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Modelling multiphase flow in fractured media is a challenging multi-disciplinary problem which is of particular importance for the production of hydrocarbons from unconventional geological formations. At the pore-scale, this can be studied using pore network models that are computationally efficient due to the employment of pore-space geometrical simplifications. There are two distinctive approaches to pore network modelling: quasi-static and dynamic. However, only dynamic pore network models allow capturing the transient nature of the multiphase flow. Nevertheless, the dynamic models have a number of limitations including numerical oscillations and the inability of interface tracking in a particular network element. In order to overcome these drawbacks, a hybrid numerical method which combines the Hagen–Poiseuille analytical solution of the Navier–Stokes equations and the volume of fluid advection scheme is developed and validated. The proposed multiphase model is benchmarked against the conventional volume of fluid implementation for various drainage and imbibition cases using two-dimensional demo cases. Besides, three-dimensional simulations are also performed to ensure the applicability of the proposed model to real fractured media. The single pressure algorithm is employed while the capillary pressure drop is explicitly introduced as an additional term in the Hagen–Poiseuille equation. The conducted validation and following analysis show the applicability of the developed model for a wide range of Reynolds and capillary numbers and viscosity ratio. Thus, the new model can be used to investigate transient immiscible multiphase flow phenomena in fractures by pore network modelling. • PNM and VOF methods are coupled to simulate multiphase flow in fractures. • The model is validated against conventional volume of fluid solver. • Computational time of the method is considerably lower than VOF realisation. • The model captures multiphase flow physics in complex 3D fracture networks. [ABSTRACT FROM AUTHOR]

Polyglycerol-polyricinoleate (PGPR) and curcumin were added to canola oil in order to evaluate the effects of PGPR on the interfacial performance of curcumin. A combination-model (linear-sigmoidal) was employed for measuring kinetic-indices relevant to the initiation and propagation phases during the peroxidation process. In the presence of curcumin (4.343 mM), the rate constants of formation and decomposition of hydroperoxides (ROOHs) were 2.94 × 10−5 meq.kg and 6.1 × 10−3 min−1, respectively, which significantly decreased compared to the control sample. The antioxidant activity of curcumin (1.086 mM) was 2.07, which increased in the presence of PGPR (2.72). This enhancement was due to a decrease in the participation rate of curcumin molecule (AH) in an undesirable chain-initiation reaction, i.e. AH + ROOH→A●+RO●+H 2 O. In addition, an analysis of rate equations showed that the electron-transfer mechanism of curcumin was modified in the presence of PGPR, so that the rate of participation was reduced to zero in the undesirable reaction, i.e. A●+RH→AH + R●. • Antioxidant activity of curcumin was affected by its interfacial performance. • PGPR, as a surfactant, remarkably increased the interfacial activity of curcumin. • PGPR promoted the interactions between the free radicals and curcumin molecules. • Curcumin participation in side reactions was stopped in the presence of PGPR. [ABSTRACT FROM AUTHOR]

The interfacial and temperature behavior of water, n-decane, decanol, poly(dimethylsiloxane) (PDMS) bound to nanooxides initial or after high-pressure cryogelation and silica gels was analyzed using low-temperature 1H NMR spectroscopy (applied to static samples to observe only mobile adsorbates), differential scanning calorimetry (DSC), thermoporometry and quantum chemical methods. Both NMR and DSC results demonstrated that during heating of frozen samples a fraction of organics or PDMS remained frozen at temperature higher than the melting point of bulk liquid and a fraction of any adsorbate remained unfrozen upon cooling at temperature lower than the freezing point. These effects depend on the type of an adsorbate and the pore sizes of an adsorbent. Broadening of freezing/melting temperature range is observed for PDMS or decane confined in pores of silica gel or voids between nanoparticles in fumed nanooxides. This effect is minimal for silica gel Si-100 with broad mesopores. [ABSTRACT FROM AUTHOR]

