• 한국정밀공학회지
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• 제21권2호
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• pp.21-26
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• 2004

The formed tool is used to machine the geometrical shape of bearing rubber seal efficiently. The bearing rubber seal has complex geometry for the complicated geometrical shape to prevent leakage of lubricant oil and influx of the dust effectively. Because it is difficult to machine the unique shape exactly by the conventional tool, the formed tool is used in machining a rubber seal die. In this paper, It is performed to investigate machining characteristic of the formed tool； cutting edge wear, cutting force, and surface quality. Also, an efficient precision machining condition is proposed, and the inspection results of rubber seal with CAI are discussed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.385-388
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• 1997

As the environmental regulations become stricter, new machining technologies are being developed which takes envi ronmenta 1 aspects into account . Since cut t ing oi I has some impact on environment. many researches are being carried out to minimize the use of cutting oi I. The methods for minimizing cutting oil usage includes the following techniques: I ) Cooling of tools and work piece. 2) Useage of compressed cooling air for the removal of chip. 3) Minimal useage of environment-friendly vegetable cutt:ngoiI for lubrication between chip and tools. Since the turning machine is continuous, tools are under constant thermal load and tool wear increases as the lubricative performance degrades. Also surface roughnesses have a direct influence on turning. In order to examine the characteristics of turningmachining, this work investigates experimentally the degree of tool wear and characteristics of surface roughness in relation to machining conditions, supply methods, and cooling methods.

• 반도체디스플레이기술학회지
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• 제16권3호
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• pp.20-24
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• 2017

For process improvement and cutting down on expenses in solar cell industry, it is necessary to improve recycling process of wafer manufacturing. In this research, a study is introduced to develop classifier which is for recycling of abrasive. First of all, recycling process of wafer manufacturing is analyzed. And then, 3 steps of experiments such as oil removal, impurities removal and classification were executed. For the classification of slurry, a classifier is designed and manufactured. From experiments, it is verified that ultra sound vibration and flux are very important factors for classification. By experiencing the recycling processes and making devices, the technique can be initiated industry if needed such as decreasing waste and cutting down on expenses.

• 한국기계가공학회지
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• 제18권5호
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• pp.48-52
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• 2019

A coolant pump is the device that cools processed articles and tools when using cutting, boring, and grinding machine tools and provides cutting oil for distributing or cleansing the cut chip to the worktable, processing position, etc. In particular, it consumes a large proportion of energy in machine tools, so it plays an important role in terms of energy efficiency. The purpose of this research is to optimize the shape of impeller, which directly affects performance improvements, to determine the capacity of the coolant pump. To do so, we carried out a parametric analysis with the geometric shape of the impeller as the input variable.

• 멤브레인
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• 제6권2호
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• pp.86-95
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• 1996

본 연구에서는1축 회전판형 한외여과막 모듈의 순수 투과율 예측모델과 기름 에멀션의 분리 특성 및 투과율 예측모델을 유도하였다. 1축 RDM은 한외여과막(UOP사, 직경 0.22m)으로 제작된 회전판막을 장착하여 $25^{\circ}C$에서 압력, 각속도($\omega$), 농도 변화에 따라 분리특성을 조사하였다. 회전판막의 각속도가 0에서 52.36rad/s로 증가할수록 회전판내 유체가 받는 원심력에 의한 압력 강하와 분리막 표면의 미끄럼 흐름에 의한 압력 강하로 순수 투과율은 최대 각속도에서 3.9% 감소하였다. 원심력과 미끄럼 흐름에 의한 압력 강하는 선속도(${\omega}r$)의 자승에 비례하였다. 회전판의 각속도가 52.36에서 2.62rad/s로 감소할 때 5% 절삭유의 투과율은 30.16% 감소하였고 농도가 낮을수록 막회전과 투과율에 미치는 영향은 적었다. 절삭유의 투과율(J; $kg/m^{2} \cdot s$)은 회전에 의한 압력 강하를 고려한 유효압력차($\Delta P_{T}$ ; Pa), 벌크농도($C_{B}$; %), 선속도($\omega$r; m/s) 등에 영향을 받으며 실험 결과에 저항 모델을 적용하여 다음과 같은 식을 유도하였다.

