Technology In Bratislava Research Articles

Testing the Efficiency of a Heat Pump with Radiant Systems in Heating Mode

The paper deals with the experimental testing of the efficiency of the operation of an air/water heat pump in connection with three radiant systems in heating mode in an office building, which is part of the central laboratories of the Slovak university of Technology in Bratislava. The testing was aimed at verifying the manufacturer's theoretical claims about efficiency of the heat pump based on the COP and SCOP values according to EN 14511-1:2022 and EN 14825:2022. The testing period was from 7 Jan. 2024 until 15 Jan. 2024. The aim of the testing measurements was to evaluate the calculated value of SPF efficiency for individual days and for the testing period. During the measuring period, the wall radiant system consumed 188 kWh, the ceiling system 216 kWh, and the floor radiant system 196 kWh. The heat pump consumed 227 kWh of electricity. The calculated SPF value was 2.64.

Thermal and Fast Neutron Measurement in the STU Mini Labyrinth Experiment

The Mini Labyrinth experiment is a neutron and gamma shielding experiment constructed at the Slovak University of Technology in Bratislava (STU). The STU Mini Labyrinth consists of NEUTRONSTOP shielding, blocks of moderators, various neutron sources, a graphite prism, and the detector handling robot. It was designed for research and education purposes, while several experiments are also available online or a hybrid form. There have been several versions of the Mini Labyrinth developed, while currently the V3 version is available. This paper presents the methodology to effectively perform thermal and fast neutron measurements using a PuBe neutron source. In the experiment presented in this paper also active and passive detectors were used, and moderator materials were investigated to slightly shift the neutron spectrum. As for active detectors, the SNM-11 boron coated corona detector was used. Among passive detectors the CR-39 track detectors were investigated. The measurements were carried out in two configurations and the results were evaluated by simulations using the SCALE6 system

A vision of a more sustainable Slovakia in the light of participatory processes

The paper reflects the results of the ongoing discussion about sustainable development in Slovakia as an increasingly urgent topic resonating across scientific disciplines. Specifically, it deals with the participation processes, which were realized in 2022-2023 under the auspices of the Ministry of Investments, Regional Development and Informatization of the Slovak Republic (MIRRI), and the second part of which was implemented at the Institute of Management of the Slovak University of Technology in Bratislava using its expert and organizational capacities. The mentioned activities follow the strategic document entitled Vision and Development Strategy of Slovakia 2030 and are related to the preparation of the document Vision and Development Strategy of the Slovak Republic until 2050 – Slovakia 2050. In the light of the outputs from the participation processes, the paper deals, among other things, with the necessity of accelerating the transformation of regional economies from the industrial towards the post-industrial society, including sustainable innovation-oriented circular economy less dependent on raw materials and energy, with the simultaneous optimization of the system of decision-making and effective management, based on partnership and division of responsibilities between different levels and various actors of sustainable development. It also points out that discussions about this vision have the potential to significantly frame the creation of concepts of integrated territorial innovation-oriented clusters, the urgency of which - in parallel with the frustration of the ineffectiveness of fragmented development processes and activities - is felt at different levels by practically all participating subjects of the professional discourse analyzed in this paper. The results of the participation process fully confirm that Slovakia is not adequately prepared to respond to the challenges associated with all the necessary transformation processes.

DESIGN THINKING FOR SPECIFIC PURPOSES: COMPARATIVE STUDY OF DESIGN THINKING TECHNIQUE TO ENHANCE EDUCATIONAL PROCESS FOR STUDENTS OF ENGLISH AND TEACHERS OF VARIOUS ACADEMIC FIELDS

