• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.548-558
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• 2013

In this work, laser induced breakdown spectroscopy (LIBS) is used to investigate soil samples collected from different desert areas of Riyadh city in Saudi Arabia. Both qualitative analysis and plasma parameters are studied via the observed LIBS spectra. These experiments have been done using a Spectrolaser-7000 system with 50 mJ fundamental wavelength of Nd:YAG laser and detection delay time of 1 microsecond. Many spectral lines are highly resolved for many elements like Al, Fe, Mg, Si, Mn, Na, Ca and K. The electron temperatures Te and electron densities Ne, for the constituent of generated LIBS plasma, are determined for all the collected samples. It is found that both Te and Ne vary from one desert area to other. This variation is due to the change of the elemental concentration in different desert areas that affects the sample's matrices. Time dependent measurements have also been performed on the soil samples. While the signal-to-base ratio (SBR) reached its optimal value at 1 microsecond, the plasma parameters Ne and Te reach values of $4{\times}10^{17}cm^{-3}$ and 9235 K, respectively, at 2.5 microsecond. The later indicate that the plasma cooling processes are slow in comparison to the previously observed results for metallic samples. The observed results show also that in the future it is possible to enhance the exploitation of LIBS in the remote on-line environmental monitoring application, by following up only the values of Ne and Te for one element of the soil desert sample using an optical fiber probe.

• Fashion & Textile Research Journal
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• v.24 no.2
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• pp.260-266
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• 2022

Cellulose fiber is a material used in various fields. It is the most used type of fiber because of its excellent hygroscopicity and dyeability. Recently, as natural fiber materials have been highlighted due to the influence of eco-friendliness and well-being, bamboo fiber has become a commonly used eco-friendly fiber. Cellulose fibers are part of the -OH hydroxyl group, which means they are more chemically reactive than synthetic fibers. In this study, the cationization properties of bamboo-cotton blended fabrics cationized using CHPTAC (3-chloro-2-hydroxypropyl trimethyl ammonium chloride) in the PDC (padding-drying-curing) method were investigated. Various characteristics according to cationization were studied through elemental analysis, FT-IR (fourier-transform infrared spectroscopy) analysis, X-ray diffraction analysis, TGA (thermogravimetric) analysis, and SEM (scanning electron microscope) analysis. The nitrogen content of the cationized bamboo-cotton blended fabric increased with an increase in the concentration of the cationizing agent CHPTAC, and it was seen to be highly bound to cellulose molecules. As a result of the FT-IR analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics were seen to be typical cellulose. As a result of the X-ray diffraction analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics showed typical cellulose I structures. As a result of the X-ray diffraction analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics showed typical cellulose I structures. As the cationization progressed, micropores appeared on the surface of the blended fabric.

• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.39-50
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• 2015

Stabilization of heavy metals such as Pb, Cd, Zn, and Cu was evaluated in contaminated soil treated with poultry manure (PM) as well as its biochars pyrolyzed at $300^{\circ}C$ (PBC300) and $700^{\circ}C$ (PBC700) at the application rates of 2.5, 5.0, and 10.0 wt% along with the control, prior to 21-days incubation. After incubation, soil pH was increased from 6.94 (control) to 7.51, 7.24, and 7.88 in soils treated with PM 10 wt%, PBC300 10 wt%, and PBC700 10 wt% treatments, respectively, mainly due to alkalinity of treatments. In the soil treated with PM, the concentrations of the toxicity characteristic leaching procedure (TCLP)-extractable Pb, Cd, Zn, and Cu were increased by up to 408, 77, 24, and 955%, respectively, compared to the control. These increases may possibly be associated with an increased dissolved organic carbon concentration by the PM addition. However, in the soil treated with PBC700, TCLP-extractable Pb, Cd, Zn, and Cu concentrations were reduced by up to 23, 38, 52, and 36%, respectively, compared to the control. Thermodynamic modelling using the visual MINTEQ was done to predict the precipitations of $Pb(OH)_2$, $Cu(OH)_2$ and P-containing minerals, such as chloropyromorphite [$Pb_5(PO_4)_3Cl$] and hydroxypyromorphite [$Pb_5(PO_4)_3OH$], in the PBC700 10 wt% treated soil. The SEM-elemental dot mapping analysis further confirmed the presence of Pb-phosphate species via dot mapping of PBC700 treated soil. These results indicate that the reduction of Pb concentration in the PBC700 treated soil is related to the formations of chloropyromorphite and hydroxypyromorphite which have very low solubility.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.567-587
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• 2018

