468 research outputs found

    Linking mould filling and structural simulations

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    Computer Aided Engineering (CAE) is common standard in the development process within the automotive industry. For thermoplastic components, for example, the manufacturing process is commonly simulated with injection moulding simulation software and passive safety with explicit crash software. Currently both disciplines are only linked within the simulation of fibre reinforced thermoplastics to take into account the fibre orientation from injection moulding simulation within crash simulation due to the significant influence of the fibre orientation on mechanical part properties. This work proposes a methodology that allows consideration of moulding conditions on the mechanical behaviour of unreinforced injection moulded components by coupling injection moulding simulation (Moldflow) and crash simulation (LS-DYNA (R)/RADIOSS (R)). A newly developed dedicated computer application allows to directly consider results from injection simulation within crash simulations. The manufacturing boundary conditions that most influence the mechanical behaviour are combined within the thermomechanical indices (TMI) methodology, and mapped onto each finite element within the crash simulation. Mathematical functions have been used to correlate the TMI to important mechanical properties of the moulded polymer. A user defined material model can read those indices and translate them to local mechanical properties.This work is funded by FEDER funds through the COMPETE 2020 program and National Funds through FCT under project UID/CTM/50025/2013, and grant SFRH/BD/51570/2011

    Exponential potentials and cosmological scaling solutions

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    We present a phase-plane analysis of cosmologies containing a barotropic fluid with equation of state pγ=(γ1)ργp_\gamma = (\gamma-1) \rho_\gamma, plus a scalar field ϕ\phi with an exponential potential Vexp(λκϕ)V \propto \exp(-\lambda \kappa \phi) where κ2=8πG\kappa^2 = 8\pi G. In addition to the well-known inflationary solutions for λ23γ\lambda^2 3\gamma in which the scalar field energy density tracks that of the barotropic fluid (which for example might be radiation or dust). We show that the scaling solutions are the unique late-time attractors whenever they exist. The fluid-dominated solutions, where V(ϕ)/ργ0V(\phi)/\rho_\gamma \to 0 at late times, are always unstable (except for the cosmological constant case γ=0\gamma = 0). The relative energy density of the fluid and scalar field depends on the steepness of the exponential potential, which is constrained by nucleosynthesis to λ2>20\lambda^2 > 20. We show that standard inflation models are unable to solve this `relic density' problem.Comment: 6 pages RevTeX file with four figures incorporated (uses RevTeX and epsf). Matches published versio

    Local and regional characterisation of the diurnal mountain wind systems in the Guadarrama mountain range (Spain)

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    Póster presentado en: EGU General Assembly celebrada del 23 al 28 de abril de 2017 en Viena, Austria.This research has been partially funded by the Spanish Government (MINECO projects CGL2015-65627-C3-3-R and CGL2012-37416-C04-02) and by the GR3/14 program (supported by UCM and Banco Santander) through the Research Group “Micrometeorology and Climate Variability” (No.910437)

    Thiophene- and carbazole-substituted N-Methyl-Fulleropyrrolidine acceptors in PffBT4T-2OD based solar cells

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    The impact of fullerene side chain functionalization with thiophene and carbazole groups on the device properties of bulk-heterojunction polymer:fullerene solar cells is discussed through a systematic investigation of material blends consisting of the conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2′;5′,2″;5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) as donor and C60 or C70 fulleropyrrolidines as acceptors. The photovoltaic performance clearly depended on the molecular structure of the fulleropyrrolidine substituents although no direct correlation with the surface morphology of the photoactive layer, as determined by atomic force microscopy, could be established. Although some fulleropyrrolidines possess favorable lowest unoccupied molecular orbital levels, when compared to the standard PC71BM, they originated OPV cells with inferior efficiencies than PC71BM-based reference cells. Fulleropyrrolidines based on C60 produced, in general, better devices than those based on C70, and we attribute this observation to the detrimental effect of the structural and energetic disorder that is present in the regioisomer mixtures of C70-based fullerenes, but absent in the C60-based fullerenes. These results provide new additional knowledge on the effect of the fullerene functionalization on the efficiency of organic solar cells.This work was financially supported by: Base Funding — UIDB/00511/2020 of the Laboratory forProcess Engineering, Environment, Biotechnology and Energy — LEPABE — funded by national funds through theFCT/MCTES (PIDDAC). This work was partially funded within the scope of the project i3N, UIDB/50025/2020 & UIDP/50025/2020, financed by national funds through the FCT/MEC. Thanks are also due to FCT/MEC for thefinancial support to QOPNA (FCT UID/QUI/00062/2019), CICECO-Aveiro Institute of Materials (UIDB/50011/2020& UIDP/50011/2020), CQE (FCT UIDB/00100/2020), and CIQUP (FCT UID/QUI/UI0081/2019) research units, throughnational funds and where applicable co-financed by the FEDER, within the PT2020 Partnership Agreement. H.G.thanks Fundação para a Ciência e a Tecnologia (FCT) for his PhD scholarship (SFRH/BD/103009/2014). The researchcontracts of F.F. (REF. -168-89-ARH/2018) is funded by national funds (OE), through FCT—Fundação para aCiência e Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of article 23,of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. M.M.F. acknowledges also supportfrom FCT under the project IF/00894/2015

    Hybrid model associating thermodynamic calculations and artificial neural network in order to predict molten steel temperature evolution from blowing end of a BOF for secondary metallurgy.

