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See detailMaking high-accuracy null depth measurements for the LBTI exozodi survey
Mennesson, Bertrand; Defrere, Denis ULg; Nowak, Matthias et al

in Malbet, F.; Creech-Eakman, M.; Tuthill, P. (Eds.) Optical and Infrared Interferometry and Imaging V (2016, August 04)

The characterization of exozodiacal light emission is both important for the understanding of planetary systems evolution and for the preparation of future space missions aiming to characterize low mass ... [more ▼]

The characterization of exozodiacal light emission is both important for the understanding of planetary systems evolution and for the preparation of future space missions aiming to characterize low mass planets in the habitable zone of nearby main sequence stars. The Large Binocular Telescope Interferometer (LBTI) exozodi survey aims at providing a ten-fold improvement over current state of the art, measuring dust emission levels down to a typical accuracy of 12 zodis per star, for a representative ensemble of 30+ high priority targets. Such measurements promise to yield a final accuracy of about 2 zodis on the median exozodi level of the targets sample. Reaching a 1 σ measurement uncertainty of 12 zodis per star corresponds to measuring interferometric cancellation ("null") levels, i.e visibilities at the few 100 ppm uncertainty level. We discuss here the challenges posed by making such high accuracy mid-infrared visibility measurements from the ground and present the methodology we developed for achieving current best levels of 500 ppm or so. We also discuss current limitations and plans for enhanced exozodi observations over the next few years at LBTI. [less ▲]

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See detailThe path to interferometry in space
Rinehart, S. A.; Savini, G.; Holland, W. et al

in Malbet, F.; Creech-Eakman, M.; Tuthill, P. (Eds.) Optical and Infrared Interferometry and Imaging V (2016, August 04)

For over two decades, astronomers have considered the possibilities for interferometry in space. The first of these missions was the Space Interferometry Mission (SIM), but that was followed by missions ... [more ▼]

For over two decades, astronomers have considered the possibilities for interferometry in space. The first of these missions was the Space Interferometry Mission (SIM), but that was followed by missions for studying exoplanets (e.g Terrestrial Planet Finder, Darwin), and then far-infrared interferometers (e.g. the Space Infrared Interferometric Telescope, the Far-Infrared Interferometer). Unfortunately, following the cancellation of SIM, the future for space-based interferometry has been in doubt, and the interferometric community needs to reevaluate the path forward. While interferometers have strong potential for scientific discovery, there are technological developments still needed, and continued maturation of techniques is important for advocacy to the broader astronomical community. We review the status of several concepts for space-based interferometry, and look for possible synergies between missions oriented towards different science goals. [less ▲]

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See detailOverview of LBTI: a multipurpose facility for high spatial resolution observations
Hinz, P. M.; Defrere, Denis ULg; Skemer, A. et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2016, August 01)

The Large Binocular Telescope Interferometer (LBTI) is a high spatial resolution instrument developed for coherent imaging and nulling interferometry using the 14.4 m baseline of the 2×8.4 m LBT. The ... [more ▼]

The Large Binocular Telescope Interferometer (LBTI) is a high spatial resolution instrument developed for coherent imaging and nulling interferometry using the 14.4 m baseline of the 2×8.4 m LBT. The unique telescope design, comprising of the dual apertures on a common elevation-azimuth mount, enables a broad use of observing modes. The full system is comprised of dual adaptive optics systems, a near-infrared phasing camera, a 1-5 μm camera (called LMIRCam), and an 8-13 μm camera (called NOMIC). The key program for LBTI is the Hunt for Observable Signatures of Terrestrial planetary Systems (HOSTS), a survey using nulling interferometry to constrain the typical brightness from exozodiacal dust around nearby stars. Additional observations focus on the detection and characterization of giant planets in the thermal infrared, high spatial resolution imaging of complex scenes such as Jupiter's moon, Io, planets forming in transition disks, and the structure of active Galactic Nuclei (AGN). Several instrumental upgrades are currently underway to improve and expand the capabilities of LBTI. These include: Improving the performance and limiting magnitude of the parallel adaptive optics systems; quadrupling the field of view of LMIRcam (increasing to 20"x20"); adding an integral field spectrometry mode; and implementing a new algorithm for path length correction that accounts for dispersion due to atmospheric water vapor. We present the current architecture and performance of LBTI, as well as an overview of the upgrades. [less ▲]

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See detailThe Athena X-ray Integral Field Unit (X-IFU)
Barret, Didier; Trong, Thien Lam; den Herder, Jan-Willem et al

in Proc. SPIE. 9905, Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray, 99052F. (August 17, 2016) (2016, August 01)

The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with 5 ... [more ▼]

The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with 5 arc second pixels over a field of view of 5 arc minute equivalent diameter and a spectral resolution of 2.5 eV up to 7 keV. In this paper, we first review the core scientific objectives of Athena, driving the main performance parameters of the X-IFU, namely the spectral resolution, the field of view, the effective area, the count rate capabilities, the instrumental background. We also illustrate the breakthrough potential of the X-IFU for some observatory science goals. Then we briefly describe the X-IFU design as defined at the time of the mission consolidation review concluded in May 2016, and report on its predicted performance. Finally, we discuss some options to improve the instrument performance while not increasing its complexity and resource demands (e.g. count rate capability, spectral resolution). The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with further ESA member state contributions from Belgium, Finland, Germany, Poland, Spain, Switzerland and two international partners from the United States and Japan. [less ▲]

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See detailEnabling the direct detection of earth-sized exoplanets with the LBTI HOSTS project: a progress report
Danchi, W.; Bailey, V.; Bryden, G. et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2016, August 01)

NASA has funded a project called the Hunt for Observable Signatures of Terrestrial Systems (HOSTS) to survey nearby solar type stars to determine the amount of warm zodiacal dust in their habitable zones ... [more ▼]

NASA has funded a project called the Hunt for Observable Signatures of Terrestrial Systems (HOSTS) to survey nearby solar type stars to determine the amount of warm zodiacal dust in their habitable zones. The goal is not only to determine the luminosity distribution function but also to know which individual stars have the least amount of zodiacal dust. It is important to have this information for future missions that directly image exoplanets as this dust is the main source of astrophysical noise for them. The HOSTS project utilizes the Large Binocular Telescope Interferometer (LBTI), which consists of two 8.4-m apertures separated by a 14.4-m baseline on Mt. Graham, Arizona. The LBTI operates in a nulling mode in the mid-infrared spectral window (8-13 μm), in which light from the two telescopes is coherently combined with a 180 degree phase shift between them, producing a dark fringe at the location of the target star. In doing so the starlight is greatly reduced, increasing the contrast, analogous to a coronagraph operating at shorter wavelengths. The LBTI is a unique instrument, having only three warm reflections before the starlight reaches cold mirrors, giving it the best photometric sensitivity of any interferometer operating in the mid-infrared. It also has a superb Adaptive Optics (AO) system giving it Strehl ratios greater than 98% at 10 μm. In 2014 into early 2015 LBTI was undergoing commissioning. The HOSTS project team passed its Operational Readiness Review (ORR) in April 2015. The team recently published papers on the target sample, modeling of the nulled disk images, and initial results such as the detection of warm dust around η Corvi. Recently a paper was published on the data pipeline and on-sky performance. An additional paper is in preparation on β Leo. We will discuss the scientific and programmatic context for the LBTI project, and we will report recent progress, new results, and plans for the science verification phase that started in February 2016, and for the survey. [less ▲]

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See detailEnhancing Cover Song Identification with Hierarchical Rank Aggregation
Osmalsky, Julien ULg; Van Droogenbroeck, Marc ULg; Embrechts, Jean-Jacques ULg

in Proceedings of the 17th International for Music Information Retrieval Conference (2016, August)

Abstract Cover song identification involves calculating pairwise similarities between a query audio track and a database of reference tracks. While most authors make exclusively use of chroma features ... [more ▼]

Abstract Cover song identification involves calculating pairwise similarities between a query audio track and a database of reference tracks. While most authors make exclusively use of chroma features, recent work tends to demonstrate that combining similarity estimators based on multiple audio features increases the performance. We improve this approach by using a hierarchical rank aggregation method for combining estimators based on different features. More precisely, we first aggregate estimators based on global features such as the tempo, the duration, the loudness, the beats, and the average chroma vectors. Then, we aggregate the resulting composite estimator with four popular state-of-the-art methods based on chromas as well as timbre sequences. We further introduce a refinement step for the rank aggregation called “local Kemenization” and quantify its benefit for cover song identification. The performance of our method is evaluated on the Second Hand Song dataset. Our experiments show an significant improvement of the performance, up to an increase of more than 200 % of the number of queries identified in the Top-1, compared to previous results. [less ▲]

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See detailLa légation des Pays-Bas en cour de Rome au temps de l’agent Laurent du Blioul (1573-1598): Une légation au cœur des réseaux de la monarchie de Philippe II
Regibeau, Julien ULg

in Actes du neuvième congrès de l'Association des Cercles francophones d'Histoire et d'Archéologie de Belgique (2016, August)

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See detailInference in a stochastic SEIR model using Sequential Monte Carlo methods
Bonou, Wilfried ULg; LAMBERT, Philippe

in The 37th Annual Conference of the International Society for Clinical Biostatistics (ISCB): Book of Abstracts. Birmingham, UK, 21-25 August 2016 (2016, August)

Many biological, physical, chemical, economic, and social phenomena are dynamic and are modeled using (systems of) Ordinary Differential Equations (ODEs). But a more realistic way to describe these ... [more ▼]

Many biological, physical, chemical, economic, and social phenomena are dynamic and are modeled using (systems of) Ordinary Differential Equations (ODEs). But a more realistic way to describe these dynamics relies on Discrete Time Markov Chains (DTMC). There is a growing interest in the development of Bayesian statistical methods to infer on the parameters in such dynamic models, particularly those defining epidemic spread, by combining prior information with experimental or observational data. Our proposal aims to explore the merits of the Bayesian Optimal Filtering technique in the estimation of the parameters of a stochastic SEIR (S = Susceptible, E = Exposed, I = Infectious, R = Removed) epidemic model. State Space Models (SSMs) are used to describe the epidemic dynamic. The unknown static parameters are estimated using a combination of Sequential Monte Carlo techniques with a Markov Chain Monte Carlo algorithm, . . . [less ▲]

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See detailOptimal design of flexible mechanisms using a generalized equivalent static load method
Tromme, Emmanuel; Sonneville, Valentin; Guest, James K. et al

in Proceedings of the 24th International Congress of Theoretical and Applied Mechanics (2016, August)

The equivalent static load (ESL) method is a powerful approach to solve dynamic response structural optimization problems. The method transforms the dynamic response optimization into a static response ... [more ▼]

The equivalent static load (ESL) method is a powerful approach to solve dynamic response structural optimization problems. The method transforms the dynamic response optimization into a static response optimization under multiple load cases. The ESLs are defined based on the transient analysis response whereupon all the standard techniques of static response optimization can be used. In the last decade, the ESL method has been applied to perform structural optimization of flexible components of mechanical systems modeled as multibody systems. This method considers the optimization of isolated component during the static response optimization. The present research proposes a generalized ESL method accounting for the entire system during the static response optimization, which enables to formulate the constraints with respect to the mechanism and not restricted to the individual components. The proposed method relies on a Lie group formalism which has appealing properties to derive efficiently the ESL. Examples validate the method. [less ▲]

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See detailFeasibility study of burning neat jatropha oil into a vaporizing burner for household applications.
Sartor, Kevin ULg; Makaire, Danielle; Fontaine, Jean-Marie et al

in Proceedings (2016, August)

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See detailObservation of the surface circulation of the Mediterranean Sea from space
Karimova, Svetlana ULg

in Ouwehand, L. (Ed.) Proc. ESA Living Planet Symposium 2016 (2016, August)

In the present work mesoscale eddies of the Western Mediterranean are being investigated by means of thermal imagery and altimetry data. Comparison of 1489 anticyclonic and 782 cyclonic eddy ... [more ▼]

In the present work mesoscale eddies of the Western Mediterranean are being investigated by means of thermal imagery and altimetry data. Comparison of 1489 anticyclonic and 782 cyclonic eddy manifestations found in sea surface temperature (SST) imagery on an analysis of a 3-year-long dataset (covering the period from 2011 to 2013) with corresponding sea level anomaly (SLA) fields showed that only anticyclonic eddies exceeding ca. 70 km in diameter can be more or less sustainably manifested in the fields of SLA and its derivatives (such as relative vorticity). Detection of cyclonic eddies on base of SLA data, presumably due to the small spatial and temporal scales of such eddies and their non-geostrophic nature, is problematic. [less ▲]

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See detailModelling of multibody systems in the local frame
Bruls, Olivier ULg; Sonneville, Valentin

in Proceedings of the 24th International Congress of Theoretical and Applied Mechanics (ICTAM) (2016, August)

A local frame finite element approach is proposed to describe the kinematics of a flexible multibody system, derive the equations of motion and solve them numerically. It is argued that this approach ... [more ▼]

A local frame finite element approach is proposed to describe the kinematics of a flexible multibody system, derive the equations of motion and solve them numerically. It is argued that this approach leads to reduced geometric nonlinearities and improved computational efficiency. [less ▲]

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See detailOn the compatibility equations in geometrically exact beam finite element
Sonneville; Bruls, Olivier ULg; Bauchau, Olivier A.

in Proceedings of the 12th International Conference on Multibody Systems, Nonlinear Dynamics and Control (MSNDC) within the ASME/IDETC/CIE Conference (2016, August)

This paper discusses the compatibility equations which relate the velocity field and the strain field in geometrically exact beam theory. The analysis is carried out in the context of intrinsic equations ... [more ▼]

This paper discusses the compatibility equations which relate the velocity field and the strain field in geometrically exact beam theory. The analysis is carried out in the context of intrinsic equations, namely the dynamic equilibrium equations are formulated in terms of velocity and strain only. In addition to the well established objectivity and path-independence requirements of the spatial discretization, these compatibility equations show that a consistent spatial interpolation of the velocity field should depend on the curvature of the beam, including initial curvature and curvature from the deformation, and it is shown that this consistency is connected to the ability of the element to represent rigid body motion velocity. A two node interpolation scheme is studied and it appears that, as the element gets smaller under mesh refinement, the effect of this dependency reduces, leading eventually to the classical linear shape functions. [less ▲]

