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The purpose of this study is the evaluation of dynamic behavior induced by seismic activity on a silo system, containing bulk material, with a soil foundation. The interaction effects between the silo and bulk material, as well as the effects produced between the foundation of the silo and the soil, were taken into account. Proposed simplified approximation, as well as the finite model, were used for analysis. The results, from the presented approximation, were compared with a more rigorous obtainment method. Initially, the produced simplified approximation, with elastic material assumption for the grain, could determine the pressures on the dynamic material along with displacements along the height of the silo wall and base shear force, etc., with remarkable precision. Some comparisons, via a change of soil and/or foundation conditions, were also made regarding the seismic pressure of the dynamic material pressure, displacement and base shear forces for both squat and slender silos. Comparing the analytical predictions to results from the numerical simulations produced good results. It can be concluded that the model can be used effectively to perform a broad suite of parametric studies, not only at the design stage but also as a reliable tool for predicting system behavior under the limit state of the system. The results and comprehensive analysis show that displacement effects and base shear forces generally decreased when soil was softer; however, soil structure interaction (SSI) did not have any considerable effects on squat silos and therefore need not be taken into practice. 相似文献
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P. Cristofanelli P. di Carlo A. D’. Altorio C. Dari Salisburgo P. Tuccella F. Biancofiore P. Stocchi G. P. Verza T. C. Landi A. Marinoni F. Calzolari R. Duchi Paolo Bonasoni 《Pure and Applied Geophysics》2013,170(11):1985-1999
Tropospheric ozone (O3) is an important atmospheric pollutant and climate forcer. The Mediterranean basin is a hot-spot region in terms of short-term O3 distribution, with frequent episodes of high tropospheric O3, especially during summer. To improve the characterisation of summer O3 variability in the Mediterranean area, during the period 6–27 August 2009 an experimental campaign was conducted at Campo Imperatore, Mt Portella (CMP), a high mountain site (2,388 m a.s.l.) located in the central Italian Apennines. As deduced from analysis of atmospheric circulation, the measurement site was significantly affected by air masses originating over the Mediterranean basin, which affected the measurement site for 32 % of the time. Analysis of average values and diurnal and day-to-day variability revealed that CMP O3 observations (average value 60.0 ± 5.1 ppbv) were comparable with measurements at other European mountain stations, indicating a prevalent effect of meteorological conditions and atmospheric transport on the synoptic scale. In fact, only a small “reverse” diurnal variation typically characterises diurnal O3 variability because of local thermal wind circulation, which sporadically favours transport of air masses rich in O3 from the foothill regions. Statistical analysis of five-day back-trajectory ensembles indicates that synoptic-scale air-mass transport from the Mediterranean Sea usually results in decreasing O3 concentrations at CMP, whereas the highest hourly O3 values are mostly associated with air masses from central continental Europe, eastern Europe, and northern Italy. High O3 concentrations are also related to downward air-mass transport from higher altitudes. Comparison of in-situ O3 variability with tropospheric O3 satellite-based measurements reveals similar features of the two data sets. Together with the results from back-trajectory analysis, this indicates that CMP measurements might usefully improve characterisation of broad-scale O3 variability over the central Mediterranean basin. 相似文献
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ＳｔａｔｉｃｓｏｌｕｔｉｏｎｏｆａｃｒａｃｋｄｅｇｅｎｅｒａｔｅｄｆｒｏｍｄｙｎａｍｉｃｓｏｌｕｔｉｏｎｏｆａｐｒｏｐａｇａｔｉｎｇｃｒａｃｋＳｈｉ－ＹｕＬＩ（李世愚）ａｎｄＹｕｎ－ＴａｉＣＨＥＮ（陈运泰）（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ... 相似文献
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《Journal of Atmospheric and Solar》2002,64(15):1667-1673
