http://hdl.handle.net/2268/80 Chercher dans ce canal chercher http://orbi.ulg.ac.be/simple-search http://hdl.handle.net/2268/149120 Titre: Stratégies d'échantillonnage pour l'apprentissage par renforcement batch <br/> <br/>Auteur, co-auteur: Fonteneau, Raphaël; Murphy, Susan A.; Wehenkel, Louis; Ernst, Damien http://hdl.handle.net/2268/149089 Titre: Macroporous poly(ionic liquid)s and poly(acrylamide)s monoliths from CO2-in-water emulsion templates stabilized by sugar-based surfactants <br/> <br/>Auteur, co-auteur: Boyère, Cédric; Favrelle, Audrey; Léonard, Alexandre; Boury, Frank; Jérôme, Christine; Debuigne, Antoine <br/> <br/>Résumé: Highly interconnected poly(acrylamide) (PAM) and poly(vinylimidazolium) (PVIm) porous monoliths were templated by carbon 10 dioxide-in-water (CO2/W) high internal phase emulsions (HIPEs), a toxic-solvent free process. A range of sugar-based fluorinated surfactants prepared by chemoenzymatic synthesis were used as emulsifiers. Both the concentration and the structure of the surfactants, especially the length of their CO2-philic part and of their spacer between the sugar head and the tail, were found to strongly affect the cellular structure and morphology of the PAM polyHIPEs, i.e. the size of pores and cells. A mannose derivative bearing a chain ranging from 6 to 10 perfluorinated carbons and a long spacer emerged as the best stabilizer, leading to a porous monolith with average pores and 15 cells sizes (about 2.6 1m and 5-10 1m, respectively) among the lowest reported for polyHIPEs produced from CO2/W emulsions. The same template then served for the preparation of the first macroporous poly(ionic liquid)s (PILs) polyHIPE by using 1-vinyl-3- ethylimidazolium bromide as monomer. Shrinkage of the final material was prevented by adjusting the divinylimidazolium crosslinker content. The resulting low density polyHIPE exhibits small spherical cells (~5 1m) connected by numerous small pores (~2 1m), confirming that the CO2/W HIPE templating methodology based on fluorinated glycosurfactants is a technique of choice for the 20 preparation of macroporous PILs. http://hdl.handle.net/2268/149087 Titre: Comparison of three NDT techniques for the inspection of aeronautic composite structures <br/> <br/>Auteur, co-auteur: Dubé, Robin; Scheed, Laurent; Lewandoswki, Jacques; Mouret, Laurence; Georges, Marc http://hdl.handle.net/2268/149082 Titre: Effect of head-to-head addition in vinyl acetate controlled radical polymerization: why is Co(acac)2-mediated polymerization so much better? <br/> <br/>Auteur, co-auteur: Morin, Aurélie N.; Detrembleur, Christophe; Jérôme, Christine; De Tullio, Pascal; Poli, Rinaldo; Debuigne, Antoine <br/> <br/>Résumé: The controlled polymerization of vinyl acetate has been recently achieved by several techniques, but PVAc with targeted Mn and low dispersity up to very high monomer conversions and high degrees of polymerization was only obtained with Co(acac)2 as controlling agent in the so-called CMRP, a type of organometallic mediated radical polymerization (OMRP). Other techniques (including ATRP, ITP, TERP, and RAFT/MADIX) have shown a more or less pronounced slowdown in the polymerization kinetics, which was attributed to the higher strength of the C−X bond between the radical PVAc chain and the trapping agent (X) in the dormant species and to a consequent slower reactivation after a less frequent head-to-head monomer addition. The reason for the CMRP exception is clarified by the present contribution. First, a detailed investigation by 1H, 13C and multiplicity-edited HSQC and DEPT-135 NMR of the PVAc obtained by CMRP, in comparison with a regular polymer made by free radical polymerization under the same conditions, has revealed that Co(acac)2 does not significantly alter the fraction of head-to-head sequences in the polymer backbone and that there is no accumulation of Co(acac)2-capped chains with a head-to-head ω end. Hence, both dormant chains (following the head-to-head and the head-to-tail monomer additions) must be reactivated at similar rates. A DFT study shows that this is possible because the dormant chains are stabilized not only by the C−Co σ bond but also by formation of a chelate ring through coordination of the ω monomer carbonyl group. The head-to-head dormant chain contains an inherently stronger C−Co bond but forms a weaker 6-membered chelate ring, whereas the weaker C−Co bond in the head-to-tail dormant chain is compensated by a stronger 5-membered chelate ring. Combination of the two effects leads to similar activation enthalpies, as verified by DFT calculations using a variety of local, gradient-corrected, hybrid and “ad hoc” functionals (BPW91, B3PW91, BPW91*, M06 and M06L). While the BDE(C−X) of model H-VAc−X molecules [X = Cl, I, MeTe, EtOC(S)S and Co(acac)2] are functional dependent, the BDE difference between head-to-head and head-to-tail dormant chain models is almost functional insensitive, with values of 5−9 kcal/mol for the ATRP, ITP and TERP models, 3−6 for the RAFT/MADIX model, and around zero for CMRP. http://hdl.handle.net/2268/149003 Titre: Modélisation du captage post-combustion du