• Title/Summary/Keyword: high bog

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Characteristics of the Rainfall-Runoff and Groundwater Level Change at Milbot Bog located in Mt.Cheonseong (천성산 밀밭늪의 강우 유출 및 지하수위 변동 특성)

  • Jung, Yu-Gyeong;Lee, Sang-Won;Lee, Heon-Ho
    • Journal of Korean Society of Forest Science
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    • v.99 no.4
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    • pp.559-567
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    • 2010
  • This study was conducted to investigate the hydrological characteristics of groundwater level change and rainfall hydrological runoff processes caused by tunnel construction at Milbot bog located in Mt. Cheonseong. Data were collected from July 2004 to May 2008. The results were summarized as follows: The occurrence time of the direct runoff caused by unit rainfall at the Milbot bog were tended to be slower than those at general mountainous basin. Also, runoff did not sensitively respond to amount of rainfall at the most of the long and short term hydrograph. The annual runoff rates from 2004 to 2008 were 0.26, 0.13, 0.16, 0.25 and 0.27, respectively, slightly increased after 2005 regardless of the tunnel construction. Thus, the function of Milbot bog will be weakened, and it supposed to be changed to land in the future because of increasing annual runoff. The annual runoff rate for 4 years was 0.19, which is greatly lower than that of general mountainous basin. The recession coefficient of the direct runoff in short term hydrograph was ranged to 0.89~0.97, which is much larger than that of the general mountainous basin, 0.2~0.8. The recession coefficient of base flow ranged from 0.93 to 0.99, which are similar to general mountainous watershed's values. Groundwater level of Milbot bog increased or decreased in proportion to rainfall intensity, and in the descending time after the groundwater level was reached at peak point, it tends to be decreased very slowly. Also, groundwater level increased or decreased maintaining relatively high value after precedent rainfall. Groundwater level was highest during summer with heavy rainfall, but was lowest during winter. Average groundwater levels decreased annually from 2004 to 2008, -8.48 cm, -14.60 cm, -20.46 cm, -20.11 cm, -28.59 cm, respectively. Therefore, it seems that the Milbot bog is becoming dry and losing its function as a bog.

Optimal Conditions for the Wet Funnel Extraction of Enchytraeidae from Peat Soils of Moorlands in England (영국 고원지대(Moorland)의 이탄 토양에서 애지렁이 추출을 위한 수분깔때기의 최적조건)

  • ;H.I.J.Black;P.Ineson
    • The Korean Journal of Soil Zoology
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    • v.5 no.2
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    • pp.63-70
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    • 2000
  • The effect of combinations of temperature, water column height and extraction time onthe efficiency of wet funnel extraction methods for enumerating Enchytraeids in a blanket bog peat soil from Moor House, Cumbria, England were investigated. The optimal conditions for extracting enchytraeids from this study were found to be a water surface temperature of 35$^{\circ}C$, with an extraction time of 6 hours, regardless of initial water temperature and water level in the extraction funnel. The original O'Connor method (40-45$^{\circ}C$ for 3 hours extraction and gradually increasing heating) yielding a high variation in the extraction efficiency, largely due to the comparatively higher temperature and shorter extraction time than this method. Attempts to extract without heat over longer periods showed very low extraction efficiencies for this highly organic blanket bog soil when compared with any of the heating wet funnel methods.

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Characteristic analysis and condenser design of gas helium circulation system for zero-boil-off storage tank

  • Jangdon Kim;Youngjun Choi;Keuntae Lee;Jiho Park;Dongmin Kim;Seokho Kim
    • Progress in Superconductivity and Cryogenics
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    • v.25 no.4
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    • pp.65-69
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    • 2023
  • Hydrogen is an eco-friendly energy source and is being actively researched in various fields around the world, including mobility and aerospace. In order to effectively utilize hydrogen energy, it should be used in a liquid state with high energy storage density, but when hydrogen is stored in a liquid state, BOG (boil-off gas) is generated due to the temperature difference with the atmosphere. This should be re-condensed when considering storage efficiency and economy. In particular, large-capacity liquid hydrogen storage tank is required a gaseous helium circulation cooling system that cools by circulating cryogenic refrigerant due to the increase in heat intrusion from external air as the heat transfer area increases and the wide distribution of the gas layer inside the tank. In order to effectively apply the system, thermo-hydraulic analysis through process analysis is required. In this study, the condenser design and system characteristics of a gaseous helium circulation cooling system for BOG recondensation of a liquefied hydrogen storage tank were compared.

