Thread Density Research Articles

Considerations on Embroidered Textile Antennas for Wearable Applications

Planar inverted-F antennas (PIFAs) made of woven conductive textiles and of patterns embroidered with conductive threads are investigated. The influence of conductive thread density on antenna properties is considered in both cases. The effect of lockstitch on antenna resonant frequency is quantified. A metallic button is proposed as the transition between textile antennas and classical circuits. A full-textile prototype of a PIFA is designed and shown to operate properly in the ISM 2.4 band.

An analytical model for ballistic impact on textile based body armour

Polymer fibres with high tenacity and modulus such as Kevlar® are widely used in personal protection applications. Normally these fibres are manufactured into different fabric structures before being assembled layer by layer to form personal protection panels. This paper reports on an analytical model of ballistic impact of multi-layer woven fabrics developed based on the momentum theory and analytical models of single-yarn ballistic impact proposed by previous researchers. This model incorporates the effect of various intrinsic parameters such as yarn linear density and fabric thread density and the effect of various extrinsic parameters such as the projectile dimension and mass. The model also takes into account the phenomenon of strain gradient among the panel layers and its effects on the tensile strain at the edge of the projectile and the angle between the impact line and the yarn axis. In addition, possible shear failure is also considered by using shear strength together with maximum tensile strain as the failure criteria. It has been found that the results from the analytical modelling agree closely with the experimental results. Further, the analytical modelling also reveals that the model is useful in describing the strain distribution history in the primary yarns in each layer of fabric in the panel. It has been concluded here and in other published work that during the ballistic impact of multi-layer woven fabrics shear failure occurs before tensile failure for the front layers which prevents the high strength polymer fibres reaching their full energy absorption potential.

Weave analysis of paintings on canvas from radiographs

A spectral algorithm is described for measuring from radiographs the weaving densities of the horizontal and vertical threads that comprise a painting's canvas. A framework for relating spectra to canvas weave type is presented. The so-called thread density and angle maps obtained from the algorithm reveal the canvas's distinctive density variations and provide insights into how the canvas was prepared. Applying a two-stage correlation procedure to the density variations allowed determination of which paintings' support could have been cut from the same piece of canvas. The first stage uses a nonparametric test of the similarity of the probability distributions of two painting's thread counts. The second stage is a new correlation procedure more stringent than the usual cross-correlation function. Examples drawn from the paintings by Vincent van Gogh illustrate the algorithms.

The effect of host web complexity on prey-stealing success in a kleptoparasitic spider mediated by locomotor ability

We examined how the web structure of host spiders affects the locomotor ability of the kleptoparasitic spider Argyrodes kumadai. We compared two populations of A. kumadai differing with respect to whether the host used was Agelena silvatica (Agelenidae) or Cyrtophora ikomosanensis (Araneidae). The barrier web of Agelena had a higher thread density than that of Cyrtophora , which presumably constrains locomotion of A. kumadai in Agelena webs. A reciprocal transplant experiment into different webs revealed that, in complex webs, the A. kumadai population using Agelena as a host walked faster than the A. kumadai population using Cyrtophora ; however, no such difference was found in simple webs. This suggested that A. kumadai using Agelena are better adapted to the webs of their native host with regard to their locomotor ability than are A. kumadai using Cyrtophora . The prey capture success of A. kumadai , as estimated by the foraging response of the host to prey and the walking speed of A. kumadai , revealed that the population of A. kumadai using Agelena captured larger prey much more frequently than the population using Cyrtophora . Thus, the greater locomotor ability of A. kumadai using Agelena appears to be adaptive for enhancing prey acquisition in Agelena webs where prey-stealing opportunities are severely limited. We conclude that both physical web architecture and the foraging behaviour of the host are important selective agents on locomotor ability in Argyrodes .

On the Utility of Spectral-Maximum-Based Automated Thread Counting from X-Radiographs of Paintings on Canvas

This paper establishes that the two-dimensional Fourier transform, spectral-maximum-based extraction of thread density appears suited to automatic thread counting from scanned X-radiographs of paintings for a range of European painters from the seventeenth century to the early twentieth century. With regularly woven canvas, striping occurring in color-coded maps of local thread count can be used to identify rollmate candidates originally separated by as much as a few meters, maybe more. These results suggest that recently developed spectral-maximum-based thread counting algorithms are sufficiently sophisticated to support major efforts in archival thread counting as key forensic data in a variety of art historical investigations. Still, the canvas and priming used by some artists require a more refined approach to automated thread counting than a simple spectral-maximum-based scheme.

