Engineering Commons^™

Studies On Electrodeposition Of Rare Earth Metals And Their Alloys In Molten Salts, Qiqin Yang

Journal of Electrochemistry

The cyclic voltammetry, convolution voltammetry, potentiostatic electrolysis and open circuit potential time curve after electrolysis, current time curve at potential step, potential time curve at current step, X-ray diffraction, EDAX, electron probe microanalysis were used to investigate the electrode processes of the reduction of rare earth ions on inert electrodes and alloying electrodes in molten chlorides and fluorides. The free energies of formation for the intermetallic compounds, the diffusion coefficients of rare earth ions in the melt, the diffusion coefficients of rare earth atoms in the alloy phases were determined. The alloys of rare earth with iron, cobalt, nickel, copper, …

Surface Modification Of Molten Carbonate Fuel Cell Anode, Baizeng Fang, Xinyu Liu, Xindong Wang, Shuzhen Duan

Journal of Electrochemistry

In this study, the anode material of molten carbonate fuel cell was modified by the deposition of niobium on nickel surface. The results of polarization experiments reveal that the corrosion resistant properties as well as electrocatalytic activity have been improved greatly.

Study Of Electrodepositing Bright Tin Cobalt Zinc Alloy From Weak Acid Solution, Zhengzhong Zuo, Runxiang Hou, Shaochun Xia

Journal of Electrochemistry

A new process of electrodeposting bright Tin Cobalt Zinc alloy from weak acid solution is proposed in this paper. The solution compositions and operating conditions are Na₃C₆H₅O₇·2H₂O 100～150, Na₂EDTA·2H₂O 20～30, SnCl₂·2H₂O 15～20, CoSO₄·72H₂O 25～35, ZnCl₂ 15～20 g·L^-1; stabilizer WDZ-160～100, brightener WDZ-215～20 mL·L^-1; pH=4～6, D_K=0.5～5.0 A·dm^-2, T=5～35 ℃. A bright Sn-Co-Zn deposit having Co about 0.5～3.5% and Zn about 1～10% is produced. The effects of bath compositions on Co or …

Electroluminescence Of Photoelectrochemically Etched N+-Si, Guozheng Li, Chengqian Zhang, Xiumei Yang

Journal of Electrochemistry

Porous silicon with micrometer size pores, which is made on n⁺-Si by photoelectrochemically etched, has electroluminescent property. Each monochromic intensity and wavelength range of luminescent spectra depend on polarized potential. The intersity and the stability of cathodic electroluminescence is high than those of anodic one. Voltammetric behavior before quenching indicated that the electrochemical reactions of some surface species are involved in except the reduction of S₂O₈^2-, which leads to radiative recombination. The energy band diagram based on n⁺-Si(E_g=1.1 eV)/PS(E_g=1.8 eV) junction is proposed.

Effects Of Curvature On The Electrochemical Behaviors Of Tubular Electrode, Yirong Wu, Zhenghao Wang

Journal of Electrochemistry

The convective diffusion equation of tubular electrode was solved with the implicit finite difference numerical method. Comparing with the electrochemical behaviors of channel electrode, the behaviors of tubular electrode were analysised. The effects of curvature on the electrochemical behaviors of tubular electrode and the limit of applying Levich approximation to tubular electrode were discussed.

Mechanism And Texture Of Ni-Mo Alloy Electrodeposition, Ling Huang, Shukai Xu, Jaoning Tang, Fangzu Yang, Shaomin Zhou

Journal of Electrochemistry

Ni-Mo alloy deposits with (111) preferred orientation was obtained in a solution of 0.22 mol/L NiSO₄·6H₂O, 0.06 mol/L Na₂MoO₄·2H₂O and 0.3 mol/L Na₃C₆H₅O₇·2H₂O in temperature from 25℃ to 50℃, and current densities ranged from 10 mA·cm^-2 to 30 mA·cm^-2. The electrodeposition of Ni-Mo alloy was studied by cylic voltammetry and potential step experiment. It was shown that Ni-Mo alloy is formed by mechanism involving progressive nucleation followed by three dimensional growth of the metal centres. The complex …

