The High Order WENO Scheme on the Adaptive Mesh

Daeki Yoon,Hongjoong Kim,Woonjae Hwang 한국산업응용수학회 2009 한국산업응용수학회 학술대회 논문집 Vol.2009 No.5

The paper is concerned with the high order accurate computational method on hyperbolic conservationa law using weighted essentially non-oscillatory (WENO) scheme when nonuniform grids are adaptively introduced near a shock or a contact discontinuity. We apply the WENO scheme on nonuniform spatial grids, and high level of mesh refinement is introduced only in the region where more accurate computation is required such as points of discontinuity or sharp transition layer. The scheme estimates cell averages using the ENO-based interpolation when cells are merged or split. Numerical experiments show that the suggested method preserve the order of the WENO method on the adaptive mesh and that the method can be performed for a sufficiently long time with less computational cost.

LATE-TIME VORTEX DYNAMICS OF HYDRODYNAMIC INSTABILITIES

Sung-Ik SOHN,Daeki YOON,Woonjae HWANG 한국산업응용수학회 2010 한국산업응용수학회 학술대회 논문집 Vol.5 No.2

The late-time nonlinear evolutions of interfaces subject to a parallel shear flow and the gravitational acceleration, known as the Kelvin-Helmholtz and Rayleigh-Taylor instabilities, are studied by the vortex sheet model. We perform long-time simulations for the vortex sheet by using the point vortex method, and investigate late-time dynamics of the unstable interfaces. We apply an adaptive point insertion procedure and the WENO scheme to the vortex method, to handle the nonuniform distribution of point vortices and enhance the resolution. Our adaptive vortex method successfully simulates chaotically distorted interfaces with fine resolutions. Various late-time dynamics such as a secondary instability and the reacceleration phenomena of the hydrodynamic instabilities are discussed.

Long-time simulations of the Kelvin-Helmholtz instability using an adaptive vortex method.

Sohn, Sung-Ik,Yoon, Daeki,Hwang, Woonjae Published by the American Physical Society through 2010 Physical review. E, Statistical, nonlinear, and so Vol.82 No.4

<P>The nonlinear evolution of an interface subject to a parallel shear flow is studied by the vortex sheet model. We perform long-time computations for the vortex sheet in density-stratified fluids by using the point vortex method and investigate late-time dynamics of the Kelvin-Helmholtz instability. We apply an adaptive point insertion procedure and a high-order shock-capturing scheme to the vortex method to handle the nonuniform distribution of point vortices and enhance the resolution. Our adaptive vortex method successfully simulates chaotically distorted interfaces of the Kelvin-Helmholtz instability with fine resolutions. The numerical results show that the Kelvin-Helmholtz instability evolves a secondary instability at a late time, distorting the internal rollup, and eventually develops to a disordered structure.</P>

Modification of Hargreaves Equation Coefficient to Estimate Reference Evapotranspiration in Gangwondo

Youngho Seo,Soojeong Lim,Sujeong Heo,Byeongsung Yoon,Sooyoung Hong,Younghak Park,Daeki Hong 한국토양비료학회 2019 한국토양비료학회지 Vol.52 No.1

Reference evapotranspiration (ET0) can be estimated using Hargreaves equation with temperature data alone. The equation has a tendency to overestimate for regions of high relative humidity and to underestimate for regions of wind speed greater than 3 m s<SUP>-1</SUP>. The study was conducted to determine Hargreaves equation coefficient in 11 regions in Gangwondo by comparing ET0 determined by modified Hargreaves equation with ET0 by the FAO Penman-Monteith equation. The Penman-Monteith ET0 values were determined using the weather data including solar duration, air temperature, humidity, and wind speed for 11 weather stations in Gangwondo from 2007 to 2017. The modified Hargreaves coefficients for inland regions such as Chuncheon, Hongcheon, Cheorwon, Wonju, Inje, Yeongwol, Daegwallyeong, and Taebaek ranged from 0.00181 to 0.00199, less than the default value 0.0023. The modified coefficients for coastal regions such as Gangneung, Sokcho, and Donghae ranged from 0.00275 to 0.00302, greater than the default value. Modified Hargreaves ET0 using modified coefficients reduced root mean square error (RMSE) from 0.84 mm d<SUP>-1</SUP> to 0.69 mm d<SUP>-1</SUP> and increased Nash-Sutcliffe coefficient (NSC) from 0.69 to 0.78 compared with original Hargreaves ET0. Therefore the modified Hargreaves coefficients obtained from the study can provide more accurate ET0 estimates than using original default value by considering regional climate characteristics in Gangwondo.

