Search Results (330)

Mineral exploration in the Iberian Pyrite Belt follows increasingly deeper targets. The present study introduces an innovative methodology for the detection and identification of blind metallic mineral deposits, in particular volcanogenic massive sulfides based on surface rock coatings. This approach follows the identification pathways of upward metal escape routes and metal distribution in rock fractures located in different anisotropic or isotropic planes above the Neves-Corvo VMS deposit ore lenses, using VP-SEM-EDS and XRD. Coatings are dominated by poorly crystalline to amorphous phases, with goethite and birnessite as the main Fe- and Mn-bearing minerals. Copper, zinc and lead are systematically enriched in coatings developed above or near the ore bodies, reflecting chalcopyrite, sphalerite and galena acidic leaching. Tin shows a restricted and heterogeneous distribution, while Ni and Co display no systematic relationship with the ore bodies. Barium and late Ba–Pb–(Zn) mineralization along fault zones record VMS mineralization. Lead isotopic coating signatures overlap those of IPB massive sulfide deposits, confirming a dominant VMS-derived contribution. Fe–Mn coatings were formed by precipitation from ascending meteoric fluids that leached metals from massive sulfides, their alteration halos, and surrounding lithologies, preserving the geochemical footprint of buried mineralization. This approach constitutes a new patented exploration tool. Full article

Thin-film solar cells (TFSCs) remain a cornerstone of the global transition toward renewable energy, characterized by consistent reductions in manufacturing costs and steady gains in power conversion efficiency. In addition to electricity generation, TFSCs play an important role in advanced solar thermal cooling, heating, and energy storage systems, where their tunable optical absorption, low thermal mass, and flexibility enable integration with photovoltaic–thermal (PV/T) collectors, thermally driven cooling cycles, and hybrid thermal–electrical storage architectures. This paper provides a comprehensive review of prominent TFSC technologies, including copper indium gallium selenide (CIGS), cadmium telluride (CdTe/CdS), amorphous silicon (a-Si), copper zinc tin sulfide (CZTS), organic photovoltaics (OPVs), and metal halide perovskite solar cells (PSCs), with a focus on their material structures, performance specifications, and current efficiency benchmarks. Compared to state-of-the-art reviews, this article distinguishes itself by addressing next-generation innovations, cross-domain solar thermal–photovoltaic applications, and economic analysis. Specifically, the integration of machine learning and simulation-based material dynamics is examined to accelerate material discovery, process optimization, and the characterization of novel TFPV components relevant to coupled thermal–electrical energy systems. Furthermore, the study explores how additive manufacturing is transforming the industry through the development of high-efficiency electrodes, electrohydrodynamic atomization for thin-film deposition, and the fabrication of flexible solar arrays suitable for thermally integrated and building-scale energy systems, including space applications. By integrating advancements in module efficiency, scalable manufacturing approaches, and techno-economic analysis, this paper positions TFSCs as sustainable, resource-abundant technologies essential for next-generation solar thermal cooling, heating, and energy storage infrastructures. Full article

The search for efficient photocatalysts for sustainable hydrogen production has driven growing interest in barium titanate (BaTiO₃)-based materials, particularly through polymorph control, surface engineering, and nonmetal and transition-metal doping. In this work, we provide an atomic-scale understanding of structural modifications in nitrogen-, fluorine-, and rhodium-doped BaTiO₃ using Density Functional Theory (DFT), as well as pristine and fluorine-substituted BaTiO₃ using reactive force-field molecular dynamics (ReaxFF-MD) simulations. DFT results for pristine and doped tetragonal BaTiO₃, as well as pristine hexagonal BaTiO₃, reveal that nitrogen and rhodium substitutions enhance the covalent character of Ti-N and Rh-O bonds and promote the redistribution of electron density, as evidenced by noncovalent interaction (NCI) and critical point (QTAIM) analyses, whereas fluorine substitution leads to more ionic Ti-F bonding. ReaxFF-MD simulations of pristine and fluorine-substituted BaTiO₃ in contact with water molecules demonstrate that fluorine substitution suppresses interfacial O-H bond formation and promotes ordered molecular hydration layers near titanium sites, as reflected in bond statistics and radial distribution functions. This study provides molecular insights into the role of N, F, and Rh doping in BaTiO₃ using DFT, and the role of fluorine doping in BaTiO₃ at the water–solid interface using ReaxFF-MD simulations, demonstrating that this integrated computational approach provides a solid basis for the rational design of next-generation materials for energy-related applications. Direct calculations of photocatalytic activity, charge transfer rates, and ferroelectric polarization effects were not performed in this work and remain important directions for future study. Full article

