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        검색결과 18

        1.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study is to develop the innovative application methodology of Geofoam for sustainable design of eco-bridges under deep soil cover. Traditionally, the soft maerial zone has been located on the top or above the buried conduit to reduce the earth pressures, which is called imperfect trench installation (ITI). There, however have been no previous studies for the application of ITI on buried arch structures. This study investigated the structural effects of Geofoam surrouding buried arch bridges, which was named as embedded trench installation (ETI). Various shapes and locations of Geofoam have been investigated for both ETI and ITI. The findings from this study showed that ETI could effectively increase the stability and sustainability of deeply buried eco-bridges.
        4,000원
        2.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Seasonal emission characteristics of odors and methane were investigated throughout the period of 17 months in which the emission status of odors and methane from soil cover layers in a sanitary landfill was measured. Complex odor emitted from soil cover layers fluctuated largely at the range of 7~20,800 OU (Odor Unit) in odor dilution ratio, and the median and average values were 2,080 and 4,203 OU, respectively. The intensity of complex odor showed higher values in the spring (5,663 ± 4,033 OU) and winter (6,056 ± 8,372 OU) than in the summer (1,698 ± 3,676 OU) and fall (1,761 ± 451 OU). Based on average concentrations, the compounds with high contribution values for the sum of the odor quotient (SOQ) were hydrogen sulfide (46.1%), methyl mercaptan (26.4%), and dimethyl sulfide (16.8%). This result shows that sulfur compounds were the main odor-causing compounds in the target landfill. The flux of complex odor was 0.17~70.36 OU·m−2·min−1 (Median 0.47, Average 5.40), and the flux of hydrogen sulfide was 0~114.70 μg·m−2·min−1 (Median 0.13, Average 5.91). The methane flux was 0.59~312.70 mg-CH4·m−2·min−1 (Median 25.61, Average 47.99). The methane concentrations emitted at the soil cover layers showed the highest values of 1.0~62.5% (Median 33.0, Average 21.1) in the spring, and the lowest values of 0.1~11.7% (Median 2.3, Average 3.7) in the winter. The methane concentrations in the summer and fall were similar with the average of 17.9% (range of 0.2-44.2%) and 12.5% (range of 2.2-42.5%), respectively. The emission data of odors and methane from soil cover layers can be utilized to establish management policy and apply mitigation technologies for the control of odor and greenhouse gases emitted in landfills.
        4,600원
        4.
        1998.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        No-tillage silage corn with legume hairy vetch(Vicia villosa Roth, HV) has renewed interest in supply of mineral N, soil erosion control at sloping land and weed control by cover of HV killed. This study was conducted to monitor concentration of soil mine
        4,000원
        5.
        2021.12 KCI 등재 서비스 종료(열람 제한)
        Our research work aimed to evaluate cover crop effects of winter rye on soil characteristics, soil conservation, and yield productivities on potato fields with 15% slope during a fallowed period. There were two controls of bared field without any cultivation and conventional potato cultivation without winter rye. Potato cultivation increased soil pH, organic matter, available phosphate, and exchangeable cation regardless of cover crop cultivation. Sub-soil, particularly, all components of soil chemical properties showed higher value in winter rye cultivation than conventional cultivation. Higher soil density was observed on cover crop cultivation than conventional cultivation resulting from root residues of the cover crop both topsoil and subsoil. Cover crop residues positively affected plant growth and reduced the amount of soil erosion by holding the soil. Although severe soil erosion was seen in conventional cultivation, winter rye cultivation declined soil erosion by 47% during the fallow period on potato slope fields. Distinct soil bacterial communities were detected among treatments and some OTU(Operational Taxonomic Unit)s showed significantly higher abundance in winter rye treatment. Total yield and commercial rate demonstrated no significant differences while higher tuber phosphate, K+, and Mg2+ contents were observed in winter rye cultivation.
        6.
