• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.74-80
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• 1997

This study was performed to estimate the ozonation characteristics of phenol wastewater with increasing pH in the continuous packed column reactor (PCR) and the bubble column reactor (BCR). Among various influencing factors that affect phenol on decomposition through the ozonation, pH was chosen as reaction parameter. Upon increasing pH from 3 to 9, the phenol removal efficiency in PCR was improved approximately by 17% while in BCR approximately by 19.2%. The improvements in the phenol removal efficiency by increasing pH caused the enhancements in ozone utilization efficiency reaching almost 100% in PCR at pH 9. In conclusions, ozone has latent power for phenol wastewater treatment, and the performance of PCR was superior to that of BCR in the aspects of phenol removal and ozone utilization efficiency.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.49-52
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• 1999

A subspace-based identification method of the Wiener model, consisting of a state-space linear block and a polynomial static nonlinearity at the output, is used to retrieve from discrete sample data the accurate information about the nonlinear dynamics. Wiener model may be incorporated into model predictive control (MPC) schemes in a unique way which effectively removes the nonlinearity from the control problem, preserving many of the favorable properties of linear MPC. The control performance is evaluated with simulation studies where the original first-principles model for a continuous MMA polymerization reactor is used as the true process while the identified Wiener model is used for the control purpose. On the basis of the simulation results, it is demonstrated that, despite the existence of unmeasured disturbance, the controller performed quite satisfactorily for the control of polymer qualities with constraints.

• Journal of environmental and Sanitary engineering
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• v.13 no.1
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• pp.174-184
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• 1998

Biosorption characteristics were investigated to discuss the use of agar entrapped Spirulina to remove of heavy metal ions from polluted waters. Agar immobilized algae were used as bioadsorbent in continuous reactor for heavy metal ions removal. The process solution contains Pb, Cu, and Cd as single ion and binary ions. In the adsorption of single heavy metal ions by agar immobilized Spirulina, the adsorption reached within 1hr and observed diffusion limitation differed from the free algal cell adsorption. The optimum pH for the adsorption of heavy metals was 4.5 but the influence of pH decreased less than that of free algal cell. Also, the adsorption characteristics of single heavy metal ions with agar immobilized Spirulina fitted the BET isotherm. Both of experiments of free algal cell and agar immobilized algae showed higher removal efficiency in the single ion solutions than binary ions solutions. The experimental results in the packed column with agar immobilized algae were over 90% of removal efficiency for the Pb, Cu, and Cd in single ion solutions.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.501-506
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• 1998

A mathematical model is developed to describe the relationship between the manipulated variables (e.g. jacket inlet temperature and feed flow rate) and the important qualities (e.g conversion and weight average molecular weight (Mw)) in a continuous polymerization reactor. The subspace-based identification method for Wiener model is used to retrieve from the discrete sample data the accurate information about both the structure and initial parameter estimates for iterative parameter optimization methods. The comparison of the output of the identified Wiener model with the outputs of a non-linear plant model shows a fairly satisfactory degree of accordance.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.3
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• pp.124-130
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• 1997

Wastewater containing phenol was treated using Pseudomonas sp. B3 in continuous reactor, reaction characteristics and kinetics according to variation of volumetric loading rate in continuous reactor were studied. The removal efficiencies of phenol were more than 99% at the whole range of experiment, and those of COD were 97% at the volumetric loading rate, $0.96kg/m^3{\cdot}d$ and 88% at $3.0kg/m^3{\cdot}d$, respectively. Kinetics constants of $q_m$, $K_s$, Y and $K_d$ were obtained 0.901 l/d, 0.620mg/l, 0.659 and 0.219 l/d, respectively. As compared with to constants of standard activated sludge process, these constants were remarkably different because of toxicity and inhibition of phenol to microbes. And also, kinetics constants of oxygen utilization, a, and b, were shown 0.384 kg $O_2/kg$ phenol and 0.029 l/d.

• Journal of the Korean Mathematical Society
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• v.58 no.1
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• pp.45-67
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• 2021

In this paper, a mathematical dynamical system involving both deterministic (with or without delay) and stochastic "SIR" epidemic model with nonlinear incidence rate in a continuous reactor is considered. A profound qualitative analysis is given. It is proved that, for both deterministic models, if ��d > 1, then the endemic equilibrium is globally asymptotically stable. However, if ��d ≤ 1, then the disease-free equilibrium is globally asymptotically stable. Concerning the stochastic model, the Feller's test combined with the canonical probability method were used in order to conclude on the long-time dynamics of the stochastic model. The results improve and extend the results obtained for the deterministic model in its both forms. It is proved that if ��s > 1, the disease is stochastically permanent with full probability. However, if ��s ≤ 1, then the disease dies out with full probability. Finally, some numerical tests are done in order to validate the obtained results.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.417-417
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• 2012

For desired optical properties of QDs, it is very important to reduce the presence of defects on their surfaces. Passivation of surface defects using larger band gap materials is the most effective way. Some groups successfully synthesized Cd based multi-shell structured quantum dots and improved its optical properties. However, its productivity has limit because of the amounts of glass ware and space. In this research, we try to synthesize Cd based multi-shell structured nanocrystal quantum dots to overcome demerits of conventional batch synthetic method. This reactor composed pump, SUS reaction part (3.2 mm stainless steel and furnace) and batch mixer. We successively synthesized CdSe/CdS/ZnS quantum dot at this reactor in one step.

• Journal of Environmental Health Sciences
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• v.28 no.3
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• pp.55-63
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• 2002

This study was carried out to treat textile wastewater using anaerobic sludge and aerobic fixed-bed biofilm reactor immobilized with Bacillus sp. dominated activated sludge(Bacillus sp. fraction : 81.5%). The range of influent con-centration of SCOD and soluble color were 1032-1507 mg/1, and 1239-1854 degree, respectively. Continuous treatment experiments were performed with variation of textile wastewater ratio at a same HRT. When textile wastewater ratio was 100%(HRT : 24 hours), The removal efficiency of SCOD and soluble color were 88% and 78%, respectively. When compare aerobic reactor of this study that was immobilized with Bacillus sp. dominated activated sludge to other study that was immobilized with activated sludge, SCOD and soluble color removal efficiency of this study showed a little higher efficiency than immobilized with activated sludge. The Bacillus sp. fraction of initial condition was 81.5%), but the fraction after operation was decreased to 31.8%).

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.931-936
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• 1992

In operational pont of view, the batch reactor is quite different from the continuous reactor in that it is completely in unsteady states. This makes process variables swing over wide ranges and the process disclose its nonlinerarities. For the most part these nonlinearities are due to reaction heat. Accordingly it is very important to know the informations of reaction heat. This paper presents the method of reaction heat measurement in industrial batch reator which furnishes the limited measurable points. The informations of reaction heat are utilized in modeling of the batch reactor as well as deciding the stability and control variables.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.605-610
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• 1997

A simple dynamic model is developed for the transient simulation of the nuclear power reactor. The dynamic model includes the normalized neutron kinetics model with reactivity feedback effects and the core thermal-hydraulics model. The main objective of this paper demonstrates the capability of the developed dynamic model to simulate various important variables of interest for a nuclear power reactor transient. Some representative results of transient simulations show the expected trends in all cases, even though no available data for comparison. In this work transient simulations are performed on a microcomputer using the DESIRE/N96T continuous system simulation language which is applicable to nuclear power reactor transient analysis.