bluuebunny/crossref_metadata_2025 huggingface dataset:
A 3-D Forming Prediction Method of Increase of Sheet Thickness during Drawing Process
Authors: Kotani Yuji , Watanabe Akihiro , Nishiumura Kazuki , Watari Hisaki
Published: July 2011

To lighten total product weights, the local increases in sheet thickness of products effectively contribute to decreasing product weights, when appropriate sheet thickness distribution in product by a designer could be performed by using an accurate prediction method by simulation. The designer only could distribute thick part where needed a large moment inertia of area from the view points of the strength of the section. In the sense of the such optical designing for the variable thickness distribution in the products, we do not need to consider that sheet thickness should be constant in a product. This paper is concerned with a forming prediction during deep drawing process. To clarify the mechanism of increase of sheet thickness, a 3-D forming simulation during deep drawing by finite element method was performed. Effects of tool shapes (contacting angles to the original materials, contacting length of punch with a material) which mainly affects the results on thickness change of original materials were investigated. The thickness distribution of drawn cups was measured in order to compare simulation results obtained by the finite element method. It has been found that controlling sheet thickness distribution was possible if an original material was relatively thick, when in choosing an appropriate manufacturing condition could be selected.
The Effect of Cooling Rate on Mechanical Properties of 22MnB5 Steel Sheet during Hot Press Forming
Authors: Kwon Ki Young , Kim Nak Hyun , Kang Chung Gil
Published: July 2011

There has been a growing usage of high strength steels (HSS), particularly in automobile applications mainly as structural parts in view of their light weight and high strength properties. These materials are also being considered for dynamic applications. However, the multi-phase microstructure, which is at the base of the strengthening mechanisms in most of these steels, leads to unacceptably high stresses during forming and significant springback phenomena, thus making traditional sheet metal forming technologies unsuitable. To avoid the disadvantages, a new process method was introduced – Hot Press Forming. Hot press forming (HPF) process is a forming method which can provide various advantages such as excellent mechanical properties and formability, good weldability and little springback. Here, the experiment parameters which include locations of the cooling holes and the flow rate of the cooling water play an important role in the HPF process. In this paper, the Al-Si coated boron steel sheet was researched by heating it up to 930oC for 5 min and formed by a hydraulic press. In this study, microstructural evolutions and the associated mechanical properties were investigated in terms of the flow rates of the cooling water.
Numerical Simulation of Welding Sequence Effect on Temperature Distribution, Residual Stresses and Distortions of T-Joint Fillet Welds
Authors: Syahroni N. , Hidayat M.I.P.
Published: July 2011

Welding sequence is one important factor which affects the residual stresses and distortions produced during welding, thus determines the welding quality and performance. In this paper, 3D numerical simulation of temperature distribution, residual stresses and distortions of the T-joint fillet weld with respect to the variation of welding sequence is presented. The finite element simulation involved thermo-mechanical analyses. Four welding sequences (WS) considered are one direction welding (WS-1), contrary direction welding (WS-2), welding from centre of one side (WS-3) and welding from centres of two sides (WS-4). The simulation results revealed that peak temperature achieved in the welding was greatly affected by the welding sequence and residual stress and angular distortion produced cannot both hold in minimum for a WS. The smallest residual stresses and the smallest angular distortions are related respectively to WS-2 and WS-4. The distributions of temperature, longitudinal and transverse residual stresses as well as angular distortions were also presented.
Effect of Deformation Temperature on Deformation Behavior and Service Performance of 7050 Aluminum Alloy
Authors: Wang Xin Yun , Hu Hui E , Xia Ju Chen
Published: July 2011

Compression tests of 7050 aluminum alloy have been conducted at different temperatures (340, 380, 420, and 460 °C) with strain rate of 0.1 s-1. The deformation behavior and service performance of the alloy are investigated using EBSD technique, TEM and hardness measurement. Results show that the volume fraction of recrystallized grains increases with the increase of deformation temperature. The primary softening mechanisms of the alloy deformed at 340, 380, and 420 °C are dynamic recovery, and dynamic recrystallization is the main softening mechanism of the alloy deformed at 460 °C. The hardness of the 7050 aluminum alloy deformed increases with increasing deformation temperature. Dynamic precipitation appears when the 7050 aluminum alloy was deformed at 340, 380, and 420 °C, and strengthening mechanisms include mechanical hardening and precipitation strengthening. When deformation temperature is 460 °C, solid solution strengthening and grain boundary strengthening are primary strengthening mechanisms.
On-Line Empirical Models for Control of Bead Geometry in Robotic Arc Welding Process
Authors: Son Joon Sik , Kim Il Soo , Kim H.H. , Na H.H. , Lee J.H.
Published: July 2011

Recently, not only robotic welders have replaced human welders in many welding applications, but also reasonable seam tracking systems are commercially available. However, fully adequate process control systems have not been developed due to a lack of reliable sensors and mathematical models that correlate welding parameters to the bead geometry for the automated welding process. Especially, real-time quality control in automated welding process is an important factor contributing to higher productivity, lower costs and greater reliability of the bead geometry. In this paper, on-line empirical models with experimental results are proposed in order to be applicable for the prediction of bead geometry. For development of the proposed predicting model, an attempt has been made to apply for a several methods. For the more accurate prediction, the prediction variables are first used to the surface temperatures measured using infrared thermometers with the welding parameters (welding current, arc voltage, CTWD and gas flow rate) because the surface temperature are strongly related to the formation of the bead geometry. And the developed model has been carried out a learning each time data acquired.
Effect of Energy Input on Microstructure and Hardness of TIG Welded AISI 430-Ferritic Stainless Steel
Authors: Amuda M.O.H. , Mridha S.
Published: July 2011

