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See detailEffects of concentrate level on milk production and traffic of grazing cows milked by a mobile automatic milking system on pasture
Lessire, Françoise ULg; Hornick, Jean-Luc ULg; Dufrasne, Isabelle ULg

in Hopkins, Alan; Collins, Rosemary; Fraser, Marieacia (Eds.) et al EGF at 50: The future of European Grasslands (2014, September 10)

Cows milked by an automatic milking system in pastures were assigned in 2 groups receiving different amounts of concentrates (2.1 kg vs 4.1 kg). The effect of concentrates’ level on milk yield (MY) and ... [more ▼]

Cows milked by an automatic milking system in pastures were assigned in 2 groups receiving different amounts of concentrates (2.1 kg vs 4.1 kg). The effect of concentrates’ level on milk yield (MY) and returns to the robot was assessed. Concentrates’ level had a positive influence on daily milk production over the grazing period as cows of low concentrates group produced 21.43 ± 0.62 kg compared with 24.33 ± 0.62 kg in high concentrates group. However this effect was modulated subsequently to grass quality and availability. Regarding daily voluntary returns to the robot, high concentrates group showed higher frequency (3.66 ± 0.05, compared with 3.22 ± 0.04 in low concentrates group) demonstrating positive impact of complement distribution on cows’ traffic. [less ▲]

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See detailEffects of mild heat stress periods on milk production, milking frequency and rumination time of grazing cows milked by an automatic milking system
Lessire, Françoise ULg; Hornick, Jean-Luc ULg; Dufrasne, Isabelle ULg

in Hopkins, A; Collins, Rosemary; Fraser, Mariecia (Eds.) et al EGF at 50: The future of European grasslands (2014, September 10)

Grazing dairy cows milked by an automatic system (AS) experienced mild heat stress (HS) periods, twice during the summer. The daily temperature humidity index (THI) during these periods were higher than ... [more ▼]

Grazing dairy cows milked by an automatic system (AS) experienced mild heat stress (HS) periods, twice during the summer. The daily temperature humidity index (THI) during these periods were higher than 72. Milk production, as well as milking frequency, rumination time and milk fat to protein ratio (F/P) during these periods were compared to adjacent periods with mean THI of 61. The daily milking frequency, the total number of visits to AS and the milk production were significantly higher in HS periods (2.12 vs 1.97, 2.99 vs 2.69, and 19.7 vs 18.5 kg milk per cow, respectively). There were significant interactions between times and periods for milking frequency and number of visits, while the daily rumination time was significantly lower (339 vs 419 min) and the F/P in milk tended to be decreased (1.17 vs 1.23). These results could be explained by changes in cow behaviour during HS periods. [less ▲]

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See detailEffects of concentrate level on milk production and traffic of grazing cows milked by a mobile automatic milking system on pasture
Lessire, Françoise ULg; Hornick, Jean-Luc ULg; Dufrasne, Isabelle ULg

in Hopkins, Alan; Collins, Rosemary; Fraser, Marieacia (Eds.) et al EGF at 50: The future of European Grasslands (2014, September 10)

Cows milked by an automatic milking system in pastures were assigned in 2 groups receiving different amounts of concentrates (2.1 kg vs 4.1 kg). The effect of concentrates’ level on milk yield (MY) and ... [more ▼]

Cows milked by an automatic milking system in pastures were assigned in 2 groups receiving different amounts of concentrates (2.1 kg vs 4.1 kg). The effect of concentrates’ level on milk yield (MY) and returns to the robot was assessed. Concentrates’ level had a positive influence on daily milk production over the grazing period as cows of low concentrates group produced 21.43 ± 0.62 kg compared with 24.33 ± 0.62 kg in high concentrates group. However this effect was modulated subsequently to grass quality and availability. Regarding daily voluntary returns to the robot, high concentrates group showed higher frequency (3.66 ± 0.05, compared with 3.22 ± 0.04 in low concentrates group) demonstrating positive impact of complement distribution on cows’ traffic. [less ▲]

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See detailPressure-impulse diagram of a beam under explosion - Influence of the indirectly affected part
Hamra, Lotfi ULg; Demonceau, Jean-François ULg; Denoël, Vincent ULg

in Landolfo, Raffaele; Mazzolani, Frederico (Eds.) Proceeding of the 7th European conference on steel and composite structures (Eurosteel 2014) (2014, September 10)

The paper studies the structural response of a beam subjected to a close-field local internal blast loading. In the literature, the pressure-impulse (p-I) diagram is commonly used to design elements or ... [more ▼]

The paper studies the structural response of a beam subjected to a close-field local internal blast loading. In the literature, the pressure-impulse (p-I) diagram is commonly used to design elements or structures for a given blast loading. The p-I diagram is a spectrum representing the level sets of damage or required ductility for a given structural system, nonlinear beam in this paper. This representation is much appreciated because a simple reading for the actual pressure p and impulse I of the considered load indicates the ductility demand of the structural system. Recent works of quasi-static behaviour have indicated the crucial need to account for the membrane effects taking place in the extreme loading of frame beams. This paper will thus extend the state-of-art features, establishing thus the p-I diagram for a beam including the lateral restraints offered by the rest of the structure, the development of non-linear membrane action and also, the M-N interaction that develops in the plastic hinges. [less ▲]

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See detailEffects of concentrate level on milk production and traffic of grazing cows milked by a mobile automatic milking system on pasture
Lessire, Françoise ULg; Hornick, Jean-Luc ULg; Dufrasne, Isabelle ULg

in Hopkins, Alan; Collins, Rosemary; Fraser, Marieacia (Eds.) et al EGF at 50: The future of European Grasslands (2014, September 10)

Cows milked by an automatic milking system in pastures were assigned in 2 groups receiving different amounts of concentrates (2.1 kg vs 4.1 kg). The effect of concentrates’ level on milk yield (MY) and ... [more ▼]

Cows milked by an automatic milking system in pastures were assigned in 2 groups receiving different amounts of concentrates (2.1 kg vs 4.1 kg). The effect of concentrates’ level on milk yield (MY) and returns to the robot was assessed. Concentrates’ level had a positive influence on daily milk production over the grazing period as cows of low concentrates group produced 21.43 ± 0.62 kg compared with 24.33 ± 0.62 kg in high concentrates group. However this effect was modulated subsequently to grass quality and availability. Regarding daily voluntary returns to the robot, high concentrates group showed higher frequency (3.66 ± 0.05, compared with 3.22 ± 0.04 in low concentrates group) demonstrating positive impact of complement distribution on cows’ traffic. [less ▲]

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See detailAdaptation interculturelle et validation du questionnaire VISA-P en français
Oppong-Kyei, Julian; Bruyère, Olivier ULg; Delvaux, François ULg et al

in 7ème Congrès National SFMES & SFTS 2014 (2014, September)

Introduction La tendinopathie patellaire est une affection musculo-squelettique très fréquentes chez le sportif et la plus fréquente au niveau du genou. Elle affecte le plus souvent des disciplines qui ... [more ▼]

Introduction La tendinopathie patellaire est une affection musculo-squelettique très fréquentes chez le sportif et la plus fréquente au niveau du genou. Elle affecte le plus souvent des disciplines qui nécessitent soit des impulsions et des sauts soit un travail important du quadriceps. Le Victorian Institute of Sports Assessment–Patellar (VISA-P) est un questionnaire permettant d’évaluer les symptômes et leurs retentissements sur les activités physiques quotidiennes et sportives de la tendinopathie patellaire (Jumper’s knee). Comme la plus part des questionnaires de ce type, le VISA-P fut originalement développé pour des patients anglophones et n'est donc pas adapté à une population francophone. En conséquence, l'objectif de cette étude sera de traduire, adapter et valider une version française fiable du VISA-P et d'en évaluer ses propriétés psychométriques. Matériel et méthode La traduction et l’adaptation interculturelle du VISA-P ont été réalisées selon les recommandations internationales (Guidelines for the Process of Cross-Cultural Adaptation of Self-Report Measures). Ce processus s'est déroulé en 6 étapes : traductions initiales, synthèse des traductions, traduction de retour vers la langue d’origine, comité expert, test de la version pré-finale et approbation du comité expert. La version française finale obtenue fut ensuite l’objet d’une évaluation de certaines propriétés psychométriques telles que la fidélité test-retest, la cohérence interne, la validité de construit et les effets plancher et plafond. Nonante-deux sujets furent recruté au total afin de tester ces propriétés psychométriques. Trois groupes de sujets furent utilisés pour répondre conjointement aux VISA-P et à un questionnaire supplémentaire, le Medical Outcomes Survey Short Form 36 questionnaire (SF-36) pour la validité de construit : un groupe de sujets pathologiques principalement recrutés parmi les patients du Centre Hospitalier Universitaire de Liège (28), un groupe de sujets asymptomatiques (22) et un groupe de sportifs à risque recrutés dans divers clubs sportif (42). L'ensemble des participants ont été recrutés au sein de la province de Liège. Résultats Aucun sujet ne présenta de grosses difficultés à comprendre le questionnaire suite au test de la version pré-finale. Les différents membres du comité expert se montrèrent satisfait de la version finale et donnèrent donc leur approbation. La moyenne des scores obtenu est de 53 (± 17) pour le groupe pathologique, 99 (± 2) pour le groupe sain et 86 (± 14) pour le groupe à risque. Les corrélations entre le VISA-P et certaines mesures divergentes du SF-36 semblent donner des résultats faibles. Les coefficients de corrélation mesurés entre les scores du VISA-P et les items convergents du SF-36 paraissent être élevés. Aucun effet plancher ou plafond n'a pu être observer lors de l'évaluation des propriétés psychométriques du VISA-P dans le groupe pathologique. Conclusion La version française du VISA-P est donc être un questionnaire compréhensible, fiable et adapté aux patients francophones souffrant d'une tendinopathie patellaire supérieur. [less ▲]

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See detailImpact de la médiatisation technologique sur la mobilisation des modalités non-verbales dans les références démonstratives.
Defays, Aurore ULg; Jeunejean, Aurélie ULg; Giboin, Alain

in Leclercq, Pierre; Bonnet, Pierre; Dondero, Maria Giulia (Eds.) et al COMMON 14 - Communication multimodale et collaboration instrumentée (2014, September)

L’objectif de ce papier est de comprendre comment la médiatisation technologique et les contraintes d’utilisation d’un outil vont modifier la manière dont les agents vont mobiliser les modalités de ... [more ▼]

L’objectif de ce papier est de comprendre comment la médiatisation technologique et les contraintes d’utilisation d’un outil vont modifier la manière dont les agents vont mobiliser les modalités de communications pour collaborer efficacement. Dans ce travail, nous nous sommes centrés sur les références démonstratives, c’est-à-dire les références verbales qui nécessitent d’être accompagnées de gestes pour que leur interprétation soit complète. Nous avons mené cette recherche dans le domaine de la conception architecturale et avons examiné deux situations de travail collaboratif (une en coprésence et une outillée) dans le but de pouvoir les comparer. Pour chaque situation, nous décrivons comment les architectes s’adaptent aux modalités potentiellement disponibles pour désigner l’objet à quoi ils font référence dans leur discours. Nos résultats montrent que lorsque la modalité gestuelle ne peut être utilisée de manière effective, comme c’est le cas dans la situation outillée, les architectes vont développer des stratégies de compensation. En effet, la modalité graphique va pallier la transmission partielle des gestes en prenant le relais de la fonction de désignation. [less ▲]

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See detailAdaptation interculturelle et validation du questionnaire VISA-A en français
Oppong-Kyei, Julian; Bruyère, Olivier ULg; Delvaux, François ULg et al

in 7ème Congrès National SFMES & SFTS 2014 (2014, September)

Introduction La tendinopathie d’Achille, dont la discipline athlétique implique une grosse activité de course à pied, représente une source de douleurs et de handicap. Cette pathologie fait actuellement l ... [more ▼]

Introduction La tendinopathie d’Achille, dont la discipline athlétique implique une grosse activité de course à pied, représente une source de douleurs et de handicap. Cette pathologie fait actuellement l'objet de nouvelles découvertes sur le plan de la physiopathologie permettant l'exploration de nouvelles pistes thérapeutiques. Dans le cadre de telles études, des échelles d’évaluation sont utilisées afin d'évaluer des phénomènes subjectifs ou complexes tels la douleur, la qualité de vie, le handicap, etc. Elles sont généralement composées de plusieurs items dont la cotation est combinée en un score global ou des sous scores dimensionnels. La majorité des échelles algo-fonctionnelles sont développés dans des pays anglophones et sont par conséquence uniquement pertinents pour des sujets parlant l’anglais. Ceci est la cas pour le Victorian Institute of Sports Assessment–Achilles (VISA-A), un questionnaire développé dans le but d'évaluer la sévérité des symptômes de la tendinopathie achilléenne. L’intérêt de ce mémoire est donc de valider une version française fiable de ce questionnaire. Matériel et méthode La traduction et l’adaptation interculturelle du VISA-A ont été réalisées selon les recommandations internationales (Guidelines for the Process of Cross-Cultural Adaptation of Self-Report Measures). Ce processus s'est déroulé en 6 étapes : traductions initiales, synthèse des traductions, traduction de retour vers la langue d’origine, comité expert, test de la version pré-finale et approbation du comité expert. La version française finale obtenue fut ensuite l’objet d’une évaluation de certaines propriétés psychométriques telles que la fidélité test-retest, la cohérence interne, la validité de construit et les effets plancher et plafond. Pour ces évaluations, 116 sujets furent recruté et répartis en 3 groupes : un groupe de sujets pathologiques principalement recrutés parmi les patients du Centre Hospitalier Universitaire de Liège (31), un groupe de sujets asymptomatiques (22) et un groupe de sportifs à risque (63). Tous ces sujets durent également répondre à un questionnaire supplémentaire, le Medical Outcomes Survey Short Form 36 questionnaire (SF-36) pour la validité de construit. L'ensemble des participants ont été recrutés au sein de la province de Liège. Résultats Aucun sujets ne présenta de difficultés à comprendre le questionnaire suite au test de la version pré-finale. Les différents membres du comité expert se montrèrent satisfait de la version finale et donnèrent donc leur approbation. La moyenne des scores obtenus dans le groupe pathologique est de 59 (± 18), celle du groupe sain est de 99 (± 1) et celle du groupe à risque est de 94 (± 7). Aucun effet plancher ou plafond n'a pu être observer lors de l'évaluation des propriétés psychométriques du VISA-A (dans le groupe pathologique). Les corrélations entre le VISA-A et certaines mesures divergentes du SF-36 semblent être faibles. Les coefficients de corrélation mesurés entre les scores du VISA-A et les items convergents du SF-36 paraissent être élevé. Conclusion La version française du VISA-A est donc être un questionnaire compréhensible, fiable et adapté aux patients francophones souffrant d'une tendinopathie d'Achille. [less ▲]

