174 research outputs found

    Effects of Merging Digital Elevation Models on Flood Modelling Results

    Get PDF
    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

    Frontiers in occupational health and safety management

    Get PDF
    This Special Issue of the International Journal of Environmental Research and Public Health is devoted to the “Frontiers in Occupational Health and Safety Management” [...

    Microwave Synthesis of Silver Sulfide and Silver Nanoparticles: Light and Time Influence

    Get PDF
    UIDB/50025/2020 UIDP/50025/2020 UID/CTM/50025/2019 .Silver sulfide (Ag2S) is a low band gap material, which absorbs near-infrared light and is of great importance in areas such as nanotechnology and biomedicine. We report the influence of the starting reagents, synthesis time, and light radiation on the geometry and size of silver sulfide nanoparticles and on the fraction of metallic Ag obtained in a microwave reactor. The X-ray diffraction diffractograms confirmed that Ag2S is the main product if the reaction's precursor contains silver in the oxidation state of +1 and mostly metallic silver (Ag°) when it is +2. Small nanoparticles (∼6 nm) of spherical geometry are present in the transmission electron microscopy images for the synthesis performed with the lamp light ON, while with the light switched OFF, wider and hundreds of nanometers longer particles are observed. This discriminative effect occurs with shorter synthesis time duration (<10 min) but when the time of reaction is extended, the particles coalesce for both light and dark conditions. Overall, it was observed by photoluminescence that crystalline Ag and Ag2S 4-8 nm nanoparticles obtained in 15 min and light irradiation during synthesis have a clear relative increase of the radiative recombination channels of the charged carriers, which are typical of materials characterized by the involvement of low density of states inside the band gap.publishersversionpublishe

    Effects of inter-annual freshwater inflow shifts on the community structure of estuarine decapods

    Get PDF
    The objective of this study was to evaluate how inter-annual changes in freshwater inputs have affected the decapod assemblages in the Guadiana estuary. Three major areas in the estuary were sampled during the summer, in 2001 (high inflow year and before the filling of the Alqueva dam), in 2002 (low inflow and after filling of the Alqueva dam), and in 2008 and 2009 (low inflow and after consolidation of the impacts of the Alqueva dam). A significant increase in total decapod densities was recorded for the entire estuary, but especially in the upper estuary, after the closure of the dam in 2002. Changes in salinity, turbidity and temperature, which were mainly due to changes in freshwater input and climatic influence (North Atlantic Oscillation index), had an important influence on the structure of the decapod crustacean assemblages. The major conclusions of the study were that, following the construction of the Alqueva dam and regularization of the freshwater inflow, the decapod crustacean community in the Guadiana estuary changed and a shift of the dominant decapod species to upper zones of the estuary happened. These changes, and the presence of the non-native Palaemon macrodactylus in 2008 and 2009, further enhance the importance of estuarine monitoring studies to improve ecologists’ knowledge on distinguishing and understanding natural changes and anthropogenic impacts in the ecosystem.Effets des variations interannuelles d’apports d’eau douce sur la structure d’une communauté estuarienne de décapodes. L’objectif de cette étude était d’évaluer comment les variations interannuelles d’apports d’eau douce affectent l’assemblage de décapodes dans l’estuaire du Guadiana. Trois grands domaines de l’estuaire ont été échantillonnés en été : en 2001 (année d’apports importants et avant le remplissage du barrage d’Alqueva), en 2002 (faible apport d’eau douce et après le remplissage du barrage d’Alqueva), en 2008 et 2009 (après la consolidation de l’impact du barrage d’Alqueva). Une augmentation significative de la densité totale des décapodes pour tout l’estuaire a été enregistrée, mais surtout dans l’estuaire supérieur, après la fermeture du barrage en 2002. Les variations de salinité, turbidité et température, principalement dues à des changements d’apports d’eau douce et à l’influence du climat (indice d’oscillation nordatlantique), ont eu une influence importante sur la structure des assemblages de crustacés décapodes. Les principales conclusions de l’étude sont que, à la suite de la construction du barrage d’Alqueva et de la régulation de l’apport d’eau douce, la communauté de crustacés décapodes dans l’estuaire du Guadiana a changé et les principales espèces de décapodes se sont déplacées vers les zones supérieures de l’estuaire. Ces changements, ainsi que la présence de l’espèce non native Palaemon macrodactylus en 2008 et 2009, soulignent l’importance de surveiller l’estuaire dans le futur proche afin de pouvoir mieux distinguer et comprendre les changements naturels et les impacts anthropiques sur l’écosystème

    Strategic environmental assessment in Tróia (Portugal)

    Get PDF
    Proceedings of the First International Conference on Coastal Conservation and Management in the Atlantic and Mediterranean, p. 91-98Over the last two decades, the Tróia peninsula (SW coast of Portugal) has been designated by the Portuguese authorities both as a protected area and as an area of tourism development. The private investor that took over the tourism developments in Tróia asked the Institute of Marine Research (IMAR) to undertake an SEA, to help frame the design and management of the future resort. SEA results were changed by local/central government decisions, granting “more” than stakeholder/owner’s proposal, in terms of loads and densities. This process, as well as the main characteristics and results of the SEA, are presented and discussed

