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41.
Hiroyuki Hamada Hiroyuki Kato Naoto Ito Yoshihiko Takase Hironobu Nanbu Shoko Mishima Hiromu Sakaki Kiyotaka Sato 《European Journal of Lipid Science and Technology》2010,112(12):1323-1330
Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures. 相似文献
42.
Koji Yamada Kiyotaka Tomari Umaru Semo Ishiaku Hiroyuki Hamada 《Polymer Engineering and Science》2005,45(8):1059-1066
Fracture toughness of adjacent flow weld lines, defined as weld lines that occur when two flow fronts meet and continue to flow together in the same direction (meld line or hot weld line), was evaluated by the single‐edge notched‐bend (SENB) method using three differently‐shaped obstructive pins. Although the fracture toughness varied depending upon the shapes of the pin, the values could be standardized as the distance from the meeting point of the two flow fronts flowing around the pin. The fracture toughness decreased drastically from the meeting point along the weld line and then slightly increased. These characteristic features could be explained by flow‐induced molecular orientation at the weld line interface. The molecules around the meeting point that were initially oriented parallel to the weld line due to fountain flow were able to relax, and then entanglement across the weld line interface developed because the flow stopped in the middle of the filling process, resulting in high fracture toughness. In contrast, the material at the downstream side of the weld line continued flowing during the filling process, being stretched along the flow direction. So, the molecular orientation at this area could not relax. In addition, the V‐notch shape, i.e., the depth and length at the surface of the weld line, which also varied depending on the shape of the obstacles, was considered to be identical when the meeting point was allowed to be a datum point. Thus, the meeting point was found to be a significant factor when the properties of weld lines are investigated. POLYM. ENG. SCI., 45:1059–1066, 2005. © 2005 Society of Plastics Engineers 相似文献
43.
Laura Bayés-García;Kiyotaka Sato;Lu Zhang;Shinichi Yoshikawa;Fumitoshi Kaneko;Yoshinori Yamamoto;Shimpei Watanabe;Ken Taguchi; 《Journal of the American Oil Chemists' Society》2024,101(1):79-93
The triacylglycerols (TAGs) containing saturated (Sat)-unsaturated (U) fatty acid moieties (Sat-U mixed acid TAGs) are widely present in most natural fats and employed in many industrial applications. The mixing behavior of different Sat-U mixed acid TAGs acts important roles in the physicochemical properties TAG-based materials. Among the three main mixing states of miscible, eutectic and molecular compound (MC) forming mixtures, fundamental research has been conducted on the MC crystals formed by different Sat-U mixed acid TAGs to understand the structures, phase behavior and crystallization properties. This article reviews studies to date on the complex thermodynamic, kinetic and structural factors that affect the formation of MC crystals in binary and ternary mixtures of Sat-U mixed acid TAGs (SatUSat, SatSatU, USatU and UUSat) through specific molecular interactions among the component TAGs. Furthermore, the application of the MC-forming mixtures containing cacao butter to new types of cocoa butter alternative is reviewed. 相似文献
44.
A Onitsuka H Hirose Y Ozeki A Hino S Senga T Iida 《Canadian Metallurgical Quarterly》1995,80(2):128-130
In a consecutive series of 146 patients with hepatocellular carcinoma (HCC), 10 patients (6.8%) were found to have one or two extrahepatic malignancies (EHM). Of these, eight had double cancers and two, triple cancers. The associated malignancies included eight cases of gastric cancer and four cases of colon cancer. Among the 12 lesions, eight were in the early stage. All the 10 patients were hepatitis B surface antigen negative. The incidence of coexisting liver cirrhosis and the retention rate of indocyanin green in 15 minutes among HCCs with EHM were significantly lower than those among HCC alone. These results suggest that the etiology of HCC with EHM is different from the etiology of HCC alone in Japan. 相似文献
45.
The rates of melt crystallization and phase transformation of three polymorphs of tripalmitin were examined by optical microscopy,
X-ray diffractometry and DSC with and without surfactant additives (sorbitan mono- and tristearates). The following results
were obtained: (a) Crystallization rate increased in order ofα, β′ andβ; (b) transformation rate was slower than crystallization rate for each polymorph at the same temperature examined; (c) when
the most stableβ form was recrystallized from the melt just after the melting ofα, its recrystallization rate was much higher than that by simple melt-cooling; (d) surfactant additives retarded both the
crystallization and transformation of all the polymorphs, yetβ′ was influenced the most. A mechanistic interpretation based on the molecular structures both of the melt and of each polymorph
is presented. 相似文献
46.
