• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.367-371
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• 2004

Bio-degradable hydraulic oil using polyolester base oil is formulated for the applications of heavy duty hydraulic machineries. It has proved quality and market price competitiveness by assessment of reliability test in vehicle manufacturer and specific vehicle related institute. Contribution of bio-degradable oil keep the working environment clean and increase export competitiveness in European market. Leakage or waste of mineral types of hydraulic oils in heavy duty machineries causes pollution of river, ocean, underground water. Drinkable-water pollution is serious problem in Europe. In some European countries, using bio-degradable hydraulic oils become an obligation in heavy duty machineries. New product of bio-degradable oils satisfy the European regulations(OECD 302B) and shows excellent performance in compare with European products.

• Journal of the Korean Applied Science and Technology
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• v.21 no.2
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• pp.124-131
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• 2004

The adsorption of heavy metals in the waste water carried out on the various domestic clays and waste pottery. The effect of parameters such as pH, temperature, adsorption time and coexisting cations on the adsorption ability and characteristics were investigated to find out whether the clays could be used as adsorbents. Adsorption equilibrium was reached within 20 minutes on all the clays. The optimum pH was found to be above 5. When other cations such as Cu(II) or Zn(II) coexisted with Pb(II), the adsorption amount of Pb(II) decreased because of competing adsorption.

• Journal of environmental and Sanitary engineering
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• v.12 no.1
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• pp.97-100
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• 1997

The adsorption of the Chchory particles on Cu(II), Pb(II) and Cd(II) ions were examined by measurements of the adsorption percentage under various condition of temperature, pH, times, heavy metal concentration. Each of 100ml sample solution of Cu(II), Pb(II) and Cd(II) ions mixed with 2g of the Cichory under stirring in shaking water bath for minutes. The solutions were then filtered and pretreatmented according to water pollution official test methods. The concentrations of Cu(II), Pb(II) and Cd(II) ions in the solution were determined by the atomic adsorption spectrophotometer. As a results, the most effective pH of the adsorption of Cu(II), Pb(II) and Cd(II) was 9. With increasing the concentration of heavy metals the amount of adsorption on Cichory was increased. The adsorption equilibrium of Pb(II) and Cd(II) ions were reached to equilibrium by shaking for about 40 minutes. The absorptivities were 85%, 75% respectively.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.407-414
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• 2008

This study was conducted to evaluate the heavy metal contamination in the soils of Maehyang-ri inland shooting range area. The texture of the Maehyang-ri inland shooting range soil was sandy. Extraction of heavy metals reached quasi-equilibrium within 6 hours using shaking with 0.1 N HCl. 95% and 94% of extraction efficiency was observed for Cu and Pb in the Maehyang-ri shooting range soils, respectively. And Cu and Pb contamination of level of the T-1 region soil was $114.4{\pm}5.7mg/kg$ and $362.3{\pm}20.5mg/kg$. This may be due to the effects of mineralogical factor, soil particle size and un-residual fractions such as exchangeable, carbonate, Fe-Mn oxide and organic+sulfide.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3788-3792
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• 2012

Spherical-shape melanin nanoparticles with good water-dispersibility were successfully synthesized by a simple oxidation polymerization of 3,4-dihydroxy-phenylalanin (DOPA) with $KMnO_4$. Similar features to those known from natural and synthetic melanin polymers were observed from prepared melanin nanoparticles by FT-IR, UV-Vis., and ESR spectroscopic methods. Their binding ability with several heavy metal ions from aqueous solution was quantitatively investigated, and the maximum binding capacities with melanin nanoparticles to lead, copper, and cadmium ions were obtained as 2.45, 2.17 and 1.88 mmol/g, respectively, which are much larger values than those reported from natural and synthetic melanin polymers. The large binding capacity and fast binding rate of melanin nanoparticles to metal ions can make them an excellent candidate for the remediation of contaminated water.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.170-170
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• 2018