Design thinking is a dynamic approach and mindset employed to explore innovative and creative solutions to a wide range of challenges. At its core, design thinking places significant emphasis on the individual, their emotions and needs. Professionals who embrace design thinking actively seek out issues that impact people and offer appropriate solutions that will benefit users. Consequently, design thinking is an ongoing and iterative process, continuously researching and enhancing a product or service to the user’s satisfaction. This study aims to compare how English language and culture in specialized communication students and university teachers of various academic disciplines at the University of Ss. Cyril and Methodius in Trnava and the Faculty of Materials Science and Technology at Trnava, Slovak University of Technology in Bratislava, Slovakia, perceive the application of design thinking in the educational process. Two workshops were conducted to explore the application of design thinking in American literature seminars, with a total of 45 students who took part in the survey. The third workshop focused on enhancing intercultural awareness through online seminars and searching for the most appropriate methods of teaching intercultural communication in the online space. The workshop had a total of 25 students, with 21 participating in the research. A pilot workshop for teachers was organized in May 2023 within the project titled “Support of internal systems for ensuring the quality of higher education at the University of Ss. Cyril and Methodius in Trnava, Slovakia”, with 25 university teachers participating (21 of whom took part in the survey). The research results indicate that both students and teachers perceive design thinking as a suitable method for the current educational process. Students identified presentation skills as their biggest challenge, whereas teachers did not face significant issues in this area due to their profession. Conversely, teachers expressed difficulties with digital skills, which were less prevalent among the students. Design thinking offers numerous benefits to students by creating a supportive learning environment. Additionally, for teachers, this method can become a part of their lifelong learning, as innovation relies on their motivation and efforts to teach traditional content differently.

Perspectives on the future of nuclear energy in Slovakia

AbstractThe Slovak electric power generation market is small compared to that of other European countries. Anyhow, quite a unique mix of energy sources, a small number of inhabitants, and a well-developed nuclear industry make the story of Slovakia interesting and worth knowing. The status of new builds and decommissioning activities is given with the following brief presentation of the Slovak University of Technology in Bratislava with a focus on the Institute of Nuclear and Physical Engineering. The last part of the contribution is devoted to the new platform for education in nuclear being established in Central Europe. European Nuclear Experimental Educational platform aiming to simplify access to research reactors and specialized laboratories for students and researchers is introduced and discussed.

Evaluation of a Measurement Turbulence Model of the Wind Pressure on the Ruin of a Fortified Tower

Abstract An analysis of the external pressure coefficient on the surface of a ruin in different flow directions is presented. The ruin has almost cube-like proportions with an open roof plane and a destroyed corner. Flow simulations were performed using 3D Time Steady RANS and compared with experimental results from the boundary layer wind tunnel at the Slovak University of Technology in Bratislava. The optimal turbulence model and internal mesh settings were selected based on their statistical evaluation. For an evaluation of the critical directions of the wind flow around the ruin, the values of the external wind pressure coefficient were obtained from the selected calculation model and settings.

Navigating the digital age: Exploring effective teaching and learning approaches for university students

The paper explores the effectiveness of traditional versus digital teaching and learning methods as perceived by university students. As digital technologies are fundamentally changing the ways of teaching, learning and teacher-student interaction, the impact of digitalization on students’ learning styles remains underresearched. The aim of the study is to determine to what extent teaching and learning methods need to be adapted to reflect the current needs of students in the digital era. An online questionnaire about evaluation of teaching and learning methods was used to collect data amongst students of Faculty of Electrical Engineering and Information Technology of the Slovak University of Technology in Bratislava. The conducted quantitative survey research and subsequent comparative analysis showed students’ preference for high hybridization of teaching and learning methods, i.e., blending of traditional and digital methods. In particular, the students require input that is primarily visual. The research also shows that the role of the teacher’s explanation continues to play a significant role in higher education.

Redefining the learning experience in design education at the Slovak University of Technology in Bratislava

Abstract The present paper offers the results and evaluation of quantitative research conducted during the years 2019 and 2020 among prospective graduates and alumni of the follow-up bachelor and master study programmes of Design at the Faculty of Architecture and Design of the Slovak University of Technology (FAD STU) in Bratislava, Slovakia. The presented results of the research, combined with an analysis of the local labour market data, study of literature and an evaluation of global design education trends, were used as the foundation for changes in the learning process in design education at FAD STU, first-time implemented in the existing study programmes in the academic year 2021/22. The paper aims to provide an explanation of the new approach to learning experience design within the bachelor and master study programmes as such, but mainly described on the example of Design Studio courses. At the time of publishing, the new approach was successfully implemented in one of the faculty’s vertical studios – MX lab – a learning platform focused on project-based learning and cooperation with partners in the automotive industry.

