References of "Pirard, Eric"
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See detailUsing Artificial Vision for the Microscopic Identification of Ores with Reflected Light: Preliminary Results.
Castroviejo, Ricardo; Brea, Carolina; Perez-Barnuevo, Laura et al

in Proceedings 10th Biennial SGA Meeting (2009)

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See detailENVIRONMENTAL ASPECTS OF CLAY EXPLOITATION FOR FIRED CLAY BRICKS IN CAMEROON
Njoya, A.; Bastin, D.; Melo, U. et al

Poster (2009)

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See detailPrediction of acid mine generating potential: Validation using mineralogy
Bouzahzah, Hassan; Benzaazoua, Mostafa; Plante, Benoît et al

in Proceedings 24th International Applied Geochemistry Symposium (2009)

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See detailCaracterización y cuantificación autmatizadas de menas metálicas mediante visión artificial : proyecto cameva
Castroviejo, Ricardo; Catalina, Juan-Carlos; Bernhardt, Heinz-Juergen et al

in Actos del XIII Congreso Latino Americano de Geologia (2008)

The CAMEVA project (Automated system for the identification and quantitative measurement of ore minerals) aims to develop an automated system able to perform the identification and quantification of the ... [more ▼]

The CAMEVA project (Automated system for the identification and quantitative measurement of ore minerals) aims to develop an automated system able to perform the identification and quantification of the different minerals present in a sample of metallic ores, in order to facilitate their industrial use. The system comprises a motorised reflected light microscope, a filter wheel (monochromator), a research BW camera, and a computer running a digital image analysis software associated to an expert system specially developed for this application. Multispectral reflectance values are measured for visible light and near IR and UV (350-1000 nm), and no polarisation is usually employed in order to reduce measurement variability due to mineral anisotropy. Mineral identification is carried out by comparison of measured reflectances with spectral reflectance databases (e.g. IMA-COM). Previous experiences showed that the most common ores can be differentiated through the analysis of a microscopic RGB colour image, by constraining the search with additional information such as the type of deposit and the corresponding mineral association. The project goes further, and intends to identify most of the ores from multi-spectral images, including non-visible bands, resorting to an expert system specifically built to deal with the different types of information available (spectral reflectance, sample origin, mineral associations, morphology, etc). 2 Validation of the method will be carried out by comparative análisis of standards and samples exchanged between the laboratories. Development pays special attention to the total automation of the process (including calibration) and to the self-learning capabilities of the system. Contacts with research institutions and with the industry will allow to apply the system to real problems. The system can be used to control the processing of ores as well as to prevent pollution for the protection of the environment (e.g. sulphides in coal or in industrial tailings). Further applications can be envisaged in the future: e.g. other minerals, coal or materials, particles, etc. [less ▲]

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See detailLandslide Detection Methods, Inventory Analysis and Susceptibility Mapping Applied to the Tien Shan, Kyrgyz Republic.
Danneels, Gaëlle; Havenith, Hans-Balder ULg; Strom, A. et al

in Proc. of the First World Landslide Forum (2008)

This paper presents results of the last five years of landslide detection and landslide susceptibility mapping in the Central and Southern Tien Shan. Landslide inventories have been compiled for areas of ... [more ▼]

This paper presents results of the last five years of landslide detection and landslide susceptibility mapping in the Central and Southern Tien Shan. Landslide inventories have been compiled for areas of major interest in the Kyrgyz Republic. For those areas, landslides were first mapped manually using KFA satellite images and aerial photographs. Recently, a landslide detection method has been developed in order to map landslides automatically. This method is based on a neural network scheme applied to detect particular slope failure features from remote sensing data. Multi-spectral and/or panchromatic ASTER and SPOT images as well as digital elevation models (DEMs) are used as inputs. This automatic method is designed to map medium-size mass movements (105-107 m3). This approach supplements the manual mapping of large slope failures and helps to complete the inventory of mass movements and related landslide susceptibility/hazard maps for large areas within the Tien Shan. Size-frequency analyses have been applied to the two existing regional landslide inventories. These size-frequency analyses revealed the incompleteness of the respective inventories (in the low-size domain) as well as regional and local differences due to natural and anthropogenic influences. To be able to perform reliable susceptibility and size-frequency analyses, the completed inventories need to be verified. At present, we perform local verification by manual mapping and control, but automatic verification methods are being developed. They will also allow us to determine the level of uncertainties. Ongoing research is focused on the propagation of uncertainties throughout the chain of processing. [less ▲]

