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This paper aims at building a discharge model for the power cable bellows based on plasma energy deposition and analyzing the discharge ablation problem.

Aiming at the multiphysical mechanism of the discharge ablation process, a multiphysical field model based on plasma energy deposition is established to analyze the discharge characteristics of the power cable bellows. The electrostatic field, plasma characteristics, energy deposition and temperature field are analyzed. The discharge experiment is also carried out for result validation.

The physical mechanism of the bellows ablative effect caused by partial discharge is studied. The results show that the electric field intensity between the aluminum sheath and the buffer layer easily exceeds the pressure resistance value of air breakdown. On the plasma surface of the buffer layer, the electron density is about 4 × 1,019/m³, and the average temperature of electrons is about 3.5 eV. The energy deposition analysis using the Monte Carlo method shows that the electron range in the plasma is very short. The release will complete within 10 nm, and it only takes 0.1 s to increase the maximum temperature of the buffer layer to more than 1,000 K, thus causing various thermal effects.

Its physical process involves the distortion of electric field, formation of plasma, energy deposition of electrons, and abrupt change of temperature field.

The purpose of this paper is to describe experimental and numerical investigations focussed on the shock wave modification induced by a dc glow discharge. The model is a flat plate in a rarefied Mach 2 air flow, equipped with a plasma actuator composed of two electrodes. The natural flow without actuation exhibits a shock wave with a hyperbolic shape. When the discharge is on, the shock wave shape remains hyperbolic but the shock wave is pushed forward, leading to an increase in the shock wave angle. In order to discriminate thermal effects from purely plasma ones, the plasma actuator is then replaced by an heating element.

The experimental study is carried out with the super/hypersonic wind tunnel MARHy located at the ICARE Laboratory in Orléans. The experimental configuration with the heating element is simulated with a code using the 2D full compressible Navier-Stokes equations adapted for the rarefied conditions.

For heating element temperatures equal to the flat plate wall surface ones with the discharge on, experimental and numerical investigations showed that the shock wave angle was lower with the heating element, only 50 percent of the values got with the plasma actuator, meaning that purely plasma effects must also be considered to fully explain the flow modifications observed. The results obtained with the numerical simulations are then used to calculate the aerodynamic forces, i.e. the drag and the lift. These numerical results are then extrapolated to the plasma actuator case and it was found that the drag coefficient rises up to 13 percent when the plasma actuator is used, compared to only 5 percent with the heating element.

This paper matters in the topic of atmospheric entries where flow control, heat management and aerodynamic forces are of huge importance.

The paper describes the plasma polymerisation process for depositing ultrathin films. Such films, deposited from monomers containing hydrophobic elements such as hexafluorobenzene and hexamethyldisiloxane, showed excellent water vapour barrier properties, due to dense, highly crosslinked and rigid structures of the films. The composition and structure of the plasma polymerised films have been elucidated by ESCA and infra‐red spectroscopy.

This paper aims to study the breakdown, oscillation and vanishing of the discharge channel and its influence on crater formation with simulation and experimental methods. The experiment results verified the effect of the oscillating characteristics of the discharge channel on the shape of the crater.

A mathematical model that considers the magnetohydrodynamics (MHD) and the discharge channel oscillation was established. The micro process of discharging based on magnetic-fluid coupling during electrical discharge machining (EDM) was simulated. The breakdown, oscillation and vanishing stage of the discharge channel were analyzed, and the crater after machining was obtained. Finally, a single-pulse discharge experiment during EDM was conducted to verify the simulation model.

During the breakdown of the discharge channel, the electrons move towards the center of the discharge channel. The electrons at the end diverge due to the action of water resistance, making the discharge channel appear wide at both ends and narrow in the middle, showing the pinch effect. Due to the mutual attraction of electrons and positive ions in the channel, the transverse oscillation of the discharge channel is shown on the micro level. Therefore, the position of the discharge point on the workpiece changes. The longitudinal oscillation in the discharge channel causes the molten pool on the workpiece to be ejected due to the changing pressure. The experimental results show that the shape of the crater is similar to that in the simulation, which verifies the correctness of the simulation results and also proves that the crater generated by the single pulse discharge is essentially the result of the interaction between transverse wave and longitudinal wave.

