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1.
Presently, many wind turbine generators (WTGs) are connected to the power grid. While the penetration of wind power to the power system is increasing, FIT price is decreasing. Therefore, wind generation companies want to increase the electric power output from wind farms (WFs). In this article, we propose a control technique to reduce the influence of the wake by changing a power coefficient of each WTG in a WF for the purpose of improving electric power output of WFs. We showed the optimization technique of a power coefficient of each WTG and the effect of reducing the influence of the wake using measurement data from WFs. In addition, we formulated the wake effect as a function of distance between WTGs. We verified 1% improvement of generated energy in a year compared to the conventional control method by simulation. Furthermore, we quantified the improvement of generated energy output, using the distance between WTGs and the occurrence rate of the direction of the wind as a variable. 相似文献
2.
John McGrady Shinichi Yamashita Atsushi Kimura Sho Kano Huilong Yang Zhengang Duan 《Journal of Nuclear Science and Technology》2020,57(4):463-471
ABSTRACTTypical metal oxide corrosion products of structural materials have been irradiated with γ-rays in ultra-pure water to investigate the effect of radiation on the surface oxide and the nature of adsorbed water. Analysis techniques including thermal gravimetric analysis, differential thermal analysis, diffuse reflectance infrared Fourier transform spectroscopy, and X-ray photoelectron spectroscopy before and after γ-irradiation were employed to investigate surface structural effects and adsorbed water behaviour. The production of H2 in the oxide nanoparticle mixtures was investigated by gas chromatography to probe the mechanism of radiolysis in the water/oxide mixtures and the relationship with surface water. The nature of water at the surface of the oxides was affected by γ-radiation and the relationship was dependent on the particle composition. The rate of H2 production was shown to be oxide dependent, and higher rates of H2 formation were attributed to the decomposition of surface adsorbed water. Changes to the surface chemistry and H2 production rates were found to be highly dependent on the surface chemistry of the metal oxide nanoparticle and no bulk structural changes were observed. 相似文献
3.
Talc-containing polypropylene (PP) resin is extensively employed in automobiles. Herein, considering the microstructure transfer process in injection molding, the effect of the talc's dispersibility and particle size on this process and its impact on the gloss level of the product were investigated. Results show that a fine unevenness of about several micrometers was self-formed by the shrinkage of PP in nontransferred areas due to the blending of talc. Additionally, the amount of self-formed unevenness tended with an increase in the average particle size of talc. Furthermore, due to PP shrinkage and different densities of talc, it was observed that a fine tiger-stripe pattern was self-formed using special molds with modified microstructure. This self-formed fine unevenness changes the gloss level owing to the diffused light reflection effect. This study proposes controlling this change by controlling the average particle size of talc and structure of the mold. POLYM. ENG. SCI., 60:132–139, 2020. © 2019 Society of Plastics Engineers 相似文献
4.
Koji Morita Byung-Nam Kim Hidehiro Yoshida Keijiro Hiraga Yoshio Sakka 《Journal of the European Ceramic Society》2018,38(6):2588-2595
Carbon contamination from the carbon paper/dies during spark-plasma-sintering (SPS) processing was examined in the MgAl2O4 spinel. The carbon contamination sensitively changes with the heating rate during the SPS processing. At the high heating rate of 100 °C/min, the carbon contamination having organized structures occurred over almost the entire area from the surface to deep inside the SPSed spinel disk. In contrast, at the slow heating rate of 10 °C/min, the carbon contamination having disordered structures occurred only around the surface area. The carbon phases transform into high pressure CO/CO2 gases by post-annealing in air and lead to pore formation along the grain junctions. The pore formation significantly occurs at the high heating rate due to the large amount of the contaminant carbon phases. This suggests that if once the carbon contamination was formed in the materials, it is very difficult to remove the carbon phases from the materials. 相似文献
5.
