ANALYSING THE PHYSICAL AND MECHANICAL PROPERTIES OF CORE-SPUN YARNS

Core spun yarn is also named as complex, compound, composite or hybrid yarn can be defined as the combination of filament and staple fibres. A filament which is called core is covered by staple fibres called sheath. In this study, it was aimed to analyse physical and mechanical properties of ring core-spun and ring dual core-spun yarns. Moreover, conventional ring and OE-rotor yarns were used as reference materials for better assessment. For this purpose, unevenness and imperfections, hairiness, frictional properties and tensile properties of yarns were measured. It was observed that core and dual-core spun yarns have better unevenness and imperfections values than conventional ring and OE-rotor spun yarns. Also, friction coefficients of core and dual-core yarns for all surfaces (yarn, metal and ceramic) were found lower than the equivelant 100% cotton conventional ring and OE-rotor spun yarns. Results showed that ring yarns have the highest hairiness values and it was also found that there is no statistically significant difference between hairiness values of core-spun and dual-core yarns. When the breaking force and breaking elongation were examined, it was seen that dual-core yarns have the highest values whereas OE-rotor yarns have the lowest

Intermingling pressure level effect on micro polyester melange knitted fabric properties

369-375This study aims at investigating the effects of intermingling pressure level on properties of melange fabrics made of multifilament micro polyester yarns. For this purpose, unit weight, thickness, moisture management, transfer and surface properties of fabrics have been measured, and fabric porosity is analysed by image analysis methods. In addition, image analysis techniques are also used to determine the effect of intermingling pressure level on the visual properties of melange fabrics. Results show that the intermingling pressure level has statistically significant effects on the unit weight, fabric thickness, air permeability, fabric porosity and fabric’s visual properties

Comparing the packing densities of yarns spun by ring, compact and vortex spinning systems using image analysis method

This study is aimed at determining the packing densities of yarns produced by different spinning systems to investigate the fibre distributions for each system. For this purpose, 100% Tencel LF yarns with 19.69 tex linear densities are produced on ring, compact and vortex spinning systems. Cross-sections have been made by hard sectioning method using a rotary microtome. Packing densities of yarns are calculated by image analysis method. Results show that the compact yarns have the highest packing densities while vortex yarns have the lowest. However, differences between the packing densities of ring and compact yarns are not found statistically significant. In this study, density values of yarns (D, g/cm3) are also measured by Uster Tester 5 to evaluate the relationship between the packing density and yarn density values. Results show that the packing density values are parallel to yarn density values

Is vitamin D deficiency an independent risk factor for obesity and abdominal obesity in women?

Introduction: Vitamin D has been determined to have some effects on b cell function and insulin sensitivity, and it is known that type 2 diabetes mellitus and hyperparathyroidism can cause obesity. The aim of our study was to investigate if vitamin D deficiency without diabetes mellitus and metabolic syndrome is associated with obesity and abdominal obesity. Material and methods: The study included 276 healthy premenopausal women. To exclude other causes of obesity, postmenopausal women and subjects with diabetes mellitus and metabolic syndrome were excluded. Women were divided into two groups depending on their 25-hydroxyvitaminD3 [25(OH)D3] levels: subjects with vitamin D deficiency (Group 1) and subjects without vitamin D deficiency (Group 2). Body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) were compared between the two groups. Results: BMI, WC, WHR, rates of obesity, and abdominal obesity according to WC and WHR of Group 2 were lower than those of Group 1 (p = 0.0005, p = 0.0001, p = 0.0045, p = 0.032, p = 0.002, p = 0.011, respectively). 25(OH)D3 levels negatively correlated with BMIs (r = &#8211;0.480, p < 0.0001), WCs (r = &#8211;0.480, p < 0.0001) and WHRs (r = &#8211;0.312, p < 0.05). There were no differences between serum parathormone, calcium and phosphorus levels of Group 1 and 2 (p = 0.239, p = 0.354, p = 0.95, respectively). Conclusion: Vitamin D deficiency without diabetes mellitus and hyperparathyroidism may be associated with obesity and abdominal obesity.Wstęp: Wykazano, że witamina D wpływa na czynność komórek &beta; i wrażliwość na insulinę. Wiadomo również, że cukrzyca typu 2 i nadczynność przytarczyc mogą powodować otyłość. Celem badania było ustalenie, czy niedobór witaminy D u osób bez cukrzycy i zespołu metabolicznego wiąże się z otyłością i otyłością brzuszną. Materiał i metody: Do badania włączono 276 zdrowych kobiet przed menopauzą. W celu wyeliminowania innych przyczyn otyłości z badania wykluczono kobiety po menopauzie, chore na cukrzycę i osoby, u których rozpoznano zespół metaboliczny. Uczestniczki badania podzielono na 2 grupy w zależności od stężenia witaminy 25-hydroksyD3 [25(OH)D3]: grupa 1 &#8212; osoby z niedoborem witaminy D, grupa 2 &#8212; osoby z prawidłowym stężeniem witaminy D. Porównano wskaźniki masy ciała (BMI, body mass index), obwody talii (WC, waist circumference) i współczynniki talia/biodra (WHR, waist-to-hip ratio) w obu grupach. Wyniki: Wartości BMI, WC, WHR, odsetek osób otyłych i częstość otyłości brzusznej, określone na podstawie WC i WHR, były mniejsze w grupie 2, niż w grupie 1, (odpowiednio p = 0,0005; p = 0,0001; p = 0,0045; p = 0,032; p = 0,002; p = 0,011). Stężenia 25(OH)D3 były ujemnie skorelowane z wartościami BMI (r = &#8211;0,480; p < 0,0001); WC (r = &#8211;0,480; p < 0,0001) i WHR (r = &#8211;0,312; p < 0,05). Nie stwierdzono różnic między grupami pod względem stężeń parathormonu, wapnia i fosforu w surowicy (odpowiednio p = 0,239; p = 0,354; p = 0,95). Wnioski: Niedobór witaminy D u osób bez cukrzycy i nadczynności przytarczyc może się wiązać z otyłością i otyłością brzuszną

