Search Results (4,241)

Floating plastic pellets spread rapidly after marine spills, reducing the efficiency of surface recovery. This study models floating pellet transport using advection, turbulent diffusion, Stokes drift, and particle loss, and quantifies patch expansion during the first $72\mathrm{h}$. Preliminary experiments with popcorn and styrofoam particles showed no lifting from the water surface under the tested conditions, indicating that wind moves light particles along the surface rather than into the air. A two-dimensional diffusion calculation was initialized with a $5650{\mathrm{m}}^2$ patch associated with a $28{\mathrm{m}}^3$ spill. Under constant diffusivity, the lower and upper cases reached $2.50$ and $6.00{\mathrm{km}}^2$ after $24\mathrm{h}$, followed by projected areas of $4.99$ and $11.99{\mathrm{km}}^2$ after $48\mathrm{h}$. Across diffusion coefficients of $0.5$–$2.0{\mathrm{m}}^2/\mathrm{s}$, the calculated $48\mathrm{h}$ area ranged from $3.26$ to $13.02{\mathrm{km}}^2$. These estimates describe how the patch may expand under the selected diffusion conditions and show that the area requiring surveillance and recovery may increase sharply within two days. The Python code used to generate the numerical results is provided to support reproducibility. Full article

To investigate how the position and thickness of ultrathin Al interfacial layers regulate the optoelectronic properties and temporal stability of AZO/Cu/AZO multilayer films, AZO/Cu/AZO (ACA), AZO/Al/Cu/AZO (AACA), and AZO/Al/Cu/Al/AZO (AACAA) multilayers were deposited on glass substrates by magnetron sputtering. For clarity, the stack notation is given from the film surface toward the substrate. AACA contains a 1 nm Al interfacial layer above Cu, whereas AACAA-1 and AACAA-2 contain Al layers on both sides of Cu with top/bottom thicknesses of 1/1 and 2/1 nm, respectively. The effects of Al layer insertion position and thickness on the microstructure, optoelectronic properties, and temporal stability were systematically investigated. The ACA and AACA films exhibited ZnO and Cu phases with preferred ZnO (002) and Cu (111) diffraction, respectively. The AACA film showed the best initial optoelectronic performance, with the average transmittance increasing from 75.9% to 85.7% and the sheet resistance decreasing from 18.5 to 6.7 Ω/sq, yielding a figure of merit (F_OM) of 3.2 × 10⁻² Ω⁻¹. After the additional Al layer was introduced beneath Cu, the Cu (111) signal became very weak and the sheet resistance increased markedly, indicating a substantial change in the structural and interfacial state of the ultrathin Cu layer. After two years of air exposure, pronounced Cu-O-rich particles were observed on the ACA surface, and the relative changes in average transmittance and sheet resistance reached 10.7% and 95.7%, respectively. In contrast, the corresponding changes for AACAA-2 were only 1.2% and 2.7%, demonstrating the best temporal stability. These results reveal a clear trade-off between initial optoelectronic performance and long-term stability and show that dual Al interfacial modification is an effective route for stabilizing AZO/Cu/AZO multilayer electrodes. Full article

Airborne microplastics (AMPs) are increasingly recognized as an emerging air pollutant. However, observational data remain scarce in Southeast Asia. This study provides the first observations of AMPs in Phnom Penh, Cambodia, using µFTIR-ATR imaging. Number concentration, morphology, polymer composition, aerodynamic size distribution, Feret diameter, and surface aging characteristics were investigated together with meteorological parameters, gaseous pollutants, water-soluble ionic tracers, and HYSPLIT backward trajectories to examine possible source attribution. AMPs were dominated by polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), with 52% classified as fragments and 82% having Feret diameter smaller than 30 µm. Across four independent 72-h sampling periods (n = 4), AMP concentrations ranged from 0.55 to 1.27 MP m⁻³ in TSP, with a mean ± standard deviation of 0.97 ± 0.30 MP m⁻³, and from 0.23 to 0.49 MP m⁻³ in the PM_2.5 fraction, with a mean ± standard deviation of 0.33 ± 0.10 MP m⁻³. In total, 134 particles were identified in TSP, of which 46 were detected in the PM_2.5 fraction. Carbonyl and hydroxyl indices indicated that PE and PP were relatively fresh and in low-to-moderate surface aging states. Pearson correlations suggested that the abundances of individual polymers were varied differently in relation to local environmental and precipitation-related variables; however, the limited number of sampling periods precludes source or process attribution. In addition, HYSPLIT backward trajectories showed that some air masses arriving in Phnom Penh had passed over marine regions under southwest monsoon flow. These findings provide the first baseline dataset for AMP pollution in Phnom Penh, Cambodia, and highlight the combined importance of local emissions and regional atmospheric transport in Southeast Asia. Full article

