Textile Glossary - Y

YARDAGE: The amount or length of a fabric expressed in yards. 

YARD GOODS: Fabric sold on a retail basis by the running yard. 

YARN: A generic term for a continuous strand of textile fibers, filaments, or material in a form suitable for knitting, weaving, or otherwise intertwining to form a textile fabric. Yarn occurs in the following forms: (1) a number of fibers twisted together (spun yarn); (2) a number of filaments laid together without twist (a zero-twist yarn); (3) a number of filaments laid together with a degree of twist; (4) a single filament with or without twist (a monofilament); or (5) a narrow strip of material, such as paper, plastic film, or metal foil, with or without twist, intended for use in a textile construction. 

YARN CONSTRUCTION: A term used to indicate the number of singles yarns and the number of strands combined for form each successive unit of a plied yarn or cord. 

YARN DYEING: See DYEING. 

YARN DYEING DIFFERENCES: Variations in take-up of dyes by yarns, resulting in streaks in finished fabrics. 

YARN INTERMEDIATE: A generic term for products obtained during the conversion of fibers to yarn, including card webs, laps, slivers, rovings, and tops. 

YARN NUMBER: A relative measure of the fineness of yarns. Two classes of systems are in use: (1) Direct yarn number (equal to linear density) is the mass per unit length of yarn. This system is used for silk and manufactured filament yarns. (2) Indirect yarn number (equal to the reciprocal of linear density) is the length per unit mass of yarn. This system is used for cotton, linen, and wool-type spun yarns. (Also see COTTON COUNT.) 

YARN NUMBER, EQUIVALENT SINGLE: The number of a plied yarn or cord determined by the standard methods used for singles yarns. 

YARN QUALITY: Various grades of yarn designated by the producer with respect to performance characteristics, e.g., first quality, second quality, etc. 

YARN-TO-CORD CONVERSION EFFICIENCY: In tire cord, this is a measurement relating tensile strength of untwisted yarn to tensile strength of cord. Increasing cord twist or increasing yarn diameter lowers conversion efficiency. 

YARN VARIATION: See RING. 

YELLOWNESS COEFFICIENT: Measure of the color of a molded acetate disc or dope solution. Cy = 1-T4400/T6400 where Cy is the yellowness coefficient; T4400 is the transmission at 4400A (blue); and T6400 is the transmission at 6400A (orange). 

YIELD:

1. Number of linear or square yards of fabric per pound of fiber or yarn.
2. The number of finished square yards per pound of greige fabric. 

YIELD POINT: Point on the stress-strain curve where the load and elongation stop being directly proportional. (Also see ELASTIC LIMIT.) 

YOUNG’S MODULUS: A property of perfectly elastic materials, it is the ratio of change in stress to change in strain within the elastic limits of the material. The ratio is calculated from the stress expressed in force per unit cross sectional area, and the strain expressed as a fraction of the original length. Modulus so calculated is equivalent to the force required to strain the sample 100% of its original length, at the rate prevailing below the elastic limit.