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See detailA 2D finite volume multiblock flow solver applied to flood extension forecasting
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Detrembleur, Sylvain ULg et al

in García-Navarro, Pilar; Playán, Enrique (Eds.) Numerical modelling of hydrodynamics for water ressources (2008)

ABSTRACT: this paper describes a quasi-3D free surface flow solver,developed for almost ten years at the University of Liege, and its application to flood extension forecasting. Based on the classical SWE ... [more ▼]

ABSTRACT: this paper describes a quasi-3D free surface flow solver,developed for almost ten years at the University of Liege, and its application to flood extension forecasting. Based on the classical SWE, the finite volume numerical model deals with real topography and wetting-drying cells while exactly conserving the water volume. Multiblock options allow local refine-ment of the structured calculation grid and automatic mesh refinement enhances greatly compu-tation time. An additional depth-averaged k-ε type turbulence model increases the potentialities of the solver to represent real complex flows. Following a Regional Government decision, this solver has been officially chosen in 2003 to be used to compute inundation maps on 800 km of the main rivers of the Walloon Region in Belgium with a spatial resolution of 5 x 5 to 2 x 2 me-ters and using high resolution Digital Elevation Models. Results are presented in this paper. [less ▲]

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See detail2D Harmonic Balance FE Modelling of Electromagnetic Devices coupled to Nonlinear Circuits
Gyselinck, J.; Dular, Patrick ULg; Geuzaine, Christophe ULg et al

in COMPEL (2004), 23(3), 800--812

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See detail2D non-perturbative modeling of oscillations in rapidly rotating stars
Ouazzani, Rhita-Maria ULg; Dupret, Marc-Antoine ULg; Goupil, M. J. et al

in Astronomical Notes (2010), 331

We present and discuss results of a recently developped two dimensional non-perturbative method to compute accurate adiabatic oscillation modes of rapidly rotating stars . The 2D calculations fully take ... [more ▼]

We present and discuss results of a recently developped two dimensional non-perturbative method to compute accurate adiabatic oscillation modes of rapidly rotating stars . The 2D calculations fully take into account the centrifugal distorsion of the star while the non-perturbative method includes the full influence of the Coriolis acceleration. These characteristics allows us to compute oscillation modes of rapid rotators - from high order p-modes in $\delta$Scuti stars, to low order p- and g-modes in $\beta$ Cephei or Be stars. [less ▲]

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See detail2D numerical flow modeling in a macro-rough channel
Erpicum, Sébastien ULg; Meile, Tobias; Dewals, Benjamin ULg et al

in International Journal for Numerical Methods in Fluids (2009), 61(11), 1227-1246

A 2D numerical flow model, developed at the Research unit of Hydrology, Applied Hydrodynamics and Hydraulic Constructions at ULg, has been applied to flows in a macro-rough channel. The model solves the ... [more ▼]

A 2D numerical flow model, developed at the Research unit of Hydrology, Applied Hydrodynamics and Hydraulic Constructions at ULg, has been applied to flows in a macro-rough channel. The model solves the shallow water equations (SWE) with a two length scale, depth-integrated k-type approach for turbulence modeling. Data for the comparison have been provided by experiments conducted at the Laboratory of Hydraulic Constructions at EPFL. In the experiments with different non-prismatic channel configurations, namely large-scale cavities at the side walls, three different 2D flow characteristics could be observed in cavities. With the used numerical model features, especially regarding turbulence and friction modeling, a single set of bottom and side wall roughness could be found for a large range of discharges investigated in a prismatic channel. For the macro rough configurations, the numerical model gives an excellent agreement between experimental and numerical results regarding backwater curves and flow patterns if the side wall cavities have low aspect ratios. For configurations with high aspect ratios, the head loss generated by the preservation of important recirculation gyres in the cavities is slightly underestimated. The results of the computations reveal clearly that the separation of turbulence sources in the mathematical model is of great importance. Indeed, the turbulence related to 2D transverse shear effects and the 3D turbulence, generated by bed friction, can have very different amplitude. When separating these two effects in the numerical models, most of the flow features observed experimentally can be reproduced accurately. [less ▲]

