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排序方式: 共有321条查询结果,搜索用时 15 毫秒
301.
Building damage scenarios based on exploitation of Housner intensity derived from finite faults ground motion simulations 总被引:2,自引:2,他引:0
Leonardo Chiauzzi Angelo Masi Marco Mucciarelli Marco Vona Francesca Pacor Giovanna Cultrera Frantisek Gallovič Antonio Emolo 《Bulletin of Earthquake Engineering》2012,10(2):517-545
In this paper earthquake damage scenarios for residential buildings (about 4200 units) in Potenza (Southern Italy) have been
estimated adopting a novel probabilistic approach that involves complex source models, site effects, building vulnerability
assessment and damage estimation through Damage Probability Matrices. Several causative faults of single seismic events, with
magnitude up to 7, are known to be close to the town. A seismic hazard approach based on finite faults ground motion simulation
techniques has been used to identify the sources producing the maximum expected ground motion at Potenza and to generate a
set of ground motion time histories to be adopted for building damage scenarios. Additionally, site effects, evaluated in
a previous work through amplification factors of Housner intensity, have been combined with the bedrock values provided by
hazard assessment. Furthermore, a new relationship between Housner and EMS-98 macroseismic intensity has been developed. This
relationship has been used to convert the probability mass functions of Housner intensity obtained from synthetic seismograms
amplified by the site effects coefficients into probability mass function of EMS-98 intensity. Finally, the Damage Probability
Matrices have been applied to estimate the damage levels of the residential buildings located in the urban area of Potenza.
The proposed methodology returns the full probabilistic distribution of expected damage, thus avoiding average damage index
or uncertainties expressed in term of dispersion indexes. 相似文献
302.
Rocchetti L Beolchini F Hallberg KB Johnson DB Dell'Anno A 《Marine pollution bulletin》2012,64(8):1688-1698
We investigated changes of prokaryotic diversity during bioremediation experiments carried out on anoxic marine sediments characterized by high hydrocarbon and metal content. Microcosms containing contaminated sediments were amended with lactose and acetate and incubated in anaerobic conditions up to 60 d at 20 or 35 °C. Microcosms displaying higher degradation efficiency of hydrocarbons were characterized by the dominance of Alphaproteobacteria and Methanosarcinales and the lack of gene sequences belonging to known hydrocarbonoclastic bacteria. Multivariate analyses support the hypothesis that Alphaproteobacteria are important for hydrocarbon degradation and highlight a potential synergistic effect of archaea and bacteria in changes of metal partitioning. Overall, these results point out that the identification of changes in the prokaryotic diversity during bioremediation of contaminated marine sediments is not only important for the improvement of bio-treatment performance towards hydrocarbons, but also for a better comprehension of changes occurring in metal partitioning which affect their mobility and toxicity. 相似文献
303.
Giacomo Colombatti Alessio Aboudan Francesca Ferri Francesco Angrilli 《Planetary and Space Science》2008,56(5):601-612
During the first phase of Huygens arrival into Titan's atmosphere the probe is subjected to gravitational and aerodynamic forces in aerodynamic hypersonic regime. Atmospheric drag exerts a strong deceleration on the capsule measured by Huygens atmospheric structure instrument (HASI) servo accelerometer. A 6 DOF (Degree of Freedom) model of the Huygens probe entry dynamics has been developed and used for data analysis. The accelerometer data are analysed and the model allows the retrieval of dynamics information of Huygens probe from 1545 km altitude down to end of the entry phase. Probe's initial conditions (velocity and position) were refined to match the measured deceleration profile resulting in a different altitude at interface epoch with respect to those of the Cassini Navigation Team. Velocity and position of probe at interface epoch are compatible with those used by Descent Trajectory Working Group (DTWG).Measurements acquired before atmosphere detection are used to estimate probe's angular rate, bound attitude and characterise the angle of attack profile which results to be lower than 4° during the whole entry. Probe's spin calculated (6.98 RPM) is slightly different with respect to DTWG of 7.28 RPM but considering a 2% error in the Inertia matrix these results are inside the 1-σ error band. 相似文献
304.
305.
Francesca Bruno Daniela Cocchi Fedele Greco Elena Scardovi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(5):1235-1245
Rainfall is a phenomenon difficult to model and predict, for the strong spatial and temporal heterogeneity and the presence of many zero values. We deal with hourly rainfall data provided by rain gauges, sparsely distributed on the ground, and radar data available on a fine grid of pixels. Radar data overcome the problem of sparseness of the rain gauge network, but are not reliable for the assessment of rain amounts. In this work we investigate how to calibrate radar measurements via rain gauge data and make spatial predictions for hourly rainfall, by means of Monte Carlo Markov Chain algorithms in a Bayesian hierarchical framework. We use zero-inflated distributions for taking zero-measurements into account. Several models are compared both in terms of data fitting and predictive performances on a set of validation sites. Finally, rainfall fields are reconstructed and standard error estimates at each prediction site are shown via easy-to-read spatial maps. 相似文献
306.
