616 research outputs found
The "Oratio de rosis" by Iohannes Sylvius
No full textEste artículo da a conocer y presenta a un humanista danés y una de sus obras que hasta el momento resultaban muy poco conocidos. Se hace un análisis descriptivo del mundo simbólico de la rosa contenido en la Oratio de rosis de Juan Silvio. Se tratan los siguientes puntos: autor, génesis y fuentes de la obra, y motivos simbólicos de la rosa. Se concluye que estamos ante una pieza oratoria perteneciente al genus demostrativum, una laudatio destinada a ensalzar a su protector Holger Rosenkrantz.This paper presents a Lutheran Danish humanist and one of his works, of which very little has been known to date. It provides a descriptive analysis of the symbolic meanings of the rose in Iohannes Sylvius’s Oratio de rosis. The article discusses the author, the genesis of the work and its sources, alongside the symbolic motives of the rose. I conclude that the speech belongs to the genre of epideictic oratory (the genus demonstrativum) and aims to praise the patron of the author, Holger Rosenkranz.peerReviewe
On the dynamics of a tandem of asynchronous flapping wings: Lattice Boltzmann-immersed boundary simulations
No full textIn this paper, the flight performance of a tandem of symmetric flapping wings immersed in a viscous fluid is investigated. A harmonic motion is imposed to the wings which can travel only in the vertical direction. Specifically, the attention focuses on the role of the initial phase difference. The fluid domain is modeled through the lattice Boltzmann method. In order to account for the presence of the wings immersed in the lattice fluid background, the immersed boundary method is adopted. Once fluid forces acting upon the wings are computed, their position is updated by solving the equation of solid motion by the time discontinuous Galerkin method according to a strategy already validated by the author. A wide numerical campaign is carried out by varying the initial phase difference. Moreover, scenarios accounting for the presence of a lateral wind gust are shown. The flight conditions and performance are discussed for a wide set of configurations and compared with an in-sync configuration, showing that the wind gust reduces the performance in certain scenario
Lattice Boltzmann simulations of flapping wings: the flock effect and the lateral wind effect
No full textIn this paper, numerical analysis aiming at simulating biological organisms immersed in a fluid are carried out. The fluid domain is modeled through the lattice Boltzmann (LB) method, while the immersed boundary method is used to account for the position of the organisms idealized as rigid bodies. The time discontinuous Galerkin method is employed to compute body motion. An explicit coupling strategy to combine the adopted numerical methods is proposed. The vertical take-off of a couple of butterflies is numerically simulated in different scenarios, showing the mutual interaction that a butterfly exerts on the other one. Moreover, the effect of lateral wind is investigated. A critical threshold value of the lateral wind is defined, thus corresponding to an increasing arduous take-off
A lattice Boltzmann-finite element model for two-dimensional fluid-structure interaction problems involving shallow waters
No full textIn this paper, a numerical method for the modeling of shallow waters interacting with slender elastic structures is presented. The fluid domain is modeled through the lattice Boltzmann method, while the solid domain is idealized by corotational beam finite elements undergoing large displacements. Structure dynamics is predicted by using the time discontinuous Galerkin method and the fluid–structure interface conditions are handled by the Immersed Boundary method. An explicit coupling strategy to combine the adopted numerical methods is proposed and its effectiveness is tested by computing the error in terms of the energy that is artificially introduced at the fluid–solid interface
ANALYSIS OF BLOOD FLOW IN DEFORMABLE VESSELS VIA A LATTICE BOLTZMANN APPROACH
No full textIn this paper, the lattice Boltzmann (LB) method is used in order to simulate non-Newtonian blood flows in deformable vessels. Casson's rheological model is adopted and a local correction to the relaxation time is implemented in order to modify the viscosity. The hyperelastic, hardening and anisotropic behavior of a flexible arterial wall is discussed and a closed-form solution is used to predict the deformed configuration of the vessel. A partitioned staggered-explicit strategy to couple the LB method and such analytical prediction is proposed
Harmonic oscillations of laminae in non-Newtonian fluids: a lattice Boltzmann-immersed boundary approach
No full textIn this paper, the fluid dynamics induced by a rigid lamina undergoing harmonic oscillations in a non-Newtonian calm fluid is investigated. The fluid is modelled through the lattice Boltzmann method and the flow is assumed to be nearly incompressible. An iterative viscosity-correction based procedure is proposed to properly account for the non-Newtonian fluid feature and its accuracy is evaluated. In order to handle the mutual interaction between the lamina and the encompassing fluid, the Immersed Boundary method is adopted. A numerical campaign is performed. In particular, the effect of the non-Newtonian feature is highlighted by investigating the fluid forces acting on a harmonically oscillating lamina for different values of the Reynolds number. The findings prove that the non-Newtonian feature can drastically influence the behaviour of the fluid and, as a consequence, the forces acting upon the lamina. Several considerations are carried out on the time history of the drag coefficient and the results are used to compute the added mass through the hydrodynamic function. Moreover, the computational cost involved in the numerical simulations is discussed. Finally, two applications concerning water resources are investigated: the flow through an obstructed channel and the particle sedimentation. Present findings highlight a strong coupling between the body shape, the Reynolds number, and the flow behaviour inde
A lattice Boltzmann model for multiphase flows interacting with deformable bodies
No full textIn this paper, a numerical model to simulate a multiphase flow interacting with deformable solid bodies is proposed. The fluid domain is modeled through the lattice Boltzmann method and the Shan-Chen model is adopted to handle the multiphase feature. The interaction of the flow with immersed solid bodies is accounted for by using the Immersed Boundary method. Corotational beam finite elements are used to model the deformable bodies and non-linear structure dynamics is predicted through the Time Discontinuous Galerkin method. A numerical campaign is carried out in order to assess the effectiveness and accuracy of the proposed modeling by involving different scenarios. In particular, the model is validated by performing the bubble test and by comparing present results with the ones from a numerical commercial software. Moreover, the properties in terms of convergence are discussed. In addition, the effectiveness of the proposed methodology is evaluated by computing the error in terms of the energy that is artificially introduced in the system at the fluid-solid interface. Present findings show that the proposed approach is robust, accurate and suitable of being applied to a lot of practical applications involving the interaction between multiphase flows and deformable solid bodies
Soutenance de thèse de Carolina De Rosis
No full textCarolina De Rosis (EHESS-IMAF) soutiendra sa thèse en anthropologie sociale intitulée : “Exercices et constructions du pouvoir aux marges de la cité : la participation des femmes à la lutte contre le VIH/sida en Éthiopie, entre marginalité et mobilité sociale” sous la direction de Jean-Pierre Dozon. La soutenance aura lieu le mercredi 18 octobre à 14h, à l’EHESS, salle A07_51, 54 bd Raspail, 75006 Paris Le jury est ainsi composé : Laetitia Atlani-Duault, DR IRD - prérapporteur Jean-Pierre Doz..
Basic ICT adoption and use by general practitioners: an analysis of primary care systems in 31 European countries
No full textThere is general consensus that appropriate development and use of information and communication technologies (ICT) are crucial in the delivery of effective primary care (PC). Several countries are defining policies to support and promote a structural change of the health care system through the introduction of ICT. This study analyses the state of development of basic ICT in PC systems of 31 European countries with the aim to describe the extent of, and main purposes for, computer use by General Practitioners (GPs) across Europe. Additionally, trends over time have been analysed
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