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See detailImage analysis of X-ray microtomograms of Pd-Ag/SiO2 xerogel catalysts supported on Al2O3 foams
Blacher, Silvia ULg; Léonard, Angélique ULg; Heinrichs, Benoît ULg et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2004), 241(1-mars Sp. Iss. SI), 201-206

In order to preshape and mechanically strengthen, Pd-Ag/SiO2 xerogel catalysts were carried out in Al2O3 foams (pore-sizes similar to40 mum). The final material consists of a Pd-Ag/SiO2 xerogel ... [more ▼]

In order to preshape and mechanically strengthen, Pd-Ag/SiO2 xerogel catalysts were carried out in Al2O3 foams (pore-sizes similar to40 mum). The final material consists of a Pd-Ag/SiO2 xerogel immobilized in the open cells of the alumina foam. The localization of the xerogel catalyst in alumina foams of various pore structure was studied by X-ray microtomography. The three-dimensional (3D) porous structure was reconstructed from the consecutive cross-sections obtained by this technique. Total porosity, porous density distribution, and pore-size distribution were determined by image analysis on the free and impregnated supports. Our results show that the success of the used impregnation technique depends on the pore structure of the support. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailImage analysis of X-ray microtomograms of soft materials during convective drying
Léonard, Angélique ULg; Blacher, Silvia ULg; Marchot, Pierre ULg et al

in Journal of Microscopy (2003), 212(Pt 2), 197-204

X-ray microtomography is used to explore the textural evolution that soft materials undergo during a drying treatment. An original image processing algorithm is applied to vertical projections and ... [more ▼]

X-ray microtomography is used to explore the textural evolution that soft materials undergo during a drying treatment. An original image processing algorithm is applied to vertical projections and reconstructed cross-section images in order to quantify the texture at different stages of drying. Measurements are performed both on grey-level and on binary images. It is shown that X-ray microtomography is a very promising tool in the field of drying investigations. It can be used to determine internal moisture profiles, and to follow crack development and shrinkage in an accurate and non-destructive way. This information is crucial to validate drying models. Waste-water sludges are used as test materials to assess the validity of the proposed methodology. The management of these sludges, often including a drying stage, will become a challenge in the forthcoming years in accordance with environmental regulations. Samples collected in two waste-water treatment plants are investigated. Their analysis by X-ray microtomography brings to the fore two different drying behaviours, illustrating that sludge drying is a complex unit operation very sensitive to the way the material is produced. [less ▲]

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See detailImage analysis of X-ray microtomograms of soft materials during convective drying: 3D measurements
Léonard, Angélique ULg; Blacher, Silvia ULg; Marchot, Pierre ULg et al

in Journal of Microscopy-Oxford (2005), 218(Pt 3), 247-252

Drying dewatered sludge leads to a complex three-dimensional porous structure. Moreover, this operation is dependent on the way the material is processed. In this study, textural changes of sludge ... [more ▼]

Drying dewatered sludge leads to a complex three-dimensional porous structure. Moreover, this operation is dependent on the way the material is processed. In this study, textural changes of sludge extrudates submitted to convective drying are followed by a 3D image analysis of reconstructed X-ray microtomograms. To achieve this goal, two different wastewater sludges collected in wastewater treatment plant after the thickening step and dewatered in the laboratory are used. It is showed that the evolution of the 3D-crack ratio vs. the residual water content evolves following a hyperbolic law. The 3D opening crack size distribution reveals two different types of pore development, i.e. a continuous pore size evolution for one sludge and the sudden appearance of cracks for the other sludge. [less ▲]

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See detailImage analysis of X-ray tomograms of sludge during convective drying in a pilot-scale fixed bed
Li, Jie ULg; Plougonven, Erwan ULg; Fraikin, Laurent ULg et al

in Chemical Engineering Science (2015), 134

Detailed reference viewed: 16 (2 ULg)
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See detailImage analysis quantification of the angiogenesis on an embryonic implantation site
Le Maire, Sophie; Blacher, Silvia ULg; Labied, Soraya ULg et al

Conference (2005)

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See detailImage analysis, impedance spectroscopy and mercury porosimetry characterisation of freeze-drying porous materials
Blacher, Silvia ULg; Maquet, Véronique; Pirard, René ULg et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2001), 187-188

Image analysis and impedance spectroscopy have been used as potential tools for the characterization of the texture of ultramacroporous PLA foams prepared by freeze-drying. It has been shown that these ... [more ▼]

Image analysis and impedance spectroscopy have been used as potential tools for the characterization of the texture of ultramacroporous PLA foams prepared by freeze-drying. It has been shown that these two techniques actually provide valuable information on the structure of this material. They are complementary to mercury porosimetry, which does not allow morphological details to be distinguished. Image analysis of SEM micrographs of transverse cross-sections at two different magnifications gave information on both the macroporosity (1 μm < width < 10 μm) and ultramacroporosity (width > 10 μm). Impedance spectroscopy was used to investigate the transport properties of the three-dimensional porous matrices by measurement of ionic conduction [less ▲]

