Engineering Science and Materials Commons^™

Ultrasonic And Stereo-Optical Characterization Techniques For Applications In Mechanical Testing, Jonathan M. Hein

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

This thesis considers methods developed based on ultrasonic reflections from interfaces and stereo-optical surface strain measurements to study the mechanical characterization of materials and bodies. The ultrasonic method is used to characterize wave speed and attenuation for highly attenuating samples. The stereo-optical strain measurements are used to characterize the effects of genes on mechanical properties of bone, and the dynamic characterization of blast waves in the UNL Shock Wave Trauma Mechanics facility.

A method is described and developed for characterizing the wave speed and attenuation spectrums from reflected waves from the contact surface with an unknown material. The method is …

Numerical Prediction Of The Haemodynamic Impact Of Coronary Stent Implantation, Jonathan Murphy

Doctoral

Arterial restenosis limits the effectiveness of coronary stenting. Restenosis is caused by excessive tissue growth which is stimulated by arterial injury and alterations to the arterial WSS. The altered WSS results from stent-induced disturbances to the natural haelnodynamics of the artery. Recent numerical studies have predcted only minor digerences in altered WSS between different stent designs using a commonly employed threshold assessment technique. While it is possible that there are only minor differences, it is more likely that the assessment technique is incapable of fully elucidating the altered WSS created by stent implantation. This thesis proposes a methodology that involves …

Tool Life Of Various Tool Materials When Friction Spot Welding Dp980 Steel, Christopher Shane Ridges

Theses and Dissertations

In this study, friction spot welding was used to join DP980 steel sheet. Four different ultra-hard tool materials were used with the objective of determining which tool material produced the highest number of acceptable-strength welds. Three of the tools were composed of various mixtures of polycrystalline cubic Boron Nitride (PCBN), Tungsten, and Rhenium. These materials are referred to herein as Q60, Q70, and Q80, the "Qxx" designation denoting the percentage of the volume of the tool material composed of PCBN. The fourth tool tested was composed entirely of PCBN. The Q70 tool produced approximately 1100 welds of acceptable strength before …

Material Reduction In Corrugated Containers For The Fresh Produce Industry, Justin Patterson

Industrial Technology and Packaging

In the fresh produce industry, corrugated containers must be made to provide adequate protection throughout the product life cycle. In response to increasing materials costs in the corrugated industry, companies are focusing upon developing more efficient packaging designs.  The scope of this project focuses on presenting alternative corrugated packaging designs for the fresh produce industry.  Included are one piece designs, three piece bliss designs and alternative material exploration.  This project presents the performance of new solutions by exploring their compressive strength before and after exposure to humidity.

Me-Em Enewsbrief, March 2011, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Waves In Microstructured Solids: A Unified Viewpoint Of Modelling, Arkadi Berezovski, Juri Engelbrecht, Mihhail Berezovski

Publications

The basic ideas for describing the dispersive wave motion in microstructured solids are discussed in the one-dimensional setting because then the differences between various microstructure models are clearly visible. An overview of models demonstrates a variety of approaches, but the consistent structure of the theory is best considered from the unified viewpoint of internal variables. It is shown that the unification of microstructure models can be achieved using the concept of dual internal variables.

Prepartion And Characterization Of Spr Au Substrate Using Wet Chemical Plating, You-Chen Zhou, Yan-Yan Wang, Zhi-Fang Ma, Yan-Xia Jiang, Jin Qiu, Shi-Gang Sun

Journal of Electrochemistry

The present study developed a preparation method of SPR gold substrate based on water phase operation.Firstly,on the glass modified by APTMS we self-assembed a gold colloid monolayer as the catalyst bed;Secondly,using the chemical plating technique,we made the gold film increase equably within the namometer range to obtain the proper shape and thinkness of the gold film required by the SPR.The analysis results of UV-vis and TEM demonstrated that the diameter of the monolayer formed from gold nanoparticles was 2.5 nm.Moreover,SEM showed that the nanoparticle prepared by electroless gold plating was uniformly distributed,whose diameter was 40 nm.The SPR flow injection experiment …

Preparation And Electrochemical Properties Of Sn Thin Film As Anode Materials For Lithium-Ion Batteries, Hong-Mei Bai, Zhan-Liang Tao, Fang-Yi Cheng, Jun Chen

Journal of Electrochemistry

Sn thin films as the anode materials of Li-ion batteries were prepared by vacuum-evaporation method on the copper foam substrate. The phase structure,surface morphology and electrochemical property of the as-prepared films were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM), and galvanostatic cycling. The results showed that three-dimensional structure of copper foam substrate enhanced the adhesion strength between the active material and the substrate, under the same substrate temperature, the particles became bigger with the increasing of evaporation time, while their electrochemical property decreased, under the same evaporation time, the particles didn′t changed obviously with the increasing of substrate temperature,while their cycle …

