bluuebunny/crossref_metadata_2025 huggingface dataset:
Sodium Lignosulphonate-Polyvinyl Alcohol Bioadsorbent: Synthesis, Characterization and Adsorption for Pb (II)
Authors: Luo Xiao Qing , Lin Xiao Yan , Luo Xue Gang , Chen Yan
Published: August 2009

A novel sodium lignosulphonate (SLS)-polyvinyl alcohol (PVA) spherical macroporous bioadsorbent (SLSP) was synthesized by reversed phase suspension polymerization. Comparing with powdery and high water solubility SLS, this new spherical bioadsorbent exhibited relative stability under static force. SEM and FTIR proved the cross-linking of SLS and PVA. TG curves of SLS and SLSP indicated that the thermal property of SLS had been improved by cross-linking modification. Meanwhile, comprehensive adsorption study of Pb (II) on this bioadsorbent was conducted regarding the effects of time, initial PH and initial Pb (II) concentration. 90% of Pb (II) from aqueous solution could be removed by 0.4g of the adsorbent at 25°C for less than 3h. The adsorption process was determined to be consistent with the Langmuir isotherm.
Synthesis and Thermal Properties of Etherified Konjac Glucomannan
Authors: Wu Qiang , Lin Xiao Yan , Luo Xue Gang , Chen Yan
Published: August 2009

A novel etherified KGM (EKGM) was synthesized with Konjac glucomannan (KGM) and 1-bromopropane in Lithium chloride/dimethyl sulfoxide (LiCl/DMSO). The EKGM was characterized by FT-IR, DSC and TG. The IR of EKGM showed that –OH stretching vibration band decreased and the C–H and C–O–C stretching vibration bands increased comparing with the unmodified KGM, which was indicating that KGM had been etherified. The DSC thermograms showed that an obvious glass transition of EKGM appeared and its glass transition temperature (Tg) decreased with the increasing of Pr/OH ratio. And it was also found that the EKGM had a higher decomposition temperature than unmodified. Meanwhile, it was proved that the EKGM was a good hydrophobic polymer and dissolved in some organic solvent easily.
Development of Environmental-Friendly Water-Retentive Asphalt and its Characteristics
Authors: Lee Sang Ho , Pyun Hee Bum , Gee Chae Sung , Park Jong Bin
Published: August 2009

Urban area may be warmer than surrounding regions due to asphalt and concrete for roads, buildings, and other artificial structures. Especially, pavements have become an important contributor to this effect by altering land-cover over significant portions of an urban area. Therefore, researchers have studied ways to reduce the heat island effect such as cooling pavement, porous pavements such as water-retentive or water absorbing pavements. Accordingly, this study aims at the development of water-retention asphalt pavement for urban areas in order to solve problems related to the distortion of water cycle and the heat island phenomena. Experimental results indicated that asphalt pavement using developed water retaining material was effective to decrease its surface temperature compare to other pavements. A correlation between air temperature and surface temperature of the pavement was obtained to estimate the efficiency of the developed pavement materials.
Field Applications of Urban Non-Point Source Pollutant Reducing Treatment System with the Expanded Polypropylene(EPP) Media for Treating PAHs from Road Runoff
Authors: Yun Sang Leen , Kang Sung Won , Kim Seog Ku , Kwak Pill Jae , Ahn Jae Hwan , Oh Hye Cheol
Published: August 2009

Since the non point source is unspecified and estimating the degree of occurrence or identifying causing factors are difficult, it is not easy to control.
Road runoff is considered a major source of pollution in developed urban sites. Road surfaces accumulate significant quantities of pollutants including nutrients, heavy metals and polycyclic aromatic hydrocarbons(PAHs). Many studies have characterized the constituents of stormwater. These constituents include polycyclic aromatic hydrocarbons(PAHs).
Urban non-point source pollutant reducing treatment System is a part of the road runoff treatment which expanded polypropylene(EPP) media with a large surface area to treating the first flush of stormwater from road in field. Urban non-point source pollutant reducing treatment System consist of a container, a total 8.89m2 volume(3.6m(L), 1.3m(W), 1.9m(H)) which is made up of two element; sedimentation chamber of storage tank and filter tank.
Under the operating conditions with 0.55h hydraulic retention time(HRT) and a capable of treating a maximum road runoff of 9.5m3/hr, the mean residual total PAHs were 0.699~1.339 µg /L and the percentage mean removal values were 61.4~69.7%, respectively.
Effects of Pair-Mineralizer on Burnability of Clinker and Formation of Mineral
Authors: Kwon Woo Teck , Kim Y. , Lee Yoon Joo , Kim Soo Ryong , Ha Sang Wook
Published: August 2009

The effects of the pair-minerializer (CaSO4,-CaF2) on the burnability of clinker and the formation of mineral are investigated. As experimental results, the addition of F as pair-mineralizer, the burnability of clinker was improved. Especially, the addition of F and SO3 components simultaneously as pair-mineralizer, total amount of free lime in clinker is rapidly decreased compared with the value which mineralizer was added separately. In case of adding K2O only to the raw mixes, the amount of free lime is increased. However, if alkali (K2O) and pair-minerializer (CaSO4,-CaF2) were added simultaneously, the produced amount of clinker mineral is increased due to the formation of stable calcium langbeinite by the combination of alkali (K2O) and sulfate
Ironmaking Process Parameter Analysis and Optimization for the Blast Furnace
Authors: Yang Shuang Ping , Song Yong Hui , Xin Liu Hua
Published: August 2009