CO2 avec évaluation de la dégradation des solvants; Modélisation du captage post-combustion du CO2 avec évaluation de la dégradation des solvants <br/> <br/>Auteur, co-auteur: Léonard, Grégoire; Léonard, Grégoire; BELLETANTE, Ségolène; BELLETANTE, Ségolène; Cabeza Mogador, Bruno; Cabeza Mogador, Bruno; Toye, Dominique; Toye, Dominique; Heyen, Georges; Heyen, Georges <br/> <br/>Résumé: Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy demand. CO2 is chemically absorbed in an amine solvent that can be regenerated at higher temperature, producing a pure CO2 stream. However, the large impact of this technology on the power plant efficiency and the environmental penalty are the main drawbacks for large-scale implementation. In this work, an innovative approach combining process modeling and evaluation of the environmental penalty due to amine degradation is presented. Based on experimental results, the kinetics of solvent oxidative and thermal degradation is estimated and included in the process model developed in Aspen Plus. Using this model, the influence of operating parameters like the oxygen concentration in the flue gas or the solvent regeneration pressure is studied. This model is a first step for a multi-objective optimization of the CO2 capture process, assessing both energy and environmental penalties of this technology.; Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy demand. CO2 is chemically absorbed in an amine solvent that can be regenerated at higher temperature, producing a pure CO2 stream. However, the large impact of this technology on the power plant efficiency and the environmental penalty are the main drawbacks for large-scale implementation. In this work, an innovative approach combining process modeling and evaluation of the environmental penalty due to amine degradation is presented. Based on experimental results, the kinetics of solvent oxidative and thermal degradation is estimated and included in the process model developed in Aspen Plus. Using this model, the influence of operating parameters like the oxygen concentration in the flue gas or the solvent regeneration pressure is studied. This model is a first step for a multi-objective optimization of the CO2 capture process, assessing both energy and environmental penalties of this technology.; Le captage post-combustion du CO2 en centrale électrique est une des technologies les plus matures pour réduire rapidement et à grande échelle les émissions de CO2 tout en répondant à la croissance de la demande mondiale en énergie. Le CO2 est absorbé chimiquement dans un solvant aminé qui est régénéré à haute température, produisant un flux de CO2 pur. Cependant, l’impact de cette technique sur le rendement énergétique de la centrale ainsi que l’impact environnemental lié à la dégradation du solvant aminé freinent l’implémentation à grande échelle. Dans ce travail, une approche innovante combinant l’étude des impacts énergétiques et environnementaux est présentée. Sur base de résultats expérimentaux considérant à la fois la dégradation oxydative et la dégradation thermique sous CO2, la cinétique de dégradation des solvants est évaluée et insérée dans un modèle du procédé réalisé dans le logiciel Aspen Plus. Ce modèle permet d’étudier l’influence des conditions opératoires du procédé telles que la teneur en oxygène des fumées ou la pression de régénération. Il constitue une première étape pour une optimisation multi-objectif du procédé de captage de CO2 afin d’identifier un compromis entre le coût énergétique de cette technologie et son impact environnemental.; Le captage post-combustion du CO2 en centrale électrique est une des technologies les plus matures pour réduire rapidement et à grande échelle les émissions de CO2 tout en répondant à la croissance de la demande mondiale en énergie. Le CO2 est absorbé chimiquement dans un solvant aminé qui est régénéré à haute température, produisant un flux de CO2 pur. Cependant, l’impact de cette technique sur le rendement énergétique de la centrale ainsi que l’impact environnemental lié à la dégradation du solvant aminé freinent l’implémentation à grande échelle. Dans ce travail, une approche innovante combinant l’étude des impacts énergétiques et environnementaux est présentée. Sur base de résultats expérimentaux considérant à la fois la dégradation oxydative et la dégradation thermique sous CO2, la cinétique de dégradation des solvants est évaluée et insérée dans un modèle du procédé réalisé dans le logiciel Aspen Plus. Ce modèle permet d’étudier l’influence des conditions opératoires du procédé telles que la teneur en oxygène des fumées ou la pression de régénération. Il constitue une première étape pour une optimisation multi-objectif du procédé de captage de CO2 afin d’identifier un compromis entre le coût énergétique de cette technologie et son impact environnemental. http://hdl.handle.net/2268/148961 Titre: Design, implementation, and preliminary tests of the emergency beacon transmitter of the OUFTI-1 nanosatellite of the University of Liège, as of March 2013 <br/> <br/>Auteur, co-auteur: Crosset, Nicolas; Werner, Xavier; Denis, Amandine; Broun, Valéry; Pisane, Jonathan; Verly, Jacques