Search Results (2,375)

Sewerage systems are a main element of a city’s infrastructure. Roughness coefficients are fundamental parameters for sewage system operation. The intermittent nature of the flow leads to the appearance of deposits that become an integral part of the sewerage systems. Deposited material not only leads to the loss of hydraulic capacity and decreases the concentration of dissolved oxygen (which is found in direct relation to all quality parameters), but it also results in more transported particles being intercepted. In the design calculations, the roughness coefficient is estimated rather than calculated. It has been demonstrated that the estimation of stress within and above roughness elements improves the predictive capability for the concentration of suspended sediment. In this study, we focused on a local evaluation of the roughness coefficient when the flow velocity is below the minimum self-cleansing velocity. Some authors consider the selection of the most reliable method for estimating bed shear stress to be the main challenge. Other authors have suggested that all possible methods should be applied simultaneously to achieve a reliable bed shear stress estimation, knowing that the roughness coefficient can be determined through the shear boundary stress. We calculate the local roughness coefficient in Manning’s equation using a laboratory model, considering clear water flowing over a solid boundary with consolidated deposits, represented by artificial roughness elements (calibrated hemispheres). The European standard EN 752:2017 specifies a minimum average cross-sectional velocity of 0.7 m/s for pipe self-cleansing. This study established the range of possible roughness coefficient values when the minimum velocity design criterion is not met. The second criterion was to consider acceptable a sediment deposit occupying between 1% and 2% of the collector diameter. Velocity distributions around artificial roughness and statistical parameters of the turbulent flow were obtained using a PIV system. Five methods were implemented and the range of roughness coefficient values varied between 0.007 and 0.023. This variation is closely related to sewer performance. We selected the dissipation method as the primary reference for this study, as it is most closely aligned with the underlying physics of flow over roughness elements. This approach allows for robust validation by correlating multiple characteristic mechanisms of the turbulent cascade. Full article

This study evaluates the effectiveness of microfine cement (MF) to seal two laboratory-fabricated wellbore microannuli. The samples were characterized with their hydraulic apertures (158 and 85 µm). A rough cement surface paired with a transparent acrylic plate, acting as a steel surrogate, formed the basis of the experimental setup, with the acrylic enabling direct visual monitoring of MF behavior throughout the tests. Hydraulic aperture measurements were taken before and after each repair attempt, with MF injected at constant pressure and a 24 h curing period allowed between successive injections. Four injection cycles were completed per sample. The MF cement had a d₉₅ = ~14 µm and a w/c of 1.45. Results show progressive reduction in hydraulic aperture from 158 µm to 20 µm and from 85 µm to 8 µm, but complete sealing was not achieved. Visual observations revealed that bleeding and filtration (plug formation) were the primary mechanisms limiting repair efficiency. These findings highlight the challenges of sealing rough microannuli with MF and suggest that aperture variability and particle filtration strongly influence repair outcomes. Higher injection pressures or alternative materials may be required for complete sealing. Full article

Biomass combustion, as a key technology for achieving a low-carbon transformation of the energy system, faces multiple challenges in its efficient and clean utilization, including the high heterogeneity of fuels, the complex multi-scale coupling of the combustion process, and the attainment of ultra-low emissions. Traditional research methods have significant disconnections between microscopic mechanism understanding, macroscopic performance prediction of reactors, and end-of-pipe pollution control, which restricts the improvement of system performance. This review presents recent advances in advanced numerical simulation, pollutant control strategies, and bioenergy with carbon capture and storage (BECCS) pathways targeting ultra-low emissions in biomass combustion. This work synthesizes progress across three interconnected domains. First, methodologies are examined for integrating detailed chemical kinetics, particle-scale models, and reactor-scale simulations to develop high-fidelity predictive tools. Second, low-nitrogen combustion and synergistic pollutant control strategies for primary furnace types (e.g., grate, fluidized bed) are evaluated, alongside process optimization from fuel pretreatment to flue gas purification. Third, the potential for integrated design of biomass energy systems with carbon capture is assessed, emphasizing that system efficiency hinges on holistic “fuel-combustion-capture” chain optimization rather than isolated unit improvements. Future research directions are highlighted, including the development of physics-informed AI modeling paradigms, deeper co-design of multiple processes, and the establishment of robust life-cycle assessment frameworks. This review aims to provide a structured reference to inform both fundamental research and the practical development of next-generation clean biomass combustion technologies. Full article

