• 보존과학회지
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• 제31권4호
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• pp.361-372
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• 2015

항균 방충제가 은(Ag), 구리(Cu), 납(Pb), 철(Fe) 등의 재질로 구성된 문화재에 미치는 영향을 알아보고자 Oddy test를 실시하였다. 금속시편으로는 은(99.9%), 구리(99.9%), 납(99.9%), 철(99.5%)을 사용하였다. 항균 방충제를 60ml 제조 시 주요성분인 B77 Essential oil mixture에 대하여 표준물질 농도인 17.5%를 기준으로 ${\pm}1{\sim}2%$의 농도로 제조하였으며, 저농도의 B77 Essential oil mixture에 항균성분인 BS-2와 BS-3를 각각 첨가하여 제조하였을 때 금속시편에 미치는 영향도 조사하였다. Oddy test 실험 후의 표면관찰, 중량측정, 색도측정 및 SEM-EDS분석으로 표면의 변화를 알아보았다. 실험 결과 납(Pb)시편이 가장 큰 표면변화를 보였으며, 색측계 측정결과 구리(Cu)의 색차가 가장 컸다. 또한 이 실험을 통해서 B77 Essential oil mixture의 농도 19%에서 실험 전과 후의 시편에서 변화가 가장 컸으며, B78 Essential oil mixture가 포함된 약품에서 비교적 큰 변화가 나타났다. 즉, B77 Essential oil mixture의 농도가 높을 경우에는 표면 변화가 컸으며, B77 Essential oil mixture가 저농도일 경우 B78 Essential oil mixture가 포함되어 제작된 약품에서 비교적 큰 변화를 확인할 수 있었다. 그러나 B78 Essential oil mixture를 첨가하지 않은 저농도의 B77 Essential oil mixture에서는 표면변화가 크지 않음을 확인할 수 있었다.

• International Journal of Air-Conditioning and Refrigeration
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• 제17권3호
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• pp.88-93
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• 2009

Lubricant oil is needed in air conditioning and refrigeration system because the compressor requires oil to prevent surface to surface contact between its moving parts, to remove heat, to provide sealing, to keep out contaminants, to prevent corrosion, and to dispose of debris created by wear. Thus, the oil separation in an oil separator is one of the most important characteristics for proper compressor operation. In this study, a gravity type of oil separator is used. Oil separation characteristics have been investigated for $CO_2$/PAG mixture in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $0^{\circ}C$ to $15^{\circ}C$ at 50 bar and $70^{\circ}C$ to $90^{\circ}C$ at 80 bar. The results obtained indicate that the oil separation is increased with an increase in the oil concentration. It is also found that the oil separation in liquid state is increased with an increase in the mixture temperature while the oil separation in gas state is decreased.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2934-2939
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• 2008

We conducted a test of a direct burning of crude Jatropha oil (CJO) in a commercial boiler system. The fuel, crude Jatropha oil is not biodiesel which comes from transeterification process of bio oil, but it is pure plant oil. The higher heating value (HHV) of the CJO is 39.3 MJ/kg (9,380 kcal/kg) and is higher than that of a commercial heating oil, 37.9 MJ/kg. The kinematic viscosity of CJO is 36.2 mm2/s at $40^{\circ}C$ and 8.0 mm2/s at $100^{\circ}C$. The burner used in the test is a commercial burner for a commercial heatingoil and its capacity is 140 kW (120,000 kcal/h). We did a preliminary test whether the combustion is stable or not. The preliminary test was a kind of open air combustion test using the commercial burner with crude Jatropha oil. We found that the combustion can be stable if the crude Jatrophaoil temperature is higher than $90^{\circ}C$. We measured the flue gas concentration by using a gas analyzer. The NOx concentration is $80{\sim}100\;ppm$ and CO concentration is nearly 0 ppm at flue gas O2 concentration of 3.0 and 4.5%.

• 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.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1990년도 제12회 학술강연회초록집
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• pp.58-62
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• 1990

The size and concentration of wear debris in lubricating oil often reveal the operating condition of the rotating machinery. To evaluate the possible application of light attenuation measurement for the estimation of wear debris concentration in the lubricating oil, the light transmittance through the lubricating oil cell contaminated with various concentrations of diatomite particles was measured, the attenuation coefficient was estimated from the transmittance measurement and the coefficients were compared with those obtained from the scattering theory. The comparision showed good agreements between them. It is also noted that the experimentally determined attenuation coefficient showed almost linear relation with particle weight concentrations for the concentrations within the range of 2000 ppm. For the case of 0 ppm weight concentration of diatomite particles in the lubricating oil cell, the thickness of the cell required to give $100 \mu W$ light attenuation is 7.75 mm. This result indicates that the light attenuation method will be one of the possible candidates of machine failure diagnostic sensors for the estimation of wear debris concentration in the lubricating oil.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.131-136
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• 2008

The oil separation in an oil separator is one of the most important characteristics for proper compressor operation. In this study, a gravity type of oil separator is used. Oil separation characteristics has been investigated for $CO_2$/PAG mixture in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $5^{\circ}C$ to $15^{\circ}C$ and $70^{\circ}C$ to $90^{\circ}C$. The results obtained indicate that the oil separation is increased with an increase in the oil concentration. It is also found that the oil separation in liquid state is increased with an increase in the mixture temperature while the oil separation in gas state is decreased.

