bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Design of Experiment and Genetic Algorithm to Obtain the Optimum Gear Shifting Strategy for a Real Driving Cycles
Authors: Ahmed Aboud , Zhao Chang Lu , Han Kai , Zhang Fu Jun , Wu Feng
Published: November 2012

Design of Experiment statistical method and Genetic Algorithms based optimization method are used to obtain the optimum gear shifting strategy that driver can follow to provide best fuel consumption without affecting drivability characteristics of the vehicle according to certain driving cycle. The study is carried on a Mining Dump Truck YT3621 with 9 forward shifts manual transmission. Three loading conditions, no load, 20 ton and 40 ton have been discussed. The truck powertrain is modeled using GT-Drive, and DOE –Post processing tool of the GT-Suit is used for DOE analysis and Genetic Algorithm optimization. Six different real on road driving cycles are used to study the effect of gear shifting strategy on fuel consumption.
Control System Design and Modeling for Compensation Wheel
Authors: Wang Lei , Ge Sheng Min
Published: November 2012

For the defects exist in recent design method of compensation wheel, the working speed is raised to reduce the mass increment and improve the bearing lubrication. By the means of new thought, a double closed loop controller is proposed which uses high-authority control (HAC) and low-authority control (LAC) to guarantee the speed of response and steady-state error for a good performance. The models of encoder, friction torque and compensation wheel are established in Simulink. Based on the requirement of attitude stability and pointing accuracy of a satellite, the controller parameters are synthesized. In the section of simulation, results reveal that the compensation system has a satisfied performance.
A Route Selection Mechanism for Mobility of Node in Mobile Ad Hoc Network
Authors: Cha Hyun Jong , Kim Jin Mook , Ryou Hwang Bin
Published: November 2012

A mobile ad-hoc network is a method of communication between different nodes (mobile devices) without the use of base stations, which are used in wired networks. In a Mobile ad-hoc network, nodes can play the role of a receiver, sender, or a relay. As movement is flexible in Mobile ad-hoc networks and nodes have limited resources, nodes may join the communication or exit it at any time. Therefore, for Mobile ad-hoc networks, routing techniques - selecting communication routes and maintaining them – is considered important in an environment of constantly changing network topology. To overcome this problem, this paper proposes a reliable routing protocol based on MP-AOMDV, which monitors changes in signal strength not only for GPS signals but reception signals as well. Although MP-AOMDV was researched under the assumption of fixed movement direction and speed, this paper proposes a routing technique that works with changing movement direction or speed of nodes.
Abnormalities Detection of IMU Based on PCA in Motion Monitoring
Authors: Zhou Jing , Su Steven , Guo Ai Huang , Chen Wei Dong
Published: November 2012

Inertial measurement units (IMU) are used as an affordable and effective remote measurement method for health monitoring in body sensor networks (BSNs) based on tracking people’s daily motions and activities. These inertial sensors are mostly micro-electro-mechanical systems with a combination of multi-axis combinations of precision gyroscopes, accelerometers, and magnetometers to sense multiple degrees of freedom (DoF).Unfortunately in the process of motion monitoring actual sensor outputs may contain some abnormalities, which might result in the misinterpretations of activities. In this paper, we use Principal component analysis (PCA) combined with Hotelling’s T2 and SPE statistic to detect abnormal data in the process of motion monitoring with IMU to ensure the reliability and accuracy in application. The simulated results prove this method is effective and feasible.
Pipeline Dehydration Station Centralized Control System
Authors: Geng Wei Dong , Gong Yu , Zhang Li , Pan Chun Lei , Wu Jian De
Published: November 2012

The iron ore concentrate transport is one of an important factor in restricting the mining economic development; pipeline is a good solution with the hydraulic. The Dongchuan pipes are the use of the gravitational potential energy to achieve transporting concentrates by the way of self-flowing drop. The project is highly energy saving demonstration. However, it has a high demand of the control system of the end of the pipe dehydration station running due to the complex topography. Centralized control system given in this paper, having the characteristic of high reliability, operating performance, real-time strong, versatile and high economic benefits. The system realize the intelligent monitoring of the whole plant, all equipment control, the detection signal into the control room, remote control of the bottom pump system on the mountain, all equipment automatically switches to control. The system has a certain generalization.
Three Dimensional GIS Monitoring System of Mineral Pipeline Transporting System
Authors: Geng Wei Dong , Gong Yu , Zhang Li , An Jian , Wu Jian De
Published: November 2012

Designing the three dimensional (3D) GIS software used in monitoring mineral pipeline transporting system. The software can truly show and restore the geography of project and the features of terrain .The operator can not only examine and grasp the true situation of the distribution of pipeline, but also keep watch on the secure running of the pipeline by real-time remote video in the remote control room. The practical application indicates that the pipeline can run safely, stably and efficiently with the monitoring system.
Research on and Design of Assembly Line Monitor and Control System Based on PC
Authors: Gao Tian Yi , Mu Guang Yu , Pan Lan Lan , Xie Zhong Dong
Published: November 2012

