Physical Sciences and Mathematics Commons^™

College Of Engineering Senior Design Competition Fall 2005, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps to focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects …

Multiple Channel Laser Beam Combination And Phasing Using Stimulated Brillouin Scattering In Optical Fibers, Brent W. Grime

Theses and Dissertations

Brightness scaling lasers using stimulated Brillouin scattering (SBS) in optical fibers is explored. A multiple-channel amplifier approach is used to increase the total power of a laser system while avoiding a significant burden on a single channel. The work explores two approaches utilizing both SBS beam cleanup and SBS piston error conjugation. A unique beam combiner that takes advantage of the SBS beam cleanup properties of a long, gradient-index multimode fiber was designed and tested. The beam combiner was developed to combine multiple-channel laser beams simultaneously with high input and output coupling efficiency. The design for the SBS beam combiner …

A Continuous Operation For Electroreduction Of Oxalic Acid To Glyoxylic Acid, Xiao-Hui Hu, Xiang-Fei Yan, Yu-Zhong Su, Jun Li

Journal of Electrochemistry

A simulative-continuous-operation approach was proposed to study the continuous operation for electroreduction of oxalic acid to gloxylic acid using a packed bed reactor and a parallel reactor with cooled cathode in order to solve the low productivity problem in current state by using traditional reactor.The effects of the concentration of oxalic acid and temperature on this process were also studied.Results showed that,after 30min of the reaction(residence time),the mass fraction of the produced glyoxylic acid in the catholic solution could reach 3.76% and 3.66% with respect to a saturated oxalic acid method and a step-temperature decreasing method.From this study,we conclude that …

The Optimal Sulfonation Conditions Of Self-Doped Polyaniline Obtained By Using Experimental Strategies, Wen-Yar Li, Chi-Chang Hu

Journal of Electrochemistry

The optimal sulfonation condition of self-doped sulfonated polyaniline(prepared from leucoemeraldinebase;denoted as LEB-SPANI) with a high electronic conductivity was obtained by experimental strategies,includingthe fractional factorial design(FFD) and central composite design(CCD).From the FFD experiment,the self-doped LEB-SPANI prepared at a lowtemperature(4oC),a short reaction time(1 h),and a small volume of fumingsulfuric acid(10 mL) showed a better conductivity(ca.127 mS/cm).In the CCD study coupled with a confirmationtest,the highest conductivity(ca.141 mS/cm) of the LEB-SPANI film was obtained under a sulfonation temperatureof 4oC,a sulfonation time of75 minutes,and a volume of8 mLof30% fuming sulfuric acid.The textural cha-racter-istics of self-doped LEB-SPANI were characterized by Fourier transform infrared(FTIR) spectroscopy,four-pointprobe method,and X-ray …

Electrochemical Oxidation Of Organic Additives In Tin Plating Electrolytes, Yin-Mei Cheng, Lan-Kun Cai, Qiang Song

Journal of Electrochemistry

Cyclic voltammetry(CV) was used to characterize the voltammetric behaviours of organic additives,e.g.PSA(phenolsulfonic acid)、EN(ethoxylatedα-naphthol) and ENSA(ethoxylatedα-naphthol sulfonic acid),on the anode surface.In PSA solutions,an anodic peak was obtained and the peak potential was about 1.2V.In EN and ENSA solutions,two anodic peaks were obtained and the peak potentials were about(0.95V) and 1.3V.The products of galvanostatic electrolysis were separated by HPLC(high performance liquid chromatography) and analyzed by EI/MS(electron ionizing mass spectrometry).The mechnism of the electrochemical oxidation was also disussed.

Electrochemical Disinfection Method To Treat Wastewater From Hospitals, Lizhi-Fu Lizhi-Fu

Journal of Electrochemistry

Electrochemical disinfection method was used to treat wastewater from hospitals.The mechanism of electrochemical disinfection was researched by using the different anode materials.The results showed that when the titanium coated with noble metal(Ru、Pt、Ir)oxide was used as an anode and stainless steel as a cathode,the current density was 6 mA/cm~(2),hydraulic retention time was 15 min,air flow rate was 40 L/h,the rate of anode effective area to the inner water volume was 1.0,the amount of total colibacillus was below 500 CFU/L after electrochemical disinfection,All these meet the first order of Effluent Discharge Standard(GB8978-98).

