Artigos de Revista

Ventilation represents a significant part of heat loss in winter, leading to the need to minimize airflow. However, it is absolutely necessary to ensure indoor air quality and the safety of the users and to control the risk of condensation. Ventilation is responsible on average for 30%e40% of energy consumption in air conditioning in Western European buildings. There is great variability in air change rates (ACH [h 1]) from country to country and the minimum value takes into account comfort, sensory and hygrothermal criteria. In Portugal improvements have been made in the air permeability of window frames, but despite the improvements also made in installing mechanical extraction ventilation devices in kitchens and toilets, these often do not guarantee the minimum number of air change rates required. Air permeability tests were recently carried out in five flats with identical construction characteristics, in the same building, with the aim of characterizing the air permeability of buildings and components, in Portugal. These data are particularly useful for improving the design of building components (e.g., windows and roller shutter boxes) and to perform simulations with reliable data.

The research reported in this paper is based on a hypothetical revealed preference experiment for valuing traffic noise nuisance as perceived in the interior of apartments located in Lisbon. The experiment used both the observed behavior of householders’ apartment choices which are designated as the ex ante situation (i.e. before living in the apartment) and a hypothetical choice of apartments located in the same block/lot of the respondent but on a different façade or floor and thus varying in terms of noise exposure. This hypothetical choice occurs after respondents have experienced traffic related noise indoors. Thus addressing a criticism of hedonic pricing models that purchasers do not always have a good understanding of the noise levels they will experience. Results from random parameters logit models indicate the importance of respondents’ experience when valuing qualitative attributes such as traffic nuisance. Whereas in the ex ante situation quiet had been mentioned only by a small percentage of the respondents as the most important location factor, in the ex post situation the quiet coefficient was found to be a statistically significant one. Additionally, the marginal value of quiet for a household located at the quieter façade was around twice as high as for a household in an apartment fronting the main road.

Neste trabalho, analisa-se o desempenho do modelo numérico SWAN (Booij et al., 1999) na caracterização da agitação marítima na zona costeira da praia da Amoreira, em Aljezur, Algarve. Para este efeito, efectua-se uma análise comparativa entre as medições de agitação marítima realizadas na Praia da Amoreira e as estimativas produzidas por esse modelo. Assim, partindo dos resultados do modelo regional de previsão da agitação marítima, WAVEWATCH III, Tolman (1999, 2002), para os dias em que foram realizadas as medições in-situ, efectuaram-se cálculos com o modelo SWAN, obtendo-se nos locais de medição valores de altura significativa, período de pico e período médio. A comparação das simulações numéricas com os dados medidos permitiu avaliar o desempenho do modelo numérico e reforçar a confiança que já existia neste modelo na sua utilização em estudos de morfodinâmica e dinâmica costeira.

Os revestimentos de piso de madeira consti¬tuem hoje em dia a solução mais comum em edifícios de habitação. A oferta do mercado é extensa, incluindo pavimentos flutuantes, par¬quetes colados e soalhos, numa ampla gama de materiais, dimensões, formas de aplicação e acabamentos. Os empreiteiros desejam revestimentos de piso tolerantes relativamente às condições de aplicação, aos imprevistos das obras e aos prazos apertados com que se defrontam. Os clientes esperam pavimentos duráveis, es¬teticamente perfeitos e de fácil manutenção. No entanto, os resultados nem sempre correspondem ao esperado e os problemas sucedem-se. Pela sua grande visibilidade, as anomalias verificadas em revestimentos de piso de madeira transformam-se muitas vezes em prejuízos significativos, grandes transtornos na entrega das obras e situações de conflito de difícil resolução. Embora haja Situações complicadas, como por exemplo nos pisos térreos ou enterrados de edifícios antigos com níveis de humidade ele¬vados, em que o emprego da madeira implica a adoção de medidas de fundo nem sempre fáceis de implementar, na maioria dos casos as anomalias verificadas em pavimentos têm origem numa associação de erros básicos que poderiam facilmente ter sido evitados.

