The Accident at Three Mile Island
A. J. McEVILY, Jr. and Iain Le MAY
Review Paper (Vol.8 No.1)
The Accident at Three Mile Island |
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A. J. McEVILY, Jr. and Iain Le MAY |
1 |
General Papers (Vol.8 No.1)
Rheological Behavior during Phase Separation Induced by UV Curing |
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Su-Yong NAM, Mikihiro SAKAI and Yasufumi OTSUBO |
9 |
Effective Young's Modulus of a Composite Including Two Groups of Periodically Arranged Inclusions |
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Nao-Aki NODA, Hironobu NISITANI, Yasushi TAKASE and Takashi WADA |
14 |
The Evolution of Shear Deformation Texture and Grain Refinement in Asymmetrically Rolled Aluminum Sheets |
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Su-Hyeon KIM, Jong-Ho RYU, Keun-Hwan KIM and Dong Nyung LEE |
20 |
X-Ray Study on Lattice Strain and Domain Switching Induced in Rhombohedral PZT by Poling and External Loading |
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Kaori SHIRAKIHARA, Keisuke TANAKA, Yoshiaki AKINIWA, Yoshihisa SAKAIDA and Hirokatsu MUKAI |
26 |
Stereoscopic Fracture Surface Analysis by SEM Using Advanced Stereo Matching |
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Jun JIANG and Shinsuke SAKAI |
32 |
Performance of Carbonized Sugi Wood and Bark for Humidity Control |
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Yasuji KURIMOTO, Kouko KANO, Misato NORIMOTO and Osamu SAWABE |
38 |
Vol.8 No.1 ABSTRACT
The Accident at Three Mile Island
A. J. McEVILY, Jr. and Iain Le MAY
Abstract:This paper discusses the sequence of events involved in the accident which took place at the Three Mile Island Nuclear Plant in Pennsylvania, USA in 1979, the worst nuclear disaster in US history. The physical characteristics of the as-built reactor building are described, and the changes brought about by the accident on the plant structure are discussed. The current state of the plant and the materials of the reactor are also discussed. Key Words:Failure analysis, Three Mile Island, Nuclear power plants, Pressurized water reactor, Meltdown
Rheological Behavior during Phase Separation Induced by UV Curing
Su-Yong NAM, Mikihiro SAKAI and Yasufumi OTSUBO
Abstract:The rheological changes during UV curing are examined for solutions of UV-reactive acrylic prepolymer and alkyd resin. To measure the dynamic viscoelasticity in the entire process of UV curing by a single run, a rheological program is developed, by which the storage modulus can be detected in the range of 100-108 Pa under linear conditions. The solutions containing alkyd resin at concentrations of 10-30wt% show phase separation in the course of curing. The storage modulus of such systems rapidly increases at first, goes through a maximum and then decreasingly approaches the equilibrium value. The microscopic observation of cured films clearly indicates that the droplets generated by phase separation can grow and migrate in the three-dimensional network. The growth of droplets accompanies the rupture of continuous network in a narrow range. The delicate balance between the local rupture of network by phase separation and formation of crosslinks by polymerization controls the appearance of peak in the time-dependent curve of storage modulus. Key Words:Dynamic viscoelasticity, UV curing, Phase separation, Network polymerization, Crosslinking, Gelation, Acrylic prepolymer, Alkyd resin
Effective Young's Modulus of a Composite Including Two Groups of Periodically Arranged Inclusions
Nao-Aki NODA, Hironobu NISITANI, Yasushi TAKASE and Takashi WADA
Abstract:In this paper, the effects of shape and arrangement of inclusions on the effective Young's modulus of materials are considered by the application of the finite element method through examining a model, which has two groups of periodically arranged inclusions in a matrix. Here, two groups of inclusions A and B are considered, both having equally shaped equally arranged inclusions, which have the same elastic constants but different from the ones of the matrix. This model includes square and hexagonal arrays of inclusions as its special cases. First, the effect of shape of inclusions on the Young's modulus of composite materials is considered from the comparison between the results of rectangular and elliptical inclusions. Next, when the position of group A is fixed, the effect of location of group B is considered. Then, the effective elastic Young's modulus is almost independent of the location of group B if the projected areas of groups A and B are not overlapped. In conclusion, the volume fraction of inclusion and projected area fraction of inclusions are found to be two major parameters controlling the effective Young's modulus of composites. Key Words:Micromechanics, Rule of mixture, Composite material, Finite element method, Effective elastic modulus
Su-Hyeon KIM, Jong-Ho RYU, Keun-Hwan KIM and Dong Nyung LEE