http://hdl.handle.net/2268/148960 Titre: Automatic target recognition with passive bistatic radars, with applications to the detection of anomalies in the civilian air traffic <br/> <br/>Auteur, co-auteur: Pisane, Jonathan; Azarian, Sylvain; Lesturgie, Marc; Verly, Jacques http://hdl.handle.net/2268/148958 Titre: Prévision des rendements agricoles. Guide d'utilisation. <br/> <br/>Auteur, co-auteur: Bronne, Charles-Emmanuel; Wellens, Joost; Midekor, Akoly Agblévi; Diakité, Mamadou; Denis, Antoine; Tychon, Bernard <br/> <br/>Résumé: Manuel présentant une méthode, développée par l'Université de Liège, de prévision de la production agricole. Cette méthode se base sur l'utilisation de différents programmes informatiques, et a pour but de prévoir le rendement agricole à partir de données météorologiques, agrométéorologiques, et NDVI (télédétecté). Elle est appliquée dans ce manuel sur les cultures du coton et du maïs au Burki Faso. http://hdl.handle.net/2268/148939 Titre: A surface engineering approach applicable to concrete repair engineering <br/> <br/>Auteur, co-auteur: Garbacz, Andrzej; Courard, Luc; Bissonnette, Benoît <br/> <br/>Résumé: The objective of the paper is to analyze the effect of surface roughness and superficial microcracking upon dhesion of repair systems using concrete surface engineering approach. The results presented in this paper have been obtained within the framework of research projetcs performed to develop a better understanding of factors affecting the adhesion of repair materials through a surface engineering approach. Based on the results of investigations, the authors showed that the durability and quality of concrete repairs depend to a large degree on the characteristics of the substrate. Mechanical preparation and profiling of the concrete surface to be repaired has to be balanced with potential co-lateral effects such as superficial cracking, too often induced as a result of inappropriate concrete removal method selection, and the loss of benefits due to better mechanical anchorage. The results obtained confirm also that Concrete Surface Engineering, as a scientific concept, will definitely contribute to shed more light on how to optimize repair bond, taking into account interactions between materials at different observation scales. http://hdl.handle.net/2268/148846 Titre: Les projets SUN et SOLEN : Soutenir la régénération durable des quartiers. <br/> <br/>Auteur, co-auteur: Ruelle, Christine; Marique, Anne-Françoise; Reiter, Sigrid; Teller, Jacques http://hdl.handle.net/2268/148832 Titre: Workshops as tools for creative collaboration: finding a balance between facilitation and auto-organization <br/> <br/>Auteur, co-auteur: Elsen, Catherine; Cornet, Adeline; Antoine, Mélanie <br/> <br/>Résumé: This paper analyses four settings of so-called collaborative “creative workshops” (their methods, logistics, regulation processes) and provide peepholes on their respective features, with the informed goals of defining criteria for comparison, finding shared essence and distinctive characteristics. Key aspects such as time, facilitation and auto-organization shape a “creative continuum” that formalizes how creativity can be stimulated and how participants might collaboratively develop creative behaviors. http://hdl.handle.net/2268/148825 Titre: Solar buildings and the urban environment <br/> <br/>Auteur, co-auteur: Marique, Anne-Françoise; Reiter, Sigrid http://hdl.handle.net/2268/148824 Titre: L'outil SAFE : un outil interactif d’évaluation des consommations énergétiques des bâtiments résidentiels et des déplacements des personnes <br/> <br/>Auteur, co-auteur: Marique, Anne-Françoise; Reiter, Sigrid http://hdl.handle.net/2268/148822 Titre: Models and prospects for a sustainable suburban transition. <br/> <br/>Auteur, co-auteur: Marique, Anne-Françoise; Reiter, Sigrid <br/> <br/>Résumé: This paper addresses the challenges, transformations and conditions of a sustainable suburban transition. Two powerful levers are used: (1) urban form, which is considered in addition to the individual building scale, and (2) mobility, because sprawl spatially separates activities, resulting in an increase in travel distances and energy used in transportation. Two main indicators (the heating needs of different types of suburban forms and a commute performance index) are developed and discussed. Three scenarios focused on the evolution of the existing building stock are modelled and assessed (the retrofitting of existing neighbourhoods, an increase in the built density and demolition / reconstruction) to answer two main questions: "how to intervene in suburban areas?" and" where to intervene? ". These main results focused on energy efficiency are then studied in a larger framework to highlight the opportunities, limitations, constraints and feasibility of each strategy. Concrete prospects and guidelines for policy makers are finally proposed to operationalize a "sustainable suburban renewal". These findings show that, beyond the traditional polarization of the debates on energy efficiency of our built environment between