• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.219-222
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• 2003

Bech scale tests were performed to evaluate the adaptability of industrial wastes, especially bottom ash, salg and phosphogypsum among others, for constructing the surface layer of a landfill or reclamation, which function is a vegetation base layer. In the test, columes test were used to check the extraction characteristics of wastes and small PVC soil-box that equipped the drainage device was used to model a performance of layers and to monitor the growth of plants at the composite layer of those. Tests have been continued during one and half year and It has been verified that bottom ash and phosphogypsum look like as a valuable material to safely reuse as the vegetation base layer even though some unconfined factors are remain.

• Journal of Forest and Environmental Science
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• v.31 no.2
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• pp.109-118
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• 2015

Allelopathy is an ecological phenomenon that refers to the beneficial or harmful effects of one plant on another plant, both crop and weed species, by the release of organic chemicals (allelochemicals) from plant parts by leaching, root exudation, volatilization, residue decomposition in soil and other processes in both natural and agricultural systems. Allelopathy can affect many aspects of plant ecology including occurrence, growth, plant succession, the structure of plant communities, survival, dominance, diversity, and plant productivity. In this review, we describe the concept of allelopathy, some mechanisms of operation within plants and then focus on a select number of gymnospermous tree genera: Ephedra, Pinus, Taxus, Cedrus, Juniperus, Picea, Cunninghamia and Araucaria. Pinus, Taxus (yew) and Cedrus (cedar) trees have a strong negative allelopathic effect on the germination, growth, or development of other plant species in the forest community.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.551-558
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• 2001

The horizontal drain method is one of methods improving reclamation ground. This method reduces consolidation time by using drained installed horizontally, and negative pressure is applied on end of these drains by vacuum pump. But, effective negative pressure still wasn't evaluated in applying this method to reclamation ground. To estimate optimum negative pressure, soil box test that make a model the in-situ by installing horizontal drains in the center is performed pressing different vacuum pressure In the laboratory, and the variations in settlement and volume of drained water through the drains during consolidation process were measured. Also, water content with distance from drain and with depth is measured after the test.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.789-799
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• 2019

The settlement hardly occurs in structures supported by pile foundation such as abutment, culvert but a cavity is formed in the lower part of a structure. As a result, soil discharged from the lateral ground to the cavity accelerates the settlement of the lateral ground of the structure, resulting in a larger settlement. Therefore, in order to prevent problems caused by cavity under the structure supported by pile foundation, soil Flow Protector (briefly called 'FLP'), which can be easily installed on the side of structure, was developed. In this study, an laboratory model test was carried out to prove the reduction effect of settlement and to estimate the optimal installation length of the FLP. As a result, the installation of the FLP reduced the settlement of the lateral ground and prevented the leakage of lateral ground soil into the cavity. If the stiffness of the FLP is small, the state or active earth pressure is generated in the upper part, which is not favorable for stability. But if the stiffness of the FLP is high enough, the passive earth pressure area is generated in the upper part, which will be advantageous for the stability. Also, the increased installation length of FLP is effective to reduce the settlement. And the ratio of the optimal length of the FLP to the box structure height (H = 250 mm) are flexible FLP 1.38, stiff FLP 0.73.

• Journal of the Korean Geosynthetics Society
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• v.8 no.1
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• pp.33-40
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• 2009

The laboratory tests and field plate load test were carried out to evaluate the reinforcement effect of geocell for road construction. The geocell-reinforced subgrade shows the increment of cohesion and friction angle with comparison of non-reinforced subgrade. In addition, the field plate load test was performed on the geocell-reinforced subgrade to estimate the bearing capacity of soil. The direct shear test was conducted with utilizing a large-scale shear box to evaluate the internal soil friction angle with geocell reinforcement. The number of cells in the geocell system is varied to investigate the effect of soil reinforcement. The theoretical bearing capacity of subgrade soil with and without geocell reinforcement was estimated by using the soil internal friction angle. The field plate load tests were also conducted to estimate the bearing capacity with geocell reinforcement. It is found out that the bearing capacity of geocell-reinforced subgrade gives 2 times higher value than that of unreinforced subgrade soil. The settlement and the distribution of deformation were also estimated by using the finite element method. The magnitude of settlements on the geocell-reinforced subgrade and unreinforced subgrade are 6.8cm and 1.2cm, respectively.

