References of "Pirard, Jean-Paul"
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See detailSilo flow-pattern diagnosis using the tracer method
Job, Nathalie ULg; Dardenne, Albert; Pirard, Jean-Paul ULg

in Journal of Food Engineering (2009), 91(1), 118-125

The storage silo of a sugar refinery was designed by its manufacturer for a plug-flow pattern of sugar ingots in order to ensure effective drying of the sugar introduced at the top of the silo. Because of ... [more ▼]

The storage silo of a sugar refinery was designed by its manufacturer for a plug-flow pattern of sugar ingots in order to ensure effective drying of the sugar introduced at the top of the silo. Because of the excessive moisture content of the extracted ingots, the quality of flow within the silo was called into question. The silo flow-pattern was thus studied by introducing sugar lumps as a tracer at the top of the silo filled with ingots. The tracer weight percentage was measured at the outlet. Results show that the silo flow-pattern is not of the plug-flow type in its whole volume: after formation of a crater, only the central volume flows, while the outer residual volume remains motionless. The tracer test also enabled the detection of preferential flow patterns. The tracer method was found to be quite useful as a diagnosis method for such a device in normal functioning. (C) 2008 Elsevier Ltd. All rights reserved. [less ▲]

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See detailIn situ follow-up of adsorption in activated carbon beds using X-ray microtomography
Almazan, Maria del Carmen; Léonard, Angélique ULg; Toye, Dominique ULg et al

in Kaskel, S.; Llewellyn, P.; Rodriguez-Reinoso, F. (Eds.) et al Characterisation of Porous Solids VII - Proceedings of the 8th International Symposium on the Characterisation of Porous Solids (2009)

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See detailSynthesis of Ag/TiO2 hybrid photocatalysts by sol-gel process with new P-alkoxide functionalized ligands
Lambert, Stéphanie ULg; Bied, Catherine; Bodson, Céline et al

Poster (2009)

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See detailModeling of a continuous rotary reactor for carbon nanotube synthesis by catalytic chemical vapor deposition
Pirard, Sophie ULg; Bossuot, Christophe; Pirard, Jean-Paul ULg

in AIChE Journal (2009), 55

The modeling of carbon nanotube production by the CCVD process in a continuous rotary reactor with mobile bed was performed according to a rigorous chemical reaction engineering approach. The geometric ... [more ▼]

The modeling of carbon nanotube production by the CCVD process in a continuous rotary reactor with mobile bed was performed according to a rigorous chemical reaction engineering approach. The geometric, hydrodynamic, physical and physicochemical factors governing the process were analyzed in order to establish the reactor equations. While the study of the hydrodynamic factor suggests a co-current plug-flow approximation, the physical factor mainly deals with the phenomena of transport and the transfer of mass, which can be neglected. Concerning the physicochemical factor, the modeling is based on knowledge of the expression of the initial reaction rate, and takes into account catalytic deactivation as a function of time, according to a sigmoid decreasing law. The reactor modeling allows obtaining the evolution of partial pressure, carbon nanotube production and catalytic deactivation along the reactor for given initial operating conditions. The comparison between experimental and calculated production highlights a very good fit of data. (c) 2009 American Institute of Chemical lEngineers AIChE J, 55: 675-686, 2009 [less ▲]

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See detailElectrochemical characterization of Pt/carbon xerogel and Pt/carbon aerogel catalysts
Job, Nathalie ULg; Maillard, F.; Marie, J. et al

Poster (2008, September 08)

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See detailStudying the chemical activation in carbon xerogels
Zubizarreta, Leire; Arenillas, A.; Pis, J. J. et al

Poster (2008, September 08)

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See detailCharacterization of the porous structure of biodegradable scaffolds obtained with supercritical CO2 as foaming agent
Léonard, Angélique ULg; Calberg, Cédric ULg; Kerckhofs, Greet ULg et al

in Journal of Porous Materials (2008), 15(4), 397-403

Poly(ε-caprolactone) foams were prepared, via a batch process, by using supercritical CO2 as foaming agent. Their porous structure was characterized through mercury porosimetry, helium and mercury ... [more ▼]

Poly(ε-caprolactone) foams were prepared, via a batch process, by using supercritical CO2 as foaming agent. Their porous structure was characterized through mercury porosimetry, helium and mercury pycnometry, scanning electron microscopy (SEM) and X-ray microtomography observations coupled with image analysis. The pore size distributions obtained by these two latter techniques show that the pore structure is more homogeneous when the foaming process is performed under a high CO2 saturation pressure (higher than 250 bars). [less ▲]

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See detailCaractérisation électrochimique de catalyseurs Pt/xérogel de carbone et Pt/aérogel de carbone
Job, Nathalie ULg; Maillard, F.; Marie, J. et al

