References of "Pirard, Jean-Paul"
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See detailNew silica based polymeric systems designed for the solid-liquid extraction of uranyl ions
Caprasse, F.; Leroy, Delphine ULg; Martinot, Lucien et al

in Journal of Materials Chemistry (2002), 12(1), 137-142

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See detailSingle step synthesis of metal catalysts supported on porous carbon with controlled texture
Job, Nathalie ULg; Ferauche, fabrice; Pirard, René ULg et al

in Studies in Surface Science and Catalysis (2002), 143

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See detailImage analysis characterization of highly oriented freeze-drying porous materials
Blacher, Silvia ULg; Maquet, Véronique; Jérôme, Robert ULg et al

in Image Analysis and Stereology (2002), 21

Image analysis has been used as a potential tool for the characterization of the texture of ultramacroporous foams prepared by freeze-drying. It has been shown that this technique actually provides ... [more ▼]

Image analysis has been used as a potential tool for the characterization of the texture of ultramacroporous foams prepared by freeze-drying. It has been shown that this technique actually provides valuable information on the structure of this kind of material. Image analysis of SEM micrographs of transverse sections at two different magnifications gave information on both the macroporosity (10 μm < width < 100 μm) and ultramacroporosity (width > 100 μm). Moreover, the foam anisotropy has been determined by image analysis of longitudinal sections. [less ▲]

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See detailCharacterization of porous texture of hyperporous materials by mercury porosimetry using densification equation
Pirard, René ULg; Alié, Christelle ULg; Pirard, Jean-Paul ULg

in Powder Technology (2002), 128(2-3), 242-247

The purpose of this paper is to propose a method of analyzing the mercury porosimetry data in the case of materials called hyperporous. This class of material does not undergo intrusion by mercury ... [more ▼]

The purpose of this paper is to propose a method of analyzing the mercury porosimetry data in the case of materials called hyperporous. This class of material does not undergo intrusion by mercury; instead, it shrinks under the mercury isostatic pressure and its density increases. The phenomenon is partially or completely irreversible. The proposed method enables computing the pore volume distribution as a function of the pore size in the same way as Washburn's method does in the case of mercury intrusion. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailIs it possible to obtain a coherent image of the texture of a porous material?
Noville, Francis ULg; Gommes, Cédric ULg; Doneux, C. et al

in Studies in Surface Science and Catalysis (2002), 144

This study consists in verifying the coherence of a few commonly used analysis methods of nitrogen adsorption-desorption isotherms. These methods were tested on model samples obtained by mechanically ... [more ▼]

This study consists in verifying the coherence of a few commonly used analysis methods of nitrogen adsorption-desorption isotherms. These methods were tested on model samples obtained by mechanically mixing two micro- and mesoporous solids respectively with known, mass proportions. Although the individual analysis methods may lead to discrepancies in the interpretation of the isotherms, their systematic comparison allows drawing a coherent picture of the porous texture. [less ▲]

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See detailAg/SiO2 and Cu/SiO2 cogelled xerogel catalysts for benzene combustion and 2-butanol dehydrogenation
Lambert, Stéphanie ULg; Tcherkassova, Natalia; Cellier, Caroline et al

in Studies in Surface Science and Catalysis (2002), 143

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See detailCharacterisation of silica low-density xerogels in presence of additives by image analysis and nitrogen adsorption-desorption
Blacher, Silvia ULg; Alié, Christelle ULg; Gommes, Cédric ULg et al

in Characterization of Porous Solids VI (2002)

Micro- and mesopore structure modifications in silica low-density xerogels induced by additives in TEOS-based alcogels precursors are discussed on the basis of image analysis of transmission electron ... [more ▼]

Micro- and mesopore structure modifications in silica low-density xerogels induced by additives in TEOS-based alcogels precursors are discussed on the basis of image analysis of transmission electron microscopy (TEM) micrographs and nitrogen adsorption-desorption experiments. To perform image analysis, novel image processing has been developed on the basis of classical signal treatment and mathematical morphology theory. The obtained results have been correlated with classical and fractal interpretation of nitrogen adsorption-desorption measurements. [less ▲]

