• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6B
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• pp.709-721
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• 2008

This paper is to test the applicability of ModKIMSTORM (Modified KIneMatic Wave STOrm Runoff Model) by applying it to Namgangdam watershed of $2,293km^2$. Model inputs (DEM, land use, soil related information) were prepared in 500 m spatial resolution. Using five typhoon events (Saomi in 2000, Rusa in 2002, Maemi in 2003, Megi in 2004 and Ewiniar in 2006) and two storm events (May of 2003 and July of 2004), the model was calibrated and verified by comparing the simulated streamflow with the observed one at the outlet of the watershed. The Pearson's coefficient of determination $R^2$, Nash and Sutcliffe model efficiency E, the deviation of runoff volumes $D_v$, relative error of the peak runoff rate $EQ_p$, and absolute error of the time to peak runoff $ET_p$ showed the average value of 0.984, 0.981, 3.63%, 0.003, and 0.48 hr for 4 storms calibration and 0.937, 0.895, 8.08%, 0.138, and 0.73 hr for 3 storms verification respectively. Among the model parameters, the stream Manning's roughness coefficient was the most sensitive for peak runoff and the initial soil moisture content was highly sensitive for runoff volume fitting. We could look into the behavior of hyrologic components from the spatial results during the storm periods and get some clue for the watershed management by storms.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.218-223
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• 2016

The calculation method of ground heat exchange in greenhouses has different ideas in each design standard, so there is a big difference in each method according to the size of greenhouses, it is necessary to establish a more accurate method that can be applied to the domestic. In order to provide basic data for the formulation of the calculation method of greenhouse heating load, we measured the soil temperature distribution and the soil heat flux in three plastic greenhouses of different size and location during the heating period. And then the calculation methods of ground heat exchange in greenhouses were reviewed. The soil temperature distributions measured in the heating greenhouse were compared with the indoor air temperature, the results showed that soil temperatures were higher than room temperature in the central part of greenhouse, and soil temperatures were lower than room temperature in the side edge of greenhouse. Therefore, it is determined that the ground heat gain in the central part of greenhouse and the perimeter heat loss in the side edge of greenhouse are occurred, there is a difference depending on the size of greenhouse. Introducing the concept of heat loss through the perimeter of building and modified to reflect the size of greenhouse, the calculation method of ground heat exchange in greenhouses is considered appropriate. It was confirmed that the floor heat loss measured by using soil heat flux sensors increased linearly in proportion to the temperature difference between indoor and outdoor. We derived the reference temperature difference which change the direction of ground heat flow and the perimeter heat loss factor from the measured heat flux results. In the heating design of domestic greenhouses, reference temperature differences are proposed to apply $12.5{\sim}15^{\circ}C$ in small greenhouses and around $10^{\circ}C$ in large greenhouses. Perimeter heat loss factors are proposed to apply $2.5{\sim}5.0W{\cdot}m^{-1}{\cdot}K^{-1}$ in small greenhouses and $7.5{\sim}10W{\cdot}m^{-1}{\cdot}K^{-1}$ in large greenhouses as design standard data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.167-176
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• 1991

Finite element programs are developed, adopting the hyperbolic model and the Cam-clay model. In the hyperbolic model, a new model taking into account the volume change during shear is proposed and a new technique considering the density change underneath a footing is proposed. And a computing algorithm considered as more reasonable than existing one is presented. In the Cam-clay model, the deveoloped program is applied to sand, the case not recorded much, and then it is tried to analiza the behavior of sand from the viewpoint of the critical state concept. For this, the conventional CD triaxial compression tests and the footing model tests are carried out. The results are improved by 60 percent by using the modified hyperbolic model proposed. When the Cam-clay model is applied to sand, a model reflecting the overconsolidation effects and a computing algorithm accounting for the strain softening are needed. The results obtained by using the Cam-clay model are not much influenced by the value of the initial poisson's ratio, but those of the modified hyperbolic model are much influenced by that. So th values of the initial poisson's ratio must be selected deliberately in the numerical analysis.

• Journal of the Korean Geotechnical Society
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• v.21 no.4
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• pp.31-40
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• 2005

This study proposed a new yield function considering the spacing ratio of the critical state to predict the undrained shear behavior of anisotropic field ground. We have suggested a nonassociated constitutive model that used a newly modified plastic potential function in order to apply the yield function of the modified Cam-Clay model to the anisotropic consolidation. In this paper, we predicted undrained shear behavior of the remolded weathered mudstone soils in Phohang isotorpically and anisotropically consolidated using the suggested model. To evaluate the reliability of proposed model, we predictied undrained shear behavior of Bankok Clay isotropically, nomally consolidated and Drammen Clay Ko consolidated. The predicted results are consistent with the observed behavior.

• Journal of the Korean Society of Tobacco Science
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• v.2 no.1
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• pp.53-60
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• 1980

Biological and serological assays were conducted with overwintered roots of tobacco and red pepper, capsule of tobacco, and several species of weeds in order to check whether those tissue could serve as a natural source of effection of tobacco mosaic virus (TMV) to field tobacco plants in the spring. Also in this study TMV occurrence was surveyed at several different stages of tobacco growth to see if a natural source discussed above has anything to do with actual appearance of TMV at fields. The results are as follows 1) The most critical period for TMV infection was the time when tobacco plants were handled with human hands; in the case of the modified polyethylene film mulching system it was at transplantation and when this modified system was changed to the regular system, and, in the case of the regular polyethylene film mulching system, the time was at transplanting and at primary sucker control by hands. 2) Roots of tobacco and red pepper were found to carry infective TMV even after overwintering in the soil. 3) Out of 38 weed species belonging to 22 families examined, only two species, Solanum nigrum and Physalis alkekengi var. franchetii were shown to be naturally infected with TMV. 4) TMV was isolated from capsule tissue, but not from immature anther of tobacco.

