• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.493-502
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• 2012

Syngas laminar burning velocity measurements were carried out at atmospheric pressure and ambient temperature using the Bunsen flame configuration with nozzle burner as a fundamental study on flame stability of syngas fuel. Representative syngas mixture compositions ($H_2$:CO) such as 25:75%, 50:50% and 75:25% and equivalence ratios from 0.5 to 1.4 have been conducted. Average laminar burning velocities have been determined by the stabilized nozzle burner flames using the angle method, radical surface area method and compared with the data obtained from the other literatures. And the results of each experimental methodologies in the various composition ratios and equivalence ratios were coincided with the result of numerical simulation. Especially, it was confirmed that there was necessary to choice a more accurate measurement methodology even the same static flame method for the various composition ratios of syngas fuel including hydrogen. Also, it was reconfirmed that the laminar burning velocities gradually increased with the increasing of hydrogen content in a fuel mixture.

• 대한기계학회논문집B
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• 제20권1호
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• pp.244-254
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• 1996

Flow velocity was measured by, use of hot wire anemometer. Turbulence intensity was in proportion to mean flow velocity regardless of swirl velocity. And integral length scale has proportional relation with swirl velocity regardless of measurement position. Turbulent burning speed during flame propagation which was determined by flame photograph and gas pressure of combustion chamber was increased with the lapse of time from spark and was decreased a little at later combustion period. Because of combustion promotion effect, turbulent burning speed was increased according to increase of turbulence intensity. Burning speed ratio i.e. ratio of turbulent burning speed ($S_BT$) to laminar burning speed ($S_BL$) was found out by use of turbulence intensity u' and integral length scale $l_x$ , $\delta_L$ is width of preheat zone in laminar flame.

• Journal of Oral Medicine and Pain
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• 제47권3호
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• pp.109-116
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• 2022

Purpose: This study was conducted to analyze the clinical characteristics and distribution of the tongue-related diagnoses in patients with tongue symptoms. Methods: The subjects were patients who visited Chosun University Dental Hospital with tongue symptoms from January 1, 2021, to December 31, 2021. We analyzed 491 patients (139 males and 352 females) with tongue-related diagnostic code names in the Korean Standard Classification of Disease (KCD) in the Electronic Medical Record (Dentopinformation Technology Co., Seoul, Korea). Results: On analyzing the diagnoses of tongue diseases using the KCD, glossopyrosis (44.8%) and painful tongue (15.2%) showed high rates. Of the 491 patients, 139 (28.3%) were males and 352 (71.7%) were females, and the average age was 58.1 years. As for systemic diseases, there were many patients with diseases of the circulatory system (27.0%) and endocrine, nutritional, and metabolic diseases (13.7%). Tongue symptoms were discomfort in 58 patients, pain in 329 patients, paresthesia in 10 patients, burning sensations in 222 patients, dysgeusia in 25 patients, dryness in 110 patients, fissures in 57 patients, and other symptoms in 72 patients. Areas with tongue symptoms were the anterior area in 102 patients, the lateral area in 140 patients, the posterior area in 12 patients, the dorsal area in 140 patients, the ventral area in 42 patients, and which area in 126 patients overall. Patients with burning mouth syndrome and oral candidiasis had significantly more tongue symptoms. Conclusions: Patients with tongue symptoms exhibited a variety of tongue diseases. Tongue symptoms were more common in women over 50 years of age and were frequently seen in patients with burning mouth syndrome and oral candidiasis.

• 한국대기환경학회지
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• 제16권1호
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• pp.11-22
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• 2000

Polycyclic aromatic hydrocarbons(PAHs) have known as potentially hazardous air pollutants(HAPs0 to human health because of its carcinogenic and mutagenic behaviors. The purpose of this study was to determine the level of 6 PAHs(Fluoranthene, Pyrene, Benzo[a]anthracene, Chrysene, Benzo[b]fluoranthene, and Benzo[a]pyrene) as well as 10 inorganic elements(Cr, Na, K, Zn, Pb, Fe, Cu, Ti, Al and Cd) in the ambient PM-10. The total of 115 samples had been collected from February, 1996 to June, 1996 on quartz fiber by a PM-10 high volume air sampler near the Yong-Tong Apartment complexes. A statistical analysis was performed for the PAHs and inorganic elements data set using a principal component analysis in order to identify qualitatively the potential sources of PM-10. A total of 6 principal components were separated by intensive data pretrement and transformation processes, such as soil, refuse incineration, oil burning, coal burning, field burning, vehicle emission sources. The results showed that PAHs were associated with various burning activities like refuse and field burning, coal burning, and oil burning emissions in the study area. These derived sources were well matched with the previously known source profiles in terms of compositonal order and level of measured species. The combination data set consisted of both organic and inorganic species might provide more powerful source signature and might increase the number of potentially derived sources than PAHs or inorganic data alone.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.79-84
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• 2003

