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Journal articles
Focusing on the future of paper machines, TAPPI JOURNAL, January 1998, Vol. 81(1)
Focusing on the future of paper machines, TAPPI JOURNAL, January 1998, Vol. 81(1)
Journal articles
Influence of coating composition on web release in high speed film transfer coating, TAPPI JOURNAL, January 1998, Vol. 81(1)
Influence of coating composition on web release in high speed film transfer coating, TAPPI JOURNAL, January 1998, Vol. 81(1)
Journal articles
The role of analytical winding dynamics in winder design, TAPPI JOURNAL, January 1998, Vol. 81(1)
The role of analytical winding dynamics in winder design, TAPPI JOURNAL, January 1998, Vol. 81(1)
Journal articles
Tools of the hedging trade, TAPPI JOURNAL, January 1998, Vol
Tools of the hedging trade, TAPPI JOURNAL, January 1998, Vol. 81(1)
Journal articles
89APR177
MD microstriations in paper: a two-sided shrinkage phenomenon?, TAPPI JOURNAL April 1989
Journal articles
A targeted approach to produce energy-efficient packaging materials from high-yield pulp, TAPPI Journal August 2025
ABSTRACT: Unlike fossil-based plastics, wood-based packaging materials can be produced in an ecofriendly manner using wood chip residuals from sawmills and pulpwood. To produce high-yield pulp like chemithermomechanical pulps (CTMPs) for paperboard and liquid packaging, it is crucial to reduce the electric energy consumption during fiber separation. The ultimate objective is to revolutionize paperboard production by achieving a middle-layer CTMP process that consumes less than 200 kilowatt-hours per metric ton (kWh/t), significantly improving from the current 500•600 kWh/t energy demand. Optimizing the CTMP impregnation process of sodium sulfite (Na2SO3) in wood chips is crucial for achieving uniform softening, ideally at the fiber level. The properties of the fibers are significantly affected by the content of lignin sulfonates within the walls of the fiber and the middle lamellae. In this study, we employed in-house developed X-ray fluorescence (XRF) techniques, validated by beamline measurements, to map the distribution of sulfonated lignin within fibers. It also seemed possible to enhance the surface area of lignin-rich pulp fibers while losing minimal bulk by refining them with well-optimized low consistency (LC) refining. We aimed to achieve a highly efficient separation of coniferous wood fibers by co-optimizing the sulfonation and the temperature in the preheater and chip refiner. Additionally, we explored how lignin’s softening behavior and potential crosslinking influence subsequent unit operations, including pressing, peroxide bleaching, and drying, following the defibration process. In defibration during chip refining, the maximum softening of wood fibers is preferred to maximize fiber preservation and minimize energy consumption. However, optimizing the stiffness of finished pulp fibers is preferable to reduce bulk loss during paperboard production. It can strive to optimize processes to develop stronger, lighter, and more sustainable composite packaging materials. Reducing environmental impact and electric energy can help create a more sustainable future.
Journal articles
On the design of corrugated boards: A new FEM modeling and experimental validation, TAPPI Journal August 2025
ABSTRACT: This study presents a simplified finite element modeling (FEM) approach suitable for large structures made of corrugated boards, such as customized packages, based on a homogenization method, which is combined with correction factors for internal mechanisms. The homogenization process reduces computational time by transforming flute geometries into equivalent elastic models. In large deformations and in the presence of contact for a given geometry, the effective elastic modulus in the thickness direction, as well as the effective thickness of the structure, are corrected by two statistical Weibull distributions representing the contact and buckling mechanisms in a corrugated board. The Weibull parameters are obtained via experimental analysis, and such a process is then validated. The results demonstrate that the statistical parameters (â1 = 0.14, â2 = 1.31) can be used for the simplistic representation of corrugated boards, being computationally efficient. This research contributes to the optimization of corrugated packaging design, specifically by simplifying FEM models for faster, yet equally accurate, simulations.