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See detailSmart co-phasing system for segmented mirror telescopes
Simar, Juan Felipe ULg; Stockman, Yvan ULg; Surdej, Jean ULg

in SPIE 9906, Ground-based and Airborne Telescopes VI (2016, July 27)

Space observations of fainter and more distant astronomical objects constantly require telescope primary mirrors with a larger size. The diameter of monolithic primary mirrors is limited to 10 m because ... [more ▼]

Space observations of fainter and more distant astronomical objects constantly require telescope primary mirrors with a larger size. The diameter of monolithic primary mirrors is limited to 10 m because of manufacturing and logistics limitations. For space telescopes, monolithic primary mirrors are limited to less than 5 m due to fairing capacity. Segmented primary mirrors thus constitute an alternative solution to deal with the steadily increase of the primary mirror size. The optical path difference between the individual segments must be close to zero (few nm) in order to be diffraction limited over the full telescope aperture. In this paper a new system that may co-phase 7 segments at once with the light of a star and without artificial one is proposed. First the measuring methods and feedback system is explained, then the breadboard setup is presented and the results are analyzed and discussed, finally a comparison with Keck telescope is performed. This system can be adapted in order to be used in the co-phasing system of future segmented mirrors, its dynamic range starts from several hundred of microns till some tenths of nanometers [less ▲]

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See detailEnd-to-end simulations of the E-ELT/METIS coronagraphs
Carlomagno, Brunella ULg; Absil, Olivier ULg; Kenworthy, Matthew et al

in Marchetti, E.; Close, L.; Véran, J.-P. (Eds.) Adaptive Optics Systems V (2016, July 27)

The direct detection of low-mass planets in the habitable zone of nearby stars is an important science case for future E-ELT instruments such as the mid-infrared imager and spectrograph METIS, which ... [more ▼]

The direct detection of low-mass planets in the habitable zone of nearby stars is an important science case for future E-ELT instruments such as the mid-infrared imager and spectrograph METIS, which features vortex phase masks and apodizing phase plates (APP) in its baseline design. In this work, we present end-to-end performance simulations, using Fourier propagation, of several METIS coronagraphic modes, including focal-plane vortex phase masks and pupil-plane apodizing phase plates, for the centrally obscured, segmented E-ELT pupil. The atmosphere and the AO contributions are taken into account. Hybrid coronagraphs combining the advantages of vortex phase masks and APPs are considered to improve the METIS coronagraphic performance. [less ▲]

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See detailThe QACITS pointing sensor: from theory to on-sky operation on Keck/NIRC2
Huby, Elsa ULg; Absil, Olivier ULg; Mawet, Dimitri et al

in Marchetti, E.; Close, L.; Véran, J.-P. (Eds.) Adaptive Optics Systems V (2016, July 26)

Small inner working angle coronagraphs are essential to benefit from the full potential of large and future extremely large ground-based telescopes, especially in the context of the detection and ... [more ▼]

Small inner working angle coronagraphs are essential to benefit from the full potential of large and future extremely large ground-based telescopes, especially in the context of the detection and characterization of exoplanets. Among existing solutions, the vortex coronagraph stands as one of the most effective and promising solutions. However, for focal-plane coronagraph, a small inner working angle comes necessarily at the cost of a high sensitivity to pointing errors. This is the reason why a pointing control system is imperative to stabilize the star on the vortex center against pointing drifts due to mechanical flexures, that generally occur during observation due for instance to temperature and/or gravity variations. We have therefore developed a technique called QACITS[SUP]1[/SUP] (Quadrant Analysis of Coronagraphic Images for Tip-tilt Sensing), which is based on the analysis of the coronagraphic image shape to infer the amount of pointing error. It has been shown that the flux gradient in the image is directly related to the amount of tip-tilt affecting the beam. The main advantage of this technique is that it does not require any additional setup and can thus be easily implemented on all current facilities equipped with a vortex phase mask. In this paper, we focus on the implementation of the QACITS sensor at Keck/NIRC2, where an L-band AGPM has been recently commissioned (June and October 2015), successfully validating the QACITS estimator in the case of a centrally obstructed pupil. The algorithm has been designed to be easily handled by any user observing in vortex mode, which is available for science in shared risk mode since 2016B. [less ▲]

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See detailCommissioning and first light results of an L'-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument
Femenía Castellá, Bruno; Serabyn, Eugene; Mawet, Dimitri et al

in Marchetti, E.; Close, L.; Véran, J.-P. (Eds.) Adaptive Optics Systems V (2016, July 26)

On March 2015 an L'-band vortex coronagraph based on an Annular Groove Phase Mask made up of a diamond sub-wavelength grating was installed on NIRC2 as a demonstration project. This vortex coronagraph ... [more ▼]

On March 2015 an L'-band vortex coronagraph based on an Annular Groove Phase Mask made up of a diamond sub-wavelength grating was installed on NIRC2 as a demonstration project. This vortex coronagraph operates in the L' band not only in order to take advantage from the favorable star/planet contrast ratio when observing beyond the K band, but also to exploit the fact that the Keck II Adaptive Optics (AO) system delivers nearly extreme adaptive optics image quality (Strehl ratios values near 90%) at 3.7μm. We describe the hardware installation of the vortex phase mask during a routine NIRC2 service mission. The success of the project depends on extensive software development which has allowed the achievement of exquisite real-time pointing control as well as further contrast improvements by using speckle nulling to mitigate the effect of static speckles. First light of the new coronagraphic mode was on June 2015 with already very good initial results. Subsequent commissioning nights were interlaced with science nights by members of the VORTEX team with their respective scientific programs. The new capability and excellent results so far have motivated the VORTEX team and the Keck Science Steering Committee (KSSC) to offer the new mode in shared risk mode for 2016B. [less ▲]

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See detailArchitectural and Environmental Housing Typology Analysis in Huamachuco, Peru
Meliani, Houmam ULg; Teller, Jacques ULg; Attia, Shady ULg

in La Roche, Pablo; Schiler, Marc (Eds.) Passive and Low Energy Architecture Conference (2016, July 12)

This work focuses on the city of Huamachuco, a town 3200 meters above sea level in Northern Peru. The main aim of this study is to share and disseminate technological knowledge on architecture, building ... [more ▼]

This work focuses on the city of Huamachuco, a town 3200 meters above sea level in Northern Peru. The main aim of this study is to share and disseminate technological knowledge on architecture, building technology and lifestyle of Huamachuco inhabitants. The paper objective is to (1) highlight the concept of architectural quality in Huamachuco, (2) compare the living environment of existing traditional dwellings in comparison with newly constructed concrete dwellings, and to (3) identify the reasons for neglecting ecological construction technologies and materials in the new built environment. The research methodology went through different phases that range from qualitative data collection and quantitative measuring, to data analysis and findings reporting. Firstly, a typological study was conducted visiting 110 houses. The typological study enabled us to describe and understand the housing typologies and classify those under four major typologies according to their construction techniques: 1) adobe, 2) rammed earth, 3) concrete and 4) mixed technique. Secondly, detailed field studies were conducted for representative houses representing the four categories. Finally, 10 houses have been thoroughly audited for using measuring equipment to collect data related to temperature, relative humidity, carbon dioxide concentration, lighting intensity, and envelope thermography. [less ▲]

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See detailExperimental results for hydrocarbon refrigerant vaporization in brazed plate heat exchangers at high pressure
Desideri, Adriano ULg; Rhyl Kaern, Martin; Ommen Schmidt, Torben et al

in Proceedings of the 16th International Refrigeration and Air Conditioning Conference at Purdue (2016, July 11)

In recent years the interest in small capacity organic Rankine cycle (ORC) power systems for harvesting low quality waste thermal energy from industrial processes has been steadily growing. Micro ORC ... [more ▼]

In recent years the interest in small capacity organic Rankine cycle (ORC) power systems for harvesting low quality waste thermal energy from industrial processes has been steadily growing. Micro ORC systems are normally equipped with brazed plate heat exchangers which allows for efficient heat transfer with a compact design. An accurate prediction of the heat transfer process characterizing these devices is required from the design phase to the development of model- based control strategies. The current literature is lacking experimental data and validated correlations for vaporization of organic fluids at typical working conditions of ORC systems for low temperature waste heat recovery (WHR) applications. Based on these premises, a novel test-rig has been recently designed and built at the Technical University of Denmark to simulate the evaporating condition occurring in a small capacity ORC power unit. In this contribution the preliminary experimental results obtained from the first experimental campaign carried out on the rig are reported. HFC-134a was selected as working fluid. The experiments were carried out at saturation temperature of 60, 70 and 80 ○C and inlet and outlet qualities ranging between 0.01-0.3 and 0.5-0.95 respectively. The heat flux ranged between 19.4 and 43.1 kWm−2. The results are presented in terms of refrigerant side heat transfer coefficient and pressure drop. The heat transfer coefficient showed significant sensitivity to the saturation temperature and was characterized by a decreasing trend with respect to the mean evaporator quality. The frictional pressure drop showed a linear dependence on the mean quality value and increased as the saturation temperature decreased. The experimental heat transfer coefficients were compared with a well-known correlation for nucleate boiling which is able to predict the results with an accuracy of around 20 %. [less ▲]

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See detailA Novel Methodology for Hybrid Fire Testing
Sauca, Ana ULg; Gernay, Thomas ULg; Robert, Fabienne et al

in Proceedings of the 6th European Conference on Structural Control (2016, July 11)

This paper describes a novel methodology for conducting stable hybrid fire testing (HTF). During hybrid fire testing, only a part of the structure is tested in a furnace while the reminded structure is ... [more ▼]

This paper describes a novel methodology for conducting stable hybrid fire testing (HTF). During hybrid fire testing, only a part of the structure is tested in a furnace while the reminded structure is calculated separately, here by means of a predetermined matrix. Equilibrium and compatibility at the interface between the tested “physical substructure” and the “numerical substructure” is maintained throughout the test using a dedicated algorithm. The procedures developed so far are sensitive to the stiffness ratio between the physical and the numerical substructure and therefore they can be applied only in some cases. In fire field, the stiffness of the heated physical substructure may change dramatically and the resulting change in stiffness ratio can lead to instability during the test. To overcome this drawback, a methodology independent of the stiffness ratio has been developed, inspired from the Finite Element Tearing and Interconnecting (FETI) method, which has been originally developed for substructuring in numerical analyses. The novel methodology has been successfully applied to a hybrid fire test in a purely numerical environment, i.e. the physical substructure was also modelled numerically. It is shown that stability does not depend on the stiffness ratio and that equilibrium and compatibility can be consistently maintained at the interface during the fire. Finally, the ongoing experimental program aimed at employing and experimentally validating this methodology is described. [less ▲]

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See detailL’argumentation de l’image scientifique : une affaire de méréologie
Dondero, Maria Giulia ULg

in Pollet, Marie-Christine; Glorieux, Carole (Eds.) Argumenter dans les écrits scientifiques (2016, July 07)

Ce texte vise à étudier, dans une perspective sémiotique, le discours scientifique de recherche et celui de la vulgarisation et notamment les images présentes dans ces deux genres de discours. Nous ... [more ▼]

Ce texte vise à étudier, dans une perspective sémiotique, le discours scientifique de recherche et celui de la vulgarisation et notamment les images présentes dans ces deux genres de discours. Nous examinons des travaux relevant de l’astrophysique et notamment la manière dont les images argumentent. Le corpus sera abordé à partir de la notion de rhétorique entendue comme un ensemble d’opérations méréologiques. Nous reprendrons à ce propos la théorie de l’iconicité de Jean-François Bordron, illustrée par ses deux derniers livres, L’iconicité et ses images (2011) ainsi qu’Image et vérité. Essais sur la dimension iconique de la connaissance (2013). [less ▲]

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See detailOVMS-plus at the LBT: disturbance compensation simplified
Böhm, Michael; Pott, Jörg-Uwe; Borelli, José et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2016, July 01)

In this paper we will briefly revisit the optical vibration measurement system (OVMS) at the Large Binocular Telescope (LBT) and how these values are used for disturbance compensation and particularly for ... [more ▼]

In this paper we will briefly revisit the optical vibration measurement system (OVMS) at the Large Binocular Telescope (LBT) and how these values are used for disturbance compensation and particularly for the LBT Interferometer (LBTI) and the LBT Interferometric Camera for Near-Infrared and Visible Adaptive Interferometry for Astronomy (LINC-NIRVANA). We present the now centralized software architecture, called OVMS+, on which our approach is based and illustrate several challenges faced during the implementation phase. Finally, we will present measurement results from LBTI proving the effectiveness of the approach and the ability to compensate for a large fraction of the telescope induced vibrations. [less ▲]

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See detailThe filter wheel and filters development for the X-IFU instruments onboard Athena
Bozzo, E.; Barbera, M.; Genolet, L. et al

in den Herder, Jan-Willem, A.; Takahashi, Tadayuki; Bautz, Marshall (Eds.) Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2016, July 01)

Athena is the large mission selected by ESA in 2013 to investigate the science theme "Hot and Energetic Universe" and presently scheduled for launch in 2028. One of the two instruments located at the ... [more ▼]

Athena is the large mission selected by ESA in 2013 to investigate the science theme "Hot and Energetic Universe" and presently scheduled for launch in 2028. One of the two instruments located at the focus of the 12 m-long Athena telescope is the X-ray Integral Field Unit (X-IFU). This is an array of TES microcalorimeters that will be operated at temperatures of 50 mK in order to perform high resolution spectroscopy with an energy resolution down to 2.5 eV at energies < 7 keV. In order to cope with the large dynamical range of X-ray fluxes spanned by the celestial objects Athena will be observing, the X-IFU will be equipped with a filter wheel. This will allow the user to fine tune the instrument set-up based on the nature of the target, thus optimizing the scientific outcomes of the observation. A few positions of the filter wheel will also be used to host a calibration source and to allow the measurement of the instrument intrinsic background. [less ▲]

