Small Negative Deviations Research Articles

Radiostrontium determination by combination of automated Sr isolation and “on-column” Cherenkov detection using chromatographic model

A novel analytical solution of non-linear chromatography in case of parabolic isotherm for frontal analysis was obtained by combination of Cole-Hopf and Laplace transform. It was used for simulation of strontium capturing on chromatographic column with aim to improve quantitative determination of low-level 90Sr activities. From the experimentally determined breakthrough curves, the retention factor and the number of theoretical plates were calculated using the Glueckauf and Wenzel relations and by fitting the breakthrough curves for the linear isotherm using MatLab. These were used to simulate the breakthrough curves using a parabolic isotherm solution where the non-linear term of the isotherm was taken as a small negative deviation of the retention factor. On the base of theoretical prediction and experimental data, procedure for automated capturing of strontium on chromatographic column with specific dimension and off line „on-column“ Cherenkov detection on commercial ultra low-level liquid scintillation counter was developed. It was shown that analytical solution for parabolic isotherm in comparison with solution for linear isotherm gives better prediction of mass of captured Sr on column filled with small amount of Sr resin and SuperLig®620 in case of elevated Sr concentration, even when non-linear effect is not obvious. The solution also makes it possible to predict the mass of resin required for strontium isolation at 100% yield under given conditions. Considering the limited dimensions of the column, and consequently small mass of the resin in them, it resulted in the low efficiency of the columns, which, however, did not affect the yield in real conditions of isolation. The results have shown that the yields achieved after isolation on SuperLig®620 from real samples are 100%. In addition, it is shown that captured 90Sr can be detected through 90Y ingrowth, on column filled with strontium specific resin, with Cherenkov detection efficiency of at least 50%. The efficiency may be enhanced to 60%, depending on parameters which can affect detection efficiency change (type of column, resin type, surrounding solution, etc.). The developed procedures enable quantitative determination of 90Sr in natural water samples with MDAC below 12 mBq l−1 and solid (soil and vegetation) samples with MDAC below 6 Bq kg−1 within 2–3 days. The proposed solution may easily be implemented in radiochemical laboratories where this type of analysis is routinely done within environmental monitoring or other purposes.

Термодинамічні властивості розплавів системи Cu—In—La

Partial for the components and integral enthalpies of mixing of the ternary melts of the Cu—In—La system were determined for the first time by the method of calorimetry on five radial sections with a constant ratio of two components:, and (up to xIn = 0,02, 0,14, and 0,42, respectively) and and (up to xCu = 0,15 and 0,2, respectively) at 1220—1450 K. It is shown that when indium 1 is added to the CuxLa1-x melt, the thermal effect of its dissolution increases, which is caused by the formation of strong bonds between In and La. In the other two sections (and), the enthalpies of mixing of ternary melts decrease during dissolution. Using the reliable mixing enthalpies of the melts of the dual systems Cu—In(La) and In—La, similar parameters for liquid alloys of the Cu—In—La system were calculated according to various “geometric” and “analytical” models. It was found that the values calculated by the Redlich—Kister—Mujianu model with the triple contribution –200 agree with the determined enthalpies of mixing of melts of the Cu—In—La system within the limits of experimental errors. It was established that the minimum enthalpy of mixing of melts of the Cu—In—La system falls on the alloy of the In—La subsystem (−43,4 ± 2,1) at xLa = 0,4 at T = 1450 K, i. e., the largest contribution to the enthalpy of mixing of melts of the Cu—In—La system is made by boundary subsystem In—La. The activity of the components in the melts of this system was calculated according to the same model. It is shown that they exhibit small negative deviations from ideal solutions at 1450 K. From these data, G, S of melts of the Cu—In—La system were estimated. It was established that Gmin = –26 kJ/mol, Smin = –12 J/mol∙K, which are attributed to the In0.6La0.4 alloy. Keywords: calorimetry, copper, lanthanum, indium, thermodynamic properties, modeling, mixing enthalpies, activity of components.

