bluuebunny/crossref_metadata_2025 huggingface dataset:
Topology and Functions of Large-Scale PV Power Station Monitoring and Control System
Authors: Yao Hong Chun , Yin Liang , Huang Ming Yu
Published: September 2013

According to the development status of large-scale PV power station, this paper expatiates the topology and functions of the monitoring and control system of large-scale PV power station, The system consists of monitoring center, fiber optic ring network and control subnet, and the main functions are SCADA (supervisory control and data acquisition), AGC (automatic generation control), AVC (automatic voltage control), system state assessment, equipment maintenance, and power generation benefit analysis. The system is flexible and reliable, and will promote the efficiency of operation and maintenance of large-scale PV power station.
The Research of Intelligent High-Pressure Water Jet Target Detection Experimental System
Authors: Yang Hao , Niu Meng Meng , Zhang Dong Su , Li Jing Xi
Published: September 2013

As a new technology, high-pressure water jet technology is widely used in various fields .However high-pressure water jet is used for the detection of the target material in China and abroad, is still in its infancy. So this article studies on high-pressure water jet target material detection technology .This paper aims to study the target object detection experimental device and the follow-up process of detect sound signal.
Research on Figure Test and Skew Kurtosis Test of the Normal Distribution
Authors: Wang Jun Sheng , Wu Jin Huang , He Yi Zhou , Zheng Jian Ting
Published: September 2013

The object of the statistical analysis is the statistical information. To correctly identify the type of statistical information is the most important prerequisite for rational use of statistical analysis methods. In this paper, the common methods for normality test are introduced theoretically. And the figure test and partial kurtosis test of normal distribution are proposed with detailed testing steps, suitable situation and mathematical model. It is demonstrated by simulation that both have good test results and practical value.
Study on Network Public Opinion Monitoring Based on .NET Framework
Authors: Zhu Yan
Published: September 2013

With the fast development of Internet, the ideological and political work in colleges is faced with new opportunity and challenge. Network public opinion has become the key impact factors of college students' ideological and political and the behavior, so that the network public opinion monitoring also has become one of the main subject in college ideological and political education reform for experts and scholars in the field of education. Firstly, based on the characteristics of the network public opinion and its production process, the article analyzes the penetration relations produced by the network public opinion on modern ideological and political education. On this basis, combining the characteristics of modern ideological and political education in colleges, it has put forward constructing a new mode of education from the multi-angle field of view based on .NET framework. Finally, by the confirmatory analysis, ideological and political education under the mode can better guide the students ideological and political education work.
Fault Diagnosis of Power Transformer Based on Adaptive Differential Evolution and Least Square Support Vector Machine
Authors: Li Zi Pin , Peng Hui
Published: September 2013

Least square support vector machine (LS-SVM) can solve small sample, high-dimensional and non-linear multi-classification problem well, so it is applicable to the power transformer fault diagnosis. However, the parameters of LS-SVM have significant effect on the classification results.In this paper, the adaptive differential evolution algorithm (ADE) is applied to optimize the parameters of LS-SVM. The scaling factor and crossover rate are adjusted dynamically in the whole evolution process, so the robustness of the algorithm is improved greatly. The optimized LS-SVM is applied to fault diagnosis of power transformer, the results obtained demonstrate superiority of the proposed approach.
FTA-Based Reliability Measurement of Test-Bed System
Authors: Lin Qi , Chen Yong
Published: September 2013

The significance of reliability researches are described first. It is necessary to know concepts of reliability without a doubt, and most common measures of reliability are discussed, including reliability function and failure rate. It emphasizes two important analysis approaches: Failure Mode, Effects, and Criticality Analysis (FMECA) and Fault-Tree Analysis (FTA). Last, it provides the quantified result of reliability analysis of a test-bed system with FTA-based RiskA software as a case study, which shows the usefulness of FTA-based reliability measurement.
Application of Wireless Sensor Technology in the Training of Martial Arts and Specification Motion Detection
Authors: Shao Chang Kun
Published: September 2013

With the development of the computer wireless communication technology, wireless sensor detection is being widely applied to engineering practice. Combined with the advantages and disadvantages of the two algorithms LEACH and PEGASIS, this paper proposes a new algorithm BEAHR algorithm. At the same time, this paper establishes mathematical model algorithm of wireless network detection energy consumption for BEAHR algorithm. Finally, this paper calculates the numerical value of the three algorithms LEACH, PEGASIS and BEAHR by using the general numerical simulation software of MATLAB software. Through the numerical simulation experiments, it is found that with the increase of time, the average energy consumption of three algorithms will also be increased. Among them, the fastest increase of energy consumption is LEAC. However, the energy consumption of BEAHR algorithm is small. When the time is 1000 s, power consumption is 0.5 J, which verifies the validity and reliability of BEAHR algorithm and proves that BEAHR algorithm has the excellent performance to save energy and improve the network life cycle.
Extraction and Purification of Isoquinoline from Wash Oil
Authors: E Yong Sheng
Published: September 2013

