• Title/Summary/Keyword: Turning effect

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The Analysis of the Ship's Maneuverability According to the Ship's Trim and Draft (선박 TRIM변화에 따른 조종성능의 분석)

  • PARK, Byung-Soo;KANG, Donghoon;KANG, Il-Kwon;KIM, Hyun-Mu
    • Journal of Fisheries and Marine Sciences Education
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    • v.27 no.6
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    • pp.1865-1871
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    • 2015
  • Ship's trim is the one of the most important factor for safety at the sea. Turning circle test and Z-test were carried out to find the effect of ship's trim and draft changes. The results are as follows. 1. If the ship's draft and trim became large, turning circle would be wide. 2. If the ship's draft and trim became large, ship's drift angle would be small. Small drift angle made wide turning circle. 3. Trim by the head made slow ship's final speed when turning circle test. 4. By Z-test, the deeper draft and trim by the stern made small OSA. Small OSA means strong ship's stability. 5. Totally 2nd OSA is smaller than 1st OSA on Z-test. 6. There were small differences of 2nd OSA in trim by the stern, but there were large OSA in trim by the head. 7. The larger trim by the stern, the smaller OSW. The small OSW means better ship's stability and maneuverability.

An Experimental Study on the Turning Property of Welded Material (용접부의 선삭특성에 관한 실험적 연구)

  • Jang, Bok-Deuk
    • Journal of the Korean Society for Precision Engineering
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    • v.3 no.3
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    • pp.13-21
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    • 1986
  • Turning property of metal is affected by the cutting condition, tool geome- try and cutting material. But the turning property of welded material is not welknown. Welded structures usually contain nonhomogeneity, defects and resi- dual stresses due to differential contraction between welded metal and base metal. In this paper, authors conducted the experimental test on the turning property, by changing turning condition and welding electrodes of the welded specimens. The results obtained in these experimental tests are as follows; (1) Within the limit of this experimental test, the cutting force of the weld zone is bigger than that of base metal, and this phenomena is caused by the different mechanical property of the weld zone. The range of the variation of cutting force in the weld zone is caused by the nonhomogeneity of the weld zone, respectively. (2) The surface roughness follows the general characteristic of the effect of cutting condition on the surface roughness and the surface roughness of the weld zone shows coarse surface comparing with that of the base metal. (3) The specimen welded by the electrode E4301, shows worse cutting property than that of E4361 and E4313.

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The Effect of Turning Training on Figure of 8 Tract on Stoke Patients' Balance and Walking (8자 모양 트랙을 이용한 방향전환 훈련이 뇌졸중 환자의 균형 및 보행에 미치는 영향)

  • Kim, Mi-Gan;Kim, Joong-Hwi;Park, Ji-Won
    • The Journal of Korean Physical Therapy
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    • v.24 no.2
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    • pp.143-150
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    • 2012
  • Purpose: This study was intended to discover the effect of the turning training on figure of 8 tract on stroke patients' static and dynamic balance, as well as walking. Methods: A total of 42 stroke patients participated in this study. The training group was trained on the figure of 8 tract, while the control group was trained on the straight path for 30 minutes per day, for 4 weeks. Berg balance scale was used to measure the balance of the patients, before and after the training, and Good balance system was used to measure the sway speed and the distance of COG while standing. To measure the ability of walking, TUG and FSST were also used. Results: There were significant increases in the average score of Berg balance scale, in both groups after the training, and also significant difference between both groups were observed. The training group showed significant differences in the static balance ability, as well as anteroposterior and mediolateral sway speed. Further, there were significant increases in the dynamic balance ability, COP total distance, and TUG in both groups. The results showed more differences in comparing the control group with that of the training group. In FSST, there was no change in the control group, but there was a significant increase in the training group. Conclusion: Turning training on figure of 8 tract in stroke patients significantly increased the static and dynamic balance and walking ability. Based on the results, it can be seen that the training on the figure of 8 tract can influence the ability of balance and walking, which can lead to appropriate reactions to the change of environment and various tasks. Thus, it is assumed that turning training on figure of 8 tract as a means of improving the condition of stroke patients can be a meaningful program.