Studies on the weldability of ferritic stainless steel grades suggests that low heat input rate and better heat transfer dynamics are appropriate for the control of grain size and microstructural feature in thin sections. However, the optimal welding conditions to achieve combination of such characteristics are yet to be established. In the present investigation, AISI 430 ferritic stainless steel is TIG welded using energy input between 0.205 and 2.05kj/mm and characterized in terms of microstructure and hardness. The microstructural characterization of the welds with varying heat input rates suggests the presence of interdendritic martensite in the fusion zone and grain boundary martensite in the HAZ in conjunction with some intermetallics in varying proportion. The hardness values across the welds indicate that grain growth and the presence of intermetallics are minimized when welded with increased heat input rates that permits transformation within the dual phase regions. The study provided a new insight into the contribution of heat input rate in the production of unwanted weld microstructural features and assisted in the design of methods and techniques for tailoring weld microstructures with optimum properties.
Effect of Work Piece Dimensions on Cost Effective Hybrid Rapid Casting Solution for Aluminium Alloy
Authors: Singh Rupinder , Singh Rupinder
Published: July 2011

The purpose of the present experimental investigations is to study the effect of work piece dimensions on reducing the shell wall thickness of mould cavity for cost effective, hybrid rapid casting solution of aluminum alloy. Starting from the identification of component/benchmark, technological prototypes with three different work piece dimensions (volume/ weight) were produced, at different shell wall thickness of mould cavity using hybrid rapid prototyping technique (combination of three dimensional printing and conventional sand casting). Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the castings produced. Some important mechanical properties were also compared to verify the suitability of the castings. The study suggested that the shell wall thickness, having value less than the recommended one is more suitable from dimensional accuracy and economic point of view, for all three work piece dimensions (volume/ weight). Further best shell wall thickness of the mould cavity for different work piece dimensions of the selected benchmark has been highlighted for rapid casting solution of aluminum alloy.
The Effects of Isothermal Temperature on the Microstructure of Semisolid A6070 Alloy Produced by SIMA Process
Authors: Karshenas M. , Emamy M. , Fadaei E.
Published: July 2011

The effects of isothermal temperature on the microstructure evolution of semisolid A6070 alloy produced by strain-induced melt activation process were investigated. The results showed that high semisolid isothermal temperature could make the semisolid particles more globular, but the size of the particles would grow larger and accelerate the spherical evolution of the solid particles. It was found that the optimal process temperature should be 620 °C and 10 min of isothermal temperature based on the conditions of this paper.
The Effects of Cooling Slope Casting and Isothermal Treatment on Wear Behavior of A380 Alloy
Authors: Saklakoğlu Nurşen , Gencalp S. , Kasman Şefika
Published: July 2011

In this study, A380 aluminum alloy feedstock produced with cooling slope casting was exposed to isothermal treatment to obtain a globular microstructure which is a key feature for semisolid forming. The dendritic primary phase in the conventionally cast A380 alloy has readily transformed into a non-dendritic one in ingots cast over a cooling plate from pouring temperatures between 615, 630 and 650 °C. After the casting process, isothermal treatment was carried out at 565 °C in induction unit. Isothermal treatment yields a globular microstructure. To determine the tribological properties of this alloy, a pin-on-disc tribometer was used to carry out tribological tests under dry sliding conditions. The results showed that both cooling slope casting and isothermal treatment has an effect on tribological properties.
Laser Gas Assisted Nitriding and TiN Coating of Ti-6Al-4V Alloy
Authors: Al-Mana O. , Hashmi M.S.J. , Yilbas Bekir Sami
Published: July 2011

Laser gas assisted nitriding and TiN coating of Ti-6Al-4V alloy is carried out. The microstructures developed in the laser irradiated region are examined using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD). The laser nitrided surfaces are coated with TiN using the PVD facility to enhance the tribological properties. The heating model incorporating the lump parameter analysis is used to predict the melt layer thickness during the laser treatment process. It is found that laser nitrided surfaces posses δ-TiN+ε-TiN phases and TiN coating of laser nitrided surfaces improves the microhardness at the surface.
Influence of Moisture Absorption on Impact Strength and Failure Behavior of Hybrid Jute-Carbon/ Epoxy Composite
Authors: Lenda T.A. , Mridha S.
Published: July 2011

