Among the rare earths, Cerium (Ce) and several of its compounds find a wide range of industrial applications. Cerium is also that most abundant of the rareearth elements, being found in several minerals (e.g. monazite) in high proportions. It is generally extracted from fractions obtained in the processing of these minerals. Potassium stearate has been used as one of the extracting agents for Ce (IV). In this study, the feasibility of extractingcerium both as Ce (IV) and Ce (In), by precipitation with sodium and potassium salts for stearic, lauric, palmitic, capric, oleic acids; mixture of these acids and saponified coconut oil was investigated. The main objtive was to study the extractibility of Ce (III) and Ce in coconut oil saponified by sodium hydroxide (NaOH); because both coconut oil and sodium hydroxide are available in Sri Lanka, and the method if successful could be economically used on a large scale. The extractibilities of Ce (111) and Ce (IV) ions were determined on a quantitative basis, by their conversion into acylates in each of the above systems over a range of pH values. The results showed that (a) the extent of extraction of Ce (III) and Ce (IV) are reasonably high in the saponified coconut oil, (b) Ce (IV) is best extracted with sodium salts and Ce (111) with potassium salts at a pHvaluearound 5, (c) more than 65 % of Ce (111) can be extracted by sodium salts in the pH range of 3.5-6.8 under carefully controlled conditions. Therefore coconut oil saponified by sodium hydroxide can be considered as a promising extracting medium for Ce (IV) ions especially, while the oil saponified by hydroxides of both sodium and potassium is promising for the extraction of Ce (111) ions.

The error probability of DPSK signals in Nakagami fading with EGC diversity reception is analyzed. The error rate is expressed as a ( ) 1 + L -fold integral that contains only simple mathematical functions for L channel reception. The multiple integrals are easily evaluated with the GaussLegendre quadrature. Numerical values for the error rates of binary, quaternary and octonary DPSK signals are presented for several fading severity levels.