• Food Science and Biotechnology
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• v.17 no.2
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• pp.324-329
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• 2008

The effect of ultra-high pressure homogenization on the emulsifying properties of whey protein was investigated in a model emulsion made with whey protein isolate and soya oil under various pH. The emulsifying properties, the average diameter of the oil droplets ($d_{vs}$), and the protein load, were measured for each emulsion produced at different homogenization pressures (50 to 200 MPa) and pH values (4.6 to 8.0). According to the results of variance analysis and response surface, the pH had more influence on oil droplet size and protein load than homogenization pressure. The model equations, which were obtained by response surface analysis, show that pH and homogenization pressure had the major effect on oil droplet size and protein load. Higher homogenization pressure decreased the average droplet size and the protein load. Homogenization at high pressure, as opposed to low pressure, causes no overprocessing, but the effect was pH-dependent. The average diameter of the oil droplets increased slightly by decreasing the pH from 8.0 to 6.5 and then increased dramatically toward the isoelectric point of whey protein (i.e., at pH 4.6). Moreover associated droplets were found at acidic pH and their size was increased at high temperature.

• Journal of Soil and Groundwater Environment
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• v.21 no.1
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• pp.72-79
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• 2016

Bioremediation is one of the most effective ways to remediate TPH-contaminated sites. However, under actual field conditions that are not at the optimum temperature, degradation of microorganisms is generally reduced, which is why the efficiency of biodegradation is known to be significantly affected by the soil temperature. Therefore, in this study, the labscale experiment was conducted using indigenous crude oil degrading microorganisms isolated from crude oil contaminated site to evaluate the remediation efficiency. Crude oil degrading microorganisms were isolated from crude oil contaminated soil and temperature, which is a significant factor affecting the remediation efficiency of land farming, was adjusted to evaluate the microbial crude oil degrading ability, degradation time, and remediation efficiency. In order to assess the field applicability, the remediation efficiency was evaluated using crude oil contaminated soil (average TPH concentration of 10,000 mg/kg or more) from the OO premises. Followed by the application of microorganisms at 30℃, the bioremediation process reduced its initial TPH concentration of 10,812 mg/kg down to 1,890 mg/kg in 56 days, which was about an 83% remediation efficiency. By analyzing the correlation among the total number of cells, the number of effective cells, and TPH concentration, it was found that the number of effective microorganisms drastically increased during the period from 10 to 20 days while there was a sharp decrease in TPH concentration. Therefore, we confirmed the applicability of land farming with isolated microorganisms consortium to crude oil contaminated site, which is also expected to be applicable to bioremediation of other recalcitrant materials.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.411-418
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• 2019

In this study, to investigate the effect of physical and chemical properties of butanol on the engine performance and combustion characteristics, the coefficient of variations of IMEP (indicated mean effective pressure) and fuel conversion efficiency were obtained by measuring the combustion pressure and the fuel consumption quantity according to the engine load and the mixing ratio of diesel oil and butanol. In addition, the combustion pressure was analyzed to obtain the pressure increasing rate and heat release rate, and then the combustion temperature was calculated using a single zone combustion model. The experimental and analysis results of butanol blending oil were compared with the those of diesel oil under the similar operation conditions to determine the performance of the engine and combustion characteristics. As a result, the combustion stabilities of D.O. and butanol blending oil were good in this experimental range, and the indicated fuel conversion efficiency of butanol blending oil was slightly higher at low load but that of D.O. was higher above medium load. The premixed combustion period of D.O. was almost constant regardless of the load. As the load was lower and the butanol blending ratio was higher, the premixed combustion period of butanol blending oil was longer and the premixed combustion period was almost constant at high load regardless of butanol blending ratio. The average heat release rate was higher with increasing loads; especially as butanol blending ratio was increased at high load, the average heat release rate of butanol blending oil was higher than that of D.O. In addition, the calculated maximum. combustion temperature of butanol blending oil was higher than that of D.O. at all loads.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.4
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• pp.518-527
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• 1999

The solubility and miscibility measurement apparatus has been developed and used to obtain data for refrigerant/oil mixture. The solubility and miscibility data for R-134a/46 ISO VG Polyalkylen Glycol(PAG) oil mixture are obtained over the temperature range from -20 to 6$0^{\circ}C$ with a 1$0^{\circ}C$ interval and the oil concentration range from 0 to 90wt%. Using the experimental data, an empirical model is developed to predict the solubility relations for R-134a/PAG oil mixture at equilibrium. The average root-mean-square deviation between measured data and calculated results from the empirical model is 4.2%. Raoult's rule and Flory-Noggins theory are also used to predict mixture behavior. Immiscibility is observed for R-134a/46 ISO VG PAG oil mixture at low oil concentrations of 4.6, 10.1, and 20.4wt%.

