• 제목/요약/키워드: Green Water

검색결과 2,514건 처리시간 0.026초

부유식 OWC 챔버의 파중 운동해석 (A Study on the Floating OWC Chamber Motion in Waves)

  • 홍도천;홍사영
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2002년도 춘계학술대회 논문집
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    • pp.191-197
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    • 2002
  • The motion of a floating OWC chamber in waves is studied taking account of fluctuating.air pressure in the air chamber. An atmospheric pressure drop occurs across the upper opening of the chamber which causes not only hydrodynamic but also pneumatic added mass and damping forces to the floating chamber. A velocity potential in the water due to the free surface oscillating pressure patch is added to the conventional radiation-diffraction potential problem. The potential problem inside the chamber is formulated by making use of the Green integral equation associated with the Rankine Green function while the outer problem with the Kelvin Green function. The two integral equations are solved simultaneously by making use of a matching boundary condition at the lower opening of the chamber to the outer water region. The chamber motion in the frequency domain is calculated for various values of parameters related to the atmospheric pressure drop. The present methods can also be used for the analysis of air-cushion vehicle motion as well as for the design oj a floating owe wave energy absorber.

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그린리모델링 활성화를 위한 비전문가용 에너지 소비량 산정 프로그램 개발연구 (A Study on the Development of Energy Simulation Program for Non-specialist to Enhance Green Remodeling)

  • 방선규;유정현;김두환
    • 대한건축학회논문집:구조계
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    • 제34권11호
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    • pp.55-62
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    • 2018
  • To receive financial support for the Green Remodeling, applicants must submit an energy simulation report. However, many of the applicants are not green remodeling specialist and energy simulation services are too expensive for them. For this reason, this study was to develop an energy simulation program to enhance green remodeling for the non-specialist such as housewives. Firstly, to enhance understanding and accessibility improvement energy simulation, simulation process was designed four steps and reducing input data. Specifically, input data was reduced by categorizing the following for the area, plan type, hot water load, electricity load, statistical inference. And then, to accurately verify the calculation result, the heat and hot water demand were derived and compared with ECO2 and Energy # program. Lastly, the calculation shows that there is a difference of 4% for the heat load and 15% to 33% for the hot water load respectively.

기후변화적응형 도시림 조성을 위한 i-Tree Canopy 기반 의사결정지원 방안 (i-Tree Canopy-based Decision Support Method for Establishing Climate Change Adaptive Urban Forests)

  • 김태한;이재영;송창길;오지은
    • 반도체디스플레이기술학회지
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    • 제23권1호
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    • pp.12-18
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    • 2024
  • The accelerated pace of climate crisis due to continuous industrialization and greenhouse gas emissions necessitates sustainable solutions that simultaneously address mitigation and adaptation to climate change. Naturebased Solutions (NbS) have gained prominence as viable approaches, with Green Infrastructure being a representative NbS. Green Infrastructure involves securing green spaces within urban areas, providing diverse climate adaptation functions such as removal of various air pollutants, carbon sequestration, and isolation. The proliferation of Green Infrastructure is influenced by the quantification of improvement effects related to various projects. To support decision-making by assessing the climate vulnerability of Green Infrastructure, the U.S. Department of Agriculture (USDA) has developed i-Tree Tools. This study proposes a comprehensive evaluation approach for climate change adaptation types by quantifying the climate adaptation performance of urban Green Infrastructure. Using i-Tree Canopy, the analysis focuses on five urban green spaces covering more than 30 hectares, considering the tree ratio relative to the total area. The evaluation encompasses aspects of thermal environment, aquatic environment, and atmospheric environment to assess the overall eco-friendliness in terms of climate change adaptation. The results indicate that an increase in the tree ratio correlates with improved eco-friendliness in terms of thermal, aquatic, and atmospheric environments. In particular, it is necessary to prioritize consideration of the water environment sector in order to realize climate change adaptive green infrastructure, such as increasing green space in urban areas, as it has been confirmed that four out of five target sites are specialized in improving the water environment.

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규칙파 중 갑판침입수 충격하중 감소를 위한 선수형상 설계 (Design of Bow Shape to Decrease Green Water Impact Loading in Regular Waves)

  • 하윤진;이영길;정광열
    • 한국해양공학회지
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    • 제26권4호
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    • pp.15-22
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    • 2012
  • In this research, the relationship between the bow shape and green water phenomenon on the bow deck of an FPSO was studied using an experimental method. A 140,000 DWT FPSO was used as the objective hull form in the present research. The incident waves were regular types. The heights were 1.0 and 1.5 times the freeboard, and the length was equal in size to LBP. The wave heights and pressures on the deck were measured in experiments. Model tests were performed to determine the effects of bow flare angles, bow shapes, and a forecastle deck. The free heave and pitch conditions were applied to the models in these experiments. From the results of the model tests, an optimized bow shape was designed, which was found to decrease the green water impact loading. The results of this research could be used as fundamental data in the design of a bow shape.