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See detailValidity and reliability of the French translation of the Patient-Related Tennis Elbow Evaluation Questionnaire
Kaux, Jean-François ULg; DELVAUX, François ULg; SCHAUS, Jean ULg et al

in Crossing borders through sport science (2016, July)

Background: The lateral elbow tendinopathy is a common injury in tennis players and physical workers. The Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaire was created to measure pain and ... [more ▼]

Background: The lateral elbow tendinopathy is a common injury in tennis players and physical workers. The Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaire was created to measure pain and functional disabilities specifically reported in patient with lateral epicondylitis (tennis elbow). Developed in English, this questionnaire has since then been translated into several languages but not in French. Objectives: The aims of the study were to translate and cross-culturally adapt the PRTEE questionnaire into French and to evaluate the reliability and validity of this new version of the questionnaire (PRTEE-F). Methods: The PRTEE was cross-culturally adapted into French according to the international guidelines. To assess the reliability and validity of the PRTEE-F, 115 participants filled in the PRTEE-F twice, and the Disabilities of Arm, Shoulder and Hand questionnaire (DASH) and the Short Form Health Survey (SF-36) once. Internal consistency (with Cronbach’s alpha), test-retest reliability (with intra-class correlation (ICC)), convergent and divergent validity (by calculating the Spearman’s correlation coefficients with the DASH and some sub scales of the SF-36, respectively) were assessed. Results: The PRTEE was translated in French without problem. PRTEE-F showed a good test-retest reliability for the overall score (ICC 0.83) and for each items (ICC 0.71-0.9) and a high internal consistency (Cronbach’s alpha = 0.98). The correlation analyses revealed high correlation coefficients between PRTEE-F and DASH (good convergent validity) and, as expected, a low or moderate correlations with the divergent subscales of the SF-36 (discriminant validity). There was no floor or ceiling effect. Conclusions: The PRTEE questionnaire was successfully cross-culturally adapted into French the PRTEE-F is reliable and valid for evaluating the French-speaking patient with lateral elbow tendinopathy. [less ▲]

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See detail2D and 3D FE models of laser cladding process
Jardin, Ruben; Hoang, Son Tran; Hashemi, Seyedeh Neda ULg et al

in Booklet of the conference with extended abstract and short paper of less than 6 pages (2016, July)

Lien entre le champ thermique 2D et 3D calculé pour un cas de laser cladding d acier au chrome

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See detailTowards a Multipath TCP Aware Load Balancer
Lienardy, Simon ULg; Donnet, Benoît ULg

in Applied Networking Research Workshop (2016, July)

Multipath TCP has been recently introduced in order to allow a better resource consumption and user quality-of-experience. This is achieved by allowing a connection between two hosts through multiple ... [more ▼]

Multipath TCP has been recently introduced in order to allow a better resource consumption and user quality-of-experience. This is achieved by allowing a connection between two hosts through multiple subflows. However, with the rise of middleboxes and inherent Internet ossification, the large-scale deployment of this TCP extension is difficult. In particular, a load balancer at the entry point of a data center may forward subflows to different servers, canceling so the advantages of Multipath TCP. In this paper, we introduce MpLB, a Multipath TCP aware load balancer that fixes this particular issue without any modification to the Multipath TCP protocol itself. We demonstrate advantages of MpLB through a proof-of-concept. [less ▲]

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See detailLoad modulation strategies of residential heat pumps for demand-response programs with different thermal storage options
Georges, Emeline ULg; Lemort, Vincent ULg

in Proceedings of the 4th International High Performance Buildings Conference at Purdue (2016, July)

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See detailInventaire et typologie des listes grecques et latines de produits pharmaceutiques
Ricciardetto, Antonio ULg

in Derda, Tomasz; Lajtar, Adam; Urbanik, Jakub (Eds.) Proceedings of the XXVIIth International Congress of Papyrology. Warsaw, 29 July - 3 August 2013 (2016, July)

Dans la documentation papyrologique relative aux pratiques médicales de l’Égypte gréco-romaine et byzantine, le genre des listes de produits pharmaceutiques n’a encore jamais fait l’objet, ni d’un ... [more ▼]

Dans la documentation papyrologique relative aux pratiques médicales de l’Égypte gréco-romaine et byzantine, le genre des listes de produits pharmaceutiques n’a encore jamais fait l’objet, ni d’un inventaire, ni d’une étude exhaustifs. Dans le cadre de nos recherches doctorales sur la typologie des papyrus documentaires grecs et latins à caractère médical, c’est cette lacune que l’on se propose de combler, d’une part en cataloguant, au moyen de la fiche Mertens-Pack³ du CEDOPAL, la trentaine de listes de produits pharmaceutiques provenant d’Égypte, écrites en grec sur papyrus et ostracon (IIIe s. av. J.-Chr.-VIIe s. apr. J.-Chr.), auxquelles on ajoutera deux listes latines sur tablettes de bois, provenant du camp romain de Vindolanda (c. 100p), et, d’autre part, en analysant les aspects formels, paléographiques, textuels et contextuels de ces documents médicaux qui peuvent correspondre, soit à un inventaire de droguiste, soit à une commande, soit à une ou plusieurs recettes dont l’état fragmentaire du support a fait disparaître les proportions. On comparera les données obtenues avec d’autres pièces papyrologiques, spécialement les nombreuses prescriptions médicales, ainsi que les comptes, les reçus de paiement ou encore les lettres privées relatives à des demandes de médicaments ou à la livraison de substances pharmaceutiques. [less ▲]

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See detailLeibniz et J.S. Bach
Dony, Arthur ULg

in Li, Wenchao (Ed.) "Für unser Glück oder das Glück anderer" : Vorträge des X. Internationalen Leibniz-Kongresses (2016, July)

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See detailApplications of the multiple timescale spectral analysis in wind engineering
Denoël, Vincent ULg

in Zingoni, Alphose (Ed.) Proceedings of the Sixth International Conference on Structural Engineering, Mechanics and Computation (2016, July)

The random response of civil engineering structures to the buffeting action of wind loads is typically composed of several components, usually referred to as the background component, in the low fre ... [more ▼]

The random response of civil engineering structures to the buffeting action of wind loads is typically composed of several components, usually referred to as the background component, in the low fre- quency zone and the resonant component(s) in the neighborhood of modal natural frequencies. It has become customary to study separately and add the contributions of these components to the total response, at least as far as the second order response (variance of structural responses) is concerned. Such a decomposition exists but is less usual for the computation of covariances of modal coordinates or of structural displacements, which are in turn necessary for the determination of internal stresses. The question of such a decomposition also holds for nonlinear systems, or even for the higher statistical moments of a linear structural system, should the response be non Gaussian. With very wide ranges of applicability, the Multiple Timescale Spectral Analysis summarizes under a unified framework recent works aiming at the development of such decompositions. This paper briefly pictures this particular theory based on perturbation methods, and provides illustrations of its applicability to the problems cited above. [less ▲]

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See detailNew spore data from the Lower Devonian Posongchong Formation from Wenshan, Yunnan, China
Cascales-Miñana, Borja ULg; Rial, Gonzalo; Xue, Jinzhuang et al

in 4th International Meeting of Agora Paleobotanica, Brussels 7-10 July 2016 (2016, July)

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See detailTowards an Observatory for Network Transparency Research
Neuhaus, Stephan; Münter, Roman; Edeline, Korian ULg et al

in Applied Networking Research Workshop (2016, July)

The Internet is full of middleboxes that change packets and flows. In fact, there is probably no IP or TCP header that is not affected by at least one middlebox. Obviously, middleboxes impede path ... [more ▼]

The Internet is full of middleboxes that change packets and flows. In fact, there is probably no IP or TCP header that is not affected by at least one middlebox. Obviously, middleboxes impede path transparency, i.e., the idea that an exchange of messages results in more or less the same packets, no matter what path the packets takes. But no one seems to have a truly global view of what middleboxes do to packets on what Internet paths, which would however be an essential knowledge for new transport protocols to be successfully deployed. We address these concerns in the MAMI project by building an observatory of path transparency measurements. The project hosts an extensive set of path transparency measurements - we believe it to be the first dataset to deal specifically with middlebox involvement. In this paper, we describe that Observatory and a number of questions that we want to address with the data in that Observatory. Eventually, the project will provide public access to that Observatory so that researchers and the interested public can ask their own questions about path transparency issues and middlebox involvement. [less ▲]

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See detailA vascular plant precursor from North Gondwana
Cascales-Miñana, Borja ULg; Gerrienne, Philippe ULg

in 4th International Meeting of Agora Paleobotanica, Brussels 7-10 July 2016 (2016, July)

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See detailSensitivity of the breaching process in the case of overtopping induced fluvial dike failure
Rifai, Ismail ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in River Flow 2016 Proceedings (2016, July)

Fluvial dikes are common structures constructed for flow channelization, prevention of river bed lateral migration and for flood protection purposes. Their aging increases their vulnerability to extreme ... [more ▼]

Fluvial dikes are common structures constructed for flow channelization, prevention of river bed lateral migration and for flood protection purposes. Their aging increases their vulnerability to extreme hydro-logical events, and subsequently may cause their failure. Many laboratory studies of overtopping induced dike failure were conducted, dealing mainly on normal configurations (i.e. dam break configuration) without ac-counting for the influence of a parallel flow. The fluvial dike breaching process remains, therefore, insuffi-ciently studied. A simplified model assuming a parameterized evolution of the breach geometry has been de-veloped to evaluate the fluvial breaching process. Results showed a sensitivity of the breaching process to the main channel configuration and to the flow conditions. Also, the evolution mode that was prescribed for the breach cross-section strongly influences the breaching duration and the sediment discharge [less ▲]

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See detailFirst on-sky results with ARGOS at LBT
Orban De Xivry, Gilles ULg; Rabien, Sebastian; Busoni, Lorenzo et al

in First on-sky results with ARGOS at LBT (2016, July)

One year and an half after ARGOS first light, the Large Binocular Telescope (LBT) laser guided ground-layer adaptive optics (GLAO) system has been operated on both sides of the LBT. The system fulfills ... [more ▼]

One year and an half after ARGOS first light, the Large Binocular Telescope (LBT) laser guided ground-layer adaptive optics (GLAO) system has been operated on both sides of the LBT. The system fulfills the GLAO promise and typically delivers an improvement by a factor of 2 in FWHM over the 4'×4' field of view of both Luci instruments, the two near-infrared imagers and multi-object spectrographs. In this paper, we report on the first on-sky results and analyze the performances based on the data collected so far. We also discuss adaptive optics procedures and the joint operations with Luci for science observations. [less ▲]

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See detailLeveraging orientation knowledge to enhance human pose estimation methods
Azrour, Samir ULg; Pierard, Sébastien ULg; Van Droogenbroeck, Marc ULg

in Articulated Motion and Deformable Objects AMDO 2016 (2016, July)

Predicting accurately and in real-time 3D body joint positions from a depth image is the cornerstone for many safety, biomedical, and entertainment applications. Despite the high quality of the depth ... [more ▼]

Predicting accurately and in real-time 3D body joint positions from a depth image is the cornerstone for many safety, biomedical, and entertainment applications. Despite the high quality of the depth images, the accuracy of existing human pose estimation methods from single depth images remains insufficient for some applications. In order to enhance the accuracy, we suggest to leverage a rough orientation estimation to dynamically select a 3D joint position prediction model specialized for this orientation. This orientation estimation can be obtained in real-time either from the image itself, or from any other clue like tracking. We demonstrate the merits of this general principle on a pose estimation method similar to the one used with Kinect cameras. Our results show that the accuracy is improved by up to 45.1 %, with respect to a method using the same model for all orientations. [less ▲]

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See detailImpact of a mountain ultra-marathon on cardiac biomarkers
Le Goff, Caroline ULg; Gergelé, Laurent; Kaux, Jean-François ULg et al

in Crossing borders through sport science (2016, July)

Objectives. While moderate exercise has beneficial effects on the cardiovascular system, consequences of a supra-physiological effort are not clear yet. In particular, the physiological consequences of ... [more ▼]

Objectives. While moderate exercise has beneficial effects on the cardiovascular system, consequences of a supra-physiological effort are not clear yet. In particular, the physiological consequences of ultramarathons need to be further documented. The aim of the study was to assess the changes of various cardiac biomarkers after a mountain ultra-marathon. Material and methods. Blood and urine samples were collected on 28 runners (17 men) participating to the Ultra-Trail du Mont Blanc (105km, total positive elevation: 5600 m) at 3 different times: before the race (Pre), within 1 h after the finish (Post) and 7 days after the finish (D+7). Several biomarkers involved in heart disease (coronary syndrome, heart failure and fibrosis) and in inflammation were assayed on different analyzers such a COBAS® (for CKMB,TnThs, NT-proBNP, H-FABP and CRPs) and KRYPTOR® (for Copeptin). ST2 was measured manually with the Presage kit from CRITICAL DIAGNOSTIC®. Results. Plasma levels of cardiac markers (CKMB, TnThs, NT-proBNP, copeptin, H FABP, ST2) and inflammation (CRPs) increased significantly at Post. Means values increased from Pre to Post as follows: 2.3 to 91.9 UI/L for CKMB (p<0.0001); 7.6 to 31.7 ng/L for TnThs (p<0.0001); 41.7 to 1190.5 ng/L for NT-proBNP, 4.2 to 22.9 pmol/L for copeptin (p=0.001); 3.6 to 107.8 ng/mL for H-FABP (p<0.0001), 29.7 to 126.2 ng/mL for ST2 (p<0.0001); 0.5 to 29.1 mg/L for CRPs (p<0.0001). With the exception of a few (H-FABP, ST2, CRPs) biomarkers in some subjects, all values were back to Pre values at D+7. Discussion-conclusion. Prolonged strenuous running exercise caused an elevation in cardiac biomarkers. Elevation in CK-MB levels lacks specificity for cardiac damage as runners have increased CKMB from skeletal muscles as well. Previous studies suggested that exercise induced TnThs elevation is a benign reversible physiologic phenomenon but this parameter, as well as H-FABP, could be a sign of ischemia. Different phenomena occurred such as stretch of myocytes causing an increase in pressure or volume and neurohormonal activation which can explain the Copeptine and NT-proBNP increase, while ST2 is a biomarker of cardiac remodeling and fibrosis. CRP is an acute phase compound that tends to increase following a strenuous and prolonged bout of exercise and/or muscular injury. As the values tended to return within the normal reference range values within 7 days after the race, our study suggests that there is no permanent structural damage at the myocardium level. [less ▲]

