• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.515-519
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• 2014

The fuel properties of biodiesel produced by changing the mixing ratio of methanol and ethanol in trans-esterification of soybean oil and lard were evaluated in this paper. The solubility of oil and fat in ethanol was higher than that in methanol. Also the more homogeneous biodiesel was produced as increasing the mole ratio of ethanol. The conversion characteristics of lard was the best at the mixing mole ratio of methanol and ethanol was 6 : 6 at the reaction temperature of $60^{\circ}C$. On the other hands, the best biodiesel conversion characteristics for soybean oil was obtained at the mixing mole ratio of 3 : 3. The kinematic viscosities of soybean oil and lard based biodiesel were 4.17~4.35 cSt and 4.69~4.93 cSt, respectively. The oxidation stability and higher heating value increased with increasing the mole ratio of ethanol. The oxidation stability satisfied the criteria of biodiesel quality of 6 hours. And finally, the higher heating value was approximately 40 MJ/kg.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.243-248
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• 2011

The purpose of this study is to develop a sensing system to measure the capacitance of a pre-developed engine oil deterioration detection sensor integrated with an oil filter. To measure the capacitance of engine oil in the sensor, it is used the way measuring the electric charging time in a capacitor by impressing DC volt. This method has merits on cost and signal stability. The measured capacitance is compensated by comparison with the one measured by an impedance analyzer. Also, using the dielectric constant gained by an impedance analyzer, the calculating equation of the dielectric constant of engine oil related with the currently developed sensor is decided. Finally, the degradation degree of engine oil is estimated according to the change rate of dielectric constant between green oil and used oil. The newly developed personal controller is to control a series of the processes.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.61-65
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• 1990

Comparison of induction times among the Rancimat Method, the Oven Test and the Weight Method were investigated, and the oxidation stability of perilla oil was determinated by the Rancimat Method. The induction times determinated by three methods using perilla oil show a good correlation. And the temperature dependence of the induction times of perilla oil was as follows. $t_p=e^{-0.0815T+9.183}$. The antioxidant effect of Tocopherols on the oxidation of perilla oil was not observed, and the antioxidant effect of the organic acids was increased in the order of Ascorbic acid>Ascorbyl stearate>Malic acid>Tartaric acid>Citric acid. The synergistic effect of Ascorbic acid (500 ppm)and Tocopherols was not observed below 200ppm of Tocopherols, but became larger with increasing Tocopherols level over 200ppm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.231-234
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• 2000

To evaluate the effect of frying times on the oxidative stability of soybean oil and shortening, they were reused up to 10 times and measured by thiobarbituric acid(TBA) value, acid value(AV), peroxide value(POV) and sensory evaluation. As the reusing time was increased, TBA value of "battered pork" fried with shortening showed more sharply increased than that with soybean oil, while the value of shortening, itself, showed more decreased than that of soybean oil. In frying fat, AV and POV increased with the increase of reusing times. Compared with soybean oil, shortening had rapidly increased for POV as reusing time was increased. Among the sensory analyses TBA of "battered pork" with soybean oil and shortening exhibited the highest correlation with flavor and texture, respectively. For the "batgtered pork" fried with soybean oil and shortening, reusing shelf-lives predicted were approximately 9 and 8 times, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.3
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• pp.103-114
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• 1990

Many high speed mechanical systems incorporate gearing for speed reduction. This study investigates the stability of mulit-rotor geared systems supported on oil film bearings taking into consideration the coupling between torsional and lateral dynamics. The emphasis of the study is on the analysis of the interaction between the combined torsional and whirl insta- bilities. The feasility of inducing a lateral and the torsional instability to neutralize an anticipated unstable condition is investigated. The possibility of suppressing the instabilities by controlling the parameters of the oil film bearings is also considered.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.905-910
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• 2004

