• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.183-192
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• 2005

Natural ventilation in radioactive waste repositories is considered to be less efficient than mechanically forced ventilation for the repository working environment and hygiene & safety of the public at large, for example, controlling the exposure of airborne radioactive particulate matter. It is, however, considered to play an important role and may be fairly efficient for maintaining environmental conditions of the repository over the duration of its lifetime, for example, moisture content and radon (Rn) gas elimination in repository. This paper describes the feasibility of using natural ventilation which can be generated in the repository itself, depending on the conditions of the natural environment during the periods of repository construction and operation. Evidences from natural cave analogues, actual measurements of natural ventilation pressures in mountain traffic tunnels with vertical shafts, and calculations of airflow rates with given natural ventilation pressures indicate possible benefits from passive ventilation for the prospective Korean radioactive waste repository. Natural ventilation may provide engineers with a cost-efficient method for heat and moisture transfer, and radon (Rn) gas elimination in a radioactive waste repository. The overall thermal performance of the repository may be improved. The dry-out period may be extended, and the seepage flux likely would be decreased.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.5
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• pp.1-8
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• 2013

In order to evaluate 2 extensive green roof systems(Sedum Box Roof System and Roof-rainwater Utilization System) for urban greening and select ground-cover plants, which can adapt well to the drought tolerance in an extensive green roof system on 12 species. This study was carried out in order to suggest an experimental base in assessment of the Green Roof-rainwater Utilization System and selecting the drought resistance of plants. Adopting the natural drought method, this paper studies the drought resistance of 12 kinds of ground cover plants. The drought-resistance of ground cover plants subjected to dry processing time were evaluated using relative water content on leaves, relative electric conductivity and chlorophyll content in 12 kinds of plants, and the relation between soil water content under drought stress. Drought resistance of the plants were subject to rooftop drought resistance treatments. The result showed that with the increase of stress time, the relative water content and chlorophyll content on leaves were in a downward trend while the relative electric conductivity was in an upward trend. Among the 12 species of ground cover plants, excluding Pulsatilla koreana, Ainsliaea acerifolia was selected for rooftop plants because they showed resistance to drought strongly and took adaptive ability. These results showed that drought tolerance of plants in Roof-rainwater Utilization System were stronger than the Sedum Box Roof System. Therefore, the Roof-rainwater Utilization System is good for plants. It helps them adapt well to the drought tolerance in rooftops and can be used for urban greening.

• Resources Recycling
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• v.9 no.1
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• pp.36-43
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• 2000

This study was carried out for treatment and reuse of inorganic sludge from Fenton process at B dyeing wastewater treatment plant. The parameters for pilot-scale treatment system were derived from the results of this study. It was found that $COD_{cl}$ of the treated effluent became lower than 100 mg/l approximately on the optimal reaction condition. 2nd sludge which was generated after redissolving sludge was analyzed, and it showed that reduction ratio of ash in 2nd sludge and total dry sludge weight in comparison with current sludge were 85% and 65%. Also Fe salt in sludge was redissolved about 90~95% of initial Fe by weight. It was estimated almost ￦350,000,000 for sludge reuse process. It was estimated saving of about ￦1,300,000 per day (￦420,000,000 per year) in operating cost based on 30,000 $m^3$/d treatment, which these were about ￦430,000 per day in chemical, ￦1,100,000 per day in sludge transportation and ￦200,000 per day in equipment maintenance. Payback period with interest charge for investment cost was estimated about 10.5 months. Also, net present value (NPV) was ￦792,000,000 and internal rat of return (IRR) was about 110%.

