Non-miscible Liquids Research Articles

Pulsatile flow of Casson hybrid nanofluid between ternary-hybrid nanofluid and nanofluid in an inclined channel with temperature-dependent viscosity

This study presents a mathematical model for layered non-miscible liquid flow in an inclined channel subject to a pulsatile pressure gradient. The Casson hybrid nanofluid (hnf) is sandwiched between the layers of Newtonian ternary hybrid nanofluid (t-hnf) and nanofluid (nf). Additionally, the impact of temperature-dependent viscosity is taken into consideration. Multiwall carbon nanotubes, molybdenum disulfide, and silver are considered nanoparticles, with water and kerosene oil as base fluids. The governing partial differential equations are transformed into coupled non-linear ordinary differential equations (ODEs) using the perturbation technique. The resulting ODEs are solved numerically using MATHEMATICA software with the help of the shooting technique associated with the Runge-Kutta fourth-order scheme. The behaviors of numerous sundry parameters against velocity, temperature, concentration, and shear stress are depicted graphically and in tabular form. The outcomes of the study reveal that if the viscosity is held constant, then the fluid’s velocity is initially low and gradually increases as the viscosity variation parameter rises. The velocity of fluid flow is higher when a Newtonian fluid occupies the middle region of the channel than when Casson fluid does. The increase in the nanoparticle shape factor, at both boundaries, results in an increase in the rate of heat transfer.

Coalescence Initiation in Liquid-Liquid Systems: A Stochastic Model.

Coalescence is a complex phenomenon leading to the merging of deformable particles of fluid. The complexity stems largely from the simultaneous occurrence of phenomena of a different nature (hydrodynamic, electrostatic, physicochemical) acting at different scales. The stochastic effects controlling the formation of the liquid bridge between two droplets of the same liquid, immersed in another nonmiscible liquid, are studied through a series of molecular dynamics simulations. The case of heptane droplets in water, relevant to solvent extraction, a key process of the circular economy, is considered. From this series of simulations, we have confirmed that the probability function of coalescence of two identical droplets in contact follows a Poisson distribution. We moreover propose a criterion for the initiation of coalescence based on nucleation theory. A complete description of the stochastic initiation of coalescence is hence provided, opening many perspectives for the simulation of coalescence in continuous approaches used in fluid mechanics and chemical engineering. The methodology can be generalized to droplets of different size and composition, immersed in gas, or to bubbles, i.e., to other physical problems whose kinetics is influenced by the molecular scale.

Microemulsions and Nanoemulsions in Skin Drug Delivery

Microemulsions and nanoemulsions are lipid-based pharmaceutical systems with a high potential to increase the permeation of drugs through the skin. Although being isotropic dispersions of two nonmiscible liquids (oil and water), significant differences are encountered between microemulsions and nanoemulsions. Microemulsions are thermodynamically stable o/w emulsions of mean droplet size approximately 100–400 nm, whereas nanoemulsions are thermodynamically unstable o/w emulsions of mean droplet size approximately 1 to 100 nm. Their inner oil phase allows the solubilization of lipophilic drugs, achieving high encapsulation rates, which are instrumental for drug delivery. In this review, the importance of these systems, the key differences regarding their composition and production processes are discussed. While most of the micro/nanoemulsions on the market are held by the cosmetic industry to enhance the activity of drugs used in skincare products, the development of novel pharmaceutical formulations designed for the topical, dermal and transdermal administration of therapeutic drugs is being considered. The delivery of poorly water-soluble molecules through the skin has shown some advantages over the oral route, since drugs escape from first-pass metabolism; particularly for the treatment of cutaneous diseases, topical delivery should be the preferential route in order to reduce the number of drugs used and potential side-effects, while directing the drugs to the site of action. Thus, nanoemulsions and microemulsions represent versatile options for the delivery of drugs through lipophilic barriers, and many synthetic and natural compounds have been formulated using these delivery systems, aiming to improve stability, delivery and bioactivity. Detailed information is provided concerning the most relevant recent scientific publications reporting the potential of these delivery systems to increase the skin permeability of drugs with anti-inflammatory, sun-protection, anticarcinogenic and/or wound-healing activities. The main marketed skincare products using emulsion-based systems are also presented and discussed.

Switchable smart porous surface for controllable liquid transportation.

