• Title/Summary/Keyword: rigidity

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The Effect of Structural Factors on the Torsional Rigidity of Yarns

  • Park, Jung Whan
    • Fashion & Textile Research Journal
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    • v.2 no.5
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    • pp.437-442
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    • 2000
  • In this paper, in order to examine the torsional behaviour of twisted yarn closely, the torsional rigidity would be derived in terms of physical and mechanical characteristics of its constituent fibers and yarn structural parameters by energy-method. And the propriety of the theory will be discussed by comparing with experimental results. The torsional rigidity of yarn in both experimental and theoretical results decreases with surface helix angle increases. But the experimental values are more higher than those of the theoretical ones.

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Buckling Analysis for Single Layer Latticed Domes considering the Change of Joint Rigidity (접합부 강성변화를 고려한 단층 래티스 돔의 좌굴해석)

  • 이후진;권택진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.337-344
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    • 2001
  • This paper is concerned with the change of joint rigidity in estimating the degree of semi-rigidity of connections and the buckling load in a single layer latticed dome. The estimations are based on information about the ratio for the rotational stiffness of the connection to the flexural stiffness of the member and the minimum eigenvalue of a structure for pinned, semi-rigid and completely rigid cases, respectively. Connection characteristics are reflected in the ratio control of joint rigidity for the DOFs to be related using the spring element by FEM.

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SOME RIGIDITY CHARACTERIZATIONS OF EINSTEIN METRICS AS CRITICAL POINTS FOR QUADRATIC CURVATURE FUNCTIONALS

  • Huang, Guangyue;Ma, Bingqing;Yang, Jie
    • Bulletin of the Korean Mathematical Society
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    • v.57 no.6
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    • pp.1367-1382
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    • 2020
  • We study rigidity results for the Einstein metrics as the critical points of a family of known quadratic curvature functionals involving the scalar curvature, the Ricci curvature and the Riemannian curvature tensor, characterized by some pointwise inequalities involving the Weyl curvature and the traceless Ricci curvature. Moreover, we also provide a few rigidity results for locally conformally flat critical metrics.

RIGIDITY CHARACTERIZATIONS OF COMPLETE RIEMANNIAN MANIFOLDS WITH α-BACH-FLAT

  • Huang, Guangyue;Zeng, Qianyu
    • Journal of the Korean Mathematical Society
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    • v.58 no.2
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    • pp.401-418
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    • 2021
  • For complete manifolds with α-Bach tensor (which is defined by (1.2)) flat, we provide some rigidity results characterized by some point-wise inequalities involving the Weyl curvature and the traceless Ricci curvature. Moveover, some Einstein metrics have also been characterized by some $L^{\frac{n}{2}}$-integral inequalities. Furthermore, we also give some rigidity characterizations for constant sectional curvature.

LOCAL TIMES OF GALACTIC COSMIC RAY INTENSITY MAXIMUM AND MINIMUM IN THE DIURNAL VARIATION (우주선 세기 일변화 최대 및 최소 지방시)

  • Oh Su-Yeon;Yi Yu
    • Journal of Astronomy and Space Sciences
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    • v.23 no.2
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    • pp.117-126
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    • 2006
  • The Diurnal variation of galactic cosmic ray (GCR) flux intensity observed by the ground Neutron Monitor (NM) shows a sinusoidal pattern with the amplitude of $1{\sim}2%$ of daily mean. We carried out a statistical study on tendencies of the local times of GCR intensity daily maximum aad minimum. To test the influences of the solar activity and the location (cut-off rigidity) on the distribution in the local times of maximum and minimum GCR intensity, we have examined the data of 1996 (solar minimum) and 2000 (solar maximum) at the low-latitude Haleakala (latitude: 20.72 N, cut-off rigidity: 12.91 GeV) and the high-latitude Oulu (latitude: 65.05 N, cut-off rigidity: 0.81 GeV) NM stations. The most frequent local times of the GCR intensity daily maximum and minimum come later about $2{\sim}3$ hours in the solar activity maximum year 2000 than in the solar activity minimum you 1996. Oulu NM station whose cut-off rigidity is smaller has the most frequent local times of the GCR intensity maximum and minimum later by $2{\sim}3$ hours from those of Haleakala station. This feature is more evident at the solar maximum. The phase of the daily variation in GCR is dependent upon the interplanetary magnetic field varying with the solar activity and the cut-off rigidity varying with the geographic latitude.