Dispersive Liquid Research Articles

Dispersion of immiscible liquids in a static mixer without inserted elements: A CFD-PBM study on droplet size reduction and distribution

Dispersion of immiscible liquids in a static mixer without inserted elements: A CFD-PBM study on droplet size reduction and distribution

Reversibly thermosecreting and convertible lubricative oil-in-water mixtures using multiple hydrogen bonding interactions

Achieving homogeneous oil and water mixing requires thorough droplet dispersions of both liquids. An additional component, such as a surfactant, particle, solvent or ion is normally required to stabilize the small liquid droplets by providing sufficiently low interfacial tensions or strong repulsive forces. Here we show that very stable oil-in-water mixtures can be created even at very high oil volume fractions by building multiple, high-strength hydrogen bonding interactions between water and a biocompatible and biodegradable oil trimethylolpropane trioleate, which make the oil molecules at the contact interface behave as pseudo-surfactants with ultrahigh interfacial activity. The resultant oil microdroplets can be reversibly thermosecreted from the continuous aqueous phase and lead to controllable formation/dissociation and switchable lubrication of the binary liquid mixture owing to the inherent thermal responsiveness of the intermolecular hydrogen bonding. Interestingly, although water is uncovered to possess a relatively poor lubricity, the liquid mixture yields an optimized lubrication that is even exceedingly comparable to pure oil at a water volume fraction as high as 80%.

Numerical study of the effect of barrier wall on liquid hydrogen leakage and dispersion

Numerical study of the effect of barrier wall on liquid hydrogen leakage and dispersion

INTEGRATION OF HIGH-TEMPERATURE SURFACE HEAT EXCHANGE

Despite the discrete nature of the interaction of droplets of sprayed liquid with a high-temperature surface, the inevitable formation of a liquid film leads to the fact that the main qualitative laws of the heat exchange that occurs in this case are characteristic of the known process of heat exchange during boiling. At the same time, the presence of extensive theoretical and experimental studies of “large-volume boiling” and the process of steam generation in channels does not allow us to establish the conditions of heat exchange during the thermal interaction of a dispersed liquid - water with different concentrations of surfactants with a high-temperature surface. We did not find any materials about this process in the scientific literature. With a number of features common to the above two cases of heat exchange (the presence of boiling crises, film and bubble modes, etc.), cooling a high-temperature surface with a droplet medium containing various concentrations of surfactants has significant distinctive features due to the hydrodynamics of the process, which is the subject of further study. To fully explore the above task, the following must be done: Develop a methodology for experimental study of local conditions of non-stationary heat exchange of sprayed water with different concentrations of surfactants. Develop and manufacture an experimental setup on which to conduct research on the effects of irrigation density, surface temperature, degree of liquid underheating, its speed and angle of impingement on the surface. Develop a mathematical model for calculations of heat flows, heat transfer coefficients, dynamics of hydraulic methods of liquid dispersion – water with different concentrations of surfactants, critical heat flows and surface temperatures in the transition region from film to bubble boiling as a function of determining factors. Establish the independent influence of the degree of non-stationarity of the process on the heat exchange conditions.

Polythermal studies of the water – propylene glycol systems by densitometry, viscometry and spin probes method

Based on the determined values of density, dynamic viscosity and molar volumes, the thermodynamic activation parameters and excess thermodynamic activation parameters of viscous flow at temperatures from 293.15 K (20°C) to 313.15 K (40°C) were calculated for the mixed binary solvents water – propylene glycol (PG). Using the isotherms at 298.15 K, assumptions were made about the composition regions of binary solvents with different structural organizations. The structure of the mixed solvent has an impact on the various functional characteristics of the systems water – PG, and it could also influence the performance of medicinal products with a liquid dispersion medium. The density and excess density, as well as the dynamic viscosity and excess dynamic viscosity for systems water – PG were determined as a function of the PG concentration. Using the method of spin probes, it was demonstrated that changes in the dynamic viscosity of systems water – PG correlated with the alterations in the viscosity of the microenvironment of spin probe molecules. The viscosity of the microenvironment was also influenced by the interaction between molecules of dissolved spin probes and solvent molecules.

