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Summary: The impact of a five months water storage together with a bacterial treatment, on the mechanical properties of spruce is analysed by ultrasonic waves. The Bacillus subtilis is used to improve the permeability of spruce sapwood. The attack of bacteria on the torus of aspirated pits is expected to lead to a better transport of preservative liquids. The elastic constants were calculated through ultrasonic velocities which were measured at different types of specimens. The results were compared with the constant EL as determined by a static bending test. The calculated loss of strength seems to be negligible but variations in the elastic properties of anatomical plaines consisting radial axes, can be well predicted.

Abstract: Decontamination of synthetic acetate, chloride, nitrate, and sulfate solutions containing 10, 100, 1,000, 10,000, and 50,000 ppm of copper using chemically treated barks has been studied. Metal percentage removal from solutions depends on the pH, the initial concentration, and, to some extent, the anion. It varies from 40 through 99 pct of the initial metallic ion’s content in the solution. The average retention capacity of the treated bark is about 43 mg of Cu/g of dry modified bark (0.68 mmole/g of dry bark). Extraction of copper cations from the saturated modified bark was made possible with dilute acid. Regeneration of bark for reuse as an ion exchanger was possible. Bark loaded with copper was analyzed by scanning electron microscopy (SEM) and infrared (IR) spectroscopy. Copper was uniformly distributed in the bulk of the bark. No copper segregation was observed. It seems that copper was bound to the acidic (phenolic) sites of the bark. Anions were not detected on the copper-loaded bark with either SEM electron probe microanalysis or IR spectroscopy. Incineration of the bark loaded with copper resulted in ashes containing about 77 pct of copper oxides, while pyrolysis of the same sample led to ashes containing 10 pct of metallic copper and about 85 pct carbon.