bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiments on Olive Husk-Addition to Masonry Clay Bricks on their Mechanical Properties, and their Application and Manufacturability as an Insulating Material
Authors: Alami Abdul Hai
Published: December 2009

Clay has been used in Jordan as a building material for decades. This paper investigates the effects of adding olive husk –another locally available solid waste material- on the mechanical properties of the clay composite, and its modification of the ductility and thermal resistance for use as an insulating material.
Laminated Metal Tooling (LMT) process will be used to manufacture the dies required to cast and dry the test specimens. A discussion will also be included regarding the eligibility of the material for the use as a low-cost, high efficiency insulating material depending on the manufacturability of husk-enhanced clay sheets.
Joining of Polycarbonate Ring/Disk to Metal Sheet/Shaft and its Easy Disassembly
Authors: Kasuga Yukio , Okai T. , Kawamori Shigehiro
Published: December 2009

For the possibility of easy disassembly of a joint assisted by strain recovery, the joint is fabricated with a cold rolled circular polycarbonate (PC) disk embedded in the center of an aluminium or a PC disk. Also, a shaft and a hollow circular disk are assembled by compressing or press fitting a cold rolled PC ring into the gap between them. First, the cold rolled polycarbonate disk is heat treated and the change in geometry is examined. Secondly, in order to evaluate joint strength, shear force and torque of the assembled joints are discussed with regard to reduction in thickness, tool clearance and interference. Lastly, joints are heat treated and the disassembly is checked. The cold rolled disk is recovered with the temperature 190°C for 20min. In embedding, disk compression in addition to rolling reduction is effective in increasing joint strength. In fabricating the shaft/disk joint, deformation of polycarbonate was not effective due to the recovery in room temperature after joining, while press fitting of the polycarbonate ring could fabricate the assembly. Heat treatment helped the joint to be automatically disassembled. The directly joined parts became completely apart, but the shaft/disk joint was disassembled only between the ring and the disk.
Structure Features of Martensite and Residual Austenite during Treatment with Concentrated Energy Fluxes
Authors: Stavrev Dimitar , Dikova Tsanka D.
Published: December 2009

The paper deals with the structure features of Fe-C alloys quenched by means of laser, electron beam and plasma arc. The martensite and residual austenite obtained are highly inhomogeneous. Their morphology and distribution depend both on the initial state before quenching and on the kinetics of the temperature changes. Four different structures of martensite are observed – package, lamellar isothermal, lamellar thermo-kinetic and “feathery nest-like”. The new martensite structure observed, called by us “feathery nest-like”, is a result of explosive austenite-martensite transformation in pearlitic irons. It differs from the classic modification in its specific morphology. Low-carbon package martensite occupies the regions of the former ferrite grains. Its hardness reaches 1050-1150 HV0.1. In the regions of microstructure with increased carbon concentration lamellar martensite is observed. The residual austenite is with different proportion in relation to the martensite. In particular regions its quantity could reach 100%. It is characterized by a high quantity of imperfections and high mechanical properties. Its hardness reaches 450-500 HV0.1. The higher the power density and the lower the energy density of the concentrated energy flux, the higher the residual austenite quantity.
Structure and Properties of High-Chromium-Alloyed Upper-Eutectoid Steels after Hardening with Concentrated Energy Fluxes
Authors: Stavrev Dimitar , Dikova Tsanka D.
Published: December 2009

The present paper deals with the structure and properties of two types of tool steels with high chromium content (12% Cr) hardened by means of Concentrated Energy Fluxes (CEF). The treatment conditions are chosen to ensure liquid state transformations. The melted zone of the surface layer features a quasi-ledeburite structure, consisting of inhomogeneous residual austenite and Cr-containing carbides of MmCn type. This austenite is strongly cold hardened and over-saturated with Cr and carbon. The micro-hardness of this region varies from 400 up to 800 HV0.1. The higher the energy density, the lower the hardness and the wider the modified layers. The lower hardness is due to the presence of nearly 100% austenite. Higher hardness was obtained in the heat affected zone. Carbides of M23C6, M7C3, M6C, M3C and МС types were identified. A scheme of carbide changes after treatment with CEF is given.
An Overview of Microfluidic Mixing Application
Authors: Naher Sumsun , Orpen Dylan , Brabazon Dermot , Morshed Muhammad M.
Published: December 2009

Microfluidics is a technology where application span the biomedical field and beyond. Single cell analysis, tissue engineering, capillary electrophoresis, cancer detection, and immunoassays are just some of the applications within the medical field where microfluidics have excelled. The development of microfluidic technology has lead to novel research into fuel cells, ink jet printing, microreactors and electronic component cooling areas as diverse as food, pharmaceutics, cosmetics, medicine and biotechnology have benefited from these developments. Since laminar flow is prevailing at most flow regimes in the micro-scale, thorough mixing is a challenge within microfluidics. Therefore, understanding the flow fields on the micro-scale is key to the development of methods for successfully microfluidic mixing applications.
Incremental Forming of Multislope Shaped Components
Authors: Ambrogio Giuseppina , Cossari A. , Filice Luigino , Manco G. Leonardo
Published: December 2009

