K. Venkataramaniah

Sri Sathya Sai Institute of Higher Learning, Anantapuramu, Andhra Pradesh, India

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Publications (69)65.24 Total impact

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    ABSTRACT: The aqueous based reflux method useful for the green synthesis of nanostructures is described in detail. In this method, the parameters: the order of addition of precursors, the time of the reflux and the cooling rate should be optimized in order to obtain the desired phase and morphology of the nanostructures. The application of this method is discussed with reference to the synthesis of CZTS nanoparticles which have great potential as an absorber material in the photovoltaic devices. The highlights of this method are:
    Preview · Article · Dec 2015 · MethodsX
  • S. Deepa · Dwaraka Rani Rao · K. Venkataramaniah
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    ABSTRACT: The decay of 153Sm was studied with a HPGe detector and a Si(Li) detector based electron transporter. Forty four gamma transitions belonging to sixteen excited levels in the daughter nucleus 153Eu were analyzed for their energies, emission intensities, conversion electron intensities and conversion coefficients. These values have resulted in the determination of precise beta emission intensities to the levels in 153Eu and in the construction of an internally consistent decay scheme. The present study will add to the decay data available on this radionuclide for reliable dose estimations for medical applications.
    No preview · Article · Oct 2015 · Radiation Physics and Chemistry
  • Penamati Suresh · Kamisetti Venkataramaniah · Thayananthan Thayaparan
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    ABSTRACT: In many applications, it may be desired to decompose a non-stationary signal into its individual components. If spectral components of the non-stationary signal do not overlap in the frequency domain then Fourier transform can be used to decompose the non-stationary signal. Fourier transform fails to decompose the non-stationary signal if its spectral components overlap in the frequency domain. In this study, the authors propose Fourier-Bessel transform and the time-frequency analysis in conjunction with the fractional Fourier transform (FB-TF) method for the separation of multi-component non-stationary signal whose components overlap in both time and/or frequency domains. The efficiency of the proposed method is compared with one of the traditional decomposition methods like EMD. The proposed approach is applied to both simulated and experimental radar data. Results demonstrate the effectiveness of the proposed method for non-stationary signal separation and for detecting manoeuvring target in heavy sea-clutter environments. The improvement factor and clutter attenuation are calculated and used to compare the performance of the EMD and the FB-TF methods in suppressing the sea-clutter and enhancing target detection. The proposed method can be used as a potential tool for detecting and enhancing the low observable manoeuvring air targets in the sea-clutter environment.
    No preview · Article · Jun 2015 · IET Radar Sonar ? Navigation
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    ABSTRACT: The chalcopyrite semiconductors belonging to the I2-II-IV-VI4 class are emerging as promising absorber materials for photovoltaic applications. Among them, Cu2ZnSnS4 (CZTS) has been gaining importance due to its high absorption coefficient and optimum band-gap. To make CZTS an economically viable alternative, in this study, the CZTS powder has been synthesized via a low-cost, environment-friendly reflux method. In the current method, the salts of the respective metals were taken as initial precursors, and thiourea was used as a precursor for sulfur. The stoichiometric amounts of the precursors were taken in distilled water and the solution was refluxed for 8 h. The products were filtered and washed with distilled water and ethanol consecutively. Phase identification was done using powder X-ray diffraction (given by the reference pattern JCPDS card no. #00-026-0575) and Raman spectroscopy analysis (corresponding Raman shifts for CZTS: 288 and 338 cm-1). The band gap of the compound was calculated from the UV-visible spectroscopy and found to be 1.4 eV.
    No preview · Article · Jan 2015
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    ABSTRACT: A well-known limitation in the fabrication of metal-graphene composite has been the use of surfactants that strongly adsorb on the surface and reduce the performance of the catalyst. We demonstrate here a novel one-pot synthesis of gold nanoparticles by laser ablation of gold strip and in-situ decoration on graphene substrate. Not only the impregnation of nanoparticles was linker free, but also the synthesis by itself was surfactant-free. The composite materials were well characterized morphologically and functionally using electron microscopy, X-ray and electron diffraction, Raman spectroscopy, Zeta potential, electrochemical measurements and UV-Visible spectroscopic techniques. This linker-free gold-graphene based composite has been employed for catalytic applications pertaining to electrooxidation. We have explored the use of this composite as a binder-free electrode in electrocatalytic oxidation of methanol and ethanol in alkaline medium. Additionally, the onset potential for ethanol oxidation was found to be more negative, −100 mV, an indication of its promising application in direct ethanol fuel cells.
