References of "Pirard, Eric"
     in
Bookmark and Share    
Full Text
See detailHistoire d'un ElDorado - Cinq siècles d'exploration du sous-sol sud-américain
Pirard, Eric ULg

Scientific conference (2012, April 17)

Une présentation du rapport de l'Amérique Latine au richesses de son sous-sol, depuis la découverte de l'Amérique jusqu'à aujourd'hui.

Detailed reference viewed: 50 (11 ULg)
Full Text
See detailRessources dans le rouge pour les technologies vertes ?
Pirard, Eric ULg

Conference given outside the academic context (2012)

Detailed reference viewed: 44 (10 ULg)
Full Text
See detailBall milling control: the reconciliation of macroscopic SensoMag® data with microscopic optical information.
Leroy, Sophie ULg; Köttgen, Axel ULg; de Haas, Bernard et al

Poster (2012, February 08)

Detailed reference viewed: 65 (10 ULg)
Full Text
Peer Reviewed
See detail3D Imaging of individual particles : a review
Pirard, Eric ULg

in Image Analysis and Stereology (2012), 31(2), 65-77

In recent years, impressive progress has been made in digital imaging and in particular in three dimensional visualisation and analysis of objects. This paper reviews the most recent literature on three ... [more ▼]

In recent years, impressive progress has been made in digital imaging and in particular in three dimensional visualisation and analysis of objects. This paper reviews the most recent literature on three dimensional imaging with a special attention to particulate systems analysis. After an introduction recalling some important concepts in spatial sampling and digital imaging, the paper reviews a series of techniques with a clear distinction between the surfometric and volumetric principles. The literature review is as broad as possible covering materials science as well as biology while keeping an eye on emerging technologies in optics and physics. The paper should be of interest to any scientist trying to picture particles in 3D with the best possible resolution for accurate size and shape estimation. Though techniques are adequate for nanoscopic and microscopic particles, no special size limit has been considered while compiling the review. [less ▲]

Detailed reference viewed: 38 (1 ULg)
Full Text
See detailEffet de l'empilement et de la forme des additions dans les propriétés des liants à matrice cimentaire
He, Huan; Courard, Luc ULg; Michel, Frédéric et al

in Georgin, Jean-François (Ed.) Compte-rendu des Journées Scientifiques du (RF)2B (2012)

Cement blending with mineral admixtures, especially with by-product or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was ... [more ▼]

Cement blending with mineral admixtures, especially with by-product or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was proposed to replace of “coarse” cement grains by the inert fillers for sustainable cement in the low w/c concrete cement. As a basic mechanism, particle packing plays an important role in such replacement or blending. In the first part of study, the paper discusses the particle packing aspect of cement grains, limestone filler (LF) and LF blended cement. The new developed wet packing method and a dry packing method are proposed for the evaluation purpose. Particle size distributions (PSDs) and particle shape of different powders are firstly characterized by an advanced image analysis system. The paper presents results of packing tests with the influences of PSD, particle shape, cement type, vibration, mixing, superplasticizer (SP), blending proportions, etc. The advantages and limitations of two packing methods are also discussed in this paper. [less ▲]

Detailed reference viewed: 28 (2 ULg)
Full Text
Peer Reviewed
See detailShape simulation of granular particles in concrete and applications in DEM
Huan, He; Stroeven, Piet; Pirard, Eric ULg et al

in Brandt, A.M.; Olek, J.; Glinicki, L.A. (Eds.) et al Proceedings of the International Symposium Brittle Matrix Composites 10 (2012)

Detailed reference viewed: 30 (1 ULg)
Full Text
See detailEffet de l’empilement et de la forme des additions sur les propriétés des liants à matrice cimentaire
He, Huan; Courard, Luc ULg; Michel, Frédéric ULg et al

in Georgin, Jean-François (Ed.) Recueil des communications des journées scientifiques du (RF)²B (2012)

Mélanger le ciment avec des additions minérales, en particulier avec des sous-produits industriels, permet de réduire efficacement la consommation de ciment et de réduire son impact environnemental ... [more ▼]

Mélanger le ciment avec des additions minérales, en particulier avec des sous-produits industriels, permet de réduire efficacement la consommation de ciment et de réduire son impact environnemental. Récemment, un concept novateur a été proposé en vue de remplacer les plus gros grains de ciment par les charges inertes, en vue du développement d’un ciment durable. En tant que mécanisme de base, l’empilement des particules joue un rôle important dans le remplacement ou le mélange. Dans la première partie de l'étude, l’empilement des grains de ciment, de filler calcaire (LF) et de ciment mélangé est abordé. Une nouvelle méthode, basée sur l’empilement en phase humide, est comparée à une méthode d'empilement à sec. La distribution de taille des particules (PSD) et la forme des particules des différentes poudres sont caractérisées sur base d’un système d'analyse d'image avancée. Le document présente les résultats des tests d’empilement avec l’influence du paramètre PSD, de la forme des particules, du type de ciment, de l’énergie de vibration, du mélange et du superplastifiant (Sp). Les avantages et les limites des deux méthodes sont également discutés. [less ▲]

