Engineering Commons^™

Exploration Of Artificial Multiferroic Thin-Film Heterostructures Using Composition Spreads, K.-S. Chang, M. A. Aronova, C.-L. Lin, M. Murakami, M.-H. Yu, Jason R. Hattrick-Simpers, O. O. Famodu, S. Y. Lee, R. Ramesh, M. Wuttig, I. Takeuchi, C. Gao, L. A. Bendersky

Faculty Publications

We have fabricated a series of composition spreads consisting of ferroelectric BaTiO₃ and piezomagnetic CoFe₂O₄ layers of varying thicknesses modulated at nanometer level in order to explore artificial magnetoelectricthin-film heterostructures. Scanning microwavemicroscopy and scanning superconducting quantum interference device microscopy were used to map the dielectric and magnetic properties as a function of continuously changing average composition across the spreads, respectively. Compositions in the middle of the spreads were found to exhibit ferromagnetism while displaying a dielectric constant as high as ≈120.

Series Solution To The Transient Convective Diffusion Equation For A Rotating Disk Electrode, Shiriram Santhanagopalan, Ralph E. White

Faculty Publications

A series solution to the transient convective diffusion equation for the rotating disc electrode system is presented and compared to previously reported solutions. The solution presented here is for the entire time domain and agrees well with both the short and long time solutions presented earlier in the literature.

Parameter Estimates For A Pemfc Cathode, Qingzhi Guo, Vijay A. Sethuraman, Ralph E. White

Faculty Publications

Five parameters of a model of a polymer electrolyte membrane fuel cell (PEMFC) cathode (the volume fraction of gas pores in the gas diffusion layer, the volume fraction of gas pores in the catalyst layer, the exchange current density of the oxygen reduction reaction, the effective ionic conductivity of the electrolyte, and the ratio of the effective diffusion coefficient of oxygen in a flooded spherical agglomerate particle to the square of that particle radius) were determined by least-squares fitting of experimental polarization curves. The values of parameters obtained in this work indicate that ionic conduction and gas-phase transport are two …

Analytical Solution For The Impedance Of A Porous Electrode, Sheba Devan, Venkat R. Subramanian, Ralph E. White

Faculty Publications

A macrohomogeneous model is presented for a porous electrode that includes coupled potential and concentration gradients with linear kinetics. The equations are solved to obtain an analytical expression for the impedance of a porous electrode. Complex plane plots are presented that illustrate two well-defined arcs: a kinetic arc and a diffusion arc with their time constants far apart. The effects of parameters such as exchange current density, porosity, diffusion coefficient, thickness, and interfacial area on the impedance spectra are presented. The usefulness of the analytical solution in investigating the effect of solution phase diffusion is also presented.

A Steady-State Impedance Model For A Pemfc Cathode, Qingzhi Guo, Ralph E. White

Faculty Publications

A model for the simulation of the steady-state impedance response of a polymer electrolyte membrane fuel cell (PEMFC) cathode is presented. The catalyst layer of the electrode is assumed to consist of many flooded spherical agglomerate particles surrounded by a small volume fraction of gas pores. Stefan-Maxwell equations are used to describe the multicomponent gas-phase transport occurring in both the gas diffusion layer and the catalyst layer of the electrode. Liquid-phase diffusion of O2 is assumed to take place in the flooded agglomerate particles. Newman’s porous electrode theory is applied to determine over-potential distributions. © 2004 The Electrochemical Society. All …

Cycle Life Modeling Of Lithium-Ion Batteries, Gang Ning, Branko N. Popov

Faculty Publications

A first-principles-based charge-discharge model was developed to simulate the capacity fade of Li-ion batteries. The model is based on the loss of active lithium ions due to solvent reduction reaction and on the rise of the anode film resistance. The effect of parameters such as exchange current density, depth of discharge (DOD), end of charge voltage, film resistance, and the overvoltage of parasitic reaction were studied quantitatively. The model controls the required DOD by controlling the discharge time and estimates the end of discharge voltages as a function of cycle number.

