The corrosion inhibition of Al and its alloys is the subject of tremendous technological importance due to the increased industrial applications of these materials. This study reports the corrosion inhibition of AA8011 aluminium alloy in acidic solutions using Newbouldia leavis leaf extract by way of gravimetric measurements. It was shown that the presence of Newbouldia leavis leaf extract inhibited the corrosion of aluminium in the test solutions and the inhibition efficiency depended on the concentration of the plant extract as well as on the time of exposure of the aluminium samples in H 2 SO 4 solutions containing the extract. The experimental data complied to the Langmuir adsorption isotherm and the value and sign of the Gibb's free energy of adsorption obtained suggested that inhibitor molecules have been spontaneously adsorbed onto the aluminium surface through a physical adsorption mechanism.

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The effect of Euphorbia hirta and Dialum guineense leave extracts on the corrosion of aluminium in 0.25M NaOH was investigated using gravimetric technique. It was shown that the presence of Euphorbia hirta and Dialum guineense leave extracts inhibited the corrosion of aluminium in the test solutions and that the inhibition efficiency depended on the concentration of the plant extract as well as on the time of exposure of the aluminium samples in 0.25M NaOH solutions containing the extracts. Dialum guineense extract shows the best inhibition capability for aluminium corrosion in sodium hydroxide, probably, this is due to the planer orientation of the adsorbed extract molecules. Inhibition efficiency of the inhibitors tested increases with decreasing sodium hydroxide concentrations. The experimental data complied to both Langmuir and Temkin adsorption isotherms and the value and sign of the apparent activation energy of adsorption obtained suggests that inhibitor molecules have mixed inhibition mechanism.

An inclined box-type solar cooker employing tracking reflectors with dimensions 700mm x 440mm x 280mm, has been successfully designed and fabricated. The detachable reflectors, which were mounted on the box cooker, were suitably positioned in an east-west configuration on an inclined framework. This automatically tracks the apparent motion of the sun within 15 minutes time interval so as to align with the earth’s rotation when displayed under the sun. Thermal performance of the inclined box-type solar cooker has also been compared with that of a conventional box-type solar cooker whose dimensions and make are identical to the inclined box cooker. Testing of the tracking box type solar cooker has been carried out with load and without load conditions at Federal University of Technology Owerri, Imo State, located at Latitude 5oN, Longitude 7oE, Altitude 156m (Altitude 511ft) and 12km south of Owerri capital territory. Experimental results obtained from the field test show that the inclined box-type solar cooker with tracking reflectors attained temperature of 94oC, with efficiency of 93% and boiled water for 1hour 28 minutes. The conventional box-type solar cooker attained a temperature of 91oC, with efficiency of 90.9% and boiled water for 1hour 36 minutes. The tracking box cooker was found to be more efficient and effective than the conventional box cooker. Meteorological variables like Air Temperature, Irradiance, Relative Humidity and Wind speed were also obtained to investigate their effects on the performance of the box cookers.