• Bulletin of the Korean Chemical Society
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• v.20 no.2
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• pp.223-225
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• 1999

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.51-52
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.747-748
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• 2007

• The Korean Journal of Food And Nutrition
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• v.33 no.4
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• pp.440-446
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• 2020

The purpose of this study was to derive the conditions for manufacturing rice porridge with optimum properties after reheating. The characteristics of rice porridge according to the soaking time, water addition rate, heating temperature, heating time, and cooling conditions were compared using the 'Samkwang' cultivar. In Step I, as the heating temperature increased, the weight change decreased and the viscosity increased, and the temperature known as the main factor of the gelatinization also appeared to affect the viscosity increase. In Step II, the viscosity and the texture properties was not significantly different as the soaking time was reduced, and 10 minutes was suitable because of due to the shortening effect of the total process time. In Step III, the residual heat was lowered by cooling after the rice porridge production, so the viscosity could be greatly reduced. Also, it was confirmed that the water addition rate of 900% and the heating temperature of 15 minutes were optimal manufacturing conditions. The next study will investigate the porridge processability of rice cultivars using these results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.681-687
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• 2015

We investigated the effects of feeding rate on the growth performance of growing and sub-adult olive flounder Paralichthys olivaceus, and the optimum feeding rate at high water temperature (25-31℃). In experiment I, two replicated groups of fish (113 g) were fed a commercial diet (CD) at rates of 0, 0.7, 1.2, 1.7, 2.2, and 2.4% (satiation) body weight (BW) per day for 4 weeks. In experiment II, two replicated groups of fish (313 g) were fed a CD feeding rates of 0, 0.3, 0.5, 0.7, 0.9, and 1.0% (satiation) BW per day for 4 weeks. In experiment I, the weight gain (WG) and specific growth rate (SGR) of fish fed at 0.7 and 0.9% BW per day was significantly higher than that of unfed fish (0%) and fish fed at 0.3, 0.5, and 1.0% (satiation) BW per day. In experiment II, the WG and SGR increased significantly as feeding rate increased from 0 to 2.2% BW per day, but decreased in the satiation group (2.4%). Broken-line regression analysis of WG showed that the optimum feeding rate of growing and sub-adult olive flounder were 1.98% and 0.55% BW per day, respectively, at the high water temperature.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.41-45
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• 2003

A study was under taken to investigate the appropriate explant sources of flower organ and suitable cultural conditions such as light, temperature, and sucrose in plant regeneration of Iris ensata culture. Explants of perianth, ovary, pedicel, and peduncle of Iris ensata were cultured at different daylength (0, 8, 16, 24 hour), different temperatures (10, 15, 25, 3$0^{\circ}C$), and sucrose concentrations (1, 3, 6, 9%) on MS medium. Formation of adventitious roots from explants of Iris ensata was effective in the dark, while that of adventitous shoots was effective in the light. The optimum daylength for young plant regeneration was 16 hours. The optimum temperature for shoot formation of Iris ensata explants was $25^{\circ}C$ but the formation at 10 and 15$^{\circ}C$ was ineffective. Especi-ally, perianth and ovary was effective in shoot formation from flower organ expants. T-he optimum concentration of sucrose for shoots and roots formation of Iris ensata explants was 3 and 6%, respectively.

• Journal of Korea Foundry Society
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• v.13 no.6
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• pp.532-539
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• 1993

The effect of casting variables for making pure Al and Al-5wt%Si alloy rods free from any surface and inside defects was studied by adopting the horizontal continuous casting method with heated mold. The rods were cast under the casting conditions such as the mold temperature of $670{\sim}690^{\circ}C$, water flow rate of $0.2{\sim}0.6{\ell}/min$, and rod diameter of $4{\sim}8mm$, when the melt temperature and mold to cooler distance was fixed at $700^{\circ}C$ and 20mm, respectively. The results represented that the casting speed for good quality rod increased as the water flow rate increased, whereas, the casting speed decreased as the rod diameter or mold temperature increased. The statistical analysis of $2^3$ factorial design was also applied and the results represented that the averaged optimum casting speed for pure Al(302mm/min) was higher than that of Al-5wt%Si alloy(273mm/min) resulting from the difference of superheat applied. The effect of rod diameter on the optimum casting speed was the highest for pure Al as well as Al-5wt%Si alloy. The effect of water flow rate and mold temperature on the optimum casting speed was in decreasing order.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.33-38
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• 2013

