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Articles 172681 - 172710 of 198065

Full-Text Articles in Engineering

Electrocatalytic Oxidation Of Methanol On The Stearate Nickel L-B Film, Benzeng Hua, Wenyan Hu, Yanzhen Chen, Yanhong Zhang Aug 1997

Electrocatalytic Oxidation Of Methanol On The Stearate Nickel L-B Film, Benzeng Hua, Wenyan Hu, Yanzhen Chen, Yanhong Zhang

Journal of Electrochemistry

The stearate nickel L-B films is good electroacatlyst for the oxidation of methanol MeOH in alkaline. The electrochemical behaviors of stearate nickel L-B films is affected by the concentration of KOH. The rate of quantity of mickel ion and stearic acid in L-B films is 1∶1, which means that the nickel ion may exist in -COONi(OH) form. The electrocatalytic process is influenced by the concentration of OH-, it involves the penetration of MeOH into the films. The oxidative currents of MeOH are linearly dependent on the bulk concentration.


Study On Electrochemical Methods Of Controlled Convolution ——A Simple Electron Transfer Reaction Followed By A Homogeneous Catalytic Reaction(Ⅰ), Ming Ma, Naixian Xie, Qianlei Gao, Yue Zeng Aug 1997

Study On Electrochemical Methods Of Controlled Convolution ——A Simple Electron Transfer Reaction Followed By A Homogeneous Catalytic Reaction(Ⅰ), Ming Ma, Naixian Xie, Qianlei Gao, Yue Zeng

Journal of Electrochemistry

A simple electron transfer reaction followed by a homogeneous catalytic reaction is studied in this paper by three kinds of controlled convolution electrochemical experimental methods, which are the constant semi integral (CSI), linear semi integral sweep (LSIS) and linear semi differential sweep (LSDS). According to the three methods, the following equations can be obtained. With these equations, the theoretical curves of the above three methods can be computed. Experiments of the ferrocyanide ascorbic acid catalytic system have confirmed that kinetic rate constant in catalytic reaction is in good agreement with the previously reported values.


Preparation And Examination Of Planar Type Solid Oxide Fuel Cells, Yi Jiang, Jingwang Yan, Shizhong Wang, Chunying Yu, Wenzhao Li Aug 1997

Preparation And Examination Of Planar Type Solid Oxide Fuel Cells, Yi Jiang, Jingwang Yan, Shizhong Wang, Chunying Yu, Wenzhao Li

Journal of Electrochemistry

The solid oxide fuel cells of planar type (SOFC) have been developed after successfully preparing La0.8Sr0.2MnO3 cathodes and Ni-YSZ ceramic anodes on YSZ plates and solving the high temperature sealing technical problem. Examination of the single cells fabricated showed that the maximum power output at 950 ℃ for H2 as fuel and air as oxidant reached 0.12 W/cm2. It was found that the large polarization overpotential of the Ni-YSZ anode and the Ohmic losses of the cells were two main factors responsible for the relative low output power density.


The Electrode Process Of Some Organic Dyes Studied By Spectroelectrochemical Technique In Situ, Yinxuan Tang, Hangsheng Yang, Baoen Shen Aug 1997

The Electrode Process Of Some Organic Dyes Studied By Spectroelectrochemical Technique In Situ, Yinxuan Tang, Hangsheng Yang, Baoen Shen

Journal of Electrochemistry

Spectroelectrochemistry especially with in situ measurement in a cell provides a very useful mthodology for measuring the parameters of electrode process. In this paper, we report the determination of formal potentials, the number of electron transfer, the diffusion coefficient, the heterogeneous electron transfer rate constant and the transfer coefficient of some organic dyes (Methyelene blue, Neutral red, Indigo carmine) using spectroelectro chemical technique in situ.


Electrorheological Characters Of Polyaniline Suspensions, Guangyao Su, Deshu Gao, Changqing Zhang Aug 1997

Electrorheological Characters Of Polyaniline Suspensions, Guangyao Su, Deshu Gao, Changqing Zhang

Journal of Electrochemistry

Polyaniline (PAn) as the dispersive particles and insulating oil as the dispersive medium, the electrorheological fluid (ERF) is constituted. Relations between the factors of electric field strength (E), temperature (T) and the static yield stress (τS), current density (i) of ERF are investigated. The results show that the changes of τS and i with electric field intensity have emerged in the exponential relation, i.e, τS∝E0.7, i∝E2.18. Otherwise, when exert a constant voltage on ERF, owing to the polarization, the absorption of medium of ERF have taken place. Therefore, the attenuation rate …


