2,082 research outputs found
An optimal order interior penalty discontinuous Galerkin discretization of the compressible Navier-Stokes equations
No full textIn this article we propose a new symmetric version of the
interior penalty discontinuous Galerkin finite element
method for the numerical approximation
of the compressible Navier-Stokes equations. Here, particular
emphasis is devoted to the construction of an optimal numerical
method for the evaluation of certain target functionals of practical
interest, such as the lift and drag coefficients of a body immersed in a
viscous fluid. With this in mind, the key ingredients in the
construction of the method include: (i) An adjoint consistent imposition of
the boundary conditions; (ii) An adjoint consistent reformulation of the
underlying target functional of practical interest; (iii) Design of appropriate
interior--penalty stabilization terms. Numerical experiments presented
within this article clearly indicate the optimality of the proposed
method when the error is measured in terms of both the L2-norm, as well as
for certain target functionals. Computational comparisons with
other discontinuous Galerkin schemes proposed in the literature,
including the second scheme
of Bassi and Rebay, the standard SIPG method
outlined in [Hartmann,Houston-2006], and an NIPG variant of the new scheme
will be undertaken
Robust Mesh Deformation using the Linear Elasticity Equations
No full textA modification is proposed to the equations of linear elasticity as used
to deform Euler and Navier-Stokes meshes. In particular it is seen that the equations
do not admit rigid body rotations as solutions, and it is shown how these solutions
may be recovered by modifying the constitutive law. The result is significantly
more robust to general deformations, and combined with incremental application
generates valid meshes well beyond the point at which remeshing is required
Stokes flow through a single-screw extruder
No full textStokes flow through a single-screw extruder driven either by an axial pressure-gradient, or by the rotation of the screw, or by a combination of both is analyzed. The geometry of the screw is chosen to resemble that encountered in the metering section of a real-life industrial extruder. Working on the simplifying assumption of large helical pitch, a perturbation analysis is performed in non-orthogonal helical coordinates, and contributions to the velocity and pressure fields are computed up to second-order by finite element methods for unidirectional and two-dimensional Stokes flow. Velocity fields are presented for different screw geometries, the axial flow rate is computed for pressure- and rotation-driven flow, comparisons with simple models are made, and the effect of the pitch on the trajectories of passively convected particles is demonstrated. In the case of purely pressure-driven flow, the flow rate decreases, whereas in the case of rotating flow the flow rate increases as the gap between the screw and the barrel is reduced
Dante poeta-profeta, pellegrino, autore : strutturazione espessiva della Commedia e visione escatologica dantesca
No full textLo studio del profetismo dantesco e del rapporto tra esso e la "lupa" (cioè la cupidigia-volontà di potenza, è condotto attraverso l'analisi dei momenti più intensamente profetici del poema: dagli aspetti escatologici, politici e sociali dell'antefatto, attraverso le intense reminiscenze da Ezechiele e da Apocalisse ricontestualizzate in Purg. XIX e XX, alle grandiose visioni escatologico-politiche di Purg. XXXII e XXXIII, alla sommessa e dolente speranza espressa negli ultimi canti di Beatrice.Il grido profetico di Dante è inseparabile dalle diverse immagini del poeta all'interno della Commedia: il poeta-pellegrino (l'agens); il poeta-scriba, addetto a riprodurre le esperienze vissute dal pellegrino; l'autore, cioè il poeta-profeta, il quale dice "io" anch'egli e intervienedal presente della scrittura per ammaestrare il lettore ed esecrare i vizi della cristianità sviata. Si esamina quindi la posizione di Dante tra i poeti-auctores antichi e l'auctoritas che spetta ai libri sacri di AT e di NT.The study of Dantean prophetism and of its relationship with the “she-wolf” (that is greed-lust for power), is carried out through the analysis of the most intensely prophetic moments of the poem: from the eschatological, political and social aspects of the background, through the intense reminiscences from Ezekiel and Apocalypse re-contextualized in Purgatory XIX and XX, to the great eschatological-political visions of Purgatory XXXII and XXXIII, to the quiet and sorrowful hope expressed in Beatrice's last cantos. Dante's prophetic cry is inseparable from the different images of the poet inside the Comedy : the pilgrim poet (the agens); the scribe poet, assigned to reproduce the experiences lived by the pilgrim; the author, that is the prophet poet, who also says “I” and intervenes from the present of the writing to teach the reader and execrate the vices of led astray Christianity. Then Dante's position is examined between the ancient auctores- poets and the auctoritas due to the holy books of the Old and New Testament
Sant'Ambrogio nella letteratura religiosa slava orientale del Sei e Settecento : per uno studio preliminare delle citazioni ambrosiane nell'omiletica rutena barocca
No full textThe aim of this study is to investigate the reception of Ambrose in the writings of three Ukrainian baroque preachers, viz. Ioannikij Galjatovs’kyj, Antonij Radyvylovs’kyj and Dimitrij Rostovskij. The method that has been adopted in the presentation of the results of our survey can be outlined as follows. First, we focused on the thematic aspects of the process of reception, which generally fall into two categories: 1. Exegetical themes, based on motives drawn from the Scriptures; 2. Philosophical-doctrinal themes. Furthermore, for all the writers which we examined we tried to determine whether an author made a direct or indirect usage of Ambrose’s oeuvre. Indirect use is generally to be ascribed to the influence of either exegetic Comments on the Bible, such as those of Cornelius A Lapide and Didacus de Baeza, or of emblematic literature produced in the West, such as Hemannus Hugo’s Pia desideria (1624).
