Micronaire Reading Research Articles

Measuring the Cross-Sectional Area of Cotton Fibers with an Image Analyzer

A procedure for measuring the cross-sectional areas of cotton fibers with an image analyzer was developed. The fibers were embedded with an ultra-low-viscosity . embedding medium and sectioned 1.5-μm thick; then the sections were stained with crystal violet. Measurement of 500 fibers per sample provided means that could be reproduced within ± 2.3%. Cross-sectional area was highly correlated with micronaire reading (r = 0.96).

Relation of Cotton Fiber Properties to Sliver Cohesion

A statistical evaluation was made of the relationship of certain fiber properties to cohesive force and coefficient of variation of cohesive force. Significant positive correlations were found between the cohesive force and fiber length, tenacity, and fiber yellowness (+b); negative correlations were found with fiber perimeter and reflectance (Rd). When length, colorimeter values, and Micronaire readings were used as independent variables in a stepwise regression program, 53% of the variation in the cohesive force could be explained by upper half mean length and Rd. The addition of other fiber properties whose measurement was influenced by fiber surface properties increased the explainable variation in the cohesive force to 71%.

Aerodynamic Drag of Cotton Fibers in Crossflow

“When a single cotton hair or fiber is exposed to a moving airstream, it experiences a fractional force induced by the relative movement of the air near the fiber surface. This force, known as aerodynamic drag, was measured for several cottons, each having a different Micronaire reading. Individual fibers were selected for fiber fineness and installed in a specially designed wind tunnel apparatus. Drag-force measurements for crossflow velocities from 12 to 280 cm/sec were recorded. Correlation of the test results show that aerodynamic drag coefficient for all cotton fibers can be expressed by the relation Cd = 10.35/Re0,825 for the 0.07 to 0.8 Reynolds number range, and Cd = 10.8/Re0,876 for the Reynolds numbers from 0.8 to 3. Laminar flow drag theories for smooth circular cylinders in crossflow are compared with the data recorded for cotton fibers.

Selection of Optimum Fiber Properties for Cotton Knits

The effects of fiber fineness, strength, and length on the properties of cotton and cotton/polyester blend knitting yarns and knitted fabrics were determined. Five cottons ranging from 3.9 to 5.2 in Micronaire reading, 38.1 g/tex to 48.1 g/tex in strength, and 31/32-in. to 1 1/8-in. staple length were evaluated. Yarns spun from a fine, medium-staple-length cotton were the most uniform, had the fewest imperfections, and compared favorably strengthwise with those spun from the strongest cotton. Differences in fiber properties had no significant effect on fabric abrasion or shrinkage resistance. However, fabrics produced from the high-strength cotton were the strongest both in the grey state and after resin finishing. Blending of 20% to 40% regular-tenacity polyester fiber with cotton reduced yarn strength, whereas similar blends using high-tenacity polyester resulted in increased yarn strength. Fabrics produced from the cotton/polyester blends generally had better abrasion resistance, less shrinkage, and smaller strength losses after resin treatment than the all-cotton fabrics.

Construction and Use of a Table for Converting the Arealometer Units A and D to Estimates of Width and Relative Wall Thickness of the Cotton Fiber

A table for converting Arealometer A and D readings to estimates of average fiber width (F) in micrometers and relative wall thickness (RWT) in percent is presented. The table gives “clean” estimates of F and RWT that are not obtained from A and D considered separately nor from Micronaire readings. It can be used to obtain information on the fiber properties of the large collection of cotton breeders' stocks for which Arealometer data have been recorded. A survey of over one thousand such stocks indicates that fine, medium-length fibers with relatively thick walls—a combination that may be desirable for open-end spinning—are characterized by high A and low D Arealometer readings. It is a rare combination in Upland cottons but is available in primitive forms of G. hirsutum L. and G. barbadense L. Whether this combination can be transferred to Upland cottons without reducing yield potential remains an open question.

