Engineering Commons^™

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 …

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 …

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 …

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 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 …

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 …

Numerical Simulation Of Waves And Fronts In Inhomogeneous Solids, A. Berezovski, M. Berezovski, J. Engelbrecht, G. A. Maugin

Publications

Dynamic response of inhomogeneous materials exhibits new effects, which often do not exist in homogeneous media. It is quite natural that most of studies of wave and front propagation in inhomogeneous materials are associated with numerical simulations. To develop a numerical algorithm and to perform the numerical simulations of moving fronts we need to formulate a kinetic law of progress relating the driving force and the velocity of the discontinuity. The velocity of discontinuity is determined by means of the non-equilibrium jump relations at the front. The obtained numerical method generalizes the wave-propagation algorithm to the case of moving discontinuities …

The Effects Of Environment On The Interlaminar Shear Performance Of An Oxide/Oxide Ceramic Matrix Composite At Elevated Temperature, Patrick D. Laffey

Theses and Dissertations

This research investigated the interlaminar shear performance of an oxide/oxide ceramic matrix composite consisting of Nextel™ 720 fibers in a high purity, porous alumina (Al₂O₃) matrix. The interlaminar shear performance was observed in both tension and compression of double notched specimens (DNS) at 1200 °C. Interlaminar shear creep behavior was examined in both laboratory air and in steam environment at 1200 °C. In air, the creep stress was -6.5 MPa. In steam creep stresses included -4.0, -5.0, and -6.5 MPa. Primary and secondary creep regimes were observed in all air creep tests and the creep test …

Effects Of Prior Aging At 191°C On Creep Response Of Im7/Bmi 5250-4, Robert A. Salvia

Theses and Dissertations

The creep behavior of IM7/BMI 5250-4 with fiber orientations of [± 45] and [0/90] that were aged in air at 191 °C for up to 1000 hours was evaluated. The total weight loss during the aging process was also evaluated. Weight loss due to aging was 0.64% for the [0/90] fiber orientation and 0.72% for the [± 45] fiber orientation. Tensile tests to failure were conducted to establish tensile properties. The [0/90] specimens have a much higher stiffness and Ultimate Tensile Strength (UTS) values than the [± 45] specimens. The tensile tests of the aged specimens revealed that the Ultimate …

Effects Of Prior Aging On The Creep Response Of Carbon Fiber Reinforced Pmr-15 Neat Resin At 288°C In An Air Environment, Christopher A. Back

Theses and Dissertations

The mechanical response of carbon fiber reinforced PMR-15 neat resin with a ± 45 fiber orientation was investigated at 288 °C. Mechanical testing was performed on unaged specimens and specimens that were aged up to 1000 hours in an air environment. Tensile tests were performed to determine Young's modulus of elasticity and Ultimate Tensile Strength. Creep tests were performed at creep stress levels of 30 and 60 MPa. Creep periods of at least 25 h in duration were followed by recovery at zero stress. Duration of the recovery period was at least twice the time of the creep period. Oxidation …

Compressive Creep Behavior Of Nextel™ 720/Alumina Ceramic Matrix Composite At 1200°C In Air And In Steam Environment, Neil R. Szymczak

Theses and Dissertations

The aerospace community continues to push the envelope in engineering aircraft that fly higher, faster, and safer while operating with a greater degree of efficiency. To meet these operational requirements innovative aerospace components must be designed to operate in aggressive environments. This research will investigate the ultimate compressive strength and the compressive creep behavior of Nextel^TM 720/Alumina ceramic matrix composite at 1200 °C in air and 100% steam environments. The effects of creep loading history on the tensile and compressive material behavior will also be examined. The primary strengths of the N720/A composite are its oxide/oxide composition which inherently …

Catalysis Of Nano Tio2 For Horseradish Peroxidase, Ya-Qi Zhu, Hai Wu, Hiu Liu, Jie Ma

Journal of Electrochemistry

Horseradish peroxidase immobilized on the surface of titanium dioxide nanoparticles and nanotube modified glassy carbon electrode.The HRP direct electron transfer reaction was compared between TiO₂ nanoparticles and nanotube GC electrode.The results demonstrated that the HRP on TiO₂ nanotube /GC electrode could catalyze electron exchange reaction between electroactivity center of HRP and electrode.And the research of antibody labeled HRP provides a selected signal for antibody-antigen immunoassay.

