Two-component Solutions Research Articles

Anomalous hardening of two-component disordered crystals

The nature of increasing the strength of disordered two-component solid solutions in comparison with materials consisting of atoms of one component is studied. For this purpose, the contribution of extreme fluctuations in the distribution of solution atoms, which create obstacles for the movement of dislocation kinks, is calculated. It is shown that a slow - power - decrease in the probability of large delays on such obstacles leads to anomalous kinetics of kinks. It is accompanied by a slowdown in the movement of dislocations. This may be the reason for the hardening of the material.

Ultrasensitive simultaneous determination of hydroquinone and catechol by Ni3ZnC0.7/Ni porous composites derived from Ni/Zn-MOF

Rational constructing metal–organic frameworks (MOFs) based composite materials with outstanding catalytic capability is vital to accomplish high-performance electrochemical sensors. In this paper, the precursor Ni/Zn-MOF was fabricated by a simple one-step solvothermal method, and then the Ni nanoparticle-supported porous microsphere composites (Ni3ZnC0.7/Ni) were obtained by pyrolysis in N2 atmosphere. The physicochemical characteristics of the as-prepared Ni3ZnC0.7/Ni were studied by XRD, SEM, EDS, TEM, FTIR and XPS, and their electrocatalytic activity were tested by Cyclic voltammetry (CV) and differential pulse voltammetry (DPV). On this basis, an electrochemical sensor strategy for the simultaneous determination of hydroquinone (HQ) and catechol (CC) with Ni3ZnC0.7/Ni modified glassy carbon electrode (GCE) was proposed. In addition, they were applied to the electrochemical simultaneous detection of HQ and CC for the first time. Compared with NiC and ZnC modified electrode, the Ni3ZnC0.7/Ni composites modified electrode can significantly enhance electrocatalytic activity and improve the selectivity and sensitivity of the detection of HQ and CC. The performance was due to increasing the active surface area of the modified electrode and the Ni atom has excellent electrocatalytic capability to dihydroxybenzene. The experimental results exhibits that the composite was used to achieve simultaneous detection of HQ and CC in single-component or two-component solutions with satisfactory result. It has a low limit of detections (LOD = 3σ/k) (HQ: 0.14 μM, CC: 0.21 μM) and a wide detection range (HQ: 0.3–100.0 μM, CC: 0.5–100.0 μM). Meanwhile, the constructed sensor has been successfully employed for determination of HQ and CC in Yellow River water and tap water, and obtains good recovery rate. This work develops a new approach for design and engineering of MOF materials for electrochemical sensors and environmental monitoring.

An Electrochemical Description of 1-Alkyl-3-Methyimidazolium Chloride Ionic Liquids

Three common Ionic Liquids (ILs) were selected 1-Methylimidazolium chloride ([Hmim]Cl), 1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) and 1-Octyl-3-methylimidazolium chloride ([Omim]Cl) for investigation to explore the effects of alkyl chain length and cation protonation on corrosion rate. The aqueous IL solutions have demonstrated a range of identifiably distinct behaviours as a function of changing solution concentration in the range of 70-99.5 mol% water. These behaviours are evidenced by large changes in conductivity, density, and viscosity; these are measurable properties indicating an evolution of hydrogen bonding networks in these systems. These bulk solution properties are critical to the interaction with a metal surface; this was explored using electrochemical testing with Cu and Zn working electrodes. Herein, the focus will be on the use of cyclic voltammetry (at 75 mol%, 85 mol%, 97 mol% and 99.5 mol% water in IL) to describe metal dissolution, deposition, and hydrogen evolution in ILs. The system of equations implemented, to interpret the electrochemical data obtained, have wide-reaching implications in understanding the fundamental behaviours causing observed corrosion behaviours; additionally, the prediction of IL solution conductivity, a vital property for applications of ILs, is of significant value.A kinetic analysis of these solution systems are benefited by the simplicity of the system with no bulk electrolyte, i.e. only the two components: water and IL. Ohmic migration in the bulk and discharge on electrode surface are the two contributions which need to be considered in the Butler-Volmer equation. (n.b. A limitation in the treatment is that thus far no account is taken for the process of solid deposition via a nucleation stage.) In this approximation the following equations can be derived. Each discharging particle must pass two consecutive processes: (1) migration in the field, with characteristic time τohm, and (2) discharge, with the time τBV. The total time will be τtot = τohm + τBV, where τohm -1 = kohm and τBV -1 = kBV. Expressions for Icathodicscan and Ianodicscan results, where φ =E-Ec , for which Ec is the potential at zero current. Two examples are included (Figure 1) to highlight the performance of the models with experimental data. The first case illustrates a particularly good agreement with a cyclic voltammogram experimentally measured for a Cu working electrode in an aqueous-IL solution, the second case is included to demonstrate that the characterstic reversal (near I=0) can be produced. Some deviation, particularly at high current, is likely due to capacitive current. The fitting also gives conductivity, which can be compared and shows good agreement with independent experimental measurements. As such, this successful prediction of the electrochemical behaviours provides an important step in the utilisation of cyclic voltammetry as a method for delivering insight into these two-component IL-containing solutions systems through fundamentally derived expressions. Figure 1

