References of "Léonard, Angélique"
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See detailX-ray microtomography: A porosity-based thresholding method to improve soil pore network characterization?
Beckers, Eléonore ULg; Plougonven, Erwan ULg; Roisin, Christian et al

in Geoderma (2014), 219-220

X-ray microtomography, through quantification of soil structure at the microscale, could greatly facilitate the current understanding of soil hydrodynamic behaviour. However, binarisation method and ... [more ▼]

X-ray microtomography, through quantification of soil structure at the microscale, could greatly facilitate the current understanding of soil hydrodynamic behaviour. However, binarisation method and processing choices are subjective and can have a strong impact on results and conclusions. In this study, we test a new method based on the porosity detectable by X-ray microtomography, while validation is achieved through comparison of soil microtomogram information with soil physical measurements. These measurements consist of water retention and unsaturated hydraulic conductivity using two different soil populations with only structural differences. To assess the porosity-based method performances, we compare it to four other methods, namely the global method of Otsu and three recent soil-dedicated local methods. The robustness of the porosity-based method is also tested in regard to different pre-processing procedures. In this paper we demonstrate that soil segmentation through a porosity-based method is an interesting issue. Indeed, it is less demanding in terms of time and computational requirements than its alternatives, and combines robustness and performances broadly comparable with the recent local methods. [less ▲]

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See detailPreparation of polyaniline-modified local clay and study of its sorption capacity
Benhebal, Hadj; Chaid, Messaoud; Léonard, Angélique ULg et al

in Journal of Nanostructure in Chemistry (2014), 4(98), 6

Clay minerals are frequently used in adsorption processes with aqueous solution; it was found that the adsorption properties of clays change when the samples are modified. In this context, polyaniline ... [more ▼]

Clay minerals are frequently used in adsorption processes with aqueous solution; it was found that the adsorption properties of clays change when the samples are modified. In this context, polyaniline-modified clay nanocomposite (at 10 %) was prepared by in situ polymerization processes. The structural and morphological characteristics of the synthesized material are systematically examined by X-ray diffraction, scanning electron microscopy, thermo-gravimetry, differential scanning calorimetry and infrared spectroscopy techniques. The adsorption property of the modified clay was evaluated for the removal of a reactive dye (methylene blue) from aqueous solution at room temperature (25 C) via batch adsorption. [less ▲]

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See detailExperimental study on dehumidification/regeneration of liquid desiccant: LiBr solution
Bouzenada, Saliha; Kaabi, Abdennacer N; Fraikin, Laurent ULg et al

in Procedia Computer Science (2014), 32

The growing demand for air conditioning has caused a significant increase in demand for energy resources. The traditional commercial, non natural working fluids, like CFC, HCFC and HFC result in both ... [more ▼]

The growing demand for air conditioning has caused a significant increase in demand for energy resources. The traditional commercial, non natural working fluids, like CFC, HCFC and HFC result in both ozone depletion and global warming emission of CO2. The use of hygroscopic salts in direct contact with moist air provides an attractive alternative to conventional cooling systems. The liquid desiccant can substitute the dangerous fluids. The main operations in Liquid Desiccant Cooling System (LDCS) are dehumidification and regeneration. This paper presents an experimental study of dehumidification/regeneration processes using LiBr as liquid desiccant in direct contact with the air at different operating conditions. An analysis of the mass transfer is made in order to prove is this material is the best liquid desiccant for LDCS. Experimental results showed the effect of air conditions on mass transfer. It can be seen that LiBr is able to absorb moisture and can be regenerated at low temperature. © 2014 Published by Elsevier B.V. [less ▲]

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See detailExperimental arguments concerning a hydraulic connection layer during limestone convective drying
Prime, Noémie ULg; Housni, Z.; Fraikin, Laurent ULg et al

in Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 (2014)

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See detail“Product-oriented engineering” applied to the development of porous scaffolds for tissue engineering
de Bien, Charlotte ULg; Ounally, T; Collard, Valérie ULg et al

in 7th World Congress in Industrial Process Tomography (2014)

This work applies a “product-oriented engineering” approach to the development of porous scaffolds for tissue engineering. Polylactic acid scaffolds were obtained by a freeze-drying process. Their 2D/3D ... [more ▼]

