Study of microstructure and thermal properties of the low-melting Bi–In eutectic alloys

Journal of Thermal Analysis and Calorimetry - This study reports the results of microstructure and thermal analysis of low-melting Bi–In alloys with potential for commercial application in...     

Electrochemistry of hydrogen peroxide reduction reaction on carbon paste electrodes modified by Ag- and Pt-supported carbon microspheres

Journal of Solid State Electrochemistry - A simple and facile hydrothermal methodology for preparation of carbon microspheres supported with silver or platinum is presented. Electrocatalytic...     

Spectroscopic Determination of the Electronic Structure of a Uranium Single-Ion Magnet

Early actinide ions have large spin-orbit couplings and crystal field interactions, leading to large anisotropies. The success in using actinides as single-molecule magnets has so far been modest, underlining the need for rational strategies. Indeed, the electronic structure of actinide single-molecule magnets and its relation to their magnetic properties remains largely unexplored. A uranium(III) single-molecule magnet, [U^III{SiMe₂NPh}₃-tacn)(OPPh₃)] (tacn=1,4,7-triazacyclononane), has been investigated by means of a combination of magnetic, spectroscopic and theoretical methods to elucidate the origin of its static and dynamic magnetic properties.     

Electrochemical performance of sol-gel-made Na2Ti3O7 anode material for Na-ion batteries

Journal of Solid State Electrochemistry - Nanocrystalline Na2Ti3O7 material is prepared by a newly developed sol-gel procedure. The sol-gel made Na2Ti3O7 calcined at 500 °C possesses...     

Gas chromatographic determination of perfluorocarboxylic acids in aqueous samples – A tutorial review

Determination of perfluorocarboxylic acids (PFCAs) by gas chromatography (GC) has been undertaken since 1980. However, only small number of studies can be found in the literature due to the major drawbacks associated with the GC determination of PFCAs such as high detection limits, a small range of analytes, long analysis time, and laborious derivatization prior to chromatographic separation. Liquid chromatography-tandem mass spectrometry (LC–MS²) can overcome these limitations of GC, and therefore has become the method of choice for the determination of PFCAs since 2001. Nevertheless, GC as a low-cost and commonly available analytical technique should not be ignored because of its inherent advantage over LC to identify PFCA isomers in environmental and biological matrices owing to its high-resolution power. In addition, GC provides an opportunity to crosscheck LC–MS² results that are often suspicious due to background contamination. This tutorial provides an overview of GC methods that have been used for the determination of PFCAs after derivatization. Moreover, performance characteristics of GC–MS are compared with that of LC–MS². PFCAs in aqueous samples were determined by both analytical techniques, and two sets of measurements were compared using the Bland-Altman plot. For both methods, reasons for false-positive and false-negative results (overestimation and underestimation of the PFCA concentration, respectively) are discussed, and accordingly some advice is offered on how to avoid erroneous results. Finally, major applications of GC and its future perspectives for the determination of PFCAs are discussed.     

Water soluble chromone Schiff base derivatives as fluorescence receptor for aluminium(III)

A novel water-soluble chromone Schiff base derivatives bearing polyhydroxylated moiety were prepared and applied for specific recognition of metal ions in aqueous medium. Their selective fluorescence response to Al(III) over a variety of other biologically important metal ions were demonstrated. Electronic parameters of the sensors were also studied by quantum chemical computations.     

Combined swept region and intersection‐based single‐material remapping method

A typical arbitrary Lagrangian–Eulerian algorithm consists of a Lagrangian step, where the computational mesh moves with the fluid flow; a rezoning step, where the computational mesh is smoothed and repaired in case it gets too distorted; and a remapping step, where all fluid quantities are conservatively interpolated on this new mesh. In single‐material simulations, the remapping process can be represented in a flux form, with fluxes approximated by integrating a reconstructed function over intersections of neighboring computational cells on the original and rezoned computational mesh. This algorithm is complex and computationally demanding – Therefore, a simpler approach that utilizes regions swept by the cell edges during rezoning is often used in practice. However, it has been observed that such simplification can lead to distortion of the solution symmetry, especially when the mesh movement is not bound by such symmetry. For this reason, we propose an algorithm combining both approaches in a similar way that was proposed for multi‐material remapping (two‐step hybrid remap). Intersections and exact integration are employed only in certain parts of the computational mesh, marked by a switching function – Various different criteria are presented in this paper. The swept‐based method is used elsewhere in areas that are not marked. This way, our algorithm can retain the beneficial symmetry‐preserving capabilities of intersection‐based remapping while keeping the overall computational cost moderate.