Liquid Properties Research Articles

Dependence of Carboxylate Anions on Physicochemical Properties of Tributyloctylphosphonium-Based Ionic Liquids

A new group of tributyloctylphosphonium-based ionic liquids containing several carboxylate anions was designed, prepared and physicochemically characterized. All phosphonium carboxylates obtained in this study became viscous liquids at room temperature. The formate-based ionic liquid exhibited the highest density and number density due to the smallest anion size. All ionic liquids exhibited typical ionic conduction behavior, since the viscosity decreased and the conductivity increased with increasing temperature. It was also found that the viscosity tended to decrease with increasing the carbon numbers of the alkyl chains of lower carboxylate anions. Compared to the propionate-based ionic liquids, lactate-based ionic liquids exhibited higher viscosity. The phosphonium ionic liquids based on carboxylate anions showed higher thermal stability than nitrogen-based counterpart ionic liquids.

Physicochemical and Thermal Behaviors of Room-Temperature Phosphonium Ionic Liquids Based on Fluorosulfonyl(trifluoromethylsulfonyl)Amide Anion As Potential Electrolytes

The physicochemical properties of novel room-temperature ionic liquids based on quaternary phosphonium cations in combination with asymmetric fluorosulfonyl(trifluoromethylsulfonyl)amide anion were reported. It was found that such phosphonium ionic liquids showed lower melting points than those of the conventional amide anion-based ionic liquids. Typical density and transport property behaviors for ionic liquids were observed. Several phosphonium ionic liquids based on fluorosulfonyl(trifluoromethylsulfonyl)amide anion exhibited low viscosities. The phosphonium ionic liquids based on fluorosulfonyl(trifluoromethylsulfonyl)amide anion exhibited relatively low thermal stability when compared to the corresponding conventional amide anion-based ionic liquids.

Control of photothermal liquid jets through microbubble Regulation: Fundamental mechanisms and Developing Strategies

Plasmon-induced photoacoustic streaming, considered as a potential application for micro-pumps in microfluidics, currently encounters ongoing debates concerning its fundamental mechanisms. In this study, we investigate the crucial role played by microbubbles in generation of jets in an ethanol aqueous solution. The power density threshold for bubble generation and its dependency on jet initiation are confirmed and the microbubble behavior is well regulated by manipulating the laser and liquid properties. Through simulations coupling fluidic and thermal fields, the significant role of Marangoni effect is validated in jet formation. Specifically, the temperature gradient of microbubbles is determined to be a pivotal factor in the generation of collimated jets. Additionally, factors influencing jetting, such as microbubble size and temperature gradients are studied, and noticeably, a stabilized jet lasting over 4 h is achieved based upon.

Predicting imidazolium ionic liquid properties with a simple molecular volume-based SAFT-VR Mie approach

Each thermodynamic model requires a distinct set of parameters for each component and these parameters must be transferable beyond their original estimation domain to accurately predict a variety of thermodynamic properties. Previous work introduced and evaluated a novel parametrization method for the solubility of ionic liquids in CO2 or CH4 [Chem. Eng. Sci. 2024, 285, 119610]. This methodology provides a fast and efficient way to evaluate ionic liquids by requiring only their molecular volume. In this study, the approach is extended to include both pure ionic liquids, examining properties such as density, isobaric heat capacity, isobaric expansivity, isothermal compressibility, and speed of sound, as well as their mixtures with ethanol or water, focusing on speed of sound, and excess enthalpy. Ionic liquids are modeled as both non-associating and associating components. Overall, the approach demonstrates good estimates and holds potential for extension to other models and systems.

Closure to the PRISM equation derived from nonlinear response theory.

