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141.
Charalambos Mouzakis Chrissy-Elpida Adami Lucia Karapitta Elizabeth Vintzileou 《Bulletin of Earthquake Engineering》2018,16(2):803-829
The present work focuses on the seismic behaviour of timber-laced masonry buildings with timber floors, before and after the application of intervention techniques. A two-storey building with timber ties (scale 1:2) was subjected to biaxial seismic actions. Prior to the execution of shaking table tests, the dynamic characteristics of the model were identified. The base acceleration was increased step-wise until the occurrence of significant but repairable damages. Afterwards, the masonry was strengthened by means of grouting, whereas the diaphragm action of the top floor of the building was enhanced and the model was re-tested. The tests on the timber reinforced model before strengthening show that the presence of timber ties within the masonry elements contributes to improved seismic behaviour. The performance of the model after strengthening shows that the selected intervention techniques led to a significant improvement of the seismic behaviour of the building model. 相似文献
142.
Simone Marri rea Ferrara Lucia Pozzetti 《Monthly notices of the Royal Astronomical Society》2000,317(2):265-272
We derive the expected Type II supernova (SN) differential number counts, N ( m ), and Hubble diagram for SCDM and LCDM cosmological models, taking into account the effects of gravitational lensing (GL) produced by the intervening cosmological mass. The mass distribution of dark matter haloes (i.e. the lenses) is obtained by means of a Monte Carlo method applied to the PressSchechter mass function. The haloes are assumed to have a Navarro, Frenk & White (NFW) density profile, in agreement with recent simulations of hierarchical cosmological models. Up to z =15, the (SCDM, LCDM) models predict a total number of (857, 3656) SNII yr1 in 100 surveyed 44 arcmin2 fields of the Next Generation Space Telescope ( NGST ). NGST will be able to reach the peak of the N ( m ) curve, located at AB 30(31) for SCDM (LCDM) in J and K wavelength bands, and detect (75 per cent, 51 per cent) of the above SN events. This will allow a detailed study of the early cosmic star formation history, as traced by SNIIe. N ( m ) is only very mildly affected by the inclusion of lensing effects. In addition, GL introduces a moderate uncertainty in the determination of cosmological parameters from Hubble diagrams, when these are pushed to higher z . For example, for a 'true' LCDM with (M =0.4, =0.6), without proper account of GL, one would instead derive We briefly compare our results with previous similar work and discuss the limitations of the model. 相似文献
143.
Lucia Luzi Fabio Sabetta Francesco Mele Barbara Castello 《Bulletin of Earthquake Engineering》2010,8(5):1159-1174
The Italian Accelerometic Archive (ITACA) was created in 2007 during a joint project between the Italian Institute for Geophysics
and Vulcanology (Istituto Nazionale di Geofisica e Vulcanologia, INGV) and the Italian Civil Protection (Dipartimento della Protezione Civile, DPC). The project, started in 2006, had the aim of filling the data gap of existing strong motion databases and facilitating
strong motion data users in obtaining good quality waveforms, through the collection, homogenization and distribution of strong
motion data acquired during the period 1972–2004 in Italy by different institutions (Ente Nazionale per l’Energia Elettrica, ENEL, Italian electricity company; Ente per le Nuove tecnologie, l’Energia e l’Ambiente, ENEA, Italian energy and environment organization DPC). The compiled database contains 2,182 three-component waveforms generated
by 1,008 earthquakes with a maximum moment magnitude of 6.9 (1980 Irpinia earthquake) and can be accessed on-line at the portal
denominated ITACA at the site , where a wide range of search tools enables the user to interactively retrieve events, recording stations and waveforms with
particular characteristics, whose parameters can be specified, as needed, through user friendly interfaces. A range of display
options allows users to view data in different contexts, extract and download time series and spectral data. This article
describes the state of the art up to 2006 and the activities which led to the completion of the project. 相似文献
144.
Rosalba Maresca Norma Damiano Lucia Nardone Mauro A. Di Vito Francesca Bianco 《Journal of Seismology》2014,18(3):385-400
In this study, we describe two experiments of seismic noise measurements carried out in Naples, Italy. The site allowed measurements to be obtained both at the surface and in a tunnel that is 120-m-deep. The main goal was to compare the seismic response evaluated at the surface to the in-tunnel response, through spectral, polarization, and resonance directivity analyses. In the 1 to 20 Hz frequency band, the noise level was up to 15 dB higher at the surface than in the tunnel. The polarization properties and horizontal-to-vertical spectral ratios appear not to be influenced by the tunnel geometry or by the topography. Some preferential alignments were observed in the polarization azimuths computed at the surface, which are likely to be due to local sources, rather than morphological features. The absence of directivity effects and the low noise levels in the tunnel make this site suitable for installing seismic stations. We also studied how the subsoil structure affects the seismic motion at the surface. The dispersive properties of the Rayleigh waves were investigated using the spatial autocorrelation method. A joint inversion of the dispersion data and the horizontal-to-vertical spectral ratios provided the subsurface Vs profile. The derived model has a low velocity contrast at depth, such as to generate moderate and broad H/V spectral ratio peak amplitude. The normalized spectral ratio appears more appropriate to identify the soil-resonance frequencies. 相似文献
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147.
The large marine ecosystem (LME) concept and approach has had a global impact on marine ecosystem-based management. The LME approach provides a framework for assessing and monitoring LMEs and is based on five modules: productivity, fish and fisheries, pollution and ecosystem health, socioeconomics, and governance. It appears that the LME approach is also being used to structure interventions to bring about change. Its appropriateness for the latter purpose is questioned. The major concerns are that the LME approach is not consistent with current thinking about enabling governance and its compartmentalized structure does not facilitate effective governance intervention. Current thinking on good governance suggests that it is more appropriate to approach governance interventions at the LME scale through multi-level governance policy cycles. 相似文献
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150.
James M. Dohm Victor R. Baker William V. Boynton Alberto G. Fairén Justin C. Ferris Michael Finch Roberto Furfaro Trent M. Hare Daniel M. Janes Jeffrey S. Kargel Suniti Karunatillake John Keller Kris Kerry Kyeong J. Kim Goro Komatsu William C. Mahaney Dirk Schulze-Makuch Lucia Marinangeli Gian G. Ori Javier Ruiz Shawn J. Wheelock 《Planetary and Space Science》2009,57(5-6):664-684
The Gamma Ray Spectrometer (Mars Odyssey spacecraft) has revealed elemental distributions of potassium (K), thorium (Th), and iron (Fe) on Mars that require fractionation of K (and possibly Th and Fe) consistent with aqueous activity. This includes weathering, evolution of soils, and transport, sorting, and deposition, as well as with the location of first-order geomorphological demarcations identified as possible paleoocean boundaries. The element abundances occur in patterns consistent with weathering in situ and possible presence of relict or exhumed paleosols, deposition of weathered materials (salts and clastic minerals), and weathering/transport under neutral to acidic brines. The abundances are explained by hydrogeology consistent with the possibly overlapping alternatives of paleooceans and/or heterogeneous rock compositions from diverse provenances (e.g., differing igneous compositions). 相似文献