This article presents a literature review aimed at outlining the state of the art in the assessment of underwater noise and in the evaluation of its effects on fish behavior and health. We examine current methodologies for characterizing the underwater soundscape, emphasizing the importance of incorporating particle motion sensors alongside pressure sensors due to the nature of fish auditory systems. Guidelines for simulating underwater acoustic environments in laboratory settings are also summarized. To characterize anthropogenic noise sources, we consider ship propellers as the primary source of continuous underwater noise, whereas we consider the equipment used in marine seismic surveys as the primary source of impulsive underwater noise. Finally, we summarize documented effects of acoustic pollution on a commercially important species, European seabass (Dicentrarchus labrax), and describe experimental setups suitable for observing these effects. Full article

Inhalation is a primary route of exposure to engineered nanomaterials (ENMs), enabling particles to penetrate deeply into the lungs and subsequently leading to adverse health effects. Human health risk assessment addresses the potential risk posed by ENMs. The aim was achieved by measuring the emissions of ENMs using real-time instrumentation and subsequently applying the data to evaluate associated human health risks using ModelRisk. Emissions during the synthesis of silver nanoparticles (AgNPs), gold nanoparticles (AuNPs), graphene 2D (G2D) nanomaterials, multiwalled carbon nanotubes (MWCNT) and the application of AuNPs on black carbon electrodes were monitored using a NanoScan SMPS Model 3910 and Optical Particle Sizer (OPS) Spectrometer Model 3330. The derived mass-based time-weighted average concentrations were reported for AgNPs and MWCNTs in comparison with occupational exposure limits (OELs). AgNP concentrations of 0.36 µg/m³ and 3.99 µg/m³ for the NanoScan SMPS and OPS, respectively, exceeded the OEL of 0.19 µg/m³, whereas MWCNT concentrations (0.261 µg/m³) remained below the OEL of 1 µg/m³. AuNP synthesis resulted in particle number concentrations exceeding the provisional nano reference value of 20,000 particles/cm³ for the OPS data (3.74 × 10⁴ particles/cm³), whereas application of AuNPs on carbon black electrodes was below this limit. Although no OEL exists for graphene, risk estimates indicated potential adverse health effects like those observed for AgNPs, AuNPs, and MWCNTs. Measured exposure concentrations were applied in a human health risk assessment model, highlighting ENM concentration as a key determinant of risk. These findings emphasise the need for continuous monitoring, further risk assessment studies, and proactive risk management strategies. Full article

Oil analysis is one of the main means to obtain the working status of important friction pairs in ship and Marine engineering equipment at present. Analyzing the wear mechanism by analyzing the particle size, morphology, properties and other characteristics of metal abrasive particles in the oil is an important basis for achieving health monitoring and scientific maintenance of ship and Marine engineering equipment. Classifying the abrasive particles in the oil according to their particle size is an important step in sample pretreatment. This paper proposes a two-stage sorting microfluidic chip for wear debris based on magnetophoresis. By setting up external permanent magnets in a stepwise manner in the primary and secondary sorting areas, gradient magnetic fields of different magnitudes were formed. The effects of different sample flow rates, sheath fluid flow rates and sheath flow ratios on the pre-focusing before sorting and the sorting effect were studied. The primary sorting of ferromagnetic metal wear particles larger than 50 µm and the secondary sorting of those smaller than 50 µm have been achieved. The primary sorting can serve as an early warning for abnormal equipment wear, while the secondary sorting can provide data support for the scientific formulation of maintenance plans based on equipment requirements. This work provides a new idea and method for the rapid determination of lubricating oil contamination in engineering equipment. Full article

Mechanical pretreatment techniques are essential for overcoming lignocellulosic biomass recalcitrance in emerging biorefineries. This review critically synthesizes advances from 2020 to 2025 across fundamental mechanisms, hybrid technologies, energy efficiency, Life Cycle Assessment, and industrial scalability. The analysis reveals that effective pretreatment targets supramolecular modification—defect generation in cellulose crystallites and the creation of reactive sites—beyond simple particle size reduction. Impact–shear regimes prove most effective for fibrous materials. Hybrid approaches are examined: mechanocatalysis enables solvent-free depolymerization, while mechanoenzymatic technologies achieve hydrolysis without bulk water, though enzyme denaturation under mechanical stress remains unresolved. Energy consumption is the primary upscaling barrier, with Life Cycle Assessment identifying electricity use as the dominant environmental hotspot and emphasizing burden per unit of final product as the critical metric. Technology Readiness Level assessment provides a strategic framework: continuous extruders and mills are industrially mature for bulk applications, while high-intensity batch devices are suited for high-value coproducts. A research agenda prioritizing mechanistic understanding, hybrid process engineering, feedstock diversification, and embedded sustainability assessment is proposed. Full article

