Traditional Spinning Research Articles

Time Donating Barrier for efficient task scheduling in competitive multicore systems

Nowadays, co-locating multithreaded applications on a multicore system has increasingly become a common case in cloud data centers, where multiple threads generally compete for computing resources. These competitive environments may suffer problems of system throughput and fairness caused by barrier operations in multithreaded applications. This is because most implementations of the barrier synchronization are based on the spin-then-block mechanism in which spinning–waiting threads probably waste computing resources and relinquish cores to other co-running applications after they are blocked. This paper attempts to find a new and intuitive way to improve the efficiency of barrier in competitive environments, and answer the question: Can we leverage the timeslices of waiting threads to accelerate barrier operations?Targeting this question, we propose a novel barrier synchronization mechanism named Tidon (Time Donating Barrier). The basic idea of Tidon is to donate the timeslices of waiting threads to their preempted, laggard siblings in order to accelerate barrier operations, different from traditional static spinning and blocking. We implement Tidon based on the GNU OpenMP runtime library (libgomp) and Linux kernel with new, lightweight system calls. Our evaluation with various sets of co-running applications demonstrates that the advantages of Tidon include (1) alleviating the performance degradation of barrier-intensive applications (e.g. improving the performance by up to a factor of 17.9 and 2.3 compared to the default barrier implementation of OpenMP in Completely Fair Scheduler and Balance Scheduling, respectively) while not hurting or even improving the performance of non-barrier-intensive applications, and (2) maintaining good fairness among co-running applications (e.g. improving the fairness by up to a factor of 19.8 and 1.7 compared to the default barrier implementation of OpenMP in Completely Fair Scheduler and Balance Scheduling, respectively).

Experimental research on oblique cone die-less shear spinning

In order to break through the limitation of traditional axisymmetric spinning, a discretization method is made to form an oblique cone by die-less shear spinning technique. Due to the characteristics of asymmetric spinning, the roller feed should harmonize with the spindle rotation, and the roller path is derived through a discretization method. The thickness variation of oblique cone in different directions is coincident with the sine relation in axisymmetric shear spinning. The surface quality, especially the surface smoothness (the distribution of arrises) and surface roughness of the spun part, is discussed by analyzing the roller motion and important spinning parameters, and a smaller axial feed rate f and a smaller angle increment Δ α can improve the surface quality.

Research on pneumatic compact spun yarn quality

Compact spinning is one of the most important improvements of traditional ring spinning, which is implemented by adding a fiber condensing device to condense the fiber bundle and decrease the spinning triangle. Pneumatic compact spinning is the most widely used compact spinning method at present. Compact spinning with perforated drum and compact spinning with lattice apron are the two main kinds of pneumatic compact spinning. Therefore, in this paper, comparison analysis of yarn quality between compact spinning with perforated drum and compact spinning with lattice apron is presented. First, 9.7 tex cotton-combed yarn is spun in three different kinds of pneumatic compact spinning systems, including two kinds of compact spinning with perforated drum: Rieter’s COM4 and complete condensing spinning system (CCSS), and one lattice apron compact spinning system: Toyota’s four-line compact spinning. The test results of yarn qualities show that comparing with other two kinds of compact spinning systems, the yarn spun in CCSS has the best evenness, least long hairiness, and slightly lower strength. Then, the properties of spun yarns are analyzed using two methods. First, using Fluent Software, numerical simulations of three-dimensional flow field in condensing zone of three kinds of compact spinning system are presented, respectively. Second, the fiber movements in condensing zones are captured using high speed camera system OLYMPUS i-speed3.

