bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Span Length on the Tensile Properties of Natural Fibers
Authors: Biswas S. , Ahsan Qumrul , Verpoest Ignaas , Hasan Mahbub
Published: July 2011

Natural fibers are widely used as “reinforcing agents” in polymer composites. The aim of the current study is to evaluate the effect of span length on the tensile properties of several natural fibers (Vietnamese coir and bamboo and Bangladeshi jute). Tensile testing of jute, bamboo and coir fibers was carried out by varying span length (5, 10, 15, 25 and 35 mm). The Young’s modulus and strain to failure were corrected by using newly developed analytical equations in order to correlate the Young’s modulus and strain to failure of natural fibers. Scanning electron microscopy of the fibers was also carried out. It is clearly observed that the Young’s modulus increased with an increase in span length. Whereas tensile strength and strain to failure decreased with an increase in the span length of single fibers. The correction method resulted in a high Young’s modulus for larger span, while strain to failure found was lower compared to smaller span. This is because larger span length helps to minimize the machine displacement compared to smaller ones. Among all fibers, the Young’s modulus of bamboo fiber was highest, followed by jute and coir respectively. Jute fiber had smoother surface and compact structure compared to other two fibers.
Numerical Study of Cracked Titanium Shell under Compression
Authors: Ayari F. , Zghal Ali , Bayraktar E.
Published: July 2011

In many industrial conditions, light thin titanium shells are well used under various severe loading conditions. It is of interest to know the real conditions that govern the instability of a cracked panel subject to buckling loads in order to conserve as maximum as possible the strength of the structure. Several parameters can be varied in order to achieve this objective. The aim of this study is to determine the evolution of these parameters in order to achieve optimal crack propagation conditions while keeping these parameters within “reasonable” limits of physical and economic feasibility. For the purpose of the current study the considered structure can be regarded as thin cylindrical shell of radius r, thickness t with an initial through crack of length a. The titanium cylindrical shell is sealed on one edge and compression is applied on the other. An additional applied pressure can generates a stress and deformation field around the crack tip that has bending stresses and membrane stresses and appears as a bulge around the crack area. This paper give details of a simulation with FEA numerical analysis that determine governing instability conditions of a Titanium shell under particular loading conditions and to put in light the effect of bulging on the stress intensity factor at the crack tips. This bulging factor measures the severity of the stress intensity in the bulged crack compared to a plane shell subjected to equivalent loading conditions.
An Influence of a Binder System to the Rheological Behavior of the SS316L Metal Injection Molding (MIM) Feedstock
Authors: Jamaludin Khairur Rijal , Muhamad Norhamidi , Abolhasani Hooman , Murthadha Hadi , Rahman Mohd Nizam Ab.
Published: July 2011

The influence of a binder system to the rheological behavior of a Metal Injection Molding (MIM) feedstock is presented in the paper. The binder systems used are: a) PEG & PMMA b) Palm stearin & LLDPE and, c) Tapioca starch & LLDPE. The viscosity and shear rate of the feedstocks were measured at various range of temperature and shear rate across the L/D = 10 capillary rheometer. The flow behavior index, n and activation energy, E of each feedstock were measured to show its significance as MIM feedstock. Generally, the result indicates all feedstock exhibits a shear thinning behavior and the binders are suitable as MIM binder. Additionally, the present paper has discovered that the binder system does not have much influence to the activation energy. In order to show the relevance of the rheological behavior to the actual injection molding performance, green parts has been injection molded and the result shows an agreement with the rheological behavior result.
Electrical Properties of Carbon Nanotubes-Based Epoxy Nanocomposites for High Electrical Conductive Plate
Authors: Suherman Hendra , Sahari Jaafar , Sulong Abu Bakar
Published: July 2011

Electrical properties of carbon nanotubes-based epoxy nanocomposites for high electrical conductive plate were investigated. Dispersion and incorporation mechanism between two conductive fillers with different sizes (CNTs and Graphite) in the polymer matrix are the key factors in the fabrication of high electrical conductivity plate. Different variation of carbon nanotubes (CNTs) (1~10 wt %) and Graphite (G) (60 ~ 69 wt %) loading concentration were added into the epoxy resin. Dispersion of CNTs and G in epoxy resin were conducted by the internal mixer with a Haake torque rheometer. The mixture of G/CNTs/EP was poured into the steel mold, and G/CNTs/EP nanocomposites had been fabricated through compression molding. The electrical conductivity of nanocomposites in terms of variation of G and CNTs concentration were measured by the four point probe for in a plane electrical conductivity. The results revealed that addition of G/CNTs and increasing curing temperature are effective ways to produce high electrical conductive nanocomposites. The highest electrical conductivity was reached on 104.7 S/cm by addition 7.5 wt% of CNTs. Dispersion quality of G and CNTs in the epoxy matrix was observed on the fractured surface by scanning electron microscopic.
Effects of Type and Concentration of Initiator on Grafting of Acrylic Monomer onto Depolymerized Natural Rubber
Authors: Prasoetsopha N. , Chumsamrong Pranee , Suppakarn Nitinat
Published: July 2011