With practical data of the BF ironmaking from Jiuquan Iron&Steel Cooperation Ltd. (JISC), taking the quality of pig iron as evaluation indicator, mathematical models based on the least square regression and partial least square regression were set up respectively by co-relation analysis of feeding-to-product interval of the BF processing. The calculation results showed that the reasonable description can be obtained by the partial least square regression model; and 10 of 29 parameters with obvious impact on the BF operation were listed accordingly. Meanwhile, an optimal group of parameters was found by genetic algorism calculation method. The optimal index of the group was 99.13％. This study is beneficial to the improvement of feeding adjustment and optimal operation of BF ironmaking.
Collapse-Type Shrinkage in Plantation-Grown Eucalyptus Cells When Subjected to Heat-Steam Treatment
Authors: Wu Yi Qiang , Kazuo Hayashi , Cai Ying Chun
Published: August 2009

Collapse-type shrinkage in plantation-grown Eucalyptus cells is a bottleneck to severely restrict its high-effective utilization as environment-friendly solid-wood products. So, measurement of collapse-shrinkage parameters on seven species of Eucalypts (Eucalyptus urophylla, E.grandis, E.urophylla×grandis, E.grandis ×urophylla, E. dunnii, E. cloeziana and E. pellita) have been carried out under three kinds of treated patterns (heating, steaming and combined treatment) by means of image analysis technique. The results indicated that the total shrinkage and residual collapse increase obviously with heating temperature and steaming time for five species of low-density eucalypts(E.urophylla, E.grandis, E.urophylla×grandis, E.grandis ×urophylla and E. dunnii), while increase slightly for other two species of higher-density Eucalypts (E.cloeziana and E.pellita). Combined treatment has not made the total shrinkage and residual collapse take on the additive trend, especially for higher-density Eucalyptus. Therefore, the results will provide the important practical significance for the reasonable processing of plantation-grown eucalypt wood.
The Effect of Aging on Synthesis of Zeolite at High Temperature
Authors: Yoo Yeong Seok , Ban Hyo Jin , Cheon Kyeong Ho , Lee Jae Ik
Published: August 2009

Zeolite are used as adsorbent, catalyst and ionexchang material. But it limited to extend the usage of the zeolite since almost zeolite synthesized by hydrothermal method. The purpose of this study was to synthesis zeolite by calcination at high temperature due to extend the application of zeolite, as ceramics process. The effect of aging temperature and time, crystallization temperature on the synthesis of zeolite has been studied. Aging was performed at room temperature~70°C during 0~3days. After aging, zeolite precursor sinter for 1 hours at 300, 400, 500°C in furnace. The resulting materials were characterized by XRD, TG, SEM
When the aging time is less than 1 day zeolite was not synthesized. But zeolite A obtained from precursor of aging time is more than 1 day at all firing temperature. As a result the aging time and aging temperature is increased, the zeolite synthesis time is decreased. Therefore aging is benefit process on synthesis of zeolite at high temperature.
Explicit Finite Element Analysis of the Plunge Stage of Tool in Friction Stir Welding
Authors: Li Wen Ya , Yu Min , Li Jing Long , Gao Da Lu
Published: August 2009

The investigation of the plunge stage of the tool during friction stir welding (FSW) is the basis of understanding the nature of FSW, which is especially important for friction stir spot welding. In this study, the plunge stage of FSW tool was numerically examined by dynamic explicit finite element method with more attention to the temperature evolution. It was found that the high temperature region around the stirred zone extended with increasing the rotation speed. The heat affected zone expanded with the increase of inserting time, but the highest temperature around the stirred zone changed little. The range of the stirred zone changed little with the variations of the rotation speed and inserting time. The simulation result on the temperature field was in comparable agreement with the experimental one.
Evaluations of Hydrogen Permeation on γ-Al2O3 Synthesized by Sol-Gel Process
Authors: Park Ji Hee , Jung Mie Won , Hong Tae Whan
Published: August 2009

The purpose of this work was hydrogen permeation of ceramic or metal/ceramic membrane using γ-Al2O3 by synthesizing. The γ-Al2O3 was synthesized by using the sol-gel process with aluminum isopropoxide and primary distilled water as the precursor and solvent. The γ-Al2O3-based membranes were prepared using HPS. The phase transformation, thermal evolution, surface are and morphology of γ-Al2O3 and γ-Al2O3-based membranes were characterized by XRD, TG-DTA, BET and FE-SEM. The hydrogen permeation of γ-Al2O3-based membranes was examined at room temperature comparing with other paper using nickel composited membrane on alumina ceramic support.
Practical Recycling Application of Power Plant Coal Ash for High Performance Shotcrete Material
Authors: Park Cheol Woo , Kim Kyung Nam
Published: August 2009

This study intends to increase the consumption of coal ash which is an industrial by-product from power plants. The coal ash used to be deposited in the ground and its recycling has been very poor comparing to the produced amount. This study aims to enhance practical application of coal ash as a shotcrete construction material. Derived were optimum mix proportions for high performance shotcrete using coal ash. In order to enhance long term performance, silica fume was also added. Experimental variables included replacement ratio of silica fume and coal ash. Compressive strength and potential hazardous contamination to soil were the primary factors in the performance evaluation. From the test results, when fly ash was replaced up to 10% of the cement, most required specifications were satisfied. Hazardous material content was shown to be well below the specifications. Therefore, when appropriate caution in handling is given in the field, it is strongly anticipated to increase the coal ash recycling as a shotcrete construction material.
Recycling of Waste Concrete and Fly Ash for Recycled Aggregate Concrete: Fundamental Characteristics Evaluation
Authors: Park Cheol Woo
Published: August 2009

