rss_2.0Research Papers Faculty of Materials Science and Technology Slovak University of Technology FeedSciendo RSS Feed for Research Papers Faculty of Materials Science and Technology Slovak University of Technology Papers Faculty of Materials Science and Technology Slovak University of Technology 's Cover the Efficiency of a Robotic Cell Using Simulation<abstract> <title style='display:none'>Abstract</title> <p>The paper deals with the possibilities of increasing the efficiency of a robotic cell. The robot assembly station is a part of a multi-robotic workplace capable of performing solitary operations. The complete production cycle of the cell is subjected to a thorough analysis. Deficiencies, having a direct impact on cell efficiency, are identified. These shortcomings include redundant movements of the robotic arm, the absence of an inspection mechanism for the presence of assembly parts, and inefficient instructions of the production cycle algorithm. The identified deficiencies are eliminated using the CIROS simulation tool. The result of the adjustments is a global 11.4% increase in the efficiency of the robotic cell in terms of time performance.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Case Study of Building a Digital Twin for a Production System<abstract> <title style='display:none'>Abstract</title> <p>As the term of Industry 4.0 becomes more and more relevant with each passing day, it is up to researchers and companies to find solutions to integrating all the technologies it covers. One of those technologies, even though not highly developed, is simulation and building Cyber-Physical Systems for gathering data and improving the production processes. In the research described in this paper, we focused on integrating production data with simulation models in order to make the process of understanding and learning about complex production systems as simple and as quick as possible. This paper contains three sections. The first one introduces the theoretical fundamentals of our research. The second one focuses on the methods used to create a digital model of production system. The final one discusses the results of the conducted experiments, and their impact on further research.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Controlling a Small Mobile 3-Pi Robot Movement in a Maze Via the Neural Network Using Back-Propagation Learning Method<abstract> <title style='display:none'>Abstract</title> <p>The contribution is focused on technical implementation of controlling a small mobile 3Pi robot in a maze along a predefined guide line where the control of the acquired direction of the robot’s movement was provided by a neural network. The weights (memory) of the neuron were calculated using a feedforward neural network learning via the Back-propagation method. This article fastens on the paper by the title “Movement control of a small mobile 3-pi robot in a maze using artificial neural network”, where Hebbian learning was used for a single-layer neural network. The reflectance infra-red sensors performed as input sensors. The result of this research is the evaluation based on the experiments that served to compare different training sets with the learning methods when moving a mobile robot in a maze.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Application of Industrial Computer Tomography to Determine Wood Porosity<abstract> <title style='display:none'>Abstract</title> <p>The main objective of this research was to analyse the limitations of iCT - industrial computer tomography for measuring the wood pores characteristics as a new non-destructive method which is primarily intended to measure and inspect complete components primarily made of plastics or light metal. The subject matter of this paper are wood samples of paulownia (Paulownia tomentosa) and ash (Fraxinus excelsior) before and after thermal treatment. Porosity, pore volume and distribution of pores on the wood samples before and after the heat treatment were measured by iCT Metrotom 1500. The total porosity of the samples before thermal treatment was 5.28 % (paulownia) and 14.90 % (ash), while after thermal treatment, porosity increased to 9.50 % (paulownia) and to 30.78 % (ash). Changes in the porosity of the samples before and after heat treatment show an increase in porosity of 3.87 % (paulownia) and 15.88 % (ash).</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Analysis of Lifelong Learning in Industrial Enterprises in the Border Regions of the Slovak Republic and the Czech Republic<abstract> <title style='display:none'>Abstract</title> <p>Lifelong learning is a conscious learning process with the aim of acquiring knowledge, skills and competences throughout an individual’s life. For lifelong learning to be successful, learning activities must meet market requirements. Correct skills of employees and a serious approach to lifelong learning are now being viewed as essential meet the skills and workforce needs of the future. Well-adjusted education system improves quality of life and sense of self-esteem of employees, besides it brings benefits of competitiveness for the whole company. The key goal of the article was to identify the current needs of lifelong learning in industrial enterprises in technical fields. The conducted questionnaire survey was focused on the companies in the border regions of the Slovak Republic (the Trnava, Trenčín and Žilina regions) and the Czech Republic (the South Moravian, Zlín and Moravian-Silesian regions). The research was aimed primarily at the companies in the machinery and automotive industries. Based on the results of the questionnaire, the requirements for the training focused on technical areas such as: materials engineering, mechanical engineering, computer aided design and production preparation, automation and control of technological processes and mechatronic systems, production quality, IT security and others were defined.