Declining availability of the prime economic species in the Nigerian timber market has led to the introduction of Lesser-Used Species (LUS) as alternatives. Their acceptability demands information on the technical properties of their wood. The aim of this study was to investigate the mechanical properties of Ficus vallis-choudae to determine its potential for timber. Three mature Ficus vallis-choudae trees were selected and harvested from a free forest area in Ibadan, Oyo State, Nigeria. Samples were collected from the base (10%), middle (50%), and top (90%) along the sampling heights of each tree, which was further partitioned into innerwood, centrewood, and outerwood across the sampling radial position. Investigations were carried out to determine the age, density, moisture content, impact strength, modulus of elasticity, modulus of rupture, compressive strength parallel-to-grain, and shear strength parallel-to-grain. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel-to-grain, and maximum compression strength parallel-to-grain for Ficus vallis-choudae at 12% moisture content were 20.4 N/mm2, 85.8 N/mm2, 709 N/mm2, 10.7 N/mm2, and 33.6 N/mm2, respectively. The study found the species to be dense with high strength properties in comparison with well-known timbers used for constructional purposes.
Eight tropical hardwood species were assessed for their density and radial, tangential and volumetric shrinkage, after which the relation between the density and different shrinkages was checked through correlation and regression. The results showed that the highest mean density was observed in Milicia excelsa with 900.63±50.13 kg/m³, followed by Afzelia africana, Nesogordonia kabingaensis and Nauclea diderichii with 831.25±41.67 kg/m³, 808.75±20.88 kg/m³ and 801.88±46.40 kg/m³, respectively. The mean density for Cassia simea was 781.88±27.71 kg/m³, Mansonia altissima 593.13±65.98 kg/m³, and Sterculia tragacantha 481.25±111.73 kg/m³, while the least density was observed in Treculia africana with 463.75±67.88 kg/m³. The highest volumetric shrinkage was observed in Nesogordonia kabingaensis with 14.71±2.28%, and the least in Cassia simea with 5.11±2.65%. It is concluded that there exists positive but weak correlation between density and the shrinkages in the eight tropical hardwood species.
This study investigates the properties of Lonchocarpus sericeus to determine its potential use for timber. Three matured trees of L. sericeus were selected from a forest located in Longe Village, Oluyole Local Government Area in Oyo State, Nigeria. Discs from the harvested trees were collected at the base (10%), middle (50%), and top (90%) and further partitioned into inner wood, center wood, and outer wood. An investigation was carried out to characterize the wood age, density, shrinkage, impact strength, modulus of elasticity, modulus of rupture, compressive, and shear strength. The ages were 28, 29 and 32 years. The mean wood density at 12 percent moisture content was 836.63 kg/m3, which shows that it belongs to the high-density wood category. The mean shrinkage values in the radial, tangential, and longitudinal directions were 2.50, 3.99, and 0.78 percent respectively; the volumetric shrinkage was 6.36 percent. These shrinkage values were indicative of good dimensional stability. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel to grain, and maximum compression strength parallel to the grain were 24.14, 114.18, 11,276, 12.76, and 47.16 N/mm2, respectively. End-use assessments suggest that the wood species can be used in similar applications as well-known timbers. The study found L. sericeus to be very dense with high strength in comparison to well-known timbers. It was observed that the mechanical properties of the species decrease from the base to the top and also increase from the outer wood to the core wood.
The use of coconut husk sawdust and tomato stem particles at varying blending proportion was examined for the production of particle board. Boards of dimensions 350 mm by 350 mm by 6 mm were produced (coconut husk dust, tomato stem particles) at different blending proportion and addition of additive (CaCl2 at different concentrations). The physical properties (water absorption and thickness swelling) and mechanical properties (modulus of rupture (MOR) and modulus of elasticity (MOE)) were investigated. Thickness swelling and water absorption were investigated at 24 and 48 hours. The results showed that boards exhibited mean values of 0.50% to 4.16% and 2.12% to 7.00% respectively of thickness swelling at 24 hours and 48 hours respectively and 13.6% to 25.2% and 17.6% to 29.1% of water absorption at 24 h and 48 h, respectively. The boards also exhibited means of 1.00 N/mm2 to 5.25 N/mm2 and 339 N/mm2 to 3430 N/mm2 for MOR and MOE respectively. An increase in the tomato particle content caused increase in water absorption and thickness swelling, resulting in the highest water absorption and thickness swelling values. Tomato stem and coconut husk dust can be used to produce cement bonded boards after pre-treatment with hot water and preferably both sieved.
Determining the variation of chemical properties of thermally treated Bambusa vulgaris is important to provide the information of the responses of the chemical constituents to the bamboo modification against biodegradation. This research was therefore conducted to determine the chemical properties of thermally modified Bambusa vulgaris. Two hundred and seventy (30 x 2 x 0.5 cm) bamboo strips dimension were thermally modified in a heat-chamber at 100, 110, 120, 130 and 140 °C each, for 10, 20 and 30 minutes, under constant pressure (220 N/m2) in factorial arrangement in completely randomised design with 5 replicates. Unmodified strips served as control. Chemical characteristics (cellulose, hemicellulose, lignin and ash contents) were determined using standard procedures. The mean variation range of the control to 140°C/30 minutes of the thermally modified samples is as follows; the cellulose value ranged from 46.46±0.11% to 42.19±0.18%, hemicellulose from 35.59±0.10% to 31.80±0.01%, lignin from 29.11±0.12% to 26.17±0.13%, ash from 0.92±0.02% to 0.63±0.01%; the study also revealed that there were decrease in each chemical constituent value varies from a lower to a higher temperature and time regime proportionally except in the lignin content. Increase in temperature and time of thermal modification reduced the chemical characteristics of Bambusa vulgaris which resulted to reduction in the level of sugar contents (cellulose) of bamboo which enables it to be less attractive to both fungi and termite attack hence extending the service life of bamboo in use.
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