bluuebunny/crossref_metadata_2025 huggingface dataset:
Weldability and Toughness Evaluation of Ceramic Reinforced Steel Matrix Composites (TiB2-RSMC)
Authors: Bayraktar E. , Ayari F. , Katundi D. , Chevalier J.P. , Bonnet Frédéric
Published: July 2011

This paper reports the production and weldability and toughness evaluation of TiB2 (ceramic particles) reinforced steel matrix composites. These ceramic particles are optimal reinforcements for steel matrix composites because of their high thermal stability at higher temperatures, high modulus of elasticity, good weldability, low density and relative stability within a steel matrix. This new composite family has received much attention as potential structural materials due to their high specific strength and stiffness. Thus, there is significant interest in developing iron and steel matrix composites and evaluating their dynamic behaviors due to their potential for use in the automotive industry. The goal of the research described in this paper is to study the usage of this new steel family in the manufacture of light structures. Therefore, titanium diboride TiB2 reinforced steel matrix composites were characterized by optical and scanning electron microscopy. The dynamic behaviours of the base metal and welded specimens were tested under impact crash test conditions.
Mechanical Characterization Behavior of Boron Steel Sheet in Hot Press Forming Process with Cooling System
Authors: An S.H. , Kwon Ki Young , Kang Chung Gil
Published: July 2011

When cooling a boron sheet that has been heated to over 900 °C by hot press forming (HPF) process, the microstructure obtains a martensitic structure by controlling the cooling rate. HPF has advantages such as improvement in formability and material properties, and minimal springback of the formed material. The facts influenced by the cooling rate are determined by the heat transfer characteristics between the heated materials and the dies. In this study, controlling of the cooling rate is addressed by controlling the heat transfer coefficient of the material during the pressing process. This study demonstrates the material properties and microstructures of the formed material during the HPF process wherein cold dies are used to form the heated steel plate. This is achieved by varying the major forming conditions: the cooling rates, which is regarded as the most important process parameter.
The Effect of Incorporating Lithium Fluoride on the Compressive Strength and Diametric Tensile Strength of Glass Ionomer Cement
Authors: Mustafa Ammar A. , Al-Khateeb Khalid A. S. , Ismail Ahmad Faris
Published: July 2011

Experimental glass ionomer cement was prepared for the purpose of this study. Twenty disk specimens (16mm diameter x 10mm height) of test-GIC were prepared for the diametral tensile strength (DTS) test and twenty cylindrical specimens (6 mm diameter x 16mm height) were prepared for the compressive strength (CS) test. Specimens were stored in an artificial saliva at 37º C and (50±10%) of relative humidity in an incubator until testing. Five specimens of each GIC were submitted to CS and DTS test in each period, namely 1 hour, 24 hours, 7 days and 28 days. The specimens were tested in a Universal Testing Machine (Instron 1122, Instron corp., High Wycombe, U.K.) at a crosshead speed of 1.0mm/min for CS and 0.5mm/min for the DTS test until failure occurred. The results have revealed that incorporation of lithium fluoride in the formula of the test GIC might impart an increase in the mechanical properties of the GICs
Growth of Carbon Nanomaterials on Granular Activated Carbon
Authors: Onundi Yusuf Bamidele , Al-Mamun Abdullah , Al-Khatib Ma’an Fami R. , Ahmed Yehya M.
Published: July 2011

Since the discovery of carbon nanotubes (CNT) and subsequent Carbon Nanomaterials (CNMs), there has been an ever increased academic and industrial interest on there various fields of application due to their exceptional mechanical and electrical properties. In this work, granular activated carbon (GAC) made from palm Kernel shell (PKS) of mesh size 8x12 was impregnated with nickel as substrate catalyst for the growth of Carbon Nanomaterials (CNMs) in a chemical decomposition (CVD) reactor. Various percentages by weight of the nickel (1%, 3%, 5% and 7%) were impregnated on the GAC surface for CNM growth. The CNM growth took place at a fixed reaction temperature and gas flow rates for both the hydrogen gas and carbon source. Characterization of the novel composite material was carried out by using SEM, FESEM and TEM. The results show that growth was successful as at 1% nickel impregnation, while a denser network distribution and rougher surface of CNM was observed at 7% nickel. The growth of CNMs on a larger substrate GAC should make handling of the CNMs easier and it is expected to also open new doors of application in water treatment and oil refining.
Effects of Material Properties and Thickness of Die Attach on Warpage and Stresses of TSOP
Authors: Chang Chia Lung , Chen P.Y. , Huang M.H.
Published: July 2011

The assembly of plastic electronic package requires a sequence of process steps. Every process step induces thermal residual deformation and stresses on the assembled components, which cause mechanical effects on the subsequent process step. Processing model with considering the effect of chemical shrinkage on molding compound is built to simulate the package warpage and stresses in assembly. The processing model, a nonlinear model with element birth and death used to activate and deactivate the processing materials, can more realistically simulate a series of assembly processes in a plastic package. The stresses in package components are primary factor for the damage of package. The induced package stresses can cause the delamination between die/die attach interface or die attach/die pad interface. In this study, effects of material properties as well thickness of die attach on warpage and stresses of TSOP (Thin Small Outline Package) during assembly are discussed.
Development of Vibration Suppression Devices from Smart Fluids
Authors: Rashid Mohd. Mahbubur , Salami Momoh J.E. , Raisuddin K. M. , Mozasser R.
Published: July 2011

