Light-Ion Linear Accelerator for the NICA Project

Physics of Particles and Nuclei Letters - A joint team from the Joint Institute for Nuclear Research (JINR) (Dubna, Russia) and Bevatech GmbH (Frankfurt-am-Main, Germany) has been developing a new...     

The mechanism of action and the synergistic effect of nitrogenand phosphorus-containing fire retardants in fire protection and wood and peat fire suppression

The factors exerting a significant influence on the termination of the combustion of natural materials (wood and peat) were studied with the use of synthetic nitrogen- and phosphorus-containing fire retardants with different efficiencies. With the use of a mathematical experimental design method, it was confirmed that the inhibition of gas-phase radical processes by volatile nitrogen-containing products is the predominant process of combustion suppression. It was found that the synergism of the nitrogen–phosphorus flame retardants is determined by their complex action: phosphorus mainly enters into organomineral structures in a the condensed phase, and nitrogen inhibits reactions in a gas phase.     

Storage ring with longitudinal magnetic field LEPTA (Stellatron)

The project of the Low Energy Particle Toroidal Accumulator (LEPTA) is dedicated to the construction of a positron storage ring with electron cooling of positrons circulating in the ring. Such a specific feature of LEPTA automatically enables it to be a generator of positronium (Ps) atoms, which appear in the recombination of positrons with cooling electrons inside the cooling section of the ring. The project has the following goals: particle dynamics in the modified betatron, electron cooling with a circulating beam, positronium generation in flight, positronium physics, and feasibility of antihydrogen generation in flight. All key elements of the ring—the kicker, electron beam injection system, helical quadrupole, septum magnet—have been tested, and the expected design parameters have been achieved for these elements. The construction of LEPTA has been completed, and the circulating electron beam has been achieved. This paper discusses the issues of particle dynamics in such an accelerator, the results of numerical simulation and experimental findings of the research into beam dynamics, measurement of betatron number and beam lifetime.     

Kinetics of fiber impregnation by a binder. Gradient generalization of Navier–Stokes–Darcy equations

A model of polymer composition material that is composed of a unidirectional fiber and binder has been considered. The space between two neighboring filaments of fibers is considered as a capillary along which the binder propagates during impregnation. In order to describe the flow process, a gradient generalization of the Navier–Stokes equation has been suggested. A corrected model of the flow of binder in the capillary-porous space of a unidirectional fiber material is developed on its basis. In particular cases, the found solution coincides with the Navier–Stokes–Darcy equations and conventional Navier–Stokes equation. The model that has been developed allows the refinement of the nonclassical effect of the existence of two boundary layers that appear during flow and may prevent it.     

Condensed imidazo-1,2,4-azines 22. Alkylation of 5H-imidazo[1,2-b]-1,2,4-triazepin-4-ones

Substituted 5H-imidazo[1,2-b]-1,2,4-triazepin-4-ones react with alkyl (alkenyl) halides, 2-chloroethanol, glycerin dichlorohydrin, haloacetic acids, the methyl ester and amide of monochloroacetic acid in a methanol-sodium methylate system to form N₍₅₎-alkylation products, and with hydroxylamino-O-sulfonic acid to form 5-aminoimidazo[1,2-b]-1,2,4-triazepin-4-one.For Communication 21, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 234–236, February, 1990.