In this paper, the simulation of the discharge breakdown process in EDM was carried out, and a new mathematical model that considers the MHD and the discharge channel oscillation was established. Based on the MHD module, the discharge breakdown, oscillation and vanishing stages were simulated, and the velocity field and pressure field in the discharge area were obtained.

The purpose of this paper is to develop and characterize a pulsed plasma thruster (PPT) that does not need a spark plug to initiate the plasma discharge.

Two parallel rail thrusters were built and their performances were characterized inside a vacuum chamber to elucidate the effect of vacuum level and thruster geometry on the performance. The thruster electrical performance was quantified by measuring the voltage output from a Rogowski coil connected to the power supply. The thrust produced by the developed thruster was estimated by measuring the force exerted by the plume on a light weight pendulum, whose deflection was measured using a laser displacement sensor.

The thruster can operate without a spark plug. In general, the performance parameters such as thrust, mass ablation, impulse bit, and specific impulse per discharge, would increase with increasing pressure levels up to an optimum level due to the increase in discharge energy as well as the decrease in the total impedance of the plasma discharge. The discharge frequency is function of the breakdown potential, the total resistance in the equivalent circuit, and the capacitance of the circuit. The total impedance of the circuit decreases with pressure level and hence the discharge energy increases. The thrust efficiency is found to be affected by the thruster geometry as well as the discharge energy.

The studies reported in this paper have been carried out at relatively higher pressure levels compared than prevail in space. However, it should be possible to extrapolate these results to the lower vacuum levels at which the performance is independent of the geometry.

The results reported in this paper suggest a design guideline for auto‐initiated PPT.

If the spark plug is eliminated, the size of the thrusters can be reduced and arrays of such thrusters can be manufactured using micro electro mechanical systems techniques, which can provide tremendous control authority over the satellite positioning.

This paper aims to synthesize silver nanoparticles using atmospheric discharge plasma in contact with liquid at different pressure in reactor and to assess their catalytical properties for reducing 4-nanoparticles (NP).

The Ag colloidal NPs was rapidly synthesized as a result of non-equilibrium low-temperature plasma formation between an electrode and the surface of AgNO₃ solution for 5 min at different pressure in reactor. Synthesized Ag NPs were characterized with common analytical techniques. Ultraviolet–visible (UV) spectroscopy, dynamic light scattering, scanning microcopy analysis were used to study the formation and characteristics of silver nanoparticles.

The formation of silver colloidal solutions under plasma discharge at different pressure in reactor is characterized by the presence of surface resonance peak in the spectra. Scanning electron microscope (SEM) images confirmed the formation of spherical particles having a size distribution in the range of 15-26 nm. The AgNPs solution showed excellent rapid catalytic activity for the complete degradation of toxic 4-nitrophenol (4-NPh) into non-toxic 4-aminophenol (4-APh) within 18 min.

Further studies are necessary for confirmation of the practical application, especially of deposition Ag NPs on TiO₂.

The method provides a simple and practical solution to improving the synthesis of colloidal solutions of Ag NPs for degradation of organic pollutants (4-NPh) in water and wasters water.

Atmospheric discharge plasma in contact with liquid at different pressure can be used as an effective technique for synthesis of nanomaterials with catalytic properties.

This paper aims to investigate the effects of a dielectric barrier discharge (DBD) plasma actuator (PA) qualitatively on aerodynamic characteristics of a 3 D-printed NACA 4412 airfoil model.

Airflow visualization study was performed at a Reynolds number of 35,000 in a small-scale open-loop wind tunnel. The effect of plasma actuation on flow separation was compared for the DBD PA with four different electrode configurations at 10°, 20° and 30° angles of attack.

Plasma activation may delay the onset of flow separation up to 6° and decreases the boundary layer thickness. The effects of plasma diminish as the angle of attack increases. Streamwise electrode configuration, in which electric wind is produced in a direction perpendicular to the freestream, is more effective in the reattachment of the airflow compared to the spanwise electrode configuration, in which the electric wind and the free stream are in the same direction.

The Reynolds number is much smaller than that in cruise aircraft conditions; however, the results are promising for low-velocity subsonic airflows such as improving control capabilities of unmanned aerial vehicles.

