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See detailRelationship between Stroke Volume and Pulse Wave Velocity
Kamoi, Shun; Pretty, Christopher; Chiew, Yeong Shiong et al

in Preprints of the 9th IFAC Symposium on Biological and Medical Systems (2015, September)

Stroke Volume (SV) measurements are essential for evaluating patient hemodynamic status and response to therapy. However, current methods for monitoring SV require either invasive or non- invasive ... [more ▼]

Stroke Volume (SV) measurements are essential for evaluating patient hemodynamic status and response to therapy. However, current methods for monitoring SV require either invasive or non- invasive additional measurements. This study investigates the relationship between SV and Pulse Wave Velocity (PWV) to examine whether the value of PWV can capture the changes in SV. The analysis was performed using data from six porcine experiments (N=6 Pietrain Pigs, 20-29 kg) in which left ventricular volume, aortic arc pressure, and descending aortic pressure waveforms were measured simultaneously. From the measured data, correlation coefficients were determined between absolute value of aortic PWV, SV and trend value ‘PWV – mean PWV’, ‘SV – mean SV’ during periods when changes in SV were induced from preload changes, as well as infusion of dobutamine. The results showed good correlation (r = 0.59) for trend value, however, the correlation coefficient were poor with r = 0.028 for absolute value across all pigs. The analysis showed that value of PWV is reliable for capturing trend value of SV in preload changes. However, it is unreliable for capturing absolute value of SV or changes in SV made from dobutamine. [less ▲]

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See detailChanges in biting characteristics recorded using the inertial measurement unit of a smartphone reflect differences in sward attributes
Andriamandroso, Andriamasinoro ULiege; Lebeau, Frédéric ULiege; Bindelle, Jérôme ULiege

in Guarino, Marcella; Berckmans, Daniel (Eds.) Precision Livestock Farming '15 (2015, September)

Accurate monitoring of grazing activity at individual cow level would provide useful information to farmers to improve the management of their animals and pastures in intensive dairy systems. Pasture ... [more ▼]

Accurate monitoring of grazing activity at individual cow level would provide useful information to farmers to improve the management of their animals and pastures in intensive dairy systems. Pasture attributes, starting with sward height, influence grazing behaviour and bites characteristics. In an attempt to link sward height to an individual automated detection of biting behaviour, a series of recording sessions of 4×3 days were realized on a ryegrass pasture with two contrasting heights (5 and 15 cm) over the grazing season (from July to October) with 4 dry red-pied cows equipped with the inertial measurement unit (IMU) of a smartphone on a halter, recording acceleration data at 100Hz. The behaviours were video-recorded. The number of grazing bouts performed during grazing trends to increase when the grass is highest. Fourier transforms of acceleration data showed that grazing bouts were characterized by a distinctive acceleration peak which frequency ranged between 1.02Hz and 1.46Hz whatever the sward height. It corresponded to the uprooting of grass frequency in the biting movement when compared with the observation in the video recordings and it could be used to improve automated grazing behaviour detection and to remotely characterize bites. These results show that some bite characteristics are influenced by sward height and automated individual monitoring of grazing behaviour is possible. An extension of this methodology should allow analysing more deeply the grazing behaviour of cattle in order to determine number of bites and possibly to link it to biomass intake. [less ▲]

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See detailSimple Median-Based Method for Stationary Background Generation Using Background Subtraction Algorithms
Laugraud, Benjamin ULiege; Pierard, Sébastien ULiege; Braham, Marc ULiege et al

in New Trends in Image Analysis and Processing - ICIAP 2015 Workshops (2015, September)

The estimation of the background image from a video sequence is necessary in some applications. Computing the median for each pixel over time is effective, but it fails when the background is visible for ... [more ▼]

The estimation of the background image from a video sequence is necessary in some applications. Computing the median for each pixel over time is effective, but it fails when the background is visible for less than half of the time. In this paper, we propose a new method leveraging the segmentation performed by a background subtraction algorithm, which reduces the set of color candidates, for each pixel, before the median is applied. Our method is simple and fully generic as any background subtraction algorithm can be used. While recent background subtraction algorithms are excellent in detecting moving objects, our experiments show that the frame difference algorithm is a technique that compare advantageously to more advanced ones. Finally, we present the background images obtained on the SBI dataset, which appear to be almost perfect. The source code of our method can be downloaded at http://www.ulg.ac.be/telecom/research/sbg. [less ▲]

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See detailNon-adiabatic study of the Kepler subgiant KIC 6442183
Grosjean, Mathieu ULiege; Dupret, Marc-Antoine ULiege; Belkacem, Kevin et al

in The Space Photometry Revolution CoRoT Symposium 3, Kepler KASC-7 joint meeting (2015, September)

Thanks to the precision of Kepler observations, [3] were able to measure the linewidth and amplitude of individual modes (including mixed modes) in several sub- giant power spectra. We perform a forward ... [more ▼]

Thanks to the precision of Kepler observations, [3] were able to measure the linewidth and amplitude of individual modes (including mixed modes) in several sub- giant power spectra. We perform a forward modelling of a Kepler subgiant based on sur- face properties and observed frequencies. Non-adiabatic computations including a time- dependent treatment of convection give the lifetimes of radial and non-radial modes. Next, combining the lifetimes and inertias with a stochastic excitation model gives the ampli- tudes of the modes. We can now directly compare theoretical and observed linewidths and amplitudes of mixed-modes to obtain new constraints on our theoretical models. [less ▲]

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See detailValidation and test cases for a free surface SPH model
Goffin, Louis ULiege; Erpicum, Sébastien ULiege; Dewals, Benjamin ULiege et al

in Advances in hydroinformatics - Simhydro 2014 (2015, September)

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See detailTHE SILURO – DEVONIAN SUCCESSIONS IN THE TASSILI N'AJJER OUTCROPS (SE, ALGERIA): SEDIMENTOLOGY AND STRATIGRAPHY
Djouder, Hocine ULiege; Boulvain, Frédéric ULiege; Da Silva, Anne-Christine ULiege et al

in IGCP 596 - SDS SYMPOSIUM : Climate change and Biodiversity patterns in the Mid-Palaeozoic (2015, September)

The sedimentary basins of North Africa have been accumulated a thick sedimentary succession of Palaeozoic, especially Siluro – Devonian sediments. These successions have been deposited in wide sags and ... [more ▼]

The sedimentary basins of North Africa have been accumulated a thick sedimentary succession of Palaeozoic, especially Siluro – Devonian sediments. These successions have been deposited in wide sags and sub-basins in a cratonic setting, along the northwestern passive margin of the Gondwana. This sedimentation is mainly controlled by rapid eustatic sea-level variations and by the opening of the proto-Tethyan Ocean during the Early Palaeozoic (Beuf et al., 1971; Boot et al., 1998). During this Siluro-Devonian Period, a high subsidence occurred, allowing a high pile of sediments and organic-rich shales were deposited in many places that form important hydrocarbon reservoirs and source rocks throughout North Africa basins and Middle East (Lüning et al., 2000). In the prolific Illizi and Berkine basins (Western Ghadames, Algeria) a basin-wide approach is needed, especially with the new “shale gas and shale oil” frontier in the upcoming years, in order to capture regional trends and re-assessment the Siluro-Devonian successions. Our project focuses on the Berkine Basin and its margin, which covers nearly 102.000 km2. This basin includes a thick sedimentary series of 7000 m corresponding to complex reservoirs but also black shales of the basal Silurian and Frasnian, which are respectively major and secondary source rock systems. Complete logging of spectacular large-scale and well exposed outcrops of the Siluro-Devonian sediments was carried out at the south margin (SE, Tassili n’Ajjer) of the Illizi-Berkine basins (Djouder et al., 2012; Djouder et al., 2014). The following analysis incorporates biostratigraphic, ichnological, sedimentological, Magnetic susceptibility (MS) and high resolution stratigraphic data. It would allow providing a framework of deposits, ranging from offshore to deltaic deposits for the Silurian and from fluvial to normal-marine depositional conditions for the Devonian. References Cited: Beuf, S., Biju-Duval, B., De Charpal, O., Rognon, P., Gariel, O., Bennacef, A., 1971. Les Grès du Paléozoïque inférieur au Sahara : Sédimentation et Discontinuité, Évolution Structurale d’un Craton. Publication de l‘Institut Français du Pétrole. N° 18, Edition Technip, Paris. p. 464. Boote, D.R.D., Clark-Lowes, D.D., Traut, M.W., 1998. Palaeozoic petroleum systems of North Africa. In: Macgregor, D.S., Moo- dy, R.T.J., Clark-Lowes, D.D. (Eds.), Petroleum Geology of North Africa. Geol. Soc. London Sp. Publ., vol. 132, pp. 7–68. Lüning, S., Craig, J., Loydell, D.K., Štorch, P., Fitches, B., 2000. Lower Silurian ‘hot shales’ in North Africa and Arabia: regional distribution and depositional model. Earth-Science Reviews, vol. 49, pp. 121-200. Djouder, H., Pagel, M., Murat, B., Orsingher, M., 2012. Le Silurien du Bassin de Berkine. Projet « Shale Gas » Profond. 10éme Colloque du Groupe Français des Argiles, Présentation Orale, Limoge, France 14-18 Mai 2012. http://hdl.handle.net/2268/171556 Djouder, H., Boulvain, F., Da Silva, A-C., Cornet, P., Lüning, S., 2014. Tassili n’Ajjer (Sahara Oriental Algérien) – Résultats préliminaires sur le Silurien – Dévonien : Journée Thématique de l’Association des Sédimentologistes Français (ASF) – Diagenèse : avancées récentes et perspectives, Présentation Poster, Orsay-Paris, France 04 Juillet 2014. http://hdl.handle.net/2268/171557 [less ▲]

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See detailERT monitoring sheds light on the hydrogeological behavior in a landfill
Dumont, Gaël ULiege; Nguyen, Frédéric ULiege

in EarthDoc - Near Surface Geoscience 2013 – 21th European Meeting of Environmental and Engineering Geophysics (2015, September)

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See detailModel refinements of transformers via a subproblem finite element method
Dular, Patrick ULiege; Kuo-Peng, Patrick; Ferreira da Luz, Mauricio et al

in Proceedings of ISEF 2015 (2015, September)

A progressive modeling of transformers is performed via a subproblem finite element method. A complete problem is split into subproblems with different adapted overlapping meshes. Model refinements are ... [more ▼]

A progressive modeling of transformers is performed via a subproblem finite element method. A complete problem is split into subproblems with different adapted overlapping meshes. Model refinements are performed from ideal to real flux tubes, 1-D to 2-D to 3-D models, linear to nonlinear materials, perfect to real materials, single wire to volume conductor windings, and homogenized to fine models of cores and coils, with any coupling of these changes. The proposed unified procedure efficiently feeds each subproblem via interface conditions, which lightens mesh-to-mesh sources transfers, and quantifies the gain given by each refinement on both local fields and global quantities. [less ▲]

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See detailIntegrated multi-sensor system for parallel in-situ monitoring of cell nutrients, metabolites and cell mass in biotechnological processes
Mross, S; Zimmerman, T; Winkin, N et al

in Proc. Eurosensors, CS02-1 (2015, September)

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See detailChallenging land fragmentation thanks a mobile milking robot: Statement of 2 cases of implementation: Liège and Trevarez experimental farms
Brocard, Valérie; Dufrasne, Isabelle ULiege; Lessire, Françoise ULiege et al

in Conington, J; Klopcic, M; Lauridsen, C (Eds.) et al Book of abstracts of the 66th annual meeting of the European Federation of Animal Science (2015, September)

Cette présentation fait le point de l'expérience de l'utilisation de 2 robots mobiles, développés comme prototypes à la Ferme expérimentale de Trévarez et à l'Université de Liège

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See detailA feasibility study for a self-oscillating loop for a three degree of freedom coupled MEMS resonator force sensor
Zhao, C; Wood, GS; Pu, SH et al

in Proc. Eurosensors MP-L01 (2015, September)

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See detailLocal Treatment for Monochrome Outdoor Painted Metal Sculptures: Assessing the suitability of conservation paints for retouching
van Basten, Nikki; Defeyt, Catherine ULiege; Rivenc, Rachel

in Conservation of Sculpture Parks (2015, September)

When outdoor painted sculptures get chipped, scratched or abraded, conservators might consider local retouching treatments as an option that would protect the exposed metal substrate and restore the ... [more ▼]

When outdoor painted sculptures get chipped, scratched or abraded, conservators might consider local retouching treatments as an option that would protect the exposed metal substrate and restore the aesthetic integrity, thus postponing a very costly and invasive overall repainting. Unfortunately, matching colour gloss and texture on large monochrome surfaces is always challenging. This paper reports on research undertaken to investigate some of the materials and application techniques that could be used to improve the matching of local areas of inpainting as part of a broader maintenance strategy for painted works in sculpture parks, and discusses some of the advantages and disadvantages of working with both industrial products and conservation materials. Previous work by the lead author investigated the use of industrial paints to retouch monochrome painted metal sculptures, using Claes Oldenburg’s Trowel (1971) from the Kröller-Müller Museum as a case study. Several industrial products were tested and for Trowel it was found that using a paint of the same type as the original, manipulated to modify its gloss and colour, gave the best results. However, the original paint is not always available on the market because of product discontinuation or paint formulations changing over the years, and so research on alternative products was carried out at the Getty Conservation Institute. Instead of investigating industrial paint systems, a range of conservation paints and products that are usually employed in indoor applications were tested. Although these materials are unlikely to match the durability of industrial products in outdoor settings, they offer a number of advantages that might make them appropriate for temporary treatments, including a better workability for colour and gloss adjustments, a generally easier application procedure, better availability in small quantities, and a lower cost than their industrial counterparts. For the present study, a matte industrial paint that was recently developed as a coating for Alexander Calder sculptures was used as the target surface. Various conservation retouching paints were selected and used to retouch mock-ups prepared with these matte industrial paints, which were damaged with scratches and other mechanical means to reproduce typical damage to painted sculpture. The simulated scratches and losses were first primed and filled using materials that were selected in consultation with conservators and the paint industry. Since the composition of some of these products was unclear they were analysed and determined. The retouching was then carried out as a last step, applying the paint with an airbrush and using an ‘over-the-edge spray technique’. Some of the retouching paints were modified following the advice of the manufacturer to improve workability or durability. The colour retention of the various products is currently being tested with artificial aging in a weatherometer; the adhesion of the local treatment and the compatibility with the overall paint will be tested with the mock-ups placed outdoors for an extended period of time. Preliminary results show that the workability of some of the products tested is satisfying and that the retouching, when carried out properly, reintegrates both the paint coherence and the visual aspect of the artwork. [less ▲]