307.
Simone Recchi Francesca Matteucci Annibale D'Ercole 《Monthly notices of the Royal Astronomical Society》2001,322(4):800-820
We study the effect of a single, instantaneous starburst on the dynamical and chemical evolution of a gas-rich dwarf galaxy, the potential well of which is dominated by a dark matter halo. We follow the dynamical and chemical evolution of the interstellar medium (ISM) by means of an improved two-dimensional hydrodynamical code coupled with detailed chemical yields originating from type II SNe, type Ia SNe and single low- and intermediate-mass stars (IMS). In particular we follow the evolution of the abundances of H, He, C, N, O, Mg, Si and Fe. We find that for a galaxy resembling IZw18, a galactic wind develops as a consequence of the starburst and it carries out of the galaxy mostly the metal-enriched gas. In addition, we find that different metals are lost differentially in the sense that the elements produced by type Ia SNe are lost more efficiently than others. As a consequence of that, we predict larger [ α /Fe] ratios for the gas inside the galaxy than for the gas leaving the galaxy. A comparison of our predicted abundances of C, N, O and Si in the case of a burst occurring in a primordial gas shows a very good agreement with the observed abundances in IZw18 as long as the burst has an age of ∼31 Myr and IMS produce some primary nitrogen. However, we cannot exclude that a previous burst of star formation had occurred in IZw18, especially if the pre-enrichment produced by the older burst was lower than Z =0.01 Z⊙ . Finally, at variance with previous studies, we find that most of the metals reside in the cold gas phase already after a few Myr. This result is mainly caused by the assumed low SN II heating efficiency, and justifies the generally adopted homogeneous and instantaneous mixing of gas in chemical evolution models. 相似文献
308.
Giorgio Boni Luca Ferraris Francesca Giannoni Giorgio Roth Roberto Rudari 《Advances in water resources》2007
A methodology is proposed for the inference, at the regional and local scales, of flood magnitude and associated probability. Once properly set-up, this methodology is able to provide flood frequencies distributions at gauged and un-gauged river sections pertaining to the same homogeneous region, using information extracted from rainfall observations. A proper flood frequency distribution can be therefore predicted even in un-gauged watersheds, for which no discharge time series is available. 相似文献
309.
Camuffo Dario della Valle Antonio Becherini Francesca 《Theoretical and Applied Climatology》2018,132(3-4):1143-1151
Theoretical and Applied Climatology - Surface wetness is a synergistic factor to determine atmospheric corrosion, monument weathering, mould growth, sick buildings, etc. However, its detection and... 相似文献
310.
The green–blue swing: plasticity of plankton food‐webs in response to coastal oceanographic dynamics
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Domenico D'Alelio Maria Grazia Mazzocchi Marina Montresor Diana Sarno Adriana Zingone Iole Di Capua Gayantonia Franzè Francesca Margiotta Vincenzo Saggiomo Maurizio Ribera d'Alcalà 《Marine Ecology》2015,36(4):1155-1170
The internal organization of plankton communities plays a key role in biogeochemical cycles and in the functioning of aquatic ecosystems. In this study, the structure of a marine plankton community (including both unicellular and multicellular organisms) was inferred by applying an ecological network approach to species abundances observed weekly at the long‐term ecological research station MareChiara (LTER‐MC) in the Gulf of Naples (Tyrrhenian Sea, Mediterranean Sea) in the summers of 2002–2009. Two distinct conditions, characterized by different combination of salinity and chlorophyll values, alternated at the site: one influenced by coastal waters, herein named ‘green’, and the other reflecting more offshore conditions, named ‘blue’. The green and blue ‘phases’ showed different keystone biological elements: namely, large diatoms and small‐sized flagellates, respectively. Several correlations amongst species belonging to different trophic groups were found in both phases (connectance ~0.30). In the green phase, several links between phytoplankton and mesozooplankton and within the latter were detected, suggesting matter flow from microbes up to carnivorous zooplankton. A microbial‐loop‐like sub‐web, including mixo‐ and heterotrophic dinoflagellates and ciliates, was present in the green phase, but it was relatively more important in the blue phase. The latter observation suggests a more intense cycling of matter at the microbial trophic level in the blue phase. These results show that different modes of ecological organization can emerge from relatively small changes in the composition of aquatic communities coping with environmental variability. This highlights a significant plasticity in the internal structure of plankton webs, which should be taken into account in predictions of the potential effects of climatic oscillations on aquatic ecosystems and biogeochemical cycles therein. 相似文献