This work applies a “product-oriented engineering” approach to the development of porous scaffolds for tissue engineering. Polylactic acid scaffolds were obtained by a freeze-drying process. Their 2D/3D microstructure was characterized by X-ray microtomography and related to the operating conditions used. Two types of scaffold end-use properties were characterized in relation to their microstructure: the mechanical and the transport properties. Scaffold young's modulus was computed from data measured on tension-compression devices. To evaluate the permeability, Darcy’s experiments were carried out. The obtained results allowed highlighting the quantitative relationships existing between elaboration conditions, microstructure and end-use properties of the fabricated PLA scaffolds. © 2014 International Society for Industrial Process Tomography. [less ▲]

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See detailX-ray microtomography: A new tool to follow soft material shrinkage during convective drying
Léonard, Angélique ULg; Blacher, Silvia ULg; Marchot, Pierre ULg et al

in 2nd World Congress on Industrial Process Tomography : Hannover, Germany 29-31 août 2001 (2014)

X-ray microtomography is proposed as a new tool to investigate the shrinkage of soft material which occurs during convective drying. Reliable shrinkage curves are obtained with samples of wastewater ... [more ▼]

X-ray microtomography is proposed as a new tool to investigate the shrinkage of soft material which occurs during convective drying. Reliable shrinkage curves are obtained with samples of wastewater treatment sludge. We develop a four zones model to describe the drying kinetics based of the experimental data provided by X-ray microtomography. The observation of the drying and shrinkage curves allows us to determine 3 critical water content values, which define different drying zones where extragranular, intragranular or mixed limitations prevail. When drying is externally controlled, the decrease of the drying rate observed during experiments can be related to the reduction of the external area of the sample. © 2014 International Society for Industrial Process Tomography. [less ▲]

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See detailLife Cycle Analysis (LCA) of photovoltaic panels: A review
Gerbinet, Saïcha ULg; Belboom, Sandra ULg; Léonard, Angélique ULg

in Renewable and Sustainable Energy Reviews (2014), 38

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See detailCharacterization of multi-walled carbon nanotube dispersion in resorcinol-formaldehyde aerogel
Haghgoo, Majid; Yousefi, Ali Akbar; Zohouriaan Mehr, Mohammad Jalal et al

in Microporous and Mesoporous Materials (2014), 184

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See detailErratum: Characterization of multi-walled carbon nanotube dispersion in resorcinol-formaldehyde aerogels (Microporous and Mesoporous Materials (2014) 184 (97-104))
Haghgoo, M.; Yousefi, A. A.; Zohouriaan Mehr, M. J. et al

in Microporous and Mesoporous Materials (2014), 195

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See detailCharacterization of dry and wet sawdust porous beds
Parmentier, Nicolas; Plougonven, Erwan ULg; Léonard, Angélique ULg et al

in Powder Technology (2014), 264

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See detailImportance of LUC and ILUC on the carbon footprint of bioproduct: case of bio-HDPE
Belboom, Sandra ULg; Léonard, Angélique ULg

in Matériaux et Techniques (2014), 102(2),

Suite à la diminution des ressources fossiles et à l’augmentation des émissions des gaz à effet de serre, des solutions sont nécessaires pour remplacer les produits issus du pétrole. Cela a pour ... [more ▼]

