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- AA 5083 aluminium alloy corrosion in estuarine environment [Poster]Publication . Marques, Maria João; Alves, Isabel Nascimento; Gonçalves, Rita; Cunha Diamantino, Teresa
- Corrosion protection of PVD and paint coatings for selective solar absorber surfacesPublication . Nunes, A.; Carvalho, Maria João; Cunha Diamantino, Teresa; Fernandes, J. C. S.The selective solar absorber surface is a fundamental part of a solar thermal collector, as it is responsible for the solar radiation absorption and for reduction of radiation heat losses. The surface’s optical properties, the solar absorption (á) and the emittance (å), have great impact on the solar thermal collector efficiency. In this work, two coatings types were studied: coatings obtained by physical vapor deposition (PVDs) and coatings obtained by projection with different paints (PCs) on aluminum substrates. The most common industrial high performing solar selective absorbers are nowadays produced by vacuum deposition methods, showing some disadvantages, such as lower durability, lower resistance to corrosion, adhesion and scratch, higher cost and complex production techniques. Currently, spectrally selective paints are a potential alternative for absorbing surfaces in low temperature applications, with attractive features such as ease of processing, durability and commercial availability with low cost. Solar absorber surfaces were submitted to accelerated ageing tests, specified in ISO 22975-3. This standard is applicable to the evaluation of the long term behavior and service life of selective solar absorbers for solar collectors working under typical domestic hot water system conditions. The studied coatings have, in the case of PVDs solar absorptions between 0.93 and 0.96 and emittance between 0.07 and 0.10, and in the case of PCs, solar absorptions between 0.91 and 0.93 and emittance between 0.40 and 0.60. In addition to evaluating long term behavior based on artificial ageing tests, it is also important to know the degradation mechanism of different coatings that are currently in the market. Electrochemical impedance spectroscopy (EIS) allows for the assessment of mechanistic information concerning the degradation processes, providing quantitative data as output, which can easily relate to the kinetic parameters of the system. EIS measures were carried out on Gamry FAS2 Femostat coupled with a PCL4 Controller. Two electrolytes were used, 0.5 M NaCl and 0.5 M Na2SO4, and the surfaces were tested at different immersion times up to 4 weeks. The following types of specimens have been tested: Aluminium with/without surface treatment, 3 selective paint coatings (one with a poly(urethane) binder and two with silicone binders) and 2 PVD coatings. Based on the behaviour of the specimens throughout the 4 weeks of immersion, it is possible to conclude that the coating showing the best protective properties corresponds to the selective paint coating with a polyurethane resin followed by the other paint coatings, whereas both the PVD coatings do not confer any protection to the substrate, having a deleterious effect as compared to the untreated aluminium reference.
- Development of lightweight Sandwich Composites with improved Reaction to Fire and UV resistance for Double Curvature Façade Panels [Poster]Publication . Rocha, Helena; Vasconcelos, Miguel; Malheiro, Joana; Nascimento, António; Paula, Delves; Simões, Nuno; Barreiros, Maria Alexandra; Cunha Diamantino, Teresa; Ferreira, Cristina; Gonçalves, Diana; Antunes, PauloABSTRACT: Buildings with double curvature façades can be aesthetically pleasing, being capable of enchanting both architects and the general public Though, manufacturing of such façades can be a challenge in both technologic and economic terms Traditional molding technologies demand a unique mold for each panel geometry resulting in substantial costs related to raw materials and storage space, and long lead times for designing and manufacturing. A reconfigurable multipoint mold has been identified to solve this issue, where an array of moving pins can have their height quickly adjusted to form the required shape and molding surface. Another present technological challenge is the highly demanding fire resistance requirements Certain European countries require that public and civil buildings comply with the highest grades of EN 13501 standard, A 2 s 1 d 0 and B, s 1 d 0. That is a serious constraint when developing lightweight sandwich fiber reinforced polymer FRP composites, as polymeric materials do not naturally present good reaction to fire behavior Furthermore, the polymeric raw materials should present suitable processability with the reconfigurable multipoint mold and supporting processing equipment and allow the manufacturing of sandwich structures Sandwich composites structures are lightweight solutions with high stiffness, consisting of two composite laminate faces, separated by a lightweight core material, commonly made of foam or honeycomb.
- Enhancing modular facade systems with natural materials: Durability and sustainability of wood-based solutions [Poster]Publication . Morgado, Vanessa; Ferreira, Cristina; Vieira, Ana; Alves, Isabel N.; Donato, Mariana; Costa, Luís; Rocha, Jorge; Barreiros, Maria Alexandra; Cunha Diamantino, Teresa
- Fire-resistant materials: characterization and thermal behavior of intumescent gels for fire resistant glass [Poster]Publication . Donato, Mariana; Esteves, M. Alexandra; Capelo, Anabela; Oliveira, Fernando; Ferreira, Cristina; Alves, Isabel N.; Morgado, Vanessa; Correia, Jose B.; Teixeira, Jennifer P.; Oliveira Fernandes, Carolina; Silva, Ricardo Magno Lopes; Rocha, Jorge; Salomé, Pedro; Cunha Diamantino, Teresa; Barreiros, Maria Alexandra
- Gold electrodeposition from ionic liquids: an alternative to conventional aqueous bathsPublication . Sá, A.I. De; Rangel, C. M.; Quaresma, S.; Eugénio, S.; Vilar, R.
- High surface area LaNiO3 electrodes for oxygen electrocatalysis in alkaline mediaPublication . Rangel, C. M.; Soares, C. O.; Silva, R. A.; Carvalho, M. D.; Jorge, M. E. Melo; Gomes, A.; Pereira, M. I. da Silva
- Intumescent Gels for Fire-Resistant Glass: Thermal Insulation, UV Protection, and Durability Studies [Poster]Publication . Esteves, M. Alexandra; Capelo, Anabela; Donato, Mariana; Oliveira, Fernando; Ferreira, Cristina; Alves, Isabel N.; Correia, Jose B.; Silva, Ricardo Magno Lopes; Hashim, Hurraira; Roy, Deepto; Passos Teixeira, Jennifer; Rocha, Jorge; Salomé, Pedro; Cunha Diamantino, Teresa; Barreiros, Maria Alexandra
- New indazole and condensed pyrazole bisphosphonatesPublication . Teixeira, Fatima; Lucas, Carla; Antunes, Inês F.; Curto, Maria João Marcelo; Duarte, M. Teresa; Andre, Vania
- New SPEEK doped membranes for ion exchange polymer electrolytes [Poster]Publication . Teixeira, Fatima; Teixeira, António P. S.; Rangel, C. M.