Search Results (68)

This study aimed to optimize the spray-drying (SD) process for aquafaba and compare the physical and techno-functional properties of the resulting powder with those of its freeze-dried (FD) counterpart. A Box–Behnken design was employed to evaluate the effects of inlet air temperature (150–190 °C), air speed (3.5–4.3 m/s), and feed flow rate (0.3–0.5 L/h) on 14 quality responses. The optimized SD conditions were determined to be an inlet air temperature of 189 °C, an air speed of 4.2 m/s, and a feed flow rate of 0.3 L/h. Validation experiments demonstrated that the developed models had high predictive capacity, with only a small discrepancy (0.56–5.88%) between the predicted and experimental values. Comparative analysis showed that the optimized SD powder had significantly lower moisture content (2.47%) and water activity (0.18) than the FD powder (3.51% and 0.34, respectively), indicating superior storage stability. In addition, the SD powder exhibited greater whiteness (82.37), higher water solubility (88.44%), and substantially greater foaming capacity (266.67%) than the FD sample (243.33%). Although the FD powder demonstrated better wettability and water absorption capacity because of its porous structure, FTIR spectroscopy and protein secondary structure analysis confirmed that SD preserved the functional integrity of aquafaba. Specifically, SD induced a transition from disordered random-coil structures to more ordered β-sheet and β-turn configurations, thereby improving foaming performance. Overall, these findings indicate that optimized spray-drying is a highly efficient and industrially scalable alternative to freeze-drying for producing functional aquafaba powder for use as a plant-based egg substitute. Full article

Understanding pore-scale interactions among CO₂, the aqueous phase, and heavy oil is crucial for optimizing surfactant-assisted CO₂-enhanced oil recovery. In this study, a three-phase volume-of-fluid (VOF) framework is established in OpenFOAM to simulate immiscible displacement in two-dimensional porous media composed of circular solid grains. Two pore geometries are considered: a relatively uniform geometry and a preferential-channel geometry designed to promote early breakthrough. Sixteen injection schemes are compared, including pure CO₂ flooding, ordinary-water flooding, surfactant–water flooding, aqueous-phase preflush followed by CO₂ injection, and cyclic aqueous-phase/CO₂ injection with different aqueous-slug durations and switching frequencies. The effects of pore geometry, injection strategy, capillary number, viscosity ratio, interfacial tension, and wettability are evaluated using pore-volume-normalized oil recovery, breakthrough PV (the ratio of injected volume to pore volume), cumulative injected CO₂ PV at breakthrough, and phase-distribution indicators. The results show that pore geometry strongly affects macroscopic sweep and breakthrough behavior. In the preferential-channel geometry, pure CO₂ flooding and continuous ordinary-water flooding suffer from early breakthrough and poor sweep, whereas continuous surfactant–water flooding maintains high recovery because reduced oil–water interfacial tension and a more water-wet wall condition promote oil-film detachment and residual-oil mobilization. At 2.5 injected PV, the high-frequency short-slug and 1 s surfactant–water cyclic schemes give the highest or near-highest recovery in the relatively uniform geometry, while continuous surfactant–water flooding remains the highest-recovery scheme in the preferential-channel geometry. Considering the higher chemical demand of continuous surfactant injection and the carbon-utilization objective of CO₂-EOR, the combined surfactant–water/CO₂ schemes are evaluated to clarify the coupling between surfactant-induced oil mobilization and CO₂ displacement. Surfactant–water preflush followed by CO₂ injection becomes more effective as the preflush duration increases, and its recovery advantage over ordinary-water preflush is especially large in the preferential-channel geometry. However, the increase in CO₂ breakthrough PV in this geometry is limited compared with the recovery increment, indicating that the main benefit of surfactant–water is not only delayed gas breakthrough but also enhanced microscopic oil mobilization in poorly swept regions. Increasing the switching frequency slightly improves the cyclic response in the relatively uniform geometry under the tested schedules, whereas all cyclic schemes remain strongly constrained by reconnection with the dominant gas pathway in the preferential-channel geometry. Within the present idealized immiscible VOF model, these comparisons provide a controlled pore-scale comparison for distinguishing surfactant-induced residual-oil mobilization from CO₂ gas-channeling effects in heavy-oil porous media. Full article

