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The article is concerned with comparison of the three transportation experiments using the two vehicle types (Tatra 810 and Tatra 815 MK IV) on two road types (higher and lower quality). From the transportation experiments, three datasets were obtained to be compared mutually and to the normatively determined values of acceleration coefficients, as well. In the article, the calculation of the probability of excess and double excess of the normatively determined limits is also included. For the purpose of the comparison, statistical tests of equality and three different parameters are employed. Statistically significant differences between the datasets are the outcome of the article, i.e. there are statistically significant differences between the vehicles and roads tested with regard to generated shocks. The results are primarily usable in the cargo securing system optimisation in road transportation and transport safety.

A model for an equivalent electrical circuit designed for a ferrite (3C90) inductor usually used in power converters excited by a non-sinusoidal current appropriate for use in power electronics is proposed. This study, based on 3D finite element analysis, leads to significant precision advantages over 2D analysis for non-symmetric inductors. The frequency range of the analysis for the toroidal core was between 15 kHz and 1 GHz, with different levels of excitation in non-saturation and saturation status focusing on the power loss.

The aim of this paper was to define the important market risk sources in the transport small and medium-sized enterprises segment. A part of this aim is to find out how entrepreneurs evaluate these sources, and quantify the differences in their evaluation based on the entrepreneur's characteristics, such as nationality, age, gender and others. The questionnaire was completed by 122 enterprises from Slovakia, Poland, the Czech Republic and Serbia. Statistical tools such as pivot tables, percentages and goodness-of-fit tests were applied to verify the formulated hypotheses. The most important source of market risk is a strong competition in the line of business. The obtained education of entrepreneurs is statistically significant characteristics for the evaluation of the market risk sources in selected transport enterprises. The findings are important for state institutions and their support systems in the transport SMEs segment.

This article is devoted to development of a method for calculating the parameters of an asynchronous motor of an electric locomotive with asymmetrical windings of stator and rotor. A method for determining self and mutual inductances of the stator and rotor phases of an asynchronous motor with asymmetric windings and their relations to mechanical variables is proposed. It is based on comparing two equations of stored magnetic energy, one equation calculated through induction, magnetic field strength and geometrical dimensions and another equation calculated through the parameters of the motor circuits. It is shown that the obtained solutions correspond to the previously existing methods, but they give the additional possibilities in mathematical modeling. The proposed technical solution allows higher accuracy developing of a mathematical model of a drive with an asynchronous motor having asymmetrical stator and rotor windings for studying dynamic processes during the operation of the specified drive, in particular, the drive of auxiliary machines for electric locomotive, where an asynchronous motor with asymmetrical stator windings is used as a phase release.

The article deals with an optimization procedure of roller elements geometry with regard to durability of spherical roller bearings. The aim of the article is to examine the impact of change of the roller elements inner geometry on durability and reliability of spherical roller bearings; the contact strain along a spherical roller by means of the Finite Element Method at contact points of components of a spherical roller bearing by means of designed 3D parametric models. The most appropriate shape of roller elements inner geometry of a bearing from the standpoint of calculated durability was determined based on results of the contact analyses.

System identification is a scientific field with a wide range of applications, including transport and transportation systems. Automotive industry has a growing trend of power converters implementation. In addition, intelligence of converters is developing. Thus, the power electronics and autotronics are application areas where identification can also be applied. Since buck (step-down), boost (step-up) and buck-boost are the most common topologies of the converters in automobiles, this article aims to demonstrate possibilities of using the identification procedure on the synchronous buck converter. The objective is to obtain a parametric model that could be further useful in analysis and other work with the converter.

This study publishes results of tests with regard to determination of the aircraft positioning accuracy by means of the GPS navigation in aviation. The research exploits the mathematical model of the linear combination "IonosphereFree" in order to designate the coordinates of an aircraft. The research uses the actual GPS code observations, recorded by a satellite receiver mounted in the Cessna 172, at the time of the experiment for the EPDE military aerodrome in Dęblin. The computations of the position of the Cessna 172 aircraft for the linear combination "Ionosphere-Free" were made in the APS Toolbox v.1.0.0. programme. Within evaluation of accuracy of the GPS positioning in aviation, the determined coordinates of the aircraft Cessna 172 from the APS programme were compared to an accurate reference position from the solution derived by the PPP measurement technique. In the research, the authors obtained an average positioning accuracy of approximately 5 m in the geocentric XYZ coordinates and approximately 4 m in the ellipsoidal BLh coordinates. In addition, the 3D-error parameter is lower than 7 m for the XYZ geocentric coordinates.

