• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.2058-2065
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• 2004

A light collecting probe named Multi-color Integrated Cassegrain Receiving Optics (MICRO) is applied to spark-ignited spherical spray flames to obtain the flame propagation speed in freely falling droplet suspension produced by an ultrasonic atomizer. Two MICRO probes are used to monitor time-series signals of OH chemiluminescence from two different locations in the flame. By detecting the arrival time difference of the propagating flame front, the flame propagation speed is calculated with a two-point delay-time method. In addition, time-series images of OH chemiluminescence are simultaneously obtained by a high-speed digital CCD camera to ensure the validity of the two-point delay-time method by the MICRO system. Furthermore, the relationship between the spray properties measured by phase Doppler anemometer (PDA) and the flame propagation speed are discussed with three different experimental conditions by changing the fuel injection rate. It was confirmed that the two-point delay-time method with two MICRO probes is useful and convenient to obtain the flame propagation speed and that the flame propagation speed depends on the spray properties.

• 한국안전학회지
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• 제19권3호
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• pp.20-25
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• 2004

In order to obtain the flame Propagation speed in freely falling droplet suspension Produced by an ultrasonic atomizer, a light collecting probe named Multi-color Integrated Cassegrain Receiving Optics (MICRO) is applied to spark-ignited spherical spray flames. Two MICRO probes are used to monitor time-series signals of OH chemilumine-scence from two different locations in the flame. The flame propagation speed is calculated by detecting the arrival time difference of the propagating flame front. In addition, time-series images of OH chemiluminescence are simultaneously obtained by a high-speed digital CCD camera to ensure the validity of the MICRO system. Furthermore, relationship between the spray properties measured by phase Doppler anemometer (PDA) and the flame propagation speed are discussed with k different experimental conditions by changing the fuel injection rate. It was confirmed that the MICRO probe system was very useful and convenient to obtain the flame propagation speed and that the flame propagation speed was different depending on the spray properties.

• 한국전자통신학회논문지
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• 제6권4호
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• pp.479-485
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• 2011

비디오 기반 화염 감지 기법은 입력 비디오 영상에서 화염과 비슷한 색상을 가지고 움직임이 있는 영역에 대해서 화소 단위로 화염의 특성을 가지고 있는지를 시간적, 공간적 특징 분석을 통하여 확인한다. 비디오 기반 화염 감지 기법 연구의 가장 중요한 부분 중 하나는 화염 감지 성능이 저하되지 않고 어떻게 거짓 경보의 빈도를 줄일 수 있는가 하는 것이다. 기존의 방법들은 전기 장치로 만들어진 불빛들 중에서 자동차 전조등과 같은 일반적인 움직임을 가진 전기 불빛에 의한 거짓 경보는 쉽게 제거하고 있다. 그러나 경광등, 경고등 그리고 네온사인과 같이 깜빡거림이 있는 전기 불빛은 색상과 시간적, 공간적인 특징이 실제 화염과 비슷할 경우 거짓 경보를 발생시키는 요인이 되고 있다. 본 논문에서는 경광등, 경고등 그리고 네온사인과 같이 깜빡거림이 있는 전기 불빛 화소들의 주기 신호 검출을 통하여 진짜 화염이 아님을 확인하는 거짓 경보 제거 기능을 갖춘 비디오 화염 감지 기법을 제안한다. 실험 결과 화재 감지 성능은 기존의 방법과 비슷하였으나 기존의 방법이 거짓 경보를 발생시키는 시험 비디오에서 거짓 경보가 발생되지 않음을 볼 수 있었다.

• Journal of Biosystems Engineering
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• 제24권5호
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• pp.407-414
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• 1999

To evaluate the quality of flame-peeled chestnuts, their physical and chemical properties were analyzed. The physicochemical properties of flame-peeled chestnuts, including geometrical shape, texture and chemical composition, were compared to those of hand-peeled ones. For the flame-peeled chestnuts, some properties in heated and non-heated sections were separately analyzed. The color, texture such as springness, cohesiveness, adhesiveness, hardness and chewiness, moisture content, and reducing sugar of the heated section of the flame-peeled chestnuts were significantly different with their non-heated section. But the physicochemical properties of the non-heated section of the flame-peeled chestnuts were similar to those of the hand-peeled ones.

• 한국표면공학회지
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• 제38권2호
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• pp.83-87
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• 2005

We enhanced the color of blue sapphires and rubies successfully by using a oxygen-propane torch flame annealing, which had not been employed so far. We confirmed that about 1 mm-thick de-coloring of the corundum samples were available with 60 minutes flame annealing through eye evaluation, color coordination characterization, and methylene iodide immersion observation. We also suggest that the color centers such as $[Fe_{Al}^{\cdot}]$ may transform into transparent $[Fe_{Al}^{x}],\;[Cr_{A1}^{x}]$ sites with $[V_o^']$ generation at the elevated temperature in oxygen-rich atmosphere by diffusion mechanism. Our results implied that the longer diffusion time and the higher oxygen partial pressure might lead to the better de-coloring enhancement in corundum gem stones.

• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.41-45
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• 2011

본 논문에서는 컬러 화재영상에 포함된 화염의 색상 분석과 시공간적 특징 분석을 통하여 신뢰성 높은 화재 판정 조건을 제시한다. 이를 위하여 컬러영상에서 화염을 판정하는 컬러속성으로서 Y-휘도 성분과 Cr-색차 성분을 조합한 문턱치를 도출하고 화염 후보영역을 선정하였다. 선정된 화염 후보영역에 대해서는 화염의 공간적인 질감분석과 시간적인 동적변화를 DCT와 프레임간 휘도성분 변화량을 분석하여 최종 화염 판정 기준으로 제시하였다. 컴퓨터 모의실험을 통하여 제시한 화염 판정 조건의 신뢰성과 실용성을 검증하였다.

• 대한기계학회논문집B
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• 제23권9호
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• pp.1172-1177
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• 1999

Comparisons of measured turbulence properties in the unburned gas region of turbulent premixed flame stabilized by pilot flame, in cases of combusting and non-combusting flow conditions, are presented. Methane-air premixed jet at fuel equivalence ratio of 0.6 and 1.0 and Reynolds number of 7,000 was diagnosed using two-color laser velocimeter to obtain turbulence statistics. Same set of measurements was repeated at 21 locations within the unburned gas region of both combusting and non-combusting conditions. Velocity data were analyzed to evaluate the spatial distribution of turbulence properties including Reynolds stress, probability densities, joint probability densities and auto correlations. Contrary to assumptions of current theoretical models, significant influence of flame was observed in every property that was studied in the present investigation. The effective viscosity increased ten-fold when flame was on from cold flow values. The effect of mixing on joint probability as well as in turbulence intensity was suppressed by the flame. The measurements suggest that common assumptions of premixed flame model may result in sizable error in prediction of flame length and temperature distribution in near-field.

• 융합신호처리학회논문지
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• 제20권3호
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• pp.159-164
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• 2019

영상정보에서 색상만을 이용하여 산불을 감지하는 것은 매우 어려운 이슈이다. 본 논문은 산불을 포함하고 있는 동영상에서 영역의 색상과 움직임을 분석하여 산불영역을 감지하는 알고리즘을 제안한다. 제안하는 알고리즘에서는 조명 상태에 의존하지 않고 배경 영역을 추출 가능한 가우시안 믹스쳐 기반의 배경 분할 알고리즘을 이용하여 제거한다. 또한 RGB채널을 HSV채널로 변경하여 색상 기반으로 화염 후보들을 추출한다. 그렇게 추출된 화염후보들은 라벨링 및 트래킹을 하면서 면적이 일정하면서 이동하면 화염이 아니라고 판단한다. 이런 방법으로 추출된 화염후보 영역들이 2분 이상 같은 위치에 있으면 화염으로 판단한다. 구현된 알고리즘을 이용하여 실험한 결과 그 유효성을 확인하였다.

• 에너지공학
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• 제6권2호
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• pp.162-169
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• 1997

The particle size effect on the combustion characteristics of pulverized coal was investigated in the cylindrical-shape, horizontal furnace, fired in the range of 8.8∼10.6 kw. Three differently-sized fractions (5, 30, and 44 microns in average diameter) of high-volatile bituminous coal, were burned in the test furnace. Burnout behavior of pulverized coal flame were determined through the measurement of stable species concentrations (CO$_2$and H$_2$O). Concentrations of CO$_2$were compared with the theoretical values and the result showed good agreement. Thermal behavior of pulverized coal flame were determined as maximum flame temperatures occurred at fuel-rich conditions in every case. Flame lengths were also determined by decreasing with the particle size decrease. The flame length of the fine sized coal sample was comparable to that produced by distillate oil. The color of the coal flames ranged from orange to yellow, with the flame of the fine size fraction being brighter and yellower than the others.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.177-185
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• 2007

The temperature and soot of the visualized diesel engine's turbulent flow of flame was qualitatively measured. In combustion chamber, in order to judge the affect that the swirl has on the in-cylinder's current, was used two different heads with different values. Using the high speed camera, and the results were analyzed using the heat release rate produced by the pressure sensor. In order to measure the temperature and soot of the turbulent flames like that of the diesel flames two color methods were used temperature and the soot of the flames according to the conditions through analyzing the two wavelengths of the flames. It was possible to measure the highest temperature of the non-swirl head visualized engine which is approximately 2400K, and that swirl head engine managed up to 2100K. With respect to the visualized diesel engine soot, we got the grasp of the KL factor which bears the qualitative information of soot. This study is dedicated to suggesting the possibility of measuring not only the temperature but also soot of the diffusion flame of the diesel engine turbulent flames through such method.