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See detail2D to 3D crossover of the magnetic properties in ordered arrays of iron oxide nanocrystals
Faure, Bertrand; Wetterskog, Erik; Gunnarsson, Klas et al

in NANOSCALE (2013), 5(3), 953-960

The magnetic 2D to 3D crossover behavior of well-ordered arrays of monodomain gamma-Fe2O3 spherical nanoparticles with different thicknesses has been investigated by magnetometry and Monte Carlo (MC ... [more ▼]

The magnetic 2D to 3D crossover behavior of well-ordered arrays of monodomain gamma-Fe2O3 spherical nanoparticles with different thicknesses has been investigated by magnetometry and Monte Carlo (MC) simulations. Using the structural information of the arrays obtained from grazing incidence small-angle X-ray scattering and scanning electron microscopy together with the experimentally determined values for the saturation magnetization and magnetic anisotropy of the nanoparticles, we show that MC simulations can reproduce the thickness-dependent magnetic behavior. The magnetic dipolar particle interactions induce a ferromagnetic coupling that increases in strength with decreasing thickness of the array. The 2D to 3D transition in the magnetic properties is mainly driven by a change in the orientation of the magnetic vortex states with increasing thickness, becoming more isotropic as the thickness of the array increases. Magnetic anisotropy prevents long-range ferromagnetic order from being established at low temperature and the nanoparticle magnetic moments instead freeze along directions defined by the distribution of easy magnetization directions. [less ▲]

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See detailA 2D vertical finite volume solver using a level set approach for simulating free surface incompressible flows
Detrembleur, Sylvain ULg; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

in European Journal of Mechanical and Environmental Engineering (2009), 2009(3), 4-9

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See detail2D XFEM-based modeling of retraction and successive resections for preoperative image update.
Vigneron, Lara M.; Duflot, Marc P.; Robe, Pierre ULg et al

in Computer aided surgery : official journal of the International Society for Computer Aided Surgery (2009), 14(1-3), 1-20

This paper considers an approach to improving outcomes for neurosurgery patients by enhancing intraoperative navigation and guidance. Currently, intraoperative navigation systems do not accurately account ... [more ▼]

This paper considers an approach to improving outcomes for neurosurgery patients by enhancing intraoperative navigation and guidance. Currently, intraoperative navigation systems do not accurately account for brain shift or tissue resection. We describe how preoperative images can be incrementally updated to take into account any type of brain tissue deformation that may occur during surgery, and thus to improve the accuracy of image-guided navigation systems. For this purpose, we have developed a non-rigid image registration technique using a biomechanical model, which deforms based on the Finite Element Method (FEM). While the FEM has been used successfully for dealing with deformations such as brain shift, it has difficulty with tissue discontinuities. Here, we describe a novel application of the eXtended Finite Element Method (XFEM) in the field of image-guided surgery in order to model brain deformations that imply tissue discontinuities. In particular, this paper presents a detailed account of the use of XFEM for dealing with retraction and successive resections, and demonstrates the feasibility of the approach by considering 2D examples based on intraoperative MR images. To evaluate our results, we compute the modified Hausdorff distance between Canny edges extracted from images before and after registration. We show that this distance decreases after registration, and thus demonstrate that our approach improves alignment of intraoperative images. [less ▲]

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See detail2D-Vertical Model for Free Surface Incompressible Flows: Validation and Applications
Detrembleur, Sylvain; Dewals, Benjamin ULg; Pirotton, Michel ULg

in Proc. 34th IAHR World Congress - Balance and Uncertainty (2011)

Efficient design of hydraulic structures such as weirs and bottom outlets requires a detailed description of the complex turbulent flows occurring on these structures. Compared to laboratory experiments ... [more ▼]

