Search Results (505)

The stability, elasticity, and thermoelectric property of ABX₃ (A = K, Ag, Cu; B = Si_xGe_ySn_zPb_{(1−x−y−z)}; X = Br, I) metal halide perovskites (MHPs) with B-type medium entropy sub-lattices (MESLs) are investigated by first principles calculations. The results show that the order of dissociation formation enthalpy ${\Delta H}_{\mathrm{f}}$ for conventional unit cell APbX₃ with changing atomic type in the A site is K < Ag < Cu, and for each case Br < I. The ${\Delta H}_{\mathrm{f}}$ values of (KBBr₃, KBI₃, AgBBr₃) and (CuBBr₃, CuBI₃, AgBI₃) with MESL in the B site slightly increase and decrease, respectively, with the exception of certain situations. By using Slack’s model, the lattice thermal conductivity (LTC) ${\kappa }_l$ at finite temperatures is obtained. It is found that the LTC ${\kappa }_l$ for all MHPs shows an extremely low value at room temperature, not exceeding 1.5 Wm⁻¹K⁻¹. Interestingly, it is also found that the B-type MESLs significantly increase the ZT_max values of KPbX₃, whereas they decrease the ZT_max values of CuPbX₃ and AgPbX₃, except for in some cases. All calculated parameters show obvious variation laws with the increase in atomic number of the high-content B-type atom in the ABX₃, and CuBX₃ and AgBX₃ materials exhibit an extremely low ZT value (ZT ≈ 0) due to their high σ accompanied by high ${\kappa }_e$ and low S. We believe that KSi_0.375Ge_0.25Sn_0.25Pb_0.125Br₃ with a ZT value of 3.012 can serve as an excellent thermoelectric material at room temperature. These findings make contributions to the design of high-quality thermoelectric MHP materials. Full article

Drought stress severely constrains plant growth and productivity. To mitigate water loss, plants primarily regulate stomatal aperture through the Abscisic acid (ABA) signaling pathway, where the Sucrose Nonfermenting 1-Related Protein Kinase 2 (SnRK2) family kinase Open Stomata 1 (OST1) acts as a central positive regulator. However, the upstream regulators that fine-tune OST1 activity remain incompletely characterized. Aliphatic Suberin Feruloyl Transferase (ASFT), a BAHD acyltransferase essential for suberin aromatic monomer biosynthesis, was previously uncharacterized regarding its function in leaves. Here, we report that ASFT negatively regulates drought tolerance in Arabidopsis thaliana by directly interacting with OST1 and inhibiting its autophosphorylation, thereby restricting stomatal aperture. Consistent with this, the asft mutant exhibited decreased water loss and enhanced survival under drought, whereas ASFT-overexpressing lines showed opposite phenotypes. BiFC, Co-IP and in vitro kinase assays confirmed that ASFT directly interacts with OST1 and suppresses its autophosphorylation, while dehydration-induced OST1 phosphorylation was elevated in the asft mutant. Genetic evidence confirmed that ASFT functions upstream of OST1. This study reveals a moonlighting role for this suberin biosynthetic enzyme in ABA signaling and provides a potential target for breeding drought-resistant crops. Full article

A high-entropy strategy has emerged as a promising approach to enhance the functional properties of piezoelectric ceramics for biomedical applications. For this reason, we have designed two novel high-entropy ceramics, (Bi_1/2Na_1/2)(Zr_1/3Sn_1/3Ti_1/3)O₃(BNZST) and (Bi_1/2Na_1/2)(Zr_1/4Sn_1/4Hf_1/4Ti_1/4)O₃(BNZSHT), which were synthesized via a two-step solid-state reaction. The phase structure, surface morphology, biocompatibility, and in vitro bioactivity were assessed. The results showed both ceramics adopted perovskite structures. BNZST and BNZSHT ceramics had relatively even crystallite sizes and element distribution, as well as achieving piezoelectric (d₃₃ ≥ 78 pC/N) properties. In vitro tests confirmed a high relative cell growth rate (RSG, >80%) after co-culturing BNZST or BNZSHT ceramic with murine fibroblasts L929 for more than 3 days. In particular, the surface with electric charge enhanced L929 with more extensive, widespread, and dense proliferation for the BNZST ceramic compared to ceramics without BNZST or unpolarized BNZST. The above indicated that multi-element doping and entropy stabilization established a novel pathway for developing a high-entropy bio-piezoelectric ceramics with high biocompatibility and bioactivity, providing the possibility for their use in bone repair materials. Full article