Dalia Heggo Shinichi Ookawara Teruhisa Ohno Toru Nakai Yoshihisa Matsushita Mona Gamal Eldin Masahiro Ohshima 《加拿大化工杂志》2020,98(1):119-126
Dense photocatalyst slurry was employed for the synthesis of p-anisaldehyde under solar light irradiation. An Fe-modified rutile TiO 2 (Fe-TiO 2, 34.5 m 2/g) photocatalyst was used as a visible-light-responsive photocatalyst. A conventional TiO 2 (P25, 35 m 2/g) photocatalyst was also examined as a reference catalyst. XRD patterns and diffuse reflectance spectra showed that Fe-TiO 2 consists of 100 % rutile phase and absorbs more visible light compared to P25, respectively. The catalyst powder was suspended in an ethyl acetate solution of p-methoxytoluene in the mini-reactor, with oxygen bubbling, under a solar simulator, visible light, and UV LEDs. p-anisaldehyde, as a reaction product, was analyzed by sampling using gas-chromatograph. Regardless of the light source, Fe-TiO 2 always outperformed P25 in terms of both generation rates (GR) of p-anisaldehyde and energy requirements (ER). It was demonstrated that the highly dense Fe-TiO 2 slurry was efficient for the synthesis under solar light owing to the small size of the reactor. The small amount of Pt and ZrO 2 cocatalysts significantly enhanced the GR under solar light. By adopting a visible light responsive Fe-TiO 2 photocatalyst, the mini slurry-bubble reactor under solar light achieved a high GR per catalyst mass (CM), which is one to two orders higher than that reported by most previous studies with high-power lamps. 相似文献
6.
Francis Njoka Shinichi Ookawara Mahmoud Ahmed 《International Journal of Hydrogen Energy》2018,43(3):1285-1302
Solar-driven photoelectrochemical water splitting technology is a promising avenue for a sustainable hydrogen production. In this work, a comprehensive 2-dimensional model is developed and numerically simulated with hematite (α-Fe2O3) as the principal photoelectrode. The model evaluates light absorption, charge transport and electrochemical reactions to elucidate the effects of light transmitting materials, electrolyte height and electrolyte velocity on hydrogen and oxygen gas production. Results indicated that major losses in photocurrents are attributed to the transparent conducting oxide while losses due to the electrolyte increase with its height. Gas concentrations increase with increasing photocurrent densities and also in the direction of the flow. Gas bubbles however decrease with increasing electrolyte velocity. From these results, light reception in the reactor is uneven and poses a bigger challenge due to the bias in gas bubble distribution. Prospects of upscaling tandem schemes hence not only lie in the semiconductor material combinations but rather in the proper integration of system components and operating conditions. 相似文献
7.
An ultrasonic treatment system, using a TiO2 photocatalyst, was used to disinfect Legionella pneumophila. A kinetic study of the process indicates that TiO2 significantly improves the disinfection process. The concentrations of viable cells were reduced to 6% of the initial concentrations in the presence of 0.2 g/ml TiO2 after a 30 min of treatment period, while only an 18% reduction was observed in the absence of TiO2. The potency of the disinfection could be enhanced, to some extent, by increasing the amount of TiO2 used. Cell concentrations were decreased by an order of 3 within 30 min of treatment in the presence of 1.0 g/ml TiO2. The disinfection power in the presence of TiO2 versus Al2O3 was also compared and the findings showed that TiO2 induced a higher cell killing. No significant effect of initial cell concentration on the disinfection was found in the range of 102-107 CFU/ml after a 30 min of treatment period. The mechanism of cell killing was investigated by examining the effects of OH radical scavengers such as ascorbic acid, histidine and glutathione. The disinfection power was reduced in samples that contained these radical scavengers, thus indicating the importance of OH radicals. 相似文献
8.
