Liquid bridge contribution to shear behavior of unsaturated soil: modeling and application to a micromechanics model     

Fukushima  Yo  Higo  Yosuke  Matsushima  Takashi  Otake  Yu 《Acta Geotechnica》2021,16(9):2693-2711

Acta Geotechnica - Liquid bridges in unsaturated soils attach to grain contacts and contribute to strengthening microscopic bonding forces, which leads to macroscopic high strength and stiffness...  相似文献   

Fine‐structures of planar deformation features in shocked olivine: A comparison between Martian meteorites and experimentally shocked basalts as an indicator for shock pressure     

Atsushi Takenouchi  Takashi Mikouchi  Takamichi Kobayashi  Toshimori Sekine  Akira Yamaguchi  Haruka Ono 《Meteoritics & planetary science》2019,54(9):1990-2005

We performed shock recovery experiments on an olivine‐phyric basalt at shock pressures of 22.2–48.5 GPa to compare with shock features in Martian meteorites (RBT 04261 and NWA 1950). Highly shocked olivine in the recovered basalt at 39.5 and 48.5 GPa shows shock‐induced planar deformation features (PDFs) composed of abundant streaks of defects. Similar PDFs were observed in olivine in RBT 04261 and NWA 1950 while those in NWA 1950 were composed of amorphous lamellae. Based on the present results and previous studies, the width and the abundance of lamellar fine‐structures increased with raising shock pressure. Therefore, these features could be used as shock pressure indicators while the estimated pressures may be lower limits due to no information of temperature dependence. For Martian meteorites that experienced heavy shocks, the minimum peak shock pressures of RBT 04261 and NWA 1950 are estimated to be 39.5–48.5 GPa and 48.5–56 GPa, respectively, which are found consistent with those estimated by postshock temperatures expected by the presence of brown olivine. We also investigated shock‐recovered basalts preheated at 750 and 800 °C in order to check the temperature effects on shock features. The results indicate a reduction in vitrifying pressure of plagioclase and a pressure increase for PDFs formation in olivine. Further temperature‐controlled shock recovery experiments will provide us better constraints to understand and to characterize various features found in natural shock events.  相似文献   

Best practices for the use of meteorite names in publications     

Philipp R. Heck  Christopher Herd  Jeffrey N. Grossman  Dmitry Badjukov  Audrey Bouvier  Emma Bullock  Hasnaa Chennaoui‐Aoudjehane  Vinciane Debaille  Tasha L. Dunn  Denton S. Ebel  Ludovic Ferrire  Laurence Garvie  Jrme Gattacceca  Matthieu Gounelle  Richard Herd  Trevor Ireland  Emmanuel Jacquet  Robert J. Macke  Tim McCoy  Francis M. McCubbin  Takashi Mikouchi  Knut Metzler  Mathieu Roskosz  Caroline Smith  Meenakshi Wadhwa  Linda Welzenbach‐Fries  Toru Yada  Akira Yamaguchi  Ryan A. Zeigler  Michael Zolensky 《Meteoritics & planetary science》2019,54(7):1397-1400

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Petrological,petrofabric, and oxygen isotopic study of five ungrouped meteorites related to brachinites     

Hikari Hasegawa  Takashi Mikouchi  Akira Yamaguchi  Masahiro Yasutake  Richard C. Greenwood  Ian A. Franchi 《Meteoritics & planetary science》2019,54(4):752-767

Northwest Africa (NWA) 6112, Miller Range (MIL) 090206 (plus its pairs: MIL 090340 and MIL 090405), and Divnoe are olivine‐rich ungrouped achondrites. We investigated and compared their petrography, mineralogy, and olivine fabrics. We additionally measured the oxygen isotopic compositions of NWA 6112. They show similar petrography, mineralogy, and oxygen isotopic compositions and we concluded that these five meteorites are brachinite clan meteorites. We found that NWA 6112 and Divnoe had a c axis concentration pattern of olivine fabrics using electron backscattered diffraction (EBSD). NWA 6112 and Divnoe are suggested to have been exposed to magmatic melt flows during their crystallization on their parent body. On the other hand, the three MIL meteorites have b axis concentration patterns of olivine fabrics. This indicates that the three MIL meteorites may be cumulates where compaction of olivine grains was dominant. Alternatively, they formed as residues and were exposed to olivine compaction. The presence of two different olivine fabric patterns implies that the parent body(s) of brachinite clan meteorites experienced diverse igneous processes.  相似文献   

In-situ survey of nanomolar manganese in seawater using an autonomous underwater vehicle around a volcanic crater at Teishi Knoll,Sagami Bay,Japan     

Takashi Doi  Michiaki Takano  Kei Okamura  Tamaki Ura  Toshitaka Gamo 《Journal of Oceanography》2008,64(3):471-477

We present the results of a chemical survey at a submarine volcano, Teishi Knoll, obtained using a submersible in-situ Mn analyzer (GAMOS) mounted on an autonomous underwater vehicle (AUV) platform. During this survey, high-resolution data of dissolved Mn were obtained in three dimensions in nearly real time. The AUV enabled continuous detailed observations along a preprogrammed pathway, which could not have been performed with conventional CTD hydrocasts. During this observation, anomalously high dissolved Mn concentrations were obtained within the crater, corresponding to high water temperatures. The anomalies might be a hydrothermal signature due to volcanic activity from the crater.  相似文献   

