The study of the effects of the ultraviolet radiation on tofu as a skin tissue mimicking material

The UV radiation index in the city of Yogyakarta, recorded by AccuWeather at bright sunshine from 10 a.m. to 2 p.m., is overexposure, i.e., in the range from 4 to 9 UV Index scale. It reflects the moderate to high risk of sunburn on the human skin, caused by unprotected sun exposure. The purpose of this research is to find out the influence of UV radiation on tofu, a material acting as the replacement of the skin. The results of this research will be used to build a UV-based Early Warning System (EWS). The research was conducted using 7Ã�11-Watt neon lamps as UV artificial sources and tofu as a tissue mimicking material. The tofu was being exposed by UV radiation and the intensity of UV radiation emitted by artificial sources to the tofu was measured using an ML8511 UV radiation sensor. The linear relationship between intensity (in W.m ^-2 ) and UV exposure (in UV Index scale) were calibrated experimentally, covering the distance from 1 to 10 cm. The UV artificial sources were placed at 10 cm in front of the ML8511 UV radiation sensor. The effect of UV radiation exposure on the tofu colour after three hours exposure was recorded by a Nikon DSLR D600 and the effect of UV radiation on tofu temperature were measured using thermal camera DT9885. The results of ML8511 sensor testing show that it is reliable and eligible to be used as a sensor of UV exposure. The intensity of UV radiation (I, in W.m ^-2 ) decreases with the increase of distance (d, in cm) by following the equation: I = 0.2145 d ² -5.7587 d + 39.943 and vice versa the intensity increases with the increase of power (P, in Watt) by following the equation: I = 0.00007 P ³ â�� 0.017P ² +1.4649P-0.0167. The results of this research also indicate that the UV artificial sources with an equivalent intensity of 9 UV index is energetic enough to deliver less heat and to break up a molecule that makes up the dye and finally, it causes fade the color gradually in a tofu skin. This overexposure could be avoided by reducing exposure to solar UV, i.e., avoid to stay outdoor at noon. If this is not possible, stay in the shade or wear clothes and wear wraparound sunglasses that block of UVA and UVB. © School of Engineering, Taylorâ��s University.