Study On The Preparation, Properties And Applications Of The Polymer/Graphite Composite Electrode, Guohua Chen, Jinrui Xu

Journal of Electrochemistry

The graphite AS composite electrodes, which show high electric conductivity, high mechanical strength and operationl stability, were prepared by filling and extruding the AS copolymer with graphite powder. It exhibited a substantial hydrogen overvoltage and small residual current in different electrolytes, as compared with glassy carbon electrode. The electrode was applied to the determination of traces of Pb²⁺ in mineral water, Ag⁺ in waste water and In³⁺, Cu²⁺, Pb²⁺, Cd²⁺ in zinc ore, and showed high stability, reproducibility and selectivity. Owing to the existence of abundant polar functioal groups on the …

1997 - The Second Annual Symposium Of Student Scholars

Symposium of Student Scholars Program Books

The full program book from the Second Annual Symposium of Student Scholars, held on May 23rd, 1997. Includes abstracts from the presentations and posters.

Settlements Due To Arid Collapsible Soils, Heather L. Devine

Dissertations and Theses

The arid alluvial deposits common to the western United States frequently undergo moderate to severe collapse when wetted that can threaten or destroy the stability of structures that are founded on such soils. Additionally, in some areas collapse has been known to occur due to overburden stresses alone. As development expands in these areas a method to estimate the degree of this collapse is essential.

Current settlement methods are reviewed and evaluated as they apply to collapsible soils, providing a basis for the development of a proposed settlement method for determining collapse. To aid in the determining the basis for …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 13, Number 5, May 1997, 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.

Predictable File Access Latency For Multimedia, Dan Revel, Crispin Cowan, Dylan Mcnamee, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Multimedia applications are sensitive to I/O latency and jitter when accessing data in secondary storage. Transparent adaptive prefetching (TAP) uses software feedback to provide multimedia applications with file system quality of service (QoS) guarantees. We are investigating how QoS requirements can be communicated and how they can be met by adaptive resource management. A preliminary test of adaptive prefetching is presented.

Single Row Routing: Theoretical And Experimental Performance Evaluation, And New Heuristic Development, David A. Hysom

Computer Science Theses & Dissertations

The Single Row Routing Problem (SRRP) is an abstraction arising from real-world multilayer routing concerns. While NP-Complete, development of efficient SRRP routing heuristics are of vital concern to VLSI design. Previously, researchers have introduced various heuristics for SRRP; however, a comprehensive examination of SRRP behavior has been lacking.

We are particularly concerned with the street-congestion minimization constraint, which is agreed to be the constraint of greatest interest to industry. Several theorems stating lower bounds on street congestion are known. We show that these bounds are not tight in general, and argue they may be in error by at least 50% …

Santa Clara Magazine, Volume 39 Number 1, Spring 1997, Santa Clara University

Santa Clara Magazine

6 - BLUE SKY INVASION Searching for the American Dream, aerospace workers transform the Santa Clara Valley. By David Beers '79, Illustrations by Dug Waggoner

15 - SEEING IS BELIEVING Professor Sally Wood develops software to help students visualize basic engineering concepts. By Laura Trujillo '92

18 - CONFRONTING THE SCARS OF CENTURIES A legal challenge to California's Proposition 209 is the latest round in a long- running debate over affirmative action. By Margaret M. Russell

26 - SHADOWY ALLIANCE A recent expose alleging CIA links to the crack cocaine epidemic in California's inner cities raises questions about responsibility and …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 13, Number 4, April 1997, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Feedback Control Solutions To Network Level User-Equilibrium Real-Time Dynamic Traffic Assignment Problems, Pushkin Kachroo, Kaan Ozbay

Electrical & Computer Engineering Faculty Research

A new method for performing dynamic traffic assignment (DTA) is presented which is applicable in real time, since the solution is based on feedback control. This method employs the design of nonlinear H∞ feedback control systems which is robust to certain class of uncertainties in the system. The solution aims at achieving user equilibrium on alternate routes in a network setting.