Journal articles
Effect of xylan on the mechanical performance of softwood kraft pulp 2D papers and 3D foams, TAPPI Journal March 2025
ABSTRACT: Pulp fibers are paramount in paper products and have lately seen emerging use in fiber foams. Xylan, an integral component in pulp fibers, is known to contribute to paper strength, but its effect on the strength of pulp fiber foams remains less explored. In this study, we investigate the role of xylan in both 2D handsheets and 3D foams. For a softwood kraft pulp, we enzymatically removed 1% from pulp fibers and added 3% xylan to them by adsorption, corresponding to approximately a decrease of a tenth and an increase of a third of the total xylan content. The mechanical properties of 2D fiber networks, i.e., handsheets, made using the xylan-enriched pulp improved, particularly regarding tensile strength and Young’s modulus; however, the decrease in mechanical properties of handsheets made from enzymatically- treated xylan-depleted pulp was more pronounced. In 3D networks • pulp fiber foams, much less fiber-fiber contacts formed, and thus the mechanical properties were not as much influenced by removal of xylan. Furthermore, the presence of the required surfactant on the fibers, acting as debonding agent, overshadows any positive effect xylan might have on fiber-fiber bonding. We propose that the improved mechanical properties for the sheets result from a combination of an increased number of fiber-fiber bonds and higher sheet density, while the deterioration in mechanical properties of handsheets comprising enzymatically-treated fibers is caused by the opposite effect.
Journal articles
Predictive advisory solutions for chemistry management, control, and optimization, TAPPI Journal March 2025
ABSTRACT: Process runnability and end-product quality in paper and board making are often connected to chemistry. Typically, monitoring of the chemistry status is based on a few laboratory measurements and a limited number of online specific chemistry-related measurements. Therefore, mill personnel do not have real-time transparency of the chemistry related phenomena, which can cause production instability, including deposition, higher chemical consumption, quality issues in the end-product and runnability problems. Machine learning techniques have been used to establish soft sensor models and to detect abnormalities. Furthermore, these soft sensors prove to be most useful when combined with expert-driven interpretation. This study is aimed at utilizing a hybrid solution comprising chemistry and physics models and machine learning models for stabilizing chemistry-related processes in paper and board production. The principal idea is to combine chemistry/physics models and machine learning models in a fashion close to white box modeling. A cornerstone in the approach is to formulate explanations of the findings from the models; that is, to explain in plain text what the findings mean and how operational changes can mitigate the identified risks. The approach has been demonstrated for several different applications, including deposit control in the wet end, both raw water treatment and usage, and wastewater treatment. This approach provides mill personnel with knowledge of identified phenomena and recommendations on how to stabilize chemistry-related processes. Instead of using close to black box machine learning models, a hybrid solution including chemistry/physics models can enhance the performance of artificial intelligence (AI) deployed systems. A successful way of gaining the trust from mill personnel is by creating a plain text explanation of the findings from the hybrid models. The correlation between the likelihood of a phenomena and disturbance and the explanations are derived and validated by application and chemistry and physics experts.
Journal articles
Colloidal silica and its effects during formation of paper sheets in the presence of nanofibrillated cellulose, cationic starch, and cationic acrylamide copolymer, TAPPI Journal May 2025
ABSTRACT: This work considered effects of colloidal silica addition during laboratory preparation of paper sheets containing nanofibrillated cellulose (NFC) that had been pretreated with cationic starch. The emphasis was on process performance issues, including dewatering rates, fine particle retention, and the extent of fiber flocculation. In addition, micrographs were obtained to show what was happening to the NFC upon treatments with cationic starch and subsequent application of hydrodynamic shear. Contrasting results were obtained, depending on the charge density of the cationic starch. Pretreatment of the NFC with a high charge density cationic starch (degree of substitution 0.2) resulted in strong interactions with the colloidal silica, enhancing the dewatering rate and contributing to fine-particle retention. The medium charge cationic starch pretreatment led to effects suggesting a bridging mechanism of action, and subsequent colloidal silica had no significant effect on dewatering. Treatment of that system with a high level of colloidal silica (0.2%) resulted in lower retention. In general, the final colloidal silica treatments tended to decrease the level of flocculation in the suspensions, giving more uniform handsheets. Mechanisms, some of them related to the clustering and dispersion of cationic starch-treated NFC, were proposed to account for the observed effects.