    Full-text · Article · Aug 2014 · Electroanalysis
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    ABSTRACT: In recent times ZnO nanomaterials have been studied extensively because of its wide direct band gap of 3.37eV at 300K and large exciton binding energy of 60 meV. ZnO nanomaterials have been doped with various elements, e.g., Ni, Fe, Mn, Co, V etc. for different applications. In this work, ZnO nanoparticles have been synthesized by hydrothermal route with 0% and 0.6 at.% Mn doping. The samples have been characterized by XRD, FESEM and UV-Vis absorption spectroscopy. Open-aperture z-scan technique was employed to study the nonlinear optical absorption behavior of the synthesized samples using a second harmonic (532 nm) of Nd: YAG laser with 15 ns pulse width. The z-scan data was numerically fitted using the Python code to decipher the mechanism of optical nonlinearity in ZnO and Mn doped ZnO nanoparticles. We found that the nonlinear transmittance curve fits to a three-photon absorption process and the nonlinear absorption is enhanced in the case of 0.6 at % Mn doped ZnO nanoparticles compared to undoped ZnO. The three-photon absorption coefficient γ (3) was found to be 0.6 x 10 -23 m 3 /W 2 in case of ZnO and 1.0 x 10 -23 m 3 /W 2 in case of 0.6 at % Mn doped ZnO nanoparticles.
    Full-text · Article · Jun 2014
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    Full-text · Article · Jun 2014
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    Full-text · Article · Jun 2014
  • Padmashri Suresh · T. Thayaparan · T. Obulesu · K. Venkataramaniah
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    ABSTRACT: In this paper, we report the efficiency of the Fourier-Bessel transform (FBT) and time-frequency (TF)-based method in conjunction with the fractional Fourier transform (FrFT), for extracting micro-Doppler (m-D) radar signatures from the rotating targets. This approach comprises mainly of two processes, with the first being the decomposition of the radar return, in order to extract m-D features, and the second being the TF analysis to estimate motion parameters of the target. In order to extract m-D features from the radar signal returns, the time domain radar signal is decomposed into stationary and nonstationary components using the FBT in conjunction with the FrFT. The components are then reconstructed by applying the inverse Fourier-Bessel transform (IFBT). After the extraction of the m-D features from the target's original radar return, TF analysis is used to estimate the target's motion parameters. This proposed method is also an effective tool for detecting maneuvering air targets in strong sea clutter and is also applied to both simulated data and real-world experimental data.
    No preview · Article · May 2014 · IEEE Transactions on Geoscience and Remote Sensing
  • Molli Muralikrishna · B. Ravikanth · P. Sowmendran · V. Sai Muthukumar · Kamisetti Venkataramaniah
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    ABSTRACT: In this work, we report for the first time, the nonlinear optical absorption properties of antimony selenide (Sb2Se3) nanoparticles synthesized through solvothermal route. X-ray diffraction results revealed the crystalline nature of the nanoparticles. Electron microscopy studies revealed that the nanoparticles are in the range of 10 - 40 nm. Elemental analysis was performed using EDAX. By employing open aperture z-scan technique, we have evaluated the effective two-photon absorption coefficient of Sb2Se3 nanoparticles to be 5e-10 m/W at 532 nm. These nanoparticles exhibit strong intensity dependent nonlinear optical absorption and hence could be considered to have optical power limiting applications in the visible range.
    No preview · Conference Paper · May 2014
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    A. Jagadeesh · T. Mimani Rattan · M. Muralikrishna · K. Venkataramaniah
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    ABSTRACT: A single phase of orthorhombic nano-vanadium pentoxide (V2O5) is produced using a one pot synthesis method of solution combustion process. The yellow-orange colored powder of V2O5 is obtained instantaneously by this method and has elliptical to spherical like morphology of its platelets. A majority of these particles are in the size range of less than 200 nm. As revealed by SAED this simple method of synthesis yields a highly crystalline product with monocrystalline and polycrystalline particles of V2O5 existing in the same matrix. The product shows a negative temperature coefficient of resistance (TCR) value of -3.2% degrees C-1 and a low hysteresis effect with temperature width of 5 degrees C in response to temperature variations. Such characteristics demonstrate that preparation of V2O5 by this facile method renders it a promising candidate for bolometric applications.
    Full-text · Article · Apr 2014 · Materials Letters
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    Full-text · Conference Paper · Dec 2013
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    K Vijay Sai · R Gowrishankar · S Deepa · Dwarakarani Rao · K Venkataramaniah