The nanoparticles processed from non-edible crop materials and residues have evoked great use in the food and non-food industry. The diversity in agricultural waste biomass and differences in extraction techniques account for variations in end-product properties, and would require examination of waste crop types (source) to determine suitability for the production of cellulose, nanocellulose and graphene particles. This review showed that screening criteria of end-user properties include chemical composition, cellulose contents, morphology, crystallinity, thermal stability, rheology, surface charge and zeta potential. The literature shows that the end-user properties vary with plant source (that is crop type) and extraction techniques. In this review, the cellulose content and percentage crystallinity are primary parameters for selecting agricultural waste biomass for the production of nanocellulose and nanofibrils. Additionally, zeta potential and surface charge can determine polymer interaction for suitability in industrial applications. Moreover, nanocellulose and biochar were found to have various industrial applications as ingredients in the production of food packaging including active packaging, rheological modifiers and thickeners. Pyrolysis is the eminent strategy for the transformation of agricultural waste into biochar-derived nanoparticles and carbon-rich materials. Full article

The study investigates the microstructure evolution in the stir zone produced by the friction stir processing (FSP) of a heat-treated microalloyed Al-Mn-Cu alloy in the area subjected to the highest temperature, strain, and strain rate. The samples were studied using electron microscopy and atom probe tomography (APT) to obtain structural and chemical information from the macro to the nano scale. FSP refines the dendritic Al-rich solid solution grains through dynamic recrystallisation in the range of a few micrometres. The primary intermetallic phases were dispersed to the particles in the 0.5–3 µm range and transformed mainly into a more stable τ₁-Al₂₉Mn₆Cu₄ phase. The fraction of dispersed particles after FSP increased due to the precipitation from the solid solution during cooling. The nanoscale quasicrystalline precipitates in the matrix, formed upon heat treatment, dissolved entirely during FSP, while the strong coarsening of the L1₂ precipitates occurred due to high temperatures in the stir zone. After FSP, the hardness of the stir zone was nearly identical for specimens in the as-cast and heat-treated conditions. Full article

To achieve precise control over droplet size and generation frequency in the granulation process of HNS-IV, this study introduces a novel droplet granulation strategy that utilizes pulsed air-jet shearing technology. This approach enables independent and precise regulation of droplet injection frequency (fg) and volume (V) through systematic adjustments of air pressure (P), frequency (fp), duty cycle (η), and liquid flow rate (Q). By controlling the suspension flow rate (Q), we successfully achieved primary particle size control, obtaining median particle sizes (D50) of 375.84 μm, 444.45 μm, and 504.22 μm in ascending order. Furthermore, we systematically investigated the influence of calcium alginate (CA) concentration on both the sphericity of the resultant particles and the thermal decomposition characteristics of HNS microspheres. Our findings demonstrate that while increased CA content enhances particle sphericity, it simultaneously affects the thermal decomposition behavior of the microspheres. The proposed pulsed air-jet shearing method offers significant advantages by significantly reducing the accumulation of volatile organic solvents typical of liquid–liquid biphasic systems. Furthermore, the residual non-toxic aqueous solutions can be easily managed, establishing a greener, safer, and highly controllable approach for HNS-IV granulation. This methodology presents a valuable reference for achieving precise and controllable granulation of various energetic materials. Full article

The impact of large boulders transported by debris flows is a primary cause of structural damage to mitigation works. However, quantitative modeling remains difficult because of the scarcity of field measurements and the complexity of the flow medium. In this study, a theoretical model for boulder impact force in debris flows is developed using dimensional analysis based on the Buckingham theorem, subsequently simplified to two dimensionless parameters, and then validated through a series of controlled laboratory experiments. Marble spheres were used as impactors and were released to strike a rigid steel plate under three types of media: clear water, bentonite slurry, and debris flows containing particles of different size classes. The experiments were designed to isolate and quantify the influence of the flow rheology and the suspended solid phase on impact forces. The results show that the impact coefficient c is strongly governed by the debris flow yield stress, bulk density, and the size of suspended particles, following the relationship c = 0.183[τ/(rgd₁)]^−0.1(d/d₀)^0.05. Based on this relationship, a generalized formula for calculating boulder impact forces in debris flows is proposed. The model is further evaluated using field monitoring data from Jiangjiagou, Yunnan Province. The back-calculated boulder diameters fall predominantly within the range of 0.1–0.3 m (76.3–86.8%), which is consistent with field observations. These results indicate that the proposed model captures the essential physical mechanisms governing boulder impacts and provides a rational basis for selecting design parameters in debris flow mitigation engineering. The array-type piezoelectric impact sensing system designed in this study achieves high-precision and high-stability measurement of the impact force of large boulders in debris flows, providing a new sensing technology for debris flow impact monitoring. Full article

