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Biblioteca Digital do IPB (53.442 recursos)

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DEMAT - Publicações Não Indexadas em Actas/Proceedings

Mostrando recursos 1 - 20 de 57

  1. In-service teacher training in Portugal: objectives, organization and impact on teacher's career

    Ferreira, Olga; Pereira, Ana I.; Silva, A.; Afonso, E.; Barreiro, M.F.
    This paper presents a short overview of teacher´s training as considered by the Portuguese legislation: (i) initial teacher education (ITE), (ii) specialized training and (iii) in-service teacher training. A particular emphasis will be given to in-service teacher training. Nowadays, ITE corresponds to level 7 of the European Qualifications Framework (master degree). It is a career-long professional development, where research-based and in context practice are important features. Specialized training is intended to provide qualification in complementary educational functions, such as special education, school administration and inspection activities, socio-cultural animation and basic education for adults. In-service training or continuous training allows teachers...

  2. Lithium depletion in the sun

    Morel, P.; Provost, J.; Berthomieu, G; Matias, José; Zahn, J.P.
    Physical properties of non-standard solar models including pre-main sequence phase, penetrative convention and microscopic diffusion are presented.We emphasize on 7Li depletion.

  3. Recent results of H-mode studies on asdex

    Wagner, F.; Field, A.R.; Fussmann, G.; Hofmann, J.V.; Manso, M.E.; Vollmer, O.; Matias, José
    In a comparative study of various confinement regimes the H-mode demonstrated the best performance. Confinement enhancement factors (above ITER 89-P L-mode scaling) in the range of 1.6 fH 2.8 have been achieved with values depending on the divertor configuration, the wall condition, ELM behaviour and the plasma ion spicies. Long-pulse H-phases, withELMs, of up to 3.5s with constant confinement time, recycling and impurity characteristics are archived. H* -mode operation is possible without a loss of current scaling at qa values as low as 2.2. The B-limit is the same with and without ELMs. Murakami parameters are similar in H-and L-modes.

  4. Experimental determination of the transient transport and of fluctuations relevant to transport in ASDEX

    Niedermeyer, H.; Dodel, G.; Hendler, M.; Fussmann, G.; Gehre, O.; Gentile, K.W.; Giannone, L.; Holzhauer, E.; Krieger, K.; Rudyj, A.; Theimer, G.; Bengtson, R.D.; Carlson, A.; Eberhagen, A.; Engelhardt, W.; Gernhardt, J.; Gruber, O.; Hofmann, J.V.; Karger, F.; Kluber, O.; Kramer, M; Manso, M.E.; Matias, José
    Particle transport was studied in ASDEZ with modulated puffing of the discharge gas and of impurities. The energy transport is investigated by numerical simulation of the heat pulse after the swatooth crash. Small scale density fluctuations are investigated in the confinement region with far infrared scattering and reflectometry and in the edge plasma with langmuir probes and Ha diagnostic. In addition to a diffuse component of the particle transport, a strong inward drift is observed in all discharges. In ohmic discharges the transport coefficients decrease and saturate like 1/TE with increasing density. They are smaller in deuterium that in hydrogen....

  5. Reflectometry measurements of the m=1 satellite mode in L- and H-mode plamas in ASDEX

    Serra, F.; Manso, M.E.; Silva, A.; Matias, José; Wagner, F.; Zohm, H.; Kallenbach, A.; Varela, P.
    In ASDEX, with strong NB, heating, often a large central m=1, n=1 mode is observed on the SXR emission. For PNBI > 1 MW a mode rotating with the same frequency, the so-called`m=1 satellite`, is seen on the magnetic pick-up coils in the L and H-phases. Magnetic measurement s in the divertor chamber suggest that the satellite mode might be located outside the separatix, on open field lines reaching the diretor /1/. Here we present results from localized microave reflectrometric measurements. The time evolution of the satellite mode frequency is studied for plasmas with different qa and the mode localization...

  6. Stopping rules effect on a derivative-free filter multistart algorithm for multilocal programming

    Fernandes, Florbela P.; Costa, M.F.P.; Fernandes, Edite M.G.P.
    Multilocal programming aims to identify all the local solutions of constrained optimization problems. The purpose of this paper is to analyze the effect of stopping rules on the performance of a particular multistart method, which relies on a derivative-free local search procedure to converge to a solution, when solving multilocal optimization problems. The method herein presented implements the approximate descent direction method combined with a filter methodology to handle the constraints by forcing the local search towards the feasible region. Two stopping rules are tested on five classical multimodal problems.

