Engineering Commons^™

Effect Of Nozzle Base Material On The Rate Of Clogging During The Continuous Casting Of Aluminum-Killed Steels, Luis Trueba, Kent D. Peaslee, Jeffrey D. Smith, Musa Karakus

Materials Science and Engineering Faculty Research & Creative Works

One approach to solving the problem of nozzle clogging during the continuous casting of aluminum-killed steels is through careful selection of nozzle materials. in this study, the rate of clogging was measured while casting steel through simulated nozzles produced from alumina, zirconia, magnesia, zirconia-graphite, and alumina-graphite - three common base materials and two common carbon-containing nozzle materials. Spent nozzles were characterized using optical and cathodoluminescence microscopy. Interactions between the nozzles and steel were not observed in the alumina, zirconia, and zirconia-graphite nozzles. Slight interactions were observed in the magnesia nozzles as alumina inclusions within the steel interacted with the nozzle …

Effect Of Welding Parameters On Properties Of 5052 Al Friction Stir Spot Welds, T. A. Freeney, S. R. Sharma, Rajiv S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Effect of process parameters on friction stir spot welding (FSSW) of 5052 Al alloy has been evaluated. a plunge type FSSW machine was used for this study. Sheet thicknesses of 1 and 1.6mm were used. the tool rotation rate was varied between 1000 and 3000 rpm. the tool plunge rate and dwell time was varied to give weld cycle of 1-4 seconds. Shear tests were performed in 2 sheet and 3 sheet configurations to determine the influence of processing parameters on the mechanical properties of lap joint FSSWs. Higher joint strengths were observed at lower tool rotation rates. Copyright © …

Intelligent Tool For Determining The True Harmonic Current Contribution Of A Customer In A Power Distribution Network, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Marty L. Page, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Customer loads connected to electricity supply systems may be broadly categorized as either linear or nonlinear. Nonlinear loads inject harmonics into the power network. Harmonics in a power system are classified as either load harmonics or as supply harmonics depending on their origin. The source impedance also impacts the harmonic current flowing in the network. Hence any change in the source impedance is reflected in the harmonic spectrum of the current. This paper proposes a novel method based on Artificial Neural Networks to isolate and evaluate the impact of the source impedance change without disrupting the operation of any load, …

Online Training Of A Generalized Neuron With Particle Swarm Optimization, R. Kiran, Ganesh K. Venayagamoorthy, Sandhya R. Jetti

Electrical and Computer Engineering Faculty Research & Creative Works

Neural networks are used in a wide number of fields including signal and image processing, modeling and control and pattern recognition. Some of the most common type of neural networks is the multilayer perceptrons and the recurrent neural networks. Most of these networks consist of large number of neurons and hidden layers, which results in a longer training time. A Generalized Neuron (GN) has a compact structure and overcomes the problem of long training time. Due to its simple structure and lesser memory requirements, the GN is attractive for hardware implementations. This paper presents the online training of a GN …

Heuristics And Genetic Algorithms, Michael D. Mobley, Cihan H. Dagli, David Enke

Engineering Management and Systems Engineering Faculty Research & Creative Works

Genetic algorithms are design tools used in generating optimal solutions. While they can often be shown to outperform various heuristic methods and hybrid approaches, using a combination of evolutionary algorithms and heuristic approaches can generate an optimal solution more quickly than either of the two methods independently. Our purpose is to provide an overview of genetic algorithms, to discuss the types of problems that lend themselves to being solved by genetic algorithms, and to identify heuristics that have been shown to aid genetic algorithms in their quest for optimal solutions. While the sample problems discussed in this paper are generally …

Applying The Mahalanobis-Taguchi System To Vehicle Handling, Kioumars Paryani, Elizabeth A. Cudney, K. M. Ragsdell

