This research aims to evaluate the effectiveness of protective coatings in preventing the corrosion of steel in the marine environment. Electrochemical tests were performed on S355JR steel immersed in natural seawater (Black Sea, Port Constanta) over a period of 22 weeks, using electrochemical techniques such as the evolution of the open circuit potential (OCP) and linear polarization resistance to calculate R_p and the corrosion rate (V_corr). The investigated steel surfaces included (a) S355JR steel blasted with Al₂O₃, (b) S355JR steel blasted and coated with epoxy primer enriched with zinc, (c) S355JR steel blasted and coated with epoxy primer and polyurethane paint, and (d) S355JR steel blasted and subsequently coated with epoxy primer and then polyurethane paint to which kreutzonit particles had been added. The proportion of kreutzonit particles added to the polyurethane paint was 2 wt% of the total mass of the paint. Subsequently, the samples were subjected to morphological analyses and cross-sectional analysis by scanning electron microscopy (SEM), topographical characterization (roughness and microhardness), and structural assessments (FTIR and XRD), as well as an analysis of hydrophobicity (contact angle). The results of this study revealed significant differences in corrosion behavior between the different surfaces and coatings tested. Electrochemical analysis revealed that the coating with epoxy primer and polyurethane paint to which kreutzonit particles had been added provided the best corrosion protection in the marine environment during immersion.

Background/Objectives: Magnetic nanoparticles, particularly iron oxide-based materials, such as magnetite (Fe₃O₄), have gained significant attention as contrast agents in medical imaging This study aimsto syntheze and characterize Fe₃O₄-based core–shell nanostructures, including Fe₃O₄@TiO₂ and Fe₃O₄@SiO₂, and to evaluate their potential as tunable contrast agents for diagnostic imaging. Methods: Fe₃O₄, Fe₃O₄@TiO₂, and Fe₃O₄@SiO₂ nanoparticles were synthesized via co-precipitation at varying temperatures from iron salt precursors. Fourier transform infrared spectroscopy (FTIR) was used to confirm the presence of Fe–O bonds, while X-ray diffraction (XRD) was employed to determine the crystalline phases and estimate average crystallite sizes. Morphological analysis and particle size distribution were assessed by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and transmission electron microscopy (TEM). Magnetic properties were investigated using vibrating sample magnetometry (VSM). Results: FTIR spectra exhibited characteristic Fe–O vibrations at 543 cm⁻¹ and 555 cm⁻¹, indicating the formation of magnetite. XRD patterns confirmed a dominant cubic magnetite phase, with the presence of rutile TiO₂ and stishovite SiO₂ in the coated samples. The average crystallite sizes ranged from 24 to 95 nm. SEM and TEM analyses revealed particle sizes between 5 and 150 nm with well-defined core–shell morphologies. VSM measurements showed saturation magnetization (Ms) values ranging from 40 to 70 emu/g, depending on the synthesis temperature and shell composition. The highest Ms value was obtained for uncoated Fe₃O₄ synthesized at 94 °C. Conclusions: The synthesized Fe₃O₄-based core–shell nanomaterials exhibit desirable structural, morphological, and magnetic properties for use as contrast agents. Their tunable magnetic response and nanoscale dimensions make them promising candidates for advanced diagnostic imaging applications.

The aim of the present study was to evaluate the contamination state of the surface soil from 10 parks from Galati, Romania, and the health hazards of the soil. The soil samples, collected in each site from the playing ground and from the edge of the park, were analyzed by using combined Wavelength- (WDXRF) and Energy-Dispersive (EDXRF) X-ray fluorescence techniques. A total number of 27 chemical elements (Ag, Al, As, Ba, Ca, Cd, Cr, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sb, Sc, Sn, Sr, Ti, V, Zn and Zr) were quantified in the urban soils, and the results were compared to the normal and alert values from Romanian legislation for toxic trace elements, as well as with European and world average values of element concentrations. The mineralogical analyses were performed by Scanning Electron Microscopy with Energy-Dispersive X-ray Analysis (SEM-EDX) and the Attenuated Total Reflectance–Fourier Transform Infrared technique (ATR-FTIR). To assess the soil contamination and the impact on human health of the presence of potential toxic elements and heavy metals in the soil, a series of pollution and health risk indices were used. All the results indicated an unpolluted to moderately polluted soil. The soil samples collected from the edge of the parks presented higher values for the specific pollutants, which originated from heavy traffic, such as Cu, Cr, Zn and Pb. The non-carcinogenic and carcinogenic risk to children was assessed using estimated daily intake (EDI) in relation to the pathways whereby pollutants can enter the human body, such as ingestion, dermal contact, inhalation and vaporization. Using the obtained values for EDI, the hazard quotient and hazard index were determined, which strengthen the formerly issued presumption that soil pollution is moderate and, by itself, does not present any threat to children’s health.

The pipeline transport industry is constantly developing due to the high efficiency, long life, varied diameters of the pipelines, but a significant problem is the corrosion that occurs because of the corrosive attack of the various environments in which the pipelines are used. This study deals with the ex situ characterizations (optical microscopy, scanning electron microscopy coupled with energy dispersive X-ray analyses, X-ray diffraction analysis, roughness, and Vickers hardness analyses) and the in situ characterizations (gravimetric and electrochemical methods). Samples of steel were tested at immersion time, after 336 h, 672 h, 1344 h, 2016 h, and 4032 h of exposure to a 3.5% NaCl solution and drinking water. The corrosion rate evaluated with the gravimetric method varied between 0.036518 and 0.008993 mm/year in the 3.5% NaCl solution and 0.02834 and 0.034162 mm/year in drinking water. The electrochemical method resulted in an estimated corrosion rate range of 0.097–0.681 mm/year for the 3.5% NaCl solution, and 0.028–0.0472 mm/year for drinking water. The passivation effect, lifetime, and operating limit of the S235JR steel in the tested corrosive environments were studied. The study can provide technical support to increase the service life of S235JR steel and to predict the suitable environment reduce corrosion costs.

The scientifically backed conclusion that pollution with particulate matter presents an important negative effect on human health is the driver of the present study. Not only are the results presented herein a completion, and to some small extent a confirmation, of a previous study, but these findings are also a confirmation of the need to further investigate the best way for monitoring particulate matter pollution in agglomerated areas throughout the world. This need is emphasized by the moderately positive results obtained in this measuring campaign that was carried out in an indoor location of an industrial city and near a heavily circulated road. The results presented in this study were obtained by utilizing advanced methods such as optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD).

This study presents an integrated experimental and numerical investigation of the Refill Friction Stir Spot Welding (RFSSW) process applied to dissimilar aluminum alloys. The primary objective is to evaluate the mechanical and thermal behavior of the joints and to identify key process parameters influencing weld quality. Experimental welding trials were performed on aluminum alloy sheets using RFSSW, followed by shear testing and metallographic analysis to assess joint integrity, microstructure evolution, and fracture behavior. Infrared thermography and temperature sensors were employed to monitor heat distribution during welding. In parallel, a finite element model was developed to simulate the thermal cycle and stress distribution within the welded region. The numerical results showed good agreement with the experimental data, particularly regarding peak temperature and cooling trends at specific distances from the tool center. The findings demonstrate that RFSSW can successfully join dissimilar aluminum alloys with minimal defects when optimized parameters are applied. The combination of experimental observations and FEM simulation provides valuable insights into the underlying thermomechanical phenomena and offers a foundation for further process optimization.