Immiscible Components Research Articles

Role of emollients in the prevention of skin diseases in young children

Epidermis plays an important role in protecting the body from negative environmental influences. The horny layer plays a special role in carrying out these functions. Skin defense mechanisms are multistage and include 5 protective barriers responsible for maintaining the integrity and performing the main functions of the skin. The first one is a microbial barrier – determined by commensal flora which prevents contamination of pathogenic microorganisms; the second one is a physical barrier preventing mechanical skin damage, penetration of allergens and microorganisms; the third one is a chemical barrier achieved by forming pH and components of natural moisturizing factor as well as epidermal lipids; the fourth one – immune barrier – Langerhans cells, tissue basophils, lymphocytes etc.;the fifth is the neurosensory barrier – numerous nerve endings transmitting signals of skin integrity damage and controlling metabolic processes and homeostasis maintenance. Epidermal barrier of newborns and infants is imperfect and differs in its structure and functional activity from that of adults. Children’s skin is prone to excessive dryness, irritation, allergic reactions and inflammation. For young children, it is very important to minimize the risk of these manifestations. Individual selection and use of emollients in the basic care of infants promotes the functional stability of five protective «frontiers» of the epidermal barrier: prevents skin damage when exposed to unfavorable environmental factors, reduces TEWL, supports the normal microbiome, has antipruritic and anti-inflammatory action. Modern emollients restore the hydrolipidic layer of the epidermis and prevent the development of dermatitis and skin infection in children. An important role when choosing an emollient is played by its texture, which can be represented by a lotion, cream, balm, ointment. Chemically, creams, lotions and balms are emulsions, i.e. they consist of two immiscible components – fat (oil) and water. In this case, one of the components is in the other in the form of tiny droplets. Most skin diseases faced by young children are related to the integrity of the epidermis, which is why daily care should be primarily focused on protecting the skin barrier

Superior hygrothermal resistance and interfacial adhesion by ternary thermoplastic polymer blend matrix for carbon fiber composite

Carbon fiber reinforced thermoplastics (CFRTPs) with superior mechanical properties and hygrothermal resistance were fabricated using a strategically designed ternary polymer blend of polyamide 6 (PA6), polyethylene terephthalate (PET), and phenol novolac (PN). The polymer blend was designed to improve the hygrothermal stability of PA6 while retaining good adhesivity to carbon fiber. The miscible and immiscible components in the blend (PN and PET, respectively) have different contributions that act cooperatively to improve the hygrothermal resistance of PA6. The interfacial strength between the ternary polymer blend and carbon fiber is as high as that for PA6 because all components in the polymer matrix include polar functional groups. CFRTPs having the ternary blend as the polymer matrix exhibit superior stiffness under hygrothermal conditions than a conventional PA6-matrix CFRTP.

Simulation and preliminary validation of a three-phase flow model with energy

This paper is devoted to the simulation of the three-phase flow model [20], in order to account for immiscible components. The whole model is first recalled, and the main properties of the closed set are given, with particular focus on the Riemann problem associated with the convective subset that contains non-conservative terms, and also on the relaxation process. The model is hyperbolic, far from resonance occurrence, and a physically relevant entropy inequality holds for smooth solutions of the whole system. Owing to the uniqueness of jump conditions, specific solutions of the one-dimensional Riemann problem can be built, and these are useful (and mandatory) for the verification procedure. The fractional step method proposed herein complies with the continuous entropy inequality, and implicit schemes that are considered to account for relaxation terms take their roots on the true relaxation process. Once verification tests have been achieved, focus is given on the simulation of the experimental setup [8, 9], in order to simulate a cloud of droplets that is hit by an incoming gas shock-wave. Finally, the study of a three-phase flow setup involving thermal effects is presented, it is based on the KROTOS experiment [25] which focuses on vapour explosion simulation.

A four-field three-phase flow model with both miscible and immiscible components

A three-phase flow model with hybrid miscibility constraints is proposed: three immiscible phases are considered (liquid water, liquid metal and gas) but the gaseous phase is composed with two miscible components (steam water and non-condensable gas). The modelling approach is based on the building of an entropy inequality for the system of partial differential equations: once an interfacial velocity is given by the user, the model is uniquely defined, up to some relaxation time scales, and source terms complying with the second principle of thermodynamics can then be provided. The convective part of the system is hyperbolic when fulfilling a non-resonance condition and classical properties are studied (Riemann invariants, symmetrization). A key property is that the system possesses uniquely defined jump conditions. Last, preservation of thermodynamically admissible states and pressure relaxation are investigated.

