Acta Mechanica Slovaca - Latest articles
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Laws of Particle Entrainment from Fluidized Bed Apparatuses
Mykola Yukhymenko, Ruslan Ostroha, Denys Ostroha, Yakov Mikhajlovskiy
Acta Mechanica Slovaca 2024, 28(3):18-24 | DOI: 10.21496/ams.2024.024 
The article presents the results of experimental studies of the process of entrainment of particles of fine fractions from the fluidized bed of polydisperse mixture of granular superphosphate. A review of the main analytical dependencies for determining the amount of entrainment from the fluidized bed is presented. The results of experimental studies of the entrainment process from the fluidized bed of small particles with a size less than 1 mm and large particles with a size more than 1 mm in the interval of gas flow velocities 0.5 - 5.0 m/s are given. The results of calculating the value of fine fraction entrainment from the fluidized bed of superphosphate...
Crankshaft Bearing Hydrodynamic Lubrication Study in an Internal Combustion Engine (under variable dynamic loading)
Abdelmadjid Said, Abdelhamid Bounif, Patrick Maspeyrot
Acta Mechanica Slovaca 2024, 28(3):6-17 | DOI: 10.21496/ams.2024.023
The engine crankshaft bearing is an important component and vulnerable part of engine. Its operating condition significantly influences the dynamic performance, efficiency and overall reliability of the engine. In modern engine design, the main objective is to improve power output while minimizing friction losses and reducing fuel consumption. This present work concerns the study of the behavior in dynamic mode of the big-end and small-end bearings of connecting rod in internal combustion engine, taking into account the rupture and reformation of the fluid film in the contact region in the inactive cavitation zone. The most important operating parameters...
Angled G-Code Generator for Robotics Additive Manufacturing
Pavol Štefčák, Ivan Gajdoš, Ján Slota, Lukasz Sobaszek
Acta Mechanica Slovaca 2024, 28(2):76-82 | DOI: 10.21496/ams.2024.022
The current state of the utilization of robotic arms in large-scale additive manufacturing (AM) has spurred the development of new hardware and software solutions stemming from the need to reduce the cost of preprocessing and production itself. The use of 6 degrees of freedom combined with the proper software solution for generating the machine motion paths can largely save the time and material required for production of the large-format products. Although several studies have been carried out in this area outlining the possibilities of generating non-planar layers exploiting the potential of 4 or more degrees of freedom all these studies have been...
Three-dimensional Bioprinting with the Use of Induced Pluripotent Stem Cells in Regenerative Medicine
Jana Demeterová, Marianna Trebuňová, Darina Bačenková
Acta Mechanica Slovaca 2024, 28(2):68-74 | DOI: 10.21496/ams.2024.019
The field of regenerative medicine has witnessed significant advancements in recent years due to the emergence of three-dimensional (3D) bioprinting technology. One promising approach is the utilization of induced pluripotent stem cells (iPSCs) as a cell source for bioprinting, allowing for the construction of complex tissue structures. iPSCs hold immense potential as they can be derived from a patient's own cells, enabling personalized therapies, and eliminating the risk of immune rejection. The integration of iPSCs with 3D bioprinting technology expands the possibilities of regenerating damaged tissues and organs. iPSCs can be programmed to differentiate...
Analysis of the Relationship Between the Motion Resistive Force and the Road Surface for Special Purpose Off-Road Vehicle
Marek Nowakowski, Przemyslaw Siminski, Krzysztof Kosiuczenko
Acta Mechanica Slovaca 2024, 28(2):62-66 | DOI: 10.21496/ams.2024.010
A comprehensive understanding of the relationship between motion resistive force and road surface is essential for operation of special purpose off-road vehicles. This research focuses on the testing of a developed Light Terrain Vehicle (LST). Design of LST special vehicle as well as used equipment for testing purposed is descried. The paper presents carried out testes on typical road surfaces closely related to the operational conditions. The study enables defining operational usage of developed special purpose off-road vehicle in diverse environments.