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See detailHow to check analytically the robustness of a building submitted to a column loss - A premiere
Huvelle, Clara ULg; Jaspart, Jean-Pierre ULg; Demonceau, Jean-François ULg

in Proceedings of Eurosteel 2014 conference (2014, September)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to Eurocodes and some ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to Eurocodes and some other national design codes, the structural integrity of civil engineering structures should be guaranteed through appropriate measures and one way to guarantee it is to ensure an appropriate robustness of the structure, which may be defined as the ability of a structure to remain globally stable in case of exceptional event leading to local damages. However, although global design approaches are provided in modern codes and standards, no easy-to-apply practical guidelines are provided. The present paper reflects recent researches realised at the University of Liege with the scope of proposing such practical guidelines for the activation of alternative load path in the structure, design strategy generally leading to the most economical solutions. [less ▲]

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See detailAbelian bordered factors and periodicity
Charlier, Emilie ULg; Harju, Tero; Puzynina, Svetlana et al

in Actes des Journées Montoises d'Informatique Théorique (2014, September)

A finite word is bordered if it has a non-empty proper prefix which is equal to its suffix, and unbordered otherwise. Ehrenfeucht and Silberger proved that an infinite word is (purely) periodic if and ... [more ▼]

A finite word is bordered if it has a non-empty proper prefix which is equal to its suffix, and unbordered otherwise. Ehrenfeucht and Silberger proved that an infinite word is (purely) periodic if and only if it contains only finitely many unbordered factors. We are interested in an abelian modification of this fact. Namely, we have the following question: Let w be an infinite word such that all sufficiently long factors are abelian bordered. Is w (abelian) periodic? We also consider a weakly abelian modification of this question, when only the frequencies of letters are taken into account. Besides that, we answer a question of Avgustinovich, Karhumaki and Puzynina concerning abelian central factorization theorem. [less ▲]

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See detailApplication of X-ray microtomography to investigate the effect of raw material properties on the kinetics of iron ores granulation
Contreras, Rafael; Evrard, Maxime ULg; Van loo, Frederic et al

in PSA 2014 Manchester- Abstracts (2014, September)

In modern ironmaking, granulation is the first step of the sintering process. It is typically carried out in continuous drum granulators using water as a binder, and involves multiple components besides ... [more ▼]

In modern ironmaking, granulation is the first step of the sintering process. It is typically carried out in continuous drum granulators using water as a binder, and involves multiple components besides iron ores, such as return fines and other recycled materials (dusts, mill scale, sludges), solid fuel (coke breeze or anthracite) and fluxes (limestone, lime, olivine, dunite or dolomite) (Ball, 1973). As it is necessary to maintain a consistent quality of the granules (size distribution, porosity, strength, etc.) despite of the varying iron ore origins, the question arises as to how the properties of the iron ore particles (size and shape) influence the granulation process. The granulation process is partly influenced by the characteristic of the feed and partly by the action of cohesive force inside the drum granulator (Newitt et al. 1958). The objective of this paper is to study the effect of raw material properties on the kinetics of iron ore granulation considering in particular the mechanisms ruling wet granulation for two iron ores and to know the factors which determine the texture, shape, porosity and mechanical strength of the granules. [less ▲]

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See detailClinical and genetic aspects of familial isolated pituitary adenomas
Beckers, Albert ULg

in Abstract book - 14th International Workshop on Multiple Endocrine Neoplasia and other rare endocrine tumors (2014, September)

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See detailBOLTED END-PLATE BEAM-TO-COLUMN JOINTS USING HAMMERHEAD BEAMS: Experimental tests and proposal of design guidelines
Demonceau, Jean-François ULg; Hoang, Van Long ULg; Jaspart, Jean-Pierre ULg

in Landolfo, Raffaele; Mazzolani, Frederico (Eds.) Proceeding of the 7th European conference on steel and composite structures (Eurosteel 2014) (2014, September)

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See detailPituitary gland in MEN1 syndrome : from histopathology to prognosis
Villa, C; Bernier, M; Gaillard, S et al

in Abstract book - 14th International Workshop on Multiple Endocrine Neoplasia and other rare endocrine tumors (2014, September)

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See detailThe efficiency of different simulation-based design methods in improving building performance
Nguyen, Anh Tuan; Reiter, Sigrid ULg

in Brebbia,, C.A.,; Pulselli, R. (Eds.) WIT Transactions on Ecology on The Built Environment, vol. 142 (2014, September)

This paper presents a pioneering effort to define the efficiency of the most common simulation-based design methods, namely the parametric simulation method (PSM) and the simulation-based optimization ... [more ▼]

This paper presents a pioneering effort to define the efficiency of the most common simulation-based design methods, namely the parametric simulation method (PSM) and the simulation-based optimization method (SOM), in improving two building performance indicators: thermal comfort and energy consumption. Three case-study houses were selected and their indoor conditions were continuously monitored during one summer month in 2012. Computer EnergyPlus models of these houses were established and then carefully calibrated by the monitoring data to improve the reliability of the numerical methods. Thermal performances of these houses during a year were simulated, then improved by the PSM and finally optimized by the SOM. By comparing the results of these two simulation-based design methods, this research found that both the PSM and SOM were very effective in improving these building performance indicators. This study found that the SOM is almost two times more efficient than the PSM in improving thermal comfort in naturally ventilated (NV) houses and life cycle cost in air-conditioned (AC) houses. In average, the discomfort period in NV houses could be reduced by 44.9% by the PSM while as high as 86.1% by the SOM, compared with the reference cases. The life cycle cost of AC houses had smaller reductions with 6.2% and 14.6% cut-off by the PSM and SOM, respectively. The results of this work give a strong and explicit insight of the actual efficiency of each design method. This work also shows great advantages of applications of advanced numerical approaches in the design of high performance buildings. [less ▲]

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See detailDetection of Angiostrongylus vasorum in the bronchoalveolar lavage fluid or faeces of coughing and healthy dogs in Belgium.
Canonne-Guibert, Morgane ULg; Roels, Elodie ULg; Caron, Yannick ULg et al

in Proceedings of the 24th Ecvim Meeting, Mainz, Germany - 4-6 September 2014 (2014, September)

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See detailExperimental evidence and numerical prediction of nonlinear modal interactions in a real-life aerospace structure
Renson, Ludovic ULg; Noël, Jean-Philippe ULg; Kerschen, Gaëtan ULg

in Proceedings of the ISMA 2014 conference (2014, September)

During the last decade, the existence of nonlinear behaviour in spacecraft dynamic testing was frequently attested. However, current practice in industry is still to ignore nonlinearities, arguably ... [more ▼]

During the last decade, the existence of nonlinear behaviour in spacecraft dynamic testing was frequently attested. However, current practice in industry is still to ignore nonlinearities, arguably because their analysis is regarded as impractical. The objective of the present contribution is to show that there now exists experimental and numerical methodologies which can deal with nonlinear phenomena in real-life structures. Specifically, this study investigates nonlinear modal interactions evidenced during the qualification campaign of the SmallSat spacecraft developed by EADS-Astrium. The ability to understand and reliably predict such interactions is of utmost importance as they may involve energy transfer between modes and, in turn, jeopardise the structural integrity. The paper proceeds in two steps, leading to great-fidelity reproductions of the experimental observations. In the first step, sine-sweep data collected during the qualification campaign are exploited to build a nonlinear computational model of the SmallSat with good predictive capabilities. To this end, the complete progression through nonlinearity detection, characterisation and parameter estimation is carried out by means of several techniques, such as the wavelet transform and the restoring force surface method. In the second step, the computational model is exploited through continuation algorithms to compute the nonlinear normal modes of the spacecraft and predict potential interactions. A very good agreement between experimental and numerical results is obtained for 2:1 interactions between modes with non-commensurate linear frequencies. [less ▲]

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See detailNIR interferometric observations of massive hierarchical triple systems: Tr16-104 and HD150136
Gosset, Eric ULg; Le Bouquin, Jean-Baptiste; Absil, Olivier ULg et al

in de Grijs, Richard (Ed.) Binary Systems: their Evolution and Environments (2014, September)

We report on an observational astrometric study of the orbit of the tertiary stars in two massive hierarchical triple systems. The work is complemented by radial velocity data with the aim of deriving the ... [more ▼]

We report on an observational astrometric study of the orbit of the tertiary stars in two massive hierarchical triple systems. The work is complemented by radial velocity data with the aim of deriving the full 3D orbit and constraints on the orbital planes. This is the first report of the tertiary star's detection for Tr16-104. The work is a natural extension of the search for binaries among massive O-stars. The basic motivation of the study of hierarchical triple systems is the determination of the masses of the individual components and the derivation of the relative orientation of the two orbital planes, with the ultimate aim of understanding the related star formation processes. [less ▲]

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See detailThe freeness problem for products of matrices defined on bounded languages
Charlier, Emilie ULg; Honkala, Juha

in Actes des Journées Montoises d'Informatique Théorique (2014, September)

In this talk, I presented a joint work with Juha Honkala. We study the freeness problem for matrix semigroups. We show that the freeness problem is decidable for upper-triangular 2x2 matrices with ... [more ▼]

In this talk, I presented a joint work with Juha Honkala. We study the freeness problem for matrix semigroups. We show that the freeness problem is decidable for upper-triangular 2x2 matrices with rational entries when the products are restricted to certain bounded languages. We also show that this problem becomes undecidable for large enough matrices. [less ▲]

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See detailFlow and turbulence characterization as an onset for assessing the stability of gravel beds
Duma, Diana ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in 7th International Conference on Fluvial Hydraulics (2014, September)

The flow characteristics, such as velocity profiles and turbulence intensities, are of high practical relevance in the assessment of riverbed stability. So far, the Shields diagram remains the most widely ... [more ▼]

The flow characteristics, such as velocity profiles and turbulence intensities, are of high practical relevance in the assessment of riverbed stability. So far, the Shields diagram remains the most widely accepted approach for defining the initiation of sediment motion. However, it faces a number of shortcomings. In principle, it is only valid for uniform flow conditions and, under non-uniform flow conditions, it fails to account properly for the influence of turbulence in sediment entrainment. In this paper, we focus on a more detailed description of quasi-uniform and non-uniform flow characteristics in the vicinity of the critical flow conditions for inception of motion of gravel beds. Laboratory experiments were designed, involving two configurations. First, the entire bottom of the flume was paved with stones of uniform diameter (8 or 15 mm), leading to quasi-uniform flow conditions. Second, the flume bottom was smooth upstream of the zone of measurement while the downstream part was covered with gravels, leading to a sudden smooth-to-rough transition. The flow velocity was obtained by acoustic measurements and the turbulence intensity was calculated for both configurations. By fitting the velocity profile to a modified logarithmic law, the shear velocity was estimated. Standard approaches for predicting the threshold of motion, initially developed for uniform flows, were compared to other methods, based on depth-averaged turbulence kinetic energy, recently proposed in literature for non-uniform flow conditions. [less ▲]

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See detailCorrelation between thoracic ct-scan angiography findings and echocardiographic right pulmonary vein to pulmonary artery ratio in west highland white terriers with idiopathic pulmonary fibrosis.
Roels, Elodie ULg; Merveille, Anne-Christine ULg; Couvreur, T. et al

in Proceedings of the 24th Ecvim Meeting, Mainz, Germany - 4-6 September 2014 (2014, September)

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See detailImpact of Circularity Defect of Helical Fillets HDPE Bridge Stay Covers: Analysis of Bi-Stability at Critical Reynolds Number by Bifurcation Diagrams
Benidir, Adel; Flamand, Olivier; Gaillet, Laurent et al

in Proceedings of the Symposium on the Dynamics and Aerodynamics of Cables - SDAC 2014 (2014, September)

Dry galloping of cables is still considered by the scientific community as an important phenomenon lacking investigation on cable stayed bridge. The helical fillet cylinders developed to overcome the Rain ... [more ▼]

Dry galloping of cables is still considered by the scientific community as an important phenomenon lacking investigation on cable stayed bridge. The helical fillet cylinders developed to overcome the Rain-Wind Induced Vibration (RWID) were reported to be affected by the appearance of vibration in dry conditions. This paper focuses on a method developed to process data issued from wind tunnel tests on original High Density Polyethylene (HDPE) cable covers with helical fillets, in a range of Reynolds numbers from the sub-critical regime to the critical regime. Corresponding values range from Re = 9.6x10^4 to Re = 3.6x10^5 for the present work. The experiment consists of investigating the effect of the helical fillets with natural or controlled deformation of his circularity defect. Previous studies ([1], [3] and [4]) reported that dry galloping is caused by the appearance of a negative pressure bubble on one side of a circular cylinder at the critical Reynolds number range, leading to a rapid drop in the drag coefficient and the appearance of a non negligible lift force. Because the flow oscillates between two states, say TrBL0 and TrBL1, giving way to a fluctuating lift force supposed to cause the vibration of cables. However, [1] reports that the TrBL1 regime disappears in the presence of helical fillets. The aim of the current study was to investigate a possible appearance of the TrBL1 regime when the circularity defect threshold exceeds the filet thickness. In this case, the second purpose was to characterize the bi-stability of this phenomenon and provide new tools for wind engineering processing. [less ▲]