A numerical study of the effects of roller paths on dimensional precision in die-less spinning of sheet metal

Die-less spinning eliminates the dependence upon the mandrel of traditional spinning, but bringing about comparatively poor dimensional accuracy which needs to be improved. In this paper, roller paths in the first pass of die-less spinning, including concave, convex, linear and combined ones are parameterized according to the degree of bending and their effects on dimensional precision (thickness variation and shape deviation) have been studied by using experiments of finite element (FE) analysis. The effects of roller paths on thickness variation, shape deviation, tool forces, and stress and strain variations have been analyzed numerically. The results showed that for concave roller paths, the thickness variation is not very sensitive to the degree of bending, while a low degree of bending of the roller path can result in a low shape deviation. For convex roller paths, a low degree of bending leads to both low thickness reduction and low shape deviation. Further research shows that a combined roller path with convex-concave curve could contribute a low shape deviation, while an inverse combined roller path gives better thickness precision.

Facilely fabricating PCL nanofibrous scaffolds with hierarchical pore structure for tissue engineering

Highly hierarchical pore structure (macro–micro–nano) for biomimetic nanofibrous scaffolds could efficiently enhance cell infiltration and tissue formation. However, it is difficult to prepare these structures by using traditional electrostatic spinning techniques. Here, we report a facile method to fabricate polycaprolactone (PCL) nanofibrous scaffolds with multi-scale pore structure by simple phase separation. By employing water–dioxane as solvents and tris spheres as macropore template, PCL nanofibrous scaffolds with pores 300–800µm, 1–10µm and 100–1000nm in diameter can be facilely produced. All scaffolds possess controlled nanofibrous morphology and porosity (90–98%). This scaffold may provide promising applications in tissue engineering and drug delivery.

Effect of methylimidazole on cellulose/ionic liquid solutions and regenerated material therefrom

Cellulose, especially wood-based cellulose, is increasingly important for making everyday materials such as man-made-regenerated textile fibers, produced via dissolution and subsequent precipitation. In this paper, the effect of cosolvents in ionic liquid-facilitated cellulose dissolution is discussed. Both microcrystalline cellulose and dissolving grade hardwood pulp were studied. Three different cosolvents in combination with ionic liquid were evaluated using turbidity measurements and viscosity. The ionic liquid precursor N-methylimidazole proved to be a promising cosolvent candidate and was thus selected for further studies together with the ionic liquid 1-ethyl-3-methylimidazolium acetate. Results show that dissolution rate can be increased by cosolvent addition, and the viscosity can be significantly reduced. The solutions were stable over time at room temperature and could be converted to regenerated textile fibers with good mechanical properties via airgap spinning and traditional wet spinning. Fibers spun from binary solvents exhibited significantly higher crystallinity than the fibers from neat ionic liquid.

Fabrication of innovative charkha for pashmina spinning and its impact assessment

Pashmina, a finest natural animal fiber is utilized for preparation of world famous Kashmiri pashmina shawls by traditional practices. Hand spinning is one of the important processing step, wherein fibers are converted into a fine yarn on a traditional spinning wheel (yander). The task is usually carried out by women folk. It is a laborious process resulting in a lot of physical stress affecting the efficiency of artisans. An innovative charkha has been fabricated to reduce the physical stress and its effect on the spinning efficiency and remuneration of artisans over traditional one was evaluated. The study revealed that innovative charkha was efficient in terms of time consumed for spinning by 73.50% over traditional one besides decreasing physical drudgery. In terms of income, there was an increase of 146% over traditional one for same period of time without deteriorating the quality of yarn.

Morphological aspects of polymer fiber mats obtained by air flow rotary-jet spinning