Conceptual Design of a Bioreactor for Tissue Engineering and Regenerative Medicine
Petra Kolembusová, Norbet Ferenčík, Radovan Hudák
Acta Mechanica Slovaca 2024, 28(2):52-60 | DOI: 10.21496/ams.2024.030
The aim of the paper was to make an overview of current bioreactor systems in tissue engineering and introduces a conceptual design for a perfusion bioreactor tailored for vascular tissue culture. Perfusion bioreactors were selected for their ability to replicate the in vivo environment, particularly for blood vessels, by providing continuous media flow and applying shear stress, both critical for successful vascular tissue growth. Three bioreactor variants were designed, each incorporating specific modifications aimed at improving the tissue culture process. Variant A consists of a cylindrical chamber that allows for uniform external media flow. Variant...
Metamaterials and Their Application in Biomedical Engineering
Barbara Schürger, Peter Frankovský, Ingrid Delyová, Jozef Živčák, Sára Janigová
Acta Mechanica Slovaca 2024, 28(2):44-50 | DOI: 10.21496/ams.2024.016
Mechanical metamaterials have attracted attention due to their unique mechanical properties, such as low weight, adjustable stiffness, and auxeticity, making them excellent candidates for biomedical engineering innovative applications such as bone implants, vascular stents, and other healthcare applications. In this review, we will focus on the mechanical properties and behavior of these materials under different conditions, focusing on their application in the field of biomedical engineering.
Modelling of Pulsed Flow Effects Through the Exhaust System of a Turbocharged Engine Using Mixed Flow Turbine
Djamel Mazari, Mustapha Bordjane, Mohammed Hamel, Khadidja Boualem
Acta Mechanica Slovaca 2024, 28(2):28-43 | DOI: 10.21496/ams.2024.007
For some decades, reductions of fuel consumption and pollutant emission control have become the first requirement for internal combustion engines. Turbocharging is a promising way among many techniques to solve this problem since it leads to a downsized, lighter and more compact engine. Two important novelties can be listed in this study, the first is the development of a thermodynamic (zero dimensional) model for the gas expansion process through the exhaust system of turbocharged internal combustion engines. The latter is used to setup the unsteady state analysis using interpolation function for cyclic time of the internal combustion engine and the...
Impact of Casting Speed on Low Carbon Steel Manufacturing Process
Luboš Polcar, Marek Velička, Jan Růžička, Arasappan Yesudass
Acta Mechanica Slovaca 2024, 28(2):22-27 | DOI: 10.21496/ams.2024.013
Presented paper is focused on research of low carbon steel behaviour during continuous casting process. Research was conducted to investigate optimization opportunity of current casting process and possibility of increase in casting speed. Research was focused mainly on primary cooling area which is represented by mould. Mould insert was drilled, and thermocouples were installed in centreline of each side. Among others also temperatures and flow of cooling water, mould insert temperature and surface temperature of billet on the exit from the mould were measured. From conducted research it can be concluded that all following values exhibit strong linear...
A Numerical Study of the Innovative Design of Kinetic Static Mixer on Mixing Efficiency and Heat Transfer Improvement
Ourdia Benabdellaziz, Youcef Kamla, Ahmed Mouissi, Abdelkader Karas, Zied Driss
Acta Mechanica Slovaca 2024, 28(2):6-20 | DOI: 10.21496/ams.2024.008
This paper investigates the influence of rheological and geometrical properties on flow structures generated within a KENIC static mixer. The primary objectives are to examine the impact of these factors on fluid flow characteristics, particularly low-pressure conditions and mixing efficiency. To exanimate the performances of the different shapes, several parameters have been considered which consist on mixing index, thermal mixing index, hydrodynamic behavior and the probability density function. The investigation extends to encompass both Newtonian and non-Newtonian fluids, emphasizing Reynolds numbers ranging from 10 to 80. Comparative analyses...
