Assessment of different methods for characterization and simulation of post-cracking behavior of self-compacting steel fiber reinforced concrete

The post-cracking tensile properties of steel fiber reinforced concrete (SFRC) is one of the most important aspects that should be considered in design of SFRC structural members. The parameters that describe the post-cracking behavior of SFRC in tension are often derived using indirect methods combined with inverse analysis techniques applied to the results obtained from three- or four-point prism bending tests or from determinate round panel tests. However, there is still some uncertainty regarding the most reliable methodology for evaluating the post-cracking behavior of SFRC. In the present study a steel fiber reinforced self-compacting concrete (SFRSCC) was developed and its post-cracking behavior was investigated through an extensive experimental program composed of small determinate round panel and prism bending tests. Based on the results obtained from this experimental program, the constitutive tensile laws of the developed SFRSCC were obtained indirectly using two numerical approaches, as well as three available analytical approaches based on standards for estimating the stress versus crack width relationship (). The predictive performance of both the numerical and analytical approaches employed for estimating the relationship of the SFRSCC was assessed. The numerical simulations have provided a good prediction of the post-cracking behavior of the concrete. All the analytical formulations also demonstrated an acceptable accuracy for design purposes. Anyhow, among all the employed approaches, the one that considers the results of small determinate round panel tests (rather than that of prism bending tests) has predicted more accurately the constitutive tensile laws of the SFRSCCFEDER funds through the Operational Programme for Competitiveness and Internationalization - COMPETE and by national funds through FCT (Portuguese Foundation for Science and Technology) within the scope of the project InOlicTower, POCI-01-0145-FEDER520 016905 (PTDC/ECM-EST/2635/2014)

A Solvable Regime of Disorder and Interactions in Ballistic Nanostructures, Part I: Consequences for Coulomb Blockade

We provide a framework for analyzing the problem of interacting electrons in a ballistic quantum dot with chaotic boundary conditions within an energy $E_T$ (the Thouless energy) of the Fermi energy. Within this window we show that the interactions can be characterized by Landau Fermi liquid parameters. When $g$, the dimensionless conductance of the dot, is large, we find that the disordered interacting problem can be solved in a saddle-point approximation which becomes exact as $g\to\infty$ (as in a large-N theory). The infinite $g$ theory shows a transition to a strong-coupling phase characterized by the same order parameter as in the Pomeranchuk transition in clean systems (a spontaneous interaction-induced Fermi surface distortion), but smeared and pinned by disorder. At finite $g$, the two phases and critical point evolve into three regimes in the $u_m-1/g$ plane -- weak- and strong-coupling regimes separated by crossover lines from a quantum-critical regime controlled by the quantum critical point. In the strong-coupling and quantum-critical regions, the quasiparticle acquires a width of the same order as the level spacing $\Delta$ within a few $\Delta$'s of the Fermi energy due to coupling to collective excitations. In the strong coupling regime if $m$ is odd, the dot will (if isolated) cross over from the orthogonal to unitary ensemble for an exponentially small external flux, or will (if strongly coupled to leads) break time-reversal symmetry spontaneously.Comment: 33 pages, 14 figures. Very minor changes. We have clarified that we are treating charge-channel instabilities in spinful systems, leaving spin-channel instabilities for future work. No substantive results are change

Long-range Angular Correlations On The Near And Away Side In P-pb Collisions At √snn=5.02 Tev

7191/Mar294

Acidentes químicos ampliados: um desafio para a saúde pública The increase in chemical accidents: a challenge for public health

Os acidentes envolvendo substâncias perigosas nas atividades de transporte, armazenamento e produção industrial de produtos químicos constituem um sério risco à saúde e ao meio ambiente. Objetiva-se discutir, no âmbito da saúde pública, alguns dos desafios que esses tipos de acidentes colocam, principalmente para os países de economia periférica. Através da combinação de informações quantitativas e qualitativas, foram definidos e caracterizados esses tipos de acidentes e seus diversos riscos. Esses acidentes têm se apresentado com a maior gravidade nos países de economia periférica, embora a maioria deles venha ocorrendo sem o adequado registro de informações básicas para a avaliação e vigilância, como é demonstrado no caso do Rio de Janeiro (Brasil). Além da tarefa de se avaliar as conseqüências de eventos, por vezes extremamente complexos, coloca-se também, a de formular estratégias de controle e prevenção em realidades sociais que configuram um terreno fértil para a ocorrência e agravamento dos mesmos.<br>Chemical accidents involving explosions, large fires and leakages of hazardous substances occuring during transport, storage and industrial production of chemicals constitute a real challeng to health, environmental and industrial safety professionals. The aim of this article is to discuss the main questions that this kind of accident provokes, in terms of public helth, particularly in developing countries such as Brazil. The paper defines and characterises these accidents and the various health risk they involve excluding the leakages of hazardous substances during "normal" production in industry - through the combination of quantitative and qualitative information drawn from the international literature on the subject. From some examples of chemical accidents such as occurred in Bophal (Índia), Vila Socó (Brazil), São Paulo (México) and data of the World Health Organization (WHO), the authors seek to show that these events present a worsening, in terms of immediate deaths and injuries, in developing countries. The statistics of chemical accidents which occurred during the last ten years (1984 to 1993) in the State of Rio de Janeiro are used taken as a frame reference for the purpose of bringing to light the great number of occurrences made with no registration of basic information regarding assessment or surveillance. The complexity of causes and consequences, together with the structural problems of developing countries, present public health professionals and institutions, with some important tasks especially those os health risk assessment and the formulation of strategies to prevent and control future major chemical accidents