Tomas Bata University in Zlín
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Multifunctional bandgap-reduced ZnO nanocrystals for photocatalysis, self-cleaning, and antibacterial glass surfaces
Get PDFA set of ZnO nanocrystals assembly with tuneable reduced bandgaps was prepared via thermal decomposition of ZnO2 precursor. A detailed Raman and EPR analysis revealed ZnO rich in oxygen vacancies with concentration varying upon annealing temperature. The structural defect features corroborated with the bandgap variations indicate photocatalytic response in the visible-light, which was evaluated by using monochromatic LEDs (377, 401, and 429 nm wavelengths) for a correct assessment of the photocatalytic activities of samples in the close vicinities of their bandgaps. It was revealed, that bandgap reduced ZnO exhibits only little yet negligible pho-tocatalytic activity towards Methylene Blue discoloration under 429 nm diode. The Photocatalytic experiments using scavengers support the model that oxygen vacancies easily trap photo-excited electrons (whether VO+ and VO++ state) and, if the energy level of this donor state is close enough, the trapped electron could easily thermalize to the conduction band as well as recombine with photo-excited holes. Furthermore, oxygen vacancies rich ZnO nanocrystals treated glasses were prepared and their photocatalytic-induced self-cleaning property, wettability, and antibacterial activities were evaluated under both UV and visible-light. Besides excellent antibacterial activities against both S. aureus and E. coli, which was achieved even in dark, both photocatalytically-induced self-cleaning ability and wettability provided yet another indirect evidence of the inability of bandgap-reduced ZnO to become activated under visible-light irradiation.RP/CPS/2022/002, RP/CPS/2022/007; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMTMinistry of Education, Youth and Sports of the Czech Republic - DKRVO [RP/CPS/2022/007, RP/CPS/2022/002
Dynamic behavior of thermally affected injection-molded high-density polyethylene parts modified by accelerated electrons
Get PDFPolyethylenes are the most widely used polymers and are gaining more and more interest due to their easy processability, relatively good mechanical properties and excellent chemical resistance. The disadvantage is their low temperature stability, which excludes particular high-density polyethylenes (HDPEs) for use in engineering applications where the temperature exceeds 100 degrees C for a long time. One of the possibilities of improving the temperature stability of HDPE is a modification by accelerated electrons when HDPE is cross-linked by this process and it is no longer possible to process it like a classic thermoplastic, e.g., by injection technology. The HDPE modified in this way was thermally stressed five times at temperatures of 110 and 160 degrees C, and then the dynamic tensile behavior was determined. The deformation and surface temperature of the specimens were recorded by a high-speed infrared camera. Furthermore, two thermal methods of specimen evaluation were used: differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The result of the measurement is that the modification of HDPE by accelerated electrons had a positive effect on the dynamic tensile behavior of these materials.IGA/FAI/2022/005; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: CZ.02.2.69/0.0/0.0/18_053/001787European Structural and Investment Funds, Operational Programme Research, Development and Education under the project The Development of Capacity for Research and Development of TBU in Zlin [CZ.02.2.69/0.0/0.0/16_028/0006243]; Ministry of Education, Youth and Sports under the project International mobility of UTB researchers in Zlin II [CZ.02.2.69/0.0/0.0/18_053/001787]; Internal Grant Agency of Tomas Bata University [IGA/FAI/2022/005
Electrical detection of vibrations of electrospun PVDF membranes
Get PDFWe prepared electroactive PVDF membranes, which were subjected to mechanical as well as dual electro-mechanical signals and their responses were detected by the evoked electrical pulses. The aim was to obtain primarily electric energy that could be used for light signalling, sensing of the membrane properties and membrane motion detection. The obtained data showed the unique as well as usable properties of PVDF membranes. From this point of view, the gain and analysis of the electrical responses to combined electro-mechanical loads of PVDF membranes have been important in terms of identifying the mechanism. The detected electrical response of the PVDF membrane to their electro-mechanical pulses also indicated the possibility of using this phenomenon. Among others, it suggests monitoring of membrane fouling and use for a self-cleaning mechanism.RP/CPS/2022/007; Tomas Bata University in Zlin, TBU: IGA/CPS/2020/008, IGA/CPS/2021/003Ministry of Education, Youth and Sports of the Czech Republic DKRVO [RP/CPS/2022/007]; TBU in Zlin [IGA/CPS/2020/008, IGA/CPS/2021/003
Exploring adaptive components of SOMA
