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Full-Text Articles in Engineering

Analogy Method Development For Cost Estimation Of Software Design, Riyanarto Sarno, Joko Lianto Buliali, Siti Maimunah Aug 2002

Analogy Method Development For Cost Estimation Of Software Design, Riyanarto Sarno, Joko Lianto Buliali, Siti Maimunah

Makara Journal of Technology

The important aspect of planning and managing software development project is to estimate the cost of a project. There are several methods for estimating the cost of a software development project, and the Analogy method is a method which gives relatively better estimates. This paper shows that the modified Analogy method selects a closer project reference, estimates more accurate project effort and cost. This study enhances the cost estimate technique by including valid and complete cost parameters, therefore the estimate of a project cost is better than the result of the standard Analogy method.

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The Role Of Si3n4 Amorphous Phase In Nc-Tin/A-Si3n4 Nanocomposites In Increases The Hardness And Thermal Stability, Keba Moto Aug 2002

The Role Of Si3n4 Amorphous Phase In Nc-Tin/A-Si3n4 Nanocomposites In Increases The Hardness And Thermal Stability, Keba Moto

Makara Journal of Technology

The role of Si3N4 amorphous phase in nc-TiN/a-Si3N4 nanocomposites will be shown and compared with polycrystalline ZrN/Ni which has no such amorphous phase (non-composites). The presence of amorphous phase Si3N4 increases the hardness of film as well as the toughness of the bulk nanocomposites under indentation load. It has been observed that nc-TiN/a-Si3N4 nanocomposites films has higher thermal stability than ZrN/Ni polycrystalline films.

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Biodiesel's Characteristics Preparation From Palm Oil, Tilani Hamid. S, Rachman Yusuf Aug 2002

Biodiesel's Characteristics Preparation From Palm Oil, Tilani Hamid. S, Rachman Yusuf

Makara Journal of Technology

Biodiesel’s characteristics preparation from palm oil. Using vegetable oils directly as an alternative diesel fuel has presented engine problems. The problems have been attributed to high viscosity of vegetable oil that causes the poor atomization of fuel in the injector system and pruduces uncomplete combustion. Therefore, it is necessary to convert the vegetable oil into ester (metil ester) by tranesterification process to decrease its viscosity. In this research has made biodiesel by reaction of palm oil and methanol using lye (NaOH) as catalyst with operation conditions: constant temperature at 60 oC in atmosferic pressure, palm oil : methanol volume ratio …

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Development Of Hardness Measurement Procedure For Nanocomposite Nc-Tin/A-Si3n4, Keba Moto Aug 2002

Development Of Hardness Measurement Procedure For Nanocomposite Nc-Tin/A-Si3n4, Keba Moto

Makara Journal of Technology

Hardness of nc-TiN/a-Si3N4 nanocomposites which was determined by using two methods of measurements i. e. depth sensing method and remaining plastic indentation area that were magnified by using SEM (Scanning Electron Microscope) lie in the good agreement. The hardness value is not influenced by the biaxial and residual compressive stress. The measurement of the biaxial stress on the substrate shows a very small value of biaxial stress as well as the constant hardness and crystallite size against annealing temperature. Therefore, the reported hardness value here is the intrinsic value that depend on its microstructure properties.

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Bs News Aug 2002

Bs News

Building Services Engineering

No abstract provided.

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44th Rocky Mountain Conference On Analytical Chemistry Jul 2002

44th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 44th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Denver, Colorado, July 28 - August 1, 2002.

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Analysis On Possible Solution To Decreasing The Effect Of Non-Uniform Air-Gaps Due To Rotor Eccentricity In Asynchronous Machines, Dominic Chambega Jun 2002

Analysis On Possible Solution To Decreasing The Effect Of Non-Uniform Air-Gaps Due To Rotor Eccentricity In Asynchronous Machines, Dominic Chambega

Tanzania Journal of Engineering and Technology (TJET)

Rotor eccentricity introduces non-uniformity of the airgap which in turn causes additional frictional torques and losses in addition to establishing a uni-directional pulling magnetic force which is disastrous to the machine. This paper analyses the extent of the damage to the machine due to non-uniformity of the air-gap and proposes increasing the number of poles as a possible solution to arrest the effect. It is found through the analysis that as the number of poles increases the effect of eccentricity decreases.

