bluuebunny/crossref_metadata_2025 huggingface dataset:
An Investigation of High Temperature Oxidation Dynamics of U71Mn Steel
Authors: Zhao Zeng Wu , Li Yong Zhi , Li Bao Wei , Wu Wen Fei
Published: December 2011

Oxidation of U71Mn steels under three different reheating curves in air are experimentally analyzed in this study. Total heating time of the heating curves are numerical computed before experiment. The results showed that oxidation began from about 900K, become noticeable and accelerated at near 1100K and became fast from about 1250K. The total mass increase of oxidation under high, typical and low heating rate are 159, 131 and 104 mg/cm2，when the total heating time are 268, 286, and 316 minutes. Keywords: oxidation; steel; high temperature; reheating furnace
Welding Sequence Optimization of TA15 Airplane Wall Panels
Authors: Dong Zhi Bo , Wei Yan Hong , Zheng Wen Jian , Hu Guang Xu , Ma Rui
Published: December 2011

TA15 airplane wall panels are used widely in aircraft manufacture, which consist of some reinforced ribs and a motherboard. Therefore, welding sequences of different reinforced ribs directly determine distortion and residual stress distributions of welding wall panels, and then affect the structure service performance. Therefore, it is important to get the optimistic sequence during manufacture processing of welding wall panels. This paper analyses and predicts regularities of distributions of residual distortion and stress under four kinds of different welding sequence namely, order welding sequence, head-tail welding, head-tail symmetry welding and center symmetry welding. Compared the distortion and residual stress of four kinds of sequences, it is obvious that the welding distortion is smaller and welding quality is better under head-tail symmetry welding sequence, and the order welding sequence is the worst. The simulated distortions are in good agreement with the experiments. So this study puts forward the best welding sequence when welding airplane wall panels, which adapt to any amounts of reinforced ribs welded with the motherboard.
Numerical Study on Magnetic Field Characteristics of Typical Permanent Magnet
Authors: Shi Chang Liang , Zhang Yi Shun , Jiao Hong Guang
Published: December 2011

Selecting a single piece of typical rectangular open planar magnet，with its axial magnetization, to build a finite element model. Based on ANSYS software, the article used NdFeB45 material properties, giving 100×100×10mm to fit the relationship of three-dimensional size. In the air zone as 10 times as model size, it adopted a static simulation analysis of the effect on relationship between axial magnetic distance and magnetic field strength. The magnetic field contours as simulation results, after the Origin software fitting process, obtained an equation is: ; Comparing with the formula: , which reflected the basic characteristics of permanent magnetic field, and with the numerical results by Jing-tian LI using equivalent magnetic charge method, they all appeared: the magnetic field strength exponentially decrease along with the magnetic distance increases, the magnetic field non-uniformity coefficient is of 4.628% deviation, the fitting correlation coefficient R is 0.99924; As a result of the numerical verification results, it also visually response to the magnetic field parameters of open permanent magnet.
Study on Viscosity of Zr-Cu Alloys Based on Viscosity Measurement and Hirai Model
Authors: Wang Jing Song , Huang Shu You , Cao Li Jun , Sun Hao Yan , Wang Jing Hua , Xue Qing Guo
Published: December 2011

In this paper, the viscosity of molten Zr50Cu50 alloy was measured by using NaF-CaF2 covering slag protection combining rotating cylinder method firstly under non-vacuum melting condition. The curve of viscosity and temperature was acquired stably in the temperature range from 1370K to the liquidus temperature (1208K). According the Arrhenius equation form, the viscosity-temperature relation of molten Zr50Cu50 alloy can be fit as the following equation: （1208K50 alloy can be calculated by the above equation in the range of 1370 to 1208K. The viscosity values of molten Zr50Cu50 alloy calculated by Hirai model are relatively small, so the corrected Hirai model was obtained by the measured viscosity data. The viscosities of molten Zr-Cu alloys can be expressed by the following corrected Hirai model: The viscosities of typical molten Zr-Cu alloys were calculated by the above corrected model. The results showed that the viscosities of Zr-Cu alloys are larger at the respective liquidus temperature. The fundamental data were provided for researching the relationship between viscosities of molten Zr-Cu alloys and amorphous form ability.
Geometric Parameters Optimization Design for Aluminum Alloy Welding Joint Based on Increasing Fatigue Strength
Authors: Liu Xue Song , Wang Ping , Yan Zhong Jie , Wang Qiang , Fang Hong Yuan
Published: December 2011

The geometric parameters of the welding joint had an important effect on fatigue strength, so the stress concentration of the typical double sided asymmetric V-notch joint on high speed train was calculated, the relationship between geometric parameters and the stress distribution of the welding joint was analyzed by FEM, also the geometric parameters optimization design of welding joint was proposed. According to theoretical optimization design scheme, the geometric parameters optimization adopted shaping the weld joint by manual TIG welding and processing circle arc on weld toes by milling respectively,. and the fatigue property of the welding joint optimized by different methods was tested. By comparing the experimental results, it was found that manual TIG welding was difficult to obtain the favorable weld toe angle to decrease the stress concentration, and the welding joint was softened obviously. Accordingly, it revealed that the fatigue property was lower than that of initial joint in fatigue testing. On the contrary, the radius of the weld toes circle arc can be controlled accurately by mechanical processing. The stress concentration was reduced obviously by rounding off the weld toe, as a result the fatigue strength of the welding joint could be increased remarkably. Keywords: A7N01, optimization design, geometric parameters of welding joint, FEM
Hot Rolling of FeSi Steels – Effects by Hot Rolling in the Two Phase Region
Authors: Schneider J. , Jungnickel W. , Müller W. , Hermann Harti , Kawalla R.
Published: December 2011

