Continuous Phase Research Articles

Formation of Nonspherical Cellulose Acetate Microparticles under Microflow.

Nonspherical particles have gained significant interest owing to their unique shapes and large specific surface areas, making them suitable for a wide range of applications, such as drug delivery, catalysis, and adsorption. However, conventional methods for preparing nonspherical particles face certain limitations. In this study, we propose a simple method for fabricating nonspherical cellulose acetate (CA) microparticles using a microfluidic device in which droplets undergo rapid diffusion in a continuous aqueous phase. The influence of variations in the flow rate ratio and continuous phase composition on the dimensionless Péclet number (Pe) within the droplet and shape of the resultant particles is investigated. Pe is critical, because it indicates the balance between polymer diffusion and droplet shrinkage dynamics. Our findings reveal that increasing the flow rate ratio and reducing the methyl acetate concentration in the continuous phase lead to faster droplet shrinkage and an increased Pe. A high Pe (>100) suggests that the reduction of the droplet interface predominates over polymer diffusion, resulting in the formation of a viscous layer near the droplet surface, which subsequently leads to nonspherical particle shapes (such as bowl-like or biconcave structures). In situ time-lapse observations of droplets from the top and side of a microchannel reveal that the formation of a viscous layer near the droplet surface and the deformation of the droplet, influenced by the z-axis location of the droplets during particle formation, ultimately determine the final particle shape. Based on these observations, a linear correlation between the initial conditions, i.e., the Pe and z-axis location at which the viscous layer formed, is established, enabling the prediction of the particle structure. In summary, the present study enhances the understanding of shape control in microfluidic particle formation and offers a novel guideline for the fabrication of spherical and nonspherical particles.

Characterization of interactions in battery slurry via MD simulation: Influence on miscibility, morphology, and dispersion with varying ACN content in HNBR.

This paper investigates the phase behaviors, morphology changes, and degree of dispersion of a multi-component cathode battery slurry system. The slurry comprises polyvinylidene fluoride (PVDF) as the binder, hydrogenated nitrile butadiene rubber (HNBR) as the dispersant with varying acrylonitrile (ACN) content, N-methyl-2-pyrrolidone (NMP) as the solvent, and carbon nanotubes/graphene (CNTs/GRA) as the conductive agent. Several analytical methods, including visualized imaging, solubility parameters, radial distribution function (RDF) analysis, β phase PVDF analysis, near-atom analysis, and potential of mean force (PMF) analysis, were employed to compare the slurry's characteristics. The results indicate that an increase in ACN content in HNBR improves the miscibility between HNBR and PVDF, while HNBR with low ACN content results in a crystalline structure and phase separation of HNBR and PVDF. Conversely, increasing the ACN content in HNBR has a negative impact, making it a poorer dispersant itself. These findings provide essential insights into effectively regulating the phase behavior, miscibility, and dispersion ability of multi-component slurry systems, thereby enhancing the performance of lithium-ion batteries.

Development of complex wastewater treatment of galvanizing lines

The prospective of increasing of environmental safety level for industrial enterprises as a result of the implementation of new complex wastewater treatment technology are considered. An analysis of literary sources was carried out regarding the effectiveness of the existing methods of wastewater treatment that contain compounds of heavy metals. The efficiency of iron ion extraction was investigated by processing of steel pickling solutions using the ferritization with various activation methods of the reaction mixture. X-ray phase analysis of the obtained ferritization sediments confirmed the presence of highly dispersed ferromagnetic phases of iron oxides and oxyhydroxides. The sorption capacity of magnetite sediment obtained by ferritization on the efficiency of zinc ion extraction from the wastewater of the galvanic line was studied. The influence of pH value and ultrasound on sorption treatment of washing wastewater by magnetite sediment was determined. When using ultrasound for sorbent treatment and raising the pH to 10, the residual concentration of zinc ions in the washing wastewater decreases to 0.31 mg/dm3, the degree of purification is 98.9%. Such water meets the standards for its use in the operations of washing parts at electroplating facilities or discharge into the city's central sewage system. The prospects for the utilization of spent sorbents in powder paint and varnish materials as a result of the inclusion in their composition of ferritization products obtained from electroplating waste are considered. The use of ferromagnetic waste from sorption treatment improves the corrosion resistance of the resulting coatings compared to traditional ones. The implementation of research results at enterprises will prevent environmental pollution by toxic substances, change outdated production technologies and obtain from production waste materials for corrosion protection of metal construction.

