52 research outputs found

    Benefits of using a Wendland Kernel for free-surface flows

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    The aim of this paper Is lo discuss the influence of the selection of the interpolation kernel in the accuracy of the modeling of the internal viscous dissipation in Tree surface Hows, Simulations corresponding to a standing wave* for which an analytic solution available, are presented. Wendland and renormalized Gaussian kernels are considered. The differences in the flow pattern* and Internal dissipation mechanisms are documented for a range of Reynolds numbers. It is shown that the simulations with Wendland kernels replicate the dissipation mechanisms more accurately than those with a renormalized Gaussian kernel. Although some explanations are hinted we have Tailed to clarify which the core structural reasons for Mich differences are

    On the non-slip boundary condition enforcement in SPH methods.

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    The implementation of boundary conditions is one of the points where the SPH methodology still has some work to do. The aim of the present work is to provide an in-depth analysis of the most representative mirroring techniques used in SPH to enforce boundary conditions (BC) along solid profiles. We specifically refer to dummy particles, ghost particles, and Takeda et al. [1] boundary integrals. A Pouseuille flow has been used as a example to gradually evaluate the accuracy of the different implementations. Our goal is to test the behavior of the second-order differential operator with the proposed boundary extensions when the smoothing length h and other dicretization parameters as dx/h tend simultaneously to zero. First, using a smoothed continuous approximation of the unidirectional Pouseuille problem, the evolution of the velocity profile has been studied focusing on the values of the velocity and the viscous shear at the boundaries, where the exact solution should be approximated as h decreases. Second, to evaluate the impact of the discretization of the problem, an Eulerian SPH discrete version of the former problem has been implemented and similar results have been monitored. Finally, for the sake of completeness, a 2D Lagrangian SPH implementation of the problem has been also studied to compare the consequences of the particle movemen

    Fratura de côndilo occipital associada a fratura de Jefferson e lesão dos nervos cranianos caudais: relato de caso

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    Occipital condyle fracture (OCF) is rarely seen and can be missed during medical evaluation due to the variety of clinical presentations and the difficulty to be visualized radiographically. This fracture can be associated with cranial nerves injuries (31%), being the hipoglossal nerve the most frequently involved (67%). We report a 58 years old female patient who presented with OCE, injury of lower cranial nerves and Jefferson's fracture. the patient was treated with cervical traction for six weeks followed by halo immobilization for three months. There was bone consolidation recovery of the nervous injury after this period. This report emphazises the importance of investigating the skull-cervical transition in all patients with cervical trauma. Although Jefferson's fracture is rarely associated with OCF, it should be remembered and treated appropriately when diagnosed.Univ Caxias Sul, Disciplina Neruol, Caxias Do Sul, RS, BrazilUNIFESP, São Paulo, BrazilUniv Caxias Sul, Acad Ano Curso Grad & Med 6, Caxias Do Sul, RS, BrazilUNIFESP, São Paulo, BrazilWeb of Scienc

    WCSPH viscosity diffusion processes in vortex flows

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    The aim of this paper is to clarify the role played by the most commonly used viscous terms in simulating viscous laminar flows using the weakly compressible approach in the context of smooth particle hydrodynamics (WCSPH). To achieve this, Takeda et al. (Prog. Theor. Phys. 1994; 92(5):939–960), Morris et al. (J. Comput. Phys. 1997; 136:214–226) and Monaghan–Cleary–Gingold's (Appl. Math. Model. 1998; 22(12):981–993; Monthly Notices of the Royal Astronomical Society 2005; 365:199–213) viscous terms will be analysed, discussing their origins, structures and conservation properties. Their performance will be monitored with canonical flows of which related viscosity phenomena are well understood, and in which boundary effects are not relevant. Following the validation process of three previously published examples, two vortex flows of engineering importance have been studied. First, an isolated Lamb–Oseen vortex evolution where viscous effects are dominant and second, a pair of co-rotating vortices in which viscous effects are combined with transport phenomena. The corresponding SPH solutions have been compared to finite-element numerical solutions. The SPH viscosity model's behaviour in modelling the viscosity related effects for these canonical flows is adequat

    The protein LJM 111 from Lutzomyia longipalpis Salivary Gland Extract (SGE) accounts for the SGE-inhibitory effects upon inflammatory parameters in experimental arthritis model

