Understanding of surface roughness of wood based on analysis its structure and density

Understanding of surface roughness of wood based on analysis its structure and density. The main aim of presented paper was to investigate the influence the wood density and anatomical details on surface roughness. The scope of study included samples from ten different species of wood (mainly tropical) because of wide range of density and anatomical difference. The results allow to conclude that the roughness of tested wood species demonstrated variation, depending on the wood section and the measurement direction. In general, radial sections showed higher roughness than tangential sections due to interlocked fibres in tested wood species (fibres cut in various ways on the radial section of the wood). Roughness measured perpendicular to the wood fibres were twice as high as those measured parallel to the grain. Wood density was not an important indicator determining surface roughness for tested wood species. The determining element for the roughness measured across the fibres was the diameter of the vessels. Further research is advisable due to the enormous variability of the structure and properties of wood.

Insight of Weathering Processes Based on Monitoring Surface Characteristic of Tropical Wood Species

The main aim of the presented research was to compare the influence of selected ageing factors, such as UV radiation and complex artificial weathering methods, on the colour, wettability and roughness changes in garapa, tatajuba, courbaril and massaranduba from South America—tropical wood species that are popular for external usage in European countries. Both processes caused wood surfaces to become darker and turn to shades of brown. The highest total colour changes were shown in courbaril wood (wood with the highest extractives content). The wood surface roughness demonstrated variation, depending on the wood section and measurement direction, and increased after ageing treatments. Changes in surface contact angle were significant after the inclusion of water and drying in the weathering process (wettability decreased). Anatomical analyses of the tested tropical woods revealed structural changes after used artificial weathering treatments (distortion between cell elements, degradation of the middle lamella, micro-cracks in cell walls, thinning and degradation of parenchyma cells, cracks along pits within vessels). As a result of desorption tension, the changes caused by UV irradiation were much smaller than those caused by full artificial weathering. Fourier-transform infrared spectroscopy (FTIR) analysis indicated the occurrence of lignin and hemicelluloses oxidative changes after the weathering process which resulted in the formation of carbonyl and carboxyl compounds. The depolymerisation of cellulose was also identified. The results show that the observed changes may affect the long-term durability of finishes applied over wood subjected to weathering factors for a short period before finishing.

“The Ground Necessary”

In order to examine the spatial layout and organization of the encampment at Valley Forge, this chapter describes the results of a sampling from an archaeological transect through its Wayne’s Woods section. The transect started from a forward-moving area at the outskirts and continued along a defensive entrenchment, moving through soldiers’ huts, officers’ huts, and, finally, through the camp kitchens and sutlers’ area, which were the more centrally located sections of the camp. The research provided information about the status differences between soldiers and officers, including their diets, defensive entrenchments and earthworks, and routines and activities. It also demonstrated that organization of the Wayne’s Wood section followed the general outline of von Steuben’s orders.

A Comparison Between Ladell's Wood Section Method and the Macerated Wood Method for Tracheid Length Determination

A comparison has been made between the method of Ladell, in which tangential longitudinal sections are used for the determination of mean tracheid length and the traditional method using macerated wood. The two methods produced identical results. Ladell's method was quicker, enabled precise location of measured cells and required less sample preparation.