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This paper presents the results of granulometric analyses of sawdust of unmodified and thermally- modified ash wood (Fraxinus exelsior L.) sawed on a narrow-kerf sash gang saw. The sawdust of dry thermally-modified ash produced in the sawing process on a frame sawing machine PRW15-M at a feed speed in the range of 0.36-1.67 m·min-1 has chip granularity ranging from 33.5 μm to 9.9 mm; whereas unmodified ash wood sawdust consists of chips in a granularity range from 35.6 μm to 13.8 mm. It was observed that thermally-modified ash sawdust is finer, with a distinctly larger share of the fraction in the granularity range a = 125-500 μm and a slightly increased share of the fraction in the range a = 32-125 μm. Changes in mechanical characteristics of modified wood were also observed in the technological usefulness of a part of dry sawdust chip in the granularity range a = 250 μm-2.4 mm. While the homogenous share of chips in sawdust produced in the process of sawing of dry ash wood was HSCha = 81-84 %, the demonstrated homogenous share of chips in ash sawdust formed in the process of sawing of dry thermally-modified wood was lower by 4-6 %.
Calculation of the specific heatcapacityof frozen wood during its defrosting in hygroscopic diapason. An approach for the calculation of the specific heat capacity c of frozen wood with ice in it, which is created from the freezing of hygroscopically bounded water, has been suggested. The approach takes into account the physics of the process of towing of this ice in the wood. It reflects for the first time the influence of the fiber saturation point ufsp of the separate wood species on the specific heat capacity of frozen wood c during wood defrosting in hygroscopic diapason and also the influence of the temperature on the ufsp and c. For the calculation of c according to the suggested approach a software program has been prepared, which has been input in the developed by Microsoft calculation environment of Visual Fortran Professional. With the help of the program computations have been made for the determination of c during towing of the mentioned above ice in oak wood with moisture content 0 ≤ u ≤ ufsp at the temperature range between -60oC and -0oC.
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