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Prasad, Shailesh
- Studies of Seed Germination in Four Rhododendron Species of Garhwal Himalayas
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Indian Forester, Vol 138, No 3 (2012), Pagination: 284-287Abstract
Seed germination studies in four Rhododendron species were carried out in BOD incubator at 20°C ± 1°C temperature under continuous light as well as in open laboratory conditions at 25°C ± 2°C temperature. In BOD incubator, maximum 76.25% germination was recorded in the seeds of Rhododendron anthopogon followed by 61.5% in R. campanulatum and 59.25% in R. barbatum with 59.25% while minimum 53.5% was recorded in R. arboreum. However, in open lab conditions (25°C ± 2°C), maximum germination 56.5% was recorded in Rhododendron anthopogon followed by 47.5% in R. barbatumand minimum 41.0% in R. campanulatum. Highest number of seed per capsule was observed in R. campanulautum (900-1100) followed by R. arboreum (850-1000), R. barbatum (300-400) and R. anthopogon (350-450). Maximum seed length 2.93 mm and seed width 1 mm was observed in Rhododendron barbatum followed by R. campanulatum (2.04 and 0.63 mm) and R. arboreum (1.71 mm and 0.63 mm) while, minimum (1.04 mm and 0.47 mm) was recorded in R. anthopogon.Keywords
Rhododendron Spp., Germination Percentage, Germination Energy, Germination Value, Capsule Length And Width, Seed Length and Width, Seed Weight- Design, Development, Static and Flight Tests of Reverse Flow Multiple Nozzle Solid Rocket Motor with High Burn Rate Propellant
Abstract Views :176 |
PDF Views:85
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.