Tomas Bata University in Zlín
Institutional repository of Tomas Bata University LibraryNot a member yet
10673 research outputs found
Sort by
Effect of polyurethane structure on arsenic adsorption capacity in nanofibrous polymer/ferrous sulphate-based systems
No full textThis study investigates the effect of the nanofibrous polymeric structure of an adsorptive material, modified with an immobilized inorganic sorbent based on ferrous sulphate, on the capacity of the material to remove arsenic from contaminated water. Nanofibrous materials were prepared by electrospinning from polyurethane types selected using a primary adsorption test. The functional groups and chemical composition (FTIR, EDX), morphology (SEM, porometry) and hydrophilicity (contact angles) of the prepared nanostructured materials were determined in order to assess the effect of composition and structure on the removal of arsenic. The process of arsenic removal was monitored by atomic absorption spectroscopy (AAS). It was found that certain samples of polyurethanes, particularly self-synthesized aromatic polyurethane of an ester type, PU918, could remove arsenic by complexation on nitrogen in their polymer chains. The greatest efficiency for arsenic removal was ca. 60% (initial cAs = 150 μg L−1). It was also found that adding even a small amount (1 wt%) of an inorganic adsorbent based on ferrous sulphate into the fibre mass of the nanofibrous structure would increase the efficiency up to 90% as a result of a chemical reaction between the additive and arsenic ions. The extent and rate of adsorption were described by kinetic and isotherm models. The adsorption process is well characterized by a pseudo-second-order kinetic model and both Freundlich and Langmuir isotherm models. High adsorption capacity and rate are the basis for the use of nanofibrous material in filters for arsenic separation. © 2022 The Royal Society of Chemistry.Technological Agency of the Czech Republic [TJ02000269]; Ministry of Education Youth and Sports of the Czech Republic-programme DKRVO [RP/CPS/2022/002]Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2022/002; Technologická Agentura České Republiky: TJ0200026
A novel alternative to free oil remediation and recovery: Foamy absorbents designed from low molecular paraffinic waste
Get PDFThis study focuses on preparing porous, hydrophobic, and oleophilic hydrocarbon-based foams applicable for removing free oils from water surfaces. Paraffinic waste material generated during industrial production of lowdensity polyethylene (Qatar Petrochemical Company) was used for the preparation of foamy, elastic structures through crosslinking of short aliphatic chains by dicumyl peroxide and foaming by 1,1 '-azobiscarbamide. The porosity of the foam determined by computer microtomography was 58.9%, and the bulk density was 0.42 g. cm-3. The sorption ability of the foam was tested using diesel oil, motor oil, and heavy crude oil. The absorption capacity of foam was characterized as the ratio between the mass of oil absorbed by the foam and the mass of a neat foam (Sw) and as the ratio between the volume of oil absorbed by the foam and the volume of a neat foam (Sv). The absorption capacities of the new foam reported in this study (referred to here as Qwax foam) are 6.6 +/- 0.3 g/g, or 3.3 +/- 0.2 cm3/cm3 for diesel oil, 3.9 +/- 0.4 g/g or 1.9 +/- 0.3 cm3/cm3 for motor oil, and 3.4 +/- 0.2 g/g or 1.4 +/- 0.4 cm3/cm3 for crude oil. To compare the sorption ability of Qwax foam with some standard foams, the absorption capacities of highly porous commercial polyurethane (PU) and melamine (MA) foams were investigated under the same conditions. These foams showed much higher sorption capacity considering the Sw parameter as a reference; however, there was a lower sorption capacity compared to parameter Sv. In the last paragraph, the suitability and the relevancy of parameters Sw and Sv for a comparison of the absorption capacity of foams were theoretically analyzed.RP/CPS/2020/003; Qatar National Research Fund, QNRF: NPRP12S-0311-190299; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMTQatar National Research Fund under its National Priorities Research Program [NPRP12S-0311-190299]; ConocoPhillips Global Water Sustainability Center (GWSC); Qatar Petrochemical Company (QAPCO); Ministry of Education, Youth, and Sports of the Czech Republic-DKRVO [RP/CPS/2020/003
Enzyme-catalyzed polymerization process: A novel approach to the preparation of polyaniline colloidal dispersions with an immunomodulatory effect