Investigation On Electro Reduction Behaviour Of Copper Anodic Products In Concentrated Naoh Solutions Ⅱ. Electro Reduction Of Cu(Ⅱ) Products, Jianbo He, Hanhe Chen, Jianxin Lin Aug 1997

Investigation On Electro Reduction Behaviour Of Copper Anodic Products In Concentrated Naoh Solutions Ⅱ. Electro Reduction Of Cu(Ⅱ) Products, Jianbo He, Hanhe Chen, Jianxin Lin

Journal of Electrochemistry

Potentiostatic oxidation potentiodynamic or galvanostatic reduction methods have been used to study the cathodic reduction behaviour of various products anodically formed on the second stage of copper oxidation in concentrated NaOH solutions. Seven cathodic current peaks and the corresponding cathodic potential plateaus are observed on the potentiodynamic E/i curves and the galvanostatic E/t curves, respectively. In the negative potential scan, there are three couples of voltammetric peaks which have been attributed to the formation and reduction of CuO, Cu(OH)2 and Cu(Ⅱ) ion, respectively. The complicated mechanism for the electro formation of the three Cu(Ⅱ) species are discussed.


Preparation Of Pbo2/Ti Plate Electrode, Zhigang Shao, Baolian Yi, Xinge Zhang, Enjun Zhang Aug 1997

Preparation Of Pbo2/Ti Plate Electrode, Zhigang Shao, Baolian Yi, Xinge Zhang, Enjun Zhang

Journal of Electrochemistry

The perchlorate was made up of a lead dioxide plate elcetrode and an oxygen cathode. By measuring the flow capacity of cell gas in the cell, and by means of CV, SEM, XRD, the performances of the lead dioxide plate electrodes are evaluated. The influence of changes in the concentrations of electroplating solutions (F, HNO3, Bi3+, Ni2+, Fe3+ and surface active agent) is investigated. The results show that the concentrations of Fe3+ in the solutions must be lower 0.01 g/L, and the concentrations of HNO3 in the solutions are about 20 …


Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅲ. Improvement Of Artificially Imposed Solid Electrolyte Film On Cell Performance, Shuhua Ma, Xiabin Jing, Fosong Wang Aug 1997

Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅲ. Improvement Of Artificially Imposed Solid Electrolyte Film On Cell Performance, Shuhua Ma, Xiabin Jing, Fosong Wang

Journal of Electrochemistry

The improving effect of solid electrolyte film artificially imposed on carbon electrode was investigated. The result showed that both the charge/discharge capacity and first charge/discharge efficiency, to a certain extent, were enhanced, and the result also suggested the effectiveness of the substitution of the artificially imposed solid electrolyte film for the inherent passivating film which was formed on the surface of the carbon electrode while inserted in the electrolyte during charging or discharging. The Scanning Electron Microscope result displayed the compact and well-defined morphology of the artificially imposed crystalline film.


Studies On The Failure Modes Of Stationary Vrla Batteries, Yibo Tong, Xiangming Qiu Aug 1997

Studies On The Failure Modes Of Stationary Vrla Batteries, Yibo Tong, Xiangming Qiu

Journal of Electrochemistry

In order to improve the reliability and the quality of stationary valve-regulated lead-acid (VRLA) batteries, the failure modes of the stationary VRLA batteries which caused by the water loss and the thermal runaway are studied. The water loss may be solved by increasing the Oxygen-recombination efficiency, choosing the suitable grid material and the additives of megative paste, decreasing the corrosion of the positive plates. The thermal runaway may be solved by decreasing the inner ohmic resistance of VRLA batteries, improving the outside condition of batteries such as putting into the absorbing-heat material between the abtteries etc..


The Electrochemical Behavior And Deposited Mechanism Of Zn-Ni Alloy Codeposition, Jixun Wu, Yongqin Liu, Huimin Meng Aug 1997

The Electrochemical Behavior And Deposited Mechanism Of Zn-Ni Alloy Codeposition, Jixun Wu, Yongqin Liu, Huimin Meng

Journal of Electrochemistry

The electrochemical behavior of Zn-Ni alloy codeposition and concomitant hydrogen evolution have been studied in the chloride ammonia solution through the d-c electroplating method. Under the condition of the applied cathodic current density of 2A/dm2 , the AC impedance spectra have been measured. An equivalent circuit has been presented for the impedance study on the alloy codeposition.