INTENSITY OF CHEMICAL NEUTRALISATION OF CHLORINE DURING PRECIPITATION BY A FINELY DISPERSED LIQUID STREAM

One of the main tasks of the unified state system of civil protection is to forecast and assess the socio-economic consequences of emergencies, determine the need for forces, means, material and financial resources based on the forecast; carry out rescue and other urgent work to eliminate the consequences of emergencies, and organise life support for the affected population. The paper modifies the model of chlorine sorption by a fine liquid flow. The developed mathematical model allows to take into account the following basic parameters of sorption, environmental parameters, parameters of the liquid flow supplied for deposition and physical and chemical properties of the liquid in this flow. The developed model allows minimising the number of input parameters and the forecasting time, which is critical for emergency response. The results of numerical modelling have shown that the deposition of chlorine, which is a low-valent gas in water, is determined by the Henry's constant, and not by the intensity of the liquid flow, as previously thought. The poor solubility of chlorine in water does not provide significant efficiency (6% compared to ammonia) of its deposition by dispersed streams even at maximum intensity, which confirms the need for rescue units to use water-soluble additives that are chemically active to react with chlorine. It is also worth noting the logarithmic nature of the dependence of gas deposition intensity on the intensity of the dispersed flow. This can be explained by the fact that the intensity of sorption decreases due to a decrease in gas concentration, which in turn decreases due to the absorption process. Therefore, it is possible to determine the critical intensity of the liquid dispersion flow at which the sorption intensity almost stabilises. This confirms the urgent need for rescue units to use chemical neutralisers in the elimination of accidents involving chlorine emissions into the atmosphere.

Novel continuous in situ measurement of photocatalyst efficiency in liquid dispersions by laser absorption method

This work presents a novel method and reactor design for measuring photocatalytic activity. This method allows continuous in situ monitoring of the decrease in pollutant concentration in a liquid dispersion containing the tested photocatalyst. Due to the presence of the photocatalyst in the liquid dispersion, the standard Beer-Lambert absorption law cannot be used directly to determine pollutant concentration in photocatalytic measurements. Therefore, the presented in situ measurement method also utilizes a newly derived modification of the absorption law, which, in addition to absorption, also considers the scattering effect caused by the dispersed photocatalyst. Repeated correlation analysis showed an average deviation of only 1.04% from approximately 500 measurements. At the same time, the measured points obtained by the presented method were within the uncertainty intervals of the standard method for measuring photocatalytic activity. It has been demonstrated that this novel continuous in situ measurement method can replace the current standard measurement method and can provide an even more consistent and faster way of testing photocatalytic materials. In addition, a novel and open source (patented experimental setup for the photocatalytic reactor system, consisting of a spectrometric laser and probe, is fully described in this paper.

Aqueous Dispersion of Xenes by Liquid Phase Exfoliation of Monoelemental Crystals in Melamine Solution.

Αfter the impressive evolution of graphene and its derivatives, a large number of two dimensional (2D) materials with important optical and electrical properties have been successfully fabricated. Liquid phase exfoliation (LPE) of layered and non-layered materials has become a widely applied method for the preparation of 2D nanostructures with an extensive variety of applications. However, in most cases organic solvents are used as liquid phase which are often toxic and environmentally unfriendly and lead to low yields. In this work, we present water as a suitable liquid phase and dispersion medium for the exfoliation of layered and non-layered monoelemental solids from IVA, VA and VIA groups of the periodic table, such as silicon, tin, bismuth and tellurium. The 2D nanostructures, silicene, stanene, bismuthene and tellurene are therefore prepared by a completely sustainable and environmentally friendly method. The prepared Xenes, as they are called, are fully characterized by microscopic and spectroscopic techniques.

