• Journal of Environmental Science International
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• v.7 no.2
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• pp.185-190
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• 1998

$PM_{10}$ concentrations were measured In underground stores located In 4 major cities, Chunchon, Wonju, Donghae and Sockcho, In Kangwon-Do using scattering light Integated type digital dust indicator. Per- sonal exposure to $PM_{10}$ for two women(housekeeper and gaduate students and a man(undergraduate student) were measured also. The dimensional conversion factors for mass concentrations(K) showed some difference among un- derground stores which were 2.0, 2.7, 3.4, 2.6 mg/$m^2$.CPM In chunchon, Wonju, Donghae and Sockcho, respectively. Average PMlo concentrations at underground stores were 178mg/$m^2$ in Chunchon, 141mg$m^2$ in Wonju, 125 mg/$m^2$ Donghe and 59mg/$m^2$) Sockcho. The portion of $PM_{10}$ In total suspended particles was about 50~60% as deight The exposure of graduate student, housekeeper and undergraduate to $PM_{10}$ during 12 hours were 1004. 3 (mg/$m^2$) .hr, 907.0 (mg/$m^2$) hr and 691.2 (mg/$m^2$) hr, respectively. Personal exposure to $PM_{10}$ showed very different according to heP activity pattern and they had more than 90 % of their $PM_{10}$ exposure at Indoor environment.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.13-17
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• 2010

The radioisotope labelling study was carried out for the sediment transport investigation. The fate of suspended solid materials is deeply related to the harbour siltation and the shoreline deformation that take place as a result of the artificial development of coastal area. In the experiment, $^{99m}TcO_4{^-}$ was chemically reduced and labelled in such a way that the labelled particles have the similar settling characteristics with the natural sediment. The radioisotope labelling techniques can be widely used for the natural resource exploration where the hydraulic dynamics of underground water and surface water are of importance.

• Korean Journal of Metals and Materials
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• v.50 no.7
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• pp.523-530
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• 2012

We investigated the experimental method that uses the homogeneous precipitation method to prepare mica flakes-coated rutile-type titania pearlescent pigment with urea as a precipitant. $TiO_2$ particles exhibit a high reflection of lights and optical properties with chemical stabilities, so they are appropriate for coating on luminescent pigments (mica). The coating principle of mi ca coated titania with various thicknesses was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tested by spectrophotometer. Mica with a particle size in the range of $40-60{\mu}m$ was suspended in water, and metal sulphates and urea were added to the mixture, which was heated to boiling. The change in pH was continuously followed. The metal oxide and crystal structure were affected by the conditions of $TiOSO_4$ concentration and reaction time with a sintering temperature the range of $800-1100^{\circ}C$.

• Journal of Environmental Science International
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• v.30 no.12
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• pp.1081-1092
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• 2021

In this study, the effect on the stability of Aerobic Granular Sludge (AGS) caused by an AGS separator was investigated. The AGS separator was a hydrocyclone. The main factors of the AGS separator were filter pore size (0.125~0.600 mm), conical-to-cylindrical ratio (1.5~3.0), and operating time (1~20 min). The AGS/mixed liquor suspended solid (MLSS) ratio gradually increased to 0.500 mm (AGS/MLSS: 84.3±3.0%). AGS was best separated at the conical-to-cylindrical ratio of 2.5 (AGS/MLSS: 84.7±3.3%). As the operating time increased, the AGS separation performance also tended to increase. The shortest AGS separator run time, but the highest AGS separation performance was 10 min (87.0±2.5%). AGS stability was evaluated by operating the selected AGS separator and sequencing batch reactor. The average removal efficiencies of TOC, TCOD_Cr, SS, TN, and TP were 95.7%, 96.9%, 93.0%, 89.0%, and 96.2%, respectively, which met the effluent standards in Korea. In addition, the AGS/MLSS ratio tended to remain constant, and the sludge volume index demonstrated a tendency to decrease from 140 mL/g to 70 mL/g. During the operation, the particles of AGS in optical microscope observations gradually increased.

