• Title/Summary/Keyword: ideal lift

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Effects of Port Shape on Steady Flow Characteristics in an SI Engine with Semi-Wedge Combustion Chamber (2) - Velocity Distribution (2) (반 쐐기형 연소실을 채택한 SI 기관에서 포트형상이 정상유동 특성에 미치는 영향 (2) - 유속분포 (2))

  • Yoon, Inkyoung;Ohm, Inyong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.2
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    • pp.97-107
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    • 2017
  • This study is the second investigation on the steady flow characteristics of an SI engine with a semi-edge combustion chamber as a function of the port shape with varying evaluation positions. For this purpose, the planar velocity profiles were measured from 1.75B, 1.75 times of bore position apart from the bottom of head, to 6.00B positions using particle - image velocimetry. The flow patterns were examined with both a straight and a helical port. The velocity profiles, streamlines, and centers of swirl were almost the same at the same valve lift regardless of the measuring position, which is quite different from the case of the pent-roof combustion chamber. All the eccentricity values of the straight port were out of distortion criterion 0.15 through the lifts and the position. However, the values of the helical port exceeded the distortion criterion by up to 4 mm lift, but decreased rapidly above the 3.00B position and the 5 mm lift. There always existed a relative offset effect in the evaluation of the swirl coefficient using the PIV method due to the difference of the ideal impulse swirl meter velocity profile assumption, except for the cylinder-center-base estimation that was below 4 mm of the straight port. Finally, it was concluded that taking the center as an evaluation basis and the assumption about the axial velocity profile did not have any qualitative effect on swirl evaluation, but affected the value owing to the detailed profile.

Transiting test method for galloping of iced conductor using wind generated by a moving vehicle

  • Guo, Pan;Wang, Dongwei;Li, Shengli;Liu, Lulu;Wang, Xidong
    • Wind and Structures
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    • v.28 no.3
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    • pp.155-170
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    • 2019
  • This paper presents a novel test method for the galloping of iced conductor using wind generated by a moving vehicle which can produce relative wind field. The theoretical formula of transiting test is developed based on theoretical derivation and field test. The test devices of transiting test method for aerodynamic coefficient and galloping of an iced conductor are designed and assembled, respectively. The test method is then used to measure the aerodynamic coefficient and galloping of iced conductor which has been performed in the relevant literatures. Experimental results reveal that the theoretical formula of transiting test method for aerodynamic coefficient of iced conductor is accurate. Moreover, the driving wind speed measured by Pitot tube pressure sensors, as well as the lift and drag forces measured by dynamometer in the transiting test are stable and accurate. Vehicle vibration slightly influences the aerodynamic coefficients of the transiting test during driving in ideal conditions. Results of transiting test show that the tendencies of the aerodynamic coefficient curve are generally consistent with those of the wind tunnel tests in related studies. Meanwhile, the galloping is fairly consistent with that obtained through the wind tunnel test in the related literature. These studies validate the feasibility and effectiveness of the transiting test method. The present study on the transiting test method provides a novel testing method for research on the wind-resistance of iced conductor.

A Study on the Effect of Popular Culture in Modern Fashion -Focused on the Fashion Icon- (현대 패션에 나타나는 대중문화의 영향에 관한 연구 -Fashion Icon을 중심으로-)

  • Kim, Young-Sam
    • Journal of the Korean Society of Costume
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    • v.56 no.7 s.107
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    • pp.58-67
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    • 2006
  • This study of popular culture is in based on an academic point of view and based thereon an investigation of popular culture from a fashion standpoint follows. This study is to suggest that the popular culture theory can be a basic framework to examine the characteristics of fashion Icon and to verify that the characteristics of Fashion Icon is similar to the codes of the popular culture of today, This study considers the characteristics of popular culture as commercialism, mass-media relationship and a symbolic interaction. The images of movie stars projected through diverse entertainment media are the very fashion icons and strong role models that are copied by consumers. Now, the public take the lead in cultural industry, and they create new images as positive receivers of the images of fashion icons, not as mere imitators or followers. Fashion irons have contributed to diversifying the styles of ideal feminine beauty, and their lift pattern and image are one of the major sources to stir up the imagination and inspiration of people. Thus, the times, fashion and entertainment media have continued to evolve, closely affecting one another, and fashion icons play a role of fashion leader, through entertainment media, who takes the initiative in mass fashion without just being confined to the field of entertainment. This study meaningful from the aspect that discussion of popular culture has been placed in a position that recognizes the entity of and interest in popular culture. through this study, I hope that the scope of interest in Fashion design will expand and that approaches to popular culture will become more diversified.

Forehead Lift using Non-endoscopic Myotomy (내시경을 사용하지 않은 근절개술을 이용한 전두거상술)

  • Han, Ki Hwan;Jung, Young Jin;Kim, Hyun Ji;Kim, Jun Hyung;Son, Dae Gu
    • Archives of Plastic Surgery
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    • v.33 no.1
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    • pp.80-86
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    • 2006
  • The challenge of accurately predicting eyelid height after blepharoptosis surgery is well-known problem even in complete hands. From May 1988 to December 2004, authors reviewed 182 cases(240 eyes) of blepharoptosis corrected by frontalis muscle transfer or levator resection and had experienced 10 cases(15 eyelids) of early reoperation around the first week. The period from initial operation to reoperation are between six to eight days and mean period is seven days. Initial operative procedures were frontalis muscle transfer in 3 cases(4 eyelids) and levator resection in 7 cases(11 eyelids). Follow up period ranged from 6 months to 16 years. Early adjusting surgery was performed in accordance with the preoperative and postoperative degree of ptosis of patient and by previous operative technique. The results are evaluated according to the criteria of an ideal correction by Souther and Jordan. Seven patients have good or satisfactory results(less than 1 mm asymmetry, good in 5 cases and satisfactory in 2 cases). Three patients(5 eyelids) recorded as poor results(more than 2 mm asymmetry). Even if early or late reoperation can be effective in correcting unsatisfactory results after correction of blepharoptosis, early reoperation may lead to better results than late reoperation because early reoperation can offer a reduction in time to final result, the ease with which it is performed and potential cost savings. The experience of surgeon is also important factor for the treat ment of recurred blepharoptosis.

Numerical Analysis of Gravity Current Flow past Subsea Pipe above a Scour (세굴된 해저 파이프 주위 중력류의 유동 해석)

  • Jung, Jae Hwan;Yoon, Hyun Sik
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.7
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    • pp.892-899
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    • 2016
  • Gravity current flow past a subsea pipe above a scour based on computational fluid dynamics. For comparison, gravity current flow over pipe above a smooth bed also calculated, this configuration conventionally employed to consider the scour effect from an ideal approach. Interestingly, there different flow features and hydrodynamic forces between the scour and smooth bed cases. These results indicate that realistic conditionvery important investigatthe scour effect on gravity current flow around subsea pipe.