References of "Léonard, Angélique"
     in
Bookmark and Share    
Full Text
See detailAccurate measurement of radius evolution as a function of direction in 3D images
Plougonven, Erwan ULg; Hubert, Julien ULg; Collin, Frédéric ULg et al

Poster (2016, May 11)

Very often the reason for using of X-Ray tomography in a research project is to measure the evolution of some geometrical characteristic. The sought characteristic may be explained in simple words like ... [more ▼]

Very often the reason for using of X-Ray tomography in a research project is to measure the evolution of some geometrical characteristic. The sought characteristic may be explained in simple words like size, shape, or distance, but in practice measures based on these notions can have a complex implementation. We present a simple problem, measuring the evolution of radius in a cylindrical sample (a common shape for sample preparation for tomography) and how this value differs according the direction in which we look, when such evolution is known to be anisotropic. The solution is not unique, but we show that a naïve manual approach are not accurate enough, and how even a simple geometric notion such as radius needs a thorough definition in relation to its applicability to 3D image analysis. We extend the argument to how a good understanding of the notions and algorithms used in the quantification of geometrical characteristics can directly affect the pertinence and representativity of the results. [less ▲]

Detailed reference viewed: 21 (2 ULg)
Full Text
Peer Reviewed
See detailDrying induced shrinkage of Boom Clay: an experimental investigation
Prime, Noémie; Levasseur, Séverine; Miny, Laurent et al

in Canadian Geotechnical Journal (2016), 53(3), 396-409

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying ... [more ▼]

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying shrinkage. However, there is still a lack of knowledge concerning shrinkage evolution in time and shrinkage propagation within the material. In this study, the shrinkage of a specific clayey rock, Boom Clay, under drying conditions is experimentally investigated. This rock is a deep geological formation which is under study for high-level and long-life radioactive waste storage in Belgium. Two experimental campaigns are here presented. The first one, based on vapour equilibrium drying technique and completed by sample size manual measurement, aims to characterize the material shrinkage in balanced states. The second one, based on convective drying technique completed by shape monitoring using X-ray tomography, aims to analyse how shrinkage develops before reaching a steady state. Both approaches put in evidence the shrinkage anisotropy of this structurally bedded rock, with a ratio around 2 between the direction of maximum strains and the direction of minimum strains. However, the two drying techniques also provide complementary results, as the relation between the amount of shrinkage and the retention curve (for the uniform drying imposed with saline solutions) and the kinetics of shrinkage propagation inside the material (for the non-uniform drying imposed with air convection). [less ▲]

Detailed reference viewed: 84 (31 ULg)
Full Text
See detailDesiccation cracks formation in clay-barrier for nuclear waste disposal
Hubert, Julien ULg; Prime, Noémie; Plougonven, Erwan ULg et al

Conference (2016, February 16)

In geotechnical engineering, the desiccation cracking of soil is commonly observed. This phenomenon is detrimental to the behavior of earth material and earth structure. Desiccation cracks can lead to the ... [more ▼]

In geotechnical engineering, the desiccation cracking of soil is commonly observed. This phenomenon is detrimental to the behavior of earth material and earth structure. Desiccation cracks can lead to the overall failure of many geotechnical structures: • They can affect the slope stability of earth dams or embankments; • They can initiate internal erosion of embankments due to water flow through the cracks; • They can compromise the efficiency of soil barriers such as landfill liners and top covers. Nowadays, the storage of nuclear waste in deep impermeable geological layers is considered. These storages are based on the multi-barrier principle, the last of which being the host rock, typically a clayey material. In this context, maintaining the very low hydraulic conductivity of the host rock is crucial. Unfortunately, the ventilation of excavated galleries causes convective drying of the host material and can lead to crack formation. This work aims to understand in which conditions exactly, during convective drying, does cracking occur in clayey materials. An experimental campaign has been carried out to characterize the drying behavior of Boom clay which is the host rock at the underground research facility in Mol (Belgium). X-Ray micro-tomography has been used to analyze crack development as well as shrinkage. The experiments are used to calibrate the transfer parameters of a convective drying law based on the limit layer model. This calibration is based on agreement of the drying kinetics. A numerical study is then performed and aims at reproducing the behavior observed during the experiments. A thermo-hydro-mechanical coupled model is used to determine the stress distribution during the drying and a tensile failure criterion is suggested to predict crack genesis. Simulations are performed using the in-house built FEM code LAGAMINE. [less ▲]

Detailed reference viewed: 41 (4 ULg)
Full Text
Peer Reviewed
See detailDoes biobased polymer achieve better environmental impacts than fossil polymer? Comparison of fossil HDPE and biobased HDPE produced from sugar beet and wheat
Belboom, Sandra ULg; Léonard, Angélique ULg

in Biomass & Bioenergy (2016), 85

Polymers are one of the most used materials and the majority of their production is based on fossil fuels. Due to the decrease of oil resources and concerns about climate change, alternatives are needed ... [more ▼]

