Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 62

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Nanocellulose hydrogels formed via crystalline transformation from cellulose I to II and subsequent freeze cross-linking reaction

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

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.

Journal Articles

Upgrade of the small-angle neutron scattering diffractometer SANS-J at JRR-3

Kumada, Takayuki; Motokawa, Ryuhei; Oba, Yojiro; Nakagawa, Hiroshi; Sekine, Yurina; Micheau, C.; Ueda, Yuki; Sugita, Tsuyoshi; Birumachi, Atsushi; Sasaki, Miki; et al.

Journal of Applied Crystallography, 56(6), p.1776 - 1783, 2023/12

The combination of the existing position-sensitive photomultiplier and the 3He main detector with focusing devices, and the newly installed front detectors in SANS-J at JRR-3 covers small-angle neutron scattering signals in the range of the magnitude of the scattering vector Q from 0.002 to 6 nm-1 gaplessly with three standard device layouts. The installation of the front detector and a graphical user interface system largely improved the usability of SANS-J.

Journal Articles

Conversion of clay minerals to photocatalysts for Cr$$^{VI}$$ reduction and salicylic acid decomposition

Sugita, Tsuyoshi; Mori, Masanobu*; Shimoyama, Iwao

Applied Clay Science, 243, p.107074_1 - 107074_8, 2023/10

We have investigated the conversion of biotite, a subgroup of clay minerals, into photocatalysts by heat treatment with CaCl$$_{2}$$. The reaction products obtained after heat treatment were examined in terms of composition, structure, and photocatalytic activity against Cr$$^{VI}$$ and salicylic acid (SA). When mixtures of biotite and CaCl$$_{2}$$ were heated at temperatures up to 600$$^{circ}$$C, the biotite crystal structure was retained, whereas a phase transformation from biotite to octahedral wadalite crystals occurred upon heating to 700$$^{circ}$$C. The photocatalytic reduction rate of Cr$$^{VI}$$ per unit surface area and the photocatalytic degradation efficiency of SA increased significantly with increasing treatment temperature. Even the samples that retained the biotite structure after heat treatment displayed some photocatalytic activity, suggesting that this method may also be suitable for preparing photocatalysts from other common natural materials.

Journal Articles

Photocatalytic unification of iodine species using platinum-loaded titanium dioxide

Sugita, Tsuyoshi; Mori, Masanobu*; Kozai, Naofumi

Journal of Photochemistry and Photobiology A; Chemistry, 438, p.114548_1 - 114548_6, 2023/04

 Times Cited Count:0 Percentile:0(Chemistry, Physical)

Removal of iodine from water contaminated by nuclear accidents or the release of radioactive waste is complicated and costly because iodine exists in a variety of forms in the water. We investigated the unification of iodine species by photocatalysis as a pretreatment for removing radioactive iodine species from water. The effect of the TiO$$_{2}$$ crystal phase of Pt-TiO$$_{2}$$ and solution pH on the photocatalytic redox reactions of iodide (I$$^{-}$$), iodate (IO$$_3^{-}$$), and $$o$$-iodobenzoic acid were evaluated. The choice of TiO$$_{2}$$ crystalline phase and pH allowed the mixture of iodine species to be unified to only I$$^{-}$$ or IO$$_3^{-}$$. Regardless of the type of Pt-TiO$$_{2}$$, the iodine in o-iodobenzoic acid was mineralized to I$$^{-}$$ under alkaline conditions. Because the iodine species can be unified to a single species by selecting the photocatalyst and the solution pH, this photocatalytic treatment could be applied to remove iodine species with high efficiency.

Journal Articles

Microscopic structural changes during the freeze cross-linking reaction in carboxymethyl cellulose nanofiber hydrogels

Miura, Daisuke*; Sekine, Yurina; Nankawa, Takuya; Sugita, Tsuyoshi; Oba, Yojiro; Hiroi, Kosuke; Ozawa, Tatsuhiko

Carbohydrate Polymer Technologies and Applications (Internet), 4, p.100251_1 - 100251_9, 2022/12

The reaction mechanism of carboxymethyl cellulose nanofiber (CMCF) hydrogel formed by freeze-crosslinking was investigated. We succeeded in observing the hierarchical structural changes during the freeze-crosslinking reaction. Freeze-crosslinked CMCF hydrogels exhibited a characteristic hierarchical alignment structure from the angstrom to micrometer scale that differed from normal cross-linked CMCF hydrogels produced by a conventional method without freezing. It was shown that the characteristic hierarchical structure contributes the excellent mechanical properties of freeze-crosslinked CMCF hydrogels.

