• Fashion & Textile Research Journal
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• v.3 no.1
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• pp.25-30
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• 2001

In order to investigate the influence of thread tension on the structure of lockstitch seam, stitch tightness and seam balance ratio are measured at various tensions of needle thread and bobbin thread. The structure of lockstitch was shown in terms of skeleton stitch models to obtain quantitative analysis of stitch tightness. The balanced seam formed to the rectangu1ar stitch model under low bobbin thread tension, but the fabric tightness produced by interlaced needle and bobbin thread under high bobbin thread tension. In this paper, new equation to obtain seam balance ratio was proposed for a lockstitch seam. By using the new equation, the seam balance ratio was not affected by the stitch density and fabric thickness. In order to form the balanced seam, the ratio on tension of needle thread and bobbin thread was about 6:1~7:1 in this experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1211-1214
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• 2007

In this paper, the experimental details of the interfacial tension measurement by breaking thread method, which measures the interfacial tension between different polymer pairs, are described. The apparatus needed are a hot state, which melts the polymers, and an optical microscopy. The measured interfacial tension values are in goog agreement with the literature's values.

• Fashion & Textile Research Journal
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• v.1 no.2
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• pp.154-159
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• 1999

In this study, for different test methods of the performance of sewing threads were used to evaluate the sewability of 10 different industrial threads. Sewability evaluations related to the breakage of thread during sewing operation were investigated by seam length and fabric thickness method (Test 1), thread tension method (Test 2), strength retention method (Test 3), and backward sewing method(Test 4), and discussed. Two of the methods, Test 1 and Test 2, simulated very harsh sewing conditions which each thread could accept as an evaluation of its sewability. Core spun thread ranked with the best sewability generally and followed by air jet textured (ATY) thread. Spun thread was superior to the filament thread in sewing thread type. In general, there was a high degree of correlation in the results of Test 1 and Test 2. The order of sewing thread by sewability test 1 was polyester spun thread, cotton thread, and p/c core spun thread. The order of sewing thread by test 2 was polyester spun thread, and p/c core spun thread. Cotton threads and cotton blended threads performed better in Test 3, and ATY threads and core spun threads in Test 4.

• The Research Journal of the Costume Culture
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• v.21 no.6
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• pp.967-973
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• 2013

During high speed sewing, the needle thread is exposed to dynamic loading, short strike loading, inertia forces, friction, rubbing, force of check spring, bending, pressure, friction, impact, shock and thermal influence. The dynamic thread loading/tension alters throughout the stitch formation cycle and along its passage through the machine. The greatest tensile force occurs at the moment of stitch stretching, when the take up lever pulls for required thread length through the tension regulator. 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, which result in upto 40% loss in tensile strength of the sewing thread. This damage in the sewing thread adversely affects its processing and functional performance. In this paper, the contribution of dynamic loading, passage through needle and fabric, and bobbin thread interaction in the loss in tensile properties has been studied. It is observed that the loss in tensile properties occurs mainly due to the bobbin thread interaction. Dynamic loading due to the action of take up lever also causes substantial loss in tenacity and breaking elongation of cotton threads.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1366-1371
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• 2003

Molecular dynamics (MD) simulations are conducted to investigate the thermophysical characteristics and the stability of liquid threads for various conditions. A cylindrical thread in the simulation domain is made of Lennard-Jones molecules. The surface tension of liquid threads can be determined from local densities, local normal and transverse components of the pressure force. In order to understand the effects of thread radii on surface tensions, the Tolman equation is modified on the basis of the cylindrical coordinates for prediction of surface tensions. Surface tensions calculated from the MD simulation agree with the prediction from the modified Tolman equation. In addition, surface tensions decrease linearly with increasing system temperature. For a binary system, the surface tension decreased linearly compared to that for a pure system with increasing binary ratio of solute molecules which have relatively large value of the affinity coefficient. For a fixed binary ratio, the surface tension increased slightly with the affinity coefficient and the maximum value appear around where the affinity coefficient is 1.5 and decreased rapidly for upper value of 1.5. In addition, the critical wavelengths of perturbations are proven to be directly proportional to the equimolar dividing radii of the liquid threads.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.111-118
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• 2000

