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71.
An experimental study was carried out to develop a new type of two-way diffuser suitable for a fluid flow energy conversion system. It is known that the power available from the fluid flow is proportional to the cube of the free stream velocity of the flow. Therefore, in order to take higher power output from the fluid flow, it is very important to construct a suitable system to increase the flow velocity. For a wind turbine, it has been reported that the speed of wind passing through it is dramatically increased by the use of a diffuser with a brim around the turbine. In this study, a new type of two-way diffuser suitable for a flow periodically changing its direction, such as a tidal current, was developed, applying the system to accelerate the wind speed for the wind turbine. The effects of the brim height and the outside body shape on the diffuser performance were experimentally investigated by measurement of the pressure and the velocity distributions along the center axis of the diffuser and around the diffuser. The present study is the first one to clarify the effect of these on diffuser performance. 相似文献
72.
Escobin-Mopera L Ohtani M Sekiguchi S Sone T Abe A Tanaka M Meevootisom V Asano K 《Journal of Bioscience and Bioengineering》2012,113(5):562-567
Phytase, an enzyme that catalyzes the hydrolysis of phytate, was purified from Klebsiella pneumoniae 9-3B. The isolate was preferentially selected in a medium which contains phytate as a sole carbon and phosphate source. Phytic acid was utilized for growth and consequently stimulated phytase production. Phytase production was detected throughout growth and the highest phytase production was observed at the onset of stationary phase. The purification scheme including ion exchange chromatography and gel filtration resulted in a 240 and 2077 fold purification of the enzyme with 2% and 15% recovery of the total activity for liberation of inorganic phosphate and inositol, respectively. The purified phytase was a monomeric protein with an estimated molecular weight of 45kDa based on size exclusion chromatography and SDS-PAGE analyses. The phytase has an optimum pH of 4.0 and optimum temperature of 50°C. The phytase activity was slightly stimulated by Ca(2+) and EDTA and inhibited by Zn(2+) and Fe(2+). The phytase exhibited broad substrate specificity and the K(m) value for phytate was 0.04mM. The enzyme completely hydrolyzed myo-inositol hexakisphosphate (phytate) to myo-inositol and inorganic phosphate. The properties of the enzyme prove that it is a good candidate for the hydrolysis of phytate for industrial applications. 相似文献
73.
M. Matsumoto M. Shiomi K. Osakada F. Abe 《International Journal of Machine Tools and Manufacture》2002,42(1)
A method for calculating the distribution of temperature and stress within a single metallic layer formed on the powder bed in rapid prototyping with the selective laser melting method is proposed. The solidified layer is assumed to be subjected to plane-stress deformation and the two-dimensional finite element methods for heat conduction and elastic deformation are combined. In the simulation, the finite element mesh is constructed on the surface of the powder bed. The heat caused by laser irradiation is given to the elements under the laser beam. Shrinkage due to solidification is assumed to result in only the change of the layer thickness. In the elastic finite element simulation, the Young's modulus of the solidified part is expressed as a function of temperature. To simplify the calculation, the whole area is treated to be continuous, and the powder bed and the molten part are assumed to have a very small Young's modulus. The heat conduction and the elastic finite element calculations are carried out alternately. The obtained results of deformation and tensile stress distribution show the possibility and places of cracking of the layer during forming. 相似文献
74.
