A thermogravimetric study of praseodymium(III), neodymium,samarium, gadolinium and holmium acetates,benzoates and abietates

The thermal decompositions of the acetates of Pr, Nd, Sm, Gd and Ho have been investigated using thermogravimetry and differential thermal analysis, together with infrared spectroscopy and X-ray diffraction. The thermal decompositions of the acetates of the rare earth elements exhibit several stages, depending upon both the number of crystal water molecules in the acetates and the rare earth element behaviour. Experiments with the benzoates and abietates of Pr, Nd, Sm, Gd and Ho indicate some correlations in the thermal decompositions of carboxylates of the rare earth elements.

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Zusammenfassung Die thermische Zersetzung der Acetate von Pr, Nd, Sm, Gd und Ho wurde durch Thermogravimetrie und Differentialthermoanalyse in Verbindung mit der Infrarotspektroskopie und Röntgendiffraktionsmethode untersucht. Die thermische Zersetzung der Acetate der seltenen Erden verläuft in mehreren Stufen, welche sowohl von der Zahl der Kristallwassermoleküle in den Acetaten als auch von dem Verhalten der seltenen Erden abhängen. Experimente mit den Benzoaten und Abietaten von Pr, Nd, Sm, Gd und Ho zeigen gewisse Abhängigkeiten von der thermischen Zersetzung der Carboxylate der seltenen Erden.

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Résumé La décomposition thermique des acétates de Pr, Nd, Sm, Gd et Ho a été étudiée par thermogravimétrie et analyse thermique différentielle ainsi que par spectroscopie infrarouge et diffraction des rayons X. La décomposition thermique des acétates de terres rares se produit en plusieurs étapes qui dépendent à la fois du nombre de molécules d'eau de cristallisation de l'acétate et du comportement de l'élément des terres rares considéré. Des expériences effectuées avec les benzoates et abiétates de Pr, Nd, Sm, Gd et Ho montrent que la décomposition thermique des carboxylates dépend des éléments de terres rares considérés.

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Pr, Nd, Sm, Gd , , - - . , , . Pr, Nd, Sm, Gd .

     

A penalty method for numerically handling dispersive equations with incompatible initial and boundary data

This article is the numerical counterpart of a theoretical work in progress Qin and Teman, Applicable Anal (2011), 1–19, related to the approximation of evolution hyperbolic equations with incompatible data. The Korteweg‐de Vries and Schrödinger equations with incompatible initial and boundary data are considered here. For hyperbolic equations, the lack of regularity (compatibility) is known to produce large numerical errors which propagate throughout the spatial domain, destroying convergence. In this article, we numerically test the effectiveness of the penalty‐based method proposed in Qin and Teman, Applicable Anal (2011), 1–19, which replaces the hyperbolic equations with incompatible data by a system with compatible data. We observe that convergence is increased. As explained in the text, in the case of the Schrödinger equation, the impact of incompatible (nonregular) data is most severe, and the authors are not aware of any other method that can handle such severe incompatible data. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2011     

Nitrosylsulfuric acid as an oxidant in the synthesis of 3,5-diarylisoxazoles

By six examples, it was demonstrated that nitrosylsulfuric acid can be successfully used for oxidation of 3,5-diaryl-4,5-dihydroisoxazoles to the corresponding 3,5-diarylisoxazoles. If the starting isoxazolines contain the aromatic substituents activated towards electrophilic substitution, nitration of both newly formed isoxazole and substituted benzene rings occurred.     

Research of Nanostructured Carbon Felt Materials as Electrodes of Vanadium Flow Batteries

Russian Journal of Electrochemistry - Flowing vanadium batteries are gaining great popularity in the world and are already ahead of lead-acid batteries in terms of installed capacity, but are far...     

Syntheses of chiral fused 4,5-diazafluorene–bis(nopinane) derivatives

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Integral operators commuting with dilations and rotations in generalized Morrey-type spaces

We find conditions for the boundedness of integral operators $K$ commuting with dilations and rotations in a local generalized Morrey space. We also show that under the same conditions, these operators preserve the subspace of such Morrey space, known as vanishing Morrey space. We also give necessary conditions for the boundedness when the kernel is non-negative. In the case of classical Morrey spaces, the obtained sufficient and necessary conditions coincide with each other. In the one-dimensional case, we also obtain similar results for global Morrey spaces. In the case of radial kernels, we also obtain stronger estimates of $Kf$ via spherical means of $f$. We demonstrate the efficiency of the obtained conditions for a variety of examples such as weighted Hardy operators, weighted Hilbert operator, their multidimensional versions, and others.     

Hamiltonian Formalism for the Problem of Optimal Motion Control under Multiple Criteria

Doklady Mathematics - This paper describes methods for optimizing solutions to problems of controlled dynamics under multiple criteria. Such problems are usually solved by reduction to scalarized...     

Homogenization methods to approximate the effective response of random fibre-reinforced Composites

In this article a fibre-reinforced composite material is modelled via an approach employing a representative volume element with periodic boundary conditions. The effective elastic moduli of the material are thus derived. In particular, the method of asymptotic homogenization is used where a finite number of fibres are randomly distributed within the representative periodic cell. The study focuses on the efficacy of such an approach in representing a macroscopically random (hence transversely isotropic) material. Of particular importance is the sensitivity of the method to cell shape, and how this choice affects the resulting (configurationally averaged) elastic moduli. The averaging method is shown to yield results that lie within the Hashin–Shtrikman variational bounds for fibre-reinforced media and compares well with the multiple scattering and (classical) self-consistent approximations with a deviation from the latter in the larger volume fraction cases. Results also compare favourably with well-known experimental data from the literature.