Typical Liquid Research Articles

Polar Order in a Fluid Like Ferroelectric with a Tilted Lamellar Structure – Observation of a Polar Smectic C (SmCP) Phase

AbstractThe spontaneous polarisation of the SmCP phase is over two orders of magnitude larger than that found in conventional ferroelectric SmC phase of chiral materials used in some LCD devices. Fully atomistic molecular dynamics simulations faithfully and spontaneously reproduce the proposed structure and associated bulk properties; comparison of experimental and simulated X‐ray scattering patterns shows excellent agreement. The materials disclosed here have significantly smaller dipole moments than typical polar liquid crystals such as RM734 which suggests the role of molecular electrical polarity in generating polar order is perhaps overstated, a view supported by consideration of other molecular systems.

Polar Order in a Fluid Like Ferroelectric with a Tilted Lamellar Structure - Observation of a Polar Smectic C (SmCP) Phase.

The spontaneous polarisation of the SmCP phase is over two orders of magnitude larger than that found in conventional ferroelectric SmC phase of chiral materials used in some LCD devices. Fully atomistic molecular dynamics simulations faithfully and spontaneously reproduce the proposed structure and associated bulk properties; comparison of experimental and simulated X-ray scattering patterns shows excellent agreement. The materials disclosed here have significantly smaller dipole moments than typical polar liquid crystals such as RM734 which suggests the role of molecular electrical polarity in generating polar order is perhaps overstated, a view supported by consideration of other molecular systems.

Predicting the entire pyrolysis process of representative charring material infiltrated with kerosene using an improved artificial neural network

It is crucial to predict the entire pyrolysis process of charring materials infiltrated with flammable liquids to provide guidance for reducing the fire hazards and implementing numerical simulations of fire accidents caused by the leakage of flammable liquids. In the present study, pyrolysis data obtained from the thermogravimetric experiments were preprocessed using linear interpolation and data normalization methods. The processed data set was then used to train the artificial neural network (ANN) framework to predict the pyrolysis behaviors of typical charring material (Mongolian Scots pine) infiltrated with typical flammable liquid (kerosene) under three different conditions: (1) pyrolysis at a constant mass fraction of kerosene with multiple heating rates; (2) pyrolysis at multiple mass fractions of kerosene with a constant heating rate; and (3) pyrolysis at multiple mass fractions of kerosene and multiple heating rates. The ANN, with the double hidden layer structure (6−3), was capable to well predict the entire pyrolysis behaviors of Mongolian Scots pine under all the three scenarios. Besides, five data transformation function (multiplication, exponential function with base e, logarithmic function with base e, square root, and exponentiation function) were applied to the present three input variables (temperature, mass fraction of kerosene, and heating rate) to generate new input variables in order to extract more characteristics among the pyrolysis data. Therein, the ANN utilizing the data transformation functions of multiplication and exponential function with base e exhibited the best predictive ability. Among the three input variables in the ANN (temperature, mass fraction of kerosene, and heating rate), temperature was identified as the most sensitive one to the prediction performance, followed by mass fraction of kerosene, with heating rate being the least sensitive.

The effects of aging time on the corrosion inhibition performance of KI and its synergistic effect with a typical phosphorus-based ionic liquid inhibitor

Potassium iodide (KI) is regarded as an ideal synergist for typical corrosion inhibitors. However, the synergistic effect of KI may be compromised due to its oxidation in acidic solutions. In this work, the anticorrosion performance of KI with different aging times in HCl solution and their synergistic effect with dodecyltriphenylphosphonium bromide (C12TPB) were evaluated via electrochemical tests and surface characterization techniques. The corrosion inhibition efficiency of KI gradually increased from 6.41 % to 38.99 % with increasing aging time to 6 h, while the synergy coefficient between KI and C12TPB abnormally decreased from greater than 1.0 to less than 0.4. UV–vis results and quantum chemical calculation demonstrated that the generated I3− during the aging process caused negative impact on the adsorption of C12TPB, leading to the reduced anticorrosion performance. This study provides valuable insights for the rational utilization of KI as the corrosion inhibitor and synergist.