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Evaluation Of Water Levevaluation Of Water Levels In Relation To The Design Of Coastal Structures In Tanzaniaels In Relation To The Design Of Coastal Structures In Tanzania, Alfonse Dubi Jun 2002

Evaluation Of Water Levevaluation Of Water Levels In Relation To The Design Of Coastal Structures In Tanzaniaels In Relation To The Design Of Coastal Structures In Tanzania, Alfonse Dubi

Tanzania Journal of Engineering and Technology (TJET)

Water levels on the coastline of Tanzania vary under the influence of meteorological conditions (winds and barometric pressure) and the East African Coastal Current, whose strength varies with the monsoon winds. Available tidal information is not enough to warrant statistical analysis for evaluating extreme water levels. The highest mean water springs occur at Bagamoyo and Pangani (3.93 m) and the lowest are found at Lindi (2.96 m). The highest astronomical tide is 3.7 m for Dar es Salaam and 4.6 m for Zanzibar, both of which occur during March/April and November. Measured highest water levels approach 4.80 m for Dar …

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Evaluation Of Corrosion Inhibitor On Pre-Corroded Carbon Steel In Co2 Medium By Impedance Spectroscopy, Joseph Buchweishaija Jun 2002

Evaluation Of Corrosion Inhibitor On Pre-Corroded Carbon Steel In Co2 Medium By Impedance Spectroscopy, Joseph Buchweishaija

Tanzania Journal of Engineering and Technology (TJET)

The effect of pre-corrosion of carbon steel on the performance of a commercial amine based fatty acid corrosion inhibitor, KI384, was investigated in formation water solutions saturated with CO₂ using electrochemical impedance spectroscopy (EIS) measurements. The investigation was performed at constant partial pressure of CO₂ using an autoclave system with Rotating Cylinder Electrodes (RCE). Carbon steel was pre-corroded for periods up to 7 days at 35 and 80 °C in the test solution prior to inhibitor injection. The results showed that when KI384 was applied on non-corroded carbon steel specimen, high inhibitor performance (99.8 %) was achieved independent of temperature. …

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Investigation Of Forces Acting On Plain Discs, S. M. Mpanduji Jun 2002

Investigation Of Forces Acting On Plain Discs, S. M. Mpanduji

Tanzania Journal of Engineering and Technology (TJET)

An investigation was carried out to study the mutually perpendicular forces generated by rotating and non-rotating plain discs similar to those used in disc ploughs. Experiments were conducted in a soil bin containing sand loam soil (Ryton sand) where forces were measured while changing disc rake and sweep angles. The results showed that draught forces were higher for non-rotating discs, while vertical and lateral forces were lower compared to rotating discs. Rotating discs were found to be suitable for counteracting high side forces because of less draught and higher lateral forces. The recommended optimum angles are between 8°–12° for disc …

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Comparative Analysis Of H₂S Removal Ability Of Different Calcium-Based Absorbents Under Coal Gasification Conditions, Hassan Katalambula Jun 2002

Comparative Analysis Of H₂S Removal Ability Of Different Calcium-Based Absorbents Under Coal Gasification Conditions, Hassan Katalambula

Tanzania Journal of Engineering and Technology (TJET)

Calcium-based sorbents, such as limestone and dolomite are viable candidates for capturing pollutants in an in-situ coal gasification/desulphurisation process. Recently, scallop shell is also used as a Ca-based sorbent. However, the ability in capturing pollutants varies from one type to another and it also depends on the process involved. In this study, two types of limestone, scallop shell and dolomite were characterized and studied for H₂S absorption ability under the coal gasification conditions. The characterizations were done using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Thermal analysis and Surface Area analysis. All of the samples showed a porous structure, and …

