Investigation of the Surface Removal Process of Silicon Carbide in Elastic Emission Machining

Elastic emission machining (EEM) is a precise surface preparation technique, which uses chemical reactions between the surfaces of the workpiece and fine powder particles. The purpose of this study is to clarify the surface removal process of silicon carbide (SiC) in EEM. A SiC sample with a periodic step-bunched structure was prepared as the initial surface and was flattened by EEM. Optical interferometer and atomic force microscopy (AFM) observations show that the topmost areas on the periodic step-bunched structure in contact with the powder particles are preferentially removed and surface protrusion is gradually reduced as removal depth increases. Moreover, power spectral density analyses reveal that the surface is smoothed in the spatial wavelength range from 0.07 μm to 10 μm.     

Rupture Strength of some Mould Flux Slag Films relevant to Swedish Continuous Casting Practice

In this paper, the high temperature rupture strengths of some solid mould flux slag films in Swedish continuous casting processes are presented. The apparatus, designed and constructed in the present laboratory is based on the principle that the solidified film of the mould flux slag is subjected to elongation stress at temperatures below the solidus points of the fluxes. The rupture strength tests were conducted in air. The results indicate that the rupture strength is dependent on the extent of polymerization of the silicate network. The results of Raman spectra studies of the mould flux slags used in the present work were corroborated by estimations of the NBO/T ratios of the slags. It was found that lower NBO/T ratios in the slag led to higher rupture strengths. Earlier measurements of the viscosities, thermal diffusivities as well as stress relaxation results for the same slags followed a similar trend indicating the dependency of these properties on the slag structure and a clear link between thermophysical and mechanical properties of slags. The results are expected to provide some basic guidelines to develop the next‐generation mould flux and modelling of the continuous casting process.     

Practical studies on rockfall simulation by DDA

In this paper,simulations of real rockfall by discontinuous deformation analysis (DDA) are conducted.In the simulations,the energy losses of rockfall are categorized into three types,i.e.the loss by friction,the loss by collision,and the loss by vegetation.Modeling of the energy loss using absolute parameters is conducted by the DDA method.Moreover,in order to verify the applicability and validity of the proposed DDA,field tests on rockfall and corresponding simulations of rockfall tests by DDA are performe...     

Effect of oxygen gas on the decomposition of dye by pulsed discharge in water droplet spray

The influence of stresses on the magnetic properties of nonoriented electrical steels was studied. The dependence of iron loss on compressive stress was affected by grain size. The magnetic polarization J in strong magnetic fields such as 5000 and 10,000 A/m increased due to compressive stresses and decreased due to tensile stresses in samples with low Si content. Using Kerr‐effect domain observation, it was found that the reduction in J caused by tensile stresses was attributable to residual striped domains. Magnetostriction measurements in strong magnetic fields indicated that the increase in J under compressive stresses originated from the Villari effect (inverse magnetostrictive effect) due to negative magnetostriction in low‐Si materials. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(4): 10–18, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22320     

三维非连续变形分析(3D DDA)理论及其在岩石边坡失稳数值仿真中的应用

在3D DDA中，分析的块体是由岩体内部实际存在的不连续面切割而成。在计算过程中，利用块体的几何关系正确地寻找出可能产生接触碰撞的块体，并在块体接触时利用接触弹簧来评估接触面法线方向的接触力：另外，在剪切方向则遵守摩尔-库仑破坏准则，最后以独创的开合迭代方法来保证每一计算步长具有较准确的接触力和解算的收敛性。计算的结果与位于日本天鸟桥西的现场监测影像进行对照后发现，此新计算法可以高精度地预测岩体失稳过程。—