Дослідження і моделювання термодинамічних властивостей розплавів систем Bi—Cu—Eu і Cu—Eu

The partial and integral enthalpies of mixing of the melts of the Bi—Cu—Eu system were determined for the first time by the method of calorimetry on three radial sections with a constant ratio of two components: xCu/xEu = 0,3/0,7, xEu/xBi = 0,23/0,77, xEu/xBi = = 0,8/0,2 at T = 1400 ± 1 K. It is shown that the partial and integral enthalpies of mixing of the studied melts are mainly exothermic. Moreover, when adding bismuth to CuхEu1-х melt, the thermal effect of dissolution of the latter increases. This is due to the formation of strong bonds between Bi and Eu. In the other two sections, the opposite happens. Using the literature enthalpies of mixing of melts of the Cu—Eu system, investigated by the method of calorimetry at 1313—1480 K in the entire range of compositions, Gibbs energies, enthalpies and entropies of the formation of melts and intermetallics, their temperature-concentration dependences, and from them — the liquidus curve of the state diagram were calculated of the studied system according to the model of the ideal associated solution. It is shown that the activities of the components in these melts exhibit small negative deviations from ideal solutions and a small amount of associates, especially Eu5Cu, is formed in them. The maximum mole fraction of the EuCu associate reaches a value of 0,09, and the other two (Eu2Cu, EuCu5) — 0,05 and 0,02. From the critically analyzed thermodynamic properties of melts of the Cu—Eu, Bi—Cu and Bi—Eu systems, their reliable data were derived, from which similar parameters for liquid alloys of the ternary system Bi—Cu—Eu were calculated according to various known models. It is shown that the experimental mixing enthalpies of melts of the Bi—Cu—Eu system best agree with those calculated according to the Redlich—Kister—Mujianu model. It was established that ΔHmin = = −61,5 kJ/mol at xBi = 0,5. According to the same model, G, S of these melts were calculated. It was established that Gmin = –40 kJ/mol, and Smin = –18 J/mol•K, the minima of which also fall on the boundary subsystem Bi—Eu, i.e., the main contribution to the interaction energy between different-named atoms of melts of the Bi—Cu—Eu system contribute to the components of this subsystem. Keywords: calorimetry, melts, intermetallics, thermodynamic properties, systems, Bi—Cu—Eu, Cu—Eu, ideal associated solution model, phase equilibria.

Термодинамічні властивості розплавів систем Cu—Yb і Cu—In—Yb

The partial and integral enthalpies of mixing of the melts the Cu-Yb system in the composition range 0 < xCu <0,7 and for 5 sections of Cu – In – Yb system with a constant ratio of the other two components (xCu/xIn=0,36/0,64; xCu/xIn= 0,62/0,38; xIn/xYb= 0,62/0,38; xCu/xYb =0,64/0,36; xCu/xYb =0,21/0,79) to x3 = 0.3 by method isoperibolical calorimetry in the temperature range 1453-1473K first were determined. Using the model of ideal associated solutions (IAR), all the thermodynamic properties (Gibbs energies of mixing melts, enthalpy and entropy of formation of intermetallic compounds and associates) of the Cu–Yb system were calculated. It turned out that the activity of the components in the melts of this system exhibit small negative deviations from ideal solutions. Calculations using the IAR model also made it possible to establish that with increasing temperature it increases slightly, but more significantly. Also were obtained the coordinates of the liquidus curve of the diagram state of the studied system. The principal contribution to the enthalpies of mixing in the liquid alloysof the Cu–In–Yb system gives the border subsystem In–Yb. Because the minimum of the mixing enthalpies in the ternary sysytem Cu–In–Yb shifts towards the equiatomic alloy concentration of subsystem In–Yb (-36,5±1,0) at Т= 1453 К. Using the experimental partial and integral enthalpies of mixing, the activities of the components in the melts of binary limiteyted system of melts of the Cu–In–Yb ternary system, calculated according to «geometric» and the Redlich-Kister-Mujian models in a wide range of concentrations. It is established that the experimental ∆H, and calculated analogical datas according to the Redlich-Kister-Mujianu model agree between. It is shown that the activities of the components in the melts of this system, calculated according to the Redlich-Kister model, show small negative deviations from ideal solutions at 1453 K. From these of data calculated G, S. It was found that Gmin = –19 kJ/mol, Smin = –15 J/mol*K for the alloy In0,5Yb0,5. This correlates with the determined thermochemical properties of the melts Cu –In– Yb system. Keywords: calorimetry, the melts, intermetallic, thermodynamic properties, Cu, Yb, In, the model of ideal associated solutions, the Redlich—Kister—Mujianu model, phase equilibria.

