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Articles 175051 - 175080 of 197998

Full-Text Articles in Engineering

An Indirect Electrochemical Oxidation Of Toluene──Anodic Oxidation Of Mn(Ⅱ) On The Lead Electrode, Zhonghua Wang, Qingmin Hua, Guacai Chen, Zhongquan Wang, Yunan Qiu, Xingguo Yan May 1995

An Indirect Electrochemical Oxidation Of Toluene──Anodic Oxidation Of Mn(Ⅱ) On The Lead Electrode, Zhonghua Wang, Qingmin Hua, Guacai Chen, Zhongquan Wang, Yunan Qiu, Xingguo Yan

Journal of Electrochemistry

The electrochemical oxidation of Mn(Ⅱ) to Mn(Ⅱ) in concentrated H2SO4 (2 ~ 8 mol⋅L-1) at lead electrode has been studied. It is found that the electrode surface is oxidized to PbO2 in a direct electrochemical reaction, then PbO2 formed reacts with Mn(Ⅱ) in a chemical reaction. Some effects involves current density, concentration of H2SO4, temperature and conversionwere evaluated. The rule of electrogenerated Mn(Ⅲ) in flow electrolysis cell were determined at several conditions. The current efficiency at greater than 90% is obtained in general.


Electrochemically Modified Glassy Carbon Electrode And Determination Of Copper By Anodic Stripping Voltammetry, Jinrui Xu, Yie Liu, Xiurun Zhuang, Tomoo Miwa, Toyohide Takeuchi May 1995

Electrochemically Modified Glassy Carbon Electrode And Determination Of Copper By Anodic Stripping Voltammetry, Jinrui Xu, Yie Liu, Xiurun Zhuang, Tomoo Miwa, Toyohide Takeuchi

Journal of Electrochemistry

This paper reported the glassy carbon electrode modified by cyclic voltammetrybetween -0.1 and +1.5 V (vs. SCE) in an aqueous solution containing catechol, for maldehyde and talium hydroxide. The modified electrode can be applied to the determination of copper(Ⅱ) in water, and its sensitivity is about 35 times higher than that of unmedified glassy carbon electrode, The quantitative limit with this modified electrode is 0.1 ng/ml.


Photoelectrochemical And Spectroelectrochemical Studies Oniron Oxide Ultrafine Particles, Maizhi Yang, Yongjun Ji, Wen Zhang, Shengmin Cai, Xiaojiang Lu, Zhongqun Tian, Jin Luo May 1995

Photoelectrochemical And Spectroelectrochemical Studies Oniron Oxide Ultrafine Particles, Maizhi Yang, Yongjun Ji, Wen Zhang, Shengmin Cai, Xiaojiang Lu, Zhongqun Tian, Jin Luo

Journal of Electrochemistry

In this paper, Raman spectra, photocurrent and the UV-VIS reflectance aremeasured for studying the α-Fe2O3 ultrafine particles adsorbed on Pt electrode. The blue shifts of Raman peaks demonstrate the size quantization effect for the particles of 50 nm in diameter ascompared with the bulk material. With the changing of the potential, the photocurrent decrcases as the UV-VIS reflectance increases, and vice-versa. Therefore, the potential not only affects the hargetransfer direcdtion in the interface of electrode/redox couple, but also influences the light absortion onthe surface of particles. According to the results of photoelectrochemistry, we suggest that the cathodic …


A Sutface-Enhanced Raman Spectroscopic Study On The Inhibition Mechanism Of Bmat On Stainless Steel In Hydrochloric Acid Solutions, Yinghua Zha, Baoming Wei, Zhongqun Tian, Changjian Lin May 1995

A Sutface-Enhanced Raman Spectroscopic Study On The Inhibition Mechanism Of Bmat On Stainless Steel In Hydrochloric Acid Solutions, Yinghua Zha, Baoming Wei, Zhongqun Tian, Changjian Lin

Journal of Electrochemistry

The absorbtion of some nitrogen and sulfur compounds such as BMAT on 18-8stainless steel (SS) in 0.5% HCl were investigated by surface enhanced Raman scattering (SERS) spectroscopy. The SERS spectra of BMAT adsorbed on SS were measured using a SS electro deposited with discontinuous silvet micro-islands. The results show that the inhibitor, BMAT, is chemisorbed on the SS surface through the N atom. Under the influence of π-electron interaction, BMAT can be adsorbed on SS surface at an angle. The allyls in BMAT molecules play the role of steric hindrance in the inhibition effect.