Finish rolling in the two-phase region may offer new possibilities for improving the properties of the FeSi steels with phase transformation. Therefore a deeper understanding of the effects by hot rolling in the two phase region or mixed rolling: multistep hot rolling in the two phase region and in the ferrite region on the evolution of the microstructure is desirable. In this paper we will present the results of our experimental studies on the effect of hot rolling in the intercritical state on the hardening and softening in the ferrite state. It will be demonstrated that depending on the process conditions at hot rolling the austenite ferrite transformation affects the stress strain behaviour in the ferrite state at multistep hot rolling remarkable.
Research on New Thermal Hole Flanging Process of Connection Tube Forming in Heavy Nuclear Power Thick-Wall Head
Authors: An Hong Ping , Liu Jian Sheng
Published: December 2011

The hot hole flanging process of a connection tube in a thick-wall head was researched by finite element analysis and experiment in this paper. The deforming mechanism, main influencing factor and defects in hole flanging were analyzed. According to the stress state and the flow mode of deforming metal, the hole flanging process can be divided into two stages, that is, blending and hole flanging. Processing parameters, such as diameter of pre-holes, space ratio of die cavity, punch shape and size and their effect on forming were researched. The 1:3 scaled experiment was done in 30MN hydraulic press using A508-Ⅲ steel. The formed connection tube had a good quality and its end face was smooth without any crack. The measuring result showed that the error between simulation data and test data was less than 5%, which verified the feasibility of hot hole flanging process and provided an important reference for virtual production. Keywords: Connection Tube Thermal Hole Flanging Thick-wall Head Pro-hole Diameter Space Ratio Scaled Experiment
Parameter Forecast and Parameter Optimization of High Inner-Pressure Hydro-Forming Tees Based on Genetic Algorithms and Back Propagation Algorithms
Authors: Zhang Jian , Li Tan , Chen Xu , Gu Li , Wang Zhi Hua , Cui Hong Xiang
Published: December 2011

In allusion to the non-linear relation in key parameters (internal pressure, axial extrusion force, radial back force) of Three-way tube hydroforming process, forecast and optimization models are established based on genetic algorithms and back propagation algorithms. By using the capacity of non-linear mappings of Artifical Neural Network and the capacity of global optimization of Genetic Algorithms，and using dynaform Finite Element simulation software to get samples and check results, the models can forecast and optimize parameters of T tube hydroforming process. The original tube could be in any bore, length, and wall thickness of a certain range. The results show that by using these models, parameters’ matching test numbers could be reduced, and the quality of T tube is excellent.
Microstructure Analysis of Surface Film on 8407 Die Steel Obtained by Aluminization and Oxidation
Authors: Sun Jian , Wang Xiao Ming , Zou Zong Shu
Published: December 2011

Aiming at improving the anti-melting-loss property of the 8407 die steel, room-temperature hard anodization treatment was carried out for aluminized 8407 steel in order to form an oxide film on the surface. The influences of current density and oxidation time on the thickness and hardness of the film were discussed, and the optimum oxidation condition was obtained. The influence mechanism of oxidation condition on thickness and hardness of the film was analyzed. Furthermore, the sectional microstructure and surface morphology of the film were observed by means of OM and SEM, and the phases in the layer were determined by using XRD. The results show that a uniform, compact and tightly united Fe3O4·Al2O3 film has been obtained on the 8407 steel surface after aluminization and subsequent room-temperature hard anodization treatment. Its thickness is 24~67 μm and hardness is 335~382 HV. The optimum oxidation condition is as follows: current density being around 2.5 A/dm2, oxidation time being around 60 minutes and oxidation temperature being around 25 °C.
Tribological Behaviors of Ti6Al4V with Surface Plasma Molybdenized
Authors: Ben Neng Jun , Liang Wen Ping , Ren Bei Lei , Miao Qiang , Zhang Ping Ze
Published: December 2011

This paper was directed at improving the wear resistance of titanium alloy Ti6Al4V by double-glow plasma surface alloying (DPSA) technology. A molybdenized layer was successfully formed on Ti6Al4V by the DPSA treatments. The microstructure, composition distribution, phase structure and hardness were analyzed by SEM/EDS, XRD and vickers micro-hardness tester. The molybdenized layer was composed of Mo-deposited layer and Mo-diffusing layer. The average surface micro-hardness of the surface modified layer was 1170.8 HV0.1, which was much higher than that of the Ti6Al4V substrate. Tribological characterization was carried out by the ball-on-disc tribometer at room temperature and 500°C. The molybdenized layer significantly reduced the wear rate of the Ti6Al4V alloy, which is only about 6.6% and 4.9% of those of the untreated specimens at room temperature and 500°C, respectively. Due to the good self-lubricating effect of Mo elements at high temperature conditions, the friction coefficient and wear rate of the molybdenized layer were both reduced at 500°C, compared to at room temperature.
Plasma Jet Acquisition and Image Processing Technology
Authors: Zhao Zi Yu , Zhou Guang Tao , Xia Bi Bo , Zhang Su Zhi
Published: December 2011