Explorations into the mean nearest-neighbor distance in uniform and unimodal random distributions

The two-dimensional mean nearest neighbor distance and other distance distribution metrics, in uniform and unimodal normal distributions of random sequential addition hard disc computer-generated patterns, have been studied. First, more instances have been recorded in sufficient number to provide for more averaging and higher resolution data. Second, a facile, surprisingly accurate, method for estimating mean nearest neighbor distance in 2D uniform random distributions is presented. Third, the change in mean nearest neighbor distance as a function of the area fraction and standard deviation of the normal distribution of the disc diameter is discussed. It has been found that, while the changes are small (on the order of a few percent) both positive and negative deviations are observed. Consequences for higher dimension problems and multi-modal distributions are discussed.

Eutectic Mixtures Based on Polyalcohols as Sustainable Solvents: Screening and Characterization

Despite some promising potential applications of eutectic systems containing choline chloride ([Ch]Cl) and a polyalcohol, a detailed investigation of the thermodynamic behavior of these systems is still missing. In this work, the solid–liquid equilibria phase diagrams of binary systems containing [Ch]Cl and one from six different polyalcohols (ethylene glycol (EG), 1,3-propanediol, glycerol (Gly), meso-erythritol, xylitol, and sorbitol) were measured in the full composition. Except for the mixtures with Gly or EG, a quasi-ideal behavior in the [Ch]Cl solubility curve is observed. In the polyalcohol solubility curve, the mixtures present small negative deviations from ideality, except for [Ch]Cl + EG, which is slightly positive. The solid–liquid phase diagrams show a large liquid composition window, and not a fixed stoichiometry for the eutectic points, where the mixtures can be used as solvents close to, or below, room temperature. Aiming at their application, viscosities and densities were measured at the eutectic point in the temperature range from 278.15 to 373.15 K. All systems present densities and viscosities higher than water, which is directly related to the strong interactions between the components. Solvatochromic parameters were measured to characterize the solvents, and they show that solvent tunability can be achieved by varying the polyalcohol mole fraction.

Effects of global warming and solar geoengineering on precipitation seasonality

The effects of global warming and geoengineering on annual precipitation and its seasonality over different parts of the world are examined using the piControl, 4xCO2 and G1 simulations from eight global climate models participating in the Geoengineering Model Intercomparison Project. Specifically, we have used relative entropy, seasonality index, duration of the peak rainy season and timing of the peak rainy season to investigate changes in precipitation characteristics under 4xCO2 and G1 scenarios with reference to the piControl. In a 4xCO2 world, precipitation is projected to increase over many parts of the globe, along with an increase in both the relative entropy and seasonality index. Further, in a 4xCO2 world the increase in peak precipitation duration is found to be highest over the subpolar climatic region. However, over the tropical rain belt, the duration of the peak precipitation period is projected to decrease. Furthermore, there is a significant shift in the timing of the peak precipitation period by 15 days–2 months (forward) over many parts of the Northern Hemisphere except for over a few regions, such as North America and parts of Mediterranean countries, where a shift in the precipitation peak by 1–3 months (backward) is observed. However, solar geoengineering is found to significantly compensate many of the changes projected in a 4xCO2 scenario. Solar geoengineering nullifies the precipitation increase to a large extent. Relative entropy and the seasonality index are almost restored back to that in the control simulations, although with small positive and negative deviations over different parts of the globe, thus, significantly nullifying the impact of 4xCO2. However, over some regions, such as northern parts of South America, the Arabian Sea and Southern Africa, geoengineering does not significantly nullify changes in the seasonality index seen in 4xCO2. Finally, solar geoengineering significantly compensates the changes in timing of the peak and duration of the peak precipitation seen in 4xCO2.

Manipulation of profits in Italian publicly-funded healthcare trusts

ABSTRACTThis paper examines earnings management in state-funded Italian healthcare trusts. Italy is unique in requiring trusts to have balanced budgets by law. Small negative and positive deviations from a balanced budget had quite different consequences. The authors found no evidence of accounting manipulation when trusts posted small losses. However, trusts were found to manipulate discretionary accruals, provisions and non-operating expenses to reduce small positive deviations from zero-profit.

Density, Surface Tension, and Viscosity of Liquid Pb–Sb Alloys

With the use of the discharge crucible method, the density, surface tension, and viscosity of Pb–Sb liquid alloys were determined. The experiments were performed in the temperature range between 573 and 1050 K. The measurements were conducted in a glovebox filled with high-purity argon, which was continuously circulated between the glovebox and the purification system. The measurements were conducted for four alloys of the composition 16.75, 40, 60, and 90 atom % Sb. The experimental data on the surface tension and viscosity were compared to those from modeling. The new experimental data and the corresponding model-predicted values exhibit good agreement, and only small differences in linear changes between the surface tensions of Pb and Sb can be observed. This can be attributed to small negative deviations of the thermodynamic properties from Raoult’s law and a relatively small difference between the surface tensions of the pure components. In the case of viscosity, the measured data were in excellent a...

