scholarly journals Effect of Workwear Fabric Characteristics on the Changes in Tensile Properties of Sewing Threads after Sewing

2010 ◽  
Vol 5 (1) ◽  
pp. 155892501000500 ◽  
Author(s):  
Vinay Kumar Midha ◽  
V. K. Kothari ◽  
R. Chattopadhyay ◽  
A. Mukhopadhyay
Keyword(s):  
Cotton Fabric ◽  
Strength Loss ◽  
Breaking Elongation ◽  
Cotton Thread ◽  
Increase With Increase ◽  
Initial Modulus ◽  
Thread Strength ◽  
Fabric Weight ◽  
The Impact ◽  
Needle Thread

During sewing at high speed, the needle thread is subjected to repeated tensile stresses, heat, bending, pressure, torsion and wearing. These stresses act on the thread repeatedly and the thread passes 50–80 times through the fabric, the needle eye and the bobbin case mechanism, before getting incorporated into the seam. As a result both the sewing thread and the yarns in the fabric get abraded/ severed during the seaming process. A number of researchers observed that there could be 30% to 40% strength loss in the cotton needle thread after sewing. The extent of damage becomes more critical if the fabric being used is of a dense, thick and heavy construction. A number of studies have been carried out on thread strength loss after sewing, but the impact of fabric characteristics on thread strength loss is still unexplored. In this paper, the effect of weight and fabric composition of workwear fabrics, on the changes in the tenacity, breaking elongation and initial modulus of the needle thread has been studied. The tenacity and breaking elongation loss increase with increase in fabric weight for staple threads and remain unchanged for core spun threads. The loss in initial modulus increases for polyester threads as fabric weight increases, and decreases for cotton thread. When sewn on polyester-cotton fabric of same weight, the cotton thread shows decrease in tenacity and breaking elongation loss, whereas loss in initial modulus increases. The polyester core spun threads show exactly opposite change, i.e. tenacity and elongation loss increase and loss in initial modulus decreases when sewn on polyester-cotton fabric.

An Approach to Seam Strength Prediction Using Residual Thread Strength

2011 ◽  
Vol 15 (3) ◽  
pp. 75-85 ◽  
Author(s):  
Vinay Kumar Midha ◽  
A Mukhopadhyay ◽  
Ramanpreet Kaur
Keyword(s):  
Process Parameters ◽  
Significant Influence ◽  
Strength Loss ◽  
Strength Prediction ◽  
Predictive Equations ◽  
Substantial Loss ◽  
Stitch Density ◽  
Fabric Strength ◽  
Thread Strength ◽  
Needle Thread

Owing to a high amount of stress, seam failure in workwear fabrics makes the fabric unsuitable although the fabric strength is high. It is therefore important to predict the seam strength to ascertain the performance of the garments during use and determine the required thread strength and stitch density to match the required seam strength. In all of the earlier predictive equations, seam strength is predicted from thread strength and stitch density along with some multiplicative factors. During the sewing process, a substantial loss in needle thread strength occurs; therefore, the thread becomes weaker than expected after incorporation into the seam. In this paper, the effects of various machine and process parameters are studied on thread strength loss and seam strength. The seam strength is predicted from the loop strength after considering the loss in thread strength. It is observed that higher seam strengths are observed when stronger threads are used for sewing. Loss in thread strength has a significant influence on the seam strength. Seam strength can be predicted using stitch density and thread loop strength, by considering the loss in thread strength during the sewing process. A closer match between predicted and experimental seam strength is possible.

Does kraft hardwood and softwood pulp viscosity correlate to paper properties?

