• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2164-2171
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• 2018

Heavy duty diesel vehicles deteriorate urban air quality by discharging a large volume of air pollutants such as soot and nitrogen oxides. In this study, a newly introduced auxiliary device a fuel activation device (FAD) to improve the combustion efficiency of internal engines by utilizing the cavitation effect was closely investigated by the fluid flow mechanism via a numerical analysis method. As a result, the FAD contributed to fuel atomization from the injection nozzle at lower inlet pressure by reducing the pressure energy. The improved cavitation effect facilitated fuel atomization, and ultimately reduced pollutant emission due to the decrease in fuel consumption. The axial velocity along the flow channel was increased 8.7 times with the aid of FAD, which improved the primary break-up of bubbles. The FAD cavitation effect produced 1.09-times larger turbulent bubbles under the same pressure and fuel injection amount than without FAD.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.306-318
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• 2017

Heavy diesel vehicles are one of major sources of urban fine dust in Korea and other developing countries. In this study, an auxiliary device assisting fuel atomization, which is called FAD (Fuel Activation Device), was closely reviewed through numerical simulation. As calculated, the diesel flow velocity passing across FAD increased up to 1.68 times, and it enhanced the cavitation effect which could improve the injected fuel atomization. Super cavitation phenomenon, which is the most important effect on nozzle injection, has occurred until the cavitation number (${\sigma}$) decreased from 1.15 to 1.09, and atomized droplets via a nozzle of which opening was $500{\mu}m$ distributed less than $200{\mu}m$ in sauter mean diameter (SMD).

• Journal of Korean Society of Environmental Engineers
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• v.34 no.4
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• pp.247-253
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• 2012

The objective of this study was to find the frequency that most effectively generates hydroxyl radical and to investigate the effect of solution volume on the oxidation of arsenite (As[III]) under the determined frequency. Based on the cavitation yield for hydrogen peroxide, hydroxyl radical is formed most effectively under the frequency of 300 kHz. The experiment was performed with various solution volumes (334, 690, 1,046, and 1,401 mL) under 300 kHz. Results showed that as solution volume increased, kinetic constant for arsenite oxidation decreased. However, cavitation yield for arsenite decreased in small volumes (334, and 690 mL) but maintained or increased in large volumes (1,046, and 1,401 mL) over a set period of time (10, 30, and 60 min). Based on the kinetic constant result, it is more advantageous to oxidize arsenite in small volumes. However, according to the cavitation yield for arsenite, it is applicable to oxidize arsenite in large volumes over a long period of time.

• The KSFM Journal of Fluid Machinery
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• v.17 no.3
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• pp.52-58
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• 2014

The development of efficient systems for water quality improvement for water sources such as lakes, dams and reservoirs has become a necessity to provide not only a cleaner and safer water to the urban society, but also to provide a cleaner and safer environment for the aquatic organisms living in lakes, dams and reservoirs. This study concentrates on the outlet design and internal flow analysis of an axial flow pump used in a floating type water treatment system completely powered by renewable energy source. The treatment system is designed to raise water from depths of about 3~5m up to the water surface where it is naturally mixed with air as it is released back to the reservoir. The outlet of a typical axial flow pump is modified to suit the floating type water mixer. The performance of the axial flow pump is studied by investigating the internal flow of the system. Results show that the change in outlet shape does not alter the performance of the original pump at the maximum efficiency point as long as the cross sectional area of inlet is the same as the outlet. The axial pump for floating type water treatment system has good cavitation performance in the whole flow passage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3231-3239
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• 2014

After 1970-80's rapid economic and urban development, nowadays the old downtown suffers from the deterioration of physical environment, outflow of its function and cavitation of population. And this phenomenon makes urban regeneration as a new paradigm in urban development. This is the case of Myeongdong area (Jungang-dong, Monsung-dong), old downtown of Cheonan around rail station, in the same way. City government has tried many regeneration/ redevelopment projects on this area but all failed due to lack of feasibility. This study intends to suggest new viable strategic regeneration scheme of this area through research and analysis of TOD development, existing condition and problems. As a result, the area needs to be considered as a node that links bus terminal complex and central market place with walkable street. For regeneration of this area, a strategic development scheme of this area is suggested deploying private capital invested rail station, underground shopping mall, transfer center, culture complex and nature park with Myeongdong street mall.

• Journal of Agricultural Extension & Community Development
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• v.20 no.2
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• pp.407-429
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• 2013

Although rural areas account for more than 80% of the total land area of South Korea, most of them are deteriorated and living environment is inconvenient. In addition, the migration of young generation to urban areas and ageing have reduced the population and caused not only cavitation phenomena of villages but also stagnant communities. As for one of the rural areas, the seat of Myeon Office located in Oesan-myeon, Buyeo-gun, Chungcheongnam-do, this study presented not a plan only for strengthening hub functions but the methodology of the complex development plan in consideration of the regional characteristics in the comprehensive improvement project in seat of Myeon Office. From the perspective of enhancing the function of the seat of Myeon Office, it is inevitable to establish plans based on hardware. However, empowerment of the residents in the targeted areas also works as an important factor. In other words, each project promoted by the plan will be mainly operated by the local residents. Therefore, it is necessary to establish a management system of this. The success or failure of the established plan is based on the accurate survey of the issues of the targeted areas and demand, and this depends on participation and positive response of the residents of the targeted areas. That is, the method as a 'local community network' is required in order to increase the effect of resident participation in the planning area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.214-215
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• 2013

Current competition among companies than regional, the time constraints, it is globalization, Tilt the efforts of many to be operated by building the efficient distribution system to reduce logistics costs and improve customer service it is reality's there. Therefore, the need for industrial complexes environmentally friendly can be cost competitive companies perform cavitation region's increased. To build the distribution center these logistics system through a joint of freight and appropriate policy is required. In particular, efficient operation through the system construction of industrial complexes in the logistics system is very important in terms of friendly low-cost urban logistics, the environment. Since the traffic volume which is Jipufa and utilization of network is transported by a more appropriate technicians and means suitable operating model can efficiency is improved. However, despite these advantages, research network design has not been actively conducted due to the complexity of the problem. Therefore, in this study, by analyzing the logistics system, and presents the operating model through a simulation and basic settings for the model of the logistics complex based on the analysis result, the construction of infrastructure of logistics industry complex it is intended to present the article.