Compact Spin Research Articles

Effect of Geometrical Yarn Parameters: Conventional and Compact Ring Spinning on Certain Functional Properties of TiO2NPs Treated Woven Cotton Fabrics

Abstract Nanotechnology became a core of many research works specially in textiles field as it is being applied to obtain such effective properties that were not exist until its applications in smart textiles. The development of fibers spinning techniques have created a relationship between the geometrical parameters of yarns and performance properties of the resulted fabrics. Fabrics woven using compact cotton yarns found to have better UV protection and water-vapor transmittance than those of combed yarns. The compactness, evenness and low hairiness of such yarns have created an integrated structure that enhanced fabrics UV protection and water-vapor passage through fabrics. TiO2NPs have improved total fabrics performance specially for UV protection, while samples of compact yarns had a better result for both properties.

Determination of the optimum technological criteria under different spinning systems affecting the yarn hairiness

Yarn hairiness is reflected the amount of free fibers protruding from the spun yarn body towards the outer yarn surface. From a spinning point of view, studying this phenomenon is considered essential step because it influences the post spinning operation and the characteristics of the end textile structure. Many spinning factors are affecting the yarn hairiness.The main objective of this search is to examine the effect of yarn count and twist multiplier on yarn hairiness under six different spinning systems. Accordingly, three yarn counts (40's, 50's and 60's Ne) and three twist multipliers (4, 4.4 and 4.8) were applied. The used spun systems were carded, combed, carded compact, combed compact, jetring carded and jetring combed systems. Three-dimensional response surface graphs were used to easy and faster understand the results. Results indicated that the lowest hairy yarn was spun by jetring combed spinning system with significant differences compared to the other spinning systems. Jetring carded and combed compact ring spinning systems occupied the second order regarding the production of the least hairy yarns with significant differences than the others. Overall the used spun systems, it is indicated that the hairy yarns may be dramatically decreased with increasing yarn count to a certain extent and then slightly decreased while the hairiness was gradually decreased with increasing twist multiplier. However, the percentage of decrease % of hairy yarn with increasing yarn count was greater than that observed by increasing twist multiplier under all spun systems. Multiple regression analysis exhibited that yarn count and twist multiplier explained the most variation of hairiness expressed as high values of coefficient of determination (R2 %). Also, it is presented that the relative importance % of yarn count toward yarn hairiness was greater than that observed by twist multiplier overall applied spun systems.

Research on yarn qualities modified by mechanical false-twisting device

In the ring-spinning process, the area between the front roller nip and twisting point is spinning triangle, and its geometry influences the fiber tension distribution in the spinning triangle directly and determines the properties of spun yarns. Therefore, in the paper, one kind of mechanical false-twisting device was introduced on the ring spinning, which can affect the twist propagation and change the spinning triangle geometry actively. First, the modification of the false-twisting device on the DTM129 ring-spinning frame was introduced. Taking the medium cotton yarn spinning as an example, corresponding ring yarn, Sirospun yarn, compact yarn were spun on the modified spinning frame under different designed twist factors, and the applicability of the false-twisting device on different spinning method was discussed. It is shown that comparing with the common yarn, the Hairiness and Strength of the modified yarns are all improved, and the effect of false-twisting device on yarn qualities is more effective for the low-twist yarn. Comparing with the ring spinning, the improvement degree of the modified compact spinning is a little smaller. Then, the long-staple cotton ring yarn, polyester and medium cotton blend ring yarn, polyester ring yarn were spun on the modified spinning frame under different designed twist factors, and the applicability of the false-twisting device on different fibers was discussed. It is shown that the influence of the false-twisting device on the long-staple cotton yarn and polyester yarn is little. That is, the false-twisting device given in the paper would be more applicable on the short fiber spinning under the low designed twist factor.