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See detailTechno-economic evaluation of self-consumption with PV/battery systems under different regulation schemes
Quoilin, Sylvain ULg; Zucker, Andreas

in Proceedings of the 29th international conference on Efficiency, Cost, Optimisation, Simulation and Environmental Impact of Energy Systems (2016, July)

The recent disclosure of new and innovative home battery systems has been seen by many as a catalyser for a solar energy revolution, and has created high expectations in the sector. Many observers have ... [more ▼]

The recent disclosure of new and innovative home battery systems has been seen by many as a catalyser for a solar energy revolution, and has created high expectations in the sector. Many observers have predicted an uptake of combined PV/Battery units, which, could ultimately disconnect from the grid and lead to autonomous homes or mini-grids. However, most of the comments originating from social media, blogs or press articles lack proper cost evaluation and realistic simulations. This work aims at bridging this gap by simulating self-consumption in different EU countries, for different household profiles with or without battery. Results indicate that (1) Although decreasing at a fast pace, the cost of domestic Li-Ion storage is most likely still too high for a large-scale market uptake in Europe; (2) PV incentives based on net metering are not favourable to home batteries; (3) Home battery profitability and future uptake mainly depend on the indirect self-consumption subsidies provided by the structure of the retail prices; (4) These systems do not allow residential consumers to go off-grid. They only allow for a maximum self-sufficiency ratio close to 70%. [less ▲]

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See detailAn Empirical Investigation of Data Governance: The Role of Accountabilities
Kamioka, Taro; Luo, Xubin; Tapanainen, Tommi ULg

in Proceedings of the Pacific-Asian Conference on Information Systems (PACIS) (2016, June 30)

Data governance has recently received attention as a way to improve company-wide data quality management. As with other governance concepts, accountabilities is central to data governance - roles and ... [more ▼]

Data governance has recently received attention as a way to improve company-wide data quality management. As with other governance concepts, accountabilities is central to data governance - roles and responsibilities must be introduced that facilitate the processing of data according to company needs. Marketing is one business area where data-driven decision-making has shown promise, and which is likely to benefit from company-wide data governance. However, empirical investigations of data governance are still limited. This research analysed survey data in Japan that investigated the hypothesized relationships of accountabilities in data governance to perceived performance in marketing activities via the intermediate variable of data utilization. The research found positive links between these variables, showing one avenue by which data governance is effective. However, it should be noted that in the case of larger companies, this link was confirmed only between accountabilities and data utilization. In practical terms, the result can be used to promote data governance in companies. Future research potential is suggested at the end of the paper. [less ▲]

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See detailNappe Vibration Mitigation Techniques for Free-overfall Structrures
Lodomez, Maurine ULg; Crookston, Brian M.; Tullis, Blake P. et al

in Full Proceedings: Hydraulic Structures and Water System Management (2016, June 27)

Nappe vibration is a phenomenon that has been witnessed in the field for a variety of different free overflow hydraulic structures operating at low heads, such as fountains, crest gates, and weirs. This ... [more ▼]

Nappe vibration is a phenomenon that has been witnessed in the field for a variety of different free overflow hydraulic structures operating at low heads, such as fountains, crest gates, and weirs. This phenomenon is visually characterized by oscillations in the thin nappe cascading downstream of the control structure. These oscillations can produce a significant level of noise and acoustic pressure waves, which can increase the environmental and societal impacts of the hydraulic structure. As a result, a detailed investigation has been undertaken to identify practical and effective mitigation solutions for free-overfall structures where nappe vibration may be of concern. Research is being performed with a prototype-scale linear weir (weir length of 3.5 m and fall height of 3 m) located at the Engineering Hydraulics laboratory of the University of Liège, to assess the effectiveness of various crest modifications and any corresponding impacts to hydraulic efficiency (i.e., flow rate). The test matrix includes the optimization (position and spacing of elements) of three mitigation solutions which are projecting bolts, deflectors and step. In addition, a high-speed camera and audio equipment have been used to evaluate effectiveness of the configurations in reducing nappe vibration. Finally, this practical study has identified countermeasures suitable for retrofits and new construction, easy to construct, durable, hydraulically efficient, and with minimal potential for debris collection. [less ▲]

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See detailThree years of harvest with the vector vortex coronagraph in the thermal infrared
Absil, Olivier ULg; Mawet, D.; Karlsson, M. et al

in Evans, C.; Simard, L.; Takami, H. (Eds.) Ground-based and Airborne Instrumentation for Astronomy VI (2016, June 26)

For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to ... [more ▼]

For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to be used in the thermal infrared (ranging from 3 to 13 μm). Our AGPMs were first installed on VLT/NACO and VLT/VISIR in 2012, followed by LBT/LMIRCam in 2013 and Keck/NIRC2 in 2015. In this paper, we review the development, commissioning, on-sky performance, and early scientific results of these new coronagraphic modes and report on the lessons learned. We conclude with perspectives for future developments and applications. [less ▲]

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See detailReceding-Horizon Control of Distributed Generation to Correct Voltage or Thermal Violations and Track Desired Schedules
Soleimani Bidgoli, Hamid ULg; Glavic, Mevludin ULg; Van Cutsem, Thierry ULg

in Proceedings of the 19th PSCC (2016, June 23)

This paper presents a real-time, centralized control system acting on the active and reactive powers of distributed generators when the network experiences voltage and/or thermal limits violation. The ... [more ▼]

This paper presents a real-time, centralized control system acting on the active and reactive powers of distributed generators when the network experiences voltage and/or thermal limits violation. The control resorts on multi-step receding-horizon optimization. The objective is to minimize the deviations of Dispersed Generation Units (DGU) active and reactive powers from reference values. The reactive power corrections have priority over the active ones. Furthermore, the formulation is such that DGU powers are restored to their desired schedule as soon as operating conditions allow doing so. Three modes of operation of the proposed controller are presented, involving dispatchable units as well as DGUs operated to track maximum power output. The effectiveness of the proposed control is illustrated through detailed simulations of a 75-bus, 11-kV system hosting 22 DGUs. [less ▲]

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See detailOrganic Rankine cycle modelling and the ORCmKit library: analysis of R1234ze(Z) as drop-in replacement of R245fa for low-grade waste heat recovery
Ziviani, Davide; Dickes, Rémi ULg; Quoilin, Sylvain ULg et al

in Proceedings of ECOS 2016 (2016, June 20)

Due to the wide interest in organic Rankine cycles (ORCs) as a sustainable technology and the importance of numerical analyses and optimization procedures while considering such systems, we created a ... [more ▼]

Due to the wide interest in organic Rankine cycles (ORCs) as a sustainable technology and the importance of numerical analyses and optimization procedures while considering such systems, we created a dedicated open-source library named “ORC modelling Kit” (ORCmKit). The comprehensive library includes single com-ponents and overall models for subcritical, transcritical and supercritical ORCs. Three main programming environments are currently supported: Matlab, Python and EES (Engineering Equation Solver). A detailed steady-state cycle model of a small-scale regenerative ORC with a single-screw expander is used to evalu-ate the performance influence of R1234ze(Z) as a drop-in replacement of R245fa currently used in the instal-lation. The ORC system is used to recover low-grade waste heat with a temperature range between 90°C and 120°C. A thermal oil heater is used to simulate the heat source. A parametric study is carried out to in-vestigate the performance of the system throughout the range of interest in order to optimize the ORC with R1234ze(Z). [less ▲]

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See detailORCmKit: an open-source library for organic Rankine cycle modelling and analysis
Dickes, Rémi ULg; Ziviani, Davide; van den Broek, Martjin et al

in Proceedings of ECOS 2016 (2016, June 20)

As for many other technologies, modelling and simulation of organic Rankine cycles (ORCs) are crucial for design, optimization and control purposes. However, model development is often time consuming and ... [more ▼]

As for many other technologies, modelling and simulation of organic Rankine cycles (ORCs) are crucial for design, optimization and control purposes. However, model development is often time consuming and the scientific community lacks of open-access tools to study ORC systems. For these reasons, researchers from the universities of Liège and Ghent in Belgium gathered their knowledge and created “ORC modelling Kit” (ORCmKit), an open-source library dedicated to the steady-state simulation and analysis of organic Rankine cycles. Both component-level and cycle-level models are provided and different ORC architectures can be simulated. For each of the main component of ORC systems, different models are available with increasing complexity which allows a wide range of modelling possibilities. In order to remain general and accessible to as many people as possible, three widely used programming languages are covered within ORCmKit, i.e. Matlab, Python and EES (Engineering Equation Solver). Besides source codes, ORCmKit also includes calibration tools for empirical and semi-empirical models as well as a complete documentation for ease of use. [less ▲]

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See detailSteady-state and dynamic modelling of a 1 MWel commercial waste heat recovery ORC power plant
Andritsos, George; Desideri, Adriano ULg; Gantiez, Clement et al

in Steady-state and dynamic modelling of a 1 MWel commercial waste heat recovery ORC power plant (2016, June 19)

ORC power systems have been proven to be a mature technology for low quality waste heat recovery applications. ORC units stand out for their simple structure, reliability and cost- effectiveness. The non ... [more ▼]

ORC power systems have been proven to be a mature technology for low quality waste heat recovery applications. ORC units stand out for their simple structure, reliability and cost- effectiveness. The non-constant nature of the energy source requires the ORC power unit to be flexible. Dynamic modelling can be adopted to evaluate and optimize the response time of a system in case of transient conditions, to develop and test control strategies, to support the tuning of the controller and to support maintenance. In this work the dynamic model of a 1 MWel commercial ORC unit is presented. The dynamic model is developed based on the ThermoCycle Modelica library. The different component model are validated in steady-state against 21 measurements points. The dynamic model of the whole power unit is then developed connecting the validated component models. Different modelling approaches of various complexity are implemented to model the heat exchangers of the power system. The performance of the developed heat exchanger (HX) models are tested by running different transient simulations. The results allow identifying benefits and limitations of the tested HX modelling approaches. [less ▲]

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See detailEvaluation of Adaptive Facades: The Case Study of AGC Headquarter in Belgium
Attia, Shady ULg; Bashandy, Hamza

in Belis, Jan; Louter, Christian (Eds.) Challenging Glass 5 (2016, June 17)

The evaluation of adaptive facades presents a challenge because there is no established evaluation strategy to systematically reach this goal and many of the available façade performance evaluation tools ... [more ▼]

The evaluation of adaptive facades presents a challenge because there is no established evaluation strategy to systematically reach this goal and many of the available façade performance evaluation tools have limited applicability for such advanced building facades. This paper presents a case study for an adaptive glass façade and evaluates its performance. The evaluation focuses mainly on pre and post construction phase of adaptive facades: The design assist phase (including the durability test, visual mockup, onsite panel mounting and weather stripping), the commissioning phase (field verification and performance testing) and the monitoring phase. The selected project is a nearly zero energy building with unique façade comprising thermal isolated glass sunshades printed with white silk screen. These louvers respond dynamically and automatically to the angle of the sun which improves the control over energy consumption, solar radiation and glare with the ability to admit natural light into the building. The paper is part of the research activities of working group 3 of the European COST Action 1403 on “Adaptive Facades “. Different methods were used for evaluation, this include: interviews with the architect, façade engineer and technical control specialist, reviews of standard and codes and a systematic process mapping. A documentation of the case study describing the post construction occupant comfort and façade operation was prepared. This paper’s audience is mainly architects, building façade engineers together with facility managers concerned with the process of design, construction and operation of adaptive glass facades. The outcome of this study identifies effective strategies for the design and performance evaluation of optimal adaptive facades. [less ▲]

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See detailConversion of visual post fire measurements into fire severity with the aid of thermo-plastic analysis for retrofitting
Molkens, Tom; Gernay, Thomas ULg; Van Coile, Ruben

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 10)

At Koksijde in Belgium a severe fire took place in an apartment building in 2015, resulting in the death of a young man and visible structural damage to four balconies. Following the fire, experts were ... [more ▼]

At Koksijde in Belgium a severe fire took place in an apartment building in 2015, resulting in the death of a young man and visible structural damage to four balconies. Following the fire, experts were mandated to assess the damage and the need for structural repair. They estimated that the balconies had to be refurbished but that there were no other structural elements affected, in particular the slab inside the apartment could be left in place with only a surface treatment and new plaster finishing. However, the floor slab in the apartment located above the fire apartment exhibited several visual indications that the fire could have had a structural impact, such as residual deformations and cracks in the tiles. This paper presents a methodology to infer the fire severity based on post-fire measurements and non-linear thermo-plastic numerical simulations. Finally, knowing the fire severity, its effect on the structure is evaluated and a reliability-based assessment is made of the residual load bearing capacity of the slab. [less ▲]

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See detailFire fragility functions for community resilience assessment
Elhami Khorasani, Negar; Gernay, Thomas ULg; Garlock, Maria

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 10)

This work provides a framework to evaluate the response of buildings in a community to fire following earthquake. As part of the framework, the paper discusses two methodologies: (1) how to develop fire ... [more ▼]

This work provides a framework to evaluate the response of buildings in a community to fire following earthquake. As part of the framework, the paper discusses two methodologies: (1) how to develop fire fragility functions; (2) how the fire fragility functions can be used in conjunction with an original fire ignition model to estimate the potential losses in a community from fire following earthquake. The paper focuses in particular on the development of fire fragility functions for an entire building to measure the probability of reaching a damage state given a fire scenario. Next, the paper proposes an ignition model to evaluate the probability of fire ignition after an earthquake. The ignition model together with fragility functions measure the probability of damage from fire following earthquake given an earthquake scenario. [less ▲]

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See detailTowards a standard measure of the ability of a structure to resist a natural fire
Gernay, Thomas ULg; Franssen, Jean-Marc ULg

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 10)