Analysis of the Mixing of a Newtonian Material with a Strongly Viscous Material using CFD Numerical Modelling
Jan Adamec, Marian Bojko, Rostislav Zapletal, Josef Veselý
Acta Mechanica Slovaca 2024, 28(1):60-65 | DOI: 10.21496/ams.2024.002
This article deals with the mixing of a Newtonian material with a strongly viscous (non-Newtonian) material in a pipe with a static mixer. This problematic has a practical application in the food industry. CFD software ANSYS Fluent was used for numerical modeling. The mathematical model is defined using the basic balance equations, including the equation for species. The viscosity for a non-Newtonian highly viscous material (the working material) is defined using the Herschel-Bulkley model. A 3D computational model of a pipe with a static helical mixer is created in the DesignModeler program, which is part of the ANSYS software. The computational mesh...
Absorption Potential of Modern Steels when used for the Car-body Evaluated by the 3-point Bending Test with Stretching
Marek Buber, Emil Evin, Miroslav Tomáš
Acta Mechanica Slovaca 2024, 28(1):52-59 | DOI: 10.21496/ams.2024.015
Beside the active safety components of the car, the passive safety elements incorporated in the car-body structure are important too. To ensure passenger safety during a car accident, advanced materials are used in deformation zones. The article deals with testing the material's absorption ability by a 3-point bending test with stretching. The test allows simulating material behaviour during bending load when combined with stretching and determining the properties of the metal sheets, such as the absorption potential of the material and stiffness constant. The purpose of this article is to evaluate the innovation potential of the dual-phase steel HCT600X...
Unlocking Industry Potential: The Evolution and Impact of Digital Twins
Laura Lachvajderová, Martin Trebuňa, Jaroslava Kádárová
Acta Mechanica Slovaca 2024, 28(1):46-51 | DOI: 10.21496/ams.2024.009
Digital twins have emerged as integral components of modern industrial operations, owing to their ability to create virtual replicas of physical assets, processes, or systems. This article thoroughly explores the manifold applications of digital twins within the industry, emphasizing their role in enabling data-driven decision-making. These virtual counterparts facilitate real-time monitoring, analysis, and optimization, thereby enhancing operational efficiency. Additionally, they play a crucial role in predictive maintenance by minimizing downtime and prolonging the lifespan of machinery. By expediting testing and simulation procedures, digital twins...
Evaluation and Comparison of the Mechanical Behaviors of a Middle Ear Prosthesis using the Finite Element Method
Fekih Sidi Mohamed, Khatir Omar, Sahli Abderahmene, Boudjemaa Ismail, Benkhettou Abdelkader
Acta Mechanica Slovaca 2024, 28(1):38-44 | DOI: 10.21496/ams.2024.006
Advancements in audiology and medical engineering have generated growing interest in enhancing titanium implants for middle ear restoration. In our study, we employed a finite element model of the middle ear to assess the behavior of the TORP prosthesis and the stapes under an acoustic pressure of 90 dB across a frequency range of 250 to 8000 Hz. The results were compared to experimental measurements obtained using a Doppler-effect-based laser vibrometer while varying the materials of the prosthesis to evaluate their mechanical impact. A satisfactory correlation between the simulation and experimental measurements validated our model.
Comprehensive Investigation of Solar Water Heater System Performance, Stratification, Charging, and Discharging Efficiency Using TRNSYS Software
Hanane Berrebah, Touhami Baki, Mohamed Tebbal
Acta Mechanica Slovaca 2024, 28(1):26-36 | DOI: 10.21496/ams.2024.005
A study by dynamic simulation using the TRNSYS software was carried out to visualize the performance of a solar water heater with forced circulation for one year. Thermal needs in domestic hot water for an average family of six people living in the city of Oran in Algeria are covered by solar energy by up to 63%. Parameters such as the angle of inclination, the surface of the solar panel, the storage volume, the heat exchanger's surface, and the flow rate of the solar loop have been optimized. An analysis of the temperature stratification inside the balloon was presented, along with the calculation of charging and discharging efficiency. The influence...