In some case studies, the heavy precipitation events and rapid cyclogenesis in the extratropics can be caused by moist and warm tropical air masses. Tropical Moisture Exports (TME) correspond to the meridional transport of moist air masses, primarily born in tropical oceanic areas, to higher latitudes; and are closely related to flood events, especially in the mid-latitudes. The TME for the region of interest is mostly estimated by the back tracking approach using Lagrangian Analysis Tools (LAGRANTO) from ECMWF Re-Analysis (ERA) data. In this study, we aim to estimate the TME that are related to rainfall in Korea. The major moisture sources of the TME that contribute to heavy rainfall and extreme floods in Korea are identified. The TME is found to have significant connection with extreme events in Korea such as heavy rainfall and extreme flood events. The results show the most of the moisture sources comes from the west Pacific during the warm half of the year and it contributes significantly to the annual TME and is linked to the East Asian monsoon.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.740-744
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• 1994

This study was undertaken to prove the suppressing effect of green tea on the intestinal absorption of heavy metals using in vitro membrane filtration system. From drinking water contaminated with 10 and 100 times level of water quality standard for heavy metals, the removal ratio of lead (Pb) was $50{\sim}70%$ by green and black teas, and $30{\sim}40%$ by roasted barley tea. The removal ratio of cadmium (Cd) was $30{\sim}40%$ by green tea and black teas, and $10{\sim}20%$ by roasted barley tea. The removal effect from drinking water contaminated with both lead and cadmium was lower than that from water contaminated singly with lead or cadmium. It appears that tea components and filter membrane compete toward the adsorption of two heavy metals. Among the extraction conditions of raw tea materials at $70^{\circ}C$, 2 minutes and $95^{\circ}C$ , 10 minutes, the removal ratios of heavy metals were similar.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.53-59
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• 2014

In this study, the sewage sludge dryer is installed before and after dehydration of the sludge and aqueous phase composition, the heavy metal content, and measurement and analysis were investigated. The removal efficiency of water content of sewage sludge was about 95.7% in the sewage sludge dryer. The removal efficiency of water content for primary dryer was designed for 35% of primary drying, secondary drying to remove the water content to 10%, but as the measurement revealed that 20.8% of primary drying, the second dryer 3.3% a better effect to the actual operation respectively. Before the installation of the sewage sludge dryer, the content of heavy metal was as follows, Cu:352~614 ppm, Hg: 1.3~1.44ppm, Cd : 1.1~1.86ppm, Pb : 17.25~ 28.93 ppm, As : 1ppm. And after the installation of the sewage sludge dryer, the content of heavy metal changed to as follows, Cu : 340~350 ppm, Hg : 0 ppm, Cd : 0~0.021 ppm, Pb : 0 ppm, As : 0~0.043 ppm which is Also below the legal limits. Also, the sewage sludge dryer produce 1/4 of the sewage sludge into dried sludge.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.43-49
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• 2006

The hull form of icebreaking tanker depends on the trade route and ice characteristic. The hull form has to be designed for icebreaking concept if the vessel is operating in heavy ice and also the hull from has to be optimized for general tanker when the ship is operating in ice-free ocean. This paper presents comparison of ship resistance in pack ice, level ice and open water. Four ships are used to compare the resistance characteristic. One is conventional tanker and three ships are icebreaking tankers. The ice model test was carried out at the IOT (Institute for Ocean Technology, Newfoundland, Canada) and open water test was performed at 55MB (Samsung Ship Model Basin). The ice resistance of conventional tanker was predicted by Colbourne's method. The resistance of open water, pack ice and level ice are compared and discussed. The best hull form of icebreaker is not good in open water performance compare to conventional tanker. This result explains that the hull form of icebreaker and normal tanker have to compromise when the ship is operated in ice and ice-free condition. The result of this paper gives a guide for icebreaking tanker design.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.210-217
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• 2007