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See detailEtude d'incidences de la centrale S.P.E. de Seraing
Marchal, Jean ULg; Gulan, C.; Centre Environnement de l'Ulg

Book published by Editions "Centre Environnement Ulg" - éditeur responsable J. Smitz (1991)

Detailed reference viewed: 46 (4 ULg)
See detailEtude d'un cas d'aphasie progressive primaire
Adam, Stéphane ULg

Scientific conference (2007, November 27)

Detailed reference viewed: 35 (1 ULg)
See detailEtude d'un cas de démence sémantique précoce
Adam, Stéphane ULg; Reznik, Régine

Scientific conference (2009, January 20)

Detailed reference viewed: 50 (1 ULg)
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See detailEtude d'un cas particulier très important du mouvement de rotation d'un corps solide
Folie, François ULg

in Bulletin de la Classe des Sciences. Académie Royale de Belgique (1899), 3

The author searches if the Eulerian nutation is insignificant and if the hour remains uniform when we take for reference point the instantaneous pole by restricting to the case of solid earth and where ... [more ▼]

The author searches if the Eulerian nutation is insignificant and if the hour remains uniform when we take for reference point the instantaneous pole by restricting to the case of solid earth and where there are no disruptive forces. [less ▲]

Detailed reference viewed: 10 (0 ULg)
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See detailEtude d'un cas typique de myopathie postanesthésique équine
D'Ieteren, G.; Spyropoulos, E.; Philippart, C. et al

in Annales de Médecine Vétérinaire (1983)

Detailed reference viewed: 20 (1 ULg)
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See detailEtude d’un concentrateur solaire basé sur une combinaison optique diffractive/réfractive pour applications spatiales
Michel, Céline ULg

Doctoral thesis (2015)

Continued demand for new applications from spacecrafts leads to larger power needs. For most of them, the primary energy sources are solar panels. However, these solar panels are heavy and expensive ... [more ▼]

Continued demand for new applications from spacecrafts leads to larger power needs. For most of them, the primary energy sources are solar panels. However, these solar panels are heavy and expensive, mainly due to solar cells and their coverglass. The power need increase requires thus new concepts of solar panels. Furthermore, space environment is highly constraining: the vacuum limits heat trans- fer since convection is not allowed, there is contamination modifying the light spectrum reaching cells, ultraviolet light induces a yellowing of silicone glue, radiations degrade pho- tovoltaic cells, etc. Usually, multi-junctions (MJ) cells are used, that are strongly sensitive to spectral modification in their incident spectrum due to their series connected structure (the worst cell defines the whole output performance). The power dimensioning of solar panels is then based on end of life (EOL) PV cells expected performance. Reducing the sensitivity to increase EOL output power is then another challenge for space applications. This thesis aims to answer to both problems, by the proposition and study of a new lightweight solar concentrator with spectral splitting. This conceptual concentrator is composed of a Fresnel lens for sunlight concentration, coupled to a surface relief diffraction grating to spectrally split incident light, forming a single optical element in silicone. The concentration behavior allows a reduction of solar cells area (including its coverglass), replaced by a lightweight silicone lens, reducing the global cost and mass. The lateral spectral separation will permit other types of cells than the usual MJ cells. To demonstrate the concept, two single junctions (SJ) solar cells are placed side by side, the first collecting visible light, the second collecting near IR light. Since cells are electrically independent, sensitivity is lower and EOL output power can surpass standard MJ cells systems. Moreover, cells combination is nearly free: all photovoltaic technology can be used and combined, opening the solar concentration field to other technologies than MJ. This work studies and evaluates the pros and cons of diffraction grating/Fresnel lens combinations as solar concentrator with spectral splitting. The analysis includes the choice of material, optical developments and optimizations (grating selection, freeform lenses, grating period optimization along the lens, etc.), electrical modeling and methods to find the best cells combination as well as the modeling of expected output power, a thermal simulation, weight and deployment considerations, and approaches of sensitivity with spectral modifications. Some experimental results complete the study. Two main configurations were developed: a first with a blazed grating, and a second with a symmetrical lamellar grating. Both configurations, after optimization, show similar performances: a global geometrical concentration ratio around 5-6× (ratio between lens width and the total width of the two cells), a tracking error tolerance up to 0.7◦, no drastic degradation with respect to deformations, fabrication errors, etc., an output power at begin of life (BOL) better than a classical concentrator focusing on a SJ cell or a planar solar panel composed of SJ cells. Both configurations present also a BOL specific mass [kg/W] lower than a classical planar solar panel covered by MJ cells, and a lower sensitivity to space environment, with theoretical larger EOL output power depending on chosen PV cells combinations. Existing deployment systems are proposed and discussed. Also, an experimental prototype of the optical element was realized, with optical results close to simulations. Some adaptations to terrestrial concentrators, other spectra, or using more than 2 different SJ cells are also introduced, highlighting the versatility of our concept. Results demonstrate thus the coherence of the concept, leading to experimentally feasible and quite tolerant concentrator, with interesting cost reduction thanks to concentration and specific weight reduction. However, optical losses due to the non-perfect spectral splitting of the grating is too high to be able to surpass MJ cells systems BOL up to now, and the lower sensitivity of our concentrator cannot completely compensate this lack of performance at EOL. To reach better performances than MJ systems, from cost, mass, radiation resistance, etc. point of view and to exploit the obvious gain in sensitivity, the concentrator needs thus further investigations mainly related to cells combinations. Especially as our concept opens a lot of opportunities thanks to the complete independence of cells: other technologies are allowed, specific coatings can improve performances, ... Applications for Earth or places with different/changing incident spectra is another plausible perspective. Our concentrator with spectral splitting can also be a major advantage for specific scientific space missions like deep space missions. [less ▲]

