• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.99-108
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• 2018

An oil-tolerant and salt-resistant aqueous foam system was screened out as a possible lubricant to enable cold heavy oil transportation. The microstructures and viscoelasticity and effects of heavy oil, salt and temperature on the foam stability were investigated and new rheological and drainage models were established. The results indicate the foam with multilayered shells belongs to a special microcellular foam. The viscoelasticity could be neglected due to its low relaxation time. The drainage process can be divided into three stages. The foam with quality of 67.9% maintains great stability at high oil and salt concentrations and appropriate elevated temperature.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.211-214
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• 2007

The purpose of this study was to establish the basic information for natural drainage capacity assessment in urban area. We sorted midium watershed of Han river and Nak-dong river, and selected 30 rainfall events during 1995 to 2000 according to high level of damage. The inundated area showed high watershed slope about 25% and it indicated the greatest damage around the watershed located in 200-300m of altitude. Besides, the great damage by inundation was occurred in the mountainous agriculture region, where the forest scale was high and the urbanization was being progressed gradually. However, inundated area was small in case of grassland, water tone such as riparian area, bare ground and wetland. Moreover, the inundated area was different according to river shape and characteristics of river distribution such as the density of the stream order, conservation constant of the river system, and the number of undulations in the watershed. Therefore, it showed that land use, river shape and distribution characteristics of stream influence on inundation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.1
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• pp.52-60
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• 1999

Drainage rate in wet-end, which has significant influences on the production capacity, product quality and process economics in papermaking, becomes an important factor in the modern high speed papermaking processes owing to increased level of fines contained in today's pulp materials and increased papermaking system closure. A study was carred out to investigate the influence of beating and fines content on natural and vacuum dewatering using a vacuum drainage tester. Increase in beating and accumulation of fines in the stock decreased natural dewatering, Vacuum dewatering effect, however, increased substantially as beating and fines content were increased. But this increase in vacuum dewatering decreased again when a stock is severely beaten or fines content is greater than 35%. Above this level of fines content, mobile fines migrates to the interstices of the forming web to cause sealing or plugging which restrict fluid movement through the web.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.5
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• pp.170-180
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• 2000

The surface-drainage system, which consists of bio-swale and detention-infiltration Basins and carries out the function of temporary detention-infiltration of runoff, is defined as the "natural drainage system". It is an environmentally sound and economically beneficial practice to reduce run-off by retaining it in swales as much as possible and letting run-off infiltrate into the ground. In order to estimate appropriate capacity of swales, it is necessary to know how long will it take for certain depths of water to infiltrate. The ponding times, or infiltration times, of various depths and of various soil textures, could be estimated with the Green-Ampt Infiltration Model. Included soil textures are loamy sand, sandy loam, loam, silty loam, sandy clay loam and clay loam. Ponding depths are from 10cm to 100cm intervals. Newton-Raphson method is used for the solution of the Green-Ampt equation by a computer program. The computer program was written with the FORTRAN Developer 4.0 v.. Selected ponding depth is acceptable when the sum of the ponding time and the breeding time of mosquitoes is less than the tolerance period of innundation of grasses and trees.and trees.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.623-631
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• 2011

In recent decade, the occurrences of typhoon and severe storm events are increasing trend due to the climate change. And the intensity of natural disaster is more and more stronger and the loss of life and damage of property are also increasing. Therefore, this study tried to understand the impact of climate change on urban drainage system for prevention and control of natural disaster and for this, we selected Gyeyang-gu, Incheon city as a study area. We investigated the climate models and scenarios for the selection of proper model and scenario, then we estimated frequency based rainfall in hourly unit considering climate change. The XP-SWMM model was used to estimate the future flood discharge on urban drainage system using the estimated frequency based rainfall. As a result, we have known that the study area will be overflown in the future and so we may need prepare proper measures for the flood prevention and control.

• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.75-89
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• 2001

There are 334 coal mines and about 900 metal mines abandoned. The environmental problems such as acid mine drainage from adits etc. and the subsidence has occurred in the abandoned mines. In addition, soil has been contaminated by tailings. According to analysis of mine drainages, some of them from adits in the abandoned coal and metallic mines were acidic and polluted by heavy metals. Especially, water quality of coal mine drainages were different by areas. Treatment of mine drainage by conventional chemical treatment has the drawback because the operating cost is very expensive. The treatment system used in mine drainage is the natural treatment system such as anoxic limestone drain in adits and the constructed wetland. The method of reclamation for abandoned waste rocks and tailings impoundments are mainly landfilling.

