• Title/Summary/Keyword: Heeled condition

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An Experimental Study on the Manoeuvrability of a Ship in Heeled Condition (횡경사상태 선박의 조종성능변화에 관한 실험적 연구)

  • Yun, Kunhang;Yeo, Dong Jin
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.3
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    • pp.273-280
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    • 2019
  • Predicting ship manoeuvrability is attracting widespread interest in the field of analyzing maritime accident to simulate a highly accurate track of a ship in abnormal accident situations. This study investigated the manoeuvrability of a ship in abnormally heeled condition. Free Running Model Tests (FRMT) with 1/65.83 scaled KCS (KRISO container ship) were conducted in three heeled conditions; $35^{\circ}$ turning circle tests and 20/20 zigzag manoeuvring tests were conducted in $0^{\circ}$, $-10^{\circ}$, and $-20^{\circ}$ conditions. The test results showed that the heeled to port condition significantly affected starboard turning and zigzag characteristics; the tactical diameters in the turning circle tests decreased, and the first overshoot angles in the zigzag tests increased when the ship was in the larger heeled condition. These results indicate that the roll angle of the ship considerably affects yaw rate and speed decrease of the ship. The turning and zigzag indices from trajectory and navigation data in the study were provided for benchmark data sets.

Prediction of Propulsive Performance of VLCC at Heeled and Trimmed Conditions (대형유조선의 경사상태011서의 저항추진 성능추정)

  • Yang, Ji-Man;Kim, Hyo-Chul
    • Journal of the Society of Naval Architects of Korea
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    • v.42 no.4 s.142
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    • pp.307-314
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    • 2005
  • In recent years, many environmentally disastrous oil spill accidents from damaged vessels become worse especially when the early treatment is not prompt enough. To properly handle this type of accidents and prevent further disasters, international organizations establish and impose various rules and regulations. In assessing the damages and providing salvage operations, the propulsive performance of damaged vessels is of great importance, as well as for containing oil spill while the vessels are being towed or self-propelled. Until now, many naval hydrodynamics researches have focused on the propulsive performance in normal operating conditions and only a few studies for damaged vessels are found in literature. In this paper experimental method is used to study the Propulsive performance of a very large crude-oil carrier (VLCC) in .heeled and/or trimmed conditions.

The Effect of Heel-height on the Lumbosacral Region Angle of Young Ladies (구두 굽 높이가 20대 여성의 요천추부 각도에 미치는 영향)

  • Kim, Byoung-Gon;Gong, Won-Tae;Kim, Han-Soo
    • Journal of the Korean Society of Physical Medicine
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    • v.2 no.1
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    • pp.49-59
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    • 2007
  • Objective : To purpose of this study was the most of the ladies wear high-heeled shoes at lease 4 to 5 day a week but the effect of it's height on the lumbo-sacral legion angle has not been clearly defined. Method : Subject were 20 young ladies, who had majored in physical therapy of the Dae-gu Health College. Method 1. PACS system X-ray was used to measure the lumbo-sacral legion angle under the condition of bare foot, 3cm, 7cm high-heeled at standing position. 2. Spinal Mouse was used to measure the spinal segment motion angle and length under the condition of bare foot, 3cm, 7cm high-heeled at being Flexion-Extension position Result : The result of this study were as follow I. Significant statistical increase in lumbar lordosis was observed as the heel height was increased from bare foot to 7cm high-heeled(p<.05), but there was no significant difference in the lumbo-sacral angle & sacral angle(p>.05). 2. The Height and the weight of the subjects, their preference on the shoes didn't affect the lumbo-sacral lesion angle(p>.05) 3. The variation of the heel height didn't affect the spinal segment motion angle and length(p>.05). Conclusion : There is strong relationship between the high of heel with increasing the lumbar lordosis(p<.05).

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A Study on the Effect of the Heeled and Trimmed Conditions on Propulsive Performance of VLCC (대형유조선의 저항추진성능에 미치는 자세변화의 영향에 관한 연구)

  • Yang, Ji-Man;Rhee, Shin-Hyung;Kim, Hyo-Chul
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.3 s.147
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    • pp.275-284
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    • 2006
  • In recent years, many environmentally disastrous maritime accidents resulted from oil or fuel spills from damaged vessels. The situation becomes worse especially when the early counter treatment is not prompt enough. To properly handle this type of accidents and prevent further disasters, the propulsive performance of damaged vessels must be better understood for salvage operations, as well as for containing oil spills while the vessels are being towed or self-propelled. Until now, many hydrodynamic studies have focused on the propulsive performance of undamaged vessels but only a few studies on that of damaged vessels. in this paper, both experimental and computational methods are used to study the propulsive performance of a VLCC in heeled and/or trimmed conditions. For experimental studies, measurement systems should be modified to adapt to the variations of attitude of a damaged vessel. For numerical studies, CFD programs should be also extended to be applied to asymmetrically floating conditions.