The wettability of dust is fundamental to its dispersion and control in mining operations. Current research, however, focuses largely on isolated properties, leaving the synergistic mechanisms of multi-scale factors-such as particle size, morphology, and surface chemistry-poorly understood. This study integrates field measurements, laboratory characterization, and theoretical analysis to investigate the spatial distribution and wetting behavior of dust in fully mechanized mining faces. The results show that respirable dust preferentially accumulated in mechanically disturbed and personnel-exposure zones. At the shearer operator’s station, respirable dust concentrations reached 328.6 mg/m³ in Mine A and 278.4 mg/m³ in Mine B, which were 1.8 and 1.6 times higher than those at the shearer cutting point, respectively. Mine A dust also showed poorer wettability, with a higher water contact angle of 148.9° ± 2.1° compared with 134.7° ± 1.8° for Mine B, mainly due to its larger agglomerates, rougher surface morphology, and more hydrophobic surface chemistry. Accordingly, targeted development pathways for spray and foam technologies are outlined, including compound wetting agents and micro-nano enhanced foaming systems. The integrated multi-scale framework linking concentration, particle size, morphology, surface chemistry, and wettability provide an application-oriented basis for understanding coal mine dust behavior and for supporting more precise and intelligent dust-control strategies. Full article

Tight oil reservoirs are widely recognized as a critical successor in global unconventional energy development and are generally characterized by distinct geological features, including fine pore throats, pronounced heterogeneity, and a high concentration of clay minerals (e.g., montmorillonite and mixed-layer illite/smectite). Severe hydration, swelling, and fines migration are readily induced during water injection or conventional water-based fluid operations, thereby resulting in irreversible impairment of reservoir permeability. Despite the excellent injectivity and capacity for viscosity reduction associated with CO₂ flooding, sweep efficiency is severely compromised by viscous fingering and gas channeling, which are induced by the inherent low viscosity of the gas. While CO₂ foam technology is widely acknowledged as a pivotal solution for addressing mobility control challenges, its implementation is hindered by a primary technical bottleneck: the incompatibility between traditional water-based foam systems and strongly water-sensitive reservoirs. A dual challenge comprising water injectivity constraints and gas channeling is presented by strongly water-sensitive tight oil reservoirs. To address these impediments, three emerging low-damage CO₂ foam systems are critically evaluated in this review. First, the synergistic mechanisms of novel quaternary ammonium salts and polymers in inhibiting clay hydration and enhancing foam stability within modified water-based systems are elucidated. Next, the physical isolation strategy of substituting the water phase with a non-aqueous phase (oil/organic solvent) in organic emulsion systems is analyzed, highlighting advantages in wettability alteration and the mitigation of water blocking. Finally, the prospect of waterless operations using CO₂-soluble foam systems—wherein supercritical CO₂ is utilized as a surfactant carrier to generate foam or viscosify fluids via in situ formation water—is discussed. It is revealed by comparative analysis that: (1) Modified water-based systems are identified as the most economically viable option for reservoirs with moderate water sensitivity, wherein cationic stabilizers are utilized to inhibit hydration; (2) Superior wettability alteration and the elimination of aqueous phase damage are provided by organic emulsion systems, rendering them ideal for ultra-sensitive, high-value reservoirs, despite higher solvent costs; (3) CO₂-soluble systems are recognized as the future direction for “waterless” flooding, specifically tailored for ultra-tight formations (<0.1 mD) where injectivity is critical. Current challenges, such as surfactant solubility, high-temperature stability, and cost control, are identified through a comparative analysis of these three systems with respect to structure-activity relationships, rheological properties, damage control capabilities, and economic feasibility. What is more, an outlook is provided on the molecular design of future environmentally sustainable, cost-effective CO₂-philic materials and smart injection strategies. Consequently, theoretical foundations and technical support are established for the efficient exploitation of strongly water-sensitive tight oil reservoirs. By bridging the gap between reservoir damage control and mobility enhancement, this study identifies viable strategies for enhanced oil recovery. Crucially, it supports carbon neutrality and sustainable energy targets via CCUS integration. Full article