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See detailFrom spectrophotometry to multispectral imaging of ore minerals in visible and near infrared (VNIR) microscopy.
Pirard, Eric ULg; Bernhardt, Heinz-Juergen; Catalina, Juan-Carlos et al

in GU; BUTCHER (Eds.) Proceedings of ICAM 2008 (2008)

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See detailSpreading segregation of blended fertilizers : influence of particles properties
Miserque, Olivier; Pirard, Eric ULg; Schenkel, Yves et al

in Applied Engineering in Agriculture (2008), 24(2), 137-144

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See detailMapping evaporitic minerals in Sud Lipez salt lakes (Bolivia) using remote sensing
Caceres, Fernando; Ali-Ammar, Hamid; Pirard, Eric ULg

in Reviews in Economic Geology (2008), 16

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See detailModal analysis of mineral blends using optical image analysis versus X ray diffraction
Bouzahzah, Hassan; Califice, Arnaud ULg; Benzaazoua, Mostafa et al

in GU, Ying; BUTCHER, Alan; STEELE, David (Eds.) Proceedings of International Congress for Applied Mineralogy ICAM08 (2008)

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See detailTechniques and applications for predictive metallurgy and ore
Lane, Geoff; Martin, Chris; Pirard, Eric ULg

in Minerals Engineering (2008), 21

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See detailLandslide detection from remote sensing images using statistical and ANN classification methods
Danneels, Gaëlle; Havenith, Hans-Balder ULg; Pirard, Eric ULg

in Geophysical Research Abstracts (2007)

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See detailParticle texture analysis using polarized light imaging and grey level intercepts
Pirard, Eric ULg; Lebichot, Sophie; Krier, William

in International Journal of Mineral Processing (2007), 84(1-4), 299-309

The usual characterization of particulate ore material with image analysis includes modal analysis and liberation analysis. Both methods include stereological corrections based on intercept length ... [more ▼]

The usual characterization of particulate ore material with image analysis includes modal analysis and liberation analysis. Both methods include stereological corrections based on intercept length distributions within each phase of interest. The first principle of stereology relies on a simple assumption of uniform random sectioning, whereas the liberation models require all particles to have similar textural properties. However, for the sake of adequate prediction of ore behavior in industrial processes it is becoming more and more important to be able to describe particle populations in terms of texture classes. Among the texture analysis techniques, this paper focuses on mean intercept length (MIL). It brings two important improvements: the first one is to improve grain boundary imaging by using images of bireflectant minerals under plane polarized illumination, the second one is to consider intercept analysis on grey level images instead of binary ones. The method is illustrated on a selection of critical hematite textures found within banded iron formations. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailImpact of microbial activities on the mineralogy and performance of column-scale permeable reactive iron barriers operated under two different redox conditions
Van Nooten, Thomas; Lieben, François; Dries, Jan et al

in Environmental Science & Technology (2007), 41(16), 5724-5730

The present study focuses on the impact of microbial activities on the performance of various long-term operated laboratory-scale permeable reactive barriers. The barriers contained both aquifer and Fe-0 ... [more ▼]

The present study focuses on the impact of microbial activities on the performance of various long-term operated laboratory-scale permeable reactive barriers. The barriers contained both aquifer and Fe-0 compartments and had received either sulfate or iron(Ill)-EDTAto promote sulfatereducing and iron(Ill)-reducing bacteria, respectively. After dismantlement of the compartments after almost 3 years of operation, DNA-based PCR-DGGE analysis revealed the presence of methanogenic, sulfate-reducing, metalreducing, and denitrifying bacteria within as well as up- and downgradient of the Fe-0 matrix. Under all imposed conditions, the main secondary phases were vivianite, siderite, ferrous hydroxy carbonate, and carbonate green rust as found by scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD). Under sulfate-reduction promoting conditions, iron sulfides were formed in addition, resulting in 7 and 10 times higher degradation rates for PCE and TICE, respectively, compared to unreacted iron. These results indicate that the presence of sulfate-reducing bacteria in or around iron barriers and the subsequent formation of iron sulfides might increase the barrier reactivity. [less ▲]

