The energies of dissociation of the N—O bonds in pyridine 1-oxide derivatives

The enthalpies of combustion of some pyridine derivatives in the solid state have been measured by precision bomb calorimetry, and their enthalpies of formation have been calculated. The enthalpies of sublimation of these compounds have been determined from the experimental temperature dependences of saturated vapor pressure using the Clausius-Clapeyron equation. The enthalpies of combustion, formation, and sublimation are the following (kJ mol^–1): -3360.9±2.1, -0.5±2.1, and 79.1±1.3, respectively, for 4-methylpyridine 1-oxide; -2551.0±1.7, 11.7±1.7, and 89.1±2.5, respectively, for 4-nitropyridine 1-oxide;-2355.6±1.3, 102.1±1.3, and 106.3±2.9 for 2,4,6-trinitropyridine 1-oxide; and -2287.6±1.3, 34.3±1.3, and 101.7±2.9 for 2,4,6-trinitropyridine. The enthalpies of formation in the solid state and the enthalpies of sublimation of pyridine derivatives obtained together with the literature data allowed the energies of dissociation of the donor-acceptor N—O bonds in pyridine 1-oxides to be calculated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 660–662, April, 1995.     

Observation of the decaya 2 − (1320)→π − η′

The reaction ^– C ^– C has been studied at 36 GeV/c. A clear signal for the decaya ₂ ^– (1320) ^– · is observed in the ^– mass spectrum. The measured ratio of branchings is BR (a ₂ ^{– –} )/BR(a ₂ ^{– –} );(3.4±0.8±0.5)·10^–2.     

Shock Wave Structure in a Weakly Ionized Ion Plasma Containing Charged Particles

The shock wave structure in a three-component weakly ionized plasma containing fine metal particles (macroparticles) is considered. The particles are ionized due to thermionic emission and the ejected electrons adhere to molecules of the neutral carrier gas assumed to be electronegative. The resulting ion plasma contains charged components with sharply different masses which are differently decelerated in the shock wave. This leads to charge separation and the generation of self-consistent electric fields which in turn affect the motion of the charged components.__________Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, 2005, pp. 179–188.Original Russian Text Copyright © 2005 by Bityurin and Klyuchnikov     

Three-dimensional static problem for an elliptical crack in an elastic body with initial stress

Conclusions Thus, the influence of the initial stress on the displacement distribution in the crack plane is significant. In [6], it was concluded that, for a shear crack, it is impossible to show in the general case that the initial stress has no influence on the stress-intensity coefficients (which is the case for a normal-rupture crack). For the example of an elliptical shear crack, it is shown that the initial stress influences the stress distribution close to the crack and hence the stress-intensity coefficient, in contrast to the plane and axisymmetric problems.Close to the value of ₁ equal to the surface instability of the half space, as follows from a consideration of quantitative dependences, its influence is sharply expressed.The stress and displacement distribution in a body with initial stress (y ₃0) will differ from the corresponding distribution in a linear isotropic and transversally isotropic elastic body with no initial stress.Institute of Mechanics. Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 20, No. 10, pp. 22–31, October, 1984.     

Radial scanning diagnostics of bremsstrahlung and line emission in T-10 plasma

The paper describes the scanning spectroscopic diagnostics designed for measurement of line integrated plasma radiation in two visible spectral ranges. This diagnostic system is aimed at measuring the bremsstrahlung absolute values and profile with high spatial resolution. The bremsstrahlung absolute values are used to determine the value and radial distribution of effective plasma ion charge Z _eff(r) in T-10 discharges. The importance of Z _eff measurement is due to its strong influence on plasma heating, confinement, and stability. The spatial distribution of emission for one of the chosen spectral lines is measured simultaneously with bremsstrahlung. The spatial resolution of measurements is ~1 cm, and the temporal resolution is up to 10 ms. The spectral equipment and methods for its calibration are described. Examples of line integrated brightness distribution in a “continuum window” of 5236 ± 6 Å and brightness of the lines C⁵⁺ (5291 Å), He¹⁺ (4686 Å), and D_β (4861 Å) are given. Flattening of the bremsstrahlung brightness profile in the central region of the plasma column in some discharges with sawtooth oscillations in the T-10 is observed. The measured effective ion charge profiles in ohmic discharges with high plasma density and low discharge currents demonstrate accumulation of light impurities at the column axis; as a consequence, quenching of sawtooth oscillations in some discharges is observed. The developed diagnostics provides necessary data for investigation of heat, particle, and current transport in the plasma of the T-10. Successful application of the obtained data on Z _eff(r) for investigation of geodesic acoustic modes of plasma oscillations in the T-10 should be specially noted.     

Preparation and vulcanizing properties of 1,3,5-trinitrosobenzene

A procedure was developed for preparing a new trifunctional vulcanizing agent for unsaturated rubber composites, 1,3,5-trinitrosobenzene; its suitability as an additive to rubber-substrate adhesive formulations was examined.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 8, 2004, pp. 1395–1397.Original Russian Text Copyright © 2004 by O. Klyuchnikov, Khairutdinov, Ya. Klyuchnikov.