A control system is developed based on PC, which could collect real-time data and monitor the equipments state for assembly line. The software platform is C#. The technology of sensors, PLC, computer are integrated, and OPC technology is used based on the idea of configuration software to achieve an automatic monitoring system. The data of PLC can be exchanged through the database system integrated in PC. The complex calculation, friendly man-machine interface are achieved in the system. Through monitoring the equipment and environment on the shop floor on-line, the causes of the problems in automatic assembly line can be accurately analyzed in time to make a quick deal. The result shows that the PC-based monitoring system is easy to control, convenient to operate and low-cost to develop and run.
Modeling of Fatigue Crack Growth under High-Low Sequence Loading
Authors: Yao Zhi Wei , Qiu Bao Xiang , Wang Xiao Gui
Published: November 2012

The fatigue crack growth behavior of one compact tension specimen of 16MnR steel under high-low sequence loading was investigated. The symmetric half finite element model under plane-stress state was used to calculate the elastic-plastic stress-strain responses, in which the Armstrong-Frederick type cyclic plasticity model was implemented as a user material subroutine UMAT of ABAQUS. A recently developed dynamic crack growth model was used to simulate the effects of high loading step on the successive low loading step. The detailed evolution process of the crack closure and cyclic plastic zone within the retardation region of fatigue crack growth was obtained. The extend of the crack closure, the size of cyclic plastic zone and the stress gradient have significant influence on the fatigue crack growth rate. The predicted fatigue crack growth rate is in good agreement with the experimental data.
Design of MDA Based Model Transformation Profile for Model Verification
Authors: Ko Jong Won
Published: November 2012

Validation of existing software design models and transformed target models for the study, mainly checking (Model Checking) with a code-based software designed to define in the abstract syntax tree or on the models generated using refactoring on design models for refinery operations and define how to perform. The problem with these traditional research methods, but the first model, design model for checking the information with the model by defining a formal representation in the form of an abstract syntax tree, as you've shown how to perform validation of UML design model. Additional steps need to define more complex due to a software problem that is not the way to the model suitable for model transformation verification. In this paper, as defined in the MDA based model transformation studies of a graph based mode transformation, and how to perform model transformation verification through improving graph comparison algorithm and model property information.
An Engineering Analysis and Research on Center Frame Structure Using Casting of Vehicle Radar Antenna Pedestal
Authors: Chang Feng Ji , Liu Wei Na , Li Yu Jun , Wu Meng Han , Wu Yu Bin , Tian Xing Zhi
Published: November 2012

According to the usage of vehicle radar antenna pedestal center frame, this article analyzes and compares the structure characteristic of welding and casting. We decide to adopt the casting structure and use special casting material ductile iron QT450-10. And we describe the casting material ductile iron QT450-10. Based on the center frame of using conditions, we analyze the deformation and stress of center frame by the finite element analysis software. The design is in line with the material allowable requirements and to meet the requirements of the system stiffness.
The Method of FMEA and FTA Based on System Fault Behavior Model
Authors: Zhao Guang Yan
Published: November 2012

System fault behavior model is a behavioral model to describe the occurrence and development process of system fault. It can reliaze fault propagation through the description of system normal and fault behavior. The application of system fault behavior model was studied in this paper. The method of FMEA and FTA based on system fault behavior model was brought forward and the process and steps of this method were discussed in detail. Finally, a typical case was analyzed to validate the effectiveness and practicness of this method.
A Novel Data Mining Method on Quality Control within Spinning Process
Authors: Lv Zhi Jun , Xiang Qian , Yang Jian Guo
Published: November 2012

Rough sets theory (RST) is a new data mining method that effectively deals with the problems with inexact, uncertain or vague knowledge in a complex information system. This paper investigates knowledge discovery methods from the textile industrial database, and then presents a RST-based intelligent control model (ICM) for spinning process. In order to analyze the yarn strength when the characteristics of fibers are given, a rule extraction method based on RST is researched. The logical rules extracted from the decision table indicate that the initial strength of fibers is a key factor influencing on the yarn strength. At the same time, the different values combination of the final reduced attributes also obviously influence on the yarn strength in different degree when the certain nominal yarn is being processed. Therefore, RST method can be taken into account for spinners to choose suitable fiber materials in order to ensure the quality and reduce cost.
Concentrated-Leakage Detection by Emulation of Temperature Field
Authors: Wang Xin Jian , Li Ri Yun , Chen Jian Sheng
Published: November 2012

In order to detect the concentrated leakage passages(CLP) more effectively and precisely, the temperature field emulation method of irregularity dam including seepage and leakage is established based on numerical optimization of concentrated leakage passage detection with kinds of boundary conditions. In this model, the effect of lapse rate, radiation from sun and wind speed on temperature field is included. The flow states of underground water determined, the heat transfer characteristics presented and the coupled relation between seepage and temperature distribution constructed, the coupled equations between seepage and heat transfer are set up.
Optimization Design of Injection Molded Parts Based on Mold Flow
Authors: Yang Jun Kai , Xu Yun Jie
Published: November 2012