The aim of this work is to develop structurally enhanced and highly hydrophobic polyurethane (PU) foams for the efficient remediation of liquid organic pollutants. For this purpose, PU foams were modified with renewable activated biochar derived from marine algae (AC) and a hydrophobic polydimethylsiloxane (PDMS) coating, producing four systems: pristine PU, PU-AC, PU/PDMS, and the hybrid PU-AC/PDMS composite. The study evaluates how AC incorporation and PDMS surface functionalization influence the microstructure, chemical composition, wettability, thermal stability, and sorption behavior of the foams. SEM images revealed progressive reductions in pore size from 420 ± 80 μm (PU) to 360 ± 85 μm (PU-AC/PDMS), with AC introducing heterogeneity while PDMS preserved open-cell morphology. FTIR confirmed the presence of urethane linkages, carbonaceous structures, and PDMS siloxane groups. Surface hydrophobicity increased markedly from 88.53° (PU) to 148.25° (PU-AC/PDMS). TGA results showed that PDMS improved thermal stability through silica-rich char formation, whereas AC slightly lowered degradation onset. Sorption tests using petroleum-derived oils and hydrophobic organic liquids demonstrated a consistent performance hierarchy (PU < PU/PDMS < PU-AC < PU-AC/PDMS). The ternary composite achieved the highest uptake capacities, reaching 44–56 g/g for oils and up to 35 g/g for hydrophobic solvents, while maintaining reusability. These findings demonstrate that combining activated biochar with PDMS significantly enhances the functional properties of PU foams, offering an efficient and sustainable material for oil–water separation and organic pollutant remediation. Full article

With the advancement of aerospace equipment toward high-speed and heavy-duty applications, conventional forced lubrication systems are facing significant challenges in terms of reliability and adaptability to complex operating conditions. Porous medium materials, owing to their unique self-lubricating and oil-retention capabilities, are regarded as an ideal lubrication solution. However, their seepage behavior is governed by the strong coupling effects of microscopic pore structures and fluid physicochemical properties, the mechanisms of which remain inadequately understood, thereby severely constraining the design and application of high-performance lubricating materials. To address this, this paper systematically reviews recent research progress on seepage behavior in porous media, with the aim of establishing a correlation between microstructural characteristics and macroscopic performance. Starting from the characterization of porous media, this work comprehensively analyzes the structure–seepage relationships in porous polymers, metal foams, and porous ceramics, and constructs a multi-scale theoretical framework encompassing macroscopic continuum theories, mesoscopic lattice Boltzmann methods (LBM), pore network models, and microscopic molecular dynamics. The advantages and limitations of experimental measurements and numerical simulation approaches are also compared. In particular, this study critically highlights the current neglect of key interfacial parameters such as surface wettability and pore roughness, and proposes an in-depth investigation into the seepage mechanisms of polyimide porous cage materials based on LBM. Furthermore, the potential application of emerging research paradigms such as data-driven approaches and intelligent computing in seepage studies is discussed. Finally, it is emphasized that future efforts should focus on developing deeply integrated cross-scale simulation methodologies, strengthening multi-physics coupling and artificial intelligence-assisted research, and advancing the development of intelligent porous lubricating materials with gradient structures or stimulus-responsive characteristics. This is expected to provide a solid theoretical foundation and technical pathway for the rational design and optimization of high-performance lubrication systems. Full article

The aim of this study was to evaluate the effect of surface modification of porous hyaluronic acid (HA)-based materials with a titanium dioxide (TiO₂) layer deposited via atomic layer deposition (ALD) on the selected structural, physicochemical, and antimicrobial properties of materials intended for applications in regenerative medicine. The obtained HA-based materials, enriched with silk and elastin, were analyzed in terms of their rheological behavior, wettability, solubility, and resistance to colonization by clinically relevant bacterial pathogens (Staphylococcus aureus, Klebsiella pneumoniae) and environmental filamentous fungi (Aspergillus niger, Chaetomium globosum). The results demonstrated that even a thin, continuous TiO₂ layer formed after 200 ALD cycles reduced the hydrophilicity of the foams, indicating improved durability in aqueous environments. Microbiological tests confirmed enhanced antimicrobial properties of the foams after TiO₂ modification—showing inhibition of both tested bacterial strains and C. globosum within 24 h. These findings suggest that surface functionalization of hyaluronic acid-based foams with a TiO₂ layer can improve both their environmental stability and, to some extent, reduce microbiological risk, while preserving the layered-porous structure of the foams, which is advantageous for biomedical applications. Full article

