Engineering Science and Materials Commons^™

Electrochemical Behavior Of Zinc Alloy Anode In Ca(Oh)2 Solutions Of Different Ph, Peng-Ying Ren, Ji-Quan He

Journal of Electrochemistry

The polarization curves of zinc alloy anodes in Ca(OH)₂ solutions have been measured by potentiodynamic method,and the composition of corrosion products were examined by X-ray-diffraction(XRD).The experimental results indicated that not only the electrochemical behavior of zinc alloy anodes were absolutely different in every alkaline solutions,but also many electrochemical parameters were determined,such as zero current potential(E0),the density of corrosion current(icorr),passive current density(ip),breakdown potential(Eb),and so on.There were three zero current potential when zinc alloy anodes in some Ca(OH)₂ solutions which made passive state unstable.The graphs of E-pH about zinc alloy anodes dipped in different Ca(OH)₂ solutions were drawn,and compared …

Study On Electrochemical Impedance Spectroscopy Of Carbon Steel Eroded In Methyldiethanolamine Solution, Dong-Ping Wei, Rong-Zong Hu, Dan-Mei Pan, Wei-Xiong Huang, Rui Dong

Journal of Electrochemistry

Corrosion behavior of carbon steel in methyldiethanolamine(MDEA) solution was investigated by Electrochemical Impedance Spectroscopy(EIS).The results were showed that the corrosion rate of carbon steel in solution containing dissolved oxygen is higher than that in solution removed of dissolved oxygen before cathodic activation.They were reversed after cathodic activation.The corrosion rate is increased at first and then decreased when the concentration of MDEA is increased in the blank solutions.In the simulated solutions containing quantities of!heat-stable salts(HSS),the corrosion rate is decreased monotonously with increase of the MDEA concentration.As anodic polarization potential is increased,the EIS of carbon steel in HSS simulated solution showed characteristics …

An Experimental Technique For The Evaluation Of Strain Dependent Material Properties Of Hard Coatings, Shad A. Reed, Anthony N. Palazotto, William P. Baker

Faculty Publications

A novel vibration experiment consisting of a free-free boundary condition, an electromagnetic excitation source, a vacuum chamber, and a laser vibrometer based surface measurement system has been developed that permits high levels of excitation on highly damped specimens with a minimal amount of unwanted systematic error. While some of the aspects of this experiment are not unique, when combined with a processing technique that accounts for the nonlinearities present in the system, this experiment permits, accurate measurement of strain dependent stiffness and damping properties of hard coatings at high strain levels. This procedure has been demonstrated using a titanium beam …

Cyclic Creep And Recovery Behavior Of Nextel™ 720/Alumina Ceramic Matrix Composite At 1200° C In Air And Steam Environments, Bridgett A. Whiting

Theses and Dissertations

The cyclic creep and recovery behaviors of the N720/Al₂O₃ composite were investigated in this research. The ceramic matrix composite (CMC) contains a porous alumina matrix with laminated, woven mullite/alumina (Nextel^TM 720) fibers. The composite does not have an interface between the fiber and matrix. The CMC relies on the porous nature for flaw tolerance. The objective of this study the influences of monotonic creep and cyclic creep loading histories on the creep lifetime, creep strain rate, accumulated creep strain as well as on the recovery of creep strain at near zero stress. The cyclic creep and …

Oxygen Enrichment Effect Of Mno2-Pt/C Compound Catalyst To The Cathode Of Pemfc, Hong-Feng Xu, Mao-Feng Zhang, Quan-Quan Gan, Cai-Sheng Huang

Journal of Electrochemistry

TO study of the oxygen storage material of air cathode is crucial for increasing performance of proton exchange membrane fuel cell.Using the MnO₂ as oxygen storage materials,a MnO₂-Pt/C catalysts were prepared and is used to replace the conventional Pt/C in air cathode.The electrochemical performance of air cathode composed of MnO₂ supported on Pt/C and the properties of fuel cell composed of MnO₂-Pt/C were investigated by using the CV,galvanostatic dischange method and TEM.

Growth Mechanism And Morphology Of Electrodeposited Micro-Nanocrystalline Iron, Qiao-Xin Zhang, Jia-Ming Zhang, Li-Ning Yang

Journal of Electrochemistry

Effects of current density,reaction temperature,electrolyte concentration and surfactant on the electrochemical deposition of micro-nanocrystalline iron were studied.Morphologies and structures of the samples were characterized by SEM and XRD,the results showed that the electrodeposits is slice α-Fe under little current and the density,lower temperature and higher concentration,and the dentritic α-Fe is under opposite conditions,but the influence from surfactant is unconsicously.Moreover,the growth mechanism of the electrodeposits was also analysed here.

