Digital Commons Network^™

Coherent Differential Absorption Lidar For Combined Measurement Of Wind And Trace Atmospheric Gases, Grady James Koch

Electrical & Computer Engineering Theses & Dissertations

A lidar system was developed for making combined range-resolved measurements of wind speed and direction, water vapor concentration, and carbon dioxide concentration in the atmosphere. This lidar combines the coherent Doppler technique for wind detection and the differential absorption lidar (DIAL) technique to provide a multifunctional capability. DIAL and coherent lidars have traditionally been thought of and implemented as separate instruments, but the research reported here has shown a demonstration of combining the coherent and DIAL techniques into a single instrument using solid-state lasers. The lasers used are of Ho:Tm:YLF, which operates at a wavelength of 2 μm. This wavelength …

A Software Reliability Model Combining Representative And Directed Testing, Brian Michael Mitchell

Computer Science Theses & Dissertations

Traditionally, software reliability models have required that failure data be gathered using only representative testing methods. Over time, however, representative testing becomes inherently less effective as a means of improving the actual quality of the software under test. Additionally, the use of failure data based on observations made during representative testing has been criticized because of the statistical noise inherent in this type of data. In this dissertation, a testing method is proposed to make reliability testing more efficient and accurate. Representative testing is used early, when the rate of fault revelation is high. Directed testing is used later in …

On Multifunctional Collaborative Methods In Engineering Science, Jonathan B. Ransom Sr.

Mechanical & Aerospace Engineering Theses & Dissertations

Engineers are challenged to produce better designs in less time and for less cost. Hence, to investigate novel and revolutionary design concepts, accurate, high-fidelity data must be assimilated rapidly into the design, analysis and simulation process. This data assimilation should consider diverse mathematical modeling and multi-discipline interactions necessitated by concepts exploiting advanced materials and structures. Integrated high-fidelity methods with diverse engineering applications provide the enabling technologies to assimilate these high-fidelity, multi-disciplinary data rapidly at an early stage in the design. These integrated methods must be multifunctional, collaborative and applicable to the general field of engineering science and mechanics.

Multifunctional methodologies …

A Comparison Of Phytoplankton Communities In Lake Prince And The Western Branch Reservoir, Suffolk, Virginia, Cara Marie Muscio

Biological Sciences Theses & Dissertations

Lake Prince and the Western Branch Reservoir are two eutrophic bodies of water located in Suffolk, Virginia. Lake Prince and its two small tributaries join the Western branch via a constructed spillway. This lake system is a source of water for the surrounding municipalities, and a recreational area for community citizens. In the past, these bodies of water had repeated incidents of low oxygen and nuisance algal blooms, particularly cyanobacteria species. As a result aerators have been installed in the main body of both Lake Prince and the Western Branch Reservoir. In addition, a pipeline has been installed from North …

The Cowboy's Dirty Laundry, Kurt Bolotin

English Theses & Dissertations

"The Cowboy's Dirty Laundry" represents three years spent writing, workshopping, and revising literary short stories. Each explores themes common to people in conflict with themselves. They are stories of self-destruction, regret, loneliness, and adaptation.

The title story, "The Cowboy's Dirty Laundry," is a first-person narrative about a man struggling with a woman he loves but mistreats. "The Summer Sue Came Home" and "The Good Light in Charley's Garage" evolved from a workshop assignment to write about regret. Charley and Sue appear in both stories, the first told from Sue's point-of-view when they are young, the second told from Charley's point—of-view …

The Anaconda's Head: The U.S. Consular Service In British North America, 1861-1866, Myron Becker

History Theses & Dissertations

Although the story of how Confederates attempted to spur rebellion in the North during the Civil War has been the subject of historical research, virtually nothing has been published about the work of Northern operatives in Canada during the period 1861-1866. Extensive research in the Library of Congress, the National Archives, and the Royal Canadian Archives and Library demonstrates that a team of U.S. Consuls and detectives led by David 8. Thurston thwarted Confederate efforts to launch those insurrections. The Southern strategy was to create so much havoc that the Union would negotiate a peace that would preserve the Confederacy. …

The Effects Of Training In Teamwork Skills On Intact Student Teams, Lara Bryan Tedrow