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See detailThe efficiency of different simulation-based design methods in improving building performance
Nguyen, Anh Tuan; Reiter, Sigrid ULg

in Brebbia,, C.A.,; Pulselli, R. (Eds.) WIT Transactions on Ecology on The Built Environment, vol. 142 (2014, September)

This paper presents a pioneering effort to define the efficiency of the most common simulation-based design methods, namely the parametric simulation method (PSM) and the simulation-based optimization ... [more ▼]

This paper presents a pioneering effort to define the efficiency of the most common simulation-based design methods, namely the parametric simulation method (PSM) and the simulation-based optimization method (SOM), in improving two building performance indicators: thermal comfort and energy consumption. Three case-study houses were selected and their indoor conditions were continuously monitored during one summer month in 2012. Computer EnergyPlus models of these houses were established and then carefully calibrated by the monitoring data to improve the reliability of the numerical methods. Thermal performances of these houses during a year were simulated, then improved by the PSM and finally optimized by the SOM. By comparing the results of these two simulation-based design methods, this research found that both the PSM and SOM were very effective in improving these building performance indicators. This study found that the SOM is almost two times more efficient than the PSM in improving thermal comfort in naturally ventilated (NV) houses and life cycle cost in air-conditioned (AC) houses. In average, the discomfort period in NV houses could be reduced by 44.9% by the PSM while as high as 86.1% by the SOM, compared with the reference cases. The life cycle cost of AC houses had smaller reductions with 6.2% and 14.6% cut-off by the PSM and SOM, respectively. The results of this work give a strong and explicit insight of the actual efficiency of each design method. This work also shows great advantages of applications of advanced numerical approaches in the design of high performance buildings. [less ▲]

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See detailCalibration of Building Simulation Models: Assessment of Current Acceptance Criteria
Ruiz Flores, Roberto ULg; Lemort, Vincent ULg

in Proceedings of the 8th International Conference Improving Energy Efficiency in Commercial Buildings (IEECB’14) (2014, September)

In this paper, the most used acceptance criteria in calibration of building simulation models are introduced and tried out by means of a practical exercise. In order to simplify the process of obtaining ... [more ▼]

In this paper, the most used acceptance criteria in calibration of building simulation models are introduced and tried out by means of a practical exercise. In order to simplify the process of obtaining “simulated data” and to avoid carrying out a formal calibration procedure; two yearly testing profiles (hourly time scale) are created from real building electrical metered data (¼ hour profile). Both testing profiles represent two model responses that could possibly be obtained in a common calibration procedure. The objective of this work is to test the capabilities of the method to determine (1) the model adequacy to represent an existing situation; (2) the reliability of the model when predicting a future or different scenario and also (3) the ability of the method to orient the practitioner to upgrade the model when it provides a non-satisfactory response. To do this, the real accuracy of both testing profiles is verified by means of a complementary statistical bin analysis. This crosschecking analysis allows highlighting the strengths and weakness of the current criteria and determining whether they need to be revised, modified or complemented. At the end of the analysis, it is concluded that the capabilities of the current acceptance criteria are limited because don’t provide any satisfactory answer, indication or clue for none of the three points aforementioned and some other complementary tests (such as bin analysis) must be implemented and performed in order to properly declare a model as calibrated. [less ▲]

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See detailVascular endothelial growth factor : a blood biomarker in canine pulmonary fibrosis.
Roels, Elodie ULg; Krafft, Emilie ULg; Heikkilä, H.P. et al

in Proceedings of the 24th Ecvim Meeting, Mainz, Germany - 4-6 September 2014 (2014, September)

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See detailIntérêt d’une seconde infiltration de plasma riche en plaquettes dans le traitement des tendinopathies patellaires ?
Kaux, Jean-François ULg; Croisier, Jean-Louis ULg; Buhler, Frédéric et al

in 7ème Congrès National SFMES & SFTS 2014 (2014, September)

Introduction : Des études cliniques ont évalué l’effet du plasma riche en plaquettes (PRP) dans le traitement de la tendinopathie patellaire. Même si une seule infiltration peut améliorer les symptômes du ... [more ▼]

Introduction : Des études cliniques ont évalué l’effet du plasma riche en plaquettes (PRP) dans le traitement de la tendinopathie patellaire. Même si une seule infiltration peut améliorer les symptômes du sportif dans cette indication, la majorité des études évaluent les effets de 3 infiltrations successives. Le but de notre étude était donc de comparer l’efficacité d’une et de 2 infiltrations (rapprochées) de PRP dans le cade de tendinopathies patellaires chroniques, rebelles aux traitements conservateurs. Matériel et méthode : Vingt sportifs souffrant de tendinopathie patellaire depuis plus de 3 mois ont été inclus et randomisés en 2 groupes, respectivement 1 ou 2 infiltrations de PRP (15 jours d’intervalle). Le PRP a été obtenu à l’aide d’une machine d’aphérèse permettant d’obtenir une concentration plaquettaire identique pour tous les sujets. Ils ont bénéficié ensuite d’une rééducation excentrique sous-maximale standardisée. Le suivi a été réalisé à l’aide d’une échelle visuelle analogique de la douleur, de scores algo-fonctionnels (IKDC et VISA-P), ainsi qu’un questionnaire « mode de vie » avant l’infiltration, 3 et 12 mois post-infiltration. Résultats: La concentration de PRP employée était la même au sein des 2 groupes (9x106/µL), et ne contenait pas d’érythrocyte ni de leucocyte. Au terme du suivi (1 an), les résultats montrent une amélioration des scores EVA dans les deux groupes et significative pour le groupe 1 (p=0,005). Les scores VISA-P et IKDC ont tous deux augmentés, significativement dans les deux groupes. Un sujet par groupe n’a pas repris d’activité physique tandis 67% ont repris le sport au niveau antérieur dans le groupe 1 et 78% dans le groupe 2. Conclusion: La comparaison entre 1 et 2 infiltrations rapprochées de PRP n’a pas permis de mettre en évidence de différence entre les 2 groupes sur un suivi d’un an. Une seconde infiltration rapprochée ne semble donc pas indiquée pour améliorer l’efficacité de ce traitement. Cependant, un suivi à plus long terme serait nécessaire. De même l’évaluation d’une seconde infiltration plus à distance (3 mois) de la première mériterait d’être explorée. [less ▲]

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See detailPractical design of a nonlinear tuned vibration absorber
Grappasonni, Chiara ULg; Habib, Giuseppe ULg; Detroux, Thibaut ULg et al

in Proceedings of the ISMA 2014 conference (2014, September)

The aim of the paper is to develop a new nonlinear tuned vibration absorber (NLTVA) capable of mitigating the vibrations of nonlinear systems which are known to exhibit frequency-energy-dependent ... [more ▼]

The aim of the paper is to develop a new nonlinear tuned vibration absorber (NLTVA) capable of mitigating the vibrations of nonlinear systems which are known to exhibit frequency-energy-dependent oscillations. A nonlinear generalization of Den Hartog’s equal-peak method is proposed to ensure equal peaks in the nonlinear frequency response for a large range of forcing amplitudes. An analytical tuning procedure is developed and provides the load-deflection characteristic of the NLTVA. Based on this prescribed relation, the NLTVA design is performed by two different approaches, namely thanks to (i) analytical formulas of uniform cantilever and doubly-clamped beams and (ii) numerical shape optimization of beams with varying width and thickness. A primary system composed of a cantilever beam with a geometrically nonlinear component at its free end serves to illustrate the proposed methodology. [less ▲]

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See detailCIRCULAR TUBE COLUMNS IN HIGH STRENGTH STEEL: Economical solutions for building frames
Hoang, Van Long ULg; Jaspart, Jean-Pierre ULg; Demonceau, Jean-François ULg

in Landolfo, Raffaele; Mazzolani, Frederico (Eds.) Proceeding of the 7th European conference on steel and composite structures (Eurosteel 2014) (2014, September)

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See detailComparaison du VeinoPlus Sport et du TENS sur la récupération de jeunes footballeurs
God, Maxime; LE GOFF, Caroline ULg; Evrard, Frédéric et al

in 7ème Congrès National SFMES & SFTS 2014 (2014, September)

Introduction : Toute activité physique fatigue l’organisme ; les muscles produisent des métabolites et de d’acide lactique, limitant leur fonctionnement. Il est donc nécessaire de pouvoir récupérer de ... [more ▼]

Introduction : Toute activité physique fatigue l’organisme ; les muscles produisent des métabolites et de d’acide lactique, limitant leur fonctionnement. Il est donc nécessaire de pouvoir récupérer de manière efficace au plus vite. En effet, une mauvaise récupération porte préjudice à la performance et à l’état physique du sportif. Aux côtés de la récupération active et de la balnéothérapie de nouvelles techniques comme de la cryothérapie et électrostimulation ont fait leur apparition pour une meilleure récupération. Le but de cette étude était de comparer l’impact de 2 types de stimulateurs : « VeinoPlus Sport » (VPS) et « TENS » sur la récupération des footballeurs amateurs après un effort de type Yo-Yo. Matériel et méthode : Dans un contexte identique, chaque sportif (20 footballeurs; âge moyen = 17,1 ans ± 0,79) a bénéficié du VPS ou du TENS lors de 2 séances différentes après 2 efforts de type Yo-Yo, séparés d’une période de récupération. Quatre prélèvements sanguins (lactate, gaz sanguins, ions, marqueurs cardiaques…) ainsi qu’un évaluation de l’explosivité par Myotest ont été réalisés respectivement avant l’épreuve, juste après, après la récupération et après la seconde épreuve. Un questionnaire relatif à l’état de fatigue a également été rempli par les sujets. Pour l’analyse statistique, nous avons utilisé le logiciel « StatPlus » et réalisé une Anova à mesures répétées ainsi qu’un test de Scheffé. Résultats : Les sportifs ont tous parcouru une plus grande distance lors des 2èmes efforts, surtout au sein du groupe VPS, mais sans différence significative. L’épreuve a déclenché une variation significative de lactatémie, du HCO3- ainsi que de la myoglobine. L’étude des autres paramètres sanguins ainsi que des paramètres de l’explosivité n’a révélé aucune évolution significative tout au long de l’étude. Par contre en ce qui concerne les critères subjectifs (« ressenti »), les footballeurs du groupe VPS ont noté, à 12h et 24h, une moindre douleur aux jambes, une moindre sensation de fatigue, une moindre diminution de la force, une plus grande légèreté ainsi qu’un meilleur état de forme par rapport au groupe TENS. Enfin, en général, et sans noter de préférence particulière pour l’un ou l’autre des appareils, les athlètes ont préféré l’utilisation de l’électrostimulation à leur récupération habituelle. Conclusion : Cette étude ne montre que des différences mineures, non significatives, entre les deux appareils. Les 2 groupes ont parcouru une distance plus grande lors du 2ème effort. Ceci suggère que le test n’était pas épuisant, malgré les signes biologiques de « fatigue ». Cependant, sur des critères subjectifs de récupération et de bien–être, une tendance était en faveur du VPS. Ces résultats seront à prendre en compte pour de nouvelles études avec cette fois des tests plus fatigants. [less ▲]

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See detailAccurate monitoring of the rumination behaviour of cattle using IMU signals from a mobile device
Andriamandroso, Andriamasinoro ULg; Lebeau, Frédéric ULg; Bindelle, Jérôme ULg

in Hopkins, A; Collins, RP; Fraser, MD (Eds.) et al EGF at 50: The Future of European Grasslands. Proceedings of the 25th General Meeting of the European Grassland Federation. (2014, September)

Improving the monitoring of rumination in cattle could help in assessing of the welfare status and their risk of acidosis. In this work, the monitoring of cattle’s behaviour was performed using the ... [more ▼]

Improving the monitoring of rumination in cattle could help in assessing of the welfare status and their risk of acidosis. In this work, the monitoring of cattle’s behaviour was performed using the inertial measurement unit (IMU) present in smartphones mounted on the neck of cows. The processing of both time and frequency domains of the IMU signals was capable to detect accurately the main behaviours (grazing, rumination and other) and highlight the characteristics of the rumination process. The algorithm for analysis of rumination was more accurate for grazing cattle than for silage-fed cattle in stables. [less ▲]

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See detailA rigorous phase separation method for testing nonlinear structures
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Grappasonni, Chiara ULg et al

in Proceedings of ISMA 2014 - International Conference on Noise and Vibration Engineering (2014, September)

The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements ... [more ▼]

The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements collected under broadband forcing. The use of such a type of forcing signal allows to excite multiple NNMs simultaneously and, in turn, to save testing time. A two-step methodology integrating nonlinear system identification and numerical continuation of periodic solutions is proposed for the extraction of the individual NNMs from broadband input and output data. It is demonstrated using a numerical cantilever beam possessing a cubic nonlinearity at its free end. The proposed methodology can be viewed as a nonlinear generalization of the phase separation techniques routinely utilized for experimental modal analysis of linear structures. [less ▲]

