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See detailDefinition and Classification of Power System Stability
Kundur, Prabha; Paserba, John; Ajjarapu, Venkat et al

in IEEE Transactions on Power Systems (2004), 19(2), 1387-1401

The problem of defining and classifying power system stability has been addressed by several previous CIGRE and IEEE Task Force reports. These earlier efforts, however, do not completely reflect current ... [more ▼]

The problem of defining and classifying power system stability has been addressed by several previous CIGRE and IEEE Task Force reports. These earlier efforts, however, do not completely reflect current industry needs, experiences and understanding. In particular, the definitions are not precise and the classifications do not encompass all practical instability scenarios. This report developed by a Task Force, set up jointly by the CIGRE Study Committee 38 and the IEEE Power System Dynamic Performance Committee, addresses the issue of stability definition and classification in power systems from a fundamental viewpoint and closely examines the practical ramifications. The report aims to define power system stability more precisely, provide a systematic basis for its classification, and discuss linkages to related issues such as power system reliability and security. [less ▲]

Detailed reference viewed: 821 (10 ULg)
See detailDéfinition d'index de risque dans l'infarctus myocardique
Chapelle, Jean-Paul ULg

Conference (1982, May 28)

Detailed reference viewed: 7 (0 ULg)
See detailDéfinition d’indices successionnels pour la caractérisation de la dynamique post-culturale
Bangirinama, F; Bigendako, M J; Lejoly, J et al

Poster (2010)

Detailed reference viewed: 24 (2 ULg)
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See detailDéfinition d’indices successionnels pour la caractérisation de la dynamique post-culturale.
Bangirinama, F; Bigendako, M J; Lejoly, J et al

in Bois et Forêts des Tropiques (2010), 305(3), 57-66

Detailed reference viewed: 15 (1 ULg)
See detailDéfinition d’indices successionnels pour la caractérisation de la dynamique post-culturale.
Bangirinama, F; Bigendako, M J; Lejoly, J et al

in Vololoniaina, H J; Razafimandimbison, S G; De Block, P (Eds.) XIXth AETFAT Congress- Madagascar (2010)

Detailed reference viewed: 23 (3 ULg)
See detailDéfinition d'un système de financement de l'hôpital de jour gériatrique (Health Services Research)
Gillain, Daniel ULg; Velghe, Anja; Boman, Xavier et al

Report (2008)

Detailed reference viewed: 221 (15 ULg)
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See detailDéfinition de bases biologiques et éco-hydrauliques pour la libre circulation des poissons dans les cours d'eau non navigables de Wallonie. Volume 3: Identification des priorités d'action d'après les critères biologiques et piscicoles.
Ovidio, Michaël ULg; Philippart, Jean-Claude ULg

Report (2007)

Depuis 1988, le Ministère de la Région wallonne (MRW), Direction Générale des Ressources Naturelles et de l'Environnement (DGRNE), Direction des Cours d'Eau non navigables (DCENN) fait procéder à un ... [more ▼]

Depuis 1988, le Ministère de la Région wallonne (MRW), Direction Générale des Ressources Naturelles et de l'Environnement (DGRNE), Direction des Cours d'Eau non navigables (DCENN) fait procéder à un inventaire complet des obstacles physiques potentiels à la libre circulation des poissons dans les cours d'eau des bassins hydrographiques de la Meuse, du Rhin et partiellement de l'Escaut. Cette mission est assurée par une équipe de la Fédération des Sociétés de Pêche de l'Est et du Sud de la Belgique (FSPESB) qui a déjà couvert un vaste domaine hydrogéographique . Complémentairement à cet inventaire sur le terrain, la DCENN a chargé le LDPH-ULg de réaliser des études visant à caractériser, notamment par biotélémétrie, la franchissabilité effective de divers types d'obstacles, d'évaluer l'efficacité de certaines échelles à poissons construites sur des cours d'eau non navigables et, de manière générale, de rassembler un maximum d'informations sur l'évolution des connaissances et des techniques en matière de rétablissement de la libre circulation des poissons en rivière (Ovidio et al., 2005 & 2007). Ces différentes approches centrées sur les cours d'eau non navigables sont aussi développées par le LDPH sur les cours d'eau navigables à travers le suivi scientifique du programme Saumon Meuse (MRW, 2007) et l'exécution du volet ULg du programme Fédéral 2003-2006 FISHGUARD (Blust et De Boeck, 2003 ; De Boeck et al., 2006). L’approche du problème de la libre circulation des poissons en rivière se situe dans un contexte régional (Nouveau Code wallon de l'Eau),mais aussi international : Décision Benelux d'avril 1996 (Benelux, 1996-1999), Plans d'Action Meuse de la Commission Internationale de la Meuse-CIM (CIM, 2001 et 2002), Implications de la Directive Cadre sur l'Eau quant à la qualité écologique des eaux de surface (Guyon et al., 2006), Perspective de plans d’actions pour le sauvetage de l’anguille européenne (Belpaire, 2005). Vu l'état actuel d'avancement de toutes les études et actions menées en Région wallonne en cette matière, nous proposons dans le présent dossier de synthèse une analyse des options de gestion applicables aux espèces de poissons les plus concernées de notre ichtyofaune ainsi qu'une sélection des aménagements à évaluer en vue d’une amélioration et/ou à réaliser en priorité en fonction de différents critères. [less ▲]

