• Tribology and Lubricants
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• 제33권2호
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• pp.45-51
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• 2017

Engine oil is a substance used for the lubrication of internal combustion systems. However, in some case, defects in engine systems may contaminate engine oil with fuel. Contaminated engine oil can cause problems in the normal functioning of a vehicle. In this study, we investigate the functional properties of engine oil contaminated with diesel fuel. The test results indicate that the engine oil contaminated with diesel fuel has low flash point, pour point, density, kinematic viscosity and cold cranking simulator value. The contaminated engine oil which has low plash point can cause fire and explosion accident. Furthermore, a four ball test indicates that the contaminated engine oil increases wear scar to poor lubricity. Moreover, we investigate the GC pattern using SIMDIST (simulated distillation) for determination of diesel in engine oil. The SIMDIST analytic result, diesel was detected at earlier retention time than engine oil in chromatogram. Thus the SIMDIST method can define whether engine oil is contaminated by diesel fuel or not. We can use the SIMDIST method for the diagnosis of oil condition instead of analyzing other physical properties that require many analytic instruments, large volume of oil sample and long analysis time.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권1호
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• pp.81-86
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• 2003

기름의 침투거동에 관한 정보는 처리대책의 수립 및 생물학적 영향을 최소화 하기 위한 중요한 단서가 된다. 본 연구에서는 사질지형의 조간대 모형을 이용하여 유출된 기름의 토양침투 거동을 파악하고 침투에 미치는 주된 영향인자를 규명하는 것을 목적으로 하여 연구를 수행하였다. 해수와 유출된 원유의 연안 해변 토양 침투거동은 전혀 달랐다. 해수는 파도와 조석의 물리적 작용에 의해서 토양 중으로 침투를 하였으나, 유출된 원유는 파도에 의해서는 침투되지 않고 조석작용에 의해서만 토양 중으로 침투하는 것을 알 수 있었다. 그리고 평방미터당 1 L의 유출유가 표착하였을 경우 약 70%이상의 유분이 토양 표층 2 cm의 부분에 집중되는 침투경향을 나타내었다. 그리고, 유출된 기름의 토양침투에는 온도의 변화에 의존하는 기름의 점도가 강한 영향을 미치는 것을 알 수 있었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.271-273
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• 2012

This paper is to investigate the effect of waste cooking oil(WCO) on carbonation resistance of high volume fly ash and blast furnace slag concrete. WCO and paint were applied for carbonation resistance materials. As expected, the application of WCO to the concrete help it reduce carbonation depth remarkably, regardless of mixture types. This may be due to the fact that WCO makes the capillary pore block by activating saponification. It is found that the degree of carbonation reduce due to WCO is much higher than the case by Paint.

• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.966-970
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• 2005

To measure the thickness of liquid films from 10 to 60 ${\mu}m$, we used photochromic dye activation. And we used silicone oil with 10 centi-Stokes and commercial photochromic dyes. To make films with exact and known thicknesses, we used two glass wafers. A film formed between two wafers after placing a drop of liquid of known volume on one wafer and covering the other. The film thickness could be estimated from the diameter of wafer and the dropped liquid volume. To quantitatively evaluate the result, captured the images using digital camera then analyzed the images using the image tool. The gray scale intensity using the captured images of activated dye with these thicknesses showed the repeatability below ${\pm}$ 1.0% when measured with a silicone oil solution containing 0.1% SO and SO-ANTH dyes. And we showed that photochromic dye activation method could be used to measure our liquid film thickness ranges.

• Current Applied Physics
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• 제18권11호
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• pp.1218-1224
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• 2018

Pressure-dependent structural and morphological changes of two amphibole minerals, tremolite and actinolite, were investigated up to 7.0 GPa using synchrotron X-ray powder diffraction underthree different pressure transmission media (PTM): water (W), $CO_2$ and silicone oil (SI). The elastic response of tremolite and actinolite are found to be dependent on the PTM used. When using water (W) as PTM, tremolite and actinolite show normal volume contractions with bulk moduli of 74(1) and 78(1) GPa, respectively. When using $CO_2$ as PTM, we observe the formation of calcite from tremolite above 3.8(1) GPa, whereas actinolite did not show any carbonation reaction. Under silicone oil PTM, we observe modulated volume contraction behaviors in both samples, compared to water and $CO_2$ PTM, with bulk moduli in the order of 90(1) and 94(4) GPa for tremolite and actinolite, respectively.

