Search

In this work, the effectiveness of atmospheric pressure non-equilibrium plasma, generated by a dielectric barrier discharge and operated in air, in successfully crosslinking water soluble pullulan electrospun fibers is demonstrated. After being exposed to plasma, the fibers show a remarkable capability to preserve structural stability and fiber morphology upon water exposure. The gel fraction and the water absorption are quantified to evaluate the crosslinking efficiency of different plasma operating conditions, and ATR-FTIR characterization provided some insights into plasma-induced modification of pullulan chemical structure. [ABSTRACT FROM AUTHOR]

Abstract: Atmospheric microwave air plasma was used to treat asbestos-like microfiber particles that had two types of ceramic fiber and one type of stainless fiber. The treated particles were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experiment results showed that one type of ceramic fiber (Alumina:Silica=1:1) and the stainless fiber were spheroidized, but the other type of ceramic fiber (Alumina:Silica=7:3) was not. The conversion of the fibers was investigated by calculating the equivalent diameter, the aspect ratio, and the fiber content ratio. The fiber content ratio in various conditions showed values near zero. The relationship between the normalized fiber vanishing rate and the energy needed to melt the particles completely per unit surface area of projected particles, which is defined as η, was examined and seen to indicate that the normalized fiber vanishing rate decreased rapidly with the increase in η. Finally, some preliminary experiments for pure asbestos were conducted, and the analysis via XRD and phase-contrast microscopy (PCM) showed the availability of the plasma treatment. [Copyright &y& Elsevier]

Abstract: This paper reports the synthesis of ammonia from nitrogen and hydrogen as a model reaction in atmospheric microwave plasma. From the obtained results, we then investigate the effects of hydrogen addition to a plasma gas and hydrogen injection into the afterglow region of the plasma on ammonia production. The results showed that the addition of hydrogen to a plasma gas depressed nitrogen activation in the plasma. Hydrogen injection into the afterglow region of the plasma enhanced ammonia production. Dilution of a plasma gas with argon was effective for promoting the formation of active nitrogen species, resulting in the enhancement of ammonia production. The results suggest that active nitrogen species played a key role in ammonia production using atmospheric microwave plasma. [Copyright &y& Elsevier]