Termite Resistance of Thermally-Modified Dendrocalamus asper (Schultes f.) Backer ex Heyne
The effects of thermal modification on the resistance of Dendrocalamus asper against Microcerotermes losbañosensis were investigated after exposure to virgin coconut oil at 140–200 °C for 30–120 min. The results showed that heat treatment significantly improved bamboo’s resistance to termites based on mass losses and visual observations. The enhancement was highest at 200 °C. Prolonged treatment had a positive effect on the resistance at lower temperatures only.
Effect of heat treatment using palm oil on properties and durability of Semantan bamboo
This paper investigates the effect of heat treatment on Semantan bamboo (Gigantochloa scortechinii) with emphasis given to their properties and durability. Matured four-year-old bamboo culms were harvested and subjected to high temperature condition using palm oil as a heating media. Two groups of samples, green and air-dried, were used. The temperatures applied were 140Â°C, 180Â°C and 220Â°C, with exposure duration of 30, 60 and 90 min, respectively. The results of the investigations show that the heat-treated bamboos retained most of their original physical and strength properties after undergoing the heat treatment. Green or air-dried bamboo culms can be dried to an MC of 6-7% within 2-3 h of treatment. The basic densities of bamboo were found to improve slightly by the heat application. The overall strengths properties of the heat-treated bamboo were found to decrease. The modulus of elasticity in the bending strengths was reduced between 2 and 33% in the green- and 6-9% in the air-dried conditions. For the modulus of rupture in the bending strengths, the value was reduced between 1 and 23% in green- and 4-16% in air-dried conditions. The compression strengths were reduced in the range between 2 and 3% in green- and 2-35% in air-dried conditions. The shear strengths were reduced in the range between 16 and 24% and 12-24% in in green- and air-dried conditions, respectively.
Investigations on the rôle of organic matter in plant nutrition
1. As the result of decomposition of green manure in a swamp soil, the coarse fractions (including coarse and fine sand) of the surface layer (first 3 inches) decreased by 11·2 per cent. while the fine ones (silt+clay) increased by 9·8 per cent. in the course of 43 days. The effect was less pronounced in the manured soil maintained at 60 per cent. saturation, while no alteration was to be noticed in the case of the unmanured specimens. 2. Treatment with dilute hydrochloric acid prior to dispersion had no appreciable effect on the estimates of mechanical composition obtained in the different cases. Loss in solution was also comparatively small. 3. The silica-sesquioxide ratio increased slightly as the result of decomposition of green manure in swamp soil. The composition of the fine fractions was also altered, the total percentages of the oxides of iron, aluminium and silicon increasing from 90·5 to 99·3 in the course of 71 days. 4. The practical significance of the above and related observations has been discussed.