Until recently, solar energy has been considered as a promising regeneration energy source in the future. Solar cell wafer production involves ingot cutting, cleaning, and packaging processes. In this research, design, fabrication, and testing of a batch-type midsonic for cleaning solar cell wafers were carried out. To reduce the damage compared to conventional systems, we decided to use 400 kHz in a midsonic wave range, and we used far-field to obtain a more regular acoustic pressure. Finite element analysis with Ansys software predicted an anti-resonance frequency of 458 kHz for an ultrasonic waveguide, and the measured result of the fabricated system was 454 kHz with a 0.9% error. Acoustic pressures were measured, and the result confirmed regular and high distributions. Finally, cleaning tests were performed, and a 90% particle removal efficiency (PRE) was achieved at 900 W. Thus, the newly developed midsonic cleaning system can be considered to clean particles on solar cell wafers efficiently while preventing damage.

Due to the characteristics of domestic mountainous terrain, the tunnels are increasing. Therefore, an increased budget and more advanced equipment are required to maintain the tunnels cleanliness. As a study on shape optimization using the design of experiment, this paper assessed the design parameters affecting the maximum stress of an articulated hydraulic crane boom. As a result, the maximum stress of an optimized boom was 223.94 MPa at optimal factors. It showed an accuracy of 99.38% compared with the finite element analysis.