Do Not As I Say And Not As I Do: The Problem Of Tritium, Ibpp Editor Aug 1997

Do Not As I Say And Not As I Do: The Problem Of Tritium, Ibpp Editor

International Bulletin of Political Psychology

The author discusses the manufacture and use of tritium for nuclear warheads.


A Parallel Genetic-Neuro Scheduler For Job-Shop Scheduling Problems, H. C. Lee, Cihan H. Dagli Aug 1997

A Parallel Genetic-Neuro Scheduler For Job-Shop Scheduling Problems, H. C. Lee, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Despite relentless efforts on developing new approaches, there are still large gaps between schedules generated through various planning systems, and schedules actually used in the shop floor environment. An effective schedule generation is a knowledge intensive activity requiring a comprehensive model of a factory and its environment at all times. There are four main difficulties that need to be addressed. First, job shop scheduling belongs to a class of NP-hard problems. Second, it is a highly constrained problem that changes from shop to shop. Third, scheduling decisions depend upon other decisions which are not isolated from other functions. Thus, it …


Orientation Relationships In The System Nb-Nbcr2, P. G. Kotula, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell Aug 1997

Orientation Relationships In The System Nb-Nbcr2, P. G. Kotula, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell

Materials Engineering

No abstract provided.


High-Frequency Response Of Atomic-Force Microscope Cantilevers, Joseph A. Turner, Sigrun Hirsekorn, Ute Rabe, Walter Arnold Aug 1997

High-Frequency Response Of Atomic-Force Microscope Cantilevers, Joseph A. Turner, Sigrun Hirsekorn, Ute Rabe, Walter Arnold

Department of Engineering Mechanics: Faculty Publications

Recent advances in atomic-force microscopy have moved beyond the original quasistatic implementation into a fully dynamic regime in which the atomic-force microscope cantilever is in contact with an insonified sample. The resulting dynamical system is complex and highly nonlinear. Simplification of this problem is often realized by modeling the cantilever as a one degree of freedom system. This type of first-mode approximation (FMA), or point-mass model, has been successful in advancing material property measurement techniques. The limits and validity of such an approximation have not, however, been fully addressed. In this article, the complete flexural beam equation is examined and …


Spectrally Sensitive Wavelet Analysis Of Multispectral Imagery For Object Detection, Samuel Peter Kozaitis, Ty Olmstead Aug 1997

Spectrally Sensitive Wavelet Analysis Of Multispectral Imagery For Object Detection, Samuel Peter Kozaitis, Ty Olmstead

Electrical Engineering and Computer Science Faculty Publications

We used a 3D wavelet denoising method to reduce noise from multispectral imagery so that small objects may be more readily detected. Our approach exploits the correlation between bands typically present in multispectral imagery. Using our approach, the resulting image generally consists of a weighted sum of both spectral bands and spatial frequencies. We found that we could generally increase the SNR of a multispectral image more than if the spectral bands were processed independently.


Modeling Improvements For Water Supply Forecasting In The Columbia River Basin, Daniel Albert Buller Aug 1997

Modeling Improvements For Water Supply Forecasting In The Columbia River Basin, Daniel Albert Buller

Dissertations and Theses

The purposes of this study were twofold. The first was to explore possible improvements that could be made over existing methods by applying alternative modeling approaches, including the one developed by Garen to forecast runoff volumes in the Columbia River at The Dalles, Oregon. The second was to use the Southern Oscillation as one of the variables to forecast spring and summer runoff and to evaluate whether this variable adds significant information early in the season before any snow has accumulated. The Columbia River basin's mountainous topography and northern latitude are ideally suited for water supply forecasting because much of …


Interferon Gamma (Ifn-Gamma) Is Necessary For The Genesis Of Acetylcholine Receptor-Induced Clinical Experimental Autoimmune Myasthenia Gravis In Mice., Balaji Balasa, Caishu Deng, Jae Lee, Linda M. Bradley, Dyanna K. Dalton, Premkumar Christadoss, Nora Sarvetnick Aug 1997

Interferon Gamma (Ifn-Gamma) Is Necessary For The Genesis Of Acetylcholine Receptor-Induced Clinical Experimental Autoimmune Myasthenia Gravis In Mice., Balaji Balasa, Caishu Deng, Jae Lee, Linda M. Bradley, Dyanna K. Dalton, Premkumar Christadoss, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Experimental autoimmune myasthenia gravis (EAMG) is an animal model of human myasthenia gravis (MG). In mice, EAMG is induced by immunization with Torpedo californica acetylcholine receptor (AChR) in complete Freund's adjuvant (CFA). However, the role of cytokines in the pathogenesis of EAMG is not clear. Because EAMG is an antibody-mediated disease, it is of the prevailing notion that Th2 but not Th1 cytokines play a role in the pathogenesis of this disease. To test the hypothesis that the Th1 cytokine, interferon (IFN)-gamma, plays a role in the development of EAMG, we immunized IFN-gamma knockout (IFN-gko) (-/-) mice and wild-type (WT) …


39th Rocky Mountain Conference On Analytical Chemistry Aug 1997

39th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Preliminary program and registration information for the 39th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 3-7, 1997.


