Engineering Commons^™

Plasma Actuator, Jamey D. Jacob

Mechanical Engineering Faculty Patents

An actuator including a first and second conductor on a dielectric, wherein application of a voltage to the first conductor creates a plasma, thereby modifying a fluid flow in communication with the actuator. Related systems and methods are also provided.

Simulation Of Nanowire Tunneling Transistors: From The Wentzel-Kramers-Brillouin Approximation To Full-Band Phonon-Assisted Tunneling, Mathieu Luisier, Gerhard Klimeck

Birck and NCN Publications

Nanowire band-to-band tunneling field-effect transistors 􏰀TFETs􏰁 are simulated using the Wentzel– Kramers–Brillouin 􏰀WKB􏰁 approximation and an atomistic, full-band quantum transport solver including direct and phonon-assisted tunneling 􏰀PAT􏰁. It is found that the WKB approximation properly works if one single imaginary path connecting the valence band 􏰀VB􏰁 and the conduction band 􏰀CB􏰁 dominates the tunneling process as in direct band gap semiconductors. However, PAT is essential in Si and Ge nanowire TFETs where multiple, tightly-coupled, imaginary paths exist between the VB and the CB. © 2010 American Institute of Physics. 􏰂doi:10.1063/1.3386521􏰃

Huygens’ Box Methodology For Signal Integrity Analysis, Lijun Jiang, J. D. Morsey, B. J. Rubin, W. C. Chew, M. K. Li, Y. Liu

Electrical and Computer Engineering Faculty Research & Creative Works

A method for performing a signal integrity analysis on an integrated circuit (IC) that includes a plurality of scatterers by dividing the scatterers into subgroups using a nested Huygens' equivalence principal algorithm and solving a set of equations realized thereby with a reduced coupling matrix. The method includes decomposing the IC design into a plurality of small non-overlapping circuit sub-domains, wherein each of the sub-domains is formed as a small, enclosed region. Each sub-domain is analyzed independently of the other sub-domains using only electric fields to represent the interactions of each sub-domains with the other sub-domains as equivalent currents on …

2010 - The Fifteenth Annual Symposium Of Student Scholars

Symposium of Student Scholars Program Books

The full program book from the Fifteenth Annual Symposium of Student Scholars, held on April 27, 2010. Includes abstracts from the presentations and posters.

Design And Feasibility Testing For A Ground-Based, Three-Dimensional, Ultra-High-Resolution, Synthetic Aperture Radar To Image Snowpacks, Stephen Joseph Preston

Theses and Dissertations

This thesis works through the design of a radar-based system for imaging snowpacks remotely and over large areas to assist in avalanche prediction. The key to such a system is the ability to image volumes of snow at shallow, spatially-varying angles of incidence. To achieve this prerequisite, the design calls for a ground-based Synthetic Aperture Radar (SAR) capable of generating three-dimensional, ultra-high-resolution images of a snowpack. To arrive at design parameters for this SAR, the thesis works through relevant principles in avalanche mechanics, alpine-snowpack geophysics, and electromagnetic scattering theory. The thesis also works through principles of radar, SAR, antenna, and …

Mineralization Potential Of Electrospun Pdo-Nha-Fibrinogen Scaffolds Intended For Cleft Palate Repair, Isaac Rodriguez

Theses and Dissertations

The overall goal of this study was to identify mineralized scaffolds which can serve as potential alternatives to bone graft substitutes intended for cleft palate repair. The aim of this preliminary study was to evaluate the role of fibrinogen (Fg) and nano-hydroxyapatite (nHA) in enhancing mineralization potential of polydioxanone (PDO) electrospun scaffolds. Scaffolds were fabricated by blending PDO:nHA:Fg in the following weight ratios: 100:0:0, 50:25:25, 50:50:0, 50:0:50, 0:0:100 and 0:50:50. Scaffolds were immersed in different simulated body fluids for 5 and 14 days to induce mineralization. The inclusion of fibrinogen induced sheet-like mineralization while individual fiber mineralization was noticed in …

Ghost Estates Will Haunt Us For Years, Lorcan Sirr

Media

No abstract provided.

Women In The Aviation Industry, Maureen N. Mutisya

Senior Honors Theses

The Aviation industry has developed extensively since its establishment by the Wright Brothers in 1903. Over time, the highly male-dominated industry experienced significant changes to incorporate female aviators. Determined women initiated this process through participating in the aircraft engineering sector and pursuing careers as pilots. However, these women faced various challenges, which resulted in setbacks to their effective growth in the industry. In fact, vital issues encountered in the past are still present and often overlooked in today’s aviation industry. Therefore, identifying these problems and proposing solutions with effective corrective measures is necessary to increase and motivate female pilots globally.

