Nonlinear finite and discrete element simulations of multi-storey masonry walls     

Occhipinti  Giuseppe  Cali&#;  Ivo  D&#;Altri  Antonio Maria  Grillanda  Nicola  de Miranda  Stefano  Milani  Gabriele  Spacone  Enrico 《Bulletin of Earthquake Engineering》2022,20(4):2219-2244

Bulletin of Earthquake Engineering - This paper reports the results of different finite and discrete element simulations on a well-known benchmark of an unreinforced plane masonry structure....  相似文献   

Experimental investigation on sea ripple evolution over sloping beaches     

Carmelo Petrotta  Carla Faraci  Pietro Scandura  Enrico Foti 《Ocean Dynamics》2018,68(9):1221-1237

This paper reports on a wave flume experimental campaign carried out to investigate the appearance, the growth and the migration of small scale bedforms on a sloping sandy bed due to both regular and random waves. A Vectrino Profiler along with a structured light approach were used for velocity and morphodynamic measurements at two positions, one located above the horizontal bed, and the other one above the sloping beach. The velocity was computed by phase averaging the velocity measurements. Several velocity profiles were analyzed, identifying an offshore-directed steady current that extends from few centimeters above the bottom for all the analyzed water column. Ripple geometry was measured by a structured light approach and compared with that predicted by several models to shed light on the effects induced by the sloping beach on the shape and asymmetry. Along the sloping beach, the ripples appeared strongly asymmetric with the onshore half wavelengths smaller than the offshore ones. Finally, ripple geometry and migration triggered by regular waves were compared with those generated by random waves with comparable flow orbital amplitude showing a good agreement.  相似文献   

The influence of structural organization of epilithic and endolithic lichens on limestone weathering          下载免费PDF全文

Mariagrazia Morando  Katrin Wilhelm  Enrica Matteucci  Luca Martire  Rosanna Piervittori  Heather A. Viles  Sergio Enrico Favero‐Longo 《地球表面变化过程与地形》2017,42(11):1666-1679

Hyphal penetration, mineral dissolution and neoformation at the lichen–rock interface have been widely characterized by microscopic and spectroscopic studies, and considered as proxies of lichen deterioration of stone substrates. However, these phenomena have not been clearly related to experimental data on physical properties related to stone durability, and the physical consequences of lichen removal from stone surfaces have also been overlooked. In this study, we combine microscopic and spectroscopic characterization of the structural organization of epi‐ and endolithic lichens (Caloplaca marina (Wedd.) Du Rietz, Caloplaca ochracea (Schaer.) Flagey, Bagliettoa baldensis (A.Massal.) Vězda, Porina linearis (Leight.) Zahlbr., Verrucaria nigrescens Pers.) at the interface with limestones of interest for Cultural Heritage (Portland Limestone, Botticino Limestone), with analysis of rock properties (water absorption, surface hardness) relevant for durability, before and after the removal or scraping of lichen thalli. Observations using reflected‐light and electron microscopy, and Raman analyses, showed lichen–limestone stratified interfaces, differing in the presence/absence and depth of lichen anatomical layers (lithocortex, photobiont layer, pervasive and sparse hyphal penetration component) depending on species and lithology. Specific structural organizations of lichen–rock interface were found to be associated with differential patterns of water absorption increase, evaluated by Karsten tube, in comparison with surfaces with microbial biofilms only, even more pronounced after the removal or scraping of the upper structural layers. Equotip measurements on surfaces bearing intact thalli showed lower hardness in comparison with control surfaces. By contrast, after the removal or scraping procedures, Equotip values were similar to or higher than those of controls, suggesting that the increasing open porosity may be related to a biogenic hardening process. Such counterposed patterns of porosity increase and hardening need to be considered when models relating lichen occurrence on limestones and biogeomorphological surface evolution are proposed, and to evaluate the consequences of lichen removal from stone‐built cultural heritage. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Tethyan heritage in the development of the Neogene Umbria-Marche fold-and-thrust belt, Italy: a 3D approach     

Enrico Tavarnelli 《地学学报》1996,8(5):470-478

The Umbria-Marche fold-and-thrust belt (Northern Apennines, Italy), provides excellent opportunities to evaluate the structural heritage of the opening of the Mesozoic Tethys Ocean in the 3D geometry of the Neogene compressional structures related to the Alpine Orogeny. The structure and evolution of a portion of the southernmost belt, between the Nera River and the Rieti Basin, are described as a field example, and the kinematics along well-exposed Mesozoic extension structures are provided. Cross-section restoration shows a close coincidence between these extension structures and the Neogene thrust ramps, thus suggesting that the geometry of the latter was controlled by the map distribution of the former. Sequential balancing also allows for the definition of the geometrical pattern of pre-existing normal faults, which were produced in response to a unidirectional or a two-directional extension stress field. The inferred direction of principal extension, corrected for the effects of late deformation, is consistent with that proposed for the northern margin of the Adria Promontory in global-scale plate tectonic reconstructions.  相似文献   