    Full-text · Conference Paper · Dec 2013
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    ABSTRACT: Surface plasmon coupled emission (SPCE) is a novel analytical technique in which the isotropic emission of a fluorophore is combined with the surface plasma resonance of a Ag (or Au) thin film to yield highly directional emission from the so-called plasmaphore, and thus greatly increased sensitivity. Here we report a 40-fold amplification of rhodamine b (RhB) fluorophore when graphene is used as the spacer layer in a conventional Ag-based SPCE setup. In addition to protecting the Ag thin film from oxidation, the highly impermeable graphene facilitated ∏-∏ stacking interactions with the RhB molecules and resulted in an efficient radiated emission from the plasmaphore. In addition, we found that the plasmaphore emission was more sensitively on the in-plane crystallinity (measured by coherence length La) of the graphene spacer layer than its thickness. This study describes the unique features of graphene as a spacer layer for SPCE-based analytical platforms and its potential applications in chem-bio sensing and detection.
    No preview · Article · Jul 2013 · The Journal of Physical Chemistry C
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    No preview · Dataset · Apr 2013
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    ABSTRACT: A well known disadvantage in fabrication of metal-graphene composite is the use of surfactants that strongly adsorb on the surface and reduce the performance of the catalyst. Here, we demonstrate a novel one pot synthesis of gold nanoparticles (AuNPs) by laser ablation of gold strip and simultaneous decoration of these on functionalized graphene derivatives. Not only the impregnation of AuNPs was linker free, but also the synthesis by itself was surfactant free. This resulted in \textit{in-situ} decoration of pristine AuNPs on functionalized graphene derivatives. These materials were well characterized and tested for catalytic applications pertaining to dye reduction and electrooxidation. The catalytic reduction rates are 1.4 x 102 and 9.4x102 times faster for Rhodamine B and Methylene Blue dyes respectively, compared to earlier reports. The enhanced rate involves synergistic interplay of electronic relay between AuNPs and the dye, also charge transfer between the graphene system and dye. In addition, the onset potential for ethanol oxidation was found to be more negative ∼ 100 mV, an indication of its promising application in direct ethanol fuel cells.
    No preview · Article · Mar 2013
  • B. Pfeiffer · K. Venkataramaniah · U. Czok · C. Scheidenberger
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    ABSTRACT: Atomic mass reflects the total binding energy of all nucleons in an atomic nucleus. Compilations and evaluations of atomic masses and derived quantities, such as neutron or proton separation energies, are indispensable tools for research and applications. In the last decade, the field has evolved rapidly after the advent of new production and measuring techniques for stable and unstable nuclei resulting in substantial ameliorations concerning the body of data and their precision. Here, we present a compilation of atomic masses comprising the data from the evaluation of 2003 as well as the results of new measurements performed. The relevant literature in refereed journals and reports as far as available, was scanned for the period beginning 2003 up to and including April 2012. Overall, 5750 new data points have been collected. Recommended values for the relative atomic masses have been derived and a comparison with the 2003 Atomic Mass Evaluation has been performed. This work has been carried out in collaboration with and as a contribution to the European Nuclear Structure and Decay Data Network of Evaluations.
    No preview · Article · Jan 2013 · Atomic Data and Nuclear Data Tables
  • P. Suresh · K. Venkataramaniah · T. Thayaparan
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    ABSTRACT: This paper presents new approach for detecting a maneuvering target from strong sea clutter environment, which is based on a combination of Fourier Bessel transform, fractional Fourier transform and time-frequency based method. In order to detect a maneuvering target from radar signal returns, the time domain radar signal is decomposed into stationary and non-stationary components using Fourier Bessel transform. The components are then reconstructed by applying both the fractional Fourier transform and the inverse Fourier Bessel transform. This proposed approach is applied to both simulated data and measured data. Results demonstrate the effectiveness of the proposed method for detecting maneuvering target in a heavy sea clutter.
    No preview · Conference Paper · Jan 2013
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    S. Deepa · K. Vijay Sai · R. Gowrishankar · K. Venkataramaniah
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    ABSTRACT: Gamma emissions in the decay of 160.44 day isomer 177mLu were analyzed with a 60cc, coaxial HPGe detector. The energies and intensities of 50 gamma transitions—40 of which belong to the daughter 177Hf, that was excited by beta decay of the isomer, and 10 to the isomeric transition in 177Lu were precisely determined. These precise values have resulted in an internally consistent decay scheme for 177mLu. These gamma intensity and gamma emission probability measurements will help in making the long lived 177mLu available as a calibration standard for HPGe detectors and also for other applications.
    Full-text · Article · Mar 2012 · Radiation Physics and Chemistry
  • P. C.sood · M.sainath · K.venkataramaniah
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    ABSTRACT: The low-energy two-quasiparticle bandhead energies for the odd-odd Z=101 nucleus 250Md are evaluated using a zero range residual neutron-proton interaction. The 250Md ground state is seen to have the spin-parity Iπ=0- corresponding to the singlet band from the configuration {p : 7/2[514]⊗n:7/2[624]} in violation of the Gallagher-Moszkowski (GM) coupling rule. The situation here is shown to be almost identical to that for the rare-earth nucleus 166Ho, which is the only well-established exception to the GM rule known so far. Analysis of the expected low energy spectrum, including the rotational levels, for 250Md reveals the occurrence of an as-yet-unobserved long-lived high-spin Iπ = 7- isomeric state around (80±30) keV with dominant ε and α decay modes.
    No preview · Article · Jan 2012 · International Journal of Modern Physics E

Publication Stats

241 Citations
65.24 Total Impact Points

Institutions

  • 1997-2015
    • Sri Sathya Sai Institute of Higher Learning
      • Department of Physics
      Anantapuramu, Andhra Pradesh, India
  • 2007-2010
    • Sri Sai University
      Patampar, Himachal Pradesh, India
  • 2008
    • Sri Sathya Sai Institute of Higher Medical Science, Prasanthi Nilayam
      Koyambattūr, Tamil Nadu, India