Vikram Sarabhai Space Centre

About: Vikram Sarabhai Space Centre is a facility organization based out in Thiruvananthapuram, India. It is known for research contribution in the topics: Aerosol & Ultimate tensile strength. The organization has 2092 authors who have published 3058 publications receiving 47975 citations. The organization is also known as: VSSC.

Response of the equatorial ionosphere in the Indian (midnight) sector to the severe magnetic storm of July 15, 2000

Abstract: [1] During the severe magnetic storm of July 15, 2000, an impulsive and remarkably large downward movement of F region occurred simultaneously at locations throughout the equatorial region (dip 0.3–20°N) in the Indian sector, in close association with episodes of rapid ring current intensification. The abnormal midnight descent of equatorial F region (maximum amplitude close to the magnetic equator, 215 km/hr) indicative of a short-lived westward electric field disturbance (peak amplitude ≈4.6 mV/m) is interpreted as the signature of prompt penetration electric fields associated primarily with impulsive ring current injections. The westward electric field disturbance in the Indian (midnight) sector occurred near simultaneous with the eastward electric field disturbances in the dusk sector, reported by Basu et al. [2001a]. Moreover, the prompt electric field penetration to the magnetic equator both in the dusk and midnight sectors occurred in an environment already under the influence of ionospheric disturbance dynamo (IDD) electric fields, illustrating the profound manner in which the equatorial F region plasma dynamics can get modified globally during the main phase of severe magnetic storms.

A two‐noded locking–free shear flexible curved beam element

Abstract: A new two-noded shear flexible curved beam element which is impervious to membrane and shear locking is proposed herein. The element with three degrees of freedom at each node is based on curvilinear deep shell theory. Starting with a cubic polynomial representation for radial displacement (w), the displacement field for tangential displacement (u) and section rotation (θ) are determined by employing force-moment and moment-shear equilibrium equations. This results in polynomial displacement field whose coefficients are coupled by generalized degrees of freedom and material and geometric properties of the element. The procedure facilitates quartic polynomial representation for both u and θ for curved element configurations, which reduces to linear and quadratic polynomials for u and θ, respectively, for straight element configuration. These coupled polynomial coefficients do not give rise to any spurious constraints even in the extreme thin regimes, in which case, the present element exhibits excellent convergence to the classical thin beam solutions. This simple C0 element is validated for beam having straight/curved geometries over a wide range of slenderness ratios. The results indicates that performance of the element is much superior to other elements of the same class. Copyright © 1999 John Wiley & Sons, Ltd.