PC injection molded parts are taken as an example. Mold flow software is used to predict the filling condition of the product, estimate the injection pressure and clamping force required to mold this product and its warpage, and find elements that cause the warpage so as to change the mold structure, reduce warpage and improve the quality of the product.
Nanocrystalline Co82Ni18 Alloy: Synthesis and Magnetic Properties
Authors: Panday Sudhakar , Daniel B.S. Sunder , Jeevanandam P.
Published: November 2012

Nanocrystalline Co82Ni18 alloy was synthesized by polyol reduction of cobalt-nickel hydroxide precursor. X-ray diffraction results indicated the formation of fcc phase alloy and the crystallite size was found to be about 19 nm. Scanning electron microscopy and transmission electron microscopy images showed the morphology of particles close to spheres and stoichiometry of the precursor and the alloy was obtained by the energy dispersive X-ray analysis. Selected area electron diffraction pattern indicated the polycrystalline nature of the alloy particles. The saturation magnetization of the nanocrystalline alloy was about 107 (emu/g) at room temperature and the M-H measurements at 300 K and 5 K indicated that the nanocrystalline alloy exhibits close to superparamagetic behaviour.
Optical Study on Gadolinium Oxide Nanoparticles Synthesized by Hydrothermal Method
Authors: Selvalakshmi T. , Bose Arumugam Chandra
Published: November 2012

Cubic phase gadolinium oxide nanoparticles were prepared by hydrothermal method at various reaction temperatures like 60 °C, 120 °C, 180 °C and 240 °C. X-ray Diffraction (XRD) studies confirmed the formation of cubic phase Gd2O3. The broadening of XRD peak, due to crystallite size was investigated with the aid of gaussian and voigt peak fitting function and its comparisons were also performed. Crystallite size calculated from Scherrer formula for Gd2O3 nanoparticles for various reactions temperatures varies between 21 nm and 39 nm. Thermal analysis of as-prepared sample was done and the decomposition temperature was found to be 433 °C for the formation of Gd2O3. The metal-oxygen band in Fourier Transform Infrared Spectroscopy (FTIR) spectra confirmed the presence of Gd2O3. Band gap studies from Diffuse Reflectance Spectroscopy (DRS) revealed the decrease in band gap with respect to the increase in crystallite size. In Photoluminescence (PL) spectra, a broad ultra violet emission is observed between 320 nm and 400 nm. Irrespective of reaction temperature, Scanning Electron Microscopy (SEM) images reported the formation of nanorods.
Synthesis and Characterization of Ag - Soda Glass Nanocomposites
Authors: Rozra Jyoti , Saini Isha , Aggarwal Sanjeev , Sharma Annu
Published: November 2012

In the present work we have used Physical vapour deposition (PVD) technique followed by thermal annealing to synthesize Ag-soda glass nanocomposite samples. This technique offers a great deal of promise in terms of general simplicity of operation, minimal requirements for sample preparation, ease of adaptation to automated operation, and potential for scale up to production levels of material throughput. Ag-glass nanocomposites were synthesized by deposited Ag on glass slides and the resulting samples were annealed in air at various temperatures from 400 °C to 550 °C for 1 hour. Optical absorption spectrum of the resulting nanocomposites was measured in the range from 190 nm to 900 nm using UV-Visible absorption spectroscopy. The appearance of SPR peak characteristic of Ag nanoparticle formation around 420 nm in optical spectra of annealed samples indicates towards the formation of silver nanoparticles in soda glass. The size of silver nanoparticles has been found to increase with increase in annealing temperatures. Structural properties of resulting nanocomposites were also studied using TEM and FE-SEM alongwith EDAX spectra. Synthesized composites are more conducting than pristine glass and conductivity increases with increase in size of Ag nanoparticles embedded in glass. Possible mechanism for increase in conductivity has been discussed.
Fabrication and Characterization of ZnO Nanowires by Thermal Oxidation Method
Authors: Somvanshi Divya , Jit Satyabrata
Published: November 2012

Fabrication of ZnO nanowires (NWs) by thermal oxidation method has been studied in this work. The ZnO NWs have been grown by oxidation of Zn metal foil under oxygen environment for two typical oxidation durations. We have investigated the behavior of the as-grown ZnO NWs with the change in oxidation duration at particular temperature. The changes in surface morphology and chemical composition with the variation of oxidation duration have been analyzed by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) respectively. From EDS spectra, it is confirmed that Zn metal has completely oxidized into ZnO for higher oxidation duration. In this work, the optimized duration of oxidation for growth of ZnO NWs is found to be ~60 minutes at particular temperature of 600oC. The present method provides a possible mechanism for the growth of ZnO NWs on the p-Si substrates.
A Numerical Study on Heat Conductivity Characterization of Aluminium Filled Polypropylene Composites
Authors: Agrawal Alok , Satapathy Alok
Published: November 2012