Solid Oxide Fuel Cells-Materials And Prospects, Molenda Janina, Marzec Jacek

Journal of Electrochemistry

The paper summarizes and discusses the basic properties of solid oxide fuel cell(SOFC) components(electrode materials and electrolyte) from the point of view of their essential functional parameters suck as chemicalstability,transport,catalytic and thermomechanical properties under operational conditions in a SOFC.An interrela-tion between the defect structure of these materials related to oxygen nonstoichiometry and their electronic propertiesand catalytic activity was shown.Single-chamber fuel cell concept was also presented.

A Study Of Overcharge Characteristic Of Lithium-Ion Cells, Jing Pang, Shi-Gang Lu, Sha Liu

Journal of Electrochemistry

The overcharge characteristics and effect factors of lithium-ion cells containing LiMn_(2)O_(4)cathodes were studied in detail.Overcharge testing of Lithium-ion cells with a systematic variation in the cell balance demonstrated that the overcharge characteristics of Lithium-ion cells was affected by the amount of cathode in the cells,which is independent of the amount of anode material.The rate of charge was found to be an important parameter,as electrolyte complete decomposition at low charge rates caused the end of overcharge testing,while high charge rates accelerated the rate of heat generation in the cells and the cell temperature increased as a result of insufficient heat dissipation.The …

Silicides And Composites Materials As Anodes For Lithium Ion Batteries, Jun-Mei Yan

Journal of Electrochemistry

The anode materials of Mg_(2)Si and MnSi were synthesized by mechanically activated annealing(MAA) techniques in this work and the in electrochemical performances were also studied.A series of composite materials of Mg_(2)Si and CNTs or CMS were prepared by ball-milling method respectively.The reversible capacities of the composites were higher than that of the pure Mg_(2)Si and pure carbon materials.The cyclic performances have been improved greatly by ball-milling of the Mg_(2)Si and carbon materials.Results show that ball-milling method is one kind of method to make alloy materials into practical use.

The Mechanism Of Ethylenediamine On Electroless Ni-B Alloy Deposition, Sen-Lin Wang

Journal of Electrochemistry

The effects of ethylenediamine stabilizer on the deposition rate and on the stability of the plating bath for electroless deposition of Ni-B alloy were investigated.It was found that the addition of ethylenediamine greatly enhances the stability of the electroless plating bath.The electrochemical polarization including cathodic and anodic polarizations measurements were carried out to examine the effect of ethylenediamine on the deposition process.The results show that ethylenediamine affects both the cathodic and the anodic polarization processes.The oxidation current of the reducer and the reduction current of Ni-B alloy decrease greatly when ethylenediamine was added into the plating bath.The infrared spectroscopy(IR) experiments …

The High Temperature Corrosion Of 2205 Duplex Stainless Steel With Nacl Deposit, Fu-Fu Peng, Chaur-Jeng Wang, Yu-Chang Lin

Journal of Electrochemistry

The objective of this study was to figure out the hot corrosion behavior of 2205 duplex stainless steel(2205 DSS) within the temperature ranges from 550 to 850℃ in the static air condition with 2 mg/cm~(2)NaCl deposit,and in the air atmosphere condition with a constant flow rate of 500 vppm NaCl_((g)),respectively.Experimental results show that the hot corrosion kinetics met the parabolic rate law and the corrosion rate increased constantly with increasing temperature.The scales formed included Fe_(2)O_(3)/Fe_(3)O_(4)/Cr_(2)O_(3) and FeCr_(2)O_(4)from outer layer to inner layer.The sequence of formation is independent of the environment temperature,but the SiO_2 and NiO can be found in the …

A Study Of Three Corrosion Inhibitors For Reinforcing Steel In Sps Solution By Electrochemical Methods, Bing Zhao, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Some electrochemical techniques such as linear polarization,electrochemical noise and EIShave been employedto study the inhibition behavior of N-lauroyl sarcosinate,β-sodium glycerophosphate and D-sodium gluconate for the reinforcing steel immersed in simulated concrete pore solution(SPS) with NaCl addition.The results show that D-sodium gluconatehas an obvious inhibitive effect for the reinforcing steelin containingCl~(-)SPS solution.It has been proposed that the corrosion inhibition of D-sodium gluconate is due to its competitive adsorption and precipitation on steel surface in the simulated concrete environment.