Electrochemical codeposition of La and Fe-group metals in a dicyanamide ionic liquid

Room-temperature electrochemical deposition of lanthanides and their alloys can be achieved employing organic ionic media, such as ionic liquids (ILs). Here, we study the electrochemical (co)deposition of La and Fe-group transition metals from solutions in 1-butyl-1-methyl-pyrrolidinium dicyanamide IL, [BMP][DCA], with controlled water content. We show that electroreduction of La(III) ions starts in the two-component solutions containing La(III) + Me(II) (Me = Co, Fe, or Ni) and no added water in the same potential interval as the electroreduction of respective Me(II). La is thus codeposited with the respective Fe-group metal, as evidenced by voltammetric, microscopic, and X-ray analyses, at considerably more positive potentials than in a solution containing only La(III) ions. Such a promoting effect is not observed in the presence of Cu(I) and Sn(II). Furthermore, the effect of water on the (co)deposition of La and Fe-group metals is systematically investigated. The La-Me (Me = Co, Fe, or Ni) codeposition is inhibited in the presence of moderate amounts of water (up to 0.32 M). At higher water contents, particularly ≥0.32 M H2O in the La(III) + Ni(II) solution, the electroreduction of La starts at more positive potentials than the deposition of Ni. This allows obtaining La-Ni deposits with a high La content. The XPS data indicate that La is present in the deposits in both metallic and oxidized states, even if deposition occurs in a solution with no added water. The results obtained in this study offer valuable insight into the electro(co)deposition of La from IL solutions and contribute to the progress of techniques for producing lanthanide-based functional coatings.

Gelation of Hydrophilic Polymer Bearing Metal-coordination Unit with Various Metal Ions

Abstract Gelation of a hydrophilic polymer bearing a metal-coordination unit with various metal ions was examined. Gels with different morphologies were formed depending on the metal ion species. The formation mechanism for these gels could be explained based on their cross-linking rates. Gelation in two-component solutions containing different ratios of PdII to other metal ions (AuIII and PtIV) was also investigated.

Solitonic attractors in the coupled nonlinear Schrödinger equations with weak dissipations

We use the Lagrangian perturbation method to investigate the properties of soliton solutions in the coupled nonlinear Schrödinger equations subject to weak dissipation. Our study reveals that the two-component soliton solutions act as fixed-point attractors, where the numerical evolution of the system always converges to a soliton solution, regardless of the initial conditions. Interestingly, the fixed-point attractor appears as a soliton solution with a constant sum of the two-component intensities and a fixed soliton velocity, but each component soliton does not exhibit the attractor feature if the dissipation terms are identical. This suggests that one soliton attractor in the coupled systems can correspond to a group of soliton solutions, which is different from scalar cases. Our findings could inspire further discussions on dissipative-soliton dynamics in coupled systems.