Conference (2008, March 31)

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See detailTailoring the textural properties of activated carbon xerogels by chemical activation with KOH
Zubizarreta, Leire; Arenillas, Ana; Pirard, Jean-Paul ULg et al

in Microporous and Mesoporous Materials (2008), 115(3), 480-490

Resorcinol-formaldehyde xerogels synthesised with different resorcinol/sodium carbonate molar ratios were chemically activated either after drying or after drying and pyrolysis, using potassium hydroxide ... [more ▼]

Resorcinol-formaldehyde xerogels synthesised with different resorcinol/sodium carbonate molar ratios were chemically activated either after drying or after drying and pyrolysis, using potassium hydroxide. It was found that organic (i.e. dried) and carbon (i.e. pyrolysed) xerogels behave differently when subjected to chemical activation. In the case of carbon xerogels, the increase in the microporosity takes place without any significant modification to the meso/macroporosity formed during the synthesis step, leading to micromesoporous or micro-macroporous materials with a larger micropore volume. Furthermore, control of the microporosity is possible because its development depends on the amount of KOH used. However, when organic xerogels are activated, mainly microporous materials with BET specific surface areas of up to 2000 m(2) g(-1) are obtained, there hardly remaining any of the meso/macroporosity formed during the gel synthesis. Thus, the combination of different synthesis conditions and chemical activation with potassium hydroxide allows the textural properties of carbon xerogels to be tailored at both micropore and meso/macropore levels. (c) 2008 Elsevier Inc. All rights reserved. [less ▲]

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See detailFormation mechanism of Y-junctions in arrays of multi-walled carbon nanotubes
Zilli, Dario; Blacher, Silvia ULg; Cukierman, Ana Lea et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2008), 327(1-3), 140-143

Transmission electron microscopy of arrays of multi-walled carbon nanotubes reveals the presence of numerous Y-junctions. The diameter distributions of the samples are found to be bimodal, with one mode ... [more ▼]

Transmission electron microscopy of arrays of multi-walled carbon nanotubes reveals the presence of numerous Y-junctions. The diameter distributions of the samples are found to be bimodal, with one mode corresponding to the branches and the other mode to the trunk of the Y-junctions. The analysis of the micrographs shows that the junctions form via the merger of metal particles during the tip-growth of the tubes. (C) 2008 Elsevier B.V. All rights reserved. [less ▲]

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See detailDécomposition photocatalytique de polluants et de micro-organismes dans l'eau
Heinrichs, Benoît ULg; Pirard, Jean-Paul ULg; Lambert, Stéphanie ULg et al

E-print/Working paper (2008)

Dans le cadre de la réutilisation des eaux usées et de l’accès limité à l’eau potable dans certaines régions du globe, de nouvelles techniques de désinfection nécessitant de faibles consommations ... [more ▼]

Dans le cadre de la réutilisation des eaux usées et de l’accès limité à l’eau potable dans certaines régions du globe, de nouvelles techniques de désinfection nécessitant de faibles consommations d’énergie sont étudiées. Cette eau n’est pas toujours potable et contient des polluants qui induisent des mutations génétiques pouvant conduire au développement de cancers ou encore des micro-organismes pathogènes causant des maladies graves. Depuis la découverte des propriétés de photodégradation oxydante du dioxyde de titane (TiO2), la photocatalyse hétérogène est utilisée pour l’élimination des polluants environnementaux et des micro-organismes. [less ▲]

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See detailIron(III) species dispersed in porous silica through sol-gel chemistry
Heinrichs, Benoît ULg; Rebbouh, Leila; Geus, John W et al

in Journal of Non-Crystalline Solids (2008), 354(2-9), 665-672

Fe/SiO2 catalysts have been prepared by two different sol-gel methods, cogelation and dissolution. The cogelation and dissolution preparative methods lead to xerogels with fundamentally different pore ... [more ▼]

Fe/SiO2 catalysts have been prepared by two different sol-gel methods, cogelation and dissolution. The cogelation and dissolution preparative methods lead to xerogels with fundamentally different pore width distributions. The nature of the iron species obtained has been examined in detail by UN-visible and Mossbauer spectroscopy, and magnetic, transmission electron microscopy, and X-ray diffraction studies. There is no evidence for the presence of any ordered iron(III) oxides in the samples but all three contain two types of iron species, specifically paramagnetic high-spin iron(III) ions isolated in silica and iron(III) containing nanoparticles with a broad width distribution centered on 1.5 nm, nanoparticles that contain antiferromagnetically coupled clusters of a few ligated bridged iron(III) ions. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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