Silica aerogel/polyester blankets for efficient sound absorption in buildings

In this paper sound absorption characteristics of silica aerogel/polyester (PET) blankets are investigated. PET fibers were made on an industrial scale compact melt spinning line and then processed on a laboratory scale needling line to produce nonwoven fabrics. The silica aerogel blankets were prepared by in situ synthesis of silica aerogel on the nonwoven fabrics via a two-step sol-gel process of tetraethoxysilane which was followed by drying at ambient pressure. In order to achieve aerogel particles with different pore structure and properties, various synthesis conditions were used. The nonwoven samples were characterized in terms of thickness, fiber diameter, porosity and pore size by X-ray micro-computed tomography and scanning electron microscopy. Moreover, nitrogen adsorption analysis was carried out to determine the specific surface area and pore structure of aerogel particles.The effect of pore structure, physical properties and hydrophobicity of aerogel particles on sound absorption coefficient (SAC) of blankets was investigated using two-microphone transfer function method. Also, the effect of sol volume and nonwoven thickness was investigated. The results indicated that at all frequency levels, silica aerogel/PET blankets enjoy higher SAC than their untreated counterparts. It was found that, SAC is strongly affected by the pore structure of aerogel particles. Silica aerogels with lower bulk densities, larger pore size and higher porosities exhibited better sound absorption performance. The results also indicated that hydrophobic aerogel blankets exhibit higher SAC as compared with hydrophilic blankets. The results also showed that the thickness of nonwoven fabric strongly affects the SAC of aerogel blankets.

Infinite loop spaces and positive scalar curvature in the presence of a fundamental group

This is a continuation of our previous work with Botvinnik on the nontriviality of the secondary index invariant on spaces of metrics of positive scalar curvature, in which we take the fundamental group of the manifolds into account. We show that the secondary index invariant associated to the vanishing of the Rosenberg index can be highly nontrivial, for positive scalar curvature Spin manifolds with torsionfree fundamental groups which satisfy the Baum--Connes conjecture. For example, we produce a compact Spin 6-manifold such that its space of positive scalar curvature metrics has each rational homotopy group infinite dimensional. At a more technical level, we introduce the notion of "stable metrics" and prove a basic existence theorem for them, which generalises the Gromov--Lawson surgery technique, and we also give a method for rounding corners of manifold with positive scalar curvature metrics.

Statistical Analysis of Properties of Compact Yarn Produced from Different Process

Compact spinning system is a great modification of ring spinning system. It brings a revolution over ring spinning system in case of hairiness and strength of yarn. In this paper, three yarn of “34’s Ne” count was produced in three different spinning systems termed as conventional Ring, Suessen Elite compact, and RoCoS (Rotorcraft) compact spinning system. During processing, all the processing parameters and the environment were kept the same in the case of the compact spinning system. Yarn properties are then tested with Uster Evenness Tester 6 and Mesdan strength tester. Statistical analysis like t-test paired two samples for means for all the properties of two compact yarns such as unevenness percentage, imperfection index, hairiness, tenacity, elongation, and count strength product were performed using Microsoft Excel 2013. Suessen Elite compact spinning system shows good results than another compact spinning system. It was found from the statistical analysis that there is no significant difference in the maximum properties of two compact spinning systems, especially in hairiness and tenacity, as these two properties are crucial in the compact spinning system.

The effect of mercerization process on physical, chemical and mechanical properties of compact cotton gassed yarns.

There is a deficiency in both aesthetic and functional properties of cotton yarns (carded, combed) and thus the fabrics produced from them (weaving, knitting, domestic fabrics) manufactured from the most spinning methods achieving the aesthetic and functional properties of yarns "compact spinning". In order to contain the yarns on a fair number of dead, immature and short fibers, which are inflexible because these fibers are hollow with a few convolutions in it, which causes their conglomeration and cohesion with each other during the spinning process so-called "Neps" and hairiness. Which is detrimental to the appearance and regularity of both cotton yarns and fabrics especially after the final processing. In terms of functionality, these imperfections (IPI) reduce the tensile strength, elongation, uniformity of yarns, their resistance to wrinkle, friction due to the weakness of flexibility and softness, which leads to shortening the life span of fabrics produced from them. Increases such imperfections (IPI) clearly in both yarns and fabrics, especially with the low quality of current Egyptian cotton grades.

