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Influence of deflection angles on flow behaviours in openchannel bends

Journal of Mountain Science 2018年第10期15卷 2292-2306页

作者： LI Bing-dong ZHANG Xin-hua TANG Han-song TSUBAKI ryota State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Department of Civil Engineering/City College City University of New York Department of Civil Engineering Nagoya University

The deflection angle of a river bend plays an important role on behaviours of the flow within it, and a clear understanding of the angle's influence is significant in both theoretical study and engineering application. This paper presents a systematic numerical investigation on effects of deflection angles(30°, 60°, 90°, 120°, 150°, and 180°) on flow phenomena and their evolution in open-channel bends using a Re-Normalization Group(RNG) κ-ε model and a volume of fluid(VOF) method. The numerical results indicate that the deflection angle is a key factor for flows in bends. It is shown that the maximum transverse slope of water surface occurs at the middle cross section of a bend, and it increases with the deflection angle. Besides a major vortex, or, the primary circulation cell near the channel bottom, a secondary vortex, or, an outer bank cell, may also appear above the former and near the outer bank when the deflection angle is sufficiently large, and it will gradually migrate towards the inner bank and evolve into an inner bank cell. The strength of the secondary circulations increases with the deflection angle. The simulation demonstrates that there is alow-stress zone on the bed near the outer bank and a high-stress zone on the bed near the inner bank, and both of them increase in size with the deflection angle. The maximum of shear stress on the inner bank increases nonlinearly with the angle, and its maximums on the outer bank and on the bed take place when the deflection angle becomes 120°.

关键词： Open channel Deflection angle Transverse slope of water surface Secondary flow Shear stress

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Stochastic model predictive braking control for heavy-duty commercial vehicles during uncertain brake pressure and road profile conditions

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Control Theory and Technology 2022年第2期20卷 248-262页

作者： ryota Nakahara Kazuma Sekiguchi Kenichiro Nonaka Masahiro Takasugi Hiroki Hasebe Kenichi Matsubara Graduate School of Integrative Science and Engineering Tokyo City UniversityTamazutsumiSetagaya-kuTokyo 1588557Japan Nabtesco Automotive Co. Ltd.HirakawachoChiyoda-kuTokyo 1020093Japan

When heavy-duty commercial vehicles(HDCVs)must engage in emergency braking,uncertain conditions such as the brake pressure and road profile variations will inevitably affect braking *** minimize these uncertainties,we propose a combined longitudinal and lateral controller method based on stochastic model predictive control(SMPC)that is achieved via Chebyshev–Cantelli *** our method,SMPC calculates braking control inputs based on a finite time prediction that is achieved by solving stochastic programming elements,including chance *** accomplish this,SMPC explicitly describes the probabilistic uncertainties to be used when designing a robust control *** main contribution of this paper is the proposal of a braking control formulation that is robust against probabilistic friction circle uncertainty *** specifically,the use of Chebyshev–Cantelli inequality suppresses road profile influences,which have characteristics that are different from the Gaussian distribution,thereby improving both braking robustness and control performance against statistical ***,since the Kalman filtering(KF)algorithm is used to obtain the expectation and covariance used for calculating deterministic transformed chance constraints,the SMPC is reformulated as a KF embedded deterministic ***,the effectiveness of our proposed method is verified via a MATLAB/Simulink and TruckSim co-simulation.

关键词： Heavy-duty commercial vehicle Brake system Stochastic model predictive control Road profile

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An antioxidant resveratrol significantly enhanced replication of hepatitis C virus

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World Journal of Gastroenterology 2010年第2期16卷 184-192页

作者： Mitsuyasu Nakamura Masanori Ikeda ryota Hokari Nobuyuki Kato Toshifumi Hibi Soichiro Miura Department of Internal Medicine 2 National Defense Medical Collage3-2 NamikiTokorozawaSaitama 3598513Japan Department of Internal Medicine School of MedicineKeio University35 ShinanomachiShinjuku-kuTokyo 1608582 Japan Department of Internal Medicine School of MedicineKeio University35 ShinanomachiShinjuku-kuTokyo 1608582 Japan Masanori Ikeda Department of Molecular Biology Okayama University Graduate School of Medicine and Dentistry2-5-1 Shikada-choOkayama 7008558Japan Department of Internal Medicine School of MedicineKeio University35 ShinanomachiShinjuku-kuTokyo 1608582 Japan Masanori Ikeda

AIM:To elucidate the effect of antioxidants,resveratrol (RVT)and astaxanthin(AXN),on hepatitis C virus(HCV) replication. METHODS:We investigated the effect of recent popular antioxidant supplements on replication of the HCV replicon system *** is a strong antioxidant and a kind of polyphenol that inhibits replication of various *** is also a strong *** replication of HCV RNA was assessed by the luciferase reporter *** additive effect of antioxidants on antiviral effects of interferon(IFN)and ribavirin(RBV) was ***:This is the first report to investigate the effect of RVT and AXN on HCV *** contrast to other reported viruses,RVT significantly enhanced HCV RNA *** E also enhanced HCV RNA replication as reported previously,although AXN didnot affect *** and RBV significantly reduced HCV RNA replication,but these effects were dose-dependently hampered and attenuated by the addition of *** didnot affect antiviral effects of IFN or RBV. CONCLUSION:These results suggested that RVT is not suitable as an antioxidant therapy for chronic hepatitis C.

