Tomas Bata University in Zlín
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Decorated cenosphere surface with bioreduced silver nanoparticles for environmental applications
Get PDFCenospheres (CF) are hollow spherical particles primarily composed of silica (SiO2) and alumina (Al2O3), known as aluminosilicate ceramic microspheres. In this study, CF were fractionated into the four size ranges (40–80 μm, 80–125 μm, 125–160 μm, 160–200 μm), purified, and activated using piranha solution (PS). Acid treatment activation was followed by the CF functionalization with biosynthesized silver colloidal nanoparticles (AgNPs). Silver integration was confirmed using elemental analysis (5.8–7.1 wt% of Ag), and electron microscopy revealed AgNPs (∼45 nm) unevenly distributed and locate at surface defects. X-ray diffraction (XRD) analysis confirmed the presence of quartz and mullite phases in both raw and modified CF, indicating structural stability during processing. Sound absorption tests revealed that while larger CF particles—especially the 160–200 μm fraction—initially demonstrated the highest noise reduction coefficient (NRC), with a maximum NRC of 0.210 at 80 mm powder bed heigh, the modification with AgNP significantly diminished the dependency of sound absorption performance on particle size. Ag-modified samples showed NRC values, CF with a particle size fraction pf 160–200 μm: 0.158, at 80 mm, confirming uniform acoustic performance. Mechanical stiffness, expressed by bulk modulus, increased with both particle size and powder bed density, reaching a maximum of 64.26 MPa for CF_160200_2 PS_Ag. Leaching tests under static, dynamic, and rotation conditions revealed limited silver release, with only slightly increased leaching observed for larger particles under rotation. Silver release from CF_160200_2 PS_Ag was 0.007 wt% (static), 0.008 wt% (dynamic), and 0.010 wt% (rotation). Overall, Ag release remained low, confirming high material stability. These results show that silver-modified CF retain their structural and chemical integrity, offer tunable acoustic and mechanical properties, and show excellent potential for long-term use in environmental remediation, sound insulation, and catalytic applications.This paper was created as part of the project No. CZ.02.01.01/00/22_008/0004631. Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the EU and state budget of the Czech Republic and was prepared with the financial support of the EU under the REFRESH \u2013 project number CZ.10.03.01/00/22_003/0000048 via the Operational Programme Just Transition.EU [CZ.10.03.01/00/22_003/0000048
EASE-ing into global optimization with LLMs : A competition entry on LLM-designed evolutionary algorithms at the Genetic and evolutionary computation conference (GECCO) 2025
No full textThis paper presents an extended abstract describing an entry into the LLM for evolutionary algorithms tailored benchmarking competition using a GNBG-generated test suite. This study explores the generative design of optimization algorithms using large language models (LLMs) within the EASE modular framework, which supports iterative prompting and feedback-driven refinement. Across five successive generations, we observed a progressive transformation in algorithmic structure. The findings suggest opportunities for further research into the role of prompt design, feedback phrasing, and framework architecture in guiding the emergence of more task-adaptive, domain-specialized algorithmic behavior.The research presented in this paper was partially supported by the Internal Grant Agency of Tomas Bata University in Zlin under project number IGA/CebiaTech/2023/004, and by resources of the A.I.Lab at the Faculty of Applied Informatics, Tomas Bata University in Zlin (ailab.fai.utb.cz). Additional support was provided by the Polish Ministry of Education and Science funds assigned to AGH University of Krakow, and further by program \u201CExcellence initiative\u2014research university\u201D for the AGH University in Krakow as well as the ARTIQ project
Effect of polymer grafting on the tribological performance of graphene oxide under ambient air and vacuum
No full textGraphene is known to be an excellent lubricant in a dry air or vacuum environment; however, the modification of its surface chemistry and friction properties is a challenging task. In contrast, mono- and few-layered graphene oxide (GO) offers easier modulation of its surface properties, but its tribological properties under vacuum are currently unknown. In this work, the impact of GO modification by poly(methyl methacrylate) (PMMA) and poly(trifluoroethyl methacrylate) (PTFEMA) on the friction in ambient air and vacuum conditions has been investigated. The polymer chains were grafted from GO layers under surface-initiated atom transfer radical polymerization conditions followed by spin-coating on the sapphire substrates. The ambient air ball-on-disk investigations prove a good lubrication effect of all of the coatings as compared to the bare sapphire substrate. Modified GO shows a lower friction coefficient (COF) as compared to pristine GO (0.16–0.19 and 0.23, respectively) and up to five times longer steady-state friction stage, which is caused by the formation of the tribolayer, decreasing the surface hydrophilicity and probability of the debris agglomeration. In the vacuum, all samples show a COF ranging at 0.02–0.05. The observed difference is caused by morphological changes in the sliding contact. Generation of buckling ribbons on the sapphire surface in GO and PMMA-modified samples reduces the COF to 0.02–0.03, whereas an inhomogeneous tribolayer formed in PTFEMA-modified samples increases the COF to 0.05. Our results illustrate that grafting of the GO layers can improve the lifetime of the applications in ambient air, while it induces sliding mechanisms that can enhance the properties of the applications working in vacuum conditions.This work was funded by the EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia under Project No. 09I03-03-V04-00709 and the Research and Development Agency under the contracts APVV-19-0338, APVV-23-0534 and APVV-21-0231. M.I. and J.O. acknowledge the Ministry of Education, Youth and Sports of the Czech Republic \u2013 DKRVO (RP/CPS/2024-28/003) and VEGA 2/0137/23.European Commission [09I03-03-V04-00709]; EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia [APVV-19-0338, APVV-23-0534, APVV-21-0231]; Research and Development Agency [RP/CPS/2024-28/003, VEGA 2/0137/23]; Ministry of Education, Youth and Sports of the Czech Republi
