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See detailVers l'élaboration d'un modèle d'ecobilan pour l'évaluation environnementale de l'agriculture au Maroc: Cas du périmètre irrigué du Tadla
Debouche, Charles ULg; Krim, LHassan

in Debouche, Charles; Fagroud, Mustapha; Debbarh, Abdelhafid (Eds.) et al Equilibre Agriculture-Environnement: Enjeux, outils et perspectives du conseil agricole (2003)

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See detailDetuning effects on the mazer
Martin, John ULg; Bastin, Thierry ULg

in Physicalia Magazine (2003), 25

A short review of the theoretical studies of the cold atom micromaser (mazer) is presented. Existing models are then improved by considering more general working conditions. Especially, the mazer physics ... [more ▼]

A short review of the theoretical studies of the cold atom micromaser (mazer) is presented. Existing models are then improved by considering more general working conditions. Especially, the mazer physics is investigated in the situation where a detuning between the cavity mode and the atomic transition frequency is present. Interesting new effects are pointed out. Especially, it is shown that the cavity may slow down or speed up the atoms according to the sign of the detuning and that the induced emission process may be completely blocked by use of a positive detuning. The transmission probability of ultracold atoms through a micromaser is also studied and we generalize previous results established in the resonant case. In particular, it is shown that the velocity selection of cold atoms passing through the micromaser can be very easily tuned and enhanced using a nonresonant field inside the cavity. [less ▲]

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See detailSubstructure Damage Detection by Principal Component Analysis : Application to Environmental Vibration Testing
De Boe, Pascal; Yan, Ai-Min; Golinval, Jean-Claude ULg

Conference given outside the academic context (2003)

This paper deals with the application of statistical process control techniques based on principal component analysis to vibration-based damage diagnosis of structures. It is well known that localized ... [more ▼]

This paper deals with the application of statistical process control techniques based on principal component analysis to vibration-based damage diagnosis of structures. It is well known that localized structural damages with relative small amplitude may not much affect the global modal response of the structure, at least at low frequencies. Nevertheless, it can be expected that the local dynamic behavior of the damaged structural component is significantly affected. By applying principal component analysis on the sensor time responses, it may be shown that any change of a particular sensor will affect the subspace spanned by the response of the complete sensor set. The subspace corresponding to the damaged structure can then be compared with the subspace of an initial state in order to diagnose possible damages. The problem of structural damage detection is addressed in the case of a fatigue test by means of an electro-dynamic shaker. In this example, monitoring of the structural responses is performed during a qualification test in order to detect any structural damage. [less ▲]

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See detailUse of Whole-Field Displacement Measurements for Model Updating of Blades
SIMON, Daniel; Golinval, Jean-Claude ULg

Conference given outside the academic context (2003)

Non-contacting measurement techniques such as modal holographic interferometry look very promising for finite element (F.E.) model updating or error localization of plate-like structures in the field of ... [more ▼]

Non-contacting measurement techniques such as modal holographic interferometry look very promising for finite element (F.E.) model updating or error localization of plate-like structures in the field of structural dynamics. The purpose of this work is to investigate a way to better exploit the high spatial resolution of optical techniques in order to correct FE meshing discretization errors and/or model parameter errors. The key idea developed in this paper is to calculate successively two error estimators using only measurement data. The experimental field is first used for the detection of singular regions corresponding to high deformation (or stress) gradients. This estimator indicates the regions where a mesh refinement is required. Thus a second estimator is calculated and used for parameter error detection. [less ▲]

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See detailModel Updating Based on Frequency Response Functions Using A General Finite Element Code
Yan, Ai-Min; Golinval, Jean-Claude ULg

in European Journal of Mechanical and Environmental Engineering (2003), 48(3), 149-162

Model updating techniques using frequency response function (FRF) data are studied in this paper. The numerical techniques are discussed for implementation with a large commercial finite element (FE ... [more ▼]

Model updating techniques using frequency response function (FRF) data are studied in this paper. The numerical techniques are discussed for implementation with a large commercial finite element (FE ) code. System equivalent reduction expansion process is adopted to reduce the complete FE solutions onto the experimental degrees of freedom. The rank-deficiency difficulty with this method is overcome using either of two numerical techniques: diagonal perturbation and singular value decomposition. This second technique is also used in solving the updating equation. Experimental FRF data are compared with the FE solutions, and the updated model parameters are obtained via an iteration procedure. A simplified frequency domain assurance criterion is proposed to evaluate the correlation between the FE model and the measured structure at the chosen frequencies. After verifying the efficiency of the methods with several benchmark tests, the program is applied to an aeroplane model test. Some conclusions are given and remaining problems illustrated. [less ▲]

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See detailLingopti project: semi-continuous casting process of coper-nickel alloys
Pecquet, Etienne ULg; Pascon, Frédéric ULg; Lecomte-Beckers, Jacqueline ULg et al

in Dick, E.; Vierendeels, J.; Cantrijn, F. (Eds.) et al Proceedings of the 6th national congress on theoretical and applied mechanics (2003)