Effects of bamboo smoke distillates (BSD) in oxidative stability of oil during storage were investigated. BSD at 0.1, 0.5, and 1.0% was added to palm oil and lard, and peroxide, acid, and TBA values were measured during storage at $60^{\circ}C$ for 25 days. Induction periods and relative antioxidant effectiveness (RAE) for the oils were also investigated. Antioxidative effect increased with increasing concentration of BSD. Oil with 0.1% BSD had higher antioxidative effect than that with 0.02% BHT and much higher than that with 0.02% ${\alpha}-tocopherol$. Induction periods of lipid oxidation were 34.27 and 25.61 days for palm oil and lard, respectively. In oxidation reaction, palm oil was more stable during storage than lard. When 1.0% BSD was added RAEs of palm oil and lard were 233.92 and 2371.62%, respectively. Palm oil with 1.0% BSD showed higher antioxidative effect than that with 0.02% BHT, and lard showed much higher antioxidative effect than palm oil.

• Journal of the Korean Chemical Society
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• v.19 no.1
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• pp.50-52
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• 1975

The oxidation stability of samples prepared by blending samples reported previously with diesel oil and diesel oil with additives(alkyl benzene and phenolic type of materials), was tested to study the mechanism of thermal oxidation stability of the regenerated lubricating oils. It was found that the improvement of thermal oxidation stability of such oils was caused by the formation of aromatic compounds, especially phenolic type of organic materials.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.81-86
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• 2007

Biodiesel fuel that consists of saturated and unsaturated long-chain fatty acid alkyl esters is an alternative diesel fuel produced from vegetable oils or animal fats. However, air causes autoxidation of biodiesel fuel during storage, which can reduce fuel quality by adversely affecting its properties, such as the kinematic viscosity and acid value. One approach for improving the resistance of fatty derivatives to autoxidation is to mix them with antioxidants. This study investigated the effectiveness of five such antioxidants in mixtures with biodiesel fuels produced by three biodiesel manufacturers : tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PrG) and $\alpha$-tocopherol. Oxidation stability was determined using Rancimat equipment. The results show that TBHQ, BHA, and BHT were the most effective and $\alpha$-tocopherol was the least effective at increasing the oxidation stability of biodiesel. This study recommends that TBHQ and PrG be used for safeguarding biodiesel fuel from the effects of autoxidation during storage.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.339-340
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• 2002

Natural castor oil was chemically reconstructed to extend the carbon chains by means of iso-reaction so as to improve the rheological behavior, by way of increasing the viscosity index and decreasing the pour point. The rheological and tribological characteristics of the reconstructed castor oil were comparatively investigated with those of the natural castor oil and several other vegetable oils and a mineral oil. The friction and wear test results on a four-ball machine indicate that the chemically reconstructed castor oil has considerably improved rheological and tribological properties as compared with the natural castor oil. It shows a greatly increase viscosity index and largely decreased pour point, which makes it applicable to low temperature lubrication. The chemically reconstructed castor oil even shows better tribological behavior than pentaerythritol ester or di-iso-capryl sebacate. However, it is still needed to increase the oxidation stability of the reconstructed castor oil.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.531-536
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• 2019

In this study, the optimization of the manufacturing process for the oil-in-water emulsification of rice bran oil was performed by response surface methodology (RSM) using varying amounts of the emulsifier (0.05-0.25%), varying rotation speeds of the homomixer (4,000-8,000 rpm), and varying water to oil ratios (0.8-1.6%) as independent variables, and the emulsion stability index (ESI) as the dependent variable. The optimization conditions predicted by the RSM model were 0.2%g of the total amount of the rice bran oil emulsion, emulsified at the homomixer rotation speed of 6,700 rpm using a water to oil ratio of 1:3. The ESI of the rice bran oil emulsion prepared under the optimized conditions was 95.7%, which was similar to the predicted value of 94.4% obtained by the RSM model. The transmission stability and the backscattering values were found to agree with each other over time and the turbiscan stability index was less than 0.7, indicating that the aggregation and upper floatation were less while the dispersion stability was maintained.