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Institution

Vikram Sarabhai Space Centre

FacilityThiruvananthapuram, 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
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Journal ArticleDOI
TL;DR: In this article, Magnesium alloy AZ31 was caliber rolled at different temperatures viz. 523K, 573K, 623K 623 K, 673K 673k, 613K and 723K imposing a total cumulative reduction of 92% and a cumulative strain of 2.6.

30 citations

Journal ArticleDOI
TL;DR: In this article, the authors examined the properties of background aerosols and their dependence on meteorological, geographical and human influence using measured spectral aerosol optical depth (AOD), total mass concentration (M T ) and derived number size distribution (NSD) over two distinct coastal locations of Antarctica; Maitri (70° S, 12° E, 123 m m.s.l.
Abstract: . The properties of background aerosols and their dependence on meteorological, geographical and human influence are examined using measured spectral aerosol optical depth (AOD), total mass concentration ( M T ) and derived number size distribution (NSD) over two distinct coastal locations of Antarctica; Maitri (70° S, 12° E, 123 m m.s.l.) and Larsemann Hills (LH; 69° S, 77° E, 48 m m.s.l.) during southern hemispheric summer of 2007–2008 as a part of the 27th Indian Scientific Expedition to Antarctica (ISEA) during International Polar Year (IPY). Our investigations showed comparable values for the mean columnar AOD at 500 nm over Maitri (0.034±0.005) and LH (0.032±0.006) indicating good spatial homogeneity in the columnar aerosol properties over the coastal Antarctica. Estimation of Angstrom exponent α showed accumulation mode dominance at Maitri (α~1.2±0.3) and coarse mode dominance at LH (0.7±0.2). On the other hand, mass concentration ( M T ) of ambient aerosols showed relatively high values (≈8.25±2.87 μg m −3 ) at Maitri in comparison to LH (6.03±1.33 μg m −3 ).

30 citations

Journal ArticleDOI
TL;DR: In this article, a polynomial chaos based stochastic finite element methodology is developed for uncertainty quantification and failure probability estimation in CFRP laminated composite plates, which is based on modelling the spatial inhomogeneities in the material properties as 2D non-Gaussian random fields and representing them as PC expansions.

30 citations

Journal ArticleDOI
TL;DR: In this article, the complex three-dimensional flowfield produced by secondary injection of hot gases in a rocket nozzle for thrust vector control is analyzed by solving unsteady three dimensional Euler equations with appropriate boundary conditions, and various system performance parameters like secondary jet amplification factor and axial thrust augmentation are deduced by integrating the nozzle wall pressure distributions obtained as part of the flowfield solution.
Abstract: The complex three-dimensional flowfield produced by secondary injection of hot gases in a rocket nozzle for thrust vector control is analyzed by solving unsteady three-dimensional Euler equations with appropriate boundary conditions. Various system performance parameters like secondary jet amplification factor and axial thrust augmentation are deduced by integrating the nozzle wall pressure distributions obtained as part of the flowfield solution and compared with measurements taken in actual static tests. The agreement is good within the practical range of secondary injectant flow rates for thrust vector control applications.

30 citations

Journal ArticleDOI
TL;DR: In this article, the authors present simultaneous observations of temporal and spatial variability of total electron content (TEC) and GPS amplitude scintillations on L 1 frequency (1.575 GHz) during the time of equatorial spread F (ESF) while the MST radar (53 MHz) located at Gadanki (13.5° N, 79.2° E, Dip latitude 6.3° N), a low latitude station, made simultaneous observations.
Abstract: . In this paper, we present simultaneous observations of temporal and spatial variability of total electron content (TEC) and GPS amplitude scintillations on L1 frequency (1.575 GHz) during the time of equatorial spread F (ESF) while the MST radar (53 MHz) located at Gadanki (13.5° N, 79.2° E, Dip latitude 6.3° N), a low latitude station, made simultaneous observations. In particular, the latitudinal and longitudinal extent of TEC and L-band scintillations was studied in the Indian region for different types of ESF structures observed using the MST radar during the low solar activity period of 2004 and 2005. Simultaneous radar and GPS observations during severe ESF events in the pre-midnight hour reveal that significant GPS L band scintillations, depletions in TEC, and the double derivative of the TEC index (DROTI), which is a measure of fluctuations in TEC, obtained at low latitudes coincide with the appearance of radar echoes at Gadanki. As expected, when the irregularities reach higher altitudes as seen in the radar map during pre-midnight periods, strong scintillations on an L-band signal are observed at higher latitudes. Conversely, when radar echoes are confined to only lower altitudes, weak scintillations are found and their latitudinal extent is small. During magnetically quiet periods, we have recorded plume type radar echoes during a post-midnight period that is devoid of L-band scintillations. Using spectral slopes and cross-correlation index of the VHF scintillation observations, we suggest that these irregularities could be "dead" or "fossil" bubbles which are just drifting in from west. This scenario is consistent with the observations where suppression of pre-reversal enhancement (PRE) in the eastward electric field is indicated by ionosonde observations of the height of equatorial F layer and also occurrence of low spectral width in the radar observations relative to pre-midnight period. However, absence of L-band scintillations during post-midnight event, when radar observed plume like structures and scintillations were recorded on VHF band, raises questions about the process of evolution of the irregularities. A possible explanation is that whereas small scale (~3 m) irregularities are generated through secondary waves that grow on the walls of km scale size irregularities, in this case evolution of the Rayleigh-Taylor instability itself did not extend to irregularities of scale sizes of a few hundred meters that produce scintillation on a L-band signal.

30 citations


Authors

Showing all 2111 results

NameH-indexPapersCitations
M. Santosh103134449846
Sabu Thomas102155451366
S. Suresh Babu7049817113
K. Krishna Moorthy542639749
Sathianeson Satheesh5317211099
M. Y. Hussaini4920716794
J.R. Banerjee441465620
C. P. Reghunadhan Nair371814825
K. N. Ninan361594156
Anil Bhardwaj352304527
Ivatury S. Raju331216626
Venkata Sai Kiran Chakravadhanula321023011
P.K. Sinha321182918
J.-P. St.-Maurice311133446
Subramaniam Gopalakrishnan281232951
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202313
202230
2021186
2020160
2019149
2018136