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A classical non-polarizable force field for the common halide (F−, Cl−, Br−, and I−) and alkali (Li+, Na+, K+, and Cs+) ions in SPC/E water is presented. This is an extension of the force field developed by Loche et al. for Na+, K+, Cl−, and Br− (JPCB 125, 8581–8587, 2021): in the present work, we additionally optimize Lennard-Jones parameters for Li+, I−, Cs+, and F− ions. Li+ and F− are particularly challenging ions to model due to their small size. The force field is optimized with respect to experimental solvation free energies and activity coefficients, which are the necessary and sufficient quantities to accurately reproduce the electrolyte thermodynamics. Good agreement with experimental reference data is achieved for a wide range of concentrations (up to 4 mol/l). We find that standard Lorentz–Berthelot combination rules are sufficient for all ions except F−, for which modified combination rules are necessary. With the optimized parameters, we show that, although the force field is only optimized based on thermodynamic properties, structural properties are reproduced quantitatively, while ion diffusion coefficients are in qualitative agreement with experimental values. [ABSTRACT FROM AUTHOR]

In this study, we present a new equation of state for electrolyte solutions, integrating the statistical associating fluid theory for variable range interactions utilizing the generic Mie form and binding Debye–Hückel theories. This equation of state underscores the pivotal role of ion–ion association in determining the properties of electrolyte solutions. We propose a unified framework that simultaneously examines the thermodynamic properties of electrolyte solutions and their electrical conductivity, given the profound impact of ion pairing on this transport property. Using this equation of state, we predict the liquid density, mean ionic activity coefficient, and osmotic coefficient for binary NaCl, Na2SO4, and MgSO4 aqueous solutions at 298.15 K. Additionally, we evaluate the molar conductivity of these systems by considering the fraction of free ions derived from our equation of state in conjunction with two advanced electrical conductivity models. Our results reveal that, while ion–ion association has a minimal influence on the modification of the predicted properties of sodium chloride solutions, their impact on sodium and magnesium sulfate solutions is considerably more noticeable. [ABSTRACT FROM AUTHOR]

Building on recent simulation work, it is demonstrated using molecular dynamics simulations of two-component fluid mixtures that the chemical contribution to the Soret effect in two-component nonideal fluid mixtures arises due to differences in how the partial pressures of the components respond to temperature and density gradients. Further insight is obtained by reviewing the connection between activity and deviations from Raoult's law in the measurement of the vapor pressure of a liquid mixture. A new parameter γ s S , defined in a manner similar to the activity coefficient, is used to characterize differences deviations from "ideal" behavior. It is then shown that the difference γ 2 S − γ 1 S is predictive of the sign of the Soret coefficient and is correlated to its magnitude. We hence connect the Soret effect to the relative volatility of the components of a fluid mixture, with the more volatile component enriched in the low-density, high-temperature region, and the less volatile component enriched in the high-density, low-temperature region. Because γ s S is closely connected to the activity coefficient, this suggests the possibility that measurement of partial vapor pressures might be used to indirectly determine the Soret coefficient. It is proposed that the insight obtained here is quite general and should be applicable to a wide range of materials systems. An attempt is made to understand how these results might apply to other materials systems including interstitials in solids and multicomponent solids with interdiffusion occurring via a vacancy mechanism. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate how the ion association constant can be attributed to the difference between the full Poisson–Boltzmann equation and its linearized version in very dilute solutions. We follow a pragmatic approach first by deriving an analytical approximated solution to the Poisson–Boltzmann equation, then calculating its respective Helmholtz free energy and activity coefficient, and then finally comparing it to the contribution from the mass action law principle. The final result is the Ebeling association constant. We conclude that electrostatic ion–ion interaction models miss the ion association contribution naturally introduced in higher-order electrostatic theories. We also demonstrate how the negative deviations from the Debye–Hückel limiting law can be physically attributed to the ion association phenomenon. [ABSTRACT FROM AUTHOR]

This study presents a new equation of state (EOS) for charged hard sphere fluids that incorporates ion-ion association. The EOS is developed using the Debye–Hückel (DH) theory, reference cavity approximation, and Wertheim's theory. Predictive accuracy is evaluated by comparing the model's predictions with Monte Carlo simulations for various charged hard-sphere fluids. The assessment focuses on mean ionic activity coefficient, individual ionic activity coefficient, and osmotic coefficients. The results demonstrate good agreement between the model and simulations, indicating its success for different electrolyte systems. Incorporating ion-ion association improves accuracy compared to the DH theory. The importance of the cavity function and ion-dipole interactions is emphasized in accurately representing structural properties. Overall, the developed EOS shows promising predictive capabilities for charged hard sphere fluids, providing validation and highlighting the significance of ion-ion association in thermodynamic predictions of electrolyte solutions. [ABSTRACT FROM AUTHOR]

Eutectic systems design requires an in-depth understanding of their solid–liquid equilibria (SLE). Modeling SLE in eutectic systems has as prerequisites, the melting properties and activity coefficients of components in the liquid phase. Thus, due to the unavailable melting properties of thermally unstable substances, it is impossible to estimate their activity coefficients from experimental SLE data and model the SLE phase diagram of their eutectic systems. Here, we evaluate the activity coefficients of thermally unstable constituents in the liquid phase, which were calculated independent of their melting properties by correlating the SLE data of their cocrystals. Differential scanning calorimetry and powder x-ray diffraction were employed to obtain the SLE phase diagram of three eutectic systems, i.e., tetramethylammonium chloride/catechol, tetraethylammonium chloride/catechol, and betaine/catechol systems, and identify the formation of nine cocrystals. The non-random, two-liquid equation was used to calculate the activity coefficients of the components in the liquid phase. The substantial negative deviation from ideality in the three studied systems indicated strong hydrogen bonding interactions in the liquid solution. Furthermore, modeling ion–ion interactions in eutectic systems containing ionic constituents is of utmost importance for understanding their nonideality. [ABSTRACT FROM AUTHOR]

The study investigates the solubility of carbon dioxide (CO 2) in three ionic liquids [BMP][Tf 2 N] (1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide), [HMP][Tf 2 N] (1-hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide) and [OMP][Tf 2 N] (1-octyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide). The research is conducted over a temperature range of 303.15 to 363.15 K. The phase equilibria of the binary systems are predicted using the Peng-Robinson (PR) equation of state, the Wilson (WS) mixing rule and the UNIFAC activity coefficient model. The interaction parameter k ij is regressed from the vapor-liquid equilibrium (VLE) experimental data. The study also calculates the excess Gibbs free energy (GE), excess enthalpy (HE), and excess entropy (SE) for these systems. The research results indicate that the length of the alkyl chain in the cation has a significant effect on the excess properties of the CO 2 -ionic liquid systems. As the alkyl chain length increases, the excess Gibbs free energy and excess enthalpy decrease, while the excess entropy increases. The CO 2 -[OMP][Tf 2 N] system exhibits stronger interactions between CO 2 and the ionic liquid, indicating a higher capacity for CO 2 absorption. The study results are helpful for optimization of CO 2 capture processes and the broader comprehension of fluid phase equilibria in complex systems. [ABSTRACT FROM AUTHOR]