Detailed reference viewed: 37 (5 ULg)
Full Text
Peer Reviewed
See detailParticle packing density and limestone fillers for more sustainable cement
He, Huan ULg; Courard, Luc ULg; Pirard, Eric ULg

in Key Engineering Materials [=KEM] (2012), 517

Cement blending with mineral admixtures, especially with byproduct or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was ... [more ▼]

Cement blending with mineral admixtures, especially with byproduct or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was proposed to replace of “coarse” cement grains by the inert fillers for sustainable cement in the low w/c concrete cement. As a basic mechanism, particle packing plays an important role in such replacement or blending. In the first part of study, the paper discusses the particle packing aspect of cement grains, limestone filler (LF) and LF blended cement. The new developed wet packing method and a dry packing method are proposed for the evaluation purpose. The paper presents results of packing tests with the influences of PSD, cement type, vibration, mixing, blending proportions, etc. The advantages and limitations of two packing methods are also discussed in this paper. [less ▲]

Detailed reference viewed: 125 (18 ULg)
Full Text
See detailRessources dans le rouge pour les technologies vertes ?
Pirard, Eric ULg

Scientific conference (2011, November 16)

De nombreuses technologies qualifiées de vertes s’imposent dans notre quotidien et d’autres s’annoncent dans un futur très proche. Véhicules électriques, éoliennes, panneaux photovoltaïques, écrans plats ... [more ▼]

De nombreuses technologies qualifiées de vertes s’imposent dans notre quotidien et d’autres s’annoncent dans un futur très proche. Véhicules électriques, éoliennes, panneaux photovoltaïques, écrans plats, éclairages LED, … Ces technologies sont peu énergivores au premier abord, mais elles sont très gourmandes en éléments rares comme le Gallium, le Néodyme, le Lithium, le Germanium, etc. L’Union Européenne, par son appel « Raw Materials Initiative », a pris conscience de son extrême dépendance vis-à-vis de pays tiers en matière d’approvisionnement en métaux stratégiques. Ces mêmes pays, parmi lesquels la Chine ou la Bolivie, cherchent quant à eux à limiter leurs exportations de matières premières brutes, espérant devenir demain des fournisseurs de composants électroniques à haute valeur ajoutée (cathodes au Li, aimants permanents, diodes, …). Dans ce contexte, on peut s’interroger sur le devenir et la pérennité de la technologie européenne. Cet exposé aura pour objectif de clarifier les enjeux et les flux de ressources au travers de quelques exemples choisis. [less ▲]

Detailed reference viewed: 110 (22 ULg)
Full Text
Peer Reviewed
See detailCharacterization of fine aggregates in concrete by different experimental approaches
He, Huan ULg; Courard, Luc ULg; Pirard, Eric ULg et al

in Proceedings 13 Int. Congress for Stereology (2011, October)

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties ... [more ▼]

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties of concrete. On another hand, physical characteristics of aggregate are primarily assumed to be relevant to granular behavior of aggregate. Therefore, characterization of aggregate is of high relevance to concrete studies. In this study, different types of fine aggregate used in concrete, namely river sand and crushed limestone, are selected for morphological characterization. Traditional sieve analysis and laser diffraction method are employed for separation and size analysis of specimens. Different types of fine aggregate samples with comparable size ranges are then analyzed by two advanced dry (static) and wet (dynamic) image analysers. These new analysers are especially suitable for characterization of fine particles, which is difficult by traditional image analysis equipments. Size and shape characteristics of different fine aggregates will be revealed by different experimental methods. The results on different parameters for shape characterization will be compared and discussed. [less ▲]

Detailed reference viewed: 82 (16 ULg)
Full Text
See detailCharacterization of fine aggregates in concrete by different experimental approaches
He, Huan; Courard, Luc ULg; Pirard, Eric ULg et al

in Proceedings 13 Int. Congress for Stereology (2011, October)

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties ... [more ▼]

