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Sreejith, K.
- Molecular Phylogeny and Genetic Analysis of Green Leafhopper - Nephotettix Virescens (Distant) Using Mitochondrial COI Gene
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Authors
Affiliations
1 Division of Molecular Biology, Department of Zoology, University of Calicut, Kerala, 673635, IN
1 Division of Molecular Biology, Department of Zoology, University of Calicut, Kerala, 673635, IN
Source
Indian Journal of Science and Technology, Vol 8, No 1 (2015), Pagination: 61-64Abstract
Accurate and rapid diagnosis of taxa, is of crucial importance to quarantine, pest management and analysis. Advances in DNA technology has resulted in an exceedingly vary of molecular techniques which might be employed in phylogenetically focussed approaches. Use of DNA sequence data derived from region of mitochondrial cytochrome oxidase I gene (mtCOI) has been widely used to estimate phylogenetic relationships at different taxonomic levels across insects. The present study investigates the molecular evolution of the Nephotettix virescens using COI gene (DDBJ accession No. AB976528; ENA accession No. LM994675) and its usefulness for reconstructing phylogenetic relationships within and among the leafhopper species.Keywords
DNA Sequencing, Leafhopper, Molecular Evolution, Mitochondrial COI, Nephotettix Virescens, Phylogenetics.- Design, Development, Static and Flight Tests of Reverse Flow Multiple Nozzle Solid Rocket Motor with High Burn Rate Propellant
Abstract Views :176 |
PDF Views:82
Authors
K. Sreejith
1,
Shailesh Prasad
1,
R. Bagavathiappan
1,
C. Prasanth
1,
R. Jeenu
1,
J. Paul Murugan
1,
Thomas Kurian
1,
N. Mansu
1,
R. Harikrishnan
1,
G. Levin
1,
V. Eswaran
1
Affiliations
1 Solid Propulsion and Research Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram 695 022, IN
1 Solid Propulsion and Research Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram 695 022, IN
Source
Current Science, Vol 120, No 1 (2021), Pagination: 116-121Abstract
The Vikram Sarabhai Space Centre, Thiruvananthapuram has developed a special purpose motor for Human Spaceflight Programme with four reverse flow nozzles, having cant angle of 149°, termed as Lowaltitude Escape Motor (LEM). This is a high-thrust short-duration motor having specific envelope constraints. New high burn rate propellant has been developed to achieve the specific mission requirements. In the design, emphasis has been given to smooth turning of internal flow, avoiding sharp edges and corners, to the specified cant angle. It has to satisfy the thermal as well as structural design requirements for the multiple nozzle openings provided, containing itself to minimum external projections and envelope. Since four ellipsoidal-shaped cut-outs from the chamber cause high stress concentrations, welding or some other joining methods are not preferable. The nozzle hardware has to be machined out of 15CDV6 steel forging with high precision. The motor is tested in the vertical mode in order to avoid exhaust gas hitting on the ground and getting deflected back to the motor. This calls for extensive thermal protection requirements for both test stand and motor subsystems. A solid rocket motor with four reverse flow nozzles has been designed, realized and twice static tested successfully. The intricacies involved in the development of LEM are presented in this article.Keywords
Launch Escape System, Manned Mission, Multiple Nozzles, Reverse Flow, Solid Rocket Motors.References
- McCarthy Jr, J. F., Ian Dodds, J. and Crowder, R. S., Development of the Apollo Launch Escape System. J. Spacecraft Aerosp. Res. Central, 1968, 5(8), 927–931.
- Goodwin, J. L., Development of the mark 22 mod 4. Naval Ordinance Station Report. AIAA-84-1417, AIAA/SAE/ASME 20th Joint Propulsion Conference, Cincinnati, Ohio, 11–13 June 1984.
- Wong, E. Y., Solid rocket nozzle design summary. Compiled under NASA contract NAS3-10296, Sacramento, California, 23 April 1968.