A numerical simulation of the heat-transfer process within polypropylene matrix composite filled with micro-sized aluminium particles using Finite Element Method is proposed in this paper. Three-dimensional spheres-in-cube lattice array models are constructed to simulate the microstructure of composite materials with aluminium content ranging from about 1.5 to 42 vol% and the effective thermal conductivities of the composites are estimated. A commercially available finite-element package ANSYS is used for this numerical analysis. The result shows that the effective thermal conductivity (Keff) increases with increase in the volume fraction of the aluminium in the composites. The simulated values are compared with calculated Keff values obtained from other established correlations such as Rule-of-Mixture (ROM), Maxwell’s model and with published experimental results. This study reveals that the incorporation of aluminium particles results in enhancement of thermal conductivity of polypropylene thereby increasing its heat transportation capability. It is found that with incorporation of about 42 vol% of 100 micron sized aluminium particles thermal conductivity of the composite increases from 0.239 W/m-K to 0.875 W/m-K. This study also shows that the effect of particle size with same volume percentage on thermal conductivity is marginal.
Mythology Merges with Technology for Majestic Production of Silver Nanoparticles: Rudraksha Enabled
Authors: Dwivedi Poushpi , Narvi S.S. , Tewari R.P.
Published: November 2012

In this nanoregime attempts to bring forth nanoparticles and nanomaterials are myriads, with there interesting and demanding applications in almost every field. Today the field of nanoscience has bloomed with the confluence of nanotechnology with material science, biology, biotechnology and medicine and the need for nanotechnology will only increase as miniaturization becomes extremely important in various arrays of life. Since time immemorial silver nanoparticles have been extensively used for hygienic and healing purposes, and even until most recently, it has indispensible vital role especially in the biomedical arena. Thus in an attempt to generate silver nanoparticles employing green, environmentally benign route, we have designed to converge mythology with technology, with the mystical production of silver nanoparticles, enabled by the blueberry beads of the plant Elaeocarpus granitrus Roxb., the Rudraksha. This non-degradable bead does not disintegrate, but retains the potentiality, even after unlimited production of silver nanoparticles, assisting infinite times. The extremely cost-efficient nanoparticles thus developed in a superiorly efficient manner were characterized through different techniques; like UV/visible spectroscopy, PL spectroscopy, transmission electron microscopy, energy dispersive X-ray analysis and nanoparticle size analysis.
Synthesis, Characterization and Antibacterial Activity of ZnO Nanoparticles of Different Morphology
Authors: Sharma Sulaxna , Naik Devendra , Agarwala Vijaya
Published: November 2012

Nanometric zinc oxide was prepared by sol-gel method using two different capping agents e.g., ethylene diamine (EDA) and citric acid (CAM) in different solvents. Nanorods of ZnO was prepared by sol-gel method using zinc nitrate hexahydrate (1M). The as-synthesized samples were characterized using XRD, FESEM-EDAX, TG/DTA techniques. FESEM micrographs suggest that the formation of nanorods of ZnO takes place for EDA and CAM in MeOH after calcination at 150 °C and 170 °C, respectively for 12h. The antibacterial activity tests (also known as plus-minus tests) were done by allowing bacteria to grow normally in laboratory conditions, and also by subjecting to ZnO nanoparticles in the powder form. On comparison of the above two Petri plates, the presence of a zone of inhibition indicates the antibacterial nature, which would have not existed if the bacteria did not experience any adverse effects by the presence of the ZnO nanorods. In the present study, the activity tested against Escherichia coli ATCC 25922 (gram-negative) Micrococcus leuteus and Bacillus subtilis (gram-positive) the results suggest the selective activity of the nanoparticles against these species.
Influence of Melting of Transition Metal Oxides on the Morphology of Carbon Nanostructures
Authors: Jana Malay , Sil Anjan , Ray Subrata
Published: November 2012

Different types of carbon nanostructure materials have been grown on nano-sized transition metal oxide based catalyst particles by catalytic chemical vapour deposition. The present investigation reveals an important role of melting or surface melting of oxide catalysts for the growth of carbon nanostructure materials. In the reducing environment prevailing during the growth of nanostructures, oxide catalysts are reduced to metals, which may act as a template for the growth of carbon nanostructure materials. Flow rate of acetylene gas is crucial in catalyzing the growth, as high flow rate of acetylene may cover the catalyst particles with a layer of decomposed carbon, rendering the particles incapable of playing the role of catalyst. The size of the catalyst and the extent of melting, determined primarily by the extent of doping, are important in deciding whether the conditions are favourable for the growth of multi walled carbon nanotube, nanofiber or other nanostructures. Smaller particle size and low doping level favour the growth of multi walled carbon nanotube while growth of nanofiber is commonly observed with larger particles and higher doping level. The size (i.e. diameter) of the nanostructures growing around the catalyst is proportional to the particle size of the catalyst.
Analytical Prediction of Thermal Behaviour during Cooling of a Hot Steel Strip
Authors: Barman Shambhunath , Barman Nilkanta , Mukhopadhyay Achintya , Sen Swarnendu
Published: November 2012

The present work predicts the thermal behavior of a hot steel strip analytically where the strip is cooled with water spray. The cooling process is represented by a steady 2-D energy conservation equation. An effective heat transfer coefficient is considered to represent the water spray and the strip surface heat interaction. The solution considers the separation of variables method with appropriate boundary conditions. Finally, the work involves quick evolution of temperature variation in the strip. It is found that the present analytical prediction agrees well with numerical prediction.
Dielectric Behavior and Impedance Spectroscopy of Ba1-xBixTi1-xFexO3 System
Authors: Kumar Arvind , Dwivedi R.K , Pal Vijayeta
Published: November 2012