Observing the steady-state visual evoked potentials with a compact quad-channel spin exchange relaxation-free magnetometer**Project supported by the National Key Research and Development Program of China (Grant Nos. 2016YFA0300600 and 2016YFA0301500), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos. XDB07030000 and XDBS32000000), the National Natural Science Foundation of China (Grant Nos. 11474347 and 31730039), and the Fund

We observed the steady-state visually evoked potential (SSVEP) from a healthy subject using a compact quad-channel potassium spin exchange relaxation-free (SERF) optically pumped magnetometer (OPM). To this end, 30 s of data were collected, and SSVEP-related magnetic responses with signal intensity ranging from 150 fT to 300 fT were observed for all four channels. The corresponding signal to noise ratio (SNR) was in the range of 3.5–5.5. We then used different channels to operate the sensor as a gradiometer. In the specific case of detecting SSVEP, we noticed that the short channel separation distance led to a strongly diminished gradiometer signal. Although not optimal for the case of SSVEP detection, this set-up can prove to be highly useful for other magnetoencephalography (MEG) paradigms that require good noise cancellation. Considering its compactness, low cost, and good performance, the K-SERF sensor has great potential for biomagnetic field measurements and brain-computer interfaces (BCI).

Comparison between two differential graded algebras in noncommutative geometry

Starting with a spectral triple, one can associate two canonical differential graded algebras (DGA) defined by Connes (Noncommutative geometry (1994) Academic Press Inc., San Diego) and Frohlich et al. (Comm. Math. Phys. 203(1) (1999) 119–184). For the classical spectral triples associated with compact Riemannian spin manifolds, both these DGAs coincide with the de-Rham DGA. Therefore, both are candidates for the noncommutative space of differential forms. Here we compare these two DGAs in a very precise sense.

The Kernel of the Rarita–Schwinger Operator on Riemannian Spin Manifolds

We study the Rarita-Schwinger operator on compact Riemannian spin manifolds. In particular, we find examples of compact Einstein manifolds with positive scalar curvature where the Rarita-Schwinger operator has a non-trivial kernel. For positive quaternion K\"ahler manifolds and symmetric spaces with spin structure we give a complete classification of manifolds admitting Rarita-Schwinger fields. In the case of Calabi-Yau, hyperk\"ahler, $G_2$ and Spin(7) manifolds we find an identification of the kernel of the Rarita-Schwinger operator with certain spaces of harmonic forms. We also give a classification of compact irreducible spin manifolds admitting parallel Rarita-Schwinger fields.

Comparing Quality Parameters of Yarn Produced by Ring, Rotor, and Compact Spinning System

The end use of a garment depends on the properties of a fabric. A fabric property depends on the properties of the constituent yarn. With the diversification of the market, spinners are forced to produce quality yarn. For this reason, conventional hand spinning has been converted to modern system gradually. Ring spinning, Rotor spinning, and compact spinning are widely used spinning system. Ring spinning is the universal spinning system covering the largest area of yarn production. The yarn produced by Ring, Compact, and rotor spinning systems belongs to different structures and properties. Yarn produced Ne 22's, 100% cotton yarn from the above systems, and their properties were tested by UT5 and Titan Universal strength tester. However, this paper focuses on comparing the yarn properties (U%, CmV%, Imperfection, Hairiness, Strength, and elongation) of ring, compact, and rotor spun yarn. Also, it has been observed that yarn produced by compact spinning system revealed highest strength and elongation, least hairiness, and mass irregularity than the other two spinning systems. In addition, it has been observed that rotor spun yarn displayed less mass irregularity than ring spun yarn.

Effect of different methods of spinning cotton on yarns and fabrics produced

Varied methods of spinning cotton, Effect of different spinning of yarns on both natural and mechanical properties of fabrics produced,, and with a lack of research on the impact of this difference between the use of types and methods Different yarn properties of yarns produced and to determine the contrast ratio on properties of fabrics produced yarns are spun by different spinning methods this study was conducted which show the influence of different methods of yarn used on properties of cotton and fabrics produced, in order to study the production of cotton yarn Characteristics of best reflected their performance on the job performance of fabrics produced using different spinning methods has been used four different spinning methods (Ring "carded and combed", Compact, Open end) to produce yarns number 40 cotton and used three different densities of weft (90, 110, 130) to produce fabrics under consideration, Performed various tests on yarns and fabrics produced to illustrate the relative impact of the difference caused by different search variables change. The results showed a clear difference in some tests of yarns and fabrics produced. Problem:Lack of research on the influence the effect of different spinning yarns on their properties and their reflection on fabrics produced.Objective:Study of cotton yarn production with better reflected their performance on the job performance of fabrics produced using different spinning methods. Importance:Determine the best method for spinning yarns used in the production of study yarn count (40 ne), and their reflection on fabrics produced in different density weft produced from the same yarns. Research methodology:4 sample of yarns that are used as weft in different spinning methods produced fabrics. Using yarns in fabrics produced by three different densities of weft (90, 110, 130) to produce fabrics under consideration. Research Results: Compact spinning yarns produced the highest value of the tensile strength, and RKM, elongation and higher thickness, but open-end spinning method less tensile strength, less RKM, and the lowest elongation. The ring carded spinning yarns produced the highest value of naps, and thin places. The ring combed spinning and compact spinning yarns produced the less value of naps, and thin places . Open-end spinning yarns produced The highest proportion of thick places and Coefficient of variation (CV), while compact spinning less proportion of CV. Open-end spinning yarns produced The highest proportion of weight the square meter and tear resistant for fabric produce, while compact spinning less proportion of weight the square meter. Open-end spinning yarns produced