• Journal of the Korean Geotechnical Society
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• v.35 no.11
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• pp.63-74
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• 2019

Numerical liquefaction model and response history analysis procedure are verified based on dynamic centrifuge test results. The test was a part of the Liquefaction Experiments Analysis Project (LEAP). The model ground was formed inside of rigid box by using the submerged Ottawa F65 sand with a relative density of 55% and 5° of surface inclination. A tapered sinusoidal wave with a frequency of 1 Hz was applied to the base of the model box. Numerical analyses were performed by two dimensional finite difference method in prototype scale. The soil is modeled to show hysteretic behavior before shear failure, and Mohr-Coulomb model is applied for shear failure criterion. Byrne's liquefaction model was applied to track the changes in pore pressure due to cyclic loading after static equilibrium. In order to find an appropriate flow condition for the liquefaction analysis, numerical analyses were performed both in drained and undrained condition. The numerical analyses performed under the undrained condition showed good agreement with the centrifuge test results.

• Journal of the Korean Professional Engineers Association
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• v.19 no.1
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• pp.12-24
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• 1986

The number of visiters to Bukhan Mt. national park, generation quantity of solid waste and collection system were researched to consider a counterplan for the pollution control of the national park and study for developing the effective treatment of solid waste was tried through the proximate analysis of each component containing. Results obtained in this study were summerized as follows; The great part of visitors go on an excursion to the Bukhan Mt. national park during July and August and also, the solid waste was generated nearly a half of the total amount at the same period. The major collection facilities in the national park were waste basket and incineration box. But the incineration box was too large in volume and very far in distance, and its collection period was irregular, so it was cause to the congestion of solid waste and bad smell and dirty. Therefore, to complete collection of solid waste, we must set up the waste basket which able to find within 40～50m from the origination place of solid waste and induce the visitors to throw the solid waste. It was obtained as moisture content: 48.5 wt%, volatile solid: 28.4wt％, fixed solid: 23.1 wt％, lower heating value: 1,320kca1/kg from experimental analysis of solid waste. According to this analysis, the incineration operation is possible, but the generation quantity of solid waste was too small to construct incineration plant for heat recovery. It was found that it is suitable for the aerobic composting by mixing with the night soil which generate in the national park after the recovery of resources such as metals, glasses and plastics.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.125-139
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• 1999

It is difficult to evaluate the shear strength of weathered residual soils because of the difficulties of undisturbed sampling. In this study, a sampling device, direct shear box with shoe, was developed in order to get undisturbed samples easily for direct shear tests, and undisturbed samples could be successfully obtained. Through direct shear tests on undisturbed samples, the shear strength was evaluated with the variation of saturated conditions. In order to consider the effect of disturbance on the shear strength, a static compaction device was developed, and then it was found that undisturbed samples show greater shear strengths than the disturbed ones under natural water contents and similar strengths to the ones under soaked conditions. Further, the shear strength evaluated from direct shear tests was compared with the result of triaxial tests on undisturbed samples, and soaked strengths of the former were similar to the latter. As the result of stability analyses on an actual failed slope, it was found that the shear strength can be evaluated reasonably using direct shear box with shoe.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.318-321
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• 2002

To induce recombinant protein under phosphate restricted conditions such as soil, we have constructed the expression vector (pEAAP) with phoA gene promoter of Enterobacter aerogenes. To construct the pEAAP, deletion of the T7 promoter and lac operator from pET-22b(+) by BglII-XhoI digestion and addition of the phoA gene promoter (containing the pho box) were performed. To test pEAAP as an expression vector controled by phosphate limitation, pEAPHY1 was constructed with the phytate gene (Bsa-phy1) of Bacillus subtillis var. amyloliquefaciens (KCTC 8913P). Under the phosphate-limitation condition, CK-PHY1 ( Escherichia coli JM109 was transformed with pEAPHY1) expressed the 41 kD Bsa-Phy1 . Also CK-PHY1 formed the clear zone in solid medium containing phytate as a sole phosphate source.

• Food Science and Preservation
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• v.11 no.2
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• pp.282-285
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• 2004

This experiment was carried out to investigate the cost reduction of rhizome through the stable storage of Jiwhang #1(Rehmannia glutinosa Libosch). The growth characteristics of Jiwhang #1 are different from those of local Rehmannia glutinosa L. varieties in Korea. Various storage methods was introduced and analyzed for 120 days. Among storage methods, changes in mean daily temperature in storage location were the least from 7.2 to 13.8$^{\circ}C$ in underground storage, while those were wide in styrofoam box filled with soil, and changes in mean daily relative humidity were the highest 98.2% in underground storage. As the storage period increased, the rhizome brix and the rate of rhizome loss and spoiled rhizome increased. The brix and loss rate of rhizome were higher in net sack filled with hull and styrofoam box filled with hull, but the rate of spoiled rhizome was the greatest in underground storage among storage methods. As the storage period increased, the hardness of rhizome epidermis increased, while that of rhizome endodermis decreased.