Engineering Commons^™

Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon

Electrical and Computer Engineering Faculty Publications

This guest editorial provides an overview of the topical area and an introduction to the articles featured in the special section.

Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao

Electrical and Computer Engineering Faculty Publications

It is commonly known that the spatial profiles of the diffracted light beams during Bragg acousto-optic interaction are distorted due to the Bragg angle selection mechanism. All the conventional studies on this effect use the paraxial approximation. But this approximation should be amended when the incident angle of the light is large enough that the diffracted light waves do not propagate closely along the optic axis of the acousto-optic diffraction system. By using a spatial Fourier transform approach, we rigorously study the light beam profile deformation effect of the diffracted light during the Bragg acousto-optic interaction beyond the paraxial approximation. …

Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan

Electrical and Computer Engineering Faculty Publications

A transfer function formalism developed earlier for the propagation of profiled optical beams through acousto-optic Bragg cells is revisited and applied to a thick holographic grating. The results based on the holographic coupled wave model and the acousto-optic multiple scattering model are shown to be compatible, and equivalent parameters such as the Q and grating strength are defined for the two systems. Results for a Gaussian spatial profile are numerically computed and compared. For the holographic grating, a profiled beam may be interpreted as an angular misalignment or Bragg-angle mismatch problem. The case of Bragg-wavelength mismatch is also investigated for …

Newton Parameter Update Algorithm For Recurrent Neural Networks Applied To Adaptive System Identification And Control, Donald Allen Gates

Electrical & Computer Engineering Theses & Dissertations

This paper shows that the combination of a second-order neural network parameter update algorithm and internal network feedback can be effectively used for adaptive, nonlinear, dynamical system identification and control. Adaptive neural identification and control algorithms are typically utilized for real-time applications where the rate of adaptation is often critical. A fast, adaptive network parameter update algorithm is presented.

Simulation results show that this algorithm is capable of quickly identifying and adapting to changes in system parameters, making it feasible to use for real-time control and fault accommodation applications.

Dynamic And Interactive 3d Simulation Over The World Wide Web, Rajesh Vennam

Electrical & Computer Engineering Theses & Dissertations

The thesis presents the development of a new and novel three-dimensional simulation tool over the WWW using Virtual Reality Modeling Language (VRML). VRML is a 3D analog to HTML and serves as a simple, multiplatform language for publishing 3D Web pages. In general, most people use VRML for developing three-dimensional models or worlds that provide little or no interaction for the users. This tool combines interaction and dynamic object creation. A thorough study of VRML is done to explore the features of VRML that could be combined to develop methodologies for creation of dynamic and interactive 3D objects over the …

Differential Reflection Phase Shift Under Conditions Of Attenuated Internal Reflection, R. M.A. Azzam

Electrical Engineering Faculty Publications

The angle-of-incidence dependence of the differential reflection phase shift Δ between p and s polarizations is considered a function of the real and imaginary parts of the relative complex dielectric function ε of an interface in the domain of fractional optical constants, i.e., under conditions of internal reflection. The constraint on complex ε such that oscillatory and monotonic angular responses are obtained is determined. A sensitive and stable technique, which is based on attenuated internal reflection ellipsometry between the Brewster angle and the critical angle, is proposed for measuring small induced absorption (ε_i∼10⁻⁵) in the medium …

Development And Application Of Adaptive Dynamic Grids For Wake Vortex/Ground Interaction, Ilker Emin Türkgeldi

Mechanical & Aerospace Engineering Theses & Dissertations

An adaptive and dynamic grid approach is developed for the numerical computations of wake vortex flow problems with ground interaction. The unnecessary grid points at the far field of the original, large, single zone grid are removed for computational efficiency. Next, the grid is modified into an adaptive one, where the fine core region keeps track of the vortices and can be split into two regions when the vortex separation distance exceeds a specified limit length. In the final step a multi zonal feature is added to this grid by means of two embedded grids placed at the vortex centers …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 6, June 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Media Coverage Of Epa's Draft Dioxin Reassessment Report, Sharon M. Friedman, Megan A. Fitzpatrick, Brenda P. Egolf

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

Using content analysis, the authors examine the utility of news media in democratic decision making.

