• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.2
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• pp.1965-1970
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• 1970

The experiment was carried out in order to improve the leakage stopping work in the irrigation canal founding on the porous soil. But the experiment had many problems to be studied more owing to the insufficient time and facilities. The results obtained are summarized as follows; 1. Polyethylene film is estimated not to make strength decrease owing to buring in the subsoil, but to make owing to the sunlight. 2. Coated nylon shows the tendency to deteriorate strength when it is buried in the earth or exposed to the sun for long time, but leakage is all but impermeability generally. 3. Leakage loss rates for one hour show some differences in the canal to be full with water in accordance with operating methods, that is, the clay lining section is 12.6%, the coated nylon lining section is 1.7%, the polyethylene film lining section is 1.3%, respectively. 4. Leakage quantities per wetted perimeter unit area show $3.556cc/cm^2/hr$. in the clay lining section, $1.574cc/cm^2/hr$. in the coated nylon section, $0.695cc/cm^2/hr$. in the polyethylene film lining section, respectively. 5. When the construction fund make the clay lining section as a standard, the polyethylene film section is 92.1%, the coated nylon section is 174.2%, respectively. But, the unit cost of execution may be low when the polyethylene film and the coated nylon will enable to mass-produce for the purpose of execution.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.222-225
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• 2001

In urban environments, the surface land impermeability fundamentally related to urban growth emphasizes the environmental problems such as the storm water peak flow (so-called the urban flooding) and the pollution. The conventional urban drainage system provides a number of temporary reservoirs intercepting and retaining surface-derived pollutants following their introduction to and deposition upon the impermeable surface. Gully-pots are common features in urban drainage systems in Korea, which were installed for draining rainwater to prevent regurgitation in rainy season and retaining larger particles, hence minimizing pipe blockage problems. When the road runoff conveying sediment enters a gully-pot, the sediment mixes with the gully liquor causing direct pollution of receiving waters. The characteristics of local sediment contamination are usually related to the types of land use activities that take place or have taken place within the area., This study was undertaken to evaluate the spatial and temporal variations of the contamination of gully-pot sediments in Seoul with respect to heavy metals such as As, Cd, Co, Cr, Ni, Pb, Cu and Zn. The heavy metal data were examined according to the land use type. In this paper, sampling sites in Seoul were divided into six groups (commercial area, industrial area, residental area, motor way, rural area, and local pollution).

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.137-143
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• 2010

This research is a comparative analysis of the surface gloss of concrete depending on the coating material added to the cast, and includes analyses of the surface gloss of specimens made of cement mortar, with and without the addition of superplasticizer. In terms of coating material, the 7th material, which is part of a liquid packaging material, was shown to have the highest gloss, and was followed by the 3rd material, which uses transparent film. As the level of gloss is shown to vary depending on the material used for the coating film, it can be interpreted that the surface gloss can differ depending on surface particles and chemical composition factors. To make a concrete surface smooth, it is more effective to use a coating material with impermeability and a highly dense surface.

• Journal of the Korean Geosynthetics Society
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• v.6 no.2
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• pp.9-15
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• 2007

Bedding zone in CRFD (Concrete Faced Rockfill Dam) requires bearing capacity to support the concrete face slab uniformly. Also, shear strength which is a key factor in slope stability and impermeability which is to prevent a loss of soils in case of leakage of concrete slab face are needed. In this study, trial prototype construction for bedding zone in CRFD was performed to investigate the compaction characteristics of bedding zone according to the frequency of compaction, water contents and so on. As a results of series of field test, the compaction characteristics of bedding zone in CRFD was affected considerably by the depth of compaction layer and frequency of compaction.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.403-430
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• 2016

This paper studies the dynamics of the lineal-located time-harmonic moving-with-constant-velocity load which acts on the hydro-elastic system consisting of the elastic plate, compressible viscous fluid - strip and rigid wall. The plane-strain state in the plate is considered and its motion is described by employing the exact equations of elastodynamics but the plane-parallel flow of the fluid is described by the linearized Navier-Stokes equations. It is assumed that the velocity and force vectors of the constituents are continuous on the contact plane between the plate and fluid, and impermeability conditions on the rigid wall are satisfied. Numerical results on the velocity and stress distributions on the interface plane are presented and discussed and the focus is on the influence of the effect caused by the interaction between oscillation and moving of the external load. During these discussions, the corresponding earlier results by the authors are used which were obtained in the cases where, on the system under consideration, only the oscillating or moving load acts. In particular, it is established that the magnitude of the aforementioned interaction depends significantly on the vibration phase of the system.