Controllable liquid transportation through a smart porous membrane is realized by manipulating the surface wetting properties and external stimuli, and has been intensively studied. However, the liquid transportation, e.g., permeation and moving process, at the interface is generally uninterrupted, i.e., the opening and closing of the interface is irreversible. Herein, we present a new strategy to achieve magnetic adaptive switchable surfaces, i.e., liquid-infused micro-nanostructured porous composite film surfaces, for controllable liquid transportation, via modulation of the magnetic field. The liquid transportation process can be interrupted and restarted on the porous composite film because its pore structure can be quickly closed and opened owing to the adaptive morphological transformation of the magnetic liquid with a varying magnetic field. That is, the liquid permeation process occurs due to the open pore structure of the composite film when the external magnetic field is added, while the permeation process can be interrupted owing to the self-repairing closure of the pore when the magnetic field is removed, and the moving process can be achieved. Thus a magnetic field induced switchable porous composite film can serve as a valve to control liquid permeation based transportation, which opens new avenues for artificial liquid gating devices for flow, smart separation, and droplet microfluidics.

Optimization of microemulsion cleaning sludge conditions using response surface method

Microemulsion cleaning method has been proved to be an effective way to clean oily sludge with low interfacial tension and high solubilizing ability for non-miscible liquids. In this paper, the percentage range of the microemulsion in the formulation was obtained by studying phase behavior of the microemulsion. The response surface method was used to model and optimize the microemulsion to obtain the best formulation: n-BuOH content at 9.89%, NaCl content at 2.24% and AES/APG ratio at 3.75, and the oil removal rate reached 97.28%. Meanwhile, the cleaning conditions of oil sludge were also optimized by the response surface method and the optimal cleaning parameters were determined as liquid-solid ratio at 4.2, stirring rate at 157 r·min−1, and stirring time at 38 min. In addition, some experiments were carried out to confirm the simulation results, affording the oil removal rate of 98.79%. SEM and FTIR confirmed that the oil on the sludge can be removed by microemulsion.

Measurement and modeling of electrowetting lens oscillations using digital holographic interferometry and Bessel and Legendre polynomial functions.

The function of electrowetting liquid lenses is expanding beyond tunable focal length lensing. Recently, single and multi-mode oscillations on the meniscus profile of two non-miscible liquids have been used for optical phase modulation and fast focal length sweeping. To achieve a user-defined phase modulation, a prediction model of oscillation patterns and amplitudes is needed. We present digital holographic interferometry (DHI) measurements of oscillation patterns and amplitudes on a 5.8mm aperture lens up to 160 Hz, including frequency responses from 26-100 Hz. We discuss using Bessel function and Legendre polynomial models for oscillations on a conical frustum shaped electrowetting lens.

Influence of Sample Mixing Techniques on Engine Oil Contamination Analysis by Infrared Spectroscopy

For the most reliable and reproducible results for calibration or general testing purposes of two immiscible liquids, such as water in engine oil, good emulsification is vital. This study explores the impact of emulsion quality on the Fourier transform infrared (FT-IR) spectroscopy calibration standards for measuring water contamination in used or in-service engine oil, in an attempt to strengthen the specific guidelines of ASTM International standards for sample preparation. By using different emulsification techniques and readily available laboratory equipment, this work is an attempt to establish the ideal sample preparation technique for reliability, repeatability, and reproducibility for FT-IR analysis while still considering the ease and efficiency of the technique. This study demonstrates that a stable emulsion within a sample, which depends heavily upon the method, provides a reliably consistent homogenous sample for quantification purposes with FT-IR analysis. Analysis of variance (ANOVA) modeling and limit of detection calculations demonstrate the stability of the emulsion. The results reveal that setting a mixing time for a calibration standard depends on the emulsification process. Inserting a probe directly into a sample (direct sonication) allows for a rapid, stable emulsion with high reproducibility. Indirect sonication produces relatively non-miscible liquids of different densities. The pan-shaker produces a reasonably stable emulsion, but without the long-term stability or quick production time of direct sonication. Reaction time plays a critical role in the rotary mixing method, which leads to a slow development of emulsification.