A severe haze event occurred in October 2015 in Gwangju, Korea. In this study, the driving chemical species and the formation mechanisms of $PM_{2.5}$ pollution were investigated to better understand the haze event. Hourly concentrations of $PM_{2.5}$, organic and elemental carbon, water-soluble ions, and elemental constituents were measured at the air quality intensive monitoring station in Gwangju. The haze event occurred was attributed to a significant contribution (72.3%) of secondary inorganic species concentration to the $PM_{2.5}$, along with the contribution of organic aerosols that were strongly attributed to traffic emissions over the study site. MODIS images, weather charts, and air mass backward trajectories supported the significant impact of long-range transportation (LTP) of aerosol particles from northeastern China on haze formation over Gwangju in October 2015. The driving factor for the haze formation was stagnant atmospheric flows around the Korean peninsula, and high relative humidity (RH) promoted the haze formation at the site. Under the high RH conditions, $SO{_4}^{2-}$ and $NO_3{^-}$ were mainly produced through the heterogenous aqueous-phase reactions of $SO_2$ and $NO_2$, respectively. Moreover, hourly $O_3$ concentration during the study period was highly elevated, with hourly peaks ranging from 79 to 95ppb, suggesting that photochemical reaction was a possible formation process of secondary aerosols. Over the $PM_{2.5}$ pollution, behavior and formation of secondary ionic species varied with the difference in the impact of LTP. Prior to October 19 when the influence of LTP was low, increasing rate in $NO_3{^-}$ was greater than that in $NO_2$, but both $SO_2$ and $SO{_4}^{2-}$ had similar increasing rates. While, after October 20 when the impact of haze by LTP was significant, $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations increased significantly more than their gaseous precursors, but with greater increasing rate of $NO_3{^-}$. These results suggest the enhanced secondary transformation of $SO_2$ and $NO_2$ during the haze event. Overall, the result from the study suggests that control of anthropogenic combustion sources including vehicle emissions is needed to reduce the high levels of nitrogen oxide and $NO_3{^-}$ and the high $PM_{2.5}$ pollution occurred over fall season in Gwangju.

• Economic and Environmental Geology
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• v.43 no.3
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• pp.211-222
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• 2010

A batch experiment was carried out to investigate a variation of Sr concentration and $^{87}Sr/^{86}Sr$ ratio in the solution by water-rock interaction. The experiments were conducted at room temperature using two kinds of granites (biotite granite and garnet-bearing granite), de-ionized water. surface water. Water/rock ratio was 1:1. For comparison, we also performed another experiment under water/rock condition of 10:1. Then, the concentration of the cations and anions in the solutions showed severe variation during water/rock interaction. However, after sometime, the $^{87}Sr/^{86}Sr$ ratio of the solution moved to the $^{87}Sr/^{86}Sr$ ratio of the rocks and showed relatively constant value. This suggests that the $^{87}Sr/^{86}Sr$ ratio between water and rock becomes to be stable faster than the elemental equilibration of the element in the solution, and is not affected by interaction condition. Therefore, $^{87}Sr/^{86}Sr$ ratio of the groundwater may be useful in calculating the mixing ratio between different aquifer.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.642-655
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• 2013