• 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.

• Journal of Mechanical Science and Technology
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• v.15 no.6
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• pp.685-692
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• 2001

This paper reports on the mixed lubrication characteristics between the cam and the tappet contact surface of direct acting type valve train systems. First, the dynamic characteristics are solved by using the lumped mass method to determine the load conditions at the contact point. Then, the minimum oil film thickness is calculated with consideration of elastohydrodynamic line contact theory and the friction force is obtained by using the mixed lubrication model which separates the hydrodynamic and the boundary friction. Finally, the average surface temperatures are calculated by using the flash temperature theory. The results show that, there are some peaks in the friction force due to the asperity contact friction, and flash temperature at the position of minimum oil film thickness. It is thought that there is a relationship between the surface temperature and cam surface wear, and therefore, the analysis on the worn cam profile has been performed.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.278-285
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• 1994

Aging test was done by loading back method for 20kVA amorphous core transformers manufactured by Hyosung Industries Co. and korea Electric Power Corporation. Iron losses, copper losses and insulation oil temperatures of the transfromers was measured for all the testing period. Expected life of amorphous core transformers on the basis of the degradation of the insulators was 46 years at 100% load, and 2.4 years at 130% load. Average temperature rising of transformer oil of amorphous core transformers was higher than that of silicon steel core transformers. Hence lowering the oil temperature by optimized design is needed for improving the expected life of the amorphous transformers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.140-150
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• 1996

CFC-12, which has been used most widely in automobile air conditioners and household refrigerators is scheduled to be phased out soon because of its high ozone depletion potential. Now HFC-134a is suggested as an alternative refrigerant for CFC-12. In this Study, we intended to investigate how PAG oil influence evaporation heat transfer and flow pattern, using R-134a and PAG oil influences evaporation heat transfer and flow pattern, using R-134a and PAG oil in the horizontal miro-fin evaporation tube. Experiments were conducted under the flowing est conditions : mass velocity 86-250kg/$m^2$s, heat flux 5-30 ㎾/$m^2$, oil concentration 0-21 wt.% and saturation temperature 5$^{\circ}C$. Local evaporation heat transfer coefficients were found to be higher at the top, side and bottom of the tube in this order. Average heat transfer coefficients turned out to increase with oil concentration increment up to 3 wt.% oil concentration, whereas heat transfer coefficients gradually decreased over 3 wt.% oil concentration, because of oil-rich liquid film was formed on the heat transfer surface. Flow patterns were rapidly transitioned to annular regimes up to 3 wt.% oil concentration. In case of pure refrigerant, measured heat transfer coefficients in the experiments were similar to those of Kandlikar＇s correlation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.93-98
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• 2005

Total tocopherol and phenol contents were determined for virgin and pure oilve oil, and their autoxidation and thermal oxidation were compared with those of commercial soybean oil, in the presence or absence of fluorescent light. The total tocopherol contents of virgin, pure olive oil, and soybean oil were 15.7, 11.2, and 80.7 mg/100 g, respectively. Their total phenol contents were 10.4, 1.6 and 0.5 mg/l00 g, respectively. In autoxidation under dark place at 45$^{\circ}C$, the oxidative stability of the substrate oils decreased in order of virgin oilve oil, pure olive oil, and soybean oil. The average temperature coefficients of the virgin, pure olive oil and soybean oil in the range of 45∼$65^{\circ}C$ were 1.73, 1.83 and 1.64, and the activation energies were 26.86, 29.49, and 24.07 KJ/mol, respectively. In temperature range of 45∼$65^{\circ}C$, pure olive oil was the most susceptible to temperature change, whereas soybean oil the least. In autoxidation under fluorescent light at 45$^{\circ}C$, the oxidative stability of substrate oils decreased in the order of soybean oil, pure olive oil, and virgin olive oil. In thermal oxidation at 18$0^{\circ}C$, the oxidative stability of substrate oils decreased in order of pure olive oil, virgin olive oil, and soybean oil.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.10
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• pp.559-563
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• 2009

Performance of refrigerant oil at the thrust-bearing and at the journal-bearing of a scroll compressor is a significant factor. This paper presents the friction and anti-wear characteristics of nano oil with a mixture of a refrigerant oil and carbon nano particles. The characteristics of friction and anti-wear using nano-oil is evaluated using the disk on disk tester for measuring friction surface temperature and the coefficient of friction. The average friction coefficient of nano-oil was reduced by 60% compared to raw oil under 600 N and 1,000 rpm. It is believed that the interaction of nano particles between surfaces can be improved the lubrication in the friction surfaces. Worn surfaces of frictional specimen were also investigated by the optical and atomic force microscopy. Conclusively, it is expected that wear and friction coefficient of compressor can be reduced by alignment applying nano-oil as refrigerant oil.