79 resultados para Fiber coil


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Fibers growing, branching, and bundling are essential for the development of crystalline fiber networks of molecular gels. In this work, for two typical crystalline fiber networks, i.e. the network of spherulitic domains and the interconnected fibers network, related kinetic information is obtained using dynamic rheological measurements and analysis in terms of the Avrami theory. In combination with microstructure characterizations, we establish the correlation of the Avrami derived kinetic parameter not only with the nucleation nature and growth dimensionality of fibers and branches, but also with the fiber bundles induced by fiber-fiber interactions. Our study highlights the advantage of simple dynamic rheological measurements over other spectroscopic methods used in previous studies for providing more kinetic information on fiber-fiber interactions, enabling the Avrami analyses to extract distinct kinetic features not only for fibers growing and branching, but also for bundling in the creation of strong interconnected fibers networks. This work may be helpful for the implementation of precise kinetic control of crystalline fiber network formations for achieving desirable microstructures and rheological properties for advanced applications of gel materials. This journal is © the Partner Organisations 2014.

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Previous investigations have shown that prickle discomfort sensations of wool fabrics are primarily determined by the mean fiber diameter of the wool. It is also known that differences in wool fiber curvature (crimp) affect softness of handle of greasy wool and of wool textiles. In a replicated experiment, we investigated if wearers could detect the effect of using 17 µm superfine wool of low (74°/mm) or high (114°/mm) fiber curvature, and when the wools were blended with 17 µm cashmere (fiber curvature 49°/mm) in differing proportions, on four comfort sensations. Eight single jersey knitted fabrics were assessed under a controlled protocol using forearm sleeves made of the test fabric and a control fabric. Data (37 sensorial assessments of high curvature wool fabrics; 38 sensorial assessments of low curvature wool fabrics) were analyzed using linear mixed model analysis (restricted maximum likelihood), which included fixed effects for wool type and blend ratio and a random effect for participant. The use of a control sleeve fabric reduced variance due to participant effects by providing an anchor for each sensation over time. Wool fiber curvature affected participant assessment of breathability, comfort, feel after exercise (damp/dry) and skin feel (prickly/soft), with preferred values associated with high curvature (crimp) superfine wool. Increasing the proportion of cashmere in fabrics increased skin feel (better assessed softness). Skin feel was strongly associated with the evaluation of the fabrics by the Wool ComfortMeter and with increasing hairiness of yarns.

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This study investigated the relationships between the sensations of sweaty, damp, muggy and clingy, as assessed by human response from wearer trial garment assessment, and fiber type, fiber, yarn and fabric properties and instrumental fabric measurements of next-to-skin knitwear. Wearer trial assessment of 48 fabrics followed a strict 60 minute protocol including a range of environmental conditions and levels of exercise. Adjusted mean weighted scores were determined using linked garments. Instrumental fabric handle measurements were determined with the Wool HandleMeter (WHM) and Wool ComfortMeter. Data were analyzed using forward stepwise general linear modeling. Mean fiber diameter (MFD) affected the sweaty, damp, muggy and clingy sensation responses accounting for between 23.5% and 56.2% of the variance of these sensations. In all cases, finer fibers were associated with lower sensation scores (preferred). There were also effects of fiber type upon sweaty, muggy and clingy scores, with polyester fiber fabrics having higher scores (less preferred) compared with fabrics composed of wool, particularly for peak sweaty scores in hot and active environments. Attributes such as fabric density, yarn linear density, knitting structure and finishing treatments, but not fabric thickness, accounted for some further variance in these attributes once MFD had been taken into account. This is explained as finer fibers have a greater surface area for any given mass of fiber and so finer fibers can act as a more effective sink for moisture compared with coarser fibers. No fabric handle parameter or other attribute of fiber diameter distribution was significant in affecting these sensation scores.

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A novel fibrous conduit consisting of well-aligned nanofibers with longitudinal nanogrooves on the fiber surface was prepared by electrospinning and was subjected to an in vivo nerve regeneration study on rats using a sciatic nerve injury model. For comparison, a fibrous conduit having a similar fiber alignment structure without surface groove and an autograft were also conducted in the same test. The electrophysiological, walking track, gastrocnemius muscle, triple-immunofluorescence, and immunohistological analyses indicated that grooved fibers effectively improved sciatic nerve regeneration. This is mainly attributed to the highly ordered secondary structure formed by surface grooves and an increase in the specific surface area. Fibrous conduits made of longitudinally aligned nanofibers with longitudinal nanogrooves on the fiber surface may offer a new nerve guidance conduit for peripheral nerve repair and regeneration.