Get PDFA green, nature-friendly synthesis of polyaniline colloidal particles based on enzyme-assisted oxidation of aniline with horseradish peroxidase and chitosan or poly(vinyl alcohol) as steric stabilizers was successfully employed. Physicochemical characterization revealed formation of particles containing the polyaniline emeraldine salt and demonstrated only a minor effect of polymer stabilizers on particle morphology. All tested colloidal particles showed in vitro antioxidation activity determined via scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. In vitro, they were able to reduce oxidative stress and inhibit the production of reactive oxygen species by neutrophils and inflammatory cytokines by macrophages. The anti-inflammatory effect observed was related to their antioxidant activity, especially in the case of neutrophils. The particles can thus be especially advantageous as active components of biomaterials modulating the early stages of inflammation. In addition to the immunomodulatory effect, the presence of intrinsically conducting polyaniline can impart cell-instructive properties to the particles. The approach to particle synthesis that we employed-an original one using environmentally friendly and biocompatible horseradish peroxidase-represents a smart way of preparing conducting particles with unique properties, which can be further modified by the stabilizers used.Czech Science Foundation [20-28732S]; Ministry of Education, Youth and Sports of the Czech Republic-DKRVO [RP/CPS/2022/001]; TBU in Zlin [IGA/CPS/2022/001]; project OP RDE Junior Grants of TBU in Zlin [CZ.02.2.69/0.0/0.0/19_073/0016941]; European Structural and Investment Funds, Operational Program Research, Development and Education-"Preclinical Progression of New Organic Compounds with Targeted Biological Activity" (Preclinprogress) [CZ.02.1.01/0.0/0.0/16_025/0007381
Cultural influences on future transportation technology usage: The role of personal innovativeness, technology anxiety and desire
Get PDFThis study develops and validates a model, based on personal cultural values theory and psychological research, in relation to technology adoption. The model focuses specifically on the future use of on-demand air mobility (ODAM), which is expected to have significant implications for city commuting and personal well-being in the years ahead. We use a path modelling approach, in addition to recently advanced analytical methods such as the finite mixture partial least squares (FIMIX-PLS), measurement invariance of composite models (MICOM) and multi-group analysis, to validate the model using a data set of 627 young consumers from the Czech Republic. The research model explains 45.2% variation in the future use of ODAM using our global model. This variance explained in the future use of ODAM increases to 62.3% and 64.5% respectively, when we segment our data set into two groups. The results also show that tradition has significant influence on technology anxiety, personal innovativeness and desire to use ODAM. Independence positively affects personal innovativeness but not the desire to use ODAM. We also find that technology anxiety influences the desire to use, which in turn influences the future use of ODAM. However, we find group differences in the influence of ambiguity intolerance on technology anxiety, desire and personal innovativeness. Thus, the study also evaluates the existence of significant differences between two groups in our data set. Overall, the study suggests that individual cultural values play a particularly important role in influencing the future use of ODAM through psychological characteristics. The research implications of the study are discussed in the article.FSR FORD [5-6/2021-23/FaME/003]; [IGA/FaME/2021/003
Social media usage and SME firms' sustainability: An introspective analysis from Ghana
