Engineering Commons^™

Solvent Dependent Morphologies In Thiol-Ene Photopolymerization: A Facile Route To Synthesis Of Resorcinarene Nanocapsules, Zaharoula Marie Kalaitzis

Chemistry & Biochemistry Theses & Dissertations

Synthesis of morphologically distinct polymeric nanostructures is vital for their wide ranging applications from nanomedicine to material science. Among various polymeric nanostructures, nanocapsules in particular have attracted a lot of attention as nanoreactors and drug delivery vehicles in nanomedicine. Often, synthesis of nanocapsules is achieved by template-based approaches. A direct, template-free method for the fabrication of nanocapsules and a variety of other morphologically distinct polymeric architectures was developed. The photopolymerization of a resorcinarene thiol-ene surfactant in various solvents lead to the formation of nanocapsules, nanoparticles, fibers, distorted honeycomb-like lattices, and sheets. The progress of the polymerization reaction and the morphology …

Effects Of Non-Equilibrium Plasma On Eukaryotic Cells (Final Report: Grant Fa9550-06-1-0004), Mounir Laroussi, Fred C. Dobbs, Old Dominion University

Electrical & Computer Engineering Faculty Publications

This document is our final report describing the research activities carried out under AFOSR Grant FA9550-06-1-0004. First, descriptions of our cold plasma generation systems are presented. Two systems, developed with past and present AFOSR support, are available in our laboratory. The first is a pulsed device capable of emitting a cold plasma plume in room air. The second is an air plasma generator the core of which is a dielectric barrier discharge excited by a high AC voltage. Following these brief descriptions we first present the effects of an atmospheric pressure air plasma on four different types of eukaryotic microalgae. …

Section Abstracts: Aeronautical And Aerospace Sciences

Virginia Journal of Science

Abstracts of the Aeronautical and Aerospace Sciences Section for the 87th Annual Meeting of the Virginia Academy of Science, May 27-29, 2009, Virginia Commonwealth University, Richmond, Virginia.

Section Abstracts: Astronomy, Mathematics, And Physics & Materials Science

Virginia Journal of Science

Abstracts of the Astronomy, Mathematics and Physics & Materials Science Section for the 87th Annual Meeting of the Virginia Academy of Science, May 27-29, 2009, Virginia Commonwealth University, Richmond VA.

Effects Of Low-Temperature Atmospheric Pressure Plasma On Streptococcus Mutans, Margaret Farrer Lemaster

Dental Hygiene Theses & Dissertations

The recent emergence of low temperature atmospheric pressure plasma (LTAPP) technology has led researchers to explore biomedical applications. The present study set out to determine if LTAPP has the ability to inactivate dental caries causing bacteria, specifically Streptococcus mutans. Methods: A total of 90 samples were processed. Seventy-two samples of S. mutans at 1: 100 dilution in BHI broth were exposed to LTAPP for various time intervals (60, 120, 180, 300 seconds). Eighteen control samples were plated but not exposed to LTAPP. Samples were plated on Mi tis salivarius (MS) agar and incubated 48 hours at 37° C. Colony …

Developing A Philosophical Profile Of The Individual For Complex Problem-Solving Through Agent-Based Modeling, Ipek Bozkurt

Engineering Management & Systems Engineering Theses & Dissertations

Research that focuses on the emotional, mental, behavioral and cognitive capabilities of individuals has been abundant within disciplines such as psychology, sociology, and anthropology, among others. The main argument made in this dissertation, however, is that a different perspective is necessary in order to gain insight about individuals when facing the complex problems that are presented within engineering and management disciplines. This is done by developing the Philosophical Profile of the Individual (PPI) that uses epistemology, ontology and teleology as underlying dimensions of philosophical predispositions. The epistemology dimension considers whether an individual is an Empiricist or a Rationalist, the ontology …

A Study Of Decision Analysis Methods In Aerospace Technology Assessments, Sharon Monica Jones

Engineering Management & Systems Engineering Theses & Dissertations

Managers of aerospace technology programs and projects are faced with the challenge of making technology portfolio decisions under conditions of limited data, rapidly changing macro level factors and organizational uncertainties. To help make these technology investment decisions, some aerospace managers and analysts have used techniques from the field of decision analysis. In addition, there have been a limited number of research studies of real decision problems.