The widespread commercialization of wireless chargers for electric vehicles generally suffers from one main problem, which is the perfect alignment between the two coils, leading to a decrease in mutual inductance, which causes a drop in magnetic coupling and even a failure to transfer power. To address this persistent problem, this work proposes a comprehensive and integrated method for optimizing the coils and control architecture for reliable and safe battery charging. To address the challenges of a complex, nonlinear design space and the need for misalignment-tolerant geometries, we employ a memetic algorithm (MA) that hybridizes Particle Swarm Optimization (PSO) for broad global exploration with Mesh Adaptive Direct Search (MADS) for precise local refinement. This combination effectively avoids poor local solutions—a limitation of standalone PSO or GA approaches reported in recent studies—while efficiently converging to coil geometries that maintain strong magnetic coupling under misalignment. After the coils have been designed, electromagnetic validation is tested using finite element analysis (FEA), which allows the magnetic field distribution to be evaluated, as well as the coupling coefficient under different scenarios of misalignment and variation in the air gap between the ground side and the vehicle side. At the same time, a comprehensive control strategy for the primary side of the system has been developed. This control method ensures power management on the primary side, enabling system interoperability for charging multiple types of vehicles, as well as reducing vehicle weight for greater range. All this is combined with an innovative pulsed current charging method, chosen for its advantages in terms of thermal stability, ensuring safe and efficient recharging that is mindful of battery health. Simulation and experimental validation demonstrate that the proposed framework maintains stable wireless power transfer and achieves over 87% DC–DC efficiency under lateral misalignments up to 100 mm, fully complying with SAE J2954 alignment tolerance requirements. Full article

Unmanned Aerial Vehicle (UAV) fertilization is important for precision agriculture. However, multi-rotor UAVs show a lot of inconsistencies in homogeneity and unclear deposition patterns when they spread granular fertilizer in different operational situations. This study utilized the DJI T40 UAV to measure discharge rates and create a correlation model. An orthogonal design combined DEM simulation with field experiments to look at how flight height and disc speed affected spreading uniformity and effective swath for single and overlapping flight paths. The discharge rate has a strong linear relationship with control parameters (R² > 0.94), which means that it is very easy to predict for all particle sizes. Single-pass deposition shows an “M-shaped” bimodal profile with particles of different sizes arranged in a radial pattern. The best values for H and n were found to be 7 m and 1200 rpm, respectively, and gave a 10 m effective swath width and a coefficient of variation (CV) of 13.79%. Deposition patterns change nonlinearly with flight height and disc speed. Particle size consistency is critical for distribution stability, with flight height being the key quality determinant and particle size variation the primary source of instability. Full article

The objective of this study was to use plant models, Allium cepa and Lepidium sativum, to assess the genotoxic effects of the urban particulate matter (PM) collected in a Northern Italian town. Aqueous extracts of different particle sizes (PM_10–3, PM_3–0.5, PM_0.5) were tested alongside the organic extracts through the standard Ames test. The organic particulate matter extracts were subjected to mutagenicity testing in the Salmonella typhimurium strains TA98 and TA100 (without and with metabolic activation), whereas the aqueous extracts were evaluated for genotoxicity in the emerging seedlings of L. sativum and in the root tips of A. cepa bulbs using the comet test to detect the primary DNA damage. Furthermore, the micronuclei frequency was assessed in the bulbs of A. cepa. As expected, the organic extracts of PM_3–0.5 and PM_0.5 induced point mutations in bacteria. The aqueous extracts of the finest fractions caused a significant increase in genotoxic damage in both plant models. These findings indicate that the two plant models (L. sativum seeds and A. cepa bulbs) are able to detect the genotoxicity of aqueous extracts of air pollutants, with many potential advantages as screening-level tools to complement Ames testing for an easier assessment of urban air quality in terms of DNA toxicity. Full article

Neutrophil extracellular traps (NETs) critically influence thrombosis by promoting platelet aggregation, fibrin formation, and thrombus stabilisation. However, primary human neutrophils present experimental limitations, including short lifespan ex vivo and ethical concerns. In this article, we discuss the available data on PLB-985 cells, a neutrophil-like model with potential to replace human neutrophils in research. Additionally, we present novel structural comparisons showing that both PLB-985- and human neutrophil-derived NETs significantly increased fibrin fibre thickness compared to thrombin-only controls, with similar fibre morphology across conditions. Notably, we also see spherical particles resembling microvesicles within PLB-985-derived NETs, suggesting potential additional procoagulant effects via microvesicle-associated tissue factor level in these cells. New and existing data presented in this article suggest that differentiated PLB-985 cells are able to effectively replicate key structural and functional aspects of human neutrophil NETs. These observations support the use of PLB-985 cells as an ethical, reproducible, and practical alternative for in vitro studies of NETs. Further characterisation is required to determine differences between human neutrophils and neutrophil-like models in macrovesicle formation and implication in NET-related thrombosis research. Full article