SZ scaling relations in Galaxy Clusters: Results from hydrodynamical N-body simulations     

António J.C. da Silva 《Astrophysics and Space Science》2004,290(1-2):167-176

Observations with the SZ effect constitute a powerful new tool for investigating clusters and constraining cosmological parameters. Of particular interest is to investigate how the SZ signal correlates with other cluster properties, such as the mass, temperature and X-ray luminosities. In this presentation we quantify these relations for clusters found in hydrodynamical simulations of large scale structure and investigate their dependence on the effects of radiative cooling and pre-heating.  相似文献   

Determination of oxadiazon residues in the field treated soil with and without organic matter incorporated     

Kassio Ferreira Mendes  Marcelo Rodrigues dos Reis  Ana Beatriz Rocha de Jesus Passos  Miriam Hiroko Inoue  Antônio Alberto Silva  Daniel Valadão Silva 《Environmental Earth Sciences》2016,75(3):222

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Out‐of‐plane behaviour of a full scale stone masonry façade. Part 2: shaking table tests     

Alexandre A. Costa  António Arêde  Alfredo Campos Costa  Andrea Penna  Aníbal Costa 《地震工程与结构动力学》2013,42(14):2097-2111

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Seismic analysis of a building block     

Nuno Neves  António Arêde  Aníbal Costa 《Bulletin of Earthquake Engineering》2012,10(1):235-267

This paper reports on the study of the seismic response of an urban building block located in Faial, a town of the Horta Island of the Azores, Portugal. The work fits within the framework of studying strengthening schemes suitable for the reconstruction process of a town damaged by an earthquake action and includes numerical modelling of all the building blocks with calibration of material and structural parameters based on ambient vibration tests. The study aims at understanding a number of issues that are likely to influence the global behaviour of the block and the local response of individual buildings, namely the group effect of adjacent constructions, the in-plane stiffness of floors and/or roofs and the presence of possible localized strengthening interventions in selected parts of the block.  相似文献   

Simulation of masonry out‐of‐plane failure modes by multi‐body dynamics          下载免费PDF全文

Alexandre A. Costa  Andrea Penna  António Arêde  Aníbal Costa 《地震工程与结构动力学》2015,44(14):2529-2549

The seismic assessment of the local failure modes in existing masonry buildings is currently based on the identification of the so‐called local mechanisms, often associated with the out‐of‐plane wall behavior, whose stability is evaluated by static force‐based approaches and, more recently, by some displacement‐based proposals. Local mechanisms consist of kinematic chains of masonry portions, often regarded as rigid bodies, with geometric nonlinearity and concentrated nonlinearity in predefined contact regions (unilateral no‐tension behavior, possible sliding with friction). In this work, the dynamic behavior of local mechanisms is simulated through multi‐body dynamics, to obtain the nonlinear response with efficient time history analyses that directly take into account the characteristics of the ground motion. The amplification/filtering effects of the structure are considered within the input motion. The proposed approach is validated with experimental results of two full‐scale shaking‐table tests on stone masonry buildings: a sacco‐stone masonry façade tested at Laboratório Nacional de Engenharia Civil and a two‐storey double‐leaf masonry building tested at European Centre for Training and Research in Earthquake Engineering (EUCENTRE). Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

A Variable Mesh Spacing for Large-Eddy Simulation Models in the Convective Boundary Layer     

Gervásio Annes Degrazia  Umberto Rizza  Franciano Scremin Puhales  Antônio Gledson Goulart  Jonas Carvalho  Guilherme Sausen Welter  Edson Pereira Marques Filho 《Boundary-Layer Meteorology》2009,131(2):277-292

A variable vertical mesh spacing for large-eddy simulation (LES) models in a convective boundary layer (CBL) is proposed. The argument is based on the fact that in the vertical direction the turbulence near the surface in a CBL is inhomogeneous and therefore the subfilter-scale effects depend on the relative location between the spectral peak of the vertical velocity and the filter cut-off wavelength. From the physical point of view, this lack of homogeneity makes the vertical mesh spacing the principal length scale and, as a consequence, the LES filter cut-off wavenumber is expressed in terms of this characteristic length scale. Assuming that the inertial subrange initial frequency is equal to the LES filter cut-off frequency and employing fitting expressions that describe the observed convective turbulent energy one-dimensional spectra, it is feasible to derive a relation to calculate the variable vertical mesh spacing. The incorporation of this variable vertical grid within a LES model shows that both the mean quantities (and their gradients) and the turbulent statistics quantities are well described near to the ground level, where the LES predictions are known to be a challenging task.  相似文献   