Development Of First Principles Capacity Fade Model For Li-Ion Cells, P. Ramadass, Bala Haran, Parthasarathy M. Gomadam, Ralph E. White, Branko N. Popov

Faculty Publications

A first principles-based model has been developed to simulate the capacity fade of Li-ion batteries. Incorporation of a continuous occurrence of the solvent reduction reaction during constant current and constant voltage (CC-CV) charging explains the capacity fade of the battery. The effect of parameters such as end of charge voltage and depth of discharge, the film resistance, the exchange current density, and the over voltage of the parasitic reaction on the capacity fade and battery performance were studied qualitatively. The parameters that were updated for every cycle as a result of the side reaction were state-of-charge of the electrode materials …

Development Of Novel Method For Preparation Of Pemfc Electrodes, Hansung Kim, Branko N. Popov

Faculty Publications

A method based on pulse electrodeposition technique was developed for preparation of membrane electrode assemblies (MEAs). In this approach, platinum is deposited directly on the surface of the carbon electrode. The method ensures most of the platinum to be in close contact with the membrane. Using this method it is possible to increase the Pt/C ratio up to 75 wt % near the surface of the electrode resulting in a 5 µm thick catalyst layer. The MEA prepared by pulse electrodeposition exhibits a current density of 0.33 A/cm² at 0.8 V with platinum loading of 0.25 mg of Pt/cm …

Solvent Diffusion Model For Aging Of Lithium-Ion Battery Cells, Harry J. Ploehn, Premanand Ramadass, Ralph E. White

Faculty Publications

This work presents a rigorous continuum mechanics model of solvent diffusion describing the growth of solid-electrolyte interfaces (SEIs) in Li-ion cells incorporating carbon anodes. The model assumes that a reactive solvent component diffuses through the SEI and undergoes two-electron reduction at the carbon-SEI interface. Solvent reduction produces an insoluble product, resulting in increasing SEI thickness. The model predicts that the SEI thickness increases linearly with the square root of time. Experimental data from the literature for capacity loss in two types of prototype Li-ion cells validates the solvent diffusion model. We use the model to estimate SEI thickness and extract …

Interaction Effects Of Slurry Chemistry On Chemical Mechanical Planarization Of Electroplated Copper, Peter A. Miranda, Jerome A. Imonigie, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

Recent studies have been conducted investigating the effects of slurry chemistry on the copper CMP process. Slurry pH and hydrogen peroxide concentration are two important variables that must be carefully formulated in order to achieve desired removal rates and uniformity. In applications such as throughwafer vertical interconnects, slurry chemistry effects must be thoroughly understood when copper plating thicknesses can measure up to 20 microns thick. The species of copper present on the surface of the wafer can be controlled through formulation of the slurry chemistry resulting in minimizing non-uniformity while aggressively removing copper. Using a design of experiments (DOE) approach, …

Investigation Of A Fuzzy-Neural Network Application In Classification Of Soils Using Ground-Penetrating Radar Imagery, Lameck O. Odhiambo, R. S. Freeland, R. E. Yoder, J. W. Hines

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Errors associated with visual inspection and interpretations of radargrams often inhibit the intensive surveying

of widespread areas using ground-penetrating radar (GPR). To automate the interpretive process, this article presents an

application of a fuzzy-neural network (F-NN) classifier for unsupervised clustering and classification of soil profiles using

GPR imagery. The classifier clusters and classifies soil profile strips along a traverse based on common pattern similarities

that can relate to physical features of the soil (e.g., number of horizons; depth, texture, and structure of the horizons; and

relative arrangement of the horizons, etc.). This article illustrates this classification procedure by its application …

Review Of Spokane River Model For Washington Department Of Ecology, Chris Berger, Robert Leslie Annear, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