Pd(II) and Pt(IV) dispersive or non-dispersive extraction from model and real leach solutions with alkoxyimine-1-propylpyridinium derivatives

The studies present results of Pt(IV) and Pd(II) conventional liquid–liquid extraction and non-dispersive extraction in pseudo-emulsion hollow fiber strip dispersion (PEHFSD) with alkoxyimine-1-propylpyridinium derivatives. Liquid-liquid extraction was used to extract Pd(II) and Pt(IV) both from the model solutions (single and two-component) and from the real solutions, obtained after the leaching PGM from spent automotive catalysts with aqua regia or HCl/H2O2/H2SO4 mixture. The extraction efficiency of Pt(IV) or Pd(II) from one-component solutions with all extractants used (except 4-[1-(2-ethylhexyloxyimine)methyl]-1-propylpyridinium chloride) was high (>90%). However, phase separation took place after 24 h. Also, the coextraction of the H+ ions into the organic phases was observed. It was found that the coextraction of H+ with PGM from one- and two-component model solutions was slight and did not affect the extraction efficiency of PGM. However, for real solutions, the higher the concentration of H+ ions in the feed solution, the stronger the H+ coextraction effect was noted, and resulted in decrease in the extraction efficiency of metal ions from real leach solutions. 3-[1-(decyloxyimine)ethane]-1-propyl-pyridinium chloride (D3EI-PrCl) was found to be asuitable Pd(II) carrier for the liquid membrane technique PEHFSD for the removal of Pd(II) from the Pd(II)/Pt(IV) mixture. The kinetics of the Pd(II) removal depended on the composition of the feed solution; in the presence of Pt(IV), Pd(II) extraction took 2 h, while almost 100% Pd(II) was removed from one-component model solution in 1 h.

Study on electrical double layer nanostructure on zeolitic materials’ surface in the presence of impurities of different nature

The aim of the research was to compare the adsorption mechanisms of heavy metal ions (Pb(II) and Zn(II)), as well as organic substances [diclofenac molecules and pol(acrylic acid) macromolecules on the surfaces of Na-X and Na-P1 synthetic zeolites as well their Na-X© and Na-P1© carbon composites]. The single and mixed adsorbate systems were considered. The more probable structures of the formed adsorption layers were proposed based on the results of the solid surface charge density and zeta potential experiments. The great applicability of the analysis of the parameters characterizing the electrical double layer in determination of the binding mechanism of simple inorganic ions and more complex organic molecules on the surface of the examined solids from the one- and two-component solutions was proved. Moreover, the changes of the surface and electrokinetic factors after the addition of the organic molecules enable specification of drug molecule orientation as well as the polymeric chain conformation at the solid/liquid interface.

Differential Surface Interactions and Surface Templating of Nucleotides (dGMP, dCMP, dAMP, and dTMP) on Oxide Particle Surfaces.

The fate of biomolecules in the environment depends in part on understanding the surface chemistry occurring at the biological-geochemical (bio-geo) interface. Little is known about how environmental DNA (eDNA) or smaller components, like nucleotides and oligonucleotides, persist in aquatic environments and the role of surface interactions. This study aims to probe surface interactions and adsorption behavior of nucleotides on oxide surfaces. We have investigated the interactions of individual nucleotides (dGMP, dCMP, dAMP, and dTMP) on TiO2 particle surfaces as a function of pH and in the presence of complementary and noncomplementary base pairs. Using attenuated total reflectance-Fourier transform infrared spectroscopy, there is an increased number of adsorbed nucleotides at lower pH with a preferential interaction of the phosphate group with the oxide surface. Additionally, differential adsorption behavior is seen where purine nucleotides are preferentially adsorbed, with higher surface saturation coverage, over their pyrimidine derivatives. These differences may be a result of intermolecular interactions between coadsorbed nucleotides. When the TiO2 surface was exposed to two-component solutions of nucleotides, there was preferential adsorption of dGMP compared to dCMP and dTMP, and dAMP compared to dTMP and dCMP. Complementary nucleotide base pairs showed hydrogen-bond interactions between a strongly adsorbed purine nucleotide layer and a weaker interacting hydrogen-bonded pyrimidine second layer. Noncomplementary base pairs did not form a second layer. These results highlight several important findings: (i) there is differential adsorption of nucleotides; (ii) complementary coadsorbed nucleotides show base pairing with a second layer, and the stability depends on the strength of the hydrogen bonding interactions and; (iii) the first layer coverage strongly depends on pH. Overall, the importance of surface interactions in the adsorption of nucleotides and the templating of specific interactions between nucleotides are discussed.

