• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.508-517
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• 2020

This study aimed to determine the minimum period of aeration treatment of co-digestate to develop it as liquid fertilizer and the chemical changes that occur in the aerobic liquefying process. The co-digestates were divided into three types depending on their additives: swine slurry anaerobic digestate (SS AD), swine slurry 70% + cow slurry 30% anaerobic digestate (SS + CS AD), and swine slurry 70% + apple pomace 30% anaerobic digestate (SS + AP AD). The pH of all co-digestates increased rapidly after 3 days of aerobic treatment, but had slightly decreased in SS AD after 9 days and in SS + CS AD and SS + AP AD after 15 days. All co-digestates showed a strongly reduced pH between 27 and 36 days of aeration treatment. SS AD had lower pH value, dissolved oxygen (DO), NH₄-N, and NO₃-N content under aerobic conditions than other co-digestates. To assess the fully decomposed liquid fertilizer, a germination test was performed on the undiluted and diluted co-digestate using the liquid fertilizer germination index (LFGI) method. The relative germination ratio, relative root elongation, and germination index of SS AD were higher than those of the others. When the LFGI method was used for the germination test, all co-digestates showed an appropriate germination index of 70 after 60 days of aeration treatment. Thus, we suggest that the minimum period of aeration treatment for co-digestates might be 60 days to develop the fully decomposed liquid fertilizer.

• Fire Science and Engineering
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• v.16 no.3
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• pp.77-83
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• 2002

We measured flame extinguishing concentration and flue gas composition in the n-heptane fuel cup-burner system using inert gas agents such as nitrogen, argon, carbon dioxide and their mixtures. The flame extinguishing concentration of binary gaseous mixture was well predicted by model which contains the flame extinguishing concentration and composition of pure components. The higher average specific gravity of the mixed inert gas agents, the more excellent flame extinguishing performance. And the structure of enclosed space also affects the fire extinguishing. The composition of carbon dioxide in the flue gas was decreased with increasing extinguishing agent used. Nitrogen monoxide production is not related with increasing nitrogen, but increased at rapid mass flow rate of air in the cup-burner.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.5
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• pp.63-68
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• 2009

This study describes to analyze foam mixing characteristics in steady state to enhance the performance of proportioner for foam system designed to accurately proportion a foam liquid concentrate into a water stream up to constant concentration. The proportioner developed is experimentally evaluated in performance evaluation system consisted of a pump, tanks, pressure gauges, flow meters, a nozzle. As a result, the foam mixing performance of the line proportioner is found to increase with increased the water flow rate due to the venturi effect and with increased the cross-sectional area of the orifice and is analysed with 3 % in the error rate of $\pm4%$. For the pressure proportioner, the foam mixing performance is analyzed to increase with increased the water flow rate and with increased the inlet pressure and is analysed with 3% in the error rate of $\pm2%$.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.351-354
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• 2006

본 연구에서는 산발효산물과 하수슬러지의 혼합소화를 위한 적정 혼합비를 도출을 위하여 음식물찌꺼기 고온 산발효산물과 하수슬러지의 생분해 특성과 적정혼합비를 도출하고자 수행한 결과 음식물찌꺼기 고온 산발효액과 하수슬러지를 혼합비별로 회분식 혼합소화 실험을 실시 한 결과 혼합비 1:1에서 385ml CH$_4$/g VS$_{added}$로 가장 높은 메탄발생량을 나타내었다. 이러한 결과는 음식물찌꺼기와 하수슬러지를 1:1로 동일하게 혼합하여 비교 소화실험을 실시했을 때 의 293m1 CH$_4$/g VS$_{added}$와 비교하여 상대적으로 높은 메 탄발생량을 나타내었다.

