126-131<span style="mso-ansi-language:
EN-IN;mso-bidi-language:FA">To study the effect of yarn twist on the
geometrical parameters of yarn in a plain woven fabric such as its
cross-sectional shape, the samples with various twist levels of warp and weft
yarns have been woven and the yarn cross-section parameters are measured using
their images obtained by Projectina microscope. The image processing analyses
show that the shape of yarn cross-section in the fabric is affected by the
twist level. The statistical analysis shows that the increase in yarn twist
factor (atex) from 0 to 4600 changes
the yarn cross-section shape into a lens shape and then elliptical shape and
finally circular-like shape. The major diameter of the elliptical shape of the
yarn cross-section decreases as the yarn twist increases, while the minor
diameter of the elliptical shape of yarn cross- section increases as the yarn
twist increases. The results also show that the twist of one group of yarns
(warp) affects the cross-sectional shape of other group of yarns (weft). The
ellipticity ratio of the yarns (minor diameter divided by major diameter)
increases from 0.35 to 0.86 as the yarn twist factor increases from 0 to 4600.
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