• Corrosion Science and Technology
• /
• v.17 no.4
• /
• pp.154-165
• /
• 2018

During the process of sulfur dioxide removal, flue gas desulfurization equipment provides a serious internal corrosion environment in creating sulfuric acid dew point corrosion. Therefore, the utilities must use the excellent corrosion resistance of steel desulfurization facilities in the atmosphere. Until now, the trend in developing anti-sulfuric acid steels was essentially the addition of Cu, in order to improve the corrosion resistance. The experimental alloy used in this study is Fe-0.03C-1.0Mn-0.3Si-0.15Ni-0.31Cu alloys to which Ru, Zn and Ta were added. In order to investigate the effect of $H_2SO_4$ concentration and the alloying elements, chemical and electrochemical corrosion tests were performed. In a low concentration of $H_2SO_4$ solution, the major factor affecting the corrosion rate of low alloy steels was the exchange current density for $H^+/H_2$ reaction, while in a high concentration of $H_2SO_4$ solution, the major factors were the thin and dense passive film and resulting passivation behavior. The alloying elements reducing the exchange current density in low concentration of $H_2SO_4$, and the alloying elements decreasing the passive current density in high concentration of $H_2SO_4$, together play an important role in determining the corrosion rate of Cu-bearing low alloy steels in a wide range of $H_2SO_4$ solution.

• Journal of Preventive Medicine and Public Health
• /
• v.34 no.4
• /
• pp.316-322
• /
• 2001

Objectives : To explore the possible effect of an interaction between summertime heat waves and ozone on cardiopulmonary mortality during the 1994 heat wave in Korea. Methods : The unusually hot summer of 1994 in Korea was defined as the heat wave in this study. We examined the associations of air pollutants with daily cardiopulmonary deaths between 1991-1995, considering the product term of the heat wave and each pollutant, weather and time trends. Results : During the heat wave, while temperatures were uniformly higher than those of other summers, the within-heat-wave difference in mortality paralleled that in the regional ozone levels. In terms of the influence of the heat wave, the results of ozone were different to those of total suspended particles (TSP) and sulfur dioxide $(SO_2)$. The ozone association (relative risk (RR) : 1.036; 95% confidence interval (CI) = 1.018-1.054) was observed only under heat wave conditions, while the TSP (RR : 1.006, 95% CI = 0.999-1.012) and the $SO_2$ (RR = 1.018, 95% CI : 1.011-1.024) associations were found under normal weather conditions (per interquartile increase of each pollutant; results of three pollutants model). The ozone association under heat wave was attributable to the statistical interaction between the heat wave and ozone. Conclusions : These results support the possibility of a biological synergy between the heat wave and ozone, one that is not evident between the heat wave and other major pollutants like particles or $SO_2$.

• Korean Journal of Agricultural Science
• /
• v.48 no.2
• /
• pp.241-250
• /
• 2021

This investigation assessed the berry quality after two months of low-temperature storage (3 ± 1℃) of 'Shine Muscat' grapes, which were treated with CPPU (N-[2-chloro-4-pyridyl]-N'-phenylurea) or TDZ (1-phenyl-3-[1,2,3-thiadiazol-5-yl] urea) in combination with gibbrellic acid (GA₃). The berry shatter rate was the lowest (1%) in 4 cm + CPPU treatment, while it was the highest (2.4%) in 3 cm floral length treated with CPPU. On the other hand, the 4 cm + TDZ treatment resulted in a shatter rate of 2.0%, which was twice as high as that observed after 4 cm + CPPU treatment. The 4 cm + TDZ treatment resulted in a 5.5% berry decay rate, which was the highest among all treatments. Alternatives to using a sulfur dioxide (SD) pad to maintain the quality of 'Shine Muscat' grapes, namely, using ethylene scrubbers (ESs, 3 g × 2 sachet) and alcohol releasers (ARs, 2 g × 2 sachet) in a 2 kg carton package for export, were explored in this study. The berry shatter rate with ES treatment (1.0%) was found to be comparable to that with SD treatment (0.6%) during three months of cold storage. Regarding the berry decay rate, that of the untreated control surged to 36.0% in the three months of storage, followed by 19.9% and 15.5% in samples subjected to AR and ES treatments respectively. Compared with the untreated control, the samples subjected to SD treatment showed a decay rate of 2.2%, which was the most effective in reducing berry decay by 95%. These results demonstrated that SD pad treatment of 'Shine Muscat' grapes was the most effective method of maintaining berry quality, and ES treatment partially reduced the berry shatter and berry decay rates.