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See detailWind Tunnel Experiments On Bridge Stays Cables Protection Tubes In Dry Galloping Conditions: Processing Method For Bi-Stable Phenomenon
Flamand, Olivier; Benidir, Adel; Gaillet, Laurent et al

in Proceedings of the Symposium on the Dynamics and Aerodynamics of Cables - SDAC 2014 (2014, September)

Surface irregularity is one of the parameters that have not been deeply examined on stay cables of cable-stayed bridges. This paper focuses on wind tunnel tests on original High Density Polyethylene cable ... [more ▼]

Surface irregularity is one of the parameters that have not been deeply examined on stay cables of cable-stayed bridges. This paper focuses on wind tunnel tests on original High Density Polyethylene cable covers, in a range of Reynolds numbers from the sub-critical regime to the critical one, corresponding to values ranging from Re = 9.6x104 to Re = 3.3x105. The experiment consists in measurement of parietal pressures on cable covers in order to investigate the effect of surface irregularity on the mechanism of dry galloping excitation. Previous studies ([1], [3] and [4]) reported that dry galloping of cables with a circular cross section is linked to the appearance of a negative pressure bubble, on one side of the circular cylinder at the critical Reynolds number range, leading locally to a rapid drop in the drag coefficient and the appearance of a no negligible lift force. But such a steady change in local lift force does not generate an alternate excitation on a whole cable. The question of the spatial correlation of this “one bubble “ regime along a cable in real conditions and the capability of this lift force to be varied with time are still not resolved. The present paper aims at showing one first exploration of the spatial and temporal correlation of the pressure pattern along the HDPE tube with respect to the natural circularity defect. The Proper Orthogonal Decomposition (POD) was used to characterize the bi-stability phenomenon occurring at critical Reynolds number regime. [less ▲]

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See detailElectronic nose for reactor stability monitoring of an agricultural co-digestion biogas plant
Adam, Gilles ULg; Lemaigre, Sébastien; Delfosse, Philippe et al

in Progress in Biogas III - Biogas Production from agricultural biomass and organic residues (2014, September)

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See detailComparaison du VeinoPlus Sport et du TENS sur la récupération de jeunes footballeurs
God, Maxime; LE GOFF, Caroline ULg; Evrard, Frédéric et al

in 7ème Congrès National SFMES & SFTS 2014 (2014, September)

Introduction : Toute activité physique fatigue l’organisme ; les muscles produisent des métabolites et de d’acide lactique, limitant leur fonctionnement. Il est donc nécessaire de pouvoir récupérer de ... [more ▼]

Introduction : Toute activité physique fatigue l’organisme ; les muscles produisent des métabolites et de d’acide lactique, limitant leur fonctionnement. Il est donc nécessaire de pouvoir récupérer de manière efficace au plus vite. En effet, une mauvaise récupération porte préjudice à la performance et à l’état physique du sportif. Aux côtés de la récupération active et de la balnéothérapie de nouvelles techniques comme de la cryothérapie et électrostimulation ont fait leur apparition pour une meilleure récupération. Le but de cette étude était de comparer l’impact de 2 types de stimulateurs : « VeinoPlus Sport » (VPS) et « TENS » sur la récupération des footballeurs amateurs après un effort de type Yo-Yo. Matériel et méthode : Dans un contexte identique, chaque sportif (20 footballeurs; âge moyen = 17,1 ans ± 0,79) a bénéficié du VPS ou du TENS lors de 2 séances différentes après 2 efforts de type Yo-Yo, séparés d’une période de récupération. Quatre prélèvements sanguins (lactate, gaz sanguins, ions, marqueurs cardiaques…) ainsi qu’un évaluation de l’explosivité par Myotest ont été réalisés respectivement avant l’épreuve, juste après, après la récupération et après la seconde épreuve. Un questionnaire relatif à l’état de fatigue a également été rempli par les sujets. Pour l’analyse statistique, nous avons utilisé le logiciel « StatPlus » et réalisé une Anova à mesures répétées ainsi qu’un test de Scheffé. Résultats : Les sportifs ont tous parcouru une plus grande distance lors des 2èmes efforts, surtout au sein du groupe VPS, mais sans différence significative. L’épreuve a déclenché une variation significative de lactatémie, du HCO3- ainsi que de la myoglobine. L’étude des autres paramètres sanguins ainsi que des paramètres de l’explosivité n’a révélé aucune évolution significative tout au long de l’étude. Par contre en ce qui concerne les critères subjectifs (« ressenti »), les footballeurs du groupe VPS ont noté, à 12h et 24h, une moindre douleur aux jambes, une moindre sensation de fatigue, une moindre diminution de la force, une plus grande légèreté ainsi qu’un meilleur état de forme par rapport au groupe TENS. Enfin, en général, et sans noter de préférence particulière pour l’un ou l’autre des appareils, les athlètes ont préféré l’utilisation de l’électrostimulation à leur récupération habituelle. Conclusion : Cette étude ne montre que des différences mineures, non significatives, entre les deux appareils. Les 2 groupes ont parcouru une distance plus grande lors du 2ème effort. Ceci suggère que le test n’était pas épuisant, malgré les signes biologiques de « fatigue ». Cependant, sur des critères subjectifs de récupération et de bien–être, une tendance était en faveur du VPS. Ces résultats seront à prendre en compte pour de nouvelles études avec cette fois des tests plus fatigants. [less ▲]

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See detailQuantitative and qualitative evaluation of sediment and contaminant transport in the Samme river catchment (Brabant region - Belgium)
Denis, Anne-Cécile ULg; Van Campenhout, Jean ULg; Bouffioux, Anne et al

in Proceedings of 4th International Symposium on Sediment Management (2014, September)

In Wallonia (Belgium), the maintenance of waterways is currently exclusively managed in a curative way. When local sediment accumulations are detected in waterways, bathymetric surveys are conducted in ... [more ▼]

In Wallonia (Belgium), the maintenance of waterways is currently exclusively managed in a curative way. When local sediment accumulations are detected in waterways, bathymetric surveys are conducted in order to quantify the volume of sediment to be removed and chemical analyses of samples allow the characterization of sediment quality. Collected data only allow a short-term management of the matter generated by dredging operations. Medium- or long-term planning of dredging operations is currently not possible, due to a lack of knowledge on sediment fluxes and associated pollutant transport. In particular, issues related to the interactions and mixing of recent and older sediments, or to the input of sediment from unnavigable waterways into larger navigable waterways, are poorly understood. Operational tools allowing the assessment of the effectiveness of preventive measures to be implemented in order to improve the management of sediment in Walloon waterways also have to be developed. This research project aims at contributing to the development of such tools and focuses on the Samme river watershed (Senne catchment – loamy Brabant Region), deemed to be representative of Walloon issues. The Samme river is categorized as an unnavigable waterway. It runs along the old Charleroi-Brussels canal and flows into the new Charleroi-Brussels canal at the foot of the Ronquières inclined plane. The sediments of the bed of the Samme river are characterized by a high concentration of micropollutants (mainly PCB) and contribute to the contamination of a greater volume of sediments in the new Charleroi-Brussels canal, significantly increasing the cost of periodic dredging operations in the canal. The methodology developed is based on (I) an extended monitoring of sediment and pollutant fluxes at the outlet of the catchment and (II) an assessment of within-catchment sediment and pollutant transport. The origin of the Samme riverbed sediments contamination by PCB is poorly understood. Chemical analyses of the sediments of the bed were carried out along the linear course of the Samme river and its main tributary in order to identify the source of pollution. However, numerous connections between the old canal and the Samme river contribute to the transfer of stream sediments and pollutants between both systems and complicate the identification of the source of PCB. At the outlet of the catchment, different methods of river sediment sampling (automatic samplers, turbidity sensors, Time Integrated Samplers) are currently being implemented in order to (I) monitor the amount of suspended matter carried by the Samme river into the Charleroi-Brussels canal, (II) evaluate the associated fluxes of pollutants and (III) evaluate the possibility of setting up a system of retention of the sediments in the Samme catchment. [less ▲]

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See detailReflexive Introduction to the Categorisation of the European Countryside
Schmitz, Serge ULg

in Siljkovic, Zeljka; Cuka, Anita; Pejdo, Ana (Eds.) Contempory development of European rural areas, Book of Abstracts (2014, September)

At the end of the 20th century, French rural geographers used a simple typology that encapsulates three categories of the countryside: Thirty years later, we should probably add new categories ... [more ▼]

At the end of the 20th century, French rural geographers used a simple typology that encapsulates three categories of the countryside: Thirty years later, we should probably add new categories: “agricultural countryside”, “recreational countryside”, “residential countryside”, “greying countryside”, “countryside supplying energy”, “new peasantry countryside”, “Biosphere reserves” and pay attention to other perspectives such as natural and cultural heritage, water resources protection and ecological transition. The paper discusses these old and new types of countryside and underlines main challenges that countryside faces; it shows how sensitive the categorisation could be according to the level of analysis, the period of observation and the perspectives. [less ▲]

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See detailLa place de la communication dans la gestion du risque sous l'angle de la responsabilité sociale: le cas des entreprises seveso
Robert, Jocelyne ULg; Frau, Maité; al

in Boudrandi, Stéphane; Delaye, Richard; Peretti, Jean-Marie (Eds.) L'audit social au service du progrès du management et de la bonne gouvernance-Proceedings (2014, August 29)

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See detailBayesian approach integrating correlated foreign information into a multivariate genetic evaluation
Vandenplas, Jérémie ULg; Gengler, Nicolas ULg

in Book of Abstracts of the 65th Annual Meeting of the European Federation of Animal Science (2014, August 28)

High-perfomance computing facilities proposing shared-memory and distributed-memory multiprocessors are becoming available. With those clusters, parallel computing could lead to increased performances and ... [more ▼]

High-perfomance computing facilities proposing shared-memory and distributed-memory multiprocessors are becoming available. With those clusters, parallel computing could lead to increased performances and problem sizes. However, to our knowledge and especially for variance components estimations, most software available in animal breeding, based on sparse matrices computations, do not allow parallel computing and are limited by memory accessible by the central processing unit, or allow parallel computing only for options with dense matrices computations, which limits anyway problem sizes due to storage of dense matrices. The aim was to propose simple and effective modifications for the BLUPF90 family of programs to reduce computing time with consideration of required memory. Modifications were based on academic free packages proposing solver and sparse inversion for sparse symmetric indefinite linear systems. First, modifications concerned the sparse inversion subroutine implemented in the package FSPAK. Rearrangements of 'do' loops to allow optimizations of computer operations by some compilers and addition of OpenMP directives were performed. The ordering operation was modified to more easily compare a multiple minimum degree algorithm (MMD; implemented in FSPAK) and a multilevel nested dissection algorithm (implemented in METIS 4.0.3). Second, the package PARDISO Version 5.0.0 was used instead of FSPAK. This package proposes in particular a parallel solver and sparse inversion on shared-memory multiprocessors. Modified FSPAK and PARDISO were compared to original FSPAK using MMD through REMLF90. Different models, such as univariate or bivariate (random regressions) test-day animal and single-step genomic models, were tested. All jobs were run 5 times. With an appropriate ordering algorithm, speedup for each REMLF90 iteration were up to 7.5 for modified FSPAK and up to 22.8 for PARDISO with 2 threads. With 4 threads, speedup increased to 8.3 and 32.5, respectively. [less ▲]

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See detailDynamic Simulations of Combined Transmission and Distribution Systems using Parallel Processing Techniques
Aristidou, Petros ULg; Van Cutsem, Thierry ULg

in Proceedings of the 18th PSCC (2014, August 22)

Simulating a power system with both transmission and distribution networks modeled in detail is a huge computational challenge. In this paper, we propose a Schur-complement-based domain decomposition ... [more ▼]

Simulating a power system with both transmission and distribution networks modeled in detail is a huge computational challenge. In this paper, we propose a Schur-complement-based domain decomposition algorithm to provide accurate, detailed dynamic simulations of the combined system. The simulation procedure is accelerated with the use of parallel programming techniques, taking advantage of the parallelization opportunities inherent in domain decomposition algorithms. The proposed algorithm is general, portable and scalable on inexpensive, shared-memory, multicore machines. A large-scale test system is used for its performance evaluation. [less ▲]

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See detailSensitivity based Assessment of Transient Voltage Sags caused by Rotor Swings
Weckesser, Tilman; Jóhansson, Hjörtur; Ostergaard, Jacob et al

in Proc. 18th Power System Computation Conference (2014, August 22)

The paper introduces an approach to investigate voltage sags, which are caused by large generator rotor swings following a transient disturbance. Therefore, the method exploits sensitivities derived from ... [more ▼]

The paper introduces an approach to investigate voltage sags, which are caused by large generator rotor swings following a transient disturbance. Therefore, the method exploits sensitivities derived from the algebraic network equations. These provide information on the impact of a generator on the voltage magnitude at a load bus and the effect of load variation on the generator’s power injection. It is shown that these sensitivities give valuable information to identify critical generator-load pairs and locations for applying preventive control measures. [less ▲]

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See detailX-rays from magnetic massive OB stars
Petit, V.; Cohen, D. H.; Nazé, Yaël ULg et al

in IAU Symposium (2014, August 01)

The magnetic activity of solar-type and low-mass stars is a well known source of coronal X-ray emission. At the other end of the main sequence, X-rays emission is instead associated with the powerful ... [more ▼]