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties of concrete. On another hand, physical characteristics of aggregate are primarily assumed to be relevant to granular behavior of aggregate. Therefore, characterization of aggregate is of high relevance to concrete studies. In this study, different types of fine aggregate used in concrete, namely river sand and crushed limestone, are selected for morphological characterization. Traditional sieve analysis and laser diffraction method are employed for separation and size analysis of specimens. Different types of fine aggregate samples with comparable size ranges are then analyzed by two advanced dry (static) and wet (dynamic) image analysers. These new analysers are especially suitable for characterization of fine particles, which is difficult by traditional image analysis equipments. Size and shape characteristics of different fine aggregates will be revealed by different experimental methods. The results on different parameters for shape characterization will be compared and discussed [less ▲]

Detailed reference viewed: 53 (1 ULg)
Full Text
See detailTextural Descriptors for Multiphasic Ore Particles
Perez-Barnuevo, Laura; Pirard, Eric ULg

in Proceedings 13 Int. Congress for Stereology (2011, October)

The monitoring of mineral processing circuit based on particle liberation analysis using quantitative image analysis has become a routine technique within the last decades. But liberation indices are ... [more ▼]

The monitoring of mineral processing circuit based on particle liberation analysis using quantitative image analysis has become a routine technique within the last decades. But liberation indices are computed as weight proportions, which is not convenient when complex texture ores are treated by flotation. In these cases, liberation has to be computed as phase surface available to reactants, and the type of intergrowth between phases has to be characterized so as to determine the possibility of liberation. To achieve this characterization some indices have been developed in terms of 2D phase contact and mineral surfaces exposed. These indices, as well as indices suggested by other authors and additional measures, have been explored on simple synthetic textures ranging from single to multiple inclusions and single to multiple veins. The ability of these parameters to discriminate the various textures is analyzed [less ▲]

Detailed reference viewed: 81 (9 ULg)
Full Text
See detailSensitivity of particle size and shape parameters with respect to digitization
Pirard, Eric ULg; Dislaire, Godefroid

in Proceedings 13 Int. Congress for Stereology (2011, October)

The growing success of image analysis based instruments for particle characterization demonstrates the importance of size and shape analysis in operations involving particulate materials. ISO norms for ... [more ▼]

The growing success of image analysis based instruments for particle characterization demonstrates the importance of size and shape analysis in operations involving particulate materials. ISO norms for particle sizing using image analysis are being elaborated to clarify nomenclature and measurement principles. But despite this, there is still a lack of understanding of how the digital representation of a particle affects different size and shape parameters. It is the purpose of this paper to explore the magnitude of estimation errors of a series of size and shape parameters from different digital image representations of a single particle. These images are simulated from grey level images of black particles presenting a Gaussian transition towards their white background. Particles themselves are generated from analytical functions sampled by digital grids with variable densities, positions and orientations. Results of inscribed disk, elongation, circularity, roughness, roundness, etc. are plotted as a function of grid density (magnification) with error bars corresponding to the scattering of results for variable thresholds, grid translations and rotations As a conclusion, confidence intervals are given for parameters as a function of magnification and the most sensitive and robust methods of shape analysis are put forward. [less ▲]

Detailed reference viewed: 76 (5 ULg)
Full Text
Peer Reviewed
See detailOptical analysis of particle size and chromite liberation from pulp samples of a UG2 ore regrinding circuit
Leroy, Sophie ULg; Dislaire, Godefroid; Bastin, David ULg et al

in Minerals Engineering (2011), 24

Since the early seventies high chromite and low base metal sulphide (BMS) contents of the UG2 reef imposes technological challenges to mineral processors and extractive metallurgists. Forty years later ... [more ▼]

Since the early seventies high chromite and low base metal sulphide (BMS) contents of the UG2 reef imposes technological challenges to mineral processors and extractive metallurgists. Forty years later, particle size distribution and size by size mineralogy are considered as key factors to the continuous improvement of the UG-2 ore metallurgy. With the successful development of ultra fine grinding technologies, a compromise has to be found between fine grinding to achieve platinum group minerals liberation and to avoid the overgrinding of gangue minerals, especially chromite gangue which is detrimental in smelting process. Indeed, fine chromite grains, despite of being naturally hydrophobic mineral, can be recovered in flotation concentrate by entrainment. In addition, overgrinding also increase liberation of naturally floatable gangue (talc) which contaminate the concentrate and need to be controlled during flotation. In this paper, innovative techniques of single particle image analysis from both dry and wet samples have been tentatively used to assess the chromite particle size distribution and the chromite grade of samples taken from a secondary milling circuit. Preliminary results demonstrate excellent potential for online particle imaging making use of both the particle geometry (size, shape) and the optical properties (translucency). [less ▲]

