2,249 research outputs found

    The pinewood nematode, Bursaphelenchus xylophilus, in Madeira Island

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    The environmental conditions in Madeira Island are favorable for the presence and dissemination of the pinewood nematode (PWN), Bursaphelenchus xylophilus. Five hundred Pinus pinaster wood samples were collected in several forest areas and PWN was detected in 22.8 % of the samples. Bursaphelenchus xylophilus isolates from Madeira Island displayed the species-specific diagnostic characters. A morphological variation in the female tail terminus was detected. In most females, the tail presented a broadly rounded terminus and, occasionally, a digitate terminus with a terminal nipple-like extension resembling a mucro. PCR ITS-RFLP analysis revealed that Madeira Island isolates exhibited patterns specific to the species B. xylophilus and similar to virulent isolates. Amplified ITS regions were further sequenced and no genetic diversity was found for this genomic region among 17 Portuguese isolates (Madeira Island and Continental Portugal). Phylogenetic analysis revealed that Portuguese isolates grouped with isolates from China, Korea and one isolate from Japa

    Discovering the colours of industrial heritage characterisation of paint coatings from the powerplant at the Levada de Tomar

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    The paint coatings of three energy generators from the 20th-century powerplant at Levada de Tomar, Portugal, were investigated using micro-Raman and micro-X-ray fluorescence spectroscopies and scanning electron microscopy with energy dispersive spectroscopy. This multi-analytical approach was used to identify the colouring agents, thus providing a chronological chromatic pallet and allowing to infer on the use of the three energy generators. Together with traditional pigments like Prussian blue, red iron oxide, and carbon black, pigments used in industrial areas like copper phthalocyanine and toluidine red were identified as colouring agents. Complex paint systems of the oldest equipment (1924) were revealed as well as maintenance procedures of the equipment that worked during a longer time (1944–1990). Powdery carbon black layers, resulting from incomplete hydrocarbon combustion and present between metallic substrates and coating layers, suggested the inexistence of paint coatings replacement after the powerplant shutdown. The identification of magnetite as a corrosion product of iron alloy substrate revealed that corrosion developed after the engine shutdown and not during the operation period. The results obtained highlight the potentialities of scientific-based approach and Raman spectroscopy to the industrial heritage study, an emergent cultural area.publishersversionpublishe

    Recycled asphalt mixtures produced with high percentage of different waste materials

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    The use of sustainable solutions in construction is not just an option, but is increasingly becoming a need of the Society. Thus, nowadays the recycling of waste materials is a growing technology that needs to be continuously improved, namely by researching new solutions for waste valorisation and by increasing the amount of wastes reused. In the paving industry, the reuse of reclaimed asphalt (RA) is becoming common practice, but needs further research work. Thus, this study aims to increase the incorporation of RA and other waste materials in the production of recycled asphalt mixtures in order to improve their mechanical, environmental and economic performance. Recycled mixtures with 50% RA were analysed in this study, including: i) RA selection, preparation and characterization; ii) incorporation of other waste materials as binder additives or modifiers, like used motor oil (UMO) and waste high density polyethylene (HDPE); iii) production of different mixtures (without additives; with UMO; with UMO and HDPE) and comparison of their performance in order to assess the main advantages of each solution. With this study it was concluded that up to 7.5 % of UMO and 4.0 % of HDPE can be used in a new modified binder for asphalt mixtures with 50 % of RA, which have excellent properties concerning the rutting with WTS = 0.02 mm/103 cycles, the fatigue resistance with ε6 = 160.4, and water sensitivity with an ITSR of 81.9 %.The authors would like to acknowledge the financial and material support given by some institutions. In fact, this work was funded by FEDER funds through the Operational Competitiveness Program – COMPETE and by National funds by FCT – Portuguese Foundation for Science and Technology in the scope of Project FCOMP-01-0124-FEDER-020335 (PTDC/ECM/119179/2010) and the Project SI Innovation 7603, as well as the FCT PhD grant SFRH/BD/85448/2012. Thanks are also due to the Companies Gintegral (for the supply of recycled HDPE) and CEPSA (for the supply of bitumen)