Semi-active control devices have received significant attention in recent years because they offer the adaptability of active control devices without requiring the associated large power sources. Magneto-rheological (MR) dampers are semi-active control devices that use MR fluids to produce controllable dampers. They potentially offer highly reliable operation and can be viewed as fail-safe in that they become passive dampers should the control hardware malfunction. To develop control algorithms that take maximum advantage of the unique features of the MR damper, models must be developed that can adequately characterize the damper’s intrinsic nonlinear behavior. Following a review of several idealized mechanical models for controllable fluid dampers, a model is proposed that can effectively portray the behavior of a typical magneto-rheological damper. Comparison with experimental results for a prototype damper indicates that the model is accurate over a wide range of operating conditions and is adequate for control design and analysis.
Electronic and Positron Properties of Zinc-Blende MgTe, CdTe and their Alloy Mg1-XCdXTe
Authors: Al-Douri Y.
Published: July 2011

Based on the pseudopotential scheme, the electronic and positron properties of zinc-blende compounds MgTe, CdTe and their alloy MgxCd1-xTe alloy have been studied. The agreement between our calculated electronic band parameters and the available experimental data is reasonable. For the ternary alloy MgxCd1-xTe, the virtual crystal approximation is coupled with the pseudopotential method. The energies at Γ, X and L points of MgxCd1-xTe alloy as a function of the alloy concentration are calculated. The electronic and positron band structures derived from pseudopotential calculations are also reported. Other quantity such as ionicity factor by means of our model with respect to the alloy concentration is discussed.
Developing of Honeycomb Shaped Cordierite Ceramic from Indigenous Raw Materials and its Characterization
Authors: Begum S. , Misran Halina , Aminuddin A.
Published: July 2011

Cordierite ceramic of chemical composition 2MgO-2Al2O3-5SiO2 has low value of thermal expansion, excellent thermal shock resistance, high porosity and high strength. The exhibited properties resulted wide range of industrial applications, especially in the catalytic converter, kiln furniture, diesel particulate filter and high frequency insulator. It occurs rarely in nature and its formulation from the indigenous raw materials is sensitive to the peak sintering temperature and holding time. Both the parameters are again affected on the source of raw materials. Hence optimization of peak temperature and holding time is crucial for each source of raw materials. In this paper three indigenous raw materials, clay, kaolin and talc were taken and mixed with different dopants. The prepared powder batch was sintered at different peak temperature and holding time. Among the three indigenous raw materials kaolin was found to be most suitable to formulate cordierite. The peak temperature was varied within the range of 1340°C -1400°C and the holding time was considered from 30 minutes to 90 minutes. Both the parameters had significant influence on the production of cordierite. The percent of cordierite formation was affected with both the variation of holding time and peak temperature. Tough thermal shock resistance was not influenced by any of the parameters, but the influence on the porosity was quite significant. The green body was also prepared from calcined powder batch and was sintered at different peak temperature. Calcination did not exhibit any affect on cordierite formulation.
Crack Arrest Model for Transversely Cracked Piezoceramic Strip under Mechanical and Electrical Yielding
Authors: Bhargava Rama R. , Kumar Satish
Published: July 2011

Crack arrest model is proposed for a poled piezoceramic strip under four different mechanical and electrical yield conditions. It is assumed that developed slide zone is bigger than that of developed saturation zone. Expressions are derived for energy release rate and load required to arrest developed zones. Results obtained are applied to predict the crack arrest of strip made of PZT-4, PZT-5H and BaTiO3. Results are presented graphically.
Thermal Investigation of Aluminium – 11.8% Silicon (LM6) Reinforced SiO2-Particles
Authors: Sayuti Mohd , Suraya S. , Sulaiman Shamsuddin , Vijayaram T.R. , Arifin Mohd Khairol A. , Baharudin B.T. Hang Tuah
Published: July 2011

High performance automotive, aerospace, electronics and other industrial and commercial applications are finding tremendous advantages in using metal matrix composites. The reinforcement is very important because it determines the mechanical properties, cost and performance of a given composite. An excellent in mechanical properties, combined with the ease of formability and low cost makes the application of metal matrix composite of aluminium-11.8% silicon reinforced SiO2 to increase steadily. This paper investigates the interrelationships between thermal properties and reinforcement content, microstructure and hardness of LM6 reinforced SiO2 composites. Specimens were fabricated by casting technique for 5, 10, 15 and 20% weight fractions of SiO2 particulate and mesh of: 65 micron. The experimental results show that the thermal diffusivity and thermal conductivity decreases as SiO2 wt.% of the composite increases and under hardness test, it was found that the hardness value had increased gradually with the increased addition of quartz particulate by weight fraction percentage.
Effect of Flame Retardant on Flame Retardancy and Mechanical Properties of Glass Fiber/Polypropylene Composites
Authors: Jeencham Rachasit , Suppakarn Nitinat , Jarukumjorn Kasama
Published: July 2011

