• 제목/요약/키워드: Input concentration

검색결과 676건 처리시간 0.029초

방전Plasma 반응에 의한 NOx의 안전처리에 관한 연구 (A Study on Safety Treatment of NOx by Discharge Plasma Reaction)

  • 최재욱;야마구마 미즈키
    • 한국안전학회지
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    • 제15권2호
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    • pp.92-96
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    • 2000
  • In this experiment, we studied about concentration characteristics of $NO_x$ and generation of ozone in the reactor of corona discharge type by using mixed gas of $NO/N_2$ and $N_2/O_2$. In the case of the initial NO concentration increased, decrease rate of NO concentration was weakened and discharge input power of minimum NO concentration became high. When NO concentration was high, NO decomposition limit was appeared. And NO reduction rate was decreased, when initial NO concentration and discharge input power increased. When discharge input power was 5W, we could know the most proper energy value for treatment of NO. When the concentration of initial NO increased, generation of ozone decreased and in the case of same concentration of NO, according to discharge input power increase, generation of ozone increased.

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신경망의 계층 연관성 전파를 이용한 DNN 예보모델의 입력인자 분석 (Analysis of Input Factors of DNN Forecasting Model Using Layer-wise Relevance Propagation of Neural Network)

  • 유숙현
    • 한국멀티미디어학회논문지
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    • 제24권8호
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    • pp.1122-1137
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    • 2021
  • PM2.5 concentration in Seoul could be predicted by deep neural network model. In this paper, the contribution of input factors to the model's prediction results is analyzed using the LRP(Layer-wise Relevance Propagation) technique. LRP analysis is performed by dividing the input data by time and PM concentration, respectively. As a result of the analysis by time, the contribution of the measurement factors is high in the forecast for the day, and those of the forecast factors are high in the forecast for the tomorrow and the day after tomorrow. In the case of the PM concentration analysis, the contribution of the weather factors is high in the low-concentration pattern, and that of the air quality factors is high in the high-concentration pattern. In addition, the date and the temperature factors contribute significantly regardless of time and concentration.

산업 발생 노르말헥산과 벤젠 증기의 저온 분해 (Low-Temperature Thermal Decomposition of Industrial N-Hexane and Benzene Vapors)

  • 조완근;이준엽;강정환;신승호;권기동;김모근
    • 한국환경과학회지
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    • 제15권7호
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    • pp.635-642
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    • 2006
  • Present study evaluated the low-temperature destruction of n-hexane and benzene using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst. The parameters tested for the evaluation of catalytic destruction efficiencies of the two volatile organic compounds(VOC) included input concentration, reaction time, reaction temperature, and surface area of catalyst. It was found that the input concentration affected the destruction efficiencies of n-hexane and benzene, but that this input-concentration effect depended upon VOC type. The destruction efficiencies increased as the reaction time increased, but they were similar between two reaction times for benzene(50 and 60 sec), thereby suggesting that high temperatures are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Similar to the effects of the input concentration on destruction efficiency of VOCs, the reaction temperature influenced the destruction efficiencies of n-hexane and benzene, but this temperature effect depended upon VOC type. As expected, the destruction efficiencies of n-hexane increased as the surface area of catalyst, but for benzene, the increase rate was not significant, thereby suggesting that similar to the effects of the re- action temperature on destruction efficiency of VOCs, high catalyst surface areas are not always proper for economical thermal destruction of VOCs. Depending upon the inlet concentrations and reaction temperatures, almost 100% of both n-hexane and benzene could be destructed, The current results also suggested that when applying the mesh type transition Metal Pt/SS catalyst for the better catalytic pyrolysis of VOC, VOC type should be considered, along with reaction temperature, surface area of catalyst, reaction time and input concentration.

기질 농도에 따른 미생물전기분해전지의 운전 특성 (Effect of substrate concentration on the operating characteristics of microbial electrolysis cells)