A second question to be addressed is how the intellectual and ecclesiastical context of the Ukrainian lands, whose distinctive features were pluriconfessionalism and the close ties to Western Renaissance and Baroque, influenced our authors in the way they made use of Ambrose, especially as far as the relationship between Orthodoxy and Catholicism is concerned
An unfitted Nitsche method for incompressible fluid-structure interaction using overlapping meshes
No full textWe consider the extension of the Nitsche method to the case of fluid–structure interaction problems on unfitted meshes. We give a stability analysis for the space semi-discretized problem and show how this estimate may be used to derive optimal error estimates for smooth solutions,irrespectively of the mesh/interface intersection. We also discuss different strategies for the time discretization, using either fully implicit or explicit coupling (loosely coupled) schemes. Some numerical examples illustrate the theoretical discussion
Fammi del tuo valor sì fatto vaso, come dimandi a dar l'amato alloro
No full textIl contributo esamina lo sviluppo della possibilità di esistenza di poeti e autori volgari (accanto e in competizione con i classici soprattutto latini)nelle opere di Dante antecedenti la Commedia. Quindi argomenta le ragioni per cui Dante, nella Commedia, si proclama poeta ma non si definisce mai autore (tale in particolare è Virgilio).The contribution considers the development of the possibility of existence of vulgar poets and authors (beside and in competition with the classics, mostly Latin) in Dante's works prior to the Comedy.
Then it argues the reasons why Dante, in the Comedy, declares himself a poet but he never calls himself an author (such is particularly Virgil)
Overlapping parietal activity in memory and perception: evidence for the attention to memory model
No full textThe specific role of different parietal regions to episodic retrieval is a topic of intense debate. According to the Attention to Memory (AtoM) model, dorsal parietal cortex (DPC) mediates top-down attention processes guided by retrieval goals, whereas ventral parietal cortex (VPC) mediates bottom-up attention processes captured by the retrieval output or the retrieval cue. This model also hypothesizes that the attentional functions of DPC and VPC are similar for memory and perception. To investigate this last hypothesis, we scanned participants with event-related fMRI whereas they performed memory and perception tasks, each comprising an orienting phase (top-down attention) and a detection phase (bottom-up attention). The study yielded two main findings. First, consistent with the AtoM model, orienting-related activity for memory and perception overlapped in DPC, whereas detection-related activity for memory and perception overlapped in VPC. The DPC overlap was greater in the left intraparietal sulcus, and the VPC overlap in the left TPJ. Around overlapping areas, there were differences in the spatial distribution of memory and perception activations, which were consistent with trends reported in the literature. Second, both DPC and VPC showed stronger connectivity with medial-temporal lobe during the memory task and with visual cortex during the perception task. These findings suggest that, during memory tasks, some parietal regions mediate similar attentional control processes to those involved in perception tasks (orienting in DPC vs. detection in VPC), although on different types of information (mnemonic vs. sensory)
Een duurzaam thuis: Over waarden in wonen
No full textNederlandse volkshuisvesting draagt van oudsher bij aan een ’waardevolle‘ samenleving. Volkshuisvesting had oorspronkelijk als doel te voorzien in een gezonde woonsituatie voor iedereen en bij te dragen aan een maatschappij waarin kwetsbare groepen middenin de samenleving leven. Dit streven kon lange tijd op breed politiek draagvlak rekenen. Met de introductie van marktwerking in de woonsector kwamen woningcorporaties en hun bijzondere positie tussen markt en overheid onder een vergrootglas te liggen. Het op economische efficiëntie gerichte denken kon niet uit de voetenmet deze vreemde organisaties die niet gericht zijn op winst maar op waarden. In plaats van de waarden expliciet te maken, werd geprobeerd onderscheid te maken tussen de op winst gerichte activiteiten van woningcorporaties en de activiteiten die het algemeen belang dienden. Dit artikel gaat in op de waarden in wonen die nu te vaak impliciet blijven, zoals rechtvaardigheid en duurzaamheid, en voorheen werden aangeduid met het begrip volkshuisvesting.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Housing Institutions & Governanc
A Review of "Housing wealth and welfare", By Caroline Dewilde and Richard Ronald
No full textBook review: Housing wealth and welfare, By Caroline Dewilde and Richard Ronald, Cheltenham, Edward Elgar Publishing, 2017, ISBN 978 78536 095 4.This is a very interesting edited volume comprising an introduction chapter reflecting on so-called housing asset-based welfare and nine chapters written by a nice selection of authors. It is a more than worthwhile joint effort of two excellent ERC laurates who have both been working on the topic for years which is demonstrated in the very comprehensive overview of the state of the art in housing wealth and welfare. They explain different models across time and across Europe: some models are more familialised, relying on family capital, while others are more financialised, relying on mortgages. The introduction is followed by a multi-angle, multi-country collection of well-written chapters. And last but not least, there is an epilogue by John Doling, ‘the father’ of housing asset-based welfare.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.OLD Housing System
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