This dissertation presents the results of a non-experimental examination of the use of decision analysis methods for the assessment of aerospace technology portfolios. A web-based survey instrument was developed based on the results of …

Reconciling Discontinuities And Disruptions: The Construction Of An Integrated Typology, David Jeffery Kern

Engineering Management & Systems Engineering Theses & Dissertations

Radical innovations are often characterized by a rapid shift from one dominant design to another. The theories of discontinuous and disruptive innovation present two important and independent explanations for why these shifts occur. This research tests the usefulness of combining these two theories into a single integrated typology. First, a typology is constructed that classifies shifts in dominant designs according to the theories of discontinuous and disruptive innovation. Next, the usefulness of this typology is tested with a taxonomy derived from 100 randomly selected shifts in dominant designs from across a broad range of industries. This research reconciles the theories …

Surface Dynamics Of Silicon Low-Index Surfaces Studied By Reflection High-Energy Electron Diffraction, Ibrahim El-Kholy

Electrical & Computer Engineering Theses & Dissertations

Surface morphology during the growth of Si on Si(111)-(7x7) by femtosecond pulsed laser deposition (fsPLD) is studied using reflection high-energy electron diffraction (RHEED) at different temperatures. The growth of Si on Si(111) has received considerable attention as a model system of homoepitaxy. PLD is a deposition technique that uses much more energetic species (atoms and ions) compared to other physical vapor deposition (PVD), such as in molecular beam epitaxy. In this work, in situ reflection high energy electron diffraction (RHEED) was used to study the dynamics of PLD of Si on Si(111)-(7x7). Epitaxial growth of Si/Si(111)-(7x7) at temperatures as low …

Numerical/Experimental Investigation Of Plunge Stage And Effect Of Donor Material In Friction Stir Welding, Saptarshi Mandal

Mechanical & Aerospace Engineering Theses & Dissertations

Friction Stir Welding (FSW) was developed in 1991 as a robust solid-state joining technique that uses a specially shaped rotating tool to generate heat and plasticize material around the tool. The tool then mixes plasticized material along the joint line to produce the weld. Over the last decade, FSW has become increasingly popular for welding aluminum. The combination of attractive properties of the weld and cost-efficiency has led researchers to investigate the feasibility of using FSW for steel. One of the major impediments for using friction stir welding for harder materials such as steel is tool wear. It is well-documented …

3d Numerical Modeling Of Hydrodynamic Flow, Sediment Deposition And Transport In Stormwater Ponds And Alluvial Channels, Leying Zhang

Civil & Environmental Engineering Theses & Dissertations

Prediction of flow and sediment transport is an important and challenging problem for stormwater management and river engineering applications. This thesis concerns primarily the computation of flow, sediment deposition and transport processes in stormwater ponds and alluvial channels based on a multiphase flow approach in modeling sediment transport. Starting from an existing hydrodynamic Reynolds Averaged Navier-Stokes flow solver, numerical models are developed to predict flow, sediment deposition and transport under the FLUENT software package. Two types of sediment transport models are formulated to consider quantities of present sediment phase volume fractions: a Discrete Phase Model in a Lagrangian frame where …

Prostate Cancer Biomarker Identification: A Comparative Study, Wenjuan Jiang

Computational Modeling & Simulation Engineering Theses & Dissertations

With the current development of proteomics techniques, the discovery of potential molecular biomarkers for early detection of prostate cancer has been greatly improved. In this thesis, we implemented five classifiers including the support vector machine (SVM), Bayesian Classifier, Decision Tree, Random Forest and the Multilayer perceptron (MLP) to test their effectiveness in prostate cancer biomarker identification using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) tissue imaging data. The classifiers were utilized to discriminate cancer mass spectra from normal ones for the data collected at the Eastern Virginia Medical School (EVMS). There are 94 7 spectra from normal tissues and 27 from …

