• 해양환경안전학회지
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• 제7권2호
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• pp.1-11
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• 2001

Many investments and works being continued to preserve green ocean in each countries of the world. Especial1y, the researches on the prevention of marine oil pollution being strengthened. It is not easy to disclose sludge oils that were produced necessarily in the ships operation, so that they are transferred to shore treating facility after collected inside the ship＇s sludge tank mostly. However, this shore transferring method is not only costly and time consuming but also entails risk of oil pollution. In this regard, it will be the best way to manage the sludge oils inside ship itself. The purpose of this study is to device an ultrasonic breaking systems which recycle the sludge oil from ships into usable oil to be burnt. In this paper, the first place, matrix structures of sludge fuel oil(SFO) and sludge lubricating oil(SLO) with the irradiation time for ultrasonic vibrator were interpreted. And, erosion damage for vibrator horn tip which is one of important part of ultrasonic breaking systems was examined under such an environment of the sludge oils. The material for horn tip is being made of SS41 steel and its erosion phase was investigated with variation of the vibration amplitude of 50${\mu}{\textrm}{m}$ and 24${\mu}{\textrm}{m}$ as well as the change of temperature in the oil environments. It is suggested that the experimental results can be helpful to the development of sludge oil disposing systems for the vessel.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.451-456
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• 2002

This paper describes the properties of Temperature-Viscosity characteristics of hydrous and anhydrous ER fluids containing starch and titanium particle in silicone oil. ER effects arise from electrostatic forces between the starch particles and titanium particles dispersed in the electrically insulating silicone oil induced when electric field is applied. ER fluids under electric field have been found to provide resonable estimates of ER fluid viscosity variation characteristics. Yield shear stress of the ER fluids were measured on the couette cell type rheometer as a function of electric fields. The outer cup is connected to positive electrode(+) and bob becomes ground(-). The electric field is applied by high voltage DC power supply. In this experiment shear rates were increased from 0 to 200/equation omitted/ in 2 minutes.

• 대한환경공학회지
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• 제37권8호
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• pp.458-464
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• 2015

본 연구에서는 사산화삼철과 활성탄을 발열체로 하여 벙커C유 오염토양에 마이크로파를 조사한 후 온도변화 양상 및 TPH 제거효율을 살펴보았다. 사산화삼철 및 활성탄 함유 오염토양에 100~500 Watt로 마이크로파를 조사하였을 때 승온율은 $1.4{\sim}1.6^{\circ}C/Watt$로 나타났다. 조사시간에 따른 온도의 변화는 활성탄보다 사산화삼철 함유토양에서 민감하게 나타났으며, 사산화삼철과 활성탄의 경우 발열체 함량이 각각 10% 이상과 25%에서 열탈착을 위한 충분한 온도가 확보될 수 있음을 관찰하였다. 사산화삼철은 평균 44.1%, 활성탄은 평균 89.4%의 TPH 제거 효율을 나타났으며, 벙커C유의 제거 양상은 활성탄이 함유되었을 때 사산화삼철 보다 고분자탄화수소의 휘발이 더욱 원활하게 진행되고 있음을 확인하였다.

• 한국자원식물학회지
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• 제25권6호
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• pp.700-706
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• 2012

Influences of different seeding dates on growth, seed yield, fatty acid composition and oil content were investigated in flax plants for two years. The results indicated that plant height in early seeding date was higher than that of delayed seeding dates during first season. Furthermore, seeding date also significantly affected the ripened seed rate and the rate increased with the delay in seeding date in first season. Seed yield in the first crop season was significantly higher than the second crop season. Palmitic acid showed variation in different seeding dates. Contrarily, stearic acid was stable and did not changed by different seeding dates. Linolenic acid was found in highest amount in all seeding dates consecutively in two cropping years. Highest oil content was recovered from the seeds of flax sown at 29 Apr. and May 9 in first and second cropping year respectively.

• Journal of Nutrition and Health
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• 제5권2호
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• pp.69-74
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• 1972

The study was made for storage test of Yackwa, which is typical cookies of Korea and contain about 20% of vegetable oil. As the result of investigation the variation of POV and AV of oil contained in Yackwa which was stored in packed or unpacked state for 60 days, at the temperature of $5^{circ}C$ or $30^{circ}C$ respectively, it was found that the Yackwa of AV, about 2, and POV, about 20, was considerably stable for storage. This result of the good storage condition of Yackwa containing a considerable amounts of Vagetable oil which proceed the rancidity, is derived from the formed film on the surface of Yackwa by the sugar syrup afterwards.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2129-2134
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• 2004

