Search Results (2,024)

Proton exchange membrane fuel cells (PEMFC) are recognized as promising next-generation energy technology. Yet, their performance is critically limited by inefficient gas transport and water management in conventional flow channels. Current rectangular gas channels (GC) restrict reactive gas penetration into the gas diffusion layer (GDL) due to insufficient longitudinal convection. At the same time, the complex multiphase interactions at the mesoscale pose challenges for numerical modeling. To address these limitations, this study proposes a novel cathode channel design featuring laterally contracted fin-shaped barrier blocks and develops a mesoscopic multiphase coupled transport model using the lattice Boltzmann method combined with the volume-of-fluid approach (LBM-VOF). Through systematic investigation of multiphase flow interactions across channel geometries and GDL surface wettability effects, we demonstrate that the optimized barrier structure induces bidirectional forced convection, enhancing oxygen transport compared to linear channels. Compared with the traditional straight channel, the optimized composite channel achieves a 60.9% increase in average droplet transport velocity and a 56.9% longer droplet displacement distance, while reducing the GDL surface water saturation by 24.8% under the same inlet conditions. These findings provide critical insights into channel structure optimization for high-efficiency PEMFC, offering a validated numerical framework for multiphysics-coupled fuel cell simulations. Full article

Electrospinning is a widely used technique for fabricating nanomaterials with tailored morphology and functional properties. This study investigates how two fundamental process parameters—applied voltage and needle tip-to-collector distance—affect the spatial geometry and deposited mass of electrospun nanofiber mats in a top-down vertical electrospinning setup using a 10% (w/v) PVA solution prepared in deionized water. To support this hypothesis, both experimental measurements and 3D geometric modeling were performed to evaluate the area, perimeter, and deposited mass under different parameter combinations. Digital image analysis and cross-sectional reconstruction were applied to model nanofiber deposition. Regression and ANOVA analyses reveal that the tip-to-collector distance has a statistically significant impact on both area and perimeter of the electrospun nanofiber mat, while the applied voltage in the tested range (15–20 kV) has no significant effect. Interestingly, the total deposited mass shows no clear dependence on either parameter, likely due to startup irregularities or solution droplets. Full article

Droplet impact on porous mesh surfaces is a common phenomenon in fields such as thermal management systems, biomedical manufacturing, and precision agriculture. As a substrate with microstructures, the mesh surface allows liquid penetration upon droplet impact. The resulting loss of liquid mass significantly alters the impact dynamics of the residual droplet on the surface. This study experimentally compares the behavior of water droplets impacting superhydrophobic mesh surfaces with different pore sizes against that on smooth surfaces. It focuses on analyzing how liquid penetration affects parameters such as spreading time ($t_s$), maximum spreading factor (${\beta }_{max}$), contact time ($t_c$), and droplet height ($h$). The results show that the substantial liquid loss induced by large-pore meshes directly leads to a marked decrease in spreading time and maximum spreading factor. Furthermore, the “pancake bouncing” phenomenon observed on the superhydrophobic mesh surfaces significantly shortens the contact time, providing a new perspective for minimizing the contact duration between droplets and solid surfaces. By establishing the correlation between pore size and droplet impact behavior, this study provides key structural design guidelines for applications such as advanced printing systems and efficient pesticide spraying, thereby achieving the goal of proactively regulating liquid dynamics through surface microstructure. Full article

