• Title/Summary/Keyword: Relative vertical velocity

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Detailed Deterioration Evaluation and Analysis of Conservation Environment for the Seosanmaaesamjonbulsang (Rock-carved Triad Buddha in Seosan), Korea (서산마애삼존불상의 정밀 손상도 평가와 보존환경 분석)

  • Lee, Sun-Myung;Lee, Chan-Hee;Kim, Ji-Young
    • Journal of Conservation Science
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    • v.26 no.3
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    • pp.277-294
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    • 2010
  • The Seosanmaaesamjonbulsang (National Treasure No. 84) consists of light gray and coarse to mediumgrained biotite granite with partly developed pegmatite and quartz vein. The host rock is divided into dozens of rock blocks with various shape along irregular discontinuity plane. The evaluation results of discontinuity systems reveal that the host rock were exposed to instable sloping environments. Results of deterioration diagnosis show that the degree of damage has been made worse by physical weathering and surface discoloration laying stress on part that vertical and horizontal joints are massed. Generally, deterioration rate of the triad Buddha surface cover with 42.7%, however, the rate of physical weathering and surface discoloration are subdivided to 9.6% and 33.1%, respectively. Ultrasonic measurements indicate that the triad Buddha was reached highly weathered grade in general. And the rock material was weaken to show low velocity zone of 1,000m/s along irregular joint systems. Indoor and outdoor mean relative humidity of the shelter was recorded more than 70% during every season, and high frequency appears in high relative humidity range over 95%. Such environments seem to have produced dew condensation on the rock surface with rainfall and supply water, promoted physical, chemical and biological weathering along crack and joint, resulting in high permeation of water and percentage of water content. Therefore, it is judged that for scientific conservation of the triad Buddha it needs environment control through persistent preservation environment monitoring including water problem.

Improving of the Fishing Gear and Development of the Automatic Operation System in the Anchovy Boat Seine- II Analysis of escaping behaviour of anchovy in relation to underwater light and towing flow velocity (기선권현망어업의 어구개량과 자동화조업시스템 개발- II 수중광 및 예망유속과 멸치의 도피반응 행동 분석)

  • 김용해;장충식;안영수;김형석
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.37 no.2
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    • pp.78-84
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    • 2001
  • Escape behaviour of the anchovy (Engralius japonica, total length 4-7cm) at the inside wing net and bag net in the anchovy boat seine was observed by underwater video camera in order to clarify the relationship between visual stimulus of the gear or relative water flow inside gear and reacting behaviour. The vertical attenuation coefficient of underwater illuminance in the offshore of Keoje island and Tongyoung was ranged from 0.24 to 1.03 and it could be affect visual range and visual contrast of the fishing gear. The relative water flow at the joint part between inside wing and bagnet while towing was 1.5 times higher than at the middle part of inside wing or fore part of bag net, but it was estimated under than maximum swimming speed of 4-7 cm anchovy. The mean escaping number of anchovy from end part of inside wing of 30 cm mesh to out side for a minute within visual range of video camera was 455 and anchovy swimming forward from bag net through flapper was 308. These results revealed anchovy could escape as voluntary response in spite of higher visual stimulus or higher water flow.

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Impact Assessment on the Change of Thermal Environment, According to the Hydraulic Characteristic Urban Regeneration Stream: Cheonggyecheon Case Study (도심재생하천 내 수리적 특성이 열환경 변화에 미치는 영향 평가: 청계천을 대상으로)

  • Kim, Jeong-Ho;Lee, Ju-Seung;Yoon, Yong-Han
    • Journal of Environmental Policy
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    • v.14 no.2
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    • pp.3-25
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    • 2015
  • Our goal is to verify how changes in water's hydraulic characteristics after urban regeneration stream can affect any possible transformation of its thermal environment. To that end, we analyzed changes in numerous physical characteristics the subject stream along with the meteorological factors and thermal environment affected by it. Cheonggyecheon was selected as our subject as it is a great example of successful urban regeneration stream. As for physical characteristics, we allocated Type I (0.0%) and Type II (20.2%), depending on the green coverage ratio. As for numerical characteristics, at the point of Ba in which the riffle ends, the water temperature fell by $0.2^{\circ}C$ and the flow increased from 0.7m/s to 0.9 m/s with the dissolved oxygen increasing from 0.5mg/L to 0.6mg/L. As for meteorological factors surrounding the subject stream, the temperature dropped from $1.1^{\circ}C$ to $1.4^{\circ}C$ on average and relative humidity increased from 6.6% to 8.7%. Furthermore, there was an irregular change in wind velocity. According to the result of the Wet Bulb Globe Temperature (WBGT), the change in the values of Type I and II inside and on the surface of the subject stream was negligible. The downstream temperature in Type I fell from $0.3^{\circ}C$ to $0.6^{\circ}C$ and by $0.8^{\circ}C$ in Type II. As for vertical cooling effect, the change of water level was 120cm in Type I and 140cm in Type II. As for horizontal cooling effects, the value of Type I was increased from the point of Ba where the riffle ends and the value of Type II was on a steady decline.

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Fundamental Experiment on the Flow Characteristics inside the Exhaust Duct of Cone Calorimeter (콘 칼로리미터의 배기 덕트 내부 유동 특성 기초 실험)

  • Shin, Yeon Je;You, Woo Jun
    • Fire Science and Engineering
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    • v.33 no.4
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    • pp.35-40
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    • 2019
  • In this study, the mass flow rate of the heat release rate equation, which is the major factor of the oxygen consumption method, was analyzed for the fundamental investigation of the cone-calorimeter (5 m length and 0.3 m diameter). The shapes of a completely empty inside, 3 mm pore diameter mesh and pore diameter 10 mm honeycomb with 0.76 porosity were constructed using the cone-calorimeter. To calculate the mass flow rate, four bi-directional probes and thermocouples were installed in a uniform position in the vertical direction of flow. The velocity gradient and flow perturbation were measured from the increase in Reynolds number. As the flow capacity increased, the speed gradient increased in all three shapes relative to the turbulence intensity. In addition, the deviation of extended uncertainty to the mass flow was completely low in the order of empty space, mesh (dp = 3 mm) and honeycomb (dp = 10 mm and 𝜖 = 0.76) at the 95% confidence level. The results can be used in designs to improve the flow stability of the cone calorimeter.