Studies on the analysis of impedance spectroscopy of polycrystalline samples with compositions x ≤ 0.20 in the system Ba1-xBixTi1-xFexO3 are made. For this all the samples are prepared using solid state ceramic route. Preliminary X-ray diffraction patterns showed single phase formation of all compositions with tetragonal symmetry for x = 0.02 and cubic symmetry for compositions with x ≥ 0.10. For composition with x = 0.02, the dielectric anomaly at ~100 °C indicates paraelectric to ferroelectric transition. Impedance spectroscopic studies over the temperature range 25 °C to 180 °C have shown the presence of both bulk and grain boundary effects. The bulk conductivity has exhibited Arrehenius type thermally activated hopping process which is supported by ac conductivity behavior as a function of frequency.
Investigation on Glasses in Strontium Zinc Borosilicate System as Sealants for Solid Oxide Fuel Cell
Authors: Tiwari Babita , Gadkari S.C. , Kothiyal G.P.
Published: November 2012

Glasses in the SrO-ZnO-B2O3-SiO2 (SZBS) system with different additives like V2O5, Cr2O3, TiO2, and Al2O3 have been prepared by melt-quench method. Glasses were subjected to controlled heat treatment for conversion into glass-ceramics. Investigated glasses and glass-ceramics have thermal expansion coefficients (TEC) in the range of 95-120 x 10-7/oC (30-600 oC) which closely match with TEC of other SOFC components. XRD indicates the crystallization of Sr2ZnSi2O7 solid-solution phase in glasses upon heat treatment. Structural studies revealed that mainly Q1 and Q2 silicate structural units are present in the glass network and B2O3 enters in the network as triangular borate (BO3) structural units. Only small fraction of B2O3 enters as tetragonal borate (BO4) structural units at higher concentration of B2O3. Glass network depolymerizes with the addition of additives and concentration of Q1 units increases at the expense of Q2 units. Small addition of V2O5 in SZBS glass is beneficial for increasing TEC and achieving better flowability at lower sealing temperature. Studied SZBS glasses also show good bonding with Crofer-22-APU. Elemental line scans indicate that interdiffusion of Fe, Cr, Sr and Si across interface is responsible for good bonding with Crofer-22-APU. To show suitability of material for high temperature sealing, seals have been prepared and tested for vacuum integrity at 850oC for 500h.
Spectroscopic and Electrical Studies of Ferrous Sulphate Doped Polyaniline
Authors: Kumar Anand , Vazid Ali , Kumar Sushil
Published: November 2012

Polyaniline (PANI) has been synthesized by chemical oxidative polymerization technique with potassium dichromate oxidant in aqueous hydrochloric acid medium. After polymerization, the polymer so prepared is doped with ferrous sulphate, a transition metal salt, with tetrahydrofuran and water as solvents. The undoped/doped samples were characterized by various techniques such as UV-visible spectroscopy, FTIR spectroscopy, X-ray diffraction and dc conductivity measurements. UV-visible absorption studies revealed the presence of cation/polaron transitions and the presence of direct optical transitions. FTIR studies provide information regarding structural changes in the backbone of PANI with doping concentration. X-ray diffraction patterns of powdered polymer composites showed amorphous nature as mostly conducting polymers exhibit. The dc conductivity of PANI-ferrous sulphate composites were measured by two probe method in pellet form at room temperature (300 K) and found to increase with temperature showing the semiconductor behavior of synthesized polymer composites
Synthesis, Characterization and Electrical Conductivity Measurements of Polypyrrole/ Montmorillonite Nanocomposites
Authors: Parmar Priyanka , Agrawal Pragyesh , Bajpai Rakesh
Published: November 2012

The effects of varying weight percentage ratio of polypyrrole /montmorillonite clay (PPy/MMT) on the DC and AC conductivities are reported. The PPy/MMT nanocomposites were characterized by using the X-ray diffraction, FTIR and SEM techniques. The presence of sharp peaks is observed in the XRD spectra of PPy/MMT composites which suggest the development of more polycrystalline structure. The sharp peaks observed in the XRD spectra of for pure MMT clay is found to be shifting to lower angle with decreasing MMT clay percentages in the PPy. The slight shifting of the peaks confirms that the PPy chains are intercalating into the MMT clay layers. The interplanar spacing (d-spacing) for various composites has been calculated and reported. The successful incorporation of montmorillonite clay in the prepared PPy/MMT clay composites is confirmed by the FTIR spectra. The SEM micrographs exhibit a dense and more ordered structure of PPy/MMT composites. The DC conductivity is initially found to increase in the range 0 to 1% of MMT and thereby, it decreases upto 10 % MMT. The increasing conductivity is again observed from 10 to 15 % of MMT beyond which the conductivity decreases upto 25% of MMT. The AC conductivity of the PPy/MMT nanocompsites has also been measured in the frequency range of 100 Hz to 1 MHz. The AC conductivity is found to be almost constant upto 104 Hz and it is found to rise rapidly thereafter. The variation of conductivity has been explained on the basis of formation of layered structures.
Ultrasonic Lamb Wave Based Crack Growth Prediction for Estimation of Strain Energy Release Rate
Authors: Ramadas Chennamsetti , Hood Avinash , Balasubramaniam Krishnan , Joshi Makarand
Published: November 2012

