• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1277-1282
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• 2011

Recently, many car drivers were damaged by gas station which support similar oil product and not quantitative gas. It were expected to increase above-mentioned damages. By using similar oil products, caused damage are working of lubrication in the fuel line, elf-cleaning function, the part of the early deterioration, impure accumulation in the fuel line, toxicity material in exhaust emissions and unidentified chemical reaction. To prevent these damages, proposed system use in-vehicle state data with OBD-II protocol, measure quantitative gas and similar oil. In this paper, there have implemented similar oil identification and quantitative gas system through OBD-II scanner to provide WiFi communcation by using WinCe development Board.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.135-144
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• 2015

The Korean daily intake of vegetable oils has increased about 2.5-fold from 17 g/day to 46 g/day for the last several decades. Perilla (Perilla frutescens var. frutescens) has been cultivated in Korea for a long time as a dietary oil seed which has the highest content of ${\alpha}$-linolenic acid, accounting for nearly 60%. It is known that the main role of ALA is as a precursor to the longer-chain ${\omega}-3$, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), the metabolic products of ${\alpha}$-linolenic acid (ALA, ${\omega}-3$). Dietary ${\omega}-3$ fatty acids reduce inflammation and the risk of chronic diseases such as heart disease, cancer, and arthritis, but they also may act as functional components for cognitive and behavioral function. Thus, ${\alpha}$-linolenic acid is one of the essential nutrients in modern dietary patterns in which much linoleic acid is consumed. Nevertheless, perilla oil, rich in ${\alpha}$-linolenic acid, can be easily oxidized, giving rise to controversies with respect to shelf life, the deterioration of the product's commercial value, and further related toxicity. Recent research using genetic modifications has tried to develop new plant oil seeds that balance the ratio of ${\omega}-6/{\omega}-3$ fatty acids. Such trials could be a strategy for improving an easily oxidizable property of perilla oil due to high ${\alpha}$-linolenic acid. Alternatively, appropriate application of antioxidant to the oil can be considerable.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.27-37
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• 2019

The shell and tube heat exchangers installed in the propulsion system test complex (PSTC) at the Naro Space Center heats cryogenic helium to 500 K with a heat transfer oil. As the experimental helium outlet temperature was lower than expected (less than 100 K), the boundary layer effect of the heat transfer oil is predicted to be the cause of the performance deterioration. A computational fluid dynamics (CFD) analysis was performed to verify where the boundary layer effect exists; however, the boundary layer effect has no significant impact on the performance of the heat exchanger. An alternative method to improve the performance of the heat exchanger by changing the heat transfer oil has been discussed in this paper. The low viscosity and high thermal conductivity at high temperature (~500 K) of heat transfer oil at the shell-side are required to improve the thermal performance of the heat exchanger. The experimental performance of the heat exchanger, used to exchange heat between the cryogenic helium and hot heat transfer oil at the PSTC are summarized in this paper.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.906-915
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• 2006

In this study, Field test was performed using high-quality additions and accelerators to obtain the improvement of the strength on domestic shotcrete and quality test based on EFNARC was performed. In addition, Deterioration test that combined the Freezing-thawing and Carbonation was also performed in order to investigate a long-term durability of high-strength shotcrete. As a result of field test, a promotion ratio of early strength is $90\sim97%$ in case of using alkali-free accelerators. And a compressive strength of shotcrete using Micro-silica fume was $45.2\sim55.8MPa$ and the flexible strength was $5.01\sim6.66MPa$, so a promotion ratio of strength was $37\sim79%$, $17\sim61%$ respectively. It was showed that increment effect of strength by the Micro-silica fume replacement of $7.5\sim10%$ for cement mass was remarkable. It was also realized that application of Micro-silica fume to shotcrete reduced deterioration and improved a long-term durability of shotcrete.

• Tribology and Lubricants
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• v.24 no.4
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• pp.179-185
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• 2008

Microporous polymer lubricants(MPLs) are solid polymer materials containing micropores which are filled with liquid lubricants, and which are molded or formed to suit rolling bearings or other machine parts requiring lubrication. MPLs can be effectively applied to provide long-term, maintenance-free lubrication of a variety of machine elements without fully replacing of oils and greases. The application of rolling bearings packed fully with an MPL could reduce or eliminate the problems such as grease deterioration, leakage, under-lubrication caused by insertion of water or foreign matters under severe operation conditions. This paper discuss the application of MPLs for lubrication of rolling ball bearings. Two different MPLs were synthesized and the features of MPLs were tested. Characteristics of the bearings which are packed fully with synthesized MPLs were investigated using SEM, TG/DSC, extents of oil leakage, OIT, and life time test. After these preliminary tests twelve MPLs were synthesized and evaluated by measuring extents of oil leakage and OIT values. Then synthesis conditions for the optimum MPL were selected by SSRED(Six Sigma Robust Engineering Design) pro gram using extents of oil leakage and OIT values respectively. The optimum MPL by means of OIT value showed higher performance such as long life time and application at higher temperature of $140^{\circ}C$ than previous temperature of $100^{\circ}C$.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.2
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• pp.47-55
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• 1995

When the low heavy oil is using as fuel oil to the diesel engine, some problems such as corrosion resistance, wear resistance and heat resistance are happened in diesel engine's internal material, especially the adhesive wear of piston ring groove was occurred as a important problem. Therefore to prevent adhesive wear of its groove, the surface of its groove used to be electroplated with Chrominum and for its Chromium electroplating, Fe anode is being used until nowadays because of its Special shape. However in case of using Fe anode, there were some problems such as deterioation of solution, property of Chromium film, and condition of coation. In this paper Pb anode electroplated withPb to the steel plate was investigated for its Chromium electroplating for Pb's high corrosion resistance in acid solution, and Pb anode is not dissolved compared with Fe anode and deterioration degree of solution in case of Pb anode is smaller than that of Fe anode and also property of Chromium film was better than that of Fe anode. Moreover it was known that the optimum cathodic current density for Pb electroplating to steel plate as insoluable anode for Chromium coating of piston ring groove is 30mA/$cm^2$ by experimental results obtained.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.146-151
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• 1987

