• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
• /
• pp.777-783
• /
• 2000

Composting by negative aeration is a reasonable proposition to control odor generated during composting process. Cattle manure and rice hulls mixtures were composted in a bin composting system by negative aeration. Continuous(CA) and intermittent(IA) aeration methods were applied to analyze the composting characteristics. The composting temperature and the ammonia emission during composting were investigated according to the aeration methods. The main problem for the negative aeration was the generation of condensate in the suction line of blower. The quantity of condensate was significant for continuous aeration. The aeration method should be modified to escape from the cooling effect of continuous aeration at the initial stage of composting. It took a longer time to finish a composting for intermittent aeration on account of lower aeration. It was concluded that the composting by negative aeration could be accomplished by either continuous or intermittent aeration method if the flow rate would be controlled more efficiently and the water vapor in suction line of blower could be removed effectively. Ammonia emission increased up to maximum value of 675ppm for continuous aeration while 300ppm for intermittent aeration. However, the cumulative value of ammonia emission was larger for intermittent aeration than for continuous aeration.

• 한국환경과학회지
• /
• 제13권7호
• /
• pp.675-680
• /
• 2004

This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P, and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).

• 한국식품과학회지
• /
• 제51권6호
• /
• pp.576-583
• /
• 2019

본 연구에서는 aeration 공정을 거친 홍삼 추출액의 유효성분 함량을 확인하고 항산화 활성에 미치는 영향을 알아보고자 하였다. Aeration 처리 유무에 따른 추출액의 색상 변화에서는 aeration 공정처리를 하지 않은 추출액과 aeration 공정처리 한 추출액 모두 추출시간이 경과함에 따라서 L값과 b값이 유의적으로 감소하였고, aeration 공정 처리 36시간 추출액에서 명도와 황색도가 가장 낮은 결과를 얻었다. a값은 non-aeration 처리에서는 추출시간이 경과함에 따라서 증가하였으나 aeration 처리할 경우에는 적색도가 감소되는 것을 확인할 수 있었다. 이와 같은 결과는 aeration 공정 처리를 할 경우에는 추출시간이 경과함에 따라 명도, 황색도, 적색도 모두가 감소되면서 갈색도가 증가하는 것을 의미하는 결과라고 할 수 있다. 총 폴리페놀 함량에서 non-aeration 홍삼추출액은 추출시간에 따라 0.62, 0.67, 0.72, 0.79 mg GAE/mL로 나타났으며 aeration 공정을 거친 추출액은 0.62, 0.70, 0.84, 0.96 mg GAE/mL로 추출시간에 따라 유의적으로 크게 증가하는 것을 확인하였다. 또한, 총 플라보노이드 함량은 aeration 공정을 거친 24, 36시간 추출액에서 21.77, 21.93 mg GAE/mL의 최고의 함량을 나타내었다. DPPH 라디칼 소거활성은 non-aeration 홍삼 추출액은 80.50-82.00% 범위에서 확인되었으며 aeration 공정을 거친 홍삼 추출액의 라디칼 소거능은 추출 시간에 따라 82.10, 81.90, 87.30, 87.10%로 나타났다. 이는 DPPH 라디칼 소거활성이 aeration 공정을 거침에 따라 활성이 증가한다는 것을 시사하는 결과이다. ABTS 라디칼 소거능은 24, 36시간에서 non-aeration 추출액이 96.80, 77.60%로 라디칼 소거활성이 떨어졌으나 aeration 공정을 거친 홍삼 추출액은 70.86, 98.60%로 추출 시간에 따라 유의적으로 소거활성이 증가하는 것으로 나타났다. 또한 10, 12, 24, 36시간 동안 aeration 공정을 거친 홍삼 추출액은 65.40, 65.03, 65.61, 63.26%의 hydrogen peroxidase 소거율을 보였고, 또한 0.87, 0.99, 1.04, 0.99로 환원력이 유의적으로 증가하는 것을 확인하였다. 이러한 결과들은 DPPH, ABTS의 경향과 유사하게 aeration 공정을 거침으로서 non-aeration보다 항산화능이 우수하다는 것을 나타냈다. Aeration 공정을 처리한 홍삼추출액으로부터 얻어진 진세노사이드의 함량은 non-aeration과 비교 했을 때 Rg3에서 현저히 차이가 나며, 저분자 진세노사이드 Rg3의 함량이 aeration 공정을 처리한 홍삼추출액에서 166.55, 219.71, 526.67, 581.13 ㎍/mL로 non-aeration 보다 많은 양이 생성되는 것을 확인 할 수 있었다. 이러한 결과들은 aeration 공정을 거친 홍삼추출액이 전반적으로 우수한 항산화 활성을 나타내었으며 향후 특정유효성분을 강화시킬 수 있는 새로운 공정방법으로 활용될 수 있을 것이라 사료된다.

