• Title/Summary/Keyword: (1,1)-knots

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Mechanical Properties and Comparisons of Cerclage Wires of Various Diameters in Different Knot Methods

  • Jang, Aram;Kim, Jieyoo;Park, Ji-Hun;Yoon, Eunchae;Lee, Dongbin;Lee, Jae-Hoon
    • Journal of Veterinary Clinics
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    • v.39 no.4
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    • pp.149-155
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    • 2022
  • The aim of this study was to compare the mechanical properties of 0.6 and 0.8 mm cerclage wires with the 1.0 mm cerclage wire in the twist, single-loop, double-loop, double-wrap, and loop/twist knot methods. Six stainless steel cerclage wires of various diameters in different knot methods were tied round a customized jig mounted on a load testing machine. The initial tension, initial stiffness, and yield load were evaluated. The failure mode of each cerclage was observed. For each wire size, the double-loop, double-wrap, and loop/twist knots showed significantly greater initial stiffness, and yield load than those seen with twist and single-loop knots. The single-loop knot showed the least initial stiffness regardless of the diameter. As the cerclage wire diameter increased, the cerclage tended to show significantly greater initial stiffness, and yield load. Failure modes varied depending on the knot configurations. Single-loop knots of smaller-diameter wires less than 1 mm had similar or lower initial tension, initial stiffness, and yield load than a twist knot. Owing to the variance in mechanical properties, the clinical application of the knot type should depend on the diameter of the cerclage wire.

The Opening Size Change for Screen Tension (스크린 망사의 견장과 오프닝의 변화)

  • Jung, Gi-Young;Kang, Young-Reep
    • Journal of the Korean Graphic Arts Communication Society
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    • v.28 no.1
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    • pp.43-50
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    • 2010
  • The 200mesh screen was tensioned and fixed on a frame. When applied tension to 5N and 10N per unit area, a side length of opening of the screen was 163.223${\mu}m$ and 168.224${\mu}m$, respective. But side length not tensioned was 158.879${\mu}m$. We knew that a side length of opening of the screen rarely changes with tension applied to the screen. The appearances that a side length of opening of the screen expand little are due to a decreasing diameter of thread by means of tension. In a thickness measurement of screen, While the high density mesh screen that had a lot of knots that crossed a line of latitude and longitude per unit area appeared a higher numerical value, the low density mesh screen that had a few knots appeared a low numerical value.

A Study on the Time Required and Error Tolerance Limits for Flight Data Computation (비행자료산출을 위한 소요시간과 정답오차범위에 관한 연구)

  • Kim, Chil-Young;Han, Kyoung-Keun
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.6 no.1
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    • pp.21-29
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    • 1998
  • The purpose of the present paper is to determine the time required and error tolerance limits for flight data computation. The results of statistical analysis showed that the calculator side computation required about 50 seconds for each question and wind side computation needed about 115 seconds for each question. In case of error tolerance limits, it was found that the error tolerance limit for altitude computation war 90 feet and two knots of interval was recommanded for the speed computation in calculator side, and one degree of interval for heading computation and five knots interval for speed computation in wind side.

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A Study on Decision of Minimum Required Channel Width Considering Ship Types by Fast Time Simulation (배속 시뮬레이션 기반의 선종별 최소 항로 폭에 관한 연구)

  • Kim, Hyun-suk;Lee, Yun-sok
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.4
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    • pp.309-316
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    • 2020
  • Waterway design should prioritize appropriate channel width to ensure preferential safe passage for the arrival and departure of vessels. To calculate the minimum channel width required for safe passage a comprehensive review of several factors is required. These factors include vessel maneuverability, determined by vessel size, type and speed; environmental factors such as wind, tide, and wave action; human factors, including personal experience and operator judgment as well as marine traffic and navigation support facilities for decision making. However, the Korean channel width design standard is based only on vessel length, and requires improvement when compared with the standards of PIANC, USA, and Japan. This study aims to estimate the appropriate channel width required for one-way traffic in a straight channel, considering various vessel and environmental factors, using Fast Time Simulation (FTS). When the wind speed is 25 knots, with a current speed of 2 knots and a normal vessel speed of 10 knots FTS shows that a 150K GT Cruise Ship requires a minimum channel width of 0.67-0.91 the vessel length (L), whereas a 120K TEU Container Ship and a 300K DWT VLCC require 0.79-1.17 and 1.02-1.59, respectively. Such results can be used to calculate the minimum channel width required for safe passage as an improved Korean design standard.

Numerical Analysis on the Flow Field around Tiller Rotor for Soil Improvement in Coastal Fisheries (연안어장의 토질 개선을 위한 경운기 로터 주변의 유동장에 대한 수치해석)

  • Kim, Jang-Kweon;Oh, Seok-Hyung
    • Journal of Power System Engineering
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    • v.21 no.5
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    • pp.20-28
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    • 2017
  • The steady-state, incompressible and three-dimensional numerical analysis was performed to investigate the flow fields around the seabed tiller used for soil improvement in coastal fisheries and the pulling force and buoyancy generated by tiller operation. The turbulence model used in this study is a realizable $k-{\varepsilon}$. As a results, at a stationary current or a current speed of 1.2 knots, where rotor rotates in a clockwise direction, a typical vortex pair appears near the tip of the rotor except for the edge, and the strength of the vortex pair increases with the number of revolutions of the rotor. The pulling force of the tiller rotating in the counterclockwise direction increases with the number of revolutions. Also, when the current flows at 1.2 knots and the rotor rotates clockwise, the pulling force of the tiller acts on the upstream side irrespective of the number of rotations of the rotor, so that no force is applied. The buoyancy of the tiller acts on the seawater surface if the flow direction inside the rotor is the same as the direction of rotation of the rotor, regardless of the current velocity, otherwise it acts on the seabed.