Chaos-Assisted Directional Light Emission From Microcavity Lasers, Susumu Shinohara, Takahisa Harayama, Takehiro Fukushima, Martina Hentschel, Takahiko Sasaki, Evgenii Narimanov

Birck and NCN Publications

We study the effect of dynamical tunneling on emission from ray-chaotic microcavities by introducing a suitably designed deformed disk cavity. We focus on its high quality factor modes strongly localized along a stable periodic ray orbit confined by total internal reflection. It is shown that dominant emission originates from the tunneling from the periodic ray orbit to chaotic ones; the latter eventually escape from the cavity refractively, resulting in directional emission that is unexpected from the geometry of the periodic orbit, but fully explained by unstable manifolds of chaotic ray dynamics. Experimentally performing selective excitation of those modes, we succeeded …

Electrophysiological Analysis In An Animal Model Of Dystonia, Kunal Chaniary

Theses and Dissertations

Dystonia is a movement disorder characterized by patterned, repetitive, and sustained muscle contractions that cause ineffective and often painful movements. The overall goal of this project was to understand the physiological mechanisms of dystonia in a rodent model as a basis for developing innovative treatments for secondary dystonias. The first half of the project was focused at developing essential techniques for systematically investigating the movement disorder in these animals. For achieving this, an innovative, multi-faceted approach was pursued starting with electromyographic (EMG) analysis for animal model validation, gait analysis for dystonia quantification, and development of a novel stereotaxic apparatus for …

Particle Image Velocimetry Measurements Of The Total Cavopulmonary Connection With Circulatory Flow Augmentation, Steven Chopski

Theses and Dissertations

This thesis project examined the interactive fluid dynamics between a blood pump and the univentricular Fontan circulation. 2-D particle image velocimetry (PIV) measurements were conducted on an idealized total cavopulmonary connection (TCPC) with an axial pump prototype in the inferior vena cava (IVC). Fluid velocity profiles were examined under various physiologic conditions for Fontan patients. The velocity profiles for all cases demonstrated the shunting of flow from the IVC toward the right pulmonary artery. A rotational component in the pump outflow was observed forcing flow to the periphery as compared to the flow profile without a pump present in the …

Newsletter 41 Issue 1 - Spring 2010 - Nuts And Bolts, Larsen Tractor Museum

Friends of the Larsen Tractor Museum

No abstract provided.

Using Buckling-Restrained Braces In Eccentric Configurations, Gary S. Prinz

Theses and Dissertations

Ductile braced frames are often used to resist lateral earthquake loads in steel buildings; however the presence of a brace element can sometimes interfere with architectural features. One common type of ductile braced frame system sometimes used to accommodate architectural features is the eccentrically braced frame (EBF). In order to dissipate seismic forces, EBF beam regions (called links) must sustain large inelastic deformations. EBF links with column connections must transmit large moments and shear forces to facilitate link rotation. Experiments have shown that welded link-to-column connections tend to fracture in the link flange prior to large link rotations. This study …

Development Of Mechanical Cardiovascular Assist Devices For Fontan Patients: Two Novel Approaches, Sonya Bhavsar

Theses and Dissertations

Few therapeutic alternatives exist for patients with a failing single ventricle physiology. To address this need, this thesis project investigated two new therapeutic alternatives, which sought to positively augment the Fontan hemodynamics. The first modality introduced a non-invasive method of external pressure application to the lower extremities. A clinical study (n=2) was conducted, and results indicated an increase in flow as a consequence to an increase in transmural pressure in the lower extremities. The second modality investigated a minimally invasive blood pump. Numerical analyses of the pump were performed to examine hydraulic performance under physiologic conditions. The pump produced pressure …

Summary Of Feedback Edge Set Papers, Jonathan Johnson

Faculty Publications

The problem of finding a set of edges F from a directed graph G = (V,E) such that the graph G0 = (V,E − F) contains no cycles is known as the feedback edge set (FES) problem or the feedback arc set problem. A related problem is the minimum feedback edge set problem, in which the feedback edge set F must be minimal. The feedback edge set problem has application in applying a common reliability technique called triple modular redundancy to FPGA circuit designs where configuration memory scrubbing is employed [1].