• Journal of the Korean Geotechnical Society
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• v.21 no.9
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• pp.77-86
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• 2005

Since slope sliding and loss of railway triggered by a rainfall produce instability in the operation of trains, a proper method to estimate the slope stability considering rainfall Is required. from the field study, sliding induced by rainfall depends on the engineering properties of soils, three dimensional aspect of the slope, rainfall intensity and geological conditions of the soil layers. In this study, among various types of sliding, slope Instability caused by the surface runoff water at the concave zones in a slope is investigated. The depth of runoff water is calculated by using the Rational method and Manning equation. The occurrence of runoff water is evaluated by a comparison between the calculated infiltration rate and rainfall intensity. Pressure heads which can be calculated from the modified Iverson model are used to calculate the factor of safety along the vertical depth of the slope. The modified Iverson model considers the depth of runoff water, thus the maximum hydraulic gradient along the depth of slope is greater than one.

• Economic and Environmental Geology
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• v.27 no.5
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• pp.469-477
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• 1994

Many researchers have investigated most representative sequential extraction method using various reagents for determining the chemical forms of metals in soils and sediments. In this paper, a newly modified method for sequential extraction scheme based on Tessier's method by Environmental Geochemistry Research, Centre for Environmental Technology, Imperial College, was introduced and examined. In comparison with Tessier's method, originally designed for sediment analysis by Atomic Absorption Spectrophotometry (AAS), the sequential extraction scheme has been developed for the multi-element analysis by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The partitioning of particulate trace elements was classified into five fractions: (i) exchangeable, (ii) bound to carbonates or specially adsorbed, (iii) bound to Fe and Mn oxides, (iv) bound to organic matter and sulphides and (v) residuals. The experimental results of the pilot study for in-house reference material (HRM2) and certified international standard reference material (SRM2711) using the modified method showed not only reasonable precision and accuracy but also acceptable overall recovery rates. In addition, mine dump soils sampled in the Dalsung Cu-W mine, Korea were prepared and sequentially extracted using the method. Most of Cu was bound to organic matter/sulphides and residual fractions. The dominant fraction of soil Pb and Zn in the study area was found in the residuals. The fraction of Cd showed a wide variation between samples and could be found bound to the carbonates or specially adsorbed, oxides, organic fraction and residuals. The recovery rates of Cd, however, were poor due to relatively low Cd concentrations in soils. The heavy metals in these mine dumps appear to be in the more inert forms and should not be readily bioavailable. The soils, however, had very low pH values (average 4.1) and had sandy textures; consequently, rapid infiltration of rainfall may increase leaching of Zn and Cd which were found to be around 5 to 10% of the exchangeable fraction. As a result of the investigation of this study, it has been strongly recommended that these mine waste materials should still be considered a significant contaminant source and will need environmental remediation to prevent pollutants from being released into the environment.

• Microbiology and Biotechnology Letters
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• v.14 no.3
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• pp.239-244
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• 1986

To develop the potential use as new host strain for gene cloning, alkaline-tolerant isolates from soil were examined for amylase activity, protease activity, antimicrobial activity and transformability by using plasmid pUB 110. Of these strains, one was selected and identified as Bacillus sp. YA-14. in the enzymatic properties of Bacillus sp. YA-14 the optimal conditions for the reaction of amylase and protease were at pH 0.8 and pH 7.5 respectively. The antimicrobial activity of Bacillus sp. YA-14 was also found. For the transformation, Bacillus sp. YA-14 was cultured to late logarithmic growth phase ai 37$^{\circ}C$ in modified SPI medium (pH 8.0) containing 0.4% MgSO$_4$. The presence of pUB 110 plasmid DNA in transformants was confirmed by electrophoresis and stably maintained in the new host.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.31-40
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• 2008

The dynamic moduli of asphalt concrete are very important for the analysis and the design of asphalt pavement systems. The dynamic modulus master curve is usually represented by a sigmoidal function. The Ramberg-Osgood model was widely used for fitting of normalized modulus reduction curves with strain of soils in soil dynamic fields. The master curves were obtained by both sigmoidal functions and modified Ramberg-Osgood model for the same dynamic modulus data set, the fitting abilities of both methods were excellent. The coefficients in sigmoidal function are coupled. Therefore, it is not possible to separate the characteristics of the master curve with absolute value and shape. However, the each fitting coefficient in the Ramberg-Osgood model has a unique effect on the master curve, and the coefficients are not coupled with each other.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.161-169
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• 2011

The objective of this study was to evaluate the efficiency of a modified filtration system treating non-point source (NPS) pollutants. The developed Best Management Practice (BMP) technology was designed based on the geographical and climatic characteristics of the site. A lab-scale test experiment was conducted using three different hydraulic loading rates representing the first flush flow, average flow and overflow conditions during a rainfall event. Water quality analysis was performed on the water samples taken at the inflow, outflow and infiltration during the test experiment of the lab-scale BMP. Also, the water and mass balance at different hydraulic loading rates was determined. Results from the lab-scale test experiment showed that the lab-scale BMP had a high removal efficiency of 80-90% for all NPS pollutants. The overflow test condition obtained the lowest removal efficiency among the hydraulic loading rates because it gave less opportunity for the pollutants to be filtered and retained inside system. The infiltration ratio was approximately 1 % of the inflow and outflow. Increasing the infiltration ratio requires technical approach of soil amendment where the BMP is installed.