Tomas Bata University in Zlín
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Synthesis and characterization of graphene oxide from residual biomass
No full textGraphene oxide (GO) is a member of the graphene family that is intensively used in many fields such as electronics, environmental protection, and biomedical applications. GO is mainly produced from commercially available graphite powder. In this study, however, GO was synthesized from alternative carbon-rich biomass residues that are readily available: spent tea leaves, and coffee waste. These residues were treated with dilute HCl to remove impurities and then soaked in NaOH to activate their carbon. Highly porous GO nanomaterials were successfully synthesized using the modified Hummer's method after pyrolysis of the biomasses at a moderate temperature. These nanomaterials were characterized using FTIR, Raman spectroscopy, SEM, and XRD. FTIR results indicated the removal of oxygen (C-O and O-H bonds), carboxyl, carbonyl, carboxylic, and epoxy functional groups from the biomass through pyrolysis. Raman spectroscopy of the GO particles revealed the extent of the oxidation process. SEM images showed vascular-shaped graphene layers with porous and semi-porous surfaces. X-ray diffraction patterns showed an amorphous shape. The properties of the synthesized GO particles were compared with GO produced from the conventional source: graphite. The results indicated considerable similarities. Hence, biomass residuals can be considered a viable, environmentally-friendly source for GO. © 2022 IEEE.Tomas Bata University in Zlin, TBU: IGA/CPS/2022/006; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: MSMT-44726/2013; Univerzita Tomáše Bati ve Zlín
Identification and assessment of occupational safety risks in case of failure to capture an orphan source of ionizing radiation
Get PDFOccupational safety and health belong to fundamental human rights. This fully applies to the protection of employees and other persons, which operate or are located in facilities for the collection of scrap metal. The founder of the landfill or the employer has an irreplaceable place in the field of protection of persons against the effects of ionizing radiation. Based on the identification and assessment of occupational safety risks in the event of failure to ensure timely detection of an orphan source of ionizing radiation, the operator must assess all risk factors with emphasis on radiation. At the same time, it must take specific regime measures, which would minimize the impact on people and the environment. The article deals with the causes of failure the system of protection against the effects of ionizing radiation. The assessment of these causes is performed using the fault tree analysis method with the application of Boolean equations. The result of solving the problem is the calculation of the failure of the regime protection system in the devices, intended for the collection of scrap metal, caused by human error as a result of intentional or negligent actions of the operator and insufficient training in the areas of control of measuring devices, principles of correct use of detection devices, insufficient visual identification of potentially dangerous objects. The contribution of this paper is in the design of appropriate regime measures eliminating the consequences of non-capturing a source of ionizing radiation. © 2022 Institut za Istrazivanja. All rights reserved.Technology Agency of the Czech Republic, TACR: VI04000080; Univerzita Tomáše Bati ve Zlíně: IGA/FLKŘ/2022/001, RVO/FLKŘ/2022/02, RVO/FLKŘ/2022/0
Увођење новог флексибилног система планирања људских ресурса засновано на дигиталном близаничком приступу: Студија случаја
No full textDigital twin technology has become one of the key directions of intelligent manufacturing with a strong relationship to product lifecycle management. It contributes to increasing efficiency and flexibility in solving highly complex problems in constantly changing conditions. However, many circumstances make the real implementation of effective scenarios generated by simulation software tools difficult. One of them are rigid working schedules that complicate flexible human resources planning in accordance with optimal production and logistics plans. This article aims to examine the role of the digital factory twin in advanced human resources planning. Using the case study method, a solution for better coordination of internal logistics processes and utilization of logistics staff based on discrete-event simulation is presented. Several scenarios were tested and results showed the inevitability of using flexible working schedules for maximum utilization of logistics staff. The purpose of this study is not only to show one special case of one company, but to emphasize the potential of these software tools to achieve long-term synergies in coordinating logistics, production and human resources management activities. As a result of this study, an extended physical-digital -physical loop model is presented. This extension consists in adding the second loop including communication with HR portal.RVO project; [VaV-IP-RO/2022/01
