• Journal of Environmental Science International
• /
• v.12 no.5
• /
• pp.541-549
• /
• 2003

Aerosol measurement were carried out to investigate the characteristics of its chemical composition directly affected by the local emissions of Jeju City, Jeju Island by using an eight-stage cascade impactor from Dec. 1999 to Aug. 2000. The ambient aerosol concentrations measured at Jeju City were generally very low but the fine particle concentrations were to be higher than the US standard of PM2.5. The majority of sulfate were non sea salt and contained in the fine particles. In the fine particles, the concentrations of Na$\^$+/, K$\^$+/, Mg$\^$2+/, Ca$\^$2+/, Cl$\^$-/ and NO$\sub$3$\^$-/ had a tendency to increase during the springtime rather than the other seasons. However, the springtime sulfate and ammonium concentrations in the fine particles were slightly lower than those during the other seasons. On the other hand, associated with the coarse particles, the concentrations of ionic species except potassium and ammonium were elevated during the springtime. The calcium concentrations in the coarse particles were increased up to 8 times relative to the other seasons.

• Resources Recycling
• /
• v.14 no.2
• /
• pp.10-18
• /
• 2005

The manufacture property of anhydrous calcium sulfate (anhydrite Ⅱ) from flue gas desulfurization (FGD) gypsum discharged from domestic thermoelectric power plants to apply as an auxiliary material of cement and concrete by high temperature treatment were investigated. The FGD gypsum was completely converted to anhydrite Ⅱ at the temperature of 700$^{\circ}C$ and the retention time of 1 hr. In the phase transformation process, particle size was also changed. The chemical composition, particle size and heat property of anhydrite Ⅱ made from the FGD gypsum were similar to them of natural gypsum. In the leaching test of sulfate ion (SO$_4^{2-}$) at the temperature of 90$^{\circ}C$ and the retention time of 1 hr, the amount of leached SO$_4^{2-}$ for the anhydrite Ⅱ that was sintered at 700$^{\circ}C$ for 1 hr was about 50 wt.% based on that of natural gypsum. In addition, the amount of leached SO$_4^{2-}$ for the anhydrite Ⅱ by adding the slaked lime of 3 wt.% decreased about 70 wt.% comparing with that of natural gypsum. In the application test, the compressive strength of cement and concrete manufactured by using the anhydrite Ⅱ as an auxiliary material were similar or superior compared with them of cement and concrete done by natural gypsum as an auxiliary material.

• Mycobiology
• /
• v.42 no.1
• /
• pp.59-65
• /
• 2014

Entomopathogenic fungi are promising pest-control agents but their industrial applicability is limited by their thermosusceptibility. With an aim to increase the thermotolerance of Isaria fumosorosea SFP-198, moisture absorbents were added to dried conidial powder, and the relationship between its water potential and thermotolerance was investigated. Mycotized rice grains were dried at $10^{\circ}C$, $20^{\circ}C$, $30^{\circ}C$, and $40^{\circ}C$ and the drying effect of each temperature for 24, 48, 96, and 140 hr was determined. Drying for 48 hr at $10^{\circ}C$ and $20^{\circ}C$ reduced the moisture content to < 5% without any significant loss of conidial thermotolerance, but drying at $30^{\circ}C$ and $40^{\circ}C$ reduced both moisture content and conidial thermotolerance. To maintain thermotolerance during storage, moisture absorbents, such as calcium chloride, silica gel, magnesium sulfate, white carbon, and sodium sulfate were individually added to previously dried-conidial powder at 10% (w/w). These mixtures was then stored at room temperature for 30 days and subjected to $50^{\circ}C$ for 2 hr. The white carbon mixture had the highest conidial thermotolerance, followed by silica gel, magnesium sulfate, and then the other absorbents. A significant correlation between the water potential and conidial thermotolerance was observed in all conidia-absorbent mixtures tested in this study (r = -0.945). Conidial thermotolerance in wet conditions was evaluated by adding moisturized white carbon (0~20% $H_2O$) to conidia to mimic wet conditions. Notably, the conidia still maintained their thermotolerance under these conditions. Thus, it is evident that conidial thermotolerance can be maintained by drying mycotized rice grains at low temperatures and adding a moisture absorbent, such as white carbon.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.1
• /
• pp.149-157
• /
• 2012