Abstract: Understanding and control of interfacial phenomena between electrode material and liquid electrolytes are of major scientific importance for boosting development of high-performance lithium ion batteries with reliable electrochemical/safety attributes. Here, as an innovative surface engineering approach to address the interfacial issues, a new concept of mixed ion/electron-conductive soft nanomatter-based conformal surface modification of the cathode material is presented. The soft nanomatter is comprised of an electron conductive carbonaceous (C) substance embedded in an ion conductive polyimide (PI) nanothin compliant film. In addition to its structural uniqueness, the newly proposed surface modification benefits from a simple fabrication process. The PI/carbon soft nanomatter is directly synthesized on LiCoO2 surface via one-pot thermal treatment of polyamic acid (=PI precursor) and sucrose (=carbon source) mixture, where the LiCoO2 powders are chosen as a model system to explore the feasibility of this surface engineering strategy. The resulting PI/carbon coating layer facilitates electronic conduction and also suppresses unwanted side reactions arising from the cathode material-liquid electrolyte interface. These synergistic coating effects of the multifunctional PI/carbon soft nanomatter significantly improve high-voltage cell performance and also mitigate interfacial exothermic reaction between cathode material and liquid electrolyte. [Copyright &y& Elsevier]

Complex transition metal oxides have played a central role in the study of magnetic materials, serving as model systems for explorations of fundamental exchange interactions and the relationships between structural, electronic, and magnetic responses. Enabled by advances in epitaxial synthesis techniques, abrupt heterointerfaces and superlattices have emerged as a powerful platform for engineering novel magnetic behavior in oxides. Following a brief introduction to the dominant exchange mechanisms in metal oxides, we review the general means by which interfacial magnetism can be tailored in ABO3 perovskites, including interfacial charge transfer, epitaxial strain and structural coupling, orbital polarizations and reconstructions, and tailoring exchange interactions via cation ordering. Recent examples are provided to illustrate how these strategies have been employed at isolated interfaces and in short-period superlattices. We conclude by briefly discussing underexplored and emerging research directions in the field. [ABSTRACT FROM AUTHOR]

Abstract: The design of contact apparatuses in which one liquid phase is dispersed into another is a challenging task with regard to fluid dynamics and mass transfer. To disentangle the complexity in these multiphase polydispersed systems with all their coupled mutual interactions, one first step towards a reliable prediction is to reduce the system to a single droplet problem, where a single droplet is moving in a quiescent ambient phase. Commonly, one is interested in the mass transfer coefficient (or Sherwood number) in case of the transfer of a soluble component, and the drop velocity of fall/rise. In order to save time and money, one objective is to predict the behaviour of a given system as reliable as possible to minimise the own experimental (and numerical) effort. However, although the issue is “only” to understand the single droplet, merely in a few basic cases analytical equations are available and applicable, and results based on CFD methods have to be judged with care. Additionally, in most cases experimental or numerical data for a given system may not be available at all, hence the practitioner has to select the best suitable empirical or semi-empirical approaches for the corresponding system which itself is a challenging task. This paper aims to help to make the required decisions and to enable the reader to characterise and confine a given extraction system regarding fluid dynamics and mass transfer. Thereto, a chart is presented to initiate a selection process starting from simpler cases to cases with increasing complexity, especially addressing the behaviour of systems dominated by Marangoni instabilities. [Copyright &y& Elsevier]

Highlights: [•] An absorber packed closely with cylindrical packing was designed in this study. [•] The wetting of packing surface is a key factor for absorber performance. [•] The Marangoni effect can be triggered in the system with continuous liquid phase. [•] The surface stress increases significantly as TEG concentration exceeds 92wt.%. [•] The larger flow rate of TEG solution weakened the Marangoni effect. [ABSTRACT FROM AUTHOR]

Abstract: This paper summarizes the bi-metallic experiments using a high-vacuum test apparatus to understand the interfacial phenomena between Mg (AM60) and Al (A390) samples. The test results show significantly improved wetting and metallurgical bonding between the molten magnesium and aluminum substrate when a “zincate+galvanizing” surface treatment was applied. This surface treatment removes the intrinsic Al2O3 layer on the aluminum substrate and, in turn, forms a very thin metallic zinc film on the substrate. Interfacial reactions between the aluminum substrate and the molten magnesium led to the improved metallurgical bonding and significantly improved shear strength in the bi-metallic samples with “zincate+galvanizing” surface treatment. However, long reaction times led to the formation of excessive intermetallic compounds at the interface, which reduced bond strength. [Copyright &y& Elsevier]

