• Title/Summary/Keyword: water surface slope

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THB EFFECT OF PRESSURE ON THE ELECTRICAL CONDUCTIVITY OF SEA WATER( I ) -The Specific Conductance of Sea Water under High Pressure- (해수의 전기전도도에 미치는 압력의 영향 ( I ) -고압하에서의 해수의 비전도도-)

  • KIM Chang-Yang;HWANG Kum-Sho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.10 no.4
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    • pp.205-212
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    • 1977
  • The properties of sea water in deep-sea are still quite poorly understood, even though those of the surface water have been sufficiently investigated. In this study, the specific conductance of sea water was measured under the circumstances : pressure of 1 to 2,000 bars and temperature 10 to $35^{\circ}C$ as well as over the concentration of 6.228 to 19.372 per mil chloronity. The specific conductance gave the linearity with the given pressure. The initial slope, ${\triangle}k/{\triangle}P$ of the specific conductance n versus the pressure P over the pressure 1 to 1,000 bars showed a large positive value, but the second slope over the pressure 1,000 to 2,000 bars was relatively less positive value. And our equations were comparable with the empirical formular obtained by Horns et al. (1963).

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A Study on Erosion Control Effect of Soil and Water Storable Pits (저사저수구(貯砂貯水溝)의 유토저지효과(流土沮止効果)에 관(關)한 연구(硏究))

  • Lee, Soo Wook;Lee, Tae Soo
    • Journal of Korean Society of Forest Science
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    • v.31 no.1
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    • pp.43-47
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    • 1976
  • This study was carried out to find out the effect of soil and water storable pits on reducing the surface runoff. 10 pits were digged in each plot of $50m^2$ along contour line. One kind of pits has a size of 30 cm width, 100cm length and 30cm depth, and the other has 30cm width, 100cm length and 20cm depth. 1. The soil and water storable pits have a significant effect on reducing surface runoff. Control plot had surface runoff 2.3-2.6 times more than the plots with pits. 2. There is no significant difference in surface runoff between 30cm depth pit and 20cm depth pit. 3. The soil and water storable pits did not have any effect on coverage, survival and growth of three species. 4. Steep slope had worse results than the other slopes in coverage, growth and fresh weight of experiment species.

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Conductivity and Surface Tension Behavior for Binary Mixtures over a Various Concentration of TTAB

  • Ahn, Beom-Shu
    • Journal of the Korean Applied Science and Technology
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    • v.23 no.2
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    • pp.160-168
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    • 2006
  • The conductances of trimethyltetradecylammonium bromide (TTAB) plus triphenyltetradecyl phosphonium bromide (TTPB) and TTAB plus trimethylhexadecylammonium bromide (HTAB) over the entire mole fraction range of TTAB were measured in water and in cyclodextrin plus water mixtures at fixed 4 and 8 mM of cyclodextrin at $30^{\circ}C$. The conductivity plot for both binary mixtures shows a single break from which the mixed critical micelle concentration and degree of micelle ionization were computed. From the slope of the conductivity curve, the equivalent ionic conductivities of the monomeric, associated, and the micelle states were calculated and discussed with respect to the surfactant-cyclodextrin complexation in the whole mole fraction range of both surfactant binary mixtures. The association constant K between the respective monomeric surfactant and cyclodextrin cavity of fixed 4 mM cyclodextrin was computed by considering 1:1 association from the surface tension measurement. A comparison among the K values for HTAB-cyclodetrin, TTAB-cyclodextrin, and TTPB-cyclodextrin shows that the former complexation is significantly stronger in comparison to the other ones due to the longer hydrophobic tail.

2-D Analysis of the Low Flow Variation Around the Bridge Pier (교각 주변의 저수류 (低水流) 흐름 변화에 대한 2차원 분석)

  • Yeon, In-Sung;Lee, Jai-Kyung;Yeon, Gyu-Bang
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.4
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    • pp.91-97
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    • 2009
  • The flow is changed by the structure which goes across the river. The structure with debris causes high water level and overflow. The changed flow, which caused by pier and stream characteristics like velocity and slope, was analysed by 2D model. After rainfall, the influences of increased discharge were evaluated. Velocity was simulated in the channel by SMS (Surface water Modeling System) using RMA2, and high velocity values were found in the steep and narrow reach. Highest velocity value around piers was showed in the middle of space between two piers. The increased discharge due to rainfall increases velocity and changes flow contour considerably.

