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Masuki, Yuma*; Katsuta, Nagayoshi*; Naito, Sayuri*; Murakami, Takuma*; Umemura, Ayako*; Fujita, Natsuko; Matsubara, Akihiro*; Minami, Masayo*; Niwa, Masakazu; Yoshida, Hidekazu*; et al.
Journal of Hazardous Materials, 485, p.136843_1 - 136843_10, 2025/03
Times Cited Count：0 Percentile：0.00(Engineering, Environmental)Lacustrine deposits have 30-fold higher As abundance than the average crustal deposit. Arsenic is mostly concentrated as discrete horizons deposited in spring and autumn. As-rich layers contain FeAsS, AsS, and As
S
but As-rich hotspots mostly contain FeAsS. As accumulation to sediment is controlled by redox potential with organic matter.
Lee, C.*; Matsuoka, Toshiyuki; Ishigaki, Koichi; Tanoue, Masayoshi*; Narita, Norifumi*; Kojima, Masakazu*; Tsuchiya, Terumitsu*; Matsuoka, Toshifumi*
Proceedings of 10th International Symposium on Recent Advances in Exploration Geophysics (RAEG 2006), p.143 - 146, 2006/00
It is known that 3-D Vertical Seismic Profile (VSP) method has an advantage on imaging the fault and fracture zone near the borehole, especially steeply dipped structure. Cosma et al (2003) has developed the new technique named Image Point Transform (IP Transform) and applied to offset VSP data to improve the week reflection signals from the steeply dipped fracture. We test the applicability of this method to the 3-D Reverse VSP data of numerical simulation and develop the method of imaging named spectral operator of middle point of IP. In the results of applying to 3-D model of steeply dipped fracture, we know that this method is applicable to 3-D reverse VSP data and could get the good image of fracture reconstructed by spectral operator of middle point of IP.
Hirota, Koichi; Sakai, Hiroki*; Washio, Masakazu*; Kojima, Takuji
Industrial & Engineering Chemistry Research, 43(5), p.1185 - 1191, 2004/03
Times Cited Count：49 Percentile：79.89(Engineering, Chemical)Twenty volatile organic compounds (VOCs) were irradiated with electron beams in laboratory scale to obtain an electron-beam energy required for a 90% treatment. The experiments showed that the energy was related with the chemical structure and roughly estimated from rate constants for reactions with OH radicals. The cost analysis revealed that the unification of a self-shielding electron accelerator with a reactor could reduce the capital cost for an electron-beam system. Electron-beam technology is a promising method for the treatment of VOCs.
; Neutron diffraction and scattering studyNakamura, Hiroyuki*; Yamasaki, Tomoaki*; Giri, S.*; Imai, Hideto*; Shiga, Masayuki*; Kojima, Kenji*; Nishi, Masakazu*; Kakurai, Kazuhisa*; Metoki, Naoto
Journal of the Physical Society of Japan, 69(9), p.2763 - 2766, 2000/09
Times Cited Count：61 Percentile：86.67(Physics, Multidisciplinary)no abstracts in English
Hayakawa, Kosetsu*; Muraguchi, Masakazu*; Masebo, Yumeno*; Kojima, Yoichiro*; Oda, Masato*; Yabuta, Rina*; Ishii, Hiroyuki*; Honda, Mitsunori
no journal, ,
Weathered biotite (WB), a layered clay mineral, has shown thermoelectric properties at temperatures above 700
C after molten salt treatment. Composed of environmentally friendly elements such as Si, Al, Fe, and Mg, WB is a promising thermoelectric material. This study focuses on the intercalation of Cs and Sr ions into WB during molten salt treatment and investigates the resulting structural and electrical changes. XRF confirmed the incorporation of Cs and Sr along with WB's main elements. XRD revealed that the layered structure of WB was preserved, showing characteristic peaks around 9 and 27. XAFS analysis at the Fe K-edge identified oxygen and silicon as the first and second nearest neighbors, respectively. As the Sr content increased, the intensity of the Si-related peak decreased, suggesting that Cs initially bonds with Si, while Sr forms bonds predominantly with oxygen. These structural changes influence the electrical conductivity of WB, highlighting the relationship between ion intercalation, structural modification, and thermoelectric properties.
Hayakawa, Kosetsu*; Masebo, Yumeno*; Muraguchi, Masakazu*; Kojima, Yoichiro*; Oda, Masato*; Iino, Chiaki*; Ishii, Hiroyuki*; Honda, Mitsunori
no journal, ,
We have been studying the development of functional materials derived from WB as an application of molten-salt treatment technology. We have experimentally demonstrated that Sr can be adsorbed on the interlayer of WB by molten-salt treatment. However, the correlation between Cs adsorption and Sr adsorption has not yet been clarified, although Sr adsorption was examined for Cs adsorbed WB in a previous study. Therefore, in this study, the amount and structure of Sr adsorption with and without Cs adsorption were investigated using XRF, XRD and XAFS. The results showed that the Sr adsorption dependence may differ depending on the presence or absence of Cs in WB.
Hayakawa, Kosetsu*; Masebo, Yumeno*; Muraguchi, Masakazu*; Kojima, Yoichiro*; Oda, Masato*; Yabuta, Rina*; Ishii, Hiroyuki*; Honda, Mitsunori
no journal, ,
With thermoelectric power generation technology attracting attention as a technology for effective utilization of waste heat to realize a low-carbon society, we have focused on weathered biotite (WB), one of the soil clay minerals with potential as a new thermoelectric material, and have synthesized various crystal minerals using the molten-salt method. As a result, we have clarified two processes by applying the molten salt method: intercalation, in which alkali ions are adsorbed between the layers while the layer structure of WB is maintained; and destruction and reconstruction of the layer structure to form new crystalline minerals, The WB was successfully used to create thermoelectric materials. In this study, the influence of Sr intercalation with SrCl in the molten salt on the structure and thermoelectric properties was investigated: samples were prepared with three different SrCl additions (1x, 5x and 10x) to the WB mass and analyzed by XRF, XRD and XAFS. The results of the composition analysis by XRF showed that the Sr adsorption increased to 12.7% (1x), 16.5% (5x) and 23.4% (10x) according to the addition amount. XAFS measurements were carried out under five conditions (room temperature, 300C, 500C, 700C and room temperature after cooling) in order to clarify the Sr local structure of the WB. The first coordination (P1) Sr-O and second coordination (P2) Sr-Si were identified in the obtained radial structure functions, and the P1 peak showed an increasing trend with increasing temperature.
Hayakawa, Kosetsu; Masebo, Yumeno*; Muraguchi, Masakazu*; Kojima, Yoichiro*; Oda, Masato*; Iino, Chiaki*; Ishii, Hiroyuki*; Honda, Mitsunori
no journal, ,
Soil clay minerals are expected to be a new thermoelectric material in the high temperature range, but the mechanism of their thermoelectricity has not been clarified yet. We have focused on weathered biotite (WB), a soil clay mineral composed of elements such as Si, Fe, Al, Mg, and K. We have found that the structure of WB changes under high temperature conditions, which can be observed by infrared absorption spectroscopy. In-situ observation by infrared absorption spectroscopy has shown that the structure of WB changes under high temperature conditions. However, the detailed structure has not yet been identified. In this study, we developed a method for synchrotron XAFS analysis of WB at high temperatures, where thermoelectric properties are observed, and succeeded in obtaining data from room temperature up to 873K.
