References of "Léonard, Angélique"
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See detailBaker's yeast behavior during vacuum agitated contact drying
Bennamoun, Lyes ULg; Afzal, Muhammad; Léonard, Angélique ULg

in Chemical Engineering and Technology (2013), 36(10), 1795-1800

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See detailDifferent phases of water transfer during rock drying
Prime, Noémie ULg; Housni, Zakarya; Fraikin, Laurent ULg et al

Conference (2013, September 10)

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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 ULg; Collard, Valérie ULg et al

in Procedia Engineering (2013, September 02)

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. [less ▲]

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See detailHeat and mass transfer coefficient analysis during rock convective drying
Prime, Noémie ULg; Housni, Zakarya; Fraikin, Laurent ULg et al

Conference (2013, August)

This paper presents some experimental investigations about convective drying of rocks. Cylindrical samples made of limestone are dried from one their bases submitted to an air flow, while the other ... [more ▼]

This paper presents some experimental investigations about convective drying of rocks. Cylindrical samples made of limestone are dried from one their bases submitted to an air flow, while the other surfaces are hermetically covered. All other factors being equal, the influence of two parameters is looked after: the cylinder height, equivalent to the volume/surface ratio of the samples, and the direction of the air flow. The tests are interpreted both from the drying curves and from the values of water and heat transfer coefficients. Results first highlight that air flow incidence on the dried surface changes the kinetics and the transfer coefficient values. It can thus be supposed that the air flow direction would modify the thickness of the transfer limit layer at the surface and/or would make invalid the hypothesis of such a limit layer model for some flow configurations. Besides, the volume/surface ratio is shown to be correlated to the evaporation flux on the constant drying phase, and thus to the transfer coefficients. Nonetheless, this link tends to disappear from sufficiently high values of the volume/surface ratio since, in this case, the transfer coefficients reach constant values. This effect, in addition to other observations made on the drying curves, well fits with the hypothesis of a hydraulically connected layer below the drying surface, which would maintain during the constant drying rate phase. In the present case, this layer would have a thickness of around 20 to 30 mm. [less ▲]

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See detailConvective drying of wastewater sludge: Introduction of shrinkage effect in mathematical modeling
Bennamoun, Lyes ULg; Crine, Michel ULg; Léonard, Angélique ULg

in Drying Technology (2013), 31(6), 643-654

Drying of two kinds of wastewater sludge was studied. The first part was an experimental work done in a discontinuous cross-flow convective dryer using 1 kg of wet material extruded in 12-mm-diameter ... [more ▼]

Drying of two kinds of wastewater sludge was studied. The first part was an experimental work done in a discontinuous cross-flow convective dryer using 1 kg of wet material extruded in 12-mm-diameter cylinders. The results show the influence of drying air temperature for both sludges. The second part consisted of developing a drying model in order to identify the internal diffusion coefficient and the convective mass transfer coefficient from the experimental data. A comparison between fitted drying curves, well represented by Newton's model, and the analytical solutions of the equation of diffusion, applied to a finite cylinder, was made. Variations in the physical parameters, such as the mass, density, and volume of the dried product, were calculated. This allowed us to confirm that shrinkage, which is an important parameter during wastewater sludge drying, must be taken into account. The results showed that both the internal diffusion coefficient and convective mass transfer coefficient were affected by the air temperature and the origin of the sludge. The values of the diffusion coefficient changed from 42.35 × 10−9 m2 · s−1 at 160°C to 32.49 × 10−9 m2 · s−1 at 122°C for sludge A and from 33.40 × 10−9 m2 · s−1 at 140°C to 28.45 × 10−9 m2 · s−1 at 120°C for sludge B. The convective mass transfer coefficient changed from 4.52 × 10−7 m · s−1 at 158°C to 3.33 × 10−7 m · s−1 at 122°C for sludge A and from 3.44 × 10−7 m · s−1 at 140°C to 2.84 × 10−7 m2 · s−1 at 120°C for sludge B. The temperature dependency of the two coefficients was expressed using an Arrhenius-type equation and related parameters were deduced. Finally, the study showed that neglecting shrinkage phenomena resulted in an overestimation that can attain and exceed 30% for the two coefficients. [less ▲]

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

Conference (2013, April 25)