Detailed reference viewed: 162 (31 ULg)
Full Text
See detailLes ressources du sous-sol bolivien : mirage ou véritable El Dorado ?
Pirard, Eric ULg

in Gresea Echos (2011), 67

Made In Bolivia : Le sud se développe en solo... Le cas du Lithium

Detailed reference viewed: 65 (4 ULg)
Full Text
See detailAn Experimental Approach to Link Powder Physical Properties to 3D Particle Shape
Califice, Arnaud ULg; Lumay, Geoffroy ULg; Vandewalle, Nicolas ULg et al

in Particulate Systems Analysis 2011 (2011, September)

A series of samples have been characterized by 3D image analysis (using X-Ray microtomography). The samples consist of blends of metallic particles: steel shot abrasives (“balls”), steel fibres and ... [more ▼]

A series of samples have been characterized by 3D image analysis (using X-Ray microtomography). The samples consist of blends of metallic particles: steel shot abrasives (“balls”), steel fibres and angular steel grit particles. The blends were systematically prepared in different proportions of the raw products. Various shape and size parameters were measured on the particles: equivalent volume diameter (dV), maximum inscribed sphere diameter (dIN), particle length (maximum Feret diameter), particle elongation (El), particle flatness (Fl) etc. The results are expressed as statistical shape and size parameters, expressed both as volume and number weighted distributions. The blends have been tested for compaction using a cylindrical container which experiences a series of 500 free falls over a height of 3mm. The compaction dynamics was monitored using a sensor that measures the evolution of the solid volume fraction as a function of the tap number. From the obtained compaction curve, the Hausner ratio and a flowability index were extracted. The same blends have also been analysed using a rotating drum at different rotation speeds to analyze the evolution of the flowing angle. As the system is based on the analysis of a time sequence of 50 images (separated by 0.5 sec) it is possible to measure the intermittent character of the powder flow. The resulting measure is a cohesive index of the powder. The results obtained from physical testing were systematically plotted as a function of various statistical indices of the shape and size distributions in order to reveal correlations between particle shape properties and physical behaviour. Some clear trends appeared, demonstrating the influence of particle shape on powder physical properties. [less ▲]

Detailed reference viewed: 55 (10 ULg)
Full Text
Peer Reviewed
See detailTechnological Characterisation of West African Iron Ores in Order to Predict their Performance in the Beneficiation Process
Dubron, Liesbet ULg; Pirard, Eric ULg; Pirson, Arnaud

in Proceedings Iron Ore 2011 (2011, July)

This study details a mineralogical and textural characterisation of West African iron ores with an emphasis on their behavior during mineral processing. By means of both qualitative and quantitative ... [more ▼]

This study details a mineralogical and textural characterisation of West African iron ores with an emphasis on their behavior during mineral processing. By means of both qualitative and quantitative characterisation, a simulation of the beneficiation process applied to these iron ores is performed. A series of different analytical tools are used, including: X-Ray Diffraction (XRD) for qualitative mineralogical analysis; qualitative optical microscopy (phase identification, description of micro-textures) and (semi)quantitative optical microscopy (counting of particles, phases and textural types); and chemical analyses. All the information provided by these analytical methods are combined into a quantitative mineralogical and textural analysis, here called “modal analysis”, which enables us to simulate the capability of West African iron ores to be beneficiated by magnetic and gravimetric separation techniques. [less ▲]

Detailed reference viewed: 89 (8 ULg)
Full Text
Peer Reviewed
See detailReal-Time Image Analysis of Iron Ore Cores and Drill Chips to Complement Spectral Measures
Belligoï, Thomas; Ramanaidou, Eric; Pirard, Eric ULg

in Proceedings of Iron Ore 2011 (2011, July)

Diamond cores and drill chips provide the only direct physical evidence for ore containing rocks. Early characterisation of cores and drill chips is important as it provides critical information for ... [more ▼]

Diamond cores and drill chips provide the only direct physical evidence for ore containing rocks. Early characterisation of cores and drill chips is important as it provides critical information for downstream processing. Traditional characterisation techniques include visual logging by a geologist or analytic and spectroscopic methods but they are time consuming and can miss some important textural or geomechanical features. The goal of this work is to evaluate the application of image analysis to iron ore cores and drill chips and to suggest improvements to existing core-scanning and chip monitoring systems. Two samples of massive ore differing by their mineralogy and texture, as well as two different batches of drill chips, have been imaged and analysed. Results are compared in function of the imaging system and the classifi cation algorithms. As a conclusion, despite the necessity for more testing and improvements in calibration and lighting, it is obvious that image analysis technologies can bring a lot of useful information in the perspective of a geometallurgical mapping of the deposit. [less ▲]

Detailed reference viewed: 114 (12 ULg)