Temperature Measurement of NiTinol Spring without Physical Contact
Jaroslav Romančík, Ondrej Majerčák, Marek Vagaš
Acta Mechanica Slovaca 2024, 28(1):22-25 | DOI: 10.21496/ams.2024.003
Currently, scientists from various fields are trying to find new ways of activating devices, considering the renewability of the used resources. The way to this goal can also be the search for the usability of various advanced materials in hitherto unexplored areas of technology. This article delves into the application of a non-contact infrared sensor MLX90614 to track dynamic temperature changes in a nitinol spring. By utilizing a controllable external power source, the material's temperature is manipulated through current modulation. This fluctuation is then captured and logged by a system that includes a microcontroller and a temperature sensor....
Impact of Psychological Stress on the Development of Musculoskeletal Diseases
Denisa Porubčanová, Michaela Balážiková, Peter Darvaši, Lukáš Ďuriš, Ivan Habala, Hana Pačaiová
Acta Mechanica Slovaca 2024, 28(1):14-20 | DOI: 10.21496/ams.2024.014
This article deals with the issue of the incidence of musculoskeletal diseases in Slovakia in the long term and the possible relationship between their occurrence and the presence of psychological stress. According to statistics, these diseases are a long-term problem plaguing employees in various work sectors and age groups. Their occurrence contributes to the long-term incapacity for work of employees or to their work restrictions, which often require the reassignment of the affected employee to another job or even his or her complete exclusion from employment. This has a negative impact not only on the health of the employee, but also on the operation...
Impact of using FGM Materials for Improving the Efficiency of an Internal Combustion Engine
Maamar Mouheb, Ahmed Fellah, Mohamed Amine Khorchef, Mohamed Reda Larbaoui, Khadidja Boualem
Acta Mechanica Slovaca 2024, 28(1):6-13 | DOI: 10.21496/ams.2024.004
The biggest problem facing internal combustion engine is the decrease of energy efficiency due to thermal losses, which causes an increase in fuel consumption and operating cost, as well as a large amount of burned gas released with major environmental problems resulting. In this context, we will focus in this work about improving the efficiency to minimize all these problems, for this we propose to minimize thermal losses through the use of FGM materials. In this context, a steady state heat conduction analysis of functionally graded cylinder is conducted to present the advantages of using of functionally graded materials over the metallic materials...
The Impact of Annealing Process on the Mechanical Properties of TS550BA and TH550CA Steel Sheets
Emil Spišák, Janka Majerníková, Peter Mulidrán, František Ruda, Vladimír Rohaľ
Acta Mechanica Slovaca 2023, 27(4):76-84 | DOI: 10.21496/ams.2024.001
Packaging material is the most widely used material in the food industry, which is used to produce a variety of cans, caps, lids, and beverage containers. In this work, the effect of annealing process on the mechanical properties of thin steel sheets is evaluated. The mechanical properties and the effect of springback were investigated on two types of double reduced thin steel sheets. Batch annealed steel TS550BA and continuously annealed steel TH550CA, both steel types had a thickness of 0.18mm. Uniaxial tensile test, bulge test and springback test were used to evaluate the mechanical behavior of the selected steel plates. The bulge test was performed...
Modelling and Experimental Testing of a Solar Thermoelectric Refrigerator
Francis Onoroh, Uche Paul Onochie, Larry Orobome Agberegha
Acta Mechanica Slovaca 2023, 27(4):62-74 | DOI: 10.21496/ams.2023.034
This research centered on the design, simulation and testing of a solar thermoelectric refrigerator. Mathematical models of the system were derived and solved using MATLAB to predict the performance of the refrigerator at various operating conditions of applied voltage and temperature gradients. Simulations were carried out in order to test the system's effectiveness when powered with solar energy. Simulation results of the thermoelectric refrigeration showed the heat pumping capacities of the TEC1-12706 module as 42.6W, 38.9W, 35.3W and 31.7W at temperature gradients of 5°C, 10°C, 15°C and 20°C respectively, the heat dissipation capacities of the...
