• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.254-261
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• 2014

The transformer is a static electrical device that transfers energy by inductive coupling. Then, heat is occurred at coils, inner transformer was filled with insulating oils for cooling and insulation. Although mineral oil as insulating oil has been widely used, it does not meet health and current environmental laws because it is not biodegradable. Therefore, in this study, the diglycerol ester was synthesized with diglycerol and fatty acids (oleic acid and caprylic acid) over various catalysts for insulating oil having biodegradability, high flash points and low pour points. The sulfated zirconia ($SO_4{^{2-}}/ZrO_2$) catalyst prepared at different calcination temperature shows the highest conversion of fatty acids at $600^{\circ}C$ due to crystallinity and high density of acid sites per surface area. When the molar ratio of oleic acid and caprylic acid is 1:3, the diglycerol ester shows superior insulation properties that are the flash point of $306^{\circ}C$ and pour point of $-50^{\circ}C$. The insulation properties of synthesized diglycerol ester shows the pour point of $-50^{\circ}C$ and the flash point of over $300^{\circ}C$. Therefore, diglycerol ester is superior to the vegetable oils in insulation properties.

• Korean Journal of Food Science and Technology
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• v.10 no.4
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• pp.409-414
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• 1978

The total amount of lipid content in the mullet roe is 20.5%, and iodine value and unsaponifiable matters content are 118 and 38.7%, respectively. The lipid composition of the muscle, roe and liver of the mullet, Mugil cephalus, shows differences. Triglyceride, wax esters, and free fatty acids are mainly contained in the lipids of the muscle, roe and liver, respectively. The mullet roe lipids are mainly composed of 59.1% of wax esters with a trace of sterol esters, 26.9% of polar lipids with pigments, 9.0% of triglyceride plus a trace of free fatty alcohols and fatty acids, and 3.0% of sterol contaminated with a trace of fatty alcohols. The major fatty acids of wax esters are C16 : 0, 47.5%, C18 : 1, 23.0%, C16 : 3, 6.5%, C20 : 5, 4.0%, those of triglyceride are C16 : 1, 25.1%, C18: 1, 16.7%, C16 : 0, 16.3%, C22 : 1, 7.9%, C18 : 0, 5.5%, C22 : 6, 4.4%, and those of polar lipids are C16 : 0, 35.0%, C18 : 1, 24.7%, C16 : 1, 6.1%, C20 : 5, 5.3%, C22 : 6, 4.2%. The major alcohols of wax esters are 51.0% of cetyl alcohol, 18.2% of palmitoleyl alcohol, and 10.7% of oleyl alcohol, and considerable amounts of odd-numbered alcohols such as C15 : 0, C15 : 1, C17 : 0, C17 : 1 and C19 : 1 are also found.

• The Korean Journal of Food & Health Convergence
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• v.9 no.4
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• pp.11-18
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• 2023

Oil was extracted from cashew nuts. The physicochemical parameters of the oil were determined. A chromatographic assay of the oil was carried out using Gas Chromatography-Mass Spectrometry. Seventeen compounds were detected: Phenol, Phenol 2-methyl-, Cyclohexene 4, 4-dimethyl-, m-Fluoro-2-diazoacetophenone 4-dimethyl-, Tetradecanoic acid, Phenol 4-octyl-, n-Hexadecanoic acid. Others are 9, 12-Octadecadienoic acid (Z, Z) - methyl ester, Hexadecanoic acid methyl ester, Methyl stearate, Dodecanoic acid methyl ester, 9, 12, 15-Octadecatrienoic acid methyl ester, 9, 12, 15-Octadecatrienoic acid (Z, Z, Z)-, Oleic acid, Octadecanoic acid, Tetracosanoic acid and 9-Octadecenoic acid methyl ester. Among the components are omega three and omega six essential free fatty acids. The rheological profiling and flow properties of cashew nut oil were determined using a Programmable Rheometer. Cashew nut oil exhibits slight dilatant behaviour at the low end of shear rate. The long chain and high molecular weight of its constituents controlled its rheology. Long-chained 9-Octadecenoic acid methyl ester, 9, 12-Octadecadienoic acid (Z, Z) - methyl ester, Tetracosanoic acid and methyl stearate, coupled with their high molecular weights are responsible for the shear thickening effect observed. Two models, Carreau-Yasuda and Ostwald-de Waele Power Law were employed to fit the rheological data. The Carreau-Yasuda model followed well the data.

• Journal of Environmental Science International
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• v.19 no.10
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• pp.1247-1256
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• 2010

Since biodiesel as bioenergy is defined as ester compounds formed by esterification of animal/vegetable oils, in this study three vegetable cooking oils (market, waste and refined waste ones) were esterified by reactions of alkali catalyst and immobilized enzyme. The fatty acid composition of the formed ester compounds was analyzed to investigate the feasibility of biodiesel production. By lipolysis (i.e, hydrolysis of Triglyceride (TG)), all three vegetable oils used in this study were found to produce Diglyceride (DG), Monoglyceride (MD) and Fatty acid ethylester (FAEE). However, the amount of produced FAEE (which can be used as an energy source) was in the increasing order of market cooking oil, waste one and refined waste one. With NaOH catalyst, FAEE was produced about 24.92, 17.63 and 11.31 % for the respective oils while adding Lipozyme TL produced FAEE about 43.54, 38.16 and 24.47 %, respectively. This indicates that enzyme catalyst is more effective than alkali one for transesterification. In addition, it was found that the composition of fatty acids produced by hydrolysis of TG was unchanged with alkali and immobilized enzyme reactions. Thus it can be expected that stable conditions remain in the course of mixing with gasoline whose composition is similar to that of the fatty acids.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.725-729
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• 1991