A Possible Infinite Number of Components in a Single Crystalline Phase: On the Isomorphism of Brivaracetam–Guest Molecules

This article highlights the unusual behavior of brivaracetam (BRV: an active pharmaceutical ingredient against epilepsy), which leads to a unique phase—ranging from clathrate to solvate to cocrystal—formed with an impressive number of apolar guest molecules (any linear alkanes to esters of fatty acids/alcohols, or waxes). Moreover, the investigation of binary systems between linear alkanes and BRV displayed the systematic existence of a syntectic invariant (one solid melts into two nonmiscible liquids) for CnH2n+2 with n > 7.

Factors influencing melt fluidity of iron ore

The melt fluidity (MF) of iron ore, which reflects the flow and bonding abilities of the melt, plays a significant role during sintering. In this study, the MF of iron ore was measured by the micro-sintering method, and the formation and flow of the melt were analyzed using Factsage 7.0. Additionally, chemical reagent simulation tests were conducted to determine the effects of chemical components and gangue mineral types on MF, and the effect of MF on sinter strength was studied by sinter pot tests. The results show that the sintering melt includes some non-miscible liquids and solids. The liquid phases of hematite and limonite ores include silico-ferrites of calcium and aluminum system (predominant) and silico-ferrites of calcium system, and those of the magnetite ores are CaO-FeO-Fe2O3-SiO2 systems. The MF of iron ore depends mainly on liquid amount and viscosity, which play opposite roles in increasing the MF. Moreover, SiO2 increases the MF, whereas Al2O3 and loss on ignition decrease the MF. Increasing the substitution proportion of quartz and gibbsite by kaolinite enhances the MF. The effect of MF of the ore blends on the shatter index of the sinter shows a trend of inverted “V”.

Transfer of colloidal particles between two non-miscible liquid phases

This work investigates a direct transfer of dispersed particles into another dispersion medium. The transfer is realized by layering the suspension above a second, non-miscible liquid. The particles are then transferred by centrifugation or mere sedimentation. The transfer is, unlike a liquid-liquid extraction, not only driven by thermodynamic effects such as favorable solubility, but is based on an additional mechanical work input. Here the transfer of a colloidal particle system is discussed on the example of SiO2 particle dispersions with regards to the influence of particle size, viscosity, density and an emphasis on the effects of interfacial forces. For small particles it was found that hydrophilic and hydrophobic forces dominate and hinder the transfer as particles adsorb to the interface, which can be countered by an increase of centrifugation forces or reduction of surface forces with surfactants. The transfer is described in detail with a model to lay out the influence of all parameters, revealing a threshold size for a successful transfer at given conditions. The model is applied and tested on different SiO2 suspensions for verification.

Formation, Structure, and Functionality of Interfacial Layers in Food Emulsions.

Emulsions, i.e., the dispersion of liquid droplets in a nonmiscible liquid phase, are overwhelmingly present in food products. In such systems, both liquid phases (generally, oil and water) are separated by a narrow region, the oil-water interface. Despite the fact that this interface is very thin (in the nanometer range), it represents a large surface area and controls to a great extent the physicochemical stability of emulsions. This review provides an overview of the aspects that govern the composition, structure, and mechanical properties of interfaces in food emulsions, taking into account the complexity of such systems (presence of numerous surface-active molecules, influence of processing steps, and dynamic evolution due to chemical changes). We also review methods that have conventionally, or recently, been used to study liquid-liquid interfaces at various scales. Finally, we focus on the link between interfacial properties and the physical, chemical, and digestive stability of emulsions at different levels and point out trends to control stability via interfacial engineering.

Capillary imbibition of aqueous foams by miscible and nonmiscible liquids.

When put in contact with a large liquid drop, dry foams wick owing to surface-tension-driven flows until reaching equilibrium. This work is devoted to the dynamics of this imbibition process. We consider imbibition of both wetting or nonwetting liquid, by putting the dry foam into contact either with the foaming solution that constitutes the foam or with organic oils. Indeed, with the appropriate choice of surfactants, oil spontaneously invades the liquid network of the foam without damaging it. Our experiments show an early-time dynamics in t(1/2) followed by a late-time dynamics in t(1/4). These features, which differ from theoretical works predicting a t(1/3) dynamics, are rationalized considering the influence of the initial liquid fraction of the foam in the driving capillary force and the impact of gravity through the capillary-gravity equilibrium.

