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Diffusion of the Laser Radiation to Characterise the Paper Fibre Orientation an...
PEREIRA, M.J.T.; P.T.Fiadeiro; F.M.P.B.FerreiraThis work concerns the determination of fiber orientation in the paper sheet and possibly the mass density distribution. Both parameters strongly influence the quality of the paper for end uses in printing and converting. The measurement of such parameters is done using different approaches, most commonly indirectly from the determination of the paper's physical properties. The measurement and analysis of ...
O índice e a direcção de rigidez na quantificação da orientação das fibras no p...
PEREIRA, M.J.T.; P.T. FiadeiroAs técnicas ultra-sónicas encontram-se amplamente divulgadas na indústria do papel para medição do índice de rigidez (TSI) das folhas de papel. Para a indústria do papel o valor deste índice é assumido como sendo igual à anisotropia de orientação das fibras, o que acontece só quando a folha de papel é seca sem estar sujeita a tensões internas ou elongações. De forma a medir unicamente a anisotropia de orientaçã...
3-D Characterisation of Nonwoven Fabrics by means of an optical system
PEREIRA, M.J.T.; L. R. Salvado; P. T. Fiadeiro; J. SilvyThe characterisation of fabric structure by means of quantified parameters is essential for the control of the fabrication processes and the resulting properties of the nonwoven materials. Important parameters of the structure are the porosity, the mean pore size and the pore size distribution, the specific area of the texture, the fibres orientation the last one needing to be characterised in the three dimensi...
Structure of papers and Nonwovens
PEREIRA, M.J.T.; A.P. Costa; R. Salvado; J. Silvy; P.T. FiadeiroWe characterise the structure of fibrous materials: papers and nonwovens by diffraction and transmission of light. This allows the measurement of the fibres orientation distribution of the sample as a whole or for the surfaces using replicas. Applications of the methods are demonstrated in the case of paper for the control of the curl tendency and for two kinds of nonwoven materials, one used in the tailoring o...
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