• Title/Summary/Keyword: Knots

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A Study on the Bending Performance of Structural Size Lumbers Using the ANSYS (ANSYS를 이용한 실대재의 휨특성에 대한 연구)

  • Kim, Gwang-Chul
    • Journal of the Korea Furniture Society
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    • v.22 no.4
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    • pp.323-329
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    • 2011
  • In our country, domestic species can not be used as a structural member because we have not yet grading system. So, to utilize as a basic data of grading system, bending test and numerical modelling on structural member were conducted in this study. 35 of Douglas-fir, 2" ${\times}$ 6", span 2.4 m were tested for the bending properties, and Ansys software was used to analyze the numerical modelling on the structural members. The data of knots were inspected and applied in numerical modelling. To obtain the accuracy of analysis, nonlinear numerical analysis was carried out instead of linear numerical analysis. Ultimate load had a wide range from 4883N to 11,738 N, and maximum deformation also had a range from 26 mm to 68 mm. Average of ultimate load was 8,616 N, and that of maximum deformation was 48 mm. The distinctive features of failure types were simple tension type and cross-grain tension type. Ulitmate load and maximum deformation from numerical modelling were 7,504 N and 37 mm. The numerical modelling drawn by this study is available to all species, and reasonable prediction on the bending performance is possible with only some material properties.

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A Study on Organistic Line Extension on Digital Space - Focus on NOX digital space - (디지털 공간에 나타난 선의 유기체적 확장성에 관한 연구 - NOX 디지털 공간을 중심으로 -)

  • Yu, Mi-Yeon;Yoon, Jae-Eun
    • Korean Institute of Interior Design Journal
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    • v.17 no.3
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    • pp.148-155
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    • 2008
  • The following research focuses on the formation method of digital space by organistic line extension among various digital formation methods. The paper reflects on the meaning and concept of today's digitalism which enables the application of complex organistic system on space through advanced technology. It also explores the concept of a line in topology which differs in assumptive meaning from traditional Euclidian geometry. The findings of the research are that first, digital space is not optimized, but is a tentative formation in process. A digital space encompasses characteristics such as infinity, possibility, potential, asymmetry, and the force of virtuality such characteristics are expressed through a moving surface constantly changing with direction. Second, a digital space formed by line extension is inseparable and durable since no measurement or dimension is predetermined. Furthermore, its sense of direction and flexibility gives it a feeling of a living organism. Third, a Euclidian methodology called 'NURBS' is being developed to express such a dynamic digital space; this is reflected through three elements, control point, weights, and knots to effectively reflect the characteristics of virtuality. The opportunities of digital space are infinite, and the possibilities of formation methods likewise vast.

Study of Hull Form Development and Resistance Performance of Catamaran-type High Speed Fishing Leisure Boat (고속 쌍동형 낚시 레저보트 선형개발과 저항성능에 관한 연구)

  • Jeong, Uh-Cheul;Kwon, Soo-Yeon;Choi, Ji-Hoon;Kim, Do-Jung;Hong, Ki-Sup
    • Journal of Ocean Engineering and Technology
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    • v.27 no.6
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    • pp.1-6
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    • 2013
  • A 25ft class fishing leisure boat is developed, and the resistance performances are investigated by a model test in a high-speed circulating water channel. The design speed of the developed ship is 25 knots using a 150 ps outboard engine. A catamanan type hull form using a planing section is adopted considering the Froude number and large deck area. The effect of a center body attached on the bottom of the cross deck is studied under various conditions. Wave patterns are observed to make clear the relationship between the resistance performance and the wave characteristics. The results show that the shape of the center body and the position of the chine line can have a strong effect on the resistance performance in a certain velocity range.

