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See detailCohesive Band Model: a triaxiality-dependent cohesive model inside an implicit non-local damage to crack transition framework
Leclerc, Julien ULiege; Wu, Ling ULiege; Nguyen, Van Dung ULiege et al

Conference (2017, June 14)

Accurate numerical prediction of the whole ductile failure process is still a challenge. The adequate numerical scheme has to concord with the physical reality composed of an initial diffuse damage step ... [more ▼]

Accurate numerical prediction of the whole ductile failure process is still a challenge. The adequate numerical scheme has to concord with the physical reality composed of an initial diffuse damage step followed by ultimate localised crack initiation and propagation. Currently, two main modelling philosophies exist. On the one hand, continuous approaches, described by damage models, are suited for diffuse damage, but are unable to represent physical discontinuities. On the other hand, discontinuous approaches are suitable to describe crack propagation behaviour and other localised processes, but fail in diffuse damage prediction of ductile materials. Moreover, they do not usually capture triaxiality effects or in other words, in-plane stretch effects, which are mandatory for accurate ductile failure simulations. To describe the ductile failure process, the numerical scheme proposed here combines both approaches and by this way, their respective advantages: an implicit non-local damage model combined with an extrinsic cohesive law in a discontinuous Galerkin finite element framework [1]. An application example of this scheme is shown on the attached figure with a comparison of the experimental force-displacement curve [2]. An implicit non-local model [3] is involved to model the initial diffuse damage stage. Upon damage to crack transition, a cohesive band [4] is used as cohesive law in order to introduce in-plane stretch effects during the crack propagation. This model is based on the assumption that all the damaging process occurs inside a band of small but finite thickness ahead of the crack surface. The strains inside this band is obtained from the neighbouring strains and from the cohesive jump. Then, the stress-state inside the band and the cohesive traction forces on the crack lips are deduced from the underlying continuum damage model. The band thickness is not a new material parameter but it is computed to ensure the energetic consistency of the numerical scheme [5]. [1] Wu L, Becker G, Noels L. Elastic damage to crack transition in a coupled non-local implicit discontinuous Galerkin/extrinsic cohesive law framework. Comput. Methods Appl. Mech. Eng. 279 (2014): 379–409 [2] Geers M., de Borst R., Brekelmans W., Peerlings R. Validation and internal length scale determination for a gradient damage model: application to short glass-fibre-reinforced polypropylene. Int. J. of Sol. and Struct. 36 (1999): 2557‑2583. [3] Peerlings R., de Borst R., Brekelmans W., Ayyapureddi S. Gradient-enhanced damage for quasi-brittle materials, Int. J. for Num. Methods in Eng. 39 (1996): 3391-3403 [4] Remmers J. J. C., de Borst R., Verhoosel C. V., Needleman A. The cohesive band model: a cohesive surface formulation with stress triaxiality. Int. J. Fract. 181 (2013): 177–18 [5] Leclerc J., Wu L., Nguyen V.D., Noels L. Cohesive band model: a cohesive model with triaxiality for crack transition in a coupled non-local implicit discontinuous Galerkin/extrinsic cohesive law framework. Int. J. for Num. Methods in Eng. (2017): In preparation. [less ▲]

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See detailJavier Cercas, Le mobile
Licata, Nicolas ULiege

E-print/Working paper (2017)

Synopsis d'une nouvelle de Javier Cercas intitulée Le mobile (1987), rédigé dans le cadre du dossier "Les lectures pour l'été 2017" de la revue Culture.

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See detailCharacterization of meat retail conditions in Kigali city (Rwanda): hygienic practices and determinants for Salmonella occurrence
Niyonzima, Eugene ULiege; Hategekimana, Jean Paul; Minani, Félicien et al

Poster (2017, June 14)

Salmonella is one of the leading bacterial food borne pathogens worldwide and meat constitutes one of the major vehicles for human Salmonella infections. Salmonella illnesses represent an important public ... [more ▼]

Salmonella is one of the leading bacterial food borne pathogens worldwide and meat constitutes one of the major vehicles for human Salmonella infections. Salmonella illnesses represent an important public health concern particularly in countries with growing economies such as Rwanda. The objective of this study was to characterize the retail conditions and to determine the microbiological quality and safety of meat retailed within the establishments of Kigali city. A survey was carried out in 150 establishments of Kigali city to characterize the meat retail conditions through a structured questionnaire, whereas 270 meat samples were analyzed for the enumeration of hygiene indicator bacteria and the qualitative detection of Salmonella by using conventional culture methods. Furthermore, the risk factors associated to the occurrence of Salmonella in the commercialized meat pieces were identified trough a binary logistic regression analysis. The first results from this study indicate that beef is the type of meat sold the most within retail premises of Kigali city and meat from animal species other than bovines are generally commercialized in large establishments. The levels of hygiene indicator bacteria were found to be relatively high and Salmonella was detected in 19.6% of all retailed meat samples. Factors such as the exposition of retailed meat at ambient temperature, the utilization of wooden cutting boards with rough surfaces which are difficult to sanitize as well as the lack of trained personnel in hygienic meat handling practices; were found to be significantly associated to the risk of Salmonella occurrence in the retailed meat. The findings from this study highlight the need for improvements in hygienic meat handling practices particularly in small and medium meat retail establishments in Kigali city [less ▲]

