Engineering Science and Materials Commons^™

Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna

Tanzania Journal of Engineering and Technology (TJET)

Vibration is one of the techniques employed in the determination of dynamic properties of fruits and vegetables. It entails generation of a mechanical or acoustic vibrational signal which is propagated through the flesh of the agricultural material. A transducer is either attached or held close to the specimen to monitor the propagation of the signal through the specimen. The manner in which the signal is transmitted through the material is analyzed, and the dynamic properties of the specimen which relate to its firmness or its internal being are derived. The technique has been around for the past 30 years or …

The Electrochemical Behaviors Of Superoxide Dismutase At Promoter Modified Gold Electrode, Xia-Qin Wu, Xiao-Yun Meng, Zhe-Su Wang, Zong-Rang Zhang

Journal of Electrochemistry

The electron-transfer process of superoxide dismutase was investigated by cyclic voltammetry at the 4,4'-dithiodipyridine, L-cysteine, histidine and arginine modified gold wire electrodes repectively. The quasi-reversible behavior was observed at L-cysteine modified gold electrode. An irreversible electrochemical behavior has been observed at hisdinine modified gold wire electrode.

Electro-Oxidation Of Phenol On Sno2/Ti Electrodes Prepared By Thermal Oxidation, Qing-Song Zhang, Hui-Huang Wu

Journal of Electrochemistry

A SnO₂/Ti electrode prepared by thermal oxidation was used as the anode for galvanostatic electrolysis in acidic solution containing phenol, the time-dependances of phenol concentration, chemical oxygen demand in solution(COD) and instantaneous current efficiency were determined during electrolysis. The results show that with the SnO₂/Ti anode instead of Pt, the COD significantly decreases at the same charge passage, and average current efficiency of oxidation increases by three times. The mechanism for phenol oxidation at two electrodes was discussed.

The Studies Of The (Photo) Electrochemical Character On The Electrodeposited Silver Indium Selenium Thin Films, Shao-Ai Xie, Xun-Nan Deng, You-Jin Kua

Journal of Electrochemistry

A photoelectrochemical cell (PEC) is constructed, using an AgInSe₂ film photoanode made from electrodeposition and a platinium electrode in aqueous polyiodide or polysufide electrolyte. The V_oc and I_sc of PEC have been tested and measured, and the effect of chemical decoration on the photoanodes also studied.

Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guang-Qiang Li, Zhitong Sui

Journal of Electrochemistry

In fuel cells, the structure of electrodes is an important factor which effect the cell performance. To improve the structure and the performance of electrodes, a new method of providing fuel cell electrodes is proposed in this paper. PTFE (polytetrafluoroethylene) and ethyne black was ground for about half an hour in a high-speed grinder, then the catalyst was added into the grinder and milled for an hour. This milled catalyst was transferred into a mixer followed by the addition of surface-active agent. After a suspension was formed, it was filtered under vacuum condition.Then a thin uniform filter-cake of the catalyst …

Study On Electrochemical Reduction Properties Of Nitrobenzene, Chu-Na Ma, Wen-Kui Zhang, Hui Huang, Yong-Ping Gan

Journal of Electrochemistry

The electrochemical reduction characteristics of nitrobenzene was extensively investigated by using the techniques such as quasi-steady-state polarization, cyclic voltammetry, fast linear potential sweep method and chronoamperometry in this paper. The electroanalytic properties of Cu, Cu-Hg and Cu-Ni electrodes were evaluated. Based on the study of the transient steping behaviour of nitrobenzene to PAP, the reduction mechanism was discussed. The results showed that the transition steps existed on the electrochemical reduction of nitrobenzene in acidic solution, the reactant is also absorbed on electrodes surface. The control step in the reduction of nitrobenzene was ascribed to the diffusion of nitrobenzene and its …

A Novel Reaction Region Moving Electrode System For Electrochemical Power Sources, Jin-Kua You, Que Tu, Zheng-Jian Wang, Jie Sun, Zu-Geng Lin