Fluid manipulations at the microscale and beyond are powerfully enabled through the use of 10-1,000-MHz acoustic waves. A superior alternative in many cases to other microfluidic actuation techniques, such high-frequency acoustics is almost universally produced by surface acoustic wave devices that employ electromechanical transduction in wafer-scale or thin-film piezoelectric media to generate the kinetic energy needed to transport and manipulate fluids placed in adjacent microfluidic structures. These waves are responsible for a diverse range of complex fluid transport phenomena-from interfacial fluid vibration and drop and confined fluid transport to jetting and atomization-underlying a flourishing research literature spanning fundamental fluid physics to chip-scale engineering applications. We highlight some of this literature to provide the reader with a historical basis, routes for more detailed study, and an impression of the field's future directions. [ABSTRACT FROM AUTHOR]

A model of electro-magneto-thermo-mechanics for electroconducting polarized nonferromagnetic medium is proposed which takes into account the local mass displacement in addition to the local electric charge displacement. The corresponding key set of equations is written. Using the isothermal approximation, the model is applied to describe the interface inhomogeneity of a stressed state, the polarization and coupled electric charge in thin dielectric films. An anomalous dependence of the electric capacity on the thickness of a thin dielectric film, observed experimentally by Mead, is also studied and is shown to be well captured by the present approach.

• A comprehensive description of the phenomena at the Ni steel/corundum interface. • Carbon content influences the degree of interaction at the phase interface. • Erosion in the corundum surface layer accompanied by the formation of new phases. • Redistribution of calcium and silicon in the surface layer to a depth of 140 µm. A comprehensive description of the phenomena at the low-alloy Fe-C-O-Ni steel/corundum interface at elevated temperatures up to 1600 °C was performed using the sessile drop method, Differential Thermal Analysis (DTA), 3D Differential Scanning Calorimetry (3D DSC) as well as several supporting methods, namely Energy Dispersive X-Ray (EDX), X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy (SEM). Steel samples with different carbon (0.04–1.56 wt%) and nickel (1.08–4.48 wt%) contents were selected to assess the effect of temperature and chemical composition on the related quantities, namely density, surface and interfacial tension, wetting angles, and the work of adhesion. While increased nickel content caused a decrease in wetting angle, and surface and interfacial tension values, the increased carbon content had the opposite effect. Two distinctly different modes of high-temperature interaction at the phase interface were also described. Little interaction was observed between the steel with lower carbon content (<0.1 wt%) and the corundum substrate. On the contrary, a more substantial interaction occurred in steel with higher carbon content and thus lower liquidus temperature. There was significant disruption of the corundum substrate at the surface and in depth up to 140 µm. The original corundum structure was replaced by new structural phases, particularly hibonite, grossite and gehlenite. In addition, when a higher chromium content was present in the steel, chromium-doped corundum was formed. [ABSTRACT FROM AUTHOR]

Replica exchange molecular dynamics were used to observe the adsorption of single-stranded DNA (ssDNA) onto the surface of single-walled carbon nanotubes (SWCNTs). The assembly of these systems has garnered interest as a method by which SWCNTs can be separated based on chirality. While the exact mechanism of separation is yet unknown, it is hypothesized that the structure of the ssDNA layer pays an important role. Characterization of such an adsorbed layer has been a matter of recent work with the focus being on atomic level detail or such as base-stacking and hydrogen bonding. In this manuscript, we detail a new observation of ssDNA organization and demonstrate how it can be used to infer additional information about the way in which such biopolymers wrap around the cylindrical SWCNT. [Display omitted] • Replica exchange simulations are used to assembled ssDNA oligomers on SWCNT surfaces. • Assembly is effected by underlying carbon surface as determined by density plots. • Wrapping angles of ssDNA on SWCNTs can be predicted using geometric relationships. [ABSTRACT FROM AUTHOR]