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The employment of non traditional materials, such as soil-rock mixtures, in the construction of earthworks, for economical and environmental reasons, poses some new challenges to compaction techniques and their control. Usually, this kind of material results from the bulky rock extraction without explosives, and it can include some large size particles (greater than 0.5 m). Construction control of embankments built with soil-rock mixtures is still a subject that needs investigation, considering that it is necessary to extrapolate current test results, which have been reached by means of the truncation of the grain-size distribution curve, to the actual construction conditions. The behaviour of these materials depends of the relative fractions of theirs constituents, becoming closer to a soil, if the fine fraction is large with the coarser material scattered in it, or closer to a rockfill if the coarser particles are in contact with each other with the fines occupying the spaces between them. One of the control methods widely used in Portugal for embankments is the Hilf’s method, developed for fine soils, since it does not need a previous knowledge of the materials’ characteristics. So, taking into account the materials used in the Odelouca Dam’s shells (weathered schist with a significant fraction of large size particles), constructed in the South of Portugal, this paper presents the results from a laboratory study related to the conditions of application and the applicability of Hilf’s method to coarser soils and soil-rock mixtures. A series of laboratory tests were performed in a large-scale compactor (Toni-tecnik, with a mould diameter of 300 mm). The obtained results of the upstream shell during the construction of Odelouca Dam are presented, seeking his comparison with the Hilf’s method, which avoids the truncation of the material grain-size distribution curve and the subsequent correction of the results. Some conclusions are drawn about the applicability of this method.

Este artigo baseia-se num estudo sobre a avaliação das principais dificuldades das pessoas com limitações motoras, visuais e auditivas durante uma evacuação. Como resultado desta investigação são apresentadas algumas oportunidades de melhoria no que diz respeito à evacuação em caso de emergência de pessoas com limitações visuais, auditivas e motoras. As sugestões encontram-se divididas em cinco categorias diferentes,sendo o seu principal intuito a optimização de tempo e recursos na evacuação de edifícios.

Although the application of complex integrated models to wastewater systems is useful, it is often difficult to implement and not always suitable for the design of new systems or for their rehabilitation. Integrated simple approaches that allow assessing the environmental performance of urban wastewater systems may be advantageous, especially during the initial phases of the system planning process. This paper presents an original, straightforward approach that can be used for planning, design and operation of urban wastewater systems. The INtegrated Simplified Approach (INSA) combines the concepts of performance indicators with mass balances and can be applied to wastewater systems as a management support tool, particularly in situations where there is lack of data, economic limitations or time constraints. The INSA was applied to the Algés-Alcântara wastewater system to evaluate its environmental performance and to simulate the individual or combined impact of the rehabilitation measures proposed, thus defining their priority. The results clearly indicate that, despite the investment already made upgrading the wastewater treatment plant (WWTP), the proposed interventions must be implemented to ensure an acceptable environmental performance of the system. In addition, the results demonstrate the significant pollution loads present in stormwater, frequently higher than the pollution loads discharged into receiving waters during dry weather.

The generation of unstructured triangular grids for coastal applications requires extensive manual tunning, in order to improve the stability, accuracy and efficiency of the model simulations. As current grids reach 105-106 nodes, this manual tunning is no longer feasible. This paper presents a new post-processor that aims at optimizing the local distribution of nodes and elements by adding and deleting nodes and by changing the connections between nodes. The algorithms target a smooth transition between elements sizes by making the number of connections of each internal node as close to 6 as possible. An application of the post-processor to various grids shows that the grid roughness is reduced by 10-30%, while decreasing marginally the number of nodes and maintaining the global nodal distribution. To illustrate the benefits of the post-processor, a grid with 130.000 nodes of the maritime zone under Portuguese jurisdiction is used to simulate tides with a good accuracy (root mean square errors below 10 cm) and without numerical oscillations. The model results provide an extensive database of tidal elevations that can feed boundary conditions to local estuarine models.

Avaliação do risco de incêndio em centros urbanos antigos parte I – Aplicação do método de ARICA ao centro histórico do Funchal - A diferente concepção e materiais usados nas construções antigas fazem com que estas apresentem um risco de incêndio agravado. Tendo como objectivo avaliar o risco de incêndio do centro histórico do Funchal aplicaramse os métodos de Gretener e ARICA a alguns edifícios característicos. A aplicação dos métodos permitiu não só verifi car o risco de incêndio como detectar as diferenças entre os métodos.