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Journal articles
Assessing lignin content in Nordic hardwood and softwood species using models based on near-infrared (NIR) spectral data and partial least squares regression (PLSR), TAPPI Journal September 2025
ABSTRACT: Continuous kraft cooking digesters face challenges affecting product quality, making it valuable to improve control through advanced techniques like near-infrared (NIR) spectroscopy, model predictive control, and machine learning models. The primary goal of this study was to use NIR spectra to predict the amount of lignin in hardwood and softwood samples. This study investigated the correlation of NIR derivative spectra with the amounts of lignin relative to other constituents, namely cellulose, hemicellulose, and water, in wood chip samples of varying chip sizes and shapes from six Nordic wood species. It employed partial least squares regression (PLSR) on the NIR data to construct a model that predicted the lignin fraction and the relative fraction of acid-soluble lignin. When trained on a group of five wood species, the model achieved a satisfactory predictive ability, striking a balance between a wide range of lignin content and a consistent chemical environment. The accuracy increased further when the model was restricted only to spruce and pine, reflecting the benefits of a more homogenous dataset. Additionally, the optimal number of latent variables was identified as two, indicating that three distinct chemical components — cellulose, lignin and water — can be effectively differentiated using NIR.
Journal articles
Release of nitrogen species from the recovery processes of three kraft pulp mills, Solutions! & TAPPI JOURNAL, October 2004, Vol. 3(10) (326KB)
Release of nitrogen species from the recovery processes of three kraft pulp mills, Solutions! & TAPPI JOURNAL, October 2004, Vol. 3(10) (326KB)
Journal articles
Mechanistic aspects of microparticle systems, TAPPI JOURNAL, November 2005, Vol. 4(11) (168 KB)
Mechanistic aspects of microparticle systems, TAPPI JOURNAL, November 2005, Vol. 4(11) (168 KB)
Journal articles
Inorganic scale buildup in a bleach plant a mill case study, TAPPI JOURNAL, November 2005, Vol. 4(11) (168 KB)
Inorganic scale buildup in a bleach plant a mill case study, TAPPI JOURAL, November 2005, Vol. 4(11) (168 KB)
Journal articles
Insights on the refining mechanism, TAPPI JOURNAL, March 2002, Vol. 1(1) (346KB)
Insights on the refining mechanism, TAPPI JOURNAL, March 2002, Vol. 1(1) (346KB)
Journal articles
Influence of pulping conditions on eucalyptus kraft pulp yield, quality, and bleachability, TAPPI JOURNAL, March 2002 (191KB)
Influence of pulping conditions on eucalyptus kraft pulp yield, quality, and bleachability, SOLUTIONS! & TAPPI JOURNAL, March 2002 (191KB)
Journal articles
Adsorption of sodium on O2-prebleached Eucalyptus globulus kraft pulp, TAPPI JOURNAL, March 2002, Vol. 1(1) (110KB)
Adsorption of sodium on O2-prebleached Eucalyptus globulus kraft pulp, TAPPI JOURNAL, March 2002, Vol. 1(1) (110KB)
Journal articles
Papermaking potential of congress grass: pulpability and fiber characteristics, TAPPI JOURNAL, March 2002, Vol. 1(1) (147KB)
Papermaking potential of congress grass: pulpability and fiber characteristics, TAPPI JOURNAL, March 2002, Vol. 1(1) (147KB)
Journal articles
Where to add retention aid: issues of time and shear, TAPPI JOURNAL, March 2002 (174KB)
Where to add retention aid: issues of time and shear, SOLUTIONS & TAPPI JOURNAL, March 2002 (174KB)
Journal articles
Visualizations of offset and flexographic inks at bubble surfaces, TAPPI JOURNAL, March 2002 (251KB)
Visualizations of offset and flexographic inks at bubble surfaces, SOLUTIONS & TAPPI JOURNAL, March 2002 (251KB)