Surface circulation in the central Mediterranean Sea as deduced from Lagrangian drifters in the 1990s     

Pierre-Marie Poulain  Enrico Zambianchi 《Continental Shelf Research》2007

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Modelling of ground motion in the vicinity of massive structures     

Claudio Chiaruttini  Stefano Grimaz  Enrico Priolo 《Soil Dynamics and Earthquake Engineering》1996,15(2):75

A two-dimensional elastic Chebyshev spectral element method (SPEM) is used to model the seismic wavefield within a massive structure and in its vicinity. We consider 2-D models where a linear elastic structure, with quadrangular cross-section, resting on an elastic homogeneous half-space, is impinged upon by the waves generated by a surface impulse at some distance. The scattering of Rayleigh waves and the response of the structure are extensively analysed in a parametric way, varying size, mechanical parameters and shape of the load. Some of the models considered are representative of embankments and earth dams. The simulation shows that some models resonate, storing part of the incoming energy. With realistic parameters, the lowest resonance frequency is due to pure shear deformation and is controlled by the shear velocity and height of the load. Flexural modes are excited only at higher frequencies. The acceleration at the top of the structure may be five/seven times higher than at the base, depending on the mass of the structure. The gradual release of trapped energy produces a ground roll lasting several seconds after the wave front has passed. The ground-roll amplitude depends on the sturcture's mass and can be as large as 30% of the peak acceleration. Outside resonance conditions, the ground motion is almost unaffected by the presence of the artefact; the horizontal motion on top of it is nearly twice the motion at ground level. Similar results should be expected when the incident field is an upcoming shear wave. A qualitative discussion shows that the presence of anelastic attenuation in the embankment does not significantly alter the preceding conclusions, unless it is of very low values (e.g. Q < 15).The modelling results that we discuss indicate that the soil-structure interaction may substantially alter the ‘free-field’ ground motion. From a practical point of view, the main conclusions are: (1) careful analysis is necessary when interpreting seismic records collected in the vicinity of large artefacts; (2) seismic hazard at a site may depend on the presence of man-made structures such as embankments, dams, tall and massive buildings.  相似文献   

Effect of some co-dissolved inorganic groups on the photodecomposition of aqueous nitrates     

Enrico G. Gori  Henry M. Papée 《Pure and Applied Geophysics》1969,77(1):201-206

Summary The rate of nitrite formation, in UV-irradiated aqueous solutions of alkali metals, is found to depend on co-dissolved chemical compounds and on their reactivities. The effect of some common and simple components of the atmospheric aerosol is investigated in the laboratory.  相似文献   

On gamma-ray emission from CYG X-2     

Roberto Fusco-Femiano  Enrico Massaro 《Astrophysics and Space Science》1973,25(1):239-245

We discuss the importance of hard X- and gamma-ray emission from thermal X-ray sources to obtain a more realistic picture of these objects.In particular, we show that the inverse Compton effect is a possible mechanism of gamma-ray emission from sources of this kind and apply our consideration to the specific case of Cyg X-2.  相似文献   

The Calabrian Stage redefined     

Maria Bianca Cita Luca Capraro Neri Ciaranfi Enrico Di Stefano Fabrizio Lirer Patrizia Maiorano Maria Marino Isabella Raffi Domenico Rio Rodolfo Sprovieri Simona Stefanelli Gian Battista Vai 《《幕》》2008,31(4):408-419

The name Calabrian was introduced in the geological literature by the French stratigrapher Maurice Gignoux in 1910, and later described in his important monograph （633 pages） ＂Les formations marines pliocknes et quaternaires de l＇ltalie du sud et de la Sicile ＂published in 1913. Detailed data were provided on several sections （Santa Maria di Catanzaro, Caraffa, Monasterace, Palermo） and on their fossil content. The Calabrian Stage has commonly been used for over fifty years as the oldest subdivision of the Qua- ternary, notably in the time scales of Berggren ＆ van Cou- vering （1974） and Haq ＆ Eysinga （1987）. However, after the GSSP for the Pliocene/Pleistocene boundary （P/P） was approved by INQUA in 1982 and ratified by lUGS in 1984 at the Vrica section of Calabria, there was a decline in the usage of the stage name, and an increasing tendency by many Quaternary workers to question the boundary stratotype. This was because there was increasing evidence that it did not correspond to the beginning of the ＂ice age＂. In doing so, they were not complying with the recommendations presented at the 18th International Geological Congress （IGC） in London, 1948 （Oakley, 1950）.  相似文献   

POLARIX: a pathfinder mission of X-ray polarimetry     

Enrico Costa  Ronaldo Bellazzini  Gianpiero Tagliaferri  Giorgio Matt  Andrea Argan  Primo Attinà  Luca Baldini  Stefano Basso  Alessandro Brez  Oberto Citterio  Sergio Di Cosimo  Vincenzo Cotroneo  Sergio Fabiani  Marco Feroci  Antonella Ferri  Luca Latronico  Francesco Lazzarotto  Massimo Minuti  Ennio Morelli  Fabio Muleri  Lucio Nicolini  Giovanni Pareschi  Giuseppe Di Persio  Michele Pinchera  Massimiliano Razzano  Luigia Reboa  Alda Rubini  Antonio Maria Salonico  Carmelo Sgro’  Paolo Soffitta  Gloria Spandre  Daniele Spiga  Alessio Trois 《Experimental Astronomy》2010,28(2-3):137-183

