Univerzitná knižnica - Vedecké odborné časopisy

The presented article is focused on analysis of running properties of a modified railway vehicle and its components due to a change of the powertrain and influence of the mutual effects in a wheel/rail contact. The modification of a vehicle consists in a change of a standard diesel-electric powertrain by a new powertrain, which includes as a source of power the hydrogen fuel cells. This modification represents a quite significant modification of a vehicle structure, mainly a change of mass and position of centre of gravity individual articles of a vehicle. The analysis of running properties is performed by means of simulation computations in a commercial simulation software Simpack. Simulation model of a vehicle is called as a multibody model. This model consists of rigid bodies, which are connected by flexible modelling elements. Simulation analyses are performed for an original vehicle and for vehicle with hydrogen fuel cells. There are analysed cases of running on two types of tracks. There is found oud based on the obtained results, that the modified vehicle with the hydrogen cells has similar force distribution in a wheel/rail contact, however, the axle load of the modified vehicle does not meet required criteria.

The presented research is aimed at the derivation of a mathematical model of diesel-mechanical drivetrain of a rail vehicle. It is derived by means of the Lagrange’s equations of the second kind. The derived mathematical model allows to understand the essential principle of the derivation of the mathematical model of the diesel-mechanical drivetrain of a rail vehicle, an application of the numerical mathematical methods for the solving the equations of motion and for evaluation of the wanted outputs quantities, such as waveforms of revolutions and torques of shafts and others.

This paper deals with flight control and stability surfaces, which is a comprehensive overview of control and stability surfaces of an aeroplane, especially three main control surfaces elevator, ailerons and rudder. These are analysed from the perspective of functions, locations, divisions and aeromechanics. Part of the paper is dedicated to the definition of aircraft, the division of aircraft and the structure of the aeroplane.

Štúdium mechanických vlastností strojných súčiastok s malou hustotou vnútornej výplne vyrobených metódou 3D tlače, 2. časť The article is focused on study of mechanical properties of machine components produced by the 3D printing on FDM (FUSED DEPOSITION MATERIAL) devices by means of a computational model. The article brings details of results of performed tests and a created model for strength analysis using the finite element method. Components of machine produced by means of the 3D printing technology allow to reduce them weight. Currently, this technology is applied not only for production of plastic components, but it is possible to apply it for metal components even other kind of materials. ----------------------------------------------------------------------------------------------------- Vehicle passage over an uneven road Evaluation of mechanical vibration of a vehicle is still up to date. Mechanical vibrations influence dynamic properties of vehicles. They are raised during vehicle driving over an uneven road. Practically, vibrations are deflections of individual components of vehicles. They can lead to slight oscillations or even to significant shocks, which can cause adverse passenger ride comfort, decreased driving safety and extraordinary loading of a road. This article is focused on analysing of vehicle running through an individual road irregularity by means of a mathematical approach as well as on presentation of results of dynamic analysis of a passenger car using a computational model. ----------------------------------------------------------------------------------------------------- Chyby ingotov a možnosti ich eliminácie The paper deals with the production of forging ingots. The basic and necessary data that shed light on the issue are given. The text of the paper presents some selected errors arising in the production of ingots and the possibility of their elimination. The text of the paper is supplemented by pictures and the necessary mathematical relations describing the process. ----------------------------------------------------------------------------------------------------- Návrh brzdového výstroja vagóna s redukovaným počtom spojov: 2. variant This paper deals with the problem of compactization of braking equipment i.e. reduction of pipe joints. The first part contains general look of division of train brakes. The second part contains descriptions of each component of pneumatic part of brake equipment such as, distributor valve, limiting valve etc. The third part deals with descriptions of individual design solutions. The main goal is construction solution in order to reduce pipe joints of brake equipment. This paper represents a continuation of the research presented in the previous number of the journal. ----------------------------------------------------------------------------------------------------- Konštrukcia stĺpového žeriava pre manipuláciu s kalovými čerpadlami a matematický opis závislosti tiaže bremena a ovládacej sily The article brings a technical description of a suspension for manipulation with sludge pumps. It serves for using in the power plant in Jaslovské Bohunice. It is the object for chemical treatment of water belonging to the V2 block. The suspension is used in regular revisions checks of sludge pumps, the Type 80 KDFU150 9.5-A0-03 and for the needed manipulation with them during their operation. This suspension is designed for the maximal load of 120 kg and it was damaged during operation, because it was not designed for all consequences during operation with a sludge pump. It was causing gradual sedimentation of sludge around suction valves of the pump. It has led to the fact, that the pump was stuck to the tank bottom. Then, the lifting of the pump needed even four-times higher force