共查询到10条相似文献，搜索用时 120 毫秒
1.
Ali Afzal Tanveer Hussain Mumtaz Hassan Malik Abher Rasheed Sheraz Ahmad Abdul Basit Ahsan Nazir 《Fibers and Polymers》2014,15(7):1539-1547
The aim of this study was to analyze and model the effect of knitting parameters on the air permeability of Cotton/Polyester double layer interlock knitted fabrics. Fabric samples of areal densities ranging from 315–488 g/m2 were knitted using yarns of three different cotton/polyester blends, each of two different linear densities by systematically varying knitting loop lengths for achieving different cover factors. It was found that by changing the polyester content in the inner and outer fabric layer from 52 to 65 % in the double layer knitted fabric did not have statistically significant effect on the fabric air permeability. Air permeability sharply increased with increase in knitting loop length owing to decrease in fabric areal density. Decrease in yarn linear density (tex) resulted in increase in air permeability due to decrease in areal density as well as the fabric thickness. It was concluded that response surface regression modeling could adequately model the effect of knitting parameters on the double layer knitted fabric air permeability. The model was validated by unseen data set and it was found that the actual and predicted values were in good agreement with each other with less than 10 % absolute error. Sensitivity analysis was also performed to find out the relative contribution of each input parameter on the air permeability of the double layer interlock knitted fabrics. 相似文献
2.
This study focused on the fabrication and acoustic property evaluation of sandwich cover-ply-reinforced highresilience thermal-bonding nonwoven hybrid composites. P-phenyleneterephthalamides and bicomponent high-resilience bonding polyester intra-ply hybrid nonwoven fabrics were compounded with glass plain fabric to produce the high strength sandwich structural cover ply by means of needle punching and thermal bonding to reinforce the whole composites and dissipate energy when being impacted. Then, the acoustic absorption properties of the homogenous intra-ply hybrid meshwork layer were investigated before and after being reinforced with the aforementioned cover ply. The influencing factors, including areal density, fiber blending ratio, needle punching depth, and air cavity thickness between back plate of the impedance tube and composites, were comparatively investigated. Results revealed that hybrid composites exhibited exceedingly high acoustic absorption properties. Acoustic absorption coefficients were promoted with increases in areal densities and fiber blending ratio of 3D crimped hollow polyester, particularly at low-mid frequency range. In addition, needle punching depths and back air cavity thicknesses considerably affected the average absorption coefficients. The meshwork center layer reinforced with sandwich structural cover-ply perform high resilience properties. 相似文献
3.
In the results from a previously reported uniformity trial on pasture evaluation, there appeared to be systematic areal changes in the crude fibre and crude protein percentages of the herbage. These trends have been illustrated by the calculation of quadratic contours and the possible relationships of the changes to local soil differences, moisture percentages and copse shelter effects have been investigated. 相似文献
4.
Authors studied on the applicability of image analysis technique using a scanner with a CCD (charged coupled deviced) to the
evaluation of evenness of nonwovens because it has distinctive features to considerably save time and labor in the analysis
compared with other classical methods. As specimens for the experiment, two different types that are unpatterned and patterned
ones were prepared. For the unpatterned specimen, webs were chermically bonded, while for the patterned specimen, webs being
thermally calendered with engraved roller. Several webs having various areal densities were prepared and bonded. Coefficient
of variation (CV%) was used as a parameter to evaluate the evenness. Scanning conditions could be suitably set up through
comparing the total variance to the between-group variance and to the within-group variance, respectively, on the images scanned
at the different conditions. The 2D convolution method with smoothing filter kernel was introduced to further filter the noises
on the scanned images. After the filtering process, the increase of web areal densities gave an uniform decrease of the CV%.
This showed that the scanned image analysis with proper filtering process could be successfully applicable to the evaluation
of evenness in nonwovens. 相似文献
5.
Omid Saligheh Reza Eslami-Farsani Ramin Khajavi Mahdi Forouharshad 《Fibers and Polymers》2013,14(11):1864-1869
In this study, the effect of processing parameters such as temperature, pressure, time of compaction process and areal density on high-velocity impact behaviour of high performance polyethylene fibre cross-ply composites were investigated by Taguchi method. Samples were made through high temperature and pressure compacting process and morphology and interlayer adhesive of samples were investigated by scanning electron microscopy “SEM and T-peel test, repectively. Taguchi method was used to plan a minimum number of experiments. Statistical analysis, analysis of variance (ANOVA), was also employed to determine the relationship between experimental conditions and yield levels. ANOVA was applied to calculate sum of square, variance, ratio of factors variance to error variance and contribution percentage of each factors on response. A hemispherical tip type projectile was used for high velocity impact tests and the depth of trauma as the response factor was measured after impacting test. Results showed that when the temperature, pressure, and time of compacting process were 125 °C, 3 MPa, and 30 min for the composite sample with 7.4 kg/m2 areal density, the trauma depth was decreased to its lowest value. 相似文献
6.
