• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.307-313
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• 1998

This paper presents the experimental results of the friction characteristics of double lip-type oil seals which show an improvement in sealing performance over single lip-type oil seals. The major differences between two oil seals are the number of contact lip and seal materials; Nitrile Butadine Rubber(NBR) and urethane rubber. The measured results show that the friction torque of double lip seals shows 12-17% increases compared with those of single lip-type seals. But the sealing performance and service life of double tip oil seals have been increased and stabilized due to an optimized design of the seal lip and material properties.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2008년도 춘계학술발표회
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• pp.117-120
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• 2008

금번 태안 해안에서 발생한 해상 기름유출 사고에서도 탈 수 있듯이 유출유는 시간이 경과함에 따라하고 고점도화 되어 타르 형태의 기름찌꺼기로 변화하고 조류를 따라 이동하다 수온이 높아질 경우 그 점도가 낮아져 주변해역에 유막을 형성하는 과정을 반복하기 때문에 조류가 미치는 넓은 범위를 지속적으로 오염시키는 요인이 되고 있다. 지금까지 해상에서 타르 형태의 기름찌꺼기를 수거하는 방법은 개인이 쪽대를 이용하여 회수하는 형태로, 넓은 범위에 걸쳐있는 기름찌꺼기가 해안으로 밀려들기 전에 제거하기는 한계가 있다. 본 연구는 이러한 기름찌꺼기를 효율적으로 수거한 수 있는 방안을 찾고자 기름찌꺼기의 흡착성을 이용 한 붐 형태의 흡착 매트와 기 보고한 Net형 부유 폐기물수거기구를 이용하여 태안 기름유출 사고 현장에서 그 가능성을 시험한 것이다. 그 결과 Net형 수거기구는 개인의 수작업으로 수거작업을 했을 때에 비해 단시간에 훨씬 높은 수거성능을 보여 타르성 기름찌꺼기 수거기구로 이용할 수 있음을 확인할 수 있었다.

• 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 Nutrition and Health
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• 제39권6호
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• pp.560-571
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• 2006

The purpose of this study was to determine composition of food groups appropriate for the evaluation of the quality of total diet or food guide, using the data from the 1998 National Health and Nutrition Survey. Twenty-four-hour-dietary recalls of total 1,110 Korean adolescents aged 13 - 19 years (male 543, female 567) were analyzed for food group consumed (Dietary Diversity Score, DDS), intake patterns of food group, mean index of nutritional quality (mINQ) and nutrient adequacy ratio (NAR). Considering Korean food pattern different from the Americans, this study is to check if Korean 5 food groups with both of oil & sugar group and vegetable & fruit group, and a minimum amount of 30 g in grain group and 15 g in meat group modified from Kant's minimum amount, 15 g in grain and 30 g in meat, could also be appropriate for the diet evaluation of Korean adolescents. Combination of food group and minimum food intake per each food group used in the first trial were categorized into 6 kinds of types: 1) American 5 food groups with Kant's minimum amount as control or 2) American 5 food groups with modified Kant's minimum amount 3) Korean 5 food groups excluded by sugar with the modified amount 4) Korean 5 food groups with modified amount 5) American food groups added oil group with the modified amount 6) American food groups added oil & sugar group with the modified amount. In case of oil group or oil and sugar group, 5 g was quoted for the minimum amount. Correlation between DDS and indices of other diet quality in each type of food group composition were analyzed and the best food group composition was traced by comparing the correlation coefficients of DDS and mINQ or MARs at ${\alpha}\;<\;0.01$. There was no meaningful difference in weight length index of the subjects of eating or not-eating oil or oil & sugar, while the values of mINQ showed higher in the subjects eating oil but no difference in the subjects eating oil & sugar, compared to the group not-eating, respectively. In comparison of type 1 and type 2, correlation between DDS and indices of other diet quality showed higher in type 1 using Kant's amount. And comparing the type of a combined group of fruit & vegetable (type 3 and 4) and the type of separated group of fruit and vegetable (type 5 and 6). six groups of separated vegetable and fruit showed the higher correlation of DDSs and indices of diet quality. In case of being classified into six groups with oil, DDS showed correlation of r = 0.293 with INQ. While, being classified into six groups with oil & sugar instead of oil only, DDS showed correlation of r = 0.249 with INQ. Accordingly the type 5 with oil is regarded as the better food group type than the type 6 with oil & sugar. Since better result was shown in the composition of six groups with Kant's minimum amount, the comparative analysis on both of type1 with oil and oil & sugar was finally performed. Then oil added type 1 showed higher correlation of DDS and indices of diet quality. These result indicated that it would be more appropriate to use six food groups with separate vegetable and fruit including oil group (oil-added type 1) rather than oil & sugar group for evaluation of dietary quality of Korean adolescents using DDS.

