Descent into the Abyss     

Enrico Bonatti 《地学学报》1995,7(6):578-579

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A Lagrangian Decorrelation Time Scale in the Convective Boundary Layer   总被引：1，自引：1，他引：0  

Gervasio Degrazia  Domenico Anfossi  Haroldo Fraga De Campos Velho  Enrico Ferrero 《Boundary-Layer Meteorology》1998,86(3):525-534

A new method for deriving the Lagrangian decorrelation time scales for inhomogeneous turbulence is described. The expression for the time scales here derived for the convective boundary layer is compared to those estimated by Hanna during the Phoenix experiment. Then the values of C₀, the Lagrangian velocity structure function constant, and of B_i, the Lagrangian velocity spectrum constant, were evaluated from the Eulerian velocity spectra and from the Lagrangian time scales derived, under unstable conditions, from Taylor's statistical diffusion theory. The numerical coefficient of the lateral and vertical Lagrangian spectra in the inertial subrange was found equal to 0.21, in good agreement with previous experimental estimates.  相似文献   

Variability of Mediterranean coralligenous assemblages subject to local variation in sediment deposition     

Balata D  Piazzi L  Cecchi E  Cinelli F 《Marine environmental research》2005,60(4):403-421

This study tested whether the development of coralligenous assemblages on horizontal and vertical surfaces differed between localities of high and low sediment deposition. The development and structure of these assemblages varied in predictable ways according to the level of sediment deposition. These differences were largely independent of the orientation of substratum. Turfs were more extensive in areas of high sediment deposition while erect and encrusting algae were most extensive in areas of low sediment deposition. Encrusting invertebrates characterised vertical surfaces and were most extensive in areas of high sediment deposition. These results are consistent with studies from other temperate regions of the globe, suggesting that effects of sedimentation on temperate coasts are substantial and widespread.  相似文献   

Vertical tectonism in oceanic fracture zones     

Enrico Bonatti 《Earth and Planetary Science Letters》1978,37(3):369-379

Anomalous topographic highs are found along many large oceanic fracture zones, frequently in the form of transverse ridges elongated parallel to the fractures both within and outside of the transform zone. These crustal highs are one or more kilometers shallower than the adjacent “normal” crust of equivalent age. Their elevation is frequently higher than the axial zone of lithospheric accretion. Geophysical and petrological data from the Vema, St. Paul, Romanche (Atlantic Ocean), Owen (Indian Ocean), Alula (Gulf of Aden), and other fracture zones suggest that the anomalous transverse ridges are not the result of excess volcanism, but rather of tectonic uplift of upper mantle and crustal blocks.Factors which may determine vertical tectonism along fracture zones include: (1) horizontal thermal conduction across a fracture zone from a lithospheric accreting segment; (2) viscodynamic forces operating in a fracture zone close to its intersection with an accreting segment; and (3) compressional and tensional horizontal stresses operating along a fracture zone, and created by several causes, the major one being small changes in the direction of spreading. Among these various factors, compressional and tensional horizontal stresses are probably the main cause of vertical tectonism in fracture zones. During the vertical motion of upper mantle/crustal blocks, ultramafic rocks, due to their physical properties, are uplifted preferentially.One of the implications of fracture zone vertical tectonism is that the age/depth of the crust relationship may not apply in regions with large fracture zones. In one well-documented case, a transverse crustal block at the Romanche fracture zone subsided during the last 5 m.y. at an average rate more than one order of magnitude faster than crust of equivalent age.  相似文献   

Preliminary tests on large-scale suppression of warm fog by means of giant monodisperse particulates. Part II. An extensive systematic experiment in the Ghedi-Monte Orfano area     

Alberto C. Montefinale  Gianna L. Petriconi  Enrico G. Gori  Henry M. Papee 《Pure and Applied Geophysics》1970,83(1):173-181

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Project ‘climatite’     

Enrico G. Gori  Gianna L. Petriconi  Alberto C. Montefinale  Tito Montefinale  Henry M. Papee 《Pure and Applied Geophysics》1972,99(1):230-250