• Surface-functionalized silica nanoparticles have excellent water-wetness properties. • Surface-functionalized silica nanoparticles have the ability to serve as highly efficient Pickering emulsifiers. • Surface-functionalized silica nanoparticles do not necessarily change the IFT in a water-n-octane system. Due to their unique properties, nanoparticles have recently attracted lots of attention for enhanced oil recovery (EOR) and CO 2 geo-sequestration (CGS) applications. The purpose of this research is to offer a better understanding of the role of nanoparticles on interfacial phenomena with a special focus on wettability alteration, interfacial tension and emulsification characteristics. Contact angle measurements were used to explore the effect of nanoparticles on wettability alteration of glass surfaces using sessile drop method in the absence and presence of NaCl. Scanning electron microscopy (SEM) images were collected to visualize how nanoparticles change the wettability of the surfaces. The effect of different parameters on morphology variation of glass surfaces and the consequent wettability alteration was examined. The investigated variables were nanoparticle concentration, exposure time, measurement time and salinity. Next, the effect of nanoparticles on interfacial tension (IFT) between water and n-octane was studied via the Wilhelmy plate method. The effect of nanoparticle concentration on IFT was investigated with and without added NaCl. Finally, a series of simple batch experiments were conducted to observe the effect of nanoparticles in emulsification behavior of a water-n-octane system. Photography and optical microscopy images were collected to analyze the stability and morphology of the formed emulsions for different nanoparticle concentrations in the absence and presence of NaCl. Our results show that the EOR-12 nanoparticles have excellent water-wetness properties and emulsification characteristics but do not necessarily change the IFT in a water-n-octane system. micrographs taken from the nanofluid-treated glass surfaces showed a thick coverage of nanoparticles confirming the adsorption of nanoparticles onto the surface. Additionally, SEM images revealed a topography change of surfaces from smooth to rough after treatment with nanofluid which is the responsible mechanism for the observed wettability alteration. The higher the exposure time, the rougher the nanoparticle adsorption layer and consequently the better the performance of nanoparticles in wettability alteration of glass surfaces. Additionally, up to a threshold concentration, the contact angle decreased as the nanoparticle concentration increased, but above the threshold concentration, the measured contact angle did not show remarkable reduction. Conducting contact angle measurements in the presence of NaCl demonstrated that salinity can increase the adsorption rate, the final number of nanoparticles on the glass surface, the surface roughness and the intrinsic contact angle of nanoparticles leading to a better water-wetness. Testing different concentration of nanoparticles demonstrated that in the presence of NaCl, the wettability of the glass surface was not affected by the concentration and low concentrations of nanoparticles act as good as high concentrations. IFT measurements did not show any significant reduction in IFT between water and n-octane for all the tested concentrations with and without added NaCl mainly because of lack of the energy required to bring the nanoparticles at the interface. The results of batch emulsification experiments revealed that EOR-12 nanoparticles could serve as highly efficient Pickering emulsifiers in terms of both initial emulsion volume and its stability over time with and without NaCl. Adsorption of the nanoparticles at the interface was identified as the underlying mechanism for the emulsification characteristics of the nanoparticles. Photographs and optical microscopy measurement results illustrated that by tuning the nanoparticle concentration, emulsion droplet size and its uniformity can be adjusted. By utilizing higher concentrations of nanofluid, emulsions with smaller and more uniform droplet size and higher stability can be created. [ABSTRACT FROM AUTHOR]

Cold-sprayed Cu coatings are known to have low ductility as the microstructure is composed of dynamically recrystallized fine grains, as well as larger crystals with high dislocation density. Annealing is typically employed to restore the ductility of the Cu coating to form larger crystals with low dislocation density; however, the influence of annealing on the microstructure and chemistry of the particle-particle interfaces (PPIs) have yet to be explored in great detail. Here, we report the structural evolution of PPI after annealing treatments. Nanoscale pores at the PPI can be effectively reduced by annealing and the trapped oxide films in the as-sprayed coatings break up and coarsen following classical interfacial phenomena. As a result, metallurgical bonding between particles increased significantly, contributing to the enhanced ductility of the cold-sprayed Cu coating. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] Effects of pressure and concentration on characteristics of silica cryogels. [•] Confined space effects on the interfacial behavior of water bound to cryosilicas. [•] Effects of cryosilica structure on co-adsorption of water with organics and inorganics. [ABSTRACT FROM AUTHOR]

Highlights: [•] The porosity of resins and chars increases with increasing water content on polymerization. [•] Water blocks narrow pore entrance in chars reducing organics adsorption. [•] NMR cryoporometry is an effective tool to study the adsorbent porosity in liquid media. [Copyright &y& Elsevier]

We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force-distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin-Landau-Verwey-Overbeek theory with an additive repulsive steric (entropic) ion-surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Ous clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high-free-ion density ionic liquids and ionic liquid blends. [ABSTRACT FROM AUTHOR]