  • 서휘진;김재일;기서진;안용태
    • 유기물자원화
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    • 제31권4호
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    • pp.41-49
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    • 2023
  • 본 연구는 주입 기질 농도에 따른 미생물전기분해전지 (Microbial electrolysis cell, MEC)의 운전성능을 조사하였다. 주입 기질 농도에 따른 MEC의 운전 성능을 비교하기 위해 6 개의 실험실 규모 MEC를 2, 4, 6 g/L Sodium acetate 조건으로 순서대로 주입 농도를 증가시켜 운전하였다. 전류밀도, 수소 생산량, SCOD 제거율을 분석하였고, 에너지 효율, cathodic hydrogen recovery를 계산하여 주입 기질 농도 별 MEC의 운전성능을 비교하였다. 체적 전류밀도는 4 g/L 조건에서 76.3 A/m3였고, 6 g/L로 주입 농도를 증가시켰을 때 19.0 A/m3로 4 g/L 주입 조건에 비해 75% 감소하였다. 수소 생산량은 4 g/L 주입 조건이 47.3 ± 16.8 mL로 가장 높았으나 수소 수율은 2 g/L 주입 조건이 1.1 L H2/g CODin로 가장 높았다. 에너지 효율 역시 2 g/L 조건에서 가장 높았고, 6 g/L 조건에서 가장 낮은 결과를 보여주었다. 최대 전기에너지 효율은 76.4%였으며, 2 g/L 조건에서 최대 전체에너지 효율은 39.7%였다. 그러나 기질 농도가 6 g/L로 증가하였을 때, 성능이 급격히 감소하였다. Cathodic hydrogen recovery 역시 에너지 효율과 유사한 경향을 보였으며, 가장 낮은 농도 조건에서 가장 높은 성능을 보여주었다. 따라서 MEC 운전에 있어서 SCOD 제거율뿐만 아니라 에너지 효율 등을 고려한 최적 운전을 위해서는 낮은 주입 농도 조건에서 운전하는 것이 바람직할 것으로 판단된다.

移動汚染源에 대한 大氣擴散模型의 感應度 分析에 관한 硏究 (HIWAY2, PAL, CALINE3 模型을 對象으로) (A Study on the Sensitivity Analysis of Line Source Air Quality Models)

  • 김선태;김병태;김정욱
    • 한국대기환경학회지
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    • 제5권1호
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    • pp.1-10
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    • 1989
  • The sensitivity analysis is a method to quantify to what extent the output of a model changes with the values of input parameters. This will lead to increase model accuracy through measurement validation. Three line source air quality models, HIWAY 2, PAL, and CALINE 3 were selected for this study. The input parameters analysed included wind speed, wind direction, stability, emission rate, mixing height, receptor distance, initial dispersion coefficient, surface roughness, and averaging time. It turned out that PAL model generally showed higher concentration than other two models, and that between CALINE 3 and HIWAY 2, CALINE 3 showed higher concentration than HIWAY 2 model near the line sources, but beyond a certain downwind distances HIWAY 2 model showed higher concentration. The modesl were very sensitive to wind speed especially in the range of 0 $\sim$ 1 m/s and to wind direction near the parallel wind to streets. In case of emission rate, the output concentration was directly proportional to these input parameters. And the sensitivity of the input parameters such as stability, mixing height, initial dispersion coefficient, surface roughness, and averaging time were not very significant.

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수소생산 고정화 생물반응기의 특성(III) -루프 반응기에서의 수소 생산- (Characteristics of the Bioreactors of Hydrogen-producing Immobilized Cells (III) -Hydrogen Production in a Nozzle Loop Reactor-)

  • 이충곤;선용호;한정우;이현순;조영일
    • 한국미생물·생명공학회지
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    • 제17권6호
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    • pp.629-633
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    • 1989
  • In the continuous reactor, the hydrogen production rate and residual glucose concentration were increased with increase of input glucose concentration, dilution rate, and recycle rate. The maximum production rate was 91 mL/Lㆍh at dilution rate 0.4/h, input glucose concentration 5.4g/L, and recycle rate 70/h in this experimental range.

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광합성 박테리아를 이용한 고성능 수소 생산 고정화 생물반응기의 개발(I) 고정화 연속 교반탱크 반응기에서의 수소 생산성 및 효율인자 평가 (Development of Bioreactors for Hydrogen-Producing Immobilized Photosynthetic Bacteria(I) : Evaluation of lmmobilized CSTR for Hydrogen Productivity and Effectiveness Factor)

  • 선용호;한정우
    • KSBB Journal
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    • 제8권3호
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    • pp.243-255
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    • 1993
  • In this study, it was observed that hydrogen Productivity varied with stirrer speed, bead radius, input glucose concentration and dilution rate in a continuous stirred tank reactor in which immobilized R. rubrum KS-301 was used as a hydrogen-producing bacterium The mass transfer resistance due to cell immobilization was also studied. In order to estimate an effectiveness factor, Des of glucose was first obtained, which was subsequently represented by the correlation equation between Dos and Xb, As a result external mass transfer resistance could be neglected for stirrer speeds greater than 400rpn With bead radius increasing, the hydrogen productivity and internal effectiveness factor decreased. With input 91ucose concentration increasing, the hydrogen productivity and interval and external effectiveness factor increased. Although an Internal effectiveness factor was not affected, hydrogen productivity Increased with dilution rate increasing. An overall effectiveness factor remained nearly constant for the dilution rates investigate4 but increased with input 91ucose concentration increasing.

