This study discusses a quantitative fatigue evaluation of polymer–ceramic composites for dental restorations, i.e., commercial (Filtek Z550) and experimental Ex-nano (G), Ex-flow (G). Their evaluation is based on the following descriptors: mechanical strength, elastic modulus and strain work to fracture. Supposed to reflect factors of environmental degradation conditions, thermal fatigue was simulated with a special computer-controlled device performing algorithms of thermocycling. The specimens intended for the strength test underwent 10⁴ hydro-thermal fatigue cycles. This procedure of thermocycling was preceded by aging, which meant immersing the specimens in artificial saliva at 37 °C for 30 days. The strength tests after aging only and after aging and thermocycles were performed in line with the three-point flexural strength (TFS) test, specified in ISO 4049, and the biaxial flexural strength (BFS) test, specifically piston-on-three-ball in accordance with ISO 6872. Based on the results, it can be stated that composites with higher volume content of inorganic particles after aging only show higher strength than materials with lower filler particle content. For example, the average flexural bending strength of the Ex-flow (G) composite was about 45% lower than the value obtained for the Ex-nano (G) material. The residual strength after thermocycles is significantly lower for the experimental composites, whereas a smaller decrease in strength is recorded for the commercial composites. Decreases in strength were about 4% (Filtek Z550), 43% (Ex-nano (G)), and 29% (Ex-flow (G)) for the BFS test; and about 17% (Filtek Z550), 55% (Ex-nano (G)), 60% (Ex-flow (G)) for the TFS test. The elastic modulus of the experimental composites after only aging is higher (about 42%) than that of the commercial composite, but the elastic modulus of the commercial composite increases significantly after thermocycling. A descriptor known as strain work to fracture turns out to be a good descriptor for evaluating the hydro-thermal fatigue of the tested polymer–ceramic composites.

The paper presents the results of the research into the impact of impregnation of wood on its bending strength and elastic modulus under normal conditions and after thermal treatment and investigates its structural reliability. Pinewood, non-impregnated and pressure impregnated with a solution with SiO₂ nanoparticles, was used in this research. The use of nanoparticles decreases the flammability of timber among others. Some of the tested samples were treated at 250 °C. This temperature corresponds to the boundary of the self-ignition of wood. This elevated temperature was assumed to be reached by a given speed of heating within 10 min, and then the samples were stored in these conditions for 10 and 20 min. The tests demonstrate that the bending strength of the impregnated wood was slightly improved, the impregnation did not impact the elastic modulus of the material in all such conditions, and the residual strength decreased less for the wood impregnated after being exposed to the elevated temperatures. The reliability analysis proves a positive effect of impregnation with a solution with SiO₂ on the durability of wood, both after being exposed to normal and elevated temperatures. The distribution of the failure rates indicates a more intensive degradation of non-impregnated wood. The distribution of the survival function demonstrates a more probable non-destruction of impregnated wood after elevated temperature conditions.

This article presents comparative tests of contact strength and tribological wear resistance of polymer sliding materials of the polyamide group. The aim of this work was to study Shore hardness, indentation hardness, modulus, creep, relaxation, Martens hardness and sliding wear resistance of two commercial materials. One of these materials was produced with the recycling process in mind. Abrasion tests were performed against a stainless-steel ball (100CRr6) on a normal load of 5 N for 23,830 friction cycles. The samples were tested under dry friction conditions and taking into account the hydrothermal factor, the presence of which was assumed in the anticipated operating conditions. It was distilled water at a temperature of 50 °C. The volumetric wear of the samples under various environmental conditions was assessed and related to the mechanical properties, in particular, Shore hardness. This mechanical size, which characterizes the surface, was considered the most frequently used by engineers selecting polymeric materials for tribological applications in industry. The Shore hardness of both materials was similar, which may indicate similar tribological performance properties. However, research and analysis indicate the need to use measures that directly correspond to tribological wear. The friction and wear of both materials varied. The coefficient of friction in hydrothermal conditions was lower and the wear was higher than in the dry friction test. It seems that it was not hardness that determined the suitability in the anticipated operating conditions, but the ability to form a sliding layer on the friction surface. The properties of the material that has been envisaged as a replacement may be appropriate for the intended uses.

The article presents an algorithm for selecting an electric vehicle for your photovoltaic system. Generating electricity by distributed photovoltaic systems is a very visible trend across Europe. Individual and institutional owners are looking for opportunities to save large amounts of money...

Crystallization is a fundamental unit operation in chemical, pharmaceutical, and energy industries, where strict control of crystal size distribution (CSD) is essential for ensuring product quality and process efficiency. However, the nonlinear dynamics of crystallization and the absence of explicit functional relationships between process variables make effective control a significant challenge. This study proposes a hybrid approach that integrates process tomography with deep reinforcement learning (RL) for adaptive crystallization control. A dedicated hybrid tomographic system, combining Electrical Impedance Tomography (EIT) and Ultrasound Tomography (UST), was developed to provide complementary real-time spatial information, while a ResNet neural network enabled accurate image reconstruction. These data were used as input to a reinforcement learning agent operating in a Simulink-based simulation environment, where temperature was selected as the primary controlled variable. To evaluate the applicability of RL in this context, four representative algorithms: Actor–Critic, Asynchronous Advantage Actor–Critic, Proximal Policy Optimization (PPO), and Trust Region Policy Optimization, were implemented and compared. The results demonstrate that PPO achieved the most stable and effective performance, ensuring improved control of CSD and improved control proxies consistent with potential energy savings. The findings confirm that hybrid tomographic imaging combined with RL-based control provides a promising pathway toward sustainable, intelligent crystallization processes with enhanced product quality and energy efficiency.

Technological advancements in medical imaging techniques are opening new possibilities for diagnostics and monitoring health conditions. This study aimed to develop and evaluate a portable ultrasound-impedance tomograph designed for long-term monitoring of the lower urinary tract. This device combines ultrasound and impedance technologies, enhancing imaging accuracy and the non-invasiveness of procedures, which is particularly crucial for patients requiring regular examinations. The study used a prototype tomograph on patients with lower urinary tract disorders. To assess the device's effectiveness, images obtained from traditional diagnostic methods were compared with those generated by the new tomograph. This device utilizes advanced ultrasound beamforming technology and multiplexing of measurement channels, allowing for rapid and accurate diagnostics without requiring invasive sensor placement within the patient's body. The findings indicate that the newly developed tomography provides high-resolution and high-contrast images, facilitating better pathology identification than traditional methods. It was also demonstrated that the device effectively monitors changes over time, crucial for planning long-term treatment and monitoring patients. The development of this device opens new possibilities in diagnosing and monitoring medical conditions, enabling more precise and less burdensome diagnostic procedures. Its application could significantly improve the quality of life for patients and the efficacy of therapies in urology and other medical fields.