Isoquinoline is a basic chemical raw material, which has wide applications.This paper introduces the current isoquinoline technology of extration and purification from wash oil. I use the residual oil after producting quinoline as raw material, get isoquinoline by distillation twice. The content of isoquinoline is higher than 98%.The total yield is 76.9%, which is higher than current domestic production levels.
Design of Radar Transmitter Test Device
Authors: Du Wei Ming , Liu Cai Bin , Liu Guo Hong
Published: September 2013

Following the test work is difficult and complex in the modern radar maintenance support, the automatic testing of radar is necessary for the radar maintenance man. Radar transmitter test device is designed to test the work state and performance parameter of radar transmitter off-line or on-line, and means while it has expert default diagnosis system to analyze the key signals and locate typical faults. The test device is accordingly seen as a good means to middle radar maintenance support. The design of radar transmitter test device is given, its hardware solution and software solution is explained. And finally the reliability and expansibility of the device is discussed at last.
Software System for Automotive Wiring Harness Testing Based on Virtual Instrument
Authors: Feng Wei Dong , Xu Wen , Wang Xian Hong
Published: September 2013

Development of modern information technology provides a technical platform for the wide application of virtual instrument technology. Here we apply virtual instrument technology to test the faults of wiring harnesses, such as short circuit , broken circuit , wiring error , poor contact, poor insulation and unsatisfactory impedance and monitor the product quality at real-time. We use LabVIEW of the graphical programming language based on virtual instrument as the tool to develop the testing software. It realizes the functions such as the data acquisition, storage, analysis and display, single point wiring harness testing, all wiring harness testing, impedance testing, query and statistics, etc. We uses software instead of hardware so that functions can be added or cut down at random without adding any other hardware facilities.
Particle Swarm Optimization and Adaptive Wavelet Theory for Vibration Signal Application in Fault Diagnosis of Gearbox System
Authors: Chen Han Xin , Zhang Yan
Published: September 2013

Gearbox system is widely used in mechanical industry,but serious failure is always occurred in the gearbox system. So it is very necessary to diagnose the fault of gearbox in the early-age avoiding economic losses. In this paper, a novel method for extracting the characteristic information from the vibration signal of gearbox system based on the particle swarm optimization (PSO) algorithm and adaptive wavelet theory is proposed.
Multi-Agent Information Interaction Research for Distribution Dispatch Monitoring
Authors: Qu Zhi Jian , Guo Liang , Ling Hong Ping , Chen Ge , Liu Li
Published: September 2013

In allusion to the transmission difficult difficulties problem of massive monitoring information flow, due to numerous on-line processing points and quick variation of operating parameters in distribution network monitoring dispatching, an new asynchronous processing method for batch information based on multi-agent alliance technology is proposed. Multi-agent alliance Platform is constructed by means of designing JACK software. Then using CIM-mapping technology and news event asynchronous trigger technology, massive data interactive real-time processing is implemented. Taking the monitoring system for 10kV railway distribution network as example, the synchronous interaction and performance tests are carried out for 10000 analog quantities and state quantity measurement data, the transmission interaction processing time is 582.08ms.
IR and Raman Spectroscopic Studies on Three Mineral Drug Montmorillonite Powders for Children
Authors: Liu Bing Yang , Xing Man , Bai Yu Shu , Dong Lei , Wang Sen , Liu Xiao Dong
Published: September 2013

IR and Raman spectra of three kinds of mineral drug montmorillonite powders (brands Biqi, Smecta general, Smecta strawberry flavour) commercially available for children are obtained to tell the true from the false through checking the spectral information of the active ingredient (montmorillonite) and pharmaceutical excipients (glucose, saccharin sodium, vanillin and strawberry essence). It is found that net contents of the active ingredient in all three drugs maybe really high and even the cheapest brand is also with a high quality. From this study one can see that the IR spectroscopic method is more suitable for this kind of drug identification than the Raman one using the present Raman spectroscope because strong fluorescent signals excited by lasers on the pharmaceutical excipients can generally cover up the fingerprint signals of the active ingredient.
Hardware System for Automotive Wiring Harness Testing Based on DAQ Instrument
Authors: Feng Wei Dong , Pan Ji Hui , Xu Wen
Published: September 2013

With the development platform based on Advantech DAQ board, we have completed the design of multi-channel analog switch, decoding circuit and impedance testing circuit and built a good hardware platform for the automotive wiring harness testing system. Testing software is used to import different values into the digital I/O of data acquisition card of the hardware of to choose the tested points and then the voltage signal is read from every loop and the voltage signal is sent into the computer. Analyzing, processing, displaying is done by the testing software so that the hardware system becomes the development platform for Lab-VIEW software application.
Composite Environment Monitoring System for Edible Fungus Cultivation Based on ZigBee Technology
Authors: Guan Cheng Bo , Liu Jing Yun , Hu Li Shuan , Zhang Qin
Published: September 2013

The existing wired monitoring systems for edible fungus cultivation has some shortcomings such as complex wiring, unsatisfied function, low automatic level and so on. This paper developed a composite environment monitoring system for edible fungus cultivation based on wireless sensor network with ZigBee technology. Through a star wireless sensor network topology, this system acquired the temperature and humidity of cultivation environment, as well as the growing image of edible fungus. Meanwhile, according to the growing nature of edible fungus, a control strategy for cultivation environment was developed and integrated in the system. The proposed composite environment monitoring system provided a good solution for edible fungus cultivation industry.
Study on Beam Combining Technology for Lighting Source of Laser Active Detection and Imaging Application
Authors: Zhou Bin , Fan Gui Hua , Liang Dan Hua , Zhang Ting Hua
Published: September 2013