Effect of Direction to be Used for the Timed Up and Go Test on Walking Time in Stroke Patients (일어서서 걷기 검사 시 회전 방향이 뇌졸중 환자의 보행 시간에 미치는 영향)

  • Lee, Geon;Cho, Cheol-hoon;Lim, Kyung-jin;Lee, Joo-hyun;Yoon, Gyu-ri;Woo, Young-keun
    • Physical Therapy Korea
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    • v.23 no.2
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    • pp.11-19
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    • 2016
  • Background: In the stroke patients with the characteristics of hemiplegic gait, turning direction of the affected and unaffected side influences turning time. Therefore, it is important to investigate the walking response to turning directions in stroke patients. Objects: This study aimed to measure the walking time while turning direction in hemiplegic patients depending on balance ability measured by Berg Balance Scale. Methods: A group of forty-five subjects with stroke (Berg Balance Scale score${\geq}46$ were twenty-eight, Berg Balance Scale score${\leq}45$ were seventeen) were enrolled in this study. Subjects were asked to perform the Timed Up and Go test. Testing indications included two directions for turning in each subject. These indications were for turning toward the affected and unaffected side in stroke patients. The duration of total analysis duration, sit to stand phase, stand to sit phase, mid-turning phase, and end turning phase were recorded. The obtained data were analyzed by using paired t-test and Wilcoxon signed rank test in the group that are below and above 45 points of Berg Balance Scale score. The significance level was set at ${\alpha}=.05$. Results: There were significant increase time in the analysis duration and end turning phase duration while subjects were turned the unaffected side in stroke patients that presented a Berg Balance Scale score${\leq}45$ (p<.05). However, the comparison between the affected side and the unaffected side in the stroke patients with Berg Balance Scale score${\geq}46$, revealed no significant differences of the measured parameters. Conclusion: This finding should be suggested in the specific definition of turning direction for evaluation with Timed Up and Go test in the Berg Balance Scale score${\leq}45$, and other intervention for hemiplegic patients need to be suggested the direction of turning during walking training program.

A Study on the Maneuverability of a Rolling Ship under Wind Forces (풍력(風力) 및 횡요(橫搖)의 영향(影響)을 고려(考慮)한 선박(船舶)의 조종성능(操縱性能)에 관한 연구(硏究))

  • Jin-Ahn,Kim;Seung-Keon,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.21 no.1
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    • pp.3-12
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    • 1984
  • Up to now, it has been common to treat the maneuvering motion of a ship as a 3-degree-freedom motion i.e. surge, sway and yaw on the sea surface, for the simplicity and mathematical calculation, and it is quite acceptable in the practical point of view. Meanwhile, considering the maneuverability of a ship under the special conditions such as in irregular waves, in wind or at high speed with small GM value, it is required that roll effect must be considered in the equation of ship motion. In this paper the author tried to build up the 4-degree-freedom motion equation by adding roll. And then, applying the M.M.G.'s mathematical model and with captive model test results the roll-coupled hydrodynamic derivatives were found. With these the author could make some simulating program for turning and zig-zag steering. Through the computer simulations, the effect of roll to the ship maneuver became clear. The effect of the wind force to the maneuverability was also found. Followings are such items that was found. 1) When roll is coupled in the maneuvering motion, the directional stability becomes worse and the turning diameter becomes smaller as roll becomes smaller as roll becomes larger. 2) When maneuver a ship in the wind, the roll becomes severe and the directional stability becomes worse. 3) When a ship turns to the starboard side, the wind blowing from 90 degree direction to starboard causes the largest roll and the largest turning diameter, and the wind from other direction doesn't change the turning diameter. 4) When a ship is travelling with a constant speed with rudder amidship, if steady wind blows from one direction, the ship turns toward that wind. This phenomenon is observed in the actual seaways.

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Changes in Quality Parameters of Tomatoes Harvested at Different Mature Stages during Storage (수확시의 숙도에 따른 저온저장 중 토마토의 품질인자의 변화)

  • Choi, Jeong Hee;Jeong, Moon Cheol;Kim, Dongman
    • Food Science and Preservation
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    • v.20 no.2
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    • pp.151-157
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    • 2013
  • This study was conducted to investigate the effect of mature stages on quality of Rafito tomatoes (Lycopersicon esculentum Mill.) during storage at low temperature. Tomatoes grown in greenhouse were harvested at three different mature stages (turning, pink, and red), packaged with a 30-${\mu}m$-thick polyethylene film, and then stored at 5 and $10^{\circ}C$, respectively. The changes in firmness, soluble solids content (SSC), titratable acidity (TA), colour, lycopene content, decay, and chilling injury were measured on a weekly basis. After three weeks of storage, chilling injury and decay were found to have individually occurred at 5 and $10^{\circ}C$, respectively. As there was little change in quality at $5^{\circ}C$, it was concluded that red tomatoes could maintain their good quality for two weeks. The normal postharvest ripening was inhibited in the turning and pink tomatoes during storage at $5^{\circ}C$. The turning and pink tomatoes showed improved quality after two-week storage at $10^{\circ}C$. In particular, the turning fruits showed the highest firmness throughout the storage period. Furthermore, the red colour, SSC/TA, and lycopene content of the turning fruits reached the same levels as with the red fruits after two-week storage at $10^{\circ}C$. These results suggest that red tomatoes should be stored at $5^{\circ}C$ to inhibit decay, and that the optimum temperature for early-harvested tomato (turning and pink) is $10^{\circ}C$ for the ripening process after harvest.