Suite à la diminution des ressources fossiles et à l’augmentation des émissions des gaz à effet de serre, des solutions sont nécessaires pour remplacer les produits issus du pétrole. Cela a pour conséquence une constante augmentation du nombre de produits biobasés développés à partir de ressources agricoles. Cette étude évalue l’empreinte carbone du polyéthylène haute densité (PEHD) produit à partir de canne à sucre brésilienne ou de betterave belge. Le but de cette étude est de comparer l’empreinte carbone du bio-PEHD avec le PEHD fossile en considérant l’effet du changement d’affectation des sols. Les frontières communes des systèmes agricoles regroupent l’étape de culture de la canne à sucre et de la betterave, avec toutes les consommations associées d’énergie et d’engrais, le transport depuis le champ jusqu’à l’unité industrielle, la transformation des plantes sucrières en bioéthanol hydraté, la valorisation des sous-produits, la polymérisation et l’incinération du PEHD. Le scénario fossile comprend la production d’éthylène, sa polymérisation et l’incinération du PEHD. La comparaison du cycle de vie entier des PEHD biobasé et fossile montre des émissions de GES plus faibles avec le produit biobasé, ce qui est l’effet voulu. Ce résultat est uniquement valide s’il n’y pas de changement direct ou indirect d’affectation des sols. Pour évaluer l’impact environnemental de la déforestation ou de la transformation d’un pâturage en champ, les lignes directrices de l’Union Européenne ont été suivies afin de calculer les émissions de CO2 en fonction de divers paramètres. Pour la canne à sucre, le changement direct d’affectation des sols (LUC) est défini par la transformation de pâturages en champs dans la région de Sao Paulo au Brésil. Trois scénarios ont été développés, basés sur différentes pratiques agricoles pour les pâturages et les champs (labour et engrais) : le meilleur, le pire et le moyen. Le meilleur cas engendre un gain environnemental supplémentaire pour le produit biobasé. Le pire et le moyen amènent des émissions complémentaires. Un temps de retour, considérant le temps nécessaire pour récupérer à nouveau un gain environnemental comparativement au produit fossile, a été calculé pour le scenario moyen et s’élève à 12 ans. Le changement indirect d’affectation des sols pour la canne à sucre est modélisé comme étant la transformation d’une forêt en champ induite par les effets du changement direct décrit ci-avant. Le taux de déforestation peut varier entre 16 et 100%, dépendant des statistiques utilisées et entrainant un temps de retour de respectivement 26 et 101 ans. Pour la betterave, aucun changement direct n’est considéré. En effet, aucune expansion des terres agricoles ne peut être envisagée en Belgique au vu des faibles surfaces disponibles. Si une augmentation en termes de production de bioplastiques a lieu, la Belgique devra importer de la betterave provenant des pays voisins, ce qui peut induire un changement indirect d’affectation des sols. Dans cette étude, la betterave est supposée provenir des Pays-Bas. Celle-ci est cultivée sur des pâturages préalablement transformés en champs. Ce scénario moyen induit un temps de retour de 8 ans. Cette étude a mis en évidence l’importance du changement direct et indirect d’affectation des sols, spécialement pour les cultures énergétiques dédiées au remplacement des produits fossiles. Cet effet peut renverser les résultats attendus et engendrer de longs temps de retour. [less ▲]

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See detailVisible-light photo-activity of alkali metal doped ZnO
Benhebal, Hadj; Chaib, Messaoud; Malengreaux, Charline ULg et al

in Journal of the Taiwan Institute of Chemical Engineers (2014), 45(1), 249-253

In order to utilize visible light more efficiently in the field of photocatalysis, Li, Na and K-doped ZnO nanoparticles were prepared using a sol–gel method. The obtained samples were characterized by BET ... [more ▼]

In order to utilize visible light more efficiently in the field of photocatalysis, Li, Na and K-doped ZnO nanoparticles were prepared using a sol–gel method. The obtained samples were characterized by BET surface area measurements, X-ray diffraction, scanning electron microscopy and UV–vis analysis. The photocatalytic activity of the photocatalysts was evaluated for the degradation of p-nitrophenol (p-NP) under visible light irradiation. It has been observed that these photocatalysts could be a promising photocatalyst for degradation of organic molecules as compared to transition metal doped ZnO under visible light. Li-doped ZnO is the most active photocatalyst and shows high photocatalytic activity for the degradation of p-nitrophenol (p-NP). The enhanced photocatalytic activity of Li-doped ZnO is mainly due to the electron trapping by lithium metal ions, small particle size, large surface area, and high surface roughness of the photocatalysts. [less ▲]

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See detailModeling and Simulation of Heat and Mass Transfer During Convective Drying of Wastewater Sludge with Introduction of Shrinkage Phenomena
Bennamoun, Lyes ULg; Fraikin, Laurent ULg; Léonard, Angélique ULg

in Drying Technology (2014), 32(1), 13-22

Wastewater sludge is dried in a convective dryer using air temperatures varying from 80°C to 200°C, velocities changing from 1 m · s−1 to 2 m · s−1, and humidities ranging from . The convective dryer is ... [more ▼]

Wastewater sludge is dried in a convective dryer using air temperatures varying from 80°C to 200°C, velocities changing from 1 m · s−1 to 2 m · s−1, and humidities ranging from . The convective dryer is equipped with a camera and an infrared pyrometer to follow respectively the external surface and the temperature of the product. The experimental results show that drying kinetic can be divided into three phases: two short first phases, called adaptation and constant drying phases, and a long third phase, called falling drying rate phase. As the moisture content decreases, the camera confirms simultaneous shrinkage effect with the volume reduction of the product of about 30–45% of the initial volume. Moreover, an increase of the product temperature towards air temperature was measured with the infrared pyrometer. In a second step of this study, the experimental results are modeled and simulated using heat and mass balances applied to the product and the heated air. The drying curve is rightly expressed with fourth-degree polynomial model with a correlation coefficient that approximates the unity and with low calculated errors. An outstanding determination of the heat transfer coefficient has permitted calculating the product temperature with good agreement with experimental results. The heat transfer coefficient expressed by means of Nusselt number is presented as a function of Reynolds and Prandlt numbers, changeable with air and product characteristics taking into account shrinkage effect. Moreover, as the applied air temperatures are sufficiently high, transfer by radiation is not neglected and is introduced in the mathematical model. [less ▲]

