Particulate matter (PM) pollution demands air filters that combine high efficiency with low pressure drop. Here, we report a self-powered electrostatic filter based on an electrospun cationic microfiber web of Chimassorb 944 (C-fiber). The C-fiber functions as a triboelectric nanogenerator (TENG), generating a surface charge density of 85.8 μC/m2 when paired with polytetrafluoroethylene (PTFE), which creates a strong electrostatic field for capturing sub-micron particles, including the most penetrating particle size (MPPS). As a result, the triboelectrically charged C-fiber filter maintains >80% filtration efficiency at a high wind speed of 60 cm/s, far exceeding uncharged mechanical filters (<20%) while retaining low air resistance. Kelvin probe force microscopy (KPFM) visualizes the surface-potential change after particle capture, and the gradual decay of TENG output provides a built-in indicator of dust loading. This strategy offers a promising platform for next-generation smart air purification systems.

The effect of plastic board drains (PBDs)on ground improvement was checked out considering three crucial factors: ground settlement, undrained shear strength, and residual water head. First, the settlement analysis including initial settlement induced by reclamation of sand mat was conducted by back calculation analysis with measured data. Its result showed toot the PBDs used for this site worked well on improving soft ground. Secondly, the undrained shear strength was investigated by laboratory and in-situ tests including unconsolidated-undrained triaxial compression (UU) tests, unconfined compression tests, in-situ vane tests, and cone penetration tests. From the test results, they showed that the undrained shear strength of the improved ground by PBDs was significantly increased as well as the strength increasing ratio especially 10~15m below the ground surface on site. Thirdly, the residual water head measurement from the in situ dissipation test was found the same as the static water head, which indicated primary consolidation was completed and the effect of soil improvement with PBDs can be confirmed.