Artigos de Revista

This paper describes the process of use cases prioritizing by ranking their usefulness to improve water losses, control and water-energy efficiency in networks, to provide new services to the consumer, to improve billing systems and pricing schemes, to improve leak detection and water-energy efficiency and to develop better services to consumers. Results showed that priority use cases were to obtain water consumption data, understand water consumption and assist consumers to increase water use efficiency (consumer domain) and to obtain water and related energy consumption data, understand water consumption and get support to increase operational efficiency (water utility domain).

Após alguns anos em que o transporte ferroviário teve um declínio acentuado, ultimamente temvindo a assistir-se, em vários países, à modernização de linhas férreas antigas, nomeadamente procedendo àreabilitação da via-férrea. Vários desses casos referem-se a vias que se pretende que venham a servir essen -cial mente o transporte de mercadorias. Durante a reabilitação das vias férreas existem vantagens técnicas,económicas e ambientais em manter, se possível, os materiais existentes, em particular a camada de balastroferroviário contaminado com solos finos, sob as novas camadas de reforço. Este trabalho apresenta resultadosde estudos realizados com o objetivo de reabilitar uma via-férrea para o transporte de mercadorias, localizadaem África. Para além da caracterização realizada in situ, construíram-se trechos experimentais para testardiversas soluções estruturais para reabilitação da plataforma ferroviária e realizaram-se modelações numéricasda via, contemplando essas soluções. Os resultados dos estudos permitiram concluir que é possível levar acabo o reforço estrutural da plataforma, de forma eficiente, em termos técnicos e económicos.

Fire safety is an important issue of buildings safety, especially when their fire load contents enhance the risks of fire deflagration. When existing timber structures are involved, the most usual way to improve its reaction to fire is to treat wood with fire retardants. This study focuses on the surface protection of existing timber roof structures against fire, through the use of Fire Retardant (FR) treatments applied on site. An experimental investigation was carried out to study the effect of FR treatments on timber reaction to fire, with a special emphasis on timber members with biological deterioration and previously treated with preservative products. The behaviour and effectiveness of intumescent and non-intumescent treatments was also investigated. The study showed that the application of FR treatments improved the reaction to fire of timber, even in the presence of previous preservative treatments. However, the choice of the specific FR treatment should take into account the substrate conditions. Besides, test results suggest that protection systems involving multi layers (intumescent and non-intumescent) with different functioning modes each are likely to have a good global performance on the protection of timber elements against fire.

As rochas graníticas representam em Portugal cerca de 40% do volume total de agregados para concreto. Estas rochas são normalmente consideradas como sendo de reação lenta ou até como não reativas aos álcalis. Contudo, diversos casos de reação álacalis-agregado (RAA) têm sido diagnosticados em estruturas de concreto nas quais foram utilizadas rochas graníticas. Com o objetivo de diminuir a incerteza na avaliação da reatividade potencial aos álcalis de granitos foi desenvolvido um projeto de investigação no qual os resultados deste artigo se inserem. No âmbito deste projeto foram estudadas trinta e uma amostras colhidas em diferentes regiões de Portugal, apresentando-se neste artigo os resultados de oito dessas amostras. Os ensaios realizados incluem a caraterização petrográfica dos agregados e ensaios de expansão de barra de argamassa e prisma de concreto. Conclui-se que o conteúdo em quartzo microcristalino se correlaciona melhor com os resultados do ensaio em prisma de concreto RILEM AAR-4.1 do que com os outros ensaios de expansão.

