Artigos de Revista

Coastal hazards such as flooding and erosion can cause large economic and human losses. Under this threat, early warning systems can be very cost-effective solutions for disaster preparation. The goal of this study was todevelop, test, and implement an operational coastal erosion early warning system supported by a particularmethod of machine learning. Thus, the system combines Bayesian Networks, and state-of-the-art numericalmodels, such as XBeach and SWAN, to predict storm erosion impacts in urbanized areas. This system wasdeveloped in two phases. In the development phase, all information required to apply the machine learningmethod was generated including the definition of hundreds of oceanic synthetic storms, modeling of the erosioncaused by these storms, and characterization of the impact levels according to a newly defined eerosion iimpactindex. This adimensional index relates the distance from the edge of the dune/beach scarp to buildings and theheight of that scarp. Finally, a Bayesian Network that acted as a surrogate of the previously generated informationwas built. After the training of the network, the conditional probability tables were created. These tablesconstituted the ground knowledge to make the predictions in the second phase. This methodology was validated(1) by comparing 6-h predictions obtained with the Bayesian Network and with process-based models, the latestconsidered as the benchmark, and (2) by assessing the predictive skills of the Bayesian Network through theunbiased iterative k-fold cross-validation procedure. Regarding the first comparison, the analysis considered theentire duration of three large storms whose return periods were 10, 16, and 25 years, and it was observed that theBayesian Network correctly predicted between 64% and 72% of the impacts during the course of the storms,depending on the area analyzed. Importantly, this method was also able to identify when the hazardous conditionsdisappeared after predicting potential consequences. Regarding the Regarding the second validationapproach, second validation approach, the k-fold cross-validation procedure was applied to the peak of a set ofvarying storms and it demonstrated that the predictive skills were maximized (63%

Application of carbon fibre reinforced polymer (CFRP) composites in strengthening of existing reinforced concrete(RC) structures has been widely accepted. However, the durability of adhesively bonded CFRP-concretejoint has not yet been fully investigated, which therefore paves the way to the topic addressed in this work:the durability of the joint in concrete elements strengthened with CFRP laminate using externally bondedreinforcement (EBR) technique. Concrete strengthened elements were kept in laboratory-controlled environments(approximately 20

Fibre-reinforced polymer (FRP) composites have gained popularity in civil structural applications due to their advantages over traditional materials. Despite their proven better performance in harsh conditions, FRP composites are susceptible to degradation due to various environmental agents; moreover, the lack of durability data for relatively thick laminates produced by pultrusion is a concern. To address this, in the scope of the Durable-FRP project, an extensive experimental program was conducted to assess the durability of thick FRP laminates produced by pultrusion, consisting of glass fibres and unsaturated polyester and vinyl ester resin matrices, subjected to accelerated laboratory ageing and in-situ natural weathering. This paper presents preliminary results from durability tests on such glass-FRP (GFRP) laminates under particular thermal ageing environments, including constant temperatures of -15 °C, 20 °C, 40 °C, and 60 °C for a period over 12 months, as well as 100 and 200 thermal cycles between 15 °C and 60 °C. Following environmental exposure, the degradation of mechanical properties was evaluated using various tests, including tension (in both longitudinal and transverse directions), compression, flexure, in-plane shear, and interlaminar shear. In general, minor mechanical degradation was observed, except in terms of transverse tensile strength (resin-dominated) following constant exposure to extreme temperatures, with minimum property retentions of 74% and 83% at -15 °C, for vinyl ester and unsaturated polyester matrices, respectively.

A first characterization of greenhouse gases had been carried out to study their role and impact in a productive transitional coastal system of the southern Portugal

This study focuses on natural convection heat transfer in building heating and ventilation. Amid advancements in natural ventilation and a changing energy landscape, innovative heating methods are crucial. Thermal radiators play a key role in enhancing heat convection and understanding thermal plumes to optimize heating efficiency.This study investigates the use of coloured smoke sources to visualize thermal plume flow fields in real-scale(in-situ), naturally ventilated large spaces, distinguishing itself from most studies that prioritize enhancingthermal efficiency radiator. It offers a way for both qualitative and quantitative validation of a CFD model usingpassive scalars and experimental images to illustrate thermal plume propagation. This novel approach provides an effective way to visualize and understand thermal plumes in spaces where other experimental techniques are challenging to implement.Experimental results showed high consistency between measured and CFD values for velocity, temperature,and heat exchange, with differences below 10 %. The study unveiled a low impact of initial smoke source ve-locities on plume visualization. Using coloured smoke images to validate the CFD model yielded errors from 2.3 % to 14.5 %, proving the method