The Effect of The Drift Velocity on The Ship Motion (표류(漂流)를 고려한 선체운동(船體運動))

  • J.H.,Hwang;Y.J.,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.18 no.3
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    • pp.29-38
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    • 1981
  • In general the drift result in ship heeling, thus it seems to be necessary to analyze the ship motion by considering both the drifting and heeling phenomena. In this paper, a drift velocity and a heeling angle are given as prior conditions, and then within the linear potential theory the hydrodynamic coefficients and wave exciting forces and moments are derived for a ship advancing and drifting with constant speeds. And numerical calculations are preformed for a cylindrical body of shiplike cross section at zerp forward velocity. The 2-D hydrodynamic forces and moments of a heeled cylinder are calculated by using the Frank Close-Fit method. These numerical results for the oscillating cylinder without drift velocity have shown better agreements with experimental data than the numerical results of Kobayashi[2]. The motion responses for a drifting cylinder are calculated ignoring the drift velocity effect in the free surface condition. The accuracy of these calculations can not be verified, because the experimental data are not available. Through these numerical calculations to so concluded that drift velocity effects on the body motion are signiffcant.

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Forefoot disorders and conservative treatment

  • Park, Chul Hyun;Chang, Min Cheol
    • Journal of Yeungnam Medical Science
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    • v.36 no.2
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    • pp.92-98
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    • 2019
  • Forefoot disorders are often seen in clinical practice. Forefoot deformity and pain can deteriorate gait function and decrease quality of life. This review presents common forefoot disorders and conservative treatment using an insole or orthosis. Metatarsalgia is a painful foot condition affecting the metatarsal (MT) region of the foot. A MT pad, MT bar, or forefoot cushion can be used to alleviate MT pain. Hallux valgus is a deformity characterized by medial deviation of the first MT and lateral deviation of the hallux. A toe spreader, valgus splint, and bunion shield are commonly applied to patients with hallux valgus. Hallux limitus and hallux rigidus refer to painful limitations of dorsiflexion of the first metatarsophalangeal joint. A kinetic wedge foot orthosis or rocker sole can help relieve symptoms from hallux limitus or rigidus. Hammer, claw, and mallet toes are sagittal plane deformities of the lesser toes. Toe sleeve or padding can be applied over high-pressure areas in the proximal or distal interphalangeal joints or under the MT heads. An MT off-loading insole can also be used to alleviate symptoms following lesser toe deformities. Morton's neuroma is a benign neuroma of an intermetatarsal plantar nerve that leads to a painful condition affecting the MT area. The MT bar, the plantar pad, or a more cushioned insole would be useful. In addition, patients with any of the above various forefoot disorders should avoid tight-fitting or high-heeled shoes. Applying an insole or orthosis and wearing proper shoes can be beneficial for managing forefoot disorders.

An Experimental Study on the Change in Manoeuvring Performance According to the Static Heel Angle of a Twin-Screw Ship (쌍축선의 정적 횡경사각에 따른 조종성능 변화에 관한 실험적 연구)

  • Kwon, Chang Seop;Yun, Kunhang;Yeo, Dong Jin
    • Journal of the Society of Naval Architects of Korea
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    • v.58 no.6
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    • pp.407-414
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    • 2021
  • The manoeuvrability of a ship with an unwanted heel angle due to a maritime accident is changed from the original characteristics. The purpose of this study is to quantitatively investigate the change in the manoeuvring performance of a twin-screw ship under various hee angles and speed conditions. A series of free running model test campaigns were performed in the Ocean Engineering Basin of Korea Research Institute of Ships & Ocean Engineering (KRISO) for a twin-screw car ferry vessel. Turning circle test and zig-zag 10/10 and 20/20 tests were carried out on the heel angles of 0, -10, and -19.5 degrees. In addition, two-speed conditions were considered to understand the effect of ship speed. In order to examine the effect of the bilge keel, a heel angle of -22 degree where the bilge keel is exposed outside the water surface, was considered. Finally, the change of manoeuvring characteristics according to the heel angle for a twin-screw and a single-screw vessel is discussed.

Effect of Shoe Heel Height on Vastus Medialis and Vastus Lateralis Electromyographic Activity During Stair Ascending and Descending (신발 뒤굽 높이가 계단 올라가기 및 내려오기 동안 내측광근과 외측광근의 근 활성도에 미치는 영향)

  • Oh, Duck-Won;Kim, Suhn-Yeop
    • Physical Therapy Korea
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    • v.16 no.3
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    • pp.24-31
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    • 2009
  • This study aimed to investigate the effect of differing heel heights on the electromyographic (EMG) activity in vastus medialis (VM) and vastus lateralis (VL) during stair ascending and descending activities. A total of 26 healthy women volunteered to perform stair-ascending and stair-descending tasks with 3 heel heights: barefoot, 3 cm, and 7 cm. The EMG activities of the VM and VL were recorded during the tasks. During the stair ascending and descending tasks, the EMG activities of both VM and VL significantly changed with differing the heel heights (p<.05). Moreover, the EMG activities of VM and VL during the stair ascending task were significantly higher than the corresponding values during the stair-descending task (p<.05). However, there were no significant differences between the VM:VL EMG ratios for the 3 heel heights (p>.05). The VM:VL EMG ratios between the 2 tasks differed significantly in the 7 cm high heel condition (p<.05). Despite an increase in the EMG activities in both VM and VL during stair ascending and descending tasks, there was no change in the relative EMG intensities of VM and VL, which was measured by calculating the VM:VL ratio this result indicates that no VM:VL imbalances were elicited. The relative EMG intensities of VM and VL during stair descent were lower than the corresponding values during the ascent, suggesting that VM and VL may show an imbalance in the eccentric activation during the weight-acceptance phase. This study provides useful information that will facilitate future research on how heel height affects muscle activity around the knee joint.

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