References of "Léonard, Angélique"
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See detailEnvironmental product declarations of mineral paving, a tool for sustainable product choices
Belboom, Sandra ULg; Renzoni, Roberto ULg; Tourneur, Francis ULg et al

Poster (2012, May 30)

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental ... [more ▼]

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental product declarations to strengthen existing databases and to get similar information for their Asian counterparts. Indeed, competition with China for bluestone products and with India for sandstone pavement is very important due to very competitive prices despite their foreign origin and possibly higher induced environmental impacts. Environmental product declarations of Belgian bluestone and sandstone products were conducted in accordance with the ISO standards and following the stand-ard NF P 01-010. CML 2001 method was used to obtain environmental impacts for ten categories as climate change, acidification, abiotic resources depletion, etc. Boundaries of the Belgian systems are the same and the life cycle assessment comprises all steps from the extraction of minerals to the implementation on site. Use and end of life steps were neglected due to the low required maintenance and the inert nature of the paving. For Asian products, the analysis is reduced to the transportation of the functional unit, mainly due to the lack of reliable data. This work highlights the negative effect of long distance transportation of heavy and non-energetic products. Indeed, the environmental impacts of the sole transport of Asian products are at least as important as those obtained for the whole life cycle of Belgian products, whatever the category taken into account (climate change, acidification, air pollution, etc.). CML 2001 methodology was successfully applied to these five studies about three Belgian products and two abroad transportation steps. Comparison of the 5 corresponding environmental product declarations permits to highlight the importance of the transport on environment and to promote, supposing equal performance, local prod-ucts in a more environmental-friendly point of view. [less ▲]

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See detailCharacterisation of macadamia nuts using X-ray microtomography
Plougonven, Erwan ULg; Srichamnong, Warangkana; Srzednicki, George et al

in Micro-CT User Meeting Abstract Book (2012, April 05)

Macadamia nuts are among the most nutritious and highest in monounsaturated oil content among edible nuts1. They are widely grown in Australia (46 % of total production), United States of America ... [more ▼]

Macadamia nuts are among the most nutritious and highest in monounsaturated oil content among edible nuts1. They are widely grown in Australia (46 % of total production), United States of America, especially in Hawaii, South Africa and Guatemala2. In practice, there are several steps involved in macadamia processing, including sorting and grading, drying, cracking, roasting, packaging and storage. Drying is a very crucial step as it needs to preserve macadamia quality as well as enhance storage stability through the reduction of water activity. It is obvious that physical properties of the nut contribute to its drying characteristics, and hence its storage stability. Accurate measures such as kernel volume ratio or shell density could help for improving drying efficiency. We present a methodology to investigate structural differences between varieties of macadamia nuts in order to understand the factors involved in storage stability. Fresh nuts-in-shell are scanned by X-ray microtomography, and the different parts of the nuts (shell, kernel, tracheids) are segmented by a set of classical 3D image operators. After image segmentation, volumes are determined, and additional weighing of the nuts allows density measurements. These quantities are plotted for several nuts from each variety. [less ▲]

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See detailDevelopment of a biomechanical model of deer antler cancellous bone based on X-ray microtomographic images
de Bien, Charlotte ULg; Mengoni, Marlène ULg; D'Otreppe, Vinciane ULg et al

in Micro-CT User Meeting 2012 - Abstract Book (2012, April)

Finite element models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. The aim of this paper is to develop and validate a ... [more ▼]

Finite element models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. The aim of this paper is to develop and validate a biomechanical model for deer antler cancellous bone tissue based on X-ray microtomographic images. In order to simulate the mechanical behavior under compressive load using a finite element model, images obtained by X-ray microtomography were exported into Metafor, which is an non-linear finite element software initially developed at University of Liège for metal forming processes. This software has recently found biomedical applications. The ultimate goal is to compare model predictions with the mechanical behavior observed experimentally using the Skyscan material testing stage under compression mode. The creation of the biomechanical model mesh from segmented μCT images, its integration into the software Metafor and the simulation of a compression test are described in this paper. [less ▲]

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See detailMicrostructure characterisation of nanocomposite polymeric foams by X-ray microtomography
Plougonven, Erwan ULg; Detrembleur, Christophe ULg; Tran, Minh Phuong ULg et al

Poster (2012, March 26)

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon ... [more ▼]