Highly crosslinked epoxy resin for engineering applications is normally stiff but brittle. Therefore, many attempts have been made to improve its toughness. Nowadays, several studies have been done on toughening epoxy resin using natural rubber (NR) because it is abundant and comes from renewable resource. In the present work, NR was subjected to depolymerize in order to achieve molecular dispersion of NR in epoxy matrix. Depolymerized natural rubber (DNR) was prepared by adding a carbonyl compound to natural rubber latex solution and subjecting the mixture to air oxidation in the presence of a radical forming agent at 70°C. In addition, the interfacial adhesion between rubber and matrix must be present to achieve a significant increase in toughness. Hence, DNR was further functionalized by grafting with monomer mixture of methyl methacrylate (MMA)/glycidyl methacrylate (GMA) (90/10 wt/wt%) in an amount of 50% based on rubber content. Solution polymerization was used to graft such monomers using 2 hours reaction times at a reaction temperature of 80oC. Two types of initiator used were benzoyl peroxide (BPO) and azo-bisisobutyronitrile (AIBN). The amounts of initiator in the grafting process were 1, 2, and 3 parts per hundred of DNR. Effects of type and concentration of initiator on grafting efficiency of MMA/GMA monomer mixture onto depolymerized natural rubber were studied by proton nuclear magnetic resonance (1H-NMR) analysis. The molecular weight of DNR was characterized by gel permeation chromatography (GPC). The results indicated good evidence for the formation of graft co-polymers in the presence of both initiators, AIBN or BPO. However, the amounts of grafted MMA/GMA on DNR backbone using BPO was higher than those on DNR backbone using AIBN.
Compressive Strength of Rice Husk Filled Resin
Authors: Ibrahim W.M.A. , Kuek S.Y.
Published: July 2011

The findings for strengthening and repair of implant materials are stepping up to ensure better protection of the patients. The utilization of composite resin is favourable to combat this challenge. However, it being a brittle material does not entitle it to be used in the design. Hence, epoxy resin combining with silicon oxide filler from the rice husk; is a relatively new material in biomedical engineering, enable it to meet its fullest strength and flexibility. Work was performed at laboratory to extract the silicone compound from rice husk and as well investigate the compressive strength of rice husk filled resin material. Initially the rice husk was experimented by undergoing pre-treatment, chemical treatment and incineration process to obtain silicone compound. The silicone compound was later mixed with epoxy resin at different percentage of filler. In the final stage, the compressive strength of rice husk filled resin was analyzed and affirmed experimentally based on the ASTM standards. The results obtained were then analyzed using analytical software SPSS. Epoxy resin filled with 20% silica from rice husk gave the optimum compressive strength of 90 Mpa.
Characterisation of Titanium Alloy Feedstock for Metal Injection Moulding Using Palm Stearin Binder System
Authors: Mohamad Nor Nor Hafiez , Muhamad Norhamidi , Jamaludin Khairur Rijal , Ahmad Sufizar , Ibrahim Mohd Halim Irwan
Published: July 2011

Metal injection moulding (MIM) is a cost-effective technique for producing small, complex, precision parts in high volume. Each step in MIM process plays a vital role in order to achieve high quality final product. To have a good understanding of the MIM process and successful in manufacturing, characterisation of the material feedstock is essential. This paper presents the characterization of MIM feedstock consisting titanium alloy (Ti-6Al-4V) powder mix with binder 60 wt% of palm stearin and 40 wt% polyethylene. The characterisation of Ti-6Al-4V alloy powder, binders and feedstock includes scanning electron micrograph (SEM), thermo gravimetric analysis (TGA), differential scanning calorimeter (DCS) and rheological test were established. Rheological results exhibited pseudoplastic or shear thinning flow behaviour, where its viscosity decreased with increasing shear rate. The feedstock viscosity also decreased with increasing temperature and was found to be suitable for moulding.
Scanning Path Planning in Laser Bending of Tube Based on Curvature
Authors: Wang Xu Yue , Wang Jun , Wang L.J. , Xu W.J. , Guo D.M.
Published: July 2011

A method is presented based on geometric-curvature characteristics in which a scanning path planning for laser bending of a straight tube into a curve tube in a two- and three-dimensional space. In a two-dimensional (plane) bending, the steel tube is divided into several segments according to the extreme point and inflection point of the desired shape of the tube, taking the extreme point as the initial place of the path planning, using different scanning space for every segment in order to identify the scanning paths. For a tube bending in a three-dimensional space, a projection decomposition method is used, where the three-dimensional is decomposed into two two-dimensions, and respective scanning path planning and process parameters are thus acquired. By combining the data in the two-dimensional planes, the three-dimensional scanning path plan was obtained. Finally, an experimental verification is carried out to bend straight tubes into a two-dimensional sinusoidal and a three-dimensional helical coil-shaped tube. The results show that the proposed method of scanning path planning is effective and feasible.
Determination of Uniaxial Flow Stress Curve Using Aero-Bulge Test for Very Thin Copper Sheet
Authors: Kim J. , Suh J. , Hoffmann Hartmut , Golle Roland
Published: July 2011

Determination of the flow stress curve is an important step for precisely describing material behavior in Finite Element simulations. The flow stress curve is generally determined by taking a uniaxial tensile test as a standard. In the case of very thin sheet, since the fracture is generated at a low strain, there is not enough uniaxial data obtained to be applied in the FE simulation. The reason for this is that charactering plastic deformation at a large strain values by extrapolating a flow stress curve which is based on insufficient measurement data is highly susceptible to error. Bulge test is useful method for determining the equivalent biaxial flow stress curve up to a large strain. In this paper, the biaxial flow stresses curve for very thin copper sheet with thickness 35 and 50 μm were determined using the aero-bulge test. A new empirical model was derived for the estimation of the sheet thickness at the pole. After the compatibility between uniaxial and biaxial flow stresses was verified, the uniaxial flow stress curve was determined from the aero-bulge test using reverse engineering. The methodology of extrapolation of the flow stress curve at a large strain was finally proposed for application in FE simulations.
Effect of Aluminum Nitride Addition on Dry Wear Properties of Al-11%Si Alloy Prepared by Stir Casting Process
Authors: Wahab Mahamad Noor , Ghazali Mariyam Jameelah , Daud Abdul Razak
Published: July 2011

Dry wear properties of aluminum nitride (AlN) reinforced aluminum-11% silicon alloy (Al-11%Si) was studied using a pin-on-disc configuration wear tester. Different weight percentages of AlN (0 – 10 wt.%) powder were added to the Al-Si alloy, melt and stir cast via bottom pour technique to form composites of Al-Si alloy/AlN. The dry sliding wear test were performed at a room temperature (27°C), under 25N and 70N load with fixed velocity of 1ms-1 and sliding distance between 1 to 5 km. The addition of 10 wt% of AlN improved wear resistance of Al-Si alloy by 72% and 130% indicated by volume loss for 25N and 70N load respectively. Mixed-wear mechanism of delamination, adhesion and abrasion was observed for the composite when applied loads were 25N and 70N while delaminating mechanism was dominance for Al-Si matrix alloy. Both Al-Si alloy with and without AlN reinforced found with FE element from counter-face disk that shows material transfer was significant.
Microstructural Evolution of AZ91 Magnesium Alloy during Deformation and Heat Treatment
Authors: Li Jing Yuan , Xie Jian Xin
Published: July 2011

Microstructural evolutions of AZ91 magnesium alloy, which applied to homogenizing annealing treatment, hot extrusion and ageing treatment respectively, are investigated in this paper. Results exhibit that the massive β-Mg17Al12 phase appearing in the initial structure dissolves to eliminate in α-Mg matrix mostly due to the homogenizing annealing treatment; dynamic recrystallization and consequent grain refinement occur during extrusion; banded structure, in which the β-Mg17Al12 phase precipitates parallel to the extrusion direction in α-Mg matrix, are observed in the ageing treated specimen. Furthermore, the effects of temperature, keeping time of homogenizing annealing treatment and ageing treatment, and the extrusion processing parameter on the microstructural evolution of this alloy are also discussed according to the experimental results in details. In addition, the various mechanisms of the morphology and quantity of α-Mg and β-Mg17Al12 phase are analyzed corresponded to the various states. As for the banded structure appearing in the ageing treated specimen, it can be attributed to the banded segregation which remained in the extruded one and resulted from the casting dendrite and subsequent extrusion.
Evaluation of Mechanical Properties and Various Pile-Up of Plate-Type Polymer Using Nanoindenter
Authors: Joung Y.N. , Kang Chung Gil , Lee S.M.
Published: July 2011

For producing high-quality components through a nanoimprint lithographic (NIL) process, it is important to measure quantitative properties about the behavior of polymers with regard to thermal-nano variation. NanoScale indents can be used as cells for molecular electronics and drug delivery and slots for integration into nanodevices; they can be used to detect defects for tailoring the structure and properties. This study evaluates the mechanical characteristics of polymers, such as Polymethylmetacrylate (PMMA) and COP (Cyclo-olefin Polymer), at high temperatures for the manufacture of nano/micro-sized polymers through thermal nanoindentation at high temperatures. At high temperatures, the mechanical properties of polymers exhibit extreme variation. When a polymer is heated, it becomes softer than at room temperature. In this regard, it is especially important to study the mechanical properties of polymers at high temperatures.
Structure Characterization of Electrodeposited Zinc Selenide Thin Films
Authors: Mohamad S.A. , Basirun Wan Jeffrey , Ibrahim Z.A. , Arof A.K. , Ebadi Mehdi
Published: July 2011

Crystalline thin of zinc selenide have been electrochemically deposited on conducting substrates of indium tin oxide, ITO glass. Initial investigation with voltammetry was done and shows that the zinc selenide films were stable towards oxidation. The best deposition potential obtained was at -0.95 V vs. Ag /AgCl while at lower deposition potentials, the films do not form well. Energy Dispersive Analysis and X-Ray spectrum indicate that the films deposited at 65oC and -0.95 V vs. Ag/AgCl have nearly stoichiometric Zn: Se ratio.
Microstructure and Electrical Properties of AZO Films Prepared by RF Magnetron Sputtering
Authors: Jufriadi Bakri , Sutjipto Agus Geter E. , Othman R. , Muhida R.
Published: July 2011

AZO is an ideal replacement transparent conducting oxide (TCO) for ITO to all corresponding applications. The typical applications include: transparent electrodes for solar cells, flat panel displays, LCD electrodes, electro-magnetic compatibility (RF-EMI shielding) coatings, touch panel transparent contacts, static discharge dissipation. The production of useful and commercially attractive thin films using different deposition processes is very important parameter to investigate. A systematic study of the sputtering condition and their influenced on electrical and structural were studied. In this work, AZO films were deposited by RF magnetron sputtering at 200 °C. The result shows that the deposited time has influenced the characteristic of deposited AZO films. For a longer deposition time, thin film shows a uniform grain growth. The resistivity found minimum at the deposition time of 45 minutes. It can be considered that by reducing of the grain boundaries which enable the electron carries to conduct smoothly.
Effects of Titanium Combined with Aluminium on the Electrochemical Properties and Efficiency of Mg-Mn Anodes
Authors: Fadaei E. , Emamy M. , Dehghanian C. , Karshenas M.
Published: July 2011

Magnesium sacrificial anodes are widely used in cathodic protection systems. In the present work, samples of Mg-0.7% Mn- x% Al- y% Ti (x,y = 0-0.6) alloys were electrochemically characterized to evaluate their performance as magnesium sacrificial anodes. The experiments focused on the influence of aluminium and titanium contents on the electrochemical behavior and efficiency of anodes. Aluminium and titanium was used in different concentrations ranging from 0.15 to 0.60 at.%. Short-term electrochemical tests, ASTM G97-89, as well as polarization curves were performed to obtain electrochemical behavior and efficiency and to reveal any tendencies to be passive. It is shown that by increasing titanium content an improvement of electrochemical properties of magnesium anode such as current capacity and electrochemical efficiency can be obtained.
Phase Formation during Reduction of Iron Sand with Soda Ash Flux Addition
Authors: Pramusanto  , Purwanto Hadi , Dahlan Yuhelda , Saleh Nuryadi
Published: July 2011

Iron sand deposit in Indonesia generally consisted of titanomagnetite with ilmenite lamelaa occurred in magnetite particle structure, therefore direct physical separation through magnetic method at particle size of 400 mesh only capable increasing total iron content up to 60%. In order to increase the grade of iron, decreasing TiO2 content in iron sand was applied by chemical method of alkaline fusion followed by grinding to 100 mesh and magnetic separation. Pre-oxidation was conducted prior to reduction and alkaline flux was added to coal based reduction system of in a rotary kiln. The alkali addition into the reduction system resulted to the formation of metallic iron and non metallic phases, in which sodium titanate compounds as nonmagnetic product can be separated from calcine using separator magnetic. XRD analyses of the concentrate and tailing as magnetic separation products showed concentrate was dominated by metallic phase compared to oxide phase and it doesn’t consisted iron-titan oxide and iron oxide. On the other hand, tailing was consisted iron-titan oxide and iron oxide.
Mechanical Properties and Decay Resistance of Wood Polymer Composites (WPC)
Authors: Rahman Md. Rezaur , Hamdan Sinin , Islam M. Saiful , Mondol Md. Shahjahan
Published: July 2011

In Malaysia, especially Borneo Island Sarawak has a large scale of tropical wood species. In this study, selected raw tropical wood species namely Artocarpus Elasticus, Artocarpus Rigidus, Xylopia Spp, Koompassia Malaccensis and Eugenia Spp were chemically treated with sodium meta periodate to convert them into wood polymer composites. Manufactured wood polymer composites were characterized using mechanical testing (modulus of elasticity (MOE), modulus of rupture (MOR), static Young’s modulus) and decay resistance test. Modulus of elasticity and modulus of rupture were calculated using three point bending test. Static Young’s modulus and decay resistance were calculated using compression parallel to gain test and natural laboratory decay test respectively. The manufactured wood polymer composites yielded higher modulus of elasticity, modulus of rupture and static Young’s modulus. Wood polymer composite had high resistant to decay exposure, while Eugenia Spp wood polymer composite had highly resistant compared to the other ones.
Machinability Improvement by Workpiece Preheating during End Milling AISI H13 Hardened Steel
Authors: Suhaily Mokhtar , Nurul Amin A.K.M. , Patwari Anayet Ullah
Published: July 2011

Surface finish and dimensional accuracy is one of the most important requirements in machining process. Inconel 718 has been widely used in the aerospace industries. High speed machining (HSM) is capable of producing parts that require little or no grinding/lapping operations within the required machining tolerances. In this study small diameter tools are used to achieve high rpm to facilitate the application of low values of feed and depths of cut to investigate better surface finish in high speed machining of Inconel 718. This paper describes mathematically the effect of cutting parameters on Surface roughness in high speed end milling of Inconel 718. The mathematical model for the surface roughness has been developed in terms of cutting speed, feed rate, and axial depth of cut using design of experiments and the response surface methodology (RSM). Central composite design was employed in developing the surface roughness models in relation to primary cutting parameters. Machining were performed using CNC Vertical Machining Center (VMC) with a HES510 high speed machining attachment in which using a 4mm solid carbide fluted flat end mill tool. Wyko NT1100 optical profiler was used to measure the definite machined surface for obtaining the surface roughness data. The predicted results are in good agreement with the experimental one and hence the model can be efficiently used to predict the surface roughness value with in the specified cutting conditions limit.
Multi-Criteria Optimization in End Milling of AISI D2 Hardened Steel Using Coated Carbide Inserts
Authors: Karim A.N. Mustafizul , Lajis Mohd Amri , Nurul Amin A.K.M.
Published: July 2011

