2,465 research outputs found

    Exploring dynamic lighting, colour and form with smart textiles

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    This paper addresses an ongoing research, aiming at the development of smart textiles that transform the incident light that passes through them – light transmittance – to design dynamic light without acting upon the light source. A colour and shape change prototype was developed with the objective of studying textile changes in time; to explore temperature as a dynamic variable through electrical activation of the smart materials and conductive threads integrated in the textile substrate; and to analyse the relation between textile chromic and morphologic behaviour in interaction with light. Based on the experiments conducted, results have highlighted some considerations of the dynamic parameters involved in the behaviour of thermo-responsive textiles and demonstrated design possibilities to create interactive lighting scenarios.This work is supported by FEDER funds through the Operational Programme for Competitiveness Factors – COMPETE and National Funds through FCT – Foundation for Science and Technology within the scope of the projects SFRH/BD/87196/2012, POCI-01-0145-FEDER-007136 and UID/CTM/00264. The authors also like to acknowledge Smart Textiles Design Lab for the support on the prototype development.info:eu-repo/semantics/publishedVersio

    Vacuum Polarization by a Magnetic Flux Tube at Finite Temperature in the Cosmic String Spacetime

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    In this paper we analyse the effect produced by the temperature in the vacuum polarization associated with charged massless scalar field in the presence of magnetic flux tube in the cosmic string spacetime. Three different configurations of magnetic fields are taken into account: (i)(i) a homogeneous field inside the tube, (ii)(ii) a field proportional to 1/r1/r and (iii)(iii) a cylindrical shell with δ\delta-function. In these three cases, the axis of the infinitely long tube of radius RR coincides with the cosmic string. Because the complexity of this analysis in the region inside the tube, we consider the thermal effect in the region outside. In order to develop this analysis, we construct the thermal Green function associated with this system for the three above mentioned situations considering points in the region outside the tube. We explicitly calculate in the high-temperature limit, the thermal average of the field square and the energy-momentum tensor.Comment: 16 pages, 1 figur

    Otimização do processo de descascamento de soja utilizando descascador de discos paralelos horizontais.

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    bitstream/item/67908/1/CT-43-.pd

    Manual de produção artesanal de soja frita.

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    Introdução. Definição de soja frita (soynuts). Fluxograma de produção. Descrição do processo. Embalagem. Referências bibliográficas.bitstream/item/78987/1/doc66-2005.pd

    A semiquantitative approach to the impurity-band-related transport properties of GaMnAs nanolayers

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    We investigate the spin-polarized transport of GaMnAs nanolayers in which a ferromagnetic order exists below a certain transition temperature. Our calculation for the self-averaged resistivity takes into account the existence of an impurity band determining the extended ("metallic" transport) or localized (hopping by thermal excitation) nature of the states at and near the Fermi level. Magnetic order and resistivity are inter-related due to the influence of the spin polarization of the impurity band and the effect of the Zeeman splitting on the mobility edge. We obtain, for a given range of Mn concentration and carrier density, a "metallic" behavior in which the transport by extended carriers dominates at low temperature, and is dominated by the thermally excited localized carriers near and above the transition temperature. This gives rise to a conspicuous hump of the resistivity which has been experimentally observed and brings light onto the relationship between transport and magnetic properties of this material

    Contributions for innovative institutional research quality assessment practices and processes

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    The urge for the achievement of excellence patterns in research has led higher education institutions to become more and more aware of their role in the process by putting their strategic emphasis on the development of assessment tools towards the monitoring and evaluation of research quality. We intend to review the lessons learned from current research assessment experiences and collect good practices and recommendations using semi-directed interviews with evaluation panel members, institutions’ representatives and researchers involved in the last UK’s Research Assessment Exercise. Our major aim is to present and discuss a set of guidelines as a first input for the design of an evaluation framework to evaluate and monitor the quality of research at an institutional level. We seek to add significantly to our understanding of what can be actually done using strategic planning to look forward in the areas of research engagement/resources and institutional culture, productivity/ performance and innovation, quality/merit and impact and sustainability/ support. Overall, the challenges of promoting research are discussed and strategies for its enhancement are included

    On the nature of the spin-polarized hole states in a quasi-two-dimensional GaMnAs ferromagnetic layer

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    A self-consistent calculation of the density of states and the spectral density function is performed in a two-dimensional spin-polarized hole system based on a multiple-scattering approximation. Using parameters corresponding to GaMnAs thin layers, a wide range of Mn concentrations and hole densities have been explored to understand the nature, localized or extended, of the spin-polarized holes at the Fermi level for several values of the average magnetization of the Mn ystem. We show that, for a certain interval of Mn and hole densities, an increase on the magnetic order of the Mn ions come together with a change of the nature of the states at the Fermi level. This fact provides a delocalization of spin-polarized extended states anti-aligned to the average Mn magnetization, and a higher spin-polarization of the hole gas. These results are consistent with the occurrence of ferromagnetism with relatively high transition temperatures observed in some thin film samples and multilayered structures of this material.Comment: 3 page

    Exotic looped trajectories via quantum marking

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    We provide an analytical and theoretical study of exotic looped trajectories (ELTs) in a double-slit interferometer with quantum marking. We use an excited Rydberg-like atom and which-way detectors such as superconducting cavities, just as in the Scully-Englert-Walther interferometer. We indicate appropriate conditions on the atomic beam or superconducting cavities so that we determine an interference pattern and fringe visibility exclusive from the ELTs. We quantitatively describe our results for Rubidium atoms and propose this framework as an alternative scheme to the double-slit experiment modified to interfere only these exotic trajectories.Comment: 10 pages, 5 figure
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