• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.3
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• pp.512-518
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• 1996

Microcapsules containing 2, 4, 4'-trichloro-2-hydroxydiphenyl ether and perfumes were prepared by the coacervation using poly (vinyl alcohol) and crosslinking agents. Effects of dispersing agents, core materials, agitating speed and crosslinking agents on microcapsule size were investigated. The mean and deviation of microcapsule diameters decreased with increasing agitation speed. The diameters of m;crocapsules decreased with increasing dispering agent concentration at 6, 000 rpm of agitation speed, but it was not changed at 10, 000 rpm. The dispering effect of PVA is better than that of gum arabic. The slight increase in the diameter of microcapsule was observed when the amount of core material was increased. As the amount of crosslinking agent was increased, the diameter of microcapsule was decreased.

• Fisheries and Aquatic Sciences
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• v.11 no.4
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• pp.224-228
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• 2008

With the aim of increasing the $CoQ_{10}$ production in mass culture, the effect of aeration-agitation on the $CoQ_{10}$ production using Rhodobactor sphaeroides was investigated in a l-L bioreactor. The maximum $CoQ_{10}$ production was 1.69 mg/g of dry cell weight under conditions of 50 Lux, $30^{\circ}C$, 300 rpm, and 5-vvm aeration. The $CoQ_{10}$ production was improved to produce 2.91 mg/g of dry cell weight under reduced conditions of agitation speed (200 rpm) and aeration rate (0.2 vvm). When R. sphaeroides was cultivated under more reduced DO levels during the exponential phase of the cell, the $CoQ_{10}$ production yield of 3.88-mg/g dry cell weight was the maximum obtained. Therefore, poorer conditions of aeration-agitation resulted in higher production of $CoQ_{10}$, and thus DO content was a crucial factor in the production of $CoQ_{10}$. Accordingly, it was necessary to control the DO concentration in order to enhance the $CoQ_{10}$ biosynthesis within a large-scale production.

• Applied Chemistry for Engineering
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• v.4 no.3
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• pp.537-543
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• 1993

The effect of agitation on liquid-liquid dispersion was investigated in an immisible liquid phase(n-hexane/water) system. Four different types of six-bladed turbine impellers were used: a flat blade, two screen blades and a solid edged 60 mesh screen blade. We found that the extent of dispersion of organic phase and power consumption of agitator were decreased in the order of flat, solid edged, 60 mesh, and 40 mesh blades at same agitation speed. And the minimum agitation speed for complete dispersion of organic phase was increased with increasing volume fraction of organic phase. Also, mean diameter of liquid droplets of dispersed phase was decreased with increasing agitation speed and it was increased in the order of solid edged, flat, 60 mesh, and 40 mesh screen blades at same agitation speed. At complete dispersion, the minimum power consumption was not vary significantly with impeller blade types, but the solid edged screen blade impeller gave the smallest and uniform sizes of liquid droplets, and it had a good performance for liquid-liquid dispersion. In this condition, Power number was not affected by Reynolds number and it was constant in turbulent flow region, and Sauter mean diameter($d_{32}$) of liquid droplets was expressed as a function of volume fraction of organic phase(${\phi}$) and Weber number($N_{We}$) as follows: $d_{32}/D=a(1+b{\phi})N_{We}{^{-0.6}}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.23-28
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• 1985

The extraction rate of lipids from the chopped whole fish was studied with various solvents. Factors which can influence on the extraction rate such as temperature, moisture content, agitation speed and solvent were also examined. In the early stage of extraction, it is considered that the rapid extraction was attributed to cell destruction which occurs in chopping the whole fish and in the later stage, the extraction rate was increased linearly with extraction time. The effect of agitation on the extraction rate had a great influence on the early stage of extraction. In agitation speed of 100, 200, 300 and 500 r.p.m. the slopes of extraction curve were -0.075, -0.075, -0.069 and -0.064, respectively. Extractability between hydrophilic and hydrophobic solvent showed a great difference. It is suggested that extractability difference between acetone and isopropyl alcohol is due to acetone property which can not extract phospholipids in polar lipids. Extractability of lipids was increased with increasing temperature and decreased with increasing moisture content.

