Search Results (338)

Background/Objectives: Airborne viral diseases pose a health risk, due to which there is a growing interest in developing filter materials capable of capturing fine particles containing virions from the air and that also have a virucidal effect. Nanofiber membranes made of poly(vinylidene fluoride) dissolved in N,N-dimethylacetamide and functionalized with copper, silver, and zinc nanoclusters were fabricated via electrospinning. This study aims to evaluate and compare the virucidal effects of nanofibers functionalized with metal nanoclusters against the human influenza A virus A/WSN/1933 (H1N1) and SARS-CoV-2. Methods: A comprehensive characterization of materials, including X-ray diffraction, scanning electron microscopy, microwave plasma atomic emission spectroscopy, thermogravimetric analysis, contact angle measurements, nitrogen sorption analysis, mercury intrusion porosimetry, filtration efficiency, and virucidal tests, was used to understand the interdependence of the materials’ physical characteristics and biological effects, as well as to determine their suitability for application as antiviral materials in air filtration systems. Results: All the filter materials tested demonstrated very high particle filtration efficiency (≥98.0%). The material embedded with copper nanoclusters showed strong virucidal efficacy against the SARS-CoV-2 alpha variant, achieving an approximately 1000-fold reduction in infectious virions within 12 h. The fibrous nanowire polymer functionalized with zinc nanoclusters was the most effective material against the human influenza A virus strain A/WSN/1933 (H1N1). Conclusions: The materials with Cu nanoclusters can be used with high efficiency to passivate and kill the SARS-CoV-2 alpha variant virions, and Zn nanoclusters modified activated porous membranes for killing human influenza A virus A7WSN/1933 (H1N1) virions. Full article

In this paper, a discrete element method (DEM) coupled with a finite element method (FEM) was used to elucidate the impact of packing structures and size ratios on the cold die compaction behavior of pure copper powders. HCP structure, SC structure, and three random packing structures with different particle size ratios (1:2, 1:3, and 1:4) were generated by the DEM, and then simulated by the FEM to analyze the average relative density, von Mises stress, and force chain structures of the compact. The results show that for HCP and SC structures with a regular stacking structure, the average relative densities of the compact were higher than those of random packing structures, which were 0.9823, 0.9693, 0.9456, 0.9502, and 0.9507, respectively. Compared with their initial packing density, it could be improved by up to 21.13%. For the bigger particle in HCP and SC structures, the stress concentration was located between the adjacent layers, while in the small particles, it was located between contacted particles. During the initial compaction phase, smaller particles tend to occupy the voids between larger particles. As the pressure increases, larger particles deform plastically in a notable way to create a stabilizing force chain. This action reduces the axial stress gradient and improves radial symmetry. The transition from a contact-dominated to a body-stress-dominated state is further demonstrated by stress distribution maps and contact force vector analysis, highlighting the interaction between particle rearrangement and plasticity. Full article

Electroless silver (Ag) plating has emerged as a simple yet effective surface modification technique, garnering significant attention in consumer electronics and composite materials. This study systematically investigates the influence of glucose dosage on the microstructural refinement of Ag coatings deposited from silver–ammonia solutions onto iron (Fe) particles while also evaluating the oxidation resistance of Ag-plated particles through thermogravimetric analysis. Optimal results were achieved at a silver nitrate concentration of 0.02 mol/L and a glucose concentration of 0.05 mol/L, producing Fe particles with a uniform and dense silver coating featuring an average Ag grain size of 76 nm. The moderate excess glucose played a dual role: facilitating Ag⁺ ion reduction while simultaneously inhibiting the growth of Ag atomic clusters, thereby ensuring microstructural refinement of the silver layer. Notably, the Ag-plated particles demonstrated superior oxidation resistance compared to their uncoated counterparts. These findings highlight the significance of fine-grained electroless Ag plating in developing high-temperature conductive metal particles and optimizing interfacial structures in composite materials. Full article