the “compact city” and the “sprawled city”, a new pragmatic paradigm, focused on the transition of suburban areas by densification, can make suburban areas evolve towards more sustainability. http://hdl.handle.net/2268/148821 Titre: Perspectives pour une transition durable des territoires périurbains. <br/> <br/>Auteur, co-auteur: Marique, Anne-Françoise; Reiter, Sigrid <br/> <br/>Résumé: L’article traite de la transition durable des territoires périurbains. Deux leviers d’action sont mobilisés à cette fin: (1) la forme urbaine et (2) la mobilité. Trois types de scénarios centrés sur une évolution du stock bâti existant sont modélisés et évalués (la rénovation énergétique, la densification et la démolition/reconstruction) de façon à répondre à deux questions : « comment intervenir dans les quartiers périurbains existants? » et « où intervenir? ». Ces simulations montrent que le renouvellement périurbain par densification des quartiers les mieux localisés permet de dépasser le clivage traditionnel entre les modèles de la « ville compacte » et de la « ville diffuse », en offrant de véritables opportunités pour la transition durable des territoires périurbains existants. Ces résultats théoriques, et appréhendés du seul point de vue énergétique, sont ensuite recadrés dans un contexte plus large pour mettre en évidence les opportunités, les limitations, les contraintes et la faisabilité de ces scénarios. http://hdl.handle.net/2268/148820 Titre: Des quartiers durables en Wallonie. Etat d'avancement des travaux relatifs à l'évaluation des projets de quartiers durables. <br/> <br/>Auteur, co-auteur: Teller, Jacques; Marique, Anne-Françoise http://hdl.handle.net/2268/148782 Titre: Computational Homogenization for Laminated Ferromagnetic Cores in Magnetodynamics <br/> <br/>Auteur, co-auteur: Niyonzima, Innocent; V Sabariego, Ruth; Dular, Patrick; Henrotte, François; Geuzaine, Christophe <br/> <br/>Résumé: In this paper, we investigate the modeling of ferromagnetic multiscale materials. We propose a computational homogenization technique based on the heterogeneous multiscale method (HMM) that includes both eddy-current and hysteretic losses at the mesoscale. The HMM comprises: 1) a macroscale problem that captures the slow variations of the overall solution; 2) many mesoscale problems that allow to determine the constitutive law at the macroscale. As application example, a laminated iron core is considered. http://hdl.handle.net/2268/148766 Titre: Lyapunov-based sufficient conditions for exponential stability in hybrid systems <br/> <br/>Auteur, co-auteur: Teel, Andrew; Forni, Fulvio; Zaccarian, Luca <br/> <br/>Résumé: Lyapunov-based sufficient conditions for exponential stability in hybrid systems are presented. The focus is on converting non-strict Lyapunov conditions, having certain observability properties, into strict Lyapunov conditions for exponential stability. Both local and global results are considered. The utility of the results is illustrated through an example. http://hdl.handle.net/2268/148763 Titre: Follow the bouncing ball: global results on tracking and state estimation with impacts <br/> <br/>Auteur, co-auteur: Forni, Fulvio; Teel, Andrew; Zaccarian, Luca <br/> <br/>Résumé: In this paper we formulate tracking and state- estimation problems of a translating mass in a polyhedral billiard as a stabilization problem for a suitable set. Due to the discontinuous trajectories arising from the impacts, we use hybrid systems stability analysis tools to establish the results. Using a novel concept of mirrored images of the target mass we prove that 1) a tracking control algorithm, and 2) an observer algorithm guarantee global exponential stability results for specific classes of polyhedral billiards, including rectangles. Moreover, we combine these two algorithms within dynamic controllers that guarantee global output feedback tracking. The results are illustrated via simulations. http://hdl.handle.net/2268/148711 Titre: Transboundary hydraulic modelling of extreme floods in the Meuse River <br/> <br/>Auteur, co-auteur: Dewals, Benjamin; Erpicum, Sébastien; Pirotton, Michel; Archambeau, Pierre <br/> <br/>Résumé: Detailed inundation modelling was conducted along a 100 km long transnational section of the Meuse River (in Belgium and The Netherlands), using very similar models for the whole computation (2D unsteady models). As a result, damping of the flood waves could be quantified and the possible relevance of using a steady-state approach could be assessed. The new detailed 2D hydraulic simulations have demonstrated that only a very limited damping of the flood waves occurs along the simulated reaches. From the perspective of the variation in peak discharge, the study concludes that running the hydraulic model in steady mode makes perfectly sense. Nonetheless, the steady computations lead to extensive overestimations of the inundated extent and of the stored volume in the floodplains. The 2D unsteady model constitutes also a tool of primary interest, which is readily available to design and evaluate protection measures for flood-prone areas such as in the city of Liege.