• Vinod Kumar

      Articles written in Bulletin of Materials Science

    • Separation characteristics of different size and density fractions in batch coal flotation

      M Vanangamudi C Vinod Kumar T C Rao

      More Details Abstract Fulltext PDF

      Batch flotation experiments were carried out using two coal samples to study the behaviour of each size and the density fractions in coal flotation. Different size fractions obtained from sizing of concentrates and tailing were subjected to float and sink analysis using organic liquids. The distribution curve technique was adopted to evaluate the performance of flotation. The results show that selectivity of flotation decreases with decrease in particle size. The specific gravity of separation is influenced more by the level of the frother dosage than by the collector dosage. The specific gravity of separation increases with increase in flotation time. The maximum value attained at infinite flotation time increases with decrease in particle size but the rate at which it is reached decreases.

    • Mixed conduction in charge transfer materials based on aromatic diamines and iodine having different mole ratios

      Ram Adhar Singh Vinod Kumar Singh

      More Details Abstract Fulltext PDF

      Mixed ionic and electronic conduction in charge transfer materials based on aromatic diamine electron donors (benzidine,o-tolidine (3,3′-dimethyl benzidine) andN,N′-diphenylbenzidine) with iodine in different mole ratios has been reported. The current-voltage and capacitance-voltage curves as a function of time and temperature have been obtained to determine the role of ionic conduction in electronic conductors based on charge transfer complexes. The compositional dependence of ionic transport numbers, diffusion parameters, ionic(σi) and electronic(σe) conductivities and thermal activation energies has been studied. Temperature and frequency dependence of AC impedance and related parameters have been studied to learn about the electrical conduction behaviour in these non-stoichiometric charge transfer materials. An electrochemical mechanism has been proposed to account for the ionic conduction in some of these complexes.

    • Hydrogen absorption/desorption characteristics of room temperature ZrMn2-𝑥Ni𝑥 system (𝑥 = 1.25-1.50)

      Vinod Kumar D Pukazhselvan A K Tyagi S K Singh

      More Details Abstract Fulltext PDF

      The present communication deals with the hydrogen storage characteristics of C15 laves phase ZrMn2-𝑥Ni𝑥 system tailored within the x values of 1.25 to 1.50. Drastic variations in thermodynamics of the hydride phase is observed for any little changes of concentration x within this narrow range. The most promising room temperature hydrogen storage materials are found to be formed within the range of 1.35 to 1.45 where ∼ 2.5 to 2.9 H/F.U. can be reversibly stored under the ideal operating conditions. The heat of the reaction is found to be ∼ 17 kJ/mol, which means these are promising candidates for stationary and short range mobile applications. The phase structural features and the thermodynamic aspects of all the materials are discussed in detail.

    • Facile synthesis of Zn/Cu and PANI modified layered double hydroxides with insights into structural memory effect property


      More Details Abstract Fulltext PDF

      The present study reports the successful synthesis of Zn/Cu layered double hydroxides (LDHs) by a simple hydrolysis route and detailed characterization using a wide variety of techniques, i.e., PXRD, FTIR, TGA, ICP-MS and SEM/EDX. The study proposes a facile and cost-effective method for exchanging the interlayer anion with the conducting polymeric anion (PANI) that results in a material with enhanced thermal, optical and electrical properties, which may be of interest in a variety of applications. The morphology, thermal stability and interactions of PANI-modified Zn/Cu LDH were compared with pristine LDH. In addition, the structural memory effect property of Zn/Cu lattice was examined, where after rehydration the calcined sample of as-synthesized LDH was successfully reformed into layered structure with good crystallinity.

  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2022-2023 Indian Academy of Sciences, Bengaluru.