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Chemical Primers for Extrusion Coating and Extrusion Lamination, 1993 International European Extrusion Coating Symposium Proceedings

Chemical Primers for Extrusion Coating and Extrusion Lamination, 1993 International European Extrusion Coating Symposium Proceedings

Automatic Gauging for Improved Quality, 1993 International European Extrusion Coating Symposium Proceedings

Automatic Gauging for Improved Quality, 1993 International European Extrusion Coating Symposium Proceedings

Experimental and Theoretical Investigations for Metering Size Press, 1999 Coating Fundamentals Symposium Proceedings

Experimental and Theoretical Investigations for Metering Size Press, 1999 Coating Fundamentals Symposium Proceedings

Characterization of Surface Topography of Coated Paper, 1999 Coating Fundamentals Symposium Proceedings

Characterization of Surface Topography of Coated Paper, 1999 Coating Fundamentals Symposium Proceedings

Application of Atomic Force Microscopy in Pigment and Dispersion Coating Analysis, 1999 Coating Fundamentals Symposium Proceedings

Application of Atomic Force Microscopy in Pigment and Dispersion Coating Analysis, 1999 Coating Fundamentals Symposium Proceedings

Influence of Dynamic Rheological Behavior on Final Coating Properties: Part 2- Dynamic Suspension Rheology and Coating Structure Consolidation, 1999 Coating Fundamentals Symposium Proceedings

Influence of Dynamic Rheological Behavior on Final Coating Properties: Part 2- Dynamic Suspension Rheology and Coating Structure Consolidation, 1999 Coating Fundamentals Symposium Proceedings

Rheological Aspects of Misting Mechanisms in Roll Applied, Non-Newtonian Paper Coatings and Inks, 1999 Coating Fundamentals Symposium Proceedings

Rheological Aspects of Misting Mechanisms in Roll Applied, Non-Newtonian Paper Coatings and Inks, 1999 Coating Fundamentals Symposium Proceedings

Industrial Monitors Tailored to High Moisture Pulp and Paper Mill Environments, Paper360º November/December 2025

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.

Textiles: A New Door of Opportunity Opens, Paper360º November/December 2022