Strength distribution superiority of compact-Siro spun yarn

This study examined the superiority of the strength of compact-Siro spun yarn. First, the strength properties of four types of yarn—ring, compact, Siro, and compact-Siro spun yarn—were compared based on an experiment with 9.7 tex and 14.6 tex polyester yarns. Yarn unevenness and compactness were analyzed in terms of their influence on yarn strength. It was determined that compact spinning enhanced the strength distribution by improving the overall yarn compactness. Siro spinning significantly increased the minimum yarn strength by reducing unevenness. Furthermore, compact-Siro spun yarn, which incorporates the advantages of both compact and Siro, remarkably improved the yarn strength distribution. These results were verified in the first part of the experiment. Finally, the four types of yarn were applied in the same weaving process. The results indicated that the efficiency of weaving with compact-Siro pure polyester yarn was higher than that of other methods by 3%–6%, thereby confirming the superior productivity of the method.

Effect of pın spacer apparatus on the propertıes of knıtted fabrıcs from cotton-tencel yarns

Yarn quality is an important factor as it directly plays an important role in fabric properties. Among many attempts for improving yarn properties in spinning technologies, pin spacer is one of the developed apparatus which can be mounted separately on the compact spinning unit used for improving the yarn properties especially in terms of yarn evenness and hairiness. Cotton-Tencel blended compact yarns are widely preferred among the textile consumers owing to high comfort feature of Tencel fibers combined with cotton fibers’ unique properties. In this study, cotton (85%) – Tencel (15%) compact yarn samples were produced as yarn groups of combed yarn and carded yarn with utilizing and without utilizing pin-spacer apparatus at a linear density of Ne 40/1. In order to analyze the effect of pin-spacer apparatus on yarn properties, unevenness, imperfections, hairiness (H) and tensile measurements were evaluated. The greige and dyed single jersey plain knitted samples produced from those yarns were also compared in terms of dimensional changes in wale and course direction (%), pilling grades, bursting strength (kPa), air permeability values (mm/s) and the fabric surface color properties. According to test results, using pin-spacer apparatus generally improved carded and combed compact yarns’ some properties as well as some knitted fabric properties made of those yarns.

Numerical and experimental study of the influence of nozzle flow parameters on yarn production by jet-ring spinning

Yarn hairiness is defined as the protruding fibers and loops standing out of the core of the yarns. Effect of yarn hairiness on different post processes, and its influence on the characteristics of the product obtained, has led to attempts at reducing hairiness. In recent years, new technologies such as compact spinning, solo spinning and jet-ring spinning have been developed to reduce the hairiness of ring spun yarn. In this paper, a Computational Fluid Dynamics (CFD) model is presented to study the effects of some air jet nozzle structural parameters as injector angle, nozzle length, and air pressure level on the swirling flow generated inside the nozzle. Followed by design and construction of a mechanism for producing jet ring and modified jet ring yarns. Finally, an experimental study on the effects of some nozzles and air flow parameters on jet ring and modified jet ring yarn properties is presented intending to illustrate the role of inserting the air jet nozzle for improving these systems.

