• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.206-212
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• 2013

This study accessed the adsorption characteristics of the 11 perfluorinated compounds (PFCs) on coal-based granular activated carbon (GAC). The breakthrough appeared first for PFODA and sequentially for PFHDA, PFTeDA, PFTDA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, PFOS, and PFHpA. The maximum adsorption capacity (X/M) for the 11 PFCs with apparent breakthrough points ranged from 2.43 ${\mu}g/g$ (for PFODA) to 64.5 ${\mu}g/g$ (for PFHpA). Carbon usage rate (CUR) for PFODA was 0.291 g/day, 11.2 times higher than that for PFHpA (0.026 g/day). The X/M values for the 11 PFCs were fitted well with a linear regression ($r^2$ = 0.89) by their molecular weight (chain length).

• KSBB Journal
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• v.5 no.2
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• pp.167-173
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• 1990

This study is to investigate for obtaining the operating conditions of continuous vinegar production using fluidized bed reactor by Acetobacter aceti cell immobilized in Ca-alginate gel. The optimum conditions obtaining by batch fermentation using fluidized bed reactor were as follows; The fermentation temperature and aeration rate were 3$0^{\circ}C$ and 1.0VVM and the initial concentration of ethanol and acetic acid in medium were 33g/l and 27g/l respectively. The amount of bead used was 25%(w/v). The overall acetic acid productivities of batch fermentations by free cell and immobilized cell were 0.31g/l-hr and 0.48g/l-hr, respectively, at the final acetic acid concentration of 50g/l. In the continuous vinegar production using fluidized bed reactor by immobilized cell under optimum conditions, it was possible to produce 23g/l acetic acid continuously up to 90 days with maximum acetic acid productivity of 2.76g/l-hr at dilution rate 0.12hr-1.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.179-184
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• 1982

The behavior of continuous flow culture of Lartobacillus bulgricus was investigated by application of Monod's kinetic model. The parameters obtained from Monod's chemostat theory successfully predicted the behavior of the chemostat. Then, it was found that Monod's kinetics were applicable to the growth rate dependence on glucose concentration. Under steady-state condition, the maximum growth rate, saturation constant, and wash out were found to be 0.62/hr, 7.69 g/1, 0.51/hr of continuous culture. And the optimum condition for the highest cell production was 0.41/hr in dilution rate, and at that point the cell production rate was 0.178g/1 hr.

• Journal of Korea Foundry Society
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• v.11 no.1
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• pp.44-53
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• 1991

The proper feeding conditions for thin Al-Alloy (AA336, JIS AC8A) castings in permanent mold were investigated to eliminate microshrinkage porosity. 5mm-thick plates (200mm long, 60mm wide) were cast with increasing padding taper from 0 to 5% under different conditions : (1) constant mold temperature of $350^{\circ}C$, (2) continuous production with uniform mold thickness (10mm), (3) continuous production with a negative taper of 2.5% in mold thickness (thickness decreasing in direction to riser). The test casting were machined off to the midplane and the shrinkage porosity was examined visually. The critical padding taper which can just eliminate the shrinkage porosity was determined for each condition, i.e. : (1) 4.5% at the constant mold temperature, (2) 3.5% for continuous production with the uniform mold thickness (3) 1.5% for continuous production with the taper in mold thickness. A computer simulation by a finite difference analysis program was applied to the test casting. The liquid fraction gradient (LFG) and the temperature gradient divided by the square root of the cooling rate (G /SR) were calculated at the end of solidification and compared with the shrinkage porosity area in the castings. For the case of constant mold temperature, LFG is a better parameter to predict shrinkage porosity than G /SR and its critical value is around 11%/cm. But for the case of continuous production, neither LFG nor G /SR could be a reliable parameter. The experimental results about the critical padding taper are of practical interest for designing permanent molds and castings. The computer simulation results stimulate further research to be directed on the prediction of centerline microshrinkage porosity in continuous production.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1227-1234
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• 2020