        2018.05 KCI 등재 서비스 종료(열람 제한)
        Vertical farming systems offer many advantages in urban spaces. They have also been proposed as an engineering solution to increase the productivity per unit area of cultivated land by extending crop production in the vertical dimension. However, soil water retention is a major constraint affecting the plant environment. This study analyzed the effects of growth environment of Tropaeolum majus and Fragaria spp., on the vertical farming system, by using four different types of cover material types including sphagnum moss (Control), a shading net (S.N.), multi-layered fabric (M.L.F.), and non-woven fabric (N.W.F.). The volumetric soil moisture contents and plant characteristics were investigated from May to September 2014. Plant materials were individually cultivated in hanging baskets measuring 30×17×17 cm, filled with a mixture of soil and perlite, and placed at 1.5m height. Each treatment was performed in quadruplicate and consisted of five plants, amounting to a total of 20 plants. The analysis indicated that different covers were associated with multiple functions and soil water retention improvements may have a positive impact on the vertical farming system. The difference in soil water retention increased in the following order: M.L.F. > Control > N.W.F. > S.N.. Furthermore, the differences in plant height and survival rate increased in the following order: M.L.F. > Control > N.W.F. > S.N. Therefore, M.L.F yielded satisfactory good response for the vertical farming system of cover materials. Our results clearly demonstrate that vertical spaces represent an attractive alternative to urban farming and suggest that further increases in yield may be achieved via different cover materials in vertical farming using hanging baskets.
        9.
        2014.09 KCI 등재 서비스 종료(열람 제한)
        ‘부유’ 단감과수원에 적합한 녹비작물을 선발하기 위하여 헤어리베치, 레드클로버, 호밀, 헤어리베치+호밀을 파종하여 토양화학성과 물리성 그리고 과실수량과 품질을 조사하였다. 천근성인 레드클로버는 생육이 저조하여 피복도가 약 66%로 처리구에서 가장 낮았고 호밀 또는 헤어리베치+호밀 혼파처리구의 토양환원량이 가장 높았다. 식물체에서 환원되는 질소, 인산, 칼리 함량이 헤어리베치+호밀처리구 혼파처리구에서 가장 높아 토양의 유기물과 pH, 인산, 칼리, 칼슘과 전기전도도가 증가하였다. 토양의 용적밀도와 고상이 호밀 또는 헤어리베치+호밀처리구에서 감소되어 기상의 증가로 인한 공극률이 증가되었다. 헤어리베치+호밀처리에서 과실의 착과수와 수량이 가장 높았으며, 과실의 당도와 착색이 증가되는 효과가 인정되어 녹비작물로서 단감과원에 이용될 수 있을 것으로 판단된다.
        10.
        2013.10 서비스 종료(열람 제한)
        In this study, a full-scale test was conducted to analyze the behavior characteristics which are related to roadbed according to steel pipe press-in excavation during construction of underground railway crossing. the value of depth of soil cover that is the most sensitive element gets to increase gradually by 1.0, 1.5, and 2.0(H/D). Then we performed press-in excavation and measured the displacements of roadbed with LVDT. When the depth of soil cover level is 1.0(H/D), the maximum value of 5.2mm were seen at the point of 2mm for pipe press. Also, when depth of soil cover had increased, Uplift decreased more than 3 times in comparison with the one.
        11.
        2013.10 서비스 종료(열람 제한)
        Damage of pavement over corrugated steel plate culvert with shallow cover was analyzed by filed investigation and numerical analysis. Field measurement showed that the flexible culvert was within the deformation limit and was structurally stable. Numerical analysis showed that deformation of culvert at the crest during the passage of heavy vehicle was about 2.72mm while the thrust and moment within the structure was far below the allowable value. It is concluded that the pavement was damaged by the cyclic deformation of culvert by the heavy vehicle.
        12.
