References of "Scientific congresses and symposiums"
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See detailThe Aral Sea: Selected Bibliography
Nihoul, Jacques ULg; Kosarev, A.; Kostianoy, A. et al

Conference (2003, May 05)

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See detailAnomalous 14N/15N ratio in comets 122P/1995 S1 (de Vico) and 153P/2002 C1 (Ikeya-Zhang)
Arpigny, Claude ULg; Cochran, A. L.; Jehin, Emmanuel ULg et al

in Bulletin of the American Astronomical Society (2003, May 01), 35

High-resolution (R 60,000) spectra of the Halley-type comet 122P/1995 S1 de Vico (Period 74 years) and the ``intermediate-period" comet 153P/2002 C1 Ikeya-Zhang (P 370 yr) were obtained with the 2DCoude ... [more ▼]

High-resolution (R 60,000) spectra of the Halley-type comet 122P/1995 S1 de Vico (Period 74 years) and the ``intermediate-period" comet 153P/2002 C1 Ikeya-Zhang (P 370 yr) were obtained with the 2DCoude spectrograph at the 2.7-m Harlan J. Smith telescope of the McDonald Observatory. These comets were within 1 AU from the Sun (0.66 and 0.92 AU, respectively). The spectra display CN (0,0) bands indicating an anomalous [SUP]14[/SUP]N/[SUP]15[/SUP]N isotope ratio, in the sense that it is close to half the value in Earth's atmosphere (the so-called ``Solar system value") and about half that obtained in comet Hale-Bopp from sub-millimeter measurements on HCN, generally believed to be the main parent of CN. Similar conclusions had been reached for C/1995 O1 (Hale-Bopp), an ``old long-period", and for C/2000 WM1 (LINEAR), a ``young long-period" comet. As suggested by Arpigny et al. (2003), this apparent abundance anomaly points towards the existence of other unknown parent(s) of CN, with an even higher [SUP]15[/SUP]N excess. Organic compounds like those found in interplanetary dust particles (IDPs) are good candidates. The similarity between comets of different dynamical ages is pointed out. 1 Research Director FNRS (Belgium) 2 Research Associate FNRS (Belgium) [less ▲]

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See detailLarge-Scale Structures in OB Supergiants: from an Inhomogeneous Surface to a Structured Wind
Morel, Thierry ULg; Marchenko, S. V.; Pati, A. K. et al

in Bulletin of the American Astronomical Society (2003, May 01)

In 2000-2001 we performed long-term spectroscopic monitoring of a sample of bright OB-supergiants aimed at establishing the incidence of co-rotating, large-scale wind structures. In the optical, this can ... [more ▼]

In 2000-2001 we performed long-term spectroscopic monitoring of a sample of bright OB-supergiants aimed at establishing the incidence of co-rotating, large-scale wind structures. In the optical, this can be achieved by detecting rotationally modulated variability in Hα . Practically all the surveyed stars show dramatic line-profile variations operating on a daily (and in some cases on a hourly) timescale. Here we discuss the case of HD 14134 (B3 Ia) where a periodic modulation seen in the optical continuum (stellar surface, P=12.825d) triggers spectacular variations in the Hα emission line (stellar wind). [less ▲]

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See detailEstimation of fructose, glucose and sucrose released by inulin hydrolysis during food processing.
Chevalier, Jean-Paul; Paquot, Michel; Fougnies, C. et al

Poster (2003, May)

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See detailFormasup : un troisième cycle en pédagogie universitaire qui met en oeuvre 7 clés méthodologiques au service du déploiement de pratiques de qualités en EAD
Poumay, Marianne ULg

in Comité d'Edition des Actes de l'Université de Sherbrooke (Ed.) Actes du 20e Congrès de l'Association Internationale de Pédagogie Universitaire (AIPU) - L'Université au service de l'apprentissage : à quelles conditions ? (2003, May)

Bien qu’elles aient à affronter plusieurs défis (regroupement en pôles, nécessité de collaborer de façon interinstitutionnelle et d’adapter contenus et méthodes aux besoins changeants de la société), les ... [more ▼]

Bien qu’elles aient à affronter plusieurs défis (regroupement en pôles, nécessité de collaborer de façon interinstitutionnelle et d’adapter contenus et méthodes aux besoins changeants de la société), les universités offrent peu de formation continuée à leurs enseignants. À l’Université de Liège, cette formation continuée était jusqu’à l’année dernière surtout centrée sur des maîtrises d’outils techniques ou encore de la gestion. Une seconde motivation, tout aussi importante que la première, était le déploiement d’une masse critique de cours en ligne de qualité dans nos instituts d’enseignement supérieur. Pour ces principales raisons, le LabSET a souhaité insuffler à la formation pédagogique des professeurs un renouveau en contenus et méthodes, sous forme d’un curriculum respectant sept principes actifs (sélection des candidats au travers d’appels à projets ; enseignement isomorphe; approche par projets ; accompagnement étroit ; place centrale au concept d’activité des participants ; variété des méthodes et des ressources ; adaptation de l’évaluation aux groupes d’adultes). Ces 7 clés sont illustrées par des exemples pratiques issus du curriculum et des activités vécues, la difficulté résidant dans l’application et le respect de ces principes au quotidien. [less ▲]

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See detailCoupling GIS with database for hydrogeological mapping.
Bouezmarni, Mohamed ULg

Conference (2003, May)

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See detailIdentification of elastoplastic model in large deformation problems
Jeunechamps, Pierre-Paul ULg; Walmag, Jérôme ULg; Delhez, Eric ULg et al

in Cinquini, Carlo (Ed.) Proceedings of the 5th World Congress of Structural and Multidisciplinary Optimization WCSMO5 (2003, May)

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the ... [more ▼]

This paper reports on preliminary results of parameter identification problems in finite element non-linear analyses such as metal forming simulations. Two approaches are compared. The first one is the classic Levenberg-Marquardt algorithm. The second one is a trust-region algorithm based on a quadratic model. The two algorithms are compared on two cases, one of them being an actual experiment. [less ▲]

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See detailPharmacological evaluation of the thromboxane A2 receptor antagonist BM-613
Hanson, Julien ULg; Rolin, S.; De Leval, X. et al

Poster (2003, May)

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See detailAir-sea CO2 fluxes in the Southern Ocean inferred from satellite data
Boutin, J.; Rangama, Y.; Etcheto, J. et al

Poster (2003, May)

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See detailPharmacophore generation to design new leads for selective cyclooxygenase-2 (COX-2) inhibition
Michaux, C.; De Leval, X.; Julemont, F. et al

Poster (2003, May)

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See detailCardiac gated pinhole SPECT in living rat: filtered backprojection versus iterative reconstruction.
Vanhove, Christian; Franken, Philippe R.; Lahoutte, Tony et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (2003, May), 44(5), 276-277

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See detailPyridinic sulfonamides as potential COX-2 inhibitors
Julemont, F.; De Leval, X.; Damas, J. et al

Poster (2003, May)

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See detailMatériaux en céramique SiC/SiC pour paliers lisses sous oxygène liquide: études expérimentales
Bozet, Jean-Luc ULg; Nélis, Marc; Leuchs, M.

