• 대한기계학회논문집B
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• 제33권8호
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• pp.613-621
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• 2009

Coal is the energy resource which is important with the new remarking energy resource. Coal combustion produces more NOx per unit of energy than any other major combustion technology. Pollutant emission associated with coal combustion will have a huge impact on the environment. Coal conversion has three processes which are drying, coal devolatilization and char oxidation. Coal devolatilization process is important because it has been shown that HCN which is converted from volatile N contributes 60 to 80% of the total NOx produced. This paper addresses mass release behavior of char, tar, gas and HCN in an experiment of Laminar Flow Reactor with two coals such as Roto middle coal (Sub-bituminous) and Anglo coal (Bituminous). The experiment is compared with the data predicted by CPD model for mass release of HCN about Roto south, Indominco, Weris creek and China orch coals. The results show that HCN increases as a function of decreasing the ratio of fixed carbon(FC)/ volatile matter(VM of the coals contain.)

• 한국연소학회지
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• 제21권4호
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• pp.30-38
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• 2016

Flame structure of co-firing coal and palm kernel shell (PKS) was investigated in a pulverized coal swirl burner by particle image velocimetry (PIV). The pulverized coal swirl flame is operated with a PKS blending ratio of 10%, 20%, and 30%. For all operating conditions, flame structures such as internal recirculation zone (IRZ), outer recirculation zone (ORZ), and exhaust tube vortex (ETV) were observed. In the center of flame, the strong velocity gradient is occurred at the stagnation point where the volatile gas combustion actively takes place and the acceleration is increased with higher PKS blending ratio. OH radical shows the burned gas region at the stagnation point and shear layer between IRZ and ORZ. In addition, OH radical intensity increases for a co-firing condition because of high volatile matter from PKS. Because the volatile gas combustion takes place at lower temperature, co-firing condition (more than 20%) leads to oxygen deficiency and reduces the combustibility of coal particle near the burner. Therefore, increasing PKS blending ratio leads to higher OH radical intensity and lower temperature.

• 한국환경과학회지
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• 제15권11호
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• pp.1011-1016
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• 2006

Recently, volatile organic compound(VOC) has been noted as a main cause of air pollution. VOC, with its toxic and offensive odor, is hazardous to health. Furthermore indoor, underground and hish-rise buildings are preferable living spaces. People spend more than 80% of the day indoor, so indoor air pollution is a matter of importance. In Korea, from 2004, 10 types of indoor pollutants in public facilities have been identified. However, there is no standard for individual VOC, so the regulation has not yet effectively been carried out. In this study, we have studied on the diffusion of Benzene in a room using a numerical analysis for various air-controlled conditions consisted of door, window and ventilation system. This study investigates spatial concentration distribution and time-history of room-averaged benzene concentration for several cases. The results of this study show that when the room is ventilated by a small fan only for 30 minutes, the average concentration of benzene is decreased a very little, thus the impact to human body would be serious compared to the case of natural ventilation by window and door, In the case of natural ventilation by window and door, if the wind speed is higher than 0.5m/s, it takes small than 4 minutes for benzene to spread to the target concentration of $1.2mg/m^3$.

• 대한기계학회논문집B
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• 제24권3호
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• pp.402-410
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• 2000

As the combustion process of CWM consists of the water evaporation, the release and combustion of volatile matter, and the combustion of char for every particle, it is more complex than that of existent liquid fuel. Though the many studies on CWM combustion have been carried out by the single droplet using hanging methods or the multiple droplet using atomization methods, any report don't presents definite solution about the effects by the initial water evaporation and combustion of volatile. When CWM is suddenly exposed in the high temperature surroundings, the internal water evaporates and then each droplet builds up pores. Besides, porosity rate changes along the temperature of surroundings, the composition ratio of CWM, and the initial diameter of droplet. In result, because it affects the whole combustion rate, the combustion of CWM has complex mechanism as compared with the combustion of liquid or gas fuel. Therefore, concentrating on porous structure of CWM, this study has proceeded to acquire the basic data on the CWM injection combustion and closely examines the effects of the first stage combustion on the whole combustion by measuring the diameter variations, pore rate, mass fraction burned, and the internal temperature changes of CWM droplet. The results demonstrate that $60{\sim}70%$ of initial mass is reduced during water evaporation and volatile combustion period, and swelling rate, mass faction burned, and density variation are greatly concerned with atomization of CWM etc.