• Computers and Concrete
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• v.32 no.4
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• pp.399-410
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• 2023

This study proposes a novel use of backpropagated Levenberg-Marquardt neural networks based on computational intelligence heuristics to comprehend the examination of hybrid nanoparticles on the flow of dusty liquid via stretched cylinder. A two-phase model is employed in the present work to describe the fluid flow. The use of desulphated nanoparticles of silver and molybdenum suspended in water as base fluid. The mathematical model represented in terms of partial differential equations, Implementing similarity transformationsis model is converted to ordinary differential equations for the analysis . By adjusting the particle mass concentration and curvature parameter, a unique technique is utilized to generate a dataset for the proposed Levenberg-Marquardt neural networks in various nanoparticle circumstances on the flow of dusty liquid via stretched cylinder. The intelligent solver Levenberg-Marquardt neural networks is trained, tested and verified to identify the nanoparticles on the flow of dusty liquid solution for various situations. The Levenberg-Marquardt neural networks approach is applied for the solution of the hybrid nanoparticles on the flow of dusty liquid via stretched cylinder model. It is validated by comparison with the standard solution, regression analysis, histograms, and absolute error analysis. Strong agreement between proposed results and reference solutions as well as accuracy provide an evidence of the framework's validity.

• International Journal of Molecular Medicine
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• v.43 no.6
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• pp.2516-2522
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• 2019

Particulate matter (PM), a widespread airborne contaminant, is a complex mixture of solid and liquid particles suspended in the air. Recent studies have demonstrated that PM induces oxidative stress and inflammatory reactions, and may cause certain skin diseases. Afzelin is a flavonoid isolated from Thesium chinense Turcz, which has anti-inflammatory, anticancer and antibacterial properties. Therefore, the present study aimed to investigate if afzelin affected inflammatory responses in human keratinocytes exposed to PM. HaCaT cells were treated with PM (25 ㎍/cm2) in the presence or absence of afzelin (200 µM). Here, standard reference material 1649b was used as PM. Cell viability was assessed using the water-soluble tetrazolium salt-1 assay. The generation of reactive oxygen species (ROS) was measured using the dichloro-dihydro-​fluorescein diacetate assay. Gene and protein expression were investigated using reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Levels of secreted inflammatory cytokines were measured using ELISA. The results suggested that afzelin inhibited PM-induced proinflammatory cytokine mRNA expression and protein secretion in HaCaT cells. In addition, afzelin suppressed PM-induced intracellular ROS generation, and p38 mitogen-activated protein kinase and transcription factor activator protein-1 component c-Fos and c-Jun activation. The results indicated that afzelin exerts anti-inflammatory and antioxidant effects in PM-exposed HaCaT. Afzelin may have potential for preventing PM-induced inflammatory skin diseases.

• Journal of Preventive Medicine and Public Health
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• v.4 no.1
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• pp.41-64
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• 1971