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See detailStellar acoustic radii and ages from seismic inversion techniques
Buldgen, Gaël ULiege; Dupret, Marc-Antoine ULiege; Reese, Daniel Roy et al

in The Space Photometry Revolution CoRoT Symposium 3, Kepler KASC-7 joint meeting (2015, September)

Determining stellar characteristics such as the radius, mass or age is crucial and asteroseismology is currently the most promising tool to provide these results accurately. We extend the SOLA inversion ... [more ▼]

Determining stellar characteristics such as the radius, mass or age is crucial and asteroseismology is currently the most promising tool to provide these results accurately. We extend the SOLA inversion technique to new global characteristics in addition to the mean density (see Reese et al. 2012) and apply our methodology to the acoustic radius and an age indicator based on the sound speed derivative. The results from SOLA inversions are compared with estimates based on the small and large frequency separations for several test cases.We show that SOLA inversions yield more accurate results than other techniques which are more sensitive to surface effects. [less ▲]

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See detailStudy of ingredients and chemical composition of snacks for dogs
Ricci, Rebecca; Morelli, G.; Fusi, Eleonora et al

in Priymenko, Nathalie; Janssens, Geert; Harris, Patricia (Eds.) Congress Proceedings of the 19th ESVCN Congress (2015, September)

Snacks (n=41) for dogs showed a wide variability in chemical composition; most of them were composed by numerous ingredients, often identified as categories, among which simple sugars and sweeteners.

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See detailSurvey on the attitude of dogs' owners on the use of snacks
Ricci, Rebecca; Morelli, Giada; Fusi, Eleonora et al

in Priymenko, Nathalie; Janssens, Geert; Harris, Patricia (Eds.) Congress Proceedings of the 19th ESVCN congress (2015, September)

Results of a study of 2217 dog's owners about the use of snacks.

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See detailMass sensor utilising the mode-localisation effect in an electrostatically-coupled MEMS resonator pair fabricated using an SOI process
Wood, Graham; Chun, Zhao; Pu, Suan et al

in Proceedings 41st Micro and Nano Engineering Conference (2015, September)

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See detailDiscours, violence, civilité
Delruelle, Edouard ULiege

in De Smet, François (Ed.) La liberté d'expression, menacée ou menaçante ? (2015, September)

La question philosophique et politique pertinente est celle des conditions de la liberté d'expression, pas celle de ses limites. La véritable question est : quelles sont les conditions pour que la liberté ... [more ▼]

La question philosophique et politique pertinente est celle des conditions de la liberté d'expression, pas celle de ses limites. La véritable question est : quelles sont les conditions pour que la liberté d’expression soit une liberté effective pour tous — pour l’athée comme pour le croyant, l’employé comme l’employeur, l’allochtone comme l’autochtone, le fou comme le sain d’esprit, le chômeur comme le professeur d’Université, etc. ? [less ▲]

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See detailEstimation of Airline Itinerary Choice Models Using Disaggregate Ticket Data
Lurkin, Virginie ULiege; Garrow, Laurie A.; Higgins, Matthew J. et al

in 55th AGIFORS Annual Proceedings 2015 (2015, August 29)

Airline itinerary choice models support many multi-million dollar decisions, i.e., they are used to evaluate potential route schedules. Classic models suffer from major limitations, most notably they use ... [more ▼]

Airline itinerary choice models support many multi-million dollar decisions, i.e., they are used to evaluate potential route schedules. Classic models suffer from major limitations, most notably they use average fare information but to not correct for price endogeneity. We use a novel database of airline tickets to estimate itinerary choice models using detailed fare data and compare these to classic itinerary choice models that use aggregate fare information but correct for price endogeneity. [less ▲]

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See detailCommon serial order processes in musical and verbal short-term memory: evidence from a novel serial order probe recognition paradigm
Gorin, Simon ULiege; Majerus, Steve ULiege

in Ginsborg, Jane; Lamont, Alexandra; Philips, M (Eds.) et al Proceedings of the Ninth Triennial Conference of the European Society for the Cognitive Sciences of Music (2015, August 21)

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See detailA principle of similarity for nonlinear vibration absorbers
Habib, Giuseppe ULiege; Kerschen, Gaëtan ULiege

in 11th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (2015, August 05)

With continual interest in expanding the performance envelope of engineering systems, nonlinear components are increasingly utilized in real-world applications. This causes the failure of wellestablished ... [more ▼]

With continual interest in expanding the performance envelope of engineering systems, nonlinear components are increasingly utilized in real-world applications. This causes the failure of wellestablished techniques to mitigate resonant vibrations. In particular, this holds for the linear tuned vibration absorber (LTVA), which requires an accurate tuning of its natural frequency to the resonant vibration frequency of interest. This is why the nonlinear tuned vibration absorber (NLTVA), the nonlinear counterpart of the LTVA, has been recently developed. An unconventional aspect of this absorber is that its restoring force is tailored according to the nonlinear restoring force of the primary system. This allows the NLTVA to extend the so-called Den Hartog’s equal-peak rule to the nonlinear range. In this work, a fully analytical procedure, exploiting harmonic balance and perturbation techniques, is developed to define the optimal value of the nonlinear terms of the NLTVA. The developments are such that they can deal with any polynomial nonlinearity in the host structure. Another interesting feature of the NLTVA, discussed in the paper, is that nonlinear terms of different orders do not interact with each other in first approximation, thus they can be treated separately. Numerical results obtained through the shooting method coupled with pseudoarclength continuation validate the analytical developments. [less ▲]

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See detailA propos des fonctions continues qui ne sont dérivables en aucun point
Esser, Céline ULiege

in Notes de la huitième Brussels Summer School of Mathematics (2015, August 03)

En 1872, Karl Weierstrass présenta non seulement une, mais toute une famille de fonctions continues et nulle part dérivables. Après la publication de ce résultat, beaucoup d'autres mathématiciens ... [more ▼]

En 1872, Karl Weierstrass présenta non seulement une, mais toute une famille de fonctions continues et nulle part dérivables. Après la publication de ce résultat, beaucoup d'autres mathématiciens apportèrent leur propre contribution en construisant d'autres fonctions continues et nulle part dérivables. Dans cet exposé, nous présenterons les fonctions de Weierstrass et nous montrerons que le théorème de Baire permet d'affirmer que l'ensemble des fonctions nulle part dérivables est dense dans l'ensemble des fonctions continues. Nous étudierons également la régularité ponctuelle des fonctions de Weierstrass en introduisant la notion d'exposant de Hölder. [less ▲]

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See detailThe optical blocking filter for the ATHENA wide field imager: ongoing activities towards the conceptual design
Barbera, M.; Branduardi-Raymont, G.; Collura, A. et al

in Siegmund, Oswald H. (Ed.) UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XIX (2015, August 01)

ATHENA is the L2 mission selected by ESA to pursue the science theme "Hot and Energetic Universe" (launch scheduled in 2028). One of the key instruments of ATHENA is the Wide Field Imager (WFI) which will ... [more ▼]

ATHENA is the L2 mission selected by ESA to pursue the science theme "Hot and Energetic Universe" (launch scheduled in 2028). One of the key instruments of ATHENA is the Wide Field Imager (WFI) which will provide imaging in the 0.1-15 keV band over a 40'x40' large field of view, together with spectrally and time-resolved photon counting. The WFI camera, based on arrays of DEPFET active pixel sensors, is also sensitive to UV/Vis photons. Optically generated electron-hole pairs may degrade the spectral resolution as well as change the energy scale by introducing a signal offset. For this reason, the use of an X-ray transparent optical blocking filter is needed to allow the observation of all type of X-ray sources that present a UV/Visible bright counterpart. In this paper, we describe the main activities that we are carrying on for the conceptual design of the optical blocking filter, that will be mounted on the filter wheel, in order to satisfy the scientific requirements on optical load from bright UV/Vis astrophysical source, to maximize the X-ray transmission, and to withstand the severe acoustic and vibration loads foreseen during launch. [less ▲]

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See detailGenetic heritage of the Eastern Belgium Red and White breed, an endangered local breed
Colinet, Frédéric ULiege; Bouffioux, Aude; Mayeres, Patrick et al

in Book of Abstracts of the 66th Annual Meeting of the European Federation of Animal Science (2015, August)

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See detailGenetic analysis to support the re-establishment of the Kempen breed
François, Liesbeth; Janssens, Steven; Colinet, Frédéric ULiege et al

in Book of Abstracts of the 66th Annual Meeting of the European Federation of Animal Science (2015, August)

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See detailOverview of possibilities and challenges of the use of infrared spectrometry in cattle breeding
Gengler, Nicolas ULiege; Soyeurt, Hélène ULiege; Dehareng, Frédéric et al

in Book of Abstracts of the 66th Annual Meeting of the European Federation of Animal Science (2015, August)

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See detailLes précédents. La bataille de Ravenna
Dumont, Jonathan ULiege

in Viganò, Marino (Ed.) Marignano 1515 : la svolta. Atti del congresso internazionale, Milano, 13 settembre 2014 (2015, August)

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See detailBrain Trains: Intermodal Rail Freight Transport and Hinterland Connections - A Swot Analysis to Assess the Belgian Rail Practice
Troch, Frank; Vanelslander, Thierry; Sys, Christa et al

in Proceedings of the IAME Annual Conference 2015 (2015, August)

This paper focuses on transversal research of the role and influences of rail freight transport, as a part of intermodal transport in Belgium. The scope of the research concentrates on port hinterland ... [more ▼]

This paper focuses on transversal research of the role and influences of rail freight transport, as a part of intermodal transport in Belgium. The scope of the research concentrates on port hinterland flows. A large SWOT analysis of the current situation is conducted, starting from the actual weak usage of this mode of transport. Five different fields have been identified, impacting the economy and society. Each field indicates critical internal strengths and weaknesses for intermodal rail transportation in Belgium, and identifies possible future developments and setbacks. A Delphi-like approach is used, including a heterogeneous panel of experts discussing and validating the SWOT results. To prioritize the characteristics, a survey on the different SWOT elements was performed, asking the experts to rate each statement on its influence and likelihood of happening (level of uncertainty). [less ▲]

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See detailComparison between thermographic and holographic techniques for nondestructive testing of composites: similarities, differences and potential cross-fertilization
Georges, Marc ULiege

in Mendoza Santoyo, Fernando (Ed.) SPECKLE 2015: VI International Conference on Speckle Metrology (2015, August)

Thermography and different variants of holography (holographic interferometry, speckle interferometry, shearography) are full-field non-contact techniques which are used in nondestructive testing ... [more ▼]

Thermography and different variants of holography (holographic interferometry, speckle interferometry, shearography) are full-field non-contact techniques which are used in nondestructive testing applications. In particular they are attractive for damage detection in composite materials compared to other methods measuring in one point and which require scanning and contact with the samples, like ultrasounds. Currently thermography is a step forward compared to holographic techniques for this application. Indeed it is easier to interpret. Many thermography configurations and variants exist, from exciting sources to post-processing. Such a variety exists also among the holographic techniques but to a less extent. We will see how these techniques can share some aspects and what distinguish them. Also the complementarity of both will be addressed and how to combine them. At last we will discuss how processing developed for thermography can benefit to holography and vice-versa, specifically in the domain of composite materials. [less ▲]

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See detailAgriculture Seen Through the Prism of the French Media in Belgium
Dubois, Charline ULiege

in Firmino, Ana (Ed.) Smart answers for a smiling future (2015, August)

Scholars agree on the importance of the farming activities to maintain the quality (aesthetic environment) of rural areas. The number of farmers in Belgium fall steadily in the recent decades (Van Hecke ... [more ▼]

