plasma generator
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Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8486
Author(s):  
Taejoo Oh ◽  
Changseok Cho ◽  
Wookhyun Ahn ◽  
Jong-Gwan Yook ◽  
Jangjae Lee ◽  
...  

In this study, a method was experimentally verified for further reducing the radar cross-section (RCS) of a two-dimensional planar target by using a dielectric rim in a dielectric barrier discharge (DBD) plasma generator using a frequency selective surface (FSS) as an electrode. By designing the frequency selective surface such that the passbands of the radar signal match, it is possible to minimize the effect of the conductor electrode, in order to maximize the RCS reduction effect due to the plasma. By designing the FSS to be independent of the polarization, the effect of RCS reduction can be insensitive to the polarization of the incoming wave. Furthermore, by introducing a dielectric rim between the FSS electrode and the target, an additional RCS reduction effect is achieved. By fabricating the proposed plasma generator, an RCS reduction effect of up to 6.4 dB in X-band was experimentally verified.


2021 ◽  
Vol 189 ◽  
pp. 548-558
Author(s):  
Igor Vavilov ◽  
Konstantin Zharikov ◽  
Viktor Fedyanin ◽  
Pavel Yachmenev ◽  
Anton Lukyanchik ◽  
...  

2021 ◽  
Vol 57 (6) ◽  
pp. 87-107
Author(s):  
I.A. Bosneaga ◽  
◽  
M.C. Bologa ◽  
E.I. Agarval ◽  
◽  
...  

Modern civilization, providing economic and social progress, at the same time objectively creates – sometimes close to ideal – conditions for the spread of various infections. The catastrophic consequences of the SARS-CoV-2 pandemic clearly indicate that homo sapiens appeared to be unable to resist effectively the onslaught of the coronavirus. The purpose of this publication is an attempt to fill the gap in the development of effective methods and means for microbiological decontamination that are optimal in terms of critical parameters. Observational data indicate that a significant number of SARS-CoV-2 coronavirus infections occur by air without a direct contact with the source, including, over a long time interval. Precipitations help to cleanse the air from pollutants and viruses, reducing non-contact contamination, which additionally brings up to date the problem of optimal microbiological decontamination of the air environment and surfaces. A thermodynamic approach has been used to optimize microbiological sterilization. It is shown that irreversible chemical oxidation reactions are the shortest way to achieve sterility, and they are capable of providing high reliability of deconta-mination. It has been established that oxygen is an optimal oxidant, also from the point of view of ecology, since its reactive forms harmoniously fit into natural exchange cycles. The optimal method for obtaining reactive oxygen species for disinfection is the use of low-temperature (“cold”) plasma, which provides energy-efficient generation of oxidative reactive forms – atomic oxygen (O), ozone (O3), hydroxyl radical (·OH), hydrogen peroxide (H2O2), superoxide (O2-), and singlet oxygen O2(a1Δg). Due to a short lifetime for most of the above forms outside the plasma applicator, remote from the plasma generator objects should be sterilized with ozone (O3), the minimum lifetime of which is quite long. It has been substantiated that the microwave method of generating oxygen plasma is optimal for the energy efficient ozone production. A modular principle of generation is proposed for varying the productivity of ozone generating units over a wide range. The module has been developed on the base of an adapted serial microwave oven, in which a non-self-sustaining microwave discharge is maintained thanks to ionizers (igniters), including those based on radiating radionuclides-emitters. In case of massive contamination of surfaces, it is advisable – in addition to ozone (O3) air disinfecting – to use aqueous solutions of hydrogen peroxide (H2O2). It is essential that these reactive oxygen species for disinfecting remote from the plasma generator objects are highly efficient and, at the same time, environmentally neutral. Reliable and affordable personal protective equipment is proposed for activities in zones of increased ozone concentration. The considered optimal means of disinfection can be applicable not only in medicine, but also adapted for numerous practices in agriculture, industry, and in everyday life.


