Communications - Scientific Letters of the University of Zilina, 2018 (vol. 20), issue 4
Operation and Economics in Transport
Strategic Advertising Management: The Case of the Transportation and Storage Market in the Czech Republic
Daria Gunina, Vladislav Bina, Michal Novak
Communications - Scientific Letters of the University of Zilina 2018, 20(4):3-9 | DOI: 10.26552/com.C.2018.4.3-9 
The aim of this study is to analyse the advertising strategy on the transportation and storage market in the Czech Republic. The study provides information and knowledge of seasonal advertising scheduling by answering three research questions. The statistical analysis is based on a research sample of 840,204 advertisements aired in 2013-2017. The results of the study show different scheduling patterns of subcategories in the transportation and storage market. They also point out that subcategories in the transportation and storage NACE category are different. Therefore, marketing researchers should take this knowledge into account in their generalisations.
International Logistics Performance Based on the DEA Analysis
Marjan Sternad, Tomas Skrucany, Borut Jereb
Communications - Scientific Letters of the University of Zilina 2018, 20(4):10-15 | DOI: 10.26552/com.C.2018.4.10-15
Logistics is a very important service, which can influence the international trade. However, the rates in the development of international activities vary by country. In developing countries, the share of the logistics services is increasing, while the share of manufacturing activities, especially those with the lower added value, is declining due to the relocation of production to other countries. In order to achieve competitive advantages in the logistics sector, the development of logistics services with the higher added value is required. The effectiveness of logistics processes is very important for international competitiveness. In the paper,...
Mechanical Engineering in Transport
Intelligent Logistics for Intelligent Production Systems
Martin Krajcovic, Patrik Grznar, Miroslav Fusko, Radovan Skokan
Communications - Scientific Letters of the University of Zilina 2018, 20(4):16-23 | DOI: 10.26552/com.C.2018.4.16-23
The main topic of the submitted paper is intelligent logistics and its integration into production systems. In the beginning, the problem that lies in the inadequate knowledge of the internal state has been defined. The new society-wide trends that will originate in a few years are also outlined. Those trends will affect factories and their logistics systems on a large scale. Therefore, it is necessary to have a strategy that takes these new trends into consideration. In this manuscript, is described a strategy for intelligent production systems, as well as technologies for different types of production-logistic strategies. Many of these technologies...
Vibration Analysis by the Wigner-Ville Transformation Method
Jaroslav Smutny, Viktor Nohal, Daniela Vukusicova, Herbert Seelmann
Communications - Scientific Letters of the University of Zilina 2018, 20(4):24-28 | DOI: 10.26552/com.C.2018.4.24-28
This paper deals with description and application of the Wigner-Ville transformation for vibration analysis. This transformation belongs to the group of non-linear time-frequency processes. Thanks to its properties, it may be successfully used in the area of non-stationary and transitional signals describing various natural processes. The use in the field of the railway constructions testing represents a quite an interesting application area of the transformation. This paper contains mathematical analysis of the transformation, a case study and practical experience obtained and recommendations for its practical use.
Gas Metal Arc Welding of Thermo-Mechanically Controlled Processed S960MC Steel Thin Sheets with Different Welding Parameters
Michal Jambor, Frantisek Novy, Milos Mician, Libor Trsko, Otakar Bokuvka, Filip Pastorek, Daniel Harmaniak
Communications - Scientific Letters of the University of Zilina 2018, 20(4):29-35 | DOI: 10.26552/com.C.2018.4.29-35
In this paper are presented results of mechanical properties evaluation of the thin sheets welds made of the S960MC TMCP steel, which were executed using the GMAW procedure with different process parameters. The microstructural changes in the heat affected zone (HAZ) were evaluated, as well. The microstructural observation revealed significant changes in the HAZ and the three main zones, coarse grain, fine grain and intercritical (CGHAZ, FGHAZ and ICHAZ) were identified in the HAZ for both sets of tested welding parameters. Evaluation of the micro-hardness showed significant reduction of the micro-hardness in the ICHAZ, for both tested states, and...
Mathematical Modelling of Shafts in Drives
Petr Hruby, Tomas Nahlik, Dana Smetanova
Communications - Scientific Letters of the University of Zilina 2018, 20(4):36-40 | DOI: 10.26552/com.C.2018.4.36-40
Propeller shafts of the vehicle's drive transmit a torque to relatively large distances. The shafts are basically long and slender and must be dimensioned not only in terms of torsional stress, but it is also necessary to monitor their resistance to lateral vibration.In the paper, a simple model (of the solved problem) is constructed by the method of physical discretization, which is evident from the nature of the centrifugal force fields' influence on the spectral properties of the shaft. An analytical solving of speed resonances prop shafts test model (whose aim is to obtain values for verification subsequently processed models based on the transfer-matrix...
Influence of Physical-Metallurgical Factors on Resistance of API Carbon Steels to Sulphide Stress Cracking
Petr Jonsta, Zdenek Jonsta, Irena Vlckova, Jaroslav Sojka
Communications - Scientific Letters of the University of Zilina 2018, 20(4):41-46 | DOI: 10.26552/com.C.2018.4.41-46
The paper deals with the influence of physical-metallurgical factors on resistance of the X52 and X70 steels in accordance with API 5L to sulphide stress cracking. The resistance against this kind of damage is relatively clearly claimed by usually used approach in this field by the tensile strength of steel, its hardness level, respectively. However, the experimental results had shown that the microstructural parameters are also the significant factors, which affect the resistance of steels to sulphide stress cracking. It was found that the quenching and tempering can significantly increase the resistance to sulphide cracking as in the case of hydrogen...