[Display omitted] At the interface between an ion-exchange membrane and a multi-electrolyte solution, charged species redistribute themselves to minimize the free energy of the system. In this paper, we explore the Donnan equilibrium of membranes with quaternary electrolyte (Na+/Mg2+/K+/Ca2+/Cl−) solutions, experimentally. The data was used to calculate the ion activity coefficients for six commercial cation-exchange membranes (CEMs). After setting one of the activity coefficients to an arbitrary value, we used the remaining (N-1) activity coefficients as fitting parameters to describe the equilibrium concentrations of (N) ionic species with a mean relative error of 3 %. At increasing solution ionic strengths, the equivalent ion fractions of monovalent counter-ions inside the membrane increased at the expense of the multivalent ones in alignment with the Donnan equilibrium theory. The fitted activity coefficients were employed in a transport model that simulated a Donnan dialysis experiment involving all four cations simultaneously. The arbitrary value assigned to one activity coefficient affects the calculated Donnan potential at the membrane interface. Nevertheless, this arbitrary value does not affect the prediction of the ion concentrations inside the membrane and consequently does not affect the modeled ion fluxes. [ABSTRACT FROM AUTHOR]

Global cashew nut production is nearly 4 million tons per year, valued at 7 billion US dollars. Remarkably, almost the entire cashew apple crop, amounting to 20 million tons annually, goes to waste. However, the cashew apple contains valuable nutraceutical compounds, including tannins, polyphenols, and carotenoids, estimated to be worth 150 million US dollars annually. Due to the highly perishable nature of cashew apples, degradation is a significant issue. In response, the current work has established drying as an effective preservation technique for these bioactive components. The effect of drying temperature on bioactive compounds has been thoroughly investigated. The non‐random two liquid (NRTL) activity coefficient model effectively captures the thermodynamics of the drying process. To facilitate the selection and design of drying equipment, two mechanistic mass transfer models were developed. The first model employs the Maxwell‐Stefan framework to account for internal diffusion, with external mass transfer resistance appearing as a boundary condition. While this model works well for products like grapes, it proved inadequate for explaining the drying behaviour of cashew apples. Consequently, a second model was developed, postulating rapid moisture transport by capillary action within the cashew apple. This model effectively captures the effects of a wide range of operating conditions, using only external mass transfer resistance as the tuneable kinetic parameter. This mechanistic model is more suitable for dryer design compared to conventional phenomenological models like the logarithmic model and the two‐term exponential model. [ABSTRACT FROM AUTHOR]

Nickel tetraphenyl‐porphyrin (NiTPPH₂) and zinc tetra(4‐methophenyl)‐porphyrin (ZnTPPH₂(p‐methyl)) were successfully synthesized and characterized using 1H NMR spectroscopy. Their antioxidant activities and interactions with the superoxide anion radical (O2•_) were evaluated using cyclic voltammetry. Remarkably, NiTPPH₂ displayed superior antioxidant activity with an IC50 value of 54.57 μg mL−1, significantly outperforming α‐tocopherol (IC50 = 353.27 μg mL−1), indicating its potential as a potent antioxidant. Binding free energy calculations demonstrated that electrostatic interactions predominantly govern the binding, with values of −23.47 kJ mol−1 for NiTPPH₂ and −22.50 kJ mol−1 for ZnTPPH₂(p‐methyl). These values suggest robust binding affinities with O2•_. Quantum chemical parameters, obtained through density functional theory (DFT), showed a strong correlation with experimental results, validating the computational approach. Additionally, ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) and drug‐likeness assessments, alongside molecular docking studies, highlighted favorable pharmacokinetic profiles and binding affinities. These findings underscore the potential of NiTPPH₂ and ZnTPPH₂(p‐methyl) as promising candidates for antioxidant therapy, exhibiting drug‐like properties and favorable pharmacokinetics. This research advances the understanding of these porphyrin derivatives and their application in the development of novel antioxidant therapeutics. [ABSTRACT FROM AUTHOR]

The esterification of 1-methoxy-2-propanol (PM) and acetic acid (AA) is an important reaction for the production of 1-methoxy-2-propyl acetate (PMA). Herein, we used the macroporous ion-exchange resin Amberlyst-35 as a catalyst to explore the effects of reaction conditions on the reaction rate and equilibrium yield of PMA. Under the optimized conditions of a reaction temperature of 353 K, using the initial reactant PM/AA with a molar ratio of 1:3, and a catalyst loading of 10 wt%, the PMA equilibrium yield reached 78%, which is the highest equilibrium yield so far. The reaction equilibrium constants and activity coefficients were estimated to obtain reaction thermodynamic properties, indicating the exothermicity of the reaction. Furthermore, pseudo-homogeneous (PH), Eley–Rideal (ER), and Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic models were fitted based on experimental reaction kinetic data. The results demonstrate that the LHHW model is the most consistent with experimental data, indicating a surface reaction-controlled process and exhibiting an apparent activation energy of 62.0 ± 0.2 kJ/mol. This work represents a valuable example of calculating reaction thermodynamics and kinetics, which are particularly essential for promising industrial reactor designs. [ABSTRACT FROM AUTHOR]

In this work, thermodynamic properties of ternary (NaNO3 + DMF + water) system were reported using the potentiometric method. The electromotive force measurements were performed on the galvanic cell of the type: NO 3 - ISE NaNO 3 m , DMF w % , H 2 O (1 - w) % Na - ISE , in various mixed solvent systems containing 0, 5, 10, 15 and 20% mass fractions of DMF over total ionic strengths from 0.0100 to 2.500 mol·kg−1 at T = (298.2, 303.2 and 308.2) K and P = 0.1 MPa. The experimental activity coefficients of NaNO3 were analysed using extended Debye–Hückel equation, Pitzer ion interaction model and Scatchard equation. The Pitzer adjustable parameters were used to calculate γ ± , φ , G E / nRT , H E / nRT and S E / nR . Also, Scatchard parameters were used to calculate γ N 2 / γ N 1 for the whole series of under investigation system. [ABSTRACT FROM AUTHOR]

• The solubility of R1234ze(E) and R1336mzz(E) in two lubricants was tested and compared. • Experimental solubility data were correlated by the NTRL activity coefficient model. • The Henry's constants of R1234ze(E) and R1336mzz(E) in PAG and POE were obtained. Trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) and trans-1,1,1,4,4,4-hexafluorobut-2-ene (R1336mzz(E)) are environmentally friendly working fluids with low global warming potential (GWP) that can be used in compression refrigeration and heat pump systems. In this study, a solubility measurement system was established to assess the solubility of R1234ze(E) and R1336mzz(E) in polyalkylene glycol ether (PAG) and polyol ester (POE) at temperatures (283.15–323.15 K). The Henry's constants for four binary systems R1234ze(E)/PAG, R1336mzz(E)/PAG, R1234ze(E)/POE, and R1336mzz(E)/POE were analyzed and compared. Additionally, The non-random two liquid (NRTL) activity coefficient model was applied to correlate the solubility data in this study. The results indicate that R1234ze(E) exhibits higher solubility in PAG lubricant, while R1336mzz(E) is more easily dissolved in POE lubricant. Moreover, the solubility of R1336mzz(E) in both PAG and POE lubricants shows greater sensitivity to pressure and temperature changes compared to R1234ze(E). The results reported in this study can serve as a valuable guide for the choice of suitable lubricants for R1234ze(E) and R1336mzz(E) in different applications. [ABSTRACT FROM AUTHOR]