Predicting bending rigidity of woven fabrics using artificial neural networks

This paper reports an investigation on the predictability of bending property of woven fabrics from their constructional parameters using artificial neural network (ANN) approach. Number of cotton grey fabrics made of plain and satin weave designs were desized, scoured, and relaxed. The fabrics were then conditioned and tested for bending properties. Thread density in fabric, yarn linear density, twist in yarn, and weave design were accounted as input parameters for the model whereas bending rigidity in warp and weft directions of fabric formed the outputs. Gradient descent with momentum and an adaptive learning rate back-propagation was employed as learning algorithm to train the network. A sensitivity analysis was carried out to study the robustness of the model.

SHAPE OF THINGS: UNDERSTANDING A LOOM WEIGHT

If there is one thing to be learnt from watching people work in old traditional crafts it is this: The tools and the working procedures are never clumsy, never impractical (Hoffmann 1988) SummaryLoom weights are common finds in archaeological excavations in Europe and the Near East. They represent the only remains of warp‐weighted looms. The function of the warp‐weighted loom is well known from ethnographic studies. The function of loom weights, however, has not been investigated and cannot be deduced directly from ethnographical data, since loom weights in antiquity were very different from those used in the twentieth century AD. This paper reviews the functional elements of a loom weight. The weight and thickness of loom weights are established as the defining functional parameters for the operation of the warp‐weighted loom. A series of systematic tests demonstrated that the weight of a loom weight defines what yarn to use and the thread density. The thickness of a loom weight, and thus the width of the row of loom weights hanging closely together, defines the width of a fabric and – together with the weight of the loom weight – the thread count and density of the fabric. This new knowledge provides the methodological framework for archaeologists to calculate textile production possibilities from any given loom weight, as long as the weight and thickness are preserved. Furthermore, it allows scholars to assess textile production on sites where no textiles are preserved.

THE INFLUENCE OF THE WEAVE AND THE METHOD OF STITCHING ON SELECTED MECHANICAL PROPERTIES OF WOVEN DOUBLE FABRICS

Abstract This paper reports the influence of the weave and the method of stitching on the mechanical properties of double woven fabrics. Double fabrics have a more complex construction, which is altered not only by type of weave, yarn fineness, and thread density in comparison with single fabrics, but also by the method of stitching. The main goal of our research was to find out if the type of weave and method of stitching have a statistically important effect on selected mechanical properties of woven double fabrics, such as breaking strength, breaking elongation, tearing strength, wrinkle recovery and fabric stiffness, in order to extend the knowledge of double fabric construction. The testing samples were made from 100% cotton fabrics.

High Frequency Properties of Electro-Textiles for Wearable Antenna Applications

A systematic study of the high frequency electrical properties of electro-textiles is presented in this paper. First, conductive thread characterization is completed with a waveguide cavity method. The effect of conductive thread density and comparison of several different types of conductive threads are included. Second, comparisons of knitted patterns and weave patterns are made in terms of effective electrical conductivity through a microstrip resonator method. The effect of various weave patterns on conductive and dielectric loss is detailed. Finally, the relevance of the high frequency characterization of the electro-textile materials is shown through electro-textile patch antenna fabrication and measurements. The efficiency of the fully fabric patch antenna is as high as 78% due to the use of low loss electrotextiles characterized in this paper.

Influence of helix angle and density on primary stability of immediately loaded dental implants: three-dimensional finite element analysis

To analyze effects of different thread helix angles and densities on the primary stability of immediately loaded implants using the three-dimensional finite element model analysis. Five models of three-dimensional finite element (0.8 mm, 1.6 mm, 2.4 mm, double-threaded, and triple-threaded) were created using the commercial codes of Pro/E software, Hypermesh software, and ABAQUS software. In conditions of horizontal and vertical loading, the micro-motion of the finite element models with different thread helix angles and densities were computed with ABAQUS software. Concerning different thread helix angles, the micro-motion of single-threaded implant was the minimum and that of the triple-threaded was the maximum with vertical and horizontal loading. The micro-motion of doubled-threaded implant was the minimum compared with thread pitch 1.6 mm and the micro-motion of triple-threaded implant was the minimum compared with thread pitch 2.4 mm with vertical and horizontal loading. The thread helix angle and density of implants can greatly affect the vertical interfacial micro-motion. With increasing thread pitchs, the resistance of implant to vertical load is weakened; with increasing thread helix angle, the resistance of implant to vertical load is weakened; with increasing thread density, the resistance of implant to the vertical load is weakened.