• Journal of Korean Society of Rural Planning
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• v.15 no.2
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• pp.81-96
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• 2009

This study has found out the status of the environment ecology(topography structure. land-use, flora, plant community structure, wildbird) in 10 uninhabited islands(i.e. Kei island, Hadon island, Sangdon island, Daewa island, Hwanggang island, Naebi island, Oebi island, Prickly castor-oil tree island, Tongin island, Yuk island), Namhae-gun, Gyeongsangnam-do. Moreover, It has suggested ways of improving the environment ecology status by classifying the type of environment ecology about the degree of use and damage that based on the results of environment ecology survey. According to the results of topography structure survey, the survey site altitude was ranged within 1m$\sim$25m, otherwise, the radient was classified the rock area(.i.e. slope of less than $5^{\circ}$ the dead level) and the slope area where is steep slope. Moreover, there was showed evenly a variety of aspect. Land-use were divided the field(Kei island), dry native grasslands(Hadon island), naturalized grasslands(Sangdon island), Pinus thunbergii community(Dacwa island, Hwanggang island, Naebi island, Yuk island), the rock area(Oebi island, Prickly castor-oil tree island, Tongin island). As the results of flora survey, the number of plant species were 30$\sim$115 species and the naturalized species were found 2$\sim$12 species in each site. The results of plant community structure analysis, The dominant species were Pinus thunbergii and Pinus densiflora were in upper tree layer, furthermore, it were Pinus thunbergii, Eurya japonica, Prunus sargentii, Celtis sinensis, Morus bombycis, ect. in cannopy tree layer. In shrub layer, the dominant species were Rosa multiflora, Rubus crataegifolius, Parthenocissus tricuspidata, etc. The status of wildbird bird, had been found 42 species 938 individuals, especially, there were Bubo bubo kiautschensis(natural monument No. 324) and Haematopus ostralegus osculans(natural monument No. 326). According to these synthetic results, we are able to classify the 5 types of environment ecology such as the natural coast forest that composed of Pinus thunbergii and Pinus densiflora(Daewa island, Hwanggang island, Naebi island, Oebi island, Tongin island, Yuk island), the field in vegetation area(Kei island), vegetation succession area of fallow field type(Hadon island), vegetation damage area by the forest fire and disturbance elements(Prickly castor-oil tree island), dominant naturalized species grassland by grazing cattle(Sangdon island).

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.247-257
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• 2018

This study was conducted to find out the optimum silicate fertilization for improving the quality and density of zoysiagrass (Zoysia japonica Steud.), the growth of zoysiagrass and changes in chemical properties of soil in field experiments treated with different levels of silicate fertilizer during 3 years from 2012 to 2014. An increase in the silicate fertilizer from 100, 200, to $400kg\;10a^{-1}$ led to a significant increase in the fresh and dry weight of shoots and stolons, the number of shoots and length of stolon, but were not significantly different between 200 and $400kg\;10a^{-1}$. Moreover, soil pH, EC and the contents of available $SiO_2$ were increased as the rate of silicate fertilizer application increased. Thus, these results demonstrated that the silicate fertilizer rate for maximum growth of zoysiagrass was $200kg\;10a^{-1}$ in consideration of improving growth of zoysiagrass and the chemical property of the soil.

• Journal of the Korean Society of School Health
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• v.16 no.1
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• pp.1-8
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• 2003

Purpose : While there have been growing concerns about the effects of Asian dusts on health, there are few studies for relationship between Asian dusts and health outcome. This study was designed to examine the perceived symptoms and behavior change of children during the Asian Dust events. Methods : We surveyed 459 students at an elementary school in Seoul, Korea from November 20th to 27th 2002. Children with parents were asked to return the completed questionnaires within a week. The questionnaires included the sociodemographic factor, previous respiratory disease, and perceived symptom, hospital visits and behavior change during the Asian dusts. Results : The majority of children reported that they restrained going out and outdoor recreational activity during the Asian dusts. The rate of children who worn the mask was 49% and 47% in second grade and fifth grade, respectively. Regarding the perceived symptom during the Asian dusts, the children in 2nd were more likely to have symptom than 5th and there were significant difference between two groups in cough, asthma symptom, dry cough, phlegm and medication for allergy or asthma symptom. In addition, children who had previous disease were more likely to change behavior in order to prevent the effects of Asian dusts. Conclusions : This study suggested that the younger children and children who had past respiratory disease were susceptible to the effect of Asian dusts. There is a need for providing public information and health education to prevent the impact of Asian dusts on health.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.165-172
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• 2001

