Papers by Keyword: Plasma

Abstract: Polytetrafluoroethylene (PTFE) has many excellent engineering applications for its great properties. We investigated the surface of the PTFE membranes treated with atmospheric pressure low temperature plasma in Ar and Ar/H₂ to confirm the effectiveness for introducing functional groups as surface modifications. From the results of attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopic analysis and X-ray photoelectron spectroscopy (XPS), it was found that the Ar/H₂ plasma was more effective for proceeding defluorination reactions and introducing oxygen moieties compared to Ar plasma under the experimental condition. On the other hand, from the results of scanning electron microscopy (SEM), there were little differences in plasma-treated samples.

Abstract: In order to study surface structures and properties of wool fabric, plasma treatment, grafting and plasma combined grafting treatment are studied in this paper. The structure of samples was characterized by Fourier transform infrared spectroscopy (FTIR). Furthermore, wetting time, grafting ratio and whiteness were also investigated.

Abstract: Meta-aramid fibers were treated by sub-atmospheric pressure dielectric barrier glow discharge plasma. The effect of plasma treatment time on the fiber surface physical and chemical properties was studied by using surface characterization techniques. Scanning electron microscopy (SEM) was performed to determine the surface morphology changes. FT-IR spectroscopy measurements were performed to investigate the change of chemical structure. Dynamic contact angle analysis (DCAA) was used to examine the changes of the fiber surface wettability. SEM analysis showed that there was obvious crack along the fibers’ axial direction present on the fiber surface, which resulted in the better wetting behavior of the plasma-treated PMIA fiber. FT-IR analysis showed that plasma had little effect on the chemical structure of PMIA fibers. DCAA analysis showed that the wettability of the samples could be improved with the treatment time increasing. In addition, a slight decrease in breaking strength was observed at the treatment time ranging from 60 to 180 s in comparison with the untreated sample.

Abstract: This article presents the review and analysis of the literature on methods of utilization of sulphate lignin. It is the product obtained after the processing of cellulose. As a result of the calculations the optimal compositions of the water, organic materials with mechanical impurities with adiabatic combustion temperature about 1200 K to spontaneous combustion were determined. With help of obtained results experimental studies in plasma catalytic reactor were carried out and the also reactor’s operation was optimized. The results can be used to build industrial plants on the basis of plasma catalytic reactor for utilization sulphate lignin.

Abstract: There are shown modeling results of the joint utilization process of tributylphosphate’s spent solutions into hexachlorinebutadiene for uranium and plutonium extraction from nitric acid solution of spent nuclear fuel and its recycling wastes. Utilization process was carried out for widely temperature and mass fraction ranges of air plasma coolant. Also optimal consist of inflammable water-organic compositions and modes for practical application this process in air plasma was determined.

Abstract: Very low pressure plasma spraying has been attracted attention due to special properties of the expanded plasma jet which may probably deposit specific and unique structure coatings, such as columnar structure coatings. The forming of the coatings is affected by plasma generating and working conditions. These operating parameters such as arc power, plasma gas flow rate, and chamber pressure have influences on pressure, enthalpy and temperature of plasma jet. In this work, an enthalpy probe is applied to measure the enthalpy of argon-hydrogen plasma jet generated at chamber pressure of 3000 Pa and 50Pa. The results showed that the temperature of plasma jet reached to 11000 K at 25 mm from nozzle exit, and then dropped slowly to 7000 K at 400 mm.

Abstract: The second harmonic of a pulsed Nd: YAG laser (532 nm) has been used for the ablation of aluminum alloy in air at atmospheric pressure and the laser-induced plasma characteristics are examined in detail. The electron density of 6.7 × 10¹⁷ cm^-3 is inferred from the Stark broadening of the profile of Si (I) 288.16 nm, while the plasma temperature (5982 K) is obtained using the Boltzmann plot method of four neutral aluminum lines. The calibration curve for silicon is established using a set of six samples of standard aluminum alloy, and its limit of detection is 0.0681 wt%. The plasma is verified to be in local thermodynamic equilibrium (LTE) based on the experimental results.

Abstract: This paper investigates the intensity distribution along the radial direction for plasma flow subject to external magnetic Field. The toroidal external magnetism is applied in the transverse direction of plasma flow. Considering the steady-state continuity and momentum of the plasma flow subject to external magnetic field, the intensity profile of the plasma is obtained. The results quantitatively verify the intensity enhancement of the plasma with the increasing external magnetic field.

Abstract: Wave heating is an important way to implement the controlled fusion. The propagation and absorbability of wave in the plasma are described by the two-fluid equations and Maxwell’s equations. A numerical algorithm based on the FDTD method and the MacCormack scheme is designed. The numerical simulation based on parallel computing is carried out to verify the validity of the algorithm and simulation.