Engineering Commons^™

Protection Of Steel Using Aluminum Sacrificial Anodes In Artificial Seawater, Tai-Ming Tsai

Journal of Marine Science and Technology–Taiwan

The performance of aluminum alloys used as sacrificial anodes for cathodic protection in seawater was investigated in this study, Results show that A1 -3.5%Zn -0.05%In sacrificial anode alloy C has the best current efficiency, most negative open circuit potential and energy characteristics among five different Al-Zn-In alloys. Polarization curve of alloy C also shows no passivation behavior in artificial seawater. The corrosion rate of mild steel in artificial seawater was determined as a function of applied cathodic potential. The cathodic protection potential determined for mild steel in seawater was -0.78 V,SCE for a corrosion rate of less than 1 mpy. …

Manipulation Of Transfer Function Matrix Via State-Space Approach, Jeng Yih Juang

Journal of Marine Science and Technology–Taiwan

Algebraic manipulations of transfer function matrix via statespace approach will be given without referring to the symbolic manipulations involving the indeterminate s, for a linear continu-ous-time system (or, z, for a linear discrete-time system). The resultant transfer function is closely related to a state-space representation, and therefore is advantageous in realization, implementation, computer simulation and stability analysis. Furthermore, the design, implementation, and analysis of linear dynamic controllers, in the forms of 2-input-1-output and 2D (two degree of freedoms), are illustrated with numerical examples via the method proposed.

Nondestructive Testing Of The Corrosive Damage Of Reinforced Concrete Structures Using Ultrasonic Method, Ming-Te Liang, Run Huang, Chii-Ming Jiang

Journal of Marine Science and Technology–Taiwan

The purpose of this study is to determine the corrosive damage of reinforced concrete members using the ultrasonic technique. The ultrasonic tester (type ULCON 3) connected the touched vertical-beam dictator (frequency: 50kHz, diameter=20mm) is used to measure the velocity and scan the concrete surface for predicting the corrosive damage, When the rebars are corroded, the ultrasonic wave propagation will very due to energy decay and velocity change. Based on the ultrasonic pulse velocity and amplitude, the structural quality of reinforced concrete can be predicted. Some results obtained from this investigation are described as follows: (1) 'The amplitude of refective wave …

Network-Integrated Ship Automatic System And Internetworking To The Internet, Li-Der Chou, Jeng Yih Juang

Journal of Marine Science and Technology–Taiwan

Many automatic systems developed for the merchant ships are focused on the Unmanned Machinery Space (UMS), and therefore it is necessary to build a local area network (LAN) on the ship in order to integrate these automatic systems. By means of the Inmarsat satellite system, the shipboard LAN is interconnected with the terrestrial communication networks such as the Internet. In the paper, the shipboard LAN is designed from the view point of survivability, and three concepts to reduce the satellite communication cost for the interconnection of the shipboard LAN and the Internet are proposed. Finally, the way to implement the …

Elastic Modulus Of Concrete Affected By Elastic Moduli Of Mortar And Artificial Aggregate, Chung-Chia Yang, Yon-Yer Lin, Ran Huang

Journal of Marine Science and Technology–Taiwan

The effect of two artificial aggregate types and three kinds of mortar on the elastic modulus of concrete are reported. Bighteen batches of concrete with various volume fractions (10%, 20%, and 30%) were selected. Theoretical moduli were calculated based on micromechanics. Following recent studies of concrete as a twophase composite material, this study examines whether there is a relation between the elastic modulus of the constituents and concrete. From the examination of available experimental results, it is apparent that elastic modulus of concrete is affected by elastic modulus of constituents and volume fraction of aggregate. Test results were compared with …

A Study On Fabrication Of Zinc Oxide Thin Film Acoustic Sensors, C.C. Chang, J.H. Chang

Journal of Marine Science and Technology–Taiwan

In this study, acoustic sensors were formed by depositing a zinc oxide (ZnO) thin film on a silicon dioxide/silicon(SiO/Si) substrate using radio frequency (RF) planar-magnetron sputtering method. The results showed higher substrate temperatures and higher RF powers enhanced C-axis oriented structure of the Zno thin film and optimized the ZnO thin film acoustic property. The frequency spectrum measurement on the acoustic sensor underwater involved three peaks at frequencies 640 KHz, 2.4 MHz and 2.9 MHz, respectively. Sensitivity reached to -132.02 dBrelv/ upa. The results indicated that under the pressure of acoustic frequencies the sensor response was directly proportional to pressure …

