Search Results (877)

The use of seawater in mineral processing poses significant challenges for solid–liquid separation, including polymer chain contraction, accelerated coagulation, and brittle aggregate formation. This study evaluates the impact of fractional dosing of anionic polyacrylamide (PAM) on the formation, structure, and sedimentation performance of flocs in quartz-kaolinite suspensions prepared in seawater. Four dosing schemes (1, 2, 3, and 4 pulses) were analyzed, maintaining a total dose of 15 g/t and flocculation times of 75, 90, and 105 s. Sedimentation assays, kinetic monitoring using FBRM, size distributions, fractal dimensions, and bulk density were integrated to characterize the aggregation process. The results show that all fractional strategies outperform single-pulse dosing, with the three-pulse scheme (0–30–60 s) standing out, achieving the highest settling rates, the most significant fines reduction, and the best structural robustness. FBRM kinetics reveal stepped growth, less shear breakage, and more stable maturation when polymer addition is divided temporally. Consistently, fractal dimension and aggregate density reach their maximum values after three 90 s pulses, indicating more compact, less porous structures. Zeta potential analysis confirms a strong polymer-particle interaction in kaolinite under high salinity. The superior performance of the multi-pulse strategy is explained by the progressive availability of active polymer segments during aggregate formation and maturation. Each pulse is incorporated into a partially structured suspension, in which unoccupied mineral surfaces and flocs from the early stages of consolidation still exist. This staggered adsorption avoids local overdosing associated with flash injections, improves bridging efficiency, reduces brittle aggregate formation, and promotes more uniform restructuring. Full article

We demonstrate that pulsed laser annealing induces plasmonic gold nanoparticles in ZnO thin films, monitored in real-time via pulse-by-pulse spectroscopy. Initially embedded gold nanoparticles (smaller than 5 nm) in sputtered ZnO films were annealed using 532 nm pulses from a Q-switched Nd:YAG laser while monitoring transmission spectra in situ. A plasmonic resonance dip emerged after ~100 pulses in the 530–550 nm region, progressively deepening with continued exposure. Remarkably, different incident energies converged to a thermodynamically stable optical state centered near 555 nm, indicating robust nanoparticle configurations. After several hundred laser shots, the process stabilized, producing larger nanoparticles (40–200 nm diameter) with significant surface protrusion. SEM analysis confirmed substantial gold nanoparticle growth. Theoretical modeling supports these observations, correlating spectral evolution with particle size and embedding depth. The protruding gold nanoparticles can be functionalized to detect specific biomolecules, offering significant advantages for biosensing applications. This approach offers superior spatial selectivity and real-time process monitoring compared to conventional thermal annealing, with potential for optimizing uniform nanoparticle distributions with pronounced plasmonic resonances for biosensing applications. Full article

Nanoplastics pose significant environmental and public health risks, prompting the need for sensitive, cost-effective, and rapid assays for ecotoxicity assessment. The present work proposes the use of a portable smartphone-based platform to enhance traditional Daphnia magna acute toxicity assays by integrating behavior analysis and heart rate measurements. The aim is to improve sensitivity in detecting toxic effects of nanoplastics. In particular, the study focused on nano-sized carboxylated polystyrene (PS) nanoparticles. Two variability factors that could influence biological effects of nanoplastics, the particle size and the age of the organisms, were considered. Results demonstrated that the application of the proposed integrated approach allowed the detection of early subtle effects such as a significant impact on the heart rate and behavior of Daphnia magna under short-term exposure to PS carboxylated nanoparticles. In particular, a stimulation of heart rate was observed for both neonates and adults either for 40 nm or 200 nm particles after 48 h exposure, presumably attributable to an interference of carboxylated PS NPs with adrenergic-type receptors. Behavioral alterations were detectable for 40 nm particles but not for 200 nm ones consisting of a decrease in velocity and alterations of trajectories. Obtained results demonstrated the suitability of the proposed smartphone platform for friendly and real-time integration of behavioral analysis with physiological outcome measurements during acute exposure of Daphnia magna to nano-sized carboxylated PS NPs, expanding the sensitivity of the traditional acute toxicity tests. It offers a novel, cost-effective, and field-applicable method for environmental monitoring of nanoparticle toxicity and impact. Full article