in comparison with the ideal state. Hence, the suspension was not dimensioned for such the great load. Therefore, an optimization is important. ----------------------------------------------------------------------------------------------------- Hodnotenie pórovitosti odliatku vyrábaného vysokotlakovým odlievaním Thus, high-pressure casting of aluminum alloys using a machine with a cold vertical chamber has over time become the most widely used and economical technology. This method has become attractive especially in the production of complex, dimensionally accurate and thin-walled castings. In the experimental part, individual samples of castings, which were cast by the company Rosenberg-Slovakia s.r.o. high-pressure casting, where the castings differed from each other by changing the height of the tube and gradually increasing the maximum speed of the piston. Evaluation of porosity and microporosity was performed on experimental samples. The most advantageous speed among the used speeds in terms of macroporosity and the associated visual control, but with a slight decrease in microporosity in the more critical area, the speed was 3 m∙s-1. ----------------------------------------------------------------------------------------------------- Blechschneiden mit Wärmeanwendung The article deals with to in theoretical part described sheet problematic. In the experimental part deals with search to influence temperature on heating applique. In the contribution to are integrated photos the shears surfaces and is being done valuation results obtained. ----------------------------------------------------------------------------------------------------- Teoretická analýza premeny slnečnej energie na teplo s aplikáciou pre rodinný dom In low-energy and passive buildings, it is essential that energy demand is covered by renewable energy. Buildings require energy in the form of heat and electricity, and the use of solar energy is important to achieve a clean zero energy balance. In projects with ambitious energy targets or limited available areas for local energy production, solar and photovoltaic installations will be a suitable solution in terms of reducing primary energy demand. This article deals with the analysis of the conversion of solar energy into heat in order to reduce the primary energy demand of a building and achieve its net zero energy balance. ----------------------------------------------------------------------------------------------------- Sheet metal bending process at three different temperatures The field of sheet metal bending is an important area of metal forming and therefore considerable attention must be paid to this area, as many similar tasks need to be solved in production practice. This is exactly what the published article, which deals with the area of the sheet metal bending process, should help. The text describes experimental works and their results, which are supplemented by tables and illustrated by graphs of bending forces. the bending process is done in three thermal modes: normal temperature, minus temperature and hot bend. Five samples were bent for each of these groups, which sufficiently illustrate the investigated process. The paper is supplemented by a discussion of the results and in the end an evaluation of the experiments is made. ----------------------------------------------------------------------------------------------------- Reakcia hliníka v prostredí zvýšeného pH Aluminium and most alloys are durable metals. In slightly aggressive atmospheres, passive, electrically non-conductive corrosive layers form on the surface. In heavily polluted environments, corrosion can occur with larger corrosion products, which do not penetrate deeper into the material even after a long time. The subject of the article is aluminium mesh, on which a special layer is formed, resp. a shell that reduces its life. The mesh is used in the paper industry, where it is exposed to acidic, dusty and moderately warm environments. Due to the effect of this environment in production, a brittle layer of shell character was created on the material. ----------------------------------------------------------------------------------------------------- Analýza viacfázových modelov transportu tepla v programe ANSYS Fluent The paper is focused on the analysis of multiphase models of heat transfer in program ANSYS Fluent, because the phenomena of multiphase flow can be observed in many engineering and biological systems. With our rapid progress in engineering technologies, the requirements for the accuracy of the calculations of the physical phenomena that take place in them, have increased. However, it is very difficult to detect two-phase flow by experimental measurements, and therefore numerical simulations are usually performed with experimental measurements, which can contribute to a better physical understanding of the complex phenomena of phase changes. The aim of the article is to introduce the reader to the issue of multiphase flow modelling in the ANSYS Fluent program and the parameter, which is used to correlate CFD simulation, so that it best describes the real experiment. ----------------------------------------------------------------------------------------------------- Fatigue properties of welded high-strength steels This article informs about the experience of the authors in the area of the fatigue life of the welded joints. We are aiming at the welds of the high-strength steel S960 QL. The welds are created by unconventional technologies utilizing the laser and electron beams. The analysis of the residual stresses, assessment of the strength and micro-hardness of the material tested around the welds is also part of this study. The experimental research of the tested material´s fatigue life and welded joints is realized on the samples loaded by cyclic bending and cyclic torsion. The measurement results are processed in the form of the S-N curves and compared with the current regulations issued by the International Institute of Welding in the form of the FAT