Hybrid jute-carbon/ epoxy composites, fabricated by hand lay-up method with fiber volume fractions of 0.47, 0.58 and 0.68 were used to investigate water absorption behavior as a function of immersion time and fiber content. The effect of moisture content on impact strength and failure modes was also studied. Results show that the moisture absorption increased with increasing the immersion time in water and it was more with higher fiber fraction specimens. Maximum moisture contents of 0.45%, 0.52% and 0.61% were recorded for the specimens containing fiber volume fractions of 0.47, 0.58 and 0.68, respectively. The impact strength reduced with increasing moisture absorption in all specimens containing different fiber fractions. Composites with higher fiber content gave reduced impact strength under all test conditions. Composites of different fiber fractions and of highest moisture content produced impact strengths about 20 to 28% less than those strengths obtained without water immersion. The 47 vol% fiber specimen was least affected by water immersion and impact strength reduction was only 17% after immersion till saturation. Failure occurred by mainly by delamination and it was evident in all fractured specimens. Results of the effect of impact energy on moisture content have been evaluated using ANOVA ANALYSIS and the results gave errors of 1%, 0.6 % and 0.8 % for 0.47, 0.58 and 0.68 fiber volume fraction specimens, respectively.
Influence of Heat Treatment on Properties of Hot Isostatically Pressed Turbine Blade Superalloy IN738
Authors: Farahany Saeed , Aghaie-Khafri M. , Ourdjini Ali , Idris Mohd Hasbullah
Published: July 2011

Impact of heat treatment on hot isostatically pressed (HIP) Ni-base superalloy has been investigated before and after conducting HIP process. HIP was performed by applying a stress of 120 MPa at a temperature of 1200 °C for 2 hours under argon atmosphere followed by furnace cooling to room temperature. Heat treatment cycle was conducted on the samples according to GEB50A563. Microstructural observation demonstrated the deleterious change of  morphology after HIP process which causes to decrease of hardness and creep strength. However, pre heat treatment in compared with cast specimen show slight changes in microstructure but, post heat treatment can revert this change of  morphology completely and also increase the mechanical properties.
Sm-Doped NiFe Thin Films: Structural and Magnetic Characterization
Authors: Gandhi Abbasi A. , Rahman I.Z. , Mousavi M.V.K. , Rahman M.A.
Published: July 2011

This paper reports on the effect of Sm doping concentration on structural and static magnetic properties of electrodeposited NiFe thin films. A reduction of Ni concentration from 80 to 50 percent was observed as the Sm concentration increased from 0 to 25%. XRD analyses revealed that a transition from crystalline to partially disordered state occurred on the Sm-doped NiFe thin films and ultimately transformed to amorphous state at higher concentration. The saturation magnetization decreased to ~50% at 25% Sm doping as compared to that of NiFe thin films.
Microstructural and Magnetic Studies on Calcined Ni-Zn Ferrite Powders Prepared by Chemical Co-Precipitation Method
Authors: Rahman I.Z. , Ahmed T.T.
Published: July 2011

In this paper, we report on structural and magnetic properties of NiZn ferrite powders prepared by chemical co-precipitation method and calcined at different temperatures. Structural, topological and compositional analyses were performed by XRD, SEM, AFM and EDX techniques. The cation distributions in Ni0.8Zn0.2Fe2O4 ferrites were investigated by XPS (Al K radiation: h=1486.6 eV). Particle sizes were measured using AFM techniques and results were compared with BET technique and magnetic measurements were carried out using a vibrating sample magnetometer at room temperature.
Study on the Formability of Magnesium Alloy for Bearing Cover with Inner Cavity under Hot Forging
Authors: Ho Huey Lin , Hsiang Su Hai , Wang Pao Te
Published: July 2011

This study investigates the formability of AZ31 magnesium alloy for bearing cover with inner cavity under hot forging. Firstly high speed metal test machine of China steel Co. Ltd. is used to carry out the compression tests under different forming temperatures and strain rates to obtain the stress-strain curves. Then, the stress-strain data obtained from compression test under different dies are applied to analyze the formability of magnesium alloy for bearing cover of the car under forging by commercial package DEFORM. Besides, hot forgings of magnesium alloy for bearing cover are carried out to study the formability of magnesium alloy, and to find the best forging condition. Meanwhile, from the measured result of hardness and metallographic observation of forged part, the influence of forming temperatures on the strength and microstructure of magnesium alloy under forging of bearing cover are evaluated. Finally, the Artificial Neural Network (ANN) is applied to learn the data obtained from experiments and to predict the experimental result under new combination of process parameters. Also, confirmatory experiment is carried out to prove the usefulness of the ANN model.
Effect of AlCl3 Addition in Processing of TiAl-Al2O3 Nano-Composite via Mechanical Alloying
Authors: Alamolhoda S. , Heshmati-Manesh Saeed , Ataie Abolghasem , Badiei A.
Published: July 2011

In this paper, effect of AlCl3 addition as process control agent (PCA) during high energy ball milling of Al and TiO2 powder mixture was studied. This mechanical activation is aimed at to synthesize an ultra fine grained TiAl/Al2O3 composite. Experimental results show that AlCl3 significantly prevents severe cold welding of Al particles to milling media. Sublimation of this compound by local temperature increase due to balls collisions seems to be the main reason in prevention of severe cold welding. Samples were characterized by XRD, SEM and DTA. Mean crystallite sizes in particles of this sample and those milled with no PCA and milled with stearic acid were calculated and the results showed that smaller crystallite size is obtained in presence of AlCl3. However, DTA results revealed that addition of AlCl3, shifts aluminothermic reduction of TiO2 by Al to higher temperatures and therefore, final composite phases form at higher temperatures. Phase evolutions during further heat treatment of the powder sample milled with AlCl3 were also thoroughly studied.
FEA Based Fatigue Life Estimation of Automotive Component Correlated with Fatigue Data Editing Technique
Authors: Kadhim Nawar A. , Abdullah Shahrum , Ariffin Ahmad Kamal , Bedan S.M.
Published: July 2011

