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United States Department of Agriculture

Agricultural Research Service


item Davidonis, Gayle

Submitted to: Faserinstitute Bremen Cotton Exchange Meetings
Publication Type: Proceedings
Publication Acceptance Date: April 15, 2006
Publication Date: May 15, 2006
Citation: Montalvo Jr, J.G., Davidonis, G.H., Von Hoven, T.M. 2006. Relations between micronaire, fineness and maturity. Faserinstitute Bremen Cotton Exchange Meetings. CD-ROM. P. 45-56.

Interpretive Summary: Fineness and maturity are important fiber properties. This is because yarns made with fiber of fine perimeters are stronger and mature fibers with the thicker cellulose wall absorb dye better. The micronaire of cotton is a measure of both properties and there are strong associations between the parameters. Two instruments that have been used to measure fineness and maturity on U.S. cottons are the Fineness and Maturity Tester (FMT), and Advanced Fiber Information System (AFIS). There is a need to validate the results on both instruments. One way to probe a data set for error in instrument values is to extract diagnostic information about the associations between the properties. For this work, U.S. cottons were selected with different varieties and associations between the fiber properties evaluated. The specific association between micronaire and FMT values demonstrated that the FMT data is unbiased. However, the association between micronaire and AFIS values shows that the AFIS data is, in fact, biased. The practical implication of this research is that inaccurate AFIS fiber quality results are being given to the producer and consumer. Advances in this area of work may lead to more accurate classing data, which could positively impact U.S. cotton consumption.

Technical Abstract: Diagnostic models of the specific relationships between: (a) fineness/perimeter and the product of maturity x perimetner, (b) micronaire and fineness/perimeter, and (c) micronaire and the product of maturity x perimeter were tested on experimental data from U.S. cottons. The diagnostic models provide a tool to test fineness and maturity results for bias or a difference compared to the more traditional Lord Micronaire model. Perimeter's role in the model is to normalize the data and stabilize model output. Model output includes the linear regression coefficient of determination, slope and intercept. Two grops of cottons were evaluated in this study. One was analyzed by the Southern Regional Research Center (SRRC) upgraded Fineness and Maturity Tester (FMT) for all fiber properties (fineness, perimeter, maturity and micronaire). The other group was analyzed by the Advanced Fiber Information System (AFIS) for fineness, maturity and perimeter, and by a high volume instrument (HVI) for micronaire. Example results are as follows: Diagnostic model plots of the FMT data produced a high R-2 and with slopes and intercepts that conform to predictions. By contrast, the plot of the HVI micronaire and AFIS maturity x perimeter data gave results that were significantly different compared to model predictions. Simulation data with added error was used to help interpret the findings. The study indicated that the AFIS fineness and maturity values are biased compared to Lord's micronaire model. Recalibration is recommended.

Last Modified: 8/3/2015
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