Wet-spinning of multifunctional graphene fibers using graphene oxide liquid crystals

The recent discovery of liquid crystalline (LC) behavior of graphene oxide (GO) dispersions in various organic, and aqueous media brings added control to the assembly of larger structures using the chemical process approach.[1-3] The LC state can be used to direct the ordered assembly of nanocomponents in macroscopic structures via simple methods like wet-spinning. [3] Here, we developed a scaleable fabrication route to produce graphene fibers via a facile continuoes wetspinning methode. We develop solid understanding in the required criteria to correlate processability with LC behavior, aspect ratio and the dispersion concentration to provide a viable platform for spinning of LC GO. We demonstrate a striking result that highlits the importance of GO sheet size and polydispersity in generating wetspinnable LC GO dispersions from very low spinning dope concentrations (as low as 0.075 wt. %). The new knowledge gained through rheological investigations provides a sound explanation as to why continuous spinning of binder-free GO fibers is enabled by the LC behavior at this very low concentration.

Intelligent animal fiber classification with artificial neural networks

Artificial neural networks (ANN) are increasingly used to solve many problems related to pattern recognition and object classification. In this paper, we report on a study using artificial neural networks to classify two kinds of animal fibers: merino and mohair. We have developed two different models, one extracting nine scale parameters with image processing, and the other using an unsupervised artificial neural network to extract features automatically, which are determined in accordance with the complexity of the scale structure and the accuracy of the model. Although the first model can achieve higher accuracy, it requires more effort for image processing and more prior knowledge, since the accuracy of the ANN largely depends on the parameters selected. The second model is more robust than the first, since only raw images are used. Because only ordinary optical images taken with a microscope are employed, we can use the approach for many textile applications without expensive equipment such as scanning electron microscopy.

An experimental examination of fiber reinforcing effect with a novel composite specimen

This paper introduces a simple fiber/tape composite that is easy to prepare and structurally more uniform. This novel composite provides a good alternative standard composite sample for experimental study of various phenomena and issues in fiber reinforced composite behaviors. Experimental results in the present work demonstrate how the fiber fragmentation, fiber-reinforcing effect and the gauge length effect can be successfully evaluated by using this novel composite specimen.

Reducing yarn hairiness with a modified yarn path in worsted ring spinning

The spinning geometry of a ring frame plays an important role, and the twist triangle is the critical region in ring spinning. Changes in the spinning geometry may affect yarn properties. This paper examines the idea of ring spinning with a "diagonal" yarn path, and the effect of such a path on yam properties, particularly hairiness. Both "left diagonal" and "right diagonal" yam arrangements are tried on a 24-spindle Cognetex FLC worsted ring frame. The hairiness results obtained from the Zweigle hairiness meter show that the right diagonal yam path produces yams of lower hairiness than the conventional ring spun yarn in almost all the hair length groups. Yam evenness and tenacity are not as sensitive to the change in yarn path. The mean spindle speed at break is also tested, and there is some deterioration in spinning efficiency with the right diagonal yarn path, particularly at higher spinning speeds. Results from this study may help explain variations in yarns spun on poorly aligned ring frames.

Dietary regulation of fat oxidative gene expression in different skeletal musle fiber types

Objective: To determine the effect of a high-fat diet on the expression of genes important for fat oxidation, the protein abundance of the transcription factors peroxisome proliferator-activated receptor (PPAR) isoforms α and γ, and selected enzyme activities in type I and II skeletal muscle. Research Methods and Procedures: Sprague-Dawley rats consumed either a high-fat (HF: 78% energy, n = 8) or high-carbohydrate (64% energy, n = 8) diet for 8 weeks while remaining sedentary. Results: The expression of genes important for fat oxidation tended to increase in both type I (soleus) and type II (extensor digitorum longus) fiber types after an HF dietary intervention. However, the expression of muscle type carnitine palmitoyltransferase I was not increased in extensor digitorum longus. Analysis of the gene expression of both peroxisome proliferator-activated receptor-γ coactivator and forkhead transcription factor O1 demonstrated no alteration in response to the HF diet. Similarly, PPARα and PPARγ protein levels were also not altered by the HF diet. Discussion: An HF diet increased the expression of an array of genes involved in lipid metabolism, with only subtle differences evident in the response within differing skeletal muscle fiber types. Despite changes in gene expression, there were no effects of diet on peroxisome proliferator-activated receptor-gamma coactivator and forkhead transcription factor O1 mRNA and the protein abundance of PPARα and PPARγ.

