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See detailThe Portugal coastal counter current off NW Spain: new insights on its biogeochemical variability
Alvarez-Salgado, Xosé Antón; Figueiras, F. G.; Perez, F. F. et al

in Progress in Oceanography (2003), 56(2), 281-321

Time series of wind-stress data, AVHRR and SeaWiFS satellite images, and in situ data from seven cruises are used to assemble a coherent picture of the hydrographic variability of the seas off the ... [more ▼]

Time series of wind-stress data, AVHRR and SeaWiFS satellite images, and in situ data from seven cruises are used to assemble a coherent picture of the hydrographic variability of the seas off the Northwest Iberian Peninsula from the onset (September-October) to the cessation (February-May) of the Portugal coastal counter current (PCCC). During this period the chemistry and the biology of the shelf, slope and ocean waters between 40degrees and 43degreesN have previously been undersampled. Novel information extracted from these observations relate to: 1. The most frequent modes of variability of the alongshore coastal winds, covering event, seasonal and long-term scales; 2. The conspicuous cycling between stratification and homogenisation observed in PCCC waters, which has key implications for the chemistry and biology of these waters; 3. The seasonal evolution of nitrite profiles in PCCC waters in relation to the stratification cycle; 4. The Redfield stoichiometry of the remineralisation of organic matter in Eastern North Atlantic Central Water (ENACW)-the water mass being transported by the PCCC; 5. The separation of coastal (mesotrophic) from PCCC (oligotrophic) planktonic populations by a downwelling front along the shelf, which oscillates to and fro across the shelf as a function of coastal wind intensity and continental runoff; and 6. The photosynthetic responses of the PCCC and coastal plankton populations to the changing stratification and light conditions from the onset to the cessation of the PCCC. [less ▲]

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See detailThe thymic insulin-like growth factor axis: Involvement in physiology and disease
Geenen, Vincent ULg

in Hormone & Metabolic Research (2003), 35(11-12, Nov-Dec), 656-663

A repertoire of neuroendocrine-related genes is transcribed in the non-lymphoid compartment of the thymus, transposing the dual physiological role of this organ at the molecular level in T-cell ... [more ▼]

A repertoire of neuroendocrine-related genes is transcribed in the non-lymphoid compartment of the thymus, transposing the dual physiological role of this organ at the molecular level in T-cell development towards the establishment of central T-cell self-tolerance. The "neuroendocrine self" has been defined as a series of antigen sequences processed from precursors predominantly expressed in the thymus and first encountered by differentiating T-lymphocytes in their early life. All the members of the insulin gene family are expressed in the thymus according to a precise hierarchy and cellular topography, whereby IGF-II (epithelium of the subcapsular cortex and medulla) exceeds IGF-I (macrophages), which in turn far exceeds INS (rare subsets of medullary epithelial cells). This hierarchy in the degree of their respective thymic expression explains why IGF-II is more tolerated than IGF-I, and much more so than insulin. Evidence has been found for significant regulatory/tolerogenic properties in the IGF-II B:11-25 sequence after analysis of the cytokine secretion profile in peripheral blood mononuclear cells isolated from ten DQ8+ type 1 diabetic adolescents. In the thymus, IGF ligands and receptors also intervene in the control of T-cell proliferation and differentiation. Here, we also discuss how a disturbance in the intrathymic IGF-mediated signaling could contribute to the pathogenesis of T-cell leukemia. [less ▲]

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See detailIlmenite deposits and their geological environment (with special reference to the Rogaland Anorthosite province, including a geological map at scale 1:75,000)
Duchesne, Jean-Clair ULg; Korneliussen, Are

Book published by NGU (2003)

The Rogaland Anorthosite Province comprises three major massif-type anorthosites, two smaller-sized anorthositic-leuconoritic bodies, as well as a large layered, dominantly noritic intrusion. A mangero ... [more ▼]