Effects of Narrow Row, Plant Population, and Nitrogen Application on Cotton Fiber Characteristics1

AbstractNarrow row cotton (Gossypium hirsutum L.) has shown the potential for earlier maturity. This is especially significant in areas where season length is marginal. The effect of narrow row plantings has been similar to a reduced N application rate.Studies were conducted on a Teller fine sandy loam (fine‐loamy, mixed, thermic, Udic Argiustolls) to relate the effects of N rates (0, 45, and 90 kg/ha), row spacing (25, 51, and 76 cm), and plant population (123,550 and 173,000 plants/ha) on cotton fiber characteristics. The effects of N‐row spacing and N‐population interactions were apparent. Finer fiber (decreased micronaire) resulted from high N with 25‐cm row width or high N and high population. But where no N as is applied, the 25‐cm row width produced coarser fibers. There were significant positive correlations between micronaire readings and lint and seed yields in both years.N effects on uniformity index varied from year to year. Uniformity index tended to decrease for 25‐cm row width as plant population increased and at the low plant population as row spacing increased from 25 to 76 cm. In both years there were significant correlations between uniformity index and percent pulled lint, and between uniformity index and fiber fineness.Increasing row spacing without increasing plant population, and vice versa, led to significantly lower fiber strength by 0‐inch gauge measurements in 1973. However, increasing row spacing from 25 to 76 cm produced a significant increase in fiber strength in 1974 by the 1/8‐in. gauge measurement. Fiber strength was negatively correlated with yield in 1974.The major fiber properties of length, strength, and fineness were not consistently affected by the variables of N, row spacing, and population. Some of the interacting effects are of special interest and deserve further evaluation so that the influence of climatic differences can be placed in perspective in relation to the treatment variables.

Relationship of Yield, Seed Quality, and Fiber Properties in Upland Cotton1

Seed and fiber samples of four Upland cotton (Cossypium hirsutum L.) cultivars, grown at 17 locations in the 1973 Regional Cotton Variety Test, were examined for yield, seed quality, and fiber quality. Correlation coefficients were calculated among eight agronomic and quality parameters.No significant correlations were found between yield and oil content or yield and protein content. Three of the cultivars showed positive correlations between oil content and fiber maturity and negative correlations between oil content and percent immature seed. The strongest correlation for protein was a negative relationship with fiber maturity. ‘Lockett 4789A’ gave a high positive correlation between oil content and seed index. ‘Acala 1517–70’ showed a strong negative relationship between protein and fiber maturity. Both of these cultivars showed positive correlations between yield and fiber strength.The feasibility of using Micronaire readings (fiber maturity) as indicators of oil content for cottonseed in the various production zones are discussed.

An Analysis of Carding Efficiency and Processing Performance of Cotton /Polyester Blends

The effect of various levels of cotton and polyester fibers blended during opening and picking on carding efficiency and processing performance was investigated. The cotton was middling grade, 1 1/16-in. staple length, and 4.2 micronaire reading; the polyester was high modulus, 1.5 in. long, and 1.5 denier. As the percent polyester in the blend increased, compression recovery increased moderately and shear friction appreciably. The increase in friction offset the increase in compression recovery so that cylinder load, fiber hooks, and card sliver variability increased with greater polyester content. However, as the polyester content increased, the increase in fiber friction and length uniformity improved drafting efficiency so that second drawing sliver and yarn uniformity improved. Increasing the polyester content of a blend did not improve yarn grade; high cotton content blends had the same grade as high polyester content blends. At constant end breakage, production in spinning increased rapidly to a 65c/35p blend; additional increases in polyster resulted in only slight improvements in spinning efficiency. Very little polyester was lost in the carding waste even with close flat-to-cylinder settings (0.010 in.), which no doubt provided better carding action on the cotton component in the blend than do settings commonly used. However, it is possible that this close a setting for high percentage polyester blends might cause excessive cylinder loading under mill conditions.

Effect of Mixing Cottons Differing in Micronaire Reading and Carding Variables on Cotton Sliver Quality, Yarn Properties, and End Breakage

Three cotton blends of average micronaire reading but composed of various percentages of high, low, and average micronaire reading cottons were carded into three sliver weights at each of three levels of card production rates. The effect of blend, sliver weight, card production rate, and Hat speed on card loading, card waste, sliver uniformity, fiber orientation, and processing performance were observed.

The Effect of Fallowing Obtained with Skip‐Row Culture on Verticillium Wilt of Cotton

AbstractSkip‐row production of cotton (Gossypium hirsutum L.), plant‐4‐rows‐skip‐4‐rows, permits clean fallowing of the nonplanted rows. The fallow obtained from this cultural practice was effective in reducing Verticillium wilt (Verticillium dalhiae Kelb.) incidence, increasing yield, and improving fiber and seed quality. Irrespective of cultivar used during the 2‐year study, cotton produced on plots fallowed for one season produced longer fiber with a higher micronaire reading. Seed quality was also improved in the single test where this variable was evaluated. Following a year of fallow, the onset of Verticillium wilt was delayed, it developed at a slower rate, and total wilt incidence was lower.

