Scientific Journal of Silesian University of Technology. Series Transport

9

Authors: Bartosz BOCIĄGA

This paper discusses the environmental characteristics of assets of the public transport systems in Górnośląsko-Dąbrowska Metropolis. The public transport is served by a number of companies. This poses the problem of integrating their behaviour in a coherent manner for environment protection. The Metropolis includes regions highly populated with good road networks as well as small localities which generates small transport demands. The transport potential is assessed and categorised in relation to its impact on the environment. The volume of emission of pollutants and the severity of their presence in the environment are summarised. Conditions of the functioning of the constituents of the systems were analysed, accounting for their contribution to pollution as well as health hazards cases.

9

Authors: Borys VINOGRADOV

The purpose of this study was to assess the effectiveness of flexible air-spring systems operating in parallel to share the total load, taking into account installation and in-operation errors. This study presented experimental and calculated characteristics of the air spring flexibility and its dependence on the polytropic index and additional volume. It considered patterns of load distribution between the air springs when they are operating in parallel to share the total load for the case when the air springs were used as the supporting elements for various machines and units, and between transmission lines containing flexible couplings, where air springs were installed as flexible elements.

10

Authors: Tomasz WĘGRZYN, Adam JUREK, Łukasz WSZOŁEK, Zbigniew STANIK

The developing automotive industry has prompted an increase in the demand for new welding technologies in civil engineering and transport that reduce the mass of mobile platforms mounted on vehicles and increase their operational range at the same time. The AHSS steels are the materials most commonly adapted for the production of motor vehicles due to their high tensile strength. Nonetheless, the joints created with their use are less strong from the native material. This article examined whether the application of micro-jet cooling would alter the mechanical properties of the welds. Based on the performed tests, joints with better quality that passed positively in the hardness and tensile strength evaluations were obtained. The presented research proves that the use of additional elements in the welding process significantly affects the quality of the obtained welds and brings satisfactory results with a greater repeatability than before.

11

Authors: Kamil KRASUSKI, Małgorzata KIRSCHENSTEIN

This paper presents research results on the determination of meteorological parameters utilising the GPS satellite technique. The meteorological parameters were designated using Standard Atmosphere (SA) and UNB3m empirical models. The research experiment was realised during a flight test at the Dęblin military aerodrome. In the flight test, the Cessna 172 plane was used. The values of meteorological parameters (for example, temperature, pressure and relative humidity) from the troposphere empirical models were presented and compared in the paper. In addition, the values of the meteorological parameters were estimated at flight attitude. The range of the flight attitude was between 150 and 700 m. The precision position of the aircraft in vertical frame was determinated using the RTK-OTF differential technique. The mean difference of temperature between the SA and UNB3m models is equal to -5.7°C with the RMS bias approximately 0.2°C. The mean difference of pressure between the SA and UNB3m models equals -1.0 hPa with the RMS bias of approximately 0.3 hPa. The mean difference of relative humidity between the SA and UNB3m models equals 25.5%, with the RMS bias approximately 0.6%. On paper, the values of meteorological data from the SA and UNB3m models were compared with true results interpolated from SYNOP message. In research, the three SYNOP stations, that is, Kozienice, Deblin/Irena and Lublin Radawiec were used for interpolation of the real meteorological data. The difference between empirical and interpolated meteorological data were presented in this paper. The accuracy of the designation of temperature is better in the SA model rather than the UNB3m model. The accuracy of the designation of pressure was relatively low in both models, SA and UNB3m. On the other hand, the accuracy of the designation of relative humidity was better in the UNB3m model than the SA model.

11

Authors: Elżbieta MACIOSZEK, Nan KANG

The assessment of psychotechnical parameters (that is, critical gaps and follow-up times) of vehicle drivers at roundabout Hitachi Taga, Ibaraki Prefecture in Japan was presented in this paper. The basis for this assessment were empirical data from measurements in the field, made in two different years. The first field measurement took place two years after the construction of the roundabout in 2014, and the second one in 2019. The results comparison of 2014 and 2019 was aimed at assessing possible changes in the psychotechnical parameters in time. This assessment was carried out as one of the element of the project titled “Analysis of the applicability of the author's method of roundabouts entry capacity calculation developed for the conditions prevailing in Poland to the conditions prevailing at roundabouts in Tokyo (Japan) and in the Tokyo surroundings”, financed by the Polish National Agency for Academic Exchange.

12

Authors: Olga SCHERBINA, Oleksii DROZHZHYN, Oleksander YATSENKO, Oleksander SHYBAEV

The society’s main trend for globalisation requires the restructuring of the global transport system as a whole. The ‘Dnieper region’ is no exception, as it needs changes in its practice of organising and managing its process of cargo delivery in accordance with the current trends. This paper considered the main solution directions of this problem in the aspect of ‘container on barge system’ transportation in accordance with the potential of the region. Based on international experience, the competitiveness of the container on barge system can be ensured by applying the different forms of cooperation between the business-players. In the case of horizontal cooperation, it’s raising the problem of distribution of structural elements of the container on barge system during the container-flows adoption. So, the paper proposed the mathematical decision to maximise the use of the linear ship's characteristics by the barge’s loading capacity and by the tug’s engine power.

15

Authors: Jaroslav HOMIŠIN

A change in torsional stiffness of pneumatic tuners can be achieved by changing the pressure of the gaseous medium in the course of the mechanical systems' operation or while idle. Based on this statement, we tuned mechanical systems with torsional vibration when they are either idle or when they reach stable condition during operation. The principle of tuning mechanical systems with torsional vibration during operation when their condition is stable lies in the appropriate adaptation of basic dynamic properties (dynamic torsional stiffness and damping factor) of the pneumatic tuner to the dynamics of the system. This was achieved with a control system that helps create a closed control feedback loop. In this way, we can continuously change, that is, adapt the dynamic properties of the pneumatic tuner to the dynamics of the mechanical system so that no dangerous torsional vibrations occur while the system is in operation mode.

15

Authors: Bożena SZCZUCKA-LASOTA, Joanna KAMIŃSKA, Iwona KRZYŻEWSKA

In recent years, the development of IT systems for fleet monitoring was observed. Tire pressure monitoring systems are constantly improved. Decreased values in tire pressure can cause deformation of tires. Monitoring of tire pressure is an important function in oversized transport trucks. Tire pressure and rolling resistant influence fuel consumption. The purpose of this paper was to determine the impact of tire pressure on fuel consumption in a fleet of trucks with tire pressure monitoring system installed and to determine the impact of other factors that may affect fuel consumption, such as the vehicle weight, brake usage and cruise control usage. The results of the research were developed using a multiple regression model describing the above dependence.