Horseradish Peroxidase/Poly-O-Phen Ylenediamine Mem Brane Electrode: Preparation And Properties, Dong Wei, Huihuang Wu May 1995

Horseradish Peroxidase/Poly-O-Phen Ylenediamine Mem Brane Electrode: Preparation And Properties, Dong Wei, Huihuang Wu

Journal of Electrochemistry

A horseradish peroxidase (HRP)/poly-o-phenylenediamine (PPD) membrane electrode was prepared by electropolymerization of o-phenylenediamine on glassy carbon in pH 7.0 phosphate buffer, the process of the enzyme immobilization was studied. The enzyme electrode obtained exhibits the activity to catalyze the electroreduction of hydrogen peroxide in the absence of any electron transfer mediator. The red uction reaction occurs in the potential range of PPD redoxprocess, it was believed that the polymer participates in electron transfer of the enzyme. The enzyme reaction kinetics at rotating HRP/PPD electrode was analysed, and the factors influencing kinetic parameters were discussed.


The Electrochemical Reduction Of 2-Ethylanthraquinone (2eaq), Yaobin Zhu May 1995

The Electrochemical Reduction Of 2-Ethylanthraquinone (2eaq), Yaobin Zhu

Journal of Electrochemistry

The process of electrochemical reduction of 2EAQ in DMSO is studied using CVand ESR methods in this work, Pt, Pd and some implanted materials are used as electrodes. The quasi-rever-sible property of two electron transfer steps and their following homogeneous chemical reactions are illustrated. The mechanism of the electrochemical red uction of 2EAQ and the kinetic parameters of the related steps are obtained. Having measured the influence of water content in the system, the effect of the proton donor is discussed. After comparising the experimental results with each other these experiments gives us the idea that the replacement of metal …


The Reduction Of Oxygen To Hydrogen Peroxide At The Poly(O-Phenylenediamine)-Filmed Electrode, Zhaoe Lu, Tiangeng Zhong, Guanyong Zhang May 1995

The Reduction Of Oxygen To Hydrogen Peroxide At The Poly(O-Phenylenediamine)-Filmed Electrode, Zhaoe Lu, Tiangeng Zhong, Guanyong Zhang

Journal of Electrochemistry

The poly(o-phenylenediamine) (PPD) filmed graphite electrode was formed by electro-polymerization of o-phenylenediamine in acidified (pH=1) 0.2 mol·L-1 Na2SO4 solution using the cyclic voltammetric methed. The catalytic effect of the electrcareduction of oxygen in acid olution was demonstrated by the voltammogram of the electrode in the oxygen saturated acid solutionof Na2SO4. The current efficiency of the reduction of oxygen to hydrogen peroxide was determined by the electrolysis in a divided cell under the condition of constant current. The various effectsinfluencing the accmulation of H2O2 in the catholyte were discussed.


Studies On Coordination Behavior Of Dimethyl Sulfoxide In Complex Of Rare Earth With Cryptand, Shichang Liu, Tianpei Zhu May 1995

Studies On Coordination Behavior Of Dimethyl Sulfoxide In Complex Of Rare Earth With Cryptand, Shichang Liu, Tianpei Zhu

Journal of Electrochemistry

Electrochemical reduction reaction in the course of the titration of Eu(2.2.2) and Eu(2.2) using strong bonding solvent, DMSO, in C2H4Cl2 has been investigated by cyclic voltammetry. The greater the concentration of strong bonding solvent, the more negative the half-wave potentials for the reduction reaction are. The coordination number of Eu(2.2.2) and Eu(2.2) which are 2 and 3 respectively, with DMSO can be calculated, according to the relations between half-wave potentials and the variety of concentration of DMSO.


Effects Of Hydrogen On Inp Light-Emitting Devices Etched In A Methane-Hydrogen Environment, Patricia Beck, Dennis J. Derickson, Forrest Kellert, Tim Bagwell May 1995

Effects Of Hydrogen On Inp Light-Emitting Devices Etched In A Methane-Hydrogen Environment, Patricia Beck, Dennis J. Derickson, Forrest Kellert, Tim Bagwell

Electrical Engineering

Research has been conducted on the physical damage and hydrogenation effects during RF plasma exposure and epitaxial growth in the III-V material system. Device consequences of this damage or chemical alteration have received less attention, particularly in active light emitting devices. This paper discusses these effects for lasers and edge emitting light-emitting diodes (EELEDs) which use a ridge waveguide structure. By using analysis techniques such as SIMS we have concluded that methane-hydrogen reactive ion etching of InP induces hydrogen levels in an active device which are high enough to significantly alter the device properties. The decrease in light output is …


A Vhdl Design Of A Reconfigurable Cache Memory System, Tiffany M. Brooks May 1995

A Vhdl Design Of A Reconfigurable Cache Memory System, Tiffany M. Brooks

Honors Capstone Projects and Theses

No abstract provided.