Get PDFSocial media is gradually transforming diverse business ecosystems due to the limitless capabilities they offer. Given this, emerging businesses across the globe are leveraging this innovation to improve their operations. While the literature on the usage of social media by small and medium enterprises (SMEs) is still emerging, the outcomes from existing research have not been coherent. Amid this, limited empirical evidence has been adduced on the affordance of the technology for the SME ecosystem in developing economies, particularly Ghana. Following this, this study aims to fill this research gap by investigating the impact of social media usage on the long-term sustainability of SMEs, specifically in Ghana. Using empirical data from 424 respondents who are representatives of manufacturing SMEs in Ghana, using SmartPLS techniques, the study confirmed that, generally, social media usage does not only have a positive impact on SMEs but drastically drives their motivations towards resilience and sustainability. The results further revealed a positive and significant effect of social media usage value creation, business connections and opportunities on SMEs' sustainability. This study contributes to knowledge of social media usage and sustainability from a developing country's perspective. This study offers several implications for theory and practice.Doctoral Research Innovation Fund Project of CWAS of UESTC [CXJJ2021122504]Ministry of Education of the People's Republic of China, MOE: CXJJ202112250
The effect of application of chicken gelatin on reducing the weight loss of beef sirloin after thawing
Get PDFFreezing is one of the oldest and most-often-used traditional methods to prolong the shelf life of meat. However, the negative phenomenon of this process is the weight loss of water that occurs after the meat is thawed. Together with the water that escapes from the meat during thawing, there are large weight losses in this valuable raw material. Another negative aspect is that mineral and extractive substances, vitamins, etc. also leave the meat, resulting in irreversible nutritional losses of nutrients in the meat, which are subsequently missing for use by the consumer of the meat. The main goal of this work is to reduce these losses by using gelatin coatings. Gelatin was prepared from chicken paws according to a patented biotechnological procedure, which uses the very gentle principle of obtaining gelatin with the usage of enzymes. This unique method is friendly to the environment and innocuous for the product itself. At the same time, it ensures that the required principles achieve a circular economy with the use of the so far very-little-used slaughter byproducts, which in most parts of the world end up in uneconomic disposal by burning or landfilling without using this unique potential source of nutrients. Gelatin coatings on the surface of the beef steak were created by immersing the meat in a solution based on gelatin of different composition. A coating containing 3%, 5% or 8% gelatin with 10% or 20% glycerol (by weight of gelatin) and 1% glutaraldehyde crosslinker (by weight of gelatin) has proved to be effective. The amount of glutaraldehyde added to the coating is guaranteed not to exceed the permitted EU/U.S. legislative limits. In addition to weight loss, meat pH, color and texture were also measured. Freezing was done in two ways; some samples were frozen at a normal freezing temperature of -18 degrees C and the other part of the experiment at deep (shock) freezing at -80 degrees C. Defrosting took place in two ways, in the refrigerator and in the microwave oven, in order to use the common defrosting methods used in gastronomy. A positive effect of this coating on weight loss was observed for each group of samples. The most pronounced effect of coating was found for the least gentle method of freezing (-18 degrees C) and thawing (microwave), with the average weight loss of the coated samples differing by more than 2% from that of the uncoated sample. No negative effect of the coating was observed for other meat properties tested, such as pH, Warner-Bratzler Shear Force (WBSF) or color. Gelatin-based coating has a positive effect on reducing the weight loss of meat after thawing. Chicken gelatin prepared by a biotechnological process has a new application in improving the quality of meat due to the retention of water and nutrients in frozen and subsequently thawed beef, which can contribute to the better quality of the subsequently gastronomically prepared dish, while maintaining the weight and nutritional quality. This also results in economic savings in the preparation of highly-valued parts of beef.Internal Grant Agency of the Faculty of Technology, Tomas Bata University in Zlin [IGA/FT/2021/007, IGA/FT/2022/003]; National Agency for Agriculture Research project [QK1920190]QK1920190; Tomas Bata University in Zlin, TBU: IGA/FT/2021/007, IGA/FT/2022/00
Investigation of the influence of orientation on the tensile properties of 3D printed samples with gyroid structure