Peer Review Statement

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing Publishing.1. Type of peer review: Single anonymous2. Conference submission management system: Morressier3. Number of submissions received: 404. Number of submissions sent for review: 175. Number of submissions accepted: 166. Acceptance Rate (Submissions Accepted / Submissions Received × 100): 40.0 %7. Average number of reviews per paper: 2.358. Total number of reviewers involved: 359. Contact person for queries:Name: Mária BehúlováAffiliation: Slovak University of Technology in Bratislava, Faculty of Materials Science and Technology in Trnava, Jána Bottu 2781/25, 917 24 Trnava, Slovak RepublicEmail: maria.behulova@stuba.sk* means value has been edited

High-Fluence Multi-Energy Ion Irradiation for Testing of Materials.

Structural materials of the new generation of nuclear reactors, fission as well as fusion, must often cope with high production rates of transmutation helium. Their testing hence requires either a powerful source of fast neutrons or a high-fluence ion-irradiation facility providing sufficient amounts of high-energy helium to investigate its effect on the material. Most ion irradiation studies, however, concentrate on basic effects such as defect evolution or bubble swelling in narrow near-surface regions modified by ion bombardment. Studies on bulk samples with a relatively thick implanted region, which would enable, for instance, micromechanical testing, are underrepresented. This gap might be filled by high-fluence multi-energy ion irradiations modifying several tens of micrometres of the investigated substrate. High-energy ion accelerators providing reasonable currents with energies of tens of MeV are rarely employed in such studies due to their scarcity or considerable beamtime costs. To contribute to this field, this article reports a unique single-beam He implantation experiment aimed at obtaining quasi-uniform displacement damage across >60 μm with the He/dpa ratio roughly one order of magnitude above the typical spallation neutron target irradiation conditions. Some technical aspects of this irradiation experiment, along with recent developments and upgrades at the 6 MV Tandetron accelerator of the Slovak university of technology in Bratislava, are presented.

Simulation of urban storm-water runoff in storm-water management model

Abstract The research simulates the precipitation-runoff process in an urbanized area. The Slovak University of Technology in Bratislava, the Faculty of Civil Engineering, is chosen as the locality of interest. The construction of a mathematical model of the area of interest and the existing sewer network was used the storm-water management model software. The rain type was stimulated by the block type of rain and real precipitation events. The study results showed that some parts of the existing sewer network are overloaded already during a lower intensity rain event. Based on the results achieved in the future, it is considered with the proposal of measures for rainwater management.

Comparative study of LDA and PIV methods for flow homogeneity measurements

Abstract In the Hydraulic Laboratory of the Department of Hydraulic Engineering, Faculty of Civil Engineering, Slovak University of Technology in Bratislava the distribution of the flow velocity in a shaft intake structure was investigated on a physical model. The homogeneity of the flow velocity distribution in the intakes of turbines has a great influence on the turbine performance. Modern optical methods, particle image velocimetry and laser Doppler anemometry, were used to measure the flow velocity distribution in the model of the turbine intake. The particle image velocimetry method provides a record of the velocity field, while the laser Doppler anemometry method provides an accurate indication of the velocity at a given point. The flow velocity distributions in the examined profiles were measured by the particle image velocimetry and laser Doppler anemometry methods and the results were compared with each other.

RESPONSE OF PLASTIC TRACK DETECTOR OF THE TASTRAK TYPE TO NEUTRONS OF PU–BE SOURCE

The solid-state nuclear track detectors are widely used in a variety of nuclear physics experiments and radiation protection. The paper presents the first results of the newly acquired TASLImage™ neutron dosimetry system at the Slovak University of Technology in Bratislava. A comparison of experimental and calculated responses of a TASTRAK plastic nuclear track detector to neutron spectrum of Pu-Be source is presented. The ambient dose equivalents determined by the TASLImage™ system are compared with the ones measured by the NuDET-ENE neutron detector based on the use of ZnS(Ag) scintillator covered with a thin film of 6LiF thermal neutron converter accommodated inside the HDPE moderator. The first results are concluded, and further research needs are identified.

MEASUREMENT AND SIMULATION OF THE RADIATION DOSES AROUND THE 'MINI LABYRINTH' EXPERIMENTAL WORKPLACE AT STU.

