Yazar "Yilmaz, Elif" seçeneğine göre listele

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    A Comparative Study of Cotton/PES Knitted Fabrics Produced from Recycled Fiber-Based and Virgin Yarns
    (Korean Fiber Soc, 2024) Yilmaz, Elif; Ozgen Keles, Banu
    This study deals with the effects of recycled fiber usage and repeated laundering on air permeability and bursting strength properties of knitted fabrics in three basic fabric structures. For this purpose, recycled and virgin cotton and polyester fibers were used in various combinations in fabric production. Fabrics were subjected to repeated laundering under different temperatures and varying washing cycles and were dried with two different drying methods. It has been determined that knitted fabrics produced from recycled cotton containing polyester yarns give similar results to fabrics produced from virgin fibers in terms of air permeability and bursting strength. It was suggested to use recycled cotton/virgin polyester yarns in the knitted fabric production to achieve fabrics with high air permeability and compatible bursting strength values. Moreover, artificial neural networks were used to predict the air permeability and bursting strength of produced fabrics before and after repeated laundering. The obtained regression values were over 99% for both properties. Finally, it can be said that artificial neural networks could be used to predict air permeability and bursting strength of recycled cotton and PES-based knitted fabrics successfully. The results of this research can help manufacturers to choose the effectual fiber content and knitted fabric construction to achieve the intended performance properties in fabrics made from recycled and virgin cotton and polyester blends.
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    ANALYSIS OF ADDED VALUE CREATION PROCESS IN READY-MADE CLOTHING SECTOR: "TURKISH CASE"
    (Ege Univ, 2016) Yilmaz, Elif; Atilgan, Turan
    Turkish ready-made clothing sector is the one of the leading sectors of the Turkish industry. The companies in this sector should produce high added value products to protect their power on the international competition and increase their market shares. Creation of added value depends on various factors like improving the performance in production, producing design products and creating a brand. To analyze the added value process, it is necessary to identify the activities which add value on final product. This study based on the data obtained from three different companies. One of them is in Istanbul, the others are in Izmir and all of them are active in ready-made clothing area. In addition, by considering added value creation process of the other companies in this sector, the added value ratio of each step of added value creation process and the factors which create the added value for the interviewed companies were determined. According to the study data, brand value is the most important factor which determines the added value and sales stage when the final product meets customers is the highest added value step can be said.
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    Development of 3D hollow woven fabrics with superior mechanical properties by using nitinol and steel wire core hybrid yarns
    (Sage Publications Inc) Yilmaz, Elif; Altas, Sevda
    In this study, nitinol and steel wire core hybrid yarns were produced from wires having two different diameters and used as warp yarns to weave 3D woven fabrics in two different fabric constructions. The steel bars with two different diameters were placed into the gaps between fabric layers to create a hollow form after fabric production. The fabrics produced with cold-worked nitinol wire were exposed to heat treatments at high temperatures to provide them shape memory property according to data obtained from DSC analysis. Conventional textile fibers are not durable to these temperatures; for this reason, carbon fiber was used both as sheath material of hybrid yarns and additionally as warp and weft carbon fiber yarns. All yarn and fabric tests were carried out simultaneously to evaluate the mechanical properties of nitinol and steel wire core hybrid yarns, and wire-reinforced fabrics. Tensile tests were applied to all wire and hybrid yarn samples, DSC and DMA analyses were conducted for only heat-treated nitinol wires. Low-velocity impact, tensile and pull-out tests were applied to fabric samples. Reference fabrics with no wire were produced and evaluated by comparing with wire-reinforced samples to provide a point of comparison to the data from the mechanical properties of wire-reinforced 3D fabrics. The study's results were analyzed with regression analysis using the backward method, and the parameters such as wire type, wire diameter, and fabric gap width for optimum fabric production were determined. Data obtained from all mechanical tests demonstrate that fabric samples with steel wire, thinner wire, and narrow gaps have better results than others. The effect of wire thickness was also found the same for the nitinol wire. DMA analyses show that the thinner nitinol wire is better than, the thicker one. Finally, an innovative technique has been developed in this study to weave carbon fiber on a conventional automatic sample loom without fiber breakage by twisting PVA yarn around the wire core hybrid and twisted carbon fiber yarns.
