In this study, a numerical simulation model was developed in conjunction with X-ray CT (computed tomography) images of actual facemasks in order to clarify the behavior of submicron-sized particles in the facemask microstructure. It was found that the presence of large pores inside the microstructure caused streamlines to curve near the facemask domain, and particles accompanying the streamlines were more likely to be collected on the pore surface. Although the presence of pores results in a decrease in a pressure drop and the collection efficiency, the above effect suppresses the decrease in the collection efficiency and thus improves the performance (quality factor) of the facemask.

The mechanical reliability of products must be assured for scaling up and production of complex-shaped components by spark plasma sintering (SPS) of spray-dried granules. The evolution of morphologies of pores and defects, which control the mechanical strength, is investigated by using synchrotron X-ray multiscale tomography during SPS of alumina granules at 1300°C. While large defects arising from the hierarchical granule packing structure cannot be removed by pressureless sintering, crack-like defects and branched rodlike defects are almost eliminated by SPS at stresses higher than 30 and 50 MPa, respectively. But, small ellipsoidal porous regions, which may arise from aggregates or dimples of granules, cannot be removed even at a pressure of 50 MPa. A very large defect is also found by using micro-CT. It is supposed that this defect is formed from a large void in loosely packed granules. The shrinkage of large voids and the elimination of crack-like defects are explained by the theoretical prediction based on the continuum theory of sintering.

All-solid-state lithium-ion batteries are promising next-generation secondary batteries, primarily because of their superior safety. In their production process, it is necessary to achieve large contact interfaces between the particles and improve particle fluidity. The particle shape of the solid electrolyte plays a key role in addressing these requirements. Li₃PS₄ (LPS) is synthesized in the liquid phase and offers the advantages of cost-effectiveness and production scalability. However, the mechanisms controlling particle size and shape have not yet been revealed. In this study, we synthesized LPS particles in the liquid phase using a hot stirrer and an ultrasonic homogenizer to investigate the effects of reaction temperature and impact force on the reaction time and particle shape. We successfully synthesized shape-controlled particles with high ionic conductivity by combining different synthesis methods. This study provides valuable data for optimizing the synthesis conditions to attain specific particle shapes and sizes.

Porous structures are increasingly getting attentions in developing environmental catalysts, such as three-way catalysts (TWC), due to their ability to improve catalyst performance without changing their composition. This study explored various template-to-TWC mass ratios to create an optimal interconnected nanoporous structure while maintaining the catalyst morphology. This optimized sample was then investigated to compare CO oxidation performance with nanoparticles and aggregate structures. The results demonstrated that the nanoporous structure improved CO oxidation efficiency by 50% compared with other structures. This improvement is attributed to the better diffusion of reactants within the interconnected porous structures of the nanoporous sample. These findings highlight the critical role of nanoporous structures in enhancing the effectiveness of environmental catalysts.

Several types of metal–organic frameworks (MOFs) exhibit S-shaped adsorption isotherms due to their structural expansions. These materials are obtained as powder samples and require molding for industrial use; however, molding the samples with polymer binders reportedly made the S-shape less distinct. Our previous study elucidated this mechanism: the polymers inhibited the volume expansion of MOFs in the pellets. In this study, we molded two types of flexible MOFs exhibiting different volume expansion ratios and compared their adsorption behaviors. We concluded that a flexible MOF with a smaller volume expansion suppresses the smeared effect when in pellet form.