One of the most effective ways of gaining user experience and minimizing user effects on modelling and simulation is benchmarking. Currently (2022) a new experimental workplace, the so called 'Mini Labyrinth' is being developed at Slovak University of Technology in Bratislava (STU). It is a simple neutron and gamma shielding benchmark, inspired by the ALARM-CF-AIR-LAB-001 ICSBEP experiment. The latest V2 setup consists of a PuBe neutron source, several NEUTRONSTOP C5 shielding blocks, H2O filled polylactic acid (PLA) tank, plastic source holder and detectors placed inside and outside the Mini Labyrinth. This paper is focused on the monitoring of the radiation doses around the workplace using the NuDET neutron detector and on the comparison of the measured quantities with ones simulated by SCALE 6 MONACO. The influence of the size of the model and the definition of the detector is studied in this analysis. The achieved results are presented and some discussions on further needed development are also included.

Study of the Allegro Core Performance

The presented paper is related to introduction of the design and neutronic characterization of the start-up core developed for Gas cooled Fast Reactor (GFR) demonstrator. Slovak University of Technology in Bratislava joined the project ALLEGRO in last decade within the consortium of middle-European institutions. In the development plan of the GEN IV GFR the ALLEGRO demonstrator is one of the most necessary steps. The ALLEGRO reactor is small helium cooled 75 MWth thermal power unit. Its main objective is to demonstrate the key GFR technologies and to perform tests of innovative materials. The reactor core is based on the standard and MOX pin type fuel in the first phase of the project. The active core of a large GFR 2400 makes use of ceramic materials, but in the first ALLEGRO core MOX fuel will be used. It will be mainly to demonstrate the viability of the technology and to acquire necessary experimental data for further research. In the presented works are identified the main discrepancies between ALLEGRO and GFR 2400 designs, the sensitivity analysis was performed for both reactors. Neutronic characterization is aimed to determination of the standard neutronic parameters using conventional computational systems. The results of sensitivity and uncertainty calculations are presented in conjunction with similarity analysis.

Lidar-Based Mobile Mapping System for an Indoor Environment

Abstract The article deals with developing and testing a low-cost measuring system for simultaneous localisation and mapping (SLAM) in an indoor environment. The measuring system consists of three orthogonally-placed 2D lidars, a robotic platform with two wheel speed sensors, and an inertial measuring unit (IMU). The paper describes the data processing model used for both the estimation of the trajectory of SLAM and the creation of a 3D model of the environment based on the estimated trajectory of the SLAM. The main problem of SLAM usage is the accumulation of errors caused by the imperfect transformation of two scans into each other. The data processing developed includes an automatic evaluation and correction of the slope of the lidar. Furthermore, during the calculation of the trajectory, a repeatedly traversed area is identified (loop closure), which enables the optimisation of the trajectory determined. The system was tested in the indoor environment of the Faculty of Civil Engineering of the Slovak University of Technology in Bratislava.

Case study from Slovak University of Technology, Bratislava

Abstract Analysis of the experimental results presented in the following chapter reveals experiences with introduction of active learning methods in basic mathematics courses at the Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava. Experiment was implemented in the academic year 2018/19, in basic courses Mathematics I and Mathematics II scheduled in the first year of bachelor study programs and in subject Basics of Statistical Analysis for bachelor students in the second year of their studies. The aim of the experiment was to find achieved level of knowledge acquisition and to compare abilities of students to solve mathematical problems individually or by collective work and collaboration in small groups. Anonymous questionnaire answered by students after completion of the experiment provided rich feedback and overview of their opinions, from which their attitudes towards different teaching methods applied in 3 compulsory subjects from their study programs could be deduced and summarised. Based on received data, research analysed also results that students achieved comparing their achievement from the secondary schools and in both maths courses at the university.

