• Applied Biological Chemistry
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• v.37 no.3
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• pp.168-174
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• 1994

Effects of filtration and centrifugation on the oxidative stabilities of sesame oils during storage at $70^{\circ}C$ were studied by combination of determining peroxide values and conjugated dienoic acid values of oils and measuring the hexanal formation using headspace gas chromatography. Crude sesame oil from roasted seeds contained more free fatty acids, conjugated dienes, and metals (Fe, Cu, Mg and Zn); on the other hand, higher contents of moisture and ${\gamma}-tocopherol$ were found in the filtered or centrifuged oil. Only filtered oil contained more peroxides than the crude oil in spite of the color advantage of the highest L and b values among three oils. All the oils showed the tendency of increasing in total color difference during storage at $70^{\circ}C$, fatty acid compositions were relatively constant except for decreasing tendency of linoleic acid in filtered oil. No significant difference at 1% in the oxidative stabilities was observed between centrifuged oil and crude oil with higher susceptibility to the oxidation in the filtered oil. Centrifuged sesame oil was the best in the aspect of both oxidative stability and the oil color.

• Food Quality and Culture
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• v.1 no.1
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• pp.13-17
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• 2007

The volatile flavor compounds of Saussurea lappa C.B. Clarke, a perennial, aromatic and medicinal herbaceous plant of the Asteraceae family, were isolated by the hydro distillation extraction method using a Clevenger-type apparatus, and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The plant yielded a light yellow colored oil (0.02%, v/w). From S. lappa C.B. Clarke root oil, sixty-three volatile flavor compounds were tentatively identified, among which sesquiterpene was predominant (21.70%). The identified compounds of the root oil constituted 87.47% of the total peak area. From the constituents making up more than 5% of the volatile flavor components, a long-chain aldehyde, (7Z, 10Z, 13Z)-7, 10, 13-hexadecatrienal, was the most abundant volatile flavor compound (21.20%), followed by dehydrocostuslactone (10.30%) belonging to sesquiterpene lactone, valerenol (5.30%) and vulgarol B (5.06%).

• Journal of Korea Trade
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• v.27 no.5
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• pp.167-198
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• 2023

Purpose - This paper aims to compare and analyze the co-movements and information spillover effects between the international commodity futures markets and the South Korean stock markets during the COVID-19 and the 2008 financial crises. Design/methodology - The DCC-GARCH model is used in the co-movements analysis. In contrast, the BEKK-GARCH model is used to evaluate information spillover effects. The statistical data used is from January 1, 2005, to December 31, 2022. It comprises the Korea Composite Stock Price Index data and daily international commodity futures prices of natural gas, West Texas Intermediate crude oil, gold, silver, copper, nickel, soybean, and wheat. Findings - The results of the co-movement analysis were as follows: First, it was shown that the co-movements between the international commodity futures markets and the South Korean stock markets were temporarily strengthened when the COVID-19 and 2008 financial crises occurred. Second, the South Korean stock markets were shown to have high correlations with the copper, nickel, and crude oil futures markets. The results of the information spillover effects analysis are as follows: First, before the 2008 financial crisis, four commodity futures markets (natural gas, gold, copper, and wheat) were shown to be in two-way leading relationships with the South Korean stock markets. In contrast, seven commodity futures markets, except for the natural gas futures market, were shown to be in two-way leading relationships with the South Korean stock markets after the financial crisis. Second, before the COVID-19 crisis, most international commodity futures markets, excluding natural gas and crude oil future markets, were shown to have led the South Korean stock markets in one direction. Third, it was revealed that after the COVID-19 crisis, the connections between the South Korean stock markets and the international commodity futures markets, except for natural gas, crude oil, and gold, were completely severed. Originality/value - Useful information for portfolio strategy establishment can be provided to investors through the results of this study. In addition, it is judged that financial policy authorities can utilize the results as data for efficient regulation of the financial market and policy establishment.

• Clean Technology
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• v.16 no.1
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• pp.26-32
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• 2010

The low temperature pyrolysis of polypropylene (PP), polystyrene (PS) and polypropylene-polystyrene (PP-PS) mixture in a batch reactor at the atmospheric pressure and $450^{\circ}C$ was conducted to investigate the synergy effect of PP-PS mixture on the yield of pyrolytic oil. The pyrolysis time was varied from 20 to 80 mins. The products formed during pyrolysis were classified into gas, gasoline, kerosene, gas oil and heavy oil according to the petroleum product quality standard of Ministry of Knowledge Economy. The analysis of the product oils by GC/MS(Gas chromatography/Mass spectrometry) showed that new components were not detected by mixing of PP and PS. There was no synergy effect according to the mixing of PP and PS. Conversions and yields of PP-PS mixtures were linearly dependent on the mixing ratio of samples except for heavy oil yields. Heavy oil yields showed almost constant regardless of the mixing ratio.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.247-254
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• 2014