Photoluminescence of epoxy resin: explanation of the increase in the flux of photoluminescent radiation during the initial stage of the curing process
Get PDFWhen using luminescence spectroscopy to study the curing of epoxy resins, there is an increase in the luminescent radiant flux at the beginning of the curing process. The paper clarifies this phenomenon, which limits the determination of the fundamental kinetic constants of the chemical crosslinking reaction. The reflectance measurement shows that the mentioned phenomenon is of physical origin and is caused by a change in the refractive index of the mixture after the addition of the hardener. This change in refractive index is significant in the context of luminescence spectroscopy as it affects the observed luminescent radiant flux. There is a decrease in the refractive index and, therefore, a decrease in reflectance at the material-atmosphere interface, which causes an increase in the number of photons that leave the material. This assumption was further confirmed by measuring the refractive index for the given wavelengths and by the calculation. The paper provides a method of estimating the time constant of the physical process of increase in the flux of photoluminescent radiation. Therefore, it is possible to determine when this process ends, which is crucial for the subsequent estimation of the kinetic parameters of the chemical curing.This work was supported by the Faculty of Applied Informatics, Tomas Bata University in Zl\u00EDn, under project RVO/CEBIA/2024/003. The authors thank Prof. Zme\u0161kal from the Faculty of Chemistry BUT for measuring refractive indices using an ellipsometer.Faculty of Applied Informatics, Tomas Bata University in Zlin [RVO/CEBIA/2024/003
Technology for evaluating and selecting coworking spaces according to clients' target needs
Get PDFThe main goal of this study is to develop a technology for evaluating and selecting coworking spaces (CS) according to the target needs of clients. For this purpose, the following were developed: a fuzzy model for evaluating coworking; a model for aggregating the output data of the fuzzy model for evaluating coworking and the target needs of clients; a validation of the study based on 5 coworking spaces is presented. The research is based on the apparatus of fuzzy sets, which allows one to increase the degree of validity of decisions. The input data are given in estimation intervals that consider all possible scenarios. An intellectual analysis of knowledge is used to process input information, the subjectivity of experts is revealed, and the final assessment is presented in quantitative form. The value of the model is that it allows one to obtain a quantitative assessment of CS from input fuzzy expert data, and the assessment procedure for experts is simple and natural. The model considers the users' goals regarding an environment that increases work productivity, namely: environmental goals, social goals, and innovation goals. At the model's output, we have an initial quantitative assessment and a ranking series of CS. The research that was conducted contributes to the development of CS, increasing its efficiency and compliance with market needs. It is also useful for freelancers, startup teams, and small businesses, who receive a tool for choosing a space that meets their needs in terms of location, budget, and conditions
Motivations and consequences of psychological ownership in rental commerce: evidence from the Gen Z consumers
No full textGrounded on the psychological ownership (PO) theory and generational cohort theory, the study examines the motivations shaping the PO of rental commerce offerings among Generation Z consumers. Distinct from prior studies, the work also examines PO’s behavioural consequences particularly on perceived misbehaviour intentions and sustainable consumption behaviour. An online scenario-based survey was deployed for data collection, involving 256 Gen Z consumers in the Philippines. Partial least squares structural equation modelling (PLS-SEM) technique was used for data analysis. The findings suggest that self-identity and the sense of belonging positively and significantly affect PO of rental commerce offerings. Meanwhile, PO positively and significantly affects perceived misbehaviour intentions and sustainable consumption behaviour. The study argues that there is a need to reinforce PO formation to curtail misbehaviour tendencies, instil a sense of responsibility to protect and care for leased products, and nurture sustainable consumption behaviour.The authors are thankful to the Internal Grant Agency of FaME through Tomas Bata University in Zlin No. IGA/FaME/2021/003 (Consumer behaviour and performance management of firms in a competitive digital world) for financial support to carry out this research and IGA/FaME/ 2022/007 (An investigation of housing affordability in the regions of the Czech Republic: Implications of income segregation, tourism & short-term rentals and smart cities)
The intersection of ecological leadership and GHRM: A blueprint for a circular economy
