Tomas Bata University in Zlín
Institutional repository of Tomas Bata University LibraryNot a member yet
10673 research outputs found
Sort by
A perfect knife—Bulk decompilation and preprocessing tool
No full textDue to its vast popularity, the Android operating system has quickly become the main target of mobile malware creators. Consequently, there is a huge need for intensive efforts in the research of Android malware applications to identify malware features and thus be able to create an efficient method for malware detection. One of the main issues related to malware research is obtaining reliable datasets. Malware datasets could be obtained from various sources. Not only that they can tally up to thousands of individual applications, but also can contain damaged, corrupted, or otherwise invalid files. A large number of applications in a dataset is nearly impossible to be processed manually, invalid files can also jeopardize the process of analysis. For the results to be reproducible there needs to be a way how to specify which dataset was used and that it contained only valid files. This work introduces a tool, Perfect Knife, created by our research team for automatised decompilation, dataset validation, unification, and preparation for further research purposes
Current challenges in operation, performance, and maintenance of photovoltaic panels
Get PDFThe installed solar capacity in the European Union has expanded rapidly in recent years. The production of these plants is stochastic and highly dependent on the weather. However, many factors should be considered together to estimate the expected output according to the weather forecast so that these new PV plants can operate at maximum capacity. Plants must be operated in coordination with maintenance operations and considering actual energy market prices. Various methods have recently been developed in the literature, ranging from the most impactful artificial-intelligence-based generation estimation methods to various diagnostic and maintenance methods. Moreover, the optimal operational and maintenance strategy usually depends on market regulation, and there are many concerns related to the distribution system operator. This review article aims to summarize and illustrate the challenges of operating and maintaining solar power plants and the economic and technical importance of these problems
Para–phenylenediamine dimer as a redox–active guest for supramolecular systems
No full textRedox–active components are highly valuable in the construction of molecular devices. We combined two p-phenylenediamines (p-PDA) with a biphenyl (BiPhe) unit to prepare a supramolecular guest 4 consisting of three binding sites for cucurbit[7/8]uril (CBn) and/or cyclodextrins (CD). Supramolecular properties of 4 were investigated using NMR, UV-vis, mass spectrometry and isothermal titration calorimetry. Our analysis revealed that 4 forms higher–order host–guest complexes, wherein a CD unit occupies the central BiPhe site, secured by two CBn units at the terminal p-PDA sites. Additionally, 1 : 1 complexes with α-CD and β-CD, a 1 : 2 complex with γ-CD and 2 : 1 complexes with CB7 and CB8 were identified. Through UV-vis and cyclic voltammetry, redox processes leading to the formation of a stable, deep blue dication diradical of 4 are elucidated. Furthermore, it is demonstrated that CB7 selectively protects oxidised 4 from reduction in the presence of a reducing agent. The supramolecular and redox properties of the structural motif represented by 4 render it an interesting candidate for the construction of supramolecular devices.Internal Funding Agency of TBU in Zlin [IGA/FT/2023/001]; Deutsche Forschungsgemeinschaft - MEYS CR [LM2023042
Tėvų dalyvavimas vaikui ruošiant namų darbus: „Turiu padėti savo vaikui nepaisydamas jokių COVID-19“
Get PDFThe study deals with parental involvement in the child’s home preparation. The qualitative research with parents of primary school pupils showed the parental homework attitudes and conditions, and reflected changes and strategies in home preparation during pandemic times. Regardless of any pandemic, the results showed differences in homework management; nevertheless, parental help directs to achieve independence and responsibility for the child’s learning, no matter the pandemic.Tomas Bata University in Zlín, TBU, (RVO/FHS/2022/002
Analysis of stylistic and grammatical errors in PhD students' research paper manuscripts
Get PDFThe ability to publish research papers is a must for scientists nowadays. Ideally, at the very beginning of their career, young researchers, PhD students, should be instructed in writing research papers and should get feedback on their texts. In this study, the first manuscripts from 22 doctoral students, non-native English speakers, 223 pages were analysed for errors in grammar, spelling, punctuation, and style. For each type of error and each student, the average per page was calculated. The most frequent errors were identified in using articles, formal features, missing information, and the use of inappropriate words. Individual students showed significantly different levels, which reflected their previous language training and the approach (responsibility) to completing the task. The results will be used to modify the course in Academic Writing (more attention paid to the most frequent errors) and individual work with students
