Comparative Study of Polypropylene Non-Woven Surgical Mask and Locally Manufactured Woven and Knitted Fabrics Facial Masks

The outbreak of coronavirus has led to an increase in the demand for facemasks globally. Unavailability of appropriate polypropylene non-woven fabrics face masks as a result of inadequate supply to satisfy the growing population has brought about the manufacturing of locally fabrics masks to augment or substitute standard medical class facemasks. The study aims at analyzing airflow of these locally manufactured fabrics to determine possible means of transmitting the virus as well as establish comfort of the user of these masks. Standard polypropylene non-woven, woven and knitted fabrics were considered for the study. Air permeability test was conducted on these fabrics using Frazier Air permeability tester. Depending on the property significant variation in the textile fabrics, polypropylene non-woven is widely accepted for facial masks. Nevertheless, this study illustrates that woven and knitted fabrics have more open structures, which allow a high rate of air penetration and so may require two or three layers to prevent antimicrobial or antiviral potential.

Automatic Image Inspection of Fabric Defects Based on Optimal Gabor Filter

An effective method for automatic image inspection of fabric defects is presented. The proposed method relies on a tuned 2D-Gabor filter and quantum-behaved particle swarm optimization( QPSO) algorithm. The proposed method consists of two main steps:( 1) training and( 2) image inspection. In the image training process,the parameters of the 2D-Gabor filters can be tuned by QPSO algorithm to match with the texture features of a defect-free template. In the inspection process, each sample image under inspection is convoluted with the selected optimized Gabor filter.Then a simple thresholding scheme is applied to generating a binary segmented result. The performance of the proposed scheme is evaluated by using a standard fabric defects database from Cotton Incorporated. Good experimental results demonstrate the efficiency of proposed method. To further evaluate the performance of the proposed method,a real time test is performed based on an on-line defect detection system. The real time test results further demonstrate the effectiveness, stability and robustness of the proposed method,which is suitable for industrial production.

A Cell-Based Smoothed Finite Element Method for Modal Analysis of Non-Woven Fabrics

The combination of a 4-node quadrilateral mixed interpolation of tensorial components element(MITC4)and the cell-based smoothed finite element method(CSFEM)was formulated and implemented in this work for the analysis of free vibration and unidirectional buckling of shell structures.This formulation was applied to numerous numerical examples of non-woven fabrics.As CSFEM schemes do not require coordinate transformation,spurious modes and numerical instabilities are prevented using bilinear quadrilateral element subdivided into two,three and four smoothing cells.An improvement of the original CSFEM formulation was made regarding the calculation of outward unit normal vectors,which allowed to remove the integral operator in the strain smoothing operation.This procedure conducted both to the simplification of the developed formulation and the reduction of computational cost.A wide range of values for the thickness-to-length ratio and edge boundary conditions were analysed.The developed numerical model proved to overcome the shear locking phenomenon with success,revealing both reduced implementation effort and computational cost in comparison to the conventional FEM approach.The cell-based strain smoothing technique used in this work yields accurate results and generally attains higher convergence rate in energy at low computational cost.

Preparation of UV-curable Nano-silver Antimicrobial Agent and Its Application in Non-woven Fabric

Nano-silver and waterborne polyurethane(WPU)composite emulsion was synthesized.The average diameter of silver nanoparticles(SNPs)was about 20 nm,and the average diameter of WPU was 101.32 nm.The anti-bacteria finishing of a polypropylene non-woven fabric(NWF)was carried out by ultraviolet finishing technology and the double dipping twin-roll method.The standard AATCC100 was used to test the antimicrobial activity of the samples.The results showed that the antimicrobial rates of Klebsiella pneumoniae(K.pneumoniae)and Staphylococcus aureus(S.aureus)were above 90%,which indicated that the NWF finishing had good antimicrobial activity.In addition,the thermal stability,mechanical properties,whiteness and contact angle of antimicrobial finishing nonwovens were characterized.The results showed that the performance of antimicrobial nonwovens was stable at 300℃.The breaking strength was better than that of untreated nonwovens,and the contact angle reached 119.1°.

Beijing Dayuan Non-woven Fabric Co.Ltd

Situated in the Shilong Industrial District of Mentougou, Beijing, the Beijing Dayuan Non-woven Fabric Co. Ltd is a Sino-foreign joint venture producing non-woven fabrics, set up in 1991.