Design and characterization of novel Zr-Al-Fe-Y metallic glasses with nanoscale phase separation

We present a new phase-separated Zr-based metallic glass (MG) composition, free of toxic elements (Ni and Cu) prepared in a glass-forming system by alloying addition. The substitution of Y in Zr70-xAl12.5Fe17.5Yx (x = 0–15 at.%) results in phase separation, giving rise to nano-amorphous domains in a glassy matrix. A homogeneous MG feature is observed for low concentrations of Y up to x = 5. Microstructure and thermal property analysis indicate that the glasses with x = 10 and 15 at.% Y exhibit a typical liquid phase separation-induced two-glassy phase (Zr-rich and Y-rich) with droplet-like microstructures (nano-amorphous domains). With increasing Y addition, the domain size increases. The microstructural evolution arising due to phase separation in these alloys is confirmed by a combination of transmission electron microscopy (TEM) and atom probe tomography (APT) analysis. The formation of nanometer-size Y-enriched clusters is confirmed by APT for x = 15.

Experimental investigation on the vortex-induced vibration response of a lazy-wave flexible riser filled with different fluid media

This paper reports the experimental results of the vortex-induced vibration (VIV) of a lazy-wave flexible riser filled with different fluid media, including the water and helium as typical liquid and light gas examples. The lazy-wave configuration was produced by mounting a buoyancy module of approximately triple the riser diameter on the one-third of the riser length measured from the riser base. The VIV tests were carried out in the depth-averaged reduced velocity (U¯r) range of 9.32–23.19 using the non-intrusive optical measurement with a couple of high-speed cameras. The experimental results indicate that not only the excited mode of in-plane response but also the response amplitude is significantly adjusted when the internal fluid changes, while the excited mode of the out-of-plane response has no obvious modification. Both the water- and helium-filled risers experience the space-varying dominant frequency. However, the helium-filled riser segment possessing a higher dominant frequency is significantly shortened as compared to the water-filled one. When the internal fluid shifts from water to helium, the in-plane mode transition from the first to second becomes incomplete, and the mode transition becomes smoother as U¯r grows. It is found that the starting position of the mode transition is related to the dominant mode as well as the response direction. Then, the influenced length of the riser response from the buoyancy module and the affecting length of the riser on the buoyancy module response are quantified in terms of the spatial distribution of the dominant frequency in comparison with the natural frequencies. The in-plane response of the helium-filled riser is more vulnerable to the oscillation of the buoyancy module, and hence, the coupling between the in-plane and out-of-plane responses is weaker than the water-filled riser. When the impact of buoyancy module on the riser response is enhanced, the reverse effect is weakened.

Development of a high-frequency dielectric spectrometer using a portable vector network analyzer

A simple and novel setup for high-frequency dielectric spectroscopy of materials has been developed using a portable vector network analyzer. The measurement principle is based on radio frequency reflectometry, and both its capabilities and limitations are discussed. The results obtained on a typical liquid crystal prove that the device can provide reliable spectra between 107 and 109 Hz, thus extending the capabilities of conventional impedance analyzers.

Thermoresponsive liquid desiccants for dehumidification cycles

We describe a liquid desiccant dehumidification cycle that regenerates via liquid–liquid phase separation instead of the typical liquid–vapor phase separation. Liquid-liquid phase separation is enabled by the use of thermoresponsive liquid desiccants that exhibit a “U-shaped” immiscibility curve in their phase diagram with water. Crossing this immiscibility curve causes a single-phase liquid to transform into a two-phase liquid mixture, which then facilitates the liquid-state removal of the absorbed humidity. In order to systematically explore this cycle’s dehumidification coefficient of performance (COPdeh), we employ the Flory-Huggins theory of mixing to systematically vary the immiscibility curve. The Flory-Huggins theory uses two key parameters, the lower critical solution temperature (LCST) and the enthalpic interaction parameter (χH) to define the position and shape of the immiscibility curve, respectively. We show that LCST temperatures close to the cycle’s heat rejection temperature improve COPdeh by reducing the necessary sensible heat during regeneration. We also show that enthalpic interaction parameters with larger negative magnitudes lead to flatter immiscibility curves that improve COPdeh. This improves COPdeh by better directing regeneration heat toward liquid–liquid demixing as opposed to increasing temperature. Our modeling indicates that COPdeh values up to ∼4 are possible using this cycle whereas traditional non-thermoresponsive liquid desiccant cycles would achieve COPdeh values of <1. This large increase in COPdeh is due to the fact that the demixing enthalpy associated with liquid–liquid phase separations is much smaller than the enthalpy of vaporization associated with liquid–vapor phase separations.

