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.

Finite element analysis with an improved failure criterion for composite wind turbine blades

Abstract: Some interesting studies are made in this paper on the life management of a composite wind turbine blade. It presents the details of finite element modeling and validation, blade response under service loading conditions, power coefficient evaluation for the optimum design parameters of the blade configuration, development of failure envelope and fatigue life estimations. Finite element analysis results are found to be in good agreement with existing test results on a typical composite blade configuration. The failure envelope generated from the present modified failure criterion correlates well with the test results on different composite materials. The procedure adopted in this paper can be utilized for optimum design of large size composite wind turbine blades.

Size segregated aerosol mass concentration measurements over the Arabian Sea during ICARB

Abstract: Mass concentration and mass size distribution of total (composite) aerosols near the surface are essential inputs needed in developing aerosol models for radiative forcing estimation as well as to infer the environment and air quality. Using extensive measurements onboard the oceanographic research vessel, Sagar Kanya, during its cruise SK223B in the second phase of the ocean segment of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB), the spatial distribution of the mass concentration and mass size distribution of near-surface aerosols are examined for the first time over the entire Arabian Sea, going as far as 58°E and 22°N, within a span of 26 days. In general, the mass concentrations (MT ) were found to be low with the mean value for the entire Arabian Sea being 16.7 ± 7 μg m−3; almost 1/2 of the values reported in some of the earlier campaigns. Coarse mode aerosols contributed, on an average, 58% to the total mass, even though at a few pockets accumulation mode contribution dominated. Spatially, significant variations were observed over central and northern Arabian Sea as well as close to the west coast of India. In central Arabian Sea, even though the MT was quite low, contribution ofs accumulation aerosols to the total mass concentration was greater than 50%. Effective radius, a parameter important in determining scattering properties of aerosol size distribution, varied between 0.07 and 0.4 μm with a mean value of 0.2 μm. Number size distributions, deduced from the mass size distributions, were approximated to inverse power-law form and the size indices (ν) were estimated. It was found to vary in the range 3.9 to 4.2 with a mean value of 4.0 for the entire oceanic region. Extinction coefficients, estimated using the number-size distributions, were well-correlated with the accumulation mode mass concentration with a correlation coefficient of 0.82.

Distillation technology and need of simultaneous design and control: A review

Abstract: During the whole of history, distillation has been the most extensive separation method. Regardless of its flexibility and simplicity, distillation technology is highly energy consuming. Modernistic distillation technologies based on intensification process has more ascendency than its conventional, not in terms of less energy consumption but it reduces the capital investment cost and improved efficiency. In order to meet the demands of modern society, a drastic development in the field of separation is required. Here this article first pointing towards the overview of latest trends in distillation technology with process intensification principles. In order to meet the control of modern chemical process, simultaneous design and control is proposed over the conventional design and control methods. Second, the article is pointing to various optimisation techniques used for simultaneous design and control of chemical processes. Significant development in the area of simultaneous design and control is categorised into two. 1) Controllability indicator based foundation 2) optimisation based foundation. In the simultaneous design and control of chemical process, first discussion started with the motivation and significance of simultaneous design and control based optimisation technique, then pointing towards the existing methodologies with theoretical algorithms and its merits and demerits.

Shape memory characterization of polytetra methylene oxide/poly (acrylic acid-co-acrylonitrile) complexed gel

Abstract: Polymer gels of poly(acrylic acid-co-acrylonitrile) [p(AA-co-AN)] of varying compositions were synthesized and complexed with polytetramethylene oxide (PTMO) to get PTMO/p(AA-co-AN) complexed gels. The complexation occurred through H-bonding of carboxyl group of acrylic acid with ether group of PTMO. The PTMO/p(AA-co-AN) gels were characterized by DSC, DMTA and swelling ratio. Their shape memory property was evaluated by bending tests. The swelling ratio of [p(AA-co-AN)] in PTMO (as solvent) increased and Tg of the complexed gel diminished with enhancement in the acrylic acid-content in the copolymer. The modulus ratio (Eg/Er) increased with the acrylic acid content, which is conducive to better shape memory and shape recovery properties of the gels. The influence of the copolymer composition on the swelling ratio, Tg, dynamic mechanical and the shape memory properties of the complexes is examined and presented. The gels showed a shape recovery of >90%, which increased with the acrylic acid content in the copolymer.