High-performance stretchable conductive fibers are desired for the development of stretchable electronic devices. Here we show a simple spinning method to prepare conductive hydrogel fibers with ordered polymer chain alignment that mimics the hierarchically organized structure of spider silk. The as-prepared sodium polyacrylate hydrogel fiber is further coated with a thin layer of polymethyl acrylate to form a core–shell water-resistant MAPAH fiber. Owing to the coexistence and reversible transformation of crystalline and amorphous domains in the fibers, MAPAH fibers exhibit high tensile strength, large stretchability and fast resilience from large strain. MAPAH fiber can serve as a highly stretchable wire with a conductive hydrogel core and an insulating cover. The stretchability and conductivity of the MAPAH fiber are retained at −35 °C, indicating its anti-freezing property. As a prime example of stretchable conductive fibers, MAPAH fibers will shed light on the design of next generation textile-based stretchable electronic devices.

Raw cotton may contain various kinds of trash, such as leaf, bark, and seed coat particles. The content of each of these trash categories is useful information for finding more efficient cleaning processes and predicting the quality of the finished products. This paper addresses the importance of using chromatic and geometric features of trash for trash description, and presents three different clustering methods that automatically classify trash based on the feature measurements. Compared with the geometric attributes of trash, such as size and shape, color attributes are less changeable during harvesting and ginning of cotton and are therefore more reliable and descriptive in categorizing trash. Three clustering methods—sum of squares, fuzzy, and neural network—prove effective for trash classification. Sum of squares clustering and fuzzy clustering require iterative computations and generate comparable classification accuracy. Neural network clustering yields the highest accuracy, but it needs more computational time for network training.

Extended breakage functions incorporating both single kernel size and moisture content were determined for First Break milling of hard and soft wheats under a sharp-to-sharp disposition. A moisture correction function was constructed by milling narrow size fractions of wheat tempered to different moisture contents, and subtracting the breakage function at a base moisture content of 16% from that at other moisture contents. The effect of adding moisture was to change an initially inverted U-shaped distribution at low moisture contents to a linear distribution at 16% moisture, then to a U-shaped distribution at higher moisture contents, reminiscent of the particle size distributions produced by dull-to-dull milling. The extended breakage functions were used to predict milling of unseparated feed samples at different roll gaps and moisture contents. In addition, mixtures of hard wheat at 14% moisture and soft wheat at 20% moisture, mixed in different proportions, were milled and the resulting particle size distributions compared with predictions. Excellent predictions were obtained in all cases. This con®rms the independent breakage of kernels during First Break milling, and demonstrates the potential of the breakage function approach for interpreting single kernel data in terms of predictions of milling performance.

Cereal Chem. 79(4):518-522Breakage of wheat kernels during first-break roller milling depends on many factors, including the disposition of the fluted rolls: sharp-to-sharp, sharp-to-dull, dull-to-sharp, or dull-to-dull. Wheat kernel breakage under different dispositions during milling was studied using high-speed video imaging. The results show significant slippage between kernels and the flutes when a dull working angle is used, especially when the dull angle is on the fast roll. Experiments were conducted to compare the size distributions resulting from the four dispositions. Representative hard and soft wheat cultivars were milled using fluted rolls at five different roll gaps, and the resulting size distribution of the milled stocks was measured by sieve analysis. A sharp-to-sharp disposition gave a relatively uniform or straight line size distribution over the particle size range of 212-2,000 mm. By contrast, a dull-to-dull disposition gave a Ushaped distribution with more larger and smaller particles and fewer in the middle size range. The size distributions from the other two dispositions lay between these, giving a transition from a straight-line distribution for sharp-to-sharp disposition, slightly U-shaped for sharpto-dull, more curved for dull-to-sharp, and highly U-shaped for dull-todull. The effect of roll gap was to change the balance between large and small particles.The particle size distribution resulting from first-break roller milling of wheat is of critical importance because it directly affects the mill flows and effectiveness of the rest of the milling process. A review of the literature by Fang and Campbell (2002) indicated that much research has been performed on various factors affecting first-break roller milling of wheat, including physicochemical properties of the wheat kernels and aspects of roll design and operation. However, relatively little work has addressed the effect of roll disposition on the breakage patterns of wheat kernels and the resulting particle size distribution delivered by first-break roller milling.In an accompanying article (Fang and Campbell 2002), we applied stress-strain analysis to identify the fracture mechanics principles describing wheat kernel breakage during milling with fluted rolls. By studying the deformation of a wheat kernel engaged between two fluted rolls in sharp-to-sharp (S-S) disposition, the planes of principal stresses and maximum shear stresses along which the kernel is most likely to be broken were calculated. As tensile strength is much smaller than compressive strength (Glenn et al 1991;Glenn and Johnston 1992), the most probable fracture plane was calculated to be that perpendicular to the principal tensile stress. The effects of roll gap, differential, and roll diameter on the stresses and strains were also discussed. High-speed video pictures of wheat kernel breakage under sharp-to-sharp milling were presented to illustrate the breakage patterns and fracture planes occurring during kernel breakage.

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The U.S. cotton classification system has been undergoing significant changes, moving from human classing to the use of precise instruments. Along with this trend, the current research is an effort to develop a new computer vision system to measure detailed trash and color attributes of raw cotton. The system primarily consists of a color ccd camera, xenon flash light, and customized software. In this paper, we introduce a new trash and spot identification method, multidimension thresholding, and the methods for characterizing size, spatial density, shape, and color of trash and spots present in cotton samples. We report on the trash and color measurements of twelve cotton samples, including statistical data and distribution curves, and we compare the results from this system with those from other instruments such as the Spinlab and Motion Control hvi machines and the Minolta Chroma Meter CR-210. Finally, we investigate the influence of trash and spots on cotton color values.