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See detailTwo-domain and three-domain limit cycles in a typical aeroelastic system with freeplay in pitch
Verstraelen, Edouard ULg; Dimitriadis, Grigorios ULg; Dal Ben Rossetto, Gustavo et al

in Journal of Fluids & Structures (2017), 69

Freeplay is a significant source of nonlinearity in aeroelastic systems and is strictly regulated by airworthiness authorities. It splits the phase plane of such systems into three piecewise linear ... [more ▼]

Freeplay is a significant source of nonlinearity in aeroelastic systems and is strictly regulated by airworthiness authorities. It splits the phase plane of such systems into three piecewise linear subdomains. Depending on the location of the freeplay, limit cycle oscillations can result that span either two or three of these subdomains. The purpose of this work is to demonstrate the existence of two-domain cycles both theoretically and experimentally. A simple aeroelastic system with pitch, plunge and control deflection degrees of freedom is investigated in the presence of freeplay in pitch. It is shown that two-domain and three-domain cycles can result from a grazing bifurcation and propagate in the decreasing airspeed direction. Close to the bifurcation, the two limit cycle branches interact with each other and aperiodic oscillations ensue. Equivalent linearization is used to derive the conditions of existence of each type of limit cycle and to predict their amplitudes and frequencies. Comparisons with measurements from wind tunnel experiments demonstrate that the theory describes these phenomena with accuracy. [less ▲]

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See detailMeasurement of pleural pressure swings with a fluid-filled esophageal catheter vs pulmonary artery occlusion pressure
VERSCHEURE, Sara ULg; MASSION, Paul ULg; GOTTFRIED, S et al

in Journal of Critical Care (2017), 37

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See detailThe EU financial transaction tax project
Van Cleynenbreugel, Pieter ULg; Devroe, Wouter

in De Witte, Bruno; Vos, Ellen; Ott, Andrea (Eds.) Between Flexibility and Disintegration The Trajectory of Differentiation in EU Law (2017)

This chapter analyses to what extent the EU's proposals to establish a financial transaction tax promote a fast track Europe in domains related to the core of the EU's internal market competences. It also ... [more ▼]

This chapter analyses to what extent the EU's proposals to establish a financial transaction tax promote a fast track Europe in domains related to the core of the EU's internal market competences. It also analyses the potential risks and negative consequences such an approach may trigger. [less ▲]

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See detailPrix fixe du livre : les propositions belges contredisent-elles le droit européen de la concurrence ?
Van Cleynenbreugel, Pieter ULg

in Tijdschrift voor Belgische Mededinging [=TBM] = Revue de la Concurrence Belge [=RCB] (2017), 4

Cet article analyse la compatibilité des propositions par les gouvernements communautaires belges des décrets relatifs aux prix fixes du livre, d'un point de vue du droit du marché intérieur ainsi que du ... [more ▼]

Cet article analyse la compatibilité des propositions par les gouvernements communautaires belges des décrets relatifs aux prix fixes du livre, d'un point de vue du droit du marché intérieur ainsi que du droit européen de la concurrence. [less ▲]

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See detailThe recent increase of atmospheric methane from 10 years of ground-based NDACC FTIR observations since 2005
Bader, Whitney ULg; Bovy, Benoît ULg; Conway, Stephanie et al

in Atmospheric Chemistry and Physics (2017)

Changes of atmospheric methane total columns (CH4/ since 2005 have been evaluated using Fourier transform infrared (FTIR) solar observations carried out at 10 ground-based sites, affiliated to the Network ... [more ▼]

Changes of atmospheric methane total columns (CH4/ since 2005 have been evaluated using Fourier transform infrared (FTIR) solar observations carried out at 10 ground-based sites, affiliated to the Network for Detection of Atmospheric Composition Change (NDACC). From this, we find an increase of atmospheric methane total columns of 0.31±0.03 %/year (2-sigma level of uncertainty) for the 2005–2014 period. Comparisons with in situ methane measurements at both local and global scales show good 10 agreement. We used the GEOS-Chem chemical transport model tagged simulation, which accounts for the contribution of each emission source and one sink in the total methane, simulated over 2005–2012. After regridding according to NDACC vertical layering using a conservative 15 regridding scheme and smoothing by convolving with respective FTIR seasonal averaging kernels, the GEOS-Chem simulation shows an increase of atmospheric methane total columns of 0.35±0.03 %/year between 2005 and 2012, which is in agreement with NDACC measurements over the same time period (0.30±0.04 %/year, averaged over 10 stations). Analysis of the GEOS-Chem-tagged simulation allows us to quantify the contribution of each tracer to the global methane change since 2005. We find that natural sources such as wetlands and biomass burning contribute to the interannual variability of methane. However, anthropogenic emissions, such as coal mining, and gas and oil transport and exploration, which are mainly emitted in the Northern Hemisphere and act as secondary contributors to the global budget of methane, have played a major role in the increase of atmospheric methane observed since 2005. Based on the GEOS-Chem-tagged simulation, we discuss possible cause(s) for the increase of methane since 2005, which is still unexplained. [less ▲]

