bluuebunny/crossref_metadata_2025 huggingface dataset:
Tool Design and Speed Parameters Effects on Microstructure and Tensile Strength of Friction Stir Welding (FSW) 5052 Al Alloys
Authors: Roudini Ghodratollah , Shiri Sajad Gholami , Rahvard Masoud Mohammadi
Published: October 2011

there are some parameters in friction stir welding (FSW) technique such as tool design, tool rotation speed and tool travel which can be controlled in a precise manner thus controlling the energy input into the system. In this study the effects of these parameters were investigated on microstructure and tensile strength of 5052 aluminum alloy. Roll sheets of this alloy were welded by FSW method at different rotation speeds (400, 800, 1600 and 2500 rpm), welding speeds (50 and 100 mm/min) and tools shoulder diameters (14 and 20 mm). The microstructure results showed that the stir zone (SZ) and thermo-mechanically affected zone (TMAZ) had dynamically recrystallized and recovered respectively. Also the tensile strength of samples welded at tool rotation speeds of 400 and 800 rpm, travel speed 50 mm/min and tools shoulder diameter of 20 mm is similar to that of base metal. The tool rotation speeds of 400 rpm have a good welding ability with higher travel speed and lower tools shoulder diameter.
Prediction of Weld Bead Dilution in GMAW Process Using Fuzzy Logic
Authors: Aghakhani Masood , Jalilian Maziar Mahdipour , Karami Alimohammad
Published: October 2011

Gas metal arc welding is one of the most important arc welding processes used in manufacturing and repair. In this process selecting appropriate values for process variables is essential in order to decide upon metal transfer and subsequently control the heat input into the workpiece from which reliable predictions could be made about the metallurgical, mechanical properties and performance of the welded joints. In this paper, the welding dilution in gas metal arc welding of ST37 steel has been predicted by fuzzy logic. A five level five factor rotatable central composite design was used to collect the welding data and the weld dilution was modeled as a function of wire feed rate, welding voltage, nozzle-to-plate distance, welding speed and gas flow rate.
Feature Selection of Acoustic Emission Signal for the Slow-Speed and Heavy-Load Equipment
Authors: Li Min , Yang Jian Hong
Published: October 2011

Selecting feature in slow-speed and heavy-load equipments has always been a difficult problem. A new feature selection method based on Laplacian Score is used to Acoustic Emission signal. The more capable of describing the sample clustering property, the more important the selected feature is. The method is a ‘filter’ and unsupervised feature selection method which is just dependent on the space distribution of the sample instead of classifier. Therefore, the method enjoys a simple algorithm and low complexity. The effectiveness of the method is verified by the AE datasets from the bearings of a blast furnace’s belt conveyor.
Study on Intelligent Control System of Mechanical Press
Authors: Yang Han , Zhang Xiang Hong
Published: October 2011

In view of digitized heavy-duty mechanical driving technology of alternating current servo machine from the connection between innovative and high technology and conventional mechanical technology, we regard it as the main drive of mechanical press machine, which can improve greatly the performance and intelligent level of press machine. The thesis studies the control system of servo spiral coining machine. We design the hardware of control system based on the scheme about “PC+moving controller”, take GT 200-SV moving controller as upper control unit, alternating current servo driver and special alternating current servo electrical machinery as actuating element to constitute full-closed loop control system. On the basis of it, we choose Visual C++ 6.0 as development tool on the software, adopt modularized and object-oriented design procedures to design control system software.
Study of Laminar Horseshoe Vortex Using Particle Image Velocimetry
Authors: Oo Zaw Zaw , Yamin Muhammad Younis , Zhang Hua , Zaka Muhammad , Hu Bo
Published: October 2011

—This study investigates the upstream of the juncture flows generated by the circular cross section cylindrical body mounted on a flat plate using PIV (Particle Image Velocimetry) technique. The flow structure of laminar horseshoe vortex and a topological insight into the flow pattern of the vortex system were observed. Vortex structures for ReD (Diameter Reynolds number) 1600, 2000, 2400 and 3500 are predicted and discussed in detail. Experiments were conducted to investigate the structure of steady and periodic horseshoe vortex, the effect of Diameter Reynolds number, location of horseshoe vortex core and its variation with the change in Diameter Reynolds number and the location and nature of the saddle point located most upstream of the leading edge of the cylinder. The results revealed that (a) two different flow regimes were observed corresponding to four Reynolds number ranges; (b) the upstream vortex systems approach closer to the cylinder whereas the distance of saddle point located upstream of the leading edge of the cylinder moves away from the wall when the Reynolds number increases.
Numerical Investigation of Droplets Breakup in a Microfluidic T-Junction
Authors: Bedram Ahmad , Moosavi Ali
Published: October 2011