Composites based on polypropylene and glass fiber were prepared by melt mixing. The effect of magnesium hydroxide as a flame retardant on flammability and thermal behavior of glass fiber/polypropylene composites was studied. Ratio of glass fiber to magnesium hydroxide in each composite sample was varied. Maleic anhydride grafted polypropylene (MAPP) was used to improve the interfacial adhesion between polypropylene and fillers. Flammability and thermal behavior of the composites were examined using a horizontal burning test and a thermogravimetric analyzer, respectively. Morphology and mechanical properties of the composites were also investigated. Magnesium hydroxide reduced the flammability while improved thermal decomposition temperature of the polypropylene composites. However, magnesium hydroxide showed a negative impact on the tensile strength of the polypropylene composites.
A Study on Delay Effect of Fatigue Life by Laser Welding Using Shot-Peening
Authors: Rong Hua Wei , Kim Hyung Jim , Park Won Jo
Published: July 2011

At present, welding technology is not only emphasized in the development of manufacturing technology but also application is expanding. In these systems, application of SUS as high-temperature material which is used for special purposes is attempted, and improvement of manufacturing technologies bear watching together with increase of using rate. Specifically, Wings with surface of three-dimensional shape usually applied to Fastener with purpose of lightweight. However, due to development of welding technology, methods of existing assembly tend to be replaced by welding, recently. Specifically, if laser welding techniques is applied, it minimizes heat-affected zone than other welding techniques. However, in the case of these special welding, residual stress is raised, and it fatally affects fatigue life. In order to remove residual stress and delay effect of fatigue life, shot-peening is executed; it executes shot-peening and verifies delayed effects of fatigue life. The intention of this study is to obtain the optimal conditions of shot-peening
Finite Element Analysis and Comparison of Castellated and Cellular Beam
Authors: Pachpor P.D. , Mittal N.D. , Gupta L.M. , Deshpande N.V.
Published: July 2011

The solid I section beam with creating hexagonal cavities (openings) has numerous advantages over conventional rolled sections. As they are light weight, strong, cheap and elegant. The opening in the web simplifies the work of the installer and the electrician, since taking pipes across beams presents no problems. A cellular beam (circular openings) is the modern version of the traditional castellated beam. The beam comprises pronouncedly asymmetric cellular tees, to provide a wide bearing for either pre-cast units or a profiled metal deck. The elastic finite element analysis of castellated beam and cellular beam is carried out to understand its behaviour under load. The failure pattern and stresses developed under same loading condition are studied. Based on the various modes of failure, the applicable methods of analysis are studied which includes plastic analysis, mid post yielding and buckling analysis. From the previous experimental results, one beam is selected and analyzed. Then the no of openings is varied as 2, 4 and 6 in selected beam. The shape of opening is considered as hexagonal and circular of same cross sectional area. The support conditions are considered as fixed, hinged and roller. Overall 18 cases are studied for same central point load and span with change of spacing of openings. The maximum Deflection and the maximum VonMises stress are worked out. The comparative study is carried out using software for finite element analysis ANSYS.
Effects of High Energy Radiation on Mechanical Properties of PP/EPDM Nanocomposite
Authors: Anuar Hazleen , Abd Razak S.B. , Kahar N. Md. , Jamal N.A.
Published: July 2011

Nanocomposites are the materials that are created by introducing nanoparticulates that always referred to as filler into the matrix. Blends of polypropylene (PP)/ethylene propylene diene monomer (EPDM)/Montmorillonite (MMT) were treated by compatibilizer MAPP and irradiation of electron beam. The effects on mechanical properties for both samples were compared with the untreated nanocomposites. Because each samples used different portion of clay loading, the effects of clay loading on mechanical properties is also observed. The sample is characterized by using Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD), tensile test and impact test.
Compatibilized PP/EPDM-Kenaf Fibre Composite Using Melt Blending Method
Authors: Anuar Hazleen , Hassan N.A. , Mohd Fauzey F.
Published: July 2011

Thermoplastic Elastomer (TPE) composite reinforced with Hibiscus cannabinus, L fiber (kenaf fiber, KF) was prepared via melt blending method using internal mixer at temperature 180°C, screw rotational speed at 40rpm for 10 min. TPE matrix is a blend of polypropylene (PP) and ethylene-propylene-diene monomer (EPDM) at a ratio of 70:30. The optimum fiber loading were investigated from 0% to 20% by volume. The effect of coupling agent maleic anhydride polypropylene (MAPP) on the TPE composite has been investigated. The result shown that, with increasing the kenaf fiber content gradually increased the tensile strength and flexural strength for both treated and untreated PP/EPDM-KF composite. However, at 20% of kenaf fiber loading, it showed decreasing in impact strength due to brittleness of the samples. From the scanning electron micrograph (SEM) it has shown that the composite, with compatibilizer promotes better interaction between TPE and kenaf fiber.
Fabrication of CuSiC Composite by Powder Metallurgy Route
Authors: Azreen A.R. Fatimah , Sutjipto Agus Geter E. , Adesta Erry Yulian Triblas
Published: July 2011

Copper-based composite now is a potential material for various applications, while powder metallurgy processing technique is an alternative for high temperature processing materials and net shape component. In this research, Cu-based composite containing 10-50 vol% SiC fibers was fabricated by employing the powder metallurgy route. The mixtures of SiC fibers and Cu particles were blended in a ball milling machine with the addition of ethanol at 150rpm. Then, the mixtures were uniaxially compacted into a ɸ13.5mm cylindrical pallet and followed by sintering in vacuum furnace from 800-950°C for 4 hours. The density of the composite decrease with increasing SiCf and density as high as 87% for 10vol% SiCf/Cu matrix sintered at 800°C had been achieved. The Vickers hardness of 774MPa also had been achieved for 10vol% SiCf/Cu matrix but sintered at 900°C.
Mould Filling and Pressure Distribution for Polymer Resins
Authors: Mohd A. , Hindle C. , Yusoff W.A.Y.
Published: July 2011