Top Gear Manufacturing, B Mahadevan

IIMB Management Review

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

Corosion Potential Imagingat The Interface Of Coating/Metal By A New Electrochemical Technique, Changjian Lin, Xiangdong Zhuo, Jidong Chen, Hui Wang, Rong-Zong Hu, Yi Song, Jian-Guang Tan

Journal of Electrochemistry

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Problems On The Study Of Anodic Films On Pb In Sulfuric Acid Solution (Ⅱ), Houtian Liu, Qunzhou Wang, Yongqin Wan, Weifang Zhou

Journal of Electrochemistry

The conditions for the growth of the different phases in the anodic Pb(Ⅱ) film on Pb in sulfuric acid solution were discussed.

Status Of The Research And Development For Fuel Cell Technology Abroad, Naichao Li, Baolian Yi

Journal of Electrochemistry

Status of the research and development for fuel cell technology abroad was overviewed, and at the aim of accelerating the research and development for fuel cell technology in China, the corresponding stategy for our country was recommended.

In Situ Studies Of Copper Electrodepostion On Hopg By Using Ecstm, Zhaoxiong Xie, Bingwei Mao, Xiangdong Zhuo, Jiqian Mu, Zhaowu Tian

Journal of Electrochemistry

In this paper, copper electrodepostion on HOPG had been in situ studied by using a homebuilt electrochemical scanning tunneling microscopy (ECSTM). Three dimensional nucleation and subsequent growth of copper crystals were found as the initial stage of copper deposition on HOPG. In the case of lower overpotential or lower concentration of Cu²⁺ , the bulk deposited copper layer tended to form smooth terraces, and grow at the edge of steps. The terraces were stable to some extent, which made it possible to be observed with atomic resolution. At a higher overpotential, the crystal size of copper were somehow smaller. …

A Study Of The Electroplated Fe-Cr-Ni Alloy Microstructure, Donglin Li, Jianping Liu, Fangzhou Guo, Jianrong Hua

Journal of Electrochemistry

The microstructure of the electroplated Fe-Cr-Ni alloys from the mixed carboxylic acid solution containing Cr(Ⅲ) and additives were determined with XRD and SEM. Experimental results showed that, under the experimental condition, the phase component, structure of Cu base electroplated Fe-Cr-Ni alloys had a critical thickness, which was 11 μm and a critical Ni content, which was 32%. Organic additives, formic acid or polyethylene Glycol, mainly affected the surface, cross section morphology of the electroplated Fe-Cr-Ni alloys. Adding Mo to the electroplated Fe-Cr-Ni alloys led to remarkable corrosion resistance in concentrated HCl.

The Applications Of Poap Ni2+ Films Modified Electrode As Sensor For Alcohol, Bingzeng Hua, Wenyun Hu, Yanzhen Chen

Journal of Electrochemistry

POAP Ni²⁺ films modified electrode can electrocatalyzes significantly the oxidation of alcohol. The modified electrode can be used as the electrochemical sensor for the detection of alcohol. But the oxidation of alcohol is effected by the thickness of films、the concentration of nickel ion in films, pH of electrolyte, as well as temperative. All of those conditions have been studied in order to achieve stable response current during the oxidation of alcohol, and the relation between concentration and current has been made. At last the major characteristic parameters, such as the low limitation of concentration, the response time, the ability …

Surface Raman Spectra Of Pyridine And 2 Mercaptopyrimidine Adsorbed On Rough Nickel Electrode, Qunjian Huang, Jinsong Gao, Xiongwei Cai, Bingwei Mao, Mingsen Zheng, Zhongqun Tian

Journal of Electrochemistry

The Raman spectra of pyridine and 2-mercaptopyrimidine (2-MP) adsorbed on bare nickel electrodes roughened by a HNO₃ etching procedure have been obtained for the first time by utilizing a highly sensitive confocal Raman microscope. Their adsorption behaviours are discussed briefly. This primary result illustrates a great potential for in-situ Raman spectroscopy in the study of chemical and electrochemical processes of transition metal surfaces.

