Proceedings e report - Firenze University Press

DIMENSIONAL CHANGE OF UNRESTRICTED WOOD AT DIFFERENT LEVELS OF EQUILIBRIUM MOISTURE CONTENT
Line drawings using AutoCAD were made when the samples were at 0% MC and at room
temperature. Drawings were drawn using a scale of 10:1, for higher accuracy. All dimensions and
grain orientations were measured and introduced into the Microsoft Excel spreadsheet.
The following two predictions were done:
(i) Case 1: calculations based on literature data of Pinus eliotta (Slash pine). [8]
(ii) Case 2: calculations based on experimental results.
Table 2 shows the data used for these tests.
Table 2: Data used for pine computer program
DATA USED FOR PINE SAMPLE
TEST
INITIAL
TEMP.ºC
INITIAL
RH %
FINAL
TEMP.ºC
FINAL
RH%
PUBLISHED DATA FOR
TAN% RAD% LONG% FSP%
CASE 1
CASE 2
17.0 0.0 15.1 100.0
7.6
7.91
5.4
3.73
0.1
0.31
30.0
Fig. 3 shows the final drawings, where the resulting diagrams for both Case 1 and Case 2 were
superimposed onto the true scanned images of the pine sample.
Fig. 3 – Results of computer analysis carried out on the pine sample
5.3.2. Test Limitations
The samples were too small and therefore the margin of error in measurement results to be larger.
There must have been greater error with the thickness measurements (c.11mm) when compared with
those for the length (c.78mm) and the width (c.89mm).
5.4. Presentation and analysis of the computer procedure
As can be seen from Fig. 3, the computer procedure is quite accurate. Although slightly different from
published values, experimental results were not very significant considering the sample was quite
small, and subjected to extreme conditions (from 0 to 31% MC). As expected, due to the difference
between experimental and literature data (7.91-7.60% tangential value higher by 0.31%) the
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