In the last years, a number of studies on Incremental Sheet Forming have been focused on formability analysis and, in particular, on the development of models able to predict material response also in the design phase. Due to mechanics complexity, up to now process application is directly dependent on a preliminary experimental investigations based on the execution of trials and errors tests; a set of experiments, in fact, is necessary to determine the industrial feasibility. Of course this approach is very expensive and time consuming and, for this reason, new techniques to perform reliable guidelines for the designer are strongly requested.
In the paper an effective statistical methodology has been applied with the aim to build a suitable base of knowledge minimising the number of experimental tests for identifying an optimal set of parameters which strongly impact on the process performance.
Effect of Milling Time on Crystallite Size and Morphology of Nickel Aluminde Based Composite Powder Prepared by Mechanical Assisted SHS Route
Authors: Jabbarnia A. , Heshmati-Manesh Saeed
Published: December 2009

Mechanical alloying technique was used to produce an intermetallic based composite
powder. Mechanical activation of aluminum and nickel oxide powder mixture using a high energy
ball mill resulted in a self-propagating high temperature synthesis through which nickel oxide was
reduced by metallic aluminum and produced nickel aluminide and alumina composite powder.
Effect of milling time on crystallite sizes of the product phases was investigated. The synthesized
product was characterized by scanning electron microscope and X-ray diffraction. It was shown that
increased milling time resulted in crystallite size reduction and peak broadening in XRD patterns.
Calculation of the mean crystallite sizes of the product phases indicated that they are in nano scale.
The results were further confirmed by transmission electron microscopy.
Explosive Compaction of Metal Powder
Authors: Mohammadi K. , Dravizeh A.
Published: December 2009

In the present study ,the shock wave consolidation technique was used to produce bulk
samples from metal powders .To method of consolidation were used to produce bulk samples,
single consolidation and Two-Coaxial consolidation .after explosion ,the container tubes were
cut and density of bulk , ratio of RDX to mass of flying tube (R) ,ratio of RDX to mass of
powder(K),detonation velocity ,detonation pressure ,kinetic energy of flyer tubes and plastic
work were calculated for all tests and finally cross section of samples were observed by SEM.
The results show modified situation for Two-Coaxial consolidation by comparison in single tube
consolidation.
Study the Re-Sticky Phenomenon of Powder Metallurgy Debris in the Electrical Discharge Machining
Authors: Wang A Cheng , Cheng Ken Chuan , Lin Yan Cherng , Huang Jeng Shen
Published: December 2009

The debris re-adhering on the machining surface will affect the workpiece precision in EDM; therefore, the main purpose of this research is to study the re-sticky phenomenon of the powder metallurgy (PMM) in EDM. PMM with different melting points from 1450oC to 3410oC were used as EDM materials, the copper and the tungsten were chosen as the electrodes. The polarity in EDM was depended on the pole of the electrode. For observing the re-sticky position of the debris, the electrode was set no rotation or with 200 rpm rotational speed in EDM. The results showed that the melting point of PMM did not exceed 3000oC (PMM did not contain tungsten); the debris of PMM would not re-stick on the working surface no matter what polarity was used in EDM. However, only negative polarity can cause the re-adhesive effect when the melting point of PMM exceeded 3000oC. The debris would re-stick on any machining position when the electrode was not rotated in EDM. However, the debris would adhere on the central of the working area with 200 rpm rotational speed of the electrode.
Improving the Deposition Rate of Multicomponent Coating by Controlling Substrate Table Rotation in a Magnetron Sputtering Process
Authors: Haider Julfikar , Hashmi M.S.J.
Published: December 2009

Physical Vapour Deposition (PVD) technology, particularly magnetron sputtering process, enjoys the competitive advantages of depositing different new generation coatings (e.g., multicomponent, multilayer, graded, composite etc.) on three-dimensional objects (substrate) with excellent mechanical and tribological properties. In an industrial-scale sputtering chamber with a limited number of active magnetron sources (target) on the chamber wall, the density of coating species from different sources would not be uniform everywhere around the chamber. As a result, at a constant speed of rotating substrate table in a single revolution, the instantaneous deposition rate will be highest in front of the active targets and lowest when the substrate moves away from the active targets. In this work, a method of controlling the rotational speed (i.e., slower speed in front of active targets and faster speed in front of inactive targets in a revolution) of a substrate table installed in a magnetron sputtering chamber has been developed in order to improve the deposition rate of a multicomponent TiN+MoSx coating. The mechanical and tribological properties of TiN+MoSx coating have also been characterised to assess the beneficial effects of adding solid lubricant (MoS2) in hard TiN coating.
Experimental Determination of Cutting Temperature and Force when Turning Assab Steel with Coated Carbide Inserts
Authors: Choudhury Imtiaz Ahmed , Gan S.W. , bin Yusoff Nukman
Published: December 2009

The study is about an experimental investigation of the different factors influencing the temperature occurring at the coating/substrate and chip interface when machining Assab steels 760 and DF2 with two different coated carbide tools. Results show that tool temperature was higher when turning Assab steel 760. Temperature along the major flank face was higher that that at the minor flank. However, the magnitude of temperature was lower than expected with maximum only around 260 oC near the tool tip. The performance of Al2O3 coated WC inserts appeared to be better compared to TiN coated WC inserts. The cutting temperature was lower with alumina coated tools. While turning Assab DF2 steel, cutting temperature was lower compared to Assab 760 steel for the same coated tool.
Carbon Nanotubes Preparation Using Carbon Monoxide from the Pyrolysis Flame
Authors: Sun Bao Min , Liu Yuan Chao , Ding Zhao Yong
Published: December 2009

