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Primena bliske infracrvene spektroskopije u predviđanju svojstava termički modifikovanog drveta bukve sa lažnom srčevinom

Application of near-infrared spectroscopy in prediction of properties of thermally modified beech wood with red heartwood

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2012
Nebojsa_Todorovic.pdf (13.21Mb)
Author
Todorović, Nebojša
Mentor
Popović, Zdravko
Committee members
Zdravković, Vladislav
Milić, Goran
Džinčić, Igor
Jović, Branislav
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Abstract
Bukva je najvažnija vrsta drveta na Balkanskom poluostrvu i posebno je interesantna zbog potencijalnog prisustva lažne srčevine. Imajući u vidu značaj termičke modifikacije i nedestruktivnog ispitivanja drveta, predmet doktorske disertacije je bio istraživanje primene bliske infracrvene spektroskopije (NIR) u predviđanju osnovnih fizičkih (gustina i boja) i savojnih (čvrstoća na savijanje - MOR i modul elastičnosti - MOE) svojstava termički modifikovanog drveta bukve sa lažnom srčevinom. Uzorci su termički modifikovani na temperaturama od 170º C, 190º C i 210º C u trajanju od 4h. NIR spektri (sa rezolucijom od 100 skenova i 4 cm-1) su snimljeni pre i posle termičkog tretmana pri čemu je sa poprečne površine snimljeno četiri, a sa radijalne osam spektara. Predviđanje svojstava je urađeno korišćenjem multivarijacione metode parcijalnih najmanjih kvadrata (PLS) pri čemu je utvrđena regresiona zavisnost između ispitanih svojstava i prosečnih NIR spektara. Kalibracioni modeli su izrađeni po...moću metode unakrsne validacije. Pored primene NIR spektroskopa, u radu je istraživana i mogućnost predviđanja navedenih svojstava pomoću PLS analize sa 12 koordinata boje. U radu je pokazano da primenjena temperatura smanjuje vrednosti svojstava beljike i lažne srčevine i izjednačuje njihovu boju. Pored zadovoljavajućih rezultata u predviđanju svojstava netretiranog drveta, dobijeni su korisni rezultati koji pokazuju i mogućnost primene NIR-a u proceni kvaliteta termički modifikovanog drveta. Generalno, nijedna površina se nije istakla po svojim rezultatima, dok su kod beljike zabeleženi bolji rezultati u odnosu na lažnu srčevinu. Najveća vrednost koeficijenta determinacije (R2) kod termički modifikovane beljike je zabeležena u proceni promene boje (R2=0,95) i MOR (R2=0,85), dok je kod termički modifikovane lažne srčevine najveća vrednost utvrđena, takođe, kod promene boje (R2=0,96) i MOE (R2= 0,79). Ono što je naročito interesantno, za nauku i praksu, jesu rezultati koji pokazuju da se svojstva termički modifikovane bukovine mogu predvideti i pomoću NIR spektara snimljenih pre tretmana. Zabeleženo je da se boja, kao nedestruktivna tehnika, pokazala kao slabiji pokazatelj za većinu ispitanih svojstava od NIR spektroskopa.

Beech is the most significant wood species on Balkan Peninsula and it is especially interesting due to potential presence of red heartwood. Considering the significance of thermal modification and of the non-destructive examination of timber, the object of doctoral dissertation was examination of application of near-infrared spectroscopy (NIR) in prediction of basic physical (density and color) and bending (bending strength – MOR and modulus of elasticity – MOE) properties of thermally modified beech wood with red heartwood. Samples were being thermally modified at temperatures of 170°C, 190°C and 210°C during 4h. NIR spectra (with a resolution of 100 scans and 4 cm-1) were recorded before and after thermal treatment, with four spectra recorded from cross-section surface and eight spectra recorded from radial surface. Prediction of properties was done by using the multivariate partial least squares regression (PLS) which determined the regressive correlation between the properties exam...ined and the average NIR spectra. Calibration models were made by using the cross-validation method. Along with the use of spectroscope, the possibilities of prediction of properties using the PLS analysis with 12 color coordinates were also examined. Thesis indicates that the applied temperature reduces the values of properties in sapwood and red heartwood and that it equalizes their colors. Along with satisfying results in prediction of properties of untreated wood, useful results which indicate the possibility of application of NIR in assessment of quality of thermally modified wood were produced. In general, none of the surfaces produced prominent results, while sapwood produced better results compared to red heartwood. The greatest coefficient of determination (R2) in thermally modified sapwood was recorded in assessments of color change (R2=0,95) and of MOR (R2=0,85), whereas greatest values in thermally modified red heartwood were produced in assessments of color change (R2=0,96) and of MOE (R2=0,79). Especially interesting results for the science and practice are those that indicate that the properties of thermally modified beech wood can be predicted by recording the NIR spectra before the treatment. However, for most of the properties examined, color assessment, as a non-destructive technique, proved to be a weaker indicator than NIR spectroscopy.

Faculty:
Универзитет у Београду, Шумарски факултет
Date:
29-11-2012
Projects:
  • Sustainable management of the total forest potential in the Republic os Serbia (RS-37008)
Keywords:
Bukva / Beech / red heartwood / thermal modification / near-infrared spectroscopy / PLS analysis / lažna srčevina / termička modifikacija / bliska infracrvena spektroskopija / PLS analiza
[ Google Scholar ]
Handle
https://hdl.handle.net/21.15107/rcub_nardus_3512
URI
http://eteze.bg.ac.rs/application/showtheses?thesesId=341
https://nardus.mpn.gov.rs/handle/123456789/3512
https://fedorakg.kg.ac.rs/fedora/get/o:5978/bdef:Content/download
http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=512533916

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