Tomas Bata University in Zlín

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    9821 research outputs found

    Insight into the Li-storage property of surface-modified Ti2Nb10O29 anode material for high-rate application

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    Ti-based anode materials are considered to be an alternative to graphite anodes to accomplish high-rate application requirements. Ti2Nb10O29 (TNO15) has attracted much attention due to its high lithium storage capacity through the utilization of multiple redox couples and a suitable operating voltage window of 1.0 to 2.0 V vs Li/Li+. However, poor intrinsic electronic conductivity has limited the futuristic applicability of this material to the battery anode. In this work, we report the modification of TNO15 by introducing oxygen vacancies and using few-layered carbon and copper coatings on the surface to improve its Li+ storage property. With the support of the galvanostatic intermittent titration technique (GITT), we found that the diffusion coefficient of carbon/copper coated TNO15 is 2 orders of magnitude higher than that of the uncoated sample. Here, highly conductive copper metal on the surface of the carbon-coated oxygen-vacancy-incorporated TNO15 increases the overall electronic and ionic conductivity. The prepared TNO15-800-C-Cu-700 half-cell shows a significant rate capability of 92% when there is a 10-fold increase in the current density. In addition, the interconnected TNO15 nanoparticles create a porous microsphere structure, which enables better Li-ion transportation during charge/discharge process, and experiences an enhancement after the carbon and copper coating on the surface of the primary TNO15 nanocrystallites.CzechNanoLab Research Infrastructure; Ministry of Education, Youth, and Sports, Czech Republic; Technology Agency of the Czech Republic, TACR; HORIZON EUROPE Framework Programme, (101078935); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, (CZ.02.2.69/0.0/0.0/18_053/0017879, LM2023051, LTT20005, TH71020006)Ministerstvo ?kolstv?, Ml?de?e a Telov?chovy [LTT20005, CZ.02.2.69/0.0/0.0/18_053/0017879]; Ministry of Education, Youth, and Sports, Czech Republic (MEYS CR) [LM2023051]; CzechNanoLab Research Infrastructure (MEYS CR); Technology Agency of the Czech Republic [101078935]; Horizon Europ

    Discovering an orphan source of ionizing radiation with respect to occupational safety and health

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    Compliance with the principles of occupational safety and health is one of the preconditions for avoiding emergency events. Without a doubt, this is one of the underlying duties of every employer or operator of waste recycling centers. The risk to health resulting from an orphan source of ionizing radiation in the form of scrap metal is quite high and can affect a significant number of people. As part of the precautions relating to employees, the employer must analyze the risks associated with working with scrap metal and emphasize the possibility of any previous contamination. In practice, various methods and procedures are used to assess the risks at scrap metal collection facilities, which are mostly based on the knowledge and experience of their inspectors. However, this is not usually done by means of appropriate risk analysis methods, which is the main disadvantage. The goal of this article is to point at the risks related to discovering an orphan source of ionizing radiation by using the Ishikawa diagram and the point method. Furthermore, this article also deals with the demarcation of a safety zone with respect to the protection of health and the environment. The specification of risks, the proposal of recommended precautions, and the expeditious demarcation of a safety zone in the case of the intervention of fire brigades in order to protect and/or decontaminate the persons are also included.Technology Agency of the Czech Republic, TACR: VI04000080; Univerzita Tomáše Bati ve Zlíně: LQ =OtQ 59

    Structure and dynamics of the hyaluronan oligosaccharides and their solvation shell in water: organic mixed solvents

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    Hyaluronan (HA) is a natural polysaccharide occurring ubiquitously in the connective tissues of vertebrates widely used in the cosmetic and pharmaceutic industries. In numerous applications HA oligosaccharides are being chemically modified using reactions incompatible with aqueous solutions, often carried out in water: organic mixed solvents. We carry out molecular-dynamics (MD) simulations of HA oligosaccharides in water:1,4-dioxane and water:tert-butanol mixtures of different compositions. HA molecule causes a separation of the solvent components in its surroundings, especially in tert-butanol containing solutions, constituting thus a sol-vation shell enriched by water. Furthermore, interactions with ions are stronger than in pure water and depend on the solvent composition. Consequently, the dynamics of the HA chain varies with the solvent composition and causes observable conformational changes of the HA oligosaccharide. Composition of mixed solvents thus en-ables us to modify the interaction of HA with other molecules as well as its reactivity.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: 90140; Univerzita Tomáše Bati ve Zlíně: IGA/FT/2016/011, IGA/FT/2017/009, IGA/FT/2018/010, IGA/FT/2021/010, IGA/FT/2022/009Ministry of Education, Youth and Sports of the Czech Republic [IGA/FT/2016/011]; Ministry of Education, Youth and Sports of the Czech Republic through the e-INFRA CZ [e-INFRA CZ LM2018140]; Tomas Bata University in Zlin [IGA/FT/2017/009, IGA/FT/2018/010, IGA/FT/2021/010, IGA/FT/2022/009]; [90140

