Advanced Materials Research Vols. 268-270

Abstract: This paper presents the results of an experimental and statistical study on the effect of high temperatures on the retained mechanical properties of high-strength concretes (HSC). The mechanical properties of HSC significantly change during and later than exposure to elevated temperature. The compressive and splitting tensile strength of more than 400 HSC cylindrical specimens with sixteen mix proportion have investigated to study the effect of mix proportion on the retained mechanical properties of HSC specimens after heating. According to these results, a considerable loss was observed for all mixes and specimens in strength particularly in tensile splitting strength. In addition, these experimental data were investigated using Taguchi approach to find the effective parameters of mix proportion. Also, the most optimum mix proportion was found and checked experimentally. According to our results, by controlling some factors in the mix proportion, it is possible to reduce the retained destructive effects of elevated temperature on HSC specimens.

Abstract: Based on strength and ductility, the seismic capabilities of the chords of arch ribs, web members, horizontal integrations, suspenders and beams of suspenders of concrete filled steel tube (CFST) arch bridges are studied, then the seismic capability of the bridge is obtained. Firstly, the internal forces of the members are calculated respectively by finite element under the actions of gravity representative value and small earthquakes (0.05g). Then the ultimate bearing capacities, the ratio of ductility and the reduction coefficients of earthquake are obtained according to the failure modes. Finally, yield accelerations of ground movement are multiplied by the reduction coefficients of earthquake, which the resistance seismic capabilities of the members Ac are obtained. The seismic capability of bridge is the minimum Ac. Taking Nanning Yonghe Bridge that is a 346m CFST arch bridge as example, the seismic capability is evaluated that the bridge can resisted the earthquake which the acceleration of ground movement is respectively 0.677g. The results show that the method of seismic capability evaluation is a feasible and efficient method for seismic capability evaluation of CFST arch bridge.

Abstract: Analysis of characteristics of mineral resources industrial development in Tarim River Basin, and taking the Bayingolin Mongol Autonomous Prefecture for example, from the contribution of the total amount and economic growth of mineral resources development, industrial development potential, the scale of employment, investment of fixed asset and resources tax analysis effect of economic of mineral resource development in Tarim River Basin. It find that economic effects of mineral resource development is also not fully played important role, in particular, the development potential of mineral resources industry declined, so the future mineral resources should be comprehensive and effective used, strengthening the deep processing of products and further extend the industrial chain.

Abstract: The Fe-Cu-MoS₂ composites with different adding amount of MoS₂ as lubricant were prepared by induction sintering method. Their mechanical and tribological properties from room temperature (RT) to 800°C were tested by universal testing machine and high temperature tribometer. The effects of amounts of MoS₂, temperature, load and sliding distance on the friction and wear properties of composite were discussed. The structure of the composite was analyzed by XRD and worm surface morphologies were observed by SEM. It was found that MoS₂ was decomposed during the hot-press sintering process. Meanwhile, solid solution alloy of Mo and Fe, and sulfides were formed in composite, which were responsible for low-friction and high wear-resistance at elevated temperature, respectively. Hardness and anti-compress strength can be improved by adding 8 wt. % MoS₂. The friction coefficients and wear rates of composites decrease with the increase of adding amount of MoS₂ until a critical value of 8 wt. %. The composite with 8 wt. % MoS₂ shows the optimum tribological properties over the temperature range of RT~800°C.

Abstract: The oil gathering and transportation process is a key link in the oil industry. In this paper, to reengineer the ground works process of an oil production plant as an example of business process reengineering, the simulations of the oil and gas gathering and transportation process before and after the business process reengineering are conducted by using of SIMPROCESS software. While the utilization rate of various devices is compared with process simulation results to find the bottlenecks in processes, and a brief analysis of activities costs is presented.

Abstract: In this study, the effects of hardness on temperature increase of ST 37 steel during fatigue loading were investigated. Steel specimens are made of ST 37 steel and subjected to heat treatment to obtain different hardness. The specimens were subjected to reverse bending fatigue loading and the specimens were observed by using a infrared (IR) camera during the test. The obtained thermal images were recorded by FLIR E45 IR camera and then transferred to the image processing program developed by using MATLAB. Thus after image processing, thermal values used to detect the temperature rise of the surface of the steel specimen under fatigue loading were obtained. During the fatigue, the material is subjected to strain energy input which result in plastic or/and elastic deformation. This event results in an increase of temperature within material. The energy conservation requires that the generated heat shows itself as heat transfer by conduction, convection and radiation and internal energy increase. Besides, if the material has undergone plastic deformation, an additional term which accounts this effect should be included within energy conservation equation. In order to observe the effect of plastic deformation upon temperature increase of material, the ability of plastic deformation has been changed through the change of hardness and the thermal variations during fatigue has been investigated.

Abstract: In this study, the temperature rise of composite plates with a hole during fatigue loading was investigated. Woven glass/epoxy composite plates with eight plies were subjected to bending fatigue loading and materials were observed by using a thermal camera during the test. Previous works showed that a heat generation can form due to internal friction and damage formation. Therefore, a thermographic infrared imaging system was used to detect the temperature rise of composite specimens. During the tests, the thermal images of the specimens have been recorded by a thermal camera and then transferred to the image processing program which has been developed by using MATLAB. By using these thermal images, the spot temperatures of the specimen were obtained by using artificial neural networks. The obtained temperatures show local increase at places where the heat generation localized. These regions considered being the probable damage initiation sites. It is shown in this study that most probable damage initiation zones in the woven glass/epoxy composite material can be detected by using infrared thermography (IRT) approach prior to failure.

Abstract: The voltage and electric field distribution in an arrester are very important for its long operation 15 kV with and without pollution. In order to clarify the influence of pollution severity conditions on metal oxide surge arrester, the finite element method (FEM) compilation of the voltage distribution in the ZnO column varistors under different pollution layer conductivity (200 μS, 70μS, 20μS) and clean was employed using the FEMLAB package.

Abstract: Analytical instruments such as optical microscope, SEM and TEM are employed to investigate and analyze the microstructure and characteristics of soldering joint interfacial region. The results indicated that interactive crystallization exists in part of the interfacial region by using a newly developed kind of soldering filler metal. The composition of the interfacial region is complex such that both solid solution of Cd,Sn,Zn and small amounts of fine grained compounds of Mg2Sn,MgZn exist. Solid solution can improve the strength and plasticity, and small amounts of fine-grained compounds can strengthen the matrix which is beneficial for improving the bonding strength. However, successive laminate structure of intermetallic compounds will result in embitterment and deteriorate the properties of the joint.

Abstract: An electromyography (EMG) decoded based virtual artificial intelligence control system has been developed to quantify the performance of real-time control of a multifunctional myoelectric prosthesis. To develop this platform system, a three-dimensional upper limb was simulated by using Solidworks and then implemented into an integrated scene of virtual artificial limb ,which was programmed in virtual reality modeling language (VRML) and performed through Simulink toolbox of the MATLAB. By decoding surface electromyography (sEMG) signals collected from arm muscle surface, the platform system can identify thesix classes of different arm and hand movements and control the virtual artificial limb and/or the physical arms simultaneously. The VR-based platform also provides a relaxant and enjoyable training environment for prosthesis-users in clinic.