Katsuhiko Takenaka Satomi Kawamoto Masamitsu Miya Hiroki Takeshita Tomoo Shiomi 《Polymer International》2010,59(7):891-895
The presence of a bulky substituent at the 2‐position of 1,3‐butadiene derivatives is known to affect the polymerization behavior and microstructure of the resulting polymers. Free‐radical polymerization of 2‐triethoxysilyl‐1,3‐butadiene ( 1 ) was carried out under various conditions, and its polymerization behavior was compared with that of 2‐triethoxymethyl‐ and other silyl‐substituted butadienes. A sticky polymer of high 1,4‐structure ( ) was obtained in moderate yield by 2,2′‐azobisisobutyronitrile (AIBN)‐initiated polymerization. A smaller amount of Diels–Alder dimer was formed compared with the case of other silyl‐substituted butadienes. The rate of polymerization (Rp) was found to be Rp = k[AIBN]0.5[ 1 ]1.2, and the overall activation energy for polymerization was determined to be 117 kJ mol?1. The monomer reactivity ratios in copolymerization with styrene were r 1 = 2.65 and rst = 0.26. The glass transition temperature of the polymer of 1 was found to be ?78 °C. Free‐radical polymerization of 1 proceeded smoothly to give the corresponding 1,4‐polydiene. The 1,4‐E content of the polymer was less compared with that of poly(2‐triethoxymethyl‐1,3‐butadiene) and poly(2‐triisopropoxysilyl‐1,3‐butadiene) prepared under similar conditions. Copyright © 2010 Society of Chemical Industry 相似文献
75.
76.
77.
Dynamic recrystallization behaviour of copper isoaxial bicrystals with various 〈001〉 tilt boundaries was investigated at 1023
and 1073 K at an initial strain rate of 3.33×10−4sec−1, with special attention paid to the effect of grain boundaries on the recrystallization stress (strain) and the substructure
developed during deformation. The grain boundaries in the bicrystals have almost no effect on the stress-strain curves. Flow
stress was found to fall abruptly and significantly during deformation, being similar to the flow stress in the single crystals.
The stressσ
R (ɛ
R), just before the stress fall indicates the stress (strain) at which dynamic recrystallization occurs. The growth of recrystallized
grains is markedly fast in these bicrystals, suggesting that dynamic recrystallization is controlled by a nucleation process.
The value ofσ
R in bicrystals with a tilt boundary of 9°,θ9 bicrystals, is almost equal to that in single crystals, but is larger thanσ
R inθ23,θ36 andθ43 bicrystals. These results indicate that theθ9 boundary has no effect on the dynamic recrystallization of bicrystals, whereas grain boundaries with tilt angles above 23°
accelerate the dynamic recrystallization of these bicrystals. Theθ-dependence ofσ
R orɛ
R is discussed in connection with the stress concentration near the grain boundary. 相似文献
78.
Phthoxazolin A is a new inhibitor of cellulose biosynthesis produces by Streptomyces sp. OM-5714. The active compound was isolated, and the structure was elucidated by spectrometric analyses. 相似文献
79.
Yoichi Shiomi Hiroaki Kutsuna Koji Akagawa Mamoru Ozawa 《Nuclear Engineering and Design》1993,141(1-2)
The two-phase flow pattern in a concentric annulus with a rotating inner cylinder have been investigated experimentally. The observed flow patterns were dispersed bubbly, ring-form, single-spiral, double-spiral, triple-spiral flows and transition regions. When the rotational speed was at a relatively low level, the buoyancy effect of bubbles dominated the flow field and a dispersed bubbly flow was formed. On the other hand, when the rotational speed was at a high level, the vortex motion induced by the rotation dominated the flow field and ring-form and spiral flows were formed. 相似文献
80.
Kiyokazu Imai Tomoo Shiomi Yasuyuki Tezuka Hiroko Itamochi Masamitsu Miya 《应用聚合物科学杂志》1993,48(9):1525-1529
Separability of SO2 from mixtures of SO2 and N2 gases was studied for membranes of poly(vinyl alcohol) (PVA) and cellulose modified with methyl, ethyl, t-butyl, and phenyl vinyl sulfoxides. Of these sulfoxide-modified polymers, the phenyl vinyl sulfoxide-modified PVA membranes were found to give the best separation of SO2. In the phenyl vinyl sulfoxide modified PVA membranes, the permeability coefficient of SO2 increased with sulfoxide content while separability of SO2 was maximum at a sulfoxide content of 23.5 mol %; the separation factor of SO2 was about 170 at this sulfoxide content. © 1993 John Wiley & Sons, Inc. 相似文献