Abstract： TM0.15Co0.1Zn0.75O nanoparticles with (TM=Ni and Mn) has been successfully synthesized by microwave assisted combustion synthesis method using urea as a fuel. The structural, morphological, compositional and Magnetic properties of these nanoparticles were investigated by X-ray Diffraction Machine (XRD), Scanning Electron Microscopes (FE-SEM JEOL-7001), Energy-Dispersive X-ray Spectroscopy (EDX), and Quantum Design Vibrating Sample Magnetometre (QD-VSM) respectively. The structural properties of both sample showed the formation of Wurtzite structure of ZnO, with nine prominent peaks in which the strong diffraction peaks appear in (100), (002) and (101), respectively, though there is a trace related to the Ni ions observed in the Ni samples. The average sizes of the nanoparticles were estimated using Debye-Scherrer’s equation. There is an increase in the average size between 32.65-34.23nm for Ni ion and a decrease in the size from 32.65-25.71nm for Mn ion. Scanning Electron Microscopes (SEM) showed that smaller crystallites of both samples have sizes smaller than 100nm, no indication of phase separation and little agglomeration was observed. Energy-dispersive X-ray Spectroscopy (EDX) confirmed that all the chemical composition of the samples tallies with the synthesis results. Moreover Magnetic measurement reveal that both samples exhibit a room temperature ferromagnetism though its higher in the sample doped by Ni ions.

Abstract： In this paper, a simple approach for general temperature decay function in the early phase of cosmic evolution is studied. New findings on the age of early developed galaxies demand for a re-thinking of the fate of young universe. The square-root scenario is compatible with an early aggregation of masses and an early beginning of the formation of galaxies and stars.

Abstract： This work presents the successful deposition of Lead Silver Sulphide (PbAgS) by simple chemical bath method under varying pH conditions. Varying pH was achieved using different volume concentration of ammonium hydroxide (NH4OH) solution. The final bath solution for the deposition of the films contained aqueous solutions of Pb(NO3)2, AgNO3, thiourea, TEA and EDTA. Pb(NO3)2, AgNO3 and thiourea served as precursors for Pb2+, Ag+, and S2- respectively while EDTA and TEA were used as complexing agents. NH4OH served as pH adjuster. The deposited film properties were characterized for optical and electrical properties using a Janway UV – VIS spectrophotometer and 4 Point Probe (Keithley Four Point Probe: Model 67005). From the spectral analysis of absorbance, other optical properties such as transmittance, reflectance, refractive index, and extinction coefficient and band gap energy were obtained. The films show high absorbance in the UV region and high transmittance in the VIS – NIR regions, while reflectance is generally low. The films showed direct band gap energy range of 1.89 eV – 2.30 eV. The result showed that band gap decreased as pH increases. Film thickness increased from 493.83 nm to 945.52 nm as pH increases. Electrical properties of the films showed that the deposited PbAgS thin films are semiconducting films with electrical conductivity within the range of 1.337 × 10-3 (s/cm) and 9.334 × 10-3 (s/cm). Electrical conductivity of the films were found to increase as pH increases from 10.30 to 11.20.

Abstract： In the present work, an approximation novel method was used to determine both the crystallite size and micro-strain from XRD profile for deformed and non-deformed 3004 Al alloy by determining the total physical broadening, the crystallite size broadening and the strain broadening. Aluminum and its alloys are widely used in aircraft automotive and in construction industries because of their desirable physical properties. The estimated crystallite size and micro-strain obtained via this approximation method were in a good agreement with the full width at half maximum (FWHM) and the strain broadening at each peak (111), (200), (220), (311), (222) at the corresponding Bragg angles. The variation of strain broadening, defect density and stored dislocation energy with thickness reduction seems to be an exponential growth, according to the increasing of the dislocation density as predicted theoretically.