A number of pulsed experiments have been carried out using a high-voltage circuit containing R,L, and C in certain arrangements. A spherical spark gap of steel electrodes was used as a high-current switch operated by a voltage of up to 8kV and triggered in both self-triggering and third-electrode triggering modes. Current measurements were carried out by using both current-viewing resistor and Rogowski coils designed for this purpose. Typical current waveforms have shown obvious dominating inductance effect of the circuit components in an underdamped oscillation. The behavior of the circuit impedance was studied by recording both pulsed current peaks and the charging voltages when currents of up to 2.5kA were recorded. The duration of these current pulses were found to extend between 0.1?s and 0.3?s depending on the values of the circuit components as well as the spacing of the spark gap electrodes along which the plasma propagates at atmospheric pressure. Over the whole range of experimental conditions, the average nominal impedance values were ranged between (2-10)? depending on the gap and circuit parameters. Typical damage patterns were observed with average diameters of up to 8.3 mm on the high voltage electrode and 10.5 mm on the grounded sphere resulting from accumulative discharges and power dissipation within the gap.
The effects of poles distances of a discharge tube (cathode and anode) were investigated. The distances(90,95,100,110,115,120,130,140)mm are considered. The influence of (25mT) parallel and (2mT) normal magnetic fields with respect to the discharge tube on electron temperature under a pressure of (6pascal) and (900volt) was studied by implementing double Langmuire probe into plasma. Curves fitting were performed to find the optimum values of electron temperature for all cases in this work.We found that the electron temperature as a function of poles distances is exponential form
In this work, plasma parameters such as electron density (ne), electron temperature (Te), Debye length (λD), plasma frequency (fPlasma), and Debye number (ND) for Cu plasma produced by Pin-Plate DC discharge were studied. Spectroscopic technique was used to analyze and determine spectral emission lines. The value of the electron density for Cu was in the range (1.5–3.5)×1018cm-3 and for the electron temperature was in the range ( 1.31 – 1.61)eV. Finally, plasma parameters of Cu were caculated through plasma produced by Pin-Plate DC discharge using different voltages (600-900) V.
In this present paper, an experimental study of some plasma characteristics in dielectric barrier discharge (DBD) system using several variables, such as different frequencies and using two different electrodes metals(aluminium (Al) and copper (Cu)), is represented. The discharge plasma was produced by an AC power supply source of 6 and 7 kHz frequencies for the nitrogen gas spectrum and for two different electrodes metals(Al and Cu). Optical emission spectrometer was used to study plasma properties (such as electron temperature ( ), electron number density ( ), Debye length ( ), and plasma frequency ( )). In addition, images were analysed for the plasma emission intensity at atmospheric air pressure.
Titanium alloy (Ti-6Al-4V) samples were nitrided in low pressure (1.3, 3 mbar) dc-glow discharge plasmas of nitrogen. The treating time was 5, 10 and 15 hour and the temperatures range of the samples during the nitriding process was close to 800oC. The obtained microstructures of the nitride layers were studied by x-ray diffraction and optical microscopy. The ε –Ti2N, ζ-Ti3N3-x and η-Ti3N2-x.phases were formed and addition to the solid solution of nitrogen in titanium, α (Ti,N). Micro hardness measurements exhibit an increment for the Ti-alloy specimens which nitrided at 800oC for 10 and 15h.Corrosion measurements were obtained for the Ti-6Al-4V alloy in Ringer solution after plasma nitriding. The clear improving in the corrosion r
... Show MoreThis study illustrates in vitro effect of cold atmospheric plasma (CAP) on the treatment of Leishmania. In addition, the study evaluated the effect of drug treatment (pentostam) and the combination treatment of pentostan and CAP at different doses and incubation time 24 h in order to assess the most effective treatment. The duration of the cold plasma doses was 1 min, 2 min and 3 min, while the pentostam doses were 2.5 µg/ml and 5 µg/ml. The combinations therapies included combining the three cold plasma doses with the pentostam doses to test 6 combinations of treated in vitro. The maximum growth inhibition was given by combination treated 46% and 44% for donovani and tropica leishamnia respectively; these results give an indi
... Show MoreThe work demonstrates the effect of cold atmospheric plasma (CAP) on adult female rats suffering from osteoporosis, the used plasma was generated by a floating electrode-dielectric barrier discharge system with an electrode diameter of 3 cm. The output power was from (12-20) watts. The effect of non-thermal plasma was observed on rats with various exposure times of 20, 30, and 40 sec. It was noted that the blood calcium percentage of animals exposed to cold plasma increased, as well as an increase in the level of vitamin D3 at the same time, it is noted that there is no effect on parathyroid hormone level. For the thyroid gland, it is noticed an increase in the level of T3, and T4 hormones in the blood during the period of induction for
... Show MoreExperimental results on harmonic distortions in 13.56 MHz RF Argon glow discharge using different grounded electrodes areas and electrodes spacing are presented. The experiment is carried out at four pressure values. RF power values used are between 20 and 90 watts. The results indicate significant increase in distortions at two specific values of the cone angle enclosing the two electrodes within its geometrical volume. The computation of the cone head angle gave the symmetry discharge or asymmetry as well as when the angle is small the condition is near symmetry discharge associated with decrease in the nonlinearity.
The applications of hot plasma are many and numerous applications require high values of the temperature of the electrons within the plasma region. Improving electron temperature values is one of the important processes for using this specification in plasma for being adopted in several modern applications such as nuclear fusion, plating operations and in industrial applications. In this work, theoretical computations were performed to enhance electron temperature under dense homogeneous plasma. The effect of power and duration time of pulsed Nd:YAG laser was studied on the heating of plasmas by inverse bremsstrahlung for several values for the electron density ratio. There results for these ca
... Show MoreDiamond-like carbon, amorphous hydrogenated films forms of carbon, were pretreated from cyclohexane (C6H12) liquid using plasma jet which operates with alternating voltage 7.5kv and frequency 28kHz. The plasma Separates molecules of cyclohexane and Transform it into carbon nanoparticles. The effect of argon flow rate (0.5, 1 and 1.5 L/min) on the optical and chemical bonding properties of the films were investigated. These films were characterized by UV-Visible spectrophotometer, X-ray diffractometer (XRD) Raman spectroscopy and scanning electron microscopy (SEM). The main absorption appears around 296, 299 and 309nm at the three flow rate of argon gas. The value of the optical energy gap is 3.37, 3.55 and 3.68 eV at a different flow rate o
... Show MoreThe magnetic field effect on the current-voltage characteristic curves of glow discharge in argon at low pressures has been experimentally investigated. The electrical discharge was ignited in a stainless steel tapered chamber of a nominal volume of 0.5m3 immersed inside a water-cooled coil capable of delivering a magnetic field of strength B of up to 0.42T. Three water-cooled electrodes were inserted into the chamber up to a point where their tips were 20cm away from the surface of the central column of the chamber. An enhancement of the electric field configuration within the region of the electrode assembly was performed by threading one of the electrodes with stainless circular discs(80mm and 140mm in diameter) in various forms(attac
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