Compact Spin Research Articles

Compact Spinning with Different Fibre Types: An Experimental Investigation on Yarn Properties in the Condensing Zone with 3D-Printed Guiding Device

Abstract The lattice apron-based compact spinning system is a form of pneumatic compact spinning that employs airflow to condense fibres into a bundle, enhancing the yarn’s attributes. To explore the airflow dynamics in pneumatic compact spinning, researchers primarily employ traditional theoretical approaches, experimental measurement techniques, and computational fluid dynamics (CFD) methods. In our previous research, we utilized CFD to observe the airflow patterns in pneumatic compact spinning. In this study, we implemented experimental measurement techniques to assess the impact of a 3D-printed guiding device (B-type) on yarn properties. We tested different fibre types in the condensing zone of the compact spinning system with a lattice apron. We used three types of roving to spin the yarn: pure cotton, cotton/polyester (80/20), and polyester/viscose (65/35). The findings revealed that yarns spun using the guiding device exhibited superior strength, hairiness, and evenness compared to those spun without the device.

Investigating the impact of fiber and yarn structure on yarn tensile properties: A computational approach with artificial neural networks

The properties of yarns strongly depend on the fibers and spinning techniques used to manufacture them. It is imperative to investigate the influence of diverse fibers and yarn structures on the tensile properties of the yarns. Simultaneously, it is equally important to forecast these properties to mitigate costs, reduce waste, prevent faults, and achieve the desired performance in the final products. This study used three different fibers, namely conventional polyester, coolmax, and thermolite, and four different spinning techniques, namely conventional ring, compact, siro, and siro-compact spinning, to develop ring-spun yarns. The effect of fiber and spinning technique was investigated on lea strength (usually taken as count of yarn × lea strength (CLSP)), single yarn strength, and breaking elongation of the developed yarns. An artificial neural network model (ANN) was designed to predict the properties of the yarns using varying fiber types and spinning techniques. The yarns made of conventional polyester fibers resulted in the highest strength of the yarns, whereas coolmax fibers imparted maximum breaking elongation to the yarn compared with other fibers. Conventional ring spun yarns showed minimum strength, whereas siro yarns showed the highest strength among all the yarn samples. The ANN model predicted the CLSP, single yarn strength as well, and breaking elongation of the yarn with the highest accuracy as indicated by the R2-value, which suggests the model can be used reliably and accurately for the prediction of tensile properties of the yarns for different fibers and yarn structures.

VISUALIZING SPUN YARN DEFORMATION: INSIGHTS FROM OPTICAL INSTRUMENTATION

This article presents a comprehensive analysis of key quality indicators for spun yarns, focusing on yarns with a linear density of T=20 (Ne=30) tex produced on both simple and compact ring spinning machines. Through the utilization of optical instrumentation, various parameters including relative breaking strength (Rkm), strength, elongation at break (E %), and hairiness (H %) were meticulously examined to evaluate yarn quality. The study delves into the assessment of yarn unevenness (CV %) as a crucial quality metric, aiming to provide insights into the deformation characteristics of spun yarns. By employing advanced optical techniques, such as high-resolution imaging and precise measurements, the deformation behaviour of yarns under different spinning conditions is elucidated. The findings shed light on the influence of spinning machine type on yarn quality parameters, revealing nuanced differences in strength, elongation, and hairiness between simple and compact spinning processes. Additionally, the analysis highlights the correlation between yarn deformation and overall yarn quality, emphasizing the significance of understanding deformation mechanisms in optimizing textile manufacturing processes. Through a rigorous examination of these quality indicators, this research contributes valuable insights into the intricate dynamics of spun yarn deformation and its implications for textile production. The utilization of optical instrumentation offers a novel approach to visualize and quantify yarn deformation, providing a deeper understanding of the factors influencing yarn quality and performance in industrial settings.

