• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.431-437
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• 1998

This study was performed to ascertain the three-dimensional effect of the crack reduction and the restrained effect of crack growth, and to yield a suitable mixing ratio of the synthetic fiber reinforced soil. The results of the study are as follows ; 1) The synthetic fiber has the resisting force for crack because of the adhesion due to the attraction of soil particles. 2) As the synthetic fiber length and the mixing ratio are increased, mono filament synthetic fiber reinforced soil is increased the effects of crack reduction and the restraint of crack growth. 3) The fibrillated synthetic fiber is more effective than mono filament synthetic fiber for crack. 4) A suitable mixing ratio of synthetic fiber reinforced soil is 0.5% of the fibrillated synthetic fiber.

• 한국농공학회지
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• 제41권3호
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• pp.59-65
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• 1999

This study has been performed to confirm the three dimensional effect of the crack reduction and the restrained effect of crack growth for the synthetic fiber reinforced soil. Two types of polyrpropylene fiber and low plastic clay(CL) were used for the test. And the test variable were fiber length and so on. The results of the study were summarized as follows ; 1) The mixing of synthetic fiber was effective in reducing crack growth due to adhesion between soil partlcles and synthetic fiber.l Especially initlal crack was delayed, as compared with the pure soil, for about 1 day in case of mono filament synthetic fiber and for about 1 or 2 days in case of fibrillated syntetic fiber. 2) As the content and length of synthetic fiber were increased , the effect of crack reduction was increased. It was found that 0.5% fibrillated synthetic fiber with 40mm length reinforced soil had about 3 times more effective than natural soils. 3) In case of the same fiber content and fiber length, the fibrillated synthetic fiber has nmore effective than the mono filament synthetic fiber for crack reduction.

• 한국환경과학회지
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• 제22권7호
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• pp.801-810
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• 2013

To improve the physical and chemical properties of the soil and increasing water-retaining property of the soil, Superabsorbent synthetic polymeric materials have been used. The experiment carried out from April to July 2012 after the influence evaluation of Superabsorbent synthetic polymeric materials to vines plant. The result shows that the study of Hedera japonica Tobler, the growth and the survival rates rank as media > hydroponic > superabsorbent synthetic polymers, and the growth and the survival rates are considerably pessimistic in the experiment of hydroponic and superabsorbent synthetic polymers. In the study of Trachelospermum asiaticum var. intermedium, the growth and the survival rates rank as hydroponic > media > superabsorbent synthetic polymers, the difference between the experiment of hydroponic and is very small and the survival rates are not very good in the experiment of superabsorbent synthetic polymers. In the study of Euonymus fortunei var. radicans Rehder,it is insignificantly difference among the different of planting based. Judging from these results, the differences are depending on the species of plants. The thesis holds that the characteristics of plant should be considered in plant cultivation and soil improvement in the future, and it is desirable to use the appropriate mixing ratio of soil in soil improvement as well.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.582-587
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• 1999

This study has been done to investigate the characteristics of synthetic fiber reinforcement sol with fully satruated . To this end, consolidated undrained triaxial test was performed on synthetic fiber reinforcement soil using the soft clay and plypropylene fiber . From the results of test, it was formed that the mixing ratio for weight and the aspect ratio of synthetic fiber have an effect on the shear characteristic of synthetic fiber rinforcement soil. Especially shear paramter C has line relationship for mixing ratio of fiber, and øhas parabolic relationship for mixing ratio of fiber.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.1-25
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• 2003

geosynthetles -A manufacturerl synthetic product used with soil, rock or other materials to enhance the performance of geotechnical works geotentiles - A permeable textile product used in contact with a soil for separation, filtration, reinforcement and drainage geemembranes - A synthetic low permeability material used as liner in geotechnical applications. (omitted)

• 한국농공학회논문집
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• 제60권1호
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• pp.21-30
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• 2018