The present study focuses on the dynamics of trace metals (TM) in two European rivers, the Mosel and the Meuse. A deterministic description of hydro-sedimentary processes has been performed. The model used to describe pollutant transport and dilution at the watershed scale has been enhanced with the implementation of the MicMod sub-model. The objective of this study is to characterise the dynamics of TM in the water column and bed sediment. A multi-class grain size representation has been developed in MicMod. The dissolved and particulate TM phases have been calculated with specific partitioning coefficients associated with each suspended sediment (SS) class. The processes involved in TM fate have been calibrated in MicMod, including settling velocity, TM releases from the watershed (point and diffuse loads), etc. Following the calibration of the parameters involved in TM transport within the river ecosystem, the main goal is to describe TM dynamics using a pressure–impact relationship model. It was demonstrated that the description of at least one class of fine particles is necessary to obtain an adequate representation of TM concentrations. The focus of this study is low flow periods, which are characterised by the presence of fine particles. The objective is to gain a deeper understanding of the processes that control the transport of TM. This paper establishes consistent pressure–impact relationships between TM loads (urban, industrial, soils) from watersheds and concentrations in rivers. Full article

The rapid rise of flexible AMOLED displays has prompted manufacturers to advance technologies to meet growing global demand. However, high costs and quality inconsistencies hinder industry competitiveness and sustainability. This study addresses these challenges by developing an intelligent optimization system for the fine metal mask (FMM) etching process, a critical step in producing high-resolution AMOLED panels. The system integrates advanced optimization techniques, including the Taguchi method, analysis of variance (ANOVA), back-propagation neural network (BPNN), and a hybrid particle swarm optimization–genetic algorithm (PSO-GA) approach to identify optimal process parameters. Experimental results demonstrate a marked improvement in product yield and process stability while reducing manufacturing costs. By ensuring consistent quality and efficiency, this system overcomes limitations of traditional process control; strengthens the AMOLED industry’s global competitiveness; and provides a scalable, sustainable solution for smart manufacturing in next-generation display technologies. Full article

Nanostructured bimetallic IrSn composites deposited on the natural aluminosilicate montmorillonite were synthesized and evaluated as anode electrocatalysts for polymer electrolyte membrane electrolysis cells (PEMECs). The test series prepared via the sol–gel method consisted of samples with 30 wt. % total metal content and varying Ir:Sn ratio. The performed X-ray diffraction analysis and high-resolution transmission electron icroscopy registered very fine nanostructure of the composites with metal particles size of 2–3 nm homogeneously dispersed on the support surface and also intercalated in the basal space of its layered structure. The electrochemical behavior was investigated by cyclic voltammetry and steady-state polarization techniques. The initial screening was performed in 0.5 M H₂SO₄. Then, the catalysts were integrated as anodes in membrane electrode assemblies (MEAs) and tested in a custom-made PEMEC. The electrochemical tests revealed that the catalysts with Ir:Sn ratio 15:15 and 18:12 wt. % demonstrated high efficiency toward the oxygen evolution reaction during repetitive potential cycling and sustainable performance with current density in the range 140–120 mA cm⁻² at 1.6 V vs. RHE during long-term stability tests. The results obtained give credence to the studied IrSn/MMT nanocomposites to be considered promising, cost-efficient catalysts for the oxygen evolution reaction (OER). Full article

Fine particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM_2.5) has been extensively studied due to its adverse health effects. Most research has focused on its impact on the respiratory system; however, increasing attention is being directed toward its effects on the brain. Associations between air pollution and neurological disorders—such as Alzheimer’s disease, cerebral infarction, and autism spectrum disorder—have been reported, with mechanism-based studies in animal models providing further insights. PM_2.5 comprises a complex mixture of thousands of chemical constituents. To elucidate its neurotoxicity mechanisms, it is essential to investigate both its transport pathways to the brain and the specific actions of its individual components. This review highlights key PM_2.5 components—water-soluble ions, metals, carbonaceous particles, polycyclic aromatic hydrocarbons, quinones, plastics, and bioaerosols—and outlines their potential routes of entry into the central nervous system, along with their associated mechanisms of action. By integrating these findings, this review contributes to a deeper understanding of the neurological effects mediated by PM_2.5, which represent one of the most critical aspects of its health impact. Full article

Tantalum carbide (TaC) is a highly refractory material with a melting point of 4153 K, making it attractive for applications requiring excellent hardness and thermal stability. In this study, we investigated the carburization behavior of high-purity tantalum metal powder synthesized by magnesium thermal reduction of Ta₂O₅, using activated carbon and graphite as carbon sources under high vacuum. Carburization was conducted at 1100–1400 °C for durations of 5–20 h. Carbon contents were analyzed via combustion analysis, and activation energies were calculated based on Arrhenius plots. The results showed that the activated carbon significantly enhanced carbon uptake compared to graphite due to its higher porosity and surface reactivity. The formation and transformation of carbide phases were confirmed via X-ray diffraction, revealing a progression from Ta to Ta₂C and eventually to single-phase TaC with increasing carbon content. Scanning electron microscopy (SEM) analysis showed that fine particles formed on the surface as carbon content increased, indicating local nucleation of TaC. Although the theoretical carbon content of stoichiometric TaC (6.22 wt.%) was not fully achieved, the near-theoretical lattice parameter (4.4547 Å) was approached. These findings suggest that activated carbon can serve as an effective carburizing agent for the synthesis of TaC under vacuum conditions. Full article

