Abstract: Phosphorescent screens which are useful for such purposes as intensifying screens for radiographs are comprised of a support on which is coated a layer of finely-divided particles of a phosphor dispersed in a polymeric binder which has been cured by radiation. The phosphor layer includes voids formed by evaporation of a component which is present in the coating composition from which such layer is formed. Curing of the binder is carried out by use of suitable radiation, such as ultraviolet light or high energy ionizing radiation, and evaporation of the void forming component is carried out simultaneously with or subsequent to the radiation-curing of the binder.

Abstract: The first normal stress function of a viscoelastic material which is a measure of its elasticity and a more sensitive indication of certain other parameters of the material, and process conditions, than the viscosity thereof, is determined from measurements of the thrust in a direction normal to the inner and outer walls of an annular channel in which the viscoelastic fluid material flows under pressure, at high shear rates in an angular direction. These thrust measurements may be made under regulated flow so as to eliminate the need for alignment of the positions at which the thrust measurements are made. The measurement system is closed so that evaporation and degradation of the fluid material as may occur in such systems as are open to the atmosphere are avoided. The first normal stress function may be determined over a broad range of shear rates such as are experienced in polymer processing (e.g., extrusion and injection molding) so as to facilitate continuous or real time process control.