• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.163-166
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• 2002

The concurrent injection of cosolvent and air, a cosolvent-air (CA) flood was recently suggested for a dense nonaqueous phase liquid (DNAPL) remediation technology. The objectives of this study were to elucidate the DNAPL removal mechanisms of the CA flood and to quantify mass transfer rate coefficients during CA flooding. DNAPL removal mechanisms were examined by evaluating the effects of air flow rate and DNAPL solubility and visually documented at a pore-scale. Two serial processes, immiscible displacement and dissolution, were experimentally and visually documented during CA flooding. Mass transfer rate coefficients (K) were computed from the data showing PCE saturation versus time. Results showed that CA floods exhibited higher K values than cosolvent floods without concurrent air injection. (This document has not been subjected to Agency review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred.)

• Journal of Soil and Groundwater Environment
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• v.18 no.4
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• pp.8-18
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• 2013

Biocarrier beads with dead biomass, Bacillus drentensis, immobilized in polymer polysulfone were synthesized to remove heavy metals from wastewater. To identify the sorption mechanisms and theoretical nature of underlying processes, a series of batch experiments were carried out and a mathematical model was developed to quantify the biosorption of Pb(II) by the biocarrier beads. A series of mass balance equations for representing mass transfer of metal sorbents in biocarrier beads and surrounding solution were established. Major model parameters such as external mass transfer coefficient and maximum sorption capacity, etc. were determined from pseudo-first-order kinetic models and Langmuir isotherm model based on kinetic and equilibrium experimental measurements. The model simulation displays reasonable representations of experimental data and implied that the proposed model can be applied to quantitative analysis on biosorption mechanisms by porous granular beads. The simulation results also confirms that the biosorption of heavy metal by the biocarrier beads largely depended on surface adsorption.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3596-3601
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• 2015

Enhancement of the existing program for analyzing a pile driven by vibro hammer was tried. Damping effect of dynamic soil resistance and clutch friction were added to the existing governing equation which constitute vibrating system of vibro hammer-pile-soil. Parameters of the modified Ramberg-Osgood model which simulates dynamic load transfer curves for the developed program were recomputed. Comparing the results of the modified program with those of the field tests, pile displacement with time and load transfer behavior were more similar to those of the field test. The penetration rates obtained from the modified program were more close to those of the field test rather than those of the commertical program.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.2
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• pp.62-73
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• 1997

The application of nutrients and pesticides to agricultural lands has been reported to contribute to groundwater contamination, which can be explained by preferential flow in lieu of convective-dispersive flow. An one-dimensional numerical model depicting preferential water and solute movement was modified to describe multi-layer flows. The model is based on a piecewise linear conductivity function. By combining conservation of mass and Darcy's law and using the method of characteristics a solution is obtained for water flow in which water moves at distinct velocities in different flow regions instead of an average velocity for the whole profile. The model allows transfer ofqr solutes between pore groups. The transfer is characterized by assuming mixing coefficients. The model was applied to undisturbed soil columns and an experiment site with structured sandy clay loam soil. Chloride, bromide, and 2, 4-D were used as tracers. Simulated solutes concentrations were in good agreement with the soil column data and field data in which preferential flow of solute is significant. The proposed model is capable of describing preferential solute transport under laboratory and field conditions.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.211-222
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• 2000

The design values of rock socketed pile related with properties of rock mass are not clearly established. However, the drilled shafts socketed in rock are widely used as the foundation of large scaled structure. In this study, the characteristics of behavior of rock socketed pile is researched, and the properties of interface between pile and rock considering soil-structure interaction are evaluated for numerical modeling of rock socketed pile based on the previous researches. Based on the properties of interface and rock mass, the behaviors of rock socketed piles are numerically modeled and compared with field measurement. To verify the numerical analysis, a micro pile socketed in rock is modeled and the results of numerical analysis are compared with field measurement. The numerical results show a good agreement with field measured data, especially in terms of load transfer characteristics.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.457-468
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• 2000

The design values of rock socketed pile related with properties of rock mass are not clearly established. However, the drilled shafts socketed in rock are widely used as the foundation of large scaled structure. In this study, the characteristics of behavior of rock socketed pile is researched, and the properties of interface between pile and rock considering soil-structure interaction are evaluated for numerical modeling of rock socketed pile based on the previous researches. Based on the properties of interface and rock mass, the behaviors of rock socketed piles are numerically modeled and compared with field measurement. To verify the numerical analysis, a micro pile socketed in rock is modeled and the results of numerical analysis are compared with field measurement. The numerical results show a good agreement with field measured data, especially in terms of load transfer characteristics.