Corrigendum to “Climatological mean and decadal change in surface ocean pCO₂, and net sea–air CO₂ flux over the global oceans” [Deep Sea Res. II 56 (2009) 554–577]     

Taro Takahashi  Stewart C. Sutherland  Rik Wanninkhof  Colm Sweeney  Richard A. Feely  David W. Chipman  Burke Hales  Gernot Friederich  Francisco Chavez  Christopher Sabine  Andrew Watson  Dorothee C.E. Bakker  Ute Schuster  Nicolas Metzl  Hisayuki Yoshikawa-Inoue  Masao Ishii  Takashi Midorikawa  Yukihiro Nojiri  Arne Krtzinger  Tobias Steinhoff  Mario Hoppema  Jon Olafsson  Thorarinn S. Arnarson  Bronte Tilbrook  Truls Johannessen  Are Olsen  Richard Bellerby  C.S. Wong  Bruno Delille  N.R. Bates  Hein J.W. de Baar 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2075-2076

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MOS-1/1b MESSR Observations of the Antarctic Sea Ice: Ice Bands and Ice Streamers     

Kunimitsu Ishida  Kay I. Ohshima  Takashi Yamanouchi  Hiroshi Kanzawa 《Journal of Oceanography》1999,55(3):417-426

Meso- or submeso-scale features of the Antarctic sea ice are investigated using the MOS-1/1b MESSR Images (spatial resolution of approximately 50 m) received at Syowa Station. Particular attention is paid to the ice bands and ice streamers in coastal polynyas. In the Antarctic Ocean, ice bands can be often seen not only at the ice edge but also in the ice interior zone throughout the year and they extend for hundreds of kilometers in the latitudinal direction. It is found that the width and spacing of ice bands tend to decrease from winter to summer. The width of ice band is about 2–6 km in August and September, and 0.1–0.7 km in December. The spacing of ice bands is about 3–10 km in August and September, and 0.1–2 km in December. In coastal polynyas, ice streamers, which are composed of new ice, are sometimes observed. In general, the row of the streamers is spaced at 0.5–2 km with a width of 0.1–1.0 km.  相似文献   

Long-term monitoring of bottom environments of the continental slope off Otsuchi Bay,northeastern Japan     

Kazumasa Oguri  Yasuo Furushima  Takashi Toyofuku  Takafumi Kasaya  Masahide Wakita  Shuichi Watanabe  Katsunori Fujikura  Hiroshi Kitazato 《Journal of Oceanography》2016,72(1):151-166

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Characteristics of ionic components in precipitation in Kitakyushu City,Japan     

Yasuhiro Yamato  Takashi Yamada  Kozo Kido 《Journal of Atmospheric Chemistry》1993,17(4):325-337

Precipitation samples were collected by filtrating bulk sampler in Kitakyushu City, Japan, from January 1988 to December 1990. Volume weighted annual mean of pH was 4.93, but the pH distribution indicated that most probable value lay in the range pH 6.0–6.4. Volume weighted annual mean concentrations of major ionic components were as follows; SO ₄ ^2– : 84.2, NO ₃ ^– : 28.1, Cl^–: 86.3, NH ₄ ⁺ : 45.5, Ca²⁺: 63.3, Mg²⁺: 27.0, K⁺: 3.4, Na⁺: 69.0 µ eq l^–1. The highest concentrations of these ionic components were observed in winter and the lowest occurred in the rainy season. The ratio of ex-SO ₄ ^2– /NO ₃ ^– exhibited the lowest ratio in summer, and the highest ratio in winter. Good correlations were obtained between Cl^– and Na⁺, ex-SO ₄ ²⁺ and ex-Ca²⁺, NO ₃ ^– and ex-Ca²⁺, and NH ₄ ⁺ and ex-SO ₄ ^2– , respectively. However, no correlation between Cl^– and Na⁺ with Ca²⁺ was observed. The relationship of H⁺ with (ex-SO ₄ ^2– + NO ₃ ^– ) - (ex-Ca²⁺ + NH ₄ ⁺ ) indicated positive correlation.  相似文献   

Small scale turbulent diffusion determined with underwater flow visualization     

Takashi Ichiye  James McGrath  Michael Carnes 《Pure and Applied Geophysics》1982,120(4):758-771

Dye plumes were generated at three depths in the seasonal thermocline between 7 and 11 m, 22 km south of Key West on 21 August 1980 and photographed at about 10 second intervals with an underwater camera system. Eleven pairs of consecutive pictures are analyzed to determine the mean current vertical shear and the width of the plumes by positioning reference points relative to the rod attached to the camera system. The relative distances of reference points are calibrated with the stereophotogrammetric method for one pair. The eddy diffusivity is calculated by use of a model of turbulent diffusion developed byTaylor (1921). Its values range from 5 to 25 cm²s^–1 for the plume widths ranging from 33 to 132 cm. The Richardson number is calculated for each pair of pictures with the vertical density gradient estimated from temperature profiles. Its values are higher than the critical value of 0.25 except for one case. The diffusivity was higher by orders of magnitude than the molecular one and indicates the presence of turbulence together with billow like features of the plumes in spite of high Richardson numbers. This suggests that the billow turbulence might be caused by effects of surface gravity waves and not by the Kelvin-Helmholtz instability.  相似文献