Liquid Behavior Research Articles

Solid-liquid equilibrium of glucosamine hydrochloride in four binary solvents: Experiments, modeling, and molecular simulation

Glucosamine hydrochloride (GAH) is a marine biological preparation derived from natural chitin and improves articular cartilage metabolism. In this study, the solubility of GAH in four binary solvents (water + methanol, water + ethanol, water + isopropanol, and water + acetone) was gravimetrically determined over the temperature range of 283.15 K to 323.15 K. The solubility of GAH were found increasing monotonically with water content and temperature. In alcohol mixtures, the solubility of GAH can be ranked as: (water + methanol) > (water + ethanol) > (water + isopropanol). Four thermodynamic models (the modified Apelblat equation, van't Hoff equation, (CNIBS)/R-K model and Jouyban-Acree model) were used to correlate the experimental solubility data, which the (CNIBS)/R-K model showed the best fitting performance. The dissolution thermodynamic properties of GAH were also calculated. The results indicate that the dissolution process is driven by both entropy and enthalpy. To explore the solid–liquid equilibrium behavior from molecular level, the Hirshfeld surface of GAH crystal was generated and molecular dynamics simulations of mixed systems were performed. Based on equilibrium configurations of different mixtures, molecular interactions between solvent–solvent and solute–solvent were calculated. Meanwhile, the simulation snapshots and radial distribution function plots were analyzed to interpret association of solvents.

Non-covalent interactions and morphologies as tools for structure-driven informatics: rationalizing the behavior of ionic liquids

Non-covalent interactions and morphologies as tools for structure-driven informatics: rationalizing the behavior of ionic liquids

Generic deformation channels for critical Fermi surfaces in the collisionless regime

Using a quantum Boltzmann equation framework, we analyse the nature of generic low-energy deformations of a critical Fermi surface, which exists at the non-Fermi liquid fixed point of a system consisting of fermions interacting with massless bosons. The non-Fermi liquid behaviour arises due to the itinerant quasiparticles of the Fermi surface interacting strongly with the massless bosons, which on the other hand undergo Landau damping as a result of the mutual interactions. Focussing on the collisionless regime, where we neglect the collision integral, we chalk out the possible excitations spanning the entire spectrum of angular momentum (ℓ) channels (i.e., including both small and large values of ℓ). The excitations are of two types: particle-hole like localized excitations forming an energy band (or continuum) and delocalized collective modes with discrete energies. Although we find a collective mode analogous to the zero sound of a Fermi liquid, its dispersion shows a crossover from a Ω∼|q|6/5 behaviour to the usual Ω∼|q| dependence, where Ω and q represent the frequency and momentum, respectively. We estimate the frequency scale at which this crossover takes place. We also determine the boundary for the particle-hole continuum in the Ω–q plane, and observe a crossover from Ω∼|q|3/2 to Ω∼|q| behaviour, determined by another crossover frequency scale.

Investigation of aggregation behavior and surface properties of cationic surface-active ionic liquids and sodium carboxymethylcellulose mixed systems

Abstract The impact of different concentrations of sodium carboxymethyl cellulose (NaCMC) on the micellization process in cationic, ester-functionalized, ethyl-substituted imidazolium-based surface-active ionic liquids (SAILs) ([C n Eeim]Br where, n = 12, 14, 16) were investigated using specific conductivity and surface tension measurements at 298 K. The study focused on determining the critical micelle concentration (CMC) of the three pure SAILs and their mixtures with NaCMC to evaluate various thermodynamic and interfacial parameters. The results showed that the CMC values decreased significantly with increasing hydrophobicity of the SAILs, while the CMC increased with a gradual increase in the NaCMC mole fraction in the SAIL–NaCMC mixed systems. It was observed that the excess free energy of micellization ( ∆ G e x m ${{\increment}G}_{ex}^{m}$ ) and the minimum free energy of surface at equilibrium ( ∆ G min s ${{\increment}G}_{\mathrm{min}}^{s}$ ) exhibited an opposite behaviour, indicating that the formed mixed micelles were stable while the formed surface was unstable. The results of this study are useful for evaluating the properties of SAIL–NaCMC mixed systems to improve and better understand their applications in the food, medical and cosmetic industries.