Do small samples underestimate mean abundance? It depends on what type of bias we consider.

Former authors claimed that, due to parasites' aggregated distribution, small samples underestimate the true population mean abundance. Here we show that this claim is false or true, depending on what is meant by 'underestimate' or, mathematically speaking, how we define 'bias'. The 'how often' and 'on average' views lead to different conclusions because sample mean abundance itself exhibits an aggregated distribution: most often it falls slightly below the true population mean, while sometimes greatly exceeds it. Since the several small negative deviations are compensated by a few greater positive ones, the average of sample means approximates the true population mean.

Solvation of LiCl in model liquids with high to low hydrogen bond strengths

We performed molecular dynamics simulations in order to understand the effect of increasing or decreasing the hydrogen bond strengths on the structure, entropy, and mobility of modified hybrid water models as pure solvents and solutions using LiCl as the solute of constant mole fraction of 0.025. The hybrid potential parameter (λ) is used to enhance or diminish the Lennard-Jones (LJ) dispersion-repulsion contribution relative to the electrostatic contribution, which in turn changes the hydrogen bond strength of water. The local structure around water molecules and ions was quantified using radial and angular distribution functions, triplet correlation functions, and tetrahedral order parameter. The structure of the liquid undergoes a change from tetrahedral water-like to LJ-like with decreasing hydrogen bond strength or increasing λ for both pure solvents and solutions. The number of ion-pairs monotonically increases with decreasing hydrogen bond strength. Large ion-clusters regardless of charge are formed in liquids with LJ-like characteristics. The local tetrahedral structure of Li+ depends on the hydrogen bond strength of water and the tetrahedral angle gradually shifts to lower (60°) and higher (180°) angle preferences with decreasing hydrogen bond strength. The first peak height of gOO(r), pair entropy, diffusivity, viscosity, and ionic conductivity varies non-monotonically as a function of λ due to the incompatibility of two extreme types of structure at very low and high λ values. The validity of the Stokes-Einstein and Nernst-Einstein relations are also examined. At very high and low hydrogen bond strengths or very low and high λs, respectively, the Nernst-Einstein deviation parameter shows small negative deviation.

Therapeutic Drug Monitoring of Everolimus: Comparability of Concentrations Determined by 2 Immunoassays and a Liquid Chromatography Tandem Mass Spectrometry Method.

Therapeutic drug monitoring is recommended to guide therapy with the immunosuppressant everolimus (EVL) in solid organ transplantation to prevent rejections and to limit toxicity. For therapeutic drug monitoring, predose EVL concentrations are measured in whole blood mainly by liquid chromatography tandem mass spectrometry (LC-MS/MS). In addition, 2 immunoassays [Quantitative Microsphere System (QMS) EVL and Elecsys EVL] are commercially available. The aim of this study was to evaluate the comparability of EVL results determined with the 2 immunoassays and a validated LC-MS/MS test using samples from kidney, liver, and heart transplant (KT, LT, and HT, respectively) recipients. Analysis of predose samples from KT (n = 56), LT (n = 60), and HT (n = 59) recipients, obtained at variable time points after transplantation, was performed by LC-MS/MS and with the 2 immunoassays. The QMS EVL assay was applied on Dimension Xpand Plus and the Elecsys EVL assay on cobas e 411 analyzer. Results were compared by the Spearman's rank correlation coefficient, unbiased Passing and Bablok linear regression test, and Bland-Altman plot. Results generated with both immunoassays correlated well with those of LC-MS/MS. An overestimation of EVL concentrations by the Elecsys EVL compared with LC-MS/MS was observed (mean bias: 34.2%). Using the QMS EVL, a small but significant negative deviation (mean bias: -8.0%) was found. Looking at KT, HT, and LT samples separately, the bias to LC-MS/MS seen with the Elecsys EVL was similar. With the QMS EVL, the best agreement was observed with the KT samples followed by LT and HT. Results generated by the 3 methods are not consistent regarding their diagnostic value. Both laboratories and manufacturers should take care to inform their costumers about the between-method differences to avoid misinterpretation of the results in clinical practice.

