Flax/Polylactic Acid(PLA)Core/Sheath Structural Composite Yarn Fabricated by Spindle Braiding Technique

The increasing demand for sustainable and environmentally friendly materials has driven research towards the development of green composites.In this work,the flax/polylactic acid(PLA)braided yarns were fabricated by braiding PLA filaments with 4 to 24 spindles on flax yarns.After curing at different temperatures(180℃and 190℃),the core/sheath structural flax/PLA composite yarns were manufactured.According to the results of the tensile test,the flax/PLA composite yarn with 4-spindle PLA yarns as a sheath layer and at a curing temperature of 180℃reached the maximum elastic modulus of about(5.79±0.65)GPa and the maximum tensile strength of about(162.17±18.18)MPa.This flax/PLA composite yarn with good mechanical properties would be suitable for green composites in the automobile manufacturing industry and building materials.

Tension Active Disturbance Rejection Control of Automatic Yarn Splicing Robots for Ring Spinning

Automatic splicing of interrupted yarns in ring spinning has always been a problem in the industry.Factors such as low yarn strengths and environmental influence on yarn tensions make it difficult to control the yarn tension during the robotic splicing process.The purpose of this research is to design active disturbance rejection control(ADRC)for a third-order nonlinear tension system subject to external disturbances.Firstly,a third-order extended state observer(ESO)is designed to achieve the suppression and the compensation of the internal modeling error and the external disturbances of the system.Secondly,the adaptive gain error feedback control and the filtering process are designed to reduce the influence of sensor noise on the disturbance observation.Finally,the tension control during the splicing process is simulated and experimented,and the experiments show that the method has good robustness in the tension tracking task under a dynamic environment,which verifies the effectiveness of the method.

应用程序属性感知的Yarn资源调度模型研究

Hadoop应用程序存在计算密集属性和调度时间属性,但是Hadoop大数据平台集成的第二代资源管理器Yarn内置的三种资源调度器无法将相同属性的应用程序均衡分配到计算节点上,导致部分节点负载过高,出现严重的计算任务长尾效应。文中提出了一种应用程序属性感知的Yarn负载均衡调度模型——APB Scheduler。APB Scheduler自动感知应用程序属性,将相同属性应用程序的Container按照动态资源计划均衡分配到集群计算节点上,并使用NSGA-Ⅲ算法完成最优分配方案计算。实验结果表明,APB Scheduler解决了相同属性应用程序的Container分配倾斜问题,大幅提升了集群的性能和稳定性。

基于YARN集群的计算加速部件扩展支持

以GPU和Intel MIC为代表的计算加速部件已在科学计算、图形图像处理等领域得到了广泛的应用,其在基于云平台的高性能计算及大数据处理等方向也具有广泛的应用前景.YARN是新一代Hadoop分布式计算框架,其对计算资源的分配调度主要针对CPU,缺少对计算加速部件的支持.在YARN中添加计算加速部件需要解决多个难点,分别是计算加速部件资源如何调度以及异构节点间如何共享问题、多个任务同时调用计算加速部件而引起的资源争用问题和集群中对计算加速部件的状态监控与管理问题.为了解决这些问题,提出了动态节点捆绑策略、流水线式的计算加速部件任务调度等,实现了YARN对计算加速部件的支持,并通过实验验证了其有效性.

基于YARN规范的智能电网大数据异常检测

文章描述了Hadoop早期版本在处理智能电网大数据上的不足,同时分析了YARN规范对Map-Reduce进行改进后对电网大数据处理的优点。文章详细讨论了YARNDPP平台中智能电网大数据处理的编码与实现及YARN-DPP的优势,并以IEEE 118节点的电网作为智能电网大数据异常检测的案例程序,对YARN-DPP平台的硬件环境与软件运行环境进行配置。实验结果表明,针对海量的智能电网状态安全大数据异常检测的程序,YARN-DPP平台具有较好的吞吐量与加速比,可以满足现代智能电网大数据异常检测的需求,在计算速度上比单机串行计算及Map-Reduce计算要快。

