Open Access. Powered by Scholars. Published by Universities.®

Engineering Science and Materials Commons™

Open Access. Powered by Scholars. Published by Universities.®

2003

Discipline
Institution
Keyword
Publication
Publication Type

Articles 31 - 60 of 95

Full-Text Articles in Engineering Science and Materials

Discussion On Factors Of Unstable 304 Stainless Steel Stress Corrosion Cracking, Xin-Sheng Zhang, Chun-Chun Xu, Gang Hu Aug 2003

Discussion On Factors Of Unstable 304 Stainless Steel Stress Corrosion Cracking, Xin-Sheng Zhang, Chun-Chun Xu, Gang Hu

Journal of Electrochemistry

The 304 stainless steels were stretched at low temperatures to get different martensite phase transformation.Ferrmagnetometer was used to measure the martensite phase content. It was found that the dislocation density of 304 stainless sted was increased unavoidably with increase of deformation.Transmission electron microscope (TEM) was used to study the distribution of the dislocation.The influence of microstructure change on SCC of 304 stainless steel was discussed by slow strain rate testing (SSRT) in 42% MgCl 2 boiling solution,metallurgical microscope and scanning electron microscope (SEM).The results showed that martensite phase and dislocation flaw act together on the SCC susceptibility of 304 stainless …

Go to article

The Electroless Plating Ni-Fe-P Alloy And Its Voltammetric Behavior, Sen-Lin Wang, Hui-Huang Wu Aug 2003

The Electroless Plating Ni-Fe-P Alloy And Its Voltammetric Behavior, Sen-Lin Wang, Hui-Huang Wu

Journal of Electrochemistry

Electroless Ni_Fe_P alloy deposition from an alkaline bath, containing sodium hypophosphite as reducer, boric acid as buffer agent and sodium citrate as complexing agent, was investigated. To increase the plating rate and to inprove the bath stability, the deposition parameters were optimized. The effects of process parameters (pH,temperature and mole ratio of [Fe 2+ ]/([Ni 2+ ]+[Fe 2+ ]) on the plating rate and deposit composition were examined and it was found that the presence of ferrous sulfate in the bath has an inhibitory effect on the alloy deposition. As a consequence, the per_centage of iron in the electroless Ni_Fe_P …

Go to article

The Mechanism Of Electrocatalytic Reduction Of Oxygen On Manganese Dioxide, Yu-Liang Cao, Han-Xi Yang, Xin-Ping Ai, Li-Fen Xiao Aug 2003

The Mechanism Of Electrocatalytic Reduction Of Oxygen On Manganese Dioxide, Yu-Liang Cao, Han-Xi Yang, Xin-Ping Ai, Li-Fen Xiao

Journal of Electrochemistry

The oxygen electroreduction on the MnO 2 electrode was investigated by analysis of the polarzation properties of oxygen reduciton and its dependence on MnO 2 discharge state,in combination with the characterization of discharge intermediate and the kinetic parameters of the oxygen reduction.Based on the experimental observation and mechanistic analysis,it was suggested that the reduction of oxygen was closely related to the discharge behaviors of MnO 2 .When MnO 2 was electrochimically reduced to MnOOH,it was immediately oxidized by oxygen molecules. Thus the oxygen reduction proceeds through continuous oxidation of the discharge product of MnO 2 and the MnO 2 catalyst …

Go to article

The Development And Verification Of Three Matlab Analysis Applications Programmed Specifically For Engage Team Projects., Jonathan W. Huber Aug 2003

The Development And Verification Of Three Matlab Analysis Applications Programmed Specifically For Engage Team Projects., Jonathan W. Huber

Masters Theses

This thesis outlines the development of three analysis applications for use in the freshmen Engineering Fundamentals Program (engage) at the University of Tennessee. Engage teaches freshmen engineering mechanics concepts through a set of integrated components including Lecture, Analysis and Skills, Problem Session, Physical Homework, and Team Projects. Presently, the students have limited access to any software analysis tools to aid the design process. The students have little experience writing the types of complex programs needed to analyze a particular project. Even more, they do not have the time. The applications provide a means for the students to perform an accurate …