Carbon nanotube is a new kind of carbon material. Synthesis of carbon nanotubes from V-type pyrolysis flame is a kind of novel technique. It needs simple laboratory equipments and normal atmosphere pressure. The V-type pyrolysis flame experimental system is introduced. Carbon source is the carbon monoxide which is carried to the middle pipe of V-type pyrolysis flame combustor. Heat source is from acetylene /air premixed flame. Pentacarbonyl iron, served as catalyst, is transported by spray- pyrolysis method into the burner. The carbon nanotubes were characterized by scanning electron microscope and transmission electron microscope. The diameter of carbon nanotubes is approximate 20nm and its length is dozens of microns. The impact of the temperature, reactant composition and catalyst was analyzed to reveal the rule of carbon nanotube growth. Carbon nanotubes with good form and less impurity can be captured when the temperature was from 800°C to 1000°C and carbon monoxide/hydrogen/helium mixed gas flow was supplied. The effective diameter of pentacarbonyl iron nanoparticles is approximate from 5nm to 20nm in the process of carbon nanotube formation. Mechanism of carbon nanotube base on the V-type pyrolysis flame method was proposed. The carbon “dissolved-proliferation-separate out” theory can be used to explain how the pentacarbonyl iron catalyses carbon monoxide to form carbon nanotubes.
Preparation and Controlled-Release Analysis of Ethyl Cellulose – Moxa Leaf Powder Solution Microcapsules
Authors: Zhang Yang , Li Li , Au Wai Man , Yang Zi Ming , He Guan Ru , Deng Si Xian , Yang Zhuo Hong , Chung Joanne W.Y. , Wong Thomas K.S.
Published: December 2009

In this paper, moxa leaf powder solution microcapsules are firstly prepared by phase separation of ethyl cellulose. The microcapsule granules prepared are spherical; with good dispersibility and diameters of 10-100μm; have good effects in preservation and prolonged-releasing of active compositions in moxa leaf. The controlled-release experiment proves that after immersing in normal saline for 24 hours under constant temperature of 37°C, releasing amount of the microcapsules is less than 80%, thus the active compositions in moxa leaf still exist in the granules.
Influences of Preparative Conditions on Properties of Erythromycin-Molecularly Imprinted Membrane
Authors: Guan Ping , Hu Xiao Ling , Zhao Ya Mei
Published: December 2009

Erythromycin molecularly imprinted membranes (EM-MIMs) were prepared by wet phase inversion from imprinted polymers which were prepared by MAA as functional monomer, AN as membrane monomer and EDMA as crosslinker in the presence of erythromycin as template. The influences of the proportion of EM and MAA, cross-linking use level, different initiators and use level as well as extraction time on the imprinted sites and specific separation of EM-MIMs for EM were investigated. The results show that EM-MIMs were provided with more imprinted sites and more excellent separation properties for EM when adding MAA 0.0461mol, EM 0.724mmol, AIBN and (NH4)2S2O8 each 0.12g as initiators, and the mole ratio of EDMA and MAA at 5:1. The extraction of templates was carried out by using absolute ethyl alcohol as eluant and ultrasonic oscillating for 40min.
Research of Microprofile Extrusion
Authors: Wang Hong , Fu Zhi Hong , Yao Dong Gang
Published: December 2009

The shape change in microprofile extrusion was investigated using a capillary rheometer with two different die orifices:a trilobal and a elliptic orifice. The material used in extrusion was fiber-grade polypropylene. The result showed that during microprofile extrusion the shape of extrudate deviated greatly from that of the die orifice. The size of extrudate increased with the increase of the extrusion speed and temperature but decreased with the increase of the drawing speed. Furthermore, water cooling was found to be beneficial in reducing shape change. For the trilobal shape, the shape change of trilbolal leaf in the width direction was much larger than that in the length direction. For the elliptic shape, the shape change along the minor axis was larger than along the major axis.
Thermal Conductivity and Mechanical Properties of Silicone Rubber Filled with Different Particle Sized SiC
Authors: He Yan , Chen Zhen Chao , Ma Lian Xiang
Published: December 2009

Micro- and nano- silicone carbide particles are used as heat conductive fillers of methyl vinyl silicone rubber, and the influence of filler amount, particle size and the surface treatment of filler on the thermal conductivities and mechanical properties of silicone rubber are studied. The results show that the thermal conductivities of silicone rubber are improved, but the mechanical properties are worse with the increase of the amount of fillers. The composite filled with smaller sized silicone carbide has a better thermal conductivity than that filled with large particles in a relatively high filling fraction, and composite filled with different sized silicone carbide has different mechanical properties at the same filling amount. Treatment of fillers with coupling agent (KH-560, A-171) has active impacts on the thermal conductivity but negative impacts on mechanical properties of the filled silicone rubber.
Research of Thermal Conductivity and Tensile Strength of Carbon Black-Filled Nature Rubber
Authors: He Yan , Yin Zhong , Ma Lian Xiang , Song Jun Ping
Published: December 2009

