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Separation of Micro-plastics from Sea Water Using Electromagnetic Archimedes Force
N. Nomura,F.Mishima,S.Nishijima 한국초전도저온학회 2023 한국초전도저온공학회논문지 Vol.25 No.3
Pollution of the environment by micro-plastics is now a worldwide problem. Plastics are difficult to decompose and put a greatload on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by oceancurrents over long distances, causing global pollution. These are not easily decomposed in the natural environment. In this paper,we aimed to experimentally demonstrate that micro-plastics in seawater can be continuously separated by electromagneticArchimedes force. Using polyethylene particles of 3 mm in diameter as the separation target, a flow channel was fabricated andseparation conditions were investigated by particle trajectory calculations for separation experiments. Based on the calculationresults, a solenoid-type superconducting magnet was used as a source of magnetic field to conduct separation experiments of micro-plastics in seawater. Although a high separation rate was assumed in the simulation results, the experimental results did not showany significant improvement in the separation rate due to the electromagnetic Archimedes force. It was found that the gas generatedby the electrolytic reaction may have inhibited the migration of the particles.
Magnetic separation device for paramagnetic materials operated in a low magnetic field
F. Mishima,N. Nomura,S. Nishijima 한국초전도저온학회 2022 한국초전도저온공학회논문지 Vol.24 No.3
We have been developing a magnetic separation device that can be used in low magnetic fields for paramagnetic materials. Magnetic separation of paramagnetic particles with a small particle size is desired for volume reduction of contaminated soil inFukushima or separation of iron scale from water supply system in power plants. However, the implementation of the system hasbeen difficult due to the needed magnetic fields is high for paramagnetic materials. This is because there was a problem in installingsuch a magnet in the site. Therefore, we have developed a magnetic separation system that combines a selection tube and magneticseparation that can separate small sized paramagnetic particles in a low magnetic field. The selection tube is a technique forclassifying the suspended particles by utilizing the phenomenon that the suspended particles come to rest when the gravity actingon the particles and the drag force are balanced when the suspension is flowed upward. In the balanced condition, they can becaptured with even small magnetic forces. In this study, we calculated the particle size of paramagnetic particles trapped in aselection tube in a high gradient magnetic field. As a result, the combination of the selection tube and HGMS (High GradientMagnetic Separation-system) can separate small sized paramagnetic particles under low magnetic field with high efficiency, andthis paper shows its potential application.
F. Mishima,Aoi Nagahama,N. Nomura,S. Nishijima 한국초전도저온학회 2023 한국초전도저온공학회논문지 Vol.25 No.3
Magnetic separation technology for small paramagnetic particles has been desired for the volume reduction of contaminated soil from the Fukushima nuclear power plant accident and for the separation of scale and crud from nuclear power plants. However, the magnetic separation for paramagnetic particles requires a superconducting high gradient magnetic separation system applied, hence expanding the bore diameter of the magnets is necessary for mass processing and the initial and running costs would be enormous. The use of high magnetic fields makes safe onsite operation difficult, and there is an industrial need to increase the magnetic separation efficiency for paramagnetic particles in as low a magnetic field as possible. Therefore, we have been developing a magnetic separation system combined with a selection tube, which can separate small paramagnetic particles in a low magnetic field. In the previous technique we developed, a certain range of particle size was classified, and the classified particles were captured by magnetic separation. In this new approach, the fluid control method has been improved in order to the selectively classify particles of various diameters by using a multi-stage selection tube. The soil classification using a multi-stage selection tube was studied by calculation and experiment, and good results were obtained. In this paper, we report the effectiveness of the multi-stage selection tube was examined.
ALUMINA POWDER PREPARED BY THE HYDROLYSIS OF AL-PROPOXIDE IN THE SUPERCRITICAL FLUID OF PROPANOL
Nakagawa, Nakagawa, Z.,Enomoto, Enomoto, N.,Nomura, Nomura, S.,Kim, Kim, D.W.,Lim, Lim, D.Y. 한국재료학회 1995 Fabrication and Characterization of Advanced Mater Vol.2 No.4
Al-isopropoxide dispersed into isopropanol was heated in an autoclave above the critical point of propanol(23$5^{\circ}C$, 4.7MPa). Propanol coexisting Al-isopropoxide produced some water during the condensation reaction to isopropul ether, while only propanol did not change under that conditions. This water hydrolyzed Al-isopropoxide to form an alumina at 30$5^{\circ}C$ and 11.0MPa. This alumina had a similar X-ray diffraction pattern of $\chi$-alumina. The heating treatment showed the aluminal transformed directly to ${\alpha}$-alumina around 110$0^{\circ}C$, not to pass via any other intermediate aluminas. The aluminal was named pseudo $\chi$-alumina as a new phase. As-prepared alumina was fine powder of about 20nm, and had about 5% weight loss in the temperature range from 30$0^{\circ}C$ to 65$0^{\circ}C$, and the IR spectral showed no constitutional water.
Rogozin, E. A.,Lee, K. W.,Kang, N. J.,Yu, H.,Nomura, M.,Miyamoto, K.-I.,Conney, A. H.,Bode, A. M.,Dong, Z. Oxford University Press 2008 Carcinogenesis Vol.29 No.6
<P>Some xanthine analogues, including 1,3,7-trimethylxanthine (caffeine) and 1,3-dimethylxanthine (theophylline), have been shown to exert anticancer activities in both cell culture and animal models. The present study focused on the relationship of structure and activity of 50 different caffeine analogues in preventing epidermal growth factor (EGF)-induced malignant transformation of mouse epidermal JB6 promotion-sensitive (P+) Cl41 (JB6 P+) cells. Results indicated that the inhibition of cell transformation by the 1,3,7-trialkylxanthines depends on the number of carbons at the alkyl groups R1 and R3, but not R7. Notably, 1-ethyl-3-hexylxanthine (xanthine 70) was the most effective compound for inhibiting EGF-induced neoplastic transformation among the 50 xanthine analogues tested. The 50% inhibition of cell transformation (ICT(50)) value for xanthine 70 was 48- or 75-fold less than the ICT(50) value of caffeine or theophylline, respectively. Further study revealed that xanthine 70 (5-40 muM) dose dependently inhibited EGF-induced transactivation of activator protein 1 (AP-1), whereas theophylline or caffeine (up to 500 muM) had no effect on AP-1 activity. In addition, xanthine 70 (10 muM) inhibited 12-O-tetradecanoylphorbol-13-acetate- or H-Ras-induced neoplastic transformation in JB6 P+ cells by 78.2 or 62.0%, respectively. Collectively, these results indicated that the number of carbons at R1 and R3 is important for the antitumor-promoting activity of the trialkylxanthines and xanthine 70 might be a promising anticancer agent.</P>