http://hdl.handle.net/2268/89 Search this channel search http://orbi.ulg.ac.be/simple-search http://hdl.handle.net/2268/148611 Title: Photobioreactors for efficient production of molecules with high added value, based upon an innovative technology for the production of porous materials <br/> <br/>Author, co-author: Tocquin, Pierre Thu, 16 May 2013 19:13:52 GMT http://hdl.handle.net/2268/148405 Title: Présentation d'un cas de corrosion microbienne dans la station d’épuration de Liège-Oupeye <br/> <br/>Author, co-author: Lecomte-Beckers, Jacqueline; Tchuindjang, Jérôme Tchoufack; Paydas, Hakan Mon, 13 May 2013 14:38:18 GMT http://hdl.handle.net/2268/148363 Title: Electroinitiated polymerization <br/> <br/>Author, co-author: Jérôme, Christine <br/> <br/>Abstract: Electroinitiated polymerization, a method particularly relevant in coating technology, offers the unique opportunity of imparting permanent functionality/reactivity to a variety of surfaces, provided that the solid substrate is (semi)conducting. By focusing on the electroinitiation of acrylic monomers, basic concepts and some tools dedicated to the analysis of this peculiar polymerization process are discussed in this chapter. The important role of this polymerization method in the field of conjugated polymers is also highlighted. Finally, this chapter concludes with the opportunities and future challenges of this technology. Mon, 13 May 2013 11:46:15 GMT http://hdl.handle.net/2268/147765 Title: A two-scale model predicting the mechanical behavior of nanocrystalline solids <br/> <br/>Author, co-author: Péron-Lührs, Vincent; Jérusalem, Antoine; Sansoz, Frédéric; Stainier, Laurent; Noels, Ludovic <br/> <br/>Abstract: Polycrystalline materials, with nanosized grains (<100 nm), exhibit superior strength exceeding those of their coarse-grained counterparts. With such small grains, the deformation mechanisms taking place at grain boundaries (GBs) become dominant compared to the intragranular crystal plasticity. Recent studies have revealed that the deformation mechanisms are influenced by the GB network. For instance, a high yield stress in nanostructured metals can be obtained by choosing the relevant grain boundary character distribution (GBCD). In this paper we present an original numerical multiscale approach to predict the mechanical behavior of nanostructured metals according to their GBCD composed of either high angle (HA) GBs (HAB) or low angle (LA) GBs (LAB). Molecular simulations using the quasicontinuum method (QC) are performed to obtain the mechanical response at the nanoscale of GB undergoing simple shear (GB sliding behavior) and tensile loads (GB opening behavior). To simulate the grain behavior, a mechanical model of dislocation motions through a forest dislocation is calibrated using a nanoindentation simulation performed with QC. These QC results are then used in a finite element code (direct numerical simulation-DNS) as a GB constitutive model and as a grain constitutive model. This two-scale framework does not suffer from length scale limitations conventionally encountered when considering the two scales separately. Thu, 02 May 2013 07:37:52 GMT http://hdl.handle.net/2268/147251 Title: Modified TiO2-based Photocatalytic Films and Powders produced by Aqueous and Non-Aqueous Sol-Gel Processes for Water Purification <br/> <br/>Author, co-author: Malengreaux, Charline <br/> <br/>Abstract: Summary Two major research goals have been proposed for this thesis. The first goal concerns the development of photocatalysts in the shape of thin films coated on glass substrates which includes (i) the development of a sol-gel chemistry suitable for the production of stable colloidal suspensions of TiO2 particles, (ii) the optimization of the deposition method and (iii) the development of an experimental device to measure the photocatalytic activity of the films. The second objective is the development of innovative non-aqueous and aqueous sol-gel routes, including the development of new methods for the introduction of dopants as well as the photocatalytic testing of the resulting materials. Two original non-aqueous sol-gel processes involving respectively, an in situ production of water and the controlled addition of a small amount of water, have