The use of tomography to determine the kinetics of water vapour adsorption

in Proceedings of Carbon 2005 – The International Carbon Conference (2005, July)

Production of resorcinol formaldehyde xerogels by convective drying

in Proceedings of the joint conference of AFSIA (Association Française pour le Séchage dans l’Industrie et l’Agriculture) and Working group on Drying of EFCE at INA P-G, Paris, 12th and 13th May, 2005 (2005, May)

The porous structure of biodegradable scaffolds obtained with supercritical CO2 as foaming agent

Poster (2005, May)

Convective drying of wastewater sludges: Influence of air temperature, superficial velocity, and humidity on the kinetics

in Drying Technology (2005), 23(8), 1667-1679

The influence of air temperature, velocity, and humidity during convective drying of two different sludges (A and B) is investigated through a 3 3 factorial design. For sludge A, a constant drying flux ... [more ▼]

The influence of air temperature, velocity, and humidity during convective drying of two different sludges (A and B) is investigated through a 3 3 factorial design. For sludge A, a constant drying flux period is observed, while sludge B is characterized by a long decreasing drying flux phase. A sensitivity analysis shows that temperature is the main operating parameter affecting the drying kinetics. Mass and heat transfer coefficients as well as water evaporation capacities are calculated from drying curves. Transfer coefficients are related to operating conditions through dimensionless relations. For both sludges, a linear relation is found between water evaporation capacity and the maximal measured drying flux. [less ▲]

Image reconstruction in X-ray tomography

Scientific conference (2004, August)

Computed X-ray tomography investigations in packed beds

Scientific conference (2004, August)

Image analysis of X-ray microtomograms of Pd-Ag/SiO2 xerogel catalysts supported on Al2O3 foams

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 ▲]

Apports de la microtomographie à rayons X pour l'étude du séchage convectif de matériaux déformables : suivi du retrait, de la fissuration et des profils d'humidité interne

Scientific conference (2004, March)

Measurement of shrinkage and cracks associated to convective drying of soft materials by X-ray microtomography

in Drying Technology (2004), 22(7), 1695-1708

Traditionally, the measurement of shrinkage occurring during drying is performed by destructive or poorly accurate techniques such as volume displacement methods. Cracks detection and quantification are ... [more ▼]

Traditionally, the measurement of shrinkage occurring during drying is performed by destructive or poorly accurate techniques such as volume displacement methods. Cracks detection and quantification are realised either by destructive techniques or sophisticated but expensive nondestructive ones (NMR imaging). X-ray microtomography in combination with image analysis provides an accurate, nondestructive and easy to use technique to determine simultaneously shrinkage and crack extent. Results reported in this article concern drying of wastewater sludges whose management will become a real challenge in the years to come. These results show a clear relation between drying kinetics and crack development. This could be related to the development of internal diffusional limitations inducing moisture gradients and mechanical stresses leading to cracks formation. [less ▲]

Image analysis of X-ray microtomograms of soft materials during convective drying

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 ▲]