Xiaoliang Cui

Identification of cotton and cotton trash components by Fourier transform near-infrared spectroscopy

The high demand for cotton production worldwide has demonstrated the need for standardized classification of foreign matter present with cotton. Cotton trash can become comingled with fiber during the ginning and harvesting processes. The conventional instrumental method used to determine the amount of cotton trash present with cotton fiber, the high volume instrument (HVI), lacks specificity in the identification of individual trash components (leaf, etc.). Fourier transform near-infrared (FT-NIR) spectroscopy was investigated to distinguish the individual types of cotton trash from the fiber. In this study, the concept of monitoring differences in spectral bands of cotton and cotton trash by FT-NIR spectroscopy was demonstrated and provided a ‘proof of concept.’ A spectral library based on NIR spectral data and pre-processing methods was developed using cotton and cotton trash samples (hull, leaf, seed coat, and stem) yielding over 97% identification accuracy of cotton trash components in the prediction set.

Near Infrared Measurement of Cotton Fiber Micronaire by Portable Near Infrared Instrumentation

In the U.S.A., cotton is classed (primary quality parameters) by the Uster ® High Volume Instrument (HVI), which must be maintained under tightly controlled laboratory environmental conditions. Improved and fast response quality measurement systems and tools are needed to rapidly assess the quality of cotton. One key area of emphasis and need is the development and implementation of new fast-response quality measurements that can be used not only in the laboratory but which also can be adapted to field and at-line quality measurements. A program was implemented to determine the ability of portable near-infrared (NIR) instrumentation to monitor critical fiber properties of cotton samples in the laboratory, at-line, and in the field, with initial emphasis on the laboratory measurement of cotton fiber micronaire. Micronaire is a key cotton property, and it is an indicator of the fiber’s maturity and fineness. Distinct NIR spectral differences between samples with varying micronaire were observed. A comparative evaluation was performed to determine optimum instrumental conditions for laboratory cotton micronaire measurements. The comparative evaluation established that the optimum instrumental conditions for laboratory measurements of micronaire was obtained with the use of a glass-covered sampling port and increased instrumental gain, with high R 2 values, low residuals, and with ≤ 12% outliers. For a NIR measurement with potential for multiple simultaneous analyses and non-laboratory measurements, the micronaire measurement was fast (< 3 min per sample) and easy to perform. The rapid and accurate laboratory measurement of cotton fiber micronaire with portable NIR instrumentation was demonstrated.

Measuring the short fiber content of cotton

A selection of cotton samples is tested with the Suter-Webb Array, AFIS (advanced fiber information system), and HVI (high volume instrument) methods. Short fiber contents as measured by these different methods show significant differences and high variations. The calibration level is one of the major factors causing these differences. Provided all other conditions are the same, a shift of 0.01 inch in fiber length calibration can cause an approximately 0.37% absolute value change in measured short fiber content based on the average of the test data. Based on the results from AFIS tests and computer simulation, sample nonuniformity, which is a characteristic of cotton fibers, contributes a major portion of the variation of the measured short fiber content.

A rapid measurement for cotton breeders of maturity and fineness from developing and mature fibers

The Cottonscope simultaneously measures a cotton fiber’s maturity and fineness using a small amount of fiber sample. A program of testing was devised to establish the potential and capabilities of the Cottonscope to rapidly and accurately measure maturity and fineness of small quantities of near-isogenic cotton lines (NILs), and to examine the use of the Cottonscope maturity distributions for breeder applications. Cottonscope measurements were performed on mature and immature fibers of varying days post-anthesis (DPA) from two pairs of NILs (MD 52ne versus MD 90ne; TM-1 versus the low maturity im). The patterns of cotton maturity and fineness during cotton fiber development of each NIL measured by the Cottonscope were compared to those measured by more conventional methods (e.g. the Advanced Fiber Information System (AFIS), an older and currently more widely used method). The Cottonscope maturity and fineness results were much more responsive to increasing DPA than the AFIS results, and the patterns of Cottonscope maturity values were consistent with those of the Fibronaire micronaire. Comparisons of the Cottonscope maturity distributions among the NILs demonstrated that the maturity distribution for im was very different and exhibited much lower maturity values compared to the distributions of other lines. The results demonstrated that the Cottonscope is an efficient instrument for cotton breeders to monitor fiber maturity and fineness of developing and mature cotton fibers.

An investigation on different parameters used for characterizing short cotton fibers

The quantity of short fibers in a cotton sample is an important cotton quality parameter. Short cotton fibers have detrimental impacts on yarn production performance and yarn quality. There are different parameters for characterizing the amount of short fibers in a cotton sample. The most widely used parameter is short fiber content (SFC). However, SFC has a significant shortcoming of very high measured variation. An investigation was carried out to compare the short fiber parameters to find a parameter that has lower variation and predicts yarn properties similarly as SFC does, including SFC defined at 0.5 inch length, SFC defined at 16 mm length, lower half mean length (LHML), floating fiber index (FFI), floating fiber percentage (FFP), and relative short fiber content (Rel. SFC). Based on our experimental data, we found that LHML had the lowest variation, was highly correlated with SFC, and predicted yarn properties similarly as SFC did. Therefore, LHML is a suitable alternative to short fiber content.

Cotton Wax and Its Relationship with Fiber and Yarn Properties

Skeins of yams spun from a wide range of cottons are dewaxed by Soxhlet extraction with ethanol. After drying, their mechanical properties are determined by single yarn tensile tests. Dewaxing produces a significant increase in yarn tenacity and a slight decrease in elongation at break. Yarn tensile properties are regressed on data sets of fiber properties that include wax content. Yarn strength is explained primarily by fiber strength and fiber fineness, although fiber strength and Micronaire value provided a reasonably good estimate. Wax content, which appears to be closely related to the specific surface area of the fiber, and hence Micronaire value, fails to qualify for entry into regression equations for yarn strength.