44 research outputs found

    An Application of Semi-empirical Physical Model of Tsunami-Bore Pressure on Buildings

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    Characteristic patterns of tsunami wave pressure on buildings is divided into three types, depending on its vertical profiles and time, which is observed after the tsunami impacted the buildings. The first one is the impulsive pressure, which is observed just after the tsunami impacted the buildings. The second one is the bore pressure, which is observed after the impulsive pressures. The third one is the quasi-steady pressure, which is observed after the bores go away from the buildings. In this study, based on characteristics of bore pressure observed in a hydraulic experiment, a semi-empirical physical model of bore pressure is developed by applying a turbulent bore theory. Also, we present an application method of the semi-empirical physical model to evaluations of bore pressure with usage of numerical results of inundation simulations of two-dimensional nonlinear shallow water equation models. Furthermore, we apply the semi-empirical physical model to evaluations of pressure acting on buildings in an inundation area by carrying out numerical simulations of tsunami inundation

    Validation of tsunami numerical simulation models for an idealized coastal industrial site

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    Numerous tsunami numerical models have been proposed, but their prediction accuracies have not been directly compared. For quantifying the modeling uncertainties, the authors statistically analyzed the prediction results submitted by participants in the tsunami blind contest held at the 17th World Conference on Earthquake Engineering. The reproducibility of offshore water level generated due to the tsunami with soliton fission significantly decreased when the nonlinear shallow water equation models (NSWE) was used compared to three-dimensional (3D) models. The inundation depth was reproduced well in 3D models. However, the reproducibility of wave forces acting on the structure and velocities over land was lower in 3D models than that in NSWE models. For cases where the impulsive tsunami wave pressure generated could not be calculated based on the hydrostatic assumption, the prediction accuracy of the NSWE models was higher than that of the 3D models. The prediction accuracies of both models were not improved at small grid-cell sizes. The NSWE model cannot simulate the short-wave component and vertical pressure distribution. Therefore, further developments in 3D models and smoothed particle hydrodynamics methods (SPH) are needed. The presented results contribute to the future development of tsunami numerical simulation tools.Peer Reviewed"Article signat per 34 autors/es: Masashi Watanabe,Taro Arikawa,Naoto Kihara,Chiaki Tsurudome,Koichi Hosaka,Tatsuto Kimura,Takayuki Hashimoto,Fumitaka Ishihara,Takemi Shikata,Daniel Shigueo Morikawa,Taiga Makino,Mitsuteru AsaiORCID Icon,Yu Chida,Yoichi Ohnishi,Simone Marras,Abhishek Mukherjee,Juan Carlos Cajas,Guillaume Houzeaux,B D Paolo, Javier L. Lara,Gabriel Barajas, Íñigo J. Losada,Masanobu Hasebe,Yoshinori Shigihara Tatsuya Asai,Tsuyoshi Ikeya,Shusaku Inoue,Hideo Matsutomi,Yoshiaki Nakano,Yasuo Okuda,Shunya Okuno,Takayuki Ooie,Gaku Shoji &Tomokazu Tateno "Postprint (published version

    Review of juxtaglomerular cell tumor with focus on pathobiological aspect

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    Juxtaglomerular cell tumor (JGCT) generally affects adolescents and young adults. The patients experience symptoms related to hypertension and hypokalemia due to renin-secretion by the tumor. Grossly, the tumor is well circumscribed with fibrous capsule and the cut surface shows yellow or gray-tan color with frequent hemorrhage. Histologically, the tumor is composed of monotonous polygonal cells with entrapped normal tubules. Immunohistochemically, tumor cells exhibit a positive reactivity for renin, vimentin and CD34. Ultrastructurally, neoplastic cells contain rhomboid-shaped renin protogranules. Genetically, losses of chromosomes 9 and 11 were frequently observed. Clinically, the majority of tumors showed a benign course, but rare tumors with vascular invasion or metastasis were reported. JGCT is a curable cause of hypertensive disease if it is discovered early and surgically removed, but may cause a fatal outcome usually by a cerebrovascular attack or may cause fetal demise in pregnancy. Additionally, pathologists and urologists need to recognize that this neoplasm in most cases pursues a benign course, but aggressive forms may develop in some cases

    Large-scale animal model study uncovers altered brain pH and lactate levels as a transdiagnostic endophenotype of neuropsychiatric disorders involving cognitive impairment

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    DIRECT NUMERICAL SIMULATION ON THE MOMENTUM AND SCALAR TRANSFER OVER WIND WAVES

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    Elastic-constant measurement in oxide and semiconductor thin films by Brillouin oscillations excited by picosecond ultrasound

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    In this study, an elastic-stiffness evaluation in transparent or translucent thin films using Brillouin oscillations detected by picosecond ultrasound is conducted. An ultrahigh-frequency (≥50 GHz) strain pulse is generated using femtosecond light pulse in specimens and propagates in the film-thickness direction. The time-delayed probe light pulse enters the specimen, which is diffracted by the strain pulse, causing oscillations in the reflectivity change of the probe light pulse. The oscillation frequency gives the elastic modulus with ellipsometry for refractive index. The theoretical calculation predicts the accuracy of stiffness measurement. The methodology is applied to the study of amorphous silica, amorphous tantalum oxide, diamond thin films, and silicon wafers.Hirotsugu Ogi, Tomohiro Shagawa, Nobutomo Nakamura, Masahiko Hirao, Hidefumi Odaka and Naoto Kihara. Elastic-constant measurement in oxide and semiconductor thin films by Brillouin oscillations excited by picosecond ultrasound. Japanese Journal of Applied Physics, 2009, 48(7S), 07GA01. https://doi.org/10.1143/JJAP.48.07GA01
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