• Farooq Ahmad

      Articles written in Bulletin of Materials Science

    • Effect of curing conditions and ionic additives on properties of fly ash–lime compacts

      Saikat Maitra Farooq Ahmad Ananta K Das Santanu Das Binay K Dutta

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      In the present work the reaction between fly ash and lime in fly ash–lime compacts under water curing and steam curing conditions was studied thoroughly in relation to the processing conditions. Fly ash from different sources were collected, characterized, mixed with lime in different ratios and compacted. The compacts were cured with water and steam separately. The reduction in the free CaO content in these compacts was measured as a function of curing time and curing process. Role of two ionic additives, FeCl3 and MgCl2, on the reaction between fly ash and lime was also investigated by measuring the free CaO content. Kinetics of these reactions was studied by determining the reaction order and rate constants with respect to the free CaO content and it was observed that the curing conditions and additives affected the reaction kinetics significantly.

    • First-principles calculations of opto-electronic properties of IIIAs (III $=$ Al, Ga, In) under influence of spin–orbit interaction effects


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      In this article, we present first-principles calculations for structural and opto-electric properties of IIIAs (III $=$ Al, Ga, In) in the zinc-blende phase. Our calculations are based on the full potential-linearized augmented planewave method implemented in the WIEN2k code. We employed Perdew–Burke–Ernzerhof generalized gradient and modified Becke–Johnson approximations as exchange–correlation potentials. Our calculated structure parameters are found to be in reasonable agreement with the available literature. It was found that the inclusion of spin–orbit interaction effect shifts the conduction band minima towards the Fermi level and provides band gaps very close to their experimental values. The optical properties such as complex dielectric functions, complex refractive indices, reflectivities, energy loss functions, optical conductivities and absorption coefficients at varied frequencies were investigated in detail. We found that static real part of dielectric functions and refractive index decreases with increase in band gap. Our calculated critical point energies (eV) are consistent with the experimental results.

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