Engineering Commons^™

Negative Dielectrophoretic Capture Of Bacterial Spores In Food Matrices, Mehti Koklu, Seungkyung Park, Suresh D. Pillai, Ali Beskok

Mechanical & Aerospace Engineering Faculty Publications

A microfluidic device with planar square electrodes is developed for capturing particles from high conductivity media using negative dielectrophoresis (n-DEP). Specifically, Bacillus subtilis and Clostridium sporogenes spores, and polystyrene particles are tested in NaCl solution (0.05 and 0.225 S/m), apple juice (0.225 S/m), and milk (0.525 S/m). Depending on the conductivity of the medium, the Joule heating produces electrothermal flow (ETF), which continuously circulates and transports the particles to the DEP capture sites. Combination of the ETF and n-DEP results in different particle capture efficiencies as a function of the conductivity. Utilizing 20 μm height DEP chambers, “almost complete” and …

A Study Of Passive Earth Pressure In Anisotropic Sand With Various Wall Movement Modes, Achmad Bakri Muhiddin

Civil & Environmental Engineering Theses & Dissertations

This study investigated the effect of anisotropy on passive pressure in sands by developing computer simulation utilizing FLAC code for plane strain condition. A series of wall movement modes was applied namely translation, rotation about a point below the wall, RBT, and rotation about a point above the wall, RTT.

From comparisons with other FLAC model in translation mode with isotropic material, the coefficients of passive pressure K_p were similar to each other except for some combinations of zero dilation, low wall friction, and high angle of internal friction ϕ. Dilation angle has less effect on K_p than …

A Predictive Game Theoretic Model To Assess Us - Russian Response To An Islamic Safe-Haven In The Caucasus Region, Christopher Wayne Hartline

Computational Modeling & Simulation Engineering Theses & Dissertations

The thesis examines possible US and Russian policy decisions following the establishment of an Islamist safe-haven in Chechnya. Conflicting national policies affect the possibility of a negotiated settlement. Domestic and international political considerations constrain the decision-making of the two nations. The author applies game theory to examine the sequential decision-making of the two nations. The extensive form model draws outcome payoff values from a bounded uniform distribution. This approach naturally models uncertainty; and, it allows repeated probabilistic instantiations of the model. These instantiations produce a range of solutions. The most likely outcome was a negotiated settlement, generally following a tit-for-tat …

The Effect Of Systematic Error In Forced Oscillation Wind Tunnel Test Apparatuses On Determining Nonlinear Unsteady Aerodynamic Stability Derivatives, Brianne Y. Williams

Mechanical & Aerospace Engineering Theses & Dissertations

One of the basic problems of flight dynamics is the formulation of aerodynamic forces and moments acting on an aircraft in arbitrary motion. Classically conventional stability derivatives are used for the representation of aerodynamic loads in the aircraft equations of motion. However, for modern aircraft with highly nonlinear and unsteady aerodynamic characteristics undergoing maneuvers at high angle of attack and/or angular rates the conventional stability derivative model is no longer valid. Attempts to formulate aerodynamic model equations with unsteady terms are based on several different wind tunnel techniques: for example, captive, wind tunnel single degree-of-freedom, and wind tunnel free-flying techniques. …

Experimental Investigation Of A Non-Thermal Atmospheric Pressure Plasma Jet, Asma Begum

Electrical & Computer Engineering Theses & Dissertations

The main objective of this dissertation is to understand the formation of the plasma jet from the plasma pencil, and the propagation of the plasma jet in the ambient atmosphere where the effect of the external electric field is almost zero. Before investigating the formation and propagation phenomenon of the plasma jet, common physical properties of plasma jets are determined by using the imaging technique and optical emission spectroscopy. The first goal of this dissertation is to establish the laminar helium gas flow channel through a plasma pencil.

The formation position, formation time, and the criterion of the plasma jet …

The Executable Command In Support Of Scheduled Subroutine Calls, Andrew Scott Lewis

Electrical & Computer Engineering Theses & Dissertations

A potential solution to improving the utilization of increased thread level parallelism available in modern general purpose CPU's is the inclusion of a hardware scheduler. The hardware scheduler is designed to schedule subroutine calls based on a numerical condition in a high performance memory located on the CPU die, due to which the size of available memory is extremely limited. The main stumbling block in the development of a feasible hardware scheduler is the lack of a method of invoking a scheduled call using a single pointer. The use of a single pointer allows the limited size of the memory …

A Neighborhood Dependent Nonlinear Technique For Enhancement Of Color Images Captured Under Non-Uniform Lighting Conditions, Rupal Patel

