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21.
Malarvannan G Takahashi S Ikemoto T Isobe T Kunisue T Sudaryanto A Miyagi T Nakamura M Yasumura S Tanabe S 《Marine pollution bulletin》2011,63(5-12):541-547
Two species of fishes (n=52; tilapia and mullet) from industrialized and urbanized areas of Okinawa Island (Manko-Noha river, Hija river and Shikaza river) and from a remote area of Ishigaki Island (Anparu mudflat), Japan were collected between August 2005 and July 2006, and analyzed for five organochlorine compounds (OCs), viz., DDTs, PCBs, CHLs, HCHs and HCB. Concentrations and the contamination patterns of OCs in fishes varied between locations. Considerable residue levels of OCs, especially CHLs and DDTs were found in both fishes from the main Okinawa Island. These levels were relatively higher than the reported values for seafood from Japanese coasts, indicating that even now pollution sources of these contaminants still exist in this region. On the other hand, lower concentrations of OCs were detected in fishes from Ishigaki Island waters than those of other Japanese coastal waters, suggesting that this region is less contaminated by OC contaminants. 相似文献
22.
This paper presents an upscaling concept of swelling/shrinking processes of a compacted bentonite/sand mixture, which also applies to swelling of porous media in general. A constitutive approach for highly compacted bentonite/sand mixture is developed accordingly. The concept is based on the diffuse double layer theory and connects microstructural properties of the bentonite as well as chemical properties of the pore fluid with swelling potential. Main factors influencing the swelling potential of bentonite, i.e. variation of water content, dry density, chemical composition of pore fluid, as well as the microstructures and the amount of swelling minerals are taken into account. According to the proposed model, porosity is divided into interparticle and interlayer porosity. Swelling is the potential of interlayer porosity increase, which reveals itself as volume change in the case of free expansion, or turns to be swelling pressure in the case of constrained swelling. The constitutive equations for swelling/shrinking are implemented in the software GeoSys/RockFlow as a new chemo‐hydro‐mechanical model, which is able to simulate isothermal multiphase flow in bentonite. Details of the mathematical and numerical multiphase flow formulations, as well as the code implementation are described. The proposed model is verified using experimental data of tests on a highly compacted bentonite/sand mixture. Comparison of the 1D modelling results with the experimental data evidences the capability of the proposed model to satisfactorily predict free swelling of the material under investigation. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
23.
Michel Villeneuve Jean-Jacques Cornée Agus Harsolumakso Rossana Martini et Louisette Zaninetti 《Eclogae Geologicae Helvetiae》2005,98(2):297-310
Resume. De nombreuses échelles stratigraphiques de l’?le de Timor ont vu le jour car les corrélations stratigraphiques étaient rendues
difficiles par la complexité tectonique de l’?le et par la variété des faciès. Dès les premiers travaux, plusieurs séries
ont été distinguées, regroupées en trois unités litho-structurales principales: unité allochtone, sub-autochtone et autochtone.
Les données stratigraphiques et géodynamiques récentes montrent que l’?le de Timor est en fait constituée par six unités litho-structurales,
chacune témoignant d’un épisode majeur de l’histoire géologique de l’Ile. Cette histoire consiste d’abord à la séparation,
au Jurassique, d’un bloc issu du continent de Gondwana (unité para-allochtone) qui est entré en collision avec l’arc volcanique
asiatique à l’Oligo-Miocène (unités allochtone et sub-allochtone). Cet ensemble a ensuite été séparé de l’Asie lors de l’ouverture
de la mer de Banda sud, au Miocène supérieur (unité sub-autochtone) pour finalement entrer en collision avec la marge nord
australienne au cours du Pliocène moyen (plateforme australienne et groupe de Kolbano). Timor est depuis incorporée à la marge
nord australienne (unité autochtone).
Ce travail présente les différentes échelles stratigraphiques de chaque nouvelle unité, des propositions de corrélations et
une comparaison avec les ?les voisines de Sumba et de Sulawesi pour aboutir à une proposition d’évolution géodynamique.
Manuscrit re?u le 13 février 2004 Révision acceptée le 14 février 2005 相似文献
24.
