Resumen de Estimating density and pulping yield of e. Globulus wood: Comparison of near-infrared (nir) and mid-infrared (mir)

José Ruiz, Jaime Rodríguez, Jaime Baeza, Juanita Freer

• The application of near-infrared (NIR) spectroscopy as a tool for the rapid determination of pulp yield and basic density of Eucalyptus globulus wood is described. Previously, we had examined these properties using mid-infrared (MIR) spectroscopy. More precise results were obtained based on NIR spectra where the calibrations models were more robust and better predictors than obtained for the MIR spectra. Twenty-seven samples were used for establishing the correlations (calibration) and three for making predictions based on the calibration (validation). Quant+ chemometrics software was used to obtain the calibration and prediction through principal components regression (PCR). A PCR model based on NIR spectra gave fits with a standard error of prediction (SEP) of 14.3 kg m-3 and 1.57% for basic density and pulping yield, respectively. Using PCR-MIR, the SEP values obtained were 21.44 kg m-3 and 1.73%. The method readily predicts yield (correlation coefficient: R²= 0.51), and density (correlation coefficient: R² = 0.94) from spectral NIR measurement. Both NIR and MIR performed better in the analysis of the density property than for the pulp yield of the hardwood samples