Search Results (1,275)

Samples of flotation tailings generated during the exploitation and processing of Zn–Pb–Cu–Ag ore from the Rudnik mine (Serbia) were investigated for their mineralogical, geochemical, and magnetic susceptibility properties. The flotation tailings consist of a complex mineral assemblage, including silicates, carbonates, sulfides, phosphates, sulfates, oxides, hydroxides, and native elements. Quartz, calcite, and orthoclase dominate the coarse fraction (>400 µm), accompanied by epidote, Ca-garnet, and Ca-clinopyroxene. Sulfide minerals are concentrated in finer fractions (<400 µm), with pyrite and arsenopyrite being the most abundant, followed by pyrrhotite, sphalerite, galena, and chalcopyrite. These sulfides occur as dispersed grains within a silicate–carbonate matrix. Post-depositional oxidative alteration is moderately developed, with pyrite replaced by hematite, galena by cerussite, and chalcopyrite by malachite. Geochemical analyses reveal that SiO₂ (avg. 38.98 wt%), Fe₂O₃ (avg. 23.68 wt%), Al₂O₃ (avg. 8.95 wt%), CaO (avg. 9.03 wt%) and MgO (avg. 1.50 wt%) dominate the composition. Economically significant metals include Zn (avg. 0.47 wt%), Pb (avg. 0.20 wt%), Cu (avg. 0.11 wt%), Ag (max. 19 µg/g), and Bi (max. 130 µg/g). Mass magnetic susceptibility shows a strong correlation with S (r = 0.92), Co (r = 0.90), and Bi (r = 0.87); moderate correlation with Fe₂O₃, Al₂O₃, and As; and negative correlation with Mn, TiO₂, Zn, and Pb. The ferromagnetic phase most likely originates from pyrrhotite, as well as hematite formed during pyrite alteration and goethite. Full article

This research focuses on the investigation of microstructure, deformation, and superplastic behavior in wide range of strain rates of novel crossover Al-Zn-Mg-Cu alloy with Y/Er. The precipitation and superplastic behavior of the Al-Zn-Mg-Cu-Zr-Cr-Ti with Er/Y and Fe/Si impurities alloys have been studied. The microstructure of the alloys with nano-sized precipitates and micron-sized particles allows obtaining a micrograin stable microstructure. The spherical D0₂₃-Al₃(Er,Zr) precipitates with a diameter of about 20 nm and rod-like crystalline and qusicrystalline E (Al₁₈Mg₃Cr₂) precipitates with a thickness of about 20 nm and length of about 150–200 nm were identified by transmission electron microscopy. The superplastic deformation behaviors were investigated under different temperatures of 460–520 °C and different strain rates of 3 × 10⁻⁴ to 3 × 10⁻³ s⁻¹. The microstructure observation shows that uniform and equiaxed grains can be obtained by dynamic recrystallization before superplastic deformation. The alloy with Y exhibits inferior superplastic properties, while the alloy with Er has an elongation of more than 350% at a rate of 1 × 10⁻³ s⁻¹ and a temperature of 510 °C. Full article

Stroke remains a leading cause of death and disability worldwide, yet the contribution of elemental imbalance to its pathogenesis is not fully understood. Experimental evidence suggests that disturbances in the concentrations of essential and toxic elements contribute to neuronal injury through excitotoxicity, oxidative stress, and inflammation. In this study, we examined regional concentration in 15 elements (Na, K, Ca, Mg, P, Fe, Zn, Cu, Mn, Se, Cr, V, Pb, Al, B) in the subacute phase of ischemic stroke using the middle cerebral artery occlusion (MCAO) rat model. Male Sprague–Dawley rats underwent MCAO or sham surgery, after which the contralateral cortex, dorsal striatum, and hippocampus were collected seven days post-surgery. Elemental concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and analyzed by Student’s t-test, cluster analysis, and principal component analysis (PCA). The t-test revealed widespread changes in Ca, while Na was least affected. PCA identified three principal components that explained 81.63% of the variance, with Mn, Zn, Se, K, Mg, Fe, and P contributing most strongly. Cluster analysis distinguished MCAO from sham groups and revealed region-specific responses. Our findings demonstrate long-lasting, region-dependent elemental imbalance after stroke, suggesting a valuable role of elemental profiling. Future investigations should aim to identify elements whose concentrations exhibit alterations not only within central nervous system regions but also in peripheral compartments, such as blood serum, as these changes may hold significant diagnostic and prognostic value. Full article

