July 2021

Probability of dry and wet spells over West Africa during the summer monsoon season

This work aims at characterizing the conditional probability of single or consecutive dry and wet days in West Africa using the first-order Markov chain approach during the monsoon season (June to October). The results show that the probabilities of having a wet day (PW), a wet day preceded by another wet day (PWW) and a wet day preceded by a dry day (PDW) are stronger in regions where the rainfall is maximum (mountain...

Author(s): Jules Basse, Moctar Camara, Ibrahima Diba and Arona Diedhiou

August 2021

Reliability of vibratory indications during the follow-up of bearing spalling

In this work, spalling is naturally initiated on the bearing raceway during its operation on the test bench. The experimental procedure used consists of monitoring the deterioration of the ball bearing until its failure with an online acquisition of vibration signals. Vibration analysis is the method used to characterize the damage. In order to obtain a significant trend curve, spalling surface has been measured several...

Author(s): Omar DJEBILI and Oussama BERBRI

September 2021

On the effects of solar flare on geomagnetic components across all latitudes during solar minimum and maximum

The mutual dependence of solar flare and geomagnetic H and Z components during the period of least (2009) and maximum (2002) solar activity using archived and observed data were examined. Solar flares were identified by sudden ionosphric monitor (SIDMON) constructed by staff of Centre for Basic Space Sciences, University of Nigeria, Nsukka, Nigeria. However, SIDMON results were still confirmed by satellite data since it...

Author(s): Ernest Benjamin Ikechukwu Ugwu, Ugbor Desmond Okechukwu, Agbo Jonas Udoka