In this paper, a new approach is introduced upgrading the complex object recognizing monitoring system up to the image processing system capable of operating both in the visible and the infrared wavelength ranges. For this purpose, both new algorithmic software and user interface are provided that require from the operator neither special knowledge, nor specific competencies in the fields of object detection, tracking and recognition, while allowing determining the thermal imager parameters necessary for constructing a high-quality image of an object. There are formulated the conditions required for obtaining such image that, by its quality, would make the satisfactory detection of the desired object possible. By means of the conducted tests, it is demonstrated that the application of the proposed mathematical and algorithmic support of the complex monitoring and control system provides the solution for the problem of the highly accurate individual recognition.

The paper presents a fire service determined picture of road safety in Poland in its operational (non-system and system) dimensions. It focuses on the road risk assessment, using data related to interventions conducted in 2015-2019 by entities of the State Firefighting Rescue System. The database of the Main Headquarters of the State Fire Service in Poland is adopted and 661,775 emergency road interventions are taken into account.The results state general framework for procedures, resource allocation and training for fire services. The framework is determined by the riskiest kinds of events on the Polish roads. It refers to micro scale (in relation to operational procedures, tactics and strategies, allocation of equipment and training programs) and macro scale (regarding to emergency system, central-planned equipment procurements and training framework).

Unmanned Aerial Vehicles (UAVs) are still an interesting and current research topic in photogrammetry. An important issue in this area is determining the elements of exterior orientation of image data acquired at low altitudes. The article presents selected mathematical methods (TGC, TIC, TAD) of estimating elements of exterior orientation for image data obtained at low altitudes. The measurement data for the experimental test were recorded by the Unmanned Aerial Vehicle platform Trimble UX-5. In the framework of the test photogrammetric flight, the authors obtained 506 images and navigation data specifying the position and orientation of the Unmanned Aerial Vehicle. As a result of the research, it is proven possible to show the usefulness of the mathematical models (TGC, TIC, TAD) in estimation of elements of exterior orientation.

The aim of the paper is to inform about the possibilities of using a fuzzy logical deduction in security practice. The fuzzy logic deduction allows to record the management experience in IF - THEN rules and does not require a precise description of the parameters of the controlled function. This property is an important asset for risk assessment in an incompletely defined environment. The application of the method is demonstrated in the security risk assessment of the physical protection of the national railway with a focus on the corridor railway lines and with regard to the future construction of high-speed railway lines in the Czech Republic. At present, it is a generally accepted fact that securing basic transport functions is a prerequisite for successful crisis management. These functions can be specified as road and rail negotiability.

The article describes the method of estimating the parameters of transport flows using the two-fluid mathematical model of Herman-Prigogine and developed and based on the proposed method of estimating the parameters of the system on the basis of passive processing of navigation data on the movement of vehicles. The efficiency of the proposed algorithms, mathematical models for estimating the parameters of road traffic flow and system as a whole was confirmed during its testing using a set of tracks on the main highways of Commonwealth of Independent States.

Paper presents diagnostic analysis of automotive ignition system for various working and adverse conditions in laboratory. Description and importance of basic diagnostics of automotive ignition system are examined in the first part of the paper. In the second the focus is placed on the basic principles and solution of the spark plug model. The test laboratory device is proposed in the following and the specialized measurements were executed by the proposed measurement system. The faults were simulated by application of oil and gasoline between the electrodes and failing by the driver to make the ignition contact on the spark plug.

In this article, the electrical properties, as well as the economic aspects of the modular and non-modular solution of the DC-DC photovoltaic converter for DC microgrid subsystem, are described. Principally a theoretical overview of the circuit configuration for the selected DC-DC stage of the DC microgrid system is shown. It is dealt with the comparison of the one non-modular high - voltage SiC-based dual - interleaved converter operating at the low switching frequency and with modular low voltage GaN-based DC-DC converters operating at high switching frequencies. The main focus is given to the research of the dependency that arises from the different module count, overall efficiency, costs, and power density (system volume). High efficiency, reduced overall volume, and maximum power density are important factors within modern and progressive solar systems. It is assumed that with the increase of switching frequency within the modular system the volume reduction of the passive components will be highly demanded, thus PCB dimensions and overall volume can be reduced. This dependency is investigated, while the total volume of the non-modular system is a unit of the measure. For these purposes, the design of variant solution was done, and consequently mutually compared in the way of simulations and experimental measurements.

This paper presents results of the experimental research aimed at fire and smoke properties of rolling stock coating system. The overriding research task was to meet current European requirements in the field of fire properties with maintaining the desired performance parameters, such as protective and decorative properties. The research determined parameters such as flame spreading over the surface and heat emission of coating system prepared on steel substrate. Research was carried out to find the optimum thickness of intumescent layer. The tests have shown the effectiveness of use of a protective paint that allows meeting the requirements in the field of fire safety.

