• 방재와보험
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• s.108
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• pp.30-35
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• 2005

배선기구는 오랜 시간이 경과하면 절연성이 저하하거나 접촉부분이 탄화되어 발열 또는 발화원이 될 수 있다. 절연재료의 파손, 이상전압에 의한 절연파괴, 허용전류를 넘는 과전류에 의한 열적열화 등은 절연내력이 점차지하하여 마침내 절연재료의 열화에 의해 발화의 원인이 되므로 상시 점검하고 주의를 기울여야 한다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.11a
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• pp.135-139
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• 2000

경제의 발전으로 인한 화학물질의 개발과 합성 등으로 새로운 물질들이 다양화됨으로서 화재에 대한 위험성이 날로 증대되고 있는 실정이다. 특히 산업현장에서 원료로 사용하거나 제품으로 만들어진 물질들이 착화원이 없음에도 불구하고 자연발화가 원인이 되어 화재폭발을 일으키는 사고가 빈번하고 있다. 자연발화에 관한 연구는 국내외적으로 진행되고 있지만 다종의 물질에 대한 연구에는 대단히 미흡한 실정이다. 그러므로 본 연구는 5사업장에서 생산되고 있는 HPMC에 대하여 자연발화에 대한 현상을 구명하여 이를 사용하는 작업장 등에 있어서 화재, 폭발의 예방에 대한 기초자료를 제공하고자 한다.(중략)

• Journal of Korean Institute of Fire Investigation
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• v.11 no.1
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• pp.29-62
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• 2007

본 연구는 국내의 가정에서 가장 많이 사용되고 있는 1조식전자동세탁기(이하 기기라 함)의 발화위험요소 중, 그 내부에 부속된 세탁조의 하부측을 경유하며 배선되는 전선(이하 하부배선이라 함)의 발화형태와 성상(性狀)을 조명하므로서, 예방대안과 원인조사의 요령을 구체적으로 제시하고자 하였다.

• The Safety technology
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• no.42
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• pp.34-34
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• 2001

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.292-304
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• 2023

Purpose: This study was conducted to obtain experimental data for the establishment of preventive measures against fire, as large and small fire accidents occur at production and storage sites of superabsorbent polymers developed for the convenience of daily life. Method: The sample container was fixed at 0.2m in both length and width, and was shaped into a rectangular cuboid with heights of 3cm, 5cm, 7cm, and 14cm to access an infinite flat plane. The sample container was fixed in the center of a thermostatic bath that was heated to a predetermined temperature according to a preset temperature control program. If the central temperature of the sample rose more than 20℃ above the set temperature, it was determined to have 'ignited', and if it remained similar to the set temperature, it was determined to have 'unignited'. Result: The critical autoignition temperature was calculated to be 212.5℃ for a sample container with a height of 3cm, 202.5℃ for 5cm, 192.5℃ for 7cm, and 177.5℃ for 14cm. The ignition induction time to reach the highest temperature was approximately 42hours for 3cm, 91hours for 5cm, 151hours for 7cm, and 300hours for 14cm. Conclusion:① As the size of the sample container increased, the autoignition temperature decreased and the ignition induction time to reach the highest temperature increased. ② The apparent activation energy was calculated to be 39.30kcal/mol, with a correlation of 99.5%.

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.280-291
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• 2023

Purpose: As fire accidents happen at the production and storage sites of superabsorbent polymers for convenience of daily life, an experimental study was conducted to secure basic data to establish practical preventive measures against them. Method: The sample container (20cm width × 20cm length) was made into a rectangular cuboid with the heights of 3cm, 5cm, 7cm, and 14cm, respectively, to allow access to the infinite flat plane. The front and back of the container were covered with a 300-mesh stainless steel mesh for one-dimensional heat transfer. The sample container was placed in the center of the thermostatic bath, which was heated to a predetermined temperature by setting the thermostat program in advance, and it was determined to be 'ignited' when the central temperature of the sample rose by more than 20℃ above the set temperature, and "unignited" when it was maintained at an approximate value of the set temperature. Result: The critical autoignition temperature was calculated to be 217.5℃ when the height of the sample container was 3 cm, 212.5℃ when it was 5 cm, 202.5℃ when it was 7cm, and 187.5℃ when it was 14cm. The ignition induction time to reach the maximum temperature was 34hours for 3cm, 76hours for 5cm, 143hours for 7cm, and 318hours for 14cm. Conclusion: ① As the size of the container increased, the autoignition temperature decreased and the induction time to reach the maximum temperature increased. ② An apparent activation energy was calculated to be 44.92kcal/mol, with a correlation of 96.93%.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.19-31
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• 2020

