Conference Papers (KET)
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Item Estimation of Remaining Useful Life and Failure Probability of an Electrical Machine-Case Study(IEEE, 2023) Leffler, Jan; Trnka, Pavel
Item Bayesian Experiment Design for the Development of an Epoxy Resin Degradation Model(IEEE, 2023) Leffler, Jan; Kaska, Jan; Trnka, Pavel; Šmídl, VáclavItem The Behavior of Cold-Curing Resin after Thermal and UV Radiation Exposures(American Institute of Physics Inc., 2023) Hornak, Jaroslav; Trnka, Pavel; Prosr, Pavel; Michal, Ondřej; Kopřiva, Jiří
Item Influence of Prolonged Mixing of Silicon Dioxide Nanoparticles on the Electrical Properties of Resin Nanocomposites(American Institute of Physics Inc., 2023) Michal, Ondřej; Mentlík, Václav; Hornak, JaroslavItem New Approach In Designing Hexagonal-Shaped Antenna Based On Area Analysis(IEEE, 2022) Siahkamari, Hesam; Jahanbakhshi, Maryam; Lotfi, SaeedehItem Characterisation of Polyurethane Potting Compounds with Semiconductive Coating for Explosive Atmosphere Applications(IEEE, 2022) Kalaš, David; Kadlec, Petr; Pretl, Silvan; Soukup, Radek; Polanský, RadekItem The Effect of Various Flame Retardants on Thermal Properties of Cable Insulation(IEEE, 2022) Prosr, Pavel; Polanský, Radek; Chudoba, V.; Leńczyk, LukášItem Electrical Strength Tests of a Self-healable Copolymer Based on Ethylene and Anisylpropylene(IEEE, 2022) Nikolić, Valentino; Kadlec, Petr; Polanský, Radek; Nishiura, Masayoshi; Hou, ZhaominItem Real-Life Functional Tests of Conductive Joints of SMD Components on E-Textiles(IEEE, 2022) Hirman, Martin; Hamerník, Karel; Kalaš, David; Navrátil, Jiří; Moravcová, Daniela; Steiner, FrantišekItem Behaviour of printed resistors compatible with thick film copper technology(IEEE, 2022) Hlína, Jiří; Řeboun, Jan; Hamáček, AlešItem New Approach In Designing Hexagonal-Shaped Antenna Based On Area Analysis(Fakulta elektrotechnická ZČU, 2022) Siahkamari, Hesam; Jahanbakhshi, Maryam; Lotfi, Saeedeh; Pinker, JiříItem Textile Sensor for Skin Hydration Measurement(IEEE, 2022) Balabán, Jan; Blecha, TomášThis paper deals with the design and realization of capacitive textile sensors for skin hydration measurement. Skin hydration level is an important parameter for the healthy condition of the body and is also often used in dermatology and cosmetology. Many commercial devices are known for measuring skin hydration, which is mainly determined by medical doctors but is not suitable for longterm patient monitoring. For this reason, textile sensors and wearable evaluation electronic units were designed and created. The result is a wearable system including a textile sensor that can be easily integrated into clothes for better patient comfort. Skin hydration level is calculated based on measured sensor capacity. Obtained results will be useful for the following research on in-home care and smart textile.Item Higher Temperature Washing of Electrically Connected SMD Components onto the Textile Ribbons(IEEE, 2022) Hirman, Martin; Navrátil, Jiří; Steiner, František; Hamáček, AlešThis article addresses the higher temperature washing reliability research of interconnection technique for mounting SMD (surface mounted device) components onto conductive stretchable textile ribbons. It can be concluded that both tested interconnection technologies (i.e. low-temperature soldering and adhesive bonding) have some pros and cons, and both technologies are usable for dedicated applications. The results for soldered samples are better and stable for both tested washing temperatures 60°C and 92°C and are suitable especially for power supply applications or heating. The adhesive bonded joints have acceptable results only for 60°C washing temperature and are suitable for sensors, illumination, data transfer applications, or components with multiple leads. The research also shows that prepared joints have higher endurance than the whole ribbon.Item Analysis and Sintering Optimization of Nanoparticle Paste with High Silver Content(IEEE, 2022) Michal, David; Janda, Martin; Řeboun, JanThis paper deals with analysis, testing, and process optimization of new nanoparticle silvering paste with high silver content. Specifically, on ceramic substrates with printed conductive patterns created by thick film technology. Sintering is currently one of the most anticipated ways of connecting dies on substrates in power electronics field. Using ceramic substrates in combination with printed patterns brings out new challenges because of porous structure and ceramic specific attributes, especially when using presureless sintering as in this case. Presented paper is focused on analysis and comparison of structure and behaviour of the new nanoparticle paste with commercially available silver sintering pastes. Following step was initial testing with different deposition techniques and development of optimal sintering profile. After sintering examinations were also carried out. Shear test showing mechanical resilience, x-ray scanning for analysis of internal structure and stereoscopic analysis of sintered paste. Prolonging the temperature peak from 45 to 60 