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Conducting polypyrrole silicotungstate deposited on macroporous melamine sponge for electromagnetic interference shielding
Get PDFMacroporous melamine/formaldehyde sponge was coated in situ during the oxidation of pyrrole with iron(III) chloride hexahydrate in aqueous medium. The reaction mixture contained a heteropolyacid, silicotungstic acid, which protonated polypyrrole. Polypyrrole/silicotungstate deposits were prepared either in globular form or as nanotubes. The resulting hybrid composites thus combine an organic conducting polymer with inorganic component known, e.g., for its proton conductivity and electrocatalytic activity. The specific surface area of all materials was of the order of tens m2g−1. The molecular structure is discussed on the basis of FTIR and Raman spectra. The resistivity of the sponges was recorded as a function of compression to 10 MPa and it decreased from the order of 10 Ω cm to 0.1 Ω cm. The sponges were tested in electromagnetic interference shielding and absorbed over 80% of 9 GHz radiation frequency. The shielding is based mainly on the radiation absorption efficiency, −8.2 dB for globular polypyrrole and −13.1 dB for nanotubes, afforded by silicotungstic component. Hybrid composite sponges were subsequently carbonized at 650 °C in inert atmosphere when they converted to a sponge-like macroporous carbons enriched with nitrogen atoms. Their resistivity increased by two orders of magnitude after this process. The absorption of electromagnetic radiation, however, fell below 10%. Original and carbonized hybrid sponges may be of interest in the construction of macroporous electrodes.RP/CPS/2022/005; Technology Agency of the Czech Republic, TACR: TH71020006, TK03030157; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Grantová Agentura České Republiky, GA ČR: 22-25734SMinistry of Education, Youth and Sports of the Czech Republic (DKRVO) [TK03030157]; Technology Agency of the Czech Republic [22-25734S]; Czech Science Foundation; [DKRVO RP/CPS/2022/005]; [TH71020006
Connectedness among fan tokens and stocks of football clubs
Get PDFThis paper examines the dynamic connectedness among the fan tokens and their corresponding stocks using the TVP-VAR approach. We use daily data from December 11, 2020, to January 31, 2022, for the Juventus FC, AS Roma, Galatasaray, and Trabzonspor tokens and stocks. Our results indicate that shocks transmitted to any token are larger than the ones to the stocks, with the tokens being the net transmitters of shocks to both the tokens and stocks. Then, our results indicate that the two asset classes are considered independent of each other, with the total connectedness decreasing over time, and indicating that less than 10% of the contributions in any token (stock) is from the stocks (remaining stocks). This implies that the idiosyncratic contri-butions to the variations in the utilized group of assets are considerably low when compared to the system contributions. Finally, we provide some implications for investment and portfolio management
An effective data reduction model for machine emergency state detection from big data tree topology structures
Get PDFThis work presents an original model for detecting machine tool anomalies and emergency states through operation data processing. The paper is focused on an elastic hierarchical system for effective data reduction and classification, which encompasses several modules. Firstly, principal component analysis (PCA) is used to perform data reduction of many input signals from big data tree topology structures into two signals representing all of them. Then the technique for segmentation of operating machine data based on dynamic time distortion and hierarchical clustering is used to calculate signal accident characteristics using classifiers such as the maximum level change, a signal trend, the variance of residuals, and others. Data segmentation and analysis techniques enable effective and robust detection of operating machine tool anomalies and emergency states due to almost real-time data collection from strategically placed sensors and results collected from previous production cycles. The emergency state detection model described in this paper could be beneficial for improving the production process, increasing production efficiency by detecting and minimizing machine tool error conditions, as well as improving product quality and overall equipment productivity. The proposed model was tested on H-630 and H-50 machine tools in a real production environment of the Tajmac-ZPS company.Internal Grant Agency of Tomas Bata University [IGA/CebiaTech/2021/001
Silica nanoparticles from coir pith synthesized by acidic sol-gel method improve germination economics
