K. Venkataramaniah

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

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Publications (50)50.61 Total impact

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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.
    Electroanalysis 07/2014; · 2.82 Impact Factor
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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.
    International Journal of Nanotechnology and Application (IJNA). 06/2014; 4(3):39-44.
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    International Journal of Nanotechnology and Application. 06/2014; 4(3):21-28.
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    International Journal of Nanotechnology and Application. 06/2014; 4(3):39-44.
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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.
    58th DAE Solid State Physics Symposium; 05/2014
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    International Symposium on Nuclear Physics, BARC, Mumbai, India; 12/2013
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    International Symposium on Nuclear Physics, BARC, Mumbai, India; 12/2013
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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.
    The Journal of Physical Chemistry C 07/2013; · 4.84 Impact Factor
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    Dataset: scholar
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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.
    Bulletin of the American Physical Society. 03/2013;
  • 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.
    Atomic Data and Nuclear Data Tables 01/2013; · 1.00 Impact Factor
  • 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.
    Radiation Physics and Chemistry 03/2012; · 1.38 Impact Factor
  • 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.
    International Journal of Modern Physics E 01/2012; 09(04). · 0.63 Impact Factor
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    ABSTRACT: In people with diabetes, lack of insulin or its ineffectiveness completely disturbs the metabolic process and consequently glucose builds up in the blood stream. The occurrence of diabetes mellitus is connected with the changes in the micronutrient status of the body as these nutrients play a specific role in production and action of insulin. A region-specific (Anantapur District of Andhra Pradesh, India) study on trace element concentrations in diabetic blood serum and comparison with trace levels in normal blood has been carried out using PIXE to correlate the deficiency or excess of trace element levels in diabetic patients. Deficiency of Fe, Mn, Cr and Zn and higher levels of S and K have been found in people suffering from diabetes in this region.
    Research & Reviews: A Journal of Medicine. 12/2011; 1(3):1.
  • Muralikrishna Molli, K. Venkataramaniah, S. R. Valluri
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    ABSTRACT: In this work, we determine the conditions for the extremum of the figure of merit,  2, in a degenerate semiconductor for thermoelectric (TE) applications. We study the variation of the function  2 with respect to the reduced chemical potential μ* using relations involving polylogarithms of both integral and nonintegral orders. We present the relevant equations for the thermopower, thermal, and electrical conductivities that result in optimizing  2 and obtaining the extremum equations. We discuss the different cases that arise for various values of r, which depends on the type of carrier scattering mechanism present in the semiconductor. We also present the important extremum conditions for  2 obtained by extremizing the TE power factor and the thermal conductivity separately. In this case, simple functional equations, which lead to solutions in terms of the Lambert W function, result. We also present some solutions for the zeros of the polylogarithms. Our analysis allows for the possibility of considering the reduced chemical potential and the index r of the polylogarithm as complex variables.
    Canadian Journal of Physics 11/2011; 89(11):1171-1178. · 0.90 Impact Factor
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    ABSTRACT: Complete precision electron and gamma spectroscopy measurements were undertaken for the 6.647 day decay of (177)Lu. Precision measurements of the K, L, and M internal conversion coefficients (ICCs) were made using a high transmission Mini Orange Electron Spectrometer coupled to a Si(Li) detector. We also report energies and intensities of the 6 gamma rays measured with a large volume 60 cc HPGe detector and 9 X-rays with better precision. The energies and intensities of the beta transitions from (177)Lu leading to the levels in the daughter (177)Hf were calculated by transition intensity balance at the levels.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 02/2011; 69(6):869-74. · 1.09 Impact Factor
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    ABSTRACT: Intensity-dependent nonlinear optical transmission studies of cadmium sulfide (CdS) nanowires (∼ 50–100 nm diameter) suspended in dimethylformamide have been carried out in the visible region using the Z-scan technique with 7 ns pulses from the second harmonic of an Nd:YAG laser. The optical limiting threshold of CdS nanowires suspension was determined to be 1.3 J cm− 2, with normalized transmittance of 0.47, which is relatively lower when compared with those of many popular metal nanowire suspensions reported in the literature. Based on an effective three-photon absorption model, nonlinear absorption and nonlinear scattering were identified as the dominant processes for the measured reduced transmittance.
    Optics Communications 01/2010; 283(20):4104-4107. · 1.44 Impact Factor
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    DAE Symposium on Nuclear Physics; 01/2010
  • DAE Symposium on Nuclear Physics; 01/2010
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    ABSTRACT: Service Providers are constantly searching for means to reduce costs, generate new revenue streams and thus increase their competitive advantage. The migration to a Colorless and Directionless mesh architecture will enable the Service Providers to realise scalable, flexible and dynamically reconfigurable optical networks. But commodification and standardization of the underlying technologies has made it very difficult to differentiate their service offerings especially in terms of price and performance. Hence, leveraging the intelligence of efficient routing algorithms, Service Providers can notably reduce the total cost of ownership of the network. This paper presents a rationalized routing algorithm for a Colorless and Directionless mesh core optical network, which enables a significant CAPEX reduction by decreasing the number of active degrees of a node.
    Optical Switching and Networking. 01/2010; 7:141-152.

Publication Stats

72 Citations
50.61 Total Impact Points

Institutions

  • 1997–2014
    • Sri Sathya Sai Institute of Higher Learning
      • Department of Physics
      Anantapuramu, Andhra Pradesh, India
  • 2007–2010
    • Sri Sai University
      Patampar, Himachal Pradesh, India
  • 1999
    • Banaras Hindu University
      • Department of Physics
      Benares, Uttar Pradesh, India