Engineering Commons^™

Cascaded Multilevel Converters With Non-Integer Or Dynamically Changing Dc Voltage Ratios, Shuai Lu, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

Multilevel converters made of cascaded cells (MCCC) offer a high number of voltage levels with a given switch count. Many variants of the MCCC topology have been introduced over years. Mostly, only integer DC voltage ratios between the cascaded converter cells have been applied to its PWM modulation. This is mainly due to the non-uniform distribution of voltage vectors with the non-integer DC ratios. It poses difficulty to the conventional SVM modulators relying on locating the equilateral "triangle" made of three nearest vectors enclosing the reference vector. In this paper, an original modulation method is introduced to operate with any …

Predicting Tem Cell Measurements From Near Field Scan Data, Haixiao Weng, Daryl G. Beetner, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

A procedure is proposed for predicting TEM cell measurements from near field scans by modeling near-field scan data using equivalent sources. The first step in this procedure is to measure the tangential electric and magnetic fields over the circuit. Electric and magnetic fields are estimated from probe measurements by compensating for the characteristics of the probe. An equivalent magnetic and electric current model representing emissions is then generated from the compensated fields. These equivalent sources are used as an impressed source in an analytical formula or full wave simulation to predict measurements within the TEM cell. Experimental verification of the …

Signal Link-Path Characterization Up To 20 Ghz Based On A Stripline Structure, Jianmin Zhang, James L. Drewniak, David Pommerenke, Richard E. Dubroff, Zhiping Yang, Wheling Cheng, John C. Fisher, Sergio Camerlo

Electrical and Computer Engineering Faculty Research & Creative Works

Dielectric properties and losses are two critical issues in signal link-path characterization. To obtain the substrate dielectric properties for a planar transmission line, an analytical solution is derived and validated based on a stripline structure and measured scattering parameters with TRL de-embedding. The characterized dielectric property is used to evaluate dielectric loss and conductor loss. The total loss is thereby found from their summation. The calculated total loss is compared to the measured total loss, and the conductor loss and dielectric loss are then quantifiable. Since the conventional description using the loss tangent and dielectric constant to represent material properties …

Influence Of An Extended Stub At Connector Ports On Signal Launches And Trl De-Embedding, Jianmin Zhang, James L. Drewniak, David Pommerenke, Bruce Archambeault, Zhiping Yang, Wheling Cheng, John Fisher, Sergio Camerlo

Electrical and Computer Engineering Faculty Research & Creative Works

Characterization of PCBs (Printed Circuit Boards) is usually associated with measurement using a VNA (Vector Network Analyzer) in the frequency-domain or a TDR (Time Domain Reflectometer) in the time-domain. The often used signal launch techniques on PCBs based on the VNA or TDR measurement in the microwave frequency range use SMA or 3.5 mm connectors, in edge-launch or vertical-launch fashions. The signal transition between the launch port and the DUT (Device Under Test) introduces errors in the measurement, which is dominant when compared with a transmission line itself on the PCB as the technologies of PCB manufacturing well developed today. …

Development Of Three Block Thermal Compact Model And Verification Of Modified Linear Superposition Technique For Stacked Die, Suresh G. Nikalaje

Mechanical and Aerospace Engineering Theses - Archive

Over the last few years an impressive amount of progress has been achieved in the field of compact modeling of chip packages. But available compact modeling methods could not address the issue of limitation on the mesh statistics which is major concern while modeling in FEM softwares with limited number of nodes and elements. It is not possible to attain convergence of solution for thermal simulation of detailed model with the constraint on the number of nodes and elements. In this thesis, a simple and straight forward three block (3B) compact modeling method is developed. 3B compact modeling method has …

Investigation Of Bamboo As Reinforcement In Concrete, Youngsi Jung

Civil Engineering Theses - Archive

This study investigated the feasibility of using bamboo as a reinforcement alternative to steel in concrete structural members. The specifications studied were the bamboo's tensile strength and its pullout characteristics in concrete. Two types of bamboo, Solid and Moso, were used for tensile testing. The tensile test specimens were prepared with different lengths, 6 in (152 mm) and 12 in (304 mm), and different physical characteristics (with and without nodes). Tensile test specimens were tested to failure and their load deformation characteristics are reported. The failures of the test specimens were identified as: (1) node failure; (2) splitting failure; and …

