Search Results (452)

Semi-open impeller sewage pumps are widely used for transporting solid-laden fluids due to their anti-clogging properties. However, unlike extensive research on clear water conditions, the specific mechanisms governing pressure instabilities under solid–liquid two-phase flows remain underexplored. This study investigates the unsteady flow field and pulsation characteristics of a Model 80WQ4QG pump using unsteady CFD simulations based on the Standard k−ϵ turbulence model and the Eulerian–Eulerian multiphase model. The effects of flow rate, particle size, and volume fraction were systematically analyzed. Results indicate that the blade-passing frequency (95 Hz) dominates the pressure spectra, with the volute tongue and impeller outlet identified as the most sensitive regions. While increased flow rates weaken fluctuations at the volute tongue, the presence of solid particles significantly amplifies them. Specifically, compared to single-phase flow, the pulsation amplitudes at the volute tongue increased by 68.15% with a 3.0 mm particle size and by 97.73% at a 20% volume fraction. Physically, this amplification is attributed to the intensified momentum exchange between phases and the enhanced turbulent flow disturbances induced by particle inertia at the rotor–stator interface. These findings clarify the particle-induced flow instability mechanisms, offering theoretical guidelines for optimizing pump durability in multiphase environments. Full article

This study addresses the critical packaging requirements of implantable pressure sensors concerning measurement accuracy and environmental stability. We propose a solid/liquid composite packaging technique based on Parylene-C and silicone oil. Utilizing liquid silicone oil as an intermediate medium, this method effectively decouples solid/solid interface shear forces, thereby mitigating measurement errors caused by mechanical coupling. Furthermore, the superior hydrophobic properties of silicone oil and its defect-filling capability are employed to slow the infiltration rate of water molecules at the interface, ensuring long-term stability. The influence of the solid/liquid composite layer on the mechanical properties of the sensor’s sensitive element was analyzed through finite element simulation. The experimental results demonstrate the efficacy of this approach: after adding a liquid silicone oil layer between the Parylene coating and the sensitive element, the sensor’s accuracy improved to 0.5 mmHg within the pressure range encountered in clinical human applications. In simulated bodily fluids, it demonstrated exceptional long-term stability, with drift values consistently below 2 mmHg over a 30-day period. This research provides a feasible and straightforward solution for the packaging design of high-performance implantable pressure sensors. Full article

Efficient thickening of unclassified tailings slurry (UTS) is critical for enhancing mine backfill efficiency and reducing operational costs. Ultrasonic technology has emerged as a promising approach to facilitating the solid–liquid separation process in such slurries. In this study, systematic experiments were conducted using a 20 kHz ultrasonic concentrator. The effects of ultrasonic treatment timing (applied at 0, 5, 10, 15, 20, 25, 30, and 35 min during free settling) and power (50 to 400 W in eight levels) were investigated by monitoring the solid–liquid interface settling velocity and underflow concentration. The key findings are as follows: Ultrasonic application at the 5 min mark yielded the optimal thickening performance, increasing the final mass concentration by 1.3% compared to free settling alone. The average settling velocity generally increased with ultrasonic power (with the exception of 50 W), and the final underflow concentration exhibited a steady rise. Notably, the 400 W treatment induced a significant settlement acceleration, attributed to the formation of drainage channels. Mechanistic analysis revealed that these drainage channels undergo a dynamic process of formation, expansion, contraction, and closure, driven by ultrasonically induced directional water migration, particle compaction, and energy boundary effects. This research not only enriches the theoretical framework of ultrasonic-assisted thickening but also provides practical insights for optimizing mine backfill operations. Full article

