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YILDIZ, ZEHRA

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YILDIZ

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ZEHRA

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2012 - 2019112020 - 202414
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    Thermal Comfort of Woolen Fabrics Depending on Physical Properties
    (TAYLOR & FRANCIS INC, 2016) ATMACA, MUSTAFA; Dal, Vedat; Atmaca, Mustafa; Yildiz, Zehra; Ceviz, Nuray Oz; Hes, Lubos
    In this study, thermal comfort properties of woolen fabrics depending on the physical properties have been investigated. Thermal and water vapor resistance of fabrics have been measured by the PERMETEST instrument and air permeability has been investigated in a wind tunnel. The air permeability depends on the shape and value of the pores and inter thread channels, which are dependent on the structural parameters of the fabric. Theoretical model has been used in order to determine the porosity values. Experimental data and regression statistics proved that porosity and other fabric parameters have a very strong influence on thermal comfort property.
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    A novel thermal-based fabric defect detection technique
    (TAYLOR & FRANCIS LTD, 2015) BULDU, ALİ; Yildiz, Kazim; Buldu, Ali; Demetgul, Mustafa; Yildiz, Zehra
    During the fabric production process, many defects can be occurred stemming from the unevenness in spinning, weaving, finishing processes, or from the raw materials. The fabric quality control process for the detection of these defects is carried out by specialist operators. In this paper, a new method based on the use of thermal camera for detecting these defects from the textile fabric images is presented. For identification process of defective area, fabric images were obtained by a thermal camera during the fabric flow in quality control machine that was specially designed for this experiment. Defective and defect-free regions on fabric surface were determined by thermal camera due to the thermal differences. The mentioned thermal defect detection system will eliminate the worker usage for fabric quality control process, thus it will provide a cost-effective and competitive manufacturing.
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    PublicationOpen Access
    Usage of Cellulose Acetate Butyrate Based Oligomeric Structures on Cotton Fabric Coatings
    (2020-11-16) YILDIZ, ZEHRA; Yildiz, Zehra; Önen, Hacer Ayşen; Dehmen, Ozan Gazi; Güngör, Atilla
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    Ultrafine Carbon Fibers with Hollow-Porous Multilayered Structure for Supercapacitors
    (PERGAMON-ELSEVIER SCIENCE LTD, 2016) YILDIZ, ZEHRA; He, Tieshi; Su, Qunyan; Yildiz, Zehra; Cai, Kedi; Wang, Youjiang
    Electrospun fibers of mixed polyacrylonitrile/polyvinyl pyrrolidine (PAN/PVP) sheath and silicone oil core were obtained by coaxial electrospinning. PVP and silicone oil were then removed from the coaxial electrospun fibers via phase separation and carbonization processes, respectively, to make the hollowporous multilayered ultrafine carbon fibers. The relationship between the morphology and electrochemical performance of ultrafine carbon fibers was investigated. Results show that the supercapacitor based on electrode of hollow-porous multilayered ultrafine carbon fibers exhibits high conductivity, fast ion diffusion, high specific capacitance (231.6 F.g(-1)), high charging/discharging efficiency (99.7%), and low internal resistance (0.2 Omega) using tetraethylammonium tetrafluoroborate in acetonitrile as electrolyte. Additionally, this work also demonstrates a great potential in the preparation of carbon nano-materials with graphene-like multilayer structure. (C) 2016 Elsevier Ltd. All rights reserved.
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    Electrical properties and electromagnetic shielding effectiveness of polyester yarns with polypyrrole deposition
    (SAGE PUBLICATIONS LTD, 2012) USTA, İSMAİL; Yildiz, Z.; Usta, I.; Gungor, A.
    Polypyrrole was deposited on polyester yarns by vapour phase polymerization technique. Ferric chloride was used as an initiator. In order to determine the effect of the initiator concentration on polymerization process, four different initiator concentrations (0.2, 0.4, 0.6 and 0.8 mol/l) were used. The effect of the initiator in terms of tensile properties, electrical resistivities and morphological properties of the yarns was investigated. The polypyrrole deposited polyester yarns were then weaved in a handloom to form fabric for the investigation of surface resistivity and electromagnetic shielding effectiveness. Scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared analyses illustrated that polypyrrole has penetrated into the yarn structure and the highest polypyrrole deposition was obtained at the initiator concentration of 0.6 mol/l. Also, the highest electromagnetic shielding effectiveness value and the lowest surface resistivity were obtained at this concentration.
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    Preimpregnated natural fiber preforms
    (Elsevier Science, Oxford/Amsterdam , 2023-06-01) YILDIZ, ZEHRA; ERYILMAZ, OĞUZ; Yildiz Z., Eryilmaz O.
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    Preparation of flame retardant epoxyacrylate-based adhesive formulations for textile applications
    (TAYLOR & FRANCIS LTD, 2016) YILDIZ, ZEHRA; Yildiz, Zehra; Onen, Aysen; Gungor, Atilla
    In this research, UV-curable acrylated epoxy-based oligomer adhesive formulations containing vinylphosphonic acid (VPA) were prepared to adhere cord fabrics onto the rubber surfaces. In order to enhance the peel strength between cord and rubber, an alkali treatment was applied onto the cord fabrics prior to the adhesive application process. Adhesive formulations and alkali-treated cords were characterized by Fourier transform infrared (FTIR) spectroscopy. By changing the VPA ratio in adhesive formulation, peel strength, flame retardancy, and thermal properties were evaluated. Results proved that the 10% VPA-included adhesive formulation provided highest char yield values supporting the flame retardancy property and the highest peel strength value of 50.8N/cm between the cord fabric and rubber surfaces.
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    PublicationOpen Access
    Application of image processing for quantization and characterization of fabrics with polymeric coatings
    (PAMUKKALE UNIV, 2018) YILDIZ, KAZIM; Yildiz, Kazim; Yildiz, Zehra
    In this study, the dispersion quality of particles on polymeric coating formulations from cotton fabric surfaces was investigated by using gray level co-occurrence matrix and fractal dimension. Coating formulations with various nano particle inclusions were applied on cotton fabrics. The flame retardant property of coated fabrics were examined by thermal gravimetric analysis (TGA). Images from the coated fabric surfaces were obtained by using optical microscopy and then these images were used in gray level and fractal dimension feature extraction processes. The microscopic images of the coated fabrics in various particle amounts were analyzed by using the image processing technique, and then classification and quantization processes were performed. The results of the image processing were compared to the results of TGA. The sample containing 5% montmorillonite (MMT) was found as having the best coating quality level by using feature extraction method in image processing. The average classification performance among all the samples was found as 92.5%.
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    Effects of NCO/OH Ratio and Reactive Diluent Type on the Adhesion Strength of Polyurethane Methacrylates for Cord/Rubber Composites
    (TAYLOR & FRANCIS INC, 2018) YILDIZ, ZEHRA; Yildiz, Zehra; Onen, Hacer Aysen; Gungor, Atilla; Wang, Youjiang; Jacob, Karl
    A series of dual curable polyurethane methacrylate-based oligomers were synthesized by changing the NCO:OH ratio and then were included in adhesive formulations using trimethylolpropane trimethacrylate and tricyclodecane dimethanol diacrylate (TCDDA) as reactive diluents. The effects of NCO:OH ratio and reactive diluent type on the structural properties of UV-cured free films and adhesion properties between polyester cord/rubber surfaces were studied. The highest adhesion strength of the 103Ncm(-1) was obtained when the NCO:OH ratio was set as 4 and the TCDDA was used as a reactive diluent. [GRAPHICS] .