    Portuguese nurses’ stress, anxiety, and depression reduction strategies during the COVID-19 outbreak

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    The COVID-19 pandemic has contributed to mental health problems worldwide. Nurses are particularly prone to stress because they directly care for individuals with suspected or confirmed cases of COVID-19. The aims of this study were (a) to explore the association between the mental health promotion strategies used by nurses during the COVID-19 outbreak and their symptoms of depression, anxiety, and stress; (b) to compare the symptoms of depression, anxiety, and stress of mental health nurses to those of non-mental health nurses; and (c) to compare the frequency of use of mental health strategies of mental health nurses to those of non-mental health nurses. A cross-sectional study was conducted with a sample of 821 nurses. Univariate and multivariate regression models were developed to identify potential protective factors of depression, anxiety, and stress. The chi-square test was also used to compare the use of strategies among mental health and non-mental health nurses. Portuguese nurses demonstrated high symptoms of depressive symptoms, stress, and anxiety. Healthy eating, physical activity, rest between shifts, maintaining social contacts, verbalizing feelings/emotions, and spending less time searching for information about COVID-19 were associated with better mental health. Mental health nurses had less depression, anxiety, and stress, and used more strategies to promote mental health than other nurses. We consider it important to promote nurses’ mental health literacy by encouraging them to develop skills and strategies aimed at improving their resilience and ability to deal with difficult situations while caring for the population.info:eu-repo/semantics/publishedVersio

    A micromachined thermoelectric sensor for natural gas analysis: Multivariate calibration results

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    The potential use of a micromachined thermopile based sensor device for analyzing natural gas is explored. The sensor consists of a thermally isolated hotplate, which is heated by the application of a sequence of programmed voltages to an integrated heater. Once the hotplate reaches a stationary temperature, the thermopile provides a signal proportional to the hotplate temperature. These signals are processed in order to determine different natural gas properties. Sensor response is mainly dependent on the thermal conductivity of the surrounding gas at different temperatures. Seven predicted properties (normal density, superior heating value, Wobbe index and the concentrations of methane, ethane, carbon dioxide and nitrogen) are calibrated against sensor signals by using multivariate regression, in particular partial least squares. Experimental data have been used for calibration and validation. Results show property prediction capability with reasonable accuracy except for prediction of carbon dioxide concentration. A detailed uncertainty analysis is provided to better understand the metrological limits of the system. These results imply for the first time the possibility of designing unprecedented low-cost natural gas analyzers. The concept may be extended to other constrained gas mixtures (e.g. of a known number of components) to enable low-cost multicomponent gas analyzers

    Avaliação de estruturas de pavimentos rodoviários através de pista e simulador de ensaios acelerados à escala real

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    Os ensaios acelerados de pavimentos rodoviários consistem na aplicação controlada de um carregamento vertical, através de uma roda normalizada que circula a uma velocidade controlada, simulando as cargas reais introduzidas pelo tráfego pesado. Em condições de temperatura e humidade controladas, os ensaios acelerados permitem simular num período de tempo reduzido as ações a que um pavimento está sujeito ao longo da sua vida útil. No âmbito do Projeto Tropical-PAV foi construída no LNEC uma pista de ensaios à escala real e instalado um Simulador de Ensaios Acelerados sobre Pavimentos Rodoviários possibilitando o estudo e a validação de técnicas de construção e/ou reabilitação de pavimentos rodoviários. No presente trabalho é feita uma apresentação geral dos ensaios acelerados sobre pavimentos rodoviários e em particular do Projeto de I&D Tropical-PAV.Quadro de Referência Estratégica Nacional e à entidade financiadora Agência Nacional da Inovação pelo financiamento ao projeto número 38915 Projeto de I&D Tropical-PA

    Soluções de pavimentos rodoviários para países com climas tropicais – projeto de I&D tropical-PAV

