62 research outputs found

    Fused Filament Fabrication over fabrics: experiments and applications

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    The focus of this paper is to explore the use of Fused Filament Fabrication technology, a material extrusion additive manufacturing technology, by depositing melted Polilactic Acid (PLA) over a substrate – fabric - instead of on an empty building tray. The textile’s composition, nozzle and building plate temperature, printed PLA thickness and printed geometry have been considered as variables that could influence the structural and adhesion properties on this study so, therefor, were took into consideration and tested throughout the printing process through specimens printed with different combined parameters. The aim of this exploration process was developing an experimental procedure to study the limitations and capabilities of this printing technology over textiles, and which different variables’ combination would contribute to a better overall result in the development of a self-supporting textile based structural model, that could be apply in different contexts without the need of any extra external support. Results showed that PLA adherence to the fabric is correlated with nozzle/building plate temperature and printing thickness: higher temperature and thickness provide higher adherence. The weave of the textile didn´t reflect on better results but the polyester felt fabric exhibit maximum adherence with printed PLA in all sets of temperatures. In addition, geometries with reinforcement lines along the fabric stress direction provided better structural results. These results enable new application possibilities for the FFF technology combined in fabrics such as in interior, fashion and shoe ware design.publishe

    Paleolítico médio em Galapos (Arrábida)

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    Descrevem-se artefactos líticos de quartzo (e sílex) recolhidos em Galapos (Creiro), na vertente meridional da Serra da Arrábida. São característicos do Paleolítico médio (Mustierense) e reforçam a evidência da importante ocupação humana da região, já salientada pelo estudo da gruta da Figueira Brava.info:eu-repo/semantics/publishedVersio

    Miocene sediments from Foz da Fonte and Penedo sections (Lower Tagus basin): clay minerals and isotopic data

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    Eight depositional sequences (DS) delimited by regional disconformities had been recognized in the Miocene of Lisbon and Setúbal Peninsula areas. In the case of the western coast of the Setúbal Peninsula, outcrops consisting of Lower Burdigalian to Lower Tortonian sediments were studied. The stratigraphic zonography and the environmental considerations are mainly supported on data concerning to foraminifera, ostracoda, vertebrates and palynomorphs. The first mineralogical and geochemical data determined for Foz da Fonte, Penedo Sul and Penedo Norte sedimentary sequences are presented. These analytical data mainly correspond to the sediments' fine fractions. Mineralogical data are based on X-ray diffraction (XRD), carried out on both the less than 38 nm and 2 nm fractions. Qualitative and semi-quantitative determinations of clay and non-clay minerals were obtained for both fractions. The clay minerals assemblages complete the lithostratigraphic and paleoenvironmental data obtained by stratigraphic and palaeontological studies. Some palaeomagnetic and isotopic data are discussed and correlated with the mineralogical data. Multivariate data analysis (Principal Components Analysis) of the mineralogical data was carried out using both R-mode and Q-mode factor analysis

    Dois exemplos de tectónica pós-rifting da Bacia Lusitaniana

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    A Cadeia da Arrábida é a estrutura morfotectónica orogénica, constituída por empilhamentos de cavalgamentos, mais ocidental de todo o orógeno alpino da área emersa da placa litosférica Eurásia. Atentando apenas nos relevos orogénicos alpinos da área emersa de Portugal, as suas estruturas e morfologia tornam-na no mais elegante exemplo de tectónica orogénica alpina em Portugal. A Serra de Sintra constitui um relevo associado à intrusão do Complexo Ígneo de Sintra de idade neo-cretácica e ao cavalgamento frontal de idade cenozóica, com vergência para Norte que se estende desde as proximidades do rio Tejo, passando pela base da vertente norte da Serra de Sintra, continuando mar adentro. Olhando para a continuação imersa da Margem Continental Portuguesa vê-se que estes relevos não estão isolados, mas antes fazem parte dum grupo de três outras estruturas compressivas que acomodaram o encurtamento orogénico resultante da colisão África-Eurásia ocidentais no segmento sudoeste ibérico, o Banco do Gorringe, os Montes de Avis e o Planalto de Marquês de Pombal. Todas estas estruturas se constituem como estruturas anticlinais, mais ou menos simples, a tecto dum cavalgamento com transporte para noroeste ou oeste-noroeste. Na face meridional de Portugal, mais próxima do limite de placas, as estruturas de deformação compressiva resultantes da orogenia alpina encontram-se representadas na Bacia do Algarve e, mais a sul, pelo Banco do Guadalquivir. Todas estas estruturas se formaram no âmbito da orogenia alpina, consequência dum contexto cinemático de aproximação das placas litosféricas Eurásia e África, cujas manifestações morfotectónicas e sedimentares se começaram a manifestar no Cretácico Superior após o Cenomaniano. A distribuição espacio-temporal da deformação orogénica no segmento mais ocidental do orógeno é heterogénea e extremamente complexa. Por exemplo, em Portugal – segmento autóctone do orógeno alpino - as principais estruturas compressivas alpinas mais antigas datam do Cretácico superior e na região de Lisboa-Sintra de idade paleogénica. Contudo as estruturas de maior envergadura morfológica são de idade miocénica (serra da Arrábida, Banco do Gorringe, Montes de Avis) e mesmo de reactivação mais recente (Falha e planalto do Marquês de Pombal, Falha da Ferradura e Banco de Guadalquivir. A mesma heterogeneidade espacio-temporal se verifica em segmentos alóctones como no orógeno Bético-Rifenho, cujo arco orogénico frontal se vem propagando para oeste desde o Cretácico superior, simultaneamente cavalgando para norte e para sul, as margens continentais do sul de Espanha e norte de África. Esta migração orogénica está simultaneamente associada a colapso orogénico e distensão nas áreas internas do orógeno (Mar de Alborán), o que tem constituído um dos paradoxos da deformação orogénica alpina mais desafiantes das últimas décadas e para cuja solução se têm proposto mecanismos de delaminação tectónica da base da litosfera ou retro-rolamento da placa subductada