No full textThe article deals with experimental testing of a complex shape porous structure called Gyroid with a specific volume ratio Vr = 30 %. The main goal was to investigate the effect of orientation and location of samples on their resulting mechanical tensile properties. All samples were made of ABS-T silver material by 3D printing. Virtual sample models were designed using two different CAD software. Tensile samples were produced in two different directions perpendicular to each other. Five samples were made horizontally, so the vector of the loading tensile force lay in the plane of the printed layer. The other five samples were made vertically, so the sample was loaded perpendicular to the plane of the printed layer. Experimental testing and statistical processing have shown the orientation and direction of the printed layer. Experimental testing and statistical processing have shown that the orientation and direction of 3D printing have a significant impact on the resulting mechanical properties and quality of a component, as well as on the time of the 3D printing process itself. © 2022 IEEE
The influence of the addition of instant rice mash on the textural properties of rice bread
No full textThe effect of instant rice mash (IRC) addition to rice bread was evaluated. Six samples containing different amounts of IRC (0, 10, 20, 30, 40, and 50%) were added to rice dough. Quality parameters (baking loss, specific volume, and textural properties) were evaluated. Texture properties were analysed in fresh bread and in bread after 24 h of storage. Additions of 10% and 20% of IRC increased baking loss from 15% to 22%, and the specific volume of rice bread from 1.5 mL g-1to 2.1 mL g-1(10% of IRC) and 1.9 mL g-1(20% of IRC). Increasing additions of IRC significantly decreased the hardness and chewiness of both fresh bread and bread stored for 24 h. By adding IRC, the cohesiveness of rice bread was increased. These findings are useful for increasing the quality of rice bread by adding IRC to rice dough.Tomas Bata University, Czech Republic [IGA/FT/2021/003]Univerzita Tomáše Bati ve Zlíně: IGA/FT/2021/00
Mineral profile of cricket powders, some edible insect species and their implication for gastronomy
Get PDFEntomophagy is proclaimed as a sustainable nutritional strategy due to the high protein content in edible insects. As it turns out, it may also represent an effective tool for increasing dietary intake of nutrients that are frequently deficient. Cricket powder (CP) appears to be the simplest way. The objectives of this work were to determine the contents of fourteen minerals in CPs and in insect species namely, house cricket, yellow mealworm, desert locust, and superworm. To assess these insect species as sources of minerals with respect to the dietary recommended values (DRV) for some minerals, and to determine mineral enrichment level of some recipes with using CP. Samples were analyzed by means of high-resolution continuum source graphite furnace atomic absorption spectrometry and flame atomic absorption/emission spectrometry. These insect species can be considered as a uniform source of Fe. The species of house cricket, yellow mealworm, and desert locust would provide more than the DRV for Zn, Cu, and P. Replacing 10 % of the wheat flour with CP in bread and pasta recipes increases Zn content by 92-107 %. Finally, the low Cd and Pb contents indicate that the consumption of the given insect species presents no risk.Masarykova Univerzita, MU: MUNI/A/1608/2020Masaryk University [MUNI/A/1608/2020
Chi-square of pseudorandom number generator of normal distribution in C++17
Get PDFHigh quality pseudorandom number generators were needed in many software solutions throughout the history of programming. Nowadays, these generators play an even more significant role in software development. Generally, these generatorsbring a certain level of coincidence in some algorithmswhich need it. This work focuses on the statisticalevaluation of one of the representatives of thegenerators using Pearson's Chi-square goodness of fittest. The generator of pseudorandom numbers undertest is the specific implementation in the modernstandard of the programming language of C++ (thestandard of C++17). Results presented in this paperinform whether the numbers generated by the selectedgenerator follow the desired probability distribution(normal) © 2021. Pavel Tomášek, Hana Tomášková & Jakub Rak; published by UIKTEN. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 Licenseproject of Applied informatics in population protection [RVO/FLKR/2020/04]; Department of Population Protection of Faculty of Logistics and Crisis Management at Tomas Bata University in Zli