No full textThis research paper aims to explore the possibilities of parameterization of state-of-the-art adaptive mechanisms incorporated in the self-organizing migrating algorithm (SOMA). This algorithm has gained renewed interest from the research community while the algorithm’s internal dynamics, mechanisms, and dependencies of the functionality on parameter settings have not been thoroughly examined using a data-driven approach. Our extensive test workflow has yielded valuable insights into the performance of the SOMA and its sensitivity to parameter settings that affect the migration of individuals. Important findings were also obtained regarding the appropriate parameter settings required for more complex techniques such as clustering, organization, and population restart. The research also highlighted the influence of different modern adaptation techniques and the suitability of combining different modern adaptation mechanisms, leading to the modular design of different configurations. The simulation experiments conducted provided new insights that could be useful for further research, especially with the rapid development in automatic configurators of metaheuristic algorithms, modular concepts of algorithms, and their performance prediction.Faculty of Applied Informatics, Tomas Bata University in Zlin; Tomas Bata University in Zlin, TBU, (IGA/CebiaTech/2023/004); Grantová Agentura České Republiky, GA ČR, (GF21-45465L)Czech Science Foundation (GACR) [GF21-45465L]; Internal Grant Agency of the Tomas Bata University in Zlin [IGA/CebiaTech/2023/004
Leveraging Large Language Models for the generation of novel metaheuristic optimization algorithms
No full textIn this paper, we investigate the potential of using Large Language Models (LLMs) such as GPT-4 to generate novel hybrid swarm intelligence optimization algorithms. We use the LLM to identify and decompose six well-performing swarm algorithms for continuous optimization: Particle Swarm Optimization (PSO), Cuckoo Search (CS), Artificial Bee Colony (ABC), Grey Wolf Optimizer (GWO), Self-Organizing Migrating Algorithm (SOMA), and Whale Optimization Algorithm (WOA). We leverage GPT-4 to propose a hybrid algorithm that combines the strengths of these techniques for two distinct use-case scenarios. Our focus is on the process itself and various challenges that emerge during the use of GPT-4 to fulfill a series of set tasks. Furthermore, we discuss the potential impact of LLM-generated algorithms in the metaheuristics domain and explore future research directions.Faculty of Applied Informatics, Tomas Bata University in Zlin; Tomas Bata University in Zlin, TBU, (IGA/CebiaTech/2023/004
The contribution of the European NIS2 directive to the design of the cyber security model
No full textThe article discusses the possible effects of Directive 2022/2555 of the European Parliament (EU) and of the Council of 14 December 2022 on measures to ensure an ordinary high level of cyber security in the Union and amending Regulation (EU) No. 910/2014 and Directive (EU) 2018 /1972 and on the repeal of Directive (EU) 2016/1148 (NIS2 Directive) and subsequently to it on the Act on Cybersecurity and on the amendment of related laws (Act on cyber security), which will have to be amended concerning the NIS2 directive and their possible impacts on information security management systems (ISMS policies). The contribution aims to describe the current state of implementation of the NIS2 directive into the legal environment using the example of the Czech Republic. To outline the possible procedure of applying the implemented directive into practice and possible impacts on subjects
On the stabilization of emulsions by cellulose nanocrystals and nanofibrils: Interfacial behavior and synergism
Get PDFCompetitive adsorption of cellulose nanofibers at oil-water interface in Pickering emulsion is reported here. Dodecane-in-water emulsions stabilized by either of two types of nanocelluloses, cellulose nanocrystals (CNC) or cellulose nanofibrils (CNF), as well as by their binary mixtures with increasing fractions of CNC, were prepared using particle concentrations of 0.1–0.5 wt% and studied. Despite differences in shape and morphology, both forms of nanofibers produced stable emulsion droplets even at low particle concentrations (0.1 wt%), with CNC producing smaller droplets and emulsions with higher stability. When mixed, an increased fraction of CNC in the mixture reduced the average droplet size, which however applied only for higher contents of oil (30 and 50 wt%) and higher total contents of cellulose particles used under emulsification. The CNC particles controlled the size of emulsion droplets, while the role of CNF contributed to the further surface coverage. When the fraction of CNF in the mixture increased, the capability of CNC particles to readily adsorb at the oil-water interface was reduced by the CNF nanofibrils present in aqueous phase. The stability of emulsions with respect to changes in droplet size and creaming index was influenced more by oil content and total particle concentration than by the fraction of CNC present in the mixture.Ministry of Education , Youth and Sports of the Czech Republic DKRVO, (RP/CPS/2022/001, RP/CPS/2022/002); Ministry of Education, Youth and Sports of the Czech Republic DKRVO; TBU in Zlin, (IGA/CPS/2020/002); Grantová Agentura České Republiky, GA ČR, (23-07425S)Czech Science Foundation [RP/CPS/2022/001]; Ministry of Education, Youth and Sports of the Czech Republic DKRVO [RP/CPS/2022/002, IGA/CPS/2020/002]; Internal Grant Agency of TBU in Zlin; [23-07425S