Flexible transparent conductive films (TCFs) and their applications have attracted extensive interest. Silver nanowires (AgNWs) have been explored to replace conventional indium tin oxide (ITO) due to their high optical transmittance and superior electrical conductivity. Nevertheless, AgNWs tend to oxidize under ambient conditions, which weakens the conductive network and limits long-term performance. Spraying reduced graphene oxide (rGO) can stabilize the conductive network and inhibit oxidation, thereby enhancing the overall properties of the films. In this work, rGO/AgNW/PET TCFs were prepared using a spray-coating approach. The transmittance of the rGO/AgNW/PET TCFs was measured at 77% at 550 nm, accompanied by a sheet resistance of 6.8 Ω/sq. The films achieved the surface temperature of 95 °C at 6 V with stable operation while also achieving an electromagnetic interference shielding effectiveness of 27 dB. This structural design improves both performance and stability, offering great potential for flexible TCFs in advanced optoelectronic applications. Full article

We investigate the effects of post-annealing in oxygen (O₂) and nitrogen (N₂) on tin-doped vanadium oxide (V_xSn_yO_z) films for microbolometer applications. The films were deposited using magnetron sputtering in an Ar:O₂ environment. We demonstrate that low Sn doping combined with N₂ post-annealing provides an effective approach to optimize the temperature coefficient of resistance (TCR), resistivity, and 1/f-noise. Compared to undoped VO_x, V_xSn_yO_z films exhibit an enhanced TCR, moderate resistivity, and reduced 1/f-noise. The 135 nm thick V_0.46Sn_0.03O_0.51 film after post-annealing in N₂ shows a TCR of −4.08%/K and a resistivity of 7.3 × 10⁻² Ω⋅cm at 300 K, an absorptance of 63–68% in the 900–2500 nm wavelength range, and low noise voltage power spectral density (1.77 × 10⁻¹⁶ V²/Hz at 100 Hz under 0.3μA bias current). These results indicate that Sn-doped VO_x films are promising sensing materials for microbolometer applications. Full article

Tool wear remains a critical limiting factor in machining performance, particularly in dry cutting conditions where friction and tribological interactions dominate. This study investigates the influence of a 5–8 μm PVD-deposited TiN coating on the wear behavior of high-speed steel (HSS) end mills during milling of three representative wood species (oak, beech, and fir). A spatially resolved wear evaluation methodology was employed, based on ten measurement points distributed along a 20 mm active cutting edge, enabling simultaneous assessment of mean wear and maximum localized wear (Umax). A factorial experimental design combining material type and feed rate (1500–2500 mm/min) was analyzed using two-way ANOVA with effect size quantification (η²). The results reveal a statistically significant reduction in mean wear for TiN-coated tools (F = 7.46, p = 0.0195, η² = 0.34), corresponding to an average decrease of approximately 46% compared to uncoated tools. Maximum wear was influenced by both coating (F = 14.73, p = 0.0028, η² = 0.399) and material (F = 4.37, p = 0.040, η² = 0.237). The experimental findings are interpreted through a tribological framework, indicating a transition from abrasion- and micro-chipping-dominated degradation in uncoated tools to a controlled wear regime in TiN-coated tools, characterized by reduced asperity penetration, delayed crack initiation, and limited tribochemical interactions. These results demonstrate that coating effects dominate global wear evolution, while material properties influence localized degradation. The proposed combined experimental–statistical–mechanistic approach provides a robust framework for understanding and optimizing tool performance in dry machining environments. Full article