Influence of boundary conditions (i.e. mounting type of shafts ends) on spectral and modal properties is studied in this paper. Cases with joints at both ends and with joint at one end and fixed end are described in detail. The vibration problem of rotating shaft is generalized to problem of vibration of the shaft in the rotating plane. The problem is illustrated on testing models. The real mounting type of shafts is presented.

A phosphating process modified for a high-strength low-alloy (HSLA) steel was performed at various temperatures and influence on the surface properties of the Domex steel covered by manganese phosphate (MnP) was investigated by electrochemical corrosion tests supported by a photo documentation performed by the SEM. Corrosion measurements were performed in 0.1M NaCl solution at 22±2 °C using electrochemical impedance spectroscopy and potentio-dynamic polarisation in order to obtain thermodynamic and kinetic corrosion characteristics and individual elements of equivalent circuits. It is that a temperature of the phosphating process has a very significant effect on protection properties of the created manganese phosphate coating on the Domex steel and needs to be strictly monitored. According to results of corrosion testing and surface morphology observations, the optimal temperature for the phosphating process on the tested Domex steel was chosen.

This study defines criteria and sub-criteria for evaluation of the transport technology for carriage of passengers by railway and road transport. The main criteria are divided into four groups: business, environmental, social and technological, named BEST analysis. Twenty-four sub-criteria have been examined. The method of multi-criteria analysis Decision Making Trial and Evaluation Laboratory (DEMATEL) has been applied to analyse importance and the relations between the criteria. Results show that e criteria of the great importance are business group (29.47%) and technological group (27.49%). The sub-criteria: transport costs for fuel (7.83%); ticket price (8.29%); time travel (6.99%); directness (6.47%) and direct operating costs (6.30%) are the most important. The defined criteria and subcriteria can be applied for evaluation, comparison and selection the transportation variant.

The article discusses handicaps in predicting values of rotation angles with regard to Heading, Pitch and Roll for an Unmanned Aerial Vehicle. Within the simulation of the rotation angle values, the linear, polynomial and logarithmic methods were used. The programme source code was written in the numerical editor Scilab 5.4.1. The source data for investigation were recorded by a measuring device Trimble UX-5. The article provides results of comparing the real values of Heading, Pitch and Roll rotation angles to findings obtained from the prediction methods. Based on the conducted research, it was found that the largest value of standard deviation parameter in prediction of the rotation angles is for the angle of Heading, as it equals approximately 5o, whereas the smallest ones are for the Roll and Pitch angles, equalling less than 1.4o.

Alarm systems are used to warn passengers and employees in railway stations, airports, logistics facilities and administrative buildings of hazards; in this way, they are instructed to rescue themselves. A large online survey conducted in Germany in 2018 has shown that often sounding the alarm does not have the desired effect. The research presented in this article investigates dependence of an alarm effectiveness on type of building, user profile and type of the alarm system.
In this paper, general and building-specific measures, using which the effective sounding of the alarm and optimal behaviour of the building users in the case of danger can be achieved, are presented.

The classical solution for critical stresses in the problem of stability of a circular longitudinally compressed cylindrical shell consists of two terms, reflecting the ability of the shell to resist buckling due to bending and membrane deformations. However, with usual boundary conditions the classical solution appears only with the absence of the Poisson expansion of a shell. With a non-zero Poisson's ratio, an axisymmetric edge effect presents. It reduces the critical load and causes the initial arrangement of its own forms to change as the load increases.

The paper deals with the issue of GNSS interference and its subsequent impact on airport approach procedures. It discusses the problem of GNSS signal interference and interference identification on a practical example of a small regional airport in Zilina, located close to the highway, through research aimed at its identification, a proposal for the location of a monitoring station and subsequent practical verification. The paper seeks to analyse and provide recommendations for enhancing safety and reliability in GNSS approaches. Given the need to develop the air transport, it is important to ensure the safety and continuity of service provision at small regional airports. The GNSS approach at airports with insufficiently equipped navigation infrastructure seems to be one of the most suitable. Introduction of the GNSS interference monitoring in the final instrument approach phase would increase the safety and reliability of the flight.

For many years issues of the free provision of transport services, including urban public transport, were outside the main trends of transport economics considerations. However, nowadays, the discussion is ongoing related to usefulness and limitations of the free urban public transport implementation. Protection of the city environment, reduction of personal cars traffic, and increased accessibility and mobility in cities are given as premises for such solution introduction. However, assessments of introduced solutions may not necessarily confirm the assumptions made. Financial problems and those in provision of services - characteristic of goods and services provided for free - add to that. The paper has undertaken the issue related to premises and limitations related to introduction of the fare free urban public transport in regard to the pursuit of effectiveness in the public management.