Efficient design of hydraulic structures such as weirs and bottom outlets requires a detailed description of the complex turbulent flows occurring on these structures. Compared to laboratory experiments, numerical modeling offers more flexibility and cost-effectiveness to test different designs. The non-hydrostatic 2D-vertical model presented here solves the RANS equations for incompressible flows in the vertical plane. It is based on the projection method for pressure-velocity coupling, while free surface tracking is conducted by means of the level set technique and Sussman’s velocity extension algorithm. It enables to predict accurately the flow pattern in the vertical plane and deals with multiple interfaces (jets, drops…). The solver has been validated for both steady and unsteady free surface flows, based on theoretical and experimental data. The paper will detail the application of the model to a pressurized flow and to a sloshing tank. [less ▲]

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See detail2D1/2 Thermal-Mechanical Model of Continuous Casting of Steel Using Finite Element Method
Pascon, Frédéric ULg

Doctoral thesis (2002)

The thesis deals with a numerical model based on the finite element method applied to the continuous casting of steel. The model is developed using the LAGAMINE finite element code and two industrial ... [more ▼]

The thesis deals with a numerical model based on the finite element method applied to the continuous casting of steel. The model is developed using the LAGAMINE finite element code and two industrial applications of steel casting are presented to illustrate the capabilities of the model. The first chapter introduces the continuous casting process, defining the essential terminology and the industrial challenges. Then, the objectives of the model are detailed: the model is applied to the upper part of the caster (in the mould region) as well as to the bending and straightening zones. Chapters two, three and four are dedicated to the theoretical developments of thermal aspects (phase transformations, thermal contraction, heat flow and thermal boundary conditions), mechanical aspects (generalized plain strain state, material constitutive law, ferrostatic pressure and mechanical contact) and the staggered analysis used for thermal / mechanical coupling. In the two next chapters, some numerical results are presented. The model has been first applied to a 125mm square billet in the mould region. The industrial goal is to evaluate the effect of the mould taper on the cooling of the billet (temperature evolution, solid shell growing, stress and strain development). The second application focuses on the risk of transverse cracking during straightening of steel slabs and the effect of some local defects (reduction of secondary cooling, locking or misalignment of rolls). The thesis ends with some concluding remarks and perspectives for the model. [less ▲]

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See detail2D1/2 thermo-mechanical model of continuous casting using FEM
Pascon, Frédéric ULg; Habraken, Anne ULg

in Brucato, V. (Ed.) Proceedings of the 6th International ESAFORM Conference on Material Forming (2003)

Two complementary approaches of steel continuous casting modelling using the finite element code LAGAMINE have been developed in the M&S Department. The first one (at a macroscopic scale) describes the ... [more ▼]

Two complementary approaches of steel continuous casting modelling using the finite element code LAGAMINE have been developed in the M&S Department. The first one (at a macroscopic scale) describes the whole continuous casting process, from the free surface in the mould and through the entire machine, including thermal and mechanical behaviour of the steel. The second approach focuses on the prediction of cracks and is developed at grain scale. We present in this paper a description of the context in which the study started, the description of the macroscopic approach and some results. [less ▲]

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See detail2e campagne de fouille à Chagar Bazar (Syrie)
Tunca, Önhan ULg; McMahon, A.; Baghdo, Abd el-Massih

in Orient-Express 2000/4 (2000)

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See detail2ème Atelier Nitrate - Eau. Evaluation du Programme de Gestion Durable de l'Azote
Vandenberghe, Christophe ULg; Colinet, Gilles ULg; Destain, Jean-Pierre ULg et al

Book published by Presses Agronomiques de Gembloux (2013)

Under the four-year review of the program of action for the implementation of the Nitrates Directive in the Walloon region, a workshop was held a couple of scientists to assess the current program and to ... [more ▼]

