Question

In fibre length analysis, Dispersion or Scatter is useful to determine

• A. Noil % at Comber
• B. Setting in Card
• C. Setting at Ring Frame
• D. Speed Frame

Hint:

Remember the relationship between fibre length distribution and combing: \[ \boxed{ \text{More Short Fibres} \Longrightarrow \text{Higher Dispersion} \Longrightarrow \text{Higher Noil \%} } \] Important fibre length parameters include: \[ \begin{aligned} &\bullet\ \text{Mean Fibre Length} &\bullet\ \text{Upper Half Mean Length} &\bullet\ \text{Uniformity Ratio} &\bullet\ \textbf{Dispersion (Scatter)} \end{aligned} \] A common examination point is: \[ \boxed{ \text{Dispersion} \Longrightarrow \text{Estimate of Noil \% at Comber} } \]

Answer 1

The Correct Option is A

Concept: Fibre length is one of the most important characteristics affecting the spinning performance and yarn quality. During fibre length analysis, not only the average fibre length but also the dispersion (or scatter) of fibre lengths is studied. Dispersion indicates how widely the fibre lengths are distributed around the mean length. A higher dispersion means a greater variation in fibre lengths, whereas a lower dispersion indicates more uniform fibres. Knowledge of fibre length distribution helps in selecting suitable machine settings and estimating the amount of short fibres that will be removed during processing.

Step 1: Understand the meaning of dispersion or scatter.
Dispersion is a statistical measure that describes the variation in fibre lengths within a sample. If a cotton sample contains a large number of short fibres, the spread of the length distribution increases. Therefore, \[ \boxed{ \text{Higher Dispersion} \Longrightarrow \text{Greater Percentage of Short Fibres} } \] Since combing removes short fibres, dispersion becomes an important indicator while estimating combing waste.

Step 2: Relation between dispersion and Noil.
During the combing process,
• Short fibres are removed.
• The removed fibres are called Noil.
• The quantity removed is expressed as Noil %. A fibre sample with greater scatter generally contains more short fibres, resulting in a higher percentage of noil. Hence, fibre length dispersion is particularly useful for determining \[ \boxed{\text{Noil \% at the Comber}.} \]

Step 3: Examine each option.
Option (A): Noil % at Comber Dispersion or scatter directly helps in estimating the amount of short fibres removed during combing. \[ \boxed{\text{Correct}} \] Option (B): Setting in Card Card settings depend mainly on fibre characteristics and machine design, not directly on dispersion analysis. \[ \boxed{\text{Incorrect}} \] Option (C): Setting at Ring Frame Ring frame settings are determined by yarn count and drafting requirements rather than fibre length dispersion. \[ \boxed{\text{Incorrect}} \] Option (D): Speed Frame Speed frame parameters are not determined directly from fibre length dispersion. \[ \boxed{\text{Incorrect}} \]

Step 4: Write the final answer.
Thus, dispersion or scatter obtained from fibre length analysis is mainly used to determine \[ \boxed{\text{Noil Percentage at the Comber}.} \] Therefore, \[ \boxed{\text{Option (A) is the correct answer.}} \]