Electrocatalytic Oxidation Of Some C2 Compounds (Alcohols, Aldehydes, And Carboxylic Acids) On A Pt/SbAd Electrod, Hong Li, Lincai Jiang, Xiong Jiang

Journal of Electrochemistry

The electrocatalytic oxidation behavior of some C₂ compounds(alcohols, aldehydes and carboxylic acids) on a Pt/Sb_ad electrode prepared in-situ or ex-situ UPD was investigated using pontential sweep and rotating disc electrode methods. It is confirmed that Pt/Sb_ad electrode show the most electrocatalytical active to the oxidation of aldehyde functional group and only a little activity to the oxidation of hydroxyl group, but no activity for the oxidation of carboxyl group.

The experimental results show that the activity of the Pt/Sb_ad electrode prepared by ex-situ UPD is higher than that prepared by in-situ UPD.

The limitations of the …

Oxygen Charge Transfer Reaction At The Pt/Ysz Interface, Yi Jiang, Wenzhao Li, Jingwang Yan, Shizhong Wang

Journal of Electrochemistry

Oxygen Charge transfer reaction has been investigated by various degrees of potential polarization at the Pt/YSZ interface. Anodic and cathodic charge transfer coefficients were found to be unity over the wide range of oxygen partial pressures and temperatures. While the exchange current density of the interface was found dependent on the partial pressure of oxygen in accordance with the relation: i₀=2FKr(K_O2P_O2)^1/4(1+K_O2P_O2)^1/2. Several important parameters, such as electrochemical rate constant, equilibrium constant of oxygen adsorption on Pt surface had also been extracted.

Studies Of Surface Treatment Methods And Their Operating Mechanisms For Activation Of Hydrogen Storage Electrode, Ronghui Hu, Hanxi Yang, Shigang Lu, Shengxian Li, Jingcheng Liu, Chongzhi Yang

Journal of Electrochemistry

Surface treatment methods by use of charge discharge cycling, KBH₄ reduction and KOH etching were parallely investigated for the rapid activation of Mn(NiCoMnAl)₅ electrode. It is found that the MH electrode treated with hot and concentrated KOH solution exhibits rapid and full activation, and also gives lower discharge overvoltage, higher stable capacity and improved cycleability. It is also revealed from SEM, EDAX and ICP analysis that the KOH activation of the electrode proceeds mainly through the enrichment of mischmetal and nickel in surface to form electrocatalytically active surface for hydrogen absorption reaction, but the surface modification with KBH …

Electrocatalytic Reduction Of Nitrite In The Presence Of Complex Of Cobalt(Ⅱ) And 1,10 Phenanthroline, Jian Tong, Xiaojun Dang, Hulin Li

Journal of Electrochemistry

The electrochemistry of cobalt(Ⅱ)-1,10-phenanthroline Co(Phen)₂²⁺ complex and its ability to electrocatalyze the reduction of nitrite were studied, we found that this complex could act as a catalyst in alkaline or neutral solution for nitrite reduction. We have investigated the effect of the complex composition on electrocatalytic ability. The effects of pH value, complex concentration, regeneration and activation of electrocatalyst on the catalytic current have been studied and discussed.

Study On Electrode Constructure And Electrical Performance Of Na/S Cell, Jianhua Yang, Jiadi Cao

Journal of Electrochemistry

A sodium wick for sodium electrode and trough shaped performs for sulfur electrode in Na/S cell were designed and investigated. The experiments suggested that the sodium wick for sodium electrode not only improved the discharge performance of cell but also reduced the quantity of sodium utilization, and increased the specific energy of Na/S cell. The trough shaped preform with alumina fibres for sulfur electrode decreased the polarization, improved the charge acceptance and prolonged the life of cell.

