• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.395-401
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• 2004

In this study, lots of methods have been studing to utilize energy and decrease contaminated effluents. There has been great progress on IGCC (Integrated gasification combined cycle) to reduce thermal energy losses. The following results have been conducted from desulfurization experiments using waste shell to remove $H_{2}S$. Unreacted core model ior desulfuriration rate prediction of sorbent was indicated. These were linear relationship between time and conversion. So co-current diffusion resistance was conducted reaction rate controlling step. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfide(CaS) formed. Maximum desulfurization capacity was observed at 0.631 mm for lime, oyster and hard-shelled mussel. The kinetics of the sorption of $H_{2}S$ by CaO is sensitive to the reaction temperature and particle size at $800^{\circ}C$, and the reaction rate of oyster was faster than the calcined limestone at $700^{\circ}C$.

• Environmental Engineering Research
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• v.11 no.5
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• pp.250-256
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• 2006

The combustion kinetics of poly(ethylene terephthalate) (PET) was studied by the dynamic model which accounts for the thermal decomposition of polymer at any time. The kinetic analysis was performed by a conventional nonisothermal thermogravimetric (TG) technique at several heating rates between 10 and 40 K/min in air atmosphere. The thermal decomposition of PET in air atmosphere was found to be a complex process composed of at least two stages for which kinetic values can be calculated. The combustion kinetic analysis of PET gave apparent activation energy for the first stage of $257.3{\sim}269.9\;kJ/mol$, with a value of $140.5{\sim}213.8\;kJ/mol$ for the second stage. To verify the effectiveness of the kinetic analysis method used in this work, the kinetic analysis results were compared with those of various analytical methods. The kinetic parameters were also compared with values of the pyrolysis of PET in nitrogen atmosphere.

• Environmental Engineering Research
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• v.14 no.1
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• pp.26-31
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• 2009

Sorption of $Ni^{2+}$ in aqueous solution was studied using montmorillonite. The experimental and equilibrium data fitted well to the Langmuir isotherm model. From the kinetics data for nickel sorption onto montmorillonite, the diffusion of $Ni^{2+}$ inside the clay particles was the dorminant step controlling the sorption rate and as such more important for $Ni^{2+}$ sorption than the external mass transfer. $Ni^{2+}$ was sorbed due to strong interactions with the active sites of the sorbent and the sorption process tends to follow the pseudo second-order kinetics. Thermodynamic parameters (${\Delta}G^{\circ},\;{\Delta}H^{\circ},\;{\Delta}S^{\circ}$) indicated a non spontaneous and endothermic adsorption process while the positive low value of the entropy change suggests low randomness of the solid/solution interface during the uptake of $Ni^{2+}$ by montmorilionite. Heavy metals such as $Ni^{2+}$ in aqueous bodies can effectively be sorbed by montmorillonite.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.332-337
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• 2003

Enzyme kinetics data play a vital role in the design of reactors and control of processes. In the present study, kinetic studies on pectinases were carried out. Partially purified polymethylgalacturonase (PMG) and polygalacturonase (PG) were the two pectinases studied. The plot of initial rate vs. initial substrate concentration did not follow the conventional Michaelis-Menten kinetics, but substrate inhibition was observed. For PMG, maximum rate was attained at an initial pectin concentration of 3 g/l, whereas maximum rate was attained when the initial substrate concentration of 2.5 g/l of polygalacturonic acid for PG I and PG II. The kinetic data were fitted to five different kinetic models to explain the substrate inhibition effect. Among the five models tested, the combined mechanism of protective diffusion limitation of both high and inhibitory substrate concentrations (semi-empirical model) explained the inhibition data with 96-99% confidence interval.

• Journal of Powder Materials
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• v.5 no.4
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• pp.241-249
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• 1998

Sintering kinetics of ball-milled $MoSi_2$ was studied with the addition of Ni. $MoSi_2$ powder with the average particle size of 1 $\mu\textrm{m}$ was obtained from ball-milling of 10 $\mu\textrm{m}$ powder. Small amount of Ni was added to the ball-milled $MoSi_2$ powder by salt solution and reduction method. The powder was compacted into cylindrical shape at 200 MPa and isothermally sintered in a $H_2$ atmosphere at the temperature range of 1100~$1400^{\circ}C$ for 3~600 minutes. The changes of linear shrinkage and sintered density were monitored as a function of sintering time. The microstructure was observed by using optical microscopy and scanning electron microscopy. Phases were identified by X-ray diffratometer and electro-probe micro analysis. Sintering kinetics of Ni-added powder was compared to as-milled powder and the apparent activation energy was calculated from Arrhenius plot.