The aim of the present study is to assess if recycled gypsum from plasterboard waste can be added to earth plastering mortars instead of raw calcium sulphate hemihydrate when a mineral binder addition is foreseen to improve durability. Earth mortars with additions of 0 %, 5 %, 10 % and 20 % vol. of raw hemihydrate, gypsum milled from plasterboards with and without thermal treatment were produced and tested. In general, the additions led to an overall improvement in mechanical strength and resistance to water and did not significantly influence the hygroscopicity of the earth plaster. In general, earth mortars with untreated gypsum waste achieved comparable to superior results compared to mortars with treated gypsum waste, indicating the viability of using recycled gypsum from plasterboard without thermal treatment as earthen plaster addition.

Volatile organic compounds (VOCs) and ozone (O3) are harmful pollutants present in indoor air. Indoor concentrations of VOCs are typically higher than outdoors, due to the presence of indoor sources like building materials and ozone-surface reactions. The study aims to identify and quantify the ozone reactivity and primary and secondary emissions of different indoor coatings. The coatings selected for the study were three gypsum-based plastering mortar, with and without the addition of a bio-waste from Acacia dealbata (raw bark, BA, and bark heated at 250 °C, BA250), two clay plasters (one with sand and the other with seashells as additional aggregate), applied both as basecoat and topcoat (on drywall), and one un-coated drywall. All the products tested had ozone deposition velocities that would reduce the indoor ozone concentration meaningfully if implemented in a real indoors, contributing to the improvement of indoor air quality. The gypsum-based plaster shows the lowest ozone deposition velocity, but also the lowest primary and secondary emissions. The addition of bark, either BA or BA250, increased by 50% the ozone deposition velocity of the coating but also increased primary and secondary emissions by 80% (BA) and 200% (BA250), with methanol (m/z 33.030) accounting for about 60% of the increase. The addition of crushed seashells to the formulation of the clay-based plasters lowered the secondary emission yields (102% and 120% respectively, when applied as base and topcoat).

Recycled cement (RCP) retrieved from old cement waste aims to replace carbon-intensive ordinaryPortland cement (OPC) in earth stabilisation, improving the mechanical performance anddurability of earth construction, without significantly compromising its ecological character andthermophysical properties. This study analyses the microstructure and hygroscopic behaviour ofcompressed earth blocks (CEB) stabilised with RC. In addition, soil was partially replaced withconstruction and demolition waste (CDW) to further improve the CEB sustainability. To this end,the sorption-desorption isothermal behaviour of CEB with different soils, types and contents ofstabiliser (0

Earth plasters have several advantages. Nevertheless, they are vulnerable when in contact with liquid water. For that reason, they have low durability when applied as an outdoor coating or in indoor areas with potential contact with water. In this study, the influence of six different surface treatments (traditional and innovative, based on raw materials and on waste) applied on a pre-mixed earth plaster, applied by a roller (r) or as a spray (s), was assessed. The treatments were: limewash (L), beeswax (BW), linseed oil (LO), graphene oxide dispersion (GO), water from paper immersion (WP) and water from gypsum plasterboard paper immersion (WPG). The application of L, BW and LO, despite the color change, improved the water resistance and the surface performance of the earth plaster (less than 80%

This study evaluated the durability of three innovative multilayer insulation systems incorporating thermal mortars with EPS aggregates and silica aerogel granules after hygrothermal accelerated aging and one year of natural aging at an urban site in Portugal. The loss of performance was assessed after the accelerated aging and every three months of natural aging using non-destructive testing. Chemical-morphological analyses were alsocarried out prior to and after accelerated and natural aging. Results obtained after accelerated and natural aging were compared, thus contributing towards a deeper understanding of possible synergistic effects of several degradation agents and mechanisms on the long-term durability of multilayer insulation systems. The Coffin-Manson equation showed that the accelerated aging procedure (~13 days of heat/rain cycles and 5 days of heat/cold cycles) adopted herein corresponds to approximately 11 years of natural aging in typical urban conditions. The results show a significant increase in capillary water absorption and drying capacity after aging.Extensive surface microcracking was observed after accelerated aging and after 3 months of natural aging, especially in the systems facing North. Traces of biological growth were detected on both the artificially and naturally aged systems, whereas aesthetic alterations were more pronounced in North-oriented specimens after 3 months of exposure, with significantly lower surface gloss and a darker tone. On the other hand, color change cannot be detected in the artificially aged systems (