Mlpq: A Linear Constraint Database System With Aggregate Operators, Yiming Li

School of Computing: Dissertations, Theses, and Student Research

In this project report, I will discuss a Multiple Linear Programming Query (MLPQ) system and the theoretical background of this system.The MPLQ system is developed to solve some realistic problems involving both linear programming (UP) techniques and linear constraint databases (LCDBs) theory. The MLPQ system is aimed at providing a mechanism of bridging these two important areas. system basically consists of three parts which are a linear constraint database, an LP solver, and an interface between the LCDB and the LP solver. The LCDB of the MLPQ system contains multiple linear programming problems. The LP solver used in the MPLQ …

High Resolution Wavelength Modulation Spectroscopy For Precise Gaseous Characterization, Audra Michiele Bullock

Electrical & Computer Engineering Theses & Dissertations

Wavelength modulation spectroscopy is a highly sensitive, non-intrusive technique for probing gaseous species. Parameters such as velocity, density, and temperature can be measured and monitored with a high degree of precision. In addition, with the use of this technique multiple molecular species may be identified with a single laser probe. This measurement technique utilizes the well-known principles of modulation absorption spectroscopy in a novel way.

The research focuses on harmonic detection and the advantages gained by performing detection at higher harmonics, those greater than the commonly used second harmonic. We show that there is an increase in the sensitivity to …

Investigating The Use Of Kalman Filtering Approaches For Dynamic Origin-Destination Trip Table Estimation, Pushkin Kachroo, Kaan Ozbay, Arvind Narayanan

Electrical & Computer Engineering Faculty Research

This paper studies the applicability of Kalman filtering approaches for network wide traveler origin-destination estimation from link traffic volumes. The paper evaluates the modeling assumptions of the Kalman filters and examines the implications of such assumptions.

Three-Dimensional Aerodynamic Design Optimization Using Discrete Sensitivity Analysis And Parallel Computing, Amidu Olawale Oloso

Mechanical & Aerospace Engineering Theses & Dissertations

A hybrid automatic differentiation/incremental iterative method was implemented in the general purpose advanced computational fluid dynamics code (CFL3D Version 4.1) to yield a new code (CFL3D.ADII) that is capable of computing consistently discrete first order sensitivity derivatives for complex geometries. With the exception of unsteady problems, the new code retains all the useful features and capabilities of the original CFL3D flow analysis code. The superiority of the new code over a carefully applied method of finite-differences is demonstrated.

A coarse grain, scalable, distributed-memory, parallel version of CFL3D.ADII was developed based on "derivative stripmining". In this data-parallel approach, an identical copy …

Physical And Managed Risk Of Nuclear Waste, Lennart Sjöberg, Britt-Marie Drottz-Sjöberg

RISK: Health, Safety & Environment (1990-2002)

The authors describe their work on the perceived risk of nuclear waste in Sweden. Three levels of waste were studied, and comparisons between the perceptions of the public, politicians and nuclear experts are made.

Book Review Of Alla Yaroshinskaya, Chernobyl: The Forbidden Truth, John M. Gleason

RISK: Health, Safety & Environment (1990-2002)

Review of the book: Alla Yaroshinskaya, Chernobyl: The Forbidden Truth (Michele Kahn & Julia Sallabank, trans. University of Nebraska Press 1995). Introduction, foreword, list of illustrations, photographs. ISBN 0-8032-4912-8. [136 pp. Cloth $25.00; Paper $10.00. 312 N. 14th Street, Lincoln NE 68588-0484.]

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 13, Number 3, March 1997, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

A Comparison Of Circular Error Probable Estimators For Small Samples, Charles E. Williams

Theses and Dissertations

Several previous studies investigated the performance of competing circular error probable (CEP) estimators for small samples. This estimation is important in ICBM analysis because, due to expense, there are a limited number of ICBM test launches. In the most recent previous study (1993), Tongue considered five CEP estimators in a simulation test, attempting to determine the behavior of these estimators for populations of various bias, ellipticity, correlation, and sample size. In this paper, we build on Tongue's findings in three ways: (1) The number of estimators compared is expanded to eight. (2) Different factors and factor levels are used. (3) …

Analyzing And Improving Stochastic Network Security: A Multicriteria Prescriptive Risk Analysis Model, David L. Lyle

Theses and Dissertations

This research optimized two measures of network security by hardening components and improving their reliability. A common measure of effectiveness (MOE) for networks is statistical reliability, which ignores the effects of hostile actions. A new MOE which includes hostile actions was developed. Both measures require component reliability functions, derived using fault trees. Fuzzy Logic and Monte Carlo simulation were used to quantify uncertainty. Results from the model are compared to traditional Risk Assessment results.

