• 한국가시화정보학회지
• /
• 제9권1호
• /
• pp.36-41
• /
• 2011

It is highly needed to measure the dissolved oxygen (DO) concentration field in water for a variety of purposes such as biological, industrial, environmental monitoring and medical application. Application of PSP (Pressure Sensitive Paint) which is sensitive to oxygen concentration has been carried out to measure DO concentration field using PtOEP/PS film and intensity based method under the UV-LEDs illumination. A micro round water jet having 100% of DO was obliquely impinged on to a PtOEP/PS film coated plate placed in a 0% of DO water container. DO concentration fields on the impinging plate were quantitatively visualized with a $2.94\;{\mu}m$ of spatial resolution. Through pixel-by-pixel calibration, uncertainty of each pixel by different sensitivity, different dye concentration and non-uniformity of illumination was removed. It is demonstrated that the high DO concentration region was coincided with the impingement area. The DO concentration gradient due to DO diffusion was affected by Reynolds number.

• 한국수산과학회지
• /
• 제44권6호
• /
• pp.747-752
• /
• 2011

The parrotfish Oplegnathus fasciatus is a sub-tropical species that is difficult to culture during the winter in South Korea. As a result, a recirculating aquaculture system (RAS) was developed to rear parrotfish. This study investigated the effects of stocking density and dissolved oxygen (DO) concentration on the growth and hematology of the parrotfish in the RAS. The experimental stocking densities were 5 (SD05), 10 (SD10), 15 (SD15), and 20 kg/m3 (SD20) total body weight to tank water volume. As the stocking density increased, the mean weight gain, feed efficiency, and specific growth rate tended to decrease. However, SD10 and SD15 did not differ statistically from SD05 in feed efficiency (P>0.05). Although better growth was achieved in SD05, SD10 and SD15 appeared to be acceptable, practically and economically, in terms of feed efficiency. The experimental DO concentration ranges were 3-4 (DO3), 5-6 (DO5), and 7-8 mg/L (DO7). The mean weight gain and survival tended to increase with the DO concentration, but there were no differences among treatments (P>0.05). Although the feed efficiency did not differ among the treatments, the specific growth rates and daily feed intake increased with the DO concentration and were the highest in DO7 (P<0.05). The cortisol concentration was the highest in DO3 (P<0.05), while there was no difference between DO5 and DO7 (P>0.05).

• 한국해안·해양공학회논문집
• /
• 제33권6호
• /
• pp.238-245
• /
• 2021

본 연구에서는 LSTM 모델을 활용하여 낙동강 하구역의 DO 농도 예측을 위한 최적 모델 조건과 적합한 예측변수를 찾기 위한 Case study를 수행하였다. 모델 매개변수 case study 결과, Epoch = 300과 Sequence length = 1에서 상대적으로 높은 정확도를 보였다. 예측변수 case study 결과, DO와 수온을 예측변수로 했을 때 가장 높은 정확도를 보였으며, 이는 DO 농도와 수온의 높은 상관성에 기인한 것으로 판단된다. 상기 결과로부터 낙동강 하구역의 DO 농도 예측에 적합한 LSTM 모델 조건과 예측변수를 찾을 수 있었다.

• 한국해안해양공학회지
• /
• 제14권4호
• /
• pp.295-307
• /
• 2002

진해ㆍ마산만에서 수온, 염도 및 DO농도를 연직방향으로 1년동안 측정하였다. 관측된 수온 및 염도 자료를 이용하여 성층화 특성을 분석하고, DO농도의 연직변화를 성층화 특성 및 저질오염도와 관련하여 분석하였다. 분석결과, 진해ㆍ마산만의 수온 성층화는 4월 이전에 시작되어 10월경에 종료되는 양상을 보이고 있는 것으로 판단되었다. 또한, 1998년 4월 연직방향의 평균 염도변화는 3.9(equation omitted) 정도로 증가되고, 1998년 8월 9.3(equation omited), 10월 4.3(equation omitted) 정도가 유지되어 가을철에도 염도 성층이지속되고 있는 것으로 파악되었다. 한편, DO 농도는 성층화가 시작되는 4월을 기점으로 연직방향 평균 DO농도변화도 2.6(mg/L)에서 6월 8.3(mg/L), 8월 5.9(mg/L), 9월 7.24(mg/L), 10월4.4(mg/L)으로 명확한 성층화 양상을 보이고 있다. DO 농도변화는 전체적으로 해역의 오염도와 밀접한 관련이 있으나. 성층화 기간동안 연직방향 DO 농도편차가 크게 나타나고 있는것은 수온 및 염도성층에 의한 표 저층간의 물질교환 저해에 의한 영향도 직접적인 요인으로 작용하고 있은 것으로 파악되었다.

• Asian Journal of Atmospheric Environment
• /
• 제7권2호
• /
• pp.85-94
• /
• 2013

Methane concentrations have been monitored at the Anmyeon-do Observatory, Korea, since 1999. In recent years, the methane concentration has increased, but the sources of this increase have yet to be identified. This study was designed to identify the major source contributing to the increase by using World Data Centre for Greenhouse Gases (WDCGG) data and the Greenhouse Gases Emission Presumption (GEP) method. The data were collected at Anmyeon-do between 2003 and 2009 (except 2008), and the analyses showed that the increase in methane concentration originated mainly in rice paddies around the observation point. The annual average methane concentration at Anmyeon-do was 1894 ppb, of which 100-103 ppb (5.3-5.4%) was shown to originate mainly from rice paddies. The seasonal fluctuation in methane concentration from May to October estimated by the GEP method was compared with experimental data of previous research conducted on rice paddies. The close match obtained through this comparison shows that the GEP method is effective. The difference in methane concentration was also analyzed in terms of land use and land cover. It was shown that although rice paddies account for only 14.7% of the area surveyed, they accounted for between 69 and 90% of the total increase in methane concentration. These results confirm that rice paddies are the main source of the increase in methane concentration observed at Anmyeon-do.