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon nanotubes inside a polymer matrix shows exceptional electromagnetic interference shielding effectiveness when foamed. However, the effective properties of such materials strongly depend on the shape and topology of the microstructural cells. An accurate method for investigating the cellular microstructure is X-ray microtomography (XRμT), for it is non-destructive, and it provides 3D geometric information. Although it cannot be used to observe nanofiller dispersion, it has a strong potential for cell structure characterisation. In order to reduce the need for trial and error in tailoring these materials, our objective is to quantify, using XRμT, cellular microstructure, for two different types of foaming procedures, namely supercritical CO2 batch foaming and freeze drying, to be able to establish a link between the structure and its shielding effectiveness. The main difficulty stems from the type of material being studied: it is light, therefore hardly absorbs X-rays, cell size is small compared to the resolution capacity of the tomograph, and cell wall thickness is extremely thin in some cases, making them very hard to discern in the images. For these reasons, common image analysis tools for identifying and delimiting objects in an image prove impractical. We propose an original method that uses the 3D autocorrelation function of the tomograms to determine statistical information from these images, such as average cell size and anisotropy, without the need to binarise and segment the images. [less ▲]

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See detailEnvironmental product declarations of mineral paving, a tool for sustainable product choices
Belboom, Sandra ULg; Renzoni, Roberto ULg; Tourneur, Francis ULg et al

Poster (2012, March 22)

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental ... [more ▼]

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental product declarations to strengthen existing databases and to get similar information for their Asian counterparts. Indeed, competition with China for bluestone products and with India for sandstone pavement is very important due to very competitive prices despite their foreign origin and possibly higher induced environmental impacts. [less ▲]

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See detailAnalyse des mécanismes de transfert de fluides lors d'essais de séchage convectif sur un limon
Gerard, Pierre ULg; Léonard, Angélique ULg; Charlier, Robert ULg et al

in Skoczykas, Frédéric; Davy, Catherine; Agostini, Franck (Eds.) et al Actes du colloque Transfert 2012 - Propriétés de transfert des géomatériaux (2012, March)

Des essais de séchage convectif ont été réalisés sur des échantillons de limon en vue de quantifier la cinétique de perte de masse. Ces essais ont été analysés sous l’hypothèse de l’existence d’une couche ... [more ▼]

Des essais de séchage convectif ont été réalisés sur des échantillons de limon en vue de quantifier la cinétique de perte de masse. Ces essais ont été analysés sous l’hypothèse de l’existence d’une couche limite en paroi de l’échantillon, dans laquelle des transferts de masse et de chaleur ont lieu. L’article met en avant l’intérêt de modélisations thermo-hydrauliques pour comprendre les transferts de fluides au sein de l’échantillon. Une analyse précise des résultats numériques permet de déterminer si les transferts internes sont constitués principalement d’advection d’eau liquide jusqu’à la paroi suivi par de l’évaporation, ou plutôt de l’avancée d’un front d’évaporation au sein de l’échantillon suivi par de la diffusion de la vapeur jusqu’à la paroi. [less ▲]

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See detailEnergetic systems evaluation using Life Cycle Assessment
Belboom, Sandra ULg; Léonard, Angélique ULg

Scientific conference (2012, February 08)

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See detailA non-linear homogeneous model for bone-like materials under compressive load.
Mengoni, Marlène ULg; Voide, Romain; de Bien, Charlotte ULg et al

in International Journal for Numerical Methods in Biomedical Engineering (2012), 28(2), 334-348

Finite element (FE) models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. In order to simulate non-linear behavior, which ... [more ▼]

Finite element (FE) models accurately compute the mechanical response of bone and bone-like materials when the models include their detailed microstructure. In order to simulate non-linear behavior, which currently is only feasible at the expense of extremely high computational costs, coarser models can be used if the local morphology has been linked to the apparent mechanical behavior. The aim of this paper is to implement and validate such a constitutive law. This law is able to capture the non-linear structural behavior of bone-like materials through the use of fabric tensors. It also allows for irreversible strains using an elastoplastic material model incorporating hardening. These features are expressed in a constitutive law based on the anisotropic continuum damage theory coupled with isotropic elastoplasticity in a finite strains framework. This material model was implemented into Metafor, a non-linear FE software. The implementation was validated against experimental data of cylindrical samples subjected to compression. Three materials with bone-like microstructure were tested : aluminum foams of variable density (ERG, Oakland, CA), PLA (polylactic acid) foam (CERM, University of Liège) and cancellous bone tissue of a deer antler (Faculty of Veterinary Medicine, University of Liège). [less ▲]