A Volume of Fluid (VOF) method is used to study the breakup of droplets in T-junction geometries. Symmetric T-junctions, which are used to produce equal size droplets and have many applications in pharmacy and chemical industries, are considered. Two important factors namely "breakup time" and "breakup length" that can improve the performance of these systems have been introduced. In addition a novel system which consists of an asymmetric T-junction is proposed to produce unequal size droplets. The effects of the channel width ratio and the capillary number on the size and length of the generated droplets and also the time of the generation have been studied and discussed. For simulation the problem, a VOF method used and for verifying the accuracy of the simulation the results compared with two analytical researches and a good agreement was found. The results indicate for the systems that generate equal size droplets, in a specific Capillary number (in our case 0.02) the performance of the system is in its optimum condition. Also for the systems that generate unequal size droplets, in large capillary numbers a wider range of droplets with different sizes can be produced.
Rotation Invariance for Spatial Dispersion Property of the Elastic Constants
Authors: Wang Hong Li , Liu Yan Hui
Published: October 2011

In this paper, invariance under rotation for the first-order and second-order spatial dispersion properties of the elastic constants was researched based on group theory. Softwares for calculating and judging invariance under arbitrary rotation of various order spatial dispersion tensors of the elastic constants were programmed by means of Mat lab. With the help of the softwares which we programmed, the general forms of the first-order and second-order spatial dispersion tensors of the elastic constants which belong to the group SO (2) were got, and it is judged that the above tensors of crystals or quasicrystals which have some degree axis of rotation had invariance under arbitrary rotation about the corresponding axes of rotation. The results were of importance to theoretical and experimental research for higher order spatial dispersion effects of the elastic constants.
Modeling and Simulation of VCSEL’s Turn-on Delay Based on Rate-Equations
Authors: Shi Xin Zhi , Qi Chang , Wang Gao Feng , Hu Ji Cheng , Liu Feng
Published: October 2011

Vertical-Cavity Surface-Emitting Lasers (VCSELs) are a new generation of semiconductor lasers that have many advantages. In this paper, we present a comprehensive circuit-level VCSEL model that addresses the spatial and thermal behavior of VCSELs including turn on delay based on the rate equations without sacrificing the numerical efficiency demanded by the circuit-level simulation of optoelectronic systems. It is implemented into SPICE-like simulators to simulate the dc, ac and transient features (including turn-on delay and turn-off effect) of VCSELs. The simulated results exhibit good agreements with references.
Three-Dimensional Numerical Simulation and Experimental Study of Severe Plastic Deformation of AZ31 Magnesium Alloy
Authors: Xu Shu Bo , Ren Guo Cheng , Jing Cai Nian , Zhao Zhong Kui , Sun Ke Ke
Published: October 2011

Grain size refinement by using equal channel angular Extrusion (ECAE) is an effective way to improve workability and strength of the magnesium alloys. Round workpieces of ECAE processes for AZ31 magnesium alloy are investigated by using numerical simulations and experimental studies in this paper. The processing of ECAE is simulated in order to study the influence of the processing on the deformation behavior of the workpiece and extruding load. The variation trends of the effective strain distributions in the workpiece are changed little for different cross-section. Punch load for extrusion is the major factor to be considered while designing a sound ECAE die. The deformation mechanism of ECAE for grain refinement is obtained. In addition, the experimental finally workpieces shapes and extruding load results are also consistent with FE analysis results.
Stability and Bifurcation Analysis in a Food Chain Model with Delay
Authors: Li Zhang
Published: October 2011

In this paper, we investigate a delayed three-species food chain model. The existence and stability of equilibria are obtained. A explicit algorithm for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form and the center manifold theory.
A New Method for OLED Optical Output Simulation
Authors: Xu Yan Mei , Liu Chong
Published: October 2011

In the paper a new method is presented to simulate the course of light output from organic light emitting device. The method uses optical transmission matrix to deal with multiple layers. To confirm the validity of our theories, a comparison of the theoretic analysis with testing results is given. The calculated curve consistented with the experimental value. By this methoed the Commission Internationale de L'Eclairage （CIE） coordinates of device were simulated. By adjusting the thickness of each layer in organic light emission diode (OLED) we obtained different CIE coordinates. When thickness becomes thicker the CIEX becomes bigger on the other hand CIEY become smaller.
Imperialist Competitive Algorithm for Multiobjective Optimization of Ellipsoidal Head of Pressure Vessel
Authors: Abdi Behzad , Mozafari Hamid , Amran Ayob , Kohandel Roya
Published: October 2011

This work devoted to an ellipsoidal head of pressure vessel under internal pressure load. The analysis is aimed at finding an optimum weight of ellipsoidal head of pressure vessel due to maximum working pressure that ensures its full charge with stresses by using imperialist competitive algorithm and genetic algorithm. In head of pressure vessel the region of its joint with the cylindrical shell is loaded with shear force and bending moments. The load causes high bending stresses in the region of the joint. Therefore, imperialist competitive algorithm was used here to find the optimum shape of a head with minimum weight and maximum working pressure which the shear force and the bending moment moved toward zero. Two different size ellipsoidal head examples are selected and studied. The imperialist competitive algorithm results are compared with the genetic algorithm results.
Study of Heat Affected Zone (HAZ) in Gas Metal Arc Welding (GMAW/MIG) Process
Authors: Moarrefzadeh Ali
Published: October 2011