Business Intelligence and its Development From the Perspective of Publication in Scientific Journals
Dominika Sukopová, Jaroslava Kádárová, Lenka Vyrostková, Laura Lachvajderová
Acta Mechanica Slovaca 2023, 27(4):52-61 | DOI: 10.21496/ams.2023.038
This article presents a comprehensive analysis of the development and impact of Business Intelligence (BI) between 2018 and 2022. It focuses on examining research articles published in five reputable journals specified in the field of Business Information Systems. The study examines the development and impact of BI. How has the field of BI evolved over these years and what insights can be gained from its impact on decision making? This research delves into the nature of the growth of BI and its implications for modern businesses and offers valuable insights for practitioners and researchers alike. By categorizing the articles into key topics, methodologies,...
Optimizing Earth-Air Heat Exchangers for Sustainable Summer Cooling and Winter Heating
Mohamed Amine Khorchef, Mohamed Serier, Aboubakeur Benariba
Acta Mechanica Slovaca 2023, 27(4):42-50 | DOI: 10.21496/ams.2023.039
This study utilized a full factorial design with three factors at two levels each: thermal conductivity, pipe length, and air velocity. We aimed to identify optimal EAHE configurations for both summer cooling (maximum air temperature reduction) and winter heating (maximum temperature increase). Distinct optimal conditions emerged for each season. For summer cooling and winter heating, optimal configurations involved high thermal conductivity, moderate pipe length, and minimal air velocity. Statistical analysis revealed pipe length as the most influential factor on temperature in both seasons, explaining over 59% of the variability in winter and 49.43%...
Design of a Low-pressure Metal Hydride Reactor Designed for Hydralloy C5
Ivan Mihálik, Filip Duda, Šimon Hudák, Natália Jasminská, Marián Lázár
Acta Mechanica Slovaca 2023, 27(4):36-41 | DOI: 10.21496/ams.2023.035
In this article, individual options for the implementation of hydrogen storage systems in vehicles are analysed. In particular, the conventional methods are described and hydrogen storage systems that use metal hydride alloys are discussed. The article presents the design of a low-pressure pressure vessel with a maximum operating pressure of 3MPa, compliant with the STN EN 13322-2 requirements. The newly-designed metal hydride pressure vessel was subjected to a strength analysis in the Ansys Static Structural environment at a maximum test hydraulic pressure of 4.7MPa. The measurement data describing the amount of the stored hydrogen which was obtained...
Enhancing Piping System Reliability Through Material Upgrades and ANN-Based Damage Parameter Estimation
Mohammed Amine Belyamna, Abdelmoumene Guedri, Abdelhalim Aiiaoui, Chouaib Zeghida
Acta Mechanica Slovaca 2023, 27(4):22-35 | DOI: 10.21496/ams.2023.033
The objective of this study is to enhance the longevity of damaged or defective components through necessary repairs. In corrosive environments, stainless steels, such as 304 and 316NG austenitic stainless steel (SS), are preferred due to their chemical composition. Notably, 316SS contains a higher molybdenum content, resulting in improved resistance to pitting and crevice corrosion. The simulation of intergranular stress corrosion cracking (IGSCC) in SS piping relies on factors like applied and residual stresses, environmental conditions, and sensitization degree. To understand crack growth rates and times-to-initiation for each material, "damage...