been developed to produce a series of stable colloidal suspensions of TiO2 particles (sols). From those sols, transparent, adherent, homogeneous thin films have been produced using an optimized dip-coating deposition method and have been proven to be photocatalytically active for the degradation of an organic pollutant in aqueous solution. The photocatalytic activity of the films has been improved through an increase of their roughness thanks to the addition of an organic additive into the sol, leading to an increased active surface involved into the photocatalytic reaction. A mathematical model allowing the rigorous evaluation of the kinetic parameters of the photocatalytic reaction taking into account the influence of the variation of the volume inside the batch photoreactor has been developed. The equations have been established in the case of a photocatalytic powder homogeneously dispersed in the pollutant solution, and in the case of a photocatalytic thin film placed at the bottom of the reactor. The particular case of a first order reaction has been treated and the error on the reaction rate constant induced by neglecting the volume variation has been quantified. An environmentally-friendly aqueous sol-gel process for producing undoped and Cu2+, Ni2+, Zn2+, Pb2+, Fe3+, Cr3+, La3+ or Eu3+ single-doped as well as La3+- Fe3+ and Eu3+- Fe3+ co-doped TiO2 bulk photocatalysts composed of nanocrystallites of anatase and exhibiting a remarkably high photocatalytic activity without requiring any calcination step has been developed. Different effects of the metal ion dopant on the photocatalytic activity have been observed and discussed according to the dopant nature and content. A kinetic study of the photocatalytic degradation of a model pollutant (4-nitrophenol) in aqueous solution under UV-Visible light (330 nm < λ < 800 nm) has been performed over a promising TiO2-Zn2+ doped catalyst. Statistical validations have confirmed the suitability of the phenomenological reaction rate model developed to represent the 4-nitrophenol photocatalytic degradation over time.; Résumé Deux objectifs majeurs ont été proposés dans le cadre de cette thèse. Le premier objectif concerne le développement de photocatalyseurs sous forme de films déposés sur des supports de verre ce qui implique (i) le développement d’une chimie sol-gel permettant la production de suspensions colloïdales stables de particules de TiO2, (ii) l’optimisation de la méthode de dépôt et (iii) le développement d’un dispositif expérimental permettant de mesurer l’activité photocatalytique des films. Le second objectif proposé est le développement de procédés aqueux et non-aqueux, ainsi que de nouvelles méthodes permettant l’introduction de dopants, afin d’obtenir des photocatalyseurs innovants sous forme de poudres. Deux procédés sol-gel non-aqueux impliquant une production d’eau in situ ou l’addition contrôlée d’une faible quantité d’eau dans le système réactionnel ont été développés afin d’obtenir des suspensions colloïdales stables de particules de TiO2 (sols). L’utilisation de ces sols stables a permis la production de films minces transparents, adhérents et homogènes au moyen d’un procédé de dépôt par dip-coating optimisé. Les films obtenus permettent la dégradation photocatalytique de polluants organiques en milieu aqueux. L’introduction d’une molécule organique au cours de la synthèse a permis l’amélioration de l’activité photocatalytique des films grâce à un accroissement de leur rugosité, entrainant une augmentation de la surface active de catalyseur déposé par unité de surface de support. Un modèle mathématique permettant l’évaluation rigoureuse des paramètres cinétiques de la réaction photocatalytique en tenant compte de la variation de volume au sein du réacteur discontinu a été développé. Les équations ont été établies d’une part, dans le cas d’une poudre photocatalytique dispersée de manière homogène dans la solution de polluant et d’autre part, dans le cas d’un film photocatalytique déposé au fond du réacteur discontinu. Le cas particulier d’une réaction de premier ordre a été examiné. L’erreur sur la valeur de la constante cinétique induite en négligeant la variation de volume au sein du réacteur discontinu a été quantifiée. Un procédé