Go to article

A Study On The Prediction Of Viscosity With The Use Of Numerical Simulation Software, Brian Robinson Aug 2003

A Study On The Prediction Of Viscosity With The Use Of Numerical Simulation Software, Brian Robinson

Masters Theses

A study was undertaken to numerically simulate the flow of highly viscous fluid. Simulating a highly viscous flow within a parallel plate plastometer will hopefully begin to bridge the gaps in the current knowledge of these viscous models. The modeling of this flow was performed using the canned code FiDAP from Fluent Inc. The results are compared with the analytical results calculated by NASA Marshall researchers.

Go to article

Study Of Geometric Effects On Local Corrosion Rates For Lbe Loop, Chao Wu Jul 2003

Study Of Geometric Effects On Local Corrosion Rates For Lbe Loop, Chao Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Corrosion is an extremely important issue in nuclear cooling system applications. Many scientific and engineering efforts have been contributed to the research of finding an ideal material, which has resistance to corrosive Lead Bismuth Eutectic (LBE). A Delta Loop was designed and constructed in Los Alamos National Lab (LANL) to obtain the experimental data. This loop is a multi-section closed system that differs in diameter from one part to another. As a result, an intensive study on the geometry effect is hence necessary and valuable. In this thesis, this problem was simulated by commercial software STAR-CD. Results provide a good …

Go to article

Optically Transparent, Scratch-Resistant, Diamond-Like Carbon Coatings, Xiao-Ming He, Deok-Hyung Lee, Michael A. Nastasi, Kevin C. Walter, Michel G. Tuszewski Jun 2003

Optically Transparent, Scratch-Resistant, Diamond-Like Carbon Coatings, Xiao-Ming He, Deok-Hyung Lee, Michael A. Nastasi, Kevin C. Walter, Michel G. Tuszewski

Department of Mechanical and Materials Engineering: Faculty Publications

A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleble to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit abherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced …

Go to article

Method For Producing Fluorinated Damond-Like Carbon Films, Marko J. Hakovirta, Michael Nastasi, Deok-Hyung Lee, Xiao-Ming He Jun 2003

Method For Producing Fluorinated Damond-Like Carbon Films, Marko J. Hakovirta, Michael Nastasi, Deok-Hyung Lee, Xiao-Ming He

Department of Mechanical and Materials Engineering: Faculty Publications

Fluorinated, diamond-like carbon (F-DLC) films are produced by a pulsed, glow-discharge plasma immersion ion processing procedure. The pulsed, glow-discharge plasma was generated at a pressure of 1 Pa from an acetylene (CH) and hexafluoroethane (CF) gas mixture, and the fluorinated, diamond-like carbon films were deposited on silicon <100>Substrates. The film hardness and wear resistance were found to be strongly dependent on the fluorine content incorporated into the coatings. The hardness of the F-DLC films was found to decrease considerably when the fluorine content in the coatings reached about 20%. The contact angle of water on the F-DLC coatings was found …

Go to article

Utilization Of Municipal Solid Waste Rejects In The Production Of A Recycled Plastic Waste Composite Material, Mohamed Kamal Abou Khatwa Jun 2003

Utilization Of Municipal Solid Waste Rejects In The Production Of A Recycled Plastic Waste Composite Material, Mohamed Kamal Abou Khatwa

Archived Theses and Dissertations

The solid waste disposal problem has grown significantly in the last decades imposing a lot of pressure on disposal and treatment acts. In the past, incineration and landfilling were the common methods for disposing of products of municipal solid waste. With the increasing volumes of waste generation and the legislative restrictions of these treatment methods, reuse of bulk waste is foreseen as the best alternative to disposal. Due to the current widespread use of plastic products in daily life, post consumer plastics now contribute significantly to municipal solid waste generation rates with a contradicting low participation in waste minimization practices. …