Conference (2003, May)

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See detailIn vitro pre-digestion to estimate fermentability of feedstuffs in pig large intestine
Boudry, Christelle ULg; Estrada, Fernando; Schoeling, Olivia et al

in Ball, Ronald O. (Ed.) Proceedings of the 9th International Symposium on Digestive Physiology in Pigs (2003, May)

The aim of this study was to compare ileal and faecal digestibilities to gas production in syringes, preceded or not by an in vitro enzymatic digestion of two pig diets containing different amounts of non ... [more ▼]

The aim of this study was to compare ileal and faecal digestibilities to gas production in syringes, preceded or not by an in vitro enzymatic digestion of two pig diets containing different amounts of non starch polysaccharides (NSP). In vivo, only nitrogen faecal digestibility differed between the two diets. Their enzymatic pre-digestion led to a higher gas production after 16 h of incubation in syringes for the diet with the lowest N faecel digestibility but not without pre-digestion. We may conclude that an in vitro pre-digestion before incubation in syringes is necessary to evaluate feed fermentescibility in pig large intestine. [less ▲]

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See detailStudy of a model low-fat salad dressing formulated with inulin.
Blecker, Christophe ULg; Marti, J.; Chevalier, Jean-Paul et al

Poster (2003, May)

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See detailContribution to the optimization of closed-loop multibody systems : application to parallel manipulators
Collard, Jean-François; Fisette, Paul; Duysinx, Pierre ULg

in Proceedings of the 5th World Congress of Structural and Multidisciplinary Optimization WCSMO5 (2003, May)

This paper describes an original and robust method to optimize the design of closed-loop mechanisms, especially parallel manipulators. In other words, these mechanisms include assembling constraints we ... [more ▼]

This paper describes an original and robust method to optimize the design of closed-loop mechanisms, especially parallel manipulators. In other words, these mechanisms include assembling constraints we solved using a Newton-Raphson algorithm which may fail when the Jacobian matrix of the constraints is ill-conditioned. Therefore, the technique we propose takes advantage of that conditioning to penalize properly the objective function. Applications are shown: on the one hand, a simple example about the design of a planar ejector and, on the other hand, more realistic examples about the kinematical properties of parallel robots, in particular Delta-type and HexaSlide-type manipulators. [less ▲]

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See detailLutte biologique en Afrique du Nord
Jijakli, Haissam ULg

Conference (2003, May)

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See detailGlobal water and salt budget of the Aral Sea from 1960 to 1991.
Sirjacobs, Damien ULg; Grégoire, Marilaure ULg; Delhez, Eric ULg et al

Conference (2003, May)

Focusing on the global water and salt budget of the Aral sea from 1960 till 1991, a compilation of data available in the litterature is analysed with simple models and compared to the measured evolution ... [more ▼]

Focusing on the global water and salt budget of the Aral sea from 1960 till 1991, a compilation of data available in the litterature is analysed with simple models and compared to the measured evolution of the sea. [less ▲]

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See detailRuthenium alkylidenes: a new class of catalysts for Kharasch addition and controlled radical polymerisation of vinyl monomers
Delfosse, Sébastien; Richel, Aurore ULg; Peters, Christelle et al

Poster (2003, May)

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See detailCaractérisation et utilisation du micro-habitat du saumon atlantique (Salmo salar) selon la stucture turbulente del'écoulement.
Brown, Julie; Boyer, Claudine; Enders, Eva et al

Conference (2003, May)

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See detailSynthèse et évaluation biologique de nouvelles coumarines en tant qu’anticoagulants potentiels
Pochet, L.; Rolin, S.; Morel, M. et al

Poster (2003, May)

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See detailWhat binds together virtual teams? Some answers from three case studies
Rorive, Brigitte; Xhauflair, Virginie ULg

Conference (2003, May)

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See detailRespiratory catastrophes during anaesthesia: bronchospasm
Brichant, Jean-François ULg

Conference (2003, May)

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See detailSynthèse et évaluation pharmacologique de N-pyridinyl-alkanesulfonamides apparentés au nimésulide
Julemont, F.; De Leval, X.; Michaux, C. et al

Poster (2003, May)

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See detailAirborne hyperspectral potential for coastal biogeochemistry of the Scheldt estuary and plume
Shimoni, Michal; Sirjacobs, Damien ULg; Borges, Alberto ULg et al

Conference (2003, May)

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See detailApplications de l'approche bayésienne à la représentation des pluies mensuelles africaines par la loi des fuites.
Bernier, Jacques; Parent, Eric; Boreux, Jean-Jacques ULg

Conference (2003, May)

Ce texte présente une analyse bayésienne d'un processus ponctuel marqué particulier (la loi des fuites) avec application à des problèmes de modélisation environnementale hydrométéorologique sur les ... [more ▼]

Ce texte présente une analyse bayésienne d'un processus ponctuel marqué particulier (la loi des fuites) avec application à des problèmes de modélisation environnementale hydrométéorologique sur les données africaines de Ghezala (Tunisie) et Ataktamé (Togo). [less ▲]

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See detailSalt budget and salt composition for the Aral Sea
Konovalov, S.; Belokopitov, V.; Ivanov, L. et al

Poster (2003, May)

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See detailWhat don’t we know about dying and dead seas ?
Sirjacobs, Damien ULg; Nihoul, Jacques ULg

Conference (2003, May)

As conclusions of this NATO Advanced Research Workshop on Dying and Dead Seas, numerous questions remains concerning the various studied water bodies, all along their hydrological cycle and along their ... [more ▼]

As conclusions of this NATO Advanced Research Workshop on Dying and Dead Seas, numerous questions remains concerning the various studied water bodies, all along their hydrological cycle and along their anthropic perturbations. A synthesis of most important open questions is presented. [less ▲]

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See detailNew Solutions to the Problem of Range Dependence in Bistatic STAP Radars
Lapierre, Fabian; Van Droogenbroeck, Marc ULg; Verly, Jacques ULg

in IEEE Radar Conference 2003, Proceedings (2003, May)

We address the problem of detecting slow-moving <br />targets using a space-time adaptive processing (STAP) radar. <br />The construction of optimum weights at each range implies <br />the estimation of ... [more ▼]

We address the problem of detecting slow-moving <br />targets using a space-time adaptive processing (STAP) radar. <br />The construction of optimum weights at each range implies <br />the estimation of the clutter covariance matrix. This is typically <br />done by straight averaging of neighboring data snapshots. <br />However, in bistatic configurations, these snapshots are rangedependent. <br />As a result, straight averaging results in poor performance. <br />After reviewing existing methods for handling the <br />range-dependence, we present new methods exploiting the precise <br />shape of the bistatic direction-Doppler curves. [less ▲]

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See detailSynthesis and pharmacological evaluation of BM-613, an original thromboxane A2 antagonist
Hanson, Julien ULg; Rolin, S.; De Leval, X. et al

Poster (2003, May)

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See detailStudy by sum-frequency generation spectroscopy of a model biosensor : the biocytin-avidin complex
Sartenaer, Yannick; Dreesen, Laurent ULg; Mani, Alaa Adin et al

Poster (2003, May)

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See detailIsolation of bacteriocin-producing lactic acid bacteria from fermented fish product in Senegal.
Dortu, C.; Roblain, D.; Totte, A. et al

Poster (2003, May)