The efficient delivery of nicotine in e-cigarette aerosols depends on the deposition efficiency of these aerosols within the respiratory tract. Accurate prediction of the hygroscopic growth of e-cigarette aerosols is pivotal to understanding their deposition. This study introduces a novel experimental approach to quantify the water activity coefficient, which is a crucial parameter governing the extent of hygroscopic growth in e-cigarette aerosols. Propylene glycol (PG) and vegetable glycerin (VG) are the primary components of e-liquid so that are used as the experimental subjects. Our findings reveal intriguing trends in the behavior of PG and VG mixtures. As relative humidity (RH) increases, these mixtures exhibit elevated equilibrium mass fractions of water accompanied by a decrease in water activity coefficients. Moreover, higher initial PG/VG mass ratios lead to decreased mass fractions of water and increased water activity coefficients. Notably, solution pH also impacts water activity coefficients, with higher pH levels corresponding to increased coefficients. The results reveal the factors which can affect the hygroscopic growth of e-cigarette aerosols, thus contributing to the understanding of the deposition of such aerosols within the respiratory tract. Moreover, the experimental apparatus proposed in this study provides a straightforward and reliable method to obtain hygroscopic parameters of multicomponent solutions. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

The titanium distribution ratio ( L Ti ) between ferrosilicon (FeSi) melt and the CaO-SiO2-Al2O3 slag was measured at 1773 K (1500 °C). FeSi-slag equilibration was carried out using various slag compositions. The L Ti was presented against the Vee ratio (pct CaO/pct SiO2 = C/S) between 0.3 and 1.2, and Al2O3 content from 5 to 20 mass pct. The L Ti exhibited minima at about C/S=0.7(±0.1) at a fixed Al2O3 content. In a C/S < 0.7 regime, i.e., relatively acidic melts, Ti4+ ions were considered as network forming [TiO4]-tetrahedron unit in the aluminosilicate framework. However, in a C/S > 0.7 regime, i.e., relatively basic melts, Ti4+ ions were considered to form the [TiO5]-pyramid structure unit compensated by Ca2+. When adding Al2O3 into the basic melts over 10 mass pct, [AlO4]-tetrahedrons take Ca2+ ions for charge compensation, resulting in a decrease of stability of [TiO5] unit because of Ca2+ depletion. At a greater than 10 mass pct Al2O3 content in the basic melts, Ti4+ replaced Al3+ to form the [TiO4]-tetrahedron unit, decreasing the activity coefficient of TiO2 in the slag. [ABSTRACT FROM AUTHOR]

Background: Although standard operational procedures for pre‐therapeutic dosimetry already exist for the determination of the maximum safe activity to treat differentiated thyroid cancer patients, empiric activity administration of 131I is still the most frequent way of treatment. In this way, the absorbed dose to the blood/bone marrow remains unknown. Purpose: In this work, we present a strategy to estimate radiation dose to the blood in an outpatient setting. Methods: A mobile application was developed, which together with an off‐the‐shelf compact semiconductor radiation detector allows the determination of whole‐body time‐integrated activity coefficients. The methodology was tested in a cohort of 79 differentiated cancer patients who received therapeutic 131I activities. Post‐therapeutic whole‐body time‐integrated activity coefficients were compared against pre‐therapeutic estimates in a subset of 13 patients. Results: The 95% limits of agreement between pre whole‐body and post whole‐body time integrated activity coefficients were [‐14.4; 6.6] h when considering outliers and [‐6.2; 3.6] h without outliers. A high dispersion in blood dose coefficients was found, with a four‐fold difference between the highest and lower values. Blood doses were significantly higher for patients treated with dosimetrically guided activities than for empirical activities (median dose = 118 vs. 49 cGy, respectively). Blood dose coefficients were significantly lower for patients prepared with recombinant human thyroid stimulating hormone (rhTSH) than for patients prepared with thyroid hormone withdrawal. A low correlation between blood dose and administered activity was found in empirically treated patients (R2 = 0.26). Conclusions: We successfully implemented a post‐therapeutic internal dosimetry methodology for differentiated thyroid cancer therapy with 131I, which allows to estimate dose to the blood from outpatient measurements with mobile devices. The proposed methodology avoids the need of daily visits to the nuclear medicine department, thus reducing the burden for the patient and for the staff. [ABSTRACT FROM AUTHOR]

In this work, we aim to explore new exact traveling wave solutions for the reaction–diffusion equation, which describes complex nonlinear phenomena such as cell growth and chemical reactions in nature. Obtaining exact solutions to this equation is crucial for understanding aspects such as reaction activity and the diffusion coefficient. We solve the reaction–diffusion equation by using the Riccati equation as an auxiliary equation. By controlling the parameters in the Riccati equation, we obtained a large number of traveling wave solutions, many of which were not formerly recorded in other documents. Numerical simulations demonstrate the evolution of various traveling waves of the reaction–diffusion equation in time and space. These rich exact solutions and wave phenomena help to expand our knowledge of this equation. [ABSTRACT FROM AUTHOR]

Three new binary acidic deep eutectic solvents (DESs) were derived from tetrabutylammonium bromide (TBAB) as a hydrogen bond acceptor (HBA) coupled with azelaic acid (AzA), benzilic acid (BeA) and boric acid (BoA) as hydrogen bond donors (HBD). In order to draw the complete phase diagram and find the molar ratios in which the DESs are formed, HBA and HBDs were mixed together in the full range of molar ratios and their thermal behavior (by differential scanning calorimetry method) and stability were investigated. The activity coefficient models including Wilson, NRTL and regular solution were applied to correlate the measured solid–liquid equilibrium data. FT–IR and NMR analysis were used to investigate the chemical structures, occurrence the hydrogen bond formation between the DESs constituents and purity of the prepared DESs. Physicochemical properties of these DESs including melting point, density, and speed of sound, conductivity and refractive index were measured at different temperatures. The performance of these new DESs were successfully evaluated for the dissolution of four metal oxides including PbO, CuO, Fe2O3 and ZnO and the obtained solubility values were compared with the reported literature data. [ABSTRACT FROM AUTHOR]

• The performance of AHTs using {H 2 O+ILs} working pairs are evaluated. • Simulated the performance of ILs in AHTs under high heat source temperature. • {H 2 O+ILs} working pairs can achieve greater temperature lift compared to {H 2 O+LiBr}. • The exergy loss of {H 2 O+LiBr} in each component of AHT is lower than {H 2 O+DMIMDMP}. The study investigated six sets of ionic liquid (IL) working pairs based on high-temperature vapor-liquid equilibrium data. These sets were modeled using the NRTL activity coefficient model and integrated into a single-stage absorption heat transformer (AHT) for system cycle simulation analysis. A comparison was made with traditional H 2 O + LiBr working pairs commonly used in AHTs. The study aimed to assess the feasibility of using IL working pairs in high-temperature AHTs to achieve higher output temperatures when dealing with heat sources exceeding 120 °C. Compared to the traditional H 2 O + LiBr working pair, which has strong COP and ECOP but a limited temperature range, IL pairs offer advantages under various conditions. For instance, H 2 O + [HMIM][Cl] and H 2 O + [BMIM][Br] can operate at higher condensation temperatures, providing broader temperature ranges. H 2 O + [HMIM][Cl] has a wider operational temperature range, suitable for unstable waste heat sources. It also has the highest optimal ECOP value of 0.64 at 197 °C absorption temperature, and shows good cyclic performance, achieving temperature rises of about 78 °C. ILs can maintain stable COPs and circulation ratios over a wide range of absorption temperatures, thus achieving higher temperature rises or meeting the need for higher absorption temperatures. Notably, although the H 2 O + IL combination exhibits slightly higher exergy loss than the traditional H 2 O + LiBr pair when comparing exergy losses in the AHT system among different working pairs, its low corrosiveness, lack of crystallization, and wide operating temperature range make these drawbacks insignificant. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the dose in different protocols of 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (PET/CT) procedure. The retrospective study involves 207 patients with confirmed malignancies who underwent PET/CT. Effective dose (E) from PET was estimated based on injected activity and dose coefficient as per International Commission on Radiation Protection (ICRP) 128. Estimation of E from CT was done utilizing the dose length product (DLP) method and conversion factors as per ICRP 102. There was a significant statistical difference observed in E between different PET/CT protocols (P <.001). E of PET in the whole body (WB) was found to be 4.9 ± 0.9 mSv, whereas mean volume computed tomography dose indexvol, DLP, and E of CT in WB were 7.0 ± 0.2 mGy, 674.3 ± 80.7 mGy.cm, and 10.1 ± 1.2 mSv, respectively. No linear correlation was seen between the size-specific dose estimate and E of CT (r  = −0.003; P =.978). The total mean E in WB PET/CT was 17.0 ± 1.7 mSv. CT dose was contributing more than PET dose in all protocols except brain PET/CT. Optimization strategies can be evaluated only if monitored periodically. [ABSTRACT FROM AUTHOR]