Through measuring the thermal conductivities and tensile strength of nature rubbers filled with carbon black and comparing with each other, it is shown that the difference of carbon black particle size and the structure affects on the thermal conductivity and tensile strength of nature rubber. Thermal conductivities of carbon black-filled nature rubber are enhanced with the increase of volume fraction of filler; tensile strength of composite increases first and then decreases with the increase of carbon black volume fraction.
Preparation and Properties of Nano-Hydroxyapatite Modified Nylon Composites
Authors: Zheng Li Yun , Liu Zhi Min , Zhao Ya Jun
Published: December 2009

To enhance the mechanical property and the bioactivity of composites, nano-hydroxyapatite (n-HA) modified monomer casting nylon-6 (n-HA/N) composites were prepared by in situ polymerization. During the synthesis of n-HA/N composite, the n-HA and caprolactam were mixed, melt and placed in the field of ultrasonic radiation. The differences between composite with ultrasonic and without ultrasonic were investigated. The tensile strength and the viscosity average molecular weight of the nylon matrix were measured. The results show that the molecular weight of the nylon matrix decreased firstly and it had the lowest value when the content of nano-hydroxyapatite was 1.6 wt.%. After that the molecular weight increased and then it began to decrease when it reached the highest value. But the tensile strength of the n-HA/N composite were improved. The ultrasonic dispersion made the n-HA more evenly dispersed in the nylon and increased the mechanical properties of the n-HA/N composites significantly. The bioactivity and moisture absorption of n-HA/N composites in simulated body fluid (SBF) were examined and compared to pure nylon. What's more, Fourier transform infrared spectrometer was used to characterize the structure of the materials formed on the surface of the composite. The results showed that moisture absorption of the n-HA/N composites was lower than that of the pure nylon. After composites impregnated 16 days in SBF, a layer of carbon hydroxyapatite (CHA) with weak crystalline was formed on the surface of sample. This phenomenon showed that the n-HA/N composites have good bioactivity.
Dispersion Polymerization of Acrylamide and Acrylic Acid in Aqueous Media
Authors: Lu Jiao , Peng Bo , Li Ming Yuan , Lin Mei Qin
Published: December 2009

Dispersion polymerization of acrylamide and acrylic acid was successfully carried out in aqueous salt solutions using anionic polyelectrolytes as stabilizers. The influences of aqueous solution of salt concentration, molecular weight and concentration of the stabilizers on the apparent viscosity and stability of the dispersions, and on the molecular weight of the polymers prepared were investigated. The results showed that stable dispersions could be obtained on condition that salt concentration was between 26%~30%, concentration of stabilizers between 8%~12%, and intrinsic viscosity of stabilizers between 2.977~3.740 dL/g. With salt concentration ranging from 26% to 30%, molecular weight of products increased first and then decreased. Molecular weight of products was hardly changed when concentration of stabilizer was between 8%~12%. When intrinsic viscosity of stabilizer was between 2.977~3.740 dL/g, increase of the molecular weight of stabilizer resulted in a decrease in the molecular weight of the products.
Hyperbranched Polymers as Novel Flame Retardant Material
Authors: Borah Jyotishmoy , Lin Guang Yi , Wang Chuan Sheng
Published: December 2009

A series of aromatic hyperbranched polyethers have been synthesized from cyanuric chloride and diols by using nucleophilic displacement polymerization technique. The synthesized sulfur containing polyether was blended with commercially available low density polyethylene (LDPE) and plasticized poly(vinyl chloride) separately to improve the flame retardant property of those linear polymers. The flame retardancy of blends at different dose levels of the hyperbranched polyether with those linear polymers was investigated by measurement of limiting oxygen index (LOI) value and thermogravimetric analysis. The LOI values and TG analysis of these blends indicated that the hyperbranched polyether act as flame retardant additive.
Research of Temperature Control System Based on Fuzzy Control Algorithm for Mixer
Authors: Wang Chuan Sheng , Zhou Fu Hai
Published: December 2009

The changes of temperature in the rubber mixing process is of great significance. How to ensure the changes of temperature in rubber mixing is an important issue. The article introduces the temperature control system based on the fuzzy control algorithm. Using the host computer as the fuzzy controller, and the host computer educes the control value based on the difference between the reference input and the measure value. The system automatically discharges of high temperature water and automatically adds the appropriate amount of cooling water. The system can ensure the stability of the mixing temperature and ensure the quality of rubber mixing.
Prediction of Process-Induced Residual Stress for Laminated Composites with Metallic Plate
Authors: Shi Jun , Zeng Qing , He Xiao Dong , Wang Rong Guo , Hu Zhao Hui
Published: December 2009

The process-induced residual stress for laminated composite with metallic plate is investigated by numerical simulation during the curing process. A two-dimensional finite element model is used to compute process-induced residual stress of the laminated composite. Interface formation process between the fiber and the matrix in the longitudinal direction of composites is described by user-defined exponential function and considered in the numerical model. Numerical results show that the prediction is more accurate in the longitudinal direction of composites when the interface formation process between the fiber and the matrix is considered , which has been confirmed in the test.
Study of Rheology of Flame-Retardant Copolyester Nanocomposites
Authors: Zhao Qing Fu , Jiang Xiao Wei , Sun Shi Yuan , Qu Ming Hai , Wang Yu Zhong
Published: December 2009