In this paper, the Gas Metal Arc Welding (GMAW) process is studied and temperature field is gained in this process. Thermal effects of Gas Metal Arc (GMA) and temperature field from it on workpiece (copper) and shielding gas type, is the main key of process optimization for GMAW. Energy source properties of GMA strongly depend on physical property of a shielding gas. In this paper, carbon dioxide (CO2) was used as an alternative gas for its low cost. The basic energy source properties of CO2 GMA were numerically predicted ignoring the oxidation of the electrodes. It was predicted that CO2 GMA would have excellent energy source properties comparable to that of He, Ar GMA. The numerical results show the time-dependant distributions of arc pressure, current density, and heat transfer at the workpiece surface are different from presumed Gaussian distributions in previous models.
Prediction of Laminar to Turbulent Flow over a Sweptback Wing
Authors: Arumugam Sakthivel , Durairaj Shanmugasundaram
Published: October 2011

The Prediction of Laminar-Turbulent flow over wings and airfoils is necessary for low-Reynolds number airflows. The Prediction of onset of transition based on linear and Parabolized Stability Equations (PSE) using en method is reviewed and factors that influence the choice of approach are discussed. Comparison between prediction of linear and parabolized stability equation are given for a range of flow conditions on an Infinite sweptback wing.
Free Vibration Analysis of a Fiber Reinforced Mindlin Plate by Using Ritz Method
Authors: Hashemi S.H. Hosseini , Fazeli S.
Published: October 2011

In this paper the free vibration analysis of a fiber reinforced mindlin plate is presented.energy method based on the ritz method is used to obtain natural frequencies of the plate. Displacement fields of the plate are postulated by trigonometric series function. depending on the arrangement and orientation of the fibers, mindlin plate is assumed to be orthotropic or monoclinic.this analysis is useful to study the mechanical behavior of an angle ply lamina and effect of fiber orientation on the frequency response of the plate.the analysis can be extended for the laminates where the analytical solutions are not available. Finally the results are compared with those reported in the literature.
Analysis of Process Parameters of Plasma Arc Cutting of Stainless Steel Using Taguchi Method
Authors: Maity Kali Pada , Singh Vivek , Bhartiya Sachin
Published: October 2011

Plasma Arc Machining is one of the most important non conventional machining method used in fabrication industries because of its high accuracy, ability to machine any hard material, ability to produce any intricate shape and better finish. In the present investigation, plasma arc cutting of stainless steel (316L) materials has been carried out using plasma arc cutting machine. The optimization of process has been carried out using Taguchi method of design of experiment.
Nonlinear Dynamics of Rotors due to Large Deformations and Shear Effects
Authors: Shad Muhammad Rizwan , Michon Guilhem , Berlioz Alain
Published: October 2011

An analysis of linear and nonlinear dynamics of rotors is presented taking into account the shear effects. The nonlinearity arises due to the consideration of large deformations in bending. The rotor system studied is composed of a rigid disk and a circular shaft. In order to study the combined effect of rotary inertia and shear effects the shaft is modeled as a Timoshenko beam of circular cross section. A mathematical model is developed consisting of 4th order coupled nonlinear differential equations of motion. Method of multiple scales is used to solve these nonlinear equations. Linear and nonlinear dynamic behavior is studied numerically for different values of slenderness ratio r. Resonant curves are plotted for the nonlinear analysis. Due to nonlinearity these curves are of hard spring type. This spring hardening effect is more visible for lower values of r. Also the nonlinear response amplitude is higher when shear deformations are taken into account.
The Study of Residual Stress in Welded Specimens of Aluminium Alloy by Using Acoustic Emission Method
Authors: Saeidi Nia Zaman , Ahmadi Najaf Abadi Mehdi , Jawabvar D.
Published: October 2011

Welding is one of the most significant causes of residual stresses and typically produces large tensile stresses whose maximum value can be approximately equal to the yield strength of the materials being joined. These large tensile stresses are often responsible for premature component failure. Metallurgical welding joints are extensively used in the fabrication industry, including ships, offshore structures, steel bridge, and pressure vessels. In this study, residual stresses in welded specimens of AL–6061 were evaluated by using ACOUSTIC EMISSION method which is one of the nondestructive tests. In this work, AE signals formed during the tensile test of welded specimens were investigated. The results show that AE signals in specimens which have large amount of residual stress were detected in less load.
Mechanochemical Synthesis of Hydroxyapatite Nanopowder: Effects of Rotation Speed and Milling Time on Powder Properties
Authors: Abu Bakar Sharifah Adzila Syed , Sopyan Iis , Bin Abd Shukor Mohd Hamdi
Published: October 2011