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See detailLegal presumptions of fault in the wake of the transposition of Directive 2014/104/EU
Van Cleynenbreugel, Pieter ULiege

Conference (2017, June 14)

This paper looks at the role played by legal presumptions in the transposition of the directive on damages and whether this differs from the use of legal presumptions in other contexts of EU competition ... [more ▼]

This paper looks at the role played by legal presumptions in the transposition of the directive on damages and whether this differs from the use of legal presumptions in other contexts of EU competition law enforcement. [less ▲]

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See detailBody shape convergence driven by small size optimum in marine angelfishes
Frederich, Bruno ULiege; Santini, Francesco; Konow, Nicolai et al

in Biology Letters (2017), 13

Convergent evolution of small body size occurs across many vertebrate clades and may reflect an evolutionary response to shared selective press- ures. However it remains unclear if other aspects of ... [more ▼]

Convergent evolution of small body size occurs across many vertebrate clades and may reflect an evolutionary response to shared selective press- ures. However it remains unclear if other aspects of phenotype undergo convergent evolution in miniaturized lineages. Here we present a comparative analysis of body size and shape evolution in marine angelfishes (Pomacanthidae), a reef fish family characterized by repeated transitions to small body size. We ask if lineages that evolve small sizes show convergent evolution in body shape. Our results reveal that angelfish lineages evolved three different stable size optima with one corresponding to the group of pygmy angelfishes (Centropyge). Then, we test if the observed shifts in body size are associated with changes to new adaptive peaks in shape. Our data suggest that independent evolution to small size optima have induced repeated convergence upon deeper body and steeper head profile in Centropyge. These traits may favour manoeuvrability and visual aware- ness in these cryptic species living among corals, illustrating that functional demands on small size may be related to habitat specialization and predator avoidance. The absence of shape convergence in large marine angelfishes also suggests that more severe requirements exist for small than for large size optima. [less ▲]

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See detailAnalyse qualitative et méthodes (a)preceptives
Englebert, Jérôme ULiege

Scientific conference (2017, June 13)

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See detailTips and tricks to make your HRS4R implementation a success
Halleux, Isabelle ULiege

Scientific conference (2017, June 13)

This presentation aims to share the experience of the University of Liege that was awared the "HR excellence in research" logo by the EU in 2011. This lead the institution to develop an action plan for ... [more ▼]

This presentation aims to share the experience of the University of Liege that was awared the "HR excellence in research" logo by the EU in 2011. This lead the institution to develop an action plan for enhancing the working conditions of the researchers, to open positions to foreign researchers and to offer them training as services for their career development. [less ▲]

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See detailModulation strategies of integrated HVAC systems used in residential buildings for demand-side management at different scales
Georges, Emeline ULiege

Doctoral thesis (2017)

The integration of renewable energy sources in the electricity production mix has an important impact on the management of the electricity grid, due to their intermittency. In particular, to ensure grid ... [more ▼]

The integration of renewable energy sources in the electricity production mix has an important impact on the management of the electricity grid, due to their intermittency. In particular, to ensure grid balancing, there is a rising need for flexibility, both on the supply and demand sides. A possible solution to help achieve grid balancing is the smart modulation of the electrical load in a "demand following supply" scheme through demand-side management. In this context, the objective of this doctoral thesis is to assess the amount of flexibility that can be harvested from the management of residential thermostatically-controlled loads and, in particular, through the use of heat pumps and storage. To that end, a modeling and control framework is developed to define efficient and scalable optimal load modulation strategies. The flexibility potential is investigated in different contexts: day-ahead electricity market, matching of decentralized electricity production and provision of ancillary services. Different scales are considered, from a single building to several thousand buildings. [less ▲]

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See detailAlle origini della conservazione in Belgio: il contributo originale di Louis Van der Swaelmen
Rapalo, Maria Chiara ULiege

Doctoral thesis (2017)

La recherche proposée s’intègre dans le cadre d'une collaboration entre l'Italie et la Belgique portant sur les questions de la conservation et de la protection du paysage, lies au thème de l'urbanisme ... [more ▼]

