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United States Department of Agriculture

Agricultural Research Service

Research Project: New and Improved Assessments of Cotton Quality

Location: Cotton Structure and Quality Research

2013 Annual Report

1a. Objectives (from AD-416):
Objective 1: Develop new industrially supported methods to assess cotton quality. Sub-objective 1a: Develop ways to characterize short fibers in cotton. Sub-objective 1b: Develop methods to measure seed coat fragments. Sub-objective 1c: Develop assessment methods for cotton properties that may contribute to cotton textile processability and product quality, but not conventionally assessed, such as micronaire and its components (such as maturity), three-dimensional color, and environmental impact on fiber properties. Objective 2: Develop new industrially supported methods to establish scientific foundations for standards and the next generation instruments for cotton classing. Sub-objective 2a: Develop new algorithms and methods to obtain fiber length distributions from a rapid fiber beard testing method. Sub-objective 2b: Characterize the distributions of key cotton properties as well as single cotton fiber measurement. Objective 3: Develop new industrially supported assessment techniques and methods for cotton producers, breeders, and others to evaluate fiber properties at various fiber development or processing stages based on small samples. Sub-objective 3a: Develop assessment techniques and methods to evaluate fiber properties at various fiber development stages based through sampling/measurement of the cotton product at-line and/or in the cotton field. Sub-objective 3b: Develop assessment techniques and methods to evaluate fiber properties and textile products during processing stages of small samples of fiber into textile goods.

1b. Approach (from AD-416):
This research is a comprehensive effort to develop improved or new testing methods that are not currently in the cotton classing system so that the textile manufacturers can more efficiently select and utilize cotton to reduce cost and improve product quality and so that our international customers can get quantified U.S. cotton quality. The value of adding new measurements will be studied by processing large numbers of cotton samples into textile yarns and fabrics. The first objective develops new methods to assess cotton quality. Statistical modeling will be used to characterize short fibers in cotton. An automated image analysis system will be developed to relate seed coat fragments to textile processability and product quality. Microscopy and molecular spectroscopy will be used to develop measurement methods and to characterize fiber micronaire and its components (maturity, fineness). Advanced color and spectroscopic instrumentation, combined with statistical modeling, will be used to measure color and trash components. A room whose environment (moisture level) can be changed and controlled will be used to determine the impacts of moisture on quality assessments and instrumentation. The second objective develops methods for fiber length distributions and single fiber measurements. New beard methods and statistical modeling will be used to obtain fiber length distributions. Automated constant-rate of transverse tensile testers and statistical modeling will be used to monitor key single fiber properties (strength, fineness, etc.) and to establish relationships between single fiber properties and conventional bulk properties. The third objective develops new quality assessment tools for cotton breeders and others to evaluate fiber properties at various fiber development or processing stages based on small samples. New molecular spectroscopy, imaging, and textile instrumentation will be used to assess fiber properties and quality at-line or in the field. Very small scale processing systems (50-100 grams) will be developed and used to assess fiber properties and processability from carding to knitting or weaving on miniature equipment.

