[en] Deep eutectic solvents (DESs), widely used in industrial and pharmaceutical applications, still lack a complete understanding of their physicochemical properties from a microscopic perspective. The control and efficiency of applications utilizing DESs hinge significantly on their transport properties. In this article, we report our simulation and theoretical studies on DESs unravelling the microscopic diffusion mechanisms which provide an insight into the emergence of their macroscopic transport properties. We investigate how the properties of DESs depend on their components and composition, with a focus on the pivotal role played by molecular interactions. Additionally, we explore the modulation of these interactions by water to analyze the correlation between water concentration and molecular diffusion rate in these systems. Our findings suggest that a thorough understanding of complex formation and kinetics in DESs can provide the necessary link to interpret the emergence bulk transport properties from molecular diffusion. (author)

[en] Experiments have widely shown that a steady-state lamellar eutectic solidification front is destabilized on a scale much larger than the lamellar spacing by the rejection of a dilute ternary impurity and forms two-phase cells commonly referred to as ''eutectic colonies.'' We extend the stability analysis of Datye and Langer [V. Datye and J. S. Langer, Phys. Rev. B 24, 4155 (1981)] for a binary eutectic to include the effect of a ternary impurity. We find that the expressions for the critical onset velocity and morphological instability wavelength are analogous to those for the classic Mullins-Sekerka instability of a monophase planar interface, albeit with an effective surface tension that depends on the geometry of the lamellar interface and, nontrivially, on interlamellar diffusion. A qualitatively new aspect of this instability is the occurrence of oscillatory modes due to the interplay between the destabilizing effect of the ternary impurity and the dynamical feedback of the local change in lamellar spacing on the front motion. In a transient regime, these modes lead to the formation of large scale oscillatory microstructures for which there is recent experimental evidence in a transparent organic system. Moreover, it is shown that the eutectic front dynamics on a scale larger than the lamellar spacing can be formulated as an effective monophase interface free boundary problem with a modified Gibbs-Thomson condition that is coupled to a slow evolution equation for the lamellar spacing. This formulation provides additional physical insights into the nature of the instability and a simple means to calculate an approximate stability spectrum. Finally, we investigate the influence of the ternary impurity on a short wavelength oscillatory instability that is already present at off-eutectic compositions in binary eutectics. (c) 1999 The American Physical Society

No abstract available

[en] The Co–C eutectic fixed point has been popular for thermocouple calibration since 2010. In this study, the ITS-90 temperature of a Co–C eutectic fixed-point cell intended for thermocouple calibration of noble thermocouples was measured using a radiation thermometer and a group of Pt/Pd and PtRh10%-Pt thermocouples. Satisfactory consistency was observed for measurements using both methods. (paper)

[en] A mistake in the eutectic growth model published by Adrian V. Catalina et al. (Adrian V. Catalina, Subhayu Sen, and Doru M. Stefanescu: Metall. Mater. Trans. A, 2003, vol. 34A, pp. 383–94) was identified. First, we have re-derived the model following Catalina’s assumption. Furthermore, the two Fourier coefficients were directly obtained following the classical eutectic model (JH model). Finally, the validity of our derivation is closed-loop verified based on the combination of the above two derivations.

No abstract available

[en] By performing first principles calculations, we investigate the status and migration behavior of oxygen in liquid lead–bismuth eutectic (LBE). We find that oxygen prefers to bond with four Pb atoms, forming a tetrahedron-like oxide complex in LBE. Driven by temperature effect, each oxide complex diffuses, with undergoing a dynamical exchange between one of its first-neighboring Pb atoms and a second-neighboring metallic atom. In addition, the diffusion coefficient of oxygen in LBE is calculated at 500, 800 and 1000 K, respectively

[en] Short communication

[en] Understanding the speciation and kinetics of metal ions in heterogeneous hydrogen bonded deep eutectic solvents (DES) has immense importance for their wide range of applications in green technology, environmental remediation and nuclear industry. Unfortunately, the fundamental nature of the interaction between DES and actinide ions is almost completely unknown. In the present work, electrochemical investigations of uranyl ion (UO₂²⁺) in DES (Reline) consisting of choline chloride (ChCl) as hydrogen-bond acceptor and urea as the hydrogen-bond donor, has been initiated

[en] Secondary dendrite arm coarsening model developed by Feurer and Wunderlin was used in this study. The parameters of the model were adjusted by following a simple approach to find an equivalent eutectic composition based on the alloying additions. Results showed the simple model proposed in this study provided good fits to data from literature on the 319 alloy as well as Al-Si-Cu alloys with various compositions.