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To study the adsorption to pure oil and oil-water mixture, cattail fiber waddings with different fibers, wadding structures, blending ratios were prepared. Oil absorbencies in the pure oils and oil-water mixtures were tested and evaluated. The analysis showed that cattail fiber waddings have better adsorption performance to pure oil and oil-water mixture, which is higher than 20 g/g. The retention rate of pure oil is higher than 90%, while retention rate of oil-water mixture decreases to 68%. With the increase of wadding thickness and cattail ratio, the oil adsorption and retention of composite waddings are heightened. The oil-retention declines with the blending of polypropylene (PP) fiber. The oil adsorption of kapok fiber is better than that of cattail fiber and PP fiber. Therefore, oil adsorption performance is improved through adjusting the fiber ratio and porous structure.

To study the frequency response characteristics of knitted fabric-based frequency selective surface (FSS), high-pass knitted fabric-based FSS were designed and prepared. The electromagnetic transmission characteristics were tested in a microwave anechoic chamber. The results show that weft-knitted fabric based FSS has high-pass and low-resistance electromagnetic properties. When the placement direction of the knitted fabrics and the polarization mode of electromagnetic wave are different, the frequency response characteristics are distinct. When the ratio of conductive yarns increases, the electromagnetic wave shield ability and breathability of knitted fabric based FSS are enhanced. The shielding ability of the fabric increases with the density, but the permeability of the fabric decreases. As the incident angle of electromagnetic wave increases, the electromagnetic wave component entering the fabric decreases, and the electromagnetic wave passing through the fabric decreases. Therefore, under the premise of wear comfort, the frequency response characteristics of knitted fabrics can be controlled and selective transmission of electromagnetic wave can be achieved by designing the structure and weaving parameters of knitted fabrics and adjusting the polarization mode and incidence angle of electromagnetic wave.

In this paper, a novel kind of electromagnetic (EM) functional textiles is proposed, which show high-pass characteristics as they interact with EM waves. The periodically conductive woven fabric was designed, fabricated, and measured. Specifically, by means of unit cell model building and EM simulation, the theoretical S21 (transmission coefficient) and S11 (reflection coefficient) curves were obtained. A concrete sample was fabricated through weaving process, and its transmission characteristics were measured in the microwave anechoic chamber. The measured and simulated results were highly consistent, demonstrating the validity of design process. Compared with the aluminum foil paper sample, the S21 values of fabricated sample were a little smaller, and the reason could be attributed to yarn crimp and surface roughness. The EM characteristics of fabricated sample under two different polarization modes were slightly different, which was due to the beating-up tension of weaving process. The work could offer new research ideas, and the related products have potential advantages over rigid plates on the account of textile characteristics.

In order to explore the electromagnetic transmission performance of frequency selective fabrics (FSFs) with fractal units, six samples of Y-shaped fractal parameters with different sizes were prepared by computer embroidery technology, and tested using anechoic chamber test method. The effects of unit type, polarization mode, incident angle and unit size parameters on the transmission performance of different samples were respectively analyzed in depth. The results show that for the aperture type and patch type FSFs, the incident angle has a certain influence. When the incident angle of the two groups of samples is 0°, the resonance peak is the largest. When the incident angle increases to 45°, there are two resonance peaks of different amplitudes in the range of 4 GHz ∼ 20 GHz. The size and spacing of the unit pattern have both visible effects on the transmission coefficient, but the former has a greater impact on the transmission coefficient. There is a certain tension and contraction between the base fabrics during the preparation of the flexible FSFs, which are controlled to make the sample size more accurate. In addition, in order to reduce the calculation time and improve the design efficiency, two kinds of patch type and aperture type with the same size were simulated and optimized using HFSS algorithm. Comparison of measured and simulated results verify the effectiveness of simulation design. [ABSTRACT FROM AUTHOR]

To study the frequency response characteristics of high-pass woven fabric, samples with varying conductive grid structure, structure parameters, material conductivity, and electromagnetic (EM) wave parameters were prepared and measured by the shielding room method. Experimental results showed that conductive grid structure was effective in obtaining bidirectional shielding ability and conductive stripe structure had directional shielding property to the EM wave.. Depending on changing the ratios of dielectric and conductive yarns, structure parameters exerted influences on frequency response characteristics by affecting vertical inductances and horizontal capacities in the equivalent circuit. High-pass woven fabric with high-conductivity yarns could possess stronger shielding ability. Due to the different compactness in weft and warp directions after weaving, bidirectional grid structure fabrics showed distinct polarization selective characteristic as well as unidirectional structure fabric. When the incident angle of the EM wave increased, the incident component decreased and the transmittance became unstable. The experimental results were discussed in-depthbased on mechanism analysis, which could provide reference to the relevant research. [ABSTRACT FROM AUTHOR]