The application of simulation software packages for mould design and injection moulding process is becoming importance to optimizing the moulding quality and satisfy market needs. This paper presents the simulation of mould filling and packing for various polymer resin types. The filling and packing pressure phases for different type of polymer resins as well as the flow behaviour of molten resin in the mould cavity were investigated. Three common polymer resins which are amorphous and crystalline thermoplastics were used. Cylinder component cups with variation of wall thicknesses were designed. Two-cavity prototype moulds for cylindrical shape component were constructed by using AutoCAD 2006 including assembly and part drawings. The 3D model was produced by using Autodesk Inventor Professional. The result successfully revealed that polyamide resin required shorter time for filling the cavity and less pressure compared to PS and ABS.
Material Properties and Design Aspects of Folding Bicycle Frame
Authors: Maleque M.A. , Hossain M.S. , Dyuti S.
Published: July 2011

successful design of folding bicycle should take into account the function, material properties, and fabrication process. There are some other factors that should be considered in anticipating the behavior of materials for folding bicycle. In order to understand the relationship between material properties and design of a folding bicycle and also for the future direction in new materials with new design, a comprehensive study on the design under different conditions are essential. Therefore, a systematic study on the relationship between material properties and design for folding bicycle has been performed. The advantages and disadvantages matrix between conventional bicycle and folding bicycle is presented for better understanding of the materials properties and design. It was found that the materials properties of the folding bicycle frame such as fatigue and tensile strength are the important properties for the better performance of the frame. The relationship between materials properties and design is not straight forward because the behavior of the material in the finished product could be different from that of the raw material. The swing hinge technique could be a better technique in the design for the folding bicycle frame.
Development of a Novel Rapid Manufacturing Process for Micro-Cylindrical Lens Array
Authors: Huang Chien Yao , Huang Kuo Cheng , Chen Jun Cheng , Chang Keng Souo , Tseng Shih Feng , Chou Chang Pin
Published: July 2011

This paper proposed a novel method to fabricate micro-cylindrical lens array (μ-CLA) by using wire electrical discharge machining (WEDM) and precision glass molding (PGM) technique. Micro slits fabricated on the surface of tungsten carbide mold material with outline dimensions from 0.3mm to 2.1mm, the width and depth of 1 mm. The PGM processing parameters including width of slits, molding temperature, molding force and stroke were discussed. Moreover, the characteristics of μ-CLA were measured by contact profilometer. In addition, the relationship between the dimensions of the slit on tungsten carbide mold and the characteristics of μ-CLA also discussed.
Reduction of Sintering Temperature of Porous Tungsten Skeleton Used for Production of W-Cu Composites by Ultra High Compaction Pressure of Tungsten Powder
Authors: Ghaderi Hamidi A. , Arabi H. , Rastegari Saeed
Published: July 2011

Production of tungsten-copper composites includes compaction and sintering of tungsten powder, then infiltration of copper melt within the tungsten skeleton. Sintering of tungsten compacts usually requires a temperature range of 1800 to 2200°C. This means, this process not only needs advanced heating equipments and high expenses but also may cause formation of defects such as structural heterogeneities, cracks and distortions. In this research the required sintering temperature was reduced to 1500°C by increasing compaction pressure. Also the relation between compaction pressure applied through a cold isostatic press (CIP), and green density of the compacted tungsten powder was established. In addition, the effect of various pressures on densification of tungsten compacts during sintering at moderate temperature, i.e. 1500°C was studied, and the optimum structure for infiltration was chosen. Then by infiltrating Cu melt into the optimized W-skeleton, composites of W-Cu having a density of 17.2 gr/cm3 were produced. This method of production provides an innovative technique for obtaining a desired density of infiltrable skeleton, sinterable at a lower temperature than the temperatures used for the conventionally packed W-compacts without introducing structural inhomogeneities during sintering. Study of some characteristics of the optimized composite produced by the above technique satisfied the requirements for production of W-Cu composites having all the specifications given for these types of composites produced at higher temperatures than 1500°C.
Failure Prediction in Drawing Processes of Mg Alloy Sheet by the FEM and Ductile Fracture Criterion
Authors: Kim Sang Woo , Lee Young Seon , Kang Beom Soo
Published: July 2011

In this work, in order to predict the forming failure of AZ31 magnesium alloy sheet in drawing process at elevated temperatures, a series of square cup tests at various temperatures and FE analyses were carried out. The critical damage values and the mechanical properties dependent on strain rates and temperatures were evaluated from uniaxial tensile tests and those were utilized to the forming failure prediction using FE analysis. Based on the plastic deformation history obtained from FE analysis and Cockcroft and Latham’s ductile fracture criterion, the fracture initiation time and location were predicted and verified with the experimental results.
Influence of Cutting Parameters on Machinable Glass Ceramic Processed by End Milling
Authors: Reddy Moola Mohan , Abou-El-Hossein Khaled A. , Gorin Alexander
Published: July 2011