Since the birth of X-ray astronomy, spectral, spatial and timing observation improved dramatically, procuring a wealth of information on the majority of the classes of the celestial sources. Polarimetry, instead, remained basically unprobed. X-ray polarimetry promises to provide additional information procuring two new observable quantities, the degree and the angle of polarization. Polarization from celestial X-ray sources may derive from emission mechanisms themselves such as cyclotron, synchrotron and non-thermal bremsstrahlung, from scattering in aspheric accreting plasmas, such as disks, blobs and columns and from the presence of extreme magnetic field by means of vacuum polarization and birefringence. Matter in strong gravity fields and Quantum Gravity effects can be studied by X-ray polarimetry, too. POLARIX is a mission dedicated to X-ray polarimetry. It exploits the polarimetric response of a Gas Pixel Detector, combined with position sensitivity, that, at the focus of a telescope, results in a huge increase of sensitivity. The heart of the detector is an Application-Specific Integrated Circuit (ASIC) chip with 105,600 pixels each one containing a full complete electronic chain to image the track produced by the photoelectron. Three Gas Pixel Detectors are coupled with three X-ray optics which are the heritage of JET-X mission. A filter wheel hosting calibration sources unpolarized and polarized is dedicated to each detector for periodic on-ground and in-flight calibration. POLARIX will measure time resolved X-ray polarization with an angular resolution of about 20 arcsec in a field of view of 15 × 15 arcmin and with an energy resolution of 20% at 6 keV. The Minimum Detectable Polarization is 12% for a source having a flux of 1 mCrab and 10⁵ s of observing time. The satellite will be placed in an equatorial orbit of 505 km of altitude by a Vega launcher. The telemetry down-link station will be Malindi. The pointing of POLARIX satellite will be gyroless and it will perform a double pointing during the earth occultation of one source, so maximizing the scientific return. POLARIX data are for 75% open to the community while 25% + SVP (Science Verification Phase, 1 month of operation) is dedicated to a core program activity open to the contribution of associated scientists. The planned duration of the mission is one year plus three months of commissioning and SVP, suitable to perform most of the basic science within the reach of this instrument. A nice to have idea is to use the same existing mandrels to build two additional telescopes of iridium with carbon coating plus two more detectors. The effective area in this case would be almost doubled.  相似文献   

Lithosphere density model in Italy: no hint for slab pull     

Enrico Brandmayr  Iginio Marson  Fabio Romanelli  Giuliano Francesco Panza 《地学学报》2011,23(5):292-299

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Ancient synsedimentary structural control on thrust ramp development: an example from the Northern Apennines, Italy     

Enrico Tavarnelli 《地学学报》1996,8(1):65-74

The Umbria-Marche-Sabina foreland fold and thrust belt (Northern Apennines, Italy) provides excellent test-cases for the hypothesis of ancient syndepositional structural features controlling thrust ramp development. The sedimentary cover, Late Triassic to Miocene in age, is made of platform and pelagic carbonates, whose deposition was controlled by significant synsedimentary extension. Normal faulting, mainly during the Jurassic and the Late Cretaceous-Palaeogene, determined sensible lateral thickness variations within the relative sequences. By late Miocene the sedimentary cover was detached from its basement along a mainly evaporitic horizon, and was deformed by means of eastward-verging folds and thrusts.
In order to locate the points where thrust ramps branch-off the basal detachment, both line-length and equal-area techniques were used in the construction of a balanced cross-section through three major fault-related folds in southeastern Umbria. The nucleation of thrust ramps was controlled by the occurrence of Jurassic and Cretaceous-Palaeogene synsedimentary normal faults. These interrupted the lateral continuity of the evaporitic unit (the Late Triassic Anidriti di Burano Fm.) at the base of the sedimentary cover, and acted as obstacles to the eastward propagation of the thrust system, giving rise to major folds which originated from tip-line folding processes.
Therefore, the inferred relationships between ancient normal faults and late thrusts indicate that synsedimentary tectonic structures and the related lateral stratigraphic variations can be envisaged as mechanically important perturbations, which effectively control the nucleation and development of thrust ramps.  相似文献   

Seismic risk assessment and hazard mapping in Nepal     

Chaulagain  Hemchandra  Rodrigues  Hugo  Silva  Vitor  Spacone  Enrico  Varum  Humberto 《Natural Hazards》2015,78(1):583-602

Natural Hazards - Seismic risk in the form of impending disaster has been seen from past records that moderate-to-large earthquakes have caused the loss of life and property in all parts of Nepal....  相似文献   

旋转扰动流体中壁面湍流不稳定及其拟序结构研究Ⅱ：数值模式   总被引：1，自引：1，他引：0  

Enrico Ferrero  张瑛  全利红  Luca Mortarini  Renato Forza 《气象与减灾研究》2009,32(4):14-17

对第一部分的实验结果进行了讨论,指出局地最大、最小涡度的存在与所谓的正压不稳定和大气中经常观测到的滚动涡有关。速度廓线中的拐点和涡度极大值点对应不稳定发展的位置。另外,为了改进湍流的模拟,根据“准正则”近似,发展了一个三阶闭合模式。这个模型已被证明可以描述与湍流过程有关的流体动力学变量的趋势。  相似文献