The purpose of this study is to observe the realization of pause and breath groups from adult speakers and to examine how gender, generation, and tasks can affect this realization. For this purpose, we analyzed forty-eight male or female speakers. Their generation was divided into two groups: young, old. Task and gender affected both the realization of pause and breath groups. The length of the pause groups was longer in the read speech than in the spontaneous speech and female speech. On the other hand, the length of the breath group was longer in the spontaneous speech and the male speech. In the spontaneous speech, which requires planning, the speaker produced shorter length of pause group. The short sentence length of the reading material influenced the reason for which the length of the breath group was shorter in the reading speech. Gender difference resulted from difference in pause patterns between genders. In the case of the breath groups, the male speaker produced longer duration of pause than the female speaker did, which may be due to difference in lung capacity between genders. On the other hand, generation did not affect either the pause groups or the breath groups. The generation factor only influenced the number of syllables and the eojeols, which can be interpreted as the result of the difference in speech rate between generations.

• Fire Science and Engineering
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• v.33 no.1
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• pp.7-14
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• 2019

While wood pellets are often used as a fuel in thermoelectric power plants and firewood boilers, there is a risk of ignition temperature when strong wood pellets, which have a high calorific value, for prolonged periods of time. In this research study, the minimum auto ignition temperature and the ignition limitation temperature according to the change in flow rate depending on the size of the test vessel were calculated, and based on these temperatures, the apparent activation energy was calculated to predict the combustive properties of the material. The apparent activation energy was calculated to be 190.224 kJ/mol. The thicker the sample is storage in the vessel, the longer the ignition induction time was due to the increased difficulty in heat being transferred from the surface of the vessel to the middle section area of the vessel. For vessel of the same size, the higher the flow rate, the lower the auto ignition temperature was. It was also confirmed that increases in the size of the test vessel lowered the auto ignition temperature and increased the ignition induction time.

• Phonetics and Speech Sciences
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• v.11 no.2
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• pp.33-44
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• 2019

This paper dealt with how realization of pauses in utterance is affected by speech style, gender, and generation. For this purpose, we analyzed the frequency and duration of pauses. Pauses were categorized into four types: pause with breath, pause with no breath, utterance medial pause, and utterance final pause. Forty-eight subjects living in Seoul were chosen from the Korean Standard Speech Database. All subjects engaged in reading and spontaneous speech, through which we could also compare the realization between the two speech styles. The results showed that utterance final pauses had longer durations than utterance medial pauses. It means that utterance final pause has a function that signals the end of an utterance to the audience. For difference between tasks, spontaneous speech had longer and more frequent pauses because of cognitive reasons. With regard to gender variables, women produced shorter and less frequent pauses. For male speakers, the duration of pauses with breath was significantly longer. Finally, for generation variable, older speakers produced more frequent pauses. In addition, the results showed several interaction effects. Male speakers produced longer pauses, but this gender effect was more prominent at the utterance final position.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.78-89
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• 2017

Spontaneous combustion propensity of various coals of carbonization grade as a pulverized fuel of coal fired power plant has been tested from an initial temperature of $25^{\circ}C$ to $600^{\circ}C$ by heated in an oven with air to analyze an self oxidation starting temperature. This tests produce a CPT(Cross Point Temperature), IT(Ignition temperature) and CPS(Cross Point Slope) by calculated as the slope of time taken a rapid exothermic oxidation reaction at CPT base. CPS show a carbonization rank dependence, whereby wood pellet has the highest propensity to spontaneous combustion of $20.995^{\circ}C/min$. A subbituminous KIDECO coal shows an CPS values of $15.370^{\circ}C/min$ whereas it of pet coke of the highest carbonization rank has $20.950^{\circ}C/min$. The nature of this trend is most likely a concentration of volatile matter and oxygen functional groups of coal surface that governs the available component for oxidation as well as surface area of fuel char, and constant pressure molar heat.