Browsing by Issue Date, starting with "1998"
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- Kiss of our agony thou gatherest: O sacrifício em The Bridge, de Hart CranePublication . Mancelos, João deO sacrifício e o ritual de passagem marcam presença em vários poemas da obra The Bridge (1930), a mais ambiciosa do escritor modernista norte-americano Hart Crane (1899-1932). Neste artigo, recorro às perspetivas literária e mítica para examinar os textos “The River”, “Cape Hatteras” e “The Tunnel”. Abordo-os com o objetivo de estudar a tensa dialética entre passado e presente, espiritualidade e materialismo, fé e tecnologia, liberdade e capitalismo. Pretendo, assim, evidenciar o desejo que Crane tinha de erguer uma nova América, mítica e digna de ser poetada. Para tanto, recorro à minha opinião, a especialistas na obra de Hart Crane, com destaque para Paul Giles, Vincent Quinn e Jack Wolf, e a diversos mitólogos.
- A general correlation for the local loss coefficient in newtonian axisymmetric sudden expansionsPublication . Oliveira, Paulo J.; Pinho, Fernando; Schulte, A.Results from numerical simulations and guidance from an approximated corrected-theory, developed by Oliveira and Pinho (1997), have been used to arrive at a correlation expressing the irreversible loss coefficient for laminar Newtonian flow in axisymmetric sudden expansions. The correlation is valid for the ranges 1.5 < D2/D1 < 4 and 0.5 < Re < 200 with errors of less than 5%, except for 25 < Re < 100 where the error could be as much as 7%. The recirculation bubble length is also presented for the same range of conditions and the pressure recovery coefficient was calculated for Reynolds numbers above 15.
- Modernismo e antropologia: Para um casamento intercurricularPublication . Mancelos, João deNesta comunicação, analiso as relações profundas entre mito e palavra, aqui entendida como o nome que evoca um deus, um termo com força mágica ou, em geral, a poesia. A palavra procura a intemporalidade, a síntese do passado, presente e futuro, a supra-história. Procuro ver como este fenómeno interessou vários poetas modernistas, com destaque para Hart Crane (1899-1932), um dos mais singulares da sua geração. Para tanto, recorro a diversos mitólogos e a especialistas na obra de Crane.
- Numerical Simulation of Non-linear Elastic Flows with a General Collocated Finite-Volume MethodPublication . Oliveira, Paulo J.; Pinho, Fernando; Pinto. G. A.This paper reports the development and application of a finite-volume based methodology for the calculation of the flow of fluids which follow differential viscoelastic constitutive models. The novelty of the method lies on the use of the non-staggered grid arrangement, in which all dependent variables are located at the center of the control volumes, thus greatly simplifying the adoption of general curvilinear coordinates. The pressure–velocity–stress decoupling was removed by the development of a new interpolation technique inspired on that of Rhie and Chow, AIAA J 82 (1982) 998. The differencing schemes are second order accurate and the resulting algebraic equations for each variable are solved in a segregated way (decoupled scheme). The numerical formulation especially designed for the interpolation of the stress field was found to work well and is shown to be indispensable for accurate results. Calculations have been carried out for two problems: the entry flow problem of Eggleton et al., J. Non-Newtonian Fluid Mech. 64 (1996) 269, with orthogonal and non-orthogonal meshes; and the bounded and unbounded flows around a circular cylinder. The results of the simulations compare favourably with those in the literature and iterative convergence has been attained for Deborah and Reynolds numbers similar to, or higher than, those reported for identical flow problems using other numerical methods. The application of the method with non-orthogonal coordinates is demonstrated. The entry flow problem is studied in more detail and for this case differences between Newtonian and viscoelastic fluids are identified and discussed. Viscoelasticity is shown to be responsible for the development of very intense normal stresses, which are tensile in the wall region. As a consequence, the viscoelastic fluid is more intensely decelerated in the wall region than the Newtonian fluid, thus reducing locally the shear rates and the role of viscosity in redeveloping the flow. A layer of high stress-gradients is formed at the wall leading edge and is convected below and away from the wall; its effect is to intensify the aforementioned deviation of elastic fluid from the wall.
- A informação como utopiaPublication . Serra, PauloO problema da informação - a informação como problema - não é de hoje. Tal problema remonta, pelo menos, a Platão que, no Fedro, citando um velho mito egípcio, alerta para o perigo de, com a escrita, a mera informação (considerada, pelo filósofo, como “uma aparência de sabedoria”) ir, progressivamente, substituindo a educação (sem a qual não pode existir “a sabedoria em si mesma”). [...]
