Our study is focused on the structural and morphological characteristics, optical behaviour and photocatalytic properties of undoped and 5 at% Eu³⁺-, Gd³⁺- and Y³⁺-doped CeO₂ nanoparticles prepared by a green hybrid sol-gel combustion method. Several techniques such as X-ray diffraction powder (XRD), Transmission Electron Microscopy (TEM), UV-Vis spectroscopy, Photoluminescence spectroscopy (PL) and Electron Paramagnetic Resonance (EPR) have been used to investigate the obtained samples. Moreover, the correlation between the characteristics and properties has been studied. The nanoparticles observed by TEM exhibit a pseudo-spherical shape, except for Y³⁺-doped CeO₂, which presents an acicular shape. The average size of undoped and rare-earth-doped CeO₂ nanoparticles is below 10 nm, in good agreement with the calculations performed based on XRD analyses. From UV-Vis analyses it has been deduced that with doping the band gap energy decreases, which shows that additional levels are introduced by doping into the CeO₂ band gap. The EPR spectra evidence similar behaviour for all doped samples. The photocatalytic activity was evaluated by the degradation of rhodamine B (RhB) under UV light irradiation. The photodegradation mechanism has been studied in depth based on the formation of electron-hole pairs, and to evidence the reactive oxygen species, ESR coupled with spin-trapping experiments was performed. In the case of Y-doped CeO₂ nanoparticles, the generation of both •OOH and •${\mathrm{O}}_2^{-}$ radicals involved in RhB photodegradation was highlighted.

We present a comparative study of vortex pinning in chemically deposited YBa ₂ Cu ₃ O _7-x /BaZrO ₃ nanocomposite films, with the aim of correlating the preparation method to the superconducting properties. Two sets of samples have been prepared by different low fluorine routes (one set followed the in situ approach), with different starting YBCO coating solution and with a different amount of BaZrO ₃ . The short-range vortex pinning properties have been assessed using a contactless microwave (48 GHz) technique, which yielded the vortex pinning constant (Labusch parameter) k _p and the vortex viscosity θ as a function of the applied field up to 0.8 T, and for temperatures between 60 K and T _c . The results were compared to more usual (long-range vortex motion) J _c measurements. Despite the supposed similarity in pinning as determined from J _c , we found significant differences between the pinning properties of the two sets of samples. It appears that the in situ approach results in stronger pinning at microwaves in the whole temperature range explored, and that this behavior is due to the smaller dimensions of BaZrO ₃ nanoparticles. This information can be very useful in the search of optimized chemical route to strong pinning superconducting nanocomposite materials.

Polymer assisted deposition (PAD) was used as an environmentally friendly, non-fluorine, growth method for superconducting YBa₂Cu₃O_7−x (YBCO) films. The kinetics of the thermal decomposition of the precursor powder was studied by thermogravimetry coupled with mass spectrometry (TG-QMS). YBCO films were spin coated on (100) SrTiO₃ (STO) single crystalline substrates, followed by a single step thermal treatment under wet and dry O₂ and O₂/N₂ mixture. The as-obtained films were epitaxially grown having a [001]YBCO||[001]STO out-of-plane epitaxial relationship and exhibited good superconducting properties with T_c (R = 0) > 88 K, transition widths, ΔT ≈ 2 K and critical current densities as high as 2.3 MA/cm² at 77 K and self magnetic field.

We report the preparation and characterization of epitaxial LaNiO₃ (LNO) thin films by chemical solution deposition method using lanthanum and nickel acetylacetonates as starting reagents dissolved in propionic acid. In order to obtain further information regarding the decomposition behavior of the film, the precursor solution was dried to obtain the precursor powder, which was investigated by thermal analyses and X-ray diffraction measurements (XRD). The LNO perovskite thin films were deposited by spin coating on SrTiO₃(100) single crystal substrates. A detailed study with different crystallization temperatures (600–900 °C) at two different heating ramps (5 and 10 °C/min) was performed. Oriented LaNiO₃ thin films with good out-of-plane textures were obtained with optimal surface morphologies.

The role of diethanolamine (DEA) as a chelating agent was investigated in a fluorine-free precursor solution for the growth of superconducting YBa₂Cu₃O₇ (YBCO) thin films via chemical solution deposition. Infrared spectroscopy and thermal analyses were employed to elucidate the interactions between the chelating agent and propionate-based coating solution. The physical properties of the as-obtained YBCO films were investigated to assess the effect of DEA addition on film growth. Special emphasis was placed on the determination of superconducting transport properties. These have been investigated in wide magnetic field (0–18 T) and temperature (4.5–77 K) ranges to account for various possible application scenarios. The 100 nm thick YBCO film deposited on a (001) SrTiO₃ single-crystal substrate exhibited a critical current density of 4 MA cm⁻² at 77 K in self-field.

This study provides a comprehensive assessment of water infrastructure, consumption management, and educational practices across all public pre-university educational institutions in Cluj County, Romania. The research addresses the increasingly urgent imperative of sustainable water resource management within educational settings, in alignment with both European and global priorities. This analysis is based on a comprehensive data set collected in June 2025 from all 392 public pre-university educational institutions in Cluj County, encompassing both urban and rural areas, all educational levels, and all types of institutions. Data was gathered using a standardized questionnaire, which was validated with the official support of the Cluj County School Inspectorate. The quantitative analysis highlights significant urban–rural disparities: 95.566% of urban institutions are equipped with modern meters and connected to public water networks, compared to only 68.254% in rural areas. Water consumption monitoring relies predominantly on invoice data (69.388%), while the adoption of advanced monitoring technologies remains limited. Reported water losses are minimal (1.531%), and only 0.765% of educational institutions have indicated non-compliance issues related to water quality in the past three years. Educational measures and water-saving awareness campaigns are present in 65.562% of institutions, yet only about one-third (32.908%) have implemented dedicated projects or partnerships. The financial analysis reveals that 90.487% of annual water and sewerage costs are borne by urban institutions. The study highlights both the progress achieved and the persistent challenges, particularly in rural infrastructure and the expansion of educational interventions. The results provide a robust empirical basis for informing regional and national policies, supporting targeted investments, integrated educational programs, and continuous monitoring to ensure sustainable water resource management in the Romanian educational system.