PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 9, Number 1, 2023
morphology, chemical composition, crystallization, and chemical state structure, and paper performance were studied. Meanwhile, the mechanical performance of cow dung paper and the degradation of cow dung paper in soil were investigated in this work as well. At 100°C, the residue from cooking cow dung decreased and stabilized. Fiber yield in cow dung peaked at 10% KOH concentration. The lignin-hemicellulose C=O bonds were completely broken making the material softer and looser. At 42 °SR Schopper- Riegler’s Degree (SR) pulping, the polymerization was 1126, and the average fiber length and width were 1245 μm and 18.3 μm. Cow dung paper had the best mechanical performance at 42 °SR of 2.48 KPam 2 /g burst index, 4.83 mNm 2 /g tear index, and 26.72 Nm/g tensile index, respectively. This work demonstrates that cellulose fiber, extracted from cow dung, is suitable for paper applications and provides new insight into cow dung recycling. TESTING “Fast characterization of in -plane fiber orientation at the surface of paper sheets through image analysis ” , Paulo A.N. Dias et al, Chemometrics and Intelligent Laboratory Systems , Vol.234, 2023. The in-plane fiber orientation distribution has a decisive impact on paper mechanical and dimensional properties (e.g., tensile stiffness, hygroexpansion). It is usually estimated offline through relatively expensive bench instrumentation such as diffusion-based optical methods and ultrasonic devices. In this work we present an alternative methodology that is fast, portable, inexpensive and able to provide the complete surface polar fiber orientation profile. The proposed technology combines an image acquisition setup, consisting of a digital camera with a low angle illumination system, with the gradient-segmentation method (GSM), a robust image analysis algorithm. This camera-GSM methodology presented high internal consistency, accurately identifying the angles of samples subjected to known rotations at the imaging step. The methodology also produced comparable results to the TSO (tensile stiffness orientation) technique, used as reference. The methodology is easily transferable to plant operation, including for the online assessment of fiber orientation. “Torsional and compression loading of paperboard packages: Experimental and FE analysis”, Gustav Marin, Packaging Technology and Science , Vol.36(1), 2023. The present study investigates torsional and compressive loading of a paperboard package. Finite element (FE) analyses simulating the tests were performed to improve understanding of the stresses and deformations in the paperboard during loading. A simple experimental characterization of the necessary material properties could be performed to represent the multi-ply paperboard as a single-ply structure. The results from the single-ply model were compared with a laminate model, and the differences between the models were small. Comparing experimental and FE simulations of box compression and torsion showed that the FE models could accurately predict the response curves. However, in the simulations, there was an overprediction of the maximum compressive force and maximum torque, which was expected since geometrical imperfections and the heterogeneous internal structure of the material were not accounted for in the material model or the FE model. Local yield lines formed at the onset of non-linearities in the package load – displacement curves. Therefore, the strength of the paperboard affects the maximum compressive strength and maximum torque, and the bending stiffness of the paperboard only had a minor effect. When a first local maximum was reached, the number of FE that reached the failure stress increased exponentially. The simulations also showed that box compression was not an effect of package height, but higher packages had a lower maximum torque.
Technical Abstracts
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