Optical Properties of Titanium Substituted Manganese -Zinc Ferrite System- Mn0.8+X Zn0.2tixfe2-2xo4 with X=0.10 (Published)
Titanium substituted Manganese-Zinc ferrite (Mn0.8+x Zn0.2TixFe2-2xO4 with x=0.10) was synthesized thermo chemically by solid state method at different treating temperatures. Basically, the substitution cause a rearrangement of Fe+3 ions into the two preexisting octahedral and tetrahedral sites. The X-ray analysis confirms the formation of single phase cubic spinel structure. The lattice constant decreases slightly and porosity increases with increase in sintering temperature. They can be disrupted into smaller particles by shear forces generating mechanical stress gradients. A characteristic feature of all solid-state reactions is that they involve the formation of product phase(s) at the interfaces of the reactants. UV-VIS analysis of the sample was carried out. Tunable band gaps can be obtained by varying annealing temperatures. The optical constants of refractive index, extinction coefficient, normal-incidence reflectivity, and absorption coefficient showed systematic variation with temperature. The dispersion of refractive index was analyzed by the Wemple-DiDomenico single-oscillator model.
Keywords: Dispersion, MnZnTiFeO, Wemple-DiDomenico model, band gap energy, refractive index
Effect of Secondary Radioclimatic Variables on Signal Propagation in Nsukka, Nigeria (Published)
This study presents the effects of Radioclimatic variables on signal propagation in Nsukka, Nigeria. The primary Radioclimatic data used in the study include temperature, pressure and humidity or water vapour pressure, while secondary radioclimatic data includes refractivity (N), refractive index (n) and effective earth’s radius (k-factor). The measurements of the primary variables were made at time interval of 30 minutes daily from August 2013 to July 2014. The results obtained show seasonal variation of the temperature and relative humidity. This leads to the increase in the values of radio refractivity and refractive index. The results also, show that the k-factor values for those months were at the range 1.555 – 1.653. This high values of k-factor is an indicator to the possible causes of signal interference in the study area.
Keywords: Nsukka, Refractivity, k-factor, refractive index