Aiming at the application of lighting source for laser active detection and imaging application, spectral beam combining technology is adopted in order to meet the requirements of the light spots which have an excellent performance in far field. The selection principle of beam combining methods is expound. Furthermore, the beam combining models are built, and the performance in 5km is simulated in the research. The results of analysis indicate that only Spectral Beam Combining (SBC) of laser diode could combine different wavelengths laser beams and have an obvious advantage in speckle reducing, which can lead to a much more homogeneous image in range gated laser active imaging application.
Reusable Electrochemical Aptasensor for Sensitive Detection of Small Molecules Based on Structure-Switching Hairpin Probe
Authors: Zhang Song Bai , Han Pei Zhen , Lu Ping , Hu Xia , Zheng Li Ying , Liu Xue Wen , Shen Guang Yu , Lu Ji Lin , Qiu Li Ping , Zhou Shi Biao
Published: September 2013

A reusable electrochemical biosensing strategy based on structure-switching hairpin probe for the detection of small molecules is proposed using cocaine as the model analyte. Aptamer probe hybridized with the immobilized signal probe to form DNA duplex. When target small molecule was added, competition between target molecule and the signal probe with the aptamer probe happened, which induced the signal probe from stretched duplex to hairpin structure. By measuring ac current voltammetry, the target molecule can be sensitively detected in a linear dynamic range from 1 nM-1000 nM with a low detection limit of 0.7 nM. In particular, the biosensor can be easily regenerated by melting in hot water, making it reusable.
Winter PBL Aerosol Profiles at Bejing
Authors: He You Ming , Yang Hui , Yan De Bin , Chen Pei Bin , Ye Jie Song , Li Xin Jian , Hao Yan Jun , Sun Yan Fei , Zhao Xue Song
Published: September 2013

The vertical distribution of aerosol extinction coefficients within winter planetary boundary layer (WPBL) over the observation site are shown in this paper, and the heights of PBL are discussed. The data indicates that the aerosol over the measurement site is almost trapped within PBL and troposphere layer and is rather stable, and the multi-layer structure of the aerosol distribution is obvious.
Advances in Graphene-Based Fluorescent Sensors for Heavy Metals
Authors: Luo Ling Ling , Zhou Min , Yang Jing Yi , Zhong Shun Xian , Chen Jian Rong
Published: September 2013

The excellent photophysical feature makes graphene widely applied in fluorescent sensors. Here, we summarize recent progress in the design of graphene-based sensors, especially the increase in the sensitivity of the detection of heavy metals. In addition, we also give an overview of the development of graphene-based sensors in the future.
Microstructure and Mechanical Properties of 16Cr-2Ni Stainless Steel Fusion and Solid State Welds-Influence of Post Weld Treatments
Authors: Madhusudhan Reddy G. , Rajasekhar Adula
Published: September 2013

Many critical applications in chemical equipment, aircraft and ordinance demand a material of construction with high strength and good corrosion resistance. Frequently the strength requirement exceeds that obtainable with austenitic or ferritic stainless steel and it is necessary to use one of the martensitic stainless steels. Since martensitic stainless steels are structural materials, weldability has been an important consideration in their development. AISI 431 is one of the most potentially attractive steels in this class used extensively for parts requiring a combination of high tensile strength, good toughness and corrosion resistance. Although this material has been used for many years, little information is available on the welding behavior of these steels. Further, data on electron beam (EB) welding and solid state welding process like friction welding are scarce. The lack of knowledge constitutes a potential drawback to the more widespread use of these steels. Hence, a study has been taken up to develop an understanding on the electron beam welding and friction welding aspects of martensitic stainless steel type AISI 431. Various kinds of post weld heat treatments (PWHT) were investigated to determine their influence on microstructure and mechanical properties. Weld center in EB welding resulted a cast structure consists of dendritic structure with ferrite network in a matrix of un-tempered martensite. In friction welding, the weld center exhibited thermo-mechanical effected structure consists of fine intragranular acicular martensite in equiaxed prior austenite grains. In both the welding processes, post weld tempering treatment resulted in coarsening of the martensite which increases with increase in tempering temperature. In the as-weld condition, welds exhibited high strength and hardness and poor impact toughness. Increase in impact toughness and decrease in strength and hardness is observed with an increase in tempering temperature. The hardness of EB welds increased with increase in the austenitizing temperature up to 1100 °C and a marginal decrease thereafter was observed. Double austenitization after double tempering resulted in optical mechanical properties i.e., strength, hardness and toughness.
Distortion and its Control in Welding of Stainless Steel Structures - Case Studies
Authors: Raju N. , Ravichandran G. , Sudharsanam V. , Easwaran R.
Published: September 2013