基于红外图像的织物水分动态传递性能测定方法

为提升织物水分动态传递性能测定的准确性,解决图像技术测定过程中织物润湿区域提取困难的问题,选用了红外热像仪对织物水分动态传递过程进行观测,构建了一款基于红外图像的织物水分动态传递性能测定系统。系统可将录制的织物水分动态传递红外成像视频按设定的参数依次进行图像提取、分割、双边滤波处理和二值化处理,并将处理得到织物水分润湿图像按照像素比例自动换算成织物实际润湿面积值输出,以自动测定织物水分动态传递性能。采用该系统测量了6种织物试样的水分动态传递性能,验证了该测定系统的准确性,并分析了6种织物的水分传递性能差异。结果表明:该测定系统能计算出织物水分动态传递过程中各个时刻的润湿面积,且结果准确性高。测试数据分析发现,织物水分传递初期的速度与织物面密度和总紧度呈明显负相关,与理论分析一致。

基于U-Net卷积神经网络的织物压力传感阵列串扰解决方法

为解决压阻式柔性压力传感阵列中存在的异常传感单元与串扰现象导致采集到的压力数据不准确的问题,构建了具有32×32个传感单元的压阻式柔性织物压力传感阵列系统,对传感单元检测值出现异常的原因进行了分析,采用中值滤波算法对系统获取的压力分布云图中的异常值进行处理;针对串扰现象,构建了U-Net卷积神经网络模型,采用机器学习方法对织物压力传感阵列系统生成的压力云图进行修正,设计了模型输入、输出数据集的采集方法。结果表明,经中值滤波算法处理后的压力云图的峰值信噪比处于30~40 dB之间,反映出中值滤波算法对异常值处理的效果较为理想;U-Net卷积神经网络模型训练过程中的均方根误差最终达到7.1,表明模型获得了较好的训练效果,通过与无串扰效应的柔性压力传感阵列采集的压力云图进行对比,表明U-Net模型能够有效消除串扰现象对织物压力传感阵列压力云图显示结果的影响。

成形网对液压过滤材料性能稳定性的影响

液压过滤材料在过滤过程中会出现过滤比严重下降的问题,极大影响了滤材过滤性能的稳定性。首先利用Geodict软件模拟了滤材孔径分布不均匀对过滤性能的影响,结果表明,在平均孔径一定的情况下,滤材的最大孔径越大,滤材过滤性能的稳定性越差;然后采用实验探究了成形网目数对滤材孔径分布以及液体过滤性能的影响,结果表明,当成形网的目数大于等于400目时,不同直径、不同定量的滤材在成形过程中的流失率和孔径分布逐渐趋于稳定,在滤材的物理参数和过滤精度接近时,500目成形网制备的滤材过滤性能的稳定性要高于80目成形网制备的滤材。

基于机载LiDAR点云数据的建筑物三维模型重建方法研究

根据建筑物点云的分布特征,提出一种机载LiDAR点云建筑物三维模型重建方法。首先,利用布料模拟滤波算法剔除地面点,实现包含建筑物点云在内的非地面点提取,并利用最大类间方差法提取建筑物点云;其次,使用Alpha Shape算法提取建筑物点云中边缘点,并规则化处理建筑物轮廓线,通过屋顶分割算法提取建筑物屋顶信息;最后,使用SharpGL工具进行建筑物三维模型重建。以某地级市某地区机载LiDAR点云数据为例进行实验,结果表明该方法进行建筑物三维模型重建具有较高的精度与效率,适用于城镇复杂区域建筑物三维模型重建。

Scheme for Designing the 1-D Convolution Window of Gabor Filter

A scheme for designing one-dimensional (1-D) convolution window of the circularly symmetric Gabor filter which is directly obtained from frequency domain is proposed. This scheme avoids the problem of choosing the sampling frequency in the spatial domain, or the sampling frequency must be determined when the window data is obtained by means of sampling the Gabor function, the impulse response of the Gabor filter. In this scheme, the discrete Fourier transform of the Gabor function is obtained by discretizing its Fourier transform. The window data can be derived by minimizing the sums of the squares of the complex magnitudes of difference between its discrete Fourier transform and the Gabor function's discrete Fourier transform. Not only the full description of this scheme but also its application to fabric defect detection are given in this paper. Experimental results show that the 1-D convolution windows can be used to significantly reduce computational cost and greatly ensure the quality of the Gabor filters. So this scheme can be used in some real-time processing systems.

A STUDY OF THE SPECIMEN SIZE OF STRIP TENSILE TEST FOR NEEDLE-PUNCHED NON-WOVEN GEOTEXTILES

In this paper,the failure features of strip tensile specimen were observed and analysed for need-le-punched non-woven geotextiles.A mechanical model which expresses the relation between thetensile modulus,the strip specimen size,contraction factor and the tensile strength of non-wovenfabric was derived.The theoretical prediction showed that the main factor influencing tensilestrength of non-woven geotextile specimens with different size is the contraction factor of specimenor the specimen aspect ratio(width/length).The larger the aspect ratio,the higher the tensilestrength test value of geotextiles,but the experiments showed that the specimen tensile strength isnot increased with increasing the width of specimen.The reason was discussed and it seemed thatthe deviation could be served as an indication of the degree of imperfectness of the non-wovenstructure.