Parallel Digital Signal Processing On A Network Of Personal Computers Case Study: Space-Time Adaptive Processing, Fernando Silva

Theses and Dissertations

Network based parallel computing using personal computers is currently a popular choice for concurrent scientific computing. This work evaluates the capabilities and the performance of the AFIT Bimodal Cluster (ABC); a heterogeneous cluster of PCs connected by switched fast Ethernet and using MPICH 1.1 for interprocess communication for parallel digital signal processing using Space Time Adaptive Processing (STAP) as the case study. The MITRE RT_STAP Benchmark version 1.1 is ported and executed on the ABC, as well as on a cluster of six Sun SPARC workstations connected by a Myrinet network (the AFIT NOW), and on a IBM SP for …

A Study On The Cathode Protection Potential Against Pitting Corrosion, Chun-Chun Xu, You-Ping Liu, Xiao-Bo Zhang, Xu-Hui Zhao

Journal of Electrochemistry

The methods have been developed to determine the protection potential against pitting corrosion. They are based on the theory that the pitting protection potential (E_p) is actually the transition potential of the direction of current between the occluded cell and the external surface (E_T). E_T lasts from -220 mV to -440 mV (SCE), the lowest of which can be considered as cathode protection potential. The E_p values determined with cyclic potentiodynamic polarization method is included in the E_T with above methods.

The Behaviors Of Capacity Loss Of Limn2O4 Cathodeat Elevated Temperatures, Xiao-Hong Hu, Han-Xi Yang, Xin-Ping Ai, Sheng-Xian Li, Xin-Lin Hong

Journal of Electrochemistry

The capacity loss of spinel LiMn₂O₄ cathode at elevated temperatures was evaluated by constant current charge-discharge methods and it was found that serious capacity loss and cycleability decrease occured at above 50, especially for the charged cells. The mechanisms for this phenomena were examined by atomic emission and infrared spectrometry of the electrolyte, XRD measurment of the cycled elecrode and microelectrode voltammetry of LiMn₂O₄ at room and elevated temperatures. The results showed that with increasing temperature, Mn and Li ions tended to redistribute partly in the spinel framework due to the disproportion of Mn …

Oxidation And Adsorption Of Deoxyribonucleic Acid At Highly Ordered Pyrolytic Graphite And Glass Carbon Electrode, Jian-Zhang Zhou, Ling-Ling Wu, Jin Luo, Zhong-Hua Lin

Journal of Electrochemistry

It is shown that calf thymus DNA (CT DNA) can be adsorbed at highly ordered pyrolytic graphite (HOPG) electrode and detected by differential pulse voltammetry (DPV) and electrochemical atomic force microscopy (ECAFM). It is found that controlled potential pre-polarization influences largely the adsorption of dsDNA while it has little influence on ssDNA. It is demonstrated that ECAFM is useful to exploit adsorption of DNA at HOPGE. The pattern of adsorption of DNA at HOPG electrode that fits best with the experimental data is proposed. The results aslo shows that UV/Vis reflection spectroscopy, which has not been used in studying electrochemical …

The Adsorption Stability Of Interface Corrosion Inhibitor, Fu-Xing Gan, Di-Hua Wang, Jin-Yun Zou

Journal of Electrochemistry

Some new results on the adsorption stability of interface corrosion inhibitor are presented. The concept of adsorption stability and the factors influencing the adsorption stability were discussed. It is shown that the anodic desorption potential can be employed to evaluate the adsorption stability of the inhibitor as an empirical character in some conditions. Electrochemical oscillations phenomena were observed for the first time on a rotating iron electrode in H₂SO₄ solution containing organic inhibitor in the active potential region. These potentiostatic current oscillations can occur under cathodic polarization, as well as under anodic plarization. The oscillation period, amplitude, …