A new separation technology, three-phase crystallization (TPC), was utilized to purify acrylic acid (AA) from a binary liquid mixture comprising AA and propionic acid (PA). The solid–liquid equilibrium data of AA/PA mixture reported in the literature were adopted to recover the activity coefficients of the liquid mixture; and, subsequently, the vapor–liquid equilibrium conditions of AA/PA mixture were predicted using Raoult's law and the Wilson equations for the recovered activity coefficients. The reported solid–liquid equilibrium data and the predicted vapor–liquid equilibrium conditions were coupled to determine the three-phase transformation conditions of AA/PA mixture, which were employed to conduct the batch TPC experiments. Upon conclusion of the TPC, the yield and purity were measured to estimate the amount of the AA crystals and volume of the liquid mixture retained in the overall final product, respectively. [ABSTRACT FROM AUTHOR]

A leading cause of global warming is the increase of carbon dioxide (CO2) emissions due to anthropogenic activities which prompts an urgent need for substantial reduction. Recently, CO2 absorption in deep eutectic solvents (DESs) has attracted scientific attention, because of their adaptability compared to traditional ionic liquids and aqueous amine solutions. This study employs the heating method to synthesize DESs using tetrapropylammonium bromide (TPAB) and formic acid (Fa) with molar ratios of TPAB-Fa (1:1) and TPAB-Fa (1:2). Absorption experiments by static method quantified CO2 solubility in the DESs under varied pressures and temperatures. TPAB-Fa (1:2) at 25.0 °C was the most efficient with the CO2 solubility of 0.218. Thermodynamic modeling was performed by employing the nonrandom two liquids activity coefficient model and the Peng–Robinson equation of state for the liquid and gas phases, respectively. The Henry's law constant was determined from experimental data. CO2 physical absorption was confirmed via nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) analyses. TPAB-Fa (1:2), as the superior DES, exhibited regeneration efficiency of 99% after five absorption/desorption cycles. [ABSTRACT FROM AUTHOR]

Background: Subtraction of single-photon emission computed tomography (SPECT) images has a number of clinical applications in e.g. foci localization in ictal/inter-ictal SPECT and defect detection in rest/stress cardiac SPECT. In this work, we investigated the technical performance of SPECT subtraction for the purpose of quantifying the effect of a vasoconstricting drug (angiotensin-II, or AT2) on the Tc-99m-MAA liver distribution in hepatic radioembolization using an innovative interventional hybrid C-arm scanner. Given that subtraction of SPECT images is challenging due to high noise levels and poor resolution, we compared four methods to obtain a difference image in terms of image quality and quantitative accuracy. These methods included (i) image subtraction: subtraction of independently reconstructed SPECT images, (ii) projection subtraction: reconstruction of a SPECT image from subtracted projections, (iii) projection addition: reconstruction by addition of projections as a background term during the iterative reconstruction, and (iv) image addition: simultaneous reconstruction of the difference image and the subtracted image. Results: Digital simulations (XCAT) and phantom studies (NEMA-IQ and anthropomorphic torso) showed that all four methods were able to generate difference images but their performance on specific metrics varied substantially. Image subtraction had the best quantitative performance (activity recovery coefficient) but had the worst visual quality (contrast-to-noise ratio) due to high noise levels. Projection subtraction showed a slightly better visual quality than image subtraction, but also a slightly worse quantitative accuracy. Projection addition had a substantial bias in its quantitative accuracy which increased with less counts in the projections. Image addition resulted in the best visual image quality but had a quantitative bias when the two images to subtract contained opposing features. Conclusion: All four investigated methods of SPECT subtraction demonstrated the capacity to generate a feasible difference image from two SPECT images. Image subtraction is recommended when the user is only interested in quantitative values, whereas image addition is recommended when the user requires the best visual image quality. Since quantitative accuracy is most important for the dosimetric investigation of AT2 in radioembolization, we recommend using the image subtraction method for this purpose. [ABSTRACT FROM AUTHOR]

4-[(S)-2-Methyl-3-hydroxypropyloxy]-4'-formylazobenzene, 4-(3-hydroxypropyloxy)-4'-formylazobenzene and µ-oxodimer of iron 2,8,12,18-tetramethyl-3,7,13,17-tetra-n-amylporphine were synthesized using known methods. A mixture with a certain concentration of components was prepared from the synthesized compounds. The resulting mixture was used as an impregnation of the wide-porous adsorbent Chromaton N-AW. The degree of impregnation was 10%. The prepared adsorbent was used as a stationary phase for inverse gas-mesophase chromatography. In this work, the sorption redistribution of a number of volatile organic compounds—isomers of methyl and dimethylpyridines, weakly polar xylenes and enantiomers from the gas phase on the prepared adsorbent was studied using inverse gas chromatography. During the experiment, the specific retention volumes of sorbates, characterizing the sorption activity of the prepared stationary phase were calculated. For structural isomers, activity coefficients for the distribution of sorbates in the liquid layer of the liquid crystal were obtained. To confirm the data on the sorption activity of sorbates, the thermodynamic parameters of the dissolution of specific isomers were found. Conclusions were drawn about the influence of enthalpy and entropy factors on the retention ability of sorbates. The influence of structure, isomerism, intermolecular interactions, and the addition of a macrocycle on the sorption properties of sorbates is discussed. Data on the analytical features of sorption were obtained, namely, the maximum values of separation factors for structural and optical isomers and compounds of different structures, but with similar boiling points, were calculated. It was experimentally established that the prepared adsorbent exhibits a fairly high ability to separate close-boiling structural isomers and a moderate ability to separate enantiomers. Emphasis is placed on the maximum value of the separation factor of 3,4- and 3,5-lutidines, which is the highest in value among the previously developed stationary phases of similar structure. In conclusion, the use of the resulting adsorbent in a unified system of chemical analysis is justified. [ABSTRACT FROM AUTHOR]