A sulphide resistant Ag|AgCl reference electrode for long-term monitoring.

Reference electrodes which demonstrate long-term potential stability are essential for many continuous monitoring applications and are commonly based on Ag|AgCl electrodes; however, these electrodes are susceptible to poisoning from aqueous sulphide species which are commonly present in wastewater and natural groundwater. This work presents a sulphide resistant solid-state reference electrode (SSRE) based on a composite material using suspended KCl electrolyte and sacrificial AgCl in a cross-linked polyvinyl acetate polymer matrix. Sulphidation of the sacrificial AgCl produces a stable Ag2S precipitate and prevents further ingress of the poisoning sulphide species through the composite material. A novel SSRE using this material is compared to a control SSRE without suspended AgCl and a typical liquid filled reference electrode. These three reference electrodes are studied using electrochemical impedance spectroscopy (EIS), and their application is also studied in potentiometric pH sensing and cyclic voltammetry (CV). The long-term sulphide resistance of the two SSREs is also studied with potentiometry, and cross-sections of these electrodes were examined using micro X-ray fluorescence (μXRF). Both SSREs demonstrated higher impedance than the liquid reference electrode but were similar to other SSREs reported in the literature. This impedance did not result a meaningful difference in potentiometric pH sensing or CV experiments done using typical scan rates. The KCl/AgCl SSRE exhibited remarkable sulphide resistance, with all samples demonstrating a stable potential without maintenance after ca. 120 days of continuous immersion in 1 g L-1 Na2S solution, whereas KCl SSRE samples all demonstrated significant drift before this time. μXRF sulphur maps revealed that suspended AgCl prevented sulphide ingress, thus protecting the embedded Ag|AgCl electrode. This work presents a reference electrode that could enable long-term monitoring in challenging sulphide solutions, and also highlights a novel approach for preventing reference electrode poisoning which could be more widely explored.

Improved data analysis for molecular dynamics in liquid CCl4

Previously reported inelastic x-ray scattering spectra of a typical van der Waals molecular liquid CCl4 were reanalyzed using a generalized Langevin formalism with a memory function including a thermal and two viscoelastic relaxation processes and simple sparse modeling. The obtained excitations of longitudinal acoustic phonons show a largely positive deviation from the hydrodynamic value by about 57%, much larger than about 37% by the previously reported damped harmonic oscillator result. Such large values of fast sounds in molecular liquids larger than 15-20% of typical liquid metals are interpreted as extra energy losses for terahertz phonons by molecules' vibrational and rotational motions. The rates of the fast and slow viscoelastic relaxations in the memory function at low Q indicate large values, about 0.5 and 2 ps, which correspond to the vibrational and rotational motions of CCl4 molecules, respectively. These values are larger than those of the typical polar molecular liquid acetone, which may reflect the heavier atomic mass of CCl4. The Q dependences of the viscoelastic relaxation rates are discussed in terms of the lifetime and propagating length of the terahertz phonon oscillations. The microscopic kinematic longitudinal viscosity was obtained from the viscoelastic relaxation magnitudes and times, rapidly decreasing with Q from a macroscopic value at Q→0.