The Rogaland Anorthosite Province comprises three major massif-type anorthosites, two smaller-sized anorthositic-leuconoritic bodies, as well as a large layered, dominantly noritic intrusion. A mangero-noritic intrusion is found in the northeastern part of the province and major acidic intrusions are located to the far southeast. The Rogaland Anorthosite Province was emplaced into the Sveconorwegian orogenic belt of southwest Scandinavia at 931±3 Ma. Emplacement took place at around 5.5 kbar producing a thermal aureole with osumilite and pigeonite isograds and evidence for dehydration melting. The early history of the hosting terrane most likely dates back to Gothian or late Pre-Gothian times and contain evidence for numerous episodes of folding and deformation. Contact metamorphism was superimposed on a crustal volume, which had been exposed to Sveconorwegian granulite facies metamorphism between 1024 and 970 Ma. Deformation patterns, mineral compositional considerations and geothermobarometry imply that the Rogaland anorthosites crystallized along a P-T trajectory starting at 10-13 kbar, and were emplaced in a mushy state. The possibility that primitive jotunites may be parental to the andesine anorthosites have recently been substantiated, and experimental data show that these jotunites most likely formed by melting of gabbronoritic sources in the lower crust. The 230 km2 Bjerkreim-Sokndal Layered Intrusion also derive from jotunitic parents, and jotunites form a continuous liquid line of descent filling the gap between basic and acidic rocks in Rogaland. This intrusion contains a >7000 m thick layered cumulate sequence, consisting of virtually all the rock types belonging to the anorthosite kindred. The intrusion morphology, layering and compositional variation result from a variety of magma chamber processes, which are discussed in detail. The Rogaland Anorthosite Province also hosts numerous Fe-Ti oxide deposits of variable size, grade and composition. The oxide deposits have been divided into three basic types based on their oxide-phosphate association; type 1: ilmenite-only, type 2: ilmenite + magnetite and type 3: ilmenite + magnetite + apatite. This excursion guide provides detailed itineraries to most parts of the Rogaland Anorthosite Province, with in-depth descriptions of more than 40 key localities, The itineraries cover the various anorthosites, the Bjerkreim-Sokndal Layered Intrusion, jotunitic and acidic intrusions, the hosting metamorphic complex, as well as Fe-Ti oxide and sulfide deposits. [less ▲]

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See detailOptimising a cascade of hydroelectric power stations with the WOLF package
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Brebbia, C. A. (Ed.) Water Ressources Management (2003)

Original free-surface flow solvers have been developed by the HACH during the last years. The resulting fully integrated WOLF package allows engineers to study a very wide range of free surface flows ... [more ▼]

Original free-surface flow solvers have been developed by the HACH during the last years. The resulting fully integrated WOLF package allows engineers to study a very wide range of free surface flows situations. Successful and accurate computations are performed for phenomena as various as hydrological run-offs and dam breaking in quasi 3 dimensions including solid transport effects, as well as rivers networks modelling with explicit exchanges between river paths. All the models, physically based, use efficient and original numerical methods to solve continuous or discontinuous free-surface flow equations. They handle structured or unstructured grids with both first and second order accurate explicit or implicit algorithms in time and space. WOLF also includes powerful user-friendly pre- and post-processing with 2D and 3D animated visualizations as well as a parameters optimization software interconnected with all the package components and based on the innovating method of genetic algorithms. In this paper, the production of the hydroelectric power plants installed on a 60 km long section of the rivers Amblève and Warche in Belgium is presented in details to illustrate the numerical calculation and optimization process. The river network is modeled using real natural topographic data. Hydrological balance is closed and roughness coefficients are calibrated from water level and discharge field measurements. Hydroelectric production is optimized by an automatic calibration of the parameters of the hydrogram injected in the network from the Robertville dam. This approach leads to a substantial gain in both hydroelectric production and financial benefits and deals with all management and security criteria. [less ▲]

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See detailQuasi 2D-numerical model of aerated flow over stepped chutes
André, Stéphanie; Dewals, Benjamin ULg; Pirotton, Michel ULg et al

in Proc. 30th IAHR Congress (2003)

Aerated flow over stepped chutes is principally studied on laboratory models. Consequently, the obtained design relations have a limited field of application. In order to propose a more general ... [more ▼]