Nonlinear response theory is employed to derive a closure to the polymer reference interaction site model equation. The closure applies to a liquid of neutral polymers at melt densities. It can be considered a molecular generalization of the mean spherical approximation (MSA) closure of Lebowitz and Percus to the atomic Ornstein-Zernike (OZ) equation and is similar in some aspects to the reference "molecular" MSA (R-MMSA) closure of Schweizer and Yethiraj to PRISM. For a model binary blend of freely-jointed chains, the new closure predicts an unmixing critical temperature, Tc, via the susceptibility route that scales linearly with molecular weight, N, in agreement with Flory theory. Predictions for Tc of the new closure differ greatest from those of the R-MMSA at intermediate N, the latter being about 40% higher than the former there, but at large N, both theories give about the same values. For an isotopic blend of polyethylene, the new and R-MMSA closures predict a Tc about 25% higher than the experimental value, which is only moderately less accurate than the prediction of atomic OZ-MSA theory for Tc of methane. In this way, the derivation and its consequences help to identify the ingredients in a theory needed to properly model the equilibrium properties of a polymeric liquid at both short and long lengthscales.

Liquid state properties and amorphous solidification kinetics of multicomponent Fe_{50-x}Co_{x}Cr_{14}Mo_{14}C_{9}B_{8}Tm_{5} alloys investigated under containerless processing conditions.

The liquid state thermophysical properties and amorphous solidification kinetics of Fe_{50-x}Co_{x}Cr_{14}Mo_{14}C_{9}B_{8}Tm_{5} (x=10, 15, 20, and 25) alloys were explored by electromagnetic and electrostatic levitation techniques. It was found that the surface tension of liquid alloys with Fe contents below 30 at.% had a strong temperature dependence. The high surface tension led to a sharp increase in the interfacial free-energy penalty. A high nucleation barrier was formed inside the melt, which greatly inhibited the nucleation rate. The liquid viscosity revealed the strong liquid feature of this alloy series, which became the dominant kinetic factor determining their solidification mechanisms. The high viscosity hindered atomic diffusion and delayed nucleation. The long crystallizing incubation time of Fe_{30}Co_{20}Cr_{14}Mo_{14}C_{9}B_{8}Tm_{5} ensured a strong glass-forming ability and a low critical cooling rate of 2.11×10^{3}Ks^{-1}. As a result, a bulk metallic glass rod with an 8-mm diameter was successfully prepared by a convenient casting procedure. This rod could remain in a glassy state at a higher temperature and over a wider temperature range due to its high glass-transition temperature and large undercooled liquid region. The apparent activation energy for nucleation was derived as 463.8 kJmol^{-1} according to the nonisothermal crystallization kinetics, indicating that the bulk metallic glass had to absorb a large amount of energy to overcome the potential barriers before nucleation and thus exhibited excellent thermal stability.

3D printed degradable hydrogel evaporator for high-efficiency, environmental-friendly solar alkaline-water evaporation

Solar evaporation is a simple, cost-effective method for producing clean water that does not require complex infrastructure and fossil energy. Although there have been significant advances in hydrogel solar evaporators, their widespread applications are still hampered by challenges related to customizing the structures to optimize solar evaporation rates and managing the pollution associated with waste hydrogel evaporators. To address these issues, we construct a customizable in structure, highly efficient and degradable interfacial solar evaporator using three-dimensional (3D) printing technique. The complex 3D microstructures can significantly enhance sunlight absorption through multiple surface reflections and anti-reflection effects, which can achieve customized evaporation performance. The optimized tree-shaped hydrogel evaporators can achieve a high evaporation rate of 2.41 kg m–2 h−1 under 1 sun. Importantly, the hydrogel evaporators exhibit degradation properties in alkaline liquids. These components can be integrated into the environment, reducing their impact on the environment and achieving sustainable utilization, offering a promising solution for alkaline wastewater purification and demonstrating the potential of environmental-friendly solar evaporator technology.

Design of novel copper(I) metallomesogens with benzoylthiourea ligands having peripherally connected cyano or fluoro groups