YARN平台上的并行主题标引算法

文档主题标引是当前个性化智能检索的重要前提,但面对大规模海量数据资源时,主题标引也成为性能瓶颈。当前在Map Reduce框架上设计实现的主题标引算法,通常存在启动任务耗时长,中间数据过多地进行磁盘IO等缺陷。为了解决此类问题,采用YARN(yet another resource negotiator)作为底层分布式资源管理平台,选择更加合适的计算框架来改善计算性能。针对文档主题标引算法计算步骤多、阶段性强的特点,选择有向无环图(directed acyclic graph,DAG)计算模型进行算法实现,避免不必要的作业拆分,从而减少中间结果的磁盘IO。另外,考虑到Map Reduce的排序策略耗时较多,而有些计算无需对结果排序,故可以改用基于Hash的数据归约策略来提高计算性能,但这又会带来随机读的问题。利用固态硬盘高速随机读的特性,设计相应的优化计算策略来解决随机读的问题。通过实验对比发现,以YARN为底层管理平台,在此基础上选择合适的计算框架并加以优化,可以有效改善分布式计算的性能。

Yarn架构下基于GA的Web日志挖掘技术

提出了一种面向TB级别日志文件挖掘需求的日志挖掘技术。采用MapReduce编程模型设计并实现了一种基于子种群联姻策略的GA,并部署到Yarn架构上,使Yarn架构与GA有效结合。在算法Partition阶段,采用Round-Robin策略代替原有的哈希方法,使各个子种群基因更加趋向均匀分布,增加了子种群收敛效率和结果准确性,同时均衡各个节点运行负载,提高了系统性能。经测试,应用该技术的挖掘结果平均准确度达到93%以上,效率提升接近33%。

Full‑Fiber Auxetic‑Interlaced Yarn Sensor for Sign‑Language Translation Glove Assisted by Artificial Neural Network

Yarn sensors have shown promising application prospects in wearable electronics owing to their shape adaptability, good flexibility, and weavability. However, it is still a critical challenge to develop simultaneously structure stable, fast response, body conformal, mechanical robust yarn sensor using full microfibers in an industrial-scalable manner. Herein, a full-fiber auxetic-interlaced yarn sensor(AIYS) with negative Poisson’s ratio is designed and fabricated using a continuous, mass-producible, structure-programmable, and low-cost spinning technology. Based on the unique microfiber interlaced architecture, AIYS simultaneously achieves a Poisson’s ratio of-1.5, a robust mechanical property(0.6 c N/dtex), and a fast train-resistance responsiveness(0.025 s), which enhances conformality with the human body and quickly transduce human joint bending and/or stretching into electrical signals. Moreover, AIYS shows good flexibility, washability, weavability, and high repeatability. Furtherly, with the AIYS array, an ultrafast full-letter sign-language translation glove is developed using artificial neural network. The sign-language translation glove achieves an accuracy of 99.8% for all letters of the English alphabet within a short time of 0.25 s. Furthermore, owing to excellent full letter-recognition ability, real-time translation of daily dialogues and complex sentences is also demonstrated. The smart glove exhibits a remarkable potential in eliminating the communication barriers between signers and non-signers.

Analysis on the Characterization of the Twist Insertion Level and Its Effect of the Compact and Ring Spun Yarns

In this paper, the difference of the twist insertion levels of the compact and ring spun yarns of the same count is analyzed based on the relationship of the yarn twist factor to the twist angle and the bulk density. It is proposed that the relationship of the twist angle, twist level, and the yarn diameter should be synthetically considered when evaluating the twist insertion level of the compact yarn. The twist angle of the compact yarn is smaller than that of the ring yarn with the same twist insertion level. This results from the ordered fiber arrangement and compact structure of the compact yarn. Experiment was conducted to verify the conclusions. It is also discovered that the selection of the twist factor of the compact yarn, which can be usually lower than that of the ring yarn by 10%-15%, can be determined based on the yarn tensile strength.