• Environmental Engineering Research
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• v.13 no.1
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• pp.28-32
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• 2008

The photocatalytic treatment of water contaminated with 2,4,6-trinitrotoluene (TNT) was explored in bench-scale experiments in batch mode using a Pyrex tube coated with a thin film of $TiO_2$ located inside a photoreactor. The reactor was aerated by purging it with compressed air before initiating the photocatalytic reaction. The rate of TNT degradation approximated first-order kinetics. The reaction rate constant decreased as the TNT concentration increased from 25 to 100 mg/L, while the first-order kinetics could be modeled using a Langmuir adsorption isotherm. The addition of the organic reductants methanol and EDTA significantly enhanced the rate of TNT degradation, with optimum results in the presence of 20% methanol by volume. EDTA increased the rate of TNT removal by enhancing the role of the reductants.

• Journal of the Korean Society of Combustion
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• v.13 no.1
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• pp.17-22
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• 2008

A partly implicit/quasi-explicit method is introduced for the solution of detailed chemical kinetics with stiff source terms based on the standard fourth-order Runge-Kutta scheme. Present method solves implicitly only the stiff reaction rate equations, whereas the others explicitly. The stiff equations are selected based on the survey of the chemical Jaconian matrix and its Eigenvalues. As an application of the present method constant pressure combustion was analyzed by a detailed mechanism of hydrogen-air combustion with NOx chemistry. The sensitivity analysis reveals that only the 4 species in NOx chemistry has strong stiffness and should be solved implicitly among the 13 species. The implicit solution of the 4 species successfully predicts the entire process with same accuracy and efficiency at half the price.

• Macromolecular Research
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• v.15 no.6
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• pp.560-564
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• 2007

The photostabilization and cure kinetics of UV-curable, optical resins containing various formulations of photostabilizers were investigated to determine the system with the highest cure conversion and durability. Photo-DSC analysis revealed that increasing the concentration of a UV absorber (UVA) decreased both the crosslink density and the cure rate due to competition for the incident photons between the photoinitiator and the UVA, whereas including a hindered amine light stabilizer (HALS) hardly affected either the cure conversion or the cure rate due to its very low absorption of 365 nm. This result was confirmed by FTIR-ATR spectroscopy and UV-visible spectroscopy analyses. QUV ageing experiments showed that the cure conversion and durability were the highest for the UVA/HALS formulation at a ratio of 1 : 2, which is due to their synergistic action.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.31-35
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• 2011

Factors influencing penetration kinetics of PVAm solution into paper were investigated with ultrasonic Penetration Evenness Analyzer (PEA). Paper structure was varied by changing basis weight, freeness of pulp, calendering, number of plies and filler addition and hydrophobicity of paper was varied by adding AKD. Important factors affecting liquid penetration are found to be pore structure and hydrophobicity of paper. Pore structure of paper can be designed by controlling refining degree and filler addition. Hydrophobicity of paper can be controlled by internal sizing.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.589-594
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• 1993

This paper presents a fault detection strategy that discriminates the faulty sensor and that detects the component fault using a bank of observers for the system in which sensor fault and component fault can occur simultaneously. Observers as many as the number of measurements are designed, and each observer uses measurements excluding sequentially one measurement, to estimate the state variables. The faulty sensor can be found out by comparing each state variable from different observer. Next, component fault can be detected by using measurements from the sensors excluding the faulty sensor. The suggested strategy is applied to a nonisothermal, series reaction with unknown reaction kinetics in a CSTR. This strategy is found out to perform well even in the case that the sensor and component fault occur simultaneously. Since each observer is designed to be independent of reaction kinetics, this strategy is not affected by the model uncertainty and nonlinearity of the reaction kinetics.