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See detailIMAGE and FAST observations of substorm recovery phase aurora
Mende, Stephen B; Frey, Harald U; Carlson, Charles W et al

in Geophysical Research Letters (2002), 29

Images from the IMAGE Wide-band Imaging Camera (WIC) and Spectrographic Imager (SI) channel SI12, were compared to in situ data taken by FAST. The IMAGE data segment began during the expansive phase of a ... [more ▼]

Images from the IMAGE Wide-band Imaging Camera (WIC) and Spectrographic Imager (SI) channel SI12, were compared to in situ data taken by FAST. The IMAGE data segment began during the expansive phase of a substorm and a double oval configuration evolved, consisting of a set of discrete poleward auroral forms and a separate more diffuse oval. The FAST data showed that a narrow (~1.5° latitude) region of downward currents separated the two ovals. The SI-12 optical observations showed a single oval of precipitating protons located on the equatorward side within the diffuse aurora. In agreement with IMAGE, the highest intensity proton flux measured by FAST was concentrated on the equatorward region although low flux protons were present throughout the entire double oval. In the lower latitude diffuse oval occasional structured auroras were embedded. These structured auroras were mostly created by inverted V type electrons but there were narrow regions in which intense beams of accelerated electrons were seen whose energy/pitch angle distribution and accompanying electric field data were consistent with Alfven wave acceleration. The poleward oval consisted of an intense inverted V precipitation event poleward of which a weak region of Alfven wave accelerated electrons was located. From the images it appears that the Alfven wave accelerated electron event in the diffuse auroral regions and the poleward features were part of short lived or rapidly moving auroral forms. [less ▲]

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See detailImage appraisal tools for electrical resistivity tomography
Caterina, David ULg; Beaujean, Jean ULg; Robert, Tanguy ULg et al

in Proceedings of SAGEEP (2011), 24

Image appraisal is a problem frequently encountered in electrical resistivity tomography (ERT), and more generally in non-linear geophysical inversion. It may include several aspects such as the ... [more ▼]

Image appraisal is a problem frequently encountered in electrical resistivity tomography (ERT), and more generally in non-linear geophysical inversion. It may include several aspects such as the identification of the geometry of buried structures, the detection of numerical artefacts, the estimation of the depth of investigation or the exactitude of inverted parameters. Geophysicists can rely on several tools published in the literature to address these issues. However, few studies offer a quantitative comparison on the performance of these tools concerning the different mentioned aspects. Moreover, to our knowledge, there is no commonly accepted methodology to handle image appraisal. In this contribution, we compared quantitatively the ability of different image appraisal indicators to reach different objectives (geometry, artefacts, depth of investigation, parameter resolution). Among possible image appraisal tools, the model resolution matrix (MRM), the cumulative sensitivity matrix (CSM) and the depth of investigation index (DOI) are the most cited ones and were studied here. We compared them first on numerical models representing different geological situations. This numerical benchmark showed that indicators based on the MRM and CSM were the more appropriate to appraise ERT images in terms of the geometry of structures and the exactitude of inverted parameters, DOI providing mainly qualitative information. On this basis, we propose a methodology to appraise field ERT images focusing on the resolution and geometric aspects (others being implicitly studied). First, True Synthetic Models (TSM), representing simplified cases of field ERT images, are built using available information. Then, through forward modelling, synthetic ERT data are computed and inverted to provide the Inverted Synthetic Models (ISM). Afterwards, a comparison between TSM and ISM (or their gradients for geometry) is made in order to define the errors on inverted parameters. This discrepancy is then plotted with respect to resolution indicator values and points out in every tested cases a resolution range over which the errors abruptly increase allowing the definition of threshold values. The final step consists in applying the threshold values on the field ERT images and to validate the results with a posteriori knowledge. [less ▲]

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See detailImage Appraisal Tools for Electrical Resistivity Tomography
Caterina, David ULg; Beaujean, Jean ULg; Robert, Tanguy ULg et al

Poster (2010, January 12)

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See detailImage Context Discovery from Socially Curated Contents
Kimura, Akisato; Ishiguro, Katsuhiko; Marcos Alvarez, Alejandro ULg et al

in Proceedings of the 21st ACM International Conference on Multimedia (2013, October)

This paper proposes a novel method of discovering a set of image contents sharing a specific context (attributes or implicit meaning) with the help of image collections obtained from social curation ... [more ▼]

This paper proposes a novel method of discovering a set of image contents sharing a specific context (attributes or implicit meaning) with the help of image collections obtained from social curation platforms. Socially curated contents are promising to analyze various kinds of multimedia information, since they are manually filtered and organized based on specific individual preferences, interests or perspectives. Our proposed method fully exploits the process of social curation: (1) How image contents are manually grouped together by users, and (2) how image contents are distributed in the platform. Our method reveals the fact that image contents with a specific context are naturally grouped together and every image content includes really various contexts that cannot necessarily be verbalized by texts. [less ▲]

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See detailL'image dans le concours EUROPAN : étude de l'évolution de la représentation graphique du projet
Boutemadja, Abdelkader ULg; Reiter, Sigrid ULg

