Investigation of the mechanisms of the onset of instability in weakly conduction media in electric fields

The initial stable state (of rest or laminar flow) of a weakly-conducting viscous multicomponent fluid in a plane channel, whose walls are electrodes with electrochemical properties varied in the process of investigation, are considered. The conventional electrohydrodynamic models of a medium with one or two charged particle components, whose concentrations are low compared with that of the neutral particles of the carrying fluid, are used. The time-dependent two-dimensional problem of the formation of the medium structure in the inter-electrode space after the voltage from the electrodes has been turned on is numerically solved. The obtained distributions of the Coulomb forces acting on the medium make it possible to develop several possible scenarios of the disturbance development, similar with those known in fluid dynamics. The realization of any of these scenarios considerably depends on the conditions at the electrode surfaces.     

Strong Polynomial Completeness of Almost All Quasigroups

Mathematical Notes - In the paper, it is proved that almost all quasigroups are strongly polynomially complete, i.e., are not isotopic to quasigroups that are not polynomially complete.     

N,N-Dimethylethylenediamine in direct and direct template syntheses of Cu(II)/Cr(III) complexes

Four new heterometallic Cu(II)/Cr(III) complexes with N,N-dimethylethylenediamine (dmen) and its novel Schiff-base derivatives, N′-[(1Z)-3-amino-1,3-dimethylbutylidene]-N,N-dimethylethane-1,2-diamine (dmenac) and N′-((1Z)-3-{[2-(dimethylamino)ethyl]amino}-1,3-dimethylbutylidene)-N,N-dimethylethane-1,2-diamine (dmen₂ac), have been easily prepared by self-assembly and characterized by spectroscopic methods and single crystal X-ray analysis. The structures of all the complexes are assisted by numerous hydrogen bonds that provide a web of interactions and mould the supramolecular architectures of the compounds. Variable-temperature (1.8–300 K) magnetic susceptibility measurements reveal Curie-Weiss paramagnetic behavior of all the compounds, supported by EPR studies.     

On ionization of electronically excited molecules in hydrocarbon combustion under strong electric field

We suggest an explanation for the disagreement between the theoretically calculated and experimentally measured data concerning the electric current detected in diagnostic devices (like electric probes or flame ionization detectors, FID) used for investigation of the ionization processes in high-temperature mixtures of molecular gases at normal pressure. The conclusions are in good agreement with experimental data under the condition that the strong electric field produced by the electrodes of the diagnostic devices induces additional ionization of electronically excited molecules, which are always present in combustion products.     

Decomposition of organic compounds by irradiation with light

Summary It has been shown that organic halogen compounds completely decompose under the light of a xenon lamp. Decomposition products include hydrogen hah'de, free halogen, free carbon, carbon monoxide, gaseous hydrogen. The rate and completeness of the photo-decay depends on the nature of both the compound and the halogen. The minimum time of decay was observed for iodo-derivatives, the maximum for fluoro-derivatives. The rate of photo-decay was found to be considerably greater for coloured substances.

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Zusammenfassung Organische Halogenverbindungen zersetzen sich im Licht einer Xenonlampe. Unter den Zersetzungsprodukten finden sich Halogenwasserstoff, freies Halogen, freier Kohlenstoff, Kohlenmonoxid und gasförmiger Wasserstoff. Das Ausmaß und die Vollständigkeit der Photozersetzung hängt von der Art der Verbindung und der Art des Halogens ab. Die kürzeste Zersetzungszeit wurde bei Jodderivaten, die längste bei Fluorderivaten beobachtet. Die Geschwindigkeit der Zersetzung ist bei gefärbten Substanzen erheblich größer.

     

Electrification of weakly conducting liquids in the neighborhood of a wall

The problem of the generation of an uncompensated electric space charge in weakly conducting viscous fluid channel flows in which the medium interacts electrochemically with an interface is investigated for an arbitrary relation between the mobilities of the charged particles of different kinds. New models of the electrochemical surface processes are considered. The effect of the parameters of these processes on the electrification current and on the time taken by the electric parameters of the medium is studied to reach saturation. The possibility of the generation of strong induced electric fields on the interface is justified theoretically, two basic parameters affecting the strength of these fields are determined, and an explanation of the discharge process observed in the experiments in the form of local fluid glow zones is proposed.