• Korean Journal of Metals and Materials
• /
• v.48 no.4
• /
• pp.277-288
• /
• 2010

The hot corrosion properties of heat-resistant steels were investigated in an oxidation atmosphere including artificial ash and sulfur dioxide. The heat-resistant steels of T22, T92, T122, T347HFG, Super304H and HR3C were evaluated at 620, 670 and $720^{\circ}C$ for 400 hours. The relationship between the corrosion rate and the temperature followed a bell-shaped curve with a peak rate at around $670^{\circ}C$. The corrosion rates showed a decreasing tendency as the chrome contents of these steels increased from 2.15 wt.% to 24.5 wt.%, and austenitic steels had a lower corrosion rate than ferritic steels. Sulfidation by $SO_2$ as well as molten salt corrosion also had an effect on the total corrosion rate, especially showing an increase in the corrosion rate in ferritic steels. Regardless of the chrome content in the steels and irrespective of the test temperature, the corrosion scale was composed of an outer oxide and an artificial ash mixed layer, a middle oxide layer and inner sulfide, and a mixed oxide layer. As the chrome content increased, the proportion of chrome oxide in the corrosion scale increased. Before spalling of the corrosion scale, voids and cracks were initiated in the sulfide and the mixed oxide layer or at the interface with the substrate.

• Journal of Industrial and Engineering Chemistry
• /
• v.67
• /
• pp.148-155
• /
• 2018

To get a better understanding of the effect of physicochemical properties and microstructure on $SO_2$ absorption behavior of DESs with different molar ratios of EmimCl and EG (from 2:1 to 1:2), densities (${\rho}$), viscosities (${\eta}$), speeds of sound (u), refractive indices ($n_D$), and thermal decomposition temperatures ($T_d$) of EmimCl-EG DESs were measured and used to obtain the other derived properties, such as thermal expansion coefficient (${\alpha}_p$) and activation energy for viscous flow ($E_{\eta}$). Moreover, FT-IR spectra and in situ variable-temperature NMR spectroscopy were employed to study the microstructures of DESs. Based on physicochemical and spectroscopic properties, the influence of the concentrations of EmimCl on the interactions in DESs was explored to be associated with their $SO_2$ absorption behavior. The results show that the interactions between $Emim^+$ and $Cl^-$ of EmimCl is gradually weakening with increasing the concentration of EG in DESs by forming of hydrogen bond interaction of $O-H{\cdots}Cl^-$, resulting in a decrease of ${\rho}$, ${\eta}$, u, $n_D$, and $T_d$ of DESs, and hindering the charge-transfer interaction of $SO_2$ with $Cl^-$ and deceasing $SO_2$ capture capacity. Moreover, the $SO_2$ absorption capacity of DESs is proportional to their ${\rho}$ and $E_{\eta}$, respectively.

• Korean Journal of Agricultural Science
• /
• v.8 no.2
• /
• pp.152-163
• /
• 1981

Changes of ethylene production, photosynthesis, respiration and sulfur content of leaves were investigated in some horticultural plants injured by $SO_2$ exposure. Concurrently the effects of $AgNO_3$, succinic acid- 2, 2-dimethylhydrazide (daminozide) and benomyl spray on reduction of $SO_2$ damage in the plants were examined. 1. The amount of ethylene production was significantly different among species of plants and showed higher and earlier peak at 5 ppm $SO_2$ compared with 2.5 ppm $SO_2$ exposure. 2. $AgNO_3$ sprayed on leaves significantly inhibited ethylene production in Cedrus deodara and Forsythia koreana. And it reduced the defoliation of F. koreana occured by $SO_2$ damage. 3. Photosynthetic rate of Helianthus annuus was decreased markedly after 4 -hr exposures to 5 ppm SO, but it was not reduced during exposure to 2.5 ppm $SO_2$. F. koreana showed a little changes in photosynthetic rate after abrupt reduction at the early stage of $SO_2$ exposure regardless of $SO_2$ concentration. 4. The rate of respiration was increased or decreased markedly in propotion to concentration and hours of $SO_2$ exposure compared with control. Daminozide and benomyl showed a little effects on reduction of respiratory changes occured by $SO_2$ damage in C. deodara and H. annuus but there was no effect when $AgNO_3$ was sprayed on C. deodara. 5. Sulfur content of leaves was increased more rapidly at 5 ppm than at 2.5 ppm $SO_2$ exposure. But the injury in 5 ppm $SO_2$ exposure was found out at low sulfur content compared with 2.5 ppm $SO_2$ exposure.