    Índice de distorção, parâmetros celulares e composição química de cordierite de granitóides e corneanas da região de Tondela - Oliveira do Hospital (Portugal Central)

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    Memórias e Noticias, PubI. Mus. Lab. Mineral. Geol., Univ. Coimbra, n.O 116, 1993Distortion index, cell parameters and chemical composítíon of cordíerites from granites and hornfelses of the Tondela-Oliveira do Hospital region (Central Portugal). Distortion index was measured and cell parameters calculated for cordierite samples from porphyritic granites (4 samples), pegmaplites (2) and contact peliiic hornfelses (13). Distortion index range is 0.14-0.26 with a low mean value 0.19 for granitic rocks; with one exception (distortion index 0.14), this index range between 0.22 and 0.26 in cordierite from hornfelses, with no apparent relation to the dista.nce from the contacto Cell parameters do not significantly discriminate the occurrences of cordierite, and the calculation fits orthorrombic sym.etry in ali samples, Electron microprobe chemical composition of 14 cordierite samples is presented; its probable relation to AI/Si order and rock type is discussed

    Biostratigraphic calibration of seismic units in the offshore Algarve Basin: contribution of core SWIM04-39

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    [RESUMO] Efectuou-se a calibração estratigráfica das unidades sísmicas mais recentes identificadas na Bacia offshore do Algarve recorrendo à análise biostratigráfica (Nanofósseis calcários e Foraminíferos) do core de pistão SWIM04-39. Obteve-se uma idade de cerca de 4.0 Ma (Pliocénico Inferior, Zancliano) para as associações fitoplanctónica e faunística presente nas amostras do referido core. Estes dados permitiram datar o início da intensa subsidência sofrida por esta Bacia como sendo Pliocénico Inferior. [ABSTRACT] Biostratigraphic calibration of the seismic units recognized in the offshore Algarve Basin was made, based on the identification of Calcareous nanofossil and Foraminifera assemblages present in the core SWIM04-39. An age of about 4.0 Ma (Early Pliocene, Zanclean) was determinate for these assemblages. Using this data is possible to place the beginning of subsidence movements in the offshore Algarve Basin during the Early Pliocene.publishersversionpublishe

    Magnesium Accumulation in Two Contrasting Varieties of Lycopersicum esculentum L. Fruits: Interaction with Calcium at Tissue Level and Implications on Quality

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    As the productivity and quality of tomato fruits are responsive to Mg applications, without surpassing the threshold of toxicity, the assessment of potential levels of Mg accumulation in tissues, as well as the interactions with Ca and physicochemical properties, prompt this study. An agronomic workflow for Mg enrichment, consisting of six foliar applications of MgSO4 with four concentrations (0%, 0.25%, 1% and 4%), equivalent to 0, 43.9, 175.5 and 702 g ha-1 , was applied on two tomato (Lycopersicum esculentum L.) genotypes (Heinz1534 and Heinz9205). During fruit development, leaf gas exchange was screened, with only minor physiological deviations being found. At harvest, Mg contents among tissues and the interactions with Ca were analyzed, and it was found that in both varieties a higher Mg/Ca ratio prevailed in the most external part of the fruit sprayed with 4% MgSO4. However, Mg distribution prevailed relatively near the epidermis in H1534, while in H9205 the higher contents of this nutrient occurred in the core of the fruit, which indicated a decrease of the relative proportion of Ca. The morphologic (height and diameter), physical (dry weight and density) and colorimetric parameters, and the total soluble solids of fruits, did not reveal significant changes in both tomato varieties. It was further concluded that foliar application until 4% MgSO4 does not have physiological impacts in the fruit’s quality of both varieties, but in spite of the different patterns of Mg accumulation in tissues, if the mean value in the whole fruit is considered, this nutrient prevails in H1534. This study thus suggests that variety H1534 can be used to attain tomato fruits with added value, providing an option of further processing to achieve food products with functional properties, ultimately proving a beneficial option to producers, the food processing industry and consumers. Moreover, the study reinforces the importance of variety choice when designing enrichment workflowsinfo:eu-repo/semantics/publishedVersio

