Engineering Commons^™

Overview Of Acousto-Optic Bistability, Chaos, And Logical Applications, Monish Ranjan Chatterjee, Erol Sonmez

Electrical and Computer Engineering Faculty Publications

An overview is presented of the key results in the field of acousto-optic bistability in the past two decades. It is shown that the basic acousto-optic bistable device may be described as a nonlinear dynamical system which satisfies a quadratic map. Thereafter, details are presented of several analytical methods, computer modeling approaches, including the SPICE circuit modeling technique, and experiments that have been used to understand the phenomenon.

Extensions to logical and digital applications are also discussed.

A New Linear-Programming Based Admissible Heuristic For Cost-Based Abducaton, Muhamed Salah-Al-Din Hefny

Archived Theses and Dissertations

No abstract provided.

Recommending Egyptian Guidelines For Managing Construction And Demolition (C&D) Waste, Marwa Saad Moussa Alansary

Archived Theses and Dissertations

No abstract provided.

Integration Of A Statcom And Battery Energy Storage, Zhiping Yang, Shen Chen, Lin Zhang, Stan Atcitty, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

The integration of an energy storage system, such as battery energy storage (BESS), into a FACTS device can provide dynamic decentralized active power capabilities and much needed flexibility for mitigating transmission level power flow problems. This paper introduces an integrated StatCom/BESS for the improvement of dynamic and transient stability and transmission capability; compare the performance of the different FACTS/BESS combinations, and provide experimental verification of the proposed controls on a scaled StatCom/BESS system

A Method For Evaluating The Dielectric Properties Of Composites Using A Combined Embedded Modulated Scattering And Near-Field Microwave Nondestructive Testing Technique, Dana M. Hughes, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Investigation into the derivation of the dielectric property of a material with an embedded modulated PIN diode-loaded dipole is described, using an open-ended rectangular waveguide as the irradiating source. Previous measurements of the curing of a mortar specimen show the sensitivity of this combined technique and its potential for inspecting composite structures. Modification of previous algorithms for back calculating the dielectric properties of a material with a conductor backing is considered. The modification would involve replacing the reflection at the conductor with the reflection at a modulated dipole antenna. For this, comparisons between the reflection coefficients of the dipole antenna …

Needs Assessment For Local Roads And Streets 2001, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

The objective of this study was to investigate the needs of and resources available to local public agencies to construct and maintain their transportation infrastructure. Components of the infrastructure included in this study are roads, bridges and culverts, traffic and traffic safety, and operational and administrative costs. The results of the study indicate there exists a significant shortfall in funding in most of these areas.

Bs News

Building Services Engineering

No abstract provided.

Scattering Of Elastic Waves In Heterogeneous Media With Local Isotropy, Joseph A. Turner, Phanidhar Anugonda

Nebraska Center for Materials and Nanoscience: Faculty Publications

The scattering of elastic waves in heterogeneous media is discussed. Explicit expressions are derived for the attenuation of longitudinal and transverse elastic waves in terms of the statistics of the density and Lame´ parameter fluctuations. The derivation is based upon diagrammatic methods with the problem posed in terms of the Dyson equation. The Dyson equation is solved for the mean field response. The results are given here in a straightforward manner, in which the attenuations reduce to simple integrals on the unit circle. The medium is assumed statistically homogeneous and statistically isotropic. This model, with assumed local isotropic properties, is …

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange Vs. Lattice Oxygen Diffusion, Kevin Huang, John B. Goodenough

Faculty Publications

The oxygen permeation fluxes from p′_O2 to pⁿ_O2 (p′_O2>pⁿ_O2) across cobalt-containing perovskite ceramic membranes La_1−xSr_xCoO_3−δ and SrCo_0.8Fe_0.2O_3−δ were measured by gas chromatography as functions of oxygen chemical potential gradient, temperature, thickness, and catalytic activity on the surface. Power indexes 0.5>n>0 for uncatalyzed La_1−xSr_xCoO_3−δ and 1>n>0.5 for SrCo_0.8Fe_0.2O_3−δ were obtained when J_O2 vs. p′ⁿ_O2−p'′ⁿ_{O2 …}

Overview Of Fuzzy Logic, Mohamed Trabia

Mechanical Engineering Faculty Presentations

The presentation includes a brief introduction to fuzzy logic and fuzzy logic controllers. These concepts are illustrated by an example of an autonomous vehicle controller.

Comparison Of Two Distributed Fuzzy Logic Controllers For Flexible-Link Manipulators, Linda Z. Shi, Mohamed Trabia

Mechanical Engineering Faculty Presentations

The paper suggests that fuzzy logic controllers present a computationally efficient and robust alternative to conventional controllers. The paper presents two possible structures for the distributed fuzzy logic controller of a single-link flexible manipulator. A linear quadratic regulator method is used to prove the effectiveness of fuzzy logic controllers.