Mixing of Immiscible Components by the Size Effect: A Case Study of Au–Ni Nanostructures

Modern catalysts widely utilize multicomponent nanosized materials and structures, and the interphase interactions in such systems are still unresolved in many aspects. In this work, we present the...

Construction of Natural Loofah/Poly(vinylidene fluoride) Core-Shell Electrospun Nanofibers via a Controllable Janus Nozzle for Switchable Oil-Water Separation.

Developing microstructure and multifunctional membranes toward switchable oil-water separation has been highly desired in oily wastewater treatment. Herein, a controllable Janus nozzle was employed to innovatively electrospin natural loofah/poly(vinylidene fluoride) (PVDF) nanofibers with a core-shell structure for gravity-driven water purification. By adjusting flow rates of the PVDF component, a core-shell structure of the composite fibers was obtained caused by the lower viscosity and surface tension of PVDF. In addition, a steady laminar motion of fluids was constructed based on the Reynolds number of flow fields being less than 2300. In order to investigate the formation mechanism of the microstructure, a series of Janus nozzles with different lengths were controlled to study the blending of the two immiscible components. The gravity difference between the two components might cause disturbance of the jet motion, and the PVDF component unidirectionally encapsulated the loofah to form the shell layer. Most importantly, the dry loofah/PVDF membranes could separate oil from an oil-water mixture, while the water-wetted membrane exhibited switchable separation that could separate water from the mixtures because of the hydroxyl groups of the hydrophilic loofah hydrogen-bonding with water molecules and forming a hydration layer. The composite fibers can be applied in water remediation in practice, and the method to produce core-shell structures seems attractive for technological applications involving macroscopic core-shell nano- or microfibers.

Enhanced dielectric and capacitive performance in polypropylene/poly(vinylidene fluoride) binary blends compatibilized with polydopamine

Polymer blending strategy has demonstrated to be efficient in enhancing the capacitive performance of dielectric polymers represented by poly(vinylidene fluoride) (PVDF). Special attention is paid to the polymeric reinforcements which are miscible with PVDF. Immiscible polymeric reinforcements for PVDF based blends are rarely reported because of the interfacial compatibility issue. In this work, we aimed to explore the possibility of immiscible component polypropylene (PP) in modulating the capacitive performance of PVDF. A two-step fabrication process and polydopamine compatibilizer were developed to improve the interfacial compatibility between two components. The resultant binary blend demonstrated to perform suppressed dielectric loss, improved polarization level and consequently enhanced capacitive performance. With an optimized addition of 10 wt% PP, a maximum discharge energy density of 12.1 J/cm3 and discharge efficiency of 69.3% can be obtained in blends under 350 MV/m, while those of pure PVDF were 5.7 J/cm3 and 45.6%, respectively.

Eulerian Model for Simulating Multi-Fluid Flows with an Arbitrary Number of Immiscible Compressible Components

A ($$2N+1$$)-equation model to simulate the flow of N ($$\textit{N}\ge 3$$) immiscible compressible fluids separated with interfaces is proposed. The model is based on the single velocity diffuse-interface method and includes $$N-1$$ advection equations for fluid volume fractions. Solving the advection equations with a non-linear high-order scheme commonly results in the violation of the non-negativity constraint that any arbitrary partial sum of volume fractions should be in the interval [0, 1]. First, it is shown that this constraint can be met if the $$N-1$$ advection equations are solved for some rational functions of volume fractions rather than for volume fractions themselves. The non-linear sub-cell slope reconstruction (MUSCL-type and THINC) with the proposed rational advection functions is proved to be non-oscillatory and provide the distribution of volume fractions satisfying the non-negativity constraint. Second, it is proved that the PV property (preservation of constant-pressure and constant-velocity equilibrium) is maintained providing that linear functions of volume fractions are used in the advection equations. We suggest two ways for resolving the contradiction in choosing the advection functions (functions of volume fractions) in accordance with the non-negativity constraint and the PV property. We also adopt two numerical methods—the Roe-type scheme and the HLLC scheme to solve the governing equations. Finally, the proposed numerical model is tested with several benchmark problems. The results obtained demonstrate robustness and effectiveness of the proposed numerical approach in solving multi-fluid flows with large interface deformations.

