• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.95-96
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• 2002

The operation of proceeding bearing in the conditions of misaligned axis of proceeding and bush leads to the load concentration on the bearing edges causing further mixed lubrication conditions, unstable operation and intensive wear of mating parts. For the design process of proceeding bearing the knowledge of static characteristics determined from the oil film pressure and temperature distribution is very important. For the 3-lobe proceeding bearing, the pressure, temperature and viscosity fields, load capacity, minimum oil film thickness, power loss, oil flow and maximum oil film temperature have been determined by iterative solution of the Reynolds', energy and viscosity equations. The paper introduces the results of theoretical investigations of static characteristics of 3-lobe proceeding bearing operating at misaligned axis of proceeding and bush. An effect of misalignment ratio, length to diameter ratio of the proceeding bearing, the lobe clearance ratio on the static characteristics was investigated. Laminar, adiabatic model of oil film for the solution of Reynolds, energy and viscosity equations was applied.

• 한국해양공학회지
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• 제15권2호
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• pp.1-5
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• 2001

A study on the new active type oil-water separation system including the oil-water separation system of magnetic film was carried out. Separation system is composed of several active types of circulating oil separation steps and one magnetic film separation step at final stage. At the magnetic separation step, ferrofluid easily forms a weak magnetic mixture with oil, which is from the water by magnetic field gradient. The vessel has been designed to run at the maximum speed of 25 knots. And two typical forms of SWATH and Catamaran have been studied as a new type of oil recovery vessel.

• Tribology and Lubricants
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• 제2권1호
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• pp.53-60
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• 1986

The methods to prevent or suppress the initial failure of the sliding surfaces by the formation of the protection film during the manufacturing process were studied. Now it has been known that the surface protection film which was formed during the running-in process is mainly $Fe_3O_4$ and its film was formed only at the limited oxygen ability during the lubricated sliding. So it was tried to form the same oxide film before the sliding by heat treatment at 300$\circ$C with the wetted specimen by oil. The results show that a thin oxide film ($Fe_3O_4$) was formed on the surface beneath the solid oil film and the specimen with this film has much better friction properties than those prepared with heat treatment at 500$\circ$C and 700$\circ$C or the original one.

• Tribology and Lubricants
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• 제16권2호
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• pp.114-120
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• 2000

This paper reports on the theoretical analysis on the lubrication characteristics between the piston ring and the grooved cylinder liner. The circular shape piston ring and two types grooves are consider, and the minimum oil film thickness during the full engine cycle are obtained by using iterative technique. The comparative results of minimum oil film thickness and viscous friction force between the smooth and grooved liner are presented. And various design parameter of piston ring and liner groove are tested. The groove in the liner generally reduces the minimum value of minimum oil film thickness, but the maximum viscous friction force is increased at the minimum film position.

• 한국응용과학기술학회지
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• 제11권2호
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• pp.17-38
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• 1994

Oil and fats has been using as the important raw materials in the coating industry from ancient time to date. This article was prepared with the aim of helping to the forward development trend for coating uses of oil and fats, as understand together the history using oil and fats for coatings, composition and classification coatings, types and composition of oil and fats using for coatings nowaday, how to use oil and fats for coating, film for coatings, film forming mechanism.

• 한국산학기술학회논문지
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• 제11권9호
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• pp.3119-3124
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• 2010

