopes of this generation for a prosperous future. Many citizens and parents are willing to expend countless hours helping to maintain the quality of their schools and, to the extent they are able, make them even better. Pity the political leader who comes to be viewed as "anti-education." From the latest related statewide initiatives to more localized concerns, K-12 schools are always a focal point of the news in Hampton …

Selection Of Curricular Topics Using Extensions Of Quality Function Deployment, Paul Kauffmann, Abel Fernandez, Charles Keating, Derya Jacobs, Resit Unal

Engineering Management & Systems Engineering Faculty Publications

Decision science can be an effective tool for enhancing organizational participation during strategic and complex decision making. This involvement develops a group consensus for relating organizational goals and the methods to achieve them. This paper describes an application of Quality Function Deployment (QFD) to define curricular topics that meet program objectives. Based on the ability of QFD to establish relationships, the model identifies the most important topics and quantifies their impact on meeting program goals. The model was developed to support restructuring of a Masters of Engineering Management degree program. The model supported decisions in selecting and prioritizing the required …

Series Operation Of Direct Current Xenon Chloride Excimer Sources, Ahmed El-Habachi, Wenhui Shi, Mohamed Moselhy, Robert H. Stark, Karl H. Schoenbach

Bioelectrics Publications

Stable, direct current microhollow cathode discharges in mixtures of hydrochloric acid, hydrogen, xenon, and neon have been generated in a pressure range of 200–1150 Torr. The cathode hole diameter was 250 μm. Sustaining voltages range from 180 to 250 V at current levels of up to 5 mA. The discharges are strong sources of xenon chloride excimer emission at a wavelength of 308 nm. Internal efficiencies of approximately 3% have been reached at a pressure of 1050 Torr. The spectral radiant power at this pressure was measured as 5 mW/nm at 308 nm for a 3 mA discharge. By using …

Electroporation Dynamics In Biological Cells Subjected To Ultrafast Electrical Pulses: A Numerical Simulation Study, R. P. Joshi, K. H. Schoenbach

Bioelectrics Publications

A model analysis of electroporation dynamics in biological cells has been carried out based on the Smoluchowski equation. Results of the cellular response to short, electric pulses are presented, taking account of the growth and resealing dynamics of transient aqueous pores. It is shown that the application of large voltages alone may not be sufficient to cause irreversible breakdown, if the time duration is too short. Failure to cause irreversible damage at small pulse widths could be attributed to the time inadequacy for pores to grow and expand beyond a critical threshold radius. In agreement with earlier studies, it is …

Blending Hf Radar And Model Velocities In Monterey Bay Through Normal Mode Analysis, B. L. Lipphardt Jr., A. D. Kirwan Jr., C. E. Grosch, J. K. Lewis, J. D. Paduan

CCPO Publications

Nowcasts of the surface velocity field in Monterey Bay are made for the period August 1-9, 1994, using HF radar observations blended with results from a primitive equation model. A spectral method called normal mode analysis was used. Objective spatial and temporal filtering were performed, and stream function, velocity potential, relative vorticity, and horizontal divergence were calculated over the domain. This type of nowcasting permits global spectral analysis of mode amplitudes, calculation of enstrophy, and additional analyses using tools like empirical orthogonal functions. The nowcasts reported here include open boundary flow information from the numerical model. Nowcasts using no open …

Can An Optical Plankton Counter Produce Reasonable Estimates Of Zooplankton Abundance And Biovolume In Water With High Detritus?, X. Zhang, M. Roman, A. Sanford, H. Adolf, C. Lascara, R. Burgett

CCPO Publications

The Optical Plankton Counter (OPC) has been used in oceanic and fresh waters to estimate zooplankton abundance and biovolume. However, it is not clear whether the OPC can produce accurate estimates of zooplankton abundance and biovolume in waters with high detritus. In order to test the capability of the OPC to estimate zooplankton abundance and biovolume in Chesapeake Bay, two sets of laboratory experiments were conducted using water with high detritus concentrations collected from the upper Choptank estuary of Chesapeake Bay and laboratory cultured Artemia. Our results suggest that the OPC is able to produce accurate estimates of zooplankton biovolume …

Convergence Of Lateral Flow Along A Coastal Plain Estuary, Arnoldo Valle-Levinson, Chunyan Li, Kuo-Chuin Wong, Kamazima M. M. Lwiza

CCPO Publications

A set of velocity profiles obtained in the James River estuary with an acoustic Doppler current profiler was used in combination with the results of an analytic tidal model to depict the appearance of surface lateral flow convergences (δv/δy) during both flood and ebb stages of the tidal cycle. The bathymetry of the estuary was characterized by a main channel and a secondary channel separated by relatively narrow shoals. Lateral surface flow convergences appeared over the edges of the channels and were produced by the phase lag of the flow in the channel relative to the …

Fortnightly Variability In The Transverse Dynamics Of A Coastal Plain Estuary, Arnoldo Valle-Levinson, Kuo-Chuin Wong, Kamazima M. M. Lwiza

CCPO Publications

Current velocity and water density profiles were obtained along two crossestuary transects with the purpose of determining the fortnightly variability of the transverse dynamics in a partially stratified coastal plain estuary. The profiles were measured with a towed acoustic Doppler current profiler and a conductivity-temperaturedepth recorder in the James River estuary, Virginia. The cross-estuary transects were sampled during the spring tides of October 26-27, 1996, and the ensuing neap tides of November 2-3, 1996. The transects were-4 km long, featured a bathymetry that consisted of a channel flanked by shoals, and were sampled repeatedly during two semidiurnal tidal cycles (25 …

On The Sources Of Weddell Gyre Antarctic Bottom Water, Michael P. Meredith, Ricardo A. Locarnini, Kim A. Van Scoy, Andrew J. Watson, Karen J. Heywood, Brian A. King

CCPO Publications

In March-April 1995, as part of the World Ocean Circulation Experiment section A23, we completed 49 hydrographic stations across the Weddell Gyre and southern Antarctic Circumpolar Current, from the Antarctic continental shelf (72.5°S, 16.5°W) to South Georgia (55°S, 34.5°W). Chlorofiuorocarbon (CFC11, CFC-12, and CFC-113) data collected at these stations reveal that distinct sources renew the Antarctic Bottom Water (defined as waters with potential temperatures less than 0°C) of the Weddell Gyre. Weddell Sea Bottom Water (defined as waters with potential temperatures less than- 0.7°C) formed in the western Weddell Sea has CFC concentrations about 5 to 6 times higher in …

Soapbox: The Academic Research Fleet: An Exciting Time For Renewal, Larry Atkinson

CCPO Publications

(First Paragraph) Academic research ships in the United States are the envy of many scientists around the world. A great strength of our system is the diversity of ships and operators: users have a choice, the system can change. A weakness of the system is that very diversity: sometimes it is hard for us to act together. Nevertheless, we now must act together. The vitality of the academic fleet in the coming decades is at stake. The reason is simply because many of our ships, especially in the intermediate size range, will soon reach the end of their useful life.