Engineering Management and Systems Engineering Faculty Research & Creative Works

The Mahalanobis-Taguchi system (MTS) is a diagnosis and forecasting method using multivariate data. Mahalanobis distance (MD) is a measure based on correlations between the variables and patterns that can be identified and analyzed with respect to a base or reference group. The MTS is of interest because of its reported accuracy in forecasting using small, correlated data sets. This is the type of data that is encountered with consumer vehicle ratings. MTS enables a reduction in dimensionality and the ability to develop a scale based on MD values. MTS identifies a set of useful variables from the complete data set …

Comparison Of Combustion Sources And Measurement Techniques For Particulates Emitted From Engines And A Power Plant, Matthew F. Chandler

Masters Theses

"Sub-micron particulates emitted from various combustion sources have serious negative impacts on human health and the environment. It is essential to accurately characterize the physical properties of these particulates including size, shape, structure, and chemical composition in order to monitor, regulate, and model the various transport, toxic, optical, chemical, and deposition properties which dictate their harmful effects. This study consists of two related investigations involving the application of diagnostics methods to characterization and comparison of combustion generated particulate emissions from various sources. The first investigation includes the measurement of particulates emitted from a compression-ignition (diesel) engine using two independent measurement …

The Flood Frog: An Autonomous Wireless Device For Flood Detection And Monitoring, Valerio Plessi

Masters Theses

"Accurate real time monitoring is gaining critical importance in a broad range of domains. Of particular interest to this research is the development of monitoring and detection systems for environmental and structural phenomena. Transportation infrastructures, in particular bridges, provide examples for both categories. Flooding of low water bridges is one example of rapidly evolving environmental phenomena, while stress and vibration are structural phenomena in need of monitoring.

Early warning and advanced preparation for emergency are two of the most effective lines of defense against catastrophic events, where real time monitoring can facilitate containment and recovery efforts. The operating environment of …

Maxwell-Wagner Relaxations And Their Contributions To The High Permittivity Of Calcium Copper Titanate Ceramics, Wei Li, Robert W. Schwartz

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Calcium copper titanate ceramics were fabricated by cold isostatic pressing at various calcination and sintering conditions. Depending on fabrication condition, three electrical responses were observed in the combined modulus and impedance plots, indicating the presence of two Maxwell-Wagner relaxations. These electrical responses show different response to temperature and applied field. The activation energies, as well as the driving force factors, were calculated for these relations. The determined activation energy values are in the range of 0.57 to 0.65 eV. The contribution of Maxwell-Wagner relaxations to the high permittivity of CCTO and related materials is briefly discussed.

Fast Time-Varying Dispersive Channel Estimation And Equalization For 8-Psk Cellular System, Sang-Yick Leong, Jingxian Wu, Chengshan Xiao, Jan C. Olivier

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel channel-estimation scheme for an 8-PSK enhanced data rates for GSM evolution (EDGE) system with fast time-varying and frequency-selective fading channels is presented. via a mathematical derivation and simulation results, the channel impulse response (CIR) of the fast fading channel is modeled as a linear function of time during a radio burst in the EDGE system. Therefore, a least-squares-based method is proposed along with the modified burst structure for time-varying channel estimation. Given that the pilot-symbol blocks are located at the front and the end of the data block, the LS-based method is able to estimate …

Creating Cascading Failure Scenarios In Interconnected Power Systems, Badrul H. Chowdhury, Sushant Barave

Electrical and Computer Engineering Faculty Research & Creative Works

The reported catastrophic failures of power systems from different geographical parts of the world often point to cascading outage events of system elements that eventually had led to system blackout. Although the initiating events of these cascading failures may, at times, be avoidable by vegetation management or proper protection settings, the occurrence of such an event as well as the eventual impact cannot always be predicted. There is much debate in the industry whether the operator has enough time to apply countermeasures to avoid blackouts. Besides, the process of determining effective countermeasures cannot be deemed accurate unless a system has …

Design Of Optimal Pi Controllers For Doubly Fed Induction Generators Driven By Wind Turbines Using Particle Swarm Optimization, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

