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
Author
Todorović, NebojšaMentor
Popović, ZdravkoCommittee members
Zdravković, VladislavMilić, Goran

Džinčić, Igor
Jović, Branislav
Metadata
Show full item recordAbstract
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.