Clúa de Gonzales et al. (J. Atmos. Terr. Phys. 63 (2001) 367) analyzed the monthly means of the geomagnetic aa-index available since 1868 and found enhanced geomagnetic activity in July outside of the known seasonal course of semiannual variation. They pointed out that this behavior is mainly caused by the high values of the geomagnetic activity. Their analysis confirmed results obtained from an analysis of Ap-values nearly 30 years ago but widely unknown to the scientific community. At that time the entire year was analyzed using running means of the activity values averaged to the same date. Aside from the July period, the calculations revealed distinct deviations from the seasonal course—called geomagnetic singularities. The most marked singularity occurs from the middle of March to the end of March characterized by a strong increase from, on average, relatively calm values to the actually strongest ones during the entire year. Some typical time patterns around and after equinox are repeated half a year later. An analysis in 1998 on the basis of the available aa-values confirmed the findings derived from Ap-values and the local activity index Ak from Niemegk, Germany available since 1890. The new results will be presented and discussed. Special attention is paid to the statistical problem of the persistence of geomagnetic perturbations. The main problem under consideration is that the variation of the mean activity is not caused by an accidental accumulation of strong perturbations occurring within certain intervals of days. We assume that the most marked variations of the mean value are not accidental and result from internal processes within the earth's atmosphere but different, particularly small-scale features, are most probably accidental. 相似文献
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TÓMAS JÓHANNESSON 《水文科学杂志》2013,58(3):417-434
Abstract Observations from the jökulhlaup from Grímsvötn in Vatnajökull, south-eastern Iceland, in 1996 indicate that the jökulhlaup was initiated by the movement of a localised pressure wave that travelled 50 km in 10 h from Grimsvötn to the terminus, forming a subglacial pathway along the glacier bed. Shortly after this wave reached the terminus, the jökulhlaup was flowing at a high discharge through a tunnel that would have needed much longer time to form by ice melting as assumed in existing theories of jökulhlaups. Frozen sediments formed in crevasses and frazil ice on the surface of the flood waters indicate the flow of supercooled water in the terminus region, demonstrating that the rate of heat transfer from subglacial flood water to the overlying ice is greatly underestimated in current theories. 相似文献
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V. V. Shcherbakova G. V. Zhidkov V. P. Shcherbakov 《Izvestiya Physics of the Solid Earth》2008,44(10):816-821
A large volume of data on the paleointensity H an obtained by A.S. Bol’shakov and G.M. Solodovnikov is ignored in modern reconstructions because the authors did not indicate whether they used the check-point procedure for the detection of chemical alterations in rocks associated with determination of H an. The paper presents new values of H an determined by the Thellier-Coe method with the use of the checkpoint procedure from samples of the Armenian collection of Cretaceous rocks used in published studies of Bol’shakov and Solodovnikov. The new results are close to the published ones and point to a small value of the geomagnetic field in the Cretaceous, thereby corroborating Bol’shakov-Solodovnikov’s hypothesis on a low paleofield in the Mesozoic. Our study of samples of the collection studied confirms the reliability of Bol’shakov-Solodovnikov’s determinations of H an. 相似文献
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Triploporella ? edgelli n. sp., a new Dasycladalean alga from the Lower Cretaceous of Lebanon 
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下载免费PDF全文 The Dasycladalean assemblage of the Jezzinian strata (uppermost Barremian–lowermost Aptian) of Lebanon consists of two organo‐genera and eight genera with eleven species, including eight Triploporellaceae. Although Triploporella marsicana (Praturlon, 1964) was reported by Saint‐Marc from the same interval, it is not found in our material. However, a lookalike, which is herein described as Triploporella ? edgelli n. sp., is identified. This new species has cyst‐containers within the primary segments of its laterals but, because it lacks calcified secondary segments, it is left in open nomenclature. 相似文献
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An earthquake is regarded as a fracture from the viewpoint of continuum mechanics, in which stress and strain play key roles in understanding the nature of a seismic source. This review briefly outlines the mechanics of a seismic source in terms of the dislocation model and crack model. The introduction includes the Coulomb failure criterion, static stress drop, dynamic stress drop, the Griffith criterion, and the scaling of source parameters. The selection of topics in the introduction emphasizes the application of seismic data, i.e., in practice, the mechanical parameters introduced here are measurable in the interpretation and analysis of seismic waveform data. 相似文献
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J. E. Geisler 《地球物理与天体物理流体动力学》2013,107(1-2):249-272