Mechanochemical synthesis of two or more different precursors is a simple method to prepare metallic alloys, polymer and ceramic composite materials. This mechanical reaction based synthesis also has been employed to produce hydroxyapatite (HA) powder for bone implant application. In this present study, we employed mechanochemical method to synthesize hydroxyapatite nanopowder from dry mixture of calcium hydroxide (Ca (OH)2) and di-ammonium hydrogen phosphate [(NH4)2HPO4] powders. The effect of mechanochemical process on powder properties was investigated. Three rotation speeds of 170 rpm (M1), 270 rpm (M2) and 370 rpm (M3) were chose with 15 hours milling time respectively. The milling time at 370 rpm (M3) was extended to 30 hours (T1) and 60 hours (T2). Characterization of nanopowders were accomplished by Fourier transform infrared (FTIR), X-ray diffraction (XRD), nanosizer analysis, field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Rotation speed and milling time affected the obtained powders with nanocrystallite HA structure. The narrow peaks appeared with the incremental of crystallite size (9 – 21 nm) and crystallinity (21-59%) when the rotation speed was increased to 370 rpm (M3). However, particle size distribution (322-192 nm) was decreased with the rotation speed. Morphological evaluation indicated that the average particle size of resultant powder which consists of agglomerate crystals and irregular shapes reached about 17 - 36 nm. The as synthesized nanopowder showed that 370 rpm at 15 hours of milling is the suitable parameter to be applied for hydroxyapatite nanopowder synthesis in mechanochemical method.
Preparation of Dense Biphasic Calcium Phosphate Ceramics Using Eggshell Derived Nanopowders
Authors: Sopyan Iis , Adlina S. F. , Mohamad S.A.
Published: October 2011

This paper discusses the dependence of microstructure and mechanical properties of sintered biphasic calcium phosphate (BCP) on sintering temperature and compacting pressure of BCP dense bodies. BCP nanopowders were prepared via hydrothermal method using eggshell as the calcium source, followed by compaction into circular disc shape at various pressure and sintered pressureless in air at various sintering temperatures. X-ray diffraction analysis of nanopowders revealed the existences of hydroxyapatite (HA) as the main phase, with β-tricalcium phosphate (β-TCP) and calcium pyrophosphate (CPP) as the second phases. Morphological evaluation by scanning electron microscopy showed BCP exhibited uniform microstructure at low temperature and coalescence of pores and exaggerated grain growth at increasing temperature. Mechanical strength tests shown by compression strength and Vickers’ hardness test revealed an increase of strength with increasing temperature of up to 1100°C, after which it dropped. Mechanical strength also proved to be better with higher compacting pressure.
Al2O3-Water Nanofluids in Convective Heat Transfer
Authors: Prajapati Om Shankar , Rajvanshi A. K.
Published: October 2011

Anofluids are suspensions of metallic or nonmetallic nanopowders in base liquid and can be employed to increase heat transfer rate in various applications. In this work turbulent flow forced convection heat transfer of Al2O3-water nanofluid inside an annular tube with variable wall temperature was investigated experimentally. The Nusselt number of nanofluid was obtained for various Reynolds numbers and nanoparticle concentrations at atmospheric pressure. The addition of nanoparticles in water enhances heat transfer coefficient and the enhancement increases with increase in the nanoparticle concentration and flow rate. Experimental results emphasize the enhancement of heat transfer due to nanoparticles presence in the fluid.
Breakup of Droplets in Micro and Nanofluidic T-Junctions
Authors: Bedram Ahmad , Moosavi Ali
Published: October 2011

We employ numerical simulations to investigate the breakup of droplets in micro-and nanoscale T junctions which are used to produce small droplets from a large droplet. A Volume Of Fluid (VOF) method was used and for verifying the accuracy of simulation the results compared with two analytical researches. Our results reveal that breakup time and breakup length of the droplets play important roles in handling these systems optimally. Our results also indicate that for nanoscale T-junctions by increasing the capillary number the performance increases while for the micro-scale systems there is a specific capillary number for which the system is in its optimum condition.
Mixed Convective Heat Transfer Flow of Nanofluid past a Permeable Vertical Flat Plate with Magnetic Effects: A Finite Element Study
Authors: Rana Puneet , Bhargava Rama R.
Published: October 2011

Steady, two dimensional mixed convection laminar boundary layer flow of incompressible nanofluid along a permeable vertical semi-infinite flat plate with magnetic field effects has been investigated numerically. The resulting govering equations (obtained from the boussinesq) with associated boundary conditions are solved, using a robust, extensively validated, Galerkin Finite Element Method for different types of spherical shaped metal oxide nanoparticles with two different ratios of the nanolayer thickness to the original particle radius (0.02 or 0.1). The effects of the parameters governing the problems are discussed and shown graphically. The present study is of immediate interest in next-generation solar film collectors, heat exchangers technology, material processing exploiting vertical surfaces and all those processes which are highly affected with heat transfer.
Modeling and Simulation of Controlled Manipulation by AFM Nano Robot
Authors: Hoshiar Ali Kafash , Khalili Mohamad Reza , Nejad Mahmood Hashemi , Fard Hafez Raeisi
Published: October 2011

In this article a model to describe relation between AFM cantilever’s deformation and force (as a force transducer) is developed. Furthermore a state space model is used to find suitable feedback control. A model which relates force and deformation is described. To verify a Finite element simulation is applied and a control algorithm for manipulation purpose is found. Moreover based on nature of the process control system is designed. Due to recent developments in AFM nanorobot applications in biotechnology and manufacturing nanostructures, understanding of cantilever’s response and process control have received great importance.
Flow Characteristics of Nanofluids According to Nanoparticles Shape
Authors: Hwang Kyo Sik , Baek Il Kwon , Shin Hyun Kyo , Jang Seok Pil
Published: October 2011