Soil–water characteristic curves were obtained for a number of Singapore residual soil samples. Soil samples were obtained from the two main residual soil formations, the Jurong sedimentary formation and the Bukit Timah granitic formation, at various depths. The effect of weathering on the shape of the soil–water characteristic curve is examined. As the test procedure in obtaining the soil–water characteristic curve is tedious and time-consuming, empirical relationships based on multivariate analysis relating the parameters of the Fredlund and Xing (1994) soil–water characteristic curve equation to basic soil properties are suggested for the Singapore residual soils. The multivariate equations were found to be suitable for providing a quick preliminary estimate of the soil–water characteristic curve of Singapore residual soils. 相似文献
25.
Yo-ichiro Otofuji Sadao Sasajima Susumu Nishimura Agus Dharma Fred Hehuwat 《Earth and Planetary Science Letters》1981,54(2):272-280
Paleomagnetic results from the northern arm of Sulawesi show that the arm has been subjected to a clockwise rotation of more than 90° and that its rotational motion began no later than the middle Miocene. The mean direction showing a normal polarity at the Eocene to the early Miocene isD = 98.0° andI = 6.9°. A declination value ofD = 50.1° obtained from Miocene rocks indicates a transition stage of the rotational motion. The datum from Plio-Pleistocene volcanics isD = ?4.6° andI = ?9.3°. This suggests that the rotational motion terminated before the initiation of volcanic activity during the Plio-Pleistocene. 相似文献
26.
Pascale Bouruet-Aubertot Yannis Cuypers Bruno Ferron Denis Dausse Olivier Ménage Agus Atmadipoera Indra Jaya 《Ocean Dynamics》2018,68(7):779-800
Microstructure measurements were performed along two sections through the Halmahera Sea and the Ombai Strait and at a station in the deep Banda Sea. Contrasting dissipation rates (??) and vertical eddy diffusivities (K z ) were obtained with depth-averaged ranges of \(\sim [9 \times 10^{-10}-10^{-5}]\) W kg??1 and of \(\sim [1 \times 10^{-5}-2 \times 10^{-3}]\) m2 s??1, respectively. Similarly, turbulence intensity, \(I={\epsilon }/(\nu N^{2})\) with ν the kinematic viscosity and N the buoyancy frequency, was found to vary seven orders of magnitude with values up to \(10^{7}\). These large ranges of variations were correlated with the internal tide energy level, which highlights the contrast between regions close and far from internal tide generations. Finescale parameterizations of ?? induced by the breaking of weakly nonlinear internal waves were only relevant in regions located far from any generation area (“far field”), at the deep Banda Sea station. Closer to generation areas, at the “intermediate field” station of the Halmahera Sea, a modified formulation of MacKinnon and Gregg (2005) was validated for moderately turbulent regimes with 100 < I < 1000. Near generation areas marked by strong turbulent regimes such as “near field” stations within strait and passages, ?? is most adequately inferred from horizontal velocities provided that part of the inertial subrange is resolved, according to Kolmogorov scaling. 相似文献
27.
太平洋-印度洋贯穿流南海分支在卡里马塔海峡的十年观测回顾 总被引：5，自引：2，他引：3
Wei Zexun Li Shujiang Susanto R. Dwi Wang Yonggang Fan Bin Xu Tengfei Sulistiyo Budi Adi T. Rameyo Setiawan Agus Kuswardani A. Fang Guohong 《海洋学报(英文版)》2019,38(4):1-11
除印度尼西亚贯穿流之外,南海贯穿流也是太平洋向印度洋输送海水的重要分支。尽管基于数值模拟等方法的研究早已指出,南海分支在太平洋-印度洋洋际交换中有重要作用,但是直到2007年之前,南海分支在卡里马塔海峡处的观测几乎是空白。本文回顾了自2007年起,通过中印尼合作项目"南海-印度尼西亚海水交换及对鱼类季节性洄游的影响（SITE）"在卡里马塔海峡开展的近十年观测,以及在此基础上进一步开展的"印度尼西亚贯穿流海域水交换、内波和混合观测及其生态效应（TIMIT）"观测项目,并对SITE和TIMIT观测取得的成果进行了总结。 相似文献
28.