La recherche proposée s’intègre dans le cadre d'une collaboration entre l'Italie et la Belgique portant sur les questions de la conservation et de la protection du paysage, lies au thème de l'urbanisme. L’objectif de cette collaboration est de mettre en évidence les contributions d’échelles diverses qui, dans le contexte belge, ont contribué à l'émergence des directives internationales actuelles dans le domaine de la conservation et de la protection des centres historiques et du paysage. Ces dernières années, le concept de paysage a fait l’objet d’une attention croissante de la part d'universitaires et d'experts appartenant à différentes disciplines. Au cours du XXe siècle, ce concept a connu une importante évolution au contact de ces disciplines ; en résulte ce que l’on nomme aujourd’hui le paysage urbain historique, qui est « le résultat d’une stratification historique de valeurs et caractères culturels et naturels qui vont au-delà de la notion de centre historique ou ensemble, jusqu'à inclure le contexte urbain le plus large et son emplacement (setting) géographique » (ajouter référence). Prenant en compte les perceptions et relations visuelles, les pratiques et valeurs sociales et culturelles, les processus économiques et les dimensions immatérielles du patrimoine liés à la diversité et l'identité des différentes cultures locales, l'approche du paysage urbain historique soutient les communautés dans leur quête de développement et d'adaptation, tout en conservant les caractéristiques et les valeurs liées à leur histoire, leur mémoire collective et leur environnement. Dès l’entre-deux-guerres, plusieurs personnalités ont abordé le problème des sites à partir de domaines jusque là distincts au profit d’une vision globale, liant les instances historique et esthétique de la ville et donc, la protection et la restauration du patrimoine et celle du paysage. Avec d’autres personnalités remarquables, tel Charles Buls, l’architecte-paysagiste Louis Van der Swaelmen a joué, dans le contexte belge, un rôle essentiel dans cette évolution de la culture de la conservation de la seule prise en compte des monuments à celle de la dimension urbaine. Avant tout connu comme planificateur et architecte-paysagiste urbain dans le cadre du Mouvement Moderne – dont il a été l'un des promoteurs –, Louis Van der Swaelmen est l’auteur des premières cités-jardins belges dans le premier tiers du XXe siècle. A ce jour, il est considéré comme l'un des acteurs principaux de la reconstruction d'une Belgique en grande partie détruite par l'artillerie allemande. En effet, après une période d'exil aux Pays-Bas lors de la Première Guerre mondiale, il rassemble une abondante documentation qui servira de base théorique non seulement aux travaux de reconstruction, mais aussi au développement du nouveau. En revanche, il est peu connu pour sa mobilisation en faveur de la protection et de la conservation des sites. Pourtant, on peut affirmer que Louis Van der Swaelmen fait partie des architectes qui ont conduit au changement de l'image du paysage belge, à un moment significatif de l'histoire architecturale nationale et européenne. L'objectif de cette étude a été non seulement d'examiner la figure de Louis Van Der Swaelmen en tant qu’architecte-paysagiste, personnalité émergente dans le contexte du développement urbain et précurseur du Mouvement Moderne belge, mais surtout de restituer sa culture architecturale et sa pensée dans le contexte national et international de la conservation, avec l’émergence de l’intérêt pour les sites et paysages. L’oeuvre de Van de Swaelmen se développe à une période particulière de l'histoire de la Belgique, où la construction d’une identité, notamment à travers la formation d’un esprit artistique national, est essentielle. Sur la scène internationale, les bases d'une conservation des sites, étroitement liés à l'évolution de la société dans son ensemble, ont été posées. Les contributions théoriques liées à la période complexe de la seconde moitié du XIXe siècle jusqu'aux années 1930 ont été essentielles, avec la conférence d'Athènes de 1931 et le Congrès du CIAM de 1933. Parmi celles-ci émergent les réflexions de Victor Hugo en France, de Goethe en Allemagne, de John Ruskin et du mouvement Arts and Crafts de William Morris en Grande-Bretagne, les études sur la culture historique de l'espace urbain de Camillo Sitte, la théorie du Kunstwollen de Alois Riegl ou encore les progrès dans le domaine de l'esthétique allemande de Gottfried Semper et les théories de Friedrich Theodor Vischer. Toutes ces expériences ont contribué, d'une façon plus ou moins visible, à l'évolution des mécanismes d’élaboration des directives internationales dans le domaine de la conservation et de la protection des centres historiques et du paysage. On peut donc considérer que Louis Van der Swaelmen a été formé dans un contexte très stimulant, non seulement par les contributions européennes dans le domaine de la conservation, mais aussi par les influences importantes anglaises, françaises, allemandes et néerlandaises qui ont marqué, après la Première Guerre mondiale, le monde de la planification urbaine et de la conservation dans le contexte belge. L’étude a été également l’occasion de comprendre et définir les points de contact entre les théories de conservation et celles de l'urbanisme, qui aujourd'hui, selon une vision simpliste de la réalité, sont considérées dans certains cas comme éloignées voire opposées. L'un des objectifs a été, par conséquent, contribuer à l'idée qu'au contraire, l’acte de la conservation et le projet du nouveau (soit en milieu urbain ou non), ne sont que des moments différents et complémentaires du même acte culturel. [less ▲]

