• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.171-178
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• 2008

Metal filter elements were newly introduced to the high temperature filter(HTF) system in the low- and intermediate-level radioactive waste vitrification plant. In order to evaluate the performance of various metal materials as filter media, elements made of AISI 316L, AISI 904L, and Inconel 600 were included to the test set of filter elements. At the visual inspection to the elements performed after completion of each test, a few dark spots were observed on the surface of some elements. Especially they were found much more at the AISI 316L elements than others. To check the dark spots are the corrosion phenomena or not, two kinds of analyses were performed to the tested filter elements. Firstly, the surfaces or the cross sections of filter specimens cut out from both normal area and dark spot area of elements were analyzed by SEM/EDS. The results showed that the dark spots were not evidences of corrosion but the deposition of sodium, sulfur and silica compounds volatilized from waste or molten glass. Secondly, the ring tensile strength were analyzed for the ring-shape filter specimens cut out from each kind of element. The result obtained from the strength tested showed no evidence of corrosion as well. Conclusionally, depending on the two kinds of analysis, no evidences of corrosion were found at the tested metal filter elements. But the dark spots formed on the surface could reduce the effective filtering area and increase the overall pressure drop of HTF system. Thus, continuous heating inside filter housing up to dew point will be required normally. And a few long-period test should be followed for the exact evaluation of corrosion of the metal filter elements.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.8-18
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• 2012

Urban nature plays an important role not only in the improvement of the physical environment but also from the perspective of psychological and social function. In particular, schoolyards as well as the green spaces near school surroundings function as a primary space for urban children to experience nature in Korea, as they spend most of their time at school. In this study, the status of urban green spaces near school surroundings was examined. For the analysis, 185 elementary schools in Seoul were selected and the green spaces within a radius of 300m(defined as 'school zone' in this study) were analyzed using the Rapid Eye multispectral satellite image data. The mean green space ratio of school zone accounts to about 21% with a high variation from 74% to 0.7% and more than half of the school zone have a green space ratio of less than 20%. Schools with a high green space ratio in their school zone are mostly located near urban forests, so forest areas particularly contribute to increase the green space ratio. Furthermore, forest vegetation shows relatively higher vitality than other green spaces located in urbanized areas. In contrast, schools with a low green space ratio in their school zone are mostly situated in high-density residential areas and the green spaces show relatively low vegetation vitality. Except for the urban forest, the majority of urban green spaces in urbanized areas are landscape green facilities in apartment districts. The other types of urban open spaces such as environmentally shaped schoolyards or street parks account only for a very small proportion of school surroundings. Therefore, it is needed to establish countermeasures in the context of urban planning; e.g. to promote the school forest projects preferentially by selecting schools with a extremely low green space ratio in their school zone, to foster roof greening in near surroundings, and to connect schoolyards organically with nearby apartment landscape green facilities as an easily accessible urban open space.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.739-747
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• 2011

The major 81 tributaries in Chungcheongnam-do were monitored for flowrate and water quality in order to understand the characteristics of the watershed and to select the tributary catchment for improving water quality. The value of flowrate in the tributaries at Nonsancheon catchment at the Geum-River watershed and Gokgyocheon, Muhancheon, Sapgyocheon at the Sapgyo-Reservoir watershed, which is located in the southern and northern area in Chungcheongnam-do, was relatively greater than the other watersheds. The concentration of water pollutants regardless of water quality parameters in Nonsancheon catchment at the Geum-River watershed, Gokgyocheon catchment at the Sapgyo-Reservoir watershed and the Anseongcheon watershed, which have a dense source of pollution, were higher than the other watersheds. However, 64 percent of the tributaries at the Geum-River watershed, 45 percent of tributaries at the Sapgyo-Reservoir watershed, 26 percent of tributaries at the Geum-River watershed all satisfied the Class II regulations in the Framework Act on Environment Policy, but all of the tributaries located in the Anseongcheon watershed exceeded the Class II regulations. Therefore, the policy for improving the water quality of the tributary in Chungcheongnam-do should be established in the following order: Anseongcheon, Seohae, Sapgyo-Reservoir watersheds. Consequently, the tributary catchment for improving water quality, which has a large flowrate and a high concentration of water pollutants, was selected at Ganggyeongcheon, Geumcheon, Nonsancheon, Seokseongcheon, Seungcheoncheon, Jeongancheon, Jeungsancheon (so far Geum-River watershed), Gokgyocheon, Namwoncheon, Maegokcheon, Muhancheon, Sapgyocheon Oncheoncheon, Cheonancheon (so far Sapgyo-Reservoir watershed), Gwangcheoncheon, Dangjincheon, Daecheoncheon, Dodangcheon, Waryongcheon, Cheongjicheon, Pangyocheon, Heungincheon (so far Seohae watershed), Dunpocheon, Seonghwancheon, Ipjangcheon (so far Anseongcheon watershed). The plans as installation of environmental facilities to reduce the source of pollution for improving the water quality of these tributary catchments should be urgently established and implemented.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.720-728
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• 2012

