671 research outputs found

    An integrated approach for assessing flood risk in historic city centres

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    Historic city centres near watercourses are a specific type of urban area that are particularly vulnerable to flooding. In this study, we present a new methodology of flood risk assessment that crosses hazard and physical vulnerability information. We have selected the Historic City Centre of Guimarães (Portugal), a UNESCO Heritage Site, for developing and testing the defined methodology. The flood hazard scenario was obtained through the hydrologic–hydraulic modelling of peak flows with a 100-year return period, which provided flood extent, depths, and velocities. A decomposition of the momentum equation, using depth and velocity, allowed reaching a final hazard score. Flood vulnerability was assessed through combining an exposure component and a sensitivity component, from field-collected data regarding wall orientation, heritage status, age, number of storeys, condition, and material of buildings. By combining the results of the hazard and vulnerability modules in a risk-matrix, three qualitative levels of flood risk were defined. The individual and crossed analysis of results proved to be complementary. On one hand, it allows the identification of the more relevant risk factors—from the hazard or vulnerability modules. On the other hand, the risk-matrix identified other buildings with a high risk that otherwise would remain unnoticed to risk managers.Tiago M. Ferreira is funded by the Portuguese Foundation for Science and Technology (FCT) through the postdoctoral grant SFRH/BPD/122598/2016 and Pedro P. Santos is funded through the project with the reference CEEIND/00268/2017

    Longitudinal study in 3,000 m male runners: relationship between performance and selected physiological parameters

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    The purpose of the present study was to analyze longitudinal changes in 3,000 m running performance and the relationship with selected physiological parameters. Eighteen well-trained male middle-distance runners were measured six times (x3 per year) throughout two consecutive competitive seasons. The following parameters were measured on each occasion: maximal oxygen uptake (VO2max), running economy (RE), velocity at maximal oxygen uptake (vVO2max), velocity at 4mmol L-1 blood lactate concentration (V4), and performance velocity (km·h-1) in 3,000 m time trials. Values ranged from 19.59 to 20.16 km·h-1, running performance; 197 to 207 mL·kg-1·km-1. RE; 17.2 to 17.7 km·h-1, V4; 67.1 to 72.5 mL·kg-1·min-1, VO2max; and 19.8 to 20.2 km·h-1, vVO2max. A hierarchical linear model was used to quantify longitudinal relationships between running performance and selected physiological variables. Running performance decreased significantly over time, between each time point the decrease in running velocity was 0.06 km·h-1. The variables that significantly explained performance changes were V4 and vVO2max. Also, vVO2max and V4 were the measures most strongly correlated with performance and can be used to predict 3,000 m race velocity. The best prediction formula for 3,000 m running performance was: y = 0.646 + 0.626x + 0.416z (R2=0.85); where y = V3,000 m velocity (km·h-1), x = V4 (km·h-1) and z = vVO2max (km·h-1). The high predictive power of vVO2max and V4 suggest that both coaches and athletes should give attention to improving these two physiological variables, in order to improve running performance

    Performance Assessment of ESP8266 Wireless Mesh Networks

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    This paper presents a wireless mesh network testbed based on ESP8266 devices using painlessMesh library. It evaluates its feasibility and potential effectiveness as a solution to monitor perishable goods, such as fresh fruit and vegetables, which are often stored and transported inside refrigerated containers. Performance testing experiments with different numbers of nodes and traffic loads and different message payload sizes are conducted under unicast transmission. The impact on network performance is evaluated in terms of delivery ratio and delivery delay, which, consequently, affect the energy consumption and, hence, network lifetime. The results of this investigation are an important contribution to help researchers to propose mechanisms, schemes, and protocols to improve performance in such challenging networks.info:eu-repo/semantics/publishedVersio

    Hypothyroidism decreases the biogenesis in free mitochondria and neuronal oxygen consumption in the cerebral cortex of developing rats