Detailed reference viewed: 100 (26 ULg)
See detailEtude d'un critère complémentaire pour l'évaluation de la surchauffe des bâtiments dans le cadre de l'étude du confort en régime été (deuxième partie)
Dupont, Géraldine ULg; Hauglustaine, Jean-Marie ULg; Nourricier, S. et al

Report (2008)

The Walloon region entrusted to FPMs and ULg, the following study: - Study bibliography (research of work carried out in the field and the effective methods or recommendations in the adjoining countries ... [more ▼]

The Walloon region entrusted to FPMs and ULg, the following study: - Study bibliography (research of work carried out in the field and the effective methods or recommendations in the adjoining countries); - Application or development of the identified methods of calculating; - Comparison between the methods evaluation simplified and the results provided by a detailed software; - Proposal for a criterion or recommendations compared to the methods evaluated at the preceding points (advantages and disadvantages of the approaches taking into account the particular climate of Belgium). This criterion will be required by exploiting the currently available methods of evaluation of overheating. [less ▲]

Detailed reference viewed: 76 (15 ULg)
See detailEtude d’un échantillon de scories pour Excell Materials Europe
Bastin, David ULg; Krier, William

Report (2005)

Detailed reference viewed: 4 (0 ULg)
See detailEtude d'un écosystème fluvial perturbé : influence de la pollution d'origine industrielle et domestique sur les premiers niveaux de la chaine trophique
Descy, Jean-Pierre; Servais, Pierre; Thomé, Jean-Pierre ULg et al

Report (1992)

Le but du programme de recherches était de décrire le fonctionnement d'un milieu fluvial soumis à des pollutions diverses, principalement d'origine industrielle et domestique. Il visait entre autres à ... [more ▼]

Le but du programme de recherches était de décrire le fonctionnement d'un milieu fluvial soumis à des pollutions diverses, principalement d'origine industrielle et domestique. Il visait entre autres à complèter les connaissances fondamentales acquises au cours de recherches antérieures sur la Meuse. [less ▲]

Detailed reference viewed: 40 (1 ULg)
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See detailEtude d'un modèle mathématique empirique pour la mesure du transit gastro-intestinal
Debouche, Charles ULg

in Bulletin des Recherches Agronomiques de Gembloux (1974), 9(3), 335-342

Dans le cadre de l'étude de transit gastro-intestinal chez les polygastriques, cet article présente un modèle mathématique empirique pour décrire l'évolution de la concentration fécale en traceur ... [more ▼]

Dans le cadre de l'étude de transit gastro-intestinal chez les polygastriques, cet article présente un modèle mathématique empirique pour décrire l'évolution de la concentration fécale en traceur radioactif qui suit un marquage instantané. Ce modèle permet notamment de calculer le temps mis en moyenne par une particule pour traverser le tube digestif. [less ▲]

Detailed reference viewed: 61 (4 ULg)
See detailEtude d’un photobioréacteur à biomasse fixée pour la production de métabolites à haute valeur ajoutée
de Lamotte, Anne ULg

Master's dissertation (2013)

This master thesis is part of the FOTOBIOMAT research project financed by the Walloon Region, the aim of which is the development of a photobioreactor (PBR) using hybrid materials in the shape of beads ... [more ▼]

This master thesis is part of the FOTOBIOMAT research project financed by the Walloon Region, the aim of which is the development of a photobioreactor (PBR) using hybrid materials in the shape of beads within which photosynthetic microalgae producing high added-value metabolites are encapsulated. The most important limiting factor for the design of a PBR is the illumination of the culture medium. Externally illuminated rectangular reactors with a small thickness and with a high surface to volume ration allows optimising the supply of light. Nevertheless, due to the strong absorption by the cells, the recirculation of encapsulated microalgae is necessary to insure their access to the light provided at the PBR walls. To avoid any risk of deleterious shock or attrition, the beads recirculation is performed by fluidisation (hydraulic mixing) in a reclining reactor. The present work aims at describing the influence of the illumination distribution and of the fluid and particle flows on the levels and on the fluctuation of light intensity encountered by microalgae encapsulated in solid beads. Several experimental techniques were used to quantitatively characterise the illumination distribution and the liquid phase hydrodynamics. The motion of the solid particles was analysed more qualitatively. All these information on light distribution, liquid phase hydrodynamics and displacement of encapsulated microalgae in beads will have to be integrated and coupled to kinetic data on photosynthesis reactions to build a complete model of the PBR performance. [less ▲]

Detailed reference viewed: 136 (18 ULg)
See detailEtude d’un projet de centre commercial à Braine-l’Alleud
Germeau, V.; Risack, S.; Halleux, Jean-Marie ULg et al

Report (2000)

Detailed reference viewed: 89 (2 ULg)
See detailEtude d'un quai flottant de 36.000 t.- Etude préliminaire de variantes en acier et en béton
Marchal, Jean ULg; Rodriguez, S.; Gulan, C.

Report (1983)

Detailed reference viewed: 37 (0 ULg)
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See detailEtude d'un réseau cyclable à Liège
Hanocq, Philippe ULg; Piron, Frédéric; Occhiutto, Rita

in Croughs, Roger; Jacobs, Chantal; Guillaume, Michèle (Eds.) Communes cyclistes ? Ca existe ! ... Quelsques pistes pour promouvoir l'usage du vélo dans votre commune (1999)

Detailed reference viewed: 40 (7 ULg)
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See detailÉtude d’un séchoir solaire fonctionnant en mode direct et indirect
Chalal, Nadia; belhamri, Azeddine; Bennamoun, Lyes ULg

in Revue des Energies Renouvelables (2008)

Detailed reference viewed: 58 (5 ULg)