• Journal of the Korean Society for Heat Treatment
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• v.35 no.4
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• pp.193-202
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• 2022

Manholes and underground spaces are installed to manage the buried heat transport pipes of the district heating system, and the corrosion damage of the equipment placed in this space often occurs. The purpose of this work is to identify locations with a high risk of corrosion damage in the air vent and to establish preventive measures based on precise analysis via sampling of heat transport pipes and air vents that have been used for about 30 years. The residual thickness of the air vent decreased significantly by reaching ~1.1 mm in thickness, and locations of 60~70 mm away from a transport pipe were the most vulnerable to corrosion. The energy dispersive X-ray spectroscopy (EDS) analysis was performed in the corroded oxides, and it was found that chloride ion was contained in the corrosion products. Anodic polarization tests were carried out on the air vent materials (SPPS250, SS304) with varying the amounts of chloride ions at two different temperatures (RT, 80℃). The higher concentration of chloride ions and temperature are, the lower corrosion resistances of both alloys are.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.578-581
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• 2006

This study was performed to develop acid-soluble extraction solution and water-soluble extraction solution for hardened concrete. By use of this potentiometric method one can determinate chloride ion concentration in hardened concrete without pre-treatment and it can be used on-site.

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.20-22
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• 1992

Treatment of benzal chloride, alcohol, $K_2CO_3$, and a catalytic amount of $Co_2(CO)_8$ at $80^{\circ}C$ for 24 hours under 30 atm of CO gave the corresponding alkyl phenylacetate in good yield.

• Environmental Engineering Research
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• v.9 no.6
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• pp.279-287
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• 2004

• Korean Journal of Oriental Medicine
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• v.13 no.2 s.20
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• pp.157-164
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• 2007

An imbalance in bone remodeling that is caused by increased bone resorption over bone formation leads to most adult skeletal diseases including osteoporosis. Since the development of anti-resorptive agents from natural substances has recently gained more interest in the treatment of osteoporosis, we evaluated the effects of 222 natural compounds on receptor activator of $NF-{\kappa}B$ ligand (RANKL)-induced of tartrate-resistance acid phosphatase (TRAP) activity in RAW264.7 murine macrophage cell, and found that berberine chloride is one of compounds inhibiting RANKL-induced TRAP activity. Berberine chloride significantly inhibited the RANKL-induced TRAP activity and the formation of multinucleated osteoclasts in a dose-dependent manner. In addition, berberine chloride prevented the RANKL-induced mRNA expression of TRAP, matrix metalloproteinase 9 and c-Src, which have been known to be highly expressed in the process of osteoclastogenesis. Interestingly, berberine chloride prevented the RANKL-induced activation of extracellular signal-regulated kinase (ERK) which is one of mitogen-activated protein (MAP) kinases. In conclusion, berberine chloride could inhibit the osteoclastogenesis via preventing the activation of ERK/MAP kinase signaling pathway.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.39-46
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• 2009

A method to improve water treatment efficiency by coagulant overdosing for high pH raw water at a drinking water treatment plant (WTP) which had no pH adjusting facilities was investigated. Poly aluminum chloride (PACl) was used for coagulant, and turbidity removal efficiency was evaluated as a function of PACl dosage increases. pH and turbidity of supernatant of jar-tester were 7.10 and 0.50 NTU respectively, when the turbidity, pH, alkalinity, water temperature, conductivity of raw water were 1.75 NTU, 9.38, 46.5 mg/L, $6.4^{\circ}C$, $400{\mu}s/cm$, respectively. Turbidity of settled water was reduced from 2.18 NTU to 0.28 NTU (87% reduction) when PACl dosage was increased from 16 mg/L to 45 mg/L at a full scale WTP. This can be attributed to the recovery of coagulant efficiency by pH reduction with the increase of coagulant dose, however coagulation efficiency was reduced with the formation of Al(OH)4- by PACl addition at higher pH. Coagulant overdosing was proven to be a rapid and effective method for high pH raw water, which can be applied at drinking WTP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.493-498
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• 2013

The production of synthetic polymer compounds and ethanolamine (ETA, a pH control agent used in nuclear power plants) generates effluent that pollutes water. This study focused on the development of chemicals for the treatment of effluent and processes to reduce the COD level due to the presence of organic materials via physicochemical treatment. It was found that a mixed coagulant of $FeCl_2$ and $MgCl_2$ (1:1) was the most effective in treating effluent and reducing the COD level. When the mixed coagulant was injected into effluent including organic materials, the COD level was reduced by more than 80%.

• Journal of the Korea Concrete Institute
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• v.26 no.1
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• pp.71-78
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• 2014

The long term integrity of concrete cask is very important for spent nuclear fuel dry storage system. However, there are serious concerns about early deterioration of concrete cask from creaking and corrosion of reinforcing steel by chloride ion because the cask is usually located in seaside, expecially by combined deterioration such as chloride ion and heat, carbonation. This study is to investigate the relation between temperature and chloride ion diffusion of concrete. Immersion tests using 3.5% NaCl solution that were controlled in four level of temperature, i.e. 20, 40, 65, and $90^{\circ}C$, were conducted for four months. The chloride ion diffusion coefficient of concrete was predicted based on the results of profiles of Cl- ion concentration with the depth direction of concrete specimens using the method of potentiometric titration by $AgNO_3$. Test results indicate that the diffusion coefficient of chloride ion increases remarkably with increasing temperature, and there was a linear relation between the natural logarithm values of the diffusion coefficients and the reciprocal of the temperature from the Arrhenius plots. Activation energy of concrete in this study was about 46.6 (W/C = 40%), 41.7 (W/C = 50%), 30.7 (W/C = 60%) kJ/mol under a temperature of up to $90^{\circ}C$, and concrete with lower water-cement ratio has a tendency towards having higher temperature dependency.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.19-23
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• 1998

This study has designed to investigate the removal effect of sewage treatment effluent by ultrafilter membrane species and then to analyze the change of pH, bacteria and E. coli., the concentration of chlorides. Ultra filtration process did not effective to remove chloride, Ca and Mg. Spiral type ultrafiltration process was more effective to remove chemical oxygen demand of sewage treatment effluent than Hollow type ultrafiltration process. The flux of spiral wound ultrafilter was higher than the hollow fiber ultrafilter.

• Journal of Sericultural and Entomological Science
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• v.43 no.1
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• pp.37-40
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• 2001

This study was carried out to investigate the optimum condition for silk sericin collection from degumming solution using some aluminium salts with various treatment conditions and examine the thermal properties of silk sericin collected from degumming solution. Silk sericin was precipitated by treatment of aluminium metal compound from degumming solution. The best optimum collecting conditions of silk sericin from degumming solution are the concentration of 2 $m\ell$/l of polyaluminium chloride (PAC), pH range of 5~7 and room temperature. The reduction of water pollution was evaluated by decreasing the chemical oxygen demand (COD) and nitrate ion (NO$_3$￣). Thermal stability of silk sericin collected from degumming solution was a little lower than that of hot water.