Under the four-year review of the program of action for the implementation of the Nitrates Directive in the Walloon region, a workshop was held a couple of scientists to assess the current program and to propose ways of improvement [less ▲]

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See detail2ème BBM - ostéoporose
CAVALIER, Etienne ULg

Learning material (2011)

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See detail2F3 Monoclonal Antibody Recognizes the O26 O-Antigen Moiety of the Lipopolysaccharide of Enterohemorrhagic Escherichia coli Strain 4276
Szalo, Ioan Mihai ULg; Taminiau, Bernard ULg; Goffaux, Frédéric et al

in Clinical and Diagnostic Laboratory Immunology (2004), 11(3), 532-537

Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) organisms are groups of pathogenic strains whose infections are characterized by a typical lesion of enterocyte attachment and ... [more ▼]

Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) organisms are groups of pathogenic strains whose infections are characterized by a typical lesion of enterocyte attachment and effacement. They are involved in enteric diseases both in humans and in animals, and EHEC strains can be responsible for hemolytic uremic syndrome in humans. Previously, it was shown that the 2F3 monoclonal antibody (MAb) is specific for the O26 EHEC and EPEC strains (P. Kerr, H. Ball, B. China, J. Mainil, D. Finlay, D. Pollock, I. Wilson, and D. Mackie, Clin. Diagn. Lab. Immunol. 6:610–614, 1999). As these groups of bacteria play an important role in pathology, the aim of this paper was to characterize the antigen recognized by the 2F3 MAb and its genetic determinant. A genomic locus containing the entire O-antigen gene cluster and half of the colanic acid gene cluster from an O26 EHEC strain was shown to be sufficient for the production of the antigen recognized by the 2F3 MAb in an E. coli DH5 strain. By transposon mutagenesis performed on the recombinant plasmid, all 2F3 enzyme-linked immunosorbent assay-negative mutants had their transposons inserted into the O-antigen gene cluster. The O-antigen gene cluster was also cloned from an O26 EHEC strain into the E. coli DH5 strain, which then produced a positive result with the 2F3 MAb. Further analysis of the type of lipopolysaccharides (smooth or rough) produced by the clones and mutants and of the O antigen of the 2F3-positive clones confirmed that the epitope recognized by the 2F3 MAb is located on the O antigen in the O26 EHEC and EPEC strains and that its genetic determinant is located inside the O-antigen gene cluster. [less ▲]

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See detailThe 2nd Workshop on Active Internet Measurements (AIMS-2) Report
claffy, kc; Aben, Emile; Auge, Jorge, et al

in Computer Communication Review (2010), 40(5), 53-58

On February 8-10, 2010, CAIDA hosted the second Work- shop on Active Internet Measurements (AIMS-2) as part of our series of Internet Statistics and Metrics Analysis (ISMA) workshops. The goals of this ... [more ▼]

On February 8-10, 2010, CAIDA hosted the second Work- shop on Active Internet Measurements (AIMS-2) as part of our series of Internet Statistics and Metrics Analysis (ISMA) workshops. The goals of this workshop were to further our understanding of the potential and limitations of active mea- surement research and infrastructure in the wide-area Inter- net, and to promote cooperative solutions and coordinated strategies to addressing future data needs of the network and security research communities. The three-day workshop included presentations, group discussion and analysis, and focused interaction between participating researchers, oper- ators, and policymakers from all over the world. This report describes the motivation and findings of the workshop, and reviews progress on recommendations developed at the 1st Active Internet Measurements Workshop in 2009 [18]. Slides from the workshop presentations are available at [9]. [less ▲]

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See detail3 ',4 ',5 ',6 ' tetradehydrolongicaudatine Y, an anhydronium base from Strychnos usambarensis
Frederich, Michel ULg; Quetin-Leclercq, J.; Biala, R. G. et al

in Phytochemistry (1998), 48(7), 1263-1266

Detailed reference viewed: 19 (5 ULg)