Properties and use of biomass from reclaimed land in the North Bohemian Basin

Spoil heaps are negative urban landscape features resulting from intense human activities to acquire mineral resources. One very positive method for reclaiming spoil heaps is afforestation. This paper analyzes the quality of Black locust wood acquired from the reclaimed area of Varvažov, North Bohemian Basin, Czech Republic. The following characteristics were used as indicators of the quality of wood obtained from the given area: chip dimensions; ash content; bulk density; bark content; contents of C, H, N, and O; and contents of S, P, Ca, Mg, K, Fe, Zn, and Mn. Black locust biomass is suitable for energy purpose, although it contains an increased proportion of inorganic elements. The other properties, such content of C, H, N, and O, ash content as well as heating value, are in compliance with the standardized values. The Black locust chips can be categorized as Coarse-grained energetic wood chips with minimal dust particle content according to particle-size distribution analysis.

Dependence of roughness change and crack formation on parameters of wood surface embossing

This paper deals with roughness change and crack formation after surface embossing of aspen wood. Embossing was carried out with three various shapes of embossing wedges (convex, concave and with 45° angle). The embossing was realized with two temperatures, 20 and 160°C. The surface roughness before and after embossing was evaluated on the basis of the arithmetical mean deviation of the roughness profile, Ra. Surface quality measurements were carried out in perpendicular (transversal) and parallel (longitudinal) direction in relation to wood fibers. Embossment area quality was evaluated by the mean of portion of cracks in embossment. This evaluation was based on digital image of embossed area and subsequently calculation of portion of cracks area in relation to total evaluated area. Elevated temperature has a positive effect on the quality of the surface, because of roughness decrease. However, the increase in temperature causes a growth in the proportion of cracks on the embossed surface.