References of "Léonard, Angélique"
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See detailImpact of Storage Duration on the Gaseous Emissions during Convective Drying of Urban Residual Sludges
Fraikin, Laurent ULg; Salmon, Thierry ULg; Herbreteau, B. et al

in Chemical Engineering and Technology (2011), 34(7), 1172--1176

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See detailUnderstanding and preventing structural changes during drying of gels
Metzger, T.; Léonard, Angélique ULg; Jomaa, W. et al

in Tsotsas, E.; Mujumdar, A. S. (Eds.) Modern Drying Technology, Vol 3. Product quality and formulation (2011)

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See detailManagement of Wastewater Sludge's: A Hot Topic at the European Level
Léonard, Angélique ULg

in Journal of Residuals Science and Technology [=JRST] (2011), 8(2), 38-38

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See detailLife cycle assessment as decision tool for sustainable choices in mineral materials field: environmental declarations of Belgian products and their foreign equivalents
Belboom, Sandra ULg; Renzoni, Roberto ULg; Léonard, Angélique ULg et al

in Martens, Per Nicolai (Ed.) Sustainable Development in the Minerals Industry : Institute of Mining Engineering I, RWTH Aachen University, 14-17 June 2011 (2011)

Construction is a field which is concerned by environment. Tools as environmental product declarations are increasingly often used to compare several products and to take account of the environmental ... [more ▼]

Construction is a field which is concerned by environment. Tools as environmental product declarations are increasingly often used to compare several products and to take account of the environmental sphere in the choice. Environmental declarations of Belgian bluestone and sandstone products were realized in accordance with the ISO standards and following the standard NF P 01-010. The main goals of these studies were to obtain Belgian environmental product declarations to strengthen existing databases and to provide defences against Asian competition. Indeed, competition with China for bluestone products and with India for sandstone pavement is very important due the fact of the very competitive prices for foreign products. The impacts on climate change, resources and acidification of the sole transport were taken into account for foreign products and they are at less as important as these obtained for the whole life cycle of Belgian products. [less ▲]

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See detailInfluence of space-filling materials in subantral bone augmentation: blood clot vs. autogenous bone chips vs. bovine hydroxyapatite
Lambert, France ULg; Léonard, Angélique ULg; Drion, Pierre ULg et al

in Clinical Oral Implants Research (2011), 22(5), 538-545

Aim: The first objective of the present study was to compare the short- and long-term 3D volume stability of sub-sinusal bone regeneration in rabbits using different space fillers. The second objective ... [more ▼]

Aim: The first objective of the present study was to compare the short- and long-term 3D volume stability of sub-sinusal bone regeneration in rabbits using different space fillers. The second objective was to assess qualitatively and quantitatively the early bone formation process and long-term behavior of the regenerated bone. Materials and methods: Fifteen rabbits underwent a double sinus lift procedure using: blood clot (Clot), autogenous bone chips (Auto) and bovine hydroxyapatite (BHA). Animals were euthanized at 1 week, 5 weeks and 6 months. Samples were subjected to X-ray microtomography and histology. Variations in the volume of bone augmentations were calculated at different time points. Qualitative analysis was performed using 7 μm sections and quantitative histomorphometric analyses were carried out using scanning electron microscopy. Results: From baseline (100%) to 5 weeks, the augmented volumes declined to 17.3% (Clot), 57.6% (Auto) and 90.6% (BHA). After 6 months, only 19.4% (Clot) and 31.4% (Auto) of initial volumes were found, while it remained more stable in the BHA group (84%). At 1 week, an initial osteogenesis process could be observed in the three groups along the bone walls. At 5 weeks, despite a significant decline in the volume, newly formed bone density was higher with Clot and Auto than with BHA. At 6 months, bone densities were statistically similar in the three groups. However, after 6 months, the surface invaded by newly formed bone (regenerated area) was significantly higher when BHA was used as space filler. In the BHA group, the biomaterial area slightly decreased from 42.7% (1 week) to 40% (5 weeks) and 34.9% (6 months) and the density of the composite regenerated tissue (bone+BHA) reached >50% at 6 months. Conclusions and clinical implications: The three space fillers allowed bone formation to occur. Nevertheless, augmented volumes declined in the Clot and Auto groups, while they remained stable with BHA. A slowly resorbable biomaterial might be suitable in sub-sinusal bone augmentation for preventing the re-expansion process and for augmenting the density of the regenerated tissues. [less ▲]

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See detailVecteurs énergétiques et énergies renouvelables
Léonard, Angélique ULg

Learning material (2011)

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See detailImpact of thresholding techniques on X-ray soil microtomogram analyses
Beckers, Eléonore ULg; Léonard, Angélique ULg; Beekkerk van Ruth, Jöran ULg et al

in Geophysical Research Abstracts (2011), 13

Using X-ray microtomography, 3D soil structure can be visualised and analysed through useful factors like pore size distribution, shape, connectivity, orientation, etc. X-ray scans yield grey-level 2D ... [more ▼]

