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   

Autonomous underwater vehicle teams for adaptive ocean sampling: a data-driven approach   总被引：1，自引：1，他引：0  

Andrea?MunafòEmail author  Enrico?Simetti  Alessio?Turetta  Andrea?Caiti  Giuseppe?Casalino 《Ocean Dynamics》2011,61(11):1981-1994

The current technological developments in autonomous underwater vehicles (AUVs) and underwater communication have nowadays allowed to push the original idea of autonomous ocean sampling network even further, with the possibility of using each agent of the network not only as an operative component driven by external commands (model-driven) but as a reactive element able to act in response to changing conditions as measured during the exploration (data-driven). With this paper, we propose a novel data-driven algorithm for AUVs team for adaptive sampling of oceanic regions, where each agent shares its knowledge of the environment with its teammates and autonomously takes decision in order to reconstruct the desired oceanic field. In particular, sampling point selection is made in order to minimize the uncertainty in the estimated field while keeping communication contact with the rest of the team and avoiding to repeatedly sampling sub-regions already explored. The proposed approach is based on the use of the emergent behaviour technique and on the use of artificial potential functions (interest functions) to achieve the desired goal at the end of the mission. In this way, there is no explicit minimization of a cost functional at each decision step. The oceanic field is reconstructed by the application of radial basis functions interpolation of irregularly spaced data. A simulative example for the estimation of a salinity field with sea data obtained using the Mediterranean Sea Forecasting System is shown in the paper, in order to investigate the effect of the different uncertainty sources, including sea currents, on the behaviour of the exploration team and ultimately on the reconstruction of the salinity field.  相似文献   

Hazard Evaluation in Valpara��so: the MAR VASTO Project     

Maurizio Indirli  Hoby Razafindrakoto  Fabio Romanelli  Claudio Puglisi  Luca Lanzoni  Enrico Milani  Marco Munari  Sotero Apablaza 《Pure and Applied Geophysics》2011,168(3-4):543-582

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Turbulence-induced steady streaming in an oscillating boundary layer: On the reliability of turbulence closure models     

Luca Cavallaro  Pietro Scandura  Enrico Foti 《Coastal Engineering》2011

The accuracy of several closure models of the Reynolds-Averaged Navier–Stokes Equations in predicting the characteristics of an oscillating turbulent wall boundary layer is analyzed. The analysis involves four low Reynolds number k − ε models and a k − ω model and it is carried out by comparing the model results both with experimental data and with data obtained by a Direct Numerical Simulation (DNS) of the Navier–Stokes equations. The boundary layer is generated by a spatially constant time-oscillating pressure gradient given by the sum of two harmonic components characterized by angular frequencies Ω^∗ and 2Ω^∗ respectively, which generates a steady streaming because of the asymmetry of turbulence intensity during the cycle. Thus the results are relevant to the boundary layer at the bottom of nonlinear sea waves. The attention is therefore focused on the accuracy of the models in reproducing the period averaged profiles of the hydrodynamic characteristics of the steady streaming. The instantaneous quantities, such as time development of the wall shear stress, profiles of the streamwise velocity, Reynolds stresses and turbulent kinetic energy are also considered and analyzed. The results shows that a model can be judged better or worse than other models depending on the specific flow characteristic under investigation. However, an approach has been adopted which allowed to rank the models according to their accuracy in predicting the values of the hydrodynamic quantities involved in the present study.  相似文献   

Rough evaluation of the water-inflow discharge in abandoned mining tunnels using a simplified water balance model: the case of the Cogne iron mine (Aosta Valley, NW Italy)     

Stefano Lo Russo  Loretta Gnavi  Daniele Peila  Enrico Suozzi 《Environmental Earth Sciences》2013,70(6):2753-2765

One of the most complex hydrogeological problems in the design and maintenance of drainage systems in abandoned mining sites is quantifying the maximum water infiltration and, therefore, the amount that is potentially drainable by the tunnels. This problem is compounded when water-inflow data are limited or lacking. The aim of the study was to present a single but reliable model for making this evaluation; this model was applied to the case history of the abandoned Cogne iron ore mining complex (Western Alps, Aosta Valley Region, NW Italy). The study focused on quantifying the amount of water infiltrating into the mine drifts, using a water balance model in a Geographic Information System (GIS) environment. In the model, five different infiltration scenarios were calculated, including a detailed analysis of rainfall data, snow density and thickness (Snow Water Equivalent calculation), and melting periods. The maximum water discharge that could affect the mine tunnels was, therefore, determined under several scenarios of normal precipitation conditions and during heavy rainfall, including the case of the Cogne valley flood in October 2000, used as a reference for the limit conditions. Taking into account the various approximations considered, the results can be considered a good indication of the magnitude of the total amount of water that should be drained out through abandoned mine drifts and in the drainage network during implementation of final closure of the mine.  相似文献   

