Three-dimensional antidunes coexisting with alternate bars     

Takuya Inoue  Yasunori Watanabe  Toshiki Iwasaki  Junichi Otsuka 《地球表面变化过程与地形》2020,45(12):2897-2911

Antidunes are fluvial bedforms that form in rivers with supercritical flows. The water surface over antidunes is strongly in phase with the bed surface, and the water surface is amplified to produce large surface waves. Many experimental studies have addressed antidunes; however, the shapes of three-dimensional antidunes in a wide channel with alternate bars have not yet been appropriately understood. In this study, we experimentally investigated the streamwise and transverse length scales of antidunes under conditions with a large width–depth ratio. Our experimental results provide evidence for the coevolution of antidunes and free alternate bars, and show for the first time that the development of free bars greatly alters the three-dimensional shape of water surface waves over antidunes. In the absence of free bars in a wide channel, multiple longitudinal wave trains form, and the number of wave trains counted in the transverse direction increases with increases in the width–depth ratio. However, the presence of free bars affects the local flow characteristics, resulting in a decrease of the number of wave trains in the transverse direction. Therefore, we propose a simple model for predicting the reduction in the number of wave trains by combining two previous theories for antidunes and free bars. Results obtained by the model were found to largely agree with experimental observations. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd  相似文献   

Real-time hybrid experimental system with actuator delay compensation and its application to a piping system with energy absorber     

T. Horiuchi  M. Inoue  T. Konno  Y. Namita 《地震工程与结构动力学》1999,28(10):1121-1141

A real-time hybrid experimental method, in which output from an actuator-excited vibration experiment and response calculation are combined on-line and conducted simultaneously in real time, is being developed as a new seismic experimental method for structural systems. In real-time hybrid experiments, however, there is an inevitable actuator-response delay, which has an effect equivalent to negative damping. To solve this problem, a real-time hybrid experimental system (including an actuator-delay compensation method) was developed. And seismic experiments were conducted in order to demonstrate the advantages of this system. Experimental results obtained using the developed hybrid experimental system were compared with exact results obtained using shaking-table experiments, and it was found that the two experimental methods gave almost identical results. It can therefore be concluded that the structural response can be obtained precisely by using the developed hybrid experimental system. Comparison of these experiments showed the advantages of the hybrid experiments; that is, they are simple and economical. This is because the hybrid experiment requires only a small structure as the excitation model, while a shaking-table experiment must consider the whole structural system. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

The radio to infrared emission of very high redshift gamma-ray bursts: probing early star formation through molecular and atomic absorption lines     

Susumu Inoue  Kazuyuki Omukai  Benedetta Ciardi 《Monthly notices of the Royal Astronomical Society》2007,380(4):1715-1728

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Simple coprecipitation method combined with low-background γ-spectrometry: Determination of 7Be, 137Cs, 210Pb, and radium and thorium isotopes in small-volume coastal water samples     

Yusuke Nakano  Mutsuo Inoue  Kazuhisa Komura 《Journal of Oceanography》2008,64(5):713-717

Application of a coprecipitation method combined with low-background γ-spectrometry allowed the isolation of ⁷Be, ¹³⁷Cs, ²¹⁰Pb, and radium and thorium isotopes together with BaSO₄, Fe(OH)₃, or AMP/Cs in 18 L of coastal water. This simple method showed high chemical yields of 77–91% (mean, 85%) for ²¹⁰Pb and radium isotopes, 87–92% (mean, 91%) for 7Be and thorium isotopes, and 98% for ¹³⁷Cs. The activity of the nuclides showed good reproducibility with standard deviations of 1–8%, while the deviation of activity in particle-reactive ²¹⁰Pb (32%) and ⁷Be (21%) in filtered water samples was exceptionally large.  相似文献   

A new high-stress undrained ring-shear apparatus and its application to the 1792 Unzen–Mayuyama megaslide in Japan     

Kyoji Sassa  Khang Dang  Bin He  Kaoru Takara  Kimio Inoue  Osamu Nagai 《Landslides》2014,11(5):827-842

Sassa and others in the Disaster Prevention Research Institute (DPRI), Kyoto University, developed a series of undrained ring-shear apparatus to physically simulate landslide initiation and motion, from DPRI-3 (Sassa 1992) to DPRI-7 (Sassa et al., Landslides 1(1):7–19, 2004). The maximum undrained capacities in the DPRI series ranged from 300 to 650 kPa. Sassa and others in the International Consortium on Landslides (ICL) have developed a new series of undrained ring-shear apparatus (ICL-1and ICL-2) for two projects of the International Programme on Landslides (IPL-161 and IPL-175). Both projects are supported by the Science and Technology Research Partnership for Sustainable Development Program (SATREPS) of Japan. ICL-1 was developed to create a compact and transportable apparatus for practical use in Croatia; one set was donated to Croatia in 2012. ICL-2 was developed in 2012–2013 to simulate the initiation and motion of megaslides of more than 100 m in thickness. The successful undrained capacity of ICL-2 is 3 MPa. This apparatus was applied to simulate possible conditions for the initiation and motion of the 1792 Unzen–Mayuyama megaslide (volume, 3.4?×?10⁸ m³; maximum depth, 400 m) triggered by an earthquake. The megaslide and resulting tsunami killed about 15,000 people. The Unzen Restoration Office of the Ministry of Land, Infrastructure and Transport (MLIT) of Japan systematically collected various papers and reports and published two summary leaflets: one in English in 2002 and an extended version in Japanese in 2003. Samples were taken from the source area (for initiation) and the moving area (for motion). The hazard area was estimated by the integrated landslide simulation model LS-RAPID, using parameters obtained with the ICL-2 undrained ring-shear apparatus. The estimated hazard area agrees reasonably with the landslide moving area reported in the Ministry leaflets.  相似文献   