Asymmetrical Y-shaped and Y-ring-shaped frequency selective fabrics ( FSFs) were proposed in this paper. They were prepared by computer engraving technology and tested in the anechoic chamber by using the free-space method. The test results of representative samples show that the resonance frequencies and the resonance peak or valley values in two polarization modes are not completely identical but the differentials are small, indicating that the influences of polarization modes are not significant. The transmission coefficient curves of Y-shaped and Y-ring-shaped FSFs with various size parameters are obviously different. For instance, as the unit size D increases by 4. 0 mm, the resonance frequencies of patch FSFs decrease by 1. 92 GHz and the resonance valleys increase by 12. 32 dB. Different size parameters have dissimilar effects on the transmission characteristics and the corresponding influence laws should be analyzed concretely. The work could provide reference for the structural design and characteristics analysis of other FSFs. [ABSTRACT FROM AUTHOR]

To make full use of the resource-rich domestic kapok fiber and turn waste into wealth, the kapok fruit, fiber morphology and oil sorption abilities of Quanzhou kapok were studied in comparison with Indonesia kapok. Comparing to Indonesia kapok, Quanzhou kapok has the similar fruit shape and internal structure. The fiber length of Quanzhou kapok is concentrated in 14.5-27.5 mm which is slightly shorter than Indonesia kapok fiber, but the length distribution is more uniform; the fiber fineness centers around 15-35 µm. Epidermis wax mass fraction of Quanzhou kapok fiber was about 1.660%. The average oil sorption capacity of Quanzhou kapok fiber assembly in soybean oil is 41.05 and the average retention rate is 97.48%. The average oil sorption capacity and retention rate in engine oil is 37.85 and 97.97% respectively, higher than that of Indonesia kapok. Kapok fiber assembly could be recirculated fewer than SIC Times for better oil-absorption. The result show that Quanzhou kapok fiber has more excellent oil-absorption ability and can be used as oil-sorbing material. [ABSTRACT FROM AUTHOR]

In order to reduce the fiber diameter and the energy consumption in the meltblowing process, a modified slot die with two blocks was designed in this article. The numerical calculation and the experimental verification of the airflow field under the modified slot die were carried out, and the effect of the block structure parameters on the air field was investigated. The research results indicate that compared to the common slot die, the modified slot die with the blocks could increase the velocity on the spinning line and reduce the rate of the temperature decay on the spinning line. When the block width and the block inclination angle lower, and the block height expands, it could increase the peak of the air velocity, the temperature and the turbulence intensity on the center line of the air field under the modified slot die. The average velocity on the spinning line of the modified die under the conditions of block width = 20 mm, block height = 30 mm and block inclination angle = 60° is the highest. [ABSTRACT FROM AUTHOR]

In this paper, to determine the impact of carbon fiber orientation and interweaving on electromagnetic interference (EMI) shielding behaviors, anisotropic and isotropic samples were developed by conductive/dielectric weaving of spatially distributed carbon fiber and glass fiber. Effortless and cost-effective, the electromagnetic shielding efficiency (SE) was up to 42 dB and the SE/thickness) was 41 dB/mm, which had apparent polarization selection characteristics. In addition, the angle (θ) sensitivity for the SE in transverse electric and transverse magnetic polarization modes was given in detail. SE was generally proportional to θ. Moreover, the fingerprint-like radar chart of anisotropic carbon hybrid woven fabrics in the X-band was performed, which makes polarization selection characteristics more intuitive. This paper presented an easy and effective route for assembling hybrid carbon fiber fabrics with high EMI shielding performance, which offers a clear perspective on the simulation and study of carbon fiber electromagnetic properties. [ABSTRACT FROM AUTHOR]

Flax and jute fabrics are adapted to reinforce epoxy matrix composites in order to explore the feasibility of repladng wood in percussion instruments. The fabrics are treated with alkaline solutions to improve interfacial adhesion between fibers and epoxy. The composites are fabricated using the hand-lay and vacuum assisted resin infusion process. Acoustic dynamic moduli, acoustic radiation damping coeffirients, and acoustic impedances of the composites are tested and compared with those of the wood regularly used to make the percussion instruments. It is found that the acoustic properties of the composites are within the range of those of the wood, indicating that it could be feasible to replace the wood with natural cellulose fiber reinforced composites in percussion instrument production. [ABSTRACT FROM AUTHOR]

