Materiały konferencyjne, referaty (WTMiWT)
Stały URI dla kolekcjihttp://hdl.handle.net/11652/159
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Pozycja Analysis of pressure parameters in orthopedic footwear for people suffering from diabetic foot syndrome(Wydawnictwo Politechniki Łódzkiej, 2022) Mikołajczyk, Zbigniew; Nowak, Iwona; Kuchyts, Yvan; Mikołajczyk-Solińska, MelaniaThe paper examines the anthropotechnical design of orthopedic footwear for patients with diabetic foot syndrome. A 3D distance knitted fabric is used for the shoe insert. For the purpose of the research, a 7 mm thick knitted fabric with transverse elasticity of 76 kPa was designed and produced on a doublebar warp knitting machine. With the use of the FreeMed Professional strain gauge mat, the pressures exerted by the foot on a „bare” walking surface and on the surface equipped with the distance knitted fabric were measured and compared, proving that in the latter case the unit pressure on the patient's foot decreased by 25%. The obtained measurements provide a good starting point for further research on the optimization of loads on the human foot, in case of various lower limbs diseases, including anatomical changes, as well as and in relation to people who are physically overloaded due to working in standing position or being in constant motion.Pozycja Spatial structure`s analysis of 3D knitted spacer fabric(Wydawnictwo Politechniki Łódzkiej, 2022) Walkowska, Aleksandra; Mikołajczyk, ZbigniewThe subject of this paper concerns an identification of a spatial structure of a warp-knitted spacer fabric, paying particular attention to the structure of the inner layer. The transverse elasticity of the knitted fabric, both in static and dynamic terms, will depend on the properties of the monofilament, its shape and Young's modulus. The environments of OptaView and Inventor programs were used in the research. Analytical activities were selected that enabled the creation of theoretical models. The empirical verification showed the compliance of the model objects with the actual shape of the threads. It has been proved that the developed methodology can be used in the description of the spatial structure of the spacer knitted fabric as an indispensable element in the numerical experiment of the mechanical properties of the knitted fabric.Pozycja Knitted shields against electromagnetic waves(Wydawnictwo Politechniki Łódzkiej, 2022) Mikołajczyk, Zbigniew; Nowak, Iwona; Szewczyk, Monika; Januszkiewicz, Łukasz; Junak, JoannaThe purpose of the research is to counteract the negative impact of electromagnetic waves on the human body by using knitted textile barriers. Four variants of knitted fabrics with plain weft stitches were designed and manufactured from electrically conductive yarns with resistance of 490 ohms. The variants of the knitted fabrics differed significantly in structural parameters, including loop density – varying from 15 to 0.9 thousand loops and fabric cover from 64 to 33%. The barrier properties against reflected waves at frequencies from 2 to 7 GHz ranged from 10 to 64 dB. It has been proven that shielding effectiveness SE depends on stitch geometry and structural parameters of the knitted fabric. It is a good starting point for further research on the optimization of the performance of knitted barriers against electromagnetic waves.Pozycja Numerical analysis of the dynamic thread stretching process(Wydawnictwo Politechniki Łódzkiej, 2022) Prążyńska, Aleksandra; Mikołajczyk, Zbigniew; Kuchar, MaciejThe subject of the paper is the analysis of the dynamic thread stretching process under extreme conditions of the excitation speed with the physical phenomena described in terms of rheological models. The analysis was carried out using three basic models relating to viscoelastic bodies, i.e. the Maxwell, Kelvin-Voigt and Standard 2 models. The relationships between the reaction forces of the stretched threads and the input parameters of the process were included both in an analytical form and in a numerical model. The theoretical analysis was related to the experimental tests carried out on polyester threads with a linear mass of 84, 110 and 334 dtex, assuming the tensile speed ranging from 0.6 to 1.5 m / s. The experiment was carried out on a custom designed test stand. In the conclusion of the obtained research, it can be stated that the most appropriate model for the description of the analysed thread stretching process is the Standard model 2 and it should be emphasized that the traditional analysis based on analytical relationships coincides with the results of numerical analysis. This proves the correctness of the adopted numerical model with specific boundary conditions.Pozycja Identification of wearing comfort of the textile uppers of commercial footwear(Wydawnictwo Politechniki Łódzkiej, 2022) Kaziur, Patrycja; Mikołajczyk, Zbigniew; Matusiak, MałgorzataKnitting technologies have contributed to the production of textile footwear not only to reduce waste, but also to increase their physiological comfort. In this study, the functional properties of twelve commercially available knitted uppers and two footwear leathers were identified. For each of the tested variants, the following parameters were determined: thickness, mass per square meter, air and water vapor permeability, and selected parameters related to the thermal insulation and moisture sorption. On the basis of conducted research, it was shown that the best parameters