Providing a healthy environment in schools, particularly during a global pandemic, is crucial to saving occupants’ lives and reducing infection rates. This paper proposes a novel desk local exhaust ventilation (DLEV) system that uses a local exhaust diffuser integrated into a classroom desk. The performance of the system in providing a healthy and comfortable indoor thermal environment and reducing the risk of COVID-19 infection was assessed numerically. The assessment combined indoor thermal comfort indices and the bioaerosol dispersion behavior of airborne particles. The study was completed in a typical classroom layout, in which the results show that the DLEV system meets thermal comfort requirements by maintaining the gradients of vertical temperature within an acceptable range. The DLEV system increases the air motion in the breathing zone while keeping it within the recommended range of <0.25 m/s. The PMV and PPD indices are within recommended comfort levels for all but three occupants. Most notably, the DLEV system substantially reduces the concentration of bioaerosols, especially around the occupants’ head. This system works by capturing and removing the virus-rich aerosols exhaled by infected subjects before they disperse in the classroom. This lowers the risk of infection among healthy subjects. These findings confirm the effectiveness of the DLEV system in enhancing both thermal comfort and indoor air quality, making it suitable for environments where specific goals regarding occupants’ health and thermal management are required, such as in a classroom of healthy and infected subjects. Full article

Selective laser melting (SLM) and electron beam melting (EBM) enable the fabrication of commercially pure titanium, but the effects of the fabrication method and build orientation on surface characteristics and bonding remain unclear. This study evaluated the surface roughness, wettability, and shear bond strength of titanium fabricated by SLM and EBM at build orientations of 0°, 45°, and 90°, with titanium ingots intended for dental casting serving as reference specimens. The surfaces were wet-ground, air-abraded with 50 µm alumina particles, and treated with a 10-methacryloyloxydecyl dihydrogen phosphate-containing metal primer. Surface roughness (Sa), static water contact angles before and after primer application, and shear bond strength to a resin luting agent after 24 h of water storage were evaluated (n = 15/group). The EBM specimens fabricated at 90° exhibited significantly greater Sa values than the other groups (p < 0.05). Primer application significantly increased the water contact angle in all groups (p < 0.05), although group-dependent differences were observed. No significant differences in shear bond strength were detected among the fabrication conditions (p > 0.05). Thus, under the tested surface treatment conditions, differences in surface roughness and wettability were not accompanied by corresponding differences in the initial bond strength of commercially pure titanium. Full article

Atmospheric microplastics are increasingly recognized as mobile particulate contaminants that can be emitted, resuspended, transported, and deposited across indoor, terrestrial, marine, high-altitude, and remote environments. However, reported abundances and particle characteristics remain difficult to compare because studies differ in sampling design, reporting units, particle-size limits, contamination control, and polymer identification. This review combines concise bibliometric mapping with a critical narrative synthesis. A Web of Science Core Collection search for 2000–2024 retrieved 356 English-language articles and reviews, of which 280 met the eligibility criteria. Publication output increased rapidly after 2020. Co-citation and keyword analyses identified three major themes: occurrence, transport, and deposition; sampling and analytical characterization; and exposure and potential ecological and health implications. The synthesis shows that active air sampling and passive deposition collection measure different atmospheric processes, while inconsistent blank correction, recovery assessment, and polymer confirmation limit inter-study comparability. Field observations and modelling support long-range transport and the importance of particle morphology, but quantitative source attribution remains uncertain. Current evidence supports inhalation exposure and biological plausibility, yet is insufficient to establish population-level risks or causal links with specific diseases. Future research should prioritize harmonized monitoring, stronger QA/QC, improved detection of small particles and nanoplastics, and integrated transport–exposure assessment. Full article