- A qualitative assessment of the role of a viscosity depending on the third invariant of the rate-of-deformation tensor upon turbulent non-Newtonian flowPublication . Oliveira, Paulo J.; Pinho, FernandoThe numerical simulation of some non-Newtonian effects in wall and wall-free turbulent flows, such as drag reduction in pipe flows or the decrease in transverse normal Reynolds stresses, has been attempted in the past with a limited degree of success on the basis of modified wall functions applied to traditional turbulence models (k–epsilon), rather than through more realistic rheological constitutive equations. In this work, it is qualitatively shown that if the viscosity function of a generalised Newtonian fluid is assumed to depend on the third invariant of the rate of deformation tensor, there is an increase of the viscous diffusion terms, but especially, of the dissipation of turbulence kinetic energy by a factor equal to the Trouton ratio of the fluid, divided by the Trouton ratio of the solvent, thus indicating a possible way to improve rheological–turbulence modelling.
- University-Industry-Government Relations: Some reflections on methodological and policy issues in the context of less favoured regionsPublication . Couto, Alcino PintoSince the beginning of the eighties we are witnessing a broad recognition amongst economists and policy makers of the importance of knowledge accumulation for the economic growth. This context explains the reinforcement of knowledge, technology and innovation centrality in the researchers agenda as well as in the design of the economic policy. As a result of the previous trends we need to consider two fundamental aspects from the viewpoint of regional and local development. First, the knowledge, technology and innovation play an important role on the performance of regional and local economy. Second, this means that the innovative activities emerge as a crucial vector of the process of convergence and inter-regional cohesion. In this case, we think that the contextual conditions of less favoured regions involve a reconfiguration of the methods of evaluating the innovative potential and analysing the role of the components of institutional structure, the working of that composite and varied set of actors involved in the different stages of the innovation and diffusion process. More attention should be drawn to the evaluation methodologies of the innovative process and its potential, the strategic role of university (missions, teaching activities, research activities, new organisational forms, the relations between the organisation of the university and its environment, ...) and to the design of the public policy ( financial support, demand-side policy, support to technological development and technological advice and guidance of local firms, regionalisation of technological policy, ...).
- Gender and the sexes in the Indonesian ArchipelagoPublication . Schouten, Maria Johanna ChristinaReview of book discussing gender in various regions of the Southeast Asian culture area
- Traffic from Mobility in Mobile Broadband SystemsPublication . Velez, Fernando J.; Correia, Luis M.Models allowing the study of the influence of coveragedistance and velocity on the supported traffic and on thenew calls traffic linear density are examined, and resultsare obtained for typical scenarios in a Mobile BroadbandSystem (MBS) with a linear coverage geometry. For systemswithout guard channels for handover, for a fixed boundingvalue for the blocking probability, the new calls traffic lin-ear density was analyzed, increasing with the decrease of themaximum coverage distance, R, being upper limited by avalue which depends on the characteristics of the mobilityscenario. However, call-dropping probability requirementsalso need to be fulfilled, leading to a new calls traffic densitythat only increases with the decrease of R down to an opti-mum value of R, and being lower for scenarios with highermobility. These optimum values of R are higher for scenar-ios with higher and higher mobility, leading to limitations insystem capacity, mainly for high mobility scenarios. Inorder to resolve these limitations, the use of guard channelsfor handover is studied, particularly for high mobilityscenarios. For these scenarios one concludes that there is adegradation in system capacity because, for the typicalcoverage distances foreseen for MBS, the new calls trafficlinear density is one order of magnitude below the valuesobtained for the pedestrian scenario (where it is approxi-mately 15 Erlang/km), decreasing from 2.47 Erlang/km, inthe urban scenario, down to 0.84 Erlang/km, in the highwayscenario, when two guard channels are used.
- Gender and the sexes in the Indonesian ArchipelagoPublication . Schouten, Maria Johanna ChristinaReview of collection of studies regarding gender in several regions of Southeast Asia. The articles in this volume, first presented as papers at a conference of the Association for South-East Asian Studies in the United Kingdom, add to the literature on gender in Southeast Asia. Although that literature may seem extensive by now, this publication is certainly not repetitive or redundant. On the contrary, besides presenting awealth of data, it attests to how useful and refreshing an approach which focuses on gender and gender relations can be, even when examining seemingly well-known facts.
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