The analysis of dimensional stability of 1x1 RIB Co and Co/LY knitwear

© 2018 Inst. Nat. Cercetare-Dezvoltare Text. Pielarie. All rights reserved. This paper analyzes the impact of knitwear's fiber composition, linear density and finishing of yarn used in the dimensional stability of the 1x1 RIB knitwear made on the same circular knitting machine. Dimensional stability of these samples was analysed by FAST 4 method. Different samples were compared across multiple indicators. The results show that the most stable dyed knitted fabric are made of cotton 96% and 4% of Lycra and of yarn with linear density 19.14 tex. Tightness factor's values in the dry relaxation stood at 17.90, in the wet 18.45, in total 18.73 and 18.59 in air conditioned terms. Knitwear with the highest values of dimensional instability are raw knitted fabric made of 100% CO, and yarn with linear density of 13.39 tex. Tightness factor's values in the dry relaxation stood at 12.16, in the wet 12.36, in total 13.26 and 13.35 in air conditioned terms

From collaboration to solutions: Encouraging collaborative problem solving through school practice

The aim of this paper is to present a viable, psychologically based framework designed for systematical promotion of the adolescents’ capacities for collaborative problem solving and possibilities for their cultivation through everyday school practice. Specifically, a model for designing teacher-training programs is proposed, wherein several elements of effective collaborative problem solving are drawn together.9th International scientific conference Technics and informatics in education – TIE 2022 16-18 September 2022Proceedings: [http://www.ftn.kg.ac.rs/konferencije/TIE2022/docs/Proceedings%20TIE2022.pdf

Speeding-up Scientific Knowledge Transfer and Improvement of Capabilities of emerging European National Metrology Institutes and Designated Institutes in the field of thermal measurements: Benefits and Impacts

Within the frame of a European project called Eura-Thermal, the general objective was to upgrade the regional metrological infrastructure (Bosnia & Herzegovina, Croatia, Ireland, Serbia...) with new capabilities, especially in the field of thermal measurements. This paper highlights the strategy used for improving in the short term, scientific knowledge transfer and the capabilities of different emerging institutes. Furthermore, as a main output, the impacts and benefit for Industry and for the end-users are also presented as examples. © 2018 Institute of Physics Publishing. All rights reserved.XXII World Congress of the International Measurement Confederation (IMEKO 2018

Dijagnostika i kontrola zdravstvenog stanja grla na jednoj farmi goveda

Zbornik radov

Predicting behavior of needled geotextile materials made of recycled polyester fibres up to yield point

158-163The paper reports the results of the analysis of mechanical properties of nonwoven geotextile material from recycled polyester fibres of areal density 150, 200, 250, 300 and 500 g/m2. Also, the limits to yield point of needled geotextile materials, which define the permissible loads of geotextiles, are determined. Using mechanical models (model of Lethersich) and experimental results, the behavior of needled geotextiles made of recycled polyester fibres in the region up to the yield point can be described. The proposed method and the results can be used to predict the acceptable loads that nonwoven geotextile materials made from recycled polyester fibres can be subjected to exploitation with application

Influence of relative density on deformation characteristics of plain weave fabrics

69-75The deformation characteristics of fabrics in relation to relative thread density have been studied. On the basis of experimental results and theoretical models, some real mathematical dependence has been set up, which can be used for projecting breakage characteristics of plain weave cotton fabrics. Equations for projecting breaking characteristics have been developed on the basis of fabrics geometrical model in linen weave and practical results. The equations include correction coefficients, depending on the relative density in fabrics. The results show that the relative thread density in fabrics affects their deformation characteristics. The relative thread density, if higher than 1 causes weaker quality parameters and this must be taken into consideration during designing of fabric

Influence of heater temperature and texturing speed on the physical-mechanical properties of polyamide textured yarns in false-twist texturing process

