Search Results (1,349)

This study evaluated the storage stability of tomato juice, paste, and purée packaged in conventional aluminium containers (ACs) and aluminium containers coated with a food-grade stainless steel layer (ASSCs). The objective was to determine whether the stainless steel coating could reduce aluminium ion migration, preserve the physicochemical and nutritional quality of tomato products during storage, and decrease the need for antioxidant, antifungal, and acidifying additives. The stainless steel coating improved the barrier performance of the Al substrate by reducing its porosity from 6.0% to 3.8%. During storage, tomato products in ACs exhibited a marked decrease in acidity (7.65–4.07 g/100 g), whereas samples stored in ASSCs showed a smaller reduction (7.65–5.98 g/100 g), indicating enhanced chemical stability. Increasing NaCl concentrations promoted Al migration, reaching 26.4 mg/kg in AC but only 9.2 mg/kg in ASSC. The vitamin C content remained nearly unchanged (2.09–2.04 mg/100 g), while total polyphenols decreased slightly (110.13–98.81 mg/100 g). Mineral analysis (Al, Cr, Mn, Ni, Zn, Fe, and Ca) confirmed higher metal concentrations in AC-stored samples, whereas aluminium migration was effectively minimised in ASSCs. These findings demonstrate that stainless steel-coated aluminium provides superior corrosion resistance, limits metal transfer, preserves the physicochemical and antioxidant quality of the tomato products, and represents a promising packaging material for extending shelf life while reducing the need for food additives. Full article

Zn-Al-Mg (ZAM) coatings have attracted significant attention in the field of corrosion protection owing to their combination of excellent corrosion resistance and cost-effectiveness. However, the corrosion behavior of ZAM coatings was governed by the synergistic coupling effects of multiple factors, including alloy composition, coating thickness, corrosive medium, and multiphase microstructure, making it challenging for traditional empirical analysis to systematically reveal the underlying mechanisms. To address this challenge, we constructed a multidimensional corrosion dataset comprising alloy composition, corrosive medium, coating thickness, and phase composition, based on literature data from the past three decades combined with self-measured potentiodynamic polarization experimental results. After data normalization and correlation analysis, we introduced phase structure features—including the Al-rich phase, MgZn₂ phase, Mg₂Si phase, and eutectic microstructures—to enhance the model’s capability in representing microstructural factors. On this basis, we established random forest (RF), support vector regression (SVR), and artificial neural network (ANN) models to predict the corrosion current density, and subsequently conducted an interpretability analysis using the SHapley Additive exPlanations (SHAP) method. The results demonstrated that the expanded feature set significantly improved the prediction performance of the models. Among them, the RF model exhibited the best performance, achieving a determination coefficient (R²) of 0.7363 on the test set, which represented a substantial improvement over the baseline dataset. Feature importance analysis revealed that coating thickness, Mg content, NaCl concentration, and Zn content were the primary factors influencing the corrosion current density. Further SHAP analysis showed that the marginal contribution of the eutectic phase was more prominent in local samples. Meanwhile, the Mg element exhibited distinct non-linear regulation characteristics, exerting varying impacts on the corrosion behavior across different concentration ranges. This study demonstrated that the interpretable machine learning models constructed via feature engineering not only improved the prediction accuracy of the corrosion performance of ZAM coatings, but also provided a novel data-driven approach to revealing the intrinsic correlations among alloy composition, phase structure, and corrosion response. Full article

Juniperus species form critical, long-lived high-mountain forest ecosystems in Central Asia, serving essential phytocoenotic and ecological functions in environmentally challenging habitats. However, the relationships between the elemental composition of these evergreen conifers and their underlying soils remain poorly understood. This study evaluated and compared the distribution of major elements (Fe, Ca, P, Mg, Al, Na, K, S), trace elements (Cu, Pb, Zn, Ni, Co, Mn, As, Cd, Cr, Mo, U, Th, Sr, Sb, Bi, V, La, Ba, Ti, B, W, Sc, Zr, Tl, Ta, Nb, Se, Te, Ga, Cs, Ge, Hf, Rb, Sn and others), and environmental pollution indices (Igeo, EF, CF, BAF) in plant tissues (leaves and cones) and canopy soils of three key juniper species (Juniperus seravschanica, J. turkestanica, and J. semiglobosa) in the Fann Mountains, Tajikistan. Soil and plant samples were collected across natural habitats and analyzed for total chemical composition using ICP-OES. The soils showed a near-neutral reaction (pH 7.02–7.42 in H₂O and 6.41–7.15 in KCl), with considerable variability in Corg. content (5.04%–21.82%) and Nt content (0.337%–1.149%) in the humus (A) horizons. Geochemical indices (Igeo up to 2.42, EF up to 35.30) indicated noticeable soil enrichment and localized contamination by arsenic (As) and cadmium (Cd), likely driven by a combination of regional industrial and mining activities alongside natural geogenic enrichment. Across all sites, elemental concentrations followed a consistent sequence: soil > leaves ≈ cones. Heavy metals in plant tissues remained well below toxic thresholds. High organ-specific partitioning was observed: K predominated in cones (K > Ca > P), whereas Ca and Fe accumulated predominantly in leaves (Ca > K). Low bioaccumulation factor values (BAF < 1) indicate limited element accumulation relative to total soil concentrations for all three species, which may be influenced by both reduced bioavailability in neutral-to-alkaline soils and potential physiological regulation. As the first data reported from this region, these findings establish an essential baseline for long-term ecological monitoring, soil–plant chemistry, conservation, and environmental risk assessment in the Fann Mountains’ juniper ecosystems. Full article