Fabrication and Characterization of Supported Porous Au Nanoparticles

Porous plasmonic nanoparticles offer unique advantages for sensing and catalysis due to their high surface-to-volume ratio and localized electromagnetic field enhancements at nanoscale pores, or “hotspots.” However, current fabrication techniques, which are based on colloidal synthesis, face challenges in achieving precise control over particle size, shape, and porosity. Here, we present a robust nanofabrication method to produce supported arrays of porous Au nanoparticles with excellent dimensional and compositional control. By combining lithographically patterned AuAg alloy nanoparticles and selective dealloying via nitric acid, we achieve particle porosity without compromising particle morphology. Specifically, the method allows fabrication of supported porous nanoparticles with tunable dimension and porosity. Our approach demonstrates precise control of nanoparticle porosity by varying the initial Ag content in the alloy. Optical characterization reveals a blueshift in the extinction peak with increasing porosity, attributed to the reduced effective refractive index from intraparticle voids. Notably, a tunable shift of up to 100 nm in the plasmonic peak is observed, demonstrating the potential for fine-tuning optical properties. This study highlights the versatility of the proposed method in fabricating well-defined porous plasmonic nanoparticles and their ability to modulate optical properties through porosity control. These findings not only expand the toolkit for designing advanced plasmonic materials but also open pathways for applications in plasmon-mediated sensing, catalysis, and photonic devices.

The Influence of Vortex Flow in the Dispersed Phase on Droplet Formation Dynamics

Abstract This work explores the characteristics of a two-phase system&s dispersed phase flow that interacts inside the microfluidic channel at the junction. Direct visualization and µ-particle image velocimetry measurements are performed on the interaction of two immiscible fluids in different stepped flow-focusing (S.F.F.) channels for droplet formation. The capillary instabilities produce the counter-rotating vortex flow in dispersed phase fluid at the interface, which plays a significant role in droplet formation. The vortex flow has been analyzed using various data processing techniques. The effect of flow rate and step channel dimensions on the evolution of the vortices generated during droplet thread propagation is studied. The strength of the vortex and momentum flux led to the development of more bulging shapes in the droplet thread. Also, this study exhibits transient flow characteristics during the detachment stage and contributes to understanding its influences on mass transfer at the micro-level dimensions.

Experimental studies of dispersed phase axial dispersion in pulsed sieve plate columns

ABSTRACT Residence time distribution of the dispersed phase in a 40 mm diameter pulsed sieve plate column is measured with a pulse tracer injection technique and the axial dispersion coefficient E D, calculated. Water is chosen as the dispersed phase and n-dodecane as the continuous phase. Dependence of E D on phase velocities, pulse velocity Af and geometrical parameters – perforation diameter d, fractional-free area of the sieve plate, and plate spacing is investigated. The ED vs Af plots show either a change in slope or a local maximum at the transition from mixer-settler to emulsion regime. The effect of perforation diameter d on E D is mediated by the pulse velocity Af. At low Af, E D increases with d, but for Af > 11 mm/s, E D is insensitive to d. E D is found to have inverse relationships with the fractional free area and plate spacing. However, the decrease in E D with S depends on the pulse velocity Af and the superficial velocity of the dispersed phase. Experimental results are fitted to various correlations for E D available in the published literature, with the best fit as quantified through relative error is found for the correlation proposed by Srinikethan et al.

Hexagonal Boron Nitride as a Two-Dimensional Surfactant: Low-Density Flame-Resistant Composites Based on Boron Nitride Exfoliated by an Interface Trapping Technique.