Superior efficacy of spanwise-generated electric wind over streamwise-generated one is demonstrated at a very low Reynolds number. The results in the plasma aerodynamics literature can be reproduced using ultra-low-cost off-the-shelf components. This is important because high voltage power amplifiers that are frequently encountered in the literature may be prohibitively expensive especially for resource-limited university aerodynamics laboratories.

The purpose of this paper is to focus on the influence of electromagnetic field during the arc discharge carbon nanotubes synthesis. It proposes modeling of electromagnetic field distribution to calculate forces in the area of arcing. The paper presents the influence of this field on the final product of the synthesis.

A short literature review of the arc discharge systems supported by electromagnetic field is presented. The technical solution of the coil placement is discussed. An experimental research is described. The research system constructed preceded by a series of measurements and modeling is analyzed.

The paper describes the significant meaning of the electromagnetic field during the synthesis. The electromagnetic field forces the slow rotation of the carbon plasma column where carbon nanotubes are formed. It leads to the improvement in yield.

Because the research is limited to one type of geometry of the reactor, the results may vary in different reactors. However, the influence of the electromagnetic field is confirmed. Therefore, researchers are encouraged to investigate the influence of the electromagnetic coil in the applied systems.

The systems with a coil inside the reactor require the application of complex cooling systems or/and additional screens. The work proposes a technical solution based on the coil placed outside the reactor. Therefore, it simplifies the construction and increases the yield.

The high yield of the high-quality nanotubes opens new technical possibilities for electronics and electrical engineering.

The paper identifies a connection between the electromagnetic field, the arc discharge movement, plasma jet, carbon nanotubes containing deposit and the yield.

This paper aims at examining the potentiality of using Hibiscus sabdariffa L. calyces’ (Hs) aqueous extract to remove soot stains from the surface of fire-damaged silver gelatin prints. It further studies the cleaning efficiency and impact of both a contact method and a noncontact method with argon dielectric barrier discharge plasma (DBD Ar. plasma) on the different properties of silver gelatin prints. Accordingly, it prompts using economic, eco-friendly materials and methods in the photograph conservation field.

To achieve the aims of this paper, four silver gelatin prints were stained with soot and treated with the Hs aqueous extract as a contact method and DBD Ar. plasma combined with the aqueous extract as a noncontact method. The assessment was carried out using digital microscopy, atomic force microscopy and spectrophotometer to study the efficiency of the tested treatments and their impact on the surface of the photographs. Fourier transform infrared was used to monitor the state of the binder after cleaning. Furthermore, the pH and the mechanical properties were measured.

The contact method resulted in lower concentrations of Hs extract that efficiently cleaned the surface without causing any stains or damage to the treated photographs. The noncontact method (plasma with an aqueous extract) proved to be less effective in cleaning and made the binder more susceptible to deterioration.

This paper reveals the success of Hs aqueous extract in cleaning soot on vulnerable photographs' surfaces.

This paper aims to propose a simple, eco-friendly method for obtaining colloidal solutions of silver nanoparticles (Ag NPs) by using of contact non-equilibrium low-temperature plasma in presents polysorbate-80 and to assess their antibacterial activity in composite materials (beads) for water treatment process.

Silver nanoparticles were prepared in aqueous AgNO3 solution by using of contact non-equilibrium low-temperature plasma in the present of nonionic surfactant polysorbate-80 (Tween 80) as capping agent. Ultraviolet–visible (UV) spectroscopy, X-ray diffraction and zeta potential analysis were used to study the formation and properties of silver nanoparticles.

The formation of silver colloidal solutions in the presence of capping agent under plasma discharge is characterized by the presence of peak λmax = 380 – 402 nm in the spectra. The addition of sodium alginate into the reaction mixture allows synthesizing stable colloidal silver solutions. The average size of formed silver particles is up to 50 nm. Ag NPs exhibited an excellent bactericidal activity against both gram-positive and gram- negative bacteria. Composite beads prepared using nonionic surfactant were found to be effective in disinfecting the Staphylococcus aureus to different extents.

Further studies are necessary for confirmation of the practical application, especially of the toxicity of Ag NPs, as well as the sorption properties of the alginate beads with Ag NPs.

The method provides a simple and practical solution to improving the synthesis of colloidal solutions of Ag NPs for water treatment process.

Contact nonequilibrium low-temperature plasma can be used as an effective technique for synthesis of nanomaterials.