Engineering Commons^™

Adaptive Resonance Associative Map, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This article introduces a neural architecture termed Adaptive Resonance Associative Map (ARAM) that extends unsupervised Adaptive Resonance Theory (ART) systems for rapid, yet stable, heteroassociative learning. ARAM can be visualized as two overlapping ART networks sharing a single category field. Although ARAM is simpler in architecture than another class of supervised ART models known as ARTMAP, it produces classification performance equivalent to that of ARTMAP. As ARAM network structure and operations are symmetrical, associative recall can be performed in both directions. With maximal vigilance settings, ARAM encodes pattern pairs explicitly as cognitive chunks and thus guarantees perfect storage and recall …

Remote Detection Of Acoustic Boundaries Using Radiation Imaging Operators, Richard E. Dubroff, Md. Ishfaqur Raza, Thomas J. Herrick

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we present an acoustic imaging operator. This operator is based upon combining the material boundary conditions at an acoustic boundary and the radiation boundary conditions associated with one way wave propagation. Numerical examples, using the second-order imaging operator, are presented in order to demonstrate the applicability of this method to the detection of two-dimensional boundaries.

Master Of Science Degree Programs Computer Information Systems, Management Information Systems 1995, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.

Electrochemical Determination Of The Diffusion Coefficient Of Hydrogen Through An Lani4.25Al0.75 Electrode In Alkaline Aqueous Solution, G. Zheng, Branko N. Popov, Ralph E. White

Faculty Publications

Theconstant potential and constant current discharge techniques were used todetermine the hydrogen diffusion coefficients in an LaNi_4.25Al_0.75 electrode. The valuesobtained were 2.97 × 10^–11 and 3.30 × 10^–11 cm²/s, respectively. The advantages and disadvantages of these two techniques are discussed.

Hydrogen-Atom Direct-Entry Mechanism Into Metal Membranes, G. Zheng, Branko N. Popov, Ralph E. White

Faculty Publications

The hydrogen-atom direct-entry mechanism is used to explain why the steady-state hydrogen permeation current density through a metal membrane is directly proportional to the cathodic current density, i_c, and is independent of the membrane thickness when i_c is small.

The Effect Of Current And Nickel Nitrate Concentration On The Deposition Of Nickel Hydroxide Films, Christopher C. Streinz, Andrew P. Hartman, Sathya Motupally, John W. Weidner

Faculty Publications

An electrochemical quartz crystal nanobalance (EQCN) has been utilized to measure the mass of Ni(OH)₂ films electrochemically deposited from Ni(NO₃)₂ solutions. The objective of this work was to quantify electrochemical deposition as a function of deposition conditions. The changing mass recorded on the EQCN was demonstrated to be the result of Ni(OH)₂ deposition. Deposited mass was observed to increase proportionally with applied charge as suggested by previous investigators. Most significantly, the rate of deposition was found to decrease more than an order of magnitude as the Ni(NO₃)₂ concentration increased from 0.2 to …

Proton Diffusion In Nickel Hydroxide Films: Measurement Of The Diffusion Coefficient As A Function Of State Of Charge, Sathya Motupally, Christopher C. Streinz, John W. Weidner

Faculty Publications

Electrochemical impedance spectroscopy (EIS) was used to measure the solid-state diffusion coefficient of protons in nickel hydroxide films at room temperature as a function of state of charge (SOC). A model for the complex faradaic impedance of the nickel hydroxide active material is presented and used to extract the diffusion coefficient of protons from the EIS data. Impedance data over a range of frequencies can be used to extract a constant diffusion coefficient without the knowledge of the initial mobile proton concentration or the form of the charge-transfer kinetic expression. The proton diffusion coefficient is a strong function of SOC …

A Boundary-Layer Model Of A Parallel-Plate Electrochemical Reactor For The Destruction Of Nitrates And Nitrites In Alkaline Waste Solutions, Shailesh Prasad, John W. Weidner, Andrew E. Farell

Faculty Publications

Electrochemical processes appear to be attractive for treating low level nuclear wastes. The development of a simple divided electrochemical-cell model operating in a batch mode, used for the reduction of nitrates and nitrites from nuclear wastes, is presented. This model, based on a boundary-layer approach, is simple and yet encompasses the key features of a previously developed distributed-parameter model that includes diffusion, migration, and convection as the flux components. Because it dramatically reduces computation time, this boundary-layer model is well suited for use in a complex interactive flowsheet model and for optimization studies. The boundary-layer model is used to predict …