Nonlinear Dirac Equation on Compact Spin Manifold with Chirality Boundary Condition

Nonlinear Dirac Equation on Compact Spin Manifold with Chirality Boundary Condition

Transforming melange fabric waste into mélange yarn employing compact, Siro, and compact-Siro spinning: A cleaner and sustainable strategy

The concept of sustainable and eco-friendly production of textiles has gained significant traction in recent years. Utilizing sustainable raw materials, processes, and recycling methods are fundamental strategies in the development of cleaner and more eco-conscious textile manufacturing. The current work reports a sustainable approach to manufacturing melange yarn from recycled fibers shredded from pre-consumer cotton/viscose mélange fabric waste. The recycled fibers obtained by the shredding method are short and lumpy, necessitating the blending with virgin fibers which serve as carriers throughout the spinning process. In the traditional ring spinning system, the poor inter-fiber cohesion, especially shorter recycled fibers, inhibits achieving the optimum yarn quality. With a view to their better control during spinning, advanced spinning systems such as Siro, compact and compact-Siro spinning were adopted. Experimental results revealed that all these spinning systems led to superior yarn qualities. Among them, yarn produced with compact-Siro spinning demonstrated the most significant improvements in yarn structure (reduced hairiness, unevenness & imperfections) and properties (increased strength & elongation). Through adept engineering and precise process control, 30-Ne (19.68 Tex) melange yarns containing up to 60% recycled mélange fiber were successfully produced. These melange yarns proved to be suitable for manufacturing knit fabrics with aesthetics similar to commercial mélange fabrics. The innovation of producing melange yarn, incorporating 60% recycled fibers, introduces a revolutionary concept aimed at supporting the Sustainable Development Goal (SDG) 12. This initiative aims to reduce the reliance on production of viscose, and cultivating and processing cotton, thereby making significant contributions to environmental conservation in various dimensions. Moreover, embracing this approach offers the potential for cost savings in the production of melange clothing.

Numerical simulation and experimental investigation of lattice-apron compact spinning with an air guide

The four-roller compact spinning system is widely used today and is considered an improvement over traditional ring spinning because of its excellent yarn properties. Reducing energy consumption in compact spinning has always been a key issue for the textile industry. This paper proposed a method for installing an air guide on compact spinning to reduce energy consumption. Four types of air guides were designed with different side shapes (Type-N, Type-L, Type-R, and Type-LR), and the airflow characteristics in the converging zone were analyzed using numerical simulation. In addition, high-speed photography technology and image-processing technology were used to study the dynamic state of the fiber bundle in the flow field of the converging zone. The effectiveness of the preferred solution of the air guide was also verified by spinning experiments. The results revealed that the best air guide was Type-LR, achieving a 3.7% reduction in yarn hairiness even after a decrease in negative pressure by 800 Pa and a 58.4% reduction in power of the fan motor, surpassing the yarn quality observed without any air guide.

Compact spinning: a comprehensive review of the revolution in yarn manufacturing

Compact spinning has emerged as a contemporary spinning technology that has garnered significant attention due to its capacity to produce yarns with excellent properties. The strategy is a variation of conventional ring spinning that seeks to get rid of the spinning triangle while improving the uniformity, strength, and hairiness of the yarn. In compact spinning, fiber condensation is achieved by negative pressure airflow, which compresses the fibers and reduces their thickness. This results in a higher packing density of the fibers, leading to stronger and more uniform yarns. In this article, we provide a comprehensive overview of compact spinning technology, covering its principle, fiber condensation method, and the types of machines used. The quality of the yarn is greatly influenced by various systems and parameters such as lattice apron, air suction slot geometry, airflow fields, and twist mechanism employed in compact spinning. We present a compendium of the various developments established in studies on compact spinning, which could serve as a platform for developing new techniques in compact spinning for the production of high-quality yarns with low economic burdens. This review discusses compact spinning, two main systems, machines, influential parameters/peripherals, disadvantages, and the future prospects of compact spinning. Additionally, we provide a summary of previous research on compact spinning, highlighting its benefits and advantages over traditional ring spinning. Furthermore, we discuss the impact of guiding devices and lattice apron type on yarn quality. We also explore the potential of three-dimensional (3D) printing technology in enhancing the performance and design of compact spinning machines.

Multiple solutions to the nonlinear Dirac systems on compact spin manifolds with boundary

Multiple solutions to the nonlinear Dirac systems on compact spin manifolds with boundary

A systematic improvement to UGA-SSMRCCSD equations and its implication for potential energy curves.