Radial Yarn Movement in Yarn Duct of Interlacer

In order to find the relations between the production performance of interlacer and its cross-sectional shapes of yarn duct,radial yarn movement in various yarn ducts of interlacer and its effect on performance of interlaced yarn were studied in this paper.Seven interlacers,which were different in the cross-sectional shape of yarn duct,were made.Yarn motion in yarn duct of interlace was observed with optical fibers and photo-sensors.Performance of the interlaced yarn was evaluated by the number and the strength of tangles.Experimental results disclose the relations between the yarn motions and the properties of the interlaced yarn.The interlacer with round yarn duct is capable of producing an interlaced yarn with bigger number of tangles,since it can make yarn transverse frequently the axis of air jet issuing from air jet nozzle.The interlacer with cornered shape of yarn duct makes yarn subjected to the action of compressed air for a longer time,which results in larger strength of tangles.

Scalable Core–Sheath Yarn for Boosting Solar Interfacial Desalination Through Engineering Controllable Water Supply

Tailoring water supply to achieve confined heating has proven to be an effective strategy for boosting solar interfacial evaporation rates.However,because of salt clogging during desalination,a critical point of constriction occurs when controlling the water rate for confined heating.In this study,we demonstrate a facile and scalable weaving technique for fabricating core-sheath photothermal yarns that facilitate controlled water supply for stable and efficient interracial solar desalination.The core-sheath yarn comprises modal fibers as the core and carbon fibers as the sheaths.Because of the core-sheath design,remarkable liquid pumping can be enabled in the carbon fiber bundle of the dispersed superhydrophilic modal fibers.Our woven fabrics absorb a high proportion(92%)of the electromagnetic radiation in the solar spectrum because of the weaving structure and the carbon fiber sheath.Under one-sun(1 kW·m^(-2))illumination,our woven fabric device can achieve the highest evaporation rate(of 2.12kg·m^(-2)·h^(-1) with energy conversion efficiency:93.7%)by regulating the number of core-sheath yarns.Practical application tests demonstrate that our device can maintain high and stable desalination performance in a 5 wt%NaCl solution.

Prediction of Rotor Spun Yarn Strength Using Adaptive Neuro-fuzzy Inference System and Linear Multiple Regression Methods

This paper presents a comparison study of two models for predicting the strength of rotor spun cotton yarns from fiber properties. The adaptive neuro-fuzzy system inference （ANFIS） and Multiple Linear Regression models are used to predict the rotor spun yarn strength. Fiber properties and yam count are used as inputs to train the two models and the count-strength-product （CSP） was the targel. The predictive performances of the two models are estimated and compared. We found that the ANFIS has a better predictive power in comparison with linear multiple regression model. The impact of each fiber property is also illustrated.

Advances in Electrospun Nanofiber Yarns

In order to increase the application area of nanofibers,electrospun nanofiber yarns have drawn attention of many researchers around the globe.Once the production method of nanofiber yarn is mature enough to be universally accepted,many new gates of applications will open to the world.In this review,different electrospinning techniques of electrospun nanofiber yarns are divided into needle electrospinning and needleless electrospinning.Considering yarn twist as an important mechanism,needle electrospinning technique is further categorized into mechanical,electrical and field flow twisting methods.Moreover,parameters influencing the mechanical properties of electrospun nanofiber yarns are investigated.Methods of improving mechanical properties of nanofiber yarns are addressed,including hot-water-bath treatment,addition of carbon nanotubes(CNTs)and introducing regulators.Finally,applications of electrospun nanofiber yarns in different fields of smart textile and bioengineering are summed-up.In summary,challenges encountered in the industrialization of nanofiber yarns and future prospects are anticipated.