A new type of nanocomposite was composited by the way of copolymerization of flame-retardant monomer DDP, PET monomer, terephthalic acid and ethylene dlycol. This article mainly researched the rheology behavior of different slices such as its apparent shear rate and shear stress and the relationship of the both in the use of capillary rheometer, and at the same time, the data of viscous flow activation energy of different sample were obtained. The result shows that under the same temperature, it is the PET/10%DDP/3% BaSO4 that is the best on the mobile performance that needs less shear stress and the temperature control in need is less strict than PFRP.
The Model Reconstruction of Carbon Black/Rubber Composites’ Heat Generation Ratio Based on Levenberg-Marquardt BP Algorithm
Authors: Yu Zhen Zhu , Ma Lian Xiang
Published: December 2009

Different temperature, different frequency, different recipe, then heat generation ratio of carbon black/rubber composites will be different. An artificial neural network model has been developed based on the analysis of the relation between carbon black/rubber composites‘ heat generation ratio and temperature,frequency.The neural network model is compared with the quadratic fitting formulae and relative errors is analyzed. The simulation results indicated the neural network model’s precision is greater than the quadratic fitting formulae’s, and artificial neural network theory can be used in the research field of carbon black/rubber composites’ thermophysical properties.
CAE Analysis of the Big-Size Injection Mold of Rear Bumper
Authors: Yin Qing Zhen , Song Rui Kun , Zhang Xiao , Qi Bin
Published: December 2009

The MPI/Cool analysis module is used to simulate and analyze the cooling system of the car’s bumper. After improvement, a comparably reasonable cooling system is designed. The situation of curling and warping of the formed bumper parts is simulated and analyzed through the MPI/Warp analysis module, the cause of the excessive warpage in the formed parts is found out and relative solutions are put forward. The forming technology of injection mold is optimized and the problem of excessive warpage is resolved.
A Study in the Adsorption Behaviors of Cr (VI) on Crosslinked Amphoteric Starches Synthesized through Using the Microwave Radiation Method
Authors: Zou Li Xia , Liu Qing Cheng , Xu Qiong , Rong Jing Hua
Published: December 2009

Crosslinked amphoteric starches (CAS) with quaternary ammonium cationic and carboxymethyl anionic groups were prepared by a microwave radiation method. Their adsorption behavior for Cr(VI) was investigated. The results showed that high the degree of substitution (DS) of modified starch was favorable to the synthesis by the microwave heating and crosslinked amphoteric starches prepared with higher the adsorption capacity than by the drying reaction. The adsorption capacity increases with the increasing cationic groups and decreased with increasing degree of substitution of anionic groups. The adsorption capacity was found to follow the Langmuir isotherm.
Preparation of Polyacrylamide Nanofibers by Electrospinning
Authors: Liu Li , Gu Wei Wei , Xv Wen Ting , Xiao Chang Fa
Published: December 2009

Polyacrylamide (PAM) nanofibers was spun by electrospinning. In order to increase the molecular weight of the PAM, It has been cross linked by Glutaraldehyde solution. By means of scanning electron microscopy (SEM), the effect of electrospun technological parameters on the fibers’ morphology were researched. The parameters include the concentration of PAM spinning solution, the applied voltage and tip-collector distance (TCD). The PAM nanofibers of uniform thickness with the fibers’ diameter distribution of 80 ~ 160nm were got under the conditions as followers: the concentration of 16 wt.%, applied voltage of 23 kV, the TCD of 13cm.
Studies on the Properties of Banana Fibers-Reinforced Thermoplastic Cassava Starch Composites: Preliminary Results
Authors: Mo Xian Zhong , Zhong Yu Xiang , Liang Chun Qun , Yu Shu Juan
Published: December 2009

Banana fibers received four treatments, namely squeezing, alkali and hydrogen peroxide treatment, washing with water, and drying. Thermoplastic starch composites was prepared with glycerol as the plasticizer, banana fiber as reinforcement and thermoplastic cassava starch as matrix. The banana fiber could increase processing torque highly, while the effects of fiber contents on peak torque at 3min was so obvious. X-ray diffractograms illustrated that with increasing fiber content, cellulose crystallinity at 22.5° gradually got stronger but starch crystallinity at 20° almost didn’t. SEM micrographs showed good dispersion and adhesion between starch and fiber. Studies in the dependence of mechanical properties of reinforced TPS on the contents of fiber that with increasing fiber content from 0 to 20phr, the initial tensile strength was trebled up to 14.46 MPa, while the elongation at break was reduced from 68 to 13%. TG mass loss curves showed that thermal stability of this composites had great improved under 500°C.
Expert System of Precise Injection Molding Process Optimization Based on Moldflow Software
Authors: Xie Peng Cheng , Du Bin , Yan Zhi Yun , Ding Yu Mei , Yang Wei Min
Published: December 2009