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See detailÉléments de droit public (syllabus partiel 2016-17)
Bouhon, Frédéric ULg; Miny, Xavier ULg

Learning material (2017)

Ce document constitue un syllabus partiel à destination des étudiants de bachelier à HEC-ULg qui suivent le cours d'Introduction au droit, partim droit public. Il a vocation à être complété à l'avenir par ... [more ▼]

Ce document constitue un syllabus partiel à destination des étudiants de bachelier à HEC-ULg qui suivent le cours d'Introduction au droit, partim droit public. Il a vocation à être complété à l'avenir par d'autres chapitres. Le syllabus est complémentaire au cours oral et n'est pas un support obligatoire. [less ▲]

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See detailSur l'évaluation de compétences en mathématiques
Bair, Jacques ULg

E-print/Working paper (2017)

Ce document comprend deux parties. Tout d’abord, un texte est consacré à des généralités sur la mesure de compétences, ainsi qu’à la présentation, illustrée par des exemples concrets, de différents types ... [more ▼]

Ce document comprend deux parties. Tout d’abord, un texte est consacré à des généralités sur la mesure de compétences, ainsi qu’à la présentation, illustrée par des exemples concrets, de différents types d’échelles (universelle, descriptive, globale) et de grilles d’évaluation. Enfin, ce travail se termine par la reproduction de diapositives (initialement réalisées à l’aide du logiciel Power Point) préparées pour accompagner une leçon sur l’évaluation ; l’exposé oral correspondant a été donné, dans le cadre de la FOPED (Formation Pédagogique), à plusieurs cohortes de stagiaires en mathématiques à l’Université du Luxembourg. [less ▲]

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See detailLes marqueurs biologiques de l’arthrose: De la découverte à l’analyse biologique de routine
Henrotin, Yves ULg

in Rhumatos (2017), 14(123), 180-183

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See detailDrafting Choice of Law and Choice of Court Provisions under the EU Succession Regulation
Wautelet, Patrick ULg

in Conseil des Notariats de l'Union européenne (Ed.) L'europe pour les notaires - les notaires pour l'Europe - Formation 2015-2017 (2017)

This paper gives an overview of the possibilities offered by the European Succession Regulation (650/2012) to select the applicable law and the competent court. After a general overview, the attention ... [more ▼]

This paper gives an overview of the possibilities offered by the European Succession Regulation (650/2012) to select the applicable law and the competent court. After a general overview, the attention turns to specific topics such as the elements which need to be included in a choice of law provision, the impact of the existence of multiple nationalities, the choice of law in multi-jurisdictional countries, the impact of 'renvoi', and the relationship with third states. [less ▲]

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See detailThe constant of recognizability is computable for primitive morphisms
Durand, Fabien; Leroy, Julien ULg

in Journal of Integer Sequences (2017), 20(4),

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See detailDescription of patients consulting the voice clinic regarding gender, age, occupational status, and diagnosis
Remacle, Angélique ULg; Petitfils, Cloé; FINCK, Camille ULg et al

in European Archives of Oto-rhino-laryngology : Official Journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) (2017), 274(3), 1567-1576

Purpose. To describe the gender, age, occupational status and diagnosis of dysphonic patients. Method. We retrospectively analyzed the medical records of 1079 patients examined at the Voice clinic of the ... [more ▼]

