PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 9, Number 3, 2023
formation of the tissue paper sheet itself and its converting into different finished products. Converting is characterized by several operations, namely: unwinding, winding, embossing, lamination, perforation, cutting, packaging, and palletizing. The most impacting operation is the embossing, which consists of marking a pattern on the paper sheet by applying pressure, with the intent to produce papers more aesthetically pleasing to the final consumer and/or a way to identify a particular brand. Also, it affects final properties, increasing the liquid absorption capacity and bulk but reducing softness and tensile strength. Converting is complex and has a huge impact on the finished products properties. In this review, the authors explored the different steps of converting and how they impact the different properties of finished tissue products. Environmental Life Cycle Assessment of Premium and Ultra Hygiene Tissue Products in the United States, Amelys Brito, Antonio Suarez, Alonzo Pifano, Lee Reisinger, Jeff Wright, Daniel Saloni, Stephen Kelley, Ronalds Gonzalez, Richard Venditti & Hasan Jameel, BioResources , Vol. 18(2), 4006-4031 (2023). Under the controversial concern of using virgin fibers in hygiene tissue products, mostly Bleached Eucalyptus Kraft (BEK) and Northern Bleached Softwood Kraft (NBSK), consumers are responding by purchasing selflabeled sustainable products. As of today, there are no established sustainability reported results to inform consumers about the carbon footprint of hygiene tissue. To fill this gap, this study used Life Cycle Assessment to evaluate the environmental impacts across the supply chain (cradle to gate) to produce Premium and Ultra grades of bath tissue, including the production of feedstock, pulp production, and tissue production stages, with focus on Global Warming Potential (GWP). The results showed that one air-dried metric ton (ADmt) of BEK pulp had an associated GWP of 388 kgCO2eq, whereas one ADmt of NBSK pulp presented values ranging between 448 and 596 kgCO2eq, depending on the emissions allocation methodology used. It was estimated that the GWP of one finished metric ton of tissue weighted average could range from 1,392 to 3,075 kgCO2eq depending on mill location, electricity source, and machine technology. These results provide an understanding of the factors affecting the environmental impact of hygiene tissue products, which could guide manufacturers and consumers on decisions that impact their carbon footprint. Robust optimization and data-driven modeling of tissue paper packing considering cargo deformation, João P.L. Coutinho, Marco S. Reis, Diogo Filipe Martins Gonçalves Neves & Fernando P. Bernardo, Computers & Industrial Engineering , Vol. 175, 108898 (Jan. 2023). This paper considers the container loading problem (CLP) for efficient packing of low density tissue paper products, for which, volume, instead of weight, is the key driver for logistic decision-making. Tissue products are susceptible to deformation during the packing process. However, this aspect is usually overlooked when defining the optimal packing policy. In this work, we take this aspect into account and develop a novel methodology for CLP optimization of tissue paper products. The deformation is modeled as a function of known product characteristics and packing process variables using data-driven models. Several modeling approaches are compared, including those based on variable selection, regularization and projection to latent variables. The data-driven model is then included into a Mixed Integer Non Linear Programming (MINLP) CLP. A worst-case robust optimization approach is considered, resulting in solutions that are robust against data-driven model uncertainty. The methodology is applied to a real case study from a portuguese tissue paper mill concerning the packing of toilet paper rolls in wood shipping pallets. Predicted results show an average gain of 4 to 7% in load density in the worst-case scenario, compared to current practice. The deformation model is validated experimentally on the industrial site,
Technical Abstracts
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