Scholars agree on the importance of the farming activities to maintain the quality (aesthetic environment) of rural areas. The number of farmers in Belgium fall steadily in the recent decades (Van Hecke et al. 2010). In particular, the rural systems of Wallonia transformed, characterized by the increased presence of landscapes of consumption and the influx of urban migrants. Why do they live in the countryside? Do they know the farmers in the area? What are the rural idylls (Yarwood 2005)? The answers to these questions lead to the understanding of perceptions and recognitions of rural spaces among different stakeholders. On another scale, this leads to the need for the improvement of social and territorial cohesion to improve the quality of life and the integration of people into their new living environment. The topics about “to live and to build the countryside” are current (Cawley & Gillmor 2008, Frelat-Kahn & Lazzarotti 2012) and are also concerned with the future of the countryside, of farming, and of the vitality of rural systems that face challenges according to geographic situations. With increasing suburbanization and multifunctionality (Bills & Gross 2005), some inhabitants want to build an interdependent community with authentic values. But the inhabitants’ representations about rural way of life are inexistent (despite some local initiatives such as organic produces) or complex (Dubois & Schmitz 2011, Tencati & Zsolnai 2012). Each person can say that he/she lives in the countryside by considering different space realities, with the risk that farmers could become strangers (Simard & Guimond 2013)! “Each year we organised a party in our street with everybody from the surrounding areas. Some farmers come and it is amazing to socialize more than just pass each other by cars and tractors” (inhabitant in a rural town in Wallonia). This study presents a first step in exploring inhabitant’s representations of the countryside. We analyse here the organic image about agriculture developed by the media that partly influences the people's perception of agriculture. Other than the induced and experienced images, organic image or “those that arise from supposedly unbiased sources” such as books, school education, television, documentaries, newspapers, and word of mouth (Gunn 1972, O'Leary & Deegan 2005) is considered. “People are interested about agricultural features. We speak a lot about that in the media, so people would like to know more about us and our job! That is why they visit us and they are sometimes so disoriented!” (Farmer in Wallonia). The analysis focuses on 3 consecutive even-numbered years: 2010, 2012 and 2014, from January to December. The national online press platform was used to access the articles. This allows for an analytical look at how agriculture is represented in the newspapers: What themes were addressed? How often? And to know the level of importance, in which part of the newspapers did it appear? The study analysed articles from 2 Belgian French newspapers from different media groups (Le Soir, La Libre). Different regions were covered to take into account different agro-geographical landscapes, suburban and rural features of the countryside, and different social and economical realities of Wallonia. For each article, topic selection and content analysis (NVivo ) were undertaken. Bette (2012) made the first analysis of the topic in 2012 and put into evidence 13 different categories in which agriculture has been presented: organic, diversification, legislation, economy, crops, farming, food, biotechnology, energy, animal health, plant diseases, environment, other. However, for this research, we improved the typology and add other topics such as the tourism, the local produces, the (agro-) geographical regions. Qualitative analysis showed that economic difficulties, economic investment, local produces, slow food, European policies, environment are among the categories frequently explored. All the different categories were represented and were often sensationalised but the level of importance is not high as most news were often found inside the newspaper and not on the front page. These different elements influence the representations of the different readers and give an overview about the influence of images of agriculture on the inhabitants. Agriculture is related to multiple components but some of these aspects are not presented and remain unknown to the common public. A lot of other questions about agricultural and rural systems and agricultural regions are not covered because on-going social, economic environmental and cultural trends tend to influence the information that are found in the newspapers. Agriculture is often simplified in a positive (e.g. local products, organic farming) and in a negative way (e.g. pollutions, bankruptcies, suicides) which implied that it is difficult for laymen to have a valid representation based on newspapers. [less ▲]

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See detailTime-averaged phase-stepped ESPI with CO2 laser and shearography in the visible for identification of vibration mode shapes
Vandenrijt, Jean-François ULiege; Thizy, Cédric ULiege; Georges, Marc ULiege

in Mendoza Santoyo, Fernando (Ed.) SPECKLE 2015: VI International Conference on Speckle Metrology (2015, August)

We present investigation of interferometric methods for vibration mode identification to be applied on shakers in industrial environment. We consider long wave infrared ESPI in time-averaged mode with the ... [more ▼]

We present investigation of interferometric methods for vibration mode identification to be applied on shakers in industrial environment. We consider long wave infrared ESPI in time-averaged mode with the use of phase-stepping which allows transforming Bessel fringes, typical to the time averaging, into phase values which provide a better way for identification of vibration mode shapes. The use of long laser wavelength allows measuring larger amplitudes of vibrations compared to what is achieved in visible light. Also longer wavelengths allow lower sensitivity to external perturbations. Time-averaged phase-stepped shearography in visible is also used as a compared alternative to LWIR ESPI for working in industrial environments. Although not demonstrated here, an interesting feature for the future investigations on LWIR ESPI is its potentiality of simultaneous temperature measurement during vibrations [less ▲]

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See detailCombination of temporal phase unwrapping and long-wave infrared digital holographic interferometry for metrology of mosaic detector under space simulated conditions
Vandenrijt, Jean-François ULiege; Thizy, Cédric ULiege; Beaumont, Florent et al

in Mendoza Santoyo, Fernando (Ed.) SPECKLE 2015: VI International Conference on Speckle Metrology (2015, August)

We present digital holographic interferometry (DHI) in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array to be used in a space mission. The ... [more ▼]

We present digital holographic interferometry (DHI) in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array to be used in a space mission. The long wavelength was chosen for its ability to allow measurement of displacements 20 times larger than DHI in the visible and which were foreseen with the test object under such temperature changes. The specimen consists of 4x4 mosaic of detectors assembled on a frame. It was required to assess the global deformation of the ensemble, the deformation of each detector, and piston movements of each of them with respect to their neighbors. For that reason we incorporated the temporal phase unwrapping by capturing a sufficiently high number of holograms between which the phase does not suffer strong variations. At last since the specimen exhibit specular reflectivity at that wavelength, it is illuminated through a reflective diffuser [less ▲]

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See detailStroke Volume Estimation using Aortic Pressure Measurements and Aortic Cross Sectional Area: Proof of Concept
Kamoi, Shun; Pretty, Christopher G.; Chiew, Yeong Shiong et al

in Proceedings of the 37th International Conference of the IEEE Engineering in Medicine and Biology Society (2015, August)

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of ... [more ▼]

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of measurement devices. Current devices for indirect monitoring of SV are shown to be inaccurate during sudden hemodynamic changes. This paper presents a novel SV estimation using readily available aortic pressure measurements and aortic cross sectional area, using data from a porcine experiment where medical interventions such as fluid replacement, dobutamine infusions, and recruitment maneuvers induced SV changes in a pig with circulatory shock. Measurement of left ventricular volume, proximal aortic pressure, and descending aortic pressure waveforms were made simultaneously during the experiment. From measured data, proximal aortic pressure was separated into reservoir and excess pressures. Beat-to-beat aortic characteristic impedance values were calculated using both aortic pressure measurements and an estimate of the aortic cross sectional area. SV was estimated using the calculated aortic characteristic impedance and excess component of the proximal aorta. The median difference between directly measured SV and estimated SV was -1.4ml with 95% limit of agreement +/- 6.6ml. This method demonstrates that SV can be accurately captured beat-to-beat during sudden changes in hemodynamic state. This novel SV estimation could enable improved cardiac and circulatory treatment in the critical care environment by titrating treatment to the effect on SV. [less ▲]

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See detailModelling of the Nonlinear End-Systolic Pressure-Volume Relation and Volume-at-Zero-Pressure in Porcine Experiments
Davidson, Shaun M.; Kannangara, D. Oliver; Pretty, Christopher G. et al

in Proceedings of the 37th International Conference of the IEEE Engineering in Medicine and Biology Society (2015, August)

The End-Systolic Pressure-Volume Relation (ESPVR) is generally modelled as a linear relationship between P and V as cardiac reflexes, such as the baroreflex, are typically suppressed in experiments ... [more ▼]

The End-Systolic Pressure-Volume Relation (ESPVR) is generally modelled as a linear relationship between P and V as cardiac reflexes, such as the baroreflex, are typically suppressed in experiments. However, ESPVR has been observed to behave in a curvilinear fashion when cardiac reflexes are not supressed, suggesting the curvilinear function may be more clinically appropriate. Data was gathered from 41 vena cava occlusion manoeuvres performed experimentally at a variety of PEEPs across 6 porcine specimens, and ESPVR determined for each pig. An exponential model of ESPVR was found to provide a higher correlation coefficient than a linear model in 6 out of 7 cases, and a lower Akaike Information Criterion (AIC) value in all cases. Further, the exponential ESPVR provided positive V0 values in a physiological range in6 out of 7 cases analysed, while the linear ESPVR produced positive V0 values in only 3 out of 7 cases, suggesting linear extrapolation of ESPVR to determine V0 may be flawed. [less ▲]

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See detailOn the use of novel milk phenotypes as predictors of difficult-to-record traits in breeding programs
Bastin, Catherine ULiege; Colinet, Frédéric ULiege; Dehareng, Frédéric et al

in Book of Abstracts of the 66th Annual Meeting of the European Federation of Animal Science (2015, August)

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See detailPotential of visible-near infrared spectroscopy for the characterization of butter properties
Troch, Thibault ULiege; Baeten, Vincent; Dehareng, Frédéric et al

in Book of Abstracts of the 66th Annual Meeting of the European Federation of Animal Science (2015, August)

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See detailCritical metals in sphalerites from Belgian MVT deposits
Goffin, Vincent; Evrard, Maxime ULiege; Pirard, Eric ULiege

in André-Mayer, Anne-Sylvie; Cathelineau, Michel; Muchez, Philippe (Eds.) et al Proceedings of the 13th SGA Biennial Meeting (2015, August)

Belgium hosts a series of well documented low temperature, carbonate hosted, lead-zinc veins and lenses clearly categorized as MVT deposits. This paper revisits the distribution of trace elements in ... [more ▼]

Belgium hosts a series of well documented low temperature, carbonate hosted, lead-zinc veins and lenses clearly categorized as MVT deposits. This paper revisits the distribution of trace elements in sphalerites from Belgian deposits with a special focus on Ge, Ga and In. By comparing with a database of worldwide deposits, this paper shows that Belgian sphalerites do not display a classical substitution pattern involving Cu+. Instead, multivariate analysis points towards similarities with the Tres Marias deposit in Mexico, although the explanation of coupled substitution with Fe++ does not seem to apply in the present case. From the limited set of sphalerites analysed in this paper, the following rithmetic means are obtained: m(Ge) = 302 ppm, m(Ga) = 2.2 ppm and m(In) < 0.06 ppm. These average values should not hide the fact that a wide variability does exist from one deposit to the other and within zoned colloform sphalerites of the same deposit. Further nd systematic work is required to better evaluate the resource and understand the mechanisms responsible for Ge incorporation into sphalerite. [less ▲]

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See detailGenetic variability of MIR predicted milk technological properties in Walloon dairy cattle
Colinet, Frédéric ULiege; Troch, Thibault ULiege; Baeten, Vincent et al

in Book of Abstracts of the 66th Annual Meeting of the European Federation of Animal Science (2015, August)

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See detailIsolated response curves in a base-excited, two-degree-of-freedom, nonlinear system
Noël, Jean-Philippe ULiege; Detroux, Thibaut ULiege; Masset, Luc ULiege et al

in Proceedings of the ASME 2015 International Design Engineering Technical Conferences (2015, August)

In the present paper, isolated response curves in a nonlinear system consisting of two masses sliding on a horizontal guide are examined. Transverse springs are attached to one mass to provide the ... [more ▼]

In the present paper, isolated response curves in a nonlinear system consisting of two masses sliding on a horizontal guide are examined. Transverse springs are attached to one mass to provide the nonlinear restoring force, and a harmonic motion of the complete system is imposed by prescribing the displacement of their supports. Numerical simulations are carried out to study the conditions of existence of isolated solutions, their bifurcations, their merging with the main response branch and their basins of attraction. This is achieved using tools including nonlinear normal modes, energy balance, harmonic balance-based continuation and bifurcation tracking, and global analysis. [less ▲]

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See detailPhysical modeling of lateral dike breaching due to overtopping
Rifai, Ismail ULiege; Erpicum, Sébastien ULiege; Archambeau, Pierre ULiege et al

in River, Coastal and Estuarine Morphodynamics, RCEM 2015 (2015, August)

Dikes are commonly used as defense structures for river flow channelization, protecting population and property from floods and against lateral riverbed migration. However, the aging of these structures ... [more ▼]

Dikes are commonly used as defense structures for river flow channelization, protecting population and property from floods and against lateral riverbed migration. However, the aging of these structures, combined with their increased vulnerability to extreme hydrological events may cause the dikes to breach, and subsequently to break. Furthermore, statistics show that flow overtopping is the main cause of dike failure, which emphasizes the need to understand thoroughly the process of breaching. Indeed, from a risk management perspective it is particularly important to have a detailed understanding of the mechanisms (e.g. internal erosion, overtopping erosion) underlying the formation of breaches due to overtopping and reliable information on flows passing through them. Conversely, the current knowledge of breaching mechanisms remains fragmented, especially because dike failure involves complex interactions between flows, materials of the structure, soil and foundations. The existing studies have addressed partially these interactions as the considered idealized dikes were generally homogenous, the piping erosion unaccounted for and the overtopping replicated in a dam-break like configuration. Yet, river embankments are subjected to high flow velocities parallel to the direction of the dike and to flow in the floodplain, which highly influence the shape of the breach and its evolution. The objective of the present work is to fill this gap. A laboratory experimental investigation is planned in the National Laboratory for Hydraulics and Environment (LNHE) of EDF R&D (France) and in the research group Hydraulics in Environmental and Civil Engineering (HECE) of the University of Liege (Belgium), reproducing realistic configurations of river dikes, accounting for the tangential flow in both main channel and floodplain. It enables thus the assessment of, on the one hand, the effect of the increase of the water level, and on the other hand, the influence of waves. The laboratory tests also consider the effect of a surface layer and composition of the dike core by testing different material mixtures. Geometry and composition of the idealized dikes are representative of typical field dikes, based on the similarity theory. [less ▲]

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See detailBifurcation analysis of a spacecraft structure using the harmonic balance method
Detroux, Thibaut ULiege; Renson, Ludovic ULiege; Masset, Luc ULiege et al

in Proceedings of the ASME 2015 International Design Engineering Technical Conferences (2015, August)

The harmonic balance (HB) method has been widely used in the past few years, as a numerical tool for the study of nonlinear models. However, in its classical formulation the HB method is limited to the ... [more ▼]

The harmonic balance (HB) method has been widely used in the past few years, as a numerical tool for the study of nonlinear models. However, in its classical formulation the HB method is limited to the approximation of periodic solutions. The present paper proposes to extend the method to the detection and tracking of bifurcations in the codimension-2 system parameters space. To validate the methodology, the forced response of a real spacecraft is examined. The paper first provides some numerical evidence of the presence of quasiperiodic oscillations and isolated solutions. It then demonstrates how the tracking of Neimark-Sacker and fold bifurcations can help get a deeper understanding of these attractors. [less ▲]

