• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.75-81
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• 2011

For the safe handling of cyclohexane, the explosion limit at $25^{\circ}C$ and the temperature dependence of the explosion limits were investigated. Flash point and AIT(autoignition temperature) for cyclohexane were experimented. By using the literatures data, the lower and upper explosion limits of cyclohexane recommended 1.0 Vol% and 9.0 Vol%, respectively. Moreover lower flash points of cyclohexane recommended $-20^{\circ}C$. It was measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for cyclohexane, and the experimental AIT was $255^{\circ}C$. The new equations for predicting the temperature dependence of the explosion limits of cyclohexane is proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.70-76
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• 2013

For the safe handling of styrene, this study was investigated the explosion limits of styrene in the reference data. The flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. As a results, the lower and upper explosion limits of styrene recommended 0.9 Vol.% and 8.0 Vol.%, respectively. The lower flash points of styrene by using closed-cup tester were experimented $29^{\circ}C{\sim}31^{\circ}C$. The lower flash points of styrene by using open cup tester were experimented $32^{\circ}C{\sim}36^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for styrene. The experimental AIT of styrene was $460^{\circ}C$.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.5-11
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• 2015

The explosion limit is one of the major combustion properties used to determine the fire and explosion hazards of the flammable substances. The explosion limit of aldehydes have been shown to be correlated the heat of combustion and the chemical stoichiometric coefficients. In this study, the lower explosion and upper explosion limits of aldehydes were predicted by using the heat of combustion and chemical stoichiometric coefficients. The values calculated by the proposed equations agreed with literature data above determination coefficient 0.99. From the given results, using the proposed methodology, it is possible to predict the explosion limits of the aldehydes.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.318-318
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• 2012

인도네시아의 Citarum 유역을 대상으로 구축된 RRFS를 이용하여 해당유역의 상류에 위치한 다목적 댐인 Saguling 댐에 대한 2005년 월 유입량예측을 수행하여 보았다. 실제 예측과정에는 ESP 기법을 적용하였고 여기에 기상전망을 고려할 수 있는 사전처리기법인 PDF ratio 방법을 이용하여 유출량 시나리오의 발생확률을 갱신하였다. 이를 위하여 대상유역의 월 강우량 관측 자료에 대한 초보예측을 통하여 2005년 관측 강우량에 따라 기상전망을 생성하였다. 또한 Saguling 댐의 월 유입량 과거 관측자료에 대한 초보예측을 통하여 High Flow, Normal Flow, Low Flow에 대한 예측구간을 구성하여 보았다. Fig. 1과 Fig. 2는 각각 ESP 기법과 PDF ratio 방법을 이용하여 산정한 Normal Flow와 Low Flow의 상한계 유입량의 발생확률의 변화를 도시한 것이다. 관측 유입량이 발생한 구간의 예측확률을 기반으로 예측점수를 산정해 본 결과 ESP 기법에 의한 예측점수가 0.333을 상회하고 있음을 볼 수 있었다. 이는 ESP 기법에 의한 예측결과가 초보예측보다 정확도가 높음을 의미하는 것으로 본 연구에서 구성한 ESP 시스템의 적용성을 확인할 수 있다. 또한 고무적인 결과로서 PDF ratio 방법에 의한 예측점수가 ESP 기법에 의한 예측점수를 상회하고 있음을 확인할 수 있다. 이는 ESP 기법에 의한 예측결과를 확률기상전망을 이용하여 갱신할 경우 예측 정확도를 개선시킬 수 있음을 의미하는 것이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.180-180
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• 2018

가능최대강수량(PMP)은 대규모 수공구조물의 설계 시 기준이 되는 강수량으로, 최근 대규모 거대재난에 대비한 대피계획수립에 PMP를 활용하려는 움직임이 있으며 PMP에 대한 국내 연구가 활발히 수행되고 있다. PMP를 추정하기 위해 Hershfield의 통계적 방법에 대한 간단한 대안이 제안되었다. PMP는 물리적인 강우량 상한계로, 확률론적 개념과는 모순적이다. 또한, Hershfield의 PMP는 연 최대 시계열 평균의 선형함수로 주어지는 모양 매개변수를 가지는 GEV 분포의 약 60,000년 빈도임이 밝혀졌다. 따라서 본 연구에서는 Hershfield의 방법을 확률론적으로 해석하는 것이 바람직할 것으로 판단하였고, 기상청 ASOS 및 AWS 자료를 이용하여 우리나라 각 지점자료 중 10년 이상의 자료를 사용하여 Hershfield 방법을 적용하여 PMP를 산정하였다. 각 지점의 빈도계수를 구하여 우리나라 자료에 적합한 확률분포의 형태를 적용하였고, 분포형의 매개변수 값을 추정하였다. 또한, Hershfield의 빈도계수와, 우리나라 자료에 해당하는 빈도계수가 몇 년 빈도로 계산되는지 각각 확인해 보았다. ASOS 및 AWS 자료를 이용하여 연 최대 강수량 시계열 평균과 모양 매개변수의 관계 공식 또한 구성하였다. 본 연구의 방법을 검증하기 위하여 우리나라에서 제일 오래된 자료(57년)인 서울지점 자료를 이용하여 경험적인 분포함수와 본 연구에서 제안하고 있는 방법을 비롯한 다양한 방법을 통하여 구한 분포함수를 비교하여 도시하였다.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.8-15
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• 2012