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See detailModeling of Wastewater Sludge Drying with Determination of Diffusivity Moisture
Bennamoun, Lyes ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

in Journal of Residuals Science and Technology [=JRST] (2013), 10(4), 165

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See detailImpact of sludge storage duration on its dewatering and drying ability
Pambou, Yvon-Bert ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Poster (2013, November 15)

Annual production of sewage sludge in Europe is estimated at more than eleven million tons of dry matter [1]. Use in agriculture and incineration are the main ways of valorization. In this context, drying ... [more ▼]

Annual production of sewage sludge in Europe is estimated at more than eleven million tons of dry matter [1]. Use in agriculture and incineration are the main ways of valorization. In this context, drying of residual sludge appears as an essential step after mechanical dewatering. It reduces the costs of storage, transport and allows the sludge stabilization. However, this process is highly energy consuming and still needs to be optimized as it constitutes an important economic and environmental issue [2]. The aim of this paper is to study sludge variability during storage duration, because sludge is a living material that can rapidly change. The study was performed on activated sludge samples collected after thickening from the waste water treatment plant of the Grosses- Battes, closed to University of Liège. The samples were stored in a vessel at fresh room temperature and under stirring. Two types of experiments were conducted, the one (A) during three weeks with one trial a week and the other (B) during five days with one trial a day. The Zetag 7587 conditioner was used for sludge flocculation prior to mechanical dewatering. Optimum dosage was determined by Capillary Suction Time (CST) measurements, it was closed to 18 g/kg DS The dewatering process was made using a normalized filtration-expression cell (AFNOR 1979) under 5 bar of pressure. , the cake dryness obtain was respectively 17 .and 15 %DS for experiment A and B. Before drying, sludge samples were extruded through a cylinder die of diameter and cut at a height of 14 mm, the weight of sample being finally about 2.5 g. The drying experiments were carried out in a specially designed convective dryer, by controlling three operating conditions: the air temperature of 130 °C, the superficial velocity of 1 m/s and the absolute humidity of the air fixed at 0.005 kgwater/ kgDS. The same set up operation was applied for trial [3]. Figure 1 shows the curves of mass loss during the drying, obtained after 1, 8 and 15 days of storage. A poor repeatability of drying curves was observed for activated sludge samples with the increase of storage time on 3 weeks. Whereas figure 2 presents the drying curves for the one week storage, a good repeatability was obtained. No significant effect of sludge variability in a week has shown. It is thus advisable to use a sludge sample during five days and to consider a weekly renewal. [less ▲]

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See detail« Product-oriented engineering » applied to the development of porous scaffolds for tissue engineering.
de Bien, Charlotte ULg; Ounally, Thameur; Collard, Valérie ULg et al

Poster (2013, November 15)

Ce travail vise à appliquer une approche « génie-orienté produit » à la fabrication de matrices poreuses synthétiques (scaffolds) susceptibles d’être utilisées en ingénierie tissulaire [1]. Parmi les ... [more ▼]

Ce travail vise à appliquer une approche « génie-orienté produit » à la fabrication de matrices poreuses synthétiques (scaffolds) susceptibles d’être utilisées en ingénierie tissulaire [1]. Parmi les différents polymères biosourcés et biodégradables déjà utilisés pour la fabrication de scaffolds, l’acide polylactique (PLA) a été choisi [2]. Des matrices poreuses ont été obtenues par un procédé de moussage par lyophilisation puis leur microstructure 2D/3D a été caractérisée par microtomographie à rayons X avant d’être mise en lien avec les conditions d’élaboration testées [3]. La diminution de la porosité ainsi que l’augmentation de l’épaisseur des parois avec l’augmentation de rapport polymère/solvant ont été confirmées. [less ▲]

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See detailUse of Life Cycle Assessment to support in the Eco-Design of a glass-wool process
Gerbinet, Saïcha ULg; Renzoni, Roberto ULg; Briard, Vincent et al

Poster (2013, November 15)

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