Distortion is a perennial problem faced by engineers engaged in welding fabrication. The shape change deformations and change in the dimensions that occur after welding is termed as distortion, leading to various undesirable consequences. So there exists a necessity to control distortion within limits. When distortion exceeds acceptable limits, correction of distortion after the complete fabrication results in major reworking operation that consumes both fabrication time and cost. Distortion control in complex structures has always been a challenge to fabrication engineers, dealing with stainless steels. To arrive at an appropriate control method, an in-depth analysis of the shape change deformation behavior of the component and adaptation of appropriate methods to control distortion are essential. In this study, two circular components made of stainless steel have been taken up for control of distortion. The first structure is the labyrinth used in hydro turbine assembly that consists of a ring type of flange made of martensitic stainless steel (ASTM grade A240 S41500) welded with a shell type web using grooved fillet welds. The size of the welded assembly is huge and the quantum of weld is very high leading to heavy distortion that often required to be corrected by way of weld build-up and subsequent machining. The second one is the vortex finder assembly which is a part of cyclone separator that is used to separate the fine particles of coal from coarse ones for use in the combustion chamber of typical Circulating Fluidised Bed Combustion (CFBC) boilers. This is again a cylindrical structure with three shells joined with three flanges and supported by stiffeners. The structure is made of special grade Austenitic stainless steel to withstand high temperature. In both the structures, most of joints are of Tee-joints with fillet welds. During fabrication of these assemblies, the angular tilt, local waviness and the diameter variation were the major issues. Correction after fabrication is not viable considering the configuration and shape of the component. This calls for control of distortion during fabrication itself. Towards this, a suitable welding procedure using an appropriate weld sequence was evolved after studying the weld details of the components. This weld sequence was implemented in-situ in actual components. During fabrication on-line monitoring was carried out and course corrections were provided. After implementation of the weld sequence, it was found that the distortion of the component could be reduced and contained well within the permissible limits. This made the extra rework redundant thus leading to a significant reduction in the cycle time of manufacture of the component. The details of the methodology adopted are described in this paper. Keywords: Labyrinth assembly, vortex finder assembly, stainless steel welding, distortion, T joint, grooved fillet weld, angular tilt, weld sequence.
Case Studies on Field Repairs of Stainless Steel Components in Refinery
Authors: Negi B.S.
Published: September 2013

Stainless steels (SS) possess excellent corrosion, creep and high temperature oxidation resistance and are invariably used in refinery for construction of heater tubes, tube supports, Heat exchanger bundles, piping and internal lining of pressure vessels. Ferritic stainless steel type 405 is used for column strip-lining, martensitic stainless steel type 410 is used for column trays and heater tubes and austenitic stainless steel family is used very extensively for lining, piping, heat exchanger, heater tubes and tube supports. On-stream and turnaround condition monitoring of plant and equipment are carried out for health assessment and mitigation of premature failure. However, catastrophic failures of stainless steel due to stress corrosion cracking, thermal fatigue and stress relaxation cracking are encountered in addition to bulging and cracking of strip-lining. Field repairs of these components are required to be done.
Stainless steels are difficult to weld due to low thermal conductivity, higher coefficient of thermal expansion, fissuring and solidification cracking problem during welding. Lower heat input and fast cooling facilitate the welding process. Welding of service exposed stainless steels is more challenging, as it has already undergone metallurgical degradation. Welding of stainless steels is carried out using TIG and SMAW process with matching electrode after establishing the welding specification procedures and welders qualification. Field repairs of stainless steels components are also attempted with original procedures and in case of difficulties, a buttering layer of inconel (ERNiCr3) or ER 309Mo is provided on the welding surface before using matching electrodes. Quality assurance of weld joint is ensured by stage-wise inspection and non-destructive testing. Dye penetrant test of root run and radiographic examination of final weld joint are most common. Post weld heat treatment is done as per code requirement.
This Paper highlights three case studies on field repairs of stainless steel components in refinery. 1. Welding procedure followed for repair of bulged and cracked SS 316 strip-lining and cladding on carbon steel backing material. It is a dissimilar welding of SS 316L with degraded carbon steel. 2. Field welding of SS 347 Piping components, which has undergone thermal relaxation cracking at fillet joints. 3. Welding repair of SS 310 cast heater tube support conforming to A 297 Gr HK 40. The Paper also presents brief failure analysis with reasons and remedies.
Dynamic On-Line Control of Stainless Steel Making in AOD
Authors: Deo Bahma , Kumar Satish
Published: September 2013

A new dynamic control model based on simultaneous mass transfer of C, Cr, and Mn and dynamic heat balance is developed. It allows dynamic adjustment of argon-oxygen ratio. The model is implemented through Level II control system. The total operating period of one heat is divided into five different stages: charge calculation, first blow period, second blow period, third blow period and, lastly, the reduction stage. The charge calculation model, based on heat balance, mass balance and the costs decided the optimum charge mix to start with. Both linear and non-linear regression models are used to predict the temperature and composition of bath at the end of first blow period. The second blow and the third blow periods use the dynamic models for predicting the chemical composition and temperature. In the model for reduction stage (final stage) the amount of reduction mixture is determined for obtaining maximum recovery of Cr and Mn from slag. On-line testing of the dynamic models was carried out on the shop floor. The integration of models with the Level II control system using Supervisory Control and Data Acquisition System (SCADA) are discussed. User friendly HMI are developed such that the operators can easily use it during the regular operation on shop-floor. This is the first time that a full dynamic control system was implemented in India for the AOD process.
Studying the Mechanism behind Stress Corrosion Cracking of Non Sensitized 304L Austenitic Stainless Steel
Authors: Ghosh Acharyya Swati , Kumar M. Kiran , Kain Vivekanand
Published: September 2013

