This study presents the effects of a novel plied yarn structure consisting of different yarn components and yarn twist levels on the Poisson's ratio and auxetic behavior of yarns. The plied yarn structures are formed with bulky and soft yarn components (helical plied yarn [HPY], braided yarn, and monofilament latex yarn) and stiff yarn components (such as high tenacity [HT] and polyvinyl chloride [PVC]-coated polyester yarns) to achieve auxetic behavior. Experimental results showed that as the level of yarn twist increased, the Poisson's ratios and the tensile modulus values of the plied yarns decreased, but the elongation values increased. A negative Poisson's ratio (NPR) was obtained in HT–latex and PVC–latex plied yarns with a low twist level. The plied yarns formed with braid–HPY and braid–braid components gave partial NPR under tension. A similar result was achieved for yarns with HT–latex and PVC–latex components. Since partial NPR was seen in novel plied yarns with braided and HPY components, it is concluded that yarns formed with bulky–bulky yarn components could give an auxetic performance under tension.

No abstract

Smoking Ban in Closed Public Spaces went into effect in Turkey on May 19, 2008. We aimed at investigating the status of smoking among hospital staff following the ban. The study was conducted with the staff of the university hospital other than physicians. A questionnaire form investigating the status of smoking among hospital staff, the effects of the ban on smoking in closed public spaces, their thoughts that might affect their decisions to quit smoking or to decrease the number of cigarettes smoked was implemented. Prior to each interview, the participants read and signed the informed consent form. Mean and percentage distributions were used in the evaluation of the data. Of 60 individuals, 68% were female, mean age was 40.72 ± 7.25. Of them 50% were active smokers. After the ban 55% of the smokers declared a decrease in the number of cigarettes they smoked, 37% said no change. The ban had no effect on smokers' decisions about quitting smoking. Social leadership and role model characteristics of healthcare professionals should be taken into consideration and the habit of smoking should be handled as a disease, and medical approaches including behavioral therapy should be given the necessary significance they deserve.

Bu çalışmada çekme kuvveti sebebiyle dokuma kumaşlarda gerçekleşen boyut değişikliklerinin ölçülmesi amacıyla dairesel Hough dönüşümü tabanlı bir görüntü işleme yöntemi geliştirilmiştir. Bunun için farklı yapısal parametrelere sahip dokuma kumaşlar üzerine iğneler yerleştirilerek, kumaşlar çözgü doğrultusunda çekme işlemine tabi tutulmuştur. Bu esnada 30 saniye süresince 5'er saniye aralıklarla alınan kumaş görüntüleri bilgisayara kaydedilmiştir. Kumaş görüntüleri üzerindeki iğneler arası mesafeler hem el ile çizim yöntemiyle hem de dairesel Hough dönüşümü tekniği kullanılarak geliştirilen görüntü işleme yöntemiyle ölçülmüştür. İki ölçüm yöntemi ile elde edilen sonuçlar incelendiğinde sonuçlar arasındaki sapmanın %1'den düşük olduğu görülmüştür. Tüm ölçümler hesaba katılarak hesaplanan ortalama yüzde sapma değeri ise yalnızca %0,26'dır. İki ölçüm yöntemi ile elde edilen sonuçlar arasındaki korelasyon katsayısı değeri 0,99 hesaplanmıştır. Geliştirilen görüntü işleme temelli ölçüm yöntemi, dokuma kumaşların gerilme altındaki boyut değişikliklerini kolay, hızlı ve doğru olarak ölçebilmektedir.

In this study, the auxetic performance and various physical properties of fabrics woven with braid yarn were examined. Fabrics were woven in plain weave with conventional warp and braid weft yarn. Experimental results showed that fabrics woven with braid weft yarn exhibited an auxetic behavior by giving Negative Poisson's Ratio (NPR) up to a certain elongation value under tension in the warp direction. In addition, it was observed that the NPR of fabric was affected by the thickness of the braid yarn and the tightness (compactness) of the fabric. It was found that the use of braid yarn in woven fabric improved various physical properties such as tensile strength, thermal resistivity and abrasion resistance. Use of braid yarns increased the tensile strength in the weft direction where braid yarns were used, increased thermal resistivity values at the fabric woven with thick and bulky braid yarns and also increased abrasion resistance.