Binary and ternary alkali polyphosphates (MPO3, M = Li,Na, K) for thermal energy storage

Journal of Thermal Analysis and Calorimetry - Up-to-date, solar salt (a mixture of 60 mass% NaNO3 and 40 mass% KNO3) is practically the only media for thermal energy storage (TES) in concentrated...     

The Impact of Apple Variety and the Production Methods on the Antibacterial Activity of Vinegar Samples

Apple vinegar is a natural product widely used in food and traditional medicine as it contains many bioactive compounds. The apple variety and production methods are two factors that play a major role in determining the quality of vinegar. Therefore, this study aims to determine the quality of apple vinegar samples from different varieties (Red Delicious, Gala, Golden Delicious, and Starking Delicious) prepared by three methods using small apple pieces, apple juice, and crushed apple, through determining the physicochemical properties and antibacterial activity of these samples. The antibacterial activity was studied against five pathogenic bacteria: Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli (ATB: 57), Escherichia coli (ATB: 97), and Pseudomonas aeruginosa, using two methods, disk diffusion and microdilution, for determining the minimum inhibitory concentrations and the minimum bactericidal concentrations. The results of this study showed that the lowest pH value was 3.6 for Stark Delicious, obtained by liquid fermentation, and the highest acetic acid values were 4.7 and 4% for the vinegar of Red Delicious and Golden Delicious, prepared by solid fermentation, respectively. The results of the antibacterial activity showed considerable activity of apple vinegar on the tested strains. Generally, the Staphylococcus aureus strain appears less sensitive and Pseudomonas aeruginosa seems to be very sensitive against all samples, while the other strains have distinct sensitivities depending on the variety studied and the method used. A higher antibacterial activity was found in vinegar obtained by the apple pieces method and the Red Delicious variety, with a low MIC and MBC recorded, at 1.95 and 3.90 µL/mL, respectively. This study has shown that the choice of both apple variety and production method is therefore an essential step in determining and aiming for the desired quality of apple vinegar.     

K2M(H2P2O7)2·2H2O (M = Ni,Cu, Zn): ortho­rhom­bic forms and Raman spectra

The crystal structures of three isotypic ortho­rhom­bic dihydrogendiphosphates, namely dipotassium copper(II)/nickel(II)/zinc(II) bis­(dihydrogendiphosphate) dihydrate, K₂M(H₂P₂O₇)₂·2H₂O (M = Cu, Ni and Zn), have been refined from single‐crystal data. The M²⁺ and K⁺ cations are located at sites of m symmetry, and the P atoms occupy general positions. These compounds also exist in triclinic forms with very similar structural features. The structures of both forms are compared, as well as the geometry of the MO₆ octa­hedron, which is considerably elongated towards the water mol­ecules for M = Ni and Cu. Such elongation has not been observed among the other representatives of the family. A Raman study of the whole series K₂M(H₂P₂O₇)₂·2H₂O (M = Mn, Co, Ni, Cu, Zn and Mg) is reported.     

The Relationship between the Relative Solvating Power of Electrolytes and Shuttling Effect of Lithium Polysulfides in Lithium–Sulfur Batteries

Relative solvating power, that is, the ratio of the coordination ratios between a solvent and the reference solvent, was used to probe the quantitative structure–activity relationship of electrolyte solvents and the lithium polysulfide (LiPS) dissolution in lithium–sulfur batteries. Internally referenced diffusion‐ordered nuclear magnetic resonance spectroscopy (IR‐DOSY) was used to determine the diffusion coefficient and coordination ratio, from which the relative solvating power can be easily measured. The higher the relative solvating power of an ethereal solvent, the more severe will be the LiPS dissolution and the lower the coulombic efficiency of the lithium–sulfur battery. A linear relationship was established between the logarithm of relative solvating power of a solvent and the degree of LiPS dissolution, rendering relative solvating power an important parameter in choosing the electrolyte solvent for lithium–sulfur batteries.     

