Tomas Bata University in Zlín
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The polymorphic composition of long-chain branched polypropylene processed by injection and compression molding
Get PDFThe impact of injection molding processing parameters, including mold temperature, injection speed, and holding pressure, on the supermolecular structure of long-chain branched polypropylene (LCB-PP) was investigated. Commercial LCB-PP was processed under different conditions, with four sets of processing parameters applied. Holding pressure was varied from 30–70 MPa by 10 MPa in the P-SET, mold temperature was raised from 40 to 120 °C in 20 °C steps in the T-SET, and injection speed increased from 20 to 140 mm/s in 30 mm/s steps in S-SET1 and S-SET2, with mold temperatures at 40 or 120 °C. The polymorphic composition of the specimens was analyzed using wide-angle X-ray scattering, demonstrating a strong dependence on the processing parameters. The skin of the specimens showed an increase in β-phase content with higher mold temperature and injection speed. Conversely, growing holding pressure slightly suppressed β-phase content and promoted the formation of the γ-phase, which was predominantly manifested in the core of the specimens. The polymorphic composition, with both β-and γ-phases present in notable amounts, had a beneficial effect on the impact strength of the specimens
Maximizing efficiency: A comparative study of SOMA variants and constraint handling methods for time delay system optimization
No full textThis paper presents an experimental study that compares four adaptive variants of the self-organizing migrating algorithm (SOMA). Each variant uses three different constraint handling methods for the optimization of a time delay system model. The paper emphasizes the importance of metaheuristic algorithms in control engineering for time-delayed systems to develop more effective and efficient control strategies and precise model identifications. The study includes a detailed description of the selected variants of the SOMA and the adaptive mechanisms used. A complex workflow of experiments is described, and the results and discussion are presented. The experimental results highlight the effectiveness of the SOMA variants with specific constraint handling methods for time delay system optimization. Overall, this study contributes to the understanding of the challenges and advantages of using metaheuristic algorithms in control engineering for time delay systems. The results provide valuable insights into the performance of the SOMA variants and can help guide the selection of appropriate constraint handling methods and the adaptive mechanisms of metaheuristics.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); Narodowe Centrum Nauki, NCN, (2020/39/I/ST7/02285); Ministerstwo Edukacji i Nauki, MNiSWNCN, Polish Ministry of Education and Science [2020/39/I/ST7/02285]; Czech Science Foundation (GACR) [GF21-45465L]; Internal Grant Agency of the Tomas Bata University in Zlin [IGA/CebiaTech/2023/004
Operating point shift induced by relay asymmetry: An iterative solution proposal
No full textThis contribution focuses on a problem that appears when using a relay with non-symmetric output in the closed loop. Such a scheme is usually used for process model parameters identification, possibly followed by automatic controller tuning. Whenever static or dynamic properties of the process reveal asymmetry when the sign of the input changes, the setpoint (reference) becomes different from the operating point value of the process output. As a class of relay-based identification methods utilize calculations in the frequency domain that are based on integral computation around the operating point, the discrepancy between the setpoint and the operating point can lead to incorrect results. The aim of the paper is mainly to provide the reader with problem formulation and step-by-step proposition of how it can be solved. Concise numerical examples are also given. The concluding remarks suggest possible further ways of research.Grantová Agentura České Republiky, GA ČR, (GAČR 21-45465L); Narodowe Centrum Nauki, NCN, (2020/39/I/ST7/02285)Czech Science Foundation; GACR [21-45465L]; National Science Centre Poland [2020/39/I/ST7/02285
Shifts in the smart research agenda? 100 priority questions to accelerate sustainable energy futures
Get PDFEnergy transitions are at the top of global agendas in response to the growing challenges of climate change and international conflict, with the EU positioning itself as playing a pivotal role in addressing climate risks and sustainability imperatives. European energy transition policies identify 'smart consumption' as a key element of these efforts, which have previously been explored from a predominantly technical perspective thus often failing to identify or address fundamental interlinkages with social systems and consequences. This paper aims to contribute to interdisciplinary energy research by analysing a forward looking 'Horizon Scan' research agenda for smart consumption, driven by the Social Sciences and Humanities (SSH). Reflecting on an extensive systematic Delphi Method exercise surveying over 70 SSH scholars from various institutional settings across Europe, we highlight what SSH scholars see as future directions for smart consumption research. Building from seven thematic areas (under which are grouped 100 SSH research questions), the study identifies three key 'shifts' this new smart research agenda represents, when compared to previous agendas: (1) From technological inevitability to political choice, highlighting the need for a wider political critique, with the potential to open up discussions of the instrumentalisation of smart research; (2) From narrow representation to diverse inclusion, moving beyond the shortcomings of current discourses for engaging marginalised communities; and (3) From individual consumers to interconnected citizens, reframing smart consumption to offer a broader model of social change and governance. Social Sciences and Humanities scholarship is essential to address these shifts in meaningful (rather than tokenistic) ways. This agenda and the shifts it embodies represent key tools to enable better interdisciplinary working between SSH and teams from the technical and natural sciences.Ministry of Education, Youth and Sports of the Czech Republic DKRVO, (RP/CPS/2022/005); Horizon 2020 Framework Programme, H2020; European Commission, EC; Horizon 2020, (826025)European Union [826025]; Ministry of Education, Youth and Sports of the Czech Republic DKRVO [RP/CPS/2022/005
Innovation of the production process of coin dies to increase their service life