• 한국해안해양공학회지
• /
• 제19권4호
• /
• pp.385-398
• /
• 2007

주문진항에서 2002년부터 2005년까지 월별로 관측한 일반 수질항목의 정점별, 계절별 변화 양상을 분석하였다. 분석항목은 수온, 염도, pH, SS, DO 항목이다. 일반수질항목의 상층·하층 변화는 뚜렷한 차이를 보이지 않는 것으로 파악되었다. 반면, 계절별 농도변화는 수온 및 DO 농도는 뚜렷한 변화양상을 보였으나, SS 항목 등은 불규칙한 양상을 보이고 있는 것으로 파악되었다. 또한, 지점별, 월별 자료를 영역별, 연도별로 평균하여 해수교환시설 및 하수종말처리시설의 수질개선효과를 정량적으로 분석하였다. 분석 결과, SS농도변화는 하수종말 처리시설 가동에 의한 영향이 매우 미미하게 반영되었으며, 해수교환시설에 의한 영향은 영역 1, 2 각각 26%, 16% 정도의 명확한 농도저감효과를 보이고 있는 것으로 파악되었다. 한편, DO 농도는 하수종말 처리시설 가동 후, 주문진항 내부영역에서 10% 내외로 농도가 저하되는 효과를 보였으나, 해수교환시설 건설 후에는 오히려 10% 내외 증가되는 양상을 보이고, 2005년도 DO 농도는 2002년도에 비하여 변화가 없는 것으로 파악되어 10% 내외의 DO 농도변화는 하수처리장 및 해수순환시설 설치효과로 파악하는 것보다는 자연적인 연변화 범위로 판단하는 것이 적절할 것으로 사료된다.

• 환경위생공학
• /
• 제17권2호
• /
• pp.63-70
• /
• 2002

We investigated the concentration degree of VOCs for ambient air in the air environment control area of Kyonggi-do in 2001. The VOCs showing higher concentration were in the ascending order of Toluene > n-Butane > 1-Butene > Benzene > n-Hexane. The concentration distribution ratio mentioned above showed almost same pattern in each city. The relative concentration ratio of Benzene, Toluene, Ethylbenzene, Xylenes which are aromatic VOCs were 1 : 6.3 : 0.6 : 1.6. It was similar to the pattern in 1999 but different from the pattern in 2000. In the aspect of seasons, the highest B.T.E.X concentration was indicated in fall and in the aspect of areas, the higher concentration showed in the ascending order of Buchon > Ansan > Kwangmyong > Shihung > Sungnam. The average concentration of target VOCs for ambient air in the air environment control area of Kyonggi-do showed lower concentration than the metropolis of Seoul but higher concentration than Kwang-ju city and Dae-gu city. The amount of total VOCs was increasing, comparing with it last year and the more increasing tendency is anticipated so that it will need to establish the proper regulative criteria.

• 한국유기농업학회지
• /
• 제19권spc호
• /
• pp.131-134
• /
• 2011

• 한국환경보건학회지
• /
• 제9권1호
• /
• pp.1-13
• /
• 1983

This study was carried out to investigate nitrification in the main stream of the Naktong river for two times, 12-13 August and 23-26 September 1982. The results of this study were as follows : 1. The increase of nitrogen concentration was due to inflow of Geumho river, which was polluted by the municipal and industrial wastewater of Daegu city. 2. The rate constant of ammonia calculated for three reaches was high according to the stream flow and was eminently low in the reach from Goroung to Gangjung. (0.068-0.116 $day^{-1}$). This phenomena might be attributed to the sublethal or even lethal effect upon aquatic life by relatively low DO concentration and high heavy metal concentration. 3. DO consumption rate by nitrification was highest for the reach from Goroung to Daeam where was affected by Geumho river. (56.7-147.8%). This phenomena might be attributed to low DO concentration and high nitrogen concentration. Especially, the less stream flow was, the higher DO consumption was. And so, nitrification in the station where is low DO concentration, especially under the low flow condition, might cause more serious water quality management problem. Therefore, for the purpose of effective conservation of water quality in the Naktong river, it was suggested that We have more concern about the nitrogen compound, and more study on the nitrification phenomena.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2002년도 생물공학의 동향 (X)
• /
• pp.355-358
• /
• 2002

본 연구는 제약폐수 처리에 있어서 폐수처리장내의 미생물 활성을 최대로 하여 운전효율을 높이는 것을 목적으로 한다. 생물 반응기내의 미생물의 활성과 최적 용존산소 농도에는 어떤 상관관계가 있는가를 규명하기위해 연속식 실험을 진행한 결과, 0${\sim}$1.0 ppm 정도의 낮은 DO농도에서는 COD의 감소율도 적고, 1.5${\sim}$3.0 ppm 정도일 때에는 COD의 감소율이 다른 DO농도일 때 보다 상대적으로 높았다. 그러나 3.0 ppm 이상의 DO농도에서는 오히려 COD 감소율이 작아진다.