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See detailNew ruthenium catalysts bearing N-heterocyclic carbene ligands for ATRP
Sauvage, Xavier ULg; Richel, Aurore ULg; Delfosse, Sébastien et al

Poster (2003, May)

Stable nucleophilic N-heterocyclic carbenes (NHCs) are neutral, two-electron ligands with a negligible p-back-bonding tendency. They behave as phosphine mimics, yet they are better s- donors and they form ... [more ▼]

Stable nucleophilic N-heterocyclic carbenes (NHCs) are neutral, two-electron ligands with a negligible p-back-bonding tendency. They behave as phosphine mimics, yet they are better s- donors and they form stronger bonds to metal centers than most phosphines. Their electronic and steric properties are liable to ample modification simply by varying the substituents on the nitrogen atoms. Therefore, NHCs constitute a promising new class of ligands available for catalyst engineering and fine-tuning. We found that the 18-electron complex RuCl2(p-cymene)(PCy3) was a versatile and efficient promoter for ring-opening metathesis polymerization of both strained and low-strain cyclic olefins when activated by a suitable precursor such as trimethylsilyldiazomethane. This complex was also an excellent catalyst for ATRP (Atom Transfer Radical Polymerization) of MMA and styrene. In this poster, we present preliminary results obtained in olefin metathesis and in radical reactions (ATRP and Kharasch addition) when tricyclohexylphosphine was substituted by an N-heterocylic carbene ligand. [less ▲]

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See detailDual activity of ruthenium catalysts in controlled radical reactions and olefin metathesis
Delaude, Lionel ULg; Filmon, Karine; Delfosse, Sébastien et al

Conference (2003, May)

The catalytic activity of five ruthenium-arene complexes of the RuCl2(p-cymene)L type was investigated in controlled radical reactions and olefin metathesis. The ligands L were stable Nheterocyclic ... [more ▼]

The catalytic activity of five ruthenium-arene complexes of the RuCl2(p-cymene)L type was investigated in controlled radical reactions and olefin metathesis. The ligands L were stable Nheterocyclic carbenes (NHCs) derived from imidazol-2-ylidene. They differed by the nature of the substituents on the nitrogen atoms (R1) and on the carbon-carbon double bond (R2) of the heterocyclic ring. Thus, R1 was either the mesityl or the cyclohexyl group, and R2 included methyl, hydrogen, or chloro substituents.The complexes were tested as initiators for the Atom Transfer Radical Addition (ATRA) of carbon tetrachloride to methyl methacrylate and styrene, for the Atom Transfer Radical Polymerization (ATRP) of methyl methacrylate and styrene, and for the Ring-Opening Metathesis Polymerization (ROMP) of cyclooctene. Some species displayed a dual activity and promoted both olefin metathesis and ATRP. [less ▲]

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See detailStimuli-responsive core-shell-corona micelles in water
Willet, Nicolas ULg; Lei, Liangcai; Gohy, Jean-François et al

Conference (2003, May)

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See detailDetermination of uncertainty in a liquid chromatographic method for erythromycin from Interlaboratory study results
Dehouck, Pieter; Vander Heyden, Yvan; Smeyers-Verbecke, Johanna et al

Conference (2003, May)

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See detailRuthenium alkylidenes: a new class of catalysts for Kharasch addition and controlled radical polymerisation of vinyl monomers
Delfosse, Sébastien; Richel, Aurore ULg; Demonceau, Albert ULg et al

Poster (2003, May)

Air-stable and readily available ruthenium benzylidene complexes of the general type (RuCl2 (=CHPh)(L)(L')) (L, L' = P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) constitute a new class of catalyst ... [more ▼]

Air-stable and readily available ruthenium benzylidene complexes of the general type (RuCl2 (=CHPh)(L)(L')) (L, L' = P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) constitute a new class of catalyst precursors for atom transfer radical addition (ATRA, also called Kharasch addition) and atom transfer radical polymerisation (ATRP) of methyl methacrylate and styrene, and provide an unprecedented example for the involvement of ruthenium alkylidenes in radical reactions. They promote the addition of carbon tetrachloride to methyl methacrylate and styrene in moderate to high yield (Table 1). They also promote the polymerisation of methyl methacrylate and styrene in a controlled way with good to excellent yields (Table 2). The ligands L (P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) play a particularly important role in determining the rate of the polymerisation. A similarly pronounced influence is exerted by the substituents on the N-heterocyclic carbene. Our results indicate that: 􀀀 The catalysts decompose quickly under ATRA and ATRP conditions; 􀀀 Polymerisations are mediated by both (RuCl2(=CHPh)(L)(L')) complexes and ruthenium species bereft of the benzylidene moiety. [less ▲]

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See detailSevere inhibition of choroidal neovascularization in mice with a combined deficiency of MMP-2 and MMP-9 genes
Lambert, Vincent ULg; Wielockx, B.; Munaut, Carine ULg et al

in Investigative Ophthalmology & Visual Science (2003, May), 44(Suppl. 2), 410

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See detailSynthèse de b-cyclodextrines modifiées
Bertolla, Carine; Piette, Marie ULg; Evrard, Brigitte ULg et al

Poster (2003, May)

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See detailHow to minimise production costs at the preliminary design stage - scantling optimization
Rigo, Philippe ULg

in IMDC’2003, Eighth International Marine Design Conference, Grèce,Vol2 (2003, May)

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See detailModelling of an air condenser working in critical zone for engine cooling by refrigerant loop
Cuevas, Cristian; Winandy, Eric; Lebrun, Jean et al

in 6th Edition of Vehicle Thermal Management Systems (VTMS) Conference (2003, May)

A general and simple model of a condenser for engine cooling by refrigeration loop is presented. The model assumes that the condenser is divided into three distinct zones on the refrigerant side: the ... [more ▼]

A general and simple model of a condenser for engine cooling by refrigeration loop is presented. The model assumes that the condenser is divided into three distinct zones on the refrigerant side: the vapor superheated zone, the two-phase zone and the sub-cooled liquid zone. The model inputs are the dry bulb air supply temperature, the air mass flow rate, the refrigerant supply over-heating, the sub-cooling and the refrigerant mass flow rate. The model is able to give mainly the pressure and temperature in each zone and, of course also, the heat flow and the exhaust enthalpy. The model gives also the geometrical repartition or area percentage of each zone. Adjustable coefficients are used with each correlation to fit the experimental results. An example of identification and validation is presented. The condenser has been tested up to 40 bar with R134a and the model accuracy is within ±2K in condensing temperature prediction. [less ▲]

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See detailStudy of complex carbides obtained after solidification and thermal treatment in High Speed Steels
Tchuindjang, Jérôme Tchoufack ULg; Lecomte-Beckers, Jacqueline ULg

in Proceedings des journées annuelles de la Société belge de physique SBP-BSP (27 et 28 mai 2003) (2003, May)

High-speed steels (HSS) rolls are used in front finishing stands of hot strip mills. Good wear resistance and hardness at high temperature are defining characteristics of HSS. Many carbides are present in ... [more ▼]

High-speed steels (HSS) rolls are used in front finishing stands of hot strip mills. Good wear resistance and hardness at high temperature are defining characteristics of HSS. Many carbides are present in these alloys, each having different effects upon the final properties of HSS. As a result, the nature, the morphology and the amount of these carbides are factors of important concern. Optical microscopy combined with electron microscopy lead to quicker identification and characterization of HSS carbides. [less ▲]