The Effect Of Temperature And Ethanol On The Deposition Of Nickel Hydroxide Films, Christopher C. Streinz, Sathya Motupally, John W. Weidner

Faculty Publications

The objective of this work was to determine the effect of the temperature and the ethanol content of the Ni(NO₃)₂ solution on: (i) the efficiency of electrochemical deposition of nickel hydroxide; and (ii) the molecular weight of the deposited film. An electrochemical quartz crystal nanobalance (EQCN) was used to measure the mass of films electrochemically deposited from Ni(NO₃)₂ solutions and constant current discharges were used to determine the electrochemical capacity of the films. The data indicates that increasing the temperature increases both the efficiency of the deposition reaction and the …

Electrowinning Of Non-Noble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes I. Theoretical, Mahmoud M. Saleh, John W. Weidner, Badr G. Ateya

Faculty Publications

A mathematical model is developed to simulate the electrowinning of non-noble metals (e.g., Zn, Cr) within flow-through porous electrodes under the conditions of simultaneous evolution of hydrogen gas bubbles. The results of the model are presented as a function of several dimensionless groups representing kinetics, mass transfer, ohmic resistance, and gas bubbles. These coupled, nonlinear effects are investigated by examining the distributions of the metal reduction and hydrogen evolution currents, coulombic efficiency of the metal electrowinning reaction, and gas void fractions under a series of limiting conditions. The gas bubbles accentuate the nonuniform distribution of the potential and …

Electrowinning Of Non-Noble Metals With Simultaneous Hydrogen Evolution At Flow-Through Porous Electrodes Ii. Experimental, Mahmoud M. Saleh, John W. Weidner, Bahgat E. Ei-Anadouli, Badr G. Ateya

Faculty Publications

This paper presents an interpretation of the experimental results obtained on the electrowinning of zinc at a flow-through porous electrode in light of a mathematical model which was presented in Part I. The process is accompanied by simultaneous hydrogen evolution within the electrode, which increases the pore electrolyte resistivity and decreases the coulombic efficiency. We measured polarization curves, coulombic efficiencies, and current distributions under various conditions of zincate concentrations, flow rates, cell current, and electrode thickness. Reasonable agreement between the measured and predicted current distributions was obtained only under conditions of high electrolyte flow rates, low cell currents, and thinner …

A Parallel-Plate Electrochemical Reactor Model For The Destruction Of Nitrate And Nitrite In Alkaline Waste Solutions, D. H. Coleman, Ralph E. White, D. T. Hobbs

Faculty Publications

A parallel-plate electrochemical reactor model with multiple reactions at both electrodes and anolyte and catholyte recirculation tanks was modeled for the electrochemical destruction of nitrate and nitrite species in an alkaline solution. The model can be used to predict electrochemical reaction current efficiencies and outlet concentrations of species from the reactor, given inlet feed conditions and cell operating conditions. Also, predictions are made for off-gas composition and liquid-phase composition in the recirculation tanks. The results of case studies at different applied potentials are shown here. At lower applied potentials, the model predictions show that the destruction process is more energy …

Mathematical Modeling Of A Nickel-Cadmium Cell: Proton Diffusion In The Nickel Electrode, Pauline De Vidts, Ralph E. White

Faculty Publications

In this paper we present a mathematical model of a sealed nickel-cadmium cell that includes proton diffusion and ohmic drop through the active material in the nickel electrode. The model is used to calculate sensitivity coefficients for various parameters in the model. These calculations show that the discharge voltage of the cell is affected mostly by the kinetics of the nickel reaction. Toward the end of discharge, proton diffusion also becomes important, because the proton diffusion process affects the active material utilization significantly. During charge, the cell voltage is mainly affected by the kinetics of the nickel reaction until the …

Mathematical Modeling For The Discharge Of A Metal Hydride Electrode, Pauline De Vidts, Javier Delgado, Ralph E. White

Faculty Publications

No abstract provided.

A Diamond Thin Film Flow Sensor, Sacharia Albin, John C. Hagwood, John B. Cooper, David L. Gray, Scott D. Martinson, Michael A. Scott

Electrical & Computer Engineering Faculty Publications

We present the results of theoretical modeling and experimental testing of a diamond thin film sensor for flow studies. It is shown that the high thermal conductivity of a diamond film can enhance the frequency response of the flow sensor. One-dimensional heat diffusion equation was solved using the finite difference method for determining the frequency response. Two different sensor structures were analyzed: a Ni film on a quartz substrate (Ni/Q) and an intermediate layer of diamond film between the Ni film and quartz substrate (Ni/D/Q). The theoretical model predicts a frequency response for the Ni/D/Q sensor higher than that of …

Image Classification Using Textural Neural Networks, Edit J. Kaminsky, Herb S. Barad

Electrical Engineering Faculty Publications

This paper presents backpropagation neural networks that utilize texture information to accurately classify photographic images. Training with minimum sets is shown to yield excellent results.