Electrochemical Reduction Of Coals And The Oxygenic Functional Simulacrums Of Coals, Juan Lin, Zhao Wei

Journal of Electrochemistry

Electrochemical reduction of coals and the oxygenic functional simulacrums of coals has been studied.In this process,tetrabutylammonium was used as supporting electrolyte.The coal and the deoxidized coal were extracted by methanol.Qualitative analysis of the deoxidized products and the extractives was carried out on gas chromatograph-mass spectrometer.The deoxidized products of the oxygenic functional simulacrums of coals were analysed quantitatively with gas chromatograph spectrometer.The results show that the oxygenic functional groups on the coals surface decrease and the translation ratios of the oxygenic functional simulacrums of coals need further increase after electrochemical reduction,.The electrochemical tests show simultaneously the kinetics equations of every related …

Study On The Electricity Capability Of Ru((0.4-X))IrXTi(0.6)/Ti Electrode, Ling-Li Wang, Qiao Peng

Journal of Electrochemistry

The metal oxide anode of Ru_(0.4-x)Ir_xTi_0.6 has been prepared by thermal decomposition.The results indicate that,when the percent of IrO₂ is 10%,the electrode has low chlorine potential,high oxygen potential and excellent catalyze selectivity;strengthen life is long with IrO₂ content increased from 1.0h to 97h.It shows that the electrode anti-oxide corrosion perform is improved and intensifying life is long with addition of IrO₂.The film and reaction resistance are all fall with the addition of IrO₂.The addition of IrO₂ is in favor of thin crystal and makes the film more roughness.

Study On The Characteristics Of Vb(12) Modified Electrode By Electropolymerization, Hui-Ting Lian, Wen-Ji Wang

Journal of Electrochemistry

Preparation of the VB₁₂ modified electrode and its electrochemical characteristics were studied.The results showed that the VB₁₂ after electroactivated is able to electopolymerize on the GC by cyclic voltammetry(CV)in the DMSO solution.Differential pulse voltmmetry(DPV)showed that the VB₁₂ catalyzed the oxidation of NO₂^-,SO₃^2-and NH₂NH₂.The catalytic peak for NO₂^-on the modified electrode was observed at 0.76V(vs.SCE),but on the unmodified GC which at 1.0V.The catalytic currents increased linearly with the concentration of NO₂^-from 1.6×10^-6 to 4.3×10^-4 mol·L^-1 with a correlation coefficient …

Determination Of Ddopamine And Ascorbate On Gold Nanoparticle And 4,4-Bis (Methanethiol) Biphenyl (Mtp) Self-Assembled Monolayer Modified Gold Electrode, Hai-Yan Wang, Peng Liu, Ye Wang, Bao-Kang Jin

Journal of Electrochemistry

A new approach to construct an ampermetric biosensor was described.The 4,4-bis(methanethiol)biphenyl(MTP)is adsorbed on to a bare gold electrode to make self-assembled monolayers(MTP/Au SAMs).Then electrodeposited 2mg/mL HAuCl₄ at-200 mV,NG/MTP/Au electrode was prepared.When a differential pulse voltammetric(DPV)technique was used,the peak separation between DA and AA is 155 mV.Hence,the selective determination of dopamine(DA)and ascorbate(AA)in the binary mixture system can be performed.Under the chosen conditions,the peak currents are correspondent linearly to the concentrations of DA and AA in the range of 5.0×10^-7~1×10^-4 mol·L^-1 and 3.5×10^-6~1.0×10^-3mol·L^-1,respectively.The correlation coefficients were 0.998.The detection limit were 1.5×10 …

Corrosion Electrochemical Behavior Of Aluminum Flake Pigmented Water-Borne Epoxy Coating On Carbon Steel In Nacl Solution, Li-Li Xue, Li-Kun Xu, Qing-Fen Li, Hong-Qing Song, Wen-Juan Zhou, Guang-Zhang Chen

Journal of Electrochemistry

The corrosion electrochemical behavior of a water-borne epoxy coating pigmented with aluminum flake on carbon steel with artificial scratch defect was studied in 3.5% NaCl solution using electrochemical impedance spectroscopy(EIS)and scanning vibrating electrode technique(SVET).The results indicated that the defect presented anodic electroactivity at the initial stage of immersion,which extended gradually with time from the scratch into the neighboring coating,lowering the coating impedance.With further immersion,however,the electroactivity of the coating/steel interface decreased significantly due to the self-repairing of the corrosion products,causing an obvious increase of the coating impedance.In the later period of immersion,more scattered electroactive areas appeared under the coating because of …

Template Synthesis And Electrochemical Studies Of Ag(Core)Au(Shell) Nanowires, Li Ling, Ya-Xian Yuan, Min-Min Xu, Jian-Lin Yao, Ren-Ao Gu