Abstract: Water management is an important issue in the polymer electrolyte membrane (PEM) fuel cell, which is considered as a promising alternative power source for future automotive applications. In this article, lattice Boltzmann simulations are conducted to examine the interfacial phenomena in liquid water transport in porous materials of a PEM fuel cell. Numerical results clearly indicate that large perforated pores through the porous diffusion layers can serve as a convenient liquid water transport pathway and thus assist in liquid water removal. An interconnected horizontal and vertical pore combination is especially beneficial to liquid water transport through the porous layers in flooding conditions. Therefore, liquid water transport in a PEM fuel cell may be effectively managed through well engineered interfacial structures in porous materials. [Copyright &y& Elsevier]

With an aim to recycle waste polymers as a carbon resource in steelmaking, in-depth investigations have been carried out on polymer/coke blends and molten steel at 1823 K. Three polymers, namely high density polyethylene (HDPE), polyethylene terephthalate (PET), and bakelite were blended with metallurgical coke and devolatilized at 1473 K using a drop tube furnace. High temperature interactions of various chars with molten steel were investigated at 1823 K using the sessile drop technique in argon atmosphere; the influence of polymers on the interfacial phenomena and carbon dissolution was determined. While the residual volatiles from HDPE did not affect the chemical composition of interfacial products, the coverage of the interfacial region was somewhat slower than metallurgical coke. Oxygen present in PET was found to oxidize liquid steel leading to the formation of FeO at the interface modifying both the chemical composition and the morphology of the interfacial region. CaCO3, present as a filler impurity in bakelite was found to act as a fluxing agent and lowered the melting point of the ash layer at the metal/carbon interface. The addition of polymers improved the overall carbon dissolution into molten steel by a small extent as compared to metallurgical coke. This study has shown that a variety of waste polymers can be utilized to partially replace metallurgical coke in steelmaking. [ABSTRACT FROM AUTHOR]

Abstract: The interfacial behavior of silicone oils Oxane 1000 and Oxane 5700 (polydimethylsiloxanes, PDMS) interacting with dried or hydrated (hydration h =0.005 or 0.1g/g) silica gels Si-60 and Si-100 or nanosilica A-400 was studied using low-temperature 1H NMR spectroscopy over the 210–310K range. Broadening of the melting temperature range toward both sides from the freezing point is observed for silicone oils confined in mesopores (2–15nm in radius) of silica gel particles (0.2–0.5mm in size) or voids (1–100nm) between silica nanoparticles (5–10nm in size) in their aggregates. This effect is a consequence of the phase state heterogeneity, since both liquid and solid-like fractions of adsorbed PDMS are observed over a large temperature range. The adsorbed PDMS heterogeneity depends on the pore size distribution (confined space effect), and it is lower for silica gel Si-100 possessing broader pores than Si-60. An increase in the amounts of adsorbed polymer and water diminishes the effects of confined space on PDMS because a fraction of the polymers is located in broader pores or out of pores (voids). This leads to relative decrease in interactions of PDMS with the silica surface. 1H NMR spectra of PDMS and n-decane bound to silica gels reveal much stronger heterogenization of adsorbed PDMS (depending on the polymer length) than that of the alkane. [Copyright &y& Elsevier]

Abstract: Solutions (Or), along the de-mixing line in the system water/benzene/ethanol were contacted with water (W) and the spontaneous emulsification followed by a camera at 40pictures/s. The emulsions formed predominantly in the solution layer for both the aqueous and organic branch of the de-mixing line. These results were projected on the phase diagram of the system and a direct relationship between diagram features and the mechanism of spontaneous emulsification showing a significantly more powerful reaction for solutions of a composition close to the plait point of the system. [Copyright &y& Elsevier]

Abstract: The electroreduction of nitrogen species in alkaline medium was performed on platinum nanoparticles (1–2nm) with metal loadings of 5 and 10wt% Pt, synthesized by the chemical carbonyl route. The electrochemically active surface analysis evidences that the real surface area is concomitant to the Pt-loading in the support. The electrochemical analysis put in evidence that nitrite ions were reduced from −0.6 to −0.78V and the charge transfer step is attributed to the NO2 −/NO redox couple. The Tafel slope analysis confirms that from E p to −0.78V the reduction of NO occurs via an ECE mechanism. An analysis of Nicholson–Shain schemes and NO-saturated in solution verified these results. [Copyright &y& Elsevier]

