• 한국환경복원기술학회지
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• 제4권3호
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• pp.1-9
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• 2001

The purpose of this study was to evaluate the burning impacts of the surface and crown fire occured in yongsan-ri meongsok-myun of chinju-city, Gyeongnam. Environmental influences like surface runoff and soil erosion changes were investigated by comparisons analysis between burned and unburned area about some initial effects after fire. The results obtained from this study were as followed; 1. The average amount of surface runoff in burned area was more 1.7 times than in unburned area. But it was gradually tend to decrease in burned area as times passed. 2. Factors significantly correlated to amount of surface runoff in burned area shown in order to unit rainfall, accumulated rainfall and sand content, as 0.9466 of multiple correlation coefficient, where as the factors in unburned area were unit rainfall, soil erosion, bulk density and soil hardness, as 0.9738 of multiple correlation coefficient. 3. The average amount of soil erosion in burned area was more 11.2 times than in unburned area. But it was gradually tend to decrease in burned area as times passed. 4. Factors significantly correlated to amount of soil erosion in burned area were surface runoff and unit rainfall, as 0.6305 of multiple correlation coefficient. The factors in unburned area shown in order to surface runoff, sand content, bulk density and unit rainfall, as 0.7879 of multiple correlation coefficient.

• 한국제4기학회지
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• 제16권2호
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• pp.1-8
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• 2002

본 연구에서는 1995-2001년에 고성지방의 산불 다발생지 10개 지역을 대상으로, 산불발생의 인위적 요인과 기상요인을 파악하였다. 그 결과를 요약하면 다음과 같다. 같은 곳에서 산불이 3회 이상 발생한 곳은 거진읍 거진리, 간성읍 선유실리, 죽왕면 마좌리 등이고, 인접지역에서 계속, 산불이 3회 이상 발생한 곳은 토성면의 학야리, 성대리, 인흥리 등이다. 1995-2001년에 산불발생 퐁 46회 중, 3월 11회, 4일 11회, 11월 7회, 1월 6회, 2일 6회, 12일 3회, 10일 2회 등이고, 산불발생이 많은 시간은 11-18시이다. 산불 발생원인은 군사훈련, 논.밭두렁소각, 쓰레기소각, 농산물폐기물 소각, 성묘객실화, 담뱃불, 방화 등인데, 군사훈련과 군부대내의 쓰레기 소각으로 인한 산불발생이 제일 많았다. 산불이 제일 많은 3,4월, 산불 발생 22일의 일평균 최고기온은 일평년값보다 $5^{\circ}C$높았고, 일평균상대습도는 23% 낮았으며, 일평균풍속은 0.8m/s강했다. 그리고 3,4월에는 퓐의 특성을 가진 강풍이 자주 나타난다. 이때, 한반도 중심의 기압배치는 $\ulcorner$남고북저$\lrcorner$형이다.

• 한국수소및신에너지학회논문집
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• 제25권1호
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• pp.47-58
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• 2014

The characteristics of flame shape, laminar burning velocity, emissions and heat flux of stagnation point in premixed impinging jet flame of syngas fuel with 10% hydrogen content were experimentally investigated. Also, the adiabatic temperature and burning velocity are calculated by Chemkin package with USC-II mechanism. The equivalence ratios(0.8~5.0) and dimensionless separation distance(2.0~5.0) with fixed Reynolds number(1800) are main parameters in this work. Different flame shapes and colors were observed for different impingement conditions. The experimental results of burning velocity by flame surface area have a consistent with previous works and numerical simulation of this work. The inner flame length could be predicted with the ratio of mixture velocity and burning velocity from a simple formulation by the laminar burning velocity definition. It has been observed that the heat fluxes at stagnation point are directly affected by the flame shape including the separation distance. The emission results in impinging flame of syngas fuel show that the characteristics of $NO_x$ emission traced well with adiabatic temperature trend and CO emission due to fuel rich condition increased continuously with respect to the equivalence ratio.

• IEIE Transactions on Smart Processing and Computing
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• 제2권3호
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• pp.117-129
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• 2013

The increasing demand for monitoring wildfires and their impact on the land surface have prompted studies of burned area extraction and analysis. To differentiate burned and unburned area, the earlier method of the Moderate Resolution Imaging Spectro-radiometer (MODIS) Burned Area Detection Algorithm was proposed to estimate the change in land surface based on the reflectance energy. The energy, whose wavelengths are sensitive to burning, was selected to calculate the change parameter $Z_{score}$. This method was applied using the MODIS images to produce a MODIS Burned Area product. The approach was to simplify this algorithm to make it compatible with the Landsat 7 ETM+ SLC-off images. To extract the refined version of burned regions, post-processing was carried out by applying a median filter, dilation morphology algorithm, and finally a gap filling method. The experimental results showed that the detailed burned areas extracted from the proposed method exhibited more spatial details than those of the MODIS Burned products in the large U.S areas. The results also revealed the discontinuous distribution of burned regions in Vietnam forests.