In general, nonpoint pollutant of a watershed is drained out in the form of storm water runoff during rainfall events. As the bulk of the nonpoint pollutant is in adsorbed form on particulate matters, in order to understand the behavior of nonpoint pollutant it is essential to grasp the characteristics of particulate matters in rainfall runoff. Though, previous studies for the relationship between the runoff characteristics of pollutants and the size distribution of particulate matters are very rare. In this study, a small non-urbanized area (basin area of 52.8 ha) with various landuse types including paddy, dry fields and forest was selected and investigated in detail for the runoff properties of each pollutant during several rainfall events. The correlation and effects between particulate matters and nonpoint pollutant were analyzed quantitatively. As a result, the significant first flush was observed on each event and it became clear that fine particulate matters ($80{\mu}m$ or less) has contributed in the runoff process of nutrients and heavy metals. Organic matters ($BOD_5$, TOC), nutrients (TN, TP) and several heavy metals (Al, Cr, Cu, Fe, Hg and Zn) represented high correlations with SS (total), VSS, SS (d < $20{\mu}m$) and SS ($20{\mu}m$ $$\leq_-$$ d < $80{\mu}m$). On the other hand, $COD_{cr}$, Cd, Mn and Pb did not show clear correlations with the behavior of particulate matters. Therefore, we have to examine the introduction of nonpoint pollution mitigation facilities considering the facts that nonpoint pollutant runoff process has high correlation with the behavior of particulate matters and is changeable based on the target pollutants.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.4
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• pp.213-233
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• 1979

It is generally agreed that the country's population will grow up to the level of 52 million by the year of 2000 and that due the active growth of industry, urbanization and road constructions, sizable portion of existing arable lands will be utilized for other purposes than agriculture in near future. From 1966 to 1977, it was estimated that, the average annual conversion of arable lands to other uses, was 12,909 ha. If this trend persists, it is predicted that from 1978 to 1991 when the 6th Five Years Economic Development Plan will terminate, approximately 181,000 ha of arable lands will be converted for other uses again. On the other hand, it is certain that the increased population (39 million in 1981, 45 million in 1991, 52 million in 2001) and the changes in food pattern along with the enhancement of living standards will bring about the phenomenal increase in demands for not only the staple food but also the livestock products such as meat, milk and eggs, vegetables and fruits. These future increased demands for various foods, naturally mean the increased needs for the expansion of arable lands at the same time. It is predicted that, if more activities than present scale are not taken for the expansion of arable lands, the national food self sufficiency level will drop from 79% in 1977 down to 62% in 1991. To meet the increased food demands in future, there are several ways and means. These will include the increased land use intensity, elevation of unit area yield levels, minimization of conversion of arable lands to other uses and expansion of arable lands through the reclamations of idle hillside lands and tidal lands. Among these, the expansion of arable lands through reclamations of idle hillside lands and tidal lands are more positive measures to cope with the increased production of foods in future. The reclamation of hillside lands demands more attention because it needs more advanced technologies in agronomical and engineering aspects, larger scale fundings and integrated socioeconomic considerations. In agromical aspects, the thechniques for early improvement of chemical and physical properties of soils, proper soil conservation measures and rational cropping systems are of particular importance. As to the financial supports to encourage the farmings in hillside land, much bold fund inputs are essential for the construction of roads, installation of irrigation and drainage facilities, soil conservation mechanisms, which will ensure the stabilized farming with reasonable incomes in the newly reclaimed lands.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.3
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• pp.1-12
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• 2014