Citrus medica L. is a traditional citrus fruit that is rich in bioactive compounds and has the potential to be used as a natural source of food additives. This study aims to evaluate the antioxidant capacity and characterize the phenolic compounds present in the peels (including flavedo and albedo), pulp, and seeds of citron. The results showed that, compared to the other parts, the pulp had a substantially higher Antioxidant Activity Coefficient (AAC) of 168.2. The albedo and the seeds had significantly lower AAC values, while the green and yellow flavedo showed noteworthy results. O-coumaric acid was the predominant phenolic acid in all of the citron fractions; it was found in the highest concentration in albedo (37.54 µg/g FW). Flavanones and flavanols were the primary flavonoids in the pulp, peel, and seeds, with total flavonoid concentration ranging from ~9 µg/g FW in seeds to 508 µg/g FW in the pulp. This research offers significant insights into the antioxidant properties of this ancient fruit, emphasizing its potential applications as a natural source of antioxidants to be used in different applications. [ABSTRACT FROM AUTHOR]

Delta-like ligand 3 (DLL3) is aberrantly expressed on the surface of small-cell lung cancer (SCLC) and neuroendocrine prostate cancer cells. We assessed the safety and feasibility of the DLL3-targeted imaging tracer [89Zr]Zr-DFO-SC16.56 (composed of the anti-DLL3 antibody SC16.56 conjugated to p-SCN-Bn-deferoxamine [DFO] serving as a chelator for zirconium-89) in patients with neuroendocrine-derived cancer. We conducted an open-label, first-in-human study of immunoPET-CT imaging with [89Zr]Zr-DFO-SC16.56. The study was done at Memorial Sloan Kettering Cancer Center, New York, NY, USA. Patients aged 18 years or older with a histologically verified neuroendocrine-derived malignancy and an Eastern Cooperative Oncology Group performance status of 0–2 were eligible. An initial cohort of patients with SCLC (cohort 1) received 37–74 MBq [89Zr]Zr-DFO-SC16.56 as a single intravenous infusion at a total mass dose of 2·5 mg and had serial PET-CT scans at 1 h, day 1, day 3, and day 7 post-injection. The primary outcomes of phase 1 of the study (cohort 1) were to estimate terminal clearance half-time, determine whole organ time-integrated activity coefficients, and assess the safety of [89Zr]Zr-DFO-SC16.56. An expansion cohort of additional patients (with SCLC, neuroendocrine prostate cancer, atypical carcinoid tumours, and non-small-cell lung cancer; cohort 2) received a single infusion of [89Zr]Zr-DFO-SC16.56 at the same activity and mass dose as in the initial cohort followed by a single PET-CT scan 3–6 days later. Retrospectively collected tumour biopsy samples were assessed for DLL3 by immunohistochemistry. The primary outcome of phase 2 of the study in cohort 2 was to determine the potential association between tumour uptake of the tracer and intratumoural DLL3 protein expression, as determined by immunohistochemistry. This study is ongoing and is registered with ClinicalTrials.gov , NCT04199741. Between Feb 11, 2020, and Jan 30, 2023, 12 (67%) men and six (33%) women were enrolled, with a median age of 64 years (range 23–81). Cohort 1 included three patients and cohort 2 included 15 additional patients. Imaging of the three patients with SCLC in cohort 1 showed strong tumour-specific uptake of [89Zr]Zr-DFO-SC16.56 at day 3 and day 7 post-injection. Serum clearance was biphasic with an estimated terminal clearance half-time of 119 h (SD 31). The highest mean absorbed dose was observed in the liver (1·83 mGy/MBq [SD 0·36]), and the mean effective dose was 0·49 mSv/MBq (SD 0·10). In cohort 2, a single immunoPET-CT scan on day 3–6 post-administration could delineate DLL3-avid tumours in 12 (80%) of 15 patients. Tumoural uptake varied between and within patients, and across anatomical sites, with a wide range in maximum standardised uptake value (from 3·3 to 66·7). Tumour uptake by [89Zr]Zr-DFO-SC16.56 was congruent with DLL3 immunohistochemistry in 15 (94%) of 16 patients with evaluable tissue. Two patients with non-avid DLL3 SCLC and neuroendocrine prostate cancer by PET scan showed the lowest DLL3 expression by tumour immunohistochemistry. One (6%) of 18 patients had a grade 1 allergic reaction; no grade 2 or worse adverse events were noted in either cohort. DLL3 PET-CT imaging of patients with neuroendocrine cancers is safe and feasible. These results show the potential utility of [89Zr]Zr-DFO-SC16.56 for non-invasive in-vivo detection of DLL3-expressing malignancies. National Institutes of Health, Prostate Cancer Foundation, and Scannell Foundation. [ABSTRACT FROM AUTHOR]

In this study, we consider the connection of the hydrodynamic force with vortex shedding behind a stationary sphere in an unbounded fluid at several Reynolds numbers, covering the range of critical transition from plane-symmetric to non-symmetric flow. A principal spectrum analysis (PSA) is employed/proposed to obtain the spectral representation (SR) modes for each time-varying force coefficient; this enables us to identify (i) one single characteristic frequency at R e = 300 , 350, and 380, i.e., the fast frequency f V S which represents the frequency of vortex shedding and (ii) two characteristic frequencies at R e = 390 , 400, and 420: one is the first fast frequency f 1 = f V S , representing the frequency of vortex shedding, and the other is the second fast frequency f 2 , representing the frequency of side oscillations of the vortex flow in the transverse flow direction. In the situations of the latter set of Reynolds numbers, the SR modes indicate that not only the strength but also the phase of shed vortex varies slightly at each successive vortex shedding, and most notably, we have identified rotation of the vorticity pattern in the near wake about the central axis. The PSA-SR mode analysis reveals that these three vortex activities all co-operate at the integer multiples of the greatest common-divisor of the two characteristic frequencies ( f 1 , f 2 ). In other words, the intricate subtlety of vortex shedding behind a stationary sphere can well be uncovered through the PSA-SR mode analysis for establishing the close connections between the force coefficients and the vorticity activities behind the sphere. The present work represents a sequel to our previous study: A spectral force representation and its physical implication for vortex shedding past a stationary or an oscillating circular cylinder at low Reynolds numbers [Lu et al., "A spectral force representation and its physical implication for vortex shedding past a stationary or an oscillating circular cylinder at low Reynolds number," Phys. Fluids 35(5), 053606 (2023)], where we initially proposed the PSA-SR analysis to establish the connections between the force coefficients and the vortex shedding of the circular cylinder under pre-, sub-, and normal synchronization. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the phase behavior of glycerol, 1,2-propanediol, water, and nicotine in heated cigarettes, and explore the influence of temperature and composition (in mole fractions) on the release of nicotine during vaporization. Conductor-like Screen Model for Segment Activity Coefficient (COSMO-SAC) was employed to study the vapor-liquid phase equilibria of ternary and quaternary systems composed of glycerol, 1,2- propanediol, water, and nicotine. For the glycerol-1,2-propanediol-nicotine system, an increase in glycerol mole fraction in the liquid phase promotes the release of nicotine during vaporization. Lower temperatures are more favorable for the vaporization of nicotine. For the glycerol-water-nicotine system, the variation of glycerol composition over a certain range does not significantly change the gas phase composition. Only when the mole fraction of glycerol exceeds 0.9, lower temperatures are more favorable for the vaporization of nicotine. For the water-1,2-propanediolnicotine system, lower temperatures are more favorable for the vaporization of nicotine when the mole fraction of water is less than 0.3 or greater than 0.7. For the water-1,2-propanediol-glycerol-nicotine system, the change of liquid phase composition over a wide range does not significantly change the gas phase composition, that is, the gas phase composition has a wide platform region. [ABSTRACT FROM AUTHOR]