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See detailComputational environment for the design of flexible mechanisms with feedback control
Bruls, Olivier ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

in Proceeding of 6th National Congress on theorical and Applied Mechanics (2003, May)

In this article, numerical methods are exploited for the design of mechatronic systems. A method is presented for the simulation of a flexible mechanism subject to the action of a digital control system ... [more ▼]

In this article, numerical methods are exploited for the design of mechatronic systems. A method is presented for the simulation of a flexible mechanism subject to the action of a digital control system. In the context of model-based control, reduction techniques of mechanical models are also discussed. [less ▲]

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See detailLeast Cost Optimisation of a Medium Capacity Gas Carrier
Rigo, Philippe ULg; Toderan, C.

in COMPIT’03, 2nd Int. EuroConference on Computer and IT Applications in the Maritime Industries,Hamburg, Ed. V. Bertram, 14-17 May 2003 (2003, May)

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See detailOne phase rural distribution installation with direct connection to HV trunk line
Lilien, Jean-Louis ULg; Monfils, Pierre-André; Omboua, Alphonse

in 17th International Conference on Electricity Distribution - CIRED (2003, May)

One original application of the distribution network development, based on existing HV network, is presented for the rural electrification of developing countries. Supply of a few kVA to remote site needs ... [more ▼]

One original application of the distribution network development, based on existing HV network, is presented for the rural electrification of developing countries. Supply of a few kVA to remote site needs specific installations. We have developed, installed and experimented one practical application from April 17th, 2002 in Makola (Congo-Brazzaville, 30 km far from Pointe Noire). We have investigated the case where a HV OHL exists in the vicinity of the village. Our application is a one-phase connection to a 220 kV line with a local demand estimated at 50 kVA (about 500 people) in a first step. We have adapted the existing technology of SF6 inductive voltage transformer in order to supply 50 kVA instead of a few VA. The paper will present the problems met during the design of this specific installation compared to classical substation, and the results of first months of use. [less ▲]

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See detailLe col circulaire comme articulation flexible
Merken, Patrick; Debongnie, Jean-François ULg

Conference (2003, May)

Nous présentons un modèle permettant de déterminer les dimensions du col, R et ho, en fonction du matériau, de l'angle de rotation désiré et du nombre de cycles envisagé. Dans le cas du col circulaire ... [more ▼]

Nous présentons un modèle permettant de déterminer les dimensions du col, R et ho, en fonction du matériau, de l'angle de rotation désiré et du nombre de cycles envisagé. Dans le cas du col circulaire, les équations de base de la résistance des matériaux appliquées aux poutres à section variable admettent une solution analytique grâce à un changement de variable judicieux inspiré de la théorie de la lubrification. Pour un rapport entre l'épaisseur de col et son rayon tendant vers zéro, nous pouvons également dériver des formes asymptotiques des équations obtenues. Dans le cas de rapports ho/R moyens, ces résultats doivent être affectés de coefficients correcteurs qui dépendent eux-mêmes du rapport ho/R et que l'on détermine à partir des résultats numériques obtenus par la théorie complète. Ainsi, toutes les propriétés du col peuvent déduites grâce aux équations aux limites et à ces coefficients simples. [less ▲]

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See detailL'exercice du contrôle de gestion en contexte PME : étude comparée des cas français, canadien et belge
Van Caillie, Didier ULg

in Association Francophone de Comptabilité (Ed.) Actes du 23ème Congrès de l'Association Francophone de Comptabilité (2003, May)

This paper compares practices in terms of management control emerging from field researches conducted respectively in France, Canada and Belgium and proposes a global synthetic model describing ... [more ▼]

This paper compares practices in terms of management control emerging from field researches conducted respectively in France, Canada and Belgium and proposes a global synthetic model describing specifcities of these practices. [less ▲]

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See detailInfluence of cyclodextrins on the solubility and the stability of cyproterone acetate
Henry de Hassonville, Sandrine; Dive, Georges ULg; Prosperi, Christelle ULg et al

Conference (2003, May)

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See detailAVPRO-LBR5, an Initial Design Software Suite with Scantling Optimization Capabilities
Goubault, P.; Besnard, N.; Rigo, Philippe ULg

in IMDC’2003, Eighth International Marine Design Conference, Grèce, Edited by A. Papanikolaou (NTUA, Athènes), Vol2, May 2003 (2003, May)

Detailed reference viewed: 28 (0 ULg)
See detailDer Remalusschrein in Stablo: ein anachronistisches Reliquiar?
Van den Bossche, Benoît ULg

Conference (2003, April 26)

Detailed reference viewed: 19 (0 ULg)
Peer Reviewed
See detailMechanisms of VEGF-A regulation by fully active MT1-MMP in Breast Cancer Cells
Sounni, Nor Eddine ULg

Conference (2003, April 25)

Detailed reference viewed: 1 (0 ULg)
See detailDiabète, hypertension artérielle et insuffisance rénale
Krzesinski, Jean-Marie ULg

Conference (2003, April 17)

Detailed reference viewed: 1 (0 ULg)
Full Text
See detailLOVECLIM, a three-dimensional model of the Earth system for investigating long-term climate changes
Driesschaert, E.; Fichefet, T.; Goosse, G. et al

Poster (2003, April 08)

A three-dimensional global model of the Earth system suitable for studying the long-term evolution of climate (LOVECLIM) has been recently developed. This model is made up of a coarse-resolution three ... [more ▼]

A three-dimensional global model of the Earth system suitable for studying the long-term evolution of climate (LOVECLIM) has been recently developed. This model is made up of a coarse-resolution three-dimensional atmosphere-sea-ice-ocean model (ECBILT-CLIO), a dynamical model of the continental biosphere (VECODE), a comprehensive model of the oceanic carbon cycle (LOCH), and a high-resolution thermomechanical model of the Greenland and Antarctic ice sheets (AGISM). The atmospheric component has the big advantage that it has been simplified to a level that makes runs on a multi-century time-scale computationaly feasible, while still being capable of producing results that, on the whole, are comparable to those of atmospheric general circulation models. The performance of the coupled model is evaluated by performing ensemble simulations over the period 1500-2000 and by comparing the model results to available climate reconstructions. In these simulations, the following forcings are taken into consideration : the variations in solar irradiance, the volcanic activity, the anthropogenic emissions of CO2, and the changes in concentration of other greenhouse gases and sulphate aerosols resulting from human activities. In the future, the model will be used to investigate the evolution of climate and sea level over the third millennium. [less ▲]

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See detailAlkenone carbon isotopes during a bloom of Emiliania huxleyi: Effects of CO2 concentration and production
Benthien, Albert; Zondervan, Ingrid; Riebesell, Ulf et al

Poster (2003, April 07)

The carbon isotopic composition of the C37-alkenones has been used in various paleoceanographic studies to estimate the ancient surface water CO2 concentration [CO2aq]. A number of recent culture, field ... [more ▼]

