201 research outputs found

    La messa in sicurezza dell'area industriale di Priolo-Augusta rispetto ai rischi da terremoto e maremoto

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    I recenti forti terremoti che hanno interessato zone particolarmente industrializzate in Turchia ed in India (terremoto del 17.8.1999, Kocaeli, Turchia, Mw = 7.4; e terremoto di Guyarat, India, del 26.01.2001, Mw =7.7) hanno messo in evidenza che al danno prodotto dal terremoto si pu\uf2 aggiungere quello dovuto alle conseguenze di incidenti e/o rotture negli impianti, cosiddetti, \u201ca rischio di incidente rilevante\u201d. Il rischio totale nell\u2019area pu\uf2 quindi assumere valori estremamente elevati in termini economici, ambientali, e talvolta con perdita di vite umane. Ad esempio, nel caso del terremoto turco, il danneggiamento della raffineria Tupras di IZMIT ha provocato l\u2019incendio della stessa e la fuoriuscita di una quantit\ue0 rilevante di olio (Foto 1). Sulla base di quanto sopra e di quanto conosciuto, il presente studio si propone come elemento di base per l\u2019impostazione di interventi strutturali sugli impianti e sul territorio con l\u2019obiettivo di mettere il tutto in condizioni di sicurezza a fronte del terremoto (ed eventuale maremoto associato) atteso nell\u2019area. A questo scopo \ue8 stata realizzata un\u2019analisi per mettere in evidenza l\u2019entit\ue0 e la frequenza dei fenomeni naturali (terremoti e maremoti) che possono determinare significativi impatti sia sull\u2019ambiente fisico che su quello antropizzato (infrastrutture) nell\u2019area di Priolo-Augusta. Il progetto ha avuto come obiettivo iniziale la valutazione dei carichi dovuti a fenomeni naturali che, trasformati in termini ingegneristici, devono essere utilizzati per la verifica della idoneit\ue0 progettuale degli impianti industriali presenti nelle aree studiate. In particolare \ue8 stato valutato, dapprima, il terremoto di riferimento per la progettazione, in termini di picco massimo di accelerazione e spettro di risposta associato. In tale fase si \ue8 anche provveduto alla costruzione di scenari associati ad un eventuale maremoto. I siti prescelti sono esposti ad un elevato rischio sismico la cui definizione ha richiesto l\u2019adozione delle metodologie pi\uf9 avanzate disponibili. A tale scopo sono stati applicati diversi approcci innovativi sia di tipo sismologico che ingegneristico

    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

    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

    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

    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
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