Nguyen-Dung Tien Sono Sasaki Hiroyasu Masunaga Nobutaka Shimizu Noriyuki Igarashi Shinichi Sakurai 《Polymer》2014
Direct determination of the discrete distribution for crystalline lamellar thickness has been performed for poly(d,l-lactic acid)/poly(oxyethylene) (PDLLA/PEG) blends by conducting small-angle X-ray scattering (SAXS) measurements using synchrotron radiation. The PDLLA used was an random (racemic) copolymer of bio-based poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) with the lactide monomer ratio of l:d = 50:50. It is known that PLA is miscible with PEG in the amorphous state. In the current paper, we report comprehensive results on structural analyses of PDLLA/PEG blends in the course of heating and cooling process using SAXS to elucidate the change in the thickness distribution of the lamellae. As a consequence, it was found that the distribution of the lamellar thickness moves toward the larger value (in other words, lamellar thickening) as temperature approaches the melting point. Typically, the thickness distribution was dispersed in the range of 10–20 nm at room temperature and it changed toward 40 nm in the vicinity of the melting temperature. To the best of our knowledge, this is the first report of direct determination of the discrete distribution for the crystalline lamellar thickness and their in-situ changes in the course of the lamellar thickening process. As a result, the lamellar thickening was found to occur at much lower temperature for the blend samples with 10% and 20% of PDLLA contents as compared to the PEG 100% sample. This phenomenon can be ascribed to the melting point depression owing to the miscibility between PEG and PDLLA. Thereby, thinner lamellae were melted and thicker ones appeared at much lower temperature for the blends than for the PEG 100% sample. As for the average repeating distance (long period) of the lamellar stacks, an abrupt increase similar to the critical divergence was observed (from 25 nm to 50 nm) in the heating process. Not only for the melting behavior but also in the course of recrystallization, change in the lamellar-thickness distribution was uncovered, which shows strong hysteresis depending on what temperature the sample was cooled down from. 相似文献
9.
Guanghui Cui Masamichi Fujikawa Shusaku Nagano Masami Sano Hiroshi Takase Tsukasa Miyazaki Shinichi Sakurai Katsuhiro Yamamoto 《Polymer》2014
Polystyrene-b-poly(methyl acrylate) (PS-b-PMA) block copolymer with PS volume fraction of 25.2 vol% was synthesized by atom transfer radical polymerization. Non-pretreated silicon wafers were used as the substrates to prepare perpendicular oriented PS cylinders in PMA matrix via solvent annealing which could induce the transformation of spheres to vertically oriented and hexagonally packed cylinders. The spherical microdomains were formed after the evaporation of solvents from the solutions of the block copolymer in selective solvents mixed from methanol, acetone and dichloromethane. The thickness of films could be as thick as 1000 nm, which were much thicker than usual cases and the cylinders came from the directional coalescence of the spheres, thus any pre-treatments of the substrates were not required for perpendicular orientation. The structures were characterized by small angle X-ray scattering (SAXS), transmission electron microscope (TEM), atom force microscopy (AFM) and grazing incidence small angle X-ray scattering (GISAXS). 相似文献
10.
Shi‐Kuan Sun Ya‐Ru Zhang Yuji Masubuchi Teruki Motohashi Shinichi Kikkawa 《Journal of the American Ceramic Society》2014,97(4):1023-1027
The maintaining of the chemical composition and electrical insulativity of SrTaO2N ceramics was investigated during sintering and annealing, using powders prepared by the nitridation of Sr2Ta2O7. Due to the low thermal stability of SrTaO2N, the partial loss of SrO and nitrogen induced the formation of a TaO0.9 impurity after heat‐treating at above 1100°C. The sintering additive SrCO3 and postannealing in NH3 were employed to compensate for the loss of SrO and nitrogen to obtain ceramics with the original chemical composition. The as‐sintered SrTaO2N ceramics with various relative density (RD) were annealed in NH3 to observe the recovery of color and electrical insulativity. It was found that the inner part of the well‐sintered samples with RD = 95.1% could not be recovered by annealing, and continued to exhibit semiconducting behavior and a black color. On the other hand, for the as‐sintered SrTaO2N ceramics with RD < 84%, both the nitrogen content and electrically insulating behavior were completely recovered after annealing. The postannealed SrTaO2N ceramics (RD = 83.3%) possessed a relatively large dielectric constant of 450 with a low dielectric loss of less than 0.1 at 100 Hz, almost independent of frequency and temperature. 相似文献