This study investigates the presence of Technology-Critical Elements in the Trepça mine (Stan Tërg, Mitrovicë), representing the first assessment of their distribution within this mining district. Samples were collected in all ore bodies (three samples per ore body) in horizons VIII-XI. Mineralogical, geochemical and microstructural characterization was performed using X-ray diffraction (XRD), Inductively Coupled Plasma Mass-Spectrometry (ICP-MS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The analyses confirmed the presence of several Technology-Critical Elements, especially Bi, Co, Ge, W, Ga, In, Te and Sb, whose distribution, correlation with mineral phases and structure were also identified. XRD enabled the identification of mineral phases while SEM-EDX provided structural and morphological characteristics of these mineral phases. The ICP-MS results indicate significant variability in the distribution of these elements. Bi reached extremely high concentrations (up to 2570.68 ppm in ore body 136), well above the method detection limit (MDL = 0.01 ppm), whereas Co exhibited elevated yet moderate concentrations that increased with depth, indicating a depth-dependent rise in concentration. V, W, Sb and Sn also exhibited elevated concentrations. Peak enrichment levels were observed for Bi (up to 2750 ppm) in Horizon IX, Sb (up to 504 ppm) in Horizon XI, W (up to 308 ppm) in Horizon VIII, and In (up to 34,730 ppm) within selected ore bodies, indicating pronounced vertical geochemical zonation. The results demonstrate that selected ore bodies represent significant potential sources of Technology-Critical Elements, supporting future resources and strategic raw material assessment within the Trepça mining district. Full article

A ceramic anode made of Sb-doped SnO₂ and coated with a photoactive BiPO₄ layer was tested for the (photo)electrochemical oxidation of three commonly used pharmaceuticals: atenolol, ibuprofen, and norfloxacin. Light-pulsed chronoamperometry showed that the photoanode responded immediately to illumination. The application of light and current enhanced degradation for all compounds when treated separately. Ibuprofen and norfloxacin exhibited higher degradation than mineralization, which demonstrates their persistent nature. Electric current was essential to achieve efficient degradation and mineralization, demonstrating the effectiveness of the electrochemical approach. For multicomponent mixtures, applying light resulted in higher mineralization compared to dark conditions at low operation currents (0.2 A). At higher currents (0.4–0.8 A), the contribution of light was partially masked by the enhanced electrochemical production of hydroxyl radicals. The analysis of individual compounds within the mixture revealed significant improvements in degradation under light exposure. Overall, these results demonstrate the potential of the Sb-doped SnO₂ ceramic photoanode as a cost-effective and promising alternative to commercial materials for treating pharmaceutical contaminants. Full article

This study applies a hotspot-based spatial statistical approach to investigate the spatial distribution of chemical elements and to improve regional geochemical baseline estimation in topsoils affected by widespread anthropogenic influence. Specifically, this study applied the Getis–Ord Gi* Hotspot analysis on over 7000 topsoil samples from the Campania region (southern Italy), focusing on 21 variables. The analysis revealed statistically significant clusters of high and low concentrations, closely aligned with regional geological features. Elevated levels of As, Ba, Be, Bi, Cu, Sr, Th, Tl, U, and V were mainly observed in soils developed on volcanoclastic deposits, whereas Co, Cr, Ni, and Mn were more common in soils on siliciclastic units. Cd, Hg, Pb, Sb, Sn, and Zn exhibited clustered anomalies in major urban and industrial areas, indicating anthropogenic sources. For these elements, baseline values were estimated. Traditional statistical methods, which primarily rely on data distribution, often overlook spatial autocorrelation, leading to biased thresholds, particularly in areas with widespread contamination. The hotspot-based approach addresses this limitation by excluding hotspot clusters from the calculation of the 95% Upper Tolerance Limit (UTL95-95), thereby providing baseline thresholds uninfluenced by human activity. Comparison with other data-driven methods showed consistent trends across lithologies, although the hotspot-based approach tended to yield slightly lower thresholds, reflecting its responsiveness to spatial patterns. Full article

