Effect of single yarn twist and ply to single yarn twist ratio on strength and elongation of ply yarns

2005 ◽  
Vol 98 (5) ◽  
pp. 2245-2252 ◽  
Author(s):  
N. K. Palaniswamy ◽  
A. Peer Mohamed
Keyword(s):  
Yarn Twist ◽  
Twist Ratio ◽  
Single Yarn

scholarly journals Chemical and physical interactions of regenerated cellulose yarns and isocyanate-based matrix systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bernhard Ungerer ◽  
Ulrich Müller ◽  
Antje Potthast ◽  
Enrique Herrero Acero ◽  
Stefan Veigel
Keyword(s):  
Mechanical Performance ◽  
Tensile Force ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Size Exclusion ◽  
Regenerated Cellulose ◽  
Hydrolytic Cleavage ◽  
Yarn Twist ◽  
Exclusion Chromatography ◽  
Physical And Chemical

AbstractIn the development of structural composites based on regenerated cellulose filaments, the physical and chemical interactions at the fibre-matrix interphase need to be fully understood. In the present study, continuous yarns and filaments of viscose (rayon) were treated with either polymeric diphenylmethane diisocyanate (pMDI) or a pMDI-based hardener for polyurethane resins. The effect of isocyanate treatment on mechanical yarn properties was evaluated in tensile tests. A significant decrease in tensile modulus, tensile force and elongation at break was found for treated samples. As revealed by size exclusion chromatography, isocyanate treatment resulted in a significantly reduced molecular weight of cellulose, presumably owing to hydrolytic cleavage caused by hydrochloric acid occurring as an impurity in pMDI. Yarn twist, fibre moisture content and, most significantly, the chemical composition of the isocyanate matrix were identified as critical process parameters strongly affecting the extent of reduction in mechanical performance. To cope with the problem of degradative reactions an additional step using calcium carbonate to trap hydrogen ions is proposed.

Analyzing the Effect of Fiber, Yarn and Fabric Variables on Bagging Behavior of Single Jersey Weft Knitted Fabrics

2013 ◽  
Vol 8 (3) ◽  
pp. 155892501300800 ◽  
Author(s):  
Mitra Karimian ◽  
Hossein Hasani ◽  
Saeed Ajeli
Keyword(s):  
Optimum Process ◽  
Process Conditions ◽  
Knitted Fabrics ◽  
Yarn Twist ◽  
Fabric Density ◽  
Fabric Structure ◽  
Controllable Factors ◽  
Yarn Count ◽  
The Individual ◽  
Single Jersey

This research investigates the effect of fiber, yarn and fabric variables on the bagging behavior of single jersey weft knitted fabrics interpreted in terms of bagging fatigue percentage. In order to estimate the optimum process conditions and to examine the individual effects of each controllable factor on a particular response, Taguchi's experimental design was used. The controllable factors considered in this research are blending ratio, yarn twist and count, fabric structure and fabric density. The findings show that fabric structure has the largest effect on the fabric bagging. Factor yarn twist is second and is followed by fabric density, blend ratio and yarn count. The optimum conditions to achieve the least bagging fatigue ratio were determined.

Estimation of yarn strength based on critical slipping length and fiber length distribution

2017 ◽  
Vol 89 (2) ◽  
pp. 182-194 ◽  
Author(s):  
Zhan Jiang ◽  
Chongwen Yu ◽  
Jianping Yang ◽  
Guangting Han ◽  
Mingjie Xing
Keyword(s):  
Fiber Length ◽  
Length Distribution ◽  
Probability Method ◽  
Yarn Strength ◽  
Fiber Length Distribution ◽  
Yarn Twist ◽  
Twist Multiplier ◽  
Strength Based ◽  
Breaking Mechanism ◽  
Yarn Structure

Yarn strength is composed of the total contributions made by all breaking and slipping fibers which are determined by critical slipping length lc. Though the definition of lc has been the focus of many research projects, it still remains unsolved. In this study, idealized assumptions were made on yarn structure, and lc was then estimated. At the same time, the actual contributions that breaking fibers and slipping fibers make to yarn strength were recalculated based on an idealized yarn structure, which was analyzed with the conditional probability method according to fiber length distribution. Then, yarn strength was computed by simulating random fiber arrangement in the yarn. It could be seen from calculated results that the critical slipping length declines as yarn twist multiplier increases. Meanwhile, as the twist multiplier increases, the calculated yarn strength rises to the highest point and then declines, which is in agreement with traditional spinning theory. Thus, the calculation of yarn strength based on critical slipping length could reflect the yarn breaking mechanism with a change in the yarn twist multiplier, and could be applied for further prediction of yarn strength.

scholarly journals Structure of Novel Composite Single Yarn from Polypropylene Staple Fibers

2012 ◽  
Vol 58 (3) ◽  
pp. 27-34 ◽  
Author(s):  
Hirokazu KIMURA ◽  
Masakazu MATSUMOTO ◽  
Yo-ichi MATSUMOTO ◽  
Kazunari FUKUSHIMA
Keyword(s):  
Single Yarn

