• Carbon letters
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• v.1 no.2
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• pp.82-86
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• 2000

The present research was undertaken to evaluate the possibility of water purification filter with activated carbon fibers (ACFs) using a very low cost precursor consisting of phenolic resin coated on glass fibers. The simplified procedure involving coating, curing and activation and a very low cost glass fiber as a raw material were adopted in order to reduce manufacturing cost. The breakthrough curves of the manufactured ACFs and the commercial activated carbon (AC, Calgon F-200) were investigated in the initial concentration range from 19 to 49 ppm for benzene, toluene and ethylbenzene. From breakthrough profiles, the manufactured ACFs had significantly faster adsorption kinetics than the AC. Especially the benzene breakthrough curves, the manufactured ACF (13 g of ACF with 32% of carbon on the glass) was over the limited level (5 ppb) after flowing of 32 l at initial concentration of 15 ppm, while the commercial AC was shown about 3 ppm in initial adsorption.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.643-649
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• 2011

Degradation of benzothiophene(BT) in the aqueous phase by potassium ferrate(VI) was investigated. Potassium ferrate(VI) was prepared by the wet oxidation method. The degradation efficiency of BT was measured at various values of pH, ferrate(VI) dosage and initial concentration of BT. BT was degraded rapidly within 30 seconds by ferrate(VI). While the highest degradation efficiency was achieved at pH 5, the lowest degradation efficiency was achieved at pH 9. Also, the initial rate constant of BT increased with decreasing of the BT initial concentration. In addition, the intermediate analysis for the reaction of BT and ferrate(VI) has been conducted using GC-MS. Benzene, styrene, benzaldehyde, formaldehyde, benzoic acid, formic acid, and acetic acid were identified as reaction intermediates, and ${SO_4}^{2-}$ was identified as an end product.

• Journal of Hydrogen and New Energy
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• v.29 no.5
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• pp.427-433
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• 2018

This study was performed to evaluate initial pH and substrate concentration on hydrogen fermentation of protein. The optimum initial pH and substrate concentration of hydrogen fermentation using protein was 8.0 and 1.0 g peptone/L, respectively. The maximum hydrogen yield at initial pH 8.0 and 1.0 g peptone/L was $19.2{\pm}0.8mL\;H_2/g$ peptone. As results of VFAs analysis, percentages of valerate was similar to hydrogen yield. Also, C. stickalandii, which was hydrogen and valerate producing bacteria, was dominated.

• Journal of the Korean Society of Safety
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• v.7 no.3
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• pp.66-72
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• 1992

An experimental study was carried out to analyse the explosion characteristics of flammable gas-air mixtures. Used flammable gases were hydrogen, methane, acethylene, ethylene and pro-pane, explosion Pressure, explosoin pressure rising rate, and flame propagation velocity were measured experimentaly. The maximum explosion pressure and rising rate of flammmalbe gas air mixtures were appeared at the range of slightly higher concentration than the stoichiometric concentration. Initial pressure before explosion was controlled from 0.6 to 2.0kg/cm absolutly. Explosion pressure was increased with increment of the initial pressure, and the relationship between initial pressure and explosion pressure was Pe = KPi. The effect of vessel size on explosion characteristics was also analysed In this experiment. Explosion pressure was increased with in-creasing the vessel size, otherwise explosion pressure rising rate was decreased. When we locate a dummy material in vessel explosion pressure was decreased with increasing the dummy volume but exlosion pressure rising rate was increased.

• KSBB Journal
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• v.6 no.2
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• pp.207-213
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• 1991

In this study poly (1-methyl-4-vinylpyridinium iodide-co-styrene) membrane with pyridinium cation as a fixed carrier was synthesized and the transport characteristics of the membrane was examined over various factors. As the concentration of the fixed carrier in the membrane was increased, the water content was increased. Meanwhile, the counter current of the organic anion and the chloride ion, the following results were obtained. Initial flux of Cl-, organic anion and Na+ decreased with the increasing thickness of membrane, and as the concentration of the fixed carrier increases, the initial flux of Cl- and organic anion increase but the initial flux of Na+ decreased. The flux equation of the organic anion, CCl3COO- was obtained from saturation kinetics as follows;$V_{o}=\frac{(8.67{\times}10^{-5}){\cdot}[NaCl]}{9.63{\times}10^{-2}+[NaCl]} mol/cm^2h$

• Journal of Korean Society of Water and Wastewater
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• v.25 no.1
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• pp.63-74
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• 2011

The degradation characteristics of 2-chlorophenol(2-CP) by Ferrate(VI) were studied. The degradation efficiency of 2-CP in aqueous solution was investigated at various values of pH, Fe(VI) dosage, initial concentration and aqueous solution temperature. The maximum degradation efficiencies of 2-CP were obtained at pH 7.0 and aqueous solution temperature of 25$^{\circ}C$. The degradation efficiency was proportional to dosage of Fe(VI). Also, the initial rate constant of 2-CP degradation increased with decreasing of the 2-CP initial concentration. In addition, the degradation pathway study for 2-CP was conducted with GC-MS analysis. Acetic acid, formic acid, benzaldehyde and benzoic acid were identified as reaction intermediates of the 2-CP degradation by Ferrate(VI).