Go to article

Quelques Conseils À Nos Nouveau Diplomés, Fathi Habashi Jun 2003

Quelques Conseils À Nos Nouveau Diplomés, Fathi Habashi

Fathi Habashi

An advice, the old wise man Polonius offered to the young Hamlet was “Neither a borrower, nor a lender be”, may be no longer pertinent. Some more relevant advices are offered to new graduates of the twentieth century. Available in English, French, and Spanish

Go to article

Recent Progress In The Research On Electrodeposition Of Composite Coatings, Xiao-Bing Liu, Xu-Cheng Wang, Yu Chen, Dan-Hong Cheng, Zu-Zhan Yu May 2003

Recent Progress In The Research On Electrodeposition Of Composite Coatings, Xiao-Bing Liu, Xu-Cheng Wang, Yu Chen, Dan-Hong Cheng, Zu-Zhan Yu

Journal of Electrochemistry

Recent progress in the research on composite coatings prepared by electroplating technology is reviewed. The nanoscaled particles, electrocatalytic, photoactive composite coatings are emphatically discussed. The composite coatings prepared by dispersing nanoscaled particles could attain better hardness, wear resistance and corrosion resistance than those of composite coatings which prepared by adding micronscaled particles. As compared with pure metal electrode and alloy electrode, some electrocatalytic composite coatings electrode could markedly reduce the overvoltages of cathodic and anodic electrode reaction. In recent years, the electrocatalytic composite coatings which based on metal oxides and conductive polymer as matrix materials become a newest field of …

Go to article

Electrochemical Monitoring On The Deactivation Of A Metallic Oxide Anode, Li-Kun Xu, Shi-Zhe Song, Ting-Yong Wang, Guang-Zhang Chen May 2003

Electrochemical Monitoring On The Deactivation Of A Metallic Oxide Anode, Li-Kun Xu, Shi-Zhe Song, Ting-Yong Wang, Guang-Zhang Chen

Journal of Electrochemistry

The process of accelerated life test of an IrO2/Ta2O5 coated titanium anode was monitored using cyclic voltammetry and electrochemical impedance spectroscopy.The vatiation with electrolysis time of anodic voltammetric charge Q*,the double layer capacitance Cdl,the oxide film resistance Rf and the charge transfer resistance Rct for oxygen evolution was measured.A deactivation mechanism was proposed based on the observation results.

Go to article

Synthesis And Electrochemical Characteristics Of Nickel-Based Complex Oxide Li_Ani_(0.78)Co_(0.2)Cd_(0.02)O_2, Rong-Zhong Yuan, Mei-Zhen Qu, Zuo-Long Yu May 2003

Synthesis And Electrochemical Characteristics Of Nickel-Based Complex Oxide Li_Ani_(0.78)Co_(0.2)Cd_(0.02)O_2, Rong-Zhong Yuan, Mei-Zhen Qu, Zuo-Long Yu

Journal of Electrochemistry

The nickel_based complex oxide LiaNi0.78Co0.02O2 cathode materials for lithium_ion rechargeable batteries was synthesized by the improved solid_state reaction method with LiOH·H2O, ball_like Cd_doped Ni(OH)2 and Co2O3 as raw materials. The analysis ICP_AES proved that the as_prepared compounds were near the stoichiometric form. The XRD, SEM and electrochemical characteristics testing were also carried out. The results showed that the complex cathode material LiaNi0.78Co0.2Cd0.02O2 has layered structure, homogeneous surface distributions,uniform particles with good crystal morphology as well as stable electrochemical performances. At ambient temperature the resulted materials have a high reversible capacity and good cycling stability.Its highest initial reversible capacity is more …

