MM Science Journal, October 2020

REMOVING ADDITIVE NOISE IN MEASUREMENTS OF LOW SOUND PRESSURE LEVELS

Martin Nevrela, Michal Weisz, Jan Szweda, Martin Vasina
Keywords: thermal noise | microphone | extremely low noise | sound pressure level | Acoustics

Noise belongs among the negative phenomena in our environment and can have a negative effect on human health. Excessive noise occurs in many areas, e.g. in transport, aeronautics, and during manufacturing processes. It is often necessary to meet specified noise limits. Acoustic measurements are carried out in many cases, e.g. in order to evaluate the sound absorption properties of investigated materials (…)

MECHANICAL PROPERTIES OF BIOPOLYMER COMPOSITE WITH NATURAL FIBERS SURFACE MODIFIED BY LOW-TEMPERATURE PLASMA

Jiri Habr, Petr Lenfeld, Lubos Behalek, Martin Boruvka, Pavel Brdlik
Keywords: Plasma | coconut | natural fibers | PLA | Biocomposite

The paper deals with the evaluation of mechanical properties of a biopolymer composite, where a low-temperature plasma, atmospheric dielectric barrier discharge (DBD) physical treatment was used to improve adhesion at the interface between the polymer and natural fibers. The polymer composite matrix was PLA polymer from NatureWorks LLC. The reinforcing filler were natural coconut fibers, which were in t (…)

DIAGNOSTICS OF AUTOMATED TECHNOLOGICAL DEVICES

Jozef Peterka, Yury Rafailovich Nikitin, Pavol Bozek
Keywords: Artificial Intelligence | Computer Numerical Control | neural network | mechatronic systems | technological devices | diagnostic

Automated technological devices need diagnostics. At present, it is possible and necessary to use a wide range of sensors, computing systems and artificial intelligence methods based on neural networks, fuzzy inference systems in diagnostic systems. This paper proposes three models of information processes for diagnosing mechatronic systems - parallel, sequential and combined. To diagnose the nodes of m (…)

NUMERICAL ANALYSIS OF THE FLOW CONDITIONS IN THE AIR DISTRIBUTION ELEMENT

Maria Carnogurska, Miroslav Prihoda, Daniela Popcakova
Keywords: turbulence models | computational fluid dynamics | numerical analysis | velocity conditions | air distribution element

The article presents the results of a numerical analysis of the flow conditions in the air distribution element in a combined refrigerator and freezer. A numerical analysis was carried out using the boundary conditions identified through an experiment. The article includes an analysis of the impact of the mesh type and the used turbulence models on the profile of the air flow velocity in the outlet open (…)

DEVELOPMENT OF IMAGE PROCESING SYSTEM FOR PERSON DETECTION

Dominik Stursa, Daniel Honc, Peter Dolezel
Keywords: Pattern recognition | image processing | Person detection

With the rise of modern technology in computer science and engineering, as well as with the growing population in big cities around the world, many new approaches for person detection have become a very interesting and demanding topic. Person detection is a necessary building block for people monitoring systems and, therefore, various detection methods must be inspected comprehensively in order to selec (…)

MODELING OF THE HEAT DISSIPATION PROCESS OF COMPOSITE MATERIALS DURING STABILIZATION OF THE STRUCTURE USING THE EXAMPLE OF NON-AUTOCLAVED FOAM CONCRETE

Sergey V. Fedosov, Kseniia L. Domnina, Maros Soldan, Maxim O. Bakanov
Keywords: heat and mass transfer | hydration | heat release | foam concrete | cellular composite

The article presents the features of mathematical modeling of the heat release during the hardening of composite cellular materials using the example of non-autoclaved foam concrete. The reactions of hardening and structure formation in foam concrete are exothermic and are called hydration reactions. The article lists the technological factors affecting the heat release during hydration. The basis for r (…)

MODEL OF CYCLICAL MONITORING AND MANAGING OF LARGE-SCALE FIRES AND EMERGENCIES FOR EVALUATION OF THE REQUIRED NUMBER OF UNMANNED AIRCRAFT SYSTEMS

Denis V. Tarakanov, Vanessa Prajova, Maksim O. Bakanov, Aleksandr V. Kuznetsov, Ksenia L. Domnina
Keywords: reserving the monitoring tools | information support | monitoring planning

In this article, based on the forecast of the state dynamics of control systems with the use of cellular automata, we consider the obtained results that provide the theoretical basis for the development of a conceptual model of forming a reserve of fire monitoring tools. The article identifies analytical dependences of the assessment of the limit states of the monitoring system for solving the challenge (…)

