Definitions /Dictionary/Glossary - nptel

Tolerance Limit: A lower (upper) confidence limit on a specified percentile of a distribution.
For example, the B-basis value is a 95% lower confidence limit on the tenth percentile of a
distribution.
Tolerance Limit Factor: The factor which is multiplied by the estimate of variability in
computing the tolerance limit.
Tool: The mold, either one- or two-sided or either open or closed, in or upon which composite
material is placed in order to make a part.
Tooling Gel Coat/Laminating Resin: It is special polyesters designed to give ultimate strengths
and cure values for moldmaking.
Tooling Resins: Plastic resins, chiefly epoxy and silicon that are used as tooling aids.
Toughness: A measure of a material's ability to absorb work, or the actual work per unit volume
or unit mass of material that is required to rupture it. Toughness is proportional to the area under
the load-elongation curve from the origin to the breaking point.
Tow: An untwisted bundle of continuous filaments. It is commonly used in referring to manmade
fibers, particularly carbon and graphite fibers, in the composites industry.
Transformation: A transformation of data values is a change in the units of measurement
accomplished by applying a mathematical function to all data values. For example, if the data is
given by x, then y = x + 1, x, 1/x, log x, and cos(x) are transformations.
Transition, First Order: A change of state associated with crystallization or melting in a
polymer.
Translucent: Permits a percentage of light to pass but not optically clear like window glass.
Transversely Isotropic: Descriptive term for a material exhibiting a special case of orthotropy
in which properties are identical in two orthotropic dimensions, but not the third; having
identical properties in both transverse directions but not the longitudinal direction.
Traveller: A small piece of the same product (panel, tube, etc.) as the test specimen, used for
example to measure moisture content as a result of conditioning.
Twist: The number of turns about its axis per unit of length in a yarn or other textile strand. It
may be expressed as turns per inch (tpi) or turns per centimeter (tpcm).
Twist, Direction of: The direction of twist in yarns and other textile strands is indicated by the
capital letters S and Z. Yarn has S twist if, when held in a vertical position, the visible spirals or
helices around its central axis are in the direction of slope of the central portion of the letter S,
and Z twist is in the other direction.