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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• pp.109-119
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• 2018

The purpose of this study is to evaluate the structural safety of the front-end loader for the 90 kW class of agricultural tractors in impact test conditions. Deformation and stress on the loader under the impact test conditions are analyzed using the commercial finite element analysis software ANSYS. In previous research dealing with the initial design of the loader, the maximum stress occurred in the mount and exceeded the yield strength of the material. In this paper, an improved design of the mount of the loader was proposed to reduce the stress concentration in the initial design. The safety of the improved design was verified by performing rigid-body dynamics analysis, transient structural analysis, and static structural analysis under three impact test conditions: a drop and catch test, a corner pull test, a corner push test. It was found that the local stress concentration in the mount that appeared in the initial design was greatly reduced in the improved design, and that the maximum stresses occurred in the three impact test conditions are smaller than the yield strength. It is expected that the design improvement of the mount proposed in this study and the method of analysis may be effectively used to enhance structural safety in the development of new model front loaders in the future.

• Microbiology and Biotechnology Letters
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• v.13 no.1
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• pp.33-39
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• 1985

The effects of initial concentration, flow rate, and recycle ratio on the removal efficiency of phenol were studied in a tapered fluidized bed reactor packed with activated carbon which was attached with Candida tropicalis. The optimum conditions of Candida tropicalis were showed that pH was 7.0 and temperature was $30^{\circ}C$, and the specific growth rate of Candida tropicalis was satisfied with the Monod equation up to 500 mg/L of phenol, and beyond it the inhibition of substrate was found. According to the increases of initial concentration and flow rate, the removal efficiency was decreased, as the recycle ratio was increased, the removal efficiency was increased. In the case of flow rate of 10mL/sec and the recycle ratio of 2, the removal efficiency was 90% above for the all of initial concentration. The removal rate of phenol was the first order reaction in this system, and the rate equation of reaction was as follows.

• Membrane and Water Treatment
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• v.9 no.1
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• pp.9-15
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• 2018

Coagulation process using aluminum sulfate ($Al_2(SO_4)_3$) and ferric chloride ($FeCl_3$) was employed as a treatment method for decolorization of a synthetic textile wastewater containing red dye in this paper. Factors such as initial pH, coagulant dosage, initial concentration, conductivity and mixing conditions that influence color removal efficiency were experimentally tested. It was found that $Al_2(SO_4)_3$ is more efficient than $FeCl_3$ as coagulant. When $40mgL^{-1}$ aluminum sulfate was used, results showed that color induced by the red dye was efficiently removed (> 90 %) and was obtained in a large range of initial pH from 4 to 8 with, and for a dye concentration lower than $235mg\;L^{-1}$. After addition of the coagulant, the medium had to be mixed for 30 min at 60 rpm, then allowed to settle for 40 min. The effects of water conductivity in the range $0.035-2.42mS\;cm^{-1}$ and dye concentration up to $380mg\;L^{-1}$ were also followed and discussed.

• Journal of Environmental Science International
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• v.18 no.1
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• pp.1-7
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• 2009

In this study a sediment yield is compared by IUSG, IUSG with Kalman filter, tank model and tank model with Kalman filter separately. The IUSG is the distribution of sediment from an instantaneous burst of rainfall producing one unit of runoff. The IUSG, defined as a product of the sediment concentration distribution (SCD) and the instantaneous unit hydrograph (IUH), is known to depend on the characteristics of the effective rainfall. In the IUSG with Kalman filter, the state vector of the watershed sediment yield system is constituted by the IUSG. The initial values of the state vector are assumed as the average of the IUSG values and the initial sediment yield estimated from the average IUSG. A tank model consisting of three tanks was developed for prediction of sediment yield. The sediment yield of each tank was computed by multiplying the total sediment yield by the sediment yield coefficients; the yield was obtained by the product of the runoff of each tank and the sediment concentration in the tank. A tank model with Kalman filter is developed for prediction of sediment yield. The state vector of the system model represents the parameters of the tank model. The initial values of the state vector were estimated by trial and error.