Quality cost flows in manufacturing companies
Get PDFCompanies have increasingly focused their attention on quality costs. Therefore, raising awareness of this group of expenses is essential. This paper aims to present a survey on the topic of costs of quality management in manufacturing companies in the Czech Republic. This paper opens with a literature review that focuses on the existing cost of quality models and then focuses on empirical research results. Manufacturing companies represent the framework of this research. The research with a total of 159 respondents provides information about the real market situation. The aim was to determine the significance of costs and cost-effectiveness. The study's findings revealed that 73% of organizations quantify their quality costs completely, 21% of companies quantify their costs only partly (external costs), and 6% of companies do not. 36% of surveyed companies (42 companies) that monitor quality costs use some of the recommended models, mainly the PAF model. The research was confirmed by hypothesis 1 that companies that use some type of evidence cost of quality have lower levels of these costs.Internal Grant Agency of FaME TBU; [IGA/FaME/2021/014
Biodegradable polyesters and low molecular weight polyethylene in soil: Interrelations of material properties, soil organic matter substances, and microbial community
Get PDFConventional and also biodegradable polymer microplastics have started to be broadly present in the environment, if they end up in soil, they may influence both abiotic and biotic soil properties. In this study, the interactions of polyethylene wax together with three biodegradable polyesters PLA, PHB and PBAT with a soil matrix were investigated over a 1-year incubation period. Soil organic matter content was measured using UV-VIS, the microbial biomass amount was measured using qPCR, the mineralisation of polymers was measured using UGA 3000, the surface of polymers was observed with SEM, live/dead microorganisms were determined by fluorescent microscopy and microbial consortia diversity was analyzed using NGS. The amount of humic substances was generally higher in incubations with slowly degrading polyesters, but the effect was temporary. The microbial biomass grew during the incubations; the addition of PHB enhanced fungal biomass whereas PE wax enhanced bacterial biomass. Fungal microbial consortia diversity was altered in incubations with PHB and PBAT. Interestingly, these two polyesters were also covered in biofilm, probably fungal. No such trend was observed in a metagenomic analysis of bacteria, although, bacterial biofilm was probably formed on the PE520 surface. Different methods confirmed the effect of certain polymers on the soil environment
Enhanced specific capacity and cycling stability of flexible nanocellulose-based pseudocapacitive electrodes by controlled nanostructuring of polyaniline
Get PDFFlexible, lightweight and electrically conductive composites based on renewable resources have recently attracted a growing interest for the development of high performance sustainable energy storage devices that can meet the needs of modern wearable and portable electronics. Herein, we developed a high performance carbon black@polyaniline (PANI) based flexible electrodes using a facile, low cost and environmentally friendly strategy. The strategy consisted of a co-deposition and nanostructuring of PANI layer with tailored morphology on the surface of carbon black and nanofibrillated cellulose (NFC) via in situ polymerization. NFC acted as a mechanical skeleton and imparted the electrode with strength and flexibility to ensure excellent electrochemical performance. The co-doping of PANI chains via a combination of a primary/secondary dopant, namely, HCl/poly(2acrylamido-2-methyl-1-propanesulfonic acid), was used to control the morphology of PANI. Correlation between the textural properties of the carbon black, NFC loading, and the properties of the resulting electrodes was established. The maximum specific capacitance of 363 +/- 9 F/g at the potential scan rate of 50 mV/s was exhibited by the electrode with 60% of active material loading, for which an effective growth of hierarchical nano structures of carbon black@PANI on the surface of NFC was achieved, leading to the highest specific surface area of the composite (861 m2/g) and a to a microporosity/mesoporosity balance. The remarkable cycling stability of the hybrid electrodes was attained as the specific capacitance retention was close to 100% with a negligible capacity decay within the tested period (over 500 cycles) regardless of the amount of the active material. This study provides an eco-friendly and cost-effective way to prepare high performance flexible electrodes for pseudo capacitorsGrantová Agentura České Republiky, GA ČR: GAČR No. 21–09830SCzech Science Foundation (GACR) [21-09830S]; Specific University Research [A2_FCHI_2022_007
