Browsing by Author "Mhinzi, G. S."
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Item Intra-Species Variation of the Properties of Gum Exudates from Two Acacia Species of the Series Gummiferae(Elsevier, 2008) Mhinzi, G. S.; Mghweno, L. A. R.; Buchweishaija, JosephGum exudates from Acacia drepanolobium and A. kirkii ssp. kirkii var. kirkii from Tanzania have been analyzed and the intra-species variation of their properties evaluated. The results show that inter-species variation of the properties of the gum exudates from the two species exist, whereas only some parameters show intra-species variation. The specific optical rotations of the gum exudates varied from +72.0° to +94.6° for A. drepanolobium and +29.2° to +38.0°, for A. kirkii ssp. kirkii var. kirkii. Likewise, the acid equivalent weights (AEWs) varied from 832 to 1659 for A. drepanolobium and 663 to 1199 for A. kirkii ssp. kirkii var. kirkii. Intra-species variation for the tannin content was also observed for the species studied, whereas no intra-species variation was observed for the nitrogen and methoxyl contents. The results in this study show that the variation of the properties among the batches of commercial Acacia gum may be due to admixture of gums from different Acacia species, as well as intra-species variation.Item Natural Products as a Source of Environmentally Friendly Corrosion Inhibitors: The Case of Gum Exudate from Acacia seyal var. seyal(2008) Buchweishaija, Joseph; Mhinzi, G. S.The inhibitive effect of the gum exudate from Acacia seyal var. seyal on the corrosion of mild steel in drinking water was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results obtained show that gum exudates could serve as effective inhibitors for the corrosion of steel in drinking water network. The percentage inhibition increases with increasing the concentration of the gum at 30 oC. The percentage inhibitor efficiency above 95 % was attained at gum concentration ≥400 ppm. The corrosion rates of steel and inhibition efficiencies of the gum exudates obtained from impedance and polarization measurements were in good agreement. Potentiodynamic polarization studies clearly reveal that the gum behaves predominantly as an anodic inhibitor. The study also shows that the inhibition efficiency was insignificantly affected by the temperature rise of the medium.Item Port Electrochim(2008) Buchweishaija, Joseph; Mhinzi, G. S.