minutes and rising its temperature to 280°C shows better results in created joint. Higher shear strength was achieved together with more homogenous sintered structure. Lower porosity and presence of nanoparticles shows great potential for more homogenous, stable, and more resistive connection to mechanical separation.Item Method of Connecting Printed and Embroidered Conductive Paths in Smart Textiles(IEEE, 2022) Janda, Martin; Rostás, Kateřina; Pretl, Silvan; Řeboun, JanThis paper proposes a method of connecting conductive paths realized by embroidering and printing in smart textiles. The embroidering of conductive threads offers great electrical conductivity and the level of integration while technologies of printed electronics offer the realization of fine details. Connection is realized by overstitch of the printed contact pad. The durability of the connection is further improved with overprinting with conductive paste and encapsulation by lamination. Contact resistance and its change during the cyclic mechanical stress test and thermal shock test is measured. The proposed connection shows reliability during the thermal shock test as contact resistance is not affected. Also, during the cyclic mechanical stress test, the reliability and durability are observed.Item Embroidered Flexible Elastic Textile Antenna as Strain Sensor(IEEE, 2022) Radouchová, Michaela; Suchý, Stanislav; Blecha, TomášThis paper is focused on the design and testing of embroidered flexible elastic textile antennas for strain sensing based on the evaluation of changes in their electrical parameters. Samples of planar textile antennas for strain sensing were prepared by embroidered technology on elastic fabric. Antennas were of different shapes as split-ring resonators in 2 widths, bow tie, dipole, and as embroidery styles were chosen outline, meander, crossing. Conductive patterns were embroidered with hybrid threads containing polyester fibers and silver-coated copper wires. The stretching of the embroidered antennas was performed in one direction with a step of 10 mm on the stretching jig to their possible maximum. Results show that the resonant frequency decreases with increasing elongation for some antenna samples; it depends on the shape and embroidery style of the designed samples. Contour embroidery style shows a much better dependence on stretching in comparison with the crossing style.Item Examination of Wet Assembling Methods in Printed Flexible Electronics(IEEE, 2022) Janda, Martin; Pretl, Silvan; Michal, David; Řeboun, JanThis paper examines two methods of assembling electronics SMD components on flexible substrates with low-temperature resistance. As a contact medium for interconnection between component and conductive pattern, conductive adhesive MG Chemicals 8331S-15G or conductive Ag printing paste DuPont PE 874 was used. The contact resistance of samples was measured after the assembling process and then mechanical tests were performed. Samples were subjected to a bend test and a rapid change of temperature in the shock chamber. Tests have shown that Ag paste can withstand high mechanical and temperature stress due to its stretchability and can partly return to its previous state after mechanical stress is released. On the other hand, conductive adhesive, which is rigid, tends to fail under high mechanical and temperature stress. Ag paste shows great assumptions to be used in the field of flexible or even stretchable electronics as a contact medium.Item Influence of PCB Surface Finishes on Intermetallic Compound Growth(IEEE, 2022) Rous, Pavel; Pavlozas, Antonios Dionysios; Steiner, FrantišekThis article presents research focused on the intermetallic compound growing under different conditions. The quality of solder joints depends on many factors, one of which is the thickness of the intermetallic layer and its composition. Combination of multiple reflow processes which is common during the production process and thermal aging you can simulate long-term use of the product, which makes it possible to determine the condition of solder joints in the future. The growth of intermetallic layers using thermal aging is known, but the demand for lead-free solder causes new alloys with unknown properties. Each element in the solder alloy has a different impact on the resulting solder properties. The formation of intermetallic layers also depends on the surface finishes of the pads, so the object of the experiment is to compare the effect of known and used SAC305 solder with solder doped by Ge or Co at the various finishes of pads.Item Ultrasonic Welded Textile Thermocouples(IEEE, 2022) Kalčík, Jan; Soukup, RadekThis article deals with the problems of fabrication and testing of textile thermocouples. Thermocouples were made by ultrasonic welding of hybrid conductive constantan and copper threads. The embroidered thermocouple samples were realized by a 3-point crossing of threads and a 9-point crossing of threads. The hot thermocouple junctions were made using the ultrasonic welding method with added a TPU foil insert. The sensors were calibrated, and the results were discussed.
