In this research, a type of gram negative bacteria was exposed to non-thermal plasma at a distance of (2 and 3 cm) from the plasma flow nozzle, with the use of an alternating power supply (5KHz), where exposure was made at two different voltages (4.9 and 8 kV). A negative gram of Pseudomonas aeruginosa bacteria was isolated and exposed to non-thermal plasma at different flow rates of argon gas whose value ranged from (1-5) liters/minute. The results showed that bacterial killing rate is directly proportional to distance while exposing the samples to non-thermal plasma, and the best factors by which a complete killing rate was obtained were at a distance of 2 cm with a voltage of 8 kV and a gas flow rate of 5 liters/min, while complete killing of bacteria was not achieved at a distance of 3 cm where the percentage was 95% at the same argon gas flow rate.
In this paper, spectroscopic analysis (OES) for copper (Cu) plasma was achieved at atmospheric pressure. Q switched Nd: YAG pulsed laser with a fundamental wavelength (1064 nm), energy range (500-800) mJ, frequency (6 Hz), and laser pulses (10-30 pulses) was applied to induce copper plasma. Based on the spectroscopic analysis, plasma parameters like electron temperature (Te), electron density (ne), Debye length (λD), and plasma frequency (fp) have been calculated. The results demonstrated that the laser energy affects all plasma parameters, with an electron temperature (Te) range of (0.6820-0.8949) eV and electron number density (ne) range of (13.667-17.235)×1017 cm−3. Also, the image of the place of laser bombardment of copper (Cu) metal shows three diameters or circles, each circle bears a different color from the other. It can be described as a crater, and the interaction of the laser with copper metal is obvious by laser ablation, and here the effect of the increased energy of the laser appears during the spectroscopic diagnosis and the process of metal bombardment.
In this paper, ZnO NPs were prepared using D.C high-voltage and high frequency with an output of 6 kHz at two different preparation times preparation (10,12) minutes. Transmission electron microscopy (TEM) with (FE-SEM) was used to examine the homogenous, compact, and dense surface of the zinc oxide nanoparticles created with apparent grain size determined by (XRD), XRD results explain that the increase of the preparation time from 10 minutes to 12-minute caused an increase in crystallite size. In addition, FE-SEM showed that the increase in the ZnO NPs cluster distribution with particle size increases with increasing the preparation time. AFM was also utilized to determine the degree of cooperation between the surfaces of the zinc oxide nanoparticles, with having a high degree of stability by zeta potential -13.3±1.8mV at 12 minutes.
In this work, plasma system that operates at vacuum was designed and built using a sheet of cobalt metal for the purpose of diagnosing plasma and measuring its parameters, as it is very important to know the processes that accompany plasma generation and are closely related to them, including the electron density in the plasma and its temperature. The spectroscopic diagnosis was done by optical emission spectroscopy (OES) which relies on the calculation of the optical radiation emitted by the plasma to describe plasma parameters in the chemical, molecular, and ionic radiator's near environment, and applied to cobalt metal at vacuum D.C high voltage power supply. The results showed the rise of spectral lines intensity with increasing the applied voltage. The maximum peak of argon gas (ArI) was at the wavelength (811.5311) nm and the maximum peak of cobalt metal (CoI) was at the wavelength of 242 nm, where argon gas was used at the fifth flow per minute with variable voltages (13-21) kV. The results also achieved that the values of electron temperature rises from (0.2708-0.6649) eV with the increase in the applied voltage, as well as the electron density from (8.108-13.851)x1017cm-3 with the stability of the argon gas flow rate at 5 l/min. The length of the plasma was measured at different gas flow rates (1-5) l/min and different applied voltages (13-21) kV that were used in this diagnosis.
In this research, the non-thermal plasma system is designed with diameter (10 mm) Argon at atmospheric pressure as well as to be suitable for use in medical and biotechnological applications. The electric description of this system was studied. In this paper, a non-pure argon gas plasma system is designed and manufactured that operates at pressure The normal air. Where the electrical description of this system was studied through the use of values Different voltages and different values of how quickly the argon flows. As the results obtained showed the small value of the electric current consumed by the needle system Non-thermal plasma, where it was in the range of several microns of amps, and the value of the electric current increased with the increase in the gas flow, and the results also showed a breakdown of voltages when the voltage used was 5 kilovolts, which caused a slight decrease in the value of the electric current when the gas flow was 4 liters The minute.
A LIBS technique was used to investigate the antibacterial activity of calcium oxide nanoparticles (CaO NPs). CaO NPs were prepared using a Q-switched Nd: YAG pulsed laser with a fundamental wavelength of 1064 nm at different energies (400-600 mJ) and constant frequency (6 Hz). A calcium powder sample was prepared after being pressed into a disc with a diameter of 1 cm. Analyzing X-ray diffraction (XRD) showed the crystalline structure of CaO NPs, crystalline size was 30.99±2 and 34.20±2.2 nm for laser energy 500 and 600 mJ. (FE-SEM) to reveal the topography of produced CaO NPs, the results showed a homogenous compact and dense surface with the formation of CaO NPs like flakes, cubes, and tubes. Atomic force microscopy (AFM) has shown that the CaO NPs were nanoscale and had a coordinated surface structures. The results also revealed the stabilizing zeta potential of the prepared CaO NPs, average (ZP) -18.3±1.6 mV in 600 mJ and -8.8±2.3 mV for 500 mJ. Different laser energies used in preparing CaO NPs resulted in the varying killing of the number of bacteria Klebsiella pneumoniae and Staphylococcus aureus bacteria. Complete bacterial inhibition or cell growth inactivation was found when the laser energy prepared for the CaO NPs was 600 mJ.
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