This paper presents the draft methodology to be applied for evaluating the financial health of airlines. In the introductory part, specific attributes, regarding the individual types of airlines, are described. Subsequent parts of the manuscript outline advantages and disadvantages to measure airlines performance when implementing financial indicators, as well as a general procedure to evaluate the financial situation of a company operating in the aviation industry. The most important part of the paper includes the proposal of the specific functional system to evaluate the economic performance of airlines. Financial evaluation itself (evaluation of financial indicators of the enterprise's economic performance) is performed through a particular case study when comparing several existing airlines.

The costs of each company on the market are an essential component of financial decision making, not only on the price of the goods and services provided, but also about the business efficiency. In business, services have a significant impact on pricing, but also for deciding on the realization of performances. Costs structure is composed of fixed and variable costs. Changing the costs structure creates assumptions for other decisions, as well as the pricing of the entrepreneur. The goal of this article was to identify, whether there is a change in time of the costs structure.

Premature failure or damage of parts and components of the oil and gas well piping, as well as pipelines for transport of oil and gas, are generally caused by the simultaneous influence of a large number of technological, metallurgical, structural and exploitation factors. Therefore, the convenient structural solutions, which provide the mechanical safety of parts and integrity of structures, can be realized only through total comprehension of their behavior in various operation regimes. Importance of technical diagnostics for monitoring and state analysis of welded pipes/pipelines in oil industry is considered in this paper. An analysis of causes of the welded pipes failures in exploitation has been performed through use of the fault tree analysis. Based on the suggested structure of a database, regarding the causes of failure, possibilities are presented to set measures for prevention of damage and failure of welded pipes/pipelines and for extension of their service life. A suggestion for improvement of the organizational scheme for monitoring the state and maintenance of welded pipes/pipelines during the exploitation has been made, as well.

In the current digital era, information is a basis of some systems. In the area of information, great emphasis is also placed on its security and possibilities of use. The basis of the alarm transmission system is information about the protected object, which is transmitted to the remote center of the alarm transmission system. Operators of alarm transmission system centers should be obliged to carry out regular testing of the availability of individual transmission networks. At present, there is a trend that those tests are carried out by telephone calls between the two technicians and the time of transmission of information is measured utilizing a stopwatch. To automate this process, a test facility has been created that can simulate and record the intrusion of a protected object. Initial experimental tests have ascertained whether it is possible, with the test equipment, to generate the data necessary to assess the reliability of alarm transmission systems.

In this paper the authors introduce results from the field of the fatigue safety of selected steels in the region of ultra - high number of loading cycles. The fatigue tests were carried out at high frequency tension - compression loading (f = 20 kHz, T = 20 ± 5°, R = -1) in the region from N = 106 to N = 109 cycles. The fatigue safety coefficients were calculated by four methods (Goodman, Gerber, ASME elliptic and Soderberg). The percentage reduction of the fatigue safety coefficients (N = 109 vs. N = 106 cycles) was at Goodman, 7.99 / 10.83 %, Gerber, 5.27 / 8.26 %, ASME, 1.89 / 6.42 % and Soderberg, 6.51 / 10.25 %.

The aim of this research was to conduct the comparative traction tests for T-170M1.03-55 tractor with a flat and elliptical rim. Structurally rational geometry of the crawler's support surface for tractors with semi-rigid suspension is realized by placing the support rollers at different heights relative to the cart. The results of traction tests showed that elliptical track rim has increased the maximum traction power by 10.4%, conditional traction propulsive efficiency coefficient to 7.43% and the specific traction effort by 8%. The increase in indicators is provided by a lower rolling resistance of a tractor with an elliptical rim. Reduction of the resistance power to rolling of the tractor with an ellipse track rim occurs due to alignment of support rollers vertical load and reduction of resistance to rollers movement on internal contours of tracks and in hinges of track chain links. The results of the research indicate a significant improvement in traction performance of T-170M1.03.55 tractors with elliptical track-chain rim.

Currently, there is progressive use of fire protection systems that use the high-pressure water mist. The extinguishing effect of water mist on flammable liquids is not sufficiently elucidated. Therefore, experiments were designed to gain new knowledge about the mechanism of the high-pressure water mist extinguishing.As a source of the pool fire, gasoline, kerosene, diesel and ethanol were used. Flammable liquids were stored in a circular steel container with a diameter of 165mm and a depth of 12mm. The container was placed in an enclosed room of 2.7 x 2.7m x 3m. In the experiment, the time to extinguish flammable liquids was measured using nozzles of different spray characteristics of the water mist. The nozzles with orifice 400 µm, 800 µm and 1000 µm were used at a constant pressure of 70 bar.