As the amount of waste concrete has been increased and recycling technique advances, this study investigates the applicability of recycled concrete aggregate for concrete structures. In addition fly ash, the industrial by-product, was considered in the concrete mix. Experimental program performed compressive strength and chloride penetration resistance tests with various replacement levels of fine recycled concrete aggregate and fly ash. In most case, the design strength, 40MPa, was obtained. It was known that the replacement of the fine aggregate with fine RCA may have greater influence on the strength development rather than the addition of fly ash. It is recommended that when complete coarse aggregate is replaced with RCA the fine RCA replacement should be less than 60%. The recycled aggregate concrete can achieve sufficient resistance to the chloride ion penetration and the resistance can be more effectively controlled by adding fly ash. It I finally conclude that the recycled concrete aggregate can be successfully used in the construction field and the recycling rate of waste concrete and flay ash should be increased without causing significant engineering problems.
Tensile Properties of AZ91D Magnesium Alloy Coated by Plasma Electrolytic Oxidation
Authors: Lee Du Hyung , Kim Bo Sik , Chang Si Young
Published: August 2009

Tensile properties of AZ91D magnesium alloy coated by Plasma Electrolytic Oxidation method for various coating times were investigated. The coatings on AZ91D magnesium alloy showed porous microstructure, and became thicker with increasing the coating time. After tensile test, the coated AZ91D magnesium alloy had lower tensile strength and elongation than the uncoated one. The tensile strength and elongation decreased with increasing the coating time, while the proof stress was almost no changed. The uncoated AZ91D magnesium alloy revealed ductile fracture surface. As the coating time increased, however, the fracture surface was changed to brittle fracture morphologies.
Study on Micro-Hardness and Electrical Conductivity in as Cast Cu-Fe-P Alloys
Authors: Gou Bin , Lee Je Hyun , Gu Ji Ho , Euh Kwang Jun , Han Seung Zeon
Published: August 2009

The micro-hardness and electric conductivity was studied in as cast alloy Cu-Fe-P alloys which were solution treated at 980°C and aging treated at 400-800°C for 1-20 hours. The micro-hardness peak value was 180 HV and the conductivity peak value was 65% IACS. The hardness and the electric conductivity all depended on precipitation principally. The addition of C in Cu-Fe-P alloy reduced the grain size and accelerated precipitation which resulted in enhancing hardness and electric conductivity together.
Numerical Simulation of Perforated Hollow Sphere Structures (PHSS) to Investigate Mechanical Properties
Authors: Öchsner Andreas , Hossein Hosseini Seyed Mohammad , Merkel Markus
Published: August 2009

This paper investigates the uniaxial mechanical properties of a new type of hollow sphere structures. For this new type, the sphere shell is perforated by several holes in order to open the inner sphere volume and surface. The mechanical properties, i.e. elastic properties and initial yield stress, of perforated hollow sphere structures in a primitive cubic arrangement are numerically evaluated for different hole diameters and different sphere wall thicknesses.
Research on Magneto-Rheological Fluids Torsional Damper and Control System Applied to Controlling Carbon Fiber Strain
Authors: Peng Yong , Jiang Zhuang De , Duan Zheng Yong
Published: August 2009

One fiber stain measure and control system has been designed to meet the problem that the magnitude and uniformity of the fiber strain directly determine the properties and longevity of the carbon fiber continuous sucker rod during the pultrusion process. In this system, there are 2 key technologies. The first one is the sensor that is used to measure the micro bend strain of the carbon fiber during the pultrusion process, designed base on fiber micro-bend principle, using silicon film as sensitive element and fabricated by silicon integrated circuit technology and three dimensional processes. Another is the executive unit of the system: Magneto-rheological Fluids torsional damper, which is designed base on one type of intelligent material named Magneto Rheological Fluids which can change its viscosity in millisecond according to the magnetic strength around it. So this paper provides a technical means to ensure the quality of the pultrusion process applied in fabricating the carbon fiber continuous sucker rod.
Effect of Deformation Parameters on Deformation Behavior of Ti14 Alloy during Semi-Solid Compression
Authors: Chen Yong Nan , Wei Jian Feng , Zhao Yong Qing , Ma Xue Dan
Published: August 2009

The effects of the process parameters on the deformation behavior of Ti14 alloy have been investigated by compressive tests, at temperature between 1000°C and 1150°C and with strain rates from 5×10-3 S-1 to 5S-1. The results revealed that deformation temperature and strain rate have significant effect on the peak flow stress, the flow stress decreases. The response time required by deformation was affected by the strain rates and liquid fraction was done by the temperature. At higher temperature, transforms deformation mechanism was changed from sliding between solid particles to flow of liquid incorporating solid particles by the change of the liquid fraction.
Precipitation Prediction and Experimental Clarification of Mg-Al-Sn System
Authors: Kim Jin Young , Kim Eun Jung , Han Jeong Whan
Published: August 2009

