A facile and rapid microwave-assisted combustion method was used to synthesis nanocrystalline SnO₂ powders, through dissolution of tin nitrate (as oxidant) and glycine (as fuel) as starting materials and water as solvent and then heating the resulting solution in a microwave oven. The study suggested that application of microwave heating to produce the nanosize SnO₂ was achieved in a few minutes. The structure and morphology of the as-prepared combustion products were in...

In this work, Raman spectra and dielectricity–temperature dependence measurements were used to investigate the B-site order degree in CuO-doped Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ ferroelectric ceramics. The measurement results indicated a typical relaxor characteristic for all samples. With the increasing of CuO doping content, the B-site order degree increased first and then decreased. However, the frequency dispersion and the relaxation degree ...

Geopolymer composites containing woven cotton fabric (0–8.3 wt%) were fabricated using the hand lay-up technique, and were exposed to elevated temperatures of 200 ℃, 400 ℃, 600 ℃, 800 ℃ and 1000 ℃. With an increase in temperature, the geopolymer composites exhibited a reduction in compressive strength, flexural strength and fracture toughness. When heated above 600 ℃, the composites exhibited a significant reduction in mechanical properties. They also...

Various bulk and transparent glasses were prepared by rapid melt quenching technique in the glass system 55[(Pb_xBi_1-x)TiO₃]–44[2SiO₂B₂O₃]–La₂O₃ (x = 0–0.7). The X-ray diffraction (XRD) studies of the glass samples confirmed the amorphous nature. The differential thermal analyses (DTA) were carried out from room temperature to 900 ℃ with a heating rate of 10 ℃/min. The DTA...

The aim of this work was to study the influence of the different synthesis processes on microstructural and morphological characteristics and distribution of hydroxyapatite-bioactive glass (HAp-BG) composite nanopowders obtained by sol–gel method. HAp-BG composite nanopowders with 20 wt% bioactive glass were prepared using a sol–gel method via four routes: (I) mixing the prepared HAp solution with BG solution before aging time; (II) mixing the prepared BG solution with the prepared HAp gel af...

In the present research work, frequency dependent electrical properties of tungsten bronze structured compounds Na₂Pb₂R₂W₂Ti₄Nb₄O₃₀ (R = Nd, Sm) are reported. X-ray diffraction (XRD) study of polycrystalline ceramic samples confirms the formation of compounds with orthorhombic structure. Analysis of frequency dependent electrical data in the framework of modulus and conductivity formalism suggests the presence of the...

We develop a theoretical model for quantitative analysis of temperature-dependent thermoelectric power of monovalent (Na) doped La_0.97Na_0.03MnO₃ manganites. In the ferromagnetic regime, we have evaluated the phonon thermoelectric power by incorporating the scattering of phonons with impurities, grain boundaries, charge carriers and phonons. In doing so, we use the Mott expression to compute the carrier (hole) diffusion thermoelectric power (