PHYSICOCHEMICAL AND TRIBOLOGICAL PROPERTIES OF AQUEOUS SOLUTIONS OF HYDROLYSATE AND HYDROLYSATE WITH SURFACTANTS AS POTENTIAL LUBRICANT BASES

The study aimed to confirm the hypothesis that aqueous solutions of polymers with surfactants meet the criteria of ecological lubricant bases. An oat hydrolysate was used as the macromolecular substance, and the surfactants were successively: sodium dodecyl sulphate (SDS), Sodium Lauryl Ether Sulfate (SLES), Sodium Lauroyl Sarcosinate (SLS). The research was carried out for two-component solutions (water, hydrolysate) and three-component solutions (water, hydrolysate, surfactant). In order to document this thesis, tribological tests were performed with a constant and increasing load as a function of time. Stationary tests with loads of 2, 3, and 4 kN confirmed the predictions that active substances in two- and three-component solutions create a lubricating film that transfers high loads with relatively low motion and wear resistance. The stability and durability of the lubricating film were confirmed under the conditions of increasing load at a speed of 409 N/s. An approximately 12-fold increase in the seizing load for the hydrolysate solutions in relation to water was found, and the maximum load value for the T02 tester (7200 N) was achieved. The durability of the lubricating film was mainly determined by the adsorption of the hydrolysate, which was confirmed by physicochemical tests.

One-component and two-component Peregrine bump and integrated breather solutions for a partially nonlocal nonlinearity with a parabolic potential

Objective:We establish a projecting transformation from nonautonomous equation into autonomous one, and seek out explicit one-component and two-component solutions of a (2+1)-dimensional coupled nonautonomous nonlinear Schrödinger model for a partially nonlocal nonlinearity with a parabolic potential. Methods:We combine these solutions of autonomous one into the projecting transformation and use the Darboux method to find solutions. Result:We take into account a (2+1)-dimensional coupled nonautonomous nonlinear Schrödinger model for a partially nonlocal nonlinearity with a parabolic potential, and establish a projecting transformation from nonautonomous equation into autonomous one. Moreover, we seek out explicit one-component and two-component solutions, e.g. explicit Peregrine bump solution and explicit integrated breather solutions.

Eclipse timing modelling of three post-common envelope binaries: hybrid solutions

ABSTRACT We report 90 new observations of three post-common envelope binaries at primary eclipse spanning between 2018 December and 2022 February. We combine recent primary eclipse timing observations with previously published values to search for substellar circumbinary components consistent with timing variations from a linear ephemeris. We used a least-squares minimization fitting algorithm weighted by a Hill orbit stability function, followed by Bayesian inference, to determine best-fitting orbital parameters and associated uncertainties. For HS2231+2441, we find that the timing data are consistent with a constant period and that there is no evidence to suggest orbiting components. For HS0705 + 6700, we find both one- and two-component solutions stable for at least 10 Myr. For HW Vir, we find three- and four-component solutions that fit the timing data reasonably well, but are unstable on short time-scales, and therefore highly improbable. Conversely, solutions calculated using a Bayesian orbit stability prior result in a poor fit. The stable solutions significantly deviate from the ensemble timing data in both systems. We speculate that the observed timing variations for these systems, and very possibly other sdB binaries, may result from a combination of substellar component perturbations and an Applegate–Lanza mechanism.

Removal of Heavy Metal Ions from One- and Two-Component Solutions via Adsorption on N-Doped Activated Carbon.