Novel Preparation Of Polymeric Scaffolds For Tissue Engineering Using Phase Separation With Protein Microbubble Incorporation, Ashwin Nair

Bioengineering Theses - Archive

Poly (lactic-co-glycolic acid) (PLGA) has been extensively used as a biodegradable and porous tissue scaffold due to their biocompatibility and degradability. Several techniques have been developed for the fabrication of polymeric scaffolds but they all have some limitation or the other which has in turn hampered the growth of cells seeded on them. Salt leached scaffolds have good porosity and large pores but poor mechanical strength and the problem of residual salt even after leaching. Similarly gas foaming scaffolds have shown large pores but poor interconnection with residual ammonium salts. Other methods like thermally induced phase separation and fiber bonding …

Use Of Near Infrared And Visible Spectroscopies To Determine Optical Properties Of Rat Nervous System, Harsha Radhakrishnan

Bioengineering Theses - Archive

Changes to the anatomical or physiological structure of the neuronal circuitry are known to produce a change in the optical properties of the tissue under investigation. The goal of this thesis is to determine changes in the light scattering and hemoglobin oxygen saturation in three cases: (i) a normal spinal cord, (ii) demyelinated sciatic nerve, and (iii) spinal cord under neuronal activity induced by peripheral electrical stimulation. We hypothesize that (i) nerve demyelination or degeneration would result in a decrease in light scattering and hemoglobin oxygen saturation and (ii) peripheral electrical stimulation would show an increase in light scattering and …

Moving A Part-Time Engineering Course To A Student-Centred Paradigm, Kevin Kelly

Conference papers

This paper is a further reflection on two conference papers presented at the World Conference for Continuing Engineering Education (WCCEE) in Vienna in April 2006 and National University of Ireland (NUI) Galway Conference: The Challenge of Diversity: Teaching, Support and Student Learning , June 2006. Both conference papers dealt with different aspects of my experiences of the theoretical and pedagogical changes required in re-design and delivery of a part-time engineering programme for the continuing education development of electrical engineers in the workforce.

The Application Of Learning Skills In An Engineering Programme, Leslie Shoemaker

Conference papers

At the Dublin Institute of Technology, an engineering programme in the School of Control Systems and Electrical Engineering has successfully incorporated a study skills module into the core curriculum. The module, titled Academic Development and Key Skills, is part of the first year of the programme and has a two-fold purpose. Primarily the goal is to assist the students with the transition from second level education to third level by teaching them a more competent learning style. This, in turn, helps to create a positive impact with respect to the retention of this student group within the programme. The second …

Engineering Of Ferrite-Graphite Composite Media For Microwave Shields, Marina Koledintseva, Poorna Chander Ravva, James L. Drewniak, Alexander A. Kitaytsev, Andrey A. Shinkov

Electrical and Computer Engineering Faculty Research & Creative Works

An electromagnetic shielding of objects using ferrite-graphite composites is considered. The analytical model, using the Maxwell Garnett formulation for multiphase mixtures, results of computations based on this model and plane-wave formulation, and some experimental results are represented.

A Method For Charactering Emi Coupling Paths And Source Properties In Complex Systems, Shishuang Sun, Gang Feng, Chong Ding, David Pommerenke, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A method for charactering EMI coupling paths in complex systems is presented. While it is relatively easy to determine the EMI antenna structures or the sources of EMI, it is often quite difficult to identify, and even more difficult to quantify coupling paths. This paper introduces a measurement-based method to quantify EMI coupling paths, and the source strengths can be indirectly determined by applying linear system theory. Circuit design guidelines, e.g., the permissible even-mode current in a differential signal, can be derived with the knowledge of the coupling path and EMI limits. Moreover, the EMI can be better predicted with …

Comparison Of X-Ray, Millimeter Wave, Shearography And Through-Transmission Ultrasonic Methods For Inspection Of Honeycomb Composites, Mohamed A. Abou-Khousa, Adam C. Ryley, Sergey Kharkovsky, R. Zoughi, David J. Daniels, Nicholas A. Kreitinger, Gary J. Steffes

Electrical and Computer Engineering Faculty Research & Creative Works

Honeycomb composites are increasingly finding utility in a variety of environments and applications, such as aircraft structural components, flight control components, radomes, etc. In-service and environmental stresses can produce unwanted flaws that adversely affect the structural integrity and functionality of these composites. These flaws may be in the forms of disbonds, delaminations, impact damage, crushed honeycomb, moisture intrusion, internal cracks, etc. There are several nondestructive testing (NDT) methods that may be used to inspect these composites for the presence and evaluation of these flaws. Such NDT methods include X-ray computed tomography, near-field millimeter wave, shearography, and ultrasonic testing. To assess …