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Use of Blockchain Mechanisms in PLC Control and Safety Critical Processes<abstract> <title style='display:none'>Abstract</title> <p>In a few past years, a lot of cyber-attacks on industrial systems were accomplished. The main point of vulnerability of industrial control systems (ICS) is their connection to the Internet. Standard ICS rely on local solutions; however, with the revolution in the shape of Industry 4.0 concept, there are only a few industrial sectors with no connection to the global network. Some researchers have revealed critical vulnerability of the control systems. In this paper, we briefly summarize the current situation, and introduce our solution to the check of changes in PLC via other nodes in industrial network. The way how to do it is possible through using a checksum of actual code, and comparing with the checksums stored in other nodes.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Reliability Assessment of the Systems with Simple Interconnections<abstract> <title style='display:none'>Abstract</title> <p>The paper deals with determining the final value of simple systems reliability. Simple systems, the systems with simple interconnections, can be divided into a sequence of series and/or parallel subsystems. The paper presents the basic functional relationships used to assess the reliability of simple systems, however, they are also essential for understanding more complex systems. The paper graphically shows and analyzes the final reliability of the systems depending on the arrangement of subsystems, and also those depending on the number of subsystems.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00An Approach to Automated Programming of Industrial Robots Based on Graphic Data<abstract> <title style='display:none'>Abstract</title> <p>The article contains the design and implementation of a system for automatic program generation for an industrial robot, based on the graphical input recorded by camera. The content is divided into two parts. The first section deals with processing the visual data acquired from an external source to appropriate form, using edge identification and transformation from raster to vector image. The second part deals with the automatic program generation for industrial robot. The article describes different possible approaches to solution. The selected way of solution was implemented in real environment in a chosen programming language. The final section of the article presents the results of experiments, together with the overall evaluation of the results.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Virtual Control Object for Siemens Logic Controllers and Online PLC Education<abstract> <title style='display:none'>Abstract</title> <p>This paper deals with the possibility of creating virtual C # models connectable to a virtual PLC of Siemens. The models will lead to the improvement and simplification of the online PLC education. Hardware solutions cost a lot of money, while using a software version of PLC leads to cheaper simulations. Paper presents the design and implementation of the virtual models, including the ways of the interconnection with PLCSIM, visualization and finally demonstration for the selected virtual model.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00A Two Wheel Self-Balancing Vehicle<abstract> <title style='display:none'>Abstract</title> <p>This paper deals with the development of the equation of motion and practical implementation of low cost two-wheel self-balancing model of a Segway transporter. The experimental model of cart was designed and made under this study. Nonlinear equations of motion of real model and linearized model were derived. To develop the mathematical model, Matlab/Simulink was applied. The mechanical part was implemented into Simulink, and a DC motor was considered as a linear system. The real model was tested for its balance by implementation of a control algorithm consisting of a complementary filter and PID algorithm on an Arduino development board with peripheral devices. The fully functional self-balancing model was used as a demonstration in the teaching process of the Mechatronics courses.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Industry Communication Based on TCP/IP Protocol<abstract> <title style='display:none'>Abstract</title> <p>The design of control systems needs to ensure communication between multiple PLCs or external IoT devices. Furthermore, there are several ways of communication between them. This article dealt with the PLC communication based on TCP/IP protocol, and compared several communication options between two PLCs of the S7-300 and S7-1200 series connected using Profinet with a solution built in C# connected to the PLC via an OPC server. We used MODBUS TCP, TCON, and PUT/GET program blocks for comparison. We transmitted a digital Boolean data type and an analogue value of the integer data type via Profinet to read data from the S7-300 PLC and send data to the S7-1200. We compared the programming instructions standardly used as a client/server PLC programming with a Windows Forms application, and evaluated the advantages and disadvantages of this solution even when using external IoT devices. The solution was applied and successfully tested for communication between PLC S7-1200 and Nvidia Jetson Nano. We wrote program instructions for PLC in Siemens Tia Portal V15.