Antibiotic Uptake Reducing Effect of Zeolite and Shell Meal Fertilizer Amendment for Lettuce (Lactuca sativa L.) Cultivation Fertilized with Chicken Manure Compost

Seo, Youngho,Lim, Soojeong,Choi, Seungchul,Heo, Sujeong,Yoon, Byeongsung,Park, Younghak,Hong, Daeki Korean Society of Soil Science and Fertilizer 2018 한국토양비료학회지 Vol.51 No.1

The veterinary antibiotics treated to livestock have a potential risk to reach to soil and water environment, and eventually be taken up by plants. The objective of the study was to investigate the effect of zeolite and shell meal fertilizer amendment on antibiotic uptake by plant when veterinary antibiotics in chicken manure compost were applied to agricultural land. Model antibiotics used in the study were chlortetracycline (CTC), tylosin (TYL), and sulfamethazine (SMT). Chlortetracycline level in lettuce was decreased to less than $0.08ug\;kg^{-1}$ by application of zeolite as compared with about $0.26ug\;kg^{-1}$ for control without amendment on 33 days after transplanting. Tylosin was not detected for all the treatment. Sulfamethazine levels in lettuce ranged from 11 to $19{\mu}g\;kg^{-1}$ on a fresh weight basis and gradually decreased with time. Zeolite application decreased the SMT levels in lettuce by greater extent than shell meal fertilizer amendments. Results from the 61-d greenhouse experiment imply that application of zeolite at a rate of $1.5Mg\;ha^{-1}$ or shell meal fertilizer at a rate of $2.0Mg\;ha^{-1}$ can reduce CTC and SMT concentration in lettuce cultivated in soil fertilized with antibiotic-contaminated chicken manure compost.

Aeration Effect on Degradation of Veterinary Antibiotics in Swine Slurry

Seo, Youngho,Lim, Soojeong,Choi, Seungchul,Heo, Sujeong,Yoon, Byeongsung,Park, Younghak,Hong, Daeki Korean Society of Soil Science and Fertilizer 2018 한국토양비료학회지 Vol.51 No.1

A portion of the veterinary antibiotics administrated to livestock are generally excreted via feces and urine. Tetracyclines and tylosin have a greater priority of environmental risk in Korea based on the consumption and the potential to reach soil and water environment. The antibiotics in animal byproducts need to be reduced or eliminated before they are applied to agricultural lands through composting or other agricultural practices. The objective of the study was to investigate the effect of aeration on degradation of antibiotics during storage of swine slurry. Two antibiotics, tetracycline (TC) and tylosin (TYL), were detected from the swine slurry used in the study. One hour aeration per day for 62 days reduced TC concentration from 199 to $43ng\;L^{-1}$ compared with $104ng\;L^{-1}$ without aeration. Aeration for three and six hours decreased TC level to 30 and $23ng\;L^{-1}$, respectively. The dissipation of TC was fitted with a first-order kinetic model. Aeration for 1, 3, and 6 hours every day increased the first-order rate constant, k, from $0.011day^{-1}$ under anaerobic condition to 0.022, 0.026, and $0.037day^{-1}$, respectively. For TYL, aeration during storage of swine slurry enhanced k from $0.0074day^{-1}$ to 0.014, 0.018, and $0.031day^{-1}$ for 1, 3, and 6 hours per day, respectively. For liquid swine slurry, biotic processes can be more effective for dissipation of antibiotics than abiotic processes because of low organic matter and high water content. These results suggest that aeration can increase the degradation rate of antibiotics during storage of swine slurry.

Antibiotic Uptake Reducing Effect of Zeolite and Shell Meal Fertilizer Amendment for Lettuce (Lactuca sativa L.) Cultivation Fertilized with Chicken Manure Compost

Youngho Seo,Soojeong Lim,Seungchul Choi,Sujeong Heo,Byeongsung Yoon,Younghak Park,Daeki Hong 한국토양비료학회 2018 한국토양비료학회지 Vol.51 No.1