3. Progress Report:
ARS scientists in New Orleans, LA selected a large amount of cotton samples from commercial bales and experimental varieties and measured them on various traditional and newly developed methods. The models were refined and included new fiber quality parameters to more accurately predicted yarn properties. After completing a thorough patent and literature review, ARS Scientists have started to develop an updated reference method as the basis of comparability for seed coat fragment measurement. ARS scientists made progress developing assessment methods for cotton properties that contribute to cotton textile processability and product quality, but not conventionally assessed. The Cottonscope has shown to be very effective for the rapid and accurate measurement of cotton fiber maturity and fineness. To expand its use to non-standard laboratory conditions, the impacts of environmental conditions and operation procedures on the test results were determined. The investigation demonstrated that most of the results were impacted by large changes in temperature-RH, but only fineness was significantly impacted. Means to minimize the environmental condition impact are being evaluated. In addition, Fourier transform infrared and Near Infrared (NIR) spectroscopy techniques were used to reveal the relationships among fiber maturity, fiber growth periods, infrared crystallinity, maturity, fiber bundle tenacity and elongation. Visiable/NIR model to predict leaf grade and to differentiate cotton trash components was developed. As a natural product, cotton properties show wide distributions. The current cotton classing methods can not measure distributions. Therefore, ARS scientists focused on new rapid methods to obtain the distributions of fiber length, strength and color. Models have been developed to obtain length distribution from bulk length test method; work is underway to acquire the distributions of other key cotton properties from bulk fiber measurements; and a new method is being developed to measure cotton color distribution using image analysis, which has shown significant advantage over the current method. A new ultra-small (fits in your hand) NIR spectrometer was introduced for micronaire measurements in the laboratory (pre-field analyses). The NIR measurement was easy to perform, fast, and no sample preparation was required. An initial laboratory NIR method for micronaire was developed. The results from the laboratory trials were very encouraging and clearly demonstrated the potential of using this portable unit for field analyses. Complete overhaul of the textile pilot plant processing line has been carried out with equipment from the Cotton Quality Research Station (Clemson, SC). In addition to in-house research projects, samples from stake holders, the industry and other ARS Scientists were processed through both the small-scale and miniature-scale processing. Breeder samples have been processed on the small-scale equipment in order to evaluate fiber properties and assess the use of this processing technique as a tool for breeders. All of the data is cataloged and stored as part of a comprehensive database.

4. Accomplishments
1. Cooperation/support from stakeholders. Trust and reimbursable trust agreements are in place in FY 2013 with Cotton Incorporated on: color distributions by image analysis; color at-line/portable color measurements; Cottonscope maturity and fineness measurements for researchers, mills, and breeders; evaluation of the new Fibrotest instrument and incorporation of LHML into its software; impact of storage time and condition on bale cotton quality and quality; Near Infrared fiber measurements for breeders; bark (trash) detection by spectroscopy; and fiber moisture measurements. Cotton Incorporated was enabled by the Cotton Research and Promotion Act of 1966 and is the research and promotion arm of the cotton industry. The funding of the agreements demonstrates that the scientists of Cotton Structure and Quality are working closely with stockholders to address high impact issues of the cotton industry.

2. On-site cotton color measurements with portable color spectrophotometers. It has been reported that some cotton bales, especially those transported outside of the U.S., appear to have changed significantly in yellowness from their initial Uster® High Volume Instrument (HVI) classification color measurements. Although accurate, the HVI system is very expensive, requires trained operators, and is applicable to only laboratory measurements under standard environmental conditions. A remote color measurement protocol and system for laboratory and on-site (mill, warehouse; non-standard environmental conditions) fiber color measurements was developed and verified in the field, which resulted in the direct measurement of fiber color parameters Rd (diffuse reflectance) and +b (yellowness) in remote locations. A color spectrophotometer verification program was developed and optimized that established procedures and protocols and end-state agreement criteria for inter-instrument agreement between present and future color spectrophotometers (Agency is lead for the verification program). The technology was transferred to Cotton Incorporated and incorporated into their Engineering Fiber Selection System’s (EFS®) MILLNet™ software for mill bale selection. To date, three portable spectrophotometer units have been set-up, verified, and transferred to Cotton Incorporated for field use.

3. Fiber maturity and fineness measurement for breeder varieties. Most direct measurements of cotton fiber maturity and fineness involve the use of slow, laborious cross-sectional image analysis and microscopy; chemicals; or expensive fiber testing instruments. The Cottonscope, a new commercial instrument, measures fiber maturity and fineness directly (polarized light microscopy and image analysis in a water-based system), and a MTA and program was implemented with manufacturer to assess the Cottonscope’s capabilities. Analytical methods were developed for routine cotton lint (ginned cotton fiber) that results in the rapid, precise, and accurate measurement of fiber maturity and fineness. The program was expanded to emphasize small quantities of cotton near isogenic lines (NILs) developed by breeders (new varieties) with analytical methods developed for measurement of breeder samples with very small sample size (down to 10 mg). The measurement was overall fast, accurate, easy to perform, and required minimum sample preparation, with distinct changes in maturity values and distributions and in fineness values with increasing days post anthesis (DPA) observed and maturity and fineness results superior (more responsive/larger gain) to those from the Uster® Advanced Fiber Information System (AFIS). These results demonstrated that the Cottonscope’s maturity distributions can provide valuable information on maturity development and maturity variability at specific developmental stages of cotton fibers, and the Cottonscope method is in use by breeders at the Southern Regional Research Center, and a joint evaluation with an academic breeder will begin this season.