Aerated flow over stepped chutes is principally studied on laboratory models. Consequently, the obtained design relations have a limited field of application. In order to propose a more general description of the flow, a quasi-2D numerical model is developed. The fluid is considered as an air-water mixture governed by the shallow-water equations. Moreover, a transport equation for air concentration represents the self-aeration of the flow and a coefficient of uneven vertical velocity distribution integrates indirectly the turbulent structures. The paper includes a brief description of the flow behaviour, the quasi-2D model equations, and a comparison of the numerical results with the measured flow characteristics in a 30° stepped flume. [less ▲]

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See detailLifting, Superadditivity, Mixed Integer Rounding and Single Node Flow Sets Revisited
Louveaux, Quentin ULg; Wolsey, Laurence A.

in 4OR : Quarterly Journal of the Belgian, French and Italian Operations Research Societies (2003), 1

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure combining mixed integer rounding with lifting for the ... [more ▼]

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure combining mixed integer rounding with lifting for the development of strong valid inequalities for knapsack and single node flow sets. Our hope is that the latter can be used in practice to generate cutting planes for mixed integer programs. The survey contains essentially two parts. In the first we present lifting in a very general way, empha- sizing superadditive lifting which allows one to lift simultaneously different sets of variables. In the second, our procedure for generating strong valid inequalities consists of reduction to a knapsack set with a single continuous variable, construc- tion of a mixed integer rounding inequality, and superadditive lifting. It is applied to several generalizations of the 0-1 single node flow set. [less ▲]

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See detailPhotoabsorption Spectroscopy at medium Resolution. The C2HXYZ (XYZ= H, F, Cl and/or Br) Molecules.
Locht, Robert ULg; Leyh, Bernard ULg; Jochims, H.-W. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H - on CD-ROM (2003)

The V-UV photoabsorption spectra of 1,1-C2H2F2, C2HBrF2 and C2HClF2 have been recorded by using synchrotron radiation and are reported.

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See detailApplication of a damage model to an aluminium alloy
Castagne, Sylvie; Habraken, Anne ULg; Cescotto, Serge ULg

in International Journal of Damage Mechanics (2003), 12(1), 5-30

An energy-based isotropic elastoplastic model coupled to damage is implemented in the finite element code LAGAMINE developed for more than fifteen years in the MSM department. In this model, based on the ... [more ▼]

An energy-based isotropic elastoplastic model coupled to damage is implemented in the finite element code LAGAMINE developed for more than fifteen years in the MSM department. In this model, based on the local approach of ductile fracture, effective stresses associated to damage variables are introduced. The damage law allows a continuous description of crack appearance. After a brief description of the model, its identification and its validation for an aluminum alloy are presented. Finally, the research of a global rupture criterion associated to this model is introduced. [less ▲]

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See detailA new formulation of internal forces for non-linear hypoelastic constitutive models verifying conservation laws
Noels, Ludovic ULg; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg et al

in Bathe, K. J. (Ed.) Second MIT Conference on Fluid and Solid Mechanics (2003)

This paper proposes a new formulation of the internal forces for hypoelastic constitutive models ensuring that the elastic work of deformation can be restored by the scheme. Moreover, we demonstrate that ... [more ▼]

This paper proposes a new formulation of the internal forces for hypoelastic constitutive models ensuring that the elastic work of deformation can be restored by the scheme. Moreover, we demonstrate that the work of the plastic deformation is positive and consistent with the material model. [less ▲]

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See detailDevelopment of a Mesoscopic Cell Modeling the Damage Process in Steel at Elevated Temperature
Castagne, Sylvie; Remy, M.; Habraken, Anne ULg

in Key Engineering Materials [=KEM] (2003), 233-236

An on going project whose goal is the development and identification of a mathematical model of steel at elevated temperature using a mesoscopic approach is presented. The research aims to study the ... [more ▼]

An on going project whose goal is the development and identification of a mathematical model of steel at elevated temperature using a mesoscopic approach is presented. The research aims to study the damage process at elevated temperature using information from the macroscopic and mesoscopic scales. As a final application our results will be used to study the industrial process of continuous casting of low carbon steel. [less ▲]

