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Sekine, Yurina; Nankawa, Takuya; Hiroi, Kosuke; Oba, Yojiro*; Nagakawa, Yoshiyasu*; Sugita, Tsuyoshi; Shibayama, Yuki; Ikeda-Fukazawa, Tomoko*
Carbohydrate Polymers, 327, p.121538_1 - 121538_11, 2024/03
Times Cited Count：0 Percentile：0.01(Chemistry, Applied)We describe non-toxic, tough nanocellulose (NC) hydrogels formed from chemically unmodified NC by cellulose crystalline transformation and subsequent freeze cross-linking reaction. Using low-concentration NaOH and freezing together induced the crystalline transformation of NC from cellulose I to II via freeze concentration. After the crystalline transformation, cross-linking between the NC and CA in the freeze concentration layer (FCL) provided a strong NC network structure, forming NC hydrogels with high mechanical strength. The freeze-cross-linked NC hydrogel easily retained powder adsorbents in its inner space by mixing the NC-NaOH sol and the powder, and the hydrogel showed high removal efficiency for heavy metals. The results highlight the versatility of chemically unmodified celluloses in developing functional materials, suggest possible practical applications.
Sekine, Yurina
Cellulose Communications, 30(4), p.203 - 208, 2023/12
In this paper, we introduce the fabrication and properties of carboxymethyl cellulose nanofiber (CMCF) hydrogels with high compression recoverability, macroporosity, and nontoxic properties by utilizing the phase separation phenomenon of ice crystals and solutes that occurs during freezing of aqueous solutions. The features of the developed freeze cross-linked CMCF hydrogel include that it can be made from harmless raw materials with simple procedure, high water content, and biodegradability. By taking advantage of these properties, this hydrogel synthesis technique can contribute to expanding the use of cellulose derivatives as environmental purifiers, functional materials, etc.
Kawase, Keiichi
Kankyo Hoshano Josen Gakkai-Shi, 9(4), p.171 - 172, 2021/12
no abstracts in English
Sawaguchi, Takuma; Takai, Shizuka; Takeda, Seiji
JAEA-Research 2020-005, 47 Pages, 2020/06
JAEA-Research-2020-005.pdf:5.09MB
After the Fukushima Daiichi Nuclear Power Station accident, large quantities of radiocesium-contaminated soil were generated from decontamination activities in the Fukushima prefecture. The removed soil has been stored in the prefecture until its final disposal. To complete the final disposal outside Fukushima prefecture, reducing the disposal volume through recycling can prove effective. The Ministry of the Environment, Japan (MOE) has presented a policy to recycle low-radioactive removed soil as recycled materials under the management of public authority. The recycling is limited to civil engineering structures in public projects. In this study, to contribute to guideline development for removed soil recycling by MOE, dose estimation in recycling of removed soil as embankment materials of seaside protection forest was conducted. First, additional doses to workers and the public in construction and service scenarios were evaluated. From the result, the radioactive cesium concentration level of recycled materials, where all additional doses meet the radiation criterion of 1 mSv/y, was derived to be 5,000 Bq/kg. Then, construction conditions were reviewed to reduce additional doses to the public in a service scenario. With the derived radioactivity level of 5,000 Bq/kg, the covered soil thickness of 39 cm or more limited the doses to less than 10 
Sv/y. Finally, additional doses in a disaster scenario were evaluated. The doses were confirmed to be below 1 mSv/y when the removed soil of 5,000 Bq/kg was used.
Sato, Hiroyuki; Yan, X.
Nuclear Engineering and Design, 343, p.178 - 186, 2019/03
Times Cited Count：11 Percentile：77.44(Nuclear Science & Technology)A hybrid system combining HTGR and renewable energy is investigated to compensate intermittent renewable energy power generation. A new proposal of using the inventory and bypass control devices already built in the gas turbine, is found to be effective to compensate hourly to daily variation of renewable energy. The reactor thermal power remains at constant full power while the heat output is increased or decreased subject to the need of reactor power generation. On the other hand, the massive heat capacity in the graphite core is shown to be sufficient to compensate renewable energy on a time scale of seconds to minutes and up to about 20% of the rated power output of the nuclear plant. Similarly, no additional control devices are required to perform this control operation. These findings demonstrate the technical and economic potential of the HTGR system to maintain the stability of a grid being incorporated with significant portfolios of renewable energy power generation.
reductionYan, X.; Sato, Hiroyuki
IAEA-TECDOC-1885, p.121 - 129, 2019/00
The present study proposes a HTGR renewable hybrid cogeneration plant which can contribute to a grid stability for large penetration of variable renewables. In addition, results of control simulations for representative load-following operations, economics assessment and CO reduction assessment are provided.