Airborne microplastics and nanoplastics (MNPs) are increasingly reported in indoor, outdoor, and occupational air, but their aerobiological significance remains incompletely defined. This narrative review proposes the aeroplastic exposome as a cautious, testable framework for evaluating airborne MNPs as interfaces among aerosol transport, biological and chemical loading, aeroallergen co-exposure, inhalation, respiratory deposition, clearance, and airway immune response. Evidence from environmental monitoring, indoor and occupational exposure studies, and human respiratory-sample and lung-tissue detection studies supports the occurrence of airborne MNPs, the plausibility of inhalation exposure, reported detection in human respiratory samples, and experimental hazard under selected conditions. However, evidence that airborne plastic particles routinely carry bioaerosols or aeroallergens remains insufficient or model-dependent. The aeroplastic exposome is therefore not proposed as a disease entity, validated exposure metric, or established explanation for asthma, chronic obstructive pulmonary disease, fibrosis, infection, or cancer. Instead, it is a framework for organizing testable questions about polymer identity, aerodynamic fraction, morphology, aging state, biological loading, co-exposure context, deposition, clearance, epithelial–immune responses, and host susceptibility. Priority research needs to include standardized airborne sampling, same-particle polymer–bioaerosol–allergen characterization, exposure-relevant aerosol systems, factorial co-exposure experiments, and prospective human studies with repeated personal exposure assessment. Full article

Liquid enzyme formulations are characterized by high water activity, which may adversely affect their storage stability and shelf life. Therefore, their powdered form can significantly improve enzyme stability while facilitating handling, dosing, storage, and transportation. To date, no studies have reported powder production containing cellulolytic enzyme preparations derived from Basidiomycota fungi. This study aimed to evaluate the potential of spray drying of cellulolytic enzyme preparations derived from submerged cultivation of the yellow oyster mushroom (Pleurotus citrinopileatus) and the pink oyster mushroom (Pleurotus djamor). In addition, the impact of conventional high-temperature spray drying (SD) and dehumidified air-assisted spray drying (DASD) to enable lowering of the drying temperature on the cellulolytic activity of the obtained powders was assessed. The obtained powders were comprehensively characterized for physicochemical properties, including moisture content, flowability, particle-size distribution, and particle morphology. In addition, biochemical analyses were performed to determine cellulolytic enzyme activity before and after spray drying. For both drying methods, obtained powders were microbiologically stable (water activity < 0.3) and exhibited good quality characteristics. The drying technique showed no statistically significant effect on enzymatic activity, as confirmed by the plate assay, while producing powders with comparable physical properties. Consequently, conventional high-temperature spray drying (SD) is an adequate method for stabilizing these cellulolytic enzymes, eliminating the need for the less economically reasonable dehumidified air-assisted technique (DASD). Full article

Fine soy protein isolate (SPI) powders exhibit poor handling and reconstitution properties, while excessive liquid loading can destabilize fluidized-bed agglomeration. This study evaluated an outlet-air relative humidity (RH)-triggered binder-diversion strategy during pulsed fluidized-bed agglomeration of SPI. Atomization pressure (0.5, 1.0, and 1.5 bar), nominal binder pump setting (3.8, 4.7, and 5.6 mL·min⁻¹), and operating mode (continuous spraying or RH-triggered control at a 70% set point) were investigated. Under continuous spraying, outlet RH showed an overall increase throughout the 30 min process. RH-triggered operation maintained outlet RH near the set point after threshold attainment by reducing the spray duty cycle to 0.67–0.96. This corresponded to 102.6–131.0 mL of sprayed water per run, approximately 4–33% less than continuous spraying at the same nominal pump setting. Compared with continuous spraying, RH-triggered operation produced a lower mean final moisture content in all nine conditions, a higher mean process yield in seven conditions, higher D₅₀ values in all conditions, and a lower mean particle size span in seven conditions. Agglomeration reduced the packing-derived CI and HR and shortened wetting time relative to raw SPI, whereas the effects of RH-triggered operation on flow indices, wetting time, and dispersibility depended on atomization pressure and effective binder delivery. Because the feedback action changed both cumulative binder addition and spray history, the observed product differences represent the performance of the complete RH-triggered control strategy rather than an independent effect of RH stabilization. The findings demonstrate the feasibility of outlet-RH-based adaptive binder delivery during pulsed fluidized-bed agglomeration of SPI. Full article

