Filament Count Research Articles

Sample Thickness and Edge Proximity Influence Spatial Behavior of Filaments and Treatment Uniformity of RF Cold Atmospheric Pressure Plasma Jet

The ability of atmospheric pressure plasma jets to treat complex non-planar surfaces is often cited as their advantage over other atmospheric plasmas. However, the effect of complex surfaces on plasma parameters and treatment efficiency has seldom been studied. Herein, we investigate the interaction of the atmospheric pressure plasma slit jet (PSJ) with block polypropylene samples of different thicknesses (5 and 30 mm) moving at two different speeds. Even though the distance between the slit outlet and the sample surface was kept constant, the treatment efficiency of PSJ ignited in the Ar and Ar/O2 gas feeds varied with the sample thickness due to the plasma parameters such as filament count and speed being affected by the different distances of the ground (the closer the ground is, the higher the discharge electric field). On the other hand, the Ar/N2 PSJ diffuse plasma plumes were less affected by the changes in the electric field, and the treatment efficiency was the same for both sample thicknesses. Additionally, we observed a difference in the efficiency and uniformity of the PSJ treatment of the edges and the central areas in some working conditions. The treatment efficiency near the edges depended on the duration of the filament contact, i. e., how long the local electric field trapped the filaments. Conversely, the treatment uniformity near the edges and in the central areas was different if the number of filaments changed rapidly as the discharge moved on and off the sample (the 5 mm samples treated by easily sustained Ar PSJ).

Universal mechanical modeling of fiber bundle under torsion: An experimental and numerical study

AbstractIn this paper, a universal mechanical model for the torsional behavior of fiber bundle was established, grounded in the principles of spatial geometry and continuum mechanics, incorporating differential geometry formulas. The model was validated through self‐designed experimental equipment and finite element simulations using Ansys Workbench, showing strong agreement between predicted torsional fracture behavior and experimental results. The study further examined the contributions of fiber bending, torsion, and tension to the overall torque, revealing that torsion plays the dominant role. Additionally, the effect of filament count on the torsional performance of fiber bundles was analyzed, demonstrating that while the number of fibers significantly influences stress distribution, its impact on overall torque is minimal.Highlights A universal mechanical model for fiber bundle torsional is proposed. High consistency between simulation and experimental results. Examined filament count effect on torsional strength. More filaments reduce stress concentration, improving performance.

Investigating the Effect of Weave Type and Filament Count on Electrical Conductivity of Polyethylene Terephthalate (PET) Fabrics Coated with PEDOT Polymer

The rapid development of smart and wearable textiles has been driven by the need for smaller and lighter electronic circuits. To make textile surfaces conductive, various methods have been developed, with vapor-phase polymerization being a preferred method due to its smoothness, conductivity, and ease of application. This study investigates the effect of fundamental characteristics of textile fabrics, such as weave type and filament count, on electrical conductivity. Fabrics woven with different filament counts and weave types were coated with PEDOT polymer using vapor-phase polymerization. The results showed that the fabric woven with 150F288 yarns and a 3/1 twill weave exhibited lower electrical resistance, attributed to the microfibrous structure of the yarn and the twill's staggered structure. Despite increases in resistance values after performance tests, the electrical resistance values remained within a sufficient conductivity range. This research contributes to the understanding of how fabric characteristics affect the electrical conductivity of coated textiles, paving the way for the development of smart electronic textiles.

Pure chitosan multifilament yarns made using a semi‐industrial pilot scale wet‐spinning process with ionic liquids

AbstractThe ionic liquid 1‐ethyl‐3‐methyl‐imidazolium acetate (EMIMOAc) is used to develop a wet‐spinning process for the manufacturing of chitosan multifilament yarns on a semi‐industrial pilot scale. Commercial chitosans of different qualities, properties, and deacetylation degree ≤85% are used to prepare of spinning dopes with solids content of 6.0–8.5 wt.% using EMIMOAc as a solvent. The viscometric properties are characterized by rheological tests. The manufacturing of the pure chitosan multifilament yarns of different fineness and filament count from the prepared spinning dopes is performed on a pilot wet‐spinning plant. The obtained yarn properties are evaluated by optical (scanning electron microscope, light microscope), structural (infrared spectroscopy, X‐ray diffraction), and textile‐physical characterization. Chitosan multifilament yarns with high performance, tenacities of ~20–26 cN tex−1 and textile processability in weaving, knitting and braiding processes are manufactured in this work.