The rising levels of Co(II) in aquatic environments present considerable risks, thereby necessitating the development of effective remediation strategies. This study introduces an innovative pre-hydration method for synthesizing carbonated calcined clay dolomite (CCCD) to efficiently remove Co(II) from contaminated water. This pre-hydration treatment successfully reduced the complete carbonation temperature of the material from 500 °C to 400 °C, significantly enhancing energy efficiency. The Co(II) removal performance was systematically investigated by varying key parameters such as contact time, initial Co(II) concentration, pH, and solid/liquid ratio. Optimal removal was achieved at 318 K with pH of 4 and a solid/liquid ratio of 0.5 g·L⁻¹. Continuous flow column experiments confirmed the excellent long-term stability of CCCD, maintaining a consistent Co(II) removal efficiency of 99.0% and a stable effluent pH of 8.5 over one month. Isotherm and kinetic models were used to empirically describe concentration-dependent and time-dependent uptake behavior. The equilibrium data were best described by the Langmuir model, while kinetics followed a pseudo-second-order model. An apparent maximum removal capacity of 621.1 mg g⁻¹ was obtained from Langmuir fitting of equilibrium uptake data. Mechanistic insights from Visual MINTEQ calculations and solid phase characterizations (XRD, XPS, and TEM) indicate that Co(II) removal is dominated by mineral water interface precipitation. The gradual hydration of periclase (MgO) forms Mg(OH)₂, which creates localized alkaline microenvironments at particle surfaces and drives Co(OH)₂ formation. Carbonate availability further favors CoCO₃ formation and retention on CCCD. Importantly, this localized precipitation pathway maintains a stable, mildly alkaline effluent pH (around 8.5), reducing downstream pH adjustment demand and improving operational compatibility. Overall, CCCD combines high Co(II) immobilization efficiency, strong long-term stability, and an energy-efficient preparation route, supporting its potential for scalable remediation of Co(II) contaminated water. Full article

In this study, cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) are employed to systematically investigate surface and wetting properties on hydrophobic surfaces, specifically in mixed solvents composed of ethylene glycol (EG) and water at 298.15 K. By varying the concentration of each surfactant within the EG–water mixture, both surface tension and contact angle measurements are performed to elucidate how surfactant type and solvent composition influence interfacial behavior and wettability. PTFE and wax surfaces were chosen as model hydrophobic surfaces. Surface tension measurements obtained in pure water and in water–EG mixtures containing 5, 10, and 20 volume percentage EG reveal a consistent decrease in the premicellar slope (${\displaystyle \frac{d\gamma }{d\mathit{log}C}}$) with increasing EG content. This reduction reflects weakened hydrophobic interactions and less effective surfactant adsorption at the air–solution interface. The corresponding decline in maximum surface excess (${\Gamma }_{max}$) and increase in minimum area per molecule ($A_{min}$) confirm looser interfacial packing due to EG participation in the solvation layer. Plots of adhesion tension (A_T) versus surface tension (γ) exhibit negative slopes, consistent with reduced solid–liquid interfacial tension (${\Gamma }_{LG}$) and greater redistribution of surfactant molecules toward the solid–liquid interface. AOT shows stronger sensitivity to EG compared to CTAB, reflecting structural headgroup-specific adsorption behavior. Work of adhesion (W_A) measurements demonstrate enhanced wettability at higher EG concentrations, highlighting the cooperative impact of co-solvent environment and surfactant type on wetting phenomena. Full article

The process of bacterial reproduction on surfaces conducive to growth forms colonies, which are defined as physical bodies with functional and environmental effects. This phenomenon can be conceptualized as transforming biological processes into physical phenomena. Large bacterial multicellular aggregates can be conceptualized as physical entities, produced by “colonial organisms”, thereby transforming physics into biology. The formation of colonies requires surfaces, typically hydrogels or liquid–air interfaces, but also hard solid surfaces. Bacterial cell layers also contribute to the production of surfaces. Within a typical 3D-shaped, frequently domed colony, a variety of microcompartments form at the intersections of gradients that diffuse from its aerial and surface limits, leading to cellular functional diversity. This heterogeneity can lead to physical changes and fractures in the colony material, leading to the formation of fluid microchannels. The second primary type of colony is the 2D-shaped form that spreads over larger surfaces and is known as a biofilm. These physical structures possess significant water content, which is retained by a bacterial-excreted exopolymer. Biofilms are structurally organized as multilayer structures that can expand in the space through the lateral slippage of a more fluid overlayer on top of the surface-attached layer. The dissemination of biofilms may entail the integration of additional bacterial colonies, thereby giving rise to complex biofilms. The physical occupancy of microenvironments by colonies created on surfaces of higher organisms or on environmental surfaces exerts a significant influence on fluid mechanics and the functioning of organisms and ecosystems. In addition, colonies also contribute to the pathology of industrial constructions and devices, often leading to microbiologically influenced electrochemical corrosion, which results in material degradation. Full article