It has been shown through various experimental works that the geometry of woven fabrics will change after it is released from looms due to the contraction forces resulting in changed structural geometry in their fully relaxed state. In this work, an appropriate three dimensional unit cell is proposed for 2/2 twill woven structure. The proposed model covers all angles and lengths between warp and weft yarns in the three dimensional unit cell of the structure in its fully relaxed state assuming straight line path and circular cross-section of yarns. At first, a theoretical solution for estimation of skewness angle in float region of 2/2 twill fabrics is proposed by defining the JJ ratio index to consider different amount of contraction in float and crimp region of unit cell. Then the proposed theory is extended to include the weave and skewness angle of yarns in crimp region of woven structures. By applying this theory, the skewness angle of 2/2 twill weaves will be incorporated in structural modelling of woven fabrics which can be used in predicting the thickness and areal mass of the 2/2 twill woven structures. Besides the confirmed validation of model in predicting the areal mass, the results for estimating the thickness of fabrics are in close agreement with the measured ones in the fabrics with worsted and coarse cotton yarns. 相似文献
7.
Yong Yang Binbin Li Zhaofeng Chen Muhammad Umar Saeed Zhou Chen Chengdong Li Cao Wu Yufang Li Renli Fu 《Fibers and Polymers》2016,17(1):97-103
This paper presents the effect of cross-sectional morphologies and composite structures of glass fiber felts on their corresponding acoustic properties. Glass fiber felts with random and layered cross-sectional structure are produced by centrifugal-spinneret-blow system. Acoustic properties are determined by a B&K impedance tube. The results show that sound transmission loss (STL) of glass fiber felts with layered cross-sectional structure exhibit greater than that with random cross-sectional structure. However, there is a little difference between the absorption coefficient values for random and layered cross-section. It means that glass fiber felts with layered cross-section are better to improve the sound insulation. With the increase of thickness, STLs of glass fiber felts with the same areal density do not increase monotonically due to the changing of porosity and characteristic impedances. Different glass fiber felts with layered cross-sectional structure are combined to form a variety of composite structures. It finds that assembly order of glass fiber felts have an effect on the total sound insulation. The large mismatch between the acoustic impedances causes multiple reflections leading to the best STL. 相似文献
8.
In the large-scale irrigation schemes of the lower Ili River Basin of Kazakhstan, crop rotation combines paddy rice and non-rice crops. Continuous irrigation is practiced in paddy fields, whereas other crops are sustained from groundwater after only limited early irrigation. The water table in non-rice crops is raised by seepage from canals and the flooded paddy fields. We investigated the areal extent to which the groundwater level of non-irrigated fields is influenced by seepage from canals and paddy fields by examining the relationship between distance (from canal and paddy field) and groundwater level in upland fields. The groundwater level was influenced for up to 300 and 400 m from the canals and paddy fields, respectively. Geographic information system analysis of crop and canal patterns in the 11 selected years showed that if the zone of influence is 300 and 400 m from the canals and paddy fields, respectively, the groundwater level of most of the area of upland fields was raised by seepage. We conclude that the water supply to cropping fields by seepage from irrigation canals and paddy fields is adequate, but the spatial distribution of the paddy fields may be an important factor that needs more attention to help improve water use efficiency in this irrigation district. 相似文献
9.
C. N. Herath 《Fibers and Polymers》2013,14(8):1339-1346
In this research work, air permeability variations of core spun cotton/spandex single jersey and 1×1 rib knitted structures were studied under relaxation treatments. Results are compared with similar fabrics made from 100 % cotton material. Even though cotton/spandex fabrics knitted with same stitch lengths, their structural spacing and stitch densities vary with the progression of treatments. Similar behavior was also observed with 100 % cotton knitted structures. Under higher machine set stitch lengths (i.e., lower fabric tightness factor), higher structural spacing and lower stitch densities were resulted and those variations significantly affected on the air permeability variations of knitted structures. 1×1 rib knitted structures showed significantly higher air permeability than single jersey structures and it is more prominent with cotton rib structures. However, cotton/spandex 1×1 rib and single jersey structures have not showed such significant deviations. Air permeability of cotton/spandex and 100 % cotton rib and single jersey knitted structures decreased with lower machine set stitch lengths (i.e., at higher fabric tightness factors). There was a correlation with fabric tightness, air permeability, areal density and fabric thickness such as knitted fabrics became tighter, their weight and thickness were higher, while their air permeability was lower. Thus, fabric areal density and fabric thickness are positively correlates to machine set stitch length?1 (fabric tightness factor). Air permeability of a knitted structure depends on material type, knitted structure, stitch length, relaxation treatment, structural spacing and stitch density. 相似文献
10.
The investigation of the shear behaviour of technical natural fibres is vital for the insurance of aesthetics and performance of light weight, high strength, and eco-friendly composites. In this study, Egyptian jute fibre plain weave fabrics of various areal densities were investigated to describe their shear behaviour in terms of shear forces, shear angles and shear lock angles, using the Bias-Extension and the Picture Frame test methods. Results show that both methods are valid for natural fibres and produce comparable results. Whereas the Bias-Extension test presents a fast and simple test procedure, the analysis of the results is more complex due to the interaction of non-shear components. On the other hand, the Picture Frame test proves to be time consuming and in need of a more complex test rig, but results in pure shear deformations throughout the sample. 相似文献