Showing papers by "University of West Bohemia published in 2022"

Raman spectroscopy and DFT calculations of PEDOT:PSS in a dipolar field

Abstract: The conductive polymer-electrolyte interface plays an important role in many electrochemical devices. An unusual situation arises when a solvent-free ionic liquid (SF-IL) is used as the electrolyte because it behaves as a molten salt rather than an electrolyte solution. On the basis of Raman spectra, it was found that the presence of ion pairs of SF-IL in the vicinity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) results in a decrease in the oxidation level of the polymer and an increase in the HOMO-LUMO gap. The process of polymer "dedoping" and the modification of the electronic structure of the polymer are illustrated by quantum chemical calculations.

Metaverse and AI Digital Twinning of 42SiCr Steel Alloys

Abstract: Digital twins are the most important parts of Cyber-Physical Systems (CPSs), and play a crucial role in the realization of the Metaverse. Therefore, two important factors: flexibility and adaptability, need to be focused on digital twinning systems. From a virtual perspective, constructing buildings, structures, and mechanisms in the Metaverse requires digital materials and components. Hence, accurate and reliable digital models can guarantee the success of implementation, particularly when it comes to completing physical twins in the real world. Accordingly, four Machine Learning (ML) methods to make digital twins of an advanced 42SiCr alloy considering all of its uncertainties and non-linearities have been employed in this paper. These ML methods accelerate the digitalization of the proposed alloy and allow users to employ them for a wide range of similar metals. Based on this technique, producers can borrow these virtual materials and build their structures in the Metaverse. This way, if the properties of the materials were satisfactory, they might buy them and start manufacturing their products. As a case study, we focus on digital twining of an 42SiCr steel with some influential factors in its mechanical properties, making the nature of the alloy complex. Processes, including heat treatment, may restore the material’s deformability; however, Quenching and Partitioning (Q&P) not only eliminates the impact of cold forming but also provides advanced high-strength steel (AHSS) properties. In this research, the combined impacts of different Q&P treatments were investigated on the mechanical properties of 42SiCr steel alloy. The results have shown the acceptability and accuracy of the proposed ML methods in realizing the digital twins of this complex alloy.

Fabrication of flexible ternary polymer blends comprising polypyrrole, polyvinylalcohol, and poly(4‐styrenesulfonic acid): Study of structural, morphological, and dielectric properties

Abstract: A new ternary polymer blend was synthesized and characterized in the present work. A series of ternary polymer blends comprising water soluble polypyrrole, polyvinyl alcohol, and poly(4-styrenesulfonic acid) were prepared by solution casting method. The structural, electrical, and thermal properties of prepared ternary blends were investigated. X-ray diffraction studies indicated the semicrystalline nature of the polymer blends and chemically interacted polymer chain were revealed by Fourier transform infrared spectra. The morphological phase transformations were observed from scanning electron microscope and atomic force microscopy images. Thermogravimetric analysis explained the thermal degradation process. The ternary blends also possess excellent mechanical stability observed through force versus extension plot. The dielectric constant value of ternary blends was obtained in the range of 600–800 at low frequency range. The highest conductivity obtained was between 10−1 to 10−3 S cm−1 for ternary blends at higher frequency range. The overall results explains the charge transportation and relaxation process in the ternary blends due to presence of an electric field. The excellent dielectric constant values of ternary blends will be efficient for various electronics applications.

Influence of Sweat on Joint and Sensor Reliability of E-Textiles

Abstract: This article addresses reliability under the sweat of interconnection techniques for the mounting surface mounted device (SMD) components and fully printed humidity sensors onto conductive stretchable textile ribbons. Samples underwent testing for the effect of ageing by artificial sweat on their electrical resistance using both alkaline and acidic artificial sweat. The best results in terms of electrical resistance change were obtained for samples soldered to the conductive fibers interwoven in the ribbon. However, this method can damage the ribbon due to the high temperature during soldering and significantly reduce the mechanical properties and flexibility of the ribbon, which can lead to a limited service life of samples. On the other hand, adhesive bonding is a very interesting alternative, where the above-mentioned properties are preserved, but there is a significant effect of sweat ageing on electrical resistance. The results of fully printed graphene-based humidity sensors show that, for the intended use of these sensors (i.e., detection of changes in moisture on the human body), usage of the samples is possible, and the samples are sufficiently reliable in the case of sweat degradation. In addition, the response of the sensor to humidity is quite high: 98% at a relative humidity of 98%.

