• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.5
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• pp.509-515
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• 2012

In this study, ${\gamma}-Al_2O_3$ nanoparticles were synthesized by using coflow hydrogen diffusion flames. The synthesis conditions were varied with using several oxygen concentrations in the oxidizing air. The particle characteristics of the flame-synthesized $Al_2O_3$ nanoparticles were determined by examining the crystalline structure, shape, and specific surface area of the nanoparticles. The measured maximum centerline temperature of the flames ranged from 1507.8 K to 1998.7 K. The morphology and crystal structure of the $Al_2O_3$ nanoparticles were determined from SEM images and XRD analyses, respectively. The particle sizes were calculated from measured BET specific surface areas and ranged from 25 nm to 52 nm. From XRD analyses, it was inferred that a large number of the synthesized nanoparticles were ${\gamma}-Al_2O_3$ nanoparticles including ${\theta}-Al_2O_3$ nanoparticles.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.798-803
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• 2015

This study was conducted to predict the effect of door opening in wooden cultural heritages (WCHs) on their conservation environment. For this prediction, measured relative humidity (RH) and surface wood moisture content (MC) of inner part of wood columns in open wooden building and neighboring closed wooden building were compared with minimum RH, including the duration of minimum RH, and MC required for spore germination and resultant growth of wood-degrading fungi reported in some literatures. Moisture conditions, namely RH of inside wooden building and MC of wood was unsuitable for decay and sap-stain fungi all the year round; however, moisture conditions during summer season was suitable for spore germination and resultant growth of surface mold fungi, regardless of door opening. When compared, the duration of minimum (75%) or higher RH and the number of wood columns with MC level greater than the minimum MC (15%) during summer season, the surface mold related to the conservation environment of inside wooden building was somewhat better in open building than in closed building. Rather, doors should be opened in closed building for reducing indoor RH as a necessary measure during summer season when outdoor RH is high.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.9-14
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• 2020

Four developed patents have applied for a new type of Composite Cyclone Scrubber followed by the previous research (Cho and Kim, 2017), including dust reducing fan with filters. Regarding target installation and maintenance cost, 64% reduction for investment costs (6.2 billion won vs. 17 billion won) compared to existing road pollution reduction system, while social benefit costs increase by 43% compared to existing road pollution reduction measures (72.6 billion won vs. 50.8 billion won). The composition of the device is an air blower type spiral guide vane, and an injection pressure collecting dust efficiency. A nozzle varies Injection angle and contact range, spray liquid species (waterworks, salty water). The proposed patent tests are circulation water Time-by-Time Spray and collected 41.4% more increased micro dust since the sprayed water meets contaminated gas due to the 45° degree colliding, which is 141% increased conventional dust collector. (Ratio of collection over 85%). As regards the source of collection liquid, circulated rainwater and well water, we expect a huge amount of energy and economically saved eco-friendly system in our patent. Finally, the guided vane and metal filter reduced over 90% micro-dust, while sprayed water cleans the vane and filters, resultantly minimizing the maintenance budget. The preliminary evaluations of the developed design make it possible to reduce not only cheaper maintenance budget due to the characteristic water spraying but the cost of water comes from mainly rain and underground.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.31-39
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• 2017

The fundamental study for an application of nanobubble as a soil remediation enhancer on heavy metal contaminated soil was carried out. The existence and long-term stability of hydrogen nanobubbles were investigated by particle analysis and zeta-potential analysis. And the removal efficiency of copper using nanobubble water(NBW) and distilled water(DW) were compared and analyzed through a batch desorption test. As a result, it is confirmed that nanobubble which was fabricated by compression-dissolution type generator can exist for more than 14 days. The results of batch test show that copper removal of NBW was higher than that of DW irrespectively to soil type and increased as solid-liquid ratio and contact time increased, respectively. According to the pH change, the removal of copper on sand was higher on the acid side but the removal difference was slightly lower on the clay. It is considered that a high efficiency of NBW in copper removal is due to the large surface area and high zeta-potential of nanobubbles. Therefore, the nanobubble can be applied to soil remediation for heavy-metal contaminated soil as an eco-friendly enhancer.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.29-34
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• 2009

For several decades, many researchers have been involved in developing recycling methods for FRP boats. There are four basic classes of recycling covered in the literature. Despite of environmental problems(safety hazards), mechanical recycling of FRP boats, which involves shredding and grinding of the scrap FRP, is one of the simpler and more technically proven methods than incineration, reclamation or chemical ones. Because FRP is made up of reinforced fiber glass, it is very difficult to break into pieces. It also leads to secondary problem in recycling process, such as air pollution and unacceptable shredding noise level. Another serious problem of mechanical FRP recycling is very limited reusable applications for the residue. This study is to propose a new and efficient method which is more wide range applications and environment friendly waste FRP regenerating system. New system is added with the cyclone sorting machine for airborne pollutions and modified cutting system for several glass fiber chips sizes. It also has shown the FRP chip fiber-reinforced concrete and fiber-reinforced secondary concrete applications with the waste FRP boat to be more eligible than existing recycling method.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.23-28
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• 2009

There is several ways of recycling methods for waste FRP boats. The main one is mechanical recycling that is one of the simple and technically proven methods. It recently has been reported that FRP can be recycled by separating into laminated glass fiber layers instead of crushing into powder. Even though the mechanical recycling is a good way for the eligibility of laminated glass fiber reinforced material, the system should have another option which can collect resin of FRP. Because the resin is still very useful renewable energy source, that cannot be discarded, But FRP is made up of laminated glass fiber(roving cloth layer) which is fire retardant substances and very hard to break into each layer. Due to the high cost of fossil energy the waste plastics should be regenerated to the source of renewable energy. Laminated glass fiber which is recyclable in a very limited way, is currently a serious barrier to waste FRP boat regenerating. This study is to propose a new extracting method which is efficient and environment friendly FRP waste regenerating system. The recycled glass fiber which is obtained by the separation of the roving layer from FRP waste has been found to be useful for concrete(FRC) products or concrete(FRC) structures as fiber reinforced material. And it can be successively applied to renewable energy applications using the waste resins of FRP residue without laminated glass fiber.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.272-278
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• 2016

