Presence Of Primary Particles Research Articles

Short note: On petrographically differentiating the anatomical characteristics of saprotrophied and carbonised inertinite group macerals

The use of inertinite macerals as palaeoenvironmental and palaeoclimatic indicators is reliant on understanding their origin. Criteria to distinguish between carbonisation and pyrolysis, or saprotrophy resulting from fungal degradation, are not always clear. Without the presence of primary particles in coal, such as fungal sclerota, hyphae, char, and fly ash, the origin of inertinites is difficult to distinguish. This short study provides an insight into basic anatomical characteristics, which differentiate saprotrophied and carbonised inertinite group macerals. Modern plant matter and Permian phyterals are compared petrographically to observe changes in the macerals at a cellular level. Saprotrophic effects include thickening of the cell wall and cellular damage, delignification of the cell wall and cross ray piths, and the irregular oxidation radiating from xylem tissues. These characteristics are not observed in carbonised inertinites that show enlarged ray cells and the shrinking and homogenisation of cell walls. The simple differentiation between these characteristics in inertinites can greatly affect the palaeoenvironmental interpretations linked to the presence of inertinites in coal.

Steric stabilization of St�ber silica dispersions using organosilanes

Organosilanes of the general formula RxSi(OR′)4−x (where R is an alkyl group and R′ = CH3 or CH2CH3) were used to sterically stabilize hexane dispersions of submicrometre silica spheres. The dispersions were characterized according to sediment volume results. For 0.5μm silica particles, the sediment density increased by more than a factor of three up to 50 to 55% of theoretical in the presence of organosilanes with 12 or more carbons in the R group. Solid-state13C nuclear magnetic resonance was used to characterize the powder-dispersant interaction; this technique can distinguish between carbons in the R group of the organosilane and residual organic groups in the silica. Scanning electron micrographs of filter compacts were used to further characterize the dispersions and indicated the presence of primary particles as well as small agglomerates.