In this paper, flow characteristics of water-based Al2O3 nanofluids according to nanoparticles shape are experimentally investigated in fully developed laminar flow regime. Al2O3 nanofluids of 0.3 Vol. % with sphere-, rod-, blade-, platelet-and brick-shaped nanoparticles are manufactured by the two-step method. Nanoparticles shape dispersed in base fluid are also checked using TEM image. Zeta potential and sedimentation are measured to examine suspension and dispersion characteristics of Al2O3 nanofluids with nanoparticles of various shapes. Based on the experimental results, it is found that the pressure drop of Al2O3 nanofluids strongly depends on the shape of nanoparticles at the fixed volume fraction of 0.3%. We experimentally show that the pressure drop characteristics of Al2O3 nanofluids can be explained by both the surface area per unit mass and the size of nanoparticles which are related with the shape of nanoparticles.
The Formation of Diamond-Like Carbon Film at Atmospheric Pressure by the Pulsed Laser/Plasma Hybrid Deposition Method
Authors: Wang Han Pei , Lin Jehn Ming
Published: October 2011

A pulsed laser/plasma hybrid deposition method has been developed to produce the diamond-like carbon (DLC) film at atmospheric pressure in this work. A plasma torch was used to heat up the carbon particles which were simultaneously ablated by a pulsed laser, thus the kinetic energy of the carbon particle can be increased to form the carbon atoms with amorphous bonding structure of the DLC film. The influences of the plasma flow have been examined at various inlet pressures. According to the experimental results of the carbon film inspected by the Raman spectroscopy, it reveals that the intensity ratio of the D-band to G-band of the carbon film can be reduced to 0.5 by the implementation of plasma flow. Therefore the DLC film was solidly formed. The adhesive strength of the DLC film was also characterized by the scratch test, it can be found that the critical loading of the film on the iron substrate is up to 19 N.
Nano Technology/Networks in Molecular Communication: An Advance Step of Electrical Communications
Authors: Govil Jivika , Govil Jivesh , Gupta Aishvarya , Gupta Vidhi
Published: October 2011

Till-date research in communications industry has mainly focused on systems based on electromagnetic propagation. However, in nanotechnology the scales are very minute, hence it needs further research that whether these concepts apply or not. So far, molecular communications research has studied the propagation of individual molecules between closely spaced transmitters and receivers as embedded in a fluid medium. Using these concepts, scientists are now investigating into nanomachines, nanomedicines, nanorobotics, and bio-chips which have enabled to further the computer science communications with biologically inspired algorithms. If timely parallels can be drawn between molecular communications and electrical communications there is potential for cross-learning and an opportunity to pioneer new developments. This paper aims to bring forth the key principles in molecular communication and their relationship to electrical communications as out-of-the-box philosophy for academicians and students.
Nanostructure Multilayers as Broadband Antireflection Coating Used at Terahertz Frequencies Region
Authors: Wang Wen Liang , Rong Xiao Hong
Published: October 2011

Over the past decades, there have been significant advances in techniques to generate and detect terahertz (THZ) signals, but there have been comparatively few reports of structures that manipulate and control them. In this paper, based on the characteristic matrix method, hydrogenated amorphous silicon (a-Si [H]) and silicon oxide (SiO2) were chosen as coating materials, a nanostructure multiplayers as broadband antireflection coating used at terahertz frequencies region was designed. Which has a residual reflectivity of less than 0.07 and average reflectivity about 0.05 throughout the 50–140 cm-1 region
Crystallization Time Dependence of Nanohybrid Shish-Kebab Structure in HDPE/PA66 Nanofibers Composites via Solution Crystallization
Authors: Han Wen Juan , Zheng Guo Qiang , Liang Yan Yan , Liu Chun Tai , Shen Chang Yu
Published: October 2011

In this study, PA66 nanofibers were successfully solution electrospun. The crystalline morphological features of HDPE solution induced by nanofibers were investigated by scanning electron microscopy (SEM). Nanohybrid shish-kebab (NHSK) can be formed in HDPE solution via isothermal crystallization, in which PA66 nanofibers serve as shish and HDPE lamellae act as kebabs surrounding the nanofibers periodically. Additionally, crystallization time has significant effect on the structure of HDPE kebab in NHSK, i.e., as crystallization time increases, the size of the kebab increases and the crystals decorated on PA66 nanofibers exhibit a three-dimensional growth (i.e., aggregate of crystallites) rather than a two-dimensional one (i.e., disc-like lamellae normal to the axis of nanofiber).
Preparation of Nano-Coenzyme Q10 by Water Jet Comminution
Authors: Li Jin Zhi , Shen Zhi Gang , Ma Shu Lin , Xing Yu Shan
Published: October 2011