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See detailClinching joining system: validation of numerical models
Pietrapertosa, C.; Zhang, Lihong ULg; Habraken, Anne ULg et al

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

The clinching process, also known as “press joining”, is a mechanical joining technique for sheet metal. Its basic principle is to clamp together several metal sheets by an impact extrusion between a ... [more ▼]

The clinching process, also known as “press joining”, is a mechanical joining technique for sheet metal. Its basic principle is to clamp together several metal sheets by an impact extrusion between a punch and a die. The joint is formed by a localized cold plastic deformation. Forming is used as a joining method. Within the context of this research, University of Liège is developing numerical models, with the FEM code LAGAMINE, that simulate the clinching process. On the other hand, shear tests on simple joints with one or two clinches were realized and their behaviour is reproduced numerically with LAGAMINE. This work opens the way to the analytical formulation of the behaviour of clinched joints. The article will focus on comparisons between experiments and numerical simulations. First, the identification of model parameters will be explained. Then, the predicted failure modes will be analysed by comparison with the xperiments. [less ▲]

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See detailManaging Pests : consumers and commitments: The case of apple and pear growers in Belgium's Lower Meuse Region
Collet, Eric; Mormont, Marc ULg

in Environment & Planning A (2003), 35(3), 413-427

The authors analyse the construction of a seed fruit market. The conventional market had led to the 'anonymousness' of the fruit and to disconnected temporalities. The process needs new types of ... [more ▼]

The authors analyse the construction of a seed fruit market. The conventional market had led to the 'anonymousness' of the fruit and to disconnected temporalities. The process needs new types of coordination and components within the common information channels and actors' network. It also needs the construction of a new contract between producers and consumers, that the conventional market is unable to allow. Producers are experimenting with direct contact with the final consumer to find ways of allowing it. The fruit is replaced in the subject's experience of the final consumer and in the grower's story. The grower's story deals with managing pests, consumers, and commitments through a harmless action: eating a pear or an apple. [less ▲]

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See detailLa sous-traitance internationale : questions choisies
Wautelet, Patrick ULg

in Commisison droit et vie des affaires (Ed.) La sous-traitance (2003)

In this paper, a general overview is given of the legal problems arising in the context of cross-border subcontracting operations. Particular attention is paid to the difficulties arising out of the fact ... [more ▼]

In this paper, a general overview is given of the legal problems arising in the context of cross-border subcontracting operations. Particular attention is paid to the difficulties arising out of the fact that the sub-contracting agreement is intertwined with the main contracting agreement [less ▲]

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See detailNumerical shear tests for different elasto-plastic laws
de Montleau, P.; Duchene, Laurent ULg; Flores, Paulo et al

in Onate, E.; Owen, D. R. J. (Eds.) Proceedings of the VII International Conference on Computational Plasticity (COMPLAS 2003) (2003)

This paper presents the numerical simulation of a cyclic simple shear test. The blank tested is a high strength steel sheet for which we use three different constitutive plastic laws derived from Teodosiu ... [more ▼]

This paper presents the numerical simulation of a cyclic simple shear test. The blank tested is a high strength steel sheet for which we use three different constitutive plastic laws derived from Teodosiu's model. These laws take into account respectively isotropic, kinematic and mixed isotropic-kinematic hardening. The goal of the paper is to provide a first numerical idea of the stress-strain path in the center of an experimental test sample. [less ▲]

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See detailUne méthode générique pour la classification automatique d'images à partir des pixels
Marée, Raphaël ULg; Geurts, Pierre ULg; Wehenkel, Louis ULg

in Revue des Nouvelles Technologies de l'Information (2003), 1

Dans cet article, nous évaluons une approche générique de classification automatique d'images. Elle repose sur une méthode d'apprentissage récente qui construit des ensembles d'arbres de décision par ... [more ▼]

Dans cet article, nous évaluons une approche générique de classification automatique d'images. Elle repose sur une méthode d'apprentissage récente qui construit des ensembles d'arbres de décision par sélection aléatoire des tests directement sur les valeurs basiques des pixels. Nous proposons une variante, également générique, qui réalise une augmentation fictive de la taille des échantillons par extraction et classification de sous-fenêtres des images. Ces deux approches sont évaluées et comparées sur quatre bases de données publiques de problèmes courants: la reconnaissance de chiffres manuscrits, de visages, d'objets 3D et de textures. [less ▲]