This paper proposes a multi-criteria optimization technique using the mathematical models developed by the response surface methodology (RSM) for the target responses combined with desirability indices for the determining the optimum cutting parameters in end milling of AISI D2 hardened steels. Different responses may require different targets either being maximized or minimized. Simultaneous achievement of the optimized (maximum or minimum) values of all the responses is very unlikely. In machining operations tool life and volume metal removed are targeted to be maximized whereas the machined surface roughness need to be at minimum level. Models showing the combined effect of the three control factors such as cutting speed, feed, and depth of cut are developed. However, a particular combination of parameter levels appears to be optimum for a particular response but not for all. Thus adoption of the method of consecutive searches with higher desirability values is found to be appropriate. In this study the desirability index reaches to a maximum value of 0.889 after five consecutive solution searching. At this stage, the optimum values of machining parameters - cutting speed, depth of cut and feed were determined as 44.27 m/min, 0.61 mm, 0.065 mm/tooth respectively. Under this set condition of machining operations a surface roughness of 0.348 μm and volume material removal of 7.45 cm3 were the best results compared to the rest four set conditions. However, the tool life would be required to compromise slightly from the optimum value.
Evaluation on the Linear Viscoelastic Behaviors of Swelling Styrene-Butadiene-Styrene Block Copolymer
Authors: Huang Ling Ge , Wang Wan Jie , Tang Lin , Shi Zhi Gang , Cao Yan Xia , Wang Jing Wu
Published: July 2011

We choose petroleum ether and n-heptane as poor solvent and selective solvent to swell styrene-butadiene-styrene (SBS) and prepare a kind of swelling SBS sample with different swelling degrees. The steady rate sweep tests have been carried out and the steady zero shear viscosities have been obtained for two kinds of equilibrium swelling SBS. Furthermore, the dynamic frequency sweep tests have been performed for swelling SBS with different swelling degrees. The test results show that the curves of dynamic storage modulus (G’) is always located over those of dynamic loss modulus (G”), which exhibits that the viscoelastic behaviors of all the samples is charged by elasticity in the whole frequency range measured. The poor solvent give less destroy to the network structure of SBS than the selective solvent.
Preparation of (Mo,Nb)Si2 Ternary Alloys by Self−Propagating High−Temperature Synthesis
Authors: Feng Pei Zhong , Zhang Shuai , Wang Xiao Hong , Liu Wei Sheng , Wu Jie
Published: July 2011

An experimental study on the preparation of (Mo,Nb)Si2 ternary alloys was conducted by self-propagating high-temperature synthesis method from elemental powder compacts of different stoichiometries. And the combustion mode, combustion temperature, flame-front propagation velocity and product structure were discussed. The results show that (Mo,Nb)Si2 ternary alloys are characterized by an unsteady state combustion mode with a spiral−trajectory reaction front from top to bottom. The combustion temperature and flame−front propagation velocity decrease with the addition of coarse niobium powder. The combustion temperature and flame-front propagation velocity of MoSi2 are 1629K and 3.13mm/s respectively. However, those of (Mo0.8Nb0.2)Si2 alloy are 1460K and 1.97mm/s. The solid solubility of niobium in MoSi2 is less than 2.5at.%, and the combustion synthesis produce still remains Cllb single-phase structure in (Mo1-x,Nbx)Si2(x<0.075) sample. The C40-type structure appears in (Mo0.925,Nb0.075)Si2 compact and the intensity of diffraction peaks of C40-type phase gradually reinforces with the increase of niobium content. Combustion synthesis is an effective technology for producing (Mo,Nb)Si2 ternary alloys.
Fracture Mechanisms Anisotropy of AZ31 Magnesium Plate under Impact Loading Condition
Authors: Yang Yong Biao , Zhang Zhi Min , Wang Fu Chi
Published: July 2011

Dynamic mechanical properties of AZ31 magnesium alloy plate were carried out using split Hopkinson pressure bar (SHPB) with compression direction 0° and 90° from normal direction respectively. Optical microscopy (OM) and scanning electronic microscopy (SEM) were used for the observation of microstructure and fractograph. OM observations showed that cracks initiated and propagated along localized deformed bands consisted of twin intersection for 0° specimen, and that cracks initiated and propagated along localized transformed bands consisted of fine equiaxed dynamic recrystallized grains for 90° specimen. SEM observations showed that the fractograph exhibited typical ductile dimple fracture pattern for 0° and 90° specimens due to the thermal accumulation in localized bands caused by severe plastic deformation. The fracture mechanisms are anisotropic for AZ31 magnesium alloy plate, which contributed to the dynamic mechanical anisotropy of AZ31 magnesium alloy plate.
A Multiphase-Field Microstructure Numerical Simulation of AL-Cu Eutectic Alloy
Authors: Tang Jin Jun , Jiang Jian Zhong , Hou Li Qun , Chen Da Hui , Zhang Hua
Published: July 2011