Over tightening experiments of the tension-controlled bolts are carried out and the stripping mechanism is reviewed base on the observed results. There are two modes of bolt failure due to the over tightening : one the fracture of the bolt the other the thread stripping Bifurcation between these two modes is rather delicate but it seems being related with the elastic flexibility of the bolt which depends upon the unused thread length. The fracture mode occurs in the bolts with good flexibility while the latter with bad one. According to the ISO Standard some meter coarse threads like M20 and M22 have the same pitch which causes bigger fastener to less resistance in shear and bending compared with the smaller one. however since UNC thread system adapts different pitch for different nominal diameter unified coarse threads show better stripping resistance than their corresponding meter threads.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.1-5
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• 2003

By using an approach developed to determine the torque-tension relationship for bolted joints, frictional properties of several typical bolted joints were studied experimentally. The specific property by bolted joints certify that the most significant influence of materials and bearing surface condition. Experiments on thread friction shows that prevailing torque nuts with distorted threads provide benefit for preventing self-loosening of the nut. Repeated tightening-loosening generally increases frictions in a bolted joint. It was noted that the data scatter of the experimental results of frictions in a belted joint may overshadow the influence of size. speed, and contact positions. The results from the experimental investigation will help to better design bolted joints.

• Tribology and Lubricants
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• v.29 no.5
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• pp.286-290
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• 2013

When a threaded fastener is tightened, the torque-tension relationship is highly sensitive to two friction components: thread friction and head friction. In this study, we carried out friction experiments and analyses to determine the optimum clamping torque setting for bolt joints. First, we measured the coefficients of thread friction and head friction under the same running conditions of the bolt clamping process for lubricated and non-lubricated bolts. We also measured axial tension through bolt clamping tests using lubricated and non-lubricated bolts attached to a strain gauge. Finally, we compared the experiment and theoretical results.

• Journal of the Korean Society of Costume
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• v.52 no.5
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• pp.145-154
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• 2002

1. The blended tabby whose warp and weft each employs a different kind of thread had been weaved since the era of the Three Kingdoms in this nation and since the period of Han in China. Especially in the 15th century. very finely weaved fabrics as the specialty of Chosun were exported to China. In the 16th century. blended tabby weaved with silk and cotton were often used for clothes as cotton was produced around the nation. And in the 17th century. blended tabby employing high quality Chinese raw silk other than existing ones were weaved. 2. It has been found in literature review that Honpo, one of Chosun's blended tabby. was manufactured mainly in Hamkyung, Cholla and Kyungsang provinces and mostly distributed through markets of Chungchong and Cholla provinces. 3. Out of the total 19 fabric pieces. 13 employed silk thread as the warp and cotton thread as the weft. Compared with the weft. in general. the warp is given more tension when weaved and more friction by spindles, being more likely to be twisted than the weft. In addition to starching, a stronger thread is requested as the warp. It is natural that in the Chosun period, silk thread more stronger than cotton thread was used as the warp to make more durable fabrics. For the weft requiring lots of threads when weaved. cotton thread was mainly used in the 17th century because the thread could be easily obtained at that time. 4. So far the study has made an empirical review of Chosun's blended tabby. especially those of the 15th∼17th century, in terms of their production and distribution. Findings from the study have some limit because they have been made focusing on the 15th∼17th century not the whole period of Chosun. Therefore it is needed to complement those findings through further studies.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.1
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• pp.43-50
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• 2010

The 200mesh screen was tensioned and fixed on a frame. When applied tension to 5N and 10N per unit area, a side length of opening of the screen was 163.223${\mu}m$ and 168.224${\mu}m$, respective. But side length not tensioned was 158.879${\mu}m$. We knew that a side length of opening of the screen rarely changes with tension applied to the screen. The appearances that a side length of opening of the screen expand little are due to a decreasing diameter of thread by means of tension. In a thickness measurement of screen, While the high density mesh screen that had a lot of knots that crossed a line of latitude and longitude per unit area appeared a higher numerical value, the low density mesh screen that had a few knots appeared a low numerical value.