Papers by Keyword: Experimental Study

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Authors: Yuan Li, Lei Jia, Xu Li Liang
Abstract: In this paper, the role of fly ash and slag powder on the concrete are introduced. Through the experiments that mixing up fly ash , slag powder or two kinds of mineral admixtures in the concrete, the characteristics of property of concrete at different times are learned. The results show that the property of concrete are better when two kinds of mixtures are used than mixing one of them, and the most appropriate proportion of mixing is 30%~40%.
Authors: F. Ayari, E. Bayraktar, J.P. Chevalier
Abstract: The recently developed indentation techniques are awfully advantageous as they are performing in determination of hardness and local elasticity modulus for particular conditions; also they are being able to deal with small sample sizes. This technique is well used to characterize mechanical properties as hardness, elasticity and creep for coating thin layers. Experimental comparison of common nano and micro scales for hardness evaluation has been performed on metal samples and discussed in details in the literature review [1-3]. In fact, it was well detailed that instrumented indentation was found advantageous in both repeatability and a number of measured parameters over classical hardness methods for different materials. As far as thin materials are being very used in various industrial fields, the mechanical characterization moves to micro level scale, with micro-indentation tests of thin films and from Newton -to- micro Newton for loading conditions. A big step forward has been reached for load-depth monitoring during loading and unloading in indentation cycle. Nowadays, hardness and Young’s modulus can be easily defined using Oliver-Pharr [4-5] equations based on a micro scratch test of a very thin film. In this paper an experimental study is conducted and has been validated with a numerical FE model based on a micro indentation test of a metal matrix composite material 110A, used in aeronautic applications.
Authors: Yuan Fa Ding, Wen Guo Huo, Xiang Dong Su, Lan Zhang
Abstract: A new self-lubrication concept based on the techniques including of dry grinding and solid lubricating was proposed for green grinding process. And a kind of self-lubrication grinding wheel was designed with solid powder lubricant and centrifugal impeller inside. The self-lubricating was achieved by the blow out of the solid powder lubricant from the inner cavity of the wheel by the centrifugal force to the grinding surface. The experiments were conducted to study the friction and wear properties of the new cylindrical wheel samples manufactured by the proposed concept. The results showed that the flow channel diameters of 1 to 1.5 mm are the best for the blowing out of the solid lubricant to realize the continuous lubricating. After grinding, the surface coating is even, and the sizes of the abrasive particles are relatively uniform with no peeling into blocks. Although there is a certain wear loss of the grinding surface, the wear rate of the particles on the sample wheels is less than that of the traditional grinding wheel. The computational simulation of the self-lubrication wheel is conducted with the RSM method with FLUENT software to analyze the flow field in the wheel cavity of solid lubricant inside, which is meaningful for the study of the motion of the solid lubricant and useful for optimum design of the wheel design to realize the best self-lubricating performance.
Authors: Jun Cheng, Ya Dong Gong, Yue Ming Liu
Abstract: This paper presents a micro-grinding experiment on AISI 1020 steel to study micro grinding principle. A novel micro shaft grinding tool is fabricated by cold sprayed with CBN grains, the manufacturing is carried out on a desktop micro machine developed by NEU. Influences caused by particle size on surface quality has been discussed, it has been tested that low surface roughness could be achieved on 3000 particle size of micro shaft grinding tool, the roughness of AISI 1020 steel accomplished in the experiment is about 0.086 μm.
Authors: Jin Sheng Wang, Da Jian Zhao, Ya Dong Gong
Abstract: A micromilling experimental study on AISI 4340 steel is conducted to understand the micromilling principle deeply. The experimental results, especially on the surface roughness and cutting force, are discussed in detail. It has been found the minimum chip thickness influences the surface roughness and cutting force greatly. Meanwhile, the material elastic recover induces the increase of the axial micromilling force. The average cutting force and its spectrum analysis validate the minimum chip thickness approximation of AISI 4340 is about 0.35μm.
Authors: Hui Xia, Guo Qiang Liu, Wen Jing He
Abstract: Imaging logging is a new technique which has been developing in recent years, its’ silo facilities could collect large information with high resolution, and the measurement result is usually presented in graphics after processed. This paper presents a new imaging logging technique based on magnetic-acoustic Tomography with Magnetic Induction(MAT-MI), introduces its’ logging principle, gives detailed experimental system, makes a simple copper coil experiment and verifies the feasibility of the technique. These studies will lay a foundation for practical application of new imaging logging technology.
Authors: Yu Run Li, Yan Liang, Xing Wei, Yun Long Wang
Abstract: Lateral dynamic response of pile foundation in liquefiable soil has been one of the focal problems of the geotechnical engineering field and varieties of test methods are put forward by experts and scholars. In the dissertation, a shaking table test is based on and a new calculation method is involved too. It’s the first time that using Fiber Prague Grating (FBG) technology in the method of study on lateral dynamic response of pile foundation in liquefiable soil. Experimental results indicate that calculation by method of FBG is more accurate than that by acceleration integral method. Data processing shows that p-y curve of pile foundation in liquefiable soil can be better to indicate the actual dynamic constitutive relation, and it establishes the theoretical basis of experimental study and engineer application of pile foundation in liquefiable soil
Authors: Xiu Xing Zhu, Shi Feng Xue, Xing Hua Tong
Abstract: During the production of thermal horizontal well, recovery ratio will be reduced by the deficiency of traditional steam injection methods, which include finite effective heating range, poor level of producing reserves etc. In order to improve efficiency of steam and well yield,a new method—multipoint steam injection technology is presented in this paper, which can improve steam injection profile distribution in thermal horizontal wells. Several factors including multiphase flow, pressure drop, variable mass flow and reservoir heterogeneity, are taken into consideration in this method. By the new technology, Steam injection string used in horizontal wells is divided into several independent units through applying matching equipments. Based on the optimization of steam absorption capacity of every unit, steam injection profile distribution is improved. The validation of multipoint steam injection technology and matching equipments are verified through ground simulation tests in this paper. Moreover, the influence of steam injection parameters is also analyzed.
Authors: Azizul bin Mohamad
Abstract: This paper evaluate previous experimental studies on sub-freezing start up of proton exchange membrane (PEM) fuel cell system, and identify issues for further investigation. In a successful cold start, product water from electrochemical reaction in the cathode must be removed from the cell before it turns into ice and causing voltage drop and shutdown also leads to permanent damage to fuel cell components. Successful single PEM fuel cell start up was achieved from temperature as low as-30°C. Some researchers found that cold start of a 30 W stack from-20°C was possible only with aid of external energy. Successful self-start up a 2 kW stack from temperature-5°C was reported but the time taken was unacceptably long and attempts to start up the stack at lower temperatures were failed. Based on the current state of research, further research is necessary to fully understand the operation and mechanism of PEM fuel cell cold start.
Authors: Jiang Lu
Abstract: In this paper, the author investigated the research on coalbed methane and water two phase flow, from microscale to macroscale and field engineering studies. The literature research shown that the microflow in pore scale should pay more attention, especially the mechanism of interaction between gas and water, interaction between fluid flow, adsorption, deformation and even thermal field.
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