No presente trabalho, investiga-se, usando a modelação numérica, a interacção de um escoamentouniforme laminar e bidimensional com um conjunto de três cilindros. Dois cilindros de controlo sãoposicionados simetricamente na esteira de um cilindro principal, induzindo alterações significativas natopologia do escoamento e nos respectivos coeficientes aerodinâmicos. Esta forma de controlo dos esforços éconhecida na literatura por controlo passivo da esteira. Os cilindros de controlo têm um diâmetro de D/8, sendoD o diâmetro do cilindro principal. As simulações numéricas foram realizadas para um número de Reynolds200. Dos vários resultados obtidos no estudo, destaca-se que para uma distância entre os centros dos cilindrosde controlo e o centro do cilindro principal de 0.7D na direcção do escoamento e 0.7D na direcção transversalao escoamento, o coeficiente de arrasto médio do cilindro principal é reduzido de 27% comparando com o valorde um cilindro isolado, mas, considerando a estrutura total (o conjunto dos três cilindros), a redução docoeficiente de arrasto médio é de apenas de 4%. No entanto, para esta configuração, os coeficientes root-meansquarede arrasto e de sustentação são fortemente reduzidos, 0.0001 e 0.0036, respectivamente, comparando osde um cilindro isolado, 0.035 e 0.47, respectivamente, o que corresponde a uma redução da intensidade dasflutuações que actuam no cilindro principal de três ordens de grandeza.

As intervenções na cidade central e na cidade periférica têm de ser, cada vez mais, de pequena escala, bem pormenorizadas e qualificadas no seu desenho de arquitectura e muito sensíveis aos respectivos habitantes e aos próprios sítios que são habitados, que passa por uma bem fundamentada escolha tipológica de conjuntos de edifícios e espaços públicos.

A kinetic based comparison between expansion tests for alkali-aggregate reactivity was carried out deriving critical rates from test criteria, in an earlier paper. The present paper checks the assumptions and models of that earlier comparison against results with real aggregates varying in alkali reactivity. Using the same approach, for each aggregate, expansion rates for three expansion tests were estimated, corrected for alkalinity and depicted as an Arrhenius plot. The relationship used data from NF P18-590, ASTM C 1260 and ASTM C 227 expansion test-methods and shows linear Arrhenius plots for several aggregates, aligned almost parallel to the line obtained for test criteria. Aspects related to the different experimental conditions on test-methods and their effects are discussed. The proposed conclusion is that both standards and aggregate results, in the given conditions, are not inconsistent from the kinetic point of view. Some suggestions are made for improving the accuracy of the relationship obtained.

The main purpose of this study is to investigate the uncertainties in the modelling of salinity fields in the Ria de Aveiro lagoon associated with the estimation of river flow discharges. The prediction of fresh water inputs is necessary to properly implement forcing conditions and consequently to provide accurate forecasts of baroclinic circulation in coastal lagoons. Located in the north-western Portuguese coast, the Ria de Aveiro is a shallow vertically homogeneous mesotidal coastal lagoon with a complex geometry. Although it is tidally dominated, it receives freshwater from five rivers, the Vouga, Antuã, Cáster, Boco and Ribeira dos Moínhos, whose contributions are responsible for the salinity variation within the system. This research concerns the accurate prediction of river flow to be used in the operational forecast system of the lagoon. Given the lack of observed data for river discharges, as there are only two real time measuring stations located in the Vouga and Antuã river basins, but far from the lagoon, alternative estimation approaches are needed. In order to estimate the river discharges for all five rivers, two different approaches were considered: the first estimates the Vouga river flow, the major fresh water source, based on the nearest real time measuring station and estimates the other river flows based on river basin areas proportionality; the second establishes river flows based on the precipitation/river flow relationships for the Vouga and Antuã rivers and on the areas of the other river basins using the SWAT model. The methodology comprises the exploitation of the 3D unstructured-grid hydrodynamic model SELFE, required to adequately simulate the flow and transport of salt in very complex domains such as the Ria de Aveiro. The model is forced by water elevations at the ocean boundary and river flows at the river boundaries, and atmospheric drivers at the surface (wind stress, atmospheric pressure and heat fluxes). The salinity model predictions were compared with data from seven stations, and its accuracy was assessed through Root Mean Square Error (RMSE). The river flows estimated by the first method led to the best fit between observed and predicted salinity.

One of the European policy objectives, as envisaged by the EC Transport White Paper, is to reduce Europe's dependence on imported oil and to cut greenhouse gas emission (GHG) from transport by 20% by 2030 and by 70% until 2050 (with respect to 2008 levels). For achieving this goal, the role of integrated energy and urban mobility systems are explored as part of a city