• Tribology and Lubricants
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• v.21 no.6
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• pp.249-255
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• 2005

In this paper, the friction characteristic of engine bearings has been analyzed in terms of a friction loss power, a minimum film thickness and an oil film pressure. This analysis has been focused on the fuel economy improvement with a low viscosity engine oil such as SAE 0W-40, which is used for a friction loss reduction and increased for a Diesel fuel economy. The friction loss power, the minimum oil film thickness and oil film pressure distribution for plain bearings of a Diesel engine are analyzed using an AVL's EXCITE program with a conventional engine oils of SAE 5W-40 and 10W-40, and a low viscosity engine oil of SAE 0W-40. The computed results indicate that a viscosity of engine oils is closely related to the friction loss power and the decreased minimum film thickness in which is a key parameter of a load carrying capacity of an oil film pressure distribution. When the low viscosity engine oil is supplied to engine bearings, it does not affect to the formation of a minimum oil film thickness. But the friction loss power has been significantly affected by low viscosity engine oil at a low operating temperature of 0. Based on the FEM computed results, the low viscosity engine oil at a low temperature range will be an important factor for an improvement of the fuel economy improvement.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.941-953
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• 2019

Biodiesels are being explored as a clean energy alternative to regular diesel, which causes pollution. In this study, the optimum conditions for producing biodiesel (BD) by combining beef tallow, an animal waste resource with a high saturated fatty acid content, and corn oil, a vegetable oil with a high unsaturated fatty acid content, were investigated, and the fuel properties were analyzed. Furthermore, Multivariate Analysis of Variance (MANOVA) was used to verify the optimum conditions for producing biodiesel. The influences of control factors, such as the oil blend ratio and methanol to oil molar ratio, on the fatty acid methyl ester and biodiesel production yield were investigated. As a result, the optimum condition for producing blended biodiesel was verified to be tallow to corn oil blend ratio of 7 : 3 (TACO7) and a methanol to oil molar ratio of 14 : 1. Moreover, the interaction between the oil blend ratio and the methanol to oil molar ratio has the most crucial effects on the production of oil blended biodiesel. In conclusion, the analysis results of the fuel properties of TACO7 BD satisfied the BD quality standard, and thus, the viability of BD blended with waste tallow as fuel was verified.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.1
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• pp.9-18
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• 1999

To predict the oil spill dispersion phenomena in the ocean, the oil spill response model, which can be used for strategic purpose on the oil spill site, based on Lagrangian particle-tracking method was formulated and applied to the neighboring area with Pusan port where the oil spill incident occurred when the tanker ship No.1 Youil struck on a small rock near the Namhyungjeto on September 21, 1995. The real-time tidal currents to be required as input data of the oil spill model were obtained by the two-dimensional hydrodynamic model and the tide prediction model. Evaluation of tidal currents using observation data was successful. For wind data, other input data of oil spill model, observed data on the spot were used. To verify the oil spill model, the oil spill modelling results were compared with the field data obtained from the spill site. Compared the modelling results with the observation data, there exist some discrepancies but the general pattern of modelling results was similar to that of field observation. The modelling results on 7 days after spill occurred showed that the 40% of spilled oil is in floating, 36% in evaporated, 23% at shore, and 1% in out of boundary, respectively. According to the evaluation of weighting curves of effective components to the dispersion of oil, the winds make a 37% of contribution to the dispersion of oil, turbulent diffusion 39.5%, and tidal currents 23.5%, respectively. Provided the more accurate wind data are supported, more favorable results might be obtained.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.31-37
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• 1999

In order to predict thermodynamic performance of refrigeration system, it is required to know the oil concentration of the refrigerant/oil mixture. The current method to measure the oil concentration is to extract the working mixture and then to measure the oil weight. However, it is Quite necessary to estimate oil concentration without any extraction of the working fluid. In this study a new method and working equation is presented as follows. It is based on the measurement of spedific gravity and temperature : $$C=a+b{\times}t+c{\times}t^2+(d+e{\times}t+f{\times}t^2){\times}SG$$ C is oil concentration, t is temperature($^{\circ}C$), SG is specific gravity of mixture and a~f is coefficients. The oil concentration ranges over 0~12 wt% and the temperature ranges over $20{\sim}50^{\circ}C$. The specific gravity and temperature are measured using the on-line densimeter and thermometer. This working equation enables to predict the oil concentration without any extraction of the mixture. This equation can be applied for R-12/Naphthenic oil and R-134a/POE oil oiquid mixtures.

