Papers by Author: Takanori Watari

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Authors: Rumi Chand, Takanori Watari, Toshio Torikai, Mitsunori Yada, Katsutoshi Inoue
Abstract: Porous carbon having surface area of 792 m2g-1 was prepared from barley straw by carbonization at 800 oC at a heating rate of 5 oCmin-1 to test the chromium (VI) adsorption from aqueous solution. The effects of pH, contact time and equilibrium Cr (VI) concentration on the adsorption were studied in detail. The optimum pH for Cr (VI) removal was found to be 2. The adsorption of Cr (VI) was very rapid and equilibrium was reached within 1 h. It was interpreted in terms of adsorption-coupled reduction mechanism. Accompanied by the decrease of Cr (VI) ion, Cr (III) ion was slightly released in the solution. Maximum loading capacity of total chromium was found to be 2.35 molkg-1 at pH 2.
Authors: Takanori Watari, Toshio Torikai, Y. Imaoka, W.-P. Tai, O. Matsuda
Authors: Takanori Watari, Katsuhiro Ogawa, Toshio Torikai, Mitsunori Yada, Masaki Akiyama, Masaki Ida
Abstract: Porous plate with bimodal size distribution was prepared using the molten slag from the incinerator. The slag was pulverized to 1-10μm using a planetary ball mill. On heating the pellet formed with this powder, its relative density at 750°C and 800°C were 70% and 85%, respectively. At 750°C, each particle partially attached together at the contacted point. At 800°C, however, all particles melted, coagulated together and increased their size. The slag powder was granulated using a tumbling granulator, resulting granules of 0.5-5mm size. The compressive strength of the granule sintered at 750°C was 0.39 kgf. The density of the granule decreased by ~60%. The sintered granules were mixed with a proper amount of glass powder and starch water, and the slurry was cast to a mold (φ80mmx10mm). After drying the cast plate, it was heated at 630°C. The density of the plate was 1.2 gcm-3, ~43% of original slag value. The sound absorption coefficients of the plate were 0.02 and 0.4 at 200Hz and 1500Hz, respectively.
Authors: Takanori Watari, Gosuke Shiraishi, Kohei Nagata, Toshio Torikai, Sachiko Furuta
Authors: Takanori Watari, Satiyo Taniguchi, Toshio Torikai, Mitsunori Yada, Sachiko Furuta
Authors: Hom Nath Luitel, Takanori Watari, Toshio Torikai, Mitsunori Yada
Abstract: Sr4Al14O25:Eu2+, Dy3+ long persistent phosphors with different B, Eu and Dy contents were prepared by solid phase reaction at various temperatures in H2/N2=1/9 atmosphere. X- ray diffraction and scanning electron microscopy observations showed that, when the phosphor was doped with 40 at% B, single dense Sr4Al14O25 phase was formed but for the samples with less than 40 at% B, mixed phases containing SrAl12O19 and SrAl2O4 were observed while for higher B content (100 at%) SrAl2B2O7 phases appeared. The phosphor showed emission peak centered at 500 nm with blue green color. When 40 at% of H3BO3 was added and doped with 4 at% of Eu and 8 at% of Dy, it showed the maximum initial intensity of 3170 mcd.m-2 and the longest persistency which is greater than 20 h over value of 5 mcd.m-2.
Authors: Toshio Torikai, Takaharu Ishibashi, Kiichiro Egoshi, Mitsunori Yada, Takanori Watari
Authors: Y. Shima, H. Hasuyama, T. Hiramitsu, W.-Y. Fan, Y. Imaoka, Takanori Watari, K. Baba, R. Hatada
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