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A Comparative Application Of Telecommunication Traffic Forecasting Methods To A Backbone Link In Tanzania, M. L. Luhanga Jun 2002

A Comparative Application Of Telecommunication Traffic Forecasting Methods To A Backbone Link In Tanzania, M. L. Luhanga

Tanzania Journal of Engineering and Technology (TJET)

In this paper various mathematical models to characterize and forecast telecommunication traffic time series traffic have been applied, and the ranges of validity of the models are determined by comparing them with measured traffic data using the measurement errors criteria method which resulted into the superior model. Based on this model the ARIMA (0,2,1) model for smoothed data, the traffic forecast findings show that by the year 2006, the traffic demand will exceed the current installed capacity of 140 Mbps in the Tanzania Telecommunications Company Limited (TTCL) network along the major link between the Dar es Salaam and Dodoma backbone …

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Requirements Of A Sustainable Pavement Management System For Tanzania, N. K.M. Mushule Jun 2002

Requirements Of A Sustainable Pavement Management System For Tanzania, N. K.M. Mushule

Tanzania Journal of Engineering and Technology (TJET)

Since the introduction of pavement management concepts in mid-1960s, more than three decades ago, a considerable number of Pavement Management Systems (PMS) have been developed and implemented widely in many parts of the world. These systems differ in scope and sophistication. However, in some cases, pavement management systems have fallen into marginal use, if not into complete disuse, because of a number of reasons. One of the major reasons leading to the marginalisation or abandonment of pavement management systems, is the failure of system developers to recognise specific and unique needs of the agency or authority responsible for road management. …

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Comparison Of Repair Costs Of Two Wheel Drive Tractors Under Tanzania Conditions, S. M. Mpanduji Jun 2002

Comparison Of Repair Costs Of Two Wheel Drive Tractors Under Tanzania Conditions, S. M. Mpanduji

Tanzania Journal of Engineering and Technology (TJET)

The repair costs of 2WD tractors were investigated in order to provide important information, which lacks in the scope of agricultural mechanization in Tanzania. Previously repair cost functions established for tractors in developed countries were used for both theoretical and practical purposes. The findings of this study have revealed that repair costs of tractors vary substantially from one make to another. The prediction functions developed in this study indicated that the magnitudes of repair costs in Tanzania are higher than the repair costs established in Europe and North America. The reason for this could be either due to high cost …

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Development Of An Automated Airport Pavement Image Collection System, Chau Lee, C.F. Chen, Shu-Meng Huang, Chun-Jung Hsu, Shu-Wang Sheu Jun 2002

Development Of An Automated Airport Pavement Image Collection System, Chau Lee, C.F. Chen, Shu-Meng Huang, Chun-Jung Hsu, Shu-Wang Sheu

Journal of Marine Science and Technology–Taiwan

Airport pavement maintenance is an extremely important link in any airport pavement management system. How to quickly and effectively perform pavement surveys and data collection at today's very busy airports, while minimizing disruption to the airport's normal operation, is a major issue in airport pavement maintenance management research. This study uses a van to perform photographic surveys, and employs a global positioning system (GPS), geographic information system (GIS), image caption device, and the audio acquisition method to develop an automated airport pavement image collection system. This system currently is able to display a pavement image, slab name, and damage location …

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Effects Of Carbonation On Mechanical Properties And Durability Of Concrete Using Accelerated Testing Method, Jack M. Chi, Ran Huang, C. C. Yang Jun 2002

Effects Of Carbonation On Mechanical Properties And Durability Of Concrete Using Accelerated Testing Method, Jack M. Chi, Ran Huang, C. C. Yang

Journal of Marine Science and Technology–Taiwan

An experimental investigation was carried out to study the effect of carbonation on mechanical properties and durability of concrete. Ordinary portland concretes (OPC) with water/cement ratios of 0.58 and 0.48 and self-compacting concretes (SCC) with water/binder ratios of 0.40 and 0.36 were used in this study. Compressive strength test, splitting strength test, electrical resistivity test, rapid chloride penetration test (RCPT), open circuit potential method and alternative current (AC) impedance method were performed to estimate the properties of concrete. Test results showed that carbonation may compensate some concrete properties such as compressive strength, splitting strength, electrical resistivity and chloride ion penetration. …