Relationships between the Processing Parameters of Melt Blown Nonwoven Fabric and Its Structure and Filtration Property

Based on the processing experiment and sodium flame test this paper deals with the relationship between processing parameters, structure, and filtration property of melt blown fabric. Through the image analysis of Questar micro-images in combination with the SEM observation and the measurement of some macrostructure indices, the relationship between the processing parameters and the structure especially the microstructure is emphasized Finally the effect of somestructure factors on filtration properties is discussed theoretically.

Fabric Structure for Moisture Retention Property and Its Application in Civil Engineering

The article reveals the development and analysis of fabric structure for its moisture absorbency property and its application in Civil engineering for curing of concrete. The presence of moisture in concrete and time of curing are the major influencing factors for concrete strength. Normal practice of curing is to wrap the concrete with jute woven fabric and spraying of water. The absorbency characteristics of different GSM (Gram per square meter) of woven and Non-woven fabric were studied. The Non-woven fabric absorbency is superior to woven fabric of same GSM by its three dimensional structure and high pore volume. The strength of concrete cured with Non- woven fabric is 2.1 N/mm2 higher than woven fabric of same 350 GSM. The difference in compressive strength of Non-woven fabric of 350 GSM and 750 GSM is 0.06 N/mm2 which is marginal.

Color-Changing Fabric System with Temperature Control

Color-changing fabric system with temperature control is designed through textile design and electronic technology.The system inserts a conductive fabric inside a fabric coated with thermochromic powder.A temperature control system is constructed to adjust the current to raise the temperature of conductive fabric to the active point of thermochromic powder and keep the temperature in stable.Therefore,the fabric could sense the temperature and change colors.In order to achieve wearability,mobile power supply is selected and flexible sensor is adopted.Kalman filter is engaged in the proportion integration differentiation(PID)control algorithm to reduce the interference of measurement noise.The experiment result shows that the proposed color-changing fabric system could reach the target temperature quickly and meet the design demands for color-changing.

Cost analysis and comparison of plain cotton and disposable non-woven treatment towels

Objective: To choose a reasonably priced and low-cost treatment towel suitable for clinical application of hospital so as to reduce the cost of the hospital and make a reasonable use of resources through the cost analysis and comparison of the plain cotton and disposable non-woven treatment towels. Methods: The cost of the single pack plain cotton towel and disposable non-woven towel were analyzed and at the same time, 49185 packs of plain cotton towels which were the total consumption quantity of our hospital in 2017 and the same quantity of disposable non-woven towers were analyzed in the cost for comparison. Results:A single pack of disposable non-woven towel was RMB 2.50 cheaper than the plain cotton towel and the use of disposable non-woven towel can save the cost of RMB 2.50 per pack. In 2017, 49185 packs of plain cotton towel were used in total, which cost RMB 122962.50 less than the same quantity of disposable non-woven towels and using the disposable non-woven towel could save RMB 122962.50 annually. Conclusion: Compared with the plain cotton towel, the non-woven shares the advantages of none flocculation, longer storage time and better antibacterial effect as well as the material, cleaning and labor costs-saving. The cost of the disposable non-woven treatment towel is lower than that of the reusable plain cotton towel. Therefore, it is recommended to use the disposable non-woven treatment towel.

An Enhanced Nonlocal Self-Similarity Technique for Fabric Defect Detection

Fabric defect detection has been an indispensable and important link in fabric production,many studies on the development of vision based automated inspection techniques have been reported.The main drawback of existing methods is that they can only inspect a particular type of fabric pattern in controlled environment.Recently,nonlocal self-similarity(NSS)based method is used for fabric defect detection.This method achieves good defect detection performance for small defects with uneven illumination,the disadvantage of NNS based method is poor for detecting linear defects.Based on this reason,we improve NSS based defect detection method by introducing a gray density function,namely an enhanced NSS(ENSS)based defect detection method.Meanwhile,mean filter is applied to smooth images and suppress noise.Experimental results prove the validity and feasibility of the proposed NLRA algorithm.

