• Title/Summary/Keyword: Aerosol Model

Search Result 309, Processing Time 0.023 seconds

Detection of Wildfire Smoke Plumes Using GEMS Images and Machine Learning (GEMS 영상과 기계학습을 이용한 산불 연기 탐지)

  • Jeong, Yemin;Kim, Seoyeon;Kim, Seung-Yeon;Yu, Jeong-Ah;Lee, Dong-Won;Lee, Yangwon
    • Korean Journal of Remote Sensing
    • /
    • v.38 no.5_3
    • /
    • pp.967-977
    • /
    • 2022
  • The occurrence and intensity of wildfires are increasing with climate change. Emissions from forest fire smoke are recognized as one of the major causes affecting air quality and the greenhouse effect. The use of satellite product and machine learning is essential for detection of forest fire smoke. Until now, research on forest fire smoke detection has had difficulties due to difficulties in cloud identification and vague standards of boundaries. The purpose of this study is to detect forest fire smoke using Level 1 and Level 2 data of Geostationary Environment Monitoring Spectrometer (GEMS), a Korean environmental satellite sensor, and machine learning. In March 2022, the forest fire in Gangwon-do was selected as a case. Smoke pixel classification modeling was performed by producing wildfire smoke label images and inputting GEMS Level 1 and Level 2 data to the random forest model. In the trained model, the importance of input variables is Aerosol Optical Depth (AOD), 380 nm and 340 nm radiance difference, Ultra-Violet Aerosol Index (UVAI), Visible Aerosol Index (VisAI), Single Scattering Albedo (SSA), formaldehyde (HCHO), nitrogen dioxide (NO2), 380 nm radiance, and 340 nm radiance were shown in that order. In addition, in the estimation of the forest fire smoke probability (0 ≤ p ≤ 1) for 2,704 pixels, Mean Bias Error (MBE) is -0.002, Mean Absolute Error (MAE) is 0.026, Root Mean Square Error (RMSE) is 0.087, and Correlation Coefficient (CC) showed an accuracy of 0.981.

Inhibitory Effect of Aerosolized Commercial Sanitizers against Foodborne Pathogens (에어로졸 형태의 상업적 살균소독제의 병원성 미생물에 대한 저해효과 평가)

  • Lee, Sun-Young;Jung, Jin-Ho;Jin, Hyun-Ho;Kim, Young-Ho;Oh, Se-Wook
    • Journal of Food Hygiene and Safety
    • /
    • v.22 no.4
    • /
    • pp.235-242
    • /
    • 2007
  • This study was conducted to investigate the effect of aerosolized chemical sanitizers on inhibiting foodborne pathogens such as Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes. Five domestic commercial sanitizers subjected to five groups of sanitizer (chlorine-based, hydrogen peroxide-based, Iodophor-based, quaternary ammonium-based, and alcohol-based sanitizers) were aerosolized by an aerosol generator into a model cabinet and treated in laboratory media containing three pathogens for 1 h at room temperature. Aerosolized hydrogen peroxide-based and quaternary ammonium-based sanitizers were effective at inhibiting levels of E. coli O157:H7 (ca. 4-9 log reductions) whereas other aerosolized sanitizers such as chlorine-based, Iodophor-based, and alcohol-based sanitizers did not significantly reduced the levels of E. coli O157:H7. For S. typhimurium, the only aerosolized hydrogen peroxide-based sanitizer was effective and resulted in ca. 5-9 log reduction. Aerosolized hydrogen peroxide-based, Iodophor-based, and quaternary ammonium-based sanitizers significantly reduced levels of L. monocytogenes and especially, aerosolized quaternary ammonium-based sanitizer was strongly effective to kill L. monocytogenes, resulted in higher than 8.8 log reduction. And there was no special trend in inhibitory efficacy of sanitizers aerosolized by 1.6 or 2.4 MHz aerosol generators. From these results, aerosolization has great potential for use in commercial applications however it's efficacy could be very different depending on type of sanitizers.