Owing to raising number of livestock, we have a problem to solve disposal of livestock manure. We know that soil have the digestion ability of livestock manure as one of multifunctionality. I carried out to investigate of livestock manure digestion (especially pig and chicken manure) that is considered as nitrogen fertilizer in upland crops. The results were summarized as follows: 1. The amount of pig manure was(1999) 4,592,375 tons/year, and chicken manure was 4,488,166 tons/year and equivalent to 41,912 tons N/year and 76,223 tons N/year, respectively. 2. The definition of the digestion ability of livestock manure is as the maximum application amount of livestock manure without injuring soil and plant. And the calculation model of digestion ability of livestock manure(ALMD) is follows: ALMD = amount of nitrogen requirement per each upland crop / {(total nitrogen contents in livestock manure) ${\times}$ (nitrogen fertilizer efficiency of livestock manure)} 3. The amount of ability of pig and chicken manure for upland crops (dry based) were 1,142.9kg/10a and 540.1kg/10a, respectively. 4. The order of amount of digestion ability of livestock manure on upland were vegetables > orchards > miscellaneous grains(corn) > barley > potatoes > pulses > oil seeds & special crops ) fodder crops) mulberry.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.271-276
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• 1998

This experiment was carried out to investigate the changes on nutrient uptake and yields of onion when it was applied with urea and ammonium sulfate as nitrogen fertilizer types; potassium chloride and potasssium sulfate as potassium fertilizer types and lime requirement and phosphorus absorption coefficient controlled 5% as soil improvement index. The variety of onion used was CheonJuHwang and the soil used was Yonggye series in the Jeonnam Muan area. The amounts of N, P and K uptake were higher in the mixed application plot of ammonium sulfate and potassium sulfate than in the plot of urea or potassium chloride. The sulfate content of soil was higher in the period of plant growth than in the harvest stage. The sulfate content of plant was highest in the harvest stage and this content was higher in the stem and in the leaf than in the bulb. The sugar content of onion was 7.43~8.23 Brix content was higher in the large bulb than in the small bulb. The weight of dry matter and the rate of good quality were high in the mixed application plot of ammonium sulfate and potassium sulfate, so the yield of onion was increased 2~6% compared with control.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.1
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• pp.31-36
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• 1993

A pot experiment was carried out to investigate the influence of application of nitrogen, phosphorus and calcium on the yield and uptake of Sr-90 by soybean plant. The results obtained were summarized as follows : 1. The application of N tended to decrease the dry matter yield of soybean. There was, however, difference in the effect on the yield between $NH_4-N$ and $NO_3-N$ ; the yield was higher in the former in the latter. On the other hand, the application of P and Ca increased the yield. 2. The uptake of Sr was decreased by the application of N, but such effect was greater in $NH_4-N$ than in $NO_3-N$. 3. The effect of N application in reducing the uptake of Sr. was enhanced by the application of P with N. 4. The combined application of P and lime showed significant effect of reducing the uptake of Sr by soybean plant. The uptake of Sr was lowest in the pot that received P, lime and $NH_4-N$ together.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.176-180
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• 2011

Rice production depended on the weed control. The purpose of this study was conducted to evaluate the influence of tillage with chemical amendments + 5 cm flooded, no-tillage without Chinese milk vetch + 5 cm flooded (NTNT 5 cm), no-tillage amended with Chinese milk vetch + 5 cm flooded (NTCM 5 cm), and no-tillage amended with Chinese milk vetch + 10 cm flooded (NTCM 10 cm) on weed occurrence and yield of rice in paddy. Triplicate experimental plots were laid out in a randomized complete block design and compared by employing least significant difference. The dry weights of weeds in NTCM 5 cm and NTCM 10 cm were 11% and 4% level of NTNT 5 cm (p<0.05) and were 3.2 times and 1.2 times more than in conventional tillage system. In addition, the Aneilema keisak and Ludwigia prostrata were significantly increased in NTNT 5 cm (p<0.05). The yield of rice grain in NTCM 10 cm was 2.6 times more than in NTNT 5 cm and was 89% level of conventional tillage system. Our findings suggest that NTCM 10 cm should be enhance of weed control as well as improving of yield of rice in paddy.