2,518 research outputs found

    Decomposition of stochastic flows with automorphism of subbundles component

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    We show that given a GG-structure PP on a differentiable manifold MM, if the group G(M)G(M) of automorphisms of PP is big enough, then there exists the quotient of an stochastic flows phitphi_t by G(M)G(M), in the sense that ϕt=ξtρt\phi_t = \xi_t \circ \rho_t where ξtG(M)\xi_t \in G(M), the remainder ρt\rho_t has derivative which is vertical but transversal to the fibre of PP. This geometrical context generalizes previous results where MM is a Riemannian manifold and ϕt\phi_t is decomposed with an isometric component, see Liao \cite{Liao1} and Ruffino \cite{Ruffino}, which in our context corresponds to the particular case of an SO(n)-structure on MM.Comment: To appear in Stochastics and Dynamics, 201

    From rapid prototyping to building in real scale: methodologies for upscaling additive manufacturing in architecture

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    The manufacture of architectural components mediated by computer-controlled Additive Manufacturing (AM) technologies has highlighted several positive aspects of their application, namely by enabling customised design solutions and high-performance complex geometries. Taking into account the experience of the Advanced Ceramics R&D Lab, in the production of small- / medium- scale prototypes, this paper explores the main variables and constraints of the production of real-scale architectural components. This information points to a set of procedures that should be avoided and others that should be privileged, allowing to anticipate how AM can contribute for the achievement of high performance components on a large scale.This work has the financial support of the Project Lab2PT – Landscapes, Heritage and Territory laboratory – AUR/04509 and FCT through national founds and when applicable of the FEDER cofinancing, in the aim of the new partnership agreement PT2020 and COMPETE2020 – POCI 01 0145FEDER 007528

    Predictive Optimal Matrix Converter Control for a Dynamic Voltage Restorer with Flywheel Energy Storage

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    This paper presents a predictive optimal matrix converter controller for a flywheel energy storage system used as Dynamic Voltage Restorer (DVR). The flywheel energy storage device is based on a steel seamless tube mounted as a vertical axis flywheel to store kinetic energy. The motor/generator is a Permanent Magnet Synchronous Machine driven by the AC-AC Matrix Converter. The matrix control method uses a discrete-time model of the converter system to predict the expected values of the input and output currents for all the 27 possible vectors generated by the matrix converter. An optimal controller minimizes control errors using a weighted cost functional. The flywheel and control process was tested as a DVR to mitigate voltage sags and swells. Simulation results show that the DVR is able to compensate the critical load voltage without delays, voltage undershoots or overshoots, overcoming the input/output coupling of matrix converters

    Idade, origem e protólitos de granitos variscos de três áreas portuguesas

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    Publicação digital - Online em 5 Fev. 201

    Immobilization of proteases with a water soluble–insoluble reversible polymer for treatment of wool

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    A commercial protease, Esperase, was covalently linked to Eudragit S-100, a reversible soluble–insoluble polymer by carbodiimide coupling. When compared to the native enzyme, the immobilized form presented a lower specific activity towards high molecular weight substrates but a higher thermal stability at all temperatures tested. The optimum pH of the immobilized protease was shifted towards the alkaline side by about one pH unit while there was no change in optimum temperature between the free and immobilized protease. The immobilized protease exhibited a good storage stability and re-usability. Enzymatic treatment of wool using proteases has been investigated for wool shrink-resist finishing. It was found that using the immobilized protease in the enzymatic treatment of wool there was a reduction of weight and fibre tensile strength loss because the proteolytic attack is only limited to the cuticle surfaces of wool fibres. This novel approach is a promising alternative for wool shrink-resist finishing to replace the conventional chlorine treatments. This environmentally friendly bioprocess needs to be further characterized to a complete understanding and optimization

    A cone-continuity constraint qualification and algorithmic consequences

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    PRONEX - PROGRAMA DE APOIO A NÚCLEOS DE EXCELÊNCIAFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOREvery local minimizer of a smooth constrained optimization problem satisfies the sequential approximate Karush-Kuhn-Tucker (AKKT) condition. This optimality condition is used to define the stopping criteria of many practical nonlinear programming algorithms. It is natural to ask for conditions on the constraints under which AKKT implies KKT. These conditions will be called strict constraint qualifications (SCQs). In this paper we define a cone-continuity property (CCP) that will be shown to be the weakest possible SCQ. Its relation to other constraint qualifications will also be clarified. In particular, it will be proved that CCP is strictly weaker than the constant positive generator constraint qualification.Every local minimizer of a smooth constrained optimization problem satisfies the sequential approximate Karush-Kuhn-Tucker (AKKT) condition. This optimality condition is used to define the stopping criteria of many practical nonlinear programming algorithms. It is natural to ask for conditions on the constraints under which AKKT implies KKT. These conditions will be called strict constraint qualifications (SCQs). In this paper we define a cone-continuity property (CCP) that will be shown to be the weakest possible SCQ. Its relation to other constraint qualifications will also be clarified. In particular, it will be proved that CCP is strictly weaker than the constant positive generator constraint qualification26196110PRONEX - PROGRAMA DE APOIO A NÚCLEOS DE EXCELÊNCIAFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORPRONEX - PROGRAMA DE APOIO A NÚCLEOS DE EXCELÊNCIAFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORE-26/111.449/2010-APQ12013/07375-0; 2012/20339-0; 2013/05475-7304618/2013-6; 482549/2013-0; 303750/2014-6; 303013/2013-3sem informaçã
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