关键词： Replicon system Luciferase assay Ribavirin Interferon Polyphenol Astaxanthin

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Experimental Evaluation of the Post-ultimate Strength Behavior of a Ship＇s Hull Girder in Waves

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Journal of Marine Science and Application 2012年第1期11卷 34-43页

作者： Kazuhiro Iijima ryota Wada Masahiko Fujikubo Department of Naval Architecture and Ocean Engineering Osaka UniversityOsaka 565-0871Japan

Experimental investigations into the collapse behavior of a box-shape hull girder subjected to extreme wave-induced loads are *** experiment was performed using a scaled model in a *** the middle of the scaled model,sacrificial specimens with circular pillar and trough shapes which respectively show different bending moment-displacement characteristics were mounted to compare the dynamic collapse characteristics of the hull girder in *** specimens were designed by using finite element(FE)-*** to the tank tests,static four-point-bending tests were conducted to detect the load-carrying capacity of the hull *** was shown that the load-carrying capacity of a ship including reduction of the capacity after the ultimate strength can be reproduced experimentally by employing the trough type *** tests using these specimens were performed under a focused wave in which the hull girder collapses under once and repetitive focused *** was shown from the multiple collapse tests that the increase rate of collapse becomes higher once the load-carrying capacity enters the reduction path while the increase rate is lower before reaching the ultimate strength.

关键词： post-ultimate strength collapse behavior experimental evaluation load-carrying capacity hull girder

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Groundwater monitoring of an open-pit limestone quarry:Water-rock interaction and mixing estimation within the rock layers by geochemical and statistical analyses

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International Journal of Mining Science and Technology 2018年第6期28卷 849-857页

作者： Khy Eam Eang Toshifumi Igarashi Megumi Kondo Tsurugi Nakatani Carlito Baltazar Tabelin ryota Fujinaga Laboratory of Groundwater and Mass Transport Division of Sustainable Resources EngineeringGraduate School of EngineeringHokkaido UniversitySapporo 060-8628Japan Laboratory of Groundwater and Mass Transport Division of Sustainable Resources EngineeringFaculty of EngineeringHokkaido UniversitySapporo 060-8628Japan Mitsubishi Materials Corporation Tokyo 1008117Japan Ryoko Lime Industry Co. Ltd.Chichibu-gunSaitama 3680072Japan Laboratory of Mineral Processing and Resources Recycling Division of Sustainable Resources EngineeringFaculty of EngineeringHokkaido UniversitySapporo 0608628Japan

Water-rock interaction and groundwater mixing are important phenomena in understanding hydrogeological systems and the stability of rock slopes especially those consisting largely of moderately watersoluble minerals like calcite. In this study, the hydrogeological and geochemical evolutions of groundwater in a limestone quarry composed of three strata: limestone layer(covering), interbedded layer under the covering layer, and slaty greenstone layer(basement) were investigated. Water-rock interaction in the open-pit limestone quarry was evaluated using PHREEQC, while hierarchical cluster analysis(HCA)and principal component analysis(PCA) were used to classify and identify water sources responsible for possible groundwater mixing within rock layers. In addition, Geochemist's Workbench was applied to estimate the mixing fractions to clarify sensitive zones that may affect rock slope stability. The results showed that the changes in Ca2+and HCO3àconcentrations of several groundwater samples along the interbedded layer could be attributed to mixing groundwater from the limestone layer and that from slaty greenstone layer. Based on the HCA and PCA results, groundwaters were classified into several types depending on their origin:(1) groundwater from the limestone layer(LO),(2) mixed groundwater flowing along the interbedded layer(e.g., groundwater samples L-7, L-11, S-3 and S-4), and(3) groundwater originating from the slaty greenstone layer(SO). The mixing fractions of 41% LO: 59% SO, 64% LO: 36% SO, 43%LO: 57% SOand 25% LO: 75% SOon the normal days corresponded to groundwaters L-7, L-11, S-3 and S-4,respectively, while the mixing fractions of groundwaters L-7 and L-11(61% LO: 39% SOand 93% LO: 7% SO,respectively) on rainy days became the majority of groundwater originating from the limestone *** indicate that groundwater along the interbedded layer significantly affected the stability of rock slopes by enlarging multi-breaking zones in the layer through calcite