Constructing a cryptocurrency-price prediction model using deep learning
No full textThe purpose of this study is to discover the optimal Deep Learning model for Bitcoin prediction among the Convolutional Neural Network (CNN), Recurrent Neural Network (RNN), and Long Short-Term Memory (LSTM). Our empirical results indicate that LSTM is the optimal model for predicting Bitcoin price and trend with the prediction accuracy of 88.9%. Our study serves as a stepping stone for novice cryptocurrency investors and future studies of more advanced and sophisticated algorithms. Finally, given that the ideal model for predicting the price of cryptocurrencies is still a topic of controversy, the findings of this study will serve as a valuable empirical resource for future studies. © 2022 IEEE
Analysis of damage origin of bevel gear wheels
Get PDFThe safety and smooth operation of manufacturing facilities also depends on ensuring the failure-free operation of technical equipment. Power transmission failures in particular are usually the cause of shutdown of the entire manufacturing facility. The characterization of gear failures ac-cording to their origin plays an important role in determining safe operating conditions. The presented paper is dedicated to the problem of damage of specific gears, defining the extent of damage, determining the possible causes of damage. The problem is solved for a single-stage helical bevel gearbox with, which is a part of the mechanism of a small hydroelectric power plant. The aim is to determine the conditions for proper operation, based on the evaluation of the extent of damage to this gearbox, so that the gearbox is no longer damaged to such a large extent.Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGA: 005TUKE-4/2022, 018TUKE-4/2022, 029TUKE-4/2021, APVV-21-0195, IGA/FLKŘ/2022/001, RVO/FLKŘ/2022/03VEGA [1/0101/22, 1/0600/20]; KEGA [005TUKE-4/2022, 018TUKE-4/2022, 029TUKE-4/2021]; [APVV-21-0195]; [IGA/FLKR/2022/001]; [RVO/FLKR/2022/03
Antibacterial thin films deposited from propane-butane mixture in atmospheric pressure discharge
Get PDFAntibacterial coatings on biomedical instruments are of great interest because they can suppress bacterial colonization on these instruments. In this study, antibacterial polymeric thin coatings were deposited on teflon substrates using atmospheric pressure plasma polymerization from a propane-butane mixture. The plasma polymerization was performed by means of surface dielectric barrier discharge burning in nitrogen at atmospheric pressure. The chemical composition of plasma polymerized propane-butane films was studied by energy-dispersive X-ray spectroscopy (EDX) and FTIR. The film surface properties were studied by SEM and by surface energy measurement. The EDX analysis showed that the films consisted of carbon, nitrogen and oxygen from ambient air. The FTIR analysis confirmed, in particular, the presence of alkyl, nitrile, acetylene, imide and amine groups. The deposited films were hydrophilic with a water contact angle in the range of 13-23 degrees. The thin film deposited samples were highly active against both S. aureus and E. coli strains in general. On the other hand, the films were cytocompatible, reaching more than 80% of the cell viability threshold compared to reference polystyrene tissue.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2022/001, RP/CPS/2022/002; Ministerstvo Obrany České Republiky, MOČRMinistry of Defence of the Czech Republic; Ministry of Education, Youth and Sports of the Czech Republic [RP/CPS/2022/001, RP/CPS/2022/002
Distance learning of geographic information systems using Google Classroom: Students' assessment and perception
Get PDFDistance education at universities during the COVID-19 pandemic was implemented through various so-called learning management systems (LMSs). These environments are primarily used for teacher–student communication, assignment, and sharing of learning materials, testing, and assessment. This article aims to evaluate the Google Classroom environment’s perception by university students of the courses Teaching Academic Subjects and Geography, forced to study through distance learning during the second half of the semester. Students filled out a questionnaire focused on the perception and evaluation of the Google Classroom environment at the end of the semester. The students were divided into two groups, depending on whether they worked in the Google Classroom environment for the first time or not. The results were evaluated using the Wilcoxon rank-sum test and the semantic differential method. The results show students’ positive attitudes toward this environment, even though some were working with it for the first time. The perception and identification of the strengths and weaknesses of learning environments are essential in their future use in creating curricula and analysis of possible further use in other subjects or situations. © 2022 by American Association of Geographers