• KSTLE International Journal
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• 제7권2호
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• pp.35-44
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• 2006

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. 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 inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure, then the friction and load of journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

• Tribology and Lubricants
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• 제23권5호
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• pp.207-218
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• 2007

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. 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 inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure distribution, then the friction in a journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

• Journal of Biosystems Engineering
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• 제37권6호
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• pp.429-433
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• 2012

Purpose: While rapeseed oil, soy bean oil, palm oil and waste cooking oil are being used for biodiesel, the viscosity of them should be lowered for fuel. The most widely used method of decreasing the viscosity of vegetable oil is to convert the vegetable oil into fatty acid methyl ester but is too expensive. This experiment uses ultrasonic energy, instead of converting the vegetable oil into fatty acid methyl ester, to lower the viscosity of the waste cooking oil. Methods: For irradiation treatment, the sample in a beaker was irradiated with ultrasonic energy and the viscosity and temperature were measured with a viscometer. For heating treatment, the sample in a beaker was heated and the viscosity and temperature were measured with a viscometer. Kinematic viscosity was calculated by dividing absolute viscosity with density. Results: The kinematic viscosity of waste cooking oil and cooking oil are up to ten times as high as that of light oil at room temperature. However, the difference of two types of oil decreased by four times as the temperature increased over $83^{\circ}C$. When the viscosity by the treatment of ultrasonic energy irradiation was compared to one by the heating treatment to the waste cooking oil, the viscosity by the treatment of ultrasonic energy irradiation was lower by maximum of 22% and minimum of 12%, than one by the heating treatment. Conclusions: Ultrasonic energy irradiation lowered the viscosity more than the heating treatment did, and ultrasonic energy irradiation has an enormous effect on fuel reforming.

• Ocean and Polar Research
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• 제40권4호
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• pp.271-280
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• 2018

The purpose of this study is to examine the causal relationship among oil consumption, oil-tanker accidents, and economic growth, and to derive policy implications from the results. Therefore, this paper attempts to analyze the short term, long term, and strong causality factors pertaining to the relationship between oil consumption, oil-tanker accidents, and economic growth in Korea using time-series techniques and annual data for the 1984-2016 period. Tests for unit roots, co-integration, and Granger-causality based on an error-correction model are presented. The results show that bidirectional causality exists between oil consumption and oil-tanker accidents, between economic growth and oil consumption, and between oil-tanker accidents and economic growth. The study shows that oil was used as a core energy source during the rapid economic growth of Korea in the past, and that this caused the number of oil-tanker accidents to rise as oil consumption increased.

• 무역학회지
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• 제44권6호
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• pp.105-118
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• 2019

In the past two decades, due to the rapid fluctuations in the oil supply and demand in Northeast Asia as well as a surge in oil prices in the early 2000s, Korea has been developing the Northeast Asia Oil Hub project as a national project. This project was promoted based on the policy consideration that the nation's energy security and regional development can be promoted by establishing an oil hub in Northeast Asia that can eventually replace Singapore as East Asia's oil logistics hub. Following the construction of a large-scale oil storage facility in Yeosu in 2013, the main project in Ulsan has suffered many difficulties due to environmental changes such as the supply and demand of oil and political factors. The survey, which investigated the performance, problems, and prospects of the oil hub project, illustrates that scores of all sectors are of average level. In terms of performance and prospects, policies such as facility investment, law, and system improvement were determined to be rather high while operational areas such as value-added activities, profitability, and marketing activities were perceived as having more serious problems by respondents. In conclusion, despite the strong potential of Korea's oil hub based on its geographical location, facilities, and oil product capacity, there are problems related to policies, institutions, and investment. In the future, the oil hub business should be reviewed by considering environmental factors, and a drastic improvement plan for attracting foreign investors and oil traders should be established.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.539-543
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• 2001

Almost all rotating machinery has bearings. Bearing is one of the most important part of rotating machinery. Vibration of rotating machinery depend on its bearing conditions. Bearing conditions are followings ; oil gap, bearing type, bearing temperature, bearing oil condition. Especially, bearing oil condition influences on rotating machinery vibration directly. In this paper we have discussed the abnormal vibration of turbine due to oil condition. oil whip problem was occured in the certain power plant. and we had sloved this problem through the control of operating values and alignment.

• Journal of Animal Science and Technology
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• 제49권1호
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• pp.51-58
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• 2007