Effect Of Hco_3~-Concentration On Co_2 Corrosion In Gas And Oil Fields, Guo-An Zhang

Journal of Electrochemistry

The effecs of HCO_3~-concentration on CO_(2) corrosion in gas and oil fields were investigated by carrying out potentiodynamic scans and weight loss tests.Potentiodynamic polarization curves showed that the cathodic current density decreased with cm increase of HCO_3~-concentration when [HCO_3~-] was lower than 0.042(mol/L.)The cathodic reations were promoted by increasing [HCO_3~-] when it reached 0.126 mol/L,(Anodic) behavior was an active process at low er [HCO_3~-] concentration and the anodic current density decreased with the increase of [HCO_3~-] concentration.An evident active-passive behavior exhibited in anodic process at 0.126 mol/L HCO_3~-.Under high pressure and high temperature,the corrosion rate of steel X65 decreased with …

An Electrochemical Study Of Electroless Copper Plating Using Glyoxylic Acid As Reducing Agent, Li-Qiong Wu, Fang-Zu Yang

Journal of Electrochemistry

The electroless copper plating using glyoxylic acid as a reducing agent,Na_(2)EDTA as a chelating agent and K_(4)Fe(CN)_(6) and 2,2'-dipyridyl as additives was studied.The effect of chelating agent and addtives on the polangation behaviovs of copper reduction and glyoxylie acid oxidation were analyzed by linear sweep voltammetry.The results mainly demonstrated that the chelating agent hindered both the oxidation of glyoxylic acid and the reduction of copper complexing ions.It has revealed that K_(4)Fe(CN)_(6)and 2,2'-dipyridyl(with the content over than 20 mg/L)both played negative actions on the oxidation of glyoxylic acid.

The Deactivation Mechanism Of Metal Oxide Anodes Under Alternative Current Electrolysis Condition, Jun-Tao Wang

Journal of Electrochemistry

The metal oxide anodes coated on titanium used in seawater electrolysis were prepared by thermal decomposition.Their morphologies、compositions and phase structures were determined by scanning electron microscope(SEM)、energy dispersive X-ray detector(EDX) and X-ray diffraction(XRD).The electrochemical properties of the anodes were characterized by accelerated life test,cyclic voltammetry and electrochemical impedance spectroscopy.SEM、EDX and XRD showed that solid solution structures of(Ru,Ir,Ti)O_(2)and(Ir,Ti)O_(2) were formed after pyrolysis,the solid solution structures and active components were disappeared after the deactivation of the anodes.Electrochemical results indicated that the active area decreased and the coating resistance increased,which are resulted by active component falling off from the anode surfaces.Hence,the deactivation of the …

Copper Electrodeposition Under The Perturbation Of Hard Particles, Zeng-Wei Zhu, Di Zhu

Journal of Electrochemistry

Copper electrodepositon was carried out on the rotating cathode,with hard particles(such as ceramic beads) filling between the electrodes.The rotation of cathode led hard particles to polish and impact the surface of deposit during electrodeposition.Copper deposits with a mass of cuspidal nodules were produced in acid sulfate solutions while brittle deposits without nodules were produced in alkaline sulfate solutions.It was also found that brightening and smoothing deposit could be obtained from the alkaline solution,and the deposit was approximatively disordered orientation with granular morphology of about 100~300 nm.The results show that the polishing and impact of hard particles can effectively disturb the …

Electrochemical Controllable Preparation Of Hydroxyapatite Coating With Different Morphologies And Preliminary In Vitro Tests, Hai-Yan Shi, Ren Hu, Chang-Jian Lin

Journal of Electrochemistry

The Controllable electrochemical deposition has been developed to prepare the hydroxyapatite(HA) coatings on Ti substrate with different morphologies and structures.Three kinds of typical topography of HA coatings,i.e.standing-up,flower and ordered porous structures have been obtained.The XRD and FTIR results demonstrate high crystallinity of the coating and exclusion of other forms of calcium phosphates.In vitro tests reveal that the biological property is largely dependent on the structure and morphology of the HA coating.It has been found that all pure HA coating show good biocompatibilities,while only the HA coating with ordered porous structures exhibits best bioactivities.

The Electrocatalystic Investigation Of 3,4-Dihydroxybenzoic Acid On The Modified Multiply Wall Carbon Nanotubes, Ming-Qi Li

Journal of Electrochemistry

The electrochemical behavior of 3,4-Dihydroxybenzoic acid(DHBA)on modified multiply wall carbon nanotubes electrode was investigated by cyclic voltammetry(CV) and square wave voltammetry(SWV).Results show that in 0.1 mol/L HCl solutions the modified carbon nanotube electrode has an obvious electrocatalytic effect on the oxidation and deoxidization of DHBA.The oxidation current of DHBA is linear to it's concentration in the range of 4.0×10~(-6)～1.0×10~(-4) mol/L and 2.0×10~(-4)～8.0×10~(-4)1mol/L with correlation coefficient of 0.9995 and 0.9992.The detection limit is 1.0 ×10~(-6)mol/ L.