Hexagonal boron nitride (hBN) is a two-dimensional material isoelectric to graphene. It has a hexagonal structure with alternating boron and nitrogen atoms and is electrically insulating, thermally conductive, and chemically inert. However, like graphene, its use as a functional nanofiller requires exfoliation. Here, we present a method for exfoliating and dispersing hexagonal boron nitride (hBN) sheets within a polymer matrix. This is achieved by a solvent interface trapping method (SITM), where hBN exfoliates and spreads at a high-energy oil/water interface, separating the two phases and lowering the system's free energy. hBN thus acts as a surfactant, allowing us to form stable water-in-oil emulsions stabilized by films of overlapping hBN sheets. Polymerizing the continuous oil phase results in polymerized high internal phase emulsions (polyHIPE), with the foam cells lined with hBN. In the investigation presented here, we use acoustic spectroscopy, optical and electron microscopy, and image analysis to study the emulsion and polyHIPE formation mechanisms. We find that the amount of hBN used, the flake size of the hBN, the mixing time, the type of initiator used, and the oil-to-water ratio all play a role in the morphology of the final polyHIPE. Lastly, we demonstrate the flame-retardant properties of the hBN polyHIPEs and show that, at 1% loadings, the presence of hBN prevents dripping and relighting of the composites, even when the material is heated to a red glow.

Structural transitions of calcium carbonate by molecular dynamics simulation.

Calcium carbonate (CaCO3) plays a crucial role in the global carbon cycle, and its phase diagram is of significant scientific interest. We used molecular dynamics to investigate selected structural phase transitions of calcium carbonate. Using the Raiteri potential, we explored the structural transitions occurring at the constant pressure of 1bar, with temperatures ranging from 300 to 2500K, and at the constant temperature of 1600K, with pressures ranging from 0 to 13GPa. With increasing temperature, the transitions between calcite, CaCO3-IV, and CaCO3-V were characterized. In the calcite structure, the carbonate ions are ordered in a planar triangular arrangement, alternating with layers of calcium ions. As the temperature increases, the transition from calcite to CaCO3-IV occurs, leading to partial disordering of the carbonate ions. At higher temperatures, CaCO3-IV transforms into CaCO3-V. Through free energy analysis, we classified the latter transition as a continuous phase transition. At a temperature of 2000K, a "disordered CaCO3" structure appears, characterized by low order within the calcium and carbonate sublattices and the free rotation of the carbonate ions. With increasing pressure, two calcium carbonate transformations were observed. At P = 2GPa, the CaCO3-V phase undergoes a phase transition into CaCO3-IV, demonstrating that the model can describe the transition between these two phases as pressure- and temperature-driven. At P = 4.25GPa, CaCO3-IV undergoes a phase transition into the CaCO3-Vb phase. This transition is classified as first-order based on free energy calculations.

Colloidal quantum dots as solution-based nanomaterials for infrared technologies.

This review focuses on the recent progress of wet-chemistry-based synthesis methods for infrared (IR) colloidal quantum dots (CQD), semiconductor nanocrystals with a narrow energy bandgap that absorbs and/or emits infrared photos covering from 0.7 to 25 micrometers. The sections of the review are colloidal synthesis, precursor reactivity, cation exchange, doping and de-doping, surface passivation and ligand exchange, intraband transitions, quenching and purification, and future directions. The colloidal synthesis section is organized based on precursors employed: toxic substances such as mercury- and lead-based metals and non-toxic substances such as indium- and silver-based metal precursors. CQDs are prepared by wet-chemical methods that offer advantages such as precise spectral tunability by adjusting particle size or particle composition, easy fabrication and integration of solution-based CQDs (as inks) with complementary metal-oxide-semiconductors, reduced cost of material manufacturing, and good performances of IR CQD-made optoelectronic devices for non-military applications. These advantages may allow facile and materials' cost-reduced device fabrications that make CQD-based infrared technologies accessible compared to optoelectronic devices utilizing epitaxially grown semiconductors. However, precursor libraries should be advanced to improve colloidal infrared quantum dot synthesis, enabling CQD-based IR technologies to be available to consumer electronics. As the attention of academia and industry to CQDs continues to proliferate, the progress of precursor chemistry for IR CQDs could be rapid.

