76 research outputs found

    Recorded Motions of the Mw6.3 April 6, 2009 L’Aquila (Italy) Earthquake and Implications for Building Structural Damage: Overview.

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    The normal-faulting earthquake of 6 April 2009 in the Abruzzo Region of central Italy caused heavy losses of life and substantial damage to centuriesold buildings of significant cultural importance and to modern reinforcedconcrete- framed buildings with hollow masonry infill walls. Although structural deficiencies were significant and widespread, the study of the characteristics of strong motion data from the heavily affected area indicated that the short duration of strong shaking may have spared many more damaged buildings from collapsing. It is recognized that, with this caveat of shortduration shaking, the infill walls may have played a very important role in preventing further deterioration or collapse of many buildings. It is concluded that better new or retrofit construction practices that include reinforcedconcrete shear walls may prove helpful in reducing risks in such seismic areas of Italy, other Mediterranean countries, and even in United States, where there are large inventories of deficient structures.Published651-6844.1. Metodologie sismologiche per l'ingegneria sismicaJCR Journalreserve

    Hawking emission from quantum gravity black holes

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    We address the issue of modelling quantum gravity effects in the evaporation of higher dimensional black holes in order to go beyond the usual semi-classical approximation. After reviewing the existing six families of quantum gravity corrected black hole geometries, we focus our work on non-commutative geometry inspired black holes, which encode model independent characteristics, are unaffected by the quantum back reaction and have an analytical form compact enough for numerical simulations. We consider the higher dimensional, spherically symmetric case and we proceed with a complete analysis of the brane/bulk emission for scalar fields. The key feature which makes the evaporation of non-commutative black holes so peculiar is the possibility of having a maximum temperature. Contrary to what happens with classical Schwarzschild black holes, the emission is dominated by low frequency field modes on the brane. This is a distinctive and potentially testable signature which might disclose further features about the nature of quantum gravity.Comment: 36 pages, 18 figures, v2: updated reference list, minor corrections, version matching that published on JHE

    On the modelling of infilled RC frames through strut models

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    Infill panels largely affect the seismic response of framed constructions. The wide variety in their mechanical and geometrical features has produced many different models and assumptions in their analytical representation. In this paper the simplest and most diffuse analytical approach, based on the introduction of equivalent struts, has been checked. An overview is presented, focusing on the strut dimensions, strength and number. Two case-studies, taken by two different experimental campaigns, have been considered and reproduced. The obtained results have been compared to the experimental ones, and some parameters have been checked for selecting the model to use for analysis

    Projeto cartográfico e implementação de um protótipo de atlas escolar interativo

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    Este trabalho tem por objetivo apresentar o desenvolvimento de um protótipo de Atlas Escolar Interativo para alunos do 4º ciclo do ensino fundamental. A abordagem metodológica baseou-se na teoria de desenvolvimento cognitivo com a finalidade de produzir um material que possa ser compreendido e utilizado pelo público alvo. Para tanto, analisou-se as necessidades dos usuários com base nos Parâmetros Curriculares Nacionais relacionados à disciplina de Geografia e nos livros didáticos utilizados em algumas escolas do ensino fundamental. Além disso, aplicou-se recursos multimídia de animação e interatividade, de acordo com a teoria de comunicação cartográfica, para facilitar a leitura e compreensão de mapas e assim, o conhecimento dos fenômenos geográficos. O desenvolvimento do protótipo subdividiu-se em duas grandes etapas: projeto cartográfico e produção do Atlas. Para a implementação do Atlas utilizou-se os aplicativos Macromedia Flash MX, Visual Basic e a biblioteca MapObjects-ESRI. Embora o Atlas não tenha sido avaliado, vale ressaltar que foi projetado com base no conhecimento teóricometodológico do desenvolvimento cognitivo, e é importante que no futuro, esse produto seja testado com um grupo de alunos do referido ciclo para avaliar a real contribuição da animação e interatividade no ensino da Geografia

    Self-force: Computational Strategies

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    Building on substantial foundational progress in understanding the effect of a small body's self-field on its own motion, the past 15 years has seen the emergence of several strategies for explicitly computing self-field corrections to the equations of motion of a small, point-like charge. These approaches broadly fall into three categories: (i) mode-sum regularization, (ii) effective source approaches and (iii) worldline convolution methods. This paper reviews the various approaches and gives details of how each one is implemented in practice, highlighting some of the key features in each case.Comment: Synchronized with final published version. Review to appear in "Equations of Motion in Relativistic Gravity", published as part of the Springer "Fundamental Theories of Physics" series. D. Puetzfeld et al. (eds.), Equations of Motion in Relativistic Gravity, Fundamental Theories of Physics 179, Springer, 201

    Hawking Radiation from Higher-Dimensional Black Holes

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    We review the quantum field theory description of Hawking radiation from evaporating black holes and summarize what is known about Hawking radiation from black holes in more than four space-time dimensions. In the context of the Large Extra Dimensions scenario, we present the theoretical formalism for all types of emitted fields and a selection of results on the radiation spectra. A detailed analysis of the Hawking fluxes in this case is essential for modelling the evaporation of higher-dimensional black holes at the LHC, whose creation is predicted by low-energy models of quantum gravity. We discuss the status of the quest for black-hole solutions in the context of the Randall-Sundrum brane-world model and, in the absence of an exact metric, we review what is known about Hawking radiation from such black holes

    Strength and stiffness reduction factors for infilled frames with openings

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    Framed structures are usually infilled with masonry walls. These may cause significant increase in both stiffness and strength, reducing the deformation demand and increasing the energy dissipation capacity of the system. On the other hand, irregular arrangements of the masonry panels may lead to the concentration of damage in some regions, with negative effects, like for example soft storey mechanisms and shear failures in short columns. Therefore, the presence of infill walls should not be neglected, especially in regions of moderate and high seismicity. To this aim, simple models are available for solid infills walls, such as the diagonal no-tension strut model, while infilled frames with openings have not been investigated adequately. In the present study the effect of openings on strength and stiffness of infilled frames is studied by means of about 150 experimental and numerical tests. The main parameters involved are identified and a simple model to take into account the openings in the infills is developed and compared with other models proposed by different researchers. The model, which is based on the use of strength and stiffness reduction factors, takes into account the opening dimensions and presence of reinforcing elements around the opening. An example of application of the proposed reduction factors is also presented

    Experimental investigation of energy damping in masonry mechanisms

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    Severe earthquakes throughout the world show that existing masonry buildings are prone to suffer out-of-plane local-collapse mechanisms. In such mechanisms energy dissipation is mainly due to impacts against the remainder of the structure. Using data from an experimental campaign on free-rocking walls, estimation are suggested for the coefficient of restitution in both two-sided (façade resting on a foundation) and one-sided (façade adjacent to transverse walls) rocking. Both brick and tuff elements are considered, and the relevance of test repetition and wall height-to-thickness ratio is addressed
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