Characterization of Polypropylene Staple Yarns by Acoustic Dynamic Modulus

2013 ◽  
Vol 586 ◽  
pp. 3-7
Author(s):  
Dana Kremenakova ◽  
Jiří Militký ◽  
Juan Huang
Keyword(s):  
Dynamic Modulus ◽  
Pulse Propagation ◽  
Tensile Modulus ◽  
Polypropylene Fibers ◽  
Orientation Factor ◽  
Cross Sectional ◽  
Indirect Measure ◽  
Yarn Twist ◽  
Propagation Technique

The acoustic or sonic pulse-propagation technique for the measurement of dynamic elastic modulus has the advantage of not being dependent on the sample cross-sectional characteristics. This technique also gives a direct measure of modulus rather than the indirect measure in the form of load versus extension. The sonic tests are relatively simple to apply and are nondestructive. The values of sonic modulus of fibrous structures are dependent on the orientation of components and packing density as well. The main aim of this work is to quantify effect of yarn twist on the sonic modulus of staple yarns from polypropylene fibers. The results are compared with selected models of yarn twist influence on the mechanical properties of staple yarns. The correlation between yarn orientation factor defined by Pan and sonic modulus are shown. The sonic modulus is compared with tensile modulus of yarns.

scholarly journals Evidence for abnormal deformational reserve in hypertrophic obstructive cardiomyopathy on exercise: is this a true fingerprint?

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
L Halmai ◽  
M Ward ◽  
A Kardos ◽  
A Nemes ◽  
S Neubauer ◽  
...  
Keyword(s):  
Valsalva Maneuver ◽  
Coupling Efficiency ◽  
Inverse Correlation ◽  
Hypertrophic Obstructive Cardiomyopathy ◽  
University Hospital ◽  
Funding Source ◽  
Peak Strain ◽  
Additional Information ◽  
Control Subjects ◽  
Twist Ratio

Abstract   Hypertrophic obstructive cardiomyopathy (HOCM) is characterized by muscle hypertrophy and fibrosis, interfering with force generation and relaxation. Abnormal ventricular (LV) myocardial deformation have been demonstrated in patients with HOCM at rest, but there is lack of data regarding the deformational mechanics in exercise in obstructive HCM. Aims To assess the adaptability of LV deformational behaviour to physical exercise in HOCM patients as compared to healthy controls and to examine if Deformational Imaging (DMI) can provide additional information. Methods 28 obstructive HOCM (age 51.2±14.2yrs; 16 men, LVOT-obstruction 56±19mmHg at rest or on Valsalva maneuver) and 32 control subjects (50.9±6.8 yrs, 19 men from the MAGYAR-PATH Registry) underwent bicycle stress Echo (ESE) with full conventional 2D- and Doppler TTE, 2D- and 3D-Speckle Tracking Analysis (DMI) and 3D-Full Volume assessment both at rest and on submaximal ESE. Results At rest, the HOCM group had lower GLS (−14.6±4.5 vs 18.4±2.6%, p<0.01) but higher CS (−32.9±5.1 vs 28.8±2.3%) and Twist (9.9±2.6 vs 6.1±2.2°) than in control subjects. Exercise induced an increase in all strains in control subjects but less in HOCM (GLS: −21.4±3.5 vs 15.1±3.0% and CS: −33.9±3.6 vs 34.1±4.2% in controls). The increase of LV twist was blunted in HOCM (Δ1.2 vs Δ3.6° in controls). The PSS was more pronounced in HOCM on ESE (46.6±12.0 vs 21.2±9.6%, AUC: 0.71 for predicting HOCM), the UTR was slower (118±2.1 vs 133.1±14.1°/s) and occurred later in HOCM. The MD of Strain increased in HOCM on ESE (Δ85.1 vs Δ8.1ms in controls). The Twist had positive correlation with LVOT-obstruction (R2=0.54, p<0.01) and inverse correlation with UTR (R2=−0.72, p<0.02). The UTR/Twist ratio diminished only in HOCM on exercise (−6.0±0.8 vs −13.1±2.5 1/s). The MD, the PSS on ESE and the UTR/Twist ratio predicted the HOCM deformation phenotype accurately (AUC: 0.72, cut-off 6.0 1/s). Conclusions The HOCM patients had attenuated Strain and Rotational response on exercise implying impaired deformational adaptability with post-systolic shortening and pronounced mechanical dispersion of peak Strain on exercise which was more accurate to identify the HOCM phenotype than other Echo-indices. These findings support evidence for reduced systolic-diastolic coupling efficiency in HOCM patients on exercise which can contribute to the development of exercise-related breathlessness, dynamic LVOT-obstruction and arrhythmias in patients with HOCM. These distinct deformational patterns on exercise can help in the differential diagnosis of patients with LV hypertrophy of unknown aetiology with good sensitivity and specificity and can also aid in the risk stratification workup in HOCM. DMI Predictors for HOCM Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Milton Keynes University Hospital Research Founding

Effect of fiber friction, yarn twist, and splicing air pressure on yarn splicing performance

2005 ◽  
Vol 6 (1) ◽  
pp. 72-78 ◽  
Author(s):  
A. Das ◽  
S. M. Ishtiaque ◽  
Jyoti R. Parida
Keyword(s):  
Air Pressure ◽  
Yarn Twist
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