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[en] The high voltage dc pulsed glow discharge can be ignited earlier by putting an electron emitting filament in the plasma chamber. The electrons emitted from the filament act as a seed and can cause earlier ignition. The potential of the hot filament shows some periodic positive perturbations (electron loss signals) when it is kept floating in the plasma chamber. It is observed that the positive perturbations disappear as potential difference between the plasma and the filament is made smaller by directly connecting the filament to the grounded chamber
[en] Dielectric barrier discharge (DBD) of Helium and Helium + air modify the surface of Angora rabbit fibers. DBD treatment carried out at different power densities, changes the morphology and chemical composition of the surface of Angora fiber. Scanning electron microscopy (SEM) results reveal that the DBD treatment eliminates fibrosity from the fiber surface. X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer (FTIR) spectrum confirm the increase in oxygen bonding at the surface. These changes reduce shedding of the fibers and improve dye-uptake property. However, even after 10 min of plasma exposure the thermal insulation (heat keeping ratio) of Angora fibers nearly remain unchanged. It has been noticed that DBD treatment (10 min) reduces whiteness of the fiber
[en] The effect of low energy argon plasma treatment on the surfaces of polyethylene terephthalate (PET) was investigated by means of contact angle measurement, X-ray photoelectron spectroscopy (XPS), Vickers’ microhardness indentation and atomic force microscopy (AFM). It was observed that the surface free energy (SFE) changes from 42.1 mJ/m2 to 85.1 mJ/m2 with the increase of plasma treatment time and the corresponding contact angle changes from 60o to 15o. The increase in SFE after plasma treatment is attributed to the functionalization of the polymer surface with hydrophilic groups. The XPS analysis shows the increase in C–O and C=O groups after plasma treatment of the polymer surface. The microhardness of the film increases with the treatment time. This may be attributed to the cross linking effect at the surface. Atomic force microscopy (AFM) reveals that average surface roughness increases from 5.8 nm to 49.7 nm as treatment time increases.