Capillary penetration in cellulose and polyethylene porous media: effect of contact with vapours and partial saturation with a non-miscible liquid

Abstract This work presents the effect of water and oil vapours and of partial liquid water saturation on the rate of capillary penetration in porous media. Two porous media were used: one made of cellulose (wettable both by oil and water) and the other made of polyethylene (wettable only by oil). Sunflower oil was the penetrating liquid. The porous structure of the porous media was characterized using SEM and surface properties were determined by FTIR. In addition, the effective pore radii and contact angles of sunflower oil against each medium were determined. The contact angle of sunflower oil against polyethylene was 0°, and no dynamic contact angle effects were observed. Capillary penetration of sunflower oil in cellulose showed contact angles around 80° in the beginning of penetration which gradually decreased to about 14°. The porous media were also put into contact with water vapours for different times and at different temperatures and results were compared with those obtained in the presence of oil vapours or in the absence of vapours. In addition, experiments were performed by fully saturating the cellulose porous medium with water and then partially drying it. The rate of capillary penetration of the oil in the polyethylene porous medium was not affected by the presence of vapours. On the contrary, the presence of water vapours and partial water saturation in the cellulose matrix significantly increased the penetration rate (up to almost three times) under most of the examined conditions. The reasons for such an effect are being discussed.

Stabilizing Liquid Drops in Nonequilibrium Shapes by the Interfacial Jamming of Nanoparticles

Nanoparticles assemble at the interface between two fluids into disordered, liquid-like arrays where the nanoparticles can diffuse laterally at the interface. Using nanoparticles dispersed in water and amine end-capped polymers in oil, nanoparticle surfactants are generated in situ at the interface overcoming the inherent weak forces governing the interfacial adsorption of nanoparticles. When the shape of the liquid domain is deformed by an external field, the surface area increases and more nanoparticles adsorb to the interface. Upon releasing the field, the interfacial area decreases, jamming the nanoparticle surfactants and arresting further shape change. The jammed nanoparticles remain disordered and liquid-like, enabling multiple, consecutive deformation and jamming events. Further stabilization is realized by replacing monofunctional ligands with difunctional versions that cross-link the assemblies. The ability to generate and stabilize liquids with a prescribed shape poses opportunities for reactive liquid systems, packaging, delivery, and storage.

Dewetting of Low-Viscosity Films at Solid/Liquid Interfaces

We report new experimental results on the dewetting of a mercury film (A) intercalated between a glass slab and an external nonmiscible liquid phase (B) under conditions of a large equilibrium contact angle. The viscosity of the external phase, ηB, was varied over 7 orders of magnitude. We observe a transition between two regimes of dewetting at a threshold viscosity of η(B)* ≈ (ρ(A)e|S̃|)(1/2), where ρ(A) is the mercury density, e is the film thickness, and |S̃| is the effective spreading coefficient. For η(B) < η(B)*, the regime is inertial. The velocity of dewetting is constant and ruled by Culick’s law, V ≈ (|S̃|/(ρ(A)e))(1/2). Capillary waves were observed at high dewetting velocities: they are a signature of hydraulic shock. For η(B) > η(B)*, the regime is viscous. The dewetting velocity is constant and scales as V ≈ |S̃|/η(B) in the limit of large η(B). We interpret this regime by a balance between the surface energy released during dewetting and the viscous dissipation in the surrounding liquid.

The Research to Hydrocyclone Desander of Sand Removing Based on Crude Oil

The fractional volume of the reservoir sand shall be taken to the ground when the crude oil is brought up from the ground. With the deepening of the oil extraction the sand content of oil recovery is increasing. Although many measures have been used such as prevent sand, block sand and so on, the viscosity of heavy oil is big and the fractional of sand is carried into the crude oil gathering system inevitably, causing a series of problems at ground equipment, having a serious impact on the normal production and gathering of crude oil. The larger size of sand can be removed by the sedimentation and the smaller sand can be removed by hydrocyclone devices. Hydrocyclone is a separation plant used to separate non-uniform phase mixtures. It can be used to complete the liquid clarification and to wash particles, liquid degassing and grit removal, grading and classification of solid particles and the separation of two non-miscible liquids and others. Hydrocyclone separation technique is simple and convenient operation, high separation efficiency, no rotating units, small size and easy to realize automatic control. On the offshore platform，if the sand mixed with oil is discharged into sea unsatisfactory the standard, it will pollute the sea. It will cause a serious of marine pollution; this is a problem that should be solved quickly. This paper discusses the requirements for the design of the hydrocyclone desander equipment with compact structure, applicable to offshore drilling platforms，and carrying out CFD simulation, the results showing that the particle size of 75 of sand, grit removal efficiency above 90%.

