• N SIVAKUMAR

      Articles written in Bulletin of Materials Science

    • Equation of state of refractory materials at very high temperatures—theoretical and experimental studies

      M Joseph N Sivakumar C K Mathews

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      This paper describes some of the theoretical and experimental studies being carried out at IGCAR on the equation of state of refractory materials like reactor fuels at high temperatures (>3000 K). The equation of state is primarily calculated by the principle of corresponding states. The influence of these equations of state on energy release in a hypothetical core disruptive accident in a fast breeder reactor is indicated. Details of an experimental facility based on laser induced vapourization mass spectrometry, which is being developed to measure the vapour pressures of materials at high temperatures is presented. Possible applications of this facility in other fields of materials research are indicated.

    • Growth, spectral, mechanical, electrical and optical characterization of guanidinium hydrogen succinate single crystal

      K KRISHNARAJ N SIVAKUMAR P PRAVEEN KUMAR

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      Slow evaporation method was employed to grow an organic crystal: guanidinium hydrogen succinate (GHS). Monoclinic structure of GHS was confirmed by single-crystal X-ray diffraction study and its space group was determined to be $P2_1/c$. Different functional groups present in GHS were estimated qualitatively by Fourier transform infrared analysis. The crystalline quality of the grown GHS was ascertained by high-resolution X-ray diffraction study. The UV–Vis absorption spectrum reveals a lower cut-off wavelength of 235 nm. The minimum absorption shows the wide optical transparency in the entire visible region.Work hardening co-efficient value ($n = 1.7$) shows that the GHS crystal belongs to soft material category. Behaviour of dipoles in the crystal was examined through dielectric study. The third-order nonlinear optical analysis wascarried out on GHS crystal through Z-scan technique. The nonlinear refractive index ($n_2$), nonlinear absorption coefficient ($\beta$) and third-order nonlinear optical susceptibility ($\chi^{(3)}$) were estimated to be $−5.78\times 10^{−8}$ cm$^2$ W$^{−1}$, $0.72\times 10^{−4}$ cm W$^{−1}$ and $8.09 \times 10^{−6}$ esu, respectively.

  • 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

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      Posted on July 25, 2019

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