Using X-ray microtomography, 3D soil structure can be visualised and analysed through useful factors like pore size distribution, shape, connectivity, orientation, etc. X-ray scans yield grey-level 2D images, which can be recombined to form 3D structures. Treatments of the grey-level images can consist of either a binarization -distinguishing soil and pores- or a permeability level attribution directly linked to the grey-level values. The latter leads to problems in order to assign a permeability for each point (in soil a same grey level value can be assigned to points with a different permeability), as well as to analyse the 3D structure. On the other hand, treatment of black and white 3D structures is well-handled. However, the impact of the choice of one thresholding technique on the resulting images has already been demonstrated. Moreover, thresholding methods are various and numerous. Many of them are based on the image histogram analysis. But because of the soil complexity, the relevance of these techniques becomes debatable, with a risk of producing non reliable images. We propose to palliate this with a simple new algorithm based on physical measurements: it uses a loop fixing the threshold value in order to match the measured porosity for each sample. In this communication, our point is to highlight the impact of different thresholding techniques on the analysis and interpretation of our soil microtomograms. The underlying questions could be: Does the thresholding method influence our conclusions? Are the results depending on the sample itself or on the methodology? In order to answer these questions we tested the Otsu technique and our physically based algorithm. Soils samples were removed from the upper layer (Ap horizon) of a silty soil (Gentinnes, Brabant Walloon, Belgium) in plots with different management practices. In fact, since 2004, the field has been cultivated in conventional tillage (CT) or reduced tillage (RT). In order to empty the meso- and macroporosity, samples were placed under a 1.5 MPa pressure (Richards apparatus). Samples were then scanned by X-ray microtomography using a Skyscan-1172 high-resolution desktop micro-CT system (Skyscan, Kontich, Belgium). The cone beam source operated at 100 kV, using an aluminium filter. The detector configuration, i.e. 1048x2000 pixels with a 16-bit X-ray camera, and the distance source-object-camera were adjusted to produce images with a pixel size of 17 µm. Porosity was measured for each scanned sample. Then the threshold methods -the Otsu technique on one hand and our developed algorithm on the other - were applied, and morphological factors were calculated for both methods. A comparison of the first results shows a threshold influence on average porosity and number of pores, but also on connectivity factors and size distribution. The apparent porosity of the images, as well as connectivity, is underestimated with the Otsu technique. Despite the fact that the changes induced by thresholding are more important for RT than CT, global conclusions about the comparison of these agricultural practices are approximately the same in this case. However, differences between tillage systems are less important with the Otsu method, confirming the impact of choosing the adapted threshold method. [less ▲]

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See detailLife Cycle Assessment: a key decision tool for biomass valorization
Belboom, Sandra ULg; Léonard, Angélique ULg

Conference given outside the academic context (2010)

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See detailEvolution des structures de sols sous itinéraires techniques contrastés : relations entre courbes de rétention et analyse par microtomographie à rayons X
Beckers, Eléonore ULg; Roisin, Christian; Léonard, Angélique ULg et al

in Milieux Poreux et Transferts Hydriques (2010, November), 56

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were ... [more ▼]

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were measured, and the characterization of soils porosity was made using x-ray microtomography measurements. Results show differences in the meso as well as in the macroporosity. [less ▲]

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See detailEvolution des structures de sols sous itinéraires techniques contrastés : relation entre courbes de rétention et analyse par microtomographie aux rayons X
Beckers, Eléonore ULg; Roisin, Christian; Léonard, Angélique ULg et al

Poster (2010, November)

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were ... [more ▼]

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were measured, and the characterization of soils porosity was made using x-ray microtomography measurements. Results show differences in the meso as well as in the macroporosity. [less ▲]

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See detailImpact of storage duration on the emissions of ammonia and VOC during the convective drying of urban residual sludges
Fraikin, Laurent ULg; Herbreteau, Benjamin; Chaucherie, Xavier et al

in Tsotsas, E.; Metzger, T.; Peglow, M. (Eds.) Proceedings of IDS 2010 - Drying 2010 (2010, October)

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See detailContribution to the modeling of wastewater sludge drying kinetics: study of the operating conditions effect
Bennamoun, Lyes; Belhamri, A.; Léonard, Angélique ULg

in Tsotsas, E.; Metzger, T.; Peglow, M. (Eds.) Proceedings of IDS 2010 - Drying 2010 (2010, October)

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See detailOn the modeling of convective drying tests on soil samples in non-isothermal conditions
Gerard, Pierre ULg; Léonard, Angélique ULg; Charlier, Robert ULg et al

in Tsotsas, E.; Metzger, T.; Peglow, M. (Eds.) Proceedings of IDS 2010 - Drying 2010 (2010, October)

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See detailAspects pratico-techniques du séchage des boues d'épuration
Léonard, Angélique ULg; Crine, Michel ULg

Conference given outside the academic context (2010)

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See detailA comparison of physical activation of carbon xerogels with carbon dioxide with chemical activation using hydroxides
Contreras, María S; Páez, Carlos A; Zubizarreta, Leire et al

in Carbon (2010), 48(11), 3157-3168

Carbon xerogels synthesized with a fixed resorcinol/sodium carbonate molar ratio (R/C) were physically activated using CO2. The effect of activation temperature and activation time on the final properties ... [more ▼]

Carbon xerogels synthesized with a fixed resorcinol/sodium carbonate molar ratio (R/C) were physically activated using CO2. The effect of activation temperature and activation time on the final properties of the activated carbon xerogels was evaluated. The specific surface area increases from ~600 m2 g-1 to 2000 m2 g-1 and more by increasing the temperature and duration of the activation step. A comparison between physical activation with CO2 and chemical activation with hydroxides was also performed: it was found that both processes produce an increase of the micropore volume and specific surface area without altering the meso-macroporosity developed during the synthesis. However, chemical activation can lead to the development of the narrow microporosity mainly whereas, in physical activation, the widening of the narrow micropores takes place whatever the process conditions. [less ▲]

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See detailImpact of storage at 4°C on the study of sludge drying emissions
Fraikin, Laurent ULg; Herbreteau, Benjamin; Chaucherie, Xavier et al

Conference (2010, September)

Detailed reference viewed: 55 (23 ULg)