An expert system of precise injection molding process optimization based on Moldflow software was set up in this paper. Expert system of precise injection molding process optimization based on Moldflow-MPI module consist of optimization of packing curve, analyzer of parallelism and coaxiality, analyzer of process optimization and integrative forecaster of weld line. The system can be used in the process optimization of precise injection molding, the forecast and control of product properties, and the flaw elimination of product molding.
Structure and Property of PGMA/Wood Composite
Authors: Li Yong Feng , Liu Yi Xing , Shi Jiang Tao , Li Gang
Published: December 2009

In order to prepare a wood-based composite material which, as a type of multifunctional and natural bio-based material, possesses satisfactory mechanical properties, excellent durability (i.e., decay resistance and dimensional stability), and Aenvironmental characteristic, the study presents a new method which is based on the cellular structure of wood by initiating polymerizable monomers for in situ polymerization. Glycidyl methacrylate (GMA) as a multifunctional and polymerizable monomer was chosen, and impregnated into the porous structure of wood. After a thermal-catalyst process, the wood-based composite, PGMA/Wood, was prepared. The structure of this material was analyzed by SEM, FTIR and XRD; and its performance was also determined. The analyzing results show that GMA not only polymerized in the cellular structure in a solid form and amorphous form, which fully and uniformly filled in wood cell lumen, but also sufficiently grafted onto wood cell walls in a chemical level, resulting in tight contact between wood cell walls and resultant polymers (PGMA) without any obvious cracks. The test results of mechanical properties show that the modulus of rupture (MOR), modulus of elasticity (MOE), compression strength, and hardness of PGMA/Wood increased by 82%, 122%, 139%, and 348% over those of untreated wood, respectively. The test results of durability show that the dimensional stability and decay resistance of PGMA/Wood improved 44% and 91% than those of untreated wood, respectively. Such composite could be widely applied in the fields of construction, furniture and traffic.
Effect of Vulcanization and Shaping Process on Radial Force Variation of TBR Tire
Authors: Fu Ping , Wang Chuan Sheng , Zhang De Wei , Bian Hui Guang , Pu Zhe
Published: December 2009

The study was based on researching various parameter of vulcanization shaping process for effect of radial force variation (RFV).The experimental results showed that reducing the first and second shaping pressure, and increasing hole diameter of N2 on curing bladder, and extending times of discharged N2 in shaping process, and reducing pressure of expanded bladder at the moment of closing mold, could reduce RFV of TBR tire and improve uniformity of tire and provide base data of product process.
Periodic Mixing Performance in a Square Cavity for Different Frequencies
Authors: Xu Bai Ping , Liu Yue Jun , Qu Jin Ping
Published: December 2009

Based on vortex-velocity method, the control equations of laminar flow of high vicious fluid in a square cavity driven by the continuous periodic vibration motion of upper and bottom lids are derived. And then the numerical solution of the transient velocity field which is based on the superposition method is obtained by using the finite volume method. The motion of the passive tracer is numerically integrated by the fourth order adaptive Runge-Kutta scheme. The results show that when the frequency is below 0.1Hz, the mixing is controlled by the globally chaotic mixing. While the frequency increases to between 0.1 Hz and 0.5 Hz, the quasi-periodic islands occur in the region of chaotic motion. After the frequency exceeds 0.5Hz, the mixing degenerates into the regular laminar mixing. Through the contrasts of Poincaré sections, it is proved that the frequency not only has the effect on the scales of KAM islands, but also dominates the mixing transition from the globally chaotic mixing to the traditionally regular laminar mixing.
Experiment Research on Maximum Power of the VIC Mixer
Authors: Yang Fu Qin , Wang Chuan Sheng , Song Guan Ying , Xu Jun
Published: December 2009

The relationship of maximum power relative to rotor clearance, filling factor, rotor speed, ram piston pressure and cooling water temperature was studied for the VIC(Variable Intermeshing Clearance) mixer. The study result by single-factor experiment method showed that in certain extent, the larger the value of rotor clearance, filling factor, rotor speed, ram piston pressure, the larger the value of maximum power would be; the smaller the value of cooling water temperature, the larger the value of maximum power would be. And the study result by quadratic orthogonal regression combinational design gave the mathematical expressions of maximum power.
Research on Tribological Properties of Micro-Vehicle Clutch’s Friction Material
Authors: Lv Jun Cheng , Mo Yi Min , Pan Li Na
Published: December 2009

To explore the substantial cause of the early abnormal wear of micro-vehicle clutch’s friction material, the sample test aimed at studying the tribological properties of micro-vehicle clutch’s friction material is designed, according to GB/5763-98 national test standards. The broken line graph of samples’ friction coefficient on and wear rates in different working conditions are obtained. There are two types of working conditions. One is the same line speed and different working loads of samples, and the other is the same working load and different line speeds. Combined Scanning Electron Microscopy (SEM)’s observation with tribological principle, the sample test result is analyzed, thus obtaining the changing rules of the materials’ friction coefficient and wear rates at different temperatures, working loads and line speeds.
Experimental Study on Mold Separations of Plastic Injection Molding Machines with Different Clamping Units
Authors: Zhang Pan Pan , Xie Peng Cheng , Hua Dai , Yang Wei Min
Published: December 2009

