Cardiovascular diseases are the most frequent cause of death worldwide. Cases of cardiac arrest can often be attributed to undetected cardiac arrhythmia. Detecting rare episodes of arrhythmia necessitates long-term ECG measurements along days or weeks. However, due to the relatively small number of electrodes used for these ECGs, abnormal episodes can still go unrecognized. This article thus describes the development of underwear with ten inbuilt textile ECG electrodes, allowing for the measurement of long-term 12-lead ECG. As against the constructs of other research groups, the position of electrodes offers the same detection directions as the common 12-lead ECG equipment in hospitals or medical practices. Long-term tests have shown the suitability of the sensory underwear variants for men and women to detect reliable ECG signals without disturbing the patients’ comfort.
A number of PCB defects, though having passed successfully the defect identification procedure, can potentially grow into critical defects under the influence of various external and (or) internal influences. The complex nature of the development of defects leading to PCB failures demands developing and updating the data measuring systems not only for detection but also for the prediction of future development of PCB defects considering the external influences. To solve this problem, it is necessary to analyse the models of defect development, which will allow predicting the defect growth and working out the mathematical models for their studies.
The study uses the methods of system analysis, theory of mathematical and imitation modelling, analysis of technological systems. The article presents four models for determining the theoretical stress concentration factor for several types of common defects, considering the strength loss of PCB elements. For each model the evaluation of parameters determining its quality is also given. The formulas are given that link the geometry of defects and the stress concentration factor, corresponding to four types of defects. These formulas are necessary for determining the number of cycles and time to failure, fatigue strength coefficient.
The chosen models for determining the values of the stress concentration factor can be used as a database for identifying PCB defects. The proposed models are used for software implementation of the optical image inspection systems.
We explore the conductive mechanism of yarns made from metallic fibers and/or traditional textile fibers. It has been proposed for the first time, to our knowledge, that probe span length plays a great role in the conductivity of metallic fiber-based yarns, which is determined by the probability and number of conductive fibers appearing on a cross section and their connecting on two neighboring sections in a yarn’s longitudinal direction. The results demonstrate that yarn conductivity is negatively influenced to a large extent by its length when metallic fibers are blended with other nonconductive materials, which is beyond the scope of conductivity theory for metal conductors. In addition, wicking and wetting performances, which interfere with fiber distribution and conductive paths between fibers, have been shown to have a negative influence on the conductivity of metallic fiber-based yarns with various structures and composed of different fiber materials. Such dependence of the conductivity on the probe span length, as well as on the moisture from air and human body, should get attention during investigation of the conductivity of metallic fiber-based composites in use, especially in cases in which conductive yarns are fabricated into flexible circuit boards, antennas, textile electrodes, and sensors.
.5 dB). The value of SE for Ag sample is slightly higher compared with Au sample. The average values of shielding effectiveness over a frequency range of 2.5 GHz to 3.5 GHz for the samples are as follows: SE PANAg = 2.42 dB and SE PANAu = 2.27 dB. Fibers with Au and Ag nanoprecipitations lead to dispersion of electromagnetic radiation which results in the shielding properties. In future, the works will be directed to much higher concentrations of Au and Ag additives to achieve the percolation threshold of nanoprecipitations in order to form conductivepaths. Thanks
, and C3 in the electrical circuit of Figures 2 and 3 , it is clear that EC warp and weft yarns of a woven fabric can be used to do the transport of the electrical energy. Figure 2 A woven circuit electrically connecting a smart phone to the components C1, C2, and C3. Figure 3 The resulting electro-conductivepath. The hybrid fabric studied in this paper is composed of two EC yarns and conventional yarns making the base fabric. If a weft and warp EC yarn intersect perpendicular, they make contact, an EC contact. A small electric circuit can be created using only a
samples [ 1 ], as already has been confirmed from Raman studies. The delocalized π-electrons are formed in the carbonaceous clusters as a result of sp 3 -sp 2 rehybridization [ 41 ]. Thus, carbon clusters act as charge carriers/conductivepaths in the implanted samples. With the increase in ion fluence, the growth of carbon clusters is increased. Thus, charge carrier density is increased. In these conductive islands, the delocalized π-electrons move through hopping between the islands. This hopping current enhances the electrical conductivity of implanted samples [ 1
.24 Relatively small differences between the measured parameters can be observed. In each case the real part of the antenna impedance is higher than in the numerical model. The defects that appear on the printed elements are the main reason of the resistance increase. Both the cracks and the shape change of some conductivepaths lead to the substantial resistance increase. Moreover, some elements have locally printed defects connected with worsened wetting conditions of the substrate material. The increase of the resistance can be also observed in the self-resonance frequency