Fire brigades face a major threat when intervening in a building in fire: the possibility of structural collapse during the cooling phase of the fire, or soon thereafter. In the current approaches to ... [more ▼]

Fire brigades face a major threat when intervening in a building in fire: the possibility of structural collapse during the cooling phase of the fire, or soon thereafter. In the current approaches to structural fire engineering, the fire resistance rating (R) is generally the only measure taken into consideration to characterize the fire performance of structural elements, although this measure does not reflect the response in real fire conditions. In this work, a standard measure is proposed to characterize the ability of structural members to resist a natural fire including the decay phases. This measure yields information about the potential occurrence of delayed failure as a function of the duration of the fire before it started to decrease, whether by self-extinction or due to the action of the fire fighters. The paper presents the method to derive this new standard measure as well as results for different typologies of structural elements. Finally, the interpretation and practical consequences are discussed, in particular regarding the safety of fire fighters during an intervention. [less ▲]

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See detailCritical parameters in deriving fire fragility functions for steel gravity frames
Gernay, Thomas ULg; Elhami Khorasani, Negar; Garlock, Maria

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 10)

Fire fragility functions can be used to characterize the probabilistic vulnerability of buildings to fire in the context of urban resilience assessment. A methodology has been proposed to develop such ... [more ▼]

Fire fragility functions can be used to characterize the probabilistic vulnerability of buildings to fire in the context of urban resilience assessment. A methodology has been proposed to develop such functions for multi-story steel buildings. However, a large number of parameters with uncertainties play a role in the process of constructing the fragility functions. The goal of this research is to identify the critical parameters that most affect the global fire safety by investigating the sensitivity of the fragility functions to different input parameters. Sensitivity in parameters affecting the fire model, the heat transfer process and the thermo-mechanical response is examined. The effects of different design assumptions at the system level are also studied. The presented approach is useful for selecting the prevailing parameters in a fire reliability analysis and it provides important information for modeling tools that can be used to evaluate resilience for fire scenarios. [less ▲]

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See detailStability in Hybrid Fire Testing
Sauca, Ana ULg; Gernay, Thomas ULg; Robert, Fabienne et al

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 09)

Hybrid testing is an appealing technique to observe the behavior of an element in an experimental test while taking into account the interaction with the rest of the structure which is modelled ... [more ▼]

Hybrid testing is an appealing technique to observe the behavior of an element in an experimental test while taking into account the interaction with the rest of the structure which is modelled numerically. Being widely used in the seismic field, this technique has been recently proposed in the fire field. The purpose of this paper is to demonstrate that the loading control process may be unstable during the hybrid testing when using the methodology applied in former tests presented in the literature. The stability in the latter method depends on the stiffness ratio between the two substructures. For the purpose of discussion, a one degree-of-freedom elastic system is studied. To overcome the stability issues, a new method is presented, independent on the stiffness ratio. Finally, the hybrid testing of a 2D beam being part of a moment resisting frame is analyzed in a virtual environment (both parts being modeled numerically) using the “first generation method” and the new proposed method. [less ▲]

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See detailFire Resistance of Reinforced Concrete Columns Subjected to Standard Fire – Comparison of an Advanced and a Simplified Method
Achenbach, Marcus; Gernay, Thomas ULg; Morgenthal, Guido

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 08)

For designing concrete columns subjected to a standard fire exposure, the Eurocode permits the use of simplified or advanced calculation methods. For the designer, the question of the respective ... [more ▼]

For designing concrete columns subjected to a standard fire exposure, the Eurocode permits the use of simplified or advanced calculation methods. For the designer, the question of the respective advantages of these two types of methods arises. Which situations demand the use of an advanced method? When does a simple method provide sufficient accuracy? In this paper, laboratory tests are recalculated using Finite Element Modeling (FEM) as an advanced and Extended Zone Model (EZM) as a simple method in order to investigate these questions. The recalculations indicate that the simple EZM is of sufficient accuracy for symmetric heated columns without restraints. In contrast, the mechanical behavior of columns heated on three sides demands an advanced method such as FEM to be properly described. [less ▲]

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See detailA Stochastic Multi-scale Model For Predicting MEMS Stiction Failure
Hoang Truong, Vinh ULg; Paquay, Stéphane; Golinval, Jean-Claude ULg et al

in Proceedings of the SEM XIII International Congress and Exposition on Experimental and Applied Mechanics. (SEMXIII 2016) (2016, June 06)

Adhesion is an important phenomenon in the context of MEMS for which the surface forces become dominant in comparison with the body forces. Because the magnitudes of the adhesive forces strongly depend on ... [more ▼]

Adhesion is an important phenomenon in the context of MEMS for which the surface forces become dominant in comparison with the body forces. Because the magnitudes of the adhesive forces strongly depend on the surface interaction distances, which in turn evolve with the roughness of the contacting surfaces, the adhesive forces cannot be determined in a deterministic way. To quantify the uncertainties on the structural stiction behavior of a MEMS, this work proposes a “stochastic multi-scale methodology”. The key ingredient of the method is the evaluation of the random meso-scale apparent contact forces, which homogenize the effect of the nano-scale roughness and are integrated into a numerical model of the studied structure as a random contact law. To obtain the probabilistic behavior at the structural MEMS scale, a direct method needs to evaluate explicitly the meso-scale apparent contact forces in a concurrent way with the stochastic multi-scale approach. To reduce the computational cost, a stochastic model is constructed to generate the random meso-scale apparent contact forces. To this end, the apparent contact forces are parameterized by a vector of parameters before applying a polynomial chaos expansion in order to construct a mathematical model representing the probability of the random parameters vector. The problem of miro-beam stiction is then studied in a probabilistic way. [less ▲]

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See detailNumerical Properties of a Discontinuous Galerkin formulation for electro-thermal coupled problems
Homsi, Lina; Geuzaine, Christophe ULg; Noels, Ludovic ULg

in Papadrakakis, M.; Papadopoulos, V.; Stefanou, G. (Eds.) et al Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering, Crete Island, Greece, 5–10 June 2016 (2016, June 05)

Discontinuous Galerkin (DG) methods are attractive tools to integrate several PDEs in engineering sciences, due to their high order accuracy and their high scalability in parallel simulations. The main ... [more ▼]

Discontinuous Galerkin (DG) methods are attractive tools to integrate several PDEs in engineering sciences, due to their high order accuracy and their high scalability in parallel simulations. The main interest of this work is to derive a constant and stable Discontinuous Galerkin method for two-way electro-thermal coupling analyses. A fully coupled nonlinear weak formulation for electro-thermal problems is developed based on continuum mechanics equations which are discretized using the Discontinuous Galerkin method. Toward this end, the weak form is written in terms of energetically conjugated fields gradients and fluxes. In order to validate the effectiveness of the formulation and illustrate the algorithmic properties, a numerical test for composite materials is performed. [less ▲]

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See detailY-a-t-il des contre-indications à l'examen ENMG ?
WANG, François-Charles ULg

in Echaniz-Laguna, Andoni (Ed.) ENMG 2016 (2016, June 02)

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See detailInfluence of propeller configuration on propulsion system efficiency of multi-rotor Unmanned Aerial Vehicles
Theys, Bart; Dimitriadis, Grigorios ULg; Hendrick, Patrick et al

in Proceedings of the International Conference on Unmanned Aircraft Systems, ICUAS 2016 (2016, June)

Multi-rotor Unmanned Aerial Vehicles make use of multiple propellers, mounted on arms, to produce the required lift. This article investigates the influence on propulsion system efficiency in hover due to ... [more ▼]

Multi-rotor Unmanned Aerial Vehicles make use of multiple propellers, mounted on arms, to produce the required lift. This article investigates the influence on propulsion system efficiency in hover due to the configuration of these propellers. Influence of pusher or puller configuration of the propeller, number of blades, shape and dimensions of the arm, coaxial and overlapping propellers, is presented. A dedicated test bench that allows testing of various experimental setups is designed and built in order to realistically represent multi-rotor arms. Test results show that a two-bladed pusher configuration is most efficient and slenderness of the arm has more influence on efficiency than shape. A coaxial propulsion system approaches the efficiency of a single-prop system at high disk loadings. Finally, interference effects due to overlapping propellers are discussed. [less ▲]

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See detailUn outil e-Health pour tous ? Le cas de l'informatisation du dossier infirmier au sein d'un hôpital belge
Slomian, Cynthia ULg; Schoenaers, Frédéric ULg

in Lovis, Christian; Séroussi, Brigitte; Ugon, Adrien (Eds.) et al eSanté pour tous (2016, June)

Contexte. Les soins de santé en Belgique et ailleurs sont confrontés à deux réalités : l’augmentation de la demande de soins, d’une part, et la volonté de l’Etat de diminuer les dépenses de santé, d’autre ... [more ▼]

Contexte. Les soins de santé en Belgique et ailleurs sont confrontés à deux réalités : l’augmentation de la demande de soins, d’une part, et la volonté de l’Etat de diminuer les dépenses de santé, d’autre part. Dans ce contexte, l’e-Health est souvent présentée comme la solution qui permettra de rationaliser les moyens, mais également d’augmenter l’efficience du système. Cet article se propose d’étudier une facette de l’e-Health : l’informatisation du dossier infirmier au sein d’un hôpital belge. Méthodes. Le matériau empirique rassemble des entretiens semi-directifs (n=30), des heures d’observation du travail infirmier (n=25) ainsi que l’étude de documents organisationnels. L’analyse du matériau repose sur la sociologie de l’action organisée. Résultats. L’introduction de l’ordinateur provoque des changements, mais également la persistance de routines organisationnelles. Discussion. Les infirmières s’approprient le dossier infirmier informatisé et tentent de maximiser leur pouvoir au sein de l’organisation. Conclusion. Un outil informatique n’est jamais totalement contraignant. Les acteurs se saisissent des marges de manœuvre laissée par celui-ci pour maximiser leur pouvoir. L’appropriation contingente du dispositif est au cœur de cette démarche de changement. [less ▲]

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See detailContext-dependent feature analysis with random forests
Sutera, Antonio ULg; Louppe, Gilles; Huynh-Thu, Vân Anh ULg et al

in Uncertainty In Artificial Intelligence: Proceedings of the Thirty-Two Conference (2016) (2016, June)

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See detailA TOPSAR Processor based on the Omega-K Algorithm: Evaluation with Sentinel-1 Data
Kirkove, Murielle ULg; Orban, Anne ULg; De Rauw, Dominique ULg et al

in A TOPSAR Processor based on the Omega-K Algorithm: Evaluation with Sentinel-1 Data (2016, June)

This paper presents a processor for the TOPS (Terrain Observation by Progressive Scans) imaging mode. TOPS signals have two characteristics that make the use of Stripmap SAR processors inconvenient, i.e ... [more ▼]

This paper presents a processor for the TOPS (Terrain Observation by Progressive Scans) imaging mode. TOPS signals have two characteristics that make the use of Stripmap SAR processors inconvenient, i.e., azimuth frequency and azimuth time foldings. This paper describes a processor based on the Omega-K (Ω-k) algorithm, combined with pre-processing by frequency unfolding and post-processing by time unfolding. Raw data acquired by Sentinel-1 have been used to assess the quality of image reconstruction [less ▲]

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See detailProbabilistic reliability management approach and criteria for power system real-time operation
Karangelos, Efthymios ULg; Wehenkel, Louis ULg

in Power Systems Computation Conference (2016, June)

This paper develops a probabilistic approach for power system reliability management in real-time operation where risk is a product of i) the potential occurrence of contingencies, ii) the possible ... [more ▼]

This paper develops a probabilistic approach for power system reliability management in real-time operation where risk is a product of i) the potential occurrence of contingencies, ii) the possible failure of corrective (i.e., post-contingency) control and, iii) the socio-economic impact of service interruptions to end-users. Stressing the spatiotemporal variability of these factors, we argue for reliability criteria assuring a high enough probability of avoiding service interruptions of severe socio-economic impact by dynamically identifying events of nonnegligible implied risk. We formalise the corresponding decision making problem as a chance-constrained two-stage stochastic programming problem, and study its main features on the single area IEEE RTS-96 system. We also discuss how to leverage this proposal for the construction of a globally coherent reliability management framework for long-term system development, midterm asset management, and short-term operation planning. [less ▲]

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See detailPerformance evaluation of an Organic Rankine Cycle (ORC) connected to two-phase closed thermosyphons
Le, Van Long ULg; Declaye, Sébastien ULg; Dumas, Xavier et al

in PROCEEDINGS OF ECOS 2016 (2016, June)

This paper aims at evaluating the performance of a waste heat-to-power plant using an organic Rankine cycle (ORC) connected to two-phase closed thermosyphons (or gravity-assisted heat pipes or wickless ... [more ▼]

This paper aims at evaluating the performance of a waste heat-to-power plant using an organic Rankine cycle (ORC) connected to two-phase closed thermosyphons (or gravity-assisted heat pipes or wickless heat pipes). The heat exchanger, made up of two-phase closed thermosyphons, is used for transferring heat from exhaust stream to ORC working fluid. In practice, a hot oil loop or a pressurized hot water loop or a saturated steam loop or even a direct evaporator is often used to transfer heat from heat source to ORC system. However, installing a heat exchanger directly in the hot gas paths of ORC system evokes the concerns for the flammability and/or toxicity of organic working fluids especially when the heat source has a relative high temperature. Also the use of an intermediate heat carrier loop such as thermal oil or saturated steam or pressurized water loop is relatively expensive and involves installation of relatively heavy components. A priori, the use of two-phase closed thermosyphons for capturing and transferring heat from a waste heat source to organic working fluid is less expensive than the use of an intermediate heat transfer loop and eliminates safety concerns as in the case of direct installation of an ORC evaporator in the hot gas paths. [less ▲]

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See detailDesign and Evaluation of a High-Density Energy Storage Route with CO2 Re-Use, Water Electrolysis and Methanol Synthesis
Léonard, Grégoire ULg; Giulini, Davide; Villarreal-Singer, Diego

in Proceedings of the 26th European Symposium on Computer Aided Process Engineering - ESCAPE 26 (2016, June)

The energy transition corresponding to more electricity generation from variable and decentralized renewable energy sources requires the development of electricity storage technologies ranging from ... [more ▼]