Experimental system of CCD real-time acquisition is developed according to high temperature property of plasma jet. Mathematical model of gray image and jet temperature distribution is established and basic principles of the CCD collection is analyzed. It realizes acquisition by a common image acquisition card in LabVIEW environment and real-time display of jet. Jet is collected on the computer image processing by using IMAQ Vision, and it intuitive analyzes the shape and temperature distribution according to pseudo-color image processing results of the jet temperature field. Experimental results deepen understanding of the complex nature of plasma jet, which have a guiding significance on the plasma technology in materials processing application.
Physic Simulation of Slurry Preparation by Ultrasonic Vibration in Semisolid Metal Processing
Authors: Zhao Jun Wen , Wu Shu Sen , Dai Guang Ze , Han Jing , Huang Xing Min
Published: December 2011

In current research, a series of visualization experiments simulating the action of ultrasonic vibration (UV) in metal slurry preparation process on fluid flow, grain nucleation and growth as well as its interaction with viscosity of fluids were conducted. In these visualization experiments, the metal slurry maker was substituted by a transparent cup while the liquid and semisolid slurry of metal were replaced by other fluids or mixture system with similar characteristics. Scaled-up UV was applied to the liquid or mixture systems. The simulation shows that UV can roll up the particles at the bottom of the cup and make the liquid convection intense below the radiating surface of sonotrode while weak above it. UV can break dendrites rapidly and distribute them in melt. High viscosity reduces the actual power transmitted into liquid, and higher viscosity requires higher inception power of UV.
Investigation on Nozzle Layout at Secondary Cooling Zone of Round Billet Continuous Casting
Authors: Bi Yan Yan , Chen Deng Fu , Zhang Jian , Wang Shui Gen
Published: December 2011

Nozzle layout has an important role in fulfilling the operational and production requirements. The nozzle arrangements in Ⅱ zone of secondary cooling of a round billet continuous caster in a steel plant are simulated and the water flow density distribution at different range of air pressure and water pressure are analyzed. The result is, the spray zone of two adjacent nozzles which are mutual vertical to each other exist great wrap area，which cannot be eliminated when the air pressure and water pressure are decreased. According to solidification and heat transfer theory, with the steel performance parameter and the accurate boundary conditions, two dimensional heating transfer mathematical model was established, which based on finite difference method and the mind of setting slices on the slab along the casting direction. The surface temperature distribution of round billets in Ⅱ zone of secondary cooling are computed and the temperature curve of different stagger angles of nozzle pairs in consecutive rows are compared. The results show that the temperature at the center of nozzle and spray wrap are all located at the wave trough of surface circumferential temperature curve, the temperature fluctuation of temperature curve that the stagger angle is 22.5° is smaller than when it is 45°. Eliminate the effects of non-uniform surface temperature distribution on the strand quality, thus reducing the defects in the finished product.
Study on the Section Inhomogeneity of VN Microallyed Heavy Plate during Controlled Rolling
Authors: Li Nan
Published: December 2011

The finite element method and physical simulation were used to research the section effect of 50mm heavy plate microalloyed with VN during rolling and the effect of controlled rolling schedule on the section inhomogeneity. We can conclude from the results that when the whole reduction of the plate is constant, the increase of reduction in pass makes for the deformation conveying towards center layer of plate and reducing the section inhomogeneity. To the process that 220mm thick plate blank was rolled to 50mm thick plate, when the rolling pass decreased from 10 to 6, the accumulated deformation of the center layer was increased from 58.35% to 67.87%, and the austenite grain size decreased from 41.3μm to 35.4μm. The effect of final rolling temperature depends on the heat preservation: if there is no heat preservation there almost has no effect on the section homogeneity; if there has a suitable heat preservation, the section inhomogeneity can be reduced efficiently, and the best homogeneity can be obtained when final rolled at 870°C. Key words: heavy plate, VN microalloying, section effect, finite element method
Numerical Simulation of the Stamping Forming Process of Alloy Automobile Panel
Authors: Zhang Jian , Ning Yu Lin , Peng Ben Dong , Wang Zhi Hua , Bi Da Sen
Published: December 2011

6xxx based alloy auto body sheet will be used widely in the future, but, in the recent, one of the difficulty in practice is its poor formability. In this paper properties parameters of 6061 aluminum alloy sheet are investigated by means of examination; By using machine performance parameters of 6061 aluminum alloy, finite element software eta/DYNAFORM of Sheet Forming make the numerical simulation of auto deck lid outer panel .Stress, plastic strain, thick variety are analyzed; and the wrinkling and cracking prone areas identified. Therefore, the effective reference can be provided for design of forming process of 6xxx Based Alloy auto panel.
The Effect of Bell-Type Annealing Temperature on the Mechanical Properties of SPCC Cold-Rolled Steel Sheet
Authors: Wang Zhi Hua , Zhao Yan Ping , Li Yun Tao , Liu Xiang Hua
Published: December 2011