Time Dependence Of Multiply Scattered Diffuse Ultrasound In Polycrystalline Media, Joseph A. Turner, Richard L. Weaver May 1995

Time Dependence Of Multiply Scattered Diffuse Ultrasound In Polycrystalline Media, Joseph A. Turner, Richard L. Weaver

Department of Engineering Mechanics: Faculty Publications

Time domain results are presented for the multiply scattered longitudinal intensity backscattered from a polycrystalline medium. The results are solutions to the ultrasonic radiative transfer equation (URTE), the derivation of which is based upon radiative transfer theory. Unlike steady-state solutions obtained previously, time domain solutions will more closely correspond to experiments that use tone burst sources. This paper is concerned with the time dependence of the backscattered longitudinal intensity from a polycrystalline medium excited by a normally incident longitudinal wave idealized as an impulsive deposition of energy. It is shown that multiple scattered effects become significant at times on the …


First Line Supervisor Perceptions: The Effectiveness Of Specific Safety Training Materials, Cynthia Houlson May 1995

First Line Supervisor Perceptions: The Effectiveness Of Specific Safety Training Materials, Cynthia Houlson

Graduate Research Papers

The problem of this study was to determine whether first line supervisors, who have been exposed specifically to Safety Focus Topics, perceived them as an effective tool in filling their role as a safety trainer.


Bandwidth And Additive Bandwidth Of Graphs, Maria Kujawski May 1995

Bandwidth And Additive Bandwidth Of Graphs, Maria Kujawski

Honors Capstone Projects and Theses

No abstract provided.


Testability Design And Testability Analysis Of A Cube Calculus Machine, Lixin Zhou May 1995

Testability Design And Testability Analysis Of A Cube Calculus Machine, Lixin Zhou

Dissertations and Theses

Cube Calculus is an algebraic model popular used to process and minimize Boolean functions. Cube Calculus operations are widely used in logic optimization, logic synthesis, computer image processing and recognition, machine learning, and other newly developing applications which require massive logic operations. Cube calculus operations can be implemented on conventional general-purpose computers by using the appropriate "model" and software which manipulates this model. The price that we pay for this software based approach is severe speed degradation which has made the implementation of several high-level formal systems impractical. A cube calculus machine which has a special data path designed to …


Water Quality Model For South Slough, Coos Bay, Oregon, Holly Kay Juza May 1995

Water Quality Model For South Slough, Coos Bay, Oregon, Holly Kay Juza

Dissertations and Theses

The South Slough Estuary is located off Coos Bay along the southern coast of Oregon. It is divided into two channels that meet and continue to Coos Bay at the Charleston Harbor. There are six major contributing streams to South Slough. After rainfall events, the level of coliform bacteria in the slough increases because of stream bacteria loading. This is due to cattle grazing in the drainage areas, failed septic systems from private homes, and sewage sludge applied to the County landfill, which drains into the slough. The Oregon Health Division has enforced a Sanitation Management Plan for Commercial Shellfish …


Numerical Study Of Granular Soil Behavior Using Random Arrays Of Elastic Ellipsoids, Xiaoshan Lin May 1995

Numerical Study Of Granular Soil Behavior Using Random Arrays Of Elastic Ellipsoids, Xiaoshan Lin

Civil Engineering ETDs

For the purpose of improving computer simulation of granular materials in the framework of the Discrete Element Method (DEM), 2-D and 3-D discrete element models using random arrays of elastic ellipsoids have been developed.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 11, Number 5, May 1995, College Of Engineering And Computer Science, Wright State University May 1995

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 11, Number 5, May 1995, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.


Supersonic, Turbulent Flow Computation And Drag Optimization For Axisymmetric Afterbodies, Russell M. Cummings, H. T. Yang, Y. H. Oh May 1995

Supersonic, Turbulent Flow Computation And Drag Optimization For Axisymmetric Afterbodies, Russell M. Cummings, H. T. Yang, Y. H. Oh

Aerospace Engineering

The compressible, turbulent flow about an axisymmetric body was numerically studied using the MacCormack unsplit explicit algorithm applied to the mass-average Navier-Stokes equations solved in conjunction with the k-ε turbulence model of Jones and Launder. Numerical predictions of total body drag (pressure drag, skin friction drag, and base drag) were made for an axisymmetric body six diameters in length, with and without a boattail. Surface pressures and viscous layer profiles are compared with available wind tunnel data and are found to be in good agreement for both geometries. The Golden Section optimization method was used to optimize the body …