The veterinary antibiotics treated to livestock have a potential risk to reach to soil and water environment, and eventually be taken up by plants. The objective of the study was to investigate the effect of zeolite and shell meal fertilizer amendment on antibiotic uptake by plant when veterinary antibiotics in chicken manure compost were applied to agricultural land. Model antibiotics used in the study were chlortetracycline (CTC), tylosin (TYL), and sulfamethazine (SMT). Chlortetracycline level in lettuce was decreased to less than 0.08 ug kg<SUP>-1</SUP> by application of zeolite as compared with about 0.26 ug kg<SUP>-1</SUP> for control without amendment on 33 days after transplanting. Tylosin was not detected for all the treatment. Sulfamethazine levels in lettuce ranged from 11 to 19 μg kg<SUP>-1</SUP> on a fresh weight basis and gradually decreased with time. Zeolite application decreased the SMT levels in lettuce by greater extent than shell meal fertilizer amendments. Results from the 61-d greenhouse experiment imply that application of zeolite at a rate of 1.5 Mg ha<SUP>-1</SUP> or shell meal fertilizer at a rate of 2.0 Mg ha<SUP>-1</SUP> can reduce CTC and SMT concentration in lettuce cultivated in soil fertilized with antibiotic-contaminated chicken manure compost.

Aeration Effect on Degradation of Veterinary Antibiotics in Swine Slurry

Youngho Seo,Soojeong Lim,Seungchul Choi,Sujeong Heo,Byeongsung Yoon,Younghak Park,Daeki Hong 한국토양비료학회 2018 한국토양비료학회지 Vol.51 No.1

A portion of the veterinary antibiotics administrated to livestock are generally excreted via feces and urine. Tetracyclines and tylosin have a greater priority of environmental risk in Korea based on the consumption and the potential to reach soil and water environment. The antibiotics in animal byproducts need to be reduced or eliminated before they are applied to agricultural lands through composting or other agricultural practices. The objective of the study was to investigate the effect of aeration on degradation of antibiotics during storage of swine slurry. Two antibiotics, tetracycline (TC) and tylosin (TYL), were detected from the swine slurry used in the study. One hour aeration per day for 62 days reduced TC concentration from 199 to 43 ng L<SUP>-1</SUP> compared with 104 ng L<SUP>-1</SUP> without aeration. Aeration for three and six hours decreased TC level to 30 and 23 ng L<SUP>-1</SUP>, respectively. The dissipation of TC was fitted with a first-order kinetic model. Aeration for 1, 3, and 6 hours every day increased the first-order rate constant, k, from 0.011 day<SUP>-1</SUP> under anaerobic condition to 0.022, 0.026, and 0.037 day<SUP>-1</SUP>, respectively. For TYL, aeration during storage of swine slurry enhanced k from 0.0074 day<SUP>-1</SUP> to 0.014, 0.018, and 0.031 day<SUP>-1</SUP> for 1, 3, and 6 hours per day, respectively. For liquid swine slurry, biotic processes can be more effective for dissipation of antibiotics than abiotic processes because of low organic matter and high water content. These results suggest that aeration can increase the degradation rate of antibiotics during storage of swine slurry.

The Relationship between Epidemiologic Factors and Usage Pattern of Hair Care Products in Korea

( Kyung-duck Park ),( Byung Cheol Park ),( Ki Hyun Sung ),( Eunyoung Lee ),( Taewon Lee ),( Daeki Yoon ),( Kyu Bong Kim ),( Gyeong Hun Park ),( Il Yong Park ),( Myung Hwa Kim ) 대한피부과학회 2019 Annals of Dermatology Vol.31 No.3

Background: For hair care products that are used almost everyday, it is important to estimate the cumulative dosage of long-term exposure and to assess the effects on the human body. Little data are available to evaluate actual daily usage in Asian populations. Objective: Reliable exposure data for hair care products is essential to conduct safety assessments. Methods: We evaluated the actual usage pattern and amounts by checking the daily log over a 2-week period, to obtain all the data regarding the participants’ hair care preferences. And, statistical analyses were conducted to analyze the daily use amount (g/d) and daily usage per hair length (g/cm/d), and other variables by sex, age group, and hair oiliness. Results: Throughout this study, we found that female users consumed significantly larger daily amounts of shampoo and rinse. Male groups used more hair gel and spray than female groups. Interestingly, all the hair care products studied scored higher levels of usage among men when calibrated per unit length. Koreans tend to use lesser amount of rinse although their hairs are usually thicker than the Western hairs. Conclusion: This study provides exposure information for commonly used hair care products, which will be useful for risk assessment purposes. (Ann Dermatol 31(3) 307∼314, 2019)