The dynamics of gas–liquid two-phase flow at fracture junctions are crucial for optimizing fluid transport in the complex fracture networks of coal seams, particularly for coalbed methane (CBM) extraction and gas hazard management. This study presents a comprehensive numerical investigation of transient air–water flow in a two-dimensional, symmetric, cross-shaped fracture junction. Using the Volume of Fluid (VOF) model coupled with the SST k-ω turbulence model, the simulations accurately capture phase interface evolution, accounting for surface tension and a 50° contact angle. The effects of inlet velocity (0.2 to 5.0 m/s) on flow patterns, pressure distribution, and energy dissipation are systematically analyzed. Three distinct phenomenological flow regimes are identified based on interface morphology and force balance: an inertia-dominated high-speed impinging flow (Re > 4000), a moderate-speed transitional flow characterized by a dynamic balance between inertial and viscous forces (∼1000 < Re < ∼4000), and a viscous-gravity dominated low-speed creeping filling flow (Re < ∼1000). Flow partitioning at the junction—defined as the quantitative split of the total inflow between the main (straight-through) flow path and the deflected (lateral) paths—exhibits a strong dependence on the Reynolds number. The main flow ratio increases dramatically from approximately 30% at Re ∼ 500 to over 95% at Re ∼ 12,000, while the deflected flow ratio correspondingly decreases. Furthermore, the pressure loss (head loss, ΔH) across the junction increases non-linearly, following a quadratic scaling relationship with the inlet velocity (ΔH ∝ V₀^1.95), indicating that energy dissipation is predominantly governed by inertial effects. These findings provide fundamental, quantitative insights into two-phase flow behavior at fracture intersections and offer data-driven guidance for optimizing injection strategies in CBM engineering. Full article

Controlling the rheological properties of liquids allows for the regulation of effective movement, transport of substances, and processes in biological systems. This work presents an experimental investigation into the influence of the proton-exchange polymer membrane Nafion on the surface tension coefficient (STC) of distilled water, aqueous solutions of two methylene blue (MB) forms, and ascorbic acid (AA). Immediately upon membrane immersion in the solutions, a sharp decrease in the surface tension of distilled water, as well as of the oxidized and reduced forms of MB, occurs. The observed narrow time interval is associated with the formation of an exclusion zone near the membrane–solution interface, containing dissociated sulfonate groups $\left(\mathrm{S}{\mathrm{O}}_3^{-}\right)$. The value of the time interval depends on the type of aqueous solution. At long soaking of the membrane in solutions, we obtained: for the aqueous solution of Mb⁺ (blue-coloured solution) the STC value eventually increases by about 5%, and for the reduced form of methylene blue MbH⁰-colourless solution, the STC value decreases by 4%. The STC value of the solutions formed during diffusion into the membrane has a significantly lower value compared to the STC of distilled water by 20% for the Mb⁺ form and by 24% for the MbH⁰ form of MB. The presence of the membrane in the aqueous AA solution causes only an increase in the STC value of the solution. Ultimately, for the solution with a concentration of 5 g/L, this increase reached 15% relative to the STC value of the original AA solution. The change in surface tension of the investigated solutions in the presence of the membrane is due to their adsorption onto the membrane surface. Fourier-transform infrared (FTIR) spectroscopy investigation of distilled water, MB, and AA solution diffusion into the membrane across the range (370–7800) cm⁻¹ confirms the process nonlinearity and enables identification of distinct time intervals corresponding to membrane swelling stages. The positions of IR transmission minima for membranes containing water and solution components remain unchanged; only the numerical values of the transmission coefficients vary. Using spectrophotometry, absorption lines of the membrane with adsorbed components of MB and AA solutions were identified in the range of (190–900) nm. The absorption spectra of dried membranes with adsorbed Mb⁺ and AA solutions show a redshift to the IR region for the Nafion with Mb⁺ and a shift to the UV region for the Nafion soaked in an aqueous ascorbic acid solution. A surface tension gradient at the membrane–solution interface can induce concentration-capillary convection in the liquid. Full article