Phase equilibrium of the Mg-Al-Sn alloy system was calculated in detail by utilizing phase diagram calculation commercial package and other thermodynamic data for Mg alloys. The calculated phase diagrams were compared with the DSC results for the alloys of Mg-3wt%Al-3wt%Sn. The solidification and precipitation process of Mg-3wt%Al-Xwt%Sn were analyzed. The detailed comparison strongly supports the reliability of the selected thermodynamic description based on the results of thermodynamic calculation. It is clarified that when the Mg-Al-Sn alloy ends its solidification and cools down continuously, the phase Mg2Sn precipitated first from solid solution of magnesium, and then the Mg17Al12 phase precipitated at relative lower temperature. This is shown that the calculation phase diagram method considerably reduces the effort of alloy design and that the reliability of the results is high.
Synthesis and Properties of Polyurethane-Based Actuator with Poly(dimethyl Siloxane)
Authors: Jo Nam Ju , Lim Do Hee , Song Young Min , Bark Geong Mi , Lee Won Ki
Published: August 2009

This paper investigated the use of electrostrictive polymers with compliant electrodes as a means of actuator. In many electrostrictive materials, especially polyurethane (PU) can produce large deformation and force because of its low elastic modulus.The electromechanical response is mainly due to Maxwell stress effect and electrostriction effect. When a thin film of dielectric elastomer is applied to an electric field, it will experience Maxwell stress caused by interactions of free charge between the electrodes and electrostriction caused by the reorientation of polar phase in the material. In this work, PU was composed of the soft segment with poly(dimethyl siloxane) (PDMS) and the hard segment with 4, 4’-diphenylmethane diisocyanate. Also the hard segment content of synthesized PU was controlled at 20, 25, 30, and 35wt%. To conclude, mechanical properties increased with the increase in hard segment contents. However actuation test showed that the deformation was decreased as hard segment contents increased.
Electrical Property Characterization of Plasma Sprayed Polycrystalline Silicon
Authors: Niu Ya Ran , Liu Xuan Yong , Zeng Yi , Zheng Xue Bin , Ji Heng , Ding Chuan Xian
Published: August 2009

Silicon-based materials have been widely applied in industrial fields, such as microelectronic and solar power, for the specific electronic properties. In the present work, free-standing thick silicon coatings were fabricated by air plasma spraying (APS) and vacuum plasma spraying (VPS) technologies. The microstructure and electrical property of the coatings were characterized. It was found that the electrical resistance of APS-Si coating was higher than that of VPS-Si coating. The impedance spectroscopy results showed there was significant difference in impedance curves of APS-Si and VPS-Si coatings. The grain boundary semicircle appeared in the plot of VPS-Si coating, while did not appeared in that of APS-Si coating. It was thought that the electrical property difference of the two kind coatings was related with the oxidation and microstructure difference of the coatings.
Development of Composite Binder System for Shell Mold in Precision Casting of Thin Stainless Steel
Authors: Lee Woo Ram , Kim Eun Hee , Kwon Jae Young , Kim Jae Hyun , Jung Yeon Gil
Published: August 2009

New composite binder systems have been developed to improve strength of shell mold and to decrease processing time, as functions of dipping time and binder composition, which is compared with the conventional binder system. The new binder systems were prepared by mixing tetraethyl orthosilicate (TEOS) and polydimethyl siloxane (PDMS) as precursor of SiO2 and sodium methoxide (NaOMe) as precursor of NaO2. The samples of shell mold were dipped into the prepared binder systems, and then heat-treated at 1000°C for 1 hr. The fracture strength is sharply enhanced in the new binder system owing to the increase of penetration depth with the dipping time, whereas the conventional binder system is modestly increased even in the dipping time of 2 hr. The new binder system with 7.6 wt% PDMS shows the highest nominal strength, showing a nominal value of 16 GPa. When only PDMS as precursor of SiO2 was used in the new binder system, the increase of viscosity by PDMS causes a larger scattering in the strength value. The strength could be controlled with the dipping time and molecular weight, showing the lower nominal strength values at the dipping time of 0.5 hr and in the low molecular weight of TEOS/NaOMe. The relationship between strength and binder composition is discussed, based on the microstructures before and after heat-treatment.
An Investigation on Erosion Wear Characteristics of SiC Particle Reinforced Steel Matrix Surface Composite
Authors: Xing Zhi Guo , Lu Zhen Lin , Zhou Yong Xin , Liu Jian
Published: August 2009

The erosion wear characteristics of SiC particles reinforced steel matrix surface composite were studied by self-made slurry erosion wear test apparatus with quartz slurries, and contrasted with that of plain carbon steel, high chromium cast iron and low chromium cast iron. The results indicated that the erosion wear rate of the four tested materials has the different changes not only with the quartz particles sizes in slurry, but also with the erosion angle of slurry. The erosion wear rate of SiC particle reinforced steel matrix surface composite is the lowest in four kinds of tested materials under the test conditions. And that of high chromium cast iron is less than that of low chromium cast iron under the same test conditions. The SiC particles embedded the steel matrix could prevent the steel surface from wear brought by quartz particles in slurry erosion wear, and protect the steel matrix, so that the erosion wear resistance of steel matrix could be increased.
Microstructure and Magnetic Properties of Undercooled Fe-80at%Ni Alloys
Authors: Xie Hui , Bai G.H. , Jia L. , Liu E.K. , Lu Zhen Lin
Published: August 2009

