Anthony M. Schwartz

The Migration of Liquids in Textile Assemblies: Part II: The Wicking of Liquids in Yams

Since a yam is not geometrically equivalent to a capillary tube we must substitute for r a suitably derived &dquo;equivalent radius&dquo; of the open cross-smtional area within the yarn. A numerical value four r in any given yarn is difhcult to determine. It may be assumed as a first approximation, for yarns composed of oriented cylindrical fibers, that r will be proportional to the square root of the open crosssectional area. This assumption is compatible with the concept of the hydraulic depth widely used in considering flow through porous media [ 3 ] . The only other factor in Expression 3 which might be ambiguous is the contact angle 8. In systems where there is hysteresis of the contact angle, the advancing

Adhesive Polyurethane Liners for Anterior Restorations

Polyurethane-type compositions were developed as adhesive liners for poly(methyl methacrylate) restorations. Several polyglycol-diisocyanate mixtures had excellent adhesion to human dentin when applied to moist teeth in vitro. Conventional acrylic restorations became durably bonded when applied on top of these urethane liners within 15 to 30 minutes.

The Migration of Liquids in Textile Assemblies: Part V: Two-Component and Two-Phase Liquid Systems

dye, Calcozine Green, and cross sections were examined under the microscope. Since the dye colors polyacrylonitrile to a fairly deep shade yet barely stains cellulose, the location of the polymer could be readily observed. It was found that the fibers were almost completely penetrated by the polymer deposits, although the polymer concentration appeared to he greater near the surface. The same was found

The Migration of Liquids in Textile Assemblies: Part IV: Penetration of Fabrics by Liquids

ferred to a sl1itably selected underlying surface or substrate. Thus. if a dfop of liquid is plared on the outside of a protective garment, the inside of which rests against the weafer’s skin, penetration is said to occur if any of the liyuicl makes contact with the skin. If the inside of the garment rests against an absorbent substrate, such as a piece of 1)1()ttiiig paper.the penetration can be measured ql1él11titatively by comparing the amount of liquid collecte(i in the 1)1()ttiiig paper (after a stipulated time with the amount c~rit;ittallv placed on the outside of the