• Proceedings of the SCSK Conference
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• 1992.09a
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• pp.5-26
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• 1992

Many methods of in vitro SPF evaluation have been developed in order to measure SPF of sunscreen products. In this study, we compared two spectrophotometric in vitro measurements using the skin cast made of Luviset CAP- $X^{R}$ resin and Transpor $e^{R}$ tape as substrate with two in vivo measurements using guinea pig and human. And we also observed the radiation reaching on the earth's surface in Seoul for one year and the change of the primary skin irritancy along the change of SPF value. According to the our research, the first, in vivo measurement using guinea pig had the close agreement with SPF measurement using human and showed the tendancy that guinea pig SPF was lower than human SPF. The second, there was the good relationship between in vitro SPF by using Transpor $e^{R}$ tape and in vivo SPF, and it is possible to predict human SPF from Protection Index(PI) by using tape. The third, it is thought that SPE 20 is reasonable value because of UV intensity in Seoul and the primary skin irritancy of higher SPF than 25. So we propose that it is important to distinguish the sunscreen product having higher than approximate 25 from the category of general cosmetics including lower SPF sunscreen product.oduct.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.1
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• pp.63-66
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• 2008

Sunscreen is usually used by people when they are at the beach or outdoor swimming pools. Since the existing methods of and standards for measuring the effects of blocking ultra violet rays do not employ water resistance test methods, the establishment of a water resistance SPF test method is required. In this study, to standardize the SPF evaluation methods for a water resistant sunscreen, proposed measurement methods in this study were compared with those of foreign countries. Selected water resistance SPF experiments confirmed the product's suitability and a verification test was then conducted by establishing the variables of water resistance SPF measurement methods. In the comparative experiment on water resistance SPF given a water temperature of $23{\sim}32$ degrees centigrade showed that temperature did not have any statistically significant effect on water resistance SPF. The changing water flow also did not have any statistically significant effect on the water resistance SPF. Therefore, continuous 20 min water circulation is deemed appropriate as an alternative to the subject's usual activity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.1
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• pp.31-38
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• 2015

Geothermal heat pump (GHP) systems have become an efficient alternative to conventional cooling and heating methods due to their higher energy using efficiency. These systems use the ground as a heat source in heating mode operation and a heat sink in cooling mode operation. The aim of this study is to evaluate the heating performance of the GHP system for a residential building ($420m^2$) in Ulaanbaatar, Mongolia. In order to demonstrate the feasibility of a sustainable performance of this system, we installed the water-to-water geothermal heat pump with ten vertical ground heat exchangers and measured operation parameters from October 19, 2013 to March 26, 2014. The results showed that the entering source temperature of brine from the ground heat exchangers was in a range of the design target temperature of $-10^{\circ}C$ for heating. For total values of the representative results, the ground heat exchangers extracted heat of 53.51 MWh from the ground. In addition, the GHP system supplied heat of 83.55 MWh to the building and consumed power of 30.27 MWh. Consequently, the average heating seasonal performance factor ($SPF_h$) of the overall system was evaluated to be 2.76 during the measurement period of the heating season.