The main objective of this study was to investigate the chemical characteristics of post-harvest biomass burning aerosols from field burning of barley straw in late spring and rice straw in late fall in rural area in Korea. 12-hr integrated intensive sampling of $PM_{10}$ and $PM_{2.5}$ biomass burning aerosols had been conducted continuously at Gwangju, Korea 4-15 June 2001 and 8 October-14 November 2002. The fine and coarse particles of biomass burning aerosols were collected for mass, ionic, elemental, and carbonaceous species analysis. Average fine and coarse mass concentrations of biomass burning aerosols were measured to be 129.6, 24.2 ${{\mu}gm}^{-3}$ in June 2001 and 47.1, 33.2 ${{\mu}gm}^{-3}$ in October to November 2002, respectively. Exceptionally high level of $PM_{2.5}$ concentration up to 157.8 ${{\mu}gm}^{-3}$ well above 24-hour standard was observed during the biomass burning event days under stagnant atmosphere condition. During biomass burning periods dominant ionic species were $Cl^{-}$, ${NO_3}^{-}$, ${SO_4}^{2-}$, and ${NH_4}^{+}$ in fine and coarse mode. In the fine mode $Cl^{-}$ and ${KCl}^{+}$ were unusually rich due to the high content of the semiarid vegetation. High OC values and OC/EC ratios were also measured during the biomass burning periods. Increased amount of fine aerosols with high enrichment, which were originated from biomass burning of post-harvest agricultural waste, resulted in extremely severe particulate air pollution and visibility degradation in the region. Particulate matters from open field burning of agricultural wastes cause great adverse impact on local air quality and regional climate.

• 한국환경과학회지
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• 제4권2호
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• pp.195-220
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• 1995

A lot of sludges occur during an activated sludge treatment process of the washing wastewater and by-product waste in the cuttlefish processing manufacture. The sludges give also out a bad smell, and their amicable reclamation is very difficult because of the limited area of the filling-up. To reduce the heavy weight and large volume of the sludges, they was burning up. After the burning up at 350t for 2hrs the weight(volume) of the sludges were reduced to 5% level of the initial value. In contents of the bad heavy metals for human after the burning up, cadmium and lead metal were slightly detected, while mercury and the bad others not detected.

• Journal of Ecology and Environment
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• 제36권1호
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• pp.101-112
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• 2013

To quantitatively analyze the effects of burning, we conducted a vegetation survey in the grasslands in Kirigamine, central Japan. We classified each species into stages of succession based on the life-history traits of the species and defined the score of the species in each stand based on the classification. We weighted the scores with a v-value, the product of coverage and height in the quadrat, and summed them to calculate the index of dynamic status. With these indices, we were able to quantitatively compare the stands in the study area and discern minute differences between the stands with different lengths of restoration periods since the disturbance of burning. These indices correlated with the v-value of trees, suggesting that the disturbance of burning seemed to affect the trees in the stand. We then calculated the growth of the tree species Pinus densiflora to evaluate its contribution to the index of dynamic status.

• 한국세라믹학회지
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• 제27권2호
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• pp.211-218
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• 1990

CA2-based clinker with highly activated surface and hydraulic properties was synthesized at a comparatively lowr temperature than that of conventional synthesis by "hydration-burning method". This consists of calcining the mixture of CaCO3 and Al2O3 to obtain a primary clinker, hydrating the primary clinker and reburning the hydrates to obtain final clinker. Burning of primary clinker above 1200℃ was necessary to eliminate free CaO in it and to obtain it's solid hydrate. However, rising the burning temperature above 1300℃ is ineffective due to the decrease in hydraulic properties of the primary clinker with the temperature. Hydration of primary clinker at the elevated temperature(>35℃) was required to obtain the hydrate with more porous structure and final clinker with more active surface. CA2 was formed and increased with temperature at above 1150℃, finally became a primary phase of the final clinker. However, burning at the temperature above 1300℃ resulted in reverse effect on the hydraulic properties of the final clinker due to rapid decrease in it's surface area with the temperature.

• 대한설비공학회지:설비저널
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• 제15권1호
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• pp.97-104
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• 1986

This is to supply the basic data for saving energy and the appropriate way of waste disposal. The amount of waste disposed and its heat after burning is guessed to get conclusions. 1. The amount of disposable waste in 1990 in Seoul area is expected to be 2.2kg per man/day, coal ashes (YONTAN) 0.7kg, non-coal ashes 1.5kg. 2. The amount of waste combustible and heat after burning will be increased, and it is useful when the waste has Less than $70\%$ of water. 3. The method to collect waste should be specially organized, because most of the waste collected In Korea Is wet. 4. As the heat emitted from mass burning is $4\times10^{12}kcal/y$ in 1985, it is considered to be in senses of energy saving and the rationnal way of waste disposal. 5. Special concern is needed because the environment contaminated will be polluted in result of burning.

• 한국추진공학회지
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• 제26권2호
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• pp.12-19
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• 2022

금속선이 삽입된 추진제 그레인은 높은 충전율을 유지하면서 연소속도를 증가시키기 위해 사용되어왔다. 금속선이 삽입된 추진제 그레인을 사용하는 추진기관의 성능설계를 위해서는 금속선의 위치, 개수, 배치각도, 금속선에서의 추진제 연소속도 증가비에 따른 burn-back 해석이 요구된다. 본 연구에서는 금속선이 삽입된 추진제 그레인의 설계변경에 대응하여 신속하게 연소면적을 계산할 수 있는 수치적 방법이 개발되었다. 개발된 방법과 CAD 프로그램으로부터 도출된 연소면적 결과를 비교하였으며, 격자의 반경방향 크기가 줄어들수록 오차율이 줄어드는 것을 확인 했다. 금속선의 개수 및 위치변경에 따른 영향성 분석이 수행되었으며, 금속선의 개수가 증가하면 연소초기 및 말기 구간이 짧아지고 정상상태구간이 길어지는 것이 확인되었다. 금속선을 배치할 때, 서로 다른 반경에 금속선을 배치하는 경우에서 동일한 반경에 금속선을 배치하는 경우보다 연소초기 영역에서의 연소면적이 급증하고 연소말기에서 연소면적이 급감하는 것이 확인되었다.