1,159 research outputs found

    3D printing of flexible conductive polymers on textiles for sensing and electrical connection

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    Additive manufacturing (AM) is a 3D printing technology that works by deposition of a material, layer by layer, creating 3D objects. The growth of these technologies has been exponential and the application of AM in the textile industry has also been a subject of increased interest in the past few years. The applications are not only for decorative purposes, but also for biomedical and other uses in e-textiles. However, a crucial point for making such assembly is the adhesion between the material and the textile substrate, as well as the premise of meeting demanding wash resistance requirements. This work aims to investigate the possibility of creating sensors by combining textiles with conductive polymeric filaments used in 3D printing. Merging the flexibility of use, mechanical properties and electrical conductivity of the polymeric filaments with the comfort and physical properties of the textiles can be a promising approach to create novel sensing structures. In this document, we give an overview of the recent state of the art of experimental research on adhesion in textile and polymer composites as well as an optimization of the printing parameters with a conductive filament, PI-ETPU. Some results from the printed samples in terms of print quality and electrical resistance are presented. Combining both topics, further work will include printing with conductive filament on textile substrates to study the possibly of creating sensing and electrical connections.FCT - Fundação para a Ciência e a Tecnologia(undefined

    Effects of substituting ytterbium for scandium on the microstructure and age-hardening behaviour of Al–Sc alloy

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    In order to reduce the cost of Al–Sc alloys and maintain their mechanical properties, the microstructure and mechanical properties of Al–0.24 wt% Sc–0.07 wt% Yb in comparison with Al–0.28 wt% Sc alloys were studied. The aging behaviour, precipitate morphologies, precipitate coarsening and precipitation hardening of both alloys were investigated. The average diameter and the size distribution of nanoscale Al3Sc and Al3(Sc,Yb) precipitates at various aging conditions were measured. Transmission electron microscopy (TEM) and high-resolution TEM were used to deeply understand the precipitate evolution. A maximum hardness around 73 (HV30) was obtained with a precipitate diameter from 4.3 to 5.6 nm for both alloys.This research was supported by The Project Bridging The Gap, funded by the Erasmus Mundus External Cooperation Window Program. Acknowledgements also to the University of Minho, for the provision of research facilitie

    La erosión en campos cultivados en Galicia (NW España)

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    [Resumen] En la presente comunicación se realiza un seguimiento de la erosión en parcelas cultivadas en Galicia. Para ello, en la estación experimental El Pedroso se construyeron dos parcelas, de diferente pendiente, y se sometieron a un proceso de laboreo según las formas tradicionales de cultivar. En la presente comunicación se exponen los resultados del seguimiento de la experimentación desde abril a diciembre de 1995, en donde se observa que la pendiente desempeña una función distinta de la que en un principio podría pensarse, dado que la escorrentía y carga varían de forma inversa a la pendiente.[Abstract] A very closed study of erosion is made in this paper about plough plots in Galicia. For this, in the experimental station El Pedroso were built two plots, with different slope, and were ploughed in a traditional way. In this paper we resume the results of the experiment from april to december 1995, where it is seen that slope has a different function that was thought at the beginning of the experiment, because discharge and load don't vary directly with slope

    Chemical composition of corn and sorghum grains cultivated in Oxisol with different application methods and doses of zinc.

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    In general, tropical soils present low concentrations of zinc (Zn), and the deficiency of Zn is recognized as a world nutritional problem for cereal production and human beings. Therefore, the main goal of this study was to assess the effects of different methods of Zn application on the quality of corn and sorghum grains grown in Oxisol. Two experiments were set up in the experimental area of UNESP (campus of Jaboticabal, Brazil). The following nine treatments were applied:three doses of Zn by banded application (seed furrows), three doses of Zn by incorporation into soil (0-20 cm depth), foliar application, seed application, and control (no Zn applied). The treatments were arranged in randomized blocks with four replicates. The contents of Zn, carbohydrates and proteins were determined for corn and sorghum grains. Regardless of the method, Zn application promoted higher contents of this micronutrient in corn and sorghum grains. The banded application method of Zn in soil promoted greater contents of total carbohydrates, starch and protein in both cultures. The incorporation of Zn into the soil method provided higher contents of soluble carbohydrates in both corn and sorghum grains

    High spatial resolution optical imaging of the multiple T Tauri system LkH{\alpha} 262/LkH{\alpha} 263

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    We report high spatial resolution i' band imaging of the multiple T Tauri system LkHα\alpha 262/LkHα\alpha 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2 m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkHα\alpha 263 A and B (0.41 arcsec separation) and marginal evidence for an unresolved binary or a disc in LkHα\alpha 262. The AOLI data combined with previously available and newly obtained optical and infrared imaging show that the three components of LkHα\alpha 263 are co-moving, that there is orbital motion in the AB pair, and, remarkably, that LkHα\alpha 262-263 is a common proper motion system with less than 1 mas/yr relative motion. We argue that this is a likely five-component gravitationally bounded system. According to BT-settl models the mass of each of the five components is close to 0.4 M⊙_{\odot} and the age is in the range 1-2 Myr. The presence of discs in some of the components offers an interesting opportunity to investigate the formation and evolution of discs in the early stages of multiple very low-mass systems. In particular, we provide tentative evidence that the disc in 263C could be coplanar with the orbit of 263AB.Comment: 11 pages, 7 figures, Accepted 2016 May

    Influence of indirect ultrasonic vibration on the microstructure and mechanical behavior of Al-Si-Cu alloy

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    The influence of high intensity ultrasound (US) propagating through a steel mold on the microstructure and mechanical properties of die-cast AlSi9Cu3, for different levels of electric power and at different distances to the waveguide/mold interface. The influence of those parameters on the morphology of -Al and eutectic Si and on the volume of porosity were investigated and characterized. The morphological characterization revealed that the high intensity vibration not only promoted the formation of small -Al globular grains but also modify the eutectic silicon, as well as decreased the volume of porosity. Besides microstructure modification, US treatment improved the alloy mechanical properties, namely UTS and strain, which maximum values were 339 MPa and 2.9% respectively by comparison to the values obtained for castings produced without US vibration. A mechanism of eutectic Si modification based on theoretical-experimental analysis is proposedFCT - Fundação para a Ciência e Tecnologi

    Probing the Early Evolution of Young High-Mass Stars

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    Near-infrared imaging surveys of high-mass star-forming regions reveal an amazingly complex interplay between star formation and the environment (Churchwell et al. 2006; Alvarez et al. 2004). By means of near-IR spectroscopy the embedded massive young stars can be characterized and placed in the context of their birth site. However, so far spectroscopic surveys have been hopelessly incomplete, hampering any systematic study of these very young massive stars. New integral field instrumentation available at ESO has opened the possibility to take a huge step forward by obtaining a full spectral inventory of the youngest massive stellar populations in star-forming regions currently accessible. Simultaneously, the analysis of the extended emission allows the characterization of the environmental conditions. The Formation and Early Evolution of Massive Stars (FEMS) collaboration aims at setting up a large observing campaign to obtain a full census of the stellar content, ionized material, outflows and PDR's over a sample of regions that covers a large parameter space. Complementary radio, mm and infrared observations will be used for the characterization of the deeply embedded population. For the first eight regions we have obtained 40 hours of SINFONI observations. In this contribution, we present the first results on three regions that illustrate the potential of this strategy.Comment: To appear in ASP Conf. Proceedings of "Massive Star Formation: Observations confront Theory", H. Beuther et al. (eds.), held in Heidelberg, September 200
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