Effect of chloride concentration on the decomposition of aqueous sodium nitrate by sunlight     

Gianna L. Petriconi  Enrico G. Gori  Henry M. Papée 《Pure and Applied Geophysics》1969,72(1):299-306

Summary Rates and yields of nitrite formation in solutions, upon irradiation of aqueous sodium nitrate with ultraviolet light, are found to be consistently and considerably enhanced by their chloride content. The process is investigated under conditions met both, in the laboratory and under sunlight illumination, and the effects of altitude and temperature on the reaction studied in the field, are evaluated.  相似文献   

Insights into present-day crustal motion in the central Mediterranean area from GPS surveys   总被引：3，自引：0，他引：3  

Marco Anzidei  Paolo Baldi  Giuseppe Casula  Alessandro Galvani  Enzo Mantovani  Arianna Pesci  Federica Riguzzi  Enrico Serpelloni 《Geophysical Journal International》2001,146(1):98-110

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PAssive COastal TOMography: an Innovative Approach for the Remote Monitoring of Sea Temperature     

Enrico De  Marinis  Paola Picco  Alessandro Crise  Otello Gasparini  Stefano Salon 《Marine Ecology》2002,23(S1):122-137

Abstract. This paper describes a new Ocean Acoustic Tomography (OAT) methodology - a passive tomography - presently in an advanced development phase. This technique has been developed for long-term, extensive, remote monitoring of the seawater temperature spatial distribution, which is estimated from the received noise emitted from ships of opportunity. To test the passive tomographic processor under controlled conditions, the components of the naval noise from different kinds of vessels was analysed and realistic naval noise was simulated. The feasibility of the proposed methodology was confirmed by test-runs on semi-synthetic data; its capability to resolve temperature profiles will be better assessed with the use of real acoustic and environmental data collected during the INTIMATE00 experiment performed in October 2000 in the Atlantic Ocean off the Portuguese coast. An analysis of the space and time variability of the Empirical Orthogonal Function (EOF) decomposition of the sound speed (SSP) in the Mediterranean Sea has been carried out to identify areas where acoustic tomography can be successfully applied. Results from simulations in the South Adriatic Sea, which was identified as a region with a high sound speed variability associated with the seasonal cycle and with the main oceanographic processes, are reported.  相似文献   

Relative motion of the Adriatic with respect to the confining plates: seismological and geodetic constraints   总被引：3，自引：0，他引：3  

Daniele Babbucci  Caterina Tamburelli  Marcello Viti  Enzo Mantovani  Dario Albarello  Francesca D'Onza  Nicola Cenni  Enrico Mugnaioli 《Geophysical Journal International》2004,159(2):765-775

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2-D spectral element simulations of destructive ground shaking in Catania (Italy)     

Enrico Priolo 《Journal of Seismology》1999,3(3):289-309

This study wants to estimate the strong ground motion in the municipal area of Catania (Italy) for a catastrophic earthquake scenario. It is part of a larger research program funded by the National Research Council – National Group for the Defence Against Earthquakes (CNR-GNDT), The Catania Project, devoted to evaluating the seismic risk of a highly urbanised area, such as that of Catania, located in a seismically active region. The reference earthquake simulates the catastrophic event (M 7.2) of 1693. The ground shaking is computed solving the 2-D full-wave equation by the Chebyshev spectral element method (SPEM). Particular emphasis is given to the construction of realistic structural models, also including the finest local detail, obtained from the geophysical, geological and geotechnical data available. Simulations are performed for several sources, to account for both a change in source position and orientation, and the finite extension of the fault along its dip. Synthetic seismograms and peak ground acceleration (PGA) envelopes, calculated at the surface for four transects across the Catania area, constitute the main result of this study which can be used for practical purposes. Simulations show that ground motion is strongly influenced by both source characteristics and crustal structure. We have found that PGA values range between 0.1 g and 0.5 g, although particular site conditions strongly affect these values locally. For example, the frequencies of maximum interest in civil engineering (1.5–4 Hz) are enhanced selectively by a thick portion of surface sediments (i.e., 30–100 m for an average shear wave velocity of 500–600 m/s). An unexpected feature is the appreciable increase of PGA at large epicentral distances, which contradicts classical attenuation relations. All the results are examined through an analysis of the propagating wavefield.  相似文献   

The Serchio River catchment,northern Tuscany: Geochemistry of stream waters and sediments,and isotopic composition of dissolved sulfate     

Gianni Cortecci  Enrico Dinelli  Tiziano Boschetti  Paola Arbizzani  Loredana Pompilio  Mario Mussi 《Applied Geochemistry》2008

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