CORRECTION OF COLOUR VALUES OF WOVEN FABRICS USING CHANGES TO CONSTRUCTIONAL PARAMETERS

Abstract In practice it happens very frequently that yarn of certain fineness, which creates desired colour effect on the woven fabrics surface, is not available. In consequence an available yarn of different fineness has to be used instead, which can be observed on the woven fabrics as a colour deviation compared with the desired effect. The aim of this research is the possibility of colour values corrections of woven fabrics by changes of constructional parameters. Simulations of woven fabrics are used for this purpose. In the case described weft the yarn of higher fineness is substituted by the yarn of lower fineness and equal colour values. Three possible ways of colour values correction by changes of constructional parameters of the woven fabric are presented. In the first case, the colour difference is corrected by increase of the weft threads density, the second way of correction consists in the change of warp yarn fineness, and the third in decreasing of warp threads density. The basic purpose of all the three types of correction is the equally change of warp and weft contents in one colour rapport of the woven structure. In the experimental part of our work, the colour values L*, a* and b*, and colour differences DE*ab are investigated theoretically (using calculations on the basis of theoretical defined fractions, and L*, a*, and b* values of yarns), as well as spectrophotometrically, on the basis of printouts of simulations of woven fabrics prepared with the use of Arahne CAD system. Two ways of determination of colour values of simulations and three types of corrections are evaluated in the conclusions. It was find out that the correction with the increase of weft thread density is the most successful, and the DE*ab values are minimal.

Developing seamless shaped woven medical products

Currently, the cutting and sewing process is utilized to produce medical products with tailored shape, which leads to a number of adverse consequences due to seams. These drawbacks have prompted us to undertake research to develop new methods by which seamless tubular woven products with inherent shape could be produced. The methods could potentially lead to the design and production of seamless shaped textiles that might be used in a wide variety of medical applications. Three variables were tested, specifically yarn shrinkage, weave designs, and thread density. A variety of samples were woven using different combinations of these variables to create structures with different shrinkage properties. Upon finishing in a solution containing a surfactant and soda ash, the structures experience different degrees of shrinkage resulting in desired shapes. Length and width dimensions of each sample were taken before and after finishing. The change in sample shape due to differential shrinkage in terms of yarn shrinkage, weave, and thread density is reported.

Web tension and gravity as cues in spider orientation

The bowl and doily spider, Frontinella pyramitela (Araneae, Linyphiidae), typically hangs at the lowest point on its concave upward, bowlshaped web (Fig. 1). It returns to the same area after prey capture, courtship, or repulsion of intruders, and naive spiders of either sex come to rest at the same “center of preference”. Because the “center of preference” is not visibly different from other parts of the bowl sheet, it is not obvious what cues the spiders use in establishing its location. Investigation of the roles of gravity, web curvature, thread density and web tension reveals the “center of preference” to be an area no different from others with respect to curvature and thread density but different with respect to tension. Tension in the web is locally high at the “center”, drops as one moves toward the periphery of the bowl, and rises again at the periphery (Fig. 6). The natural relationship between gravity and the orientation of the bowl is not a necessary condition in defining the location of the “center of preference” but gravity is involved in orienting the search for its location (Figs. 3, 4). Altering the pattern of web tension by cutting the tensor threads destroys the accord among spiders as to the location of the “center of preference” and confirms the role of web tension in the orientation of this spider.

Building a better insect trap; An experimental investigation of prey capture in a variety of spider webs.

Web-building spiders (Araneae; Theridiidae, Linyphiidae, Araneidae) are catagorized as searchers because they devote a large amount of energy to the construction of the web which constitutes the search phase in the foraging sequence. In this study search energy is equated with the density of threads in a web and the effectiveness of a variety of webs in three broad catagories (tangle webs, sheet webs & orb webs) is tested in the light of current foraging theory. Within each web type there is a distinct thread density at which the number of approaching Drosophila (Diptera; Drosophilidae) that are captured is maximized (Figs. 1, 2, 3). That maximum results from a combination of factors that are a function of the density of threads in the web. The visibility of the web to an approaching Drosophila increases which acts to decrease the number of flies that enter the web (Tables 2, 3, 4). The ability of the web to detain a Drosophila that contacts it (capture efficiency) increases to an asymptote as a function of thread density (Fig. 4). These data support an assumption of many optimal foraging models that with increasing investment in search the predator receives a diminishing return.More Drosophila intercept orb webs than intercept sheet or tangle webs. In addition orb webs detain a greater proportion of the flies that contact them (Fig. 4). Sheet webs are intermediate between orb and tangle webs in their relative abilities to contact and detain Drosophila.

On the Measurement of Thread Density of Fabrics with Lattice (II)

On the Measurement of Thread Density of Fabrics with Lattice (II)

On the Measurement of Thread Density of Fabrics with Lattice-1

On the Measurement of Thread Density of Fabrics with Lattice-1