Kiyotaka Yamamura Shigeru Tanaka 《International Journal of Circuit Theory and Applications》2001,29(4):403-411
In this letter, an effective technique is proposed for improving the computational efficiency of the contraction‐type LP test algorithm, which is an algorithm for finding all solutions of piecewise‐linear resistive circuits. Using the proposed technique, all solutions of a large‐scale problem, where the number of variables is 100 and the number of linear regions is 10100, could be found in less than 10 min using a 360 MHz computer. Copyright 2001 John Wiley & Sons, Ltd. 相似文献
47.
Shintaro Sugahara Yuto Ueda Kumiko Fukuhara Yuki Kamamuta Yasushi Matsuda Tatsuro Murata Yasuhiro Kuroda Kiyotaka Kabata Masateru Ono Keiji Igoshi Shin Yasuda 《Journal of food science》2015,80(11):C2420-C2429
Yacon (Smallanthus sonchifolius), a native Andean plant, has been cultivated as a crop and locally used as a traditional folk medicine for the people suffering from diabetes and digestive/renal disorders. However, the medicinal properties of this plant and its processed foods have not been completely established. This study investigates the potent antioxidative effects of herbal tea leaves from yacon in different free radical models and a ferric reducing model. A hot‐water extract exhibited the highest yield of total polyphenol and scavenging effect on 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) radical among four extracts prepared with hot water, methanol, ethanol, and ethylacetate. In addition, a higher reducing power of the hot‐water extract was similarly demonstrated among these extracts. Varying concentrations of the hot‐water extract resulted in different scavenging activities in four synthetic free radical models: DPPH radical (EC50 28.1 μg/mL), 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) cation radical (EC50 23.7 μg/mL), galvinoxyl radical (EC50 3.06 μg/mL), and chlorpromazine cation radical (EC50 475 μg/mL). The yacon tea‐leaf extract further demonstrated superoxide anion (O2?) radical scavenging effects in the phenazine methosulfate‐NADH‐nitroblue tetrazolium (EC50 64.5 μg/mL) and xanthine oxidase assay systems (EC50 20.7 μg/mL). Subsequently, incubating human neutrophilic cells in the presence of the tea‐leaf extract could suppress the cellular O2? radical generation (IC50 65.7 μg/mL) in a phorbol 12‐myristate 13‐acetate‐activated cell model. These results support yacon tea leaves may be a good source of natural antioxidants for preventing O2? radical‐mediated disorders. 相似文献
48.
Structures of Rh/1 AL (atomic layer) GeO2/SiO2 were studied during reduction and oxidation processes by means of in situ XAFS (X-ray absorption fine structure). It was found that RhGe bimetallic particles with Rh--Rh and Rh--Ge distances at 0.266 and 0.242 nm were formed after reduction at 723 K, respectively. Subsequent oxidation at 673 K regenerated 1 AL GeO2 structure on the SiO2 surface. This reversible structure transformation is discussed in relation to reactivity and volatility of Ge oxide species. 相似文献
49.
Iwao Hachiya Tetsuo Koyano Kiyotaka Sato 《Journal of the American Oil Chemists' Society》1989,66(12):1757-1762
Effects of seeding of fat crystals on the crystallization kinetics of cocoa butter and dark chocolate were examined with a
rotational viscometer. The seed crystals employed were cocoa butter, 1,3-distearoyl-2-oleoylglycerol (SOS), 1,3-dibehenoyl-2-oleoylglycerol
(BOB) and 1,2,3-tristearoylglycerol (SSS). The seed powders were prepared by pulverization below —50°C, the dimensions being
in a range from 20–70 μm. Particular attention was paid to the influence of polymorphism of the seed crystal. We found that
all of the above seed materials accelerated the crystallization, the degree of acceleration being in a following order; SOS
(β
1) > cocoa butter (Form V) > SOS (a mixture ofβ’ andβ
2) > BOB (β
2) > BOB (pseudo-β’) > SSS (β). Precise measurements of the crystallization kinetics showed that the most influential factors in the seeding
effects are the physical properties of the seed materials—above all, thermodynamic stability, and similarity in the crystal
structure to cocoa butter are the most determinative. 相似文献
50.
Keisuke Ichida Kiyotaka Izumi Keigo Watanabe Nobuhiro Uchida 《Artificial Life and Robotics》2008,12(1-2):258-263
In general, manipulators used for industry and in academic laboratories have actuators to drive each joint. On the other hand,
underactuated manipulators handled by our research have some passive or free joints without actuators and brakes. We recently
developed a switching method of fuzzy energy regions to control such manipulators. In such a method, it is necessary to design
parameters related to energy regions and the gains of some partly stable controllers based on the computed torque method.
Here, the switching method is applied for a three-link underactuated manipulator. We optimize such design parameters related
to fuzzy energy regions by a genetic algorithm. The effectiveness of the present method is illustrated with some simulations.
This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January
25–27, 2007 相似文献