A computational approach based on finite element analysis (FEA) for integrated durability assessment in an automotive component is presented. For further time saving related durability evaluation, the objective of this research is to investigate how accurately a road data history can be edited. A road data has been collected using a fatigue data acquisition system. A substantial compression for automotive lower suspension arm fatigue damage was performed for the purpose of accelerated fatigue data analysis. FEA was then used to estimate the fatigue life for the original and the edited data using two different strain life models. The original road data has been successfully edited for the purpose of damage predicting using FEA with a big difference in the software spending time for the component fatigue life prediction. As a result, the editing method was shown to be useful for summarising long histories and resulting in significantly shorter analysis with presenting the predicted amount of the fatigue damage as the original histories. As a consequence of application for automotive lower suspension arm, this technique can be applied in performing a fatigue history editing, especially in compression of data set.
Impact Properties of Natural Fiber Hybrid Reinforced Epoxy Composites
Authors: Jawaid Mohammad , Abdul Khalil H.P.S. , Bhat A.H. , Abu Baker A.
Published: July 2011

The hybrid composites were fabricated by taking cheaply available empty fruit bunch fibers and jute fibers trilayers as reinforcement in epoxy matrix using simple hand lay-up-technique. Thermal, mechanical and morphological properties were characterized. The notched izod impact strength of most hybrids increased with respect to the virgin matrix. The laminates coupled with 2-Hydoxy ethyl acrylate (HEA) showed better impact properties than the one without coupling agent. The addition of fibers and coupling agent considerably improved the thermal stability (i.e., decomposition and residue content) of the hybrids. The thermal properties measured by thermogravimetric analysis (TGA) showed that fibres and coupling agents improved thermal properties. The impact fractured composite specimens were analyzed using field emission scanning electron microscopy (FESEM) to know the morphological behaviour.
Fatigue Behavior and Damage Mechanism of a Cast Aluminum Alloy in Very High Cycle Regime
Authors: Xue Hong Qian , Bayraktar E. , Bathias Claude
Published: July 2011

An improved understanding of fatigue behavior of a cast aluminum alloy (2-AS5U3G-Y35) in very high cycle regime was developed through ultrasonic fatigue test in axial and torsion loading, cyclic loading in axial and torsion at 35 Hz and 20kHz with R=-1 was used respectively to demonstrate the effect of loading condition. S-N curves obtained show that fatigue failure occurred in range of 105 -1010 cycles in axial or torsion loading, the asymptote of S-N curve is inclined gently, but no fatigue limit under torsion and axial loading condition. Fatigue fracture surface shows fatigue crack essentially initiated from the surface of the specimens subjected to cyclic torsion load, it is different from the fatigue fracture characteristic in axial loading which fatigue crack initiate from subsurface defect in very high cycle regime. Fatigue initiation is on the maximum shear plane, the overall crack orientation is observed on a typical spiral 45° to the fracture plane, which is the maximum principle stress plane, however, shear strip are very clear in the torsion fatigue fracture surface, the torsion fracture is actually in shear fracture.
Evaluation of Friction Welded Bi-Material Joint Strength Subjected to Impact Loads
Authors: Qasim H. Shah , Kassim A. Abdullah
Published: July 2011

In the present work the bond strength of two friction welded polymers was investigated when the bimaterial specimens were subjected to projectile impact at 86 ms-1. Two transparent polymer rods of Polycarbonate(PC) and Polymethylmethacrylate Acrylic(PMMA) were joined together using rotary friction welding. Specimens were cut into two different batches. In one batch the central portion of the rod specimens were removed and in the other batch the complete specimens along with their central portion were retained. When the bi-material specimens were subjected to projectile impact the cracks initiated in the comparatively brittle PMMA specimens and were able to propagate across the interface and subsequently into the PC specimen for the first batch of the specimens while the cracks were either arrested at the bi-material interface or the cracks propagated along the interface in the second batch of specimens. From the experimental work it was deduced that the crack propagation along the interface or across the interface could be a good measure of the bond strength difference of a bi-material joined using rotary friction welding process. Weak point of rotary friction welding has also been identified.
Controlled Potential Electrodeposition and Characterization of ZnTe Thin Films on Indium Tin Oxides
Authors: Mohamad S.A. , Basirun Wan Jeffrey , Ibrahim Z.A. , Arof A.K. , Ebadi Mehdi
Published: July 2011

Electrodeposition of ZnTe thin films by controlled potential method from aqueous solutions on ITO were done to investigate characteristics suitable as a window material in solar cells technology. The influence deposition of potential towards the Zn:Te ratio and the crystallinity are discussed. The electrodeposited films were investigated by using X-Ray Diffraction and Energy Dispersive Analysis of X-Ray. The Te content decreases at higher deposition potentials.
Egg Yolk as Pore Creating Agent to Produce Porous Tri-Calcium Phosphate for Bone Implant Application
Authors: Fariza A.R. , Zuraida A. , Sopyan Iis
Published: July 2011