Towards The Efficient Probabilistic Characterization Of Tropical Cyclone-Generated Storm Surge Hazards Under Stationary And Nonstationary Conditions, Senanu Kudjo Agbley

Civil & Environmental Engineering Theses & Dissertations

The scarcity of observations at any single location confounds the probabilistic characterization of tropical cyclone-generated storm surge hazards using annual maxima and peaks-over-threshold methods. The EST and the JPM are indirect approaches aimed at estimating the probability distribution of the response variable of interest (i.e. storm surge) using the probability distributions of predictor variables (e.g. storm size, storm intensity etc.). In the first part of this work, the relative performance of the empirical simulation technique (EST; Borgman et al., 1992) and the joint probability method (JPM; Myers, 1970) is evaluated via stochastic simulation methods. It is shown that the JPM …

Using Geographically Weighted Regression Models To Analyze Crash Harm, Libin Zheng

Civil & Environmental Engineering Theses & Dissertations

Society pays a high cost for collisions in terms of property damage, injuries and loss of life. This paper has two objectives. One is to examine various factors associated with harm caused by highway collisions. Both global OLS and local GWR models are provided to identify specific variables influencing crash harm. Another objective is to demonstrate the use of a Geographically Weighted Regression (GWR) method in this complex safety problem, which can estimate models for each crash location and show spatial variation. The results show that the GWR model is a significant improvement on the OLS model; the test for …

Time Valuation Of Risk A Delayed-Bang Approach, Abhishek Pathak

Engineering Management & Systems Engineering Theses & Dissertations

The subject of this thesis is the combined use of engineering economics and survival analysis in estimating time-value of risk-related resources. The discussion includes (1) the need for sustainable risk management, (2) the importance of time-valuation of risk related resources in the allocation or selection among competing risk mitigation alternatives, (3) the convergence of deterministic engineering economics, survivability analysis, and probabilistic analysis, and (4) results and examples of application in the context of prevention of risk event or mitigation of its consequences.

The significance of this thesis is in how three topics: engineering economics, survivability analysis, and probability theory can …

Stability Analysis, Modeling, Simulation And Experimental Testing Of An Ems Maglev System With Structural Flexibility, Aravind M. Hanasoge

Mechanical & Aerospace Engineering Theses & Dissertations

Vehicle-guideway interaction studies of Magnetically Levitated (Maglev) vehicles indicate that structural flexibility can adversely affect the overall stability and performance of such systems. This is one of the reasons why guideways are generally made very rigid. This in turn leads to increased cost of the overall system since guideway construction forms a significant portion of the overall cost. In this dissertation, the influence of structural flexibility on the stability of Electromagnetic Suspension (EMS) Maglev systems is studied. It is shown how inherently unstable and flexible structure EMS Maglev systems can achieve guaranteed stability by using collocated actuators and sensors, along …

An Analytical Framework And Model Formulation For Measuring Risk In Engineering Enterprise Systems: A Capability Portfolio Perspective, Paul Raphael Garvey

Engineering Management & Systems Engineering Theses & Dissertations

This work formulates an analytical framework and computational model for assessing risk in engineering enterprise systems. It addresses the engineering management problem of how to represent, model, and measure risk in large-scale, complex systems engineered to function in enterprise-wide environments.

The research in this dissertation extends current practice in the management of risk for traditional systems and creates new constructs and protocols for the management of risk in engineering large-scale, complex, and highly networked enterprise systems. This work advances engineering management theory and analytic practice as applied to the measurement and management of risk for enterprise systems engineered within capability …

Compensation Of Loss And Stimulated Emission Of Surface Plasmon Polaritons, Guohua Zhu

Electrical & Computer Engineering Theses & Dissertations

Surface plasmon polaritons (SPPs) have become in recent years an important research topic because of their interesting, physics and exciting potential applications, ranging from sensing and biomedicine to nanoscopic imaging and information technology. However, many applications of surface plasmon polaritons are hindered by one common cause—absorption loss in metal.