Experiments for As(V) removal using synthesized $Ca{\cdot}Al$-monosulfate was performed from the water contaminated with arsenate. Monosulfate is known as LDHs (Layered Double Hydroxides) which is one of the anionic clay minerals. Monosulfate was synthesized mixing $C_3A$ (tricalcium aluminate), gypsum (calcium sulfate), and water with an intercalation method. The product form the synthesis was characterized by FE-SEM, WDXRF, PXRD, and FT-IR. Experiments with different doses of monosulfate were carried out for kinetic. As a result of experiment, the concentration of As(V) was reduced from 0.67 mM to 0.19 mM (0.67mM of monosulfate) and 0.178 mM (1.34 mM of monosulfate). The concentration of sulfate was increased with As(V) decrease. The result of PXRD showed that the d-spacing of inter layer ($d_{003}$ peak) was shifted from 8.927 ${\AA}$ to 8.095 ${\AA}$ because the sulfate in the inter layer of monosulfate was exchanged arsenate with water molecules bonded. From the FT-IR results, a new single band (800 cm-1) was observed after the reaction of monosulfate and As(V). The arsenic removal can be regarded as anion exchange mechanism that is one of the characteristics of LDHs from the results of PXRD and FT-IR analysis.

• Korean Journal of Soil Science and Fertilizer
• /
• v.16 no.1
• /
• pp.36-41
• /
• 1983

These studies were carried out to investigate the effects of potassium salts on the changes of chemical properties in submerged soil. Rice plants were cultured in submerged soil using potassium salts. Obtained results were as follows. In the submerged soil cultured with rice plants the value of pH was higher in the potassium chloride plot than in the potassium sulfate plot. The leaching of cations such as calcium, magnesium, potassium and ammonium were higher in the potassium chloride plot than in the potassium sulfate plot. On the other hand, the leaching of phosphate ion was slightly higher in the potassium sulfate plot than in the potassium chloride plot. The leaching of iron was higher in the planted plot than in the non-planted plot, but that of silica was higher in the non-planted plot than in the planted plot. However, the leaching of iron and silica was not affected by potassium salts.

• Korean Journal of Food Science and Technology
• /
• v.54 no.1
• /
• pp.75-79
• /
• 2022

Fresh, washed ginseng can be contaminated with microorganism loads as high as 6.5 log CFU/g for total bacteria and 4.3 log CFU/g for mold. The goal of this study was to test eight antibacterial agents on ginseng. Immersing fresh ginseng washed in 1% (w/w) sodium citrate, sodium diacetate, sodium acetate, citric acid, and sodium lactate solution for 1 h resulted in a bactericidal effect of 31.0-97.5% for total bacteria. Among the organic acids, sodium citrate had the best antibacterial effect, with total bacteria reduced from 6.5 log to 4.9 log CFU/g. A 1% (w/w) vitamin B₁ lauryl sulfate solution with surfactant function by hydrophilic and hydrophobic sites can reduce 2.7 log CFU/g (99.8% inactivation) on total bacteria. In the 1% (w/w) calcium oxide solution, total bacteria were reduced by 3 log, showing an excellent inactivation effect of 99.9%. Calcium oxide is a highly useful material for inactivation of microorganisms in fresh ginseng.