Determination of the Exact Particle Radius Distribution for Silica Nanoparticles via Capillary Electrophoresis and Modeling the Electrophoretic Mobility with a Modified Analytic Approximation.

In this study, we use aqueous dispersions of amorphous silica nanoparticles of various sizes to investigate whether electropherograms recorded from capillary electrophoresis experiments can be converted directly into exact number-based particle radius distributions, provided that there is a relaxation effect-based size selectivity of the electrophoretic mobility and provided that the electrokinetic potential ζ of the particles can be regarded to be homogeneous over the surface of the particles, independent of the particle size. The results of this conversion procedure are compared with number-based particle radius distributions obtained from a large set of transmission electron microscopy (TEM) data. For this specific example, it is shown that the modified analytic approximation developed by Ohshima adequately describes the mobility-dependent relaxation effect and the electrophoretic mobility of the particle as a function of the reduced hydrodynamic radius and electrokinetic potential, which is a prerequisite for the presented procedure. Simultaneously, we confirmed that for the given Debye length/particle diameter ratio the electrokinetic surface charge density can be regarded to be size-invariant (including spherical geometry and planar limiting case). It is shown that the accuracy of the results of the developed method is comparable to that gained by a large set of TEM data, which is important when a precise description of the particle size distribution is needed to deduce conclusions regarding the underlying mechanism(s) of particle growth. The values obtained for the dispersion (width) of the distribution show only a small negative deviation, when compared with the TEM data (4-16%).

Theoretical assessment on mixing properties of liquid Tl–Na alloys

Thermodynamic and structural properties of mixing of molten Tl–Na alloys at 673 K have been investigated using quasi-chemical model. To understand the mixing behaviour in more detail, emphasis is placed on the role of interaction energy term, and viscosity and surface tension of the alloys have also been analysed under statistical considerations. Our study shows negative deviation from the Raoultian behaviour in the properties of Tl–Na alloy thereby indicating hetero-coordination in the Tl–Na melt at 673 K in the full range of concentration. Theoretically, computed thermodynamic data at 673 K agree very well with the corresponding experimental data. The viscosities of the alloys computed from Kaptay equation show small negative deviation and those computed from Singh and Sommer’s formulation show small positive deviation from ideal values while the Budai-Benko-Kaptay equation predicts noticeable negative deviation in Na-rich end and positive deviation in Tl-rich end of the composition. The calculations of surface tension reveal that results obtained from layered structure approach and compound formation model are in good agreement in the Na-rich side and in reasonable agreement in Tl-rich side of the composition, while those computed from Butler equation show noticeable deviations in the intermediate compositions. Both the viscosity and surface tension of liquid Tl–Na alloys increase with addition of Tl-component, viscosity having approximately linear variation with concentration. The study shows that there is non-linear variation in surface composition with bulk concentration and for most of the compositions the surface of the alloy is enriched with Na-atoms which segregate to the surface.

Simulation of the local structure, mixing properties, and stability of Ca x Sr1 − x CO3 solid solutions by the interatomic potential method

Strontianite (SrCO3)-aragonite (CaCO3) solid solutions have been simulated by the interatomic potential method. The composition dependences of the unit cell parameters, the unit cell volume, and bulk modulus have been constructed. It has been shown that the volume of the unit cell and bulk modulus show small negative deviations from additivity. The local structure of solid solutions has been analyzed. It has been established that the enthalpy of mixing is positive and, for the equimolar composition, reaches a maximum of 2.45 kJ/mol. Based on the composition dependences of the Gibbs free energy for the temperature range of 300–650 K, the solvus of the system has been constructed. According to the obtained data, the solubility of aragonite in strontianite under ambient conditions is 5.5 mol %, while that of strontianite in aragonite is 2.8 mol %. The miscibility gap of the system disappears at around 450 K. The calculated results have been compared with the experimental data.

Synthesis of low molecular weight poly(vinyl acetate) and its application as plasticizer

ABSTRACTPoly(vinyl acetate), PVAc, with a degree of polymerization Xn = 10 was prepared by chain‐transfer radical polymerization using carbon tetrachloride and used as oligomeric plasticizer for commercial PVAc. However, the chlorinated chain ends cause a low thermal stability requiring mild Cl/H substitution. The product exhibits high thermal stability and excellent melt‐compounding properties. Blends of oligomeric and commercial PVAc show single glass transition temperatures which decrease with higher oligomer content and exhibit small negative deviations from Fox' linear additivity rule. This indicates plasticization and miscibility being mainly due to entropic effects. Injection‐moulded thick specimens show ductile behaviour at oligomer contents >10 wt %, while sheets with a thickness of 0.2–0.5 mm appear flexible already at 7.5 wt %. The oxygen permeability coefficients are an order of magnitude lower than those of low‐density polyethylene. Due to the sum of their properties, the plasticized sheets present a promising alternative in the preparation of barrier materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40226.