关键词： Water-rock interaction Groundwater mixing Interbedded layer Geochemist’s workbench Rock slope stability

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Hepatic reconstruction from fetal porcine liver cells using a radial flow bioreactor

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World Journal of Gastroenterology 2008年第17期14卷 2740-2747页

作者： Yuji Ishii ryota Saito Hideki Marushima Ryusuke Ito Taro Sakamoto Katsuhiko Yanaga Department of Surgery the Jikei University School of Medicine

AIM： To examine the efficacy of the radial flow bioreactor （RFB） as an extracorporeal bioartificial liver （BAL） and the reconstruction of liver organoids using embryonic pig liver cells. METHODS： We reconstructed the liver organoids using embryonic porcine liver cells in the RFB. We also determined the gestational time window for the optimum growth of embryonic porcine liver cells. Five weeks of gestation was designated as embryonic day （E） 35 and 8 wk of gestation was designated as E56. These cells were cultured for one week before morphological and functional examinations. Moreover, the efficacy of pulsed adminisbation of a high concentration hepatocyte growth factor （HGF） was examined. RESULTS： Both cell growth and function were excellent after harvesting on E35. The pulsed administration of a high concentration of HGF promoted the differentiation and maturation of these fetal hepatic cells. Microscopic examination of organoids in the RFB revealed palisading and showed that bile duct-like structures were well developed, indicating that the organoids were mini livers. Transmission electron microscopy revealed microvilli on the luminal surfaces of bile duct-like structures and junctional complexes, which form the basis of the cytoskeleton of epithelial tissues. Furthermore, strong expression of connexin （Cx） 32, which is the main protein of hepatocyte gap junctions, was observed. With respect to liver function, ammonia detoxification and urea synthesis were shown to be performed effectively. CONCLUSION： Our system can potentially be applied in the fields of BAL and transplantation medicine.

关键词： Liver organoid Radial flow bioreactor Bioartificial liver Fetal porcine liver Hepatocyte growthfactor

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First principles calculation of stable structure and adhesive strength of plated Ni/Fe(100) or Cu/Fe(100) interfaces

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中国有色金属学会会刊：英文版 2009年第4期19卷 988-991页

作者： ryota NAKANISHI Koji SUEOKA Seiji SHIBA M akoto HINO Koji MURAKAMI Ken MURAOKA Department of System Engineering Okayama Prefectural University Metallic Materials Group Department of Mechanical EngineeringIndustrial Technology Center of Okayam a Prefecture

A study the with first principles calculation of the interfaces of the Ni layer or Cu layer on the Fe(100) surface formed with metal plating was *** or Cu atoms were shown to adopt the corresponding position to the bcc structure of the Fe(100) *** calculations showed that the interfaces of Ni(5 atomic layers)/Fe(100)(5 layers) or Cu(5 atomic layers)/Fe(100)(5 layers) had square *** orientation relationship of Ni/Fe(100) interface corresponds to fcc-Ni(100)//bcc-Fe(100),Ni[011]//Fe[010],and Ni[011]//Fe[001].Similar results were obtained for Cu/Fe(100) *** structure was supported by TEM analysis of plated Ni layer on Fe(100) *** adhesion strength of the Ni/Fe(100) interface evaluated by first principles calculation was higher than that of the Cu/Fe(100) *** experimental results of Hull cell iron plated with Ni or Cu supported the results of the *** results indicate that the first principles calculation,which deals with the ideal interface at the atomic scale,has the potential to evaluate the adhesion strength of metallic material interfaces.

关键词：第一原理计算接口处理稳定结构粘接强度铜原子镀镍胶粘剂界面结合强度

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Possibility of avoiding legumes-deriving boost of N 2 O emissions in tropical monoculture tree plantations

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Journal of Forestry Research 2023年第2期34卷 565-573页

作者： Taiki Mori Chongrak Wachrinrat Duriya Staporn ryota Aoyagi Ponthep Meunpong Warawich Suebsai Khitja Boonsri Kanehiro Kitayama Forest Ecology Laboratory Graduate School of AgricultureKyoto UniversityKitashirakawa Oiwake-cho Sakyo-kuKyoto 606-8502Japan Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical GardenChinese Academy of SciencesGuangzhou 510650GuangdongPeople’s Republic of China Forestry and Forest Products Research Institute FFPRI 1 MatsunosatoTsukubaIbaraki 305-8687Japan Faculty of Forestry Kasetsart UniversityChatuchakBangkok 10900Thailand Smithsonian Tropical Research Institute Bocas TownIsla AncónRepublic of Panama