Takai, Shizuka; Sawaguchi, Takuma; Takeda, Seiji
Proceedings of International Waste Management Symposia 2018 (WM2018) (Internet), 14 Pages, 2018/03
After the Fukushima Nuclear Power Station accident, large quantities of radiocesium-contaminated soil generated from decontamination activities have been stored in the Fukushima prefecture. To complete the final disposal of decontamination soil, the Ministry of the Environment of Japan presented policy to reduce the disposal volume by using low-level decontamination soil as recycled materials. The use will be limited to civil engineering structures in public projects, such as coastal levee and road embankment. However, there has been no example or safety assessment of recycling of decontamination soil. To contribute to guideline development for the recycling by the Ministry of the Environment, we conducted the safety assessment for recycling of decontamination soil as coastal levee. First, we evaluated additional doses to workers and the public in the case of construction and service of coastal levee. From the result, the radioactive cesium concentration level of recycled materials was derived to be 6,800 Bq/kg. For general designs of coastal levee in Japan, additional doses to the public in the case of service were below 0.01 mSv/y with derived radioactivity level. Finally, we confirmed additional doses in the case of disaster to be below 1 mSv/y.
Okada, Takashi; Takeda, Seiji; Nakata, Hisakazu
Nihon Genshiryoku Gakkai-Shi ATOMO
, 59(10), p.603 - 607, 2017/10
Because the reclaimed material is used, quantity of disposal of the removal soil can decrease. It is a strategic key to utilize the reclaimed material. As for this report, it is explained to about the fundamentals of the safe use of the reclaimed materials derived from the removed soil.
Sawaguchi, Takuma; Takai, Shizuka; Umezawa, Katsuhiro; Takeda, Seiji; Okada, Takashi
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(8), p.445 - 447, 2017/08
no abstracts in English
Yaita, Tsuyoshi; Honda, Mitsunori; Shimoyama, Iwao; Ito, Kenichi*; Mampuku, Yuzo*; Tsuji, Takuya; Matsumura, Daiju
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(8), p.483 - 487, 2017/08
no abstracts in English
O
ceramic thin diskMaruyama, Momoko; Okada, Hajime; Ochi, Yoshihiro; Nagashima, Keisuke
Optics Express (Internet), 24(2), p.1685 - 1692, 2016/01
Times Cited Count：5 Percentile：30.58(Optics)We have developed a 1 kHz regenerative amplifier using an Yb:YO ceramic thin disk as the gain medium. Furthermore, the thermal conductivity and heat generation property of Yb: YO ceramic were investigated. In the developed regenerative amplifier, a laser beam is bounced off the thin disk six times in each round trip. The output energy is over 2 mJ, spectral bandwidth is 1.8 nm at FWHM, and pulse duration after pulse compression is 0.9 ps.
Ishiyama, Shintaro
Nihon Kinzoku Gakkai-Shi, 68(7), p.490 - 497, 2004/07
Times Cited Count：0 Percentile：0.01(Metallurgy & Metallurgical Engineering)SUS304 multi stage blazed fin core body for GTHTR300 was tested its high temperature strength, fatigue and creep and it was found that the body behaves as same strength of SUS304 material.
Yamakawa, Koichi; Barty, C. P. J.*
Optics Letters, 28(23), p.2402 - 2404, 2003/12
Times Cited Count：32 Percentile：76.2(Optics)no abstracts in English
Nishioka, Hajime*; Kawanaka, Junji
Hikari Araiansu, 14(11), p.21 - 25, 2003/11
no abstracts in English
Kawanaka, Junji; Yamakawa, Koichi; Nishioka, Hajime*; Ueda, Kenichi*
Optics Letters, 28(21), p.2121 - 2123, 2003/11
Times Cited Count：86 Percentile：93.68(Optics)no abstracts in English
Yamakawa, Koichi
JAERI-Research 2003-017, 9 Pages, 2003/09
JAERI-Research-2003-017.pdf:0.93MB
We have developed a high-energy, ultrabroadband Ti:sapphire ring regenerative amplifier capable of producing in excess of 20mJ output at a 10Hz repetition rate. The technique of chirped-pulse amplification is used to generate two-color, time-synchronized pulses, with central wavelength separations up to 
120nm and with a total energy of 10mJ by using a regenerative pulse shaping technique.
Takada, Shoji; Takizuka, Takakazu; Kunitomi, Kazuhiko; Yan, X.; Minatsuki, Isao*
Dai-31-Kai Gasu Tabin Teiki Koenkai Rombunshu, p.55 - 60, 2003/06
no abstracts in English
Matsui, Shingo*; Muto, Yasushi*; Shiina, Yasuaki
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(2), p.175 - 186, 2003/06
no abstracts in English
Ishiyama, Shintaro; Muto, Yasushi
Nihon Kikai Gakkai Rombunshu, A, 69(679), p.682 - 688, 2003/03
no abstracts in English
Takada, Shoji; Takizuka, Takakazu; Kunitomi, Kazuhiko; Yan, X.; Katanishi, Shoji; Kosugiyama, Shinichi; Minatsuki, Isao*; Miyoshi, Yasuyuki*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 1(4), p.341 - 351, 2002/12
no abstracts in English
