• Title/Summary/Keyword: Surface Vessel

검색결과 507건 처리시간 0.028초

한국산(韓國産) 참나무과(科) 수종(樹種) 도관구조(道管構造)에 관(關)한 연구(硏究)(II) -도관벽(導管壁)의 수식구조(修飾構造)- (A Study on the Vessel Structure of Fagaceae Species in Korea (II) -Micromorphology of Vessel Wall Sculpture-)

  • 이성재;이원용
    • Journal of Forest and Environmental Science
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    • 제8권1호
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    • pp.51-66
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    • 1992
  • This study was carried out to investigate the micromorphology of vessel wall sculpture such as shape of perforation plate, perforation rim, steepness of perforation plate, occurrence of vestured pit, warty layer and ray-vessel pitting on 13 species of Fagaceae in Korea. The results were summarized as follows ; 1. In the species examined, all sample species except Fagus crenata var. multinervis have simple perforation plate. But Fagus crenata var. multinervis has simple and scalariform perforation plate (it was called to combination perforation plate) in a tree stem. 2. The shapes of perforation rim could be classified into five types; Type A without tail, Type B with small tail on both sides, Type C with long tail on both sides, Type D with tail only one side and Type E with the very short interval between perforations. Among five types, Type Band C have higer frequency of distribution than the others. 3. The steepness of perforation plate measured was about 20 degree on pore zone and 43 degree on outside parts of pore zone. 4. Species with vestured pit were Q. aliena, Q, dentata, Q. variabilis, Fagus crenata var. multinervis, Castanopsis cuspidata var sieboldii, Q. acuta, Q. stenophylla, and Q. glauca. But the extent of vesturing was very slight and vestured pits were observed mainly in ray-vessel pit of some vessel elements. 5. Species with warty layer on the inner surface wall of all vessel elements were Q. acuta, Q. stenophylla, Q. glauca, Fagus crenata var. multinervis and species with warty layer of some vessel elements were Q. aliena, Q, dentata, Q. variabilis, Castanopsis cuspidata var. sieboldii. 6. Species with palisade ray-vessel pit were Q. acuta, Q. stenophylla, Q. glauca, Castanea crenata, Castanea bungeana, Q. aliena, Q. serrata, Q. mongolica, and species with scalariform ray-vessel pit was Fagus crenata var. multinervis and species with oval ray-vessel pit were Q, dentata, Castanopsis cuspidata var sieboldii.

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수용액에서 입상활성탄에 의한 페놀류의 제거 (Removal of Phenols by Granular Activated Carbon in Aqueous Solution)

  • 권성헌;강원석
    • 한국환경과학회지
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    • 제7권4호
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    • pp.541-548
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    • 1998
  • Aqueous phase adsorption of phenols by granular activated carbon was studied in a batch adsorption vessel. Adsorption Isotherms of phenol(Ph), p-chlorophenol(PCP) and p-nitrophenol (PNP) from aqueous solution on granular activated carbon have been obtained. The experimental data were analyzed by the surface and pore diffusion models. Both models could be applied to predict the adsorption phenomena. However, the pore diffusion model was slightly better than the surface diffusion model In representing the experimental data for the initial concentration changes. Therefore, the pore diffusion model was used to predict the change of operating variables such as the agitation speed and Particle size of adsorbent which have influence on the film resistance and intraparticle diffusion.

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멸치가공을 위한 태양열 온수기 개발 (A development of solar hot water system for anchovy proceeding)

  • 공태우;지명국;이용훈;정한식;정효민
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집D
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    • pp.671-676
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    • 2001
  • This study are development results of solar hot water system for anchovy proceeding. The heat amounts of boiling vessel are calculated 292.66W at forward and backward direction, and surface direction are calculated 373.14W. The polyenoic rate of anchovy are measured lower as high temperature, but monoenoic and polyacid are higher. Then the others. The maximum radiation of anchovy fishing grounds are shown $350kcal/m^2h$ at pm. 13:00, Chungdo in CHINA. Distributions of Velocity and temperature in boiling vessel are calculation. Solar collector and boiling vessel for anchovy proceeding ship are developed to automatic control system.