Impact of Turbulence Models of Wind Pressure on two Buildings with Atypical Cross-Sections

Abstract The article deals with the numerical analysis of the wind pressure distribution on a group of two high-rise buildings of different shape for different wind directions. The first building has the shape of a circular cylinder and the second was created by a combination of semicircles and a longitudinal member. The floor plan of the second building was similar to the letter S. The simulations were realized as 3D steady RANS. CFD results were compared with experimental measurements in the wind tunnel of the Slovak University of Technology in Bratislava. The results were processed using statistical methods such as correlation coefficient, fractional bias and fraction of data within a factor of 1.3, which determined the most suitable CFD model. The purpose of the present article was to verify the distribution of the external pressure coefficient on scale models at a scale of 1:350, which are located in the Atmospheric Surface Layer (ASL). In numerical modeling, the most important thing was to ensure similarity with the flow in the experimental Atmospheric Boundary Layer (ABL) and with the flow around the models. SST k–ω was evaluated as the most suitable turbulent model for the given type of problem. Turbulent models had a decisive influence on the overall distribution of external wind pressures on objects. The results showed that the most suitable orientation of the objects in terms of the external wind pressure coefficient is 0°, when the cylinder produced a shielding effect, with min mean cpe = −0.786. The most unfavorable wind effects were shown by the wind direction of 90° and 135° with the value min mean cpe = −1.361.

Combined Building-Energy Systems with Heat Transfer Control by Building Constructions using RES

Energy systems built into one of the building structures that serve to capture solar energy, geothermic energy, and ambient energy, or which have the function of end elements of heating, cooling, and ventilation system, we generally call combined building-energy systems. Among combined building-energy systems we include solar roofs with built-in pipe absorbers, building structures with active thermal protection (ATP) - active heat transfer control, which have a multifunctional purpose – a thermal barrier, low-temperature heating, high-temperature cooling, recuperation and accumulation of heat, solar and ambient energy collection, large-capacity heat storage (ground heat accumulators built simultaneously in the foundation slab of the building), or heat exchangers used for recuperative ventilation of buildings built into the foundation slabs and wall structures. The research of combined building-energy systems at the Department of Building Services, Faculty of Civil Engineering, Slovak University of Technology in Bratislava has been carried out continuously since 2005. Within five research projects (responsible researcher, Kalús, D.) HZ 04-309-05, HZ 04-310- 05, HZ 04-142-07 (research and experimental measurements took place in the years 2005 to 2007), HZ PG73/2011 (research and experimental measurements took place in the years 2011 to 2013), [13,] and HZ PR10/2015 (research and experimental measurements have been carried out since 2015), two experimental houses IDA I. and EB2020, a mobile laboratory designed for measuring and optimizing a compact heat station using renewable heat sources, were designed and built by the research team at our workplace, and also a research of a fragment of a perimeter wall with built-in active thermal protection was carried out in the climatic chamber of the Faculty of Civil Engineering STU in Bratislava, Slovak Republic. Significant contribution to the research was provided by doctoral students Ing. Martin Cvíčela, Ph.D., (supervisor, Kalús, D.), Ing. Peter Janik, PhD., (supervisor, Kalús, D.) and Ing. Martin Šimko, PhD., (supervisor, Kalús, D.), who described the results of the research in their dissertations. At present experimental measurements in the mobile laboratory are performed by doctoral student Ing. Matej Kubica, (supervisor, Kalús, D.). In the area of combined construction and energy systems, research and optimization of suitable solutions continues, which have been transformed into one European patent and three utility models.

Preface to the 26th International Slovak-Polish Scientific Conference on Machine, Modelling and Simulations (MMS 2021)

We are delighted to introduce you the publication of all reviewed papers which is the result of fruitful cooperation among the Technical University of Košice, University of Žilina, Alexander Dubček University of Trenčín, Slovak University of Technology in Bratislava, Kazimierz Wielki University in Bydgoszcz, Poznań University of Technology, Rzeszow University of Technology, Czestochowa University of Technology, Calisia University - Kalisz, Poland, AGH University of Science and Technology, Warsaw University of Technology, Regional technological institute, Jan Evangelista Purkyně University in Ústí nad Labem, Institute of Technology and Business in České Budějovice. The 26th International Slovak-Polish Scientific Conference on Machine Modelling and Simulations continues in the Slovak Republic and was held from 13th to 15th of September 2021 in Hotel Alexander, Bardejovské Kúpele, Slovak Republic. The international conference was established in 1996 and is held annually every year.List of Organizing Committee, Organizing Committee, Scientific Committee are available in this pdf.