This study investigates the genesis of gold mineralization at the Rodruin prospect in the central Eastern Desert (CED) of Egypt, with the aim of constraining the relative contributions of metamorphic and magmatic fluids to ore formation. Gold mineralization at Rodruin is hosted by quartz–carbonate veins emplaced within a shear zone that transects low-grade metasedimentary sequences intruded by Ediacaran post-tectonic granitoids. It exhibits characteristics transitional between orogenic turbidite-hosted and polymetallic vein-type mineralization. Although metamorphic devolatilization is interpreted to have generated the dominant ore-forming fluids, adjacent granitoid intrusions acted primarily as a thermal engine, with only a limited direct input of magmatic-hydrothermal fluids. This interpretation is supported by the occurrence of magmatic-affiliated mineral inclusions (monazite, cassiterite, and zircon) coupled with generally low concentrations of trace elements typically enriched in granitic magmatic-hydrothermal fluids (Sb, Bi, Mo, W, Sn, Nb, and Ta), collectively indicating a subordinate magmatic contribution. Rare earth element (REE) patterns of the ore samples closely resemble those of the nearby granitoids, displaying LREE enrichment; however, a distinct positive Eu anomaly is restricted to the ore assemblages and is attributed to hydrothermal feldspar alteration supporting magmatic involvement in ore formation. Carbon and oxygen isotope compositions (δ¹³C = −6.6 to −2.36‰; δ¹⁸O = +15.7 to +19.7‰), together with REE signatures comparable to primitive mantle values and textural evidence for synchronous sulfide–carbonate precipitation, manifested by rhythmic banding of carbonates and sulfides unequivocally indicate a hydrothermal–metasomatic origin. Collectively, these lines of evidence support a hybrid metamorphic–magmatic model in which gold and associated base metals were predominantly transported by metamorphic fluids, whose mobilization and focusing were enhanced by the thermal influence of Younger granitic intrusions, whereas magmatic-hydrothermal fluids contributed only a minor proportion to the overall metal budget. Full article

With the ongoing miniaturization of solder joints in three-dimensional integrated electronic packaging, electromigration reliability has become a pressing concern. This study systematically examines the interfacial intermetallic compound (IMC) growth behavior of Cu/Sn-58Bi/Cu joint under electromigration (EM) with a symmetrical square-wave alternating current (AC). Electron backscatter diffraction (EBSD) was employed to perform statistical spatial analysis of Sn grain orientations within the joints to reveal the growth mechanism of interfacial IMC. Results demonstrate that the AC field markedly enhances the anisotropy of IMC growth in Cu/Sn-58Bi/Cu joints, exhibiting two phenomena: uniform growth on both sides and rapid growth (polar growth) on one side of the interfacial IMC. Among them, the IMC thickness difference characterization quantity Δ_IMC reached as high as 45.56% for the latter. This is attributed to the directional regulation of atomic migration rate by Sn grain orientation (the angle θ between the c-axis and the electron flow) and is further amplified by the altered atomic diffusion pathways imposed by the Bi phase distribution. Specifically, the Sn grains exhibit a pronounced preferential orientation mode along the current path (horizontal direction), with an orientation gradient of 0.915 μm⁻¹. The arrangement of Bi-rich phases alters the distribution of Sn grains in Cu/Sn-58Bi/Cu joints, thereby reshaping the internal electron transport pathways and significantly intensifying the orientation-dependent effect of IMC growth. Moreover, Sn grains adjacent to the Bi-rich phase boundaries (phase boundary grains) display a stronger tendency for c-axis orientation parallel to the current direction, exhibiting an average effective orientation parameter 1.948 times greater than that of bulk grains, which establishes a well-defined spatial orientation gradient. Full article