Hydrogen Stabilized RhPdH 2D Bimetallene Nanosheets for Efficient Alkaline Hydrogen Evolution.

The design of catalysts with high activity and robust stability for alkaline hydrogen evolution reaction (HER) remains a great challenge. Here, we report an efficient catalyst of two-dimensional bimetallene hydrides, in which H atoms stabilize the rhodium palladium bimetallene. The system exists because of the introduction of H that is in situ chemically released from the formaldehyde solution during the synthesis. This provides a highly stable catalyst based on an unstable combination of metal elements. Density functional theory calculations show the H is confined by electronic interactions and the Miedema rule of reverse stability of the RhPd alloy. The obtained catalyst exhibits outstanding alkaline HER catalytic performance with a low overpotential of 40 mV at 10 mA cm-2 and remarkable stability for over 10 h at 100 mA cm-2. The experimental results show that the confined H improve the activity, while the ultrathin sheet-like morphology yields stability. Our work provides guidance for synthesizing high-activity catalysts by confining heteroatoms into the crystal lattice of bimetallene and also a very novel mechanism for the growth of bimetallene made of highly immiscible components.

Multifaceted property tailoring of polyamide 6 by blending miscible and immiscible components: ternary blends of polyamide 6/polyethylene terephthalate/phenol novolac.

Ternary polymer blends comprising miscible and immiscible components are examined to improve the mechanical properties of polyamide 6 (PA6) under humid and high-temperature conditions. Miscible polymers increase the glass transition temperature (Tg), owing to their strong inter-molecular interactions, while phase-separated immiscible polymers reinforce the physical properties of PA6 as filler materials. Ternary blends exhibit these combined miscible and immiscible component contributions. Thus, in this study, ternary blends comprising PA6, polyethylene terephthalate (PET, immiscible component), and phenol novolac (PN, miscible component) are prepared by melt mixing. The PA6 stiffness in the water-absorbed state is reinforced by PET. Moreover, the proposed PA6/PET/PN ternary blends exhibit higher Tg values and lower water absorption rates than those of the PA6/PET binary blend, owing to the PN contribution. The PET and PN contributions are achieved independently and can be controlled via the composition ratios of the component polymers. Multifaceted property tailoring is thus demonstrated.

Multiphase Flow in the Gap Between Two Rotating Cylinders

The research of liquids composed of two (or more) mutually immiscible components is a new emerging area. These liquids represent new materials, which can be utilized as lubricants, liquid seals or as fluid media in biomechanical devices. The investigation of the problem of immiscible liquids started some years ago and soon it was evident that it will have a great application potential. Recently, there has been an effort to use ferromagnetic or magnetorheological fluids in the construction of dumpers or journal bearings. Their advantage is a significant change in dynamic viscosity depending on magnetic induction. In combination with immiscible liquids, qualitatively new liquids can be developed for future technologies. In our case, immiscible fluids increase the dynamic properties of the journal hydrodynamic bearing. The article focuses on the stability of single-phase and subsequently multiphase flow of liquids in the gap between two concentric cylinders, one of which rotates. The aim of the analysis was to study the effect of viscosity and density on the stability/instability of the flow, which is manifested by Taylor vortices. Methods of experimental and mathematical analysis were used for the analysis in order to verify mathematical models of laminar and turbulent flow of immiscible liquids.

Two-phase state of the melts of Fe – Cu system during their cooling in a viscometer

