Advanced Materials Research Vols. 230-232

Abstract: Cross wedge rolling valve roughcast is charactered by minor diameter, long stretching and heavy section shrinkage; however, it is hard to select a set of suitable machining process parameter and prone to rolling internal defect. In order to research this problem, a whole forming process of valve roughcast by single cross wedge rolling is simulated with finite element simulation software DEFORM-3D 6.0, which focuses on the stress and strain of the center point of rolled piece under different forming angles. The rolling experiment under different forming angles was done on H500 rolling mill to calculate and analysis of the areas of the centre holes for each rolled piece. The influence of forming angle on internal defect is discovered by a method combining finite element simulation and experiments. At last, it is concluded that forming angle of 28°can improve the internal defect of valve roughcast formed by single cross wedge rolling.

Abstract: By comparison of the drive systems in electric vehicle and fuel vehicle, this study indicates the main differences of the structures between these two items, and explores the electric retrofit designs of forestry tending vehicles theoretically and practically, upon focusing the developing trend of cleaning environment and based on Tractor 50. On this foundation, the paper finally puts forward to suggestions on retrofit design.

Abstract: This study utilizes mortar specimens, to design 3 different a/c ratios of 2.25, 2.75, and 3.25. The aggregate volume ratios (V_f) are 46 %, 52 %, and 57 %, respectively, while the w/c ratio is 0.5, and undergoing a 9, 12, and 15 A/m2 constant current density Accelerated Lithium Migration Technique after curing for 3 months. Results show that, on specimens applied with the same current density, the time of Li⁺ to pass through the specimen, and steady state flux and migration coefficient all exhibit a positive linear correlation with V_f. At the same time, the non-steady state migration coefficient for Li⁺ have a negative linear correlation with V_f.

Abstract: The numerical simulation of the resistance characteristics of the inertial stage had been researched with different turbulence models, and the resistance characteristic computation curves of the inertial stage with different turbulence models have been obtained. Then curves contrasted with the actual value from experiments. The results show that the error of the Standard model is a little larger, but results of the RNG and Reynolds Stress are comparatively accurate. It has provided the reference frame of the turbulence model selection when the numerical simulation of the inertial stage is conducted.

Abstract: In this paper research has been carried out on the Loss of Coolant Accident (LOCA) in an Integral Pressurized Water Reactor(IPWR) by using thermal hydraulic system code Relap5/Mod3.4.The designing of Integrated Pressurized Water Reactor (IPWR) incorporates the safety and reliability of the reactor to withstand under accidental vulnerabilities. In this study, the reactor under consideration is Uranium Zirconium Hydride Nuclear Power Reactor INSURE-100 with the power output of 100MW.In the current research, the reactor has been described in detail according to the requirement for the simulation of LOCA using Relap5 code with the possibility of occurrence of the time sequence of events. The graphs obtained shows good agreement for the safe operation of IPWR under LOCA.

Abstract: The mesh of the multilayer gauze stage was simplified from the crossing arrangement to the unilateral arrangement, and the simplification from three-dimensional to the two-dimensional came true. The calculation capacity was effectively controlled by means of the periodic boundary. The numerical simulation of the multilayer gauze stage with different layers has been done. After the several calculation with different operating conditions, the resistance characteristic curves of the corresponding models was gave out. The relationship between the layers of the multilayer gauze stage and the resistance characteristic has been worked out. The experiments on resistance specialty of the multilayer gauze stage have been done on the special wind-tunnel. The experiment result was compared with the numerical simulation result, in order to provide the effective information for the further research.

Abstract: Microstructural information obtained for silicon-alloyed pyrolytic carbon coatings used for heart valves using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy is described. The coatings consist of two phases, pyrolytic carbon and β silicon carbide, whose crystallite sizes are small. The coatings are principally composed of spherical particles that are from 300 to 1000 nm in diameter. These spherical particles, between which there are occasionally pores, are welded by laminar carbons. The silicon, content of which is moderate, disperses uniformly in the coatings.

Abstract: With the passage of time, changes occur in components reliability and operating procedures, which continuously modify the configuration of Nuclear Power Plants (NPP). In order to handle these situations, living probabilistic safety assessment (LPSA) and risk monitoring (RM), play an important role in updating and maintaining level of safety. The objective of this paper is to highlight a newly developed risk monitor called Risk Manager that can be used to analyzing data.

Abstract: Nickel hydroxide electrodes with flower-like structure were prepared by pulse electrodeposition method. The samples were characterized by XRD, SEM and electrochemical measurements. XRD results show a typical characteristics of α-Ni(OH)₂. SEM results show the morphology can be controlled by the ratio between on-time (T_on) and off-time (T_off). If T_on is constant to 10s, a flower-like structure will be obtained when T_off is bigger than 20s. Electrochemical tests revealed that the Nickel hydroxide electrodes prepared atT_on=10 s and T_off = 30s not only has higher discharge capacity but also exhibits superior stability of capacity during charge-discharge cycling. The maximum specific capacitance in the first cycle is 737.74 F/g and their specific capacitance become stable after cycling 20 times.

Abstract: In this paper, three-dimensional solid contact finite element model of pin connector was build,and used this model to make careful checks of a variety of analytical algorithms of dangerous section’s stress of lug ,finally established reasonable analytical algorithms of dangerous section’s stress of lug.