The Unitary Group Adaptation (UGA) offers a very compact and efficient spin adaptation strategy for any spin-free Hamiltonian in a many body framework. Our use of UGA in the context of state-specific (SS) Jeziorski-Monkhorst Ansatz based multireference coupled cluster (MRCC) theory obviates the non-commutativity between the spin-free cluster operators via a normal ordered exponential parametrization in the wave operator. A previous formulation of UGA-SSMRCC by us [R. Maitra, D. Sinha, and D. Mukherjee, J. Chem. Phys. 137, 024105 (2012)], using the same ansatz, employed certain sufficiency conditions to reach the final working equations, which cannot be improved systematically. In this article, we will present a more rigorous formulation that follows from an exact factorization of the unlinked terms of the Bloch equation, resulting in equations on which a hierarchy of approximations can be systematically performed on the emergent additional terms. This derivation was shown in our recent article [D. Chakravarti, S. Sen, and D. Mukherjee, Mol. Phys. 119, e1979676 (2021)] in the context of a single open shell CC formalism and was applied to spectroscopic energy differences where the contribution of the new terms was found to be of the order of ∼0.001eV for ionization potential, electron affinity, and excitation energy. In the current work, we will present a comparison between the earlier and current formulations via both a theoretical analysis and a numerical demonstration of the dramatic effect of the additional terms brought in by the factorization on potential energy curves. The contribution of such terms was found to gain importance with an increase in the number of singly occupied active orbitals in the model space functions.

Trajectorial Dissipation of {Phi }-Entropies for Interacting Particle Systems

A classical approach for the analysis of the long-time behaviour of Markov processes is to consider suitable Lyapunov functionals like the variance or more generally Phi -entropies. Via purely analytic arguments it can be shown that these functionals are indeed non-increasing in time under quite general assumptions on the process. We refine these classical results via a more probabilistic approach and show that dissipation is already present on the level of individual trajectories for spatially extended systems of infinitely many interacting particles with arbitrary underlying geometry and compact local spin spaces. This extends previous results from the setting of finite-state Markov chains or diffusions in mathbb {R}^n to an infinite-dimensional setting with weak assumptions on the dynamics.

Low-regularity Seiberg–Witten moduli spaces on manifolds with boundary

For a compact spin^{c} manifold X with boundary b_1(partial X)=0, we consider moduli spaces of solutions to the Seiberg–Witten equations in a generalized double Coulomb slice in W^{1,2} Sobolev regularity. We prove they are Hilbert manifolds, prove denseness and “semi-infinite-dimensionality” properties of the restriction to partial X, and establish a gluing theorem. To achieve these, we prove a general regularity theorem and a strong unique continuation principle for Dirac operators, and smoothness of a restriction map to configurations of higher regularity on the interior, all of which are of independent interest.

Active particles with delayed attractions form quaking crystallites (a)

Perception-reaction delays have experimentally been found to cause a spontaneous circling of microswimmers around a fixed target particle. Here we investigate a many-body version of such an experiment with Brownian-dynamics simulations of active particles in a plane. For short delays, they form a hexagonal crystallite around the target. The bifurcation to a chiral dynamical phase, seen for longer delays, maps onto that for a single active particle. Different angular velocities at different distances from the target induce shear stresses that grow with increasing delay. By exciting shear bands, they shake and intermittently break the rotating crystallite. For long delays, it detaches from the target to circle around it near the preferred single-particle orbit as a compact spinning satellite, trembling from what could be called tidal quakes.

Valorization of fabric wastes through production of recycled cotton yarns by compact ring and open-end rotor spinning

This study aims to determine the appropriate methods and parameters for the eco-friendly and sustainable production of finer yarns from recycled cotton fibers with acceptable quality and high recycled fiber ratios to transform pre-consumer textile wastes into better-quality products with value-added in the ready-made clothing industry. Cotton fibers were mechanically recycled from dyed fabric wastes. Mélange 100% cotton yarns were produced with different recycled/virgin fiber blend ratios (80/20, 72/28, 64/36, and 56/44) at different yarn counts (30 and 20 tex) and by different spinning methods (compact and open-end spinning) without any chemicals treatment. The yarn properties were tested and compared to determine the best production parameters. As a result of the study, it was seen that the yarn properties improved when the proportion of virgin cotton fiber in the yarn increased in parallel with previous studies. Besides, the yarn hairiness and unevenness of open-end yarns were better than compact yarns. On the other hand, using the compact spinning method led to higher yarn tenacity. The results indicated that the compact spinning method is advantageous in achieving the target of increasing the ratio of recycled fiber use with good tenacity for the production of %100 cotton yarns.