This memorandum discusses changes made to the Spokane River model calibration since the original calibration of the model discussed in the following reports: Annear et al. (2001), Berger at al. (2002), Slominski et al. (2002), and Berger et al. (2003). The first group of refinements was made by the Washington Department of Ecology. Additional changes were made by Portland State University (PSU) and were discussed in this report along with the results of two alternative calibrations. The last section displays the original calibration results from Berger et al. (2003) as a basis for comparison to the changes made by Ecology …

Willamette River Basin Temperature Tmdl Model: Boundary Conditions And Model Setup, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and …

Material Length Scales In Gradient-Dependent Plasticity/Damage And Size Effects: Theory And Computation, Rashid Kamel Abu Al-Rub

LSU Doctoral Dissertations

Structural materials display a strong size-dependence when deformed non-uniformly into the inelastic range: smaller is stronger. This effect has important implications for an increasing number of applications in structural failure, electronics, functional coatings, composites, micro-electro-mechanical systems (MEMS), nanostructured materials, micro/nanometer fabrication technologies, etc. The mechanical behavior of these applications cannot be characterized by classical (local) continuum theories because they incorporate no ‘material length scales’ and consequently predict no size effects. On the other hand, it is still not possible to perform quantum and atomistic simulations on realistic time and structures. It is therefore necessary to develop a scale-dependent continuum theory …

Optimization Of A Skewed Logistic Distribution With Respect To The Kolmogorov-Smirnov Test, James Charles Finney

LSU Doctoral Dissertations

The four-parameter kappa distribution (Hosking 1994) was analyzed with respect to the various possible shapes of the probability density function. The general form for the cumulative distribution function when both h and k are non-zero is: F(x) = { 1 - h [ 1 - k ( x - ξ ) / α ]^1/k }^1/h. The parameters h and k work together to define the function's shape, ξ affects location, and α is the scale parameter. A method of selecting parameters to minimize the Kolmogorov-Smirnov test statistic, D, was developed. The technique was first described for the …

Wideband Channel Model For Aeronautical Telemetry, Christian Bettweiser, Adam Davis, Michael D. Rice

Faculty Publications

A multipath channel model for wideband aeronautical telemetry links is presented. Channel sounding data were collected at Edwards AFB, CA, at both L-band and lower S-band. Frequency domain analysis techniques were used to evaluate candidate channel models. The channel model is composed of three propagation paths: a line-of-sight direct path and two specular reflections. The first specular reflection is characterized by a relative amplitude of 70% to 96% of the line-of-sight amplitude and a delay of 10—80 ns. This path is the result of “ground bounces” off the dry lake bed at Edwards and is a typical terrain feature at …

Building A Comprehensive Energy Model For Off-Highway Vehicles With Emphasis On Vehicle Thermal Control Systems, Ayhan Zora

Dissertations and Theses @ UNI

Utilizing machine and thermal system simulations (vehicle energy models) can be very helpful for vehicle manufacturing companies to develop a machine with acceptable component temperatures, less heat loads to the vehicle cooling systems, and reduced emissions that will also reduce overall product development cycle.

Energy models of vehicles were developed mostly in the automotive industry, and most of these studies were based on partial energy models.

The aim of this research study was to create a comprehensive energy model for agricultural machinery, which will be a basis for future work on similar products. A tractor model from a Midwest off-road …

Uav Coordinate Frames And Rigid Body Dynamics, Randal Beard

Faculty Publications

This section describes the various coordinate systems that are used to describe the position of orientation of aircraft, and the transformation between these coordinate systems. It is necessary to use several different coordinate systems for the following reasons: Newton's equations of motion are given the coordinate frame attached to the UAV. Some of the on-board sensors take measurements in the body frame, e.g., rate gyros, while some of the sensors take measurements in the inertial frame, e.g., GPS. Aerodynamics forces and torques are exerted in the body frame. Most system requirements, e.g., flight trajectories, are specified in the inertial frame.