Unsaturated all-cis-5,8,11,14-eicosatetraenoic(arachidonic), 7,10,13-hexadecatrienoic, 10, 13-octadecadienoic acid ethyl ester and a lot of chimyl alcohol were isolated along with common 9-hexadecenoic acid ethyl ester from marine mollusca Bullacta exarata collected from sangnackworl island in the Korea sea. In addition, cholesterol and its fatty acid ester were obtained. Their structures were deduced from $^1H-$and $^{13}C$-NMR, GC-ms, and FT-IR spectra.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.532-535
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• 2009

In this study, the fatty acid methyl ester was prepared from the vegetable oil by inducing ultrasound energy. The ultrasound energy was applied to the esterification reaction for heating and stirring effects. Ultrasonic induction results in the shortened reaction time and brings the increase of the methyl ester yield. However, the continuous introduction of ultrasound during the esterification reaction results in temperature increase, then the over-heating of reaction temperature was ineffective. Therefore, the system temperature was controlled at constant temperature state with the cooling circulation. The ultrasound induction reaction had the fatty acid methyl ester yield of 93% at the reaction time was 30 minutes, faster than the traditional esterification process.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2333-2341
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• 2017

Mineral oils are commonly used as transformer insulation oils but these oils are obtained from non-renewable and non-sustainable sources, which is highly undesirable. For this reason, natural ester oils are now being used in replacement of mineral oils because of their good biodegradability, high cooling stability, good oxidation stability and excellent insulation performance. Nanotechnology has gained prominence in both academic and industrial fields over the years and it has been shown in previous studies that nanoscale materials are useful for transformers due to their favourable dielectric properties. The objective of this study is to compare the AC breakdown voltage and viscosity of natural ester oil with three types of nanofluids. The natural ester oil-based nanofluids are prepared by mixing palm fatty acid ester (PFAE) oil with three types of nanoparticles at a concentration of 0.01 g/l: (1) $Fe_3O_4$ conductive nanoparticles, (2) $TiO_2$ semi-conductive nanoparticles and (3) $Al_2O_3$ insulating nanoparticles. The AC breakdown voltage of the oil samples is analysed using Weibull statistical analysis and the results reveal that the PFAE oil-based $Fe_3O_4$ nanofluid gives exceptional dielectric performance compared to other oil samples, whereby the AC breakdown voltage increases by 43%. It can be concluded that the PFAE oil-based $Fe_3O_4$ nanofluid is a promising dielectric liquid to substitute mineral oils.

• Tribology and Lubricants
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• v.30 no.1
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• pp.52-58
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• 2014

Because food crops serve as the raw materials for biodiesel, the increasing use of biodiesel as an alternative fuel can lead to adverse effects such as food price inflation and may contribute to global starvation. To solve these problems, efforts are being made to explore various nonedible raw materials for producing biodiesel. Different raw materials impart different fuel characteristics to biodiesel. In this study, we synthesized pure fatty acid methyl ester (FAME), which is a biodiesel component, and then analyzed its fuel properties. The fuel properties of pure FAME would be useful in producing biodiesel from various new raw materials.

• Applied Biological Chemistry
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• v.29 no.4
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• pp.346-351
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• 1986

This study was carried out to investigate the changes in bound, free, and neutral lipid components of malt during malting, two-rowed barley. During malting, the temperature and relative humidity were $17^{\circ}C$ and 80%, respectively. The content of free lipids in both two-rowed barley and their malt was much higher than that of bound lipids. Decrease in the content of free lipids during malting was more prominent than that of bound lipids. The content of neutral lipids was 21.0mg/g-d. w. out of 27.9mg/g-d. w. of total lipids extracted from two-rowed barley. The content of neutral lipids decreased during malting. Triglyceride, free fatty acid and sterol ester were the principal components of neutral lipids. The content of triglyceride decreased during malting, but the content of free fatty acid and sterol ester increased. Linoleic, palmitic, oleic and linolenic acid were the principal fatty acid of free and bound lipids. The content of palmitic acid in free lipids increased during malting, but that of bound lipids decreased. The content of oleic acid in free lipids decreased. The principal fatty acids of neutral lipids were similar to those of free lipids. The content of palmitic acid increased during malting, but that of linoleic and stearic acid decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.555-560
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• 1994

In order to observe the effects of the fees mixed with the lard and two vegetable seed oils on the fatty acid compositions of liver and brain tissue, the oils mixed with 2.5% lard and various levels of perilla oil and evening primrose oil were administered to the male rats of the Sprague-Dawley for 4 weeks . In the fatty acid composition of liver lipid, saturated fatty acid (SFA) contents were rich in the phopholiipide and cholesteryl ester fraction. Monounsaturated fatty acid (MUFA) contents were rich in the triglyceride fraction and polyunsaturated fatty acid (PUFA) contents were rich in the phospholipid fraction. In the fatty acid composition of liver lipid fractions, according as the contents of mixed perilla oil decreased and the contents of mixed evening primrose oil increased , n -3 PUFA contents tended to decrease and n-6 PUFA contents tended to increase. Fatty acid composition of liver lipid fractions were influenced from the fatty acid composition of the test lipids. In the fatty acid composition of brain phospholipd, PUFA contents (40%) were rich and according as the contents of mixed evening primrose oil increased, the ratio on n-3/n-6 PUFA and eicosapentaenoid acid (EPA) /arachidonic acid (AA) tended to slightly decrease.