742 research outputs found

    Results of DEC Unit Assisted by Solar Energy in Lisbon

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    The Air Handling Unit (AHU) with Desiccant Evaporative Cooling (DEC) technology, assisted by solar energy, is in operation at LNEG (former INETI) since 1999, ant it has some features in its design, resulting from local constraints of the building and from design decisions taken at that time with the purpose to investigate different solutions. This unit has a conventional auxiliary back-up cooling unit, an heat pump, to assist the DEC AHU on cold production in heavy summer load conditions, that guarantees the comfort conditions of the 12 offices, but does not permit an high solar fraction in summer due to the role of its condenser. So, to limit the time operation period of the heat pump, was recently introduced a new humidifier in the air admission section. In this paper we make a description of this AHU and we report the results obtained so far after those modifications, in a qualitative way, and we begin the discussion of using the performance figures, adopted in the framework of IEA SHC Task 38, to this unit

    Comparison of a rapid test and an automated method for faecal calprotectin measurement

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    n/aWe acknowledge Arium Diagnostics Systems LDA (Bühlmann Laboratories AG representative in Portugal) for its support in providing fCAL® Turbo tests and controls. Arium did not play any role in study design, execution, analysis or interpretation of the data

    Geochemistry of granitic aplite-pegmatite veins and sills and their minerals from the Sabugal area, central Portugal

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    Granitic beryl-columbite-phosphate subtype aplite-pegmatite veins and sills from the Sabugal area intruded a biotite > muscovite granite which is related to another two-mica granite. Variation diagrams of major and trace elements of whole rocks show fractionation trends. REE patterns and δ18O of whole rocks, BaO and P2O5 contents of K-feldspar, anorthite and P2O5 contents of plagioclase, major element and Li contents of muscovite and lithian muscovite support this series. Least squares analysis of major elements indicate that the biotite > muscovite granite and aplite-pegmatite veins and sills are derived from the earlier two-mica granite magma by fractional crystallization of quartz, plagioclase, K-feldspar, biotite and ilmenite. Modelling of trace elements shows that magmatic fl uxes and fl uids controlled the Rb, Sr and Ba contents of aplite-pegmatites, probably also lithium micas (zinnwaldite, polylithionite and rare lepidolite), cassiterite, columbite-tantalite, fl uorapatite and triplite. In aplite-pegmatites, lithian muscovite replaces primary muscovite and late lithium micas replace lithian muscovite. Complexely zoned columbite crystals are chemically characterized and attributed to disequilibrium conditions. Relations of granites and aplite-pegmatites and pegmatites from other Portuguese and Spanish areas are compared. The granitic aplite-pegmatites from Sabugal are moderately fractionated and the granitic complex type aplite-pegmatites from Gonçalo are the richest in Li and Sn, derived from a higher degree of fractional crystallization and fl uxes and fl uids control the Ba and Rb behaviours and Li, Sn, F and Ta concentrations

    Micas litiníferas dos aplito-pegmatitos graníticos de Cabeço dos Poupos, Sabugal (Centro de Portugal) = Lithium micas of granitic aplite-pegmatites from Cabeço dos Poupos, Sabugal (Central Portugal)

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    Na região de Cabeço dos Poupos (Sabugal, centro de Portugal) afloram várias soleiras e filões aplito-pegmatíticos, com assinaturas mineralógica e geológica típicas de pegmatitos REL-Li, que se integram no subtipo berilo-columbite-fosfato. Trata-se de aplito-pegmatitos de elementos raros com um grau moderado de evolução geoquímica. A moscovite primária é facilmente reconhecida, do ponto de vista textural e geoquímico, como constituindo a mica dominante nos aplito-pegmatitos desta região. Contudo, também ocorre moscovite litinífera e zinvaldite tabular, de cristalização precoce. Em alguns destes filões, reconheceu-se a presença de micas tardias, com composições de moscovite litinífera, zinvaldite, lepidolite e polilitionite. Em geral, as micas litiníferas tardias mostram contactos bruscos com as micas mais precoces. As micas litiníferas revelaram teores de Fe+Mg, Li, Rb e F mais elevados do que a moscovite primária, sendo, por outro lado, mais empobrecidas em AlVI, AlIV+AlVI e OH

    Geoquímica de soleiras e filões aplito-pegmatíticos graníticos do centro de Portugal : cristalização fraccionada, fluxos e fluídos

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    As soleiras e filões aplito-pegmatíticos graníticos de Arcozelo da Serra, Cabeço dos Poupos (Sabugal) e Gonçalo (Belmonte) podem ser derivados por cristalização fraccionada de quartzo, plagioclase, feldspato potássico e biotite de um magma de granito da área respectiva, o que foi testado por modelização, usando o método de regressão de mínimos quadrados para os elementos maiores e a equação de cristalização fraccionada perfeita para os elementos menores. Há aumento no grau de evolução dos aplito-pegmatitos de Arcozelo da Serra para os de Cabeço dos Poupos e destes para os de Gonçalo, pois há aumento progressivo na quantidade e número de minerais litiníferos. Os aplitopegmatitos graníticos do subtipo lepidolítico são os mais evoluídos e derivam de um maior grau de cristalização fraccionada, sendo os mais ricos em fluxos (H2O, F, P, B) e fluidos. Com o aumento do grau de evolução dos aplitopegmatitos diminui o efeito dos fluxos e fluidos nos teores de Sr e Ba, mas aumentou esse efeito no teor de Rb. A cristalização fraccionada causou aumento nos teores de Rb, Li, F, Sn e Ta nos aplito-pegmatitos graníticos, especialmente nos do subtipo lepidolítico e os fluxos e fluidos influenciaram a cristalização de lepidolite, cassiterite e óxidos de Nb-Ta

    Long-range dependencies of euronext capital markets: A dynamic detrended analysis

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    This paper aims to test efficiency, in its weak form, in the capital markets of the Netherlands (AEX), Belgium (BEL 20), France (CAC 40), Ireland (ISEQ 20), Norway (OSEBX), Portugal (PSI 20), in the period from April 4, 2019 to April 1, 2021. The sample was partitioned into two subperiods, the first and second wave of the global pandemic: April 4, 2019 to April 30, 2020; May 4, 2020 to April 1, 2021. To carry out this analysis, different approaches were undertaken to analyze whether: (i) Euronext’s stock markets have more significant long memories in the first or second wave of the global pandemic? The results show the presence of sharp long memories during the first wave of the global pandemic, particularly in the stock indices OSEBX (0.67), PSI 20 (0.67), AEX (0.66), BEL 20 (0.64), CAC 40 (0.62), ISEQ 20 (0.61), which implies that the yields are autocorrelated in time and, there is a reversal of the average, in all indexes. Regarding the second wave of the global pandemic, we found that most Euronext stock markets don’t reject the random walk hypothesis, with the exception of the Norwegian (0.56) and Portugal (0.55) stock markets. These findings show that the impact of the Covid-19 pandemic was accentuated during the first wave, but from May 2020 the markets adjusted and showed balance. The authors believe that the results achieved will be a benefit to international investors seeking efficient diversification into their portfolios.info:eu-repo/semantics/publishedVersio
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