Grain growth prediction with inclination dependence of 〈1 1 0〉 tilt grain boundary using multi-phase-field model with penalty for multiple junctions

Multi-phase-field (MPF) model with a higher-order term representing energetic penalty for multiple junctions was proposed to predict the grain growth accompanying the inclination dependence of grain boundary (GB) energy and mobility. The inclination effect was introduced on the basis of GB energy obtained from molecular dynamics (MD) simulations. The preliminary grain growth simulation of an isolated grain surrounded by Σ3 GB certified that the analytical equilibrium shape was well reproduced. The augmented higher-order term added to conventional MPF model could improve convergence and stability of numerical calculations around triple junction (TJ) region even if there exists the large GB energy gap at the TJ. Moreover, the present MPF model can realize well the Young’s relation with no GB inclination effect and further extend to the case with that effect. For the polycrystalline grain growth simulations with the GB energy distribution according to the misorientation angle of Al 〈1 1 0〉 tilt GB, Σ3 GB inclination lead the weak anisotropy characterized by Σ3{111} twin boundary. Besides, the inclination dependence can effectively drive the GBs with low GB energy like the low-angle GB during grain growth.     

Nanoscale contact plasticity of crystalline metal: Experiment and analytical investigation via atomistic and discrete dislocation models

Nanoscale incipient plastic deformation in crystalline metals occurs as the result of the collective motion of dislocations. It is known as “nanoplasticity” and is recognized as the elementary process of the macroscopic deformation. Abrupt increases in indent displacements called displacement bursts were observed in recent nanoindentation experiments; that is, the specific behavior for nanoplasticity. In the present study, experimental tests are first conducted to educe the unique nature of the nanoscale deformation. Subsequently, large-scale atomistic simulations are performed to predict the incipient plastic deformation and a new discrete dislocation model combined with the boundary element analysis is constructed to capture the collective motion of the dislocations. Our results suggest that the incipient plastic deformation requires much higher critical shear stress than the theoretical shear strength due to high compressive stress distribution beneath the indenter, and that the displacement burst is induced by surface rearrangement corresponding to hundreds of dislocation dipoles.     

Development of the Water Cooled Ceramic Breeder Test Blanket Module in Japan

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. In Japan, fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. Important key technologies are almost clarified for the fabrication of the real scale TBM module mockup. From the view point of testing and evaluation, development of the technology of the blanket tritium recovery, development of advanced breeder and multiplier pebbles and the development of the blanket neutronics measurement technology are also performed. Also, tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been started as the verification test of tritium production performance. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.     

Complementation analysis reveals a potential role of human ARV1 in GPI anchor biosynthesis

ARV1 is involved in regulating lipid homeostasis but also in the biosynthesis of glycosylphosphatidylinositol (GPI) in Saccharomyces cerevisiae. Here, we examined whether human ARV1 can complement the role of yeast ARV1 in GPI biosynthesis. Overexpression of human ARV1 could rescue the phenotypes associated with GPI anchor synthesis defect in the yeast arv1Δ mutant. The results suggest that Arv1 function in GPI biosynthesis may be conserved in all eukaryotes, from yeast to humans. Copyright © 2015 John Wiley & Sons, Ltd.     

Evaluation and fabrication of pore‐size‐tuned silica membranes with tetraethoxydimethyl disiloxane for gas separation

Organic/inorganic hybrid silica membranes were prepared from 1,1,3,3‐tetraethoxy‐1,3‐dimethyl disiloxane (TEDMDS) by the sol‐gel technique with firing at 300–550°C in N₂. TEDMDS‐derived silica membranes showed high H₂ permeance (0.3–1.1 × 10^?6 mol m^?2 s^?1 Pa^?1) with low H₂/N₂ (～10) and high H₂/SF₆ (～1200) perm‐selectivity, confirming successful tuning of micropore sizes larger than TEOS‐derived silica membranes. TEDMDS‐derived silica membranes prepared at 550°C in N₂ increased gas permeances as well as pore sizes after air exposure at 450°C. TEDMDS had an advantage in tuning pore size by the “template” and “spacer” techniques, due to the pyrolysis of methyl groups in air and Si? O? Si bonding, respectively. For pore size evaluation of microporous membranes, normalized Knudsen‐based permeance, which was proposed based on the gas translation model and verified with permeance of zeolite membranes, reveals that pore sizes of TEDMDS membranes were successfully tuned in the range of 0.6–1.0 nm. © 2011 American Institute of Chemical Engineers AIChE J, 2011     

