| 1. |
- Reyier Österling, Sofia, et al.
(författare)
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Weighted averages and distributions of fibre characteristics of mechanical pulps – Part II: Distributions of measured and predicted fibre characteristics by using raw data from an optical fibre analyser
- 2016
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Ingår i: Appita journal. - 1038-6807. ; 69:1, s. 64-73
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Tidskriftsartikel (refereegranskat)abstract
- Characterisation of fibres in mechanical pulps is important for process evaluation and control, and necessary to be able to optimise the refining process with respect to the total electric energy consumption. There are large variations of cross-sectional fibre characteristics in the wood raw material which influence the properties of the product. Despite this, it is common to evaluate the fibre characteristics as averages instead of distributions. This study shows that the raw data from a FiberLab analyser can be used to make distributions of measured and predicted fibre characteristics. The factor BIN (Bonding ability /Nfluence), which correlates to long fibre tensile index, includes both the external fibrillation and wall thickness of each fibre. Distributions of BIN, fibrillation and wall thickness which take the Characteristics of each fibre into Consideration have higher resolution than histograms. These distributions weighted by length and wall volume with maintained resolution revealed more information about the pulps than average values.
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| 2. |
- Reyier Österling, Sofia, et al.
(författare)
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Weighted averages and distributions of fibre characteristics of mechanical pulps Part I : Various methods of weighting data from an optical analyser can give averages that rank pulps differently
- 2015
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Ingår i: Appita journal. - 1038-6807. ; 68:4, s. 357-368
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Tidskriftsartikel (refereegranskat)abstract
- To improve the operation and energy efficiency of mechanical pulping processes, the effect of each stage of the process on the fibres should be carefully evaluated. Fibre-data from an optical analyser were used to predict tensile index by calculating BIN (Bonding ability /Nfluence). Wall volume weighted averages of wall thickness index and fibrillation index gave the most accurate predictions of the tensile index of laboratory sheets made from long fibre fractions of various mechanical pulps. Fibre width index, when used as a single factor, reduced the accuracy of the model. The ranking of some samples changed when fibre width was wall volume weighted compared to arithmetic. When fibre width was combined with wall thickness to give a collapse resistance index, no rankings changed. Weighted averages based on squared fibre length (length(2)) showed poor correlation to wall volume weighted averages for cross-sectional fibre dimensions, and resulted in different levels of correlation to long fibre tensile index for the five evaluated pulps.
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