• 한국가스학회지
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• 제26권6호
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• pp.24-29
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• 2022

이 논문은 LPG 자동차의 캠축베어링 시일의 오일누설, 컴퓨터커넥터 핀 손상에 의한 접촉불량, 베이퍼라이저 배부불량으로 인한 고장사례에 대하여 현상을 분석, 연구한 것이다. 첫 번째 사례는 실린더 헤드를 분해하여 확인한 결과 타이밍 시스템에서 가까운 엔진의 흡기캠축의 베어링과 시일의 조립부 손상으로 인해 이 부위로 엔진오일이 누설되는 것을 확인하였다. 두 번째 사례는 엔진컴퓨터로 공급되는 자동차의 시동을 제어하는 전원선의 커넥터 핀이 손상되어, 전원이 공급되지 않아 시동이 꺼진 것을 확인하였다. 세 번째 사례는 베이퍼라이저 내부에 이물질의 퇴적으로 인해 가스의 흐름이 원활하지 못하여 엔진의 부조화현상이 발생되었다. 결국, 베이퍼라이저에서 믹서로 적은 양의 가스를 공급하게 되고, 믹서의 스로틀 열림량을 제어하는 컴퓨터는 그 열림량만큼 공기를 공급하게 됨으로써 연소실에서 혼합기는 희박한 상태가 되어 엔진의 적정출력을 내지 못하는 것을 확인하였다. 따라서, 자동차가 최적의 운전조건이 될 수 있도록 자동차관련 시스템의 관리를 철저하게 해야한다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권8호
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• pp.1252-1258
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• 2018

Objective: This study was carried out to determine the effects of cumin essential oil on the silage fermentation, aerobic stability and in vitro digestibility of alfalfa silages. Methods: Alfalfa was harvested at early bloom (5th cutting) stage in October and wilted for about 3 hours. The research was carried out at three groups which were the control group where no additive control was done (CON), cumin essential oil (CMN3) with 300 mg/kg and CMN5 with 500 mg/kg cumin essential oil addition. Alfalfa was ensiled in plastic bags. The packages were stored at $8^{\circ}C{\pm}2^{\circ}C$ under laboratory conditions. All groups were sampled for physical, chemical and microbiological analysis 120th day after ensiling. At the end of the ensiling period, all silages were subjected to an aerobic stability test for 7 days. In addition, enzimatic solubility of organic matter (ESOM), metabolizable energy (ME), and relative feed value (RFV) of these silages were determined. Results: pH level decreased in the cumin groups compared to CON (p<0.05), thus inhibiting proteolytic enzymes from breaking down proteins into ammonia. In addition, it increased ESOM amount, and concordantly provided an increase of ME contents. Similarly, dry matter intake and RFV ratio increased. After opening the silage, it kept its aerobic stability for three days. Conclusion: Cumin essential oil improved fermentation, and affected chemical and microbiological characteristics of silages. Especially the addition of 300 mg/kg cumin provided cell wall fractionation through stimulating the activities of enzymes responsible. It also increased the number and activity of lactic acid bacteria (LAB) through providing a development of LAB.

• Tribology and Lubricants
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• 제12권4호
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• pp.52-59
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• 1996

The results of the electrical contact conductivity of multi-contact spots accounting the surface roughness and the non-conductive films of different origins such as air, water, cutting oil, and machining oil are presented. The array of metal spheres compressed between two flat plates has been used for simulation of the contact behavior of multiple contact of solids, under normal loading. Measurement of electrical contact resistance has been made using the equipment providing the adequate accuracy in the range of micro Ohms. The data on electrical contact resistance have been compared with theoretical predictions using the multiple contact model of constriction resistance. The effect of single spot number and array on conductivity of contact has been evaluated. The results of the experiments show that the contact resistance are closely related to the number of loading cycles, form of surface roughness, and presence of non-conductive films that reduce the size of the real electrical contact spots.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 춘계 총회 및 학술발표회
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• pp.102-104
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• 1998

한외여과막을 이용한 수용성 절삭유의 재사용 1. 서론 : 최근 수용성 합성 금속 가공유의 시장 점유율이 급격히 확대되어 감에 따라서 환경오염문제가 심각하게 대두되고 있으며 특히, 금속 가공유의 용액내의 미생물의 번식을 억제하기 위하여 사용하는 biocide가 다량 방류될 경우 생태계의 미치는 영향이 지대할 수 있다. (생략)

• 농업과학연구
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• 제33권2호
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• pp.97-106
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• 2006

To strengthen the competitiveness of agricultural sector of the Korea, the direction of market trends on agriculture of the Malaysia was reviewed. The most dominating agricultural area in value is palm oil products, and forest products, sea products poultry products and rubber products is in order. The cultivated area of highest two top plants, oil palm and rubber, was about 4.4 million hectares in 2005, but it is decreasing year by year. Comparatively, rice field, pine apple and fruits tree cultivating area is increasing in tendency by the year. Among all the agricultural products, those items such as pork meat, poultry, egg were self-sufficient, rice, fruits, vegetables and sea products were about 70 to 80% self-sufficient, and beef meat, goat meat and milk were below 20% self-sufficient. Most of the grains, such as wheat, rice, barley, corn etc. and their processed food were imported. Also, temperate fruits such as apple, pear, and water cultivated as well as sprouting vegetables are imported. Ornamental products as cutting flowers and orchids are exported to mainly to the Singapore, but high quality temperate fruits and vegetables are imported from Australia. Oil palm exportation covers the balance of the other items imported and obtaining the foreign money as well in Malaysia.