Get PDFLignin is a natural biopolymer. A vibrant and rapid process in the synthesis of silica nanoparticles by consuming the lignin as a soft template was carefully studied. The extracted biopolymer from coir pith was employed as capping and stabilizing agents to fabricate the silica nanoparticles (n Si). The synthesized silica nanoparticles (n Si) were characterized by ultraviolet–visible (UV–Vis) spectrophotometry, X-ray diffraction analysis (XRD), Scanning Electron Microscope (SEM), Energy-Dispersive X-ray Analysis (EDAX), Dynamic Light Scattering (DLS) and Fourier-Transform Infrared Spectroscopy (FTIR). All the results obtained jointly and independently verified the formation of silica nanoparticles. In addition, EDAX analysis confirmed the high purity of then Si composed only of Si and O, with no other impurities. XRD spectroscopy showed the characteristic diffraction peaks forn Si and confirmed the formation of an amorphous nature. The average size ofn Si obtained is 18 nm. The surface charge and stability ofn Si were analyzed by using the dynamic light scattering (DLS) and thus revealed that then Si samples have a negative charge (−20.3 mV). In addition, the seed germination and the shoot and root formation on Vigna unguiculata were investigated by using then Si. The results revealed that the application ofn Si enhanced the germination in V. unguiculata. However, further research studies must be performed in order to determine the toxic effect of biogenicn Si before mass production and use of agricultural applications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.1/2018/187DST-FIST fund [SR/FST/LS-1/2018/187
Measuring business process innovations among tourism enterprises in the Czech Republic: A PLS-GLM approach
Get PDFThe Czech Republic has experienced momentous tourism expansion in recent years. Nevertheless, there is a lack of empirical investigation about this development. Innovations are an essential factor for the sustainable development of the tourism industry in the Czech Republic. The paper expounds on the effect of technical and process innovations among the tour and travel companies in the Czech Republic. The study surveyed 96 travel and tour operators aged 18-40 working in the various small, medium, and large travel agencies to determine their perceptions towards innovation in their respective travel businesses. A two-phased statistical process that combined PLS-SEM and GLM examined the responses of the individuals. It revealed that technical innovation had a robust and positive relationship with corporate profitability. Process innovation remains a grey area for Czech travel businesses. The study builds upon the Process Innovations in Colombia's Tourist Enterprises or PICTE framework to induct critical insights for travel agencies and tour operators to provide these businesses a way forward and make them more competitive and sustainable. It has been observed that tourism businesses that were not early adopters of disruptive technologies became vulnerable to market mechanisms. Therefore, the relevance of this study is further accentuated. COVID-19 has accelerated the climate of VUCA (volatility, uncertainty, complexity, and ambiguity) among Czech tour and travel operators, many of whom winded up or downsized operations. Many of these firms were in the medium and small segments. In light of the present situation, it becomes imperative that travel service providers invest in modern technologies and ensure the same diffusion among the staff. The paper gave the strategies towards human resource mapping and digital transformations for the best interest of the tourism industry. Future studies are recommended to focus on longitudinal measures towards understanding innovation propensities among small and medium-sized businesses. Mixed method studies are encouraged to comprehend the corporate dynamics of change management.TACR [TL01000191
Modeling the development of fire unconventional methodology
No full textThe article describes a proposal for a different approach to modeling the development of fire using multiagent systems and evaluating its benefits. One of the chapters lists the disadvantages that such an approach provides compared to currently used "conventional" models. Modeling and simulation is essential for understanding complex ecological systems. How-ever, knowledge of the structure and behavior of these systems is limited, and models must be revised frequently as our understanding of a system improves. Moreover, the dynamic, spatial distribution of activity in very large systems necessitates mapping natural mecha-nisms as logically as possible onto computer structures. Modeling and simulations are essential for understanding complex ecological systems. How-The knowledge structure and behavior of these systems is limited and models must be it will often be revised as our understanding of the system is prepared. In addition, the dynamic, spatial distribution of activity in very large systems involving the mapping of natural mechanic-logic into computer structures. This article describes the theoretical and algorithmic tools for creating component-based models and simulating dynamic bath phenomena. These methods focus on irregular distribution activity in ecological processes. This approach to event-based modeling naturally leads to efficient simulation algorithms. Ecological modeling benefits from these efficient simulation algorithms and the reuse of basic model components. The method is based on the event it is demonstrated on the physical model of fire propagation.Univerzita Tomáše Bati ve Zlíně: IGA/FAI/2021/002Internal Grant Agency of Tomas Bata University in Zlin [IGA/FAI/2021/002]; Department of Security Engineering, Faculty of Applied Informatic
Integration of the theory and practice in continuity with the development of key competencies—One of the necessary areas of solutions for the Czech university education