Types and Characteristics of Chinese Hyangnang (중국 향낭의 유형과 특성)

  • Lee, Joo-Young;Lee, Kyung-Hee;Kwon, Young-Suk
    • Journal of the Korean Society of Costume
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    • v.56 no.8 s.108
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    • pp.1-14
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    • 2006
  • This study is to examine the Hyangnag used in China. Results of the study can be described as below. 1. Hyangnang was also called Hyangdae, Hyanghapo, Hunnang and Chunnang. Perfumes were used to make the body and clothes diffuse a good fragrance. And Perfumes were used to prevent insects and remove related pollutions. It was possible to prevent insects when perfumes were burnt out. 2. In the Han, Song, Yao and Win periods, Hyangnang had Cylinderical, Rectangular, Cylinderical and Rectangular, Circular and Calabach types. These various types were developed into one, Norigae type, in the period of Ching. 3. Hyangnang were decorated mainly with embroideries, knots and seams. Embroideries were applied always onto the surface of Hyangnang. Knots were used mainly in the Song and Win periods, decorative seams were used mainly in the Ching. 4. From the Han to Yao periods, Hyangnang was made of perforate textiles like na and Sa for practical reasons, making perfume smells more easily diffused. From the Win to Ching periods, Hyangang was made of dense textiles like silk and Dan, which could be easily embroidered for decoration purposes. 5. Hyangnang was often hanged down from the waistband and up onto the fore chest or the elbow, or put into the liner of the sleeve. 6. Hyangnang has immanent implications of symbolism, ideology and aristocraticism.

Numerical Analysis on Velocity Fields around Seabed Tiller for the Improvement of Seabed Soil (해저 토질 개선을 위한 해저경운기 주변의 속도장에 대한 수치해석)

  • Kim, Jang-Kweon;Oh, Seok-Hyung;Kim, Jong-Beom;Chung, Sang-Ok
    • Journal of Power System Engineering
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    • v.21 no.2
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    • pp.48-56
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    • 2017
  • The steady-state, incompressible and three-dimensional numerical analysis was carried out to evaluate the velocity fields around the seabed tiller used for the improvement of the seabed soil and the pulling force and buoyancy generated by driving the seabed tiller. The turbulence model used in this study is a realizable $k-{\varepsilon}$ well known to be excellent for predicting the performance of the flow separation and recirculation flow as well as the boundary layer with rotation and strong back pressure gradient. As a results, a typical vortex pair appears near the adjacent rotor vane tip. When the current is stopped, there is no force when pulling the seabed tiller, but when the current flows at 1.2 knots, the force acts on the downstream side and the pulling force is much greater. In stationary currents, the buoyancy of the seabed tiller acts more strongly towards the seabed as the number of rotations of the rotor increases, but acts more strongly toward the sea surface at 1.2 knots of current.

A study on the measurement of ice in the Arctic region (At Svalbard and Chukchi Sea on 2010 summer) (빙해역의 빙상환경 계측에 관한 연구 (2010년 여름 Svalbard와 Chukchi Sea 근해))

  • Kim, Hyun Soo
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.1
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    • pp.23-29
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    • 2011
  • The measurement of ice properties such as thickness, strength are important to know the performance of the ice breaking vessel. The measuring equipment of ice properties and methods are summarized in this paper. The actual measured data are also described. The strength of ice at Svalbard area on April 2010 is much stronger than the Chukchi Sea on August 2010. The mean strength of Svalbard is about 500 kPa and one of Chukchi Sea is 250 kPa. The first sea trial in Arctic sea using Araon was carried out in the Chukchi Sea. The power and speed was also measured to check the ship performance in ice. The speed was measured from GPS(Global Positioning System) and engine power was recorded from DPS(Dynamic Positioning system) of Araon. The design target of Araon in level ice is 3 knots in 1m thickness and 630 kPa flexible strength but mean speed in Chuckchi sea is 3.98 knots when 6.6 MW engine power, 2.4m ice thickness and 250 kPa strength. This results comes from the difference of ice types and the weak flexible strength of ice but it will be a good information to know the performance of Araon in similar ice condition.

A Simple Theoretical Model for the Upwind Flow in the Southern Yellow Sea (황해남부의 역풍류에 대한 단순 이론 모델)

  • 박용향
    • 한국해양학회지
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    • v.21 no.4
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    • pp.203-210
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    • 1986
  • A linear parallel transport model is formulated and applied to an idealized Yellow Sea, With this simple analytical model, the hither-to suspected upwind flow phenomena in the southern Yellow Sea can be reasonably explained. In deep waters where the local depth exceeds a critical depth (Hc=53m in the present model sea), pressure gradient force dominates over wind stress and contributes to an upwind flow. The estimated upwind flow velocity increases with wind speed and a maximum upwind flow occurs along the axis of the Yellow Sea embayment. For the typical south wind of 5-10 knots in summer, the upwind (southward) flow velocity along the axis of the Yellow Sea is estimated to be 1-5cm s$\^$-1/. While, for the typical north wind of 10-15 knots in winter, the upwind (northward) flow velocity is 5-12cm s$\^$-1/. These velocity ranges can be served as rough estimates for the intrusion velocity of the Yellow Sea Bottom Cold Water in summer and the Yellow Sea Warm Current in winter, respectively.

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