Abstract: Experimental results on polymer, protein, and composite cryogels and data treatment methods used for morphological, textural, structural, adsorption and diffusion characterisation of the materials are analysed and compared. Treatment of microscopic images with specific software gives quantitative structural information on both native cryogels and freeze-dried materials that is useful to analyse the drying effects on their structure. A combination of cryoporometry, relaxometry, thermoporometry, small angle X-ray scattering (SAXS), equilibrium and kinetic adsorption of low and high-molecular weight compounds, diffusion breakthrough of macromolecules within macroporous cryogel membranes, studying interactions of cells with cryogels provides a consistent and comprehensive picture of textural, structural and adsorption properties of a variety of cryogels. This analysis allows us to establish certain regularities in the cryogel properties related to narrow (diameter 0.4< d <2nm), middle (2< d <50nm) and broad (50< d <100nm) nanopores, micropores (100nm< d <100μm) and macropores (d >100μm) with boundary sizes within modified life science pore classification. Particular attention is paid to water bound in cryogels in native superhydrated or freeze-dried states. At least, five states of water — free unbound, weakly bound (changes in the Gibbs free energy−ΔG <0.5–0.8kJ/mol) and strongly bound (−ΔG >0.8kJ/mol), and weakly associated (chemical shift of the proton resonance δH =1–2ppm) and strongly associated (δH =3–6ppm) waters can be distinguished in hydrated cryogels using 1H NMR, DSC, TSDC, TG and other methods. Different software for image treatment or developed to analyse the data obtained with the adsorption, diffusion, SAXS, cryoporometry and thermoporometry methods and based on regularisation algorithms is analysed and used for the quantitative morphological, structural and adsorption characterisation of individual and composite cryogels, including polymers filled with solid nano- or microparticles. [Copyright &y& Elsevier]

Various interfacial emergent phenomena have been discovered in tunable nanoscale materials, especially in artificially designed epitaxial superlattices. In conjunction, the atomically fabricated superlattices have exhibited a plethora of exceptional properties compared to either bulk materials separately. Here, the (CrO 2 ) m /(TaO 2 ) n superlattices composed of two lattice-matched metallic metal oxides are constructed. With the help of first-principle density-functional theory calculations, a computational and theoretical study of (CrO 2 ) m /(TaO 2 ) n superlattices manifests the interfacial electronic properties in detail. The results suggest that emergent properties result from the charge transfer from the TaO 2 to CrO 2 layers. At two special ratios of1:1and1:2between m and n , the superlattices undergo metal-to-insulator transition. Additionally, the bands below the Fermi level become narrower with the increasing thickness of the CrO 2 and TaO 2 layers. The study reveals that the electronic reconstruction at the interface of two metallic materials can generate interesting physics, which points the direction for the manipulation of functionalities in artificial superlattices or heterostructures within a few atomic layers., (© 2022 IOP Publishing Ltd.)

Abstract: Various applications of magnetic fluids involve interface phenomena. The analysis of the hydrostatic interface shape between two immiscible liquid layers, especially under magnetic field influence, is the first step to understand the accompanying complex dynamic phenomena as well as to providing reliable numerical capabilities for their accurate prediction. This study presents a relatively simple numerical approach, and the accompanying theory, to reliably define the meniscus shape in a two-layered fluid system in presence of a horizontal magnetic field with a vertical gradient. In the course of the study, two dimensionless parameters have been derived to describe the magnetic pressure jump at the interface and the magnetic body force throughout the volume. These parameters are used to interpret the results of the analysis and to show that a horizontal magnetic field tends to flatten the meniscus shape at the interface despite of the direction of its vertical gradient. [Copyright &y& Elsevier]