TAPPI Journal ◽  
2016 ◽  
Vol 15 (10) ◽  
pp. 643-651 ◽  
Author(s):  
ROBERT J. OGLESBY ◽  
HUMPHREY J. MOYNIHAN ◽  
RICARDO B. SANTOS ◽  
ASHOK GHOSH ◽  
PETER W. HART
Keyword(s):  
Physical Properties ◽  
Strength Loss ◽  
Strength Properties ◽  
Clear Correlation ◽  
Paper Properties ◽  
Physical Strength ◽  
Pulp Viscosity ◽  
Softwood Pulp ◽  
The Impact ◽  
Related Paper

The impact of commercially prepared, fully bleached pulp viscosity variation on handsheet physical properties was evaluated at different levels of pulp refining. Hardwood pulps from the same brownstock species mix, cooking parameters, and kappa numbers were processed through two different commercial bleach plants: one with a D0(EP)D1D2 sequence and the second with an OD0(EOP)D1 sequence. Additionally, a commercial softwood (predominately Scotts pine) brownstock pulp bleached by an OD0(EP)D1D2 sequence was employed in this study. Pulps with viscosities ranging from 14 to 21 mPa∙s were refined in a Valley beater to two freeness levels, and the associated handsheet physical properties were measured in this study. Over the pulp viscosity range of 14 to 21 mPa∙s, no clear correlation was found to exist between pulp viscosity and related paper physical properties. Finally, a series of laboratory prepared bleached pulps were purposely prepared under non-ideal conditions to reduce their final viscosities to lower values. Handsheets made from these pulps were tested in their unbeaten condition for physical strength properties. Significant and rapid strength loss occurred when the measured pulp viscosity dropped below 12 mPa∙s; overall strength properties showed no correlation to viscosity above the critical 12 mPa∙s value.

Study on the Enzyme Desizing Process for Cotton Fabric Using Ultrasonication

2011 ◽  
Vol 331 ◽  
pp. 261-264 ◽  
Author(s):  
Qi Ming Zhao ◽  
Shan Yan Zhang
Keyword(s):  
Cotton Fabric ◽  
Ph Value ◽  
Orthogonal Experiment ◽  
Research Result ◽  
Strength Loss ◽  
Cotton Fabrics ◽  
Optimum Process ◽  
Process Conditions ◽  
Fabric Strength ◽  
Enzyme Dosage

The auxiliary devices of ultrasonic treatment was designed and manufactured. The cotton fabric was desized using 2000L desizing enzyme with the conventional enzyme desizing process and ultrasonic enzyme desizing process respectively. Through the orthogonal experiment, the optimum process conditions of conventional enzyme desizing process and ultrasonic enzyme desizing process were determined. For the conventional enzyme desizing process, the optimized desizing conditions of cotton fabrics were: desizing enzyme dosage was 1.5g/l, temperature was 80°C, PH value was 6, and time was 60mins. The optimum process conditions of ultrasonic enzyme desizing process were: desizing enzyme dosage was 1.5g/l, temperature was 50°C, PH value was 6 and time was 45minutes. The research result indicates that, under the same desizing condition, ultrasonication can improve the desizing percentage and whiteness of cotton fabric, but the fabric strength loss increases slightly. And for the same required desizing percentage, the ultrasonic enzyme desizing process saved time and reduced the temperature of experiments compared with traditional enzyme desizing process

Strength Loss in Composite Cylinders Under Impact

1988 ◽  
Vol 110 (2) ◽  
pp. 180-184 ◽  
Author(s):  
A. P. Christoforou ◽  
S. R. Swanson
Keyword(s):  
Composite Structures ◽  
Composite Plates ◽  
Strength Loss ◽  
Pressure Vessels ◽  
Fourier Series Expansion ◽  
Lateral Impact ◽  
Low Velocity ◽  
Expansion Procedure ◽  
The Impact ◽  
Composite Cylinders

The problem of strength loss in composite structures due to impact appears to be important due to the sensitivity of advanced composites to these loadings. Although a number of studies have been carried out on impact of flat composite plates, relatively little work has been done on tubular geometries such as pressure vessels despite the usage in applications. We have addressed the problem of calculating strength loss due to low velocity, lateral impact of composite cylinders. In our model we use an existing Fourier Series expansion procedure to calculate ply stresses and strains, compare these values with allowables to predict fiber breakage during the impact, and finally use fracture mechanics to predict the strength loss due to the impact. Although the model is quite simplified, the general trends of experiments appear to be represented.

scholarly journals Effect of Polypropylene Fiber on Frost Resistance of Cemented Soil