Abstract:Asymmetric rolling, in which the ratio of upper to lower roll diameter is different, has been used to introduce an intense plastic shear strain for the purpose of obtaining higher plastic strain ratios due to uniform development of shear deformation textures through the thickness and of grain refinement in aluminum sheets. A commercial purity aluminum sheet was asymmetrically cold rolled under various schedules. The textures, microstructures and strengths of the rolled sheets were investigated. When subjected to several passes of asymmetric rolling by over 90%, the textures approaching to the ideal shear deformation texture consisting of {001}<110>, {111}<110> and {111}<112> developed throughout the thickness. Transmission electron microscopy and electron back-scatter diffraction analyses showed that the sheets have fine-grained structures with large misorientations. Unidirectional rolling in which the rolling direction does not change between passes gave rise to more uniformly refined structures than alternating direction rolling in which the rolling direction is rotated through 180o about the rolling direction between passes. Key Words:Asymmetric rolling, Aluminum, Shear deformation texture, Grain refinement
Kaori SHIRAKIHARA, Keisuke TANAKA, Yoshiaki AKINIWA, Yoshihisa SAKAIDA and Hirokatsu MUKAI
Abstract:The X-ray diffraction method was applied to measure the change of the lattice strain and domain switching in rhombohedral lead zirconate titanate (PZT) due to poling and external straining. The lattice strain was determined from the linear relation between the diffraction angle 2 and sin2 ( is the angle between the normals of the specimen surface and of the diffraction plane). The lattice strain measured by X-rays is at most 15 % of the macrostrain determined from the dimensional change due to poling. Domain switching caused a major part of the macrostrain. External loading induced domain switching and the lattice strain. The lattice strain induced by external loading was at most 25 % of the applied strain. The amount of domain switching was evaluated by the change of the intensity ratio, I222I22-2, of the 222 to 22-2 diffraction. The intensity ratio for the normal diffraction ( = 0) was decreased with increasing the applied strain, because the spontaneous polarization direction, the 222 direction, turned to the loading direction. The broadening of X-ray diffraction profiles obtained from the diffraction plane perpendicular to the poling direction was the maxi-mum, indicating the largest microstrain in the poling direction. Key Words:X-ray diffraction method, Lead zirconate titanate, Rhombohedral PZT, Lattice strain, Domain switching, Spontaneous polarization, Intensity ratio, External loading
Stereoscopic Fracture Surface Analysis by SEM Using Advanced Stereo Matching
Jun JIANG and Shinsuke SAKAI
Abstract:3-dimensional analysis of fracture surface by SEM (Scanning Electron Microscope) is inevitable to clarify the cause of fracture. It is effective to analyze with stereo matching. However, conventional template matching method to measure 3-dimensional profile of fracture surface usually employs fixed template size and has deficiencies such as mismatching and consuming much processing time. Therefore, in this paper, a new stereo matching algorithm is developed, which cannot only save processing time but assure accuracy. In this new template matching method, template size is varied to assure accuracy and lessen mismatching points. In order to shorten processing time greatly, when calculating the correlation coefficient of image template pixels to search the matching templates, all the pixels in templates are not employed, but it is proposed that one pixel is chosen every 2 or several pixels in the same positions of the two templates. In order to investigate the precision and the usefulness of the proposed method, two examples of reconstructing fracture surfaces are successfully shown. It is practically realized to measure three-dimensional profile of fracture surface in personal computer. Key Words:Fractography, 3-dimensional measurement, SEM, Stereo matching, Algorithm, Fracture surface, Fracture
Performance of Carbonized Sugi Wood and Bark for Humidity Control
Yasuji KURIMOTO, Kouko KANO, Misato NORIMOTO and Osamu SAWABE
Abstract:Sugi (Japanese cedar, Cryptomeria japonica D. Don) wood or bark were heated at 500 - 900 for 3h to investigate the effect of treatment temperature on the surface properties and the humidity control capacity of carbonized materials. The specific surface area of micropore (pore radius = 0.64 - 1.0 nm) and mesopore ( >1.0nm) were estimated by the adsorption I sotherm of nitrogen gas at 77K. The humidity control tests were carried out in a sealed batch system at a temperature range of 15 - 25 for 3 - 24h cycles. The initial relative humidity (RH) at 20 was 65%. The micropore surface area of the carbonized woods varied depending on the treatment temperature. These increased significantly from 0 m2/g to 441 m2/g when the temperature increased from 500 to 900. In contrast, the mesopore surface area was almost constant regardless of the treatment temperature, being 39 - 79 m2/g. The maximum performance of humidity control was obtained with the wood or bark carbonized at 600 in 3h and 6h cycles. The change in RH for 24h cycle at the sample of 3.0 mg/cm3 was kept within a range of 3%. In addition, the ability for 3 to 24 hour-cycle humidity control was equivalent to that of 1 to 3/5 of a commercial silica gel used in museums. Carbonized wood and bark prepared at any temperature did not differ from un-carbonized wood in the humidity control capacity at 24h cycle. Key Words:Sugi, Cryptomeria japonica, Carbonization, Humidity control, Carbonized wood