Journal of Electrochemistry

Agcore Aushell nanowires with different thicknesses were prepared by combining template synthesis and chemical reduction method,and characterized by SEM and cyclic voltammetry(CV).The CV results revealed that the AgcoreAushell nanowires with pinhole were transferred to pinhole free structure after several potential scans.By using thiophenol(TP)and p-aminothiophenol(PATP)as probe,the surface enhanced Raman scattering(SERS)effect was investigated on the core-shell nanowires.The results indicated that AgcoreAushell nanowires could be served as a potential SERS substrate,and the difference in the spectral feature of PATP adsorbed onto Au and Ag nanowires enable us to diagnose the pinhole effect of core-shell nanowires by SERS.

Electricity Generation From A Microbial Fuel Cell Employing Desulfovibrio Salexigens, Ping Ding, Hai-Bo Shao, Guang-Zhou Liu, Dong-Xia Duan, Ting Ma, Si-Jun Chen, Jian-Ming Wang, Jian-Qing Zhang

Journal of Electrochemistry

A microbial fuel cell of laboratory scale employing Desulfovibrio salexigens in lactate based seawater substrate was proposed.Electricity was continuously harvested after inoculation.During 20 days of fermentation/discharge,COD values of the substrate decreased by 61.7%,in which 9.81% was converted to electricity.

The Research Of Several Electrodes For Spe Water Electrolysis, Jian-Bo Meng, Ge Sang, Yan Xue, Wei Cao, Xiao-Qiu Ye

Journal of Electrochemistry

Performances of the IrRu/Nafion 117/PbAg,IrRu/Nafion 117/Ni,IrRu/Nafion 117/TiNi,Ag/Nafion 117/Ni and C/Nafion 117/PtRu for the SPE water electrolysis have been investigated.The order of the electrocatalysis activity for the anodic electrodes as mentioned above is IrRu>Ag>C,and that of cathodic electrode is Ni>PbAg>TiNi.While the stability of TiNi was much better than Ni,and that of PbAg is best.Moreover,the current efficiency was raised with the increase of current density.

Study On The Contribution Of Cobalt Additives To Foam Nickel Electrodes, Xiao-Feng Li, Tong-Chi Xia, Shao-Peng Yi, Xiu-Juan Gu, Yu-Lin Song

Journal of Electrochemistry

Two incorporation ways of the cobalt additives into foam nickel electrodes,i.e.the co-precipitated and admixed method are used.The results of X-ray diffraction(XRD),cyclic voltammetry,electrochemical impedance spectrum(EIS)and galvanostatic charge-discharge curves show that(Ⅰ)there is a decrease in intensity and increase in half peak breadths of the diffraction peaks of Ni(OH)₂ with co-precipitated cobalt additive;(Ⅱ)the electrochemical activity of nickel hydroxide can be improved by both incorporation ways and the effect of admixed CoO is more notable;(Ⅲ)β-CoOOH derived from admixed CoO is not stable at lower potential,thus results in an irreversible capacity loss of nickel-metal-hydride(Ni-MH)battery after imposed overdischarged-state storage.

Determination Of Tetracyclines Based On The Flow-Through Electrochemical Detection Cell With Nickel Electrode, Dan-Mei Pan, Rong-Zong Hu, Dong-Ping Wei, Hao-Dong Ding

Journal of Electrochemistry

The electrochemical responses to tetracycline at the nickel electrode in alkaline solution were compared with that of gold and glassy carbon electrode by voltammetry.The electrocatalytic oxidation characteristics of tetracycline at nickel electrode were discussed.Subsequently a flow-through amperometric detection cell with nickel as the working electrode was designed to detect tetracycline,oxytetracycline,and doxycycline.Standard calibration graphs for the tetracyclines yielded linear ranges of 0.1~15 mg/L.Detection limits(S/N=3)of 35,45 and 43 μg/L were obtained for tetracycline,oxytetracycline and doxycycline,respectively.The system was applied for the determination of the three antibiotics in single-component drug formulations.

