For a few years attempts have been made to introduce electric-powered buses to public transportation system. In order to solve this problem rationally, in dependence of local public transport system conditions, models of technical, organizational, economic and ecological links enabling optimal choice of type of propulsion for particular bus line is developed. Technical solutions to enable fully electric busses should be evaluated whether they reflect the prerequisites and requirements of the participating public transport companies. The paper presents a method for evaluating transport system in accordance with the principles of cost-benefit analysis that allows to answer the questions related to the cost-effectiveness of the use of electric drive buses in urban public transport. The model can be used to analyse and design the services of urban public transport in terms of costs generated by the bus fleet equipped with various types of drive. The article presents procedures used to determine the costs used in the method of evaluation of the proposed solutions. The ultimate goal is to find the best technical solution for local public transport companies depending on their real input data (timetable, vehicle operation plan, etc.), which in most cases may mean minimising economic effects, like investment and operational costs

In this paper, the application of nanosensors based on epoxy resin and antimony sulphoiodide nanocomposite for traffic monitoring is presented for the first time. The physical principles of the traffic measurements via the piezoelectric effect have been explained. The excitation mechanism of the piezoelectric charges in a nanocomposite by a moving vehicle is also discussed. The paper demonstrates the sensor’s capability for speed measurement and investigates the influence of vehicle speed on the sensor output voltage and generated energy. It is emphasized that speed measurement should be based on the time interval between voltage peaks generated by vehicle wheels rather than voltage amplitude. The peak-to-peak voltage, energy density, as well as instantaneous and average power densities from the unit volume of the nanocomposite generated per unit of vehicle load moving at a unit speed, are calculated. The paper also outlines future directions for the development of these sensors, intending to enhance energy harvesting efficiency.

This paper presents the results of numerical experiments on fire development and the backdraft phenomenon. The numerical model of fire development built with the use of Ansys Fluent was then validated based on literature data taken from real fire experiments. Some theoretical foundations of airflow and combustion modelling were added. Some features of the numerical model, which allowed for its high accuracy to be achieved, were widely discussed. Since large buoyancy forces were involved, to reproduce the decrease of the atmospheric pressure with height, a variable static pressure was applied using UDF (user-defined function).The results showed good accordance taking into account both the temperature profiles and the distribution of the airflow velocity. Once the model was validated, the research was extended to examine the backdraft phenomenon. The results revealed characteristic phases of the phenomenon and the occurrence of the gravity current as well, which were reported by empirical experiments.

The results of the tribological studies on the lubrication efficiency of greases evaluated based on tribological tests performed at varying pressure p and rubbing speed v are presented. For the efficiency criterion, the volume of wear VF(d) obtained from the regression equations of wear was adopted (wear F (d) = f (F, v)). Six different lubricants were tested; two of them were commercial greases, and four of them were compositions based on them, including conventional solid greases (PTFE, tin, copper, and boron nitride). The experiment was carried out on a four-ball extreme pressure tester according to a rotatable design on five levels. For each of the selected lubricants, a regression function was developed that defined wear as a function of rubbing speed and load. The volume of the obtained wear VF(d) was calculated and relevant conclusions were drawn.