Journal Articles

Urea-introduced ionic liquid for the effective extraction of Pt(IV) and Pd(II) ions

Ueda, Yuki; Eguchi, Ayano; Tokunaga, Kohei; Kikuchi, Kei*; Sugita, Tsuyoshi; Okamura, Hiroyuki; Naganawa, Hirochika

Industrial & Engineering Chemistry Research, 61(19), p.6640 - 6649, 2022/05

 Times Cited Count:0 Percentile:13.93(Engineering, Chemical)

no abstracts in English

Journal Articles

Carbonated nanohydroxyapatite from bone waste and its potential as a super adsorbent for removal of toxic ions

Sekine, Yurina; Nankawa, Takuya; Yamada, Teppei*; Matsumura, Daiju; Nemoto, Yoshihiro*; Takeguchi, Masaki*; Sugita, Tsuyoshi; Shimoyama, Iwao; Kozai, Naofumi; Morooka, Satoshi

Journal of Environmental Chemical Engineering, 9(2), p.105114_1 - 105114_12, 2021/04

 Times Cited Count:7 Percentile:50.7(Engineering, Environmental)

Remediating toxic ion contamination is crucial for protecting human health and the environment. This study aimed to provide a powerful strategy for effectively utilizing bone waste from the food production and preparation industries for removal of toxic ions. Here, we show that immersing pig bone in NaHCO$$_{3}$$ solution produced a carbonated nanohydroxyapatites (C-NHAP). The C-NHAP exhibited high adsorptivity for Sr$$^{2+}$$, Cd$$^{2+}$$, Pb$$^{2+}$$, and Cu$$^{2+}$$. The strontium adsorptivity was about 250 and 4,500 times higher than that of normal bone and synthetic HAP, respectively. The C-NHAP is an eco-friendly, high-performance material that is simple to prepare and should be useful for tackling problems of food waste disposal and environmental pollution.

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:30 Percentile:96.87(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

A Fluorous phosphate for the effective extraction of Ln$$^{III}$$ from nitrate media; Comparison with a conventional organic phosphate

Ueda, Yuki; Kikuchi, Kei*; Tokunaga, Kohei; Sugita, Tsuyoshi; Aoyagi, Noboru; Tanaka, Kazuya; Okamura, Hiroyuki

Solvent Extraction and Ion Exchange, 39(5-6), p.491 - 511, 2021/00

 Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Eco-friendly carboxymethyl cellulose nanofiber hydrogels prepared via freeze cross-linking and their applications

Sekine, Yurina; Nankawa, Takuya; Yunoki, Shunji*; Sugita, Tsuyoshi; Nakagawa, Hiroshi; Yamada, Teppei*

ACS Applied Polymer Materials (Internet), 2(12), p.5482 - 5491, 2020/12

 Times Cited Count:21 Percentile:86.3(Materials Science, Multidisciplinary)

We developed a cross-linking method using freeze concentration and used it to synthesize a new type of carboxymethyl cellulose nanofiber (CMCF) hydrogel with high compressive strength ($$>$$ 80 MPa) and high compressive recoverability. The hydrogels were prepared by adding an aqueous solution of citric acid (CA) to a frozen CMCF sol and then thawing the sol. The reaction between the freeze-concentrated CMCF and CA created a rigid porous structure that reflected the ice crystal structure. Their cross-linked structure has a high stability to compressive stress. Bentonite was immobilized on a CMCF hydrogel by adding bentonite to the CMCF sol before freeze cross-linking. The CMCF-bentonite hydrogel showed high adsorptivity for chemical dyes. The physically cross-linked CMCF hydrogels are non-toxic, metal-free, and simple to prepare, and thus they may be useful as sustainable materials in various fields.