Design Of Fuzzy Logic Controllers For Optimal Performance, Mohamed Trabia

Mechanical Engineering Faculty Presentations

While fuzzy logic controllers are generally robust, the performance of a system whose behavior is not well understood, or that has a large number of coupled inputs and outputs, may be less than optimal. In this paper, nonlinear programming techniques are used to improve the performance of a fuzzy logic controller for navigating an autonomous vehicle.

A Neural Network-Based Vision System For Automated Separation Of Onion From Clod Using Mechanical Harvester, Demian Morquin

Theses and Dissertations - UTB/UTPA

A neural network classifier for separating clods from onions during harvesting has been developed. The separator consists of a multi-layer feedforward network that maps textural features computed from gray-scale images of onions and clods into the correct object. Texture features were computed from co-occurrence matrices that specify the spatial relationship of pixel values in an image. The textural features selected for this application consist of homogeneity, contrast, variance, and energy. The network was trained using the back-propagation algorithm. Based on the textural features classification, the effect of changing the network configuration on separation effectiveness was investigated. Factors including network topology …

Decomposition Of Relations: A New Approach To Constructive Induction In Machine Learning And Data Mining -- An Overview, Marek Perkowski, Stanislaw Grygiel

Electrical and Computer Engineering Faculty Publications and Presentations

This is a review paper that presents work done at Portland State University and associated groups in years 1989 - 2001 in the area of functional decomposition of multivalued functions and relations, as well as some applications of these methods.

Shear Wave Velocity Profiles At Sites Liquefied By The 1999 Kocaeli, Turkey Earthquake, Brady R. Cox

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper presents shear wave velocity profiles for 15 sites liquefied by the 1999 Kocaeli, Turkey earthquake. These profiles are used in order to evaluate each liquefaction site by the simplified shear wave velocity procedure. This procedure allowed for the identification of a potentially liquefiable region within the subsurface at each site. Locating this region at each site allowed for the separation of soils that were too stiff to liquefy from soils that were soft enough to liquefy. Once these soft regions had been identified, they were evaluated to separate granular soils expected to liquefy, from fine-grained soils expected not …

Design And Analysis For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Darrell Pepper, Randy Clarksean

Fuels Campaign (TRP)

UNLV investigators will evaluate and select a process for the melt casting of metallic fuel pins that contain volatile actinides. This work will be performed with the guidance of Argonne National Laboratory (ANL) engineers to insure that their knowledge and experience benefits the project. The research to be conducted during year one will center on selecting, evaluating, and modeling potential alternatives to the traditional injection casting process used at ANL. Processing conditions will be analyzed, basic models utilized, and detailed heat and mass transfer models will be developed to analyze the most promising processes. The goal of the first year …

An Electronically Tunable Resonator For Noise Control, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

Many engineering systems create unwanted noise that can be reduced by the careful application of engineering noise controls. When this noise travels down tubes and pipes, a tuned resonator can be used to muffle noise escaping from the tube. The classical examples are automobile exhaust and ventilation system noise. In these cases where a narrow frequency band of noise exists, a traditional engineering control consists of adding a tuned Helmholtz resonator to reduce unwanted tonal noise by reflecting it back to the source (Temkin, 1981). As long as the frequency of the unwanted noise falls within the tuned resonator frequency …

A New Portable, Pc Based, Usb Powered Dynamic Signal Analyzer, Charles Birdsong, George Ma, James Nieters, Justin Tang, Caine Yu

Mechanical Engineering

A new USB powered portable 4-channel real time Dynamic Signal Analyzer and its automotive applications are described. The design and architecture lend themselves to real time NVH measurements and analysis in the field, in-vehicle or on production lines. Built-in signal conditioning provides for direct sensor power while the embedded DSP provides for signal processing on-board. Performance and implementation of FFT, digital filters and order analyses are presented.

University Of Texas Austin: Stanford Space Systems Program, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "University of Texas Austin: Stanford Space Systems Program" from April 30, 2001.

Very-Low-Specific-Resistance Pd/Ag/Au/Ti/Au Alloyed Ohmic Contact To P Gan For High-Current Devices, V. Adivarahan, A. Lunev, M. Asif Khan, J. Yang, Grigory Simin, M. S. Shur, R. Gaska

Faculty Publications

We report on Pd/Ag/Au/Ti/Au alloyed metallic contact to pGaN. An 800 °C anneal for 1 min in flowing nitrogen ambient produces an excellent ohmic contact with a specific contact resistivity close to 1×10⁻⁶ Ω cm² and with good stability under high current operation conditions. This high-temperature anneal forms an alloy between Ag,Au, and pGaN resulting in a highly p-doped region at the interface. Using x-ray photoelectron spectroscopy and x-ray diffractionanalysis, we confirm that the contact formation mechanism is the metal intermixing and alloying with the semiconductor.

