• 한국해양학회지
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• v.10 no.2
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• pp.67-75
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• 1975

Tidal Flushing at the entrance channels of tidal bay or estuary in the central western coast of Korea; Gum River Estuary, Garorim Bay, Asan Bay, and Yeomha Estuary were studied with the recent data of current surveys measured by curret meter at three or five anchored stations along the section for one or two tidal periods at mean spring tide. Equilibrium relationship between tidal prism at mean spring tide and minimum flow area below the mean sea level of the channel in alluvial material was found as of O'Brien's (1931, 1969) study. Bed load transport in the tidal channel is balanced with the tidal flushing ability having a mean velocity of about 0.75m/sec or maximum velocity of about 1.25m/sec for a half tidal cycle over the section at mean spring tide which fairly agree with Brunn's study(1955, 1957). flushing actions for different hydraulic depth( mean depth) and bed material size in the channel were reviewed and found that it depend to a minor extent on the factors.

• Journal of Industrial Technology
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• v.19
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• pp.391-402
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• 1999

The numerical model predicting the behaviours of submerged mound constructed by dredged material is developed in this paper. The model is based on the Bailard's sediment transport formula, Stokes' second-order wave theory and the sediment balance equation. Nonlinear partial differential equation which is the same form as convection-dispersion equation which represents change of bed section can be obtained by substituting sediment transport equation for equation of sediment conservation. By this process, the analytical solution by which the characteristic of the behaviours of submerged mound can be estimated is derived by probably combining the convention coefficient and the dispersion coefficient governing the behaviours of submerged mound and the probability density function representing the wave characteristics. The validity of the analytical solution is verified by comparing the analytical solution which is assumed to estimate the movement rate submerged mound by bed-load with the field data of the past and its characteristic is analyzed quantitatively by obtaining the mean of the dispersion coefficient representing the extent of the decrease rate of the submerged mound height.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.58-65
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• 2003

The seismic response analysis of a freestanding spent fuel storage cask model are performed for an artificial time history acceleration generated by the basis on the US NRC RG1.60 response acceleration spectrum. This paper focuses on the structural stability by seismic loads to check the overturing possibility of storage cask and the slipping displacement on bed. Parametric analyses of a simplified cask model are performed to take into account the variations in seismic load magnitude and cask/bed interface friction. The analyses results show that the storage cask has a large marginal integrity in the response acceleration and slipping distance for both design seismic and beyond design seismic loads.

• International Journal of Railway
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• v.2 no.4
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• pp.180-186
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• 2009

High speed railway challenge the design, construction and maintaining of traditional railway, many traditional design concepts have been changed. Transition of railway and bridge has two main problems. one is that different lines have different ability of resisting distortion in area of trial load, which was known that problem of smooth transition of stiffness, the other is that differential settlement between artificial structure and earth structure cause bending of railway. The two problems have effect on train moving. The principle of processing transition of railway and bridge is same in world, but it is difficult to find relationship between design standard of transition, vehicle performance, line standard, design speed and so on form documentation and data reports. Based on mechanics, the paper analyzed dynamic performance of transition of high speed railway, studied various rough elements which is effective to train moving, built mathematical model of interaction of train and transition of high speed railway and developed numerical simulation software. In various different work conditions, we did great quantity of numerical simulation, comprehensive analysis and performance analysis.

• Analytical Science and Technology
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• v.8 no.4
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• pp.799-806
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• 1995

In industrial field, a large volume of regenerants (acid and caustic soda) and their washing effluents are regularly disposed off from the water demineralization plant during regeneration of the ion-exchanger units. Of these waste effluents, a part of the wash water discharged from the single bed Anion and Mixed Bed units can be utilized at a certain stage of their washing cycles when its conductivity is fallen down and becomes considerably less than that of the input raw water. The main aim of this specific waste effluent utilization is to dilute the TDS concentration of the input raw water (fed into the single bed ion-exchanger units) by blending. The achievement is the increase of the longevity of the production cycles of the I.E. units along with the improvement of the production quality and decrease of the regeneration frequencies. As a result, regenerant consumption would be saved because of the reduction of ionic load in feed water which will ultimately reduce the water purification cost. At the same time, the environment pollution will also be protected to a considerable extent. This operational measure is quite effective and useful specially where high TDS water is demineralized only by single bed ion-exchangers. In such case, the water treatment plant is very often found to suffer from both production quality and quantity in addition to carrying out of random and restless regenerations. Proper reuses of the aforesaid wash water effluents of the Anion and MB units excellently minimizes the difficulties experienced in practice. This paper contains the utilities and techniques of reuses of the different kinds of waste effluents of the industrial water treatment plant in addition to the specific reuses of the post-regeneration wash waters of the Anion and MB ion-exchanger units.