In this work, we systematically investigate the effects of metal doping on the structural, electrical, and optical properties of spin-coated nanocrystalline ZnO thin films prepared by a simple acetate-based solution process. The incorporation of different metal dopants significantly modified the crystallographic, electrical, and photoluminescence properties of ZnO. Doping with alkali metals enhanced the photoluminescence efficiency and enabled amplified spontaneous emission, whereas Mg was the only dopant that produced a pronounced blue shift in the photoluminescence spectra. Lithium-doped ZnO exhibited a strong concentration-dependent electrical behavior, producing highly conductive n-type ZnO at a 1% doping level and p-type conductivity at an 8% concentration. Strong n-type conductivity was also achieved using low concentrations of Li and Na and higher concentrations of Al. In contrast, Fe-, Ni-, Cu-, and Pb-doped ZnO exhibited a substantial reduction in electrical conductivity accompanied by strong photoluminescence quenching, indicating enhanced defect-related carrier compensation. These results demonstrate that metal doping provides an effective approach for tailoring the structural, optical, and electrical properties of ZnO and offers a versatile route toward engineering ZnO-based layers for optoelectronic devices, transparent conductive contacts, photodetectors, solar cells, and ultraviolet laser applications. Full article

Uranium separation from aqueous media remains a critical challenge at the intersection of nuclear fuel cycle efficiency and environmental safety. Layered double hydroxides (LDHs) are promising adsorbents for U(VI) removal and serve as versatile inorganic matrices for the design of nanocomposite sorbents. However, the influence of their key structural parameter, Me²⁺/Me³⁺ cationic ratio, on sorption performance and composite functionality remains insufficiently explored. This study investigates how the Zn^2+/Al³⁺ ratio governs the structure, sorption kinetics, and U(VI) uptake mechanisms of Zn-Al LDH. Characterization by XRD, TEM, XPS, XAFS, cryogenic laser-induced fluorescence spectroscopy, Raman, and positron annihilation spectroscopy revealed that increasing Al³⁺ content up to the optimal ratio of 2/1 enhances sorption capacity through increased positive charge density, reaching maximum static (47.2 mg/g) and dynamic (17.05 mg/g) capacities. EXAFS and fluorescence spectroscopy demonstrate that U(VI) adsorption at pH 4.0 proceeds via inner-sphere complexation involving mononuclear uranyl carbonate/hydroxyl species (UO₂(CO₃)₂²⁻, UO₂(CO₃)₃⁴⁻, UO₂(OH)_n⁽²⁻ⁿ⁾) and polynuclear complexes, predominantly (UO₂)₂(CO₃)(OH)₃⁻. Further increase to Zn/Al = 1/1 induced mesopore narrowing and inhibited diffusion, drastically decreasing dynamic performance. These findings establish the Zn/Al ratio as a key parameter governing LDH sorption efficiency and provide a mechanistic basis for the rational design of LDH-based composite sorbents. Full article

