• Nuclear Engineering and Technology
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• v.9 no.1
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• pp.15-31
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• 1977

New conception of batch and period is defined appropriate for the on-power refuelling scheme of a heavy water-moderated reactor, A computer code (“HWRCOST”) is developed using nuclear fuel cycle economic equations based on the continuous energy calculation method. The fuel cycle cost of the CANDU-PHW reactor is calculated and sensitivity analyses are performed with variation of uranium ore price, fabrication cost, spent fuel permanent disposal expenses, and capacity fctor.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.637-642
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• 1987

In immobilized cell reactors, effective cell mass is a very important parameter which must be estimated during operation for control and regeneration of biocatalyst. In this report, the effective cell mass in immobilized cell reactor was studied using a sequential estimation method. An immobilized yeast reactor was operated in batch recycle mode. The states of the immobilized cell reactor could be estimated from the process data using an extended Kalman filter.

• Environmental Engineering Research
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• v.24 no.1
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• pp.107-116
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• 2019

Nitrogen removal, nitrous oxide ($N_2O$) emission and microbial community in sequencing batch and continuous-flow intermittent aeration processes were investigated. Two sequencing batch reactors (SBRs) and two continuous-flow multiple anoxic and aerobic reactors (CMRs) were operated under high dissolved oxygen (DO) (SBR-H and CMR-H) and low DO (SBR-L and CMR-L) concentrations, respectively. Nitrogen removal was enhanced under CMR and low DO conditions (CMR-L). The highest total inorganic nitrogen removal efficiency of 91.5% was achieved. Higher nitrifying and denitrifying activities in SBRs were observed. CMRs possessed higher $N_2O$ emission factors during nitrification in the presence of organics, with the highest $N_2O$ emission factor of 60.7% in CMR-L. SBR and low DO conditions promoted $N_2O$ emission during denitrification. CMR systems had higher microbial diversity. Candidatus Accumulibacter, Nitrosomonadaceae and putative denitrifiers ($N_2O$ reducers and producers) were responsible for $N_2O$ emission.

• Clean Technology
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• v.25 no.2
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• pp.101-106
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• 2019

The aim of this study is to investigate the feasibility of an Ni-SA catalyst, which was prepared from nickel, kieselguhr, and alumina, for the hydrogenation of triglyceride in a bench-scale reactor. Ni-SA powders were prepared by precipitating nickel precursors on a silica and alumina support. The powder was reduced in a hydrogen flow, mixed with a saturated palm oil, and then cooled to prepare an Ni-SA catalyst tablet. The sizes of NiO crystals of a commercial Pricat catalyst and the Ni-SA catalyst prepared in this study were $35{\AA}$ and $38{\AA}$, respectively. The pore volume and pore size of the Ni-SA catalyst was much larger than the pore volume and pore size of the Pricat catalyst. In addition, the average particle size of the Ni-SA catalyst was much smaller than that of the Pricat catalyst. The triglyceride hydrogenation reaction was carried out in a semi-batch reactor using catalysts impregnated with oil and molded into tablets. It was found that the Ni-SA catalyst was superior to the commercial Pricat catalyst in triglyceride hydrogenation, which could be ascribed to the raw material and the products being less influenced by the diffusion resistance in the pores of the Ni-SA catalyst. The Ni-SA catalyst prepared in this study has the potential to replace the Pricat catalyst as a catalyst for use in the commercial process for hydrogenation of triglyceride.

• Journal of Soil and Groundwater Environment
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• v.17 no.5
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• pp.49-55
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• 2012

A 1.28 L-batch reactor and continuous-flow stirred tank reactor (CFSTR) fed with formate and trichloroethene (TCE) were operated for 120 days and 56 days, respectively, to study the effect of formate as electron donor on anaerobic reductive dechlorination (ARD) of TCE to cis-1,2-dichloroethylene (c-DCE), vinyl chloride (VC), and ethylene (ETH). In batch reactor, injected 60 ${\mu}mol$ TCE was completely degraded in the presence of 20% hydrogen gas ($H_2$) in less than 8 days by anaerobic dechlorination mixed-culture (300 mg-soluble protein), Evanite Culture with ability to completely degrade tetrachloroethene (PCE) and -TCE to ETH under anaerobic conditions. Once the formate was used as electron donor instead of hydrogen gas in batch or chemostat system, the TCE-dechlorination rate decreased and acetate production rate increased. It indicates that the concentration of hydrogen produced in both systems is possibly more close to threshold for homoacetogenesis process. Soluble protein concentration of Evanite culture during the batch test increased from 300 mg to 688 mg for 120 days. Through the protein monitoring, we confirmed an increase of microbial population during the reactor operation. In CFSTR test, TCE was fed continuously at 9.9 ppm (75.38 ${\mu}mol/L$) and the influent formate feed concentration increased stepwise from 1.3 mmol/L to 14.3 mmol/L. Injected TCE was accumulated at 18 days of HRT, but TCE was completely degraded at 36 days of HRT without accumulation of the injected-TCE during the left of experiment period, getting $H_2$ from fermentative hydrogen production of injected formate. Although c-DCE was also accumulated for 23 days after beginning of CFSTR operation, it reached steady-state in the presence of excessive formate. We also evaluated microbial dynamic of the culture at different chemical state in the reactor by DGGE (denaturing gradient gel electrophoresis).