This paper deals with the adsorption of heavy metal ions (Cu2+ and Zn2+) on the carbonaceous materials obtained by chemical activation and ammoxidation of Polish brown coal. The effects of phase contact time, initial metal ion concentration, solution pH, and temperature, as well as the presence of competitive ions in solution, on the adsorption capacity of activated carbons were examined. It has been shown that the sample modified by introduction of nitrogen functional groups into carbon structure exhibits a greater ability to uptake heavy metals than unmodified activated carbon. It has also been found that the adsorption capacity increases with the increasing initial concentration of the solution and the phase contact time. The maximum adsorption was found at pH = 8.0 for Cu(II) and pH = 6.0 for Zn(II). For all samples, better fit to the experimental data was obtained with a Langmuir isotherm than a Freundlich one. A better fit of the kinetic data was achieved using the pseudo-second order model.

Concentration Dependence of the Distance between Different Positions of the Gibbs Dividing Surface in Two-Component Solutions

Concentration Dependence of the Distance between Different Positions of the Gibbs Dividing Surface in Two-Component Solutions

Process development exploiting competitive adsorption-based displacement effects in monoclonal antibody aggregate removal-A new high-throughput screening procedure for membrane chromatography.

High-throughput screening (HTS) approaches are commonly used to accelerate downstream process development. Although most HTS approaches use batch isothermal data (KP screen) or bind and elute mode as screening procedure, different or new process designs are rarely investigated. In this paper, a mechanistic model case study for the separation of two different two-component solutions was conducted and confirmed prior evidence. With these outcomes, a novel HTS screening procedure was developed including the determination of competitive adsorption-based displacement effects and key parameter identification. The screening procedure employing an overload bind and elute (OBE) mode is presented in a case study dealing with IgG aggregate removal in a typical monoclonal antibody purification step, applying a Sartobind®S membrane adsorber (MA). Based on a MA scale down device, the OBE mode allows the determination of classical process parameters and dynamic effects, such as displacement effects. Competitive adsorption-based displacement effects are visualized by introducing a displacement identifier leading to a displacement process map. Based on this map, the approach is transferred to and confirmed by the OBE recycle experiments with 4.6 and 8.2ml benchtop scsale devices resulting in 45% reduced IgG monomer and 88% increased higher molecular weight species binding capacities.

Topology optimization of rigid interlocking assemblies

This paper presents a new density-based topology optimization algorithm for the design of constructible rigid interlocking assemblies with multiple components. The multiple components or structural parts are introduced by having multiple sets of design variables: one for each component. These are filtered separately and combined to create a density field for each structural part. In addition, the framework uses a series of filtering operations to ensure sufficient blocking of rigid body motion and sufficient assemblability. Since this type of assembly is frequently constructed both with and without the use of mortars or adhesives, the structural performance is simplified into a set of static load cases in which the inter-component interactions are estimated. The framework is demonstrated on design examples with two and four components and found to achieve interlocking, constructible assemblies. Crisp interface boundaries and interaction loads along the component interfaces are observed for all examples. Additionally, the two-component solutions are analyzed and compared using computational contact analyses to investigate the influence of the user defined parameters. Finally, an extension is suggested that allows the inclusion of a void phase.

Modulational instability, interactions of two-component localized waves and dynamics in a semi-discrete nonlinear integrable system on a reduced two-chain lattice

In this paper, we investigate a semi-discrete two-component integrable system on zigzag-runged ladder lattice and find a variety of two-component localized waves. First of all, we investigate the modulational instability to reveal the formation mechanism of rogue waves from three distinct plane-wave solutions for this system. Secondly, the discrete generalized -fold Darboux transformation is first constructed to solve this system. As applications, three kinds of plane-wave seed solutions are chosen to exhibit discrete two-component localized wave solutions including rogue wave solutions, breather solutions, periodic wave solutions and interaction solutions. Moreover, the dynamical behaviors of such localized wave solutions are discussed via numerical simulation. Finally, we summarize a few mathematical features to obtain various two-component localized waves through the discrete generalized-fold Darboux transformation. It is found that there are simultaneously bright–dark, dark–bright and bright–bright two-component rogue wave solutions in this discrete two-component system, and moreover, the shapes of bright–dark rogue waves in two components appear alternately with the increase of order number of Darboux transformation when some special seed solutions are selected, which have not been reported before. It is hoped that the results obtained in this paper may be used to understand some related physical phenomena.