Evaluation of Fiber Properties of Single Cotton Plants as Related to Yarn Strength

The present base of selecting single cotton plants in U.A.R. due to micronaire reading and Pressley index was evaluated. About 300 plants in each of Giza 68, Giza 67, and Giza 66 newly released cotton varieties were tested for fiber properties. Samples having the same fiber length, micronaire reading, and tenacity were blended together to form composite samples for spinning on the Shirley miniature plant. The Stelometer at 1/8-in. gauge length gave the highest r values with other properties and instruments. The same measure of tenacity gave the highest value of r with lea product. The positive cor relation coefficients between micronaire reading or tenacity and lea product were gradually increased towards longer fibered categories. This emphasized the role of fiber length in attaining stronger yarns from individuals of higher tenacity and/or micronaire reading.

Correlation Studies Between Grade, Fiber Properties, and Yarn Strength in Egyptian Cotton

Fibrograph measurements were found to correlate better with grade and yarn strength as compared with Balls sorter measurements. Fineness and maturity combined expressed by the micronaire reading was highly correlated with grade than either fineness or maturity measured separately. A high-correlation coefficient was obtained between grade and tenacity measured by Stelometer at 1/8-in. gauge length.

Effects of Blends of Medium-Staple Low and High Micronaire Reading Cottons, Sliver Weight, and Carding Rate on Card Loading, Sliver Quality, and Processing Performance

This study determines the effect of such carding parameters as sliver weight, doffer speed, and carding rate on cylinder loading, card sliver quality, and waste removal on the processing performance of three blends composed of various per centages of low, average, and high micronaire reading cottons, blended to obtain a constant average micronaire reading of the mix. Blend composition, sliver weight, and carding rate had no significant effect on yarn skein strength, uniformity, and elongation. High carding rates decreased long-term card-sliver variability and increased card sliver short-term varia bility; increased yarn imperfections appreciably and decreased yarn grade slightly. At high carding rates, a blend con taining 30% of low and 70% of high micronaire reading cottons resulted in a greater cylinder load and lower fiber transfer than the other two blends containing various percentages of average micronaire reading cotton. This blend also had higher fiber breakage at high carding rates and slightly higher end breakages in spinning. Compared with light-weight card sliver, heavy card sliver increased cylinder load, majority hooks, yarn irregularity, and imperfections and decreased the cleaning efficiency of the card. More fibers and less actual waste were removed than when producing a light-weight card sliver.

Some Relationships of Cotton Micronaire Reading and Carding Parameters to Card Loading, Sliver Quailty, and Processing Performance

Some Relationships of Cotton Micronaire Reading and Carding Parameters to Card Loading, Sliver Quailty, and Processing Performance

Sonic and Ultrasonic Irradiation of Cotton Fibers

An investigation was made of the effects of exposure to sonic and ultrasonic energy on the physical and chemical properties of Deltapine and Acala 4-42 cotton irradiated in partially degassed water. From the results of more than 1300 different tests, it appears that some of the cotton fibers properties can be modified. However, the main changes observed to date appear to be of a physical and not of a chemical nature. Cavitation, specially vaporous cavitation, has been singled out as the main factor responsible for fibers modification. Frequency and acoustic energy density in the liquid phase play a key role only because they indirectly control the intensity of cavitation phenomena. The importance of sample size for uniform irradiation has also been stressed. Irradia tion around 30 kcps with an energy density of 20 watts/liter and a cavitation activity of 220 cavits lead to strong fiber surface modifications and fibers entanglement after a few hours of insonation. Evidence of severe fibrillation has been established not only by optical and electron microscopic techniques but also through alkali swelling tests and Micronaire readings. Generally speaking the Deltapine variety of cotton grown under conditions of natural rainfall seems slightly more susceptible to cavitation effects than Acala 4-42 grown under irrigated conditions. It has also been clearly established that contrary to nonirradiated fibers, ultrasonically treated cotton enables to make paper sheets of acceptable tensile strength. From both the theoretical and experimental viewpoint a rather promising avenue seems to have been opened for future large scale ultrasonic fibrillating of fibers suspension. On the negative side we must mention that due to absorption phenomena high-power sonic irradiation does not seem a very promising tool for trash removal from raw cotton.

