• Journal of the East Asian Society of Dietary Life
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• v.21 no.4
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• pp.526-534
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• 2011

Cold air drying was conducted on steamed chestnut-sweet potato to improve its quality, convenience, and preference as snack. Steamed sweet potato was dried from 10 to $25^{\circ}C$ for 48 hours, and moisture contents, colors, texture, and taste were evaluated. The lowest moisture content was 4.53% at $25^{\circ}C$. Lightness decreased while other color values (a, b, and ${\Delta}$E) increased with increasing drying temperature and drying time. Reducing sugar and soluble solid contents ranged from 93.22~190.35 mg/g and 17~60 $^{\circ}Brix$, respectively. The highest hardness of chestnut-sweet potato was 25.13 kgf/$cm^2$, and springiness and cohesiveness were 88.60, and 94.87%, respectively, when dried at $25^{\circ}C$ for 48 hours. Sensory evaluation score was highest at $20^{\circ}C$ for 24 hours. The optimum drying conditions were determined to be $19^{\circ}C$ and 39.5 hours by RSM(response surface methodology).

• Fire Science and Engineering
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• v.22 no.1
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• pp.99-104
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• 2008

It is important to understand thermal characteristic as a method to estimate the new materials, because spontaneous ignition characterized by causing combustion in the low temperature without ignition source. If can not find out the thermal characteristics of materials, it is frequent that causes of fires could not be found. The danger level of spontaneous ignition material should be estimated and by closely studying its thermal characteristic. However, RPF(Refuse Paper & Plastic Fuel) is a solid matter and getting increasesa year by year because it is an economy profit as alternative energy for limited fossil fuels. Some time RPF occur a fire in the cases of its production process and conservation. Therefore study for thermal stability and critical ignition temperature of RPF was so imperative that the experiment by means of Bombe Calorimeter, TG-DTA, MS80, SIT-II, and Wire Basket Test was implemented. As a result, RPF had a caloric value 26.4-28.3 MJ/kg, and its initial pyrolysis temperature was $192^{\circ}C$ at heating rate 2 K/min. With the result of analysis by MS 80 which is an instrument measuring microscopic calory, pure RPF not containing water has higher caloric value than RPF containing 20% water. Also, SIT-II which is an instrument of insulated auto-ignition was ignited by $118.5^{\circ}C$. This temperature is lower than that of Wire Basket Test. The critical ignition temperature was calculated by Frank-Kamenetskii equation can cause ignition at $80^{\circ}C$ when conserved in the height of 10 m by the standard of infinity slab.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.543-560
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• 2010

Safety-related concrete structures in a nuclear power plant must be protected against the impact of flying objects, referred to in the profession as missiles. In practice, the structural verification is usually carried out by means of empirical formulas, which relate the velocity of the impinging missile to the wall thickness needed to prevent scabbing or perforation. The purpose of this study is to reevaluate the predictability of the local effect prediction formulas for the penetration and scabbing depths and perforation thickness. Therefore, available formulas for predicting the penetration depth, scabbing thickness, and perforation thickness of concrete structures impacted by solid missiles are summarized, reviewed, and compared. A series of impact analyses is performed to predict the local effects of the projectile at impact velocities varing from 95 to 215 m/s. The results obtained from the numerical simulations have been compared with tests that were carried out at Kojima to validate numerical modelling. The simulation results show reasonable agreement with the Kojima test results for the overall impact response of the RC slabs. From these results, it seems that the Degen equation give a very good estimate of perforation thickness against a tornado projectile for test data. Finally, the results obtained from the impact analysis have been compared with Degen formula to determine the perforation thickness of the RC slab.