When subjected to transient disturbances in the power grid, the variable frequency converter (VFC) is the most sensitive part in the variable-speed wind turbine generator system (WTGS) equipped with a doubly fed induction generator (DFIG). The VFC is normally controlled by a set of PI controllers. Tuning these PI controllers is a tedious work and it is difficult to tune the PI gains optimally due to the nonlinearity and the high complexity of the system. This paper presents an approach to use the particle swarm optimization algorithm to design the optimal PI controllers for the rotor-side converter of the DFIG. …

Observability Conditions For Target States With Bearing-Only Measurements In Three-Dimensional Case, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

In target tracking with a passive sensor such as infrared seekers, angle-only information is determined. In this case no information about the range of the target is provided and unobservable system is resulted. This paper studies the observability of discrete time three-dimensional bearing-only target tracking. The target is assumed to be moving in a straight line while a single moving observer (own-ship) measures its relative (elevation and azimuth) bearing angles. By transforming the inherently nonlinear bearing measurements into a pseudo-linear form, a linear Least Squares (LS) estimator is formulated. Observability is then analyzed by studying the solvability of the associated …

Disinfection Of Swine Wastewater Using Chlorine, Ultraviolet Light And Ozone, John J. Macauley, Zhimin Qiang, Rao Y. Surampalli, Melanie R. Mormile, Craig D. Adams

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Veterinary antibiotics are widely used at concentrated animal feeding operations (CAFOs) to prevent disease and promote growth of livestock. However, the majority of antibiotics are excreted from animals in urine, feces, and manure. Consequently, the lagoons used to store these wastes can act as reservoirs of antibiotics and antibiotic-resistant bacteria. There is currently no regulation or control of these systems to prevent the spread of these bacteria and their genes for antibiotic resistance into other environments. This study was conducted to determine the disinfection potential of chlorine, ultraviolet light and ozone against swine lagoon bacteria. Results indicate that a chlorine …

A Non-Isotropic Model For Mobile-To-Mobile Fading Channel Simulations, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

Accurate modeling of the mobile-to-mobile fading channel is critical not only to physical layer transceiver design but also to the design and performance of link and network layers. A two-dimensional nonisotropic scattering model is developed in this paper, which adopts the von Mises probability density function for the angle of departure surrounding the transmitter and the angle of arrival surrounding the receiver. This model includes the isotropic scattering channel and the base-to-mobile channel as special cases. An efficient computer simulation model is also developed to generate the non-isotropic scattering channel impulse responses. Statistical properties of the non-isotropic mobile-to-mobile channels are …

Echo State Networks For Determining Harmonic Contributions From Nonlinear Loads, Joy Mazumdar, Ganesh K. Venayagamoorthy, Frank C. Lambert, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the application of a new kind of recurrent neural network called Echo State Networks (ESNs) for the problem of measuring the actual amount of harmonic current injected into a power network by a nonlinear load. The interaction between loads connected to a point of common coupling (PCC) is a highly dynamic process. The determination of true harmonic current injection by individual loads is further complicated by the fact that the supply voltage waveform at the PCC is distorted by other loads at the PCC or further upstream and is therefore rarely a pure sinusoid. Harmonics in a …

Numerical Simulations Of The Interaction Of Internal Waves With A Shelf Break, S. K. Venayagamoorthy, O. B. Fringer

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The energetics of the interaction of internal gravity waves with a shelf break is investigated by means of high-resolution two-dimensional numerical simulations, with an emphasis on understanding the partitioning of the internal wave energy over the course of the interaction process and the subsequent dynamics of the onshore propagating internal waves. Some of the energy is dissipated as a result of the instabilities associated with breaking, while the remaining energy is either reflected back away from or transmitted onto the shelf. We employ an analysis of the distribution of the energy flux across the shelf break taking into account the …

