• 한국응용과학기술학회지
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• 제6권1호
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• pp.9-14
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• 1989

Effectiveness of some natural antioxidants were investigated by measuring the physico-chemical charcteristics and fatty acid composition during thermal oxidation in palm oil. Tocopherol showed most enhanced thermal oxidation stabilities compared to the other natural antioxidants. AR spice was no good AOM stability and changes of acid value but the other parameters were obtained desirable results. The changes of linoleic aicd content was slightly decreased during thermal oxidation. Addition of rosemary and glycyrriza extract increased the stabilities of oil less than tocopherol and AR spice. Order of antioxdative effects was tocopherol, AR spice and others. There was no significiant difference in stability of rosemary and glycyrriza extract.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.380-386
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• 2020

This paper represents an analysis of the economic impact of firing natural gas/diesel and natural gas/by-product oil mixtures in diesel engine power plants. The objects of analysis is a power plant with electricity generation capacity (300 kW). Using performance data of original diesel engines, the fuel consumption characteristics of the duel fuel engines were simulated. Then, economic assessment was carried out using the performance data and the net present value method. A special focus was given to the evaluation of fuel cost saving when firing natural gas/diesel and natural gas/by-product oil mixtures instead of the pure diesel firing case. Analyses were performed by assuming fuel price changes in the market as well as by using current prices. The analysis results showed that co-firing of natural gas/diesel and natural gas/by-product oil would provide considerable fuel cost saving, leading to meaningful economic benefits.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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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.

• 보존과학회지
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• 제31권1호
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• pp.13-20
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• 2015

목조문화재는 수분의 영향으로 열화의 가속화가 진행되기 때문에 전통적으로 표면을 수분으로부터 차단하기 위해 들기름 및 동유와 같은 유지류를 도포하였다. 그러나 목조문화재에 적합한 유지류 코팅 방법 및 성능에 대한 체계적인 연구가 부족한 실정이다. 본 연구는 천연 유지류 3종과 오일스테인 2종의 목재의 방향별, 공시재의 시간 경과 및 유지류의 중탕 여부에 따른 방수 성능을 평가하여 현장 적용 가능성을 판단하였다. 건전 목재의 섬유방향에서 상온의 천연유지류 코팅제 방수성능은 대조군과 비교하여 약 79.2%를 차단하였으며, 특히 동유는 90.5%의 수분을 차단할 정도로 우수한 성능을 나타냈다. 2년간 실내에서 컨디셔닝을 실시한 경우 유지류의 방수 성능은 약 8.8% 감소하였다. 유지류를 중탕하여 사용할 경우 약 5.0%의 방수 성능이 향상되며, 특히 아마인유는 중탕하여 사용할 경우 약 9.6%의 방수 성능을 개선할 수 있다.

• 한국식품영양학회지
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• 제8권2호
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• pp.88-92
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• 1995

The antioxidant activity of synthetic antioxidants, BHA, BHT and TBHQ and natural antioxidants, rosemary extract, sesamol, caffeic acid and pyrogallol In a skip jack oil were studied. A control and substrates containing synthetic(0.02%) and natural antioxidant (0.05%) were stored in an incubator kept at 37$^{\circ}C$ for 8 days. The antioxidant activity of synthetic and natural antioxidants was investigated by comparing peroxide values. The results of this study were as follows All the synthetic antioxidants used for this study exhibited antioxidant activity in skip jack oils. The antioxidant activity of TBHQ was greater than that of BHA and BHT. The rosemary extract did not show antioxidant activity in skip jack oils. The antioxidant activity of sesamol and caffeic acid were greater than those of BHA. Especially Pyrogallol exhibited very strong antioxidant activity, comparable to that of the TBHQ. The antioxidant activity of the sesamol, caffein acid and pyrogallol used skip lack oil, In decreasing order as follows : pyrogallol>caffeic acid> sesamol.

• Natural Product Sciences
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• 제24권2호
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• pp.125-131
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• 2018

Berries and branches essential oil of Juniperus phoenicea were obtained by electromagnetic induction heating assisted extraction and by hydrodistillation with a yield varied from ($1.2{\pm}0.3$ to $2.4{\pm}0.7%$) and from ($0.6{\pm}0.1%$ to $1.1{\pm}0.1%$), respectively. forty eight compounds were identified representing (97.2 - 99.7%) of the oil. ${\alpha}$-Pinene (40.3 - 67.8%) and ${\delta}$-3-carene (13.5 - 26.8%) were the main compounds in berries and branches essential oils. Antioxidant activity was evaluated by three means: inhibition of 2, 2-diphenyl-1-picryl hydrazyl (DPPH) free radical, reducing power and ${\beta}$-Carotene/linoleic acid bleaching. The antioxidant activity of essential oils showed $IC_{50}$ ranging from $67.6{\pm}1.02{\mu}g/mL$ to $131.5{\pm}0.8{\mu}g/mL$ for berries and from $98{\pm}1.25{\mu}g/mL$ to $166.8{\pm}0.29{\mu}g/mL$ for the branches. Berries oil show more potent antioxidant activity compared to branches. This result is supported by the three methods investigated in this work.