Intermingling pressure level effect on micro polyester melange knitted fabric properties

This study aims at investigating the effects of intermingling pressure level on properties of melange fabrics made of multifilament micro polyester yarns. For this purpose, unit weight, thickness, moisture management, transfer and surface properties of fabrics have been measured, and fabric porosity is analysed by image analysis methods. In addition, image analysis techniques are also used to determine the effect of intermingling pressure level on the visual properties of melange fabrics. Results show that the intermingling pressure level has statistically significant effects on the unit weight, fabric thickness, air permeability, fabric porosity and fabric’s visual properties

Comparing the packing densities of yarns spun by ring, compact and vortex spinning systems using image analysis method

351-357This study is aimed at determining the packing densities of yarns produced by different spinning systems to investigate the fibre distributions for each system. For this purpose, 100% Tencel LF yarns with 19.69 tex linear densities are produced on ring, compact and vortex spinning systems. Cross-sections have been made by hard sectioning method using a rotary microtome. Packing densities of yarns are calculated by image analysis method. Results show that the compact yarns have the highest packing densities while vortex yarns have the lowest. However, differences between the packing densities of ring and compact yarns are not found statistically significant. In this study, density values of yarns (D, g/cm3) are also measured by Uster Tester 5 to evaluate the relationship between the packing density and yarn density values. Results show that the packing density values are parallel to yarn density values. </span

Stochastic Modelling of Pilling Degree Changes During the Pilling Process of Wool Fabrics

As a fabric surface defect, pilling gives clothes an unpleasant appearance and is often characterized with small, complex clusters of fibers attaching to the surface of the garment caused by the fiber migration from yams to the fabric surface as the fabric rubs against itself, another fabric, or even the skin. In this study, a Markov chain model was built based on the pilling propensity of wool fabrics, evaluated with a scale ranging from 1 (severe pilling) to 5 (non-pilling). These degrees were defined as the state space of Markov chain. The numerical values of the transition probability matrix related to the pilling degrees were obtained by maximum likelihood estimation (MLE). Based on the matrix, it was intended to model the changes in the pilling process of woven wool fabrics. Furthermore, given that the fabric will eventually be in state 1, 2 or 3, accepted as unpleasant appearance; the conditional mean first passage times for any transient state to enter any recurrent state for the first time were determined

Extraction and Characterization of Natural Cellulosic Fiber from Taraxacum Sect. Ruderalia

The aim is to explore the utilization of cellulosic fibers extracted from the Taraxacum Sect. Ruderalia, which is also known as dandelion, introduces a potential reinforcement for the green composite industry. This research is focused on the analysis of chemical, physical, thermal, and morphological properties of the Taraxacum Sect. Ruderalia fibers. Its lightweight (1.397 g/cm(3)) with the presence of an acceptable cellulose ratio (52.7%) and high crystallinity (69.59%) provide comparable tensile strength (57.36 MPa) and Young's modulus (2.96 GPa) for Taraxacum Sect. Ruderalia fibers. The fibers are experimentally thermal resistant to 272 degrees C according to TGA that may be profitable in extrusion processes in polymeric composite manufacturing. The average fiber diameter and wall thickness were optically 233 mu m and 1.5 mu m, respectively. Taraxacum Sect. Ruderalia fibers have a rough surface character with some irregularities such as porosities, particles, indentations, protrusions, and also the microfibrillar structure which can support mechanical interlocking with polymer in a composite system. With all these encouraging properties, Taraxacum Sect. Ruderalia fibers can be good alternative reinforcement for common cellulosic bast fibers in the development of ecologically friendly and sustainable polymeric-based materials

Characterization of a novel natural cellulosic fiber extracted from the stem ofChrysanthemum morifolium

Natural fiber reinforced green composites have been attracting high attention nowadays, as the green movement in the world forced companies to use green materials instead of synthetic fibre reinforced composites. In this respect, the aim of the study is to investigate usage possibility of undervaluedChrysanthemum morifoliumstem fibers as a new reinforcement of composite materials. Chemical, thermal, crystallographic, density, mechanical and morphological characterizations of theC. morifoliumfibers were examined.Crystallinity Index, density and tensile strength values were found as 65.18%, 1.33 g/cm(3)and 65.12 MPa, respectively.Chrysanthemum morifoliumhas a low cellulose content of 32.9% while the thermal resistance temperature was determined as 267.5 degrees C. Although its cellulose content is low,C. morifoliumfiber can be a good alternative for many other reinforcement plant fibers in terms of tensile strength. The high tensile strength of the fiber can be attributed to the high crystallinity index and fiber morphology advantage (low lumen diameter and thick cell wall). Hollow fiber morphology can increase the insulation and absorption properties of the fibers and can also create a usage area in lightweight composites by providing low density. This study suggests a novel sustainable ecological reinforcement fiber for green polymer composites with low density, reasonable tensile strength, high surface hydrophobicity and high surface roughness