</p> </abstract>ARTICLE2021-12-07T00:00:00.000+00:00Importance of Recycling the Waste-Cables Containing Copper and PVC<abstract> <title style='display:none'>Abstract</title> <p>Urbanization, development of economy, increasing population and improved living standards and lifestyle have caused a sharp growth in waste. Inappropriate or inefficient waste disposal techniques can cause serious air, soil, and groundwater pollution, which subsequently can negatively affect the urban environment and threaten the health of residents. The goal of waste management is to move to a circular economy in which waste does not exist. If there is no possible way to reduce or reuse waste, the best solution is recycling it. Recycling brings abundant benefits on the economic and ecological levels levels, and helps reduce overall human health risk of adverse impacts. Recycling of the waste-cables which contain PVC and copper replaces the production of virgin PVC and mining of copper from copper ore, it reduces landfill solid waste pressures, saves energy and water sources, reduces emissions to environment, and also reduces negative impacts from improperly dispose of waste, etc. This paper presents an overview of recycling techniques for the waste-cables containing copper as a core and polyvinyl chloride as an insulating layer or sheath. It also lists advantages and disadvantages of these techniques and importance of recycling this type of waste.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Fire Growth Rate Index as a Key Fire Characteristic of Electrical Cables<abstract> <title style='display:none'>Abstract</title> <p>This study deals with the Fire Growth Rate Index (FIGRA) as a key fire characteristic of electrical cables (determined by a cone calorimeter) that allows to estimate their reaction to fire class. Three power (supply) electrical cables (reaction to fire class B2<sub>ca</sub>) were tested by a cone calorimeter using different heat fluxes of 20, 30, 40 a 50 kW·m<sup>−2</sup>. The cables were three-wire (cross-section of each wire was 1.5 mm<sup>2</sup>) with a nominal voltage of 0.6 kV (alternating current), resp. 1 kV (direct current). The cable sheaths were made of an ethylene copolymer filled with aluminum hydroxide. The beddings were made of an ethylene copolymer filled with a mixture of aluminum hydroxide and calcium carbonate. The conductor insulations of one electrical cable were made of crosslinked polyethylene and the conductor insulations of the other two electrical cables were made of an ethylene copolymer filled with aluminum hydroxide. FIGRA was determined per unit length and unit area of electrical cables. FIGRA increased with increasing heat flux. At a heat flux of 50 kW·m<sup>−2</sup>, all the electric cables examined showed a very similar FIGRA (from 0.19 to 0.21 kW·m<sup>−1</sup>·s<sup>−1</sup> and 18.4 to 21.2 kW·m<sup>−1</sup>·s<sup>−1</sup>, respectively). Conversely, at a heat flux of 20 kW·m<sup>−2</sup>, the investigated cables showed greater FIGRA variance (in the range of 0.11 to 0.16 kW·m<sup>−1</sup>·s<sup>−1</sup> or 10.8 to 16.2 kW·m<sup>−1</sup>·s<sup>−1</sup>).</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Fire Characteristics of Polyethylene Dust<abstract> <title style='display:none'>Abstract</title> <p>Dust is a product or by-product in many industries. To ensure effective measures of explosion prevention, it is necessary to know the fire properties of dispersed and settled dust. These parameters cannot be calculated, but can be determined on the base of measurements in standard equipment. The article deals with the measurement of fire properties of polyethylene. The values of the minimum ignition temperature of settled and dispersed dust (MIT) and the values of explosion characteristics of polyethylene dust cloud lower explosion limit (LEL), maximum pressure P<sub>max</sub> and maximum rate of pressure rise (dp/dt)<sub>max</sub> were measured. The measurements were performed on the equipment according to the STN EN 80079-20-2: 2016 Standard Explosive atmospheres - Part 20-2: Material characteristics - Combustible dust test methods and according to the STN EN 14034 + A1: 2011 Standard Determination of explosion characteristics of dust clouds. The MIT of the settled dust was not determined (the sample melted), the MIT of the dispersed dust was 435 °C. The maximum explosion pressure P<sub>max</sub> reached 7.0 bar, and the maximum rate of pressure rise dP/dt was 37.5 bar.s<sup>−1</sup>.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Electrochemical Recovery of Silver Using a Simple Cell<abstract> <title style='display:none'>Abstract</title> <p>The amount of generated e-waste during the last decades has been steadily raising to the point at which it is highly desirable to obtain the precious metals by recycling the e-waste without the need of exploiting the environment. The rapid development of technology, steep growth of modern facilities with user-friendly electronical devices and a stiff competition between manufacturers are among the main reasons for decreasing the life span of such devices, and subsequently end up as an obsolete waste product. Rapid industrialization and urbanization have also caused many environmental problems, e.g. heavy metal contamination. Silver is one of the precious metals with exceptionally high industrial applications, which makes it an area of research of high interest. Demand for silver continues to grow with progress in the industrialized world, while the world reserves of high-quality silver ores are declining. Although, there are large stocks of low and lean quality silver ores still to be mined, the main goal of this article is to provide a simple, effective and eco-friendly method of silver recovery from e-waste, e.g. electrical circuit breakers using an electrochemical cell. After 20.75 days of the experiment, 1481.5 grams of silver contacts were processed with a final yield of 61.41 % grams of silver dendrite crystals (99.9 % purity).