• 한국항공우주학회지
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• 제35권12호
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• pp.1108-1114
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• 2007

end-burning 연소실의 주요 설계인자들을 구축하기 위해 기존에 수행되었던 인젝터 배열 및 포트 직경 변화, O/F비 변화 외에 산화제 분사각 변화에 따른 연소 특성을 해석하였다. 연료면과 평행한 분사각(Case 1), 연료면을 향해 기울여진 분사각(Case 2)과 노즐을 향해 기울여진 분사각(Case 3)을 설정하여 모델을 구성하였다. 연료면을 향한 분사각의 경우 상류에서 가장 효율적인 혼합특성을 보였으나 상당량의 미연가스가 노즐 밖으로 배출됨을 알 수 있었다. 반면 Case 1과 Case 3은 낮은 혼합특성을 보였으나 연소효율은 연료면을 향한 경우보다 월등한 것으로 판명되었다. Case 1, Case 3 모두 유사한 경향을 나타내었으나 노즐을 향한 Case 3은 짧은 체류시간으로 인해 연료면과 평행한 Case 1에 비해 낮은 연소성능을 갖는 것으로 평가되었다.

• Journal of Forest and Environmental Science
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• 제33권3호
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• pp.172-186
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• 2017

The effects of application of fuel-reduction treatment in wildfire management has not been tested in dry forests of Ghana. Therefore, the short-term ecological effects of prescribed burning and hand thinning treatments followed by experimental wildfire were investigated in degraded forests and Tectona grandis forest plantations in two forest reserves of different levels of dryness in Ghana. The results showed that more trees were killed in prescribed burning (average of 41% in degraded forest and 18% in plantations) than hand thinning (7.2% in degraded forests and 8% in plantation). More tree seedlings were also killed in prescribed burning (72%) than hand thinning (47%). The mortality of trees and seedlings were greater in Worobong South forest, a less dry forest reserve than the Afram Headwaters forest, a drier forest reserve. Fuel treatment especially prescribed burning compared to the control reduced wildfire effects on forest canopy particularly in the less dry forest and tree mortality especially in the drier forest. Prescribed burning temporarily increased pH, exchangeable potassium (52%) and available phosphorus (82%) in the surface soils of the entire plots. The two fuel treatment methods did not have much influence on basal area, organic matter and total nitrogen. Nevertheless, they were able to reduce the adverse wildfire effects on soil pH, exchangeable potassium, available phosphorus, organic matter and total nitrogen concentrations. Fuel treatments therefore have potential application in dry forest management in Ghana due to their ability to retain important forest ecological traits after a wildfire incidence.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.102-108
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• 2006

On the refutation demanded for a control of various toxic substances. PCBs(poly chlorinated biphenyl) has a fatal poisonous matter in the ecosystem and the environmental pollution as it Is a kind of stable chemical substance. Especially, the gross Product of PCBs is estimated at about one million tonnage all over the world. However it is kept on storing in untreated state, then has a deterioration by the Prolonged storage and a risk of overflowing. Therefore, this research examined the fundamental characteristics of combustion and emission for the target of using the IPA (iso-propyl alcohol) solution as a part of PCBs control. IPA was filled to three kinds of Vessel, i.e. Vessel I, II, and III, and then was investigated as follows combustion shape, flame temperature. mass burning velocity, and PM(Particulate matter). A radial thermometer and a C-A thermocouple measured the flame temperature, and the optical extinction method by using He-Ne laser and the filter weight method used in the PM measurement. As a result, with an increasing of L/S ratio, the flame length become shorter and the burning velocity is more rapid, but the particulate matters is higher. It is supposed that the air flow rate is high on Vessel. and then the combustion is Promoted in the surface area of the upstream zone. The future works plan to investigate the characteristics with an using of the mixing of IPA and PCBs

• 한국환경과학회지
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• 제12권7호
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• pp.783-789
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• 2003

This study was conducted to reuse the rice straw ash as washing agent for oil contaminated soils. The results are summarized as follows. The physical characteristics of rice straw before and after burning were as follows ; In case of burning rice straw 1g, the rice straw ash was generated 0.14g and pH was changed neutrality into alkali(pH 10.9) and specific surface area was increased to five times and particle distribution was corresponded to fine silt.(under 0.05mm) The physical characteristics of rice straw ash were Carbon 10.9%, Hydrogen 1.5%, Oxygen 23.4%, Nitrogen 5.2%, Sulfate 1.2% and chemical characteristics were Si 189.2ppm, Ca 10.2ppm, Mg 4.7ppm. Oil cleanup ratio by pH variation were about 40∼50% of initial concentration of oil by pH 10∼11. As the result of cleanup comparative experiment, the rice straw ash was about 20∼30%, the tritonX-100 about 40∼50% of washing efficiency, and then in the future it will be possibility of substitute washing agent.

• 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.

• 한국추진공학회지
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• 제27권1호
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• pp.17-26
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• 2023

Star 형상을 갖는 추진제 그레인은 다양한 면적 선도가 가능하고, 제작이 용이하여 실제 고체 추진제 로켓에 유용하게 적용될 수 있다. 그러나, 설계와 관련한 형상 변수가 많고 연소 말기 슬리버가 존재하므로, 해석 비용이 저렴한 일반적인 단일 최적화 기법으로는 최적 설계가 성공하기 어렵다. 본 연구에서는 활용성과 설계 성공률을 높이기 위해 데이터베이스를 사용하여 star 그레인을 설계하는 기법을 제안하였다. 제안된 방법에서는 성능 변수를 정의하고, 데이터베이스를 구축한 후 요구조건을 만족하는 해를 탐색한다. 제안된 방법을 적용하여 다양한 종류의 연소 면적 선도를 갖는 star 그레인의 설계를 수행하고, 설계 방법의 타당성을 검증하였다.