Influence of Morpholinium-Based Ionic Liquid on the Aggregation Behavior of Cationic Surfactant and Imidazolium-Based Ionic Liquid with the same Alkyl Chain in an Aqueous Medium

Influence of Morpholinium-Based Ionic Liquid on the Aggregation Behavior of Cationic Surfactant and Imidazolium-Based Ionic Liquid with the same Alkyl Chain in an Aqueous Medium

Efekty lepkosprężyste w warunkach nawadniania kolektora szczelinowo-porowego cieczą wodno-polimerową

The work is devoted to the numerical simulation of the flow of simple and viscoelastic (polymer solution) fluids through a fracture by using polymer solutions for enhanced oil recovery from a reservoir. Polymer solutions have viscoelastic properties. Therefore, when polymer solution flows through the slot, we use the well-known Maxwell’s fluid model with the Jaumann derivative to evaluate deformation characteristics of the flow (stream functions, distributions of the longitudinal velocity gradient and normal stress) resulting in the manifestation of abnormal (compared with the behaviour of the ordinary fluid) effects. The case of slow flow is considered. In this case, the inertial terms can be neglected, the velocities, stresses, and stream functions can be written as the decomposition by Weisenberg number, and we can assume that the Weissenberg number is less than one. The determined regularities of viscoelastic (polymer solution) liquid behaviour with longitudinal velocity gradient and the elastic deformations effects manifested in this case have a decisive meaning in understanding the mechanism of anomalously high oil recovery capacity of a reservoir by using water-polymer flooding of the fractured-porous reservoir. Understanding the nature of the effects of elastic deformations under the conditions of water-polymer flooding of the fractured-porous reservoir enables hydrodynamic calculations of the optimal flow of the polymer solution. One of the main issues that need to be solved when developing the technology for increasing oil recovery from formations using polymer solutions is to determine the optimal flow regime in the fractured-porous reservoir. The calculation results verify the ideas obtained from the experimental solution of this problem concerning the strain-stress state of polymer macromolecules (liquid elements) during polymer flow in the inlet area of the fracture in the oil reservoir and confirm the possibility of using numerical analysis of convergent polymer flow for calculating longitudinal velocity gradients in the inlet area of the fracture and can also serve as additional substantiation of the proposed earlier mechanism for increasing oil recovery from reservoirs by using polymer solutions.

Structural, spectral, and dynamical behaviors of biodegradable choline-based ionic liquids (CBILs) confined inside neutral and charged mxene nanopores for supercapacitor applications

This study explores the potential of using biodegradable choline-based ionic liquids (CBILs) as a more sustainable and eco-friendly alternative to classical ILs in the field of electrolyte media for energy storage devices. While previous studies have focused on electrostatic and capacitance properties, it is important to also consider dynamics and structural behavior when choosing adjustable electrolytes and electrodes. In this regard, molecular dynamics simulations were used to study the structural, spectral, and dynamical behaviors of two CBILs ([Ch][Sa] and [Ch][β-Ala]) inside MXene nanopores with varying pore size and surface charge density. As the pore size decreases, the number of hydrogen bonds in the first layer decreases from 0.447 to 0.122 and 0.154–0.063 in [Ch][Sa] and [Ch][β-Ala], respectively. Also, the presence of an aromatic ring benefits packing efficiency, causing [Sa]- to have a parallel orientation relative to MXene surface. Applying a fixed charge (1.8–7.2 μC/cm2) on MXene electrodes results in the formation of an electric double layer (EDL). At higher surface charge densities, there is slower dynamics and lower structural correlations between anions and cations. Moreover, Infrared (IR) spectra show blue and red shifts for the O-H bond in choline and carbonyl C-O stretching vibrational modes in anions, respectively, due to the interaction of anions with the MXene surface in the first layer reducing their interaction with cations. The results of our research may potentially lead to the creation of novel energy storage devices that are eco-friendly, utilizing MXene electrodes and CBILs as electrolytes.

Magnetic Field as an Important Tool in Exploring the Strongly Correlated Fermi Systems and Their Particle–Hole and Time-Reversal Asymmetries