This work evaluated the effect of coffee oil epoxide (COE), produced from coffee waste, on thermal, mechanical, barrier, and exudation resistance properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/natural rubber (PHBV/NR) blends. Building upon previously published 0.3% COE results, this study examined 0.4% and 0.75% concentrations to optimize performance. Thermal analysis revealed that COE incorporation significantly enhanced chain mobility, with glass transition temperature depressions of 6.1 °C and 7.4 °C for 0.4% and 0.75% COE formulations, respectively, compared to unplasticized PHBV/NR blends. Crystallinity decreased from 54.5% (PHBV/NR) to 52.6% and 51.9% with increasing plasticizer concentration, while melting temperatures decreased by 3.9% and 4.9%, confirming improved polymer chain mobility. Mechanical properties demonstrated COE’s plasticizing effectiveness, with tensile strength decreasing by 13.3% (0.4% COE) and 16.2% (0.75% COE) compared to PHBV/NR blends. Young’s modulus similarly decreased by 21.0% and 24.0%, while elongation at break improved slightly with increasing COE content. Barrier properties improved substantially across all concentrations: water vapor transmission rates decreased from 4.05 g/m²·h (PHBV/NR) to 1.55 g/m²·h (0.3% COE) and 0.67 g/m²·h for 0.4% and 0.75% COE, attributed to COE’s hydrophobic nature. SEM morphological analysis confirmed improved phase compatibility at 0.40% COE, with reduced rubber droplet size and homogeneous surface morphology. Exudation testing revealed excellent retention (0.21–0.53 wt% loss over 63 days). Results indicate 0.40% COE as optimal, achieving superior barrier properties while maintaining mechanical performance for sustainable packaging applications. Full article

This study primarily simulates the flashover phenomenon between the metal fittings (rods) and the skirt surface (plates) of insulators when water droplets traverse between them under heavy rain conditions. High-speed cameras recorded droplet deformation and breakdown processes, while electric field simulation software modeled the air gap’s electric field distribution. The effects of air gap length, axial position of the water droplet, droplet conductivity, droplet diameter, and voltage polarity on the DC breakdown voltage were analyzed. Results indicate that a larger air gap leads to a greater reduction in droplet breakdown voltage and lower electric field uniformity. The breakdown voltage is essentially independent of changes in the axial position of the droplet and the droplet’s conductivity. The breakdown voltage exhibits no significant correlation with droplet diameter. Droplets rarely break down when voltage is applied to the electrodes, indicating that flashover at the low-voltage end of insulators during rainfall occurs infrequently. This research holds significant importance for elucidating the flashover mechanisms of water droplets at both ends (high-voltage and low-voltage) of the insulators and for guiding the design of external insulation for power equipment. Full article

This study presents an eccentric pipe separator (EPS) designed according to the shallow pool principle and Stokes’ law as a compact alternative to conventional gravitational tank separators for offshore platforms. To investigate the internal oil-water flow characteristics and separation performance of the EPS, both field experiments with crude oil on an offshore platform and computational fluid dynamics (CFD) simulations were conducted, guided by dimensional analysis. Crude oil volume fractions were measured using a Coriolis mass flow meter and the fluorescence method. The CFD analysis employed an Eulerian multiphase model coupled with the renormalization group (RNG) k-ε turbulence model, validated against experimental data. Under the operating conditions examined, the separated water contained less than 50 mg/L of oil, while the separated crude oil achieved a purity of 98%, corresponding to a separation efficiency of 97%. The split ratios between the oil and upper outlets were found to strongly influence the phase distribution, velocity field, and pressure distribution within the EPS. Higher split ratios caused crude oil to accumulate in the upper core region and annulus. Maximum separation efficiency occurred when the combined split ratio of the upper and oil outlets matched the inlet oil volume fraction. Excessively high split ratios led to excessive water entrainment in the separated oil, whereas excessively low ratios resulted in excessive oil entrainment in the separated water. Crude oil density and inlet velocity exhibited an inverse relationship with separation efficiency; as these parameters increased, reduced droplet settling diminished optimal efficiency. In contrast, crude oil viscosity showed a positive correlation with the pressure drop between the inlet and oil outlet. Overall, the EPS demonstrates a viable, space-efficient alternative for oil-water separation in offshore oil production. Full article

Curcumin is a polyphenolic compound isolated from Curcuma longa, which is widely recognized for its therapeutic properties: particularly its strong anti-inflammatory and antioxidant activities. However, its practical incorporation into functional foods, especially aqueous dairy beverages, is severely hindered by its extremely low water solubility, poor chemical stability (notably at the near-neutral pH of milk), and very limited oral bioavailability. This review provides a critical synthesis of the literature published in the last two decades, with a focus on the development and application of food-grade oil-in-water (O/W) nanoemulsions to advanced colloidal delivery systems. It covers the fundamental principles of nanoemulsion formulation, including the selection of the oil phase, surfactants, and stabilizers, as well as both high-energy and low-energy fabrication techniques. It further examines the integration of these nano-delivery systems into dairy matrices (milk, yogurt, cheese), highlighting key interactions between nanoemulsion droplets and native dairy constituents such as casein micelles and whey proteins. Critically, findings indicate that nanoencapsulation not only enhances curcumin’s solubility but also protects it from chemical degradation during industrial processes, including pasteurization and sterilization. Moreover, the dairy matrix structure plays a key role in modulating curcumin bioaccessibility, with fortified products frequently exhibiting enhanced stability, shelf life, and sensory attributes. Finally, key technological challenges addressed the heterogeneous global regulatory landscape surrounding biopolymers and future trends: most notably, the growing shift toward “clean-label” biopolymer-based delivery systems. Full article

