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73.
Masakoto Kanezashi Akira Yamamoto Tomohisa Yoshioka Toshinori Tsuru 《American Institute of Chemical Engineers》2010,56(5):1204-1212
A sol–gel method was applied for the preparation of silica membranes with different average pore sizes. Ammonia (NH3) permeation/separation characteristics of the silica membranes were examined in a wide temperature range (50–400°C) by measurement of both single and binary component separation. The order of gas permeance through the silica membranes, which was independent of membrane average pore size, was as follows: He > H2 > NH3 > N2. These results suggest that, for permeation through silica membranes, the molecular size of NH3 is larger than that of H2, despite previous reports that the kinetic diameter of NH3 is smaller than that of H2. At high temperatures, there was no effect of NH3 adsorption on H2 permeation characteristics, and silica membranes were highly stable in NH3 at 400°C (i.e., gas permeance remained unchanged). On the other hand, at 50°C NH3 molecules adsorbed on the silica improved NH3‐permselectivity by blocking permeation of H2 molecules without decreasing NH3 permeance. The maximal NH3/H2 permeance ratio obtained during binary component separation was ~30 with an NH3 permeance of ~10?7 mol m?2 s?1 Pa?1 at an H2 permeation activation energy of ~6 kJ mol?1. © 2009 American Institute of Chemical Engineers AIChE J, 2010 相似文献
74.
Pore‐size evaluation and gas transport behaviors of microporous membranes: An experimental and theoretical study 下载免费PDF全文
Gang Li Hye Ryeon Lee Hiroki Nagasawa Masakoto Kanezashi Tomohisa Yoshioka Toshinori Tsuru 《American Institute of Chemical Engineers》2015,61(7):2268-2279
A modified gas‐translation (GT) model based on a GT mechanism was successfully applied to the pore‐size evaluation and gas transport behavior analysis of microporous membranes with different pore‐size distributions. Based on the gas permeation results of three microporous membranes derived from different alkoxides, the effects of activation energy and the selection of a standard gas on the pore‐size evaluation were discussed in a comparative study. The presence of nano‐sized defects had an important influence on the gas permeation performance of microporous membranes, depending largely on the original pore size of the membrane in question. Moreover, the gas‐separation effect of the pore‐size distribution in a silica membrane was theoretically studied and revealed a significant increase in gas permeance for relatively large gas species but not for small ones. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2268–2279, 2015 相似文献
75.
Gas permeability of thin dense films from polymer blend of thermoplastic elastomer and polyolefin 下载免费PDF全文
Masamoto Uenishi Noriaki Fukushima Masashi Teramachi Masahiko Mizuta Jun Kamo Toshinori Tsuru 《应用聚合物科学杂志》2014,131(1)
Stretched thin films composed of a thermoplastic elastomer, a polystyrene‐block‐poly(ethylene butylene)‐block‐polystyrene triblock copolymer (SEBS), and polyolefins, poly(ethylene‐co‐ethylacrylate) and poly(ethylene‐co‐propylene), were obtained by blow‐molding, uniaxial stretching, and cooling to room temperature and the gas permeability of the stretched films was investigated. When the as‐blown annealed film was subjected to uniaxial stretching in the machine direction, PO2 and PN2 increased with an increase in the stretching ratio K and approached a constant value at high stretching ratios. In addition, PO2/PN2 decreased gradually with K and approached a value of 2.95–3.0. The reason for this unique gas permeation behavior is that the molecular mobility of poly(ethylene butylene) chains in a direction normal to the film increases and reaches an equilibrium state at around K = 4.5. The change in gas permeability of the stretched films can be explained using a deformation model for the SEBS matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39386. 相似文献
76.
Toshiaki Yoshioka Tomohito Kameda Guido Grause Shogo Imai Akitsugu Okuwaki 《Journal of Polymer Research》2010,17(4):489-493
In this study, the use of diethylene glycol (DEG), triethylene glycol (TEG), n-C10H21OH, and ethylene glycol (EG) as solvents for NaOH in the dechlorination of poly(vinyl chloride) (PVC) was investigated. In
the early reaction time, the degrees of dechlorination for DEG, TEG, and n-C10H21OH were notably higher than that for EG. Further, the high compatibility between PVC and the solvents was considered to result
in the easy penetration of the solvent and OH− into PVC particles, leading to the acceleration of dechlorination in the early reaction stage. An improvement of the dechlorination
was actually observed for DEG and TEG compared with EG. The solvent with the best compatibility to PVC, n-C10H21OH, however, showed little improvement due to the formation of a protective polyene layer on the surface of the PVC particles. 相似文献
77.