• Geomechanics and Engineering
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• v.21 no.4
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• pp.379-390
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• 2020

The behavior of a piled raft system in multi-layered soil subjected to vertical loading has been studied numerically using 3D finite element analysis. Initially, the 3D finite element model has been validated by analytically simulating the field experiments conducted on vertically loaded instrumented piled raft. Subsequently, a comprehensive parametric study has been conducted to assess the performance of a combined piled raft system in terms of optimum pile spacing and settlement of raft and piles, in multi-layered soil stratum subjected to vertical loading. It has been found that a combined pile raft system can significantly reduce the total settlement as well as the differential settlement of the raft in comparison to the raft alone. Two different arrangements below the piled raft with the same pile numbers show a significant amount of increase of load transfer of piled raft system, which is in line with the load transfer mechanism of a piled raft. A methodology for the factor of safety assessment of a combined pile raft foundation has been presented to improve the performance of piled raft based on its serviceability requirements. The findings of this study could be used as guidelines for achieving economical design for combined piled raft systems.

• The Plant Pathology Journal
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• v.35 no.4
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• pp.362-371
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• 2019

Plant phenotype is affected by a community of associated microorganisms which requires dissection of the functional fraction. In this study, we aimed to culture the functionally active fraction of an upland soil microbiome, which can suppress tomato bacterial wilt. The microbiome fraction (MF) from the rhizosphere of Hawaii 7996 treated with an upland soil or forest soil MF was successively cultured in a designed modified M9 (MM9) medium partially mimicking the nutrient composition of tomato root exudates. Bacterial cells were harvested to amplify V3 and V4 regions of 16S rRNA gene for QIIME based sequence analysis and were also treated to Hawaii 7996 prior to Ralstonia solanacearum inoculation. The disease progress indicated that the upland MM9 $1^{st}$ transfer suppressed the bacterial wilt. Community analysis revealed that species richness was declined by successive cultivation of the MF. The upland MM9 $1^{st}$ transfer harbored population of phylum Proteobacteria (98.12%), Bacteriodetes (0.69%), Firmicutes (0.51%), Actinobacteria (0.08%), unidentified (0.54%), Cyanobacteria (0.01%), FBP (0.001%), OD1 (0.001%), Acidobacteria (0.005%). The family Enterobacteriaceae of Proteobacteria was the dominant member (86.76%) of the total population of which genus Enterobacter composed 86.76% making it a potential candidate to suppress bacterial wilt. The results suggest that this mixed culture approach is feasible to harvest microorganisms which may function as biocontrol agents.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.26-47
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• 2010

When the term conservation is used with regard to excavated features, it means not only conservation but also restoration. Restoring the features here does not imply restoring their original form but restoring their form at the moment of excavation. That means, the conservation of excavated features includes the concept of both reparation and restoration. The way of conserving excavated features can be largely categorized into on-site conservation and transfer conservation. On-site conservation means to conserve excavated features as they were at the excavation site. It can be further categorized into soil-covered on-site conservation, in which excavated features are covered with soil to prevent them from being damaged, and exposed on-site conservation in which the features were conserved as they were exposed. Transfer conservation is operated on the premise that excavated features are transferred to another place. It can be further categorized into original form transfer, transcribing transfer, reproduction transfer, and dismantlement transfer. Original form transfer refers to the method of moving the original forms of excavated features to another place. Transcribing transfer refers to moving some of the surfaces of excavated features to another place. Reproduction transfer refers to restoring the forms of excavated features in another place after copying the forms of excavated features at the excavation site. Dismantlement transfer refers to the method of restoring excavated features in a place other than the excavation site in the reverse order of dismantlement after dismantling the features at the excavation site. The most fundamental issue regarding conserving excavated features is the conservation of their original forms. However, the conservation of excavated features tends to be decided depending on a variety of conditions such as society, economy, culture, and local situations. In order to conserve excavated features more effectively, more detailed and specialized conservation methods should be created. Furthermore, continuing research is needed to find the most effective way of conserving them through exchange with other neighboring academic fields and scientific technology.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.5
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• pp.10-21
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• 2006

For analyze of the bearing capacity, skin friction and settlements of pile on axial compressive loading, both Load transfer tests of pile and pile loading test in field have application to commonly before pile installing. A bearing capacity of pile was affected by the characteristics of surrounding ground of pile. Especially, that is very different because of evaluation of settlement due to each soil conditions of ground depths. The ground characteristics using evaluation of bearing capacity of pile through load transfer analysis depends on N values of SPT, and then a bearing capacity of pile installed soft ground and refilled area may be difficult to rational evaluation. An evaluation of bearing capacity on pile applied axial compressive loading was effected by strength of ground installed pile, unconfined compressive strength at pile tip, pile diameter, rough of excavated surface, confining pressure and deformation modules of rock etc and these are commonly including the unreliability due to slime occurred excavation works. Load transfer characteristics considered ground conditions take charge of load transfer of large diameter pile was investigated through case study applied load transfer tests. To these, matrix analytical technique of load transfer using finite differential equation developed and compared with the results of pile load test.