The influence of sulfur dioxide concentration on antioxidant activity, total polyphenols, flavonoid content and individual polyphenolic compounds in white wines during storage
Get PDFWines represent a rich source of bioactive compounds, especially polyphenolic compounds, which mostly contribute to the antioxidant activity. Sulfur dioxide (SO2) has mostly been used as a preservative in winemaking to prevent oxidation during storage. The aim of this paper is to evaluate the changes in SO2 levels and the influence of sulfur dioxide addition at seven different concentrations on the antioxidant activity (detected by DPPH-2,2-diphenyl-1-picrylhydrazyl and the ABTS Trolox equivalent antioxidant capacity methods), total polyphenols, flavonoid content and individual polyphenolic compounds (determined by the HPLC high-performance liquid chromatography method) of white wines during 5 months of storage. The assayed sulfur dioxide concentrations show a decreasing tendency with time, with a final decrease of more than 50% in comparison with the start of the experiment. Between the first and second measurements, the average decrease in sulfur dioxide was 16%. In the following interval, it was found that the maximum decline in SO2 was 26%. The changes in SO2 levels cannot be considered statistically significant. At the same time, we observed a decreasing tendency in the TPC content during storage. The antioxidant activity determined by the DPPH method at the beginning of the experiment ranged from 116.75 up to 270.62 mg & BULL;L-1, while the antioxidant activity increased with sulfur dioxide concentration. The AA detected by the ABTS method displayed a decreasing tendency during storage. In the case of the TFC content, we observed a significant influence of sulfur dioxide on the concentration. No addition or addition of high SO2 concentrations negatively influenced the flavonoid content in the samples. During storage, we observed a highly variable content of phenolic compounds in relation to SO2 addition. The most abundant compounds were chlorogenic acid, caffeic acid and epigallocatechin.internal grant of Tomas Bata University in Zlin [IGA/FT/2023/003
Revisiting ab initio carcinoembryonic antigen and CA19-9 tumor markers in colorectal carcinoma in association with anatomotopographic location and staging of disease
Get PDFOBJECTIVE: This study purposed to evaluate preoperative two tumor markers, namely, carcinoembryonic antigen and carbohydrate antigen (CA)19-9, in colorectal cancer for anatomotopographic location with disease stage and to assess their utility for diagnostic staging purposes.
METHODS: The study retrospectively incorporated patients who had undergone surgery for colorectal cancer at our department in 2015-2018 and in whom carcinoembryonic antigen and CA19-9 tumor markers had been preoperatively analyzed. The obtained data were then statistically processed using R-project.
RESULTS: A total of 155 patients had been incorporated, of whom 96 (62%) were men and 59 (38%) were women. Rectum was the most common location (74 patients, 48%), and the least represented stage was IV (18, 12%). The marker carcinoembryonic antigen was obtained in all 155 cases, while CA19-9 was in 105. The median carcinoembryonic antigen was 3 (0.34-1104.25), and the median CA19-9 was 12 (0.18-840.00). A significance was recognized between median carcinoembryonic antigen and disease stage (p-value=0.016), with stages I, II, and III (medians 2, 3, and 2) different from stage IV (median 13), while no significance for CA19-9 was recognized (p-value=0.343). No significance between either marker and location (carcinoembryonic antigen: p=0.276; CA19-9: p=0.505) was detected. The testing was performed at a significance level of alpha=0.05.
CONCLUSION: This study revealed a significance between the marker carcinoembryonic antigen, but not CA19-9, and the disease stage, while no relationship of either of these markers with tumor location was found. Herewith, the study confirmed that higher carcinoembryonic antigen values may suggest the finding of more advanced forms of colorectal cancer and thus a worse prognosis of this malignant phenomenon
Harnessing the power of virtual reality: Enhancing telepresence and inspiring sustainable travel intentions in the tourism industry
Get PDFThis study investigates how virtual reality (VR) can enhance telepresence and stimulate VR use and travel intentions in the sustainable tourism industry. 512 local and international tourists in Vietnam participated in an online survey after experiencing a VR experiment. They interacted with an app presenting a sustainable tourist destination based on nature, with the treatment group using VR sets and the control group viewing it on a 2D screen. Results indicate that VR-based tours facilitate greater telepresence than 2D presentations. VR is not a substitute for actual travel, with higher intentions reported to use VR in the future and to visit the tourist destination in real life due to their greater telepresence and perceived enjoyment from VR. This has implications for nature-based sustainable tourism, with further research needed for other types of tourism, including extreme activities