A new set of liquid crystals based on copper(I) complexes with a cyano or fluoro group attached at the para position of an aromatic ring in a benzoyl thiourea ligand was prepared and studied for their liquid crystalline properties. Incorporating electron-withdrawing fluoro or cyano groups into the structural matrix can enhance their thermal stability, phase transition temperatures, and optical properties. The prepared Cu(Ln)2X compounds, where X = Cl, Br, or I, and 4-(dodecyloxy)-N-((4-fluorophenyl)carbamothioyl)benzamide (L1), N-((4-cyanophenyl)carbamothioyl)-4-(dodecyloxy)benzamide (L2), N-((4-fluorophenyl)carbamothioyl)-3,4-bis(octyloxy)benzamide (L3), and N-((4-cyanophenyl)carbamothioyl)-3,4-bis(octyloxy)benzamide (L4) displayed a SmA mesophase depending on the type of the attached terminal group (F or CN), number of alkoxy chains (one or two) and the nature of the halide ion coordinated to the metal center (Cl, Br or I). The structures of the compounds were characterized by 1H and 13C NMR, ESI-MS and IR studies, and their mesomorphic properties were investigated via a combination of polarising optical microscopy (POM), differential scanning calorimetry (DSC), and powder X-ray diffraction studies. These compounds were stable throughout the temperature range of the mesophases. This study further reiterates the consequential effect of incorporating cyano or fluoro groups on the mesomorphic and the size of the halide ions of the studied compounds.

Modeling of high-pressure transient gas-liquid flow in M-shaped jumpers of subsea gas production systems

Two-phase flow with low liquid loads is common in high-pressure natural gas offshore gathering and transmission pipelines. During gas production slowdowns or shutdowns, an accumulation of liquid in the lower sections of subsea pipelines may occur. This phenomenon is observed in jumpers that connect different units in deep-water subsea gas production facilities. The displacement of the accumulated liquid during production ramp-up induces temporal variations in pressure drop across the jumper and forces on its elbows, resulting in flow-induced vibrations (FIV) that pose potential risks to the structural integrity of the jumper. To bridge the gap between laboratory experiments and field conditions, transient 3D numerical simulations were conducted using the OpenFOAM software. These simulations facilitated the development of a mechanistic model to elucidate the factors contributing to increased pressure and forces during the liquid purging process. The study examined the influence of gas pressure level, pipe diameter, initially accumulated liquid amount, liquid properties, and gas mass flow rate on the transient pressure drop and the forces acting on the jumper's elbows. The critical gas production rate required for complete liquid removal of the accumulated liquid was determined, and scaling rules were proposed to predict the effects of gas pressure and pipe diameter on this critical value. The dominant frequencies of pressure and force fluctuations were identified, with low-pressure systems exhibiting frequencies associated with two-phase flow phenomena and high-pressure systems showing frequencies attributed to acoustic waves.

Understanding the relationship between structural and dynamic properties in binary Mg-Al metallic liquids from molecular dynamics simulations

The structure and dynamics of the Mg-Al alloy for the different compositions were investigated using the embedded atom method (EAM) of molecular dynamics modeling. The results found that the icosahedral-like, mixed, and crystal-like increases with the temperature during the cooling process. When the temperature reaches the glass transition temperature (Tg) the last two types of clusters decrease with the temperature. The temperature Tg was determined using the Wendt-Abraham parameter, which found that it increases with increases in the fraction of Al. Investigations also revealed that the activation energy (Ea) decreases at higher temperatures and increases at temperatures below Tg. Additionally, viscosity was computed using the Vogel–Fulcher–Tammann (VFT) equation, showing a decrease in temperature in the supercooled liquid state. Moreover, an increase in the fraction of Al resulted in reduced fragility of the liquids.

Monte Carlo simulations of glass-forming liquids beyond Metropolis.

Monte Carlo simulations are widely employed to measure the physical properties of glass-forming liquids in thermal equilibrium. Combined with local Monte Carlo moves, the Metropolis algorithm can also be used to simulate the relaxation dynamics, thus offering an efficient alternative to molecular dynamics. Monte Carlo simulations are, however, more versatile because carefully designed Monte Carlo algorithms can more efficiently sample the rugged free energy landscape characteristic of glassy systems. After a brief overview of Monte Carlo studies of glass-formers, we define and implement a series of Monte Carlo algorithms in a three-dimensional model of polydisperse hard spheres. We show that the standard local Metropolis algorithm is the slowest and that implementing collective moves or breaking detailed balance enhances the efficiency of the Monte Carlo sampling. We use time correlation functions to provide a microscopic interpretation of these observations. Seventy years after its invention, the Monte Carlo method remains the most efficient and versatile tool to compute low-temperature properties in supercooled liquids.