Zinc oxide nanowires are often used to improve the bulletproof performance of high-performance fabrics, but determining the coefficients of inter-yarn friction (CIFs) of those fabrics in numerical ballistic models is a challenge. In this article, the linear method is adopted to obtain the CIF of sateen fabrics with two thread densities treated with zinc oxide nanowires. For treated sateen fabrics with a thread density of 8 ends/cm (S-8-ZnO), the coefficient of static friction (CSF) and coefficient of kinetic friction (CKF) obtained by the linear method are 1.85 and 1.83, respectively. For treated sateen fabrics with a thread density of 13 ends/cm (S-13-ZnO), the CSF and CKF obtained by the linear method are 0.76 and 0.74, respectively. The obtained coefficients are input into the yarn pull-out models of the above two types of sateen fabrics. It is found that for both S-8-ZnO and S-13-ZnO fabrics, the errors of the yarn pull-out force by the linear method are 0.43% and 6.56%, respectively. The method presented in this study provides a more feasible approach for determining the CIF of chemically treated fabrics in future FE simulations. Full article

Reservoirs are hotspots for the coupling of nutrients and heavy metals, and they substantially modify the compositions and spatiotemporal distributions of microorganisms in fluvial systems. However, relatively few studies have been performed that investigate the microbial mechanisms driving interactions among heavy metals and nutrients in reservoirs. The Goupitan Reservoir, a seasonal stratified reservoir located within the Wujiang River catchment, was chosen as the research subject. The temporal and spatial variations in heavy metals and nutrients, and the metagenomic composition of the reservoir water were analyzed in January, April, July, and October 2019. The results revealed that As, Ni, Co, and Mn were derived primarily from mine wastewater, whereas Zn, Pb, Cd, and Cr were related to domestic and agricultural wastewater discharge. The study area was dominated by Proteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidetes, with the proportion of dominant phyla reaching 90%. Decreases in the dissolved oxygen (DO) concentration and pH in the bottom water during July and October were conducive to increases in the abundance of the anaerobic bacterial groups Planctomycetes and Acidobacteria. The functional genes norBC and nosZ associated with denitrification (DNF), the key gene nrfAH involved in the dissimilatory nitrate reduction to ammonium (DNRA) process, the functional genes aprAB and dsrAB responsible for sulfate reduction/sulfide oxidation, as well as the thiosulfate oxidation complex enzyme system SOX, all exhibit high abundance in hypoxic water bodies and peak in the redoxcline, highlighting the significance of related nitrogen (N) and sulfur (S) metabolic processes. In addition, the concentrations of heavy metals significantly affected the spatial differentiation of the planktonic bacterial community structure, with Mn, Co, Fe, Ni, As, and Cu making relatively high individual contributions (p < 0.01). This study is important for elucidating the sources and microbiological mechanisms influencing heavy metals and nutrients in seasonally stratified subtropical reservoirs. Full article

Black crusts are degradation features found on stone buildings, offering valuable insights into local pollution sources. Their composition and structure reflect environmental conditions, making them important indicators for environmental and conservation studies. In this study, black crusts collected from funerary monuments in the Monumental Cemetery of Milan were comprehensively characterized using SEM-EDX, Raman spectroscopy, LIBS, and oxidative potential (OP) assays. SEM-EDX and Raman spectroscopy revealed extensive degradation of the substrate and the incorporation of pollutant-derived particles, with heavy metals such as Fe, Zn, and Pb detected in more than 90% of the samples. Correlation analysis proved effective in distinguishing major pollution sources, primarily vehicular and railway traffic, indicated by strong associations such as Zn–Mn (r = 0.896), Fe–Zn (r = 0.734), and Fe–Mn (r = 0.655), from minor sources linked to industrial emissions, reflected in correlations including Ti–Pb (r = 0.589), Pb–Cl (r = 0.702), and S–Pb (r = 0.661). Instead, LIBS analysis confirmed stratigraphic penetration of these elements beyond the surface layers, suggesting long-term accumulation. OP assays, applied here for the first time to black crusts, showed values between 0.5 and 3.0 pmol min⁻¹ µg⁻¹, indicating moderate oxidative reactivity linked to metal content. Overall, the findings contribute to a deeper understanding of pollution-driven stone decay and support the development of more effective diagnostic and conservation strategies. Full article