Spatial structure of the evolution of surface temperature (1951–2004)     

Pedro M. A. Miranda  António R. Tomé 《Climatic change》2009,93(1-2):269-284

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Mechanics of thick-skinned Variscan overprinting of Cadomian basement (Iberian Variscides)     

António Ribeiro  José Munhá  António Mateus  Paulo Fonseca  Eurico Pereira  Fernando Noronha  José Romão  José Rodrigues  Paulo Castro  Carlos Meireles  Narciso Ferreira 《Comptes Rendus Geoscience》2009,341(2-3):127-139

Remnants of the Cadomian basement can be found in the Iberian Variscides (IBVA) in several key sectors of its autochthonous units (composed of Neoproterozoic to Lower Palaeozoic metasedimentary sequences) and within the Continental Allochthonous Terrane (CAT). Comprehensive characterization of these critical exposures shows that the prevailing features are related to major geological events dated within the age range of 620–540 Ma. Indeed, near the Cambrian–Ordovician boundary, the IBVA Internal Zones experienced pervasive basement thinning and cover thickening, reflecting diffusive displacement of intracratonic rifting that continued until Lower Devonian times. In the thick-skinned Internal Zones, Helvetic/Penninic style nappes were generated, whereas flower upright axial structures developed along transpressive, intraplate shear zones. These features contrast with those preserved in the thin-skinned IBVA External Zones, dominated by décollements above (un-)deformed Palaeozoic and Cadomian basement. The inferred attenuation of rheological contrast between Cadomian basement and Palaeozoic cover can be explained by inherited fabrics due to thermal softening operated during the Cambrian–Lower Devonian extensional regime. Deeper décollements (and subsequent strain partitioning) are also expected to develop at the upper-lower crust (and at the Moho?) transition, as imaged by the available seismic profiling and MT surveys. The whole data implies a significant discontinuity between Cadomian and Variscan Cycles that should have constrained subsequent lithospheric evolution.  相似文献   

Embankments on Soft Soil Reinforced with Stone Columns: Numerical Analysis and Proposal of a New Design Method   总被引：5，自引：1，他引：4  

José Leitão Borges  Tiago Sabino Domingues  António Silva Cardoso 《Geotechnical and Geological Engineering》2009,27(6):667-679

A parametric study of an embankment on soft soils reinforced with stone columns is performed using a computer program based on the finite element method. The cylindrical unit cell formulation is used by modeling one column and its surrounding soft soil with confined axisymmetric behaviour. The computer program incorporates the Biot consolidation theory (coupled formulation of the flow and equilibrium equations) with constitutive relations simulated by the p–q–θ critical state model. The following parameters are analysed: the replacement area ratio, the deformability of the column material, the thickness of the soft soil, the deformability of the fill and the friction angle of the column material. Based on the results of this study, a new design method is proposed, relating the settlement improvement factor to the two factors that revealed major influence: the replacement area ratio and the ratio between the deformability of the soft soil and the deformability of the column material.  相似文献   

A simplified methodology for the seismic assessment of masonry buildings with RC slabs     

Jorge M. Proença  António S. Gago  Filipa Chaves 《Bulletin of Earthquake Engineering》2018,16(1):377-395

The present paper aims to contribute to the knowledge concerning the seismic assessment of load bearing masonry buildings with reinforced concrete slabs. The final goal of the present research was to propose a simple, yet accurate, methodology to assess the seismic safety of existing masonry buildings. The methodology here presented was based on the so-called ICIST/ACSS methodology with major improvements such as the extension to load bearing masonry wall buildings and the consideration of the effects of one of the most common strengthening solutions for masonry walls, here referred to as reinforced plastering mortar, as well as the possibility of considering four levels of increasing refinement: global, by alignment, by wall panel and by wall element. An extended research was performed on the existing methodologies to evaluate the seismic structural risk of load bearing masonry buildings, briefly describing methodologies similar to the one proposed, namely all of those that have in common the fact that they are based in the physical comparison between the resisting and acting shear forces at all storeys and along the two orthogonal horizontal directions. A case study is presented to check the applicability of the proposed methodology. The case study showed that the proposed methodology is relatively simple to apply and has a sufficiently good accuracy when compared with alternative methodologies. The degree of refinement of the analysis (global, by alignment, by wall panel and by wall element) must be taken into consideration and successively more complex analyses may be required when the results of simpler analyses are inconclusive.  相似文献