The synthesis of Fischer-Tropsch oil is the catalytic hydrogenation of CO to give a range of products, which can be used for the production of high-quality diesel fuel, gasoline and linear chemicals. Our cobalt based catalyst was prepared Co/alumina, silica and titania by the incipient wet impregnation of the nitrates of cobalt and promoter with supports. Cobalt catalysts was calcined at $350^{\circ}C$ before being loaded into the FT reactors. After the reduction of catalyst has been carried out under $450^{\circ}C$ for 24hrs, FT reaction of the catalyst has been carried out at GHSV of 4,000/hr under $200^{\circ}C$ and 20atm. From these test results, we have obtained the results as following ; in case of 12wt% Co-supported $Al_2O_3$, $SiO_2$ and $TiO_2$ catalysts, maximum activities of the catalysts were appeared at the promoters of Mn, Mo and Ce respectively. The activity of 12wt% $Co/Al_2O_3$ added a Mn promoter was about 3 times as high as that of 12wt% $Co/Al_2O_3$ catalyst without promoters. When it has been the experiment at the range of reaction temperature of $200{\sim}220^{\circ}C$ and GHSV of 1,546~5,000/hr, the results have shown generally increasing the activities with the increase of reaction temperature and GHSV.

• 전기의세계
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• v.30 no.6
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• pp.357-365
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• 1981

When electronegative gas SF$_{6}$ is dissolved and charged with insulating oil, the effect caused in the process by electronegative characteristic is studied and also the pressure effect caused by electronegative SF$_{6}$ acting on the liquid-level is examined respectively. When inert gas Ar is used to find a pressure effect acting on the liquid-level, its effect on dielectric strength is considered in the experiment. With three kinds of impulse voltage different in the duration of wave front and wave tail, a brief experiment if carried out ot see the effects on the dielectric breakdown characteristic as the wave is changing; either if I$_{2}$ and SF$_{6}$ are added to the insulating oil, or if the oil pressure is increased by Ar the dielectric strength becomes great and the longer the duration of wave front is, the greater the increase of the breakdown voltage, because I$_{2}$ added by a small quantity brings about some hirderance in the formation of gas phase. Likewise, the greater the changed pressure is, the greater the incerase of the breakdown voltage. When SF$_{6}$ is charged, the electronegative characteristic is prevailing at the time of low balanced pressure, and the pressure effect at the time of high balanced pressure.ressure.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.803-812
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• 2023

The subsea separator of an offshore plant for offshore oil and gas development performs the process of separating oil and gas from crude oil produced in the subsea. The oil-gas subsea separator can be divided into a gravity type that separates fluids by gravity and an in-line type that separates fluids using centrifugal force of density. In the case of the deep sea, the development of a small in-line type separator is required due to manufacturing cost and safety problems caused by water pressure. Therefore, in this study, the gas-liquid phase separation efficiency of the subsea separator was identified through the study of the multiphase flow characteristics of the in-line type separator. For the optimal design of the in-line type separator, the shape of the internal swirl element(ISE) was selected first, and the separation efficiency results for each section of the in-line type separator were analyzed. This study was conducted in parallel with experiments and numerical analysis, and it is expected that the reliability and efficiency of the in-line type separator will be improved through the results.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.444-445
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• 2008

This paper reviews the known techniques for diagnosing the condition of OF cable system and improving the service reliability. These tests are periodically achieved and intended to provide indications that the insulation system has deteriorated. One of these tests is analyzing the gas in oil on Oil-filled cable that is well known and widely accepted method. In this paper, this method of analysis and the relevant measurement standards overview and the concrete example of preventing fault incidence by performing this test is introduced.

• Journal of Energy Engineering
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• v.16 no.2
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• pp.53-57
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• 2007

High oil prices and high demand supporting IOC move to frontier and NOC evolution. Most frontier area reserves are in NOC territory. IOCs need to be able to manage relationships with NOCs in order to be successful. They need to tune into what NOC priorities are. NOCs have different priorities depending on whether they are resource rich or resource poor. IOCs need to recognize $NOCs^{\circ}{\emptyset}$ priorities and differentiate themselves by using them when talking to NOCs.

• Tribology and Lubricants
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• v.31 no.4
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• pp.141-147
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• 2015

Gas foil thrust bearings (GFTBs) have attractive advantages over rolling element bearings and oil film thrust bearings, such as oil-free operation, high speed stability, and high-temperature operation. However, GFTBs have lower load carrying capacity than the other two types of bearings owing to the inherent low gas viscosity. The load carrying capacity of GFTBs depends mainly on the compliance of the foil structure and the formed hydrodynamic wedge, where the gas pressure field is generated between the top foil and the thrust runner. The load carrying capacity of the GFTBs is very important for the suitable design of oil-free turbomachinery with high performance. The aim of the present study is to identify the characteristics of the load carrying performance of GFTBs. A new test rig for the experimental measurements is designed to provide static loads up to 800 N using a pneumatic cylinder. The maximum operating speed of the driving motor is 30,000 rpm. A series of experimental tests—lift-off test, static load performance test, and maximum load capacity test—estimate the performance of a six-pad GFTB, in terms of the static load, driving torque, and temperature. The maximum load capacity is determined by increasing the static load until the driving torque rises suddenly with a sharp peak. The test results show that the torque and temperature increase linearly with the static load. The estimated maximum load capacity per unit area is approximately 80.5 kPa at a rotor speed of 25,000 rpm. The test results can be used as a design guideline for GFTBs for realizing oil-free turbomachinery.