A number of common tropical timbers have been subjected to thermal analytical investigation as part of a wider research programme under air atmospheric conditions. Thermal parameters obtained were correlated with oven‐dry densities of the timbers. Two well‐defined pyrolysis stages have been observed which occur over the temperature ranges 201–426°C and 397–557°C. The kinetics of the thermal degradation of the timbers were obtained using Broido's analytical procedure. These results were interpreted on the basis of the known mechanism of pyrolysis and the calculated kinetic parameters were discussed within the context of other published values for cellulose.
ABSTRACT:In this work, we extracted data from Optical Properties of Aerosols and Clouds (OPAC) using FORTRAN program to model the effect of soot on optical depth, scattering coefficient, absorption coefficient, single scattering albedo, extinction coefficient and asymmetry parameter at spectral range of 0.25 to 1.00 m for eight different relative humidities (RHs) (0, 50, 70, 80, 90, 95, 98 and 99%). The concentration of sootwas varied as 1.10 × 10 , 1.20 × 10 and 1.30 × 10 while the insoluble and water soluble were kept constant at 1.50 and 15,000 cm -3 respectively. The optical parameters were used to determine the Radiative forcing (RF). Origin 50 software was used to plot the graphs. SPSS 16.0 Software was used to determine the Ångström exponent, and Curvature, 2. The reflects the dominance of fine-mode particles while 2 at 0% RH reflects the dominance of coarse-mode particles and at 50-99%RHs reflects the dominance of fine-mode particles, the turbidity, indicates a relatively hazy atmosphere, the Aerosol Optical Depth (AOD) show a relatively higher value indicating a polluted urban air, the asymmetry parameter, g falls between 0.64 and 0.77. However, from our graphs of Radiative forcing against wavelength, we report that addition of soot concentration reflects warming effect; therefore soot has a relatively high absorption coefficient.
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