Urban Green space takes charge of the important role for the physical activity and promotion of health to the residents. Therefore, this study is trying to examine the relationship between the various characteristics of green space and green space usage for physical activity and health promotion. A questionnaire survey was conducted to obtain the information about patterns of green space usage and perceived neighborhood environments for the residents living in Changwon-si, Gyeongsangnam-do(n=541). Geographic Information System(GIS) was used to construct spatial data about green space accessibility and physical neighborhood environments. A Multiple Linear Regression model was used to examine the association between the characteristics of green space and physical activity, perceived health status and BMI(Body Mass Index). The study results revealed that the residents' physical activities are positively and directly influenced by the number of available public parks and green spaces in the vicinity(${\leq}200m$). The frequency at which residents witness others exercising nearby or the perceived abundance of low-cost gym facilities also factor as positive influences. The closer to the park, the higher the number of parks and area of green spaces, the more comfortable the walk thereto and the denser the neighboring residential area distribution, the perceived health level was found to be the more positively influenced. Further, it was verified that BMI is correlated with the number of public parks and green spaces within 400 m of the resident's home as well as the safety of walkways, the density of neighboring residential areas, the ratio of road, and the density of crosswalk. The significant multiple regression models between the characteristics of green spaces and physical activities and perceived health level were extracted within the significance level of 10%. This study will contribute to provide better understanding the ways in which green space and neighborhood characteristics are associated with physical activity and health. The result of this research will be available in the landscape architecture plan aimed at improving the use of green space for physical activity and reducing obesity.

• The Journal of the Petrological Society of Korea
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• v.25 no.4
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• pp.361-372
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• 2016

Lahar, one of catastrophic events, has the potential to cause the loss of life and damage to infrastructure over inhabited areas. This study using Laharz_py program, was performed schematic prediction on the impact area of lahar hazards at the Mt. Halla volcano, Jeju island. In order to comprehensively address the impact of lahar for the Mt. Halla, two distinct parameters, H/L ratio and lahar volume, were selected to influence variable for Laharz_py simulation. It was carried out on the basis of numerical simulation by estimating a possible lahar volumes of 30,000, 50,000, 70,000, 100,000, 300,000, $500,000m^3$ according to H/L ratios (0.20, 0.22 and 0.25) was applied. Based on the numerical simulations, the area of the proximal hazard zone boundary is gradually decreased with increasing H/L ratio. The number of streams which affected by lahar tended to decrease with increasing H/L ratio. In the case of H/L ratio 0.20, three streams (Gwangryeong stream, Dogeun stream, Han stream) in the Jeju-si area and six streams (Gungsan stream, Hogeun stream, Seohong stream, Donghong stream, Bomok stream, Yeong stream-Hyodon stream) in the Seogwipo-si area are affected. In the case of H/L ratio 0.22, two streams (Gwangryeong stream and Han stream) in the Jeju-si area and five streams (Gungsan stream, Seohong stream, Donghong stream, Bomok stream, Yeong stream-Hyodon stream) in the Seogwipo-si area are affected. And in the case of H/L ratio 0.25, two streams (Gwangryeong stream and Han stream) in the Jeju-si area and one stream (Yeong stream-Hyodon stream) in the Seogwipo-si area are affected. The results of this study will be used as basic data to create a risk map for the direct damage that can be caused due to volcanic hazards arising from Mt. Halla.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.459-469
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• 2015