Recent reports warned that planting leguminous trees under monocultures elevates nitrous oxide(N2O)emissions through N-rich litter *** hypothesized that planting trees on sandy soil can avoid the legume-derived boost of N2O emissions through limiting water availability for N2O *** of planting legumes on methane(CH4)uptakes were also examined.N2O emissions and CH4uptakes were compared among five tropical tree plantation stands including three leguminous stands(Acacia auriculiformis,Acacia mangium,and Xylia xylocarpa)and two non-leguminous stands(Eucalyptus camaldulensis,and Hope a odorata).Due to lower water contents of the soil,the N2O fluxes in our study site were at the lower end of the tropical rain *** we hypothesized,no clear differences in N2O emissions were obs erved between leguminous and non-leguminous ***4uptake rates in the present study were lower than those of other tropical ***4uptakes in leguminous stands did not differ from those in non-leguminous ***,we demonstrated that planting leguminous trees on sandy soils has a potential to enable us to manage leguminous monoculture tree plantations without boosting N2O emissions or reducing CH4uptakes.

关键词： Nitrous oxide Methane Fast-growing trees Tropical forest Soil texture

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Comparison between combination therapy of percutaneous ethanol injection and radiofrequency ablation and radiofrequency ablation alone for patients with hepatocellular carcinoma

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World Journal of Gastroenterology 2005年第10期11卷 1426-1432页

作者： Kazutaka Kurokohchi Seishiro Watanabe Tsutomu Masaki Naoki hosomi Yoshiaki Miyauchi Takashi Himoto Yasuhiko Kimura Seiji Nakai Akihiro Deguchi Hirohito Yoneyama Shuhei Yoshida Shigeki Kuriyama Third Department of Internal Medicine

AIM: In the present study, the characteristics of PEI-RFA treatment were further elucidated by analyzing the relationship between the volume of coagulated necrosis and the energy requirement for ablation or the amount of ethanol injected into ***: The volume of coagulated necrosis, total energy requirement and energy requirement for coagulation of per unit volume were examined in the groups of PEI-RFA and RFA alone using the Cool-tip RF ***: The results showed that the volume of coagulated necrosis induced was significantly larger in PEI-RFA group than in routine RFA group, when the total energy administered was comparable in both *** PEI-RFA, enlargement of coagulated necrosis was admitted in 3 dimensions and the amount of energy requirement per unit volume of coagulated necrosis was negatively correlated with the amount of ethanol injected into ***: These results suggest that, compared to RFA alone, PEI-RFA enables to induce comparable coagulated necrosis with smaller energy requirement, and that PEI-RFA is likely to be less invasive than RFA alone irrespective of inducing enhanced coagulated ***, simple prior injection of ethanol may make RFA treatment more effective and less invasive for the treatment of patients with HCC.

关键词： Combination therapy Percutaneous ethanol injection Radiofrequency ablation Energy requirement

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Influence of morphology of hollow silica-alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane

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Journal of Advanced Ceramics 2017年第4期6卷 368-375页

作者： Naoki TOYAMA ryota OGAWA Haruki INOUE Shinobu OHKI Masataka TANSHO Tadashi SHIMIZU Tetsuo UMEGAKI Yoshiyuki KOJIMA Department of Materials&Applied Chemistry College of Science&EngineeringNihon University1-8-14Kanda-SurugadaiChiyoda-KuTokyo 101-8308Japan National Institute for Materials Science 3-13SakuraTsukubaIbaraki 305-0003Japan

Hollow silica-alumina composite spheres were prepared by a polystyrene(PS)template method using various amounts of PS *** hollow spheres prepared using 40 g were found to be with a diameter of about 300 nm in scanning electron microscopy,and transmission electron microscopy demonstrated their hollow sphere *** the nitrogen adsorption isotherm results,the homogeneous hollow spheres prepared using 40 g of the PS suspension were found to be an ordered pore *** activities of the hollow spheres prepared using various amounts of the PS suspension for hydrolytic dehydrogenation of ammonia borane were *** results showed that 10,7,and 6 mL of hydrogen were evolved from the aqueous ammonia borane solution in about 40 min in the presence of the hollow spheres prepared using 40,80,and 120 g of PS suspension,*** homogeneous hollow spheres with an ordered pore structure showed the highest activity among all the hollow *** amount of acid sites and the coordination number of aluminum active species were characterized using neutralization titration and solid-state ^(27)Al magic angle spinning nuclear magnetic resonance *** homogeneous hollow spheres with an ordered pore structure had high amount of acid sites and 4-coordinated aluminum *** relative proportion of 4-coordinated aluminum species was related to the dispersion of aluminum *** results indicate that the homogeneous hollow spheres with an ordered pore structure showed the high activity because of high amount of acid sites induced by the highly dispersed aluminum species.

关键词： ammonia borane morphology hollow silica-alumina composite spheres dispersion acid sites

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