Development of a Real-time Monitoring Device for Measuring Particulate Matter

  • Kim, Dae Seong;Cho, Young Kuk;Yoon, Young Hun
    • Particle and aerosol research
    • /
    • v.10 no.1
    • /
    • pp.1-8
    • /
    • 2014
  • In this study, we have developed a real-time monitoring device for measuring $PM_{10/2.5/1}$ of ambient aerosol particles. The real-time PM (Particulate Matter) monitor was based on the light scattering method and had 16 channels in particle size. The laboratory and field tests were carried out to evaluate the performance of the PM monitor developed. Arizona Road Dust particles ranging from diameter of 0.1 to $20{\mu}m$ were generated as test particles in the laboratory test. The field test was carried out at the Seoul Meteorological Observatory. We can obtain the particle size and number concentration (particle size distribution) only from the real-time PM monitor developed. Therefore, the average density of aerosol particles was used to obtain the PM data from the particle size distribution. The $PM_{10/2.5/1}$ results of the PM monitor were compared with the data of the Grimm Dust Monitor (Model 1.108) and a beta ray gauge (Thermo Fisher Scientific). As a result, it was shown that the $PM_{10/2.5/1}$ results obtained by the real-time PM monitor agreed well with the data of the reference devices, and overall, the real-time PM monitor could be used as a PM monitoring device for real-time monitoring of the ambient particles.

Cold Cloud Genesis and Microphysical Dynamics in the Yellow Sea using WRF-Chem Model: A Case Study of the July 15, 2017 Event (WRF-Chem 모델을 활용하여 장마 기간 황해에서 발달하는 한랭운과 에어로졸 미세물리 과정 분석: 2017년 7월 15일 사례)

  • Beom-Jung Lee;Jae-Hee Cho;Hak-Sung Kim
    • Journal of the Korean earth science society
    • /
    • v.44 no.6
    • /
    • pp.578-593
    • /
    • 2023
  • Intense convective activity and heavy precipitation inundated Seoul and its metropolitan area on July 15, 2017. This study investigated the synoptic-scale meteorological drivers of cold cloud genesis of this event. The WRF-Chem (Weather Research and Forecasting model coupled with Chemistry) model was employed to explore the intricate interplay between meteorological factors and the indirect effects of PM2.5 aerosols originating from eastern China. The PM2.5 aerosols' indirect effect was quantified by contrasting outcomes between the comprehensive Aerosol Radiation Interaction experiment (encompassing aerosol radiation feedback, cloud chemistry processes, and wet scavenging in the WRF-Chem model) and ACR (Aerosol Cloud Radiation interaction) experiment. The ACR experiment specifically excluded aerosol radiation feedback while incorporating only cloud chemistry processes and wet scavenging. Results indicated that in the early hours of July 15, 2017, a convergence of warm, moisture-laden airflow originating from southeast China and the East China Sea unfolded over the Yellow Sea. This convergence was driven by the juxtaposition of a low-pressure system over the Chinese mainland and Northwest Pacific high. Notably, at approximately 12 km altitude, the resultant convective clouds were characterized by the presence of ice crystals, a hallmark of continental-origin cold clouds. The WRF-Chem model simulations elucidated the role of PM2.5 aerosols from eastern China, attributing 5.7, 10.4, and 10.8% to cloud water, ice crystal column, and liquid water column formation, respectively, within the developing cold clouds. Thus, this study presented a meteorological mechanism elucidating the formation of deep convective clouds over the Yellow Sea and the indirect effects of PM2.5 aerosols originating from eastern China.

A Strategic Approach for Environmental Conscious Machining (환경친화적 기계가공을 위한 전략적 접근)

  • Hwang, Joon;Chung, Eui-Sik;Liang, Steve Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1997.10a
    • /
    • pp.847-850
    • /
    • 1997
  • This paper presents a strategy to develop the environmentally conscious machining process. To establish the knowledge the analytical and experimental methodology for he prediction of aerosol concentration due to cutting fluid atomization mechanism in machining operation. The established analytical model which is based on atomization theory analyzes the cutting fluid motion and aerosol generation in machining process. The impinging and evaporation experiments were performance to know the particle size ad evaporation rate of cutting fluid. The predictive models can be used as a basis for environmental impact analysis on the shop floor. It can be also facilitate the optimization of cutting fluid usage in achieving a balanced consideration of productivity and environmental consciousness.

  • PDF

Optimization of Cutting Fluids for Environmentally Conscious Machining (환경친화적 기계가공을 위한 절삭유 최적화에 관한 연구)

  • Hwang, Jun;Jung, Eui-Sik;Liang, Steven Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2000.05a
    • /
    • pp.948-951
    • /
    • 2000
  • This paper presents the analytical and experimental methodology for the prediction of aerosol concentration and size distribution due to cutting fluid atomization mechanism in turnining operation. The established analytical model which is based on atomization theory analyzes the cutting fluid motion and aerosol generation in machining process. The impinging and evaporation experiments were performed to know the particle size and evaporation rate of cutting fluid. The predictive models can be used as a basis for environmental impact analysis on the shop floor. It can be also facilitate the optimization of cutting fluid usage in achieving a balanced consideration of productivity and environmental consciousness.