Image Classification Using Version Spaces, Edit J. Kaminsky, Willie G. Brown

Electrical Engineering Faculty Publications

This paper presents the candidate elimination implementation of the version space strategy for classification of photographic data. It is shown that very accurate classification is easily achieved and that only a small number of training samples are needed to generate the rules.

Maximum Rate Of Change Of The Differential Reflection Phase Shift With Respect To The Angle Of Incidence For Light Reflection At The Surface Of An Absorbing Medium: Èrratum, R. M.A. Azzam, A. M. El-Saba

Electrical Engineering Faculty Publications

No abstract provided.

Vortex Lattice Symmetry And Electronic Structure In Yba2cu3o7, Bernhard Keimer, Wan Y. Shih, Ross W. Erwin, Jeffrey W. Lynn, Fatih Dogan, Ilhan A. Aksay

Materials Science and Engineering Faculty Research & Creative Works

We report a small angle neutron scattering study of the vortex lattice in YBa₂Cu₃O₇ in magnetic fields of 0.5≤ H ≤5 T applied along and close to the c axis. Over the entire field range, the vortices form an oblique lattice with two nearly equal lattice constants and an angle of 73° between primitive vectors. Numerical calculations suggest that variations of the superconducting order parameter near the vortex core are important in stabilizing this structure. An analysis that accounts for the fourfold symmetry of the vortex core qualitatively explains both the symmetry and the orientation …

United States Patent: Ellipsometer, John A. Woollam, Blaine D. Johs, David W. Doerr, Reed A. Christenson

Department of Electrical and Computer Engineering: Faculty Publications

To sense characteristics of a sample, an ellipsometer includes a pivotal diffraction grating positioned to receive white light from the analyzer without further focusing of the light after the light leaves the sample. The diffraction grating is focused on the sensor at a predetermined angle with a precision of at least plus or minus one-half degree using an alignment-sensing means positioned between the analyzer and diffraction grating. The sensor includes an aperture through which the incident beam of light is transmitted, light-sensitive areas on opposite sides of said sensor and a comparator for comparing the signal from said light-sensitive areas. …

Radiative Transfer Of Ultrasound, Joseph A. Turner, Richard L. Weaver

Department of Engineering Mechanics: Faculty Publications

A radiative transfer equation is used to model the diffuse multiple scattering of ultrasound in a medium containing discrete random scatterers. An assumption of uncorrelated phases allows one to write an equation of energy balance for the diffuse intensity. This ultrasonic radiative transfer equation contains single-scattering and propagation parameters that are calculated using the elastic wave equation. Polarization effects are included through the introduction of an elastodynamic Stokes vector which contains a longitudinal Stokes parameter and four shear Stokes parameters similar to the four Stokes parameters used in optical radiative transfer theory. The theory is applied to a statistically homogeneous, …

Travelling Wave Electrode Optimization For High Speed Electro-Optic Modulators Using The Fourier Series Method, W. Boyu, X. Guangjun, Xiaomin Jin

Electrical Engineering

The performance of Z-cut Mach-Zehnder high speed LiNbO₃ amplitude modulators with a CPW traveling wave electrode, has been analyzed and optimally designed in detail by the Fourier series method. The effect of electrode and buffer layer thickness on the electric field distribution in the substract, effective micro- wave refractive index and characteristic impedance of CPW electrode, are discussed. Calculation shows that increasing the thickness of the electrode and SiO₂ buffer layer can improve the phase velocity mismatch between electric and optical waves, and the drive power required by the modulator with thin buffer layer and thick electrode is …

A Guide To Floodplain Cattle Fencing, Department Of Agriculture, Western Australia, Main Roads, Western Australia

Animal production and livestock published reports

A seminar and workshop was held at Fitzroy Crossing in October 1993 to address the consequences of flooding to landholders and communities.

Damage to flood plain fencing was identified as one of the major concerns to landholders.

An outcome from the workshop was the decision to draw on local knowledge and collate information on options for fence and floodgate designs.

This information was to be made available to land holders and other interested parties - hence this publication.