• 청정기술
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• 제12권1호
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• pp.45-51
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• 2006

콜로이드 액상 에이프런(CLA)은 무극성 탄화수소나 알콜, 아민등을 용매로 사용하여 만들 수 있다. 본 실험에서 수행한 CLA의 제조 및 안정성 실험은 수용성 계면활성제와 지용성 계면활성제를 이용하였다. 본 연구에서는 CLA를 제조할 때 사용되는 두 가지 계면활성제의 비율과 추출제의 농도에 따른 콜로이드 액상 에이프런의 안정성을 살펴보았다. 두 가지 계면활성제의 비율(PVR: phase volume ratio)이 변화함에 따라 콜로이드 액상 에이프런의 안정성에 영향을 주었다. 추출제의 농도가 증가할수록 CLA의 안정도는 감소하며, PVR의 값이 높아질수록 CLA의 안정도는 감소한다.

• 열처리공학회지
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• 제27권2호
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• pp.65-71
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• 2014

SMF9060 material is a Fe-based powder sintered alloy that is used for several automobile components such as Synchronize Hub, oil pump and transmission. These components are required excellent wear resistance and durability. In this study, we have performed a dry wear test at the ambient air and Ar gas conditions in the room temperature, and a lubricant wear test at the room temperature and engine oil temperature of $100^{\circ}C$. The amount of wear volume and coefficient friction are measured by a Profilometer and a Ball on disk type wear tester. The wear volume in Ar gas condition was a little higher than that in the ambient air condition. However the wear volume in the lubricant wear condition was much lower than in the dry wear condition. XRD analysis of the debris in Ar gas condition showed that the oxide film was not formed.

• 한국분무공학회지
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• 제7권3호
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• pp.38-44
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• 2002

The purpose of this study is to investigate the effect of the volume fraction of water and injection pressure on the spray characteristics of water/oil emulsified fuel injected from the pressure swirl atomizer. The mixture of light oil and water by using impeller mixer was performed. The spray characteristics such as SMD and velocity were measured using PDPA. The injection pressures were 7.5, 100, 200 and $300kgt/cm^2$ and volume fractions of water in emulsified fuel were 0, 10, 20 and 30%, respectively. The measurement sections were at 30, 60 and 90mm from injection nozzle tip. SMD and velocity of emulsified fuel were larger gradually by increasing the volume fraction of water in emulsified fuel. The spray angle was decreased and axial velocity was increased with increase in water content. It was found that the relative SMD ratio was increased more greatly than the relative axial velocity ratio in super critical pressure. The relative SMD ratio was increased and the relative axial velocity ratio was decreased with increase injection pressure at spray downstream.

• 한국항공운항학회지
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• 제29권2호
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• pp.106-110
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• 2021

In this study, the main factors affecting the number of passengers and cargo volume transported by air between Korea, China and Japan over the past 20 years are to be identified. For the analysis, data from three countries' GDP and per capita as well as exchange rates and international oil prices were used, and OLS multiple regression analysis and fixed effect analysis were performed. As a result of the analysis, both the number of passengers and cargo volume transported by air showed a negative (-) direction for GDP, which represents the country's economic power, and a positive (+) direction, for per capita GDP, which represents income level. And the increase in the exchange rate between China and Japan acted in a positive (+) direction on the increase in the number of passengers, and the effect of oil prices was found to be limited.

• 무역학회지
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• 제42권2호
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• pp.277-296
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• 2017

전 세계 수출입 물동량 중 95% 이상이 해상 수송되고 있다. 이처럼 세계 무역에서 해상 수송이 차지하는 비중이 매우 높다는 점에 주목하여, 본 연구는 해상 물동량과 세계 경제(세계 GDP) 간의 회귀분석을 수행함으로써 상관관계를 추정하였다. 즉, 패널 데이터 분석과 확률효과 모형 분석을 통해 품목별 해상 물동량이 세계 경제 성장에 어떤 영향을 미치는지 실증 분석하였다. 분석 과정에서 해상 물동량을 10개 품목별로 분류하고, 해당 품목의 무역량 변화에 따라 세계 GDP가 얼마만큼 영향을 받는지 추정하였다. 이와 더불어 그랜저 인과성 검정을 수행하여 해상 물동량과 세계 GDP 변수 간의 선후 관계를 검증하고, LR(Likelihood ratio) 검정을 실시하여 확률효과 모형을 통해 회귀분석 하였다. 본 연구의 분석 결과는 정부의 무역 관련 정책을 수립하는 데 많은 도움을 줄 것으로 기대된다.