Dynamics of two bubbles colliding at high Reynolds numbers in water: Bubble rebound behavior study

AbstractThe collision between bubbles is essential to gas–liquid dispersion systems. When bubbles encounter each other, they may either rebound or coalesce. Yet, little is known about the rebound dynamics immediately after two bubbles collide. This work investigates such collision dynamics of two bubbles at high Reynolds numbers in water through experiment and simulation. The moving velocity, deformation, contact time during collision and restitution coefficient of bubbles are analyzed. Simulations reproduced quantitatively the bubble rebound behavior, revealing the evolution of various energies involved in collision. Simulation results show that over 70% of the system's initial mechanical energy (SME) could be converted into bubble surface energy (BSE) during the approach. In turn, the excess BSE is converted back into SME driving bubbles to rebound with significant dissipation. A mass‐spring‐damper model is developed, which describes the dynamic of bubble rebound well. This contribution enhances the understanding of bubble interactions in multiphase flow.

Investigating the effect of hole size, bottom hole temperature, and composition on cement bonding quality of exploratory wells in Iran

The oil and gas industry’s reliance on well cementing practices to ensure well integrity and productivity is a pressing concern, particularly in exploratory wells where unpredictable conditions can lead to subpar cement bonding efficiency. This study addresses the pressing issue of optimizing cementing practices in Iran’s exploratory wells, ensuring better well integrity and productivity. The preliminary objective is to investigate the impact of hole size and bottom hole temperature variations on cement bonding efficiency in these wells. We analyzed cement quality logs from 21 exploratory wells in reservoir zones between 2012 and 2022 to achieve this. The study employed a systematic approach, using CBL/VDL and cement formulation to assess the quality of each wellbore section separately. We designed a cement formulation based on changes in bottom hole temperature and gas migration control and implemented it using three different contractors, each with unique additives. It allowed us to compare the quality of cement resulting from different phases and additives. Our results show that cement designed with dominant liquid additions in the 5-inch liner phase exhibits better bonding than formulations with increased powder form additives, specifically those containing a liquid dispersant, liquid fluid loss controller, liquid anti-gas migration, and liquid H.T. retarder for LNR 5 inch. Additionally, smaller hole sizes demonstrate better cement bonding quality due to reduced fluid flow and less turbulence. These findings have significant implications for optimizing cementing practices in the petroleum industry, particularly in Iran’s exploratory wells. Overall, this investigation provides valuable insights for improving wellbore integrity and productivity by optimizing cementing practices, which can be applied to future drilling operations in Iran’s exploratory wells.

Solution Processable Metal-Organic Frameworks: Synthesis Strategy and Applications.

Metal-organic frameworks (MOFs), constructed by inorganic secondary building units with organic linkers via reticular chemistry, inherently suffer from poor solution processability due to their insoluble nature, resulting from their extensive crystalline networks and structural rigidity. The ubiquitous occurrence of precipitation and agglomeration of MOFs upon formation poses a significant obstacle to the scale-up production of MOF-based monolith, aerogels, membranes, and electronic devices, thus restricting their practical applications in various scenarios. To address the previously mentioned challenge, significant strides have been achieved over the past decade in the development of various strategies aimed at preparing solution-processable MOF systems. In this review, the latest advance in the synthetic strategies for the construction of solution-processable MOFs, including direct dispersion in ionic liquids, surface modification, controllable calcination, and bottom-up synthesis, is comprehensively summarized. The respective advantages and disadvantages of each method are discussed. Additionally, the intriguing applications of solution-processable MOF systems in the fields of liquid adsorbent, molecular capture, sensing, and separation are systematically discussed. Finally, the challenges and opportunities about the continued advancement of solution-processable MOFs and their potential applications are outlooked.

Using Rheology and Image Processing to Study the Effects of Cellulose Nanocrystal Sedimentation.