High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2005 Through September 30, 2005, Anthony Hechanova

Publications (NSTD)

Quarterly Collaboration Meeting. The University of California, Berkeley, hosted a UNLVRF HTHX Project quarterly meeting on September 12. The purpose of the meeting was to promote collaboration and communication among the UNLV Research Foundation partners. Collaborators discussed their research program plan and provided an update on their progress. The next meeting will be in December in Las Vegas, NV hosted by UNLV.

Systematic, Multisite Short-Range-Order Corrections To The Electronic Structure Of Disordered Alloys From First Principles: The Kkr Nonlocal Cpa From The Dynamical Cluster Approximation, D. A. Biava, Subhradip Ghosh, Duane D. Johnson, W. A. Shelton, Andrei V. Smirnov

Duane D. Johnson

Although the Korringa-Kohn-Rostoker coherent-potential approximation (KKR-CPA) is used widely to configurationally average and get electronic structures and energies of disordered alloys, a single-site CPA misses local environment effects, including short-range order (SRO). A proposed nonlocal CPA (NLCPA) recovers translational invariance of the effective medium via k-space coarse graining from the dynamical cluster approximation (DCA), where corrections are systematic as cluster size increases. We implement a first-principles KKR-NLCPA/DCA and show the effects of environment, including SRO, on the electronic structures of fcc CuAu and bcc NiAl.

The Research Of Nano-Sized Nio Anode Materials For Lithium Ion Batteries, Jun-Mei Yan, Jing Zhang, Yong Yang

Journal of Electrochemistry

The nano-sized NiO materials were synthesized by solid phase method and sol-gel method. The synthesis conditions were optimized by DSC and TG techniques. The sol-gel method was optimized by changing the solvent and regulating the solution's pH for preparing NiO material. The structure and morphology of the materials were also characterized by means of XRD and TEM techniques, and the electrochemical performances of the materials were studied by the galvanostatically charge and discharge experiments.

Adsorption Of Polyaspartic Acid From Sulphur Acid Solution On Carbon Steel And Its Corrosion Inhibition, Rong-Jing Cui, Ning Gu, Chun-Mei Li

Journal of Electrochemistry

The role of Polyaspartic acid in the corrosion inhibition of 45~(#) carbon steel in sulphuric acid solution has been investigated by polarization curve andelectrochemical impedance spectroscopy (EIS). The influences of the concentration and the temperature of PASP on the corrosion inhibition efficiency were determined. The results indicated that the PASP as the corrosion inhibitor mainly inhibitated the anode; within the experiment temperature, the inhibitor efficiency decreased with the raising of the temperature and PASP had a good inhibiting performance at 10℃, the corrosion inhibition efficiency of PASP for carbon steel increased with the increase of the concentration of PASP when …

Electrocatalytic Oxidation And Degration Of Active Red X-3b By Nanotubes Catalytic Electrodes, Yi Wen, Jian-Hui Fang

Journal of Electrochemistry

The catalytic splitting decomposition of carbon nanotubes isprocessed by dispersing with dilute nitric acid and thermal oxidation. Then well-proportionedphenolic resin is mixed in the carbon nanotubes. Then, the carbon nanotubesare made into electrodes by hot-press molding after the process of milling with high speed. The surface of the carbon nanotubes electrodes is analyzed by SEM. Active red X-3B simulated waster water is disposed by carbon nanotubes catalyticelectrode (anode) and stainless steel(cathode). The influencing factors of degradation by current density, concentrationof electrolyte, systemtemperature and pH are investigated. The experimental results indicated that acidiccondition is propitious tothe degradationreaction of organicdyestuff and wastewater …

Effect Of Sintering Temperatures On Synthesis Of Mgco_(0.4)Mn_(1.6)O_(4 ) Positive Materials In Magnesium Ion Battery, Xiu-Ling Gao, Li-Fang Jiao, Hua-Tang Yuan

Journal of Electrochemistry

The cathode material MgCo_(0.4)Mn_(1.6)O_(4 ) for magnesium ion battery was synthesized by sol-gel method. The TG-DTA and XRD analyses showed that the prepared samples has simple spinel structure. Effect of annealing temperature on electrochemical properties was researched.The result shows that the sample sintered at 700℃ has the best electrochemical properties.

