WOOD RESEARCH Volume 62, Number 3, 2017
Partson Tinarwo, Temesgen Zewotir, and Delia Nort

Modelling the effect of eucalyptus genotypes in the pulping process with generalised additive models and fractional polynomial approaches

The advent of lean (waste reduction), six sigma (process variation minimisation) and proper raw material selection are the essential challenges to achieve the required quality on the overall industrial processes. Accordingly a laboratory experiment for the dissolving wood pulping process was conducted on nine Eucalyptus genotypes to measure the change in lignin, viscosity and α-cellulose at each of the six pulp processing stages. The changes to these properties were modelled using the Generalised Additive Models (GAM) and Fractional Polynomial (FP) models. These models proved to be equally important in their unique ways and produced complementary results. The results revealed that Emearnsii genotype produced the best results for both α-cellulose and viscosity, while Enitens genotype was selected for the optimal lignin reduction. Egrandis genotype is the only genotype that proved to have adverse effects on the viscosity property.

WOOD RESEARCH Volume 63, Number 6, 2018
Ajuziogu G.C., Onyeke C.C., Ayogu V.O., Asuzu C.U., Urama D.C., and Odoh N.V.

Treatability indices of some plant species of fabaceae in Nigeria

The hydraulic conductance as estimated by Hagen Poiseuille equation was tested on five Nigerian timber species: Brachystegia nigerica, Afzelia africana, Periscopsis elata, Erythrophleum suaveolens, and Daniella oliveri using spent-engine oil (SAE 40), diesel, kerosene and solignum. The wood of Brachystegia nigerica and Afzelia africana gave more conductance (penetrability) to kerosene, diesel, solignum and spent-engine oil than the other three. The wood of Brachystegia nigerica and Afzelia africana gave the highest vessel lumen radius of 0.18±0.06 mm and 0.12±0.01 mm respectively, while Daniella oliveri, Erythrophleum suaveolens and Pericopsis elata gave the lowest vessel lumen radius 0.09 ± 0.01 mm, 0.07±0.01 mm and 0.05±0.002 mm respectively. The less viscous oils: kerosene, solignum and diesel with viscosities 0.015, 0.019, and 0.043 centipoises respectively at 28°C showed more penetrability than the more viscous spent-engine oil of 2.92 centipoises. There is a positive correlation between the vessel lumen radius and hydraulic conductivities of the four treatment fluids (P ≥ 0.05).