Among the materials used for components subjected to abrasive wear, chromium cast iron, hardfaced layers, martensitic steels and Hadfield steel should be singled out. Each of these types of materials exhibits a different morphology of structure and strength properties. Hadfield steel, characterized by an austenitic microstructure, shows the ability to strengthen the subsurface layers by cold work, while maintaining a ductile core. Hardox steels belong to the group of low-alloy martensitic boron steels. However, it should be noted that increasing hardness does not always translate into low wear values due to a change in the nature of wear. In view of the above, the authors decided to subject selected Hardox steels and Hadfield cast steels in the post-operational condition to abrasive wear tests in the presence of loose abrasive. The study showed that Hardox Extreme steel exhibits the highest resistance to abrasive wear (value of the coefficient k_b is equal to 1.39). In the case of Hadfield steel, the recorded values are slightly lower (k_b = 1.32 and 1.33), while the above ratios remain higher compared to Hardox 600 and Hardox 500 steels. The main wear mechanism of high-manganese steels is microploughing, plastic deformation and breakouts of larger fragments of material. In the case of Hardox 450 and Hardox 500 steels, the predominant wear mechanisms are microploughing and breaking out of material fragments. As the hardness of the steel increases, the proportion of wear by microcutting and scratching predominates.

The porosity of rocks is an important parameter used in rock mechanics and underground mining. It affects the movement of fluids in the rock mass and the internal processes taking place (the ability to store water or gases), allowing us to characterize the type of rock and determine possible future applications. Conventional porosity testing methods (e.g., test drill cores in the laboratory) are complex and time-consuming. On the other hand, more modern technologies, such as computed tomography, are high-cost. In the presented study, a core sample with karst and porous structures inside was used. This core sample was poured with resin to reinforce the outer surfaces of the core and make it easier to cut with a rock saw. It was then cut into 3 mm thickness slices in preparation for the next step—the 3D optical scanning. Measurements were made with the ATOS CORE 500 optical scanner. Data processing was then performed in open-source software using popular and commonly used modeling methods. The 3D model of the core reconstructing the actual shape (with internal voids) and the standard model (without internal voids) were created. Based on these, the total porosity of the core was assessed. The presented solution ensures obtaining results with high accuracy at an adequate computational cost using cheap and easily available tools.

The aim of this study was to evaluate the effect of heat treatment, including solutionising and ageing in the temperature range of 20–250 °C, on the microstructural, mechanical, and tribological properties of the Al 7075 alloy. Microscopic analysis revealed that in the as-received condition and after natural ageing, the microstructure is characterised by the presence of elongated grains and a banded distribution of precipitates, whereas higher ageing temperatures lead to their coarsening and the initiation of recrystallisation processes. The highest hardness (189 HV) was obtained after ageing at 100 °C for 48 h, while further increases in temperature caused a systematic decrease in hardness—down to 85 HV at 250 °C for 4 h. Impact tests showed that in the as-received condition, the material reached a value of 7 J/cm², after natural ageing 15 J/cm², and the maximum (26 J/cm²) was achieved for samples aged at 250 °C for 4 h. Tribological tests conducted using the T-07 method confirmed the dependence of wear resistance on heat treatment parameters—the lowest relative abrasive wear resistance coefficient was observed after natural ageing (k_b = 0.860), and the highest after ageing at 250 °C for 4 h (k_b = 1.216). The results obtained indicate that moderate ageing conditions (100–150 °C) favour increased hardness, whereas higher temperatures (200–250 °C) lead to an improvement in impact strength and tribological resistance, which showed an inversely proportional relationship with hardness, contrary to Archard’s law.

In the face of increasing requirements for exhaust emission reduction and the search for alternative fuels, ammonia is being considered as a potential fuel component in compression-ignition engines. The aim of this study was to conduct preliminary research on the co-combustion process of ammonia with diesel fuel and to assess its impact on exhaust emissions and engine performance characteristics. In the first stage, measurements of ammonia concentration in the exhaust gases were carried out to determine its presence in the exhaust stream. Next, optimal engine operating points were determined for various fuel ratios, enabling a comparative analysis of the combustion of pure diesel fuel and its mixtures with ammonia. In the final phase, key exhaust emission components were measured. The results indicate both potential benefits and challenges associated with using ammonia as a fuel additive in diesel engines. The conducted research provides a basis for further analysis aimed at optimizing the ammonia co-combustion process to improve efficiency and reduce its environmental impact.

In the face of growing requirements for reducing exhaust emissions and the need to seek more ecological solutions in the transport sector, more and more attention is being paid to alternative fuels. This article examines the potential of using fuel mixtures containing bio-components, in particular alcohols and Sustainable Aviation Fuel (SAF), as a substitute for conventional fuels. The research focuses on two key aspects: composition of the fuel mixture and exhaust emissions. The research results aim to determine whether the proposed alternative fuel mixture can be an effective and more ecological alternative to conventional fuels, while maintaining appropriate operating properties. The results of the work can be a valuable contribution to the development of sustainable fuel technologies and help reduce the negative impact of transport on the environment.