Proceedings e report - Firenze University Press

WOOD SCIENCE FOR CONSERVATION OF CULTURAL HERITAGE
Fig. 5 depicts the score plots derived from PLS analysis for Model-I. Numbers in the figure indicates
tht. t1 shows gradual decrease with tht. Decreasing of t2 explains the decreasing of amorphous region, or
increasing of crystallinity.
Loading coefficient
Loading coefficient
0.05
(a)
-0.05
1st component (p1) -0.1
0.10
(b)
0.05
0
0
-0.05 2nd component (p2) 10000 8000 6000
Wavenumber(cm-1 )
Fig. 4. Loading plots of PLS components of hinoki
cypress: (a) 1st component (b) 2nd component
5. Conclusion
4000
195
2nd component score (p 2)
0.5
0
100
100
50
50
10
20
20 10
-0.5
-3 -2 -1 0 1
1st component score (p1) Fig. 5. Score plots derived from PLS analysis of
hinoki cypress.
In this study, degradation mechanism of hydrothermally treated hinoki cypress and beech were
investigated in conjunction with NIR spectroscopy and PLS regression analysis where the sample was
regarded as an analogue of archaeological objects. Two PLS regression models were developed for the
determination of compressive Young’s modulus of hydrothermally treated wood. The prediction gave
strong relationships between measured and predicted value both in Model-I and Model-II. It was
suggested that the variation of compressive Young’s modulus with hydrothermal treatment was
governed by two main processes, that is, the depolymerization of polysaccharide and the variation of
the cellulose crystallinity both in hinoki wood and beech wood.
It was concluded that the NIR spectroscopy with aid of chemometrics is useful to understand the
degradation mechanism of archaeological hardwood taking into consideration its molecular structure
and interaction between wood properties and mechanical properties.
Acknowledgement
This study was partly supported by Grant-in-Aid for Scientific Research from the Japan Society for
the Promotion of Science (grant numbers 19380099 to ST and 20007231 to TI).
References
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2. E. Franceschi, J. Cascone and D. J. Nole (2008): Study of artificially degraded woods simulating
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4. H. Yonenobu and S. Tsuchikawa (2003): Near-Infrared Spectroscopic Comparison of Antique
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5. K. Kramer: (1998), “Chemometric Techniques for Quantitative Analysis”. Marcel Dekker, New
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