The plastic injection molding is widely used for the manufacturing of complicated-shaped and high value-added products. The plastic injection molding machine is the most important equipment for the industry. This paper focuses on the mold separation (MS) of the injection molding machines. The characteristics of the MS of injection molding machine with different clamping units are systemically analyzed, the five-hinge joint-double toggle clamping unit and the direct hydraulic pressure clamping unit included. The study points out there are several typical differences between the different clamping units. Meanwhile, it shows there is a linear relation between the MS value and the product weight, and explains why the MS signal can be used to control the injection molding process.
The Melting and Recrystallization Behavior of Poly(ethylene Terephthalate)/SiO2 Nanocomposites Studied by Step-Scan DSC
Authors: Liu Chen , Zheng Kang , Yao Xia Yin , Zhang Xian , Liu Xiang Lan , Wang Ruo Xi , Tian Xing You
Published: December 2009

The melting and recrystallization behavior of Poly(ethylene terephthalate) (PET)/SiO2 nanocomposites after isothermal crystallization from the melt was studied by Step-scan differential scanning calorimetry (SDSC). The influence of SiO2 contents, crystallization temperature and crystallization time on the melting process were examined. Two melting endotherms(in the SDSC CP.A curves, reversible part) and one recrystallization exotherm (in the SDSC CP.IsoK curves, irreversible part)of PET/SiO2 nanocomposites after isothermal crystallization were observed during the melt process. This ascribes to the melting-recrystallization mechanism .The low temperature endotherm attributes to the melting of primary crystal formed during the isothermal treating and the high temperature endotherm resulting from the melting of recrystallization materials. The reason why more recrystallization happened with the increase of SiO2 content was given and the process of recrystallization was described in detail. The effects of crystal perfection and recrystallization were minimized by increasing of crystallization temperature and time.
Dynamic Compressive Response and Failure Behavior of Basalt Fibers Polymer Functional Composites Embedded with ZnO Whiskers
Authors: Zhou Wei , Wen L.J. , Zhang Xiao Xia , Wang Xi , Rong Ji Li , Jin Hai Bo
Published: December 2009

A type of basalt fibers polymer functional composites embedded with ZnO whiskers was prepared. The as-prepared composites exhibited good microwave absorption properties after the dispersion of ZnO whiskers in resin. The dynamic compressive properties of composites were investigated by the split Hopkinson pressure bar (SHPB) system. The macro- and micro-fracture morphology of composites was obtained by the scanning electron microscope (SEM). The experimental results showed that the as-prepared composites have excellent mechanical properties, and the compressive properties could be significantly affected by the strain rates in the in-plane direction, as well as in the normal direction. As the strain rate increased, the higher strength and elastic modulus are obtained. Under the dynamic compressive load in the normal direction, the main failure mode of composites is pure compression. On the other hand, longitudinal splitting and delamination of composites could be induced when loaded in the in-plane direction. The micro- interfacial crack, fiber fracture and plastic deformation of resin could be observed from the morphology of fractured composites.
Influence of Mineral Admixtures on the Performance of Polymer Modified Porous Concrete
Authors: Xu Fang , Zhou Ming Kai , Shen Wei Guo , Li Bei Xing
Published: December 2009

In order to improve the performance of polymer modified porous concrete (PMPC), the mineral admixtures (MAs) including fly ash (FA) and silicon fume (SF), are added in the concrete. In this paper, the optimum dosage of the MAs, the influence of the MAs on the strength performance, permeability performance and the surface functional performance of PMPC are studied. The microscopic test of SEM is used to explore the microscopic structure of PMPC. The test results indicate that: the dosage of 10% FA or of 6% SF is the optimum dosage, while the 28d compressive strength can reach 24MPa and 43MPa, respectively, the 28d flexural strength can reach 5.2MPa and 5.3MPa, respectively, and the permeability coefficient can reach 0.36cm/s and 0.32cm/s, respectively. The surface structural depth can reach more than 1mm and the slide resistance coefficient can reach more than 40BPN, which can conform to the standard of JTG F30-2003. The Contact Element Model is proved to conform to the structural features of PMPC. With the microscopic test, as the addition of the polymer and MAs, the internal micro-cracks and non-hydrated cement particles in the interfacial transition zone (ITZ) are covered by the cement paste and polymer films. The contact area, the mechanical property and durability of PMPC can be improved.
Carbon Nanofibers from Pyrolysis Flame and Research on the Affecting Factors
Authors: Liu Yuan Chao , Sun Bao Min , Shan Ti Kun , Ding Zhao Yong
Published: December 2009