</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Determination of Timing Parameters of Dust Clouds Explosion in Dependence on the Size of the Vessel Volume<abstract> <title style='display:none'>Abstract</title> <p>EN 14034 standard defines the requirements for igniter, to determine the properties of dust clouds. The standard specifies the conditions for occurrence of explosions of dust clouds. According to the standard, equipment with a volume of 1m3 and 20L can be used to determine the explosion parameters of dispersed dusts. The equipment has the time parameters of dispersing and the ignition system defined in the Standard. Experimental determination of time parameters is required for a different chamber volume. The article therefore deals with the determination of parameters for dispersing system in the 291 litre chamber. Determination of igniter delay was performed on the base of setting the time relay. Activation of pressurised air flow was determined by calculation, and it was subsequently experimentally verified in laboratory conditions. A video camera recording was selected for measuring the rate of nitrocellulose ignition from the resistance wire. The result of this study is determination of the igniter timing in dependence of the explosion chamber volume. The time delay of the nitrocellulose igniter is 320 ms.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Initiation Parameters of Granulated Synthetic Polymers<abstract> <title style='display:none'>Abstract</title> <p>Polymeric materials, which are currently very often used in various industries, are often transported and stored in the form of granules before processing. This method has several advantages, but in most studies the test samples are modified to different shapes and dimensions. This paper is therefore focused on the initiation of selected granular plastics. Samples of five polymeric materials were exposed to an external heat flux from 20 kW.m<sup>−2</sup> to 40 kW.m<sup>−2</sup>. A spark initiator was used to ignite the released gaseous products of thermal decomposition of the polymer sample. FTP (flow-time product) method was applied to the obtained parameter - time to ignition, from which other initiation parameters were determined. The critical heat flux was determined in the range of 5.0 kW.m<sup>−2</sup> - 11.8 kW.m<sup>−2</sup>. Despite the relatively small thickness (4 mm), the samples behaved as thermally thick. During the measurement, thin surface layer melted, and the rest of the polymer remained in its original granulated form. Ignition temperatures were calculated according to the Stefan-Boltzmann’s law between 273 °C - 402 °C.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Utilization of Waste-Based Sorbents for Removal of Pharmaceuticals from Water: A Review<abstract> <title style='display:none'>Abstract</title> <p>Nowadays, the water contamination which is due to pharmaceuticals is increasing and alarming. The pharmaceuticals in water are very hazardous and toxic not only for the human life but also for environment. One of the promising methods of removing pharmaceuticals from the contaminated water is adsorption. Agricultural and industrial wastes or by-products can be used as low-cost adsorbents for pharmaceuticals removal. Low-cost adsorbents provide particular economic and environmental advantages. This paper presents an overview of utilizing of the waste-based adsorbents (mainly spent coffee grounds) for the removal of pharmaceuticals from water.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Preliminary Study Into the Decolorization of Selected Dyes By the Ozone Application<abstract> <title style='display:none'>Abstract</title> <p>Synthetic dyes widely used in many kinds of industry affect the colour of wastewater when released to environment due to insufficient treatment in typical sewage treatment plants. Only a small dose of those dyes may significantly affect colour of water and, according to the chemical composition, may pose risks to wildlife and humans. In the research described in this study, decolorization of three various dyes was investigated. Since colour removal of Congo Red such as Methylene blue using ozone have been reported by several authors, and the literature on Naphthol Green B is rather limited, in the present study we compare the decolorization rate of CR, MB and NGB. The colour removal occurred quickly and more than 90% of colour reduction was achieved within 3-6 minutes throughout all tested pH of the solution.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Potential Applications of Nanomaterials in Wastewater Treatment<abstract> <title style='display:none'>Abstract</title> <p>Over the last few decades, nanotechnologies have gained a great deal of attention, and various nanomaterials and techniques have been developed for water remediation. This study deals with the adsorption of Naphthol green B onto the magnetite nanoparticles synthetized by the coprecipitation method at the laboratory temperature. According to the obtained results, the sorption process is obvious only at the acidic condition when the pH of solution decreases to pH level 3. According to nonlinear fit of experimental data, the sorption of the Naphthol green B onto magnetite nanoparticles is assumed as multilayer, while the Freundlich model fits better (96.158 %) than the Langmuir model does (55.941 %).</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00en-us-1