• 연구논문집
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• s.24
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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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.228-231
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• 2011

Burning rate of a propellent is an essential factor when designing a propulsion system. In order to come up with burning rate, first we need to design and build propellent grain to get neutral pressure curve. Then check the pressure with ground test and calculate the burning rate using burning rate equation. This burning rate is then compared to the burning rate of a propellent which was resulted from making a standardized specimen and combusting it using a strand burner. An accurate burning rate is calculated after comparing those two burning rates. For this study, compact propulsion system was designed, produced, tested and analyzed in order to get burning rates, an essential factor in propulsion system design, in an effective way.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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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.

• The Journal of Internal Korean Medicine
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• v.32 no.4
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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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• v.18 no.8
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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.

• Journal of the Korean Society of Safety
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• v.7 no.3
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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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• v.36 no.2
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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.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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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.

• Fire Science and Engineering
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• v.28 no.2
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• pp.34-39
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• 2014

It is necessary to enhance its availability and reliability of performance based fire design of building with various type of database such as experiments, survey and fire properties and so on. In order to utilize to the performance based fire design, the present study has been performed a series of experiments to investigate the burning characteristics of building materials for two types of interior board and three types of interior louver. The burning test has been also conducted for different thickness because it may show different characteristics of burning behavior such as flame spread rate and flame propagation time. The result shows that the effective heat release per unit mass of interior materials were almost constant with 15.3~16.9 MJ/kg regardless of its thickness while the peak heat release rate and maximum $CO_2$ concentration was varied with thickness.

• Journal of the Korean Society of Tobacco Science
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• v.17 no.1
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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.