During the period from July 1st to the end of November 1970, a survey on air pollution and noise level was made in Seoul, Pusan and Taegu, the three largest cities in Korea. Each city was divided into 4-6 areas; the industrial area, the semi-industrial area, the commercial area, the residential area, the park area and the downtown area. Thirty eight sites were selected from each area. A. Method of Measurement : Dustfall was measured by the Deposit Gauge Method, sulfur oxides by $PbO_2$ cylinder method, suspended particles by the Digital Dust Indicator, Sulfur dioxide ($SO_2$) and Carbon Monoxide (CO) by the MSA & Kitakawa Detector and the noise levels by Rion Sound Survey meter. B. Results: 1. The mean value of dustfall in 3 cities was $30.42ton/km^2/month$, ranging from 8.69 to 95.44. 2. The mean values of dustfall by city were $33.17ton/km^2/month$ in Seoul, 32.11 in Pusan and 25.97 in Taegu. 3. The mean values of dustfall showed a trend of decreasing order of semi-industrial area, downtown area, industrial area, commercial area, residential area, and park area. 4. The mean value of dustfall in Seoul by area were $52.32ton/km^2/month$ in downtown, 50.54 in semi-industrial area, 40.37 in industrial area, 24,19 in commercial area, 16.25 in park area and 15.39 in residential area in order of concentration. 5. The mean values of dustfall in Pusan by area were $48.27ton/km^2/month$ in semi-industrial area, 36.68 in industrial area 25.31 in commercial area, and 18.19 in residential area. 6. The mean values of dustfall in Taegu by area were $36.46ton/km^2/month$ in downtown area, 33.52 in industrial area, 20.37 in commercial area and 13.55 in residential area. 7. The mean values of sulfur oxides in 3 cities were $1.52mg\;SO_3/day/100cm^2\;PbO_2$, ranging from 0.32 to 4.72. 8. The mean values of sulfur oxides by city were $1.89mg\;SO_3/day/100cm^2\;PbO_2$ in Pusan, 1.64 in Seoul and 1.21 in Taegu. 9. The mean values of sulfur oxides by area in 3 cities were $2.16mg\;SO_3/day/100cm^2\;PbO_2$ in industrial area, 1.69 in semi-industrial area, 1.50 in commercial area, 1.48 in downtown area, 1.32 in residential area and 0.94 in the park area, respectively. 10. The monthly mean values of sulfur oxides contents showed a steady increase from July reaching a peak in November. 11. The mean values of suspended particles was $2.89mg/m^3$, ranging from 1.15 to 5.27. 12. The mean values of suspended particles by city were $3.14mg/m^3$ in Seoul, 2.79 in Taegu and 2.25 in Pusan. 13. The mean values of noise level in 3 cities was 71.3 phon, ranging from 49 to 99 phon. 14. The mean values of noise level by city were 73 phon in Seoul, 72 in Pusan, and 69 in Taegu in that order. 15. The mean values of noise level by area in 3 cities showed a decrease in the order of the downtown area, commercial area, industrial area and semi-industrial area, park area and residential area. 16. The comparison of the noise levels by area in 3 cities indicated that the highest level was detected in the downtown area in Seoul and Taegu and in the industrial area in Pusan. 17. The daily average concentration of sulfur dioxides ($SO_2$) in 3 cities was 0.081 ppm, ranging from 0.004 to 0.196. 18. The daily average concentrations of sulfur dioxides by city were 0.092 ppm in Seoul, 0.089 in Pusan and 0.062 in Taegu in that order. 19. The weekly average concentration of carbon monoxides(CO) was 27.59 ppm. 20. The daily average concentrations of carbon monoxides by city were 33.37 ppm. in Seoul, 25.76 in Pusan and 23.65 in Taegu in that order. 21. The concentration of $SO_2$ and CO reaches a peak from 6 p. m. to 8 p. m. 22. About 3 times probably the daily average concentration of CO could be detected in the downtown area probably due to heavy traffic emission in comparison with that in the industial area. 23. As for daily variation of the concentration of $SO_2$ and CO it was found that the concentration maintains relatively higher value during weekdays in the industrial area and on the first part of the week in the downtown area.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.322-333
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• 2005

Total phosphorus (TP) and suspended solids (SS) were measured in the discharge waters from 5 drainage basins of Lake Yongdam, from April, 2002 till March, 2004. The responses of SS and TP to rainfall were analyzed and their loadings into Lake Yongdam were calculated. The inflowing rivers into Lake Yongdam were the Juja River, the Jeongja River, the Jinan River, the Geum River and the Guryang River. Among these rivers Jinan River showed the highest TP that fluctuated very much according to the flow rate. TP and the flow rates (Q) of each river showed positive correlations with empirical relationsip of $TP\;=\;6.32Q^{0.30}$ for the Juia River, $TP\;=\;8.58Q^{0.49}$ for the Jeongia River, $TP\;=\;307.92Q^{0.10}$, for the Jinan River, $TP\;=\;17.91Q^{0.47}$, for the Geum River, $TP\;=\;20.11Q^{0.53}$ for Guryang River. In April 2002 ${\sim}$ March 2003, phosphorus loadings from the Juja River, the Jeongja River, the Jinan River, the Geum River and the Guryang River were calculated to be 3,677, 11,430, 36,412, 89,651, and 42,226 kgP ${\cdot}$ $yr^{-1}$ respectively. And the specific loadings from the Juja River, the Jeongia River, the Jinan River, the Geum River and the Guryang River were calculated to be 0.3, 2.9, 13.6, 9.3, and 13.0 kgP ${\cdot}$ $km^{-2}$ ${\cdot}$ $yr^{-1}$ respectively. In April 2002 ${\sim}$ March 2004, the suspended particles loading from the Juja River, the Jeongia River, the Jinan River, the Geum River and the Guryang River were 673, 1,232, 4,232, 30,902, 80,202 ton ${\cdot}$ $yr^{-1}$ respectively. The Guryang River showed the largest contribution of SS loading.