Journal Articles

Development of evaluation method for photocatalytic ability by ion chromatography combined with a flow-type reactor; Application to immobilized photocatalyst materials prepared by double-layer coating method

Sugita, Tsuyoshi; Kobayashi, Kentaro*; Yamazaki, Taiki*; Isaka, Mayu*; Itabashi, Hideyuki*; Mori, Masanobu*

Journal of Photochemistry and Photobiology A; Chemistry, 400, p.112662_1 - 112662_8, 2020/09

 Times Cited Count:0 Percentile:2.6(Chemistry, Physical)

In this study, we developed an in-line photocatalytic performance evaluation system in which a flow reactor was connected to the ion chromatography to accurately evaluate the performance of the photocatalyst. This system was used to evaluate the photocatalyst supported by the two-layer support method on the substrate, such as glass beads. The performance of the photocatalyst was evaluated using dimethyl sulfoxide (DMSO), and it was possible to monitor the decomposition of DMSO by UV and the formation of by-products, such as methane sulfonate (MSO) and sulfate (SA). This system can be expected to be useful not only for evaluating the decomposition performance of an object using a photocatalyst but also for evaluating the byproducts.

Journal Articles

Extraction performance of a fluorous phosphate for Zr(IV) from HNO$$_{3}$$ solution; Comparison with tri-$$n$$-butyl phosphate

Ueda, Yuki; Kikuchi, Kei; Sugita, Tsuyoshi; Motokawa, Ryuhei

Solvent Extraction and Ion Exchange, 37(5), p.347 - 359, 2019/07

 Times Cited Count:8 Percentile:34.7(Chemistry, Multidisciplinary)

We have newly-designed fluorous phosphate(TFP) for the effective Zr(IV) ion extractant as an alternative extractant against the conventional organic phosphate, tri-$$n$$-butyl phosphate(TBP). Zr(IV) ion extraction system using the TBP has many problems such as the formation of the third phase during liquid-liquid extraction. Here, we develop the fluorous extraction system based on the TFP-perfluorohexane for the Zr(IV) ion extraction to improve the Zr(IV) ion extraction system with an effective extractability and without the third phase formation. Our main findings were that the significant high extraction performance of the TFP for Zr(IV) ion as compared with TBP, and the origins of the high extraction performance of the TFP are related to the water and HNO$$_{3}$$ contents in the fluorous phase and the stability of the complex, Zr(No$$_{3}$$)$$_{4}$$(TFP)$$_{3}$$.

Journal Articles

Evaluation of photocatalytic abilities by variation of conductivity and dimethyl sulfoxide; Photocatalytically active TiO$$_{2}$$-coated wire mesh prepared via a double-layer coating method

Mori, Masanobu*; Sugita, Tsuyoshi; Fujii, Kengo*; Yamazaki, Taiki*; Isaka, Mayu*; Kobayashi, Kentaro*; Iwamoto, Shinji*; Itabashi, Hideyuki*

Analytical Sciences, 34(12), p.1449 - 1453, 2018/12

 Times Cited Count:2 Percentile:7.2(Chemistry, Analytical)

The photocatalyst coating stainless-steel wire mesh (TiO$$_{2}$$-WM) was prepared by double-layer coating method. The TiO$$_{2}$$-WM was evaluated using flow analytical system, which included the reactor and conductimetric detector (FAS-CD). The DMSO decomposition test through the FAS-CD reveal that photocatalytst was stable coating on the stainless-steel wire mesh.

Journal Articles

Extraction ability of 4-benzoyl-3-phenyl-5-isoxazolone towards 4f-ions into ionic and molecular media

Atanassova, M.*; Okamura, Hiroyuki; Eguchi, Ayano; Ueda, Yuki; Sugita, Tsuyoshi; Shimojo, Kojiro

Analytical Sciences, 34(8), p.973 - 978, 2018/08

 Times Cited Count:17 Percentile:60.08(Chemistry, Analytical)