• 산업기술연구
• /
• 제23권A호
• /
• pp.193-197
• /
• 2003

This bench-scale research investigated the aeration cycle(on/off) as the controlling factors for nitrogen and phosphorus removal in a 2-stage, intermittent aeration process. At this experiment, the aeration cycle time(air-on/air-off) was 30min/30min, 60min/60min, 90min/90min. Organic matter removal was observed more than 90% regardless of the aeration cycle and phosphorus removal was relatively high when the aeration cycle time was 60min/60min On the other hand. For all of the aeration cycle, TN removal was appeared less than 55%. This result was probably due to the limitation of the external substrate for heterotrophic nitrification and aerobic denitrification.

• Tribology and Lubricants
• /
• 제17권6호
• /
• pp.447-452
• /
• 2001

In development process of engine lubrication system, many failure cases are related with aeration problem. Therefore, it is very important to clarify the aeration in the engine oil circuit system. As of today, many factors have been introduced as the major cause in the engine oil aeration. However, still many test data related with those are required to clearly understand it. In this paper the aeration measurement system and calculation method are introduced. And also using this system we measured engine oil aeration for various cases. From these results some conclusions are reduced.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
• /
• pp.171-176
• /
• 2000

In development process of engine lubrication system, many failure cases are related with aeration problem. Therefore, it is very important to clarify the aeration in the engine oil circuit system. As of today, many factors have been introduced as the major cause in the engine oil aeration. However, still many test data related with those are required to clearly understand it. In this paper the aeration measurement system and calculation method are introduced. And also using this system we measured engine oil aeration fur various cases. From these results some conclusions are reduced.

• Journal of Microbiology and Biotechnology
• /
• 제19권1호
• /
• pp.93-98
• /
• 2009

The thermophilic aerobic digestion (TAD) process is recognized as an effective method for rapid waste activated sludge (WAS) degradation and the deactivation of pathogenic microorganisms. Yet, high energy costs due to heating and aeration have limited the commercialization of economical TAD processes. Previous research on autothermal thermophilic aerobic digestion (ATAD) has already reduced the heating cost. However, only a few studies have focused on reducing the aeration cost. Therefore, this study applied a two-step aeration control strategy to a fill-and-draw mode semicontinuous TAD process. The NADH-dependent fluorescence was monitored throughout the TAD experiment, and the aeration rate shifted according to the fluorescence intensity. As a result, the simple two-step aeration control operation achieved a 20.3% reduction in the total aeration, while maintaining an effective and stable operation. It is also expected that more savings can be achieved with a further reduction of the lower aeration rate or multisegmentation of the aeration rate.

• 한국자동차공학회논문집
• /
• 제7권7호
• /
• pp.129-135
• /
• 1999

We developed a new measuring equipment which makes it possible to perform on-line measurements with the merits of its implicity and the time-saving characteristics. By using the newly developed measurement system, the amount of aeration is directly measured on several parameters, i.e, engine speed, oil quantity, oil deterioration, oil temperature and viscosity, etc. It showed that oil aeration is strongly related to be gas movements in crankcase and the residence time of circulating oil in oil pan. In addition, in order to clarify the mechanism of aeration and to quantify the degree of aeration, a modelling analysis to predict aeration was performed , and as a guiding parameter, Aeration Index was defined. Finally, the parameter was compared with the actual amount of aeration, and it was confirmed that they gave a good correlation with each other.

• KSBB Journal
• /
• 제27권4호
• /
• pp.263-267
• /
• 2012

The purpose of this study was to determine optimum value of aeration rate for the cultivation of Chlorella sp. under illumination of red light emitting diode. The aeration rates varied from 0 to 2.4 vvm under the illumination of 4,400 lux of red light emitting diode. The highest specific growth rate of $1.51\;day^{-1}$ was obtained at the aeration of 0.7 vvm and lower specific growth rates were obtained for other aeration tests. Furthermore, the highest biomass concentration (1.02 g/L) was also obtained at the aeration of 0.7 vvm. Therefore, aeration of 0.7 vvm was determined to be the optimum aeration rate for the cultivation of Chlorella sp. under red light emitting diode.

• 한국환경보건학회지
• /
• 제35권2호
• /
• pp.116-123
• /
• 2009

Laboratory scale experiments were conducted to investigate the removal characteristics of nitrogen and phosphorus by the variation of aeration time in four sequencing batch reactors (SBRs). In R1 which has the shortest aeration time as 1 h, MLVSS concentration in reactor decreased by the wash-out of biomass because of the poor sedimentation. The TOC removal efficiencies were almost similar in 3 reactors except R1. At the low aeration time as 1 h, the nitrification was severely inhibited by the deficiency of oxygen. ${NH_4}^+$-N removal efficiency was decreased by the decrease of aeration time. At the aeration time over 2 h, the phosphorus removal efficiency was not affected by the variation of aeration time. The nitrification was inhibited but the phosphorus release and uptake was not inhibited by the decrease of low aeration time. Therefore, we can see that the phosphorus removal microorganisms are superior to nitrification microorganisms in oxygen utilization.