Alloys Fe – Cu can be characterized as a system with immiscible components (IC). This statement is based on a weak mutual solubility in the solid state. In addition, with low carbon content, the Fe – Cu system is also stratified in the liquid state [1]. Alloys with IC have a simple phase composition of almost pure components. This determines a significant practical interest in these alloys. Certain successes have been achieved in the technology of manufacturing damping alloys of the Fe – Cu– Pb system. With optimally selected technology for their preparation, it is possible to obtain the final product combining the properties of pure alloy components in the proportion required for practical application. For example, in Fe – Cu alloys, diamagnetic copper has high electrical conductivity and thermal conductivity, and ferromagnetic iron has enhanced strength characteristics compared to copper. When structure of the alloy is organized in a certain way, it is possible to obtain either a final product with high electrical conductivity and thermal conductivity of copper, enhanced strength properties of iron, or – a hard magnetic material with ductility of copper. The ironcopper system alloys were considered in [2 – 13], in which the main attention was paid to structural studies and measurements of service properties. At the same time, the dynamics of macroand microstructure formation of alloys were not analyzed. In the present work, it was the dynamics of macrostructure formation of the solid phase enriched with iron in process of crystallization of the melt during its cooling that was studied using high-temperature viscometry. Considering the final influence of the melt cooling rate on the size and morphology of crystallizing inclusions, and a significant amount of the two-phase area, special attention was paid to thermophysical analysis of the measurement mode. Analysis of reliability of the results obtained was made by the method of viscosity measuring. Phase state of the melts of Fe – Cu system was investigated during cooling by changing the damping factor. The analysis of thermophysical processes occurring in the measurement of the damping factor was carried out. It has been established that the process of measuring the damping decrement takes place under quasi-equilibrium conditions and the cooling rate is close to zero. There are no temperature gradients, both in radius and in height. For compositions Fe50Cu50 , Fe40Cu60 , Fe30Cu70 the dynamics of precipitation of the solid phase were determined.

Fabrication of microfiltration membranes from polyisobutylene/polymethylpentene blends

AbstractAn approach for fabrication of microfiltration membranes by solvent extraction of one of the immiscible components from a polymer blend was developed. Poly(4‐methyl‐1‐pentene) (PMP) was the membrane material, and poly(isobutylene) (PIB) was the extractable component. The PIB content varied in the wide range 0–45 wt%, and all blends could be melted and processed at a temperature of 240 °C. A rheological study demonstrated a pronounced non‐Newtonian behavior of PMP/PIB blends and their very low viscosity due to interlayer slip. With a PMP content of 55 and 60 wt%, it was possible to fabricate microfiltration membranes with a water permeability of 31 and 3.7 m3 m−2 h–1 bar–1, respectively. The microfiltration membranes based on both compositions demonstrated good rejection performance at the level of 93%–98% for submicron particles of phthalocyanine dye with a size of 240 nm. These results indicate that the PMP/PIB system can be utilized for fabrication of filtration membranes by means of 3D printing followed by solvent extraction. © 2019 Society of Chemical Industry

Investigation of Two-Phase State of Fe–Cu Melts during Cooling in a Viscometer

Fe–Cu alloys can be characterized as a system with immiscible components (IC). This statement is based on a weak mutual solubility in the solid state. In addition, Fe–Cu system stratifies in the liquid state at low carbon content. Alloys with ICs have a simple phase composition of almost pure components, which determines a significant practical interest in these alloys. Manufacturers have technologically succeeded in achieving damping alloys of Fe–Cu–Pb system. With proper technological preparation, the final product can be obtained by combining the properties of pure alloy components in the fraction required for practical application. For example, diamagnetic copper has high electrical conductivity and thermal conductivity in Fe–Cu alloys, while ferromagnetic iron has enhanced strength characteristics compared to copper. When the alloy structure is organized in a certain way, a final product can be obtained with high electrical conductivity and thermal conductivity of copper, enhanced strength properties of iron, or a hard magnetic material with copper ductility. The studies of iron-copper alloys focused on the structural studies and measurements of service properties. At the same time, the dynamics of macro- and microstructure alloy formation were not analyzed. In the present studies, the macrostructure formation dynamics of the solid phase enriched with iron at the crystallization melt process during cooling was studied using high-temperature viscometry. Due to the effect of the melt-cooling rate on the size and morphology of crystallizing inclusions, as well as a significant amount of the two-phase area, special attention was paid to the thermophysical analysis of the measurement mode. Analysis of the reliability of the results obtained was made by the viscosity measurement method. The phase state of Fe–Cu system melts was investigated during cooling by changing the damping factor. The analysis of thermophysical processes occurring during measuring the damping factor was carried out. The measuring process of damping decrement takes place under quasi-equilibrium conditions and the cooling rate is close to zero. There are no temperature gradients, both in radius and in height. For compositions Fe50Cu50, Fe40Cu60, and Fe30Cu70, the precipitation dynamics of the solid phase was determined.