Under laboratory conditions, simulated Bell-type annealing technology , researched the annealing temperature on the SPCC cold-rolled steel sheet mechanical properties. The results indicate that when the time of annealing is shorter (1h), the hardness of steel that used to test decreased with the annealing temperature increased; when the time of annealing is longer (5h), the microhardness is increase slightly with the annealing temperature increased, while the lower plastic decreased.
Field Synergy Analysis for Inclusion Removal in the Continuous Casting Tundish
Authors: Zhang Mei Jie , Lin Xiao Long , Gu Hua Zhi , Zhu Hong Xi , Deng Cheng Ji , Xin Zhan Wu
Published: December 2011

The field synergy principle has been successfully used for optimization design of heat transfer exchanger. In this subject, the field synergy between the molten steel flow field and the inclusion concentration distribution is analyzed based on the mass transfer equations and removal mechanisms of inclusions. Then, inclusions removals of different particle sizes are numerically calculated for a two-strand tundish. The results show the large particle size inclusions are removed mainly by Stokes floatation and the removal efficiency has no obvious relationship on flow field. The small size inclusions removal efficiency is influenced by the synergy between the velocity vectors and the inclusion concentration gradients. So, changing the flow field mainly promotes the removal efficiency of small size inclusions. For the selected two-strand tundish, flow controls should be set for removing those inclusions which particle sizes are less than 100μm,. When the inclusion particle size is less than 10μm, the overall maximum removal efficiency is no more than 25%. So some new metallurgy techniques should be developed to improve the removal efficiency of small size inclusions. Keywords: Continuous tundish; Inclusion removal; Field synergy
Mathematical and Physical Modeling of Soft Cobbing Process of Hot Rolling Steels
Authors: Mazur Igor , Cherkashina Tanya I.
Published: December 2011

The soft cobbing, used in steel’s continuous casting, is widely applying in technologies of rolled metal manufacturing. It is important to know ingot’s stress-strain state and dynamics of ingot’s changes while cobbing, when there is a liquid metal in the centre of section. The complex questions of numerical modeling of soft cobbing process and experimental investigation on physics plasticine models are considered in presented work. The analysis of findings is presented in the article.
Research and Analysis of Material Flow Regularity in the Process of Cross Wedge Rolling for Wrought Aluminum Alloy
Authors: Zhao Pei Feng , Han Cun Cang , Zhang Yan Min , Song Ke Xing
Published: December 2011

With widely use of aluminum alloy in the cares and other industry fields and the like, the aluminum alloy workpieces are becoming the important components, such as load bearing and so on, in which it has been gradually paid attention to the formation and the producing roughcast of shaft forging part of aluminum alloy. the process of across wedge rolling for wrought aluminum alloy has gradually taken notice of improving production rate and saving metal in this field because of its advantages and superiorities. It is very necessary to research and analyze the flow regularity and forming characteristic of aluminum alloy. In this paper, the forming process of cross wedge rolling for wrought aluminum alloy is simulated with Deform 6.0 soft. Thus, it is analyzed that features about cross wedge rolling for aluminum alloy and changeable characteristic of stress in the central axis and changeable regular of effective stress in wedging stage and stretching stage . At the same time, it is researched that the flow characteristic of aluminum alloy from outer layer to central axis. The results as following: in the forming process of cross wedge rolling for aluminum alloy, the central portion of workpiece is applied by two pairs of tensile stress and one pair of compression stress. The flowing velocity of aluminum alloy is gradually reducing from outer layer to center portion along workpiece’s axis. Keywords: Cross Wedge Rolling, Wrought Aluminum alloy, Stress, Numerical simulation
Flow Behavior of Ultra-High Strength Boron Steel at Elevated Temperature
Authors: Bao Jun , Liu Hong Sheng , Xing Zhong Wen , Song Bao Yu , Yang Yu Ying
Published: December 2011

Ultra-high strength boron steel is widely used in a new hot stamping technology which is hot formed and die quenched simultaneously in order to obtain stamping parts with 1500MPa tensile strength or higher. Tensile experiments were carried out with ultra-high strength boron steel in a range of temperature 500°C~860°Cand strain rate 0.01/s~1/s with the thermal simulation testing machine Gleeble 3800, and the stress-strain curves were obtained. The influences of the deformation temperature and strain rate on the stress-strain curves were analyzed. The results show that hot behavior at elevated temperature of ultra-high strength boron steel consists of strain hardening and dynamic recovery mechanism, which can be accurately described by the mathematic model. Keywords: Ultra-high strength boron steel, hot stamping, hot flow behavior
Simulated Research on Hot Forming Mechanism of Sour Service Drill Pipe Steel
Authors: Hu Mei Juan , Wang Peng , Han Li Hong , Han Xin Li
Published: December 2011