    Macaronesia Acts as a Museum of Genetic Diversity of Relict Ferns: The Case of Diplazium caudatum (Athyriaceae)

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    Macaronesia has been considered a refuge region of the formerly widespread subtropical lauroid flora that lived in Southern Europe during the Tertiary. The study of relict angiosperms has shown that Macaronesian relict taxa preserve genetic variation and revealed general patterns of colonization and dispersal. However, information on the conservation of genetic diversity and range dynamics rapidly diminishes when referring to pteridophytes, despite their dominance of the herbaceous stratum in the European tropical palaeoflora. Here we aim to elucidate the pattern of genetic diversity and phylogeography of Diplazium caudatum, a hypothesized species of the Tertiary Palaeotropical flora and currently with its populations restricted across Macaronesia and disjunctly in the Sierras de Algeciras (Andalusia, southern Iberian Peninsula). We analysed 12 populations across the species range using eight microsatellite loci, sequences of a region of plastid DNA, and carry out species-distribution modelling analyses. Our dating results confirm the Tertiary origin of this species. The Macaronesian archipelagos served as a refuge during at least the Quaternary glacial cycles, where populations of D. caudatum preserved higher levels of genetic variation than mainland populations. Our data suggest the disappearance of the species in the continent and the subsequent recolonization from Macaronesia. The results of the AMOVA analysis and the indices of clonal diversity and linkage disequilibrium suggest that D. caudatum is a species in which inter-gametophytic outcrossing predominates, and that in the Andalusian populations there was a shift in mating system toward increased inbreeding and/or clonality. The model that best explains the genetic diversity distribution pattern observed in Macaronesia is, the initial and recurrent colonization between islands and archipelagos and the relatively recent diversification of restricted area lineages, probably due to the decrease of favorable habitats and competition with lineages previously established. This study extends to ferns the concept of Macaronesia archipelagos as refugia for genetic variation

    Implications on Mineral Elements, Sugars and Fatty Acids Accumulation in Tissues

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    Funding Information: This work received funding from PDR2020-101-030734 and Fundação para a Ciência e a Tecnologia, I.P. (FCT), Portugal, through the research units UIDB/04035/2020 (GeoBioTec), UIDB/00239/2020 (CEF) and UID/FIS/04559/2020 (LIBPhys) from the FCT/MCTES/PIDDAC. This work was further supported by the grant of Fundação para a Ciência e Tecnologia (FCT) UI/BD/150718/2020. Publisher Copyright: © 2022 by the authors.Following an agronomic approach for the Ca enrichment of Rocha pears, this study aimed to assess the interactions between mineral nutrients in fruit tissues at harvest and after storage for 5 months and to characterize the implications on the profile of sugars and fatty acids (FA). A total of seven foliar sprays (with concentrations of 0.1–0.6 kg·ha−1 Ca(NO3)2 and 0.8–8 kg·ha−1 CaCl2) were applied to pear trees. After harvest, the fruits were stored for 5 months, in environmentally controlled chambers, and the mineral contents in five regions (on the equatorial section) of the fruits were assessed, while the sugar and FA content were quantified. For both dates, all foliar sprayed treatments, at different extends, increased Ca content in the center and near the epidermis of Rocha pear fruits and the levels of K, Mn, Fe, Zn and Cu also varied. At harvest, the Ca treatments did not affect the levels of sucrose, glucose, fructose and sorbitol and, after storage, their concentrations remained higher in Ca-treated fruits. Additionally, the tendency of the relative proportions of FA was C18:2 > C18:1 > C16:0 > C18:3 > C18:0 > chains inferior to 16 C ( C16:0 > C18:3 > C18:0 > C18:1 > chains inferior to 16 C (<16:0). It is concluded that the heterogeneous distribution of Ca in the tissues of Rocha pear fruits results from its absorption in the peel after Ca(NO3)2 and CaCl2 sprays and from the xylemic flux in the core prior to maturity. Additionally, the hydrolysis of complex polysaccharides affects the contents of simpler sugars during maturation, ripening and senescence, while storage decreases the amount of total fatty acids (TFA), but the double bond index (DBI) indicate that cell membrane fluidity remains unaffected.publishersversionpublishe
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