Absolute qualifications with the application of protic ionic liquids (PILs) and a recognition of the numerous thermophysical features of these materials are required in various processes. Due to the wonderful applications of these compounds and their high potential in the chemical and pharmaceutical industries, there is a particular eagerness to utilize these PILs in drug solubility and delivery area. The aim of this investigation was to explore the solubility of the acetaminophen (ACP) in three PILs base on ethanolamine laurate [(2-hydroxyethylammonium laurate [MEA]La), (bis(2-hydroxyethyl)ammonium laurate [DEA]La), and (tris(2-hydroxyethyl)ammonium laurate [TEA]La)]. The shake flask method has been employed in this study, and the conditions were set at T = (298.15–313.15) K and atmospheric pressure. Moreover, the experimental solubility data was correlated using a variety of empirical and thermodynamic models, encompassing e-NRTL and Wilson activity coefficient models and the empirical models such as Van't Hoff-Jouyban-Acree and Modified Apelblat-Jouyban-Acree. Their performance for the system containing [MEA]La follow the trend for activity coefficient models and empirical respectively: the Wilson > e-NRTL and Modified Apelblat–Jouyban–Acree > Van't Hoff–Jouyban–Acree. On the other hand, [DEA]La and [TEA]La PILs followed slightly different trend for activity coefficient models and empirical respectively: the Wilson > e-NRTL and Van't Hoff–uyban–Acree > Modified Apelblat–Jouyban–Acree. The Van't Hoff and Gibbs equations were used to determine the thermodynamic properties of dissolution in the studied systems. [ABSTRACT FROM AUTHOR]

Although the system water + n-propanol + toluene is important for research and industry, its liquid–liquid equilibria LLE are scarcely covered in literature, with no thermodynamic modeling reported using typical equations of state or activity coefficient models. The current work addresses this gap by presenting the equilibria of the system at 20°C and atmospheric pressure. That includes the binodal curve and twelve tie lines covering the entire miscibility gap, whereby the compositions of the conjugate phases are determined using high-precision refractive index measurements. The quality of the data is verified by applying the techniques of conjugate lines and mass balances, whereas it is shown that empirical correlations cannot be used for that purpose. Three different methods to extrapolate the critical point are then employed and, using the more reliable one, that point is located and added to the dataset. Further thermodynamic correlation of the data is conducted using the activity coefficient models, UNIQUAC and NRTL. While the former did not perform well, the latter was able to model the LLE and adapt to temperature changes. [ABSTRACT FROM AUTHOR]

Some key experiments are carried out to determine the solubility of N in Fe–Si liquid solutions at various compositions, temperatures, and N2 pressures using the sampling method. The Fe–Si–N system is thermodynamically modeled using the CALculation of PHAse Diagrams (CALPHAD) approach for the first time based on critical evaluation of all available experimental data. In the present thermodynamic modeling, the liquid and solid solutions of the Fe–Si–N system are described using the modified quasichemical model and compound energy formalism, respectively. In particular, the Gibbs energies of liquid, FCC_A1, and BCC_A2 solutions are carefully determined to resolve the discrepancies among existing experimental data. The solubility product of β‐Si3N4(s) in Si steels and ferrosilicon alloys, activity coefficients, and interaction parameters of N in liquid and solid Fe–Si–N solutions are determined over a wide temperature range. As an application of the database, the N solubility in Si steels and phase constitution of nitrided ferrosilicon alloys in a wide composition, temperature, and N2 pressure ranges are predicted. [ABSTRACT FROM AUTHOR]

Single-stage compression loading experiments were carried out on concrete specimens of various strengths to explore the characteristic parameters of the acoustic emission signal and its damage evolution law in the concrete damage process. These specimens were monitored in real time with acoustic emission and DIC instruments during the loading process, and internal pores and slices were scanned with CT scanning instruments after compression. The acoustic emission phenomenon was expressed using the energy activity coefficient, and the law relating to the phenomenon was summarized. The results show that when the peak and mean values in the first adjacent time domain grow rapidly, the specimen produces a large crack and enters the stage of rapid crack development, which can be taken as an indication of the impending damage to the specimen. The energy activity coefficient reflects the damage development intensity as follows: the smaller the energy activity coefficient, the more the cracks developed; the faster the speed, the larger the deformation. With an increase in the load level, the energy activity coefficient gradually tends to stabilize, and the specimen enters the stage of rapid crack development. However, when the energy activity coefficient suddenly increases again, the specimen is destabilized and destroyed. Therefore, the energy activity coefficient responds to the degree of congenital defects in the specimen. As the load increases, the energy activity coefficient is more stable, and the defects are smaller; in contrast, the energy activity coefficient drastically oscillating indicates that the material is very defective. [ABSTRACT FROM AUTHOR]

Context: 1,3-Propanediol (1,3-PDO) is a key chemical in various industries, including pharmaceuticals and material sciences, and is projected to see significant market growth. However, the current challenges in its downstream processing, particularly in terms of cost and efficiency, highlight the need for innovative solutions. Our study delves into using ionic liquids (ILs) as a potential alternative, aiming to address these critical separation challenges more sustainably and efficiently. In this study, we utilized molecular dynamics (MD) simulations and the COSMO-SAC to examine 1,3-propanediol (1,3-PDO) extraction using four imidazolium-based ionic liquids with 1-butyl-3-methylimidazolium [Bmim] cation and with different anions bis(pentafluoroethanesulfonyl)imide [NPF2]−, bis(trifluoromethylsulfonyl)imide [NTF2]−, thiocyanate [SCN]−, and trifluoromethanesulfonate [TFO]−. Molecular dynamics simulations, incorporating analysis of radial distribution functions (RDF) and spatial distribution functions (SDF), revealed that [Bmim][SCN] and [Bmim][TFO] exhibit enhanced interactions with 1,3-PDO. Notably, [Bmim][SCN] formed the most hydrogen bonds, averaging 1.639 per molecule, due to its coordinating [SCN]− anion. This was in contrast to the fewer hydrogen bonds formed by non-coordinating anions in [Bmim][NPF2] and [Bmim][NTF2]. In ternary systems, [Bmim][SCN] and [Bmim][TFO] demonstrated superior selectivity for 1,3-PDO extraction compared to the other ionic liquids, with selectivity values around 29. These findings, supported by COSMO-SAC predictive modeling, highlight the potential of [Bmim][SCN] as a promising candidate for 1,3-PDO extraction, emphasizing the importance of anion selection in optimizing ionic liquid properties for this application. Methods: In our study, we employed MD simulations, incorporating the OPLS-AA force field, and COSMO-SAC to investigate the extraction of 1,3-PDO using imidazolium-based ionic liquids: [Bmim][NTF2], [Bmim][NPF2], [Bmim][SCN], and [Bmim][TFO]. The MD simulations were conducted using LAMMPS software, focusing on elucidating the RDF, SDF, and hydrogen bonding. Analysis of the distribution coefficient (β) and selectivity (S) for the ternary mixture was also conducted. These aspects of the simulation were analyzed using TRAVIS and VMD software. Additionally, the COSMO-SAC model was employed to determine the activity coefficients of 1,3-PDO in the ionic liquids, with molecular optimization conducted using Gaussian16 and sigma profile calculations performed using COSMO-SAC. [ABSTRACT FROM AUTHOR]