Germanium is a critical rare-dispersed metal with irreplaceable applications in infrared optics, fiber-optic communications, and semiconductor industries, making its efficient recovery from secondary resources of great strategic importance. This study investigates the selective recovery of germanium from complex zinc smelting leachates using a novel hydroxamic acid extractant, BGYW, in synergistic combination with P204. The feed solution contained approximately 360 mg/L Ge, 10,790 mg/L Fe²⁺, and 98,530 mg/L Zn, representing a highly complex matrix. Continuous counter-current extraction was performed in a 30-stage miniature mixer-settler. Under optimized conditions of 10% BGYW + 5% P204 in white oil, an O/A ratio of 1:1, and 8 mol/L NH₄F as strippant, the single-stage germanium extraction efficiency reached 99.4%. Over 16 consecutive cycles, the extraction system maintained stable performance with average germanium extraction above 99%. A 3-stage scrubbing section using 50 g/L H₂SO₄ effectively removed co-extracted Zn, Cu, and Al impurities. Iron co-extraction, a major challenge, was successfully mitigated through a 2–3 stage iron scrubbing step using a chloride-containing scrubbing solution, which reduced the iron concentration in the strip liquor from approximately 600 mg/L to below 4 mg/L, and decreased the Fe/Ge mass ratio from 0.197 to below 0.01. The overall germanium recovery across the entire 30-stage continuous process reached 98.82%, and the dissolution loss of BGYW in the aqueous phase was reduced by over 85% compared to the conventional YW100 extractant. Third-phase formation caused by residual organic flocculants from the leaching step was eliminated through enhanced pre-treatment, while ferric fluoride precipitation in the stripping section was resolved by incorporating the iron scrubbing stage. This study demonstrates that the BGYW-P204 extraction system with the integrated iron scrubbing step offers an efficient, stable, and industrially viable approach for germanium recovery from zinc smelting leachates, providing a practical solution to the long-standing challenge of germanium–iron separation and contributing to the sustainable supply of this critical metal. Full article

Trace element contamination represents a persistent environmental issue, particularly in industrialized areas where anthropogenic emissions overlap with natural geochemical backgrounds. This study investigates the atmospheric deposition of trace elements in the Milazzo district (Italy), which is characterized by intense industrial activity. Pinus pinea L. needles were used as biomonitors to assess the spatial distribution and sources of trace elements, combined with lead isotopic analysis for source apportionment. Forty needle samples were analyzed by ICP-OES and ICP-MS for Ca, K, Mg, Na, P, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Ti, V, Zn, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, while 25 samples were selected for Pb isotope ratio determination (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb). Multivariate statistical analyses identified source groups related to industrial and petrochemical emissions, vehicular traffic, crustal resuspension, and mixed combustion processes. Elevated concentrations of As, Cr, Mo, Ni, Pb, Sb, V, and Zn ranged from 16.6 μg g⁻¹ (Zn) to 0.09 μg g⁻¹ (Sb), with the following order of abundance: Zn > Cr > Ni > Pb > Mo > V > As > Sb; these elements were found near industrial facilities and urban areas. Enrichment Factor calculations indicated strong anthropogenic contributions to Cd, Cu, Mo, Sb, V, and Zn, with EF > 10, ranging from 10 (Cd) to 60 (Zn), whereas Al, Fe, and Ti exhibited EF values between 0.5 and 2, reflecting geogenic origins. Pb isotopic ratios (²⁰⁶Pb/²⁰⁷Pb = 1.153–1.192 and ²⁰⁸Pb/²⁰⁶Pb = 2.063–2.108) revealed mixing between industrial emissions and the local geological background, with limited influence from historical gasoline-derived Pb. This integrated geochemical and isotopic approach can effectively identify contamination sources in complex industrial environments. Full article

Phosphorus is recognized as one of the primary contributors to eutrophication in freshwater ecosystems. Among the various strategies proposed to mitigate its impact, adsorption-based removal has emerged as one of the most widely adopted and effective approaches globally. In this study, Zn/Al-layered double hydroxides (LDHs) were synthesized by varying the molar ratio of cations to obtain materials with different cationic densities. The materials were additionally modified via a co-precipitation method to incorporate titanium dioxide (TiO₂) or zinc oxide (ZnO) nanoparticles to synthesize novel composite nanomaterials aimed at phosphate species removal from aqueous solutions. The resulting materials demonstrated orthophosphate adsorption capacities exceeding 45 mg/g in most cases. Adsorption kinetics were evaluated using pseudo-first order and pseudo-second order models, while equilibrium data were fit to the Langmuir and Freundlich isotherms. The results indicated that the pseudo-second order model and the Langmuir isotherm provided the best fit, suggesting that the adsorption process is predominantly chemisorption occurring on a homogeneous monolayer. These findings highlight the potential of TiO₂/ZnO–LDH composites as efficient adsorbents for phosphorus remediation in aquatic environments. Full article

