• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.73-81
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• 1999

Shake mixing has been widely used in cell culture. The mixing performance for shake mixing, however, has not been reported quantitatively. The critical circulating frequency and the power consumption for complete suspension of particles, based on the definition of Zwietering, were measured in a shaking vessel containing a solid-liquid system. The critical suspension frequency was correlated by the equation from Baldi's particle suspension model modified with the physical properties of the particles. Critical suspension frequency was correlated as following ; $$N_{JS}={\frac{0.58\;d{_p}^{0.06}(g{\Delta}{\rho}/{\rho}_L)^{0.004}X^{0.03}}{D^{0.35}d^{0.17}{\upsilon}^{0.04}}}$$ The power consumption at the critical suspension condition in the shaking vessel was less than that in an agitated vessel with impeller.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1690-1698
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• 2006

In order to investigate the effect of dissolved oxygen (DO) level on AVM $B_{1a}$ production by a high yielding mutant of Streptomyces avermitilis, five sets of bioreactor cultures were performed under variously controlled DO levels. Using an online computer control system, the agitation speed and aeration rate were automatically controlled in an adaptive manner, responding timely to the oxygen requirement of the producer microorganism. In the two cultures of DO limitation, the onset of AVM $B_{1a}$ biosynthesis was observed to casually coincide with the fermentation time when oxygen-limited conditions were overcome by the producing microorganism. In contrast, this phenomenon did not occur in the parallel fermentations with DO levels controlled at around 30% and 40% throughout the entire fermentation period, showing an almost growth-associated mode of AVM $B_{1a}$ production: AVM $B_{1a}$ biosynthesis under the environments of high DO levels started much earlier than the corresponding oxygen-limited cultures, leading to a significant enhancement of AVM $B_{1a}$ production during the exponential stage. Consequently, approximately 6-fold and 9-fold increases in the final AVM $B_{1a}$ production were obtained in 30% and 40% DO-controlled fermentations, respectively, especially when compared with the culture of severe DO limitation (the culture with 0% DO level during the exponential phase). The production yield ($Y_{p/x}$), volumetric production rate (Qp), and specific production rate (${\bar{q}}_p$) of the 40% DO-controlled culture were observed to be 14%, 15%, and 15% higher, respectively, than those of the parallel cultures that were performed under an excessive agitation speed (350 rpm) and aeration rate (1 vvm) to maintain sufficiently high DO levels throughout the entire fermentation period. These results suggest that high shear damage of the high-yielding strain due to an excessive agitation speed is the primary reason for the reduction of the AVM $B_{1a}$ biosynthetic capability of the producer. As for the cell growth, exponential growth patterns during the initial 3 days were observed in the fermentations of sufficient DO levels, whereas almost linear patterns of cell growth were observed in the other two cultures of DO limitation during the identical period, resulting in apparently lower amounts of DCW. These results led us to conclude that maintenance of optimum DO levels, but not too high to cause potential shear damage on the producer, was crucial not only for the cell growth, but also for the enhanced production of AVM $B_{1a}$ by the filamentous mycelial cells of Streptomyces avermitilis.

• Journal of Environmental Science International
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• v.25 no.9
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• pp.1233-1239
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• 2016

This study aimed to evaluate changes in the TN and TP removal efficiencies, depending on whether or not a settling process is applied, in a sequencing batch reactor (SBR) process with a membrane bioreactor (MBR). Nutrient removal was considered in terms of developing an advanced water treatment system for ships in accordance with water quality standards set forth by 227(64). For these purposes, the TN and TP concentrations in the inflow and outflow water were measured to calculate the TN and TP removal efficiencies, depending on whether or not a settling process was used. Water discharged from a bathroom, which was constructed for the experiment, was used as the raw water. The experiment that included a settling process was conducted twice, and the operating conditions were: aeration for 90 min, settling for 30 min, agitation for 15 min, and settling for 15 min for one experiment; and aeration for 150 min, settling for 45 min, agitation for 15 min, and settling for 15 min in the other. Operating conditions for the experiment that did not include a settling process were: aeration for 180 min and agitation for 60 min. The concentration of the mixed liquor suspended solids (MLSS) in the reactor was 3,500 mg/L, while the aeration rate was 121 L/min and the water production rate was 1.5 L/min. For the two experiments where a settling process was applied, the average TN removal efficiencies were 44.39% and 41.05%, and the average TP removal efficiencies were 47.85% and 46.04%. For the experiment in which a settling process was not applied, the average TN removal efficiency was 65.51%, and the average TP removal efficiency was 52.51%. Although the final nutrient levels did not satisfy the water quality standards of MEPC 227(64), the TN and TP removal efficiencies were higher when a settling process was not applied.

• KSBB Journal
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• v.24 no.3
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• pp.303-311
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• 2009

A scaling up study for the exopolysaccharide (EPS) production by submerged culture of Ganoderma lucidum was carried out in jar fermenter systems (2.6, 20 and 75 L) under bi-staged pH process. Profiles of dissolved oxygen (DO) and volumetric coefficient of oxygen transfer ($k_La$) as a function of operating variables (agitation speed and aeration rate) was investigated, and a correlation between $k_La$ and operating variables was analysed statistically. Under bi-staged pH process, no limitation of DO was observed at agitation speeds tested in the range of 200 and 600 rpm, and the highest EPS production was obtained at the level of DO of $40{\sim}80%$. From the regression analysis, the relation between $k_La$, gas velocity (Vs), stirrer speed (N) and impeller diameter (Di) could be expressed as : $$k_La=0.555{\times}Vs^{0.42}{\times}(N^3{\times}Di^2)^{0.33}\;(R^2=0.925,\;p<0.05)$$ It was found that under 2.6 L jar fermenter, the optimum agitation speed and aeration rate was 400 rpm and 1 vvm, respectively, obtaining the EPS production of 15.43 g/L. Under the submerged cultivation of G. lucidum in jar fermenters of $2.6{\sim}75\;L$, the similar EPS yields at each fermenter were achieved during scaling up based on $k_La$, and $k_La$ value for maximum EPS production was $85.4{\pm}26.70\;h^{-1}$.