A technique is proposed to predict crack growth for the estimation of Strain Energy Release Rate (SERR) of Double Cantilever Beam (DCB) bi-metallic specimen, employing ultrasonic Lamb waves. Techniques based on the Time-of-Flight (ToF) of the Turning Lamb Mode (TLM) and Direct Lamb Mode (DLM) explored to determine the crack growth. Sensitivity analysis revealed that the Lamb mode with low velocity is more sensitive to crack growth than that of the high velocity Lamb mode.
Conductivity Measurement of Calcia Stabilized Zirconia Prepared by Mechanical Route
Authors: Prasad Raja Ram , Yadav K.L. , Puri Devendra , Daniel B.S. Sunder
Published: November 2012

Calcia-stabilized zirconia (CSZ) sensor elements of 8 and 16 mol% was synthesized by mixing appropriate amounts of Calcia and Zirconia using in agate mortar and pestle followed by sintering at 1500°C for 3 hours. The electrical conductivity of the stabilized zirconia was measured at different temperature using the two probe impedance analyzer in the temperature range 150°C to 500°C. It was found that the calcia influences the grain boundary thickness. The conductivity is discussed in terms of the ionic vacancies in the bulk due to calcium ion substitution and the available grain boundary path.
Structural, Optical and Ferroelectric Properties of BiCoO3:BiFeO3 Composite Films
Authors: Annapureddy V. , Pathak N.P. , Nath Rabinder
Published: November 2012

Multiferroic materials, which simultaneously exhibit ferroelectricity and ferromagnetism, have recently stimulated a sharply increasing number of research activities for their scientific interest and significant technological promise in the novel multifunctional devices. Natural multiferroic single phase compounds are rare, and their magnetoelectric response are relatively weak at room temperature. In contrast, multiferroic composites improve the magnetoelectric coupling at room temperature which can have potential applications in data storage, sensors, spintronics and filters. In view of this, Multiferroic BiFeO3 –BiCoO3 (BF-BC) composite thin films have been prepared by the spray pyrolysis method, where (110) - oriented texture was obtained. X-ray diffraction analyses confirmed that BF-BC composite films were highly (110) textured. The AFM images show that the films were uniform, dance and of nearly spherical shape nanoparticle with size of 18 nm. The (110) - texture BF-BC composite films exhibits improvement in remanent polarization and coercive field with very low leakage current. The optical properties of the composite films have been studied and correlated with their structural parameters.
Ground State Electronic and Magnetic Properties of LaCrO3 System
Authors: Tiwari Brajesh , Rao M.S. Ramachandra , Dixit Ambesh
Published: November 2012

First principle calculations are carried out to investigate the ground state electronic and magnetic properties of G-type antiferromagnetic (AFM) LaCrO3 compound in orthorhombic phase. The orthorhombic LaCrO3, a distorted GdFeO3 – type perovskite exhibits AFM transition at ~290 K. Additionally; this system shows weak ferromagnetism at room temperature, in conjugation with its semiconducting properties. In this paper, we will discuss the onset of weak ferromagnetism and electronic properties of LaCrO3, implementing generalized gradient approximation for exchange correlation potential. We present results for electronic structure and density of states, including the effect of onsite Coulomb interaction and non-collinear arrangement of Cr3+ magnetic ions in G-type AFM geometry.
Optimum Stacking Sequence Design of Composite Sandwich Panel Using Genetic Algorithms
Authors: Bir Amarpreet S. , Chen Hsin Piao , Chen Hsun Hu
Published: November 2012

In the present study, both critical buckling load maximization and face-sheet laminate thickness minimization problems for the composite sandwich panel, subjected to bi-axial compressive loading under various imposed constraints have been investigated using genetic algorithms. In the previously published work, the optimization of simple composite laminate panels with only even number of laminae has been considered [1, 3]. The present work allows the optimization of a composite sandwich panel with both even and odd number of laminae in the face-sheet laminates. Also, the effects of the bending-twisting coupling terms (D16 and D26) in bending stiffness matrix which were neglected in the previous studies [1, 2, 3], are considered in the present work for exact solutions. In addition effect of both balanced and unbalanced face-sheet laminates on the optimum solutions have also been investigated, whereas only balanced laminates were considered in the previous studies [1, 2, 3].
Mechanical and Dielectric Properties of PTSL FRP Composites
Authors: Srinivasababu Nadendla , Kumar J. Suresh , Reddy K. Vijaya Kumar
Published: November 2012

