Mechanical parameters of ash wood (Fraxinus excelsior) subjected to compression in radial direction, before and after its thermal modification and measured at moisture content close to the equilibrium moisture content of wood exposed in and outside (4 and 12%) were compared. Thermal modification of wood was performed at 190°C or 200°C for 2 h in industrial conditions. During the measurements, the moisture content of the modified and control samples was identical. The parameters compared included: modulus of elasticity, stress at proportionality limit, relative linear strain at proportionality limit and accumulated elastic energy. Changes in the mechanical parameters of wood induced by its thermal modification were found to depend on the modification temperature and wood moisture content.

Variation in MechanicalProperties within Individual Annual Rings of the Resonance Spruce Wood ¢Picea abies (L.) Karst.£ Varijacije mehaničkih svojstava unutar pojedinih godova rezonantne smrekovineOriginal scientifi c paper • Izvorni znanstveni rad Received -prispjelo: 11. 7. 2013. Accepted -prihvaćeno: 23. 6. 2014 630*.811.4; 674.032.475.542 doi:10.5552/drind.2014

Mechanical parameters of ash wood (Fraxinus excelsior) subjected to compression in tangential direction, before and after its thermal modification and measured at the moisture content close to the equilibrium moisture content of wood used inside and outside the house, (4 and 12%) were compared. Thermal modification of wood was performed at 190°C and 200°C for 2 hours in industrial conditions. During the measurements, the moisture content of the modified and control samples was the same. The parameters compared included: modulus of elasticity, stress at proportionality limit, relative linear strain at proportionality limit and accumulated elastic energy. Thermal modification of ash wood at 190°C contributed to the deterioration of its mechanical parameters determined during compression in tangential direction; the deterioration was greater for wood tissue of higher moisture content. The values of mechanical parameters of thermally modified wood (except for elastic energy), determined in compression test in tangential direction, decrease with the its increasing moisture more than for the control wood.

The objective of the study was to investigate the inuence of wood species on sound timbre generated by electric string instruments. The obtained results allow to conclude that wood species have the largest inuence on the specic sound loudness and it correlates with density and modulus of elasticity. The greater dierences occur at lower frequencies. There was no correlation between signal recorded by microphone and pickup.