Рroduction of 70%Cu–30%Fe alloy by SHS metallurgy and electrometallurgy. Comparative analysis of microstructures

The influence of different methods used to produce Fe–Cu alloys from immiscible components was studied. Alloys with limited solubility (LS) or pseudoalloys (PA) in a liquid or solid state have long been impossible to obtain with traditional metallurgy methods. This is why developing low-cost and simple technologies to produce such alloys and materials based on them with a possibility to set the required level of physical and mechanical properties is still a relevant problem. This study uses energy-efficient SHS metallurgy method to produce a pseudoalloy with a composition, wt.%: 70Cu–30Fe from oxide materials for the first time. This technology offers using chemical energy generated in the reaction of highly exothermic thermit compositions (in a combustion mode) making it a very energy-efficient method for cast material production. Short synthesis time (tens of seconds), and top surface of ingots protected from oxidation with an oxide melt (Al2O3) enables synthesis in atmospheric conditions. Rods with the same composition were obtained using single-stage vacuum induction remelting from pure (impurity-free) Fe and Cu components for comparative structural studies of alloy sample components. It was found that high melting temperatures of the SHS alloy provides higher solubility of Cu in Fe. Then, when crystallized, structural components are released in the form of small dispersed particles throughout the volume and form a hierarchical structure typical for the SHS alloy only. 70Cu–30Fe alloys produced in a combustion mode (SHS) have a homogeneous structure with structural components distributed uniformly throughout the sample volume, which can be of great practical interest, in particular, for making isotropic and anisotropic hard-magnetic materials with high magnetic energy.

Bioactive starch nanocomposite films with antioxidant activity and enhanced mechanical properties obtained by extrusion followed by thermo-compression

In this work bioactive starch films with antioxidant activity were developed by extrusion followed by thermo-compression. Rosemary extract was incorporated into starch-glycerol films in different concentrations (2.5%, 5% and 10% w/w with respect to starch). Despite the high mechanical and thermal energy involved during extrusion, rosemary polyphenols remained in the films without losing its activity.Starch nanocomposites were obtained by the incorporation of rosemary nanoparticles, which were formed from the immiscible components of the extract. For low extract concentration, homogeneously dispersed nanoparticles acted as reinforcement of the matrix, increasing stress and strain at break without modifying Young's modulus. At high concentration, the mechanical response was ruled by the miscible components of the extract, which acted as an additional plasticizer. In this case, nanocomposite films with higher values of strain at break and lower values of Young's modulus and stress at break were obtained. All the developed films released a high percentage of polyphenols to hydrophilic, lipophilic or acid food simulants in a short time interval. Experimental release data was fitted by Weibull equation in order to elucidate release mechanisms.According to the results of this research, rosemary extract can be incorporated into starch films by extrusion without previous encapsulation. Despite thermal and mechanical energy involved in the process, the rosemary compounds kept their antioxidant activity and were released from the bioactive films.

Properties of (Fe–B)-doped Sn–1.0Ag–0.5Cu solders prepared by mechanical alloying

To introduce boron (B) into the Sn–1.0Ag–0.5Cu (SAC105) solder, based on the thermodynamic calculations, iron (Fe) is a competent carrier component for bonding B and Sn. The Sn–Fe–B master alloys were prepared by mechanical alloying initially; then, the SAC105-0.05(Fe–B) and SAC105-0.1(Fe–B) solder alloys were prepared using 72-h-milling Sn–Fe–B master alloys. The preparation process and the properties of solders were studied in this work. For the Sn–Fe–B master alloys, the results show that with the increase in the ball-milling time, the powder changes illustrate a cold welding–crushing–cold welding cyclic process. Moreover, the supersaturated solid solubility of (Fe–B) increases gradually in the alloys’ matrix and the lattice distortion increases to 0.167% after 72-h milling. Meanwhile, the alloying degree is increasingly apparent, and after 72-h milling, the content of B in the Sn matrix reaches 2.38 wt%. For the solder alloys, with the (Fe–B) content increasing, the melting point decreases and a significant grain refinement occurs in the matrix. Compared to the benchmark SAC105, the hardness of SAC105-0.05(Fe–B) and SAC105-0.1(Fe–B) solder alloys prepared by this method is improved by 20.65% and 34.79%, respectively. The present research provides a novel approach for introducing the immiscible component into the lead-free solder alloys.