基于结构强震记录的结构时变模态参数识别

为研究结构在地震过程中动力特性变化和损伤过程,为结构地震损伤评估提供可靠依据,采用递归式在线系统辨识算法RARX模型,利用结构强震记录识别了结构时变模态参数。以一座6层钢筋混凝土框架结构为例,识别了其时变自振频率、阻尼比和等效刚度。结果发现：在小地震动作用下,结构自振频率随时间几乎不发生改变;在大地震动作用的整个时间过程中,结构自振频率随时间逐渐降低,降低到一定程度到达最低点后,频率开始回升,直至地震结束,但最后不能回升到初始值,说明经历大震发生损伤的结构在震后性能会有所恢复;结构等效刚度变化趋势和自振频率相同,但在大震中下降比频率下降大的多;结构阻尼比在经历大震发生损伤后增大。结果可供结构地震损伤预测及结构震后安全鉴定参考。     

The trend in current and near future energy consumption from a statistical perspective

Energy consumption has increased remarkably over the past half century mainly due to increasing population and economic development. The influences of these two factors are considered. In most developed countries, such as Japan, France, Germany and Korea, the growth rate of energy consumption is due to economic development. The effects of population in Germany and Japan will substantially decline. In the USA, it is due to both factors as well as in the developing countries, such as China, India, Indonesia and Latin America. Economic success is more effective than increasing population in China, India and Indonesia, while both factors are roughly equal in Latin America. In Africa, though the growth rate depends on the effect of increasing population, its contribution to world energy consumption is small. On a worldwide scale, the growth rate of energy consumption will be affected by improving standards of living.     

Ab initio calculations of Fe–Ni clusters

The clusters of Fe, Ni, and Fe–Ni are investigated computationally using a density functional approach. The geometries of clusters are optimized under the constraint of well-defined point group symmetries at the UB3LYP/LanL2DZ level. The equilibrium geometries and binding energies are presented and discussed, together with natural populations and natural electron configurations. In addition, the binding energies of Fe_n−xNi_x clusters are found to generally decrease by successive substitutions of Ni atoms for Fe atoms. For Fe_n−xNi_x clusters, the comparisons on total energies between isomers indicate that Ni atoms energetically prefer clustering in the mixed Fe–Ni clusters. The calculations for Fe_n−xNi_x clusters show that the clustering leads to a segregation of Ni atoms from Fe atoms.     

Improved method to simulate gradient in alumina packing fraction in alumina/epoxy composite fabricated by a centrifugal method

A centrifugal method was used to fabricate large‐scale functionally graded materials (FGMs) from solid‐particles/viscous‐matrix mixtures at room temperature. The conventional simulation procedure of the centrifugal process was improved by considering the dependency of the viscosity η of the mixture on the packing fraction ν_p of particle, the effects of arbitrary shape of the actual fillers on η, the statistical dispersion of the diameters of the actual fillers, and the formation and growth of the fully packed layer (FPL) near the FGM bottom. The new simulation method was applied to three centrifugal processes employed for experimental FGM fabrications from alumina/epoxy mixtures. The numerical profiles of ν_p are in good agreement with the experimental ones regardless of the shapes of fillers and 'ponding viscosity of the solutions without fillers, the total amount of fillers loaded, and the centrifugal conditions. The saturating nature of ν_p near the far end of the FGM column is also simulated with reasonable precision. Finally, the manner in which the particles exert varying influences on the gradient of ν_p is demonstrated: the particles exhibit different movements depending on their size. On the basis of these results, the effectiveness of the new simulation method proposed is confirmed for the modeling of similar processes involved in the fabrication of FGMs from solid‐particles/viscous‐matrix mixtures by the centrifugal method. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.