• Fibers and Polymers
• /
• 제6권1호
• /
• pp.72-78
• /
• 2005

The impact of fiber friction, yarn twist, and splicing air pressure on mechanical and structural properties of spliced portion have been reported in the present paper. The mechanical properties include the tensile and bending related properties and, in the structural properties, the diameter and packing density of the splices are studied. A three variable three level facto­rial design approach proposed by Box and Behnken has been used to design the experiment. The results indicate that there is a strong correlation between retained spliced strength (RSS) and retained splice elongation (RSE) with all the experimental variables. It has been observed that RSS increases with the increase in splice air pressure and after certain level it drops, whereas it consistently increases with the increase in yarn twist. The RSE increases with the increase in both fiber friction and yarn twist. It has also been observed that the yarn twist and splicing air pressure have significant influence on splice diameter, percent increase in diameter and retained packing coefficient, but the fiber friction has negligible influence on these parame­ters. Yarn twist and splicing air pressure has a strong correlation with splice flexural rigidity, where as poor correlation with retained flexural rigidity.

• 한국의류산업학회지
• /
• 제1권2호
• /
• pp.166-172
• /
• 1999

An experimental investigation has done for studying the changes of physical properties of the air-jet textured polyester yarn. Through the experiments of polyester 85/72 drawn yarn and 50/36 partially oriented yarn doubling' the following results are obtained. The tenacity of textured yarn decreased as the number of tension rings increased when the nozzle diameter was 1.2 mm. In the case when the tension ring was not used during the texturing process, the tenacity of textured yarn decreased as the nozzle diameter increased. But this tendency changed according to the number of tension rings used, the diameter of the nozzle, and yarn take-up speed. Breaking elongation decreased as the number of tension rings increased from one to four and the take-up speed increased at diameter 1.2 mm of the nozzle. The higher the diameter of the the nozzle the higher the breaking elongation until 1.4 mm. The number of interlacing went down as the diameter of the nozzle increased and the take-up speed of the yarn increased. The higher the number of tension rings, the lower the number of interlacing.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.433-433
• /
• 2016

Carbon nanotubes (CNT) emitter has widely become an attractive mechanism that draws growing interests for cold cathode field emission. CNT yarns have demonstrated its potential as excellent field emitters. It was demonstrated that a small focal spot size was achieved by manipulating some electrical parameters, such as applied bias voltage at the mesh gate, and electrostatic focal lenses, geometrical parameters, such as axial distances of the anode, and the electrostatic focal lens from the cathode assembly, and the dimension of the opening of the electrostatic lens. Electrical-optics software was used to systematically investigate the behavior of the electron beam trajectory when the aforementioned variables were manipulated. The results of the experiment agree with the theoretical simulation results. Each variable has an individual effect on the electron beam focal spot size impinging on the target anode. An optimum condition of the parameters was obtained producing good quality of X-ray images. Also, MWCNT yarn was investigated for field emission characteristics and its contribution in the X-ray generation. The dry spinning method was used to fabricate MWCNT yarn from super MWCNTs, which was fabricated by MW-PECVD. The MWCNT yarn has a significant field emission capability in both diode and the triode X-ray generation structure compared to a MWCNT. The low-voltage-field emission of the MWCNT yarn can be attributed to the field enhancing effect of the yarn due to its shape and the contribution of the high-aspect-ratio nanotubes that protrude from the sides of the yarn. Observations of the use of filters on the development of X-ray images were also demonstrated. The amount of exposure time of the samples to the X-ray was also manipulated. The MWCNT yarn can be a good candidate for use in the low voltage field emission application of X-ray imaging.

• 복식
• /
• 제58권10호
• /
• pp.65-77
• /
• 2008

The purpose of this study is to analyze the correlation between the density, the Count and the width of cross section in 2D function through comparison the difference of simulated fabrics based on the various yarns, and to compare the 3D effect by Lay Mapping of diverse fabrics. The method of research is to weave the eight fabrics composed of cotton, linen, worsted, slender yarn, loop, $m{\acute{e}}lange$, woolen, and yarn twist with Hi-Tex program, and to practice 3D mapping with Hi-Print program. As a mapping object, the flared skirt which is a basic costume item is selected. As a result, the thickness of yarn in CAD system was fixed by the width of cross section rather than Count, especially by the width of core section not including the fluff section. The type of yarn such as cotton yarn, linen yarn, and worsted had effect on the shape of texture, but had few interrelations with dimension. In the case of 3D mapping, the textural characteristic and the dimension were presented precisely, whereas there were several limitations. First, the thickness of tissue has not been represented. Secondly, the effect of texture such as fuzzy look, loop was not expressed on the skirt outline including sideline and hemline. Thirdly, the difference of silhouette was not distinct. The common point in 2D and 3D operations is that the representation of texture is relatively accurate and that is difficult to measure and manifest of thickness, the side. For more professional digitalizing in fashion industry, above all in the domain of 3D, it must be supplement the subdivided and differentiated mapping process according to the texture, deviating from the existing analog-based organization which has to designate the form and silhouette suitable for tissue.

