3m Innovative Properties Company

Dean E Feyma

Craig S Chamberlain

Elaine M Yorkgitis

Steven J Heilig

A method of measuring inductance or inductive reactance of a sample is provided. The method comprises the steps of: (a) providing an instrument for measuring the inductance or the inductive reactance of the sample; (b) subjecting a portion of the instrument to different temperatures and recording data corresponding to the performance of the instrument portion at each temperature; (c) measuring the inductance or the inductive reactance of the sample using the instrument; and (d) correcting the measurement of inductance or inductive reactance for temperature based on the performance data.

Method for measuring stress levels in polymeric compositions

A method for measuring the level of stress in a polymeric or pre-polymeric composition within a given volume that includes combining the polymeric or pre-polymeric composition with a plurality of microparticles having a non-ferromagnetic or non-ferrimagnetic core provided with a coating that is ferromagnetic or ferrimagnetic to form an admixture in which the microparticles are substantially uniformly dispersed throughout the composition. The microparticles have a detectable magnetic characteristic which correlates with level of stress in the composition within a given volume. The change in the magnetic characteristic of the microparticles is then measured to determine the level of stress in the composition within a given volume.

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Sandstone, MN, United States of America

Dean E Feyma