The distribution constants of 4-benzoyl-3-phenyl-5-isoxazolone (HPBI) and deprotonated one (PBI$$^{-}$$) between hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C$$_{1}$$C$$_{4}$$im][Tf$$_{2}$$N]) and aqueous phases were determined, together with the acid-dissociation constant of HPBI. The solvent extraction of three selected lanthanoid ions (La$$^{3+}$$, Eu$$^{3+}$$, and Lu$$^{3+}$$) with HPBI from aqueous nitrate phase into [C$$_{1}$$C$$_{4}$$im][Tf$$_{2}$$N] has been investigated. Application of the ionic liquid as the extracting phase greatly enhanced the extraction performance of HPBI for lanthanoid ions compared with that in the chloroform system. The composition of the extracted species was established to be anionic tetrakis entities, Ln(PBI)$$_{4}$$$$^{-}$$, for light, middle, and heavy lanthanoid ions in an ionic environment.

Journal Articles

A Fluorometric skin-interfaced microfluidic device and smartphone imaging module for ${{it in situ}}$ quantitative analysis of sweat chemistry

Sekine, Yurina; Kim, S. B.*; Zhang, Y.*; Bandodkar, A. J.*; Xu, S.*; Choi, J.*; Irie, Masahiro*; Ray, T. R.*; Kohli, P.*; Kozai, Naofumi; et al.

Lab on a Chip, 18(15), p.2178 - 2186, 2018/08

The rich composition of solutes and metabolites in sweat and its relative ease of collection upon excretion from skin pores make this class of biofluid an attractive candidate for point of care analysis. Here, we present a complementary approach that exploits fluorometric sensing modalities integrated into a soft, skin-interfaced microfluidic system which, when paired with a simple smartphone-based imaging module, allows for in-situ measurement of important biomarkers in sweat. A network array of microchannels and a collection of microreservoirs pre-filled with fluorescent probes that selectively react with target analytes in sweat (e.g. probes), enable quantitative, rapid analysis. Field studies on human subjects demonstrate the ability to measure the concentrations of chloride, sodium and zinc in sweat, with accuracy that matches that of conventional laboratory techniques.

Journal Articles

Enhanced aqueous adsorption and photodecomposition of anionic organic target by amino group-modified TiO$$_{2}$$ as anionic adsorptive photocatalyst

Sugita, Tsuyoshi; Kobayashi, Kenichi*; Kobayashi, Kentaro*; Yamazaki, Taiki*; Fujii, Kengo*; Itabashi, Hideyuki*; Mori, Masanobu*

Journal of Photochemistry and Photobiology A; Chemistry, 356, p.71 - 80, 2018/04

 Times Cited Count:5 Percentile:13.47(Chemistry, Physical)

Photocatalysts shows high redox property only by light irradiation. However, the reaction performance is lowered in aqueous phase due to the low contact efficiency between catalyst and targets. In this study, to enhance aqueous adsorption and photodecomposition of anionic organic target, we developed an amino functional-based spacer (3-[2-(2- aminoethylamino)ethylamino]propyl-trimethoxysilane, DETA), and used it to modify TiO$$_{2}$$. The modified catalyst with positively charged amino groups could enhance the adsorption and photodecomposition of anionic organic targets.

Journal Articles

A Comprehensive extraction study using a mono-alkylated diglycolamic acid extractant; Comparison between a secondary amide group and a tertiary amide group

Sugita, Tsuyoshi; Fujiwara, Iori*; Okamura, Hiroyuki; Oshima, Tatsuya*; Baba, Yoshinari*; Naganawa, Hirochika; Shimojo, Kojiro

Solvent Extraction Research and Development, Japan, 24(2), p.61 - 69, 2017/05

We investigated an influence of amide group in diglycolamic acid-type extractants on extraction property of metal ions. The extraction characteristics of $$N$$-dodecyldiglycolamic acid (C$$_{12}$$DGAA), with a secondary amide group, for 56 metal ions have been investigated, and compared with those of $$N,N$$-dioctyldiglycolamic acid (DODGAA) with a tertiary amide group. Compared with DODGAA, C$$_{12}$$DGAA has a poor extraction performance and separation ability for rare-earth metal ions, except for Sc(III). However, C$$_{12}$$DGAA tended to provide better extraction for relatively small-sized metal ions than DODGAA. In addition, it was found that C$$_{12}$$DGAA enables the selective removal of Hg(II) from aqueous solutions containing various divalent metal ions.