Distortion And Evolution Of A Localized Vortex In An Irrotational Flow, Joseph F. Lingevitch, Andrew J. Bernoff May 1995

Distortion And Evolution Of A Localized Vortex In An Irrotational Flow, Joseph F. Lingevitch, Andrew J. Bernoff

All HMC Faculty Publications and Research

This paper examines the interaction of an axisymmetric vortex monopole, such as a Lamb vortex, with a background irrotational flow. At leading order, the monopole is advected with the background flow velocity at the center of vorticity. However, inhomogeneities of the flow will cause the monopole to distort. It is shown that a shear‐diffusion mechanism, familiar from the study of mixing of passive scalars, plays an important role in the evolution of the vorticity distribution. Through this mechanism, nonaxisymmetric vorticity perturbations which do not shift the center of vorticity are homogenized along streamlines on a Re1/3 time scale, much faster …


Relationship Of The Second Order Nonlinear Optical Coefficient To Bandgap In Inorganic Non-Centrosymmetric Crystals, A. G. Jackson, M. Ohmer, S. R. Leclair May 1995

Relationship Of The Second Order Nonlinear Optical Coefficient To Bandgap In Inorganic Non-Centrosymmetric Crystals, A. G. Jackson, M. Ohmer, S. R. Leclair

Mechanical and Materials Engineering Faculty Publications

The purpose of this paper, is to provide a means of estimating and comparing the wavelength conversion efficiency (figure of merit, FOM) of new nonlinear materials knowing only their bandgap. The approach for the estimates is trend analysis of existing data1-28 for the second order nonlinear coefficient, x(2)ijk, or dij =x(2)ijk/2, the index of refraction n, and the bandgap E. No underlying physical basis for the result will be presented. The result of this trend analysis, in the form of plots of x(2) vs E and FOM vs E …


Simulation Of The Growth Of Cvd Films, Jacob J. Thiart, Vladimir Hlavacek, Hendrik J. Viljoen May 1995

Simulation Of The Growth Of Cvd Films, Jacob J. Thiart, Vladimir Hlavacek, Hendrik J. Viljoen

Papers in Materials Science

Chemical vapor deposition (CVD) is the preferred method of manufacture for solid films used in many industrially important thin and thick film applications. Requirements for the physical, mechanical and electrical properties of these films are becoming increasingly difficult to achieve, and deposition morphology plays an important role in this regard. Recently, we proposed a continuum model describing the evolution of a gassolid interface during atmospheric pressure CVD (Viljoen er al., 1994). A linear stability analysis (LSA) was used to determine the effect of reactor conditions on planar growth stability. The present paper discusses numerical solution of this model, and uses …


Advanced Rover Chassis, Eric Alan Poulson, Collin Lewis, Todd Graves May 1995

Advanced Rover Chassis, Eric Alan Poulson, Collin Lewis, Todd Graves

Undergraduate Honors Capstone Projects

Background:

The six wheeled rover vehicle detailed in this design is intended as an upgrade test bed for the sensor array and autonomous navigation algorithms in use by Utah State University's Center for Self-Organizing and Intelligent Systems (CSOIS). The CSOIS's sensor suite can successfully detect and avoid unnavigable obstacles up to five vehicle lengths in front of the vehicle. The center presently uses a modified RC type chassis and only supports two wheel drive. This chassis was adequate to bring the CSOIS's algorithms to a proof-of-principles state, but in order to place the system in any practical application, a full …


Lake Evaporation: A Model Study, Jumah Amayreh May 1995

Lake Evaporation: A Model Study, Jumah Amayreh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Reliable evaporation data are an essential requirement in any water and/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured using advanced research instruments (Bowen Ratio and Eddy Correlation). Actual over-lake evaporation and weather data measurements were used to understand the mechanism of evaporation in the lake, determine lake-related parameters (such as roughness lengths, heat storage, net radiation, etc.), and …


Vibration Analysis Of A Split Path Gearbox, Timothy L. Krantz, Majid Rashidi May 1995

Vibration Analysis Of A Split Path Gearbox, Timothy L. Krantz, Majid Rashidi

Scholarship Collection

Split path gearboxes can be attractive alternatives to the common planetary designs for rotorcraft, but because they have seem little use, they are relatively high risk designs. To help reduce the risk of fielding a rotorcraft with a split path gearbox, the vibration and dynamic characteristics of such a gearbox were studied. A mathematical model was developed by using the Lagrangian method, and it was applied to study the effect of three design variables on the natural frequencies and vibration energy of the gearbox. The first design variable, shaft angle, had little influence on the natural frequencies. The second variable, …