Psychology Theses & Dissertations

This study explored the effect of a theory-based training program in teamwork skills on the performance, satisfaction and teamwork skills of students working in teams on class projects. Twenty-seven teams of students were recruited from six different classes across departments at a local university. Teams were assigned to either a placebo session or an experimental training session, which trained them in teamwork skills, based on the Dickinson and McIntyre (1997) model of teamwork. Teams were then compared on project grades, ratings of satisfaction on the Group Attitude Scale (Evans & Jarvis, 1986) and ratings of teamwork on the Teamwork Component …

Adsorption Of Inorganic And Organic Ligands Onto Aluminum Hydroxide And Its Effect In Water Treatment, Peter Pommerenk

Civil & Environmental Engineering Theses & Dissertations

The inorganic anions fluoride, sulfate, and orthophosphate are ubiquitous substances in aqueous environments. These chemicals are also applied in drinking water treatment processes where fluoridation, coagulation with sulfate-based metal salts, or the use of passivating corrosion inhibitors or sequestering agents is practiced. If these ions are present at elevated levels in raw waters or added in the treatment train at points other than directly before entering a finished water reservoir, they can exert a negative influence on the removal of particles and natural organic matter.

Although the water chemistry of these inorganic ions seems to be well understood, their potential …

Fighting "Don't Know, Don't Care": The Fcda's Public Education Quest, Rachel M. Mihalovich

History Theses & Dissertations

The Federal Civil Defense Administration (FCDA) was created in December 1950 to prepare the civilian population of the United States to survive and recover from a nuclear attack by the Soviet Union and its allies. Contemporary civil defense theory dictated that this goal should be met by educating the American public in order to avoid a negative psychological reaction that would prevent survival and recovery. In order to evaluate the success of the FCDA's civil defense program, this study will investigate the composition of the FCDA and its public education program.

This study utilized several types of sources in evaluating …

Psychophysiological Measures And Performance Effects In An Adaptive Sustained Attention Task, Gerald Alan Hadley

Psychology Theses & Dissertations

This experiment examined the effect of a biocybernetic system that had been successfully used to control an adaptive automation compensatory tracking task (Freeman, Mikulka, Prinzel, & Scerbo, 1999; Pope, Bogart, & Bartolome, 1995). The present study applied this adaptive automation system to a vigilance task. Recordings of EEG activity were used to derive an index of task engagement, beta/(alpha+ theta). A training session was used to establish a baseline level of this index. Index levels above baseline reflected an increase in arousal, while levels below baseline indicated decreased arousal. Three groups (production, reception, and control) performed the task which presented …

Institutionalized Discrimination And Sectarianism In Northern Ireland, Darlene E. Hall

Sociology & Criminal Justice Theses & Dissertations

The purpose of this research and subsequent thesis is to explore the issue of institutionalized discrimination, sectarian and political harassment, and victimization in the North of Ireland.

Understanding the situation in the North of Ireland will contribute to an understanding of how minority groups experience oppression and domination from the power elite groups. Extralegal, improper, or unwarranted force by police and security force members receives special attention. Conflict theorists such as Bailey (1996), Skolnick and Fyfe (1993), Quinney (1970) and Chambliss (1994) are reviewed regarding the misuse of force by police. A review of literature reveals that discrimination and sectarian …

Effects Of Human Disturbances On The Behavior Of Dabbling Ducks, Melissa Lynn Pease

Biological Sciences Theses & Dissertations

Disturbance of wintering and migrating birds by human activities can cause birds to expend energy in avoidance of humans and reduces the time available for resting and feeding at a time in the annual cycle when fat deposition and energy conservation are important. Also, human disturbances can effectively cause habitat loss by displacing birds from feeding or resting habitat. Managers of natural resources are increasingly faced with decisions about the types and amounts of public use that should be allowed without lowering the value of the resource for wildlife. In order for managers to make decisions about how to minimize …

A Substructuring Technique With Application To Spot Weld Placement Design, Yang Wang