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    Thyroid hormone plays a critical role in mitochondrial biogenesis in two areas of the developing brain, the cerebral cortex and the striatum. Here we analyzed, in the cerebral cortex of neonatal rats, the effect of hypothyroidism on the biogenesis in free and synaptosomal mitochondria by analyzing, in isolated mitochondria, the activity of respiratory complex I, oxidative phosphorylation, oxygen consumption, and the expression of mitochondrial genome. In addition, we studied the effect of thyroid hormone in oxygen consumption in vivo by determining metabolic flow through C-13 nuclear magnetic resonance spectroscopy. Our results clearly show that in vivo, hypothyroidism markedly reduces oxygen consumption in the neural population of the cerebral cortex. This effect correlates with decreased free mitochondria biogenesis. In contrast, no effect was observed in the biogenesis in synaptosomal mitochondria. The parameters analyzed were markedly improved after T-3 administration. These results suggest that a reduced biogenesis and the subsequent reduction of respiratory capacity in free mitochondria could be the underlying cause of decreased oxygen consumption in the neurons of the cerebral cortex of hypothyroid neonates.This work was supported by Ministerio de Educaciín y Ciencia Grants SAF2004-06263-CO2-02 (to A.S.), SAF2004-06263-CO2-01, and SAF2007-62811 and Comunidad de Madrid Grant GR/SAL/0033/2004 (to A.P.-C.). Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas is funded by the Instituto de Salud Carlos III. T.B.R. is a recipient of a fellowship from the Fundaçâo para a Ciência e Tecnologia, Portugal (SFRH/BPD/26881/2006).Peer reviewe

    Patterns and drivers of rodent abundance across a South African multi-use landscape

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    Funding: This research was funded by FCT/MCTES, through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020 (cE3c: UIDB/00329/2020), and by the South African National Research Foundation, South Africa (UID 107099&115040). TAM thanks partial support by CEAUL (funded by FCT-Fundação para a Ciência e a Tecnologia, Portugal, through the project UIDB/00006/2020).South Africa’s decentralized approach to conservation entails that wildlife outside formally protected areas inhabit complex multi-use landscapes, where private wildlife business (ecotourism and/or hunting) co-exist in a human-dominated landscape matrix. Under decentralized conservation, wildlife is perceived to benefit from increased amount of available habitat, however it is crucial to understand how distinct management priorities and associated landscape modifications impact noncharismatic taxa, such as small mammals. We conducted extensive ink-tracking-tunnel surveys to estimate heterogeneity in rodent distribution and investigate the effect of different environmental factors on abundance patterns of two size-based rodent groups (small-and medium-sized species), across three adjacent management contexts in NE KwaZulu-Natal, South Africa: a private ecotourism game reserve, mixed farms and traditional communal areas (consisting of small clusters of houses interspersed with grazing areas and seminatural vegetation). Our hypotheses were formulated regarding the (1) area typology, (2) vegetation structure, (3) ungulate pressure and (4) human disturbance. Using a boosted-regression-tree approach, we found considerable differences between rodent groups’ abundance and distribution, and the underlying environmental factors. The mean relative abundance of medium-sized species did not differ across the three management contexts, but small species mean relative abundance was higher in the game reserves, confirming an influence of the area typology on their abundance. Variation in rodent relative abundance was negatively correlated with human disturbance and ungulate presence. Rodent abundance seems to be influenced by environmental gradients that are directly linked to varying management priorities across land uses, meaning that these communities might not benefit uniformly by the increased amount of habitat promoted by the commercial wildlife industry.Publisher PDFPeer reviewe

    Analysis of the dynamic air conditioning loads, fuel consumption and emissions of heavy-duty trucks with different glazing and paint optical properties

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    The European transportation sector employs 10 million people and accounts for 4.6% of the European Union GDP. Due to climate change, this workforce is increasingly affected by high temperatures and radiant loads, particularly during summer. They rely on air conditioning (AC) to minimize heat inside the truck cabins, increasing fuel consumption and tailpipe emissions. Because sustainable transportation is crucial for climate change mitigation, we developed a numerical investigation on the dynamic thermal exchanges of cabins of heavy-duty trucks in realistic conditions of a summer workday, to quantify the potential impact of interventions in the glazing and paint optical properties, over the truck AC loads. We observed that the changes in air temperature and solar irradiation throughout the workday imply substantial variations in the truck's AC loads and, consequently, in its fuel consumption and tailpipe emissions. Furthermore, windshields and side windows with transmissivity of 0.33 instead of typical 0.79 and 0.84, respectively, can reduce AC loads by up to 16%. External paints with reflectivity of 0.70 instead of 0.04 can reduce the AC loads by up to 30%, whereas cumulative changes to glazing and paint can reduce the AC load by up to 40%. These interventions can lower fuel consumption and emissions by up to 0.4%. These results show that important improvements in fuel efficiency and tailpipe emissions are possible, if the research community, policy makers and industry stakeholders successfully promote the adaptation of the European transportation fleet