4. Expanded sample weight range for Cottonscope fiber maturity and fineness measurements. The Cottonscope rapidly, accurately, and precisely measures fiber maturity and fineness with small quantities of sample (approximately 50 milligram or mg), and interest has been expressed in the use of different sample weights of fiber, especially by breeders for lower sample weights. A program was implemented to establish the potential and capabilities of the Cottonscope to rapidly and accurately measure maturity, fineness, and ribbon width with different fiber sample weights (10-90 mg). The change in sample weight did impact the Cottonscope results for maturity (MR), fineness, and ribbon width, with fineness being most impacted, but re-calibration methods were developed that removed the impacts of sample weights on the Cottonscope results. Increasing the sample weight above the standard 50 mg of fiber did not appreciably reduce sample measurement times, but decreasing the sample weight below 50 mg did increase sample measurement times, especially at 10 mg sample weight; for cases where reduced analysis time is a primary concern, analytical methods were developed in which the number of fibers measured could be reduced 50% with minimal impact on the Cottonscope results (except for 10 mg sample weight). The feasibility and versatility of the Cottonscope to accurately and precisely measure the cotton fiber maturity, fineness, and ribbon width were demonstrated for small samples, down to 10 mg sample weight, thus providing an increased capability for breeders to obtain accurate and precise fiber maturity and fineness results on very small quantity samples for new or modified cotton varieties.

5. Comparisons of Near Infrared (NIR) instruments for laboratory fiber measurements. Laboratory techniques have been developed for the measurement of cotton fiber micronaire in the laboratory by Near Infrared (NIR) spectrometers. Although micronaire is an important cotton fiber property (it can impact the fiber’s downstream performance), its measurement is an indirect measurement of the fiber’s maturity. Multiple bench-top and portable NIR spectrometers were compared to establish the feasibility of both bench-top and portable NIR systems to monitor fiber micronaire and maturity in the laboratory prior to field evaluations. NIR instrumental, sampling, and operational procedures and protocols were developed, and NIR techniques for simultaneous measurement of fiber micronaire and maturity were developed and demonstrated. The NIR micronaire and maturity measurements were rapid, accurate, easy to perform, and no sample preparation was required. The developed laboratory procedures and techniques will be used as the basis of field trails to determine the feasibility of cotton field/at-line measurements of cotton fiber micronaire and maturity by portable NIR spectrometers.

6. A new method has been developed to measure cotton color distribution and variation by color image analysis method. As a natural product, cotton color has a distribution and variation within the same sample, which may indicate the variation of fiber quality that influences the quality of its textile product. Currently the colorimeter method for measuring cotton color provides the overall color grade; but it is not capable of measuring the within-sample color distribution and variation. A new method has been developed to measure distribution and variation of cotton color by using color image analysis and statistical analysis. By using this method, ARS Scientists at SRRC in New Orleans, LA revealed that for a cotton, the withina-sample color has a distribution that spans over a large range of color grades and cottons with same average color grade may have very different distributions. ARS scientists at SRRC in New Orleans, LA further demonstrated color distribution can be described by using the bivariate normal distribution and the distributions’ locations, shapes, orientations, and sizes can be quantitatively analyzed to characterize cotton color quality. This technology showed significant advantage than the current color measurement method and has a high potential to be used in new instrumentation. Cotton breeders, researchers, merchants and textile manufactures benefit from this technology since it provides a more detailed evaluation of cotton color property not available from any other method.

