Vikram Sarabhai Space Centre

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.

Correlation of binder mechanical properties with functionality type and molecular weight distribution for hydroxy-terminated polybutadienes: 13C-NMR and SEC studies

Abstract: Hydroxy-terminated polybutadiene (HTPB) liquid prepolymers (I-IX), with closely similar OH values, Mn, viscosity, and microstructure, were synthesized by H2O2-initiated free-radical polymerization of butadiene in an isopropanol–water solvent system. However, binders obtained by curing HTPB polymers showed wide variations in their sol content, cross-link density, and mechanical properties. These variations were atributed to the differences in functionality-type distribution (FTD) and molecular weight distribution (MWD) of the polymers. FTD was interpreted in terms of -type primary hydroxyls. [V/G] showed excellent linear correlation with the elongation at break (E) of the binders. The polymers exhibited bimodal MWD and this behavior was discussed in relation to two different initiation processes occurring. The high molecular weight fraction (Fh) of the various polymers was determined by reverse-phase HPLC and showed good correlation with E. The sol content and cross-link density of the binders also showed good correlation with the parameter V/GFh. The parameters [V/G] and Fh provide acceptance criteria for blending different batches of polymers for propellant formulations. © 1993 John Wiley & Sons, Inc.

The Cadmium Zinc Telluride Imager on AstroSat

Abstract: The Cadmium Zinc Telluride Imager (CZTI) is a high energy, wide-field imaging instrument on AstroSat. CZT's namesake Cadmium Zinc Telluride detectors cover an energy range from 20 keV to > 200 keV, with 11% energy resolution at 60 keV. The coded aperture mask attains an angular resolution of 17' over a 4.6 deg x 4.6 deg (FWHM) field of view. CZTI functions as an open detector above 100 keV, continuously sensitive to GRBs and other transients in about 30% of the sky. The pixellated detectors are sensitive to polarisation above ~100 keV, with exciting possibilities for polarisation studies of transients and bright persistent sources. In this paper, we provide details of the complete CZTI instrument, detectors, coded aperture mask, mechanical and electronic configuration, as well as data and products.