    In-situ hot forging directed energy deposition-arc of CuAl8 alloy

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    Funding Information: Authors acknowledge the Portuguese Fundação para a Ciência e a Tecnologia ( FCT - MCTES ) for its financial support via the project UID/EMS/00667/2019 (UNIDEMI). VD acknowledges Portuguese Fundação para a Ciência e a Tecnologia ( FCT - MCTES ) for funding the PhD grant SFRH/BD/139454/2018 . TAR acknowledges Portuguese Fundação para a Ciência e a Tecnologia ( FCT - MCTES ) for funding the PhD grant SFRH/BD/144202/2019 . Funding of CENIMAT/i3N by national funds through the Portuguese Fundação para a Ciência e a Tecnologia, I.P., within the scope of Multiannual Financing of R&D Units , reference UIDB/50025/2020–2023 is also acknowledge. This activity has received funding from the European Institute of Innovation and Technology (EIT) Raw Materials through the project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. This body of the European Union receives support from the European Union's Horizon 2020 research and innovation programme. Parts of this research were carried out at PETRA III at DESY, a member of the Helmholtz Association. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020 . This project has received funding from the EU-H2020 research and innovation programme under grant agreement No 654360 having benefitted from the access provided by PETRA III at DESY in Hamburg, Germany within the framework of the NFFA-Europe Transnational Access Activity. The authors acknowledge support by OCAS NV and GUARENTEED via Joachim Antonissen. Funding Information: Authors acknowledge the Portuguese Fundação para a Ciência e a Tecnologia (FCT - MCTES) for its financial support via the project UID/EMS/00667/2019 (UNIDEMI). VD acknowledges Portuguese Fundação para a Ciência e a Tecnologia (FCT - MCTES) for funding the PhD grant SFRH/BD/139454/2018. TAR acknowledges Portuguese Fundação para a Ciência e a Tecnologia (FCT - MCTES) for funding the PhD grant SFRH/BD/144202/2019. Funding of CENIMAT/i3N by national funds through the Portuguese Fundação para a Ciência e a Tecnologia, I.P. within the scope of Multiannual Financing of R&D Units, reference UIDB/50025/2020–2023 is also acknowledge. This activity has received funding from the European Institute of Innovation and Technology (EIT) Raw Materials through the project Smart WAAM: Microstructural Engineering and Integrated Non-Destructive Testing. This body of the European Union receives support from the European Union's Horizon 2020 research and innovation programme. Parts of this research were carried out at PETRA III at DESY, a member of the Helmholtz Association. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. This project has received funding from the EU-H2020 research and innovation programme under grant agreement No 654360 having benefitted from the access provided by PETRA III at DESY in Hamburg, Germany within the framework of the NFFA-Europe Transnational Access Activity. The authors acknowledge support by OCAS NV and GUARENTEED via Joachim Antonissen. Remark: The supplementary material is temporarily available in the Drive folder here: https://drive.google.com/drive/folders/1SFFlhJlmL5p3IkQis8cB6UVWva3wozGi?usp=sharing. Publisher Copyright: © 2022 Elsevier B.V.CuAl8 alloy finds applications in industrial components, where a good anti-corrosion and anti-wearing properties are required. The alloy has a medium strength and a good toughness with an elongation to fracture at room temperature of about 40%. Additionally, it has a good electrical conductivity, though lower than that of pure Al or pure Cu. Despite these characteristics, additive manufacturing of the CuAl8 alloy was not yet reported. In this work, the direct energy deposition-arc (DED-arc) with and without in-situ hot forging was used to determine the microstructure evolution and mechanical properties. No internal defects were seen on the parts produced. Hot forging combined with DED-arc was seen to reduce and homogenize the grain size, improve mechanical strength and isotropy of mechanical properties. Moreover, the use of this novel DED-arc variant was seen to reduce the magnitude of residual stresses throughout the fabricated part. We highlight that this alloy can be processed by DED-arc, and the hot forging operation concomitant with the material deposition has beneficial effects on the microstructure refinement and homogenization.publishersversionpublishe
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