X-Ray Microtomography

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Angélique Léonard - One of the best experts on this subject based on the ideXlab platform.

  • Coupling X-Ray Microtomography and macroscopic soil measurements: a method to enhance near-saturation functions?
    Hydrology and Earth System Sciences, 2014
    Co-Authors: Eléonore Beckers, Erwan Plougonven, Angélique Léonard, Nicolas Gigot, Christian Roisin, Yves Brostaux, Aurore Degré
    Abstract:

    Agricultural management practices influence soil structure, but the characterization of these modifications and consequences are still not completely understood. In this study, we combine X-Ray Microtomography with retention and hydraulic conductivity measurements in the context of tillage simplification. First, this association is used to validate Microtomography information with a quick scan method. Secondly, X-Ray Microtomography is used to increase our knowledge of soil structural differences. Notably, we show a good match for retention and conductivity functions between macroscopic measurements and microtomographic information. Microtomography refines the shape of the retention function, highlighting the presence of a secondary pore system in our soils. Analysis of structural parameters for these pores appears to be of interest and offers additional clues for soil structure differentiation, through – among others – connectivity and tortuosity parameters. These elements make Microtomography a highly competitive instrument for routine soil characterization.

  • x ray Microtomography a porosity based thresholding method to improve soil pore network characterization
    Geoderma, 2014
    Co-Authors: Eléonore Beckers, Erwan Plougonven, Angélique Léonard, Christian Roisin, Simona M Hapca, Aurore Degré
    Abstract:

    Abstract X-Ray Microtomography, through quantification of soil structure at the microscale, could greatly facilitate the current understanding of soil hydrodynamic behaviour. However, binarisation method and processing choices are subjective and can have a strong impact on results and conclusions. In this study, we test a new method based on the porosity detectable by X-Ray Microtomography, while validation is achieved through comparison of soil microtomogram information with soil physical measurements. These measurements consist of water retention and unsaturated hydraulic conductivity using two different soil populations with only structural differences. To assess the porosity-based method performances, we compare it to four other methods, namely the global method of Otsu and three recent soil-dedicated local methods. The robustness of the porosity-based method is also tested in regard to different pre-processing procedures. In this paper we demonstrate that soil segmentation through a porosity-based method is an interesting issue. Indeed, it is less demanding in terms of time and computational requirements than its alternatives, and combines robustness and performances broadly comparable with the recent local methods.

  • Use of X-Ray Microtomography to study the homogeneity of carbon nanotube aqueous suspensions and carbon nanotube/polymer composites
    Carbon, 2012
    Co-Authors: Majid Haghgoo, Erwan Plougonven, Ali Akbar Yousefi, Jean-paul Pirard, Angélique Léonard
    Abstract:

    Abstract X-Ray Microtomography was used to study the stability and homogeneity of concentrated carbon nanotube (CNT) aqueous suspensions and CNT/resorcinol–formaldehyde gel composites. Various CNT distribution states were achieved by modifying the CNT concentration, sonication time and resting time. X-Ray Microtomography is able to discriminate between zones with different CNT concentration levels and can be used as a non-destructive and fast tool to characterize the homogeneity of suspensions and composite systems at the micron scale.

  • Comparison of agricultural soils' structure depending on tillage system using X-Ray Microtomography
    2010
    Co-Authors: Eléonore Beckers, Angélique Léonard, Sarann Ly, Aurore Degré
    Abstract:

    This study aims at characterizing agricultural soils’ structure depending on the tillage system: conventional tillage or conservational tillage. Tillage reduction is an increasing practice, but the micro-structural effects on soils and on their hydrodynamic parameters are still not well described. Recent research shows non-converging results. Our point is to highlight fundamental differences in structure through characterization of soils porosity’s parameters using X-Ray Microtomography measurements coupled to image analysis. This attempt is in line with a more integrated experiment of which the aim is to quantify the effects of tillage intensity on lateral flow production, and finally on global water balance. Parameters’ measurements consist in a combined approach, based on two different space-time scales of exploration: fundamental scale, with soil sampling campaign for Microtomography analysis, and field scale, with continuous flow measurements (plots’ dimensions: 18*28 m). For their part, parameters for water balance determination (precipitation, evapotranspiration. . . ) are monitored on the field. All of these measurements have the main objective of hydrological modeling enhancement by taking into account a better lateral flow description. Discussion in this paper will focus on the first results obtained by X-Ray Microtomography measurements.