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    Several studies have pointed out the immunomodulatory properties of the Salivary Gland Extract (SGE) from Lutzomyia longipalpis. We aimed to identify the SGE component (s) responsible for its effect on ovalbumin (OVA)-induced neutrophil migration (NM) and to evaluate the effect of SGE and components in the antigen-induced arthritis (AIA) model. We tested the anti-arthritic activities of SGE and the recombinant LJM111 salivary protein (rLJM111) by measuring the mechanical hypernociception and the NM into synovial cavity. Furthermore, we measured IL-17, TNF-alpha and IFN-gamma released by lymph nodes cells stimulated with mBSA or anti-CD3 using enzyme-linked immunosorbent assay (ELISA). Additionally, we tested the effect of SGE and rLJM111 on co-stimulatory molecules expression (MHC-II and CD-86) by flow cytometry. TNF-alpha and IL-10 production (ELISA) of bone marrow-derived dendritic cells (BMDCs) stimulated with LPS, chemotaxis and actin polymerization from neutrophils. Besides, the effect of SGE on CXCR2 and GRK-2 expression on neutrophils was investigated. We identified one plasmid expressing the protein LJM111 that prevented NM in OVA-challenged immunized mice. Furthermore, both SGE and rLJM111 inhibited NM and pain sensitivity in AIA and reduced IL-17, TNF-alpha and IFN-gamma. SGE and rLJM111 also reduced MHC-II and CD-86 expression and TNF-alpha whereas increased IL-10 release by LPS-stimulated BMDCs. SGE, but not LJM 111, inhibited neutrophils chemotaxis and actin polymerization. Additionally, SGE reduced neutrophil CXCR2 expression and increased GRK-2. Thus, rLJM111 is partially responsible for SGE mechanisms by diminishing DC function and maturation but not chemoattraction of neutrophils. (C) 2012 Elsevier B.V. All rights reserved

    Adaptación de las asignaturas básicas de primer curso de la ETSI Navales de la UPM: Actividades 2008-2009

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    En el marco de la reforma de las titulaciones con motivo del Espacio Europeo de Educación un grupo de profesores hemos coordinado, durante el curso 2008-2009, todas las asignaturas básicas de primer curso y una más de segundo curso en la Escuela Técnica Superior de Ingenieros Navales. Las actividades realizadas son: a) Coordinación de todas las asignaturas básicas de primer curso, con reuniones periódicas de coordinación horizontal y el establecimiento de una página web de moodle para profesores como espacio para el trabajo cooperativo. Particularmente importante es el establecimiento de un calendario conjunto de pruebas de evaluación continua. b) Redacción de guías de aprendizaje, con un formato común para todas las asignaturas, incluyendo los objetivos formativos, los contenidos, las actividades formativas, los enlaces y la bibliografía. c) Establecimiento de una plataforma de teleeducación común para todas las asignaturas, uno de los objetivos fundamentales del proyecto, ya que coexistían dos plataformas distintas. Igualmente importante ha sido reforzar los contenidos y las actividades que se podían realizar en la plataforma. d) Seguimiento del tiempo dedicado por los alumnos, hemos ido siguiendo el tiempo dedicado por los alumnos a las distintas asignaturas, para detectar si el tiempo que se dedica está en los márgenes establecidos en los créditos ECTS. Igualmente, hemos hecho dos encuestas a la mitad de cada semestre, para recoger las opiniones de los alumnos sobre las asignaturas y sobre los aspectos relevantes del proyecto. e) Organización de actividades de nivelación, para los alumnos de nuevo ingreso, con la organización de cursos cero y la participación y coordinación en la Plataforma de Punto de inicio de la UPM. f) Organización de actividades formativas, para poder llevar a cabo estas tareas, hemos organizado, en colaboración con el Centro y el Gabinete de Tele-Educación (GATE) actividades formativas relacionadas con la plataforma moodle, métodos de evaluación y de formación en competencias.En la presentación haremos una descripción de las actividades realizadas, así como una primera evaluación de las mismas. Por último, describiremos las tareas a desarrollar en los próximos cursos

    Adaptación de las asignaturas básicas de primer curso de la ETSI Navales de la UPM: Primeras experiencias

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    En el marco de la reforma de las titulaciones con motivo de la puesta en marcha del Espacio Europeo de Educación Superior, un grupo de profesores hemos decidido coordinar todas las asignaturas básicas de primer curso y una asignatura de segundo curso en la Escuela Técnica Superior de Ingenieros Navales de la Universidad Politécnica de Madrid con el fin de dar una visión mas homogénea y compacta al alumno de lo que debe ser la formación básica del ingeniero. Para llevar a cabo dicho fin, la Universidad nos ha concedido un Proyecto de Innovación Educativa en la convocatoria 2008 para poder alcanzar una serie de objetivos en el curso 2008-2009, como son la coordinación de todas las asignaturas básicas de primer curso, la aplicación de nuevas metodologías en la práctica educativa, y una mejor adaptación de los alumnos de nuevo ingreso
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