Glaciation of mixed-phase clouds: insights from bulk model and bin-microphysics large-eddy simulation informed by laboratory experiment

Abstract. Mixed-phase clouds affect precipitation and radiation differently from liquid and ice clouds, posing greater challenges to their representation in numerical simulations. Recent laboratory experiments using the Pi Cloud Chamber explored cloud glaciation conditions based on increased injection of ice-nucleating particles. In this study, we use two approaches to reproduce the results of the laboratory experiments: a bulk scalar mixing model and large-eddy simulation (LES) with bin microphysics. The first approach assumes a well-mixed domain to provide an efficient assessment of the mean cloud properties for a wide range of conditions. The second approach resolves the energy-carrying turbulence, the particle size distribution, and their spatial distribution to provide more details. These modeling approaches enable a separate and detailed examination of liquid and ice properties, which is challenging in the laboratory. Both approaches demonstrate that, with an increased ice number concentration, the flow and microphysical properties exhibit the same changes in trends. Additionally, both approaches show that the ice integral radius reaches the theoretical glaciation threshold when the cloud is subsaturated with respect to liquid water. The main difference between the results of the two approaches is that the bulk model allows for the complete glaciation of the cloud. However, LES reveals that, in a dynamic system, the cloud is not completely glaciated as liquid water droplets are continuously produced near the warm lower boundary and subsequently mixed into the chamber interior. These results highlight the importance of the ice mass fraction in distinguishing the mixed-phase clouds and ice clouds.

Thermophysical and transport properties of a pyrrolidinium-based ionic liquid confined in silica

Ionic liquid (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyrrTFSI) was confined in silica (Aerosil A380) by direct mixing. The resulting BMPyrrTFSI/xSiO2 ionogel (x – from 2.3 to 6.7 wt%) was studied by TG, DSC, conductometry and viscometric methods. For confined IL, a decrease in the Tm and Ts-s by 14–16 °C and an increase in the Tg, and Tcc by 4–5 °C were found. With an increase in xSiO2, the opposite dynamics of the decomposition temperatures Tonset and Tpeak, and a disproportionate decrease in ionic conductivity were observed. The change in the properties of BMPyrrTFSI under conditions of limited geometry of the silica matrix is explained in the terms by the interaction of the IL and SiO2, as well as the conformation features of the cation and anion. In the first time, parameters such as the fragility index D and the formation factor F were also discussed for such systems. As a result, BMPyrrTFSI/4.5 wt% SiO2 ionogel (0.2 S m−1, 20 °C) was proposed as a promising electrolyte for application in electrochemical devices. This study may be useful for creating quasi-solid electrolytes based on ILs and inorganic materials.

Liquid state property and rapid peritectic solidification of refractory Mo-33.3 at.% Zr alloy under electrostatic levitation condition

The thermophysical properties and rapid solidification mechanism of liquid Mo-33.3 at.% Zr peritectic alloy were investigated by electrostatic levitation technique, which attained a maximum undercooling of 387 K (0.16 TL). At its liquidus temperature, the density, surface tension, viscosity and solute diffusion coefficient of this refractory alloy were determined as 8.14 g/cm3, 1.60 N/m, 11.32 mPa·s and 1.41 × 10−9 m2/s, respectively. The primary (Mo) dendrite growth started from multi-point nucleation, while its growth velocity agreed well with the prediction of LKT/BCT dendrite growth theory and reached an upper value of 43 mm/s. The subsequent peritectic transition was characterized by a power-law kinetics relation between the nominal growth velocity of peritectic Mo2Zr phase and peritectic undercooling, displaying a maximum velocity of 46 mm/s. The increase of liquid undercooling facilitated the completion of peritectic transition and refined the microstructure of residual primary (Mo) phase, thus enhancing the Vickers hardness of this alloy gradually up to 1190.9 HV at the maximum undercooling.