    Precision and dimensional stability of bonded joints of carbon-fibre-reinforced polymers parts

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    This article aims to investigate the accuracy and dimensional stability of bonded metal and CFRP (Carbon Fibre Reinforced Plastic) adherends. The motivation behind this study was to assess the suitability of CFRP for optical devices through the evaluation of precision bonding technology. A binocular was selected as a reference optical device. A technological sample was designed, with required total runout of key dimensions 0.05 mm. The sample underwent testing according to ISO 9022-1. The total runout was evaluated after production and environmental tests. Eight out of 15 samples were turned after gluing due to insufficient accuracy. None of the turned samples exceeded the total runout deviation of 0.01 mm, and the average value of the maximal deviation was 0.0041 mm. The noncalibrated samples performed significantly worse with the average value of the maximal deviation of 0.0164 mm. The measurements during the climatic tests showed that the largest deviation (on average 77.6% of the maximum achieved deviation) occurs at the first temperature loading. Subsequent temperature cycles caused lower deviations. The results highlight the significance of addressing deformations resulting from adhesive volume shrinkage-induced stress as a crucial factor in precision bonding technology. © 2023 by the authors.Ministry of Defence of Czech Republic; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMTMinistry of Education, Youth and Sports (MEYS, MSMT in Czech) [FV 22-10]; Project for the Development of the Organ-ization "VAROPS (DZRO VAROPS) Military autonomous and robotic assets" by the Ministry of Defence of Czech Republi

    Water policy and legislative responses to climate change in the Czech Republic

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    The recurring floods and droughts in the Czech Republic show that climate change requires far-reaching changes in water management. We analyse the responses already reflected in Czech water policy and legislation at three levels: strategic, statutory and constitutional. We first describe the substantial changes that have been satisfactorily introduced into the Czech government's policies. We then trace the far less successful developments in the law, which have so far essentially been limited to drought plans and restrictions on water extraction during droughts. At the core, we concentrate on the political attempts to constitutionalize water protection

    Regional dynamics of two European clusters: Cooperative financial tools and collective support as part of V4 presidencies' foreign approach towards WB6 partners

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    Based on current paradigmatic, programmatic and operational changes, which oversee how global systems were transformed through inter-actor dynamics and systemic rifts, we can underline the necessity for an in-depth comprehension of the political and economic interactions between regional actors, especially within CEE and the EUs' Neighbouring areas. Thus, as the present paper seeks to address this knowledge hiatus found in the field, there is an extrapolation and interpretation of the Visegrad Group's (V4) collaborative and cooperative patterns during the last full presidential cycle (Slovak Republic - 2018 to Slovak Republic - 2023). As such, this analysis is aimed at deciphering some of the ways used by the V4 to employ economic measures, as part of collective or individual foreign policy approaches, to further enhance Western Balkan partners' European trajectories and regional integratory processes, alongside their respective geostrategic and geoeconomic interests. When it comes to the methods utilised in this study, the primary and secondary questions are answered through an extensive collection, selection, and inspection of data produced throughout the V4 presidencies, including: official statements and papers (V4 (expert groups, op-eds, think-tank reports, etc.). Based on these procedures and forthcoming findings, we can highlight a noticeable increase in the constant economic flows both between the V4 - WB6 (Western Balkans 6) corridor per se and amongst their members, although collective efforts remain highly volatile due to variations in chairmanship. Moreover, the presidencies' core priorities towards the WB6 seem to follow the general continental pivot regarding the area, with several larger initiatives being spearheaded to optimise interconnectedness between both regions, especially in complementarity with other EU and economic contexts amongst V4 countries are historically close, it is possible to underline that their political environment allows for shared foreign policies to be created, particularly when it comes to enhancing well-founded neighbourhood relations, expanding towards other spheres of interest or assisting non-EU partners in their transition period (driven by their own development processes and good practices).Tomas Bata University in Zlin [RO/2022/07