Novel Techniques For The Integration Of Antennas And Photovoltaic Cells, Maria Roo Ons, S. Shynu, Max Ammann, Sarah Mccormack, Brian Norton

Conference Papers

Various novel approaches to the integration of antenna and photovoltaic technologies are proposed. These include the use of polycrystalline solar cells as groundplane for microstrip patch antennas as well as for reflectors of half-wave dipole antennas. Transparent materials were also evaluated as antenna radiating elements, allowing greater solar efficiency. A novel technique illustrating how emitter-wrap-through rear contact solar cells can be used as a folded-dipole antenna, which is located in the focal line of a parabolic solar concentrator, to provide high solar efficiency as well as high antenna gain, is presented.

Maintenance Optimization For Substations With Aging Equipment, Haifeng Ge

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Today’s electric utilities are confronted with a myriad of challenges that include aging infrastructure, enhanced expectation of reliability, reduced cost, and coping effectively with uncertainties and changing regulation requirements. Utilities rely on Asset Management programs to manage inspections and maintenance activities in order to control equipment conditions. However, development of strategies to make sound decisions in order to effectively improve equipment and system reliability while meeting constraints such as a maintenance budget is a challenge.

The primary objective of this dissertation is to develop models and algorithms to study the impact of maintenance toward equipment/system reliability and economic cost, and …

Ceas E-News 04.20.2010, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

WMU wins second overall in ASCE event

Site Design Of A Four-Story 11,705 Sq-Ft Class A Office Building, Britney Richmond, Allison Porrett, Kimberly Warners

Honors Theses

This senior capstone design project was a two-semester long venture that began last fall with the formation of the team, the selection of the sponsored project, and the conclusion of a proposal. The purpose of the proposal was for the senior design team to display a thorough understanding of the project's scope of work and to declare the deliverables agreed upon by the team. The team began contact with the sponsor, Hurley &Stewart, prior to beginning the proposal writing in order to gain more details about the project at hand and to ask any questions. The team chose to add …

A Computer Vision Application To Accurately Estimate Object Distance, Kayton B. Parekh

Mathematics, Statistics, and Computer Science Honors Projects

Scientists have been working to create robots that perform manual work for years. However, creating machines that can navigate themselves and respond to their environment has proven to be difficult. One integral task to such research is to estimate the position of objects in the robot's visual field.

In this project we examine an implementation of computer vision depth perception. Our application uses color-based object tracking combined with model-based pose estimation to estimate the depth of specific objects in the view of our Pioneer 2 and Power Wheels robots. We use the Camshift algorithm for color-based object tracking, which uses …

A Design Framework That Employs A Classification Scheme And Library For Compliant Mechanism Design, Brian Mark Olsen

Theses and Dissertations

Limited resources are currently available to assist engineers in implementing compliant members into mechanical designs. As a result, engineers often have little to no direction incorporating compliant mechanisms. This thesis develops a conceptual design framework and process that utilizes a proposed classification scheme and a library of mechanisms to help engineers incorporate compliant mechanisms into their applications. As the knowledge related to the synthesis and analysis of compliant mechanisms continues to grow and mature, and through the classification scheme established in this thesis, compliant mechanisms may become more extensively used in commercial mechanical designs. This thesis also demonstrates a design …

Optimization And Evaluation Of A Proportional Derivative Controller For Planar Arm Movement, Kathleen M. Jagodnik, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

In most clinical applications of functional electrical stimulation (FES), the timing and amplitude of electrical stimuli have been controlled by open-loop pattern generators. The control of upper extremity reaching movements, however, will require feedback control to achieve the required precision. Here we present three controllers using proportional derivative (PD) feedback to stimulate six arm muscles, using two joint angle sensors. Controllers were first optimized and then evaluated on a computational arm model that includes musculoskeletal dynamics. Feedback gains were optimized by minimizing a weighted sum of position errors and muscle forces. Generalizability of the controllers was evaluated by performing movements …

Optimality Principles For Model-Based Prediction Of Human Gait, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient's gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like …

Development Of Criteria For Lamina Emergent Mechanism Flexures With Specific Application To Metals, Devin Bradley Ferrell

Theses and Dissertations

This thesis introduces new revolute and torsional lamina emergent mechanism (LEM) flexure designs that are suited for use in metals. Previous LEM flexures have been designed for use in highly elastic materials, such as polymers. In extending LEM flexure designs to metals, a LEM flexure design criteria is also introduced. The LEM flexure criteria is based on relative performance between the LEM flexure and a performance datum which the LEM flexure must improve upon. This performance datum, or benchmark, is a section of lamina that is of the same overall length, width, and thickness as the LEM flexure. An analysis …