The carbon isotopic composition of the C37-alkenones has been used in various paleoceanographic studies to estimate the ancient surface water CO2 concentration [CO2aq]. A number of recent culture, field and sediment studies, however, indicate that the carbon isotopic fractionation in haptophyte algae is predominantly controlled by physiological processes and environmental factors other than the ambient [CO2aq]. The most prominent factors are algal growth rate, nutrient availability, light intensity, the carbon uptake mechanism (passive/active), and the carbon source (CO2aq/bicarbonate). To what extent these different factors might affect the carbon isotopic signal of alkenones ultimately preserved in the sediment is still under debate. A cause of uncertainty are the individual strenghts and weaknesses of the different methodological approaches. Culture experiments, for example, cannot perfectly recreate the sum of natural growth conditions and physical processes affecting the carbon isotopic signal in the field and its preservation in the sediment. On the other hand, core-top data represent several hundred to a couple of thousand years and therefore only reflect an average. Here, we present the first study testing the effects of [CO2aq] on the alkenone isotopic signal under natural bloom conditions in a semi-closed system. In a series of 9 floating mesocosms in a Norwegian fjord a bloom of Emiliania huxleyi was followed over a three week period. The mesocosms were covered by gas tight domes to adjust and maintain 3 different CO2 partial pressures in the tent atmosphere ranging from pre-industrial (190 ppmv) to year 2100 levels (680 ppmv) as predicted by the IPCC’s report. We found that during the exponential growth phase the isotopic fractionation of alkenones decreased by 5 to 7 per mill and reached a plateau during the stationary phase. During the stationary phase the alkenone content per cell increased from 1-2 pg/cell to 6-8 pg/cell. Between the [CO2aq] treatments we observed an alkenone isotopic difference of only 2 per mill. These results indicate that changes in algal physiology and/or environmental conditions occuring during the course of an algal bloom strongly affect alkenone isotope fractionation. This effect overrides a comparatively small variation in the alkenone isotopic signal due to [CO2aq]. Implications for alkenone isotopic fractionation as a paleo-production or paleo-nutrient proxy will be discussed. [less ▲]

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See detailOn the coupling of primary production and calcification during a field experiment in the northeastern Atlantic
Chou, Lei; Harlay, Jérôme ULg; Roevros, Nathalie et al

Poster (2003, April 06)

The role of calcifying phytoplanktonic organisms in ocean carbon biogeochemistry and in climate change has received increasing attention in the marine community. The quantification of the production of ... [more ▼]

The role of calcifying phytoplanktonic organisms in ocean carbon biogeochemistry and in climate change has received increasing attention in the marine community. The quantification of the production of biogenic calcium carbonate and associated organic matter in the photic zone and of their fate during settling is essential for a better assessment of the oceanic carbon cycle. In the framework of the Belgian global change programme, we conducted a field experiment on board the R/V Belgica in Spring 2002 along the Northern Bay of Biscay margin during successive coccolithophorid Emiliania huxleyi (Ehux) blooms. We aim, in particular, at quantifying the role of calcifying phytoplanktonic organisms in sequestering carbon. With near real-time transmission of remote sensing data during the survey, we were able to track the position and evolution of the various coccolithophore blooms along the shelf break. Bio-optical measurements were performed for modelling purpose and for calibration of the recently launched MERIS Sensor. During the field campaign, special attention was paid to the precise determination of the dissolved inorganic carbon chemistry. Primary production and rate of calcification were measured using C14 incorporation experiments and the organic to inorganic particulate carbon ratio quantified. Phytoplankton speciation was determined by microscopic examination, flow cytometry and HPLC pigment analyses. Zooplankton grazing experiments on phytoplankton were also performed. Suspended particles were characterised by their chemical composition and morphology. Th234 was used to quantify particle residence times and particulate organic carbon fluxes in surface waters. The results indicate significant particle export during the sampling period, with particle residence times in the upper 80 m ranging from 15 to 45 days. In this presentation, we will integrate the results obtained from remote sensing, biooptical investigation, water chemistry and process studies to elucidate the coupling of primary production and calcification during Ehux blooms and its importance in the marine biogeochemical cycle of carbon. [less ▲]

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See detailBiological responses to CO2-related changes in seawater carbonate chemistry during a bloom of Emiliania huxleyi
Zondervan, Ingrid; Aerts, Katrien; Bellerby, Richard et al

Conference (2003, April 06)

Detailed reference viewed: 9 (0 ULg)
See detailCoccolithophorid Emiliania huxleyi to elevated pCO2 under nitrate limitation
Sciandra, Antoine; Harlay, Jérôme ULg; Lefèvre, Dominique et al

Conference (2003, April 06)

The effects of a partial pressure of CO2 (pCO2) increased from 400 to 700 ppm on nitrogen-limited growing cells of the coccolithophore Emiliania huxleyi were studied. Nitrogen limitation was obtained ... [more ▼]

The effects of a partial pressure of CO2 (pCO2) increased from 400 to 700 ppm on nitrogen-limited growing cells of the coccolithophore Emiliania huxleyi were studied. Nitrogen limitation was obtained within NO3-limited continuous cultures renewed at the rate of 0.5 d−1 and submitted to saturating light level. pCO2 was controlled by bubbling CO2-rich or CO2-free air in the cultures. It is shown that the increase of pCO2 has a rapid effect on cell physiology taking place within the 2 cell divisions occurring after the perturbation. Net calcification rate (C) was depressed from approximately 25%, and, as opposed to what has been reported by previous studies on N-replete cultures, net community production (NCP) was depressed in the same proportion. These results therefore suggest that the increase of pCO2 had not noticeable effect on the calcification/photosynthesis ratio (C/P) when cells of E. huxleyi are NO3-limited. [less ▲]

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See detailImpact of elevated pCO2 on optical properties of the coccolithophorid Emiliania huxleyi grown under nitrate limitation
Denis, Michel; Sciandra, Antoine; Harlay, Jérôme ULg et al

Conference (2003, April 06)

Side scatter and red fluorescence properties of the coccolithophore Emiliania huxleyi were investigated when NO3-limited continuous cultures were submitted to a CO2 partial pressure (pCO2) increase from ... [more ▼]

Side scatter and red fluorescence properties of the coccolithophore Emiliania huxleyi were investigated when NO3-limited continuous cultures were submitted to a CO2 partial pressure (pCO2) increase from 400 to 700 ppm. Cultures renewed at the rate of 0.5 d-1 and were submitted to saturating light level. pCO2 was controlled by bubbling CO2-rich or CO2- free air in the cultures. Side scatter of a single cell is considered to reflect not only its overall shape but mainly its inner structure and content through a complex combination of optical properties including absorption, diffusion, refractive index and refraction. Consequently, the cultures of Emiliania huxleyi were monitored by flow cytometry to detect possible changes in its optical properties at the single cell level under the effect of CO2 doubling in the atmospheric phase. The average SD for counting 5 replicates was less than 1.6% over the period of the study. It was 0.1 and 0.2% for fluorescence and side scatter respectively. Considering the possible decalcification induced by the increase of CO2 in the chemostat atmosphere, the maximum variation that can be expected for side scatter is that provided by the coccolith depletion upon acidification of the cell suspension. The acidification induced a large (36%) decrease of the side scatter signal as expected and had no detectable effect on the red fluorescence. To validate the assignment of this change on coccolith dissolution, the same experiment was repeated with a culture of a non-calcifying species, Dunaliella tertiolecta. The acidification of D. tertiolecta suspension induced no detectable change, both on fluorescence and side scatter. During the time of the experiment, the decline of side scatter never approached the potential 36% change observed when coccoliths are fully dissolved. Interestingly, the specific chl a fluorescence of E. huxleyi slightly increased during the period of high CO2 level. At the end of the experiment this increase amounted to 2.8% of the initial signal. The average SD of red fluorescence being 0.1%, this increase must be considered as significant. Furthermore, it progressed linearly with time over the period of observation. However, the experiment did not last enough to know if the fluorescence increase had already reached its maximum value. The acidification experiment supported the use of side scatter as a relevant parameter to trace potential changes in calcification. Since the estimated 25% decrease in calcification induced by the rise in CO2 atmosphere did not result in dramatic changes in side scatter values, we can conclude that the number of coccoliths and the overall shape and granulosity of cells was not significantly affected by this decrease. Changes must have only affected tiny structure details of the coccoliths like those observed on published electron micrographs. The small but significant increase of the fluorescence signal can be considered as a physiological response to the CO2 rise. This suggests a more dynamic photosynthetic process that would result in a higher rate of organic matter production providing that the system is not nutrient limited as in the present situation. [less ▲]

