January 2021

Evaluation of simulated rain-based attenuation techniques at k-v frequency bands for satellite services under different modulation techniques over Southwestern Nigeria

Rain-based attenuation (RBA) is a major deteriorating factor affecting radio wave signals operating at microwave and millimetre wave bands for a typical Earth-Space Communication Link (ESCL). Although the international telecommunication union (ITU) recommended a standard model for predicting RBA along the terrestrial and ESCL, the technique underperforms in tropical environments. However, the model can be supported by...

Author(s): J. S. Ojo, K. D. Adedayo and A. N. Uchegbu  

February 2021

Stability and elastic anisotropy of diamond related C8-yBy materials

A number of potentially super-hard materials were examined using ab-initio methods. Low Gibbs free energy polymorphs of diamond-like materials for y = 0 to 7 in the stoichiometric type C8-y By, were identified at absolute zero of temperature. These were proposed as possible super-hard materials with useful applications. The materials with y = 0 to 3, that is, diamond (C), cubic C7B (c-C7B), rhombohedral C3B (r-C3B) and...

Author(s): G. Samukonga, A. Habanyama and N. K. Mumba  

February 2021

Test of velocity-displacement estimation using variometric method under the condition of ionospheric scintillation during equinoctial months of solar maximum period 2012

The Global Navigation Satellite System (GNSS) technologies have made significant contribution to seismology studies. Some processing strategies are well known, like real time PPP and DGPS techniques. These two methods have been widely used for GNSS based seismic activities monitoring. The first method requires accurate models of GNSS measurement errors to achieve accuracy in centimeter (cm) and need convergence time in...

Author(s): Asnawi Husin, Buldan Muslim, Joni Efendi and Dyah R. Martiningrum  

March 2021

Evaluation of the anti-microbial efficiency of scrap metal-based coagulant and local salt modified-biomaterials for point-of-use water treatment

The anti-microbial efficiency of a composite material formulated from a scrap metal-based (iron (III) sulphate) coagulant and indigenous salt (NaCl) activated biomaterials (coconut shell carbon and counter wood) were evaluated by using the composite materials as coagulant and disinfectant adsorbent by treating borehole water and river samples at point-of-use. The results of the microbial analysis of the untreated and...

Author(s): David Obasi Igwe, Joseph Nwode Afiukwa and Frank Ikenna Nwabue