The effect of oil-in-water emulsion pesticide on the evolution of liquid sheet rim disintegration and the spraying distribution

Oil-based emulsions often used as agricultural chemical formulations to control pests and weeds. The instability of emulsion spray is an important challenge. In this work, the effects of liquid sheet rim disintegration on spray angle and spraying distribution were studied by visualization method. The results show that the addition of emulsion change the way of rim disintegration and this change may be responsible for the improvement of spray angle and spraying distribution uniformity compared with water spray. In emulsion spray, the typical feature of rim disintegration is the asymmetric “half-moon” shaped holes, which leads to earlier disintegration at the edge of the liquid sheet. The hole coalescence at the rim of liquid sheet may be the reason for the increase of spray angle, because it divides the liquid sheet into small liquid masses and breaks the inward contraction trend of the cohesive attraction of liquid mass. Only 0.02% addition of emulsion, the spray angle could be increased by 8°, the typical liquid sheet breakup length (typical length) and the liquid sheet rim breakup length (rim length) from 23.297 mm to 18.609 mm reduce to 16.3 mm and 9.099 mm, and the spraying distribution curve become more uniform. In addition, the effects of spray structure on spraying distribution characteristics under different concentrations and spray pressures are also discussed. This study could provide a reference for the optimal use of pesticide formulations in the field, the reduction of pesticide waste and environmental pollution, and the establishment of atomization and fragmentation models.

Phenomenological‐based model of direct blue 2 adsorption on corncob in a fixed‐bed

AbstractThis work presents a phenomenologically based semi‐physical model (PBSM) for the liquid–solid adsorption process, which has been experimentally validated. Two modes of operation of adsorption of direct blue 2 dye (DB2) on corn cobs in a fixed bed are discussed by applying the PBSM. The first mode of operation is the typical continuous liquid flow, whereas the second is a semicontinuous mode with the recirculation of liquid leaving the column. These modes of operation were used to illustrate different ways in which the system reaches equilibrium conditions. The equilibrium distribution curve (EDC) for low DB2 concentration was reached with the best fit using the Langmuir–Freundlich model (). The local mass transfer coefficient for the solid phase was evaluated by the PBSM deduction, and subsequently, the diffusivity of the surface solid was experimentally evaluated through comparison in terms of the PBSM. Regardless of the mode of operation, surface diffusion is associated with only the nature of the adsorbent material rather than the concentration of the liquid phase. In addition, the PBSM exhibited liquid and solid concentration changes at different points in the column. Moreover, different operating curves of the process were constructed and validated, exhibiting similar results when comparing the predictions of the model and the experimental data. These findings support the strength of the constructed model, enabling its extension to other adsorbent–dye systems.

Dynamical correlations in simple disorder and complex disorder liquids

Liquids in equilibrium exhibit two types of disorder, simple and complex. Typical simple disorder liquid is liquid nitrogen, or weakly polar liquids. Complex liquids concern those who can form long lived local assemblies, and cover a large range from water to some soft matter and biological liquids. The existence of such structures leaves characteric features upon the atom-atom correlation functions, concerning both atoms which directly participate to these structures and those who do not. The question we ask here is: do these features have also characteristic dynamical aspects, which could be tracked through dynamical correlation functions? Herein, we compare the van Hove function, intermediate scattering function and the dynamical structure factor, for both types of liquids, using force field models and computer simulations. The calculations reveal the paradoxical fact that neighbouring atom correlations for simple disorder liquids relax slower than that for complex disorder liquids, while prepeak features typical of complex disorder liquids relax even slower. This is an indication of the existence of fast kinetic self-assembly processes in complex disorder liquids, while the lifetime of such assemblies itself is quite slow. This is further confirmed by the existence of a very low-k dynamical pre-peak uncovered in the case of water and ethanol.

Impact of Anodic Oxidation Reactions in the Performance Evaluation of High-Rate CO2 /CO Electrolysis.

The membrane-electrode assembly (MEA) approach appears to be the most promising technique to realize the high-rate CO2 /CO electrolysis, however there are major challenges related to the crossover of ions and liquid products from cathode to anode via the membrane and the concomitant anodic oxidation reactions (AORs). In this perspective, by combining experimental and theoretical analyses, several impacts of anodic oxidation of liquid products in terms of performance evaluation are investigated. First, the crossover behavior of several typical liquid products through an anion-exchange membrane is analyzed. Subsequently, two instructive examples (introducing formate or ethanol oxidation during electrolysis) reveals that the dynamic change of the anolyte (i.e., pH and composition) not only brings a slight shift of anodic potentials (i.e., change of competing reactions), but also affects the chemical stability of the anode catalyst. Anodic oxidation of liquid products can also cause either over- or under-estimation of the Faradaic efficiency, leading to an inaccurate assessment of overall performance. To comprehensively understand fundamentals of AORs, a theoretical guideline with hierarchical indicators is further developed to predict and regulate the possible AORs in an electrolyzer. The perspective concludes by giving some suggestions on rigorous performance evaluations for high-rate CO2 /CO electrolysis in an MEA-based setup.

