Activity coefficients of binary methanol alcohol mixtures from cluster weighting

The hydrogen bond network of different small alcohols is investigated via cluster analysis. Methanol/alcohol mixtures are studied with increasing chain length and branching of the molecule. Those changes can play an important role in different fields, including solvent and metal extraction. The extended tight binding method GFN2-xTB allows the evaluation and geometry optimization of thousands of clusters built via a genetic algorithm. Interaction energies and geometries are evaluated and discussed for the neat systems. Thermodynamic properties, such as vaporization enthalpies and activity coefficients, are calculated with the binary quantum cluster equilibrium (bQCE) approach using our in-house code Peacemaker 2.8. Combined distribution functions of the distances against the angles of the hydrogen bonds are evaluated for neat and mixed clusters and weighted by the equilibrium populations achieved from bQCE calculations

Investigation of a standardized qualitative behaviour assessment and exploration of potential influencing factors on the emotional state of dairy calves

open4siopenMarta Brscic , Nina Dam Otten , Barbara Contiero , Marlene Katharina KirchnerBrscic, Marta; Dam Otten, Nina; Contiero, Barbara; Katharina Kirchner, Marlen

Water in Protic Ionic Liquid Electrolytes: From Solvent Separated Ion Pairs to Water Clusters

Abstract The large electrochemical and cycling stability of “water‐in‐salt” systems have rendered promising prospective electrolytes for batteries. The impact of addition of water on the properties of ionic liquids has already been addressed in several publications. In this contribution, we focus on the changes in the state of water. Therefore, we investigated the protic ionic liquid N ‐butyl‐pyrrolidinium bis(trifluoromethanesulfonyl)imide with varying water content at different temperatures with the aid of molecular dynamics simulations. It is revealed that at very low concentrations, the water is well dispersed and best characterized as shared solvent molecules. At higher concentrations, the water forms larger aggregates and is increasingly approaching a bulk‐like state. While the librational and rotational dynamics of the water molecules become faster with increasing concentration, the translational dynamics are found to become slower. Further, all dynamics are found to be faster if the temperature increases. The trends of these findings are well in line with the experimental measured conductivities.From single molecules to bulk liquid : The state of water in a protic ionic liquid at different concentration is investigated by the aid of molecular dynamics simulations. At a low concentration, the water shows the behavior of free molecules. With increasing concentration, the formation of clusters can be observed. Finally, at concentrations near the phase separation the behavior approaches that of the bulk liquid. imag

Influence of Complexing Additives on the Reversible Deposition/Dissolution of Magnesium in an Ionic Liquid

Aiming at a fundamental understanding of the synergistic effects of different additives on the electrochemical Mg deposition/dissolution in an ionic liquid, we have systematically investigated these processes in a combined electrochemical and theoretical study, using 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMP‐TFSI) as the solvent and a cyclic ether (18‐crown‐6) and magnesium borohydride as additives. Both crown ether and BH4− improve Mg deposition, its reversibility, and cycling stability. The combined presence of both additives and their concentration relative to that of Mg$^{2+}$ are decisive for more facile and reversible Mg deposition/dissolution. These results and those of quantum chemical calculations indicate that 18‐crown‐6 can partly displace TFSI− from its direct coordination to Mg$^{2+}$. Furthermore, the interaction between Mg$^{2+}$ and directly coordinated TFSI− is weakened by coordination with 18‐crown‐6, preventing its Mg$^{+}$‐induced decomposition. Finally, Mg deposition is improved by the weaker overall coordination upon Mg$^{2+}$ reduction to Mg$^{+}$

ICON in Climate Limited-area Mode (ICON release version 2.6.1): a new regional climate model

For the first time, the Limited-Area Mode of the new ICON (Icosahedral Nonhydrostatic) weather and climate model has been used for a continuous long-term regional climate simulation over Europe. Built upon the Limited-Area Mode of ICON (ICON-LAM), ICON-CLM (ICON in Climate Limited-area Mode, hereafter ICON-CLM, available in ICON release version 2.6.1) is an adaptation for climate applications. A first version of ICON-CLM is now available and has already been integrated into a starter package (ICON-CLM_SP_betal). The starter package provides users with a technical infrastructure that facilitates long-term simulations as well as model evaluation and test routines. ICON-CLM and ICON-CLM_SP were successfully installed and tested on two different computing systems. Tests with different domain decompositions showed bit-identical results, and no systematic outstanding differences were found in the results with different model time steps. ICON-CLM was also able to reproduce the large-scale atmospheric information from the global driving model. Comparison was done between ICON-CLM and the COnsortium for Small-scale MOdeling (COSMO)-CLM (the recommended model configuration by the CLM-Community) performance. For that, an evaluation run of ICON-CLM with ERA-Interim boundary conditions was carried out with the setup similar to the COSMO-CLM recommended optimal setup. ICON-CLM results showed biases in the same range as those of COSMO-CLM for all evaluated surface variables. While this COSMO-CLM simulation was carried out with the latest model version which has been developed and was carefully tuned for climate simulations on the European domain, ICON-CLM was not tuned yet. Nevertheless, ICON-CLM showed a better performance for air temperature and its daily extremes, and slightly better performance for total cloud cover. For precipitation and mean sea level pressure, COSMO-CLM was closer to observations than ICON-CLM. However, as ICON-CLM is still in the early stage of development, there is still much room for improvement

Physical activity, leisure and evaluation of health in the perspective of users in hemodialysis

Objective: to characterize chronic renal users who do hemodialysis in a Nephrologic Unit in a city in the northwestern region of Rio Grande do Sul and to relate physical and leisure activities according to perceptions regarding the evaluation of their health in general. Method: quantitative, analytical, descriptive, cross-sectional research with 77 renal chronic users in hemodialysis program. Data was collected from April to July/2010, after approval of the Ethics Committee, Opinion 02780243000-09. Instruments: sociodemographic, physical activity, leisure, health assessment - KDQOL-SFTM. Data analysis using descriptive statistics. Results: the majority are men, married, 45,5% elderly, low education, 64,9% practicing physical activity, 61% of leisure, 37,7% need help with everyday activities. At the intersection of the variables "leisure" and "health assessment", out of 61,0% that realize it, 33,8% rated health as "good" and 24,7% as "regular". Conclusion: the performance of physical activity and/or leisure contributes to quality of life, allowance for qualification of care, prevention and health promotion

On the rich chemistry of pseudo‐protic ionic liquid electrolytes

Mixing weak acids and bases can produce highly complicated binary mixtures, called pseudo-protic ionic liquids, in which a complex network of effects determines the physicochemical properties that are currently impossible to predict. In this joint computational-experimental study, we investigated 1-methylimidazole-acetic acid mixtures through the whole concentration range. Effects of the varying ionization and excess of either components on the properties, such as density, diffusion coefficients, and overall hydrogen bonding structure were uncovered. A special emphasis was put on understanding the multiple factors that govern the conductivity of the system. In the presence of an excess of acetic acid, the 1-methylimidazolium acetate ion pairs dissociate more efficiently, resulting in a higher concentration of independently moving, conducting ions. However, the conductivity measurements showed that higher concentrations of acetic acid improve the conductivity beyond this effect, suggesting in addition to standard dilution effects the occurrence of Grotthuss diffusion in high acid-to-base ratios. The results here will potentially help designing novel electrolytes and proton conducting systems, which can be exploited in a variety of applications