Particulate matter (PM) has been associated with various health issues. However, the most hazardous constituents of fine particles remain unclear, particularly in Asia where the chemical compositions are highly diverse and understudied. This study investigated the concentration and health risks of particulate-bound polycyclic aromatic hydrocarbons (PAHs) and heavy metals in the indoor air of religious spaces in Bangkok, Thailand. Air samples were collected from four religious sites during periods of high activity using a six-stage NanoSampler to capture particle sizes ranging from <0.1 to >10 µm. Chemical analyses were conducted using gas chromatography-mass spectrometry (GC-MS/MS) for PAHs and inductively coupled plasma-mass spectrometry (ICP-MS) for heavy metals. The results revealed significantly elevated concentrations of PM2.5, PAHs (notably benzo[a]anthracene (BaA), chrysene (CHR), and fluoranthene (FLU)), and heavy metals (particularly Mn, Ni, and Cu). Health risk assessments indicated that both the incremental lifetime cancer risk (ILCR) and hazard quotient (HQ) values for several pollutants exceeded the U.S. EPA safety thresholds, suggesting serious cancer and non-cancer health risks for workers exposed to these environments over prolonged periods. This study highlights incense burning as a dominant source of toxic indoor air pollutants and underscores the urgent need for mitigation strategies to reduce occupational exposure in religious buildings. Full article

This study investigates the concentrations, health risks, and potential sources of heavy metal elements and polycyclic aromatic hydrocarbons (PAHs) in PM_1.1 particles in Zhuji, a major copper-processing city in China. The ratios of heavy metals (summer: 0.906; winter: 0.619) and PAHs (>0.750 in both seasons) in PM_1.1/PM_2.0 suggest significant accumulation in ultrafine particles. In winter, heavy metal concentrations in PM_1.1 reached up to 448 ng/m³, and PAH concentrations were 13.4 ng/m³—over ten times higher than in summer. Health risk assessments revealed that hazard index (HI) values exceeded 1.00 for five age groups (excluding infants) during winter, indicating chronic exposure risks. Incremental lifetime cancer risk (ILCR) values surpassed the upper acceptable limit (1.0 × 10⁻⁴) for four age groups, with Cr, As, Cd, and Pb as major contributors. PAH-related ILCRs were also elevated in winter, with benzo[a]pyrene (BaP) identified as the most potent carcinogen. Enrichment factor (EF) and principal component analysis (PCA) indicated that industrial activities and traffic emissions were the dominant anthropogenic sources of heavy metals. Diagnostic ratio analysis further showed that PAHs mainly originated from vehicle and coal combustion. These findings provide critical insights into pollution patterns in industrial cities and underscore the importance of targeted mitigation strategies. Full article

Tin is a crucial strategic metal, extensively employed in aerospace, new energy materials, and other advanced fields. However, with the progressive depletion of high-grade tin ores, the utilization of low-grade tin ores for metal tin production has emerged as a significant trend. Nonetheless, low-grade tin ores present inherent challenges that hinder their direct application in tin extraction. Flotation remains an effective method to enhance ore grade, yet issues such as fine particle dispersion and ore complexity persist. In light of this, the present study provides a comprehensive review of cassiterite resource characteristics, surface chemistry, flotation reagents, and relevant case studies. By delving into the physicochemical properties of cassiterite, this paper elucidates its floatability and the distinctions among various flotation reagents. Furthermore, it identifies critical challenges in cassiterite flotation and proposes targeted, feasible strategies to support the efficient exploitation of tin resources, thereby fostering the sustainable development of the tin industry. Full article