Bi-doped low-silver Sn-Ag-Cu solders are increasingly gaining attention in advanced electronic packaging due to their cost-effectiveness and enhanced mechanical properties. However, the thermo-mechanical reliability mechanisms of such modified solders, particularly Sn-0.3Ag-0.7Cu-3Bi (SAC0307-3Bi) within Ball Grid Array (BGA) assemblies, remain insufficiently understood. To address this gap, this research proposes a comprehensive assessment framework integrating constitutive parameter calibration with finite element analysis (FEA) to accurately characterize the mechanical behavior and fatigue durability of SAC0307-3Bi solder joints under cyclic thermal loads. The Anand viscoplastic parameters were first calibrated via the Norton creep law and virtual tensile tests. Subsequently, a 3D quarter-symmetry model was constructed to replicate thermal cycling conditions between 25 °C and 125 °C. Simulation data reveal a strong correlation between stress concentration and the Distance to Neutral Point (DNP), pinpointing the chip-side interface of the corner joint as the critical failure site. Moreover, creep strain was observed to accrue in a “step-wise” pattern, predominantly during the heating and cooling ramps, reflecting distinct temperature sensitivity. Utilizing the Syed model, the fatigue life was estimated at approximately 2239 cycles. These insights serve as a crucial benchmark for designing robust packages using Bi-doped, low-silver lead-free solders. Full article

At the Ity gold deposit (Ivory Coast), carbonate-buffered tropical weathering fundamentally controlled the redistribution and enrichment of gold and associated metals within the Flotouo weathering profile. Primary mineralisation formed through skarn development at quartz diorite contacts, followed by mesothermal stages around 2 Ga, establishing the initial Au and trace-metal endowment. Hypogene processes alone, however, cannot explain the present distribution and concentration of Au, Cu, Mo, Bi, Sn, and W. Cenozoïc tropical weathering profoundly transformed the ores through coupled sulphide oxidation and carbonate dissolution. Oxidation of sulfides releases metals into circulating fluids. At the same time, dissolution of marble lenses buffered the pH towards near-neutral conditions, limiting long-distance metal transport and favouring local residual enrichment and secondary immobilisation. These processes, together with leaching of Ca, S, and Si, increased porosity and permeability, promoted fluid flow through karstic voids and collapse breccias. A lateritic blanket extends above the saprolitised hypogene ores. A systematic vertical mineralogical zonation developed across the profile, with goethite-dominated laterite at the top, kaolinite-rich saprolite in the middle, and smectite-bearing horizons at depth. This study highlights the key role of pH-buffered tropical lateritisation in upgrading pre-existing skarn-related mineralisation and producing atypical trace-metal enrichments in Birimian gold systems, providing a mechanistic framework relevant for regional exploration models. Full article

