• Journal of Conservation Science
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• v.31 no.4
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• pp.361-372
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• 2015

The experiment attempts to find out the effect of the mixture of the antimicrobial agent and insecticide on metallic material including Silver(99.9%), Copper(99.9%), Lead(99.9%) and Iron(99.5%) by Oddy test. The mixtures of the antimicrobial agent and insecticide were prepared in 60ml; with the standard concentration of 17.5% in B77 Essential oil mixture, one for mixture of concentration of ${\pm}1{\sim}2%$ and insect repellent material; the other for mixture of low concentration and antimicrobial agent(BS-2 and BS-3) material. After Oddy test, we investigated the variation in the surface of the samples by visual inspection, weighing, color measurement and SEM-EDS analysis. The result showed that Lead had the biggest change in the surface, and Copper had the biggest change in the color. In addition, changes in the samples before and after the experiment were found to be greatest at concentration of 19% of Essential oil mixture of the antimicrobial agent and insecticide. Also, B78 Essential oil mixture produce change in samples. It means when the concentration of oil mixture rises, the variation of the samples gets bigger. And, the low concentration of mixture including B77 Essential oil mixture and B78 Essential oil mixture also produce big change in the samples. However, the low concentration of B77 Essential oil mixture that do not contain B78 Essential oil mixture was able to confirm that the change of the surface is not large.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.3
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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.

• Proceedings of the KSME Conference
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• 2008.11b
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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%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.5
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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.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1990.11a
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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.

• Proceedings of the SAREK Conference
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• 2008.11a
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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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• v.56 no.2
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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.

• Journal of environmental and Sanitary engineering
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• v.23 no.2
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.4
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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~$60^{\circ}$).

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.151-158
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• 1997

This study was carried out to identify how soybean seed oil is influenced by climatic factors and to investigate how genotypes differ in their responses. Twelve lines selected were studied in 13 environments of North Carolina. Responses of oil concentration and total seed oil to climatic variables were investigated using a linear regression model. The best response models were determined. There were wide climatic effects in oil concentration and total seed oil. The lowest oil concentration environment was characterized by the most HTD and the smallest VADTRg and the lowest total oil environment was distinguished by the largest VADTRa and the smallest VMnDT. For oil concentration, most lines except for NC107 responded negatively to MxDT, HTD, ADT, and ADTRg, although they had different degrees of sensitivities, indication that warmer temperature may result in decreased oil concentration. All lines responded positively to VMnDT, VADTRg, and ADRa, although they had different degrees of sensitivities, suggesting that larger variation in minimum daily temperature and average daily temperature range and more average daily rain may result in increased oil concentration. Eleven lines had best response models with 1 to 3 variables. However, although NC109 did not show a significant sensitivity to any variable, it had the best response model with 2 significant variables, demonstrating that an interaction between 2 variables might be more critical in determining oil concentration than one variable.