Over the years, numerous proposals have been made on how to conquer the plasmon loss. In this dissertation, (1) the known solutions to the loss problem by adding optical gain have been reviewed; (2) the properties of surface plasmon polaritons are studied theoretically, and the solution of the controversy regarding the …

Geometrically Nonlinear Arc Length Sparse Finite Element Analysis And Optimal Design Of Truss Structures, Glenn A. Hrinda

Civil & Environmental Engineering Theses & Dissertations

A technique for the optimization of stability-constrained geometrically nonlinear shallow trusses with snap-through behavior is demonstrated using the arc length method and a strain energy density approach within a discrete finite element formulation. The optimization method uses an iterative scheme that evaluates the performance of the design variables and then updates them according to a recursive formula that is controlled by the arc length method. A minimum weight design is achieved when a uniform nonlinear strain energy density is found in all members. This minimal condition places the design load just below the critical-limit load that causes snap-through of the …

Using Timed-Release Cryptography To Mitigate The Preservation Risk Of Embargo Periods, Rabia Haq, Michael L. Nelson

Computer Science Presentations

PDF of a powerpoint presentation from the 2009 ACM/IEEE Joint Conference on Digital Libraries, Austin, Texas, June 15-19, 2009. Also available on Slideshare.

Adding Escience Assets To The Data Web, Herbert H. Van De Sompel, Carl Lagoze, Michael L. Nelson, Simeon Warner, Robert Sanderson, Pete Johnston

Computer Science Faculty Publications

Aggregations of Web resources are increasingly important in scholarship as it adopts new methods that are data-centric, collaborative, and networked-based. The same notion of aggregations of resources is common to the mashed-up, socially networked information environment of Web 2.0. We present a mechanism to identify and describe aggregations of Web resources that has resulted from the Open Archives Initiative - Object Reuse and Exchange (OAI-ORE) project. The OAI-ORE specifications are based on the principles of the Architecture of the World Wide Web, the Semantic Web, and the Linked Data effort. Therefore, their incorporation into the cyberinfrastructure that supports eScholarship will …

Towards The Quantitative Analysis Of The Connectivity Value Of Networked Operations, Dean Deller

Engineering Management & Systems Engineering Theses & Dissertations

While the nature of and the approach to command and control is evolving in order to meet the challenges of Information Age warfare, the essential functions that must be accomplished remain constant. One of those essential functions is the arrangement of the assets within a combat force. Certainly, the many different ways to arrange a given set of assets will have different impacts on the combat effectiveness of the force. Some arrangements will enable self-synchronization, while other arrangements will impede it. How then, should an Information Age combat force be organized in order to optimize its effectiveness?

The concept of …

Investigating The Relationship Between An It Project Manager's Emotional Intelligence And The Customer's Perception Of Success, William Jacob Lamarsh Ii

Engineering Management & Systems Engineering Theses & Dissertations

This research focuses on the intersections of Project Management, Information Technology (IT), and Emotional Intelligence. The Project Management Institute (PMI) created the Project Management Professional (PMP) certification, which is one of the most highly regarded and sought after professional certifications (Project Management Institute 2005, p. 15-18). This certification acknowledges the holder as a knowledgeable practitioner in Project Management. The purpose behind Project Management is to obtain requirements, sometimes fluid at best, and develop solutions that are traceable by schedule and cost controls. This approach allows a Project Manager to monitor and control the project through successful completion. However, the PMI …

Network Optimization Of Dynamically Complex Systems, Ramez Ahmed Shamseldin

Engineering Management & Systems Engineering Theses & Dissertations

The aim of this research is to optimize large scale network handling capabilities for large system inventories and to implement strategies for the purpose of reducing capital expenses. As computers become more and more networked, it is easier to share files among storage media. In addition, more bandwidth will be consumed by network flow because customers will be connected through networks which will transfer files and data, such as video files (MPEGn, AVI, WMV, etc.) to be watched at a customer's computer (host). Furthermore, these networks terminals will be used as mini warehouses to save files and data. Selective files …

On The Role Of Assertions For Conceptual Modeling As Enablers Of Composable Simulation Solutions, Robert Dennis King