In this paper, microstructure of AL-Cu eutectic alloy is simulated by improving Nestler’s multiphase-field model. The exact physical parameters are used in multiphase-field model, and obtained the steady calculational results. In this numerical calculation, AL and AL2Cu are regard as two independent components. The eutectic microstructure is regard as an admixture of single phase α (AL) and single phase θ (AL2Cu). Using the model, steady eutectic layered growth is simulated, and the simulated results agree well with the solidification theory. At the same time, the stochastic noise is introduced, and eutectic free layered growth microstructure is simulated. The microstructure of primary dendritic crystal and pseudoeutectic is also simulated by enlarging the calculational interval scale, and obtained a better result.
Microstructure and Mechanical Properties of Cold-Rolled TRIP Steel Sheets
Authors: Jing Cai Nian , Chen Xiao Hui , Wang Ming Gang , Tian Qi Zhong , Wang Zuo Cheng
Published: July 2011

Transformation induced plasticity (TRIP) steels have complex multiphase microstructure composed of ferrite, bainite and retained austenite [1]. These metastable retained austenite can transforms into martensite during plastic deformation, which generates a TRIP effect resulting in excellent combination of high strength and ductility even at high strength level [2-5]. For this reason, the TRIP-aided steel sheets are suitable to fabricate automobile parts, as they can offer excellent formability without sacrifice the strength and safety requirement of the steel sheets. As a result, the development of TRIP-aided steels has been a very important issue in the automobile field.
Phase Stability of Nb-Mo Alloys
Authors: Li Xiao Bo , Zhang Ping
Published: July 2011

The characteristic crystal model is applied to the study of phase stability and thermodynamics in substitutional bcc-based Nb-Mo alloys. The basic principle and method of alloy thermodynamics which is described by the characteristic crystal model is introduced in detail. The thermodynamic properties of the Nb-Mo system are evaluated to describe the Gibbs energies of various phases including both disordered and ordered phases. The phase diagram of Nb-Mo is assessed and predicted. The results are in good agreement with experiments. An unambiguous tendency toward order with a B2 superstructure in a broad range of alloy composition is predicted.
Study on the Radial Resistivity Variation of the Gas Doped Floating-Zone Single-Crystal Silicon
Authors: Zhang Xue Nan , Gao Shu Liang , Zhang Xu Guang , Li Jian Hong , Wang Yan Jun , Li Xiang , Shen Hao Ping , Wang Ji Hui
Published: July 2011

In this paper, the radial resistivity variation (RRV) of the gas doped floating-zone (GDFZ) silicon has been studied through of three factors that are the lower shaft rotation speed, the timeratio of the lower shaft clockwise(CW) rotation speed and the counterclockwise (CCW) rotation speed, and the eccentricity between the upper shaft and the lower shaft in the horizontal direction. Test results show that the lower shaft speed has greatly influenced the RRV of GDFZ silicon, and with the increase of the shaft speed, radial deviation of the resistivity decreases first and then increases. As the timeratio between the lower shaft of CW&CCW rotation speed increases, the single crystal radial resistivity distribution is improved. As reversible angle of CW&CCW further increasing, radial deviation of the resistivity distribution rises again. With the increases in eccentricity ing, resistivity variation between the edge and the center decreases, thus radial resistivity inhomogeneity of single crystal significantly is also reduced. Based on the above study, further optimization of process, reasonable regulation and control of shaft speed, reversible angle, eccentricity and other parameters selected during GDFZ process can be obtained, which would obtain good radial resistivity uniformity to meet the requirements of the semiconductor devices.
Preparation and Thermal Conductivity of Y2Ce2O7 Ceramic Material
Authors: Zhang Hong Song , Liao Su Ran , Yuan Wei , Guan Shao Kang
Published: July 2011

Y2Ce2O7 ceramic material was prepared by solid reaction at 1600°C for 10h. The phase composition, microstructure and thermal conductivity of this material were investigated. XRD results reveals that single phase Y2Ce2O7 with fluorite structure was synthesized. Microstructure of Y2Ce2O7 was dense and no other unreacted oxides or interphase existed in the interfaces between grains. Because of phonon scattering by oxygen vacancies and difference in atomic mass between substitutional atoms and host atoms, thermal conductivty of Y2Ce2O7 is lower than that of 8YSZ, which implies that this ceramic can be used as novel candidate materials for thermal barrier coatings in the future.
Grain Size Control and Ethanol Sensing Properties of Calcined SnO2 Nanoparticles
Authors: Wang Yu , Jia Xiao Lin , Dong Lin , Guan Shao Kang
Published: July 2011

SnO2 nanoparticles were prepared via a sol-gel method by heating the mixture of hydrous SnO2 nanoparticles and SiO2 nanospheres at 600 °C. The average particle size of the obtained SnO2 nanoparticles is 3.3 nm, smaller than that of the SnO2 nanoparticles (~ 6.4 nm) prepared by calcining the pure hydrous SnO2 at 600 °C. The SiO2 nanospheres play an important role in restricting SnO2 nanocrystal growth. The ~3.3 nm-sized SnO2 nanoparticles exhibited high sensitivity for ethanol as well as quick response and recovery time. The concentration detection limit can be as low as 5 ppm at room temperature.
Effect of Ni70Mn25Co5 or Fe55Ni29Co16 on the Growth of Type-II a Large Diamonds with Al as Nitrogen Getter
Authors: Li Shang Sheng , Luo Ning , Li Xiao Lei , Su Tai Chao , Zhou You Mou , Zhang Yi Shun , Jia Xiao Peng
Published: July 2011

