References of "Califice, Arnaud"
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See detailInfluence of particle shape on size distribution measurements by 3D and 2D image analyses and laser diffraction
Califice, Arnaud ULg; Michel, Frédéric ULg; Dislaire, Godefroid ULg et al

in Powder Technology (2013), 237

This paper highlights the fact that particle size distribution (PSD) is not unique for the same product, and is dependent on the chosen measurement technique, especially for asymmetric shapes. Laser ... [more ▼]

This paper highlights the fact that particle size distribution (PSD) is not unique for the same product, and is dependent on the chosen measurement technique, especially for asymmetric shapes. Laser diffraction and 2D image analysis are commonly used PSD measurement techniques. However, the resultsmay not be representative of the true physical dimensions of the particles. The influence of particle shape on PSD results obtained from 2D/3D image analysis and laser diffraction was investigated. Two metallic powders presenting extreme shape properties (round and elongated particles) were analyzed, as well as a blend of the two pure products. 2D image analysis and laser diffraction results were compared to 3D image analysis (measuring the true particle size). This paper compares the PSD results obtained from the three methods. Some commonly used size parameters in image analysis software did not give meaningful results in regard of the true physical dimensions of the particles. The existence of the two populations (products with extremely different shape and size characteristics) could not be identified with such size parameters, and laser diffraction also performed poorly. The PSD obtained from more precise size parameters (image analysis) better corresponded to the true dimensions of the particles. This study highlights the strengths and weaknesses of particle size analysis techniques when studying products presenting diverse particle shapes, and points out that caution is required in the choice of the size parameters, and in the interpretation of PSD results. [less ▲]

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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 ▲]

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See detailInfluence of particle flatness and elongation on size distributions obtained from laser diffraction, static and dynamic image analysis.
Califice, Arnaud ULg; Michel, Frédéric ULg; Dislaire, Godefroid et al

in World Congress on Particle Technology (2010, April)

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See detail3D and 2D particle image analysis of rock chips generated by core scratch tests.
Pirard, Eric ULg; Limam, Sami; Califice, Arnaud ULg et al

in World Congress on Particle Technology (2010, April)

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See detailQuantitative Microtexture Analysis of Carbonate Rocks Using Bireflectance Imaging
Jaimes Contreras, Rafael Antonio ULg; Pilawski, Dimitri; Califice, Arnaud ULg et al

in Proceedings IAMG 2010 (2010)

Microtextural analysis of rocks has been addressed by several authors as an essential means to better understand the natural genesis of the material. But, it is also of paramount importance to those who ... [more ▼]

Microtextural analysis of rocks has been addressed by several authors as an essential means to better understand the natural genesis of the material. But, it is also of paramount importance to those who try to predict the geotechnical or industrial behaviour of a rock under many forms of solicitation (mechanical, thermal, etc.). Quantitative modal (phase) analysis using point counting has already been discussed in depth by authors such as Chayes more than fifty years ago. Nowadays, automated image analysis with millions of pixels is easily available and improves statistical accuracy provided the classification step is correctly performed. Spitefully the assignment of a pixel to a given mineral phase or to a given crystal is often poorly satisfactory and remains the bottleneck of a fully automated textural analysis. Methods using a manual rotation of a polarizer in transmitted light microscopy have been developed by Starkey and Samantaray (1993) and further automated and improved by Fueten (1997). These allow to better delineate individual crystals in a thin section due to contrast in birefringence. In this paper a similar technique using multiple orientations of a polarizer in reflected light microscopy has been used to contrast individual crystals in carbonated rocks. The maximum and minimum grey levels registered for each pixel allow for computing a bireflectance image whose variance is a good indicator of the misalignment of cristallographical orientations in the section. Moreover, the maximum of the reflectance gradient obtained for each orientation generates a good image of the grain boundaries and the presence of pores. This last one is quantitatively analysed using the intercept method to estimate the mean and variance of the grain size distribution. The paper presents a quantitative comparison of several different microtextures. [less ▲]

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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)

Detailed reference viewed: 151 (22 ULg)