Soybean wax is a sustainable alternative to synthetic polymeric coatings in packaging due to its renewable, environmentally benign, and hydrophobic properties. In order to be effectively applied, however, soybean wax must be emulsified in water. The present work compares two stabilization approaches for soybean wax emulsions: a conventional surfactant-based emulsion (SE) using a mixture of nonionic surfactants (Span-80 and Tween-80), and a Pickering emulsion (PE) using cellulose nanocrystals combined with sodium alginate (CNC-SA) as an anionic stabilizer. The SE produced stable emulsions at 6 wt% Span-80/Tween-80 (at a HLB_mix value of 10) with a mean droplet size of 449 nm but limited storage stability (approximately 7 days under ambient conditions), while the PE achieved superior stability (approximately 1 month) at 1 wt% CNC-SA with a mean droplet size of 740 nm. The stabilized SE and PE were subsequently applied as coatings on three different types of paper substrates: northern bleached kraft (NBK) paper, copy paper, and cellulose nanofiber (CNF)-coated NBK paper. When applied to northern bleached kraft (NBK) paper, the SE coatings provided minimal improvements in barrier performance. The Cobb 60 value decreased slightly from 125 g/m² (control-no coating) to 86 g/m², indicating a negligible water barrier with immediate water absorption upon contact. In contrast, the Cobb 60 value of the PE-coated NBK paper decreased markedly from 125 g/m² to 39 g/m², confirming that the PE coating substantially enhances water resistance. The SE coating displayed a significant loss of water contact angle (WCA) from 85° to 0° within 20 s, showing limited water holdout capacity, whereas PE-coated NBK paper demonstrated strong water holdout, with the WCA decreasing only from 94° to 85° over 5 min. The SE coating achieved only a 14% reduction in water vapor transmission rate (WVTR), while the PE coating provided a greater reduction of 30%. In terms of oil resistance, both emulsion systems significantly enhanced the kit rating of the papers tested, e.g., from kit number 0 to 6–9 (paper dependent). The SE coating, however, experienced a substantial reduction in barrier integrity after folding, while the PE coating largely retained its oil barrier properties. Furthermore, the SE coating reduced the tensile strength of NBK paper by 41%, whereas the PE coating reduced it by only 7%. Overall, the comparative findings indicate that although the SE generated a smaller mean particle size, it offered minimal improvement in the water and oil barrier performance of paper and had a limited storage life. In contrast, the PE generated a larger mean particle size, but provided substantially greater water and oil resistance, and enhanced mechanical strength retention. In addition, the PE displayed an effective storage life of at least one month. The Pickering emulsion, formulated with all biologically derived components, therefore represents a viable, sustainable, bio-based alternative to synthetic polymeric coatings for packaging applications. Full article

Water scarcity constitutes a major global challenge. Biomimetic water collection materials, which mimic the efficient water capture and transport mechanisms, offer a crucial approach to addressing the water crisis. This review summarizes the research progress on biomimetic water collection materials, focusing on biological prototypes, operational mechanisms, and core aspects of biomimetic design. Typical water-collecting biological surfaces in nature exhibit distinctive structure–function synergy: spider silk achieves directional droplet transport via periodic spindle-knot structures, utilizing Laplace pressure difference and surface energy gradient; the desert beetle’s back features hydrophilic microstructures and a hydrophobic waxy coating, forming a fog-water collection system based on heterogeneous wettability; cactus spines enhance droplet transport efficiency through the synergy of gradient grooves and barbs; and shorebird beaks enable rapid water convergence via liquid bridge effects. These biological prototypes provide vital inspiration for the design of biomimetic water collection materials. Drawing on biological mechanisms, researchers have developed diverse biomimetic water collection materials. This review offers a theoretical reference for their structural design and performance enhancement, highlighting bio-inspiration’s core value in high-efficiency water collection material development. Additionally, this paper discusses challenges and opportunities of these materials, providing insights for advancing the engineering application of next-generation high-efficiency biomimetic water collection materials. Full article