Fiber mats were obtained by using a modified rotary-jet spinning system, which allows a forced air flow produced by an air compressor to interfere with the polymer jets. The main focus of current studies rely on the range of morphological and dimensional characteristics of fibers that may be expected when using this new technical setup of a rotary-jet based spinning system. In fact, this work represents a proof of concept study regarding the potential of an air flow modified rotary-jet spinning for obtaining continuous fibers and nonwoven mats. The morphological examinations by scanning electron microscopy were proved the efficiency of this technique on obtaining relative homogeneous fiber mats from different raw compositions of pure and admixed, natural and synthetic polymers with different molecular masses and polydispersity degrees, like gelatin, polyurethane, and poly (vinyl chloride). The feasibility of air flow rotary-jet spinning was also tested for simultaneous independent deposition of mixed fiber mats from solutions of two polymers made in different solvents, and it was found that by carefully selecting the ratio of polymers through spinnerets number, this technique could be successfully used even in difficult solvent conditions otherwise incompatible with traditional spinning techniques. The distribution of fiber diameters was varying between nanometer scales (100–700 nm) in the case of pure polyurethane and micrometer ranges (2–12 µm) for gelatin-polyurethane mixed mats, which are convenient for various applications, from dressings and scaffolding to different filter systems. Besides the already known advantages of rotary-jet versus electrospinning, the air flow allows the control of solvent evaporation, extending the applicative range of this technique.

A study of the spinning force of hollow parts with triangular cross sections

The noncircular spinning is one of the recent breakthroughs of the traditional spinning processes. The spinning force is one of the important parameters for designing the spinning equipment and one of the main factors influencing the forming quality of spun parts. The variation of spinning force during noncircular spinning is considerably different from that of the conventional spinning due to the high-speed reciprocating movement of the roller induced by the variable spun workpiece profile. This paper presents an experimental investigation of spinning force characteristics of a hollow part with triangular cross sections using an octagon ring transducer based on electrical measuring method. A series of experiments using profiling driving spinning method was carried out to study the effects of the main process parameters, such as the roller feed rate, blank thickness–diameter ratio, and mandrel rotational speed, on the spinning force characteristics. The important characteristics of the force components of noncircular spinning were discussed based on the electrical measuring results. Furthermore, the variations of force components were compared with those obtained in the cases of conventional spinning and 3D non-axisymmetrical spinning. The results show that different from the conventional spinning and similar to the 3D non-axisymmetrical spinning, the three components of spinning force along the axial, radial, and tangential direction of roller vary periodically with the mandrel rotational angle. Different from the conventional and the 3D non-axisymmetrical spinning, the maximum spinning force is related to the mandrel rotational speed, even if the feed rate of roller remains constant, and increases with the increase of the mandrel rotational speed.

Production of high bulk polyester filament yarn

This paper reports a method for producing high bulk polyethylene terephthalate (PET) filament yarns composed of shrink and nonshrink filament yarns. Normally, high bulk yarns are mainly made out of shrink and nonshrink staple fibers especially polyacrylonitrile through semi-worsted spinning process. The method described in this paper involves blending two PET filament yarns, one acting as shrink component and the other as nonshrink one, followed by a relaxation process. The amount of shrinkage of the shrink component can be regulated by the drawing ratio employed during the drawing of partially oriented PET yarn. Depending on the shrinkage of shrink component, a variety of high bulk PET continuous filament yarns can be produced. The method described in this paper has the advantage of a much shorter production route and production cost, when compared with the traditional semi-worsted spinning process. Some of the produced yarns showed a high similarity with the fancy boucle yarns.

Investigation on stress and strain distributions of hollow-part with triangular cross-section by spinning

The non-circular cross-section hollow-part spinning is one of the recent breakthroughs of the traditional spinning processes. To reveal the mechanism of the non-circular spinning, the spinning process of the hollow-part with triangular cross-section was investigated. The spun part was divided into the straight-side and filleted-corner along the circumferential direction, and the bottom-corner, side-wall and opening-end along the generatrix direction. The simulation results show that during the non-circular part spinning, wrinkling occurs easily at the flange area of the straight-side; the distributions of equivalent stress and strain are 120° uniformly distributed along the circumferential direction. The differences on distributions of equivalent stress and strain between straight-side and filleted-corner are obvious. The maximum equivalent stress locates at the opening-end, where springback occurs easily. The maximum equivalent strain locates at the bottom-corner of straight-side and the centre of the side-wall of filleted-corner, where over-thinning of wall thickness occurs easily. The strain states of the straight-side and filleted-corner are different, the former is approximately in the state of plane strain and the latter is in the state of volumetric strain. A non-circular spinning device was designed and manufactured, a set of experiments were carried out. The experiment results conform well with the simulation one.