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See detailGeophysical Investigation of the Pb-Zn deposit of Plombières, Belgium
Evrard, Maxime ULiege; Pirard, Eric ULiege; Nguyen, Frédéric ULiege

in André-mayer, anne-Sylvie; Cathelineau, Michel; Muchez, Philippe (Eds.) et al Mineral resources in a sustainable worl, proceeding, volume 5 (2015, August)

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See detailEthnic Differences in Travel Time Expenditure
Cools, Mario ULiege; Eftekhar, Hamed ULiege

in Proceeding of the 14th International Conference on Travel Behaviour Reresearch (IATBR 2015) (2015, July 23)

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See detailA viscoelastic-viscoplastic-damage constitutive model based on a large strain hyperelastic formulation for amorphous glassy polymers
Nguyen, Van Dung ULiege; Morelle, Xavier; Lani, Frédéric et al

in proceedings of the 20th International Conference on Composite Materials, Copenhagen, Denmark, 19-24th July 2015 (2015, July 20)

The aim of this work is to develop an efficient large-strain hyperelastic constitutive model for amorphous polymers in the glassy state. These materials exhibit a complex rate- and pressure-sensible ... [more ▼]

The aim of this work is to develop an efficient large-strain hyperelastic constitutive model for amorphous polymers in the glassy state. These materials exhibit a complex rate- and pressure-sensible behavior in both elastic and plastic regimes. After an initial linear elastic region, a nonlinear stage continues until reaching a peak stress, which is followed by a softening stage. At large strains, when the softening is saturated, a re-hardening stage is reached. The viscoelastic effect is captured using the generalized Maxwell model. The viscoplastic effect is considered using a Perzyna-type flow rule incorporating a pressure sensitive yield surface and a non-associated flow potential. This yield surface is extended from the Drucker-Prager one. The saturated softening phenomenon is modelled using an isotropic numerical damage variable progressed by a saturated softening law. With the introduction of the damage parameter, a non-local implicit gradient damage model is used to avoid the loss of the solution uniqueness. Through experimental comparisons, it is shown that the proposed model has the ability to model the complex mechanical responses of amorphous glassy polymers. [less ▲]

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See detailGenome Wide Association Study Reveals New Chromosome Regions Affecting Age at First Calving in Nellore Cattle
REIS MOTA, Rodrigo ULiege; Kelly, John Mathew; Rocha Wenceslau, Raphael et al

in 52ª Reunião Anual da Sociedade Brasileira de Zootecnia - Zootecnia: Otimizando Recursos e Potencialidades (2015, July 19)

: In the genomic-wide selection (GWS) era, the identification and use of molecular markers such as SNP allows the prediction and accuracy gain of genomic estimated breeding values (GEBV) for economically ... [more ▼]

: In the genomic-wide selection (GWS) era, the identification and use of molecular markers such as SNP allows the prediction and accuracy gain of genomic estimated breeding values (GEBV) for economically important traits. The objectives of this study were to estimate genetic parameters for age at first calving (AFC), to perform genome-enabled predictions in Nellore and well as to identify QTLs associated to the most relevant SNPs. acquired on 529 of these animals (24,572 SNPs). A multi-trait model was fitted under a MCMC Bayesian approach using a single step BLUP methodology. We identified 0.05% of the most relevant SNP for AFC as well as reported QTLs related with AFC. Heritability estimates were 0.18 and 0.41 for AFC and WW, respectively. The genetic correlation between AFC and WW was 0.06. The top 0.05% most relevant SNPs were detected on chromosomes 7, 9 14, 16, 18, 21, 24, 26 and 29. The most relevant SNP marker was detected on BTA14, when we so observed a peak which could reveal the importance of this chromosome for AFC. Moreover, we identified new regions that might be related with AFC. [less ▲]

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See detailExperimental study of Predictive Control strategies for optimal operation of Organic Rankine Cycle systems
Hernandez Naranjo, Jairo Andres ULiege; Desideri, Adriano ULiege; Ionescu, Clara et al

in Experimental study of Predictive Control strategies for optimal operation of Organic Rankine Cycle systems (2015, July 17)

In this paper the performance of Model Predictive Control (MPC) and PID based strategies to optimally recover waste heat using Organic Rankine Cycle (ORC) technology is investigated. First the ... [more ▼]

In this paper the performance of Model Predictive Control (MPC) and PID based strategies to optimally recover waste heat using Organic Rankine Cycle (ORC) technology is investigated. First the relationship between the evaporating temperature and the output power is experimentally evaluated, concluding that for some given heat source conditions there exists an optimal evaporating temperature which maximizes the energy production. Three different control strategies MPC and PID based are developed in order not only to maximize energy production but to ensure safety conditions in the machine. For the case of the MPC, the Extended Prediction Self-Adaptive Control (EPSAC) algorithm is considered in this study as it uses input/output models for prediction, avoiding the need of state estimators, making of it a suitable tool for industrial applications. The experimental results obtained on a 11kWe pilot plant show that the constrained EPSAC-MPC outperforms PID based strategies, as it allows to accurately regulate the evaporating temperature with a lower control effort while keeping the superheating in a safer operating range. [less ▲]

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See detailCrop supplemental irrigation experiences in Burkina Faso
Zongo, Bétéo ULiege; Diarra, Abdoulaye; Barbier, Bruno et al

in Field, Christopher; Jouzel, Jean; Le Treut, Hervé (Eds.) Our ender common climate future change, Abstract Book (2015, July 10)

This study assesses the impact of supplemental irrigation from small man-made basins on cereal production in climate variability and change context marked by dry spells in the Sahelian zone of Burkina ... [more ▼]

This study assesses the impact of supplemental irrigation from small man-made basins on cereal production in climate variability and change context marked by dry spells in the Sahelian zone of Burkina Faso. After two years, the experiments showed that this innovation in family farms increases maize yield and allows growing a second crop with the surplus of water available in the basin. At the end of the 2012-2013 campaign, the average maize yield was estimated 2.5 t/ha on experimental plots (EP) and 1.7 t/ha on control plots (CP). The average yield of the 2013-2014 campaign was evaluated as 3.3 T/ha and 0.9 t/ha for EP and CP respectively. Increase in yield is 0.8 t/ha for the 2012-2013 campaign and 2.4 t/ha during 2013-2014. It appears as well as the yield obtained on EP in 2012-2013 and 2013-2014 for bridging cereal need of 2 and 6 additional persons respectively in agricultural households compared to the CP. The review of the Net present value, Internal rate of return and the Net benefits increase ratio show that the profitability to practice supplemental irrigation depends on the types of basins. [less ▲]

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See detailModelling Uncertainties in Long-Term Predictions of Urban Growth: A Coupled Cellular Automata and Agent-Based Approach
El Saeid Mustafa, Ahmed Mohamed ULiege; Saadi, Ismaïl ULiege; Cools, Mario ULiege et al

in Ferreira, Joseph; Goodspeed, Robert (Eds.) Proceedings of CUPUM 2015 (2015, July 07)

Modelling the growth of urban settlements is of considerable interest for different applications, amongst which integrated flood management. This study aims at modelling urban growth for a long time ... [more ▼]

Modelling the growth of urban settlements is of considerable interest for different applications, amongst which integrated flood management. This study aims at modelling urban growth for a long time horizon up to 2100 and to integrate the model outcomes with a hydrological model for the same time horizon. Forecasting land-use change over such time frames entails very significant uncertainties. In this regard, the main focus of this paper is attributed to the handling of uncertainty in an urban growth model. To this end, we examine a Monte Carlo Simulation method, which is integrated in the proposed urban growth model. Transition probabilities for each non-urban cell are estimated by a coupled Cellular Automata-Agent-Based ap-proach. The results help to handle uncertainty over long time horizons and to assess the increment in degree of uncertainty at every time-step. [less ▲]

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See detailContribution du bilan de masse de surface antarctique à l’évolution du niveau des mers avec le modèle atmosphérique régional MAR
Agosta, Cécile ULiege; Fettweis, Xavier ULiege; Gallée, Hubert

in Actes du 28e colloque de l’Association Internationale de Climatologie (2015, July 02)

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See detailZonage phénoclimatique et caractérisation des parcours naturels du Sénégal avec les données de télédétection satellitaire
Diouf, Abdoul Aziz ULiege; Faye, G.; Minet, Julien ULiege et al

in XXVIIIème Colloque de l’Association Internationale de Climatologie, Liège 1-5 juillet 2015 (2015, July 02)

Les métriques phénologiques qui expriment certains événements du cycle de vie des plantes, tels que l'émergence, la croissance et la sénescence, principalement liées aux conditions météorologiques et au ... [more ▼]

Les métriques phénologiques qui expriment certains événements du cycle de vie des plantes, tels que l'émergence, la croissance et la sénescence, principalement liées aux conditions météorologiques et au climat, ont été utilisées afin : (i) de déterminer, à travers les parcours naturels du Sénégal, des entités "phénoclimatiques" homogènes ou phénorégions par classification non-supervisée des images de la série temporelle (1999-2013); (ii) d’analyser l’homogénéité des phénorégions en comparant l’évolution interannuelle de l’indice et des quantités de précipitation et (iii) de donner leurs principales caractéristiques biophysiques. Les résultats obtenus montrent que le domaine pastoral sénégalais peut être subdivisé en trois phénorégions à partir de la grande intégrale du NDVIS10 qui donne les entités spatiales les plus homogènes dans lesquelles les paramètres biophysiques comportent une variation latitudinale caractéristique du Sahel [less ▲]

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See detailLa 'ferronnerie de façade' degli edifici belgi dell¿ultimo ventennio del XIX secolo
Rapalo, Maria Chiara ULiege

in Atti del Convegno di Studi di Bressanone 30 giugno – 3 luglio 2015 (2015, July 02)

Le architetture belghe Art Nouveau hanno fornito l’occasione, nella seconda metà del XIX secolo, di assistere ad interessanti e innovative modalità di utilizzazione del ferro come elemento strutturale e ... [more ▼]

Le architetture belghe Art Nouveau hanno fornito l’occasione, nella seconda metà del XIX secolo, di assistere ad interessanti e innovative modalità di utilizzazione del ferro come elemento strutturale e ornamentale. L’impiego organico dello stesso con altri materiali, ha dato luogo, in quegli anni, a delle interessanti architetture che presentano singolari conformazioni di facciata, uniche nel loro genere. L’obiettivo del presente studio sarà quello di indagare sulle lavorazioni tradizionali del ferro, focalizzando in particolar modo l’attenzione sull’articolazione e sulla composizione degli infissi delle complesse facciate di alcuni edifici Art Nouveau, le quali hanno spesso avuto la capacità di creare significative e singolari connessioni tra il manufatto architettonico e l’ambiente naturale, il singolo edificio e il contesto urbano circostante. Infatti l’eleganza con cui il ferro in facciata è stato trattato come un filamento organico che si insinua nell’edificio - variandone le forme e diventando così corrimano, pilastro, apparecchio illuminante, bow window, portone, finestra e facendo in modo che questi da elementi applicati alla facciata, diventassero parte configurativa della facciata stessa - denota quanto il trattamento del materiale sia stato innovativo rispetto alla produzione architettonica realizzata fino a quell’epoca, influenzando anche le configurazioni dei luoghi e del contesto. Purtroppo, però, molto spesso gli interventi realizzati su alcuni edifici hanno modificato la composizione e la configurazione delle facciate, spesso compromettendo la presenza di elementi e materiali rappresentativi di tale epoca e corrente storica. Gli interventi hanno condotto talvolta a distruzioni massicce e rifacimenti spesso discutibili. Molte opere hanno subito cospicue manomissioni che, nell’intento di prolungarne la vita per adattarle alle esigenze della seconda metà del XX secolo, sono state completamente snaturate della loro essenza e della loro identità, mettendo in seria discussione la nota questione dell’autenticità. Si esamineranno, dunque, alcuni casi sotto questi aspetti significativi; in particolare saranno analizzate alcune rilevanti realizzazioni di Victor Horta e di altri protagonisti di un Belgio che viveva uno dei momenti più vivaci del proprio sviluppo culturale. [less ▲]

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See detailSuppression of simulated self-excited oscillation using smart materials on flexible wing structure
Abdul Razak, N.; Nasip, N. S.; Hawari, A. F. et al

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2015 (2015, July 01)

Suppression of simulated self-excited oscillation due to aeroelastic effects using piezoelectric patches is reported. The focus of the present work is suppressing simulated flutter oscillation using ... [more ▼]

Suppression of simulated self-excited oscillation due to aeroelastic effects using piezoelectric patches is reported. The focus of the present work is suppressing simulated flutter oscillation using piezoelectric patches bonded to the wing structure. First, a clean wing is exposed to airflow in the wind tunnel where it experienced limited amplitude oscillation. The responses were recorded. This is followed by bonding piezoelectric patches to the identical wing that was tested in the wind tunnel. Two of the patches were used as actuators to simulate self-excited oscillation in a control manner. The selected mode for excitation is 1st bending mode. The other two patches were used as suppressor for active control using negative velocity feedback Single-Input, Single-Output approach. The single input signal for negative feedback is also sensed using piezoelectric patches. The controller manages to suppress the simulated flutter response to a lower oscillation amplitude values. This works demonstrated the used of piezoelectric material as actuator to reproduce the oscillation amplitude during self-excited oscillation and suppress the oscillation at the same time. [less ▲]

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See detailPRELIMINARY ANALYSIS AND DESIGN OF AN EXPERIMENTAL FACILITY FOR THE PSEUDODYNAMIC EARTHQUAKE TEST OF A REAL SCALE STEEL MOMENT RESISTING FRAME WITH PARTIAL STRENGTH JOINT
Francavilla, Antonella Bianca ULiege; Latour, Massimo; Piluso, Vincenzo et al

in 8th International Conference on Behavior of Steel Structures in Seismic Areas Shanghai, China, July 1-3, 2015 (2015, July 01)