Relationship between surface morphology and chemical composition of spheroidal carbonaceous particles within sediment core samples recovered from Osaka Bay,Japan     

Akiko Murakami-Kitase  Takamoto Okudaira  Jun Inoue 《Environmental Earth Sciences》2010,59(8):1723-1729

Spheroidal carbonaceous particles (SCPs) are produced by the high-temperature combustion of fossil fuels and are emitted to the atmosphere. Previous studies are divided regarding whether SCPs derived from the combustion of various fossil fuels can be identified based on their surface morphologies and chemical compositions. In this study, we examined the surface morphology and chemical composition of SCPs in sediment core samples collected from Osaka Bay, Japan, with the aim of evaluating the usefulness of SCPs morphology in identifying their origin. Scanning electron microscope (SEM) observations reveal three distinct surface morphologies: (1) smooth, (2) rough and irregular, and (3) convoluted and layered. According to a morphological classification scheme proposed previously, the former two morphologies correspond to coal-derived carbon particles, whereas the latter corresponds to oil-derived carbon particles. In terms of the chemical compositions of the particles with different morphologies, as analyzed by energy-dispersive spectroscopy, linear discriminant analysis reveals that the two fuel types can be distinguished. An overall success rate of >90% of reference of morphologically classified material correctly assigned to two groups that are chemically different each other, indicating a relationship between surface morphology and chemical composition. This result suggests that morphological characterization based on conventional SEM observations is useful in identifying the source fuel of SCPs.  相似文献   

The spatial and temporal distributions of spheroidal carbonaceous particles from sediment core samples from industrial cities in Japan and China     

Eri Hirakawa  Akiko Murakami-Kitase  Takamoto Okudaira  Jun Inoue  Hideo Yamazaki  Shusaku Yoshikawa 《Environmental Earth Sciences》2011,64(3):833-840

Spheroidal carbonaceous particles (SCPs) are produced by the high-temperature combustion of fossil fuels and emitted in to the atmosphere. The distribution and concentration of SCPs in sediments have been used as a proxy for the distribution of pollutants emitted to the atmosphere. However, the effect on the distribution of SCPs due to industrial activity at nearby industrial cities is yet to be quantified. To clarify the origin of SCPs of ~20 μm in size that are preserved in sediments, we evaluated the abundance, surface morphology, and chemical composition of SCPs in sediment core samples recovered from industrial cities in Japan (Tokyo, Osaka, and Nagasaki) and China (Beijing), with the cities being located at least ~500 km away from each other. Vertical profiles of SCP concentration in sediment cores from the Japanese cities and Beijing are different, reflecting the contrasting industrial histories of the two countries. The SCPs from different cities show contrasting morphological and chemical characteristics, suggesting that ~20 μm SCPs in sediments from the industrial cities could represent the local combustion history in detail, as the influx of local SCPs is dominant at such sites.  相似文献   

Strain localization in soft rock—a typical rate‐dependent solid: experimental and numerical studies     

A. R. Bhandari  J. Inoue 《国际地质力学数值与分析法杂志》2005,29(11):1087-1107

Strain localization developing inside soft rock specimens is examined through experimental observation and numerical simulation. In the experimental study, soft rock specimens are sheared at different strain rates under plane strain conditions and deformation and strain localization characteristics are analysed. Transition of localization mode from highly localized mode for higher strain rate to distributed and diffused mode of strain localization for lower strain rates was observed. In the numerical study, simulations of plane strain compression tests are carried out at different strain rates by using an overstressed‐type elasto‐viscoplastic model in finite element computations. The role of strain rates on setting gradients of strain fields across shear band is clarified. The probable mechanism for transition of localization mode is discussed. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Probing the cosmic reionization history and local environment of gamma-ray bursts through radio dispersion     

Susumu Inoue 《Monthly notices of the Royal Astronomical Society》2004,348(3):999-1008

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The 2000 April multiwavelength campaign of GRS 1915+105     

Y. Ueda  K. Yamaoka  J.E. Grove  M. McCollough  P. Durouchoux  J. Rodriguez  F. Mirabel  J. Swank  M. Feroci  P. Casella  A.J. Castro-Tirado  C. Sánchez-Fernández  S. Chaty  H. Castaneda  K. Kohno  V. Dhawan  S.A. Trushkin  K. Ebisawa  T. Kotani  H. Inoue 《Astrophysics and Space Science》2001,276(1):25-28

We report results from multiwavelength observations of the microquasarGRS 1915+105 performed during the 2000 April campaign. This is one ofthe biggest campaigns ever made for this source covering the broadband from radio to γ-rays. Multiwavelength light curves compiledfrom all the data reduced up to date and broad band spectra obtainedwith ASCA and RXTE are presented.  相似文献