No full textThis is where the abstract should be placed. It should consist of one paragraph giving a co Human capital presents the most important asset of every society and particularly of education, which predetermines new possibilities for the social growth, it represents the principal social, ethical as well as political imperative. At the same time, the success within the competitive environment of the global market is subject to the high-quality workforce that is able to participate in the production of the top and innovative goods and services. A significant role belongs also to university education in continuity of the narrow link to the needs of the society and economy with the reflection in the strategic planning. The need to reach the still-persisting, ineffective interdependence of the “knowledge triangle”, i.e., the system of science and research, tertiary education and the area of innovations particularly with the economy area becomes one of the priority goals. The fundamental need thus lies in the orientation on quality and readiness of university graduates with the aim to increase their employability in the labor market, which is primarily based on required key competences of university graduates, i.e., acquiring the proper knowledge, skills, and abilities reflecting both the requirements of the educational subjects, as well as the requirements of employers in the necessary continuity of the integration of the theory and practice. The study presents the key data in the area of tertiary education with the focus on the specifications of the educational sector in the Czech Republic (in confrontation with the EU), with the possibilities for employability of university graduates in the labor market. © 2017, Springer International Publishing AG
Novelty search in particle swarm optimization
No full textThis paper presents a novel approach to implementing the Novelty search technique (introduced by Kenneth O. Stanley) into the Particle Swarm optimization algorithm (PSO). PSO is well-known for its impaired ability to operate in multidimensional spaces due to its inclination towards premature convergence and possible stagnation. This presented research aims to try various implementations of Novelty Search that could remove this inability and enhance the PSO algorithm. In total, we present five different modifications. The CEC 2020 single objective bound-constrained optimization benchmark testbed was used to evaluate the different Novelty Search-based modifications of the algorithm. All results were compared and tested for statistical significance against the original variant of PSO using the Friedman rank test. This work aims to increase understanding of implementing new approaches for population dynamics control, which are not driven purely by a gradient, and inspire other researchers working with different evolutionary computation methods
Review on anaerobic digestion models: Model classification & elaboration of process phenomena
Get PDFBiogas is a well-established renewable energy source produced from anaerobic digestion (AD) of biomass/ feedstock. It is probably the most versatile and efficient biofuel in terms of utilisable feedstocks and energy applications. To monitor, optimise, and control anaerobic digestion (AD), numerous mathematical models describing AD have been developed and reported. Although literature on the use of these models and their reviews have been published, their differences have not been collectively analysed and no generalised classification criteria for these models has been proposed based on such an analysis. This review covers most reported AD models, from the simplest linear equation capturing biogas production rate to complex Anaerobic Digestion Model No. 1. In addition to model classification and biochemical stages in AD, other processes like feedstock hydrolysis or mass and heat transfer essential to AD were discussed, analysed, and available models on them reviewed. This collective and comprehensive review approach has been undertaken to enable the evaluation of the interdependence of all processes, process factors, and process estimations and their individual, and interactive effects on AD.Norges Teknisk-Naturvitenskapelige Universitet, NTNU; Univerzita Tomáše Bati ve Zlíně: IGA/CebiaTech/2020/001, IGA/CebiaTech/2021/002Internal Grant Agency of the Tomas Bata University in Zlin, Czech Republic [IGA/CebiaTech/2020/001, IGA/CebiaTech/2021/002
Spontaneous brand awareness and consumer attitudes to brands in the Czech Republic and Slovakia
No full textThis article deals with the perception of domestic brands by consumers in the Czech Republic and Slovakia. It aims to present the results of research focused on the attitude towards domestic brands and their spontaneous awareness in the environment of the Czech Republic. These results are compared with a similar research conducted by the Faculty of Management, Comenius University in Bratislava, Slovakia. The survey sample in the Czech Republic was made up of 1028 respondents and 1022 in Slovakia. The issue of brand building is currently intensively addressed by the professional public as well as by companies. A successful brand is a strategic asset for any business. Considering this fact, this article also provides useful information on the real attitude of the consumer public towards domestic brands. © 2019, Springer Nature Switzerland AG