In this review, we consider the impact of magnetic field on the properties of strongly correlated heavy-fermion compounds such as heavy-fermion metals and frustrated insulators with quantum spin liquid. Magnetic field B can be considered a universal tool, allowing the exploration of the physics controlling the remarkable properties of heavy-fermion compounds. These vivid properties are T/B scaling, exhibited under the application of magnetic field B and at fixed temperature T, and the emergence of Landau Fermi liquid behavior under the application of magnetic field. We analyze the influence of quasiparticle–hole asymmetry on the properties of heavy-fermion (HF) compounds such as the universal scaling behavior of the thermopower S/T exhibited under the application of magnetic field B. We show that universal scaling is demonstrated by different HF compounds such as β-YbAlB4, YbRh2Si2, and strongly correlated layered cobalt oxide [BiBa0.66K0.36O2]CoO2. Analyzing YbRh2Si2, we show that the T/B scaling behavior of S/T is violated at the antiferromagnetic phase (AF) transition. The residual resistivity ρ0 and the density of states N0 experience jumps at the AF transition, causing two jumps in the thermopower and its sign reversal. Our consideration is based on the flattening of the single-particle spectrum that strongly affects ρ0 and N0 and leads to the violation of particle–hole symmetry. The particle–hole asymmetry generates the asymmetrical part Δσd(V) of tunneling differential conductivity σd(V), Δσd(V)=σd(V)−σd(−V), where V is the voltage bias. We demonstrate that in the presence of magnetic field, the quasiparticle–hole asymmetry vanishes, the LFL behavior is restored, and the asymmetry disappears. Our calculations of the mentioned properties of HF compounds, based on the fermion condensation theory, are in good agreement with the experiment and support our conclusion that the fermion condensation theory is capable of describing the properties of HF compounds, including those exhibited under the application of magnetic field.

Non-Fermi liquid behavior in a simple model of Fermi arcs and pseudogap

In this paper, we consider a perturbed version of a very simple and exactly solvable model that supports Fermi arcs and pseudogap in its ground state and excitation spectrum, which includes Hubbard-like interactions in both momentum and real spaces. We find that the combined effects give rise to non-Fermi liquid behavior in the electron self-energy. This points to a novel mechanism that leads to non-Fermi liquid behavior, which is of strong current interest in the context of strongly correlated metals, that often become superconductors. Comparison will be made with phenomenology of high- temperature cuprate superconductors.

Thermodynamic analysis and molecular dynamic simulation of solid–liquid equilibrium behavior of antipsychotic drug aripiprazole (Form III) in three binary solvent mixtures

Aripiprazole (APZ), an effective second-generation antipsychotic drug indicated for the treatment of schizophrenia, was chosen to investigate its solubility in three binary solvent mixtures at the temperature range of 278.15–318.15 K. Due to clinical usage Form III is metastable, and the solubility was studied via the synthetic method. It was found that in the butanone + acetone and butanone + ethyl acetate mixed solvent systems, the solubility values of APZ Form III increased with the increase of the proportion of butanone solvent, and the maximum mole fraction solubility at each selected temperature point ranges from 0.001924 to 0.009015. However, in the mixed solvent system of butanone and n-propanol, the solubility of APZ Form III reaches its maximum when the molar fraction of butanone is 0.6 with the maximum mole fraction solubility at each selected temperature point ranging from 0.003126 to 0.012721. The modified Apelblat model, λh model, Van’t Hoff model, and NRTL model were used to correlate the experimental solubility data of APZ Form III, and the results showed that these models are suitable. In addition, according to the result of mixing thermodynamic functions, the negative values of ΔmixG and ΔmixH in all binary solvent mixtures are negative, indicating that the dissolution process of APZ Form III in the binary solvent mixtures is spontaneous and entropy-driven. Furthermore, the molecular dynamic simulations were used to illustrate and understand the dissolution behavior of APZ Form III in selected solvents from a molecular perspective.

An insight into the influence of chlorine position on the ion-solvation and ion-association behaviour of pyridinium-based ionic liquids in alcohol-water mixed media and temperatures

An insight into the influence of chlorine position on the ion-solvation and ion-association behaviour of pyridinium-based ionic liquids in alcohol-water mixed media and temperatures

Computational fluid dynamics-discrete element method simulation of stirred tank reactor for graphene production

Liquid phase exfoliation (LPE) process for graphene production is usually carried out in stirred tank reactor and the interactions between the solvent and the graphite particles are important as to improve the production efficiency. In this paper, these interactions were revealed by computational fluid dynamics–discrete element method (CFD-DEM) method. Based on simulation results, both liquid phase flow hydrodynamics and particle motion behavior have been analyzed, which gave the general information of the multiphase flow behavior inside the stirred tank reactor as to graphene production. By calculating the threshold at the beginning of graphite exfoliation process, the shear force from the slip velocity was determined as the active force. These results can support the optimization of the graphene production process.