2021 ◽  
Vol 92 (12) ◽  
pp. 125107
Author(s):  
Yasuhisa Sano ◽  
Ken Nishida ◽  
Ryohei Asada ◽  
Shinya Okayama ◽  
Daisetsu Toh ◽  
...  

2021 ◽  
Vol 2064 (1) ◽  
pp. 012029
Author(s):  
I V Lopatin ◽  
Yu H Akhmadeev ◽  
S S Kovalsky ◽  
D Yu Ignatov

Abstract This paper presents the results of a study of an electron-ion-plasma alitization system using two arc plasma generators: a gas plasma generator based on a non-self-sustained arc discharge with a thermionic cathode “PINK” and a gas-metal plasma generator based on an arc discharge with a cathode spot. The system for discharges supplying and biasing of the samples assumes two sub-modes of operation: the ion cleaning sub-mode (ion sub-mode) and the sub-mode of samples electron heating (electron sub-mode), thus realizing the “elion” mode of the system operation. During the experiments, both the dependences of the average values of currents and voltages of discharges burning and probe measurements of the instantaneous plasma parameters values in both system operating sub-modes were investigated. It is shown, that the electron sub-mode of system operation is characterized by an increased burning voltage, which is caused by the formation of a positive anode drop of more than 10 V in the plasmas. Such a potential distribution in the discharges ensures effective heating of the samples by the discharges plasmas electron component.


2021 ◽  
Vol 2100 (1) ◽  
pp. 012008
Author(s):  
S Elliott ◽  
A A Firsov ◽  
S B Leonov

Abstract This work discusses the effect of a filamentary plasma array on shock wave (SW) reflection pattern and on a shock-induced separation zone geometry. It includes experimental and computational components both. The experimentation was performed in the supersonic blowdown test rig SBR-50 at the University of Notre Dame at flow Mach number M=2, stagnation pressure P0=1.7-2.7 bar and stagnation temperature T0=300 K. Oblique shock wave generator composed of a symmetric solid wedge was installed on the top wall of test section while the filamentary plasma generator was arranged on the opposite wall. Thus, the main SW originating from the wedge impinged the plasma area. As a result of the SW-plasma interaction, the flowfield was significantly modified, including a shift of the main SW upstream and redistribution of wall pressure over the test section. The computational analysis allowed a 3D reconstruction of the SW interaction with the plasma array. The physics of SW-plasma array interaction are also discussed.


2021 ◽  
Vol 2100 (1) ◽  
pp. 012006
Author(s):  
A I Klimov ◽  
N K Belov ◽  
V G Brovkin ◽  
A S Pashchina

Abstract Magneto-plasma compressor with a pulsed capillary erosive plasma generator (MPC-EP) has been designed, manufactured and tested at the first time. This MPC-EP was used to study the physical properties of a high-energy long-lived heterogeneous plasma (ELHP) created by pulsed capillary erosive plasma generator (EP) at the wide range of pressure and temperature. The results of measurements of the parameters of the shock wave created by the MPC-EP, as well as optical spectroscopy and soft X-ray spectroscopy are presented.


Plasma ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 399-407
Author(s):  
Dariusz Korzec ◽  
Daniel Neuwirth ◽  
Stefan Nettesheim

The negative air ions (NAI) are used for the removal of particles or droplets from the air. In this study, three types of piezoelectric cold plasma generators (PCPG), in combination with cylindrical electrostatic ion filters, are applied for NAI production. The high voltage on the filter cylinder is induced by the electric field from the piezoelectric transformer of the PCPG. To achieve the dc bias, the cylinder of the electrostatic filter is connected to the ground over ultrafast switching diodes. The ion concentrations are measured for different airflows, PCPG powers, and electrostatic filter geometries. The NAI concentration in the order of magnitude of 107 cm−3, and a negative-to-positive ion concentration ratio of over 200 is reached. The production of ozone is evaluated and the PCPG configuration with a minimum ozone production rate is proposed. The ozone concentration below 60 ppb is reached in the airflow of 90 m3/h.


Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2810
Author(s):  
Ilse Magaña ◽  
Dimitrios Georgouvelas ◽  
Rishab Handa ◽  
María Guadalupe Neira Neira Velázquez ◽  
Héctor Ricardo López López González ◽  
...  

This article proposes a process to prepare fully bio-based elastomer nanocomposites based on polyfarnesene and cellulose nanocrystals (CNC). To improve the compatibility of cellulose with the hydrophobic matrix of polyfarnesene, the surface of CNC was modified via plasma-induced polymerization, at different powers of the plasma generator, using a trans-β-farnesene monomer in the plasma reactor. The characteristic features of plasma surface-modified CNC have been corroborated by spectroscopic (XPS) and microscopic (AFM) analyses. Moreover, the cellulose nanocrystals modified at 150 W have been selected to reinforce polyfarnesene-based nanocomposites, synthesized via an in-situ coordination polymerization using a neodymium-based catalytic system. The effect of the different loading content of nanocrystals on the polymerization behavior, as well as on the rheological aspects, was evaluated. The increase in the storage modulus with the incorporation of superficially modified nanocrystals was demonstrated by rheological measurements and these materials exhibited better properties than those containing pristine cellulose nanocrystals. Moreover, we elucidate that the viscoelastic moduli of the elastomer nanocomposites are aligned with power–law model systems with characteristic relaxation time scales similar to commercial nanocomposites, also implying tunable mechanical properties. In this foreground, our findings have important implications in the development of fully bio-based nanocomposites in close competition with the commercial stock, thereby producing alternatives in favor of sustainable materials.


2021 ◽  
Vol 2021 (8) ◽  
pp. 14-21
Author(s):  
Vladimir Logvin ◽  
Tatyana Karlova

Work purpose: the development of conditions for control automation ensuring tool essential qualities at the stage of finishing with glow discharge plasma. Investigation methods: based on the peculiarities of a human mental process the formation of an electronic model of a neural control system on the basis of engineering process monitoring in industry promoted cybernetic method carrying out for the increase of effectiveness and quality control during the management. The formation of an investigation process for computer technology use at the solution of the problem to ensure specified quality at the realization of engineering processes for metal working tool strengthening in the plasma generator of a glow discharge allowed creating an efficient system of control. The creation of conditions for the fulfillment of human cognitive potentialities with the high degree of similarity such as identification, accumulation and dissemination or transfer of information in the form of electromagnetic pulses similar to neural exchange allows optimizing a control system of quality of product strengthening in the plasma generator of a glow discharge. The formulation of a management solution in the form of the chain of commands in the neural network of the control system of the plasma generator of a glow discharge is formed in accordance with phenomena forming output responses and conditions ensuring their formation. Investigation results: for setting an optimum field of investigations and, accordingly, for increasing effectiveness of the automated control system of finishing quality under the glow discharge plasma impact during the whole engineering process the use of unique potentialities of continuous neural network monitoring is intended. The application of the neural network approach and its unique functions at the formation of the control system using the continuous monitoring of basic engineering process parameters of finishing ensuring specified quality of machining steps realized allows ensuring high repeatability at metal working tool strengthening. In the technological system developed all functions of control and management are based on the use of the neural network approach that allows visualizing its functioning on the monitor in the course of the whole engineering finishing process in the form of graphical dependence. Conclusions: 1. The use of unique potentialities of continuous neural network monitoring allows defining a optimum field of investigations at the lowest cost and accordingly increasing quality of the automated system of finishing quality control at the impact of glow discharge plasma. 2. Depending on material of a tool working part and conditions of tool operation in the surface layer there is formed an essential thermo-dynamic structure with the specified physical-mechanical properties that allows ensuring optimum repeatability. 3. The formation of conditions for the fulfillment with a high degree of similarity human cognitive potentialities such as identification, accumulation and dissemination or transfer of information in the form of electro-magnetic pulses similar to neural exchange allows optimizing a system of quality control of tools strengthened at the stage of glow discharge plasma finishing.


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