The magnetic activity of solar-type and low-mass stars is a well known source of coronal X-ray emission. At the other end of the main sequence, X-rays emission is instead associated with the powerful, radiatively driven winds of massive stars. Indeed, the intrinsically unstable line-driving mechanism of OB star winds gives rise to shock-heated, soft emission (~0.5 keV) distributed throughout the wind. Recently, the latest generation of spectropolarimetric instrumentation has uncovered a population of massive OB-stars hosting strong, organized magnetic fields. The magnetic characteristics of these stars are similar to the apparently fossil magnetic fields of the chemically peculiar ApBp stars. Magnetic channeling of these OB stars' strong winds leads to the formation of large-scale shock-heated magnetospheres, which can modify UV resonance lines, create complex distributions of cooled Halpha emitting material, and radiate hard (~2-5 keV) X-rays. This presentation summarizes our coordinated observational and modelling efforts to characterize the manifestation of these magnetospheres in the X-ray domain, providing an important contrast between the emission originating in shocks associated with the large-scale fossil fields of massive stars, and the X-rays associated with the activity of complex, dynamo-generated fields in lower-mass stars. [less ▲]

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See detailA quantitative analysis of the effect of flexible loads on reserve markets
Mathieu, Sébastien ULg; Louveaux, Quentin ULg; Ernst, Damien ULg et al

in Proceedings of the 18th Power Systems Computation Conference (PSCC) (2014, August)

We propose and analyze a day-ahead reserve market model that handles bids from flexible loads. This pool market model takes into account the fact that a load modulation in one direction must usually be ... [more ▼]

We propose and analyze a day-ahead reserve market model that handles bids from flexible loads. This pool market model takes into account the fact that a load modulation in one direction must usually be compensated later by a modulation of the same magnitude in the opposite direction. Our analysis takes into account the gaming possibilities of producers and retailers, controlling load flexibility, in the day-ahead energy and reserve markets, and in imbalance settlement. This analysis is carried out by an agent-based approach where, for every round, each actor uses linear programs to maximize its profit according to forecasts of the prices. The procurement of a reserve is assumed to be determined, for each period, as a fixed percentage of the total consumption cleared in the energy market for the same period. The results show that the provision of reserves by flexible loads has a negligible impact on the energy market prices but markedly decreases the cost of reserve procurement. However, as the rate of flexible loads increases, the system operator has to rely more and more on non-contracted reserves, which may cancel out the benefits made in the procurement of reserves. [less ▲]

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See detailWhich agritourism for which suburban countryside? A heuristic and comparative analysis in Wallonia and Grand-Duchy of Luxembourg (part 2)
Dubois, Charline ULg; Schmitz, Serge ULg

in Ianos, Ioan (Ed.) Rural life and rural systems between tradition and integrated urban-rural development (2014, August)

Mutations, transformations, transitions are keywords which open the door to many questions regarding the global European agriculture. The resources of the rural countryside in Europe are subject to many ... [more ▼]

Mutations, transformations, transitions are keywords which open the door to many questions regarding the global European agriculture. The resources of the rural countryside in Europe are subject to many pressures. Agricultural activities are decreasing and farmers are losing importance. In some northwestern European countryside, the declining agriculture compels to diversify activities in farms. Some farmers need to rethink their business goals in order to successfully sustain their operations in the economic space. In many areas, one of the solutions suggested is the development of agritourism. Agritourism in Wallonia and in the Grand-Duchy of Luxembourg is a tourist activity proposed by the farmer in his farm. While addressing the challenges and countering threats of their agriculture, both suburban areas present many advantages and opportunities for tourism development. Different tourist and leisure developments are conceived and proposed. The activity is reinforced by popular images of sustainability and ecology. Is agritourism a universal solution or is it a reflected contextualized solution? In the Tel-Aviv CSRS meeting, in 2010, we presented a communication on this issue. While the theoretical review and the aim of the first paper were well presented, the empirical results were not well documented because we were at the beginning of the PhD research. Today, we propose, in this paper, to improve information and to answer to the different comments from the members of the commission. Agritourism should be defined, localized, differentiated. Between 2010 and 2014, we conducted interviews of Walloon and Luxembourg tenants (n = 33), surveys among potential tourists (n = 1148) in seven tourist places, interviews of privileged witnesses (n = 31), and field observations. Working on two regions of Western Europe which had not been analyzed previously, the Walloon and Luxembourg suburban countryside, we want to understand the agritourism dynamics, the factors that influence the location and development, and the images of farm tourism. The purpose of this research is to understand the geographical relationship between agritourism, countryside, local resources, agriculture, and tourism specialization. This issue is underdeveloped in the literature and our PhD thesis contributes to fill this gap. We scrutinize the spatial distribution of agritourism in both regions, the logic of emergence of tourism in a farm, the links between these tourist functions and these agricultural functions. We analysed the tenants and visitors’ reasons and motivations in regards of the regional and local context. Finally, we build a typology of the countryside according to agritourism. We conclude that the farm diversification should pay attention to several local and regional factors to succeed in a win-win combination of tourism and agriculture. These factors are listed in a heuristic model, which is a user-friendly tool to think future development of agritourism in the European countryside. [less ▲]

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See detailMise en réseau des acteurs, des activités et des produits touristiques dans les chefferies de l’Ouest -Cameroun
Lekane Tsobgou, Dieudonné ULg; Schmitz, Serge ULg

in Bokwa, Anita (Ed.) Changes, Challenges, Responsability. IGU 2014 Book of Abstracts (2014, August)

Cette recherche propose comme défis a relever, d’élaborer des dispositifs, des outils et la méthodologie de mise en réseau dans le secteur du tourisme dans les Chefferies de l'Ouest du Cameroun. La ... [more ▼]

Cette recherche propose comme défis a relever, d’élaborer des dispositifs, des outils et la méthodologie de mise en réseau dans le secteur du tourisme dans les Chefferies de l'Ouest du Cameroun. La communication discute des logiques (construit processuel) de la mise en réseau d’acteurs, d’activités et de ressources territoriales dans un circuit touristique [less ▲]

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See detailInnovative lactation stage specific prediction of CH4 from milk MIR spectra
Vanlierde, Amélie; Vanrobays, Marie-Laure ULg; Dehareng, Frédéric et al

in Book of abstracts of the 65th annual meeting of the European Federation of Animal Science (2014, August)

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See detailThe quest for rurality in Wallonia in 2013 (Belgium)
Schmitz, Serge ULg

in Bokwa, Anita (Ed.) Changes, Challenges Responsability. IGU 2014 Book of Abstarcts. (2014, August)

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See detailInsulin Sensitivity Variability during Hypothermia
Sah Pri, Azurahisham; Chase, J. Geoffrey; Pretty, Christopher et al

in Proceedings of the 19th IFAC Conference (2014, August)

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See detailAdvanced optimization methods for power systems
Panciatici, Patrick; Campi, M.C.; Garatti, S. et al

in Proceedings of the 18th Power Systems Computation Conference (2014, August)

Power system planning and operation offers multitudinous opportunities for optimization methods. In practice, these problems are generally large-scale, non-linear, subject to uncertainties, and combine ... [more ▼]

Power system planning and operation offers multitudinous opportunities for optimization methods. In practice, these problems are generally large-scale, non-linear, subject to uncertainties, and combine both continuous and discrete variables. In the recent years, a number of complementary theoretical advances in addressing such problems have been obtained in the field of applied mathematics. The paper introduces a selection of these advances in the fields of non-convex optimization, in mixedinteger programming, and in optimization under uncertainty. The practical relevance of these developments for power systems planning and operation are discussed, and the opportunities for combining them, together with high-performance computing and big data infrastructures, as well as novel machine learning and randomized algorithms, are highlighted. [less ▲]

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See detailRelaxations for multi-period optimal power flow problems with discrete decision variables
Gemine, Quentin ULg; Ernst, Damien ULg; Louveaux, Quentin ULg et al

in Proceedings of the 18th Power Systems Computation Conference (PSCC'14) (2014, August)

We consider a class of optimal power flow (OPF) applications where some loads offer a modulation service in exchange for an activation fee. These applications can be modeled as multi-period formulations ... [more ▼]

We consider a class of optimal power flow (OPF) applications where some loads offer a modulation service in exchange for an activation fee. These applications can be modeled as multi-period formulations of the OPF with discrete variables that define mixed-integer non-convex mathematical programs. We propose two types of relaxations to tackle these problems. One is based on a Lagrangian relaxation and the other is based on a network flow relaxation. Both relaxations are tested on several benchmarks and, although they provide a comparable dual bound, it appears that the constraints in the solutions derived from the network flow relaxation are significantly less violated. [less ▲]

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See detailAn AC OPF-based Heuristic Algorithm for Optimal Transmission Switching
Capitanescu, Florin; Wehenkel, Louis ULg

in Proceedings of the 18th Power Systems Computation Conference (2014, August)

This paper focuses on reducing generators dispatch cost by means of transmission line switching. The problem is formulated as a mixed-integer nonlinear program (MINLP) optimal power flow (OPF). A scalable ... [more ▼]

This paper focuses on reducing generators dispatch cost by means of transmission line switching. The problem is formulated as a mixed-integer nonlinear program (MINLP) optimal power flow (OPF). A scalable heuristic algorithm is proposed to break-down the complexity of the problem due to the huge combinatorial space. The algorithm aims at providing the sequence of lines to be removed from service, one at the time, until no further decrease in the dispatch cost can be obtained. It identifies the line candidate for removal at each step by exploiting the (continuously relaxed values of) lines breaker statuses at the solution of a relaxed OPF problem. The algorithm thus relies on solving a sequence of OPF problems formulated as nonlinear programs (NLPs). The effectiveness of the approach is demonstrated on the IEEE118-bus system. Results show that the approach can provide good quality sub-optimal solutions with relatively small computational effort and by removing only few lines from service. [less ▲]

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See detailModel-Based Computation of Total Stressed Blood Volume from a Preload Reduction Experiment
Pironet, Antoine ULg; Desaive, Thomas ULg; Chase, J. Geofrrey et al

in Preprints of the 19th World Congress (2014, August)

Total stressed blood volume is an important parameter for both doctors and engineers. From a medical point of view, it has been associated with the success or failure of fluid resuscitation therapy, which ... [more ▼]

Total stressed blood volume is an important parameter for both doctors and engineers. From a medical point of view, it has been associated with the success or failure of fluid resuscitation therapy, which is a treatment for cardiac failure. From an engineering point of view, this parameter dictates the cardiovascular system’s dynamic behavior. Current methods to determine this parameter involve repeated phases of circulatory arrests followed by fluid administration. In this work, a method is developed to compute stressed blood volume from preload reduction experiments. A simple six-chamber cardiovascular system model is used and its parameters are adjusted to pig experimental data. The parameter adjustment process has three steps: (1) compute nominal values for all model parameters; (2) determine the most sensitive parameters; and (3) adjust only these sensitive parameters. Stressed blood volume was determined sensitive for all datasets, which emphasizes the importance of this parameter. The model was able to track experimental trends with a maximal mean squared error of 11.77 %. Stressed blood volume has been computed to range between 450 and 963 ml, or 15 to 28 ml/kg, which matches previous independent experiments on pigs, dogs and humans. Consequently, the method proposed in this work provides a simple way to compute total stressed blood volume from usual hemodynamic data. [less ▲]

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See detailNumerical Investigation of Cooling in the Continuous Fiber Glass Drawing Process
Chouffart, Quentin ULg; Terrapon, Vincent ULg; Simon, Philippe

in Proceedings of the 15th International Heat Transfer Conference (2014, August)

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through an array of thousands of small orifices (i.e., the ... [more ▼]

The manufacturing process of glass fibers used for the reinforcement of composite material consists in drawing a glass melt at high temperature through an array of thousands of small orifices (i.e., the bushing plate) into fibers using a winder. This process is sensitive to numerous disturbances that can cause a fiber to break during the drawing process. This paper analyzes how the stress in the fiber depends on the controlling parameters of the process. The approach relies on numerical simulations and sensitivity analysis. Both a semi-analytical one-dimensional model and a more complex two-dimensional axisymmetric model are used. It is first found that radial variations across the fiber are small compared to changes in the axial direction and that the one-dimensional approximation is accurate enough to describe the major trends in the process. Sensitivity analyses on some physical parameters controlling the heat transfers and on process parameters are then performed to identify strategies to reduce the axial stress. In particular, it is shown that, for a given fiber diameter, the stress is minimized if the glass melt temperature and the drawing velocity are increased. This approach is then applied to quantify the effect of inhomogeneous heat patterns on a bushing plate with a large number of fibers. [less ▲]

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See detailImprovement of defect detection in shearography by using Principal Component Analysis
Vandenrijt, Jean-François ULg; Lièvre, Nicolas; Georges, Marc ULg

in Proceedings of Conference on Interferometry XVII: Techniques and Analysis (2014, August)

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See detailPrediction of Body Weight of Primiparous Dairy Cows Throughout Lactation
Vanrobays, Marie-Laure ULg; Vandenplas, Jérémie ULg; Hammami, Hedi ULg et al

in Proceedings of the 10th World Congress on Genetics Applied to Livestock Production (2014, August)

Body weight (BW) can be computed using linear conformation traits (CBW). However, these traits are recorded mostly once during a lactation. Therefore, predicted BW (PBW) is needed throughout the lactation ... [more ▼]

Body weight (BW) can be computed using linear conformation traits (CBW). However, these traits are recorded mostly once during a lactation. Therefore, predicted BW (PBW) is needed throughout the lactation (e.g., allowing feed intake prediction in milk recording systems). A two-step procedure was developed to obtain PBW using a random regression test-day model using CBW as observations. Added second step consisted in changing prior distribution for additive genetic random effects using results from first step to predict again PBW. This method was applied on 24,919 primiparous Holstein cows having 25,061 CBW to obtain PBW for 232,436 test-days. Results showed that applying both steps provided more accurate estimates than using only the first step. Furthermore, this procedure predicting PBW throughout lactation is also extremely flexible because actual BW can also be used together with CBW, the prediction model being able to accommodate different levels of accuracies. [less ▲]