Time-dependent wave motion in a running stream due to initial disturbances in Magnetohydrodynamics

Abstract The generation of two-dimensional time-dependent magneto-hydrodynamic surface waves in a flowing stream is investigated in this paper. The waves here arise from some initial disturbances at the free surface of an electrically conducting field-free fluid, which is of finite depth. It is also assumed that a constant magnetic field exists outside the air-water interface. With the help of linearised theory, the present problem is modeled as an initial boundary value problem, and the Laplace-Fourier transform techniques are primarily used to obtain the form of free surface elevation through infinite integrals. These integrals are then interpreted asymptotically for large time t and distance x from the origin, using the method of stationary phase. Dispersion relation, phase, and group velocities are also studied. Numerical results of the asymptotic form of free surface elevation are obtained in a number of figures for different values of current speed, Alfven velocity, and various types of initial disturbances. Graphical representations demonstrate that the presence of a magnetic field has a significant effect on wave motion.

Analysis and optimization of heat transfer performance of multi-stage tower-type direct contact heat exchangers in waste heat recovery

Improving the uniformity of two-phase mixing has been shown to significantly enhance heat transfer efficiency. In this study, A novel multi-stage tower-type heat exchanger is proposed for application in direct contact heat exchange, which improves the uniformity of two-phase mixing and heat transfer efficiency. A heat transfer coefficient based on the harmonic mean method is proposed to evaluate the heat transfer efficiency of complex heat exchanger structures. The results indicate that the multi-stage tower-type direct contact heat exchanger enhances heat transfer performance by 1.67% to 3.49% compared to traditional heat exchangers of equivalent volume across various continuous phase temperatures. Additionally, the heat exchanger is segmented into various sub-sections to measure the harmonic mean volumetric heat transfer coefficient. Under experimental conditions with continuous phase temperatures between 60 °C and 100 °C, the heat transfer coefficients for the multi-stage tower heat exchanger range from 623 to 1945 W/(m3∙K). This study aims to optimize the structure and heat transfer performance of the heat exchanger, which provides a new idea for the evaluation system of complex shaped heat exchangers.

Dynamics analysis of epidemic spreading with individual heterogeneous infection thresholds

In the real world, individuals may become infected with an epidemic after multiple exposures to the corresponding virus. This occurs because each individual possesses certain physical defenses and immune capabilities at the time of exposure to the virus. Repeated exposure to the virus can lead to a decline in immune competence, consequently resulting in epidemic infection. The susceptibility of individuals to an epidemic is heterogeneous. We model this characteristic as the individual heterogeneous infection threshold. Then, we propose an individual logarithmic-like infection threshold function on a single-layer complex network to reflect the heterogeneity of individual susceptibility on infecting the virus and the associated epidemic. Next, we introduce a partition theory based on the edge and logarithmic-like infection threshold function to qualitatively analyze the mechanisms of virus infection and epidemic spreading. Finally, simulation results on Erdő–Rényi (ER) and scale-free (SF) networks indicate that increasing both the epidemic infection initial threshold and outbreak threshold, as well as decreasing the virus and epidemic infection probability, can all effectively suppress epidemic spreading and epidemic infection outbreak. With an increase in the epidemic infection outbreak threshold, the increasing pattern of the final epidemic infection scale transitions from a second-order continuous phase transition to a first-order discontinuous phase transition. Additionally, degree distribution heterogeneity also significantly impacts the outbreak and spread of diseases. These findings provide valuable guidance for the formulation of immunization strategies.

Exploiting the positive effect of REFe2 (RE=rare earth) phase on coercivity in Nd-Ce-Fe-B sintered magnets

The REFe2 phase is inherent in high Ce content Nd-Ce-Fe-B magnets, and how to harness its existence and exert its beneficial effects on magnetic properties is an essential topic in the development of these magnets. In this work, we reveal the positive impact of the REFe2 phase on coercivity enhancement by designing the RE-rich B-lean composition in the Nd-Ce-Fe-B sintered magnet with 30 wt. % Ce replacing Nd. The coercivity in the as-sintered state attains 14.07 kOe and slightly increases to 14.54 kOe upon post-sinter annealing. Phase composition and microstructure analysis indicate that the Fe-storage effect of the REFe2 phase immobilizes a large amount of Fe elements in the triple junctions, resulting in the development of a continuous Fe-lean non-ferromagnetic grain boundary phase with thickness exceeding the exchange length. In addition, the magnetization and demagnetization behaviors were analyzed by the recoil loops to reveal the coercivity mechanisms. This work demonstrates that, in addition to improving wettability, the Fe-storage effect of the REFe2 phase positively influences coercivity.