The six platinum group elements (PGE) are among the rarest elements in the upper continental crust of the earth. Higher values of PGE have been detected in the upper mantle and in chondrite meteorites. The PGE are siderophile and chalcophile elements and are divided into the following: (1) the Ir subgroup (IPGE) = Os, Ir, and Ru and (2) the Pd subgroup (PPGE) = Rh, Pt, and Pd. The IPGE are more refractory and less chalcophile than the PPGE. High concentrations of PGE led, in rare cases, to the formation of mineral deposits. The PGE are carried in discrete phases, the platinum group minerals (PGM), and are included as trace elements into the structure of base metal sulphides (BM), such as pentlandite, chalcopyrite, pyrite, and pyrrhotite. Similarly to PGE, the PGM are also divided into two main groups, i.e., IPGM composed of Os, Ir, and Ru and PPGM containing Rh, Pt, and Pd. The PGM occur both in mafic and ultramafic rocks and are mainly hosted in stratiform reefs, sulphide-rich lenses, and placer deposits. Presently, there are only 169 valid PGM that represent about 2.7% of all 6176 minerals discovered so far. However, 496 PGM are listed among the valid species that have not yet been officially accepted, while a further 641 are considered as invalid or discredited species. The main reason for the incomplete characterization of PGM resides in their mode of occurrence, i.e., as grains in composite aggregates of a few microns in size, which makes it difficult to determine their crystallography. Among the PGM officially accepted by the IMA, only 13 (8%) were discovered before 1958, the year when the IMA was established. The highest number of PGM was discovered between 1970 and 1979, and 99 PGM have been accepted from 1980 until now. Of the 169 PGM accepted by the IMA, 44% are named in honour of a person, typically a scientist or geologist, and 31% are named after their discovery localities. The nomenclature of 25% of the PGM is based on their chemical composition and/or their physical properties. PGM have been discovered in 25 countries throughout the world, with 64 from Russia, 17 from Canada and South Africa (each), 15 from China, 12 from the USA, 8 from Brazil, 6 from Japan, 5 from Congo, 3 from Finland and Germany (each), 2 from the Dominican Republic, Greenland, Malaysia, and Papua New Guinea each, and only 1 from Argentine, Australia, Bulgaria, Colombia, Czech Republic, England, Ethiopia, Guyana, Mexico, Serbia, and Tanzania each. Most PGM phases contain Pd (82 phases, 48% of all accepted PGM), followed, in decreasing order of abundances, by those of Pt 35 phases (21%), Rh 23 phases (14%), Ir 18 phases (11%), Ru 7 phases (4%), and Os 4 phases (2%). The six PGE forming the PGM are bonded to other elements such as Fe, Ni, Cu, S, As, Te, Bi, Sb, Se, Sn, Hg, Ag, Zn, Si, Pb, Ge, In, Mo, and O. Thirty-two percent of the 169 valid PGM crystallize in the cubic system, 17% are orthorhombic, 16% hexagonal, 14% tetragonal, 11% trigonal, 3% monoclinic, and only 1% triclinic. Some PGM are members of a solid-solution series, which may be complete or contain a miscibility gap, providing information concerning the chemical and physical environment in which the mineral was formed. The refractory IPGM precipitate principally in primitive, high-temperature, mantle-hosted rocks such as podiform and layered chromitites. Being more chalcophile, PPGE are preferentially collected and concentrated in an immiscible sulphide liquid, and, under appropriate conditions, the PPGM can precipitate in a thermal range of about 900–300 °C in the presence of fluids and a progressive increase of oxygen fugacity (fO₂). Thus, a great number of Pt and Pd minerals have been described in Ni-Cu sulphide deposits. Two main genetic models have been proposed for the formation of PGM nuggets: (1) Detrital PGM represent magmatic grains that were mechanically liberated from their primary source by weathering and erosion with or without minor alteration processes, and (2) PGM reprecipitated in the supergene environment through a complex process that comprises solubility, the leaching of PGE from the primary PGM, and variation in Eh-pH and microbial activity. These two models do not exclude each other, and alluvial deposits may contain contributions from both processes. Full article

Efficient conversion of biomass-based platform molecules into high-value derivatives is recognized as one formidable challenge in biomass upgrading. In this work, a one-pot deep eutectic solvents-assisted solvothermal method was developed for the modification of the commercial Pt/C catalysts by introducing a secondary metal (M = Sn, Bi, Ge, Sb, Pb). The structural and electronic properties of the catalysts were precisely tuned. Among the screened metals, the addition of Sn yielded the most significant improvement in catalytic activity. The optimized PtSn_0.5/C-140 catalyst achieved superior furfural (FAL) conversion and furfuryl alcohol (FOL) selectivity under mild conditions (20 °C, 2 MPa H₂). Comprehensive characterizations, including XRD, HRTEM, XPS, and H₂-TPD, confirmed the formation of Pt-Sn solid-solution phase. Furthermore, Characterization and reaction results revealed that the electronic and geometric effects induced by Sn modulated Pt active sites, significantly enhancing the adsorption of the active H species. Additionally, the SnO_x species adjacent to the Pt-Sn sites served as hydrogen spillover acceptors, further accelerating the hydrogenation process. The synergy between the Pt-Sn solid-solution phase and SnO_x species is identified as the origin of the superior performance at room temperature. These findings provide a new strategy for the design of high-performance biomass conversion catalysts by upgrading commercial noble metal catalysts. Full article