Ccfss Technical Bulletin August 1997, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 1997

Ccfss Technical Bulletin August 1997, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.


Acuta Enews August 1997, Vol. 26, No. 8 Aug 1997

Acuta Enews August 1997, Vol. 26, No. 8

ACUTA Newsletters

In This Issue

26th Annual Conference: Highlights from Atlanta

Board Report

President's Message

Rains Came Down, Floods Came Up

Faster Internet Access Over Existing Wiring

Spotlight

Directory Update

Welcome New Members

DC at a Glance

ACUTA Event Calendar

Instant Info


Soft Computing Explains Heuristic Numerical Methods In Data Processing And In Logic Programming, Hung T. Nguyen, Vladik Kreinovich, Bernadette Bouchon-Meuiner Aug 1997

Soft Computing Explains Heuristic Numerical Methods In Data Processing And In Logic Programming, Hung T. Nguyen, Vladik Kreinovich, Bernadette Bouchon-Meuiner

Departmental Technical Reports (CS)

We show that fuzzy logic and other soft computing approaches explain and justify heuristic numerical methods used in data processing and in logic programming, in particular, M-methods in robust statistics, regularization techniques, metric fixed point theorems, etc.


How To Make World Wide Web Sites Faster And Easier To Use, Misha Kosheleva Aug 1997

How To Make World Wide Web Sites Faster And Easier To Use, Misha Kosheleva

Departmental Technical Reports (CS)

Working Notes of the AAAI Symposium on Frontiers in Soft Computing and Decision Systems, Boston, MA, November 8-10, 1997.

We propose a new idea of organizing Web sites so that the Web will be easier and faster to use.


Non-Equilibrium Thermodynamics Explains Semiotic Shapes: Applications To Astronomy And To Non-Destructive Testing Of Aerospace Systems, Roberto A. Osegueda, Carlos M. Ferregut, Mary J. George, Jose M. Gutierrez, Vladik Kreinovich Aug 1997

Non-Equilibrium Thermodynamics Explains Semiotic Shapes: Applications To Astronomy And To Non-Destructive Testing Of Aerospace Systems, Roberto A. Osegueda, Carlos M. Ferregut, Mary J. George, Jose M. Gutierrez, Vladik Kreinovich

Departmental Technical Reports (CS)

Proceedings of the International Conference on Intelligent Systems and Semiotics (ISAS'97), National Institute of Standards and Technology Publ., Gaithersburg, MD, 1997, pp. 378-382.

Celestial bodies such as galaxies, stellar clusters, planetary systems, etc., have different geometric shapes (e.g., galaxies can be spiral or circular, etc.). Usually, complicated physical theories are used to explain these shapes; for example, several dozen different theories explain why many galaxies are of spiral shape. Some rare shapes are still difficult to explain.

It turns out that to explain these "astroshapes", we do not need to know the details of physical equations: practically all the shapes …


Field Evaluation Of Ultrasonic Method For Assessing Well Seals, Nazli Yesiller, Craig H. Benson, Tuncer B. Edil Aug 1997

Field Evaluation Of Ultrasonic Method For Assessing Well Seals, Nazli Yesiller, Craig H. Benson, Tuncer B. Edil

Civil and Environmental Engineering

Field tests were conducted in three boreholes using an ultrasonic testing method to evaluate its ability to assess contact between the seal and riser (casing). The ultrasonic method is used inside the riser without disturbing the riser, seal, or formation soil. The risers were 50-mm-diameter (2-inch) Schedule 40 steel pipes that are used for ground water monitoring wells. Different types of seals were placed around the risers and defects were purposely introduced in the seals to test the ultrasonic method. The ultrasonic response changed as the neat-cement seals cured or hydration of the bentonite seals changed. When adequate moisture was …


Bulletin - August, 1997, Civil Aviation Medical Association Aug 1997

Bulletin - August, 1997, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A twelve page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.


