• 연구논문집
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• 통권24호
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• pp.41-48
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• 1994

This experimental study deals with the extinguishiment characteristics of an oil pool flame using the water spray. The water through the six different atomizers is ejected over the freely burning pool flame in the quiescent surrounding air. Injection direction is vertical to the surface of oil in a small tank with a diameter of 100mm and a height of 10mm. In order to estimate quantitatively the extinction, the burning rate as well as the effective water flux are measured. The effective water flux is the amount of the water which reach the pool from the nozzle. The burning rate with the water spray increases until the injection pressure increases to reach some value, which gives the maximum burning rate, while the effective water flux without the flame decreases or does not change according to increasing of the injection pressure. This maximum burning rate is greater than 2.5 times of burning rate of the fire without the water spray. As a matter of the extinguishiment, it is found that the water drops of which size is too small can not extinguish the fire because too small drops does not reach the fuel surface.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.228-231
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• 2011

추진제의 연소속도는 추진기관을 설계할 때 반드시 필요한 요소이다. 추진제의 연소속도는 중립적 압력선도를 얻을 수 있는 추진제 그레인을 설계/제작하여 지상연소시험을 통해 압력을 확인하고 연소 속도 계산식의 계산을 통해 얻는다. 이렇게 얻어진 계산된 연소속도 값은 표준화된 추진제의 시편을 제작하여 스트렌드 버너에서 연소시켜 얻어진 추진제의 연소속도 값과 비교하여 정확한 연소속도 값을 확인하게 된다. 본 연구는 추진기관 설계에 필수요소인 추진제 조성에 따른 연소속도를 효율적으로 얻고자 소형 추진기관을 설계/제작/시험/분석 하였다.

• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.18-25
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• 2002

Research to discuss the fire performance of materials requires tools for measuring their burning characteristics and validated fire growth models to predict fire behavior of the materials under specific tire scenarios using the measured properties as input for the models. In this study, burning characteristics such as time to ignition, weight loss rate, flame spread, heat release rate, total heat evolved, and effective heat of combustion for four types of wood-based materials were evaluated using the cone calorimeter and inclined panel tests. Time to ignition was affected by not only surface condition and specific gravity of the tested materials but also the type and magnitude of heat source. Results of weight loss rate, measured by inclined panel tests, indicated that heat transfer from the contacted flame used as the heat source into the inner part of the specimen was inversely proportional to specific gravity of material. Flame spread was closely related with ignition time at the near part of burning zone. Under constant and severe external heat flux, there was little difference in weight loss rate and total heat evolved between four types of wood-based panels. More applied heat flux caused by longer ignition time induced a higher first peak value of heat release rate. Burning characteristics data measured in this study can be used effectively as input for fire growth models to predict the fire behavior of materials under specific fire scenarios.

• 대한한방내과학회지
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• 제32권4호
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• pp.473-486
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• 2011

Objectives : This study was designed to investigate the clinical characteristics and usefulness of comprehensive diagnosis of Yin-deficiency and heart rate variability in patients with burning mouth syndrome (BMS). Methods : We surveyed 30 burning mouth syndrome patients visiting the Oral Diseases Clinic of Kyung Hee University Oriental Medicine Hospital from April to September of 2011. The subjects were evaluated on self-assessed severity of burning mouth syndrome and xerostomia using visual analogue scale (VAS) score and Yin-deficiency condition (based on the 10-item Yin-deficiency questionnaire). Salivary function was measured by the unstimulated salivary flow rate (USFR), and heart rate variability (HRV) parameters were recorded by SA-2000E (Medicore Co., Ltd., Korea). Results : There were substantial significant positive correlations between burning sensation VAS scores in mouth and Yin-deficiency scores. There was significant negative correlation between xerostomia VAS score and USFR. Compared to the normal range of total power (TP) in HRV parameters, the burning mouth syndrome patients showed significant lower values of TP. Conclusions : The results of this study suggest that comprehensive diagnosis of Yin-deficiecny and HRV parameters are useful in diagnosing of burning mouth syndrome patients. Therefore, we assume that improvement of Yin-deficiency condition can be a potentially effective way to treat burning mouth syndrome.

• Journal of Mechanical Science and Technology
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• 제18권8호
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• pp.1338-1348
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• 2004

A simplified method that models the deflagration process occurring in closed or vented vessels is described. When combustion occurs within the spherical or cylindrical vessels, the flame moves spherically or segmentally to the vessel periphery. The volume and area of each element along the propagating flame front are calculated by using simple geometrical rules. For instabilities and turbulence resulting in enhanced burning rates, a simple analysis results in reasonable agreement with the experimental pressure transients when two burning rates (a laminar burning rate prior to the onset of instability and an enhanced burning rate) were used. Pressure reduction caused by a vent opening at predetermined pressure was modeled. Parameters examined in the modeling include ignition location, mixture concentration, vented area, and vent opening pressure. It was found that venting was effective in reducing the peak pressure experienced in vessels. The model can be expected to estimate reasonable peak pressures and flame front distances by modeling the enhanced burning rates, that is, turbulent enhancement factor.