Speed-up of Document Image Binarization Method Based on Water Flow Model (Water flow model에 기반한 문서영상 이진화 방법의 속도 개선)

  • 오현화;김도훈;이재용;김두식;임길택;진성일
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.4
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    • pp.75-86
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    • 2004
  • This paper proposes a method to speed up the document image binarization using a water flow model. The proposed method extracts the region of interest (ROI) around characters from a document image and restricts pouring water onto a 3-dimensional terrain surface of an image only within the ROI. The amount of water to be filed into a local valley is determined automatically depending on its depth and slope. The proposed method accumulates weighted water not only on the locally lowest position but also on its neighbors. Therefore, a valley is filed enough with only one try of pouring water onto the terrain surface of the ROI. Finally, the depth of each pond is adaptively thresholded for robust character segmentation, because the depth of a pond formed at a valley varies widely according to the gray-level difference between characters and backgrounds. In our experiments on real document images, the Proposed method has attained good binarization performance as well as remarkably reduced processing time compared with that of the existing method based on a water flow model.

BATHYMETRIC MODULATION ON WAVE SPECTRA

  • Liu, Cho-Teng;Doong, Dong-Jiing
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.344-347
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    • 2008
  • Ocean surface waves may be modified by ocean current and their observation may be severely distorted if the observer is on a moving platform with changing speed. Tidal current near a sill varies inversely with the water depth, and results spatially inhomogeneous modulation on the surface waves near the sill. For waves propagating upstream, they will encounter stronger current before reaching the sill, and therefore, they will shorten their wavelength with frequency unchanged, increase its amplitude, and it may break if the wave height is larger than 1/7 of the wavelength. These small scale (${\sim}$ 1 km changes is not suitable for satellite radar observation. Spatial distribution of wave-height spectra S(x, y) can not be acquired from wave gauges that are designed for collecting 2-D wave spectra at fixed locations, nor from satellite radar image which is more suitable for observing long swells. Optical images collected from cameras on-board a ship, over high-ground, or onboard an unmanned auto-piloting vehicle (UAV) may have pixel size that is small enough to resolve decimeter-scale short gravity waves. If diffuse sky light is the only source of lighting and it is uniform in camera-viewing directions, then the image intensity is proportional to the surface reflectance R(x, y) of diffuse light, and R is directly related to the surface slope. The slope spectrum and wave-height spectra S(x, y) may then be derived from R(x, y). The results are compared with the in situ measurement of wave spectra over Keelung Sill from a research vessel. The application of this method is for analysis and interpretation of satellite images on studies of current and wave interaction that often require fine scale information of wave-height spectra S(x, y) that changes dynamically with time and space.

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Damage Conditions and Assessment for Cut Slope Structures due to Acid Rock Drainage (산성암반배수에 의한 절취사면 구조물의 피해 현황과 평가)

  • Lee Gyoo Ho;Kim Jae Gon;Park Sam-Gyu;Lee Jin-Soo;Chon Chul-Min;Kim Tack Hyun
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.83-92
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    • 2005
  • The aim of this study was to investigate damage conditions of cut slope structures due to acid rock drainage (ARB) and to assess the acid production potential of various rocks. Acid rock drainage is produced by the oxidation of sulfide minerals contained in coal mine zone and mineralization belt of Pyeongan supergroup and Ogcheon group, pyrite-bearing andesite, and Tertiary acid sulfate soils in Korea. Most of cut slopes producing ARB have been treated with shotcrete to reduce ARD. According to the field observations, ARD had an adverse effect on slope structures. The corrosion of shotcrete, anchors and rock bolts and the bad germination and growth diseases of covering plants due to ARD were observed in the field. The concentration of heavy metals and pH of ARD from cut slope exceeded the environmental standard, indicating a high potential of environmental pollution of surrounding soil, surface water and ground water by the ARD. According to acid base accounting (ABA) of the studied samples, hydrothermally altered volcanic rocks, tuffs, coaly shales, tailings of metallic mine had a relatively high potential of acid production but gneiss and granite had no or less acid production potential. It is expected that the number of cut slopes will increase hereafter considering the present construction trend. In order to reduce the adverse effect of ARD in construction sites, we need to secure the data base for potential ARD producing area and to develop the ARD reduction technologies suitable.