Determination of acoustic properties of paraffin oil mixed with activated coal nanoparticles or SPAN80 using only BAW time delay measurement

An important aspect of controlling the properties of liquids relates to their use in modern engines powered by composite materials. In this context, controlling the properties of industrial fluids containing micro- and nanoscale particles is essential. Understanding the temperature-dependent behavior of fluid density and elasticity is crucial for proper engine operation. Seven physical parameters of pure paraffin oil, paraffin oil with varying concentrations of activated coal nanoparticles or sorbitane monooleate (SPAN 80) were simultaneously determined using only BAW time delay measurement in the single experimental run. This technique relies on propagating LBAW through the test fluid and measuring the time delay and amplitude of these waves at different temperatures. By calculating temperature coefficients for velocity, density, time delay, and expansion using well-established formulas the physical properties of fluids under study were determined. The frequency of the LBAW used in the experiment was 13 MHz. The length of the liquid sample in the propagation direction of LBAW was ∼ 5 mm. The experiments were carried out within a temperature range of −20 °C to +90 °C. The volume of the test sample was around 1 milliliter. The comparison of the physical properties of different suspensions under these conditions allows us to demonstrate the dependence of the measured properties on the type and composition of the medium tested.

Droplet-based triboelectric devices using liquid dielectrics for self-powered sensing applications

Triboelectric nanogenerators (TENGs) have attracted great interests by exploiting the complex interplay between contact electrification and electrostatic induction. The versatility of tribo-dielectric materials offers significant advantages for environmentally adaptive device design. In this regard, liquid dielectrics provide intimate contact between filled materials and high dielectric strength. Herein, a liquid dielectric-based TENGs system featuring a charge-transfer liquid layer is presented. A multifaceted summary is presented to illustrate the relationship between liquid dielectric materials and charge transfer mechanisms. New strategies for exploiting the dielectric properties of various liquids to control their electrical properties and monitor the parameters of liquid dielectric properties are highlighted. Additionally, it contributes to the advancement of self-powered sensing technology with increased flexibility, capacitance tuning, and sensor functionality through easy modularization. These achievements contribute to the understanding of charge transfer mechanisms in liquids and highlight their potential for self-powered sensing applications.

Unveiling the interfacial liquid in electrochemical reactions

Adapting novel experimental techniques to address key knowledge gaps about the structure and properties of the interfacial liquid (IL) will enhance our understanding of its influence on electrochemical reactions, particularly in mediating species transport, charge transfer, and intermediate stability.

POWER SUPPLY UNIT OF THE STAND AND LABORATORY INSTALLATION FOR TREATING OLIVES WITH ELECTROSTATIC FIELD

Most technological machines (TM) use hydraulic drives and internal combustion engines, such as lifting and transporting, loading and unloading, construction, road, track, and mining. Increasing the durability of the specified TM units is an urgent task. One of the possible solutions to this urgent problem is the electrostatic treatment of hydraulic oils and diesel fuels. Over the past three decades, researchers have conducted many studies focused on finding optimal means of using external force fields to improve the quality of lubricating materials and intensify their production. Types of influence of force fields, such as mechanical, mechanochemical, acoustic, electromagnetic, and electric, are increasingly used to regulate the behaviour of dispersed particles in nonpolar and slightly polar environments. The theory of regulated interphase transitions proves that the emergence, growth, and size change of supramolecular structures, surrounded by an adsorption-solvate layer and creating complex structural units in oil dispersion systems, contribute to the emergence of new properties of these systems. One of the main provisions of this theory is the need for extreme and antibating changes in the size of complex structural units with the help of external influences, which include force fields. Lubricating materials differ in their degrees of dispersity, composition, and properties, so the effect of force fields on them is diverse. The ability to regulate intermolecular interactions and the size of complex structural units are significant in the operation of lubricants. Electric fields make it possible to control phase interactions in these dispersed systems: they increase the constant dipole moments of particles and the electrosurface forces, which contribute to the deformation of the electric double layer. Under the action of strong electric fields, structural changes occur in hydrocarbon dispersion systems, which significantly change the physicochemical properties of lubricating materials. Thus, the dynamic viscosity of the lubricant and its resistance to deformation may change depending on the chemical nature of the system. Previously conducted experimental studies allow us to formulate the requirements for the stand in detail, which enables investigation of the properties of petroleum-based liquids. Thus, it is possible to achieve increased anti-wear properties of petroleum-based liquids when the liquid passes through the gap between the electrodes in an electrostatic field. The voltage between the electrodes should be U = 1000–1500 V, and the speed of the liquid movement in the space between the electrodes should be V = 4.5–6.5 m/s. The power supply unit of the stand for electroprocessing petroleum-based liquids, proposed in this paper, meets these requirements. The article proposes a fundamentally new scheme for the power supply unit of the laboratory stand for direct current electrotreatment of petroleum-based liquids. The power supply unit is a bipolar source of adjustable direct current. It provides smooth regulation of the voltage from 0 to 3000 V and step regulation of the output current. The block has double protection against short circuits at the output and input. Keywords: anti-wear property, oil, influence of an electrostatic field on the anti-wear properties of oil, device for electrostatic treatment of oil.