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See detailCombining magnetic and seismic studies to constrain processes in massive stars
Neiner, C.; Degroote, P.; Coste, B. et al

in IAUS 302 - Magnetic Fields Throughout Stellar Evolution (2014, August)

The presence of pulsations influences the local parameters at the surface of massive stars and thus it modifies the Zeeman magnetic signatures. Therefore it makes the characterisation of a magnetic field ... [more ▼]

The presence of pulsations influences the local parameters at the surface of massive stars and thus it modifies the Zeeman magnetic signatures. Therefore it makes the characterisation of a magnetic field in pulsating stars more difficult and the characterisation of pulsations is thus required for the study of magnetic massive stars. Conversely, the presence of a magnetic field can inhibit differential rotation and mixing in massive stars and thus provides important constraints for seismic modelling based on pulsation studies. As a consequence, it is necessary to combine spectropolarimetric and seismic studies for all massive classical pulsators. Below we show examples of such combined studies and the interplay between physical processes. [less ▲]

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See detailSurvey about diffusion and adoption of glycaemic controller in European intensive care units
Penning, Sophie ULg; Pironet, Antoine ULg; Chase, J. Geoffrey et al

in Proceedings of the 19th IFAC Conference (2014, August)

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See detailImproving dairy cow fertility using milk-based indicator traits
Bastin, Catherine ULg; Vandenplas, Jérémie ULg; Gengler, Nicolas ULg

in Proceedings of the 10th World Congress on Genetics Applied to Livestock Production (2014, August)

Improvement of dairy cow fertility by means of genetic selection has become increasingly important over the last decades. Because fertility traits are difficult to measure and have low heritabilities ... [more ▼]

Improvement of dairy cow fertility by means of genetic selection has become increasingly important over the last decades. Because fertility traits are difficult to measure and have low heritabilities, indicator traits are of interest to supplement the prediction of genetic merit for female fertility. This paper examines milk-based traits that could be potential predictor of fertility: changes in protein and fat composition, fat to protein ratio, urea, lactose, ketone bodies, and mid-infrared prediction of body energy traits. The pattern of genetic correlations between these traits and fertility over days in milk is likely related to the cow’s energy balance state. Furthermore, changes in milk fatty acid profile were demonstrated as good potential predictors of fertility. Finally, additional research is warranted to investigate the association over the lactation between fertility and changes in milk biomarkers, potentially predicted by mid-infrared analysis of milk. [less ▲]

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See detailAssessment of pulmonary hypertension in dogs with chronic pulmonary diseases by thoracic ct-angiography.
Couvreur, T.; Roels, Elodie ULg; Merveille, Anne-Christine ULg et al

in Proceedings of the ECVDI Meeting, Utrecht - Netherlands - 27-30 August 2014 (2014, August)

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See detailCreation of universal MIR calibration by standardization of milk spectra: example of fatty acids
Grelet, Clément; Fernandez Pierna, Juan; Soyeurt, Hélène ULg et al

in Book of abstracts of the 65th annual meeting of the European Federation of Animal Science (2014, August)

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See detailEnhancement of ray tracing method for radiative heat transfer: application to EUI space instrument
Jacques, Lionel ULg; Masset, Luc ULg; Kerschen, Gaëtan ULg

in Proceedings of the 15th International Heat Transfer Conference, IHTC-15 (2014, August)

The finite element method (FEM) is widely used in mechanical engineering, in particular for space structure design. However, FEM is not yet often used for thermal engineering of space structures where the ... [more ▼]

The finite element method (FEM) is widely used in mechanical engineering, in particular for space structure design. However, FEM is not yet often used for thermal engineering of space structures where the lumped parameter method is still dominant. Radiative exchange factors (REFs), used to calculate radiative thermal exchanges in space, are usually computed through Monte Carlo ray tracing. Due to the large number of elements composing a FE model, the computation of the REFs is prohibitively expensive. The isocell method aims at reducing the computational effort of the REFs with FEM, by decreasing the number of rays required to achieve a given accuracy. Based on Nusselt’s analogy, the ray direction sampling is carried out by sampling the unit disc to derive the ray directions. The isocell method is a special case of stratified sampling. It divides the unit disc into cells of almost same area and shape from which random points are generated. This enhances the uniformity of the ray directions and leads to faster convergence. This isocell method is associated with different surface sampling to derive the REFs. The method is benchmarked against ESARAD, the standard thermal analysis ray tracing engine used in the European aerospace industry. One entrance baffle of the Extreme Ultraviolet Imager (EUI) instrument developedat the Centre Spatial de Liège in Belgium is used as benchmarking case. Solar Orbiter is an European Space Agency mission to be launched in a Sun-centered 0.28 perihelion orbit. [less ▲]

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See detailStructural Identifiability Analysis of a Cardiovascular System Model
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

in Preprints of the 19th World Congress (2014, August)

A simple experimentally validated cardiovascular system model has been shown to be able to track the evolution of various diseases. The model has previously been made patient-specific by adjustment of its ... [more ▼]

A simple experimentally validated cardiovascular system model has been shown to be able to track the evolution of various diseases. The model has previously been made patient-specific by adjustment of its parameters on the basis of a minimal set of hemodynamic measurements. However, this model has not yet been shown to be structurally identifiable, which means that the adjusted model parameters may not be unique. The model equations were manipulated to show that, from a theoretical point of view, all of their parameters can be exactly retrieved from a restricted set of model outputs. However, this set of model outputs is still too large for a clinical application, because it includes left and right ventricular pressures. Consequently, further hypotheses that determine some model parameter values have to be made for the model to be clinically applicable. [less ▲]

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See detailA relaxation scheme to combine Phasor-Mode and Electromagnetic Transients Simulations
Plumier, Frédéric ULg; Aristidou, Petros ULg; Geuzaine, Christophe ULg et al

in Proceedings of the 18th Power System Computation Conference (2014, August)

This paper deals with a new scheme for coupling phasor-mode and electromagnetic transients simulations. In each simulation, an iteratively updated linear equivalent is used to represent the effect of the ... [more ▼]

This paper deals with a new scheme for coupling phasor-mode and electromagnetic transients simulations. In each simulation, an iteratively updated linear equivalent is used to represent the effect of the subsystem treated by the other simulation. Time interpolation and phasor extraction methods adapted to this scheme are presented and compared to existing methods. Finally, simulation results obtained with a 74-bus test system are reported. [less ▲]

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See detailUsing milk spectral data for large-scale phenotypes linked to mitigation and efficiency
Soyeurt, Hélène ULg; Vanlierde, Amélie; Vanrobays, Marie-Laure ULg et al

in Book of abstracts of the 65th annual meeting of the European Federation of Animal Science (2014, August)

Even if producing milk efficiently has always been a major concern for producers, the direct environmental impact of their cows is becoming a novel one. Traits linked to this issue were identified as ... [more ▼]

Even if producing milk efficiently has always been a major concern for producers, the direct environmental impact of their cows is becoming a novel one. Traits linked to this issue were identified as methane emission (CH4), dry matter intake (DMI) and feed efficiency (FE); however they are available on a small scale. Researches showed that CH4 could be predicted from milk mid-infrared (MIR) spectra, allowing large-scale recording at low cost. The main objective of this study was to show, using a modelling approach, that DMI and FE could be derived from milk MIR spectra. For that, knowledge of body weight (BW) is required; however it was unknown in this study. Derived procedure was based on milk yield and composition, MIR CH4, and modelled standard animal requirements, allowing the prediction of expected BW. An external validation was conducted based on 91 actual records. 95% confidence limit for the difference ranged between -0.66 and 18.84 kg for BW, from -0.02 to 0.26 kg/day for DMI, and from -0.02 to 0.002 kg of fat corrected milk/kg DM for FE. Root mean square errors were 39.66 kg, 0.56 kg/d, and 0.03 kg/DM for the 3 studied traits. P-value for the t-test was not significant for BW and DMI. This suggests the possibility to obtain expected BW and therefore DMI from MIR spectra. Single trait animal test-day models used 1,291,850 records to assess the variability of studied traits. Significant variations were observed for the lactation stage, parity, genetics, and age. These findings were in agreement with the literature except for early lactation. This suggests in conclusion that the MIR information gave similar results for DMI and CH4 for the major part of lactation. The use of this novel method to predict expected BW offers new possibilities interesting for the development of genomic and genetic tools. [less ▲]

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See detailDetection of wheat root and straw in soil by use of NIR hyperspectral imaging spectroscopy and Partial Least Square discriminant analysis
Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio; Baeten, Vincent et al

in Szilvássy, Zoltán; Pepó, Péter; Csajbók, József (Eds.) Book of Abstracts, ESA XIIIth Congress : ESA, Debrecen 25-29 August 2014 (2014, August)

Monitoring of root systems development and crop residues decomposition is only possible if these constituents can be discriminated from soil and quantified. In this work, Near Infrared (NIR) combined with ... [more ▼]

Monitoring of root systems development and crop residues decomposition is only possible if these constituents can be discriminated from soil and quantified. In this work, Near Infrared (NIR) combined with Hyperspectral Imaging (HSI) and Partial Least Square Discriminant Analysis (PLS-DA) is proposed as a new rapid and reliable method to discriminate soil, roots and straws. NIR-HSI provides simultaneously spectral and spatial information and PLS-DA allows discrimination between classes based on spectra of each pixel linked to chemical nature of sample constituents on the image. [less ▲]

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See detailAlgorithmic and Computational Advances for Fast Power System Dynamic Simulations
Aristidou, Petros ULg; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES General Meeting (2014, July 30)

In this paper, some algorithmic and computational advances are presented for power system dynamic simulations. The heart is a Schur-complement-based solution algorithm, stemming from domain decomposition ... [more ▼]

In this paper, some algorithmic and computational advances are presented for power system dynamic simulations. The heart is a Schur-complement-based solution algorithm, stemming from domain decomposition methods, applied to the differential-algebraic equation model. This algorithm is then accelerated computationally, by employing parallel computing techniques, and numerically, by exploiting time-scale decomposition and localization. Models of a real medium-scale system and a realistic large-scale test system are used for the performance evaluation of the proposed methods. [less ▲]

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See detailRécits de vie d’adolescents. Humeur dépressive et figures parentales
Poudat, Céline; Boulard, Aurore ULg

in 4ème Congrès Mondial de Linguistique Française (2014, July 22)

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See detailThe VORTEX project: first results and perspectives
Absil, Olivier ULg; Mawet, Dimitri; Delacroix, Christian ULg et al

in Marchetti, Enrico; Close, Laird; Véran, Jean-Pierre (Eds.) Adaptive Optics Systems IV (2014, July 21)

Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They feature a very small inner working angle (down to the ... [more ▼]

Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They feature a very small inner working angle (down to the diffraction limit of the telescope), a clear 360 degree discovery space, have demonstrated very high contrast capabilities, are easy to implement on high-contrast imaging instruments, and have already been extensively tested on the sky. Since 2005, we have been designing, developing and testing an implementation of the charge-2 vector vortex phase mask based on concentric sub-wavelength gratings, referred to as the Annular Groove Phase Mask (AGPM). Science-grade mid-infrared AGPMs were produced in 2012 for the first time, using plasma etching on synthetic diamond substrates. They have been validated on a coronagraphic test bench, showing broadband peak rejection up to 500:1 in the L band, which translates into a raw contrast of about 6e-5 at 2λ/D. Three of them have now been installed on world-leading diffraction-limited infrared cameras, namely VLT/NACO, VLT/VISIR and LBT/LMIRCam. During the science verification observations with our L-band AGPM on NACO, we observed the beta Pictoris system and obtained unprecedented sensitivity limits to planetary companions down to the diffraction limit (0.1"). More recently, we obtained new images of the HR 8799 system at L band during the AGPM first light on LMIRCam. After reviewing these first results obtained with mid-infrared AGPMs, we will discuss the short- and mid-term goals of the on-going VORTEX project, which aims to improve the performance of our vortex phase masks for future applications on second-generation high-contrast imager and on future extremely large telescopes (ELTs). In particular, we will briefly describe our current efforts to improve the manufacturing of mid-infrared AGPMs, to push their operation to shorter wavelengths, and to provide deeper starlight extinction by creating new designs for higher topological charge vortices. Within the VORTEX project, we also plan to develop new image processing techniques tailored to coronagraphic images, and to study some pre- and post-coronagraphic concepts adapted to the vortex coronagraph in order to reduce scattered starlight in the final images. [less ▲]

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See detailApplication of multiple-point geostatistics on groundwater flow and transport in media with complex geological heterogeneity: lessons learnt and remaining challenges
Huysmans, Marijke; Dassargues, Alain ULg

in Proceedings (2014, July 09)

Multiple-point geostatistics has been increasingly applied on groundwater problems in the last ten years. Several case studies have been published indicating simulating realistic geological heterogeneity ... [more ▼]

Multiple-point geostatistics has been increasingly applied on groundwater problems in the last ten years. Several case studies have been published indicating simulating realistic geological heterogeneity using multiple-point geostatistics can significantly improve groundwater flow and solute transport predictions. There are however several remaining challenges when applying multiple-point geostatistics to groundwater problems often suffering from data scarcity. These challenges might be the reason why multiple-point has been used to a much lesser extent by practitioners than by researchers. This paper gives an overview of the current challenges and discusses new advancements to overcome them. The following questions will be discussed: How to obtain 3D training images? Can the representativity of the used training image be validated ? How sensitive are groundwater calculations to the selection of the training image? Is it worth incorporating fine scale geological heterogeneity in groundwater problems or are other features (boundary conditions, data uncertainty/quality, …) more important for improving predictions? How can multiple-point geostatistics be used without suffering from very long computation times for the numerical models? Is overparametrization of groundwater models an issue ? What are the practical obstacles to apply multiple-point geostatistics by groundwater practitioners? [less ▲]

