Artigos de Revista

N/A

Generation of virtual poles, based on the statistical distribution of selected visual and physical properties, and the estimation of their mechanical properties are of great help for predicting the quality of the roundwood that a forest stand can provide. With this objective in mind, an algorithm, SIMPOlE (SIMulator of POLEs), was developed. This algorithm allows the generation of pole's geometry, as well as the mechanical properties of clear wood and the distribution of knots along its length. This generation is made through statistical distributions. The generated poles are simulated, either according to standard EN14251 or according to EN14229, for testing with simple supported beam conditions or with cantilever beam conditions, respectively. The algorithm outputs are: the bending strength, the modulus of elasticity, the location, and cause of failure. The algorithm was calibrated with a sample of 56 maritime pine utility poles and validated with another sample of 57 small diameter maritime pine poles. The results for the validation sample show: for bending strength, a mean error of 16.9%, and for modulus of elasticity, a mean error of 17.2%. Based on these results, the algorithm shows potential to estimate mechanical characteristics of small diameter poles from a forest.

Neste trabalho é analisado um dispositivo de extração de energia das ondas do tipo coluna de água oscilante sob a ação de ondas regulares de diferentes períodos. São realizadas variações no comprimento submerso da parede frontal e no comprimento da câmara. Para tal é utilizado o código numérico FLUINCO, o qual é baseado nas equações RANS e a discretização é realizada utilizando o método semi-implícito de Taylor-Galerkin de dois passos. Uma formulação lagrangeana-euleriana arbitrária (ALE) é utilizada para permitir a solução de problemas que envolvem movimentos da superfície livre. Alguns resultados são comparados com os obtidos utilizando o programa FLUENT. São apresentados a amplificação (relação entre a altura da onda incidente a e dentro da câmara), distribuição das velocidades e vetores de velocidade.

N/A

A construção de uma Arquitectura Urbana e do Habitar estimulante, porque harmonizada com as boas medidas do homem e bem reflectidas nas boas medidas da cidade e das vizinhanças que a compõem, nunca será possível em espaços urbanos monótonos e descaracterizados. Não devemos pensar na cidade habitada como um sítio de diversidade obrigatória ou “pictórica”, mas temos de a pensar em termos de sequências de sítios com alguma singularidade e, mesmo, pontualmente, com expressiva singularidade.

There is an increasing trend to apply GNSS continuous observation of short baselines to the monitoring of engineering works, such as bridges and dams, for their structural analysis and safety control. In the case of large dams, one important application of the GNSS continuous observation is the establishment of early warning systems that demand accurate, frequently updated information and where the analysis of the baseline time series, in order to separate signal from noise is mandatory. The paper presents a study on the performance of linear filters of the asymmetric moving average (AMA) type to smooth baseline time series. The transfer function of the AMA is adopted as a smoothing criterion to define an adequate order for the AMA, in face of the spectral density function of the baseline time series. One series of measurements of a short test baseline (325 m), materialized in the campus of the National Laboratory for Civil Engineering, is used as an example of the proposed strategy.

Para além do “jogo de entradas” e do próprio “jogo urbano”, para além da crucial integração de elementos naturais e dos papéis relacionais e de apropriação de tais elementos, para além do que se consegue atingir em termos de capacidade de vivência e de atractividade do exterior público, há, antes de tudo e talvez no fim de tudo, sempre um pouco, daquilo que dá coesão a tudo isso e que podemos definir como “o jogo das relações” em Arquitectura residencial e urbana

The work focuses on the connections of strain localization modeling of material failure and discrete fracture mechanics. It is an attempt to give an answer to the old question of whether the finite element solutions of material failure problems based on strain localization techniques, using standard continuum stress–strain constitutive models equipped with strain softening, have physical sense as solutions of de-cohesive fracture mechanics problems. Based on some well-established links of the Continuum Strong Discontinuity Approach (CSDA) to material failure and cohesive fracture mechanics, some objective indicators are proposed to assess the quality of strain localization results. These indicators are simply derived on the basis of the inelastic strain distribution provided by the strain localization solutions and the direction of propagation of the localization band. They can be computed without knowledge of the exact fracture mechanics solution of the problem, and used as error indicators in a large variety of material failure situations. The proposed indicators are assessed, by means of their application to evaluation of a number of strain localization solutions of benchmark problems. Issues as the influence of the mesh structure and alignment, type of constitutive model and considered finite element techniques are examined. On the light of the obtained results, classical flaws in strain localization solutions, as mesh bias dependence and stress-locking are reinterpreted.

This paper summarizes the result of a study which contributes to the improvement of road safety in urban areas, through the creation of tools that can be used in intervention methods in the planning and management of road networks. The first tool relates the creation of a geocoded database of road accident occurred in Lisbon between 2004 and 2007, which allowed the definition of digital maps, with the possibility of a wide range of consultations and crossing of information. The second tool concerns the development of models to estimate the frequency of accidents on urban networks, according to different desegregations: road element (intersections and segments); type of accident; and inclusion of explanatory variables related to the road environment.

The PRODOMEA 8-phase model is a DSS that aims at tackling with the diversity of conditions, materials, methods and disciplines involved in monument conservation interventions by accompanying planners through conceiving, designing and execution phases, suggesting recommended actions and key actors for each phase. For most recommended actions, different options available should be considered in light of their physical-chemical, operational, socio-cultural and environmental compatibility towards the monument, which may be assessed via quantitative and semi-quantitative indicators, resulting in an overall (in)compatibility index, thus guiding decision making. The Monastery of Santa Clara-a-Velha (Coimbra, Portugal) today essentially corresponds to the early XIV century church and cloister, and to a rich collection of archaeological finds, that detail the nunnery life until it was abandoned to recurrent river flooding, in the late XVII century; ultimately, all but the church top was submersed for most of the XX century. The Monastery recently suffered an extensive conservation intervention, integrated in a larger requalification project that included the construction of a containment barrier against flooding, the exhaustive archaeological survey of the site and the construction of an interpretative centre. The PRODOMEA approach was applied as a post-intervention exercise with a double objective: to validate the use of this methodology as an assessment tool, and as an instrument to extract knowledge on best practices and on actions to be avoided or modified in future interventions. This paper reports the main outcome of this exercise. The exercise indicated that this DSS is suited to serve as a planning tool for complex interventions and, for Santa Clara-a-Velha, its using would have made a qualitative difference, namely by anticipating some of the problems that arose during execution. Attention is drawn to three illustrative examples: the apse rooftop and the cloister paving bricks and lithic remains to be remounted.