Recently, new thermal insulation materials with lower thermal conductivity than conventional insulation materials, such as ceramic fiber insulation, have been developed. However, due to the problems such as heat resistance, their practical use is limited to only below 800°C. In this paper, the thermal conductivity of fumed silica compacts was repeatedly measured less than 1200°C, and the thermal insulation performance was evaluated. As a result, it revealed low thermal conductivity in the range of 0.034 W/(m·K)–0.051 W/(m·K) between 200°C and 900°C. Heat processing at 900°C did not change the thermal conductivity of the processed compact, but increased the compressive strength to about 1.7 times compared to as-received compact. On the other hand, the thermal conductivity increased by the repeated heat processing. However, its thermal conductivity after heat processing at 1100°C was lower than that of fumed alumina compact after heat processing at 1200°C. The thermal conductivity significantly increased after heat processing at 1200°C. The increase of thermal conductivity by the repeated heat processing was explained by the rise of solid heat flux due to the increase of bulk density of the compact adding to the increase of aggregated structure area among nanoparticles in the compact.

The sustained-release formulations consist of many components, such as the active pharmaceutical ingredient, excipient, binder, lubricant, and polymer, leading to the complex dissolution process. The objective of this study is the elucidation of the rate-determining step in the dissolution process by direct optical observation. The composite particles of hydroxypropyl methylcellulose (HPMC) and brilliant blue FCF (model drug) were prepared, and the direct observation of the dissolution process and image analysis were conducted. The decrease in particle size and the penetration of solvent into the particles during the dissolution process had little impact on the sustained-release performance. On the other hand, the diffusion rate of the model drug in the HPMC gel strongly depended on the type of HPMC, suggesting that the rate-determining step in the dissolution process of the sustained-release formulations using HPMC would be the drug diffusion process in the polymer gel in the particles.

This review gives a numerical simulation method for the granular and multiphase flows in realistic porous media. We have developed a method to coordinate the three-dimensional microstructure obtained by scanning a fibrous filter with X-ray computed tomography with computational fluid dynamics simulations. We developed wall boundary models to represent the microstructure with complex shape. The immersed boundary method was used for the existence of solid regions in the fluid. To represent the wettability in the free-interfacial flow, we employed a method based on the phase-field model to set the order parameter in the solid region according to the wettability. The signed distance function constructed by solving the reinitialization equation was used to calculate the contact force with the solid surface in the granular flow. Typical results of the computations with the present numerical simulation methods are present.

Surface chemical modifications of nanoparticles at solid state in vacuum at extremely low temperature without catalyst and solvent are shown. Mechanical destruction of polymer in vacuum at 77 K produced a naked-activated-mechano-radical which was induced by homogeneous scission of covalent bond composed of polymer main chain and a naked-activated-mechano-anion and a naked-activated-mechano-cation which were induced by heterogeneous scission of covalent bond. Each was tethered on the fresh surface produced by the mechanical destruction. It initiated radical polymerization or cationic polymerization, produced a block copolymer and resulted in surface modification by the block copolymer. Another surface modification was performed by a novel covalent bond formation between naked-activated-mechano-anion and naked-activated-mechano-cation due to physical contact.