Electrochemical Double-Layer Capacitors Using Phenolic Resin-Based Carbon Fibers, Rong Xue, Jing-Wang Yan, Ying Tian, Bao-Lian Yi

Journal of Electrochemistry

Phenolic resin-based activated carbon fiber(ACF) was prepared by KOH activation.The electrochemical properties of pulverized phenolic resin-based carbon fiber(P-ACF) were examined in 6 mol·L^-1 KOH compared with that of the original ACF.P-ACF exhibited a better capacitive behavior and showed a larger specific capacitance(200 F·g^-1) as well as a lower capacitance decrease at high current densities.The pore resistance for ion migration(Rp) in P-ACF was lower(2.96 Ω) than that in ACF(4.65 Ω).Pulverization increased the exposure of the cross section,lowered the contact resistance between the carbon fibers and decreased the pore resistance for ion migration.

Low-Temperature Performance Of Li-Ion Battery With Fluoroethylene Carbonate Electrolyte, Chun-Wei Yang, Feng Wu, Bo-Rong Wu, Yong-Huan Ren, Jing-Wen Yao

Journal of Electrochemistry

The low temperature performance of electrolytes containing FEC including FEC+EMC, EC and PC, as well as the compatibility of electrolytes with LiFePO₄ anode and with MCMB cathode were investigated.The electrolyte exhibits a high value of ionic conductivity at low temperature.The stability of cathode was enhanced by the formation of SEI film at 1.6 V as a result of FEC reaction. The infrared spectra showed that FEC can suppress decomposition of other solvents during SEI formation, and lower the resistance of SEI on MCMB cathode. The electrochemistry test indicates that Li-ion batteries with FEC electrolyte display high capacity at low …

Influence Of Electric Field On The Adsorption And Bioactivity Of Hemoglobin On A Macroporous Gold Electrode, Cui-Hong Wang, Yi-Bing Kong, Xing-Hua Xia

Journal of Electrochemistry

The adsorption and bioactivity of proteins at interfaces have been widely studied due to their important role in the construction of biosensors,bioelectronics and biofuel cells.Interfacial electric field is one of the important factors which could affect the adsorption and bioactivity of proteins at materials surfaces.It could dramatically change the adsorption density,molecular conformation and orientation at material surfaces.In this paper,the influence of interfacial electric field on the adsorption kinetics and bioactivity of hemoglobin(Hb) on a three-dimensional(3D) macroporous gold electrode surface has been studied using electrochemical methods and infrared spectroscopy.It was found that the interfacial electric field created excess surface charge which …

Synthesis Of Mesoporous Nickel Oxide For Supercapacitor Application, Xuan-Xuan Chen, Zhen-Zhen Zhao, Deng-Chao Wang, Zhong-Jie Huang, Wen-Bin Ni, Li Yu, Jian-Wei Zhao

Journal of Electrochemistry

Mesoporous nickel oxide has been synthesized by calcining metal-organic coordination precursor.Transmission electron microscopy and BET test showed that the prepared NiO had a regular morphology and displayed a narrow size distribution.Electrochemical tests revealed that such mesoporous NiO had a specific capacity of 72 F·g^-1 at the current of 2.0 A·g^-1.Futhermore,the material showed excellent cycle-life stability.There was no degradation of capacitance after 1000 cycles.

A Titanium-Supported Nanoporous Pd Electrocatalyst For Methanol Oxidation, Feng-Juan Niu, Qing-Feng Yi

Journal of Electrochemistry

Titanium-supported nanoporous palladium electrode(nanoPd /Ti) was prepared by a hydrothermal process in the presence of the ligand EDTA and using formaldehyde as reducing agent.SEM images showed that the size of Pd particles was about 60 nm and the Pd particles were connected with each other to form a three-dimensional network structure.Cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were applied to evaluate the electrocatalytic activity of the nanoPd/Ti electrode towards methanol oxidation in alkaline solution.CV results showed that the nanoPd /Ti electrode presented high anodic peak densities and a low onset potential for methanol oxidation.Also nanoPd /Ti electrode showed excellent CO tolerance …

Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng

Journal of Electrochemistry

The electrochemical behavior and electrocatalytic oxidation of hydrazine on rutin multiwall carbon nanotubes modified glassy carbon electrode were studied by cyclic voltammetry.The experimental results indicated that the electrode exhibits good electrocatalytic activity to hydrazine at a reduced oxidation potential of 262 mV.The amperometric response of the modified electrode showed linear increase after successive addition of hydrazine in the concentration range of 2.5×10^-6~1.0×10^-4 mol·L-1 with a detection limit of 5×10^-7 mol·L^-1.