Statistical Study on Human Temperature Measurement by Infrared Thermography

Abstract: Increased temperature in humans is the symptom of many infectious diseases and it is thus an important diagnostic tool. Infrared temperature measurement methods have been developed and applied over long periods due to their advantage of non-contact and fast measurements. This study deals with a statistical evaluation of the possibilities and limitations of infrared/thermographic human temperature measurement. A short review of the use of infrared temperature measurement in medical applications is provided. Experiments and statistics-based evaluation to confirm the expected accuracy and limits of thermography-based human temperature measurement are introduced. The results presented in this study show that the standard deviation of the thermographic measurement of the eyes maximum temperature was 0.4–0.9 °C and the mean values differences from the armpit measurement were up to 0.5 °C, based on the used IR camera, even though near ideal measurement conditions and permanent blackbody correction were used. It was also shown that a certain number of outliers must be assumed in such measurements. Extended analyses including simulations of true negative/false positive, sensitivity/specificity and receiver operating characteristics (ROC) curves are presented. The statistical evaluation as well as the extended analyses show that maximum eyes temperature is more relevant than a forehead temperature examination.

Towards the Principles of Populist Communication? The Topic of Corruption in the Election Manifestos of Czech Political Parties

Abstract: The article examines how use of the topic of corruption in the election manifestos of Czech political parties has transformed over the course of the entire post-communist period. The theoretical framework used to grasp the anti-corruption positions expressed in the manifestos is populism. The study builds on the discussions about mainstream political actors (not) adopting populist principles and on the methodological debate around the possibilities offered by populist communication research. Using a content analysis and the principle of triplets, the article analyses the election manifestos of all the parties that were successful in the parliamentary elections between 1990 and 2017 in order to determine whether there was a stronger presence of populist principles in communication on the topic of corruption. Among other things, the study shows that: (1) statements on corruption that are consistent with a populist communication strategy can be found in parties that are not commonly understood as populist throughout the entire researched period; (2) mainstream parties did not respond to the success of populists in the 2010, 2013, and 2017 elections by adopting populist principles; (3) the populists who won a share of power strengthened the elements of populist communication in the next election manifesto.

On subhomogeneous indefinite p-Laplace equations in the supercritical spectral interval

Abstract: We study the existence, multiplicity, and certain qualitative properties of solutions to the zero Dirichlet problem for the equation $$-\Delta _p u = \lambda |u|^{p-2}u + a(x)|u|^{q-2}u$$ in a bounded domain $$\Omega \subset {\mathbb {R}}^N$$ , where $$10\}$$ , when the parameter $$\lambda $$ lies in a neighborhood of the critical value $$\lambda ^* := \inf \left\{ \int _\Omega | abla u|^p \, dx/\int _\Omega |u|^p \, dx: u\in W_0^{1,p}(\Omega ) {\setminus } \{0\},\ \int _\Omega a|u|^q\,dx \ge 0\,\right\} $$ . Among main results, we show that if $$p>2q$$ and either $$\int _\Omega a\varphi _p^q\,dx=0$$ or $$\int _\Omega a\varphi _p^q\,dx>0$$ is sufficiently small, then such solutions do exist in a right neighborhood of $$\lambda ^*$$ . Here $$\varphi _p$$ is the first eigenfunction of the Dirichlet p-Laplacian in $$\Omega $$ . This existence phenomenon is of a purely subhomogeneous and nonlinear nature, since either in the superhomogeneous case $$q>p$$ or in the sublinear case $$q2q$$ and $$\int _\Omega a\varphi _p^q\,dx>0$$ is sufficiently small, then there exist three nonzero nonnegative solutions in a left neighborhood of $$\lambda ^*$$ , two of which are strictly positive in $$\{x\in \Omega : a(x)>0\}$$ .

Methyl formate and dimethyl ether electro-oxidation on Pt Pd Sn catalyst supported on carbon nanotube decorated with carbon dots

