Paleo-environmental deduction from pebble morphometry and textural studies of sandstone deposits of Isuochi and Environs, Anambra Basin, South Eastern Nigeria

Textural analysis and pebble morphomentric were carried out on the sandstone deposits of Isuochi area in Anambra Basin, in an attempt to reconstruct the paleoenvironment of deposition. Field observation shows that the sandstone samples, collected from various locations were analyzed for sieve analysis, while two hundred fresh quartz pebbles that are greater than 2.00mm in diameter were collected for pebble morphomentric. Morphomentric parameters include; elongation ratio, flatness index, oblate index, and maximum projection sphericity were computed. Bivariate plots of Maximum Projection Sphericity against Oblate Prolate Index show that about 69% of the pebbles are of fluvial origin,while 31% is surf, bivariate plots of Flatness Index against Maximum Projection Sphericity show that about 57% is of fluvial origin, while 43% show surf; these imply that the associated pebbles are of fluvial origin. Bivariate plots of sandstone textural parameters such as skewness against standard deviation also suggest that the sediments are more of fluvial origin while multivariate parameter shows partly shallow marine environment. Keywords: Pebble Morphometry, Oblate-Prolate Index, Paleoenvironment.

Multivariate-parameter optimization of the alkaline peroxide mechanical pulp (APMP) process for larch (Larix gmelinii Rupr.) using Box-Behnken design

The study is aiming at the finding of optimal pulping conditions for the alkaline peroxide mechanical pulping process applied to larch in terms of brightness (% ISO) and tensile strength (TS). Based on three variables, the Box-Behnken experimental design was applied to determine the effects of the first-stage and second-stage dosages of H2O2 and the impregnation temperature on % ISO and TS. The equations based on the quadratic regression analysis were developed, which describe the response behaviors as the simultaneous functions of the selected independent variables. The best brightness achieved was 75.4% ISO under the following conditions: first-stage H2O2 3.5%, second-stage H2O2 3.54%, and impregnation temperature 81.4°C. The best TS (37.2 N·m g-1) was found under the following conditions: first-stage H2O2 2.4%, second-stage H2O2 3.9%, and impregnation temperature 90°C.