Mechanisms of Low Temperature Thickening of Different Materials for Deepwater Water-Based Drilling Fluids

During deepwater drilling, the low mudline temperatures and narrow safe density window pose serious challenges to the safe and efficient performance of deepwater water-based drilling fluids. Low temperatures can lead to physical and chemical changes in the components of water-based drilling fluids and the behavior of low temperature gelation. As a coarse dispersion system, water-based drilling fluid has a complex composition of dispersed phase and dispersing medium. Further clarification of low temperature gelation would be helpful in developing technical approaches to enhance the flat rheology performance of deepwater water-based drilling fluids. In this paper, different components are separated in order to comprehensively analyze the gelation behavior of different materials in water-based drilling fluids at low temperatures. In the first place, the rheological and hydrodynamic radius alterations of inorganic salts, bentonite, and additives in aqueous solutions were examined at low temperatures. The effects of inorganic salts, bentonite, and additives on the purified water system were investigated at low (4 °C)–normal (25 °C)–high (75 °C) temperatures. The low temperature gelation of different materials in pure water systems are fully clarified. The mud containing 4% bentonite with weak low temperature gelation commonly used in deepwater water-based drilling fluids was selected as the basic test system. Inorganic salts, additives, and solid-phase materials were added to the mud containing 4% bentonite. The effects of the interactions between different materials and bentonite particles on the low temperature gelation behavior of mud were analyzed. The higher the bentonite dosage, the stronger the low temperature gelation behavior of mud. The higher the addition of inorganic salts, the more serious the low temperature gelation behavior of mud. Inorganic salts should be avoided as much as possible to add too much. The low temperature gelation behavior of mud with low-viscosity additives is weak. However, the viscosity of mud with high-viscosity additives has a small change in viscosity with increasing temperature. The low temperature gelation of mud with the addition of solid-phase particulate materials with reactive groups on the surface is strong, and the low temperature gelation with the addition of inert particles is weak. This paper elucidates the low temperature gelation mechanism of bentonite, inorganic salts, additives, and solid-phase materials in deepwater water-based drilling fluids. The conclusion can also be used to guide the construction of a drilling fluid system, which is of great significance for the research and development of deepwater water-based drilling fluid additives and the safe and efficient performance of deepwater drilling fluids.

Dispersive solid phase extraction of 18 PFAS from environmental water samples using a novel MOF-polymeric monolith composite followed by High-Resolution mass spectrometry analysis

Metal-organic frameworks (MOFs) have been broadly coupled with many pretreatment techniques due to their remarkable attributes including high porosity, significantly increased specific surface area, and chemical stability, but their nanoscale dimensions make their handling challenging. To overcome this, a novel MOF-polymeric monolith composite was synthesized and studied as a novel sorbent material in an analytical technique. A rapid and efficient method for the extraction of a mixture of 18 per- and poly-fluoroalkyl (PFAS) compounds from environmental water samples was established based on MOF-polymeric monolith composite assisted dispersive solid phase extraction (d-SPE). The analytical methodology was carried out with the aid of liquid chromatography tandem high-resolution mass spectrometry. Several parameters influencing the extraction efficiency were comprehensively evaluated and optimized. The optimization was based on two processes: the one-variable-at-a-time approach (OVAT) and the central composite design (CCD). Preliminary studies were conducted and the extraction and elution time, as well as the sample volume were evaluated by adopting OVAT approach. The optimal parameters were found to be 15 min for extraction time, 5 min for the elution time and 10 mL as sample volume. Under the optimum conditions, the sample pH, sorbent amount and eluent volume were all evaluated under the design of experiments (DoE). ANOVA demonstrated the suitability of the suggested model with a p-value of less than 0.05 and various diagnostic tests validate the well-fitting results. The software extracted the optimal conditions which were pH = 7, sorbent amount = 10 mg and eluent volume = 750 μL. The method was subsequently validated with respect to accuracy, linearity detection limits and reproducibility. The proposed method presented recoveries over 70 %, method detection limits 1–46 ng/L and relative standard deviations <20 %. Before the implementation of the method in real samples, the “green” character was evaluated using the ComplexGAPI index, indicating the satisfactorily “green” character of the new MOF-based dSPE-LC-HRMS method. Finally, the efficacy of the method for determining PFASs in four environmental water matrices was tested using several matrices of varying complexity, including wastewater effluent, river water, marine water, and runoff.