Bulk nanobubbles (NBs) are remarkably long-lived in liquids, yet the molecular mechanisms underpinning their stability remain unresolved. In this work, 50 ns all-atom molecular dynamics simulations were performed to investigate how gas identity (O₂, N₂, and air with N₂:O₂ = 4:1), initial gas loading, alkalinity (pH 7 and 13), and organic additives (acetic acid/acetate, ethanol/ethoxide, and hexane) influence the stability of 5 nm NBs in water. Stability was evaluated by the percentage of gas atoms retained in the bubble, density profiles, hydrogen-bond statistics, and radial distribution functions. Higher initial gas density markedly enhanced stability, and N₂-NBs consistently outperformed O₂-NBs, consistent with the lower solubility of N₂. Alkaline conditions exerted only a minor stabilizing effect, most pronounced for air-NBs. Organic additives affected stability according to their hydrophobicity: hydrophobic hexane substantially increased gas retention, especially at low gas loading, by promoting gas clustering and re-adsorption at the NB interface, whereas hydrophilic solutes had negligible influence. RDF analyses revealed that this stabilization correlates with weakened gas–water hydrogen bonding and enhanced gas–gas and gas–hexane interactions. These results elucidate the molecular determinants of NB persistence and offer design guidelines for tuning bubble longevity in environmental and industrial systems. Full article

Droplet-based microfluidics offers a promising approach for enhancing heat transfer in microchannels, which is critical for the thermal management of microsystems. This study presents a two-dimensional numerical investigation of flow and heat transfer characteristics of liquid–liquid two-phase droplet flow in a rectangular flow-focusing microchannel. The phase-field method was employed to capture the interface dynamics between the dispersed (water) and continuous (oil) phases. The effects of total velocity and droplet size on pressure drop and heat transfer performance are systematically analyzed. The results indicate that the heat transfer of two-phase droplet flow was significantly enhanced compared to single-phase oil flow, with its maximum heat transfer coefficient being approximately three times that of single-phase oil flow. The average heat transfer coefficient increases with total velocity and exhibits a non-monotonic dependence on droplet size. These findings provide valuable insights into the design and optimization of rectangular flow-focusing droplet-based microfluidic cooling systems. Full article

Raman spectroscopy has become a key tool for resolving the molecular behavior of interfaces due to its non-invasiveness, fingerprinting ability and in situ detection advantages. Surface-enhanced Raman scattering (SERS) and its derivative techniques (including SHINERS and TERS) have significantly overcome the challenges of weak interfacial signals and strong water interference through the synergistic effect of electromagnetic field enhancement and chemical enhancement. They have realized highly sensitive molecular detection at various interfaces such as solid–liquid, gas–liquid, water–oil, and so on. Despite the challenges of substrate stability and signal quantization, the deep integration of multi-technology coupling and theoretical computation will further promote the breakthrough of this technology in interface science. In this review, we systematically review the applications of Raman spectroscopy and SERS techniques in interface resolution, including key research directions such as analyzing interfacial molecular structures, detecting material reactions at water–oil interface, and tracking the evolution of electrochemical interfacial species, as well as exploring the technological bottlenecks and future development directions. Full article

The presence of micro- and nano-plastics in the atmosphere has become evident, necessitating risk assessments for humans. Although submerged culture systems are often used to evaluate the safety of fine particles, some plastics float in culture media owing to their low density. Therefore, developing an air–liquid interface (ALI) system capable of assessing plastic exposure is essential. In this study, we developed a chamber for exposing nanoplastic aerosols to ALI cultures and evaluated their toxicological effects. A glass exposure chamber integrated with a donut-shaped culture plate was constructed. The aerosols were introduced through four upper inlets and discharged through five lower outlets. The culture temperature was controlled by circulating water through the inside space of the plate. A nano-polystyrene (PS) suspension was nebulized and introduced into the chamber. Exposure of co-culture of Calu-3 and U937 cells to nano-PS aerosols resulted in a spatial mass concentration-dependent increase in hydrogen peroxide concentration in the culture medium, elevated expression of inflammatory cytokines and chemokines (including IL-6 and IL-8) in Calu-3 cells and decreased trans-epithelial electrical resistance. These findings indicate that nano-PS aerosol exposure induces oxidative stress and inflammatory responses, leading to alveolar barrier dysfunction. Overall, the developed ALI exposure system provides a useful in vitro culture system for evaluating the safety of nanomaterials, including nanoplastics, and highlights the importance of aerosol-based approaches in assessing the toxicity of respirable particles. Full article

