References of "Pirard, Jean-Paul"
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See detailCharacterization of hyperporous polyurethane-based gels by non-intrusive mercury porosimetry
Pirard, René ULg; Rigacci, Arnaud; Marechal, Jacqueline ULg et al

in Polymer (2003), 44(17), 4881-4887

Evaporative drying of polyurethane-based gels produces xerogels. Supercritical drying after replacement of interstitial liquid by supercritical CO2 produces aerogels. SEM micrographs show that both ... [more ▼]

Evaporative drying of polyurethane-based gels produces xerogels. Supercritical drying after replacement of interstitial liquid by supercritical CO2 produces aerogels. SEM micrographs show that both materials are made up of small size particles gathered up in filament-shaped, strongly cross-linked aggregates. Density measurements show that they both have a large pore volume. When submitted to mercury porosimetry, the behavior of these materials is similar to that of inorganic aerogels, as previously observed. Mercury does not penetrate the pore network, but the whole material is densified. The usual Washburn equation cannot be used to analyze the mercury porosimetry. A well-suited equation based on a buckling model of filament-shaped aggregates has been developed in order to determine the pore volume distribution of mineral dried gels. This equation is also valid for analyzing the texture of organic hyperporous materials like polyurethane dried nanoporous gel. (C) 2003 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailMultiscale texture characterization of wastewater sludges dried in a convective rig
Léonard, Angélique ULg; Blacher, Silvia ULg; Pirard, René ULg et al

in Drying Technology (2003), 21(8), 1507-1526

Secondary sludges from two different wastewater treatment plants are conditioned and dewatered in the same way before drying in a lab-scale convective rig at the same operating conditions. Several ... [more ▼]

Secondary sludges from two different wastewater treatment plants are conditioned and dewatered in the same way before drying in a lab-scale convective rig at the same operating conditions. Several techniques are used to characterize the texture of the dried materials over a wide range of scales from nm up to mm. Texture and porosity of the dried products are studied by SEM imaging, nitrogen absorption isotherms (0.5 < d(p) < 50 nm), mercury porosimetry (7.5 nm < d(p) < 150 mum) and X-ray microtomography (spatial resolution= 41 mum). The image analysis of cross-sections reconstructed by microtomography also allows following shrinkage and textural evolution during drying. [less ▲]

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See detailImage analysis characterization of multi-walled carbon nanotubes
Gommes, Cédric ULg; Blacher, Silvia ULg; Masenelli-Varlot, Karine et al

in Carbon (2003), 41(13), 2561-2572

An original image analysis method is presented to characterize multi-walled carbon nanotubes from transmission electron microscopy images. The analysis is performed in three steps: (i) image preprocessing ... [more ▼]

An original image analysis method is presented to characterize multi-walled carbon nanotubes from transmission electron microscopy images. The analysis is performed in three steps: (i) image preprocessing in order to isolate the nanotubes from the background, (ii) image segmentation, aiming at keeping only the measurable sections of nanotubes, and finally (iii) tube characteristics measurement. The measurement is based on a Lambert-like electron absorption law and is performed on the original gray level image itself. Two geometrical and one physical characteristics are determined for each tube, namely, its outer and inner radius and a linear electron absorption coefficient. The method is illustrated by comparing a pristine and an annealed carbon nanotube samples. The compaction of the tube walls during annealing is shown to result from a lowering of the external radius while the inner radius is left unchanged. (C) 2003 Elsevier Ltd. All rights reserved. [less ▲]

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See detailSpectroscopic characterisation of Pd/SiO2 sol-gel prepared catalysts
Beketov, Gennadiy; Heinrichs, Benoît ULg; Lambert, Stéphanie ULg et al

Poster (2003)

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See detailFe/SiO2 sol-gel catalysts synthesised from various iron complexes for N2O decomposition and C3H6 oxidation by N2O
Heinrichs, Benoît ULg; Maxim, Nicolae; Abbenhuis, Hendrikus C L et al

Poster (2003)

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See detailPreparation and characterization of xerogel catalyst microspheres
Alié, Christelle ULg; Ferauche, Fabrice; Heinrichs, Benoît ULg et al

Conference (2003)

For easier handling and use in fixed bed reactors, Pd-Ag/SiO2 aerogel-like xerogel catalysts were shaped into microspheres using the microencapsulation process developed by BRACE GmbH. Before the bead ... [more ▼]

For easier handling and use in fixed bed reactors, Pd-Ag/SiO2 aerogel-like xerogel catalysts were shaped into microspheres using the microencapsulation process developed by BRACE GmbH. Before the bead production process, the xerogel catalyst was ground in water and mixed with ethylene glycol and sodium alginate, the latter of which is the gelation agent. The beads were formed at a vibrating nozzle and solidified during their fall in a water tank containing calcium ions, which induce cross-linking of the alginate and consequent bead hardening. Preliminary work was done using a syringe instead of the material-consuming BRACE unit. The beads were made from a suspension of dried only, dried and calcined, or dried, calcined, and reduced catalyst. The textural properties of the beads were analyzed by nitrogen adsorption-desorption isotherms and mercury porosimetry; and bead catalytic activity was tested for selective hydrodechlorination of 1,2-dichloroethane. The beads made from a suspension of dried catalyst appear to have properties the closest to that of the xerogel reference catalyst. Porosity and surface area are maintained at their level before bead formation. However conversion of 1,2-dichloroethane decreases after the production process, possibly due to poisoning by calcium ions. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailIs it possible to obtain a coherent image of the texture of porous materials?
Noville, Francis; Gommes, Cédric ULg; Pirard, Jean-Paul ULg et al

Poster (2002, December)

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See detailCharacterization of multi-walled carbon nanotubes by image analysis
Gommes, Cédric ULg; Bossuot, Christophe ULg; Pirard, Jean-Paul ULg

Scientific conference (2002, October)

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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

Poster (2002, September 09)

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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 CD-ROM of full texts of the 15th International Congress on Chemical and Process Engineering, CHISA 2002 (Paper P1.24, 9 p.) (2002, August 25)

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

Conference (2002, May)

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See detailMulti-walled nanotubes diameter distribution by image analysis
Gommes, Cédric ULg; BLACHER, Silvia ULg; Bossuot, Christophe ULg et al

Scientific conference (2002, February)

Detailed reference viewed: 14 (1 ULg)