    Impact of boundary control methods on bound-constrained optimization benchmarking

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    Despite initial indifference towards boundary control methods (BCM) in the context of metaheuristic algorithm design, benchmarking, and execution, our research demonstrates their critical importance. This study investigates how the choice of a particular BCM can profoundly influence the performance of competitive algorithms. We analyzed the top three algorithms from the 2017 and 2020 IEEE CEC competitions, posing the following question: Could a change in BCM usage alter an algorithm’s overall performance and, consequently, its ranking among competitors? Our findings reveal that paying attention to BCMs can lead to significant improvements. The experiments revealed that BCM selection can significantly impact an algorithm’s performance and, in some instances, its competition rank. However, most authors omitted to mention the implemented BCM, resulting in poor reproducibility and deviating from recommended benchmarking practices for metaheuristic algorithms. The conclusion is that the BCM should be considered another vital metaheuristics input variable for unambiguous reproducibility of results in benchmarking and for a better understanding of population dynamics. © 2023 Copyright held by the owner/author(s).Tomas Bata University in Zlin, TBU, (IGA/CebiaTech/2023/004

    Evolution of the polyphenolic content of Moravian white grape variety wines of different vintages during storage

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    Wine is known as a source of bioactive compounds and is one of the alcoholic beverages with the highest phenolic content. There has been growing interest in the composition of wine due to its beneficial properties for human health. This work focuses on biologically active and sensory attributes of white wine and presents research on wine chemical profiles in relation to their geographical origin, varieties and storage. The aim of this study was to investigate the phenolic compound evolution of 35 selected white wine varieties from the Moravian region in the Czech Republic. To separate and identify individual phenolic compounds in the wines, the high-performance liquid chromatographic method was used. A spectrophotometric method was applied for the determination of total polyphenol and total flavonoid content. This research presents results for the total benzoic and cinnamic acid derivatives, flavonols, flavanols and stilbene content of Moravian white grape varieties. Differences were found in the content of these compounds, and the results show that the phenolic concentrations depend on grape variety and storage time.Tomas Bata University in Zlin, TBU, (IGA/FT/2023/003)project of the Internal Grant Agency of Tomas Bata University in Zlin [IGA/FT/2023/003

    Mechanisms of cognitive trust development in artificial intelligence among front line employees: An empirical examination from a developing economy

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    Drawing upon insights from the trust literature, we conducted two empirical surveys with the front-line employees of firms in Pakistan investigating the factors influencing cognitive trust in artificial intelligence (AI). Study1 consisted of 46 in-depth interviews aimed at exploring factors influencing cognitive trust. Based on the findings of Study 1, we developed a framework to enhance employees’ cognitive trust in AI. We then conducted a quantitative survey (study 2) with 314 employees to validate the proposed model. The findings suggest that AI features positively influence the cognitive trust of employees, while work routine disruptions have negative impact on cognitive trust in AI. The effectiveness of data governance was also found to facilitate employees' trust in data governance and subsequently, employees' cognitive trust in AI. We contribute to the technology trust literature, especial in developing economics. We discuss the implications of our findings for both research and practice. © 2023 The Author

    Viscoelastic response of elastohydrodynamically lubricated compliant contacts below glass-transition temperature

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    The widespread use of polymers in the high-performance engineering applications brings challenges in the field of liquid lubrication in order to separate the rubbing surfaces by the coherent fluid-film thickness relative to not only the inelastic material response of the polymers. The determination of the mechanical properties by the nanoindentation and the dynamic mechanical analysis represents the key methodology to identify the viscoelastic behavior with respect to the intense frequency and temperature dependance exhibited by polymers. The fluid-film thickness was examined by the optical chromatic interferometry on the rotational tribometer in the ball-on-disc configuration. Based on the experiments performed, first, the complex modulus and the damping factor for the PMMA polymer describing the frequency and temperature dependence were obtained. Afterwards, the central as well as minimum fluid-film thickness were investigated. The results revealed the operation of the compliant circular contact in the transition region very close to the boundary between the Piezoviscous-elastic and Isoviscous-elastic modes of the elastohydrodynamic lubrication regime, and a significant deviation of the fluid-film thickness from the prediction models for both modes in dependence on the inlet temperature.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2022/003; Grantová Agentura České Republiky, GA ČR: 18-26849JCzech Science Foundation (GACR) [18-26849J]; Ministry of Education, Youth and Sports of the Czech Republic [557DKRVO (RP/CPS/2022/003)


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