• Resources Recycling
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• v.14 no.6 s.68
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• pp.10-15
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• 2005

In this study, the separation of samarium to neodymium with Karr column was investigated. Separation properties of Sm/Nd binary system was estimated with experimental parameters such as flow rate, initial pH of aqueous phase, saponification of PC88A in organic phase and agitation speed. The extraction rate and distribution coefficient increased with increasing initial pH of aqueous phase at 16.5 ml/min(retention time 10 minute) of flow rate of organic and aqueous phase, and equilibrium pH of aqueous phase after extraction was maintained at 1.5 by saponified PC88A. Also, the extraction rate and distribution coefficient were drastically increased with increasing saponification degree of PC88A and agitation speed, and optimal saponification degree was $40\%$. Extraction rate of Nd and Sm was $19.6\%$ and $72.5\%$ respectively at retention time 10 minute, initial pH 1, saponification degree $40\%$ and agitation speed 120 rpm.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.60-71
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• 1994

The average volume of waste per a person in Korea is exceedingly higher than that of Europeans. But the social movement for the resources recycling and the environmental conservation makes the people play their part in several activities like the Separate Collection System. At the time of this agitation, Korean central government brought the Volume Based Waste Charge System into operation in some regions on a trial basis having full-scale operation nationwidely near at hand. Andong City which is one of points under trial operation had remarkble result during this term in resources recycling as well as wastes reducing. The wastes' diminution reached to 32.0 % and the resources recycling was increased by 13.7 times. The responses from the 701 housewives in Andong were also very stimulative. The neccesity of this system was judged conclusively by 91.6 % of total answerers. Also this system was considered as a successful one by 78.4 % popular support. But not little portion (53.8 %) of the answerers felt that the detail methods of this system were unconvenient. In order to take root this system in it's early stages, the Separate Collection should be carried out perfectly and systematically with top priority. And the next program should be the improvement of the detail methods in this system.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.168-175
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• 2007

Ash melting chamber is one of the key facility of the pyrolysis-melting incineration system, and it should be designed and operated very carefully for avoiding solidification of slag. In this study, an example of numerical and experimental scale-up process of the melting chamber, in which high speed air is injected to the molten slag and generates bubbles, which enhances agitation of the slag and char combustion, is presented. Cold flow test, combustion and melting test in a lab-scale (30 kg/hr) chamber and a pilot scale (200 kg/hr) chamber. Minimum energy for maintaining molten slag is derived, and it was found that the molten slag can be maintained efficiently by concentrating heat into the bubbling slag.

• YAKHAK HOEJI
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• v.22 no.1
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• pp.22-26
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• 1978

The purposes of this investigation were to study the characteristic properties of bismuthoxynitrate formed by hydrolysis of bismuthnitrate according to various reaction conditions and to propose the property difference between synthesized pearl pigment and bismuthsubnitrate as pharmaceuticals by means of X-ray diffraction, IR, DTA and TGA. The pearl pigment could be obtained by reaction of bismuth nitrate-diluted nitric acid solution with cold water (5.deg.) agitation at lower pH. The pearl pigment was BiO. NO$_{3}$. 2H$_{2}$O. in composition and crystalline form was thin plate of monoclinic system and its combination with water was assumed to be hydrated hydrous form between Bi-H$_{2}$O bond. On the other hand, bismuthsubnitrate was 5BiO.4NO$_{3}$.6H$_{2}$O in composition and crystalline form was pillar of rhombic system and the bond between Bi and H$_{2}$O molecules was assumed to be hydrous form. The different properties between two compounds in structure are presumed to be caused by the hydrolysing conditions of bismuthnitrate respectively.

• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.102-107
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• 2001

This research was carried out investigate the removed T-P, T-N and anion surfactants using Autoclaved Lightweight Concrete(ALC) in wastewater treatment system. Effects of pH, TDS on aqueous solution was measured. Specific area which measured by BET was $27.66m^2/g$. The phosphorous, nitrogen and anion surfactants removal efficiencies were examined by using artificial waste water(T-P : 66~73mg/L, T-N : 56~136mg/L and anion surfactants : 10~31mg/L). The results showed that the ALC was effective material as a adsorbent due to the structure and porosity. It was found that anion surfactants removed was 85~95%, phosphate removed was 92% and nitrogen removed was 90% in artificial wastewater. Agitation process was more effective than aeration process in that case of nitrogen removal system using ALC.

• Childhood Kidney Diseases
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• v.1 no.2
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• pp.179-182
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• 1997

Cyclosporine is an immunosuppressant usually used to prevent renal transplantation rejection. Nephrotoxicity and hypertension are considered as the most frequent side effects of cyclosporine treatment. The neurotoxic effects of cyclosporine such as agitation, anxiety, delirium, depression and psychosis have recently been found. Methylprednisolone may increase as well plasma concentration of cyclosporine, which leads to side effects. Here we report a $Henoch-Sch\"{o}nlein$ nephritis patient treated with cyclosporine and methylprednisolone who has experienced psychosis including visual and auditory hallucination and convulsion.