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See detailL’Analyse du Cycle de vie : quoi, pourquoi, comment ?
Léonard, Angélique ULg

Scientific conference (2013, March 22)

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See detailACV et Ecoconception: illustration de la démarche au sein de Knauf Insulation.
Gerbinet, Saïcha ULg; Briard, Vincent; Léonard, Angélique ULg

Conference (2013, March 22)

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See detailDetermination of Moisture Diffusivity During Drying of Mortar Cement: Experimental and Modeling Study
Bennamoun, Lyes ULg; Kahlerras, Loubna ULg; Michel, Frédéric ULg et al

in International Journal of Energy Engineering (2013), 3(1), 1-6

The aim of this study is the experimental characterization of the behaviour of a mortar during convective drying. We focalise on mortar that has a rate water-cement of 0.5. The drying tests are developed ... [more ▼]

The aim of this study is the experimental characterization of the behaviour of a mortar during convective drying. We focalise on mortar that has a rate water-cement of 0.5. The drying tests are developed in a micro-convective dryer that can use samples weighing from 0 to 8g. The advantage of these experiments is to reproduce the natural conditions that can be found during the treatment of the mortar-atmosphere problems. The response of the drying curve or the drying kinetic depends on the applied drying conditions. So, the temperature of the air varies from 60°C to 130°C, the velocity of the air is changed from 2 m.s-1 to 5 m. s-1and the relative humidity is kept less than 1.7%. The comparison between the experimental results and the proposed analytical solutions of the equation of diffusion represented by Fick’s law, applied for a finite shape, allows determination of the values of the diffusion coefficient. It has a value of 1.71×10-10 m2.s-1 at 60°C, 13.69×10-10 m2.s-1 at 90°C and 16.27×10-10 m2.s-1 at 130°C. Calculation of the activation energy and the D0 constant are also possible. [less ▲]

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See detailThe effect of collagenated space filling materials in sinus bone augmentation: a study in rabbits
LAMBERT, France ULg; Léonard, Angélique ULg; Drion, Pierre ULg et al

in Clinical Oral Implants Research (2013), 24(5),

Aim: The inclusion of biomaterial particles used for alveolar bone regeneration in a carrier or in binding agents such as collagen gel or fibers is of interest as a means to help with surgical handling ... [more ▼]

Aim: The inclusion of biomaterial particles used for alveolar bone regeneration in a carrier or in binding agents such as collagen gel or fibers is of interest as a means to help with surgical handling. However, the possible influence of collagen on bone tissue response to biomaterials is poorly studied. The objective of the present study was to investigate, in a sub-sinus bone augmentation model in rabbits, the effect of collagen at different stages of the osteogenesis process. Histologic, histomorphometric and volumetric analyses were performed. Materials and methods: Rabbits underwent a double sinus lift procedure using bovine hydroxyapatite (BHA), collagenated bovine hydroxyapatite (BHAColl), and prehydrated and collagenated porcine hydroxyapatite (PHAColl). Animals were sacrificed at 1 week, 5 weeks or 6 months. Samples were subjected to X-ray micro-tomography and histology. Qualitative analysis was performed on the non-decalcified sections and quantitative histomorphometric analyses were conducted using scanning electron microscopy (SEM). Volume variations of bone augmentations were calculated at different time points. Results: The three biomaterials allowed an optimal bone formation and were able to equally withstand sinusal reexpansion. A comparable percentage of new bone, as well as 3D volume stability, was found between the groups at each time point. However, the PHAColl resorption rate was significantly higher than the rates in other groups (P = 0.0003), with only 3.6% of the particles remaining at 6 months. At 1 week, both collagenated groups displayed the presence of inflammatory cells although BHA did not show any sign of inflammation. At 5 weeks and 6 months, the inflammatory process had disappeared completely in the BHAColl groups, whereas some inflammatory-like cells could still be observed around the remaining particles of PHAColl. Conclusions and clinical implications: Within the limitations of this study in rabbits, the findings showed the presence of inflammatory-like cells at the early stage of bone regeneration when collagenated xenogenic biomaterials were used compared to xenogenic granules alone. Nevertheless, similar bone formation occurred and comparable 3D volumes were found at 6 months in the different groups. [less ▲]