• 한국염색가공학회지
• /
• 제22권4호
• /
• pp.373-379
• /
• 2010

The laboratory inspection and analysis of several types of ropes such as edge tensile test, D/d tensile test and abrasion test were carried out in order to investigate the abrasion degradation by external damage and to obtain the fundamental data for measurement against the abrasion. PET ropes were socketed and evaluated under tensile testing. A yarn-on-yarn abrasion test machine has been developed to study the damage and failure associated with rubbing between fiber surfaces. The abrasion test method consists of sliding a length of interwrapped yarn against itself in a reciprocating fashion, either dry or immersed in liquid. It has also been adapted to measure yarn-on-yarn friction. The influence of spin finish on yarn friction and abrasion was investigated extensively. This study indicates that finish has a major effect not only on yarn performance but also on rope performance under the marine environment.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
• /
• pp.395-397
• /
• 2006

Air interlacing serves to protect the yarn against damage, strengthens inter-filament compactness or cohesion, and ensures fabric consistency. The air interlacing nozzle is used to introduce intermittent nips to a filament yarn so as to improve its performance in textile processing. The effect of various interlacing nozzle geometries on the interlacing process was studied. The geometries of interlacing nozzles with single or multiple air inlets located across the width of yarn channels are investigated. The basis case is the yarn channel, with a perpendicular main air inlet in the middle. Other cases have main air inlets, slightly inclined double sub air inlets, The yarn channel cross sectional shapes are either semicircular or rectangular shapes. The compressed impinging jet from the main air inlet hole hits the opposing bottom wall of the yarn channel, is divided into two branches, joins with the compressed air coming out from sub air inlet at the bottom and creates two free jets at both ends of the yarn channel. The compressed air movement in the cross-section consists of two opposing directional vortices. The CFD-FASTRAN flow parallel solver was used to perform steady simulations of impinging jet flow inside of the interlace nozzles. The vortical structure and the flow pattern such as pressure contour, particle traces, velocity vector plots inside of interlace nozzle geometry are discussed in this pater.

• 한국염색가공학회지
• /
• 제18권3호
• /
• pp.49-58
• /
• 2006

The purpose of this study was to examine the effect of covering yarn's twist on mechanical properties of knitted fabrics of composite yarns with single covering process. Four yarns that were used in this study: two different composite yarns made from the four kinds of cotton and functional polyester-(Poly-A) with the ratio of 52:48, and the rest two yarns are the original cotton 100% yarn and the poly-A 100% yarn. The two kinds of composite yarns, CP1 and CP2, were processed on the single covering process. CP1 was applied on the single covering process with S-800 tpm, where Poly-A was used as covering yarn and cotton was used as core yarn. CP2 was applied on the same process as CP1 except that Poly-A had been applied on the two-for-one twisting process with S-400 tpm on the previous step. Sixteen mechanical properties of all the four knifed fabrics knitted under the same knitting conditions were measured by KES-FB system with the outer knit condition. And 3D CAD dressmaking simulations, which were driven by some of the mechanical properties, were presented. The results were as follows: CP2 had high RT values with twisting of covering yarn. CP2 also had high B, 2HB values because of higher linear density. SMD was affected rather by twisting of covering yarn than by fine hair of the cotton surface. Twisting of covering yarn made it decreasing T value and increasing W value. Dressmaking 3D CAD simulations showed that there are buckling effects on CP2 because of high bending rigidity and shear rigidity.

• 한국의류산업학회지
• /
• 제5권3호
• /
• pp.267-272
• /
• 2003

Tactel(Nylon66) union fabrics were woven with the specification of 70d/34f nylon as warp for sport wear jacket. Weft yarn has three types; 100% cotton yarn, nylon core-spun yarn and nylon-polyurethane covering yarn as weft. Fabric structers were plain, twill and satin weave structure with the air jet loom. The mechanical properties of 8 fabrics were measured with KES-F and primary Hand Values and Total Hand Values were calculated. The results of the study were as follows: 1) There was little difference among LTs of N/CM fabric groups. RT of the fabrics with CM100's was bigger than that of fabrics with CM80's, resulting that the fabrics with CM100's have better formability. In terms of weaving structure, twill fabrics have shape deformation. 2) In comparison of RTs with weft yarn type, RT of N-PU covering yarn was the highest, followed by Nylon core-spun yarn and cotton yarn. Thus, the fabric with N-PU covering yarn has better stability of shape deformation. 3) Stretch yarn could express an excellent silhouette formation and twill and satin structures were better structure to make curvature on human form. 4) 2HG/G value of nylon core-spun fabrics was larger than that of N/C fabrics, but the silhouette formation of N/C fabrics was excellent. 5) The RC of N/PU was the highest, followed by N/P, and N/CM. 6) Koski of N/PU fabrics was the highest, Numeri of N/PU and N/Co-I were relatively higher than the others. THVs of N/CM-IV and N/CO-II were lower than the others, resulting that, twill structure was better than plain structure for a sport wear uses.

• 한국염색가공학회지
• /
• 제12권2호
• /
• pp.89-95
• /
• 2000

Effect of twist-setting time, temperature and cylinder layer for the physical properties of the twist yarn were investigated by separated 9 layer from yarn cylinder. Obtained results were as follow. Shrinkage of the yarn in middle layer shows high value with heat-permeation and in inner's shows low value because of cylinder hardness. And then yarn thermal shrinkage in outer layers shows more or less high value because twist yarn in the outer layer sets more faster. Concerning to the difference on the yam physical properties among cylinder layers, the changes on physical properties shows significant differences from the 7th layer to the last one. Linear density, T.P.M and initial modulus decreases but snarl index increases.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2003년도 추계학술발표대회 논문집
• /
• pp.95-98
• /
• 2003

In woven or knitted preforms for composites, the yams are often twisted for avoiding damage due to the contact with the textile machine elements. When the preforms of twisted yams are used in carbon/carbon composites, the thermal conductivity of the composites varies depending upon the degree of the yarn twist. This paper presents a thermal conductivity model of spun yarn composites. The thermal-electrical analogy and the averaging technique have been adopted in this analysis. The model prediction has been correlated with experimental results in order to confirm the model predictability. Parametric study has also been conducted to examine the effect of the yam twist on the thermal conductivity of spun yarn composites.