Electrochemical Behavior Of Riboflavin On Glassy Carbon Electrode, Hong Li, Lin-Cai Jiang, Liang-Nian Ji

Journal of Electrochemistry

The electrochemical behavior of riboflavin(RF) on glassy carbon has been investigated by using potential sweep, rotating ring-disc electrode and the measurement of differential capacitance. It is shown that a single well-behaved oxidation-reduction wave corresponding to a reversible two-electrons reaction apears in medium of pH<6, and the adsorption of RFH₂ formed by electro-reduction is weak and hence its solubility is good. In medium of pH>6, there are two separating but overlapping partly oxidation-reduction waves corresponding to two-step one-electron reaction. The adsorptions of RFH and RFH₂ produced by reduction reactions in medium of 6

Study On The Microband Array Electrode-Based Glucose Microsensor, Neng-Qin Jia, Chui-Jue Sun, Lin Gao, Zong-Rang Zhang, Jian-Zhong Zhu, Guo-Xiong Zhang

Journal of Electrochemistry

The microband array electrode (MAE) consisting of 11 Pt microband of 5 m in wide, 2000 m long and 85 m gap was fabricated with a thin film techology. The MAE was characterized by means of cyclic voltammetry in a solution of K₃Fe(CN)₆ and H₂O₂. The results showed higher current density on MAE than on conventional Pt eletrode due to the strong edge effect of the former. A glucose microsensor was constructed with the substrate electrode of microband array. Microband array electrode was modified by Nafion followed by the immobilization of ferrocene onto …

In Situ Ftir Spectroelectrochemical Study Of Palladium Hexacyanoferrate Thin Film Deposited On Glassy Carbon Electrode, Ai-Li Bo, Xiang-Qin Lin

Journal of Electrochemistry

The electrochemically deposited Palladium hexacyanoferrate thin film on Glassy Carbon electrode (PdHCF|GC) has been studied in HCl, KCl and NaCl solutions by in-situ external reflection FTIR spectroelectrochemical technique. It is found that the behavior of the electroactive PdHCF film can be understood in terms of two states: Pd₂Fe(II)(CN)₆ formed in the inner layer and (M⁺)2Fe(II)(CN)₆ (M⁺: electrolyte cation) formed in the outer layer. The inner layer is oxidized at E_m=0.87 V in 1 mol/L KCl, while for the outer layer Em=0.77 V(vs. Ag/AgCl). In 1 mol/L NaCl or HCl solutions, …

Influence Of Ptfe And Nafion On The Utilization Efficiency Of Pt/C Catalyst In Pemfc, Xiao-Liang Cheng, Bao-Lian Yi, Jing-Xin Zhang, Ming Han, Ya-Guang Qiao

Journal of Electrochemistry

With cycling voltammetry curve(C-V), TEM and SEM photographs, the influence of PTFE and Nafion on the platinum utilization in catalyst layer of PEMFC was investigated. The results show that in gas diffusion electrode, the blocking effect of PTFE in the platinum utilization is not pronunced. In the thin-film catalyst layer, the electron conduct of the catalyst was blocked by the nafion solid and this caused the decrease of platinum utilization. With the increase of the nafion content in the catalyst layer, both platinum utilization and the electron conductivity decreased in the catalyst layer. Because the molecule size of nafion is …

Preparation And Application Of Gold-Film On The Surface Of Bacterial-Modified Carbon Paste Electrode, Rong-Zong Hu, Yan-Ping Ruan, Hao Xu, Jin-Kun Fu, Wei-De Zhang, Wen-Yun Hu