• Elastomers and Composites
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• v.55 no.3
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• pp.199-204
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• 2020

Considering the immense applicability of isoprene rubbers, such as natural rubber (NR) and synthetic polyisoprene rubber (IR), attempts are being made to introduce more functionality within the rubber structure, e.g. epoxidation, to widen their technological viability. Epoxidation introduces polar epoxy bonds into the rubber molecular chain, resulting in enhanced intermolecular interactions among the rubber chains, increasing the oil resistance and air impermeability. Although there have been many reports on the epoxidation of NR in its latex form, there has been no such report using its solid form (or gum), which limits the epoxidation in terms of portability. Furthermore, the gum form has longer lifetime, while the latex form has limited lifetime for its efficient use. In this study, the epoxidation of natural rubber and polyisoprene rubber (using meta-chloroperoxybenzoic acid (mCPBA) as the epoxidizing agent) by dissolving their gum in hexane (i.e., the solution method) have been studied and compared. The effects of the amount of mCPBA, reaction time, and reaction temperature were investigated. The present process is easy and facilitates the epoxidation of rubbers in their solid form; therefore, it can be used for industrial upscaling of epoxidized rubber production.

• Computers and Concrete
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• v.13 no.4
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• pp.423-436
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• 2014

Ground Granulated Blast Furnace Slag (GGBFS) is widely used as an effective partial cement replacement material. GGBFS inclusion has already been proven to improve several performance characteristics of concrete. GGBFS provides enhanced durability, including high resistance to chloride penetration and protection against alkali silica reaction. In this paper results of an experimental research work on influence of low-reactivity GGBFS (which is largely available in Iran) on the properties of mortars and concretes are reported. In the first stage, influence of GGBFS replacement level and fineness on the compressive strength of mortars was investigated using Taguchi method. The analysis of mean (ANOM) statistical approach was also adopted to develop the optimal conditions. Next, based on the obtained results, concrete mixtures were designed and water penetration, capillary absorption, surface resistivity, and compressive strength tests were carried out on highstrength concrete specimens at different ages up to 90 days. The results indicated that 7-day compressive strength is adversely affected by GGBFS inclusion, while the negative effect is less evident at later ages. Also, it was inferred that use of low-reactivity GGBFS (at moderate levels such as 20% and 30%) can enhance the impermeability of high-strength concrete since 28 days age.

• Structural Engineering and Mechanics
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• v.29 no.1
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• pp.91-111
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• 2008

This paper outlines the development of a computational model in order to analyze the dynamic behaviour of coupled fluid-structure systems such as a) liquid containers, b) a set of parallel or radial plates. In this work a hybrid fluid-solid element is developed, capable of simulating both membrane and bending effects of the plate. The structural mass and stiffness matrices are determined using exact integration of governing equations which are derived using a combination of classical plate theory and a finite element approach. The Bernoulli equation and velocity potential function are used to describe the liquid pressure applied on the solid-fluid element. An impermeability condition assures a permanent contact at the fluid-structure interface. Applications of this model are presented for both parallel and radial plates as well as fluid-filled rectangular reservoir. The effect of physical parameters on the dynamic behaviour of a coupled fluid-structure system is investigated. The results obtained using the presented approach for dynamic characteristics such as natural frequency are in agreement to those calculated using other theories and experiments.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.53-59
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• 2016

Considering the chemical reaction between concrete which is the raw material of the dike bottoms and hazardous chemicals, some chemicals can have negative effects on the impermeability of concrete dike bottoms. The impermeable standards for the concrete bottom of dikes have been made in the recent study, but the previous study was based on the exposure test to crude oil which is not corrosive and not related to the chemical reaction. It can be concluded that the test of crude oil can't represent all kinds of hazardous chemicals, especially highly corrosive chemicals. Meanwhile, this study has conducted the exposure test to nitric acid that is strongly corrosive and very hazardous. The results have showed that nitric acid has been penetrated at the maximum penetration depth of 2.9 cm for 7 days and the impermeable standards are better than the germany standard. Through this study with severe chemical, the scientific basis on the installation standards of all dike bottoms which are generally used in the industry has been obtained.

• Structural Engineering and Mechanics
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• v.81 no.4
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• pp.443-459
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• 2022

The paper studies the dispersion and attenuation of propagating waves in the "plate+compressible viscous fluid layer" system in the case where the fluid layer flow is restricted with a rigid wall, and in the case where the fluid layer has a free face. The motion of the plate is described by the exact equations of elastodynamics and the flow of the fluid by the linearized Navier-Stokes equations for compressible barotropic Newtonian viscous fluids. Analytical expressions are obtained for the amplitudes of the sought values, and the dispersion equation is derived using the corresponding boundary and compatibility conditions. To find the complex roots of the dispersion equation, an algorithm based on equating the modulus of the dispersion determinant to zero is developed. Numerical results on the dispersion and attenuation curves for various pairs of plate and fluid materials under different fluid layer face conditions are presented and discussed. Corresponding conclusions on the influence of the problem parameters on the dispersion and attenuation curves are made and, in particular, it is established that the change of the free face boundary condition with the impermeability condition can influence the dispersion and attenuation curves not only in the quantitative, but also in the qualitative sense.