Nanoparticles usually prepared through chemical synthetic method. In our study, nanoCoenzyme Q10 was prepared by water jet comminution process. The results were characterized with scanning electron microscope (SEM) and the color change of the water solution. The color becomes lighter when the particles have a smaller size. The effect of comminution is related to the number of process cycles. nanoCoenzyme Q10 water solution (particle size less than 50nm) was obtained through water jet comminution at 50Mpa with five cycles. This new method not only solves the problem of physical comminution collection, but also gives an effective way to prepare natural nanoparticles.
New Method for Preparing Rubber/Clay Nanocomposites
Authors: Tan Jing Hua , Wang Xiao Ping , Luo Yuan Fang , Jia De Min
Published: October 2011

Rubber/Ca-montmorillonite (Ca-MMT) nanocomposites with exfoliated Ca-MMT layers was prepared by a new preparation method named masterbatch method, in which the masterbatch was prepared by co-coagulating nature rubber latex and bis [3-triethoxysilylpropyl-] tetrasulfide (TESPT) modified Ca-MMT aqueous suspension and then the masterbatch accompanied with carbon black (N220) were used in the system of SBR and ENR. The properties of TESPT in-situ modified Ca-MMT were investigated by Fourier-transform infrared spectroscopy and thermogravimetric analysis. The results showed that the TESPT has reacted with the surface groups of Ca-MMT. The dispersion of the Ca-MMT in masterbatch and vulcanized sample was characterized by X-ray diffraction. The results showed that in the masterbatch an exfoliated structure was obtained and in the vulcanized sample a coexistence of intercalated-exfoliated structure was obtained. The influence of the Ca-MMT loading on the structure and properties of the nanocomposites were studied. It was found that the incorporation of Ca-MMT hindered the vulcanization, improved mechanical properties, thermal properties and aging resistance properties. The dynamic mechanical analysis results showed a decrease of tanδ max when the Ca-MMT is added.
Buckling Behaviors of Imperfect Single-Walled Carbon Nanotubes: A Molecular Dynamic Simulation
Authors: Li Yong , Guo Zao Yang , Peng Bei
Published: October 2011

Carbon nanotube has attracted tremendous scientific and industrial interests due to its exceptional mechanical, electrical and thermal properties. In this paper, classic molecular dynamic simulations are carried out to investigate the buckling behaviors and mechanical properties of single-walled carbon nanotubes under axial compression, both for perfect and imperfect ones introducing atomic vacancies. The effect of chirality, diameter, quantity and position of vacancy are systematically studied. The simulation results reveal that their mechanical properties such as Young’s modulus, critical strain and stress suffering a significant decline as the increasing numbers of vacancies. It is also found that the critical stress and strain are sensitive to position of atomic vacancy. Carbon nanotubes with vacancies located at the center have lower critical strain and are easier to reach the failure stage than those with vacancies at both sides.
Production of Transparent Heat Windows of TiO2/Ag/TiO2, and Investigation of their Nanostructures
Authors: Behforooz Mohammad Reza , Kangarloo Haleh
Published: October 2011

Using the resistive heated method, TiO2/Ag/TiO2 thin files (Transparent heat windows) in vertical deposition angle were deposited on SiO2 substrate, in high vacuum (HV) condition and 100°c. The thickness of TiO2 on glass substrate was 50°A, Silver film 125°A and 225°A and the upper layer TiO2 with 115°A. All other deposition conditions were same for both samples .Atomic force microscope (AFM), and spectrophotometric methods were used to study the nanostructures of these samples in the range of FTIR. The purpose of this work is to find and produce the structure with the least energy waste.
Nanocomputation of Mechanical Properties in Nanobio Membrane
Authors: Maftouni N. , Amininassab M. , Mello M. N. , Marink S.
Published: October 2011

It is very essential to know mechanical properties in different regions of nanobio membrane as one of the most important parts of living systems. Here the coarse-grained (CG) simulations method have been used to study the pressure profile in a system including nanobio membrane and water. CG simulations have become an important tool to study many biomolecular processes, exploring scales inaccessible to traditional models of atomistic resolution. One of the major simplifications of CG models is the representation of the solvent, which is either implicit or modeled explicitly as a van der Waals particle. The effect of polarization has been ignored in the initial CG water molecules model. Given the important role of water as a solvent in biological systems, its treatment is very important to the properties derived from simulation studies. Till now two models have been parameterized to simulate water: i) standard MARTINI water and ii) polarizable coarse-grained water model. Both of mentioned water models are proper to be used in combination with the CG MARTINI force field. In this work both of these models have been used for simulation. One micro second CG molecular dynamics simulation has been done for two separate systems. Each system includes water and hydrated 1-palmitoyl-2-oleoyl-1-sn-3-phosphatidylcholine (POPC) lipid nanobio membrane. The difference between two systems is in simulated water models that one system has standard MARTINI water and the other one has polarizable water. In each case pressure profile calculation has been done via Virial pressure theorem. Results indicate that using polarizable water model leads to higher picks in pressure profile in water region near surface of nanobio membrane. This can be related to density of polarizable water and also may play role as a small barrier.
A New Solution Seed for Job Shop Scheduling Problem
Authors: Fattahi Parviz , Manesh Mojdeh Shirazi , Roshani Abdolreza
Published: October 2011

