Abstract: The corrosion inhibition effect of potassium thiocynate (KSCN) on mild steel in deareated 1 M hydrochloric acid and 0.5 M sulphuric acid solution at 30 o C was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The corrosion rates of steel and the inhibition efficiencies of the KSCN were calculated. The results showed that KSCN act as good inorganic inhibitor and the inhibition efficiencies were significantly increased by increasing the concentrations of KSCN. Polarization curves showed that KSCN acts as mixed type inhibitor. The impedance response indicated that the corrosion process occurs under charge transfer control. Electrochemical techniques give more accurate results other than the weight loss method.

Abstract: The morphological and anatomical study of three Nigerian species of Strychnos: S. spinosa, S. innocua and S. usambarensis was carried out. The leaves are dorsiventrally flattened, petiolate, with distinct palmate venation. The transverse section of leaf lamina revealed uniseriate epidermis with double-layered palisade mesophyll and loosely arranged spongy mesophyll. Rosette crystals were found in the mesophyll of S. spinosa and S. usambarensis. Stomata are hypostomatic and the measurement of the length of guard cells of S. innocua differed from those of S. spinosa and S. usambarensis. Petiole anatomy revealed seven variously sized and separate vascular bundles in S. innocua and S. spinosa but with a single arc shaped bundle in S. usambarensis.