With adopting Al as the nitrogen getter in Ni70Mn25Co5 or Fe55Ni29Co16 catalyst, High-quality type-Ⅱa large diamonds have been grown under the conditions of about 5.5GPa and 1580K by using the temperature gradient method. While Al(2.0wt%) is added in the Fe55Ni29Co16, the nitrogen concentration(Nc) in the diamond is less than 1ppm. While Al(4.0wt%) is added in the Ni70Mn25Co5, the Nc in the diamond is highly arrived at 48ppm. The different of solubility of nitrogen in both catalyst at high pressure and high temperature is the basic reason of the different effect of eliminating nitrogen of Al. It can be shown in experamentals that Al is a less efficient nitrogen getter in Ni70Mn25Co5 than in Fe55Ni29Co16. While Al(2.0wt%) is added in the Fe55Ni29Co16, the high-quality type-Ⅱa large diamond, in which nitrogen is less than 1ppm and which the size was arrived at 3.3mm, had grown by decreasing the growth rate of diamond.
Solvothermal Synthesis of Phase-Pure CuInS2 Hierachical Nanostructure Using Single-Source Molecular Precursor
Authors: Li Jing , Zhang Yong Cai , Zhang Ming
Published: July 2011

The synthesis of phase-pure CuInS2 microclusters comprising nanoflakes was achieved by solvothermal treatment of copper indium diethyldithiocarbamates (compositionally CuIn-(DDTC)5) in ethanol at 190 °C for 36 h. The obtained product was characterized by X-ray diffraction, Raman, energy dispersive X-ray spectroscopy and field emission scanning electron microscopy. Besides, contrast synthesis tests using multi-source precursors were also conducted.
Lifelong E-Learning and Individual Characteristics: The Role of Gender, Age, Career and Prior Experience
Authors: Liao Hsiu Li , Liu Su Houn , Chou You Jie
Published: July 2011

Lifelong learning is a term recognized that learning is not confined to childhood or the classroom, but takes place throughout life and in a range of situations. Compare to the continuous growth of the e-learning market for the lifelong learning of adults, there are relatively few studies are available on the learning behaviors of these learners on the e-learning website. In this study, TAM and TPB theory were integrated and employed to examine the relationships between courses or systems and perception constructs. The degree of learners’ perceptions of interaction with others don’t influence course flexibility, ease of use, and behavioral control learners’ perceived. Different gender and career of learners don’t influence all constructs. Younger learners perceived that they can interact with teachers and other learners as well as learn more on the e-learning website. The e-learning experiences of learners are significantly associated with system functionality, system response, and perceived behavioral control.
Study on Piezoelectric Stacked Generator
Authors: Lin Wei , Li Zhe , Chen Wen , Zhou Jing
Published: July 2011

A piezoelectric generator based on the piezoelectric stacked elements is applied to realize electro- mechanical energy conversion in this paper. The piezoelectric stacked generator is constructed. The relational expression about output electrical characteristic parameters, the constructional dimension parameters of piezoelectric stack elements and external driving forces is discussed here. Theoretical predictions confirmed by experimental results show that the piezoelectric generator produces electrical power with higher efficiency, and energy harvesting circuit can harvest energy from the piezoelectric generator effectively.
Efficient Mobile Anchor Point Messaging Assumption in IPv6 Based Wireless Mobile Networks
Authors: Park Byung Joo , Alisherov Farkhod A. , Chang Byeong Yun
Published: July 2011

Using a hierarchy that differentiates local mobility from global mobility is more appropriate to the Internet because it improves handoff performance, minimizes the loss of packets that may occur during transition and significantly reduces the mobility management signaling load on the Internet. But the only disadvantage of the Hierarchical Mobile IPv6 is that Mobility Anchor Point are sometimes "far away" and there is too much signaling from the mobile node. This paper assumes a new messaging architecture for the Hierarchical Mobile IPv6, which can shorten the signaling from the mobile node and minimize the handoff latency.
Far Field Noise Suppression Method in McWiLL Intercom Based on Double Uni-Directional Microphone
Authors: Zhang Yu Hua , Jia Li Min , Li Zhong
Published: July 2011

To satisfy McWiLL communication requirement in noisy environment, a far field noise suppression method based on double uni-direction microphone in McWiLL intercom was studied. The method arranges two uni-direction microphones rationally and uses analog noise cancelling processor to accomplish surrounding noise reduction in McWiLL intercom in noisy environment. To verify validity of the method, several contrast experiments using diagnostic rhyme test method were done. Experiments results show that the far field noise suppression method based on double uni-direction microphone is effective for surrounding noise reduction.
Application of Rough Set Feature Selection in the Hazard Assessment of Debris Flow
Authors: Li Ju , Chang Jin Yi , Wang Xing , Wu Xiao Biao
Published: July 2011

In this thesis, the risk of debris flow have been studied. And it used feature selection based on rough set to construct debris flow hazard assessment model.The innovation of this thesis is:the on the basis of without losing effective information,it greatly simplified the evaluation process,the debris flow hazard assessment which is gotten by the research methods results consistent with the geological prototyping.
A Passive Circuit Based RF Optimization Methodology for Wireless Sensor Network Nodes
Authors: Zheng Li Qiang , Mathewson Alan , O'Flynn Brendan , Hayes Michael , O'Mathuna Cian
Published: July 2011