In situ formed aldehyde-modified hyaluronic acid hydrogel with polyelectrolyte complexes of aldehyde-modified chondroitin sulfate and gelatin: An approach for minocycline delivery
Get PDFPolysaccharides like hyaluronan (HA) and chondroitin sulfate (CS) are native of the brain's extracellular matrix crucial for myelination and brain maturation. Despite extensive research on HA and CS as drug delivery systems (DDS), their high water solubility limits their application as drug carriers. This study introduces an injectable DDS using aldehyde-modified hyaluronic acid (HAOX) hydrogel containing polyelectrolyte complexes (PEC) formed with calcium, gelatin, and either CS or aldehyde-modified CS (CSOX) to deliver minocycline for Multiple Sclerosis therapy. PECs with CSOX enable covalent crosslinking to HAOX, creating immobilized PECs (HAOX_PECOX), while those with CS remain unbound (HAOX_PECS). The in situ forming DDS can be administered via a 20 G needle, with rapid gelation preventing premature leakage. The system integrates into an implanted device for minocycline release through either Fickian or anomalous diffusion, depending on PEC immobilization. HAOX_PECOX reduced burst release by 88 %, with a duration of 127 h for 50 % release. The DDS exhibited an elastic modulus of 3800 Pa and a low swelling ratio (0–1 %), enabling precise control of minocycline release kinetics. Released minocycline reduced IL-6 secretion in the Whole Blood Monocytes Activation Test, suggesting that DDS formation may not alter the biological activity of the loaded drug.European Union [813263]; Marie Curie Actions (MSCA) [813263] Funding Source: Marie Curie Actions (MSCA
Biodegradation of poly-3-hydroxybutyrate after soil inoculation with microbial consortium: Soil microbiome and plant responses to the changed environment
No full textBiodegradable plastics play a vital role in addressing global plastics disposal challenges. Poly-3-hydroxybutyrate (P3HB) is a biodegradable bacterial intracellular storage polymer with substantial usage potential in agriculture. Poly-3-hydroxybutyrate and its degradation products are non-toxic; however, previous studies suggest that P3HB biodegradation negatively affects plant growth because the microorganisms compete with plants for nutrients. One possible solution to this issue could be inoculating soil with a consortium of plant growth-promoting and N-fixing microorganisms. To test this hypothesis, we conducted a pot experiment using lettuce (Lactuca sativa L. var. capitata L.) grown in soil amended with two doses (1 % and 5 % w/w) of P3HB and microbial inoculant (MI). We tested five experimental variations: P3HB 1 %, P3HB 1 % + MI, P3HB 5 %, P3HB 5 % + MI, and MI, to assess the impact of added microorganisms on plant growth and P3HB biodegradation. The efficient P3HB degradation, which was directly dependent on the amount of bioplastics added, was coupled with the preferential utilization of P3HB as a carbon (C) source. Due to the increased demand for nutrients in P3HB-amended soil by microbial degraders, respiration and enzyme activities were enhanced. This indicated an increased mineralisation of C as well as nitrogen (N), sulphur (S), and phosphorus (P). Microbial inoculation introduced specific bacterial taxa that further improved degradation efficiency and nutrient turnover (N, S, and P) in P3HB-amended soil. Notably, soil acidification related to P3HB was not the primary factor affecting plant growth inhibition. However, despite plant growth-promoting rhizobacteria and N2-fixing microorganisms originating from MI, plant biomass yield remained limited, suggesting that these microorganisms were not entirely successful in mitigating the growth inhibition caused by P3HB.Ministry of Education, Youth and Sports of the Czech Republic; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Ministry of Agriculture of the Czech Republic, (MZE-RO1724, 90254)Ministry of Education, Youth and Sports of the Czech Republic [FCH-S-24-8591, 90254]; Ministry of Agriculture of the Czech Republic [MZE-RO1724
The impact of surface roughness on conformal cooling channels for injection molding