Study On The Electrogeneration And Properties Of Superoxide Ion In Aprotic Media By Using Carbon Nanotubes Powder Microelectrode, Ying-Liang Wei, Chen Shao, Hui Feng

Journal of Electrochemistry

Multi-wall carbon nanotubes are filled in the cavity at the tip of a microelectrode to form a carbon nanotubes powder microelectrode(CNTs-PME).The CNTs-PME is used to study the electrochemical reduction of oxygen in aprotic media.It is a nearly reversible redox process of the O₂/O₂^- couple at the CNTs-PME in the dimethyl sulfoxide(DMSO)solution.The heterogeneous electron transfer rate constant(ks)can be measured by steady-state voltammogram and the result is 9.8 10^-3cm /s.As a weak oxidant,the reaction of O₂^- with epinephrine was studied by cyclic voltammetry.Additionally,the reaction of O₂^- with benzoic acid was also discussed …

Square Wave Stripping Voltammetric Behaviors Of Actinomycin D On Glod Electrode And Its Application, Qing-Tao Zhu, Fang Liao, Xiao-Ying He

Journal of Electrochemistry

The electrochemical behaviors of Actinomycin D(ACTD)at glod electrode were investigated by square wave stripping voltammeter in the KH₂PO₄-Na₂HPO₄ buffer solution(pH=5.90).The sensitive oxidation peak of ACTD was observed and the potential peak for ACTD is-0.17 V(vs.SCE).The Experimental parameters,such as pH value,amplitude,accumulation potential and time were optimized,and a direct electroanalytical method for determining ACTD was developed.The peak currents were proportional to the concentration of ACTD in the range of 0.1μmol·L^-1～10.0μmol·L^-1,and the linear regression coefficient equaled 0.9991.The detection limit for ACTD was 1.0×10^-8mol·L^-1.

Voltammetric Behavior And Electrocatalytic Properties Of Hemoglobin At Glassy Carbon Electrode Modified With Lauric Acid, Xin-Rui Miao, Xu-Hong Zhang, Ying Xie

Journal of Electrochemistry

The electrochemical behavior of hemoglobin at glassy carbon(GC)electrode modified with Lauric Acid was studied.In the potential of +0.6～-0.7 V(vs.Ag/AgCl),an irreversible cathodic peak was observed at-0.3 V at the scan rate of 20 mV·s^-1.In the medium of 0.02 mol·L^-1 KH₂PO₄-Na₂HPO₄(pH 7.0),ip increased with the increasing concentration of Hb and the value of pH.The peak currents were proportional to the concentrations of hemoglobin in the range of 1.00×10^-8～5.00×10^-9 mol·L^-1 and 1.92×10^-6～2.06×10^-7 mol·L^-1.The data was analyzed in details by simulating in order to …

Modification Of Electrolytic Manganese Dioxide, Shu-Rong Ding, Xin-Hai Li, Zhi-Xing Wang, Hua-Jun Guo

Journal of Electrochemistry

The EMD samples coated with CMD-Bi compound were prepared by liquid-phase surface treatment method.XRD and SEM research indicated that the modified manganese dioxide, i.e, EMD/CMD-Bi, could keep γ-MnO₂ crystal structure of EMD and had more pores on its surface with an obvious floccule layer.Electrochemical test indicated that the second electron reduction peak current increased by 1.5 times and the discharge capacity increased by 40.8% and 78.3% respectively than that of pure EMD electrode under the condition of-0.8 V(vs.Hg/HgO) cut-off voltage at 30.8 mA/g and 102.7 mA/g current density.

Electrochemical Performance Of Li(1-X)MXFepo4 Cathode Materials Synthesized By Polymer Pyrolysis Route, Ting Li, Jiang-Feng Qian, Yu-Liang Cao, Han-Xi Yang, Xin-Ping Ai

Journal of Electrochemistry

Olivine Li_1-xM_xFePO₄(M=Cr³⁺, Mg²⁺, Mn²⁺, Ni²⁺) were synthesized by a polyacrylates-pyrolysis route. The structural and electrochemical properties of the as-synthesized cathode materials were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical charge/discharge cycling. The results indicate that the metallic ions doped at low concentration do not affect the crystalline structure of the material, but considerably improve the rate capability and cycle performance of LiFePO₄ at high rate.

Design And Development Of An In-House Scanning Tunneling Microscope System, Esvar Subramanian

All Theses

ABSTRACT
The invention of Scanning Tunneling Microscope (STM) by Binnig and Rohrer in 1982 eliminated the use of optical lenses and replaced the conventional optical microscopes with a new class of microscopes called the Scanning Probe Microscopes (SPM). Because of their unique characteristics such as higher resolution and acquisition of nano level images without affecting the physical properties of the sample, they have found wide applications in a variety of scientific disciplines such as biology, material science and electrochemistry. After considerable advancements in instrumentation, the STM has evolved as a nanomanipulation and nanofabrication tool. It operates in two modes: constant …