In the past, a very popular method for reducing the corrosion on zinc involved the use of chemical conversion layer coatings based on $Cr^{+6}$. However, there is an important problem with using chromium salts as a result of restrictive environmental protection legislation. This study investigated the optimum condition for galvanized steel using an organic/inorganic solution with a Ti composition. In the case of a fixed heat treatment time, the corrosion resistance values of LR-0727(1) and LR-0727(2) were improved as the heat treatment temperature increased, and the optimum minimum temperature decreased with the heat treatment time. At the optimum heat treatment condition of two coating solutions, the heat treatment time of the LR-0727(1) solution was shorter than LR-0727(2) for the same heat treatment temperature. LR-0727(1) coated specimens did not show desquamation, and all of the specimens showed a good adhesive property. In contrast, in the case of the LR-0727(2) coated specimens, desquamation arose. Therefore, the adhesive property of LR-0727(1) was superior to that of LR-0727(2). The pencil hardness had a 3H average for all of the coating solutions and heat treatment conditions. In the case of a corrosion resistance test with boiling water, the coated specimens of LR-0727(1) were discolored, but LR-0727(2) was not. Finally, LR-0727(1) was more moisture proof than LR-0727(2).

• Journal of Ginseng Research
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• v.39 no.4
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• pp.304-313
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• 2015

Background: Ginsenoside Rg3 is a promising anticancer agent. It is usually produced by heat treatment of ginseng, in which ginsenoside Rb1 is the major ginsenoside. A kinetic study was conducted to optimize ginsenoside Rg3 production by the heat treatment of ginsenoside Rb1. Methods: Ginsenoside Rb1 was heated using an isothermal machine at $80^{\circ}C$ and $100^{\circ}C$ and analyzed using HPLC. The kinetic parameters were calculated from the experimental results. The activation energy was estimated and used to simulate the process. The optimized parameters of ginsenoside Rg3 production are suggested based on the simulation. Results: The rate constants were $0.013h^{-1}$ and $0.073h^{-1}$ for the degradation of ginsenosides Rb1 and Rg3 at $80^{\circ}C$, respectively. The corresponding rate constants at $100^{\circ}C$ were $0.045h^{-1}$ and $0.155h^{-1}$. The estimated activation energies of degradation of ginsenosides Rb1 and Rg3 were 69.2 kJ/mol and 40.9 kJ/mol, respectively. The rate constants at different temperatures were evaluated using the estimated activation energies, and the kinetic profiles of ginsenosides Rb1 and Rg3 at each temperature were simulated based on the proposed kinetic model of consecutive reaction. The optimum strategies for producing ginsenoside Rg3 from ginsenoside Rb1 are suggested based on the simulation. With increased temperature, a high concentration of ginsenoside Rg3 is formed rapidly. However, the concentration decreases quickly after the reaching the maximal concentration value. Conclusion: The optimum temperature for producing ginsenoside Rg3 should be the highest temperature technically feasible below $180^{\circ}C$, in consideration of the cooling time. The optimum reaction time for heat treatment is 30 min.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.700-704
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• 2009

A simulation study on SCR(steam carbon dioxide reforming) in gas-to-liquid(natural gas to Fischer-Tropsch synthetic fuel) process was carried out in order to find optimum reaction conditions for SCR experiment. Optimum operating conditions for SCR process were determined by changing reaction variables such as temperature and $CH_4/steam/CO_2$ feed ratio. Simulation was carried out by Aspen Plus. During the simulation, overall process was assumed to proceed under steady-state conditions. It was also assumed that physical properties of reaction medium were governed by RKS(Redlich-Kwong-Soave) equation. Optimum simulation variables such as temperature and feed ratio were determined by considering $H_2/CO$ ratio for FTS(Fischer-Tropsch synthesis), $CH_4$ conversion, and $CO_2$ conversion. Simulation results showed that optimum reaction temperature and $CH_4/steam/CO_2$ feed ratio in SCR process were $850^{\circ}C$ and 1.0/1.6/0.7, respectively. Under optimum temperature of $850^{\circ}C$, $CH_4$ conversion and $CO_2$ conversion were found to be 99% and 49%, respectively.