In this study, we developed the Soil Moisture Data Assimilation (SMDA) scheme to extract Effective Soil Characteristics-ESC (Sand, Silt, Clay %) from MODerate resolution Imaging Spectroradiometer (MODIS) products. The SMDA scheme was applied to the MODIS-based Soil Moisture (SM) data during the summer (July to September) period. Then the ESC and soil erosion factors (K) were predicted, respectively. Several numerical experiments were conducted to test the performance of SMDA at the study sites under the synthetic and field validation conditions. In the synthetic experiment, the estimated soil moistures values(R: >0.990 and RMSE: <0.005) were identified well with the synthetic observations. The field validation results at the Bangdongri and Chungmicheon sites were also comparable to the TDR-based measurements with the statistics (R: 0.772/0.000 and RMSE: 0.065/0.000). The estimated ESC values were also matched well with the measurements for the synthetic and field validation conditions. Then we tested the SMDA scheme to extract the ESC from the MODIS-based soil moisture products. Although uncertainties exist in the results, the estimated soil moisture and ESC based on the SMDA were comparable to the measurements. Overall, the K factors were similarly distributed based on the derived ESC. Also, the K factors in the mountainous regions were higher than those of the relatively flat areas. Thus, the newly developed SMDA scheme can be useful to estimate spatially and temporally-distributed soil erosion and establish soil erosion management plans.

• 한국환경농학회지
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• 제11권2호
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• pp.125-132
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• 1992

토양 및 수용액조건에서와 자외선조사시의 bifenthrin의 주 분해대사산물을 확인하고 토양중 에서의 용탈을 조사한 결과는 다음과 같다. 토양 및 수용액조건에서와 자외선조사시 bifenthrin의 일차분해산물은 2-methylbiphenyl-3-ylmethanol로 HPLC, UV, Mass 및 NMR로 확인되었으며 bifenthrin의 주 분해경로는 ester결합의 가수분해 작용으로 나타났다. 자외선 조사시 bifenthrin은 첨가농도 10,100ppm에서 24시간만에 거의 분해 소실되었으며 1,000ppm일 때는 약 80%정도 분해되었다. Soil TLC 및 column상에서 bifenthrin은 거의 용탈되지 않고 표토에 존재하였다.

• Structural Engineering and Mechanics
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• 제68권2호
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• pp.159-170
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• 2018

This paper aims to develop response modification factors for stiffness degrading structures by incorporating soil-structure interaction effects. A comprehensive parametric study is conducted to investigate the effects of key SSI parameters, natural period of vibration, ductility demand and hysteretic behavior on the response modification factor of soil-structure systems. The nonlinear dynamic response of 6300 soil-structure systems are studied under two ensembles of accelograms including 20 recorded and 7 synthetic ground motions. It is concluded that neglecting the stiffness degradation of structures can results in up to 22% underestimation of inelastic strength demands in soil-structure systems, leading to an unexpected high level of ductility demand in the structures located on soft soil. Nonlinear regression analyses are then performed to derive a simplified expression for estimating ductility-dependent response modification factors for stiffness degrading soil-structure systems. The adequacy of the proposed expression is investigated through sensitivity analyses on nonlinear soil-structure systems under seven synthetic spectrum compatible earthquake ground motions. A good agreement is observed between the results of the predicted and the target ductility demands, demonstrating the adequacy of the expression proposed in this study to estimate the inelastic demands of SSI systems with stiffness degrading structures. It is observed that the maximum differences between the target and average target ductility demands was 15%, which is considered acceptable for practical design purposes.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권4호
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• pp.28-34
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• 2020

Nitrate released from chemical fertilizer, animal wastes, and synthetic detergents can cause methemoglobinemia to infants, thus the standard in drinking water is set to 10 mg/L as World Health Organization recommended. In this study, zero-valent iron-modified rice straw biochar was used to reduce and remove nitrate in the aqueous phase. The rice straw biochar was prepared by pyrolyzing the biomass at 700℃ for 3 hours, and the biochar was modified using 1 M Fe(III), and the Fe(III) on the biochar was reduced to zero-valent iron using sodium borohydride. The modified biochar removed nitrate effectively, which removed more than 91% of nitrate. For the synthetic groundwater, the nitrate removal was lowered to 82% due to the presence of other anions.

• 한국토양비료학회지
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• 제25권4호
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• pp.311-324
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• 1992

Polymeric substances in organic matter of soils aggregate soil particles into a crumb structure which greatly influences such properties as water movement, aeration and heat transfer. Poorly-structured soils may be improved by the incorporation of synthetic polymers where the main objects are : promoting germination or establishing crops, improving drainage, combating wind and water erosion, and reducing evaporation from the surface of soil under arid condition.