Studies On Catalytic Mechanism Of Li/Socl2 Batteries By Metal Phthalocyanine Complexes, Zhan-Wei Xu, Qing-Jin Sun, Bi-Yun Su, Tu-Lin Che, Yan-Hong Song, Yao-Min Li, Jian-She Zhao

Journal of Electrochemistry

Effects of metal phthalocyanine comlexes MPc(M= Mn(Ⅱ),Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ)) as electrochemical catalysts on the performance of Li/SOCl₂ batteries have been examined at constant resistance.And the reasons of MPc affecting the discharged voltage and discharged time of Li/SOCl₂ batteries were also brought forward.A few new viewpoints on the catalytic mechanism of the reduction of thionyl chloride by phthalocyanine complexes were proposed.

Electro-Chemical Oxidation Kinetics Of The V(Iv) In The Sulfuric Acid Solution, Yong-Lian Qiao, Qian Xu, Jie Zhang, Yu-Chun Zhai

Journal of Electrochemistry

The electro-chemical oxidation kinetics for V(IV) in the sulfuric acid solution were investigated by cyclic voltammetry and steady state polarization curves at a graphite,platinum or conducting polymer electrode.Some kinetics parameters for the electrochemical reaction of V(IV) were calculated according to the Tafel curves.The results showed that the exchange current density and reversibility of V(V)/V(IV) redox reaction at the graphite electrode is largest among the three electrodes.There is the broadest extent of water stability and large oxidgen evolution potential when the conducting polymer was used as a working electrode in the solution of VOSO₄(0.5 mol/L) and H₂SO …

Electro-Generated Mno2 In Supersonic Wave Bath And Its Application In Preparation Of Glyceraldehyde, Yan-Hong Cai, Li-Qun Chen, Ri-Yao Chen, Xi Zheng, Xiao Chen, Zhen Chen

Journal of Electrochemistry

Glyceraldehyde is prepared by using MnO₂/ Mn²⁺as the media in a cationic membrane electrolytic cell.Under ultrasonic high-frequency oscillation,the electro-generated nanometer MnO₂ dispersed in the solution with several tens nm till several micron.Then the MnO₂ is used for selective oxidation of glycerine to glyceraldehydes.The catalyzing selectivity of MnO₂/ Mn²⁺is high and the current efficiency may account to 97.4 %.

Electrocatalytic Separation For Dopamine And Ascorbic Acid Using Poly-Evans Blue Modified Glassy Carbon Electrode And Simultaneous Determination, Li-Qing Lin, Xin-Hua Lin, Hong Yao, Jing-Hua Chen, Guang-Wen Li

Journal of Electrochemistry

Voltammetric behavior of the Dopamine(DA) and ascorbic acid(AA) at Poly-Evans Blue modified electrode were studied and a novel method for determination of the content of DA and AA is established.In pH 4.5 phosphate buffer solution,the modified electrode shows enhanced sensitivity and excellent electrochemical discrimination to DA and AA.The relationship between oxidation peak current and the concentration of DA or AA is linear in the range of 1.0 10^-6 ～3.0×10^-5mol/L and 5.0×10^-6~1.05×10^-4 mol/L,the detection limit has been estimated as 2.5(10^-7 mol/L and 3.0 ×10^-7 mol/ L,respectively.The oxidable potential difference of DA and AA …

Prerapation And Supercapacitor Property Of Al Doped Co3O4, Xin Ge, Ye Chen, Chun-Xia Zhang, Chang Shu

Journal of Electrochemistry

With KOH as precipitator to prepare Aluminum doped Co₃O₄,X-ray diffraction indicated that the doping Al did not change the crystal structure of Co₃O₄.Electrochemical properties of the sample were tested by cyclic voltammetry and constant-current charge/discharge.The results showed that the chemical doping improved the specific capacitance.When the mol ratio of Co(Ⅱ) with Al(Ⅲ)was 1∶0.05,the specific capacitance was up to 518.07 F/g within 0～400 mV potenitial at current density 5 mA/cm².

