• Journal of the Korean Association of Geographic Information Studies
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• v.1 no.2
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• pp.14-25
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• 1998

The purpose of this paper is to select proposed waste facilities sites after consideration of relative importance of siting factors. From the literature review we have established the siting factors affecting selecting waste facilities sites, and constructed hierarchy of siting factors to evaluate the relative importance of the factors using Analytical Hierarchy Process(AHP). After mail surveying of expert group, we have analyzed the relative importance of siting factors affecting waste facilities. We have constructed Geographic Information System(GIS) of raster type, based on seventeen theme maps of siting factors on waste facilities, to select the proposed waste facilities sites after consideration of the relative importance of the siting factors for Gyongsan city, in Korea. After applying linear combination method, and factor combination method to overcome the methodological limitations of land suitability analysis, we have found five proposed sites, where intersected with proposed sites obtained from the two methods. From this research we have found that 1) methodologically, using GIS for selection of proposed waste facilities sites turned out to be highly useful, 2) application of relative importance of siting factors and two methods of land suitability analysis in selection of proposed waste facilities sites are pertinent enough to provide valid and reliable results, and 3) the research methods and approach employed in this research will be highly useful in site selection of other major facilities.

• The Journal of the Korea Contents Association
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• v.19 no.12
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• pp.68-83
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• 2019

The characteristics of intermediate-level waste treatment services are likely to have a negative effect because they act as a factor in promoting incentives of earnings management in the relationship between financial characteristics and earnings management in companies which are possible for earnings management. The researchers conducting this study attempted to empirically verify relationships between financial characteristics and earnings management against domestic construction waste disposal companies in consideration of the characteristics of intermediate-level waste disposal businesses, and the results are as follows. As construction waste disposal businesses grew larger, and the trade receivables collection period lengthened, the intention to increase profits via real activities strengthened. As the ability to generate cash via sales activities weakened, and the difference between the EBITDA margin and the operating margin was lower than the difference in industrial average ratio, discretionary accruals and earnings management via real activities were greater. In particular, there were differences in the variables of intermediate treatment business characteristics which reveal moderating effects by financial characteristics. This study is meaningful in that the scope of relationships between financial characteristics and earnings management in accounting is expanded to cover the construction waste disposal industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.722-727
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• 2016

In this study, we attempted to reduce the generation of waste acids in the electropolishing process by improving the current efficiency. The optimum conditions of the electropolishing process when using the round bus bar were determined by the Taguchi method. The current density, polishing time, electrolyte temperature and flow rate were selected as the control factors for the current efficiency in the electropolishing process. An orthogonal array was created by considering three levels for each factor and experiments were carried out. The larger-the-better SN ratios were calculated by the Taguchi method. The current density was the most important factor affecting the current efficiency and the polishing time was the least important one. The optimum conditions to minimize the generation of waste acids were a current density of $45A/dm^2$, polishing time of 4 min, electrolyte temperature of $65^{\circ}C$ and flow rate of 7 L/min. The results of the ANOVA confirmed that the effects of the current density, electrolyte temperature and flow rate are significant at the 95% confidence level. The increase in the contact area and contact force afforded by using the round bus bar improved the current efficiency which, in turn, reduced the amount of waste acids generated. Further research is planned to investigate the effect of the type of bus bar on the current efficiency.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.4
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• pp.50-61
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• 2013

In order to generate a renewable energy-Methane, anaerobic systems fed with source separated food waste from university cafeteria were studied. At first, four reactors were evaluated with same feed components; content non-mixing anaerobic reactor without leachate withdrawal/recirculation, content mixing anaerobic reactor without leachate withdrawal/recirculation, content non-mixing anaerobic reactor with leachate withdrawal/recirculation and content mixing anaerobic reactor with leachate withdrawal/recirculation. From the first study, content non-mixing anaerobic reactor with leachate withdrawal/recirculation showed the highest gas production. From further study with this system, it was observed that leachate permeation rate within anaerobic reactor was very important factor for gas generation. The higher permeation rate, the more gas production was observed. It is assumed that 1kg of gas collector weight and C/N ration above 10 in food waste may cause gas consumption in the anaerobic reactor. The gas consumption was estimated by negative pressure build-up at gas collector. The negative pressure build-up must be explained to produce Methane from Food Waste.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.296-302
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• 2006