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See detailPrise en charge par le généraliste du patient hypertendu
Krzesinski, Jean-Marie ULg

Conference (2003, April 05)

"Approche pratique du patient cardiaque en médecine générale"

Detailed reference viewed: 1 (0 ULg)
See detailInfections et grossesse
MELIN, Pierrette ULg

Conference (2003, April 04)

Detailed reference viewed: 7 (0 ULg)
Full Text
See detailQuantification of the Carbonate Pump: Case study of an Emiliania huxleyi bloom in the Bay of Biscay
Harlay, Jérôme ULg; Chou, Lei; Roevros, Nathalie et al

Poster (2003, April 03)

Little attention has been paid until now to the processes controlling the production, dissolution and fate of biogenic calcium carbonate in the oceans. It is however well known that net deposition rates ... [more ▼]

Little attention has been paid until now to the processes controlling the production, dissolution and fate of biogenic calcium carbonate in the oceans. It is however well known that net deposition rates of inorganic carbon to the sediments are comparable to those of organic matter. There remains still large uncertainties in the production and redissolution of biogenic carbonate in the marine system and thus about the role of the carbonate pump in response to anthropogenic CO2 perturbations. The understanding of these processes is also a prerequisite to predict the response of marine organisms to global environmental changes. In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophorid blooms occur frequently. The study focuses on processes associated with the oceanic production and dissolution of calcium carbonate, by combining field investigations, laboratory experiments and modelling efforts. Remote sensing demonstrates a close relationship between vertical mixing along the continental margin and the development of the phytoplankton bloom. We will present here, results of 14C incorporation experiments used to evaluate the rate of production of organic and inorganic particulate carbon, obtained during a coccolithophorid spring bloom in the investigated area. A tentative mass balance of the carbon fluxes for this area will be presented, confirming the importance that the calcium carbonate pump may play in the oceanic system. [less ▲]

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Full Text
See detailModelling the hydrodispersive behaviour of variably saturated chalk
Brouyère, Serge ULg

Conference (2003, April 02)

The presentation dscribes the mathematical and numerical modelling of solute tracer experiments in variably saturated chalk

Detailed reference viewed: 9 (0 ULg)
See detailElectron and proton shock aurora observed by IMAGE-FUV
Meurant, M.; Gérard, Jean-Claude ULg; Hubert, Benoît ULg et al

in EGS - AGU - EUG Joint Assembly (2003, April 01)

The FUV instrument on the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite monitors the aurora in three different spectral regions. The Wideband Imaging Camera (WIC) observes the ... [more ▼]

The FUV instrument on the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite monitors the aurora in three different spectral regions. The Wideband Imaging Camera (WIC) observes the molecular N_2 LBH and the atomic NI emissions at 140-180 nm. The two channels of the Spectrographic Imager (SI) observe the Doppler shifted Lyman-α emission at 121.8 nm due to precipitating protons (SI12) and the electron auroral emission of OI at 135.6 nm (SI13). Three simultaneous snapshots are recorded each 2 minutes. In this study, the FUV instrument allows a global viewing of the aurora with a high temporal resolution both in proton and electron. It is used to study the shock aurora resulting from the disturbance caused by the arrival of a coronal mass ejection on the front of the magnetosphere. A comparison between electron and proton injection features at global scale is performed for different isolated events with positive and negative interplanetary B_z. A correlation with IMF and solar wind parameters is presented as well as a description of the magnetosphere morphology given by the Tsyganenko model in the shock aurora period. [less ▲]

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See detailObservation of dayside subauroral proton flashes with IMAGE-FUV.
Hubert, Benoît ULg; Gérard, Jean-Claude ULg; Fuselier, S. A. et al

in EGS - AGU - EUG Joint Assembly (2003, April 01)

The IMAGE-FUV experiment onboard the IMAGE satellite includes three imagers: the WIC and SI13 instruments produce a global scale imaging of the N_2 LBH wavelength range and of the OI 130.4 nm emission ... [more ▼]

The IMAGE-FUV experiment onboard the IMAGE satellite includes three imagers: the WIC and SI13 instruments produce a global scale imaging of the N_2 LBH wavelength range and of the OI 130.4 nm emission respectively, and are thus devoted to the study of the electron aurora. The third imager, SI12, remotely senses the Doppler shifted Lyman-alpha emission, that is solely due to the proton aurora, at the global scale. We present here a new auroral feature observed with the SI12 instrument, consisting of sudden dayside subauroral injections of protons at magnetic latitudes sometimes lower than 60^o MLAT, at the foot of field lines of L shells as low as 4 RE. The extension of the feature in magnetic local time is variable and cases extending from Ë 0700 to Ë 1500 MLT were seen. The relaxation time of these features will be discussed. Most of these dayside subauroral proton flashes are found to be related to sudden solar wind dynamic pressure pulses, but a few counter examples were found. The relationship with the IMF orientation is investigated. [less ▲]

Detailed reference viewed: 6 (1 ULg)
See detailComparison of auroral processes at Jupiter and Saturn
Clarke, J.; Gérard, Jean-Claude ULg

Conference (2003, April 01)

Extensive series of images of Jupiter's aurora have been obtained from HST and ground-based telescopes, while only a handful of images of Saturn's aurora have been taken to date and only with the HST ... [more ▼]

Extensive series of images of Jupiter's aurora have been obtained from HST and ground-based telescopes, while only a handful of images of Saturn's aurora have been taken to date and only with the HST. With the Cassini spacecraft approaching Saturn, it is timely to compare what we know of Saturn's aurora with the better-studied case of Jupiter. This presentation will summarize the basic features of Jupiter's auroral processes, give an overview of what we know about Saturn's auroral processes, and speculate on what might be learned from further studies at the time of Cassini approach to Saturn. [less ▲]

Detailed reference viewed: 10 (1 ULg)
See detailElectron and proton shock aurora observed by IMAGE-FUV
Meurant, M.; Gérard, Jean-Claude ULg; Hubert, Benoît ULg et al

in EGS - AGU - EUG Joint Assembly (2003, April 01)

The FUV instrument on the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite monitors the aurora in three different spectral regions. The Wideband Imaging Camera (WIC) observes the ... [more ▼]

