• Title/Summary/Keyword: Break-In

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Finding the optimum shape of the energy dissipator to minimize the impact force due to the dam break flow

  • Asrini Chrysanti;Sangyoung Son
    • Ocean Systems Engineering
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    • v.14 no.2
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    • pp.157-169
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    • 2024
  • The sudden release of water from a dam failure can trigger bores on a flat surface and exert substantial impact forces on structures. This flow poses a high-risk flood hazard to downstream urban areas, making it imperative to study its impact on structures and devise effective energy dissipators to mitigate its force. In this study, a combination of Genetic Algorithm optimization and numerical modeling is employed to identify the optimal energy dissipator. The analysis reveals that a round arc-shaped structure proves most effective, followed by a triangular shape. These shapes offer wide adaptability in terms of structure dimensions. Structures with higher elevation, especially those with round or triangular shapes, demonstrate superior energy dissipation capabilities. Conversely, square-shaped structures necessitate minimal height to minimize impact forces. The optimal width for dissipating energy is found to be 0.9 meters, allowing for effective wave run-up and propagation. Furthermore, the force exerted on structures increases with higher initial water levels, but diminishes with distance from the dam, highlighting the importance of placement in mitigating impact forces.

Effect of the same recovery with individual exercise intensity on the variation of Cortisol and Catecholamine in their blood (운동 강도별 동일 회복이 혈중 Cortisol과 Catecholamine 호르몬 변화에 미치는 영향)

  • Shin, Won;Choi, Won-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.5
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    • pp.2232-2239
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    • 2012
  • This study set out to investigate the effects of the same amount of resting(30 minutes) after $VO_2max$ 20%, 40%, and 60% exercise on the variation of cortisol and catecholamine, serum stress hormones. The research efforts led to the following conclusions: First, there were no significant differences in serum cortisol concentration between the $VO_2max$ 20% group and the $VO_2max$ 40% group, but there were some significant differences in the significance level of p=.002 in the $VO_2max$ 60% group. Second, there were no significant differences in serum catecholamine concentration between the $VO_2max$ 20% group and the $VO_2max$ 40% group, but there were some significant differences in the significance level of p=.001 in the $VO_2max$ 60% group. Third, no significant differences were found in the changing rates of serum cortisol concentration between right after exercise and during break among different levels of exercise intensity according to measuring time. Fourth, there were significant differences in the changing rates of serum catecholamine concentration in the significance level of p=.000 right after exercise and in the significance level of p=.034 during break In short, there were significant differences only in the $VO_2max$ 60% group according to exercise intensity when the different groups took the same amount of break after exercise. The $VO_2max$ 60% group was also the only group that showed significant differences in the changing rates of cortisol and catecholamine. In conclusion, taking a break after exercise can generate huge effects only when the exercise intensity level is moderate or higher. That is, taking a break will have no significant effects when the exercise intensity level is lower than moderate.

Review on the Triassic Post-collisional Magmatism in the Qinling Collision Belt (친링 충돌대의 트라이아스기 충돌 후 화성작용에 대한 리뷰)

  • Oh, Chang Whan;Lee, Byung Choon;Yi, Sang-Bong;Zhang, Cheng Li
    • The Journal of the Petrological Society of Korea
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    • v.23 no.4
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    • pp.293-309
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    • 2014
  • The Qinling-Dabie-Sulu-Hongseong-Odesan collision belt was formed by the collision between the North China and South China Cratons during late Permian to Triassic. During the collision, Triassic post-collision igneous rocks regionally intruded in the Qinling and the Hongseong-Odesan collision belts which represent the western and eastern ends of the collision belt, respectively. However, no and minor Triassic post-collision igneous activities occur in the Dabie and Sulu belts respectively. The peak metamorphic pressure conditions along the Qinling-Dabie-Sulu-Hongseong-Odesan belt indicate that the slab break-off occurred at the depth of ultra-high pressure (UHP) metamorphic condition in the Dabie and Sulu belts and at the depths of high pressure (HP) or high pressure granulite (HPG) metamorphic condition in the Qinling and Hongseong-Odesan belts. In the Dabie and Sulu belts the heat supply from the asthenospheric mantle through the gab formed by slab break-off could not cause an extensive melting in the lower continental crust and lithospheric mantle directly below it due to the very deep depth of slab break-off. On the other hand, in the Qinling and Hongseong-Odesan belts, shallower slab break-off caused the emplacement of regional post collision igneous rocks. The post-collision igneous rocks occur in the area to the north of the Mianlu Suture zone in the western Qinling belt and crop out continuously eastwards into the areas to the north of the Shangdan Suture zone in the eastern Qinling belt through the areas within the South Qinling block. This distribution pattern of post collision igneous rocks suggests that the Triassic collision belt in the Mianleu Suture zone may be extended into the Shangdan Suture zone after passing through the South Qinling block instead into the boundary between the South Qinling block and the South China Craton.

INSTALLATION PARAMETERS EFFECTING ON THE WIND PROOF OF A COASTAL FOREST (해안림의 방풍 효과에 영향을 미치는 설치 파라미터 분석)

  • Shin, J.H.;Chang, S.M.;Park, K.H.;Youn, H.J.
    • Journal of computational fluids engineering
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    • v.20 no.2
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    • pp.52-60
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    • 2015
  • The objective of this research lies in the effect of installation parameters influencing on the wind proof performance of the coastal forest for damage prevention. The dissipation ratio of incident wind power is developed as an assessment index to make a lumped parameter study possible. From the real field data of East, West, and South Sea bounded on the Korean peninsula, single and double storied forests were modeled in three-dimensional shape with computer aided design, and so was done the artificial structures such as wind break, sand accumulating fence, and sand dune, etc With a commercial code ANSYS-CFX, the computational result from the comparison of dissipation ratio between single and double storied forest shows the effect of composition, and also the installation effect is investigated for artificial structures with optimal dimension of distance.