The Influence of Elimination of Roving Frame on Ring Spun Cotton Yarn Characteristics

Generally, ring spun yarns are manufactured from roving which is produced by roving frame. In this paper, an experiment has been done producing ring spun cotton yarn directly from finisher drawn sliver eliminating the roving frame. Total 3 types of yarn with the various linear density of 8 Ne, 10 Ne & 12 Ne were produced using a roving frame and without using a roving frame. In the next step, physical and mechanical properties of those yarns including unevenness, imperfections, hairiness & tenacity were investigated. The result showed that ring spun cotton yarns produced from sliver exhibited inferior physical and mechanical properties compared with samples from the conventional ring spinning system.

一种YARN和Spark框架的网格聚类方法

分布式计算为大数据的处理提供一种新的平台,能有效提升算法的执行速度。在DBSCAN算法基础上提出一种数据分网格算法,该算法将每个分区上的数据集划分成以Eps半径为边长的单元格数据块,将查找Eps邻域的范围缩小到数据对象的八个相邻单元格之内,从而提高查找Eps邻域的速度及聚类速度,具有较好的加速比和扩展率。同时还优化分区聚类合并方法。

Abrasion Resistance Comparison between Rotor and Ring Spun Yarn

On the base of literature review and the analysis of yarn properties, yarn structure and some other facts, the abrasion resistance of both rotor spun yarn and ring spun yarns are discussed. The results show that with the same raw material and twist, the rotor spun yarn has lower abrasion resistance than that of ring spun yarn, because of the higher twist employed, the abrasion resistance of rotor spun yarn is higher than that of ring spun yarn.

一种基于YARN的高优先级作业调度实现方案

提交到YARN上的一个大数据作业会被切分为一个或者多个任务,任务是大数据作业申请资源和执行的基本单位[1]。在某些领域中存在需要对作业紧急度作有效区分使得高紧急度作业优先获得资源的需求,但是在现有的YARN资源调度策略中,对于提交到YARN上的高优先级作业缺乏资源优先分配和高质量的资源保障机制。本文在修改YARN原有资源调度方案的基础上,提出了一种基于YARN的高优先级作业调度实现方案。实验表明,提交到YARN上的高优先级作业执行效率提升了7%左右,证明设计方案行之有效。

一种Hadoop Yarn的资源调度方法研究

针对Hadoop Yarn资源调度问题,为提高集群作业执行效率,提出一种基于蚁群算法与粒子群算法的自适应Hadoop资源调度算法SRSAPH.SRSAPH中,通过Hadoop Yarn跳通信机制获取负载、内存、CPU速度等属性信息初始化信息素矩阵;同时,将粒子群算法的自我认知能力与社会认知能力引入到蚁群算法,提高算法的收敛速度;此外,根据蚁群算法全局最优解的波动趋势动态调整信息素挥发系数,提高解的精度.实验表明,采用SRSAPH进行资源调度,集群的作业执行时间缩短至少10%.

Comparison of the Vortex and Ring Spun Cotton Yarns and Their Knitted Fabric Properties

Vortex spinning is an innovative air-jet spinning technology with promising features.A comparison of the vortex and ring spun cotton yarns and their knitted fabric properties was provided to evaluate the latent capability of the vortex spinning technology.The results show that the vortex yarn has better elongation,evenness and much less hairiness than the ring yarn.The vortex fabric is found to have better air permeability,bursting properties,and pilling resistance than the ring fabric,while the drapeability and abrasion resistance of the ring fabric are better than the vortex fabric.

Experimental Simulation and Analysis of the Yarn Motion Track in a Hairiness-Reducing Nozzle

A visible magnified and simulated nozzle was designed and installed on a winding machine according to the similarity principle of Reynolds number, to study the yarn motion track in hairiness-reducing nozzle. High-speed photography was used to observe the yam instantaneous motion state in the nozzle. The results show that the yarn motion track seems to be a cylindrical helix which is close to inner wall in the twisting chamber and kept the same with different technical parameters, such as diameter of the twisting chamber and jet pressure in orifices. According to simulation results and reasonable simplification, the motion track equation and the rotational equation of the yarn could be derived. The velocity of the swirl and hairiness is faster than that of the yarn balloon, so there is enough time for hairiness to be wrapped into the main body of yarn and hence the hairiness is reduced.