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공기 중 메틸에틸케톤 제어를 위한 Pilot-Scale 흡수 시스템의 운영인자 분석 (Analysis of Operation Parameters of Pilot-Scale Packed-Absorption System for Airborne Methyl Ethyl Ketone Control)

  • 조완근;김왕태
    • 한국환경과학회지
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    • 제20권4호
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    • pp.501-509
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    • 2011
  • Unlike many laboratory-scale studies on absorption of organic compounds (VOCs), limited pilot-scale studies have been reported. Accordingly, the present study was carried out to examine operation parameters for the effective control of a hydrophilic VOC (methyl ethyl ketone, MEK) by applying a circular pilot-scale packed-absorption system (inside diameter 37 cm ${\times}$ height 167 cm). The absorption efficiencies of MEK were investigated for three major operation parameters: input concentration, water flow rate, and ratio of gas flow-rate to washing water amount (water-to-gas ratio). The experimental set-up comprised of the flow control system, generation system, recirculation system, packed-absorption system, and outlet system. For three MEK input concentrations (300, 350, and 750 ppm), absorption efficiencies approached near 95% and then, decreased gradually as the operation time increased, thereby suggesting a non-steady state condition. Under these conditions, higher absorption efficiencies were shown for lower input concentration conditions, which were consistent with those of laboratory-scale studies. However, a steady state condition occurred for two input concentration conditions (100 and 200 ppm), and the difference in absorption efficiencies between these two conditions were insignificant. As supported by an established gas-liquid absorption theory, a higher water flow rate exhibited a greater absorption efficiency. Moreover, as same with the laboratory-scale studies, the absorption efficiencies increased as water-to-gas ratios increased. Meanwhile, regardless of water flow rates or water-to-gas ratios, as the operation time of the absorption became longer, the pH of water increased, but the elevation extent was not substantial (maximum pH difference, 1.1).

Measuring the Effectiveness of an Ecosystem Service to Regulate Air Quality in Wetland, South Korea

  • Kim, Jung In;Lee, Kyungeun;Yeo, Inae;Choi, Tae-Young;Lee, Beom Hee;Jung, Pil Mo;Joo, Wooyeong
    • Proceedings of the National Institute of Ecology of the Republic of Korea
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    • 제2권1호
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    • pp.62-69
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    • 2021
  • This study aimed to verify the suitability of an air quality regulating service for wetland ecosystem service evaluation by investigating the effect of reducing particulate matter (PM) on vegetation in wetlands. We installed tunnel-type experimental plots at Yonghwasil Pond in the National Institute of Ecology and set up the input and output of PM by applying the natural vegetation of the relevant wetlands. We took measurements by replicating four different conditions four times each. The air quality regulating service in each experimental plot was measured based on PM10 concentration; further, the difference between the input and the output concentration of PM passing through the Phragmites australis community tunnel was measured using a light scattering method. For the Phragmites australis community in the outdoor conditions and bare land, the PM concentration was measured with the same specifications as tunnel-type experimental plots without setting up the input and output. For the tunnel-type experimental plots, PM10 concentration was significantly lower in the output than in the input. Furthermore, in the outdoor conditions, a comparison between the Phragmites australis community and bare land showed that the concentration was relatively low in the former than in the latter. This confirmed the PM reducing effect due to the blockage and absorption of PM depending on the growth of Phragmites australis. Based on the results of this study, we assessed the air quality regulating service in wetlands as an evaluation indicator.

계층 연관성 전파를 이용한 DNN PM2.5 예보모델의 입력인자 분석 및 성능개선 (Analysis of Input Factors and Performance Improvement of DNN PM2.5 Forecasting Model Using Layer-wise Relevance Propagation)

  • 유숙현
    • 한국멀티미디어학회논문지
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    • 제24권10호
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    • pp.1414-1424
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    • 2021
  • In this paper, the importance of input factors of a DNN (Deep Neural Network) PM2.5 forecasting model using LRP(Layer-wise Relevance Propagation) is analyzed, and forecasting performance is improved. Input factor importance analysis is performed by dividing the learning data into time and PM2.5 concentration. As a result, in the low concentration patterns, the importance of weather factors such as temperature, atmospheric pressure, and solar radiation is high, and in the high concentration patterns, the importance of air quality factors such as PM2.5, CO, and NO2 is high. As a result of analysis by time, the importance of the measurement factors is high in the case of the forecast for the day, and the importance of the forecast factors increases in the forecast for tomorrow and the day after tomorrow. In addition, date, temperature, humidity, and atmospheric pressure all show high importance regardless of time and concentration. Based on the importance of these factors, the LRP_DNN prediction model is developed. As a result, the ACC(accuracy) and POD(probability of detection) are improved by up to 5%, and the FAR(false alarm rate) is improved by up to 9% compared to the previous DNN model.