  7. Cell-free layer measurements in a bifurcation microchannel : comparison between a manual and automatic methods

    Bento, David; Pinho, Diana; Pinto, Elmano; Yaginuma, Tomoko; Correia, Teresa Montenegro; Lima, José; Pereira, Ana I.; Fernandes, Carla S.; Dias, Ricardo P.; Lima, R.
    O artigo deve também estar associado ao Departamento de Electrotécnia, Tecnologia Mecânica e Química

  8. Desenvolvimento de um microdispositivo biomédico para a separação de células sanguíneas

    Novais, Susana; Pinho, Diana; Pereira, Ana I.; Mujika, Maite; Arana, Sergio; Lima, R.
    Neste trabalho procedeu-se ao desenho e implantação de um dispositivo biomédico, com capacidade de realizar a separação das células sanguíneas da camada de plasma. Numa primeira fase do trabalho realizou-se o desenho e fabricação do dispositivo, através da técnica de litografia suave. A segunda fase consistiu no estudo do escoamento sanguíneo com o objetivo de analisar o efeito das constrições na variação da espessura camada de plasma. Concluímos que a constrição proporciona um aumento da espessura da camada de plasma e à medida que se aumenta o hematócrito a camada de plasma tende a diminuir.

  9. Graphical simulator of mathematical algorithms (GraSMA)

    Balsa, Carlos; Alves, Luís M.; Pereira, Maria João; Rodrigues, Pedro João
    Our goal is to develop an interactive software GraSMA that illustrates the execution of mathematical algorithms in the context of numerical methods. We want to create a working tool for teachers and learning tool for students. To achieve it we only use free software (as it is the Open Source software). The strategy followed was to extend the original algorithm code, implemented in Octave, with inspector instructions, recording in a XML (eXtensible Markup Language) file everything that happened during the execution. Subsequently, the XML file is parsed by a Java application that graphically represents the mathematic objects and their behaviour during execution. In this paper,...

  10. Flow of red blood cells through microchannel with a confluence

    Vladimir, Leble; Lima, R.; Fernandes, Carla S.; Dias, Ricardo P.
    Over the years micro-visualization techniques have been used to investigate in vitro blood flow through straight microchannels with dimensions close to in vivo capillaries. However, a few detailed studies have been performed in complex in vitro microvascular networks composed by diverging and converging bifurcations. The main purpose of present work is to show the application of a confocal micro-PTV system to track both flourescent particles and red blood cells (RBCs) through a rectangular polydimethysiloxane (PDMS) microchannel with a confluence. The measurements of the flow behaviour of trace particles suspended in pure water and RBCs in concentrated suspensions were performed in...

  11. Motions of trace particles and red blood cells in a PDMS microchannel with a converging bifurcation

    Leble, Vladimir; Dias, Ricardo P.; Lima, R.; Fernandes, Carla S.; Ishikawa, Takuji; Imai, Yohsuke; Yamaguchi, Takami
    This paper presents microflow visualizations of both pure water and red blood cells (RBCs) in a converging bifurcation. The visualizations are a combination of results obtained from a confocal micro-PTV system and an image analysis technique known as “Zproject” from ImageJ. Our preliminary qualitative results suggest that the cell-free layer that is formed in middle of the microchannel (after confluence apex) may play an important role on RBCs trajectories.

  12. An hybrid approach for the parallelization of a block iterative algorithm

    Balsa, Carlos; Guivarch, Ronan; Ruiz, Daniel; Zenadi, Mohamed
    The Cimmino method is a row projection method in which the original linear system is divided into subsystems. At every iteration, it computes one projection per subsystem and uses these projections to construct an approximation to the solution of the linear system. The usual parallelization strategy in block algorithms is to distribute the different blocks on the available processors. In this paper, we follow another approach where we do not perform explicitly this block distribution to processors within the code, but let the multi-frontal sparse solver MUMPS handle the data distribution and parallelism. The data coming from the subsystems defined...

  13. MUMPS based approach to parallelize the block cimmino algorithm

    Balsa, Carlos; Guivarch, Ronan; Raimundo, João; Ruiz, Daniel
    The Cimmino method is a row projection method in which the original linear system is divided into subsystems. At every iteration, it computes one projection per subsystem and uses these projections to construct an approximation to the solution of the linear system. The usual parallelization strategy applied in block algorithms is to distribute the different blocks on the different available processors. In this paper, we follow another approach where we do not perform explicitely this block distribution to processors whithin the code, but let the multi-frontal sparse solver MUMPS handle the data distribution and parallelism. The data coming from the...