An in-depth wettability and interfacial phenomena investigation was carried out to study interactions between high density polyethylene (HDPE) and petroleum coke. The aim is to investigate the effect of temperature and contact times on possible interactions and adhesion characteristics for partially substituting coal-tar pitch binder with waste polymers. Using a sessile drop arrangement, experimental assemblies consisting of ground HDPE and a petroleum coke substrate were heat treated in the temperature range of 150-350°C for 15-60 min. Contact angles between molten HDPE and petroleum coke surface and depth of penetration of HDPE into petroleum coke substrate were measured. The highest contact angle (131.5°) was observed at 250°C after 15 min. and lowest contact angle (30.9°) was observed at 350°C after 60 min. Highest penetration depth (75 μm) was observed at 350°C after 60 min and lowest penetration (13 μm) at 200°C after 15 min. Analysis of results showed that increasing time and temperature of heat treatment had a significant impact on the interactions of molten HDPE with petroleum coke. Longer residence time and higher temperatures increased the extent of melting of HDPE, which in turn resulted in improved wettability and deeper penetration into petroleum coke substrate. HDPE was found to bind and adhere strongly with petroleum coke. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

The effect of Al2O3 and MgO on the interfacial tension between the molten CaO-SiO2-based slag and solid steel at 1773 K was studied. The interfacial tension of molten slags slightly increased with increasing Al2O3, but no significant change of interfacial tension was observed with higher MgO. Fourier transform infrared (FTIR) of as-quenched slag samples indicated the slag structure to polymerize with Al2O3 additions, but depolymerize with MgO additions. Further detailed studies of the slag surface using X-ray photoelectron spectroscopy (XPS) showed the fraction of free oxygen ions to decrease with higher Al2O3 but remained constant at higher MgO. The results suggested that interfacial tension decreases not only with the depolymerization of the melt, but also with an increase in the free oxygen ions at the molten slag/solid steel interface. [ABSTRACT FROM AUTHOR]

Experimental study on the dynamic behaviour of magnetic levitating magnet-magnetic fluid element in the external alternating magnetic field is described. Two types of element motions occur according to the magnetic field strength and frequency of the external alternating magnetic field. Seesaw motions of the element and harmonic motions of magnetic fluid surface are observed using high-speed video camera system. Transient phenomena in element response and the change of spikes pattern on the magnetic fluid surface are revealed. [ABSTRACT FROM AUTHOR]

The intrinsic property of liquids is a vital indicator of formulation performance and stability. Therefore, investigation of the interfacial phenomenon of surface tension is a routine procedure in the development of products in a wide variety of areas including foods, pharmaceuticals, cosmetics, and painting technologies. We hypothesize that studies related to the maximum pull on a rod can be extrapolated to disk geometry and applied to measure surface tension using a texture analyzer. A glass disk probe was attached to the arm of a texture analyzer and pulled from the liquid surface. The maximum force of detachment was used to calculate surface tension extrapolating from the theory of maximum pull on a rod. The surface tension of water, ethanol, and a hydroalcoholic solution was measured and compared with literature values to validate this hypothesis. The calculated values of surface tension for the liquids studied were within 5% of the reported values. Probe diameter appears to have an important role on surface tension accuracy compared with literature values. Slight discrepancies can be attributed to temperature control and leveling of liquid surface, although still in accordance with the reported values of surface tension measured using different methods. This study presents a simple, precise, and quick method to determine the surface tension of liquids from the maximum pull on a disk. Further studies are warranted to determine the optimum glass disk probe diameter for better accuracy. [ABSTRACT FROM AUTHOR]

Abstract: Low-temperature 1Н NMR spectroscopy was used to study states of water bound to phosphoric and phosphonic acids (phosporus oxyacids, POA) alone or adsorbed onto nanosilica OX-50 (specific surface area S BET =52m2/g) or A-300 (S BET =297m2/g). Concentrated solutions or weakly hydrated solid POA or dried silica/POA powders placed in CCl4 medium are characterized by different temperature dependences of the chemical shift of the proton resonance (δ H) because of partial dissociation of PO–H bonds strongly affected by water amounts and temperature. NMR cryoporometry results show that both small water clusters and nanodomains are present at the interfaces of hydrated solid POA and silica/POA powders. Quantum chemical calculations of the 1H NMR spectra demonstrate the influence of POA/water cluster structure and dissociation of the PO–H bonds on the δ H values. [Copyright &y& Elsevier]