Applications Of Raman Spectroscopy Technique In Lithium Ion Batteries, Liang Zhao, Yong-Sheng Hu, Hong Li, Zhao-Xiang Wang, Hong-Xing Xu, Xue-Jie Huang, Li-Quan Chen

Journal of Electrochemistry

The Raman spectroscopy has been widely used in the study of lithium ion batteries.In this short review,we gave some examples of the applications of Raman spectroscopy in the study of electrode materials including carbonaceous materials,spinel LiM_xMn_2-x O₄,LiFePO₄,as well as polymer electrolytes,room temperaturemolten salt electrolytes and the solid-electrolyte interphase layers.The advantages and disadvantages of the ex-situ and in-situ Raman spectrum techniques are discussed.Using new Raman techniques to investigate Li-ion batteries are suggested.

Novel Anion Exchange Membranes Base On Copolymer Of 2-(Diethylamino) Ethyl Methacrylate And Fluoro-Polyacrylate For Alkaline Direct Methanol Fuel Cells, Yan-Mei Zhang, Jun Fang, Ge Yan, Yong-Ze Zhuang

Journal of Electrochemistry

Anion exchange membrane fuel cells,which use anion exchange membranes as polyelectrolytes,have attracted more and more research interests recently.In this work,a series of hydroxyl-conducting anion-exchange membranes based on the copolymer of 2-(Diethylamino)ethyl methacrylate and fluoro-polyacrylate were prepared by radical polymerization,and their potential applications in alkaline fuel cells were assessed.It was shown that the ionic conductivity of the membranes reached 10^-2 S·cm^-1 at room temperature,while the methanol permeability was lower than 10^-7 cm²·s^-1.The maximum power density of fuel cell assembled with this membrane was achieved to be 43.2 mW·cm^-2 at room temperature,indicating possible application …

Electrooxidation Of Methanol On Multilayer Films Of Polypyrrole-Platinum Electrode, Ling Zhang, Long-Zhen Zheng

Journal of Electrochemistry

Multilayer films of polypyrrole-platinum electrode were fabricated by cyclic voltammetric technique.Electro-oxidation of methanol on this electrode was investigated with the aid of cyclic voltammetry and chronoamperometry.Results demonstrated that the multilayer of polypyrrole-platinum electrode behaved better electrocatalytic performance for electro-oxidaton of methanol and better poison resistant.Furthermore,with the increase of deposited platinum loadings,the rate controlling step on electro-oxidation reaction of methanol was changed from CO oxidation to sorption-desorption of hydrogen.

Electrochemical Capacitive Performance Of Polyaniline Electrode With Different Electrolytes, Yong-Tao Tan, Fen Ran, Ling-Ren Wang, Ji Liu, Ling-Bin Kong, Yong-Chun Luo, Long Kang

Journal of Electrochemistry

The polyaniline(PANi) for supercapacitor was prepared by chemical-oxidative polymerization.The SEM,FTIR data and electrochemical performance showed that,polyaniline nanoparticles were formed which were about 50 nm;the specific capacitances of PANi were 404 F/g,208 F/g and 279 F/g in 1 mol/L H₂SO₄,NaNO₃ and KOH,respectively,when the current density was 5 mA/cm².The concentrations of H₂SO₄ increased to 2 mol/L or 6 mol/L,the capacitances decreased to 330 F/g or 248 F/g.

Electrochemical Deposition Of Zinc Oxide Crystal Whiskers, Peng-Zeng Lu, Su Li, Jin-Qian Jia, Zhen-Hai Liang

Journal of Electrochemistry

Pine needle ZnO crystal whiskers were electrodeposited by anodization of zinc foil.The crystal whiskers were characterized by scanning electron microscopy(SEM) and X-ray diffraction(XRD) spectroscopy.The results show that the lengths and diameters of ZnO crystal whiskers are 200~300 nm and 20~50 nm,respectively,with the ratio of the length to diameter ranging from 10~15.The whiskers belong to wurtzite ZnO(JCPDS 36-1451) with good crystallinity and high purity.The crystalization behavior of ZnO was studied by cyclic voltammetry.The effects of the surface oxide layer at the zinc substrates and the [Zn(OH)₄]^2-concentration of the aqueous electrolyte on the formation of zinc oxide whiskers …

On The Stability Of A Microstructure Model, Mihhail Berezovski, Arkadi Berezovski

Publications

The asymptotic stability of solutions of the Mindlin-type microstructure model for solids is analyzed in the paper. It is shown that short waves are asymptotically stable even in the case of a weakly non-convex free energy dependence on microdeformation.