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Mihara, Morihiro; Harasawa, Shuichi*; Torii, Kazuyuki*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.15 - 23, 2019/06
Hardened cement pastes (HCPs) of water/cement ratio (W/C) 50% and 30% using fly ash (FA), blast furnace slag (BFS) and silica fume (SF) for 28 days were prepared. Apparent diffusion coefficients (D
) of Cs and I in HCPs were obtained using electron probe microanalysis. For Cs, BFS and SF contributed to a reduction of D for W/C=50% and 30%, respectively. For I, BFS reduced D for W/C=50%, however a significant reduction in D for W/C=30% was not observed. Using SF enhanced sorption of Cs on HCP, and using BFS slightly improved sorption of Cs on HCP. It was also confirmed that the pore structures of HCP using SF and BFS were connected by fine pores. It was therefore considered that using SF and BFS contributes to the reduction of D in HCP.
Seko, Noriaki; Tamada, Masao; Yoshii, Fumio
Nuclear Instruments and Methods in Physics Research B, 236(1-4), p.21 - 29, 2005/07
Times Cited Count：104 Percentile：98.74(Instruments & Instrumentation)Removal of toxic metals from streaming water and ground water is important task to preserve environment. Radiation processings of grafting and crosslinking can synthesis adsorbent having high performances. Graft adsorbent can be synthesized by using the conventional polymer like polyethylene having variety shapes such as membrane, cloth, and fiber. Especially, the obtained fibrous adsorbent has 100 times higher rate of adsorption than that of commercialized resin. Novel fibrous adsorption for arsenic was synthesized by direct grafting of phosphoric monomer and following zirconium-loading. Fibrous adsorbents of amidoxime and iminodiacetate were applied to the removal of cadmium from the scallop waste. Furthermore, the amidoxime adsorbent is useful to recover rare metal such as uranium and vanadium in seawater. Crosslinked natural polymers like chitin-chitosan in the paste-like state are applicable for the metal adsorbent. This adsorbent can be biodegraded after usage.
Wach, R. A.*; Mitomo, Hiroshi*; Yoshii, Fumio; Kume, Tamikazu
Macromolecular Materials and Engineering, 287(4), p.285 - 295, 2002/04
Times Cited Count：58 Percentile：85.14(Materials Science, Multidisciplinary)no abstracts in English
Wach, R. A.*; Mitomo, Hiroshi*; Yoshii, Fumio; Kume, Tamikazu
Journal of Applied Polymer Science, 81(12), p.3030 - 3037, 2001/09
Times Cited Count：115 Percentile：95.3(Polymer Science)no abstracts in English
Yoshii, Fumio
Mizu, (612), p.16 - 22, 2001/06
no abstracts in English
Yoshii, Fumio
Kombatekku, 28(12), p.32 - 35, 2000/12
no abstracts in English
Fei, B.*; Wach, R. A.*; Mitomo, Hiroshi*; Yoshii, Fumio; Kume, Tamikazu
Journal of Applied Polymer Science, 78(2), p.278 - 283, 2000/10
Times Cited Count：192 Percentile：98.21(Polymer Science)no abstracts in English
Yoshii, Fumio
Hoshasen To Sangyo, (87), p.55 - 58, 2000/09
no abstracts in English
Yoshii, Fumio
Hoshasen To Sangyo, (87), p.55 - 58, 2000/09
no abstracts in English
Owada, Hitoshi*; Mihara, Morihiro; Iriya, Keishiro*; *
JNC TN8400 99-057, 43 Pages, 2000/03
Cementitious materials are considered as candidate materials for the geological disposal of high-level radioactive waste and TRU waste. As the pH and the Ca content of leachate from the cementitious materials are high, the host rock and the buffer-material would be degraded by the leachate in the long-term. Therefore, transport properties and parameters such as solubilities and distribution coefficients of radionuclides would be changed and affect the performance of the repository. In order to dissolve this "High pH plobrem", the use of a low alkalinity cement is considered for the disposal. In this study, we summarized the necessity of the low alkalinity cement, and developed the approach of the low alkalinization of cement. And, the following were carried out in this study : A leaching test of cement paste, a fluid test of the mortar and a installation test of the concrete to the trial structure. From the leaching test using the cement paste, we confirmed that we were able to obtain the low alkalinity cement (HFSC) by addition of pozzolanic materials such as silica-fume and flyash. From the result of the fluid test of the mortar, we chose the cement for the practicability evaluation. The practicability of low alkalinity concrete was evaluated by installation test to the trial structure.As a result of these examinations, we proved that the pH value of the leachate from the cementitious material was reduced by adding SF and FA to Portland cement. Simultaneously, SF and FA had to be added in order to obtain the good workability. In addition, workability and mechanical strength of the cement which SF and FA were added are almost equivalent to the ordinary Portland cement. The results shows that the HFSC has high practicability.