Electrical & Computer Engineering Theses & Dissertations

The aim of image enhancement process is to improve the interpretability of the information in images for human viewers or to provide better input for automated image processing techniques. Many image processing applications begin with a nonlinear enhancement process to improve visual quality of video sequences captured under nonuniform lighting conditions. This improves the visibility of the scene captured from physical sensing devices which have limited dynamic range. This physical limitation causes the saturated region of the image to either shadow out or wash out the rest of the scene. When extremely bright and dark regions are present in an …

Using Micro-Simulation To Evaluate Transit Signal Priority For Lrt Operations In A Downtown Environment, Faisal Mahmud

Civil & Environmental Engineering Theses & Dissertations

Transit Signal Priority or TSP is an operational strategy that facilitates the movement of transit vehicles such as buses, light rail or streetcars, through traffic-signal controlled intersections. The benefits of TSP operations include improved schedule adherence and improved transit travel times with minimal impact to normal traffic operations. New advances in Global Positioning Systems, detection and communication, and control strategies have helped overcome many problems with early systems and increased interest in implementing TSP for Light Rail Transit (LRT) and other transit operations. The increased capabilities of these advanced systems have led to a dramatic increase in operational and planned …

Wavelet-Based Enhancement Technique For Visibility Improvement Of Digital Images, Numan ÜNaldı

Electrical & Computer Engineering Theses & Dissertations

Image enhancement techniques for visibility improvement of color digital images based on wavelet transform domain are investigated in this dissertation research.

In this research, a novel, fast and robust wavelet-based dynamic range compression and local contrast enhancement (WDRC) algorithm to improve the visibility of digital images captured under non-uniform lighting conditions has been developed. A wavelet transform is mainly used for dimensionality reduction such that a dynamic range compression with local contrast enhancement algorithm is applied only to the approximation coefficients which are obtained by low-pass filtering and down-sampling the original intensity image. The normalized approximation coefficients are transformed using …

A Differential Absorption Model For Remote Sensing Of Atmospheric Pressure, Shivam J. Shah

Electrical & Computer Engineering Theses & Dissertations

The goal of the project is to develop and test a "model based" radar processing strategy that is compatible with the concept of a "cognitive radar". The basic approach will be to develop a cognitive radar algorithm (genetic algorithm) based on the capabilities of an existing commercially available Software Radio. While the focus of this effort is the development of a candidate approach for genetic algorithm, the longer term goal would be to implement the approach using this software radio technology to provide a low cost radar processor. The proposed technology would use differential absorption radar working at the 50-56 …

Post-Project Risk Perception And Systems Management Reaction, Baqer Alali

Engineering Management & Systems Engineering Theses & Dissertations

The objective of this research is to identify whether risk management in projects has any role in risk management in systems. Projects, systems, and risk management are three integral concepts in the management of various enterprises and agencies. Risk management is a common concept in systems and project processes. To avoid failures or crisis during their life cycles, projects and systems managers practice risk management. Projects and systems have well defined life cycles during which the risk is defined, controlled, and managed. Risk management is conducted in each phase of projects and systems. Projects are initiated to close certain operational …

Repeating Ground Track Design For Low Earth Orbit Satellite, Gurkan Gurdal

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, conditions and design requirements for a repeating ground track for a low Earth orbit satellite have been examined and several repeating ground tracks have been designed for a single area on the Earth. In order to construct and validate desired orbital results, the study has two phases which also help to investigate repeating ground track conditions: the fist one is the design phase, and second one is the simulation phase. The common objective of all the case studies is to present a closed ground track on the target by using the design parameters. In order to design …

Simulation Of Temperature Distributions In Tissue Upon Laser Pulse Irradiation Including Water Mass Transfer, Deepthi Nagulapally

Electrical & Computer Engineering Theses & Dissertations

Lasers, due to their unique characteristics, have tremendous applications in the medical field. Generally all laser applications in hie-medicine involve the propagation of laser energy through tissue. Energy is deposited giving rise to many physical, hie-chemical, and mechanical effects. Among these are dynamical changes in the local temperature distributions within the tissue. Analysis of the temperature changes requires the creation of an appropriate optical transmission and heat flow model that incorporates user specified laser parameters. Here, a numerical simulation model was developed to study both steady state and time dependent temperature distributions due to pulsed laser radiation within user specified …

Analytic Construction Of Periodic Orbits In The Restricted Three-Body Problem, Mohammed A. Ghazy

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation explores the analytical solution properties surrounding a nominal periodic orbit in two different planes, the plane of motion of the two primaries and a plane perpendicular to the line joining the two primaries, in the circular restricted three-body problem. Assuming motion can be maintained in the plane and motion of the third body is circular, Jacobi's integral equation can be analytically integrated, yielding a closed-form expression for the period and path expressed with elliptic integral and elliptic function theory. In this case, the third body traverses a circular path with nonuniform speed. In a strict sense, the in-plane …