Indium Tin Oxide (ITO) is one of the most widely used ohmic materials for fabricating ohmic layers in thin-film solar cells. ITO thin layers have reached almost the maximum theoretical conductivity and the lowest practical resistivity. Along with indium’s toxic environmental impact and the high cost of materials, these are the reasons why new materials for efficient, cheaper thin-film transparent ohmic layers are being examined. One of those materials is copper-doped zinc oxide (ZnO:Cu). In this paper, we present a new approach to copper-doped zinc oxide fabrication methods, based on the modern authorial Physical Vapor Co-Deposition technique, which involves optimizing Cu concentration to fine-tune crystal structure, optical band gap, and electrical properties, creating n-type TCOs essential for efficient charge transport in next-generation thin films perovskite solar cells. Full article

Metal-chalcogenide compounds with perovskite-type compositions have drawn increasing attention for their optical properties for solar energy conversion. Herein, a new α-type polymorph of the ternary sulfide SrHfS₃ is described, crystallizing in the NH₄CdCl₃ structure type. The yellow-colored plate-shaped crystals were synthesized at 1173 K using an elemental tin flux in an evacuated sealed tube. Its crystal structure was characterized at room temperature using single crystal X-ray diffraction to form in the orthorhombic Pnma space group, with the refined cell parameters of a = 8.5041(4) Å, b = 3.8004(2) Å, c = 13.8935(6) Å, and V = 449.02(4) ų. The structure comprises five independent crystallographic sites, having one Sr, one Hf, and three S sites. The structure can be described as containing one-dimensional chains of distorted HfS₆ octahedra extending down the b-axis to form ${\displaystyle \genfrac{}{}{0pt}{}{1}{\infty }}[$HfS₃]²⁻ strips of edge-sharing octahedra. The Sr atoms act as charge-balancing space fillers in the structure. High-purity bulk samples of α-SrHfS₃ could be prepared for measurement of its bandgap by optical diffuse-reflectance spectroscopy, showing a direct bandgap of 2.1(1) eV. Results of electronic structure calculations are consistent with this bandgap and type. The conduction and valence band edges stem from the respective empty Hf d-orbitals and the filled S p-orbital states. In summary, crystal growth of the α-type polymorph of SrHfS₃ has been demonstrated using a Sn flux approach, which can facilitate future broader synthetic explorations at lower temperatures. Full article

Electrochromic devices have emerged as promising candidates for non-emissive displays due to their particular photoelectric performance in complex lighting environments. They exhibit considerable potential in emerging fields such as Internet of Things terminals, flexible wearables and human–computer interaction interfaces. In this study, we developed a low-power electrochromic display based on a Pt/FTO (Fluorine doped tin oxide) electrocatalytic counter electrode and a Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) porous gel electrolyte. The Pt catalyst enhances Br⁻/Br³⁻ redox reactivity, which reduces the driving voltage from 2 V to 1 V, and accelerates the electrode reaction kinetics. It is systematically explained by the Density Functional Theory (DFT) calculations and electrochemical characterization. Furthermore, we demonstrate a proof-of-concept multicolor display incorporating the electrocatalytic counter electrode with various viologen derivatives. This approach provides a significant advancement toward next-generation high-performance displays and is supportive of the development of energy-efficient optoelectronic devices. Full article

The electrochemical reduction of CO₂ offers a sustainable approach to transforming carbon dioxide into value-added products when powered by renewable energy. However, current electrocatalysts lack efficiency and selectivity, hindering commercial application. Combining tin’s high formate selectivity with copper’s ability to reduce CO₂ via COOH* pathway offers a promising strategy. This synergy mitigates copper’s low selectivity, providing a cost-effective catalyst with enhanced performance over pure Sn-based systems. This work investigates CuSn bimetallic electrocatalysts synthesised by scalable electrodeposition onto gas diffusion layers to boost formate production. Catalytic performance and cell potential were evaluated at current densities ranging from 50 to 200 mA cm⁻² and varying Sn compositions. Catalysts with Sn content below 4% predominantly formed CO and H₂, but smaller particles and improved metal dispersion increased formate production. A catalyst containing 12% Sn achieved a maximum faradaic efficiency (FE) of 52% at 50 mA cm⁻² with an iR-corrected potential of −0.56 V vs. SHE. At 200 mA cm⁻², it exhibited a 30% FE for formate, along with 31% FE for CO and 9.3% FE for H₂, while other gases contributed to less than 4% FE, indicating potential as syngas feedstock. Higher Sn content, combined with smaller, well-distributed particles, effectively suppressed H₂, CO, and other by-products, highlighting a strong dependence of FE on Sn content and bimetallic distribution, demonstrating compositional tuning importance via electrodeposition. Full article