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See detailUnimolecular Dissociation of Halogenobenzene Cations by Phase space Theory.
Gridelet, E.; Lorquet, Jean-Claude ULg; Locht, Robert ULg et al

in Anton, J.; Cedrequist, H.; Larsson, M. (Eds.) et al 23rd International Conference on Photonic, Electronic and Atomic Collisions: Book of Abstracts. (2003)

The Orbiting Transition State version of the Phase Space Theory (PST) is used to calculate the KER distributions in the dissociation channel of X (X=I,Cl,Br)-loss from C6H5X+. The results are compared to ... [more ▼]

The Orbiting Transition State version of the Phase Space Theory (PST) is used to calculate the KER distributions in the dissociation channel of X (X=I,Cl,Br)-loss from C6H5X+. The results are compared to the experimental distribution and to that obtained by PST. [less ▲]

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See detailHow ergodic is the Fragmentation of the Pyridine Cation ? A Maximum Entropy Ananlysis
Gridelet, E.; Locht, Robert ULg; Lorquet, Andrée ULg et al

in Anton, J.; Cederquist, H.; Larsson, M. (Eds.) et al 23rd International Conference on the Photonic, Electronic and Atomic Collisions: Book of Abstracts. (2003)

The experimental KER and the statistical distributions are compared by the Maximum Entropy Method. An Ergodicity Index F(E) is defined to measure the phase space sampling efficiency. This is applied to ... [more ▼]

The experimental KER and the statistical distributions are compared by the Maximum Entropy Method. An Ergodicity Index F(E) is defined to measure the phase space sampling efficiency. This is applied to the KERD of C4H4+ cation produced by the C5H5N+ -> HCN+C4H4+ fragmentation path. In this particular case the F(E) is found to decrease steadily with increasing internal energy. [less ▲]

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See detailAlgorithmes de contournement de barrières
Briquet, Cyril ULg

Master of advanced studies dissertation (2003)

GIS (Geographical Information Systems) bring an ever increasing range of solutions to decision makers seeking ever more accurate situational awareness in the issues they are facing. In particular, a GIS ... [more ▼]

GIS (Geographical Information Systems) bring an ever increasing range of solutions to decision makers seeking ever more accurate situational awareness in the issues they are facing. In particular, a GIS can provide a broad range of visual information resulting from computations that may be complex. These require to develop and implement efficient algorithms because of the massive amount of computations or data that are induced by the geographical nature of the processed data. The Urban and Rural Planning and Study Lab of University of Liege seeks to compute accessibility profiles for so-called "slow transport modes" in the Walloon Region. In this context, a relevant issue of computation of a socio-economical index based on spatial and population data is considered. The objective of this work is to modelize a problem of computation accessibility index, then solve it. The central part consists of the developement of a consistent and efficient algorithm chain to compute optimal shortest paths in geographical zones by avoiding barriers. The integration of the involved algorithms as well as the exploitation of intermediary results are fundemental aspects of the proposed solution. Two variants of the problem are modelized: DLOSP (Discrete Line-Of-Sight Paths, that does not take barriers into account) and DGSP (Discrete Geodesic Shortest Paths, that takes barriers into account). The detection and indexation of the barrieres, the refitting of the considered search space, the optimization of visibility requests and the computation of shortest paths constitute the main steps of the proposed algorithm chain. A distributed computing setup, naturally stemming from the structure of the problem itself, is briefly presented. [less ▲]

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See detailLa possible modification de la procédure de révision de la Constitution belge
Behrendt, Christian ULg

in Revue Française de Droit Constitutionnel (2003)

The article examines the question whether it is appropriate to alter the current amendment procedure of the Belgian constitution. Furthermore, the articles enquires into the possible design of a new ... [more ▼]

The article examines the question whether it is appropriate to alter the current amendment procedure of the Belgian constitution. Furthermore, the articles enquires into the possible design of a new amendment procedure. [less ▲]

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