This study presents a comprehensive investigation of the micro-wetting behavior of SAC305 and SnBi58 solders on chip components. Micro-wetting balance tests, which employ small solder globules, enable direct evaluation of solder wettability on miniature electronic components such as 1206 chip resistors and 1206 and 0603 chip capacitors. Unlike conventional wetting tests that use large solder baths, the micro-wetting method suppresses excessive solder rise, making it suitable for testing small-scale components. The results demonstrate that micro-wetting testing is a reliable method for evaluating solder wettability on chip components when appropriate globule size, test temperature, and experimental parameters such as immersion depth and speed are carefully controlled. Among the tested conditions, 2 mm diameter solder globules are identified as the optimal choice because they offer improved thermal management and reduced surface oxidation. The wetting times measured for SnBi58 are comparable to those obtained for conventional SAC305 solder, whereas the maximum wetting forces are generally lower. However, micro-wetting curves exhibit noticeable fluctuations, which complicate the analysis of additional parameters, such as maximum wetting force and wetting rate, and limit direct comparison with standard reference values. Full article

This study systematically investigates the influence of Bi content on the electromigration (EM) lifetime of low-temperature Cu/Sn-xBi-1Ag (600 μm)/Cu interconnects, where x = 57, 47 and 40 wt.%. The intrinsically higher product of diffusivity and effective charge number (DZ*) for Bi compared to Sn drives pronounced preferential migration of Bi atoms towards the anode, resulting in progressive β-Sn/Bi phase separation and linear thickening of a Bi-rich layer at the anode. Reducing the Bi content suppresses the EM-induced atomic flux (J_EM) through three principal mechanisms: (i) a decrease in the atomic concentration of mobile Bi atoms; (ii) a reduction in electrical resistivity that weakens the electron wind force; and (iii) an increase in lattice diffusion distance that lowers the effective diffusion coefficient (D_eff). The suppression of J_EM directly governs the thickening kinetics of anodic Bi layer, as evidenced by the close agreement between the calculated (1:0.40:0.23) and measured (1:0.45:0.26) anodic Bi layer growth rate ratios. Consequently, the EM lifetime is significantly extended from 62.3 h (Sn-57Bi-1Ag) to 164.9 h (Sn-47Bi-1Ag) and 414.1 h (Sn-40Bi-1Ag), representing 2.6-fold and 6.6-fold improvements, respectively. This study highlights that reducing the Bi content is an effective strategy for enhancing the EM reliability of Sn-Bi-Ag solder interconnects. Full article

Mt. Etna is the highest and most active stratovolcano in Europe, located in Catania (Sicily, Italy). Its persistent degassing, frequent explosions, and lava flows release large amounts of ash and gases into the atmosphere. This study aimed to assess whether chronic exposure to local volcanic emissions leads to an increased internal dose of trace elements (As, Ba, Be, Bi, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, Tl, U, V, W, Zn) in Catania adult residents. To this end, urine samples were collected from 167 individuals residing in Catania and compared with 193 residents of other Sicilian areas located farther from the volcano. Results revealed significantly higher urinary concentrations of As, Hg, Mn, Pb, and Tl in the exposed group, suggesting volcanic activity as a relevant source of exposure. The levels of the other elements were instead affected by other factors such as lifestyle habits and the consumption of specific foods and beverages. The urinary concentrations of trace elements were consistent with reference values reported in other European studies, and the levels remained well within the health-based guidance values. There is evidence of an increased internal dose of a few elements in the Sicilian population exposed to volcano activity, but the observed increases are unlikely to pose a significant health risk. Full article