• Ocean and Polar Research
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• 제23권1호
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• pp.51-62
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• 2001

The Arctic consists of numerous sedimentary basins containing voluminous natural resources and two of the world's major oil and gas producing areas. The western Siberia Basin in the Arctic region has the largest petroliferous province with an area of 800 ${\times}$ 1,200 km and produces more than 60% of total Russian oil production. The North Slope of Alaska produces about 20% of the U.S. output, i.e., 11% of the total U.S. consumption. Being small compared to those regions, the Canadian Northwest Territories and the Pechora Basin in Russia produce only fair amount of oil and natural gas. There are also many promising areas in the northern continental shelf of Russia. In addition to Russia, Svalbard and Greenland have been investigated for oil and gas. Gas hydrates are widespread in both permafrost regions and arctic continental shelf areas. The reserves of gas hydrates in the Arctic Ocean are about 20${\sim}$32% of total estimated amounts of gas hydrates in the world ocean. Mineral mining is well developed, especially in Russia. The major centers are located around the Kuznetsk Basin and Noril'sk. They are major suppliers of gold, tin, nickel, copper, platinum, cobalt, iron ore, coal as well as apatite. There are also some minings of lead-zinc in Alaska and Arctic Canada.

• Journal of the Korean Wood Science and Technology
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• 제49권5호
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• pp.471-481
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• 2021

This study investigated the hygroscopicity and UV deterioration characteristics of 3 domestic and 4 imported woods using natural oil, stain, and varnish paints. In terms of hygroscopicity, it was found that the hygroscopicity of the painted wood was lower than that of the unpainted wood, and that as the number of coatings increased, the hygroscopicity decreased. In terms of anti-absorption, oil-based chemical paints showed higher resistance than water-based paints, and natural oils showed results comparable to oil-based paints. As for the UV deterioration, the amount of color change of the painted wood was lower than that of the unpainted wood, and there was no significant difference according to the number of times of painting. The amount of color change was found to be low in oil-based paints and hardwoods. Through this study, we confirmed effective moisture blocking and small color changes during painting using paints, and it is believed that wood can be protected from internal and external defects through selective and efficient painting based on data for excellent painting performance.

• Plant Resources
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• 제6권3호
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• pp.183-187
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• 2003

Two kinds of Angelica belong to Umbelliferae collected, the one is Angelica gigas that is inhabitant in Korea and the other is Angelica acutiloba that is indigenous in Japan at the field of Snyder Research and Extension Farm Rutgers University, New Jersey and was analyszed by GC and GC/MS. The composition of the essential oil of the different aerial parts of the Angelica has been studied. The oil yields obtained upon hydrodistillation were 0.18% (v/w) in Korean Angelica and 0.44% (v/w) in Japanese Angelica on dry root weight basis. By the growing stage in the Rutgers greenhouse condition, leaf and root of essential oil content a little decreased on 9 months later than 4 months later except for Angelica gigas leaf. Both of Angelica showed that amounts of essential oil content presented in order of leaf > petiole > root according to different plant part. The analysis of the essential oil from Angelica root led to the identification of 14 constituents totaling 64% in Korean Angelica and 13 constituents totaling 68% in Japanese Angelica. The major constituents of the Angelica root essential oil were ligustilide (47 %) and gamma terpi (14 %) in Korean Angelica, and alpha pinei (32 %) and nonane (25 %) in Japanese Angelica

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.716-723
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• 2006

A biosurfactant-producing bacterial strain was selected from oil-contaminated soil because of its ability to degrade crude oil and tributyrin $(C_{4:0})$. The strain was identified as Bacillus subtilis A8-8 based on its morphological, biochemical, and physiological characteristics. When B. subtilis A8-8 was grown with crude oil as the sole carbon source, the biosurfactant from the strain emulsified crude oil, vegetable oil, and hydrocarbons. Soybean oil was the optimum substrate for the emulsifying activity and emulsion stability of the biosurfactant, both of which were superior to those of several commercially available surfactants. The biosurfactant was purified by a procedure including HCl precipitation, methanol treatment, and silica-gel chromatography. The partially purified biosurfactant was analyzed by TLC (thin-layer chromatography), SDS-PAGE, and HPLC and it reduced the surface tension of water from 72 mN/m to 26 mN/m at a concentration of 30 mg/l. Therefore, the purified lipopeptide biosurfactant has strong properties as an emulsifying agent and acts as an emulsion-stabilizing agent.