Journal of Electrochemistry

In most of practical rechargeable batteries, charging/discharging process is always concerned with phase-transformation in the solid state. Due to the irreversibility of the phase-transformation, the cyclic performance of the rechargeable batteries are limited. In this paper, a novel reaction-region moving counter electrode system is constructed in our laboratory. The electrode system is operated at room temperature and cycled in solid-liquid phase during charging/discharging processes. With this electrode, the metal-complexes are firstly deposited (i.e. charging process) on the nearest working electrode and gradually extended to those another working electrodes several centimeters away from the counter electrode. The deposite is dissolved again …

High Performance Proton Exchange Membrane Fuel Cells, Jing-Rong Yu, Bao-Lian Yi, Ming Han, Xiao-Liang Cheng, Zhi-Gang Shao, Jing-Xin Zhang

Journal of Electrochemistry

Proton-exchange membrane fuel cells(PEMFC) using a perfluorosulfonic acid proton exchange membrane as an electrolyte can simplify water and electrolyte management. In this paper, the effects of thickness of PEM on the performance of PEMFC were studied. The Nafion-112 PEM and low platinum loading E-TEK electrode yielded very high power density, of the order of 0.95 W/cm². The energy-conversion efficiency, the degree of platinum utilization and stability for PEMFC using Nafion 112 and E-TEK electrode were also investigated.

Photoelectrochemical Studies On The Tio2 Nanostructured Porous Film Sensitized By Cyanine Dye, Li Zhang, Mai-Zhi Yang, Xue-Bin Qiao, Yan-Zhong Hao, En-Qing Gao, Sheng-Min Cai

Journal of Electrochemistry

The photoelectrochemical behaviors of the TiO₂ nanostructured porous film sensitized by cyanine dye were investigated in this paper. The results showed that the excitaed state level matched the conduction band edge of TiO₂ nanoparticle. Therefore the sensitization of the dye can increase the photocurrent intensity of the TiO₂ nanostructured electrode obviously and results in a red-shift of optical absorption from the ultra-violet region to the visible. As a result, the light-to-electricity conversion efficiency was improved evidently, the maximum value of IPCE has reached 12.1%.

Investigation Of Sodium Hypophosphite Anodic Oxidizing Behavior In The Process Of Acid Electroless Nickel Deposition, Mei-Yuan Wang, Ya-Fei Kuang, Yan Xu

Journal of Electrochemistry

The anodic oxidizing behavior of sodium hypophosphite in the process of electroless nickle deposition (pH=5.5) was investigated with the linear potential sweep method and alternating current impedance. The results indicated that, the oxidation of NaH₂PO₂ was a complicated electrochemical process and affected by the concentration of NaH₂PO₂, the temperature of the bath, the sweep rate and the existence of nickel ion. The NaH₂PO₂ electrooxidation reaction was very likely preceded by heterogeneous interface transformation process, which might be the control step of the whole anodic process.

The Preparation Of Flexible Polymeric Anode And The Measurement Of Its Protective Ability For Cathodic Protection, Ai-Ling Du, He-Ming Zhang, Ming-Zong Zhang, Shi-De Ma

Journal of Electrochemistry

The flexible electrode, whose shape can be changed freely, was made of ethenyl copolymer and conductive component and proper amount of additive for cathodic protection. The resistance of electrode was measured.In low concentration of H₂SO₄, the flexible electrode can be used as auxiliary anode to protect the carbon steel. The protection ability of the flexible auxiliary anode was measured too.

Studies Of The Electrode Preparation Of Electrode From Lead Carbonate For Lead Acid Batteryⅰ. The Activation Of The Pme, Zhong-Xu Dai, Di-Hua Wang, Jun-Wei Jiang, Yun-Hong Zhou, Jin-Yun Zou

Journal of Electrochemistry

Lead carbonate which was an intermediate product in lead hydrometallurgy without pollution of lead vapor and sulfur dioxide was selected as electrode material of lead-acid batteries. In the present work, the performances of PbO₂/PbSO₄ or PbSO₄/Pb electrode transformed from PbCO₃ have been investigated by powder microelectrode technique combined with cyclic voltammetry. The results show that the CV characteristics of either negative or positive electrode prepared from PbCO₃ is as good as that of both electrodes made from lead oxide produced by mill machine,when a powder microelectrode with PbCO₃ transformed into PbSO 4 …

Breakaway Steel Guardrail Post, Dean L. Sicking, John D. Reid, John R. Rohde

Department of Mechanical and Materials Engineering: Faculty Publications

A breakaway guardrail post includes upper and lower post sections spaced apart but connected by a breakaway joint. The joint is attached at one end to the upper post by a first fastener set and connected at a second end by a second fasteners set. Upon impact forces being applied to the upper post section, the first fastener fails and the upper post section rotates downwardly.