Rheology and magnetorheology of ferrofluid emulsions: Insights into formulation and stability

The integration of surfactants and nanoparticles in emulsion formulations has attracted significant attention due to their potential synergistic effects, improving stability and enabling the development of stimuli-responsive materials. The objective of this study was to investigate the stability, bulk rheological, and magnetorheological properties of oil in water (o/w) emulsions, composed of Fe3O4 kerosene-based ferrofluids dispersed in surfactant solutions (hexadecylpyridinium chloride, and nonylphenol polyethoxylate—ethylene oxide = 40, known as Tergitol NP-40), as a function of concentration and nature of the emulsifying agents. The results demonstrated the formation of stable systems (&amp;gt;2 months), featuring an average droplet size below 4 μm, with the primary stabilization mechanism attributed to the reduction of interfacial tension by surfactant activity. The emulsions exhibited shear thinning and viscoelastic solid-like behavior, which were enhanced by increasing the concentrations of both emulsifiers. Emulsions stabilized with hexadecylpyridinium exhibited a higher structural rigidity, with dynamic moduli an order of magnitude higher than Tergitol formulations. In the presence of a perpendicular magnetic field, it was demonstrated that incorporating ferrofluid as a dispersed phase in an o/w emulsion potentiates the magnetoviscous effect, compared to that observed with neat ferrofluid at the same concentration. A maximum relative increase in viscosity of up to 17-fold was observed in emulsions stabilized with 2.5 w/v% of hexadecylpyridinium and 10 000 ppm of nanoparticles when exposed to a linearly increasing magnetic field up to 796.73 mT at 1 s−1. The observed magnetoviscous effect remained reproducible for up to one year after formulation, highlighting the potential of these systems for multiple applications.

Changing the Oral Tribology of Emulsions Through Crystallization of the Dispersed Triglyceride Phase.

Suspoemulsions are used for food, cosmetic and pharmaceutical products, including food such as dairy products and non-dairy alternatives. Product properties, such as flow behavior or sensory perception of non-dairy products differ from those of dairy products and are therefore perceived by consumers as products of inferior quality. One reason for this may be the crystallization behavior of the added triglycerides leading to differences in solid fat content in comparison to cow milk. This is discussed with the solidity of the dispersed phase as a parameter of suspoemulsions. The solidity was varied by using low and high melting triglycerides and measuring at different temperatures. The dispersed phase fraction is φ = 30%. The droplet size distribution showed a x50,3 of 1.2 and 3.66 μm, mimicking the droplet sizes of milk and dairy cream. Rheological frequency sweeps were carried out within a temperature range from 5°C to 50°C. The differences in solidity of the dispersed phase caused no changes in viscosity at each temperature. In contrast, oral tribology distinguished different solidities of the dispersed phase with changes in the friction coefficient. The friction coefficient was determined for increasing rotational speeds (0.01-100 mm/s), to compare the so called Stribeck curves with each other. In general, with increasing solidity of the dispersed phase, the friction coefficient increases. Comparing the Stribeck curves of pure butter fat suspoemulsion with those of plant-based fat suspoemulsions, different plant-based fats can be mixed, to mimic the friction profile of milk products in plant-based alternatives.