curves. ----------------------------------------------------------------------------------------------------- Energetické zhodnocovanie komunálneho odpadu na Slovensku Most research is focused on improving the treatment of municipal solid waste (MSW) to obtain usable energy. Pyrolysis technology can not only reduce the volume of MSW, but also produce pyrolysis oil, pyrolysis gas and carbon, which have high calorific values and application properties and are widely used in industrial activities. In this paper, we focus on the research of MSW pyrolysis according to its composition. The components of MSW, including plastics, biomass, and rubber, on pyrolysis products are summarized. In addition, the pyrolysis of raw and extracted MSW in Slovakia is discussed. The article also mentions an existing processing plant for waste recovery using a pyrolysis process. This plant will help us better design our own equipment for the evaluation of MSW. ----------------------------------------------------------------------------------------------------- Prevodové pomery pri ovládaní mechanizmu dávkovača rúrok This article deals with the issue of selecting the gear ratio of the linear actuator as well as the lever transmission of the tube dispenser control mechanism. The genesis of the development of a device for secondary pipe cutting, of which a dispenser is a part, is explained. The forces for actuating the dispenser are calculated and a specific actuator model is selected from the catalogue. ----------------------------------------------------------------------------------------------------- Koncepčný návrh bezdrôtového monitorovacieho systému emisií pre vykurovacie zariadenia na tuhé palivá The article presents a conceptual design of a state-of-the-art emission monitoring system that shall monitor emissions produced by household boilers directly. The aim of the article is to provide low-cost, reliable, and accurate emission data at remote locations, assisting the 2050 Climate-Neutral target set by the European Commission. The sensor devices shall monitor emission parameters such as ozone, carbon dioxide concentration and particle concentrations, specifically concentrations PM2,5 and PM10. Modern "home-made" air quality devices do exist within the market, however, only are applied in indoor climates. The environment within the exhaust of boilers, fireplaces or other heating devices is significantly more hostile, which brings an exciting engineering challenge. The paper first presents a conceptual design of the interface, sensors, and telecommunication unit. Followingly, two CAD models are presented including two attachment systems. The paper later demonstrates a series of future experiments including the setup, the necessary components, and specific aims. In the conclusion of the paper, the data representation is presented along possible countermeasures and strategies that can be done to correct dangerously high levels of measured emissions by the sensors, ultimately aiding to reach the EU Climate target of 2030 and climate neutrality. ----------------------------------------------------------------------------------------------------- Analýza vplyvu tvaru telesa odlievaných čelných ozubených kolies na deformáciu ozubenia Gears are designed in various design types. In accordance with the careful design of the gearing, it is necessary to address the issue of designing a suitable shape of the gear body. In the case of the necessary choice of a lightened gear body, it is necessary to maintain the stiffness of the body itself, but also to remember and take into account the necessary meshing stiffness. The work is focused on large cast dimension gears, made with relief. The shape of the gear body depends on several factors such as the size of the wheel, the material, the method of manufacture or use of the gear. The paper is devoted to the analysis of the influence of the basic parameters of the body of the cast spur gear on the deformation and thus also the meshing stiffness of the gearing. ----------------------------------------------------------------------------------------------------- Konvenčné spôsoby výroby vodíka z fosílnych palív Article deals with commonly used conventional hydrogen production methods like steam reformation, partially oxidation method, auto thermal reformation or, pyrolysis of carbohydrates. This article describes these methods their efficiency and reveals possible improvements to the future based on lowering of impact on our climate by the possibility of carbon capture systems and lowering of energy consumption of the processes, using membranes and using lower temperatures at the process. ----------------------------------------------------------------------------------------------------- Hodnotenie vybraných vlastností hliníkovej zliatiny AlSi5Cu2Mg legovanej zirkóniom The aim of this paper was to analyse the impact of different zirconium content (0.10; 0.15; 0.20 and 0.25 wt. %) on microstructure, mechanical and physical properties of AlSi5Cu2Mg aluminium alloy. The results showed that increasing zirconium content had no effect on the increase in ultimate tensile strength, yield strength, hardness and thermal conductivity values of as-cast samples. After heat treatment, only slight improvement in hardness values compared to as-cast samples were documented in variants with 0.10; 0.15 and 0.20 wt. % Zr. Zirconium rich intermetallic phases were observed in shape of separate thick needles or as a cluster of two crossed thinner needles with a length of 16 to 20 µm. SEM observation showed that these phases crystalized near to the intermetallic phases based on Cu and Fe and at the edges of eutectic silicon regions. ----------------------------------------------------------------------------------------------------- Trendy v znižovaní reoxidačných procesov vo vtokovej sústave počas odlievania Al zliatin Reoxidation processes are one of the main problems influence the final casting quality. The oxid layer can be entrained into melt volume by turbulence, remain in the solidificated casting and negatively affect mechanical properties of