Go to article

Perfluorinated Sulfonic Acid Lithium Conductivity Humidity Sensor, Hong-Feng Xu, Jing Liu, Li Wan May 2003

Perfluorinated Sulfonic Acid Lithium Conductivity Humidity Sensor, Hong-Feng Xu, Jing Liu, Li Wan

Journal of Electrochemistry

Treat carbon paper with 3% PTFE solution and dried in 340 ℃ for 40 minutes to enhance its intension, and level off the surface of the carbon paper with a mixture of XC_72 carbon black and PTFE solution. With those treated carbon paper as electrodes,recast Nafion thin film from 5% Nafion solution as humidity sensitive material, a solid polymer electrolyte humidity sensor was prepared on a thin PET film.Take the relative humidity data from several saturated salt solutions, the relationship between conductivity response and relative humidity was studied at different relative humidies.The results showed: when the polymer electrolyte was H+ …

Go to article

Study Of Marine Biocorrosion Using Afm And Molecular Techniques, Herbert H.P.Fang, Lichong Xu, Tong Zhang May 2003

Study Of Marine Biocorrosion Using Afm And Molecular Techniques, Herbert H.P.Fang, Lichong Xu, Tong Zhang

Journal of Electrochemistry

Biofilm is ubiquitous in nature.However,corrosin caused by biofilm is still by and large overlooked.This presentation is to demonstrate the applications of several newly developed analytical techniques in chemisrty and microbiology for the study of marine biocorrosion on steel.AFM(atomic force microscopy) was applied to investigate the initial formation mechanism of biofilm and the degree of corrosion of steel in polluted seawater.DNA/RNA_related molecular techniques were used to analyze the microbial composition corrosive biofilm. Results showed that microbial corrosion began within six days, and the corroded volume in the increased as a power function of time with an index 2.83. Most of the …

Go to article

Effect Of Scn~- On The Transition Current Of Zn During The Electrodeposition Zn-Co Alloys, Ren-He Yin, Wei-Min Cao, Zheng-Hua Fang May 2003

Effect Of Scn~- On The Transition Current Of Zn During The Electrodeposition Zn-Co Alloys, Ren-He Yin, Wei-Min Cao, Zheng-Hua Fang

Journal of Electrochemistry

For co_deposition of Zn_Co alloys at sufphate baths with micro_concentration of SCN- the transition current of Zn was found with the deposition process changing from normal Co_deposition to anomalous co_deposition, and the value of transition current increased with increasing SCN- concentration, but decreased with increasing value of pH. The existence of SCN- decreases the evolution overpotential of Co metal, but has no effects on the evolution overpotential of Zn metal and H2.

Go to article

Corrosion Behavior Of Reinforcing Steel In Concrete Subjected To Chloride Contamination By Eis, Rong-Gang Hu, Rong-Gui Du, Chang-Jian Lin May 2003

Corrosion Behavior Of Reinforcing Steel In Concrete Subjected To Chloride Contamination By Eis, Rong-Gang Hu, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Electrochemical impedance spectroscopy(EIS) was employed to study the influence of chloride on the corrosion behavior of reinforcing steel in concrete.In Nyquist plot,the spectrum consists of two semicircles,indicating that the reinforced concrete system contained two time constants,one derived from electrical double layer of reinforcing steel and the other from the deposition film of concrete layer.The depressed semicircle in lower frequency featured the non_faradic behavior of the electrical double layer (EDL) deviated from idea capacitor due to diffusive effect which was attributed to the surface roughness of rebar and the inhomogenity of concrete layer.Then the EDL was denoted by a constant phase …

Go to article

Selective Corrosion In Duplex Stainless Steel, Wen-Ta Tsai, Kuen-Ming Tsai, Chang-Jian Lin, Yan Fu May 2003

Selective Corrosion In Duplex Stainless Steel, Wen-Ta Tsai, Kuen-Ming Tsai, Chang-Jian Lin, Yan Fu