Purpose. To describe the gender, age, occupational status and diagnosis of dysphonic patients. Method. We retrospectively analyzed the medical records of 1079 patients examined at the Voice clinic of the University hospital of Liège in French-speaking Belgium. Results. Overall, seven out of 10 patients who attended the voice clinic for dysphonia were females. The patients’ ages ranged from 4 to 93 (mean=43.5). Females predominantly consulted at the age of 54 and males at the age of 9. Regarding the occupational status, workers represented more than half of our patients (53%), while 11.2% were unemployed, 15.4% were students, and 19.9% were retired. Regarding the diagnoses of the 1079 patients, nodules were the most common pathologies (n=182, 16.9% of the patients), prevailing in females (n=142, 18.8% of the females), encountered in 16.8% of the workers and 42.8% of the students consulting the voice clinic. Following nodules, laryngeal mobility disorders were diagnosed in 16.4% of the patients (n=177), mainly females (n=115), and was the most frequent diagnosis in retirees (n=75, 34.9%). Conclusions. The majority of the patients consulting the voice clinic for dysphonia were adult females, in their workforce, diagnosed with vocal nodules. The identification of the patients’ characteristics and diagnoses is important to develop treatments and prevention of dysphonia, estimate their costs, and allow comparisons across referral centers. [less ▲]

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See detailA look at Intact Forest Landscapes and their relevance to Central African forest policy
Haurez, Barbara ULg; Daïnou, Kasso ULg; Vermeulen, Cédric ULg et al

Conference (2017, February)

Tropical forests are important providers of natural resources and ecosystem services but their ecological functions are facing increasing human pressure, linked to economic development. The preservation ... [more ▼]

Tropical forests are important providers of natural resources and ecosystem services but their ecological functions are facing increasing human pressure, linked to economic development. The preservation of tropical forest ecosystems is interrelated with effective land use planning and identification of priority areas for conservation. Initially defined by Greenpeace and the World Resources Institute (WRI) in 2000, Intact Forest Landscapes (IFLs) are large areas of forest minimally impacted by human activities. IFLs were identified by mapping industrial activities, road networks and infrastructure using remote sensing. Since 2014, when IFLs were recognized and adopted by the certification scheme Forest Stewardship Council (FSC), the IFLs have become integrated into forest management policies. In order to trace the history and evaluate the applicability of IFLs for forest management policy in the Central African context, we searched for documents related to the IFL method, and previous similar concepts. The IFL method is simple and cost-effective and enables the monitoring of forest degradation at a global scale. However, the approach mainly considers forest cover and is imprecise at the local scale. For example, hunting, one of the main threats faced by Central African ecosystems, cannot be detected by satellite imagery and is therefore disregarded in IFL identification processes. In contrast, there are other considered anthropogenic activities, such as reduced-impact selective logging, which may be compatible with forest ecosystem conservation. To better tailor the IFL approach to Central African forests, we recommend (i) the consideration of wildlife communities distribution in the analysis of disturbance, (ii) a thorough evaluation of the impacts of different human activities on forest ecosystems, and (iii) the integration of local stakeholders and governments in the design of land management strategies devised to address social, economic and environmental needs. [less ▲]

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See detailMontée des eaux : Un nouveau modèle de simulation climatique
Wyard, Coraline ULg; Fettweis, Xavier ULg

Article for general public (2017)

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See detailLa littérature belge francophone en classe de FLE
Outers, Pierre ULg; Stilmant, Nicolas

in Bulletin SUF (2017), 89

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See detailEcological intensification of fish production : Fertilization strategies in Africa fish farms
Mafwila Kinkela, Patrick ULg; Kambashi Mutiaka, Bienvenu ULg; Rollin, Xavier et al

Poster (2017, February)

Ponds fertilization has been found as strategies of intensification fish production for farm in Africa were commercial feeds are not available and ingredients for formulate completed feed are cost ... [more ▼]

Ponds fertilization has been found as strategies of intensification fish production for farm in Africa were commercial feeds are not available and ingredients for formulate completed feed are cost. However, farmers are not safe to any danger because the efficiency of these strategies is not always known owing to the associated risk of eutrophication. An experience was making to assess how various fertilization practices would impact fish growth and physicochemical parameters of water in the pond. [less ▲]

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See detailLe rôle des rongeurs dans la dispersion des diaspores en milieu forestier (synthèse bibliographique)
Evrard, Quentin ULg; Haurez, Barbara ULg; Doucet, Jean-Louis ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (2017)