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See detailMICROPHYSIQUE DES NUAGES ET RAYONNEMENT SOLAIRE : COMPARAISON DES MESURES IN SITU AU MONT RIGI EN HAUTE BELGIQUE ET DES DONNÉES CLOUD PHYSICAL PROPERTIES (CPP) OBTENUES À PARTIR DES IMAGES METEOSAT-9
Beaumet, Julien ULg; Clerbaux, Nicolas; Cornet, Yves ULg et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du XXVIIe Colloque de l'Association Internationale de Climatologie : CLIMAT : SYSTÈME & INTERACTIONS (2014, July 02)

Le rayonnement solaire global mesuré au mont Rigi a été comparé à l'épaisseur optique des nuages (COT) estimée à l'aide des données SEVIRI. Une relation logarithmique avec un coefficient de détermination ... [more ▼]

Le rayonnement solaire global mesuré au mont Rigi a été comparé à l'épaisseur optique des nuages (COT) estimée à l'aide des données SEVIRI. Une relation logarithmique avec un coefficient de détermination d'environ 0,5 a été trouvée. Ce résultat plutôt faible peut en grande partie s'expliquer par un nombre limité de cas où subsistent des erreurs de positionnement ou par des interactions plus complexes entre nébulosité et rayonnement. De plus, l'incertitude sur l'estimation de l'épaisseur optique des nuages à l'aide des données SEVIRI pour les nuages optiquement plus épais n'est pas négligeable. [less ▲]

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See detailComparaison entre le profil vertical de la vitesse du vent observé dans les basses couches de la troposphère et celui simulé par le modèle WRF en Belgique
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Beaumet, Julien ULg et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du XXVIIe Colloque de l'Association Internationale de Climatologie : CLIMAT : SYSTÈME & INTERACTIONS (2014, July 02)

In the framework of FLEXIPAC project funded by the "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust ... [more ▼]

In the framework of FLEXIPAC project funded by the "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust the WRF regional model (v.3.4.) forced by the ERA-Interim reanalysis for Belgium. Our analysis shows that wind speeds at 100m simulated by WRF are systematically overestimated compared to wind speeds extracted from wind productions of two wind farms. In order to solve this problem, four ways are considered in this contribution. The first way is to compare the WRF model with the reanalysis data. The second way is to test the influence of the spatial resolution by running WRF with a finer resolution. The third way is to smooth WRF outputs, where in order to analyze the variability created by the model. And finally, the fourth way is to compare the WRF model with the MAR (v3.3.) regional model. This last way seems to confirm that the MAR model better simulates wind speeds at 10m and at 100m than the WRF model. [less ▲]

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See detailThe X-ray Integral Field Unit (X-IFU) for Athena
Ravera, Laurent; Barret, Didier; den Herder, Jan Willem et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2014, July 01)

Athena is designed to implement the Hot and Energetic Universe science theme selected by the European Space Agency for the second large mission of its Cosmic Vision program. The Athena science payload ... [more ▼]

Athena is designed to implement the Hot and Energetic Universe science theme selected by the European Space Agency for the second large mission of its Cosmic Vision program. The Athena science payload consists of a large aperture high angular resolution X-ray optics (2 m2 at 1 keV) and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager. The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), offering 2:5 eV spectral resolution, with ~5" pixels, over a field of view of 50 in diameter. In this paper, we present the X-IFU detector and readout electronics principles, some elements of the current design for the focal plane assembly and the cooling chain. We describe the current performance estimates, in terms of spectral resolution, effective area, particle background rejection and count rate capability. Finally, we emphasize on the technology developments necessary to meet the demanding requirements of the X-IFU, both for the sensor, readout electronics and cooling chain. [less ▲]

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See detailEarly Prediction of Transient Voltage Sags caused by Rotor Swings
Weckesser, Tilman; Johannsson, Hjortur; Van Cutsem, Thierry ULg

in Proc. IEEE PES general meeting (2014, July)

The paper investigates various methods to predict voltage sags at load buses caused by large generator rotor swings and following a transient disturbance. Three different prediction methods are proposed ... [more ▼]

The paper investigates various methods to predict voltage sags at load buses caused by large generator rotor swings and following a transient disturbance. Three different prediction methods are proposed, which all use real-time measurements from PMUs. One of the methods uses a slightly extended version of the E-SIME method. The other two methods use measurements and process them by recursive least square estimation. It is shown that the prediction method employing E-SIME allows the earliest detection of a critical voltage sag with satisfactory accuracy. [less ▲]

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See detailComputation of damped nonlinear normal modes with internal resonances: a boundary value approach
Renson, Ludovic ULg; Touzé, Cyril; Kerschen, Gaëtan ULg

in Proceedings of the 8th European Nonlinear Dynamics Conference (ENOC 2014) (2014, July)

This paper considers the computation of nonlinear normal modes (NNMs) defined as two-dimensional manifolds in phase space. Because existing methods use explicit manifold parameterization, NNM computation ... [more ▼]

This paper considers the computation of nonlinear normal modes (NNMs) defined as two-dimensional manifolds in phase space. Because existing methods use explicit manifold parameterization, NNM computation in the presence of internal resonances requires multiple pairs of constraint coordinates. This paper investigates an alternative method for which the manifold is computed using successive boundary value problems. [less ▲]

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See detailSmart Grid Energy Flexible Buildings through the use of Heat Pumps in the Belgian context
Georges, Emeline ULg; Masy, Gabrielle; Verhelst, Clara et al

in 3rd International High Performance Buildings Conference at Purdue (2014, July)

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See detailOptimization Of A Heat Pump For Satellite Cooling
Bell, Ian ULg; Lemort, Vincent

in 15 th International Refrigeration and Air Conditioning Conference at Purdue (2014, July)

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See detailAdvanced Aeroservoelastic Modeling for Horizontal axis Wind Turbines
Prasad, Chandra Shekhar ULg; Chen, Qiong-zhong; Dimitriadis, Grigorios ULg et al

in Cunha, A.; Caetano, E.; Riberio, P. (Eds.) et al Proceedings of the 9th International Conference on Structural Dynamics, EURODYN 2014 (2014, July)

This paper describes the development of a complete methodology for the unsteady aeroelastic and aeroservoelastic modeling of horizontal axis wind turbines at the design stage. The methodology is based on ... [more ▼]

This paper describes the development of a complete methodology for the unsteady aeroelastic and aeroservoelastic modeling of horizontal axis wind turbines at the design stage. The methodology is based on the implementation of unsteady aerodynamic modeling, advanced control strategies and nonlinear finite element calculations in the S4WT wind turbine design package. The aerodynamic modeling is carried out by means of the unsteady Vortex Lattice Method, including a free wake model. The complete model also includes a description of a doubly fed induction generator and its control system for variable speed operation and enhanced power output. The S4WT software features a non-linear finite element solver with multi-body dynamics capability. The complete methodology is used to perform complete aeroservoelastic simulations of a 2MW wind turbine prototype model. The interaction between the three components of the approach is carefully analyzed and presented here. [less ▲]

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See detailModeling the hygrothermal response of a prefabricated straw bale panel and assessing its impact on indoor climate
Dubois, Samuel ULg; Evrard, Arnaud; Lebeau, Frédéric ULg

in 2014 ASABE and CSBE/SCGAB Annual International Meeting (2014, July)

Crop-based materials show many qualities in the quest for construction products with low environmental impact in the construction sector. Their ability to exchange moisture with indoor air offers new ... [more ▼]

Crop-based materials show many qualities in the quest for construction products with low environmental impact in the construction sector. Their ability to exchange moisture with indoor air offers new opportunities for improving interior user comfort and eventually buildings energy performance. Modeling their hygrothermal behavior has thus focused much attention, one of the main objectives being to assess more objectively the resulting performance at building scale. The first natural step in this modeling process is to understand the specific dynamics of heat and mass transfer within such materials. The Building Element Heat Air and Moisture (BEHAM) numerical models were designed to accurately predict internal conditions encountered in materials with partial balance equations. This envelope-based approach, however, requires the knowing of the interior and exterior climate conditions prior to the study. Therefore, it forbids any assessment of mutual exchange between the envelope to the indoor air and prevents any serious validation of the overall performance of materials. In response to this problem, the importance of developing whole building hygrothermal model has recently been raised. General scientific computational tools like MATLAB seem particularly adapted to perform this scaling-up, given their high flexibility and tools integration potentialities. In this communication we study a prefabricated straw bale panel subjected to two distinct and simple solicitations in a climatic chamber. A whole building hygrothermal model developed in MATLAB is then validated with the experimental datasets. The evolution of indoor conditions under the different tests is analyzed in details with an assessment of straw bales performance. [less ▲]

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See detailWhen children stop trusting what they have perceived
Geurten, Marie ULg; Willems, Sylvie; Meulemans, Thierry ULg

in Neuropsychological Rehabilitation Special Interest Group of the WFNR - Conference Programme (2014, July)

Background and aims: A common hypothesis to explain metamemory heuristics learning throughout childhood lies on the assumption that the knowledge underlying these metacognitive rules develop from people’s ... [more ▼]

Background and aims: A common hypothesis to explain metamemory heuristics learning throughout childhood lies on the assumption that the knowledge underlying these metacognitive rules develop from people’s prior day-to-day experiences. However, the specific processes that sustain this learning are still unclear. In this study, we examined the mechanisms implicated in this empirical development by manipulating the learned interpretation of the Easily Learned = Easily Remembered (ELER) heuristic through an implicit process involving the detection of environmental regularities. Method: A sample of sixty normally developing children aged 4-5, 6-7, and 8-9 years old was recruited for this study. Each child participated in three 60-minute sessions separated approximately by one-week interval and was trained to learn implicitly a reverse interpretation of the ELER heuristic. The influence of executive functions on children’s judgment of learning at posttest was also investigated. Results: In addition to an early development of the ELER heuristic, results revealed a reduction of this heuristic’s use after the implicit training in the two youngest groups. Furthermore, executive monitoring was demonstrated to account for the lack of change observed in older children after the training phases. Conclusions: In a developmental perspective, these findings present a coherent picture of children’s learning of metacognitive heuristics. Specifically, automatic and implicit learning was demonstrated to be followed by an effortful control of the heuristics’ use. [less ▲]

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See detailRisk assessment of soil compaction in Walloon Region
D'Or, Dimitri; Destain, Marie-France ULg

in Proceedings of geoENV2014 (2014, July)

It is well established that soil compaction affects the growth and functioning of roots and disrupts the activity of microfauna and soil microorganisms, resulting in a loss of yields. Agriculture and ... [more ▼]

It is well established that soil compaction affects the growth and functioning of roots and disrupts the activity of microfauna and soil microorganisms, resulting in a loss of yields. Agriculture and forestry using increasingly heavy machines, the risk of soil compaction is increasing accordingly. Chosen as indicator of the susceptibility of soils to compaction, the precompression stress (Pc) is calculated using the pedotransfer functions (PTFs) proposed by Horn and Fleige (2003). These PTFs involve eight parameters linked to the hydraulic and mechanical behaviour of soils: organic matter content, bulk density, air capacity, available and non-plant available water capacity, saturated hydraulic conductivity, cohesion and angle of internal friction. The challenge consists in producing Pc maps at the regional scale for Wallonia. Those maps should also be accompanied by estimation uncertainty map. Finally, the results should be exploited to produce compaction risk maps according to various frequent scenarios. In this paper, a methodology is proposed, combining geostatistics and Monte Carlo simulations, to achieve these goals. [less ▲]

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See detailExcavation damaged zone modelling including hydraulic permeability evolution in unsaturated argilaceous rock
Pardoen, Benoît ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg

in Khalili, Nasser; Russell, Adrian R.; Khoshghalb, Arman (Eds.) Unsaturated Soils: Research & Applications (2014, July)

The drilling of galleries induces damage propagation in the surrounding medium and creates the Excavation Damaged Zone (EDZ) in which the material properties are modified. The prediction of the fracture ... [more ▼]

The drilling of galleries induces damage propagation in the surrounding medium and creates the Excavation Damaged Zone (EDZ) in which the material properties are modified. The prediction of the fracture structure and flow properties evolution within this zone are major issues especially in the context of underground nuclear waste storage. Since experimental results indicate that shear strain localisation appears prior to fractures, we model the EDZ with strain localisation in shear band mode using the coupled local second gradient model. The evolution of the intrinsic hydraulic permeability inside the fractures is taken into consideration as well as the influence of gallery ventilation on the rock desaturation. The numerical results provide information about the damaged zone extension, structure and behaviour with good correspondence to in situ measurements and observations. [less ▲]

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See detailEnhancement of ray tracing method for radiative heat transfer with new isocell quasi-monte carlo technique and application to EUI space instrument
Jacques, Lionel ULg; Masset, Luc ULg; Kerschen, Gaëtan ULg

in Proceedings of the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, HEFAT2014 (2014, July)

Monte Carlo ray tracing method for thermal analysis. The rationale for this research is the speed-up of radiative heat transfer computation with the Finite Element Method, widely used in mechanical ... [more ▼]

Monte Carlo ray tracing method for thermal analysis. The rationale for this research is the speed-up of radiative heat transfer computation with the Finite Element Method, widely used in mechanical engineering especially for space structure design but not yet often for thermal analysis of these structures. Based on Nusselt’s analogy, the ray direction sampling is done by sampling the unit disc to derive the ray directions. Stratified sampling is applied to the unit disc that is divided into cells or strata into which random points are generated. The isocell method relies on cells that have the particularity of presenting almost the same area and shape. This enhances the uniformity of the generated quasi-random sequence of ray directions and leads to faster convergence. The isocell method is associated with different surface sampling to derive REFs. The method is benchmarked against ESARAD, the standard ray tracing engine of the thermal analysis software used in the European aerospace industry. Various geometries are used. In particular, one entrance baffle of the Extreme Ultraviolet Imager (EUI) instrument developed at the Centre Spatial de Liège in Belgium is presented. The EUI instrument of the Solar Orbiter European Space Agency mission and will be launched in a 0.28 perihelion orbit around the Sun in 2018. [less ▲]