Silica-Based Stationary Phase with Surface Bound N-Acetyl-glucosamine for Hydrophilic Interaction Liquid Chromatography.

A hydrophilic silica-based stationary phase with surface bound N-acetylglucosamine (GlcNAc-silica) was prepared in house and characterized physically via Fourier transform infrared (FTIR) analysis and thermogravimetric analysis (TGA) and chromatographically over a wide range of mobile phase compositions. While both FTIR and TGA confirmed the attachment of the GlcNAc ligands to the silica surface, the chromatographic evaluation of GlcNAc-silica with polar and slightly polar standard solutes (e.g., sugars, nucleic acid fragments, phenolic, and benzoic acid derivatives) yielded the typical hydrophilic interaction liquid chromatography (HILIC) behaviors in the sense that retention increased with increases in solute polarity and the organic content (i.e., acetonitrile) of the hydro-organic mobile phase (i.e., ACN-rich mobile phase). Sugars derivatized with 1-naphthylamine (1-NA) and 2-aminoanthrcene (2-AA) such as xylose, glucose, and short chains maltooligosaccharides constituted the most polar species for HILIC retention evaluation, and in addition, the maltooligosaccharides offered a polar homologous series for gauging the hydrophilicity of GlcNAc-silica in analogy with alkylbenzene homologous series and other nonpolar homologues for evaluating the hydrophobicity of non-polar stationary phases. On the other hand, the benzoic acid and phenolic acid derivatives were the probe solutes for evaluating the HILIC retention dependence of ionizable solutes on the pH of the mobile phase. Similarly, the nucleobase and nucleoside weak basic solutes as well as some typical cyclic nucleotide acidic solutes allowed for the examination of the dependence of solute retention on the pH of the mobile as well as the polarity of the species.

Shackling the aqueous electrolyte via metal-organic frameworks to realize high energy density zinc-ion batteries

Ocean-like free water in conventional aqueous electrolytes leads to narrow operating voltage and parasitic reactions in rechargeable aqueous Zn ion batteries (AZIBs), which is highly undesirable. Herein, a quasi-solid aqueous electrolyte (QSAE) with a typical bulk liquid electrolyte confined inside the sub-nanoscale channels of metal-organic framework (MOFs) is proposed to tackle this issue. Detailed experiments and theoretical calculations suggest that the unfavored side reactions, e.g., corrosion, hydrogen evolution reaction, and dendrite growth on zinc surface can be effectively depressed and the electrochemical window can be expanded to 2.51 V (based on OER), achieved by the proposed MOF-QSAE because of the tailored solvation structure of Zn2+ and the restrained activity of water molecules in MOF-QSAE. Thanks to the unexpected merits of MOF-QSAE, a fabricated Zn|MOF-QSAE|V2O5 full cell exhibits an ultra-high coulombic efficiency (average value≈99.98 %) and cycle stability (capacity retention: 81.89 % after 2000 cycles). The Zn|MOF-QSAE|V2O5 full cell can even work at a low temperature of −10 ℃ for 4000 cycles without obvious performance degradation. In addition, a high-voltage AZIBs based on zinc hexacyanoferrate (ZnHCF) cathode yields an average operating voltage of more than 1.70 V and a high energy density of ≈102 Wh kg−1, further validating the practicality of the MOF-QSAE. The proposed new type of QSAE could pave a new way for the commercialization of aqueous batteries.