A New Method For Preparing Self-Assembled Lipid Bilayers On Pt Electrode, Peng Diao, Dian-Lu Jiang, Xiao-Li Cui, Deng-Ping Gu, Ru-Ting Tong

Journal of Electrochemistry

A new method for preparing Pt-supported bilayer lipid membrane (Pt-BLM) on Pt electrode cleaned by high power ultrasound was reported. The reported method was convenient, costing less platinum and could be used to form large-area Pt-BLM as compared with the traditional Pt-wire-cutting method. The electrical properties of Pt-BLM were studied using electrochemical impedance spectroscopy and cyclic voltammetry. Experimental results showed that the values of membrane capacitance and the voltammetric characteristics were consistent with those of Pt-BLM prepared by traditional method.

Direct Electrolysis Of Seawater On Conducting Film For Microbial Anticorrosion 1. Simulation And Measurement Technique, Wei-Ling Hu, Ling-Ling Wu, Jing Zhou, Jing-Xin Li, Jin Luo, Zhong-Hua Lin

Journal of Electrochemistry

Based on the electrochemical micro probe and the weak signal detection technique, simulated test and measurement system were set up by the use of four-electrode cell(including a micro electrode), bipotentiostat, lock-in amplifier and three-dimensional micro manipulating device. Based on the system, the micrometer scale concentration distribution of trace hypochlorite, which is produced by direct electrolysis of seawater on the conducting film for preventing microbial corrosion has been obtained for the first time. Both relationships between concentration of hypochlorite and its reduction current, which is termed an working curve, and between the reduction current of hypochlorite and measured time are reported.

A Study Of The Corrosion On Bronze, Hong-Fan Zhu, Hao Zhou

Journal of Electrochemistry

The bronze is the treasure in chinese metallic antique, which was typified by product in Shang-Zhou period (three thousands years ago). Because of corrosion, archaeological messages, such as inscription and pattern on the surface of bronze, would be damaged then the value of bronze antique decreased. The bronze disease is a common disease which forms powdery rust on the surface of bronze in atmospheric environment, the powdery rust emerge from under incrusted rust, then spreads, and eventually leads to bronze damaged. This paper investigates the bronze disease. According to the chemical and electrochemical tests in simulated occluded cell, the variation …

Electrochemical Synthesis Of Fes Electrode And Its Behavior Measurement, Cong-Sheng Guan

Journal of Electrochemistry

The Potential for the electrochemical synthesis of FeS electrode has been obtained by cyclic voltammetry. FeS electrodes were synthesiaed by controlling Fe electrode at -1.0 V in LiCl-KCl-Li₂S and Li(FClI)-Li₂S melts and their behavior were measured also. The FeS electrode synthesized in molten Li(FClI)-Li₂S has the best charge and discharge properties.

Deactivation Of Nickel Oxide/Hydroxide To Electrooxidation Of H2Po2 Anions On Nickel Electrodes In Alkaline Solutions, Tai-Xiang Jiang, Hui-Huang Wu

Journal of Electrochemistry

Electrooxidation of hypophosphite anions on polycrystalline nickel in alkaline solutions has been investigated by cyclic voltammetry and open circuit potential measurements. The results are explained based on the mechanism that the first step of hypophosphite oxidation is the adsorption of hypophosphite ions on nickel, followed by the homolysis of its hydrogen bond with the formation of radicals. The oxidation of hypophosphite on nickel in alkaline medium occurs at lower potentials between ca. -0.8 V— -1.1 V (SCE) and phosphite ion is the only oxidation product. There is no indication of hypophosphite oxidation at higher potentials. Severe deactivation of the surface …