The energy transition corresponding to more electricity generation from variable and decentralized renewable energy sources requires the development of electricity storage technologies ranging from seconds to seasons. The power-to-fuel process provides a way to store electricity as a liquid energy vector, leading to high energy density and cheap long-term storage at ambient conditions. In the present work, we study the powerto- methanol process combining CO2 capture, water/CO2 co-electrolysis and methanol synthesis. An Aspen Plus model focussing on the electrolysis and methanol synthesis sub-processes is presented. The energy conversion efficiency is improved from 40.1 to 53.0 % thanks to heat integration using the pinch method. Further works include the experimental demonstration of this technology as well as the development of control strategies for its regulation. [less ▲]

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See detailLe marquage et les soins vétérinaires appliqués aux camélidés d'après la documentation papyrologique grecque d’Égypte
Ricciardetto, Antonio ULg

in Gitton-Ripoll, Valérie (Ed.) La trousse du vétérinaire dans l'Antiquité et au Moyen Âge. Instruments et pratiques (2016, June)

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See detailModifying Indoor Facilities Appropriate to Children
Jidovtseff, Boris ULg; Delvaux, Anne ULg; Mornard, Manhattan ULg et al

in Book of abstracts AISEP 2016 (2016, June)

Introduction Physical literacy development during childhood is critical not only to favor sport performance outcomes but also to develop long term physical activity. It’s very important for children to ... [more ▼]

Introduction Physical literacy development during childhood is critical not only to favor sport performance outcomes but also to develop long term physical activity. It’s very important for children to move in a thinking way. Diversified activities are important to develop a large panel of fundamental motor skills and to stimulate perception. It is important for children to move, but it has to be done in a thinking way. Focus on inquiry With young children it is important to maximize active time, to develop fundamental motor skills and perception, to take into account inter-individual differences, to favor enjoyment, self-confidence and to guarantee optimal security. Most of these pedagogical challenges can be reached by appropriate instruction and by an adapted environment. Contribution There is clear evidence that modifying exercise facilities influence children’s behaviour with consequences for motivation, activity level and motor development. For 25 years a reflexive approach has been used at CEReKi (Liège, Belgium) in order to determine how indoor facilities can be modified with the aim to meet children needs and to favor motor development. Attractive circuits have been developed to stimulate specific motor skills (gymnastic, athletic or ball circuits). They were created to afford action possibilities and challenges for children to explore their own abilities for exercise. According to the children’s age and level of ability different pedagogical conditions can be provided: spontaneous play, guided discovery or structured games. Circuits have to be organised in such a way that children can do most exercises on their own. The arrangement of equipment offers multiple possibilities for movement, favouring active discovery for all children. The autonomy of children allows the teacher to move throughout the circuit and assist children by scaffolding their learning. Conclusion Our experience confirms that modifying indoor facilities is relevant for 3 to 8 years old children activities. [less ▲]

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See detailOn the modeling of MMC for use in large scale dynamic simulations
Freytes, Julian; Papangelis, Lampros ULg; Saad, Hani et al

in Proceedings of the 19th PSCC (2016, June)

This paper focuses on simplified models of the Modular Multilevel Converter suitable for large-scale dynamic studies, in particular simulations under the phasor approximation. Compared to the existing ... [more ▼]

This paper focuses on simplified models of the Modular Multilevel Converter suitable for large-scale dynamic studies, in particular simulations under the phasor approximation. Compared to the existing literature, this paper does not a priori adopt the modeling approach followed for the original twolevel or three-level Voltage Source Converter. On the contrary, a model is derived following a physical analysis that preserves its average internal dynamic behavior. An equivalent control structure is proposed and various alternatives are highlighted. The proposed model with its controllers has been implemented in a phasor simulation software and its response has been validated against a detailed Electromagnetic Transient model. Finally, an illustrative example is presented with the application of the proposed model on a large grid consisting of AC areas interconnected with a multi-terminal DC grid. [less ▲]

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See detailMitigation of the torsional flutter phenomenon of bridge deck section during a lifting phase
Andrianne, Thomas ULg; De Ville De Goyet, Vincent ULg

in Mitigation of the torsional flutter phenomenon of bridge deck section during a lifting phase (2016, June)

This paper presents a complete analysis of the aeroelastic behaviour of a deck section during the construction stage of the Third Bosphorus Bridge in Istanbul, Turkey. The combination of the low torsional ... [more ▼]

This paper presents a complete analysis of the aeroelastic behaviour of a deck section during the construction stage of the Third Bosphorus Bridge in Istanbul, Turkey. The combination of the low torsional stiffness along the vertical axis and the unstable aerodynamic shape of the suspended deck section led to a torsional flutter instability for a low wind speed (9.6 m/s). This low critical wind speed was obviously very likely to occur on the site of construction, so that mitigation actions were be implemented. It was decided to cover partially the sides of the deck section in order to modify adequately its aerodynamic shape. It is demonstrated that the proposed aerodynamic counter-measures increase the critical torsional flutter wind speed up to 39.5 m/s (worst configuration), which is acceptable for the construction phase of the bridge. The proposed mitigation solution was implemented and no torsional oscillations were observed. [less ▲]

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See detailÉtude statistique de la syntaxe des lexèmes _chetif_, _dolent_, _las_ et _maleüré_ en français médiéval
Mazziotta, Nicolas ULg

in Mayaffre, Damon; Poudat, Céline; Vanni, Laurent (Eds.) et al JADT 2016 - Proceedings of the 13th International Conference on Statistical Analysis of Textual Data (2016, June)

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See detailA Gaussian mixture approach to model stochastic processes in power systems
Gemine, Quentin ULg; Cornélusse, Bertrand ULg; Glavic, Mevludin ULg et al

in Proceedings of the 19th Power Systems Computation Conference (PSCC'16) (2016, June)

Probabilistic methods are emerging for operating electrical networks, driven by the integration of renewable generation. We present an algorithm that models a stochastic process as a Markov process using ... [more ▼]

Probabilistic methods are emerging for operating electrical networks, driven by the integration of renewable generation. We present an algorithm that models a stochastic process as a Markov process using a multivariate Gaussian Mixture Model, as well as a model selection technique to search for the adequate Markov order and number of components. The main motivation is to sample future trajectories of these processes from their last available observations (i.e. measurements). An accurate model that can generate these synthetic trajectories is critical for applications such as security analysis or decision making based on lookahead models. The proposed approach is evaluated in a lookahead security analysis framework, i.e. by estimating the probability of future system states to respect operational constraints. The evaluation is performed using a 33-bus distribution test system, for power consumption and wind speed processes. Empirical results show that the GMM approach slightly outperforms an ARMA approach. [less ▲]

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See detailDirect control service from residential heat pump aggregation with specified payback
Georges, Emeline ULg; Cornélusse, Bertrand ULg; Ernst, Damien ULg et al

in Proceedings of the 19th Power Systems Computation Conference (PSCC) (2016, June)

This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service is defined by a 15 minute power modulation, upward or ... [more ▼]

This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service is defined by a 15 minute power modulation, upward or downward, followed by a payback of one hour and 15 minutes. The service modulation is relative to an optimized baseline that minimizes the energy costs. The potential amount of modulable power and the payback effect are computed by solving mixed integer linear problems. Within these problems, the building thermal behavior is modeled by an equivalent thermal network made of resistances and lumped capacitances whose parameters are identified from validated models. Simulations are performed on 100 freestanding houses. For an average 4.3 kW heat pump, results show a potential of 1.2 kW upward modulation with a payback of 600 Wh and 150 Wh of overconsumption. A downward modulation of 500 W per house can be achieved with a payback of 420 Wh and 120 Wh of overconsumption. [less ▲]

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See detailMot à mot, brin par brin : les suites [Nom préposition Nom] comme indices de littérarité ?
Purnelle, Gérald ULg; Magri, Véronique; Legallois, Dominique

in Mayaffre, Damon; Poudat, Céline; Vanni, Laurent (Eds.) et al Statistical Analysis on Textual Data - Proceedings of 13th International Conference on Statistical Analysis of Textual Data (2016, June)

For the JADT 2012, we applied the text pattern theory to Noun-preposition-Noun (NpN) sequences, where both nouns surrounding the preposition are identical. Our working corpus was composed of texts from ... [more ▼]

For the JADT 2012, we applied the text pattern theory to Noun-preposition-Noun (NpN) sequences, where both nouns surrounding the preposition are identical. Our working corpus was composed of texts from the four main literary genres, memoirs (109 texts), novels (740 texts), poetry (191 texts) and theater (210 texts), 85 million words, sampled out of Frantext, a categorized database. That exploratory research allowed us to pinpoint the specific place of the NpN sequence, between language and discourse, its blooming into a full discursive pattern, able to produce a stylistic effect linked to lexical innovation, as well as its possible use as a generic litterarity marker. This paper aims at pursuing the work by extending the corpus and proposing new contrastive studies, showing the role of the NpN sequence as a litterarity marker. [less ▲]

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See detailUpdating Failure Probability Of A Welded Joint In Offshore Wind Turbine Substructures
Mai, Anh Quang ULg; Sørensen, John D.; Rigo, Philippe ULg

in The 35th International Conference on Ocean, Offshore and Arctic Engineering (OMAE) (2016, June)

For offshore wind turbines, the support structure contributes with a significant part to the Levelized Cost Of Energy (LCOE). LCOE is the total cost to build and operate a whole offshore wind turbine ... [more ▼]

For offshore wind turbines, the support structure contributes with a significant part to the Levelized Cost Of Energy (LCOE). LCOE is the total cost to build and operate a whole offshore wind turbine structure over its lifetime divided by the total energy output of the wind turbine over that lifetime. That total expected cost of operation & maintenance may be lowered by application of reliability- and risk-based maintenance strategies and updating of the reliability based on e.g. inspections performed during the design lifetime. Updating the reliability (or alternatively the failure probability) of a welded joint can theoretically be done using Bayesian updating. However, for tubular joints in offshore wind turbine substructure when considering a two dimensional crack growth and a failure criterion combined brittle fracture and material strength, the updating is quite complex due to the wind turbine loading obtained during operation. This paper considers how the reliability (or the probability of failure) of welded steel details can be updated in the case where the fatigue failure is modelled by a fracture mechanics approach and a Failure Assessment Diagram (FAD) is used to define a limit state equation. Besides, it is shown how the probability of failure of fatigue critical joints can be updated for various inspection scenarios. A two dimensional bi-linear model is considered for the crack growth. Calculation of the crack depth and the crack length are coupled. The stress intensity factor is calculated following the sophisticated procedure in BS 7910:2005. The initial crack size, the yield and ultimate strengths of steel, the fracture toughness, the stress intensity factor, and the stress-ranges are considered as uncertain and modelled by random variables. The probability of detection is used to account for uncertainty in crack inspections. By using Monte Carlo simulations, stress-range histories are generated randomly and together with the calculated stress intensity factors used to check the limit state condition using the FAD approach. The probability of failure updating is done for three inspection scenarios: No crack detected; Crack detected and repaired; Crack detected but not repaired. The paper presents illustrative results for offshore wind applications for the three scenarios, including comparisons of application of the FAD approach for modelling the limit state equation with a ‘conventional’ approach where it is assumed that failure happens when crack-depth reaches the plate thickness or the stress intensity factor is equal to or larger than the fracture toughness of the material. Finally, it is discussed how application of the updating procedure can be used for inspection planning for offshore wind turbine support structures, and thus also for reducing the required safety factors at the design stage. [less ▲]

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See detailInfluence of the inter‐stage coupling flexibility on the dynamics of multi‐stage rotors
Nyssen, Florence ULg; Golinval, Jean-Claude ULg

in Proceedings of the ASME Turbo Expo 2016 (2016, June)

In this work, a characterization of the inter-stage coupling in a one-piece multi-stage bladed structure is performed. More particularly, the effect of the inter-stage coupling flexibility on the mode ... [more ▼]

In this work, a characterization of the inter-stage coupling in a one-piece multi-stage bladed structure is performed. More particularly, the effect of the inter-stage coupling flexibility on the mode-shapes is evaluated. To this purpose, the MAC matrix between the mono-stage and multi-stage modes is computed for different drum Young’s modulus of the inter-stage coupling. In parallel, the strain energy located in the blades and in the connecting structure is computed for different levels of inter-stage coupling. This enables to establish a criterion to determine when a multi-stage finite element analysis is necessary instead of only computing the different mono-stage models separately. This criterion is based on the localization of the energy in the structure. Numerical analyses are performed on a two-stages academic bladed structure. [less ▲]

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See detailDevelopment of a semi-analytical model of volumetric expander for system-level simulation.
Oudkerk, Jean-François ULg

in Proceedings of ECOS 2016 (2016, June)

Organic Rankine cycles are particularly well suited for recovering energy from low-grade heat sources, such as industrial waste, engine exhaust gas or solar concentrated power. In ow-capacity systems ... [more ▼]

Organic Rankine cycles are particularly well suited for recovering energy from low-grade heat sources, such as industrial waste, engine exhaust gas or solar concentrated power. In ow-capacity systems, volumetric expanders are often preferred to turbomachines because of their reliability, robustness, low rotational speed and their ability to handle high pressure ratios… Different types of machines have been investigated and successfully tested by the uthors and tools have been developed in order to analyse experimental data. Semi-empirical odel was built to analyse losses, detect potential improvement and simulate performances. This paper present a simple and fastcomputing semi-analytical model useful for simulate dynamic system integrating volumetric expander. This model is validated on experimental data and compare to black-box model. [less ▲]

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See detailDas MOBAK-Netzwerk: Kulturvergleichende Perspektive aus acht europäischen Ländern
Scheuer, Claude; Cloes, Marc ULg; Colella, Dario et al

in Kaboth, Holger; Heim, Christopher; Prohl, Robert (Eds.) Bildungsforschung im Sport (2016, May 27)

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See detailLes problématiques de la rénovation du stock bâti dans la ville de demain : résultats d’une étude initiale en Belgique.
Ruellan, Guirec ULg

in 34èmes Rencontres Universitaires de Génie Civil de l'AUGC, Liège, 25 au 27 mai 2016 (2016, May 25)