• New & Renewable Energy
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• v.19 no.4
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• pp.2-10
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• 2023

The current mandatory domestic biodiesel blending ratio is 3.5%, which is planned to be gradually increased to achieve carbon neutrality by 2050. The aim of this study was to improve domestic self-sufficiency in biodiesel raw oil by conducting a technical review on the possibility of utilizing waste oils, such as soup oil, chicken oil, and leather oil, as biodiesel feedstocks. These waste oils have an acid value that is too high to be converted directly into biodiesel. Therefore, a pretreatment to reduce the acid value is necessary. The neutralization process was examined as a potential technology for reducing the acid value. The oil recovery rate of the soup oil after neutralization was significantly low at 37.6 wt%. The oil recovery rates of leather oil and chicken oil were 66.49 wt% and 79.08 wt%, respectively. Based on biodiesel conversion experiment using waste oil with a reduced acid value, the conversions were analyzed as 89 wt%, 91.1 wt%, and 90.5 wt% for soup oil, leather oil, and chicken oil, respectively. Thus, it is technically possible to use soup oil, leather oil, and chicken oil as raw materials for producing biodiesel.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.78-79
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• 2003

Effects of dietary lipid level and source (squid liver oil being rich in n-3 HUFA, soybean oil being rich in 18:2n-6, and linseed oil being rich in 18:3n-3) in fishmeal-based diet on growth and body composition of grower sunshine bass raised in seawater were investigated. Fifteen grower (an initial weight of 146.8$\pm$0.23 g) sunshine bass were randomly distributed into 27 of 250 L fiber reinforced plastic flow-through tanks. Fish were hand-fed to satiety twice daily for 6 days a week throughout the feeding trial. Survival was over 97% and not significantly affected by either dietary lipid level or lipid source (n-3 highly unusaturated fatty acid, HUFA). Weight gain of fish tended to improve with dietary n-3 HUFA level up to 2.9%, but sharply decreased at 3.5%. The best weight gain was obtained in fish fed the diet supplemented with 6% squid liver oil and 3% soybean oil. FER and PER were not significantly affected by either dietary lipid level or dietary lipid source. The lowest moisture content of the whole body was observed in fish fed the diet supplemented with 12% squid liver oil and highest for the diet supplemented with 9% linseed oil, respectively. Protein content of fish was not significantly affected by either dietary lipid level or dietary lipid source. However, lipid content of the whole fish tended to increase with an increase of either dietary lipid level or dietary n-3 HUFA level, except for fish fed the diet supplemented with 9% linseed oil. Ash content of fish fed the diet with no supplementation of oil was highest and lowest for the diet supplemented with 9% soybean oil, respectively. Significant differences in saturated fatty acids (16:0, 18:0 and 24:0), monoene (18:1n-9), 18:2n-6, 20:5n-3 and sum of n-3 HFUA of fish were observed. In considering these results, it could be concluded that supplementation of 9% oil combined with 6% squid liver oil and 3% soybean oil into fishmeal-based diet was the most recommendable for growth of grower sunshine bass raised in seawater.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.291-292
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• 2002

Using a low viscosity synthetic traction oil and a low viscosity mineral oil with nearly equal viscosity grade of ISO VG 32, the effect of kind of oil on the fatigue life of bearing steel rollers was examined. A pair of rollers finished the contact surfaces to a mirror-like condition were driven under rolling with sliding conditions of s = -3.2% and a maximum Hertzian stress in the range of $P_H=2.8GPa{\sim}4.0GPa$ was applied in point contact condition. As a result of experiments, the fatigue life with a mineral oil was longer than that with a traction oil under higher stress conditions above $P_H=3.4GPa$. Based on the numerical calculation results of the thermal EHL which simulates the present experiment, the authors discuss the reason why such a difference in the fatigue life comes out.

• 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.

• 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.

• 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.