The kinetics of the thermal-oxidative decomposition of waste polyurethane (PU) according to oxygen concentration has been studied using a non-isothermal thermogravimetric technique at several heating rates from 10 to $50^{\circ}C/min$. A kinetic model accounting for the effects of the oxygen concentration by the differential and integral method based on Arrhenius equation was proposed to describe the thermal-oxidative decomposition of waste PU. To obtain the information on the kinetic parameters such as activation energy, reaction order, and pre-exponential factor, the thermogravimetric analysis curves and its derivatives have been analyzed using the kinetic analysis method proposed in this work. From this work, it was found that reaction orders for oxygen concentration had a negative sign, and activation energy decreased as the oxygen concentration increased. It was also found that the kinetic parameters obtained from the integral method using the single heating rate experiments varied with heating rates. Therefore, it is thought that the differential method using the multiple heating rate experiments more effectively represents the thermal-oxidative decomposition of waste polyurethane.

• Resources Recycling
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• v.29 no.4
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• pp.31-44
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• 2020

Recently, plastic recycling has emerged as a social issue, and its importance is increasing. Therefore, this article reviewed the current status and the future directions of domestic plastic recycling. Plastic recycling is major economic and social problems not only in South Korea but also worldwide and is being treated as an important factor for protecting the environment and for sustainability in the next generation. In particular, China, which has been dealing with a large amount of plastic waste generated around the world, has banned importing plastic waste, therefore, other countries have faced the problem of recycling plastics in their countries. In South Korea, the landfill and incineration of the waste are becoming more difficult by the Framework Act on Resources Circulation, therefore, the recycling and reuse of plastics are a very important.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.50-63
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• 2018

The issue of global warming and environmental pollutant has become an international concern due to the widespread use of fossil fuels, and thus waste heat recovery technologies has become important to improve energy utilization. The global market of power generation system using industrial waste heat is rapidly growing at an average rate of 5% due to its advantage of increasing energy efficiency. In order to design an optimal waste heat recovery system, it is necessary to develop a program that offers economic evaluation of each power generating technology according to the heat source conditions. In this paper, the economic analysis module to calculate LCOE is developed and verified the reliability against NETL economic analysis results. As a result of the verification, the error rate is about 6 ~ 7%, which satisfy the accuracy for business feasibility evaluation. In order to enhance the reliability, the module was improved by applying the levelization method used by NETL. As a result of the verification of reliability, the error rate is less than 1% and the accuracy is improved.

• Journal of Korean Society of societal Security
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• v.2 no.2
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• pp.69-74
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• 2009

The purpose of this research is to assess the aseismic safety for the large-sized waste landfill site based on the results from liquefaction potential analysis. For successful achievement of research, the simplified liquefaction analysis and detailed liquefaction analysis using data from lab test and seismic response analysis are executed. Based on the simplified liquefaction analysis, the possibility of liquefaction is occurred at only BH-14 with maximum acceleration 0.169 g. Therefore, liquefaction possibility of BH-14 is evaluated by the detailed liquefaction analysis again. The safety factor greater than 1.0 from the result of analysis at BH-14 guarantees safety of liquefaction.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.1
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• pp.19-26
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• 2016

This study was performed to evaluate the strength and durability properties of modified epoxy composites with waste tire chip, recycled coarse aggregate, filler and modified epoxy to improve elongation and elasticity of epoxy. Additionally, for comparing to modified epoxy and unsaturated polyester resin as a binder, unsaturated polyester resin composites were developed in the same condition. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate size and binder content. Tests for the compressive and flexural strength, freezing and thawing and durability for 20 % sulfuric solution were performed. The compressive and flexural strength of modified epoxy composites were in the range of 34.9~61.6 MPa and 10.2~18.3 MPa at the curing 7 days, respectively. Also, the compressive and flexural strength of unsaturated polyester resin composites were in the range of 44.2~77.8 MPa and 11.3~20.8 MPa at the curing 7 days, respectively. After 300 cycles of freezing and thawing, weight decrease ratio and durability factor of modified epoxy composites were in the range of 0.8~1.9 % and 95~98, respectively. Accordingly, modified epoxy composites will greatly improve the durability of concrete.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.409-412
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• 2010

This study investigated and discussed the drying characteristics of municipal wood wastes (wood, particle board, medium density fiber-board(MDF)) in the $N_2$ environment with an isothermal thermogravimetric analyzer. The drying rate could be expressed by a first order reaction model on remaining fraction of moisture. The activation energy ranged from 12.72 kJ/g mol to 18.31 kJ/g mol and the frequency factor from 0.2155 1/s to 1.249 1/s.