Tanaka, Satoru*
JNC TJ8400 2000-003, 62 Pages, 2000/02
JNC-TJ8400-2000-003.pdf:11.88MB
For the safety assessment of radioactive waste disposal, it is important to elucidate the effect of colloids on radionuclide migration, which are released with dissolution of cementitious materials composing engineered barricr. In the previous work, we identified and characterized the colloidal particles in the solutions contacting cement hydrates, OPC and low-alkaline cement paste, and observed the release of the colloid particle. In the present work, we performed same experiments as the last year to confirm the reproducibility of the colloid release. We studied the leaching behavior of the colloid when OPC and low-alkaline cement past contact water flow. Furthermore, the effect of an alumina particle was studied, which is used as a barrier material for colloid migration. The following conclusions were derived: (1)In the solution contacting cement paste, the small amount of particles, which are considered as CaCO
or silicate colloids were observed. Thus, the reproducibility of the last work was confirmed. (2)The leaching of colloid in the solution was confirmed by water flow through the cement paste. The concentration of particle was as low as 10
10
mL
. (3)Al
0 powder, with the diameter of 200150
m, was found to be effective to some extent as a barrier for a colloid migration from low-alkaline cement paste.
Wach, R. A.*; Mitomo, Hiroshi*; Yoshii, Fumio; Kume, Tamikazu
IAEA-SM-365, p.174 - 175, 2000/00
no abstracts in English
Yoshii, Fumio; Nagasawa, Naotsugu*; Mitomo, Hiroshi*; Kume, Tamikazu
IAEA-SM-365, p.164 - 165, 2000/00
no abstracts in English
-caprolactone/
-valerolactone) and estracyt or estramustine*; Yoshida, Masaru; *; Asano, Masaharu; Kumakura, Minoru*; Mashimo, Toru*; Yamanaka, Hidetoshi*; *
Chemical and Pharmaceutical Bulletin, 39(8), p.2096 - 2099, 1991/00
no abstracts in English
-caprolactone and -valerolactone in the absence of catalysts*; *; Yoshida, Masaru; *; Asano, Masaharu; Kumakura, Minoru
European Polymer Journal, 26(8), p.831 - 836, 1990/00
Times Cited Count：18 Percentile：65.39(Polymer Science)no abstracts in English
-valerolactone with relatively low molecular weight for application in drug delivery systems*; Yoshida, Masaru; Asano, Masaharu; Kumakura, Minoru; Mashimo, Toru*; Yuasa, Hisako*; Imai, K.*; Yamanaka, Hidetoshi*; *; Suzuki, K.*
Journal of Controlled Release, 10, p.293 - 303, 1989/00
no abstracts in English
Kawato, Takaya*; Ishida, Keisuke*; Yamamoto, Takeshi*; Minato, Daisuke*; Fujisaki, Kiyoshi*; Hamamoto, Takafumi*; Mihara, Morihiro
no journal, ,
no abstracts in English
