• 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.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.2
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• pp.200-208
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• 2003

The purpose of this study is to propose scientific data and to develop complex\ulcornermultifunctional fibers by applying microcapsules containing rosewood oil on wool fabric. Polyurea was used as wall material of microcapsules. The parameters for adoptable condition are 20min of agitation time, 5000rpm of agitation speed, 4% of emulsifier concentration according to the observation with SEM and particle analyzer. The melting peak of microcapsules was shown to be 280$^{\circ}C$ The amount of released rosewood from microcapsules at 25$^{\circ}C$ was below 1 % and at 40% was below 3%. Therefore, polyurea microcapsules is capable of preserving rosewood oil for long self-life at normal temperature. Antimicrobial activity to dry cleaning and ironing cycle of wool fabric treated with microcapsules were maintained.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.1
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• pp.15-18
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• 2010

Main component of radiography barrier aprons is lead. To manufacture a lead-free barrier sheath, barium sulfate and organic iodine-based chemicals should be mixed with rubber. Barrier capacity was tested in the medical field. To improve adaptation of rubber with the mixture, raw materials went through milling, agitation, and extruding processes. Three sheaths were manufactured with 30%, 80%, and 120% sulfate barium, respectively. This study found 10% lower barrier capacity of lead-free barrier than the traditional lead-containing rubber sheath. Problems, however, were confronted during the agitation and extruding processes. Mixing with rubber was a technically demanding job. Inconsistent depth, problems with thermal processing and dissipation were encountered as well.

• Korea-Australia Rheology Journal
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• v.16 no.3
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• pp.153-160
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• 2004

Open microcellular foams having small-sized cell and good mechanical properties are desirable for many practical applications. As an effort to reduce the cell size, the microcellular foams combining viscosity improvers into the conventional formulation of styrene and water system were prepared via high internal phase emulsion polymerization. Since the material properties of foam are closely related to the solution properties of emulsion state before polymerization, the flow behavior of emulsions was investigated using a controlled stress rheometer. The yield stress and the storage modulus increased as viscosity improver concentration and agitation speed increased, due to the reduced cell size reflecting both a competition between the continuous phase viscosity and the viscosity ratio and an increase of shear force. Appreciable tendency was found between the rheological data of emulsions and the cell sizes of polymerized foams. Cell size reduction with the concentration of viscosity improver could be explained by the relation between capillary number and viscosity ratio. A correlative study for the cell size reduction with agitation speed was also attempted and the result was in a good accordance with the hydrodynamic theory.

• Journal of Microbiology and Biotechnology
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• v.1 no.3
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• pp.197-201
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• 1991

Glycerolysis of triolein by lipase from Chromobacterium viscosum lipase was studied batchwise in AOT-isooctane reversed micelles. The reaction mixture was extracted with chloroform and the content of triolein, 1, 2-diolein, 1, 3-diolein, 1-monoolein, and free fatty acid in the condensed chloroform solution was determined using high performance liquid chromatography (HPLC). The effect of agitation speed on the initial rate of conversion was examined. As the speed of agitation increased up to 700 rpm, the reaction rate increased. However, above 700 rpm, the rate approached maximum and did not increase that much. The glycerolysis activity and the stability of the enzyme were affected by stirring and addition of histidine or copper. Addition of histidine and copper increased the rates of glycerolysis but they are detrimental to the operational stability in reversed micelles.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.419.2-420
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• 2002

Caco-2 is a cell line derived from the human colon adenocarcinoma and often used as a model for studying intestinal drug absorption. It has been well-known that a strong correlation holds between in vitro permeability across Caco-2 cell monolayers and in vivo bioavailability for various drugs. but the correlation curves varied depending on laboratories. The permeabilities of drugs across Caco-2 cell monolayers have been measured under different agitation conditions. (omitted)

• Journal of the Korean Home Economics Association
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• v.23 no.1
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• pp.19-24
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• 1985

The effect of temperature, washing time, mechanical agitation and concentration on the removal from cotton fabrics of tripalmitin labelled with C\sup 14\ were studied. In order to correlate the detergency with the removal mechanism, solubilization and suspending power of surfactants were observed. RESULTS : 1. The detergency from cotton fabric was increased with elevating temperature and over the temperature of maximum detergency, the rate of soil removal was rather decreased. 2. The effects of washing time and mechanical agitation on the removal of triplamitin were obvious at lower temperature. 3. The removal of tripalmitin was remarkably increased at higher concentration over cmc for all surfactants. The detergency of nonionic surfactant -NPPG- was best, this was resulted from its large solubilization and suspending power.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.350-351
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• 2000

We isolated cellulose-producing bacteria from persimmon vinegar(Korea traditional fermentation food). Some of these strains were selected for cellulose production in agitation culture. On the other hand, it was also found that strains suitable for static culture production were not necessarily suitable for agitation culture. Therefore we estimated the cellulose production of these isolates in static culture. To determine nutritional requirement for the production of bacterial cellulose, several nutrients as carbon source, nitrogen and mineral salt were tested.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.356-359
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• 2000

A two-stage fed-batch fermentation was carried out to increase xylitol productivity by Candida tropicalis. The first stage for cell growth was performed in the pH-stat and continuous fed-batch modes. The higher cell growth and lower ethanol production obtained in the fed-batch mode where the growth medium was fed when pH of culture broth increased over 5.7. And also the effect of oxygen transfer on xylitol production was investigated by changing agitation speed under 0.5 vvm of aeration. The maximum xylitol productivity and yield were obtained at 500 rpm of agitation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.2 s.233
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• pp.239-246
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• 2005

Effects of subcooling on pool boiling heat transfer in vertical annuli with closed bottoms have been investigated experimentally. For the test, a tube of 19.1mm diameter and the water at atmospheric pressure have been used. Three annular gaps of 7.05, 18.15, and 28.20 have been tested in the subcooled water and results of the annuli are compared with the data of a single unrestricted tube. The increase in pool subcooling results in much change in heat transfer coefficients. At highly subcooled regions, heat transfer coefficients for the annuli are much larger than those of a single tube. As the heat flux increases and subcooling decrease, a deterioration of heat transfer coefficients is observed at the annulus of 7.05mm gap. Single-phase natural convection and liquid agitation are the governing mechanisms for the single tube while liquid agitation and bubble coalescence are the major factors at the bottom closed annuli.