The article describes the design and optimization of operation of an electric bus? powered? by? the? hydrogen? fuel? cells.? At? the? beginning,? an? approach? to? design? of? a? 12-meter? urban? bus,? powered? by? hydrogen,? is? presented,? a...

Contemporary research on electric buses focuses mainly on the following issues: energy efficiency, range and transport costs, and traction battery technology. However, little research has been conducted on operational reliability. This article presents a comparative assessment of the reliability of electric buses in relation to combustion engine buses. The research was conducted under real conditions in the city of Lublin, Poland. The reliability functions of buses and their structural components were determined based on the Weibull distribution. It was shown that electric buses have a shorter distance between failures than combustion engine buses of analogous capacity. The statistical significance of the differences in reliability between electric and combustion engine buses was verified. The suitability of the Weibull model as a model of bus reliability in comparative studies was verified. The results of the research can be used to monitor current sustainable public transport development programs and to improve bus diagnostic and maintenance systems in transport companies.

This study deals with the assessment of the progress of the electromobility programme with regard to the technical availability of public transport buses. The aim of this study was to conduct a comparative assessment of the availability of electric buses in relation to diesel buses (of analogous capacity). The study was carried out in real operating conditions using the example of Lublin city. Over a period of 33 months, the availability of electric buses and diesel buses was tested in a sample of 18 vehicles for each type of bus. Availability indices were compared using the method of variance analysis. It was found that electric buses had a higher level of availability and no trend during the study period. The applied research method can be used in operational practice to monitor the risks associated with vehicle failure rates and the continuity of fleet operations.

This study presents the application of the Bayesian method to estimate the probability of critical marginal leakage in dental restorations. Aim of the study was to evaluate the effectiveness of the Bayesian method in estimating the probability of leakage associated with gap in the subsurface layers of composite restorations, based on observations of their surfaces. The study, involving the construction of a Bayesian network model and probabilistic inference, was based on the results of experimental research. These results were used to verify the a priori and a posteriori probabilities of damage to the tooth-restoration system in three zones of the tooth’s anatomical structure and across four load level intervals; using a Bayesian classifier, the study demonstrated the potential for diagnosing critical subsurface leaks. The results obtained show that surface fissure parameters can support the probabilistic diagnosis of leakage throughout the entire volume of the restorative filling, thereby assisting in clinical decision-making regarding the replacement of damage fillings

This study presents an experimental evaluation of operational wear in Djp 100 trolleybus contact wires used in the city of Lublin (Poland). The objective was to determine quantitative geometric and mechanical indicators of wear and to propose empirically based replacement criteria. New and long-service wires were examined using 3D scanning, optical profilometry, nanoindentation, and tensile testing. The results show significant changes in the cross-sectional geometry and mechanical performance: the maximum local profile deviation reached ≈2.5 mm, the average cross-sectional area decreased by ≈17%, and the moment of inertia $J_x$ was reduced by ≈30% (from ≈878 mm⁴ to ≈610 mm⁴). Tensile tests revealed a drop in breaking force from ≈37 kN (new wire) to ≈27 kN (used wire). Surface roughness Sa decreased approximately threefold, while nanoindentation showed local near-surface strengthening, with hardness and elastic modulus increasing up to twofold in worn zones. Based on these quantitative changes, combined geometric–mechanical wear indicators were formulated and used to derive practical replacement thresholds for trolleybus contact wires. These findings demonstrate that integrating cross-sectional wear, loss of load-bearing capacity, and local surface property changes provides a consistent and technically justified foundation for maintenance decisions in overhead contact line systems.

LETS (Lung Electrical Tomography System) is an innovative medical system enabling comprehensive heart and lung function monitoring. It utilizes advanced techniques such as electrical impedance tomography (EIT), body surface potential mapping (BSPM), and electrical capacitance tomography (ECT) to provide accurate information about physiological parameters. The LETS system allows one-time examinations and continuous monitoring 24 hours a day. Remotely measuring and monitoring parameters such as the electrical activity of the heart muscle, blood flow, blood pressure, pulse, and lung aeration enables rapid identification and intervention in case of abnormalities. The system also allows for the detection of cardiac arrhythmias and other heart disorders, as well as the assessment of lung respiratory capacity and optimization of ventilation strategies. However, it's important to note that the LETS system has some limitations. For example, it may not be suitable for patients with certain pacemakers or other implanted devices. Overall, LETS represents a breakthrough in medical imaging, opening up new possibilities in diagnosing and monitoring heart and lung diseases. Its integration may contribute to improving patient care and increasing the effectiveness of medical interventions.