  14. Teaching methodologies and open source software: empirical application to econometrics and mathematics

    Nunes, Alcina; Balsa, Carlos
    Em co-autoria com Alcina Nunes do Departamento de Economia e Gestão.

  15. Numerical prediction of velocity, pressure and shear rate distributions in stenosed channels

    Fernandes, Carla S.; Dias, Ricardo P.; Lima, R.
    Wall shear rates and pressure developed in circulatory system play an important role on the development of some clinical problems such as atherosclerosis and thrombosis. In the present work, blood flow behaviour was numerically studied in simplified domains and several relevant local properties were determined. The stenosis degree was varied in the distinct studied channels and blood rheology was described by three different models – constant viscosity, power-law model and Carreau model. Pressure attains maximum values in the wall of the atheroma and shear rates achieved maximum values in the top of the atheroma. It was also observed that, with...

  16. Particle swarm and simulated annealing for multi-global optimization

    Vaz, Ismael; Pereira, Ana I.; Fernandes, Edite M.G.P.
    Particle swarm and simulated annealing optimization algorithms proved to be valid in finding a global optimum in the bound constrained optimization context. However, their original versions can only detect one global optimum even if the problem has more than one solution. In this paper we propose modifications to both algorithms. In the particle swarm optimization algorithm we introduce gradient information to enable the computation of all the global and local optima. The simulated annealing algorithm is combined with a stretching technique to be able to compute all global optima. The numerical experiments carried out with a set of well-known test...

  17. Assessment of a hybrid approach for nonconvex constrained MINLP problems

    Fernandes, Florbela P.; Costa, M. Fernanda; Fernandes, Edite M.G.P.
    A methodology to solve nonconvex constrained mixed-integer nonlinear programming (MINLP) problems is presented. A MINLP problem is one where some of the variables must have only integer values. Since in most applications of the industrial processes, some problem variables are restricted to take discrete values only, there are real practical problems that are modeled as nonconvex constrained MINLP problems. An efficient deterministic method for solving nonconvex constrained MINLP may be obtained by using a clever extension of Branch-and-Bound (B&B) method. When solving the relaxed nonconvex nonlinear programming subproblems that arise in the nodes of a tree in a B&B algorithm, using local search methods, only convergence to local optimal...

  18. Desempenho hidráulico de canais sinusoidais durante o fluxo laminar de fluidos não-Newtonianos

    Fernandes, Carla S.; Dias, Ricardo P.; Pinheiro, Jorge Vagaroso de Barros
    Neste trabalho estudou-se numericamente o escoamento isotérmico laminar completamente desenvolvido de fluidos Newtonianos e não-Newtonianos em canais de permutadores de calor de placas do tipo chevron com ângulo de corrugação igual a zero (canais do tipo sinusoidal). Este estudo foi efectuado recorrendo ao software de dinâmica de fluidos computacional, baseado no método de elementos finitos, POLYFLOW®. Para cada uma das geometrias estudadas (com valores de razão de aspecto de canal entre 0 e 1), estudaram-se os factores de fricção de Fanning, f, tendo sido determinadas, para cada um dos canais, curvas de fricção únicas (f Reg = K) para os...

  19. Tilings and Anosov diffeomorphisms

    Almeida, João Paulo; Pinto, Alberto A.
    A. Pinto and D. Sullivan [4] proved a one-to-one correspondence between: (i) C1+ conjugacy classes of expanding circle maps; (ii) solenoid functions and (iii) Pinto-Sullivan’s dyadic tilings on the real line. A. Pinto [1,3] introduced the notion of golden tilings and proved a one-to-one correspondence between (i) smooth conjugacy classes of Anosov diffeomorphisms, with an invariant measure absolutely continuous with respect to the Lebesgue measure, that are topologically conjugate to the linear automorphism G(x; y) = (x + y; x), (ii) affine classes of golden tilings and (iii) solenoid functions. Here we extend this last result and we exhibit a natural one-to-one correspondence between (i) smooth conjugacy classes of...

  20. Linear programming knowledge in first stage higher education courses

    Barros, Paula Maria; Pereira, Ana I.; Teixeira, Ana P.
    In this work we will describe an experimental study with approximately fifty Portuguese students of the 2nd year of the BSc Degree of Biomedical Engineering as well as Chemical and Biological Engineering Higher Education Courses. The aims of this study are to identify which knowledge of Linear Programming (LP) taught in High School the students acquired and still remember, which tools they used in that stage of education when learning the theme of LP and their opinion about the significance of LP in daily life problem resolution. We also propose to investigate if the students are able to use WinQSB software to solve LP problems. In addition, we...

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