Last version of Eurocode 8 has introduced the possibility to employ partial strength joints in Moment Resisting Frames in seismic zone, provided that the connections are demonstrated to perform adequately ... [more ▼]

Last version of Eurocode 8 has introduced the possibility to employ partial strength joints in Moment Resisting Frames in seismic zone, provided that the connections are demonstrated to perform adequately under cyclic loadings. In this paper the preliminary analysis and the design of a Pseudodynamic (PsD) testing facility for the experimental study of a Real Scale two storeys-two bays steel MRF, with classical and innovative joint details, are showed. The preliminary Pushover and Incremental Dynamic Analyses carried out in Seismostruct software to estimate the forces and displacements expected at each storey for the selected ground motions have also been reported. The analysis are extended to all the different frame layouts that the research group intend to test and the main results obtained are presented. [less ▲]

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See detailA new test of uniformity for object orientations in astronomy
Pelgrims, Vincent ULiege

in Heavens, A. F.; Starck, J.-L.; Krone-Martins, A. (Eds.) Statistical Challenges in 21st Century Cosmology (2015, July 01)

We briefly present a new coordinate-invariant statistical test dedicated to the study of the orientations of transverse quantities of non-uniformly distributed sources on the celestial sphere. These ... [more ▼]

We briefly present a new coordinate-invariant statistical test dedicated to the study of the orientations of transverse quantities of non-uniformly distributed sources on the celestial sphere. These quantities can be projected spin-axes or polarization vectors of astronomical sources. [less ▲]

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See detailGaz à effet de serre indirects et qualité de l'air aux latitudes moyennes de l'hémisphère nord : tendances à long terme et variabilité déduites de télémesures effectuées au Jungfraujoch (Alpes suisses, 3580 m)
Franco, Bruno ULiege; Bader, Whitney ULiege; Lejeune, Bernard ULiege et al

in Erpicum, Michel (Ed.) Actes du XXVIIIe colloque annuel de l’Association Internationale de Climatologie : Modélisations et variabilités (2015, July 01)

Indirect greenhouse gases and air quality at Northern Hemisphere mid-latitudes: long-term trends and variability derived from ground-based remote sensing at Jungfraujoch (Swiss Alps, 3580 m a.s.l.). We ... [more ▼]

Indirect greenhouse gases and air quality at Northern Hemisphere mid-latitudes: long-term trends and variability derived from ground-based remote sensing at Jungfraujoch (Swiss Alps, 3580 m a.s.l.). We present an overview of recent investigations conducted by the Solar and Atmospheric Physics Infrared Group at the University of Liège and dedicated to the long-term monitoring of atmospheric gases with an indirect greenhouse effect and affecting air quality at Northern Hemisphere mid-latitudes. Gas concentrations are derived from high-resolution solar spectra recorded at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.), using Fourier transform infrared spectrometers. Time series obtained from these observations, along with satellite measurements and simulations from numerical models, allow for the study of both variability and recent evolution of these species and are critical for air quality monitoring and understanding climate changes. [less ▲]

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See detailMaking "Place" count in Risk perception studies
Ocampo, Lou Angeli ULiege; Schmitz, Serge ULiege

in Firmino, Ana (Ed.) Book of Abstracts and Programme: 23rd Annual Colloquium on Sustainable Rural Systems: Smart Answers for a smiling future (2015, July)

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See detailHybrid processing of SCADA and synchronized phasor measurements for tracking network state
Alcaide-Moreno, Boris; Fuerte-Esquivel, Claudio; Glavic, Mevludin ULiege et al

in Proc. IEEE PES General Meeting (2015, July)

This paper proposes a new tracking state estimator aimed at following some of the dynamics of the network state (bus voltage phasors) by a hybrid processing of SCADA and synchronized phasor measurements ... [more ▼]

This paper proposes a new tracking state estimator aimed at following some of the dynamics of the network state (bus voltage phasors) by a hybrid processing of SCADA and synchronized phasor measurements. The latter are assumed to be available in limited number. To avoid time skew effects, only the SCADA measurements received since the last execution of the estimator are processed. To ensure observability, estimated SCADA measurements are used as pseudo-measurements. The procedure includes a prediction, an innovation analysis and a correction step. The latter consists of solving a constrained least-squares optimization. The simulation results refer to a test system undergoing large disturbances, evolving to long-term voltage instability or stabilized by emergency control. The proposed method appears to satisfactorily track the overall network evolution, even during those severe conditions. [less ▲]

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See detailAre there different analysis paterns when people assess rural landscapes?
Vanderheyden, Vincent ULiege; Schmitz, Serge ULiege

in Firmino, Ana (Ed.) Book of Abstracts and Programme: 23rd Annual Colloquium on Sustainable Rural Systems: Smart Answers for a smiling future (2015, July)

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See detailEtude de l'évolution de l'enneigement dans les Hautes Fagnes (Belgique) au cours des cinquante dernières années à l'aide du modèle climatique régional MAR
Wyard, Coraline ULiege; Fettweis, Xavier ULiege; Erpicum, Michel ULiege

in Erpicum, Michel (Ed.) Actes du XXVIIIe colloque annuel de l’Association Internationale de Climatologie : Modélisations et variabilités (2015, July)

The “Modèle Atmosphérique Régionale” MAR is a regional climate model originally developed to study the polar ice sheets. In this study, the MAR model has been adapted to Belgium in order to study the snow ... [more ▼]

The “Modèle Atmosphérique Régionale” MAR is a regional climate model originally developed to study the polar ice sheets. In this study, the MAR model has been adapted to Belgium in order to study the snow cover evolution of the High Fens (east of Belgium), a region covered by snow on average one to two months per year. As validation, we have sucessfully compared MAR based daily snow heights with snowcam-based and/or laser sensor-based observations over the period 2008-2013. Then, the model has been forced by ERA-Interim since 1958 to study the snow cover evolution during the last fifty years at the summit of Belgium. The results show no significant trend despite global warming. [less ▲]

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See detailComparison of experimental results and numerical modelling of unreinforced load-bearing masonry structures subjected to earthquake loading
Mordant, Christophe ULiege; Denoël, Vincent ULiege; Degée, Hervé

in Proceedings of the SECED 2015 Conference: Earthquake Risk and Engineering towards a Resilient World (2015, July)

This paper presents a comparison of experimental tests results on unreinforced load-bearing masonry structures subjected to earthquake loading with numerical predictions. First, simple walls are submitted ... [more ▼]

This paper presents a comparison of experimental tests results on unreinforced load-bearing masonry structures subjected to earthquake loading with numerical predictions. First, simple walls are submitted to cyclic and shaking table tests. Some of them include soundproofing devices in order to investigate their influence on the general behaviour in static and dynamic conditions. Additional walls with an opening and T-shaped walls are then tested under cyclic loading. The study is focused on the frame effect, the contribution of the perpendicular wall to the global strength and the efficiency of the connection. These aspects are also studied through shaking table tests on two masonry frames with T- or L-shaped piers. The main information is expressed in terms of force-displacement curves, mechanical properties and energy dissipation for the cyclic tests. The shaking table tests provide results in terms of dynamic and mechanical properties. Comparison of the results with numerical predictions is finally performed thanks to the software TREMURI. [less ▲]

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See detailComparative study of different output metrics for a three weakly coupled resonator sensor
Zhao, Chun; Wood, Graham; Xie, J.B. et al

in Proceedings of Solid-State Sensors, Actuators and Microsystems (Transducers 2015) (2015, July)

This work, for the first time, investigates the characteristics of different output metrics for a three degree-of-freedom (DoF) coupled resonator sensor. The main aspects examined are sensitivity and ... [more ▼]

This work, for the first time, investigates the characteristics of different output metrics for a three degree-of-freedom (DoF) coupled resonator sensor. The main aspects examined are sensitivity and linear range. It is shown from electrical measurements that using the vibration amplitude ratio as an output signal provides improved sensitivity and linearity range, compared to other methods such as shift in eigenstate, mode frequency or amplitude difference. [less ▲]

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See detailMarcel-Henri Jaspar, "Le plus gaullien des Belges" ? Construction et déconstruction d'une réputation (1940-1966)
Genin, Vincent ULiege

in Lanneau, Catherine; Depagie, Francis (Eds.) De Gaulle et la Belgique (2015, July)

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See detailiPot: Industrial Potato monitoring for the Belgian potato sector using remote sensing and crop growth modelling
Wellens, Joost ULiege

in Qu, Dongyu (Ed.) Develop Together for a Better Future (2015 Beijing World Potato Congress) (2015, July)

The Belgian potato processing industry has known a spectacular growth during the last decades. The companies active in this sector (most of them family owned enterprises) have succeeded – together with ... [more ▼]

The Belgian potato processing industry has known a spectacular growth during the last decades. The companies active in this sector (most of them family owned enterprises) have succeeded – together with primary producers and traders – to grow from 500.000 tons of processed potatoes in 1990 till 3.650.000 tons of raw material in 2012. When considering the production (in tons) per habitant, Belgium is ranked on the 4th place with a production of 395 tons per 1.000 inhabitants. Nowhere in the world are higher yields obtained than in Belgium. To keep up its position on the forefront of innovation, the potato processing industries are continuously looking at promising novel technologies that could improve business processes at any stage of growth. The close follow up of parcels on the land as form above is becoming an important tool to improve the quantity and the quality of the potato crop, and reduce the risks in order to plan the storage, packaging or processing and as such to strengthen the competiveness of the Belgian potato in a global market. The iPot project, financed by the Belgian Science Policy Office (BELSPO), aims to provide the Belgian potato sector, represented by Belgapom, with near real time information on field condition (weather-soil) and crop development, and with early yield estimates, derived from a combination of satellite images and crop growth models. Satellite images are used since long for crop monitoring at regional level by the public sector. Traditionally, low to medium resolution images, with pixel sizes from 250m to 1km are used for providing information on crop growth and development, and on yield at regional scale. However, the recent launch of constellations of high resolution optical sensors (DMC, Sentinel-2) offering spatially detailed information (20m pixel size) at high frequency (every 2 to 3 days) and at low cost, is creating a (r)evolution in the world of crop monitoring. Automatic processing chains have been developed to derive vegetation indices (NDVI) and biophysical parameters (fAPAR, LAI, fCover). Maps are being derived on a regular basis with for each pixel the actual development stage of the potato crop. This on-line scanning of the growth (phenology) is expected to result in an increased performance of crop growth models and better yield predictions. Once the data for crop phenology are incorporated into the model (B-CGMS), the yield data collected at the parcel level will be assimilated into the model using optimization algorithms to minimize the discrepancies between observed and simulated yield time series in order to improve further yield estimations. The combination of these new earth observation and modelling techniques arose the interest of a new type of users, mainly from the private sector (agro-industry, agricultural insurers, etc.). The iPot project aims to bridge the gap between the latest research efforts regarding crop growth monitoring and the industry. An intuitive web based geo-information platform is being developed to allow both the Belgian potato industry and research centers to access, analyze and combine the data with their own field observations in closed collaboration with the farmers, for improved decision-making. [less ▲]

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See detailSketch-based and parametric modeling: Association of two-externalization processes for early daylight optimization
Gallas, Mohamed Anis ULiege; Delfosse, Vincent ULiege

(2015, July)

This paper focuses on sketch-based and parametric modeling as two externalization devices used in architectural design practice. The first part of this paper addresses features and ability of these ... [more ▼]

This paper focuses on sketch-based and parametric modeling as two externalization devices used in architectural design practice. The first part of this paper addresses features and ability of these externalization tools to support design activities during the early design steps. The second part proposes an association process of a sketch-based modeling tool (SketSha-Archi®) and a parametric modeling tool (Grasshopper®) to create an advanced process for daylight optimization. The process aimed to associate the hand-sketching freedom with the precise exploration functions of digital tools (parametric modeling and evaluation tools). [less ▲]

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See detailWe forgot to pay attention to ordinary tourism! A call to revise the research agenda for rural tourism
Schmitz, Serge ULiege; Crozat, Dominique

in Firmino, Ana (Ed.) Book of Abstracts and Programme: 23rd Annual Colloquium on Sustainable Rural Systems: Smart Answers for a smiling future (2015, July)

This paper aims to suggest a new research agenda for rural tourism, including for a smiling future for the countryside, in reversing the current trend to distinguish the destination, to aim at ... [more ▼]

This paper aims to suggest a new research agenda for rural tourism, including for a smiling future for the countryside, in reversing the current trend to distinguish the destination, to aim at supersegmentation of tourism and to target a cultural, elitist, tourism. Indeed most tourist activities can be done and are done in a relative vicinity, by ordinary tourists aiming to have a good time. Moreover, the countryside does not always offer extraordinary sights that attract people from the whole continent. We argue that there should be a place and more attention for ordinary tourism development. By ordinary tourism, we do not mean mass tourism but just the fact that some people spent a few days away from home. We do not want to reject the appealing concepts of cultural tourism, ecotourism, adventure tourism, ethnic tourism, gastronomic tourism, farm tourism and so on. We just want to be realistic and call to rethink the importance of ordinary tourism and its current challenges: facing new ways of traveling (e.g. Low cost), of buying vacation (e-commerce), of enjoying holidays (more frequently/with friends, alone or with the family/ being active or passive). [less ▲]

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See detailDynamic of agricultural innovations diffusion in Burkina Faso
Zongo, Bétéo ULiege; Diarra, Abdoulaye; Barbier, Bruno et al

in Field, Christopher; Jouzel, Jean; Le Treut, Hervé (Eds.) Our ender common climate future change, Abstract Book (2015, July)

This study highlights the factors determining the spread of agricultural innovations for water harvesting since the drastic effects of drought 70s in Burkina Faso. These innovations include zaï, stone ... [more ▼]