The effect of sedimentation on lyotropic liquid crystalline dispersions is both an interesting subject in colloidal science and is of practical importance for understanding changes that can occur during dispersion storage. This research explored how the seemingly subtle changes in average length resulting from a single sedimentation step affected the rheological properties and self-assembly of aqueous dispersions of sulfated cellulose nanocrystals. Sedimentation of a primarily isotropic aqueous cellulose nanocrystal dispersion for 1 month at ambient conditions resulted in an isotropic top phase and a biphasic bottom phase, which were separated for further study. Both atomic force microscopy measurements and intrinsic viscosities determined via Fedor's equation showed preferential fractionation of longer cellulose nanocrystals (CNCs) to the bottom phase. The effects of this fractionation on dispersion rheology and phase behavior were studied by preparing a range of concentrations from each phase. As expected, the concentration for the isotropic-biphasic phase transition was significantly lower for the bottom phase than for the top phase or parent dispersion. Rheological changes were generally subtle, but significant differences were seen in the storage modulus at concentrations approaching rheological gelation. Most notably, quantitative image processing showed that even this simple, single-step fractionation process had a significant impact on the relative proportion of tactoids and chiral helices with planar and homeotropic anchoring in self-assembled cellulose nanocrystal films. These results highlight the impact that changes in polydispersity due to sedimentation can have on the self-assembly of nanomaterial mesogens.

Bubble generation in a 3-D flow-focusing microchannel: From squeezing to jetting

Fine bubbles have been applied in many fields; however, the controllable preparation of monodispersed fine bubbles remains a challenge. In this study, a three-dimensional (3-D) flow-focusing microfluidic device was designed. Compared with bubble formation in one-dimensional (1-D) and two-dimensional (2-D) flow-focusing, the 3-D flow-focusing microchannel owns the features of making bubbles with much smaller sizes and wider operation range. Four different gas–liquid flow regimes (squeezing, squeezing-dripping transition, dripping, and jetting) and three different gas–liquid dispersion states (mono-dispersion, bi-dispersion, and poly-dispersion) were observed in the 3-D flow-focusing microchannels. Importantly, the bi-dispersion in the squeezing-dripping transition regime experimentally verified that the squeezing and viscous shearing mechanisms separately control bubble formation in the transition region based on the time sequence. The intrinsic reason for poly-dispersion in the squeezing-dripping transition and jetting regimes was revealed. Finally, a mathematical model is proposed to predict the bubble size in the flow-focusing microchannels.

Chiral, Topological, and Knotted Colloids in Liquid Crystals

The geometric shape, symmetry, and topology of colloidal particles often allow for controlling colloidal phase behavior and physical properties of these soft matter systems. In liquid crystalline dispersions, colloidal particles with low symmetry and nontrivial topology of surface confinement are of particular interest, including surfaces shaped as handlebodies, spirals, knots, multi-component links, and so on. These types of colloidal surfaces induce topologically nontrivial three-dimensional director field configurations and topological defects. Director switching by electric fields, laser tweezing of defects, and local photo-thermal melting of the liquid crystal host medium promote transformations among many stable and metastable particle-induced director configurations that can be revealed by means of direct label-free three-dimensional nonlinear optical imaging. The interplay between topologies of colloidal surfaces, director fields, and defects is found to show a number of unexpected features, such as knotting and linking of line defects, often uniquely arising from the nonpolar nature of the nematic director field. This review article highlights fascinating examples of new physical behavior arising from the interplay of nematic molecular order and both chiral symmetry and topology of colloidal inclusions within the nematic host. Furthermore, the article concludes with a brief discussion of how these findings may lay the groundwork for new types of topology-dictated self-assembly in soft condensed matter leading to novel mesostructured composite materials, as well as for experimental insights into the pure-math aspects of low-dimensional topology.

Liquisolid Technique for Solubility Enhancement of Poorly Soluble Drug - A Brief Review.

Most of the newly discovered drug candidates are lipophilic and poorly water-soluble, making it a significant challenge for the pharmaceutical industry to formulate suitable drug delivery systems. This review gives insight into an overview of the liquisolid technique (LST) and summarizes the progress of its various applications in drug delivery. This novel technique involves converting liquid drugs or drugs in a liquid state (such as solutions, suspensions, or emulsions) into dry, nonadherent, free-flowing, and readily compressible powder mixtures by blending or spraying a liquid dispersion onto specific powder carriers and coating materials. In Liquisolid systems, the liquid medication is absorbed into the interior framework of carriers. Once the carrier's interior is saturated with liquid medication, a liquid layer forms on the surface of the carrier particles, which is instantly adsorbed by the fine coating material. As a result, a dry, free-flowing, and compressible powder mixture is formed. Compared to other solubility enhancement techniques, s.a. micronization, inclusion complexation, microencapsulation, nanosuspension, and self-nano emulsions, LST is relatively simple to prepare and may offer a cost-effective solution to enhance the solubility of poorly water-soluble drugs enhancing its bioavailability in drug formulation and delivery.

