Influence of the kinematical constraints on the transverse momentum correlation features

The influence of the kinematical constraints on the transverse momentum correlation features in multiparticle processes is studied by means of thedN/(d r ₁ d r ₂) distribution,r ₁ andr ₂ being the transverse momenta of the particles entering in each pair. Using a limited transverse momentum phase space we obtain for high energy reactions a simple analytical expression fordN/(d r ₁ d r ₂). This expression, similar to a phenomenological parametrization proposed for analyzing¯pp annihilation data, served to define a correlation parameter, the non vanishing value of which is due to the energy-momentum conservation constraints.     

Reactive nitrogen species produced in water by non-equilibrium plasma increase plant growth rate and nutritional yield

Water quality, mineralization, and chemical composition, particularly pH and nitrogen compounds each, play a crucial role in plant development and growth. Treatment of water with non-equilibrium discharges results in the change of its properties and chemical composition, which in turn may affect plant growth process and subsequently agriculture produce quality. Both thermal and non-thermal discharges generated in air or in water produce a number of reactive neutral and charged species, electric fields, and ultraviolet radiation. Plasma treatment of water results in significant change of its properties like pH, oxidation–reduction potential (ORP), conductivity, and concentration of reactive oxygen and reactive nitrogen species (ROS and RNS). Here we report the results of an experimental study of the effect of water treated with different atmospheric plasmas on germination, growth rates, and overall nutritional value of various plants. In the study we have used three types of plasmas: thermal spark discharge, gliding arc discharge, and transferred arc discharge. It is shown that the effects of these plasmas on chemical composition of various types of water are qualitatively different. Non-thermal gliding arc discharge plasma results in lower (acidic) pH, and production of significant amount of oxidizing species (e.g. H₂O₂). Gliding arc discharge also causes significant acidification of water, but it is accompanied by production of reactive nitrogen species (NO, NO₂^? and NO₃^?). Spark discharge treatment results in neutral or higher (basic) pH depending on initial water composition, and production of RNS.     

Possibility of the development of explosive instability in a two-stream gravitating medium

An expression for the energy of the density wave in a multicomponent gravitating medium is obtained that is similar to an appropriate expression in electrodynamics of continua. The possibility of birth of a wave triplet including both positive and negative wave energies in a nonequilibrium gravitating medium is demonstrated. It is shown that such a resonant interaction of waves leads to the development of explosive instability. An expression for the characteristic growth time of instability within a one-dimensional model is obtained by a method developed in plasma physics. Original Russian Text ? A.S. Kingsep, Yu.A. Fridman, 2008, published in Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, 2008, Vol. 134, No. 2, pp. 273–281.     

On the number of relaxation regions in polyformaldehyde

The mechanical relaxation of a polyformaldehyde homopolymer free from surface grease and the additives normally used as stabilizers has been studied at a frequency of 10^–2 Hz in the temperature region 77–413°K. Six relaxation regions are observed on the curve of tangent of angle of mechanical losses as a function of temperature.T. G. Shevchenko Kiev State University. Translated from Mekhanika Polimerov, No. 5, pp. 925–927, September–October, 1973.     

Explosive instability in nonlinear waves in media with negative viscosity : PMM vol. 38, n 6, 1974, pp. 991–995

The propagation of a wave of a finite amplitude in a medium with a nonlinearity of the second degree and negative viscosity, is examined. It is shown that in a finite time singularities appear in the solution. The exact solution of the Cauchy problem is given for a specific case. Recently the effects of negative viscosity which cause an increase in the energy of the wave motion have been studied intensively in electrodynamics, plasma physics, the Earth's atmosphere, in the theory of the circulation of the oceans and of flow in open channels [1–4], Wave amplification caused by an energy transfer from turbulent to regular motions, is possible in any medium having space-time fluctuations, provided the correlation time is sufficiently small [5, 6]. As the wave amplitude increases, nonlinear effects become important; they have been taken into account in cases where the interaction of a finite number of harmonics [2, 4] and the structure of steady motions have been examined [3].It is shown in this paper that in a medium with negative viscosity and a second degree dynamic nonlinearity, a solution of the Cauchy problem for an arbitrary “good” form of the initial perturbation, exists over a finite time interval. An example of such a solution is given.     

Quantum effects in an anisotropic ferrimagnet

A model of a two-sublattice collinear ferrimagnet with direct exchange interaction and unequal values of the partial magnetization has been investigated. The condition of existence of the compensation point is determined from material parameters of the system at low temperatures. The excitation spectra are obtained. An analysis is made of the spectra as a function of the total magnetization of the two sublattices.