Design and Construction of Long-Range High-Speed Foil Catamaran Passenger Ship (장거리 고속 수중익 쌍동 여객선의 설계와 건조)

  • Keh-Sik Min;Oi-Hyun Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.3
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    • pp.1-15
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    • 1993
  • In response to the growing domestic request and the change of the overseas environment, Hyundai Maritime Research Institute has recently established a three-stage development plan for the high speed marine transportation system. As the first stage plan, the long-range high-speed foil catamaran passenger ship has been designed and constructed for the open-sea serivice of 800 nautical miles round trip with top speed above 40 knots. Extensive theoretical analyses and model tests were systematically carried omit along the course of design for the system optimization and the verification. In this paper, the brief summary of the design and the construction works shall be presented.

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Haewon-sangsaeng as a Religio-Ethical Metaphor

  • HUANG, Pochi
    • Journal of Daesoon Thought and the Religions of East Asia
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    • v.1 no.1
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    • pp.103-125
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    • 2021
  • This paper deals with figurative meanings of Haewon-sangsaeng. It is an investigation which is both semantic and diachronic. In the first part, important implications of sangsaeng (or xiangsheng in Chinese) in the context of correlative cosmology are extensively explored. Among others, saeng (in Chinese sheng) as a powerful metaphor and its related Chinese compounds are broadly discussed. In the second part, the evolution of ideas of yuan (or won in Korean) in Chinese history is explicated. Above all, in the traditional Chinese cultural milieu, wrongful treatments which make victims feel themselves aggrieved are socio-politically orientated. The Scripture on Great Peace (Taiping Jing) is used as reference point to elucidate the essential points of yuan and its knots. However, the advent of Buddhism in East Asia adds a new dimension to the understanding of yuan (won). Accumulated yuan as karmic bond thus gives a new identity of yuan as predetermined animosity. Widely recognized idioms like "adverse relatives and karmic debtors" and indigenous Chinese Buddhist rituals like Repentance Ritual of the Emperor Liang bear witness to this transformation of the meaning of yuan in East Asia. The fruitful yet correlated meanings of yuan also make the endeavor of untying yuan deeply significant and important to human society. Haewon-sangsaeng, as a religio-ethical ideal, brings out an amicable and harmonious relationship among myriad beings in the cosmos.

Arthroscopic Capsular Repair without Relaying Sutures: 'Simple Sewing Technique'

  • Kim, Hyungsuk;Song, Hyun Seok;Kang, Seung Gu;Han, Sung Bin
    • Clinics in Shoulder and Elbow
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    • v.22 no.3
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    • pp.146-148
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    • 2019
  • We report a simple technique for repairing capsular tear, using only a hook-like, cannulated instrument and braided sutures without relaying steps. A No. 2 braided suture is passed through the lumen of the instrument. Under direct arthroscopic view, the tip of the instrument is passed through the side of the capsule that has previously been separated with the probe. One end of the suture is retrieved with a grasper through a separate portal. The tip is moved back without withdrawing through the skin, and reinserted into the other side of the capsule. Holding the end retrieved earlier, the other end of the suture is retrieved with a suture retriever. After complete removal of the instrument, the suture is tied through a cannula using the standard knot tying techniques. The same procedures are repeated for other required knots.

Correction Methods and Validation for Environmental Conditions in the Ice Field Trials (빙해역 시운전 해석을 위한 환경조건 보정 방법 및 검증)

  • Kim, Hyun Soo
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.2
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    • pp.117-127
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    • 2019
  • Vessel's ice speed performances will be verified in ice sea trial but environmental conditions of ice fields are changeable according to the weather condition of ice trial area. Speed performance has to correct in the no wind, wave and current etc. after sea trial. Especially finding ice fields which is exact the same as owner's ice thickness and strength requirements is not easy. Therefore speed correction according to environment condition has to be done after sea trial measurements. Correction methods for ice thickness, ice strength, wave, wind and ship draft, trim, ice drift etc. are checked in ice sea trial based on literature review such as ISO standard, ITTC recommendation, journal papers and proceedings of conferences. Possibility of application for current and ice drift correction in ice field are discussed and measuring schemes and procedures of correction methods are described in this paper. All of correction schemes are calculated for 'Araon' which is ice breaking research vessel with Arctic and Antarctic ice field test results. Analyzed results shows that Araon is satisfied with her official ice speed performance of 3 knots with 10MW power at 1m ice thickness, 570kPa ice flexural strength.