The FUV instrument on the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite monitors the aurora in three different spectral regions. The Wideband Imaging Camera (WIC) observes the molecular N_2 LBH and the atomic NI emissions at 140-180 nm. The two channels of the Spectrographic Imager (SI) observe the Doppler shifted Lyman-α emission at 121.8 nm due to precipitating protons (SI12) and the electron auroral emission of OI at 135.6 nm (SI13). Three simultaneous snapshots are recorded each 2 minutes. In this study, the FUV instrument allows a global viewing of the aurora with a high temporal resolution both in proton and electron. It is used to study the shock aurora resulting from the disturbance caused by the arrival of a coronal mass ejection on the front of the magnetosphere. A comparison between electron and proton injection features at global scale is performed for different isolated events with positive and negative interplanetary B_z. A correlation with IMF and solar wind parameters is presented as well as a description of the magnetosphere morphology given by the Tsyganenko model in the shock aurora period. [less ▲]

Detailed reference viewed: 13 (4 ULg)
See detailA new FUV auroral feature on Jupiter
Grodent, Denis ULg; Gladstone, G. R.; Gérard, Jean-Claude ULg et al

Conference (2003, April 01)

In December 2000, a series of HST/STIS FUV images of Jupiter's north auroral region displayed bright transient spots located near local midnight. In the images taken at CML Ë 220[SUP]o[/SUP] the spots ... [more ▼]

In December 2000, a series of HST/STIS FUV images of Jupiter's north auroral region displayed bright transient spots located near local midnight. In the images taken at CML Ë 220[SUP]o[/SUP] the spots (one or two) appear near the limb, poleward and equatorward of the main auroral oval, at latitude Ë 73[SUP]o[/SUP] and λ[SUB]III[/SUB] longitude Ë 145[SUP]o[/SUP]. The dimensions of each spot are very small, about 1[SUP]o[/SUP] in latitude and 5[SUP]o[/SUP] in longitude, which is about the size of the footprint of the Io satellite. However, the analysis of the position of the Galilean satellites and of known small-bodies (comets, asteroids) shows that these spots are not magnetically associated with any of these objects. The emitted power of the spots is variable and can reach several GW (more than the power emitted at the Io footprint). The lightcurves derived from multiple images are consistent with spots disappearing behind the planetary limb as the planet rotates. In addition, one short time-tagged image undoubtedly shows a bright double--spot feature pulsating with a period of 300 s. According to the VIP4 magnetic model, the auroral spots map along field lines down to the jovian magnetosphere in a small region roughly located near midnight at distances larger than 60~R_J. At these distances, a 1[SUP]o[/SUP] by 5[SUP]o[/SUP] auroral spot subtends an equatorial region smaller than 10~R_J by 10~R_J . Consequently, the auroral spots cannot be directly associated with large scale process involving the whole magnetotail but rather with localized events. [less ▲]

Detailed reference viewed: 8 (3 ULg)
See detailSeasonal effects on the proton auroral precipitation observed by IMAGE-FUV
Coumans, Valérie ULg; Gérard, Jean-Claude ULg; Hubert, Benoît ULg et al

in EGS - AGU - EUG Joint Assembly (2003, April 01)

The statistical approach of the auroral electron precipitation has shown a summer/winter dissymmetry. Electron energy flux in the 1900-0300 MLT sector increases from summer to winter. The frequency of ... [more ▼]

The statistical approach of the auroral electron precipitation has shown a summer/winter dissymmetry. Electron energy flux in the 1900-0300 MLT sector increases from summer to winter. The frequency of occurrence of intense aurora (with electron energy flux above 5 erg cm[SUP]-2[/SUP] s[SUP]-1[/SUP]) in the dusk-to-midnight sector was observed to be 3 times higher under winter conditions (or conditions of local darkness) than under summer conditions (or in sunlight). On board the IMAGE satellite the FUV instruments monitor the aurora in three different spectral regions and especially one of them only images the auroral proton precipitation. The Wideband Imaging Camera (WIC) observes the molecular N_2 LBH and the atomic NI emissions between 140 and 180 nm. The two channels of the Spectrographic Imager (SI) respond to the Doppler shifted Lyman-α emission at 121.8 nm due to precipitating protons (SI12) and the electron auroral emission of OI at 135.6 nm (SI13). The auroral proton and electron energy fluxes are calculated from the IMAGE-FUV data, relying on energy degradation and auroral emission models. We will discuss possible seasonal asymmetry in the auroral proton precipitation. A statistical study is made with FUV data from 2 successive solstices to minimize effects due to the solar activity variations. [less ▲]

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See detailForecast verification using skill scores and wavelets. Application to a two-way nested primitive equation model of the Ligurian Sea.
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Rixen, M. et al

Conference (2003, April)

The verification of a forecast is an important part of a forecasting process. It allows to establish the quality of a model, and to make the pertinent improvements. The verification methodology may be ... [more ▼]

The verification of a forecast is an important part of a forecasting process. It allows to establish the quality of a model, and to make the pertinent improvements. The verification methodology may be designed to detect the errors contained in the model. The verification process consist in the comparison of the model results with a reference system (as sample climatology, or the output of a reference version of the model), in order to establish the accuracy and skill of the first one. The Anomaly Correlation Coefficient, the Brier Skill Score and the Root Mean Square Error are used in the present work to quantify the predictive skill. The disadvantage of this kind of measures is its over simplification. They are very useful, since the comparison between the model and the reference system is reduced to a limited set of numbers to establish the error, but it also results in a great loss of information. The method presented here combines the skill score analysis with a more detailed study. The use of wavelet transforms is shown to be useful, because of their capacity to localize in time and frequency the analysed signal. The signal is decomposed at different spatial scales, where the skill score methods can be applied separately. The information obtained with this method is more detailed, and scales where the largest errors occur can be easily identified. This combination of methods has been applied to a two-way nested primitive equation model of the Ligurian Sea. The scale decomposition allows to better understand the differences between the model and the observed field, to establish the weaknesses and strengths of the model, and to propose the possible improvements that can be done. [less ▲]

Detailed reference viewed: 33 (1 ULg)
See detailIsolement de suppresseurs hétérologues extragéniques multi-copies de la double mutation de levure msb3- msb4-
Delroisse, Jean-Marc; Breban, Martine; Burny, Arsène et al

Poster (2003, April)

Detailed reference viewed: 5 (0 ULg)
See detailSelf consistent and computationally efficient EOF calculation from incomplete oceanographic data sets
Beckers, Jean-Marie ULg; Alvera Azcarate, Aïda ULg; Barth, Alexander ULg et al

Conference (2003, April)

We present a new self-consistent method to infer missing data from oceanographic data series and to extract the relevant empirical orthogonal functions. As a by-product, the new method allows to detect ... [more ▼]

We present a new self-consistent method to infer missing data from oceanographic data series and to extract the relevant empirical orthogonal functions. As a by-product, the new method allows to detect the number of statistically significant EOFs by a cross-validation procedure for a complete or incomplete data set as well as the noise level and interpolation error. Since for the proposed filling and analysis method there is no need for a priori information about the error covariance structure, the method is self-consistent and parameter free. The method is exemplified on a synthetic data set as well as real satellite data with cloud coverage. [less ▲]