Simulation Studies Of Pulsed Voltage Effects On Cells, Jiahui Song

Electrical & Computer Engineering Theses & Dissertations

This dissertation research focuses on the new field of pulsed electric field interactions with biological cells. In particular, "Intracellular Electromanipulation" which has important biomedical applications, is probed. Among the various aspects studied, nanosecond, high-intensity pulse induced electroporation is one phenomena. It is simulated based on a coupled scheme involving the current continuity and Smoluchowski equations. A dynamic pore model can be achieved by including a dependence on the pore population density and a variable membrane tension. These changes make the pore formation energy E(r) self-adjusting and dynamic in response to pore formation. Additionally, molecular dynamics (MD) simulations are also discussed …

Nanoindentation Creep Analysis For A Spherical Indenter, Phani K. Praturi

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this work is to determine the strain rate sensitivity of the hardness in indentation creep and to investigate the relationship between the strain rate sensitivity of the hardness vH and the strain rate sensitivity of the flow stress vCT. A finite element model of nanoindentation creep was constructed and a parametric analysis was performed using Abaqus/Standard analysis software. It is found that the ratio vH / vCT does not maintain a unique relation with HIE• and varies with the increase in the ratio of depth of penetration to the radius of the indenter a/ R . Simulations …

Simultaneous Higher Harmonic Detection And Extraction Of Information From Oxygen Spectra, Karan Dineshchandra Mohan

Electrical & Computer Engineering Theses & Dissertations

Wavelength Modulation Spectroscopy (WMS) is a highly sensitive technique that utilizes synchronous detection at the N-th harmonics of a modulating frequency, by modulating the laser beam used to probe a gaseous species. The advantage of this technique lies in the greater effective signal-to-noise ratio one obtains as a direct consequence of the larger amount of structure present in the higher harmonics, and thus a greater amount of information that can be obtained from that structure. We present the development of a novel technique where data at multiple harmonics is obtained simultaneously, rather than sequentially. This removes the susceptibility of the …

Action Recognition Based On Multi-Level Representation Of 3d Shape, Binu M. Nair

Electrical & Computer Engineering Theses & Dissertations

A novel algorithm is proposed in this thesis for recognizing human actions using a combination of two shape descriptors, one of which is a 3D Euclidean distance transform and the other based on the Radon transform. This combination captures the necessary variations from the space time shape for recognizing actions. The space time shapes are created by the concatenation of human body silhouettes across time. The comparisons are done against some common shape descriptors such as the zernike moments and Radon transform. This is also compared with an algorithm which uses the same concept of a space time shape and …

The Influence Of Network Factors On Network Centric Operations, Mehmet Fidanci

Engineering Management & Systems Engineering Theses & Dissertations

As Information Age changes the lifestyle of all humankinds, it also changes the way how to defense and secure the borders are secured and defended. The Information Age is about information superiority. It evolves the command and control concept, proactively, to optimize the size of the units and their connections within a combat force for effective mission accomplishment. The biggest issue is how big a unit will be and how they will arrange and connect it to the command and control structure in order for the unit to be effective on the battlefield. While some arrangements connect to each other …

Multi-Scale Edge Detection Algorithms And Their Information-Theoretic Analysis In The Context Of Visual Communication, Bo Jiang

Electrical & Computer Engineering Theses & Dissertations

The unrealistic assumption that noise can be modeled as independent, additive and uniform can lead to problems when edge detection methods are applied to low signal-to-noise ratio (SNR) images. The main reason for this is because the filter scale and the threshold for the gradient are difficult to determine at a regional or local scale when the noise estimate is on a global scale. Therefore, in this dissertation, we attempt to solve these problems by using more than one filter to detect the edges and discarding the global thresholding method in the edge discrimination. The proposed multi-scale edge detection algorithms …

Analysis And Optimization Of Dynamic Spectrum Sharing For Cognitive Radio Networks, Manish Wadhwa

Electrical & Computer Engineering Theses & Dissertations

The goal of this dissertation is to present the analysis and optimization of dynamic spectrum sharing for cognitive radio networks (CRNs). Spectrum scarcity is a well known problem at present. In order to deal with this problem, dynamic spectrum sharing (DSS) was proposed. DSS is a technique where cognitive radio networks dynamically and opportunistically share the channels with primary users. The major contribution of this dissertation is in analyzing the problem of dynamic spectrum sharing under different scenarios and developing optimal solutions for these scenarios. In the first scenario, a contention based dynamic spectrum sharing model is considered and its …

Dielectrophoretic Separation Of Mouse Melanoma Clones, Ahmet C. Sabuncu, Jie A. Liu, Stephen J. Beebe, Ali Beskok

Bioelectrics Publications

Dielectrophoresis (DEP) is employed to differentiate clones of mouse melanoma B16F10 cells. Five clones were tested on microelectrodes. At a specific excitation frequency, clone 1 showed a different DEP response than the other four. Growth rate, melanin content, recovery from cryopreservation, and in vitro invasive studies were performed. Clone 1 is shown to have significantly different melanin content and recovery rate from cryopreservation. This paper reports the ability of DEP to differentiate between two malignant cells of the same origin. Different DEP responses of the two clones could be linked to their melanin content.