This study investigates the impact of tire wear particles (TWPs) and their dissolved organic matter (DOM) on soil DOM dynamics and heavy metal behavior. Through short-term incubation experiments under simulated natural conditions with TWPs of varying particle sizes, we analyzed ecological changes in soil. Using three-dimensional excitation–emission matrix (3D-EEM) spectroscopy coupled with parallel factor analysis, we monitored the photochemical properties and compositional evolution of soil dissolved organic matter. Results demonstrate that TWP amendment substantially alters soil DOM molecular characteristics, inducing a sharp decrease in protein-, carbohydrate-, and lipid-like components, the degradation of low-aromaticity unstable dissolved organic matter, and an overall increase in aromaticity. Furthermore, TWP input directly modified soil properties, triggering the transformation of soil aggregates: the proportion of large aggregates significantly decreased while that of small aggregates increased, thereby reducing overall aggregate stability. The bioaccessibility of heavy metals (HMs) (Cd, Cu, and Zn) extracted by CaCl₂ increased, primarily due to the release of endogenous metals from TWPs, compounded by the disruption of soil aggregates. In contrast, Pb tended to transform into more stable fractions under TWP stress, reducing its bioaccessibility. Further correlation analysis indicated that TWPs indirectly affected HM (Cd, Cu, and Zn) fractionation by influencing the soil dissolved organic matter properties and soil properties. This study provides a new perspective for elucidating the interplay between dissolved organic matter and HMs in urban soils, as mediated by tire wear particles (TWPs). Full article

Planetary journal bearings are enablers for wind turbine gearbox torque density and reliability increase due to their compactness and potentially unlimited lifetime. They are designed to withstand the load conditions during wind turbine operation. Despite their general robustness, abnormal events such as particle contamination, strong overload or operation without sufficient oil supply may be harmful to the bearings. In these cases, damage can occur quickly and with little warning time. Such spontaneous failure leads to turbine downtime and cost-intensive repair work on the wind turbine drive train. Thus, reliable load and condition monitoring systems, which allow the detection of critical operating states before damage occurs, would be beneficial. For journal bearings in wind turbine gearboxes, no commercially available monitoring system exists to date. The existing studies on journal bearing condition monitoring are limited to experiments on component test rigs or small gearboxes, and their transferability to full-size systems has yet to be proven. This work presents the results of a system test with an 850 kW wind turbine gearbox equipped with planetary journal bearings and a novel condition monitoring system based on the measurement of surface acoustic waves. First, the journal bearing design, including the sensor setup, is explained. Second, the test campaign layout is presented. The gearbox is tested under load conditions specific to wind turbines, and the condition monitoring signals are examined in detail. An algorithm based on a machine learning model is presented for evaluating the monitoring signals and predicting the friction state of the bearings. Finally, the practical feasibility and quality of the monitoring approach for planetary journal bearings presented in this work is discussed. Full article

Microplastics are very small particles of plastics, usually smaller than 5 mm. Microplastic pollution has emerged as a rising and challenging issue worldwide, posing serious threats to aquatic and terrestrial ecosystems and human health. Because of global demand and frequent use in daily routines, including clothing, packaging, and household items, the production of plastic is increasing annually. This study provides a comprehensive overview of the source, classification (based on shape, color, polymer), transportation, and impact of microplastic pollution. Depending upon size, mass, and density, microplastics can be transported to the environment via air and water. However, microplastics can be inhaled and ingested by humans, causing various health issues; for example, aquatic organisms like small fish ingest microplastics, which accumulate through the food chain and end up in the human body. This can lead to physiological harm, including inflammation, digestion tract obstruction, biomagnification throughout the food chain, and reproductive failure. This study further highlighted initiatives taken by government agencies to address plastic and microplastic pollution across India; for example, The Ministry of Environment Forest and Climate Change (MoEFCC) has formulated and amended the Plastic Waste Management (PWM) rules, Mission LiFE (LiFEStyle for Environment) launched campaigns such as “Say No to Single Use Plastic” and “One Nation, One Mission: End Plastic Pollution” to create awareness at the grassroot level, and institutions like the Food Safety and Standards Authority of India (FSSAI) have initiated a project to detect microplastics in food products. In addition, the National Green Tribunal (NGT) has instructed the Central Pollution Control Board (CPCB) to actively take measures to address microplastic pollution across Indian cities, focusing on key parameters like air, water, food, and humans. This study presents several recommendations, including detection and removal techniques (conventional, advanced, and removal); strengthening legislative policies such as Extended Producer Responsibility (EPR); research collaboration and monitoring with institutions such as CSIR-IITR, ICAR-CIFT, and BITS-Pilani; integrating EPR and Material Recovery Facilities (MRF) to develop a circular economy model; and mass awareness through government initiatives like the Swachh Bharat and Smart City programs to foster long-term behavioral change. Full article