In this study, yeast cell immobilization was carried out in a packed bed reactor (PBR) to investigate the effects of the volumetric capacity of carriers as well as the different fermentation modes on fuel ethanol production. An optimal volumetric capacity of 10 g/l was found to obtain a high cell concentration. The productivity of immobilized cell fermentation was 16% higher than that of suspended-cell fermentation in batch and it reached a higher value of 4.28 g/l/h in repeated batches. Additionally, using this method, the ethanol yield (95.88%) was found to be higher than that of other tested methods due to low concentrations of residual sugars and free cells. Continuous ethanol production using four bioreactors showed a higher productivity (9.57 g/l/h) and yield (96.96%) with an ethanol concentration of 104.65 g/l obtained from 219.42 g/l of initial total sugar at a dilution rate of 0.092 h^-1. Furthermore, we reversed the substrate-feed flow directions in the in-series bioreactors to keep the cells at their highest activity and to extend the length of continuous fermentation. Our study demonstrates an effective method of ethanol production with a new immobilized approach, and that by switching the flow directions, traditional continuous fermentation can be greatly improved, which could have practical and broad implications in industrial applications.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.597-606
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• 1992

Effects of dilution rate, inlet glucose and ammonium chloride concentrations on ,he performance of continuous culture of Alcaligenes eutrQPhus for poly-p-hydroxybutyrate (PHB) production were investigated. When inlet substrate concentrations were maintained constant (inlet glucose concentration = 20 g/l, inlet ammonium chloride concentration = 2 g/l), growth rate of residual biomass and PHB production rate showed its maximum at $0.1h^{-1}$ and $0.06h^{-1}$, respectively, and washout at $0.13h^{-1}$. PHB content decreased from 50% to 25% by increasing dilution rate, while specific PHB production rate increased continuously. Cell mass and PHB concentration gave its maximum values at inlet ammonium chloride concentration of 2 g/l and thereafter decreased, which showed the existence of substrate inhibition by ammonium. When inlet glucose concentration was 30 g/l, cell mass reached its maximum value, while PHB concentration increased continuously. The parameters of kinetic model were evaluated by the graphical and parameter estimation methods. The computer simulation results for the effects of dilution rate, inlet glucose and ammonium chloride concentrations fitted the experimental data very well.

• Kyungpook Mathematical Journal
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• v.33 no.2
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• pp.205-209
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• 1993

• Journal of applied mathematics & informatics
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• v.23 no.1_2
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• pp.489-496
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• 2007

Let g be a continuous function on an interval I which is not constant on any subinterval of I, and let ${\mu}$ be a Borel measure on I. In this paper we give a necessary and sufficient conditions guaranteeing, for the strongly measurable function f on I with values in a Banach space X, the existence of a continuous primitive function F on I with respect to g.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.504-509
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• 1989

Fermentation condition of Streptococcus lactis IFO 12007 for nisin production was examined. The optimal glucose concentration was 60g/ι. The pH and temperature optimum were 6.5 and 31$^{\circ}C$, respectively. The maximum nisin activity in batch culture was 2000IU/$m\ell$. The fermentation quotients after 7 hours of fermentation in batch culture were; specific glucose uptake rate:0.59g/g/h , specific nisin productivity: 34924IU/g/h, product yield: 5944IU/g, growth yield:0.24, biomass:4.81g/ι. The specific growth rate was affected by pH and temperature and the activation energy for growth was 1.35kcal/mole. pH control was essential for nisin production. Fed-batch culture using 20g/$\ell$ glucose medium produced 1420IU/$m\ell$ after 14 hours. The continuous culture could be operated at below 0.38h$^{-1}$ for nisin production. The steady state nisin concentration and specific nisin productivity were 740IU/$m\ell$ and 45000IU/g/h. The growth yield and maintenance energy were 0.144 and 207mg glucose/g-cell/h.

• KSBB Journal
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• v.17 no.2
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• pp.182-188
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• 2002

Enterococcus faecalis RKY1 cells were immobilized in an asymmetric hollow fiber bioreactor for application to the continuous production of succinic acid. The media was fed into shell-side of the module using a peristaltic pump, and the products were collected through lumen-side outlet. The number of hollow fibers within the module did not affect the bioreactor efficiency in the transverse operated hollow fiber bioreactor. The steady state at the outlet of hollow fiber bioreactor was reached after 24 hr cultivation at flow rate of 0.25 mL/mim, 12 hr at 0.5 L/min, and 9 hr at 1.0 mL/mm, respectively. The succinate and fumarate concentrations within the hollow fiber bioreactor, however, were as changeful as increasing the flow rate. During continuous operation with the flow rates between 0.5 and 2.0 mL, the productivity of succinate was 8.0-10.9 g/L $.$ hr at 30 g/L fumarate, 4.9-14.9 g/L hr at 50 g/L fumarate, and 7.2-17.1 g/L hr at 80 galL fumarate, respectively.