CFD-PBE Simulation of Flow Dynamics and Mass Transfer in Two-Stage Countercurrent Mixer-Settler

Flow condition and mass transfer behavior of liquid–liquid extraction in a two-stage countercurrent extractor are investigated experimentally and numerically. CFD-PBE simulation is adopted to analyze the impact of operating parameters, including impeller speed, residence time, and organic-aqueous ratio of feed flow on volume fraction and droplet size of dispersed phase and volumetric mass transfer coefficient. Droplet size distribution is calculated by considering breakage and coalescence of dispersed phase. The allocation of dispersed phase between stages is found to be determined by impeller speed. Meanwhile, the allocation of dispersed phase between mixers and settlers is governed by residence time and organic-aqueous ratio of feed flow. Turbulence intensity, volume fraction, and droplet size distribution are revealed to be dominating parameters that affect the spatial nonuniform distribution of volumetric mass transfer coefficient. The mass transfer rate can be improved by increasing impeller speed in two stages. Higher residence time and organic-aqueous ratio of feed flow, however, have opposite effects on mass transfer rate in stage-1 and stage-2.

Direct electrification of silicon microfluidics for electric field applications

Microfluidic systems are widely used in fundamental research and industrial applications due to their unique behavior, enhanced control, and manipulation opportunities of liquids in constrained geometries. In micrometer-sized channels, electric fields are efficient mechanisms for manipulating liquids, leading to deflection, injection, poration or electrochemical modification of cells and droplets. While PDMS-based microfluidic devices are used due to their inexpensive fabrication, they are limited in terms of electrode integration. Using silicon as the channel material, microfabrication techniques can be used to create nearby electrodes. Despite the advantages that silicon provides, its opacity has prevented its usage in most important microfluidic applications that need optical access. To overcome this barrier, silicon-on-insulator technology in microfluidics is introduced to create optical viewports and channel-interfacing electrodes. More specifically, the microfluidic channel walls are directly electrified via selective, nanoscale etching to introduce insulation segments inside the silicon device layer, thereby achieving the most homogeneous electric field distributions and lowest operation voltages feasible across microfluidic channels. These ideal electrostatic conditions enable a drastic energy reduction, as effectively shown via picoinjection and fluorescence-activated droplet sorting applications at voltages below 6 and 15 V, respectively, facilitating low-voltage electric field applications in next-generation microfluidics.

The key role of interfacial non-bonding interactions in regulating lubricant viscosity using nanoparticles

The feasibility of using nanoparticles (NPs) as lubricant viscosity modifiers has attracted considerable attention as they can increase/decrease the lubricant viscosity. However, due to the lack of theoretical guidance for interface design, the practical application of NP viscosity modifiers is limited. In this study, molecular dynamics simulations are performed to analyze the non-bonding interactions of four typical lubricating oil/NP solid–liquid interfaces with different interface polarities. A model of the mechanism through which the NPs regulate the shear viscosity of the lubricating oil is proposed based on the solid–liquid interface slip behavior, which is verified experimentally. It is found that the shear resistance of the interface is determined by the "liquid all-atomic Coulomb potential energy" (LACPE) and is positively correlated with the “potential well” values of the LACPE distributed in the tangent plane parallel to the wall. Adjusting the characteristics of the solid surface and the "polar units", which are inside the lubricant molecules, as well as the linking modes between the polar units, is proposed as a means to regulate the interfacial shear resistance. This work could provide guidance for interface design and the R&D of nanoscale viscosity modifiers.

Constructing a Quasi-Liquid Interphase to Enable Highly Stable Zn-Metal Anode

Rechargeable aqueous Zn-metal batteries have attracted widespread attention owing to their safety and low cost beyond Li-metal batteries. However, due to the lack of the solid electrolyte interphase, problems such as dendrites, side reactions and hydrogen generation severely restrict their commercial applications. Herein, a quasi-liquid interphase (QLI) with a “solid–liquid” property is constructed to stabilize the Zn-metal anode. The synergistic effect of solid and liquid behavior ensures the stable existence of QLI and simultaneously enables the interphase dynamic and self-adaptive to the anode evolution. Electrolyte erosion, Zn2+ diffusion and side reactions are inhibited during long-term cycling after introducing QLI, significantly improving the cycling stability and capacity retention of the symmetric and full cells modified with QLI (Zn@QLI), respectively. Constructing an interphase with a quasi-liquid state represents a promising strategy to stabilize the metal anodes in aqueous electrolytes and even extend to organic electrolytes.