• Fire Science and Engineering
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• v.23 no.2
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• pp.78-84
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• 2009

We carried out fire extinguishing experiments with three kinds of water mist nozzle system. Fire extinguishing experiment according to installed nozzle height and fuel pan location was done. And fire extinguishing performance was compared with plain water and foam agent mixed solution. Water mist nozzle height was varied with 4m, 3.5m and 3m and position of fuel fan was varied 0.5m and 1m from the center of water mist nozzle. Foam agent that used in this experiment is 3% type of AFFF (Aqueous Film Forming Foam) solution. Experimental result showed the door opening effect was little. Fire extinguishing performance of foam agent mixture water mist was better than the plain water mist only.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.2
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• pp.5-13
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• 2020

This study was conducted to evaluate the effect of optimal aeration time of livestock manure slurry with fruits pomace on germination index. Six co-digestates of livestock manure slurry with fruits was aerated with 0.1 ㎥ air/㎥·min for 54 days. The maturity of digestates was evaluated using the germination method. The germination index(GI) of co-digestate of SS + CS + MP was more than 70 at the 30th day of aeration. The GI of co-digestate of SS + CS was more than 70 at the 36th day of aeration. The GI of digestate of swine manure slurry alone was 70 at the 54th day of aeration. The co-digestate of SS + MP caused to shorten 24 days of aeration period to reach GI of 70, compared to swine manure digestate. These results suggest that the germination index of seed could be used to establish the optimal aeration time for co-digestate of liquid fertilizer.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.23-24
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• 2013

침윤소화약제는 소화용수와 혼합시 표면장력을 저하시켜 침투성을 향상시키는 약제로 다공성 적층물질의 화재를 진압하기 위하여 사용된다. 목조건물 및 다공성물질, 적층물질에서 화재가 발생한 경우, 일반소화용수로는 재발화의 가능성이 있는 물질의 심부까지 침투하기 어려워 심부화재로 전이될 가능성이 높다. 따라서 소화용수에 침윤소화약제를 혼합함으로써 침투성능을 향상시켜 연소물질 심부의 화재를 진압하며 이에 대한 기준 연구가 절실히 요구되고 있는 현시점에서 침윤소화약제의 성능을 평가할 수 있는 기법의 필요성 또한 커지고 있다. 이에 본 연구에서는 분석학적 기법을 통하여 침윤소화약제의 성분에 대하여 제품별 공통 성분과 제품별 특성성분 데이터를 지문영역으로 확보하였다. 이러한 일치성 평가를 실시함으로써 인증을 득한 소화약제의 사후 관리 기법으로 활용하고자 기초연구를 실시하였다.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.2
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• pp.71-75
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• 2010

Production of crude glycerol from biodiesel industry is expected to exceed the commercial demand for purified glycerol in the near future. This study aimed to evaluate the feasibility of co-digestion of crude glycerol with swine manure. Crude glycerol up to 13.8 g/L was regarded as a good co-substrate for swine manure digester. It improved methane production and productivity by 90% and 120%, respectively. Methane yield of crude glycerol at the condition was estimated to be 232 mL/g. However, it inhibited methanogenic activity at above 27.5 g/L. Optimum concentration of crude glycerol for co-digestion with swine manure would be near to 13.8 g/L.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.10a
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• pp.217-225
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• 2003

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.66-73
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• 2009

Temperature phase anaerobic co-digestion process was conducted with the one to one mixture of food wastewater with livestock wastewater, and the presence and the dynamics of various pathogenic microorganisms was analyzed. The mixture contained various enteric and pathogenic bacteria, such as Escherichia coli. Enterobacteriaceae, Coliform bacteria. Staphylococcus aureus, Salmonella, Shigella, Listeria, and Yeast. Anaerobic digestion has become stabilized around 21 days after the reaction started, showing about 80% to 90% of remarkable reduction rates of microorganisms until this period in acidogenic reactor (AR) and methanogenic reactor (MR), respect ively. After stabilization, the average reduction rate of organic matter was recorded as around 60% in MR. Most microorganisms in the effluent were not detected at around the last period of the reaction, except Listeria and S. aureus, which showed the growth even at the last day of the reaction.