Phase Behavior and Microstructure of Symmetric Nonionic Microemulsions with Long-Chain n-Alkanes and Waxes

Microemulsions are thermodynamically stable, macroscopically isotropic mixtures of at least two immiscible components and a surfactant. Their general features, i.e. the complex phase behavior, the ultralow interfacial tensions, and the multifarious nanostructure, have been systematically elucidated in the last century. However, the efficient solubilization of long-chain n-alkanes and waxes, which plays a significant role in enhanced oil recovery, washing, and cosmetics, remains a challenge. Thus, in this work the influence of the n-alkane chain length k on the phase behavior of ternary (symmetric) microemulsions containing equal volumes of water and oil was studied. Using n-alkanes ranging from n-dodecane (C12H26) to n-dotriacontane (C32H66) and pure n-alkyl polyglycol ether (CiEj) surfactants, we found that the efficiency of the respective surfactant decreases linearly with increasing k, while the phase inversion temperature (PIT) shows a logarithmic dependence. The influence of a technical wax on the ph...

Non-isothermal Transport of Multi-phase Fluids in Porous Media. The Entropy Production

We derive the entropy production for transport of multi-phase fluids in a non-deformable, porous medium exposed to differences in pressure, temperature, and chemical potentials. Thermodynamic extensive variables on the macro-scale are obtained by integrating over a representative elementary volume (REV). Using Euler homogeneity of the first order, we obtain the Gibbs equation for the REV. From this we define the intensive variables, the temperature, pressure and chemical potentials and, using the balance equations, derive the entropy production for the REV. The entropy production defines sets of independent conjugate thermodynamic fluxes and forces in the standard way. The transport of two-phase flow of immiscible components is used to illustrate the equations.

Apatite-hosted melt inclusions from the Panzhihua gabbroic-layered intrusion associated with a giant Fe–Ti oxide deposit in SW China: insights for magma unmixing within a crystal mush

The ∼ 2-km-thick Panzhihua gabbroic-layered intrusion in SW China is unusual because it hosts a giant Fe–Ti oxide deposit in its lower zone. The deposit consists of laterally extensive net-textured and massive Fe–Ti oxide ore layers, the thickest of which is ∼ 60 m. To examine the magmatic processes that resulted in the Fe enrichment of parental high-Ti basaltic magma and the formation of thick, Fe–Ti oxide ore layers, we carried out a detailed study of melt inclusions in apatite from a ∼ 500-m-thick profile of apatite-bearing leucogabbro in the middle zone of the intrusion. The apatite-hosted melt inclusions are light to dark brown in color and appear as polygonal, rounded, oval and negative crystal shapes, which range from ∼ 5 to ∼ 50 µm in width and from ∼ 5 to ∼ 100 µm in length. They have highly variable compositions and show a large and continuous range of SiO2 and FeOt with contrasting end-members; one end-member being Fe-rich and Si-poor (40.2 wt% FeOt and 17.7 wt% SiO2) and the other being Si-rich and Fe-poor (74.0 wt% SiO2 and 1.20 wt% FeOt). This range in composition may be attributed to entrapment of the melt inclusions over a range of temperature and may reflect the presence of µm-scale and immiscible Fe-rich and Si-rich components in different proportions. Simulating results for the motion of Si-rich droplets within a crystal mush indicate that Si-rich droplets would be separated from Fe-rich melt and migrate upward due to density differences in the interstitial liquid when the magma unmixed. Migration of the Si-rich, immiscible liquid component from the interstitial liquid caused the remaining Fe-rich melt in the lower part to react with plagioclase primocrysts (An59–60), as evidenced by fine-grained lamellar intergrowth of An-rich plagioclase (An79–84) + clinopyroxene in the oxide gabbro of the lower zone. Therefore, magma unmixing within a crystal mush, combined with gravitationally driven loss of the Si-rich component, resulted in the formation of Fe-rich, melagabbro and major Fe–Ti oxide ores in the lower part and Si-rich, leucogabbro in the upper part of the intrusion.