In the experiment, three-dimensional net-structured alumina nanofibers were successfully prepared by spray-freeze-drying process for the first time with an average diameter below 100 nm. Alumina nanofibers were obtained from polyvinyl alcohol (PVA) and boehmite precursor nanofibers after calcination at 500 °C for 5 hours. At first, boehmite nanoparticles as a source of alumina were dispersed with 1 wt% PVA aqueous solution to form alumina nanofibers with different weight ratios of PVA and alumina. The best weight ratio of PVA and alumina (30:70) was selected on the basis of fiber morphology, nano diameter, thermal stability and precipitation of boehmite nanoparticles. This best weight ratio of PVA and alumina was applied again to form alumina nanofibers from PVA/boehmite precursor nanofibers which were prepared using 0.5, 0.1 and 0.01 wt% PVA aqueous solutions. The best alumina nanofibers were obtained when 0.1 wt% PVA solution was used. Here, average fiber diameter of alumina nanofibers was 79 nm along with more interconnected net-structure and higher specific surface area. Crystalline phase of alumina nanofibers was transferred from γ-alumina to α-alumina when calcination temperature increased from 500 °C to 1200 °C. Specific surface area and porosity of alumina nanofibers significantly decreased with the increase of calcination temperature.

Thermal resistance assessments of clothing are typically performed under still-air conditions; however, actual wearing environments require consideration of airflow effects. This study investigated women's suits of identical design differing solely in the air permeability of the outer-fabric, to evaluate thermal performance under still-air and airflow conditions using a thermal manikin. Under still-air conditions, minimal differences in mean manikin skin surface temperature were observed among the samples. In contrast, under airflow conditions, samples with higher outer-fabric air permeability exhibited greater decreases in mean manikin skin surface temperature. This tendency was particularly pronounced under the posterior airflow condition, whereas differences among samples were relatively small under the anterior airflow condition. These findings indicate that the influence of outer-fabric air permeability is difficult to detect under still-air conditions but becomes evident as differences in thermal performance under airflow conditions. These results suggest that evaluations conducted solely under still-air conditions may not fully characterize the thermal performance of garments under actual wearing conditions.

Smart insoles, particularly insole-type sensors, have attracted tremendous attention because they are promising candidates for analyzing motion in healthy individuals and patients. In this study, an insole-type sensor containing sensing parts of knits made of a conductive yarn was developed. The sensor continuously outputs AC currents/voltages without an external power supply while the sole of a person's foot contacts the sensing parts with and without a sock. The continuous output originates from currents/voltages in the body induced by ambient electromagnetic fields. Combining the insole-type sensor, wireless sound transmitters and receivers, and software application or program made it possible to detect continuously and wirelessly where the wearer's sole was touching or pressing and provide automatic notification when a person exits a room. The developed sensor can be used for, for example, assessing gait disturbance at an early stage or providing notification when a person with dementia exits a room.

Nanofiber dispersions were prepared by fibrillating poly (p-phenylene terephthalamide) (PPTA) fibers, followed by wet spinning and supercritical fluid drying to produce aerogel fibers. These aerogel fibers exhibited a distinct blue structural color due to Rayleigh scattering, highlighting their promise as structurally colored materials. However, their high porosity and low density resulted in insufficient mechanical strength, limiting practical applications. In this study, after wet spinning in an acrylic acid coagulation bath, the resulting gel fibers were immersed in a polymerization solution using acetone as the solvent, methyl methacrylate (MMA) as the monomer, and 2,2-diethoxyacetophenone (DEAP) as the initiator. This solution was then irradiated with ultraviolet light to perform photoinitiated polymerization of methyl methacrylate (MMA) within a PPTA nanofiber network. This process formed a cross-linked reinforcing structure inside the aerogel fibers. Under optimal conditions (30 wt% MMA, 0.5 wt% initiator, 120 s UV irradiation at 100 % intensity), the reinforced aerogel fibers achieved a tensile strength of 1.68 cN/dtex while maintaining low density and enhancing the blue coloration. Compared with unreinforced fibers, the polymerized fibers exhibited suppressed shrinkage during supercritical drying, preserved fine microstructure, and maintained Rayleigh scattering centers, leading to increased blueness. The polymerization reinforced the fibrillar skeleton, resulting in higher breaking strength, greater strain at break, and lower Young's modulus. A clear trend was observed across parameters: higher tensile strength correlated with greater strain at break, lower density, and lower Young's modulus. Scanning electron microscopy after tensile testing suggested smaller microfibril diameters and increased crosslinking density. These results indicate that the reinforced aerogel fibers possess a hierarchical structure characterized by low initial density and Young's modulus, which allows progressive microfibril orientation and improved load transfer with increasing strain. This approach successfully achieved mechanical reinforcement while preserving the desirable structural color and low density of PPTA aerogel fibers.