Alternative solitons in the Hirota–Satsuma system via the direct method

Multisolitons and multi-hump solitons are constructed for the coupled Korteweg–de Vries (cKdV) system introduced by Hirota and Satsuma (1981) in the context of the propagation of two waves interacting with different dispersion relations. The direct method analytically exhibit a new class of complementary or alternative soliton solutions functionally different to the traditional or classical multisolitons known (Hirota and Satsuma, 1981; Ramani et al., 1983; Parra Prado and Cisneros-Ake, 2020). As in the classical case, our alternative multisolitons are found to obey elastic interactions of the N-KdV and M-cKdV solitons. To show this, we inductively construct tables to describe in detail the mechanism of the different wave interactions and the coefficients involved in them. As a particular scenario, it is found that each of the 1-cKdV and 1-KdV-1cKdV interaction cases may produce two independent criteria for the appearance of one-soliton solutions consisting of two humps in shape. A proper combination of these two conditions gives place to multi-hump solitons. We explicitly show the two-one, two-two, three-one and three-two humps for the two-component wave solutions. • The direct method due to Hirota allows to find complementary two-component multisolitons in a coupled KdV system. • Symmetric one-soliton solutions with two humps in shape are obtained from two independent criteria. • Multi-hump alternative solitons are constructed from two different two-hump conditions.

Mesoscopic structure of mixed type domain walls in multiaxial ferroelectrics

The structure of 180-degree uncharged rotational domain wall in a multiaxial ferroelectric film is studied within the framework of analytical Landau-Ginzburg-Devonshire (LGD) approach. The Finite Element Modelling (FEM) is used to solve numerically the system of the coupled nonlinear Euler-Lagrange (EL) differential equations of the second order for two components of polarization. We show that the structure of the domain wall and corresponding (meta)stable phase of the film are controlled by a single master parameter, dimensionless ferroelectric anisotropy {\mu}. We fitted the static profile of a solitary domain wall, calculated by FEM, with hyperbolic functions for polarization components, and extracted the five {\mu}-dependent parameters from the fitting to FEM curves. The high accuracy of the fitting results allows us to conclude that the analytical functions can be treated as the high-accuracy variational solution of the static EL equations with cubic nonlinearity. We further derive the two-component analytical solutions of the static EL equations for a polydomain 180-degree domain structure in a multiaxial ferroelectric film. The analysis of the free energy dependence on the film thickness and boundary conditions at its surfaces allows to select the domain states corresponding to the minimal energy. The single-domain state is ground for zero polarization derivative at the surfaces, while the poly-domain states minimize the system energy for zero polarization at the surfaces. Counterintuitively, the energy of the polydomain states split into two levels 0 and 1 for zero polarization at the surfaces, and each of the levels is the infinite set of the close-energy sub-levels, which morphology is characterized by different structure of the two-component polarization nodes.

Self-Sustaining Processes of Water Softening and Desalination: Simple Two-Component Systems

Using the method of numerical experiment, the possibility of arranging steady-state self-sustaining processes for softening and desalinating salty water has been studied with use of two-component model solutions containing calcium and sodium ions as an example. In such processes, water softened by ion exchange is subjected to desalination, and the brine formed in this process—without any additional chemicals—is used to regenerate the cation-exchange resin in repeated sorption–desorption cycles. Interest in self-sustaining processes is associated with new technological capabilities for creating a new generation of water-treatment systems, for example, mobile independent units or systems with high degrees of freshwater extraction and brine concentration. The basic foundations of self-sustaining processes are discussed. The ion-exchange dynamics is calculated for many dozens of successive softening–desalination cycles under conditions of varying parameters, such as the ratio of components in the initial solution, the degree of mineralization of such solutions, the degree of concentration of brines, and the composition of desalinated water. The conditions under which the steady-state regimes are formed or not achieved are found.