Journal Articles

Pretreatment method in FIA by solvent extraction and the application possibility of novel solvent extraction method

Sugita, Tsuyoshi

Journal of Flow Injection Analysis, 33(1), p.39 - 40, 2016/06

A novel solvent extraction way, emulsion flow (EF) method, has been developed at JAEA. EF method achieves both good emulsion formation and quick phase separation only by solution sending. In this report, I referred Flow Injection Analysis (FIA) using solvent extraction as a preprocessing technique and introduced an outline of the EF method as such. Furthermore, I mentioned the application possibility of the EF method to the preprocessing in FIA with its advantage for extracting and concentrating a trace component from a large-volume sample.

Journal Articles

Extraction behavior of rare-earth elements using a mono-alkylated diglycolamic acid extractant

Shimojo, Kojiro; Fujiwara, Iori*; Fujisawa, Kiyoshi*; Okamura, Hiroyuki; Sugita, Tsuyoshi; Oshima, Tatsuya*; Baba, Yoshinari*; Naganawa, Hirochika

Solvent Extraction Research and Development, Japan, 23(2), p.151 - 159, 2016/05

Liquid-liquid extraction of rare-earth (RE) cations has been investigated using $$N$$-dodecyldiglycolamic acid (C$$_{12}$$DGAA) with a secondary amide group, and compared with that using $$N,N$$-dioctyldiglycolamic acid (DODGAA) with a tertiary amide group. C$$_{12}$$DGAA enables quantitative transfer of all RE cations from moderately acidic solution, while being selective toward the heavier RE cations, and performs better than typical carboxylic-acid-type extractants. However, C$$_{12}$$DGAA provides low extraction performance and separation ability for RE cations compared with DODGAA because of the weaker basicity of the amide oxygen. Slope analysis demonstrated that RE$$^{3+}$$ transfer with C$$_{12}$$DGAA proceeded through a proton-exchange reaction, forming a 1:3 complex, RE(C$$_{12}$$DGAA)$$_{3}$$. Structural characterization by X-ray diffraction revealed that three $$N$$-butyldiglycolamic acid (C$$_{4}$$DGAA) molecules coordinated to the La$$^{3+}$$ central ion in a tridentate fashion and the La$$^{3+}$$ primary coordination sphere consisted of three oxygen atoms from the amide group, three oxygen atoms from the ether group, and three oxygen atoms from the carboxy group.

Journal Articles

Full-scale experimental study on mechanical behavior of a clay plug under HLW disposal conditions

Sasakura, Takeshi*; Masumoto, Kazuhiko*; Toida, Masaru*; Fujita, Tomoo; Sugita, Yutaka

Proceedings of 9th International Conference on Geo-environmental Engineering (GEE 2010), p.47 - 56, 2010/05

High level radioactive waste is to be vitrified, and after some period of storage for cooling, put into engineered barriers such as metal canister, overpack and buffer material, and finally disposed of in the stable geology at the depth of 300 m or deeper to isolate from human environment for a long period of time in Japan. The geological repository consists of surface facilities and subsurface facilities; the later, mainly consists of tunnels for transportation and waste emplacement, will be closed using sealing technologies such as backfilling, plugging, and grouting after emplacement of the waste to prevent seepage of radionuclides for a long period of time. Effectiveness of these sealing technologies, however, has not been well demonstrated in-situ worldwide, and the technologies may be considered in the stage of research and development. Therefore, in this paper, the in-situ tunnel sealing test performed at Canada to demonstrate the effectiveness of the plug under crystalline rock environment was overviewed focusing on the plug. Then behavior of the plug, particular of mechanical behavior, during sealing tests, observation result of dismantled plug were reviewed and points to be addressed for establishing the clay plug technology were identified. Because the procedure of this tunnel sealing test and hydraulic sealing performance of the plug has already been precisely reported by Fujita et al. (2007), outline of the test is briefly summarized and mechanical behavior of the plug was focused. As a result, effectiveness of conventional construction technology of a plug was shown, the behavior of a plug during the pressurization test was clarified and important points to be addressed for establishing the clay plug technology were identified.

62 (Records 1-20 displayed on this page)