Effect Of Seeding Materials And Mixing Strength On Struvite Precipitation, Jun Wang, Joel Gerard Burken, Xiaoqi Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Struvite Precipitation Has Increasing Interest as a Technology for Removing and Recovering Phosphorus from Wastewater Streams. Many Chemical Factors Have Been Studied, Such as Optimum PH Values and Component-Ion Molar Ratios, Yet, Understanding of Physical Aspects is Lacking. Two Physical Parameters Were Tested: (1) Seeding Material Addition and (2) Mixing. Objectives Were to Evaluate Three Seeding Materials and to Optimize Mixing Conditions for Struvite-Crystal Precipitation, Growth, and Subsequent Sedimentation. Results Confirm that Mixing Strength and Proper Seeding Materials Increase Crystal Size and Improve Settleability. for Unseeded Solutions, Optimum Phosphorus Removal Was Achieved at a Mixing Strength of G = 76 …

Molecular Mass And Dynamics Of Poly(Methyl Acrylate) In The Glass Transition Region, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The segmental dynamics of bulk poly(methyl acrylate) (PMA) were studied as a function of molecular mass in the glass-transition region using 2H NMR and modulated differential scanning calorimetry (MDSC). Quadrupole-echo 2H NMR spectra were obtained for four samples of methyl-deuterated PMA-d3 with different molecular masses. The resulting spectra were fit using superpositions of simulated spectra generated from the MXQET simulation program, based on a model incorporating nearest-neighbor jumps from positions on the vertices of a truncated icosahedron (soccer-ball shape). The lower molecular-mass samples, influenced by the presence of more chain ends, showed more heterogeneity (broader distribution) and lower glass transitions …

Segmental Dynamics In Poly(Methyl Acrylate) On Silica: Molecular-Mass Effects, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The effect of molecular mass on the segmental dynamics of poly(methyl acrylate) (PMA) adsorbed on silica was studied using deuterium quadrupole-echo nuclear magnetic resonance (NMR) and modulated differential scanning calorimetry. Samples adsorbed on silica (all about 1.5 mg PMA/m2 silica) were shown to have more restricted segmental mobility, and higher Tg's, than the corresponding bulk PMA samples. Around the glass-transition region, adsorbed samples exhibited segmental mobility, which could be classified as heterogeneous due to a superposition of more-mobile and less-mobile components present in the deuterium NMR spectra. This heterogeneity was consistent with a motional gradient with more-mobile segments near the …

Forecasting Using The Mahalanobis-Taguchi System In The Presence Of Collinearity, Elizabeth A. Cudney, Kenneth M. Ragsdell

Engineering Management and Systems Engineering Faculty Research & Creative Works

The Mahalanobis Taguchi System is a diagnosis and forecasting method for multivariate data. Mahalanobis distance is a measure based on correlations between the variables and different patterns that can be identified and analyzed with respect to a base or reference group. the issue of multicollinearity is not adequately addressed in the MTS method. in cases where strong relationships exist between variables, the correlation matrix becomes almost singular, and the inverse matrix is not accurate. Multicollinearity can be handled by utilizing the adjoint matrix of the correlation matrix and Gram-Schmidt orthogonalization. This paper presents a case study of the MTS methodology …

Modeling Net-Centric System Of Systems Using The Dystems Modeling Language Sysml, Rao Madwaraj, Sreeram Ramakrishnan, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Understanding the operations of a large 'net-centric system-of-systems requires in-depth knowledge of the interfaces among the various systems, sub-systems and components. Architectural modeling can help in reducing the complexity involved in designing such large networked systems. An example of such a complex system is the Global Earth Observation System of Systems (GEOSS) - a system for monitoring and collecting information related to Earth's resources. This paper demonstrates the use of Systems Modeling Language (SysML), which supports specification, analysis, design, verification and validation of a broad range of complex systems, to model some aspects of the GEOSS. The paper discusses issues …

An Investigation Of The Effect Of Chassis Connections On Radiated Emi From Pcbs, N. Kobayashi, T. Harada, A. Shaik, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