Scheduling for job shop is very important in both fields of production management and combinatorial optimization. Since the problem is well known as NP-Hard class, many metaheuristic approaches are developed to solve the medium and large scale problems. One of the main elements of these metaheuristics is the solution seed structure. Solution seed represent the coding structure of real solution. In this paper, a new solution seed for job shop scheduling is presented. This solution seed is compared with a famous solution seed presented for the job shop scheduling. Since the problem is well known as NP-Hard class, a Tabu search algorithm is developed to solve large scale problems. The proposed solution seed are examined using an example and tabu search algorithm.
Systematic Layout Planning to Assist Plant Layout: Case Study Pulley Factory
Authors: Watanapa Anucha , Wiyaratn Wisitsree
Published: October 2011

In this study, the application of a systematic plant layout planning (SLP) to assist the optimum design of process areas and locations is proposed. The number of machines and space requirement in pulley factory is determined. The operation process chart, flow of material and activity relationship chart have been investigated. The relationships between machines, operation sections and material flow are used to determine the suitable position of each activity. The SLP method has been employed to design the two alternative plant layouts and compare the performances between new layout and present layout in term of material flow. The new plant layout is modified by moving a disassembly and surface finish that significantly decrease the distance of material flow, so it is effective increasing production.
A Stochastic Savings Algorithm for Vehicle Routing Problem with a Centralized Distribution Center and Delivery Time Window
Authors: Sanjaiya Methinee , Buddhakulsomsiri Jirachai , Parthanadee Parthana
Published: October 2011

The vehicle routing problem (VRP) under study involves managing a fleet of trucks existing to provide transportation services from a centralized distribution center (DC) to a set of geographically dispersed customers. The problem is motivated by a real problem from one of the large chains of high-end retail stores in Thailand. The objective of this study is to develop a simple and effective algorithm that can help the user manage the fleet in order to reduce the total transportation cost. The developed algorithm is based on the parallel savings algorithm but with a stochastic component that has a capability of escaping the local optima. The stochastic component applied a biased random sampling (BRS) and regret based random sampling (RBRS) to the selection of customers to add to delivery routes. Specifically, the selection probabilities are computed proportionally from the savings value of merging customers. The algorithm generates solutions containing delivery routes and schedules for all trucks in the fleet that satisfy daily store demands under limited truck capacity and delivery time window restrictions. Three measures of performance include the total distance, total travel time, and total cost. Computational test of the algorithm was performed on a set of standard problems, and promising results are obtained.
Output Regulation of the Liu Chaotic System
Authors: Sundarapandian Vaidyanathan
Published: October 2011

This paper investigates the problem of regulating the output of the Liu chaotic system (2004). Explicitly, we construct state feedback control laws to regulate the Liu chaotic system so as to track constant reference signals. The control laws are derived using the regulator equations of Byrnes and Isidori (1990), who have solved the output regulation of nonlinear control systems using neutrally stable exosystem dynamics. The simulation results are also discussed in detail.
A Framework for Implementing Lean Manufacturing System in Small and Medium Enterprises
Authors: Wanitwattanakosol Jirapat , Sopadang Apichat
Published: October 2011

—In this paper, a conceptual framework to apply many techniques for implementing lean in the high-variety low-volume (HVLV) environment is presented. Lean production has increasingly being implemented as a potential solution for many organizations. Anyway, the lean formula is applicable directly only to the make-to-stock business, but the make-to-order (MTO) product environment has to adapt lean manufacturing principle. The method of this paper has a two-phase quantitative framework to transform small and medium enterprises (SMEs) to be lean. Phase 1 has three interrelated components: (1) re-engineering an organization by using the power of computer simulation combined with business process. (2) Value stream mapping (VSM) is used to create a map of both value and waste in a given process. This tool has also a main drawback for job shop facility because many value streams are composed of hundreds of industrial parts and products. (3) Integrative supplier relationship is one of the most critical factors to maintain an advantage in the increasing levels of competition. Phase 2 performs a just in time production schedule by using ant colony optimization technique combines with a simulation tool. The aims of this paper are to develop a suitable lean manufacturing system for SMEs and to study the performance of the system for improving effectiveness. The result shows how to combine lean concept with simulation optimization, the step of this framework to obtain the optimization solution.
The Evaluation of Priority Rules in Operations Scheduling
Authors: Iringová Miriam , Važan Pavel , Jurovatá Dominika
Published: October 2011

The main objective of the project was to investigate the influence of the selected priority rules of technological operations on chosen production goals. The paper presents the results of the project. The dynamic scheduling process of operations was simulated on the model of production system. The effect of each priority rule has been studied for different production goals in different stressful situations. The synthesis and the evaluation of results were performed by using mathematical and statistical methods. The multi-objective evaluations scoring method have been chosen by authors.
Viability of Lean Manufacturing Tools and Techniques in the Apparel Industry in Sri Lanka
Authors: Silva S.K.P.N. , Perera H.S.C. , Samarasinghe G.D.
Published: October 2011