  • PDF

The Role of Fronts on the Vertical Transport of Atmospheric Pollutants (2-D model)

  • Nam, Jae-Cheol
    • Proceedings of the Korean Environmental Sciences Society Conference
    • /
    • 2003.11a
    • /
    • pp.65-68
    • /
    • 2003
  • A quantitative study of the amount of air transported between the boundary layer and the free atmosphere is important for understanding air quality and upper tropospheric ozone, which is a greenhouse gas. Frontal systems are known to be an effective mechanism for the vertical transport of pollutants. Numerical experiments have been performed with a simple two-dimensional front model to simulate vertical transport of trace gases within developing cold fronts. Three different trace gases experiments have been done numerically according to the different initial fields of trace gases such as aerosol, ozone and $H_2O_2$. Trace gas field tilts to the east while the front tilts to the west. Aerosol simulation shows that pollutants can be transported out of the boundary to altitudes of about 10 km. The stratospheric ozone is brought downwards in a tropopause fold behind of the frontal surface. The meridional gradient in trace gas ($H_2O_2$) can cause a complicate structure in the trace field by the meridional advection.

  • PDF

Analysis for Cokes Fracture Behavior using Discrete Element Method (이산요소법을 이용한 코크스 분화 거동 해석)

  • You, Soo-Hyun;Park, Junyoung
    • Particle and aerosol research
    • /
    • v.8 no.2
    • /
    • pp.75-81
    • /
    • 2012
  • The strength of lumped cokes can be represented by some index numbers. Although some indexes are suggested, these indexes are not enough to enlighten fracture mechanism. To find essential mechanism, a computational way, discrete element method, is applied to the uniaxial compression test for cylindrical specimen. The cylindrical specimen is a kind of lumped particle mass with parallel bonding that will be broken when the normal stress and shear stress is over a critical value. It is revealed that the primary factors for cokes fracture are parallel spring constant, parallel bond strength, bonding radius and packing ratio the parallel bond strength and radius of the parallel combination the packing density. Especially, parallel spring constant is directly related with elastic constant and yield strength.

Numerical Simulation of Impactor Collection Efficiency according to Altitude (대기 고도에 따른 입자 포집용 관성 임팩터의 설계 및 포집효율 예측)

  • Kim, Gyuho;Yook, Se-Jin;Ahn, Kang-Ho
    • Particle and aerosol research
    • /
    • v.8 no.1
    • /
    • pp.1-8
    • /
    • 2012
  • In this study, the collection efficiency of inertial impactors was numerically simulated by employing the statistical Lagrangian particle tracking(SLPT) model. The SLPT model was proven to be correct in predicting the impactor collection efficiency, when the numerically obtained collection efficiencies were compared with the experimental data of Marple et al.(1987) at normal pressure level and the experimental data of $Marjam{\ddot{a}}ki$ et al.(2000) at low pressure level. Based on the validation results, balloon-borne impactors with the cut-off sizes of $1{\mu}m$, $2.5{\mu}m$, and $10{\mu}m$ were designed. Then, the sampling flowrates of the inertial impactors, required to keep the cut-off sizes constant at different pressures and temperatures, were estimated according to the altitude.

The Numerical Simulation of Ultrafine $SiO_2$ Particle Fabrication and Deposition by Using the Tube Furnace Reactor (튜브형 가열로 반응기를 이용한 초미립 $SiO_2$ 입자의 제조 및 증착에 대한 수치모사)

  • 김교선;현봉수
    • Journal of the Korean Ceramic Society
    • /
    • v.32 no.11
    • /
    • pp.1246-1254
    • /
    • 1995
  • A numerical model for fabrication and deposition of ultrafine SiO2 particles were proposed in the simplified horizontal MCVD apparatus using tube furnace reactor. The model equations such as energy and mass balance equations and the 0th, 1st and 2nd moment balance equations of aerosols were considered in the reactor. The phenomena of SiCl4 chemical reaction, SiO2 particle formation and coagulation, diffusion and thermophoresis of SiO2 particles were included in the aerosol dynamic equation. The profiles of gas temperature, SiCl4 concentration and SiO2 particle volume were calculated for standard conditions. The concentrations, sizes and deposition efficiencies of SiO2 particles were calculated, changing the process conditions such as tube furnace setting temperature, total gas flow rate and inlet SiCl4 concentration.

  • PDF