• KSBB Journal
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• v.11 no.2
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• pp.211-217
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• 1996

Batch experiments were conducted to investigate the effect of electron donor on reductive dechlorination of 2,4,5-trichlorophenol by a methanogenic consortium. The methanogenic consortium was obtained from the anaerobic digester of a municipal wastewater treatment plant. The batch reactor containing methanogenic consortium was spiked with 2,4,6-trichlorophenol at 10 mg/$\ell$. Acetate, ethanol, glucose of methanol, each was added as an electron donor for methanogenic consortium. During the course of the experiments liquid samples were taken from the batch reactor to measure dechlorination rate and find the dechlorination pathway of 2,4,6-trichlorophenol. After incubation 2,4,6-trichlorophenol was first dechlorinated to 2,4-dichlorophenol and then to 4-chlorophenol. Phenol was not detected in the batch reactor the highest rate of dechlorination of 2,4,6-trichlorophenol was observed when ethanol was used as an electron donor.

• Membrane Journal
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• v.10 no.2
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• pp.83-91
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• 2000

In order to improve functional properties, enzymatic hydrolysis of FPC (fish protein concentration) was achieved in ultrafiltration membrane reactor (MWCO 5,000). First, insoluble FPC was hydrolyzed by pepsin in batch reactor to decrease the fouling in ultrafiltration membrane reactor, and second hydrolysis was achieved by pronase E in ultrafiltration membrane reactor The optimum operating conditions in batch reactor using pepsin were at temperature 45$^{\circ}C$, pH 2.0 and the ratio of substrate to pepsin, 150 (w/w) After operating for 5hrs under optimum conditions, 89％ of total amount of initial FPC was hydrolyzed. The rate constants, $K_{m}$ and V$_{max}$, were 1.25％ and 0.89 mg/$m\ell$/min, respectively, and substrate inhibition was occured above 1.5％. The ultrafiltration membrane reactor was operated with recycling rate of 474 $m\ell$/min and transmembrane pressure of 15 psi. The permeate flux was increased by temperature, transmembrane pressure, but the permeate flux was fixed by pH. The optimum ratio of substrate to pronase E was 200(w/w) and the productivity of ultrafiltration membarane reactor was 702 mg/mg -enzyme, that of batch reactor was 51mg/mg-enzyme. Molecular weight distributions tot first and second hydrolysates were from 2,500 Da to 20,000 Da and from 700 Da to 10,000 Da, respectivelyly.

• Journal of Microbiology and Biotechnology
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• v.3 no.1
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• pp.39-45
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• 1993

The effect of concentrations of phosphate buffer and acrylonitrile, pH, and various salts on the operational stability of the immobilized cells of Brevibacterium CH2 in a packed bed reactor were investigated. The effects of salts and carriers on the swelling of the immobilized beads during hydrolysis in a columnreactor were also investigated. Immobilization of the cells in Ba-alginate was more desirable than those in polyacrylamide and Ca-alinate for the swelling of the immobilized beads and the desired quality of the acrylamide produced. High quality acrylamide was produced using the Ba-alginate beads in a recycle fed-batch reactor without using an isotonic substrate. The conversion yield was nearly 100％, including a trace amount of acrylic acid produced as a by-product.

• Environmental Engineering Research
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• v.10 no.5
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• pp.257-263
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• 2005

A batch and a continuous type experiments were conducted to test the conditions for simultaneous phosphorus release and uptake, and denitrification, taking place in one process. The bacteria able to denitrify as well as to remove phosphorus were evaluated for the application to biological nutrient removal(BNR) process. In the batch-type experiment, simultaneous reactions of phosphorus release and uptake, and also denitrification were observed under anoxic condition with high organic and nitrate loading. However the rate and the degree of P release were lower than that occurred under anaerobic condition. BNR processes composed of anaerobic-anoxic-oxic(AXO), anoxic-anaerobic-oxic(XAO) and anoxic-oxic(XO) were operated in continuous condition. The anoxic reactors in each process received nitrate loading. In the AXO process, P release in anaerobic reactor and the luxury uptake in oxic reactor proceeded actively regardless to nitrate loading. However in XAO and XO processes, P release and luxury uptake occurred only with the nitrate loading less than $0.07\;kg{NO_3}^--N$/kgMLSS-d. With higher nitrate load, P release increased and the luxury uptake decreased. Therefore, it appeared that the application of denitrifying phosphorus-removing bacteria (DPB) to BNR process must first resolve the problem with decrease of luxury uptake of phosphorus in oxic reactor.

• 수도
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• v.23 no.5 s.80
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• pp.13-22
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• 1996