Electrochemical Studies Of Spinel Limn2O4 Rechargeable Lithium Battery, Li Feng, Yuqin Chang, Lie Wu, Hong Li, Yibin San, Tianhong Lu

Journal of Electrochemistry

The spinel Li intercalation compound LiMn₂O₄ was prepared and studied using ac impedance and cyclic voltammogram techniques. It was first discussed that the impedance behaviors of LiMn₂O₄ electrode varied as lithium ion was intercalated in or out the electrode with the help of fractal theory. The Li reversible behaviors in LiMn₂O₄ electrode were shown by the cyclic voltammogram results.

Studies On The Cathodic Current Efficiency In The Electrodeposition Ni-Psz Gradient Coating, Jun Li, Dianlong Wang, Li Chen, Xinguo Hu

Journal of Electrochemistry

The cathodic current efficiency and the electrochemical behavior in electrodeposition Ni-PSZ gradient coating were investigated by various electrochemical techniques and scanning electron microscope. The results showed that the Ni-PSZ composite coatings can accelerate evolution of hydrogen with the increase of PSZ content. The overpotential of nickel reduction will be increased and that of hydrogen reaction will be reduced in the presence of PSZ particles in electrolyte. The effect of PSZ particles on nickel electrodeposition was preferentially to catalyze the formation of H ads . These all contributed to the lower current efficiency.

Studies On An Iron Heteropolyacid Redox Flow Battery, Peiju Sun, Wansheng You, Zhorgyin Tan

Journal of Electrochemistry

This paper reports a new Fe-HP redox flow cell. The positive and negative electrodes active materials are phosphomolybdic acid and acidified ferrous sulphate solutions respectively. Two activated porous carbon felt electrodes where the electrochemical reactions take place, are separated by a selective cation exchange membrane. The both couples have a suitable electrochemical reversibility on carbon and graphite electrodes. The active materials of the cell have very high stability. Moreover the cell has no life cycle limiting.

Electrochemical Synthesis And Characterization Of Ba-Pb-O And Bi-Pb-O Oxides, Min Xie, Liangzhong Zhao, Cuiying Xu, Jinbiao Zhang

Journal of Electrochemistry

Pb-based oxides Ba-Pb-O and Bi-Pb-O were synthesized from aqueous solutions by using electrochemical method. The resulting Ba-Pb-O and Bi-Pb-O were characterized using XPS, EDX and XRD. The results show that perovskite BaPb_0.9O₃ can be electrodeposited on the anode only from strong alkaline solution. In acid aqueous solution, conducting BiPb₂O_z oxide is fromed on the anode. In these oxides the nominal valence of lead is +4.

Problems Of The Study Of Anodic Films On Pb In Sulfuric Acid Solution (Ⅲ), Houtian Liu, Qunzhou Wang, Weifang Zhou, Wenbin Cai

Journal of Electrochemistry

The interstitial liquid among the particles in anodic Pb(Ⅱ) films could be the major passage for ion transportation. This is discussed with the mechanism of the cathodic reduction of anodic PbSO₄ film and the effect of Sb on the growth of anodic Pb(Ⅱ) oxides film.

Electrochemical Behaviors Of Isoalloxazine Confined In Montomorillonite Olay Modified Electrode, Zhibin Wu, Yuan Lin, Daodao Zhang, Haoqin Wu

Journal of Electrochemistry

A cyclic voltametric investigation of stability and redox properties of isoalloxazne on cetytrimethyammonium bromide (CTAB) modified montomorillonite clay platinium electrode in aqueous solution has been performed. pH dependent film concentrations and apparent diffusion coefficents were measured. The mechanism of the charge transport process with in the clay film were discussed.