• Korean Journal of Pharmacognosy
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• v.54 no.1
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• pp.44-51
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• 2023

Fine dust has emerged as seriously hazardrous particles, which can cause respiratory and cardiovascular diseases. Thus, we have developed a natural complex extract consisted of Codonopsis lanceolata (Siebold & Zucc.) Trautv., Platycodon grandiflorum A. De Candolle, and Glycyrrhiza uralensis Fischer in the ratio of 3 : 5 : 2, which have a beneficial effect on respiratory system. In this study, simultaneous quantitative analysis of marker compounds, lobetyolin, platycodin D, and glycyrrhizic acid in the natural complex extract was developed and validated with high performance liquid chromatography-photodiode array detector. The marker compounds were shown in a large linearity with a correlation coefficient (R²) of 1.000. The limit of detection (LOD) of lobetyolin, platycodin D and glycyrrhizic acid were 5.40 ㎍/mL, 3.94 ㎍/mL and 5.86 ㎍/mL, respectively. The limit of quantification (LOQ) of lobetyolin, platycodin D and glycyrrhizic acid were 16.36 ㎍/mL, 11.94 ㎍/mL and 17.75 ㎍/mL, respectively. The content analysis revealed that the amounts of lobetyolin, platycodin D, and glycyrrhizic acid were 0.039±0.013 mg/g, 0.337±0.048 mg/g, and 1.171±0.003 mg/g, respectively, in the natural complex extract. Therefore, these results could be used as basic data for the standardization and quality control of the natural complex extract.

• Safety and Health at Work
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• v.14 no.3
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• pp.279-286
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• 2023

Background: This study aimed to evaluate the association between exposure to occupational hazards and the metabolic syndrome. A secondary objective was to analyze the additive and multiplicative effects of exposure to risk factors. Methods: This retrospective cohort was based on 31,615 health examinees at the Pusan National University Yangsan Hospital in Republic of Korea from 2012-2021. Demographic and behavior-related risk factors were treated as confounding factors, whereas three physical factors, 19 organic solvents and aerosols, and 13 metals and dust were considered occupational risk factors. Time-dependent Cox regression analysis was used to calculate hazard ratios. Results: The risk of metabolic syndrome was significantly higher in night shift workers (hazard ratio = 1.45: 95% confidence interval = 1.36-1.54) and workers who were exposed to noise (1.15:1.07-1.24). Exposure to some other risk factors was also significantly associated with a higher risk of metabolic syndrome. They were dimethylformamide, acetonitrile, trichloroethylene, xylene, styrene, toluene, dichloromethane, copper, antimony, lead, copper, iron, welding fume, and manganese. Among the 28 significant pairs, 19 exhibited both positive additive and multiplicative effects. Conclusions: Exposure to single or combined occupational risk factors may increase the risk of developing metabolic syndrome. Working conditions should be monitored and improved to reduce exposure to occupational hazards and prevent the development of the metabolic syndrome.

• Safety and Health at Work
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• v.14 no.3
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• pp.287-294
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• 2023

Background: Fruit and vegetable market is an abundant source of bioaerosols. Exposure to organic and inorganic waste and long-term inhalation of bioaerosols during working hours leads to chronic respiratory symptoms. Hence, this study aimed to determine the prevalence of chronic respiratory symptoms and related factors among fruit and vegetable workers compared with the control group in Addis Ababa, Ethiopia. Methods and materials: A comparative cross-sectional study was conducted from 2020 to 2021. Data were entered in EpiData 3.1 and exported to Statistical Package for the Social Sciences (SPSS) version 25. Logistic regressions were computed to depict the data and related factors. The culture method was done to count and compare bacterial and fungal concentrations between fruit and vegetable workers and office workers. Results: In this study, the prevalence of chronic respiratory symptoms (PR = 2.87, 95% confidence interval [CI]: 1.772-4.66) was significantly higher among fruit and vegetable workers (46.7%) than controls (23.4%). Sex (adjusted odds ratio [AOR] = 2.11, 95% CI = 1.12-3.98), educational status (AOR = 1.34, 95% CI = 0.78-2.32), working hours per day (AOR = 3.91, 95% CI = 1.586-9.65), and working department (AOR = 3.20, 95% CI = 0.90-11.40) were associated with chronic respiratory symptoms. Bacterial and fungal concentrations were significantly higher in the air of the vegetable market (276 colony-forming unit) than the air in the workplace of controls (7 colony-forming unit). Conclusion: The fruit and vegetable market workers (greengrocers) had a higher prevalence of chronic respiratory symptoms relative to office workers. Respiratory protective devices should be given to deliver preventive measures.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.337-343
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• 2023