In Vitro Activities Of 2,2'-Bipyridyl Analogs Against Mycobacterium Leprae, Arvind Madhav Dhople, Maria Antonia Ibáñez, Anita A. Dhople

Biomedical Engineering and Sciences Faculty Publications

In vitro susceptibility of Mycobacterium leprae to two bipyridyl analogs was studied by using two biochemical parameters to measure the metabolic activity of the organism. VUF-8514 at 0.16 μg/ml, but not VUF-8842, completely inhibited the metabolic activity of M. leprae, and the action was bactericidal. When compared to rifampin (MIC 0.3 μg/ml), VUF-8514 was equally bactericidal against M. leprae.

Acuta Enews December 1994, Vol. 23, No. 12

ACUTA Newsletters

In This Issue

Board report

President's message

George Mason University becomes "virtual campus"

Phone fraud at Salve Regina

Campus-wide network at James Madison

From ACUTA Headquarters

Sorption Of Chlorinated Organic Compounds By Sedimentary Rocks, Paul M. Mcginley, S. Kesaraju, Ronald D. Gruzesky

KWRRI Research Reports

The sorption of dichlorobenzene and trichlorobenzene on carbonate and shale rocks collected in Kentucky demonstrate that rock organic matter content is a good indicator of sorptive reactivity in rock systems. Although this is similar to soil systems, significant differences between sorption in rock and soil systems exist. Sorption isotherms on these rocks are nonlinear and sorption can be an order of magnitude higher than predicted using correlations from soils and their organic matter content. This sorption reaction could lead to significant concentration tailing during contaminant cleanup. Experimental elution of trichloroethylene from rock filled columns verified that cleanup times might be …

Instability In Self-Pulsation In Laser Diodes And Its Effect On All-Optical Synchonization, Jonathan Hyland, Gerald Farrell

Articles

The effect of short- and long-term frequency instability in self pulsation on all-optical synchronization using a twin-section laser diode is experimentally investigated. Short-term frequency instability broadens the unlocked full width at half maximum (FWHM) of the fundamental of the rf spectrum of the self-pulsating laser diode. We show experimentally that the value of the unlocked FWHM, and thus the level of short-term instability, has a direct effect on the optical power required to maintain synchronization. A novel means of reducing the FWHM is presented based on a reflective transmission line stub connected to the absorber of the twin-section self-pulsating laser …

Development Of A Highway Safety Management System For Indiana: Phase 1, Omar Farooq, Kumares C. Sinha, John Nagle, Dwayne Stanley James, Yi Jiang

JTRP Technical Reports

This report presents the work plan for the development of a highway safety management system for Indiana. It identifies major activities and responsibilities for the development and implementation of a formal, statewide, interactive safety decision-making process. The safety management system of Indiana is perceived as a continuous process of considering all opportunities to improve highway safety in all phases of highway planning, design, construction, maintenance and operation. The primary emphasis is on coordination of activities at various levels and on the development of a common information data base that can be used for selecting and implementing effective highway safety strategies …

Optical-Fiber Preamplifiers For Ladar Detection And Associated Measurements For Improving The Signal-To-Noise Ratio, Michael S. Salisbury, Paul F. Mcmanamon, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

In an effort to increase achievable postdetection signal-tonoise ratios (SNRs) of continuous-wave, 1-gm all-solid-state ladar systems, a prototype rare-earth-doped optical-fiber amplifier has been included in the optical return signal path of both a heterodyne and a directdetection ladar system. We provide numerical predictions for SNR increases according to our previously developed theory. We also detail our experimental efforts and provide the results of SNR measurements for four distinct cases: direct ladar detection with and without a fiber amplifier, and heterodyne ladar detection with and without a fiber amplifier. Experimentally measured increases in SNRs for ladar systems incorporating an optical-fiber amplifier …

An Overview Of Flexible Ac Transmission Systems, P. Asare, T. Diez, A. Galli, E. O'Neill-Carillo, J. Robertson, R. Zhao

Department of Electrical and Computer Engineering Technical Reports

FACTS or "flexible AC transmission systems" is a term that has been suggested for the use of solid state devices to control bulk power flow in transmission systems. The Electric Power Research Institute supported this idea, and many researchers have invested efforts on the value and potential of FACTS. At this time, it appears that the main value of FACTS lies in improving transmission capability; increasing the flexibility of power flow control (e.g., for wheeling or for economic dispatch); for controlling voltage (and var flow); and possibly additional advantages in lower voltage systems (e.g., distribution systems). This report is an …