Get PDFInjection molding technology is widely utilized across various industries for its ability to fabricate complex-shaped components with exceptional dimensional accuracy. However, challenges related to injection quality often arise, necessitating innovative approaches for improvement. This study investigates the influence of surface roughness on the efficiency of conformal cooling channels produced using additive manufacturing technologies, specifically Direct Metal Laser Sintering (DMLS) and Atomic Diffusion Additive Manufacturing (ADAM). Through a combination of experimental measurements, including surface roughness analysis, scanning electron microscopy, and cooling system flow analysis, this study elucidates the impact of surface roughness on coolant flow dynamics and pressure distribution within the cooling channels. The results reveal significant differences in surface roughness between DMLS and ADAM technologies, with corresponding effects on coolant flow behavior. Following that fact, this study shows that when cooling channels’ surface roughness is lowered up to 90%, the reduction in coolant media pressure is lowered by 0.033 MPa. Regression models are developed to quantitatively describe the relationship between surface roughness and key parameters, such as coolant pressure, Reynolds number, and flow velocity. Practical implications for the optimization of injection molding cooling systems are discussed, highlighting the importance of informed decision making in technology selection and post-processing techniques. Overall, this research contributes to a deeper understanding of the role of surface roughness in injection molding processes and provides valuable insights for enhancing cooling system efficiency and product quality.Internal Grant Agency of Tomas Bata University in Zlin, (IGA/FT/2024/003)Internal Grant Agency of Tomas Bata University in Zli
The degradation of poly(1-butene) extrudates subjected to artificial and natural aging
Get PDFIn this work, we examined the degradation behavior of isotactic poly(1-butene) (PB-1) under artificial aging and natural weathering conditions. PB-1 samples underwent accelerated aging through UV irradiation and natural weathering. Chemical and structural changes in the degraded samples were characterized using Fourier-transform infrared–attenuated total reflectance (FTIR–ATR) spectroscopy, surface analysis, and wide-angle X-ray scattering (WAXS). The mechanical properties were evaluated via tensile testing. FTIR–ATR analysis revealed the presence of carbonyl groups in the degraded samples, indicating oxidative degradation. Surface observations employing scanning electron microscopy (SEM) revealed the formation of surface cracks in both samples, with differing crack initiation mechanisms. The two aging methods affected the mechanical properties of the samples: artificial aging induced a gradual reduction in both tensile modulus and strength, whereas natural weathering engendered a marginal increment in modulus alongside diminished strength. Additionally, elongation-at-break value witnessed a marked decrease in both sample sets during the preliminary stages of degradation. This work employed accelerated time equivalent, obtained by juxtaposition of the values of carbonyl index during both artificial aging and natural weathering and their interpolation to determine the degradation rate and adequately to correlate the final properties of the aged PB-1. It was observed that surface morphology and mechanical attributes of degraded samples were subject to additional influences such as temperature, humidity, and precipitation during natural weathering. This research work provided significant insights into PB-1 degradation mechanisms and effect of different aging conditions on its performance.National Technical Library in Prague, (IGA/FT/2023/008)IGA/FT/2023/008 [IGA/FT/2023/008
The specifics of the return of Czech tourism to the positives of the pre-COVID-19 era
Get PDFThe present study directs attention to the impact of the COVID-19 pandemic on one of the most complex and globally significant economic sectors, tourism. Significant losses in the tourism economy were also recorded in the Czech Republic, for which tourism was one of the most affected sectors. However, the pandemic also revealed the need to be prepared and have a plan to develop tourism effectively and to be able to solve unexpected problems. The question remains whether the Czech tourism industry managed to overcome the reflection of the impact of the pandemic in the critical year 2020 in continuity with a negative spillover into 2021 and subsequently build on the significantly positive development trend of the successful year 2019. A study based on a thorough comparison of secondary data, following on from the analysis of data from the Czech Statistical Office, presents not only a comprehensive reflection of the impact of the pandemic on tourism in connection with the specifics of the Czech environment but also points to a solution. The importance of tourism for the Czech economy is indisputable. Although it is a beneficial finding that "Czechs have rediscovered the Czech Republic," it is necessary to strengthen interest both on the part of foreign visitors (e.g., by satisfying the demand for specific topics such as food, events, LGBT tourism, etc.), and to gain the attention of investors and entrepreneurs