Influence of Technological Parameter for Ramie Yarn Hairiness on Compact Spinning with Suction Groove

The application of compact spinning technology with suction groove for ramie was studied. This technology improved ramie yarn hairiness, breaking strength and so on. The performance of the yarn hairiness was analyzed in detail through contrast test of the compact spinning technology with suction groove and the traditional ring spinning for ramie fiber. At the same time, the comprehensive performances of ramie yarn spinning by the two kinds of spinning technologies were contrasted and analyzed. The results showed that the spinning technology with suction groove can be significantly improved ramie yarn properties: hairiness and breaking strength etc. In the spinning technology with suction groove, the optimal technological parameter for producing least yarn hairiness, A1 B1 C1 D1, is acquired, where the spindle speed A is 6600 r/min, twist B is 608 T/m, the value of negative pressure C is -3.1 kPa, and traveler D is 21 # (yarn Nm 36).

Wet spinning of cellulose from ionic liquid solutions–viscometry and mechanical performance

AbstractA series of regenerated cellulose fibers was produced from dopes prepared by mixing and dissolving cellulose of two different degrees of polymerization in different ratios in the ionic liquid 1‐ethyl‐3‐methyl‐imidazolium acetate. Viscoelastic properties of the spin dopes were characterized by controlled stress rheometry. The cellulose solutions were solidified in pure water by the traditional wet spinning technique. The resulting fibers were characterized by means of wet and dry tensile testing and scanning electron microscopy. The characterization revealed a compact and homogeneous fiber. A nonlinear relationship between degree of polymerization and fiber properties was observed with a moderate difference in mechanical properties in a broad interval of fibers while fibers composed of polymers with the highest degree of polymerization stood out as stronger and stiffer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Study on the Wool-Solospun Spinning Technology

Solospun spinning is a new type of wool-spinning methods, Solospun spinning technology principles and characteristics were introduced in the paper, the domestic-manufacture fluted Roller was used on the existing equipment and the production was carried on,In addition to comparing with the traditional ring spinning production ,the structure and performance of two kinds of threads had been tested ， the yarn comprehensive performance judgement was also given.it was proofed that the solospun-spinning yarns was better than the ring spinning yarns.

Biological effects of melt spinning fabrics composed of 1% bioceramic material

This study evaluated the usefulness of bioceramic materials (ceramic materials that emit high-performance far-infrared (FIR) rays), processed into fabrics using a traditional manufacturing melt spinning method. Numerous measurements were designed to test the biological functions of 1% bioceramic fabrics. These included physical induction of intracellular nitric oxide (NO) in NIH 3T3 cells (mouse fibroblasts), the effects on cell viability in osteoblastic cells (MC3T3-E1) under hydrogen peroxide-mediated oxidative stress, and the effects on lipopolysaccharide (LPS)-induced cyclo-oxygenase-2 (COX-2) and prostaglandin E2 (PGE2) production in a chondrosarcoma (SW1353) cell line. When compared to the control group, the bioceramic fabrics were capable of inducing further intracellular NO production using NIH 3T3 cells, and maintaining increased viability and against cell intoxication of osteoblastic cells by suppressing cell release of lactate dehydrogenase (LDH) under oxidative stress. In addition, it was found to suppress LPS-induced COX-2 production more significantly in a SW1353 cell line. These processes represent the biomolecular changes occurring during promotion of decline in aging, prevention of osteoporosis, and prevention of inflammatory processes within the human body. Therefore, these bioceramic fabrics are likely to fulfill their claims of having health-promoting benefits.