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See detailMacro-Kinematic Approach for Shear Behaviour of Short Coupling Beams with Conventional Reinforcement
Mihaylov, Boyan ULiege; Franssen, Renaud ULiege

Conference (2017, June 13)

Short coupling beams in wall structures work predominantly in shear and develop complex deformation patterns. For this reason they cannot be modelled based on the classical plane-sections-remain-plane ... [more ▼]

Short coupling beams in wall structures work predominantly in shear and develop complex deformation patterns. For this reason they cannot be modelled based on the classical plane-sections-remain-plane hypothesis, and are typically designed with strut-and-tie models. However, because strut-and-tie models are inherently conservative, they can result in very large amounts of shear reinforcement (stirrups), and therefore significant construction difficulties. In addition, strut-and-tie models do not provide information about the deformation capacity of coupling beams, which is important for performance-based seismic design. To address these challenges, this paper discusses a three-parameter kinematic theory (3PKT) for the shear strength and deformation patterns of short coupling beams. The 3PKT approach is situated between simple and conservative strut-and-tie models and complex non-linear finite element (FE) models. While FE models use a large number of degrees of freedom (DOFs) to describe the deformation patterns in coupling beams, the 3PKT method is based on a kinematic model with only three DOFs. The paper presents the formulation of the model and its validation with tests. [less ▲]

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See detailStudy of the regulation of β-lactam resistance in Enterococcus hirae
Raymackers, Alice ULiege; Maréchal, Maxime; Verlaine, Olivier ULiege et al

Poster (2017, June 13)

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See detailGFR and drug dosage adaptation: are we still in the mist?
DELANAYE, Pierre ULiege

Conference (2017, June 13)

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See detailAcute renal failure: definition and detection
DELANAYE, Pierre ULiege

Conference (2017, June 13)

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See detailHome Sweet Home : Quatre fenêtres ouvertes sur le logement
Dethier, Perrine ULiege; Quintart, Aurélie ULiege; Uyttebrouck, Constance ULiege et al

Conference given outside the academic context (2017)

Malgré des parcours de vie très variés, nous sommes tous confrontés à la nécessité de nous loger. La majorité des ménages belges fait le choix d’acheter un logement plutôt que de le louer. Quatre ... [more ▼]

Malgré des parcours de vie très variés, nous sommes tous confrontés à la nécessité de nous loger. La majorité des ménages belges fait le choix d’acheter un logement plutôt que de le louer. Quatre doctorants feront le point sur quatre étapes clés du parcours du citoyen pour un logement. [less ▲]

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See detailLa révolution du roman-feuilleton
Durand, Pascal ULiege

Conference (2017, June 13)

Detailed reference viewed: 37 (3 ULiège)
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See detailResting state connectivity between default mode network and insula encodes acute migraine headache
Coppola, Gianluca; Di Renzo, Antonio; Tinelli, Emanuele et al

in Cephalalgia : An International Journal of Headache (2017), 0(0), 1-9

Background: Previous functional MRI studies have revealed that ongoing clinical pain in different chronic pain syndromes is directly correlated to the connectivity strength of the resting default mode ... [more ▼]

Background: Previous functional MRI studies have revealed that ongoing clinical pain in different chronic pain syndromes is directly correlated to the connectivity strength of the resting default mode network (DMN) with the insula. Here, we investigated seed-based resting state DMN-insula connectivity during acute migraine headaches. Methods: Thirteen migraine without aura patients (MI) underwent 3 T MRI scans during the initial six hours of a spontaneous migraine attack, and were compared to a group of 19 healthy volunteers (HV). We evaluated headache intensity with a visual analogue scale and collected seed-based MRI resting state data in the four core regions of the DMN: Medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC), and left and right inferior parietal lobules (IPLs), as well as in bilateral insula. Results: Compared to HV, MI patients showed stronger functional connectivity between MPFC and PCC, and between MPFC and bilateral insula. During migraine attacks, the strength of MPFC-to-insula connectivity was negatively correlated with pain intensity. Conclusion:We show that greater subjective intensity of pain during a migraine attack is associated with proportionally weaker DMN-insula connectivity. This is at variance with other chronic extra-cephalic pain disorders where the opposite was found, and may thus be a hallmark of acute migraine head pain. [less ▲]

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See detailLe Tarier pâtre pour comparer des habitats. Quelle qualité pour les plantations de sapins de Noël.
Gailly, Robin ULiege

Conference given outside the academic context (2017)

Detailed reference viewed: 30 (2 ULiège)