Utilization of natural fibers for making composites and employ them in various structural applications due to superior specific properties drawn the attention of researchers in the present scenario. In the present research a new natural fiber i.e. Palm Tree Sprout Leaf (PTSL) is introduced, and is extracted by a novel technique called pure splitting method. Untreated and chemically treated palm tree sprout leaf fiber are reinforced into the polyester matrix for fabricating composites and are tested for determining their mechanical and dielectric properties as per ASTM procedures. Morphological characterization of fiber is also done using Scanning Electron Microscope. Tensile strength and modulus, flexural strength of chemically treated PTSL fiber reinforced polyester composites exhibited a reasonable improvement when compared with the untreated fiber reinforced polyester (FRP) composites. Flexural modulus of PTSL FRP composites is more when compared with chemically treated FRP composites at all volume fractions of fiber. Impact strength of PTSL FRP composites clearly increased with increase in fiber volume fraction. The reasonable values of dielectric strength at various fiber volume fractions exhibited by PTSL FRP composites will give an opportunity for designer in choosing light weight insulating material.
Properties and Characteristics of Sisal Fibre Reinforced Composite
Authors: Sharma Ankita , Suresh S. , Dubey Amit
Published: November 2012

Using the pin on disc wear testing machine the wear characteristics of sisal fibre composite of different content were studied and alignment of fibres in polymer composite were known by scanning electron microscopy. It was observed that when there was no fibre content, the wear was ~25 micron but when the fibre content made 10% to the polymer, the wear increased upto 100 micron and its increased 125 micron at 20% fibre content, after this there is sharp decrease in wear when the sisal fibre content was increased up to 40% and its again reached to 25 micron when the fibre content was increased up to 60% and again after increasing the fibre content 80% the wear gradually increased to 175 micron. Thus to have less wear the fibre content should be 60% in composite.
Influence of Casting Process Parameters on Surface Roughness in Hot-Chamber Die Casting of AZ91D
Authors: Jarfors Anders E.W.
Published: November 2012

Cast magnesium AZ91D, used for cases, covers and housings, for consumer electronics faces increased requirements on aesthetically pleasing surfaces. The casting conditions have strong effect on as-cast surface roughness for thin-walled castings. This is currently not well understood. In the current study surface roughness was measured parallel and perpendicular to the filling direction and on both sides on straight flat thin speci¬men. The parameters studied were First and Second phase injection speed, Cooling time, and Melt temperature. The Fix and Moving side die tempera¬tures were varied, with the fix side was kept hotter. A D-Optimal experimental design was used resulting in 31 different settings. The re¬sults showed that roughness was decreased by mini¬mizing the temperature difference between the two die halves, increasing cooling time and first phase injection speed. Increasing the second phase injection speed increased roughness.
A Study of the Effect of Extrusion Parameters on the Properties of Extruded Zr-2.5Nb Pressure Tubes
Authors: Keskar Nachiket , Raizada Vikrant , Kumar Vaibhaw , Jha Sanjay Kumar , Srivastava Dinesh , Dey Gautam Kumar , Saibaba Nudurupati
Published: November 2012

The hot extrusion of Zr-2.5Nb alloy has been simulated using an FEM based software and validated by the experimental measurements during real extrusion process. The flow stress data for Zr-2.5Nb alloy at different temperatures, strain and strain rates were generated by hot compression testing on Gleeble Machine. The flow stress data, obtained both below β transus temperature in two phase α+β region as well as above β transus temperature in β phase region, were directly used in the FEM simulation of extrusion process, eliminating the need for any assumptions regarding material plastic flow law. Two important extrusion parameters, viz. included die angle and reduction ratio, were varied and for each set of conditions, temperature, strain and strain rate at different nodal points of the tube at different stages of extrusion were calculated. The extrusion parameters were optimized to obtain minimum variation in the force, temperature, strain and strain rate in the extruded product. A fair agreement has been found between the measured values of the applied ram force and the temperature profile at the die landing area in a 3780 ton horizontal extrusion press and those obtained through simulations. The effect of the friction and heat transfer coefficient between the die chamber and work piece was also investigated in this study.
Microstructural Studies of Al 5083 Alloy Deformed through Cryorolling
Authors: Singh Dharmendra , Nageswararao Palukuri , Jayaganthan R.
Published: November 2012

In the present work to investigate the effect of rolling at very low temperature on microstructure of Al 5083 alloy, it was subjected to rolling at room temperature and immediate quenching at liquid nitrogen temperature up to different strain levels. The microstructure of deformed material has been studied using Electron back scattered diffraction (EBSD) and Transmission electron microscopy (TEM) techniques. A homogeneous ultrafine grained microstructure of an average size of 300 nm with well defined grain boundaries could be achieved with an effective rolling strain of only 2.3 followed by short annealing at 300 °C for 6 min. The effect of second phase particles on grain refinement at different stains is discussed. It was observed that increased dislocation density due to effective suppression of dynamic recovery by immediate quenching in liquid nitrogen temperature after each successive rolling passes leads to increased stored energy which further leads to formation of homogeneous ultrafine grained microstructure after short annealing subsequently.
Influences of Temperature of Thermo Mechanical Working on Hardness of Titanium Alloy
Authors: Kumar Anoop , Balasunder Balasunder , Raghu T. , Rajesham S.
Published: November 2012