Structural And Electrochemical Studies On Lithium Manganese Oxide Containing Li+ Prepared By Hydrothermal Method For Lithium Ion Batteries, De-Yao Liu, Jin-Kua You, Wei Chu, Yong Yang, Zu-Geng Lin

Journal of Electrochemistry

In this paper, Todorokite manganese oxides containing Li⁺ with large tunnel structure (sample M5) have been synthesized by hydrothermal methods from natural manganese oxide nano fiber (sample M4). The structure and composition of the samples were characterized and analyzed by XRD, ICP, TGA and DTA. Its electrochemical behavior as a cathode materials for rechargeable lithium ion insertion were studied by galvanostatic charge/discharge measurements. XRD results show that the sample M4 is mainly composed of Birnessite and Vernadite structure. Although the sample M4 shows a high initial capacity of approximately 150 mAh/g, its performances decrease gradually over 30 cycles. It …

The Techniques Of The Paired Electrosynthesis, Hong-Kun Zhang, Deng-Ping Gu

Journal of Electrochemistry

In this Paper, we introduce our work on paired electrosynthesis. In conjunction with our research practice, we introduce electrolytic conditions,such as material of electrode ,courrent density and electrolytic temperature etc,as reference for researcher. We categorize the paired electrosynthesis techniques to widen our view on the paired electroorganic synthesis and to promote the deveopments of paired electrosynthesis techniques.

Influence Of Thiourea And Its Derivate On The Process Of Cathodic Electrodeposition Of Copper, Yun-Hui Dong, Ai-Hong Zou, Yun-Xia Zhao

Journal of Electrochemistry

The effects of thiourea and its derivate on the electrodeposition of copper from the dilute acid sulphate solutions have been studied by using potential sweep techniques at quasisteady state. Limiting current densities (I_d), exchange current densities (i₀) and α_n are obtained by data processing with the least square method. Thiourea has a depolarizing effect on the copper depositing at concentrations below 8 mg·L^-1, and a polarizing effect at higher concentration (>10 mg·L^-1), and it changes the mechanism of copper deposition reaction. Propenyltiourea and Phenylthiourea have a depolarizing effect on the …

Study On Synthesizing Of 2-Methylbutanoic Acid By Indirect Electrooxidation, Chong-Tao Zhao, Ze-Shan Zhu

Journal of Electrochemistry

The working conditions of synthesizing 2-methylbutanoic acid by oxidizing 2-methyl-1-butanol with tetrabutylammonium hydrosulfate (TBAS) or tetrabutylammonium perchlorate (TBAP) as phase transfer catalyst in sulfuric acid Cr(Ⅵ) oxidation medium was studied. The Cr(Ⅵ) oxidation medium could be electrolytic regenerated from Cr(Ⅲ), during above oxidation reaction. Under the optinum condition, the yield of 2-methylbutanoic acid is more than 95%.

The Ac-Impedance Analysis For Pluse Oxide Film Of Aluminium Alloy, Ai-Ling Du, Xi-Cheng Ma, He-Ming Zhang

Journal of Electrochemistry

Bode diagrams for aluminum PC (abbreviated from pulse current) oxide films were first obtained by AC-impedance measurements in a wide range of frequency. The experimental results show that different kinds of electrical equivalent circuits can be used for representing PC films and DC (abbreviated from direct current) oxide films separately, the main differences between them are their porous layers, the PC films are more even with little defects.Those are also verified by SEM and V-I characteristic curve measurements.