Abstract: In this work, methyl formate (MF) and dimethyl ether (DME) electro-oxidation was studied on equimolar ratio PtPdSn catalyst supported on Vulcan Carbon XC-72, carbon nanotubes (CNT), and CNT–nitrogen-doped carbon dots (NCDs) composite. The ternary catalyst was synthesized by the ethylene glycol-assisted thermal reduction method and NCDs were synthesized by a hydrothermal method in the presence of CNT to form CNT-NCDs composite, in which the NCDs are incorporated onto the CNT surface. The activity of the catalyst in the oxidation of MF and DME was analyzed using cyclic voltammetry and chronoamperometry techniques. The ternary catalyst supported on CNT-NCDs composite (Pt1Pd1Sn1/CNT-NCDs) showed a peak oxidation current of 75 mA/mg and 365 mA/mg for DME and MF, respectively, highest among the studied Pt1Pd1Sn1/XC-72 and Pt1Pd1Sn1/CNT. The onset potential of DME on Pt1Pd1Sn1/CNT-NCDs catalyst shifted negatively by ∼200 mV compared to PtRu. Irrespective of the support material, the ternary catalysts showed a significant negative shift in the onset and peak potential of COad oxidation compared with commercial PtRu. The oxidation behavior of MF was studied in conjugation with its hydrolysis products methanol, formic acid, and mixed fuel (formic acid + methanol) solution, which disapproves the earlier proposed acid-catalyzed hydrolysis of MF to a significant degree during the electrochemical experiment. Hence, the CNT-NCDs supported ternary catalyst showed high catalytic activity and stability for electro-oxidation of DME and MF.

Clipping and Intersection Algorithms: Short Survey and References

Abstract: This contribution presents a brief survey of clipping and intersection algorithms in E2 and E3 with a nearly complete list of relevant references. Some algorithms use the projective extension of the Euclidean space and vector-vector operations, which supports GPU and SSE use.

Line Clipping in E3 with Expected Complexity O(1)

Abstract: A new line clipping algorithm against convex polyhedron in E3 with an expected complexity O(1) is presented. The suggested approach is based on two orthogonal projections to E2 co-ordinate system and on pre-processing of the given polyhedron. The pre-processing enables to speed up solution significantly. The proposed method is convenient for those applications when many lines are clipped against constant convex polyhedron. Theoretical considerations and experimental results are also presented.

Current Trends in Road Traffic Network Division for Distributed or Parallel Road Traffic Simulation

Abstract: Road traffic simulation is one of the useful tools, which can help to cope with steadily increasing intensity of road traffic. A distributed or parallel computing environment can significantly speedup the simulation execution, but the road traffic network division is usually required. There are many existing methods for road traffic network division based on various approaches. However, there is a lack of surveys mapping these methods. For this reason, this paper is a survey of existing methods for road traffic network division published in last two decades. It is not a systematic review, as it does not try to answer specific scientific questions. Its purpose is to map and categorize the existing methods for road traffic network division and to summarize their common features. Such a survey can be useful as a good starting point for the related work exploration for any teams or individuals dealing with road traffic network division and distributed or parallel road traffic simulation.

Hamilton‐connected {claw, bull}‐free graphs

Abstract: The generalized bull is the graph B i , j ${B}_{i,j}$ obtained by attaching endvertices of two disjoint paths of lengths i , j $i,j$ to two vertices of a triangle. We prove that every 3-connected { K 1 , 3 , X } $\{{K}_{1,3},X\}$ -free graph, where X ∈ { B 1 , 6 , B 2 , 5 , B 3 , 4 } $X\in \{{B}_{1,6},{B}_{2,5},{B}_{3,4}\}$ , is Hamilton-connected. The results are sharp and complete the characterization of forbidden induced bulls implying Hamilton-connectedness of a 3-connected {claw, bull}-free graph.

Towards automatic validation of composite heterogeneous systems in edge situations

Abstract: Systems implementing safety functions are becoming more complex, which is also related to their communication and perception capabilities in an environment. Such systems, primarily seen in mobility, become more susceptible to failures in complex decision-making situations that are difficult to uncover. This paper presents an idea formed in a PhD topic on validating and verifying the system specified by formal logic models. We aim to do so by using automatically generated test scenarios including edge situations (as generalizations of edge cases) invoked by an environment in a simulation tool.

Sellars on the Intersubjectivity of “We-Intentions”

Abstract: The notion of intersubjective “we-intentions” is central to Sellars's philosophical system, especially to his account of morality. However, what precisely makes these intentions intersubjective and why we need them often remains unclear in Sellars's texts. This chapter attempts to bring more clarity to these issues. Stefanie Dach argues that we can characterize the moral domain from a Sellarsian perspective as a domain of consonant practical reasoning with intentions. She shows that “I-intentions” cannot serve in such consonant practical reasoning because of two constraining features: their indexicality and their merely relative reasonableness. She then reconstructs how Sellars can address these two problems. Dach also suggests that there is a change in Sellars's ideas about the intersubjective aspects of we-intentions at the end of his career, where he seems to abandon his former “mode account.” Based on this reconstruction of Sellars's motivations for introducing intersubjective intentions, Dach argues that this change is a sensible one.