National Aerospace Laboratories

About: National Aerospace Laboratories is a facility organization based out in Bengaluru, India. It is known for research contribution in the topics: Coating & Corrosion. The organization has 1838 authors who have published 2349 publications receiving 36888 citations.

Nose Bluntness for Side-Force Control on Circular Cones at High Incidence

Abstract: An experimental investigation has been car ked out to study the effect of nose bluntness on the characteristics of vortex asymmetry and induced side forces on slender cone models at low speeds. Two cone models with semi-apex angles of 8 and 12 deg were utilized, and on each model nose bluntness was varied up to 20% (based on base diameter).Measurements made consisted of six-component balance loads over a Widerange of Reynolds number from 0.4 x 10(6) to 5.4 x 10(6). The results show that the onset of vortex asymmetry with nose blunting correlates with geometrical parameters and is practically independent of Reynolds number. The (maximum) side-force levels decrease initially up to a certain bluntness ratio, then increase, followed by a gradual decrease for large values of bluntness ratios. This decrease or increase inside-force levels with nose blunting is associated with a corresponding increase or decrease, respectively, in the onset of vortex asymmetry.Whereas the increase in side-force level beyond the first minimum is qualitatively similar to that observed in earlier studies, the present data definitely indicate that there is a progressive decrease inside-force levels to relatively low values for large bluntness ratios,which could form an important design input. The bluntness ratio corresponding to the occurrence of the first minimum in (maximum) side force depends on the cone angle and is nearly independent of Reynolds number.

Fabrication of Superhydrophobic Nanocomposite Coatings Using Polytetrafluoroethylene and Silica Nanoparticles

Abstract: Superhydrophobic nanocomposite coatings were fabricated by incorporating hydrophobically modified silica (HMS) nanoparticles in polytetrafluoroethylene (PTFE) emulsion. Hydrophobicity of the coating was dependent on the concentration of HMS. Coatings containing optimum amounts of PTFE and HMS exhibited superhydrophobic property with high water contact angle (WCA) of 165∘ and low sliding angle <2∘. Scanning electron microscopic (SEM) studies have shown a binary surface topography composed of microbumps and nanoscale granules. The synergistic effect of the micro-nano-binary structure and low surface energy of PTFE was responsible for the superhydrophobicity of the coating. The method is simple and cost-effective and can be used for preparing self-cleaning superhydrophobic coatings on large areas of different kinds of substrates like glass, metal, and composites.

Synthesis of TiN Reinforced Aluminium Metal Matrix Composites Through Microwave Sintering

Abstract: Al-TiN (10, 20, 30 wt.%) composites were fabricated by using microwave radiation. Al and TiN powders were selected as starting materials, mixed in a ball mill for ~10 min and sintered for various times. Results indicate that an optimum microwave sintering time of 2 min was essential and responsible for the improved densification and mechanical properties. The presence of TiN particles at grain boundaries plays a significant role in improving the densification and hardness values. Dry sliding wear results show the improved wear resistance of the composite (Al-TiN) due to the presence of TiN particles and the wear results are superior to the Al-TiN samples made by hot pressing technique.

Tracking filter and multi-sensor data fusion

Abstract: In this paper factorization filtering, fusion filtering strategy and related algorithms are presented. Some results of implementation and validation using realistic data are given.