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Modeling A High-Efficiency Ozone Injection Contactor, L. Bernard Garrett Jr.

Civil & Environmental Engineering Theses & Dissertations

Significant research over the last several years has focused on applying modeling equations for estimating design parameters of ozone contactors. Much of this research has focused on fine bubble diffusers, which are the more widely used injection system for ozone contactors in the U.S. A recently developed design incorporates a new ozone injection system called a sidestream venturi injector (SVI) which is used with a co-current downflow column to achieve very high ozone mass transfer efficiencies. A pilot study conducted at the Harwood's Mill water treatment plant in Newport News, Virginia, from June to December 1993 demonstrated the high mass …

Resource/Dataflow Graph Operating System Development, Sriram J. Coimbatore

Electrical & Computer Engineering Theses & Dissertations

Implementation of a new dataflow schedule model is the objective of this thesis. The dataflow model algorithm called the resource/dataflow graph model is implemented on a peer-to-peer communication network comprising of six personal computers. This dataflow model is implemented making use of an earlier dataflow model called ATAMM (Algorithm to Architecture Mapping Model) developed by ODU and National Aeronautics and Space Administration (NASA). Development issues include modification of the RDFG testbed operating system and a scheme to transfer data buffers using the ethernet channel from one processor to another processor. This, in turn, equips each sub-module of an application with …

An Investigation Of Software Reliability Models, Pamela Elaine Bowman

Computer Science Theses & Dissertations

Many software reliability models have been promoted in the literature in an attempt to provide a meaningful response to the growing need to know the reliability of software during and after the development process. However, there are well-founded concerns as to the accuracy of the individual model, as well as to the choice of which model to use for a particular program. A recent experiment based on the debugging history of a partially debugged program used a gold version to label a debugging graph from replicated data. This experiment concluded that presenting the replicated data to the models in a …

Human Immunodeficiency Virus (Hiv)/Hepatitis B Virus (Hbv) Risk Perception Related To Needlestick Injuries At A Medical School In Norfolk, Virginia, Ronald B. Hartman

Community & Environmental Health Theses & Dissertations

A limited number of studies have been conducted to assess the perceptions of risk of medical students and residents for acquiring Human Immunodeficiency Virus (HIV) or Hepatitis B Virus (HBV) via percutaneous (needlestick) injuries while performing clinical training. The purpose of this study is to investigate these perceptions of risk, and to determine whether there is an association between a high perception of risk and a low incidence of needlestick injury. The method of investigation was a four-page survey questionnaire. The instrument was investigated for reliability by use of a pilot study with a small group of medical students and …

Two-Dimensional Drift-Diffusion Simulations Of Silicon Avalanche Shaper (Sas) Devices For High Power Applications, Hamid Jalali

Electrical & Computer Engineering Theses & Dissertations

Silicon Avalanche Shaper devices have been projected as being important components of an inexpensive, semiconductor-based technology for high power switching applications. The primary advantage of this technology is that it is based on Silicon material which is easy to fabricate and has a well established processing technology. Unlike other high power technologies, the SAS devices do not rely on external optical triggering which eliminates the need for lasers and related optical circuitry.

The SAS based high power switching technology has been pioneered and tested by a Russian group. Though preliminary results have been very encouraging, the device reliability and its …

Cross-Cultural Differences And Intercultural Cooperation In The Context Of Change And Uncertainty: Americans And Finns In The Workplace, Maija Llisa Herweg

Engineering Management & Systems Engineering Theses & Dissertations

American and Finnish workers in financial institutions in the United States and in Finland were interviewed in their respective languages to explore cross-cultural differences in response to change and uncertainty in the work place. Changes were explored in the domains of organizational, process, procedure and work content, and technological changes in the work place. As a point of departure for this study, Hofstede's IBM study, as it pertains to Uncertainty Avoidance--a measure he used to evaluate culture-based resistance to change--was used for this study.