Mechanical & Aerospace Engineering Theses & Dissertations

It is quite common in the industry to use various interface methods, such as welding, fasteners, bolts, adhesive bonding, etc., to join substructures together. The quality of the assembled structure is directly related to the type of the interface methods used in the manufacturing process. Thus, it is important to include the interface conditions as part of design variables in any design process. To this end, this work develops a reanalysis method that can efficiently analyze structures with variations on the interface conditions. This reanalysis method is based upon a new two-step substructuring technique. The first step performs substructural level …

Spice-Based Heat Transport Model For Non-Intrusive Thermal Diagnostic Applications, Michael Stelzer

Electrical & Computer Engineering Theses & Dissertations

Nondestructive material testing and diagnostics play an important role in reliability analysis, component wear-out testing, life-cycle estimates, and safety inspections. Of the several techniques available for nondestructive inspections, thermal analysis has been chosen to be the focus of this thesis research. An equivalence between the system of equations for the heat flow problem, and the variables of circuit theory suggests that an electrical model can be constructed to represent the actual thermal system. This electrical model is constructed based upon a finite difference discretization of the heat flow equation. Using these associations a basic one-dimensional electrical model has been constructed …

Development And Testing Of A Cfd-Based Optimization System For Axially Symmetric Rocket Nozzles, John-Paul Shebalin

Mechanical & Aerospace Engineering Theses & Dissertations

A software system has been developed to optimize rocket nozzle shapes for maximizing their performance. It has been established in the literature that one can use computer-based optimization with the parabolized Navier-Stokes equations to optimize the dimensions of low Reynolds number rocket nozzles-micronozzles. The Nozzle Optimization System described herein uses the full Navier-Stokes equations to optimize any axially symmetric rocket nozzle for which a converged solution can be obtained.

Four nozzles are optimized using this system-conical and contoured micronozzles and conical and contoured Space Transportation System(STS)-class nozzles. The optimum cone angle (O_cone) for the conical micronozzle was …

Mitigation Of Water Vapor Interference For Infrared Polarization-Modulated Gas Filter Correlation Radiometry, David K. Lockwood

Electrical & Computer Engineering Theses & Dissertations

Gas filter correlation radiometry (GFCR) is a high-resolution, high-specificity technique for sensing gaseous species. A variation of absorption spectroscopy, GFCR has a long-proven record on orbital platforms for quantitative measurements of atmospheric constituents, as well as common usage in ground-based sensing applications. PMGFCR (Polarization-modulated GFCR) is a recent refinement of the technique with several advantages over the traditional method, including reducing the number of photodetectors required, increased sensitivity, and elimination of moving parts.

To date, no infrared remote sensors have successfully measured nitric oxide (NO) in vehicle exhaust due to spectral overlap by strong water vapor (H₂O_{v …}

An Examination Of The First Sediment Cores From Mountain Lake, Giles County, Virginia, For Diatoms And Pollen, Jon C. Cawley, Bruce C. Parker, Terry L. Hufford

Virginia Journal of Science

Mountain Lake, Virginia is a small, unique, oligotrophic, subalpine ecosystem in the southern Appalachians. Its geology, origin, climate, and history have influenced its morphometry, and therefore its sedimentology and algal flora. Radiocarbon dates establish specific Mountain Lake sediment ages at 1800, 4100, and 6100 years BP. Sediment core analysis suggests at least 6 prolonged periods when Mountain Lake probably was nearly dry or very small in size. These individual low-water periods (at approximately 100, 400, 900, 1200, 1800 and 4100 years BP) are evidenced by changes in diatom and pollen content, sedimentary erosion features, and the presence of wood fragments, …

Effects Of Collection, Transport, And Redeployment Methods On Natural Mortality Of Rangia Cuneata (Mactridae) Used In Biomonitoring Studies, Eugene G. Maurakis, David V. Grimes, William C. Gretes

Virginia Journal of Science

Sporadic, high mortality in test populations of wedge clams (Rangia cuneata) has limited the potential for using this otherwise desirable test organism in biomonitoring studies. To determine whether high mortality was due to ontogenic or experimental variables, a two-phased study was conducted. In phase I, mortality of collected and re-deployed wedge clams, subjected to varying transport conditions, was determined at 7, 14, 21 and 60 days re-deployment. The use of three transport times (1, 2, 3 hr.), two vehicle conditions (open, closed) and three transport treatments (open, closed, iced containers) yielded 18 test groups. Individual test group mortalities …

Jeffress Research Grant Awards, Virginia Journal Of Science

Virginia Journal of Science

Announcements of the Jeffress Research Grants that have been awarded in 2000.