The dynamic mechanical behaviors of as-cast sour service drill pipe steel under development during hot deformation were studied in this paper by using Gleeble-3500 thermal mechanical simulator. The compressions were carried out at the temperature of 900°C, 1000°C, 1100°C, 1200°C and strain rates of 10s-1, 1s-1and 0.1s-1. The compress degree was about 70%, and then the maximum true strain for each specimen was 1.2. The experimental results show that the peak stress was related to the compression temperatures and the strain rates. Through respectively analyzing and studying the true stress-true strain curves, the hot deformation constitutive equation and the deformation activation energy were obtained by regression analysis. The evolution of microstructures at various strain rates and temperatures was discussed. Experimental results can provide scientific basis for analyzing the hot deformation processes and controlling quality. Keywords: sour service drill pipe, hot compression, true stress-true strain, constitutive equation, microstructure
Calculation Model of Punch Force during Tube Extrusion
Authors: Wang Zhong Tang , Qi Guang Xia , Wang Fang , Zhang Shi Hong
Published: December 2011

] Theoretical calculation formula of punch force during tube extrusion has been proposed by means of slab method. On the basis of theoretical and experimental study, it is found that theoretical results of extrusion force given by the calculating formula approached to that of the experiment, and the relative errors are less than 20％. It is also found that the extrusion force is closely related to deformation temperature, lubricant and the ratio of extrusion. The calculating formula of extrusion force is given by considering the factors which are the conical angle of die, and the friction coefficient between the deformation zone and the extrusion container, and the friction coefficient between the undeformed zone and the mandrel. Key Words: Tube, Extrusion, Force, Physical model
Experimental Analysis of Seed Effect on the Directional Solidification of Sn-Pb Alloy
Authors: Chao Long Sun , Chen Yu Ru , Wang Fang Chun
Published: December 2011

In this paper, an experiment model for the directional solidification of Lead/Tin alloy is built and the effects of different-shape seeds on the microstructures on the solidification microstructure are investigated. In a casting process, the temperature and concentration fields will affect the microstructures of materials and this influence is the key point of improving their mechanical and physical properties. It is not easy to control the morphology of solidifying microstructures. The scheme of directional solidification can make the microstructures grow along a fixed direction and it is also the base of single-crystal growth. In the experiment, a poly-grain seed with the same initial concentration of the solidifying casting is used to induce the columnar growth at the bottom portion of the casting, which could avoid the equiaxed growth due to the high undercooling or cooling rate there. In the experimental analysis, we studied the influences of different geometry seeds on the constrained growth, the preferential growth direction of dendrite, the grain size, the temperature gradient, the growth rate, the primary arm spacing and the secondary arm spacing. From the microstructure observation, the adding seed casting reduced the chill-affected and extended the directional solidification zone. This is expected to have the better or more complete structure of directional solidification. Keywords: Directional Solidification, Seed, Heat Transfer and Microstructure
Numerical Calculations on the Grating-Assisted Phase Matching Condition of High Harmonic Generation in Photonic Crystal Fiber
Authors: Ren Hai Zhen , Zhang Ming , Guo Peng , Yang Lin Feng
Published: December 2011

We numerically investigated the grating-assisted phase matching (GAPM) of high harmonic generation (HHG) from the interaction of intense femtosecond laser pulse and rare gas in hollow core photonic crystal fiber (HCPCF). Our results show that the GAPM of HHG in HCPCF is especially suitable for photon energies in the range of 100~1keV. The calculated modulation period for GAPM of HHG in HCPCF is on the order of micrometer or sub-micrometer. This makes it easy to implement the GAPM of HHG with a counter-propagating modulation laser light in HCPCF. The high harmonic conversion efficiency is expected to be dramatically improved for the longer interaction length provided by the very low loss of HCPCF.
Casting Process Optimization for Large Bearing Bush of Zinc-Base Alloy
Authors: Gao Cun Zhen , Yang Di Xin , Xie Jing Pei , Wang Ai Qin , Wang Wen Yan
Published: December 2011

The numerical simulation of temperature gradient in the solidification process for large bushing castings of zinc-base alloy was made with HUAZHU CAE/Inte-CAST10.0 software in this paper. Tendency and the position of shrinkage were predicted,and the effect of cooling water rate and cooling time on temperature gradient and shrinkage during the molten metal solidification was discussed. The results show that:seting chilled iron at bottom of bearing bush and using water-cooling metal core in inner cavity of casting simultaneously, can eliminated shrinkage hole and porosity.
Detonating Gas Simulation Experiment System Based on the Dynamic ESD Model on Human Body
Authors: Dong Xiu Jie , Chen Xu , Zhang Jing Chang , Zhang Liang
Published: December 2011

