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See detailDétermination des propriétés de couches dans le béton à l'aide d'un géoradar commercial à hautes fréquences: approche pic-à-pic et analyse fréquentielle du coefficient de réflexion
Van der Wielen, Audrey ULg; Nguyen, Frédéric ULg; Courard, Luc ULg

in Annales du Bâtiment et des Travaux Publics (2014)

The Ground Penetrating Radar (GPR) is an efficient tool for the non-destructive inspection of concrete structures. It is widely used for the detection of rebars or humid zones or for evaluating the ... [more ▼]

The Ground Penetrating Radar (GPR) is an efficient tool for the non-destructive inspection of concrete structures. It is widely used for the detection of rebars or humid zones or for evaluating the thickness of elements. But when an element contains a thin layer, the radar waves are submitted to multiple reflections on the interfaces and the layer appears in the radargram as a single reflection, whose detailed analysis can allow determining the thickness and the permittivity of the thin layer. Two approaches were considered in this paper. In the first one, the analysis is based on the peak-to-peak reflection amplitude. The second approach uses a frequency analysis of the reflection coefficient, whose amplitude and phase can then be calculated for several frequencies. With this method, the thickness and permittivity of the layer can in theory be simultaneously determined. Both methods were numerically validated through finite difference simulations and experimentally tested on concrete samples containing an air layer of variable thickness. We showed that the frequency analysis allowed to reach a higher precision in the parameters estimation for a limited additional computing cost. The method efficiency depends on the conditions and is optimal for layers with a high permittivity presenting a large contrast with the matrix. [less ▲]

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See detailDétermination des propriétés de couches minces dans le béton à l’aide d’un géoradar commercial à hautes fréquences: approche pic-à-pic et analyse fréquentielle du coefficient de réflexion
Van der Wielen, Audrey; Courard, Luc ULg; Nguyen, Frédéric ULg

in Balayssac, Jean-Paul (Ed.) Compte-rendus de Diagnobeton 2014 (2014)

The Ground Penetrating Radar (GPR) is an efficient tool for the non-destructive inspection of concrete structures. It is widely used for the detection of rebars or humid zones or for evaluating the ... [more ▼]

The Ground Penetrating Radar (GPR) is an efficient tool for the non-destructive inspection of concrete structures. It is widely used for the detection of rebars or humid zones or for evaluating the thickness of elements. But when an element contains a thin layer, the radar waves are submitted to multiple reflections on the interfaces and the layer appears in the radargram as a single reflection, whose detailed analysis can allow determining the thickness and the permittivity of the thin layer. Two approaches were considered in this paper. In the first one, the analysis is based on the peak-to-peak reflection amplitude. The second approach uses a frequency analysis of the reflection coefficient, whose amplitude and phase can then be calculated for several frequencies. With this method, the thickness and permittivity of the layer can in theory be simultaneously determined. Both methods were numerically validated through finite difference simulations and experimentally tested on concrete samples containing an air layer of variable thickness. We showed that the frequency analysis allowed to reach a higher precision in the parameters estimation for a limited additional computing cost. The method efficiency depends on the conditions and is optimal for layers with a high permittivity presenting a large contrast with the matrix. [less ▲]

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See detailDétermination des puissances spécifiques critiques dans des rivières à charge de fond caillouteuse
Petit, François ULg; Perpinien, G.; Deroanne, Claude ULg

in Revue Géographique de l'Est (2000)

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See detailDétermination des zones de prévention du site de captage d'Onoz
Henrion, Vincent; Dassargues, Alain ULg

Report (2005)

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See detailDétermination du besoin en méthionine du taurillon Blanc Bleu Belge culard en finition.
Froidmont, Eric; Beckers, Yves ULg; Thewis, André ULg

in 6èmes Rencontres autour de la Recherche sur les Ruminants, Paris, France, 1-2 décembre 1999 (1999)

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See detailDétermination du besoin en méthionine du taurilon Blanc Bleu Belge culard en croissance.
Froidmont, Eric; Beckers, Yves ULg; Thewis, André ULg

in Rencontres Recherches Ruminants. (1998)

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See detailDétermination du carbone et de l'hydrogène dans les schistes houillers : Contribution à l'étude de la formation de la houille
Spring, Walthère ULg

in Annales de la Société Géologique de Belgique. Mémoires (1887), XIV

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See detailDétermination du débit à pleins bords et de sa récurrence dans différentes rivières de Moyenne et de Haute Belgique
Petit, François ULg; Daxhelet, C.

in Bulletin de la Société Géographique de Liège (1989)

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See detailLa détermination du débit de filtration glomérulaire. Aspects biologiques
CAVALIER, Etienne ULg

Conference (2015, March 05)

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See detailDétermination du degré de réticulation du collagène par sa solubilité thermique et par analyse calorimétrique différentielle (ACD).
Bastiaens, Annette; Sindic, Marianne ULg; Deroanne, Claude et al

in Viandes et Produits Carnés (1990), 11

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See detailDetermination du profil en acides gras du lait par spectroscopie moyen infrarouge.
Dehareng, Frédéric; Soyeurt, Hélène ULg; Veselko, Didier et al

in 14 emes Recontres autour des recherches sur les ruminants, Paris, les 5et 6 Decembre 2007 (2007, December 01)

Detailed reference viewed: 107 (8 ULg)