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    Development of 3D hollow woven fabrics with superior mechanical properties by using nitinol and steel wire core hybrid yarns
    (Sage Publications Inc, 2020) Yilmaz, Elif; Altas, Sevda
    In this study, nitinol and steel wire core hybrid yarns were produced from wires having two different diameters and used as warp yarns to weave 3D woven fabrics in two different fabric constructions. The steel bars with two different diameters were placed into the gaps between fabric layers to create a hollow form after fabric production. The fabrics produced with cold-worked nitinol wire were exposed to heat treatments at high temperatures to provide them shape memory property according to data obtained from DSC analysis. Conventional textile fibers are not durable to these temperatures; for this reason, carbon fiber was used both as sheath material of hybrid yarns and additionally as warp and weft carbon fiber yarns. All yarn and fabric tests were carried out simultaneously to evaluate the mechanical properties of nitinol and steel wire core hybrid yarns, and wire-reinforced fabrics. Tensile tests were applied to all wire and hybrid yarn samples, DSC and DMA analyses were conducted for only heat-treated nitinol wires. Low-velocity impact, tensile and pull-out tests were applied to fabric samples. Reference fabrics with no wire were produced and evaluated by comparing with wire-reinforced samples to provide a point of comparison to the data from the mechanical properties of wire-reinforced 3D fabrics. The study's results were analyzed with regression analysis using the backward method, and the parameters such as wire type, wire diameter, and fabric gap width for optimum fabric production were determined. Data obtained from all mechanical tests demonstrate that fabric samples with steel wire, thinner wire, and narrow gaps have better results than others. The effect of wire thickness was also found the same for the nitinol wire. DMA analyses show that the thinner nitinol wire is better than, the thicker one. Finally, an innovative technique has been developed in this study to weave carbon fiber on a conventional automatic sample loom without fiber breakage by twisting PVA yarn around the wire core hybrid and twisted carbon fiber yarns.
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    Effects of Recycled Fiber Usage and Laundering Processes on the Performance Properties of Knitted Fabrics
    (Korean Fiber Soc, 2023) Yilmaz, Elif; Keles, Banu Oezgen
    It is known that in recent years, major textile and apparel companies in the world have shown a great tendency towards recycled clothing within the scope of sustainability and it has been observed that recycled knitted clothes have started to take place in the product range of many big brands. However, the subject of recycled textiles is a topic that has become popular in recent years and the performance of recycled textiles in end use is not yet known. For this purpose, knitted fabrics were produced from Ne 20/1 open-end yarns with %50 recycled cotton/%50 recycled polyester, %50 recycled cotton/%50 virgin polyester and %50 virgin cotton/%50 virgin polyester yarns in this study. All fabrics were then subjected to laundering processes at two different washing temperatures and then dried in two separate ways for 5, 10, and 20 laundering cycles. These selected variables and recycled fiber contents were evaluated for their influence on fabric performance properties before and after predetermined laundering cycles. Comparative analyses supported with statistical analysis of circular bending rigidity, weight loss after laundering, and dimensional stability properties were carried out. Results demonstrated that interlock fabrics exhibit higher circular bending rigidity and dimensional change percentages than the other fabric types. Additionally, yarn type did not affect fabric stiffness. Dimensional changes in the wale direction were significantly affected by the yarn type and laundering cycle. Moreover, fabrics made of %50 recycled cotton-%50 recycled polyester yarn exhibited less weight loss percentages after repetitive laundering processes which proves their endurance that is comparable to commercial yarns and encourages us to use recycled yarns more commonly.