Dredging displaces bottlenose dolphins from an urbanised foraging patch     

Enrico Pirotta  Barbara Eva Laesser  Andrea Hardaker  Nicholas Riddoch  Marianne Marcoux  David Lusseau 《Marine pollution bulletin》2013

The exponential growth of the human population and its increasing industrial development often involve large scale modifications of the environment. In the marine context, coastal urbanisation and harbour expansion to accommodate the rising levels of shipping and offshore energy exploitation require dredging to modify the shoreline and sea floor. While the consequences of dredging on invertebrates and fish are relatively well documented, no study has robustly tested the effects on large marine vertebrates. We monitored the attendance of common bottlenose dolphins (Tursiops truncatus) to a recently established urbanised foraging patch, Aberdeen harbour (Scotland), and modelled the effect of dredging operations on site usage. We found that higher intensities of dredging caused the dolphins to spend less time in the harbour, despite high baseline levels of disturbance and the importance of the area as a foraging patch.  相似文献   

Geological structure of a long‐living geothermal system,Larderello, Italy     

Giovanni Bertini  Michele Casini  Giovanni Gianelli  Enrico Pandeli 《地学学报》2006,18(3):163-169

We have examined the data of 600 geothermal wells and re‐interpreted approximately 500 km seismic profiles through the field of Larderello, Italy. We conclude that the two main seismic reflectors present below the geothermal area host two different fluids: (1) superheated steam in the upper H‐horizon (reached by drillholes) and (2) supercritical fluid in the deeper K‐horizon (reached by few unproductive or damaged wells). The superheated steam has the physical and chemical connotation of the geothermal fluid exploited so far at Larderello, whereas the supercritical fluid represents a potential unconventional deep‐seated resource still to be assessed. The high temperatures existing in correspondence of the K‐horizon suggest that the silica‐rich rocks are close to a plastic state and the fluids should remain confined in a medium sealed to the confining rocks, unless occasional fluid overpressure and abrupt high strain rates occur.  相似文献   

Quiescent times in gamma-ray bursts – II. Dormant periods in the central engine?     

Enrico Ramirez-Ruiz  rea Merloni  Martin J. Rees 《Monthly notices of the Royal Astronomical Society》2001,324(4):1147-1158

Within the framework of the internal–external shocks model for γ -ray bursts, we study the various mechanisms that can give rise to quiescent times in the observed γ -ray light curves. In particular, we look for the signatures that can provide us with evidence as to whether or not the central engine goes dormant for a period of time comparable to the duration of the gaps. We show that the properties of the prompt γ -ray and X-ray emission can, in principle, determine whether the quiescent episodes are caused by a modulated relativistic wind or a switching off of the central engine. We suggest that detailed observations of the prompt afterglow emission from the reverse shock will strongly constrain the possible mechanisms for the production of quiescent times in γ -ray bursts.  相似文献   

Gamma-ray bursts in normal and extreme star-forming galaxies     

Neil Trentham  Enrico Ramirez-Ruiz  A. W. Blain 《Monthly notices of the Royal Astronomical Society》2002,334(4):983-989

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The River Arno catchment,northern Tuscany: chemistry of waters and sediments from the River Elsa and River Era sub‐basins,and sulphur and oxygen isotopes of aqueous sulphate     

Gianni Cortecci  Enrico Dinelli  Tiziano Boschetti 《水文研究》2007,21(1):1-20

Within the hydrologic balance of the River Arno catchment (northern Tuscany), the Rivers Elsa and Era are important tributaries entering the main river from the left bank in the lower part of the watershed. Waters and bed sediments were sampled in June 2000 during low discharges in the Rivers Elsa and Era, as well as in major tributary streams. Water samples were analysed for major chemistry and sulphur isotope composition of sulphate, and sediment samples were analysed for major composition and selected trace elements of environmental concern (Zn, Cu, Pb, Cr and Ni). The main results for the waters are: (1) Na and Cl in solution show consistent downstream positive trends in the main rivers, thus supporting progressive contributions of anthropogenic salts; the highest concentration values are observed in tributaries; (2) as shown by sulphur isotopes, sulphate in solution is mainly controlled by dissolution of evaporites (Elsa basin) or oxidation of reduced organic/biogenic sulphur (Era basin), with anthropogenic contributions in most streams not higher than 10% in both the basins. A δ³⁴S signature in the range ?2 to +3‰ is estimated for pollutant sulphate in the basins studied. The main results for the sediments are: (1) major chemistry is essentially controlled by the lithotypes drained by the waters; (2) pollution by heavy metals does not reach high levels; (3) compared with local fine‐grained rocks, copper is more frequently anomalous, whereas lead and zinc show only occasional anomalies; (4) local high concentrations of chromium and nickel can be attributed to upstream occurrences of ophiolites. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献