1,721,513 research outputs found
An Efficient and Modular Approach Dedicated to Dam Breaks
No full textThe paper presents an integrated tool for dam-break hazard modelling. It is based on a two-dimensional, depthaveraged hydraulic model that uses a conservative and shock-capturing finite volume scheme on a Cartesian grid. The hydraulic model is designed so that different zones within the computation domain can be modelled with different spatial resolutions and/ or different model enhancements (e. g. pressurized flows, sediment transport etc.). The twodimensional model can be coupled with lumped models that compute the water stage in reservoirs and the outflow discharge through hydraulic structures in case of normal operating, failure of a valve or breaching processes. These features make hydraulic modelling versatile and computationaly efficient. They enable the definition of different failure scenarios, which is of prominent importance given the uncertainty of such a phenomenon. If several hydraulic structures are involved, the procedure takes the behaviour of each structure into account. The sensitivity of the results with respect to the interactions between the flow and the terrain (roughness coefficient, collapse of buildings, breaching process) can be analysed. The results of the hydraulic model are handled thanks to a graphical user interface that provides one-, two-and three-dimensional views and animations of the unsteady flow field and enables the understanding and verification of the results. Danger maps are generated based on the results of one or more ‘ worstcase’ scenarios. In case of a complete risk analysis, the danger maps are combined with data on the exposure and vulnerability of elements at risk for the computation of the corresponding damage.Stilmant Frédéric, Pirotton Michel, Dewals Benjamin, Erpicum Sébastien, Archambeau Pierre. An Efficient and Modular Approach Dedicated to Dam Breaks. In: SimHydro 2014. New Trends in Simulation. 11-13 June 2014 Ecole Polytech’ Nice (France) 2014
Validation of a SPH model for free surface flows
Full text linkThe SPH method (smoothed particle hydrodynamics) is a numerical meshless, particle and Lagrangian method. It is used in a lot of fields of engineering and science such as solids mechanics, hydraulics and astrophysics. The medium is represented thanks to a set of particles which interact with each other. Nowadays, the SPH method is still under development but is able to deal with a wide range of problems in hydraulics. This article focuses especially on open channel quasi-incompressible flows. While implementing a SPH code, a programmer can face up some difficulties such as the neighbors search, the boundary conditions, the speed of sound or the initialization of the particles. We have drawn some unexpected conclusions concerning the compressibility of the fluid and the way the particles are initialized. This paper presents also a list of test cases that can be performed in order to validate an SPH code. It includes : (a) a tank of still water, (b) a spinning tank and (c) a dam break on a dry bed. These test cases allowed us to highlight some undesired effects. Finally, a new test case is developed. It is based on new experimental results of a flow on a spillway. For this test case, open boundaries have been implemented. The results presented in this paper are based on a 3-D code implemented during a master thesis.Goffin Louis, Erpicum Sébastien, Dewals Benjamin, Pirotton Michel, Archambeau Pierre. Validation of a SPH model for free surface flows. In: SimHydro 2014. New Trends in Simulation. 11-13 June 2014 Ecole Polytech’ Nice (France) 2014
La dynamique des fluides numérique pour guider la recherche des victimes de noyade dans les rivières urbaines
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Bystander influence of nematode exposure on subsequent herpesvirus infections in vivo
Full text linkParasitic worms have the ability to modulate the hosts immune response to promote host control of the infection and also parasite survival in the host. Helminth infections classically induce a potent Th2-biased and regulatory immune imprint. This immune response also influences unrelated inflammatory processes in the host. Studies have shown helminth infections have bystander influences on unrelated conditions such as allergy and autoimmunity. Additionally, helminth infections can alter susceptibility to other infections. In this thesis, we investigate the systemic influences of murine nematode Nippostrongylus brasiliensis infection on host immunity in colonized and non-colonized tissues, and the implications of these effects on susceptibility to subsequent herpesvirus infections in vivo. We show that prior N. brasiliensis infection enhanced control of acute respiratory murid gammaherpesvirus (MuHV-4) infection, with an increase in viral-specific CD8+ T cells in colonized lung tissue. Enhanced effector cytokine responses by cytotoxic T cells were also observed with prior helminth exposure. Conversely, despite enhanced primary control, prior helminth exposure was associated with earlier and heightened genital reactivation of MuHV4. This demonstrates differences in local bystander and systemic effects of helminth exposure on the host, and on unrelated viral infections. We also show that N. brasiliensis infection, which transits the respiratory and gastrointestinal tracts, also systemically influences immunity in the female genital tract (FGT) in vivo. Here, helminth infection induced Th2-type immunity in the FGT, namely increased tissue IL-4, IL-5 and long-lasting eosinophilia. We further demonstrated that systemic influences of N. brasiliensis infection results in exacerbated genital pathology and inflammation, following subsequent intravaginal herpes simplex virus type II (HSV-2) infection. Increased HSV-2 pathology with prior helminth exposure was associated with diminished innate anti-viral immunity, increased IL-33, ILC2 and IL-5 responses, as well as significant eosinophilia. Interestingly, abolition of canonical Th2 immune signalling by the lack of IL-4Rα expression, enhanced innate anti-viral defences and provided protection from HSV-2 pathology. However, N. brasiliensis-induced exacerbation of HSV-2 illness was IL-4Rαindependent, associated with significant genital eosinophilia. Furthermore, antibody-depletion of eosinophils ameliorated nematode-exacerbated HSV-2 pathology, suggesting that nematode-induced genital eosinophilia mediates increased HSV-2 pathology in coinfected mice. We have therefore shown that helminth infections can induce local and systemic bystander immunity to lymphoid and myeloid immune compartments, which alters susceptibility to subsequent herpesvirus infections
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Immuno-évasion de la réponse cytotoxique par la protéine de maintenance génomique de l'herpèsvirus alcélaphin 1
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