The effects of elevated spring temperatures on the growth and fruit quality of the mandarin hybrid 'Shiranuhi' [(Citrus unshiu ${\times}$ C. sinensis) ${\times}$ C. reticulata] were investigated in plastic greenhouses, to develop a cropping system to improve the quality of the fruit and increase the income of growers on Jeju Island, South Korea. Under conditions of elevated temperature I ($25/15^{\circ}C$, day/night) and elevated temperature II ($28/18^{\circ}C$, day/night) during early spring, budburst was advanced by 11 and 15 d, and full bloom by 22 and 45 d, respectively, compared to those of the plants grown at ambient air temperature in a plastic greenhouse. Elevated temperatures decreased the number of spring shoots but increased mean spring shoot length and leaf area. Growing 'Shiranuhi' trees at elevated temperatures resulted in increases in mean fruit weight and fruit L/D ratio (> 1.0). In addition, fruit color development was significantly advanced in trees grown under elevated temperatures during early spring, which allowed the fruit to be harvested 1-2 months earlier than trees grown under ambient air temperature. Fruit soluble solids content (SSC) and titratable acidity (TA) at harvest were similar between elevated temperature I and ambient air temperature, but were significantly higher than at elevated temperature II. Considering fruit quality, harvest time, and yield, the elevated temperature treatment regime of $25/15^{\circ}C$ (day/night) during early spring could be useful for cultivation of the mandarin hybrid 'Shiranuhi' to increase the income of growers.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.235-246
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• 2012

Reusing livestock manure have various advantages in securing soil organic resources. In this study, the N-loading and recycling capacity assessment of animal manure was analyzed by comparing between the cultivated areas of crops and the amount of manure units that are generated from livestock manure. From this assessment, the possibility of recycling resources of livestock manure was evaluated. The amount generated of livestock manure in Gyeonggi-do were evaluated by applying the manure units to the number of livestock manure. The analysis of manure unit per ha shows that the N loading by MU is quite different by region. When it comes to nitrogen loading, the MU per ha of cultivated land in excess of the N-amount was the highest in the Gyeonggi-do province with 2.70 MU/ha, which is higher than the appropriate level. The Chungcheongnam-do province came next with 2.31 MU. So the recycling capacity assessment was carried out mainly based on areas of forage crops, rice that can be provided by recycling livestock manure. The recycling capacity ware highest in Jeollanam-do and Jeollabuk-do. In order to properly apply the livestock manure into organic resources, the seasonal situation that effects the nitrogen demands of crops along with the regional effects crop cultivation should be seriously analyzed. In addition, a system that can effectively produce and manage fertilizer should be established.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.485-496
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• 2013

In recent years, frequent terror or military attacks by explosion or impact accidents have occurred. Examplary case of these attacks were World Trade Center collapse and US Department of Defense Pentagon attack on Sept. 11 of 2001. These attacks of the civil infrastructure have induced numerous casualties and property damage, which raised public concerns and anxiety of potential terrorist attacks. However, a existing design procedure for civil infrastructures do not consider a protective design for extreme loading scenario. Also, the extreme loading researches of prestressed concrete (PSC) member, which widely used for nuclear containment vessel, gas tank, bridges, and tunnel, are insufficient due to experimental limitations of loading characteristics. To protect concrete structures against extreme loading such as explosion and impact with high strain rate, understanding of the effect, characteristic, and propagation mechanism of extreme loadings on structures is needed. Therefore, in this paper, to evaluate the impact resistance capacity and its protective performance of bi-directional unbonded prestressed concrete member, impact tests were carried out on $1400mm{\times}1000mm{\times}300mm$ for reinforced concrete (RC), prestressed concrete without rebar (PS), prestressed concrete with rebar (PSR, general PSC) specimens. According to test site conditions, impact tests were performed with 14 kN impactor with drop height of 10 m, 5 m, 4 m for preliminary tests and 3.5 m for main tests. Also, in this study, the procedure, layout, and measurement system of impact tests were established. The impact resistance capacity was measured using crack patterns, damage rates, measuring value such as displacement, acceleration, and residual structural strength. The results can be used as basic research references for related research areas, which include protective design and impact numerical simulation under impact loading.