• Tribology and Lubricants
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• v.24 no.1
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• pp.7-13
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• 2008

In this work, a simple and low cost sensor technique is proposed to test oil color in real time using in-line sensor. It is presented to use a ratio of intensity in red wavelength range to intensities of green and blue wavelength ranges (defined as a 'chromatic ratio') in order to estimate the oil color change. The proposed sensor technique is realized by irradiating a white LED as light source and a RGB color sensor as photoreceiver, and the chromatic ratio of various types of used oils are measured. The results show that chromatic ratio generally reflects chemical deterioration of oil, including oil oxidation and thermal degradation. It is concluded that the proposed sensor could be used for an effective oil monitoring technology.

• Journal of the Korean Society of Combustion
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• v.19 no.2
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• pp.28-36
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• 2014

Bio fuel oil combustion experiments were successfully demonstrated at the 75 MWe oil-fired power plant without major equipment retrofit and 100% bio-fuel oil combustion was possible without big problems. The experimental data error correction was conducted and numerical model-based analysis technique was applied for the evaluation of the results. Incase of bio fuel oil combustion, heat absorption of radiative heat transfer section was reduced while convection section has opposite trend. The furnace exit gas temperature tends to rise slightly. Environment emissions such as NOx and SOx concentrations showed a tendency to decrease during the bio fuel oil combustion period. On the other hand, boiler efficiency was slightly underestimated.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.22-28
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• 2008

Generally block imbedded type oil pump is adopted to make a small engine. In this paper 1D/3D numerical simulations were conducted to reduce energy consumption of the block imbedded type oil pump. At each stage of engine development we have estimated the oil flow rate and pressure to optimize oil pump sizes by using the 1D system analysis and then accomplished 3D CFD(Computational Fluid Dynamics) simulations to optimize oil pump shapes including inlet/outlet port. As a result, the energy consumption of oil pump has been reduced to nearly 27% and the engine fuel consumption to $1{\sim}1.5%$.

• Journal of the Korean Applied Science and Technology
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• v.10 no.1
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• pp.39-47
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• 1993

This study was performed observe the effect of vegetable oil on the liver of 0.5% cholesterol-fed rats. In this experiment, male rats of Sprague-Dawley strain were used. The rats were divided into 5groups which were fed differently either for 8 weeks: basal diet, 20% sunflower oil diet, 20% soybean oil diet, 20% rapeseed oil diet.,20% coconut oil diet. The total cholesterol, triglyceride level in the liver were showed tendency of increase with increasing of P/S ratios. Bile acid excretion in the fecal increased with increasing of P/S ratios. The value of TBA in the serum and liver were increased in proportion to the amount of polyunsaturated fatty acid. The liver fatty acid of coconut-fed group showed larger variation than fatty acid of the cocount oil. The fat chang of sunflower oil diet in the liver showed the largest change.

• Journal of the Korean Applied Science and Technology
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• v.28 no.4
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• pp.431-437
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• 2011

Transparent liquid crystal gels with high oil content by fatty acid soap were investigated. The solubilization efficiency of the mineral oil was dependent on the process. The process of dropping water part into the solution of oil and surfactant was more efficient than the process of dropping water part into the surfactant solution and after that dropping oil. The fatty acid soap could not solubilize the high oil content, but under the certain range, addition of CDE (Coconut Diethanolamide), Arlacel 165 (Glyceryl Stearate/PEG-100 Stearate) and cetostearyl alcohol helped solubilize the high content oil. Also, the glycerin and water content had influence on the solubilization. Especially, higher oil content gel showed elastic feature.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.128-130
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• 2000

This paper develops the deterioration detecting sensor in oil to monitor and diagnose oil-filled transformer more effectively. The on-line inspection of the oil-filled transformers used the temperature, the changes of the capacitance, the $tan{\delta}$ in oil. This sensor was designed based on the concentric cylindrical type so that it could be placed inside of the oil-filled transformer. And comparing to the existing system, it was proven to be appropriate. Establishment of the proposed sensor helps to build the confidence in monitoring of the oil-filled transformers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.4
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• pp.518-527
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• 1999

The solubility and miscibility measurement apparatus has been developed and used to obtain data for refrigerant/oil mixture. The solubility and miscibility data for R-134a/46 ISO VG Polyalkylen Glycol(PAG) oil mixture are obtained over the temperature range from -20 to 6$0^{\circ}C$ with a 1$0^{\circ}C$ interval and the oil concentration range from 0 to 90wt%. Using the experimental data, an empirical model is developed to predict the solubility relations for R-134a/PAG oil mixture at equilibrium. The average root-mean-square deviation between measured data and calculated results from the empirical model is 4.2%. Raoult's rule and Flory-Noggins theory are also used to predict mixture behavior. Immiscibility is observed for R-134a/46 ISO VG PAG oil mixture at low oil concentrations of 4.6, 10.1, and 20.4wt%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.43-46
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• 1997

The results of an investigation conducted to study the effect of crude oil contamination on the geotechnical properties of sand of presented. The effect of the degree of oil contamination on compaction characteristics, shear strength, and one-dimensional compression characteristics has been investigated. The test results indicate that the compaction characteristics are somewhat influenced by oil contamination. The angle of internal friction of sand (based on total stress basis) decreases due to the presence of oil within the pore spaces in sand. The compression characteristics of sand are significantly-influenced by oil contamination. The details of the tests conducted and the results are presented in the paper.

• Tribology and Lubricants
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• v.20 no.2
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• pp.84-90
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• 2004

It is very important to improve the durability and reliability of crankshaft because of conflicting demands for lower fuel consumption and higher power output. In this study, for the crankshaft bearing design, analyses were conducted to determine the lubrication characteristics such as oil flow rate, minimum oil film thickness, friction force and increase of oil temperature at main bearing and connecting rod bearing. Additionally, supplied oil pressure and temperature effects on the bearings were simulated to figure out lubrication characteristics on the bearings. Finally the effects of increasing the bearing width and clearance were introduced on the lubrication characteristics.

• Tribology and Lubricants
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• v.29 no.1
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• pp.51-55
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• 2013

In this work, a new fluorescence emission measurement technology was introduced and experimentally compared with other measurement methods, such as the titration method and IR spectroscopy, to validate it for the oil oxidation measurement of electrical insulating oil. The oxidation characteristics of insulating oil were found to be fairly represented by the titration method and IR spectroscopy, and the results are comparable to a change in the fluorescence emission ratio that is defined as the shift in fluorescence intensity in the measured wavelength range. The result also shows that by the measurement of fluorescence emission ratio, it is possible to detect the oxidation of oil relatively earlier than by other methods. This study suggests that the developed technology can provide sufficient information for evaluating the insulating oil quality, and that the developed FER sensor can be used as an effective condition monitoring device of electrical insulating oil oxidation.