Differences in the kinds of change considered difficult to adjust to were found in the cross-cultural …

Optimality And Construction Of Designs With Generalized Group Divisible Structure, Sudesh K. Srivastav

Mathematics & Statistics Theses & Dissertations

This thesis is an investigation of the optimality and construction problems attendant to the assignment of v treatments to experimental units in b blocks of size k, paying special attention to settings for which equal replication of the treatments is not possible. The model is that of one way elimination of heterogeneity, in which the expectation of an observation on treatment i in block j is T_i + βj (treatment effect + block effect), where T_i and βj are unknown constants, 1 ≤ i ≤ v and 1 ≤ j ≤ b. All observations are assumed to …

Comprehensive Conjunctive-Use Management Of Connected Surface Water Groundwater Systems Using Stochastic Inputs And Uncertainties, Seshadri Suryanarayana

Civil & Environmental Engineering Theses & Dissertations

A comprehensive conjunctive-use management model is developed. The dynamics of flow and solute transport processes in connected surface water groundwater systems are integrated by a dual programming management model. The governing aquifer flow parameters and streamflows are treated as stochastic random processes. Multiple realizations of the random field are generated and are explicitly incorporated in a non-linear optimization model along with other system, environmental, and management constraints. To facilitate management of large aquifer systems, a linked simulation-optimization approach is used. The simulation program generates the response matrices for flow and transport processes. The management model then determines optimal well discharges …

Numerical Prediction Of Turbulent Diffusion Flames Formed By Cylindrical Tube Injector, Ali S. Kheireddine

Mechanical & Aerospace Engineering Theses & Dissertations

This work summarizes numerical results for a diffusion flame formed from a cylindrical tube fuel injector, issuing gaseous fuel jet vertically in a quiescent atmosphere. Both pure fuels as well as fuel mixtures are examined. The primary objective is to predict the flame base height as a function of the jet velocity. A finite volume scheme is used to discretize the time-averaged Navier-Stokes equations for the reacting flow, resulting from the turbulent fuel jet motion. The turbulent stresses, and heat and mass fluxes are computed from the Reynolds stress turbulence model. A chemical kinetics model involving a two-step chemical reaction …

Neuronal Toxicity Of Humoral Factors From Patients With Diabetic Neuropathy And Mechanism Of Neuronal Death On Cultured Adrenergic Neurons: Studies Of Autoimmune Pathogenesis In Diabetic Neuropathy, Dong Liu

Theses and Dissertations in Biomedical Sciences

Diabetic neuropathy is an extremely common medical problem because of the high frequency of diabetes and its complications. Diabetic neuropathy consists of not one, but many patterns of nerve injury, each potentially with its own discrete pathogenic mechanisms. Evidence is accumulating that indicates autoimmunity plays a role in diabetic peripheral neuropathy. However, the significance of immunopathogenesis of diabetic neuropathy is as yet unclear.

Using the N1E-115 mouse neuroblastoma cell line (NB) as a model of the adrenergic autonomic neuron, we found that sera of IDDM patients with neuropathy inhibit growth and differentiation of adrenergic neurons in culture (Pittenger et al, …

An Artificial Life Model Of Engineering Attrition Contemplation: Why Do Federally Employed Civilian Engineers Think Of Quitting?, John William Herweg

Engineering Management & Systems Engineering Theses & Dissertations

The research objective is, using engineer turnover, to develop an Artificial Life (A-Life) model and simulation methodology useful for studying behavioral variables of individuals in an organization.

One consequence of work stress is burnout, and its extreme expression is quitting or turnover. Various models have been used to explain and predict this behavior. Behavior models are useful tools to explore the ability of organizational policies to reduce stress levels and turnover. Advancing the usefulness of models is a goal which assists all research on human behavior. A-Life offers a new and different methodology for this purpose. It provides an ability …

Lattice Truss Structural Response Using Energy Methods, Winfred Scottson Kenner

Mechanical & Aerospace Engineering Theses & Dissertations

A deterministic methodology is presented for developing closed-form deflection equations for two-dimensional and three-dimensional lattice structures. Four types of lattice structures are studied: beams, plates, shells and soft lattices. Castigliano's second theorem, which entails the total strain energy of a structure, is utilized to generate highly accurate results. Derived deflection equations provide new insight into the bending and shear behavior of the four types of lattices, in contrast to classic solutions of similar structures. Lattice derivations utilizing kinetic energy are also presented, and used to examine the free vibration response of simple lattice structures. Derivations utilizing finite element theory for …