Synthesis of carbon nanofibers from the V-type pyrolysis flame is a new method and it has wide application prospects. It needs simple laboratory equipments and normal atmosphere pressure. The V-type pyrolysis flame experimental system is introduced, involving V-type pyrolysis flame burner, mass flux controllers, sampling substrate etc. The carbon nanofibers were characterized by scanning electron microscope and transmission electron microscope. Carbon nanofibers with less impurities and high quality can be captured when the temperature was from 800 to 880°C, austenitic stainless steel type304 was served as sampling substrate, nickel nitrate was served as catalyst precursor and sampling time was 5 minutes. The carbon nanofibers are from 100 to 200 nm in diameter and dozens microns in length. The average diameter of catalyst particles is approximately from 20 to 50 nm. The effects of temperature, sampling substrate materials, sampling time and catalyst were analyzed. The temperature determined the diameter and shape of carbon nanofibers. The austenitic stainless steel type304 substrate containing nickel is in favor of synthesis of carbon nanofibers. The number of carbon nanofibers got more and more while the diameter got thicker firstly and then had little change with the sampling time increased within 5 minutes. In addition, experimental results also indicated that carbon nanofibers had much impurity and worse morphology if the diameter of catalyst particles was above 50nm.
Calculation of Fracture Toughness for Hydrogen Embrittlement in a Pressure Vessel
Authors: Mahdavi Ehsan , Mashhadi Mahmoud Mosavi
Published: December 2009

An analytical procedure is developed to design and predict the behavior of a pressure vessel. If a pressure vessel contains hydrogen, it is difficult to predict what will happen in the future. In this study, this is accounted for and the stress intensity factor for mode-Ι is calculated because the main factor controlling mass diffusion, as a driving force, is related to the stress in this mode. Also, it is known that the stress intensity factor depends upon concentration. The main challenge in hydrogen embrittlement is the prediction of crack growth and the estimation of lifetime for a pressure vessel. This paper investigates the effect of hydrogen diffusion upon crack in a pressure vessel by using numerical finite-element simulations. The fracture behavior of the alloy as related to hydrogen embrittlement was also studied. The computational simulations involved sequentially-coupled stress and mass-diffusion concentrations at the crack tip. Although there have been various previous works in this area, most of them have been experimental estimates of hydrogen diffusion. In this paper, we calculate the stress intensity factor by using the finite-element method (FEM) and use mathematical analysis simultaneously. The analytical method alone could not be used because the mass diffusion has special characteristics. That is, the treatment of diffusion is different at each step. We conducted finite-element modeling simulations of the intergranular fracture of alloy X-750 due to hydrogen embrittlement. Sequentially coupled stress and mass diffusion determinations were carried out in order to determine crack tip stresses and hydrogen diffusivity in the crack-tip region. Good qualitative agreement between the FEM modeling and the analysis was observed.
Acoustic Emission during Isothermal Oxidation of 2.25Cr-1Mo Steel
Authors: Jha B.B. , Mishra Barada Kanta , Ojha S.N.
Published: December 2009

Acoustic emission (AE) signals, obtained during the isothermal oxidation of 2.25Cr-1Mo steel at 773 K, 873 K, 973 K and 1073 K, have been analyzed. The results indicated that the rate of occurrence of AE events and consequently the total number of AE events generated during isothermal oxidation at these temperatures increased with an increase in the oxidation rate. Variation in the temperature of oxidation did not show any variation in the root mean square (RMS) level of the AE signals. The b-parameters obtained from a logarithmic cumulative amplitude distribution plot indicated that the strength of the AE signals did not change during isothermal oxidation carried out at these temperatures. Different event rates, and consequently the difference in the total number of AE events generated during isothermal oxidation at these temperatures, are indicative of the increased rate of energy release associated with the growth of oxide layers formed at higher temperatures. The rate of energy release has been found to be higher for higher temperatures of oxidation.
Degree of Vinyl Conversion, Polymerization Shrinkage and Stress Development in Experimental Endodontic Composite
Authors: O'Donnell Justin N.R. , Skrtic Drago
Published: December 2009

This study explores degree of vinyl conversion (DVC), polymerization shrinkage (PS) and shrinkage stress (PSS) of the experimental amorphous calcium phosphate (ACP) composites intended for use as an endodontic sealer. Light-cure (LC), chemical cure (CC) or dual-cure (DC; combined light and chemical cure) resins comprised urethane dimethacrylate (UDMA), 2-hydroxyethyl methacrylate (HEMA), methacryloyloxyethyl phthalate (MEP) and a high molecular mass oligomeric co-monomer, poly(ethyleneglycol)-extended UDMA (PEG-U) (designated UPHM resin). To fabricate composites, a mass fraction of 60 % UPHM resin was blended with a mass fraction of 40 % as-made (am-ACP) or ground ACP (g-ACP). DVC values of copolymer (unfilled UPHM resin) and composite specimens were determined by infrared spectroscopy. Glass-filled composites were used as controls. PS and PSS of composites were determined by dilatometry and tensometry, respectively. LC copolymers attained extraordinary high DVC values at 24 h post-cure (95.7 %), compared to CC (52 %) and DC (79.3 %) copolymer specimens. While the DVC values of LC and DC am-ACP composites were reduced between 5 and 10 %, DVC values of DC g-ACP composites increased almost 8 % compared to the corresponding copolymers. High DVC attained in LC composites was, expectedly, accompanied with high PS values (on average 7 vol%). However, PSS developed in LC and especially DC composites did not exceed PSS values seen in other UDMA-based composites. Based on this initial evaluation, it is concluded that, DC, g-ACP filled UPHM composite shows promise as an endodontic sealer. However, further physicochemical evaluations, including water sorption, mechanical stability and ion release as well as a leachability studies need to be performed before this experimental material is tested for cellular responses and, eventually recommended for clinical utility.