The susceptibility of non sensitized 304L stainless steel (SS) components towards stress corrosion cracking (SCC) has been studied here in the light of the significant role played bysurface working operations. The plant experience shows that the fracture surfaces of non sensitized 304L stainless steel components have no signs of carbide precipitation. However, heavy plastic deformation has been evidenced in the form of high density of slip bands on the surface up to a depth of about 100 μm with high tensile residual stresses near the surface. The present study has established that the primary cause of the increase in SCC susceptibility is the heavy plastic deformation near the surface and high magnitude of tensile residual stresses which is a consequence of the surface finishing operations like machining and grinding. In this study, solution annealed 304L stainless steel has been subjected to a) surface working operations like machining and grinding and b) bulk deformation operations such as 10 % cold rolling operation. The materials in different conditions where then subjected to detailed a) microstructural characterisation, b) electrochemical characterisation and c) tests for determining the stress corrosion cracking susceptibility. The distinct differences in the micro structure as a result of bulk deformation vs. surface deformation of 304L austenitic stainless steel were highlighted and correlated to the susceptibility towards stress corrosion cracking. The effect of surface working on the nature and composition of high temperature (300 °C and 10 MPa) oxide formed on 304L stainless steel has been studied in-situ by contact electric resistance (CER) and electrochemical impedance spectroscopy measurements using controlled distance electrochemistry technique in high purity water (conductivity < 0.1 μScm-1) at 300 °C and 10 MPa in an autoclave connected to a recirculation loop system. The results highlighted the distinct differences in the oxidation behaviour of surface worked material as compared to solution annealed material in terms of specific resistivity and low frequency Warburg impedance.
Macro and Micro Electrochemical Techniques to Study Influence of Sigma Phase Formation in a Duplex Stainless Steel
Authors: Sunil Kumar B. , Kain Vivekanand
Published: September 2013

In the present study macro electrochemical (anodic polarization) and micro electrochemical (scanning electrochemical microscopy (SECM) area scan measurements at passive potential) techniques have been used to study the influence of sigma phase and/or the resultant chromium depletion regions on localized corrosion behavior of aged type 2205 duplex stainless steel (DSS) in neutral chloride ion solution. DSS type 2205 was subjected to aging at 750 °C for 30 min, 10 h and 48 h. The formation and growth of the sigma phase with heat treatments was assessed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction. The influence of formation of sub-microscopic and bulky sigma phase on intergranular corrosion (IGC) and pitting corrosion was investigated by various electrochemical techniques including electrochemical potentiokinetic reactivation (EPR), potentiodynamic polarization and SECM. Apart from EPR tests, ASTM A 262 Practice B test was carried out to evaluate the presence of chromium depletion regions with heat treatments. The results showed that with increasing aging duration, the degree of sensitization and IGC rates initially increased and then decreased with heat treatment. The pitting potentials decreased continuously with increase in aging duration up to 10 h as assessed by potentiodynamic polarization tests. The SECM area scan measurements showed more metastable pitting corrosion events for 30 min and 10 h aged specimens compared to the 48 h aged specimen at passive potential in 0.1M neutral chloride ion solution.
Microbial Effects on Heat Treated 316L Weldments in Marine Water
Authors: Suvarna Kripa , Udupa K. Rajendra , Surendranathan A.O.
Published: September 2013

Austenitic stainless steels are susceptible to microbiologically influenced corrosion (MIC) when they are in contact with sea water. This is due to the changes in the chemistry of the environment at the metal surface because of the settlement and activities of microorganisms. The thrust of our work was in understanding the changes in the electrochemical behaviour of a type 316L stainless steel in the presence of a natural biofilm as well as the influence of metallurgical characteristics on microbial adhesion and MIC. The presence of a biofilm on material surface can influence the corrosion behaviour since the value of a given parameter such as temperature, pressure, concentration of a solute and pH at the water /substrate interface under the biofilm may be different from that in the bulk environment. The non-uniform nature of biofilm thus helps in generating heterogeneity in the environment at the surface. Thus, biofilms are known to aid in the initiation of corrosion, change the mode of corrosion or cause changes in the corrosion rate. Bacteria Arthobacter nicotinae (An) and algae Chlorella pyrenoidosa (Cp) were used for the study and bio film formed due to these showed pit initiation and increase in corrosion rate as time proceeds. 316L base metal (BM) and weld metal (WM) as received and after heat treated at 450°C for 10000 hours were studied and corrosion evaluation was done. Heat treated WM showed severe response to corrosion compared to as received WM. Key Words: MIC, AISI 316L SS, biofilm, weld metal, localized corrosion.
A Comparative Study of Semiconducting Behavior of Passive Film of High Nitrogen and Ni and Mn Free Stainless Steels in 3.5 wt. % NaCl
Authors: Arya S.B. , Raja V.S. , Tiwari A.N.
Published: September 2013