7. Samples from a wide variety of domestic and international breeding and research trials have been gathered and analyzer. Samples collected and analyzed include upland (G. hirsutum) and Extra Long Staple varieties (G. barbadense) as well as less common species (G. arboreum and G. herbaceum). The Fibrotest instrument has been installed and evaluated as a new bulk property measurement instrument. Techniques to obtain distributions of some properties from the Fibrotest instrument are being developed.

8. Over 1000 breeder and research samples have been processed on the miniature-scale processing system. Samples have been processed for comparison to large-scale processing and in-support of cotton breeders and researchers. The small-scale production of yarn for the National Cotton Variety Trials (NCVT) has been successfully brought in-house from an outside vendor through the development of successful small-scale processing techniques and methodologies. Small-scale fabric formation has been optimized and used in direct support of public researchers and the domestic textile industry.

9. Cotton leaf grade (trash) classification. Presence of trash (or non-lint fiber materials) in commercial cotton bales at varying amounts degrades their market values, requires additional cleaning process, and impacts the end-use qualities for yarn and fabric products. In order to meet the challenge of assessing the trash content, the USDA Agricultural Marketing Service (AMS) has implemented an index termed leaf grade, which is determined by qualified USDA’s AMS cotton classers via a visual inspection procedure. Lately, the AMS has revised the protocol for cotton leaf grade classification, by replacing the classer’s leaf determination with instrumental leaf measurement from cotton classification High Volume Index system. To look for a rapid and low-cost method that can be used away from the laboratory and in places such as ginning sites, ARS researchers at New Orleans, LA, developed the visible and near infrared (NIR) technique in the discrimination of cotton samples with various leaf grade categories, with an acceptable separation of ~ 95.0%. The outcome provides cotton fiber / textile engineers, researchers and regulators a new methodology for rapid, non-destructive, and routine determination of cotton leaf grade.

10. Cotton fiber maturation. Cotton fibers are natural plant products and their end-use qualities depend on their growth periods (or maturation). In general, there are significant differences in compositions, structures and end-use qualities between mature and immature (underdeveloped) fibers. Various physical and chemical techniques have been used to measure maturity. ARS Scientists at SRRC in New Orleans, LA used the Fourier transform infrared (FT-IR) spectroscopy as an alternative essential tool, as it permits routine analysis and is sensitive to delicate structure on fiber cellulose. ARS researchers quantified maturity ratio and crystallinity of immature fibers by use of FT-IR method. The outcome provides cotton fiber / textile engineers, researchers and regulators a new sight in applying FT-IR technique for rapid and routine sensing of cotton maturity and crystallinity.

Review Publications
Liu, Y. 2013. Recent progress in Fourier Transform Infrared (FTIR) spectroscopy study of compositional, structural, and physical attributes of developmental cotton fibers. Materials. 6(1):299-313.

Bel, P., Bugao, X., Boykin, D.L. 2012. Automatic detection of seed coat fragments in cotton fabrics. Textile Research Journal. 82(16):1711-1719.

Liu, Y., Thibodeaux, D.P., Gamble, G.R. 2012. Relationship between three cotton trash measurements and near infrared spectral response. Journal of Cotton Science. 16:272–281.

Rodgers III, J.E., Delhom, C.D., Hinchliffe, D.J., Kim, H.J., Cui, X. 2013. A rapid measurement for cotton breeders of maturity and fineness from developing and mature fibers. Textile Research Journal. 83(14):1439-1451.

Liu, Y., Foulk, J.A. 2013. Potential of visible and near infrared spectroscopy in the determination of instrumental leaf grade in lint cottons. Textile Research Journal. 83(9):928-936.

Long, R.L., Bange, M.P., Delhom, C.D., Church, J.A., Constable, G.A. 2013. An assessment of alternative cotton fibre quality attributes and their relationship with yarn strength. Crop and Pasture Science. 64(8):750-762.

Cai, Y., Cui, X., Rodgers III, J.E., Thibodeaux, D.P., Martin, V., Watson, M., Pang, S. 2013. A comparative study on cotton fiber length parameters’ effects on modeling yarn property. Textile Research Journal. 83: 961-970. DOI: 10.1177/0040517512468821.

Last Modified: 05/24/2017
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