Other

The State University of New York

Philip Luner

Hiroshi Tomimasu

Petri Silenius

Matti Lindstrom

The invention relates to a procedure for determining a quantity dependent on the rate of diffusion in the fibre wall for diffusion occurring through it, in which procedure a diffusible tracer is introduced into the fibres under measurement, the fibres are suspended in an aqueous phase and the tracer concentration is determined after a certain time has elapsed since the time of suspension of the fibres, and the quantity dependent on the rate of diffusion is calculated on the basis of the concentration and time. In addition, the invention relates to a procedure for determining the proportion of secondary fibre in a fibre suspension containing primary fibre and secondary fibre, in which procedure virtual diffusion coefficients are determined in the fibre wall for diffusion taking place through it in at least two fibre suspensions for which the proportions of primary and secondary fibre are known and in a fibre suspension under measurement, and that the proportion of secondary fibre in the suspension under measurement is estimated by assuming that the diffusion coefficient depends mainly linearly on the proportion of primary and secondary fibre in the fibre suspension.

Procedure for determining the diffusion coefficient prevailing in a

Distribution of mass density of paper or other materials is determined by irradiating a sample with a burst of electron beams from an electron gun. The intensity levels of electron beams emerging from said sample are detected by an areal detector located immediately behind the sample. These intensity levels are processed to derive distribution of mass density information for the sample. The electron beam detector may be a photographic film or a realtime electron beam detector assembly coupled to computer controlled digital data processing and displaying equipment.

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Syracuse, NY, United States of America

Philip Luner