Nafion Emulsion Method For Fuel Cell Membrane-Electrode-Assembly Preparation, Chao-Yang Xia, Lin Zhuang

Journal of Electrochemistry

A Nafion emulsion method for fuel cell membrane-electrode-assembly (MEA) preparation was reported for the first time in this paper. 5 %(by mass) Nafion alcohol solution and non-polar solvent (e.g., cyclohexane) were ultrasonicallymixed to produce Nafion emulsion. The catalyst ink prepared using the thus-obtained Nafion emulsion can be directly cast onto Nafion membrane to make MEA. This method is simple in operation, and effectively preventsthe Nafion membrane swelling, hence is suitable for large-scale application. The MEA thus-prepared showed comparable catalyst efficiencywith respect to the popular transfer-method, and the preliminary performance in room-temperature H_(2)/O_(2 )fuel cell test was satisfying.

Effects Of Aluminide And Platinum-Aluminide Coatings On The Hot Corrosion Behavior Of Mar-M247 Nickel-Based Superalloy, I.K. Lee

Journal of Electrochemistry

This study is to investigate the high temperature hot corrosion behavior of aluminide coating and platinum-aluminide coating on Ni-base superalloy MAR-M247. On the platinum-aluminide, aluminide and the base metal, respectively, by the salt spraying method. The resistances to hot corrosion of platinum-aluminide coating, aluminide coating and the base metal were evaluated by the variations of weight gains. Aluminide and platinum-aluminide coating showed significanty beneficial effect on inhibiting the hot corrosion of MAR-M247. But that of the platinum-aluminide coating was even much better. The aluminide coating surface was composed of β-NiAl, and that of the platinum-aluminide coating was PtAl_(2). Both two …

The Growth Of Aluminide-Layer During The Hot-Dipping Al-(Si ) Coating Onto 430 Stainless Steels, Peng-Chicao Chen

Journal of Electrochemistry

The 430 stainless steels have been hot dipped in the molten Al-6.5%Si melts from 680 to 800℃, respectively. The effects of the hot dipping temperature and time on the thickness of the internal alloy layer have been investigated. The activation energy of the growth kinetic of aluminized layer was also calculated. The results showed that the thickness of aluminized layer increased with increasing dipping time and temperature. Besides, the growth kinetic of aluminized layer obeys parabolic rate law. The FeAl_(3 )and Fe_(2)Al_(5 )were formed by the inward diffusion, and the interface of intermetallic layer will be rugged and rough at …

The Application Of Astm C1202-93 On Evaluating The Performance Of Anti-Corrosion Of Concrete, Yuan Chen Yuan

Journal of Electrochemistry

The test of chloride ion penetration based on the standards of ASTM C1202-93 is applied to evaluate the anti-corrosion performance of concrete in this research. Concrete specimens were produced according to ACI 318-89 mixture proportioning design and the Desenfied Mixture Design Algorithm (DMDA) and were measured the 6-hour coulombs at the age of 91 days. Results show that w/b is not the factor influencing chloride penetration of ACI concrete, as the ion penetration of ACI specimens is all higher than 2 000 Coulombs and can even be poorer than 10 000 Coulombs. With a proper amount of pozzolanic material, the …

A Conjugate Dissolution / Deposition Behavior In Thin Layer Electrodeposition, Sun Bin

Journal of Electrochemistry

During the electrodeposition of lead, the dendrite deposit segregates from the cathode due to the disturbance of hydrogen gas. The segregated deposit could move toward the anode spontaneously rather than keep stationary. The studies show that this novel phenomenon was caused by the conjugate electrodissolution and electrodeposition reactions taking place at two ends of the isolated segment of the deposit. The mechanism inducing this phenomenon is suggested.

Electrochemical Reduction Characteristics Of Nitrobenzene At The Copper Electrode, Jin-Hong Fan, Wen-Ying Xu, Ting-Yao Gao

Journal of Electrochemistry

The electrochemical reduction characteristics and transition steps of nitrobenzene aqueous solution at the copper electrode, as well as its reduction mechanism were extensively investigatedby using the techniques such as cyclic voltammetry(CV) and linear scan voltammetry(LSV). The results showed that the reduction peaks of nitrobenzene at the copper electrode were located at 0.58 V and 1.32 V or so (vs. SCE), both acidity and alkalinesolutionsfavoredthe reduction of nitrobenzene. The adsorption of compounds followed by the reduction process, which is controlled by the mass transfer step at higher nitrobenzene concentration. In addition, the higher anaerobic degree led to faster reduction rate.