The influence of chemical reaction conditions upon poly(styrene‐methyl methacrylate‐acrylic acid) synthesis: Variations in nanoparticle size, colour and deposition methods

Monodisperse latex nanospheres of poly(styrene‐methyl methacrylate‐acrylic acid) with different sizes were synthetised by soap‐free emulsion copolymerisation and applied onto polyamide 6,6 fabrics by two methods, ie, gravitational sedimentation and dip‐drawing. Different‐sized nanospheres were synthetised by varying temperature and stirring velocity as reaction parameters. Scanning electron microscopy and scanning transmission electron microscopy were used to evaluate nanosphere sizes and deposition structures. The results showed two different nanosphere structural arrangements on the fabric surface, a hexagonal packed centre structure in the even surfaces and a square arrangement in the out‐of‐plane surfaces. Different colours were observed according to particle size, namely, violet (ca. 170 nm), blue (ca. 190 nm), green (ca. 210 nm), yellow (ca. 230 nm) and red (ca. 250 nm). An iridescence effect was also observed, displaying different colours at different observation angles. By controlling the size of the nanospheres it was possible to obtain different, brilliant and iridescent colours. Using different nanosphere sizes it was possible to obtain different interplanar distances and to control the light scattering in the crystalline lattice planes, obtaining Bragg diffraction patterns.Fundação para a Ciência e a Tecnologia, Grant/Award Number: IF/00071/2015, PTDC/CTM-TEX/28295/2017 , SFRH/BD/145269/2019 and UID/CTM/00264/2019; European Regional Development funds (FEDER); Competitiveness and Internationalization Operational Program (POCI)—COMPETE, Grant/Award Number: POCI-01-0145-FEDER-0071

Patterns and controls on fluvial incision in the lower Douro River (Western Iberia) following endorheic-exorheic drainage reorganization

The Douro River, is ~900 km long and has a drainage basin of ~97,600 km2, crossing most of the Iberian Peninsula from east to west. The evolution of the Douro system documents an outstanding example of a continental-scale drainage reorganization, reflecting a transition from endorheic to exorheic conditions. By the middle Cretaceous, the passive Western Iberian Margin was tectonically reactivated by an increasing N-S to NW-SE compression, leading to intraplate deformation. This deformation peaked at ~9.5 Ma (middle Tortonian) resulting in differential uplift of crustal blocks. Until ~3.7 Ma (middle Pliocene) the regional drainage was routed east into the endorheic Douro Cenozoic Basin (DCB). The Lower Douro River Section (LDRS) is limited upstream by a pronounced knickzone called the Arribas do Douro developed into resistant basement bedrock. Along the LDRS, the Douro incises into hard granitic and metamorphic rocks crossed by active fault zones, before reaching the Atlantic coast. The main valley along the LDRS displays a fluvial staircase configuration of 11 levels, with the upper levels occurring as erosional bedrock straths and the 3 lowest levels as straths with a fluvial sediment cover. Recent work has indicated that capture-related re-organization via headwards erosion of a small Atlantic draining system was unlikely due to the high resistance of the basement bedrock and instead overspill is a more plausible explanation (Cunha et al., 2019). Although the endorheic-exorheic reorganization leading to an Atlantic system, has recently been investigated, the fluvial incisional stage of the main river and tributaries is less understood along the LDRS. In this work, the characterization the transient landscape relief of four distinct sectors along the LDRS, in terms of: valley floor widthheight ratio, degree and rates of incision, uplift rates, migration of successive erosion waves and knickpoint propagation, preservation of old plateaus of the regional planation surface, influence of lithology on the relief evolution, and the staircase arrangement along the main course considering the presence/absence of aggradational levels. The LDRS can be divided in four sectors separated by two major NNESSW strike-slip fault zones, which are represented morphologically as river gorges along the uplifted blocks between pull-apart basins (e.g., Régua and Vilariça-Pocinho). The less uplifted areas are also where the aggradational strath terraces are well expressed.The 4 sectors are: I) from the river mouth till the confluence of the main northern tributary, the Tâmega River – adjacent to a wide littoral platform with inland hills (top surface <500 m); II) from the Tâmega confluence to the Mesão Frio-Régua tectonic corridor, corresponding to the uplifted relief of the Occidental Mountain Range; III) from Régua to the Pocinho-Vilariça pull-apart basin, corresponding to the High Plateaus region of Northern Portugal; IV) from Pocinho to the river elbow that marks the DCB margin, the old erosion surface of the Iberian Meseta. Cunha, P.; Martins, A.; Gomes, A.; Stokes, M.; Cabral, J.; Lopes, F.; Pereira, D.; de Vicente, G.; Buylaert, J-P.; Murray, A.; Antón, L. 2019. Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Douro River, Western Iberia. Global and Planetary Change, 181, 102985

Efficiency of different techniques in seismic strengthening of RC beam-column joints

In the last years several techniques have been proposed and used for the seismic strengthening of reinforced concrete (RC) beam-column joints using fiber reinforced polymers (FRP). The Near Surface Mounted (NSM) technique uses FRP bars or laminates inserted into grooves opened on the concrete cover and filled with epoxy adhesive. In the Mechanically Fastened and Externally Bonded Reinforcement (MF-EBR) technique, multidirectional laminates of carbon fiber reinforced polymers (MDL-CFRP) are simultaneously bonded with epoxy adhesive and mechanically fixed with anchors to the faces of the elements to be strengthened. With the aim of comparing the seismic efficiency of NSM and MF-EBR techniques, tests with RC joints, representative of the buildings construction practice in Southern European countries until the early 1970s were carried. The experimental campaign comprises cyclic tests on seven full-scale RC joints with distinct configurations when both, NSM and MF-EBR techniques, are used. The tests are described and the main results are presented and analyzed