• Water for future
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• v.24 no.3
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• pp.49-60
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• 1991

As a second part of the study entitled "Field Measurement and Analysis of Fluvial Sediment in the Cheongmi-Strea", this study concerns mineralogical and contaminative characteristics of sediment particles collected at Wonbu-Gyo and Hanpyeong-Gyo in the Cheongmi-Stream. The mineralogical analysis of the bed sediment collected reveals that, in general , quarz is the most abundant mineral found in sands with feldspars and rock fragments in the next, which confirms what is known in the literature. The shape factor of sand particles is about 0.7, which also agrees to what is known in the foreign literature. The analysis also reveals that the clay particles collected are composed mainly of illite, kaolinate, and chlorite. The analysis of contamination reveals that there is no substantial difference between the contents of organic material and heavy metals in the surface water and those in the pore water beneath the river bed. It is because the sampling for this analysis was conducted right after the September flood during which the fresh top soil from the upstream watershed replaced the old bed sediment and pore water that would probably be more contaminated. The contents of geavy metals in the bed sediment of sand particles do not exceed those in the soils adjacent to the river. For fine sediment such as clays, however, the contents of heavy metals, especially of mercury and zinc, far exceed those in the soils adjacent to the river. These fine sediments are transported downstream in the form of wash load and deposited in part on flood plains, which could be a new source of contaminants.taminants.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.359-368
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• 2011

Purpose: Aquacel Ag$^{(R)}$ is a hydrofiber wound dressing integrated with ionic silver. Sorbact$^{(R)}$ is a hydrophobiccoated dressing that uses the hydrophobic interaction with microbes. In this study, we compared the wound healing effects and the antibacterial effects of Medifoam$^{(R)}$, Betadine soaked, Aquacel Ag$^{(R)}$ and Sorbact$^{(R)}$ dressings against MRSA-infected wounds. Methods: Eighty rats were divided into four groups: Medifoam$^{(R)}$; Betadine soaked; Aquacel Ag$^{(R)}$; and Sorbact$^{(R)}$. A $1.5{\times}1.5cm$ square full-thickness wound was made on the dorsum of each rat and infected with MRSA. Twenty-four hours thereafter, each dressing was applied to the wound and changed every other day. One, 3, 7, 11 and 15 days after the wound infection, swab culture grade, wound bed appearance score, and wound defect size change were evaluated, and 7 and 15 days after, histologic evaluation was compared between the groups. Results: The bacteria load of wounds in the Sorbact$^{(R)}$ group decreased earlier than in the other groups. The wound bed appearance score of the Sorbact$^{(R)}$ group also increased quicker, compared with the other groups. However, the size of wounds of the Aquacel Ag$^{(R)}$ group decreased more rapidly, compared with other groups. From the histologic point of view, there was no significant difference between Betadine soaked, Aquacel Ag$^{(R)}$ and Sorbact groups. Conclusion: The hydrophobic dressing using Sorbact$^{(R)}$ showed a more rapid reduction in the MRSA load and an elevation in the wound bed appearance score, but a slower decrease in wound size change due to detachment of wound bed tissue when the dressing was eliminated in the low exudate wound. The silver-containing hydrofiber dressing using Aquacel Ag$^{(R)}$ was more effective in ultimate wound size reduction, but some debris was trapped in the wound tissue and induced foreign body reaction in the high exudate wound. Thus, ongoing selection process of treatment based on the evaluation of the infectious wound state will be very important.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.258-265
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• 2009

To develop environmentally friendly constructed wetlands(CWs) for treating domestic sewage which was produced in farming and fishing village, the efficiency of water treatment at different ventilation systems in the vertical bed, depths of horizontal bed, and sewage loads was investigated. In the vertical bed, BOD and COD by duplex ventilation system were lower than those by single ventilation system. But T-N and T-P concentrations by both ventilation systems in the vertical bed were little different. In the horizontal bed, BOD, COD, T-N and T-P in 1.0 m and 1.3 m depths were little different. To reduce the CWs' area and to improve the pollutant removal efficiencies, the optimum depth of horizontal bed was 1.3 m. In single and duplex ventilation CWs, the removal rate of BOD, COD, SS, T-N and T-P decreased slightly with the sewage load increases. In same sewage load conditions, the removal rates of BOD, COD, SS, T-N and T-P by duplex ventilation CWs were higher than those by single ventilation CWs. In summary, to effectively treat domestic sewage from farming and fishing village, the optimum constructed wetlands would be the duplex ventilation CWs.

• Geomechanics and Engineering
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• v.29 no.6
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• pp.645-655
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• 2022

Granular columns have recently found widespread use in underground construction. The behaviour of granular columns under vertical loads has been extensively studied, specifically in relation to vertical load capacity obtained by bulging of the column body, including the behaviour after encasement of material. Determining the shear strength of loose soils reinforced with granular columns has received less attention. After the observations of lateral deformation near the toe of the embankment, attempts have been made to strengthen the lateral strength of granular columns. The purpose of this research is to look into the effects of different encasement conditions on the lateral load capacity of granular columns. This was accomplished by three-dimensional finite element analysis with FEM software. Various normal pressures and two different encasement configurations, namely single layer encasement and double layer encasement, with differing tensile strengths, were used in this study to determine their effect on lateral resistance. The failure envelope for a single column planted in loose sand was used to analyse the findings for three different granular column diameters, as well as the impact of different encasement conditions. According to the findings, the inclusion of a Granular Column enhanced the shear strength and overall stiffness of the loose sand bed, and the encasement of the Granular Column helped in deriving higher lateral resistance.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.2 s.21
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• pp.22-29
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• 2005

In this study we performed topology optimization and size optimization about support structure of pressure container which is installed in a Common Bed. The optimization study shows that structure weight optimization results can be applied to navy ship. The topology optimization is performed by static load, homogenization and optimality criteria method and size optimization is performed by SOL200 of NASTRAN.