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See detailAt the Crossroads of Greek and Roman Medicine: the Contribution of Latin Papyri. I. Medical Texts
Marganne, Marie-Hélène ULg

in Maire, Brigitte (Ed.) 'Greek' and 'Roman' in Latin Medical Texts. Studies in Cultural Change and Exchange in Ancient Medicine (2014, July)

Far fewer Latin medical papyri, whether paraliterary, documentary or magical, have survived compared to Greek medical papyri, but they nonetheless provide interesting information about medical practices ... [more ▼]

Far fewer Latin medical papyri, whether paraliterary, documentary or magical, have survived compared to Greek medical papyri, but they nonetheless provide interesting information about medical practices in the Graeco-Roman world, the relationship between Greek and Latin medical languages, and the choices made to use one rather than the other, a subject that has never been exhaustively studied. As part of the update undertaken by CEDOPAL since 2008 of the Corpus Papyrorum Latinarum, published fifty years ago by the late Robert Cavenaile, we have inventoried Latin papyri containing medical references, classifying them by type or nature of content, provenance, form, layout and writing. We finally analyse their content and what it reveals about the reception of Greek medicine by Latin or Latin-speeking writers. [less ▲]

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See detailMovements of endemic and exotic fish in a large river ecosystem (Rhône, France)
Capra, Hervé; Pella, Hervé; Ovidio, Michaël ULg

in Proceedings of the 10th International Conference on Ecohydraulics (2014, July)

The aim of this study is to characterise the mobility templates of two patrimonial species of rheophilic cyprinids (Barbus barbus and Squalius cephalus) and of a species of exotic fish, the catfish ... [more ▼]

The aim of this study is to characterise the mobility templates of two patrimonial species of rheophilic cyprinids (Barbus barbus and Squalius cephalus) and of a species of exotic fish, the catfish (Silurus glanis), in an area of the upper Rhône River characterised by significant disruptions of flow and thermal regimes (caused by hydroelectric and nuclear power plants). Results reveal contrasted mobility patterns, habitat uses and home-range sizes between endemic and exogenous fish species, but with a high interindividual variability. [less ▲]

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See detail3D analysis and determination of stride parameters for different type of foot strike in running
Bury, Thierry ULg

in Abstract book of the 19th Annual Congress of the ECSS Amsterdam (2014, July)

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See detailSoil compaction resulting from different soil tillage systems
Destain, Marie-France ULg; Roisin, Christian; Mercatoris, Benoît ULg

in ASABE - CSBE/ASABE Joint Meeting Presentation (2014, July)

The effects of long-term use (8 years) of two different tillage systems were assessed on a Luvisol, under temperate climate (Belgium). The tillage treatments were (i) conventional tillage (CT) with ... [more ▼]

The effects of long-term use (8 years) of two different tillage systems were assessed on a Luvisol, under temperate climate (Belgium). The tillage treatments were (i) conventional tillage (CT) with moldboard ploughing to 27 cm depth and (ii) reduced tillage (RT) with a spring tine cultivator to 10 cm depth. The measurements included bulk density (BD) and precompression stress (Pc) chosen as indicators of mechanical strength, and the pore size distribution (PSD) measured by mercury intrusion porosimetry (MIP). The tillage systems, the depth and their interaction had a significant effect on BD, Pc and PSD. In CT, in the topsoil, the soil strength was low and the total porosity n was about 50 %. In the subsoil, n decreased to 43 %. The PSD of CT was uni-modal in topsoil and subsoil in the MIP measurement range. The mean value of the mode rmax diminished from the topsoil toward the subsoil (from 2.5 microns to 1.9 microns). In RT, in the topsoil, the soil strength was higher than CT. BD did not vary much according to the depth. The total porosity n of RT was comprised between 40-45 % in the soil profile. The PSD was uni-modal and rmax increased from topsoil (around 2 microns) to subsoil (> 3 microns). This suggested the agglomeration of fine particles under the long-term action of mechanical loads, climatic agents, biological organisms or clay minerals acting as cementing agents. These phenomena could be at the origin of the increase of Pc with the depth without significant modification of BD. Such high values of Pc could be responsible of negative effects on root-growth leading to a more superficial root lateral development. [less ▲]

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See detailOrder reduction in time integration caused by velocity projection
Arnold, Martin; Cardona, Alberto; Bruls, Olivier ULg

in Proceedings of the 3rd Joint International Conference on Multibody System Dynamics and the 7th Asian Conference on Multibody Dynamics (2014, July)

Holonomic constraints restrict the configuration of a multibody system to a subset of the configuration space. They imply so called hidden constraints at the level of velocity coordinates that may ... [more ▼]

Holonomic constraints restrict the configuration of a multibody system to a subset of the configuration space. They imply so called hidden constraints at the level of velocity coordinates that may formally be obtained from time derivatives of the original holonomic constraints. A numerical solution that satisfies hidden constraints as well as the original constraint equations may be obtained considering both types of constraints simultaneously in each time step (stabilized index-2 formulation) or using projection techniques. Both approaches are well established in the time integration of differential-algebraic equations. Recently, we have introduced a generalized- alpha Lie group time integration method for the stabilized index-2 formulation that achieves second order convergence for all solution components. In the present paper, we show that a separate velocity projection would be less favourable since it may result in an order reduction and in large transient errors after each projection step. This undesired numerical behaviour is analysed by a one-step error recursion that considers the coupled error propagation in differential and algebraic solution components. This one-step error recursion has been used before to prove second order convergence for the application of generalized-alpha methods to constrained systems. As a technical detail, we discuss the extension of these results from symmetric, positive definite mass matrices to the rank deficient case. [less ▲]

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See detailExperimental analysis of 2:1 modal interactions with noncommensurate linear frequencies in an aerospace structure
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Kerschen, Gaëtan ULg

in Proceedings of the 8th European Nonlinear Dynamics Conference (ENOC) (2014, July)

Nonlinear interactions between modes with noncommensurate linear frequencies are studied. It is experimentally evidenced that a strongly nonlinear, full-scale aerospace structure may exhibit such 2:1 ... [more ▼]

Nonlinear interactions between modes with noncommensurate linear frequencies are studied. It is experimentally evidenced that a strongly nonlinear, full-scale aerospace structure may exhibit such 2:1 interactions in typical testing conditions. The experimental observations are compared with numerical predictions. [less ▲]

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See detailFatigue index reproducibility in isokinetic testing
Paulus, Julien ULg; Croisier, Jean-Louis ULg; Bosquet, Laurent et al

in De Haan, Arnold; De Ruiter, Jo; Tsolakidis, Elias (Eds.) Book of abstracts (2014, July)

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See detailOn the convergence of relaxation schemes to couple phasor-mode and electromagnetic transients simulations
Plumier, Frédéric ULg; Geuzaine, Christophe ULg; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES General Meeting (2014, July)

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a ... [more ▼]

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a relaxation process is used, which consists of iterating between both models. The convergence properties of this relaxation process are investigated. The speed of convergence is assessed when the variables exchanged at the interface between both models are respectively pure voltage/current sources, Norton/Thévenin equivalents, or a combination of them. Iteratively updated Norton/Thévenin equivalents are shown to drastically reduce the number of relaxation iterations. [less ▲]

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See detailOrthanc - Logiciel libre pour l'imagerie médicale en milieu hospitalier
JODOGNE, Sébastien ULg; LENAERTS, Eric ULg; COUCKE, Philippe ULg et al

in Communications de la Conférence Francophone en Gestion et Ingénierie des Systèmes Hospitaliers (GISEH 2014) (2014, July)

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See detailVibration analysis by speckle interferometry with CO2 lasers and microbolometers arrays
Vandenrijt, Jean-François ULg; Thizy, Cédric ULg; Georges, Marc ULg

in Imaging and Applied Optics 2014, OSA Technical Digest (online) (2014, July)

Speckle interferometry in the time-average mode in long wave infrared is shown for observing the mode shapes of vibrating objects. The long wavelength allows observing larger vibration displacements than ... [more ▼]

Speckle interferometry in the time-average mode in long wave infrared is shown for observing the mode shapes of vibrating objects. The long wavelength allows observing larger vibration displacements than what is achieved with visible wavelengths. [less ▲]

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See detailTassili n’Ajjer (Sahara Oriental Algérien) – Résultats préliminaires sur le Silurien-Dévonien
Djouder, Hocine ULg; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in Journée Thématique de l’Association des Sédimentologistes Français (ASF) « Diagenèse : avancées récentes et perspectives » (2014, July)

Les gisements atypiques non-conventionnels, à roches sédimentaires faiblement perméables, ainsi que les « sources rocks » constituent une source pétrolière majeure, attirant de plus en plus l’industrie ... [more ▼]

Les gisements atypiques non-conventionnels, à roches sédimentaires faiblement perméables, ainsi que les « sources rocks » constituent une source pétrolière majeure, attirant de plus en plus l’industrie pétrolière, d’où un regain d’intérêt potentiel au sein du Bassin de Berkine. En effet, rien que les argiles radioactives (‘hot’) shales du Silurien sont à l’origine de 80 à 90% des hydrocarbures de la plaque Nord-africaine, et les argiles radioactives du Frasnien (source secondaire) avec des valeurs de TOC allant jusqu’à 14% (Lüning et al., 2000). L'objectif de la thèse s’agira dans un premier temps de l’analyse des diagraphies de forages (Berkine ‘subsurface’) conditionnée aux données de terrain (Tassili n’Ajjer sur affleurements) et de sismique réflexion. Ceci afin de réaliser la modélisation 2D et 3-D des corps réservoirs et de la roche mère, à l’aide du logiciel Petrel©. Et au final, la cartographie des unités de la série Silurien-Dévonien dans le but de définir les « Plays » potentielles aux futures plans d’exploration. Au second volet, la mise au point d’une méthodologie rigoureuse, permettant l’étude minéralogique et l’évolution diagénétique des faciès, sous différents aspect ; la quantification de la porosité, la définition des relations entre porosité et minéralogie. Ensuite caractériser les argiles radioactives du Llandoverien-Frasnien respectivement Silurien, Dévonien et minéraux associés (Lüning et al., 2004). Plus précisément les processus et mécanismes qui contrôlent les transformations des minéraux argileux (minéralogies et cristallochimies) en composante latérale mais aussi en fonction de la profondeur. Dans ce contexte, des missions de terrains seront entreprises dans les massifs du Fadnoun (Tassili Central), Oued Taïni, Oued Khabkhab ainsi que dans l’Oued Amassine (Tassili Occidental) qui nous permettront de décrire en surface les formations du Siluro-Dévonien (profondément étudiées par : Asses, A., 1987 - Massa, D., 1988 - Bekkouche, D., 1992 – IFP, Sonatrach, Beicip., 1999) qui renferment les argiles radioactives (‘hot’) shales et les niveaux réservoirs, situées à quelques centaines de kilomètres au Nord (Bassin de Berkine), sous 2500 à 3000 m de sédiments. Une première mission de terrain est déjà réalisée, ayant reçu un support financier de la R&D (Séjour de Recherche à l’étranger), ainsi que des facilitées administratives et logistiques respectivement du Ministère de la Culture et de l’office national du parc culturel du Tassili n’Ajjer (patrimoine mondial de l’UNESCO depuis 1982). D’autres missions ultérieures seront à organiser en fonction du planning du déroulement de la thèse. La première mission géologique de terrain a duré un mois sur le Plateau de Fadnoun (Tassili n’Ajjer central). Ceci dans différentes coupes géologique-type des affleurements du Silurien-Dévonien : l’Oued Imihrou, l’Oued Farzal, Gara Tihouririne (sur la route Illizi-Fort Tarat) et Isoutar (Djouder et al., 2014). Durant cette mission terrain nous avons pu assurer la concordance entre les thématiques et objectifs de départ et les réalisés sur terrain, entre autre : 1) la meilleure compréhension de la géométrie des corps sédimentaires, au sein du Plateau de Fadnoun et donc par extension dans le bassin ; 2) la description et l’analyse des faciès, grâce aux affleurements peu connus dans les oueds. Ils permettront une analyse, notamment en termes d’environnements sédimentaires, des formations du Silurien-Dévonien ; 3) application première dans son genre de la susceptibilité magnétique comme nouvel proxy, pour les corrélations lithostratigraphiques des unités du Silurien-Dévonien aux Tassilis. 4) réalisation d’un échantillonnage serré à différents niveaux pour couvrir tout l’intervalle de la dépression intra-Tassilienne et des Grès du Tassili Externe, et puis l’expédition du matériel, nécessaire aux analyses de laboratoires notamment à Liège, et collaborateurs. La confection de lames-minces (en cours) permettra l’étude de la minéralogie et de la pétrographie, et donc une meilleure compréhension des faciès et microfaciès, c’est à dire de leurs propriétés intrinsèques (systèmes hétérogènes et complexes). Les lames palynologiques permettront des datations précises de chaque niveau. Enfin, différentes analyses sur roche (minéraux argileux dans un Laboratoire partenaire de l’Université de Poitiers en France, susceptibilité magnétique, cathodoluminescence, analyses géochimiques des majeurs et des traces à l’ULg) permettront d’affiner les paramètres du paléoenvironnement (Da Silva et al., 2013). [less ▲]

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See detailUpdate on investigation in IPF - Clinical presentation and epidemiology in domestic animals
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