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    The Mediterranean climate change hotspot in the CMIP5 and CMIP6 projections

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    The enhanced warming trend and precipitation decline in the Mediterranean region make it a climate change hotspot. We compare projections of multiple Coupled Model Intercomparison Project Phase 5 (CMIP5) and Phase 6 (CMIP6) historical and future scenario simulations to quantify the impacts of the already changing climate in the region. In particular, we investigate changes in temperature and precipitation during the 21st century following scenarios RCP2.6, RCP4.5 and RCP8.5 for CMIP5 and SSP1-2.6, SSP2-4.5 and SSP5-8.5 from CMIP6, as well as for the HighResMIP high-resolution experiments. A model weighting scheme is applied to obtain constrained estimates of projected changes, which accounts for historical model performance and inter-independence in the multi-model ensembles, using an observational ensemble as reference. Results indicate a robust and significant warming over the Mediterranean region during the 21st century over all seasons, ensembles and experiments. The temperature changes vary between CMIPs, CMIP6 being the ensemble that projects a stronger warming. The Mediterranean amplified warming with respect to the global mean is mainly found during summer. The projected Mediterranean warming during the summer season can span from 1.83 to 8.49 ∘C in CMIP6 and 1.22 to 6.63 ∘C in CMIP5 considering three different scenarios and the 50 % of inter-model spread by the end of the century. Contrarily to temperature projections, precipitation changes show greater uncertainties and spatial heterogeneity. However, a robust and significant precipitation decline is projected over large parts of the region during summer by the end of the century and for the high emission scenario (−49 % to −16 % in CMIP6 and −47 % to −22 % in CMIP5). While there is less disagreement in projected precipitation than in temperature between CMIP5 and CMIP6, the latter shows larger precipitation declines in some regions. Results obtained from the model weighting scheme indicate larger warming trends in CMIP5 and a weaker warming trend in CMIP6, thereby reducing the difference between the multi-model ensemble means from 1.32 ∘C before weighting to 0.68 ∘C after weighting.The work in this paper was partly supported by the European Commission H2020 project EUCP (grant no. 776613).Peer ReviewedPostprint (published version

    Efficient one-pot preparation of thermoresponsive polyurethanes with lower critical solution temperatures

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    This work reports a simple and scalable strategy to prepare a series of thermoresponsive polyurethanes synthesized via copolymerization of dicyclohexyl diisocyanate with glycerol ethoxylate in a single one-pot system. These polyurethanes exhibit lower critical solution temperatures (LCST) at 57¿°C. The LCST of synthesized polyurethane was determined from Dynamic Scanning Calorimetry and UV-vis measurements. Both the LCST and Tg of synthesized polyurethane was tuned by varying the ratio between hard segment (dicyclohexyl diisocyanate) and soft segment (glycerol ethoxylate). Thus, Tg values could be tuned from -54.6¿°C to -19.9¿°C for samples with different flexibility. The swelling and deswelling studies were done at room temperature and above the LCST respectively. The results showed that the swelling ratio increases with the increase of soft segment (glycerol ethoxylate) in synthesized polyurethanes. Furthermore, the mechanical properties of the membrane were studied by universal tensile testing measurements. Specifically, stress at break values varied from 0.35±0.07 MPa to 0.91±0.15 MPa for the tested membranes, whereas elongation at break data ranged from 101.9±20.9¿% to 192.4±24.4¿%, and Young's modulus varied from 0.35±0.03 MPa to 1.85±0.19 MPa. Tensile strength of the films increased with the increase of the hard segment and elongation at break decreased.Peer ReviewedPostprint (published version

    An oracle for guiding large-scale model/hybrid parallel training of convolutional neural networks

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    Deep Neural Network (DNN) frameworks use distributed training to enable faster time to convergence and alleviate memory capacity limitations when training large models and/or using high dimension inputs. With the steady increase in datasets and model sizes, model/hybrid parallelism is deemed to have an important role in the future of distributed training of DNNs. We analyze the compute, communication, and memory requirements of Convolutional Neural Networks (CNNs) to understand the trade-offs between different parallelism approaches on performance and scalability. We leverage our model-driven analysis to be the basis for an oracle utility which can help in detecting the limitations and bottlenecks of different parallelism approaches at scale. We evaluate the oracle on six parallelization strategies, with four CNN models and multiple datasets (2D and 3D), on up to 1024 GPUs. The results demonstrate that the oracle has an average accuracy of about 86.74% when compared to empirical results, and as high as 97.57% for.Peer ReviewedPostprint (published version