Pour atteindre les objectifs énergétiques de l’Union Européenne pour 2050, et plus largement les objectifs fixés à la dernière COP, le secteur de la construction et de l’habitat doit opérer sa mue vers un ... [more ▼]

Pour atteindre les objectifs énergétiques de l’Union Européenne pour 2050, et plus largement les objectifs fixés à la dernière COP, le secteur de la construction et de l’habitat doit opérer sa mue vers un modèle plus durable. En Belgique, cela passe par la rénovation et l’amélioration des performances du stock bâti existant. La présente étude porte sur l’identification des différents enjeux (environnementaux, économiques et sociaux) liées à la rénovation en Belgique et tente d’objectiver les barrières (de financement, de communication et de réglementation) à une augmentation du taux de rénovation, à travers une revue de littérature des différentes études et projets portant sur ce domaine en Belgique. Ces résultats initiaux devront permettre ultérieurement la conduite des recherches approfondies visant à la modélisation des effets de plusieurs stratégies possibles d’augmentation du taux de rénovation. [less ▲]

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See detailDenCity: Zero Energy Light Weight Construction Households for Urban Densification
Amer, Mohamed ULg; Attia, Shady ULg

in Rencontres Universitaires de Génie Civil de l'AUGC (2016, May 25)

This paper is a part of an ongoing research in the field of sustainable urban densification through providing innovative solutions for zero energy light weight construction. The focus aim of this research ... [more ▼]

This paper is a part of an ongoing research in the field of sustainable urban densification through providing innovative solutions for zero energy light weight construction. The focus aim of this research is to identify the gaps in the construction solutions for roof stacking, to feed in the innovation pipeline of the European construction landscape in the coming years. This paper presents a comprehensive review of different case studies and efforts in the field of roof raising and its repetition potentials. Based on a structured review, 8 different cases from three different European countries were sorted, placing a variety of methods in comparison with each other. The main contribution of this review lies in the analyses of the existing information in this field and the classification of the different validated methods and approaches that has been used. Finally, despite the existing challenges, it was found that the concept of roof stacking can be widely spread and applied in different contexts. Future research is going to investigate possible solution and to formulate structured scientific approaches to widen its application. [less ▲]

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See detailLes lésions musculo-squelettiques de l’adolescent sportif
Kaux, Jean-François ULg

in 14èmes Journées de l’Enseignement Post-Universitaire de la Faculté de Médecine de Liège (2016, May 21)

Le développement des activités sportives augmente la fréquence des lésions musculo-squelettiques de l’adolescent. Ces lésions dépendent non seulement du mécanisme mais également de l’âge du sportif et de ... [more ▼]

Le développement des activités sportives augmente la fréquence des lésions musculo-squelettiques de l’adolescent. Ces lésions dépendent non seulement du mécanisme mais également de l’âge du sportif et de sa maturation osseuse, particulièrement des noyaux d’ossification. Les aphophysoses, ostéochondroses ou ostéodystrophies se manifestent par une douleur au niveau de l’insertion tendineuse sur le noyau d’ossification secondaire en croissance. Elles sont souvent provoquées par des contraintes en traction-cisaillement chez des enfants sportifs entre 3 et 16 ans. L’excès pondéral constitue également un facteur de risque. La guérison spontanée s’observe généralement après trois à 12, voire 18 mois d’évolution. La maladie de Sever est l’ostéodystophie du pied la plus fréquente ; elle touche le noyau postérieur du calcanéum, qui apparaît entre sept et dix ans et qui fusionne à la fin de la puberté (16–18 ans) et sur lequel s’insèrent le tendon d’Achille et le court fléchisseur plantaire. Les contraintes en traction et compression (réception de saut) sont importantes à ce niveau surtout chez les sportifs de sept à 15 ans pratiquant diverses impulsions (basket-ball, volley-ball, saut en longueur. . . ). La talalgie se manifeste lors de la pratique sportive. La douleur est bilatérale dans 60% des cas. Il faut rechercher des troubles de statique plantaire (pieds creux) régulièrement associés à la maladie de Sever. Le bilan radiologique reste souvent décevant et peu spécifique. Le diagnostic différentiel doit s’établir avec une tendinopathie achilléenne, une fracture du calcaneus, un kyste osseux, un ostéome ostéoïde, une ostéomyélite ou une éventuelle enthésopathie (spondylarthropathie). La base du traitement est le repos sportif en phase algique, l’usage de la cryothérapie, le port de talonnettes amortissantes ou encore la prise temporaire d’AINS (ibuprofène). Au niveau du genou, l’apophysose de croissance la plus fréquente est la maladie d’Osgood-Schlatter qui est plus fréquente chez les adolescents pratiquant des sports de sauts. Au niveau du bassin tous les noyaux d’ossifications peuvent être atteints et même être le site de fractures-avulsions lors de contractions musculaires excessives ou brutales car le cartilage de croissance présente une faiblesse locale par rapport aux structures musculo-tendineuses. L’ostéochondrite disséquante correspond à un noyau osseux séparé du corps de l’os et recouvert de cartilage normal ; localisée à la partie supéromédiale du talus ou au niveau des condyles fémoraux. Elle est souvent asymptomatique, voire entraine une discrète limitation douloureuse de la mobilisation mais entraine une douleur à la palpation locale. Elle nécessite cependant un traitement adéquat. En cas de lésion peu ou pas évolutive, une surveillance radiologique (IRM / arthroscanner) est suffisante. Chez le très jeune adolescent une immobilisation plâtrée de six semaines permettrait la fusion du noyau (au niveau du dôme talien). L’arthroscopie sera justifiée en cas de séquestre osseux afin de l’extraire, et ce, avec de bons résultats postopératoires. L’ostéosynthèse d’un noyau volumineux peut être également indiquée, les résultats restant plus aléatoires. En conclusion, la pathologie traumatique ou microtraumatique de l’adolescent sportif n’est pas rare et ne doit jamais être négligée. Toute douleur exige une exploration radiologique comparative afin de poser un diagnostic précis et d’entreprendre un traitement adéquat, le plus souvent conservateur. [less ▲]

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See detailE-ELT/METIS
Brandl, B.; Quanz, S.; Feldt, M. et al

in Simon, R.; Schaaf, R.; Stutzki, J. (Eds.) Conditions and Impact of Star Formation (2016, May 20)

The Mid-infrared E-ELT Imager and Spectrograph (METIS) will be one of the first three scientific instruments on the European Extremely Large Telescope (E-ELT). It will be the only instrument to cover the ... [more ▼]

The Mid-infrared E-ELT Imager and Spectrograph (METIS) will be one of the first three scientific instruments on the European Extremely Large Telescope (E-ELT). It will be the only instrument to cover the thermal/mid-infrared wavelength range from 3-19 μm. METIS offers a number of scientifically important observing modes, including diffraction-limited imaging, low resolution slit spectroscopy, coronagraphy, and high resolution (R ˜ 100,000) integral field spectroscopy at very high sensitivity. This paper gives a brief summary of METIS and focuses on its unique discovery space in the area of protoplanetary disks, where METIS is quite complementary to ALMA and JWST. [less ▲]

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See detailGestion du risque d’érosion côtière en Côte d’Ivoire : Cas du déguerpissement dans la commune de Port-Bouët à Abidjan
Comoe, Raymond; Ozer, Pierre ULg

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

L’Etat de Côte d’Ivoire a décidé, depuis 2011, de faire déguerpir les populations des zones à risques du District Autonome d’Abidjan afin de réduire les impacts des catastrophes naturelles. La dernière ... [more ▼]

L’Etat de Côte d’Ivoire a décidé, depuis 2011, de faire déguerpir les populations des zones à risques du District Autonome d’Abidjan afin de réduire les impacts des catastrophes naturelles. La dernière vaste opération de déguerpissement concerne l’assainissement du littoral dans la commune de Port-Bouët menacé, selon les autorités, par l’avancée de la mer. [...] [less ▲]

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See detailDémarrage et longueur de la saison de pluies dans la région de Kinshasa et risques induits
Makanzu Imwangana, Fils; Phuati, Giscard; Ozer, Pierre ULg et al

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

La détermination et la prévision du démarrage de la saison de pluies sont des questions cruciales à travers la RDC en général et en particulier dans l’hinterland de la ville de Kinshasa étant donné que ... [more ▼]

La détermination et la prévision du démarrage de la saison de pluies sont des questions cruciales à travers la RDC en général et en particulier dans l’hinterland de la ville de Kinshasa étant donné que l’agriculture y est pluviale. Elles permettent de déterminer le calendrier agricole, particulièrement le semis, et influence le rendement. La question qui se pose toujours est celle de savoir s’il y a un changement climatique dans la région de Kinshasa qui se traduirait par la variation de la saison des pluies de 1961 à 2010. Et si c’est le cas, quels en sont les impacts sur l’activité agricole et autres ? Cette étude mène une analyse de la variabilité interannuelle et décennale de la saison des pluies à partir de deux séries chronologiques dans la région de Kinshasa. [...] [less ▲]

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See detailPlace des pertes et préjudices liés aux changements climatiques dans les accords internationaux
Perrin, Dominique ULg; Ozer, Pierre ULg

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

Pour les pays les plus vulnérables, les « pertes et préjudices » (traduit de l’anglais « Loss and damage ») causés par les changements climatiques sont une question cruciale. Il n’existe pas de définition ... [more ▼]

Pour les pays les plus vulnérables, les « pertes et préjudices » (traduit de l’anglais « Loss and damage ») causés par les changements climatiques sont une question cruciale. Il n’existe pas de définition convenue des « pertes et préjudices », mais l’expression fait globalement référence à toute une série de dommages subis en raison du changement climatique et ne pouvant pas être évités par des efforts d’atténuation ou d’adaptation. La question est devenue l’un des principaux enjeux de la conférence des parties (COP) à la Convention-cadre des Nations Unies sur les changements climatiques (CCNUCC). Le récent « Accord de Paris » adopté en décembre 2015 lors de la COP21 de la CCNUCC a ouvert de nouvelles pistes pour la prise en considération de cette question. L’objectif de cet exposé introductif au colloque est bien de dresser un état des lieux complet sur les enjeux complexes liés à la prise en compte des « pertes et préjudices », tant sur les aspects scientifiques relevés par le Groupe d'experts intergouvernemental sur l'évolution du climat (GIEC) que sur les aspects économiques, sociaux et géopolitiques. [less ▲]

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See detailCap-Haïtien ou comment construire le risque d’inondations en une décennie.
Gracius, Gracia Joseph; Ozer, Pierre ULg

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

Cap-Haïtien, ville située au Nord d’Haïti, connait une multiplication sans précédent des inondations. Alors que certains observateurs sont tentés de blâmer les conséquences du changement climatique, nous ... [more ▼]

Cap-Haïtien, ville située au Nord d’Haïti, connait une multiplication sans précédent des inondations. Alors que certains observateurs sont tentés de blâmer les conséquences du changement climatique, nous tentons ici de démontrer que l’absence totale d’aménagement du territoire, la dégradation de l’environnement, l’inexistence de bonne gouvernance et l’exode rural sont les principaux ingrédients de la création d’un risque jadis exceptionnel. Cette recherche a pour objectif d’analyser l’évolution de l’extension urbaine dans deux milieux humides (la rivière Haut-du-Cap et la mangrove à Petite-Anse) de 2004 à 2016 et d’évaluer la perception du risque d’inondation par les populations locales. [...] [less ▲]

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See detailLa responsabilité climatique dans les défis urbains contemporains: évaluation et mise en contexte pour la ville de Bujumbura, Burundi
Nibigira, Léonidas ULg; Ozer, Pierre ULg; Havenith, Hans-Balder ULg

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

A Bujumbura, la capitale du Burundi, les préjudices liés aux risques naturels deviennent de plus en plus une réalité quotidienne. Les cas les plus ressentis sont ceux liés aux inondations, aux glissements ... [more ▼]

A Bujumbura, la capitale du Burundi, les préjudices liés aux risques naturels deviennent de plus en plus une réalité quotidienne. Les cas les plus ressentis sont ceux liés aux inondations, aux glissements de terrain et à l'érosion. Les épidémies relatives aux conditions sanitaires précaires deviennent de plus en plus récurrentes. [...] [less ▲]

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See detailPerceptions, des autorités nationales aux petits producteurs locaux, des changements climatiques en Equateur
Ozer, Pierre ULg; Perrin, Dominique ULg

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

Lors de chaque conférence des parties (COP) à la Convention-cadre des Nations Unies sur les changements climatiques (CCNUCC), la question de l’adaptation des pays les plus vulnérables aux conséquences des ... [more ▼]

Lors de chaque conférence des parties (COP) à la Convention-cadre des Nations Unies sur les changements climatiques (CCNUCC), la question de l’adaptation des pays les plus vulnérables aux conséquences des dérèglements climatiques est incontournable. En 2009, lors de la COP15 de Copenhague, les pays développés dont la responsabilité historique des émissions de gaz à effet de serre est avérée se sont engagés à consacrer annuellement 100 milliards d’USD à partir de 2020 pour aider les pays en développement à réduire leurs émissions et s’adapter aux effets des changements climatiques. D’ici là, les pays du Nord se doivent de mettre en place des projets d’assistance aux pays du Sud sur cette thématique. Dans ce cadre, la Wallonie a lancé un programme de solidarité internationale « climat » dans le cadre d’un développement durable des pays partenaires du Sud. [...] [less ▲]

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See detailLe Criquet pèlerin sera-t-il le déclencheur de l’effondrement de l’Afrique de l’Ouest ?
Diallo, Youssouf; Sory, Cisse; Ozer, Pierre ULg

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

Situé au cœur de l’Afrique de l’Ouest, le Mali est confronté ces dernières années à une succession de crises profondes : dégradation des conditions climatiques et environnementales, précarisation ... [more ▼]

