To develop high-performance de- or anti-frosting/icing devices based on transparent heaters, it is necessary to study the evaporation-rate control of droplets on heater surfaces. However, almost no research has been done on the evaporation-rate control of liquid droplets on transparent heaters. In this study, we investigate the evaporation characteristics of water droplets on transparent heater surfaces and determine that they depend upon the surface wettability, by modifying which, the complete evaporation time can be controlled. In addition, we study the defrosting and deicing performances through the surface wettability, by placing the flexible transparent heater on a webcam. The obtained results can be used as fundamental data for the transparent defrosting and deicing systems of closed-circuit television (CCTV) camera lenses, smart windows, vehicle backup cameras, aircraft windows, and sensor applications.

Thermal cracking of slender mass concrete in attached walls, retaining walls and bridge towers, is controlled by mainly using low heat cement and the control joint. However, it is impossible to control thermal cracks perfectly because the external restraint is largely in these mass concrete members. In this study, to control the thermal cracking of slender massive concrete structures, a new pipe cooling method, which is the vertical pipe cooling method, was developed and a mock-up of a wall-type mass concrete specimen was tested to investigate the validity of this method. Each pipe is connected to the header pipe, and a drainage control cap is installed at the upper end of each pipe. As a result, the hydration heat of the pipe cooling specimen was about 8-14°C lower than that of the non-pipe cooling specimen and the tensile stress generated was smaller in the pipe cooling specimen than in the non-pipe cooling specimen. In the specimen without pipe cooling, a penetrating crack with a maximum width of 0.40 mm and length of 1250 mm occurred in the middle of the specimen.

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In this study, we report for the first time on the convection phenomenon for the consistent and sensitive detection of target materials (particulate matter (PM) or gases) with a high-performance transparent heater. The high-performance transparent heater, based on Pt-decorated Ni micromesh, was fabricated by a combination of transfer printing process and Pt sputtering. The resulting transparent heater exhibited excellent mechanical durability, adhesion with substrates, flexibility, and heat-generating performance. We monitored the changes in the PM concentration and temperature in an airtight chamber while operating the heater. The temperature in the chamber was increased slightly, and the PM2.5 concentration was increased by approximately 50 times relative to the initial state which PM is deposed in the chamber. We anticipate that our experimental findings will aid in the development and application of heaters for sensors and actuators as well as transparent electrodes and heating devices.

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