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Congratulations to for successfully defending his PhD thesis on the "Development of A Novel Ultra-High Vacuum Diffusion Apparatus for Investigating Knudsen Diffusion in Complex Pore Channels"!

The objective of this experimental setup is to investigate geometrical effects on Knudsen diffusion in nanopores by "scaling up" to macroscopic scales, namely working under high vacuum to achieve the Knudsen regime (mean free path much larger than the channel diameter). This has been extraordinarily challenging to put into practice, requiring Haiyue to combine technical engineering acumen with a fundamental understanding of vacuum science, physical chemistry, and materials under vacuum, and translating that in practice whilst understanding the chemical engineering context. Haiyue used 3D printing to generate fractal pore shapes based on computational design.

Thanks also to Sander Baltussen who has worked on this area at TU Delft (The Netherlands) with Marc-Olivier Coppens, and shared helpful experience with Haiyue. At Ïã¸ÛÁùºÏ²ÊÖÐÌØÍø Chemical Engineering and the Centre for Nature Inspired Engineering (CNIE), we could return to this topic thanks to technical progress, but it remains very challenging even today to ensure proper control over the vacuum and materials properties.

Constraints imposed by the Covid-19 pandemic have made it necessary to cut short some experiments, however Haiyue made sure to convincingly test the premise of the instrument and the approach, and to combine his experiments with computations for validation, comparing with previous theoretical work by Dr Kourosh Malek and Marc-Olivier Coppens. Knudsen diffusion in channels is a century-old topic, and yet the significant effects of short pore lengths and surface roughness in porous materials used for catalysis and separations are almost always ignored even today. More on this is discussed in a recent review.

Many thanks to his PhD examiners, (University of Manchester) and Dr Federico Galvanin (Ïã¸ÛÁùºÏ²ÊÖÐÌØÍø) for a thorough examination of Haiyue's work.

continues work on this topic at the Centre for Nature Inspired Engineering (CNIE).