• 한국축산시설환경학회지
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• 제4권2호
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• pp.167-174
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• 1998

It is known that the anaerobic fermentation of organic matter (OM) is divided into 2 phases, acidogenic phase in which OM is digested into volatile fatty acid (VFA), and methanogenic phase where the produced VFA is converted to CH4 and CO2. In a natural fermenting procedure, these 2 phases occur at the same time. However the total production of end products (methane) may be limited if these 2 phases occur at the same time. This is believed to be due to the difference in growth rate, substrate-utilizing efficiency and favorable environment for each microbes (acidogens and methanogens), involved in each phase. It is therefore suggested for the maximum recycling of organic waste (such as animal waste) through providing 2 different steps in fermenting procedure, acidogenic phase and methanogenic phase, in each case the activity of involved microbes can be maintained at the maximum level. The results obtained from these experiments are summarized as follows : The loading rates of swine waste were made through 2.5, 5 and 10 gVS / l / d to identify its acidogenic fermenting character in this study. The VFA yield was maximized at 10 gVS / l / d of loading rate. On the basis of this study was executed to identify the optimum HRT of 1, 2 and 4 days at 10 gVS / l / d of loading rate in acidogenic phase. The maximum VFA yield was obtained at 1 days of HRT.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7179-7188
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• 2015

Cancer is a major health obstacle around the world, with hepatocellular carcinoma (HCC) and colorectal cancer (CRC) as major causes of morbidity and mortality. Nowadays, there isgrowing interest in the therapeutic use of natural products for HCC and CRC, owing to the anticancer activity of their bioactive constituents. Boswellia serrata oleo gum resin has long been used in Ayurvedic and traditional Chinese medicine to alleviate a variety of health problems such as inflammatory and arthritic diseases. The current study aimed to identify and explore the in vitro anticancer effect of B. Serrata bioactive constituents on HepG2 and HCT 116 cell lines. Phytochemical analysis of volatile oils of B. Serrata oleo gum resin was carried out using gas chromatography-mass spectrometry (GC/MS). Oleo-gum-resin of B. Serrata was then successively extracted with petroleum ether (extract 1) and methanol (extract 2). Gas-liquid chromatography (GLC) analysis of the lipoidal matter was also performed. In addition, a methanol extract of B. Serrata oleo gum resin was phytochemically studied using column chromatography (CC) and thin layer chromatography (TLC) to obtain four fractions (I, II, III and IV). Sephadex columns were used to isolate ${\beta}$-boswellic acid and identification of the pure compound was done using UV, mass spectra, $^1H$ NMR and $^{13}C$ NMR analysis. Total extracts, fractions and volatile oils of B. Serrata oleo-gum resin were subsequently applied to HCC cells (HepG2 cell line) and CRC cells (HCT 116 cell line) to assess their cytotoxic effects. GLC analysis of the lipoidal matter resulted in identification of tricosane (75.32%) as a major compound with the presence of cholesterol, stigmasterol and ${\beta}$-sitosterol. Twenty two fatty acids were identified of which saturated fatty acids represented 25.6% and unsaturated fatty acids 74.4% of the total saponifiable fraction. GC/MS analysis of three chromatographic fractions (I,II and III) of B. Serrata oleo gum resin revealed the presence of pent-2-ene-1,4-dione, 2-methyl- levulinic acid methyl ester, 3,5- dimethyl- 1-hexane, methyl-1-methylpentadecanoate, 1,1- dimethoxy cyclohexane, 1-methoxy-4-(1-propenyl)benzene and 17a-hydroxy-17a-cyano, preg-4-en-3-one. GC/MS analysis of volatile oils of B. Serrata oleo gum resin revealed the presence of sabinene (19.11%), terpinen-4-ol (14.64%) and terpinyl acetate (13.01%) as major constituents. The anti-cancer effect of two extracts (1 and 2) and four fractions (I, II, III and IV) as well as volatile oils of B. Serrata oleo gum resin on HepG2 and HCT 116 cell lines was investigated using SRB assay. Regarding HepG2 cell line, extracts 1 and 2 elicited the most pronounced cytotoxic activity with $IC_{50}$ values equal 1.58 and $5.82{\mu}g/mL$ at 48 h, respectively which were comparable to doxorubicin with an $IC_{50}$ equal $4.68{\mu}g/mL$ at 48 h. With respect to HCT 116 cells, extracts 1 and 2 exhibited the most obvious cytotoxic effect; with $IC_{50}$ values equal 0.12 and $6.59{\mu}g/mL$ at 48 h, respectively which were comparable to 5-fluorouracil with an $IC_{50}$ equal $3.43{\mu}g/mL$ at 48 h. In conclusion, total extracts, fractions and volatile oils of B. Serrata oleo gum resin proved their usefulness as cytotoxic mediators against HepG2 and HCT 116 cell lines with different potentiality (extracts > fractions > volatile oil). In the two studied cell lines the cytotoxic acivity of each of extract 1 and 2 was comparable to doxorubicin and 5-fluorouracil, respectively. Extensive in vivo research is warranted to explore the precise molecular mechanisms of these bioactive natural products in cytotoxicity against HCC and CRC cells.