This study investigates the settlement characteristics of overlying strata in backfilled stopes at the Sanshandao Gold Mine, focusing on the compaction behavior of backfill materials. Integrating laboratory tests, numerical modeling, and field monitoring, we analyzed the particle size distribution and fractal dimensions of tailings (2.1525) and C material (2.1994), with tailings showing better gradation. Systematic compaction tests examined the effects of mix ratio, water content, and curing time. Results indicate that compression follows a viscous sliding model with exponential curves, progressing through three stages—pore compaction, structural deformation, and elastic/plastic deformation—with energy dissipation ratios of 1:5:18. Water content was the most influential factor, with optimal compaction occurring at 5~8%. Coupled Midas-Flac3D simulations estimated a theoretical compaction rate of 0~2% in filled stopes, excluding seepage and equipment effects. Field monitoring at the −480 m level revealed non-uniform settlement, with maximum subsidence of 63.75 mm above stopes and initial settlement rates of 12~20 mm/month. At the −520 m mining level, the backfill compaction rate reached 0.31%, with minor future increases expected. These findings offer valuable guidance for backfill mixture design and strata control in mining engineering. Full article

Airborne magnetic particles (AMPs) are associated with potentially toxic elements, and their size, mineralogy, and concentration can significantly impact both the environment and human health. However, their spatial analysis is often limited by small datasets, non-normality, and pronounced local variability. In this work, two sites with distinct demographic and geographic characteristics, the city of Mar del Plata (Argentina) and the Aburrá Valley region (Colombia), were analyzed using the fuzzy Magnetic Pollution Index (IMC) as an indicator of the concentration of AMPs. Moreover, an original methodological framework that explicitly incorporates measurement uncertainty through fuzzy numbers, combined with an approach modeling fuzzy semivariances via α-cuts, performs spatial prediction via ordinary kriging. This study produces maps that simultaneously reflect the magnitude of IMC and its associated uncertainty. Unlike classical geostatistics, the fuzzy-based model captures the inherent imprecision of magnetic measurements and reveals spatial patterns where uncertainty becomes informative about the type and origin of pollution. In particular, this approach demonstrates that areas with higher IMC levels are associated with high anthropic activity (near industrial zones, main avenues, slow traffic). In contrast, lower values were found in residential areas. Overall, the fuzzy-driven approach provides an additional layer of information not accessible through traditional methods, improving spatial interpretation and supporting the identification of priority areas for environmental monitoring. Full article

Fungal aerosols are critical yet understudied bioaerosol components in enclosed poultry environments, particularly during winter when ventilation is restricted. This study investigated stage-specific variations in fungal aerosol concentration, size distribution, and community composition in Taihang chicken houses across three growth stages (15, 60, and 150 days). Culturable fungal concentrations significantly increased from 3.16 × 10³ CFU/m³ to 1.24 × 10⁴ CFU/m³ with bird age (p < 0.001, ANOVA). Respirable particles (<4.7 μm) consistently dominated the fungal size distribution. ITS sequencing revealed progressive increases in fungal richness and distinct community shifts among stages. Several fungi with zoonotic potential, including Aspergillus, Cladosporium, Cryptococcus, and Fusarium, were detected across all stages. These findings demonstrate that wintertime enclosed ventilation, while thermally beneficial, promotes the accumulation of respirable fungal aerosols and elevates occupational and environmental health risks. From a One Health perspective, stage-specific mitigation strategies—such as ventilation optimization, reduction in organic dust sources, and routine monitoring of respirable fungal fractions—are essential for reducing exposure risks in cold-season poultry production. Full article