Situé au cœur de l’Afrique de l’Ouest, le Mali est confronté ces dernières années à une succession de crises profondes : dégradation des conditions climatiques et environnementales, précarisation croissante de la sécurité alimentaire, développement de mouvements armés et terroristes dans le pays, instabilité institutionnelle, etc. Aussi, à l’instar de plusieurs pays de la région, le Mali fait périodiquement face aux invasions du Criquet pèlerin, Schistocerca gregaria (Forksål, 1775) (Orthoptera: Acrididae). Cet insecte redoutable est capable de passer d’une forme solitaire inoffensive à une forme grégaire vorace en formant des essaims et des bandes larvaires qui s’attaquent aux cultures et pâturages en provoquant des dégâts importants. [...] [less ▲]

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See detailImpact de la vulnérabilité et de la résilience aux changements environnementaux sur la mobilité en Afrique de l'Ouest
Zickgraf, Caroline ULg; Vigil Diaz Telenti, Sara ULg; de Longueville, Florence et al

in Ginesu, Sergio; Ozer, André; Ozer, Pierre (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques (2016, May 19)

Du Sahel à la zone côtière, l’Afrique de l'Ouest connaît une variété de changements environnementaux résultant tant de processus lents que de chocs soudains. Ces changements influencent significativement ... [more ▼]

Du Sahel à la zone côtière, l’Afrique de l'Ouest connaît une variété de changements environnementaux résultant tant de processus lents que de chocs soudains. Ces changements influencent significativement les schémas de migration de populations dans et hors de l'Afrique de l'Ouest. Dans cette région où les ressources naturelles constituent la base des moyens de subsistance et de la sécurité alimentaire (pêche et agriculture), la relation entre les changements environnementaux et les vulnérabilités socio-économiques est particulièrement préoccupante. [...] [less ▲]

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See detailEvolution récente du trait de côte dans le Golfe de Guinée : Exemples du Togo et du Bénin
Ozer, Pierre ULg; Hountondji, Yvon-Carmen; de Longueville, Florence

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

L’interface terre-mer est un environnement extrêmement fragile. De par le monde, les littoraux sont menacés par une multitude de facteurs parfois naturels et le plus souvent anthropiques. Ainsi, aux ... [more ▼]

L’interface terre-mer est un environnement extrêmement fragile. De par le monde, les littoraux sont menacés par une multitude de facteurs parfois naturels et le plus souvent anthropiques. Ainsi, aux perturbations locales occasionnées aux zones côtières par les infrastructures portuaires, les barrages, les prélèvements de sédiments à même la plage ou encore l’extension urbaine, s’ajoutent les conséquences globales des changements climatiques, dont l’élévation certaine du niveau des océans et l’amplification probable de conditions météo-marines dévastatrices. Cet article évalue la récente évolution du trait de côte au Togo et au Bénin où plusieurs études localisées démontrent que les plages sableuses connaissent des modifications (accumulation ou érosion) majeures ces dernières décennies. Dans le but d’avoir une vision globale de la dynamique côtière sur les 170 kilomètres de plages de ces deux pays d’Afrique de l’Ouest, des images satellitaires à haute définition spatiale disponibles en open access sur Google Earth sont utilisées de manière diachronique. [...] [less ▲]

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See detailFUNCTIONAL SPECIFICATION METHODOLOGY FOR AN ARCHITECTURAL MODELER SUPPORTING A MODULAR CONSTRUCTIVE SYSTEM
Boulanger, Christelle ULg; Rahhal, Anabelle ULg; Delfosse, Vincent ULg et al

in Design2016 (2016, May 16)

This article presents a methodological approach which helped the software development of an architectural modeler that aims to support the life cycle of buildings with a modular construction system. The ... [more ▼]

This article presents a methodological approach which helped the software development of an architectural modeler that aims to support the life cycle of buildings with a modular construction system. The modeler assists the building composition processes, the production of useful documents like drawing plans, quantities and specifications, and the evaluation of the thermal performance of the building at any phase of its design. Conducted within a multidisciplinary team of architects engineers, computer engineers and ergonomists, this methodology is based on a constant interaction between the various skills, so that the different perspectives are systematically integrated into the decision process. The methodology is based on the analysis of three fields of functions (composition - production and evaluation) which are considered simultaneously through a theoretical framework stemming from ergonomics: Activity Theory [Engeström 1987]. At first, the software development context is presented. Then, the choice of the Activity Theory as a framework for the analysis will be motivated. The next section relates the multiple concepts of the methodology to each others, in order to identify the principles as well as the inputs and the outputs. Each step in its implementation is then described, followed by the results in terms of the software interface. Finally, the discussion that will follow will consider the contributions and limitations of this methodological approach in the understanding of a system, in order to offer an efficient IT support. [less ▲]

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See detailCombined Centralized and Local Voltage correction in Active Distribution Network
Soleimani Bidgoli, Hamid ULg

in Combined Centralized and Local Voltage correction in Active Distribution Network (2016, May 12)

This paper presents a two-level real-time voltage control scheme to address the voltage violations in distribution grids hosting a significant number of Dispersed Generation Units (DGUs). The proposed ... [more ▼]

This paper presents a two-level real-time voltage control scheme to address the voltage violations in distribution grids hosting a significant number of Dispersed Generation Units (DGUs). The proposed scheme consists of a centralized and a local reactive power control. The local control provides fast response after a disturbance, reducing its impact and enhancing voltage quality. The centralized control relies on Model Predictive Control (MPC). It uses measurements collected throughout the network to bring the voltages inside desired limits. To do so, it adjusts in a coordinated way the reactive power set-points of the DGUs taking into account the local controls. The control method effectiveness has been evaluated on a 75-bus 11-kV test system hosting 22 DGUs. [less ▲]

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See detailCentralized Model Predictive Control of Multi-Terminal Direct Current Grids
Papangelis, Lampros ULg

in Proc. of the 8th IEEE Benelux Young Researchers Symposium 2016 (2016, May 12)

This work describes a centralized control for Multi-Terminal Direct Current (MTDC) grids. It is based on Model Predictive Control (MPC) whose aim is to satisfy a desired schedule, while avoiding or ... [more ▼]

This work describes a centralized control for Multi-Terminal Direct Current (MTDC) grids. It is based on Model Predictive Control (MPC) whose aim is to satisfy a desired schedule, while avoiding or correcting any system limit violation. The central controller collects voltage and power measurements from the converters of the system in regular intervals and sends back converter power setpoints. The latter are calculated by solving a quadratic programming problem subject to linear constraints and using a simplified model for the DC system. In addition, the overall MTDC grid control structure including the local and the centralized controllers is described. [less ▲]

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See detailOn the Laser Cladding of Ti Alloy Ti-6Al-4V with Low Laser Power
Mertens, Anne ULg; Paydas, Hakan ULg; Tchuindjang, Jérôme Tchoufack ULg et al

in Ventakesh, V.; Pilchak, A.L.; Allison, J.E. (Eds.) et al Proc. of the 13th World Conference on Titanium (2016, May 06)

Laser cladding is an economic layer-by-layer near-net-shape process for the production and the repair of metallic parts. In this process, a metallic powder is projected onto a substrate while being molten ... [more ▼]

Laser cladding is an economic layer-by-layer near-net-shape process for the production and the repair of metallic parts. In this process, a metallic powder is projected onto a substrate while being molten by a laser beam. Laser sources with fairly high power – i.e. typically 2kW − are often used to ensure short building times and high productivity. However, this approach has limitations. Indeed, it is very difficult to produce thin walls at high laser power. Moreover, an increase of the incident energy may give rise to a relatively coarser microstructure, and this will in turn affect the mechanical properties of the component. In order to address these issues, this paper aims at assessing the potential of a laser source with a lower maximum power of 300W to enhance the flexibility of the process. Two types of samples – i.e. thin walls or bulk deposits − were produced at low laser power from alloy Ti-6Al-4V. Their geometry, microstructures and local hardness are characterised and correlated with the thermal history experienced during fabrication. [less ▲]

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See detailAutomatic derivation of multiharmonic formulations for nonlinear electromechanical problems with time dependent mesh deformation
Halbach, Alexandre ULg; Geuzaine, Christophe ULg

in 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE) (2016, May 05)

This paper describes a method to automatically derive multiharmonic finite element formulations for coupled, nonlinear electromechanical problems. It focuses on models of electrically actuated ... [more ▼]

This paper describes a method to automatically derive multiharmonic finite element formulations for coupled, nonlinear electromechanical problems. It focuses on models of electrically actuated micromembranes using both a staggered and a monolithic Newton iteration scheme. Two- and three-dimensional examples highlight the main properties of the proposed method. [less ▲]

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See detailGender, Jobs and Empowerment in Vietnamese Small Enterprises of Traditional Handicraft: Case Study in the Periphery of Hanoi
Nguyen, Thi Thu Hien ULg; Lebailly, Philippe

in The 2nd World Conference on Women’s Studies WCWS - 2016, 5th – 6th May, 2016 Colombo, Sri Lanka (2016, May 05)

Women are the main workforce of traditional craft sector in Vietnam. They not only actively participate in production, but also succeed in leading enterprises as managers. Even though women contribute ... [more ▼]

Women are the main workforce of traditional craft sector in Vietnam. They not only actively participate in production, but also succeed in leading enterprises as managers. Even though women contribute much to the achievement of companies, they face many constraints in working places due to theories of Confucianism and Buddhism. This research aims at answering two questions: (i) whether or not gender inequality exists in small scale craft enterprises and, (ii) how is empowerment the women employees in the firms. Both qualitative and quantitative methodologies are applied to collect information in order to clarify the research questions. Qualitatively, ethnographic approach is employed. It is explained that since 2014 the researchers go to the study areas to survey employment in the enterprises. In addition, participatory observation and oral history recording were also used to collect information (evidence) of gender inequality in employment and women empowerment in rural companies. Cross checking and supplementing were used for gathering information from communal leaders, women unions’ leaders and local residents. Quantitatively, descriptive statistics were used to analysis labor force, gender and employment of 50 enterprises in 3 traditional artisanal communes in Vietnam to find out gender inequality. Based on the result of analysis, some policy implications will be recommended to empower women as well as to reduce gender inequality in the small enterprises in rural areas [less ▲]

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

in Proceedings of the 5th Space Propulsion Conference, Roma, 2-5 mai 2016 (2016, May 02)

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See detailFucoidan: a marine polysaccharide for SPECT diagnosis of thrombosis
Chollet, Lucas; Saboural, Pierre; Rouzet, François et al

in Frontiers (2016, May)

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See detailIdentification des besoins des mères dans l’année suivant leur accouchement : une étude qualitative.
Slomian, Justine ULg; EMONTS, Patrick ULg; Vigneron, Lara et al

in 44èmes Assises Nationales des Sages-Femmes (2016, May)

Contexte de l’étude : La grossesse et l’accouchement sont deux étapes fondamentales dans la vie d’une femme. Plusieurs études ont montré que le malaise psychologique était relativement fréquent dans ... [more ▼]

Contexte de l’étude : La grossesse et l’accouchement sont deux étapes fondamentales dans la vie d’une femme. Plusieurs études ont montré que le malaise psychologique était relativement fréquent dans l’année suivant un accouchement. Objectifs : L’objectif de cette étude était de déterminé les besoins des mères dans l’année suivant leur accouchement (qu’elles aient vécu un épisode psychologique pathologique ou non). Méthode : Plusieurs étapes qualitatives ont été entreprises dans cette étude. Premièrement, nous avons conduit 22 entretiens individuels et un focus group réunissant des mères ayant vécu ou non un épisode de détresse psychologique. Nous avons ensuite mené deux autres focus : un avec des professionnels de la santé, l’autre avec des pères. Le but était de comparer les besoins maternels avec la perception des professionnels ainsi que des pères. Règles éthiques : Cette étude a reçu l’accord du comité d’éthique hospitalo-facultaire du CHU de Liège sous le numéro : 2015/48. Chaque participante a signé un formulaire de consentement éclairé quant à sa participation à l’étude ainsi qu’à l’autorisation de diffuser les résultats de façon confidentielle. Résultats : Les besoins des mères après leur accouchement ont été classés en 4 grandes catégories : le besoin d’information, le besoin de soutien psychologique, le besoin de partage d’expériences et le besoin de support matériel et pratique. Les femmes ne se sentent pas assez informées dans cette période de vie difficile. Elles ne se sentent pas non plus assez soutenues au point de vue psychologique mais également dans les tâches ménagères. Elles sont souvent fatiguées et se posent beaucoup de questions. Elles ont besoin de partager cette expérience de vie et elles ont besoin d’être rassurées et de se sentir comprises. Il semblerait qu’il y ait des différences de vécu d’expériences entre les mères et les professionnels mais également entre les mères et les pères. Conclusion : L’arrivée d’un bébé est une étape importante dans la vie d’une femme et d’un couple. Cela demande un remaniement tant sur les plans physique que psychologique et social. Les mères semblent ressentir un manque de support à différents niveaux au cours de la période postnatale. Cette étude procure des pistes pour répondre à leurs besoins et tenter de prévenir le risque de détresse psychologique dans la période postnatale. [less ▲]

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See detailDealing with crop rotation in agroforestry: the impact of shade on winter wheat and sugar beet growth and yield under belgium conditions
Artru, Sidonie ULg; Garré, Sarah ULg; Hiel, Marie-Pierre ULg et al

in Book of Abstract- 3rd European Agroforestry Conference 2016 (2016, May)

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See detailModelling and Emulation of an Unbalanced LV Feeder with Photovoltaic Inverters
López-Erauskin, Ramón; Gyselinck, Johan; Olivier, Frédéric ULg et al

in Proc. of 8th IEEE Benelux Young researchers symposium in Electrical Power Engineering (2016, May)

In this paper, the penetration of grid-connected pho- tovoltaic systems is studied, experimentally tested and compared to simulation results. In particular, how the inverse current flow and unbalance ... [more ▼]

In this paper, the penetration of grid-connected pho- tovoltaic systems is studied, experimentally tested and compared to simulation results. In particular, how the inverse current flow and unbalance situations affect the voltage in the low-voltage grid. Thus, a test platform has been developed for obtaining experimental results with grid-tied commercial inverters. Photo- voltaic arrays are emulated and subjected to different irradiance profiles and the inverters are controlled to produce at different power conditions. A model has been developed in order to repro- duce the same operating conditions and working environment. Simulations are performed with the software PowerFactory and the results compared to the experimental ones. [less ▲]

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