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Performance of “G-Pisa” ring laser gyro at the Virgo site     

Jacopo Belfi  Nicolò Beverini  Filippo Bosi  Giorgio Carelli  Angela Di Virgilio  Dmitri Kolker  Enrico Maccioni  Antonello Ortolan  Roberto Passaquieti  Fabio Stefani 《Journal of Seismology》2012,16(4):757-766

The ring laser gyroscope ??G-Pisa?? has been taking data inside the Virgo interferometer central area with the aim of performing high sensitivity measurements of rotations in the vertical as well as in the horizontal orientation. We discuss the main characteristics of the instrument, describing its mechanical design and presenting the measured sensitivity limit. By applying a simple effective model for the laser gyroscope, we show that the stability of the sensor above 10?s of integration time is mainly limited by backscattering effects. The horizontal rotation rate signal is also compared with the signals recorded by the Virgo environmental monitoring system and by a biaxial mechanical tiltmeter rigidly fixed on top of the gyrolaser mounting frame.  相似文献   

Advanced frame element for seismic analysis of masonry structures: model formulation and validation          下载免费PDF全文

Eva Raka  Enrico Spacone  Vincenzo Sepe  Guido Camata 《地震工程与结构动力学》2015,44(14):2489-2506

This paper presents a masonry panel model for the nonlinear static and dynamic analysis of masonry buildings suitable for the seismic assessment of new and existing structures. The model is based on an equivalent frame idealization of the structure and stems from previous research on force‐based frame elements. The element formulation considers axial, bending, and shear deformations within the framework of the Timoshenko beam theory. A phenomenological cyclic section law that accounts for the shear panel response is coupled, through equilibrium between shear and bending forces along the element, with a fiber‐section model that accounts for the axial and bending responses. The proposed panel model traces with a low computational burden and numerical stability the main aspects of the structural behavior of masonry panels and is suitable for analyses of multi‐floor buildings with a relatively regular distribution of openings and with walls and floors organized to grant a box‐like behavior under seismic loads. The model capabilities are validated though analyses of simple unreinforced masonry panels and comparisons with published experimental results. The model accuracy is strongly dependent on the fiber and shear constitutive laws used. However, the formulation is general, and laws different from those employed in this study are easily introduced without affecting the model formulation. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Earthquake loss estimation for the Kathmandu Valley     

Hemchandra Chaulagain  Hugo Rodrigues  Vitor Silva  Enrico Spacone  Humberto Varum 《Bulletin of Earthquake Engineering》2016,14(1):59-88

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Seismic safety assessment of existing masonry infill structures in Nepal     

Hemchandra Chaulagain  Hugo Rodrigues  Enrico Spacone  Humberto Varum 《地震工程与工程振动(英文版)》2016,15(2):251-268

Reinforced concrete (RC) buildings in Nepal are constructed with RC frames and masonry infill panels. These structures exhibit a highly non-linear inelastic behavior resulting from the interaction between the panels and frames. This paper presents an extensive case study of existing RC buildings in Nepal. Non-linear analyses were performed on structural models of the buildings considered as a bare frame and with masonry infill, in order to evaluate the influence of infill walls on the failure mechanisms. Five three-storey buildings with different structural configurations and detailing were selected. The effect of masonry infill panels on structural response was delineated by comparing the bare-framed response with the infill response. Seismic performance is evaluated with regard to global strength, stiffness, energy dissipation, inter-storey drift, and total deflection of the structure. A parametric analysis of structures with masonry infill is also performed. For this, the influence of different material properties is studied, namely diagonal compressive stress, modulus of elasticity and tensile stress of masonry infill panels. Study results show that masonry infill increases the global strength and stiffness of the structures; it decreases the inter-storey drift and hence the total displacement of the structure. The results quantify the influence of the infill panels on structural response and, in particular, the effect of the diagonal compressive strength of the masonry wall.  相似文献