Evaluation of Mechanical Properties of the Two PVC Conveyor Belts
Nada Bojic, Ruzica Nikolic, Milan Banic, Branislav Hadzima
Communications - Scientific Letters of the University of Zilina 2018, 20(4):47-51 | DOI: 10.26552/com.C.2018.4.47-51
Conveyor belts with woven plastic belts, aimed for general applications, are very economical transporting means for longer distances. During the operation, the conveyor belts are subjected to various mechanical loadings. The consequences of those loadings are increased stretching of the belt and change of its tensile strength, which negatively affect the proper functioning of the transporter. To avoid the irregularities in the conveyor belt's operation, the tensile properties of the two plastic woven belts were tested (maximal force, maximal extension, breaking force and extension at break). In that way the conditions of the two belts were established....
Influence of the Heat Treatment on the Microstructure, Mechanical Properties and Fatigue Behavior of Additively Manufactured Ti6Al4V Alloy
Martin Frkan, Radomila Konecna, Gianni Nicoletto
Communications - Scientific Letters of the University of Zilina 2018, 20(4):52-57 | DOI: 10.26552/com.C.2018.4.52-57
This contribution deals with the selective laser melting (SLM), which is one of the additive manufacturing (AM) technologies enabling the production of complex parts from metal powder, layer-by-layer wise. This technology uses laser as source of energy to melt a powder to compact state. Properties of final products can be significantly influenced by the process parameters and post-fabricated heat treatments. The purpose of this study is to determine the effect of a heat treatment on properties of the Ti6Al4V alloy specimens manufactured by Eosint M280 machine by the SLM. Three sets of specimens, treated at different temperatures (730 ˚C, 900...
Strength Analysis of a Freight Bogie Frame under the Defined Load Cases
Jan Dizo, Miroslav Blatnicky, Jozef Harusinec, Alfred Pavlik, Lukas Smetanka
Communications - Scientific Letters of the University of Zilina 2018, 20(4):58-62 | DOI: 10.26552/com.C.2018.4.58-62
This work presents results of strength analyses of a modified freight wagon bogie frame. It consists of two main parts. The first part is addressed to introduction of the structure of a freight wagon bogie frame. It is a modified frame structure, which reflects current requirements of modern railway transport means. The conditions for rail vehicles approval and the main load cases, which every bogie frame must meet for commissioning, are described. The next part deals with computer modelling and analyses of this bogie frame. Strength analyses were performed using the FE method and they were focused on the assessment of stresses in the frame structure....
Civil Engineering in Transport
Identification of Modal Frequencies From the Pre-Stressed Concrete Bridge Dynamic Response to Different Sources of Dynamic Excitation
Jozef Melcer, Jan Kortis, Lubos Daniel, Peter Fabo
Communications - Scientific Letters of the University of Zilina 2018, 20(4):63-68 | DOI: 10.26552/com.C.2018.4.63-68
The natural frequencies and mode shapes are unique characteristics of each mechanical structure. Their prediction is a crucial part of each dynamic experimental measurement. However, the proper identification of higher natural frequencies and mode shapes can be a problem, especially for big structures such as bridges. The reason is the need to excite the bridge in such a way that it responds in a free-vibrations mode shape. This paper describes three various sources of excitations, which are used to identify the modal characteristics of the pre-stressed concrete bridge. The impulse excitation, traffic load and ambient vibration are used and analyzed....
Critical Gaps at Unsignalized Intersections with Bending Right-of-Way
Andrea Kocianova, Eva Pitlova
Communications - Scientific Letters of the University of Zilina 2018, 20(4):69-75 | DOI: 10.26552/com.C.2018.4.69-75
The capacity calculation procedure for unsignalized intersections is based on the gap-acceptance theory in most of existing capacity regulations and it relies on one of the important parameters - critical gap. However, the capacity calculation procedure and values of critical gaps according to these regulations are valid only for intersections with standard right-of-way (major street leading straight). Nevertheless, in Slovakia, intersections with bending right-of-way (major street not leading straight, but bending) can be encountered. The specific mode of right-of-way results in different priority ranks of traffic movements (set by traffic rules of...
Safety and Security Engineering in Transport
The Quality and the Complete Evidence Securing during the Traffic Crime Scene Investigation and its Relevance for Evidence Completion during the Traffic Accidents
Peter Havaj
Communications - Scientific Letters of the University of Zilina 2018, 20(4):76-81 | DOI: 10.26552/com.C.2018.4.76-81
Main purpose of this paper is to point out the problems considering the modern scientific usage of methods, ways and approaches, including the crime investigation of traffic accidents-collisions. We want to show the basic need of experienced traffic crime detective, his/her deep knowledge of the whole issue - the process of the traffic accident perpetrating as a complex process with the direct impact on the traffic crime detective work, which could be used in the process of the clearance the case, the video-record output created by program PC CRASH as the virtual element of legal evidence, enabling deeper knowledge of the whole process.
Erratum
Errata: Communications - Scientific Letters of the University of Zilina, Vol. 20, No.2, 2018, "Application of a Priori and a Posteriori Estimate on Risk Assessment", pp. 56-61. The proper name of third author should be as follows: Witalis Pellowski.
Lenka Sivakova, Anna Zubkova, Witalis Pellowski
Communications - Scientific Letters of the University of Zilina 2018, 20(4):83 | DOI: 10.26552/com.C.2018.4.83
Errata: Communications - Scientific Letters of the University of Zilina, Vol. 20, No.2, 2018, "Application of a Priori and a Posteriori Estimate on Risk Assessment", pp. 56-61. The proper name of third author should be as follows:Witalis Pellowski.