The Reduction Of Oxygen To Hydrogen Peroxide In An Acidic Trickle Bed Cell Using Graphite Chip Cathode, Zhaoe Lu, Guanyong Zhang, Tiangeng Zhong, Guonu Fang

Journal of Electrochemistry

The authors investigated the electrochemical reduction of oxygen to hydrogen peroxide in 0.05 mol/L H₂SO₄ solution by the trickle bed electrode using graphite chip. The bed dimension was 14×5×0.6 cm. The current efficiency and the concentration of H₂O₂ in the catholyte were determined at various current strengths and various rates of adding the electrolyte. The proper current was 0.15 A. i.e. the current density was 2.1 mA/cm² vertical cross section area of the bed. The concentration of H₂O₂ reached 7×10^-3 mol/L with the current efficiency of 0.2. If the …

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

Towards Rational Trade Offs Between Environment And Hydro-Power, V Ranganathan

IIMB Management Review

The economic importance of hydro-power has long been recognised the world over. In fact, a certain correlation between exploitation of hydropower potential and economic growth is clearly discernible. Developed nations of North America and Western Europe, for example, have exploited 83% and 98%, respectively, of their potential hydro- power, while relatively poorer East European, Asian and African countries have a much lower record, ranging between 8% and 36% (see chart). Recent trends in hydro-power development in India are a source of serious concern: for instance, the hydro-thermal ratio of power generation in the country has been steadily declining from 1:1 …

Bs News

Building Services Engineering

No abstract provided.

Electrochemical Ploymerization Of Aniline In The Alkaline Solution And Properties Of Polymer, Shaolin Mu, Jinqing Kan, Aiguang Zhang

Journal of Electrochemistry

A deep yellow polyaniline was formed at the anodic electrode during electrochemical oxidation of aniline in the alkaline solution. The peak of oxidation potential for aniline in the alkaline solution was 0.7 V (vs.Ag/AgCl with a saturated KCl solution), which is about 0.3V less than that in the acidic solution. The results from rotating ring-disk electrode experiment show that two soluble intermediates were generated during electrochemical oxidation of aniline. The colour of the polymer in the alkaline solution is independent of applied potential and pH values. An adsorption peak was observed in the UV region at 500 nm for the …

Determination Of Transport Number Of The Modified Liclo4-(Peo)20 Polymer Electrolyte, Ruqi Zhou, Qngguo Liu, Weihua Qiu, Yun Zhang, Yuee Zhao, Leiling Yang

Journal of Electrochemistry

In this work a combination method of A.C. Impedance and chronoamperometry was used to determine the lithium ion transport number of LiClO₄·(PEO)₂₀·(PC)₁₂·(EC)₁₂ polymer electrolyte. It is known that lithium is thermodynamically unstable in non-aqueous or polymer electrolytes, leading to the formtion of a film on lithium surface, called as solid electrolyte interphase (SEI). The presence of SEI layer will greatly influence the experimental result of lithium ion transport number. The new method avoid the effect of SEI layer, and can give correct transport number of lithium ion in the electrolyte of DCIO_{4 …}

Study Of Electrochemical Behaviour Of Myoglobin Using Cyclic Voltammetry And Synchronous Fluorescence Spectroscopy, Ju Chou, Haihong Zhou, Tianhong Lu, Yue Wu

Journal of Electrochemistry

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The Inhibition Of Amphipathic S- And N-Containing Compounds On Carbon Steel Corrosion, Wei Xing, Yibin Shan, Du Guo, Tianhog Lu, Shiquan Xi

Journal of Electrochemistry

Ordered monolayers of S- and N-containing amphipathic corrosion inhibitors were depoitod onto the surfaces of carbon steel electrode with super-molecular assembly technique. The effect of molecular aggregation of monolayers on carbon steel corrosion in 0.05 mol·cm^-3 H₂SO₄ and the mechanisms of these inhibitors were discussed in details. It was found that the transport of hydrated hydrogen ion to the surface of steel depends strongly on the inhibitor molecular aggregation in the monolayers.

Development Of The High Capacity Sintered Type Nickel Positive Electrode, Guohua Yu, Shijie Zhang, Xiaolin Wang, Jingqi Wei

Journal of Electrochemistry

By improving the design and technologies of the sintered type nickel oxide positive electrode for the NiMH batteries, We do our best to increase the sinter volume and porosity,the amount of the active materals and their utilization, so we have fabricated the high capacity sintered typo nickel electrodes fitting for the NiMH battreies. The sfecitic capacity of the lot produced electrodes is up to 550 mA/cm^-3.