Get PDFThe circular economy now plays a crucial role in addressing ecological challenges. The exact function of green human management (GHRM) in transitioning to a circular economy has yet to be determined. Manufacturing firms are taking steps to enhance their sustainability practices to support the circular economy. The relationship between organizational green actions and GHRM in the transition to a circular economy remains uncertain. This study intends to discover the relationship among manufacturing firms’ ecological leadership, green HR practices, green innovations, and circular economy models to enhance sustainable performance. 234 survey questionnaires from Pakistani small and medium-sized manufacturing industries were evaluated using structural equation modelling with partial least squares. GHRM had a positive and significant impact on circular economy and green innovation actions, as shown by the findings. This framework is specifically designed for manufacturing SMEs in Pakistan. The architecture can be adapted to different industries with minor modifications. The study may be biased due to its reliance on management and specialists. This study’s findings will significantly contribute to human resources managers and SME owner-managers by clarifying the significance and interplay of essential green innovation components and GHRM. This will enlighten awareness of ecological leadership, circular economy, and GHRM practices for sustainable performance. The proposed framework simplifies the connection between ecological leadership, GHRM components, and circular economy for practitioners and decision-makers. Environmental leaders effectively encourage businesses to invest in proactive environmental strategies, lower pollution control, and enhance the performance of green innovation, all while promoting a green image and advancing environmental protection practices. This study determines the appropriate relationship between ecological leadership, circular economy, and GHRM components in the limited Pakistani manufacturing SME environment
Role of developmental culture in inbound open innovation: Mediation role of commitment based HRM practices
No full textThis research, grounded on the resource-based view theory, examines the impact of developmental culture on inbound open innovation in small and medium-sized enterprises (SMEs) in Albania. Using a quantitative survey, data were collected from a sample of 179 service and manufacturing SMEs. The study demonstrates that there is a significant relationship between developmental culture and commitment-based HRM and inbound open innovation, as revealed by the analysis of quantitative survey data using PLS-SEM in SmartPLS 3.0. Moreover, commitment-based HRM serves as an intermediary between a culture that promotes growth and the process of incorporating external ideas and knowledge into an organization, known as inbound open innovation. The results highlight the necessity of transitioning towards cultivating organizational cultures that encourage collaboration and the sharing of knowledge in order to stimulate innovation. Open innovation is recognized as a crucial factor in generating value, enhancing competitiveness, and fostering economic progress. It is recommended that policymakers and industry practitioners embrace new strategies that value openness and collaboration in order to promote the dissemination of innovation and promote sustainable growthTomas Bata University, Zlin, internal grants, FaME TBU [IGA/FaME/2023/012
A numerical comparison of infinite-spectrum-shaping techniques when controlling stable and unstable dead-time systems via the standard PID controller
No full textThis contribution aims to compare several numerical techniques for optimizing or shaping the infinite spectrum of system poles. These techniques use a quasi-continuous shifting of the dominant poles. One of the methods (Quasi-Continuous Pole Shifting) attempts to minimize the spectral abscissa, while the simultaneous goals of the other two methods (Quasi-Direct Pole Placement and Zero-Pole Placement Shifting) are to place the desired root loci and reach the minimum abscissa of the remaining spectrum. The framework problem of the infinite spectrum shaping is interpreted as a feedback control of habitual finite-dimensional stable, integrative, and unstable systems with dead time (i.e., the input-output delay) controlled by the standard Proportional-Integral-Derivative (PID) controllers in this contribution. In addition, the obtained results are also benchmarked with some well-established and recent PID controller tuning methods designed to optimize selected performance measures. Surprisingly, the spectral shaping techniques surpass them in some cases.This research was financially supported by the College of Polytechnics Jihlava
The impact of phosphate- and citrate-based emulsifying salts on processed cheese techno-functional properties: A review
No full textProcessed cheese is a dairy product made by heating and mixing natural cheese with emulsifying salts (sodium phosphates, polyphosphates, and citrates) to create a smooth and homogeneous cheese matrix. Adding emulsifying salts improves the emulsifying capacity of proteins (caseins), enhancing their ability to act as emulsifiers. Furthermore, processed cheese can contain various ingredients, focusing on nutrient content modification and techno-functional properties improvement, resulting in a final product with the desired properties. This review paper provides a comprehensive point of view of the existing information regarding emulsifying salt applications in manufacturing processed cheese and their impact on processed cheese quality and techno-functional properties. In particular, the ion exchange phenomenon, pH adjustment and stabilization, and creaming processes were detailed for solely applied emulsifying salts, and their binary and ternary mixtures. The prospects of emulsifying salts replacement were also considered. Generally, processed cheese's consistency (evaluated in terms of textural and rheological parameters) depends on the composition of emulsifying salts mixtures (ratios of sodium monophosphate, sodium diphosphate, sodium polyphosphate, and sodium citrate). The information summarized in this review could serve as a tool for the dairy industry to help appropriately select emulsifying salts for manufacturing processed cheese with desired properties. Future perspectives on emulsifying salt usage in processed cheese could include evaluating their role in improving nutritional profiles, enhancing functional properties, and addressing specific dietary requirements