Introduction. Seed dispersal is a key interaction that influences a number of ecological processes that are important to the maintenance of diversity in forest ecosystems. Rodents, mainly considered as ... [more ▼]

Introduction. Seed dispersal is a key interaction that influences a number of ecological processes that are important to the maintenance of diversity in forest ecosystems. Rodents, mainly considered as seed predators, can carry, hide and discard seeds, often transporting them over considerable distances from the parent tree and thus leading to an enhanced germination rate. The role of rodents on forest regeneration therefore depends upon several environmental variables influencing their behavior. Literature. Many publications demonstrate that rodents are mostly seed predators for many species. Nevertheless, because it is hard to define their movement pattern, the role of rodents on regeneration could be underestimated. Through scatter-hoarding, rodents may play a crucial role, particularly in those forests where anthropogenic pressures have led to a reduction in the density of large mammals. However, very few studies have been conducted in African moist forests where defaunation can be high, and the role of rodents has been very poorly studied. Conclusions. To understand the phenomenon, we suggest to further investigate the interactions between seeds and rodents by employing methods that have been commonly used on other continents. [less ▲]

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See detailFlutter and limit cycle oscillation suppression using linear and nonlinear tuned vibration absorbers
Verstraelen, Edouard ULg; Kerschen, Gaëtan ULg; Dimitriadis, Grigorios ULg

in Proceedings of the SEM IMAC XXXV (2017, February)

Aircraft are more than ever pushed to their limits for performance reasons. Consequently, they become increasingly nonlinear and they are more prone to undergo aeroelastic limit cycle oscillations ... [more ▼]

Aircraft are more than ever pushed to their limits for performance reasons. Consequently, they become increasingly nonlinear and they are more prone to undergo aeroelastic limit cycle oscillations. Structural nonlinearities affect aircraft such as the F-16, which can undergo store-induced limit cycle oscillations (LCOs). Furthermore, transonic buzz can lead to LCOs because of moving shock waves in transonic flight conditions on many aircraft. This study presents a numerical investigation of passive LCO suppression on a typical aeroelastic system with pitch and plunge degrees of freedom and a hardening stiffness nonlinearity. The absorber used is made of a piezoelectric patch glued to the plunge springs and connected to a resistor and an inductance forming a RLC circuit. A mechanical tuned mass damper absorber of similar configuration is also considered. The piezoelectric absorber features significant advantages in terms of size, weight and tuning convenience. The results show that both types of absorber increase the linear flutter speed of the system in a similar fashion but, when optimal, they lead to a sub-critical bifurcation while a super-critical bifurcation was observed without absorber. Finally, it is shown that the addition of a properly tuned nonlinear spring (mechanical absorber) or capacitor (piezo- electric absorber) can restore the super-criticality of the bifurcation. The tuning of the nonlinearity is carried out using numerical continuation. [less ▲]

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See detailCrossoads (Fevrier 2017) - chaque mercredi de 18h à20h - rediffusion: samedis de 22h à min
Sacré, Robert ULg

Diverse speeche and writing (2017)

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See detailEvaluation of the ruminal function of Belgian dairy cows suspected of subacute ruminal acidosis.
Lessire, Françoise ULg; Knapp, Emilie; Theron, Léonard et al

in Vlaams Diergeneeskundig tijdschrift (2017), 86(1), 16-23

Subacute ruminal acidosis (SARA) has been considered a major pathology in high producing dairy herds for years. These findings were corroborated by several studies in Europe. However, different feeding ... [more ▼]

Subacute ruminal acidosis (SARA) has been considered a major pathology in high producing dairy herds for years. These findings were corroborated by several studies in Europe. However, different feeding practices and herds’ production levels are found in Southern Belgium. This study aimed to ascertain whether dairy cows of several herds from the south of Belgium (Wallonia) with a suspicion of SARA really did present too low ruminal pH values. Twenty-four herds were visited and 172 cows were sampled using an oropharyngeal device to collect ruminal fluid, i.e. Geishauser probe. On the samples, three tests were performed: pH measurement, methylene blue reduction test and microscopic evaluation of protozoa vitality. Based on these analyses, no cows demonstrated pH values lower than 5.5 and, only ten cows could be considered at risk for SARA. By contrast, in eightteen cows, pH values higher than 7.0 were measured and ruminal inactivity was suspected. In this study, ruminal alkalosis appeared to be more frequently observed than SARA. [less ▲]

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