In winter, electric power facilities such as solar panels, substations, power towers, and power lines suffer from freezing or ice accumulation problems due to exposure to harsh external environments. These problems result in unstable power supply, high maintenance costs, and severe economic and social losses. To address these problems, diverse anti-icing or deicing techniques including physical, thermal, and chemical approaches have been developed. However, these conventional approaches have limitations such as requirements for additional external energy, environmental toxicity, and low applicability. Recently, novel anti-icing surfaces based on unique drop bouncing dynamics have been developed by mimicking nano/micro-structures of natural systems. These anti-icing surfaces have attracted attention due to their high energy efficiency and environmental friendliness. It has been found that the superhydrophobic surfaces with specific nano/micro-structures can effectively remove the water droplets before the formation of ice nucleation by minimizing contact area and contact time between the droplets and the surface, thereby demonstrating excellent anti-icing properties. This review introduces recently developed anti-icing techniques based on the drop bouncing dynamics, and briefly describes the future direction of the anti-icing technology for stable power supply.

A separator used by marine engine functions as a purifier by dividing engine oil into pure oil and impurities. By rotating the separator at a high speed between 1800 to 4500 rpm, fine particles of oil inside the separator are centrifuged due to the weight difference when the engine oil is refined. The impurities, so-called sludge, should be manually removed by taking the separator apart from the oil purifier system unless the accumulated sludge is measured and monitored in real time. A manual discharge of the sludge causes an increase of cycle time to clean the engine oil as well as operator exposure of safety risks. Therefore, the development of automatic system with a sludge monitor and an actuator is necessary for ship engine efficiency. In this paper, the pressure difference from the accumulated sludge is monitored via a pressure sensor. By measuring the pressure exerted at the wall surface, the amount of sludge was quantitatively estimated within the error of 0.032-0.091 kg when the oil purifier system has been automated.

The cold forging Process applies surface lubricant coating in order to smooth the friction during the cold forging process. Currently, most of the lubrication processes apply the zinc phosphate coating, which requires 11 steps and disposes sludge. But the water based lubrication process, which has been newly developed, takes 3 steps only and does not cause sludge. In this study, we present the optimal condition of water based lubrication for the cold forging of axle shaft by an experimental design method. Experimental results with minitab shall be able to predict the optimum water based lubricating conditions for the cold forging processes