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.

Active vibration control of smart plates with partially debonded multilayered PZT actuators

Abstract: The influence of actuator damage on the performance of closed loop vibration control is numerically evaluated. Debonding is considered a damage mode and finite element procedures are subsequently developed to introduce its effect on system matrices, namely elastic and electro-elastic stiffness. A simple modelling scheme for multiple debonding is proposed, which can also idealize multiple delamination in the host laminate. Debonding in actuators in general has reduced their load carrying appreciably as well as vibration control characteristics. Therefore, incorporating such a damage mode in the control design as an uncertainty parameter would help to realize a damage-tolerant active vibration control system. It is interesting to note that debonding in actuators has influenced both active damping and active stiffening effects.

Tailored periodic Si nanopillar based architectures as highly sensitive universal SERS biosensing platform

Abstract: We report a skeleton key platform for surface enhanced Raman spectroscopy (SERS) based biosensor, utilizing ordered arrays of Si nanopillars (SiNPLs) with plasmonic silver nanoparticles (AgNPs). The optimized SiNPLs based SERS (SiNPLs-SERS) sensor exhibited high enhancement factor (EF) of 2.4 × 108 for thiophenol with sensitivity down to 10−13 M of R6G molecules. The ordered array of SiNPLs stabilizes the distribution of AgNPs along with the light trapping properties, which resulted in high EF and excellent reproducibility. The uniformity in the arrangement of AgNPs makes a single SiNPLs-SERS substrate to work for all types of biomolecules such as positively and negatively charged proteins, hydrophobic proteins, cells and dyes, etc. The experiments conducted on differently charged proteins, amyloid beta (the protein responsible for alzheimers), E. coli cells, healthy and malaria infected RBCs provide a proof of concept for employing universal SiNPLs-SERS substrate for trace biomolecule detection. The FDTD simulations substantiate the superior performance of the sensor achieved by the tremendous increase in the hotspot distribution compared to the bare Si sensor.

Compression behavior of VC0.85 up to 53 GPa

Abstract: Samples of VC0.85 sandwiched between aluminum disks were compressed in a diamond anvil cell and X-ray diffraction patterns recorded at high pressures up to 53 GPa using synchrotron radiation. The presence of aluminum in the cell rendered the sample pressure nearly hydrostatic and also served as the pressure standard. No phase transformation was observed up to the highest pressure. The measured unit cell volume versus pressure data gave 258 ± 11 GPa and 4.5 ± 0.6 for the bulk modulus and the pressure derivative, respectively.