Modified Sequential Kriging Optimization For Multidisciplinary Complex Product Simulation, Wang Hao, Wang Shaoping, Mileta M. Tomovic

Engineering Technology Faculty Publications

Directing to the high cost of computer simulation optimization problem, Kriging surrogate model is widely used to decrease the computation time. Since the sequential Kriging optimization is time consuming, this article extends the expected improvement and put forwards a modified sequential Kriging optimization (MSKO). This method changes the twice optimization problem into once by adding more than one point at the same time. Before re-fitting the Kriging model, the new sample points are verified to ensure that they do not overlap the previous one and the distance between two sample points is not too small. This article presents the double …

Section Abstracts: Aeronautical And Aerospace Sciences

Virginia Journal of Science

Abstracts of the Aeronautical and Aerospace Science Section for the 88th Annual Meeting of the Virginia Academy of Science, May 20-21, 2010, James Madison University, Harrisonburg, VA.

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

Virginia Journal of Science

Abstracts of papers of the Astronomy, Mathematics, and Physics (Including Materials Science) Section for the 88th Annual Meeting of the Virginia Academy of Science, May 20-21, 2010, James Madison University, Harrisonburg, VA.

Section Abstracts: Biomedical And General Engineering

Virginia Journal of Science

Abstracts of the Biomedical and General Engineering Section for the 88th Annual Meeting of the Virginia Academy of Science, May 20-21, 2010, James Madison University, Harrisonburg, VA.

Hybrid Intelligent Optimization Methods For Engineering Problems, Yasin Volkan Pehlivanoglu

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of optimization is to obtain the best solution under certain conditions. There are numerous optimization methods because different problems need different solution methodologies; therefore, it is difficult to construct patterns. Also mathematical modeling of a natural phenomenon is almost based on differentials. Differential equations are constructed with relative increments among the factors related to yield. Therefore, the gradients of these increments are essential to search the yield space. However, the landscape of yield is not a simple one and mostly multi-modal. Another issue is differentiability. Engineering design problems are usually nonlinear and they sometimes exhibit discontinuous derivatives for …

A Decision Making Construct For Complex Situations, Van Edward Brewer

Engineering Management & Systems Engineering Theses & Dissertations

The uncertainty inherently associated with complexity challenges decision-making processes, indicating a need for a construct for decision making in complex situations. A review of the literature on systems, complexity, and paradigms indicates that such a construct must be internally consistent with well-defined philosophical foundations and further that systems and complexity (as used in complex situations) are not necessarily internally consistent with traditional philosophical foundations. Therefore, a decision making construct for complex situations requires research into different foundations. This research addresses these gaps, deriving axiological and methodological components based on a set of principles consistent with the ontology and epistemology of …

Providing Location Security In Vehicular Ad Hoc Networks, Gongjun Yan

Computer Science Theses & Dissertations

Location is fundamental information in Vehicular Ad-hoc Networks (VANETs). Almost all VANET applications rely on location information. Therefore it is of importance to ensure location information integrity, meaning that location information is original (from the generator), correct (not bogus or fabricated) and unmodified (value not changed). We present validation mechanisms to provide location integrity for VANETs. In the initial mechanism, we assume that all vehicles are equipped with a radar, a GPS receiver, and a transceiver. Since radar has a limited radar range and transceiver has a limited transmission range, we build network cells as a security unit as well …

A Genetic Algorithm Approach For Optimized Routing, Pavithra Gudur

Electrical & Computer Engineering Theses & Dissertations

Genetic Algorithms find several applications in a variety of fields, such as engineering, management, finance, chemistry, scheduling, data mining and so on, where optimization plays a key role. This technique represents a numerical optimization technique that is modeled after the natural process of selection based on the Darwinian principle of evolution. The Genetic Algorithm (GA) is one among several optimization techniques and attempts to obtain the desired solution by generating a set of possible candidate solutions or populations. These populations are then compared and the best solutions from the set are retained. Subsequently, new candidate solutions are produced, and the …