강우시 습윤에 의한 불포화 풍화토의 사면 안정 해석 연구 (A Study of Stability Analysis on Unsaturated Weathered Slopes Based on Rainfall-induced Wetting)

  • 김재홍;박성완;정상섭;유지형
    • 한국지반공학회논문집
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    • 제18권2호
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    • pp.123-136
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    • 2002
  • 강우시 발생하는 여러 사면의 얕은 파괴는 지표로 침투하는 강우에 의한 포화깊이 증가에 의해 발생한다. 본 연구에서는 불포화사면 해석을 위하여 국내의 전형적인 표토층을 구성하는 화강풍화토를 3가지(SW, SP, SM)로 분류하여 함수특성곡선을 각각 구하고 그에 따른 함수특성곡선의 방정식을 추정하였으며, 기존에 사용되고 있는 Green & Ampt의 포화깊이 추정식과 수치해석 결과를 비교.분석함으로써 추정식의 사용범위에 대한 제한성을 파악하였다. 또한, 강우에 의한 사면의 포화깊이가 사면의 안정성에 미치는 영향을 파악하고 화강풍화토의 함수특성곡선을 이용하여 불포화사면의 강도정수를 추정하여 계산된 불포화지반의 해석이 기존의 포화사면의 해석에 비하여 보다 정확한 결과임을 알 수 있었다.

Nonlinear effect on wave loads of large ships in time domain

  • Kim, Mun-Sung;Park, Jong-Jin;Kim, Byung-Woo;Eom, Jae-Kwang
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제3권1호
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    • pp.95-104
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    • 2011
  • As sea state harsher in the ocean space, more large motion and wave loads occurs on ships hull by non-linear phenomena. To consider nonlinear effect on ships hull in the structural design verification, the direct calculation method with numerical approach is used rather than rule values for the reliable accuracy. In this paper, the non-linear wave loads analysis in time domain is performed by using a Rankine Panel Method together with numerical schemes. Linear calculations have been carried out based on DNV CSA-2 notation to generate the motion responses and wave loads of large ships. By short and long term analysis, the design wave amplitudes are selected for the nonlinear analysis. The maximum wave induced bending moment in hogging and sagging conditions are calculated in the nonlinear analysis. Also, the green water effect on the wave induced vertical bending moment was investigated. The results show the vertical bending moments are more influenced by green water in sagging condition than in hogging condition due to green water loading.

클링커 제조 조건에 따른 수용성 6가 크롬 용출 특성 (Leaching Properties of Water-Soluble Hexavalent Chromium by Manufacturing Condition of Cement Clinker)

  • 이종규;추용식;송훈
    • 한국재료학회지
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    • 제21권12호
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    • pp.679-684
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    • 2011
  • One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The purpose of the present study was to investigate leaching properties of water-soluble hexavalent chromium by different manufacturing conditions of cement clinker. Raw materials were prepared to add different $SiO_2$, $Al_2O_3$ and $Fe_2O_3$ sources. After the raw materials, such as limestone, sand and clay, iron ore was pulverized and mixed, and the raw meal was burnt at $1450^{\circ}C$ in a furnace with an oxidizing atmosphere. Leaching of soluble hexavalent chromium showed a tendency to decrease with an increasing LSF and IM. However, leaching of soluble hexavalent chromium increased with an increasing S.M. Alkali contents of iron source minerals is closely related to the leaching properties of soluble hexavalent chromium. Green sludge has the highest content of alkali added; leaching of water-soluble hexavalent chromium was mostly high. In order to reduce the water-soluble hexavalent chromium in cement, reducing the alkali content in raw materials is important.

미래 그린 해수담수화 기술 (Future green seawater desalination technologies)

  • 김정빈;홍승관
    • 상하수도학회지
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    • 제34권6호
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    • pp.403-410
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    • 2020
  • The difficulty of securing freshwater sources is increasing with global climate change. On the other hand, seawater is less affected by climate change and regarded as a stable water source. For utilizing seawater as freshwater, seawater desalination technologies should be employed to reduce the concentration of salts. However, current desalination technologies might accelerate climate change and create problems for the ecosystem. The desalination technologies consume higher energy than conventional water treatment technologies, increase carbon footprint with high electricity use, and discharge high salinity of concentrate to the ocean. Thus, it is critical to developing green desalination technologies for sustainable desalination in the era of climate change. The energy consumption of desalination can be lowered by minimizing pump irreversibility, reducing feed salinity, and harvesting osmotic energy. Also, the carbon footprint can be reduced by employing renewable energy sources to the desalination system. Furthermore, the volume of concentrate discharge can be minimized by recovering valuable minerals from high-salinity concentrate. The future green seawater desalination can be achieved by the advancement of desalination technologies, the employment of renewable energy, and the utilization of concentrate.

녹지분포에 따른 기온변화 (Air Temperature Variation by Effect of Green Space Distribution)

  • 윤용한
    • 한국환경복원기술학회지
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    • 제5권2호
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    • pp.47-52
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    • 2002
  • In this study, in order to find out relationship of green space distribution and lower air temperature effect, observed air temperature distribution in and out green space in the cloudy. On basis of the result, we are analyzed relationship of air temperature distribution in and out green space, of green space distribution and air temperature of, lower air temperature effect and the urban in between the green space by using regression analysis. According to the result, the higher temperature zone formed around urban, and the lower temperature zone was similar to shape of green space. In case of the green space, higher temperature zone is formed around paved surface and barren ground, lower temperature zone is done forest and water area. To compare air temperature of windward and leeward around green space, the windward formed the lower temperature zone and although the wind direction is not the leeward to the green space, air temperature formed lower temperature zone to the urban in between the green space.