Towards Computers Of Generation Omega - Non-Equilibrium Thermodynamics, Granularity, And Acausal Processes: A Brief Survey, Misha Kosheleva, Vladik Kreinovich Aug 1997

Towards Computers Of Generation Omega - Non-Equilibrium Thermodynamics, Granularity, And Acausal Processes: A Brief Survey, Misha Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

Proceedings of the International Conference on Intelligent Systems and Semiotics (ISAS'97), National Institute of Standards and Technology Publ., Gaithersburg, MD, 1997, pp. 383-388.

Nowadays, we are using mainly computer of fourth generation, and we are designing fifth-generation computers. It is reasonable to ask: what is the perspective? What will the computers of generation omega look like?

--As the speed of data processing increases, we face a natural limitation of causality, according to which the speed of all processes is limited by the speed of light.

--Lately, a new area of acausal (causality violating) processes has entered mainstream physics.

This …


Multi-Resolution Data Processing: It Is Necessary, It Is Possible, It Is Fundamental, Scott A. Starks, Vladik Kreinovich, Alex Meystel Aug 1997

Multi-Resolution Data Processing: It Is Necessary, It Is Possible, It Is Fundamental, Scott A. Starks, Vladik Kreinovich, Alex Meystel

Departmental Technical Reports (CS)

Experience shows that many data processing problems are difficult to solve, and some of these problems have even been proven to be computationally intractable. Human experts successfully solve many such problems by using a hierarchical, multi-resolution approach. These multi-resolution methods are, in several cases, provably optimal. However, due to the computational intractability of the problem itself, the multi-resolution approach can only work if the systems that we are analyzing are themselves hierarchical. We show that, first, due to (inevitable) measurement inaccuracies, an arbitrary input data is consistent with the hierarchical model, and second, that in many cases, the actual physical …


Using Geotextiles For Feeding And Traffic Surfaces, Larry W. Turner Aug 1997

Using Geotextiles For Feeding And Traffic Surfaces, Larry W. Turner

Agricultural Engineering Extension Publications

Mud robs Kentucky beef and dairy producers of performance from their cattle herds in winter and spring. To help avoid the problems associated with mud and reduced performance, producers should consider using concrete pads or lower-cost all-weather surfaces wherever animals congregate (e.g., feeding areas, animal traffic areas, and loafing areas). Although concrete is probably the most desirable surface for durability and low maintenance, an all-weather surface can be constructed of geotextile fabric, rock, and fine surface cover for less than one-third of the cost of concrete. Rock over bare soil in Kentucky requires approximately 12 inches of depth for stability, …


Gallium Desorption Behavior At Algaas/Gaas Heterointerfaces During High-Temperature Molecular Beam Epitaxy, K. Mahalingam, D. L. Dorsey, K. R. Evans, Rama Venkat Aug 1997

Gallium Desorption Behavior At Algaas/Gaas Heterointerfaces During High-Temperature Molecular Beam Epitaxy, K. Mahalingam, D. L. Dorsey, K. R. Evans, Rama Venkat

Electrical & Computer Engineering Faculty Research

A Monte Carlo simulation study is performed to investigate the Ga desorption behavior during AlGaAs-on-GaAs heterointerface formation by molecular beam epitaxy. The transients in the Ga desorption rate upon opening the Al shutter are shown to be associated with the concurrent reduction in the V/III flux ratio. Monte Carlo simulations employing a constant V/III flux ratio yield a “steplike” variation in the Ga desorption rate with the resulting interfaces closer in abruptness to the ideal AlGaAs-on-GaAs interface. Further details on the stoichiometry of the interface and its relationship with predicted Ga desorption profiles is presented.


A Unified Green's Function Analysis Of Complicated Dfb Lasers, Jim D. Freeze, Michael A. Jensen, Richard H. Selfridge Aug 1997

A Unified Green's Function Analysis Of Complicated Dfb Lasers, Jim D. Freeze, Michael A. Jensen, Richard H. Selfridge

Faculty Publications

An efficient full-wave analysis technique for one-dimensional optical domains, known as the recursive Green's function method (RGFM), is presented for evaluation of distributed feedback (DFB) laser cavities with arbitrary material profiles. The method first constructs the Green's function of an inhomogeneous domain and subsequently uses Green's theorem to determine the laser optical field, lasing wavelength, and threshold gain. The technique is applied to investigate the performance of three DFB laser structures: a chirped-grating configuration, a modulated stripe width design, and a reduced duty cycle complex-coupled device. These structures are evaluated in terms of their single-mode lasing behavior and the uniformity …