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Ground Vibration During Gravel Pile Construction, Jin-Hung Hwang, Tung-Yueh Tu Jun 2002

Ground Vibration During Gravel Pile Construction, Jin-Hung Hwang, Tung-Yueh Tu

Journal of Marine Science and Technology–Taiwan

This investigation performs a field measurement of ground vibration due to gravel pile construction at a hydraulic-filled reclamation land. The ground vibrations were characterized by wave form, Fourier spectrum and response spectrum. The attenuation relation between both peak ground velocity and acceleration with distance was also derived from the measured data. An empirical method for evaluating the safe construction distance to adjacent building structures was presented based on the attenuation relation and a building vibration criterion. Vibration response spectra were also suggested for use with the spectral analysis method to determine more accurately the safe construction distance.

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Effect Of Sand Ration On The Elastic Modulus Of Self-Compacting Concrete, J. K. Su, S. W. Cho, C. C. Yang, R. Huang Jun 2002

Effect Of Sand Ration On The Elastic Modulus Of Self-Compacting Concrete, J. K. Su, S. W. Cho, C. C. Yang, R. Huang

Journal of Marine Science and Technology–Taiwan

In order to study the effect of sand ratio (S/A ratio, fine aggregate volume/total aggregate volume) on the elastic modulus of self-compacting concrete (SCC), concretes with various S/A ratios were cast and tested. Elastic moduli of SCC were compared with those of normal concrete. Slump flow test, slump test, and box test were carried out to evaluate concrete flowability. The flowability of SCC increases with an increase in S/A ratio. However, the elastic modulus of SCC is not significantly affected by S/A ratio when total aggregate volume is kept constant.

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Fuzzy Control Of Dynamic Positioning Systems For Ships, Wen-Jer Chang, Guo-Jang Chen, Yi-Lin Yeh Jun 2002

Fuzzy Control Of Dynamic Positioning Systems For Ships, Wen-Jer Chang, Guo-Jang Chen, Yi-Lin Yeh

Journal of Marine Science and Technology–Taiwan

In this paper we consider the control problem of Dynamic Positioning Systems for Ships (DPSS). It interests as a case which study in nonlinear controller design because the model exhibits nonlinear interaction in three degrees of freedom (surge, sway, and yaw) by means of main propellers aft of the ship. The DPSS system considered in this paper is modeled by a Takagi-Sugeno (T-S) type fuzzy model. By using linear feedback controller design technology, we design a nonlinear fuzzy controller for the T-S type fuzzy-based DPSS. Finally, simulation results show the utility of the present fuzzy control methodology.

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Modeling Ship,S Routing Bounded By The Cycle Time For Marine Liner, Hua-An Lu Jun 2002

Modeling Ship,S Routing Bounded By The Cycle Time For Marine Liner, Hua-An Lu

Journal of Marine Science and Technology–Taiwan

This paper addresses the problem of determining an optimal routing that bounded by the cycle time for marine liner. Through exploring the practical planning procedure of shipping company and analyzing the core of route design, this problem is realized as similar as the traveling salesman problem (TSP), but, with some specially industrial properties. A mixed integer programming model is proposed to optimize ship's routing under satisfying the relationships between the cycle time and deployed vessels with given service frequency in a week. Some constraints, besides, are organized to avoid the routing sequence has separated tours. Intuitively, we also divide the …

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Fuzzy-Art Neural Networks For Predicting Chi-Chi Earthquake Induced Liquefaction In Yuan-Lin Area, S. G. Chern, R. F. Hu, Y. J. Chang, I. F. Tsai Jun 2002

Fuzzy-Art Neural Networks For Predicting Chi-Chi Earthquake Induced Liquefaction In Yuan-Lin Area, S. G. Chern, R. F. Hu, Y. J. Chang, I. F. Tsai