Determining of Ground Condition Criteria for Dam Reinforced RIM Grouting (댐체 강화 RIM부 그라우팅을 위한 지반상태 기준 결정)

  • Han, Kiseung;Lee, Donghyuk;Park, Duhee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.2
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    • pp.181-186
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    • 2022
  • Dam slope RIM is a highly important contact interface where the main body and the base surface are connected. In general, when the grouting for the slope of the dam structure is designed, it is planned using limited data (drilling, geological map, etc.). This makes it very difficult to accurately consider the original ground characteristics of the slope RIM grouting target, In addition, when the grouting volume planned during the design is drilled and injected into the original ground where the waterstop is secured, there is a possibility that the original ground with the waterstop is disturbed and the effect of the waterstop is rather diminished. In order to overcome such problems, it is more suitable to first consider geological conditions and determine whether to perform optimal grouting on the original ground through on-site repair tests before performing RIM grouting. In this paper, to determine the grouting of the RIM unit, a pilot hole water pressure test was performed on the rock of the slope in the target section. The analysis shows grouting volume of 1 Lugeon or less, and the cement injection amount also shows the injection result of 1 kg/m or less. In this case, performing grouting is rather counterproductive. This result can be evaluated through a rock of which some degree of order of mass is secured, as it is a dam design standard of 1 Lugeon or less when analyzed, using the results of visual observation and geological map creation during slope cutting. Therefore, in conclusion, it is preferable to make the decision for using RIM grouting on the slope of the dam body structure, based on 1 Lugeon in a rock state, and the cement injection amount also at 1 kg/m.

A Study on the Reinforcement Effect Analysis of Aging Agricultural Reservoir using Surface Stabilizer (표층안정재를 사용한 노후 농업용 저수지의 보강효과 분석에 관한 연구)

  • Kim, Jae-Hong;Kim, You-Seong;Cho, Dae-sung
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.2
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    • pp.13-21
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    • 2020
  • In Korea, small reservoirs have been constructed for the supply of agricultural water, but most of them have been over 50 years from the year of construction. Aging agricultural reservoirs are being investigated for serious defects such as leaks and movements in slope, which are very vulnerable to safety. Accordingly, grouting methods are used to reinforce aging agricultural reservoirs in Korea. However, cement used as a grouting injection material consumes natural resources and generates a large amount of greenhouse gases during production. In addition, there is a problem that sufficient reinforcement is not made due to various factors such as the injection amount, the compounding ratio, the injection pressure, and etc. Therefore, due to these problems, the development of new materials and methods that can replace the grouting method and cement is required. In order to solve these problems, this study conducted an laboratory test on the surface stabilizer used to secure the stability of road and rail slopes. In addition, the program was analyzed and the reinforcing effect was examined when the surface stabilizer was used as reinforcement material for aging agricultural reservoir. As a result of the laboratory test, when the surface stabilizer is mixed, the increase of cohesion is possible up to 9% and there is no change in the friction angle. The results of the program analysis showed that the 1.0m reinforcement of slopes increased the factor of safety by 1.4 times, making it possible to reinforce the aging agricultural reservoir using surface stabilizers. And as a reinforcement method, it was analyzed that it is most appropriate to reinforce the slope and the bottom of slope simultaneously.

The Evaluation of Interface Shear Strength Between Geomembrane and Ceotextile (지오멤브레인/지오텍스타일의 접촉 전단강도 평가)

  • 서민우;박준범;김운영
    • Journal of the Korean Geotechnical Society
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    • v.18 no.1
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    • pp.79-89
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    • 2002
  • Various geosynthetics used as liners or protection layers are installed in the solid waste landfills. The interface shear strength between geosynthetics installed at the slope of the landfill is a very important variable for the safe design of the bottom and cover systems in the solid waste landfills. The interface shear strength between Geomembrane and Geotexile is estimated by a large direct shear test in this study, The effects of normal stress, water existing between geosynthetics and surface condition of Geomembrae, i.e. smooth or textured, were investigated. The test results show that the effect varied depending on the level of normal stress and the type of geosynthetic combinations. The shear strength was evaluated by the Mohr-Coulomb failure criterion in this research. The shear strength parameters obtained from tests considering the site specific conditions such as normal stress, dry or wet, and surface condition of geosynthetic should be applied to the design of geosynthetics installed at the slope of the landfill to construct a safe solid waste landfill.