The semiconducting property of passive films formed on Alloy 1 (18Cr-2Mo-1N)], Alloy 2 (17.5Cr-3Mo-0.5N)] and Alloy 3 (Type 316 SS) were studied by using the Mott-Schottky (M-S) approach in 3.5 wt. % NaCl solution of pH 2, 7 and 12. The M-S analysis shows that the film acts as n - type and p - type semiconductors across the potential range. The donor density of Alloy 1 has been found to be lower by about 31 %, 11 % and 6 % as compared to that of Alloy 2 at pH 2, 7 and 12 respectively. However; Alloy 3 has higher donor density 44 %, 27 % and 30 % in comparison with Alloy 1. The donor density of Alloy 3 found to be greater about 21 %, 18 % and 25 % to the Alloy 2 at pH 2, 7 and 12 respectively. These results indicate that the sensitivity of electrolyte composition and the presence of alloying elements like nitrogen and nickel on the donor density of passive film. High nitrogen stainless steels exhibited a lower donor density that corresponds to good protectiveness, more stable passive film which is in agreement with a low passive current density (ipass), higher pitting potential (Epit) and polarization resistance (Rp).
Influence of Intrinsic Solidification Behaviour on Quality of Stainless Steel Cast and Rolled Products
Authors: Ray Santanu Kr.
Published: September 2013

Recent advances in continuous casting have facilitated remarkable improvement in the quality of cast steel. The focus of the present paper is directed towards understanding of the influence of chemistry and intrinsic solidification behaviour on the different quality issues of stainless steel. An attempt has been made, wherever possible in quantitative terms , to correlate the chemistry and the process parameters with the quality factors. The relevant theoretical background has been touched upon. Understanding has been developed on the role of the ratio of nickel equivalent and chromium equivalent. This factor can be used to represent the chemistry of any stainless steel grade. Under similar casting conditions, specific problem of mould sticking , strand bulging , or depression formation has been explained invoking this chemistry factor. Each quality issue owes its genesis to interaction between the high-temperature strength and ductility of the solidifying shell during casting. The important roles of micro-segregation , the effective shell thickness during the early stage of casting , and the temperature range of transformation for δ-ferrite to austenite have been highlighted. An approach of grade-specific casting practice has been suggested to formulate the specific casting parameters. The developed understanding has been utilised to address specific quality problems in continuously cast slabs and rolled products of different stainless steel grades. This integrated understanding can be useful for ensuring the quality of stainless steel of any chemistry.
Nitrogen Enhanced 316LN Austenitic Stainless Steel for Sodium Cooled Fast Reactors
Authors: Jayakumar Tammana , Bhaduri A.K. , Mathew M.D. , Albert Shaju K. , Kamachi Mudali U.
Published: September 2013

For the future sodium-cooled fast reactors (SFRs), which are envisaged with a design life of 60 years, nitrogen-enhanced 316LN austenitic stainless steel (SS) with improved high-temperature properties is being developed. To optimize the enhanced nitrogen content in 316LN SS, the effect of nitrogen on its tensile, creep and low cycle fatigue behavior has been investigated. For different heats of 316LN SS containing 0.07-0.22 wt% nitrogen, the tensile and creep properties increased with increase in nitrogen content, while low cycle fatigue properties peaked at 0.14 wt% nitrogen. Finally, based on the evaluation of the hot cracking susceptibility of the different heats of 316LN SS with varying nitrogen content, using the Varestraint and Gleeble hot-ductility tests, the nitrogen content for the nitrogen-enhanced 316LN SS has been optimized at a level of 0.14 wt%. The 0.14 wt% nitrogen content in this optimised composition shifts the solidification mode of the weld metal to fully austenitic region, including that due to dilution of nitrogen from the base metal, thereby increasing its hot cracking susceptibility. This necessitated development and qualification of welding electrodes for obtaining weld metal with 0.14 wt% nitrogen by optimising the weld metal chemistry so as to obtain the requisite delta ferrite content, tensile properties, and very importantly impact toughness both in the as-welded and aged conditions. Studies on localised corrosion behaviour of nitrogen-enhanced 316LN SS indicated the beneficial effect of nitrogen addition to sensitization, pitting, intergranular corrosion, stress corrosion cracking and corrosion fatigue.
Applications of Stainless Steel in Automobile Industry
Authors: Saha Podder Arijit , Bhanja Amritraj
Published: September 2013