    Exploring the Effect of Hierarchical Porosity in BEA Zeolite in Friedel-Crafts Acylation of Furan and Benzofuran

    Get PDF
    Hierarchical BEA zeolite was prepared through desilication or desilication followed by acid treatment. The catalytic performance of BEA zeolite samples was evaluated using Friedel-Crafts acylations with two substrates of different molecular sizes, furan (5.7 Å) and benzofuran (6.9 Å), in the presence of acetic anhydride as acylating agent. The application of the simplified Langmuir-Hinshelwood kinetic model showed that the size of the substrate leads to different catalytic activities, with improved rate constant and turnover frequency (TOF) solely in the presence of benzofuran for both desilicated and further acid treated samples. The mesopores developed during the zeolite treatments have an important role as transportation channels by reducing diffusion limitations. The application of Quantitative Structure–Property Relationships (QSPR) allowed the finding of the most relevant properties of the zeolite and substrate with impact on the catalytic parameters.publishe

    Benzo[a]phenoxazinium chlorides functionalized with chloride atoms and/or ester groups

    Get PDF
    Proceedings of the 19th Int. Electron. Conf. Synth. Org. Chem.With the aim of contributing to the development of fluorescent near-infrared (NIR) probes with applications in biomedicine, our research group is committed to the development of new water-soluble benzo[a]phenoxazine derivatives and the evaluation of their photophysical and biological potential. Herein we report the photophysical behaviour in anhydrous ethanol of four synthesised benzo[a]phenoxazinium chlorides, possessing the (3-chloropropyl)amino and/or (4-ethoxy-4- oxobutyl)amino groups at 5- and 9-positions of the polycyclic system.Thanks are due to the Fundação para a Ciência e Tecnologia (FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centres CFUM [PEst-C/FIS/UI0607/2011 (F-COMP-01-0124-FEDER-022711)] and CQ/UM [PEstC/QUI/UI0686/2013(FCOMP-01-0124-FEDER-022716)]. A post-doctoral grant to B. R. Raju (SFRH/BPD/62881/2009) is also acknowledged to FCT, POPH-QREN, FSE.info:eu-repo/semantics/publishedVersio

    Neuromuscular assessment of a stand-up paddle stroke

    Get PDF
    his study analyzed muscle activity during the stand-up paddle stroke, considering the paddling side and the adjacent and opposing muscles relative to the position of the arms during paddling. Methods: Fourteen male paddleboarders performed three trials covering 195 m in which surface electromyography of the upper trapezius, biceps brachii, triceps brachii, tibialis anterior, and gastrocnemius medialis were recorded (four-cycle strokes on each side). The data were processed according to percentage of maximum voluntary contraction (% MVC). The MVC activation values (µV) for each muscle were then calculated and presented as percentage MVC (% MVC). Results: The recovery phase accounted for 60% of the paddle cycle, while the pull phase represented 39%. During right-side paddling, higher % MVC was found in the opposite-side upper trapezius (24.35%, p < 0.01) during the pulling phase and in the adjacent biceps brachii (8.36%, p < 0.03) during the recovery phase. In left-side paddling, greater % MVC was found in the opposite-side upper trapezius (27.60%, p < 0.01) during the pulling phase and in the opposite-side triceps brachii (42.25%, p < 0.04) during the recovery phase. Furthermore, the pulling phase exhibited higher MVC in the opposite-side upper trapezius compared to the recovery phase, both in the right-side (24.35%, p < 0.03) and left-side (27.60%, p < 0.01) paddling. Conclusions: these findings help establish the muscular activity of both sides of the paddling technique and the differences between the upper and lower limbs.info:eu-repo/semantics/publishedVersio

    Synthesis and photophysical studies of new benzo[a]phenoxazinium chlorides as potential antifungal agents

    Get PDF
    A set of four new benzo[a]phenoxazinium chlorides possessing ethyl, propyl, decyl and tetradecyl groups at the 9-amino function of the heterocycle along with a propyl group at the 5-amino position was efficiently synthesised. These compounds displayed fluorescence with maximum emission wavelengths of 673 and 685 nm, in anhydrous ethanol and water. All the benzo[a]phenoxazines were evaluated against the yeast Saccharomyces cerevisiae in a broth microdilution assay. It was found that their antifungal activity depended on the variation in the lengths of the aliphatic chains. The highest MIC activity of 1.56 µM was obtained for compound 7 comprising a di-alkylated propyl substituent at 9-amino position and a propyl chain at the 5-amino position of the heterocycle core.FEDER-COMPETE-QREN-EUFSEThanks are due to the Fundação para a Ciência e Tecnologia (FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centres CFUM [PEst-C/FIS/UI0607/2011 (F-COMP-01-0124-FEDER-022711)] and CQ/UM [PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716)]. A post-doctoral grant to B. R. Raju (SFRH/BPD/62881/2009) is also acknowledged to FCT, POPH-QREN, FSE. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01- 0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI).ERDFPOPH-QRENCOMPETE202
    corecore