Porous tri-calcium phosphate which is to be applied as artificial bone was prepared via protein consolidation method and egg yolk is used to give binding effect as well as to create porosity. In this experiment, fractions of egg yolk is controlled from 50 wt%, 60 wt%, 70wt% and 80 wt% and the mixture of egg yolk and tri-calcium phosphate powder were dried at 60 °C before undergone uniaxial compaction method. Subsequently, pressure of 68.5 MPa is given to the mold to produce cylindrical shape samples with diameter to height ratio of 1:2. Samples were then sintered at 1100°C to achieve porous tri-calcium phosphate. This method produces porous tri-calcium phosphate with desired porosity of 20-54.5% and acceptable compressive strength between 0.7-0.07 MPa. Besides, microporosity of 0.4-1μm and macroporosity in the range of 100-800μm were successfully obtained from this method.
Effects of Strontium and Calcium on the Microstructure and Grain Size of Cast AZ91 Magnesium Alloy
Authors: Kiani A. , Emamy M. , Fadaei E. , Ghannadi Saber
Published: July 2011

The experiments focused on the influence of strontium and calcium as additional alloying elements on the grain size and phase distribution of AZ91 magnesium alloys. For this purpose, different concentrations of Sr (0.01, 0.1, 0.4, and 0.8) and Ca (0.01, 0.1, 0.4, 0.6 and 0.78) were added. The microsturctural examination of specimens was made by an optical microscope and scanning electron microscope. From obtained results it was found that using 0.4 wt% strontium can provide a fine and uniform structure.
Experimental Investigation of Machining Parameters on Surface Roughness in Dry and Wet Wire-Electrical Discharge Machining
Authors: Abdulkareem Suleiman , Khan Ahsan Ali , Zain Zakaria Mohd
Published: July 2011

Wire electrical discharge machining (WEDM) is a thermal process in which the workpiece and the wire (tool) experience an intense local heating in the discharge channel. The high power density results in the erosion of a part of the material from both electrodes by local melting and vaporization. Whilst good surface finish and high material removal rate of the workpiece is a major requirement, the effect of EDM machining factors on these requirements cannot be overlooked. This study investigate the effect of two different machining methods of dry and wet WEDM process as well as the effect of on-time and voltage on the surface roughness of the workpiece. The machining factors used for this study are the pulse current, on-time and voltage. The results of the effect of the two machining methods on the responses are investigated and reported in this paper.
Experimental Investigation on the Instability of Al Sheet in Hydraulic Bulging Based on ESPI
Authors: Liu Yan , Wang Zhong Jin
Published: July 2011

Electronic speckle pattern interferometry (ESPI) was applied to hydraulic bulging to analyze the entire deformation process, especially the instability evolution of Al 1060 sheet. Speckle patterns of the specimens were captured continuously to record the deformation fields. The development of full-field strain rate during bulging was represented by the fringe patterns real-timely. The emergence of the defect and its subsequent transformation into groove and crack were revealed clearly by the aberration region in the fringe patterns. The onset of diffuse necking and localized necking were determined by the strain rate distribution curves calculated based on the fringe patterns. Results indicate that ESPI is a satisfying method to analyze the instability and fracture of sheet metals even in three dimension deformation. The growth of micro-crack caused a banded weak region. Diffuse necking occurred in the weak region due to strain localization. A groove generated in the banded weak region and then extended along the length direction. The remarkable strain localization in the groove indicated the onset of localized necking. The thickness of the groove decreased quickly and finally caused fracture. The accurately and quickly determined necking strains would lead to a safer FLD.
Functionalized Conjugated Polymer/ZnO Nanocomposite: Synthesis and Characterization
Authors: Gupta Bhavana , Kumar Ashish , Sundar Vignesh , Prakash Rajiv
Published: July 2011

Functionalized conjugated polymer polyanthranilic acid (PANA)/zinc oxide (ZnO) nanocomposite has been formed using co-precipitation method followed by control heating. Carboxyl functionalized polymer PANA is chemically formed in aqueous solution at acid pH and ZnO nanoparticles is formed by hydroxide precipitation at basic pH followed by control heating. A homogeneous PANA-ZnO nanocomposite is formed by co-precipitating polymer at acidic pH followed by Zn(OH)2 precipitation by increasing pH in PANA matrix and by control heating. Resulting nanocomposite is characterized under XRD, UV-vis, FT-IR, SEM and TEM techniques. Nanocomposite is heated at various temperatures (35-600oC) and characterized using XRD for observation of formation of pure ZnO phase in polymer matrix. Pronounced amorphous behavior of nanocomposite below 100oC is observed due to characteristic amorphous nature of conjugated polymer and probably complexation of Zn2+ with carboxyl functional groups (-COO-) of polymer rather than formation of pure phase of ZnO. However, above 250oC composite shows some crystalline nature. The crystallinity is explained on basis of decomposition of carboxyl functional groups of the polymer (above 250oC) therefore decomposition of polymer zinc ions complexes and formation of polymer chains with lesser number of carboxylic groups (like polyaniline) with new arrangements and formation of ZnO nanoparticles. When the sample is heated up to 600°C highly crystalline character of the composite supported almost pure ZnO phase formation with little amorphous character due to remaining polymers. Co-precipitation technique shows the formation of uniform nanocomposite and better interaction of the two components with core shell structure, which is further supported by HRTEM.
Determination of the Constants of Zerilli-Armstrong Constitutive Relation Using Genetic Algorithm
Authors: Majzoobi G.H. , Khosroshahi S. Faraj Zadeh , Mohammadloo H. Beik
Published: July 2011