Electrolysis and biological processes, such as fermentation and microbial electrolysis cells, offer efficient hydrogen production alongside wastewater treatment. This study presents a novel microbial electrolyzer (ME) comprising a titanium dioxide (TiO₂) anode, a nickel–iron–carbon (NiFeC) cathode, and a cellulose nanocrystal proton exchange membrane (CNC-PEM) designed to generate hydrogen from palm oil mill effluent (POME). The system is powered by a 12 V electric double-layer organic supercapacitor (EDLOSC) integrated with a ZnO/PVA-based solar thin film. Power delivery to the TiO₂-NiFeC-PEM electrolyzer is optimized using an Adaptive Neuro-Fuzzy Inference System (ANFIS). Laboratory-scale pilot tests demonstrated effective degradation of POME’s organic content, achieving a hydrogen yield of approximately 60%. Additionally, the nano-structured ZnO/CuO–ZnO/PVA solar film facilitated stable power supply, enhancing in situ hydrogen production. These results highlight the potential of the EDLOSC-encased ZnO/PVA-powered electrolyzer as a sustainable solution for hydrogen generation and industrial wastewater treatment. Full article

Novel pure Zn and Zn-3Ag-xFe (x = 0, 1, 3, 5) (wt.%) nanocrystalline powders were synthesized for potential use as implants and stent materials by the mechanical alloying (MA) technique. The morphological and structural alterations of the powders milled for 5, 10, and 20 h were examined. SEM research revealed that during MA, the original elemental powder particles were subjected to a cold-welding process, subsequently fracturing in a brittle manner. The EDX spectra of the powders milled for 20 h indicated a uniform distribution of components. Laser diffraction particle size examination proved that the Zn-3Ag-1Fe alloy had the smallest particle size at 58.8 µm. XRD examination indicates the existence of AgZn₃ and Fe₃Zn₁₀ intermetallic phases. The crystallite size diminishes with prolonged milling time, decreasing from 130 nm to 30 nm. The porosity rose from 11.62% for pure Zn to 15.35% in the Zn-3Ag-5Fe alloy, suggesting that the incorporation of Ag and the higher Fe ratio diminished the compressibility of the milled powders, as evidenced by density tests. The Zn-3Ag-5Fe alloy exhibited the maximum corrosion current density of 164.65 µA/cm², attributed to the microgalvanic effect and reduced relative density induced by the Fe₃Zn₁₀ phase, which escalated with higher Fe doping. The hardness of the Zn-3Ag-5Fe alloy rose from 34.5 ± 2.8 HV to 132.2 ± 4.6 HV compared to the pure Zn sample, while the wear coefficient decreased from 0.029 ± 0.003 mm³/Nm to 0.005 ± 0.001 mm³/Nm, corresponding with the hardness test results. In contrast to S. aureus, which exhibited an 87.8% susceptibility to antibacterial activity from 3% silver and iron additions, E. coli demonstrated over 85% susceptibility to antibacterial activity from silver addition alone. The Zn-3Ag and Zn-3Ag-1Fe samples demonstrated high biocompatibility, attaining cell survival rates of 99.2% ± 3.01% and 99.2% ± 4.02% for the 12.5% extract, respectively. This study demonstrates that the newly developed Zn-Ag-xFe alloys have exceptional mechanical properties and excellent biocompatibility. Furthermore, the variable biodegradation rate dependent on alloy type presents an avenue for further research. Full article

Bee pollen is highly regarded for its nutritional and therapeutic properties, and Tunisia’s diverse ecosystems provide ideal conditions to produce high-quality bee pollen. The aim of this study was to characterize seven polyfloral bee pollen samples from major Tunisian regions, analysing their physicochemical and phytochemical parameters to evaluate compliance with national quality standards and their potential contribution to human nutrition. The nutritional and biochemical characterization of bee pollen samples was performed using standardized methods. Phenolic, flavonoid, and tannin contents were measured by colorimetric assays; carotenoids and chlorophylls spectrophotometrically; amino acids and sugars by HPLC; fatty acids by GC–MS; and minerals by atomic absorption spectroscopy. Amino acid levels were relatively constant between samples, but significant differences (p < 0.05) were noted, with concentrations ranging from 4.93 ± 0.15 mg·kg⁻¹ (K-O4) to 82.72 ± 2.36 mg·kg⁻¹ (O-O4). Tyrosine, aspartic acid, and glutamic acid were the dominant amino acids in both total and free forms, while threonine was identified as the relatively limiting amino acid. The proportion of total essential amino acids (TEAA) to total amino acids (TAA) met the nutritional recommendations set by the FAO. A total of 16 fatty acids were quantified in the seven BP samples, including nine saturated and six unsaturated fatty acids, with total content ranging from 0.26 g/100 g⁻¹ (T-03) to 37.06 g/100 g⁻¹ (G-03), which the primary fatty acids identified were α-linolenic acid, palmitic acid, and oleic acid. However, palmitoleic acid was detected in only two samples, in small amounts (0.34% and 0.46%). Essential minerals such as K, Ca, P, Mg, Zn, Fe, Mn, and Cu were present in significant amounts, playing a crucial role in both plant metabolism and human health Despite variations between samples, Tunisian bee pollen was overall evaluated as a valuable dietary supplement. Full article

