Publications by authors named "J Dewanckele"

We use dynamic micro-computed tomography (micro-CT) with a high temporal resolution to visualize water penetration through the porous network of immediate-release pharmaceutical solid tablets and characterize dynamic swelling and disintegration mechanisms. We process the micro-CT images using two theoretical scenarios that reflect different paths of pore structure evolution: a scenario where tablet porosity remains constant during the swelling process and a scenario where the tablet porosity progressively diminishes and eventually closes during the swelling process. We calculate the time evolution of the volume of water absorbed by the tablet and, specifically, absorbed by the excipients and the pore structure, as well as the formation and evolution of cracks.

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The thermal stability of gypsum-based materials, and in this context, especially their long-term behavior, is the background of our current research activities. A comprehensive investigation program was compiled in which detailed examinations of various model materials exposed to thermal loads were carried out. The understanding of the partly not entirely consistent state of knowledge shall be sharpened especially by in situ observations of the thermally induced conversion reaction of gypsum into hemihydrate.

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In the past few years, dynamic computed tomography (CT) approaches or uninterrupted acquisitions of deforming materials have rapidly emerged as an essential technique to understand material evolution, facilitating in situ investigations ranging from mechanical deformation to fluid flow in porous materials and beyond. Developments at synchrotron facilities have led this effort, pointing to the future of the technique. In the laboratory, recent developments at TESCAN XRE have made it possible to image, reconstruct and inspect dynamic processes in the laboratory with a temporal resolution below 10 s, meaning that an entire acquisition from 0 to 360° is completed within 10 s.

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Article Synopsis
  • This study investigates how the microstructure and existing flaws in Lede and Noyant limestones affect their weathering behavior through acid tests and freeze-thaw cycles.
  • High-resolution X-ray CT, SEM-EDS, and thin section microscopy were used to observe and analyze the non-destructive 3D structural changes during weathering, revealing distinct patterns in each limestone type.
  • The results showed that while both limestones experienced similar weathering causes, their patterns differed significantly due to their unique microstructures, impacting how gypsum crystallizes and affects the stone.
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Article Synopsis
  • Researchers studied weathering processes in natural building stones using techniques like thin-section petrography, SEM, XRD, and XRF, but emphasized the need for non-destructive methods to gather quantitative data on structural changes.
  • The study focused on the Lede stone, a historical calcareous sandstone, and analyzed its response to gaseous SO(2) using high-resolution X-ray tomography before, during, and after exposure to visualize gypsum crust formation and its effects on pore modification in 3D.
  • Results indicated increased porosity beneath the gypsum layer and showed signs of micro-cracks and dissolution on quartz grain boundaries, providing valuable insights into gypsum weathering mechanisms and porosity changes in natural stones.
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