Abstract This paper describes the linear response of an inviscid two‐layer model of a deep ocean on an f‐plane to a hurricane translating across the surface at constant speed. The forcing is a localized, radially‐symmetric pattern of positive wind stress curl and negative pressure anomaly. Only the steady state response is considered. The principal result is the identification of an internal wake in the lee of the storm, present when the translation speed of the storm exceeds the baroclinic long wave speed. The amplitude of the wake depends on the length of time over which the stress is experienced at a given point. The angle of the wedge filled by the wake is small, an effect due to the fact that the scale of a hurricane is typically larger than the baroclinic radius of deformation. After the wake disperses, a geostrophically balanced baroclinic ridge remains along the storm track. 相似文献
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《国际泥沙研究》2002,(4)
I. Soil erosion and sediment yield Upland Erosion Modeling with CASC2D-SED Pierre JULIEN and Rosal韆 ROJAS (No. 4, pp. 265-274) Effects of Soil Crusting on Soil Moisture, Runoff and Erosion: Field Observations Tongxin ZHU (No. 4, pp. 298-303) II. Environmental and ecological sedimentation Numerical Study on Environmental Impacts of the Third Shanghai Sewerage Project Cheng LIU, Huiran WANG, Y… 相似文献
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《国际泥沙研究》2001,16(4)
I. Soil erosion and sediment yieldDevelopment of Soil Erosion Index Model in Taiwan WatershedsVol. 16, No. 1, pp. 80-90 Modeling of Sediment Yield and Nonpoint Source Pollutant YieldVol. 16, No. 3, pp. 416-420 Runoff Generation Characteristics in Typical Erosion Regions on the Loess PlateauVol. 16, No. 4, pp. 473-485II. Environmental and ecological sedimentationLong Term Effects of Rehabilitation Measures on Bed Load Transport at the Salzach River Vol. 16, No. 2, pp. 95-102 Th… 相似文献
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《国际泥沙研究》2004,(4)
1. Soil erosion and sediment yieldAssessment of Soil Loss on Uncultivated Slope Land by Using 137Cs Techniquein the Upper Yangtze River Basin of China Mingyi FENG, Xinbao ZHANG, Anbang WEN and Xiubin HE (No. 1, pp. 60-65)Evaluation of Erosion Productivity Impact Calculator (EDIC) Model forMIDDLE Mountain Region of Nepal Sohan Kumar GHIMRE and Mukand Singh BABEL (No. 2, pp. 106-122)Rill Ero… 相似文献
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《国际泥沙研究》2005,20(4):366-367
I. Soil Erosion and Sediment Yield Downslope Erosion Process under Upslope Runoff and Sediment Using a Dual-Box System Peiqing Xiao, Fenli Zheng and Wenyi Yao (No. 2, pp. 136-142) Modeling Ephemeral Gully Erosion for Conservation Planning George R. FOSTER (No. 3, pp. 157-175) Hydrologically Driven Mechanisms of Headcut Development M. J. M. R?MKENS and S. N. PRASAD (No. 3, pp. 176-184) Numerical Simulation of Head-cut with a Two-layered Bed Yafei JIA, Tadanori KITAM… 相似文献
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The statistical mechanics of earthquakes adopts the concepts and methodology of statistical mechanics, especially the theory of critical phenomena, in studying the preparation, initiation, propagation and healing of earthquake rupture, which forms a new branch in the physics of seismic source in recent years. This article introduces to the fundamental concepts of the statistical mechanics of earthquakes. The introduction includes the seismic Hamiltonian, percolation model, earthquake rupture nucleation, and Burridge-Knopoff spring-block model. It is pointed out that some of the statistical mechanical models of earthquakes have a sound seismological basis. There is a smooth "transition" from the "classical" theory to the "modern" theory of seismic source. 相似文献
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NUCTECH is a worldwide leading company specialized in research & development of x-ray inspection technology, as well as system design, manufacture, engineering and customer service. With the radiation imaging technology as its core competence, NUCTECH founded in July 1997, is a prestigious high-tech company originated from Tsinghua University. NUCTECH has developed and produced the THSCANTM Container/Vehicle Inspection Systems with linear accelerators, the Air Cargo/Vehicle Sec… 相似文献
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A method of estimation of occurrence probability of earthquake intensity at a given site from the results of a ten-year scale of earthquake prediction described with a probability of occurrence in a given "prediction cell" is proposed in this paper. 2316 cities and towns in China were analyzed by using this method. The probability of intensity Ⅵ-Ⅸ were given for every city. These results can be used for the earthquake insurance, loss estimation, and planning of disaster protection. 相似文献