Journal of Electrochemistry

A novel method for preparation of gold-film composed of ultra-fine gold particles was reported in this paper. The gold-film was prepared by electrochemical method on the surface of the paste electrode modified with the strain Bacillus sp. D01 which has strong ability to absorb and reduce Au³⁺. In addition, this paper reported an experimental method of determining trace amount of Cu²⁺ in water solution using cathodic stripping analysis to estimate the performances of the obtained gold-film. The experimental results indicated that this new method for preparation of gold-film is simple. The obtained gold-film electrode is stable and …

The Influence Of Heat On The Measurement Of Photocurrent At The Anodic Film Of Nickel Electrode, Hang Chen, Zhi-Yu Jiang

Journal of Electrochemistry

The influence of heat on the measurement of photocurrent for nickel electrode in 1 mol/L NaOH solution was investigated by using the photocurrent, photothermal and thermal current methods. It was found that the appearance of photocurrent in potential region of -0.75~0.20 V (vs. Hg/HgO electrode) was due to the p-type semiconductor properties of Ni(OH)₂ film in which is agree with the previous report. In the Ni(OH)₂/NiOOH redox potential region, the increase of temperature at the surface of working electrode during irradiation significantly promoted the electrochemical reaction strongly. The photocurrent observed in potential region 0.20~0.57 V is mainly …

Effects Of Nickel Content And Simulated Heat Affected Zone Of 2205 Duplex Stainless Steel On Pitting Corrosion, Horng-Yih Liou, Ju-Tung Lee, Wen-Ta Tsai, Rong-Iuan Hsieh, Yeongtsuen Pan

Journal of Electrochemistry

The effects of nickel content and Gleeble simulated heat affected zone (HAZ) of 2205 stainless steel on pitting corrosion were investigated in this paper. The results showed that nickel content, ranging from 4.5 wt% to 6.5 wt% in base metal, had only a minor effect on the electrochemical polarization curves, with all E_np's and E_pp's falling in the rang of 1100~1200 mV. Comparing with the base metal, the simulated HAZ microstructure caused an increase in the anodic current density, a distinct decrease in both E_np and E_pp , and a reduction in the passive …

The Influential Factors On The Triboelectrochemical Behaviors Of The Passive Alloys, Dong-Bai Sun, Tao Li, Hong-Ying Yu, De-Jun Yang

Journal of Electrochemistry

The tribocorrosion process of Fe-Cr alloys with different Cr content in H₂SO₄ solution was investigated. The influence of applied load, friction velocity, Cr content and concentration of H₂SO₄ in solution on the triboelectrochemical behaviors of the alloys was analyzed. It is shown that applied load and friction velocity have singnificant influence on the tribocurrent density in passive region when friction process occurs on part of the surface of alloy. Increasing the corrosion resistance of alloys or decreasing the aggressive of the solution can reduce the alloy removal velocity.

Investigation Of Solution Chemistry In Crevice Of Carbon Steel And Its Anodic Polarization Behavior, Zhuo Chen, Cui-Wei Du, Bei Cao, Yin-Shun Wu, Hai Yang, Zheng-Rong Zhang

Journal of Electrochemistry

A self-made wedge-shaped simulated crevice apparatus was designed to investigate the solution chemistry in crevice of carbon steel and its anodic polarization behavior. For carbon steel with 3.5%(wt) NaCl, the change and the distribution of electrode potential, concentration of Cl^- and pH value of solution in the crevice, and the current density of metal in the crevice were measured respectively under various conditions of anodic polarization. The results showed that without polarization the metal about 2 cm away from the opening of the crevice was attacked preferentially because of its lowest free corrosion potential. The anodic polarization promoted the …

Zro2 And Zro2-Y2O3 Coatings Deposited By High Energy Pulse, Wei-Ping Yu, Ye-Dong He, Li-Na Zhang, De-Ren Wang

Journal of Electrochemistry

The basic rule and influence factors on deposition of ZrO₂ and ZrO₂-Y₂O₃ coatings by high energy pulse were studied. After the oxidizing experiment in air at 1 000 for 100 h, it was shown that the oxidation resistance of 18-8 stainless steel was marketly enhanced by depositing ZrO₂ and ZrO₂-Y₂O₃ coatings. The oxidation resistance was increased about 20 times and the oxide scale spallation resistance was increased about 100 times.