The food system of Zhejiang Province, a major coastal province in China, includes a wide variety of products, such as canned foods, aquatic products, vegetables, fruits, and tea, all of which may serve as potential sources of tin (Sn) exposure. However, no systematic study has assessed the distribution and dietary exposure risk of Sn across food categories in the province, and a compound-specific evaluation of organotin compounds is lacking. Therefore, we investigated the occurrence of Sn in commonly consumed foods and assessed dietary exposure risks among different age groups in Zhejiang Province. In total, 2014 samples from five major food categories—fresh vegetables, fresh fruits, tea, fresh aquatic products, and canned foods—were collected using a multistage stratified random sampling strategy. The Sn concentrations were measured using inductively coupled plasma mass spectrometry, with non-detection replaced by half the detection limit. Dietary intake data were derived from the 2015–2017 Nutrition and Health Surveillance using a 3-day, 24 h recall. The estimated daily intake and total hazard quotient (THQ) were calculated for age-specific risk assessments under multiple exposure scenarios. Fresh vegetables, fruits, tea, and most aquatic products had low Sn concentrations, whereas canned foods, particularly fruits, fungi, and meat products, had higher Sn concentrations. THQ values remained well below 1 across all food categories, indicating minimal health risks under typical consumption patterns, although lifetime exposure estimates suggested that canned foods could approach toxicological benchmarks earlier under high-consumption scenarios. A supplementary assessment of organotin compounds, which are highly toxic even at low fractions of total Sn, used a reverse dietary risk approach and probabilistic modeling. Canned foods and fresh aquatic products exhibited the lowest minimum conversion rates (0.16% and 0.37%, respectively), indicating that they are the most susceptible to organotin risk, whereas fresh fruits (7.77%) and tea (18.67%) required much higher proportions. Due to limited literature, further scenario- and probabilistic-based assessments focused on fresh aquatic products, revealing that typical exposure levels are generally safe, but children ≤ 6 years of age are the most vulnerable. Although overall Sn exposure is low, intake of highly processed foods, particularly canned products, should be limited in young children’s diets. These findings highlight that even small shifts in Sn speciation within high-risk food categories can lead to excessive tolerable daily intakes. This study provides a scientific reference for dietary Sn risk assessment and food safety management. Full article

Cold forging backward extrusion is mainly employed in the manufacturing of axisymmetric cup-like components used extensively in automotive and aerospace assemblies due to the process-induced strength that has a pivotal role in such applications. Although cold forging backward extrusion yields mechanically robust components, it demands high forces, subjecting tooling to immense stress, thereby restricting process capacity. The process encounters hindrances in gaining widespread industrial acceptance due to frequent failures of die elements, necessitating proper die design and control of major influencing factors for process viability and cost-effectiveness. The punches in backward extrusion are often susceptible to failures when processing steel billets. The punch service life is significantly affected by geometrical attributes, the type of steel undergoing deformation, and tool manufacturing aspects. Hence, the present study evaluates punch performance in cold forging backward extrusion using optimized geometrical attributes, manufactured through a design of an experimental approach comprising an L9 orthogonal array. The manufacturing factors considered are punch material, hardness, and advanced surface coating. Punches were designed for two industrial components using powder metallurgy (PM) steels—S600, S290, and S590, heat treated to 60–66 HRC, and coated via physical vapor deposition with TiN, AlTiN, and TiAlCN. Punch performance was analyzed against existing industry practices, and the strategy demonstrated improved productivity. Punch performance was determined based on the number of forgings produced before wear- and fatigue-induced failures. Significant improvements in punch performance were witnessed in both high-speed steel (HSS) and PM punches with optimized geometries. Fractographic investigations were carried out on fractured punches and analyzed, focusing on the coating’s effect on the thermal aspects of the punches. The proposed study will assist the cold-forging industry in determining appropriate variables to minimize forming responses, thereby enhancing tool life. The research also benefits industries by enhancing process robustness and improving process efficiency with respect to cost and time. Full article