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    Improving the repetitive washing and abrasion resistance properties of fabrics produced with metallized yarns
    (Sage Publications Inc, 2020) Altas, Sevda; Yilmaz, Elif; Adman, Nildeniz
    Metallized yarns have become an integral part of fashion because they give extra sheen to garments and an inimitable appearance to fabrics, making them special yarns. However, because of repetitive washing and abrasions, the metallic part of the yarn in the fabric is removed and the fabric loses its brightness and becomes transparent. This study aims to solve this issue by searching for high-quality metallized yarn production methods to eliminate problems during usage. in the experimental part of the study, eight different types of metallized films were produced using the lamination technique with two kinds of adhesives. Non-laminated metallized polyester films were used as a reference to understand the effectiveness of the lamination process. Metallized yarns were produced from laminated metallized films by using standard production parameters. After producing nine different types of metallized yarns, monotype knitted fabrics were then from these yarns. Yarn's basic properties and fabric's mechanical properties were then measured to compare the effect of the thin film type, lamination process and adhesive type effect on these properties. the test results showed that the lamination technique significantly improves the resistance of the repetitive washing process and the abrasion property of fabrics. the best results were obtained with polypropylene thin films. However, they had a higher friction coefficient and a harder handle property than polyester films. When using a thinner polypropylene film, this problem could be eliminated, and the yarns could be an important alternative choice for commercially producing metallized yarns in the future.
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    Investigation of the cosmetic effects of pattern design and wearability in sports bras
    (Emerald Group Publishing Ltd, 2023) Yilmaz, Elif; Ondogan, Ziynet; Kilic, Arzu Sen
    PurposeThis study aims to develop a sports bra with cosmetic microcapsules that supports the breasts and provides an aesthetically upright and lifted posture by using 28 days period.Design/methodology/approachA fitting process was carried out on provided seamless sports bras to determine the criteria that have to be improved considering the desired properties. The new sports bras were produced after the pattern design was developed; cosmetic microcapsules were applied to some of the bras and some were used as a control group to compare the real cosmetic effects. Female subjects tried the newly developed sports bras in a 28-day wear trial. Measurements were taken at certain periods during the wear trials, and the obtained data were analyzed statistically.FindingsThe findings of this study determined that the product provides a decrease in breast girth and increases skin moisture and nipple height after 28 days of regular use due to the effect of cosmetic ingredients released from microcapsules. A great majority of subjects found the breast lifting and supporting property of the sports bra successful and were satisfied with the new shape of the subjects' breasts.Originality/valueFitting studies were carried out directly on the female body, and the designed and developed encapsulating type sports bra has been transformed into a cosmetic textile product that gains also cosmetic properties. The cosmetic effects of the bra were investigated with wear trials. On the other hand, the nipple height measure term was defined for the first time and added to the literature within the scope of the study.
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    Prediction of the Fabric's Crease Recovery Property with Taguchi Design of Experiment
    (Korean Fiber Soc, 2016) Altas, Sevda; Yilmaz, Elif
    The creasing characteristic of fabrics is affected by many factors like yarn twist, fabric density, fabric constructions, fabric thickness apart from the fiber type. In the first part of this study, the effect of yarn fineness, yam twist, fabric tightness and weave construction factors on crease recovery was studied. In the second part of the study, in order to improve the creasing recovery of the fabrics, shape memory alloy (SMA) wires were used and the effect of shape memory alloy (SMA) wire on the crease recovery of cotton fabrics produced with different types of weave constructions were determined. Due to the high cost of SMA wire and the weaving operation adversity the two experimental plans were designed according to Taguchi design of experiment (TDOE). From the analysis of the first part, it was found that the yam linear density had the greatest effect on fabric crease recovery compare to others. Twist coefficient was the second, weft density was third and the weave construction had the least significant effect on the crease recovery. The fabrics produced with coarser and low twisted yarns with high tightness and longer floats in the weave construction have higher crease recovery property. In the second part of the study, the application of the SMA wire significantly increased the crease recovery angle of the fabrics. The thickness of the SMA wire is very important and the effect depends on the wire thickness. The increase of the SMA wire thickness increases the crease recovery significantly. However it must be appropriate with the yarn and fabric properties. The distance between the SMA wire distances was expected to increase the crease recovery however the effect was found not significant. The fabrics produced with coarser yarns with longer floats in the weave construction have higher crease recovery property. However, statistically the effects of these parameters were found not significant due to the dominant effect of the wire thickness.
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    The prevalance of 22q11.2 deletion in children with congenital heart disease and dismorphic features
    (Springer, 2007) Kaya; Cankaya, Tufan; Yilmaz, Elif; Oztunc, Funda; Tuysuz, Beyhan