• Tribology and Lubricants
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• 제16권6호
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• pp.440-447
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• 2000

It's a tendency to strengthen related international laws as the importance on marine oil pollution recently becomes the issue. According to the regulation of IMO, oil discharge from ships is allowed under 15 ppm only and oil filtering equipment is essential. However, for large ships using heavy fuel oil of over S.G 0.98 and viscosity 380 cSt and system oil, it has been in difficulty to process with existing filtering type of oily water separator. Oily water pre-separator of laminated plate type which is one of gravity type separator has very simple structure and it also makes easier to maintain and repair. In another words, it fits well to process large amount of rich oil with high specific gravity. In this paper, oily water pre-separator of laminated plate type has been studied. The function of emulsified oil and 4 different types of oil have been analyzed and each character has been investigated and proved by experiments. As the result of it, the efficiency of separating oil water has been advanced by 10% in case equipped with pre-separator. In addition, the higher temperature is and the more laminated plate has, it turns out to be getting more effect.

• Journal of Biosystems Engineering
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• 제41권3호
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• pp.177-183
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• 2016

Purpose: Mee (Madhuca longifolia) is an economically important tree growing throughout Sri Lanka. Its importance is mainly attributed to its oil with high nutritional and medicinal values. However, an inefficient extraction method limits its use. This study revealed the possibility of extracting oil from mee seeds by using a screw-type oil expeller. Methods: A popular screw-type oil expeller was used in the experiment. Extract bar clearance and speeds of the main spiral shaft were altered to increase the oil expelling efficiency of the machine. The quality of refined oil at the optimum oil yield was determined by measuring the refractive index, saponification value, iodine value, unsaponifiable matter, free fatty acid, and specific gravity. Results: An optimum yield of 35% oil was obtained when the machine capacity was 30 kg/h and energy consumption was 0.13 kWh/kg. This optimum machine condition was observed at an extract bar clearance of 0.5 mm and a main spiral shaft speed of 90 rpm. The refractive index, saponification value, iodine value, unsaponifiable matter, free fatty acid, and specific gravity of the oil were 1.4, 203, 59, 3.5%, 0.2%, and 0.907 g/cm3 respectively. Color of the mee oil was closer to yellow, which is revealed by the lightness value (L) of 24.93 and positive value (b) of 11.81. Conclusion: The screw-type oil expeller can be used for economically extracting mee oil on a commercial scale.

• 한국약용작물학회지
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• 제12권6호
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• pp.459-462
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• 2004

이 연구는 국내 8개 지역에서 수집한 꽃향유의 정유성분을 분석하여 화학형을 분류하고, 이들 화학형 성분이 항산화 작용과 식품부패균을 억제하는 효과가 있는지를 알고자 하였다. 정유성분 분석결과 3개의 화학형으로 구분할 수 있었다. 화학형 1의 주성분은 dihydrotaketone (DT type)이었다. 개화기를 기준하여 꽃향유의 개체에 따라 naginatketone (NK type)이 60% 이상을 함유한 것과 elsholtziaketone (EK type)을 60% 이상 함유한 개체로 분류할 수 있었고, 또한 이들 두 성분은 종자세대 후에도 EK type은 elsholtziaketone이 주성분으로 나타났고 NK type은 naginataketone이 주성분인 것이 확인되었다. 따라서 NK type은 제2 화학형으로 그리고 EK type은 제3 화학형으로 구별하였다. 항산화 효과는 $6\;mg/{\ell}$ 농도에서 나타났으며, 같은 농도에서 DT>NK>EK 순으로 항산화능을 보였다. NK type은 Streptomyces와 Bicillus에서, EK type은 Streptomyces와 Pseudomonas에서 높은 항균능력을 보였다.

• Tribology and Lubricants
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• 제26권1호
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• pp.21-30
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• 2010

In this research, it is investigated the collecting efficiency of jet oil to several types of piston oil cooling gallery by using recently developed PCJ (piston cooling jet) rig tester. So it will be selected for a better design of piston oil cooling gallery. The collecting efficiencies at each type of piston cooling galleries are measured under conditions of a few piston positions, and several oil jet pressures and oil viscosities. Furthermore, the type of jet cone will be compared for a few jet pressure conditions. The selected type of piston oil cooling gallery is planned to be applied to the target engine which is now developing to satisfy the EURO VI emission regulation.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2159-2166
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• 2000

Recently, high performance machining center requires special type of sealing mechanism that prevent a leakage of oil jet or oil mist lubrication system. Sealing of oil-air mixture plays important r oles to have an enhanced lubrication for performance machining center. Current work emphasizes on investigations of the air jet effect on the protective collar type labyrinth seal. To improve sealing capabilities of conventional labyrinth seals, air jet is injected against the leakage flow. In this study, an adapted model is introduced to improve sealing capability of conventional non-contact type seals. It has a combined geometry of a protective collar type and an air jet type. Both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement. The sealing effects of the leakage clearance and the air jet magnitude aic studied in various parameters. Gas or liquid has been used as a working fluid for most of nori-contact types seals including the labyrinth seal. However, it is more reasonable to regard two-phase flows because oil mist or oil jet are used for high performance spindle's lubrication. In this study, working fluid is regarded as two phases that are mixed flow of oil and air phase. Both of turbulence and compressible flow model are also introduced in a CFD analysis to represent an isentropic process. Estimation of non-leaking property is determined by amount of pressure drop in the leakage path. Results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effect of the sealing improvement is explained as decreasing of leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger