We present a study of structure, microstructure, nanostructure and magnetic state of the CexPrNdSm (x = 0.01-1.5) medium-entropy alloys composed of the light rare earths only. Magnetic light rare earths are fundamentally different from the heavy ones, because the crystal-field interaction in the former is able to reduce or completely destroy the ionic magnetic moments at low temperatures. The alloys crystallize in a double hexagonal close-packed structure in the form of a single-phase nanostructured solid solution. The low-temperature magnetic state is inhomogeneous, being a mixture of paramagnetic domains appearing in the crystal regions with larger destruction of the moments and spin glass (SG)-type spin domains in the regions with less destructed moments. Such mixed state is intrinsic and specific to the light-lanthanide multi-component solid solutions. The SG-type domains are magnetically frustrated spin entities with broken ergodicity below the spin freezing temperature Tf. In the low-Ce content alloys, the SG-type domains resemble canonical SGs, while in the Ce-concentrated alloys, some ferrimagnetically ordered clusters with nonzero spontaneous magnetization have formed additionally. The increased Ce content x continuously reduces the average exchange coupling, as evidenced from the shift of Tf towards lower temperatures and the speed-up of spin dynamics into the direction of superparamagnets.

Pt (111)/Co (0001) multilayers are widely employed in spintronics due to the strong perpendicular magnetic anisotropy (PMA) generated at the interface, as well as their ability to stabilize magnetic skyrmions thanks to strong Dzyaloshinskii-Moriya interaction (DMI). In this study, we show that a hexagonal Co supercell grows epitaxially on a Pt supercell, consistent with a correspondence of 11 Co to 10 Pt atomic chains. This particular epitaxial relationship offers new insights into previous observations made by scanning tunneling microscopy. The Co films initially grow in the hexagonal close-packed (hcp) structure, followed by a face-centered cubic (fcc) structure at larger thicknesses, as shown by X-ray diffraction and transmission electron microscopy. After identifying the onset of Co–Pt intermixing above 600 K, the magnetic properties of Co films grown on Pt at 300 and 450 K were investigated. We were able to confirm the contribution of the interface to the magnetic properties by measuring the hysteresis loops using in situ magneto-optic Kerr effect, which enabled reliable measurements for both uncoated and coated Co films. PMA and Kerr rotation are enhanced for films grown at 450 K. Finally, we show that carbon contamination is not detrimental to PMA and can even contribute positively to the anisotropy.

In this study, the effect of adding calcium or strontium to Al-Mn and Al-Mn-Cu alloys on the formation of quasicrystals (QCs) is investigated. The alloys were cast in a massive copper mould with a cavity diameter of 3 mm. The cast alloys were characterised by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and electron backscatter diffraction. The addition of either calcium or strontium to Al-Mn and Al-Mn-Cu alloys promotes the formation of icosahedral QCs (IQCs). The results also show that neither calcium or strontium are integral part of the QC phases formed in these alloys. The results further indicate considerable differences in the composition of decagonal QC (DQC) phases in Al-Mn-Cu alloys without and with either calcium or strontium, whereas the electron-atom ratio according to Mizutani shows almost negligible differences. The effectiveness of calcium and strontium in promoting the formation of IQCs is attributed to a reduced surface tension of the Al-based melt. This consequently leads to a decrease in the critical radius for nucleation of IQCs.

Frictional behavior of molybdenum thin films deposited by Glancing Angle Deposition (GLAD) was investigated at various deposition angles (a) using single-scratch tests under different loads and directions. Films deposited at a >= 50 degrees developed elliptical columnar structures, resulting in orthotropic anisotropy due to direction-dependent plastic deformation. Increasing the deposition angle enhanced intercolumnar porosity, thereby reducing both friction and anisotropy. Conversely, the film deposited at a = 40 degrees exhibited strong anisotropy and a non-Coulombic frictional response. Moreover, this film showed non-centrosymmetric behavior, requiring a non-linear model to accurately describe its frictional anisotropy.

Thermomagnetic technologies provide an innovative pathway for recovering low-grade waste heat, leveraging the temperature dependence of magnetic properties for energy conversion. In this study, FeNiMnGaSi-based High Entropy Alloys (HEAs) are synthesized and characterized to evaluate their potential for thermomagnetic applications. The alloys were designed according to high-entropy criteria to obtain Rare-Earth-free compositions, mainly based on sustainable and high-availability elements, exhibiting second-order Curie-type transitions within the temperature range suitable for low-grade heat recovery. Structural analyses confirm a body-centered cubic structure with a high degree of compositional uniformity, while magnetic measurements demonstrate single-phase Curie transitions near room temperature, making these materials ideal candidates for thermomagnetic conversion. To complement the experimental measurements, calculations based on magnetization data are performed to estimate the magnetic work produced during ideal thermomagnetic cycles. The results confirm the suitability of both alloys for thermomagnetic applications, demonstrating significant energy conversion potential. In-operando tests in a bespoke thermomagnetic motor prototype confirm their ability to deliver high mechanical and electrical power outputs, 4 mW cm-3 and 2.8 mW cm-3 respectively, surpassing benchmark values reported in the literature. These findings establish the potential of HEAs for advancing thermomagnetic technologies and enabling efficient and sustainable energy applications.

Advanced surfaces combining biocompatibility with antibacterial properties are of prime interest in the biomedical field. In this context, ternary thin film metallic glasses of the Zr-Cu-Ag system with low silver contents (2 and 4 at. %) were deposited by magnetron sputtering and studied regarding their mechanical, microstructural, and antibacterial properties. The effect of further laser texturing of the PVD-deposited films, promoting Laser-Induced Periodic Surface Structures (LIPSSs), was also investigated. Results were then discussed in light of the chemical composition of films on the one hand and on the topographic characteristics of laser-treated surfaces on the other hand. Ternary films exhibited the expected metallic glass structure, with good associated mechanical properties. Besides, the low contents of Ag were sufficient to promote a significant antibacterial action against Escherichia coli, still enhanced by ultrafast laser texturing. Textured areas were also identified as prone to limit bacterial colonization due to the combined effect of the hydrophobic character of the treated surfaces together with a killing contact interaction.

Due to the high toxicity and carcinogenicity of Cr(VI), wastewater should be treated to remove Cr(VI) before discharge. In this study, water purification was achieved through the adsorption of Cr(VI) using an Fe-MOF/NiAl-LDH composite (FML), where the Fe-MOF was grown in situ on the NiAl-LDH. This composite used AlOOH, a by-product of the aluminum-water hydrogen production system, as one of its precursors, thereby achieving resource reuse. Since the material has a higher specific surface area and more active adsorption sites than NiAl-LDH and Fe-MOF, with abundant anions and water molecules interspersed between the layers, the hexavalent chromium can be effectively removed by electrostatic adsorption on the surface of the material, interlayer anion exchange, and reduction reaction. The effects of composite material type, contact time, solution pH, adsorbent dosage, initial Cr(VI) concentration, competitive ions, and reuse on the adsorption efficiency were investigated in this study. The results indicated that when the initial concentration of Cr(VI) was 20 mg L-1, the adsorbent dosage was 0.8 g L-1, and pH was set at 6, 15-FML achieved the best removal efficiency for Cr(VI), with a removal rate of 91.08 % in 60 min. The adsorption isotherm of this material closely followed the Langmuir adsorption model, with a maximum adsorption capacity of 42.73 mg g-1 for Cr(VI). The materials prepared in this study exhibited excellent regenerative capacity, with the Cr(VI)-loaded adsorbents effectively regenerated using a Na2CO3 solution. The regenerated materials could be reused multiple times without significant changes in adsorption capacity or structural integrity.

Metal−organic frameworks (MOFs) represent an attractive family of materials for diverse biomedical applications due to their porosity, chemical versatility, and stimuli‐responsive properties. Next to their drug delivery and bioimaging applications, MOFs have been recently considered as efficient luminescent thermal probes. However, the relatively low thermal sensitivity together with the biocompatibility of most MOF thermometers limits their practical applications. Here, a series of new MOFs based on Zn ions and a rectangular tetratopic ligand H 4 TBAPy (1,3,6,8‐tetrakis(p‐benzoic acid)pyrene) is reported, demonstrating a temperature‐dependent photoluminescence (PL) with up to 2.12% K −1 relative thermal sensitivities over the 7 – 300 K temperature range. Using a topological design approach, the structure of the obtained MOFs is tuned from two‐ to three‐dimensions via solvent exchange in order to build the optimal structure of the PL thermometer. Then, the resulting MOFs have been exfoliated to obtain MOF nanosheets (NSs) to be easily injected into living organisms. As a result, MOF NSs, intracardiac injected or introduced into the digestive system of the Casper fish, reveal a 100% survival rate together with an efficient in vivo PL thermometry of organs, thereby, paving the way to a rational design of highly sensitive and biocompatible MOF‐based thermometers.

Constructing van der Waals heterojunctions with excellent properties has attracted considerable attention in the field of photocatalytic water splitting. In this study, four patterns, coined A, B, C, and D of Janus Ga2SSe/Bi2O3 van der Waals (vdW) heterojunctions with different stacking modes, were investigated using first-principles calculations. Their stability, electronic structure, and optical properties were analyzed in detail. Among these, patterns A and C heterojunctions demonstrate stable behavior and operate as direct Z-scheme photocatalysts, exhibiting band gaps of 1.83 eV and 1.62 eV. In addition, the suitable band edge positions make them effective for photocatalytic water decomposition. The built-in electric field across the heterojunction interface effectively inhibits electron-hole recombination, thereby improving the photocatalytic efficiency. The optical absorption coefficients show that patterns A and C heterojunctions exhibit higher light absorption intensity than Ga2SSe and Bi2O3 monolayers, spanning from the ultraviolet to visible range. Their corrected solar-to-hydrogen (STH) efficiencies are 13.60% and 12.08%, respectively. The application of hydrostatic pressure and biaxial tensile strain demonstrate distinct effects on photocatalytic performance: hydrostatic pressure preferentially enhances the hydrogen evolution reaction (HER), while biaxial tensile strain primarily improves the oxygen evolution reaction (OER). Furthermore, the heterojunctions exhibited enhanced optical absorption across the UV-visible spectrum with increasing hydrostatic pressure. Notably, a 1% tensile strain results in an improvement in visible light absorption efficiency. These results demonstrate that Ga2SSe/Bi2O3 heterojunctions hold great promise as direct Z-scheme photocatalysts for overall water splitting.

The asymmetric Schiff base prepared in situ from ethylenediamine and pyridine-2-carboxaldehyde reacts with Fe(ClO4)3·6H2O to form the Fe(II) complex [FeL2](ClO4)2 with L = N,N-diethyl-N′-(pyridin-2-yl)methylene)ethane-1,2-diamine, where the Fe(III) starting material has been unexpectedly reduced to Fe(II). This complex was characterized by elemental analysis, infrared spectra, single crystal and powder X-ray diffraction measurements, variable temperature DC magnetic measurement and room temperature Mössbauer spectroscopy. The asymmetric ligand L coordinates in a tridentate fashion through its pyridyl, azomethine and amino nitrogen atoms, generating a distorted octahedral geometry around the central metal ion. Variable temperature magnetic studies and a Mössbauer measurement show that the iron is locked in the low spin Fe(II) states.

In this study, a novel calcium phosphate/polyacrylamide copolymer/α-type hemihydrate gypsum (CPO/PAM/α-HHG) composite material was prepared by polymerising a stable inorganic CPO precursor, end-capped with triethylamine (TEA), with an organic polyacrylamide (PAM) hydrogel to form a CPO/PAM precursor solution. Subsequently, this precursor solution was mixed with inorganic α-hemihydrate gypsum. The effects of CPO/PAM precursor addition and CPO addition on the slurry flowability, initial setting time, and mechanical properties of hardened specimens of the CPO/PAM/α-HHG composite were investigated. The structural characteristics of the composites were analysed by XRD, FE-SEM, and TGA. The results show that the initial setting time of the CPO/PAM/α-HHG composites was 26.7 min, which was 140.5% longer than that of the pure water α-HHG system and 3.9% longer than that of the PAM/α-HHG system; additionally, the oven-dried specimens had a flexural strength of 27.59 MPa and a compressive strength of 68.48 MPa, which were 77.2% and 102.0% higher than those of the pure water α-HHG system and 38.8% and 14.1% higher than those of the PAM/α-HHG system, respectively. The wet compressive strength of the CPO/PAM/α-HHG composites was improved by 11.8% compared to that of the PAM/α-HHG system. A structural analysis showed that CPO promoted the gelation process of PAM and allowed the hydration reaction process of α-HHG to be fully carried out by slowing down the gelation process of the organic network, which led to the full development of both organic and inorganic networks, ultimately forming an interspersed inorganic/organic dual-network structure, which enhanced the comprehensive mechanical properties of the composites. This study provides a new idea for the modification of α-type hemihydrate gypsum and a new method for the preparation of high-utilisation and high-performance gypsum-based composites.

The transition from three-dimensional (3D) to two-dimensional (2D) semiconducting and insulating materials for micro- and opto-electronics is driven by an energy efficiency and device miniaturization. Herein, the simplicity of growth and stacking of 2D metal-organic framework (MOF) with such planar devices opens up new perspectives in controlling their efficiency and operating parameters. Here, the study reports on 3D to 2D MOF' structural transformation to achieve ultrathin nanosheets with enhanced insulating properties. Based on neutral N-donor ligands, the study designs and solvothermally synthesizes 3D MOFs followed by their thermal and solvent treatment to implement the transformation. A set of single crystal and powder X-ray diffraction, electron microscopy, Raman spectroscopy, numerical modeling, and mechanical exfoliation confirm the nature of the transformation. Compared with initial 3D MOF, its nanosheets demonstrate sufficient changes in electronic properties, expressed as tuning their absorption, photoluminescence, and resistivity. The latter allows to demonstrate the prototype of ultrathin memristive element based on a 4 to 32 nm MOF nanosheet with enhanced functionality (150 to 1400 ON/OFF ratio, retention time exceeding 7300 s, and 100 cycles of switching), thereby, extending the list of scalable and insulating 2D MOFs for micro- and opto-electronics.

The objective of this study is to characterize the radiative exchanges occurring in a wood-burning stove by using a combined approach of measurements with a spectrometer and an infrared camera. This combination enabled a detailed observation of thermal radiation emissions from the flames, combustion gases and surfaces of the stove. Analysis of the results shows that these measurement methods allow the flame and the wall temperatures to be estimated. A final test also quantified the radiation from the wood during combustion, highlighting its key role in maintaining the combustion process. These results provide a better understanding of the radiative processes in a wood stove.

Various methods have been explored to enhance thermoelectric efficiency, including the use of magnetic interactions. This study examines the connections between magnetism and thermoelectricity by investigating the thermoelectric properties of PbSnTeSe high-entropy alloy doped with magnetic Cr and Fe impurities using first-principles calculations based on the density functional theory. For n-type materials, the results show that magnetic doping with Cr significantly enhances thermoelectric effects. Cr doping effectively improves the Seebeck coefficient, mainly because Cr atoms primarily contribute near the Fermi level and introduce isolated flat bands into the energy band structure, which increases the slope of the density of states. The enhanced Seebeck coefficient consequently boosts the power factor, leading to an increase in the figure of merit (ZT ) value. At 300 K, the optimal ZT value increases from 1.0 in pure PbSnTeSe to 1.6 in Cr-doped PbSnTeSe. However, the impact of magnetic doping with Fe on thermoelectric effects is less pronounced, as the difference in thermoelectric properties between magnetic and nonmagnetic Fe doping is minimal. Both types of doping contribute to the increase in the Seebeck coefficient, thereby enhancing the thermoelectric figure of merit.

The present study focuses on under-ventilated compartment fires, by analysing the results of an experimental and numerical study about fires issuing from heptane pools in a compartment with an open door. This compartment has an aspect ratio (height/width) of the order of 1.8 and a doorway with an aspect ratio to 4, which is very different from conventional compartments. This type of geometry is therefore expected yield new results. The key parameters in this case are the ventilation factor (based on the door height and area) and the pool fire diameter. To analyse the combustion regimes, the fire Heat Release Rate (HRR) is split into two parts, namely, the HRR released inside and outside the compartment. To quantify these quantities, two experimental methods have been combined. The first one is based on temperature measurements inside the compartment. The second one combines measurements from radiative heat fluxes outside the compartment and images taken with visible cameras that provide the flame shape in order to evaluate the corresponding heat released rate. The experimental data have been compared to dedicated numerical simulations carried out with the CFD code Fire Dynamics Simulator. These comparisons have revealed that in a well-ventilated moderately under-ventilated regime, integral quantities such as mean temperature, fire heat release rate inside and outside the room appear to be well predicted by the simulations. However, under the same conditions, the temperature profiles show differences that can be locally significant. This observation might be explained by a difficulty in correctly reproducing the flame dynamics and the air flow entering through the door. Furthermore, in the severely under-ventilated case, the temporal evolution of the average quantities (HRR and mean temperatures) are very poorly estimated by the simulations, as well as the local distributions. this case the simulations predict that the combustion of all the combustible vapours occurs outside the door, which does not correspond to the physical observations. This phenomenon have been observed at Q* approximate to 1.6, where Q* is the dimensionless heat released rate. Therefore, improvements of the CFD code are required improve the simulations, probably also involving dedicated efforts on the ignition and extinction sub-models.

Addressing global energy and environmental issues calls for the development of effective photocatalysts capable of enabling solar-driven water splitting, a key route toward sustainable hydrogen generation. In this work, we conducted a detailed density functional theory (DFT) study on three bilayer van der Waals (vdW) heterojunctions, Ga2SSe/GaP, Ga2SSe/PtSSe, and Ga2SSe/SnSSe, each explored in four distinct stacking configurations, with Ga2SSe serving as the base monolayer. We assessed their structural stability, electronic properties, and optical responses to determine their suitability for photocatalytic water splitting. The analysis showed that Ga2SSe/GaP and Ga2SSe/SnSSe exhibit type-II band alignment, while Ga2SSe/PtSSe displays a type-I alignment. Electrostatic potential profiles and Bader charge calculations identified SeGa2S/SSnSe and SeGa2S/SeSnS as direct Z-scheme systems, offering efficient charge carrier separation and robust redox potential. For effective water splitting, the band edges must straddle the water redox potentials. Our results indicate that configurations A and B in Ga2SSe/GaP, along with C and D in Ga2SSe/SnSSe, fulfill this requirement. These four configurations also exhibit strong absorption in both the visible and ultraviolet spectral ranges. Notably, configurations C and D of Ga2SSe/SnSSe achieve high solar-to-hydrogen (STH) efficiencies, reaching 38.44% and 21.75%, respectively. Overall, our findings suggest that these direct Z-scheme heterostructures are promising candidates for water splitting photocatalysis.

Compartment fires present significant challenges in fire safety engineering due to their complex dynamics within enclosed spaces. The present study employs a two-zone model in order to analyze the combustion process, focusing on inflow air mass flow rate and outflow smoke mass flow rate. By deriving dimensionless expressions for these parameters, it establishes new simplified relationships between incoming mass flow rate, heat release rate, and compartment geometry. These findings might provide valuable insights for improving fire safety measures, optimizing architectural design, and enhancing emergency response strategies.

This study focuses on well-ventilated and under-ventilated fires and the comprehension of interrelated phenomena. To address the challenges in accurately modeling under-ventilated fires, this research evaluates the performance of the Fire Dynamics Simulator (FDS) through numerical simulations and experimental comparisons. To conduct our comparisons, two representative cases (well-ventilated and under-ventilated) were selected for analysis. Results reveal significant differences between well-ventilated and under-ventilated scenarios. Through detailed analysis, this work sheds light on FDS’s efficacy in capturing key fire dynamics parameters, such as gas temperature gradients and flow rate. The findings contribute to advancing our comprehension of fire behavior under different ventilation conditions.

Harnessing solar energy for photocatalytic water splitting and hydrogen fuel production necessitates the development of advanced photocatalysts with broad solar spectrum absorption and efficient electron-hole separation. In this study, we systematically explore the potential of the SGa2Se/TeMoS heterojunction as a water-splitting photocatalyst using first-principles calculations. Our results indicate that while the heterojunction exhibits type-II band alignment, its band edge positions are inadequate for initiating water redox reactions. To overcome this limitation, we successfully engineered a Z-scheme SGa2Se/Zr/TeMoS heterojunction by incorporating a Zr layer to modulate the charge transfer mechanism between the SGa2Se and TeMoS layers. The potential positions of the HER and OER in this Z-scheme heterojunction overcome the limitation of the bandgap on water decomposition, allowing the optimized heterojunction to exhibit suitable band edge positions for water splitting across a wide pH range (0 ≤ pH ≤ 11.3), from acidic to weakly basic conditions. Additionally, the heterojunction exhibits exceptional light absorption capabilities across the entire spectrum, particularly in the infrared and visible regions, which greatly enhances the utilization of solar energy and highlights its potential as an efficient broad-spectrum photocatalyst for water splitting.