Using NIR and ATR-FTIR spectroscopy to rapidly detect compression wood in Pinus radiata (original) (raw)
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Canadian Journal of Forest Research, 2011
The predictions of properties for wood disc average are seldom reported, and they are important for sorting out logs based on their quality. The minimum near infrared (NIR) spectra required to predict wood disc average properties would also be of critical importance. In this study, calibration and prediction models for wood disc average properties were developed using NIR spectral data for balsam fir (Abies balsamea (L.) Mill.) and black spruce (Picea mariana (Mill.) B.S.P.) samples collected from 14 different sites across Newfoundland, Canada. The calibration was done against area-weighted average wood properties determined by SilviScan. NIR spectra were collected in 18 mm increments from the radial-longitudinal face of green and oven-dried samples. Results showed that using NIR spectra from three spots per wood strip was sufficient for the modeling and prediction for density and module of elasticity (MOE). The coefficients of determination ranged from 0.76 (MOE of green wood samples) to 0.88 (density of oven-dried wood samples). However, the microfibril angle (MFA) cannot be well predicted from either green wood or oven-dried wood NIR spectra. Our results further showed that the NIR spectra collected from oven-dried wood samples gave better calibration and prediction than those collected from green wood samples.
Prediction of loblolly pine wood properties using transmittance near-infrared spectroscopy
Canadian Journal of Forest Research, 2005
Near-infrared (NIR) spectroscopy is a rapid nondestructive technique that has been used to characterize chemical and physical properties of a wide range of materials. In this study, transmittance NIR spectra from thin wood wafers cut from increment cores were used to develop calibration models for the estimation of α-cellulose content, average fiber length, fiber coarseness, and lignin content in the laboratory. Eleven-year-old trees from two sites were sampled using 12-mm increment cores. Earlywood and latewood of ring 3 and ring 8 from these samples were analyzed in the laboratory using microanalytical methods for α-cellulose content, average fiber length, fiber coarseness, and lignin content. NIR calibrations and laboratory measurements based on one site were generally reliable, with coefficients of determination (R 2 ) ranging from 0.54 to 0.88 for average fiber length and α-cellulose content, respectively. Predicting ring 8 properties using ring 3 calibration equations showed potential for predicting α-cellulose content and fiber coarseness, with R 2 values of approximately 0.60, indicating the potential for early selection. Predicting the wood properties using the calibration equations from one site to predict another showed moderate success for α-cellulose content (R 2 = 0.64) and fiber coarseness (R 2 = 0.63), but predictions for fiber length were relatively poor (R 2 = 0.43). Prediction of lignin content using transmittance NIR spectroscopy was not as reliable in this study, partially because of low variation in lignin content in these wood samples and large errors in measuring lignin content in the laboratory.
Carbohydrate Polymers, 2010
Fourier transform infrared (FTIR) spectroscopy, in combination with multivariate analysis, enable the analysis of wood samples without time-consuming sample preparation. The aim of our work was to analysis the wood samples qualitatively and quantitatively by FTIR spectroscopy. A Van Soest method to determine the lignin, cellulose and hemicellulose content, was used as reference method. Multivariate calibration was performed based on first derivative of the FTIR spectra in the wave number range from 1900 to 800 cm −1 , using principal component analysis (PCA), hierarchical cluster analysis (HCA) and partial least-squares (PLS) chemometric methods. Multivariate calibration models for FTIR spectroscopy have been developed. Using PCA and HCA approach, wood samples were classified as softwoods and hardwoods while wood samples with and without treatments were labeled as wood, neutral detergent solution fiber (NDSF), acid detergent solution fiber (ADSF) and strong acid solution fiber (SASF). Furthermore, PLS regression method was applied to correlate lignin, cellulose and hemicellulose contents in wood samples with the FTIR spectral data. The models' refinement procedure and validation was performed by cross-validation. Although a wide range of input parameters (i.e., various wood species) was used, highly satisfactory results were obtained with the root-mean-square errors for the contents of lignin, cellulose and hemicellulose are 1.51, 0.96 and 0.62%, respectively. This study showed that FTIR spectra have the potential to be an important source of information for a quick evaluation of the chemical composition of wood samples.
CERNE, 2010
Mechanical properties studies of wood usually involve destructive wood assessments, with time-consuming tests that use large amounts of resource (wood). Although this is not a limiting factor, it could be attenuated by the use of a nondestructive technique known as near infrared spectroscopy (NIRS). This technique has been applied to evaluate compounds containing C-H, N-H, S-H or O-H bonds, and involves quick analyses and can be applied to process control tasks. The objective of this work is to use the NIRS technique to obtain calibrations for mechanical properties of Eucalyptus sp. wood. A natural E. urophylla hybrid at age 7 was used as obtained from V&M Florestal crops. Spectra were measured directly in solid wood (radial, tangential and transverse faces) and in ground wood, in diffuse reflectance mode, using a Bruker spectrometer in the 800 to 1,500 nm range. The NIRS technique proved suitable to estimate modulus of elasticity in solid wood, with values r=0.91 and RPD=2.6, and in ground wood, with values r=0.87 and RPD=2.0. Modulus of rupture and compressive strength presented r values below 0.9. First and second derivative pretreatments provided a slight increase in correlation values for the properties in question. Calibrations for different plank faces did not present a defined variation pattern. Solid wood and ground wood presented similar correlation values for all properties.
Journal of Near Infrared Spectroscopy, 2001
Near infrared (NIR) spectra taken from solid European larch wood samples subjected to axial bending and compression tests revealed an excellent ability to model the variability of mechanical properties using NIR spectroscopy. By including compression wood specimens, whose strength and elasticity is overestimated when modelled by density, in the investigated sample it could be demonstrated that the model is not just based on the measurement of density, but on density, surface geometry and possibly lignin content and composition. It is concluded that NIR spectroscopy shows considerable potential to become a tool for the non-destructive evaluation of small clear wood specimens, e.g. increment cores.