Relocation of hypocenters from DOMERAPI and BMKG networks: a preliminary result from DOMERAPI project 
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下载免费PDF全文 Mohamad Ramdhan Sri Widiyantoro Andri Dian Nugraha Jean-Philippe Métaxian Asep Saepuloh Said Kristyawan Andry Syaly Sembiring Agus Budi Santoso Antoine Laurin Ahmad Ali Fahmi 《地震科学（英文版）》2017,30(2):67-79
Merapi volcano located in central Java, Indonesia, is one of the most active stratovolcanoes in the world. Many Earth scientists have conducted studies on this volcano using various methods. The geological features around Merapi are very attractive to be investigated because they have been formed by a complex tectonic process and volcanic activities since tens of millions of years ago. The southern mountain range, Kendeng basin and Opak active fault located around the study area resulted from these processes. DOMERAPI project was conducted to understand deep magma sources of the Merapi volcano comprehensively. The DOMERAPI network was running from October 2013 to mid-April 2015 by deploying 46 broad-band seismometers around the volcano. Several steps, i.e., earthquake event identification, arrival time picking of P and S waves, hypocenter determination and hypocenter relocation, were carried out in this study. We used Geiger’s method (Geiger 1912) for hypocenter determination and double-difference method for hypocenter relocation. The relocation result will be used to carry out seismic tomographic imaging of structures beneath the Merapi volcano and its surroundings. For the hypocenter determination, the DOMERAPI data were processed simultaneously with those from the Agency for Meteorology, Climatology and Geophysics (BMKG) seismic network in order to minimize the azimuthal gap. We found that the majority of earthquakes occurred outside the DOMERAPI network. There are 464 and 399 earthquakes obtained before and after hypocenter relocation, respectively. The hypocenter relocation result successfully detects some tectonic features, such as a nearly vertical cluster of events indicating a subduction-related backthrust to the south of central Java and a cluster of events to the east of Opak fault suggesting that the fault has an eastward dip. 相似文献
29.
Taufiq Ahmad Hosono Takahiro Ide Kiyoshi Kagabu Makoto Iskandar Irwan Effendi Agus J. Hutasoit Lambok M. Shimada Jun 《Hydrogeology Journal》2018,26(4):1263-1279
In the Bandung basin, Indonesia, excessive groundwater pumping caused by rapid increases in industrialization and population growth has caused subsurface environmental problems, such as excessive groundwater drawdown and land subsidence. In this study, multiple hydrogeochemical techniques and numerical modeling have been applied to evaluate the recharge processes and groundwater age (rejuvenation). Although all the groundwater in the Bandung basin is recharged at the same elevation at the periphery of the basin, the water type and residence time of the shallow and deep groundwater could be clearly differentiated. However, there was significant groundwater drawdown in all the depression areas and there is evidence of groundwater mixing between the shallow and deep groundwater. The groundwater mixing was traced from the high dichlorodifluoromethane (CFC-12) concentrations in some deep groundwater samples and by estimating the rejuvenation ratio (R) in some representative observation wells. The magnitude of CFC-12 concentration, as an indicator of young groundwater, showed a good correlation with R, determined using 14C activity in samples taken between 2008 and 2012. These correlations were confirmed with the estimation of vertical downward flux from shallower to deeper aquifers using numerical modeling. Furthermore, the change in vertical flux is affected by the change in groundwater pumping. Since the 1970s, the vertical flux increased significantly and reached approximately 15% of the total pumping amount during the 2000s, as it compensated the groundwater pumping. This study clearly revealed the processes of groundwater impact caused by excessive groundwater pumping using a combination of hydrogeochemical methods and modeling.
相似文献30.
Rainwater infiltration during typhoons tends to trigger slope instability. This paper presents the results of a study on slope
response to rainwater infiltration during heavy rainfall in a mountain area of Taiwan. The Green-Ampt infiltration model is
adopted here to study the behavior of rainwater infiltration on slopes. The failure mechanism of infinite slope is chosen
to represent the rainfall-induced shallow slope failure. By combining rain infiltration model and infinite slope analysis,
the proposed model can estimate the occurrence time of a slope failure. In general, if a slope failure is to happen on a slope
covered with low permeability soil, failure tends to happen after the occurrence of the maximum rainfall intensity. In contrast,
slope failure tends to occur prior to the occurrence of maximum rainfall intensity if a slope is covered with high-permeability
soil. To predict the potential and timing of a landslide, a method is proposed here based on the normalized rainfall intensity
(NRI) and normalized accumulated rainfall (NAR). If the actual NAR is higher than the NAR calculated by the proposed method,
slope failure is very likely to happen. Otherwise, the slope is unlikely to fail. The applicability of the proposed model
to occurrence time and the NAR–NRI relationship is evaluated using landslide cases obtained from the literature. The results
of the proposed method are close to that of the selected cases. It verifies the applicability of the proposed method to slopes
in different areas of the world.
An erratum to this article can be found at 相似文献