Conference (2015, June 02)

EUROPAN se distingue par sa volonté de mettre en avant de jeunes architectes mais aussi « d’approfondir les connaissances et les réflexions dans le domaine de l’habitat et de l’urbanisme ». Le fait que le ... [more ▼]

EUROPAN se distingue par sa volonté de mettre en avant de jeunes architectes mais aussi « d’approfondir les connaissances et les réflexions dans le domaine de l’habitat et de l’urbanisme ». Le fait que le projet lauréat a pour visée d’être traduit en une commande et une réalisation concrète permet d’attirer des projets réalistes dont la finalité est de s’inscrire dans un processus décisionnel complexe et complet. En outre, signalons que les auteurs de projets y présentent leur idées presqu’exclusivement au travers de la représentation graphique dont le support est le même pour tous (3 planches A1) et que ce concours a fait l’objet d’un archivage important. Ainsi, ce champ d’expérimentation nous permet d’analyser l’évolution durant les dernières décennies des modes de représentation graphique du projet dans le cadre du concours d’idées architecturales et urbaines. L’analyse des documents graphiques retenus dans ce champ d’expérimentation nous a permis de relever les différentes typologies graphiques utilisées dans leur composition. Il s’agit de : chorèmes, de schémas, de plans/coupes/élévations, d’images 3D et de textes. Ces différentes typologies se déclinent en sous-entités suivant les relations que les unes établissent avec les autres (par exemple : des schémas en 3D ou des images 3D intégrant des coupes …). Grâce à une analyse comparative du nombre de types utilisés et des surfaces dédiées à chacun d’eux au cours des différentes sessions, nous avons constaté un usage assez constant des chorèmes et des schémas mais une évolution de l’utilisation des images 3D par rapport aux plans/coupes/élévations donnant de plus en plus d’importance aux images 3D au détriment de documents graphiques plus conventionnels avec même parfois des transferts de charges symboliques d’un type à l’autre. Cette recherche montre ainsi que l’image 3D est désormais intégrée comme l’un des moyens les plus importants de communication et de partage d’informations concernant le projet urbain. Enfin, cette recherche révèle l’intérêt pour notre discipline de développer une méthode spécifique de lecture de la représentation graphique du projet architectural et urbain, de manière à étudier l’image non seulement comme support de représentation mais aussi en tant que système de communication. La méthode de lecture des images proposée est fondée sur l’utilisation et l’adaptation de méthodes et techniques d’interprétations de projets et d’images développées initialement dans les domaines de la systémique et de la sémiotique ; elle pourra être utilisée dans des recherches ultérieures pour continuer d’améliorer notre compréhension de l’évolution des représentations graphiques du projet. [less ▲]

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See detailL’image dans le discours scientifique : statuts et dispositifs de visualisation
Dondero, Maria Giulia ULg; Miraglia, Valentina

in Visible (2010), 5

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See detailL’image dans le texte ou le texte dans l’image ? : Le cas de l’Égypte ancienne
Winand, Jean ULg

in Visible (2006), 2(2), 141-158

Detailed reference viewed: 88 (3 ULg)
See detailL'image de l'ouvrier dans l'historiographie belge de 1830 à 1914
Geerkens, Eric ULg

Master's dissertation (1987)

Detailed reference viewed: 67 (13 ULg)
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See detailL’image de la femme africaine dans les Passions. Réalités sociales et élaboration d’un modèle chrétien
Hamdoune, Christine; Fialon, Sabine ULg

Scientific conference (2008, June 27)

Detailed reference viewed: 8 (1 ULg)
See detailL'image de la France en Belgique francophone (1944-1951), état d'avancement des recherches
Lanneau, Catherine ULg

Scientific conference (2003, March 19)

Detailed reference viewed: 35 (0 ULg)
See detailImage deconvolution of lensed QSOs observed with the NOT: Competing with the HST
Burud, I.; Courbin, F.; Magain, Pierre ULg

in Karttunen, H.; Piirola, V. (Eds.) Astrophysics with the NOT, Proceedings of the conference held in Turku (1999)

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See detailImage Deconvolution of the Radio Ring PKS 1830-211
Courbin, F.; Lidman, C.; Frye, B. L. et al

in Astrophysical Journal (1998), 499

New high-quality Keck and ESO images of PKS 1830-211 are presented. By applying a powerful new deconvolution algorithm to these optical and infrared data, both images of the flat spectrum core of the ... [more ▼]

New high-quality Keck and ESO images of PKS 1830-211 are presented. By applying a powerful new deconvolution algorithm to these optical and infrared data, both images of the flat spectrum core of the radio source have been identified. An extended source is also detected in the optical images which is consistent with the expected location of the lensing galaxy. The source counterparts are very red at I-K~7 , which suggests strong Galactic absorption with additional absorption by the lensing galaxy at z=0.885 and is consistent with the detection of high-redshift molecules in the lens. [less ▲]

Detailed reference viewed: 5 (2 ULg)