The use of bundles with higher filament count for cost reduction of high-strength oxide ceramic composites

The use of bundles with higher filament count for cost reduction of high-strength oxide ceramic composites

IN VITRO EVALUATION OF A PILE LOOP KNITTED SCAFFOLD FOR MYOCARDIAL TISSUE ENGINEERING USING C2C12 CELLS

Pile loop knitted scaffold has attracted attention for being used as a three dimensional (3D) biocompatible material particularly for the application of myocardial tissue engineering. In this research, nonintermingled, textured polyethylene terephthalate (PET) multifilament yarn with a filament count of 48 was used for producing a pile loop knit structure to investigate if structure could provide an appropriate microenvironment for the seeded murine C2C12 myoblasts in case of increasing in filament diameter (20.7 micron versus 9.1 micron from the previous study). The resulting structure had a pore network mainly consisting of macropores of 100-200 µm that were well interconnected with micropores (<90 µm). Furthermore, the mean values of the Young’s modulus of the structures at 20% strain were 240.67 kPa in the warp direction, and 85.73 kPa in the weft direction, which can be claimed not to be far from those declared in the literature for the human heart muscle. In addition, the cyclic loading-unloading test revealed no creep in the fabric after 100 cycles. According to the results of the WST-1 assay, the 48 filament-based scaffold was non-cytotoxic for C2C12 cells that were able to proliferate properly on the scaffold, which was visualized by SEM and confocal images. In this respect, pile loop knit structures keep promising results for being used as a cardiac patch.

Measurement of vibration in polyester filament yarns to detect their apparent properties

In this research, an attempt is made to measure the vibrational behavior of polyester filament yarns as a way to identify their physical properties. This is based on the general notion that a change in the physical properties of a string can lead to significant change in its vibrational properties. To conduct the study, a laboratory device equipped with a high-speed digital camera was used to record the vibration of polyester filament yarns at all their points. Video processing was also done to extract the vibration diagrams and to obtain the signal features. The content analysis and the vibration signal processing showed that the filament orientation, yarn count, filament count, appearance of filaments (flat or textured), stimulation distance, and axial tensile force affect some signal characteristics. As the yarn count increased, the frequency, damping, kurtosis of difference signal (FM4) and kurtosis decreased, but the root mean square, four-momentum and energy increased. Moreover, once the stimulation distance increased, the frequency, damping, root mean square, energy, four-momentum and FM4 increased too. An increase in the axial tensile force led to an increase in the frequency and damping but a decrease in the root mean square and energy. Fully drawn yarns (FDY) proved to have the highest frequency, damping, FM4 and kurtosis, and partially oriented yarns (POY) showed the highest energy and four-momentum.

Thermophysiological Comfort Properties of Polyamide Pantyhose

In this paper, the thermophysiological characteristics of low weight knitted polyamide and polyamide/elastane fabrics for pantyhose differing in terms of filament count were studied. Alambeta and Permetest devices were used to measure the thermal conductivity, thermal resistance, thermal absorptivity, evaporative resistance and relative water vapour permeability. The results indicated that fabrics made of finer filaments have lower thermal conductivity, thermal resistance, thermal absorptivity and evaporative resistance values.

Architecture and Transport Properties of Multifilamentary MgB2 Strands for MRI and Low AC Loss Applications.

Standard in-situ type MgB2 strands manufactured by Hyper Tech Inc have 19 - 36 subelements, a monel outer sheath, and a Cu interfilamentary matrix. Typical transport Jc s of the strands are 2×105 A/cm2 with n-values of 20 - 30 at 4.2 K and 5 T. This work introduces two new MgB2 conductor designs. First, a new class of MgB2 strand is designed for magnetic resonance imaging applications. This type has a higher Cu content designed to enhance protection of a magnet wound with it, and a larger diameter to increase the critical current. Second, a new class of low AC loss MgB2 strand with high filament count and a high resistance matrix is discussed. Transport properties at 4.2 K and fields up to 10 T are reported. Optical techniques are used to study the macro- and micro-structures of these MgB2 strands.