Information Warfare: Technology And The Information Advantage, Daniel Matthew Parker

Graduate Program in International Studies Theses & Dissertations

This thesis analyzes information warfare--that emerging form of warfare that attempts to destroy, degrade and exploit the information systems of another, while protecting one's own--in the context of the technology of warfare. Just as one might peel an onion, the analysis proceeds from a general analysis of technology in warfare to the more specific analysis of information warfare as it is currently defined. Information technology is an enabling factor in the emergence of information warfare as a new warfare area. Although it is revolutionizing the way warfare is conducted, the elements of information warfare have been practiced for thousands of …

The Noaa Corps -- A Participant Action Research Of A Uniformed Service Facing Termination, Richard Eugene Marriner Ii

Engineering Management & Systems Engineering Theses & Dissertations

The NOAA Corps is a uniformed service of the Federal Government. It is composed of officers commissioned by the President of the United States as are the officers of the Air Force, Army, Coast Guard, Marines, Navy, and Public Health Service. "NOAA" is the acronym for the National Oceanic and Atmospheric Administration, an agency within the U.S. Department of Commerce.

On January 24, 1996 the Clinton administration formally proposed that the NOAA Corps be terminated on October 1, 1996. If this were to become reality it would be the first time in U.S. History that a uniformed service has been …

Task Interdependence And Teamwork Processes, Kristin Krahl

Psychology Theses & Dissertations

In today's continually expanding and global marketplace, organizations are increasingly relying on teams. The tasks that are performed by these teams are requiring greater interdependency among members as technology becomes more complex. Therefore, there is a need for a valid measure to study the task interdependence among team members. This study developed a measure of task interdependence and provided evidence for the construct validity of the measure using LISREL (Joreskog & Sorbom, 1993). In particular, the task interdependence measure was shown to be distinct from teamwork measures developed in previous research (Rosenstein, 1994). A structural model of relationships among teamwork …

Energy Use Analysis Of A Multi-Unit Housing Facility A Parametric Study, Brian David Cooper

Mechanical & Aerospace Engineering Theses & Dissertations

In the continuing effort to reduce the energy use of buildings, design engineers and architects are called upon to design facilities which are more efficient and use less energy. The prediction of the energy used by a building's systems and occupants, for different design options and combinations, is an important part of the design of an energy efficient building.

An energy use analysis was conducted to determine the accuracy of a computerized building energy analysis simulation when only preliminary design information is available. Additional studies were made to determine the accuracy of the simulation as more detailed design, construction and …

The United State Government Versus John Harrison Surratt: A Study In Attitudes, Thomas Michael Martin

History Theses & Dissertations

The same day on which accused Abraham Lincoln murder conspirator Mary Eugenia Surratt was arrested at her Washington, D.C. boardinghouse, her son and alleged co-conspirator, John Harrison Surratt, was in a small town in northern New York. The arrest of the widow Surratt, however, marks the first of a series of points of departure between the destinies of the mother and the son. She was destined to follow a path from arrest to trial and execution by means of a military commission created by the War Department. John's circuitous route from trans-Atlantic flight to extradition, trial, and dismissal by a …

Progressive Failure Analysis Methodology For Laminated Composite Structures, David Wayne Sleight

Mechanical & Aerospace Engineering Theses & Dissertations

A progressive failure analysis model has been developed for predicting the nonlinear response and failure of laminated composite structures. The progressive failure analysis uses C¹ plate and shell elements based on classical lamination theory to calculate the in-plane stresses. Several failure criteria, including the maximum strain criterion, Hashin's criterion, and Christensen's criterion, are used to predict the failure mechanisms and several options are available to degrade the material properties after failures. The progressive failure analysis model is implemented in COMET and can predict the damage and response of a laminated composite structures from initial loading to final failure.