Lingopti project is a First Europe project. It treats semi-continuous casting of copper-nickel alloys ingots. The research, performed in the University of Liège, consists in the optimisation of the mould ... [more ▼]

Lingopti project is a First Europe project. It treats semi-continuous casting of copper-nickel alloys ingots. The research, performed in the University of Liège, consists in the optimisation of the mould and the whole casting process of the LBP S.A. company (Chênée – Liège) to obtain better cast products. In fact, cast products sometimes present long oscillation marks (λ ≈ 500mm) and some ingots have many internal cracks. The semi-continuous process consists in the vertical casting of 7m height ingots. The goal is also to test different chemical compositions of the material and to predict what happens on the casting process. [less ▲]

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See detailStructural Integrity Monitoring by Vibration Measurements
Yan, Ai-Min; De Boe, Pascal; Golinval, Jean-Claude ULg

Conference given outside the academic context (2003)

This paper presents a comparative study on several approaches of structural dam-age diagnosis based on vibration meas-urements. Stochastic subspace identifica-tion method is used to identify modal pa ... [more ▼]

This paper presents a comparative study on several approaches of structural dam-age diagnosis based on vibration meas-urements. Stochastic subspace identifica-tion method is used to identify modal pa-rameters and to generate a Kalman predic-tion model, which are taken as damage-sensitive features for structural damage detection. A statistical process control technique based on principal component analysis (PCA) is also presented. An im-provement and enhancement of PCA is proposed. It is assumed that without dam-ages, structural responses should remain approximately in a hyperplane defined by the principal directions of data. Damage localization is explored with these meth-ods. As only the measured output signals are needed, the methods are convenient for on-line monitoring. The efficiency and limitation of the proposed methods are illustrated by numerical and practical ap-plications. [less ▲]

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See detailDistinction Between Cultivated And Wild Chicory Gene Pools Using Aflp Markers
Van Cutsem, P.; Du Jardin, Patrick ULg; Boutte, C. et al

in Theoretical & Applied Genetics = Theoretische und Angewandte Genetik (2003), 107(4),

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See detailA model of the seasonal dynamics of biomass and production of the seagrass Posidonia oceanica in the Bay of Calvi (Northwestern Mediterranean)
Elkalay, Khalid; Frangoulis, Constantin; Skliris, Nikolaos ULg et al

in Ecological Modelling (2003), 167(1-2), 1-18

Modelling of seagrasses can be an effective tool to assess factors regulating their growth. Growth and production model of Posidonia oceanica, the dominant submerged aquatic macrophyte occurring in the ... [more ▼]

Modelling of seagrasses can be an effective tool to assess factors regulating their growth. Growth and production model of Posidonia oceanica, the dominant submerged aquatic macrophyte occurring in the Bay of Calvi (Corsica, Ligurian Sea, Northwestern (NW) Mediterranean) was developed. The state variables are the above- and below-ground biomass of P oceanica, the epiphyte biomass, and the internal nitrogen concentration of the whole plant. Light intensity and water temperature are the forcing variables. The model reproduces successfully seasonal growth and production for each variable at various depths (10, 20 and 30 m). The model can simulate also a number of consecutive years. Sensitivity analysis of model's parameters showed that the maximum nitrogen quota n(max) rate is the most sensitive parameter in this model. The results simulations imply that light intensity is one of the most important abiotic factors, the diminution of which can cause an important reduction in seagrass density. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailLes protéines de choc thermique (heat shock proteins). II Les protéines de choc thermique (heat shock proteins). II. Hsp70, biomarqueur, bioprotecteur.
Wirth, Delphine; Gustin, Pascal ULg; Drion, Pierre ULg et al

in Annales de Médecine Vétérinaire (2003), 147(2), 127-144

The exposure of any organism to high temperature induces rapid and transient cellular overexpression of specific proteins, the heat shock proteins (Hsps). This response, called heat shock response, was ... [more ▼]