The interfacial reaction between solder and substrate is a critical factor governing joint reliability, making it essential to understand the formation and stability of interfacial reaction layers when developing new high-temperature lead-free solders. This study investigates the interfacial reaction layers formed in Zn-5Al-3Mg solder/Cu substrate joints soldered at 693 K under vacuum. With a binary Zn-Al solder, the Cu substrate is progressively consumed by Zn, and the intermediate phases CuZn₄, Cu₅Zn₈, and CuZn nucleate and grow concurrently at the solder interface. The addition of a minor amount of Mg to the Zn-Al alloy, however, fundamentally alters this reaction sequence. Transmission electron microscopy analyses, including scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy (STEM-EDS), energy-filtered TEM (EF-TEM), and electron diffraction, reveal three distinct interfacial layers: an outer Mg₂Zn₁₁ layer, a middle two-phase mixture of CuZn₄/Mg₂CuZn₃, and an inner Cu₅Zn₈ layer adjacent to the Cu substrate. The biphasic CuZn₄/Mg₂CuZn₃ mixture layer is shown to form via a quasi-peritectic reaction governed by sequential four-phase equilibria in the Zn-Mg-Cu ternary system. These findings demonstrate that minor Mg additions redirect the interfacial reaction pathway between Zn-Al-based solders and Cu substrates, providing new insight for the design of high-temperature Pb-free solder systems. Full article

The aim of this work is to investigate the influence of different welding technologies on the mechanical properties and corrosion resistance of welded joints of SGH340D + ZMA steel with a Zn–Mg–Al (ZMA) protective coating. Two different welding technologies were used: the gas metal arc welding(GMAW) process at a welding speed of 0.8 m/min and laser welding at speeds of 2 and 4 m/min. Mechanical properties were determined using tensile testing and hardness testing. Corrosion resistance was estimated using a salt spray test. Residual stresses were determined experimentally using the drill hole method. The highest residual stresses were measured in GMAW-welded joints, while the lowest were measured in laser-welded joints at a speed of 4 m/min. The sample welded by laser at a speed of 4 m/min exhibited hardness values close to the upper acceptable limit, indicating that further increases in welding speed without preheating may lead to excessive hardness. All samples exhibited good corrosion resistance in a salt chamber. According to the results, increased welding speed reduced residual stresses but increased the risk of brittle fracture. Full article

A mass action concentration model of FeO-Fe₂O₃-SiO₂-CaO-MgO-Al₂O₃-ZnO multi-component slag was established to address the problems of high viscosity and high copper content in oxygen-enriched top-blown copper smelting slag. Theoretical calculations, combined with experimental investigations, were performed to evaluate the effects of ZnO additions (0–25 wt.%) on phase transformation, Fe₃O₄ reduction and copper content in the slag at temperatures ranging from 1200 to 1400 °C. The results indicate that ZnO addition decreases the mass concentrations of Fe₂O₃, Fe₃O₄, Fe₂SiO₄ and SiO₂, while increasing the proportions of zinc-bearing structural units and enhancing the reducing capability of the slag. In the copper slag system, Zn²⁺ substitutes for Fe in Fe₃O₄ and Fe₂SiO₄ through isomorphous substitution, forming Fe-Zn spinel and Fe-Zn olivine. As the addition of ZnO gradually increases to 25 wt.%, the liquid slag fraction increases and the slag viscosity decreases, resulting in a reduction in copper content from 5.64 wt.% to 2.04 wt.%. Furthermore, ZnO promotes the transformation of Fe₃O₄ into zinc–iron spinel, which is more readily reducible by carbothermic reaction than Fe₃O₄ itself, thereby facilitating the overall reduction of iron oxides in the copper slag. These findings provide a theoretical basis for slag-type regulation and the efficient separation of copper from slag via high-temperature gravity settling of matte. Full article

The role of the Zn/Mg ratio in regulating microstructure, precipitation evolution and coarsening resistance in Al–Zn–Mg-based alloys was investigated by microhardness testing, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) during isothermal aging at 150 °C. Three alloy compositions were designed with Zn/Mg ratios of 1.6, 2.4, and 3.9, whereas the combined Zn and Mg level was fixed at 6.0 wt%. All alloys exhibited a typical age-hardening response, whereas the maximum peak hardness was obtained at an intermediate Zn/Mg level rather than at the two extremes. The optimal composition (Zn/Mg = 2.4) reached 137 HV, which is attributable to the formation of the finest precipitates (~3 nm) and the highest number density. Moreover, this alloy exhibited the smallest hardness loss (ΔH = 19 HV) after prolonged aging (192 h). TEM analysis indicated that this alloy exhibited the lowest coarsening rate constant, Kr = 0.43 at 192 h. Furthermore, the variation in Zn/Mg ratio affected grain boundary precipitation, leading to a minimized PFZ width at Zn/Mg = 2.4 while maintaining a similar discontinuous distribution of grain boundary precipitates among the alloys. Overall, tailoring the Zn/Mg balance offers an effective strategy to achieve refined precipitates, improved coarsening resistance, and enhanced mechanical performance with superior thermal stability. Full article