The present study has been conducted to develop a heat pump system using river water of temperature energy which not only belongs to unutilized energy but is a kind of good heat source due to maintain its temperature in a certain degree regardless of seasonal variation. The system did not meet the proposed performance after setup. In this paper, the system performance affected by refrigerant Oil, by pressure drop, or by other factors has been discussed. The followings were obtained : (1) Refrigerant Oil mixture rate was 2.5 in weight percentage, (2) Pressure drop through evaporator was 29.1kPa($3.1^{\circ}C$ in saturated tempearture) (3) Pressure drop from the end of evaporator to compressor inlet was 39.8kPa($4.0^{\circ}C$ in saturated tempearture). (4) The system performance can to be improved by modifying a part of pipe line to compressor, and reducing pressure drop through heat exchangers.

• 설비공학논문집
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• 제20권6호
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• pp.388-393
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• 2008

This study has been conducted to select the suitable refrigeration oil for a $CO_2$ refrigeration system. Non-hygroscopic property of refrigeration oils is one of the most important properties for refrigeration oils. PAG and POE oils are considered as test oils in this study. Transient variation of water content of PAG and POE oils was measured for 3 different vessels in the environmental conditions, such as in the range of temperature $25^{\circ}C$ to $40^{\circ}C$ and relative humidity 40% to 85%. The results obtained that water content of both POE and PAG is increased with an increase in the contact area with ambient for 3 different vessels. It is also found that water content of both POE and PAG is increased as the ambient temperature and relative humidity is increased. Non-hygroscopic property of POE oil is found to be much superior than that of PAG oil.

• Tribology and Lubricants
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• 제22권4호
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• pp.218-224
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• 2006

The sludge oils were produced necessarily in the ships operation, so that it will be the best way to manage the sludge oils inside ship itself from a viewpoint of the prevention of marine oil pollution. The ultra-sonic breaking system which recycle the sludge oil from ship into usable oil to be brunt is recognized as a most possible recycling device. In this regards, the purpose of this study is to examine erosion damage,on the SS400 specimen by cavitation and the effect of impact pressure generated from the demolition of the cavity of ultrasonic vibration in the marine sludge oil environment.. The erosion damage of specimen was investigated mainly on weight loss, weight loss rate and maximum erosion rate with variation of the oil temperature as well as the change of space between transducer hem and specimen. The experimental results showed that as the space between ultrasonic vibrator horn and specimen disk increased, the weight loss and weight loss rate decreased and the values were larger in SFO than in SLO. The experimental results can be useful to the development of sludge oil disposing systems and to consider a countermeasure for the prevention of erosion damages by cavitation.

• 설비공학논문집
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• 제20권5호
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• pp.357-363
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• 2008

In order to investigate $CO_2$ heat transfer coefficient and pressure drop by PAG oil concentration during $CO_2$ evaporation, the experiment on evaporation heat transfer characteristics in a horizontal micro-fin tube was performed. The experimental apparatus consisted of a test section, a DC power supply, a heater, a chiller, a mass flow meter, a pump and a measurement system. Experiment was conducted for various mass fluxes($400{\sim}1200\;kg/m^2s$), heat fluxes($10{\sim}30\;kW/m^2$) and saturation temperatures ($-5{\sim}5^{\circ}C$), and PAG oil concentration($0{\sim}5\;wt%$). The variation of the heat transfer coefficient was different in accordance with the oil concentration. With the increase of the oil concentration, the evaporation heat transfer coefficient decreased and the delay of dryout by oil addition was found. Pressure drop increased with the increase of the oil concentration and heat flux, and the decrease of saturation temperature.

• 조명전기설비학회논문지
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• 제14권3호
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• pp.97-106
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• 2000

본 논문에서눈 주상 변압기의 유전정접 측정과 FFT의 이용으로 활선 상태에서 진단할 수 있논 열화 진단 창치를 제안하였다. 본 논문에서 제안한 주상 변압기 열화 진단 장치는 활선 상태에서 절연유위 온도와 유전정점을 측정하며, 진단 결를블 FFT로 처리한다. 진단용 센서에 인가하는 시험 전압은 주상 변압기 2차촉 전압의 0]용으로 외부회 추가 장치 없이도 전단이 가능하다. 또한, 무선 데이터 통선을 이용하여 진단 정보를 지상에서 수신함 으로 주상 변압기의 감사를 별도의 추가 설비 없이 손쉽게 가능하도록 하였다. 시험 전압 가변 실험과 온도 가변 실험을 통하여 제안한 주상 변압기 열화 진단 장치의 유용성을 입증하였다.