Variation of dynamic electrostatic discharge (ESD) on human body that miners’ voltage,capacitance and resistance varies with the body’s dynamic change in coal mine environment is studied. A circuit model of the body’s dynamic ESD in coal mine environment is constructed. The simulation experiment system of the gas detonation by the human body ESD in coal mine is developed successfully. System principle, system hardware design and system software design is expounded. Simulation experiments with different body’s ESD model and the discharge gap has been done. Experimental results show that the system can be carried out series of experiments of the human body ESD model detonating mixed gas, it is concluded that the gas concentration that is the easiest to be detonated is about 8.7%. but not the higher gas concentration is , the more explosive is. The results provide an theoretical and experimental evidence for the safe electrostatic production and management in coal mine Keywords:simulation experiment system; dynamic ESD model ; hardware and software design ; human body capacitance
The Significant Difference with the Relationships of T2 and Moisture Distribution between Untreated and Esterified Poplar
Authors: Wang Xiang Jun , Zhang Ming Hui , Wang Xi Ming
Published: December 2011

the moisture distribution in untreated and esterified poplar with Maleic anhydride was studied in the present paper employed nuclear magnetic resonance (NMR). The results show that relaxation times decrease with the the fall of moisture content, and there is a linear equation between the moisture content and transverse relaxation time in esterified wood. The content of bonding water and free water in the esterified wood decreased simultaneously during the drying.
Vacuum Paddle Fast Pyrolysis Reactor Design and Internal Heat Transfer Investigation
Authors: Li Rui , Deng Xu Sheng , Gou Jin Sheng , Lv Zhao Lin
Published: December 2011

Fast pyrolysis is cracking process in which macromolecule of biomass is broken into small molecular under moderate temperature and at high heating speed. Bio-oil produced by the process can be used as potential alternatives of diesel oil and other chemicals. By investigate different kinds of reactor, a new type reactor called vacuum paddle fast pryoysis reactor is developed with low manufacture cost and operating fee and more stable performance. Two stage condensing system composed of 1st quench stage and 2nd cooling heat exchanger is designed, which is proven effective in avoiding secondary cracking of biomass oil and eliminating block of equipment by tar. At same time, a model describing heat transfer in new reactor is established and solved by unsteady heat conduction equation, which give conclusion on minimum agitating speed and therefore, provide basic theoretical foundation. Keywords: fast pyrolysis, vacuum paddle reactor, condenser, heat transfer
Ultrasonic Treatment of Activated Carbon Used in Adsorption of Basic Fuchsin
Authors: Hao Yi Nan , Wang Xi Ming , Ding Li Jun , Ma Da Yan
Published: December 2011

Xanthoceras Sorbifolia Bunge hull activated carbon (XSBHAC) developed by phosphoric acid activation for removing basic fuchsin (BF) has been investigated. Experiments were carried out as function of contact time, pH (4-10) and temperature (303,313 and 323K). Adsorption isotherms were modeled with the Langmuir and Freundlich isotherms. The data fitted well with the Langmuir isotherm. The Langmuir monolayer saturation capacities of BF adsorbed onto activated carbon were 351.35, 354.96 and 355.94 mg/g at 303,313, and 323 K, respectively.The kinetic models were also studied .The rates of adsorption were found to conform to the pseudo-second-order kinetics with good correlation.Using the equilibrium concentration contents obtained at different temperatures, various thermodynamic parameters,such as △G,△H and △S, have been calculated. The thermodynamics parameters of system indicated spontaneous and endothermic process. Key words: Xanthoceras sorbifolia bunge hull;biosorption; basic fuchsin
Unsteady Conjugate Numerical Simulation of the Solar Chimney Power Plant System with Vertical Heat Collector
Authors: Zhou Yan , Liu Xiao Hui , Li Qing Ling
Published: December 2011

A new kind of solar chimney power plant system combining chimney and heat collector was designed. Paraffin was chosen as the material of energy storage layer and the unsteady conjugate numerical simulation of the system was done by Fluent software. The operation condition of the system was simulated when the solar radiation value was changed with time according to the actual situation. Simulation results showed that: with the increase of solar radiation, flow velocity of the air and the maximum output power increased. At twelve o'clock, the air velocity could reach 1.24 m/s and output power was 122W. Due to the energy storage effect of phase change materials, the system had output power of 1.3W at night. Moreover because of the continuous work of the heat storage layer, in the same condition of solar radiation, the air velocity and maximum output power increased with the system operation days extended.
Research and Application of Pre-Bent Automatic Control Models of 100 Meters Rail
Authors: Bao Xi Rong , Liu Yu Yan , Li Ge , Chen Lin , Wang Jian Guo , Wu Zhang Zhong , Tian Zhong Liang
Published: December 2011

Repeated bending occurs toward the direction of rail head and rail base during the cooling which can lead to significant bending deformation and residual stress after cooling, the longer the rail, the more obvious this phenomenon is. In addition to cooling function, a kind of cooling bed with a pre-bent process will be used in order to solve this problem on 100 meters rail. The synchronous movements on this cooling bed can be realized by the automatic control system after establishing the mathematical model of bending deformation after rolling. The rail is reversely bent toward the rail base before cooling according to the pre-bent control of the pre-bent curve and is straight after cooling which can realize the control of the residual stress after pre-bent and straightening. The straightening residual stress significantly reduced after the pre-bent. Fund: National Natural Science Foundation funded projects （50765004）
Al2O3-TiC/Fe Functionally Gradient Material Prepared by SHS Casting
Authors: Zang Wan Hong , Yuan Chang Lun , Li Yan
Published: December 2011

Al2O3-TiC particles reinforced iron matrix functionally gradient material is successfully fabricated by combining the methods of self-propagating high-temperature synthesis (SHS) with casting. The SHS products are analyzed by SEM and XRD and EDS. The results show that the grain size of the particle is round 1μm~3μm, the composition of the Al2O3-TiC/ Fe surface composite takes on a gradient distribution from outside to inside, and transforms gradually to the matrix metal. The hardness below 0.5mm from exterior surface of the functionally gradient materials increases dramatically and gradually changes to the hardness of the matrix. Key words: In situ generation; SHS; Casting; Surface composite material; FGM
Modelling of Microstructure Evolution during Thermal Processes – A Hybrid Deterministic-Probabilistic Approach
Authors: Hadi Iraj , Jabbareh Mohammad Amin , Nikbakht Roghayeh , Assadi Hamid
Published: December 2011

The present contribution focuses on a recently developed model of microstructure evolution. The model is based on a phase field approach, which takes account of kinetic effects in solidification of alloys and intermetallic compounds. It further incorporates crystal orientation as an additional field variable, which evolves through a Monte-Carlo algorithm. Combination of the phase field approach with Monte-Carlo algorithm allows for physically meaningful and computationally effective simulation of microstructure in polycrystalline and intermetallic forming systems. The paper includes various examples of simulated microstructures in different thermal processes.
Microstructure and Performance of Fe-Based Composite Clad Layer Fabricateded by Submerged-Arc Welding Added Alloy Powder
Authors: Wang Li Mei , Liu Jun Bo , Yuan Chi
Published: December 2011

TiC particle reinforced Fe-based composite clad layer were in situ synthesized on surface of Q235 steel by Submerged arc Welding of the mixed powder of ferrotitanium, iron, chromium, nickel and colloidal graphite, etc. Microstructure of the clad layer were observed by scanning electron microscope （SEM） and Energy Disperse Spectroscopy (EDS). Wear resistance of the clad layer was tested on wear tester at room temperature compared with the base material Q235 steel. Microhardness of the clad layer was measured by microhardness tester. Results indicated that the fine TiC particles were formed by Submerged-arc Welding process, and the the TiC particles were dispersed in the matrix. The size of TiC particles was less than 2 μm. The microstructure of cladding layer consisted of TiC particles, martensite and austenite. The average microhardness of clad layer was HV0.2601, which was about 3 times as high as the based metal Q235. On the conditions of same wear and room temperature, the weight loss of the base material Q235 is 10-15 times as much as the composite clad layer. The weight loss increase of the clad layer has a little change with the increase of load and the change of load is not sensitive to the weight loss of the clad layer. The clad layer has good load characteristics.
Effect of Thermocycling on the Thermal Degradation Kinetics of Goatskin Collagen Matrices
Authors: Zheng Xue Jing , Liu Jie , Wang Kun , Tang Ke Yong
Published: December 2011

In the present study, the goatskin collagen matrices were tanned by chrome powder and chestnut extract. The samples were then thermocycled in a container at different temperature ranges with a dwell time of 5 h for different cycles. The thermal degradation behaviors of the collagen matrices before and after the thermocycling were investigated. The Coates-Redfern Method was applied to study the thermal degradation kinetics of different samples. The results indicate that the thermocycling exerted more dramatic effect on the native collagen matrices than on tanned samples. The tanning process endows the samples with extra crosslinking structure, and therefore, less sensitivity to thermocycling treatment. It was found that the thermal treatment at moderate temperature (0~50˚̓˹˰̵̵̵̴͈͂̈́˰̵̼̹̼̈́̈́˰̶̵̵̹̼̳̾̾ͅ˰̿̾˰̸̵̈́˰̸̵̱̼̈́͂̽˰̴̵̷̴̱̱̹͂̈́̿̾˰̱̳̹̱̹̈́͆̈́̿̾˰̵̵̷̵̹̾͂̓˰˸ΔE) of the sample. However, for the samples thermocycled at high upper limit temperature (0~150˚̓˹˼˰ΔE was decreased significantly.
Grain Boundary Character Distribution and its Effect on Corrosion Resistance of Copper and Brass
Authors: Guo Hong , Chen Zhi Wei , Jiang Ying , Cai Zheng Xu
Published: December 2011

The grain boundary character distribution (GBCD) and its effect on the corrosion resistance of copper and brass (H65, H80) after solid solution and cold-rolled annealing were investigated by means of static weight loss method, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and Electron back-scattered diffraction (EBSD).The possible mechanism of the effect of proportion of low ∑ coincidence site lattice (ΣCSL) on corrosion resistance were discussed preliminary. The results show that the proportion of low ΣCSL of the three kinds of samples after cold rolling and annealing all increase obviously compared with samples in solid solution. The proportions of low ΣCSL( such as Σ3,Σ9 and Σ27 ) of H65 brass,H80 brass and copper increase in turn in the same heat treatment conditions. In addition, it can increase the grain boundary ratio of low ΣCSL up to 67.9% by cold rolling of 6% and annealing at 650°C for 10min; The corrosion experiments show that corrosion resistances of samples after heat treatment are much better than that in solid solution. In the three samples, the corrosion resistance of copper is the best and that of H80 brass is better than that of H65 brass. Key words: copper; brass; GBCD; corrosion resistance
Effection of Process Factors Pillaring Agent Prepared on Properties of Pillared-Montmorillonite
Authors: Lv Xiu Ling
Published: December 2011

The paper regard pillaring agent which is the most important research content of pillared-montmorillonite as subject investigated. By changing the pH value of solution to form different pillaring agent which is used to prepare pillared-montmorillonite. Adsorption capacity of pillared-montmorillonite on SO42-ion as standards, the effection of main process factors—pH value during the preparation of the pillaring agent on adsorption capacity of pillared-montmorillonite is explored.
Numerical Simulation of Interfacial Debonding Crack in Particle Reinforced Composites
Authors: Guo Xian Zhang , Zhang Juan Xia , Liang Zheng Zhao , Zhang Ya Fang
Published: December 2011

A numerical test code is used to study the matrix-inclusion interfacial debonding for particulate reinforced composites. In our numerical model, It is assumed to be a three-phase composite composed of matrix, particulate and the interfaces between them. The finite element program is employed as the basic stress analysis tool when the elastic damage mechanics is used to describe the constitutive law of meso-level element and the maximum tensile strain criterion and Mohr-Coulomb criterion are utilized as damage threshold. A single inclusion of gradually interfacial debonding and a complex structure with 20 inclusions of the interfacial damage were studied under plane stress conditions. Results of stress distribution and interface debonding type obtained by numerical method agree well with the MARK and ABAQUS. The influence of heterogeneity of the matrix materials on the resulting process and the stress distribution of the failure process are also studied in the paper. It is found that the numerical test code can help to understand the failure mechanism of the model and it is an effective way to investigate the interfacial damage of composite materials. Keywords: Numerical test, interface, particulate reinforced composite, crack
Digital Image-Based Model for Concrete Fracturing Process Analysis
Authors: Yu Qing Lei , Yang Tian Hong , Zhu Wan Cheng , Zheng Chao
Published: December 2011

Concrete is a heterogeneous composite material. The heterogeneity consists of the distribution and shape of aggregate, interfacial transition zone (ITZ) and the inhomogeneity of each component materials. The key in numerical models for simulating the fracture behaviors is how to describe the heterogeneity actually. In this paper, at meso-scale level general-purposed digital image processing technologies are utilized to characterize the heterogeneity resulting from the shape and distribution of aggregates and ITZ, and at micro-scale level, a statistical method (e.g. Weibull distribution) is used to describe the heterogeneity of each phase. And then a multi-scale numerical model based on digital image is proposed to simulate fracturing process of concrete under loading condition. The proposed model can take the actual distribution and shape of aggregate into account. The fracturing process of concrete in uniaxial compressive tests is simulated by using the model. The results show that the shape of aggregates plays an important role in stress distributions to influence the damage evolution during loading. The proposed model is capable of capturing the complete failure process of concrete materials that includes the initiation, propagation and coalescence of microcracks as well as cracking pattern associated with different loading stages, which is a new tool to study the fracturing behaviors of concrete in more detail. Key words: digital image; heterogeneity characterization; fracturing process; concrete
Prevalence and associated risk factors of Kola nut chewing among secondary school students in Osogbo, Nigeria
Authors: Erinfolami Adebayo , Eegunranti Adekunle , Ogunsemi Olawale , Oguntuase Akin , Akinbode Abiola , Erinfolami Gloria
Published: December 2011

The objectives of this study were to determine the prevalence and pattern of Kola nut use among secondary school students in Osogbo, Osun State, Nigeria. The study also aimed to determine the association of socio-demographic variables (of the students and their parents) with kola nut chewing. A questionnaire consisting of socio-demographic variables, the stimulant use section of the WHO Students Drug Use Questionnaire was administered on three hundred and eighty-five (385) randomly selected students of the two Local Government Areas of Osogbo. The prevalence rate of kola nut use was calculated and some socio demographic variables were determined. The 30-day prevalence rate of kola nut use was 11.2%. The one-year prevalence of kola nut use was 29.1 percent and the lifetime rate was 74.8 percent. Majority of users started at age 14 years or below. Kola nut use was associated with lower age group, poor school attendance, polygamous background, low education of mother, high education of father and the description of mother as being too permissive. The findings suggest the need to increase the awareness of the dangers of kolanut use among adolescents. Control program are urgently needed to prevent student wastage.
Working-aged population's mental symptoms and the use of the Internet
Authors: Korpinen Leena , Pääkkönen Rauno
Published: December 2011

The aim was to study how the working-age population's mental symptoms had a relation to the using of the Internet. In addition, the aim was to analyze how the mental symptoms had a relation to background information. The study was carried out as a cross-sectional study by posting a questionnaire to 15,000 working-age (18-65) Finns. Mental symptoms of responses (6121) were analysed using the model factors age, gender and use of the Internet. Only 0.06% mentioned that they were somehow addicted to the Internet. Based on statistical analyses, age and marital status had an influence on many mental symptoms. The use of the Internet at leisure had an influence on substance addiction and fear situations. The importance of the Internet only had an influence on the fear situations. In the future it will be essential to take into account that the use of the internet can affect mental symptoms.