Calculation Of Corrosion Rate Of Passive Metals With Charge Curve Analysis Technique, Yuan-Sheng Zhang, Min Gong

Journal of Electrochemistry

This work contains two parts: (1) A charge curve equation having no appro-ximation for passivated metal corrosion systems is derived and compared with the routine charge curve equation, which is virtual only when the polarization is minim(linear range). (2) It is simpler to analyze charge curve data by from of charge differential equation than from charge curve equation. After the charge curve data are measured, the slope of charge curve is computed by numerical differentiation method, then the charge differential equation may be transformed to a set of linear equations using polynomial approximation. The electrochemical parameters of corrosion system would …

The Effects Of Metallic Cobalt Abbition On The Performance Of Pasted Nickel Electrodes, An-Bao Yuan, Jian-Qing Zhang, Wan-Chun Ding, Shao-An Cheng, Chu-Nan Cao

Journal of Electrochemistry

The Ni-foam pasted nickel electrodes prepared by coprecipitated Ni_1-XZn_X(OH)₂ with and without cobalt power addition have been studied. The electrode with addition of metallic cobalt showed a higher performance both in discharge capacity and cycle life. It is known from the experiment results that the addition of Co can remarkably increase the active material utilization which is suggested to be improvement of discharge depth due to the conducting CoOOH formed in the first activation charging. The superior capacity during cycling could be attributed to the synergistic action of zinc and cobalt addition ,especially to the …

Foundation Sleeve For A Guardrail System, Dean L. Sicking, John D. Reid, John R. Rohde

Department of Mechanical and Materials Engineering: Faculty Publications

A highway guardrail terminal system having horizontally extending guardrail elements mounted on a plurality of posts. Foundation sleeves having an elongated slit along one side retain and support appropriate guardrail posts. A plurality of stiffing ribs extend across the slit at a distal portion of the tube. The sleeves enable a safer and faster removal of broken guardrail posts after vehicular impact.

Large Amplitude Pitching Of Supermaneuver Delta Wings Including Flow Control, Yahia A. Abdelhamid

Mechanical & Aerospace Engineering Theses & Dissertations

The unsteady, three-dimensional Navier-Stokes equations are solved to simulate and study the aerodynamic response of a delta wing undergoing large amplitude pitching motion up to 90° angle of attack. The primary model under consideration consists of a 76° swept, sharp-edged delta wing of zero thickness, initially at zero angle of attack. The freestream Mach number and Reynolds number are 0.3 and 0.45 × 106, respectively. The governing equations are solved time-accurately using the implicit, upwind, Roe flux-difference splitting, finite-volume scheme. Both laminar and turbulent flow solutions are investigated. In the laminar flow solutions, validation of the computational results is carried …

Effect Of Temperature On Short-Term Creep Rupture Response In Polymer Matrix Pultruded Composites, Robert Harold Munson

Mechanical & Aerospace Engineering Theses & Dissertations

Polymer matrix pultruded composites have increasingly been used in applications where high strength-to-weight ratio and corrosion resistance are needed. Bridge and pier components are a couple of recent applications due the composite's resistance to corrosion from salt water. In applications of this sort, the material will commonly be subjected to sizable static loads while exposed to varying weather conditions. In using pultruded composites for these applications safely, a better understanding of the material's response to ambient conditions is necessary.

In this thesis, rectangular specimens of a polyester matrix glass reinforced pultruded composite sheet are subjected to both static tensile loading …

Adaptive Sampling For Coordinate Metrology, Robert Edgeworth, Robert G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

An iterative sampling process for dimensional measurement is presented. The strategy is based upon the use of surface normal measurement data to develop an interpolating curve between sample points. The interpolant is used to select subsequent measurement targets iteratively. The process is repeated until the measurement converges to a complete and accurate evaluation of the surface. The required sample size is proportional to part quality. The most accurate parts will require the least sample points; whereas, lower quality parts will require a greater number of total samples. The method is particularly applicable to measurement of complex surfaces with coordinate measuring …

Newton Parameter Update Algorithm For Recurrent Neural Networks Applied To Adaptive System Identification And Control, Donald Allen Gates

Electrical & Computer Engineering Theses & Dissertations

This paper shows that the combination of a second-order neural network parameter update algorithm and internal network feedback can be effectively used for adaptive, nonlinear, dynamical system identification and control. Adaptive neural identification and control algorithms are typically utilized for real-time applications where the rate of adaptation is often critical. A fast, adaptive network parameter update algorithm is presented.

Simulation results show that this algorithm is capable of quickly identifying and adapting to changes in system parameters, making it feasible to use for real-time control and fault accommodation applications.