Journal of Marine Science and Technology–Taiwan

In this study, a fuzzy adaptive network “Fuzz-ART”, based on adaptive resonance theory (ART) combined with fuzzy set theory is developed to evaluate liquefaction potentials induced by Chi-Chi earthquake in Yuan-Lin area. The proposed system combines the backpropagation algorithm for parameter learning and the fuzzy ART algorithm for structure learning. With the help of case studies, it is shown that the “Fuzz-ART” network is able to predict liquefaction potentials much more satisfactorily than conventional artificial neural network methods. If more data are collected, it may well evaluate liquefaction potentials induced by Chi-Chi earthquake.

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A Stability Criterion Of Time-Delay Fuzzy Systems, Cheng-Wu Chen, Wei-Ling Chiang, Ken Yeh, Zhen-Yuan Chen, Li-Teh Lu Jun 2002

A Stability Criterion Of Time-Delay Fuzzy Systems, Cheng-Wu Chen, Wei-Ling Chiang, Ken Yeh, Zhen-Yuan Chen, Li-Teh Lu

Journal of Marine Science and Technology–Taiwan

To guarantee the asymptotic stability, a stability criterion in terms of Lyapunov's direct method for multiple time-delay fuzzy interconnected systems is proposed in this paper. Each of these systems consists of a number of subsystems represented by TakagiSugeno fuzzy models with multiple time delays.

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Drbem Analysis Of Combined Wave Refraction And Diffraction In The Oresence Of Current, Sung-Shan Hsiao, Ming-Chung Lin, Nien-Chia Hu Jun 2002

Drbem Analysis Of Combined Wave Refraction And Diffraction In The Oresence Of Current, Sung-Shan Hsiao, Ming-Chung Lin, Nien-Chia Hu

Journal of Marine Science and Technology–Taiwan

A more effective numerical model using the dual reciprocity boundary element method (DRBEM) is presented to study the combined effects of wave refraction- diffraction and currents. The mildslope equation with current effects is reformulated to an inhomogeneous Helmholtz equation. Applying the conventional boundary element method to this inhomogeneous equation, the inhomogeneous part will result in a domain integral which makes the computation complicated and messy. To improve this drawback, the DRBEM is adopted to transform the domain integral to boundary integral. In order to verify the validity of this model, the relative amplitudes around a circular island without current effects …

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An Integrated Computer-Aided System And Parts Component Repository For Shaft Design Automation, Ki-Yin Chang, Gene Eu Jan, Kevin C. M. Fan Jun 2002

An Integrated Computer-Aided System And Parts Component Repository For Shaft Design Automation, Ki-Yin Chang, Gene Eu Jan, Kevin C. M. Fan

Journal of Marine Science and Technology–Taiwan

This research proposes an Object-Oriented Database (OODB) system that integrates computer-aided systems and parts component repository to automate a traditional propulsion shaft design for a shipyard. The software system is based on three concepts: an objectoriented graphic user interface, a parametric design, and a shared component database. Calculations of strength, alignment, vibrations, and sag & gap for the shaft design can therefore be completely integrated. All of the data produced in the CAD processes can be managed, integrated and applied in the OODB system. Furthermore, to easily integrate the systems developed at different periods of time, a Common Object Request …

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Bs News Jun 2002

Bs News

Building Services Engineering

No abstract provided.

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Syntheses And Photoluminescence Of Zinc Oxide Polyaniline Coaxial Nanowires And Their Array, Zhi-Xin Zheng, Yan-Yan Xi, Ping Dong, Huai-Guo Huang, Jian-Zhang Zhou, Lin-Lin Wu, Zhong-Hua Lin May 2002

Syntheses And Photoluminescence Of Zinc Oxide Polyaniline Coaxial Nanowires And Their Array, Zhi-Xin Zheng, Yan-Yan Xi, Ping Dong, Huai-Guo Huang, Jian-Zhang Zhou, Lin-Lin Wu, Zhong-Hua Lin

