Morsy M. Abou-Sekkina

Mechanism of thermal decomposition and γ-pyrolysis of aluminum nitrate nonahydrate [Al(NO3)3·9H2O]

Thermal decomposition and γ-pyrolysis of aluminum nitrate nonahydrate have been investigated by means of X-ray, IR, UV/VIS, TGA and DTA. All the experimental results obtained before and after γ-ray irradiation elucidated the decomposition mechanism.

The thermal stability and temperature dependence of the electrical conductivity of Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) indazole Schiff base complexes

Abstract The thermal stabilities of the indazole Schiff base complexes of Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) were studied. The stabilities are discussed in terms of structure and type of metal ions. The activation energies E α of the different processes were evaluated and discussed in accordance with the structure of the complexes. The electrical properties of the metal complexes were also investigated with reference to the types of metal ion and organic ligand.

Thermophysical properties of gamma-irradiated LaFeO3 and YFeO3 orthoferrites

In the present work, LaFeO3 and YFeO3 orthoferrites were carefully prepared using the solid state high temperature ceramic and sintering technique. On these two materials, numerous measurements were applied before and after γ-absorbed dose (1.24 Mrad) namely, X-ray diffraction (XRD), DC-electrical conductivity, UV/Vis, IR, Mössbauer effect and EPR. Results obtained were explained, interpreted, and discussed in detail on the basis of lattice structure of the new perovskite investigated and the interaction of γ-radiation with the investigated materials. Finally the γ-induced functions are evaluated for electrical conduction, Mössbauer effect and EPR for the first time.

Exploration of a cuprate superconductor YBa2Cu3O7−δ as a catalyst and industrial antipollutant

The kinetics of oxidative decomposition of Erythrosin B dye using the 123-copper superconductor was studied carefully in aqueous solution under condition of pseudo first-order reaction. Many of the kinetic parameters were investigated in this paper. Results obtained indicated that the rate of oxidative decomposition of Erythrosin B dye was found to be pH-dependent. Furthermore, the effect of added KCl and SDS anionic surfactant on the reaction rate reveals an increase in the case of KCl and its decrease in the case of the SDS surfactant. A mechanism was proposed and the activation parameters were calculated for this oxidative decomposition reaction.

Further investigations on the thermoelectrical and photochemical properties of 2,5-distyrylpyrazine (DSP) and azodiisobutyronitrile (AIBN) single crystals

Abstract DC-electrical conductivity has been studied for fresh and partially photopolymerized 2,5-distyryl-pyrazine (DSP) single crystals of the α-modification. α-DSP crystals show semiconductivity with a positive activation energy for DC-electrical conduction, E a = 0.86 eV. The specific conductivity, σ, falls and E a increases as photopolymerization proceeds due to the consumption of delocalized π-electrons in the formation of cyclobutane rings and also the shrinkage accompanying photopolymerization. This behavior has been contrasted to that of azodiisobutyronitrile (AIBN) crystals. AIBN crystals show semiconductivity for fresh samples that changes to semi-metallic conductivity upon irradiation (λ ex = 365 or 337 nm).

Counter courrent compensation of double doped Pb(Zr1−x, Tix)O3 piezoelectric ceramics

Abstract Various compositions of pure Pb(Zr/Ti)O3 having Zr/Ti ratio ranging from 50/50 up to 58/42 were prepared by the usual ceramic technique and firing at 1400°C. The prepared materials were single doped with 0.1 wt.% lanthana and douple doped with (0.1 wt.% lanthana + 0.1 wt.% neodymia). Measurements of dielectric properties (constant and anisotropy), piezoelectric properties and Youngs modulus were conducted as a function of Zr/Ti ratio and type of doping. The obtained results were discussed on the bases of the effects of varying (Zr/Ti) ratio and single doping with lanthana on forcing of Pb(Zr/Ti)O3 normal lattice to a defective crystal lattice having high dielectric values. Further lattice strain and defects were induced by static stress causing a generation of high piezoelectric charges at the surface of the specimens. A conclusion had been attained that Pb(Zr0.55, Ti0.45)O3 doped with 0.1 wt.% La2O3 constitutes the optimum composition for attaining a better quality ceramic dielectric and piezoelectrics to be used in industry for converting mechanical energy (static stress) to electrical energy (piezoelectric charges). Thus, it was possible to make use of counter doping (compensation phenomenon) to control the desired properties and to get rid of the undesired impurities in ceramic bodies in industry which would be very profitable economically instead of chemical purification or other destructive means.

New Thorium-Doped YBa2(1 − x)Sr x Th x Cu3O7 − δ High-Tc Superconductors

Thorium-doped YBa2(1 − x)SrxThxCu3O7 − δ high-Tc ceramic superconductors (with x = 0.1, 0.15, 0.2, and 0.3) have been carefully prepared by the usual ceramic procedure and sintering technique, with intermediate grindings and annealing under a stream of compressed-air atmosphere. The structural parameters of the prepared samples are calculated and interpreted using X-ray diffraction analysis. The electrical properties are also carefully investigated in the present work using the four-probe technique. Results obtained were compared, explained, interpreted, and discussed in detail; meanwhile, the major goal of the present work and promising deductions are attained at.

Crystal Structure and Superconductivity of (Hg0.5Pb0.5)Sr2(Sr1-xLax)Cu2Oz.

An Hg-based superconducting cuprate (Hg 0.5 Pb 0.5 )Sr 2 (Sr 1-x La x )Cu 2 O z has been synthesized. X-ray diffraction patterns indicate that the 1212-compound exists only in a narrow composition range of 0.45 ≤ x ≤ 0.55. Rietveld refinement based on the space group P4/mmm gives tetragonal lattice parameters of a = 3.869(7) and c = 12.14(2) A and a chemical composition of (Pb 0.50 Hg 0.28 Cu 0.22 )(Sr 0.85 La 0.56 ) 2 (Sr 0.44 La 0.56 )Cu 2 O 6.56 for the compound of x = 0.55. Electrical resistivity measurements show that the sample with x = 0.55 becomes superconducting after annealing in O 2 with onset T c of 97K.

Manganese-Nanoparticles Substitutions on the Vanadium Sites of Bi-Sr-Vanadate Aurivillius Ceramics

The aurivillius phase of Mn-substituted samples with general formula Bi2SrV2−𝑥Mn𝑥O9, where 𝑥=0.05,0.1,0.2,0.3, and 0.6 mole were prepared by solid-state reaction technique and ceramics procedures. The X-ray structural measurement analysis confirmed the formation of single-phase-layered hexagonal structure which is observed in all samples. The thermal stability and phase change of the green powders were studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). SEM revealed that the average grain size increases with increasing Mn content. The infrared absorption spectra recorded a series of vibrational modes within the range of 400–1600 cm−1 were investigated. The present work also studied the effect of Mn-doping concentration interactions on both DC-electrical conductivity and ESR spectra.

Further investigations on the thermophysical properties of gamma-irradiated urania-doped orthoferrites

Abstract(Y1.85−U0.15) FeO3 orthoferrite was carefully prepared using the solid-state high temperature ceramic and sintering technique. On this orthoferrite, numerous measurements have been undertaken before and after 1.24 Mrad γ-absorbed dose, namely X-ray diffraction (XRD), DC-electrical conductivity versus temperature, UV/Vis. absorption, IR absorption, Mössbauer effect (ME) and EPR. In the present work the results obtained were explained, interpreted and discussed in details on the basis of lattice structure of the new perovskite investigated and the interaction of γ-radiation with the orthoferrite lattice.