• 전기의세계
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• v.29 no.8
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• pp.532-537
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• 1980

Effect of Argon and Sulfur hexafloride in the transformer oil are experimented under non-uniform A.C. electric field. The result has shown that the corona frequency and corona charge quantity in liquid dielectrics were varied with gas condition in the oil and affected by the additives. SF$_{6}$ that has the effects of pressure and electrical negative characteristic is the most effective. The corona is considered to be the breakdown of bubble produced by gas contained in the oil or by dissociated ion of the oil molecules.s.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1137-1138
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• 2013

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.3 no.1
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• pp.1-7
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• 2000

A new alternative for large deepwater field development is described. This "Oil Box" (aka "Box Spar") is a multifunction vessel capable of floating drilling, production, storage and offloading (FDPSO). It is distinguished from other Floating Production, Storage and Offloading (FPSO) vessels by its unique hull form and oil storage system. It's main advantages are flexibility derived from the floatover deck option, use of proven top tensioned riser technology, and motion characteristics which make it operable in a wide range of environmental conditions.

• Tribology and Lubricants
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• v.20 no.1
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• pp.33-40
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• 2004

This study represents the newly advanced formulation of hydraulic fluids for extended drain interval and introduces the performance results of used oil samples from various excavators. The used oil samples, in this paper, show that there is a sharp change in viscosity drop and moderate additive depletion when viscosity index of hydraulic oil is very high. For the extension of hydraulic fluid life, it is necessary to improve the stability of viscosity and oxidation. New target properties from the used oil analysis were proposed for extended life. Performance of newly developed hydraulic oil based on used oil analysis is compared with previously used one. The properties of new formulation are the viscosity index of 140 and improved thermal stability consists of VHVI base oil. Field test results showed the possibility of extension of fluid life. Additionally, for development of high performance product, new required propertied and performances were discussed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.2
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• pp.67-72
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• 2004

Electro-Rheological(ER) fluids consist of suspensions of fine polarizable particles In a dielectric oil, which upon application of an external electric field control take on the characteristics of the Bingham solid. In this study, the temperature dependence of the viscosity was Investigated for an ER fluid consisting of 35 weight % of zeolite particles in hydraulic oil 46cSt. Thermal activation analysis was performed by changing the ER fluid's temperature from $-10^{\circ}C$ to $50^{\circ}C$. According to the analysis, the activation energy for flow of the ER fluid was 79.6 kJ/mole without applying electric field. On the other hand, with the electric field of 2kV/mm, the linearity between viscosity and temperature was not existed By changing the temperatures the viscosity (or shear stress) versus shear rates were measured. In this experiment shear rates were increased from 0 to $200s^{-1}$ in 2 minutes. Generally, the hydraulic oil 46cSt will be operated at the temperature of about $40^{\circ}C$, thus, the ER fluid's electric field dependence of viscosity was examined at this temperature. Also, an influence of adding the dispersant(Carbopl 940) on ER effect was discussed.

• Membrane Journal
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• v.12 no.4
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• pp.216-225
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• 2002

Experimental study on the crossflow electro-microfi1tation of simulated oil emulsion waste water was carried out with polypropylene microfiltration membrane to evaluate the applicability of electrofiltration process in the treatment of oily waste water generated from many industries including nuclear field. The effects of electric field strength transmembrane pressure, crossflow velocity, and oil emulsion concentration on the permeate flux were investigated. In electro-microfiltration process using the external electric field, significant enhancement of permeate flux was achieved by diminishing membrane fouling and it was shown that considerable permeate flux can be maintained for long-term operation compared with conventional membrane filtration process without an electric field.

• Ocean Systems Engineering
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• v.6 no.3
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• pp.289-303
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• 2016

With more than 100 years exploration and development of offshore oil, more and more offshore oil fields will gradually lose the economic profit to operate. In this article, to take the target oil field for example, the procedure of decommissioning for FPSO, TCMS, subsea system and well abandonment have been analyzed. Meanwhile, the environment impact and mitigation measure have been proposed. The successful project experience will provide a guide line for the offshore facilities decommissioning and abandonment.

• Tunnel and Underground Space
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• v.8 no.2
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• pp.79-86
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• 1998

This study was performed to suggest to suggest suitable design conditions of water curtain system through analysis on pressure down in boreholes by hydraulic tests carried out I construction fields for underground oil storages. The influence by hydraulic conductivities of rock mass around boreholes on pressure down in boreholes was analysed. The relationship between array of boreholes and their pressure down was also analysed. Groundwater flow analysis on crude oil and LPG storages was carried out to evaluate results of field tests and to investigate distribution of hydraulic gradient in rock mass around cavern using finite difference method. As the results, hydraulic tests showed that pressure down in boreholes was inverse proportional to the hydraulic conductivity of surrounding rock mass. The rate of pressure down of boreholes was not influenced by water curtain system more than 20m over cavern and was proportional to installation interval of boreholes. The hydraulic gradient in rock mass around cavern was proportional to distance and interval of boreholes and its value was not satisfactory to oil tightness condition in case of no water curtain system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.53-55
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• 2014

Offshore 에서의 oil & gas 생산은 해상이라는 환경으로 인한 고유의 특성 때문에 항상 다수의 변수들에 영향을 받으며, 막대한 비용이 소요되기 때문에 비용을 최소화하며, 비용 대비 수익을 최대화시키기 위한 optimal design이 필수이다. 본 논문은 가상의 offshore plant와 이에서 생산된 oil의 수요지들을 설정하여 시장수요에 따른 offshore 생산의 최적화 문제를 연구대상으로 하며, 다수의 offshore oil fields를 보유한 major oil company가 당면할 수 있는 offshore production에 관한 문제를 일반화하여 정의하고, 이윤을 극대화시킬 수 있는 최적화 모형을 혼합정수계획모형(mixed integer programming)으로 정식화 하였다. 최적화 모형의 해는 Microsoft office excel solver를 통해 구하였으며 그 계산실험의 결과를 요약하여 보고한다.

• Journal of Soil and Groundwater Environment
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• v.21 no.1
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• pp.72-79
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• 2016

Bioremediation is one of the most effective ways to remediate TPH-contaminated sites. However, under actual field conditions that are not at the optimum temperature, degradation of microorganisms is generally reduced, which is why the efficiency of biodegradation is known to be significantly affected by the soil temperature. Therefore, in this study, the labscale experiment was conducted using indigenous crude oil degrading microorganisms isolated from crude oil contaminated site to evaluate the remediation efficiency. Crude oil degrading microorganisms were isolated from crude oil contaminated soil and temperature, which is a significant factor affecting the remediation efficiency of land farming, was adjusted to evaluate the microbial crude oil degrading ability, degradation time, and remediation efficiency. In order to assess the field applicability, the remediation efficiency was evaluated using crude oil contaminated soil (average TPH concentration of 10,000 mg/kg or more) from the OO premises. Followed by the application of microorganisms at 30℃, the bioremediation process reduced its initial TPH concentration of 10,812 mg/kg down to 1,890 mg/kg in 56 days, which was about an 83% remediation efficiency. By analyzing the correlation among the total number of cells, the number of effective cells, and TPH concentration, it was found that the number of effective microorganisms drastically increased during the period from 10 to 20 days while there was a sharp decrease in TPH concentration. Therefore, we confirmed the applicability of land farming with isolated microorganisms consortium to crude oil contaminated site, which is also expected to be applicable to bioremediation of other recalcitrant materials.