• Journal of Korean Society of Forest Science
• /
• v.83 no.3
• /
• pp.331-343
• /
• 1994

This study was conducted to find out the effect of $SO_2$ gas on growth of tree species and the effect of pretreatment of ABA to Pinus koraiensis. Abies holophylla and Taeus cuspidata on the susceptibility for $SO_2$ gas damage. The survey was carried out on the water contents of leaf and shoot, and the acidities of bark and leaf, and the chlorophyll and water soluble sulfur contents, and the changes of transpiration rates on selected seedlings exposed to $SO_2$ gas at seven levels : 0ppm, 0.5ppm, 1ppm, 2ppm, 4ppm, 26.4ppm ABA, 56.8ppm ABA. The results obtained from this research are as follows : 1. The water contents of leaf and shoot of the three tree species decreased with increasing concentrations of $SO_2$ gas and the relative susceptibility of Abies holophylla was larger than those of Taxus cuspidata and Pinus koraiensis because moisture diminution rates were higher in leaves and shoots of Abies holophylla than those of other species. 2. The acidities of bark and leaf of the three tree species increased with increasing concentrations of $SO_2$ gas. The relative susceptibility of Pinus koraiensis in bark acidity was larger than those of Abies holopfaylla and Toxus cuspidata. Abies holophylla was more susceptive than Pinus koraiensis and Taxus cuspidata. 3. Water soluble sulfur contents of the three tree species increased with increasing concentration of $SO_2$ gas. The relative susceptibility of Taxus cuspidata in water soluble sulfur contents was lager than those of Pinus koraiensis and Abies holophylla. 4. Leaf chlorophyll contents of the three tree species decreased with increasing concentrations of $SO_2$ gas. The order of the relative susceptibility in leaf chlorophyll contents was Taxus cuspidata, Abies holophylla and Pinus koraiensis. 5. Correlation coefficients among the measurement were highly significant for $SO_2$ treatment in all three tree species. 6. The transpiration rates of Abies holophylla and Taxus cuspidata did not change until up to 220 minutes after initiation of $SO_2$ gas fumigation, and changed a little during the time between 220 minutes and 270 minutes. On the other hand, Pinus koraiensis continued to change in transpiration rates little by little from the start of $SO_2$ gas treatment up to 270 minutes, meaning that Pinus koraiensis is less sensitive to ABA. 7. When 2ppm of $SO_2$ was treated. ABA pretreatment effect was detected on the six measurement parameters. ABA affected the resistance of plants by inducing stomata closure. 8. The order of relative susceptibility of the three tree species to $SO_2$ gas fumigation was Abies holophylla, Taxus cuspidata and Pinus koraiensis. Pinus koraiensis was more resistant to $SO_2$ gas than Abies holophylla and Taxus cuspidata.

• Korean Journal of Remote Sensing
• /
• v.35 no.2
• /
• pp.289-298
• /
• 2019

In this present study, the effects of Signal to Noise Ratio (SNR), Full Width Half Maximum (FWHM), Aerosol Optical Depth (AOD), $O_3$ Vertical Column Density ($O_3$ VCD), and Solar Zenith Angle (SZA) on the accuracy of sulfur dioxide Vertical Column Density ($SO_2$ VCD) retrieval have been quantified using the Differential Optical Absorption Spectroscopy (DOAS) method with the ground-based direct-sun synthetic radiances. The synthetic radiances produced based on the Beer-Lambert-Bouguer law without consideration of the diffuse effect. In the SNR condition of 650 (1300) with FWHM = 0.6 nm, AOD = 0.2, $O_3$ VCD = 300 DU, and $SZA=30^{\circ}$, the Absolute Percentage Difference (APD) between the true $SO_2$ VCD values and those retrieved ranges from 80% (28%) to 16% (5%) for the $SO_2$ VCD of $8.1{\times}10^{15}$ and $2.7{\times}10^{16}molecules\;cm^{-2}$, respectively. For an FWHM of 0.2 nm (1.0 nm) with the $SO_2$ VCD values equal to or greater than $2.7{\times}10^{16}molecules\;cm^{-2}$, the APD ranges from 6.4% (29%) to 6.2% (10%). Additionally, when FWHM, SZA, AOD, and $O_3$ VCD values increase, APDs tend to be large. On the other hand, SNR values increase, APDs are found to decrease. Eventually, it is revealed that the effects of FWHM and SZA on $SO_2$ VCD retrieval accuracy are larger than those of $O_3$ VCD and AOD. The SZA effects on the reduction of $SO_2$ VCD retrieval accuracy is found to be dominant over the that of FWHM for the condition of $SO_2$ VCD larger than $2.7{\times}10^{16}molecules\;cm^{-2}$.

