• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1664-1670
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• 2015

As journal bearing has a sliding motion between the shaft and bearing with lubricating oil, it produces a hydrodynamic lubrication condition. Journal bearing can receive a large force because it takes a distributed load at the large friction face. As the oil groove or oil hole is made in the journal bearing surface for the journal bearing smoothly working under a hydrodynamic lubrication condition, sufficient lubricating oil is supplied through the clearance of journal bearing. The performance of the journal bearing is changed according to the shapes, sizes and positions of an oil groove. In this paper, the flow rate according to the oil groove shapes (triangle, semicircle and rectangle) among the various oil supply conditions was measured. The shape that discharges the highest flow rate was observed and the groove shape of optimal performance for the journal bearing was determined. The results showed that the flow rate increases with decreasing operating temperature, the influence of temperature on the flow rate decreased with increasing rotational speed, and flow rate in the triangular groove shape was greater than in other shapes.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.177-184
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• 2020

The objective of this study was to investigate the effect of cold-pressed flaxseed oil through the roasting temperature (unroasted and roasted at 150℃ and 200℃) and time (10 and 20 min) on the chemical changes. Cold-pressed flaxseed oil extraction yield was calculated with respect to the roasted process and total phenolic content, fatty acid composition, and volatile compound were analyzed. The extraction yield was increased in the roasted oil compared to the unroasted oil. Total phenolic content was significantly higher in oil from the roasted at 150℃ for 20 min compared to other roasting condition. Fatty acid composition was not affected by the extraction process. The content of aldehyde, ketone, furan, and pyrazine was higher than in the roasted at 200℃ compared to the unroasted and roasted at 150℃. These findings suggest that cold-pressed flaxseed oil extracted from the roasted at 150℃ for 20 min may be considered acceptable for safe extraction process.

• Tribology and Lubricants
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• v.24 no.1
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• pp.21-26
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• 2008

A pin bush bearing is one of the most important element in the piston engine which is joined a piston to a connecting rod. A pin bush is suffered by heat and changeable repeat loads, which are come from the explosive gas heat and pressures during a reciprocating stroke. Therefore, a tribological behavior of pin bush bearings is very severe compared to other parts of a piston assembly. To keep a stable operation of pin bush bearings effectively, it would be satisfied with proper oil film strength for severe operating conditions and durability, which are strongly related to the oil film thickness, oil film pressure, and a friction loss power. The computed results show that the viscosity of engine oils slightly affects to the minimum oil film thickness and oil film pressure distribution, but is an influential parameter on a total friction loss power. Thus the low viscosity engine oils for an increased operation condition should select a high level of base oil and add a viscosity index improver as an oil film additive.

• 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.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.161-164
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• 2005

Essential oils of three plants (caraway oil, hyssop oil and lime oil) were screened for repellency against Tetranychus urticae female adults in the lab condition. Among them, caraway oil (Carum carvi) showed $92.2\%$ repellency against female adults at 1,000 ppm concentration. Through the constituent analysis using GC and GC/MS, we confirmed that the two main constituents were carvone $(73.3\%)$ and limonene (26.7). Limonene showed 87.8 and $83.1\%$ repellency against adult females at 1,000 and 100 ppm concentrations, respectively.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.111-112
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• 2002

The influence of aerated oil on a high-speed proceeding bearing is examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing including the live surface tension of aerated oil. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil aeration level, air bubble size and shaft speed. The results show that, if the live surface tension is considered, the effect of air bubbles on the bearing load capacity is reduced due to temperature engagement comparing with that under the condition of a constant surface tension.

• Journal of the Korean Applied Science and Technology
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• v.28 no.4
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• pp.464-471
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• 2011

Sesame oil is a simple pressed oil as unrefined oil. During manufacturing process of roasting-expression, benzo(a)pyrene[B(a)P] formed as a strong carcinogenic substance is cause a social problem. In manufacturing process of sesame oil, it had following the forming pathway of benzo(a)pyrene[B(a)P] as well as minimizing plan of B(a)P formation. Suitable roasting condition by roaster was during 15~20min at $220^{\circ}C$, B(a)P content in sesame oil was $1.35{\sim}1.57{\mu}g/kg$. Between roasting temperature and/or roastingtime and forming amount of B(a)P was showed a linear correlation. As a point of view the turbidity and yield of final product, roasting process of the more regular level was required.

• 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.

• 한국해양학회지
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• v.21 no.2
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• pp.118-123
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• 1986

A gas chromatographic oil fingerprinting method is a technique used for comparative source identification of spilled oil. The hydrocarbon and sulfur compound analysis by gas chromatography are generally used for analyzing oils. However, due to the complexity of oils, another technique is also needed for comparative identification. In this study, polycyclic aromatic hydrocarbons contained in crude oil and heavy fuel oil are analyzed by gas chromatography. They are relatively unaffected by weathering condition because they are stable. The oil fingerprinting of polycyclic aromatic hydrocarbons by GC seems to be a reliable technique for analyzing oils in identification of sources and kinds of oils.

• Journal of the Korean Professional Engineers Association
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• v.45 no.6
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• pp.28-32
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• 2012

Namhae chemical is one of the largest fertilizer manufacturing company in Korea which company has operating 4 unit agitator gear boxes and producing variety kinds of fertilizer production. The gearbox operating temperature of agitator is approximated in $55^{\circ}C{\sim}90^{\circ}C$ and required to keep operating continuous without stopping. The system required high performance oil and longer oil drain interval as limited workforce in maintenance team. It was lubricated by mineral gear oil of ISO VG 320 and also need to change to new oil frequently. Namhae Chemical would expect to keep stable operating condition without shut down and consider, lower cost of operation and equipment protection.