The current reuse of blast furnace slag is limited, and the products made from it have low added value and minimal pricing potential. The primary objective of this research is to develop new eco-friendly 3D printing materials using blast furnace slag as the main raw material, simultaneously achieving combined optimization of color appearance and material performance, to increase the reutilization value of slag and address environmental problems caused by slag. Existing studies on slag-based 3D printing materials mainly focus on improving material performance, often neglecting the combined optimization of color and material performance. This study proposes a solution to create colored slag-based 3D printing materials, aiming to break the conventional view of slag waste as simply “black or gray.” This study optimized the particle size distribution of slag-based 3D printing materials using the Andreasen model. The CIELAB color difference formula was applied to reveal how color difference values varied under different mix ratios. Digital image analysis was conducted to evaluate the color characteristics of the specimens and the uniformity of the pigmentation. After 28 days of natural air curing, the color difference ΔE at various measurement points on each colored specimen remained below 3.0, indicating that iron oxide pigments exhibit satisfactory color stability within the slag matrix. To ensure high-quality 3D printing, this study examined the effect of water temperature on the curing time of colored slag-based 3D printing materials. Range analysis results showed that water temperature exerted the most significant influence on setting time (range = 255 s), substantially greater than that of pigment dosage (range = 15 s) and pigment type (range = 5 s). The Herschel–Bulkley constitutive model was used to calculate the flow index of the material. Printing tests confirmed that colored slag 3D printing materials are suitable for extrusion-based 3D printing. The 28-day compressive test results showed that the average fracture load of the three pigmented specimen groups ranged from 23.30 to 24.58 N. Cost analysis further indicated that the comprehensive material cost is approximately 467 RMB/ton, which is lower than that of commercially available colored cement, demonstrating favorable economic competitiveness. The development of colored materials for 3D printing based on blast furnace slag can expand their applications and market potential. It also improves material performance and market acceptance, and its cost advantage over commercial colored cement further enhances its viability for practical applications, promoting high-value recycling and reuse of slag waste. Full article

Background and Clinical Significance: Peri-implantitis is an inflammatory condition associated, among other factors, with biofilm accumulation, affecting peri-implant soft and hard tissues and potentially leading to implant loss. Its treatment remains challenging because no single decontamination or regenerative protocol has demonstrated clear superiority. This case report describes a comprehensive surgical and regenerative approach aimed at preserving an affected implant and restoring peri-implant tissue stability; Case Presentation: A systemically healthy 30-year-old patient presented with peri-implant bone loss around an implant in position 25, restored with a lithium disilicate crown and functioning for three years. Treatment included flap elevation, mechanical debridement and air-polishing of the implant surface, followed by thorough irrigation with sterile saline to remove residual abrasive particles and debris, photodynamic antimicrobial therapy, and laser therapy. Bone regeneration was performed using a bone substitute combined with injectable platelet-rich fibrin to produce sticky bone, which was covered with an advanced platelet-rich fibrin membrane. A provisional crown was placed without occlusal contact. After four months, a definitive crown with a modified emergence profile was delivered to improve hygienic access and reduce biofilm retention. Clinical and radiographic follow-up over five years demonstrated stable peri-implant tissues and maintained bone levels; Conclusions: The combined use of surgical decontamination, PRF-assisted regeneration, sticky bone, and prosthetic modification resulted in stable clinical and radiographic outcomes over five years. Identification and elimination of contributing factors were essential for long-term treatment success. Full article

Gas-assisted discharge of granular materials plays a critical role in shaft furnaces, moving-bed reactors, and other industrial multiphase systems, where interstitial gas flow strongly influences arch stability and may induce progressive flow blockage. Existing analytical models generally neglect aerodynamic gas–particle interactions, whereas CFD–DEM simulations provide high predictive accuracy at the expense of substantial computational cost. To bridge this gap, the present study develops and validates a physically based Torque-Balance Model for predicting gas-assisted granular discharge, arch stability, and flow blockage. A comprehensive experimental investigation was performed using a quasi-two-dimensional transparent apparatus and a thermally stabilized shaft model operated under controlled conditions. Gas-assisted discharge was examined for different gas-flow directions, gas properties, outlet geometries, and particulate materials using hydrogen, helium, and air. High-speed imaging together with gravimetric measurements enabled detailed characterization of discharge regimes and arch evolution. The proposed analytical framework explicitly incorporates interparticle mechanical interactions, aerodynamic drag, outlet geometry, and gas-pressure effects within a unified torque-balance formulation. The model describes successive stages of the discharge process, including stable discharge, transition to blockage, and complete flow suppression, while maintaining computational efficiency suitable for engineering calculations. Experimental results demonstrated that gas-flow direction governs arch stability and discharge behavior. Co-current gas flow promoted repeated arch collapse and enhanced discharge, whereas counter-current flow progressively stabilized the granular arch and ultimately produced complete flow blockage. Validation against the complete experimental database demonstrated excellent agreement between theoretical predictions and experimental observations, yielding an average prediction error below 10%, a maximum deviation within ±20%, and a coefficient of determination of R² = 0.96. The proposed Torque-Balance Model provides a computationally efficient and physically interpretable engineering framework that bridges the gap between simplified empirical correlations and computationally intensive CFD–DEM simulations and can be applied to the prediction and optimization of gas-assisted granular discharge in industrial multiphase systems. Full article