This work presents a multifactorial strategy for reusing waste thermoplastics and generating multifunctional filaments for additive manufacturing. Acrylonitrile–butadiene–styrene (ABS) waste and commercial poly(methyl methacrylate) (PMMA) were compounded with carbon black (CB), graphene (G), or graphene foam (GF) at different loadings and extruded into composite filaments. The aim is to couple filler-induced bulk modifications with atmospheric pressure plasma jet (APPJ) surface coatings of TiO₂ and graphene oxide (GO) to obtain waste-derived filaments with tunable morphology, wettability, and thermal stability for advanced 3D-printed architectures. The filaments were subsequently coated with TiO₂ and/or GO using an APPJ process, which tailored surface wettability and enabled the formation of photocatalytically relevant interfaces. Digital optical microscopy and SEM revealed that CB, G, and GF were reasonably well dispersed in both polymer matrices but induced distinct surface and cross-sectional morphologies, including a carbon-rich outer crust in ABS and filler-dependent porosity in PMMA. For ABS composites, static contact-angle measurements show that APPJ coatings broaden the apparent wettability window from ~60–80° for uncoated filaments to ~40–50° (TiO₂/GO) up to >90° (GO), corresponding to a ≈150% increase in contact-angle span. For PMMA/CB composites, TiO₂/GO coatings expand the accessible contact-angle range to ~15–125° while maintaining surface energies around 50 mN m⁻¹. TGA/DSC analyses confirm that the composites and coatings remain thermally stable within typical extrusion and APPJ processing ranges, with graphene showing only ≈3% mass loss over the explored temperature range, compared with ≈65% for CB and ≈10% for GF. Fused deposition modeling trials verify the printability and dimensional fidelity of ABS-based composite filaments, whereas PMMA composites were too brittle for reliable FDM printing. Overall, combining waste polymer reuse, tailored carbonaceous fillers, and APPJ TiO₂/GO coatings provides a versatile route to design surface-engineered filaments for applications such as photocatalysis, microfluidics, and soft robotics within a circular polymer manufacturing framework. Full article

Edible coatings are widely used to modulate oil uptake and moisture in fried foods. In this study, we evaluated a microfluid-assisted flow-blurring spray against conventional application by dipping/spraying, focusing on the coating efficiency and preliminary implications for sustainable process. This study combines benchtop experiments with a near-nozzle numerical analysis where the gas–liquid interface and primary breakup are modeled using the Volume of Fluid (VOF) approach implemented in OpenFOAM, configured for a flow-blurring geometry to generate whey protein isolate (WPI) coatings. Viscosity, density, solid content, and contact angle were validated experimentally and used in the simulation setup. An image-based droplet pipeline quantified spray characteristics, yielding a volumetric median diameter D₅₀ = 83.69 µm and confirming process uniformity. Contact angles showed marked substrate dependence: hydrophilic surfaces, 68°–85°; hydrophobic surfaces, 95°–110°. For turkey sausages, sessile-drop contact angles were not determinable (N.D.) due to wicking/roughness; wettability was therefore assessed on smooth surrogates and via performance metrics. Fit-for-purpose simulation procedures are outlined. Microfluidic application (WPI-McF) lowered oil uptake versus uncoated controls. Together, robust modeling, targeted image analytics, and high-precision microfluidics enable rational tuning of coating microstructure and barrier performance, offering a scalable pathway to reduce lipid content and enhance fried food quality. Full article

