• Title/Summary/Keyword: bell

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Numerical analysis on the performance of centrifugal fans according to shapes of inlet bell-mouth in a refrigerator (입구 벨마우스 형상에 따른 냉장고 원심홴의 성능에 대한 수치적 분석)

  • Kim, Sang-Hyeon;Heo, Seung;Cheong, Cheol-Ung;Kim, Tae-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 한국소음진동공학회 2011년도 추계학술대회 논문집
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    • pp.737-742
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    • 2011
  • Because of complex structure of inlet and outlet flows, the performance of centrifugal fans used in a household refrigerator is affected by many parameters of duct system surrounding the fans. In this paper, the performance of a centrifugal fan is numerically analysed according to shapes of inlet bell-mouth. To improve performance of the centrifugal fan, some design parameters are selected for comparison. On a basis of these comparison, optimum shape of inlet bell-mouth is proposed to maximise the flow rate of the fan.

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T-sum of bell-shaped fuzzy intervals

  • Hong, Dug-Hun
    • 한국데이터정보과학회:학술대회논문집
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    • 한국데이터정보과학회 2006년도 추계 학술발표회 논문집
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    • pp.81-95
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    • 2006
  • The usual arithmetic operations on real numbers can be extended to arithmetical operations on fuzzy intervals by means of Zadeh's extension principle based on a t-norm T. A t-norm is called consistent with respect to a class of fuzzy intervals for some arithmetic operation if this arithmetic operation is closed for this class. It is important to know which t-norms are consistent with a particular type of fuzzy intervals. Recently Dombi and Gyorbiro proved that addition is closed if the Dombi t-norm is used with two bell-shaped fuzzy intervals. A result proved by Mesiar on a strict t-norm based shape preserving additions of LR-fuzzy intervals with unbounded support is recalled. As applications, we define a broader class of bell-shaped fuzzy intervals. Then we study t-norms which are consistent with these particular types of fuzzy intervals. Dombi and Gyorbiro's results are special cases of the results described in this paper.

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The Performance in Shell-and-Tube Heat Exchangers with Configuration and Surface Characteristics of Tube (Tube의 형상 및 표면특성에 의한 Shell-and-Tube 열교환기의 열전달 성능)

  • Kim, Sung-Il;Park, Ki-Ho;Chun, Won-Pyo
    • Proceedings of the KSME Conference
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2316-2321
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    • 2008
  • This paper presents an improved performance of heat transfer for shell-and-tube and thermal analysis based on the Bell-Delaware method for single tube. Heat transfer has been compared for a smooth tube, helical tube and surface-coated tube. In general, the results showed that properly designed helical tube and surface-coated tube offer a significant improvement in heat transfer. The numerical results derived from the Bell-Delaware method for the shell-side heat transfer coefficient were verified with experimental results. The thermal analysis aids significantly in the solution of the design problem.

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A Study on Comparison between the Vibration Characteristics of the King Songdok Bell and the Human Body (인체와 성덕대왕 신종의 진동 특성 비교 연구)

  • Jeon, Jong-Won;Chin, Yong-Ohk
    • The Transactions of the Korea Information Processing Society
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    • 제7권10호
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    • pp.3119-3127
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    • 2000
  • This paper is a study to find a new method of feature selection for vibrationof buman body by analyzing correlationof vibration between King Songdok Bell and Human body. The vibration characteristics are analyzed by matching body, vocal tract, diaphragm and asymmetrical clements of human body with Bell, resonator, hole in the ground and asymmetical elements. In the result, the characteristics of sound vibrationof King Songdok Bell is useful to apply it to vibration characteristics of human body because the vibration characteristics of ech elements is alike.

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Numerical Analysis of Belled Shaft Foundation in Thick Pusan Clays (대심도 부산점토에 적용된 종저말뚝(Belled Shaft foundation)의 수치해석 연구)

  • Rao, K.G.
    • Proceedings of the Korean Geotechical Society Conference
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    • 한국지반공학회 2006년도 춘계 학술발표회 논문집
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    • pp.530-535
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    • 2006
  • The Pusan clays are soft and thick deposits and in some places, they reach even up to 50-70m. So, the pile foundations are inevitable in almost all cases. But they are significantly expansive when the length of the pile reaches about 70m. In this study, a comprehensive parametric study has been carried out in order to reduce the pile length and number of piles required in turn the cost of the foundation for particular building. A belled shaft pile has been optimized for a typical soil profile using the PLAXIS (FEM code). These results have shown a new direction of the pile foundation in Pusan, Korea. The results including the variation of contact pressures at the bottom of the bell, optimization of the angle of the bell and height of the bell in terms of the diameter of the shaft. And also, the design curves have been generated so that they can be directly used for design of belled shaft foundations. However, the structural strength criterion is being checked in the concerned laboratory.

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The study on relation between ocular function and accommodative facility (시기능과 조절 용이성과의 관계 연구)

  • Park, Hyun-Ju
    • Journal of Korean Ophthalmic Optics Society
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    • 제10권4호
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    • pp.375-380
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    • 2005
  • To assess convergence and accommodation at a short distance, 92 selected subjects without any ocular diseases by apperatuses of visual chart(Shinnippon CT30) and phoropter(Shinnippon VT 10) at a short distance(40 cm) were tested upon MEM retinoscopy(Welch Allyn, USA). BELL retinoscopy(Welch Allyn, USA), binocular accommodative facility (${\pm}2.00$ D flipper. Bernell Co., USA), vergence facility(prism flipper, Bernell Co., USA). There were such test results as MEM retinoscopy(R/L)($+1.05{\pm}0.87/1.02{\pm}0.80$ D). BELL retinoscopy ($17.89{\pm}12.12/17.94{\pm}11.72cm$), binocular accommodative facility (R/G)($7.69{\pm}6.48cpm$). binocular accommodative facility(polaroid)($11.76{\pm}5.22cpm$), monocular accommodative facility(R/L) ($13.9{\pm}6.27/13.8{\pm}5.96cpm$), vergence facility($13.5{\pm}6.40cpm$).

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