This experimental research work attempted to use End milling on Machinable Glass Ceramic (MGC) using micro grain solid carbide end mill under dry conditions. The predictive Surface Roughness model has been developed in terms of Spindle speed, Feed rate and axial depth of cut by Response Surface Methodology (RSM). The influence of each milling parameter analyzed and results showed that axial depth of cut was the most dominant variable. The adequacy of the model has been verified by ANOVA.
Effects of Synthesis Parameters on the Preparation of Carbon Nanofibers by Ethanol Catalytic Combustion
Authors: Cheng Jin , Zou Xiao Ping
Published: July 2011

In this paper, the effects of position of substrates in flames, preparation time and stability of flames on carbon nanofibers are investigated in ethanol catalytic combustion. For the position of substrates, our results indicate that the temperature at the lower height (h<1cm) is too low (less that 500°C) to grow carbon nanofibers; the temperature at higher height (h>2.5cm) is suitable for the growth of carbon nanofibers, but the carbon source is insufficient because of sufficient combustion of ethanol; the optimal position of substrates in flames is more than 1cm and less than 2.5cm for massive yield because the temperature of flames is suitable for the growth of carbon nanofibers and the carbon source is also sufficient. For the preparation time, our results indicate that the optimal preparation time is more than 5min and less than 30min for massive yield. If the preparation time is excessive long (more that 30min), the deposits partly become burning in flames due to excessive products on substrates. The stability of flames has effects on the morphology and graphitization of products. Our experimental results indicate that stable flames prefer to produce noncoiled carbon nanofibers with relatively good uniformity and higher graphitization because the relatively stable flames could provide a relative stable synthesis environment.
Small Hole EDM by Current Dividing Based on Discharging Area
Authors: Wang Xu Yue , Li J.L. , Liang Yan De , Xu Wen Ji , Wang L.J.
Published: July 2011

A new EDM method of small hole is presented in which critical size of EDM drilling can be reduced less than that of limit of primitive EDM system by current dividing. The drilling characters of small hole EDM by means of current dividing based on a principle of discharging-area equalization were studied and discussed. The experimental results show that drilling speed and discharging gap decrease a little, and electrodes wear increases slightly. There is a drilling consistency in EDM ability between single and double electrodes under discharging-area equalization, and new method helps to improve the drilling precision. The research outcomes provide a deeper understanding for a small hole EDM.
Pattern Recognition Method to Predict Recycling Strategy for Electronic Equipments
Authors: Noor M.M. , Kadirgama K. , Rahman M.M. , Maleque M.A.
Published: July 2011

The environmental problem is an extensive, complex problem, and some example areas of study are energy consumption, material/resources use, recycling, and environmentally relevant substance control. Life cycle engineering is the engineering and design of products and processes to minimize the cost and environmental impact for the life cycle phases of a product. Functional Radial Basis Function Networks (FRBFN) is used to determine recycling strategy (reuse, service, remanufacture, recycle with disassembly, recycle without disassembly and disposal). Seven parameters (wear – out life, technology cycle, level of integration, number of parts, reason for redesign and design cycle) were considered as the input for the FRBFN model. Eight equipments were selected to be examined such as vacuum cleaner, washing machine and television. All the results verify previous literature study. The prediction model predicts the end life strategies quite closely with best industry practices but only 25 % match average industry practices.
Optimization of Process Parameters on EDM Milling of Stainless Steel AISI 304
Authors: Asif Iqbal A.K.M. , Khan Ahsan Ali
Published: July 2011

Electrical Discharge Machining (EDM) is one of the most widely used non conventional machining processes for removing material from workpiece by means of a series of repeated electric discharges. This process is now one of the main techniques used in die production and has good accuracy and precision with no direct physical contact between the electrodes so that no mechanical stress is exerted on the workpiece. Electrical discharge milling (ED-milling) is an emerging technology where a cylindrical tool electrode follows a programmed path in order to obtain the desired shape of a part. The current investigation aims to optimize the process parameters during EDM milling of stainless steel by using copper electrode. The selected input parameters used for the study are voltage, rotational speed of the electrode and feed rate while the responses are material removal rate (MRR), electrode wear ratio (EWR) and surface roughness (Ra). Response surface methodology is used in the study. The experimental design is formed by using design expert software. Central Composite design (CCD) is used to identify the optimum operating condition in order to obtain maximum MRR, minimum EWR and minimum Ra as response. The result shows that the machining parameter setting of voltage 120 V, rotational speed of electrode 1200 rpm and feed rate 4μm/s, gives optimized responses MRR 5.0259 x 10-3 mm3/min, EWR 53% and Ra 0.79 μm.
Fabrication of Hierarchical SnO2 Nanocrystals and their Sensing Properties to Volatile Organic Compound Vapors
Authors: Chen De Liang , Li Tao , Yin Li , Zhang Rui , Li Xin Jian
Published: July 2011

Hierarchical SnO2 (H-SnO2) and particulate SnO2 (P-SnO2) nanostructures were synthesized by a hydrothermal method with and without the aid of sodium 1-dodecanesulfonate (SDS), respectively. X-ray diffraction and scanning electron microscopy were used to characterize the products obtained. The sensing properties of the H-SnO2 and P-SnO2 nanostructures to volatile organic compound gas (VOCs) were measured. The H-SnO2 sensors show better gas-sensing performance than the P-SnO2 sensors due to the hierarchical microstructure.
Study on Non-Isothermal Crystallization Kinetic of Tundish Covering Fluxes
Authors: Sun Li Feng , Wang Hong Po , Liu Chun Lai , Zou Yong , Jiang Mao Fa
Published: July 2011

