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Suche nach „[A.] [Sharma]“ hat 2 Publikationen gefunden
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    NachhaltigAngewandte Naturwissenschaften und Wirtschaftsingenieurwesen

    Zeitschriftenartikel

    S. Sharma, Himani Jain, M. Kulkarni, G. Patil, B. Bhattacharya, A. Sharma

    PZT–PDMS composite for active damping of vibrations

    Composites Science and Technology, vol. 77, no. 22 March, pp. 42-51

    2013

    DOI: 10.1016/j.compscitech.2013.01.004

    Abstract anzeigen

    A Lead Zirconate-Titanate (PZT)/poly-dimethylsiloxane (PDMS) based flexible composite is synthesized and investigated for its potential in significantly enhancing the vibration damping capability along with its tunable properties. Rheologically and functionally different PZT/PDMS composites are prepared by dispersing different volume fractions of piezoelectric soft/hard PZT and Fe particles in a cross-linked PDMS matrix. It is observed that passive damping increases with increase in the soft PZT volume fraction from 0 to 0.32. This effect becomes more prominent after poling the composite at optimum conditions. The loss factor depends on the viscoelastic properties of the PDMS, homo and hetero-particle connectivity in the composite, and polarization and localization of the PZT particles in composite. Rheological analysis of the composite shows that the material loss factor (tan δ) increases linearly from ∼0.3 to 0.75 along with a broadening of the peak when the PZT volume fraction is increased from 0 to 0.32. Maximum structural damping (η) is obtained at 0.32 (V/V) of the soft-PZT as measured by the Oberst beam technique. This effect becomes more pronounced after a poling treatment. The X-ray diffraction results indicate that the dispersed PZT particles in PDMS matrix have the lattice parameters of a = 5.84 Å, c = 14.41 Å and (0 0 1) orientation. Further, after poling treatment, the dielectric constant and the piezoelectric coefficient (d33) for soft (submicron) PZT filler particles in PDMS matrix tend to be higher than those for hard PZT. The soft PZT/PDMS composite shows better performance as a damper than the hard, PZT composite.

    NachhaltigAngewandte Naturwissenschaften und Wirtschaftsingenieurwesen

    Zeitschriftenartikel

    P. Barhai, R. Sharma, A. Yadav, A. Singh, Himani Jain, V. Buck

    Surface modification of PMMA with DLC using RF-PECVD

    ECS Transactions (The Electrochemical Society), vol. 25 (216th ECS Meeting, Vienna, Austria), no. 8, pp. 829-836

    2009

    DOI: 10.1149/1.3207673

    Abstract anzeigen

    DLC films are deposited on PMMA substrates using Radio Frequency Plasma Enhanced Chemical Vapour Deposition (RF-PECVD) technique with the variation of RF power at a constant pressure of 5 × 10-2 mbar. Acetylene diluted with argon is used as a precursor for the deposition of DLC films. No external heating is provided during deposition. Deposited films are characterized using Raman spectroscopy, FTIR spectroscopy, Optical contact angle (OCA) technique and AFM. Raman spectra shows a G peak near 1550 cm-1 and a D peak near 1320 cm-1. FTIR spectra shows a peak near 2900 cm-1 corresponding to C-H stretching modes and peaks below 2000 cm-1 corresponding to C-C modes and C-H bending modes. Surface morphology of the films has been studied with AFM and the result shows the formation of uniform films. Optical contact angle (OCA) shows that DLC coated PMMA is more hydrophobic compared to uncoated surface.