POSSIBILITY AND MEASUREMENT OF EARTHQUAKE PREDICTION BASED ON TREND STUDY OF TOTAL ELECTRON CONTENT (TEC) OF EARTH'S IONOSPHERE

Volodymyr Nahornyi, Anton Panda, Iveta Pandova
Keywords: electron content of the ionosphere | trend | Earthquakes forecasting

The article discusses a new breakthrough methodology for forecasting events and phenomena that are diverse in their physical nature. The article uses the total electron content trends (TEC) of the ionosphere as initial data for earthquake forecasting. The total electron content of the Earth’s ionosphere is a good indicator of its state and its dynamics. It has been found that the most effective fo (…)

PROSPECTS OF MODERN CASTING METHODS FOR CASES WITH COMPLEX INTERNAL CAVITY

Tanyana Nikolaevna Ivanova, Zuzana Sagova, Aleksandr Ivanovich Korshunov
Keywords: lost-foam casting | lost-wax casting | permanent mold casting | casting into molds made of cold-hardening mixtures | sand mold casting | material utilization ratio | modelling

Several methods of production of castings have been studied via the example of a case part, an axial piston pump back-end cover, namely. These methods include sand mold casting, casting into molds made of cold-hardening mixtures, permanent mold casting, lost-wax casting, lost-foam casting. We have considered only those casting methods, which ensure obtaining internal cavities with curved axes without th (…)

CONTROL OF THE TECHNOLOGICAL PROCESS OF DRILLING

Tanyana Nikolaevna Ivanova, Pavol Bozek, Aleksandr Ivanovich Korshunov, Vladimir Pavlovich Koretckiy
Keywords: radius of curvature | deviation system | directional well | rotary steerable system

Drilling with a rotary steerable system (RSS), the mechanical drilling speed increases by two times compared to drilling with a screw bottom-hole motor, which provides significant savings drilling-time. The effective length of the horizontal elbow increases, which enables to increase the production rate more than twice. It is found that in comparison with the bottom hole motor, RSS provides drilling smo (…)

BLADE LOAD ANALYSIS ON SWIRL TURBINE RUNNER WITH NONUNIFORM BLADE CASCADE

Jakub Starecek, Miloslav Haluza, Pavel Rudolf
Keywords: FEM | cfd | nonuniform blade cascade | swirl turbine

Blade load analysis of the turbine blades is generally very crucial for hydraulic machine designs, especially in a case of axial turbines, where the shroud is missing. The torque in this case is transmitted only by the blade pivots or fixed support to hub. Blade loading can be especially significant for off-design operating regimes. Modulation of the excitation frequencies and pressure pulsations is ena (…)

AN AUTOMATIC ERROR SURFACE DIAGNOSTICS DURING TURNING MACHINING OPERATION USING LASER SENSOR

Kamil Zidek, Jan Pitel, Alexander Hosovsky, Natalia Lishchenko, Martin Miskiv-Pavlik, Peter Lazorik, Jozef Zbihej
Keywords: turning | industry 4.0 | quality control | Laser sensors | automation

The paper deals with the design of an automated measuring and error detection system integrated into the turning machine. The experimental measuring device is based on a laser sensor with data transfer to the PLC control system. The main advantage of the designed experimental system is the possibility of measuring during the whole production process. The start position for the next product turn is index (…)

INNOVATION AND RECYCLING OF ALUMINIUM CASTINGS IN THE FORM OF PLASTIC REPAIR METAL ADDITION FOLLOWED BY MACHINING

Anton Panda, Lukas Androvic, Iveta Pandova
Keywords: damage | material loss | procedure | waste | material | process | Aluminium

Nowadays, recycling is a very often discussed topic though its realization varies. One way the recycled material has to be collected, subsequently sorted, melted, cast repeatedly and the casting has to be respectively machined. Otherwise given casting can be recycled by repair in a form of material adding. This way of repair is suitable, especially where the product of the casting is degraded due to mat (…)

POPULATION-BASED SHAPE OPTIMIZATION OF A CENTRIFUGAL PUMP IMPELLER

Prokop Moravec, Pavel Rudolf
Keywords:   Mg alloy | cfd | Particle Swarm Optimization | pump impeller | centrifugal pump | multi-objective optimization | shape optimization

A shape optimization problem is increasingly popular in various parts of industry and academia. Several shape optimization approaches emerged in the past few years. Population-based methods (PPM) are among them, with convenient attributes and characteristics that lead to a discovery of proper solutions of investigated problems. Crucial quality of PPM lies primarily in number of randomly scattered indivi (…)