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Tkac J.,Alexander Dubcek University, Trencin
2010 International Conference on Applied Electronics, AE 2010 | Year: 2010

The paper deals with methods of contactless tachometry by radar sensors. The radar sensors are characterized by a good reliability and relatively high accuracy of measurements. The goal of the paper is to propose and realize the system which would manage to measure moving objects with a pulse radar and the Matlab software. Measuring of moving objects has been realized through the radar sensor which operates in an X-frequency band. The audio output of the radar sensor has been used for the velocity measurement and for the signal processing, a PC sound card and Matlab DAQ libraries have been used.

Barenyi I.,Alexander Dubcek University, Trencin
Engineering Review | Year: 2016

The article deals with two middle alloyed high strength cast steels and the possibility of their mechanical properties improvement with modification by titanium. The presented study has two main topics. The former is the evaluation of basic mechanical properties of modified and unmodified samples in normalizing and quenchedand-tempered states. The latter is the effect of modification exhibited on the nitridation process and parameters evaluated after nitridation as the course of micro hardness across nitridation layer, the depth of the layer and hardness of nitride surface.

Vojtovich S.,Alexander Dubcek University, Trencin
Engineering Economics | Year: 2013

This study deals with one of the current and relatively often discussed phenomenon, which accompanies economic and social development in both developed and economically struggling countries. The economic development of Slovakia is no exception. The analysis of both unemployment as an economic and social phenomenon and unemployment trends is conducted in relation to the period of stabilization and relative economic growth, which followed after the transformation of economic systems in countries of Central and Eastern Europe. The main objects of this analysis are primarily trends in the economic development, trends in the job creation, and the impact of direct foreign investments on the development of unemployment.Migration of labour force abroad is another important variable entering the analysis. The focus is placed predominantly on the migration flows into foreign countries and also on their impact on the development of unemployment rate. From the previous analyses and observations of real processes occurring in this particular field we know that under certain circumstances high unemployment rate results in the growth of migration flows of labour force abroad. But during the studied period under the conditions of relatively quick economic growth in Central and Eastern Europe we can observe different trends when it comes to the connection between unemployment rate, economic growth and migration flows. Trends in the economic development during this period, in the development of unemployment rate and in the emigration flows and their causality do not match our knowledge and ideas about these phenomena and processes in the entrepreneurial, political or academic environment. Therefore, this study aims to conduct an analysis of the above mentioned phenomena and processes and offer a reasoned and adequate concept about the trends in their development. © 2013, Kauno Technologijos Universitetas. All rights reserved.

Pernis R.,Alexander Dubcek University, Trencin
Acta Metallurgica Slovaca | Year: 2011

There is one subsistent group of relations based on theoretical knowledge which are used for the average contact pressure calculation on smooth rolls. The second group of relations is generated by empirical equations valid in restricted area of application. The new hypothesis of contact pressure distribution in dependence on rolling conditions is presented in this submission. A new term of non-dimensional value has been defined as relative stress. An equation for the average contact pressure calculation, presented by author moves the mathematical theory of rolling closer to practice. The relative stress is dependant on ratio ld/hav, reduction intensity and friction coefficient. The equation of relative stress in average contact pressure calculation allows for the presence of a minimum. The verification of new hypothesis of contact pressure distribution is in good consent with data measured in rolling practice.

Kvasnica P.,Alexander Dubcek University, Trencin
Computing and Informatics | Year: 2014

In this paper, the use of continuous mathematical models of an aircraft in an aircraft simulator is described. The models are of lower degree and less time-consuming for calculation. Computer implementation of the models capable to work faster and more accurately and efficiently is also described. The suggested approach allows to achieve the required precision at accelerated simulation speed using the continuous mathematical models of an aircraft. Frequency of the computation of continuous mathematical models of an aircraft is higher, reaching up to 200 times per second. The main focus of the paper is designing continuous mathematical models of an aircraft, their simulation and visualization in aircraft simulators. Current mathematical models of a control of objects motion are based on aircraft aerodynamics. In our approach, these models have impact on the quality and completeness of simulation process and are crucial for computer modeling and visualization of equations of the continuous mathematical models of an aircraft. In the paper, creating continuous mathematical models of an aircraft and the way of visualization of simulation results are described in detail. The main aim of computer simulation of continuous mathematical models of an aircraft is pilots training. Aircraft simulator plays a key role in the process of pilots training; it enables pilots to control the aircraft and its equipment. Standard computer with a graphic processing unit for the visualization results from continuous mathematical models of an aircraft can be utilized.

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