Experimental investigation of well deliquification using the partial tubing restrictions

Liquid loading is one of the main challenges in the later life of natural gas wells. Several methods have been tested to remedy this issue and unload gas wells, with various efficiencies. Preliminary studies on the impact of partial restrictions reveals that they improve liquid lifting by generating droplets and preventing the liquid film from falling back. These restrictions are commonly in shape of orifice rings or inserts. This study evaluates liquid unloading by employing such restrictions to improve liquid lifting. The restrictions can be incorporated into the tubing joint design, making them cheaper and easier to install compared to other techniques. Comprehensive experiments are conducted to understand the effect of inserts and liquid properties on two-phase flow behavior. The tests are performed in a 0.0508-m (2-inches) inner diameter vertical flow loop, using water or oil as the liquid phase and air as the gas phase. The tests are conducted with insert opening inner diameters of 0.0381 and 0.0445 m (1.5 and 1.75 inches.)The inserts cause significant mixing and generate high amplitude waves, which facilitate droplet generation. In churn flow with inserts, a thin liquid film is observed traveling downward, while liquid droplets travel upward. The results show that the inserts have the most positive effect at lower gas rates of churn flow and at lower liquid rates. Moreover, inserts provide the largest reduction in the liquid holdup for oil-air flow, due to lower density and surface tension compared to water. The results show that the inserts may enhance the liquid lifting by lowering the liquid holdup, while also increase the pressure drop by increasing the frictional losses. This indicates the need to choose the optimum insert diameter to minimize frictional losses and enhance liquid lifting.

ENSURING ECOLOGICAL AND FIRE SAFETY DURING THE OPERATION OF MOTOR VEHICLES WITH PISTON PNEUMATIC AND CRYO ENGINES WHICH USING THE NITROGEN AS WORKING BODY

In the study, the purpose of which is to improve the mathematical apparatus based on the modified thermodynamic theory of disturbances for describing the thermophysical characteristics of nitrogen in the gaseous and liquid states as the working fluid of fire-safe and environmentally safe motor vehicles with piston pneumatic or cryoengines, a mathematical model was suggested to describe for describing the thermodynamic properties of gaseous and liquid of nitrogen, which is intended for the development of a new type of fire-safe and environmentally efficient vehicle with a piston pneumo- or cryoengine and its application is illustrated. The object of the study is the thermophysical characteristics of nitrogen in a liquid or gaseous aggregate state, as a working fluid of fire-safe and eco-safe motor vehicles with a piston pneumatic or cryoengine. The subject of the research is a mathematical apparatus based on the modified perturbation theory for describing the thermophysical characteristics of nitrogen in gaseous and liquid states. The scientific novelty of the research results is that a mathematical apparatus based on a modified thermodynamic theory of disturbances has been improved for a comprehensive description of all thermophysical characteristics of nitrogen, which is in both liquid and gaseous aggregate state, in terms of reducing calculation time and reducing the error of obtaining thermophysical characteristics compared to reference and experimental data. The practical significance of the research results is that the improved mathematical apparatus is marketable for providing accurate information to the composition of the initial data set in studies on the use of nitrogen in various aggregate states as the working fluid of fire-safe and eco-safe motor vehicles with a piston pneumatic or cryoengine.