Journal of Electrochemistry

In duplex stainless steel, the two constituent phases, namely ferritic (α)and austenitic(γ) phases, have different crystal structure and chemical composition. They may thus exhibit different corrosion resistances in aqueous environment. In this investigation, an electrochemical technique with spatial resolution was employed to measure the potential difference between these two constituent phases in 2205 duplex stainless steel. Image analyzing techniques were also used to examine the preferential corrosion between α and γ phases. The experimental results showed that ferrite had a higher potential than austenite in0.01 mol/L NaCl solution. In 2 mol/L H2SO4+x mol/L HCl solution, two distinct peaks appeared in …

Go to article

The Electrochemical Behaviors Of A Novel Ferrocene Alkylthiol Sams On Au Electrode, Xiao-Gang Zhang, Yan-Li Shi, Hu-Lin Li May 2003

The Electrochemical Behaviors Of A Novel Ferrocene Alkylthiol Sams On Au Electrode, Xiao-Gang Zhang, Yan-Li Shi, Hu-Lin Li

Journal of Electrochemistry

A novel alkylthiol molecule containing ferrocene and pyridium moieties and its hydrogenated products were synthesized and subsequently assembled on Au electrode as SAMs. Cyclic voltammogram(CV) was used to investigate the structure_dependent electrochemical response of the SAMs in 0.1 mol/L HClO4 aqueous solution.

Go to article

Initial Stages Of Pd Deposition Onto Au(111) Electrodes From Pdso_4 Solution, Jing Tang, Petri M., Kibler L.A., Kolb D.M. May 2003

Initial Stages Of Pd Deposition Onto Au(111) Electrodes From Pdso_4 Solution, Jing Tang, Petri M., Kibler L.A., Kolb D.M.

Journal of Electrochemistry

Metal thin films have attracted considerable interest in relation to catalysis, energy, material, corrosion and environmental protection. Pd thin film is capable of proton reduction and strong hydrogen absorption, which has shown electrocatalytic activity to the oxidation of small organic molecules. In this paper, in_situ STM measurements are performed to study the deposition process and the influence of the surface structure and anion adsorption. When Pd is deposited from PdSO4 solution on Au(111) in the UPD range, a monolayer of Pd with pseudomorphic (1×1) structure was formed on the substrate with induced (3×7) R19° SO2-4 adsorption. With decreasing potential the …

Go to article

Preparation And Electrochemical Preformance Of Zn-La Alloys, Xian-Ling Meng, Hua-Bin Yang, En-Dong Yang, Xiao-Dan Wang, Hai-Chang Zhang, Jun-Hong Wang, Zuo-Xiang Zhou May 2003

Preparation And Electrochemical Preformance Of Zn-La Alloys, Xian-Ling Meng, Hua-Bin Yang, En-Dong Yang, Xiao-Dan Wang, Hai-Chang Zhang, Jun-Hong Wang, Zuo-Xiang Zhou

Journal of Electrochemistry

Zn_La alloys were prepared by solid phase diffusion method and the effects of La on the electrochemical performance of zinc electrodes were investigated using potentiostatic polarization technique and charging/discharging cycle test. The results showed that adding La to zinc electrode remarkably suppressed the zinc dendrite, the shape of zinc electrode and zinc corrosion, and hence, markedly improved the cycle performance of zinc electrodes. The discharging capacity of the zinc electrode containing 0.5at.% La which was the optimum was still 520 mAh/g after it cycled 80s at the current of 100 mA. The XPS showed that La element mainly adhered on …

Go to article

Oxidation Behavior Of Zr-Cu-Al-Ni Amorphous Alloys In Air At 300～500 ℃, H. Hsieh H., Kai W., G. Neih T., Kawamura Y. May 2003

Oxidation Behavior Of Zr-Cu-Al-Ni Amorphous Alloys In Air At 300～500 ℃, H. Hsieh H., Kai W., G. Neih T., Kawamura Y.

