Reliability assessment of the post-limit stiffness and ductility of steel joints

Steel joints must exhibit sufficient ductility for safe structural behaviour. This is especially true for partial-strength steel joints, whereby the nonlinear response of the joint plays an important part in the overall response of the structure. Uncertainty in joint response, particularly beyond the elastic limit of the moment-rotation curve, naturally leads to a probabilistic treatment of the ductility of steel joints. It is the objective of the present paper to compare a direct probabilistic approach with simulation techniques using the Monte-Carlo method both at the component and joint level, in the context of the component method, with the aim of establishing safe limits for the ductile behaviour of the steel joints.http://www.sciencedirect.com/science/article/B6V3T-49Y3H88-1/1/4f6f0c5bb20315bc0dcbec70a68bba8

Experimental study of single span railway bridges

The main purpose of this paper is to present some results concerning the investigation that has been done by the authors regarding the dynamic response of small to médium span railway bridges using response acceleration data colleted during the measurements carried out on single span bridges on the railway track Linz-Wels, in Austria. Using output-only methods in this experimental program, it was possible to have an estimation of the igenfrequencies, mode shapes and the corresponding viscous damping. Due to the fact that the bridges were of the same type some generalizations concerning their structural behavior was possible and finite element models were calibrated in order to compute responses for real traffic. The numerical model of the bridges takes into account the track and the real boundary conditions of the decks. The measured and the computed acceleration responses of the track/bridge system are compared using two methods: the moving forces method and the interaction vehicle/track/bridge method

Influência das irregularidades da via na resposta dinâmica de pontes ferroviárias de médio vão

As irregularidades na via-férrea influenciam o comportamento dinâmico das pontes ferroviárias e aumentam os efeitos dinâmicos produzidos pela passagem dos eixos do comboio. Neste estudo é analisada a influência das irregularidades da via-férrea na resposta dinâmica de uma ponte, cuja primeira frequência natural de vibração se encontra sobre os limites definidos no Eurocódigo 1. São consideradas diferentes irregularidades, isolada a meio-vão e contínua de amplitude aleatória existente em toda a extensão do carril. As respostas máximas da ponte com as irregularidades são determinadas em termos de deslocamentos e acelerações, e comparadas com as obtidas sem as irregularidades. Recorre-se ao modelo dinâmico de via-férrea balastrada ERRI. São analisadas as acelerações na massa vibrante do balastro via-férrea bem como as forças de contacto entre a roda e o carril

Thermal performance of lightweight steel framed wall: the importance of flanking thermal losses

"First Published August 21, 2013"The thermal performance of a modular lightweight steel framed wall was measured and calculated with three-dimensional finite element method model. The focus of this article is on the effect of flanking thermal losses. The calculated heat flux values varied from ?22% (external surface) to +50% (internal surface) when flanking loss was set to 0 as a reference case, thermal transmittance equal to 0.30 W/(m2·K). Other critical parameters were the existence of fixing ?L?-shaped steel elements and the perimeter thermal insulation (10 cm XPS).The authors would like to thank the European Union for funding in the form of the QREN SI I&DT N. 5527 – ‘CoolHaven – Development of residential modular and eco-sustainable houses, with structural light steel frames’ grant.info:eu-repo/semantics/publishedVersio

Assessment of building operational energy at early stages of design – a monthly quasi-steady-state approach

In this paper a new numerical tool to estimate the operational energy of buildings, in early design stages, is presented. This tool is part of a novel approach for life-cycle analysis based on macro-components developed in the European research project SB_Steel – Sustainable Buildings in Steel. Two early design stages are considered in the scope of the methodology: the concept stage and the preliminary stage. This numerical tool enables to estimate the energy use for space heating, space cooling and domestic hot water production, taking into account (i) the climate; (ii) the use type of the building (e.g. residential, offices and commercial/industrial); (iii) the building envelope characteristics; and (iv) the building services. The developed algorithm is based on a monthly quasi-steady-state approach, modified for improved accuracy through the calibration of correction factors that depend on the climatic region and the type of building. Good results were achieved, with errors lower than 10% when compared to performance-based approaches such as the use of advanced dynamic methods. Finally, the case study of a low-rise residential building is presented, in which the results obtained from the simplified methodology are compared with the results from the simulation program EnergyPlus, showing a good agreement between them

Utilização da Espectroscopia de Ressonância Paramagnética Eletrônica para Avaliar a Presença de Impurezas em Adubos Orgânicos.

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Vibration measurements on small to medium single-span railway bridges

Due to the need for increasing train speeds several existing small to medium span bridges in the track Linz-Wels (Austria) were re-evaluated. In a preliminary numerical calculation, considering conservative values for the dynamic parameters, very high vertical accelerations were computed for some of those structures. An experimental program was thus carried out in order to get a better estimation for the dynamic behaviour of the bridges, concerning mainly the first vertical eigenfrequency and the corresponding viscous damping. The paper reports on the results of this experimental investigation and identifies some areas where further research is necessary

Árvore decisória para o controle da mastite bovina em fazenda leiteira no Pantanal.

A mastite é um processo inflamatório da glândula mamária acompanhado da redução de secreção de leite. Bactérias são, como o Staphylococcus aureus, consideradas patógeno primário e tem sido o agente isolado mais freqüentemente tanto de infecções clínicas como subclínicas. O sistema APPCC é uma abordagem sistemática para controlar potenciais perigos na produção de alimentos. É um instrumento útil para avaliar perigos e estabelecer mecanismos de controle, sempre privilegiando a prevenção. O presente estudo teve como objetivo elaborar uma arvore decisória para auxiliar na tomada de decisão no controle de mastite usando princípios da análise de perigos em pontos críticos de controle em uma fazenda leiteira, do Pantanal.bitstream/item/37490/1/CT46.pd

Enraizamento in vitro de Inhame da Costa (Dioscorea rotundata).

Com o objetivo de otimizar o meio de cultura para promover o enraizamento de plantas de inhame in vitro, microestacas de plantas de Inhame da Costa (Dioscorea rotundata) pré-estabelecidas in vitro foram utilizadas como fonte de explantes iniciais e cultivadas em meios de cultura com diferentes concentrações de sais e vitaminas do MS e doses de carvão ativado. Aos 30 dias, avaliaram-se as seguintes variáveis: altura de planta, número de folhas e de raízes. A utilização do meio ½ MS com 1,0 g de carvão ativado promoveu um melhor desenvolvimento (maior altura e maior número de folhas) das plantas de inhame. Quando se comparou os diferentes tipos de meio, o meio ½ MS também foi o mais adequado para promover o enraizamento das plantas de inhame in vitro utilizando 0,5 ou 1g L-1 de carvão ativado