# GATE (TF) Textile 2009 Question Paper Solution | GATE/2009/TF/15

###### Question 15 (Textile Engineering & Fibre Science)

Uniformly ratio for normal variety of cotton is in the range

Option B is correct

### What do you mean by uniformity ratio and uniformity index?

In the context of textiles, the terms “uniformity ratio” and “uniformity index” are used to quantify the evenness or uniformity of a fabric or yarn. These parameters provide numerical values that indicate the level of variation present in the sample.
Uniformity Ratio: The uniformity ratio is a measure of the variation in thickness or diameter of a yarn or fabric. It is calculated by dividing the maximum value by the minimum value of the measured parameter. For example, in yarn testing, the thickness of the yarn is measured at multiple points along its length. The uniformity ratio is obtained by dividing the maximum measured thickness by the minimum measured thickness.
The uniformity ratio reflects the extent of variation in the sample, with higher values indicating greater unevenness. A uniformity ratio closer to 1 suggests a more uniform or even sample, while a higher ratio implies a larger difference between the thickest and thinnest areas.
Uniformity Index: The uniformity index is another measure of the evenness of a fabric or yarn, and it is often calculated using the “CV%” (coefficient of variation) or “CVm%” (coefficient of variation of mass). The coefficient of variation is a statistical measure that expresses the standard deviation as a percentage of the mean.

In yarn testing, the uniformity index (CV%) is calculated by dividing the standard deviation of the yarn thickness measurements by the average thickness and multiplying by 100. Similarly, in fabric testing, the uniformity index can be obtained by calculating the coefficient of variation for various parameters such as fabric thickness or density.

The uniformity index provides a relative measure of the variation in the sample, allowing for comparison between different samples or production runs. Lower uniformity index values indicate a higher degree of uniformity, while higher values suggest more pronounced variations in the sample.

Both the uniformity ratio and uniformity index are important parameters in the textile industry, as they help assess the quality, performance, and suitability of fabrics or yarns for various applications. Manufacturers and textile professionals use these measures to monitor production processes, identify potential issues, and make improvements to achieve desired levels of evenness and consistency.