Production Of A Novel Copper-Binding Ligand By Marine Synechococcus (Cyanobacteria) In Response To Toxic Concentrations Of Copper, Arunsi C. Brown, Andrew S. Gordon

Virginia Journal of Science

Marine Synechococcus spp. are extremely sensitive to copper toxicity. Some strains have been shown to produce high-affinity, extracellular ligands of unknown structure which form complexes with free cupric ion. They are also known to produce metallothioneins (MT) in response to cadmium and zinc stress. In the present study, marine Synechococcus PCC 73109 (Agmenellum quadruplicatum BG-1) (Van Baalen) was exposed to three concentrations of CuSO₄ for various times. Size exclusion chromatography, atomic absorption spectrophotometry, and reverse phase HPLC were used to isolate an intracellular copper binding ligand of low molecular weight (< 6,500 Da). The ligand was detected after exposure to ≥ 8 μM CuSO₄ for 2 hr in BG-11 medium. …

Resonant Energy Transfer From Argon Dimers To Atomic Oxygen In Microhollow Cathode Discharges, M. Moselhy, R. H. Stark, K. H. Schoenbach, U. Kogelschatz

Bioelectrics Publications

The emission of atomic oxygen lines at 130.2 and 130.5 nm from a microhollow cathode discharge in argon with oxygen added indicates resonant energy transfer from argon dimers to oxygen atoms. The internal efficiency of the vacuum-ultraviolet (VUV) radiation was measured as 0.7% for a discharge in 1100 Torr argon with 0.1% oxygen added. The direct current VUV point source operates at voltages below 300 V and at current levels of milliamperes.

Self-Consistent Simulations Of Electroporation Dynamics In Biological Cells Subjected To Ultrashort Electrical Pulses, R. P. Joshi, Q. Hu, R. Aly, K. H. Schoenbach, H. P. Hjalmarson

Bioelectrics Publications

The temporal dynamics of electroporation of cells subjected to ultrashort voltage pulses are studied based on a coupled scheme involving the Laplace, Nernst-Plank, and Smoluchowski equations. A pore radius dependent energy barrier for ionic transport, accounts for cellular variations. It is shown that a finite time delay exists in pore formation, and leads to a transient overshoot of the transmembrane potential V_mem beyond 1.0 V. Pore resealing is shown to consist of an initial fast process, a 10⁻⁴s delay, followed by a much slower closing at a time constant of about 10 ⁻¹s. This establishes a …

Electroproduction Of The Λ(1520) Hyperon, M. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, S. E. Kuhn, R. A. Niyazov, L. B. Weinstein, Et Al., The Clas Collaboration

Physics Faculty Publications

The reaction e^→pe′K⁺Λ(1520) with Λ(1520)→p′K⁻ was studied at electron beam energies of 4.05, 4.25, and 4.46 GeV, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cos θ_K+, φ_K+, Q², and W dependencies of Λ(1520) electroproduction are presented for the kinematic region 0.9 < Q² < 2.4 GeV² and 1.95 < W < 2.65 GeV. Also, the Q² dependence of the Λ(1520) decay angular distribution is presented for the first time. The cosθ_K+ angular distributions suggest t-channel diagrams dominate the production process. Fits to the Λ(1520) t-channel helicity frame decay angular distributions indicate the m …

The Ep → E'P Η Reaction At And Above The S₁₁ (1535) Baryon Resonance, R. Thompson, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, Et Al., The Clas Collaboration

Physics Faculty Publications

New cross sections for the reaction ep → ep η are reported for total center of mass energy W = 1.5-1.86 GeV and invariant momentum transfer Q² = 0.25-1.5 (GeV/c)². This large kinematic range allows extraction of important new information about response functions, photocouplings, and etaN coupling strengths of baryon resonances. Newly observed structure at W ~ 1.65 GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S₁₁(1535) resonance.