Synthesis and mesomorphic properties of novel multi-arm side-chain liquid crystal polymers with different terminal substituents

ABSTRACT In this study, two novel aromatic ester multi-arm liquid crystal monomers M 1 and M 2 with different terminal substituents centred on 3,4,5-trihydroxybenzoic acid, and a rod-shaped chiral liquid crystal monomer N were designed and synthesised. The synthesised liquid crystal monomers M and N were grafted and copolymerised with polymethylhydrosiloxane (PMHS). The structural characterisation of the synthesised liquid crystal compounds was carried out by FT-IR and 1H-NMR. The mesomorphic properties of the synthesised liquid crystal compounds were characterised by POM and DSC, and the results showed that the multi-arm liquid crystal monomers M 1 and M 2 are typical enantiotropic nematic liquid crystal compounds and N is typical thermotropic enantiotropic cholesteric liquid crystal. Polymers P 1 and P 2 are both cholesteric liquid crystal polymers. The glass transition temperatures and liquid crystal isotropic transition temperatures of polymers P 1 and P 2 series both tend to increase with the increase of multi-arm liquid crystal monomer M.

Effect of liquid fuel on foamability and foam stability of mixtures of fluorocarbon and hydrocarbon surfactants

The oil resistivity of aqueous foam is a significant property in many industrial fields. This work aims at studying on oil resistivity of foams generated by mixtures of fluorocarbon and hydrocarbon surfactants, the critical components of firefighting foams. Four kinds of foam solutions were prepared to contain a short-chain fluorocarbon surfactant (FS-50) and four hydrocarbon surfactants with different ionic types, including anionic (SDS), cationic (CTAB), zwitterionic (CAD-40), and nonionic (APG-0810). The effects of the typical liquid fuel (n-heptane) on solution properties, foamability, foam stability, and film stability were studied deeply. The results show that foamability and foam stability were significantly influenced by the addition of n-heptane. The addition of n-heptane leads to significant decrease in foamability of all four foam solutions. The foam volume decay and drainage of all four solutions were accelerated under the action of n-heptane. The film stability of all four solutions decreased upon the presence of n-heptane. The mixture of APG-0810/FS-50 showed the best ability to inhibit liquid fuel. The study can promote the use of mixtures of hydrocarbon and fluorocarbon surfactants in the development of firefighting foams used to extinct liquid fuel fires.

Role of a typical swine liquid manure treatment plant in reducing elements of antibiotic resistance.

Biological treatment of swine liquid manure may be a favorable environment for the enrichment of bacteria carrying antibiotic resistance genes (ARGs), raising the alert about this public health problem. The present work sought to investigate the performance of a swine wastewater treatment plant (SWWTP), composed of a covered lagoon biodigester (CLB) followed by three facultative ponds, in the removal of usual pollutants, antibiotics, ARGs (blaTEM, ermB, qnrB, sul1, and tetA), and intI1. The SWWTP promoted a 70% of organic matter removal, mainly by the digester unit. The facultative ponds stood out in the solids' retention carried from the anaerobic stage and contributed to ammonia volatilization. The detected antibiotic in the raw wastewater was norfloxacin (< 0.79 to 60.55 μg L-1), andthe SWWTP seems to equalize peaks of norfloxacin variation probably due to sludge adsorption. CLB reduced the absolute abundance of ARGs by up to 2.5 log, while the facultative stage does not seem to improve the quality of the final effluent in terms of resistance elements. Considering the relative abundances, the reduction rates of total and ARG-carrying bacteria appear to be similar. Finally, correlation tests also revealed that organic matter and solids control in liquid manure treatment systems could help reduce the spread of ARGs after the waste final disposal.

Synthesis and mesomorphic properties of swallow-tailed liquid crystal monomers and polymers

In this article, we designed and synthesized two novel swallow-tailed liquid crystal monomers (M1 and M2) with different chain lengths and rigidities centered on 3,4,5-trihydroxybenzoic acid and two series of side-chain liquid crystals polymers PN1 and PN2. All liquid crystal monomers and polymers were conformed to the molecular designs by FT-IR and NMR. The liquid crystal properties were tested by DSC and POM, and the results showed that M1 and M2 were thermotropic enantiotropic nematic liquid crystals and the side-chain liquid crystal polymers PN1 and PN2 series were typical amorphous liquid crystal polymers. With the increase of monomer content, the glass transition temperatures and clearing points of PN1 and PN2 series enhanced. With the increase of the number of mesogens in the liquid crystal monomer, the rigidity was enhanced, and the liquid crystal performance of the polymer was better.