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See detailUse of X-ray microtomography to study the homogeneity of carbon nanotube aqueous suspensions and carbon nanotube/polymer composites
Haghgoo, M.; Plougonven, Erwan ULg; Yousefi, Ali Akbar et al

in Carbon (2012), 50(4), 1703-1706

X-ray microtomography was used to study the stability and homogeneity of concentrated carbon nanotube (CNT) aqueous suspensions and CNT/resorcinol–formaldehyde gel composites. Various CNT distribution ... [more ▼]

X-ray microtomography was used to study the stability and homogeneity of concentrated carbon nanotube (CNT) aqueous suspensions and CNT/resorcinol–formaldehyde gel composites. Various CNT distribution states were achieved by modifying the CNT concentration, sonication time and resting time. X-ray microtomography is able to discriminate between zones with different CNT concentration levels and can be used as a non-destructive and fast tool to characterize the homogeneity of suspensions and composite systems at the micron scale. [less ▲]

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See detailEffect of CO2 activation of carbon xerogels on the adsorption of methylene blue
Páez Martínez, Carlos ULg; Contreras, M. S.; Léonard, Angélique ULg et al

in Adsorption (2012), 18(3-4), 199-211

The effect of physical activation with CO2 of carbon xerogels, synthesized by pyrolysis of a resorcinolformaldehyde aqueous gel, on the adsorption capacities of Methylene Blue (MB) was studied. The ... [more ▼]

The effect of physical activation with CO2 of carbon xerogels, synthesized by pyrolysis of a resorcinolformaldehyde aqueous gel, on the adsorption capacities of Methylene Blue (MB) was studied. The activation with CO2 lead to carbon materials with micropore volumes ranging from 0.28 to 0.98 cm³/g -1 C. MB-adsorption isotherm studies showed that the increase of micropore volume and corresponding surface area led to: (i) a significant improvement in the capacity of MB-adsorption at monolayer coverage, from 212 to 714 mgg -1 C, and (ii) an increase of the binding energy related to Langmuir isotherm constant up to 45 times greater than those of commercial microporous activated carbons used as reference (NORIT R2030, CALGON BPL and CALGON NC35). It is proposed that the increase of the binding energy results from chemical cleaning of the O-groups onto carbon surface as a consequence of CO2-activation, increasing the π-π interaction between MB and graphene layers of the carbon xerogels. Finally, a series of batch kinetics were performed to investigate the effect of CO2-activation conditions on the mechanism of MB-adsorption. Experimental data were fitted using pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models. From pseudo-second-order kinetic model, one observes an increase in the initial rate of MB-adsorption from 0.019 to 0.0565 min -1, by increasing the specific surface area from 630 to 2180 m²/g -1 C via CO2-activation. Depending on the activation degree of the carbons, two different mechanisms control the MB-adsorption rate: (i) at low activation degree, the intraparticle diffusion is the rate-limiting phenomenon, whereas (ii) at high activation degree, the reactions occurring at the solid/liquid interface are the rate-limiting steps. © 2012 Springer Science+Business Media, LLC. [less ▲]

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See detailPhotodegradation of phenol and benzoic acid by sol-gel-synthesized alkali metal-doped ZnO
Benhebal, H.; Chaib, M.; Léonard, Angélique ULg et al

in Materials Science in Semiconductor Processing (2012), 15(3), 264269

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See detailMicro and macroscopic investigation to quantify tillage impact on soil hydrodynamic behaviour
Beckers, Eléonore ULg; Roisin, Chrsitian; Plougonven, Erwan ULg et al

in Geophysical Research Abstracts (2012), 14

Nowadays, tillage simplification is an increasing practice. Many advantages are cited in the literature, such as energy saving, soil conservation etc. Agricultural management practices influence soil ... [more ▼]

Nowadays, tillage simplification is an increasing practice. Many advantages are cited in the literature, such as energy saving, soil conservation etc. Agricultural management practices influence soil structure, but consequent changes in soil hydrodynamic behaviour at the field scale are still not well understood. Many studies focus only on macroscopic measurements which do not provide mechanistic explanations. Moreover, research shows divergent conclusions over structure modification. The aim of this work is to fill this gap by quantifying soil structure modification depending on tillage intensity through both macroscopic and microscopic measurements, the latter improving our comprehension of the fundamental mechanisms involved. [less ▲]

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