Preparation Of Manganese/Chromium Hexacyanoferrate Modified Glassy Carbon Electrode And Its Electrochemical Behavior, Sheng-Tao Zhang, Xiao-Yan Han, Ming-Yue Xue

Journal of Electrochemistry

A film of poly(manganese/chromium hexacyanoferrate)(MnCrHCF)is formed on the glassy carbon electrode(GCE) by Cyclic Voltammetry scanning,and its electrochemical behavior was studied.Factors affecting the electro-deposition of the film such as pH values and sustaining electrolytes,were discussed.And mechanism of the reaction was investigated.

Influence Of Chromium On The Semi-Conductive Property Of Passive Film Formed On Carbon Steel In Bicarbonate/Carbonate Buffer Solution, Jin-Bo Li, Jie-Wu Zhu, Mao-Sheng Zheng

Journal of Electrochemistry

The influence of chromium on the semi-conductive property of the passive film formed at carbon steel in bicarbonate/carbonate buffer solution,is investigated by using electrochemical impedance spectroscopy(EIS).The results showed that the passive film fomed at carbon steel appeared an n-type semi-conductive property,but if the passive film formed at carbon steel with 3% chromium content exhibited an a-p semi-conductive charatcer.The slopes of Mott-Schottky plot of two passive films increased with rising the formation potential,it indicating the defect density of the film decreasing,but for the passive film formed at carbon steel with chromium additive,its donor density was lower about one order of magnitude …

Fabrication And Charaterization Of Nitrogen-Doped Tio2 Nanotube Array And Its Visible Light Activity, Hui-Fang Zhuang, Yue-Kun Lai, Jing Li, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Nitrogen-doped TiO₂ nanotube array was fabricated by an electrochemical anodic oxidation followed a wet process.XPS result indicates that the nitrogen atoms were doped into lattice of TiO₂ nanotubes.The UV-Vis spectra show that the photoabsorption of N-doped TiO₂ nanotube array film is enhanced in the visible light region.Compared with the TiO₂ nanotube array film,the N-doped TiO₂ nanotubes exhibite a higher photocatalytic activity which is evaluated by the decomposition rate of methyl orange using the tungsten-halogen lamp as light source.

Preparation, Structure, And Cv Study Of The Supported Ptruir/Tic Electrocatalysts For Oxygen Electrodes, Sheng Sui, Li-Rong Ma

Journal of Electrochemistry

The PtRuIr/TiC electrocatalysts were prepared by method of reduction and deposition on TiC powders as supports together with ultrasonic wave dispersion.The sampls were characterized by BET surface area,scanning electron microscope,X-ray diffraction,and cyclic voltammetry techniques.The active components of Pt,Ru,and Ir particles(2.6%Pt,1.3%Ru,16%Ir,and 80%TiC,by mass) were mainly dispersed on the outer surface of the TiC supports,which structures were in favor of fine variable crystallites.It was found that the electrochemical performance of the PtRuIr/TiC electrodes was about three times as that of the unsupported electrocatalysts with the same active compositions for oxygen evolution reaction.After 120 times of CV cycles,there was almost no PtRuIr/TiC dissolving …

Electrocatalytic Oxidation Of Methanol At The Nano Ni-B Amorphous Alloy Powdermicroelectrode, Yi-Xiong Zheng, Shi-Bing Yao, Shao-Min Zhou

Journal of Electrochemistry

Electrocatalytic oxidation of methanol at the nano Ni-B amorphous alloy powder-microelectrode in alkaline media was studied by using cyclic voltammetry.Compared to the highly preferred orientation(220) nickel electrode,The onset potential of methanol electrooxidation at the nano Ni-B microelectrode is negatively shifted about 0.04V,and the current density is increased approximately by 2 orders of magnitude.Thus,the nano Ni-B microelectrode has very strong electrocatalytic activity for the oxidation of methanol.The kinetic parameters were determined with the steady polarization curves.The results show that the rate constants for both the oxidation of Ni(Ⅱ) to Ni(Ⅲ) and the reduction of Ni(Ⅲ) to Ni(Ⅱ) at the nano Ni-B …

The Syntheses And Electrochemical Performance Of Nano-Mno2 For Supercapacitor, Jun Ma, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

Nano-manganese dioxide were prepared by two different methods which are low temperature solid reaction and chemical deposition.The products were characterized by XRD,SEM,BET and constant current charge-discharge tests.The result shows that there is a close relationship between specific capacitance and BET surface areas.Meanwhile the specific capacitance was impacted little by the structure of the nano-manganese dioxides.However,the product performance of high rates,was influenced by structure,the higher rate can be obtained with the more perfect crystal structure.