Minimizing energy consumption of yarn winding in ring spinning

Ring spinning has been and will continue to be an important system for making staple yarns from different fibers in the textile industry. But high power consumption and low productivity remain the two outstanding problems with ring spinning. Based on an analysis of power distribution during yarn winding in ring spinning, models for the ratio of energy consumption to yarn production over a full yarn package are established. Spindle speed, yarn count, and package diameter are the three key parameters affecting this ratio. The effects on energy consumption of these parameters are discussed through a case study. The energy-to-production ratio increases with increased package diameter but decreases with increased spindle speed and/or yarn count (tex). The results will help guide spinners in minimizing energy consumption in ring spinning.

Compressive and flexural properties of hemp fiber reinforced concrete

The compressive and flexural properties of hemp fiber reinforced concretes (FRC) were examined in this paper. Natural hemp fiber was mixed using dry and wet mixing methods to fabricate the FRC. Mechanical properties of the FRC were investigated. The main factors affecting compressive and flexural properties of the FRC materials were evaluated with an orthogonal test design. Fiber content by weight has the largest effect. The method for casting hemp FRC has been optimised. Under the optimum conditions, compressive strength increased by 4 %, flexural strength increased by 9 %, flexural toughness increased by 144 %, and flexural toughness index increased by 214 %.

Distribution of power requirements during yarn winding in ring spinning

A model of a yam package is established for a ring spinning system. The yarn layer, surface area, and mass of the yam package are formulated with respect to the diameters of the empty bobbin and full yarn package, yarn count, and yarn winding-on time. Based on the principles of dynamics and aerodynamics, models of the power requirements for overcoming the skin friction drag, increasing the kinetic energy of the yarn package (bobbin and wound yarn), and overcoming the yarn wind-on tension are developed. The skin friction coefficient on the surface of a rotating yam package is obtained from experiment. The power distribution during yam packaging is discussed based on a case study. The results indicate that overcoming the skin friction drag during yarn winding consumes the largest amount of energy. The energy required to overcome the yarn wind-on tension is also significant.

Skin friction coefficient on a yarn package surface in ring spinning

The skin friction coefficient on the surface of a rotating yarn package affects the power required to drive the package. This paper examines the relationship between the skin friction coefficient on the package surface and its diameter and rotating speed, based on the fundamentals of aerodynamics and the experimental results of power consumption. Skin friction coefficients on the surfaces of an airplane, car top, and yarn package are discussed. The results indicate that the skin friction coefficient on the package surface without hairiness depends on the package diameter and spindle speed only. The skin friction coefficient on the yarn package surface is about three times that on the top surface of a car, and is about twenty times that on an airplane surface. The power consumed to overcome skin friction drag is more than that consumed to drive the spindle if the spindle speed is very slow. However, the situation reverses when the spindle speed is fast.

Modeling the tensile behavior of fiber bundles with irregular constituent fibers

In this paper, the effect of fiber dimensional irregularities on the tensile behavior of fiber bundles is modeled, using the finite element method (FEM). Fiber dimensional irregularities are simulated with sine waves of different magnitude. The specific stress-strain curves of fiber bundles and the constituent single fibers are obtained and compared. The results indicate that fiber diameter irregularity along fiber length has a significant effect on the tensile behavior of the fiber bundle. For a bundle of uniform fibers of different diameters, all constituent fibers will break simultaneously regardless of the fiber diameter. Similarly, if fibers within a bundle have the same pattern and level of diameter irregularity along fiber length, the fibers will break at the same time also regardless of the difference in average diameter of each fiber. In these cases, the specific stress and strain curve for the bundle overlaps with that of the constituent fibers. When the fiber bundle consists of single fibers with different levels of diameter irregularity, the specific stress-strain and load-elongation curves of the fiber bundle exhibit a stepped or “ladder” shape. The fiber with the highest irregularity breaks first, even when the thinnest section of the fiber is still coarser than the diameter of a very thin but uniform fiber in the bundle. This study suggests that fiber diameter irregularity along fiber length is a more important factor than the fiber diameter itself in determining the tensile behavior of a fiber bundle consisting of irregular fibers.