Bulk Fe-80at%Ni melts were undercooled by using cyclic superheating and glass slag purification technique, and the maximum undercooling 340 K could be achieved. The microstructures of Fe-80at%Ni alloys were observed by means of optical microscope (OM). The phase composition was identified by X-ray diffraction (XRD) analysis. The magnetic properties of Fe-80at%Ni alloys were measured by vibrating sample magnetometer (VSM) with a DC M-H analyzer. The results showed that there was only single γ-(Fe, Ni) phase existing in undercooled Fe-80at%Ni alloys. Two grain refinements and one grain coarsening were observed in the undercooling range from 28 K to 340 K. The first grain refinement could be ascribed to dendrite-remelting, and the second to recrystallization induced by the stress originating from rapid solidification. The grain coarsening could be considered as a result of solid-state grain coalescence. The measurement of soft magnetic properties showed that the grain size D decreases with an increase of undercooling, the maximum Ms is 109.98emu/g, corresponding to minimum grain size 42.9μm or undercooling 210 K, and the coercive force Hc is in proportion to the reciprocal of grain size D-1.
Synthesis of High Purity Ti3SiC2 Powder by Vacuum Sintering
Authors: Cui Ya Ru , Xu Yun Hua , Xu Shao Chun , Li Xiao Ming , Yang Jun
Published: August 2009

To investigate the possibility and reaction route of fabrication high purity Ti3SiC2 powders using coarse reactants by a relatively simpler method, Ti/Si/TiC mixtures (74μm in average size) added proper amount of aluminum were heated in vacuum sintering furnace with different sintering scheme. The effects of Al addition and temperature on the purity of resultant Ti3SiC2 powder were also examined. The results showed that over 99wt.% content Ti3SiC2 powders could be obtained at optimal temperature 1410°C-1420°C holding 90-120min with 0.10-0.20 Al addition (molar ratio). XRD, SEM and EDS results indicated that Ti5Si3 and TiCx were the main intermediate phases which redounded to synthesize Ti3SiC2 powder subsequently.
Deformation Behavior and Microstructure of Low Carbon High Manganese Steels in Tensile Strain
Authors: Wang Lu Lu , Li Guang Xin , Ma Xin Pei , Jiang Feng , Sun Jun
Published: August 2009

The mechanical properties of two high manganese steels with manganese contents (15% and 25%) were investigated during tensile tests at room temperature. The results indicated that the strengths of steels were a little low and the elongations were improved greatly with increasing the manganese content. Stress fluctuations were found during tensile tests of the Fe-15Mn steels, and as the strain increased the range of stress fluctuations became wider. The strain hardening exponent n of samples changed with strain in a parabola model. The microstructures before and after deformation were investigated and the results showed that phase transformation of γ (fcc) →ε (hcp) and γ (fcc) →ε (hcp) →α (bcc) induced plasticity occurred in the Fe-15Mn steels. However, in the Fe-25Mn steels, at the beginning stage of the deformation, phase transformation induced plasticity played an important role, and with the increase of deformation, the main mechanism was twinning induced plasticity.
Mechanical Property of FRP Bar and Design Method of Hybrid FRP Bar
Authors: Xu Xin Sheng , Zhang Ning , Ji Tao
Published: August 2009

The paper described the detailed design and production method of the FRP bar and the anchorage device, and it also introduced the test method of mechanical properties on the tensile strength, elastic modulus and the rate of elongation of the FRP bar. Moreover, it conducted statistical analysis into test results and put forward the mechanical property index for structural design of the FRP bar concrete. Test results indicated that stress-strain relation of the FRP bar presented linear variation. FRP bar is superior to steel bar concerning high tensile strength-quality ratio and high durability, the elastic modulus and the rate of elongation of the FRP bar are also less than those of the steel bar, it is practicable to use FRP bar as a new type of tensile material in concrete structures. And then, it put forward design ideas of the hybrid FRP bar by a series of analysis on the hybrid effect and the ductility of the hybrid FRP bar.
Resistance to Permanent Deformation and Low-Temperature Cracking of Porous Asphalt Mixture Using the Tafpack Super Additive
Authors: Cao Ting Wei , Wu Shao Peng , Chen Ming Yu , Lin Jun Tao
Published: August 2009

Porous asphalt is one of the most functional structures for the surface layer of asphalt pavement, which has already shown excellent noise reduction property for its 20% air voids in the structure. However, mechanical degradation is also monitored because of the high air voids, for example, permanent deformation in high service temperature and cracking in low service temperature. The Tafpack Super (TPS) additive was used in this study and expected to improve the resistance to permanent deformation and low-temperature cracking of porous asphalt mixture. Unconfined static uniaxial creep test and three-point bending test were conducted to study the effects of TPS additive on the permanent deformation and anti-cracking property of porous asphalt mixture, respectively. Experimental results showed that the TPS additive decreased the creep deformation and increased the creep stiffness modulus in uniaxial creep test. TPS additive had little effect on the brittleness temperature porous asphalt mixtures as shown in three-point bending testing. However, the flexural strength-strain response curve indicated that with the increase of TPS additive, porous asphalt mixtures exhibited better resistance to cracking. Porous asphalt mixtures with TPS additive indicate excellent temperature susceptibility and can be applied to a wider field of road engineering.
Investigation on Preparation and Performance of Micro-Powder Rubber Modified Asphalt
Authors: Liu Cong Hui , Wu Shao Peng , Wang Hong , Zhang Yuan
Published: August 2009