Morphology Of The Pb-Sn Alloy Thin-Layer Electrodeposition, Yan-Jun Du, Zhi-Gang Yin, Tong-Chi Xia

Journal of Electrochemistry

The morphology of Pb-Sn alloy thin-layer electrodeposition was studied.Experimental results showed that the morphology of deposit could vary as the concentration of Pb²⁺, Sn²⁺ two kind metallic ion to be changed.The patterns of product appeared the dendritic, ramification, dense branch, fractal, and homogeneous structure and their morphological evolution was caused by the change in anisotropy of crystal growth and different stage of electrodeposits.

Effect Of Tension On Corrosion Behavior Of Galvanized Steel Wire For Cable-Stayed Bridge, Xue-Ming Li, Jie-Min Zhou, Qiang Liu, Ling-Feng Kong, Jian-Ting Zhou

Journal of Electrochemistry

Corrosion of steel wire in cables is a major cause of cable-stayed bridge deterioration. The corrosion behavior of galvanized steel wire at different tension is investigated by polarization voltammetry method and neutral salt spray test in 5% NaCl solution. The physical and chemical properties of corrosion products are characterized by XRD and TG-DTA.The result shows that the corrosion current or corrosion rate of galvanized steel wire is larger with increasing the tension, the white rust of galvanized steel wires at different tension appears within one cycle, the red rust appears after 16 cycles at 15~22kN tension, and 23 cycles at …

Exact Solution Of Time History Response For Dynamic Systems With Coupled Damping Using Complex Mode Superposition, Manoj Kumar Chinnakonda

All Theses

An exact solution method for general, non-proportional damping time history response for piece-wise linear loading proposed by Dickens is generalized to piece-wise quadratic loading. Comparisons are made to Trapezoidal and Simpson's quadrature rules for approximating the time integral of the weighted generalized forcing function in the exact solution to the decoupled modal equations arising from state-space modal analysis of linear dynamic systems. The time integral of the forcing function is recognized as a weighted integral with complex exponential and the general update formulas are derived using polynomial interpolation to the forcing function. Closed-form expressions for the weighting parameters in the …

Registration Using Graphics Processor Unit, Koushik Aravalli

All Theses

Data point set registration is an important operation in coordinate metrology. Registration is the operation by which sampled point clouds are aligned with a CAD model by a 4X4 homogeneous transformation (e.g., rotation and translation). This alignment permits validation of the produced artifact's geometry. State-of-the-art metrology systems are now capable of generating thousands, if not millions, of data points during an inspection operation, resulting in increased computational power to fully utilize these larger data sets. The registration process is an iterative nonlinear optimization operation having an execution time directly related to the number of points processed and CAD model complexity. …

Simulation Of A Backrest Moment Test For An Automotive Front Seat Using Nonlinear Contact Finite Element Analysis , Abhinand Chelikani

All Theses

Computer aided engineering and finite element simulation are essential in order to predict accurately the safety performance of automotive structures in an event of crash. In this work, finite element simulation is used to evaluate the strength and deflection characteristics of a reference automotive front seat in an event of vehicle rear impact. Understanding the strength-deflection characteristics of front automotive seats during vehicle rear impact is important to ensure the safety function of the seat. The safety function is measured based on a moment test in accordance with government (ECE R17) regulations. Accurate finite element modeling of a reference seat …

A Hydraulic Actuated Thermal Management System For Large Displacement Engine Cooling Systems, Peyton Frick

All Theses

The performance of automotive cooling systems can be improved by replacing the traditional mechanically driven radiator fan and water pump assemblies with computer controlled components. The introduction of electric servo-motors to drive the cooling components can improve temperature tracking, which should increase fuel efficiency and decrease tailpipe emissions. However, the power requirement for these electric motors increases with greater cooling demands if the radiator surface area remains constrained. For heavy-duty applications, where engines are subjected to significant cooling loads, electric motors may become impractical due to their increased size and power requirements; in these situations, hydraulic-based components are advantageous due …

Effects Of Aggregates On Properties And Performance Of Mastics And Superpave Hot Mix Asphalt Mixtures, Francisco Aragão

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Superpave, a set of advancements in testing devices and specifications for asphalt binders and mixtures, was limited to address the effects of aggregates. Because aggregates represent around 95% in mass of the asphalt mixtures, it is important to understand how these materials affect properties and performance of such mixtures. This research focus on how different types and contents of aggregates affect properties of mastics and asphalt mixtures, and their performance considering the viscoelastic nature of the asphalt material.