2019 ◽  
Vol 57 (2) ◽  
pp. 78-86
Author(s):  
Lina Xu ◽  
Lei Niu
Keyword(s):  
Frost Resistance ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Strength Loss ◽  
Curing Time ◽  
Freezing And Thawing ◽  
Cemented Soil ◽  
Small Cracks ◽  
The Impact ◽  
Engineering Projects

Polypropylene fiber is widely used as a reinforcing material in composite materials of various engineering projects, because it has high strength and corrosion resistance. In this study, with the purpose of examine the impact of discrete polypropylene fiber on frost resistance of cemented soil, cemented soil treated with polypropylene fiber is used as the research sample. Firstly, the impact of curing time, fiber content and length on the strength of cemented soil has been considered. And then, the frost resistance characteristics of cemented soil reinforced by polypropylene fiber with the content of 0.5% have been investigated. The results show that with the development of curing time, the strength of cemented soil increases logarithmically. By adding an appropriate amount of polypropylene fiber, the strength of the specimen may be improved. In this study, cemented soil reinforced by polypropylene fiber 0.1% in content and 3 mm in length has the best reinforcement effect. After 21 cycles of freezing and thawing processes, a sharp decline in strength of cemented soil without fiber, and the strength loss ratio is up to 45%. There are cracks in the specimens, and some of the specimens have broken off. Differently, after 21 freeze-thaw cycles, the strength of the cemented soil with fiber decreased less, and the strength loss ratios are between 1 and 13%, and there are only small cracks on the surface of specimens. The results show that adding discrete polypropylene fiber is a suitable method to prevent the generation and development of internal cracks in the cemented soil during freezing and thawing, thereby improving the frost resistance. These results can be used as a reference for the application of cemented soil reinforced with fiber in seasonal frozen regions.

scholarly journals Fire Performance of Columns Made of Normal and High Strength Concrete: A Comparative Analysis

2016 ◽  
Vol 711 ◽  
pp. 564-571 ◽  
Author(s):  
Thomas Gernay
Keyword(s):  
Bearing Capacity ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Strength Loss ◽  
Fire Performance ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Strength Concrete ◽  
The Impact

The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.

Scouring Cotton Fabric by Water-Extracted Substance from Soap Nut Fruits and Licorice

2014 ◽  
Vol 535 ◽  
pp. 768-771 ◽  
Author(s):  
Antika Noochuay ◽  
Porntip Sae-Bae ◽  
Pimpawan Kumphai ◽  
Siwipha Suangtho
Keyword(s):  
Surface Tension ◽  
Cotton Fabric ◽  
Wetting Agent ◽  
Licorice Root ◽  
Scouring Process ◽  
Fabric Weight

This study used water to extract substances from hulls of soap nut fruits (Sapindus Emarginatus) and licorice root (Glycyrrhizaglabra L.) found in Thailand to remove waxes in cotton scouring process. CMC value from soap nut fruits were found to be 6 mg/ml with surface tension of 54.67 mN/m and can be used as wetting agent when the temperature is lower than 70 °C. CMC value from licorice root was 10 mg/ml with surface tension of 51.50 mN/m and can be used as wetting agent at temperature higher than 95°C. The results exhibited that both substances can be used to remove waxes in cotton scouring process. At the 40% of substance powder by fabric weight, the cotton fabric absorbed water in 5 seconds.

Study on Properties about Bamboo Yarns

2011 ◽  
Vol 332-334 ◽  
pp. 45-48 ◽  
Author(s):  
Lin Tian ◽  
Lei Tan ◽  
Qing Bin Yang
Keyword(s):  
Tensile Strength ◽  
Abrasion Resistance ◽  
Moisture Absorption ◽  
Abrasive Resistance ◽  
Breaking Elongation ◽  
Initial Modulus ◽  
Cotton Yarns

In order to understand the basic performances of bamboo yarns, the tensile strength, abrasion resistance and hairiness of yarns are analyzed through the comparison of bamboo yarns, cotton yarns and ramie yarns. Bamboo yarns show a higher strength, a lower breaking elongation, a better abrasive resistance and an obvious hairiness. Because of the existence of uneven fineness, the strength of bamboo yarns display a higher level of unevenness than cotton yarns and ramie yarns. After moisture absorption, the strength, initial modulus and work to break will increase remarkably.

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