Identification of the constants of material models is always a concern. In the present work, a combined experimental, numerical and optimization technique is employed to determine the constants of Zerilli-Armstrong model. The experiments are conducted on a compressive Hopkinson bar, the simulations are performed using finite element method and optimization is carried out using genetic algorithm. In the method adopted here, there is no need for experimental stress-strain curve which is always accompanied by restricting phenomenon such as necking in tension and bulging in compression. Instead of stress-strain curve, the difference between the post-deformation profiles of specimens obtained from experiment and the numerical simulations is adopted as the objective function for optimization purposes. The results suggest that the approach introduced in this work can substitute costly instrumentations normally needed for obtaining stress-strain curves at high strain rates and elevated temperature.
Mechanical Properties Modification of Polyethylene (PE) for CaCO3 Particulated Composites
Authors: Sivarao  , Salleh Mohd Rizal , Kamely A. , Tajul A. , Taufik
Published: July 2011

Calcium carbonate (CaCO3) is one of the most useful and versatile materials known to man. In this research, eggshell as a natural composite bioceramics was used to modify and improve the mechanical properties of an existing polyethylene which is widely used to manufacture daily goods by small medium industries in Malaysia. Chicken eggshell containing 95% Calcium Carbonate is highly potential to be used as bio-filler to improve poly-based matrix in improving their performance behavior. PE was chosen for this project to modify its virgin mechanical properties by reinforcing eggshell/calcium carbonate and later investigate its character to improve the current product’s performance. Tensile, creep and flexural tests were carried out to characterize the developed PE-CaCO3 composites. Eggshells which were prepared into hundreds of microns and furnace dried at 90oC continuously for eight hours to improve the bonding capability. They were then particulated into polyethylene matrix accordingly as per the designed weight ratios, 10%, 20%, 30% and 40%. From the result, it was learnt that the ES filler has improved mechanical properties of virgin PE as far as 5% to 9% depending on the filler weight ratio. Therefore, ES which was a burden for disposal and being environmental threat can now be used for the betterment of PE product performance.
Machinability Improvement by Workpiece Preheating during End Milling AISI H13 Hardened Steel
Authors: Suhaily Mokhtar , Nurul Amin A.K.M. , Patwari Anayet Ullah , Razak Nurhayati Ab.
Published: July 2011

Hardened materials like AISI H13 steel are generally regarded as s difficult to cut materials because of their hardness due to intense of carbon content, which however allows them to be used extensively in the hot working tools, dies and moulds. The challenges in machining steels at their hardened state led the way to many research works in amelioration its machinability. In this paper, preheating technique has been used to improve the machinability of H13 hardened steel for different cutting conditions. An experimental study has been performed to assess the effect of workpiece preheating using induction heating system to enhance the machinability of AISI H13. The preheated machining of AISI H13 for two different cutting conditions with TiAlN coated carbide tool is evaluated by examining tool wear, surface roughness and vibration. The advantages of preheated machining are demonstrated by a much extended tool life and stable cut as lower vibration/chatter amplitudes. The effects of preheating temperature were also investigated on the chip morphology during the end milling of AISI H13 tool steel, which resulted in reduction of chip serration frequency. The preheating temperature was maintained below the phase change temperature of AISI H13. The experimental results show that preheated machining led to appreciable increasing tool life compared to room temperature machining. Abrasive wear, attrition wear and diffusion wear are found to be a very prominent mechanism of tool wear. It has been also observed that preheated machining of the material lead to better surface roughness values as compared to room temperature machining.
Principal Methods of Experimental Design and Statistical Analysis Used in Experimental Studies of Machining Processes
Authors: Villeta M. , de Agustina B. , Sáenz de Pipaón J.M. , Rubio E.M.
Published: July 2011

In practice, there are a lot of factors that can affect the expected final outcome of machining processes. That is why during last decades a great number of experimental studies have been made for improving this kind of processes. As the realization of the tests for taking into account factors such as machines, materials, tools and cutting conditions requires resources of different types and can provoke environmental damage at different levels, diverse methods of experimental design and statistical analysis have been developed looking for efficient experimentation. This paper is focused on the study of these statistical methods. It collects the principal types of experimental designs and statistical procedures used in experimental studies for the control and the improvement of machining processes. Additionally, the review and analysis of the main works on the machining processes area for each one of these statistical tools has been made.
Current Research Trends on Dry, Near-Dry and Powder Mixed Electrical Discharge Machining
Authors: Khan Md. Ashikur Rahman , Rahman M.M. , Noor M.M. , Kadirgama K. , Maleque M.A.
Published: July 2011