Effects of bleaching and dyeing on the quality of alpaca tops and yarns

This paper reports the effects of bleaching of alpaca tops and dyeing of bleached alpaca tops/yarns on the quality of tops and yarns. A dark brown alpaca top was bleached with hydrogen peroxide. Two bleaching methods were tried for effectiveness of color removal. A portion of each bleached top was dyed after bleaching. Color parameters were examined for unbleached, bleached and bleached/dyed tops, these tops were then converted into yarns of different twist levels and counts using a worsted spinning system. Some of the bleached yarn from each bleaching method was dyed in a package dye vat to compare the difference of top dyeing versus yarn package dyeing on yarn quality. Fiber diameter, yarn strength, yarn evenness, yarn hairiness and fiber degradation were tested to examine the effects of bleaching and dyeing on these properties at top and yarn stages. A processing route for bleaching and dyeing alpaca fiber was recommended.

Lupin kernel fiber consumption modifies fecal microbiota in healthy men as determined by rRNA gene flourescent in situ by hybridization

Background Changes in the composition of gastrointestinal microbiota by dietary interventions using pro- and prebiotics provide opportunity for improving health and preventing disease. However, the capacity of lupin kernel fiber (LKFibre), a novel legume-derived food ingredient, to act as a prebiotic and modulate the colonic microbiota in humans needed investigation.

Aim of the study The present study aimed to determine the effect of LKFibre on human intestinal microbiota by quantitative fluorescent in situ hybridization (FISH) analysis.

Design A total of 18 free-living healthy males between the ages of 24 and 64 years consumed a control diet and a LKFibre diet (containing an additional 17–30 g/day fiber beyond that of the control—incorporated into daily food items) for 28 days with a 28-day washout period in a single-blind, randomized, crossover dietary intervention design.
Methods Fecal samples were collected for 3 days towards the end of each diet and microbial populations analyzed by FISH analysis using 16S rRNA gene-based oligonucleotide probes targeting total and predominant microbial populations.

Results Significantly higher levels of Bifidobacterium spp. (P = 0.001) and significantly lower levels of the clostridia group of C. ramosum, C. spiroforme and C. cocleatum (P = 0.039) were observed on the LKFibre diet compared with the control. No significant differences between the LKFibre and the control diet were observed for total bacteria, Lactobacillus spp., the Eubacterium spp., the C. histolyticum/C. lituseburense group and the Bacteroides–Prevotella group.
Conclusions Ingestion of LKFibre stimulated colonic bifidobacteria growth, which suggests that this dietary fiber may be considered as a prebiotic and may beneficially contribute to colon health.

An investigation of yarn snarling and balloon flutter instabilities in ring spinning

This article reports theoretical and experimental investigation on yarn snarling and balloon fluttering in ring spinning. Yarn snarling and balloon fluttering affect yarn breakage in ring spinning. The theoretical model has incorporated the tangential component of air drag on a ballooning yarn, which was ignored in previous models. The results show that yarn snarling happens in the balloon when the ratio of yarn length in the balloon to balloon height is greater than a specific value that depends on the yarn type and count. Yarn tension experiences an obvious change before and after yarn snarling. The balloon flutter appears between normal balloons while the balloon loops are changing. Fluttering balloon shapes that oscillate periodically between two and three loop configurations as yarn tension varies periodically have also been observed experimentally.

The hairiness of worsted wool and cashmere yarns and the impact of fiber curvature on hairiness

In this study, a range of carefully selected wool and cashmere yarns as well as their blends were used to examine the effects of fiber curvature and blend ratio on yarn hairiness. The results indicate that yarns spun from wool fibers with a higher curvature have lower yarn hairiness than yarns spun from similar wool of a lower curvature. For blend yarns made from wool and cashmere of similar diameter, yarn hairiness increases with the increase in the cashmere content in the yarn. This is probably due to the presence of increased proportion of the shorter cashmere fibers in the surface regions of the yarn, leading to increased yarn hairiness. A modified hairiness composition model is used to explain these results and the likely origin of leading and trailing hairs. This model highlights the importance of yarn surface composition on yarn hairiness.