Self-force of a point charge in the space-time of a symmetric wormhole

We consider the self-energy and the self-force for an electrically charged particle at rest in the wormhole space-time. We develop general approach and apply it to two specific profiles of the wormhole throat with singular and with smooth curvature. The self-force for these two profiles is found in manifest form; it is an attractive force. We also find an expression for the self-force in the case of arbitrary symmetric throat profile. Far from the throat the self-force is always attractive.Comment: 18 pages, 3 figures Comments: corrected pdf, enlarged pape

Self-energy and Self-force in the Space-time of a Thick Cosmic String

We calculate the self-energy and self-force for an electrically charged particle at rest in the background of Gott-Hiscock cosmic string space-time. We found the general expression for the self-energy which is expressed in terms of the $S$ matrix of the scattering problem. The self-energy continuously falls down outward from the string's center with maximum at the origin of the string. The self-force is repulsive for an arbitrary position of the particle. It tends to zero in the string's center and also far from the string and it has a maximum value at the string's surface. The plots of the numerical calculations of the self-energy and self-force are shown.Comment: 15 pages, 4 Postscript figures, ReVTe

Electromagnetic field near cosmic string

The retarded Green function of the electromagnetic field in spacetime of a straight thin cosmic string is found. It splits into a geodesic part (corresponding to the propagation along null rays) and to the field scattered on the string. With help of the Green function the electric and magnetic fields of simple sources are constructed. It is shown that these sources are influenced by the cosmic string through a self-interaction with their field. The distant field of static sources is studied and it is found that it has a different multipole structure than in Minkowski spacetime. On the other hand, the string suppresses the electric and magnetic field of distant sources--the field is expelled from regions near the string.Comment: 12 pages, 8 figures (low-resolution figures; for the version with high-resolution figures see http://utf.mff.cuni.cz/~krtous/papers/), v2: two references added, typos correcte

Molecular dynamics of liquid lead near its melting point

The molecular dynamics of liquid lead is simulated at T = 613 K using the following three models of an interparticle interaction potential: the Dzugutov pair potential and two multiparticle potentials (the "glue" potential and the Gupta potential). One of the purposes of this work is to determine the optimal model potential of the interatomic interaction in liquid lead. The calculated structural static and dynamic characteristics are compared with the experimental data on X-ray and neutron scattering. On the whole, all three model potentials adequately reproduce the experimental data. The calculations using the Dzugutov pair potential are found to reproduce the structural properties and dynamics of liquid lead on the nanoscale best of all. The role of a multiparticle contribution to the glue and Gupta potentials is studied, and its effect on the dynamic properties of liquid lead in nanoregions is revealed. In particular, the neglect of this contribution is shown to noticeably decrease the acoustic-mode frequency. © 2009 Pleiades Publishing, Ltd

Experimental: Thermochemical dehydration of oil sludges of different origins

The paper studied the breaking of highly stable oil-water and water-hydrocarbon emulsions of natural and technogenic origin. The main factors are specified which determine the stability and an increased resistance of emulsions to the traditional destruction methods. The effectiveness of thermochemical treatment on various water-oil and water-hydrocarbon emulsions was tested. The demulsifier Rekod-118A was selected as the main reagent used on fields for the destruction of highly stable water-oil emulsions. It was shown that among five provided samples only one sample reduced the content of water to the required standard level after a thermochemical dehydration. It was established that thermochemical dehydration method is generally ineffective for the destruction of highly stable water-oil emulsions and may serve only as the means of preliminary emulsion treatment. It was shown that after thermochemical exposure at 60 °C the water content in IL, HPR, YS emulsions remained at an original level and in MOCW emulsion the water content decreased by 14% and made 19% wt. After the dehydration by thermochemical method, only one sample (LP) out five ones demonstrated the water content reduction to the required standard of performance. Optimum reagent dosage for this raw material made 800 g/t and the process temperature made 60 °C with settling duration of 24 hours

Self-force of a point charge in the space-time of a massive wormhole

We consider the self-potential and the self-force for an electrically charged particle at rest in the massive wormhole space-time. We develop general approach for the renormalization of electromagnetic field of such particle in the static space-times and apply it to the space-time of the wormhole with parameter of the mass, $m$. The self-force is found in manifest form; it is an attractive force. We discus the peculiarities due to massive parameter of the wormhole.Comment: 10 pages, 1 figure text correcte

Universality of microscopic structural and dynamic features in liquid alkali metals near the melting point

© 2017, Pleiades Publishing, Inc. The assumption proposed in [U. Balucani et al., Phys. Rev. B 47, 3011 (1993)] that the space and time dependences of the characteristics of the microscopic structure and dynamics for the group of liquid alkali metals are reduced to a common general form through scaling transformations has been discussed. It has been found that such description is possible when scale units are (i) the effective size of a particle corresponding, in particular, to the experimentally measured position of the main peak in the static structure factor, (ii) the characteristic time scale of the thermal mean free path of the particle, and (iii) the parameters of the “liquidcrystal” phase separation (in particular, the melting temperature). This conclusion follows directly from the comparative analysis of experimental data on X-ray diffraction, as well as on the inelastic neutron and X-ray scattering data. This work develops the ideas proposed in [A. V. Mokshin et al., J. Chem. Phys. 121, 7341 (2004)]

Self-consistent approach in the microdynamics description of supercooled liquids and glasses

A study of the microdynamics of supercooled liquids and glasses is executed through calculations of the dynamic structure factor S(k, θ). The theory developed on the basis of a self-consistent approach in the framework of the memory function formalism is applied to define the frequency spectra (m/k B T)S(k, θ) of supercooled argon at the temperature T = 5 K for the wavenumber region from 2 to 8.5nm-1. The results obtained are in good agreement with the molecular dynamics simulation data. © Pleiades Publishing, Inc., 2006