Modification of the Lattice Apron-Type Compact Spinning System with a New Air-Suction Slot for Improving the Yarn Properties

Modification of the Lattice Apron-Type Compact Spinning System with a New Air-Suction Slot for Improving the Yarn Properties

SPICE compact model of controlling electrons of spin qubits using FinFET

Semiconductor qubits have garnered attention in the field of device physics. Owing to the limited coherence of electrons and holes, smaller and more compact qubits are desirable. This requirement is aligned with the miniaturization of conventional transistors. In this study, we consider a compact spin qubit based on the FinFET (Fin Field-Effect Transistor) by using the SPICE (Simulation Program with Integrated Circuit Emphasis) simulator. The qubits are represented by the quantum dots (QDs) between the Fin structure. In order to setup the qubit, we have to control the number of electrons through the FinFET. Here, we consider the circuit model of our system by treating the transport properties of the QD and the FinFET as single-electron phenomena. We provide the SPICE simulation results and show the single-electron current as the functions of the FinFET parameters such as the channel length and width including the operation temperature.

CMOS-compatible ising machines built using bistable latches coupled through ferroelectric transistor arrays

Realizing compact and scalable Ising machines that are compatible with CMOS-process technology is crucial to the effectiveness and practicality of using such hardware platforms for accelerating computationally intractable problems. Besides the need for realizing compact Ising spins, the implementation of the coupling network, which describes the spin interaction, is also a potential bottleneck in the scalability of such platforms. Therefore, in this work, we propose an Ising machine platform that exploits the novel behavior of compact bi-stable CMOS-latches (cross-coupled inverters) as classical Ising spins interacting through highly scalable and CMOS-process compatible ferroelectric-HfO2-based Ferroelectric FETs (FeFETs) which act as coupling elements. We experimentally demonstrate the prototype building blocks of this system, and evaluate the scaling behavior of the system using simulations. Our work not only provides a pathway to realizing CMOS-compatible designs but also to overcoming their scaling challenges.

A short proof of the localization formula for the loop space Chern character of spin manifolds

In this note, we give a short proof of the localization formula for the loop space Chern character of a compact Riemannian spin manifold M , using the rescaled spinor bundle on the tangent groupoid associated to M .

Secondary higher invariants and cyclic cohomology for groups of polynomial growth

We prove that if \Gamma is a group of polynomial growth, then each delocalized cyclic cocycle on the group algebra has a representative of polynomial growth. For each delocalized cocycle, we thus define a higher analogue of Lott’s delocalized eta invariant and prove its convergence for invertible differential operators. We also use a determinant map construction of Xie and Yu to prove that if \Gamma is of polynomial growth, then there is a well-defined pairing between delocalized cyclic cocycles and K -theory classes of C^* -algebraic secondary higher invariants. When this K -theory class is that of a higher rho invariant of an invertible differential operator, we show this pairing is precisely the aforementioned higher analogue of Lott’s delocalized eta invariant. As an application of this equivalence, we provide a delocalized higher Atiyah–Patodi–Singer index theorem, given that M is a compact spin manifold with boundary, equipped with a positive scalar metric g and having fundamental group \Gamma=\pi_1(M) which is finitely generated and of polynomial growth.

Exploratory Study on the Properties of Compact Three-Roving Yarn: Comparison The Properties of Compact Spun, Compact Siro-Spun and Compact Three-Roving Yarns

This study presents the novel compact three-roving technology which developed on the working principle of siro-spun and compact spinning technologies. In the study, auxiliary parts of siro-spun and pneumatic compact spinning are newly designed for the production of compact three-roving yarns. The properties of new compact three-roving yarns were compared with compact spun and compact siro-spun yarns that produced at the same yarn count and at the same twist level from natural, synthetic and regenerated fibers. Besides, three-types of yarns were also used in the weft direction for the production of the woven fabric. Comparing yarn and fabric properties showed that, compact three-roving yarns have similar results to commercially used yarns in general. In addition, it should also be noted that three-roving yarn can be also used for specific purposes owing to its composite structure.

Eigenvalues of the Dirac operator on compact spin manifolds under Ricci flow

In this paper, we first derive the evolution formula for the square of the first eigenvalue λ2 of the Dirac operator under the metric flow ∂∂tg=h on compact spin manifolds. We then prove that λ2 is nondecreasing under the Ricci flow on compact spin surfaces with non-negative Gauss curvature.