Calculation of a transport current from a nozzle with two-phase flow in the presence of a corona discharge

The operation of a source of charged aerosol particles which consists of a supersonic nozzle, a corona-forming needle-shaped electrode, and a device for injecting liquid droplets into a gas flow is considered. A theoretical model for two-dimensional, two-phase flow in the nozzle is considered. An algorithm of numerical calculation of such a flow is developed, and results of calculations of the electric transport current from the nozzle are given. Institute of Mechanics, Moscow State University, Moscow 117192. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 6, pp. 102–109, November–December, 1998.     

Image of rays that have passed through a stationary phase-distorting medium

Images obtained through stationary phase-distorting media are investigated in this paper. It is shown that the quality of the recorded images depends on the conditions of light beam limitation. Qualitative results and quantitative dependences of the contrast of the image being recorded through a phase-distorting medium on the magnitude of the aperture orifice are presented. A method is proposed for improving the image quality of objects being recorded through smooth phase-distorting stationary media, which is efficient for both coherent and noncoherent exposure.     

Distortion deformations in the B2-R phase transition in titanium nickel alloys

Based on x-ray analysis, we have calculated the lattice distortions in Ti-Ni-Me (Me=Rh, Co, Fe) alloys during the B2-R phase transition. We find that, during the transition, the deformation decreases as the concentration of the alloying component increases in Ti-Ni-Rh and Ti-Ni-Co. No such correlation is observed in the Ti-Ni-Fe alloys. Tomsk State Architecture-Construction Academy. V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 95–100, February, 1997.     

Thermal and acoustic effects in the γ irradiation of amorphous Ti−Ni−Cu alloys

The influence of γ radiation on the thermal and acoustic effects in amorphous Ti−Ni−Cu alloys is investigated. On the basis of the results obtained, a mechanism by which γ quanta affect the structure of amorphous metal alloys (AMA) is proposed. In the interaction of a γ flux with AMA, the energy is redistributed and accumulates at intercluster boundaries. Then, when restructuring of all the intercluster boundaries is complete, restructuring of locally regular clusters begins; this leads, in turn, to restructuring of the intercluster boundaries. Further increase in radiation dose again triggers the mechanism of intercluster-boundary restructuring, but at a different level. This is evident in the oscillatory fluctuation in the activation energy of relaxation processes and of phase transformation from amorphous to crystalline structure. Tomsk State Architectural and Building Academy. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 75–80, September, 1996.     

Experimental study of polarization bremsstrahlung from small-grained polycrystals

The spectrum of polarization Bremsstrahlung is measured in backscattering geometry for 7-MeV electrons and a polycrystalline Ni foil without texture. The average size of grains in the foil is 300 nm. The results show the possibility of using a new method in the diagnostics of the atomic structure of polycrystalline materials with nanosized grains. The method is based on measuring the coherent component of polarization Bremsstrahlung.     

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.     

A Sylvester–Gallai Type Theorem for Abelian Groups

Mathematical Notes - This paper provides an elementary proof of inequalities previously obtained by the operator method and having applications in additive combinatorics. The method of proof allows...     

Stability of Ultradisperse Copper in a Sulfo Cation Exchanger Matrix

The recrystallization of ultradisperse copper chemically deposited onto a sulfo cation exchanger matrix was studied by the potentiometric method. The stationary value of the electrode potential of the copper-sulfo cation exchanger composite was established during a long period of time, which depended on the ionic form of the composite (H⁺, Cu²⁺, or Na⁺), solution composition (CuSO₄, H₂SO₄, and Na₂SO₄), and solution concentration. Recrystallization was favored by copper(II) counterions, which entered the composite as a result of ion exchange, nonexchange absorption of copper sulfate, or preliminary composite transformation into the Cu²⁺ form. In the quasi-equilibrium state, the concentration of copper(II) counterions was maintained at a high level by the Donnan interfacial potential. At all the copper(II) sulfate concentrations used, the potential of the Cu²⁺/Cu ion—metal pair in the ion-exchange matrix remained at virtually the same level, which was indicative of the stable state of copper particles. In the absence of an external source of copper ions, recrystallization was significantly hindered; therefore, the potential exhibited only a slight drift. Copper ions formed in the solution of small crystals were localized in the vicinity of ionogenic matrix centers, which decreased the mobility of these particles as counterions; therefore, the dispersity of particles remained unchanged.     

Rearrangements of <Emphasis Type="Italic">N</Emphasis>-ethoxycarbonylmethyl-1,2,3,4-tetrahydroquinolinium halogenalkylates effected by sodium hydride. Synthesis of 2,3,4,5-tetrahydro-1<Emphasis Type="Italic">H</Emphasis>-3-benzazepines

Quaternary salts obtained from N-alkyl-1,2,3,4-tetrahydroisoquinolines and ethyl haloacetates or diethyl bromomalonate under the action of sodium hydride in boiling 1,4-dioxane were converted into N-alkyl-N-ethoxycarbonyl-2,3,4,5-tetrahydro-1H-3-benzazepines in 49–60% yield. From the reaction mixture by column chromatography products of β-elimination by Hofmann reaction, 2-(N-methyl-N-ethoxycarbonylmethyl)-aminomethylstyrenes were also isolated (yield 0.6–16%).