Rectified Synthesis Of Coupler Driven Four Bar Mechanisms For Two And Three Position Motion Generation, Ramanujam Thiruvenkatachari

Mechanical & Aerospace Engineering Theses & Dissertations

Four-bar mechanisms are widely used in the industry to solve a variety of motion problems. Till recently, their design was based on fundamental kinematics and brute force techniques, resulting in impractical designs and spurious linkages that failed to perform their desired functions effectively.

Procedures have been developed and implemented to guide the rigid body of crank driven four-bar linkages, through a set of design positions with techniques to avoid their defects. However, the practical applications of linkages used in the industry are coupler driven, with primitive synthesis procedures based on trial and error. The opening and closing of the hood …

A Study Of The Numerical Implementation Of Multidisciplinary Design Optimization Strategies, Rodney A. Taylor

Mechanical & Aerospace Engineering Theses & Dissertations

Design optimization provides an organized, systematic, and efficient method for obtaining design improvements based upon a specified measure of design performance. In the multidisciplinary design optimization (MDO) environment efficient optimization techniques allow complex designs to be improved by managing conflicting disciplinary design goals so as to improve the global design. This thesis studies the implementation issues surrounding MDO techniques and strategies. To facilitate this investigation two testbed problems have been selected for study. These problems consider two approaches to the conceptual design of an aeroelastic wing. The first approach is based on an idealized, two-dimensional representation of an airfoil under …

Visual Speech Recognition Using Multiple Deformable Lip Models, Devi Chandramohan

Electrical & Computer Engineering Theses & Dissertations

Motivated by the fact that human speech perception is a bimodal process (auditory and visual), several researchers have designed and implemented automatic speech recognition (ASR) systems consisting of both audio and visual subsystems, and shown improved performance relative to traditional purely auditory systems. Several visual speech reading approaches have used deformable templates to model the shape of a speaker's lips. Deformable templates are models of image objects, which can be deformed by adjusting a set of parameters to match the object in some optimal way, as defined by a cost function. Using a single deformable lip model has disadvantages such …

Neural Generalized Predictive Control For Real-Time Control, Donald I. Soloway

Electrical & Computer Engineering Theses & Dissertations

In this thesis a computationally efficient Generalized Predictive Control (GPC) algorithm is presented and implemented. The algorithm is more efficient than others because the number of iterations needed for convergence is significantly lower with Newton-Raphson. The main additional cost with Newton-Raphson algorithm is the calculation of the Hessian. This overhead is not a problem because of the reduced number of iterations, making the algorithm suitable for real-time control. For nonlinear control applications, a neural network is used as a dynamical system predictor leading to a Neural Generalized Predictive Control (NGPC) algorithm which is presented in detail in this thesis. An …

An Investigation Of The Influence Of Tightening Torque And Sea Water On Pultruded Gfrp Composite Bolted Joints, Satish Devara

Mechanical & Aerospace Engineering Theses & Dissertations

Pultruded glass fiber-reinforced polymeric matrix composites are candidate materials for ever-increasing structural applications due to their continuous production capability, light weight and excellent properties. In this investigation an extensive experimental study has been carried out to understand their structure, basic mechanical properties, and influence of fiber orientation on the unnotched, notched and pin-loaded tensile strength. Furthermore, the effects of sea water and tightening torque separately and together on the failure loads and failure modes of the bolted joints are also studied. It is shown that blockshear failure mode is also a principal mode of failure in the bolted joints of …

Effects Of Elevated Temperature On The Physical Aging Of A High Temperature Thermoplastic Resin And Composite, Mark Feldman

Mechanical & Aerospace Engineering Theses & Dissertations

Development of a High Speed Civil Transport is considered by the commercial aviation industry to be one of the next big challenges for our national aircraft industry. Critical to the success of this aircraft is the development of advanced polymeric composites for both the primary and secondary structures and the predictive methodology necessary for assessment of long term durability. While polymeric composites offer an excellent strength to weight ratio a key disadvantage is the time dependent properties exhibited by the polymer matrix which can age and ultimately effect the resultant stiffness of a laminate.