were characteristic for knitted fabrics with jacquard weaves produced on cylindrical crocheting machines of large diameters.Pozycja Design and research of a new type of anti-vibration gloves with the use of distance knitted fabrics(Wydawnictwo Politechniki Łódzkiej, 2022) Gębicki, Mateusz; Węglarski, Kamil; Pawliczak, Zbigniew; Frydrysiak, MichałThe paper presents tests of vibration damping in anti-vibration gloves with knitted spacers. The research was carried out at the Lodz University of Technology, Faculty of Materials Technology and Textile Design. Measurements of the anti-vibration properties of the gloves were made on two types of vibration generating devices - a hammer drill and an orbital sander. Two gloves with spacer knitted inserts with different physico-mechanical parameters and one standard available on the market were tested. The conducted research shows that all gloves have vibro-insulating properties to a different degree.Pozycja Preliminary studies on the preparation and properties of chitosan nonwovens modified with acid vapors(Wydawnictwo Politechniki Łódzkiej, 2022) Sikorski, Dominik; Bauer, Marta; Frączyk, Justyna; Draczyński, ZbigniewThe aim of the study was to develop methods for modifying chitosan nonwovens in the gas phase (application of acid vapors). Organic and inorganic acids were used in the research. The time of treating chitosan nonwovens with acid vapors ranged from 10 to 120 min. The conducted research has shown that it is possible to modify chitosan nonwovens with the use of acid vapors (organic and inorganic). It was found that the action of acid vapors does not have a destructive effect on chitosan fibers (SEM tests), which means that the developed method can be applied to various forms of chitosan materials, while the modification is carried out on the finished form. Microbiological tests were used to investigate the activity and growth of the microorganisms, which were related to the acids in the modified nonwovens. Only materials modified with acetic acid and hydrochloric acid were found to have bacteriostatic properties against S. aureus and E. coli (gramnegative and gram-positive bacteria). It was also found that chitosan formate significantly reduced the number of colonies of S. aureus.Pozycja Analysis of thermal aging effect on the tensile strength of textile materials intended for the reinforcement of conveyor belt(Wydawnictwo Politechniki Łódzkiej, 2022) Lemmi, Tsegaye Sh.; Barburski, MarcinWoven fabrics produced from high tenacity (HT) polyester/polyamide 66 yarns are most widely used to reinforce conveyor belts in the mechanical rubber goods industry. The tensile property of the conveyor belt is primarily dependent on the property of fabrics used to reinforce the belt. During the production process of the conveyor belt, the textile-rubber reinforcement undergoes a vulcanization process at high temperature to provide compulsory physio-mechanical properties of the belt by adhering the woven fabric with a rubber. Subjecting textile materials to high temperatures for the vulcanization process has an influence on the mechanical properties of the woven fabric. The main aim of this work was to investigate the effect of thermal aging on the tensile property of HT polyester yarn and woven fabric which is intended to reinforce conveyor belt. An extensive experiment on HT polyester yarn and the woven fabric was conducted by subjecting the textile materials to various aging temperatures. Additionally, the tensile property of fabrics after the vulcanization process of the conveyor belt was conducted to fully understand the effect of vulcanization temperature on the properties of woven fabric. The experimental test results of polyester yarn, woven fabric, and fabrics removed from the conveyor belt revealed that vulcanizing of the textile reinforced conveyor belt at high temperature(220 °C) can diminish the tensile strength and increase the elongation at break of the yarn and fabric.Pozycja Synthesis of mix chitin esters(Wydawnictwo Politechniki Łódzkiej, 2022) Bednarowicz, Anna; Tarzyńska, Nina; Patlewicz, Marta; Draczyński, ZbigniewThe aim of this study was the synthesis of chitin esters, which at a later stage could be used to produce antibacterial textiles. The esterification of chitin was carried out using butyric anhydride, succinic anhydride and methanesulfonic acid as a catalyst. The produced products were analysed by FTIR and NMR techniques and the dynamic apparent viscosity of the spinning solutions was examined. The products containing butyl and succinic anhydride in molar ratios 95/5 and 85/15 showed the best properties.Pozycja Accelerated hydrolysis of PLA fibers at low temperature(Wydawnictwo Politechniki Łódzkiej, 2022) Tarbuk, Anita; Čorak, Ivana; Đorđević, Dragan; Draczyński, ZbigniewThe polylactide (PLA) is the most common biodegradable material. However, its biodegradation requires hydrolysis of PLA to oligomers or monomers before microbes can act. Hydrolytic degradation of PLA depends on temperature, time and relative humidity. It takes months and years until complete biodegradation. If a catalyst is introduced, i.e. alkali or alcohol, it can be done in weeks. In this article, the alkaline hydrolysis was performed at low temperatures 40-60°C without and with the addition of cationic compound as an accelerator for the purpose of saving energy and time for complete PLA degradation. It has been shown that complete degradation can be achieved in only 10 min at 40°C.