• 한국안전학회지
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• 제7권3호
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• pp.73-82
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• 1992

This paper was concerned with the risk evaluation of oxidizing substances by burning test method. The samples were prepared the heaped cone-shaped mixtures of solid oxidizing sub-stance with sawdust, and ignition of the sample was made on contact with heating wire inside the combution chamber that the temperature and humidity of atmosphere can be kept at $25^{\circ}C$ and 60% respectively. Accordingly, it were measured the combustivity effect of mixing ratio and amount of sample weight on the burning rate. As a result of burning test of these samples, it could be noticed that the case when the sawdust has so and 30 wt.% in the mixing ratio shows effective combustivity, and as the amount of sample weight was increasing, It showed more rapid burning time. So the average burning time could be obtained by considering the weighting factors to the parameters of the mixing ratio and the amount of sample weight. Finally, it was compared with the effects of cation and anion of oxidizing substances and also applied analytically to the classification and evaluation of oxidizing sub-stances as dangerous goods.

• Journal of the Korean Wood Science and Technology
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• 제36권2호
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• pp.1-8
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• 2008

This study was performed to evaluate the burning characteristics of wood-based materials and the effect of surface treatment of fire retardant using cone calorimeter. Four types of wood-based materials, such as Plywood, Oriented Strand Board (OSB), Particle Board (PB) and Medium Density Fiberboard (MDF), were tested at a constant heat flux of $50kW/m^2$ to investigate the time to ignition, mass loss rate, heat release rate, effective heat of combustion, etc. In addition, each type of wood-based material was tested at the same heat flux after fire retardant treatment on the surface to evaluate the effect of this treatment on the burning characteristics. The surface treatment of fire retardant, by the amount of $110g/m^2$, delayed the time to ignition almost twice. However, it was indicated that heat release rate, mass loss rate, and effective heat of combustion were not significantly affected by fire retardants treatment for all types of wood-based materials.

• 한국세라믹학회지
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• 제53권2호
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• pp.241-245
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• 2016

The purpose of this study was to investigate the bloating mechanism of artificial lightweight aggregates with different sizes (ESA, effective surface area). Aggregates were produced using hard clay, stone sludge, and a bloating agent in order to observe the effect of the gradation of the artificial lightweight aggregates. Kerosene and amorphous carbon were used as bloating agent. The particle size of the produced aggregate ranged from 3 mm to 9 mm. With regard to the amount of bloating agent to be used, 2 ~ 6 parts by weight were used. The specific gravity, absorption rate, and the type of aggregates produced by rapid sintering at $1075{\sim}1200^{\circ}C$ were determined. Microstructures were observed. When ESA had a value of 1 or below, kerosene, which has a high burning rate, was found to be advantageous for use as a bloating agent. When ESA had a value of 1 or above, carbon, which has a relatively low burning rate was found to be an advantageous bloating agent. It is thought that kerosene is more advantageous, as ESA decreases, for the production of aggregates having low water absorption rate.

• 한국화재소방학회논문지
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• 제28권2호
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• pp.34-39
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• 2014

건축물의 성능위주 소방설계의 활용성 및 신뢰성을 향상시키기 위해서는 다양한 화재실험 및 조사 등을 통해 가연물의 연소물성에 관한 광범위하고 다양한 데이터베이스가 필요하다. 본 연구에서는 건축물의 성능위주 소방설계에 활용하기 위해 건축물의 내장용 판재 2종과 내장용 루버 3종을 대상으로 연소시험을 실행하여 연소발열특성 등을 파악하였다. 또한 내장용 판재는 그 두께에 따라 최대열방출률 등 연소발열성상에 차이가 발생할 가능성이 있으므로 판재의 두께에 따라 연소시험을 수행하였다. 실험결과 내장재 판재 및 루버의 단위연소량당 평균발열량은 15.3MJ/kg~16.9MJ/kg이었고, 내장용 판재의 평균최대열방출률과 평균최대이산화탄소 농도는 판재의 두께에 따라 차이가 있는 것이 확인되었다.

• 한국연초학회지
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• 제17권1호
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• pp.62-67
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• 1995

Deliveries of tar, nicotine and carbon monoxide in mainstream smoke decreased with increment of exogenous potassium content of tobacco. Potassium malate was more effective than potassium nitrate, potassium carbonate, potassium citrate and potassium oxalate for the reduction of carbon monoxide, but potassium nitrate was more effective than potassium palate, potassium carbonat, potassium citrate and potassium oxalate for the reduction of carbon in the case of nicotine. Puff count and burning rate were slightly changed with added potassium salts.