In this paper, the effect of technical and technological parameters in false twist texturing on physical-mechanical properties of polyamide yarns was studied. Partially oriented (POY) multifilament with fineness of 22f07x1 dtex was textured under factory conditions on a friction texturing ICBT model FT 15 E3 machine. Using low temperature long heaters the influence of heater temperature and texturing speed on crimping, shrinking and breaking characteristics of yarn was investigated. Thereby, the values for the ratio of surface speed of disks to linear yarn speed, (D/Y), of 1.9, and tension in texturing zone (stretching) of 1.305 and in winding zone of 0.954, were kept constant. The investigated texturing parameters affect the change of these characteristics to varying degrees. For heater temperatures of 200, 210 and 220 degrees C, linear negative correlation was found between the texturing speed, indicator of crimping and texturing speed and breaking characteristics, while the positive correlation was established between the speed of texturing and shrinkage. It was determined the correlation factor between the texturing process parameters and the analysed properties of the yarn. Based on the obtained results it can be concluded that with the established correlation between the speed of texturing and the investigated properties of the yarn, the correlation factor increases with the increase in heater temperature to 210 degrees C. However, at the temperature of 220 degrees C, generally in most cases this value decreases. Therefore, in this study, the optimum temperature of the heater is 210 degrees C, taking into account the selection of other parameter values of the D/Y ratio and stretching

The effect of false-twist texturing parameters on the structure and crimp properties of polyester yarn

In this paper, the effect of false-twist texturing parameters (texturing speed, heater temperature, draw ratio and disc-to-yarn speed ratio (D/Y ratio)) on the structure and crimp properties of polyester yarn has been studied using a high temperature heater and high texturing speeds. Textured yarn was analyzed and characterized in terms of the degree of crystallinity, degree of orientation and crimp properties (crimp contraction, crimp module and crimp stability). The most important parameters, significantly affecting yarn temperature and its uniformity and thus textured yarn structure and crimp properties, are texturing speed and heater temperature. Depending on these texturing parameters, the degree of crystallinity and orientation varied in the range of 24.48 to 36.66% and 0.371 to 0.595, respectively. The crimp characteristics increase with the increase in heater temperature, and decrease with the increase in texturing speed. The effect of draw ratio and D/Y ratio on the textured yarn structure and properties is less pronounced. Obtained results show that partially oriented polyester yarn used in this study can be textured at significantly higher texturing speed (up to 1100 m/min) than the standard texturing speed (up to 700 m/min) used for the yarn count examined

Dependence of Structural Characteristics of Polyamide Textured Yarns on the Parameters of the False Twist Yarn Texturing Process

In the false twist texturing process, due to the action of mechanical forces and heat, a disorientation of structural elements happens at all levels of the supramolecular structure. These changes are related to changes in the texturing parameters and mechanical properties of yarn. In this paper, investigated is the effect of technical-technological texturing parameters in the false twist texturing process on the structure of PA6.6 yarns. POY multifilament PA6.6 with a fineness of 22f07x1 dtex was used as experimental material. The yarn was textured on a friction texturing machine -ICBT model FT 15 E3. The exiting yarn speed (Vi) changed as 600, 700, 800 and 900 m/min; the heater temperature (T) was 200, 210 and 220 degrees C, and the ratio of the disk surface speed to the linear yarn speed (D/Y) was 1.9 and 2.1. The values of strain were kept constant at 1.305 (tension in texturing zone) and 0,954 in the winding zone. Analysed were the density, degree of crystallinity, degree of orientation, single filament diameter, the content of -NH2 and -COOH end groups, and the total content of end groups. From the results obtained it can be seen that the effect of the heater temperature is more significant than that of Vi and D/Y on the structural characteristics analysed. Analysing the experimental results it was found that linear positive correlations were established between the texturing speed and end (-NH2) groups, the texturing speed and end (-COOH) groups and the texturing speed and the total content of end groups. The correlation factor between the process parameters and yarn structural characteristics analysed is determined