The geopolitical and economic situation impacts raw materials demand. As principal ore deposits reach exhaustion, the study of new sources of raw materials becomes essential. Therefore, mining wastes emerge as alternative sources of raw materials. Their physicochemical properties, such as small particle size or concentration of some metals of interest, enhance reprocessing. A number of critical raw materials (As, Co, Cu, Sb) and base metals (Pb, Zn), as well as precious metals (Ag), were found present in an abandoned tailing deposit composed by finely grounded washed roasted pyrites within the Iberian Pyrite Belt. Copper leaching from a sample of this deposit was investigated. Two hydrometallurgical approaches were studied: acidic leaching with and without activated carbon; and alkaline leaching with glycine solutions. Leaching tests were carried out during 24 h at ambient and moderate temperatures (60 °C). In acidic medium, the maximum copper extraction varied from 88 to 92.5%, while in alkaline medium, the maximum copper extraction was in the range of 71%–76%. Using activated carbon and H₂O₂ seemed to slightly promote the copper extraction with the maximum extraction (92.5%) after 2 h of leaching at 60 °C. Complementarily, above 50% of the zinc and cobalt contained were extracted. In contrast, temperature in alkaline conditions played a key role in reaction speed, but also in precipitation of copper insoluble compounds. In addition, the glycine solution at pH 10–10.5 showed high selectivity for copper over zinc, iron, lead, arsenic, and antimony. Two extra tests at pH above 12 showed arsenic dissolution (up to 51% at pH 12.5). Full article

The CO₂ (Dry) Reforming of Methane (DRM) is a key process for reducing CO₂ and CH₄ emissions while producing syngas with an H₂/CO ratio of 1, ideal for Fischer–Tropsch synthesis. This study explores DRM and the Reverse Water Gas Shift (RWGS) reaction under mild conditions using Ru-based catalysts supported on CeO₂, YSZ, TiO₂, and SiO₂, with three reactant ratios: (i) stoichiometric, PCO₂ = 1 kPa, PCH₄ = 1 kPa, (ii) oxidizing, PCO₂ = 2 kPa, PCH₄ = 1 kPa, and (iii) reducing, PCO₂ = 1 kPa, PCH₄ = 4 kPa. The results highlight the importance of redox support for catalyst stability, with mobile lattice oxygen aiding carbon gasification. While Ru/CeO₂ is stable at high temperatures, it rapidly deactivates at low temperatures, emphasizing the need for precise metal particle size control. This work demonstrates the necessity of fine-tuning catalyst properties for more sustainable DRM, offering insights for next-generation CO₂ utilization catalysts. Full article

Printed circuit boards (PCBs) are fundamental components of electronic devices, acting as an important source of various valuable metals such as copper, gold, and silver. Efficient recycling methods that offer high recovery rates are essential to the full reutilization of these materials. Hydrometallurgical leaching is a prominent technique for metal recovery, but its efficiency can be significantly enhanced through solvent pre-treatment. In this study, an experimental analysis of the material composition of different categories of PCBs is presented. In addition, the study evaluates the influence of particle size on the subsequent copper leaching process and the efficiency of copper recovery. These investigations aim to better understand the material composition of PCBs and propose an optimized material recovery technique. The study finds that there are significant variances among the different categories of PCBs investigated, allowing a more informed handling process of WEEE. This research suggests that solvent pretreatment using DMSO for PCB particle sizes between 5.6 mm and 2 mm would be a good optimization technique, mitigating the drawbacks of treating fine particles while maintaining appealing recovery efficiency. Full article

In recent years, the field of bionic engineering has advanced at a remarkable pace. Numerous engineering challenges have been addressed through inspiration drawn from biological organisms in nature. In this paper, laser cladding was employed to fabricate a bionic unit inspired by the radial ribs of the bivalve shell surface morphology on 20CrMnTi steel, with the aim of enhancing its wear performance. The metallic powder used in the experiments was prepared by blending Ni60 alloy powder with tungsten carbide (WC) in a predetermined ratio. The WC content was maintained within a mass percentage range of 15% to 60% in the composite powder system. The microstructure and properties of the bionic unit were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and a hardness tester, while its dry sliding wear resistance was evaluated using a block-on-ring tribometer. The influence of the WC content on the microstructure, hardness, surface roughness, and wear performance of the bionic unit was investigated. The experimental results revealed that the bionic unit exhibited a dual microstructure comprising equiaxed crystals and fine dendritic structures. The incorporation of WC induced pronounced grain refinement, while the dispersed WC particles formed effective metallurgical bonding with the Ni-substrate. A positive correlation was observed between the WC content and hardness, with peak hardness reaching 1008 HV_0.2 at 60% WC. Tribological analysis demonstrated a wear mechanism transition from dominant abrasive wear to a hybrid abrasive–adhesive wear. The wear volume of the bionic unit decreased with increasing WC content, and the extent of damage was reduced. Full article