One micro-powder rubber (styrene butadiene rubber-SBR) at three concentration levels are used for manufacturing polymer modified asphalt with a mixing technique. The effects of concentration of modifiers and mixing temperature on the mechanical properties of the compounds are investigated. Based on a limited study, test results indicate that micro-powder rubbers have positive effect on the performance of asphalt in low temperature. Soft point, penetration and ductility show that the ideal percentage of rubber additive (7 wt. %) and preparing temperature (210°C) are brought forward. The fluorescence microscopy test indicates that rubbers are homogeneous dispersed in asphalt and have a little dissolving at the surface of the ultra-fine rubbers. The difference between soft point values in the high temperature storage stability test is only 0.2~0.5°C, which proves that modified asphalts have good storage stability. Complex modulus master curves are drawn to analyze and compare the rheological properties of various modified asphalts. Results indicate that modified asphalt binders have more excellent properties at both high and low temperatures, compared with original asphalt.
Influence of Aging Time on Sigma Phase Precipitation in SAF2507 Super-Duplex Stainless Steel
Authors: Zhang Wei , Zou De Ning , Fan Guang Wei , Li Jiao
Published: August 2009

Specimens of SAF2507 super-duplex stainless steel were heated at 920°C with different aging time. The phase transformation and development of microstructure in the materials were investigated by color optical microscopy, scan electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. The hardness was tested by HB-3000B hardness tester. The facts that sigma phase precipitated right after 2 min. At 920°C, the grain boundaries to be the preferential precipitation sites and the sites changed from ferritic-austenitic phase interface into the inside of ferritic phase was found. Increase in aging time is proportional to the increase in sigma phase precipitation mass was most frequently observed in specimens. For phase precipitation, the values of hardness of the super-duplex stainless steel was enhanced evidently.
Development of an Automated Design System for Oil Pumps with Multiple Profiles (Circle, Ellipse and Involute)
Authors: Kim Chul , Hwang Beom Cheol , Moon Hyun Ki , Lee Hyun Woo , Song Myung Jun
Published: August 2009

An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other other applications. In particular, this type of pump is an essential element of an automotive engine to feed lubricant oil. We perform a theoretical analysis of the internal lobe pump whose main components are rotors. Usually, the outer is characterized by a lobe with elliptical and involute shapes, while the inner rotor profile is determined as the conjugate to the other rotor. Our integrated system, which is composed of three main modules, was developed through AutoLISP using AutoCAD. It generates a new lobe profile, and automatically calculates the flow rate and flow rate irregularity according to the lobe profile generated. Results obtained from the analysis enable the designer and manufacturer of oil pumps to be more efficient.
Influence of the Porosity of C/C on the Characterization of C/C-SiC Composites Prepared by Reactive Melt Infiltration Method
Authors: Wang Ji Ping , Lin Min , Zhang Yong Hui , Xu Zhuo , Jin Zhi Hao
Published: August 2009

C/C-SiC composites were rapidly fabricated using C/C with four different porosities in the range of 12.4%~45.7% and silicon by reactive-melt-infiltrated (RMI) method. The influence of the C/C porosity on the Si infiltration during the processing and on the microstructure and mechanical properties of the resulting C/C-SiC were investigated. The results show that β-SiC was formed by Si/C reaction and free Si remained in the composites. A higher porosity of C/C leads more Si infiltrating to the preform and produces higher density of C/C-SiC with lower porosity. The flexural strength of the composites was strong influenced by the matrix content and the interface between different phases. C/C-SiC derived from C/C with 24.8% porosity has the highest flexural strength (325.1MPa).
Computer Simulation of Fluid Flow, Heat Transfer for the Production of Cu Thin Wire by OCC Process
Authors: Jang Kyung Wook , Lee Jung Il , Lee Joo Ho , Cho Kyoung Won , Choi Good Sun , Lim Jae Won , Yang Gwon Seung
Published: August 2009

In the present study, the fluid flow and the heat transfer with solidification analyses for the Cu thin wire production by OCC (Ohno Continuous Casting) process. The OCC process is widely used to produce cylindrical column castings continuously, a number of researches have been focused on the OCC process. However, few researches on the production of Cu thin wire by the OCC process have been reported, therefore it is necessary to investigate and optimize the process variables of the OCC process when producing the Cu thin wires. A commercial multiphysics software was used to analyse to the flow pattern and the temperature distribution in the OCC system proposed in the present study. Effect of the casting speed, the OCC mold temperature, the melt temperature on the castablility of the thin Cu wire and flow pattern and temperature distribution of the melt were discussed. It is expected that the present study is able to give the design parameters of the OCC system for production of Cu thin wire before the actual OCC system construction.
On Cold Materials of Pavement and High-Temperature Performance of Asphalt Concrete
Authors: Chen Mei Zhu , Wei Wei , Wu Shao Peng
Published: August 2009

With global climate becoming warmer more and more attention is being paid to cold materials. Lower surface temperature contributes to decrease the temperature of the ambient air as heat convection intensity from a cooler surface is lower. Such temperature reductions can have significant impacts on cooling energy consumption in urban areas, a fact of particular importance in hot climate cities. The black surface of asphalt pavement absorbs more heat from the sun, and higher temperature of pavement surface contributes to increase the effect of the urban heat island, but affects the performance and life span of a pavement. Asphalt pavements form an integral part of any transportation system and are typically engineered to last 15 years or more, but many have been failing early due to potholes, cracks, raveling and other problems. Cool pavement are mainly aimed to decrease the effect of asphalt pavement on the urban heat island, but the influence of cold materials on the high-temperature performance of asphalt concrete pavement is paid little attention relatively. In this paper, it’s discussed that the effect of asphalt-pavement high temperature and its improving measures. And the mechanism of cool pavements is introduced, and possible technologies applied to asphalt pavements are reviewed. The idea of asphalt concrete pavement with automatic temperature-control is put forward.
Characterization of Nanocrystalline CoCrFeNiCuAl High-Entropy Alloy Powder Processed by Mechanical Alloying
Authors: Zhang Kui Bao , Fu Zheng Yi , Zhang Jin Yong , Wang Wei Min , Wang Hao , Wang Yu Cheng , Zhang Qing Jie
Published: August 2009

