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Takahiro Ohmura, Yasuo Ito, Isami Abe, Hiroya Abe, Makio Naito2009 Volume 46 Issue 11 Pages 806-812
Published: November 10, 2009
Released on J-STAGE: January 30, 2010
JOURNAL FREE ACCESSIt has been shown that nanoporous composites made by direct bonding of ceramic fibers and nanoparticles have extremely low thermal conductivity. However, the materials are sintered in high temperature range. Furthermore, it becomes difficult to prevent the radiation heat transfer as the temperature rises. Therefore, it is very crucial to realize thermal insulations with low thermal conductivity and available in higher temperature range. To cope with the problem, we have developed the high performance thermal insulation which is available in high temperature range. First, nanoporous composites are prepared by direct bonding of ceramic fibers and nanoparticles made of the fumed aluminum. Then, the nanoporous materials can be simply formed by dry pressing of the nanoparticle / fiber composites with SiC particles. In this study, we evaluated the effect of the content of SiC particles on the strength and thermal conductivity of the nanoporous materials.
The nanoporous material whose porosity was under 0.9 had the bending strength over 0.2 MPa. SiC particles mainly affected the radiation heat transfer. The thermal conductivity ranged from about 0.038 to 0.048 W / (m·K) in the temperature from 600 to 1000°C. Furthermore, the thermal conductivity obtained by the proposed estimation equation agreed with the measurement result within an error of ±10%.View full abstractDownload PDF (1034K) -
Ken-ichi Sugimura, Nguyen Thi My Diep, Ferry Iskandar, Kikuo Okuyama2009 Volume 46 Issue 11 Pages 813-818
Published: November 10, 2009
Released on J-STAGE: January 30, 2010
JOURNAL FREE ACCESSNi/BaTiO3 core-shell particles were successfully prepared using a spray drying of a slurry precursor comprising Ni particles (100 nm) and BaTiO3 nanoparticles (20 nm) and butyl acetate. In the process, the precursor was atomized using an ultrasonic nebulizer to produce droplets, and subsequently the droplets were fed into a tubular furnace by a carrier gas for evaporating the dispersant. By controlling the pH of precursor, the furnace-temperature profile and the carrier gas flow rate, the Ni/BaTiO3 particles with a core-shell structure could be prepared. In order to characterize the prepared particles, a scanning electron microscopy and an X−ray diffractometer analysis were used.View full abstractDownload PDF (1151K)
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－ISO on Quantitative Representation of Particle Shape－Shigehisa Endoh2009 Volume 46 Issue 11 Pages 819-824
Published: November 10, 2009
Released on J-STAGE: August 31, 2017
JOURNAL RESTRICTED ACCESSOutline of ISO 9276-6: 2008 specifying quantitative representation and description of particle shape is introduced and commented. The shape descriptors defined in the standard are mainly introduced. At first, this standard is treating a digitized image or a binary image of an arbitrary particle. The shape description methods and their descriptors are classified based on the size level of the measurement into macrodescription, methodescription and microdescription. This means that the shape properties are different according to the measurement at the different size level. Finally the necessary shape descriptor set for comparison of shape analyzing methods and devices are defined by this standard.
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Hideki Kanda, Hisao Makino2009 Volume 46 Issue 11 Pages 825-827
Published: November 10, 2009
Released on J-STAGE: August 31, 2017
JOURNAL RESTRICTED ACCESSWe have developed an energy-saving dewatering method using liquefied dimethyl ether. This new method is capable of efficiently extracting the water from high moisture coal and sewage sludge at ordinary temperatures, increasing the calorific value per weight, and rendering these substances easier to use. Further, large amounts of energy are required for the cleanup of the oil-polluted ground. Water contained in the soil hinders the extraction processes that involve the use of organic solvents. Therefore, we apply the dewatering technique to cleanup the oil-polluted ground. On the basis of our prototype plant experience, we can achieve almost 100％ removal of water and other oily materials from the oil-polluted ground. We shall collaborate with some universities and companies for the cleanup of river and harbor sediments that are polluted with polychlorinated biphenyls and dioxins.
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