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    Algumas empresas do setor da construção que integram a Plataforma Tecnológica Portuguesa da Construção (PTPC) decidiram promover a cooperação tecnológica entre si e com as entidades do Sistema Científico e Tecnológico Nacional (SCTN) para o desenvolvimento de novas soluções de pavimentação rodoviária para aplicação em países de clima tropical, nomeadamente ao nível das misturas betuminosas e das camadas de solocimento. O objetivo do projeto foi permitir a eventual criação de uma solução de pavimentação inovadora através do desenvolvimento de uma mistura betuminosa e de uma mistura de solo-cimento formuladas com base em ensaios empíricos e de desempenho, à escala laboratorial e, posteriormente, validando esse desempenho num ensaio à escala real recorrendo a uma Pista de Ensaios Acelerados de Pavimentos, onde foram aplicados carregamentos idênticos às solicitações que serão alvo ao longo do seu período de vida útil. Esta Pista de Ensaios Acelerados de Pavimentos construída no âmbito deste projeto integra um protótipo de um simulador de tráfego, que reproduz a simulação do tipo de solicitação a que um pavimento habitualmente está sujeito

    The use of mental health promotion strategies by nurses to reduce anxiety, stress, and depression during the COVID-19 outbreak: a prospective cohort study

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    Objectives: To evaluate and compare nurses' depression, anxiety and stress symptoms at the beginning of the COVID-19 pandemic and after six months; to evaluate and compare the frequency of use of mental health promotion strategies during the same period; and to identify the relationship between the frequency of use of mental health promotion strategies, during the same period, with nurses’ depression, anxiety and stress symptoms. Methods: Data collection was carried out in two moments: at baseline and after six months. An online questionnaire was applied to nurses to assess the frequency of use of some mental health promotion strategies and their depression, anxiety, and stress symptoms (through the Depression Anxiety Stress Scales – short version (DASS-21)). Results: The anxiety and stress symptoms significantly decreased over time. The physical activity increased, and a decrease was observed in the remote social contacts after six months. The stress, anxiety and depression scores were significantly lower in nurses who frequently or always used all strategies compared to participants who never or rarely used them, except for one strategy (rejecting information about COVID-19 from unreliable sources). Conclusions: Mental health promotion strategies, such as physical activity, relaxation activity, recreational activity, healthy diet, adequate water intake, breaks between work shifts, maintenance of remote social contacts, and verbalization of feelings/emotions, are crucial to reduce nurses’ stress, anxiety and depression symptoms during the COVID-19 outbreak.info:eu-repo/semantics/publishedVersio

    Fenton-type bimetallic catalysts for degradation of dyes in aqueous solutions

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    Dye compounds are becoming a problematic class of pollutants for the environment, so it is important to develop stable catalysts for their elimination. First, several studies were performed with different Y zeolites (NaY, (NH4)Y and USY) in order to select the best support for the preparation of the bimetallic catalysts. In particular, NaY zeolite was used as the support for Fe, Cu and Mn metals to prepare mono and bimetallic Fenton-type catalysts by the ion exchange method. The catalysts were characterized by several techniques, such as chemical analysis, nitrogen physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry studies. Characterization results revealed that the metals were successfully ion-exchanged within the NaY zeolite. The prepared catalysts were tested for the aqueous-phase degradation of dye compounds (Procion yellow (PY) and Tartrazine (Tar)) at atmospheric pressure and different temperatures, using H2O2 as the oxidant. All the investigated samples were found to be active in degrading the dyes through the Fenton-type process; however, the oxidation rate was found to be higher in the presence of the bimetallic catalysts. CuFe-NaY displays the best mineralization rate for PY oxidation while MnFe-NaY shows the highest activity for Tar degradation. This work may provide further insight into the design of Fenton-type bimetallic catalysts with improved catalytic properties for environmental remediation.This research work has been developed under the scope of the projects: BioTecNorte (operation NORTE-01-0145-FEDER-000004), supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work also has been funded by national funds (Fundação para Ciência e Tecnologia, FCT), through the projects: PTDC/AAGTEC/5269/2014, Centre of Chemistry (UID/QUI/00686/2013 and UID/QUI/0686/2016) and Associate Laboratory LSRE-LCM-UIDB/50020/2020. OSGPS acknowledges FCT funding under the Scientific Employment Stimulus—Institutional Call CEECINST/00049/2018.info:eu-repo/semantics/publishedVersio
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