Sulfonated poly(ether ether ketone) (SPEEK) is one of the most studied ionic polymers for polymer electrolyte membranes (PEMs) in fuel cells (PEMFCs). To improve its proton conductivity, novel SPEEK/praseodymium-doped zinc spinel ferrite composite membranes of 130–170 μm thickness were prepared via ultrasound-assisted dispersion of various proportions of synthesized doped ferrite nanoparticles into the polymer solution, followed by a simple solution-casting method. The morphology (as observed by SEM and confirmed by DMA) and the conducted physical and chemical tests typical for PEMs, such as water uptake (32–44% at 80 °C), ionic exchange capacity (1.67–1.80 mEq/g), chemical (around 1% loss in Fenton reagent after 24 h), thermal stability (up to 190 °C) and tensile strength (39–50 MPa), were proven to depend on the content of inorganic filler in the composite (up to 5%). The proton conductivity of composite membranes (0.21–2.82 × 10⁻² S/cm at 80 °C) was assessed by broadband dielectric spectroscopy. The membrane with a content of 0.25 wt.% ZnFe_1.96Pr_0.04O₄ showed the best proton conductivity (3.41 × 10⁻² S/cm at 60 °C), as compared to 1.60 × 10⁻² S/cm for Nafion117 measured under the same conditions, demonstrating its suitability as a PEM for fuel cell applications. Full article

The limited availability of high-quality ore deposits and the environmental hazards of metallurgical wastes highlight the importance of developing resource-efficient metal recovery technologies. Zinc kiln slag (ZKS), also known as Waelz slag, a by-product material enriched in non-ferrous metals, was processed through oxidative HCl leaching with H₂O₂ as an oxidant. Thermodynamic simulation and laboratory experiments were applied to determine optimal leaching conditions to dissolve copper, zinc, and iron. Optimal leaching efficiency was achieved with consumptions of 0.8 g HCl and 0.1 g H₂O₂ per gram of ZKS, a liquid-to-solid (L/S) ratio of 5 mL/g, a temperature of 70 °C, and a duration of 180 min, which resulted in recoveries of 96.3% Cu, 93.6% Fe, and 76.8% Zn. The solid residue with 43.5 wt.% C is promising for reuse as a reductant material in pyrometallurgical processes. Copper and arsenic were separated from the leachate via cementation with iron powder, achieving recovery rates of 98.9% and 91.2%, respectively. A subsequent two-step iron precipitation produced ferric hydroxide with 52.2 wt.% Fe and low levels of impurities. As a result, the developed novel hydrochloric acid oxidative leaching and metal precipitation route for ZKS recycling provides an efficient and sustainable alternative to conventional treatment methods. Full article

Coconut yield and quality are significantly affected by multiple female inflorescences (MFF), which disrupt flower differentiation balance. To elucidate the molecular mechanisms, we compared MFF with normal female inflorescences (NFF) using phenotypic, morphological, physiological, and multi-omics approaches. The results revealed that MFF exhibited altered flower structures. MFF showed elevated iron (Fe), nitrogen (N), sulfur (S), potassium (K), calcium (Ca), zinc (Zn), proline (Pro), catalase (CAT), malondialdehyde (MDA), abscisic acid (ABA), and jasmonic acid (JA), but reduced molybdenum (Mo), soluble sugar (SS), soluble protein (SP), superoxide dismutase (SOD), peroxidase (POD), indole acetic acid (IAA), zeatin riboside (ZR), and gibberellic acid (GA). We detected 445 differentially expressed genes (DEGs) mainly enriched in ABA, ETH, BR, and JA pathways in MFF compared to NFF. We identified 144 differentially accumulated metabolites (DAMs) primarily in lipids and lipid-like molecules, phenylpropanoids and polyketides, as well as organic acids and derivatives in the comparison of MFF and NFF. Integrated analysis linked these to key pathways, e.g., “carbon metabolism”, “carbon fixation in photosynthetic organisms”, “phenylalanine, tyrosine, and tryptophan biosynthesis”, “glyoxylate and dicarboxylate metabolism”, “glycolysis/gluconeogenesis”, “pentose and glucuronate interconversions”, “flavonoid biosynthesis”, “flavone and flavonol biosynthesis”, “pyruvate metabolism”, and “citrate cycle (TCA cycle)”. Based on our results. the bHLH137, BHLH062, MYB (CSA), ERF118, and MADS2 genes may drive MFF formation. This study provides a framework for understanding coconut flower differentiation and improving yield. Full article