For the safe handling of isopropyl alcohol, the explosion limits were investigated. The lower flash points, upper flash points, fire point, and AITs(autoignition temperatures) by ignition time delay for isopropyl alcohol were experimented. By using literature data, the lower and upper explosion limits of isopropyl alcohol were recommended as 2.0 and 12.0 vol%, respectively. The lower flash points of isopropyl alcohol were experimented $12{\sim}14^{\circ}C$ by using closed-cup tester and $18{\sim}19^{\circ}C$ by using open cup tester. And the upper flash points of isopropyl alcohol was experimented $38^{\circ}C$ by using Setaflash closed-cup tester. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus was $463^{\circ}C$.

• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.33-39
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• 2006

For the safety design and operation of many gas process, it is necessary to know certain explosion limit, flash point, auto ignition temperature and minimum oxygen concentration of handling substances. Also it is necessary to know explosion limit at high temperature and pressure. For the safe handling of propane, explosion limit and autoignition temperature of combustion characteristics for propane were investigated. By using the literatures data, the lower and upper explosion limits of propane recommended 2.0 vol% and 10.0 vol%, respectively. Also autoignition temperatures of propane with ignition sources recommended $450^{\circ}C$ at the electrically heated cruicible fumace(the whole surface heating) and recommended about $960^{\circ}C$ at the local hot surface. The new equations for predicting the temperature and the pressure dependence of the explosion limits of propane are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.75-81
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• 2014

For the safe handling of isobutylalcohol(IBA), this study was investigated the explosion limits of isobutylalcohol in the reference data. And the lower flash points, upper flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. By using the literatures data, the lower and upper explosion limits of isobutylalcohol recommended 1.7 Vol% and 10.9 Vol.%, respectively. The lower flash point of isobutylalcohol by using Setaflash and Penski-Martens closed-cup testers were experimented $25^{\circ}C$ and $30^{\circ}C$, respectively. The lower flash point isobutylalcohol by using Tag and Cleveland open cup testers were experimented $36^{\circ}C$ and $39^{\circ}C$, respectively. Also, this study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for isobutylalcohol. The experimental AIT of isobutylalcohol was $400^{\circ}C$.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.1
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• pp.1-8
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• 2015

Recently, constructions of coastal structure including wind turbine structure have increased at southwest shore of Korea. There is a big difference of tide which rage from 3.0 m to 8.0 m at south and wet shore of Korea, respectively. In such ocean circumstance, large scour may occur due to multi-directional tidal current and transverse stress of the wind. therefore scour surrounding wind turbine structure can make system unsafe due to unexpected system vibration. In this study, hydraulic resistance capacity, i.e., critical velocity and critical shear stress, was evaluated by RCT. Uni-directional and bi-directional hydraulic resistance capacities of the samples which were consolidated by different preconsolidation pressures were correlated with soil resistivities of same samples. According to the correlation, it is possible to estimate hydraulic resistance capacity from electrical resistivity of soil. Through the updating the correlation for various soil types, it is expected that the hydraulic resistance capacity of whole construction site will be simply determined from the electrical resistivity.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.20-26
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• 2015

For the reliability of the combustible properties of arylic acid, this study was investigated the explosion limits of acrylic acid in the reference data. The flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower flash points of acrylic acid by using Setaflash and Pensky-Martens closed-cup testers were experimented in $48^{\circ}C$ and $51^{\circ}C$, respectively. The lower flash points of arylic acid by using Tag and Cleveland open cup testers were experimented in $56^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for acrylic acid. The AIT of acrylic acid was experimented as $417^{\circ}C$. The lower explosion limit(LEL) and the upper explosion limit(UEL) by the measured the lower flash point and the upper flash point of acrylic acid were calculated as 2.2 Vol% and 7.9 Vol%, respectively.