Flexible polyurethane foam (FPUF) is widely used in buffer protection, biomedical, and wearable fields due to its light weight, high resilience, and adjustable mechanical properties. However, the traditional water foaming system is often accompanied by bottleneck problems such as cyclic fatigue attenuation, insufficient thermal stability, and surface hydrophilicity while achieving low density. In this study, a dense Si-O-Si cross-linked layer was in situ constructed on the surface of the foam by systematically regulating the water content of the foaming agent (1.5~2.5 wt%) and coupling with methyltrimethoxysilane (MTMS) chemical vapor deposition. Experiments show that the foam foamed with 2 wt% water content still maintains 0.0466 MPa compressive strength and 0.0532 MPa compressive modulus (modulus loss is only 16.6%) after 500 cycles of compression at 90% strain after MTMS deposition. MTMS modification drives the surface wettability to change from hydrophilic (70.4°) to hydrophobic (128.7°), and significantly improves thermal stability (the carbon residue rate at 800 °C increased to 25.5%, an increase of 59.4%). This study not only improves the resilience, but also endows the FPUF surface with hydrophobicity and thermal protection ability, which provides the feasibility for its wide application. Full article

This study develops an incompressible two-phase flow solver based on the open-source OpenFOAM platform, employing the volume-of-fluid (VOF) method to track the gas–liquid interface and utilizing the MULES algorithm to suppress numerical diffusion. This study provides a comprehensive investigation of the spreading dynamics of droplet pairs near walls, along with the presentation of a corresponding mathematical model. The numerical model is validated through a two-dimensional axisymmetric computational domain, demonstrating grid independence and confirming its reliability by comparing simulation results with experimental data in predicting drConfirmedoplet collision, spreading, and deformation dynamics. The study particularly investigates the influence of surface wettability on droplet impact dynamics, revealing that increased contact angle enhances droplet retraction height, leading to complete rebound on superhydrophobic surfaces. Finally, a mathematical model is presented to describe the relationship between spreading length, contact angle, and Weber number, and the study proves its accuracy. Analysis under logarithmic coordinates reveals that the contact angle exerts a significant influence on spreading length, while a constant contact angle condition yields a slight monotonic increase in spreading length with the Weber number. These findings provide an effective numerical and mathematical tool for analyzing the spreading dynamics of droplet pairs. Full article

Although extensive studies have been conducted on the component ratios and performance of fire extinguishing foams, most research has not explored the coupling relationship between foam wettability and adhesion. Therefore, this study aims to develop an efficient foam extinguishing agent for solid fires by focusing on both wettability and adhesion. First, the influence of chemical functional groups on foam wettability and adhesion was elucidated, and the contributions of individual components to foam properties were experimentally investigated. Second, adhesion and wettability tests revealed a negative correlation between these two properties, consistent with variations in foam solution viscosity and wetting time. Third, a novel adhesion evaluation method was proposed, defined as the time required for foam to flow a fixed distance on inclined wooden surfaces; longer flow times indicated stronger adhesion. Fourth, foaming and fire suppression experiments confirmed the practical performance of the optimized formulations. A composition containing 8 wt% Polyoxyethylene ether and 5 wt% Sulfobetaine yielded a wetting-type foam suitable for rapid cooling, whereas 8 wt% Polyoxyethylene ether combined with 9 wt% Sulfobetaine produced an adhesive-type foam capable of persistent attachment to combustibles. Microscopic observations further demonstrated that foams with superior extinguishing performance developed dense lamellae. Full article

The use of advanced wound dressings can significantly support the skin healing process by maintaining optimal conditions for tissue regeneration. In this study, foam-like dressings composed of agarose and chitosan, enriched with vitamin C, were developed using a simple and cost-effective freeze-drying method. Three types of chitosan with varying molecular weights (low, medium, high) were used to investigate their impact on the biological, physicochemical, and mechanical properties of the resulting foams. All fabricated biomaterials were biocompatible, non-toxic, and did not promote cell adhesion to their surfaces. The foams exhibited highly porous, hydrophilic microstructures with excellent fluid absorption capacity (~20 mL/g) and sustained vitamin C release over the first 24 h. Chitosan molecular weight had no significant effect on biological properties, but influenced samples’ wettability and mechanical parameters. The hydrophilic character of samples was observed in all tested biomaterials, with the strongest enhancement of hydrophilicity noted for the low molecular weight variant. The highest tensile strength was observed in samples prepared with medium molecular weight chitosan. The results indicate that among the analyzed variants, agarose-chitosan foam biomaterials containing medium molecular weight chitosan exhibited the most favorable properties, making them the most promising candidates for the treatment of wounds with excessive exudate. Full article

