• Title/Summary/Keyword: RAFT

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Performance of integrated vertical raft-type WEC and floating breakwater

  • Tay, Zhi Yung;Lee, Luke
    • Ocean Systems Engineering
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    • v.12 no.1
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    • pp.39-61
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    • 2022
  • Renewable energy such as wave energy has gained popularity as a means of reducing greenhouse gases. However, the high cost and lack of available sea space in some countries have hindered the deployment of wave energy converters (WEC) as alternative means of sustainable energy production. By combining WECs with infrastructures such as floating breakwaters or piers, the idea of electricity generated from WECs will be more appealing. This paper considers the integration of vertical raft-type WEC (commonly known as the vertical flap WEC) with floating breakwater as means to generate electricity and attenuate wave force in the tropical sea. An array of 25 WECs attached to a floating breakwater is considered where their performance and effect on the wave climate are presented. The effects of varying dimensions of the WEC and mooring system of the floating breakwater have on the energy generation are investigated. The integrated WECs and floating breakwater is subjected to both the regular and irregular waves in the tropical sea to assess the performance of the system. The result shows that the integrated vertical flap-floating breakwater system can generate a substantial amount of wave energy and at the same time attenuate the wave force effectively for the tropical sea when optimal dimensions of the WECs are used.

Analysis of Load Sharing Ratio of Piled Raft Foundation by Field Measurement (현장 계측을 통한 말뚝지지 전면기초의 하중분담률 분석)

  • Jeong, Sang-Seom;Lee, Jun-Hwan;Park, Jong-Jeon;Roh, Yang-Hoon;Hong, Moon-Hyun
    • Journal of the Korean Geotechnical Society
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    • v.33 no.8
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    • pp.41-52
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    • 2017
  • In this study, field measurements were investigated to analyze the load sharing ratio and behavior of piled raft foundation. The field measurements were performed for about 300 days from the start of construction. The geometry of the raft is $3.1m{\times}3.1m$, and the pre-cast and pre-bored pile is 23 m in length and 0.508 m in diameter. Based on the field measurements, the load-settlement relationship of the piled raft foundation was obtained, and the load sharing ratio of the pile was converged to 70% at ultimate loading condition. The load sharing ratio of the pile increased as the settlement increased, and this is because the surface friction of the weathered soil, which is at the lower ground, was significantly increased. Based on the results of the field measurements, load transfer curves were obtained and applied to a numerical analysis by using load transfer method.

Evaluation of Thermal Insulation and Hypothermia for Development of Life Raft (해상 구명정의 단열성능평가 및 저체온증 예측 수치해석 연구)

  • Hwang, Se-Yun;Jang, Ho-Sang;Kim, Kyung-Woo;Lee, Jang-Hyun
    • Journal of Navigation and Port Research
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    • v.39 no.6
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    • pp.485-491
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    • 2015
  • The technology review about risk of hypothermia of victim according to heat transfer characteristic of life raft and sea state can use accident correspondence of standing and sinking of ship. This study studied heat transfer characteristics required for the design of life raft and thermal insulation property analysis and evaluation methods. In addition, it is study for comprehend the risk of hypothermia and suggest analysis result that is experiment of thermal insulation property and body temperature property for decide of prediction the body temperature decline Thermal Analysis apply the finite element analysis method is comprehended the property of heat conductivity, convective effect of sea water and properties changes according to property of insulation material. it measure the heat flux with attach temperature sensor on body in order to comprehend the variation of body temperature with boarding a life raft experiment on a human body. This study validate results by comparing variation of temperature measured from experiment on a body with variation of temperature from finite element analysis model. Also, the criteria of hypothermia was discussed through result of finite element analysis.

Finite Element Vibration/Shock Analysis of Double Stage Elastic Mounting System with Viscoelastically Damped Foundation Structure (유한용소법을 이용한 점탄성 감쇠구조물이 포함된 2단 탄성마운트 시스템의 진동/충격응답 해석)

  • 정우진;류정수;배수룡;함일배
    • Journal of KSNVE
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    • v.10 no.3
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    • pp.508-516
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    • 2000
  • To study the possibility of F.E.M application to vibration and shock response of double stage elastic mounting system with complicated damped foundation structure like common-bed or raft in ships foundation structure model which has complicated damped sandwich cross-section is analyzed first. And then vibration responses experimental results and shock response of double stage elastic mounting system with complicated damped foundation structure like common-bed or raft in ships foundation structure model which adopts the above damped structure as intermediate foundation were compared. As a result it is found that F.E.M could be effectively used in analyzing the vibration and shock response of double and multi-stage elastic mounting system with complicated damped foundation structures.

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Macroalkoxyamines and macroRAFT agents based on polyethylene for the syntheses of polyolefin based polar block copolymers

  • Lopez R. Godoy;Boisson C.;D'Agosto F.;Spitz R.;Boisson F.;Gigmes D.;Bertin D.
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.377-377
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    • 2006
  • Alkoxyamine and thiocarbonyl thio end capped polyethylene (PE) chains were synthesized using a direct and simple approach consisting in reacting di(polyethylenyl)magnesium (PE-Mg-PE) chains with a range of nitroxides and disulfides of thiocarbonyl thio compounds. PE-Mg-PE compounds were prepared by a catalyzed chain growth reaction of ethylene on nbutyloctylmagnesium (BOMg) with a neodymocene complex $(C_{5}Me_{5})_{2}NdCl_{2}Li(OEt_{2})_{2}$. Complete characterizations confirm the introduction of the desired end groups. The controlled radical polymerization (NMP and RAFT) of butyl acrylate mediated by these functional polyethylenes was successful.

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A Study on the Navigation of Fishing Raft (벌선의 항해학적 고찰)

  • 정공흔
    • Journal of the Korean Institute of Navigation
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    • v.10 no.2
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    • pp.1-10
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    • 1986
  • For the purpose of estimation of navigational method and ability about fishing raft, we have practical navigation of her from Chujado on Oct, 7 to Maryang-ri , Kangjin-kun, Jeonranman-do on Oct.10. The results obtained are as follow : 1. Ancient navigation of her is thought to over to an isolated island in the vicinity with a good informations and experiences. 2. Speed of her in outward voyage is 1.34 knots, but is varied with structure and shape of her and ability of fishing raftman. 3. The lee way(U) of her with sail of hight 2.5m and breadth about 1.2m according to windspeed(W) is U=$0.038{\times}W$ 4. We could estimate to take only three days to go over from Chujado to Maryang-ri, Kangjin-kun. Jeonranam-do by her with sail, and make a voyage total 55 miles for thirty-four hours and ten minutes i, e, mean speed is 1.6knots resulty.

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