Air filter filtration efficiency is determined by the particle capture-to-pressure drop ratio. We produced a melt-blown nonwoven fabric with a specific fiber diameter distribution by blending thick fibers using nozzles with different diameters. When a polycarbonate was extruded from large holes, the particle transmittance rate doubled and the pressure drop decreased by 1/3. Consequently, the quality factor increased by 1.5-fold. Most of the fibers in a pure polypropylene sample had diameters below 20 µm, even when the polypropylene was extruded from large holes. However, when polycarbonate was extruded, the distribution widened to 40 µm, and the proportion of fibers in the 20‒40 µm range increased. The pore size distribution followed a similar tendency of fiber distribution. Analysis of the fibers with diameters above 20 µm revealed that the fiber volume fraction widened markedly in the thickness direction. That is, a greater number of thick fibers ensures more air passages, thereby decreasing the pressure drop. The thick fibers form large pores, which increases the length of the flow paths of the aerosols. This increases the probability of particles contacting the fibers and suppresses particle penetration. The changes described above explain the increase in the quality factor.

A planar solid oxide fuel cell (SOFC) uses current collectors positioned between the cell and the interconnector. To address the cell deformation that occurs during extended operation of large SOFCs, we developed a novel flexible current collector made from a triple plain weave of Ni yarn. We characterized the properties of this triple plain weave and compared them with those of commercially available collectors using the Kawabata evaluation system at room temperature, as well as test methods for SOFC components at elevated temperatures. The triple plain weave demonstrated superior compression and recovery properties along the thickness direction compared to commercial collectors, such as single plain weaves and porous metals. The triple plain weave's flexibility was consistent at both low and high temperatures. Although the conductivity of the triple plain weave was lower than that of other collectors, the SOFC's output performance with this weave was higher than that with a single plain weave. Thus, triple plain weaves can enhance SOFC cell size and extend their lifespan.