Materials

The dynamic development of laser therapy in dentistry is associated, among other factors, with the bactericidal effect of the energy emitted by laser devices. Therefore, they are also helpful for decontamination. They are increasingly used in the treatment of peri-implantitis, a bacterial inflammation of peri-implant tissues that is the most severe late complication of implantation and a potential cause of implant loss. Therefore, this study aimed to assess the safety of laser decontamination of the implant surface with respect to its effect on the integrity of the implant structure. In the present study, blocks of the titanium alloys Ti-6Al4V and Ti6Al7Nb were fabricated using electron-beam powder bed fusion and laser powder bed fusion, respectively. These alloys, commonly used in implantology, here in the form of Ti block scaffolds, have been exposed to an Er³⁺:YAG laser under various parameters (energy range of 50–320 mJ, exposure times of 20 or 30 s), and their effects have been further observed. To determine the changes induced by the laser, the following techniques were used: X-ray diffraction (XRD), Rietveld refinement method, scanning electron microscopy (SEM) with EDS (Energy-dispersive X-ray Spectroscopy), and thermography. The results show that the proposed Ti6Al4V and Ti6Al7Nb scaffolds can be exposed to an Er³⁺:YAG laser without damage when the power is limited to 0.5 W.

Despite cement remaining a dominant material in the construction industry, researchers are increasingly exploring strategies to reduce its consumption by incorporating supplementary cementitious materials or by developing alternative binder systems utilising various ashes produced by power plants during the combustion of different waste streams. In this context, the present study investigates the influence of two types of oil shale ash on the pore structure of C–S–H under aggressive environmental conditions. To address these issues, a comprehensive pore structure analysis was conducted using nitrogen gas physisorption, applying multiple analytical approaches including Dubinin–Radushkevich, Horvath–Kawazoe, quench solid density function theory, and Barett–Joyner–Halenda for pore volume and pore size distribution. Pore surface fractal dimension obtained by Neimark Kiselev and Frenkel–Halsey–Hill was compared. The results revealed that the deterioration of C–S–H structure depends on the ash type and the exposure duration to the sulfate–chloride solution.

To evaluate the cracking characteristics of asphalt pavements under thermal stresses, the finite element (FE) software ABAQUS 2021 was used in this paper to establish thermal and mechanical parameter models, respectively. The temperature field distributions in winter and summer were analyzed according to the actual situation based on fracture mechanics theory and the extended FE method, as well as the most unfavorable crack type for crack propagation was also studied. Further, the impact of the propagation of transverse cracks on the road surface was investigated by changing the solar radiation, sunshine duration, and wind speed. Finally, the propagation pattern of reflective cracks was observed under the cyclic temperature field. The results show that under the action of the temperature field alone, type I cracks, which are cracks that undergo opening displacement due to the vertical tensile stress acting on the crack surface, are the main type of cracks, while the trend of crack propagation was much higher in winter than in summer. It was also found that changing the parameters of solar radiation, sunshine duration, and wind speed could significantly impact cracking. Under the cyclic temperature field, the length of reflective cracks was proportional to time, and the initial crack length significantly affected the pavement life. Therefore, pavement inspection should be more stringent in winter, and initial cracks should be avoided as much as possible during paving.