The influence of intraseasonal oscillations on rainfall variability over Central Africa: case of the 25-70 days variability.

The influence of intra-seasonal oscillations (ISO) on rainfall in Central Africa (CA) during the March-May (MAM) season is assessed using the National Oceanic and Atmospheric Administration Climate Prediction Center daily gridded rainfall data. ISO indices are defined using the time series analysis of the first two principal components resulting from the empirical orthogonal function, applied to daily filtered outgoing longwave radiation. Based on these indices, a total of 71 strong Intraseasonal Events (SIEs) and 66 weak Intraseasonal Events (WIEs) were selected using threshold method.

Mineralogical, physico-chemical and ceramic properties of clay materials from Sekandé and Gashiga (North, Cameroon) and their suitability in earthenware production.

Clayey materials from Sekandé and Gashiga localities in the northern part in Cameroon traditionally used for pottery were studied. Eight samples were collected and investigated by XRD, IR, XRF, physical and firing properties from 900, 1000 and 1100 °C. In term of mineralogy, studied clays are rich in smectites, illite, kaolinite, quartz, feldspar and mica.

Study of water absorption in Raffia vinifera fibres from Bandjoun, Cameroon.

The study is focused on the water diffusion phenomenon through the Raffia vinifera fibre from the stem. The knowledge on the behavior of those fibres in presence of liquid during the realization of biocomposite, is necessary. The parameters like percentage of water gain at the point of saturation, modelling of the kinetic of water absorption, and the effective diffusion coefficient were the main objectives.