Mid Sweden University

Fibre properties significantly influence paper quality. This study investigates fibre property development along an industrial pulp production line, analysing morphological distributions and rheological behaviour to enhance refining performance indicators. Understanding these developments is critical for optimising resource efficiency and increasing industrial sustainability. Softwood thermomechanical pulp (TMP), from high-consistency (HC) and low-consistency (LC) refining, and bleached hardwood kraft pulp (BHKP) were examined. Fibre morphological properties were characterised using an optical fibre analyser, while suspension rheology was assessed using a pulp viscometer, supported by computational fluid dynamics (CFD) and discrete element method (DEM) simulations. Results demonstrate that fibre property distributions provide deeper insights into refining effects compared to average values alone. Systematic trends showed that HC-refined TMP from the first and second refining stage required significantly greater torque to break the fibrous network and fluidise the pulp compared to pulp that was also LC refined. This indicates that alterations in fibre properties, especially shortened fibre length resulting from different refining processes, govern fibre interactions in the three-dimensional network of the pulp suspensions and, therefore, their flow behaviour. In conclusion, combining morphological distribution analysis with specialised rheological measurements offers a robust tool for better understanding and monitoring mill-scale refining processes, enabling improved process optimisation in pulping and papermaking.

Integrating research into teaching is pivotal in fostering critical thinking, innovation, and lifelong learning,especially in an era of rapid technological advancements and global educational transformations.Research-based education bridges the gap between theoretical knowledge and practical application,equipping students with analytical skills, adaptability, and inquiry. However, many higher educationinstitutions struggle to implement research-integrated curricula due to financial constraints, failing toattract students to research-profile programs due to limited scholarships and inadequate institutionalvisibility. This challenge is evident in Sweden, where universities, including Mid Sweden University, facedifficulties securing sufficient research funding in some subject areas and do not provide scholarships,impacting institutional growth and student engagement. A strategic approach is essential, emphasizingincreased funding, fostering stronger international collaborations, and enhancing research visibility. Topromote an inquiry-driven learning culture, universities should implement structured teaching strategies,including research-oriented curricula, interactive workshops, and interdisciplinary collaborations. Facultymembers are critical in imparting knowledge, researching, and mentoring students. As the SwedishCouncil for Higher Education outlines, a knowledge-driven environment requires a commitment toacademic freedom and integrity, as emphasized in the Act on Responsibility for Good Research Practiceand the Examination of Research Misconduct (2019:504).

Swedish higher education operates under complex governance structures balancing academic autonomy,financial sustainability, and societal impact. This paper examines four institutional approaches—professional, managerial, developmental, and market-driven—that shape research integration ineducation. The professional approach, rooted in the Humboldtian model, emphasizes knowledge andacademic independence. The managerial approach prioritizes institutional ranking and resource allocation;the developmental approach focuses on continuous innovation in educational practices, while the marketdrivenapproach aligns knowledge production with economic imperatives, ensuring research addressesindustry needs and global demands. Looking ahead, universities may navigate these approaches byfocusing on research-driven strategies, prioritizing three key areas: expanding international partnerships,advancing sustainable research initiatives, and integrating digital technologies into academic programs.Strengthening interdisciplinary collaboration and promoting ethical research practices enhancesinstitutional competitiveness and contributes to societal progress. By combining research-based teachingwith institutional strategies, universities can develop an educational framework supporting inquiry-basedlearning, equipping students with critical skills to address global challenges. This fosters competencies fornavigating complexities, highlighting the importance of research-driven education in preparing graduates.

Ultimately, prioritizing suggested strategic areas to leverage research-driven approaches empowerseducators to transform learning, fostering an environment that encourages inquiry, critical thinking, andacademic excellence. Institutions can create an inclusive, knowledge-driven, and transformative systemby overcoming financial and structural challenges and effectively leveraging available resources.

There is a growing need for increased knowledge regarding sustainable and health-conscious menstrual products, particularly as environmental concerns intersect with public health, equality, and education. Our recent research presents the development and assessment of an internal menstrual product made from wood-based, biodegradable, fossil and plastic-free materials. Designed for safe use for at least 12 hours, the product addresses the practical needs of modern users across diverse cultural and socioeconomic contexts. Laboratory testing, including toxicological assessments, absorption efficiency, and biodegradability analyses, confirms that the product meets high standards of safety and environmental performance. The design process emphasized comfort, hygiene, and suitability for extended daily use without increasing health risks, such as Toxic Shock Syndrome. Patents are pending both regarding the product design and regarding the production process conditions.