3D geometric modelling of discontinuous fibre composites using a force-directed algorithm

A geometrical modelling scheme is presented to produce representative architectures for discontinuous fibre composites, enabling downstream modelling of mechanical properties. The model generates realistic random fibre architectures containing high filament count bundles (>3k) and high (∼50%) fibre volume fractions. Fibre bundles are modelled as thin shells using a multidimensional modelling strategy, in which fibre bundles are distributed and compacted to simulate pressure being applied from a matched mould tool. Finite element simulations are performed to benchmark the in-plane mechanical properties obtained from the numerical model against experimental data, with a detailed study presented to evaluate the tensile properties at various fibre volume fractions and specimen thicknesses. Tensile modulus predictions are in close agreement (less than 5% error) with experimental data at volume fractions below 45%. Ultimate tensile strength predictions are within 4.2% of the experimental data at volume fractions between 40 and 55%. This is a significant improvement over existing 2D modelling approaches, as the current model offers increased levels of fidelity, capturing dominant failure mechanisms and the influence of out-of-plane fibres.

Design, fabrication, and in vitro testing of novel three-dimensionally printed tympanic membrane grafts

Design, fabrication, and in vitro testing of novel three-dimensionally printed tympanic membrane grafts

Electromagnetic shielding characterization of conductive woven fabrics produced with silver-containing yarns

This paper presents a study of the electromagnetic shielding characterization of woven fabrics, produced with two different types of conductive yarns, namely silver-containing (Ag/PA/Co) core yarns and silver-containing (Ag/PA-Co) blended yarns. The effect of various yarn and fabric properties, such as yarn count, core filament count, blend ratio, weft density, electrical resistivity, yarn type and wave frequency, on the electromagnetic shielding effectiveness was investigated. The results have shown that the shielding effectiveness can be tailored by changing the yarn and fabric parameters and also there are significant differences between the electromagnetic shielding characteristics and performances of the fabrics produced with different yarn groups. Such fabrics are future promising for both daily and professional uses, since they combine high shielding effectiveness performance and the comfort properties of conventional fabrics.

Synthesis, spinning, and properties of very high molecular weight poly(acrylonitrile-co-methyl acrylate) for high performance precursors for carbon fiber

Synthesis, spinning, and properties of very high molecular weight poly(acrylonitrile-co-methyl acrylate) for high performance precursors for carbon fiber

Continuous splitting of carbon fibre rovings

Carbon fibres are fabricated in bundles. A single roving contains a minimum of 1000 filaments. Certain applications demand thinner bundles or even single fibres. Single fibres can be used as tool electrodes in electrochemical machining processes. Thinner rovings are needed in sensor applications to raise the electrical resistance of the carbon fibre bundle used as strain sensor. Rovings with a lower filament count cannot be delivered by carbon fibre producers. A splitting technology is therefore needed. A continuous bundle splitting technique was developed. It uses mechanical means, liquid flow and variations in winding force and speed to separate the filaments. The impact of winding parameters and of the liquid flow on the splitting result was quantified in experiments with the developed splitting system. An automatic and continuous splitting of carbon fibre rovings was realised. Smaller bundles of carbon fibre filaments can be provided. There is a solution to satisfy the demand on finer carbon fibre rovings.

Influence of laser striations on the properties of coated conductors

Due to their high current carrying capability, coated conductors are regarded as the most promising high-temperature superconductor tapes for power applications. However, their high aspect ratio causes too high magnetization losses. To reduce the ac loss, one way is to striate the wide tapes into filaments. We used a picosecond laser for the structuring of (RE)BCO coated conductors. The laser allows to burn 18 μm to 21 μm wide grooves (Ag-cap) with a depth between 0.5 μm to more than 100 μm into the coated conductors, with negligible heat effects at the edges of the structures. Different numbers of filament were structured in Cu-and Ag-cap coated conductors. Patterns with up to 120 parallel filaments in 12 mm wide conductor were made. The critical current and the total ac-magnetization loss were measured as a function of the filament count. With an increasing number of filaments Ic degradation occurs. This current reduction has two contributions, the removed HTS material and current inhomogeneities within the superconductor for instance defects along the tape causing secondary phases. For 120 filaments Ag-cap tapes the hysteresis loss reduction is about two orders of magnitude, as expected. The observation of some remaining filament coupling was investigated.

