This work presents an assessment of solubility data for rare earth metal sulfates: generally of trivalent metals, some of divalent metals, and of tetravalent Ce in water and in aqueous multicomponent systems. Compilations of all available experimental data are introduced for each rare earth metal sulfate with a corresponding critical evaluation. Every such evaluation contains a collection of all solubility results in water, a selection of suggested solubility data, and a brief discussion of the multicomponent systems. Because the multicomponent systems were seldom studied more than once, no systematic evaluations of such data were made. This is the first part of the volume, related to Sc, Y, and La sulfates. The corresponding literature has been covered through the end of 2025.
This paper reports a critical evaluation of high-temperature boron thermodynamic data, with a focus on pressurized water reactor (PWR) applications. The thermodynamics for aqueous borate and polyborate species implemented in most computer codes have been largely based on potentiometric data measured between 50 and 200 °C at Oak Ridge National Laboratory in the early 1970s. Recently, the dataset has been extended down to 10 °C and up to 350 °C as part of an EPRI-funded comprehensive experimental study by the University of Guelph (2016–2023). This paper reports a critical review and evaluation of high-temperature thermodynamic data for polyborate speciation, boric acid species volatility, and metal alkali borates solubility to provide the basis of a revised thermodynamic model for boric acid chemistry in high-temperature water. The revised model improves the ability to simulate the chemistry that takes place in PWR primary systems.
This study systematically investigates the pressure dependence of the melting points of three gallium-based eutectic alloys-Ga-In, Ga-Sn, and Ga-Zn-as potential secondary temperature standards. Open-type fixed-point cells were used in conjunction with a precision temperature-pressure control system, and five independent realization cycles were performed for each alloy to ensure high reproducibility. The system exhibits exceptional stability, maintaining melting plateaus for similar to 100 h with a drift of less than 0.5 mK over 25 h. The experimental results demonstrate a strictly linear negative correlation between melting temperature and applied pressure for all three alloys. The measured pressure coefficients dT/dp are -0.93 & times; 10(-8) K Pa-1 for Ga-In, -1.15 & times; 10(-8) K Pa-1 for Ga-Sn, and -1.38 & times; 10(-8) K Pa-1 for Ga-Zn. The experimental standard deviations of the means for these three coefficients are all below 0.05 & times; 10(-8) K Pa-1, confirming the high precision and statistical reliability of the determined values. These coefficients are in excellent agreement with thermodynamic (CALPHAD) calculations (deviations below 10%). Characteristic melting temperatures were determined using the tangent intersection method: 15.647 72 degrees C for Ga-In and 25.199 99 degrees C for Ga-Zn (the melting temperature of Ga-Sn is 20.481 79 degrees C), with combined expanded uncertainties (k = 2) of 0.37 and 0.49 mK, respectively. This work establishes a robust theoretical and experimental foundation for understanding pressure-induced phase behavior in multi-component liquid metals, providing critical thermodynamic insights for deploying Ga-based phase-change materials as highly stable thermal references in extreme or non-standard engineering environments.
Surface tension values for 94 liquids whose molecules include cyclic structures have been compiled from databases, books, and papers in the literature for different temperatures. These values were screened, and for each fluid the number of selected data ranges from 9 to 195, yielding a total of 2389 data points, of which 560 correspond to experimental ones. Recommended temperature-dependent correlations are proposed for 92 of the 94 substances considered, as the selected datasets for the remaining two exhibit significant discrepancies. The Guggenheim-Katayama analytical expression was applied using two or four adjustable coefficients, except for methylcyclopropane, for which six were required. The proposed correlations yield mean absolute deviations below 0.4 mN/m and mean absolute percentage deviations below 1.7%, except for 4-methylcyclopentene and 1-ethyltetralin, for which values around 2.3% were obtained. Moreover, percentage deviations below 9.1% are found for almost all selected data, with the only exceptions being two values for cyclopentane and one for 1-ethyltetralin, for which two different data sources provide different values at the highest temperatures. In general, the largest deviations are due to this kind of disagreement rather than to poor fitting by the correlation model. These new correlations expand the existing collection, which includes common substances, alcohols, refrigerants, organic acids, n-alkanes, esters, ethers, and alkenes, by incorporating 25 alkylcyclohexanes, 15 alkylcyclopentanes, 14 cycloaliphatic alcohols, 7 cycloalkanes, 13 cycloalkenes, 12 cyclobenzenes, and 6 multiring cycloalkanes, classified according to DIPPR nomenclature.
We provide recommended values for the second virial coefficient, $B(T)$, and its uncertainty, for molecular nitrogen and oxygen. The temperature range covered is $20-3000$ K for nitrogen and $20-2000$ K for oxygen. The recommendations are based on tuning previously published state-of-the-art ab initio pair potentials so that the $B(T)$ calculated from the potentials match selected high-accuracy experimental data; for nitrogen the tuning utilizes values of $B$ derived from literature density data with greatly reduced uncertainty by analyzing the data with the aid of ab initio calculated higher virial coefficients. Quantum effects on $B$ are fully included with the path-integral Monte Carlo method. The resulting $B(T)$ have uncertainties similar to those of the best experimental data, but cover a much wider temperature range.