To complement and assist the product development, an interactive 3D educational tool was created to enhance menstrual and reproductive health literacy. This tool, tailored for young users and low-resource settings, has been evaluated in collaboration with schools, youth clinics, and international NGOs in high and low-income countries. The initiative responds to the persistent stigma surrounding menstruation and the limited access to accurate, inclusive, and culturally adapted educational resources.

A key research focus has been integrating sustainable material innovation with health education and exploring the potential for international standardization. The project also initiated steps toward the first global safety standard for menstrual products under ISO, promoting transparency, user safety, and global market readiness. Through stakeholder engagement, user studies, and pilot-scale manufacturing, this work demonstrates how eco-friendly menstrual products can support environmental goals while empowering users through education and accessibility.

By combining product innovation, education, and policy development, this research contributes to UN Sustainable Development Goals such as: Good Health and Well-being (SDG 3), Quality Education (SDG 4), Gender Equality (SDG 5), and Responsible Consumption and Production (SDG 12). It offers a scalable, evidence-based framework for improving menstrual health globally.

This volume contains the abstracts presented at the Progress in Paper Physics Seminar 2025, held in Sundsvall, Sweden, on 20–22 May 2025. The contributions cover current research in paper physics, pulp and paper materials, cellulose fibre networks, paperboard mechanics, material characterization, converting processes, packaging applications, and related modelling and experimental methods.

Increased knowledge on the correlation between pulp processing, fibre-properties and paper properties is required to improve fibre-based products. Part 1 of this investigation deals with the effects of HC and LC refining on fibre properties development. LC refining reduced curl and increased tensile index in a manner similar to hot disintegration whereas HC refining increased curl slightly. In this second part, the correlation between fibre curl and handsheet properties of thermomechanical pulp, subjected to low consistency (LC) refining and hot/cold disintegration is examined. Fibre curl decreased by laboratory disintegration and LC refining and showed a linear correlation with increased tensile index and tensile stiffness. Evaluation of fibre property distributions gave a more detailed description of the development of fibre properties. These revealed that disintegration and LC refining gave different fibre curl versus fibre length distributions, even when their average values were similar. These results confirm that analysing fibre property distributions contributes to a more detailed knowledge of the development of pulp quality. Hot disintegration before laboratory testing exaggerated pulp quality and increase internal fibrillation and can therefore be questioned. When hot disintegration is performed before pulp analyses, the impact of LC refining on paper properties may be misjudged. 

We present a method for pulp particle characterization based on a truncated lognormal mixture (TLM) model, as motivated by size statistics of organisms. We use an optical fiber analyzer to measure the length–width distribution of kraft-cooked roundwood or sawmill sources, of chemi-thermomechanical pulp (CTMP) samples from roundwood or sawmill sources, and the same CTMP samples after kraft post-processing. Our results show that bimodal TLMs capture salient features of the investigated pulp particle distributions, by decomposition into a large-particle and a small-particle fraction. However, we find that fibers from sawmill sources, which have not undergone mechanical treatment, cannot be described by TLM, likely due to non-random sampling. Within the confines of our dataset, the TLM characterization predicts laboratory sheet properties more effectively than conventional averaging methods for pulp particle size distributions. The TLM characterization is intended as a tool for controlling the pulp production process towards higher product quality, uniformity, and energy efficiency, pending further mill trials for validation. 

In the pulp and paper industry, pulp testing is typically a labor-intensive process performed on hand-made laboratory sheets. Online quality control by automated image analysis and machine learning (ML) could provide a consistent, fast and cost-efficient alternative. In this study, four different supervised ML techniques—Lasso regression, support vector machine (SVM), feed-forward neural networks (FFNN), and recurrent neural networks (RNN)—were applied to fiber data obtained from fiber suspension micrographs analyzed by two separate image analysis software. With the built-in software of a commercial fiber analyzer optimized for speed, the maximum accuracy of 81% was achieved using the FFNN algorithm with Yeo–Johnson preprocessing. With an in-house algorithm adapted for ML by an extended set of particle attributes, a maximum accuracy of 96% was achieved with Lasso regression. A parameter capturing the average intensity of the particle in the micrograph, only available from the latter software, has a particularly strong predictive capability. The high accuracy and sensitivity of the ML results indicate that such a strategy could be very useful for quality control of fiber dispersions. 