The enthalpy and solubility of aqueous amino acid solutions are essential thermodynamic properties for the modeling of heat and mass balance, and these properties can be estimated by considering the activity coefficient in thermodynamic calculations. In this study, the parameters of a non‐random two‐liquid model were identified using heat capacity and solubility data together to calculate the acceptable activity coefficient for an aqueous amino acid system. As a result, a highly accurate activity coefficient model of an aqueous amino acid solution was developed, and inaccurate alternative solutions regressed with heat capacity or solubility only can be avoided. [ABSTRACT FROM AUTHOR]

The hygrometric method is used to determine new thermodynamic data on water activity and saturated aqueous solution of the water/d-sucrose/ammonium dihydrogen phosphate (ADP) system in a wide range of NH4H2PO4 molality, ranging from 0.1 to 3 mol⋅kg−1, and for various d-sucrose contents from 0 to 4 mol⋅kg−1. Powder X-ray diffraction (XRD) and attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy were used to characterize the solid state. The Pitzer–Simonson–Clegg model (PSC) is used to fit the experimental data of osmotic coefficient obtained from water activities data. The predicted saturated aqueous solutions, with the PSC model, are in good agreement with experimental data. For the concentration inferior to 1 mol⋅kg−1, the negative deviation from ideality was shown with increasing the ADP concentrations. The estimated values of the activity coefficient of d-sucrose, activity coefficient of ADP, and the Gibbs energy of transfer of ADP from water to mixture (water/d-sucrose) show that both ADP and d-sucrose exert significant salting-out effects on the aqueous solution. [ABSTRACT FROM AUTHOR]

Objective: Analysis of the evolution of methods of analysis of publication activity and citation and development of new analytical tools for their analysis: interdisciplinary coefficients, trend diagnostic chart, binary matrix clustering algorithm. Methods: The results of scientometric analysis of the occurrence of the term Activity Index using Google Books and Google Scholar, as well as SJR database were used as research materials. In addition to scientometric analysis, diagnostic and matrix analysis methods were used as research methods. Results: Based on the SJR database (1996-2019), interdisciplinarity coefficients for subject categories and subject area were constructed and calculated for the first 50 countries. The same database allowed the construction of a trend diagnostic chart in the coordinates Activity Index and Average Growth Rate for Documents in order to identify the leaders and outsiders, as well as catch-up countries and countries losing their publication potential. These charts are plotted for the top 20 countries and the top 20 subject categories. For these countries and subject categories, matrices for Activity Index (2019) and Attractivity Index (2017 - 2019) as well as binary matrices for Activity Index (50×20 dimension) before and after applying the clustering algorithm (2019) are constructed. Conclusion: The calculations performed with relative indices can be useful in planning research and scientific collaboration between countries, as they show the comparative advantages and weaknesses of country scientific systems, and also facilitate in finding partner countries for the implementation of joint scientific programs or projects that are mutually beneficial. In the future, it is advisable to build a trend diagnostic chart, when instead of calculating an increase in publication activity over the last three years, an increase in Activity Index values is considered. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the performance of the Perturbed Hard-Sphere-Chain (PHSC) equation of state (EoS) for the calculation of methane hydrate formation in the presence of ionic liquids (ILs). The van der Waals and Platteeuw model is utilized to calculate the hydrate dissociation pressure. The performance of the PHSC model is compared to cubic EoSs and the Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) model. Two activity coefficient models are used to estimate the water activity in the presence of ILs. The results show that PHSC EoS with an activity coefficient model provides lower average error values (lower than 2%) and changing the activity coefficient models does not have a great effect on reducing the error. Also, the results of cubic-based EoSs are quite remarkable considering their simplicity. The PHSC model can be utilized as a robust and efficient thermodynamic model for hydrate dissociation pressure calculation in the presence of IL. [Display omitted] • The hydrate dissociation pressure modeling in the presence of ionic liquids is studied. • The effect of the activity coefficient model on hydrate dissociation conditions is addressed. • A simple approach based on the cubic EoS shows acceptable results. • The PHSC model can be used if the minimum error is desired. [ABSTRACT FROM AUTHOR]

This work reports the ability of cosolvency and activity coefficient models in the prediction of drugs solubility in methanol + water mixtures by choosing a minimum number of experimental data point. For this purpose, the available solubility datasets of drugs were gathered from papers published from 2012 to 2022 and selected seven number of each dataset as the training data whereas the rest of datapoints were the predictive data. Moreover, the effect number of model's parameters on their accuracies was investigated by training the models with selecting of 12 data points. The results indicated that the accuracy of cosolvency models was better than the activity coefficient models; so that, the simple cosolvency model of Jouyban-Acree which does not require the physicochemical properties of drugs including melting point, fusion enthalpy and also molecular parameters of van der Waals area and volume predicted the drugs solubility with more accuracy (MRDs% of 4.1). [ABSTRACT FROM AUTHOR]

The solubility of two natural phenolic compounds (vanillic acid (VA) and vanillin (V)) in four individual solvents (ethanol, butan-2-ol, ethylene glycol, and ethyl acetate) was measured using the gravimetric method from 283.15 to 323.15 K at atmospheric pressure. The optimization of the complexes between VA--solvents and V--solvents using the B3LYP theoretic technique and the 6-31+G (d, p) basis set indicated that the absolute value of interaction energy was higher, suggesting that the interaction between solute and the solvent was stronger. In addition, two excellent activity coefficient models (NRTL and Wilson) were used to correlate and evaluate the equilibrium solubility results. The highest relative average deviation and root-mean-square deviation values for VA are 4.36% and 3.09 x 10-3, respectively, and 3.35% and 5.52 x 10-3 for V. Furthermore, the excess enthalpy of the solution was determined on the basis of thermodynamic relations and the Wilson model. The findings indicate that the dissolution process was endothermic. [ABSTRACT FROM AUTHOR]

Double-ordered manganites LnBaMn 2 O 6–δ (Ln = Nd, Sm) were shown to possess a variable oxygen content from δ = 0 to 1 while maintaining a tetragonal structure within the temperature range of 973–1223 K and under partial oxygen pressure 10−22 – 1 atm. Coulometric titration technique was successfully utilized to reveal three separated phase in these materials depending on oxygen content. Thermodynamic analysis based on experimentally obtained isothermal functions δ = f (p O 2) enabled one to develop a defect formation model suggesting a coexistence three main processes of defect formation in the studied oxides. Thus oxidation and partial disproportionation of manganese supplemented by intrinsic oxygen disordering were demonstrated to govern defect equilibrium. Different influence of activity coefficients involved in the thermodynamic model was considered. Moreover, a reduction in the radius of lanthanide was found to be favorable to expand oxygen homogeneity region and to decrease in the enthalpy of oxidation reaction. [ABSTRACT FROM AUTHOR]

Present study involves the investigation of the esterification kinetics between butyric acid and n‐butanol. This reaction was conducted in a batch reactor, utilizing homogeneous methanesulfonic acid (MSA) catalyst. Response surface methodology (RSM) was conducted prior to the kinetic study using "Design Expert; version‐11.0" for finding the causal factors influencing the conversion of butyric acid. Most important factors identified with their limits against conversions (during optimization of the process using RSM) were taken up to critically analyze the effect of them on butyric acid conversion. Concentration and activity‐based model of the process were proposed assuming second order reversible reaction scheme using homogeneous MSA catalyst. During the study of non‐ideal behavior of the system, UNIFAC model was adapted for assessing the activity coefficients of species present in equilibrated liquid phase. Experimental data were used to evaluate kinetic and thermodynamic parameters such as rate constants, activation energy, enthalpy, and entropy of the system. The endothermic nature of esterification was confirmed by positive value of enthalpy obtained. The effect of various levels of causal variables like temperature (60–90°C), catalyst concentration (0.5–1.5 wt.%), and molar ratio of n‐butanol to butyric acid (1–3) on conversion kinetics of butyric acid was investigated during transient and equilibrium phase of the reaction. It has been observed that molar ratio of butanol to butyric acid has the highest influence on the conversion. The rate equation derived offered a kinetic and thermodynamic framework to the generated data. It also exhibits a notable degree of conformity of predicted data to the experimental ones and effectively characterizes the system across different reaction temperatures, reactant molar ratio, and catalyst concentration. [ABSTRACT FROM AUTHOR]