Experimental studies were performed to determine …

The Corporate Effects Of R&D And Patent-Grants: Evidence From Intra-Industry Analysis, Steven Alan Lifland

Theses and Dissertations in Business Administration

This study examines the intra-industry effect of announcements of technological advancement on the market valuation of both the announcing firm and the announcing firm's relative industry competitors. This paper consists of two parts. Essay I discusses firm specific and intra-industry valuation effects of a firm's Research and Development (R&D) expenditures, while Essay II concentrates on the firm-specific and intra-industry valuation effects of a firm's patent-grant announcement. Specifically, this study examines the validity of the competitive and free-rider hypotheses to explain the market response to announcements of R&D spending and the granting of patents.

While the evidence shows that the market …

Exploring Knowledge Processes For Technology Assimilation, Rochelle K. Young

Engineering Management & Systems Engineering Theses & Dissertations

In the emerging knowledge society, the ability to make the experience and expertise of those involved in and affected by new technology unconditionally available to all members of an organization is becoming increasingly important. One of the problems in developing such knowledge processes for technology assimilation is that current social structures do not easily accommodate unconditional participation. Since the implementation of modern information technology is changing the workplace and the nature of work itself, alternative social structures are needed. This research takes as given that deep questions concerning knowledge processes and social transformation are in principle undecidable; and, only questions …

Long-Term Effects Of Seawalls On The Adjacent Nonwalled Beaches Of A Historically Receding Shoreline, Bryan Norton Jones

Civil & Environmental Engineering Theses & Dissertations

Great debate has arisen in recent years over the effects seawalls may or may not have on the erosion rate of a historically receding shoreline. A primary obstacle to the formation of definite conclusions about this subject is the lack of long-term physical data, which must be collected prior to and following seawall construction. This thesis presents the results of a study using 15 years of beach profile data to determine how seawalls influence the existing erosional trends of the beach at Sandbridge, Virginia.

Three analysis methods using three time scales (historic, seasonal, and storms) were used to answer three …

A Progressive Damage Methodology For Residual Strength Predictions Of Center-Crack Tension Composite Panels, Timothy William Coats

Mechanical & Aerospace Engineering Theses & Dissertations

An investigation of translaminate fracture and a progressive damage methodology was conducted to evaluate and develop residual strength prediction capability for laminated composites with through penetration notches. This is relevant to the damage tolerance of an aircraft fuselage that might suffer an in-flight accident such as an uncontained engine failure. An experimental characterization of several composite materials systems revealed an R-curve type of behavior. Fractographic examinations led to the postulate that this crack growth resistance could be due to fiber bridging, defined here as fractured fibers of one ply bridged by intact fibers of an adjacent ply.

The progressive damage …

Scalability In Real-Time Systems, Ramesh Yerraballi

Computer Science Theses & Dissertations

The number and complexity of applications that run in real-time environments have posed demanding requirements on the part of the real-time system designer. It has now become important to accommodate the application complexity at early stages of the design cycle. Further, the stringent demands to guarantee task deadlines (particularly in a hard real-time environment, which is the assumed environment in this thesis) have motivated both practioners and researchers to look at ways to analyze systems prior to run-time. This thesis reports a new perspective to analyzing real-time systems that in addition to ascertaining the ability of a system to meet …

A Test Of An Alternate Calibration Matrix For Niosh Method 7300, Robert T. Vitek

Community & Environmental Health Theses & Dissertations

The purpose of this study was to determine if the analytical results (when determining cadmium, lead, and zinc concentrations) for air sample filters prepared and analyzed according to N:OSH Method 7300, differ significantly, from those obtained when the instrument is calibrated using EPA Method 200.7 acid matrix standards. The null hypothesis was that no statistically significant difference, measured at the 95% confidence level, would exist between results obtained from the two calibration standards. Careful standard and sample preparation, the use of an internal standard, and the application of working standard and working internal standard correction factors served to isolate the …