The equiatomic multicomponent CoCrFeNiCuAl high-entropy alloy powder was synthesized by mechanical alloying. The effects of milling time and heat treatment on the structure and morphology of the ball milled alloy were investigated. Single BCC solid solution structure appears when the alloy is ball milled more than 30h. The 60h ball milled alloy powder shows a mean particle size of 3 μm, which is actually hard agglomerations of nanosized crystals with crystalline size less than 10nm. The 60h ball milled alloy exhibits good chemical homogeneity. The single BCC solid solution structure transforms to a BCC and a FCC phases when annealled at 600°C for 1h, which can be attributed to the supersaturatable solid solution formation during the mechanical alloying process.
Application of Al-Mg Alloy in Bearing Steel
Authors: Gong Wei , Jiang Zhou Hua , Zhan Dong Ping
Published: August 2009

There is less study about the effect of magnesium on characteristics of bearing. In the paper, the bearing steel was modified by three types of Al-Mg alloys. Firstly, the total oxygen content value was measured, and then the inclusion size, shape and chemical composition were analyzed by optical microscopy, SEM and EDX. The results show that, after treated by Al-Mg alloy, the total oxygen content descends remarkably and the alumina inclusion with big size and different shapes transform into spinel with small size and spherical shape. The optimal effect of inclusion modification is acquired after treated by NO. 3 Al-Mg alloy containing 16.55 wt% Mg, most of the inclusions in steel are spinel and magnesia, and the size of 96.23 wt% inclusions is less than 3μm.
Sigma Phase Precipitation of Duplex Stainless Steel and its Effect on Corrosion Resistance
Authors: Han Ying , Zou De Ning , Zhang Wei , Huang Rui
Published: August 2009

The present study concerns the influence of aging parameters on the microstructure and corrosion behavior of duplex stainless steel S31803 and S32750. It has been found that the microstructural evolutions were extremely sensitive to sigma phase precipitation during aging treatment, and sigma phase was enhanced with the increase of aging time from 2 min to 120min at its precipitation peak temperature 850 °C for S31803 and 920°C for S32750 steels respectively. The precipitation of sigma phase in S32750 is ahead of that in S31803 steel, within 10min, the sigma phase precipitation rate of S32750 is much faster than that of S31803 steel. The precipitation amount of sigma phases in S32750 steel is noticeable higher than that in S31803 steel during any aging treatment. The corrosion resistance is directly influenced by the abundant sigma phases, especially for the S32750. This result is helpful for practical aging treatment establishment of the S31803 and S32750 duplex stainless steels.
Fast Densification of B4C Ceramics with Al2O3 as a Sintering Aid by Spark Plasma Sintering
Authors: Zhang Fan , Fu Zheng Yi , Zhang Jin Yong , Wang Hao , Wang Wei Min , Wang Yu Cheng , Shi Jing
Published: August 2009

The densification behavior and mechanical properties of B4C by SPS at 1900°C for 2 min with additions of Al2O3 up to 10 wt.% were investigated. When the additional of 10 wt.%, the relative density was 99% and the hardness went to 33GPa. Sinterability was greatly improved by the addition of a small amount of Al2O3, and the SPS technology with high hearing rate is particularly attractive for prepare of poorly sinterable materials. The improvement was attributed to the enhanced mobility of elements through the Al2O3 near the melting temperature. As a result of this improvement in the density, mechanical properties, such as hardness, fracture toughness, increased remarkably.
Fracture Characteristics of Vacuum Diffusion Bonded TA2 Titanium to 1Cr18Ni9Ti Stainless Steel Joint with Nb+Ni Interlayers
Authors: Li Jing Long , Huo Li Peng , Zhang Fu Sheng , Xiong Jiang Tao , Li Wen Ya
Published: August 2009

Pure titanium TA2 and 1Cr18Ni9Ti stainless steel were vacuum diffusion bonded using Nb + Ni foils as interlayers, where Nb foil was adjacent to TA2 and Ni foil adjacent to 1Cr18Ni9Ti. The samples were heated to a temperature of 800°C at a pressure of 10 MPa and kept for 60 min, and then to a temperature of 900°C at a pressure of 1 MPa and kept for 30 min. The mechanical properties of the joint were characterized by the tensile strength test. The average tensile strength of the joints was about 398 MPa. The fracture characteristics of the joint were investigated using scanning electron microscope. The fracture of tensile test samples occurred in the Ni3Nb intermetallic compound formed in the interlayers.
Investigating the Properties of Machinable Ceramics SiC/C(Graphite) Prepared by Plasma Activated Sintering
Authors: Li Hong Wei , Zhang Qin , Jin Zhi Hao , Qiao Guan Jun
Published: August 2009