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See detailDéfinition de propriétés acido-basiques dans les liquides ioniques de seconde génération
Robert, Thierry ULg

Doctoral thesis (2013)

The ionic liquids are salts having the particularity of being molten at temperatures lower than 100 °C. Consequently, these new solvents mainly made up of ions have original physicochemical properties ... [more ▼]

The ionic liquids are salts having the particularity of being molten at temperatures lower than 100 °C. Consequently, these new solvents mainly made up of ions have original physicochemical properties. Within a few years, the ionic liquids passed from a laboratory curiosity to a true field of research impossible to circumvent, currently in full rise. Indeed, the replacement of usual organic solvents in catalytic and/or separation processes by these neoteric solvents offers many advantages but also new opportunities for the “Green Chemistry”. However, the systematic exploitation of the ionic liquids as reactional media rests in particular on the understanding of their chemical properties, which for some of them are still scarcely known, such as the acidity for example. This thesis thus aims to undertake a study of the acido-basic properties of (and in) these solvents, and more particularly to determine the accessible levels of acidity for acid solutions (with added HOTf or HNTf2) in second generation ionic liquids such as [HNEt3][NTf2], [BMIm][NTf2], [BHIm][NTf2], [BMIm][BF4], [BMIm][OTf], [BMIm][PF6] and [BMIm][SbF6]. In order to evaluate these acidity levels, we propose two different methods, each one resting on an extra-thermodynamic assumption. The first, the Hammett acidity function H0, is based on the protonation equilibrium of indicators whose pKa's are proposed as solvent independent. The second, the Strehlow potentiometric function R0(H+), consists in measuring, in a given solvent, the electrochemical potential of the proton compared to the ferricinium/ferrocene redox couple whose potential is supposed to be independent of the solvent, and then to refer it versus the Normal Hydrogen Electrode (NHE) in water. The two methods lead to the same conclusions. Firstly, the ionic liquids are generally contaminated by residual basic impurities (from solvents needed for the synthesis…) which need to be neutralized before reaching the acidity characteristic of the medium. The levels of acidity then obtained are very high and can reach values as high as R00(H+) = -10 in the case of [BMIm][BF4]. Then, the accessible level of acidity in an ionic liquid depends mainly on the nature of its anion, and not of that of its cation. We thus obtain the following classification, by decreasing acidity: [PF6-] > [BF4-] > [NTf2-] > [OTf-], indicating that the triflate is the more solvating anion It was found however that the Hammett acidity function led, for the same concentration in acid, to different levels of acidity, depending on the indicator used. The ionic liquids would consequently be media less dissociating than estimated in the literature and the Hammett function would then be related to an apparent acidity (H0)app, underestimating the real acidity. Finally, a difference in acidity between HNTf2 and HOTf is observed in [BMIm][NTf2] and [BMIm][OTf], HNTf2 showing an acidic character stronger than HOTf. On the other hand, in [BMIm][OTf] these two acids show the same acidity since that of HNTf2 has been leveled by solvent. [less ▲]

Detailed reference viewed: 175 (32 ULg)
See detailDéfinition des conditions de référence biologiques des rivières en Wallonie
Fauville, Claude; Darchambeau, François ULg; Gosselain, Véronique et al

Report (2004)

Detailed reference viewed: 22 (0 ULg)