High Performance Fiber Reinforced Cement Composites in Construction Field (건설분야의 섬유강화 시멘트 복합 신재료)

  • Hong, Geon-Ho;Kim, Ki-Soo;Han, Bog-Kyu
    • Composites Research
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    • v.19 no.1
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    • pp.43-48
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    • 2006
  • High performance fiber reinforced cement composites have better performances than traditional cement based materials, therefore, have been expected as new construction applications such as the materials for construction & bridge structure, repair and rehabilitation applications, anti-collapse applications, anti-noise applications etc. However, they have lots of the problems such as material design, fabrication method and structural analysis. Also, the most serious problems of High performance fiber reinforced cement composites have been expensive initial cost, lack of long-term exposure data. As a result, it is needed that the efforts for lowering the initial cost and accumulation of long-term exposure. There has been hardly assessment results of life cycle cost for HPFRCC in construction field, but some papers showed that total life cycle cost could be profitable if the initial cost could be reduced.

Dynamic Analysis of a 3-Axis Ultra-Slim Actuator for Optical Disc Drives (광디스크 드라이브용 3축 초박형 액추에이터의 동특성 분석)

  • Kim Se-Won;Cho Tae-Min;Lee Ju-Hyung;Jin Kyoung-Bog;Rim Kyung-Hwa
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.4 s.235
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    • pp.624-631
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    • 2005
  • A note-book PC has become thinner in recent years, which requires the optical disc drives with small height and high memory capacity. Therefore the actuator of optical disc drives must be thinner and have disc tilt compensation function for high density memory. In this paper, the actuator with hybrid type is investigated for 3-axis ultra-slim actuator. A 3-axis ultra-slim actuator is designed by using the modal analysis of the actuator and the electromagnetic analysis of magnetic circuit to achieve dynamic characteristics. Also, magnetic force between tilt magnet and tilt yoke is investigated to and the influence on the DC sensitivity in the focus and track directions.

Study on the Wear Characteristics of the High Strength Ductile Irons (고강도 구상흑연구철의 내마모성에 미치는 기지조직의 영향에 관한 연구)

  • Kim, Bog-Suk;Choi, Chang-Ock
    • Journal of Korea Foundry Society
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    • v.9 no.3
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    • pp.237-246
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    • 1989
  • This study has been carried out to investigate the difference of rolling life and rolling wear characteristics for various high strength ductile iron castings under unlubricative dry rolling condition by Amsler type wear test with 9.09% sliding ratio. The tensile strength of the castings have been obtained 80, 90 and $100kg.f/mm^2$ as cast-state with pearlitic, bainitic and martensitic matrix structures alloyed with Mo, Cu and Ni. It has been found that the amount of rolling wear is decreased when the tensile strength and hardnees of the castings are increased. The amount of rolling wear is increased, when the maximum compressive stress are increased. The maximum weight loss ratio of rolling wear of the castings are same at the 70000 numbers of revolution with out the maximum compressive stress.

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Experimental Study on the Partial Oxidation Reforming of CH4/O2 Mixture in Two-Section Porous Media at High Pressure Conditions (고압 분위기에서 CH4/O2 혼합기의 2단 다공체 내 부분산화 개질에 관한 실험적 연구)

  • Guahk, Young Tae;Lee, Dae Keun;Kim, Seung Gon;Ko, Chang-Bog;Park, Jong-Ho
    • 한국연소학회:학술대회논문집
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    • 2015.12a
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    • pp.73-74
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    • 2015
  • Synthesis gas such as hydrogen and carbon monoxide was produced from $CH_4/oxygen$ mixture using insulated pressurized porous media combustor. Experimentally, two cylindrical SiC foams with the different pore density were piled up in a quartz tube and fully premixed mixture was supplied in the axial direction. After stabilizing fuel-rich flame at the interface of the two foams at several pressure conditions, mole fractions of synthesis gases were measured by gas chromatography. Heat recirculation through the inner foam structure could extend the flow velocity of stable region over the laminar burning velocity. As the pressure increased, the rich flammability limit, $H_2/CO$ ratio, and module M increased.

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