Different sizes of zeolite nanocrystals were fabricated from zeolite microparticles using a centrifugation-assisted grinding method. The zeolite nanocrystal formation can be attributed to the Al2O3 bowl mill generation of mechanical stress that fractured zeolite microparticles into smaller fragments. In the present study, the smaller fragments had a wide distribution of size and morphology. Therefore, different sizes of zeolite nanocrystals could be recovered from these smaller fragments by varying the centrifugation process. Zeolite nanocrystal product yields were measured by periodically recovering the nanocrystals from the smaller fragments based on milled zeolite powder. The larger crystals of zeolite were typically irregular in shape, whereas the smaller zeolite nanocrystals tended to be spherical. High product yield of the zeolite nanocrystals was obtained by periodically removing nanocrystals from the milled zeolite powder and recycling the large zeolite particles. Thus, the results from this new hybrid process suggest that it can be used to fabricate differing sizes of zeolite nanocrystals. In addition, the size of the recovered zeolite nanocrystal products was narrow, and the initial zeolite nanocrystal structure was not destroyed by the mechanical stress. 相似文献
78.
Gang Li Masakoto KanezashiHye Ryeon Lee Makoto MaedaTomohisa Yoshioka Toshinori Tsuru 《International Journal of Hydrogen Energy》2012
A novel bimodal catalytic membrane reactor (BCMR) consisting of a Ru/γ-Al2O3/α-Al2O3 bimodal catalytic support and a silica separation layer was proposed. The catalytic activity of the support was successfully improved due to enhanced Ru dispersion by the increased specific surface area for the γ-Al2O3/α-Al2O3 bimodal structure. The silica separation layer was prepared via a sol–gel process, showing a H2 permeance of 2.6 × 10−7 mol Pa−1 m−2 s−1, with H2/NH3 and H2/N2 permeance ratios of 120 and 180 at 500 °C. The BCMR was applied to NH3 decomposition for COx-free hydrogen production. When the reaction was carried out with a NH3 feed flow rate of 40 ml min−1 at 450 °C and the reaction pressure was increased from 0.1 to 0.3 MPa, NH3 conversion decreased from 50.8 to 35.5% without H2 extraction mainly due to the increased H2 inhibition effect. With H2 extraction, however, NH3 conversion increased from 68.8 to 74.4% due to the enhanced driving force for H2 permeation through the membrane. 相似文献
79.
Hirose Hideo Hikita Masayuki Ohtsuka Shinya Tsuru Shin-ichirou Ichimaru Junji 《Dielectrics and Electrical Insulation, IEEE Transactions on》2008,15(5):1252-1260
To diagnose the electric power apparatus, the decision tree method can be a highly recommended classification tool because it provides the if-then-rule in visible, and thus we may have a possibility to connect the physical phenomena to the observed signals. The most important point in constructing the diagnosing system is to make clear the relations between the faults and the corresponding signals. Such a database system can be built up in the laboratory using a model electric power apparatus, and we have made it. The next important thing is the feature extraction. We used ø - V - n patterns and POW patterns for feature variables, and feature extraction is made by the extended moments, usual moments, and the parameters in the underlying distributions such as the generalized normal distribution and the Weibull distribution. By simple arrangements, we will be able to classify the faults and noise with high accuracy such that the misclassification rate is lower than 5%. If we set appropriate pre-processing procedure carefully, we might have a possibility of classification accuracy of less than 2%. Therefore, the decision tree with adequate feature extraction is considered to be a promising method as one of the classification tools 相似文献
80.
Tokuhiro Ogura Hideho Takada Masashi Okuno Hiroaki Kitade Takashi Matsuura Masanori Kwon Seizaburo Arita Kei Hamazaki Miho Itomura Tomohito Hamazaki 《Lipids》2010,45(2):137-144
The composition of fatty acids in abdominal subcutaneous adipose tissue and the correlation of fatty acid values of plasma
and erythrocytes had not been reported in Japan. The aim of the present study was to investigate the fatty acid composition
and correlation of plasma and erythrocyte phospholipids (PL) and adipose triacylglycerols (TG) in 75 adult patients admitted
for non-malignant diseases. We also examined the relationship of n-3 and n-6 polyunsaturated fatty acid (PUFA) with patients’
characteristics. The total n-3 PUFA were 11.2, 11.8 and 1.9%, and the ratios of n-6/n-3 were 2.41, 1.87 and 8.20 in plasma
and erythrocyte PL and adipose TG, respectively. There were the highest correlations for total n-3 PUFA and the n-6/n-3 ratio
between plasma and erythrocyte PL and adipose TG. There was a positive correlation between n-3 PUFAs and age, but a negative
correlation was found between n-6 PUFAs and age. There was no significant difference in the values of PUFAs in plasma and
erythrocyte PL and adipose TG between men and women. The patients with cholesterol cholecystolithiasis showed a significantly
lower proportion of eicosapentaenoic acid in plasma and erythrocyte PL than those of the other patients. Our findings suggest
that PUFA in plasma and erythrocyte PL may be good biomarkers and more acceptable for studying participants than adipose TG. 相似文献