We demonstrate the enhancement of antibacterial and cytocompatibility characteristics of femtosecond laser-treated pure titanium and Ti-6Al-4V titanium alloy samples suitable for orthopedic implant applications. We controlled the wettability of the titanium samples by tailoring the surface geometry using a femtosecond laser. To increase the hydrophobicity, laser-assisted micro-grids patterning was performed on the titanium samples, where we achieved a highest contact angle of 144.6° for a 1 µL de-ionized water droplet. In contrast, the hydrophobic Ti-6Al-4V titanium alloy surfaces were converted to hydrophilic surfaces by fabricating periodic micro-gratings on the samples’ surface, where a lowest contact angle of 19.84° was achieved. Furthermore, we assessed the biocompatibility of the micro-patterned titanium samples by investigating the antibacterial activity against Staphylococcus Aureus bacteria. Moreover, the cytocompatibility of the micro-patterned titanium samples was examined using NCTC Clone 929 (L-929) mouse fibroblasts. The laser-treated titanium samples exhibited enhanced antibacterial performance while maintaining excellent cell compatibility. The experimental results confirmed excellent correlation with the wettability of the laser-patterned samples and their antibacterial characteristics and cytocompatibility. Overall, the findings highlight femtosecond laser surface structuring as a highly effective strategy to simultaneously improve antibacterial behavior and the biocompatibility of implant materials, offering a promising way for the advanced functionalization of orthopedic implants. Full article

Filtration of emulsions is an important operation in multiple processes of chemical, environmental, and petroleum engineering. The primary concern of the present study is cleaning of water produced from a petroleum reservoir. The produced water is filtered from the oil droplets before being dumped into the sea or reinjected into the reservoir. Efficiency of filtration is determined, in particular, by the droplet size distribution and interfacial properties. We have developed a new population balance model of emulsion filtration, based on the Boltzmann–Smoluchowski approach. The model accounts for the droplet size distribution, as well as for the different mechanisms of the droplet capture: attachment to the surface and straining in the pore constrictions. The model can not only be applied to filtering of the produced water, but also to more general emulsion processing. It is capable of reproducing experimental data on the droplet production history and dynamic permeability decline. The sensitivity study indicates low sensitivity of the permeability decline curves to the model parameters. The production histories or other kinds of experimental data are necessary to discriminate between the different parametrizations of the model. Full article

This study reports the effect of pH (2, 7, 10) and heat treatment (80 °C for 30 min) on the oil–water (o/w) interfacial behavior of hemp seed protein isolate (HPI) aqueous dispersions. The physicochemical, interfacial adsorption, rheology, and emulsifying properties of protein dispersions were evaluated. HPI dispersions at pH 10 exhibited the highest water solubility (60%), the greatest net charge (−27 mV), and the lowest hydrophobicity (~5 a.u.), promoting o/w interfacial pressure (π) and interfacial viscoelasticity. Strong interfacial viscoelastic protein layers (E^* = 25 mN/m) were also observed under acidic conditions (pH 2), where proteins exhibited high solubility (40%), a high positive net charge (21 mV), and increased hydrophobicity (46 a.u.). HPI dispersions in their neutral state (pH 7) were not able to form stable o/w emulsions due to their poor physicochemical properties such as low solubility (18%), low surface charge (−18 mV), and hydrophobicity (~5 a.u.). Heat treatment significantly increased the charge and hydrophobicity of both neutral and alkaline proteins (~30 mV and ~10 a.u., respectively), increasing their particle size distribution and ultimately reducing their interfacial protein layer elasticity (E^* = 20 and 13 nM/m, respectively). While particles at acidic conditions showed high thermal resistance, heat treatment improved the emulsifying stability in alkaline conditions while further reducing it in the neutral state. Overall, HPI dispersions demonstrated the ability to form stable emulsions at both alkaline and acid pHs, with those formed at pH 2 exhibiting a lower droplet size and superior stability. Full article