Optimal Statcom Sizing And Placement Using Particle Swarm Optimization, J. C. Hernandez, Ganesh K. Venayagamoorthy, Yamille Del Valle, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Heuristic approaches are traditionally applied to find the size and location of Flexible AC Transmission Systems (FACTS) devices in a small power system. Nevertheless, more sophisticated methods are required for placing them in a large power network. Recently, the Particle Swarm Optimization (PSO) technique has been applied to solve power engineering optimization problems giving better results than classical methods. This paper shows the application of PSO for optimal sizing and allocation of a Static Compensator (STATCOM) in a power system. A 45 bus system (part of the Brazilian power network) is used as an example to illustrate the technique. Results …

An Alternative Target Density Function For Radar Imaging, Askin Demirkol, Levent Acar, Robert S. Woodley, Erol Emre

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an alternative Target Density Function (TDF) is proposed to image the radar targets in a dense target environment. It is produced by wavelet theory considering a new range and angle plane different from the conventional methods. It is shown that Wavelet theory can be used as approach to imaging by active sensors by transmitting a waveform which is a kernel for this transform such as a window function. Although the imaging is obtained via the phased array radars, the problem associated with beamforming in linear phased array radar system is bypassed in this new algorithm.

Sign Retroreflectivity: Fiscal Impact Of Proposed Minimum Retroreflectivity Values On Local Governments In Indiana And Investigation Of Accuracy Of Nighttime Inspections, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

To remain effective, traffic signs need to be clearly legible to all motorists. Their retroreflectivity is an important factor in their legibility. Recently, the Federal Highway Administration (FHWA) has proposed a set of minimum retroreflectivity values to which all signs shall conform. The purpose of this study was two fold; to investigate the fiscal impact of these proposed minimums on roadways managed by counties, cities, and towns within in the State of Indiana and compare the accuracy of a simple nighttime inspection method to the more labor intensive measured retroreflectivity method.

Estimates performed on the collected data suggest that the …

2006 Statewide Bridge Sufficiency Rating Report, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

The main purpose of this report is to provide bridge sufficiency rating information for the bridges in each county. This information results from the data generated by the National Bridge Inspection Standards (NBIS) program authorized by the 1968 Federal Aid Highway Act.

Design And Manufacturing Of Functionally Graded Materials With Polymer Chain And Nano-Reinforcement Orientation For Compressive Applications, Sanjay Varma Kalidindi

Theses and Dissertations - UTB/UTPA

Functionally Graded Materials for compressive applications were designed and manufactured by tailoring the properties of Pure Polyethylene (PE) and Vapor Grown Carbon Nanofiber (VGCNF) Reinforced PE Composites. Properties of NRPC have been extensively studied. Properties are dependent on parameters such as the reinforcement/matrix interaction; reinforcement volume fraction, orientation, dispersion, and packing, and the final matrix microstructure. However, there is limited literature on their properties under compression loading. Compression strength studies for high density PE reinforced with VGCNF for different fiber volume fraction (0%, 5%, 10% and 15%) were carried out. The role of interface and alignment was studied. Samples were …

Electrorheology Of Fullerene Suspensions, Maricela Lizcano

Theses and Dissertations - UTB/UTPA

Electrorheological fluids are suspension materials whose rheological behavior changes with an applied voltage. In particular, the material changes from a fluid to a solid behavior with an applied voltage and reverses to its original state when the voltage is removed. This function classifies ER fluids as smart materials. ER fluids may be developed and used as mechanical devices with no mechanical parts such as pumps, actuators, and dampers. Until recently, research was concentrated with micro-particle suspension fluids. This research project investigates the electrorheology of carbon nano-particle suspension.

Vegetative Treatment Systems For Open Lot Runoff: Review Of Literature, Richard K. Koelsch, Jeffrey Lorimer, Kyle Mankin

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Runoff from open lot livestock systems (beef and dairy) defined as Concentrated Animal Feeding Operations (CAFO) must be controlled by systems designed and managed to prevent the release of manure-contaminated runoff for storms equal to or less than a 25-year, 24-hour design storm. This performance standard has been attained for open lot systems with some combination of clean water diversion, settling basins, runoff collection ponds and irrigation systems (baseline system).