Olivine is a complete solid solution of fayalite and forsterite that is abundant in Earth and extraterrestrial materials such as rocky planets, meteorites, asteroids, and interplanetary dust. Due to the wide range of olivine compositions, diverse olivine standards are required for quantitative mineralogical analysis of olivine-bearing materials. Olivine standards were synthesized using an electric furnace and stainless steel tubes at temperatures ranging from 1000~1100 ℃. Overall, olivine was synthesized covering the full range of composition, with some synthetic impurities and unreacted material. The synthesized olivine showed a linear increase in the unit cell dimension in proportion to the molar ratio of fayalite in the starting materials, and the diffraction intensity was consistent with that of natural olivine. However, iron-rich synthetic olivine samples tend to have a higher content of impurity, suggesting that not all synthetic olivine can be used as a standard material yet, and improvements in the synthesis process, such as using high purity starting materials and control of reaction time and temperature, are required.

• Journal of the Korean earth science society
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• v.37 no.7
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• pp.434-447
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• 2016

This study analyzed mass concentrations of PM10 and PM2.5, as measured at Tae-ahn and Gang-nae, Cheongju in central Korea over the period from 2011 to 2015. Higher mass concentrations of PM10, with the exception of dustfall cases during the period of winter and spring, reflected the influence of a prevailing westerly airflow, while the level of PM10 stayed at a low level in summer, reflecting the influence of North Pacific air mass and frequent rainfall. Accordingly, cases where a daily PM10 average of $81{\mu}gm^{-3}$ or over (exceeding the status of fine dust particles being 'a little bit bad') were often observed during the period of winter and spring, with more cases occurring in parts of Tae-ahn that are located close to the sources of pollutant emission in eastern China. Dustfall usually originated from dust storms made up of particles $2.5{\mu}m$ or over in diameter. However, anthropogenic haze displayed a high composition ratio of particulate less than $2.5{\mu}m$ in diameter. Accordingly, brightness temperature difference (BTD) values from the Communication, Ocean and Meteorological Satellite (COMS) were $-0.5^{\circ}K$ or over in haze with fine particulate. PM10 mass concentrations and NOAA 19 satellite BTD for haze cases were analyzed. Though PM10 mass concentrations were found to be lower than $200{\mu}g\;m^{-3}$, the mass concentration ratio of PM2.5/PM10 was measured as higher than 0.4 and BTD was found to be distributed in the range from -0.3 to $0.5^{\circ}K$. However, the BTD of dustfall cases exceeding $190{\mu}g\;m^{-3}$, were found to be less than 0.4 and BTD was found to be distributed in the range less than $-0.7^{\circ}K$. The result of applying BTD threshold values of the large-scale transport of haze proved to fall into line with the range over which aerosols of MODIS AOD and OMI AI were distributed.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.727-735
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• 2016

This research was conducted to investigate the influence of various pre-planting $NO_3:NH_4$ ratios in the coir dust+peatmoss+perlite (3.5:3.5:3, v/v/v) medium on the growth of tomato plug seedlings (cv. Dotaerang Dia), changes in chemical properties of root media, and tissue nutrient contents. With the fixation of N concentration to $300mg{\cdot}L^{-1}$, the $NO_3:NH_4$ ratios were adjusted to 100:0, 73:27, 50:50, 27:73, 0:100. Then, root media containing various $NO_3:NH_4$ ratios and equal concentration of other essential nutrients were filled into 50-cell plug trays and the seeds of 'Dotaerang Die' tomato were sown. The investigation of seedling growth and tissue analysis for mineral nutrient contents based on the dry weight of above-ground tissue were conducted 6 weeks after sowing. As seedlings grew, the EC decreased quickly and pH increased gradually in the all treatment media. The plant height, fresh weight and dry weight of seedlings in the treatment of 50:50 ($NO_3:NH_4$) were 29.0 cm, 13.7 g, and 1.21 g, respectively, which were the highest among treatments tested. However, the seedlings in the treatment of 0:100 ($NO_3:NH_4$) had 26.5 cm, 11.2 g, and 0.92 g in plant height, fresh weight and dry weight, respectively. These were the poorest among the treatments tested. The tissue contents of N were 2.77 to 3.22% in all the treatments. The treatment of 27:73 ($NO_3:NH_4$) had the highest contents of Fe, Mn and Zn and that of 0:100 ($NO_3:NH_4$) had the lowest contents of Mg, Na, Cu, Mn and Zn among the treatments tested. The results indicate that $NH_4$ ratio should be lower than 50% in the coir dust+peatmoss+perlite (3.5:3.5:3, v/v/v) medium for seedling growth of tomato and the optimum ratio will be used to draw up guide lines for plug seedling production.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.9-15
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• 2019