Soil arsenic (As) contamination presents serious threats to ecosystems and human health, necessitating the development of accurate and efficient monitoring techniques. This study introduces a novel multi-source data fusion approach to enhance the hyperspectral inversion of soil arsenic concentrations by integrating dimensionality-reduced spectral data with soil components significantly correlated with arsenic (e.g., Cd, Cr, Cu, Ni, Pb, Zn, S, and total Fe₂O₃(T-Fe₂O₃)). Principal Component Analysis (PCA) was utilized to reduce the dimensionality of hyperspectral data, effectively addressing issues of collinearity and redundancy while preserving critical spectral information. The performances of three models, namely Partial Least Squares Regression (PLSR), Artificial Neural Networks (ANN), and Random Forest (RF), were assessed under four input variable combinations: (1) original spectral data, (2) original spectral data with soil components, (3) PCA dimensionality-reduced spectral data, and (4) PCA dimensionality-reduced spectral data combined with soil components. The results demonstrated that the RF model, when applied to the multi-source data of PCA-reduced spectra and soil components, achieved the highest inversion accuracy with an R² value of 0.86, significantly outperforming the PLSR model (R² = 0.75). This study underscores the effectiveness of enhancing model performance and highlights the superior capability of the RF model in handling complex, high-dimensional datasets. The findings of soil arsenic estimation provide theoretical foundation for optimizing hyperspectral remote sensing technology in monitoring soil heavy metal contamination and establishing a robust framework for future research and practical applications in environmental science. Full article

Olive pomace (OP), an olive mill byproduct, poses environmental risks if mismanaged due to its high phenolic content, acidic pH, organic load, and electrical conductivity. This study evaluated the impact of olive pomace filtrate (OPF) at varying doses (OP-5, OP-10, OP-15) on broad bean (Vicia faba L.) growth, secondary metabolites, and nutrient accumulation. The highest OPF dose (OP-15) exhibited a clear negative, dose-dependent phytotoxic effect, causing stem discoloration, reduced root growth, necrosis, and chlorosis, while untreated controls showed vigorous growth. This significantly (p < 0.05) reduced leaf development, average number of leaves, and total leaf area, even at the lowest concentration (5%). Consequently, OP-15 reduced dry and fresh biomass by over 50% and shoot/root lengths by up to 61.55% compared to the control. Liquid chromatography mass spectrometry (LC-MS/MS) analysis revealed a positive dose-dependent effect of OPF on beneficial phenol and flavonoid accumulation, with significantly higher amounts of ferulic, isoferulic, caffeic, chlorogenic, and 4-hydroxybenzoic acids, as well as luteolin-4′-rutinoside and 4,7-dihydroxyflavone. OP application significantly (p < 0.05) decreased relative water content and increased electrolyte leakage and malondialdehyde, indicating stress. Furthermore, OP decreased the uptake of K, P, Fe, S, Zn, and Cu. Therefore, the intrinsic phytotoxicity of OPF suggests that mitigation measures are essential before considering environmental application to prevent potential adverse effects on sensitive crops and the wider ecosystem. Full article

In the burgeoning floriculture sector of Indian agriculture, optimizing yields of loose flowers like Ixora is crucial. This study investigates the impact of micronutrient management on floral quality, physiological attributes, and postharvest shelf life using four Ixora varieties treated with FeSO₄, ZnSO₄, and boric acid. The Pink variety (V₂) excelled in flower bud length (5.15 cm), bud width (0.38 cm), and corolla tube length (3.73 cm), and also demonstrated the longest shelf life (5.20 days at room temperature, 6.21 days refrigerated). Foliar spray of NPK + FeSO₄ (0.5%) + ZnSO₄ (0.5%) + Boric acid (0.2%) on the Pink variety (V₂ × T₄) further maximized bud length (5.44 cm), bud width (0.44 cm), corolla tube length (3.95 cm), and shelf life (6.09 days room temperature, 7.13 days refrigerated). These improvements are linked to zinc’s role in photosynthesis, iron’s role in chlorophyll synthesis, and boron’s role in cell wall strength, enhancing flower quality and marketability. Full article