Exclusive Electroproduction Of ᵠ Mesons At 4.2 Gev, M. Bektasoglu, L. Ciciani, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, S. E. Kuhn, L. M. Qin, F. Sabatié, L. B. Weinstein, Et Al., The Clas Collaboration

Physics Faculty Publications

We studied the exclusive reaction ep → e' p' ᵠ using the ᵠ →K⁺K^- decay mode. The data were collected using a 4.2 GeV incident electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Our experiment covers the range in Q² from 0.7 to 2.2 GeV²and W from 2.0 to 2.6 GeV. Taken together with all previous data, we find a consistent picture of ᵠ production on the proton. Our measurement shows the expected decrease of the t slope with the vector-meson formation time c Δ t …

Arc - An Oai Service Provider For Digital Library Federation, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Michael L. Nelson

Computer Science Faculty Publications

The usefulness of the many on-line journals and scientific digital libraries that exist today is limited by the inability to federate these resources through a unified interface. The Open Archive Initiative (OAI) is one major effort to address technical interoperability among distributed archives. The objective of OAI is to develop a framework to facilitate the discovery of content in distributed archives. In this paper, we describe our experience and lessons learned in building Arc, the first federated searching service based on the OAI protocol. Arc harvests metadata from several OAI compliant archives, normalizes them, and stores them in a search …

Smart Objects And Open Archives, Michael L. Nelson, Kurt Maly

Computer Science Faculty Publications

Within the context of digital libraries (DLs), we are making information objects "first-class citizens". We decouple information objects from the systems used for their storage and retrieval, allowing the technology for both DLs and information content to progress independently. We believe dismantling the stovepipe of "DL-archive-content" is the first step in building richer DL experiences for users and insuring the long-term survivability of digital information. To demonstrate this partitioning between DLs, archives and information content, we introduce "buckets": aggregative, intelligent, object-oriented constructs for publishing in digital libraries. Buckets exist within the "Smart Object, Dumb Archive" (SODA) DL model, which promotes …

Global Engineering In An Interconnected World: An Upper Division General Education Cluster At Old Dominion University, Sushil Chaturvedi, Gary Crossman, William Swart, Joseph Betit

Mechanical & Aerospace Engineering Faculty Publications

The “Global Engineering in an Interconnected World” cluster of courses fosters among students an awareness and understanding of global technology, quality assurance standards, and differences in cultural, communication, and business practices and their impact on a global work environment. This cluster will prepare the growing numbers of students who will accept employment with global firms or find themselves part of a merger or strategic alliance involving multinational corporations. This newly approved cluster of five courses described in the paper has been approved by the University for satisfying University upper-division general education requirements. As a consequence, students choosing this route to …

Learning Style And Laboratory Preference: A Study Of Middle School Technology Education Teachers In Virginia, Philip A. Reed

STEMPS Faculty Publications

Laboratory instruction has long been a cornerstone of technology education pedagogy. The French realized the potential for technical laboratory instruction within general education in 1865 (Bennett, 1926). By the 1880s, the United States also realized the benefits of the technical laboratory for general education (Anderson, 1926). Despite these early roots and the continued practice of utilizing laboratory instruction within technology education, there is little research to support this teaching method. McCrory (1987) noted that there were no studies on laboratories (excluding machine safety) or new technology education equipment during the period 1980-1986. Laboratory studies during the period 1987-1993 concentrated on …

Stm And Electrochemical Investigation Of Homoepitaxial Boron-Doped Cvd Diamond Films, John B. Cooper, Jason A. Moulton, Sacharia Albin, Bing Xiao

Chemistry & Biochemistry Faculty Publications

Homoepitaxial growth of boron-doped CVD diamond films was carried out on (100) and (111) oriented substrates. Atomic resolution images were obtained for both (100) and (111) surfaces using scanning tunneling microscopy. STM images reveal the presence of a 2x1-monohydride reconstruction for the untreated (100) surface and a lxl reconstruction for the untreated (111) surface. No other atomically resolved reconstructions were observed under a wide range of growth conditions. Non-aqueous electrochemical investigations were carried out on the films exhibiting atomically resolved reconstructions. Evidence for potential-induced surface-reconstruction and surface chemical modification of the (100) 2xl-monohydride surface has been observed.