基于深度学习的纹理布匹瑕疵检测方法

布匹瑕疵检测是纺织工业中产品质量评估的关键环节,实现快速、准确、高效的布匹瑕疵检测对于提升纺织工业的产能具有重要意义.在实际布匹生产过程中,布匹瑕疵在形状、大小及数量分布上存在不平衡问题,且纹理布匹复杂的纹理信息会掩盖瑕疵的特征,加大布匹瑕疵检测难度.本文提出基于深度卷积神经网络的分类不平衡纹理布匹瑕疵检测方法(Detecting defects in imbalanced texture fabric based on deep convolutional neural network,ITF-DCNN),首先建立一种基于通道叠加的ResNet50卷积神经网络模型(ResNet50+)对布匹瑕疵特征进行优化提取;其次提出一种冗余特征过滤的特征金字塔网络(Filter-feature pyramid network,F-FPN)对特征图中的背景特征进行过滤,增强其中瑕疵特征的语义信息;最后构造针对瑕疵数量进行加权的MFL(Multi focal loss)损失函数,减轻数据集不平衡对模型的影响,降低模型对于少数类瑕疵的不敏感性.通过实验对比,提出的方法能有效提升布匹瑕疵检测的准确率及定位精度,同时降低了布匹瑕疵检测的误检率和漏检率,明显优于当前主流的布匹瑕疵检测算法.

防护口罩用改性长效聚(偏氟乙烯-三氟乙烯)压电纤维膜的制备及其性能

聚丙烯(PP)熔喷布表面自由电荷易在湿气等作用下流失,导致过滤层及口罩快速失效。针对以上问题,采用静电纺丝技术在PP熔喷布基体上制备压电聚(偏氟乙烯-三氟乙烯)(P(VDF-TrFE))纤维层,得到PP熔喷布/P(VDF-TrFE)改性过滤层。探究了纺丝工艺对压电纤维形貌和结构的影响,进一步分析了改性过滤层经过水洗、蒸汽等耐久性处理后的静电压、烟雾过滤效率和透气性的变化。结果表明:PP熔喷布/P(VDF-TrFE)改性过滤层对PM_(2.5)的过滤效率较PP熔喷布提高了25%,在进风量为85 L/min时的过滤效率提升了27.5%;经过2次水洗、紫外线照射、蒸煮消毒等方式处理后的改性过滤层,其表面电荷具有多次弯折后可再生的特点,过滤效率维持在90%,有效提高了口罩的防护效率和使用寿命,压电材料在外力作用下可产生束缚电荷,改善了过滤层负载电荷的稳定性,从而提升了口罩防护的长效性和安全性。

超低压降静电辅助PET/PVDF织造结构滤材的制备及其空气过滤性能

为攻克空气滤材高滤效低压降难以兼顾的瓶颈,进一步提高滤材的过滤性能,在导电机织滤材的研究基础上增附储电层。以聚对苯二甲酸乙二酯(PET)机织结构织物为基底,利用化学原位反应构筑结合层与导电层,而后采用静电喷涂技术构筑具有微米颗粒结构的聚偏氟乙烯(PVDF)储电层,最终获得具有超疏松结构导储结合特性的静电负载功能滤材。研究静电喷涂参数对滤材表观形貌、厚度、力学性能、电学性能、透气性的影响,并在有源静电负载条件下研究滤材的过滤性能以及积尘分布情况,基于电场模拟分析过滤机理。结果表明:随PVDF喷涂溶液质量分数提升和喷涂时间延长,在保证无细丝产生的条件下,PVDF附着量可在0~19.2μg/cm^(2)之间调整;3%喷涂质量分数、3 min的喷涂时间为最佳参数;滤材厚度、表面比电阻、顶破强力、透气率不随PVDF附着量变化而有显著变化;滤材压降也无明显变化,可维持在超低值(6.7 Pa),但对PM_(2.5)的滤效随PVDF附着量增加和电压的提高而提升,可达94.29%,品质因子高达0.43 Pa^(-1);静电辅助下,积尘量减少,可推测静电排斥为除尘机理之一,有利于提升过滤性能,延长滤料使用寿命。

异面织物基布复合过滤材料的制备及性能研究

基布作为过滤材料的支撑体,在不恶化过滤性能的前提下,还需具备良好的机械性能。本研究以异面织物作为滤料基布,制备了三种不同组织结构的基布复合过滤材料,并对复合过滤材料、基布与非织造布的力学性能、孔径和过滤性能进行了对比分析。结果表明:机织复合过滤材料的断裂强力较大,断裂伸长率较小,而异面复合过滤材料首次断裂的强力略低于机织复合过滤材料,但首次断裂后仍能保持材料结构的完整性,这是其它几种过滤材料不具备的;异面复合过滤材料的平均孔径和透气率较小,过滤效果较好。