This study highlights the factors determining the spread of agricultural innovations for water harvesting since the drastic effects of drought 70s in Burkina Faso. These innovations include zaï, stone bunds, bunds land, half-moons, mulching and grass strips. A survey of 629 farmers revealed that farmers fall into five categories which are the pioneer, early, latecomer, late and non-adopters. After four decades of diffusion (1974-2013) the rate is estimated at 69.3% for stone bunds, 49.1% for zaï, 26.2% for grass strips and less than 10% for half-moons, bunds land and mulching. The multinomial logit model showed that the climatic conditions in the Sahel zone, age and perception of increased dry spells of farm households promoted the spread of these innovations. However, the low level of organization and access to agricultural services were the major constraints to their adoption. [less ▲]

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See detailSemi-empirical correlation to model heat losses along solar parabolic trough collectors
Dickes, Rémi ULiege; Lemort, Vincent ULiege; Quoilin, Sylvain ULiege

in Proceedings of ECOS 2015 (2015, July)

Solar thermal power plants convert sunshine energy into useful heat and electricity by means of solar collectors and a thermodynamic cycle. Among the different solar collector technologies, parabolic ... [more ▼]

Solar thermal power plants convert sunshine energy into useful heat and electricity by means of solar collectors and a thermodynamic cycle. Among the different solar collector technologies, parabolic troughs are nowadays the most widespread together with solar towers. In order to improve the computation speed required to simulate the temperature profile along solar parabolic trough collectors, a correlation estimating the effective heat losses of the receiver is an essential tool. However, the relations found in the literature lack accuracy and do not translate effectively the effects of the operating conditions in all cases. In this work, an alternative correlation is proposed and calibrated with the results of a deterministic model. Better fitting performance is demonstrated when compared to the prediction of the pre-existing correlations. The benefits and limitations of the new correlation are finally assessed. [less ▲]

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See detailModel reduction for simulating the dynamic behavior of parabolic troughs and a thermocline energy storage in a micro-solar power unit
Dickes, Rémi ULiege; Desideri, Adriano ULiege; Lemort, Vincent ULiege et al

in Proceedings of ECOS 2015 (2015, July)

Micro-scale concentrated solar power plants are characterized by strong transients and mostly operate in off-design working conditions. Both the sizing and the control of these systems are key challenges ... [more ▼]

Micro-scale concentrated solar power plants are characterized by strong transients and mostly operate in off-design working conditions. Both the sizing and the control of these systems are key challenges whose optimization requires powerful dynamic modeling tools. In this context, a system featuring a solar field of parabolic troughs, a thermocline thermal energy storage and a 5kWe organic Rankine cycle (ORC) power unit is modeled in the Modelica language. Model reduction methods applied to the solar field and the thermal storage are investigated and analyzed to improve the computational efficiency of the problem. Each model is described and integrated in the open-source ThermoCycle library. Results of simulation under identical operating conditions are compared and the benefits and limitations of model reduction are assessed. [less ▲]

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See detailOn Monotonicity and Propagation of Order Properties
Sootla, Aivar ULiege

in Proceedings of the American Control Conference (2015, July)

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See detailShaping Pulses to Control Bistable Biological Systems.
Sootla, Aivar ULiege; Oyarzun, Diego; Angeli, David et al

in In Proceedings of the American Control Conference. (2015, July)

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See detailMODIFYING PHYSICAL ENVIRONMENT TO BE APPROPRIATE FOR CHILDREN
Jidovtseff, Boris ULiege; Delvaux, Anne ULiege; Mornard, Manhattan ULiege

in Book of abstracts AISEP 2015 (2015, July)

Our experience confirms that adapting physical environments is critical for providing appropriate physical activity for 3 to 8 years old children.. Moreover, the pedagogy has to favour success, discovery ... [more ▼]

Our experience confirms that adapting physical environments is critical for providing appropriate physical activity for 3 to 8 years old children.. Moreover, the pedagogy has to favour success, discovery and a fun environment. This work illustrates what can be achieved and provides clear guidance for developing centres to support the promotion of physical activity in early childhood. [less ▲]

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See detailA Bayesian model for the Ebola epidemic in Sierra Leone
Frasso, Gianluca ULiege; Lambert, Philippe ULiege; Bonou, Wilfried ULiege

in Friedl, Herwig; Wagner, Helga (Eds.) 30th International Workshop on Statistical Modelling, Linz, Austria, 2015, Proceedings (2015, July)

We propose a Bayesian model for the analysis of the 2014 ebola out- break in Sierra Leone. It is based on an extension of the popular compartmental SEIR model speci ed using a system of di erential ... [more ▼]

We propose a Bayesian model for the analysis of the 2014 ebola out- break in Sierra Leone. It is based on an extension of the popular compartmental SEIR model speci ed using a system of di erential equations. [less ▲]

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See detailTentatives de prétraitement des granulats recyclés pour l’amélioration des bétons préfabriqués
Zhao, Zengfeng ULiege; Courard, Luc ULiege; Remond, Sébastien et al

in Ciments, bétons et fibres - Matériaux et structures (2015, July)

De très grandes quantités de déchets de construction et de démolition sont produites chaque année. Jusqu'à présent, seule une petite fraction de ces déchets de béton est réutilisée sous forme de granulats ... [more ▼]

De très grandes quantités de déchets de construction et de démolition sont produites chaque année. Jusqu'à présent, seule une petite fraction de ces déchets de béton est réutilisée sous forme de granulats pour la fabrication de béton. Afin de faire bon usage des granulats recyclés (GR) dans le béton, il est très important d’améliorer leurs propriétés. Dans cette étude, une méthode de traitement des GR au moyen d’une carbonatation accélérée en laboratoire et des méthodes de traitement par modification de l’état de surface des GR ont été étudiées. Les résultats montrent qu'après la carbonatation accélérée au laboratoire, la teneur en pâte de ciment durcie des GR mesurée par dissolution de l'acide salicylique diminue, que la densité et la surface spécifique des GR augmentent et que la porosité des GR diminue, ce qui conduit à la réduction de l'absorption d'eau des GR. Des agents hydrofuges à base de silane ont également été étudiés et semblent diminuer l’absorption d’eau par les GR. [less ▲]

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See detailBilevel optimization in the context of intermodal pricing: state of art
Tawfik, Christine Maher Fouad ULiege; Limbourg, Sabine ULiege

in Proceedings of the 18th Euro Working Group on Transportation, EWGT 2015 (2015, July)

With the rising interest to stimulate intermodal transport, determining pricing strategies can be intrinsically challenging. We provide a review on the current state of research in intermodal pricing ... [more ▼]

With the rising interest to stimulate intermodal transport, determining pricing strategies can be intrinsically challenging. We provide a review on the current state of research in intermodal pricing, through which we identify a peculiar gap in optimization approaches. A suggestion to exploit the bilevel optimization technique is presented, as well as an account of its widely successful application to price setting problems. The different approaches to express the network users’ behavior, regarded as the lower level problem, are highlighted together with the particular modeling aspects of intermodal networks. [less ▲]

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See detailPower Processing Unit Activities at Thales Alenia Space Belgium
Bourguignon, Eric; Defise, Jean-Marc ULiege; Fraselle, Stéphane

in Proceedings of the 34th International Electric Propulsion Conference, 4-10 July 2015 (2015, July)

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See detailIntégration de tablettes numériques dans la formation des futurs enseignants: une étude de cas
Parlascino, Emmanuelle ULiege; Joris, Noémie ULiege

in Karsenti, Thierry (Ed.) Mieux former les enseignants dans la francophonie: principaux enjeux actuels et futurs (2015, July)

À travers cette recherche, les auteurs visent à mettre en évidence, chez les étudiants, les apports réels, en termes d’apprentissages et de développement professionnel, de situations d’enseignement ... [more ▼]

À travers cette recherche, les auteurs visent à mettre en évidence, chez les étudiants, les apports réels, en termes d’apprentissages et de développement professionnel, de situations d’enseignement intégrant une technologie, à savoir les tablettes numériques. Le groupe d’étude se constitue d’un enseignant en histoire en haute école pédagogique et de trois classes d’étudiants en formation pour devenir enseignants. Ce groupe fera l’objet d’une analyse approfondie au travers d’observations filmées, examinées à l’aide de grilles, et de commentaires réflexifs (de l’enseignant et des étudiants) issus d’entretiens d’autoconfrontation sur divers extraits des situations d’enseignement menées et vécues. Cette méthodologie conduira à croiser plusieurs types d’informations : (1) les objectifs de l’enseignant au moment de préparer la situation d’enseignement, (2) sa perception des apports mis en place à travers la technologie, (3) la perception de ses étudiants et (4) les observations des auteurs. Soucieux de contribuer à l’analyse réflexive sur l’intérêt d’intégrer le numérique en éducation, les auteurs veulent mettre en évidence les apports réels de l’activité, les points de passage obligés et les principales difficultés de sa mise en place. Ces résultats pourront éclairer les enseignants souhaitant se lancer dans ce genre d’activité innovante. [less ▲]

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See detailAnalysis of submesoscale eddies in the Baltic Sea based on SAR imagery and model wind data
Karimova, Svetlana ULiege; Gade, Martin

in Proc. IGARSS 2015 (2015, July)

We discuss the spatio-temporal distribution of sub-mesoscale eddies seen in synthetic aperture radar (SAR) imagery of the Baltic Sea. Analyzing about 1250 Envisat Advanced SAR (ASAR) images acquired ... [more ▼]

We discuss the spatio-temporal distribution of sub-mesoscale eddies seen in synthetic aperture radar (SAR) imagery of the Baltic Sea. Analyzing about 1250 Envisat Advanced SAR (ASAR) images acquired between 2009 and 2011 almost 7000 sub-mesoscale eddies were discovered. Since the visibility of vortical structures in SAR imagery significantly depends on the near-surface wind speed, wind data from a numerical model of the Baltic Sea were additionally used to improve our eddy statistics. Within the method proposed herein only those parts of SAR images are considered for the calculation of eddy statistics, which were acquired when the wind speed conditions were favorable for eddy manifestations. As a result, and despite the fact that eddies were generally observed all over the Baltic Sea, we show that the south-western part of the Baltic Sea seems to have especially high sub-mesoscale eddy activity. [less ▲]

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See detailAsymmetric limit cycle oscillations in systems with symmetric freeplay
Dimitriadis, Grigorios ULiege

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2015 (2015, June 30)

In this paper, a simple 2D aeroelastic system with degrees of freedom in pitch, plunge and control surface deflection is investigated with freeplay in the pitch degree of freedom. It is shown that this ... [more ▼]

In this paper, a simple 2D aeroelastic system with degrees of freedom in pitch, plunge and control surface deflection is investigated with freeplay in the pitch degree of freedom. It is shown that this system features a fixed point at the origin as well as two anti-symmetric fixed points. Asymmetric limit cycles that span only two of the three piecewise linear subdomains of the phase plane can orbit these anti-symmetric fixed points. A single three-domain symmetric cycle and two two-domain cycles appear as a result of a grazing bifurcation occurring at the flutter speed of the underlying linear system. The two-domain cycles can undergo further fold, period doubling and torus bifurcations. They can cause both periodic and aperiodic oscillations, including highly chaotic responses at parameter values where they interact strongly. [less ▲]

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See detailUsing 2D-PIV measurements to compute unsteady aerodynamic loads on a flat plate at high angle of attack
Guissart, Amandine ULiege; Bernal, Luis; Dimitriadis, Grigorios ULiege et al

in Proceedings of the 16th International Forum on Aeroelasticity and Structural Dynamics, IFASD 2015 (2015, June 30)

This work exposes and discusses results obtained for aerodynamic forces using an indirect calculation based on Particle Image Velocimetry (PIV) measurements. The methodology used is based on the integral ... [more ▼]

This work exposes and discusses results obtained for aerodynamic forces using an indirect calculation based on Particle Image Velocimetry (PIV) measurements. The methodology used is based on the integral formulation of the Navier-Stokes equations and is applied to spatio-temporal data for different flows around a plate with a 16:1 chord-to-thickness ratio at high angle of attack. Experimental data are obtained in a water channel for both a static and a pitching plate. In addition to PIV data, direct measurements of aerodynamic loads are carried out to assess the quality of the indirect calculation. It is demonstrated that this indirect method is able to compute the mean and the temporal evolution of the lift and drag coefficients with a reasonable accuracy. It is also shown that the noise sensitivity of the method can be partly alleviated through the use of Dynamic Mode Decomposition (DMD) as a pre-processing step to smooth the spatio-temporal data. [less ▲]

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See detailUnsteady Viscous-Inviscid Coupling Simulations of Separated Laminar Flows Around 2D Airfoils
Rothkegel Ide, José Ignacio ULiege; Dimitriadis, Grigorios ULiege

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2015 (2015, June 29)

An interactive boundary layer model has been developed in 2D in order to solve the unsteady flow around an airfoil. The inviscid problem is solved using a panel method, by the discretization of the ... [more ▼]

An interactive boundary layer model has been developed in 2D in order to solve the unsteady flow around an airfoil. The inviscid problem is solved using a panel method, by the discretization of the airfoil into linear-varying vortex panels. The solution of the boundary layer equations is carried out using a finite volume scheme. Viscous-inviscid coupling is preformed by imposing a permeation velocity on the skin panels of the airfoil and the addition of a free wake at each separation point. [less ▲]

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See detailA comparative study for simulation of heat transport in large district heating network
Sartor, Kevin ULiege; Thomas, David ULiege; Dewallef, Pierre ULiege

in Proceedings of ECOS 2015 (2015, June 29)

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See detailTheoretical and experimental investigation of a structurally and aerodynamically nonlinear pitch and flap wing
Verstraelen, Edouard ULiege; Boutet, Johan ULiege; Grappasonni, Chiara ULiege et al

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2015 (2015, June 29)

This paper presents and experimental and theoretical investigation of a novel nonlinear aeroelastic system. It consists of a wing with pitch and flap degrees of freedom, suspended from a leaf spring ... [more ▼]