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    The developed model is an association of thermodynamic calculations for dissolution of alloys, slag formers and the deoxidation reaction in the molten steel with two artificial neural network (ANN) models trained with industrial data, to predict the molten steel temperature drop from the blowing end of the BOF until the first measurement at secondary metallurgy. To calculate the associated energy for deoxidation, an experiment was designed to set up the parameters for oxygen partitioning among deoxidants, with timed aluminum addition during teeming being the main parameter. The temperature control in the teeming stage presented a standard deviation for the error of prediction of 5.46 oC, for transportation from the rinsing station to the secondary metallurgy of 2.79 oC. The association of all calculations presented an error standard deviation of 7.49 oC. The operational validation presented superior accuracy compared with the current method for controlling the temperature, resulting in a reduction in the aluminum consumption for heating at secondary metallurgy with a potential economy of U$ 4.07 million per year for a steel shop producing 5 million tons of steel yearly. The artificial neural network model confirmed its capacity for modeling a complex multivariable process and the separation of thermodynamic calculation provides a better adaptability to different steel grades with different teeming strategies

    O Império Britânico. Ideologia, perspectivas, percepções

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    O núcleo de investigadores dedicado aos estudos de cultura do Centro de Estudos Anglísticos da Universidade de Lisboa empenhou boa parte da sua actividade, no ano de 2008-2009, na preparação de duas jornadas temáticas sobre o Império Britânico. Para a escolha deste objecto de investigação convergiram os interesses individuais dos investigadores, mobilizados para o estudo sistemático de conceitos como império e imperialismo, colónia e colonialismo, de ideologias como o liberalismo, ou para o estudo de representações de identidade. Com o intuito comum de examinar criticamente uma multiplicidade de discursos sobre o Império Britânico, as comunicações que agora são publicadas sustentam diferentes possibilidades de aproximação metodológica aos estudos de cultura e posicionam o diálogo entre elas como instrumento de desenvolvimento do conhecimento em torno de um mesmo objecto. O Império Britânico é, assim, interpelado na sua origem enquanto portador de uma “missão civilizadora” e são examinados discursos de supremacia europeia crescentemente desconstruídos pelas novas linhas de análise cultural, sensíveis estas à dissonância, à dúvida, ao silêncio e ao “não dito” das culturas em presença. O confronto e o conflito entre a cultura dominante e as culturas subordinadas, a construção de novas identidades, a instabilidade dos sujeitos foram, nestas jornadas, objecto de apresentações inovadoras em suportes visuais, como a pintura, a fotografia ou o filme.Fundação para a Ciência e a Tecnologi

    Locke's legacy

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    A organização de um colóquio em torno da “herança de Locke” foi uma ideia que nasceu no Centro de Estudos Anglísticos da Universidade de Lisboa, no âmbito do núcleo de investigação dedicado aos estudos de cultura inglesa. Vários textos de Locke são regularmente incluídos nos programas de graduação e de pósgraduação em Estudos Anglísticos, além de objecto de estudo especializado no Centro de Estudos Anglísticos. Assim, fazia todo o sentido comemorar, no ano de 2004, a passagem de mais um centenário sobre a morte de Locke, e celebrar a vitalidade da sua obra ao longo de três séculos reunindo especialistas que, publicamente, apresentassem e discutissem aspectos dessa obra que continuam activos no presente. O volume que agora se publica reúne as comunicações apresentadas em Janeiro de 2004. A variedade dos temas abordados e a manifesta relevância de que se revestem para o estudo da modernidade demonstram que a herança de Locke continua a produzir riqueza, e que constitui património cultural a ser herdado por novas gerações.Fundação para a Ciência e a Tecnologi

    Molecular profiling of a rare rosette-forming glioneuronal tumor arising in the spinal cord

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    Rosette-forming glioneuronal tumor (RGNT) of the IV ventricle is a rare and recently recognized brain tumor entity. It is histologically composed by two distinct features: a glial component, resembling pilocytic astrocytoma, and a component forming neurocytic rosettes and/or perivascular rosettes. Herein, we describe a 33-year-old man with RGNT arising in the spinal cord. Following an immunohistochemistry validation, we further performed an extensive genomic analysis, using array-CGH (aCGH), whole exome and cancer-related hotspot sequencing, in order to better understand its underlying biology. We observed the loss of 1p and gain of 1q, as well as gain of the whole chromosomes 7, 9 and 16. Local amplifications in 9q34.2 and 19p13.3 (encompassing the gene SBNO2) were identified. Moreover, we observed focal gains/losses in several chromosomes. Additionally, on chromosome 7, we identified the presence of the KIAA1549:BRAF gene fusion, which was further validated by RT-PCR and FISH. Across all mutational analyses, we detected and validated the somatic mutations of the genes MLL2, CNNM3, PCDHGC4 and SCN1A. Our comprehensive molecular profiling of this RGNT suggests that MAPK pathway and methylome changes, driven by KIAA1549:BRAF fusion and MLL2 mutation, respectively, could be associated with the development of this rare tumor entity.Conselho Nacional de Desenvolvimento Científico e Tecnológico [475358/2011-2] to RMR (www.cnpq.br); Fundação de Amparo a Pesquisa do Estado de São Paulo [2012/19590-0] to RMR and [2011/08523-7 and 2012/08287-4] to LTB (www.fapesp.br); the Foundation for Science and Technology (FCT) [PTDC/SAU-ONC/115513/2009] to RMR; and the National Cancer Institute [P30CA046934] to MG
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