Five different types of aggregates and hydrated lime were used for sample fabrication together with two different binders. Several different tests were …

Advanced Thermal Management For Internal Combustion Engines, Thomas Mitchell

All Theses

The automotive cooling system has unrealized potential to improve internal combustion engine performance through enhanced coolant temperature control and reduced parasitic losses. Advanced automotive thermal management systems use controllable actuators (e.g., smart thermostat valve, variable speed water pump, and electric radiator fan) in place of conventional mechanical cooling system components to improve engine temperature tracking over most operating ranges. To optimize advanced cooling system performance, the electro-mechanical actuators must work in harmony to control engine temperature. The design and placement of cooling components should also be considered when attempting to maximize the performance.
In this research project, two distinct vehicle …

Development Of A Microscopic Moirž Interferometry System, Jeremy Brougher

All Theses

The human tooth is an amazing structure that is worthy of detailed research and analysis. For over half a century, various tests have been conducted to acquire more information about the structural and material properties of dentin, enamel, and the dentin-enamel junction. Unfortunately, variations still exist in the experimental results, even in the most recently collected data. The primary focus of the majority of material property testing on human teeth has been hardness testing utilizing indentation and nanoindentation analysis. However, several limitations still exist with the indentation technique. Thus, the moirŽ fringe analysis method, specifically microscopic moirŽ interferometry, has been …

Nonlinear Modeling Of The Adsorption-Induced Surface Stress In Piezoelectrically-Driven Microcantilever Biosensors, Mana Afshari

All Theses

Microcantilever-based biosensors are rapidly becoming an enabling sensing technology for a variety of label-free biological applications due to their extreme applicability, versatility and low cost. These sensors operate through the adsorption of species on the functionalized surface of microcantilevers. The adsorption of biological species induces surface stress which originates from the molecular interactions such as adhesion forces of attraction/repulsion, electrostatic forces or the surface charge redistribution of the underlying substrate. This surface stress, consequently, alters the resonance frequency of the microcantilever beam.
This study presents a general framework towards modeling resonance frequency changes induced due to the surface stress arising …

Analyzing Relationships Between Lightning And Rain In Order To Improve Estimation Accuracy Of Rain , Justin Lapp

All Theses

The remote estimation of rainfall rate R is essential for the aviation industry, agriculture, and food warning. Radar, the current means of R estimation, is not available in much of the world. In addition, this measurement involves a level of inaccuracy. Using lightning to detect rain is a relatively inexpensive alternative to radar systems and can be done from existing satellites. Previous research has revealed correlations between lightning and rain, suggesting either that it is possible to estimate R using lightning, or that it is possible to use it to correct for a portion of the radar inaccuracies. These correlations …

Measurement And Analysis Of Hydromechanical Effects In Fractured Rock, Todd Schweisinger

All Dissertations

Fractures in rock hold important stores of water and petroleum, and slight changes in fracture aperture accompanying drawdown from pumping wells play a key role in recovering these resources. Four accomplishments are described that advance insight into the behavior and characterization of fractured crystalline rock.
First was the development of two removable borehole extensometers that enable small axial displacements to be measured during hydraulic well tests. The extensometers consist of four major components: 1.) a pair of anchors; 2.) a displacement transducer 3.) a registration system, and; 4.) a temperature-compensated reference rod. One extensometer uses an axial reference rod with …

Nonlinear Vibration And Frequency Response Analysis Of Nanomechanical Cantilever Beams, Seyed Nima Mahmoodi

All Dissertations

Microcantilevers are one the most commonly utilized microelectromechanical systems in a variant of the ultra-precise scanning and characterization application. Of particular interest, the problem of vibrations of microcantilevers has recently received considerable attention due to its application in several nanotechnological instruments such as atomic force microscopy, nanomechanical cantilever sensors and friction force microscopy. For applications such as these, the problem of coupled flexural-torsional nonlinear vibrations of a piezoelectrically-actuated microcantilever beam is considered in this dissertation. The actuation and sensing are both facilitated through bonding a piezoelectric layer (here, ZnO) on the microcantilever surface. The beam is considered to have simultaneous …