Process Intensification of Gas–Liquid Separations Using Packed Beds: A Review

The gas–liquid multiphase process plays a crucial role in the chemical industry, and the utilization of packed beds enhances separation efficiency by increasing the contact area and promoting effective gas–liquid interaction during the separation process. This paper primarily reviews the progress from fundamental research to practical application of gas–liquid multiphase processes in packed bed reactors, focusing on advancements in fluid mechanics (flow patterns, liquid holdup, and pressure drop) and the mechanisms governing gas–liquid interactions within these reactors. Firstly, we present an overview of recent developments in understanding gas–liquid flow patterns; subsequently we summarize liquid holdup and pressure drop characteristics within packed beds. Furthermore, we analyze the underlying mechanisms involved in bubble breakup and coalescence phenomena occurring during continuous flow of gas–liquid dispersions, providing insights for reactor design and operation strategies. Finally, we summarize applications of packed bed reactors in carbon dioxide absorption, chemical reactions, and wastewater treatment while offering future perspectives. These findings serve as valuable references for optimizing gas–liquid separation processes.

Nucleobase‐Driven Wearable Ionogel Electronics for Long‐Term Human Motion Detection and Electrophysiological Signal Monitoring

AbstractIonogels are considered as ideal candidates for constructing flexible electronics due to their superior electrical conductivity, flexibility, high thermal and electrochemical stability. However, it remains a great challenge to simultaneously achieve high sensitivity, repeated adhesion, good self‐healing, and biocompatibility through a straightforward strategy. Herein, inspired by nucleobase‐tackified strategy, a multifunctional adhesive ionogel is developed through one‐step radical polymerization of acrylated adenine/uracil (Aa/Ua) and acrylic acid (AA) monomers in sodium caseinate (SC) stabilized liquid metal dispersions. As a soft conductive filler, the incorporating of liquid metal not only improves the electrical conductivity, but also enhances the mechanical strength, satisfying the stretchable sensing application. The large amount of noncovalent interactions (hydrogen bonding, metal coordination, and ion‐dipole interactions) within the networks enable the ionogels to possess excellent stretchability, skin‐like softness, good self‐healing, and strong adhesion. Based on these desirable characteristics, the ionogel is suitable for wearable strain sensors to precisely detect diverse human movements under extreme environments. Moreover, the seamless adhesion with human skin allows the ionogel to function as bioelectrode patch for long‐term and high‐quality electrophysiological signal acquisition. This research provides a promising strategy for designing ionogels with tailored functionalities for wearable electronics that satisfy diverse application requirements.

On the transition of liquid dispersion states and their physical-thermodynamic nature in the development of gas-condensate reservoirs in depletion mode

While the depletion regime for gas-condensate fields may be more cost-effective, it often results in the loss of hydrocarbon condensate, which is economically more valuable than gas, and leads to the inefficient exploitation of the field in terms of condensate production. Therefore, the development of effective exploitation systems for such fields is essential. Effective exploitation of gas-condensate fields involves achieving maximum hydrocarbon condensate production in addition to maximum gas production. From this aspect, managing the condensate factor of reservoir system during the depletion regime is a critical issue. The article experimentally and theoretically investigates the phase transitions or mutual dispersion occurrences between hydrocarbon liquid and gas mixtures that occur with a decrease in pressure at reservoir temperature during the natural depletion of gas-condensate fields. During the exploitation of gas-condensate fields, it has been observed that even at pressures higher than retrograde condensation pressure, the hydrocarbon system undergoes complex phase transitions, resulting in distinct transition points due to the mutual dispersion of hydrocarbon liquid and gas. Additionally, pVT studies conducted in the laboratory have made it possible to determine the transition points of the reservoir fluid in the “liquid in gas” and vice versa dispersion states. The research has demonstrated that dependance of gas condensate factor on pressure under given isothermal natural conditions more clearly reflects the retrograde and maximum condensation, also dispersion points of the liquid components. It was found that proportionality coefficient between condensate ratio and pressure of gas-condensate system is unique for each production facility under isothermal conditions and characterizes the stability of fluid’s dispersion state. The importance of considering such transition points when designing gas-condensate field development projects has been highlighted.

