Abstract: An ion-junction fibrous bridge and a potentiometric test element incorporating the same, wherein the fibers extending generally along the center-line between two liquid access apertures in the bridge, are readily capable of conducting aqueous liquid through the bridge, and fibers extending at an angle of at least 20 .degree. from said center-line are not readily capable of conducting aqueous liquid.

Abstract: A device is disclosed for determining ion activity in liquid solutions by the use of electrodes over which a cover sheet with an internal capillary bridge promotes ionic migration between the electrodes. The cover sheet is formed of a porous material ribbon encapsulated in a nonporous web. Preferably, the cover sheet is punched at each electrode to provide fluid access holes for receiving drops of liquid solutions.

Abstract: A device is disclosed for determining ion activity in liquid solutions by the use of electrodes over which a cover sheet with an internal capillary bridge promotes ionic migration between the electrodes. The cover sheet is formed of a porous material ribbon encapsulated in a nonporous web. Preferably, the cover sheet is punched at each electrode to provide fluid access holes for receiving drops of liquid solutions.

Abstract: Biaxially-oriented, heatset polyester film is heat relaxed at a uniform temperature and supported buy impingement with gas such as air, while subjecting the film to low tension in its longitudinal dimension. Undesirable draw lines, as defined herein, are avoided by maintaining the longitudinal dimension of the film in an arcuate configuration composed of a single curve or serpentine succession of curves free of straight segments. Each such curve is characterized as having a radius of curvature in the range from about 1 inch to about 8 inches, subtending an arc of no less than 40.degree.. A serpentine configuration is preferred in which case the gas impinges upon alternate sides of the web. Temperatures of heat relaxation preferably are within the range from 30 to 100 centrigrade degrees higher than the polyester glass transition temperature.

Abstract: A thermosensitive image-forming element is comprised of at least one image-forming layer and a biaxially-oriented heatset poly(ethylene terephthalate) film support which is capable of resisting dimensional distortion resulting from the combined effects of tension and heat. The element is processed by application of heat sufficient to form a visible image while maintaining the element under tension in its longitudinal dimension and no tension in its transverse dimension.