Lean Manufacturing can be considered as a business strategy which was originated and developed in Japan. It tries to identify waste and eliminate it. Thus it leads to improvement in productivity and quality and companies can achieve a competitive advantage over others. Sri Lankan industries, especially apparel sector have attempted to implement this, but a little research work is carried out in regarding its suitability. This research is an attempt to identify a suitable Lean model for the apparel industry in Sri Lanka. As the initial stage of this study, a literature review is carried out to study about the Lean Manufacturing. It starts by looking at how Lean Manufacturing first began. Then it seeks to identify the core principles, tools and techniques and how those tools and techniques are currently being used worldwide. After studying the global scenario the next step is to look at the Sri Lankan context using real world data. This was undertaken by means of structured surveys, observations, and on site interviews. Also the study will reveal period of Lean implementation, suitable implementation methods, order of implementation, tools which are avoided, sustainability of different tools, challenges faced, ways of overcoming challenges and benefits achieved after applying Lean Manufacturing concepts in the apparel sector of Sri Lanka. The findings state Lean Manufacturing can be applied to mass production apparel industries and has created a positive mindset on employees. As implementation of Lean concepts is still in developmental stage, the full benefit is not yet achieved. But current situation suggests that the industry can go forward with Lean and capitalize on its full potential. In this research the authors have proposed a model which can be used to implement Lean in a systematic manner and each manufacturer must develop their own Lean system through training, experiments, employee empowerment, right leadership and kaizen mindset. Originality of the research— The research builds up a Lean Model which is not yet developed for the apparel sector in Sri Lanka. It can be further modified to suit the global apparel industry and other industries as well.
Overall Maintenance Time Reduction by Optimizing the Distance of Service Center in Manufacturing Unit through Single Facility Location Planning
Authors: Vishwakarma Manish , Khare V.K.
Published: October 2011

A new methodology has been proposed to optimize both the planning of preventive maintenance and the time required to perform maintenance in a process plant is presented. In the Plant Maintenance process there is an increased need to make the shop floor layout more easily reachable user pliable. This allows Plant Maintenance staff to focus more on minimizing downtime and increasing productivity. Being more mobile allows them to go from more reactive maintenance to proactive maintenance. In this paper a single facility location problem with multiple relocation opportunities is investigated. The weight associated with each demand point is a known function of distance and time. We consider either rectilinear, or squared Euclidean, or Euclidean distances. The objective function is to minimize the total travelling distance from service center to various machines locations,thereby reducing the total maintenance time.
The Application Effect Analysis of Lean Production in China
Authors: Zhang Hong Liang , Wu Chun Hua , Niu Zhan Wen
Published: October 2011

Lean production, which is regarded as the third production mode after craft-ship and mass production mode, now is being applied widely by more and more enterprises. Toyota Motor Corporation as well as many other enterprises’s success has proved that lean production is one of the most scientific and advanced production models in the world. In order to upgrade management level and decrease technology gap with foreign enterprises, the enterprises of our country began to contact and learn lean production at the late of 1970s, but till now the relative study is far behind compared with that of western country. This situation has impeded the application and development of lean production in China. Pointed to this situation, this paper does application appraisal of lean production using data get by questionnaire. In the process of appraisal, data envelopment analysis is used to do analysis from the angle of relative efficiency. This method can weaken the impaction of enterprise’s scale and its development stage as well as other factors so the appraisal result will be more objective and impartial. In order to get reasonable and scientific analysis result, this paper does study using not only financial performance index but also non financial index, because traditional financial indexes cannot cover the traits of lean production. The quantitative anlysis result shows that lean production’s implementation has profound influence to upgrade enterprises’ relative efficiency.
Minimizing the Number of Tardy Jobs in Flow Shop Sequence Dependent Setup Times Scheduling Problem
Authors: Varmazyar Mohsen , Salmasi Nasser
Published: October 2011

This paper investigates permutation flow shop scheduling problems with sequence-dependent setup times with minimizing the number of tardy jobs as criterion (Fm|prmu, Sijk|∑Uj). Since the proposed research problem has been proven to be NP-hard, three different meta heuristic algorithms based on tabu search (TS) has been proposed to solve the problem. These three algorithms are different based on their tabu list characteristics. In order to evaluate the performance of the proposed TS algorithms, test problems in different ranges are generated to find the best algorithm. The comparison shows that the TS algorithm which its tabu list keeps track of the slots that the jobs are assigned has a better performance than the other algorithms
Towards Lean Factory-Combining Lean Thinking with Promising Manufacturing Method - A Case of Finnish Boating Industry
Authors: Ehrs Mikael , Rymaszewska Anna , Pekkala Janne
Published: October 2011

The Finnish boating industry is currently facing various challenges that force it to rethink the traditional way of working. Growing manufacturing costs, competition from low labor cost countries as well as new regulations regarding styrene emissions are one of the major factors imposing a change on boat manufacturers. The article focuses on the analysis of Finnish boating industry situation and identification of possible development opportunities. The particular attention is put on lean manufacturing principles and its application in small and medium-sized companies that dominate the market. The aim is to propose a concept factory for boating industry-a factory that would put the lean thinking into practice. Only the most appropriate and promising concepts are proposed. The method for concepts selection is based on the analysis of the industry’s current situation examined with the help of in-depth interviews conducted in boating and rotational molding companies in Finland.