Based on the research work of traditional electromagnetic shielding fabrics and frequency selective surfaces, the novel high-pass woven fabrics were proposed. Two different unit cell models were built and compared, and a series of design samples were further simulated based on the models. Through contrastive analysis and discussion of the simulated results, the validity of model 1 was verified and the influence rules of various parameters were explored. Compared with model 1, model 2 was more precise containing the textile information, like yarn crimp, fabric porosity and thickness, but model 1 could substitute model 2 to predict the transmission characteristics to some extent. The ratio of conductive and dielectric yarns affected the high-pass characteristics greatly, and different from two-dimensional high-pass woven fabrics, one-dimensional high-pass woven fabrics showed distinct polarization selective characteristics. Yarn electromagnetic parameters and fabric parameters could also exert an effect on the S21 curves in different degrees, which could help designers choose materials and determine the fabric parameters effectively. The modelling and simulation work could provide guidance to the development of actual high-pass woven fabrics. [ABSTRACT FROM AUTHOR]

Planar frequency selective fabrics (FSFs) with Jerusalem-shaped units were proposed in this paper. In accordance with the previous work, the design process was specifically for 10 GHz. Through simulation and optimization procedures, the ideal structure parameters were obtained, and the proposed FSFs with optimized parameters showed good stability to differential and integral algorithms, transmission modes and incidence angles of electromagnetic (EM) waves. To further explore the internal EM transmission mechanism of FSFs, the surface currents at 4, 10 and 14 GHz were analyzed comparatively. Based on the simulated results, 10 samples with the polyester fabric substrate were fabricated through the computer-based carving method and the transmission characteristics were tested using the Shielding Room Method. The fabricated FSFs indeed showed good frequency response characteristics, as expected, and the comparison of measured and simulated results verified the validity of the design procedures. The influence rules of structure parameters (p, a, b, c) were further studied in detail by changing their values properly, and the simplified equivalent circuit model was proposed to explore the corresponding physical mechanism, which could provide physical insight into the performance of the FSFs. [ABSTRACT FROM AUTHOR]

Based on traditional frequency selective surfaces (FSSs), the research ideas of novel frequency selective fabrics (FSFs) are proposed. In this paper, the specific square-loop patch FSF was chosen as an example to illustrate the design procedures, including ANSYS (HFSS) simulation and numerical calculation methods, and then a computer-based experiment was conducted to develop prototypes. Although the simulation, calculation, and experiment results have minor differences, especially the resonance frequency, they show good consistency overall, which demonstrates that traditional design methods could also apply to 2D FSFs. The experiment transmission curve shows obvious band-stop response, peaking at -37.12 dB at the resonance frequency 11.65 GHz, and the narrow bandwidth of -10 dB is predicted from 10.85 GHz to 12.55 GHz. To further verify the validity of design procedures, two complementary cross-shaped FSFs were fabricated through a computer embroidery process, and the experimental transmission curves are complementary as expected, peaking at -26.05 dB and 0 dB at the same resonance frequency 9.65 GHz, and the narrow bandwidths of -10 dB and -0.5 dB are 1.07 GHz and 0.41 GHz, respectively. Although many problems need to be solved in further research, this convenient fabrication method and theoretical basis could make relevant work feasible in later study. [ABSTRACT FROM AUTHOR]

There have been various efforts on frequency selective surface in recent years, and of course, some research progress has been made, especially in numerical calculation and simulation field. However, it seems that less work is done on the processing and forming methods. Soft fabrics are periodic and have advantages over the rigid materials in lightweight, softness, low bending rigidity, which make it possible and meaningful to study their filtering property as the medium in electromagnetic field. In this paper, a kind of electromagnetic functional textile based on frequency selective surface was proposed specifically for 10 GHz, dominant frequency of X-band radar. The full-wave simulation software, HFSS v14, was used for theoretical simulation and optimization, and two complementary cross-shaped unit cells with optimum size were obtained. Then, the frequency selective fabrics were manufactured through silk-screen-printing technology and measured using transmission method. It showed that the measured and simulated results had good consistency, and the fabricated frequency selective fabrics had ideal band-stop or band-pass performance. Finally, according to the analysis of S21 curve and transmission line equivalent circuit modal, the filtering mechanism was explained and the great potential in practical application of frequency selective fabrics was further illustrated. [ABSTRACT FROM AUTHOR]