Journal of Electrochemistry

A novel nanomaterial, zinc oxide (ZnO) and polyaniline (PANI) coaxial nanowires and their array in the template, was synthesized using anodic aluminum oxide (AAO) membrane as template. The morphology of these coaxial nanowires was observed with transmission electron microscope (TEM). The experiments on photoluminescence (PL) of coaxial nanowires and their array in AAO membrane show that the visible emission band of ZnO shifts from 530 nm to 400 nm and the luminescence is enhanced for the coaxial nanowires array in AAO membrane,and the visible emission band shifts to a lower wavelergth (385 nm) for coatial nanowires in NaOH solution. Possible …

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Electrochemical Properties Of Mixed Metal Oxide Coated Titanium Anodes In Seawater, Ting-Yong Wang, Li-Kun Xu, Guang-Zhang Chen May 2002

Electrochemical Properties Of Mixed Metal Oxide Coated Titanium Anodes In Seawater, Ting-Yong Wang, Li-Kun Xu, Guang-Zhang Chen

Journal of Electrochemistry

Mixed metal oxide coated titanium anodes prepared by thermal decomposition were characterized by scanning electron microscopy and electrochemical measurement, while the consumption rate of an anode was also measured in seawater. In order to examine the practical performances of mixed metal oxide-coated anodes, a simulating test on floating dock in seawater has also been carried out. The SEM results indicate that oxide layers exhibited a cracked-mud morphology which endows the anode with good electrocatalytic activity. The electrochemical measurements showed that mixed metal oxide-coated anodes exhibit excellent electrochemical activity and electrochemical stability in seawater. Owing to good corrosion resistance and low …

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The Preparation And Characterization Of Growing Preferentially Cds Nanopartile Film, Huai-Guo Huang, Yan-Yan Xi, Zhi-Xin Zheng, Jia-Wei Yan, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin May 2002

The Preparation And Characterization Of Growing Preferentially Cds Nanopartile Film, Huai-Guo Huang, Yan-Yan Xi, Zhi-Xin Zheng, Jia-Wei Yan, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

CdS nanoparticle films were prepared on the PANI film, PATP film, Au film and ITO respectively by constant current deposition or current impulse method, and their structure and character were also studied. The results show that the substrates influence the structure and character of CdS particle film.

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Corrosive Electrochemical Behavior Of Carbon Steel In Microbiological Medium, Jing Liu, Hong-Bo Fan, Hai-Ping Xu, Jia-Shen Zheng, Li-Ming Xu, Zong-Qiang Mao May 2002

Corrosive Electrochemical Behavior Of Carbon Steel In Microbiological Medium, Jing Liu, Hong-Bo Fan, Hai-Ping Xu, Jia-Shen Zheng, Li-Ming Xu, Zong-Qiang Mao

Journal of Electrochemistry

Sulfate-reducing bacteria (SRB)grows and propagates, PH of the solution is dropped from 7.5 to 5.8, and forms the biofilms on carbon steel in culture medium. The micro-environment on the surface of carbon steel is changed under the biofilms, the factors accelerate the formation of the pitting corrosion. When the biofilm on carbon steel is cleaned out, the surface of carbon steel have the non-uniform pitting corrosion. The activity of SRB and the porous structure of biofilms induced the initiation and development of the pitting corrosion of carbon steel. The process of microbiologically induced corrosion (MIC) involves the development of SRB …

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Recent Developments In The Electrolyte For Lic6/Electrolyte/Cathode Battery, Cui-Ying Wang, Sheng-Liang Zhao, Guang-Ming Zhu, Jin-Kua You, Zu-Geng Lin May 2002

Recent Developments In The Electrolyte For Lic6/Electrolyte/Cathode Battery, Cui-Ying Wang, Sheng-Liang Zhao, Guang-Ming Zhu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

We present a reviewed the development and status of electrolyte for LiC 6/electrolyte/cathode battery. The effect of the salt, solvent, additive and impurity on the conductivity of the electrolyte, formation of the solid-electrolyte-interphase (SEI) and cycle life of the battery were described.

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