Journal of Electrochemistry

The oxidation behavior of the Zr_based bulk amorphous alloy (BMG; Zr_30Cu_10Al_5Ni in at.%) was studied in dry air over the temperature range 300～500 ℃. The kinetic results indicated that the amorphous alloy oxidized linearly at 300 ℃,while the parabolic oxidation was observed at 350～425 ℃, and the oxidation behavior at 500 ℃ was irregular and complicated. In general, the scales formed on the surface of the amorphous alloy were temperature_dependent, consisting of tetragonal_ZrO2 at 300　℃, and of mostly tetragonal_ZrO2 as well as minor amounts of monoclinic_ZrO2 and CuO at T≥350　℃.

Go to article

Corrosion Behavior Of Mg_(1.85)Mm_(0.15)Ni Hydrogen Storage Alloy Modified By Electroless Cu In Ch_3oh·H_2o Solutions, Hua-Bin Yang, Hai-Chang Zhang, Hua Sun, Xiao-Dan Wang, Zuo-Xiang Zhou May 2003

Corrosion Behavior Of Mg_(1.85)Mm_(0.15)Ni Hydrogen Storage Alloy Modified By Electroless Cu In Ch_3oh·H_2o Solutions, Hua-Bin Yang, Hai-Chang Zhang, Hua Sun, Xiao-Dan Wang, Zuo-Xiang Zhou

Journal of Electrochemistry

The corrosion behavior of the Mg1.85Mm0.15Ni (Mm:Ce_rich mischmetal) alloy modified by electroless Cu coating in different CH3OH_H2O solutions has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. These results showed that the corrosion behavior was improved after electroless Cu. The potentiodynamic polarization and electrochemical impedance spectroscopy results showed that the alloy electrode had more promising anti_corrosion behavior after coated in a 40%CH3OH_H2O solution. The values of corrosion current density and electrode reaction resistance were 5.6 mA·cm-2(11.7 mA·cm-2 for uncoated alloy electrode) and 22.25 Ω·cm2 (1.99 Ω·cm2 for the uncoated alloy electrode), respectively.

Go to article

A Bilayer Self-Assembled Membrane Electrode For Fluorescence And Its Electrochemical Characterization, Xiang-Ying Sun, Bin Liu, Yun-Bao Jiang May 2003

A Bilayer Self-Assembled Membrane Electrode For Fluorescence And Its Electrochemical Characterization, Xiang-Ying Sun, Bin Liu, Yun-Bao Jiang

Journal of Electrochemistry

The bilayer membrane was assemblied on Au electrode by the electrostatic interaction between the fluorescence regent 1_naphthylamine diacetate acid(NADA) and DL_Cysteine. The SAMs electrode NADA/Cys/Au can be used as fluorescence and electrochemical sensor for metal ions. This paper states the electrochemical characterization of NADA/Cys/Au and SAMs' application in continous determination for Cu2+ and Ni2+.

Go to article

Conductance Properties For Electrolyte Of Lithium Ion Battery At Low Temperature, Jing-Li Han, Yan-Mei Yu, Jian Chen, Chun-Tong Wang May 2003

Conductance Properties For Electrolyte Of Lithium Ion Battery At Low Temperature, Jing-Li Han, Yan-Mei Yu, Jian Chen, Chun-Tong Wang

Journal of Electrochemistry

The system of LiPF6_ethylene carbonate (EC) _methy1 acetate (MA) was studied. The conductivities of this system were measured under various composition and various salt concentrations at temperature range of 20～-50 ℃. The optimum composition of this system was selected. The tests of cyclic voltammography and charge_discharge were carried out. This system was compared with commercial electrolyte solution.