Biological Removal of Siloxanes from Landfill and Digester Gases: Opportunities and Challenges

The presence of volatile methyl siloxanes (VMSs) presents challenges for using landfill and digester gases as energy fuels because of the formation of silicon dioxide deposits during combustion. This study looks at the feasibility of using biological treatment to control VMSs. Biotrickling filters removing octamethylcyclotetrasiloxane (D4), selected as a model VMS, from aerobic and anaerobic waste gas streams were setup. The efficacy of both aerobic and anaerobic biotrickling filters was low. The removal of D4 in the aerobic biotrickling filter followed a linear trend, reaching 43% at a gas empty bed residence time of 19.5 min. Aerobic biodegradation of D4 in shake flasks was found to be extremely slow, with trace concentrations requiring 3-4 months for complete degradation. Gas-liquid partition tests revealed that D4 partitions poorly into aqueous phases and that interphase mass transfer is slow. Using the mass transfer data, we estimated the maximum possible mass transfer rate of D4 in the biotrickling filter to be in the range of 30-100 mg m(-3) h(-1). These values are low and suggest that mass transfer limitations play an important role in the low treatment performance that was observed. The possibility of enhancing D4 mass transfer by using oleyl alcohol as a second nonmiscible liquid phase was unsuccessful. Overall, the results demonstrate that biological treatment of D4 vapors is possible but poses significant challenges.

Electrowetting --A versatile tool for controlling microdrop generation

Integrating insulator-covered electrodes into a microfluidic flow focusing device (FFD) we demonstrate enhanced flexibility and control of the flow of two non-miscible liquids based on electrowetting (EW). In the parameters space, determined by liquid inlet pressures, we identify a specific region where drops can only be generated and addressed via EW. In this regime we show that the size distribution and the frequency of drop generation can be controlled by the applied voltage and the width of voltage pulses. Moreover it turns out that with EW the drop size and the frequency can be tuned independently. Finally we show that the same drop generation phenomena can also be observed in the presence of surfactants.

Formulation and characterisation of beads prepared from natural cyclodextrins and vegetable, mineral or synthetic oils

A continuous external shaking for 2.5 days of a mixture composed of α-cyclodextrin (6%), soybean oil (19.6%) and water (74.4%) resulted in a calibrated lipid carrier namely bead with a high fabrication yield. The purpose of this work was to explore the possibility to substitute α-cyclodextrin by other natural cyclodextrins, i.e. β- and γ-cyclodextrin and then soybean oil by mineral (Primol ® 352 and Marcol ® 82) or synthetic (Silicon 200 ® fluid 10, 50 or 100cSt) oils. Beads can be successfully prepared using Marcol ® 82 with α-cyclodextrin and Silicon 50 or 100cSt with γ-cyclodextrin. The area inside oil/cyclodextrin/water ternary diagram corresponding to bead occurrence was superior for the Marcol ® 82/α-cyclodextrin couple compared to that observed with soybean oil/α-cyclodextrin couple. Only a few ratios of Silicon 50 and 100cSt/γ-cyclodextrin/water led to beads. The combinations which did not induce bead occurrence gave either emulsions, two non-miscible liquids or a solid mixture. Whatever the materials used, beads exhibited similarities: presence of a crystalline organisation and viscoelastic properties. Manufacturing process of paraffin- and silicon-based beads need further optimisation to increase fabrication yield and later on, to take advantages from the high stability of both oils for the formulation of drugs with beads.

Automatic Sprinkler Protection of Palletized, 55 Gallon Drum Storage of Unsaturated Polyester Resins

Unsaturated polyester resin (UPR) is used extensively in the production of composite plastic materials, such as fiberglass products. UPRs are classified by NFPA 30 as Class I flammable liquids, often Class IC, based on their styrene content. However, because UPR is a viscous liquid with a low vapor pressure and a high-density, it was postulated that UPR stored in drums might behave more like a melted plastic than a non-miscible Class IC liquid when subjected to fire. This could enable the use of reduced fire protection system designs as compared to protection schemes ordinarily required by NFPA 30 for Class IC liquids.