In this study, semi-continuous measurements of $PM_{2.5}$ mass, organic and elemental carbon (OC and EC), black carbon (BC), and ionic species concentrations were made for the period of April 03~13, 2012, at a South Area Supersite at Gwangju. Possible sources causing the high concentrations of major chemical species in $PM_{2.5}$ observed during a haze episode were investigated. The measurement results, along with meteorological parameters, gaseous pollutants data, air mass back trajectory analyses and PSCF (potential source contribution function) results, were used to study the haze episode. Substantial enhancements of OC, EC, BC, $K^+$, $SO{_4}^{2-}$, $NO{_3}{^-}$, $NH{_4}{^+}$, and CO concentrations were closely associated with air masses coming from regions of forest fires in southeastern China, suggesting likely an impact of the forest fires. Also the PSCF maps for EC, OC, $SO{_4}^{2-}$, and $K^+$ demonstrate further that the long-range transport of smoke plumes of forest fires detected over the southeastern China could be a possible source of haze phenomena observed at the site. Another possible source leading to haze formation was likely from photochemistry of precursor gases such as volatile organic compounds, $SO_2$, and $NO_2$, resulting in accumulation of secondary organic aerosol, $SO{_4}^{2-}$ and $NO{_3}{^-}$. Throughout the episode, local wind directions were between 200 and $230^{\circ}C$, where two industrial areas are situated, with moderate wind speeds of 3~5 m/s, resulting in highly elevated concentration of $SO_2$ with a maximum of 15 ppb. The $SO{_4}^{2-}$ peak occurring in the afternoon hours coincided with maximum ambient temperature ($24^{\circ}C$) and ozone concentration (~100 ppb), and were driven by photochemistry of $SO_2$. As a result, the pattern of $SO{_4}^{2-}$ variations in relation to wind direction, $SO_2$ and $O_3$ concentrations, and the strong correlation between $SO_2$ and $SO{_4}^{2-}$ ($R^2=0.76$) suggests that in addition to the impact of smoke plumes from forest fires in the southeastern China, local $SO_2$ emissions were likely an important source of $SO{_4}^{2-}$ leading to haze formation at the site.

• Conservation Science in Museum
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• v.1
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• pp.61-74
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• 1999

Elemental analysis of 40 glass samples from the Northern Tomb and the Southern Tomb of Hwangnam-daech'ong No. 98 was performed. Fourteen compositions of each sample were analyzed quantitatively by SEM-EDS and glass samples were classified by multivariate analysis such as PCA. All of 40 samples were confirmed to be Na₂O-CaO-SiO₂ system with about 20% of Na₂O. Samples were classified into two groups by doing PCA on concentrations of 5 major elements(SiO₂, Al₂O₃, Na₂O, CaO and K₂O). Samples included in group I showed the concentration of Al₂O₃ is about 9.7% and that of CaO, about 2.2%. In group II, concentration of Al₂O₃ is about 3.2% and that of CaO, about 4.9%. Especially yellow grains embedded in sample No. 12 were shown to be PbSnO₃ by micro XRD, which was the first coloring material ever found in Korea. Lead isotope ratios of samples No. 12 and No. 17 which contained lead were measured by TIMS. The origin of lead was traced by means of multivariate analysis such as SLDA. The result showed that lead from southern China and southern Korea had been used for making glass.

• Journal of the Korean GEO-environmental Society
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• v.11 no.1
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• pp.35-43
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• 2010

The main purpose of this study is to offer informations about the current conditions and basic data of sediments for the urban streams in the Busan city. Total 14 urban streams were selected and sediment samples were collected. Then, It was investigated the sediment qualities though the measurement of pH, proximate analysis, elemental analysis, COD, organic carbon content, volatile solid content and heavy metal concentration. Results show that COD, organic carbon content, volatile solid content and heavy metal concentration of sediment are determined in the range of $1.20{\sim}75.07mg\;L^{-1}$, 0.19~11.54%, 0.23~34.21% and $0.4{\sim}732.6mg\;kg^{-1}$, respectively. Finally, Analysis data of sediments were compared with USEPA sediment quality standards and ontario sediment quality guidelines. As a result, when compared with USEPA sediment quality standards, total 9 samples were evaluated as heavily polluted and total 3 samples were evaluated as moderately polluted. But, when compared with ontario sediment quality guidelines, total 3 samples were evaluated as Severe effect level and total 10 samples were evaluated as lowest effect level.

