• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.307-312
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• 2007

Seawater intrusion in estuarine regions is an important issue in protecting groundwater against salinity increase as well as in protecting construction materials against corrosion. For example, drain water ejected during accelerated consolidation for the improvement of soft ground can cause damages to farm land because the drain water from seawater intrusion zones contains salinity. In this study, we have employed correlation analysis between resistivity value and salinity of in situ pore water. The correlation analysis indicates that resistivity and salinity are in exponential relationship with good correlation. Therefore we suggest that rapid estimation of spatial distribution of NaCl is possible using resistivity data.

• Corrosion Science and Technology
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• v.8 no.4
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• pp.148-152
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• 2009

The failure of a Zn-plated carbon steel pipe that served as a fire sprinkler was investigated in terms of the pipe's corrosion products. The pipes leaked through holes formed beneath the tubercles. The formation of oxygen concentration cell involves colonization of metal surface by aerobic bacteria or other slime formers, and anodic reaction beneath tubercle is accelerated by the presence of SRB, leading to the formation of hole beneath tubercle.

• Journal of Drive and Control
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• v.14 no.1
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• pp.29-34
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• 2017

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.196-200
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• 1996

In the case of construction under the marine environment the durability of concrete structures is everely deteriorated by the penetration of salts which results in the corrosion of reinforcing steel. To verify the effect of corrosion protection of reinforcing steel by isolating the penetration of chlorideion this study investigated the bond strength between painting material and concrete, the degree of the penetration-diffusion of chloride ion and the accelerated corrosion test using different potential. Results show that the painted concrete has little the penetration-diffusion of cholride and the reinforcing steel in painted concrete is little corroding.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.191-196
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• 1997

Steel is the most used as materials for construction and corrosion expansion of steel due to outdoor corrosive environmental factor bring serious problem on the durability of concrete structures time after time. It is the purpose of this study to see whether it is effective of not, when sacrificial anode method is adapted. Indoor accelerated corrosion testing was carried out to see its effective in a short term. From the mid result, potential of steel in concrete in case of adapting sacrifice anode method satisfacts protection standard value (less than-850mV vs CSE), therefore sacrificial anode method is considered as a proper protection steps against corrosion of steel.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.441-444
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• 2005

Our country has experienced variations in temperature as belong to the area of the continental climate that shows four significant seasons. These occur immense difficulty on the period, cost, quality of construction. As the hydration of cement processes, the strength of concrete is developed. In order to improve the quality of concrete, various conditions including temperature and humidity should be maintained appropriately and concrete itself should be cured sufficiently. In the early age, the strength of concrete is developed remarkably. However, the hydration is accelerated too much in high temperature or delayed too much in low temperature, so the quality can be changed and It can fail to get the objective strength. This paper aims to offer the data, necessary to the quality control handbook.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.221-224
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• 2004

Several factors of concrete durability decline factor are acted as complex deterioration and is happened not that happen by simplicity deterioration. Specially, in case of sea construction, as complex salt damage, carbonation and freezing & thawing, concrete surface and pore structure is deteriorated. Therefore, analyzing concrete carbonation and pore structure after freezing and thawing test by fresh water and sea water in this research, we wish to study about acceleration of decline of durability and complex deterioration by concrete surface deterioration in sea environment.

• Proceedings of the KIEE Conference
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• summer
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• pp.950-952
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• 2004

The developments of small hydropower plants in korea have been delayed by rising construction cost/low feasibility, local people's disagreement even though the capacity of water resources are enough. However, the recent raising of electricity purchasing price, the government's enlarging plan of small hydropower plants caused the newly development to be accelerated. In this paper, the design of remote control of small hydropower plants are proposed for better economy and easy control. The operation and monitoring of power plants are planned based on One(1)-man control from the central control room of regional area water works/ operating station and engineering station multipurpose dam offices with the equipments of OS, RTU(PLC), KT leased lines, WMPS, CSU and etc.

• New & Renewable Energy
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• v.9 no.1
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• pp.6-11
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• 2013

Jeollabuk-do has announced a future plan for the Saemangeum Wind Farm which includes the installation of fourteen wind turbines in a single line, located 500m back from the Saemangeum Seawall. It is anticipated as a positive effect that, for sea breeze blowing toward land, the average wind speed could be accelerated and the wind speed distribution could be uniformized by dint of the seawall, an upstream structure of the turbines. At the same time it is also anticipated as a negative effect that the strength of wind turbulence could be increased due to the flow separation generated at the back end of the seawall. According to the results of the computational fluid dynamics analysis of this paper, it has been observed that, at the 50m zone on the road surface located at the uppermost part of the Saemangeum Seawall, the average wind speed has been accelerated by approximately 6~7% and that wind shear has been decreased by 70%, but this positive effect disappears in the zone situated beyond the 100m from the back end of the seawall. It has also been observed that flow separation exists to a limited extent only below the bottom of the blade-sweeping circle and, furthermore, does not extend very far downstream of the wind. As a conclusion, it can be said that the seawall neither positively nor negatively affects the proposed Saemangeum Seawall Wind Farm layout.

• International Journal of Highway Engineering
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• v.7 no.3 s.25
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• pp.93-100
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• 2005

Rock produced in situ has been used as the road construction materials in consideration of economies. However, because sedimentary rock is rapidly weathered, it is hard to decide appropriateness of quality specifications. This study aims at evaluation of usability for sub-base of muddy stone produced in situ. Test results show that the abrasion ratio is fitted for specifications, but weight loss in 37.5$\sim$16mm after Los Angeles abrasion test shows 47% in muddy stone in comparison with 20$\sim$30% in gneiss and sandstone. The soundness of aggregate shows higher value in muddy stone than in gneiss and sandstone. The weight loss from accelerated weathering test due to freezing and drying show 58% in muddy stone in comparison with 308$\sim$21% gneiss and sandstone.