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.

The key role of thread and needle selection towards ‘through-thickness reinforcement’ in tufted carbon fiber-epoxy laminates

Abstract: Tufting of dry preforms is one of the means of accomplishing through-thickness reinforcement (TTR) in a liquid composite molding process. Herein, once a preform is laid up, an automated robotic tufting setup is used to introduce the TTR. The selection of thread and needle for tufting process go hand-in-hand as tufting operation involves the act of penetrating preform by the needle as well as the trauma thread has to endure during this act. This paper explores the methodology of thread and needle selection through studies at different levels right from tufting of preforms to testing of tufted laminates. Glass, carbon and Kevlar threads in combination with a tufting needle and two different sewing needles are explored in this study. The effect of tufting speed on the quality of tuft is analyzed in terms of damage of fabric yarn, thread, and needle breakage. Layer-wise analysis of damage due to needle penetration in fabric yarns is carried out. Key mechanical properties of tufted composite samples are evaluated to determine the effect of tufting on the in-plane and out-of-plane properties.

Carbon plasma immersion ion implantation and DLC deposition on Ni-Ti alloy

Abstract: Carbon plasma immersion ion implantation (PIII-C) has been performed on Ni−Ti alloy surface using methane as a precursor gas at low temperature and it has been followed by deposition of diamond-like carbon (DLC) coating. Untreated and coated alloys are characterized with field emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical impedance spectroscopy, and corrosion testing in Hanks’ solution which is simulated body fluid show that corrosion resistance has been enhanced in PIII-C + DLC-coated alloy compared to untreated alloy. The in vitro studies of untreated and PIII-C + DLC-coated alloys have been evaluated using osteoblast-like cells (MG-63). Cellular behavior in terms of cell morphology along with the viability and cell spreading has been evaluated using scanning electron microscopy and in vitro cell culture assay, respectively. In comparison to Ni–Ti alloy, the coated alloy exhibits better cell viability indicating their biocompatibility

Numerical and Theoretical Considerations for the Design of the AVT-183 Diamond-Wing Experimental Investigations

Abstract: A diamond-wing configuration has been developed to isolate and study blunt-leading edge vortex separation with both computations and experiments. The wing has been designed so that the results are relevant to a more complex Uninhabited Combat Air Vehicle concept known as SACCON. The numerical and theoretical development process for this diamond wing is presented, including a view toward planned wind tunnel experiments. This work was conducted under the NATO Science and Technology Organization, Applied Vehicle Technology panel. All information is in the public domain.

Fabrication of a bi-luminophore temperature sensitive coating by embedding europium thenoyltrifluoroacetonate (EuTTA) and perylene in polystyrene.

Abstract: A new bi-luminophore system for optical sensing of temperature is described. The coating was fabricated by embedding europium thenoyltrifluoroacetonate (EuTTA) and perylene in polystyrene (PS) matrix. The luminescence emission of EuTTA was sensitive to temperature whereas perylene emission was temperature-insensitive and was used as a reference. Both luminophores were excited in the UV region of about 330 to 380 nm. The fluorescence emission of perylene and EuTTA occured at 474 nm and 615 nm respectively. The temperature sensitivities of both luminophores were influenced by (i) the type of polymer, and (ii) the concentration of luminophore in the matrix. Combining EuTTA and perylene in polystyrene matrix, a new bi-luminophore temperature sensing coating was developed. The temperature sensitivity of this coating was −1.80%/°C in the temperature range of 5 °C to 50 °C. The emission characteristics of this temperature sensitive coating displayed a fully reversible response to temperature.