Mounting energy crisis, stringent emission law and strict safety rules have guided car manufacturers to improve strength/weight ratio of the vehicle, thereby promoting several applications of stainless steels in the car body. Moreover, use of stainless steels also improves aesthetics and minimizes life cycle cost. In automobiles, presently 45-50% of stainless steels are used in exhaust systems. To improve efficiency, complex designs are being used and performance criteria of the material are getting tougher. New techniques such as tube hydroforming are also being explored using austenitic stainless steel for the complicated designs utilizing the benefits of high ductility of these grades. Since corrosion resistance remains fundamental requirement for these applications, selection of grades and stabilizing elements are critical for such applications and depend primarily on operating conditions. Different grades and effect of their composition on elevated temperature strength, creep strength, endurance limit and corrosion resistance are presented. Stainless steels are also being used in other applications such as fuel tank, bumper, chassis for buses and trucks. With the development of new varieties of austenitic, ferritic and martensitic stainless steels, automotive industry is intensively exploring their potential.
Rate of Rare Earths Leaching in HCl, H2SO4 and HNO3
Authors: Meor Sulaiman Meor Yusoff
Published: September 2013

Leaching plays an important role in the recovery of rare earth elements. A study on optimizing the relevant parameters such agitation, leaching time and temperature in the dissolution of these elements in HCl, H2SO4 and HNO3 acids were carried out. The recovery of the rare earths is much depended upon the type of acid used in the leaching system. The H2SO4 system shows the highest leached with a rate of 82% while the leaching rate recorded for HCl and HNO3 system were lower at 67% and 59% respectively. Comparative rate of leaching study was also done on the light and heavy rare earths for the three different acid leaching systems and the result shows that the light group has a better rate of leaching than the heavy group.
Thermal Management of Electronic Components by Using Computational Fluid Dynamic (CFD) Software, FLUENTTM in Several Material Applications (Epoxy, Composite Material & Nanosilver)
Authors: Mazlan M. , Rahim A. , Al Bakri Abdullah Mohd Mustafa , Razak W. , Zubair A.F. , Najib Y.M. , Bakir Azman A.
Published: September 2013

This paper presents the thermal management of electronic components, microprocessor by using three dimensional numerical analysis of heat and fluid flow in computer. 3D model of microprocessors is built using GAMBIT and simulated using FLUENT software. The study was made for four microprocessors arranged in line under different types of materials, inlet velocities and package (chip) powers. The results are presented in terms of average junction temperature and thermal resistance of each package The junction temperature is been observed and it was found that the junction temperature of the microprocessors is not exceed 70o C. It also found that the (chip) powers and inlet velocities are the most important elements to control and manage the junction temperature. The strength of CFD software in handling heat transfer problems is proved to be excellent.
A New Invention of Thermal Pad Using Sol-Gel Nanosilver Doped Silica Film in Plastic Leaded Chip Carrier (PLCC) Application by Using Computational Fluid Dynamic Sofrware, CFD Analysis
Authors: Mazlan M. , Rahim A. , Al Bakri Abdullah Mohd Mustafa , Iqbal M.A. , Razak W. , Salim M.S.
Published: September 2013

Thermal pad is new technology in the world that been used in PLCC in order to reduce junction temperature to the minimum level in electronic components. Thermal Pad was made by using nanosilver as main material. nanosilver silica films were applied on PLCC using a sol-gel process and heat-treated at different temperatures. In electronic industry, the electronic components that exceed 70oC will malfunction and damage due to the overheated. The design is used nanosilver as main material in thermo pad because it has high value of thermal conductivity and enables to dissipate heat very efficiently. The advantages of this product are enables to reduce junction temperature of PLCC 20-30%. It also had constant thickness in order to get accurate results. It was a new technology that been applied in electronic industry in order to reduce the temperature of the electronic components.
The Role of Direct Chilling, Retrogression and Reaging Treatment on Mechanical Properties of High Strength Aluminum Alloy
Authors: Naeem Haider T. , Mohammed Kahtan S. , Ahmad Khairel Rafezi , Rahmat Azmi
Published: September 2013

The effect of retrogression and reaging heat treatment on microstructure evolution andmechanical properties of 7075 Al alloy in direct chilling casting process was investigated. The subsequent heat treatment process comprised pre-aging at 120°C for 24 h, retrogression at 180°C for 30 min, and then reaging at 120°C for 24 h. By this three-step process, the mechanical properties of the chilled casted samples were substantially improved. The samples retain their high strength at T6 level. They gave yield strength up to 290 MPa, ultimate tensile strength of 386 MPa and elongation of 5.9%. The average value of multiple Vickers hardness tests results were in the range of 210 Hv. The direct chilling process followed by retrogression and reaging heat treatment yielded casts of fine and uniform microstructure as opposed to the microstructure of samples casted by the conventional process.
The Effects of Extraction Mediums on the Properties of Porous Epoxy Using Natural Rubber Latex as Void Template
Authors: Ishak S.N. , Teh P.L. , Lan Du Ngoc Uy , Yeoh C.K. , Phua J.L.
Published: September 2013

Porous epoxy was fabricated by using natural rubber latex particles as the void template which were extracted after by different types of extraction mediums such of distilled water and toluene under ultrasonic. As expected, the increase in latex content from 0.5, 1.0, 1.5 to 2.0 phr in porous epoxy produced the higher porosities as well as lower dielectric constant property. Furthermore, toluene medium extracted more NR latex particles and produced more porous in epoxy matrix compared to distilled water medium. Therefore, porous epoxy from toluene extraction exhibited better dielectric constant property, which is preferred for electronic packaging application. Besides that, the mechanical properties also showed a reasonable reduction in flexural strength and modulus of the epoxy porous obtained from toluene extraction compared to distilled water extraction.
Effect of Deposition Time on Properties of ZrO2 Coating Prepared Using Electrolytic Method
Authors: Salleh Siti Hawa , Terng Lim Wuh , Derman Mohd Nazree , Omar Mohd Zaidi , Abdullah Salmie Suhana Binti Che
Published: September 2013

