• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.307-313
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• 1998

This paper presents the experimental results of the friction characteristics of double lip-type oil seals which show an improvement in sealing performance over single lip-type oil seals. The major differences between two oil seals are the number of contact lip and seal materials; Nitrile Butadine Rubber(NBR) and urethane rubber. The measured results show that the friction torque of double lip seals shows 12-17% increases compared with those of single lip-type seals. But the sealing performance and service life of double tip oil seals have been increased and stabilized due to an optimized design of the seal lip and material properties.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.6
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• pp.568-576
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• 1990

Recently, streaming electrification in forced oil cooled power transformer has been taken up as a serious problem. In this paper, the charging tendency of various insulation oils, such as mineral oil, polybutene and silicone oil has been measured by means of an injection type charging tendency measuring apparatus under various condition. The experimental data of the dependence of the leakage current on flow velocity and temperature of oil can be explained by considering the flow state such as laminar and turbulent flow. The effect of additives on the charging tendency of mineral oil has been investigated. BTA is regarded as the most effective retardant to electrification of oil among the additives chose for this investigation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.471-481
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• 2005

Heavy crudes (bitumen) are extremely viscous and contain high concentrations of asphaltene, resins, nitrogen and sulfur containing heteroaromatics and several metals, particularly nickel and vanadium. These properties of heavy crude oil present serious operational problems in heavy oil production and downstream processing. There are vast deposits of heavy crude oils in many parts of the world. In fact, these reserves are estimated at more than seven times the known remaining reserves of conventional crude oils. It has been proven that reserves of conventional crude oil are being depleted, thus there is a growing interest in the utilization of these vast resources of unconventional oils to produce refined fuels and petrochemicals by upgrading. Presently, the methods used for reducing viscosity and upgradation is cost intensive, less selective and environmentally reactive. Biological processing of heavy crudes may provide an ecofriendly alternative or complementary process with less severe process conditions and higher selectivity to specific reactions to upgrade heavy crude oil. This review describes the prospects and strengths of biological processes for upgrading of heavy crude oil.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.2
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• pp.72-75
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• 2005

In oil-filled equipment such as transformers, partial discharge or local overheating will precede a final shutdown. Accompanied with such problems is a decomposition of insulating material into gases, which are dissolved into the transformer oil. The gases dissolved in oil can be separated with some membranes based on the differences in permeability of membranes to different gases. This paper discuss the permeability characteristics of several membranes for separation hydrogen gas in oil. With result of this paper, it may become possible to detect fault-related gases from transformer oil and predict incipient failures in the

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12
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• pp.1136-1141
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• 2003

The primary insulation materials used in an oil filled transformer are kraft paper, wood, porcelain and oil. Modern transformers use chemically treated paper to improve its tensile strength and resistance to aging caused by immersion in oil. But these insulation papers are mainly aged by thermal stress. Over the life time of the insulation paper and oil, it is exposed to high temperatures, oxygen and water. Its interaction with the steel of the tank and core plus the copper and aluminium of the windings will eventually cause the chemical properties of the oil to decay. High temperature have an effect on mechanical strength of cellulous paper used in the layer insulation. We made two aging cells in which insulation papers and mineral oil are conducted to test thermal properties. It is measured dielectric strength, number of acid, moisture, etc. of insulation paper and oil aged in the aging cells.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1594-1596
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• 2001

The purpose of this paper is to provide the fundamental data which can be used for the design of pole transformers. For the purpose, electrical characteristics of aged mineral oil and silicone oil were analyzed by comparing with the results of virgin ones. For the experiment, an oil bath which can keep constant temperature was constructed to thermally deteriorate the specimens. And transformer materials were put together in the bath according to the their ratio in weight in the pole transformer. And the parameters such as relative permittivety, tan$\delta$ and specific resistance were measured. As a results, the permittivity of silicone oil was higher than that of mineral oil, and its decreasing rate with temperature was also higher. In addition, it was found that tan$\delta$ and specific resistance of virgin and aged oil began to differ at similar temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.49-52
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• 2004

New hydrophobic alumina nanoparticles were synthesized from alumina powders which were hydrophilic nano-agglomerates with diameters from ${\mu}m$ to mm by surface modification. The synthesized hydrophobic alumina nanoparticles which were retreated with Oleic acid were analyzed by Fourier transform infrared spectrophotometer and transmission electron microscopy. Then transformer oil containing surface-modified alumina naonparticles were synthesized. The synthesized hydrophobic alumina nanoparticles were well-dispersed in transformer oil. The coefficient of viscosity and dielectric strength of the Nano-transformer oil were investigated with viscometer and high voltage experiment device. In this study, the thermal conductivity of Nano-transformer oil was investigated to reduce the oil temperature of transformer by transient hot-wire method.

• Journal of the Korean Society of Fashion and Beauty
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• v.2 no.2 s.2
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• pp.101-106
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• 2004

Allergic contact dermatitis is a common skin disease resulting from specific immunologic sensitization to topically applied various allergen. The Purpose of this study was to investigate skin morphologic cahnges by light microscopic and scanning electron Microscope, changes of protein band by SDS-PAGE(SDS-polyacrylamide gel electrophoresis) in the skin effectiveness for beruty improvement of Geranium essential oil on skin troubles by surfactant. The results of the study are as follows, 1. From the observed result of FE-Scanning Electron Microscope, groups treated by Geranium essential oil in group treated Geranium essential oil during 1 week in surfactant treated group during 1 week, the group was repaired in irregularity surface of tissue by alleviate-keratinization of Geranium essential oil. 2. As a result of protein analysis the group treated on surfactant was rised protein upper range of 97,0004a11on by hyper-keratinization and group treated during 1 week by surfactant was decreased protein below range of 43,000dalton.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.7
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• pp.885-893
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• 2012

DME (Dimethyl ether) is regarded as one of the candidates of alternative fuels for diesel engine, because of its higher cetane number suitable for a compression ignition engine. Also, DME is a simple chemical structure, colorless gas that is easily liquefied and transported. On the other hand, Bunker oil (JIS C heavy oil) has long been used as a basic fuel in marine diesel engines and is the lowest grade fuel oil. In this study, the combustion and emission characteristics were measured experimentally in the direct injection type diesel engine operated with DME and Bunker oil mixed fuel. From our experimental results, it is induced that DME and Bunker oil blended fuel would be an effective fuel which can reduces the concentration of harmful matter in exhaust gases.

• Journal of Ship and Ocean Technology
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• v.1 no.2
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• pp.41-49
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• 1997

We reviewed various oil-spill models and condensed the integrated information into a prediction model, “Green Sea Ranger”which is applicable to Korean coastal area. The developed software consists of pre- and post-modules for environment setup and display of results and main module for the prediction of oil\`s fate. In the pre-module target areas can be selected from the included geographic information system and various environmental and optional numerical data for the prediction can be input through easy GUI or imported from the database we established. For the fate of the spilt oil we included effects of spreading, advection, evaporation, and emulsification. Preliminary numerical experiment has proved that the developed oil-spill prediction system can be easily utilized in on-site oil recovery operations which usually require a quick and reasonable prediction.