Morse fluids in the immediate vicinity of the critical point: Calculation of thermodynamic coefficients

The previously proposed approach for the microscopic description of the critical behavior of Morse liquids based on the cell fluid model is applied to the case where the parameters of the Morse interaction potential correspond to alkali metals (sodium and potassium). The critical temperatures, densities, and pressures obtained for sodium and potassium agree with the experimental results. The thermodynamic coefficients (isothermal compressibility, density fluctuations, and thermal expansion) of sodium are investigated in the supercritical temperature region. Numerical calculations of thermodynamic coefficients are performed close to the critical point, where carrying out theoretical and experimental research is challenging. The change in compressibility with increasing density at various temperature values is traced. The behavior of density fluctuations approaching the critical point is shown for different temperatures. The variation in the magnitude of the thermal expansion with increasing temperature for different pressure values is illustrated.

Pore scale study of ice melting and multiphase flow in gas diffusion layer with porosity gradient in PEMFC

An enthalpy-based multi-component multiphase flow model is established by using the lattice Boltzmann method (LBM), and the ice melting and liquid water flow behavior during cold start process in gas diffusion layers (GDLs) with porosity gradients of proton exchange membrane fuel cell (PEMFC) are captured. GDLs with five porosity gradients are considered to explore the ice melting efficiency, temperature distribution characteristics and liquid water transport. The results show that the ice melting rate is significantly affected by the porosity distribution. The model of porosity decreasing gradually from near catalyst layer to near channel side (M4) greatly improves ice melt efficiency by up to 61.44%, while the 'V' porosity gradient (M2) and the model of porosity increasing gradually from near catalyst layer to near channel side (M3) prolong the heating and melting time of 15.6% and 25.56% respectively. The arrangement of small porosity structure near the channel side enhance the convective and conduction heat transfer. The hydrophilicity of the surface of fibers is beneficial to ice melting but hinders the discharge of liquid water. Considering the ice melting efficiency and drainage performance, the GDL with porosity gradient can be used when selecting the auxiliary measure of inlet preheating.

Liquid–Liquid Equilibria of Glycerol + Alcohol + Safflower Biodiesel Systems: Measurement and Modeling

Liquid–liquid equilibrium (LLE) for the biodiesel + glycerol + alcohol system is essential for the design, operation, process optimization, and economic evaluation of a biodiesel production plant. In this work, methyl and ethyl safflower biodiesels were produced from safflower (Carthamus tinctorius L.) seed oil. New LLE experimental datasets were obtained for the glycerol (1) + methanol/ethanol (2) + methyl/ethyl safflower biodiesel (3) systems at 298.15 and 318.15 K under atmospheric pressure. Binodal curves, tie-lines, distribution coefficients, and selectivity were determined. Data reliability was confirmed using the Othmer–Tobias correlation. LLE data were correlated with the UNIQUAC model satisfactorily, with deviations between 0.70 and 2.79% for all studied systems. The consistency of the estimated binary interaction parameters of the UNIQUAC model was ascertained. Finally, through process simulations in Aspen Hysys software, it was verified that the UNIFAC LLE model, along with the UNIQUAC model, can also be used adequately to describe the liquid–liquid behavior of biodiesel separators, provided that the biodiesel composition is accurately known.

Ebola virus inclusion bodies are liquid organelles whose formation is facilitated by nucleoprotein oligomerization

ABSTRACT Viral RNA synthesis of several non-segmented, negative-sense RNA viruses (NNSVs) takes place in inclusion bodies (IBs) that show properties of liquid organelles, which are formed by liquid–liquid phase separation of scaffold proteins. It is believed that this is driven by intrinsically disordered regions (IDRs) and/or multiple copies of interaction domains, which for NNSVs are usually located in their nucleo – and phosphoproteins. In contrast to other NNSVs, the Ebola virus (EBOV) nucleoprotein NP alone is sufficient to form IBs without the need for a phosphoprotein, and to facilitate the recruitment of other viral proteins into these structures. While it has been proposed that also EBOV IBs are liquid organelles, this has so far not been formally demonstrated. Here we used a combination of live cell microscopy, fluorescence recovery after photobleaching assays, and mutagenesis approaches together with reverse genetics-based generation of recombinant viruses to study the formation of EBOV IBs. Our results demonstrate that EBOV IBs are indeed liquid organelles, and that oligomerization but not IDRs of the EBOV nucleoprotein plays a key role in their formation. Additionally, VP35 (often considered the phosphoprotein-equivalent of EBOV) is not essential for IB formation, but alters their liquid behaviour. These findings define the molecular mechanism for the formation of EBOV IBs, which play a central role in the life cycle of this deadly virus.