This study quantifies radical pathways and the influence of process variables in a 425 kHz sonoreactor through a coupled calorimetric and multidosimetric approach during Sunset Yellow FCF degradation. Reactive oxygen species were mapped with four complementary dosimeters. Potassium iodide (KI) tracked interfacial hydroxyl radicals (^•OH). KI with ammonium heptamolybdate (AHM) captured ^•OH radicals together with hydrogen peroxide (H₂O₂). Bulk H₂O₂ accumulation integrated the recombination branch. Hydroxylation of 4-nitrophenol to 4-nitrocatechol acted as a selective near-interface ^•OH probe. Calorimetry showed that acoustic power density increased with set power and decreased with liquid height. All four dosimeters rose coherently with this variable, indicating that stronger driving elevated ^•OH generation while channeling a larger fraction into H₂O₂ through recombination. Process studies linked energy delivery to performance across operating conditions. Higher power accelerated pseudo-first order dye decay. Increasing initial dye concentration reduced fractional removal at fixed power, consistent with a radical-limited regime. Acidic media enhanced degradation by maintaining a stronger hydroxyl radical to water redox couple and by improving H₂O₂ persistence. Near neutral and alkaline media exhibited carbonate and bicarbonate scavenging of hydroxyl radicals and faster peroxide loss. Dissolved gas identity strongly modulated activity. Oxygen and argon outperformed air and carbon dioxide due to the combined thermophysical and chemical roles of the bubble gas. The calorimetry anchored and multidosimetric protocol provides a general route to compare reactors, optimize conditions, and support scale-up based on delivered energy density. Ultrasonication-driven degradation is a robust, practical technology for advanced treatment of dye-laden waters. Full article

Wet-snow avalanches constitute a major geomorphic hazard in southeastern Tibet, where warm, humid climatic conditions and a steep, high-relief terrain generate failure mechanisms that are distinct from those in cold, dry snow environments. This study investigates the snowpack conditions underlying avalanche initiation in this region by integrating UAV-based multi-sensor surveys with field validation. Ground-penetrating radar (GPR), infrared thermography, and optical imaging were employed to characterize snow depth, stratigraphy, liquid water content (LWC), snow water equivalent (SWE), and surface temperature across an inaccessible avalanche channel. Calibration at representative wet-snow sites established an appropriate LWC inversion model and clarified the dielectric properties of avalanche-prone snow. Results revealed SWE up to 1092.98 mm and LWC exceeding 13.8%, well above the critical thresholds for wet-snow instability, alongside near-isothermal profiles and weak bonding at the snow–ground interface. Stratigraphic and UAV-based observations consistently showed poorly bonded, water-saturated snow layers with ice lenses. These findings provide new insights into the hydro-thermal controls of wet-snow avalanche release under monsoonal influence and demonstrate the value of UAV-based surveys for advancing the monitoring and early warning of snow-related hazards in high-relief mountain systems. Full article

Metal anodes promise improvements in energy density and cost; however, their performance is determined within the first several nanometers at the interface. This review reports on how polymer-based artificial solid electrolyte interphases (SEIs) are engineered to stabilize Li and aqueous-Zn anodes, and how these designs are now evaluated against operando readouts rather than post-mortem snapshots. We group the related molecular strategies into three classes: (i) side-chain/ionomer chemistry (salt-philic, fluorinated, zwitterionic) to increase cation selectivity and manage local solvation; (ii) dynamic or covalently cross-linked networks to absorb microcracks and maintain coverage during plating/stripping; and (iii) polymer–ceramic hybrids that balance modulus, wetting, and ionic transport characteristics. We then benchmark these choices against metal-specific constraints—high reductive potential and inactive Li accumulation for Li, and pH, water activity, corrosion, and hydrogen evolution reaction (HER) for Zn—showing why a universal preparation method is unlikely. A central element is a system of design parameters and operando metrics that links material parameters to readouts collected under bias, including the nucleation overpotential (η_nuc), interfacial impedance (charge transfer resistance (R_ct)/SEI resistance (R_SEI)), morphology/roughness statistics from liquid-cell or cryogenic electron microscopy (Cryo-EM), stack swelling, and (for Li) inactive-Li inventory. By contrast, planar plating/stripping and HER suppression are primary success metrics for Zn. Finally, we outline parameters affecting these systems, including the use of lean electrolytes, the N/P ratio, high areal capacity/current density, and pouch-cell pressure uniformity, and discuss closed-loop workflows that couple molecular design with multimodal operando diagnostics. In this view, polymer artificial SEIs evolve from curated “recipes” into predictive, transferable interfaces, paving a path from coin-cell to prototype-level Li- and Zn-metal batteries. Full article