The exposure of any organism to high temperature induces rapid and transient cellular overexpression of specific proteins, the heat shock proteins (Hsps). This response, called heat shock response, was initially discovered in Drosophila. The genes hsps were among the first eukaryotic genes to be cloned and whose regulation, which involves activation of heat shock factor (HSF), was elucidated. More recently, study of Hsp functions, particularly Hsp70, started. Their protective role, related to their molecular chaperon function, was inferred from experiments showing that Hsp70 expression, induced by a first stress, results in a cellular tolerance to second stress. Better understanding of the heat shock response had led to the development of two search fields on Hsp70 expression : (1) its use as biomarker of cellular stress and (2) the exploitation of its cytoprotective functions against various insults. This review includes historic of the research on the heat shock response, description of regulation mechanism of Hsp70 expression, and the interesting perspectives allocated to Hsp70 as biomarker and therapeutic tool. ----------- L’exposition de tout organisme à des températures élevées induit l'expression cellulaire rapide et transitoire de protéines spécifiques, les protéines de choc thermique (Hsps pour " heat shock proteins "). Cette réponse des cellules au choc thermique ou " heat shock response " a été initialement découverte chez la drosophile. Les gènes hsps furent parmi les premiers gènes eucaryotes à être clonés et utilisés comme paradigme dans l'étude des mécanismes de régulation transcriptionnelle faisant intervenir l'activation d'un ou plusieurs " heat shock factors" (HSFs). C'est plus récemment que l'étude des fonctions des Hsps, particulièrement Hsp70, a débuté. Le rôle protecteur de celle-ci, lié à sa fonction de " chaperon " protéique, a été déduit d'expériences montrant que l'induction de l'expression de Hsp70 lors d'un stress était associée au développement d'une tolérance cellulaire vis-à-vis d'un stress ultérieur. En plus d'un intérêt fondamental pour la compréhension de la "réponse au choc thermique", deux axes de recherche appliquée se sont développés visant à investiguer la possibilité d'utiliser l'expression de Hsp70 comme biomarqueur de souffrance cellulaire d'une part et, d'autre part, d'exploiter ses fonctions comme moyen de protection des cellules contre divers types d'agressions. Cette revue décrit l'historique des découvertes sur la " réponse au choc thermique ", le mécanisme régulant l'expression de Hsp70 ainsi que les perspectives intéressantes s'ouvrant à l'utilisation de l'expression de Hsp70 en tant que biomarqueur et outil thérapeutique. [less ▲]

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See detail« Comment servir le souverain ». A propos d’un traité pseudo-platonicien inédit
Bauden, Frédéric ULg; Ghersetti, Antonella

in Quaderni di Studi Arabi (2003), 20-21

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See detailPhylogeny
Baudoin, Jean-Pierre ULg; Maquet, A.

in Plant and Soil (2003), 252(1), 55-128

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See detailGene flow among wild Phaseolus lunatus L. populations in the Central Valley of Costa Rica
Ouedraogo, M.; Maquet, A.; Baudoin, Jean-Pierre ULg

in Annual Report Bean Improvement Cooperative (2003), 46

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See detailLa société de management
Kohl, Benoît ULg; Herbatschek, M.; Matray, Didier ULg

in Actualités en droit des affaires (2003)

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See detailLe passé récent, la réforme de l'impôt des personnes physiques, le cas des villes
Jurion, Bernard ULg

in Bulletin de Documentation du Ministère des Finances (2003)

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See detailL'application dans le temps de la peine de travail
Jacobs, Ann ULg

in Revue de Droit Pénal et de Criminologie (2003)

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See detailLa motivation du refus de prononcer une peine de travail
Jacobs, Ann ULg

in Revue de Jurisprudence de Liège, Mons et Bruxelles (2003)

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See detailEffects Of The Nature Of Nitrogen Supplementation On Voluntary Intake, Rumen Parameters And Ruminal Degradation Of Dry Matter In Sheep Fed Oat Silage-Based Diets
Mahouachi, Mokhtar; Haddad, L.; Kayouli, Chedly et al

in Small Ruminant Research (2003), 48(3), 181-187

The effects of nature of nitrogen supplementation on silageDMintake (SDMI), totalDMintake (TDMI), rumen parameters and ruminal degradation of DM of silage and wheat straw were studied using four adult ... [more ▼]

The effects of nature of nitrogen supplementation on silageDMintake (SDMI), totalDMintake (TDMI), rumen parameters and ruminal degradation of DM of silage and wheat straw were studied using four adult Noire de Thibar rams. Silage was made from predominantly oats harvested at milk stage and ensiled without preservative. The silage was offered ad libitum as the sole diet (OS) or supplemented with 450 g DM of iso-nitrogen (25.6 g/kg DM) and iso-energy (0.8 Unité Fourragère Lait: UFL/kg DM) concentrate containing soybean meal (SBM), urea (UR) or poultry litter (PL) as nitrogen supplements. SDMI (g/kgW0.75 × day) and TDMI (g/kgW0.75 × day) were affected (P < 0.001) by the type of supplement and averaged 63.9, 60.1, 54.9, 51.1 and 63.9, 81.4, 74.8, 72.2 for OS, SBM, PL and UR diets, respectively. In comparison with other diets, SBM diet systematically decreased (P < 0.05) the pH of the rumen after the morning feeding and reduced the rumen concentration of total VFA at 1 h after feeding. SBM diet decreased DM disappearance of the oat silage incubated in nylon bags for 72 h (P < 0.05), but not of wheat straw. The three supplements increased the ammonia-N concentrations in the rumen for several hours after feeding in comparison with the OS diet. However, only the SBM diet kept this difference just before the next meal. It is concluded that despite its low nutritive value (0.62 UFL and 108 g crude protein/kg DM), the oat silage is well consumed by the local ruminants accustomed to use poor forages for a long time. In Tunisia, poultry litter may be used as a nitrogen source to supplement the oat silage for sheep. [less ▲]

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