Basic tundish covering flux is widely used in continuous casting production of high quality steel because of good heat insulation function and the properties of absorbing inclusions. However, there is a serious problem of incrustation caused by basic tundish covering flux in process of pouring and it could be dramatically influenced by the crystallization behaviors of covering flux. In the paper, the crystallization time and ratio of basic tundish covering fluxes were investigated by high temperature electrical resistance furnace and single hot thermocouple apparatus. Based on the crystallization kinetic knowledge and experimental results, Avrami equation was modified, the non-isothermal crystallization equation that could quantitatively describe the crystallization behaviors of basic tundish covering fluxes was established.
POSS-NH2/Cyanate Ester Resin Organic-Inorganic Hybrids: Curing Reaction and Dielectric Properties
Authors: Zhang Zeng Ping , Chen Shuan Fa , Pei Jian Zhong
Published: July 2011

A functional POSS monomer (POSS-NH2) was employed to modify cyanate ester (CE) resin. A series of POSS-NH2/CE hybrids containing different content of POSS have been prepared by melt casting and then curing. The curing kinetics and reaction mechanisms of the resin systems were studied by using FT-IR. Dielectric properties of the hybrids were also investigated. FT-IR results show that both temperature and POSS content may influence the curing reaction of CE. POSS-NH2 mainly displays the catalytic effect at higher temperature (220oC). The circumstance is more complex at lower temperature(190oC). CE1 containing 1 wt% of POSS has the best dielectric properties.
Morphology and Tribological Behaviors of In Situ Polymerized Nano-SiO2/Polyacrylate Nanocomposites
Authors: Hu Xiao Lan , Li Yan Jie , Dong Yan Ming
Published: July 2011

An interfacial polymerization method for polyacrylate resin was adapted to fabricate nanocomposites with nano-SiO2 particles via in situ polymerization. The tribological behaviors of the nano-SiO2 nanocomposites are briefly discussed in terms of types of functionalization and nanoparticle loading. Nano-SiO2 functionalization with three silanes improved the nanoparticles interfacial interaction and compatibility in the nanocomposites, resulted in lower friction coefficient and wear mass. And the results of DSC also testified that. The wear mass and friction coefficient of the nanocomposite containing 3 wt% nanoparticles with KH570 silane are 50.8mg and 0.20, respectively. Results of RCA show that the incorporation of the nano-SiO2 into the polyacrylate resin improves the scratch resistance significantly. Results of SEM indicate that the neat polyacrylate resin is dominated by adhesive wear, going with tearing resin, while all nanocomposites containing 3 wt% nanoparticles with silane are dominated by particle adhesive, going with soft adhesive wear.
Shape-Memory Behavior of Poly(L-Lactide)/Poly(ε-Caprolactone) Blends
Authors: Dong Hai Qing , Liu Li Jian , Li Yong Yong
Published: July 2011

Poly(L-lactide) and poly(ε-caprolactone) (PLLA/PCL) blends with various weight ratios were compounded by melt mixing and their shape memory properties were investigated. The thermal properties, surface morphology and dynamic mechanical properties of the blends were characterized. The results demonstrate that the introduction of PCL improves the process of crystallization of PLLA whereas the reverse situation is for PCL. PLLA/PCL blends were found to exhibit an immiscible behavior from the characterizations of surface morphology. DMA tests show the blends with different weight ratios have different transition temperatures. The properties of blends provide the basis of owning shape memory behavior. The strain recovery ratio (Rr) of PLLA/PCL blend with the weight ratio of 1:3 was about 95% within 22s, whereas the Rr of other blends were less than 75% within 23~30s. It was found that lower transition temperature combined with increased crystallization of PLLA with the increasing PCL content contribute to such a good shape memory effect.
Laboratory Study of Pavement Performance of Basalt Fiber-Modified Asphalt Mixture
Authors: Zheng Yuan Xun , Cai Ying Chun , Zhang Ya Min
Published: July 2011

In order to discuss the effect of the basalt fiber on reinforcing pavement performance of asphalt mixtures, the optimum dosage of asphalt and fibers were studied by the method of Marshall test and rut test firstly. Then pavement performances of basalt fiber-modified asphalt mixtures were investigated through tests of high temperature stability, water stability and low temperature crack resistance, and compared with that of polyester fiber, xylogen fiber and control mixture. The testing results showed that the pavement performance of fiber-modified asphalt mixture are improved and optimized comparing with control asphalt mixture, and the performance of basalt fiber-modified asphalt mixture with best composition were excelled than those of polyester fiber and xylogen fiber.
Effects of SiO2 and In Situ Crosslinking on the Swelling and Thermal Properties of Poly(vinyl Alcohol)/SiO2 Hybrid Films
Authors: Liu Jie , Tang Ke Yong
Published: July 2011