• Journal of Korea Water Resources Association
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• v.52 no.4
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• pp.301-312
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• 2019

The importance of the dual drainage system model has increased as the urban flood damage has increased due to the increase of local storm due to climate change. The dual drainage model is a model for more accurately expressing the phenomena of surface flow and conduit flow. Surface runoff and pipe runoff are analyzed through the respective equations and parameters. And the results are expressed visually in various ways. Therefore, inundation analysis results of dual drainage model are used as important data for urban flood prevention plan. In this study, the applicability of the COBRA model, which can be interpreted by combining the dual drainage system with the natural watershed and the urban watershed, was investigated. And the results were compared with other dual drainage models (XP-SWMM, UFAM) to determine suitability of the results. For the same watershed, the XP-SWMM simulates the flooding characteristics of 3 types of dual drainage system model and the internal flooding characteristics due to the lack of capacity of the conduit. UFAM showed the lowest inundation analysis results compared with the other models according to characteristics of consideration of street inlet. COBRA showed the general result that the flooded area and the maximum flooding depth are proportional to the increase in rainfall. It is considered that the COBRA model is good in terms of the stability of the model considering the characteristics of the model to simulate the effective rainfall according to the soil conditions and the realistic appearance of the flooding due to the surface reservoir.

• Journal of Soil and Groundwater Environment
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• v.27 no.4
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• pp.10-21
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• 2022

In the South Korea, 47% of abandoned mines are suffering from the mining hazards such as the mine drainage (MD), the mine tailings and the waste rocks. Among them the mine drainage which has a low pH and the high concentration of heavy metals can directly contaminate rivers or soil and cause serious damages to human health. The natural/artificial treatment facilities by using neutralizers and coagulants for the mine drainage have been operated in domestic and most of heavy metals in mind drainage are precipitated and removed in the form of metal hydroxide, alumino-silicate or carbonate, generating a large amount of mine drainage treated sludge ('MDS' hereafter) by-product. The MDS has a large surface area and many functional groups, showing high efficiency on the fixation of heavy metals. The purpose of this study is to develop a ingenious heavy metal stabilizer that can effectively stabilize arsenic (As) and heavy metals in soil by recycling the MDS (two types of MDS: the acid mine drainage treated sludge (MMDS) and the coal mine drainage treated sludge (CMDS)). Various analyses, toxicity evaluations, and leaching reduction batch experiments were performed to identify the characteristics of MDS as the stabilizer for soils contaminated with As and heavy metals. As a result of batch experiments, the Pb stabilization efficiency of both of MDSs for soil A was higher than 90% and their Zn stabilization efficiencies were higher than 70%. In the case of soil B and C, which were contaminated with As, their As stabilization efficiencies were higher than 80%. Experimental results suggested that both of MDSs could be successfully applied for the As and heavy metal contaminated soil as the soil stabilizer, because of their low unit price and high stabilization efficiency for As and hevry metals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.511-517
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• 2006

Flood damage is one of the most important and influential natural disaster which has an effect on human beings. Local concentrated heavy rainfall in urban area yields flood damage increase due to insufficient capacity of drainage system. When the excessive flood occurs in urban area, it yields huge property losses of public facilities involving roadway inundation to paralyze industrial and transportation system of the city. To prevent such flood damages in urban area, it is necessary to develop adequate inundation analysis model which can consider complicated geometry of urban area and artificial drainage system simultaneously. In this study, an urban flood analysis model adopting the unstructured computational grid was developed to simulate the urban flood characteristics such as inundation area, depth and integrated with subsurface drainage network systems. By the result, we can make use of these presented method to find a flood hazard area and to make a flodd evacuation map. The model can also establish flood-mitigation measures as a part of the decision support system for flood control authority.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.66-72
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• 2016

The applicability of rice husk fiber as a raw material for eco-friendly pulp mold was evaluated in this study. The higher demand of environmental friendly packaging material resulted in the more interest for the natural fiber based pulp mold. The rice husk which is an abundant agricultural byproduct in Asia could be defiberized by an alkaline digestion process. The changes in the pulp mold making process and the properties of pulp mold by the addition of the rice husk were investigated. The addition of rice husk fiber to the pulp mold made with OCC or UBKP resulted in the increase in drainage at the pulp mold forming process. In case of UBKP pulp mold, the addition of rice husk fiber increased the drying efficiency after pulp mold forming since the structure of pulp mold became more bulkier by the addition of the rice husk fiber. Those results showed the rice husk fiber could be applied to the pulp mold manufacturing as one of the eco-friendly natural fiber resources.