Abstract: Interfacial phenomena involved in the underpotential deposition of tellurium layers were studied with an electrochemical quartz crystal nanobalance (EQCN) in perchloric acid solution (pH=1). The in situ study of the oxidation kinetics showed that the oxidation of the Te layer deposited neighbor a Teads/Au provides evidence of TeO2ads formation with the incorporation of oxygen to induce the formation of H2TeO3. From the calculations of the first tellurium layer (82ngcm−2), the mass expected for the second layer deposited in underpotential control was found. Moreover, the oxidation of Teads followed a bi-functional mechanism involving the oxygen incorporated before the tellurium oxidation at high overpotentials. The combination of powerful interfacial methods (cyclic voltammetry and EQCN) gives a new perspective on tellurium electrodeposition and leads to a comprehensive understanding of the interfacial architecture. [Copyright &y& Elsevier]

Abstract: Low-temperature 1H NMR spectroscopy was used to study water and concentrated hydrochloric acid solution clustered at a surface of silica A-300 initial and mechanochemically activated (MCA) with the bulk density ρ b =0.045 and 0.394g/cm3, respectively. Hydrochloric acid solution in contact with silica powder placed in nonpolar (CCl4) or weakly polar (CDCl3) media forms clusters of two types (with different content of HCl and water) in interparticle voids in aggregates of silica nanoparticles. This differentiation is stronger in the system with MCA silica because of enhanced confinement effects in narrower pores (voids) between adjacent nonporous nanoparticles. Obtained results are of importance for deeper insight into the mechanism of the influence of nanosilica used as an oral sorbent on the gastric juice properties. [Copyright &y& Elsevier]

Heat transport in boiling is governed by interfacial activity at dynamic gas-liquid-solid boundaries: the liquid-solid interface prognosticates wetting and nucleation of embryonic vapor bubbles, and the evolving liquid-vapor interface of bubbles affects dynamic surface tension, Marangoni convection, and the post-nucleation ebullient dynamics. at the micro-scale in this process, the transient transport mechanisms at the solid-liquid-vapor interfaces during nucleation and subsequent vapor-bubble-growth dynamics (which essentially characterize macro-scale heat transport and the ebullient signature of boiling), can be altered by introducing small quantities of surface-active additives (reagents or polymers) in a pure liquid (water). The molecular characteristics of reagents affect and control this process; in fact, surface wetting and surface tension can be decoupled. This review delineates those aspects of micro-scale interfacial changes that are essentially caused at a molecular-scale by the relative adsorption-desorption of reagents at the liquid-vapor interface, and their physisorption and electrokinetics at the liquid-solid interface. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the dynamics of the air cavity created by water entry of magnet-magnetic fluid projectile. The impact of a projectile, permanent magnet coated with kerosene-based magnetic fluid, on the free surface of water is investigated experimentally. The cavity of air in water created by the impact of the projectile is observed with the high-speed video camera system. Effects of the adsorption of magnetic fluid and alternating magnetic fields are revealed. [Copyright &y& Elsevier]

Metal separation by solvent extraction in macroscopic oil/water systems, is a major operation in several countries. Many studies have been devoted to the design of extractants to target specific metals and the use of additives such as modifiers, surfactants, and a second extractant for better kinetics, ease of processing, improved selectivity, and enhanced interfacial properties in these separation systems. As these are quite complex systems, both experimental and modelling studies can be very difficult. This is especially true when attempting to measure interfacial properties. However, over the years many novel pieces of equipment and experimental techniques have been developed to probe these multicomponent systems. This review investigates the role of additives in solvent extraction for metal separations in macroscopic oil/water systems. [ABSTRACT FROM AUTHOR]

Abstract: Using quantum electrochemical/thermodynamical approaches based on coupled cluster/polarized continuum models and density functional theory (CM/PCM–DFT), we investigated the corrosion inhibition mechanism of Al/NaOH system in the presence of some p-phenol derivatives. The influencing parameters on inhibitory action, i.e. charges on oxygen and hydrogen atoms of hydroxyl group, charge transfer, interaction energy, molecular activity and softness, electric dipole moment and de-solvation free energy, were determined for both neutral and deprotonated species at metal|solution interface. A good correlation was observed between these parameters and inhibition efficiency data reported in the literature. By introducing an appropriate thermodynamic procedure, we also determined the proton-loss tendency of the molecules nearby interface. The results were amazing and revealed a complicated protonation/deprotonation cycle for inhibitor species inside electrical double layer; the corrosive agents in the vicinity of metal surface become locally neutralized and pushed away. [Copyright &y& Elsevier]