Study of Sand Transport in a Horizontal Pipeline Using Validated Computational Fluid Dynamics Simulations with Experimental Fiber-Optic Distributed Acoustic Sensing Data

Summary Sand management in wellbores is a significant challenge in the industry, notably impacting equipment integrity and operational safety—particularly in offshore oil and gas operations affected by the onset of sand production along with hydrocarbons. Recent advancements in fiber-optic sensing, especially through distributed acoustic sensing (DAS) experimental data, have enabled the continuous monitoring of sand ingress and migration. In this study, we use computational fluid dynamics (CFD) to accurately model sand transport by validating the simulations against the DAS data in a 40-ft-long, 2-in.-diameter experimental flow loop. The validation and verification (V&amp;V) process demonstrates the CFD model’s accuracy in both steady-state and transient conditions, through predictions of key flow parameters such as sand slip velocity, sand concentration profiles, and sand arrival times against published experimental data, as well as verification of CFD methodology against similar simulation studies. Next, we used the CFD model to simulate the fiber-optic experimental DAS data for sand slurry transport in a pipe through an injection port with conditions of carrier fluid velocity = 0.93 m/s and dispersed phase (sand) particle diameter of 300 µm at a concentration of 0.001 v/v. To address uncertainties during sand production, a parametric study under transient conditions was conducted with varying boundary conditions in the CFD model. It examined fluid flow velocities at both 0.53 m/s and 0.93 m/s, below and above the critical settling velocity of the sand respectively, and the effects of varying sand particle diameters (125 µm and 600 µm). Our research represents a significant advancement in sand management strategies, offering a robust and cost-effective tool for simulating real-world scenarios to improve operational efficiency. By providing detailed insights into flow dynamics and enabling robust predictions across various conditions, this study contributes substantially to advancing sand management strategies that could effectively mitigate operational risks and optimize sand transport in real time.

Adsorption mechanism of soy protein amyloid fibrils with different morphological structures at the interface of oil-in-water emulsion

Under specific processing conditions, globular food protein can form amyloid fibrils with excellent functional properties in food processing. Amyloid fibrils can be adsorbed on the surface of oil droplets to improve the stability of oil-in-water emulsion. The protein can form monomers oligomers, protofibrils and mature fibrils of which the concentrations increase with the prolonging acidic-heating time. However, the structural advantages of these aggregates when adsorbing at oil-water interface are unclear and the emulsifying ability and adsorption mechanism of food protein amyloid fibrils with different morphology at oil-water interface need to be studied in depth. Herein, four kinds of soy protein amyloid fibrils (SAFs) with distinct morphology were prepared by changing the acidic heating time (3, 6, 12 and 24 h), which were referred as SAFs-3, SAFs-6, SAFs-12 and SAFs-24. Their interfacial adsorption behavior at the oil-water interface were studied systematically by three-phase contact angle, interfacial tension, CLSM, Cryo-SEM and other characterization techniques. The results suggested that the length and flexibility of the fibrils have a great influence on the interface properties, including the rheological properties such as viscosity and modulus. These properties determine the emulsifying capacity of the fibrils. The emulsion stabilized by SAFs-12 was the most resistant to coalescence because SAFs-12 formed a stronger interfacial layer around the oil droplets and a denser viscoelastic network in the continuous phase. In our study, a stabilizing emulsion was prepared using SAFs, which provided potential applications for amyloid fibrils in the food field.

Four-dimensional flow characteristics of air-entrained turbulent impinging waterjet onto quiescent water surface

This paper presents a time-resolved three-dimensional (4D) flow fields measurement of the continuous phase of a turbulent impinging jet inducing foam formation using the Lagrangian particle tracking velocimetry utilizing the Shake-The-Box algorithm. With the systems equipped with four high-speed cameras, time-series of images of fluid tracer particles were acquired. The Vortex-In-Sharp (VIC#) method was used to reconstruct the Eulerian flow fields of the particle tracks. The impinging jet was characterized as plume-like along the vertical direction with two distinct layers: developing shear and fully developed shear. The streamwise vortex structures of the continuous phase were influenced by the bubble plume motion, and the results showed high amplitude oscillations of the acceleration and deceleration near the jet source resulting in the formation of ring-like vortices, which break down as the jet moves downstream with its momentum dissipated. The flow of the continuous phase of impinging jet was self-similar both at the developed shear layer and the fully developed diffusion layer beneath the water pool and is characterized as homogeneous shear flow with anisotropy turbulence. The classical assumption of self-similarity with Gaussian profiles for continuous phase velocity is verified experimentally. We found that the results show a huge potential of blue energy harvesting from the low frequency (∼2 Hz) dissipating kinetic energy of the turbulent plume-like jet underneath the impinging water surface using triboelectric nanogenerator.