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See detailBone Regeneration Using Porous Titanium Particles versus Bovine Hydroxyapatite: A Sinus Lift Study in Rabbits.
LAMBERT, France ULg; LECLOUX, Geoffrey ULg; Léonard, Angélique ULg et al

in Clinical Implant Dentistry & Related Research (2013), 15(3),

Aim: The first objective of this study was to qualitatively and quantitatively assess the bone formation process, particularly the long-term behavior and three-dimensional volume stability of subsinusal ... [more ▼]

Aim: The first objective of this study was to qualitatively and quantitatively assess the bone formation process, particularly the long-term behavior and three-dimensional volume stability of subsinusal bone regeneration, using titanium (Ti) or bovine hydroxyapatite (BHA) granules, in a rabbit model. The second objective was to evaluate the effect of the hydration of the BHA particles with a therapeutic concentration of doxycycline solution on the osteogenesis and biomaterial resorption. Materials and Methods: Rabbits underwent a double sinus lift procedure using one of three materials: grade 1 porous Ti particles, BHA, or BHA hydrated with doxycycline solution (0.1 mg/ml) (BHATTC). Animals were sacrificed after 1 week, 5 weeks, or 6 months. Samples were analyzed using µCT and nondecalcified histology. Results: The materials used in each of the three groups allowed an optimal bone formation; bone quantities and densities were not statistically different between the three groups. At 6 months, more stable three-dimensional volume stability was found with Ti and BHATTC (p = .0033). At 5 weeks and 6 months, bone to material contact corroborating osteoconduction was significantly higher with BHA and BHATTC than with Ti (p < .0001). Conclusions and Clinical Implications: Even though the studied biomaterials displayed different architectures, they are relevant candidates for sinus lift bone augmentation prior to dental implants because they allow adequate three-dimensional stability and osteogenesis. However, to recommend the clinical use of Ti, both an observation on the drilling effects of Ti particles and clinical trials are needed. [less ▲]

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See detailA comparison of three calcium phosphate based space fillers in sinus elevation: a study in rabbits
LAMBERT, France ULg; Léonard, Angélique ULg; LECLOUX, Geoffrey ULg et al

in The international Journal of Oral and Maxillofacial Implants (2013), 28(2), 393-402

Aim: Sub-sinusal bone regeneration procedures are reliable procedures that are known to be efficient with the use of biomaterials alone. Nevertheless, many types of biomaterials are available, and their ... [more ▼]

Aim: Sub-sinusal bone regeneration procedures are reliable procedures that are known to be efficient with the use of biomaterials alone. Nevertheless, many types of biomaterials are available, and their efficacy in terms of bone formation and resorption rate have rarely been compared. This study aimed to compare the bone formation, resorption rate, osteoconductivity and 3D volume changes of three biomaterials often used for alveolar ridge augmentation. Materials and Methods: Rabbits underwent a double sinus lift procedure using three different types of space fillers: bovine hydroxyapatite (BHA), beta calcium phosphate (ß-TCP) and biphasic calcium phosphate (BCP). Animals were sacrificed at 1 week, 5 weeks and 6 months. Samples were subjected to X-ray microtomography and histology. Qualitative analysis was performed on non-decalcified sections, and quantitative histomorphometric analysis was conducted using SEM. Volume variations of bone augmentations were calculated at different time points. Results: All three particulated biomaterials proved to be effective in promoting osteogenesis. At 6 months, biomaterial resorption rates were significantly different across the 3 groups (p<0.0001). The highest resorption rate was found with β-TCP, in which only 6.7% of the baseline particle surface remained. At 6 months, bone was in close contact with the BHA particles, constituting a composite network; in contrast, BCP particles were often surrounded by soft tissues. In each group, no significant difference in volume variations were found at the different time point. Conclusions and clinical implications: Despite the limitations of the study, the three particulated space-filling biomaterials proved to be efficient to promote osteogenesis. High resorption rates and complete replacement of the biomaterials by bone seemed to withstand intrasinusal pressure. Further investigations in humans should consider longer follow-up periods. [less ▲]

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See detailSol-gel preparation and characterisation of SnO2 powders employed as catalyst for phenol photodegradation
Benhebal, Hadj; Chaib, Messaoud; Léonard, Angélique ULg et al

in Scientia Iranica (2013), 20(6), 1891-1898

Crystallized pure SnO2 powders were prepared by the sol-gel process and were used as photocatalyst for the degradation of phenol under UV light at pH 6.5 and a temperature of 20°C. The physical properties ... [more ▼]