Softwood pulp flow in rotating and non-rotating grooves is numerically simulated in the present study to investigate the fluid flow and the forces acting on a representative surface mounted in the groove. The viscosity of softwood pulp with various consistencies is available from the measurements reported in the literature providing the opportunity to examine the effects of fiber consistency on the velocity and pressure distribution within the groove. The simulations are carried out in OpenFOAM for different values of gap thickness, angular velocity and radial positions from which the pressure coefficient and shear forces values are obtained. It is found that the shear forces within the gap increase linearly with the angular velocity for all fiber consistencies investigated and in both grooves. Also, this behavior can be successfully predicted by modeling the gap flow as a Couette flow in a two-dimensional channel. Meanwhile, a more detailed analysis of the flow kinetic energy close to the stagnation point using Bernoulli's principle is carried out to provide a better understanding of the pressure coefficient variation with angular velocity in the non-rotating groove. A comparison of pressure coefficients obtained numerically with those calculated by considering the compression effects revealed that the comparison effects are dominating in the pulp flow within the groove.

The split Hopkinson pressure bar (SHPB) is a widely used method for analyzing the strength-strain characteristics of wood materials [1]. Experiments show that, as wood is a relatively soft material and the experimental setup is limited in size, the entire wave is not fully recorded before it is mixed with waves reflected from the ends. To be able to analyze how much energy is dissipated in a deformation process, it is required that the whole wave be recorded. In the present investigation, the pressure tail was reconstructed theoretically in the incident bar using the data from the transmission bar, which should allow for a reduction in the error in the energy of the waves.

When a deformation wave propagates along bars, part of its energy dissipates into the environment. In this study, a modification of the SHPB was proposed to calculate and analyze the amount of energy the system loses, not due to the sample. Formulas for energy and momentum equilibrium were used [2]. The influence of the length of the striker and the level of input energy were also analyzed.

In the presented experiment, all energy tails were completely recorded. This allowed for the theoretical reconstruction of the tail and a comparison with the recorded one. The pressure tail in the transmitted wave was manually shortened and replaced with a theoretical tail. The theoretical tail was created by performing an exponential curve fit with points from the tail up to the point where it had been shortened. The results show that only about 10% of the tail needs to be registered to accurately reconstruct it. When a registered wave is replaced with a reconstructed one, the resulting error in the total wave's energy value is no greater than 0.3% for a 500mm striker and 1.5% for a 250mm striker.

I dagens samhälle blir det allt viktigare att fortbilda sig under hela sitt yrkesverksamma liv. För att möta efterfrågan på det livslånga lärandet har Mittuniversitetet utvecklat och genomfört ett antal kurser som riktar sig mot yrkesverksamma ingenjörer. Detta arbete presenterar våra erfarenheter av att ge dessa kurser, med en tyngdpunkt på studenternas upplevelser. Syftet med detta är att bygga upp en vetenskaplig bas för vad vi gör som är bra, men även vad som kan förbättras och förändras. Målsättningen är att göra dessa specialanpassade kurser riktade mot yrkesverksamma ingenjörer så givande och flexibla som möjligt. Våra initiala resultat visar bland annat att studenternas negativa upplevelser ofta var kopplade till antagningsförfarandet och det praktiska genomförandet av kurserna. Man hade svårigheter med att hitta hur man skulle registrera sig på kursen och att tidsramen för registrering kunde vara ett problem. Läroplattformen uppfattades som svår att överblicka och det förekom även viss otydlighet gällande var undervisningen skulle äga rum. Den positiva responsen i utvärderingarna gällde främst det faktiska kursinnehållet, då man ansåg att uppgifter och kursmaterial var givande. Vidare uppskattades kursupplägget, att man kunde kombinera studierna med arbete. Framledes kommer vi att fortsätta med dessa utvärderingar i takt med att kurserna ges, och därefter anpassa vårt mottagande och kommunikationen med studenterna. Även kursupplägget ses över kontinuerligt via den återkoppling vi mottar.