Mohanan, P; K G Nair; Stephen, Rodrigues(Department of Electronics, November , 1991)
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Abstract:
Design and development of a new feed -horn antenna
with low sidelobe levels is reported . The E-walls of this
antenna are fabricated with low -loss dielectric substrate , periodically
loaded with thin conducting strips . The antenna is found
to be simulating the radiation characteristics of metallic corrugated
horns . This can be an ideal substitute for metallic corrugated
horns with added advantages like light -weight and low
production cost.
K G Nair; Mohanan, P; Stephen, Rodrigues(Department of Electronics, 1991)
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Abstract:
Design and development of a new feed -horn antenna
with low sidelobe levels is reported . The E-walls of this
antenna are fabricated with low -loss dielectric substrate , periodically
loaded with thin conducting strips . The antenna is found
to be simulating the radiation characteristics of metallic corrugated
horns . This can be an ideal substitute for metallic corrugated
horns with added advantages like light -weight and low
production cost.
Ramakrishnan, K; Dr. Balakrishnan, K G(Cochin University of Science & Technology, 1991)
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Abstract:
Remote Data acquisition and analysing systems
developed for fisheries and related environmental studies
have been reported. It consists of three units. The first
one namely multichannel remote data acquisition system is
installed at the remote place powered by a rechargeable
battery. It acquires and stores the 16 channel environmental
data on a battery backed up RAM. The second unit
called the Field data analyser is used for insitue display
and analysis of the data stored in the backed up RAM. The
third unit namely Laboratory data analyser is an IBM
compatible PC based unit for detailed analysis and interpretation
of the data after bringing the RAM unit to the
laboratory. The data collected using the system has been
analysed and presented in the form of a graph. The system
timer operated at negligibly low current, switches on the
power to the entire remote operated system at prefixed time
interval of 2 hours.Data storage at remote site on low power battery
backedupRAM and retrieval and analysis of data using PC are
the special i ty of the system. The remote operated system takes about 7 seconds including the 5 second stabilization
time to acquire and store data and is very ideal for remote
operation on rechargeable bat tery. The system can store
16 channel data scanned at 2 hour interval for 10 days on
2K backed up RAM with memory expansion facility for 8K RAM.
Description:
Department of Electronics,
Cochin University of Science and Technology
Sunil K Narayanankutty(Gordon and Breach Science Publishers, December 10, 1991)
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Abstract:
Tear and wear properties of short kevlar fiber, thermoplastic polcurethane (TPU) composite with
respect to fiber loading-and fiber onentation has been studied and the fracture surfaces were examined
under scanning electron microscope (SEM). Tear strength first decreased up to 20 phr fiber loading
and then gradually increased with increasing fiber loading. Anisotropy in tear strength was evident
beyond a fiber loading of 20 phr. Tear fracture surface of unfilled TPU showed sinusoidal folding
characteristics of high strength matrix. At low fiber loading the tear failure was mainly due to fibermatrix failure whereas at higher fiber loading the failure occurred by fiber breakage. Abrasion loss
shows a continuous rise with increasing fiber loading, the loss in the transverse orientation of fibers
being higher than that in the longitudinal orientation. The abraded surface showed lone cracks and
ridges parallel to the direction of abrasion indicating an abrasive wear mechanism. In the presence of
fber the abrasion loss was mainly due to fiber low.
Thomas, Baby; Sathianandan, K; Nampoori, V P N; Vallabhan, C P G; Ramachandran, T(American Institute of Physics, September , 1991)
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Abstract:
A high power Nz laser of the double-Blumlein type having a modified gas flow system,
electrode configuration, and discharge geometry with minimum inductance is described. By
incorporating a triggere’d-pressurized spark gap switch, arc-free operation was achieved
for a wide E/P range. The device gives a peak power in excess of 700 kW with a FWHM of
3 ns and an efficiency of 0.51%, which is remarkably high for a pulsed nitrogen laser
system. The dependence of output power on parameters such as operating pressure, voltage,
and repetition rate are discussed.
The design and development of an L-band printed dipole antenna.
optimized for wide-band applications near first resonance, is reported.
This design has achieved more than 48% impedance bandwidth
(VSWR 2:1), without degrading its overall radiation efficiency
Rani, Joseph; Jayamma,Francis; George,K E(Pergamon Press Ltd, December 18, 1991)
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Abstract:
The effects of modifying blends of poly(vinyl chloride) (PVC) with linear low density
polyethylene (LLDPE) by means of acrylic acid, maleic anhydride, phenolic resins and p-phenylene
diamine were investigated. Modification by acrylic acid and maleic anhydride in the presence of dicumyl
peroxide was found to be the most useful procedure for improving the mechanical behaviour and adhesion
properties of the blend. The improvement was found to be due mainly to the grafting of the carboxylic
acid to the polymer chains; grafting was found to be more effective in LLDPE/PVC blends than in pure
LLDPE.