1P1-H09 メカトロガラ紡の小型化とFPGAを用いたコントローラの開発(生産システム・生産機器メカトロニクス)

Conventional spinning machinery had been the purpose of generating a uniform thin yarn. Therefore, the development and improvement of the machine has been conducted for low-cost, high-speed, high volume production. At present, the development of special raw materials such as carbide fiber and metal fiber, yarn production and special demand of high-mix low-volume production have emerged. In addition, the increase of recycling activities in consideration of resource saving and cost reduction, and environmental issues, has also sought reclaimed fiber. Focused on the Garabo spinning that can be spun there special fibers. However, Traditional Garabo spinning machine is relatively large and productivity is low. In this study ,miniaturization and improved productivity of the machine spun glass has been investigated

Investigation on the spinnability of metallocene cyclic olefins copolymer melt

This work investigates the melt spinning process of the metallocene cyclic olefins copolymer (mCOC), which had never been successfully developed before. The shear-viscosity examination reveals that the mCOC has a mild shear thinning tendency due to the presence of cyclic olefins, but is very sensitive to the temperature variation. The optimal melt extrusion temperature for the mCOC is found between 320 and 330°C. The mCOC is known to have high Tg, which would cause early solidification, seriously broken filaments, and winding interruption during the melt spinning process. Accordingly, the traditional spinning process employing an air-quenching system at 18°C for polyolefins, such as polypropylene and polyethylene, is inappropriate for the mCOC. Experimental results reveal that in melt spinning of the mCOC, it is necessary to install a heating board of 1.4 meters length and heated up to 180°C to assisting with the spin draw ratio of the mCOC. The elongation rheology of the mCOC was found to be greatly affected by the presence of cyclic olefins. The optimal spinning speed is 1500 m/min. In such a speed, the spin draw ratio of the mCOC is 90, which is higher than the literature value of 10[11], but still far smaller than 200–400 for typical linear polymers. Experimental results suggest that hot drawing, with a drawing ratio of 1.15 and godet temperature of 200°C, can yield yarn with optimal tenacity of 1.4 g/den. Birefringence observations indicate that mCOC yarn, even via melt spinning and hot drawing, does not exhibit any bulk orientation. The result of X-ray diffraction implies that hot drawing can enhance the formation of nano-crystals with an average size of approximately 6.5 nm. This takes place on the short linear olefin chains among the cyclic segments. The degree of crystallization increases slightly as the godet temperature increases.

Study on Alginate Fiber Core-Spun Yarn by Friction Spinning

Alginate fibres are difficult to spin on the traditional ring spinning machine. Friction core-spun yarn which took alginate fibers as main wrapped fibers and cotton yarn as core yarn were developed on DREF-Ⅲ. The influence of main spinning technical parameters, such as spinning speed, friction roller speed and core yarn percentage, on the yarn performances was studied by means of orthogonal experiment and the optimized technical was put forward. The results showed that the overall performance of the core-spun yarn would be better as spinning speed of 100 m/min, friction roller speed of 4000r/min, core yarn percentage of 50% respectively.

The process of development Korean traditional wooden spinning top-Pangee for young children

The process of development Korean traditional wooden spinning top-Pangee for young children

Numerical Simulation on Efficient Spinning Technology Based on Multi-Point Adjusting Principle

In order to realize high efficiency and flexible manufacturing for rotary surfaces, efficient spinning technology (EST) is researched. It is the combination of multi-point forming and traditional spinning. Principle of EST is described, traditional spinning method is compared with it, and characteristics of it are analyzed. Finite element analysis (FEA) model of disc-shape part is established, EST process is analyzed, equivalent stress and plastic strain distributions are analyzed. EST equipment is developed, and the experiments are made. Results indicate: EST process consists of four stages; equivalent stress in sheet metal’s center region and bendable rollers active region exceeds yield stress, and plastic deformation is generated; experimental result accords with simulation result. Feasibility of EST is validated by simulation and experimental results.