• Resources Recycling
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• v.30 no.2
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• pp.24-30
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• 2021

Dismantling tests were performed to separate components from waste printed circuit boards (PCBs) using HCl solution with Sn4+. Then, the effects of agitation speed, reaction temperature, initial Sn4+ concentration, and HCl concentration on the dismantling of components were investigated. No significant effect on the dismantling speed was observed upon changing the agitation speed from 100 to 300 rpm. However, the dismantling rate increased with increasing reaction temperature, Sn4+ concentration, and HCl concentration. In the all-component dismantling tests, when the dismantling ratio increased to 100%, no solder was observed on the boards, and the Sn4+ concentration was ~1,500 mg/L. The dismantling ratio of the components from the PCB increased to 100% within 2 h when 1 mol/L HCl solution with 10,000 mg/L Sn4+ was used at an agitation speed and temperature of 200 rpm and 90 ℃, respectively.

• Journal of Life Science
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• v.6 no.2
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• pp.129-134
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• 1996

The development of fish feed is essential to aquaculture. Recently, yeast, dhlorella and plankton have been studied and development as the feed of the fry fishes, But, these biological feeds cause the nutritional unbalance to fry fishes, rotifer or artemia. Therefore, to solve these problems, microcapsules with micron sizes were prepared for enhancing the nutritional values of artemia and rotifer which are used as the feed of fry fishes. Microparticle oil capsules were prepared by the complex coacervation technique. The method to make the optimal size of microcapsule which the artemia and rotifer can be easily taken was wvaluated. The size of oil microcapsule in the range of 5-70$\mu$m was obtained by the agitation conditions during coacervation. Capsule size and size distribution were dependent on the agitation speed and agitation time, respectively.

• Applied Chemistry for Engineering
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• v.2 no.3
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• pp.209-215
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• 1991

The effect of agitation on the dispersion of organic phase was investigated in an immiscible liquid system (n-hexane/40 wt % p-TSA aqueous solution). Four different types of six-bladed turbine impellers were used : a flat blade type and three screen blade types. The experimental results showed that the extent of dispersion of organic phase at the same agitation speed was decreased in the order of flat blade, 60 mesh, 40 mesh, and 20 mesh screen blades. Otherwise, it was increased with increasing the concentration of TBA as a surfactant agent and with decreasing volume fraction of organic phase. Also, the minimum agitation speed for a complete dispersion was increased in the order of flat blade, 60 mesh, 40 mesh, and 20 mesh screen blades. However, the minimum power consumption did not vary significantly. In this condition, the relationship between Power number and Reynolds number was expressed as $N_p=a\;N_{Re}{^b}$, where the values of constant a and constant b were ranged 2200~4100 and -0.69~-0.63 respectively.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.1-11
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• 2006

The W/O emulsion was formed by mixing hydrophobic nonion surfactants of span 80 and tween 60 with kerosine, and by adding sodium silicate aqueous solution. Precipitating the W/O emulsion by sodium bicarbonate resulted in spherical silica particles. Shape and size distribution of silica particles were observed. The particles were spherical and they have narrow size distribution. Particle sizes were 9.29, 7.39 and $5.73\;{\mu}m$ at homogenizer speed of 2500, 3000, and 3500 rpm, respectively. The particle size was decreased by increasing agitation speed due to the formation of emulsion droplet. At fixed agitation speed, absorbed paraffin oil weight were measured and the $SiO_2/Na_2O$ mole ratio effects on particle size were investigated. Particle size was decreased by increasing the mole ratio of $SiO_2/Na_2O$.

• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.32-35
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• 1996

Amoving aeration-membrane (MAM) bioreactor was employed for the production of 2$\mu$g/mL of tissue type Plasminogen Activator (tPA)in serum free medium from normal human fibroblast cells. This system could maintain high cell density for long periods of steady state conditions in perfusion cultivation. Under normal operating condition, shear stress was as low as 0.65 dynes/$\textrm{cm}^2$ at the agitation speed of 80 rpm. Even though cell density gradually decreased with increasing agitation speed, tPA production increased linearly with increasing shear stress within a moderate range. This culture system allowed production of 2$\mu$g tPA/mL while maintaining a high cell denisty of 1.0$\times$107 viable cell/mL.

• KSBB Journal
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• v.17 no.3
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• pp.307-310
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• 2002

In order to obtain high density seed cells for biofiltration, we studied batch and fed-batch culture of P. putida. Studies were carried out to find optimum fermentation conditions such as pH, concentration of glucose and agitation speed. Specific growth rate of P. putida was dependent on agitation speed and a high rpm of 300 was necessary to carry out the efficient aerobic growth of P. putida. Specific growth rate was highest at pH 7. Feeding glucose and yeast extract continuously at the initial growth phase was the most effective way to get high cell density of P. putida.