    Panell d'estiu. Noves habitabilitats i serveis mòbils

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    Comissaris de l'Exposició: Berta Bardí Milà (Departament de Projectes Arquitectònics ETSAB | UPC) i Joan Moreno Sanz (Departament d'Urbanisme i Ordenació del Territori ETSAB, ETSAV | UPC). El 25% dels municipis de Catalunya està en risc de despoblament (2018), és a dir, la seva densitat de població és inferior als 12,5 habitants/km2 d’acord amb els indicadors establerts per la Unió Europea. Aquest desequilibri demogràfic afecta de manera especial les comarques centrals i de muntanya, i la franja de població jove amb una edat inferior als 3 5 anys. Les causes del despoblament juvenil en el medi rural són múltiples i tenen a veure amb la precarietat laboral, la manca d’oferta residencial assequible i el dèficit d’inversió en infraestructures. En aquest sentit, s'han agrupat un seguit d'iniciatives acadèmiques per tal de revertir la situació. Per una banda, els treballs d'intervenció sobre el patrimoni de les colònies industrials del Llobregat de Projectes V-tarda de l'ETSAB UPC, per l'altra el Taller d’estiu UPV-UPC sobre desenvolupament rural i noves habitabilitats, i l’edició d’enguany del Taller de Territori del Màster en Projectació Urbanística (UPC School

    Viability of PEEK for high-temperature microvascular composites manufacture

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    Microvascular composites are materials with an inner hollow network which allows the circulation of fluids. This functionalizes the composite materials, giving them further applications such as self-healing or active cooling. Some of the already existing microvascular composites are made with fiber reinforced epoxy resin with cavities created by removal of a sacrificial low temperature resistant polymer insert. Current research is focused on the obtention of microvascular composites that can withstand higher service temperatures than epoxy, using polyimide as the high-temperature resin matrix. The aim of this project is to find a suitable sacrificial material that will withstand the higher curing temperatures of the polyimide while allowing its easy removal from the matrix. Three different candidate sacrificial materials were studied for this purpose: PEEK, PPS, and PC. Preliminary DSC test showed that the melting temperature of the PEEK was close to the range of the chosen resin. PPS melting temperature and PC glass transition temperature were below this range of curing temperatures. TGA test revealed that the degradation suffered by the different materials at the curing temperature of the polyimide was considerably low. A small-scale test mimicking the actual microvascular composite manufacturing conditions was designed to study the actual behavior of the different materials when heated. It was seen that both the PEEK and the PPS could not flow without applying extra pressure for the desired range of temperatures. Furthermore, a scaled model test revealed that there was no visible interaction between the different materials tested and the polyimide resin. The initial study showed that PEEK and PPS are not readily viable to use due to the apparent difficulties to remove them from the composite by just applying heat. PC was also considered not viable for this application since it softened too much a too low temperature.Outgoin

    Interludi

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    Comissaris de l'Exposició: Berta Bardí Milà (Departament de Projectes Arquitectònics ETSAB | UPC) i Joan Moreno Sanz (Departament d'Urbanisme i Ordenació del Territori ETSAB, ETSAV | UPC). El 25% dels municipis de Catalunya està en risc de despoblament (2018), és a dir, la seva densitat de població és inferior als 12,5 habitants/km2 d’acord amb els indicadors establerts per la Unió Europea. Aquest desequilibri demogràfic afecta de manera especial les comarques centrals i de muntanya, i la franja de població jove amb una edat inferior als 3 5 anys. Les causes del despoblament juvenil en el medi rural són múltiples i tenen a veure amb la precarietat laboral, la manca d’oferta residencial assequible i el dèficit d’inversió en infraestructures. En aquest sentit, s'han agrupat un seguit d'iniciatives acadèmiques per tal de revertir la situació. Per una banda, els treballs d'intervenció sobre el patrimoni de les colònies industrials del Llobregat de Projectes V-tarda de l'ETSAB UPC, per l'altra el Taller d’estiu UPV-UPC sobre desenvolupament rural i noves habitabilitats, i l’edició d’enguany del Taller de Territori del Màster en Projectació Urbanística (UPC Schoo
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