The Effects Of A Pathway-In-The-Sky Display On Performance Of A Two Axis Tracking Task By Instrument Rated Pilots, Leonard W. Hennessy, Iii May 1995

The Effects Of A Pathway-In-The-Sky Display On Performance Of A Two Axis Tracking Task By Instrument Rated Pilots, Leonard W. Hennessy, Iii

Master's Theses - Daytona Beach

This study was founded on the premise that airplane cockpit operations, while generally safe and relatively efficient, can be made even more so by employing instrument displays which are potentially more intuitive than existing displays. A low fidelity flight simulator was used to conduct an experiment comparing the performance of twenty-four instrument rated pilot subjects on a two axis tracking task (an Instrument Landing System Approach) under three instrument display conditions: (1) conventional instruments (INST); (2) a Pathway-in-the-Sky (PITS) display; and (3) a combination of the two (BOTH). The primary hypothesis, that pilot performance using the PITS and BOTH display …


Dynamic Simulation Of General Aviation Cabin Environments And Occupant Restraint Systems, Mark A. Shilladay May 1995

Dynamic Simulation Of General Aviation Cabin Environments And Occupant Restraint Systems, Mark A. Shilladay

Master's Theses - Daytona Beach

After a five year study of General Aviation (GA) accidents, the National Transportation Safety Board (NTSB) has concluded that aircraft cabin environments place the occupant at high risk of suffering severe injuries in an emergency crash situation. Studies of Federal Aviation Administration (FAA) seat tests were used to form the basis of a computer analysis to address dynamic cabin environments. In this effort a simplified system of masses, springs, and dampers are used to simulate the more complex configuration of cabin structure, seat, pilot, and restraints on a personal computer. The primary objective of this study is to accurately simulate …


A Summative Evaluation Of Flightsafety International's Computer Assisted Instruction Known As "Principles Of Troubleshooting", Willie Don Middlebrooks May 1995

A Summative Evaluation Of Flightsafety International's Computer Assisted Instruction Known As "Principles Of Troubleshooting", Willie Don Middlebrooks

Master's Theses - Daytona Beach

The objective of this experimental research was to ascertain if cognitive skills developed by the "Principles of Troubleshooting" (POT) educational course improved aircraft fault diagnostic ability in aircraft maintenance trainees. Sixty randomly chosen Embry-Riddle Aeronautical University (ERAU) students served as control and experimental subjects with the POT course as the independent variable. Because random assignment was possible, a posttest-only control group design was used. Thirty ERAU maintenance trainees who had received basic and advanced ERAU fault diagnostic training were administered the POT course. A practical test administered to both groups using two tailed t tests for independent means indicated improvement …


Acuta Enews May 1995, Vol. 24, No. 5 May 1995

Acuta Enews May 1995, Vol. 24, No. 5

ACUTA Newsletters

In This Issue

Board report

President's message

DC at a glance

Benchmarks for your telecom operation

From ACUTA Headquarters


Fuzzy Logic For Digital Phase-Locked Loop Filter Design, Daniel J. Simon, Hossny El-Sherief May 1995

Fuzzy Logic For Digital Phase-Locked Loop Filter Design, Daniel J. Simon, Hossny El-Sherief

Electrical and Computer Engineering Faculty Publications

The problem of robust phase-locked loop design has attracted attention for many years, particularly since the advent of the global positioning system. This paper proposes and demonstrates the use of a fuzzy PLL to estimate the time-varying phase of a sinusoidal signal. It is shown via simulation results that fuzzy PLL's offer performance comparable to analytically derived PLL's (e.g. Kalman filters and H∞ estimators) when the phase exhibits high dynamics and high noise. The fuzzy PLL rules are optimized using a gradient descent method and a genetic algorithm


Power Bus Decoupling On Multilayer Printed Circuit Boards, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, David M. Hockanson May 1995

Power Bus Decoupling On Multilayer Printed Circuit Boards, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, David M. Hockanson

Electrical and Computer Engineering Faculty Research & Creative Works

Guidelines for the selection and placement of decoupling capacitors that work well for one-sided or two-sided printed circuit boards are not appropriate for multilayer boards with power and ground planes. Boards without internal planes take advantage of the power bus inductance to help decouple components at the higher frequencies. An effective decoupling strategy for multilayer boards must account for the low inductance and relatively high capacitance of the power bus.