Tilapia lake virus (TiLV) is a highly virulent pathogen that has caused substantial mortality in tilapia farms, particularly those with open-water systems. However, TiLV can also emerge and persist in closed environments, such as recirculating aquaculture systems (RAS), where environmental accumulation and repeated exposure may intensify infection and sustain outbreaks. In this case study, we conducted three field experiments to better understand TiLV dynamics among Nile tilapia in RAS. In experiment I, we quantified the TiLV levels in the fish, water, and sediment to compare outbreak and no-outbreak conditions and found that the TiLV concentrations in liver samples and the water were significantly higher in the outbreak ponds and positively correlated with increased fish mortality. In experiment II, we used a side-by-side field trial to evaluate the protective efficacy of a TiLV vaccine and its effects on the viral loads in the fish and aquatic environment during outbreaks. The vaccinated fish showed substantially lower cumulative mortality (16.7%) than the unvaccinated controls (37.7%), with a relative percent survival of 55.6%. Additionally, the TiLV concentrations in the pond water of the vaccinated group were significantly lower. In experiment III, we compared the TiLV patterns between RAS and non-RAS operations to determine how water recirculation influences viral accumulation and outbreak severity. The results revealed limited viral accumulation and shorter disease outbreak duration in the non-RAS. Overall, our findings showed that the TiLV levels in the rearing water were closely linked with disease severity in the RAS-based tilapia hatcheries. Continuous water recirculation allowed the virus to build up in the system, which led to more prolonged outbreaks, while the non-RAS conditions with regular water discharge showed lower viral loads and faster recovery. The vaccinated fish had better survival rates and released less virus into the water, which helped reduce infection pressure across the ponds. Together, these results suggest that combining vaccination with good water management and molecular monitoring can provide a practical, noninvasive way to detect and control TiLV outbreaks in intensive farming systems. Full article

This study investigated the effects of pH (3, 5, 7, 9, 11) on the structure–activity relationship and stability mechanism of Pickering emulsions stabilized by the gorgon euryale starch–quinoa protein complex. Analyses were performed using reverse compression test, rheology, thermal stability assessment, atomic force microscopy (AFM), and low-field nuclear magnetic resonance (LF-NMR) measurements. Reverse compression test showed that the emulsion at pH 3 exhibited the highest hardness and consistency, but the weakest cohesiveness. Rheological measurements revealed that all emulsions displayed shear-thinning behavior, the emulsion at pH 3 had the highest shear stress and apparent viscosity, while that at pH 11 showed the lowest viscosity due to the destruction of macromolecular structures. Thermal stability assessment indicated that the emulsion at pH 3 did not undergo significant stratification even at 60 °C, whereas the stability of emulsions decreased between pH 5–9. Microscopic analyses (optical microscopy, AFM, and LF-NMR) further confirmed that the emulsion at pH 3 had fine, uniform droplets, strong water-binding capacity, and an interfacial film with a “dense protrusion” structure. This study provides a basis for the environmental adaptability design of functional emulsions and contributes to the high-value utilization of gorgon euryale and quinoa resources. Full article

Existing experimental findings often prove insufficient for guiding the design of water mist fire extinguishing systems, primarily due to the multitude of interacting factors that influence extinguishing performance. This paper systematically synthesizes these factors and delineates their logical interrelationships based on the extinguishing mechanisms of water mist and a review of the existing literature. The analysis focuses on direct influencing factors by modeling the motion, heat transfer and mass transfer of water mist within the flame zone. The results indicate that, when the influence of the fire flame is negligible, the required velocity and droplet diameter of water mist entering the zone can be determined based on the flame temperature differential and flame height. When plume effects are significant, water mist predominantly enters the flame zone from the top and periphery. Under such conditions, determining the mist velocity and diameter should aim to maximize the total heat absorption power of droplets entering via these two pathways. This study provides a theoretical foundation for the design of a water mist fire extinguishing system. Full article