Get PDFThe article deals with the problem related to the service life of the coin dies. The faultless condition of tools during the long-time process of the production of the coins is a basement for their quality. It is influenced by several aspects. The most important factors can be considered the material of the coin die - especially its purity, relief production technology, heat treatment - especially the correct observance to procedures and the choice of equipment, achieved mechanical properties, method of final relief treatment - e.g., coating and the existence of residual stresses in the tool. The aim of the present research was to examine the cause of the failure and damage of the coin dies after production of a small number of coins and, accordingly, to make changes in the production process to prolong their service life. By monitoring the individual steps of the production process, it was possible to identify specific causes of premature decommissioning of coin dies. Innovations have been made at each step of the production process to extend the life of the coin. The paper presents the modifications in the heat treatment of the coin dies as one of the basic improvements in their no-failure long time operation. This, together with other identified shortcomings in the tool manufacturing process, has contributed to an increase in the number of coins minted from around 6,000 to 740,000 coins.Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky, (APVV-19-0550); Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGA, (005TUKE-4/2021
Effect of crosshead speed and volume ratio on compressive mechanical properties of mono- and double-gyroid structures made of Inconel 718
Get PDFThe current development of additive technologies brings not only new possibilities but also new challenges. One of them is the use of regular cellular materials in various components and constructions so that they fully utilize the potential of porous structures and their advantages related to weight reduction and material-saving while maintaining the required safety and operational reliability of devices containing such components. It is therefore very important to know the properties of such materials and their behavior under different types of loads. The article deals with the investigation of the mechanical properties of porous structures made by the Direct Metal Laser Sintering (DMLS) of Inconel 718. Two types of basic cell topology, mono-structure Gyroid (G) and double-structure Gyroid + Gyroid (GG), with material volume ratios of 10, 15 and 20 %, were studied within our research to compare their properties under quasi-static compressive loading. The testing procedure was performed at ambient temperature with a servo-hydraulic testing machine at three different crosshead testing speeds. The recorded data were processed, while the stress–strain curves were plotted, and Young’s modulus, the yield strength Re0.2, and the stress at the first peak of the local maximum σLocMax were identified. The results showed the best behavior under compression load among the studied structures displayed by mono-structure Gyroid at 10 %. At the same time, it can be concluded that the wall thickness of the structure plays an important role in the compressive properties but on the other hand, crosshead speed doesn´t influence results significantly.Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky, (APVV-19-0550); Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGA, (005TUKE-4/2021, 032TUKE-4/2022, SK-CN-21-0046)ELKEME S.A [APVV-19-0550, KEGA 005TUKE-4/2021, KEGA 032TUKE-4/2022
Effective parametric optimization of heating-cooling process with optimum near the domain border
No full textHeating-cooling processes are widely used in industry and are often subject to latencies and delays. Although the parameters of such processes can be identified using mathematical and physical modeling, this technique is highly demanding both when it comes to the amount of a priori knowledge required and the time it takes to find a solution. In this work, we provide a robust formulation of a time-delay control problem and propose a numerical approach to finding its parameters in a form of an optimization task. Consequently, we apply various techniques and metaheuristics to obtain a high quality solution and discuss key observations made in the process. © 2022 IEEE.978-1-6654-5656-2/22; Grantová Agentura České Republiky, GA ČR: GF21-45465L; Narodowe Centrum Nauki, NCN: /35/O/ST6/00570, 2020/39/I/ST7/02285; Ministerstwo Edukacji i Nauki, MNiS
The role of lie detection based system in controlling borders
No full textSecurity engineering refers to the latest techniques and methods used to protect large numbers of people concentrated in public crowded places every day. Such a new modern method represents the Intelligent Portable Border Control System (iBorderCtrl) based on lie detection. This paper describes and analyses this automated deception detection border security system developed mainly for airport security but also for the control of the land border crossing points as roads, walkways, or train stations. The system is built using advanced and high-performance deep learning models with the aim of effectively prevent any threats or potentially dangerous situations from arising or entering the country. © 2021 Danube Adria Association for Automation and Manufacturing, DAAAM. All rights reserved.IGA/CebiaTech/2021/00
The 3D scanning image quality of the interior with the mirror surface
No full textThis article deals with the theory of digital image transmission. Image quality and possible deterioration when scanning the interior using a 3D scanner. Noise in white areas has reduced image quality. Brightness and contrast values have been changed to increase quality. This adjustment suppressed noise, but not significantly. The mirror placed in the interior created a secondary 3D model and point clouds of the scanned space. The occlusion of point clouds from both 3D models could significantly increase image quality, especially in detail. © 2020 Danube Adria Association for Automation and Manufacturing, DAAAM. All rights reserved.IGA/CebiaTech/2020/003; Univerzita Tomáše Bati ve Zlín
Motors driving unit for a small airship
No full textIn the framework of desinging an Autonomous Monitoring System at Tomas Bata University in Zlin we solved a problem of driving dc motors for RC models by a microcontroller. For this purpose we made a testing kit employing an L298 double full-bridge driver. In this article we would like to describe the design of this kit as it was found suitable for driving motors of a small airship. In the future this circuit will be integrated into a complex driving board