• Asian Journal of Atmospheric Environment
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• v.9 no.1
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• pp.66-77
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• 2015

In order to survey the seasonal variation of the chemical composition of particulate matter of $2.5{\mu}m$ or less ($PM_{2.5}$), $PM_{2.5}$ was sampled from 8 February 2013 to 31 March 2014 in an industrial area of Chiba Prefecture, Japan. Chemical measurements of the sample included: ionic components ($Na^+$, $NH_4{^+}$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$), carbonaceous components - organic carbon (OC) and elemental carbon (EC), and water-soluble organic carbon (WSOC). Also, secondary organic carbon (SOC) was measured based using the EC tracer method, and char-EC and soot-EC were calculated from the analytical results. The data obtained were interpreted in terms of temporal variation. Of the overall mean value of $PM_{2.5}$ mass concentration obtained during the study period, ionic components, OC and EC accounted for 45.3%, 19.7%, and 8.0%, respectively. $NO_3{^-}$ showed a unique seasonal distribution pattern due to a dependence on temperature and absolute humidity. It was estimated that an approximate temperature of $14^{\circ}C$, and absolute humidity of $7g/m^3$ were critical for the reversible reaction of $NH_4NO_3(p){\leftrightharpoons}NH_3(g)+HNO_3(g)$. The amount of OC and EC contributing to the monthly $PM_{2.5}$ mass concentration was higher in autumn and winter compared to spring and summer. This result could be attributed to the impact of burning biomass, since WSOC and the ratio of char-EC/soot-EC showed a similar pattern during the corresponding period. From the comparison of monthly WSOC/OC values, a maximum ratio of 83% was obtained in August (summer). The WSOC and estimated SOC levels derived from the EC tracer method correlated (R=0.77) in summer. The high occurrence of WSOC during summer was mainly due to the formation of SOC by photochemical reactions. Through long-term observation of $PM_{2.5}$ chemical components, we established that the degree to which the above-mentioned factors influence $PM_{2.5}$ composition, fluctuates with seasonal changes.

• Atmosphere
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• v.27 no.1
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• pp.41-54
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• 2017

Organic carbon (OC) and elemental carbon (EC) in $PM_{2.5}$ were measured using Sunset OC/EC Field Analyzer at Seoul Hwangsa Monitoring Center from March to April, 2016. The mean concentrations of OC and EC during the entire period were $4.4{\pm}2.0{\mu}gC\;m^{-3}$ and $1.4{\pm}0.6{\mu}gC\;m^{-3}$, respectively. OC/EC ratio was $3.4{\pm}1.0$. The average concentrations of $PM_{10}$ and $PM_{2.5}$ were $57.4{\pm}25.9$ and $39.7{\pm}19.8{\mu}g\;m^{-3}$, respectively, which were detected by an optical particle counter. The OC and EC peaks were observed in the morning, which were impacted by vehicle emission, however, their diurnal variations were not noticeable. This is determined to be contributed by the long-range transported OC or secondary formation via photochemical reaction by volatile organic compounds at afternoon. A conditional probability function (CPF) model was used to identify the local source of pollution. High concentrations of $PM_{10}$ and $PM_{2.5}$ were observed from the westerly wind, regardless of wind speed. When wind velocity was high, a mixing plume of dust and pollution during long-range transport from China in spring was observed. In contrast, pollution in low wind velocity was from local source, regardless of direction. To know the effect of long-range transport on pollution, a concentration weighted trajectory (CWT) model was analyzed based on a potential source contribution function (PSCF) model in which 75 percentiles high concentration was picked out for CWT analysis. $PM_{10}$, $PM_{2.5}$, OC, and EC were dominantly contributed from China in spring, and EC results were similar in both PSCF and CWT. In conclusion, Seoul air quality in spring was mainly affected by a mixture of local pollution and anthropogenic pollutants originated in China than the Asian dust.