The storage stability of sardine oil and the effect of BHA on the oxidation of fatty acids especially, highly unsatureted fatty acids like EPA and DHA were investigated. The sardine oil was extracted from round sardine, with chloroform-methanol(2:1 v/v) solvent with/without addition of BHA, and then stored at $30^{\circ}C$. The deterioration of oil was examined periodically by measuring acid value(AV), peroxide value(POV), carbonyl value(COV), and oxygen absorption. The changes in fatty acid composition during the storage was determined by GLC analysis to elucidate the oxidative stability of individual fatty acid. Formation of free fatty acid increased rapidly according to the storage time elapsed in the BHA free oil while it was obviously inhibited in the BHA added oil. Peroxides and carbonyl compounds were formed very rapidly at the beginning of storage of BHA free oil. But in the oil extracted with BHA, formation of peroxides was somewhat inhibited and formation of carbonyl compounds was very strongly inhibited. Principal fatty acids of sardine oil were $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{20:5}\;and\;C_{22:6}$ acids, and $\omega_33$ polyunsaturated fatty acid $(\omega_3\;PUFA)$ content was very high as much as $23\%$ of the total fatty acid content. The oxidative degradation of fatty acids was enhanced at PUFA especially $C_{20:5}$ ana $C_{22:6}$ acid in BHA free oil. However, the oxidation was fairly retarded in the oil extracted with BHA and the both $C_{20:5}$ and $C_{22:6}$ acids remained at the end of a month storage.

• Advances in Energy Research
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• v.1 no.2
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• pp.147-163
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• 2013

The world faces several issues of energy crisis and environmental deterioration due to over-dependence on single source of which is fossil fuel. Though, fuel is needed as ingredients for industrial development and growth of any country, however the fossil fuel which is a major source of energy for this purpose has always been terrifying thus the need for alternative and renewable energy sources. The search for alternative energy sources resulted into the acceptance of a biofuel as a reliable alternative energy source. This work presents the study of optimization of process of transesterification of vegetable oil to biodiesel using NaOH as catalyst. A $2^4$ factorial design method was employed to investigate the influence of ratio of oil to methanol, temperature, NaOH concentration, and transesterification time on the yield of biodiesel from vegetable oil. Low and high levels of the key factors considered were 4:1 and 6:1 mole ratio, 30 and $60^{\circ}C$ temperatures, 0.5 and 1.0 wt% catalyst concentration, and 30 and 60 min reaction time. Results obtained revealed that oil to methanol molar ratio of 6:1, tranesetrification temperature of $60^{\circ}C$, catalyst concentration of 1.0wt % and reaction time of 30 min are the best operating conditions for the optimum yield of biofuel from vegetable oil, with optimum yield of 95.8%. Results obtained on the characterizzation of the produced biodiesel indicate that the specific gravity, cloud point, flash point, sulphur content, viscosity, diesel index, centane number, acid value, free glycerine, total glycerine and total recovery are 0.8899, 4, 13, 0.0087%, 4.83, 25, 54.6. 0.228mgKOH/g, 0.018, 0.23% and 96% respectively. Results also indicate that the qualities of the biodiesel tested for are in conformity with the set standard. A model equation was developed based on the results obtained using a statistical tool. Analysis of variance (ANOVA) of data shows that mole ratio of ground nut oil to methanol and transesterification time have the most pronounced effect on the biodiesel yield with contributions of 55.06% and 9.22% respectively. It can be inferred from the results various conducted that vegetable oil locally produced from groundnut oil can be utilized as a feedstock for biodiesel production.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1571-1577
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• 2013

Electrical tree structure is one of the most important influencing factors for electrical treeing characteristics in polymers. In this paper, we focused on the structure characteristics of electrical treeing in epoxy resins (original) insulation under different high-frequency voltages (60, 500, 1000Hz). Effects of voltage frequency on the ac electrical treeing phenomena in an epoxy resins were carried out in needle-plate electrode arrangement. To measure the treeing initiation and propagation, and the breakdown rate, constant AC of 10 kV with three different voltage frequencies (60, 500 and 1,000 Hz) was applied to the specimen in needle-plate electrode specimen at $30^{\circ}C$ of insulating oil bath. At 60 Hz, the treeing initiation time was 360 min and the propagation rate was $6.85{\times}10^{-4}mm/min$, and the morphology was dense branch type. As the voltage frequency increased, the treeing initiation time decreased and the propagation rate increased. At 1,000 Hz, the treeing initiation time was 0 min and the propagation rate was $7.81{\times}10^{-2}mm/min$, and the morphology was dense bush type.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1865-1867
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• 2002

In this paper, frequency spectra of AE signals detected from respective the insulation deterioration were analysed to under ac high-voltage application using epoxy resin sample and insulation oil. Also, frequency spectra of AE signals generated from the load currents in the actual operating transformer of 500[kVA] under distribution system of 22.9[kVJ] were also analysed to distinguish the AE signals due to void discharges from the magnetic circuit noises in transformer. As the experimental results, we could distinguish the AE signals whether those signals were caused due to the void discharges or due to the magnetic circuit noises by analyzing the frequency spectrum of AE signals.