The Effect of Fiber-Bundle Elongation of Medium Staple Cottons on Processing Performance and Y arn Properties

Cottons differing in fiber-bundle elongation (5.8%, 7.3%, and 10.1%) were processed into 30/1 (20 tex) and 40/1 (15 tex) yarns at two levels of twist (3.75 T. M. and 4.50 T.M.) and of spinning draft (27.5 and 40.0). Fiber elongation had no effect on nep potential or uniformity of slivers. No relation was found between fiber-bundle elonga tion, 2.5% span length and fiber strength measured at " gage length, and only a general inverse trend was found with Micronaire reading. The reduction in fiber hooks when the cottons differing in elongation were processed from card sliver into second drawing sliver was significantly lower for the high- than for the low-elongation cotton. The higher-elongation cotton spun with fewer ends down than the lower-elongation cotton with this effect being more,pronounced at higher drafts and spindle speeds, lower twists, and as the yarn became finer. Generally, an increase in fiber elongation from 6% to 10% made possible a spindle speed increase of about 1000 rpm for the high twist 30/1 and 40/1 yarns at constant end breakage rate. In practical terms, it appears that the overall effect of fiber elongation (low to high) was approximately twice that of draft and about two-thirds that of twist and yarn number. It was possible to use higher spindle speeds without increasing end breakage with a tougher fiber and with a fiber of lower average tensile stiffness. Fiber average tensile stiffness and toughness were linearly and directly correlated with their yarn counterparts. Single-strand yarn strength and yarn elongation were linearly related to fiber elongation, with increased fiber elonga tion resulting in increased yarn strength and elongation.

Measuring Fiber Fineness by Horizontal Air-Flow

An apparatus to measure fiber-fineness by horizontal air-flow has been devised. Several specimens were measured with this apparatus, and the results have been compared with theory.The comparison has shown that:(1) The apparatus can measure the weight-fineness of each single fiber, irrespective of the fiber-length or the kind of raw cotton used.(2) Using the correction coefficient inherent in the apparatus brings an experimental value into good agreement with theory.(3) The experimental error is about ±0.1 on micronaire reading for fineness below 4. For fineness above 4, the error is slightly larger.

An Evaluation of the SRRL Non-Lint Tester for Determining the Trash Content of Lint Cotton

The SRRL Non-Lint Tester, a new machine for determining the non-lint content of lint cotton, was evaluated on more than 1000 lots of cotton representing a wide range of grades, classer's lengths, and fiber properties. Comparison of the results from the Tester with those from the ASTM method that uses the Shirley Analyzer shows a correlation coefficient of 0.90 between the two machines. An analysts of results from both machmes shows that the non-lint content of cotton is affected to a significant degree by grade, classer's length and Micronaire reading. It was found that non-lint content values from the Slurley Analyzer were consistently higher than those from the Tester, and the Tester values for rephcated samples were consistently less variable than those from the Analyzer. Both machines appear to estimate reliably the non-lint content of cotton, with the tester being about 10 times faster.

The Effect of Blending Cottons of Dissimilar Fiber Properties upon Spinning Performance and Yarn Quality

The blending of cottons with dissimilar fiber properties has been investigated to determine its effect upon processing performance, spinning performance and yarn quality in medium and fine count yarns. In these trials, the effect of grade and cavitomic damage (SM and LM, Sp.), fiber fineness (3.4 and 5.5 Micronaire reading), staple length (1/8 in. and 1 1/16 in.) and fiber strength (70,000 lb./in. 2 and 95,000 lb./in.2) was evaluated. Cotton bales differing appreciably in the property being investigated but having other pertinent properties similar were used. For each trial, the 100% components of the property being investigated and three blends of these cottons were run. The effects of varying percentages of the different cotton fiber properties upon spinning performance and yarn quality are shown.

Cotton Fiber Maturity and Fineness: Both Predicted Separately, Accurately, and Rapidly

Both Causticaire fineness and Causticaire maturity of cotton fibers can be predicted separately, yet simultaneously, accurately, and rapidly. Only Micronaire readings, a conversion table, and the varietal identity are necessary for accurate predictions.