본 연구는 fish oil의 첨가가 한우거세우의 증체, 배최장근의 지방산 조성 및 도체등급에 미치는 영향을 구명하고자 평균체중 440.8±32.4kg의 한우거세우 20두를 공시하여 실시하였다. 시험구 배치는 fish oil을 첨가하지 않는 FO-0구와 fish oil을 3% 첨가하는 FO-3구의 2처리로 하였다. 총 증체량과 일당증체량은 fish oil의 첨가에 관계없이 비슷한 결과를 보였다. Fish oil의 첨가는 배최장근의 단백질, 지방 및 회분 함량에 영향을 미치지 않았다. 배최장근의 isoleucine 및 glycine 함량은 fish oil의 첨가로 감소되었으나(p<0.05), cystein 함량은 증가되었다(p<0.05). Fish oil의 첨가는 배최장근의 myristic acid 및 eicosenoic acid 함량은 감소시켰으나(p<0.05), oleic acid 및 arachidonic acid 함량은 증가시켰다(p<0.05). 또한 배최장근의 EPA 및 DHA 함량은 fish oil의 첨가로 증가되었다(p<0.05). 도체중, 등지방두께, 배최장근단면적, 육량지수 및 육량등급은 fish oil의 첨가에 관계없이 두 처리구간에 유사한 경향을 보였다. 육색은 fish oil의 첨가로 개선되었으며 (p<0.05), 육질 1등급 이상 출현두수는 fish oil의 첨가로 증가하는 결과를 보였다. 따라서 본 연구의 결과에서 한우거세우에 대한 fish oil의 첨가는 쇠고기의 지방산 중에서 풍미 및 기호성에 관여하는 oleic acid 함량, 인간의 건강과 관련이 있는 EPA 및 DHA 함량 및 육질 1등급 이상 출현두수를 증가시키는데 효과적인 것으로 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권7호
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• pp.1035-1040
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• 2003

This experiment was conducted to investigate the effects of fat sources on growth performance, nutrient digestibility, serum traits and intestinal morphology in weaning pigs. A total of 128 weaning pigs (Landrace${\times}$Large White${\times}$Duroc, $21{\pm}2$ days of age, $5.82{\pm}0.13kg$ of average initial body weight) were allotted in a randomized complete block (RCB) design with four treatments: 1) corn oil, 2) soybean oil, 3) tallow and 4) fish oil. Each treatment had 8 replicates with 4 pigs per pen. During phase I period (d 0 to 14), pigs fed corn oil or soybean oil diet tended to show higher ADG and FCR than any other treatments although there was no significant difference. During phase II period (d 15 to 28), pigs fed corn oil diet showed better ADG and ADFI than pigs fed soybean oil, tallow or fish oil. For overall period, growth performance of weaning pigs was improved (p<0.05) when pigs were fed soybean oil or corn oil. Apparent digestibility of energy and fat was improved when pigs were fed corn oil diet (p<0.05). Supplementation of corn oil resulted in higher serum triglyceride concentration than the other treatments (p<0.05). However, there was a lower cholesterol concentration when corn oil was provided compared to tallow or fish oil. Pigs fed corn oil tended to have increased villus height compared with soybean oil, tallow or fish oil treatment (p<0.05). This experiment suggested that vegetable oils such as corn oil or soybean oil, were much better fat source for improving growth performance of weaning pigs.

• 한국산학기술학회논문지
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• 제17권6호
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• pp.687-692
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• 2016

엔진에 터보차져를 사용하게 되면 엔진의 출력도 향상되지만 동시에 엔진의 온도도 높아지게 된다. 특히 피스톤의 경우는 냉각이 문제가 된다. 이러한 문제를 해결하기 위하여 오일 젯을 사용하는데, 오일 젯은 오일을 피스톤의 밑 부분에 분사하여 피스톤을 냉각시키는 것이다. 오일 젯이 사용된다면, 오일의 분사로 인하여 오일 유량의 증가및 피스톤으로부터의 열전달에 의하여 높아진 오일 온도 문제를 해결하기 위하여 오일 펌프 용량 증대와 오일 쿨러의 사용이 필요하다. 그러나 용량 증대 오일 펌프와 오일 쿨러를 사용하면 엔진의 마찰 토크가 증가하는 원인이 된다. 본 연구에서는 오일 젯, 오일 쿨러 및 오일 펌프의 용량 증대로 인하여 엔진의 마찰 토크가 증가하는 정도에 대하여 연구하였다. 또한 각 부품의 사양을 변경함에 따라 마찰 토크가 얼마나 영향을 받는가도 측정되었다. 저속에서는 오일 펌프와 오일 쿨러에 의한 영향이 크고 고속에서는 오일 쿨러에 의한 영향이 큼을 알 수 있었다.

• 한국식품조리과학회지
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• 제27권3호
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• pp.39-49
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• 2011

This study was conducted to evaluate the effects of adding unrefined oil on the antioxidant activity of a tuna oil-enriched emulsion by determining DPPH radical scavenging activity, reducing power, and inhibition of low-density lipoprotein (LDL) oxidation in vitro. The emulsion consisted of tocopherol-stripped canola (18.3 g) and tuna (9.1 g) oil, one of the unrefined oils (4.6 g), such as extra virgin olive, mustard, perilla, or sesame oil, 0.5% acetic acid (64 g), and egg yolk powder (4 g). The control emulsion contained only canola (21.4 g) and tuna oil (10.6 g), as oil sources,with the same composition of the remaining ingredients. The emulsion with added unrefined oil, particularly mustard oil, showed higher radical scavenging activity and reducing power than those of the control emulsion. The radical scavenging activity and reducing power of the emulsion with added unrefined oil were higher at 1,000 ppm than at 500 ppm thus, the effect was concentration-dependent. Adding sesame or perilla oil to the tuna oil-enriched emulsion resulted in higher inhibition of LDL oxidationwhereas adding olive oil increased LDL oxidation. The results clearly showed that adding roasted mustard, sesame, or perilla oil improved the antioxidant activity of a tuna oil-enriched emulsion by increasing free radical scavenging activity, reducing power, and inhibiting LDL oxidation. The results also suggest that adding unrefined oils produces a healthier fish oil-enriched salad dressing recipe.