Modeling The Direct Solar Conversion Of Co2 To Co And O2, Thomas H. Fletcher

Faculty Publications

At high temperatures (greater than 2300 K), CO₂ is known to dissociate to CO and O. A prototype solar collector was previously demonstrated to achieve such high temperatures, achieving 4-6 mol % CO in the product stream from an inlet stream of pure CO₂. This paper describes the results of computer modeling performed to determine the flow, temperature, and reactions occurring in the prototype device. Of particular interest are the heat-transfer and reaction mechanisms involved and how much photolysis occurs in the prototype. Predictions were performed with two different computational fluid dynamic codes (Fluent and PCGC-3). The …

Design And Analysis Of An Air Filter Sensor For A Residential Heating And Cooling System, Cheng Y. Lin, Steve C. Hsiung, Alok K. Verma, Gary R. Crossman

Engineering Technology Faculty Publications

This is a design project of an air-filter sensor to be used in home heating and cooling system. The project includes conceptual design, analysis, implementation, tests and modifications. First, the air quality and power consumption between a clean air filter and a dirty air filter is studied. Then, a photo sensor circuit with an ultra high brightness LED emitter and a phototransistor receiver is used to detect dust particles. A red warning LED lights up when a specified amount of dust is collected on the filter and blocks the light beam between the emitter and the receiver. The emitter and …

Design, Development, And Delivery Of Certificate Programs For Funding Opportunities And Industry Collaboration, Carol Considine, Paul Kauffmann

Engineering Technology Faculty Publications

Many engineering technology departments have four general areas that are used for evaluation of tenure and promotion. These areas include teaching, research and scholarly activities, service, and other professional activities. Although teaching is the primary mission in most engineering technology programs, external funding as part of the research area is playing a larger role in tenure decisions at many universities. Many faculty members in engineering technology programs come from an industrial background and do not have a specific research area of interest and contacts within the research community. These faculty members must look at other avenues to develop the external …

An Integration Of Pc Hardware & Software In Teaching Engineering Technology Courses, Steve Hsiung, Richard Jones

Engineering Technology Faculty Publications

As technology advances, the price of a PC drops dramatically. This trend has resulted in PCs that are complex, powerful, and very affordable. Today's PC is a popular and essential tool in teaching software programming course(s) in C, C++, Visual Basic, or Java, running commercial software supporting courses in circuit simulation/design or circuit board layout, and acting as a workstation to gain access to the Internet or LAN networks. In most Engineering Technology curricula there is a limited amount of linkage between those PC applications. The actual effort to merge the hard-gained knowledge of hardware & software concepts together through …

Automation Laboratory Development With Design Implementation Scheme And Simulation Software, Cheng Y. Lin, Gary R. Crossman

Engineering Technology Faculty Publications

This paper describes the development of the Automation Control Lab in the Mechanical Engineering Technology Program of the Engineering Technology Department at Old Dominion University. The reorganization goal of the development is to help students design, test, and implement their automation designs effectively. Three processes are adopted to achieve this goal: (1) floor-plan design and inventory control of the components, (2) using Automation Studio to dynamically check each design, and (3) using industrial Programmable Logic Controllers (PLC) controllers to download PLC programs.

Assessment Methods For Comparison Of On-Camps And Distance Learning Laboratory Courses In An Engineering Technology Program, John R. Hackworth, Richard L. Jones

Engineering Technology Faculty Publications

Assessment methodology and results for two Electrical Engineering Technology laboratory courses are shown. In these cases, courses are offered in both the traditional on- campus and non-traditional distance learning format, assessment methods are prescribed, assessment data are taken, and the results compiled and compared. Student comments are included which also support the assessment data. In addition, this paper describes ways in which the laboratory courses are structured in order to make the assessment process easier to manage. Pedagogical issues are addressed that were encountered when constructing the distance learning laboratory courses to assure that the learning experience could equal or …