An alternative approach is to rely on overland flow and infiltration into cropland with perennial forage or grasses for treatment of open lot runoff. Such vegetative systems have been researched …

Uncertainty Quantification Of Satellite Precipitation Estimation And Monte Carlo Assessment Of The Error Propagation Into Hydrologic Response, Hamid Moradkhani, Yang Hong, Soroosh Sorooshian

Civil and Environmental Engineering Faculty Publications and Presentations

The aim of this paper is to foster the development of an end-to-end uncertainty analysis framework that can quantify satellite-based precipitation estimation error characteristics and to assess the influence of the error propagation into hydrological simulation. First, the error associated with the satellite-based precipitation estimates is assumed as a nonlinear function of rainfall space-time integration scale, rain intensity, and sampling frequency. Parameters of this function are determined by using high-resolution satellite-based precipitation estimates and gauge-corrected radar rainfall data over the southwestern United States. Parameter sensitivity analysis at 16 selected 5ø ? 5ø latitude-longitude grids shows about 12?16% of variance of …

Viscoelastic Flow In Rotating Curved Pipes, Yitung Chen, Huajun Chen, Jinsuo Zhang, Benzhao Zhang

Mechanical Engineering Faculty Research

Fully developed viscoelastic flows in rotating curved pipes with circular cross section are investigated theoretically and numerically employing the Oldroyd-B fluid model. Based on Dean’s approximation, a perturbation solution up to the secondary order is obtained. The governing equations are also solved numerically by the finite volume method. The theoretical and numerical solutions agree with each other very well. The results indicate that the rotation, as well as the curvature and elasticity, plays an important role in affecting the friction factor, the secondary flow pattern and intensity. The co-rotation enhances effects of curvature and elasticity on the secondary flow. For …

Cross-Layer Issues In Mac Protocol Design For Mimo Ad Hoc Networks, Michael A. Jensen, A. Lee Swindlehurst, Michele Zorzi, James R. Zeidler, Adam L. Anderson, Bhaskar Rao, John Proakis, Srikanth Krishnamurthy

Faculty Publications

In this article, we discuss research and design issues that arise in the development of networking protocols for an ad hoc network where nodes are equipped with multiple antenna elements and have the ability to perform signal processing operations as required by adaptive beamforming, interference cancellation, and space-time coding.

99mTc-Labeled C2a Domain Of Synaptotagmin I As A Target-Specific Molecular Probe For Noninvasive Imaging Of Acute Myocardial Infarction, Ming Zhao, Xiaoguang Zhu, Shundong Ji, Jundong Zhou, Kutlan S. Ozker, Wei Fang, Robert C. Molthen, Robert S. Hellman

Biomedical Engineering Faculty Research and Publications

Abstract: The exposure of phosphatidylserine (PtdS) is a common molecular marker for both apoptosis and necrosis and enables the simultaneous detection of these distinct modes of cell death. Our aim was to develop a radiotracer based on the PtdS-binding activity of the C2A domain of synaptotagmin I and assess ^99mTc-C2A-GST (GST is glutathione S-transferase) using a reperfused acute myocardial infarction (AMI) rat model. Methods: The binding of C2A-GST toward apoptosis and necrosis was validated in vitro. After labeling with ^99mTc via 2-iminothiolane thiolation, radiochemical purity and radiostability were tested. Pharmacokinetics and biodistribution were studied in healthy rats. …

Preliminary Modeling, Control, And Trajectory Design For Miniature Autonomous Tailsitters, Nathan B. Knoebel, Stephen R. Osborne, Deryl Snyder, Timothy W. Mclain, Randal W. Beard, Andrew Mark Eldredge

Faculty Publications

A tailsitter UAV has unique advantages over typical fixed wing aircraft or hovercraft. This paper highlights topics of interest in our preliminary research in developing a tailsitter UAV. An aerodynamic model and quaternion-based attitude and position control scheme is presented for controlling a tailsitter through hover maneuvers, with simulation results. Desired trajectories are also developed through feedback linearization of the dynamic equations, intended for quaternion-based attitude control. Finally, a hardware platform is proposed.