  • Non-destructive characterization of deer (Cervus Elaphus) antlers by X-Ray Microtomography coupled with image analysis
    Journal of Microscopy, 2007
    Co-Authors: Angélique Léonard, Jean-paul Pirard, L. P. Guiot, Michel Crine, Marc Balligand, Silvia Blacher
    Abstract:

    Summary X-Ray Microtomography coupled with image analysis was tested as a non-destructive alternative method for the textural characterization of the trabecular part of deer antlers (Cervus Elaphus). As gas adsorption and mercury intrusion cannot be applied on this soft and spongy material, its pore texture was, up to now, determined from histological sections that give only two-dimensional information. In this work, X-Ray Microtomography is used to scan entire or half pieces of antlers and three-dimensional image analysis is performed in order to assess the differences between samples collected at various antler locations. Results clearly show a porosity profile along the sample diameter. The pore size distribution is showed to be dependent on the sample original site.

Anke R. Kaysser-pyzalla - One of the best experts on this subject based on the ideXlab platform.

  • Damage fluctuations in creep deformed copper studied with synchrotron X-Ray Microtomography
    International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde), 2020
    Co-Authors: Ramin Abbasi, Loïc Renversade, Krzysztof Dzieciol, András Borbély, Anke R. Kaysser-pyzalla
    Abstract:

    International audienceDamage localization during power law creep of copper has been investigated in situ with synchrotron X-Ray Microtomography. The analysis of the area fraction of cavities corresponding to a given material slice has revealed that damage localization begins relatively early at half of the creep lifetime. The amplitude of the maximum fluctuation shows parabolic behavior as a function of mean void volume fraction. Existing models of damage evolution underpredict the amount of real damage and overpredict power-law creep life-time

  • Damage fluctuations in creep deformed copper studied with synchrotron X-Ray Microtomography
    International Journal of Materials Research, 2012
    Co-Authors: Ramin Abbasi, Loïc Renversade, Krzysztof Dzieciol, András Borbély, Anke R. Kaysser-pyzalla
    Abstract:

    Damage localization during power law creep of copper has been investigated in situ with synchrotron X-Ray Microtomography. The analysis of the area fraction of cavities corresponding to a given material slice has revealed that damage localization begins relatively early at half of the creep lifetime. The amplitude of the maximum fluctuation shows parabolic behavior as a function of mean void volume fraction. Existing models of damage evolution underpredict the amount of real damage and overpredict power-law creep life-time.

Olivier Rozenbaum - One of the best experts on this subject based on the ideXlab platform.

  • 3-D characterization of weathered building limestones by high resolution synchrotron X-Ray Microtomography
    Science of the Total Environment, 2011
    Co-Authors: Olivier Rozenbaum
    Abstract:

    Understanding the weathering processes of building stones and more generally of their transfer properties requires detailed knowledge of the porosity characteristics. This study aims at analyzing three-dimensional images obtained by X-Ray Microtomography of building stones. In order to validate these new results a weathered limestone previously characterised (Rozenbaum et al., 2007) by two-dimensional image analysis was selected. The 3-D images were analysed by a set of mathematical tools that enable the description of the pore and solid phase distribution. Results show that 3-D image analysis is a powerful technique to characterise the morphological, structural and topological differences due to weathering. The paper also discusses criteria for mathematically determining whether a stone is weathered or not. © 2011 Elsevier B.V.

Fredrik Forsberg - One of the best experts on this subject based on the ideXlab platform.

Daniel Bideau - One of the best experts on this subject based on the ideXlab platform.

  • Analysis by X-Ray Microtomography of a granular packing undergoing compaction.
    Physical review. E Statistical nonlinear and soft matter physics, 2003
    Co-Authors: Patrick Richard, Pierre Philippe, Fabrice Barbe, Stéphane Bourlès, Xavier Thibault, Daniel Bideau
    Abstract:

    Several acquisitions of X-Ray Microtomography have been performed on a beads packing while it compacts under vertical vibrations. An image analysis allows to study the evolution of the packing structure during its progressive densification. In particular, the volume distribution of the pores reveals a large tail, compatible to an exponential law, which slowly reduces as the system gets more compact. This is quite consistent, for large pores, with the free volume theory. These results are also in very good agreement with those obtained by a previous numerical model of granular compaction.

  • Analysis by X-Ray Microtomography of a granular packing undergoing compaction
    Physical Review E, 2003
    Co-Authors: Patrick Richard, Pierre Philippe, Fabrice Barbe, Stéphane Bourlès, Xavier Thibault, Daniel Bideau
    Abstract:

    ESRF, BP 220, F-38043 Grenoble Cedex, France(Dated: today)Several acquisitions of X-Ray Microtomography have been performed on a beads packing while itcompacts under vertical vibrations. An image analysis allows to study the evolution of the packingstructure during its progressive densification. In particular, the volume distribution of the poresreveals a large tail, compatible to an exponential law, which slowly reduces as the system gets morecompact. This is quite consistent, for large pores, with the free volume theory. These results are alsoin very good agreement with those obtained by a previous numerical model of granular compaction.

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