NC State
BioResources
  • 1981
    Cambridge
    pp 603-633A. Komppa and K. EbelingCorrelation Between the Areal Mass and Optical Densities in PaperAbstractPDF

    The aim of the present investigation is to find out those variables of the paper-making process that cause variation in the light transmission of paper, independently of basis weight variation. Furthermore, is intended to discover under what conditions and to what accuracy the distribution of areal mass (formation) can be characterised by the areal distribution of light transmittance. The study is carried out by measuring values of beta-ray transmission and light transmission at exactly the same points of paper samples using an aperture of 1 mm diameter and analysing the correlation of the results.

    At this stage of the study the effects of furnish composition, beating, wet pressing, and calendering on the correlation between mass distribution and distribution of transmittance have been analysed. It can be seen that at least prolonged beating and heavy calendering change the distribution of transmittance in such a way that the optical formation measurement does not give a true picture of the distribution of mass.

  • 1981
    Cambridge
    pp 571-584Heinz Corte, Kevin Blinco, and Sheena HurstFracture Modes of Sheet MaterialsAbstractPDF

    I would like to draw your attention to the fact that the fibres of which paper is made retain their individuality in the sheet, even in dense papers.

    In many experiments, conditions are such that the discontinuous structure of paper has little chance to show. This is why the modulus of elasticity, for example, comes out the same whether it is determined by bending, by a sonic method, or by stretching in a tensile tester of standardized inertia. Such experiments assure us that the laws of continuum physics are consistent and that it is still worth reading and studying them.