Effect of WC and group IV Elements of Ti(C,N) on Cutting Performance in Turning (선삭시 Ti(C,N)계 서메트 공구의 WC와 IV족 원소 첨가가 절삭성능에 미치는 영향)

  • 박준석;김경재;권원태;강신후
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.10a
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    • pp.3-7
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    • 2001
  • In this study, the effect of WC and group IV elements on the cutting performance in turning is investigated. The composition of WC was changed from 5 to 20% to determine the effect of WC on the cutting performance of cermet tool. The more WC was added, the longer the tool life of the cermet tool was. The cermet with 20% WC showed the best fracture toughness. The cermet tool with 20% WC showed the best cutting performance among the various WC composition. The effect of group IV elements ; ZrC, ZrN and HfC was also investigated by adding each of them to manufacture the cermet tool with fixed 14% WC composition. The cermet with 1% group IV HfC and 14% WC showed the best cutting performance among the investigated cermet tools.

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The Development of Operating Standards for the Adjustment of Pedestrian Green Phasing at a Signalized Intersection (신호교차로에서 보행자신호 전시간 운영기준 설정을 위한 연구)

  • Lee Choul-Ki;Lee Seok;Shim Dae-Young;Kim Gyun-Jo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.2 no.1 s.2
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    • pp.41-52
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    • 2003
  • The purpose of this study was to test the effects of the pedestrian green signal adjustment on clearance of the turning vehicles impeding the through traffic flow at the signalized intersections, and thereby, suggest some operational criteria for adjustment of the pedestrian green signal. In order to test such effects, the pedestrian green time was adjusted so that it could started a few seconds later than the vehicle green time during peak hours, and thereby, the turning vehicle volume not cleared at the intersection was measured by extending the time gap by 2 seconds. (In general, the pedestrian green signal turns on at the same time as the vehicle green signal.) The results of this test can be summed up as follows; first, the longer the time gap was, the turning vehicle volume not cleared from the intersection decreased more. Second, in case there existed a storage space between intersection and crosswalk the effect of the turning vehicles on the through traffic flows was minimal. Third, at the pelican, the effect of the turning vehicles on the through traffic flow was minimal due to the structure of the intersection and the phase sequence. In conclusion, it was found that the adjustment of pedestrian green signal had the effect of enhancing the intersection operation. When adjusting the pedestrian green signal, it was deemed necessary to thoroughly survey the geometric structure of the intersection and collect the data on the turning traffic volume and thereby, apply the results of analysis flexibly to each intersection.

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Assessment of specific cutting energy characteristics during turning SM45C steel (SM45C의 선삭가공시 비절삭에너지 특성평가)

  • 이영문;양승한;최봉환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.1012-1015
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    • 2001
  • The purpose of this paper is to evaluate the specific cutting energy characteristics during turning SM45C steel. Using the orthogonal array method the specific cutting energy has been predicted. And the significance of the equation is checked by ANOVA test. Predicted values of specific cutting energy are well concide with the measured ones. When the feed rate becaomes larger than 0.5mm/rev, predicted specific cutting energy increases.

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Vibration Analysis of Rotary Compressors Considering the Coupled Effect of Motor (전동기의 연성을 고려한 로터리 압축기의 진동 해석)

  • 정의봉;황선웅;안세진;김정훈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1055-1060
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    • 2002
  • The noise and vibration of rolling piston-type compressors used in the most of the airconditional system is a serious and important problem occurred during turning on and off as well as during operating. To analyze the vibration occurred during turning on and oft, the vibration analysis of motor-compressor coupling is required. In this paper, through modeling of the motor, solving the force from the equations of motion of the moving parts and considering the stiffness of the rubber mounts, the analysis of vibration was performed.

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