K. Venkataramaniah

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

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Publications (42)46.29 Total impact

  • Source
    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; · 4.81 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
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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.
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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
  • 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.
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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
  • DAE Symposium on Nuclear Physics; 01/2010
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    ABSTRACT: Metallic nano structures exhibit interesting optical properties due to the coupling of surface plasmon resonances with the electromagnetic fields. Metal nano particles exhibit dramatic field enhancement in the vicinity of the nano particle which can be further increased by near field coupling between closely spaced particles. In this paper, we study a system made of 3 nano cylinders placed at the vertices of an equilateral triangle. Near field optical responses of the system of silver nano cylinders interacting with the incident plane wave was simulated by finite difference time domain (FDTD) method in the visible light region. We attempt to study influences of the radius of the nano cylinders and inter-particle distances on the resonances.
    International Journal of Physical Sciences. 05/2009; 4:250-252.
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    ABSTRACT: Microwave-assisted, solid-state grafting of multiwalled carbon nanotubes is presented for the synthesis of a thermal polyurethane composite. This one-step method reduced the reaction time to the order of minutes and allowed the polyurethane to be directly attached to the nanotubes, thus forming a highly solvent-dispersible composite. The composite showed excellent optical limiting characteristics at 532 as well as 1064 nm, with a threshold of 0.10 J cm−2 at 532 nm, and a higher value (1.0 J cm−2) at the latter wavelength.
    Journal of Materials Chemistry 04/2009; 19(10.1039/B906764G):6568-6572. · 5.97 Impact Factor
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    ABSTRACT: In core/metro optical networks there are multi-degree nodes providing N path interconnections and alternate paths for protection. This paper presents the optimum implementation of a colorless and directionless add/drop switching feature in a mesh network, using the WSS based ROADM. The idea of scaling, viewed as an increase in route degree and number of wavelengths handled in each direction is then addressed. Subsequently, we suggest the best ways in which specific advantages like dynamically optimizing light paths by optical bridge-and-roll, avoiding O-E-O operations and blocking specific wavelengths can be leveraged. Finally, practical implementation issues like power loss, OSNR and cost considerations are discussed.
    Communication Systems and Networks and Workshops, 2009. COMSNETS 2009. First International; 02/2009
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    ABSTRACT: The Aharonov-Bohm interferometer (ABI) in a two-terminal configuration is a reliable tool to study electron transport in nanoscopic systems. Characterization of the ABI using the Griffith boundary conditions at the junctions of the leads and the ring reported earlier by Kumar and Sahoo (Inter. Jour. Mod. Phys. B 19, 3483 (2005)) are reanalyzed using improved boundary conditions recently proposed by Voo and Chen (Phys Rev B 73, 035307 (2006)). Transmittance (T) of electron as the electron momentum k is varied shows sharp localized peaks. The minimum of T as k is varied over a large range shows progressive increase with k and eventually saturates. Modification of T near the values of k corresponding to the resonances of the ring (without the leads) is not significant. However, noticeable changes do appear off the resonance positions. For the ABI with a spin half impurity-the problem investigated earlier by Joshi Sahoo and Jayannavar (Phys. Rev. B 64, 075320-1 (2001))-we find qualitative differences between large and small k behavior similar to the perfect ABI case. However, in the presence of magnetic flux, the interferometer becomes opaque to electrons for small k values. Our results suggest experiment tests not carried out so far to our knowledge.
    01/2009;
  • 13th Internation symposium on Capture Gamma Ray Spectroscopy and related topics; 08/2008
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    ABSTRACT: The most widely used theoretical internal conversion coefficient (ICC) tables are of Hager and Seltzer (HS), Rosel et al. and BRICC (Band et al. tables using BRICC interpolation code). A rigorous comparison of experimental ICCs with various theoretical tabulations is possible only when a large data on experimental ICCs is available at one place. For this reason, a compilation of all the available experimental ICCs, {alpha}{sub T}, {alpha}{sub K}, {alpha}{sub L} of E2 transitions for a number of elements in the range of 24{<=}Z{<=}94 is presented. Listing of experimental data includes 595 datasets corresponding to 505 E2 transitions in 165 nuclei across the nuclear chart. Data with less than 10% experimental uncertainty have been selected for comparison with the theoretical values of Hager and Seltzer, Rosel et al. and BRICC. The relative percentage deviation (%{delta}) have been calculated for each of the above theories and the average (%{delta}) are estimated. The Band et al. tables, using the BRICC interpolation code are seen to give theoretical ICCs closest to experimental values.
    13th Internation symposium on Capture Gamma Ray Spectroscopy and related topics; 08/2008
  • M Sainath, K Venkataramaniah, P C Sood
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    ABSTRACT: Bandhead energies of the low-lying two-quasiparticle (2qp) structures in the doubly odd nucleus 252Es are evaluated using a phenomenological rotor-particle model with the inclusion of residual interaction contributions. The results are compared with the experimental data from 256Md α-decay to deduce configuration assignments for the observed 252Es levels and to place the γ's seen in the α–γ coincidence experiments in this level scheme. The 252Es ground state is characterized as the 4+[7/2+[633]p ⊗ 1/2+[620]n] bandhead, consistent with all the known experimental data.
    Journal of Physics G Nuclear and Particle Physics 07/2008; 35(9):095105. · 5.33 Impact Factor

Publication Stats

25 Citations
46.29 Total Impact Points

Institutions

  • 1997–2013
    • 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
  • 1986
    • Centre for Earth Science Studies
      Tiruvananantapuram, Kerala, India