본 논문은 엔진 베어링에서 크랭크샤프트의 경사도를 고려했을 때와 고려하지 않았을 때 유막 동적거동을 컴퓨터 시뮬레이션을 이용하여 해석하였다. 본 해석은 탄성유체윤활 이론을 바탕으로 하여 최소유막의 동적특성을 수치적으로 해석하였다. 유막설계에 매우 중요한 인자인 크랭크샤프트 경사도를 고려하기 위하여 크랭크샤프트와 엔진베어링을 탄성체로 모델링 하였다. 유막거동해석을 위한 경계조건으로는 엔진 베어링에서 발생하는 비선형 구속력과 굽힘 모멘트를 고려하였고 이에 따른 크랭크샤프트의 경사도 영향을 고려함으로써 좀 더 실제 현상과 유사한 모델링을 수행하였다. 해석결과 엔진 베어링의 성능에 가장 큰 영향을 미치는 최소유막두께가 크랭크샤프트의 경사도를 고려하지 않았을 때보다 고려하였을 때 16%에서 24%정도 감소하는 것을 알 수 있었다. 또한, 해석결과에서와 같이 크랭크샤프트 경사도 증가는 최소유막두께의 감소를 유발하고 이에 따른 베어링 파손을 예측할 수 있었다. 따라서 본 논문의 해석결과가 자동차 엔진 베어링 설계 시 매우 유용한 자료로 사용될 것으로 사료된다.

• Tribology and Lubricants
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• 제14권3호
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• pp.87-93
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• 1998

Crank pin bearing in two-stroke marine diesel engine is operated under quite severe conditions since the elements are big and heavy and the sliding speed is very slow. Therefore it is very difficult to form oil film. In this paper, two types of bearings with different groove shape are compared. One has circumferential oil groove at lower position and the other has lengthwise oil groove at upper position. Bearing clearance, oil inlet pressure and length to diameter ratio are selected as design parameters. Locus of journal center and minimum oil film thickness are investigated to compare two cases.

• Tribology and Lubricants
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• 제11권4호
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• pp.53-57
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• 1995

The contact pressure behavior is examined by means of a finite element analysis. The oil film between the piston ring and cylinder liner is analyzed on the basis that it behaves like a polymer material. The calculated results indicate that a shape of sloping edge with a straight line, which is designated as a Model III, shows a good performance on the contact pressure behavior for the increased speed. Obviously, the ring face profiles play an important role on the contact pressure between compression ring and oil film.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.578-583
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• 1997

Abstract-Crosshead bearing in two-stroke marine diesel engine is operated under quite severe condition since the load on the bearing is sybject to the loading in a unidirectional and the sliding speed is very slow and oscillatory. So it is very difficult to form oil film and maintain the load. In this paper, two types of bearing are compared. One has large sized oil pocket and the seleted as multi-small oil grooves. Bearing clearance, oil inlet oressure and bearing types are selected as analysis parameters. Loci of journal center are presented to compare several cases. It is found that bearing clearance and shape affect to minimum film thickness.

• 한국축산식품학회지
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• 제43권6호
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• pp.1128-1149
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• 2023

In order to extend the shelf life of refrigerating raw lamb by inhibiting the growth of microorganisms, preventing the oxidation of fat and protein, and absorbing the juice outflow of lamb during storage, an active packaging system based on plastic/gelatin bilayer film with essential oil was developed in this study. Three kinds of petroleum-derived plastic films, oriented polypropylene (OPP), polyethylene terephthalate, and polyethylene, were coated with gelatin to make bilayer films for lamb preservation. The results showed significant improvement in the mechanical properties, oxygen, moisture, and light barriers of the bilayer films compared to the gelatin film. The OPP/gelatin bilayer film was selected for further experiments because of its highest acceptance by panelists. If the amount of juice outflow was less than 350% of the mass of the gelatin layer, it was difficult for the gelatin film to separate from lamb. With the increase in essential oil concentration, the water absorption capacity decreased. The OPP/gelatin bilayer films with 20% mustard or 10% oregano essential oils inhibited the growth of bacteria in lamb and displayed better mechanical properties. Essential oil decreased the brightness and light transmittance of the bilayer films and made the film yellow. In conclusion, our results suggested that the active packaging system based on OPP/gelatin bilayer film was more suitable for raw lamb preservation than single-layer gelatin film or petroleum-derived plastic film, but need further study, including minimizing the amount of essential oil, enhancing the mechanical strength of the gelatin film after water absorption.