Polymers are one of the most used materials and the majority of their production is based on fossil fuels. Due to the decrease of oil resources and concerns about climate change, alternatives are needed, the transformation of biobased ethanol into biobased polymer being one of them. This paper undertakes an environmental evaluation of the production of biobased polymer produced from two different feedstock cultivated in Belgium: sugar beet and wheat. Both crops cultivation are studied as well as their transformation into biobased ethanol, first, and then to biobased ethylene, focusing on high-density polyethylene (HDPE) as final product. These scenarios are analyzed and compared with the production of conventional polymer using the life-cycle assessment (LCA) methodology with reference to relevant environmental impact categories. This study shows a reduction of impact of around 60% for both climate change and fossil fuel depletion categories when using biobased HDPE instead of its fossil counterpart. For all other impact categories, fossil HDPE achieves better results than the biobased product. [less ▲]

Detailed reference viewed: 52 (6 ULg)
Peer Reviewed
See detailLife cycle assessment of hybrid vehicles recycling: Comparison of three business lines of dismantling
Belboom, Sandra ULg; Lewis, Grégory; Bareel, Pierre-François et al

in Waste Management (2016), 50

This paper undertakes an environmental evaluation of hybrid vehicles recycling, using industrial data from Comet Traitement SA in Belgium. Three business lines have been modelled and analysed. The first ... [more ▼]

This paper undertakes an environmental evaluation of hybrid vehicles recycling, using industrial data from Comet Traitement SA in Belgium. Three business lines have been modelled and analysed. The first one is relative to the business as usual with a dismantling to recover batteries and engines followed by shredding and post shredding treatments. The second one considers, in addition, the removal of electronic control units (ECU) before shredding followed by same steps than in the first line and the last one is relative to the additional removal of big plastic parts before shredding and business as usual post shredding treatments. Results show non-significant environmental benefits when ECU or large parts of plastics are recovered before shredding. Improvements in terms of environmental benefits are lower than the uncertainty of the results. Indeed, the performing usual process for end-of-life vehicles (ELV) treatment reaches 97% of the ELV which is valorised in terms of metal and energy recoveries. Post shredding treatment units include metals, plastics and energy recovery of residues. Comet business as usual route for ELV valorisation is in accordance with the requirements of the European directive and recommendations for further improvement with dismantling of other parts (ECU or plastics) before shredding are non-relevant in this case. [less ▲]

Detailed reference viewed: 28 (12 ULg)
Peer Reviewed
See detailConvective drying behavior of sawdust-sludge mixtures in a fixed bed
Li, Jie; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

in Drying Technology (2016), 34(4), 395-402

Detailed reference viewed: 26 (9 ULg)
Peer Reviewed
See detailSludge dewatering and drying: about the difficulty of making experiments with a non-stabilized material
Pambou, Yvon-Bert ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

in Desalination and Water Treatment (2016), 57(30), 13841-13856

Detailed reference viewed: 63 (5 ULg)
Full Text
Peer Reviewed
See detailForced Convective Drying of Wastewater Sludge with Presentation of Exergy Analysis of the Dryer
Bennamoun, Lyes; Fraikin, Laurent ULg; Li, Jie et al

in Chemical Engineering Communications (2016), 203

The main objective is studying the fundamental aspect, by the mean of the drying kinetics, the application of forced convective drying of wastewater sludge with determination of the optimum drying ... [more ▼]

The main objective is studying the fundamental aspect, by the mean of the drying kinetics, the application of forced convective drying of wastewater sludge with determination of the optimum drying conditions. The drying system is composed of two units; small samples of 2.5 g are dried in the first unit and bed of sludge weighting 250 g is dried the second unit. The experiments are performed under air temperatures varying between 80°C and 200°C. The range of the air velocity and its humidity is 1- 2 m/s and 0.005- 0.05 kgwater/kgdry air, respectively. The experiments are performed for two different sludges; activated sludge (AS) and thermalized and digested sludge (TDS). Usually, three main drying phases are observed during drying of bed of sludge. These phases are reduced to only two for small samples. Determination of the influent parameters shows that temperature of the drying air and sludge origin can profoundly influence the drying kinetic of the sludge. The exergy analysis of the two units of the drying system allows selecting 140 °C, 2 m/s, 0.05 kgwater/kgdry air as optimum drying condition with an exergy efficiency reaching 90\%. [less ▲]

Detailed reference viewed: 29 (2 ULg)
Full Text
Peer Reviewed
See detailEnvironmental Impact Assessment of Rail Freight Intermodality
Merchan Arribas, Angel ULg; Belboom, Sandra ULg; Léonard, Angélique ULg

in Pombo, Joao (Ed.) The Third International Conference on Railway Technology: Research, Development and Maintenance (2016)

The European Commission’s White Paper on transport seeks to achieve an efficient and sustainable balance between the various transport modes. In this context, BRAIN-TRAINS is a project supported by ... [more ▼]

The European Commission’s White Paper on transport seeks to achieve an efficient and sustainable balance between the various transport modes. In this context, BRAIN-TRAINS is a project supported by Belgian Federal Government that deals with rail freight intermodality, approaching the problem from an interdisciplinary perspective. BRAIN-TRAINS will be able to answer the transition involved in transportation in Belgium. To analyse the sustainability impact of rail freight intermodality in Belgium, the life cycle assessment methodology will be used. The rail freight system is divided in this paper into rail operation, rail equipment and rail infrastructure. This paper shows the methodology to calculate the transport emissions related with the energy consumption during the rail operation. [less ▲]

Detailed reference viewed: 25 (10 ULg)
Full Text
Peer Reviewed
See detailExperimental and computational micro–mechanical investigations of compressive properties of polypropylene/multi–walled carbon nanotubes nanocomposite foams
Wan, Fangyi; Tran, Minh Phuong; Leblanc, Christophe ULg et al

in Mechanics of Materials (2015), 91(Part 1), 95-118

The compressive behavior of nanocomposite foams is studied by both experimental and computational micro-mechanics approaches with the aim of providing an efficient computational model for this kind of ... [more ▼]

The compressive behavior of nanocomposite foams is studied by both experimental and computational micro-mechanics approaches with the aim of providing an efficient computational model for this kind of material. The nanocomposites based on polypropylene (PP) and different contents of multi-walled carbon nanotubes (CNTs) are prepared by melt mixing method. The nanocomposite samples are foamed using super-critical carbon dioxide (ScCO2) as blowing agent at different soaking temperatures. The influence of this foaming parameter on the morphological characteristics of the foam micro-structure is discussed. Differential Scanning Calorimetry (DSC) measurements are used to quantify the crystallinity degree of both nanocomposites and foams showing that the crystallinity degree is reduced after the foaming process. This modification leads to mechanical properties of the foam cell walls that are different from the raw nanocomposite PP/CNTs material. Three--point bending tests are performed on the latter to measure the flexural modulus in terms of the crystallinity degree. Uniaxial compression tests are then performed on the foamed samples under quasi-static conditions in order to extract the macro-scale compressive response. Next, a two-level multi-scale approach is developed to model the behavior of the foamed nanocomposite material. On the one hand, the micro-mechanical properties of nanocomposite PP/CNTs cell walls are evaluated from a theoretical homogenization model accounting for the micro-structure of the semi-crystalline PP, for the degree of crystallinity, and for the CNT volume fraction. The applicability of this theoretical model is demonstrated via the comparison with experimental data from the described experimental measurements and from literature. On the other hand, the macroscopic behavior of the foamed material is evaluated using a computational micro-mechanics model using tetrakaidecahedron unit cells and periodic boundary conditions to estimate the homogenized properties. The unit cell is combined with several geometrical imperfections in order to capture the elastic collapse of the foamed material. The numerical results are compared to the experimental measurements and it is shown that the proposed unit cell computational micro-mechanics model can be used to estimate the homogenized behavior, including the linear and plateau regimes, of nanocomposite foams. [less ▲]

Detailed reference viewed: 185 (61 ULg)
Full Text
Peer Reviewed
See detailEnvironmental impacts of phosphoric acid production using di-hemihydrate process: a Belgian case study
Belboom, Sandra ULg; Szöcs, Carl; Léonard, Angélique ULg

in Journal of Cleaner Production (2015), 108

This paper undertakes an environmental evaluation of phosphoric acid production, using industrial data from Prayon SA in Belgium. Phosphoric acid is produced using the wet di-hemihydrate process also ... [more ▼]

This paper undertakes an environmental evaluation of phosphoric acid production, using industrial data from Prayon SA in Belgium. Phosphoric acid is produced using the wet di-hemihydrate process also called Central Prayon process. Both grades of phosphoric acid are evaluated: fertilizer and purified grades. Specificities of this plant are highlighted and improvements of the process in terms of energy and facilities integration through years are quantified as environmental benefits. The implementation on site of two sulphuric acid production facilities and their energetic integration allow a reduction of climate change impact of 80%. Results also show the importance of phosphogypsum valorisation which is sold for the main part in this case study. Concerning the purified grade, this specific process has been compared to the thermal process, using Best Available Techniques (BAT) values for the modelling. It shows a reduced environmental impact for the wet process in the majority of categories studies. [less ▲]

Detailed reference viewed: 67 (3 ULg)
Full Text
See detailL’empreinte environnementale des pierres ornementales? Pour qui, pourquoi, comment?
Belboom, Sandra ULg; Renzoni, Roberto ULg; Tourneur, Francis ULg et al

Conference (2015, October 22)

Dans les matériaux de construction, la notion d’environnement et d’empreinte des produits devient de plus en plus importante que ce soit dans un cadre législatif ou comme objet de marketing. Dans ce ... [more ▼]

Dans les matériaux de construction, la notion d’environnement et d’empreinte des produits devient de plus en plus importante que ce soit dans un cadre législatif ou comme objet de marketing. Dans ce contexte, des études environnementales ont été réalisées sur divers produits belges en pierre bleue (dalles, bordures, marches) ainsi qu’en grès (pavés). Ces études ont été menées en utilisant la méthodologie de l’Analyse du Cycle de Vie (ACV) et ont permis de mettre en évidence les étapes prépondérantes de leur production dans une optique d’écoconception ainsi que de les comparer à d’autres produits sur le marché tels que leurs concurrents asiatiques. Les frontières du système comprennent les étapes depuis l’extraction des matières premières, en passant par la production des produits finis ainsi que leur transport sur chantier situé en Belgique. Cette présentation reprend le pourquoi et le comment d’une Analyse du Cycle de Vie, les différentes étapes nécessaires à l’application de l’ACV aux produits en pierre belge ainsi que les principaux résultats. Cette présentation permettra la mise en évidence de l’intérêt de l’ACV et des fiches de déclaration environnementale qui y sont associées ainsi que les perspectives qui peuvent en découler dans le domaine des matériaux et plus précisément pour les matières minérales. [less ▲]

Detailed reference viewed: 24 (1 ULg)
Peer Reviewed
See detailEffet du taux de dopage sur l'activité photocatalytique de ZnO dopé par les métaux alcalins
Benhebal, Hadj; Benrabah, Boulem; Léonard, Angélique ULg et al

Conference (2015, October 16)

Detailed reference viewed: 32 (3 ULg)
Full Text
Peer Reviewed
See detailEnvironmental impact assessment of bio-based binders: from production to industrial applications
Gerbinet, Saïcha ULg; Belboom, Sandra ULg; Briard, Vincent et al

Poster (2015, October 15)

A binder is used to hold together the fibers forming the mineral wool products (see figure 1). These fibers can be produced from sand and recycled glass for glass wool products (see figure 2) or from rock ... [more ▼]

A binder is used to hold together the fibers forming the mineral wool products (see figure 1). These fibers can be produced from sand and recycled glass for glass wool products (see figure 2) or from rock (volcanic rock, typically basalt or dolomite) for stone wool products. Traditionally, the binders used in mineral wool products are based on phenol-formaldehyde. Due to sanitary and environmental considerations and increased focus on indoor air quality, the producers developed new alternative binders. Especially, Knauf Insulation, a worldwide building insulation manufacturer, developed a binder based on plant starch and called ECOSE. In addition of not using added phenol-formaldehyde , this new binder is also supposed to reduce the environmental impacts of Knauf Insulation mineral wools. Moreover, due to its properties, others applications are now considered for ECOSE such as composite wood panels [1]. The aim of this study is to determine the environmental impact of ECOSE and to compare it with more traditional binders using Life Cycle Assessment (LCA) methodology. LCA analyzes the environmental aspects and potential impacts associated with all the stages of a product's life. In this type of environmental assessment the energy and material flows for the entire life-cycle are surveyed and analyzed with special attention to possible environmental hazards or human health problems. The ISO 14040 and 14044 norms [2, 3] provide the general guidance for performing an LCA. The LCA methodology is first applied to ECOSE main component: glucose. The presentation will present results for glucose production from cereals starches After that, first ECOSE application, glass mineral wool products will be presented in details, including production process (see figure 3). The modelling of the glass mineral wool production process in LCA software GaBi 6 [4] is then described. One of the model specificity is that it allows to perform LCA of any glass wool products produced in Knauf Insulation plants in Europe. The adaptations to the model to allow studying former glass wool product when using phenol-formaldehyde binders will also be presented such as the advantages of this model. Moreover, preliminary results about ECOSE and phenol-formaldehyde glass wool products are explained. Références [1] Knauf Insulation. [cited 2014; Available from: http://www.knaufinsulation.ua/en. [2] ISO 14044, Environmental management - Life cycle assessment - Requirements and guidelines. 2006. [3] ISO 14040, Environmental management - Life cycle assessment - Principles and framework. 2006. [4] LBP, University of Stuttgart, and PE INTERNATIONAL AG, GaBI 6. 2012: Leinfelden-Echterdingen. p. GaBi 6: Software and database for life cycle engineering. [less ▲]

Detailed reference viewed: 46 (1 ULg)