Computational Modeling & Simulation Engineering Theses & Dissertations

This research provides a much needed systematic review of the roles that assertions play in model composability and simulation interoperability. In doing so, this research contributes a partial solution to one of the problems of model composability and simulation interoperability—namely, why do simulation systems fail to achieve the maximum level of interoperability possible? It demonstrates the importance of the assertions that are made during model development and simulation implementation, particularly as they reflect the unique viewpoint of each developer or user. It hypothesizes that it is possible to detect composability conflicts by means of a four-step process developed by the …

Mitigating Crack Propagation In A Highly Maneuverable Flight Vehicle Using Life Extending Control Logic, Mohamed Mostafa Yousef Bassyouny Elshabasy

Mechanical & Aerospace Engineering Theses & Dissertations

In this research, life extending control logic is proposed to reduce the cost of treating the aging problem of military aircraft structures and to avoid catastrophic failures and fatal accidents due to undetected cracks in the airframe components. The life extending control logic is based on load tailoring to facilitate a desired stress sequence that prolongs the structural life of the cracked airframe components by exploiting certain nonlinear crack retardation phenomena. The load is tailored to include infrequent injections of a single-cycle overload or a single-cycle overload and underload. These irregular loadings have an anti-intuitive but beneficial effect, which has …

Spatiotemporal Estuarine Water Quality Parameterization Using Remote Sensing And In-Situ Characteristics, Kwisun Park Yu

Civil & Environmental Engineering Theses & Dissertations

This dissertation develops a new paradigm in a water quality monitoring approach to parameterize spatiotemporal estuarine water quality with sustainable reliability, less cost and less time. A key underpinning of this paradigm of the spatiotemporal estuarine water quality parameterization is various water quality parameters' interrelationship with ambient water temperature as a common factor, their time dependent characteristics, and spatiotemporal characteristics of remote sensing. It has two core models to provide input data of water quality parameterization model in a system; the transfer function models of the physical system and an analytical temperature time series model. The objective of this dissertation …

Operational Knowledge Transfer In Municipal Utility Organizations, G. Christian Guvemator Iv

Engineering Management & Systems Engineering Theses & Dissertations

Municipal water and wastewater utility systems experience several challenges related to maintaining an experienced operations workforce. One of these issues is the loss of operational knowledge as the current experienced workforce reaches the age of retirement. The future success of system operability depends upon a process that transfers the knowledge of the experienced employee into the organization before he or she retires. Recent investigations highlight the importance of, and the methods for, knowledge transfer; however, current literature does not include significant information on the municipal utility industry. The objective of this investigation is to identify how operational knowledge is being …

Characterization Of Microwave Cavity Discharges In A Supersonic Flow, Dareth Janette Drake

Physics Theses & Dissertations

A partially ionized gas is referred to as either a plasma or a discharge depending on the degree of ionization. The term discharge is usually applied to a weakly ionized gas, i.e. mostly neutrals, where as a plasma usually has a larger degree of ionization. To characterize a discharge the plasma parameters, such as the rotational temperature, vibrational temperature, and electron density, must be determined. Detailed characterization of supersonic flowing discharges is important to many applications in aerospace and aerodynamics. One application is the use of plasma-assisted hydrogen combustion devices to aid in supersonic combustion. In conditions close to the …

Multidisciplinary Design Optimization For Sonic Boom Mitigation, Isik A. Ozcer

Mechanical & Aerospace Engineering Theses & Dissertations

Automated, parallelized, time-efficient surface definition and grid generation and flow simulation methods are developed for sharp and accurate sonic boom signal computation in three dimensions in the near and mid-field of an aircraft using Euler/Full-Potential unstructured/structured computational fluid dynamics. The full-potential mid-field sonic boom prediction code is an accurate and efficient solver featuring automated grid generation, grid adaptation and shock fitting, and parallel processing. This program quickly marches the solution using a single nonlinear equation for large distances that cannot be covered with Euler solvers due to large memory and long computational time requirements. The solver takes into account variations …