• 한국환경보건학회지
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• 제49권6호
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• pp.344-352
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• 2023

Background: With its developed port and related industries, the concentration of fine dust is high in Busan compared to other cities in South Korea. Many studies have reported the health effects of fine dust, but there has been a lack of information regarding concentrations of volatile organic compounds among those who exposed to high levels of fine dust. Objectives: This study aimed to define an area with high concentrations of particulate matter and perform biomonitoring surveys among the residents of the area. Methods: Air quality data was collected and the mean level of each district in Busan was derived. We then defined the area with the highest concentrations of PM₁₀ as a target site. Urine samples were collected from the 400 participants and analyzed for VOCs metabolites - trans,trans-Muconic Acid (t,t-MA) and N-AcetylS-(benzyl)-L-cysteine (BMA). Interviews were conducted by trained investigators to examine demographic information. The levels of t,t-MA and BMA were compared with representative South Korean population data (Korean National Environmental Health Survey). The association of the VOC metabolites and fine dust were analyzed by general linear regression analysis. Results: The mean of PM₁₀ in the target site was 42.50 ㎍/m³ from 2018 to 2020. Among the 400 participants in the target site, 74.8% were female and the average age of the participants was 66 years. The geometric mean of t,t-MA was 71.15 ㎍/g creatinine and the BMA was 7.00 ㎍/g creatinine among the residents. The levels were higher than the geometric mean from the 4th KoNEHS. The levels of t,t-MA showed significance in BMI, smoking status, and household income. BMA showed significance in gender and age. Conclusions: Compared to the general population of South Korea, the target site's residents had higher biomonitoring levels. Based on this study, continuous screening for high risk areas, including the target site, and biomonitoring of the residents are required.

• 한국환경농학회지
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• 제29권4호
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• pp.348-353
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• 2010

본 연구에서는 돈분 슬러리의 저장형태 및 온도에 따른 유기물의 거동을 관찰하였는데, closed system과 open system의 저장형태에 따른 유기물 농도는 $20^{\circ}C$에서 30일 저장 후 약 2배 정도의 차이를 보였다. 또한 온도에 의한 유기물 농도의 거동은 온도가 증가할수록 TS 및 VS 농도가 감소하였고, $20^{\circ}C$ 약 23%, $35^{\circ}C$ 약 29% 정도가 감소되는 것으로 나타났다. 하절기 외부온도 특성을 반영한 온도조건(20, $35^{\circ}C$) 및 저장기간 따른 생성된 유기산 종류는 비슷하였고, 저장기간 15일 이후부터 분변내 포함된 가수분해 및 산생성 미생물의 성장이 증대되어 유기산의 생성이 증가하였다. 반응시간 30일 후 생성된 총유기산 농도는 $20^{\circ}C$에서 $2,829\;mg{\cdot}COD/L$이었으며, $30^{\circ}C$에서는 $9,123\;mg{\cdot}COD/L^{\circ}C$로 초기 유기물농도 대비 각각 5.4, 17.4%의 유기산 전환율을 나타내었다. 따라서 돈분슬러리의 저장기간이 길어질수록 외부온도에 따라 가수분해 및 산생성 반응으로 유기산이 생성되고, 메탄생성균의 기질이용으로 유기물의 손실이 발생하여 온실가스 배출도 증가할 것으로 예상된다.

• 한국콘텐츠학회논문지
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• 제16권2호
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• pp.143-151
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• 2016

사람들이 집, 회사 등에서의 실내생활이 증가함에 따라 실내 공기오염에 대한 관심도가 높다. 본 논문에서는 실내 공기오염 중 인체에 가장 영향을 많이 미치는 이산화탄소, 미세먼지, 생활용품에서 발생되는 휘발성유기화합물(VOCs)를 측정할 수 있는 실내 공기오염 측정 시스템을 제안한다. 제안된 시스템은 실내 공기오염을 측정하는 디바이스, 정보를 저장하고 전송 할 수 있는 웹서버, 오염정보를 확인할 수 있는 안드로이드 어플리케이션으로 구성되어 있다. 본 시스템의 성능 확인을 위하여 초와, 담배연기 두 가지 시료의 실험을 통해 실내 공기 상태 변화를 어플리케이션으로 확인하였다. 또한, 외부 대기 상태와 디바이스로부터 측정된 내부 대기 상태를 비교할 수 있도록 시각화함으로써 사용자의 편의성을 증대시킬 수 있을 것으로 판단된다.

• Ocean and Polar Research
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• 제26권1호
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• pp.102-111
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• 2004

Recirculating aquaculture system (RAS) consists of different treatment compartments that maintain water quality within the ranges commonly recommended for fish cultures. However, common RASs still exert considerable environmental impact since concentrations of organic matter and nutrients in their effluents are high. Compared with the traditional RAS, the model RAS developed here use a sedimentation basin for digestion purposes and then use the released volatile organic matter to stimulate a denitrification process. Different treatment compartments for solids, total ammonia nitrogen, and nitrate removal have been reviewed. This paper provides the basic information on designing different treatment compartments as well as the engineering criteria in closed seawater RAS, consisting of circular tanks for fish cultures; dual drain systems, sedimentation basins and foam fractionators for removal of solids; nitrification biofilters for TAN removal; denitrification biofilters for nitrate removal; and aerators for aeration. The main purpose is to outline a common procedure in designing of closed RAS for marine fish culture with an emphasis on easy management and low expense, as well as reduction of the environmental impact.