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See detailSingle step synthesis of metal catalysts supported on porous carbon with controlled texture
Job, Nathalie ULg; Ferauche, Fabrice; Pirard, René ULg et al

in Studies in Surface Science and Catalysis (2002)

This paper presents an original preparation method of metal catalysts supported on carbon porous material [1]. Carbon porous materials can be synthesised by evaporative drying and pyrolysis of aqueous ... [more ▼]

This paper presents an original preparation method of metal catalysts supported on carbon porous material [1]. Carbon porous materials can be synthesised by evaporative drying and pyrolysis of aqueous resorcinol-formaldehyde gels whose operating, variables are correctly chosen. The porous texture of these materials is mainly controlled by the precursor solution pH. Texture analysis shows that it is possible to tailor the morphology of these materials : indeed, micro-macroporous, micro-mesoporous, microporous or non porous materials can be obtained by varying the pH value in a narrow pH interval. This texture control is slightly influenced by the introduction of a metal in the gel : the limits of the pH interval can slightly differ when a metal salt is added to the resorcinol-formaldehyde aqueous solution. Carbon supported nickel and palladium catalysts prepared by this method have proven to be active for ethylene hydrogenation. [less ▲]

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See detailThe role of the main silica precursor and the additive in the preparation, of low-density xerogels
Alié, Christelle ULg; Pirard, René ULg; Pirard, Jean-Paul ULg

in Journal of Non-Crystalline Solids (2002), 311(3), 304-313

The incorporation of an additive during sol-gel synthesis reduces shinkage during ambient drying. The following additives have been studied: 3-,(2-aminoethylamino)propyltrimethoxysilane (EDAS), 3 ... [more ▼]

The incorporation of an additive during sol-gel synthesis reduces shinkage during ambient drying. The following additives have been studied: 3-,(2-aminoethylamino)propyltrimethoxysilane (EDAS), 3-aminopropyltriethoxysilane (AES) and 3-(2-aminoethylamino)propyltriethoxysilane (EDAES) and the main silica precursors were tetraethylorthosilicate (TEOS) and tetrapropylorthosilicate (TPOS). When the additive contains methoxy groups (EDAS), it acts as a nucleation agent of the silica particles and exactly the same properties (pore volume, specific surface area, particle and aggregate size) are obtained whether the main reagent is TEOS or TPOS. The nucleation mechanism is based on the difference in reactivity between additive and main reagent. In case of nucleation by the additive, the nucleation agent fixes the properties whatever the main silica precursor is. When both the additive and the main reagent contain ethoxy groups (series AES-TEOS and EDAES-TEOS), there is no nucleation mechanism by the additive, and the silica particle size remains nearly constant. With less reactive main reagent (series AES-TPOS and EDAES-TPOS), pore volumes up to 17 cm(3)/g have been obtained with pore sizes up to nearly 10 pm and very big particles (similar to100 nm). The absence of nucleation by the additive for the couples AES-TPOS and EDAES-TPOS could be due to the fact that the difference in reactivity between ethoxy groups and propoxy groups is not sufficient to initiate the nucleation mechanism by the additive. In the absence of nucleation by the additive, the main reagent plays a role: highly porous materials with very large p. ores are prepared with TPOS. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailTexture characterization of ultramacroporous materials using non-destructive methods
Blacher, Silvia ULg; Maquet, Véronique; Léonard, Angélique ULg et al

in Studies in Surface Science and Catalysis (2002), 158

Image analysis, impedance spectroscopy and X-ray microtomography have been used as non-destructive methods in order to characterize ultramacroporous materials (pore width > 1 mum). These methods are used ... [more ▼]