Return loss of wireless sensor network (WSN) node indicates the impedance matching between signal ports of the RF chip and the antenna, and thus shows the transmission efficiency in the signal path. All circuit components, including capacitors, inductors, PCB tracks, packaging parasitic and RF ports were modeled as equivalent passives, to achieve accurate simulation result of return loss of the WSN node. An optimization methodology of return loss was proposed based on the parameter sweep of the equivalent passive network simulation. With the help of the methodology, some critical components’ values were changed to obtain optimized RF performance for the wireless node. Measurements matched the analysis and simulation well and showed great improvement.
Research on Technology of Medical Image Database and its Connection with HIS Database
Authors: Zhang Xiao Lin , Wang Wan Li , Lv Xiao Qi
Published: July 2011

Medical digital image information storage standard and existing heterogeneous database technology were analyzed with view to the particularity of the standard for medical images; data in medical images were organized according to data organizational hierarchy in the DICOM standard and sophisticated relational databases were utilized to store medical images. Using XML as a middleware to connect medical image database to HIS and then through relational databases and XML transformation rules to complete the conversion of the two databases into XML document. The study indicated that the method is able to achieve the purpose of the connection of heterogeneous databases.
Train Mode Research of Software Outsourcing Talents
Authors: Cui Wei , Liu Yang , Lin Yan , Qian Si Yu , Ye Jia , Yang Hai Feng , Li Ya Jun
Published: July 2011

It analyzed Chinese talent demand character and present training problems in software outsourcing. Detail training mode was discussed. This work introduced detail specialties and relevant superiorities (shortcomings) of several different software talent training mode. Practical training based on realistic enterprise case and composite language studying was concluded .
Research on Tourism United Marketing in Turpan Area, Xinjiang, China
Authors: Li Yong , Sun Hao Jie
Published: July 2011

Endowed by nature, Turpan in Xinjiang, China enjoys rich tourism resources. Since the united marketing company for Turpan area was founded in 2007, tourism has been greatly improved. Proceeding from the tourism resources of Turpan and the background of united marketing, combined with the development conditions of recent years, this text analyzes the main problems of Turpan united marketing and proposes up the countermeasures, aiming to provide theoretical and practical guidance for tourism sustainable development.
A Study on Pen-Based Input Operation and Tilt Angle of Tablet
Authors: Bao Dong Xing , Li Xiao Ming , Xin Yi Zhong , Ren Xiang Shi
Published: July 2011

In this paper, we designed two experiments that can be used to investigate: 1) whether pen-based input operation can be affected by tilt angle of tablet; 2) at which tilt angle of tablet can user do pen-based input operation with comfort, quickness, and accuracy. The experiments include pointing tasks (1-dimensional and 2-dimensional) based on Fitts’ law and stroking tasks (linear and circle) based on Steering law. Each task would be done under 5 kinds of tilt angle of tablet: 0, 15, 30, 45, and 60 degrees.
An Analysis of the Strategy of Product Platform
Authors: Wu Ai Hua , Li Tian Fu
Published: July 2011

Product platform is a set of subsystems and interfaces that form a common structure from which a stream of related products can be efficiently developed and produced. Core capability is a key driver for successful product platform development and core technology is the basis of all competitive strategies for high-tech enterprises and their products, and the core products supported by it is the physical embodiment of core competence.
An Effective Intrusion Detection Model Based on Random Forest and Neural Networks
Authors: Zhong Shao Hong , Huang Hua Jun , Chen Ai Bin
Published: July 2011

This document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.Intrusion detection is a very important research domain in network security. Current intrusion detection systems (IDS) especially NIDS (Network Intrusion Detection System) examine all data features to detect intrusions. Also, many machine learning and data mining methods are utilized to fulfill intrusion detection tasks. This paper proposes an effective intrusion detection model that is computationally efficient and effective based on Random Forest based feature selection approach and Neural Networks (NN) model. We firstly utilize random forest method to select the most important features to eliminate the insignificant and/or useless inputs leads to a simplification of the problem, in order to faster and more accurate detection; Secondly, classic NN model is used to learn and detect intrusions using the selected important features. Experimental results on the well-known KDD 1999 dataset demonstrate the proposed hybrid model is actually effective.
Error Estimation for a Economic Equilibrium Modeling
Authors: Wang Lei
Published: July 2011

In this paper, the global error estimation for the generalized linear complementarity problem in economic equilibrium modeling(GLCP) is established. The result obtained in this paper can be viewed as extensions of previously known results.
Slip Pridiction Based Path Planning for Planetary Rovers
Authors: Zhou Lan Feng
Published: July 2011

Most methods of path planning for planetary rovers were designed for fairly benign terrain and do not account for potential slippage . Though the TANav system addresses slip prediction issue,it does not integrate directional slip prediction into the path planning algorithm.This paper presents an autonomous navigation algorithm for planetary rover based on slip pridiction. This method does integrate directional slip prediction into the path planning algorithm resolving the essue of emerging higher-level behaviors such as planning a path with switch-backs up a slope. The result of simulation demonstrates that this method is effective.