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Cesare Emiliani Eric B. Kraus Eugene M. Shoemaker 《Earth and Planetary Science Letters》1981,55(3):317-334
A paleoecological analysis of the fossil record before and after the Cretaceous/Tertiary boundary indicates that the widespread extinctions and biological stresses around the boundary are best explained in terms of a sudden, significant, but short temperature rise. L. Alvarez and co-authors, having found an enrichment in iridium at the same boundary, postulated that it was associated with the impact of an extraterrestrial body. If this body struck the ocean, the water injected into the atmosphere may have led to a transient increase in the global surface temperature. This temperature pulse may have been primarily responsible for the effects observed in the biosphere. The pattern of extinction of higher plant species suggests that splash down occurred in the northern Pacific-Bering Sea area. 相似文献
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Domenico Antonio De Luca Cesare Comina Manuela Lasagna Enrico Destefanis Luciano Masciocco Alberto Godio Stefano Stocco 《Environmental Earth Sciences》2018,77(1):19
Aquifer overexploitation is a common problem in drinking water management. This will become more and more important given the general reduction of water resources. To overcome overexploitation, one of the most adopted solutions is the relocation of extraction wells. To establish the positions of new wells, a precise knowledge of the hydrogeological setting is required. Specific surveys are therefore necessary to obtain information over wide investigation zones. Geophysical methods, particularly electromagnetic and electrical, can be useful with this aim. In the present paper a case history on the combined use of Electric Resistivity Tomography and Time Domain Electromagnetic soundings is reported. Surveys have been performed within the Maggiore and Traversola Valleys, to investigate the uppermost part of the Quaternary deposits, hosting the near surface aquifer. The electromagnetic data have been inverted with a spatially constrained approach by assuming a quasi 1D model of the subsurface. Geophysical surveys allowed for depicting the depth and lateral continuity of the supposed aquifer level in the surveyed area up to a depth of about 200 m and proposing potential positions for well relocation. 相似文献
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Antonio Di Cesare Felice Carlo Ponzo Domenico Nigro 《Bulletin of Earthquake Engineering》2014,12(6):2777-2796
The advantages of passive supplemental dampers for performance enhancement of new and existing structures have been demonstrated extensively in the past. The big amount of experimental tests carried out all over the world on framed structures upgraded by energy dissipating bracing (EDB) systems based on hysteretic dampers (HDs), have shown their effectiveness in reducing seismic effects on buildings. The mechanical characteristics of the HDs in some cases may be different from those arising by the design procedure due to industrial tolerance or because of some damage suffered during previous earthquakes. In order to assess the robustness of this technique, in terms of capacity of seismic vibrations control even for significant changes in the mechanical characteristics of the EDB system respect to the design ones, in this paper experimental tests and parametric nonlinear time history analysis have been carried out changing the characteristics of the HD stiffness and strength. The experimental results refer to the shaking table tests performed at the Structural Laboratory of the University of Basilicata within a wide research program, named Joint Experimental Testing on Passive and semiActive Control Systems. The program has been completely funded by the Italian Department of Civil Protection within the activity of the Research Line 7 of the ReLUIS (Italian Network of University Laboratories of Earthquake Engineering) 2005–2008 project. A displacement-focused design procedure has been considered to evaluate the mechanical characteristics of the dissipating system, with the aim of limiting inter-storey drifts after frame yielding. From the experimental point of view, two design solutions have been tested for chevron braces equipped with HD, assuming the same stiffness but different values of both ductility demand and yield strength of the HDs. Moreover, parametric studies have been performed through numerical simulations. This paper provides an overview of the experimental set up and briefly summarizes the experimental outcomes and the comparison with the results of numerical nonlinear time history analysis. Moreover, the results of the parametric analysis for the assessment of the performances of the dissipating system in controlling structural response are presented. 相似文献
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Manzini Federico Crippa Roberto Oldani Virgino Guaita Cesare 《Earth, Moon, and Planets》1999,87(2):73-85
Using a CCD camera attached to the 0.335 m and 0.20 m reflectors of S.A.S. Observatory (Novara, Italy), we followed the linear
jets and shells of comet Hale–Bopp between May 1996 and May 1997. In addition to confirming the model of Sekanina and Bohenhardt
(1997), the study of the linear jets provided indications concerning the orientation of the comet's axis of rotation over
time. The study of the shells revealed that the speed at which they move away from the nucleus was not constant. A periodic
variation of the shell expansion velocity may not be excluded : if so, a possible precessional effect on the axis of rotation
of the comet's nucleus could explain this behavior.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Sebastiano Foti Fabrice Hollender Flora Garofalo Dario Albarello Michael Asten Pierre-Yves Bard Cesare Comina Cécile Cornou Brady Cox Giuseppe Di Giulio Thomas Forbriger Koichi Hayashi Enrico Lunedei Antony Martin Diego Mercerat Matthias Ohrnberger Valerio Poggi Florence Renalier Deborah Sicilia Valentina Socco 《Bulletin of Earthquake Engineering》2018,16(6):2367-2420
Surface wave methods gained in the past decades a primary role in many seismic projects. Specifically, they are often used to retrieve a 1D shear wave velocity model or to estimate the VS,30 at a site. The complexity of the interpretation process and the variety of possible approaches to surface wave analysis make it very hard to set a fixed standard to assure quality and reliability of the results. The present guidelines provide practical information on the acquisition and analysis of surface wave data by giving some basic principles and specific suggestions related to the most common situations. They are primarily targeted to non-expert users approaching surface wave testing, but can be useful to specialists in the field as a general reference. The guidelines are based on the experience gained within the InterPACIFIC project and on the expertise of the participants in acquisition and analysis of surface wave data. 相似文献
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