• Clean Technology
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• v.12 no.3
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• pp.138-144
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• 2006

Conversion of methane to synthesis gas in a capacitive rf plasma at low pressure was experimentally studied. In this plasma, electrons which had sufficient energy-level collided with the molecules of methane or oxygen-containing gas, which were than activated and converted to synthesis gas. The effect of input power, various oxygen-containing gas and composition of the gas mixture were investigated. The conversion of methane reached up to 100%. In all cases, hydrogen and carbon oxide were produced as primary products, and other compounds was generated. The conversion of methane and the yield of hydrogen and carbon oxides were increased with increasing the input power. Depending on the oxygen-containing gases, the composition of synthesis gas was varied.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.23-29
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• 2020

In this study, the last 10 years of news data on fine dust was collected and 80 topics are selected through LDA analysis. As a result, weather-related information made up the main words for the topic, and we can see that fine dust becomes a big issue below 10 degrees Celsius. The frequency of exposure to the media and the maximum concentration of fine dust are correlated with positive. Topics related to fine dust reduction measures and the government's comprehensive measures over the past decade, topics related to products such as air purifiers related to fine dust, topics related to policies protecting vulnerable people from fine dust, and topics on fine dust reduction through R&D were found to be major topics. Measures against fine dust as a social issue can be seen to be closely related to the government's policy.

• Clean Technology
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• v.17 no.3
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• pp.225-230
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• 2011

Characteristics of hydrocarbon selective catalytic reduction of NOx using various noble metal catalysts were investigated. The best active metal is Pt, supports are $CeO_2$ and $TiO_2$ by strong interactions between active metals, and 55% of conversion rate of NOx is shown. Pd, Rh and Ag catalysts presented a conversion of less than 20% as active metals, and supports also showed the poor activity compared to $SiO_2$ and $ZrO_2$. Experiments were performed with different types of reducing agents, amount, concentration of oxygen and space velocity in order to investigate the performance of catalysts according to operating conditions. The results confirm that the methane is better than propane as a reducing agent, and as the ratio of methane/nitrogen oxide increases, the catalytic activity increased, as the concentration of oxygen increases and space velocity decreases, the performance of catalysts increased.

• Clean Technology
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• v.20 no.1
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• pp.88-94
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• 2014

During the past decades much attention has been paid to the desulfurization of diesel oil which is important as a source for the fuel cells to prevent the sulfur poisoning of both diesel steam reforming catalyst and electrode of fuel cell. Although alternative desulfurization techniques have been investigated, desulfurization for ultra-low sulfur diesel (ULSD) is still challenged. Therefore, this research focuses on the desulfurization of commercial ULSD for the application to molten carbonate fuel cell (MCFC). Herein, the performances of several kinds of commercial adsorbents based on activated carbons, zeolites, and metal oxides for desulfurization of ULSD were screened. The results showed that metal oxides based materials can feasibly reduce sulfur concentration in ULSD to a level of 0.1 ppmw while activated carbons and zeolites did not reach this level at current conditions.

• Clean Technology
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• v.14 no.3
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• pp.193-203
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• 2008

A surfactant is used to assist the effect of cleaning, dispersibility and adhesion during leather manufacturing process. Existing surfactant for that process includes many hydrophilic groups that may cause problem such as stain, bad water resistance and poor durability, etc. It is potential problem to make high-performance property for future leather market. In this study, we have synthesized the fluorinated surfactant of which property decreases surface tension, increases dispersion, cleaning effect and the better chrome absorption by the high bond energy of C-F to complement weakness that the present alkyl derivative surfactants have. Using fluorinated surfactant, we can confirm that dispersion is increased, chrome absorption ratio is augmented with high osmosis and coherence, chrome content in the tanning waste water is reduced, BOD and COD contents are diminished and physical characteristics are improved.

• Clean Technology
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• v.14 no.3
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• pp.218-223
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• 2008

Decomposition of reactive organic compound dispersed in microemulsion media by hydroxide ions and proton ions generated during electrolysis was tried and the half-lifes for decomposition were compared. Absorbance of p-nitrophenoxide produced from the decomposition of p-nitrophenylacetate (PNPA) was followed to find the rate of decomposition. The applied voltage, temperature, and the amount of substrate were changed to see the effects on the decomposition rate. The advantages of electrolysis in microemulsion system were the high solubilizing capacity of substrate, easy control of decomposition rate, low operation cost, no need for any addition of chemicals, and no byproducts. The mechanism of decomposition and the application to water purification were discussed.

• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.39-43
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• 2009

Gasoline engine have proved its utility in light, medium and heavy duty vehicle in every sector of the world community. The concern about long term availability of petroleum and the increasing threat for the environment by the increasing load of vehicular emission, compel the technology to upgrade itself for meeting the challenges. CNG is environmentally clean alternative to the existing SI Engines with out much change in the hardware. Many researchers have found this as a potential substitute to meet the energy requirement. Higher octane number and higher self ignition temperature make it a good gaseous fuel. Although power output is slightly lesser than the gasoline it's thermal efficiency is better than the gasoline for the same SI Engine. Results showed that reduced CO, hydrocarbon emissions is a favorable outcome, with slight increase in NOx emission when compared with gasoline fuel to dual fuel mode in the existing SI Engines.

• Clean Technology
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• v.16 no.4
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• pp.265-271
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• 2010

The deactivated diesel oxidation catalyst(DOC) was remanufactured by ultrasonic wave treatment with various solutions, followed by active component re-impregnation. The catalytic performance and surface properties of remanufactured DOC were studied at various remanufacturing conditions. The proper ultrasonic-wave cleaning time at various solutions and optimal re-impregnation amounts of active component for the best catalytic performance were investigated. The catalytic performance tests on the conversions of CO and THC(total hydrocarbon) were also carried out at various temperatures by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the catalytic performance of DOC remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acidic/basic solutions and active component re-impregnation method was recovered to 90% level of its activity compared to that of the fresh DOC, which was caused by removing the deactivating materials from the surface of the DOC through the analyses of catalyst performance test and their characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.

• Clean Technology
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• v.15 no.3
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• pp.147-153
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• 2009

Waste three-way catalysts were remanufactured by ultrasonic wave treatment followed by active component re-impregnation and the catalytic activities and surface properties of remanufactured catalysts were measured at various remanufacturing conditions. In case of the catalyst prepared by ultrasonic wave cleaning, the optimal period for elimination of surface contaminants from the waste catalyst was found to be about 5 minutes. The proper re-impregnation amounts of the active components for the best catalytic performance were investigated and the catalytic performance tests were also carried out with various temperature for the total hydrocarbon (THC), carbon monoxide (CO) and nitrogen oxides (NOx) conversions. The experimental results showed that the catalytic performances of the remanufactured catalysts were recovered almost the same level as those of the fresh catalyst except those of the NOx conversion.

• Clean Technology
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• v.16 no.1
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• pp.33-38
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• 2010

The characteristics of desorption reaction and the heating values of used activated carbons collected from the companies of Shiwha/Banwal industrial complex were investigated. The desorption characteristics of used activated carbons were analyzed based on the data obtained from a thermogravimetric analyzer. The activation energies and reaction orders for desorption reaction of used activated carbons were calculated by employing Freeman-Carroll method. Heating values of volatile organic compounds(VOC) desorbed from used activated carbons were estimated based on the data obtained from a total hydrocarbon analyzer. It was found that the reaction orders of desorption of used activated carbons were 0.1~0.8, their desorption activation energies, 6.9~26.4 kJ/mol, and VOC heating values, 0.4~10.7 kcal/kg.