Coal dust carried by open-top freight trains can undergo complex transport and redistribution in confined railway tunnels, where train-induced airflow links in-tunnel particle motion to near-portal dispersion. However, how particle size and source position jointly influence transport across the train–tunnel–portal system remains insufficiently understood. A three-dimensional transient CFD–DPM model was developed for an open-top coal train traveling at 80 km/h through a 200 m local tunnel section and adjoining portal air domains. Four controlled cases combined two prescribed particle sources—a coal-surface source and a near-ground source—with representative diameters of 10 and 350 μm. In the simulated cases, the maximum air speed over the exposed coal surface increased from approximately 24 to 39 m/s during tunnel entry. The 350 μm particles exhibited stronger inertial settling and preferential migration toward the lower tunnel, whereas the 10 μm particles were more strongly coupled to the airflow and transported toward the portal by the train wake. Under the same prescribed source strength, the near-ground-source cases produced higher source-normalized concentration responses than the coal-surface-source cases, indicating a stronger suspended-transport response for particles introduced near the tunnel floor. In the 10 μm near-ground-source case, fine particles passed through the outlet portal and formed a transient elevated plume that spread downstream and laterally. Within the prescribed-input cases examined here, the simulations illustrate the joint influence of particle size and source position on cross-region coal-dust transport and organize the transport pathways into four particle-transport regions: the coal-surface, lower-tunnel, train-wake, and near-portal regions. Full article

The effect of a tendency toward coplanarity of sub-cores in gamma-ray–hadron families, observed in high-mountainous and stratospheric experiments with X-ray emulsion chambers at super-high energies, is discussed. Based on simulations within the framework of the traditional FANSY 2.0/QGSJ model and the radical FANSY 2.0/2D model, the possibility of studying coplanar energy flows in the cores of Extensive Air Showers (EAS) arriving at the surface of the ADRON-55 calorimeter is considered. An assessment of the sensitivity of the ADRON-55 calorimeter for studying the coplanarity effect of energy flows in EAS cores has been made. Full article

Mass concentrations of particulate matter are a fundamental metric for air quality and health impact assessment; however, they are insufficient for accurately characterizing exposure. They do not capture particle size distribution or number concentration. Therefore, aerosol assessment should include particle number concentration (PNC), which better represents toxicologically relevant fractions and enables more precise source identification. The aim of this study was to conduct a comprehensive evaluation of particle number concentration (PNC) measurements in the 0.3–10 µm size range obtained using three low-cost Sensirion SPS30 particle sensors under field conditions in an urban environment. The analyses included an assessment of agreement between the SPS30 sensors, an evaluation of their measurement performance against the OPS 3330 optical particle spectrometer, and the development of calibration models. The SPS30 sensors showed high inter-device repeatability for PNC in the 0.3–1.0 µm range (CV_d < 2%). However, measurement performance declined with increasing particle size, with the index of agreement (IOA) decreasing from 0.8 (0.3–0.5 µm) to −0.5 (2.5–10 µm). Sensor accuracy was influenced by meteorological conditions: relative humidity primarily affected short-term variability (precision and dynamic agreement), while temperature controlled systematic bias. Although incorporating these variables into advanced calibration models improved performance, SPS30 sensors remained unsuitable for PNC measurements in the 2.5–10 µm range, exhibiting systematic errors of ~25% even after nonlinear correction. The findings support the responsible use of low-cost particle sensors for supplementary air quality monitoring, contributing to accessible environmental data and sustainable urban air quality management. Full article