Image analysis, impedance spectroscopy and X-ray microtomography have been used as non-destructive methods in order to characterize ultramacroporous materials (pore width > 1 mum). These methods are used to investigate the texture of different kinds of materials, i.e., highly oriented polylactide (PLA) foams prepared by freeze-drying, isotropic polyolefin foams prepared by thermal degradation of a chemical foaming agent and convective heat dried wastewater sludges. The image analysis of SEM micrographs recorded at different magnifications gave information on the pore size distribution and pore morphology. Impedance spectroscopy was used to investigate the transport properties of the three-dimensional porous matrices by measurement of the water ionic conduction. Finally, 3D image reconstruction from 2D cross-sections obtained by X-ray microtomography allowed visualizing the pore structure. [less ▲]

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See detailSynthesis of Pd/SiO2, Ag/SiO2 and Cu/SiO2 catalysts by sol-gel process : study of metal dispersion and nucleation phenomenon
Lambert, Stéphanie ULg; Ferauche, Fabrice; Heinrichs, Benoît ULg et al

in CD-ROM of full abstracts of the 2nd International Conference on Silica Science and Technology, SILICA 2001 (4 p.) (2001, September 03)

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See detailStudy of the sugar ingot flow-patterns in the Notre-Dame Refinery silo in Oreye
Job, Nathalie ULg; Dardenne, A.; Pirard, Jean-Paul ULg

Poster (2001, May 29)

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See detailStudy of the sugar ingot flow-patterns in the Notre-Dame Refinery silo in Oreye
Job, Nathalie ULg; Dardenne, A.; Pirard, Jean-Paul ULg

in Proceedings of the First International Congress on Tracers and Tracing methods (2001)

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See detailMercury porosimetry applied to porous silica materials: successive buckling and intrusion mechanisms
Alié, Christelle ULg; Pirard, René ULg; Pirard, Jean-Paul ULg

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2001), 187

Some silica low-density xerogels exhibit two successive volume variation mechanisms, compaction and intrusion when submitted to mercury porosimetry. The position of the pressure of transition P-t between ... [more ▼]

Some silica low-density xerogels exhibit two successive volume variation mechanisms, compaction and intrusion when submitted to mercury porosimetry. The position of the pressure of transition P-t between the two mechanisms is characteristic of the tested material and allows to compute the buckling constant used to determine the pore size distribution in the compaction part of the experiment. The analysis of the mercury porosimetry data of a low-density xerogel wrapped in a tight membrane by the buckling law (intrusion is prevented and the sample is crushed during the whole porosimetry experiment) leads to a continuous unimodal distribution similar to the distribution of the unwrapped sample obtained by applying the buckling law below P-t and the intrusion law above P-t. This experiment confirms the validity of the use of the buckling law. The behaviour of the low-density xerogels can be related to one of their morphological characteristics. As the size of the aggregates of silica particles increases, the strength towards crushing increases and the change of mechanism from crushing to intrusion takes place at a lower pressure. (C) 2001 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailImage analysis, impedance spectroscopy and mercury porosimetry characterisation of freeze-drying porous materials
Blacher, Silvia ULg; Maquet, Véronique; Pirard, René ULg et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2001), 187-188

Image analysis and impedance spectroscopy have been used as potential tools for the characterization of the texture of ultramacroporous PLA foams prepared by freeze-drying. It has been shown that these ... [more ▼]

Image analysis and impedance spectroscopy have been used as potential tools for the characterization of the texture of ultramacroporous PLA foams prepared by freeze-drying. It has been shown that these two techniques actually provide valuable information on the structure of this material. They are complementary to mercury porosimetry, which does not allow morphological details to be distinguished. Image analysis of SEM micrographs of transverse cross-sections at two different magnifications gave information on both the macroporosity (1 μm < width < 10 μm) and ultramacroporosity (width > 10 μm). Impedance spectroscopy was used to investigate the transport properties of the three-dimensional porous matrices by measurement of ionic conduction [less ▲]

Detailed reference viewed: 49 (8 ULg)