Solvability of the system of equations of one-dimensional motion of a heat-conducting two-phase mixture

We prove the local solvability of the initial boundary-value problem for the system of equations of one-dimensional nonstationary motion of a heat-conducting two-phase mixture (gas plus solid particles). For the case in which the real densities of the phases are constant, we establish the solvability “in the large” with respect to time.     

Electrochemical Synthesis of 2,5-Dichloroaniline

A procedure was proposed for electrochemical reduction of 2,5-dichloronitrobenzene to 2,5-dichloroaniline in aqueous-ethanolic solution of sulfuric acid. The procedure for preparing 2,5-dichloroanilinium sulfate was optimized. The influence exerted by the cathode material, nature and amount of the organic solvent, sulfuric acid concentration, and electrolysis temperature on the yield and quality of the target product was discussed.     

Solvability of the boundary-value problem for equations of one-dimensional motion of a two-phase mixture

For the system of equations of one-dimensional nonstationary motion of a heat-conducting two-phase mixture (of gas and solid particles), the local solvability of the initial boundary value problem is proved. For the case in which the intrinsic densities of the phases are constant and the viscosity and the acceleration of the second phase are small, we establish the “global” (with respect to time) solvability and the convergence (as time increases unboundedly) of the solution of the nonstationary problem to the solution of the stationary one.     

Forensic Identification of Dyes in Ballpoint Pen Inks Using LC–ESI–MS

The aim of this work was to develop a new technique using flow injection analysis combined with LC–ESI–MS which allows identification of dyes in ballpoint pen inks. A sample preparation procedure for the extraction of dyes from ballpoint pen strokes has been developed. The characteristic group of ions for each sample of 21 studied ballpoint pen inks corresponding to the present dyes has been determined using flow injection method. LC separation conditions for identified dyes have been optimized on reversed-phase sorbent based on silica gel. The best composition of the mobile phase for the dyes mixture LC separation was 0.1% aqueous formic acid and acetonitrile. Detection of dyes was carried out using mass spectrometry with electrospray ionization in positive and negative modes after reversed-phase liquid chromatography separation. Dye composition of ink was additionally confirmed comparing the data obtained from the literature. Flow injection analysis allows obtaining intensive ions of unknown strokes. It is difficult to get this information using only chromatographic methods, because dyes peak intensity can be low and noise of basic line high. Flow injection method allows distinguishing the analyzed 21 ballpoint pens by determining a characteristic set of dyes. The developed flow injection technique is very simple and quick. As a result, a novel approach for the identification of dyes in the ballpoint pen inks by flow injection analysis with LC–ESI–MS and UV detection without using standard dye samples has been established. It can be an effective alternative to the existing LC–DAD–MS and IR spectroscopy methods.     

Electrochemical methoxylation of alkenyldichloroanisoles

Electrochemical oxidation of chlorinated alkenylanisoles in anhydrous methanol was studied.     

Improvement of a Process for Synthesis of Thioglycolic Acid

An environmentally clean process was proposed for synthesis of thioglycolic acid by condensation of monochloroacetic acid with sodium disulfide, followed by electrochemical reduction of the resulting mixture.     

Asymptotics of the spectrum of nonsmooth perturbations of differential operators of order 2m

On a finite closed interval, we obtain the asymptotics of the eigenvalues of a differential operator of order 2m perturbed by a differential operator of order 2m ? 2 given by a quasidifferential expression. We also consider the case of multiple eigenvalues.     

Spectral asymptotics for nonsmooth perturbations of the harmonic oscillator

We obtain the spectral asymptotics of a nonsmooth perturbation of the one-dimensional harmonic oscillator. We use the technique of perturbation theory which is based on an asymptotic presentation of the part of the kernel of the nonperturbed operator resolvent in some neighborhood of an eigenvalue.