• Korean Chemical Engineering Research
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• 제56권2호
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• pp.240-244
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• 2018

There is growing concern about cross infection among the patients to patients, patients to staffs, and tools to patients in healthcare facilities, especially in dentistry. In this study, the most widely used dental impression materials were prepared and the synergy effect of Chlorhexidine and essential oil on antimicrobial activity was examined in the impression materials. Chlorhexidine concentration of 0.1 wt% and 0.5 wt% showed no antimicrobial activity on Escherichia coli (E. coli) and Candida albicans. At 1.0 wt% Chlorhexidine, 0% of E. coli and 34.7% of Candida albicans were survived. Bergamot (Essential oil) concentration of 0.5 wt% and 1.0 wt% showed no antimicrobial activity on E. coli. At 2.0 wt% Bergamot oil, 71.9% of E. coli were survived. Tea tree oil (Essential oil) of 0.5 wt% showed no antimicrobial activity on E. coli. At 1.0 wt% Tea tree oil, 11.2% of E. coli was survived. At 2.0 wt% Tea tree oil, no E. coli was survived. However, no E. coli was survived at the concentration of 0.8 wt% Bergamot with 0.3 wt% Chlorhexidine. At the concentration of 0.8 wt% Tea Tree oil with 0.3 wt% Chlorhexidine, 1.3% of E. coli were survived. The experimental results showed that the synergy effects between Chlorhexidine and essential oils on antimicrobial activity were prominent.

• 환경위생공학
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• 제23권2호
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• pp.27-33
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• 2008

Using crude soybean oil as the sole carbon source, the lincomycin production from Streptomyces lincolnensis LC 345 was investigated in the air lift bioreactor. When 30 g/L of crude soybean oil was used, the maximum lincomycin concentration reached 0.89 g/L, after 5 days of culture. When CSL concentration was increased from 10 to 30 g/L, Lincomycin concentration was increased from 0.6 to 1.2. On the other hand, when CSL concentration was increased from 40 to 60 g/L, it was decreased from 1.15 to 0.7 g/L. Using these results, fed batch cultures for comparing the use of crude soybean oil and glucose as a conventional carbon source were carried out in a 5 L air lift bioreactor. When crude soybean oil was used as the sole carbon source, the maximum lincomycin concentration was 2.0 g/L, which was about 2.0 fold higher than that of glucose medium after 7 day of culture. The product yield from olive oil was 0.042 g/g consumed carbon source, which was about 3.8 fold higher than that of glucose.

• 설비공학논문집
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• 제14권4호
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• pp.285-292
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• 2002

The vapor pressure and miscibility measurement apparatus was developed and used to obtain data for refrigerant/oil mixture. The vapor pressure and miscibility data for R-404A/32 ISO VG polyol ester (POE) oil mixture and R-404A/46 ISO VG polyol ester oil mixture are obtained over the temperature range from -20 to $60^{\circ}$ with at $10^{\circ}$ intervals and the oil concentration range from 0 to 70 wt%. Using the experimental data, an empirical model was developed to predict the temperature vapor pressure-concentration relations for R-404A/46 ISO VG polyol ester oil mixtures at equilibrium. In the R-404A/32 ISO VG polyol ester oil mixture, the average root-mean-square deviation between measured data and calculated results from the empirical model is 1.24% and in the R-404A/46 ISO VG polyol ester oil mixture, that is 1.37%. Miscibility for R-404A/32 ISO VG polyol ester oil mixture was observed all over the experimental conditions. Immiscibility for R-404A/So1est 46 oil mixture was observed at the low oil concentrations (20~30 wt%) over the high experimental temperature range (50~$60^{\circ}$).

• 한국자원식물학회지
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• 제10권2호
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• pp.151-158
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• 1997

본 연구는 콩계통들의 지방함량이 서로 다른 가상요인에 어떻게 영향을 받는 지를 규명하기 위해 미국 노스캐롤라이나지방의 5개 지역에서 3년에 걸쳐 수행하였다. 각 계통의 지방함량 및 지방수량들이 기상요인에 대한 Linear response가 조사되었고, 또한 최저기상 반응모델을 결정하기 위해 Stepwise Selection Program이 사용되었다. 콩지방함량, 지방수량은 기상 요인인 온도와 강우량에 의해 크게 영향을 받았으며 성숙시기에 온도가 가장 높고, 최고최저 온도범위가 가장 작은 환경에서 지방함량이 가장 낮게 나타났고, 최저온도 변이가 가장 작고 강우량변이가 가장 큰 환경에서 지방수량이 가장 높게 나타났다. 계통들의 대부준으 지방함량이 MxDT, HTD, ADT, ADTRg에 반비례하는 경향을 나타내었으며 이는 성숙시기에 온도가 높아질수록 지방함량이 감소한다는 것을 의미한다. 그러나 NC107은 MxDT, ADT에 비례하는 경향을 보였다. 모든 계통들이 VMnDT, VADTRg, ADRa에 비례하는 경향을 나타내었고 이는 최저온도와 최고최저 온도범위의 변이가 클수록, 평균강우량이 많을수록 지방함량은 증가한다는 것을 의미한다. 11계통이 1개 내지 3개의 기상변수를 가지는 최적기상모델을 형성하였다. 그러나 NC109와 NC105는 모든 기상변수에 유의한 Linear 반응을 나타내지는 않았으나 전자는 2개의 기상변수를 가지는 최적기상모델을 형성하였고 후자는 가지지 않았다. 이는 NC109는 지방 함량이 아마도 기상변수 하나에 의한 영향보다도 2개 변수의 상호작용에 의한 영향이 큰 것으로 추측 할 수 있고, NC105는 지방함량이 기상환경에 상대적으로 더 안정하기 때문인 것으로 생각된다. 위와 같은 사실은 콩지방함량의 기상반응에 대한 품종적 차이가 상당히 크다는 것을 의미한다. 지방수량은 ADTRg와 VADRa에 반비례하는 경향을 나타내었으며 이는 최고최저 온도차이와 평균강수량 변이가 클수록 지방수량은 감소한다는 것을 의미한다.