References of "Job, Nathalie"
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See detailEDLC electrodes from cellulose-based carbon aerogels : influence of the carbon's surface chemistry
Hildebrand, Claudia; Grzyb, Bartosz; Berthon-Fabry, Sandrine et al

in Proceedings of the International Carbon Conference 2009 (2009)

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See detailStudying chemical activation in carbon xerogels
Zubizaretta, Leire; Arenillas, Ana; Pis, Jose Juan et al

in Journal of Materials Science (2009), 44

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See detailNanostructured carbons as catalyst supports for PEM fuel cell electrodes
Job, Nathalie ULg; Berthon-Fabry, Sandrine; Chatenet, Marian et al

in Topics in Catalysis (2009), 52

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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 detailWater desorption from resorcinol-formaldehyde hydrogels and adsorption in the resulting xerogels
Escalona, Ivonne; Gommes, Cédric ULg; Job, Nathalie ULg et al

in Microporous & Mesoporous Materials (2009), 117

Water desorption isotherms of resorcinol-formaldehyde (RF) hydrogels and subsequent water adsorption isotherms of the resulting xerogels are determined using the static gravimetric method, at various ... [more ▼]

Water desorption isotherms of resorcinol-formaldehyde (RF) hydrogels and subsequent water adsorption isotherms of the resulting xerogels are determined using the static gravimetric method, at various temperatures. Isotherms obtained from samples synthesized at various pH are compared. Two different mechanisms are involved in RF hydrogels water desorption. At large relative humidity the capillary tension resulting from water removal induces a macroscopic shrinkage of the gel, whereas at low humidity water is evaporated with no network deformation. These two mechanisms are analyzed using a plastic deformation model and the Guggenheim-Anderson-de Boer (GAB) model, respectively. Adsorption isotherms of RF xerogels are analyzed using the GAB model. [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 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 detailEffect of the counter-ion of the basification agent on the pore texture of organic and carbon xerogels
Job, Nathalie ULg; Gommes, Cédric ULg; Pirard, René ULg et al

in Journal of Non-Crystalline Solids (2008), 354(40-41), 4698-4701

Organic and carbon xerogels were prepared by polycondensation of resorcinol with formaldehyde in water, followed by evaporative drying and, eventually, pyrolysis. The pH of the precursor's solution was ... [more ▼]

Organic and carbon xerogels were prepared by polycondensation of resorcinol with formaldehyde in water, followed by evaporative drying and, eventually, pyrolysis. The pH of the precursor's solution was fixed at 6.0 in all cases by adding various hydroxides as basification agent. Three alkali metal hydroxides (LiOH, NaOH and KOH) and three alkaline earth metals hydroxides (Ca(OH)(2), Ba(OH)(2), Sr(OH)(2)) were used. It was found that the pore texture of the organic and carbon xerogels is totally independent on the cation size, but depends on the charge and concentration of the counter-cation. Indeed, the pore size of the alkaline earth metal loaded samples is larger than that of the alkali metal-doped xerogels. As a matter of fact, to reach the same initial pH, the concentration in alkali metal hydroxide must be twice that of the alkaline earth metal base. The effect of ions on the pore texture was thus attributed to electrostatic effects on the microphase separation process that occurs prior to gelation. (C) 2008 Elsevier B.V. All rights reserved. [less ▲]

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See detailCarbon xerogels as catalyst supports for PEM fuel cell cathode
Job, Nathalie ULg; Marie, J.; Lambert, Stéphanie ULg et al

in Energy Conversion and Management (2008), 49

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See detailMicrowave drying as an effective method to obtain porous carbon xerogels
Zubizarreta, Leire; Arenillas, Ana; Menendez, J. A. et al

in Journal of Non-Crystalline Solids (2008), 354(33), 4024-4026

Microwave drying was used to prepare resorcinol-formaldehyde aqueous gels, without performing any pretreatment, and to see whether it was possible to use this drying option to obtain porous carbon ... [more ▼]

Microwave drying was used to prepare resorcinol-formaldehyde aqueous gels, without performing any pretreatment, and to see whether it was possible to use this drying option to obtain porous carbon xerogels with controlled textural properties. By using microwave drying, the process for obtaining carbon gels is greatly simplified, textural properties are controlled likewise with other drying methods, but the time involved in the process is significantly reduced and no pretreatment is necessary. Therefore, microwave drying could help to simplify the carbon xerogels synthesis and reduce the associated costs. (C) 2008 Elsevier B.V. All rights reserved. [less ▲]

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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 & 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 detailCritical opalescence points to thermodynamic instability:relevance to small-angle X-ray scattering of resorcinol–formaldehyde gel formation at low pH
Gommes, Cédric ULg; Job, Nathalie ULg; Pirard, Jean-Paul ULg et al

in Journal of Applied Crystallography (2008), 41(4), 663-668

During the formation at low pH of resorcinol–formaldehyde gels with a structure in the micrometre range, small-angle X-ray scattering exhibits a nonmonotonic intensity variation as a function of reaction ... [more ▼]

During the formation at low pH of resorcinol–formaldehyde gels with a structure in the micrometre range, small-angle X-ray scattering exhibits a nonmonotonic intensity variation as a function of reaction time. The data are analyzed in terms of scattering by statistical fluctuations of polymer concentration, the amplitude of which is maximal close to the critical point for phase separation between polymer and solvent. The data do not carry any morphological information, but they unambiguously show that the driving force of the gel formation is a thermodynamic instability of the polymerizing solution. [less ▲]

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See detailCarbon xerogels as catalyst supports
Job, Nathalie ULg; Léonard, Angélique ULg; Lambert, Stéphanie ULg et al

Poster (2007, August)

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See detailWater desorption isotherms of resorcinol-formaldehyde and carbon xerogels
Léonard, Angélique ULg; Escalona, I.; Job, Nathalie ULg et al

Poster (2007, July 15)

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See detailWater desorption isotherms of resorcinol-formaldehyde and carbon xerogels
Léonard, Angélique ULg; Escalona, Ivonne; Job, Nathalie ULg et al

in The American Carbon Society (Ed.) Proceedings of Carbon 2007 (2007, July)

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See detailRheological determination of the sol-gel transition during the aqueous synthesis of resorcinol-formaldehyde resins
Job, Nathalie ULg; Panariello, Fabian; Crine, Michel ULg et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2007), 293(1-3), 224-228

The sol-gel transition of organic gels prepared by polycondensation of resorcinol (R) with formaldehyde (F) in presence of sodium carbonate (C) was monitored by small amplitude oscillatory measurements ... [more ▼]

The sol-gel transition of organic gels prepared by polycondensation of resorcinol (R) with formaldehyde (F) in presence of sodium carbonate (C) was monitored by small amplitude oscillatory measurements, at a single frequency. The gelation time (t(g)) was determined from the evolution of the storage (G) and loss (G") moduli versus time. The influence of two synthesis variables, the resorcinol/sodium carbonate ratio (R/C) and the synthesis temperature (7), was investigated. The gelation time was found to decrease with increasing synthesis temperature and decreasing R/C ratio. The apparent activation energy of the reactional system leading to the gelation, calculated from the gelation times obtained between 50 and 90 degrees C, was found to be close to 80 kJ mol(-1) and independent of the R/C ratio. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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