Background: Inactivated enterovirus 71 (EV71) vaccines play a vital role in preventing severe cases of hand, foot, and mouth disease, with their quality and stability determined by the degree of viral particle aggregation. Objective: This study aimed to use dynamic light scattering (DLS) for monitoring EV71 particle size, comprehensively evaluate the effects of environmental stresses on viral aggregation, and identify suitable stabilizing agents. Methods: The DLS technique was validated. Using this method, the effects of pH, ionic strength, freeze–thaw cycles, temperature, and mechanical stresses on viral particle size were assessed. Additionally, the ability of different buffer salts and stabilizers to inhibit stress-induced aggregation was systematically evaluated. Results: The DLS method exhibited robust performance. EV71 particles were stable at pH 7.0–7.5. Exposure to 47 °C and magnetic stirring promoted viral aggregation. Phosphate buffer and citrate buffer exhibited the highest inhibitory effects on heat-induced aggregation and stirring-induced aggregation, respectively. M199 and Tween 80 efficiently mitigated heat-induced particle aggregation and shear stress-induced particle aggregation, respectively. Conclusions: This study demonstrated the performance of DLS in viral aggregation monitoring. Additionally, this study revealed tailored stabilization strategies, providing key insights for vaccine formulation and quality control. Full article

Garden waste is a solid waste produced by plant littering or pruning. Improper disposal can easily pollute the environment. The addition of bulking agents (BAs) can improve the efficiency of organic waste composting. In this study, garden waste and dairy manure were used as raw materials, and easily available and recyclable branches were used as bulking agents to realize the synergistic resource utilization of the two. Three treatments were set up in the experiment, and 10% crushed branches, 1 cm branches, and 3 cm branches were added to the raw materials, respectively. The results showed that compared with the control group (adding crushed branches), the addition of 1 cm branches and 3 cm branches increased the cellulose degradation rate by 13.16–13.33% and the hemicellulose degradation rate by 18.24–23.86%. The monitoring results of CO₂ release showed that the cumulative CO₂ release of the treatment groups with 1 cm and 3 cm branches was 78.56 L and 102.17 L, respectively, which was significantly higher than that of the crushed branches (67.24 L), indicating that the addition of 1 cm and 3 cm branches increased microbial activity and degradation efficiency. Microbial diversity analysis further showed that in the treatment group with 1 cm branches, the number of nodes in the co-occurrence network increased by 24.11% and 2.84%, respectively, compared with the crushed branches and 3 cm branches, and the number of edges increased by 44.25% and 19.72%, forming the most abundant and complex microbial community, which verified its promotion effect on the composting process from the microbial level. In summary, this study recommends the use of branches with a particle size of 1 cm as BAs for garden waste composting. Full article

Cu₂ZnSnSe₄ is a promising light-absorbing material for cost-effective and eco-friendly thin-film solar cells; however, its synthesis often leads to secondary phases that limit device efficiency. To overcome these challenges, we devised a straightforward and efficient method to obtain single-phase Cu₂ZnSnSe₄ nanocrystalline powders directly from the elements Cu, Zn, Sn, and Se via mechanochemical synthesis followed by vacuum annealing at 450 °C. Phase evolution monitored by X-ray diffraction (XRD) and Raman spectroscopy at two-hour milling intervals confirmed the formation of phase-pure kesterite Cu₂ZnSnSe₄ and enabled tracking of transient secondary phases. Raman spectra revealed the characteristic A₁ vibrational modes of the kesterite structure, while XRD peaks and Rietveld refinement (χ² ~ 1) validated single-phase formation with crystallite sizes of 10–15 nm and dislocation densities of 3.00–3.20 10¹⁵ lines/m². Optical analysis showed a direct bandgap of ~1.1 eV, and estimated linear and nonlinear optical constants validate its potential for photovoltaic applications. Scanning electron microscopy (SEM) analysis showed uniformly distributed particles 50–60 nm, and energy dispersive X-ray (EDS) analysis confirmed a near-stoichiometric Cu:Zn:Sn:Se ratio of 2:1:1:4. X-ray photoelectron spectroscopy (XPS) identified the expected oxidation states (Cu⁺, Zn²⁺, Sn⁴⁺, and Se²⁻). Electrical characterization revealed p-type conductivity with a mobility (μ) of 2.09 cm²/Vs, sheet resistance (ρ) of 4.87 Ω cm, and carrier concentrations of 1.23 × 10¹⁹ cm⁻³. Galvanostatic charge–discharge testing (GCD) demonstrated an energy density of 2.872 Wh/kg⁻¹ and a power density of 1083 W kg⁻¹, highlighting the material’s additional potential for energy storage applications. Full article