sol-gel respectueux de l’environnement permettant la production de catalyseurs de TiO2 purs et dopés sous forme de poudres a été développé. Les ions Cu2+, Ni2+, Zn2+, Pb2+, Fe3+, Cr3+, La3+ et Eu3+ ont été utilisés comme dopant et co-dopant dans le cas des ions La3+-Fe3+ et Eu3+-Fe3+. Ce procédé aqueux permet d’obtenir des catalyseurs composés de nanocrystallites d’anatase présentant une activité photocatalytique remarquablement élevée sans nécessiter de traitement à haute température. Enfin, une étude cinétique de la dégradation photocatalytique d’un polluant modèle (4-nitrophenol) en milieu aqueux et sous lumière UV-Visible (330 nm < λ < 800 nm) a été réalisée avec un catalyseur TiO2 dopé en ions Zn2+. Une analyse statistique des résultats a permis de valider que le modèle cinétique phénoménologique proposé peut être utilisé pour représenter les données dans tout le domaine expérimental étudié. Tue, 23 Apr 2013 11:51:07 GMT http://hdl.handle.net/2268/147146 Title: One-pot controlled synthesis of double thermoresponsive N-vinylcaprolactam-based copolymers with tunable LCSTs <br/> <br/>Author, co-author: Kermagoret, Anthony; Fustin, Charles-André; Bourguignon, Maxime; Detrembleur, Christophe; Jérôme, Christine; Debuigne, Antoine <br/> <br/>Abstract: N-Vinylcaprolactam (NVCL) was copolymerized statistically for the first time in a controlled manner with hydrophilic N-vinylamide or hydrophobic vinylester monomers in order to precisely tune up and down the lower critical solution temperature (LCST) of the resulting copolymers. The incorporation of these segments in complex architectures was also considered. Several narrowly distributed NVCL-based copolymers were prepared by cobalt-mediated radical polymerization (CMRP) using the bis-(acetylacetonato)cobalt(II) complex as a controlling agent and N-methyl-N-vinylacetamide (NMVA), N-vinylacetamide (NVA), vinyl acetate (VAc) or vinyl pivalate (VPi) as comonomers. PNVCL-containing block copolymers having two discrete LCSTs were also synthesized following a one-pot strategy based on the sequential CMRP of NVCL followed by the copolymerization of NMVA with the residual NVCL. Upon gradual heating of aqueous solutions of such double thermoresponsive copolymers, we noticed a transition from free chains to micelles before full dehydration and collapse of the block copolymers. These advances represent a significant step towards the development of a platform based on thermoresponsive PNVCL copolymers with a single phase separation or multistep assembly behaviors. Fri, 19 Apr 2013 13:39:43 GMT http://hdl.handle.net/2268/147138 Title: The fracture studies of polycrystalline silicon based MEMS <br/> <br/>Author, co-author: Mulay, Shantanu Shashikant; Becker, Gauthier; Vayrette, Renaud; Raskin, Jean-Pierre; Pardoen, Thomas; Galceran, Montserrat; Godet, Stéphane; Noels, Ludovic <br/> <br/>Abstract: The advantages of micro-electro-mechanical systems (MEMS), such as low power requirement, miniaturized sizes and costs reduction, have already made significant impact in many technological fields. MEMS are now widely used as accelerometers, pressure sensors, and resonators etc. However, the determination of the mechanical properties of MEMS devices with high accuracy is still a challenging task due to their small dimensions and often anisotropic behaviour. This paper focuses on the modelling and simulation of the fracture of a key MEMS component, which is a polycrystalline silicon beam, by discontinuous Galerkin (DG) formulation combined with an extrinsic cohesive law (ECL) to describe the fracture process. As the beam is modelled by plane-stress 2D elements, an analytical equation to compute the effective fracture strength and the effective critical strain energy release rate in terms of the through-the-thickness fracture mode and of the orientation of the facet with respect to the crystal is also developed. At the end, a model is simulated, and the results are verified as per the physics of the problem and experiments. Fri, 19 Apr 2013 11:09:52 GMT http://hdl.handle.net/2268/147131 Title: Research on durable junction of multimaterials <br/> <br/>Author, co-author: Lecomte-Beckers, Jacqueline; Lecomte, Jacky; Gerlach, Nathalie; Collard, Vincent; Svarova, Petra; Wenkin, Mireille; Novello, Frederic <br/> <br/>Abstract: This collective project aimed to assess the potential of adhesive bonding in various applications in the field of building construction. This evaluation takes into account technical, economical and ecological aspects and provides a methodology that can be easily transferred to other applications. Fri, 19 Apr 2013 07:37:28 GMT http://hdl.handle.net/2268/146845 Title: Identification and validation of CRSS values for Ti6Al4V alloy <br/> <br/>Author, co-author: Habraken, Anne Mon, 15 Apr 2013 12:28:52 GMT http://hdl.handle.net/2268/146844 Title: A mixed solid-shell element for the analysis of laminated composites <br/> <br/>Author, co-author: Rah, Kamran; Paepegem, Wim; Habraken, Anne; Degrieck, Joris Mon, 15 Apr 2013 12:19:12 GMT http://hdl.handle.net/2268/146799 Title: Continuous synthesis of porous carbon xerogel beads. Communication présentée par D. Eskenazi <br/> <br/>Author, co-author: Eskenazi, David; Kreit, Patrick; Compère, Philippe; Pirard, Jean-Paul; Job, Nathalie Mon, 15 Apr 2013 07:19:40 GMT http://hdl.handle.net/2268/146797 Title: Continuous synthesis of porous carbon xerogel beads. <br/> <br/>Author, co-author: Eskenazi, David; Kreit, Patrick; Compère, Philippe; Pirard, Jean-Paul; Job, Nathalie Mon, 15 Apr 2013 07:15:28 GMT http://hdl.handle.net/2268/146545 Title: Towards fracture prediction in single point incremental forming <br/> <br/>Author, co-author: Guzmán Inostroza, Carlos Felipe; Habraken, Anne <br/> <br/>Abstract: The stress state in metal forming processes usually implies low values of triaxiality. It is well known that damage models based only on triaxiality fails to capture the damage behavior properly, and recent articles have stressed the effect of the Lode parameter in describing damage. Moreover, in some process like incremental forming, the through thickness shear could dominate the rupture mechanism making the description, using solely the triaxiality, inaccurate. In this paper, a preliminary study of the stress state is carried over a near-to-failure single point incremental forming (SPIF) formed cone, through finite elements simulations using a newly developed solid-shell element. The results provide a basis for further studies into damage development in SPIF. Wed, 10 Apr 2013 12:12:09 GMT http://hdl.handle.net/2268/146505 Title: Dépôt de nanoparticules par voie humide <br/> <br/>Author, co-author: Job, Nathalie Tue, 09 Apr 2013 15:47:25 GMT http://hdl.handle.net/2268/146502 Title: Comment diminuer la quantité de platine dans les piles à combustible ? <br/> <br/>Author, co-author: Laurent-Brocq, M.; Caldarella, Giuseppe; Job, Nathalie; Pireaux, J.-J. Tue, 09 Apr 2013 15:45:42 GMT http://hdl.handle.net/2268/146501 Title: Electrocatalyst by scientific method of Charge Enhanced Dry Impregnation. <br/> <br/>Author, co-author: Cao, Chongjiang; Lambert, Stéphanie; Pirard, Jean-Paul; Job, Nathalie Tue, 09 Apr 2013 15:43:57 GMT http://hdl.handle.net/2268/146500 Title: Physico-chemical and electrochemical properties of Pt/carbon xerogel catalysts prepared by the SEA method. Poster présenté par A. Zubiaur <br/> <br/>Author, co-author: Zubiaur, Anthony; Chatenet, M.; Maillard, F.; Lambert, Stéphanie; Pirard, Jean-Paul; Job, Nathalie Tue, 09 Apr 2013 15:42:48 GMT http://hdl.handle.net/2268/146499 Title: Propriétés physicochimiques et électrochimiques de catalyseurs Pt/xérogel de carbone synthétisés par la méthode de SEA multiple. <br/> <br/>Author, co-author: Zubiaur, Anthony; Chatenet, M.; Maillard, F.; Lambert, Stéphanie; Pirard, Jean-Paul; Job, Nathalie Tue, 09 Apr 2013 15:41:44 GMT http://hdl.handle.net/2268/146498 Title: Fonctionnalisation surfacique de poudre de carbone pour greffer des nanoparticules métalliques par plasma. <br/> <br/>Author, co-author: Laurent-Brocq, M.; Job, Nathalie; Pireaux, J.-J. Tue, 09 Apr 2013 15:38:53 GMT http://hdl.handle.net/2268/146497 Title: Xérogels de carbone à base de résorcinol-formaldehyde en tant que matériaux d'anode pour batterie Li-ion : influence de la porosité sur la capacité et le comportement lors des cycles d'insertion-désinsertion <br/> <br/>Author, co-author: Piedboeuf, Marie-Laure; Léonard, Alexandre; Khomenko, V.; Senyk, I.; Pirard, Jean-Paul; Job, Nathalie Tue, 09 Apr 2013 15:38:06 GMT