Crystallized pure SnO2 powders were prepared by the sol-gel process and were used as photocatalyst for the degradation of phenol under UV light at pH 6.5 and a temperature of 20°C. The physical properties of photocatalyst were characterized by X-ray diffraction, Scanning Electron Microscopy, nitrogen adsorption-desorption and Ultraviolet-visible diffuse reflectance spectroscopy. The influences of different operating variables such as the pH, the photocatalyst loading, the initial concentration of phenol, were studied to improve the efficiency of phenol degradation. [less ▲]

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See detailPhotocatalytic degradation of phenol and benzoic acid using zinc oxide powders prepared by the sol-gel process
Benhebal, Hadj; Chaib, Messaoud; Salmon, Thierry ULg et al

in Alexandria Engineering Journal (2013), 52(3), 517-523

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray ... [more ▼]

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray diffraction and transmission electron microscopy. The Brunauer–Emmett–Teller surface area, pHpzc, and the band gap of the catalyst samples were also measured. The influence of various key parameters such as amount of photocatalyst, initial solution pH, and the initial concentration of phenol and benzoic acid was investigated. [less ▲]

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See detailPhotocatalytic degradation of phenol and benzoic acid using zinc oxide powders prepared by the sol-gel process
Benhebal, Hadj; Chaib, Messaoud; Salmon, Thierry ULg et al

in Alexandria Engineering Journal (2013), 52(3), 517-523

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray ... [more ▼]

Photocatalytic degradation of phenol and benzoic acid in aqueous solution was studied using zinc oxide (ZnO) powder synthesized by sol–gel process. Synthesized catalyst was characterized by X-ray diffraction and transmission electron microscopy. The Brunauer–Emmett–Teller surface area, pHpzc, and the band gap of the catalyst samples were also measured. The influence of various key parameters such as amount of photocatalyst, initial solution pH, and the initial concentration of phenol and benzoic acid was investigated. [less ▲]

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See detailComparing technologies for municipal solid waste management using life cycle assessment methodology: a Belgian case study
Belboom, Sandra ULg; Digneffe, Jean-Marc; Renzoni, Roberto ULg et al

in International Journal of Life Cycle Assessment (2013), 18(8), 1513-1523

Purpose The present study aims at identifying the best practice in residual municipal solid waste management using specific data from Liège, a highly industrialized and densely populated region of Belgium ... [more ▼]

Purpose The present study aims at identifying the best practice in residual municipal solid waste management using specific data from Liège, a highly industrialized and densely populated region of Belgium. We also illustrate the importance of assumptions relative to energy through sensitivity analyses and checking uncertainties regarding the results using a Monte Carlo analysis. Methods We consider four distinct household waste management scenarios. A life cycle assessment is made for each of them using the ReCiPe method. The first scenario is sanitary landfill, which is considered as the base case. In the second scenario, the refuse-derived fuel fraction is incinerated and a sanitary landfill is used for the remaining shredded organic and inert waste only. The third scenario consists in incinerating the whole fraction of municipal solid waste. In the fourth scenario, the biodegradable fraction is collected and the remaining waste is incinerated. The extracted biodegradable fraction is then treated in an anaerobic digestion plant. Results and discussion The present study shows that various scenarios have significantly different environmental impact. Compared to sanitary landfill, scenario 4 has a highly reduced environmental impact in terms of climate change and particulate matter formation. An environmental gain, equal to 10, 37, or 1.3 times the impact of scenario 1 is obtained for, respectively, human toxicity, mineral depletion, and fossil fuel depletion categories. These environmental gains are due to energetic valorization via the incineration and anaerobic digestion. Considering specific categories, greenhouse gas emissions are reduced by 17 % in scenario 2 and by 46 % in scenarios 3 and 4. For the particulate matter formation category, a 71 % reduction is achieved by scenario 3. The figures are slightly modified by the Monte Carlo analysis but the ranking of the scenarios is left unchanged. Conclusions The present study shows that replacing a sanitary landfill by efficient incineration significantly reduces both emissions of pollutants and energy depletion, thanks to electricity recovery. [less ▲]

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