Existence of minimum molar volumes (maximum packing densities) in morphotropic series of mixed oxides and fluorides

Plots of the cubic root of the formula volume, (V/Z)1/3, vs. cation radius have been built for several morphotropic series of mixed oxides and fluorides. These plots are linear for isostructural compounds but exhibit discontinuities at morphotropic transitions. The classical homology rule ‘larger cation – higher its coordination number (CN) – denser the structure’ is only valid (with few exceptions) for substitutions of relatively small cations. Substitutions of large cations usually lead to opposite volume changes, regardless of increase or decrease in CNs. As a result, the densest structure types often appear with ions of somewhat intermediate size in a series. The discovery of the post-perovskite silicate phase, which greatly influenced mineralogy and geophysics, could be predicted four decades earlier, if proper attention had been paid to the small negative deviation of the layered CaIrO3 from the plot for CaMO3 perovskites. An analysis of the volume relations reveals some errors and leads to several predictions.

(Vapour + liquid) equilibria, volumetric and compressibility behaviour of binary and ternary aqueous solutions of 1-hexyl-3-methylimidazolium chloride, methyl potassium malonate, and ethyl potassium malonate

(Vapour + liquid) equilibrium data (water activity, vapour pressure, osmotic coefficient, and activity coefficient) of binary aqueous solutions of 1-hexyl-3-methylimidazolium chloride ([C 6mim][Cl]), methyl potassium malonate, and ethyl potassium malonate and ternary {[C 6mim][Cl] + methyl potassium malonate} and {[C 6mim][Cl] + ethyl potassium malonate} aqueous solutions were obtained through the isopiestic method at T = 298.15 K. These results reveal that the ionic liquid behaves as surfactant-like and aggregates in aqueous solutions at molality about 0.4 mol · kg −1. The constant water activity lines of all the ternary systems investigated show small negative deviations from the linear isopiestic relation (Zdanovskii–Stokes–Robinson rule) derived using the semi-ideal hydration model. The density and speed of sound measurements were carried out on solutions of methyl potassium malonate and ethyl potassium malonate in water and of [C 6mim][Cl] in aqueous solutions of 0.25 mol · kg −1 methyl potassium malonate and ethyl potassium malonate at T = (288.15 to 308.15) K at atmospheric pressure. From the experimental density and speed of sound data, the values of the apparent molar volume, apparent molar isentropic compressibility and excess molar volume were evaluated and from which the infinite dilution apparent molar volume and infinite dilution apparent molar isentropic compressibility were calculated at each temperature. Although, there are no clear differences between the values of the apparent molar volume of [C 6mim][Cl] in pure water and in methyl potassium malonate or ethyl potassium malonate aqueous solutions, however, the results show a positive transfer isentropic compressibility of [C 6mim][Cl] from pure water to the methyl potassium malonate or ethyl potassium malonate aqueous solutions. The results have been interpreted in terms of the solute–water and solute–solute interactions.

Thermodynamic characteristics of the Pb-Bi alloys in the KCl-PbCl2 melt

The thermodynamic properties of the Pb-Bi alloys containing from 1.5 to 95 mol % Pb are investigated in a molten mixture of potassium and lead chlorides in a temperature range of 723–873 K by measuring the equilibrium values of the electromotive force. The partial and integral thermodynamic characteristics of the system are calculated, and its small negative deviations from ideality are established.

Volumetric Properties for Binary Mixtures of Nonane + Decane at Temperatures from T=283.15 to 353.15 K and at p=0.7 atm

Densities of the binary mixture of nonane with decane were measured at temperatures from 283.15 to 353.15 K at atmospheric pressure (0.7 atm). Measurements have been made over the full range of compositions and for the pure compounds by using a vibrating-tube densimeter (VTD). Excess molar volumes have been obtained from these experimental results and were fitted to a Redlich–Kister type expansion. The excess molar volumes exhibit small positive and small negative deviations from ideal behavior in the temperature interval studied. Partial molar volumes and partial molar volumes at infinite dilution have been determined for each component.