Bangladesh generates approximately 3000 tons of plastic waste daily, and high mismanagement leads to substantial discharge into soils, rivers, and oceans. Limited research exists on plastic pollution along Cox’s Bazar in southeastern Bangladesh, with no studies spanning the entire coast; this study provides the first comprehensive assessment of the full coastline. This study investigates the abundance, types, and distribution of macro-, meso-, and microplastics in sediments from 23 stations covering Tourism, Active, and Less Active areas. Plastics were classified by size, shape, color, and polymer composition using stereomicroscopy and Fourier Transform Infrared Spectroscopy (FTIR), while spatial patterns of microplastic polymers were analyzed using Inverse Distance Weighted (IDW) interpolation. A total of 11,558 plastic particles were identified, with microplastics dominating (409.04 particles/m²), followed by mesoplastics (60.7 particles/m²) and macroplastics (32.8 particles/m²). Expanded polystyrene (EPS) and fragments were the most prevalent shapes, while transparent-white particles dominated in color. Polystyrene (PS), polypropylene (PP), and polyethylene (PE) comprised over 95% of polymers. IDW mapping highlighted Tourism, urban, and industrial zones as microplastic hotspots, with higher abundances in tourism areas. These findings provide a baseline for monitoring coastal plastic pollution and emphasize improved plastic management and recycling, contributing globally to understanding contamination in rapidly urbanizing, tourism-driven developing regions. Full article

Composite structures are generally more susceptible to impact damage than non-composite structures, and early identification of damage is the primary goal of structural health monitoring (SHM). If such damage remains undetected or reaches a critical size, it can lead to sudden collapse and catastrophic failure. Modern SHM methods aim to preserve the integrity of composite structures through continuous inspection, monitoring, and damage assessment, including detection, localization, quantification, classification, and prognosis. These methods use sensor-based technologies to assess vibration, extension, and acoustic and thermal emission. This paper provides a review of various computational methods including physics-based methods (signal processing techniques, modal analysis, and finite element model updating) and optimization methods (inverse problems, particle swarm optimization, topology optimization, genetic algorithms, time series analysis, and hybrid techniques), alongside machine learning methodologies employing neural networks as well as deep learning for damage identification in composite structures. These computational and learning-based techniques are widely applied in the development of algorithms, optimization strategies, and hybrid frameworks for SHM. The review further summarizes the applications, advantages, and limitations of each method according to structure type and damage characteristics. The key emphasis of this review is on integrating computational approaches, as well as machine learning, to enhance the efficiency of damage identification. The conclusion is drawn based on an overview of the literature, focusing on the contributions of different computational methods and machine learning for damage identification in composites. Full article

The mechanized processing of waste agricultural film is a crucial technical pathway for addressing agricultural-film pollution. Achieving resource recovery through mechanized waste-film processing—and thereby promoting the sustainable management of agricultural-film pollution—remains a major challenge for green agricultural development. This study systematically reviews the progress and limitations of shredding and film–impurity separation technologies deployed in China’s mechanized waste-film treatment. Based on multi-database searches and citation tracking of the literature published between 2000 and 2025, it comparatively evaluates key unit operations, including cutterhead/blade kinematics, specific energy-consumption (SEC) control, and airflow (air-classification) separation, complemented by engineering analyses of representative machinery. The findings indicate that integrated mechanized recovery lines have become the mainstream approach, although the recovered fraction still contains a high impurity load. Drum-type and shear-type shredding exhibit trade-offs between energy efficiency and mitigation of film wrapping/entanglement. Airflow separation and drum-screen or vibrating-screen modules show reduced separation efficiency and process stability at high moisture contents or when impurities have particle sizes comparable to the film; system complexity and maintenance burdens also warrant consideration. To address these issues, a process framework is proposed that integrates drum pre-crushing, shear fine shredding, air classification, and multi-stage screening, together with variable-frequency drive (VFD) speed control, torque monitoring, and modular design, providing a sustainable pathway for the clean separation and resource recovery of agricultural plastic film waste. Full article