Optical-based sensors have been widely used for various applications, including biosensing, civil structural health monitoring, and humidity sensing. Fiber Bragg Grating (FBG) is one of the optical-based sensing approaches that are commonly used in these applications. The effect of hygroscopic coating on different grating profiles, including uniform, apodized, and tilted FBG, was investigated by connecting the FBG to a light source and optical spectrum analyzer (OSA). The reflected wavelength of the FBG, captured by the OSA at increasing and decreasing relative humidity ranging from 40 to 80% RH were recorded. Tin dioxide (SnO₂) is one of the metal oxides with a hygroscopic nature, which is suitable to act as a coating material for FBG. For improved sensitivity, the HMT-enhanced technique was applied in this study to modify the surface morphology of SnO₂, increasing the porosity of the nanostructure for water adsorption and desorption. The result showed that the sensitivity and linearity of the FBG-based humidity sensor can be enhanced via HMT-enhanced SnO₂ nanostructure coating onto uniform FBG. A sensitivity of 1.30 pm/%RH and 1.52 pm/%RH was reported during incremental and decremental RH, respectively, and a fitting coefficient of >0.97 was recorded. This approach demonstrated the feasibility of hygroscopic coating on FBG to enable broad applications across various humidity sensing industries such as agriculture, pharmaceutical, and semiconductors. Full article

To address the issues of parameter setting, reliance on human experience, and the limitations of traditional model-driven control methods in handling complex nonlinear dynamics in the tin smelting industrial process, this paper proposes a data-driven control approach based on improved deep reinforcement learning (RL). Aiming to reduce the tin entrainment rate in smelting slag and CO emissions in exhaust gas, we construct a data-driven environment model with an 8-dimensional state space (including furnace temperature, pressure, gas composition, etc.) and an 8-dimensional action space (including lance parameters such as material flow, oxygen content, backpressure, etc.). We innovatively design a Dual-Action Discriminative Deep Deterministic Policy Gradient (DADDPG) algorithm. This method employs an online Actor network to simultaneously generate deterministic and exploratory random actions, with the Critic network selecting high-value actions for execution, consistently enhancing policy exploration efficiency. Combined with a composite reward function (integrating real-time Sn/CO content, their variations, and continuous penalty mechanisms for safety constraints), the approach achieves multi-objective dynamic optimization. Experiments based on real tin smelting production line data validate the environment model, with results demonstrating that the tin content in slag is reduced to between 3.5% and 4%, and CO content in exhaust gas is decreased to between 2000 and 2700 ppm. Full article

In this study, we investigated the bioaccumulation of 17 heavy metals—titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, antimony, cadmium, tin, mercury, and lead—in the liver and kidney tissues of the least weasel, based on samples (n = 129) collected from adjacent intensive agricultural environments in Hungary and Austria. To explore the structure of the bioaccumulation data, principal component analysis (PCA) was performed. The PCA score plot based on national-level elemental profiles revealed no differentiation between Austria and Hungary. In contrast, a clear and unambiguous distinction was observed between the two examined tissues within individuals for Ti, Mn, Fe, Co, Zn, Se, Mo, Cd, and Hg (p < 0.001), as well as for Pb (p < 0.05). The biological relevance of the accumulation results was adjusted using the MCID approach. As heavy metal accumulation in the least weasel has not yet been investigated, our results could only be compared with concentrations reported for predatory mammals occurring in similar habitats. Based on the relevant literature, we highlight predominantly anthropogenic exposure pathways affecting agroecosystems—organic and mineral fertilizers, plant protection products, wastewater, and fossil fuels—which underscore the necessity of regular biomonitoring studies in agricultural landscapes. Full article