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See detailSAFIR. A thermal/structural program modelling structures under fire
Franssen, Jean-Marc ULg

in Proceedings of NASCC 2003 (2003, April)

Detailed reference viewed: 59 (2 ULg)
See detailAssimilation of Sea Surface Temperature in a doubly, two-way nested primitive equation model of the Ligurian Sea
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Rixen, M. et al

Conference (2003, April)

The GHER 3D primitive equation model is implemented with three different resolutions: a low resolution model (1/4^o) covering the whole Mediterranean Sea, an intermediate resolution model (1/20^o) of the ... [more ▼]

The GHER 3D primitive equation model is implemented with three different resolutions: a low resolution model (1/4^o) covering the whole Mediterranean Sea, an intermediate resolution model (1/20^o) of the Liguro-Provençal basin and a high resolution model (1/60^o) simulating the fine mesoscale structures in the Ligurian Sea. Boundary conditions and the averaged fields (feedback) are exchanged between two successive nesting levels. The model of the Ligurian Sea is also coupled with the assimilation package SESAM. It allows to assimilate satellite data and in situ observations using the local adaptative SEEK (Singular Evolutive Extended Kalman) filter. Instead of evolving the error space by the numerically expensive Lyapunov equation, a simplified algebraic equation depending on the misfit between observation and model forecast is used. Starting from the 1st January 1998 the low and intermediate resolution models are spun up for 18 months. The initial conditions for the Ligurian Sea are interpolated from the intermediate resolution model. The three models are then integrated until August 1999. During this period AVHRR Sea Surface Temperature of the Ligurian Sea is assimilated. The results are validated by using CTD and XBT profiles of the SIRENA cruise from the SACLANT Center. The overall objective of this study is pre-operational. It should help to identify limitations and weaknesses of forecasting methods and to suggest improvements of existing operational models. [less ▲]

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Full Text
Peer Reviewed
See detailSolving problems with contact in machining process simulation
Masset, Luc ULg; Debongnie, Jean-François ULg; Berger, Frederic

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

At the 2001 Esaform conference, we have presented a simulation tool designed to predict form errors of part surfaces obtained by face milling and turning processes. The most relevant aspect of the ... [more ▼]

At the 2001 Esaform conference, we have presented a simulation tool designed to predict form errors of part surfaces obtained by face milling and turning processes. The most relevant aspect of the developed method is its ability to solve industrial cases with huge 3D finite element meshes in a very small time. Until recently, we were only considering pure linear problems. However, the simulation of several machining operations requires the introduction of contact. The present paper describes the numerical method developed to solve such non linear problems. [less ▲]

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See detailBiogas (O2, CO2 and DMS) dynamics within and below sea ice during coastal sea ice edge retreat
Delille, Bruno ULg; Delille, D.; Jourdain, B. et al

Conference (2003, April)

Detailed reference viewed: 8 (0 ULg)
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Peer Reviewed
See detailNew methods for handling the range dependence of the clutter spectrum in non-sidelooking monostatic STAP radars
Lapierre, Fabian; Van Droogenbroeck, Marc ULg; Verly, Jacques ULg

in International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2003), Proceedings, Volume 5 (2003, April)

We address the problem of detecting slow-moving targets using a non-sideloking monostatic space-time adaptive processing (STAP) radar. The construction of optimum weights at each range implies the ... [more ▼]

We address the problem of detecting slow-moving targets using a non-sideloking monostatic space-time adaptive processing (STAP) radar. The construction of optimum weights at each range implies the estimation of the clutter covariance matrix. This is typically done by straight averaging of neighboring data snapshots. The range-dependence of these snapshots generally results in poor performance. We present two new methods that handle the rangedependence by exploiting the geometry of the direction-Doppler curves. [less ▲]

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Peer Reviewed
See detailImproved Carotid and Mesenteric Blood Flows with the Use of 21% Oxygen During Resuscitation of Newborn Piglets with Severe Asphyxia
Haase, Erika; Stevens, Jonathan; Rigo, Vincent ULg et al

in Pediatric Research (2003, April), 53(4 Part 2/2), 377

Detailed reference viewed: 23 (7 ULg)
See detailPhytoplankton, bacteria and viruses: sources of CDOM in experimental mesocosms maintained under different pCO2 levels
Rochelle-Newall, E.; Delille, Bruno ULg; Gattuso, J.-P. et al

Poster (2003, April)

Detailed reference viewed: 7 (0 ULg)
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Peer Reviewed
See detailInfluence of the Aral Sea negative water balance on its seasonal circulation and ventilation patterns : use of a 3D hydrodynamic model
Sirjacobs, Damien ULg; Grégoire, Marilaure ULg; Delhez, Eric ULg et al

in Geophysical Research Abstracts (2003, April), 5(09052), 2003509052

Within the context of the EU INCO-COPERNICUS program "Desertification in the Aral Sea Region: A study of the Natural and Anthropogenic Impacts" (Contract IAC2-CT-2000-10023), a large-scale 3D hydrodynamic ... [more ▼]

Within the context of the EU INCO-COPERNICUS program "Desertification in the Aral Sea Region: A study of the Natural and Anthropogenic Impacts" (Contract IAC2-CT-2000-10023), a large-scale 3D hydrodynamic model was adapted to address specifically the macroscale processes affecting the Aral Sea water circulation and ventilation. The particular goal of this research is to simulate the effect of lasting negative water balance on the 3D seasonal circulation, temperature, salinity and water-mixing fields of the Aral Sea. The original Aral Sea seasonal hydrodynamism is simulated with the average seasonal forcings corresponding to the period from 1956 to 1960. This first investigation concerns a period of relative stability of the water balance, before the beginning of the drying process. The consequences of the drying process on the hydrodynamic of the Sea will be studied by comparing this first results with the simulation representing the average situation for the years 1981 to 1985, a very low river flow period. For both simulation periods, the forcing considered are the seasonal fluctuations of wind fields, precipitation, evaporation, river discharge and salinity, cloud cover, air temperature and humidity. The meteorological forcings were adapted to the common optimum one-month temporal resolution of the available data sets. Monthly mean kinetic energy flux and surface tensions were calculated from daily ECMWF wind data. Monthly in situ precipitation, surface air temperature and humidity fields were interpolated from data obtained from the Russian Hydrological and Meteorological Institute. Monthly water discharge and average salinity of the river water were considered for both Amu Darya and Syr Darya river over each simulation periods. The water mass conservation routines allowed the simulation of a changing coastline by taking into account local drying and flooding events of particular grid points. Preliminary barotropic runs were realised (for the 1951-1960 situation, before drying up began) in order to get a first experience of the behaviour of the hydrodynamic model. These first runs provide results about the evolution of the following state variables: elevation of the sea surface, 3D fields of vertical and horizontal flows, 2D fields of average horizontal flows and finally the 3D fields of turbulent kinetic energy. The mean seasonal salinity and temperature fields (in-situ data gathered by the Russian Hydrological and Meteorological Institute) are available for the two simulated periods and will allow a first validation of the hydrodynamic model. Various satellites products were identified, collected and processed in the frame of this research project and will be used for the validation of the model outputs. Seasonal level changes measurements derived from water table change will serve for water balance validation and sea surface temperature for hydrodynamics validation. [less ▲]

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