1,1‐Diethoxybutane is a high‐potential biofuel additive that enhances various fuel properties, which include cetane number, lubricity, biodegradability, and flash point. This work presents a kinetic and thermodynamic study on the acetalization reaction between butanal and ethanol in the presence of Amberlyst‐15 wet in a batch reactor. The experiments were conducted in the temperature range 313–333 K at atmospheric pressure with three different initial molar ratios of reactants and catalyst loadings. An optimal parameter setting to achieve maximum equilibrium conversion of butanal was derived from a parametric study with these three factors. The equilibrium constant for the reaction was determined. Standard thermodynamic properties of the reaction, such as enthalpy, entropy, and Gibbs free energy, were experimentally evaluated. The activity‐based two‐parameter Langmuir‐Hinshelwood‐Hougen‐Watson rate expression was used for reaction kinetics. The activity coefficients were calculated by the UNIFAC method. The kinetic parameters and the activation energy were evaluated from the experimental data. The experimental data and data predicted by the model were found to be in good agreement. [ABSTRACT FROM AUTHOR]

Other impurity components in silicon melt at high temperature will affect P removal from metallurgical-grade silicon (MG–Si). Fe is one of the most abundant impurities in silicon and therefore probably affects P removal. In this paper, the effect of Fe on characteristics of P distribution in silicon melt during directional solidification experiments was investigated based on activity interaction coefficients of Fe to P in Si–P–Fe melt. The experimental results show that overall trend of P enrichment in experimental samples of MG–Si and Si–P alloys, but the difference in P content of each part is not significant. In the experimental samples of Si–P–Fe alloys, contents of Fe and P show a gradual increase from bottom to the top of samples. The enrichment area of P is highly overlapped with that of Fe, and P and Fe are always distributed together, confirming that Fe carries part of P along with segregation to top of sample during directional solidification process. The electron probe microanalysis results show that P forms a high enrichment within Fe distribution area in top position of sample. It is further shown that co-segregation of Fe and P occurs under the interaction force between Fe and P during directional solidification process. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) is an effective way to convert and remove hydrogen sulfide, H 2 S from natural gas streams. Amine-based ILs have recently been discovered due to their efficiency of removing H 2 S due to their excellent characteristics. However, the selection of potential amine-based ILs from a wide range combination of cations and amine-based anions are rather challenging if performed experimentally. Conductor-like Screening Model for Real Solvents (COSMO-RS) was used for the prediction of liquids thermodynamics such as activity coefficient at infinite dilution, selectivity, capacity and performance index (PI) values to evaluate the performance of each amine-based ILs and determine the most efficient ILs for H 2 S absorption without requiring any experimental data. A total of 42 previously unexplored ionic liquids, amine-based ILs from a combination of 7 amine cations and 6 anions were screened by COSMO-RS model. The findings from COSMO-RS prediction results revealed that ILs without aromatic rings displayed higher efficiencies compared to ILs with aromatic rings. Moreover, N,N,N′,N′-tetramethyl-1,3-propanediamine chloride, [TMPDA][Cl] cation-anion combinations displayed the highest PI value of 52.55 among the screened ILs thus, predicted as the most efficient ILs for H 2 S absorption. The experimental results obtained validated the COSMO-RS predictions with an approximation of ± 4.51% discrepancies between predicted and experimental data. Hence, it is concluded that COSMO-RS can be used for a reliable pre-experimental prediction and amine-based ILs approach has a huge potential for effective H 2 S absorption in industrial applications. [Display omitted] • Successfully screened an effective amine-based ILs for H 2 S absorption using COSMO-RS approach. • The synthesized ABILs possess desirable physical properties for H 2 S absorption. • The predicted results obtained were in agreement with the experimental data. • ILs of [TMPDA][Cl] displayed the highest removal efficiency for H 2 S absorption. [ABSTRACT FROM AUTHOR]

The problem of single-ion activity coefficients is addressed, primarily, in view of application of ion-selective electrodes (ISEs). A brief historical survey is followed by the consideration of the information delivered by measurements of the EMF of galvanic cells with and without liquid junction. It is shown that obtaining practically relevant data, the content of a particular ion in mixed solution requires measurements with cells with liquid junction. These measurements, in turn, require the use of individual ion activities. Several conventions aimed at accessing these values are discussed. The above-mentioned issues can be useful for teaching electrochemistry. An empirical modification of the Davies' equation is proposed: l o g γ i = - A z i 2 I 1 + a Kiell B I + D i z i I . The values of individual, ion-specific parameters a Kiell and D i have been found based on the best agreement with literature data on the mean electrolyte activity coefficients. Activity coefficients of cation, γ + , and anion, γ - , are calculated separately using the equation proposed, and the respective mean electrolyte activity coefficient is calculated according to its definition using the obtained single-ion activity coefficients: γ ± υ = γ + υ + γ - υ - . The calculated mean electrolyte activity coefficients are compared with literature data on mean electrolyte activities of 53 electrolytes (at 25 °C). The consistency of the proposed values of the individual ion parameters is achieved: for a particular ion, they remain the same in any electrolyte. For KCl and CaCl2, it is also checked whether individual ion parameter values are suitable over the temperature range from 15 to 35 °C (relevant in view of ISE application), and whether these values allow for a consistent interpretation of the ISE response in pure and mixed solutions. [ABSTRACT FROM AUTHOR]

Solubility profile for isophthalic acid (IPA) in the mixtures of propylene glycol (PG), ethylene glycol (EG) or glycerol (Gly) as co-solvents and water was determined by a shake-flask method at 293.15–313.15 K under ambient pressure (≈ 85 kPa). Considering to the presence of many factors that can be changed the experimental results, this work focused mainly on temperature, chemical structure of co-solvent and water content as the main independent variables. The measured IPA solubilities were positively enhanced with enhancing temperature in a certain co-solvent composition; however, that decreased when the water content was gradually increasing and the maximum solubility in mole fraction terms was observed in neat mono-solvents of PG (0.0084), EG (0.0053) and Gly (0.0035) at 313.15 K. It seems that the solubilization power of each co-solvent was affected by their dipole moments and especially dielectric constants; so that, PG with the lowest values of dipole moment and dielectric constant (2.27 D, 32.0) presented the highest solubilization power for IPA in compared to the EG (2.27 D, 37.0) and Gly (2.56 D, 47.0). By representation the derived equilibrium solubilities with models of Jouyban-Acree and its two versions, the modified Wilson and its combined version of van't Hoff, the mixture response surface, the combined nearly ideal binary solvent/Redlich–Kister and the Buchowski-Ksiazczak, a maximum overall average relative deviation of 9.4% was achieved. Furthermore, the thermodynamic functions of dissolution and mixing were determined from the solubility data using the modified van't Hoff equation. The results demonstrated that the dissolution process was an endothermic process and enthalpy-driven in all investigated systems. [ABSTRACT FROM AUTHOR]