Layered double hydroxides (LDHs) are functional materials with tunable structural, surface, and adsorption properties. In this study, multicationic LDHs were synthesised and evaluated as adsorbents for chromate(VI). Among the investigated materials, the tetracationic Mg₂Cu_0.5Zn_0.5Al₁ composition exhibited consistently high mass-normalised Cr(VI) uptake in the screening experiments and was therefore selected for detailed investigation. Therefore, its chloride and carbonate forms were selected as model materials to examine the role of interlayer anions in Cr(VI) uptake and pH-dependent stability. The chloride form exhibited a higher adsorption capacity (70 mg/g) than the carbonate form (34 mg/g), indicating that more weakly bound interlayer anions may increase the accessibility of adsorption sites and promote anion exchange during adsorption. In contrast, the carbonate form showed greater structural stability, as confirmed by reduced cation leaching over a wide pH range. The behaviour of Cr(VI) in equilibrium solution was analysed as a function of its initial concentration, which allowed a simple description of Cr(VI) sorption over a wide range of initial pH values. XRD, FTIR, and XPS analyses supported partial interlayer anion exchange and changes in the coordination environment of surface metal centres after Cr(VI) sorption. Adsorption energies of 13–16.4 kJ/mol further suggested that Cr(VI) uptake cannot be assigned to a single interaction type but involves electrostatic interactions, anion exchange, and surface complexation. These results demonstrate that the interlayer anion is a key factor governing both the Cr(VI) adsorption efficiency and aqueous stability of LDH-based adsorbents. Full article

The corrosion behavior of symmetric (S-joint) and asymmetric (A-joint) double-sided friction stir-welded (DS-FSW) 7A65 aluminum alloy thick plates was investigated in 3.5 wt% NaCl solution. The S-joint, produced using the same large tool (Φ30 mm) for both passes, imposes two high-heat thermal cycles that result in insufficiently fragmented intermetallic particles (IMPs), coarse grains, and severely overaged heat-affected zones (HAZs). In contrast, the A-joint, employing a smaller tool (Φ24 mm) for the second pass, reduces the total heat input and achieves a refined microstructure with fine (2–3 µm), rounded IMPs in the second-pass weld nugget (WNZ-S) and less degraded HAZs. Electrochemical measurements reveal that the HAZ-Overlap (HAZ-O) is the most anodic zone in both joints. The S-joint shows a larger potential spread (up to ~120 mV) and higher corrosion current density than the A-joint. The hierarchical galvanic coupling, where macro-galvanic corrosion between the anodic HAZ-O and cathodic WNZs drives severe localized attack, while micro-galvanic corrosion around coarse IMPs initiates trenching, is elucidated. The A-joint mitigates this damage due to its reduced galvanic driving force (smaller potential spread of ~74 mV) and improved microstructural homogeneity. The enhanced corrosion resistance of the A-joint is attributed to grain refinement, effective IMP fragmentation, and a less degraded HAZ microstructure. Full article

This study develops novel multicomponent Al–Mg–Si–Zr–Cu-based alloys for high-pressure die casting (HPDC) with improved mechanical properties and thermal stability. Four compositions were designed through Zn and Cr additions, supported by thermodynamic modelling. XRD and SEM/EDS analysed phase formation and microstructure, while density, electrical conductivity, hardness, and mechanical behaviour under tensile and compressive loading at room temperature and 200 °C were evaluated. Hardness increased from 166 to 214 HV3 with Zn and Cr due to the formation of complex intermetallic phases. The Al–Mg–Si–Zr–Cu alloy showed the best balance of strength and ductility under tensile loading, whereas Zn and Cr additions reduced tensile performance. In compression, Zn significantly improved strength, reaching the ultimate compressive strength of 697 MPa. Compared with the reference AlSi9Cu3 alloy, the new alloys achieved up to 30% higher yield strength, 13% higher ultimate tensile strength, and improved thermal stability. Among the studied compositions, Al72Mg10Si5Zr3Cu10 showed the best overall performance, while Al67Mg10Si5Zr3Cu10Zn10 was optimal for compression-dominated applications. Full article