• The Journal of Internal Korean Medicine
• /
• v.31 no.3
• /
• pp.650-666
• /
• 2010

Objectives : In this study, the author tried to investigate whether wood vinegar produced from Morus alba (MA) significantly affects the increase in airway epithelial mucosubstances and hyperplasia of tracheal goblet cells of rats, and in vitro airway mucin secretion and PMA- or EGF- or TNF-alpha-induced MUC5AC mucin production / gene expression from human airway epithelial cells. Materials and Methods : For the in vivo experiment, the author induced hypersecretion of airway mucus and goblet cell hyperplasia by exposure of rats to SO2 over 3 weeks. Effect of orally-administered MA over 2 weeks on increase in airway epithelial mucosubstances from tracheal goblet cells of rats and hyperplasia of goblet cells were assessed using histopathological analysis after staining the epithelial tissue with alcian blue. For the in vitro experiment, confluent RTSE cells were chased for 30 min in the presence of MA to assess the effect of MA on mucin secretion by enzyme-linked immunosorbent assay (ELISA). Also, effects of MA on PMA- or EGF- or TNF-alpha-induced MUC5AC mucin production and gene expression from human airway epithelial cells (NCI-H292) were investigated. Confluent NCI-H292 cells were pretreated for 30 min in the presence of MA and treated with PMA (10 ng/ml), EGF (25 ng/ml) or TNF-alpha (0.2 nm) for 24 hrs, to assess both effects of MA on PMA- or EGF- or TNF-alpha-induced MUC5AC mucin production by enzyme-linked immunosorbent assay (ELISA) and gene expression by reverse transcription-polymerase chain reaction (RT-PCR). Possible cytotoxicities of MA in vitro were assessed by examining LDH release from RTSE cells and the rate of survival and proliferation of NCI-H292 cells. In vivo liver and kidney toxicities of MA were evaluated by measuring serum GOT/GPT activities and serum BUN/creatinine concentrations of rats after administering MA orally. Results : 1. MA decreased the amount of intraepithelial mucosubstances of rats exposed to sulfur dioxide inhalationally. 2. MA decreased in vitro mucin secretion from cultured RTSE cells. 3. MA significantly inhibited PMA-, EGF-, and TNF-alpha-induced MUC5AC mucin productions and the expression levels of MUC5AC mRNA from NCI-H292 cells. 4. MA did not show either in vitro or in vivo hepatic or renal toxicities. Conclusion : The results from this study suggests that MA can regulate the secretion, production and gene expression of airway mucin observed in diverse respiratory diseases accompanied by mucus hypersecretion and does not show in vivo toxicity to liver and kidney functions after oral administration. Effects of MA should be further studied using animal experimental models that simulate the diverse pathophysiology of respiratory diseases via future research.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.4
• /
• pp.277-285
• /
• 2014

The usage of efficient microorganism (EM) is increasing in concern for server purposes including odor removal during carcasses degradation. In this study, we have studied the type of soil and its effect on efficient microorganisms for the removal of odorous gases during buried carcasses degradation in lab-scale reactor. The carcasses are buried in the reactor with various soil types such as normal soil, 20% sandy and 20% clay soil with the efficient microorganism KEM. The efficient microorganisms KEM have the ability to stabilize the degradation of carcasses of the burial site. We have focused on the analysis of odorous gases such tri-methylamine (TMA), hydrogen sulfide ($H_2S$), methyl mercaptan (MM), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), carbon dioxide ($CO_2$), and methane ($CH_4$) along with the changes of microbial community changed during complete degradation of buried carcasses for a year. The results suggested that the 20% sandy soil contain lesser level of $H_2S$ and MM (0.09 and 0.35 mg) but 20% clay has higher nitrogen compound removing effect and leave only less amount of ammonia and TMA (0.31 and 2.06 mg). The 20% sandy soil also has the ability to breakdown the carcasses more quality compared with other types of soil. Based on the data obtained in this study suggesting that, the use of 20% sandy soil can effectively control sulfur compounds whereas 20% clay soil controls nitrogen compounds in the buried soil. Depending on the type of the soil, the dominant of microbial communities and the distribution was change.