Porous pavements are recommended as a Low-Impact Development (LID) method which is a strategy to develop a water cycle as close to a natural state as possible, and to solve the urban impervious surface problems. Porous pavements can yield a solution if it provides a more permeable surface with extra space to contain extra water from building roofs. But there are few applications in Korea because of a lack of recognition and experience. Highway engineers are mainly concerned about the infiltration of water into pavement structures. They worry about the weakening of the asphalt mixture and subgrade, and freezing during the winter season due to the infiltration of water. Meanwhile, hydrological experts doubt the effects of the amount of water to control during the flooding season, and environmental experts prefer a non-point pollution treatment system established beside highway. In this study, from reviewing the history and the body of literature about porous pavements, conclusions regarding the most advanced technologies were made. First, traditional thickness designs can be used for porous pavement, no extra distresses was found by weakening and freezing during the winter season. Second, hydrological design can be made by controlling the thickness of the pavement and the outlet of water. Third, the treatment efficiency of non-point pollution of porous pavements is not worse than any other method. Importantly, it's a more eco-friendly solution because of its lower requirement for de-icing agents.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.5
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• pp.51-60
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• 2015

In Korea, 69.4 % of duck farms had utilized conventional plastic greenhouses. In this facilities, there are difficulties in controlling indoor environments for raising duck. High rearing density in duct farms also made the environmental control difficult resulting in getting more stressed making their immune system weaker. Therefore, a facility is needed to having structurally enough solidity and high efficiency on the environmental control. So, new design plans of duck house have recently been conducted by National Institute of Animal Science in Korea. As a study in advance to establish standard, computational fluid dynamics (CFD) was used to estimate the aerodynamic problems according to the designs by means of overall and regional ventilation efficiencies quantitatively and qualitatively. Tracer gas decay (TGD) method was used to calculate ventilation rate according to the structural characteristics of duck houses including installation of indoor circulation fan. The results showed that natural ventilation rate was averagely 164 % higher than typically designed ventilation rate, 1 AER ($min^{-1}$). Meanwhile, mechanically ventilated duck houses made 81.2 % of summer ventilation rate requirement. Therefore, it is urgent to develop a new duck house considering more structural safety as well as higher efficiency of environmental control.

• Journal of Animal Science and Technology
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• v.53 no.5
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• pp.435-440
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• 2011

In this experiment, two inclusion levels (15 and 30% of diets, as-fed basis) of brown rice (BR) were tested against a control diet with 0% BR (51% wheat flour of diet). Six female Maltese (8~9 months age, initial mean body weight of $2.8{\pm}0.3$ kg) were assigned to treatments in replicated $3{\times}3$ Latin square design. Total tract digestibilities of DM, OM, acid hydrolyzed fat, CP and gross energy by dogs fed experimental diets responded quadratically (P<0.01 or <0.05) to BR inclusion levels. Similarly, quadratic responses (P<0.001, P=0.015) were observed for digestible energy and metabolizable energy values, respectively. Wet and dry fecal output also exhibited quadratic responses (P=0.006, P=0.014, respectively) but no differences were observed between control and BR 30% diets. Linear (P=0.008) effect was observed for fecal score in dogs fed BR, and fecal ammonia concentration increased linearly (P=0.001) in response to increasing BR inclusion levels. It seems that the increase in fecal ammonia concentration may be partially related to the decrease tendency (P=0.07) in short-chain fatty acid concentration. In this experiment, inclusion of BR in dog diet did not result in pronounced changes in the digestibility but in fecal score. Although inclusion of BR in diets showed profound positive effect on fecal score, it is confounded by the high inclusion level of poultry offal meal.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.4
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• pp.119-132
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• 2012

The unmanaged abandoned concrete roads are vulnerable toward the issues on soil and water pollution, which requires flexible managing method such as eco-corridor after the process of ecological restoration. Among various alternations of abandoned concrete-paved roads, ecological restoration technique may be the most suitable method in sites including high quality of natural environment. Therefore, as in Young dong province, GyungBu express highway (227.24~229.04km), which is near to Hwang-gan IC, the survey to measure its effect of soil under the paving and water pollution by abandoned concrete roads was discussed. Then, the restoration method of plantings of landscape trees and hydro-seeding methods of artificial soil media was appraised through consecutive monitoring. The soil adequacy analysis shows lower percentage of heavy metal substance in each depth level compared to standard limit stated by the Ministry of Environment, along with low concerns raised after the analysis on heavy metal content of the spilled water on the concrete roads. Meanwhile, Korean Weigela (Weigela subsessilis L.H. Baily) was found to be withered in small-scale landscape trees planting sites. Among the seeding plants. the family of leguminosae, Silene armeria, Dendranthema boreale, Caryopteris incana and Aster yomena show good establishment results. Overall studies on planting of small and large landscape trees, planting method of container plants, planting method of ground cover plants, and germination and development trend of seeding plants of the experimental restoration site on abandoned concrete roads are revealing specific trends in the way landscape woody plants establishment and growth. Finally, this study suggests further studies and survey on varied plant restoration methods on abandoned concrete-roads for developed design guidelines of their methods.