• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.129-138
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• 2002

This paper presents a study on the discharge capacity of geotextiles as a horizontal drain layer placed between the layers of earth fill and natural soft ground. Required discharge capacity of geotextiles as drain layers estimated by consolidation analysis is proportional to the consolidation coefficient of the ground soils and the width of the earth fills. The field discharge capacity of the geotextiles are measured by the hydraulic transmissivity test. And the results show wide variation according to the material characteristics of geotextiles, water content of the soils, vertical pressure, and etc. For the short horizontal drain length, geotextile filter mat can be used for the horizontal drain layer. And f3r the long drain($25{\sim}55m$), it is used for the drain together with Bord Drain.

• Geotechnical Engineering
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• v.13 no.2
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• pp.39-54
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• 1997

Laboratory testings were carried out on plastic board drains (PBDs) using large scale test apparatus to evaluate the physical properties and the drainage performance. The test results reveal that the domestic products of PBDs are well compared with the foreign prod acts as far as the quality and drainage performance are concerned. It has also been confirmed that the discharge capacity decreases with time in such a way that the air bubbles are entrapped inside kinky PBDs and these air bubbles block the water flow through PBDs. It has been found that the vacuum pressure iseffectively applicable to recover the discharge capacity affected by the entrapped air bubbles.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.111-115
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• 2001

Durability of tunnel drains is important, because the accumulation of groundwater around the tunnel due to clogging of filter or reduction of discharge capacity of drain causes reduction of the life time of tunnel linings. In this paper, clogging and discharge capacity of drain and filter of tunnels are evaluated using a gradient ratio test and filter design criteria. The results of the gradient ratio test showed that gradient ratio(GR) is high when fine content is high in the soil samples and equivalent opening size(EOS) of filter materials is small. Measured GR was less than allowable critical gradinet ratio : 3.0, which is the clogging criteria of U.S. Army Corps of Engineers.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.09a
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• pp.9-16
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• 2000

Applicability of the cross shaped drain in a soft clay ground is examined using the laboratory discharge capacity test, column consolidation test and 3-D numerical flow analysis. The equivalent diameter of the tested drains is back-calculated from the laboratory experiment and compared with those calculated from the formula suggested in the literature. The effective range of the cross shaped drain about the discharge capacity and coefficient of permeability is analyzed. The results of numerical analysis show that the cross shaped drain which has a cross-sectional area twice of the band shaped drain can reduce the consolidation time by 30% from that for the band shaped drain in a soft clay ground that K is over 1${\times}$10$\^$-7/cm/sec

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.351-354
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• 2000

AC impedance of LiM $n_2$ $O_4$ and LiM $g_{0.1}$M $n_{1.9}$ $O_4$ samples have been studied at various temperature with charge-discharge test. AC impedance of LiM $n_2$ $O_4$ measured at -2$0^{\circ}C$, room temperature and 5$0^{\circ}C$ revealed that initial impedance before charge-discharge test was gradually decreased and become small by becoming law temperature. It indicates that the Li ion diffusion and the transfer resistance of the cathode are related to the temperature of cycling. Impedance at high temperature was suddenly increased because Mn dissolution and decomposition of electrolyte had been increased during cycling, compared to impedance at low temperature. Therefore, charge-discharge capacity was suddenly decreased at high but was slowly at low. In LiM $g_{0.1}$M $n_{1.9}$ $O_4$, impedance and capacity were stability at room temperature than there at 5$0^{\circ}C$, too. Initial impedance at 5$0^{\circ}C$ before charge-discharge test was small and impedance was suddenly increased during cycling than that at room temperature.ure.ure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.636-643
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• 2006

Si-C materials were synthesized by the heating the mixture of silicon and polyvinylidene fluoride (PVDF). The electrochemical properties of the Si-C materials as the high capacitive anode materials of lithium secondary batteries were evaluated by the galvanostatic charge-discharge test through 2032 type $Si-C{\mid}Li$ coin cells. Charge-discharge tests were performed at C/10 hour rate(C = 372 mAh/g). Initial discharge and charge capacities of $Si-C{\mid}Li$ cell using a Si-C material derived from PVDF(20wt.%) were found to be 1,830 and 526 mAh/g respectively. The initial discharge-charge characteristics of the developed Si-C electrode were analyzed by the electrochemical galvanostatic test adopting the capacity limited charge cut-off condition(GISOC). The range of reversible specific capacity IIE(intercalation efficiency at initial discharge-charge) and IICs(surface irreversible specific capacity) were 216 mAh/g, 68 % and 31 mAh/g, respectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.2
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• pp.198-204
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• 2013

Acoustic emission(AE) signal was detected during charge and discharge of lithium ion battery to investigate relationships among cumulative count, discharge capacity, and microdamages. AE signal was received during accelerated charge/discharge cycle test of a coin-type commercial battery. A number of AE signals were successfully detected during charge and discharge, respectively. With increasing number of cycle, discharge capacity was decreased and AE cumulative count was observed to increase. Microstructural observation of the decomposed battery after cycle test revealed mechanical damages such as interface delamination and microcracking of the electrodes. These damages were attributed to sources of the detected AE signals. Based on a linear correlation between discharge capacity and cumulative count, feasibility of AE technique for evaluation of battery degradation was suggested.

• Journal of the Korean Geosynthetics Society
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• v.9 no.2
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• pp.11-20
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• 2010

This paper studies the discharge capacity of vertical drain boards that is controlling hydraulic gradient among many factors in the specification. The KS K 0940(2008), a testing method based on the conventional Delft type method for measuring the discharge capacity of a vertical drain, was specified in Korea Standard recently. In this test method, the variation in hydraulic gradient can result in large differences in the discharge capacity for the same vertical drain board.

• Journal of the Korean Geosynthetics Society
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• v.4 no.3
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• pp.3-10
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• 2005

This paper aims at investigating the characteristics of discharge capacity according to lateral pressure, hydraulic gradient and deformation of drain materials. A series of experiments were conducted to achieve this objective. In experiments, fiver drain boards as well as harmonica and castle types of drain boards were installed in a rubber membrane, and clay in sully was filled around them. The test results showed that the harmonica type of drain boards have the greatest discharge capacity comparing to castle and fiber drain boards. The results also indicated that the hydraulic gradient has more effect on reduction of discharge capacity than the lateral pressure.

• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.37-48
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• 2011

Recently, the social and environmental functions of nature river are important due to the increase of expectation for river restoration. So it should be considered the effect of vegetation affecting the conveyance capacity and hydraulic resistance. However, it has not yet proposed a objective standard and modeling method to estimate the effect of conveyance capacity according to vegetaion distribution in the watercourse such as water level or velocity. Therefore, this study simulates the variations of water level and velocity using 3-dimensional hydrodynamic model, EFDC, to consider a conveyance capacity in downstream of the Soyang Reservoir. The simulation results were validated using statistical index such as F-test and T-test. As results, the water level rises about 0.01 to 0.47m and velocity difference are about -0.95m/s to 0.23m/s.