A Proposed Learner-Centered Mechatronics Engineering Instructional Program, Patrick N. Currier, Richard Goff, Janis Terpenny

Mechanical Engineering - Daytona Beach

This paper examines the need and requirements for a mechatronics degree program. The results of a survey of the few existing programs in this field are provided. Then, using a case study example for Virginia Tech, a proposed mechatronics curriculum based on a learner-centered paradigm is described. The curriculum combines existing courses in mechanical, electrical, and computer engineering with new, hands-on courses to provide students with a chance to practice and explore the subject matter in ways consistent with the demands of both industry and accreditation. This program, if implemented, could provide a university with a unique offering to attract …

Rapport: Semantic-Sensitive Namespace Management In Large-Scale File Systems, Yu Hua, Hong Jiang, Yifeng Zhu, Dan Feng

School of Computing: Technical Reports

Explosive growth in volume and complexity of data exacerbates the key challenge to effectively and efficiently manage data in a way that fundamentally improves the ease and efficacy of their use. Existing large-scale file systems rely on hierarchically structured namespace that leads to severe performance bottlenecks and renders it impossible to support real-time queries on multi-dimensional attributes. This paper proposes a novel semantic-sensitive scheme, called Rapport, to provide dynamic and adaptive namespace management and support complex queries. The basic idea is to build files’ namespace by utilizing their semantic correlation and exploiting dynamic evolution of attributes to support namespace management. …

Synthesis Of An Endothelial Cell Mimicking Surface Containing Thrombomodulin And Endothelial Protein C Receptor, Karl E. Kador

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Synthetic materials for use in blood contacting applications have been studied for many years with limited success. One of the main areas of need for these materials is the design of synthetic vascular grafts for use in the hundreds of thousands of patients who have coronary artery bypass grafting, many without suitable veins for autologous grafts. The design of these grafts is constrained by two common modes of failure, the formation of intimal hyperplasia (IH) and thrombosis. IH formation has been previously linked to a mismatching of the mechanical properties of the graft and has been overcome by creating grafts …

Gain Error Correction For Cmos Image Sensor Using Delta-Sigma Modulation, Kuangming Yap, R. Jacob Baker

Electrical and Computer Engineering Faculty Publications and Presentations

A delta-sigma modulation analog-to-digital converter (ADC) has many benefits over the use of a pipeline ADC in a CMOS image sensor. This includes lower power, noise reduction, ease of maximizing the input range, and simpler signal routing for large arrays. Multiple delta-sigma modulation ADC is required in a CMOS image sensor, one for each pixel column. Any voltage threshold mismatch between ADCs will introduce gain and offset error in its transfer function, which will lead to fix pattern noise. Correcting these gain and offset error for every ADCs in the image sensor will require a complex digital signal processor. Therefore, …

Main Memory With Proximity Communication: A Wide I/O Dram Architecture, Qawi Harvard, R. Jacob Baker, Robert Drost

Electrical and Computer Engineering Faculty Publications and Presentations

The bandwidth and power consumption of dynamic random access memory (DRAM), used as the main memory of a computer system, impacts computer execution rates. DRAM manufacturers focus on density increases, due to the innate price per bit decline of main memory, while processor manufacturers continually focus on boosting performance. This leads to a performance gap between the two technologies. Proximity communication promises to increase the off/on chip bandwidth of DRAM products while reducing the power consumption of the main memory system. The design of a memory system employing 4 Gb DRAM chips with a 64-bit wide communication bus using proximity …

Channel Characterization For Wireless Underground Sensor Networks, Agnelo Rocha Da Silva

School of Computing: Dissertations, Theses, and Student Research

Wireless Underground Sensor Networks (WUSNs) are natural extensions of the established Wireless Sensor Network (WSN) phenomenon and consist of sensors buried underground which communicate through soil. WUSNs have the potential to impact a wide variety of applications including precision agriculture, environmental monitoring, border patrol, and infrastructure monitoring. The main difference between WUSNs and traditional wireless networks is the communication medium. However, a comprehensive wireless underground channel model for WUSNs has not been developed so far. In this thesis, the Soil Subsurface Wireless Communication (SSWC) channel model is developed based on an extensive empirical study in a large agriculture field. The …