This paper investigates the effect of grounding posts when printed circuit boards are mounted near and parallel to a metal plate or chassis. Specifically, experimental data showing changes in radiated emission levels are explained by means of coupling phenomena between a power bus, a chassis cavity including grounding posts, and a cable connected to the power bus. This coupling is modeled using SPICE and the results are combined with an equivalent magnetic current source model to estimate the radiated emissions from various printed circuit board configurations. the calculated results are shown to be consistent with the corresponding experimental data. © …

Emc Expert Systems For Evaluating Automotive Designs, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

The automobiles of the future are being designed on computers and a significant amount of performance and safety testing is done using computer models. by the time the first hardware prototype is built, many critical design decisions affecting intersystem and intra-system electromagnetic compatibility (EMC) have been made. Therefore, it is becoming increasingly important to perform the first EMC design review well before any hardware is available to test. Automotive EMC expert systems examine the relevant aspects of an automotive design while it is still on the computer to spot design features that are likely to cause EMC problems. © 2006 …

Message From The Pdm Workshop Chair, Ishfaq Ahmad, Shoukat Ali, Suchi Bhandharkar, Hesham El-Rewini, Kamal Karlapalem, Ashraf Kassim, Ashfaq Khokhar, Yu Kwong Kwok, Jack Lee, Qing Li, John Lui, Yu Su, R. Vaidyanathan, Bharadwaj Veeravalli

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Modeling Radiated Emissions From Cables Attached To Printed Circuit Boards Driven By Power Bus Noise, K. Morishita, N. Kobayashi, T. Harada, H. Ke, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes a two-step technique for modeling the radiated electromagnetic emissions from a printed circuit board with attached cables when the source of the emissions is noise between the board's power and ground planes. the first step calculates the electric fields at the edges of the power-ground plane pair. the second step replaces the power plane with equivalent sources embedded within the ground plane structure. Examples are provided that demonstrate the accuracy of this approach. © 2006 IEEE.

Power System Control With An Embedded Neural Network In Hybrid System Modeling, Seung-Mook Baek, Jung-Wook Park, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The output limits of the power system stabilizer (PSS) can improve the system damping performance immediately following a large disturbance. Due to non-smooth nonlinearities from the saturation limits, these values cannot be determined by the conventional tuning methods based on linear analysis. Only ad hoc tuning procedures can been used. A feedforward neural network (FFNN) (with a structure of multilayer perceptron neural network) is applied to identify the dynamics of an objective function formed by the states, and thereafter to compute the gradients required in the nonlinear parameter optimization. Moreover, its derivative information is used to replace that obtained from …

Predicting Load Harmonics In Three Phase Systems Using Neural Networks, Joy Mazumdar, Frank C. Lambert, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a artificial neural network (ANN) based method for the problem of measuring the actual harmonic current injected into a power system network by three phase nonlinear loads without disconnecting any loads from the network. The ANN directly estimates or identifies the nonlinear admittance (or impedance) of the load by using the measured values of voltage and current waveforms. The output of this ANN is a waveform of the current that the load would have injected into the network if the load had been supplied from a sinusoidal voltage source and is therefore a direct measure of load …

A Fault-Tolerant P-Q Decoupled Control Scheme For Static Synchronous Series Compensator, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Control of nonlinear devices in power systems relies on the availability and the quality of sensor measurements. Measurements can be corrupted or interrupted due to sensor failure, broken or bad connections, bad communication, or malfunction of some hardware or software (referred to as missing sensor measurements in this paper). This paper proposes a fault-tolerant control scheme (FTCS) for a static synchronous series compensator (SSSC). This FTCS consists of a sensor evaluation and (missing sensor) restoration scheme (SERS) cascaded with a P-Q decoupled control scheme (PQDC). It is able to provide effective control to the SSSC when single or multiple crucial …

Calculating Static Field And Charge Distributions Using Full-Wave Boundary Element Methods, Todd H. Hubing, Haixin Ke

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.