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See detailSIZE DISTRIBUTION OF METALLIC POWDERS : A COMPARISON OF DIGITAL IMAGING AND LASER DIFFRACTION
Gregoire, Max; Michel, Frédéric ULg; Campana, Florent et al

Poster (2007)

Automated image analysis of particles under controlled orientation (SIA) is becoming a challenging technique for laser diffraction (LD) in the field of sizing metallic particles above 5 μm. Thanks to ... [more ▼]

Automated image analysis of particles under controlled orientation (SIA) is becoming a challenging technique for laser diffraction (LD) in the field of sizing metallic particles above 5 μm. Thanks to optimal particle dispersion and fully automated microscopic imaging, it is now possible to gather individual measurements on thousands of particles within a minute. The aim of this paper is to compare results obtained with both image analysis and laser diffraction from a selection of powders (figure 1) in the range between 5 μm and 250 μm. [less ▲]

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See detailCaractérisation granulo-morphologique en 3D de poudres métalliques par micro-tomographie rayons-x
Gregoire, Max; Pirard, Eric ULg

in Dodds, J. A. (Ed.) Science & Technologie des Poudres - PMF 2007 (2007)

La morphologie des particules est une propriété essentielle pour comprendre et prédire leur rhéologie, leur agglomération, leur compaction et bien d'autres de leurs propriétés physiques. Suite à l ... [more ▼]

La morphologie des particules est une propriété essentielle pour comprendre et prédire leur rhéologie, leur agglomération, leur compaction et bien d'autres de leurs propriétés physiques. Suite à l'apparition de nouvelles techniques d'imagerie en trois dimensions adaptées aux matériaux, il est à présent possible d'étendre les descripteurs de forme existant en deux dimensions à la troisième. Deux échantillons de particules métalliques dont l'étendue granulaire est de 150-250 μm ont été selectionnés. Le choix de ces poudres est un véritable défi car la forme complexe des particules justifie l'élaboration de nouveaux descripteurs de taille et de forme. Cet article présentes les résultats de la caractérisation morphologique en trois dimensions de matériaux granulaires. L'acquisition d'images est pratiquée par microtomographie des rayons X permettant une résolution inférieure à 10 μm. Pour chaque particule, le volume, la surface, l'allongement, l'aplatissement, la convexité et le rayon de la sphère maximale inscrite sont calculés en trois dimensions. Les algorithmes écrits pour mesurer ces propriétés ont été validés sur des particules synthétiques. La réalisation d'une analyse morphologique complète de quelques milliers de particules permet d'appréhender les paramètres de forme de façon statistique. Finalement, les résultats seront confrontés à ceux obtenus par analyse d'image statique (SIA) en 2D. [less ▲]

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See detailAccuracy of size distributions obtained from single particle static digital image analysis.
Gregoire, Max; Dislaire, Godefroid; Pirard, Eric ULg

in Proceedings PARTEC2007 (2007)

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See detailAnalysis of landslide susceptibility in the Suusamyr region, Tien Shan: statistical and geotechnical approach
Havenith, Hans-Balder ULg; Strom, Alexander; Caceres, Fernando et al

in Landslides (2006), 3(1), 39-50

The Suusamyr region is located in the northern part of the Tien Shan Range in Central Asia. In 1992, this region was hit by the Ms = 7.3 Suusamyr earthquake triggering several large landslides along the ... [more ▼]

The Suusamyr region is located in the northern part of the Tien Shan Range in Central Asia. In 1992, this region was hit by the Ms = 7.3 Suusamyr earthquake triggering several large landslides along the Suusamyr Valley and on the southern slopes of the adjacent Suusamyr Range. One of these landslides had been investigated by geophysical and geotechnical methods in order to determine local trigger factors. The present paper focuses on the influence of geological and morphological factors upon landslide occurrence on a regional scale. The analysis is based on a digital data set including landslides triggered in 1992 and several older landslides as well as various types of digital elevation models (DEMs), ASTER image data, and geological and active fault maps. These data were combined to compute landslide susceptibility (LS) maps using statistical methods, Landslide Factor and Conditional Analyses (LFA, CA), as well as a geotechnical one, the Newmark's Method (NM). The landslide data set was also analyzed with respect to the size-frequency relationship. [less ▲]

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