This paper presents and experimental and theoretical investigation of a novel nonlinear aeroelastic system. It consists of a wing with pitch and flap degrees of freedom, suspended from a leaf spring secured in a nonlinear clamp. Both the structural and the aerodynamic forces acting on the wing can be nonlinear, depending on the amplitude of oscillations. Wind tunnel experiments show that the system undergoes a supercritical Hopf bifurcation that leads to small amplitude limit cycle oscillations. At a particular airspeed, the pitch amplitude jumps to a much higher value and dynamic stall starts to occur. Three mathematical models of the system are formulated, one based on linear aerodynamics and two based on the Leishman-Beddoes dynamic stall model. The objective of the modelling is to determine whether the jump in pitch oscillation amplitude is due to dynamic stall. The predictions for amplitude, frequency and mean angle of the limit cycle oscillations are compared to the experimental observations. All three models predict the small amplitude oscillations with satisfactory accuracy. The complete Leishman-Beddoes model predicts the occurrence of a jump in pitch amplitude but the magnitude of this jump is signi cantly overestimated. The other two models completely fail to model the jump. The failure of the Leishman-Beddoes model to predict the correct post-jump oscillation amplitude may be due to the values selected for the model parameters. [less ▲]

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See detailDéveloppement et analyse d’un modèle in vitro d’infection épidermique par dermatophytes anthropophiles
Faway, E; Cambier, Ludivine ULiege; Lambert de Rouvroit, C et al

in Proceedings du 33e Congrès Annuel de Recherche Dermatologique (CARD) (2015, June 25)

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See detailOverview and recommendation on urban densification potential in Liège, Belgium
Attia, Shady ULiege

in AEE INTEC (Ed.) High-quality retrofit and redensification with timber construction systems (2015, June 18)

Belgium, like many European Countries, has a serious challenge in the housing sector. The Federal planning bureau estimates the increase of population by one million inhabitants by 2030, which represent ... [more ▼]

Belgium, like many European Countries, has a serious challenge in the housing sector. The Federal planning bureau estimates the increase of population by one million inhabitants by 2030, which represent 600.000 additional family requiring accesses to new housing facilities. Population ageing (mainly due to increasing life expectancy) combined with a constant growing rate of individuals living in collective households, leads to a substantial increase of demand of collective households (Vandresse & Bureau, 2013). This highlights a substantial challenge underlined mainly in the need to live in cities, which as consequence will increase the demand for smaller housing with or without integrated services or equipment in common. Furthermore, the stringent European performance environmental regulations for the building sector require that by 2020, all new construction are zero or nearly zero energy, (equivalent to 15 kWh/m2/year), with 60% efficient on-site coverage by renewable energy. The shortage of vacant land and the increasing energy performance requirements is pushing the idea of urban densification and zero energy construction households. During the recent 6 years, there has been a trend to use timber frame constructions as a sustainable solution facing the economic and environmental crisis in Belgium. However, there is lack of knowledge on the design, construction and operation of zero energy lightweight constructions for urban densification. The goal of this research is to provide an overview and recommendation on urban densification potential in Liège Province. The focused aim is to demonstrate validated design prototypes and products of different zero energy, timber frame construction systems and composite components. Thus inform and support the decision making of policy makers, municipalities, developers, and architects and building engineers in Belgium. [less ▲]

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See detailScreening and analyzing retrofit systems for zero energy renovation and their potential application in Liège, Belgium
Attia, Shady ULiege

in AEE INTEC (Ed.) High-quality retrofit and redensification with timber construction systems (2015, June 18)

Retrofit systems for Zero Energy Renovation comes energy as the most topical subject in the Belgian construction sector. Concepts and solutions for zero energy renovation are a new topic. Since 2006 ... [more ▼]

Retrofit systems for Zero Energy Renovation comes energy as the most topical subject in the Belgian construction sector. Concepts and solutions for zero energy renovation are a new topic. Since 2006, Belgium has been striving to achieve the European ambitions of fulfilling the Kyoto Protocol by insulating more effectively and reducing CO2 emissions associated with the use of fossil fuel for operational and embodied energy in buildings. In 2011, a Belgian decree mandated the construction of nearly zero and nets zero energy buildings by 2020. Following the German PassivHaus Standard performance requirements the Belgian residential sector is aiming to achieve an energy consumption to less than 15 kWh/m2/year and an onsite renewable energy production up to 60% for every newly construct household. In this, context the study will build on grounded knowledge developed and implemented by the IEA ECBCS Annex 50: Prefabricated Systems for Low Energy Renovation of Residential Buildings. The goal of this research is to screen and select a series of envelope retrofitting solutions. The focused aim is to demonstrate validated envelope prototypes and products of different zero energy, timber frame construction systems and composite components. This will include the comparison of timber retrofit systems with conventional systems. Thus inform and support the decision making of policy makers, municipalities, developers, and architects and building engineers in Belgium. [less ▲]

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See detailWood, the material of tomorrow's retrofits
Ruellan, Guirec ULiege; Attia, Shady ULiege

in High-quality retrofit and redensification with timber construction systems (2015, June 18)

The construction sector has focused for many years on performance improvement of new constructions. Today's largest problem is the energetic retrofitting of existing buildings. The building retrofit is an ... [more ▼]

The construction sector has focused for many years on performance improvement of new constructions. Today's largest problem is the energetic retrofitting of existing buildings. The building retrofit is an important strategy for energy savings. Building retrofit is addressed towards the real estate in Europe and allows for substantial gains, especially for heating houses and urban densification. However retrofit requires the use of special construction techniques. The problem is quite different from that of the new buildings: adaptation to existing building, heritage conservation, elimination of thermal bridges, etc. In this context, wood is experiencing strong growth in its use in new constructions, due to its qualities. And we think that some of those allow more appropriate responses to retrofit than other traditional materials. In this study, we will first present succinctly the problems related to the renovation, then we will dedicate ourselves to define the characteristics of the wood. The focus will be on some problems that commonly arise in wood constructions. We will then discuss a case, highlighting different characteristics of wood that are particularly important in this particular renovation. This allows us to observe on the ground the coherence of the choice of wood in the renovation. A discussion will close the study by summarizing the advantages and limitations of the use of wood in the renovation This is not to show that wood is one of the most environmentally friendly building materials, or demonstrate the sustainable character of retrofit. This is to see that the timber construction systems can provide an adequate response to many retrofit issues. [less ▲]

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See detailCompétition partisane, changement climatique et écologie politique : convergences et conflits sur les thématiques politiques
Piet, Grégory ULiege

in Flipo, Fabrice (Ed.) Les actes du Colloque "Penser l'écologie politique" (2015, June 16)

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See detailEVALUATION OF CONTINUOUS SUPRASCAPULAR NERVE BLOCKADE IN THE TREATMENT OF REFRACTORY ADHESIVE CAPSULITIS : A RETROSPECTIVE STUDY
MUTSERS, Pierre ULiege; LECOQ, Jean-Pierre ULiege; GOFFIN, Pierre ULiege et al

in Abstract Book du Residence Meeting de la Société Belge d'Anesthésie (2015, June 15)

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See detailIs it possible for large herds to graze while keeping a high milk yield level? The experience of two Belgian dairy farms.
Lessire, Françoise ULiege; Hornick, Jean-Luc ULiege; Dufrasne, Isabelle ULiege

in van den Pol-van Dasselaer, Agnes; Aarts, H.F.M; De Vliegher, Alex (Eds.) et al Grassland and forages in high output dairy farming systems (2015, June 15)

Grazing is more and more abandoned because of increasing size of herds and automation of herd management (e.g. automatic milking system – AMS). In this context, this study aims to evaluate milk production ... [more ▼]

Grazing is more and more abandoned because of increasing size of herds and automation of herd management (e.g. automatic milking system – AMS). In this context, this study aims to evaluate milk production and composition of 2 large Belgian dairy herds equipped with AMS during winter and summer. These herds were followed over 2 years. At grazing, 30% of the offered feed was grass. Milk production in both herds was similar in summer and winter (30.2 ± 7.14 vs 29.7 ± 7.8 ± in Herd 1 and 26.9 ± 0.8 vs 26.4 ± 0.8 in Herd 2) while their milk composition differed. In conclusion, it is possible for grazing to be preserved even in large herds without impacting noticeably on the herd performance. [less ▲]

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See detailRegional crop and irrigation monitoring: some examples of (new) opportunities
Wellens, Joost ULiege

in Begian workshop: Space4Food (2015, June 11)

Satellite images are used since long for agricultural monitoring at different spatial scales: from continental, national to regional and even field level. Combined with agro-meteorological data and ... [more ▼]

Satellite images are used since long for agricultural monitoring at different spatial scales: from continental, national to regional and even field level. Combined with agro-meteorological data and simulation models they constitute powerful decision support tools for agriculture throughout the world. Some examples at different scales and domains are presented. In Burkina Faso, free MODIS time series of coarse resolution vegetation indices (NDVI), phenological and meteorological data are combined in a multiple regression analysis for early yield warning in the cotton industry. Using a limited amount of data, it allows a decent yield forecasting more than a month before harvest. Time series of ERS radar images are analysed to monitor water intakes on the irrigated perimeter of Tadla (Morocco). The back-scatter intensity gives a clear indication of the top soil moisture state, permitting irrigation managers a regional monitoring of the irrigation water distribution and a guidance in the water allocation pricing. Actually in Belgium, and soon to be exported elsewhere, very-high resolution imagery (SPOT-5 Take5) are used to observe crop canopy development (fAPAR, fCover) on field level. Either by curve-fitting functions or assimilating these satellite derived data in existing crop growth models, improved and spatially more detailed forecasting systems are being developed. Although mostly still in the domain of applied research, the new availability of high spatial and temporal resolution imageries such those that will provide the Sentinel satellites paves the way to a growing number of operational end users. [less ▲]

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See detailChronic Toxic Hepatitis in Beef Calves due to Mycotoxins in Mixed Feed
Theron, Léonard ULiege; Callebaut, Alfons; Bayrou, Calixte ULiege et al

in Zemljic, Borut; Podpecan, Ozbalt; Zmljic-Jokhadar, Spela (Eds.) Proceedings of the XV middle European Buiatric Congress (2015, June 10)

Mycotoxins intoxination is an emerging disorder in Belgium, due to evolution of cultural practices and harvesting weather conditions. These intoxinations are difficult to diagnose for the vet practioners ... [more ▼]

Mycotoxins intoxination is an emerging disorder in Belgium, due to evolution of cultural practices and harvesting weather conditions. These intoxinations are difficult to diagnose for the vet practioners, since unspecific clinical signs, and their impact on ruminant disorder remains controversial. Although legal concentrations have been established for mycotoxins in the EU, farm forages are most of the time not tested (EU 2006/576/EC). In January 2015, a 500 calvings cross-bred Belgian blue cattle herd (BVDV free) referred a second (the first was directly sent to the rendering-plant) unexplained fatal case of jaundice on a 2 months-old calf to the Clinic for Ruminants of the University of Liège for necropsy. In 2013, a case of jaundice due to a Salmonella dublin hepatocholecystitis had previously diagnosed in this farm (Ronzoni et al., 2014), but so far preventions measures were implemented. Necropsy revealed generalized icterus, mild bilirubinuria, splenomegaly, but no precise etiology. On February a second 2 month old calf with jaundice is referred, lethargic, normothermic with a mild diarrhea, Calf shown generalized jaundice, anemia, elevation of leukocytes (neutrophils, eosinophils and monocytes), TGO, bilirubinemia, total biliary acids and Globulins (alpha2). He had also diminished erythrocytes and albuminemia. Copraemia, leptospirosis serology, leademia, hemoculture and pancreatic enzymes were within normal ranges, ruling out classic causes of jaundice in calf. Abdomen ultrasonography revealed a mild hyperechogenicity of the liver but no gall bladder modifications. Symptomatic treatment was based on symptoms, with fluidotherapy and choleretics. A third calf was referred three days after in a worst clinical condition, with also a severely modified liver enzymes, but no anemia. Three days after, this calf died and a necropsy revealed petechiae and hemorrhages in the abomasum, congestive mucosae in the distal bowel, white depot in the kidney medulla, modified urine and splenomegaly. Bile bacteriology and leptospirosis PCR was negative and liver histopathology revealed a severe histopathological liver degeneration associated with a disruption of the parenchyma and marked hyperplasia of the bile ducts compatible with chronic metabolic disorder. Meanwhile, the anemic calf recovered from anemia without any treatment after 4 days and was discharged from the Clinic for Ruminants. Considering the weird clinical patterns of these jaundice cases, and the fact that only calves from 2 to 3 months were affected, a nutritional origin as etiology was suspected. To test it, eight clinically healthy two to three months-old calves, of two different pens were sampled. TGO, GLDH, GGT or biliary acids were either modified and the values tended to increase with the age of the calves. The water was analyzed for classic toxics, and cultured for total germ content and everything were within recommended values. The calves fed with a milk replacer (30 % milk powder), and a commercial calf starter until one month of age. Then, they were given a mixed feed (containing cereal mix, cocoa, beet pulp, soja, maize), made at the farm from primary product/byproducts bought from different sources. The mix was tested for mycotoxins presence and ranged from 0.8 to 1.5 ppm of Desoxynivalenone (DON), and 115-215 ppb of Zearalenone (ZEA). The principal source of DON was maize (3.1 to 6.2 ppm), as for ZEA (0.3-0.6 ppm), but several compounds contained small dose of DON (0.2-0.7 ppm) for Barley feed, Tanned soja. Cacao contained 2.7 to 5.9 ppb of Ochratoxine (OTA). Nutritionnal recommendations were immediately given with a change in the source of maize and an addition of clay and yeast at 40g/calf/day and hay. Since, any other hypothetic origin to this progressive hepatic intoxination was demostrated, and that the doses founded, even if barely legal in the mix, are not accounted for toxic in the EU regulation, we believe that the calves were chronically exposed to these toxins. However, some mycotoxins experts still claim that various clinical signs would be observed in ruminants, if the rumen is partially defaunated, like in our case with the lake of forage. We propose that monitoring of subclinical liver health could be a key to screen DON effects. [less ▲]