The purpose of present study is to assess the maximum width of the surface cracks using the histogram analysis of image processing techniques in concrete structures. For this purpose, the concrete crack image is acquired by the camera. The image is Grayscale coded and Binary coded. After Binary coded image is Dilate and Erode coded, the image is then recognized as separated objects by applying Labeling techniques. Over time, dust and stains may occur naturally on the surface of concrete. The crack image of concrete may include shadows and reflections by lighting depending on a surrounding conditions. In general, concrete cracks occur in a continuous pattern and noise of image appears in the form of shot noises. Bilateral Blurring and Adaptive Threshold apply to the Grayscale image to eliminate these effects. The remaining noises are removed by the object area ratio to the Labeled area. The maximum numbers of pixels and its positions in the crack objects without noises are calculated in x-direction and y-direction by Histogram analysis. The widths of the crack are estimated by trigonometric ratio at the positions of the pixels maximum numbers for the Labeled objects. Finally, the maximum crack width estimated by the proposed method is compared to the crack width measured with the crack gauge. The proposed method by the present study may increase the reliability for the estimation of maximum crack width using image processing techniques in concrete surface images.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.4
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• pp.111-119
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• 2008

The runoff coefficient for a block paved area is determined with regional rainfall distribution. The Rational Method is a basic equation of a drainage system design and is a function of runoff coefficient, rainfall intensity and area. A runoff coefficient is the ratio of rainfall intensity and runoff. The rainfall intensity which is a function of the return period and rainfall duration differs by region. Therefore the runoff coefficient varies regionally even though there is the same return period and rainfall duration. The ratio of rainfall intensity and rainfall duration is decided by the loss of rainfall. The constant infiltration capacity of Horton's equation is adopted to determine the loss of rainfall. As time passed, the joint of the block paved area through which the infiltration occurs is covered by pollution material, sandy dust, pollen and is hardened by foot pressure, so the constant infiltration capacity may decrease. Six different sites were selected to verify the assumption of the constant infiltration capacity decrease and 10 year return period. 10, 20, and 30 minute rainfall duration were applied to calculate rainfall intensity. The results indicate that the Horton's constant infiltration capacity decreases over time and the minimum constant infiltration capacity is selected to compute runoff coefficients. The runoff coefficients varied by region ranging from $0.94{\sim}0.84$ for 10 minute of rainfall duration.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.561-574
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• 2013

This study investigates energy fluxes measured near Gangjeong-Goryeong Weir of the Nakdong River of South Korea for more than a year, from July 2011 to September 2012, in order to analyze the applicability of the data for future impact analyses. Each of the two study sites is located in a rural area, surrounded by agricultural fields, and an urban industrial area. Sensible and latent heat fluxes are analyzed according to the wind direction. In the summertime, when the wind blows from the river, sensible heat tends to decrease and latent heat tends to increase at both sites. This result is considered to be caused by moisture transfer from the river. Bowen ratio, energy balance closure, momentum flux, and stability are analyzed as well. The Bowen ratio of the rural agricultural site turns out higher than that of the urban site regardless of the season. The energy balance closure is higher at the agricultural site compared to the urban area, which is mainly due to exclusion of the storage term calculation at the urban site. The momentum flux is greater at the urban site both in winter and summer. The instability lasts longer during daytime and in the summertime, when there is a strong turbulence. The data from these sites are appropriate to be used in analyzing the impact of river in surrounding areas for future studies.

• Clean Technology
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• v.26 no.1
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• pp.22-29
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• 2020

Recently, as the fine dust is increased and the emission regulations of diesel engines have been tightened, interest in diesel soot filtration devices has rapidly increased. There is specifically a demand for the technological development of higher diesel exhaust gas after-treatment device efficiency. As part of this, many studies were conducted to increase exhaust gas treatment efficiency by improving the flow uniformity of the exhaust gas in the diesel particulate filter (DPF) and reducing the pressure drop between the inlet and the outlet of DPF. In this study, the effects of pressure drop by the flow rate and temperature of exhaust gas, DPF I/O ratio, Ash, and PM amount in diesel reduction device were simulated via a 12" diameter DPF and diesel oxidation catalyst (DOC) using ANSYS Fluent. As the flow rate and temperature decreased, the pressure drop decreased, whereas the PM amount affected the pressure drop more than the ash amount and the pressure drop was lower in anisotropic DPF than isotropic DPF. In the case of DPF flow uniformity, it was constant regardless of the various variables of DPF. In ESC and ETC conditions, the filtration efficiency for PM was similar regardless of anisotropic and isotropic DPF, but the filtration efficiency for PN (particle number) was higher in anisotropic DPF than isotropic DPF.