Electrical discharge machining (EDM) technique has been widely used in modern metal working industry for producing complex cavities in dies and moulds, which are otherwise difficult to create by conventional machining. The process has the advantage of being able to machine hardened tool steels. However, its low machining efficiency and poor surface finish restricted its further applications. To address these problems, one relatively new technique used to improve the efficiency and surface finish is EDM in the presence of powder suspended in the dielectric fluid. Powder mixed electric discharge machining (PMEDM) is one of the recent innovations for the enhancement of capabilities of EDM process. In PMEDM, the electrically conductive powder is mixed in the dielectric fluid of EDM, which reduces the insulating strength of the dielectric fluid and increases the spark gap between the tool and workpiece. As a result, the process becomes more stable, thereby, improving the material removal rate (MRR) and surface finish. Moreover, the surface develops high resistance to corrosion and abrasion. This paper presents the current research trends on dry, near dry EDM and review on research carried out in the area of PMEDM.
Sensing Tool Breakage in Face Milling by Support Vector Machine
Authors: Hsueh Yao Wen , Yang Chan Yun
Published: July 2011

This paper introduces a new tool breakage diagnosis technique by using a support vector machine (SVM) in face milling. From the viewpoint of frequency domain, the paper is focused mainly on the diagnosis with spectrum of cutting force signals. With the spectrum, the SVM is learned to adapt the diagnosis. As the substantial benefits in classification, the system, joined the spectrum input and the SVM learning, is capable of responding in real-time to diagnose automatically when a tool fracture occurs even under the varying cutting conditions, and is really admissible to monitor the machining tool with or without breakage. As for the experimental results, they show that this new approach could sense tool breakage in a wide range of face milling operations.
Characterization and Photocatalytic Activity of N, Cd-Codoped TiO2
Authors: Gao Hong Tao , Liu Yuan Yuan , Zhao Xian
Published: July 2011

N, Cd-codoped TiO2 has been synthesized by sol-gel method coupling with thermolysis. The products were characterized by XRD, SEM, UV-visible DRS, XPS and BET analysis, respectively. The photocatalytic activities of samples were evaluated on the degradation of methyl orange (MO). It was showed that particle sizes of anatase photacatalysts were about 10-15 nm. The maximum specific surface area of the products was 102.7 m2⋅g-1. N atoms were incorporated into the TiO2 crystal lattice, while Cd atoms existed on the crystal surface. The optical absorption edge of N, Cd-codoped TiO2 was 435 nm, which illustrated that the product represented photoactivity in the visible region. It indicated a strong N-Cd synergistic interaction appeared to play a decisive role in driving the excellent photoactivity performance of N,Cd-codoped TiO2.
Investigation on the Rheological Behaviors of Styrene- Butaidene- Styrene Block Copolymer Solution
Authors: Wang Wan Jie , Guo Hao , Xu Xia , Cao Yan Xia , Wang Jing Wu
Published: July 2011

The viscoelastic behaviors of cyclohexane and dimethylbenzene SBS solutions with different concentrations have been investigated through dynamic rheological methods. The effects of solvent properties, concentration, stress and frequency on the rheological behaivors of SBS solutions have been carried out. The results show that the curves of dynamic shear stress tests show two modulus plateau, the dynamic moduli of dimethylbenzene SBS solutions are higher than those of the cyclohexane SBS solutions because dimethylbenzene is good solvent for SBS and the viscoelastic behaviors of solutions exhibit strong dependence on concentration.
Corrosion Mechanism of Atmosphere Spacein Oil Tank Containing Sulfur
Authors: Zhao Xue’e , Wei Xin Li , Liu Shi Fei
Published: July 2011

Oil tank is easily corroded by internal and external media in service. Corrosion types of gas spaces in oil tank were summarized, corrosion process was analyzed also. Through the research of corrosion mechanism of gas space of oil tank, author put forward that H2S corrosion was a dominant factor for gas space corrosion. H2S corrosion mechanism model at low temperature was obtained also. Metallic samples test showed that corrosion rate was decreased while the samples were placed in simulating atmosphere spaces of oil tank. Corrosion product iron sulfide has loose, porous, layered, and cracked structure. When ingredient of atmosphere varied with time，iron scale was produced, mixed with iron sulfide. Electrochemical test showed that the increase of acidity accelerated the cathode process and accelerated the corrosion rate of Q235-B steel.
Preparation of a Low Carbon Steel with Ultrafine Grained Microstructure through Rare Earth Micro-Alloying
Authors: Liu Cheng Jun , Liu Hong Liang , Jiang Mao Fa
Published: July 2011

The effects of the rare earth (RE) element on the microstructure of a hot-rolled low carbon steel (B450NbRE) were investigated under different heat treatment conditions. It was found that the B450NbRE steel with ultrafine grained structure could be successfully prepared with a certain content of RE additive under an appropriate heat treatment temperature between A1 (717°C) and A3 (880°C). The corresponding critical temperature increases with decreasing the RE content. For instance, the critical temperature is 800°C for the RE content of 0.0140 wt.%, but it increases to 850°C as the RE content decreases to 0.0075 wt.%
Bake Hardening Behavior of Cold-Rolled Dual Phase Steel Sheets
Authors: Jing Cai Nian , Chen Xiao Hui , Wang Ming Gang , Tan Qi Zhong
Published: July 2011