Poly(vinyl alcohol) (PVA)/SiO2 hybrid films were prepared through hydrolysis of tetraethoxysilane (TEOS) in the presence of PVA solution, followed by the in-situ crosslinking with formaldehyde (HCHO) in acidic circumstance. The swelling and thermal gravimetric (TG) analysis was employed to evaluate the influence of SiO2 and crosslinking on the properties of the hybrid films. The results indicate that SiO2 affects effectively the swelling property and thermal stability of the hybrid films because of both the filling and crosslinking effects of SiO2. With increasing the crosslinking time, the swelling ratio at equilibrium of the hybrid films decreases. The swelling ratio at equilibrium of the hybrid films is sensitive to the SiO2 content, which is similar to the swelling ratio at equilibrium (65~75%) for PVA and PVA/SiO2 hybrid films with enough crosslinking time (12h). Compared to the film without in-situ crosslinking, the crosslinked PVA/SiO2 film showed a lower swelling ratio at equilibrium and an increased diffusion coefficient at the initial stage of swelling.
Rapid Synthesis of Cyclomatrix Polyphosphazene Spheres and their Application for the Production of Microporous Carbon Spheres
Authors: Fu Jian Wei , Xu Qun
Published: July 2011

Uniform cyclomatrix polyphosphazene spheres with diameter of about 410 nm were firstly synthesized rapidly at room temperature by precipitation polymerization of hexachlorocyclotriphosphazene with 4,4′-sulfonyldiphenol, using triethylamine as acid-acceptor and acetonitrile as solvent. Then, monodisperse carbon spheres with abundant micropores were produced by carbonization of the polyphosphazene spheres at a high temperature under a nitrogen atmosphere. As-produced carbon spheres were well characterized by SEM, TEM, EDX, and N2 adsorption technique. Results show that the carbon spheres possess an average diameter of 320 nm, a BET surface area of about 752 m2·g-1, a total pore volume of 0.55 m3·g-1, and a micropore size distribution.
Piezoresistive Effect of Multi-Wall Carbon Nanotube Reinforced Epoxy Resin Coating
Authors: Luo Jian Lin , Li Qiu Yi , Zhao Tie Jun , Sun Sheng Wei
Published: July 2011

Some conductive MWNT with different loading was filled in epoxy resin through the dispersion technique of surfactant-decoration, high-intensive shear mixing, and bath sonication process. This kind of conductive functional resin coating was then simply brushed on a FRP sheet surface. The electrical conductivity of the cured nanocomposite coating was acquired by four-electrode method to explore the percolation threshold and piezoresistive effect. The change in its longitudinal strain of the coating and FRP sheet was simultaneously sampled under three-point bending. Results reveal that, at the onset percolation threshold (2.0%), the nanocomposite possesses superior piezoresistive effect with high strain-sensitivity (up to 27), which favors to health monitoring to FRP structure used as a novel self-sensing coating.
Solid Phase Synthesis of Novel Fullerene Nucleotides Conjugates
Authors: Zhang Jing , Zhang Ya Dong
Published: July 2011

N-substituted 3, 4-fullero pyrrolidine was synthesized according to 1, 3-dipolar cycloaddition of the azomethine ylide. Aspartic acid with protected α-amino and α-carboxyl groups was reacted with the activated hydroxyl group of N-substituted 3, 4-fullero pyrrolidine. The products were deprotected, affording the monofullerene aspartic acid (mFas). The conjugate FasT was synthesized by reaction of mFas containing protected amino group with the thymidylic acid derivatived controlled pore glass (CPG) using solid phase synthesis. All of the above fullerene derivatives were characterized by UV–vis, 1H NMR, IR and MS spectrometric analysis, giving the correct spectra with regard to their chemical structure. The chemical structures of fullerene nucleotides conjugate FasT is different from previous reports and may have novel biological properties. Moreover, they are more suitable for applications in biomedical research due to their solubilization in THF and DMSO. They have a potential to be used as monomer for the automatic synthesis. It allows further conjugation with specific biomolecules including amino acids, peptides, nucleotides and nucleic acids. A novel method has been developed to synthesize fullerene nucleotides conjugate. Their unique chemical structures make them very interesting for their potential use in medicine and biology.
Determination of Gold Surface Mechanical Behavior in Electro-Thermo-Mechanical Coupled Service Using Atomic Force Microscopy
Authors: Wang Quan , Hu Ran , Zhang Jin , Yang Ping
Published: July 2011

In this paper, gold (Au) surface mechanical behaviors in electro-thermo-mechanical coupled service are studied using atomic force microscopy. The experimental results indicate that some pile-ups of the metal, caused by indentation, are formed whether or not an external electric field is applied during indentation. Scanned topographical images reveal a bright area around the indentation hole, indicating the area where the material had been pushed out. It was determined that when a DC external field is applied to a sample, the hardness value of the tested sample presents an increase trend with the increment of electric current, but a decrease trend for the residue area and the elastic modulus.
Study on the Electrochemical Performance of Carbon-Coated LiFePO4 Prepared by Sol-Gel Method
Authors: Yang Rong , Kang Er Wei , Jiang Bai Ling , Song Xiao Ping
Published: July 2011

LiFePO4/C is synthesized via sol-gel method using Fe3+ as iron sources and complexing agents, followed by sintering at high temperature for crystallization. The amount of carbon in these composites is less than 6.8 wt.% and the XRD experiment confirms that all samples are pure single phase indexed with orthorhombic Pnma space group. The particle size of the LiFePO4/C synthesized by acetic acid as complexing agent is drastically fine with 200nm. The electrochemical performance of this material, including reversible capacity, cycle number and charge-discharge characteristics, exhibits better.
Surface/Interface Synergetic Effect-Induced Great Optical Spectral Change with Ag Content for Ag Nanoparticles Dispersed in Mesoporous SiO2
Authors: Liu Pei Sheng , Hu Jin Lian , Cai Wei Ping , Lu Yun
Published: July 2011