the casting. The paper focused on trends in reduction of reoxidation processes during pouring. The naturally pressurized gating system with filter or unconventional elements appears to be a suitable for reduction of reoxidation. ----------------------------------------------------------------------------------------------------- Prístrešok nad terasou - konštrukčný návrh a pevnostná analýza The aim of the paper is to create a structural design and stress analysis of a shelter above the terrace attached to the family house with respect to the specified parameters and to perform its strength analysis. In the theoretical part, the paper deals with the summarizes and characterizes the current designs of terrace shelters, various materials and technological possibilities of the solution and deals with loads. Furthermore, the practical part contains structural design of the pergola model from the CAD system, the analytical model with the results of static and modal analysis, and the eigenvalue buckling analysis. ----------------------------------------------------------------------------------------------------- Perspektívy uplatnenia modularity pri návrhu pohonných systémov v mechanických terapeutických zariadeniach The field of biomedical engineering, called rehabilitation engineering, deals with the design and construction of devices that help the disabled at various stages of the rehabilitation process. Rehabilitation engineering deals with the design and engineering of technical equipment that is helpful to disabled people in the various stages of the rehabilitation process. It is a set of engineering activities associated with the design, implementation and operation of technical means designed to support rehabilitation functions. A drive system is a necessary and necessary part of designing a rehabilitation facility ----------------------------------------------------------------------------------------------------- Heat sources for electron beam welding Nowadays, welding technologies based on the high energy electron beam are able to produce weld joints with very narrow heat affected zone. During welding procedure, softening phenomenon can occur in the heat affected zones and it could lead to the degradation of the mechanical properties of the final joint. The aim of this paper is to investigate the effect of heat source shape on the temperature distribution in an aluminium alloy during electron beam welding. We will vary the diameter of the beam shaped heat source at constant penetration. We investigate the temperature cycles for different heat sources in terms of maximum temperature. ----------------------------------------------------------------------------------------------------- Vplyv metód a technológií riadenia výrobných procesov na marketingovú stratégiu spoločnosti This article focuses on the technologies and methods used to manage the production process and their impact on the implementation of the marketing strategy of the manufacturing company. The marketing strategy aims to combine the market potential, desires, needs and wishes of customers with the goals and intentions of the company. It includes tools, steps and procedures that can bring real customers who will return, as well as the desired profit and the fulfillment of predetermined goals. We must also not forget how the product is produced and what technologies and methods control the production processes, because this is one of the elements of competitive advantage. Marketing is no longer just about the ability to compete and present the company in the market, but also about communication and how the customer and the company respond flexibly to customer requirements. Therefore, the processes in the company must be set up correctly and work without serious errors. ----------------------------------------------------------------------------------------------------- Vplyv tepelného spracovania na morfológiu intermetalických fáz v zliatinách Al-Si-Cu-Mg The present study was undertaken to examine the effect of iron, copper and magnesium on the morphology of intermetallic phases of Al-Si-Cu-Mg-based alloys under different heat treatment conditions. Due to the heat treatment T5, there isn´t significant change in the morphology of the intermetallic phases Mg2Si and Al2Cu, which is beneficial for the resulting mechanical properties of the castings. Further, spheroidization of eutectic silicon is not noted. In general, precipitation hardening of Al-Si based alloys, due to the presence of intermetallic phase Mg2Si and Al2Cu is a result of heat treatment T6. The morphology of Fe-rich phases is not changed by T6. The possitive effect of heat treatment on the morphology of Fe-rich phases is recorded with the simultaneous effect of additive elements such as Mn, Zr, Co. The ability to predict intermetallic phases is important in terms of determining the resulting mechanical properties of Al-Si-Cu-Mg castings. ----------------------------------------------------------------------------------------------------- Vplyv zmeny stratégie na riadenie podnikových procesov This article focuses on the impact of a strategy change on the business process management of a manufacturing company. A strategy is a term for a long-term plan created to achieve one or more goals. The strategy serves both to transfer the requirements of the owners to the management of the organization and to the management of the organization to organize, unify and guide the behaviour and actions of all people in all parts of the organization. The main processes that fulfil the basic strategic direction of the organization and their outputs are intended for external customers. The adopted strategies gradually influenced the set business processes, which needed to be gradually adapted and other action plans applied in the assessment of the business case. The research confirms that the adopted strategies gradually influenced the set business processes, which need to be effectively adapted.

Univerzitná knižnica - Vedecké odborné časopisy

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