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Impregnation of Castanea creanata Wood by Hydrophobic Oil

  • Ahmed, Sheikh Ali;Lee, Kyoung-Min;Chun, Su-Kyoung
    • 한국가구학회지
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    • 제19권1호
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    • pp.91-96
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    • 2008
  • This paper investigates the penetration of essential oil into radial and longitudinal directions of Castanea crenata. Present study was performed to know the essential oil penetration depth in radial and longitudinal direction of Castanea crenata. Essential oil penetration depth was found higher in longitudinal direction than in radial direction and it was about 53 times high at 15.0 second of penetration. In early wood, fiber conducted oil more than that of large vessel. In heartwood, fiber had played an important role for the conduction of oil. But in sapwood, small vessel conducted oil deeper than wood fiber, which was also significantly different from large. On the other hand, large vessel in heartwood had statistically lower penetration depth than that of fiber and small vessel. At the beginning of penetration the speed was high and gradually decreased in course of time.

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Automatic Berthing Finite-time Control Considering Transmission Load Reduction

  • Liu Yang;Im Nam-kyun
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2022년도 추계학술대회
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    • pp.168-169
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    • 2022
  • In this study, we investigates the auto-berthing problem for the underactuated surface vessel in the presence of constraints of dynamic uncertainties, finite time, transmission load, and environmental disturbance. A novel control scheme is proposed by fusing the finite time control technology and the event-triggered input algorithm. In the algorithm, differential homeomorphism coordinate the transformation is used to solve the problem of underactuation. Then, we apply the finite time technology and event triggered to save the time of the berthing vessel and relieve transmission burden between the controller and the vessel respectively. Moreover, a radial basis function network is used to approximate unknown nonlinear functions, and minimum learning parameters are introduced to lessen the computational complexity. A sufficient effort has been made to verify the stability of the closed-loop system based on the Lyapunov stability theory. Finally, simulation results display the effectiveness of the proposed scheme.

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Design of Quorum Quenching Microbial Vessel to Enhance Cell Viability for Biofouling Control in Membrane Bioreactor

  • Cheong, Won-Suk;Kim, Sang-Ryoung;Oh, Hyun-Suk;Lee, Sang H.;Yeon, Kyung-Min;Lee, Chung-Hak;Lee, Jung-Kee
    • Journal of Microbiology and Biotechnology
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    • 제24권1호
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    • pp.97-105
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    • 2014
  • Quorum quenching (QQ) with a microbial vessel has recently been reported as an economically feasible biofouling control platform in a membrane bioreactor (MBR) for wastewater treatment. In this study, a quorum quenching MBR with a ceramic microbial vessel (CMV) was designed to overcome the extremely low F/M ratio inside a microbial vessel. The CMV was prepared with a monolithic ceramic microporous membrane and AHL-degrading QQ bacteria, Pseudomonas sp. 1A1. The "inner flow feeding mode" was introduced, under which fresh feed was supplied to the MBR only through the center lumen in the CMV. The inner flow feeding mode facilitated nutrient transport to QQ bacteria in the CMV and thus enabled relatively long-term maintenance of cell viability. The quorum quenching effect of the CMV on controlling membrane biofouling in the MBR was more pronounced with the inner flow feeding mode, which was identified by the slower increase in the transmembrane pressure as well as by the visual observation of a biocake that formed on the used membrane surface. In the QQ MBR with the CMV, the concentrations of extracellular polymeric substances were substantially decreased in the biocake on the membrane surface compared with those in the conventional MBR. The CMV also showed its potential with effective biofouling control over long-term operation of the QQ MBR.

레이저 스페클 전단간섭법을 이용한 압력용기 내부결함의 측정 가능한 결함 크기의 평가 (Evaluation of Detectable Defect Size for Inner Defect of Pressure Vessel Using Laser Speckle Shearing Interferometry)