The Effects Of Paper Physical Properties On Print Gloss And Ink Mileage, Renmei Xu

Dissertations

Ink film coat weight was measured using an internal tracer method. Commercial toluene based gravure inks were marked with the tracer, which can be detected analytically and used to calculate ink film coat weight. The ink film coat weight versus relative print density data was plotted and curve fitting was performed using six previous proposed models. The models that were used to fit laboratory results were also found useful for pilot plant press results. Oittinen model and Calabro-Savagnone model fitted the experimental data better than the other four models, measured by the sum of the square of residuals and their …

Investigation Of The Performance Of The New Orleans Flood Protection System In Hurricane Katrina On August 29, 2005: Volume 1, Raymond B. Seed, Robert G. Bea, Remon I. Abdelmalak, Adda G. Athanasopoulos, Gordon P. Boutwell, Jr., Jonathan D. Bray, Jean-Louis Briaud, Carmen Cheung, Diego Cobos-Roa, Julien Cohen-Waeber, Brian D. Collins, Luke Ehrensing, Dan A. Farber, W. Michael Hanneman, Leslie F. Harder, Kofi S. Inkabi, Anne M. Kammerer, Deniz Karadeniz, Robert E. Kayen, Robb E.S. Moss, Jennifer Nicks, Seshu Nimala, Juan M. Pestana, Jim Porter, Keunyong Rhee, Michael F. Riemer, Karlene Roberts, J. David Rogers, Rune Storesund, Anand V. Govindasamy, Xavier Vera-Grunauer, Joseph E. Wartman, Conor M. Watkins, Ed Wenk, Jr., Solomon C. Yim

Civil and Environmental Engineering

This report presents the results of an investigation of the performance of the New Orleans regional flood protection system during and after Hurricane Katrina, which struck the New Orleans region on August 29, 2005. This event resulted in the single most costly catastrophic failure of an engineered system in history. Current damage estimates at the time of this writing are on the order of $100 to $200 billion in the greater New Orleans area, and the official death count in New Orleans and southern Louisiana at the time of this writing stands at 1,293, with an additional 306 deaths in …

Investigation Of The Performance Of The New Orleans Flood Protection System In Hurricane Katrina On August 29, 2005: Volume 2, Raymond B. Seed, Robert G. Bea, Remon I. Abdelmalak, Adda G. Athanasopoulos, Gordon P. Boutwell, Jr., Jonathan D. Bray, Jean-Louis Briaud, Carmen Cheung, Diego Cobos-Roa, Julien Cohen-Waeber, Brian D. Collins, Luke Ehrensing, Dan A. Farber, W. Michael Hanneman, Leslie F. Harder, Kofi S. Inkabi, Anne M. Kammerer, Deniz Karadeniz, Robert E. Kayen, Robb E.S. Moss, Jennifer Nicks, Seshu Nimala, Juan M. Pestana, Jim Porter, Keunyong Rhee, Michael F. Riemer, Karlene Roberts, J. David Rogers, Rune Storesund, Anand V. Govindasamy, Xavier Vera-Grunauer, Joseph E. Wartman, Conor M. Watkins, Ed Wenk, Jr., Solomon C. Yim

Civil and Environmental Engineering

No abstract provided.

Self-Assembled Composite Nano-/Micronecklaces With Sio2 Beads In Boron Strings, Hai Ni, Xiaodong Li

Faculty Publications

Nano-/micronecklaces with SiO₂ beads in boron strings were synthesized by simply sublimating the desired powders in a sealed quartz tube at high temperature. The boron strings have a rectangular cross section with width varying from 80to1000nm while the SiO₂ beads bear either spindle or spherical shape with a size ranging from 100nmto5μm. The spacing between the SiO₂ beads is uniform in each boron string. Both the boron strings and the SiO₂ beads are amorphous and free of defects. The supersaturated vapors of silicon and oxygen induced the SiO₂ bead formation.

Modeling And Validation Of Tension-Element Based Mechanisms For Golf Ball-Club Impact, Aaron Robison

Theses and Dissertations

Previous work has systematically and numerically demonstrated feasibility and performance benefits of the tension-element concept in golf club heads; however, higher fidelity models needed to be created and validated for this concept. There is a need for more accurate models for this concept to further investigate its performance benefits. Performance is measured in terms of impact efficiency of the ball and head and is referred to as coefficient of restitution (COR). COR is affected by the dynamic effective face stiffness and mass properties of the club. This thesis creates and validates high-fidelity, non-linear, dynamic finite element models for the tension-element …