Go to article

Corrosion Prediction Of Carbon Steel In Concentrated Lithium Bromide Solutions At High Temperature Using Bp Neural Network, Nai-Bao Huang, Cheng-Hao Liang May 2003

Corrosion Prediction Of Carbon Steel In Concentrated Lithium Bromide Solutions At High Temperature Using Bp Neural Network, Nai-Bao Huang, Cheng-Hao Liang

Journal of Electrochemistry

Neutral network model has been developed for the computation of corrosion rate of carbon steel in LiBr solutions.The results indicate that the model is capable of reproducing the effects of changes in alkalinity,temperatures,LiBr and Na2MoO4 concentrations on the rates of general corrsion and good agreement between calculated and experimental corrosion rate is obtained.The model can be used to satisfactorily predict the corrosion rate of carbon steel in different concentrations of LiBr solutions containing different inhibitors at different temperatures.It also provides a novel method for corrosion monitoring of metals used in LiBr absorption chiller.

Go to article

Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann May 2003

Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann

Electrical & Computer Engineering Faculty Publications

The evolution of the band structure of β-In2 S3−3x O3x (BISO) thin films grown by physical vapor deposition, with composition x, is investigated using x-ray photoelectron spectroscopy. It is shown that the energy difference between the valence-band level and the Fermi level remains nearly constant as the optical band gap of the films increases. As a consequence, the difference between the conduction band level and the Fermi level increases as much as the optical band gap of the films. The calculation of the electronic affinity [ ] of the BISO thin films shows that it decreases linearly from 4.65 …

Go to article

A Study Of The Electron Beam Scattering Under Various Gaseous Environment, Jing He May 2003

A Study Of The Electron Beam Scattering Under Various Gaseous Environment, Jing He

Masters Theses

There are three objectives in this work: to experimentally measure the profiles of electron beams scattered by interaction with a gas, to measure total scattering cross-sections for gases and to apply the cross-section data in a suitable Monte Carlo simulation to predict beam scattering profiles for comparison with experiment.
The experimentally measured profiles cover a wide range of intensity variation. There are two evidenced regions: an inner region and an outer skirt corresponding to inelastic (small angle) and elastic scattering respectively are appeared. These profiles use the planar p-n junction gives us an overall look at the electron beam spreading, …

Go to article

Fuzzy System Identification Based Upon A Novel Approach To Nonlinear Optimization, Raymond Scott Starsman Apr 2003

Fuzzy System Identification Based Upon A Novel Approach To Nonlinear Optimization, Raymond Scott Starsman

Electrical & Computer Engineering Theses & Dissertations

Fuzzy systems are often used to model the behavior of nonlinear dynamical systems in process control industries because the model is linguistic in nature, uses a natural-language rule set, and because they can be included in control laws that meet the design goals. However, because the rigorous study of fuzzy logic is relatively recent, there is a shortage of well-defined and understood mechanisms for the design of a fuzzy system. One of the greatest challenges in fuzzy modeling is to determine a suitable structure, parameters, and rules that minimize an appropriately chosen error between the fuzzy system, a mathematical model, …

Go to article

Experimental And Computational Failure Analysis Of Graphite/Bismaleimide Laminated Composite And Carbon Foam In Sandwich Construction, Troy C. Welker Mar 2003

Experimental And Computational Failure Analysis Of Graphite/Bismaleimide Laminated Composite And Carbon Foam In Sandwich Construction, Troy C. Welker

Theses and Dissertations

Sandwich beams consisting of a carbon foam core and graphite/bismaleimide face sheets were constructed and tested. Nine specimens were fabricated using three distinct cross-ply symmetric face sheet layups with a constant core thickness. Four-point bend testing controlled by a constant rate of midspan vertical displacement was used to load the specimens to failure. Displacements and strains from the experiment were compared to analytical sandwich beam theory and displacements and failure loads were compared to a layerwise finite element solution. A phenomenological failure criterion was developed that compares favorably with experimental failure data. The finite element solution gives failure within an …

Go to article

First Prev Next Last