Performance Evaluation of 20 HP Outboard Motor in Consideration of Driving System Applied to Electric-Propulsion Boat (전기추진 선박에 적용되는 20HP급 전기추진 선외기 구동시스템의 성능평가에 대한 고찰)

  • Moon, Byung Young;Shin, Kuk Hwan;Lee, Ki Yeol
    • Journal of Ocean Engineering and Technology
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    • v.32 no.6
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    • pp.518-526
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    • 2018
  • As a new technical approach, this paper introduces a method for improving an electrically propelled outboard motor in consideration of the driving system applied to an electric-propulsion boat with solar cell energy. The most efficient model for a drive shaft, propeller shaft, and bevel gear was suggested and examined with respect to the results of test operation in prototype mode. Furthermore, this research included a performance evaluation of the manufactured prototype to acquire the purposed quantity value and the development items. After manufacturing the desired prototype of an electrically propelled outboard motor, the maximum sail time, thrust force, noise, and weight were evaluated in a performance test. An additional test in relation to the maximum sail speed (knots) of the completed prototype was conducted using a sea trial evaluation to acquire the optimum quantity.

Investigation of Optimum Cathodic Protection Potential to Prevent Erosion with a Flow Rate of AA5083-H321 for Marine Vessels (선박용 AA5083-H321의 유속에 의한 침식손상 방지를 위한 최적 음극방식전위 규명)

  • Chong, Sang-Ok;Park, Il-Cho;Kim, Seong-Jong
    • Corrosion Science and Technology
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    • v.19 no.6
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    • pp.288-295
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    • 2020
  • This study investigated the erosion-corrosion characteristics of 5038-H321 aluminum alloy in a natural seawater solution through various electrochemical experiments and flow rate parameters. Cathodic polarization experiments were conducted at flow rates ranging from 4 to 12 knots. Considering the concentration polarization section representing a relatively low current density, the range of the potentiostatic experiment was determined to be -1.6 to -1.0 V. The potentiostatic experiment was conducted at various potentials for 180 minutes in seawater. After the experiment, the corrosion characteristics were evaluated by observing surface morphology and measuring surface roughness. As a result, as the applied potential was lower, the amount of calcareous deposits increased and the roughness tended to increase. On the other hand, it was confirmed that the roughness was larger in the static condition than the flow rate condition due to the influence of the flow velocity. Variations in the chemical composition with flow rate variations were analyzed by energy-dispersive spectroscopy (EDS). In conclusion, the cathodic potential of AA5083-H321 in seawater was determined to be -1.0 V.

Comparative study on the prediction of speed-power-rpm of the KVLCC2 in regular head waves using model tests

  • Yu, Jin-Won;Lee, Cheol-Min;Seo, Jin-Hyeok;Chun, Ho Hwan;Choi, Jung-Eun;Lee, Inwon
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.13 no.1
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    • pp.24-34
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    • 2021
  • This paper predicts the speed-power-rpm relationship in regular head waves using various indirect methods: load variation, direct powering, resistance and thrust identity, torque and revolution, thrust and revolution, and Taylor expansion methods. The subject ship is KVLCC2. The wave conditions are the regular head waves of λ/LPP = 0.6 and 1.0 with three wave steepness ratios at three ship speeds of 13.5, 14.5 and 15.5 knots (design speed). In the case of λ/LPP = 0.6 at design speed, two more wave steepness ratios have been taken into consideration. The indirect methods have been evaluated through comparing the speed-power-rpm relationships with those obtained from the resistance and self-propulsion tests in calm water and in waves. The load variation method has been applied to predict propulsive performances in waves, and to derive overload factors (ITTC, 2018). The overload factors have been applied to obtain propulsive efficiency and propeller revolution. The thrust and revolution method (ITTC, 2014) has been modified.