AISI 440C martensitic stainless steel is one of the most widely studied engineering materials for its tribological properties. It is capable of attaining the best mechanical properties such as high strength and hardness compared to other martensitic grades. Unfortunately, the corrosion resistance of this 440C steel is the lowest among the stainless group, which results in the precipitation of carbide phases. AISI 440C were coated using electrolytic ZrO2 layer deposition method in ZrO(NO3)2 aqueous solution. In order to preserve the high mechanical properties of this steel, various heat treatment processes applied to the coated samples. After drying and annealing, the ZrO2 coated samples were evaluated using SEM, hardness tests and corrosion tests. Some mud-crack had been indicated in all samples. However, it become more homogeneously on the sample which undergoes longer deposition time. This difference resulted in a significant improved on corrosion resistance of ZrO2 coated sample.
The Effect of Different Sizes "Batu Reput" (Dolomite) as a Filler in SMR L and ENR-50
Authors: Ridhwan J.N.M. , Noimam N.Z. , Mohd Salleh M.A.A. , Sam S.T. , Musa L. , Nik Yahya N.Z.
Published: September 2013

The effects of different sizes of Batu Reput (Dolomite) filler which are smaller size (<63μm) and bigger size (75-150μm) on tensile and morphological properties of Batu Reput (Dolomite) filled SMR L and epoxidized natural rubber (ENR-50) blends were investigated. Results indicated that, the tensile properties, such as tensile strength (TS), elongation at break (Eb) and stress at 100% elongation (M100) of Batu Reput (Dolomite) filled SMR L higher than Batu Reput (Dolomite) filled ENR-50 blends, particularly, at 15 phr of smaller size of Batu Reput (Dolomite). The scanning electron microscopy studies proved, Batu Reput (Dolomite) filled SMR L illustrated a higher Batu Reput (Dolomite) - SMR L matrix interaction compared with Batu Reput (Dolomite) filled ENR-50.
Comparison of Mechanical Properties of Polypropylene/Acrylonitrile Butadiene Rubber/Rice Husk Powder Composites Modified with Silane and Acetic Anhydride Compound
Authors: Ragunathan Santiagoo , Sam S.T. , Noriman N.Z. , Amneera W.A. , Andrew A.M. , Ismail H.
Published: September 2013

Polypropylene (PP)/Acrylonitrile butadiene rubber (NBRr)/rice husk powder (RHP) composites was fabricated with silane and acetic anhydride treatment agent. The in-situ formed RHP filled PP/NBRr composites were prepared by melt mixing technique using Haake internal mixer at 180 °C. The tensile properties of the both treatment methods were invesigated with Instron mechanical analysis. The results indicated that acetic anhydride treatment was found to exhibit better mechanical properties for RHP filled PP/NBRr composites. Good compatibility and stronger interaction between anhydride moieties with PP/NBRr was resulted.
Failure Investigation on Rusty Mesh Strainer of Petrochemical Plant
Authors: Shamsudin Shaiful Rizam , Harun Mohd , Mohd Salleh Mohd Arif Anuar , Yazid Hafizal , Mazlee Mohd Noor
Published: September 2013

The wire material of filter mesh is made of 304 grade stainless steel. The failure to run properly was due to the impact of burst and torn. The client also expects that the failure was due to corrosion problems. A visual inspection on the strainer mesh was found covered by brownish rust layers and some scratches at the damaged area. The rusty wire mesh that was washed with pickling acid showed a clean and smooth surface. Energy dispersive spectroscopy (EDS) examination of the rusty wire mesh surface indicated that it was only normal oxide precipitates. Thus, it's proven that there were no signs of severe corrosion attack on the failed sample. SEM micrographs showed the unidirectional scratch effects exist in the damaged area. The fractography study was found there was a typical ductile structure on the fracture surface of the wire. It is proven that the wire mesh was actually still in good condition and has not experienced any embrittlement problems as if it exposed to any corrosive environment. The root cause of the failure is shown by the effect of scratches in which it is usually caused by a mechanical forceful push by a hard object or in other words, it is caused by human error factor.
Dielectric Properties of Barium Titanate with Different Stoichiometry
Authors: Faris Meor Ahmad , Yeoh Cheow Keat , Idris Mohd Sobri , Teh Pei Leng
Published: September 2013

This paper focused in details about dielectric properties of BT with different stoichiometry. In this research, BT was synthesis by solid state reaction between TiO2 and BaCO3 at constant sintering temperature of 1350 °C. Five different ratio of BT was characterized by using SEM, XRD, and IS. There have production of secondary phase when Ba was excessive. Impedance plot shows the relation between dielectric properties and stoichiometry of BT where the highest value of dielectric properties is comes from sample with Ba/Ti ratio equal of 1:1.