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See detailQuelques écueils à éviter lors de la rédaction et la publication d'un règlement-taxe
Bortolotti, Aurélien ULiege

in Le droit communal - Etat des lieux (2015, June 05)

La présente contribution a pour seule ambition d’énoncer et d’expliquer les écueils à éviter lors de la rédaction et de la publication d'un règlement-taxe. Il ne sera, par conséquent, pas question de ... [more ▼]

La présente contribution a pour seule ambition d’énoncer et d’expliquer les écueils à éviter lors de la rédaction et de la publication d'un règlement-taxe. Il ne sera, par conséquent, pas question de rappeler les principes généraux en la matière, mais au contraire d’envisager les problèmes récurrents soulevés devant les juridictions administratives et judiciaires. Nous analyserons successivement la motivation du règlement-taxe, sa rétroactivité, sa publication ainsi que le respect de la procédure de taxation d’office. Ensuite, nous examinerons la procédure de contestation de ces impôts. Nous rappellerons, à cette occasion, le délai pour introduire une réclamation administrative, mais également la représentation de l’autorité locale devant les instances judiciaires. Nous clôturerons notre analyse par la question de l’indemnité de procédure et plus particulièrement les questions préjudicielles récemment posées par le tribunal de première instance d’Arlon à la Cour constitutionnelle. Ce domaine n’échappant pas à la régionalisation des compétences, il convient préalablement d’envisager la manière dont les différents législateurs régionaux réglementent les principes applicables à ces perceptions tout en conservant à l’esprit que la loi du 24 décembre 1996 relative à l'établissement et au recouvrement des taxes provinciales et communales reste la colonne vertébrale de ces réformes. [less ▲]

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See detailModélisation de la remontée des eaux dans les anciennes mines de charbon : un outil pour détecter les seuils de risques d’inondation en plaine alluviale de la Meuse près de Liège (Belgique)
Dassargues, Alain ULiege; Wildemeersch, Samuel; Orban, Philippe ULiege et al

in Des villes et des territoires sobres et sûrs, Synthèse des interventions (2015, June 03)

La plaine alluviale de la Meuse occupe la partie centrale du bassin charbonnier de Liège. Durant les exploitations minières, les niveaux d’eau des aquifères avaient été rabattus par des pompages d’exhaure ... [more ▼]

La plaine alluviale de la Meuse occupe la partie centrale du bassin charbonnier de Liège. Durant les exploitations minières, les niveaux d’eau des aquifères avaient été rabattus par des pompages d’exhaure. Des galeries d’exhaure creusées à partir des pieds de versant dans la vallée de la Meuse contribuaient également à dénoyer le gisement. La fermeture des dernières exploitations minières durant les années 70 et 80 a été le plus souvent assortie d’un arrêt des opérations de pompage qui y sont associées. Ceci a induit une remontée significative des eaux souterraines avec des conséquences indésirables possibles. Les modèles hydrogéologiques peuvent grandement aider à simuler les écoulements des eaux souterraines dans le contexte particulier des travaux miniers. Cependant, les techniques de modélisation classiques ne sont pas adaptées à ce contexte car le milieu est fortement perturbé par les anciens travaux et les réseaux de galeries. Par conséquent, des techniques de modélisation spécifiques ont été développées. Il s'agit d'une combinaison de modèles de boîte (ne nécessitant que quelques paramètres) pour calculer les niveaux d'eau moyens dans les zones exploitées, avec une modélisation physiquement basée et spatialement distribuée représentant explicitement les zones inexploitées et prenant en compte les interactions entre ces deux sous-domaines. Grâce à ce couplage, les échanges d'eau entre les zones exploitées et inexploitées sont explicitement pris en compte. La méthode permet de simuler la remontée des eaux souterraines après la fermeture des mines et des phénomènes associés tels que les 'coups d'eau' produits par les galeries drainantes. Les concepts et équations de la méthode sont présentés et illustrés sur des cas synthétiques, puis sur l'application de la zone de Cheratte-Blégny. [less ▲]

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See detailImpact des changements climatiques sur la principale réserve en eau souterraine alimentant la ville de Liège (Belgique)
Goderniaux, Pascal; Orban, Philippe ULiege; Compère, Jean-Michel et al

in Des villes et des territoires sobres et sûrs, Synthèse des interventions (2015, June 02)

Le changement climatique amène de nouvelles 'pressions' sur les ressources en eaux de surface et souterraines dans de nombreuses zones du monde. Des travaux scientifiques sont nécessaires pour aider les ... [more ▼]

Le changement climatique amène de nouvelles 'pressions' sur les ressources en eaux de surface et souterraines dans de nombreuses zones du monde. Des travaux scientifiques sont nécessaires pour aider les gestionnaires de l'eau à planifier les changements futurs. Un générateur de climats transitoire sophistiqué est utilisé en combinaison avec une modélisation intégrée hydrologique (HydroGeoSphere) pour évaluer les impacts sur les ressources en eaux souterraines de façon probabiliste. Cette nouvelle méthodologie est appliquée pour l'aquifère crayeux de Hesbaye (bassin Geer en Belgique) qui est le principal réservoir d'eau souterraine pour l'alimentation de la ville de Liège. Les sources d'incertitude étudiées sont les suivantes: (1) l'incertitude liée à la calibration du modèle hydrologique, en utilisant 'UCODE_2005'; (2) l'incertitude liée aux modèles climatiques mondiaux et régionaux (GCM et RCM); (3) l'incertitude liée à la variabilité naturelle du climat, en utilisant des scénarios stochastiques de changement climatique locaux. 100 changements climatiques équiprobables scénarios ont été générés sur 2010-2085 pour chacun des six RMC différents. Les résultats montrent que bien que les intervalles de confiance à 95% calculés autour des niveaux piézométriques calculés restent importants, l'effet du changement climatique devient clair et plus prononcé que la variabilité naturelle du climat d'ici 2085. Cette méthodologie constitue une réelle amélioration dans le domaine des prévisions de l'évolution des réserves en eau souterraine dans des conditions de changement climatique car il permet aux gestionnaires d'analyser les risques et prendre des décisions en toute connaissance du degré de confiance des résultats. [less ▲]

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See detailRegression-based modelling of a fleet of gas turbine engines for performance trending
Borguet, Sébastien ULiege; Léonard, Olivier ULiege; Dewallef, Pierre ULiege

in Proceedings of ASME Turbo Expo 2015 (2015, June)

Module performance analysis is a well-established framework to assess changes in the health condition of the components of the engine gas-path. The primary material of the technique is the so-called ... [more ▼]

Module performance analysis is a well-established framework to assess changes in the health condition of the components of the engine gas-path. The primary material of the technique is the so-called vector of residuals, which are built as the difference between actual measurement taken in the gas-path and values predicted by means of an engine model. Obviously, the quality of the assessment of the engine condition depends strongly on the accuracy of the engine model. The present paper proposes a new approach for data-driven modelling of a fleet of engines of a given type. Such black-box models can be designed by operators such as airlines and thirdparty companies. The fleet-wide modelling process is formulated as a regression problem that provides a dedicated model for each engine in the fleet, while recognising that all engines are of the same type. The methodology is applied to a virtual fleet of engines generated within the ProDiMES environment. The set of models is assessed quantitatively through the coefficient of determination and is further used to perform anomaly detection. [less ▲]

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See detailDesign Sensitivity Analysis for Shape Optimization of Nonlinear Magnetostatic Systems
Kuci, Erin ULiege; Duysinx, Pierre ULiege; Dular, Patrick ULiege et al

in Proceedings of COMPUMAG 2015 (2015, June)

In this paper, a direct and an adjoint analytic sensitivity analysis for a nonlinear magnetostatic system is obtained, in the context of shape optimization for any design function. The calculations are ... [more ▼]

In this paper, a direct and an adjoint analytic sensitivity analysis for a nonlinear magnetostatic system is obtained, in the context of shape optimization for any design function. The calculations are based on the material derivative concept of continuum mechanics. The resulting sensitivity formula can be expressed as either a volume integral or as a boundary integral along the interface where shape modification occurs. A method for the calculation of the design velocity field and mesh updating scheme is introduced as well. The accuracy of the methodology is analysed on an inductor system, suggesting that the volume integration technique should be preferred. All methods are freely available for further testing in the open source environment GetDP/Gmsh. [less ▲]

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See detailA shallow-water model with depth-dependent porosity for urban flood modeling
Bruwier, Martin ULiege; Archambeau, Pierre ULiege; Erpicum, Sébastien ULiege et al

in E-proceedings of the 36th IAHR World Congress (2015, June)

The availability of high-resolution topographic data enables the modeling of urban floods with a high level of accuracy. However, such a modelling has a poor computational efficiency. Subgrid models ... [more ▼]

The availability of high-resolution topographic data enables the modeling of urban floods with a high level of accuracy. However, such a modelling has a poor computational efficiency. Subgrid models enable to decrease the computational time by using coarse cells while preserving information from the detailed topographic data to some degree. In particular, shallow-water models with porosity constitute a subgrid model well-adapted for urban flood modeling. In this article, a new set of fully dynamic shallow-water equations with depth-dependent porosities is presented. Then, the implementation of the model is detailed and preliminary results obtained for a theoretical two-dimensional urban area are analyzed. Unlike recent works, the new model solves the fully dynamic shallow-water equations with depth-dependent and anisotropic porosities, a divergent formulation of the bed slope term, a non-staggered grid with quadrilateral cells and an efficient use of look-up tables to store the porosity relations. [less ▲]

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See detailMutation de l'image, mutation de l'intention ? L'impact des représentations numériques en composition architecturale
Cunin, Maxime; Yang, Maria C.; Elsen, Catherine ULiege

in de Boissieu, Aurélie; Deshayes, Catherine; Tufano, Antonella (Eds.) Mutations du Projet - Milieux et Cultures Numériques (2015, June)

Les architectes ont toujours eu recours à de multiples représentations pour générer, faire évoluer puis communiquer leurs concepts architecturaux (tant aux pairs qu’aux usagers, ou encore aux décideurs ... [more ▼]

Les architectes ont toujours eu recours à de multiples représentations pour générer, faire évoluer puis communiquer leurs concepts architecturaux (tant aux pairs qu’aux usagers, ou encore aux décideurs). Cet article envisage comment la représentation externe impacte la perception « naïve » d’une intention architecturale, les « non experts » assumant des rôles de plus fondamentaux au sein de certains mécanismes décisionnels. Comment l’image, en pleine mutation depuis l’ère du numérique, façonne-t-elle la perception des facteurs clés (ou « attributs ») d’une intention architecturale ? L’article résume les principaux résultats d’une enquête menée en ligne via l’interface « Amazon Mechanical Turk » et générant 790 échelles d’évaluation de 6 avant-projets architecturaux. Les résultats abordent l’analyse des données en regard des différentes attributs; en regard des trois types de représentation choisies et en regard enfin des inconsistances dont font preuve les architectes eux-mêmes, étant donné l’évaluation de leurs propres projets et représentations. Ils révèlent que les attributs ne sont pas équitablement propices à un transfert d’intention exclusivement graphique et que les formes plus abstraites de représentations constituent, dans certains contextes, le moyen le plus efficace pour le transfert fidèle d’une intention architecturale. [less ▲]

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See detailModular modelling of combined AC and DC systems in dynamic simulations
Aristidou, Petros ULiege; Papangelis, Lampros ULiege; Guillaud, Xavier et al

in Proc. of IEEE PES 2015 PowerTech conference (2015, June)

A formulation is proposed in which an AC-DC system is modeled as a combination of AC grids, DC grids, injectors, AC two-ports and AC/DC converters, respectively. This modular modelling facilitates the ... [more ▼]

A formulation is proposed in which an AC-DC system is modeled as a combination of AC grids, DC grids, injectors, AC two-ports and AC/DC converters, respectively. This modular modelling facilitates the dynamic simulation of future complex AC/DC systems. Furthermore, it can be exploited by the solver, which performs less operations on components with lower dynamic activity, and offers parallel processing of the time simulation. This approach is illustrated on a test system in which a multi-terminal DC grid connects two asynchronous AC systems, allows frequency support between them, and acts as emergency control against AC voltage instability. [less ▲]

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See detailL'enseignement du latin à Constantinople : une mise au point
Rochette, Bruno ULiege

in Haverling, Gerd V.M. (Ed.) Latin Linguistics in the Early 21st Century. Acts of the 16th International Colloquium on Latin Linguistics, Uppsala, June 6th-11th, 2011 (2015, June)

Nous savons que Constantinople a possédé une chaire stable de latin vers 360. Plusieurs grammairiens latins qui ont travaillé à Constantinople ou dans d’autres villes du monde grec ont mis au point des ... [more ▼]

Nous savons que Constantinople a possédé une chaire stable de latin vers 360. Plusieurs grammairiens latins qui ont travaillé à Constantinople ou dans d’autres villes du monde grec ont mis au point des artes destinées à un public hellénophone. Les analogies entre le grec et le latin dans la grammaire et le lexique n’ont pas échappé à l’attention à ces grammairiens. Aboutissement d’une tradition qui remonte à Claudius Didymus, Macrobe donne une σύγκρισις du système verbal grec et latin dans son traité De uerborum Graeci et Latini differentiis uel societatibus. Il offre un exemple unique pour l’antiquité de linguistique comparative, mais son but n’est pas pédagogique. Il décrit, mais n’explique pas les ressemblances et les différences entre le système verbal grec et latin. C’est toutefois la même méthode qui est mise en œuvre dans l’enseignement du latin comme L², à savoir l’approche comparative. Le latin s’enseigne aux hellénophone par analogie ou en contraste avec le grec. [less ▲]

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