Natural luminescence and anomalous fading in K-feldspar

This study investigated the relationship between the natural luminescence intensity, the amplitude of anomalous fading and the apparent IRSL age of a suite of feldspar single grains. Correlating natural luminescence with fading may simplify the identification of weakly to non-fading feldspars grains in sediments. In our single grain experiments, the mean fading corrected IRSL age obtained from a small population of bright grains is close to the expected depositional age of the sediment investigated. It is proposed that in dating programs, more attention should be given to bright feldspar grains as they are the most stable grains in the population.     

Electrochemical reactivity of In-Pb solid solution as a negative electrode for rechargeable Mg-ion batteries

A composite In-Pb:carbon was successfully synthetized by a two-step mechanochemical synthesis in order to obtain an adequate particles size and structure to investigate the electrochemical reactivity of the In-Pb solid solution towards Mg.A potential synergetic coupling of electroactive elements In and Pb was examined using electrochemical and ex situ X-ray diffraction analyses.The potential profile of the solid solution indicates the formation of Mg₂Pb and Mg In.However,the diffraction study suggests a peculiar electrochemically-driven amorphization of Mg In during the magnesiation,in strong contrast to Mg In crystallization in In-based and In Bi-based electrodes reported in the literature.Combining In and Pb favors the amorphization of Mg In and a high first magnesiation capacity of about 550 m Ah g^-1,but is thereafter detrimental to the material’s reversibility.These results emphasize the possible influence of electrochemically-driven amorphization and crystallization processes on electrochemical performance of battery materials.     

Natural Eutectic Solvent Mixture of l-Menthol/Malonic acid (4 : 1) and Its Ibuprofen Solution: Thermal and Physical Characterizations and NMR Studies of Molecular Interaction

A eutectic mixture of L-menthol and malonic acid, Me / MA (4 : 1), was characterized by calorimetry and other physical measurements. The new deep eutectic solvent (m.p. 6 °C) solvates 338 mg of ibuprofen per mL, and the solution is stable in a wide temperature range. Strategies of NMR titration used in supramolecular chemistry were employed to explore binding forces between the eutectic constituents as well as solute-solvent interaction in ibuprofen solution. Even in acetonitrile, Me ₄ MA is formed through a hydrogen-bonding network, where the constituents act as hydrogen donors and acceptors at the same time. The estimated association constant is around 30 M⁻¹; the binding forces are enough to build the eutectic mixture at high concentrations. The aggregate Me ₄ MA forms a molecular complex with ibuprofen in acetonitrile as a result of the cooperative effect of the constituents. In addition, van der Waals interactions are operative between ibuprofen and menthol in the saturated IB - Me / MA (4 : 1) solution.