• Journal of Environmental Science International
• /
• v.24 no.5
• /
• pp.615-622
• /
• 2015

East Asia is characterized by anthropogenic emissions resulting from the large population and fast economic growth of this region. Since the prevailing wind is westerly and northwesterly, emissions from Ul-jin can be expected to contribute to acidic deposition increase in downwind direction. Aerosols collected at the near coast site, Uljin geun, gyungbook and were analyzed for $NH_4{^+}$, $Mg^{2+}$, $Na^+$, $Ca^{2+}$, $Cl^-$, $SO_4{^{2-}}$, and $NO_3{^-}$ from Aug. 2012 to Feb. 2013. The seasonal averaged aerosol concentration showed the highest potassium and calcium ion in winter and the highest ammonium ion due to a meadow and high solar intensity in summer. Sodium and chloride ion showed the same ratio all seasons and sulfate and nitrate species showed the maximum value in winter Chemical components of aerosols collected at the near coast site, Uljin geun, gyungbook were lower by 16 to 73% than those collected at other similar environment site such as kanghwa, yangyang. Comparing air quality data at the near coast site, Uljin geun, gyungbook, There was found that Uljin coast site is less influenced by the sea salts(potassium, magnesium, calcium) and nss-$SO_4{^{2-}}$ percentage is 3~13% higher than similar condition site.

• Journal of Mushroom
• /
• v.2 no.4
• /
• pp.214-217
• /
• 2004

This study was carried out to investigate the physiological charateristics of F. pinicola in sawdust media. The optimum temperature in sawdust media was $30^{\circ}C$ in of F. pinicola. The optimum pH was 5 in F. pinicola. Mycelial growth and density of F. pinicola was quite good when birch tree and oak sawdust, respectively were used as cultural substrates. The best mycelial growth in F. pinicola was observed when beer waste was added as supplement on sawdust substrates. The optimum supplement ratios of beer waste and a magnecium sulfate were 20%, and 0.1% respectively. However, optimun supplement ratios of a calcium oxide and a LVD were different as 0.1% in F. pinicola.

• Korean Journal of Agricultural Science
• /
• v.46 no.1
• /
• pp.103-111
• /
• 2019

Gray mold caused by Botrytis cinerea on strawberry plants is an economically significant disease in Korea. The rates for diseased fruits are high during the strawberry harvesting period from December to February, especially in hydroponic cultivation. This study assessed the effect of the nitrogen type in the soil culture and the electrical conductivity (EC) of the nutrient solution in a hydroponic culture on the gray mold incidence in 'Seolhyang' strawberry plants. The nitrogen sources assayed included calcium nitrate tetrahydrate (CN4), calcium nitrate decahydrate (CN10), ammonium sulfate (AS), and commercial fertilizer 213 (213). The effect of the EC was tested at 0.5, 0.8, 1.0, and $1.5dS{\cdot}m^{-1}$. The occurrence of gray mold varied according to the nitrogen type. The disease incidence and nitrogen content for the main nitrogen type were higher compared to the non-treated control. The AS treatment showed the highest occurrence of tipburn and gray mold. The incidence of gray mold as well as the nitrogen and phosphorus content of the leaves increased as the EC level was increased. These results indicate that the incidence of gray mold in strawberry plants is related to the nitrogen content of the leaf and the EC of the nutrient solution.

• Advances in concrete construction
• /
• v.15 no.1
• /
• pp.11-22
• /
• 2023

Autogenous healing of concrete can be helpful in structural maintenance by healing cracks using a healing material created by the precipitation of calcite and by the hydration of unhydrated binder around the cracks. Against this backdrop, this study investigated the physicochemical properties and autogenous healing performance of ternary blended binder composed of ordinary Portland cement (OPC), blast furnace slag (BFS), and calcium sulfoaluminate (CSA) clinker. Ternary blended binders with various contents of OPC-BFS-CSA clinker were prepared, and their physicochemical properties and autogenous healing performances were examined using various analytical techniques and visually observed using a microscope. The obtained results indicated that increase in the BFS content accompanied the increased the amount of unreacted BFS even after 28 days of curing and had a positive effect on the autogenous healing performance due to its latent hydration. However, replacing the CSA clinker did not increase the autogenous healing performance owing to an insufficient sulfate source for the formation of ettringite. The main precipitates around the cracks were calcite, C-S-H. Other hydration products such as portlandite, monosulfate, and ettringite, which were not found in the Raman and scanning electron microscope analyses.