Institution
Vikram Sarabhai Space Centre
Facility•Thiruvananthapuram, India•
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.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, a fixed step-size fourth-order Runge-Kutta-Gill method is employed for numerical integration of the canonical equations with Earth's oblateness.
Abstract: This paper concerns with the study of KS uniformly regular canonical elements with Earth's oblateness. These elements, ten in number, are all constant in the unperturbed motion and even in the perturbed motion, the substitution is straightforward and elementary due to the transformation laws being explicit and closed expression. By utilizing the recursion formulas of Legendre's polynomials, we are able to include any number of Earth's zonal harmonics J
n in the package and also economize the computations. A fixed step-size fourth-order Runge-Kutta-Gill method is employed for numerical integration of the canonical equations. Utilizing 5 test cases covering a large range of semimajor axis and eccentricity, we have carried out computations to study the effects of Earth's zonal harmonics (up to J
36) and integration step-size variation. Bilinear relations and energy equation are used for checking the accuracies of numerical integration. From the application point of view, the package is utilized to study the behaviour of 900 km height near-circular sun-synchronous satellite orbit over a longer duration of 220 days time (nearly 3078 revolutions) and the necessity of including more number of Earth's zonal harmonic terms is noticed. The package is also used to study the effect of higher zonal harmonics on three 900 km height near-circular orbits with inclinations of 60, 63.2, and 65 degrees, by including Earth's zonal harmonics up to J
24. The mean eccentricity (e
m) is found to have long-periods of 459.6, 6925.1 and 1077.6 days, respectively. Sharp changes in the variation of Ωm near the minima to em are noticed. The values of Ω
m are found to be very near to +-90 degrees at the extrema of em. The same orbit is employed to study the effect of variation of inclination from 0 to 180 degrees on long-period (T) of eccentricity with J
2 to J
24 terms. T is found to increase rapidly as we proceed towards the critical inclinations.
19 citations
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TL;DR: In this paper, it is shown that the E region signals are not directly coupled with the F region irregularities just overhead, but linked with the instability processes over the magnetic equator through the magnetic field lines.
Abstract: [1] Simultaneous observations of E and F region irregularities made using the Gadanki MST radar are presented. The observations show that the E region echoes weaken or disappear during the growth phase of the topside F region irregularities. Unlike Jicamarca observations, no valley region echoes are observed during this phase. It is shown that the weakening or disappearance of E region signals are not directly coupled with the F region irregularities just overhead, but linked with the instability processes over the magnetic equator through the magnetic field lines. It is proposed that the fringe fields present in the valley region in association with the equatorial F region plasma bubbles, in the presence of appropriate background electric field conditions, are responsible candidates. It is shown that these fringe fields and the electric fields associated with the irregularities in the valley region can map to the low latitude E region and thereby inhibit the growth of the E region instability processes as revealed by the Gadanki radar observations.
19 citations
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TL;DR: An analysis of in-situ measured near-surface CH4, column averaged and upper tropospheric CH4 retrieved by Atmospheric Infrared Sounder onboard Earth Observing System (EOS)/Aqua which gives insight into the vertical distribution of the CH4 over the location is presented.
19 citations
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TL;DR: In this paper, the results revealed that corrosive wear at the root fillet caused pitting, intense localised plastic strain and folds, leading to crack formation, and the advance of the crack took place under the successive stress repetitions to which the gear was subjected, causing the tooth to fail by fatigue.
19 citations
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TL;DR: In this paper, several simultaneous interpenetrating networks (IPN) of castor oil polyurethane (COPUN) and polystyrene divinyl benzene (PSN) were synthesized under conditions where the free radical polymerization of styrene and the crosslinking reaction of Castor oil and toluene diisocyanate progress at comparable rates.
Abstract: Several simultaneous interpenetrating networks (IPN) of castor oil polyurethane (COPUN) and polystyrene divinyl benzene (PSN) were synthesized under conditions where the free radical polymerization of styrene and the crosslinking reaction of castor oil and toluene diisocyanate progress at comparable rates. Comparison of the mechanical properties and crosslink density of the COPUN and COPUN/PSN-IPNs indicates a marginal increase in tensile strength and crosslink density from COPUN to 60COPUN/40 PSN IPN. IPN samples prepared with further increased PSN content show steady decrease in the above properties. This reversal of the expected trend was attributed to the possible greater molecular interpenetration achieved due to similar gelation times with resultant extension of chains and increase in free volume between crosslinks. This was further confirmed from thermogravimetric data on the initial stages of decomposition of the IPNs.
19 citations
Authors
Showing all 2111 results
Name | H-index | Papers | Citations |
---|---|---|---|
M. Santosh | 103 | 1344 | 49846 |
Sabu Thomas | 102 | 1554 | 51366 |
S. Suresh Babu | 70 | 498 | 17113 |
K. Krishna Moorthy | 54 | 263 | 9749 |
Sathianeson Satheesh | 53 | 172 | 11099 |
M. Y. Hussaini | 49 | 207 | 16794 |
J.R. Banerjee | 44 | 146 | 5620 |
C. P. Reghunadhan Nair | 37 | 181 | 4825 |
K. N. Ninan | 36 | 159 | 4156 |
Anil Bhardwaj | 35 | 230 | 4527 |
Ivatury S. Raju | 33 | 121 | 6626 |
Venkata Sai Kiran Chakravadhanula | 32 | 102 | 3011 |
P.K. Sinha | 32 | 118 | 2918 |
J.-P. St.-Maurice | 31 | 113 | 3446 |
Subramaniam Gopalakrishnan | 28 | 123 | 2951 |