• Journal of Preventive Medicine and Public Health
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• v.23 no.1 s.29
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• pp.43-56
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• 1990

To evaluate the difference of concentration and mutagenicity of organic pollutants between residential and traffic area of Seoul, air samples were collected in Bulkwang (residential) and Shinchon (traffic) area. Samples were analyzed to measure the concentration of extractable organic matters (EOM) and their subfractions and mutagenicities were tested using Salmonella typhimurium TA 98. The concentrations of polycyclic aromatic hydrocarbons (PAHs) were also measured by gas-chromatography and compared between two areas. The results were as follows ; 1. While the concentration of total suspended particulate (TSP) in residential area was below the environmental standard in annual average, the concentration in traffic area was above the standard and was up to its maximum $256{\mu}g/m^3$ in November. The difference of TSP concentrations in both areas of each month was statistically significant (P<0.05). 2. The concentration of fine particle in traffic area was significantly higher compare to that in residential area and showed statistically significant monthly difference in both areas (P<0.05). The proportion of concentration of fine particle to TSP was 55-68%. 3. Mean concentrations of EOM in residential and traffic areas were $4.3{\mu}g/m^3\;and\;5.3{\mu}g/m^3$ respectively. The proportion of amount of EOM from fine particle to EOM from TSP was 70-88%. 4. While the percentage of polar neutral organic compounds (POCN) of fine particle in Bulkwang's sample was higher compare to Shinchon's sample, the percentage of aliphatic compounds of fine particle in Shinchon's sample was higher compare to Bulkwang's sample. The percentages of PAH fraction were as low as 6-10% in both areas. 5. The mutagenic activity of nit concentration of organic matters extracted from fine particle was higher compare to that of coarse particle and was increased when metabolically activated with S9. Mutagenicities with metabolic activation calculated by unit air volume were significantly different between residential and traffic area, $17\;revertants/m^3$\;and\;22\;revertants/m^3$ respectively. 6. The concentrations of benzo(a)pyrene in fine particle of traffic and residential areas were $3.10ng/m^3\;and\;2.02ng/m^3$ respectively. Sixteen PAHs were higher in samples of traffic area compare to residential area and also concentrations of PAHs in fine particle were higher compare to coarse particle.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2215-2226
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• 2000

Adsorption characteristics for homologous xanthates on quartz surface has been investigated by FT-IR spectroscopy to understand the adsorption mechanism in relation with verification of the influence of surfactants on the stability of hydrophilic suspended solids in aqueous system. Contact angle measurement for water droplets on quartz surface treated with xanthate was also conducted as a supplementary study for spectroscopic investigation to grant a reliability to the interpretation of experimental results. It has been observed that monolayer of ethyl xanthate was formed on quartz surface as the adsorption progressed and double layer of ethyl xanthate was formed eventually through the reverse oriented adsorption of xanthate molecules on the monolayer. Similar trend of adsorption to the case of ethyl xanthate was found for propyl and butyl xanthates and adsorption was observed to occur more rapidly as the number of carbon atom in alkyl group of xanthate homologs increased. Thermodynamic aspect of adsorption was discussed using Young's equation and the variation in adsorption rate was examined according to the concentration of ethyl xanthate. Based on the result, it has been concluded that the adsorption features of surfactant on substrate in aquatic system is governed by molecular structure and concentration of surfactant and its residual time in aqueous environment as dissolved state also influences greatly the stability of hydrophilic suspended particles.