Study On The Hydrogen Permeation Through Zinc Electrodeposit, Jiang-Li Cao, Ji-Xun Wu, Yan-Ping Lu, Jie Shi

Journal of Electrochemistry

The electrochemical hydrogen-permeation technique was used to study hydrogen permeation through zinc electrodeposit with bilayer specimens of Fe substrate/zinc electrodeposit. The effect of coating thickness on hydrogen diffusion coefficient and hydrogen steady-state flux was studied. The results showed that hydrogen diffusion coefficient was approximately in the range of 10-11 cm²·s^-1 rank and zinc coating could retard hydrogen permeation. Accordingly, hydrogen steady-state flux and effective diffusion coefficient declined while the coating thickness increased.

Effect Of Inhibitor On Electrochemical Behavior Of 1cr18 Stainless Steel In Acidic Solution Under Friction, Jin-Ping Xiong

Journal of Electrochemistry

The electrochemical behavior of 1Cr18 stainless steel had been studied using a reciprocating triboelectrochemical equipment under friction in 0.2 mol/L H₂SO₄ solution with and without addition of thiourea, the frictionized surface of 1Cr18 stainless steel had been examined by the SEM, XPS and IR. The results showed that the loss rate of 1Cr18 stainless steel in the solution could be reduced by addition of thiourea. The adsorption of thiourea on the surface of 1Cr18 stainless steel prohibited the oxidization of Cr³⁺ to form Cr(Ⅵ) and formation of passive film consisting of CrO₄^2- or/and Cr(Ⅵ), …

Modeling The High-Speed Switching Of Far-Infrared Radiation By Photoionization In A Semiconductor, Thomas E. Wilson

Physics Faculty Research

Data from an earlier study [T. Vogel et al., Appl. Opt. 31, 329 (1992)] on the subnanosecond switching of 119-μm radiation in high-resistivity silicon by pulsed UV laser radiation, is compared with a refined one-dimensional numerical multilayer model accounting for the generation, recombination, and diffusion of the free carriers on the resulting far-infrared optical properties of the silicon. The inclusion of recent measurements for carrier-density and temperature-dependent transport parameters leads to improved agreement between experiment and theory.

Santa Clara Magazine, Volume 41 Number 1, May 1999, Santa Clara University

Santa Clara Magazine

8 - A BRIDGE BETWEEN WORLDS By President PaulL. Locatelli, S.J. 'Go. President Locatelli examines the value of service learning for students, the University, and America's social fabric.

12 - A GIANT ARTIST By Ann Granning Bennett. Auguste Rodin's sculptures are now on view at the de Saisset Museum. The question is: How do high-profile art shows like this one come about?

18 - ARIZONA'S DIPLOMATIC TOP COP By Tamara Straus. Janet Napolitano ' 79 , Arizona's newly elected attorney general , discusses the challenges of public office as well as politics, ethics, and fighting crime.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 5, May 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Two Approaches To Critical Path Scheduling For A Heterogeneous Environment, Guangxia Liu

Computer Science Theses & Dissertations

Advances in computing and networking technologies are making large scale distributed heterogeneous computing a reality. Multi-Disciplinary Optimization (MDO) is a class of applications that is being addressed under this paradigm. It consists of multiple heterogeneous modules interacting with each other to solve an overall design problem. An efficient implementation of such an application requires scheduling heterogeneous modules (with different computing and disk 1/0 requirements) on a heterogeneous set of resources (with different CPU, memory, disk IO specifications).

Given a set of tasks and a set of resources, an optimal schedule of the tasks on the resources is very hard to …