X-Ray Microtomography Studies of Tannin-Derived Organic and Carbon Foams

in Microscopy and Microanalysis (2009), 15

Water desorption from resorcinol-formaldehyde hydrogels and adsorption in the resulting xerogels

in Microporous & Mesoporous Materials (2009), 117

Water desorption isotherms of resorcinol-formaldehyde (RF) hydrogels and subsequent water adsorption isotherms of the resulting xerogels are determined using the static gravimetric method, at various ... [more ▼]

Water desorption isotherms of resorcinol-formaldehyde (RF) hydrogels and subsequent water adsorption isotherms of the resulting xerogels are determined using the static gravimetric method, at various temperatures. Isotherms obtained from samples synthesized at various pH are compared. Two different mechanisms are involved in RF hydrogels water desorption. At large relative humidity the capillary tension resulting from water removal induces a macroscopic shrinkage of the gel, whereas at low humidity water is evaporated with no network deformation. These two mechanisms are analyzed using a plastic deformation model and the Guggenheim-Anderson-de Boer (GAB) model, respectively. Adsorption isotherms of RF xerogels are analyzed using the GAB model. [less ▲]

Simulations of Structures in Packed Columns and Validation by X-ray Tomography

in Industrial & Engineering Chemistry Research (2009), 48(1), 202-213

Packing simulations of generic, nonspherical pellets were performed and compared with experimental data sets obtained using X-ray Computerized tomography (CT). Two modified versions of what was previously ... [more ▼]

Packing simulations of generic, nonspherical pellets were performed and compared with experimental data sets obtained using X-ray Computerized tomography (CT). Two modified versions of what was previously a purely geometrical, digitally based packing algorithm were implemented. Both are aimed at incorporating the effects of particle interaction forces, one utilizing the distinct element method (DigiDEM) and the other an intermediate solution (collision-guided packing or DigiCGP). This article summarizes the models and the simulations performed using these two modified versions of DigiPac and, for model validation purposes, compares the predicted results with the corresponding X-ray tomographic scans of packed columns, in terms of bulk density, local packing density profiles, and pellet orientation distributions. For packed beds of relatively large and identical pellets, the simulation results indicate that particle-particle and particle-wall interactions cannot be ignored if realistic packing structures are to be obtained by simulation and even a simplistic treatment of these interactions can produce significantly more realistic packing structure than none at all. [less ▲]

Convective drying of gels: comparison between simulated and experimental moisture profiles obtained by X-ray microtomography

in Thorat, B. N. (Ed.) Drying 2008 - Proceedings of the 16th International Drying Symposium (IDS2008), Vol. C. (2008, November)

Convective drying tests of silt: experimental studies and modelling

Conference (2008, October 06)

Production of adsorbent materials from dried residual sludges

Poster (2008, September)

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

in Journal of Porous Materials (2008), 15(4), 397-403

Poly(ε-caprolactone) foams were prepared, via a batch process, by using supercritical CO2 as foaming agent. Their porous structure was characterized through mercury porosimetry, helium and mercury ... [more ▼]

Poly(ε-caprolactone) foams were prepared, via a batch process, by using supercritical CO2 as foaming agent. Their porous structure was characterized through mercury porosimetry, helium and mercury pycnometry, scanning electron microscopy (SEM) and X-ray microtomography observations coupled with image analysis. The pore size distributions obtained by these two latter techniques show that the pore structure is more homogeneous when the foaming process is performed under a high CO2 saturation pressure (higher than 250 bars). [less ▲]

3D characterization of the porous structure of activated carbon packed beds using X-ray microtomography

Poster (2008, June)

Effect of far-infrared radiation assisted drying on microstructure of banana slices: An illustrative use of X-ray microtomography in microstructural evaluation of a food product

in Journal of Food Engineering (2008), 85(1), 154-162

X-ray microtomography coupled with image analysis represents a non-destructive technique, which allows scanning an entire sample to obtain such information as total pore volume and pore size distribution ... [more ▼]

X-ray microtomography coupled with image analysis represents a non-destructive technique, which allows scanning an entire sample to obtain such information as total pore volume and pore size distribution without the need of serial cuts as in the case of scanning electron microscopy (SEM). The technique has been applied successfully to obtain reliable microstructural information of many products undergoing different physical and chemical processes. However, the technique has still found limited use in food processing. To illustrate the use of X-ray microtomography the technique was applied to investigate the effect of far-infrared radiation (FIR) assisted drying on microstructure of a food product viz. banana. Two representative drying techniques, i.e., low-pressure superheated steam drying (LPSSD) and vacuum drying (VACUUM) were tested. Banana slices were dried by LPSSD-FIR at two different temperatures (80 and 90 degrees C) at a fixed pressure of 7 kPa. The total pore volume and pore size distribution of dried banana slices were then determined using X-ray microtomography. The results were also compared with those of products dried by LPSSD without FIR. Far-infrared radiation was found to modify the structure of the dried bananas by increasing their final porosity. The same effect of FIR was also observed in the case of vacuum drying with FIR (VACUUM-FIR). An increase of the drying temperature was also found to globally lead to an increase in the final porosity of the products. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

Use of X-ray tomography for drying-related applications

in Tsotsas, Evangelos; Mujumdar, Arun S. (Eds.) Modern Drying Technology, Vol 2. Experimental Techniques (2008)