• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.67-72
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• 2013

The flash point is the lowest temperature at which there is enough concentration of flammable vapor to form an ignitable mixture with air. The flash point is a major physical property used to analyse the fire and explosion hazards of a flammable liquid solution. The flash point data for pure components are easily available in several literature. But the flash points of the flammable binary solutions appear to be scarce in the literature. The objective of this study is to measure and estimate the flash point of acetic acid-formic acid system. Cleveland open cup tester was used to measure the flash point. The experimental data were compared with the values estimated by the Raoult's law and the optimization methods based on van Laar and Wilson equations. As a result, the estmated values by optimization methods were found to be better than those based on the Raoult's law.

• Journal of the Korean Institute of Gas
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• v.19 no.4
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• pp.8-14
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• 2015

For the safe handling of 2-methyl-1-butanol being used in various ways in the chemical industry, the flash point and the autoignition temperature(AIT) of 2-methyl-1-butanol was experimented. And, the lower explosion limit of 2-methyl-1-butanol was calculated by using the lower flash point obtained in the experiment. The flash points of 2-methyl-1-butanol by using the Setaflash and Pensky-Martens closed-cup testers measured $40^{\circ}C$ and $44^{\circ}C$, respectively. The flash points of 2-methyl-1-butanol by using the Tag and Cleveland open cup testers are measured $49^{\circ}C$ and $47^{\circ}C$. The AIT of 2-methyl-1-butanol by ASTM 659E tester was measured as $335^{\circ}C$. The lower explosion limit by the measured flash point $40^{\circ}C$ was calculated as 1.30 Vol.%. It was possible to predict lower explosion limit by using the experimental flash point or flash point in the literature.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.820-829
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• 2017

Vegetable oil dielectrics have been used in transformers as green alternatives to mineral insulating oils for about twenty years, because of their advantages of non-toxic, biodegradability, and renewability. However, the viscosity of vegetable oils is more than 3 times of mineral oils, which means a poor heat dissipation capacity. To get low-viscosity dielectrics, transesterification and purification were performed to prepare vegetable oil methyl esters in this study. Electrical and physical properties were determined to investigate their potential as dielectrics. The results showed that the methyl ester products had good dielectric strengths, high water saturation and enough fire resistance. The viscosities (at $40^{\circ}C$) were 0.2 times less than FR3 fluid, and 0.7 times less than mineral oil, which indicated superior cooling capacity as we expected. With the assistance of 0.5 wt% pour point depressants, canola oil methyl ester exhibited the lowest pour point ($-26^{\circ}C$) among the products which was lower than FR3 fluid ($-21^{\circ}C$) and 25# mineral oil ($-23^{\circ}C$). Thus, canola oil methyl ester was the best candidate as a low-viscosity vegetable oil-based dielectric. The low-viscosity fluid could extend the service life of transformers by its better cooling capacity compared with nature ester dielectrics.

• Journal of the Korean Institute of Gas
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• v.14 no.5
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• pp.19-25
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• 2010

The flash points for the systems, o-xylene+n-pentanol and m-xylene+n-hexanol, were measured by using Tag open-cup tester(ASTM D1310-86). The experimental data were compared with the values calculated by the Raoult's law and the optimization method using van Laar and Wilson equations. The calculated values based on the optimization method were found to be better than those based on the Raoult's law. The predictive curve of the flash point prediction model based on the van Laar equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the Wilson equation.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.29-33
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• 2006

Estimation of process safety is important in the chemical process design. Prediction for flash points of flammable substances used in chemical processes is the one of the methods for estimating process safety. Flash point is the property used to examine the potential for the fire and explosion hazards of flammable substances. In this paper, multivariate statistical analysis methods(partial least squares(PLS) quadratic partial least squares(QPLS)) using experimental data is suggested for predicting flash points of flammable substances of binary systems. The prediction results are compared with the values calculated by laws of Raoult and Van Laar equation.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.76-80
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• 2014

The flash point is one of the most important physical properties used to determine the fire hazard of flammable liquid mixture and defined as the lowest temperature at which a liquid produces sufficient vapor to form a combustible mixture with air. The main purpose of this paper is to measure and predict the flash point of binary flammable miscible mixtures. The flash points for n-hexanol+n-butyric acid and n-butanol+propionic acid, were measured by using Seta-flash closed cup method. The experimentally derived data were correlated with the binary interaction parameters of the van Laar and NRTL equations through the optimization method. The flash points estimated by these correlations were compared with those calculated by the method based on Raoult's law. The optimization method were found to be better than the method based on the Raoult's law.

• Progress in Superconductivity and Cryogenics
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• v.15 no.4
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• pp.10-14
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• 2013

We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80 % of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.515-524
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• 2016

The purpose of this study was to identify how safety awareness and self-efficacy affect the safety practice with elementary school students. The participants were 369 elementary school students(4~6th grade) in Changwon city. Data were collected using self-report questionnaires and analyzed with the SPSSWIN 22.0 program. Analysis methods were t-test, one way ANOVA, Scheffe test, Pearsons correlation coefficient and multiple linear regression. As a results, safety awareness was an average 2.97 point which was moderate levels and self-efficacy was on over intermediate level of an average 3.73 point. Safety practice was an 3.00 point. Safety practice had statistically significant difference according to grade, number of family, mother's education, character and school life attitude. Safety awareness(r=.41, p<.001) and self-efficacy(r=.39, p<.001) was significant correlation with safety practice. Fire safety(${\beta}=.22$, t=3.56) and self-efficacy(${\beta}=.27$, t=5.32) were significantly influenced safety practice and explaining 24.0% of the variance. From the results of this study, I proposed the education programs to increase safety practice in elementary school students that emphasizes self-efficacy and safety awareness.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.4
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• pp.12-23
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• 2001

The research focused on the landscape of mountains and hills drawn in a landscape picture. The purpose of the research is to classify patterns of landscape drawning in landscape pictures and to clarify the characteristics of the pattern by a quantitative index. We selected 21 landscape pictures to understand the Landscape Setting Here(LSH) and Landscape Setting These(LST). We investigated size quantitative indices using 1 landscape picture. The index is a follow: altitude, Visual Distance, Angles, Angle of Appearance Size, Inclination, and Angle of Incidence. The following results were obtained by using this data. 1) It has been understood that we offer an important city view because the LSH of this research can establish understanding of the city structure. 2) We dividing 3 patterns by the LST space drawn in the landscape picture. 3 patterns are Ferry point, Beauty point, an Signal-fire point. 3) We clarified the landscape characteristics of each pattern and the characteristics between patterns by using the index according to this pattern. 4) We understood the problem concerning the Seoul city landscape examining the pattern of this research with the ordinance of Seoul city. It is necessary to standardized a system of pattern classification utilized in landscape pictures to establish a universally interpreted detailed quantitative index, which can be applied to research.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.60-65
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• 2014

The flash point is the major physical property used to characterize the fire hazard of flammable liquid solutions. In the present study, the main focus is on measuring and estimating the flash points for binary flammable mixture. The flash points for n-propanol+propionic acid were measured by Seta flash closed cup apparatus. The experimental data were correlated with the van Laar and NRTL equations through the optimization method. The results estimated by these correlations were compared with the values calculated by the method based on Raoult's law. The optimization method were found to be better than the method based on the Raoult's law.