High specific strength metals with high formability are paramount requirement for maximizing productivity of structural components, aircraft panels & engine components in Automotive & aerospace industry. The material must be suitably processed for better strength & more formability. The formability depends upon several factors one of which is grain size. Finer the grain size better is the formability. In the present study the influence of temperature of thermo-mechanical treatment (TMT) on the microstructure of titanium ally Titan 31 in order to identify suitable TMT to refine the grain size has been investigated.The material was subjected to hot rolling at different temperatures in the range 800°C -900°C. Subsequently the material was subjected to annealing as well as normalizing heat treatments. Grain size and hardness measurements were carried out to identify suitable TMT. The study revealed that rolling at 800°C followed by annealing at the same temperature resulted finer grain size and low hardness that are conducive for better formability.
Effect of Cold Rolling on the Mechanical Properties of Spray Cast Al-6Si-20Pb Alloy
Authors: Mittal Rashmi , Singh Devendra
Published: November 2012

Porosity, hardness and microstructural studies of cold rolled spray cast Al-6Si-20Pb alloy for different percentage of thickness reduction were conducted from top to bottom and from centre to periphery of the deposit. Porosity was found to decrease and hardness was found to increase with the increase in percentage of thickness reduction. Aluminum grains were observed to become coarser with the increase in percentage of thickness reduction.
Mechanical and Microstructural Characterization of 8 mm Thick Samples of SS 316L by CO2 Laser Welding
Authors: Kumar B. Ramesh , Chauhan N. , Raole P.M.
Published: November 2012

Laser beam welding offers various advantages over the other conventional weld processes. In fusion reactor, some critical components with high weld quality are proposed to be fabricated with Laser beam welding. The present paper reports the mechanical properties and micro structural characterization of 8 mm thick SS 316L samples fabricated with high power CO2 Laser welding system. The process parameters of 3.5 kW and speed of 600 mm/min with Argon shielding gas are used. The Laser welded samples are subjected to non destructive testing with X-ray radiography and ultrasonic tests. The welded samples tested have indicated good quality joints with full penetration and no significant porosity and cracks. Further, the samples are subjected to standard mechanical tests namely tensile properties test (UTS), bend test and Impact Fracture test. The Laser weld joints produced better tensile properties as compared to the base metal. In addition, Vickers hardness tests and optical microstructure are studied for the base metal (BM), Heat Affected Zone (HAZ) and weld zone(WZ).
Effect of Post Weld Heat Treatment on Mechanical Properties and Microstructure of Nickel Based Super Alloy Welds
Authors: Agilan M. , Venkateswaran T. , Sivakumar D. , Pant Bhanu
Published: November 2012

In the present paper, Haynes 214 plate of 7mm thick was welded by Gas tungsten arc welding (GTAW) in two passes. The welded plates were subjected to post-weld heat treatment such as direct aging (DA) and solution treatment + aging (STA). The aging cycle was optimized using hardness by generating isothermal aging curve. The weld tensile properties, hardness test, microscopic analysis and fractographic studies were carried out in as-welded condition and at two different post-weld heat treatment conditions. The results show a significant increase in both yield and tensile strength after post weld heat treatment.
Natural Frequencies and Mode Shapes of Laminated Composite Skew Hypar Shells with Complicated Boundary Conditions Using Finite Element Method
Authors: Kumar Ajay , Bhargava Pradeep , Chakrabarti Anupam
Published: November 2012

In the present investigation, free vibration behaviour is studied for the laminated composite skew hypar shells having twist radius of curvature. A higher-order shear deformation theory is employed in the C0 finite element formulation. Higher-order terms in the Taylor’s series expansion are used to represent the higher-order transverse cross sectional deformation modes. The formulation includes Sanders’ approximation for doubly curved shells considering the effect of transverse shear. The structural system is considered to be undamped. The correctness of the formulation is established by comparing the present results of problems with those available in the published literature. The effects of different parameters are studied on the free vibration aspects of laminated composite skew hypar shells. Effect of cross curvature is included in the formulation. The C0 finite element formulation has been done quite efficiently to overcome the problem of C1 continuity associated with the HSDT. The isoparametric FE used in the present model consists of nine nodes with seven nodal unknowns per node. Since there is no result available in the literature based on HSDT on the problem of free vibration of laminated composite skew hypar shells, new results are presented by varying geometry, boundary conditions, ply orientations and skew angles which will serve as benchmark for future researchers.
Optimization of Process Parameters for Friction Welding of Bimetallic Welds
Authors: Chhibber Rahul , Singla Yogesh Kumar , Dutta Bijan Kumar
Published: November 2012

Bimetallic welds made between ferritic steels and austenitic stainless steels are conventionally fabricated using arc welding procedures such as Tungsten Inert Gas, Metal Inert Gas, Shielded Metal Arc Welding and Submerged Arc Welding. However friction welding provides a new and unique solid state approach for joining many similar and dissimilar materials, which may not be possible to join by other welding techniques available without adding any external filler metal. This approach is mostly used in joining of dissimilar materials. The reason for increased utility being the absence of any external filler material which may otherwise add to the heterogeneity of the weld structure. In this paper, the fabrication and effect of friction welding parameters on mechanical-micro structural changes of bimetallic weld joints has been discussed. An attempt has also been made to relate the effect of friction welding parameters on the peak temperature values taken near faying surface and micro hardness changes measured in various zones of weld.