  • 김경석;선상우;최태호;강찬근;나만균;정현철
    • 비파괴검사학회지
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    • 제34권2호
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    • pp.135-140
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    • 2014
  • 최근 압력용기가 다양한 산업분야에서 사용되고 있다. 압력용기의 내부 또는 외부에 결함이 발생하면 대형 사고를 유발하게 된다. 압력용기의 외부에 발생하는 결함은 육안검사를 통해 어느 정도 해결이 가능하지만, 압력용기 내부에 발생하는 결함은 육안검사로는 측정하기 어렵다. 이러한 형태의 결함을 측정하기 위해서는 비파괴검사가 적합하다. 전단간섭법은 광계측을 이용한 비파괴검사법 중 하나이며, 비접촉식으로 전체 측정영역에 대해 실시간으로 한 번의 실험을 통해 결함을 측정할 수 있다는 장점을 지니고 있다. 본 논문에서는 레이저 스페클 전단간섭법을 이용하여 측정할 수 있는 압력용기의 내부에 존재하는 결함 크기를 평가하였다. ASTM A53 Gr.B 재질로 제작된 압력용기 시험편 내부에 인위적인 결함을 가공하고 공압을 이용하여 압력용기에 내압을 가하여 결함을 측정하였다. 실험을 통해 0.2 MPa의 압력차에서도 압력용기의 원래 두께의 25 %의 깊이로 발생한 결함까지는 측정 가능함을 확인하였다.

자긴가공된 압력용기의 잔류응력 평가 및 피로수명 예측 (Residual Stress Estimation and Fatigue Life Prediction of an Autofrettaged Pressure Vessel)

  • 송경진;김은겸;고승기
    • 대한기계학회논문집A
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    • 제41권9호
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    • pp.845-851
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    • 2017
  • 외경에 홈이 존재하는 자긴가공된 압력용기의 피로 파손은 외경 홈에서의 피로균열 발생과 전파에 의해 발생한다. 자긴가공된 압력용기의 피로수명을 예측하기 위하여 유한요소법을 이용하여 자긴가공에 의한 잔류응력해석을 수행하였으며, 피로시험을 통하여 재료의 피로특성을 구하였다. 압력용기의 수명은 압력용기 외경 홈 모서리에서 응력 및 변형률 집중에 의한 피로균열의 생성수명과 전파수명의 합으로 총 수명이 계산되었다. 본 연구에서 80 % 자긴도의 압력용기가 424 MPa의 반복적인 내압을 받을 때 압력용기의 수명은 2,598 사이클로 예측되었다.

파랑 및 부유체 운동을 고려한 세장해양구조물의 동적 거동 해석 (Dynamic Response Analysis of Slender Marine Structures under Vessel Motion and Regular Waves)

  • Chung Son Ryu;Michael Isaacson
    • 한국해안해양공학회지
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    • 제10권2호
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    • pp.64-72
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    • 1998
  • 해저자원개발에 사용되는 riser나 TLP의 인장각과 같은 세장해양구조물의 파랑 및 상단부유체의 운동에 대한 동적거동해석을 수행하였다. 구조부재의 유한요소모델을 사용한 수치해석기법을 개발하고 규칙파에 대한 시간영역해석을 수행하였다. 본 연구는 상단부유체의 수평 및 수직운동이 구조물의 횡방향거동에 미치는 영향을 분석하였으며, 특히 부유체 수직운동의 영향을 주로하여 패러미터연구를 수행하였다. 수심, 파랑조건 그리고 부유체운동 등 여러경우에 대한 구조물의 변의, 휨응력을 비교검토하였고, 이 해석을 통하여 부유체의 수직운동에 의한 시간변화 인장력으로 야기되는 불안정조건을 검토하였다. 예제해석결과, 부유체의 수평 및 수직운동의 상호작용으로 riser의 동적응답이 증폭되었다. TLP 인장각의 경우 부유체의 수직운동효과가 구조물의 거동에 상당히 크게 작용하는 것으로 나타났다.

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견인되는 선박의 조종성능 개선에 관한 연구 : 시스템 모델링 (A study on maneuvering performance improvement of a towed vessel without a power propulsion system: system modeling)

  • 트란덕권;이동훈;김태완;김영복;박환철
    • 수산해양기술연구
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    • 제54권4호
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    • pp.343-352
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    • 2018
  • In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessel looks like the barge ship, which is used for many purposes. In these vessels, basically, the power propulsion system is not installed but just towed by a towing vessel such as tugboats with ropes and wires. It means that the motions of towed vessel are basically dependent on the tracking route of towing boat. Therefore, in some cases, undesirable and unpredictable motions may be made by environmental factors such as wave, wind attack and so on. As a result, a collision accident with others may occur during maneuvering situation. Based on these facts, the authors try to encourage the steering performance of the towed vessel by using controllable rudders without any propulsion system. In this study, especially, a controllable vessel with three rudders is considered, and a mathematical model is induced for the future study. The model is described as surge, sway motion and inertia moment by following the general representation method for the surface ship.