Tracking Actomyosin at Fluorescence Check Points

Emerging concepts for on-chip biotechnologies aim to replace microfluidic flow by active, molecular-motor driven transport of cytoskeletal filaments, including applications in bio-simulation, biocomputation, diagnostics, and drug screening. Many of these applications require reliable detection, with minimal data acquisition, of filaments at many, local checkpoints in a device consisting of a potentially complex network of channels that guide filament motion. Here we develop such a detection system using actomyosin motility. Detection points consist of pairs of gold lines running perpendicular to nanochannels that guide motion of fluorescent actin filaments. Fluorescence interference contrast (FLIC) is used to locally enhance the signal at the gold lines. A cross-correlation method is used to suppress errors, allowing reliable detection of single or multiple filaments. Optimal device design parameters are discussed. The results open for automatic read-out of filament count and velocity in high-throughput motility assays, helping establish the viability of active, motor-driven on-chip applications.

Three-dimensional numerical modelling of discontinuous fibre composite architectures

A three-dimensional geometrical model is presented for generating discontinuous random fibre architectures consisting of high filament count bundles. The fibre network model randomly distributes fibre bundles in a three-dimensional volume using a non-contact algorithm, together with Catmull–Rom spline interpolation, to provide a physically representative material. Only the spines of the fibre bundles are modelled, using truss elements to permit high fibre volume fractions of up to 60%, with no restriction on the fibre bundle aspect ratio. ABAQUS/Standard is used to predict the tensile performance for coupons with varying levels of out-of-plane fibre curvature. The effect of fibre curvature was found to be insignificant for tensile modulus, but a 34% reduction in ultimate tensile strength (UTS) was observed when adjusting the maximum permissible out-of-plane angle of fibres from 1 to 35°. A novel method for characterising the degree of out-of-plane fibre curvature within experimental test coupons is also discussed.

The Effect of Filament Diameter on ${\rm J}_{\rm e}$ in High Filament Count Bi2212/Ag Round Wire

In this study, we investigated the effect of filament size on J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> for high filament count Bi2212 round wire conductors partial melt processed with T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> between 882 and 890degC in pure oxygen. The filament size that produced maximum J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> was between 12 and 15 mum depending on conductor design and T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> . When the filament size was below 12 mum the filaments were unstable during partial melt processing leading to a break-up in the structure of the filament array and low J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> . This effect is attributed the formation of interconnects between filaments which leads to coarsening driven by a reduction in interfacial surface energy.

Random discontinuous carbon fiber preforms: Experimental permeability characterization and local modeling

AbstractInjection experiments indicate that for random discontinuous carbon fiber preforms, increasingly uneven flow fronts develop with increasing fiber bundle length and filament count. While at high propensity for fiber bundle splitting, the preform permeability increases continuously with increasing fiber length, no trend can be identified at low propensity. No clear influence of the virgin bundle filament count on the preform permeability was observed. Types of sizing used on the fibers and bundle cross‐sectional shapes may vary and affect the intrinsic filamentization behavior, thus dominating the preform permeability. In a model for local preform permeability, interbundle voids, distributed randomly across the preform thickness, are approximated via a regular void structure. Simulated filling patterns are qualitatively similar to those observed experimentally, showing more pronounced features than those derived from a model based on local through‐thickness homogenization of the filament distribution. A model based on an alternating arrangement of fiber bundles and voids allows prediction of global preform permeability values from series of injection simulations, showing quantitatively better agreement with corresponding experimental results than the homogenization model. For global permeability, agreement between simulated and experimental mean values improves with increasing fiber volume fraction, whereas calculated coefficients of variation show no strong dependence on the fiber volume fraction. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers

Random discontinuous carbon fibre preforms: Permeability modelling and resin injection simulation

Random discontinuous carbon fibre preforms: Permeability modelling and resin injection simulation