Direct Chemical Fine‐Tuning of Electronic Properties in Sc2Ir6−xPdxB

Crystal orbital Hamilton population (COHP) bonding analysis has predicted that ScPd₃B_0.5 is the least stable compound of the entire series Sc₂Ir_6?xPd_xB. Here, we report a systematic study of Sc₂Ir_6?xPd_xB (x=3, 5 and 6) by means of ¹¹B nuclear magnetic resonance (NMR), Knight shift (K) and nuclear spin‐lattice relaxation rate (1/T₁). NMR results combined with theoretical band structure calculations provide a measure of s‐ and non‐s‐character Fermi‐level density of states. We present direct evidence that the enhanced s‐state character of the Fermi level density of states (DOS) in ScPd₃B_0.5 reduces the strength of the B 2p and Pd 4d hybridized states across the entire Sc₂Ir_6?xPd_xB series. This hybridization strength relates to the opening of a deep pseudogap in the density of states of Sc₂IrPd₅B and the chemical bonding instability of ScPd₃B_0.5. This study is an experimental realization of a chemical fine‐tuning of the electronic properties in intermetallic perovskites.     

Filler segmentation of SEM paper images based on mathematical morphology

Recent developments in microscopy and image processing have made digital measurements on high-resolution images of fibrous materials possible. This helps to gain a better understanding of the structure and other properties of the material at micro level. In this paper SEM image segmentation based on mathematical morphology is proposed. In fact, paper models images (Whatman, Murillo, Watercolor, Newsprint paper) selected in the context of the Euro Mediterranean PaperTech Project have different distributions of fibers and fillers, caused by the presence of SiAl and CaCO3 particles. It is a microscopy challenge to make filler particles in the sheet distinguishable from the other components of the paper surface. This objectif is reached here by using switable strutural elements and mathematical morphology operators.     

Rapid syntheses of (±)-pterocarpans and isoflavones via the gold-catalyzed annulation of aldehydes and alkynes

(±)-Pterocarpan and analogues (4a-c) have been synthesized efficiently via the annulation of salicylaldehydes (1a, 1b and 1c) and o-methoxymethoxylphenylacetylene (2a), followed by a one-pot reduction and acidic cyclization of the ketones (3a-c). In addition, isoflavone derivatives (5a-c) have been synthesized rapidly, in two steps, via the annulation of salicylaldehyde (1a) and arylacetylenes (2b, 2c and 2d), followed by IBX/DMSO oxidation of the isoflavanones (3d, 3e and 3f).     

Analytical potential energy functions and theoretical spectroscopic constants for MX/MX− (MGe,Sn, Pb; XO,S, Se,Te, Po) and LuA (AH,F) systems: Density functional theory calculations

The molecular spectroscopic constants for the chalcogenide complexes MX (M?Ge, Sn, Pb; X?O, S, Se, Te, Po) and their corresponding MX^? anions are presented with the LSDA/SDD, B1LYP/SDD, and B3LYP/SDD methods. Although many methods were attempted, only the most promising results are reported. We show that the best results are obtained by LSDA/SDD calculations, and thus this method is emphasized as an illustrative example of our methodology. The potential energy curves and physical property characterizations for X¹ ∑⁺ state of LuH and LuF are presented with a variety of density functional theory (DFT) methods. Comparisons with wave function‐based treatments (HF, MP2, CCSD, QCISD) are made in addition to experimental correlations. We show that the best results are obtained by the B3LYP/SDD method for LuH, and the MPW1PW91/SDD method for LuF. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

A facile synthesis of new tetrahydropyrido[4,3-d]pyrimidine derivatives

The one-pot reaction of 1-benzylpiperidin-4-one with different nitriles in the presence of triflic anhydride affords substituted tetrahydropyrido[4,3-d]pyrimidines. Reaction with methylthiocyanate forms the corresponding methylthio substituted tetrahydropyridopyrimidines which can be easily converted into dimethoxy and dicarbonyl derivatives.     

Topologically Algebraic Algebras

We show that a locally convex algebra is topologically algebraic if, and only if, it is algebraic.Thanks are offered to Professor M. Oudadess for many remarks which allowed an improvement of the first version of this paper. We are also indebted to Professor A. Mallios for valuable suggestions.