Hybrid MHD/PIC simulation of a metallic gas-puff z pinch implosion

We present the hybrid MHD/PIC simulations of the time evolution of a bismuth metallic gas-puff z pinch in external axial magnetic field (AMF). Recent experiments with IMRI-5 generator (450 kA, 450 ns) [1] show the certain effect of an axial magnetic field on radiation energy produced during z pinch implosion. In order to perform the numerical simulation of gas puff z pinch a hybrid model was developed. The hybrid model treats the electrons as a massless fluid and ions as macroparticles. The macroparticle dynamic is calculated with the use of PIC method. Ion-ion Coulomb collision is considered with the use of MC method. The radiation transfer of bismuth plasma was accounted in the framework of P1 method. The interelectrode gap pumping by plasma of 8 μs 80 kA bismuth arc with the following plasma implosion by 450 kA / 450 ns current pulse in different external AMF was modelled. The obtained results are in a reasonable agreement with the experimental results. © Published under licence by IOP Publishing Ltd.The work was supported by Russian Science Foundation (project No. 16-19-10142)

On Hybrid Type of Cathode Attachment in High Current Vacuum Arcs

This paper discusses the issues of a possible change of the type of cathode attachment of high-current vacuum arcs (HCVA) with an average cathode current density of more than 105 A/cm2. This type of HCVA is used as pumping plasma gun in experiments with plasma puff z-pinches. These experiments showed that the measured linear mass of the HCVA plasma jet is much higher (by a factor of 10 or more) than the expected mass, which can be obtained from the assumption that cathode attachment occurs only through a multitude of cathode spots emitting supersonic plasma jets. It is shown that in HCVA of the type under consideration, at some time instant there are two types of cathode attachments - cathode spots and thermionic erosion attachment (TEA). It can be said that HCVA of this type have a hybrid cathodic attachment. Unlike cathode spots, TEA produces a subsonic plasma flow, which contributes to an increase in the linear mass of the HCVA plasma jet. © 2021 Institute of Physics Publishing. All rights reserved

Withdrawal of inhaled corticosteroids in COPD patients: rationale and algorithms

COPD; Treatment algorithm; Guideline adherenceEPOC; Algoritmo de tratamiento; Adherencia a la guía clínicaMPOC; Algoritme de tractament; Adherència a la guia clínicaObservational studies indicate that overutilization of inhaled corticosteroids (ICS) is common in patients with chronic obstructive pulmonary disease (COPD). Overprescription and the high risk of serious ICS-related adverse events make withdrawal of this treatment necessary in patients for whom the treatment-related risks outweigh the expected benefits. Elaboration of an optimal, universal, user-friendly algorithm for withdrawal of ICS therapy has been identified as an important clinical need. This article reviews the available evidence on the efficacy, risks, and indications of ICS in COPD, as well as the benefits of ICS treatment withdrawal in patients for whom its use is not recommended by current guidelines. After discussing proposed approaches to ICS withdrawal published by professional associations and individual authors, we present a new algorithm developed by consensus of an international group of experts in the field of COPD. This relatively simple algorithm is based on consideration and integrated assessment of the most relevant factors (markers) influencing decision-making, such a history of exacerbations, peripheral blood eosinophil count, presence of infection, and risk of community-acquired pneumonia

Formation of double shell during implosion of plasma metal puff Z-pinches

This work presents the results of experimental and theoretical research of impact of tailored density profile and application of external axial magnetic field on initial spatial distribution of the plasma density in the plasma metal puff Z-pinch and on its implosion dynamics. It has been discovered that upon implosion of the plasma metal puff Z-pinch some stripes interpreted as the system of two coaxial shells appear on the optical images. With the help of numerical simulation, the formation of the plasma liner consisting of a mixture of carbon and bismuth ions and formed by the expansion of the plasma jet of the arc burning on the bismuth electrode has been considered in this work. It has been shown that the lightweight carbon ions facilitate formation of the density distribution smoothly decreasing with the increase in radius, that, in turn, leads to suppression of the Rayleigh-Taylor instability in the current sheath upon further implosion. It has also been demonstrated that availability of the two types of ions in plasma considerably different in mass leads to formation (in the compression phase) of a double shell with externally located heavy ions. It has also been revealed that the application of the external axial magnetic field leads to reduction in the plasma metal puff Z-pinch initial diameter. © 2020 Author(s).This work was funded by Russian Science Foundation. Project No. 19–19-00127