Aspect Sensitivity Measurements Of Polar Mesosphere Summer Echoes Using Coherent Radar Imaging, P. B. Chilson, T.-Y. Yu, R. D. Palmer, S. Kirkwood

Department of Electrical and Computer Engineering: Faculty Publications

The Esrange VHF radar (ESRAD), located in northern Sweden (67.88) N, 21.10- E), has been used to investigate polar mesosphere summer echoes (PMSE). During July and August of 1998, coherent radar imaging (CRI) was used to study the dynamic evolution of PMSE with high temporal and spatial resolution. A CRI analysis provides an estimate of the angular brightness distribution within the radar’s probing volume. The brightness distribution is directly related to the radar reflectivity. Consequently, these data are used to investigate the aspect sensitivity of PMSE. In addition to the CRI analysis, the full correlation analysis (FCA) is used to …

Visiting Committee Review: Spacecraft Program, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Visiting Committee Review: Spacecraft Program" from April 26, 2001.

Feed-Forward Compensation Scheme For Feedback Circuits, Venugopal Gopinathan, Vladimir I. Prodanov

Electrical Engineering

A feed-forward compensated negative feedback circuit comprises an operational amplifier having an inverting and a non-inverting input and an output. A feedback element is connected between the output of the operational amplifier and its inverting input to form a negative feedback loop. The inverting input of the op-amp is driven with a first transconductance amplifier which produces an output current proportional to an input voltage. A feed-forward transconductance amplifier receives the input voltage and produces an inverted output current proportional to the input voltage. A feed-forward current is injected at the output of the operational amplifier. By providing at the …

Electrode Modification Using An Unzippable Polymer Paste, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A paste is described for capping electrodes with an oxide free metal layer incorporating a solvent, an unzippable polymer and particles. The electrode could be an interconnect such as a C4 bump. A method for forming a coating and for testing integrated circuit chips is also described. The invention overcomes the problem of interconnecting Pb containing electrodes that are covered with an insulating oxide on integrated circuit chips by coating the Pb containing electrode with Au to provide an oxide free surface for testing and interconnection.

Ultra High Density Storage Media And Method Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A storage media for storing information having a substrate. The substrate has an upper surface and a molecular weight greater than 5,000. Preferably the material is a polymer. The material has a plurality of piles of molecular chains in selected areas formed by pushing the molecular chains of the material on its upper surface to the selected area mechanically with a mechanical tool. The piles represent written information. The mechanical tool is preferably an atomic force microscope. Another aspect of the present invention is a method for storing information having the steps of selecting a material substrate having an upper …

The Importance Of Site Surveys In Florida's Pv Buildings Program, Florida Solar Energy Center, Kevin Lynn

FSEC Energy Research Center®

One of the goals of the Florida PV Buildings Program is to ensure that only quality utility-interactive PV systems are installed in the state. One important component of the Program is the site survey. The purpose of the site survey is to inspect the potential location for PV system before beginning construction, ensuring it is a sensible place to install it. The purpose of this paper is to introduce the method used by this Program and to present some examples that will demonstrate why it is important.

Apr 2001, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Camp Creek Swap Meet Public Relations Get Fordson Running

Multimodal Fusion Of Polynomial Classifiers For Automatic Person Recognition, Charles C. Broun, Xiaozheng Zhang

Electrical Engineering

With the prevalence of the information age, privacy and personalization are forefront in today's society. As such, biometrics are viewed as essential components of current and evolving technological systems. Consumers demand unobtrusive and noninvasive approaches. In our previous work, we have demonstrated a speaker verification system that meets these criteria. However, there are additional constraints for fielded systems. The required recognition transactions are often performed in adverse environments and across diverse populations, necessitating robust solutions.

There are two significant problem areas in current generation speaker verification systems. The first is the difficulty in acquiring clean audio signals (in all environments) …

Terrain Analysis Using Digital Elevation Models, David G. Tarboton, Daniel Ames

Civil and Environmental Engineering Faculty Publications

No abstract provided.

Observations Of Volcanic Clouds In Their First Few Days Of Atmospheric Residence: The 1992 Eruptions Of Crater Peak, Mount Spurr Volcano, Alaska, William I. Rose, Gregg J. Bluth, David J. Schneider, Gerald G. J. Ernst, Colleen M. Riley, Lydia J. Henderson, Robert G. Mcgimsey

Department of Geological and Mining Engineering and Sciences Publications

Satellite SO2 and ash measurements of Mount Spurr’s three 1992 volcanic clouds are compared with ground‐based observations to develop an understanding of the physical and chemical evolution of volcanic clouds. Each of the three eruptions with ratings of volcanic explosivity index three reached the lower stratosphere (14 km asl), but the clouds were mainly dispersed at the tropopause by moderate to strong (20–40 m/s) tropospheric winds. Three stages of cloud evolution were identified. First, heavy fallout of large (>500 μm) pyroclasts occurred close to the volcano (vent) during and immediately after the eruptions, and the cloud resembled an advected …