Riemannian submersions and factorization of Dirac operators

We establish the factorization of Dirac operators on Riemannian submersions of compact spin$^c$ manifolds in unbounded $KK$-theory. More precisely, we show that the Dirac operator on the total space of such a submersion is unitarily equivalent to the tensor sum of a family of Dirac operators with the Dirac operator on the base space, up to an explicit bounded curvature term. Thus, the latter is an obstruction to having a factorization in unbounded $KK$-theory. We show that our tensor sum represents the bounded KK-product of the corresponding $KK$-cycles and connect to the early work of Connes and Skandalis.

ESTIMATION OF TENSILE STRENGTH AND UNEVENNESS OF COMPACT-SPUN YARNS BY USING HVI FIBER PROPERTIES

Compact spinning system, which has begun to gain an important place in textile industry, thanks to its desired yarn characteristics, was developed in the early 2000s.  Less hairy yarns can especially be produced with this system, as stated in the literature. Moreover, the system has significant advantages in terms of tensile strength. In this study, yarns were produced with different yarn counts (Ne 40 - Ne 90) and different twist coefficients (αe 3.8, αe 4.2 and αe 4.6) using the compact spinning system. Regression analysis was carried out using the test results of the yarns produced and HVI fiber properties which were measured before the production. It was investigated whether the properties of the yarns can be estimated before production by using specified fiber properties. As a result of the analysis, the derived equations were used to estimate tensile strength and unevenness values of the yarns. 

Subadditivity and additivity of the noncommutative Yang-Mills action functional

We formulate notions of subadditivity and additivity of the Yang-Mills action functional in noncommutative geometry. We identify a suitable hypothesis on spectral triples which proves that the Yang-Mills functional is always subadditive. The additivity property is stronger in the sense that it implies the subadditivity property. Under our hypothesis, we also obtain a necessary and sufficient condition for the additivity of the Yang-Mills functional. An instance of additivity is shown for the case of noncommutative n-tori. We also investigate the behavior of critical points of the Yang-Mills functional under additivity. In the end, we discuss examples involving compact spin manifolds, matrix algebras, noncommutative n-torus, and the quantum Heisenberg manifolds to validate our hypothesis.

Theoretical and experimental study of color-alternation fancy yarns produced by a double-channel compact spinning machine

The aim of this work is to explore a new method for producing color-alternation fancy yarn on a modified compact spinning machine. Color-alternation fancy yarn is a new kind of fancy yarn with varying color effects along the yarn axis. The modified compact spinning machine produces double-channel compact spinning, which has two coaxial back rollers in a drafting unit. In this spinning process, two different colored rovings are alternately fed into each back roller to produce alternant color effects along the yarn axis. The mean length of the connecting piece between of two different solid color pieces of this yarn is the key research subject. Mathematical equations have been derived to describe the relationship between the mean length of the connecting pieces, the mean length of the wedged broken end of roving, the mean overfeeding length of the roving and the total draft ratio. The effect of the total draft ratio and overfeeding length on yarn properties, such as tenacity, elongation and yarn evenness, was studied. The results indicate that a relatively small total draft ratio is beneficial to shorten the mean length of the connecting pieces, enhance the tensile property and improve yarn evenness.

Numerical simulation of flow field in the pneumatic compact spinning systems using Finite Element Method

PurposePneumatic compact spinning is the most widely used compact spinning method at present, in which the negative pressure airflow is used to condense the fiber in order to decrease the spinning triangle and improve the yarn qualities. Therefore, the research on flow field in the condensing zone is always the emphasis for pneumatic compact spinning. The paper aims to discuss these issues.Design/methodology/approachBy using finite element method (FEM), the flow field in two kinds of pneumatic compact spinning was studied. Taking three kinds of cotton yarns as examples, with the help of high-speed camera system OLYMPUS i-SPEED3, the motion trajectory of fiber strand in the condensing zone was obtained. Three-dimensional physical models of the condensing zone of the two compact spinning systems were obtained according to the measured parameters of practical spinning systems.FindingsIt is shown that on the both left edge of B1 line and right edge of B2 line, the airflow inflows to the center line of suction slot, and the condensed effects are produced, correspondingly. In the condensing zone, there are three condensing processes acting on the fiber strand, including the rapid condensing effects in the front condensing zone, the adequately condensing effects in the middle condensing zone, and stable output effects in the back condensing zone.Originality/valueBy using FEM, numerical simulations of three-dimensional flow field in condensing zone for two kinds of pneumatic compact spinning with lattice apron were presented, and corresponding spun yarn qualities were analyzed.