ВЛИЯНИЕ МИГРАЦИОННЫХ ПРОЦЕССОВ НА МУСУЛЬМАНСКОЕ СООБЩЕСТВО РОССИИ

The impact of the migration processes on the Islamic community of Russia is considered in the article. The classification of the reasons for the Muslim migration in Russia is given. The authors pay the primordial attention to the up-todate situation; concentrate on the peculiarities of the influence of Muslim migrants on the Islamic community of Russia, the possible reasons for the conflicts and ways of their resolution. Besides, the perspectives of the dialogue between the original population and the Muslim migrants are analyzed as well.В данной статье рассмотрено влияние миграционных процессов на исламское сообщество России. Приводится классификация по целям приезда мигрантов в Россию. Уделяется особое внимание описанию современной ситуации, авторы раскрывают особенности влияния мусульманских мигрантов на мусульманское сообщество России, возможные причины конфликтов. Кроме того, предлагаются пути решения конфликтных ситуаций. Рассмотрены перспективы диалога между коренным населением и мигрантами из мусульманских стран

A transverse current rectification in graphene superlattice

A model for energy spectrum of superlattice on the base of graphene placed on the striped dielectric substrate is proposed. A direct current component which appears in that structure perpendicularly to pulling electric field under the influence of elliptically polarized electromagnetic wave was derived. A transverse current density dependence on pulling field magnitude and on magnitude of component of elliptically polarized wave directed along the axis of a superlattice is analyzed.Comment: 12 pages, 6 figure

On possible reasons of positive near-anode voltage drop in high-current vacuum arc

In this paper we consider some reasons for the occurrence of a positive near-anode potential drop during current constriction in high-current vacuum arc. It is shown that if the radius of constriction is much larger than the electron mean free path, then a positive voltage drop in the near-anode plasma sheath does not occur, but an additional drop may occur in the near-anode plasma layer due to the anomalous resistance. If the current constriction radius is much less than the electron mean free path, then a positive voltage drop in the sheath arises under the usual condition, and the kinetic instabilities in the near-anode plasma do not develop. © 2019 IOP Publishing Ltd. All rights reserved.Russian Foundation for Basic Research, RFBR: 17-02-00346, 18-08-00547Russian Academy of Sciences, RASNational Natural Science Foundation of China, NSFC: 5191153011318-2-2-16This work was supported in part by RFBR(grant Nos. 17-02-00346, 18-08-00547, 19-08-00783, 19-58-53006), by RAS Program (project No. 11) and UB RAS Program (project No. 18-2-2-16), as well as by National Natural Science Foundation of China (project No. 51911530113)

VIRTUAL REALITY FOR MANAGEMENT OF SITUATIONAL AWARENESS DURING GLOBAL MASS GATHERINGS

This paper presents a training technology for staff of mass events for development of action skills in large gatherings of people, including crowd dynamic management and actions in extreme situations caused by the panic. The technology is based on the multi-agent model of crowd dynamic with dynamically re-computable navigation fields. We implemented the software system that provides a collaborative and distributed process of training activities in the virtual reality environment. The following characteristics of the developed software system available from experimental studies were analyzed: computational intensity of simulations, scalability of rendering system and reactivity of the final system when rendering computationally intensive scenes. The proposed models and infrastructure for training through collaborative immersion in the virtual reality can improve situational awareness of events staff prior to the event. The developed technology is a unique tool for improving the quality and safety of disposable and unique events involving the broad masses of people, including unfunded by retrospective experience mass gatherings. Developed technology was tested within the Kumbh Mela festival in Ujjain, India