Effects of pre-straining, baking temperature and baking time on bake hardening (BH) behavior of cold-rolled dual phase steel were investigated. The results show that the investigated dual phase steel has clear BH behavior. Increased pre-straining led to the BH value decreased, while increased the baking temperature and prolonged baking holding time can all increase the BH value. The mechanics of bake hardening behavior in dual phase steel were discussed, and the effects of pre-staining on tensile strength after baking were also analyzed.
Deformation Behavior and Microstructure Characterization of AZ31 Processed by Equal Channel Angular Extrusion: Effect of Extrusion Temperature
Authors: Xu Shu Bo , Sun Ke Ke , Jing Cai Nian , Huo Yu Shuang , Wang Gui Qing
Published: July 2011

In this paper, influence of temperature on warm temperature equal channel angular of AZ31 alloy was investigated by using numerical simulation and experimental investigation. The effective stress distribution rules and load-stroke curves viartions were obtained at different temperature. And the distribution of effective strain and the rules of deformation uniformity of three temperatures extrusion processing for round workpiece are obtained. The proper temperatures extrusion processing is acquired through comparing the results of three extrusion routes. The effect of the temperature on the accelerated grain refining during the ECAE operation was discussed in the numerical calculations with a view to the use of the process to bulk AZ31 alloys. On the basis of the simulations, the warm ECAE experiments are carried out. The geometries of finally pressed workpieces of the different temperature pressed samples are in good agreement with finite element analysis results．
Temperature Dependent Photoluminescence of Fe-Doped TiO2 Nanowires Prepared by Hydrothermal Method
Authors: Rong G.Z. , Fan Duo Wang , Wang C.B. , Ling X.M. , Miao S.F. , Niu X.S.
Published: July 2011

The single-crystalline Fe-doped TiO2 nanowires have been successfully prepared by hydrothermal route. The nanowires have diameter about 50 nm and lengths of several micrometers. The morphological feature and structural characteristics of the samples are studied. Room temperature PL spectra properties and mechanism of Fe-doped TiO2 nanowires in different annealing temperature also are discussed.
Synthesis and Performance of Porous TiO2
Authors: Zhang Ying Chen , Wu Hong Yan , Zhu Min Cong , Wang En Qiang , Li Deng Xin
Published: July 2011

A composite photo-catalyst of nano-TiO2 (TIO) grafted in the pores of expanded graphite (EG) was prepared by a process that included microwave irradiation method and hydrolysis method directly. Fourier transformation infrared spectroscope (FT-IR), Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to characterize the structure and the chemical structure of the photo-catalyst. The results indicate that expanded graphite had a unique net-like pores structure and nano TiO2 was loaded on EG to form EG/ TiO2 (EGTIO) composite photo-catalyst.
Sulfation of Calcined Raw Meal in the Kiln Inlet Housing for the Cement Industry
Authors: Li Xiao Yan , Hu Zhi Juan , Ye Xu Chu , Yu Wei Min , Tao Cong Xi
Published: July 2011

The sulfation behavior of calcined raw meal was investigated in a laboratory fix-bed reactor under conditions typically for SO2 capture in the kiln inlet housing used in cement production. The initial period is characterized with a fast-increasing conversion, while the second period shows a slow-increasing conversion. A desirable temperature exists for sulfation of calcined raw meal. A smaller particle size favors the sulfation reaction. The initial conversion rate is significantly promoted by a higher SO2 concentration. The SEM examinations show that the sulfation process involves nucleation and growth of CaSO4 grains- the sulfation product. Increasing the temperature and extending the time result in fewer but larger CaSO4 grains in the product layer.
Study on Image Search Engine Based on Color Feature Algorithm
Authors: Huang Xian Ying , Chen Wei Wei
Published: July 2011

Considering the expansion, stability and the maneuverability of a search engine, a modular search engine based on the combination of keywords, image characteristics and content was designed. For the characteristics of image, a quantified method of color characteristics based on the maximum size of connected regions was raised. Experiments show that the method improves the retrieval efficiency and can get an expected search result more accurately, so as to satisfy the customer’s needs.
An Optimizing Design Approach for the Fiber Manufacturing Based on the Immune Genetic Algorithm-Optimized Neural Network
Authors: Zhu Hui Zhong , Ding Yong Sheng , Liang Xiao , Hao Kuang Rong , Wang Hua Ping
Published: July 2011

A novel neural network-based approach with immune genetic algorithm is proposed to conduct the optimizing design for the industrial filament manufacturing system. A new model is proposed in this paper to acquire better filament quality during such process. The proposed model was a combination of two components, namely, a traditional neural network which is used to simulate and an immune genetic algorithm-based part which is to improve the performance of the neural network component. Simulation results demonstrate that the proposed method can efficiently demonstrate the spinning process of filament and conduct the prediction of the filament quality with the production parameters as input data. Meanwhile, the proposed method enjoys faster speed and more precise accuracy, compared with traditional methods.
The Application of Requirement Engineering Model in Large Software Development Process
Authors: Tang Rong Fa , Huang Xiao Yu
Published: July 2011

Requirements engineering is the initial phase of software engineering process in which user requirements are collected, understood, and specified for developing quality software products. The requirement engineering process deserves a stronger attention in the industrial practices. In this paper, we proposed an effective requirement engineering process model for software development that can be used for software development processes to produce a quality product.