Enhancing Instruction In Lean Manufacturing Through Development Of Simulation Activities In Shipbuilding Operations, Alok K. Verma, James Hughes, Scott Christman

Engineering Technology Faculty Publications

Lean Manufacturing is a powerful philosophy that advocates minimization of waste within an organization. The adoption of Lean Manufacturing philosophy by major manufacturers has created a demand for qualified personnel in this area. A training program in Lean Enterprise was developed by Old Dominion University for the Apprentice School at Northrop Grumman Newport News. Physical simulation activities are an integral part of this training program. Simulation activities related to shipbuilding operations have been incorporated in the Lean training course. These activities have been used in the Business Operations course for three semesters. Results show increased student participation and better understanding …

Surveying Cost Growth, Michael A. Greiner, Vince Sipple, Edward D. White

Faculty Publications

Cost growth that weapon systems incur throughout their acquisition life cycle concerns those who work in the acquisition environment. One way to reduce the amount of unexpected cost growth is to develop better cost estimates. In attaining better cost estimates though, it is often helpful to understand and account for potential cost drivers. Several cost studies, some of which specifically focus on the aircraft industry, have been performed documenting and investigating these growth factors. Overviews of these various cost growth studies are presented as other tools for the cost estimators and program managers.

Pperfgrid: A Grid Services-Based Tool For The Exchange Of Heterogeneous Parallel Performance Data, John Jared Hoffman

Dissertations and Theses

This thesis details the approach taken in developing PPerfGrid. Section 2 discusses other research related to this project. Section 3 provides general background on the technologies utilized in PPerfGrid, focusing on the components that make up the Grid services architecture. Section 4 provides a description of the architecture of PPerfGrid. Section 5 details the implementation of PPerfGrid. Section 6 presents tests designed to measure the overhead and scalability of the PPerfGrid application. Section 7 suggests future work, and Section 8 concludes the thesis.

Energy Aware Design And Analysis For Synchronous And Asynchronous Circuits, Jia Di

Retrospective Theses and Dissertations

Power dissipation has become a major concern for IC designers. Various low power design techniques have been developed for synchronous circuits. Asynchronous circuits, however. have gained more interests recently due to their benefits in lower noise, easy timing control, etc. But few publications on energy reduction techniques for asynchronous logic are available.

Power awareness indicates the ability of the system power to scale with changing conditions and quality requirements. Scalability is an important figure-of-merit since it allows the end user to implement operational policy. just like the user of mobile multimedia equipment needs to select between better quality and longer …

Adaptive Intelligent User Interfaces With Emotion Recognition, Fatma Nasoz

Electronic Theses and Dissertations

The focus of this dissertation is on creating Adaptive Intelligent User Interfaces to facilitate enhanced natural communication during the Human-Computer Interaction by recognizing users' affective states (i.e., emotions experienced by the users) and responding to those emotions by adapting to the current situation via an affective user model created for each user. Controlled experiments were designed and conducted in a laboratory environment and in a Virtual Reality environment to collect physiological data signals from participants experiencing specific emotions. Algorithms (k-Nearest Neighbor [KNN], Discriminant Function Analysis [DFA], Marquardt-Backpropagation [MBP], and Resilient Backpropagation [RBP]) were implemented to analyze the collected data signals …

Modified Sierpinski Fractal Antenna, Tripti Luintel

Electronic Theses and Dissertations

Fractal antennas have the potential to provide multi-band solution through the property of self similarity that the fractal shape possess. This thesis deals with some modifications of the original Sierpinski fractal patch antenna, providing additional parameters to optimize in order to get the required radiation characteristics. A systematic study of the original Sierpinski monopole was done to gain an insight on the operation and multi-band behavior of the antenna and a similar study was done to find out why the patch version of Sierpinski lacks multi-band behavior. A Sierpinski antenna is designed by merging a grid and the fractal restoring …