To enhance the fire suppression performance of Class A foam, this study identifies sodium dodecyl sulfate (SDS) as the primary foaming agent and develops a high-efficiency foam system comprising primary and auxiliary foaming agents, wetting agents, and foam stabilizers. It interprets these macroscopic findings at the molecular level through molecular dynamics simulations. Sixteen formulations were designed using orthogonal experiments and evaluated in terms of surface tension, viscosity, wetting performance, and foam expansion ratio. The results demonstrated that the formulated systems exhibited superior foaming characteristics compared to conventional aqueous film-forming foam (AFFF), while other physicochemical properties were inferior. Two high-performing foam systems were further investigated using molecular dynamics simulations. Analysis of the spatial concentration distributions, diffusion coefficients, and the hydrogen-bonding networks of water molecules revealed 14.3% and 14.2% increases in the peak values of the radial distribution function (RDF) for the two systems modified with auxiliary foaming agents, respectively. The auxiliary foaming agents exhibited synergistic effects with SDS, enhancing its water activation capability. The incorporation of wetting agents reduced the water diffusion coefficients by 4.7% and 21.9%, indicating that sodium bis(2-ethylhexyl) succinate sulphonate (T) interferes less with the primary foaming agent than alcohol ethoxylate (AEO). The selected formulations also demonstrated 4.4% and 3.5% reductions in water hydrogen bonding compared to SDS-only solutions, indicating decreased molecular cohesion and improved water activation. By integrating physicochemical evaluation with molecular simulation, the optimized formulation was determined to be SDS (primary foaming agent), sodium fatty alcohol ether sulfate (auxiliary foaming agent), alcohol ethoxylate (wetting agent), lauryl hydroxysultaine (foam stabilizer), and ethylene glycol butyl ether (cosolvent). Full article

In this study, canola oil was used as a natural enriched source of C18 fatty acids and coconut oil as a natural enriched source of C12 fatty acids. The study synthesized five potassium carboxylate (RCOO⁻K⁺) liquid soaps via saponification of coconut–canola oil blends (100:0, 75:25, 50:50, 25:75, 0:100) using a novel in situ dissolution method with controlled KOH addition to prevent solid paste formation. The water demand required to dissolve RCOO⁻K⁺ and mitigate soap crystallization was determined, increasing from 1.76 to 5.18 g H₂O/g oil as canola oil content rose, with soap concentration decreasing from 55.1% (100:0) to 18.5% (0:100). Reaction kinetics revealed faster KOH depletion in coconut oil-rich blends (100:0, 75:25, 50:50; 2 h) compared to canola oil-rich blends (25:75, 0:100; 8 h). Key soap properties, including foam stability, detergency, wettability, viscosity, and thermal behavior, were assessed. The 50:50 blend exhibited the highest foam stability due to the synergistic effects of medium-chain saturated (e.g., laurates) and long-chain unsaturated (e.g., oleates) RCOO⁻K⁺. The short, saturated chains promoted rapid foam formation, while the longer, unsaturated chains enhanced foam film stability. RCOO⁻K⁺ detergency on hair tresses with artificial sebum ranged from 16.9% to 29.7% and was relatively higher compared to sodium lauryl sulfate, sodium laureth sulfate, cocamidopropyl betaine, and sodium cocoyl glutamate (6.1–13.2%) but lower compared to sodium isethionates (34.2%). RCOO⁻K⁺ wettability on cotton textiles improved with higher coconut oil content. RCOO⁻K⁺ contact angles on artificial sebum surface (6.1–13.7°) demonstrated excellent wettability, effectively penetrating and emulsifying hydrophobic residues. Viscosity ranged from 13–45 mPa·s with Newtonian Flow-type behavior. No crystals were observed in the soaps when cooled in the range of 60 to −30 °C. These results demonstrate RCOO⁻K⁺ soaps as tunable, sustainable liquid soaps with performance optimized by adjusting the oil blend ratios. Full article