On the transition of liquid dispersion states and their physical-thermodynamic nature in the development of gas-condensate reservoirs in depletion mode

This work presents new results of physical and chemical analysis of samples from contaminated areas of the Absheron field. The advantages and disadvantages of the used and traditional methods of cleaning oil waste are shown. Modern methods have been used to determine the characteristics of oil sludge samples from the Balakhany, Ramana, Surakhany, Bibiheybet fields of the Absheron Peninsula: oil sludge composition, viscosity, density, water content, chemical composition, temperature, cutting size, toxicity, volume, pH level, turbidity, BOD (biological oxygen demand), TDS (total dissolved solids). The main properties of oil sludge from the fields of the Absheron Peninsula are analyzed and compared. Chromatographic analysis (Agilent 7820A GC) allowed us to separate the oil waste and mixtures of the studied samples into individual compounds and components. The separation and determination of the components of the waste mixture by gas chromatography consisted of three stages: 1) Introduction of the sample into the chromatograph, 2) Separation of the sample into individual components, 3) Determination of the compounds contained in the sample. An inductively coupled plasma mass spectrometer (Agilent 7500 cs) with reaction cell was used for the efficient determination of trace heavy metals in petroleum waste. The ion lens unit used in the Agilent 7500cs provided high sensitivity measurements. Thus, trace metals were detected in the samples. A vacuum distiller (Retort Oil and Water Kit RROW-50) was used to quantify liquid and solids in drilling mud. Comparison of our oil sludge analysis results with field data demonstrates the effectiveness of these methods in identifying the composition of oil sludge for obtaining target products. From the studied wastes of the oil industry, it is possible to obtain special additives and use them, for example, for asphalt concrete. The dependences of oil sludge evaporation (of the Balakhany, Ramana, Surakhany, Bibieybet deposits) on air temperature and thermal resistance of the waterproofing material of the oil storage facility have been studied. The evaporation of components also depends on the concentration of oil sludge. Based on our sample analyses, it has been shown that the combined use of physicochemical and chemical methods makes it possible to purify oil sludge to acceptable limits. The dependences of oil evaporation on air temperature and the thermal resistance of the waterproofing material of an oil tank on the concentration of oil sludge have been established.

Explicit and approximate solutions for a classical hyperbolic fragmentation equation using a hybrid projected differential transform method

Population balance equations are widely used to study the evolution of aerosols, colloids, liquid–liquid dispersion, raindrop fragmentation, and pharmaceutical granulation. However, these equations are difficult to solve due to the complexity of the kernel structures and initial conditions. The hyperbolic fragmentation equation, in particular, is further complicated by the inclusion of double integrals. These challenges hinder the analytical solutions of number density functions for basic kernel classes with exponential initial distributions. To address these issues, this study introduces a new approach combining the projected differential transform method with Laplace transform and Padé approximants to solve the hyperbolic fragmentation equation. This method aims to provide accurate and efficient explicit solutions to this challenging problem. The approach's applicability is demonstrated through rigorous mathematical derivation and convergence analysis using the Banach contraction principle. Additionally, several numerical examples illustrate the accuracy and robustness of this new method. For the first time, new analytical solutions for number density functions are presented for various fragmentation kernels with gamma and other initial distributions. This method significantly enhances solution quality over extended periods using fewer terms in the truncated series. The solutions are compared and verified against the finite volume method and the homotopy perturbation method, showing that the coupled approach not only estimates number density functions accurately but also captures integral moments with high precision. This research advances computational methods for particle breakage phenomena, offering potential applications in various industrial processes and scientific disciplines.