Seismic strengthening of beam-column joints with multi-directional CFRP laminates

Technical Report 11-DEC/E-13This work is supported by FEDER funds through the Operational Programme for Competitiveness Factors – COMPETE and National Funds through FCT – Portuguese Foundation for Science and Technology under the project PTDC/ECM/74337/2006. The authors acknowledge the materials generously supplied by Hilti Portugal - Produtos e Serviços Lda., S&P Clever Reinforcement Ibérica Lda. and SECIL

Comportamento da ligação entre laminados multi-direccionais de CFRP e o betão

Relatório técnico 11-DEC/E-15O presente trabalho foi financiado pelos programas COMPETE e FEDER, projecto PTDC/ECM/74337/ 2006 da FCT – Fundação para a Ciência e a Tecnologia. Os autores manifestam os seus agradecimentos às empresas que gentilmente forneceram os materiais, nomeadamente, à Hilti Portugal – Produtos e Serviços Lda., à S&P Clever Reinforcement Ibérica Lda. e à SECIL

Bond behavior between concrete and multi-directional CFRP laminates using the MF-EBR strengthening technique

The strengthening technique based on the application of multi-directional laminates of CFRP (MDL-CFRP) simultaneously glued and anchored to the surface of the elements to be strengthened has been recently proposed. This technique was designated Mechanically Fastened and Externally Bonded Reinforcement (MF-EBR) and combines the fasteners from the MF-FRP technique with the externally glued properties from the EBR. With the aim of assessing the potentialities of this technique for seismic retrofitting, three interior RC beam-column joints were strengthened according to the MF-EBR technique and tested. This work presents the entire test program executed, including test configuration, results and corresponding analysis.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/ECM/74337/2006.FEDER- Operational Program for Competitiveness Factors – COMPET

Laminados multi-direccionais de CFRP para aplicações em engenharia civil

Recentemente tem vindo a ser proposta uma nova técnica de reforço utilizando polímeros reforçados com fibras de carbono (CFRP) na reabilitação estrutural de estruturas de betão, que consiste na aplicação de laminados multi-direccionais de CFRP (MDL-CFRP). Estes laminados são simultaneamente colados e fixados mecanicamente através de ancoragens. Neste contexto, foi desenvolvido um MDL-CFRP e, para avaliar as suas potencialidades no reforço de estruturas de betão foram realizados ensaios de arranque directo. O presente trabalho descreve os ensaios realizados e analisa os principais resultados obtidos

Nota introdutória

Apresentação do número 25 da Revista Lusófona de Educação, pelos editore

Patterns and controls on fluvial incision in the lower Douro River (Western Iberia) following endorheic-exorheic drainage reorganization

The Douro River, is ~900 km long and has a drainage basin of ~97,600 km2, crossing most of the Iberian Peninsula from east to west. The evolution of the Douro system documents an outstanding example of a continental-scale drainage reorganization, reflecting a transition from endorheic to exorheic conditions. By the middle Cretaceous, the passive Western Iberian Margin was tectonically reactivated by an increasing N-S to NW-SE compression, leading to intraplate deformation. This deformation peaked at ~9.5 Ma (middle Tortonian) resulting in differential uplift of crustal blocks. Until ~3.7 Ma (middle Pliocene) the regional drainage was routed east into the endorheic Douro Cenozoic Basin (DCB). The Lower Douro River Section (LDRS) is limited upstream by a pronounced knickzone called the Arribas do Douro developed into resistant basement bedrock. Along the LDRS, the Douro incises into hard granitic and metamorphic rocks crossed by active fault zones, before reaching the Atlantic coast. The main valley along the LDRS displays a fluvial staircase configuration of 11 levels, with the upper levels occurring as erosional bedrock straths and the 3 lowest levels as straths with a fluvial sediment cover. Recent work has indicated that capture-related re-organization via headwards erosion of a small Atlantic draining system was unlikely due to the high resistance of the basement bedrock and instead overspill is a more plausible explanation (Cunha et al., 2019). Although the endorheic-exorheic reorganization leading to an Atlantic system, has recently been investigated, the fluvial incisional stage of the main river and tributaries is less understood along the LDRS. In this work, the characterization the transient landscape relief of four distinct sectors along the LDRS, in terms of: valley floor widthheight ratio, degree and rates of incision, uplift rates, migration of successive erosion waves and knickpoint propagation, preservation of old plateaus of the regional planation surface, influence of lithology on the relief evolution, and the staircase arrangement along the main course considering the presence/absence of aggradational levels. The LDRS can be divided in four sectors separated by two major NNESSW strike-slip fault zones, which are represented morphologically as river gorges along the uplifted blocks between pull-apart basins (e.g., Régua and Vilariça-Pocinho). The less uplifted areas are also where the aggradational strath terraces are well expressed.The 4 sectors are: I) from the river mouth till the confluence of the main northern tributary, the Tâmega River – adjacent to a wide littoral platform with inland hills (top surface <500 m); II) from the Tâmega confluence to the Mesão Frio-Régua tectonic corridor, corresponding to the uplifted relief of the Occidental Mountain Range; III) from Régua to the Pocinho-Vilariça pull-apart basin, corresponding to the High Plateaus region of Northern Portugal; IV) from Pocinho to the river elbow that marks the DCB margin, the old erosion surface of the Iberian Meseta. Cunha, P.; Martins, A.; Gomes, A.; Stokes, M.; Cabral, J.; Lopes, F.; Pereira, D.; de Vicente, G.; Buylaert, J-P.; Murray, A.; Antón, L. 2019. Mechanisms and age estimates of continental-scale endorheic to exorheic drainage transition: Douro River, Western Iberia. Global and Planetary Change, 181, 102985