The evolution of optical absorption and photoluminescence (PL) spectra with different Ag content (from 0.14 wt % to 2.80 wt %) has been investigated for Ag/mesoporous SiO2 when heating in H2 and air. It has been found that, in accordance with alternating heat treatment of the sample with fairly low Ag content in H2 and air, the surface plasmon resonance (SPR) absorption of Ag nanoparticles alternately and reversibly appears and disappears, whereas its PL emission alternately disappears and appears. However, such reversible change can not happen in the sample with high Ag content. With gradual increase of Ag content, the two kinds of spectra take great and regular change. The results have firstly been discussed based on two contrary mechanisms coexisting in air at high temperature (i.e., oxidation reaction and thermal reduction reaction). In particular, the abnormal oxidation and the great optical change with Ag content is closely relative to surface/interface synergetic effect between Ag, O2 and SiO2 matrix despite SiO2 usually being regarded as a chemical inert medium to noble metals. The study would provide valuable reference for optical switch, gas sensor, nano optical modulation of SiO2-based optical devices, and give valuable information for surface/interface chemistry and catalysis in Ag nanoparticles and SiO2 assemble system.
Investigation on Ti-Deoxidized Products Inducing Formation of Intragranular Ferrite
Authors: Qi Jiang Hua , Wu Jie , Suo Jin Ping , Xue Zheng Liang
Published: July 2011

Steel samples were prepared using a vacuum carbon deoxidization process combined with a final Ti-deoxidation process. Ti-deoxidized products inducing formation of intragranular ferrite (IGF) was investigated by using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) through various specimens by different methods, as follows: metallographic specimens, electrolyzation, ion thinning technology, RTO method and so on. Mn is found to be more extensively distributed than S in the core of inclusion, which shows that Ti2O3 has character of absorbing Mn. The Mn-depleted zone (MDZ) exists in the peripheral steel of inclusion, the more near the inclusion, the more obvious depletion of Mn. It is also found that outer layer of inclusion exists S-rich and Mn depletion area in specimens prepared using RTO method under TEM. Mn- depleted zone in steel and Mn-depleted but S-rich layer in the periphery of the inclusion indicate that Mn diffuses and diverts is step by step in steel and inclusion, and the extent of S-rich and Mn depletion area should be related with degree of Mn absorbed by Ti2O3 and original precipitation amount of MnS.
Crystallographic and Electrochemical Characteristics of Melt-Spun Ti45Zr30Ni25RE3 (Y, La) Alloys
Authors: Liu Bao Zhong , Fan Yan Ping , Zhang Bao Qing
Published: July 2011

Ti45Zr30Ni25RE3 (Y, La) alloys were prepared by melt-spun at wheel velocities of 20 m s–1. Ti45Zr30Ni25 and Ti45Zr30Ni25La3 were composed of I-phase, amorphous and Laves phases. Ti45Zr30Ni25Y3 consisted of amorphous phase and I-phase. The addition of La and Y caused the decrease of maximum discharge capacity and the increase of cycling stability, which should be ascribed to the change of various phase abundant. The high-rate dischargeability of Ti45Zr30Ni25 alloy electrode was better than that of Ti45Zr30Ni25Y3 and Ti45Zr30Ni25La3 alloy electrode, which was attributed to the better electrochemical kinetics.
Effects of pH and Dispersant Concentration on Properties of Li1.075Nb0.625Ti0.45O3 Aqueous Suspension
Authors: Li Shao Chun , Geng Yong Juan , Zhang Qi Long , Yang Hui
Published: July 2011

The dispersion behavior of the solid solution Li1.075Nb0.625Ti0.45O3 (LNT) in aqueous media was studied. Optimum dispersing conditions were investigated in terms of zeta potential, sedimentation, and rheology measurements. Zeta potential measurement showed that the isoelectric point (IEP) of the LNT particles was shifted from pH 3.7 to pH 2.6 after adsorption of PAA-NH4 and made the LNT surface more electronegative. Good agreement between zeta potential, sedimentation, and rheological test was found, which identified an optimum pH value of 10 and an optimum dispersant concentration of about 0.6 wt%. The green microstructures of the casting tapes bear a direct relationship to the state of dispersion of the slurries. The results showed that PAA-NH4 is a suitable dispersant for obtaining well-dispersed LNT slurries.
Effect of Plastic Deformation on Microstructure Evolution of a High Strength X100 Pipeline
Authors: Qi Li Hua , Niu Jing , Yang Long , Feng Yao Rong , Zhang Jian Xun
Published: July 2011

The effects of plastic deformation on the microstructure evolution of grade X100 pipeline were investigated by SEM, TEM and EBSD test. The result shows that quasi-polygon ferrite deforms firstly in the initial stage of plastic strain, and then both acicular ferrite and granular bainite change remarkably with the plastic strain value increase. When the tension stress reaches the tensile strength, micro-cracks nucleate around the inclusion and M/A constitute, expand with the plastic deformation increases, finally cracks connection causes the crack penetration until the expiration. Furthermore, the microscopic orientation concentrates in {111} <112> and {112} <110> direction before the deformation, while crystal orientation in {111} direction enhanced after the deformation.