Institution
National Aerospace Laboratories
Facility•Bengaluru, India•
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.
Topics: Coating, Corrosion, Mach number, Sputter deposition, Aerodynamics
Papers published on a yearly basis
Papers
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TL;DR: In this article, the residual effects of thermal ageing at various temperatures on fibres of the aliphatic polyamide Nylon 6,6 have been studied and a direct correlation between the tensile strength and the angular separation of the equatorial reflections has been observed.
Abstract: The residual effects of thermal ageing at various temperatures on fibres of the aliphatic polyamide Nylon 6,6 have been studied. Both crystal and macro structural characteristics manifest the residual effects. The former category includes changes in intensity, 2θ values and half width. The macro changes include introduction of surface damages in the form of holes, material deposits etc. The fibre also undergoes reduction in weight. The structural changes suggest deterioration in the initial tensile characteristics which has been verified experimentally. A direct correlation between the tensile strength and the angular separation of the equatorial reflections has also been observed.
30 citations
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TL;DR: In this article, the authors discussed the nature of shock unsteadiness in an overexpanded thrust optimized parabolic nozzle, prevalent in various flow separation modes experienced during start up and shutdown.
Abstract: This paper discusses the nature of shock unsteadiness, in an overexpanded thrust optimized parabolic nozzle, prevalent in various flow separation modes experienced during start up \({(\delta P_{0} /\delta t > 0)}\) and shut down \({(\delta P_{0}/\delta t < 0)}\) sequences. The results are based on simultaneously acquired data from real-time wall pressure measurements using Kulite pressure transducers, high-speed schlieren (2 kHz) of the exhaust flow-field and from strain-gauges installed on the nozzle bending tube. Shock unsteadiness in the separation region is seen to increase significantly just before the onset of each flow transition, even during steady nozzle operation. The intensity of this measure (rms level) is seen to be strongly influenced by relative locations of normal and overexpansion shock, the decrease in radial size of re-circulation zone in the back-flow region, and finally, the local nozzle wall contour. During restricted shock separation, the pressure fluctuations in separation region exhibit periodic characteristics rather than the usually observed characteristics of intermittent separation. The possible physical mechanisms responsible for the generation of flow unsteadiness in various separation modes are discussed. The results are from an experimental study conducted in P6.2 cold-gas subscale test facility using a thrust optimized parabolic nozzle of area-ratio 30.
30 citations
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TL;DR: In this paper, active stiffening and active compensation analyses are carried out to present the influence of active stiffness on the dynamic behaviour of piezo-hygro-thermo-elastic laminates.
30 citations
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TL;DR: In this paper, single-layer TiN/a-C nanocomposite coatings were prepared on silicon (111) and M3 tool steel substrates by rotating the substrate back and forth between the titanium and the graphite targets.
Abstract: Single layer TiN coatings were prepared on silicon (111) substrates using a multi-target reactive DC magnetron sputtering process at various nitrogen flow rates and substrate biases. TiN coatings prepared at a nitrogen flow rate of 0.6 sccm, a power density of 5.4 W/cm2 and a substrate bias of −275 V, showed a nanoindentation hardness of 3300 kg/mm2, whereas amorphous carbon (a-C) coatings prepared under similar deposition conditions exhibited a hardness of 800 kg/mm2. Subsequently, nanocomposite coatings of TiN/a-C were prepared on silicon (111) and M3 tool steel substrates by rotating the substrate back and forth between the titanium and the graphite targets. The nanocomposite coatings were prepared at various carbon concentrations. Structural characterization of the coatings was done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The compositions of the coatings were determined using energy dispersive X-ray analysis (EDAX). The nanocomposite coatings exhibited a broad (111) reflection of cubic TiN phase in XRD data. Nanoindentation data showed that about 1.5-μm-thick TiN/a-C nanocomposite coatings exhibited a maximum hardness of 4800 kg/mm2 at a carbon concentration of approximately 17 at.%. The TEM micrographs showed that TiN nanocrystals were embedded in a-C matrix and the average crystallite size was 78 A. The selected area electron diffraction of the nanocomposite coatings showed the presence of both nanocrystalline (TiN) and amorphous (a-C) phases. This was confirmed by high-resolution TEM studies.
30 citations
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TL;DR: In this article, the effects of heat treatment on structure, morphology and elemental states of electrodeposited Co-W alloy coatings obtained from gluconate bath were characterized by XRD, FESEM and XPS.
30 citations
Authors
Showing all 1850 results
Name | H-index | Papers | Citations |
---|---|---|---|
Harish C. Barshilia | 46 | 236 | 6825 |
K.S. Rajam | 42 | 83 | 4765 |
Kozo Fujii | 39 | 411 | 5845 |
Parthasarathi Bera | 39 | 136 | 5329 |
R.P.S. Chakradhar | 36 | 166 | 4423 |
T. N. Guru Row | 36 | 309 | 5186 |
Takashi Ishikawa | 36 | 154 | 5019 |
Henk A. P. Blom | 34 | 168 | 5992 |
S. Ranganathan | 33 | 211 | 5660 |
S.T. Aruna | 33 | 101 | 4954 |
Arun M. Umarji | 33 | 207 | 3582 |
Vinod K. Gaur | 33 | 92 | 4003 |
Keisuke Asai | 31 | 350 | 3914 |
K. J. Vinoy | 30 | 240 | 3423 |
Gangan Prathap | 30 | 241 | 3466 |