Influence of the Number of Tanks on the Performance of a Domestic Solar Water Heater
Mohamed Lazreg, Touhami Baki, Driss Nehari
Acta Mechanica Slovaca 2023, 27(4):14-21 | DOI: 10.21496/ams.2023.037
A study with the TRNSYS software of solar water heater installations was simulated for the domestic hot water needs of an average family in the Mediterranean climate of the city of Oran in Algeria. Comparisons of systems with one tank and two tanks have shown similarities in the quantities of energy consumed and captured by the solar panels, but differences have been observed in the coverage of auxiliary energies. On the other hand, the two-tank system makes it possible to produce very significant temperature stratification.
Photocatalytic Efficiency Test Equipment
Dominik Novotný, Ján Kráľ
Acta Mechanica Slovaca 2023, 27(4):6-13 | DOI: 10.21496/ams.2023.036
This article deals with a description of pathogens, ways to combat pathogens, and a brief overview of the devices we use to eliminate them. The aim of the article is to describe the photocatalytic efficiency, which will result in the application of the given technology to a newly developed device - an antimicrobial device, the efficiency of which we will be able to determine by means of a photocatalytic efficiency test device where we will examine the given technology with the help of a mass spectrometer.
Forecast of the Temperature Variation of an Elastohydrodynamic Contact by the Simple Exponential Smoothing Model (SES)
Hanene Louahem M'sabah, Azzedine Bouzaouit, Sabrina Mattallah
Acta Mechanica Slovaca 2023, 27(3):70-76 | DOI: 10.21496/ams.2023.030
Lubrication is a crucial tool for industrial maintenance. By reducing friction between components, it also reduces wear on equipment.
Research into the methodology for measuring electromagnetic fields generated by base transceiver stations
Elena Lukac Jurgovska, Ervin Lumnitzer, Miriam Andrejiova
Acta Mechanica Slovaca 2023, 27(3):62-68 | DOI: 10.21496/ams.2023.027
The electric field strength is a legally defined, directly measurable quantity for the evaluation, assessment, and objectivity of electromagnetic fields in the environment. This contribution is devoted to the analysis of the temporal dependency of changes in the intensity of electric fields generated by base stations of mobile operators. It focuses mainly on the time interval, the location of the measuring point, and the selected day during the week in which the electric field effort measurement was performed. Measurements were made at the selected industrial site and at the designated measurement sites. Measurements were made on selective days of...
Formability Evaluation and Strain Distribution at the Limit Dome Height Test of Dual-Phase Steel
Miroslav Tomáš, Juliy Martyn Kulya, Vladimír Kokarda
Acta Mechanica Slovaca 2023, 27(3):54-61 | DOI: 10.21496/ams.2023.031
The article deals with the formability testing of dual-phase steel DP800 that is used for the production of parts used in the rear deformation zone of the car body. The thickness of the steel was 1.6mm, and the Limit Dome Height test was performed on an Erichsen 145-60 testing machine. Specimens of different widths were stretched up to the fracture, and the punch path and force were measured. Specimens were etched to create a deformation grid of dots in order to measure the strain distribution using the photogrammetric system Argus. Then, the simulation model of the LDH test was created, and the punch path was set to calculate the strain distribution...
Analysis of the Tribothermal and Mechanical Behavior of Copper-Steel and Brass-Steel Sliding Couples
Boubechou Choubeila, Bouchoucha Ali, Bouzaouit Azeddine
Acta Mechanica Slovaca 2023, 27(3):42-52 | DOI: 10.21496/ams.2023.032
This article deals with a comparative study of the thermomechanical behavior of copper-steel and brass-steel tribological couples, as a function of functional parameters: contact mode, dynamic torsor, contact kinematics and the materials making up the tribosystem. For this purpose, friction and wear tests were carried out using a pin-disc tribometer, in an atmospheric environment. This consists of a copper or brass pin rubbing dry against a rotating steel disc. A Comsol Multiphysics numerical code was used to evaluate contact temperature, mechanical stresses and deformations at the interface of the pairs. The results obtained show that the above-mentioned...