Machinable SiC/graphite composites were fabricated by Plasma Activated Sintering (PAS), which characterized by high heating rate, short time sintering and high efficiency process. The staring powder mixture included SiC, graphite power and a few sintering aids. They were sintered by PAS under 30 MPa Pressure in vacuum at 1500°C and 1550°C, respectively. The density, bending strength and hardness were measured. The phase and the microstructure of the composites were also investigated. The results indicated that the relative density of SiC/C(graphite) composite sintered at 1550°C was more than 99.5%, the bending strength was 336.6MPa, but surface Vickers hardness was 5.8GPa far lower than SiC ceramics. The machinability of SiC/Graphite sintered by PAS in 1500°C was good because the continuous weak microstructure played a crucial role in the machining process, including a lot of weak interface between the grains of SiC and graphite partials and nearly 20vol% pores in the composite ceramics.
Research on the Hot Precision Processing of TiAl Alloys
Authors: Chen Yu Yong , Chen Yan Fei , Xiao Shu Long , Kong Fan Tao , Tian Jing , Xu Li Juan
Published: August 2009

γ-TiAl components due to their unique properties are on the verge of industrial application for increasing operation temperature and improving energy efficiency, especially in aerospace and automobile areas. This paper describes the recent developments of hot precision processing in ingot metallurgy technology including investment casting, canned forging and sheet rolling of TiAl alloys. Alloys development and the melting technology were discussed. Investment casting of TiAl alloys has been successfully developed to manufacture net-shape components. Research aimed at producing TiAl sheets through canned forging and rolling is introduced.
Preparation of C/C-SiC Brake Materials with Low Cost and High Friction Performance
Authors: Zhang Yong Hui , Xiao Zhi Chao , Yang Jian Feng , Wang Ji Ping , Jin Zhi Hao
Published: August 2009

C/C-SiC brake materials were prepared by improved chemical liquid vaporized infiltration (CLVI) combined with liquid silicon infiltration (LSI) process, which needed less than thirty hours. The microstructure and frictional properties of the material were investigated. The density and porosity of the C/C-SiC brake material were 2.05 g/cm3 and 4.8%, respectively. The average dynamic friction coefficient of the materials was about 0.36, and the friction coefficient was stable. The average linear wear rate was less than 4.7 µm cycle-1 for rotating and stationary disk. The matrix composition and microstructure resulted in the high frictional performances.
Preparation and Mechanical Properties of Carbon Nanotubes Reinforced Barium Aluminosilicate-Silicon Nitride Composites
Authors: Guo Rui , Wang Bo , Gao Ji Qiang , Yang Jian Feng
Published: August 2009

Dense multiwall carbon nanotubes (MWNTs) reinforced barium aluminosilicate (BAS)–silicon nitride (Si3N4) composites were fabricated by hot-pressing sintering. The effect of MWNTs on the microstructure, compositional investigations, as well as mechanical characterization of the composites was investigated. The results show that MWNTs were preserved in the composites after sintering and present good adherence to matrix grains. The incorporation of 3% 1-2μm MWNTs effectively improved the fracture toughness of the BAS/Si3N4 composites from 8.02 to 8.6 MPa•m1/2.
Effect of Precursors on Transmittance and Microstructure of Mullite Ceramics
Authors: Zhang Gui Min , Fu Zheng Yi , Wang Yu Cheng , Wang Hao , Wang Wei Min , Zhang Jin Yong
Published: August 2009

Two different kinds of mullite precursors with composition 3Al2O3•2SiO2 (3:2) were prepared by conventional drying ethanol solution and spray-drying aqueous solution of aluminum nitrate nanohydrate and tetraethoxysilane, respectively. The results of scanning electron microscope (SEM) indicate that one powder consists of irregular particles with size of 1-10μm, the other powder is made of inhomogeneously sized hollow spherical particles with mean size of 0.5-5μm. The TG-DTA curves indicate the hollow spherical particles are unfavorable to eliminate the decomposed products. After the precursors were sintered by Spark Plasma Sintering at 1450°C for 10min, the microstructures of the former are made of fine equiaxed grains with sizes of around 0.5μm, the latter consist of elongated grains distributed in the matrix of fine grains with imhomogenous size of 0.5~10μm due to the liquid phase forming. The different microstructures lead to the former sintered body is transparent, while, the sample from spray-drying is opaque.
Synthesis of Fe3Si-Ti(C0.3, N0.7) Multiphase Composite Ceramic from Iron Tailings and its Properties
Authors: Li Xing Wang , Xu Li Hua , Zhang Xiao Meng , Liu Ming , Hao Hong Shun , Yang Jian Ying
Published: August 2009

The output quantity of iron tailings increases rapidly with the development of metallurgical industry and the growth of the requirement for minerals in the world, which could cause severe hazard to our environment. Therefore, it is very important to recover and reuse these tailings to protect the environment and use natural resources effectively. In this paper, the Fe-Si-Ti multiphase composite ceramic has been synthesized from the Iron ore tailings of Panzhihua region with the carbothermal reduction nitridation (CRN) method. The phases and microstructures of sintered body were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FSEM) and energy dispersive spectroscopy (EDS). The XRD pattern indicates that the main phases of the samples are Fe3Si and Ti(C0.3, N0.7). Meanwhile, FSEM and EDS show that Fe3Si is surrounded by Ti(C0.3, N0.7). Besides, the physical properties of the sample are tested, especially the wear resistance. The test results show that the synthesized Fe3Si-Ti(C0.3, N0.7) composite ceramic has good wear resistant property, high hardness and larger thermal expansion coefficient, which indicates it can be used as the abrasion-proof material or transition layer between the metal and inorganic coating. At last, based on FSEM and EDS, the microstructure and elements of the abraded surface of sample is analyzed.