        2012.09 KCI 등재 서비스 종료(열람 제한)
        1. 각 시험구에서 재배 2년째 시기별 에너지작물의 초장을 조사한 결과, 하수슬러지 고화물을 처리한 시험구에서의 에너지작물 중 거대 1호의 생육이 가장 우수하였으며 원지반토에서는 생육이 미비하였다. 2. 원지반토의 거대 1호 초장은 재배 1년차 97 cm에서 2년차 229 cm로 141% 증가하여 성장폭이 하수슬러지 고화물을 처리한 두 시험구의 거대 1호에 비해 우수하였다. 3. 각 시험구의 토양 pH는 하수슬러지 고화물을 처리한 후 2년이 경과하여도 일정하게 pH 7.2~8.4의 수준을 유지하고 있었다. 원지반토의 염농도는 하수슬러지 고화물을 처리한 두 시험구에 비해 월등히 높은 것으로 나타났으며 원지반토의 평균 염농도(0.27%)는 1년차의 염분 농도(0.31%)와 비교하여 조금 감소한 것으로 나타났다. 4. 원지반토의 평균 치환성 나트륨(Ex. Na) 함량은 8.99 cmol+kg1으로 하수슬러지 고화물 혼합구의 평균치(0.7 cmol+kg1)에 비해 약 12배 높았으며, 하수슬러지 고화물을 처리한 두 시험구에 비해 월등히 높았다. 5. 하수슬러지 고화물 처리 후 에너지작물 재배 1년차와 2년차 동일시기(5월, 11월)의 토양 유기물 함량은 1년차에 비해 2년차 증가하였음을 알 수 있었고, 특히 하수슬러지 고화물 복토구의 유기물 함량의 증가폭이 가장 우수하였다. 6. 간척지 토양에 하수슬러지 고화물 처리는 토양 무기양분의 공급, 염류의 상향이동 완충 효과, 작토층 및 근권확대로 인한 지하경의 정상적인 번식이 이루어져 원지반토에 비해 에너지작물 생육이 우수하여 하수슬러지 고화물처리는 토양복토재로써 간척지 토양의 화학성 및 물리성 개선에 효과적이었음이 확인되었다.
        14.
        2007.11 KCI 등재 서비스 종료(열람 제한)
        Environment-friendly soybean planting system has been being required in the upland field with high slope and heavy rain in summer season. Changes of weed amount and soybean yield by rye cover crop and conservation tillage were investigated. Soil-disturbing at conservation tillage before soybean planting increased numbers and dry weights of weeds germinated in late spring such as Echinochloa crusgalli P. Beauv (barnyardgrass) and Portulaca oleracea L. (common purslane) regardless of herbicide spray even though the weed, Chenopodium ficifolium Smith germinated before soil-disturbing were higher at non-disturbing soil. Higher weed amounts at plots of strip-tillage (30cm rototilling) compared to minimum tillage (10cm rototilling) was mainly due to the weed increase by soil-disturbing. Soybean yields at plots with rye cover crop, particularly early maturity rye cover crop, were lower than those at plots without rye cover crop, which was due to lower soybean seedling stand by heavy rye residue. More researches are required for the higher soybean yield at the minimum tillage with rye cover crop in which weed amounts were low.
        18.
        1996.04 KCI 등재 서비스 종료(열람 제한)
        Observational date is integral in our understanding of present climate, its natural variability and any change due to anthropogenic effects. This study incorporates a brief overview of sampling requirements using data from the first ISLSCP Field Experiment (FIFE) in 1987 which was a multidisciplinary field experiment over a 15 km grid in Konza Prairie, USA. Sampling strategies were designed for precipitation and soil moisture measurements and also detecting land cover type. It was concludes that up to 8 raingages would be needed for valuable precipitation measurements covering the whole FIFE catchment, but only one soil moisture station. Results show that as new gages or station are added to the catchment then the sampling error is reduced, but the improvement in error performance is less as the number of gages or stations increases. Sampling from remotely sensed instruments shows different results. It can be seen that the sampling error at larger resolution sizes are small due to competing error contribution from both commission and omission error.