This paper reports the results of electrical characterization of aluminum thin films. Uniform Al thin films were deposited by physical vapor deposition (PVD) technique on glass substrates. The electrical resistivity of the films as a function of film thickness was studied. These parameters have been measured by four-point probe method. The electrical resistivity was obtained by the measurement of current (in mA) and voltage in (mV) through the probe. The results showed that resistivity of the film decreases linearly with the film thickness in the range of the thickness studied in this work. Kathmandu University Journal of Science, Engineering and Technology Vol. 8, No. II, December, 2012, 31-36 DOI: http://dx.doi.org/10.3126/kuset.v8i2.7322

Seed germination is a complicated physiological process that starts with the seed absorbing water and concludes with the radicle emerging. The kinetics and amount of water uptake by seeds are known to be influenced by both seed surface properties and the surrounding environment. As a result, altering seed surface features are linked to seed medium and is a valuable strategy for controlling seed germination. In the agricultural field, non-thermal plasma surface activation of seeds is currently being investigated as an efficient pre-sowing treatment for modifying seed germination. The impact of non-thermal plasma (NTP) on the germination and seedling growth of carrot seeds at room temperature and atmospheric pressure for varied treatment times was investigated in this study. Seed's germination properties and growth parameters were examined for both control and NTP treated seeds. Germination-related parameters such as germination percentage, vigor index, and chlorophyll content were all improved by NTP treatment. However, no significant changes were seen in the carotenoid content. Similarly, the in-vitro radical scavenging activities, total phenol, and total flavonoid contents in the seedlings were altered by NTP treatment. Our results indicate that NTP treatment has a favorable effect on carrots germination and seedling development.

In this study, an atmospheric alternating-current gliding arc device using line frequency (50 Hz) has been designed for the generation of various reactive species in different working gases. Electrical characteristics of the generated discharge are investigated by oscilloscope while the optical characteristics are analyzed using optical emission spectroscopy. The role of different working gases (oxygen, argon and air) on discharge voltages and power consumption per cycle in the discharge are calculated and compared. Electron density and electron temperature of the discharge are estimated by electrical and optical method respectively. The production of reactive species in the discharge is affirmed by optical emission spectroscopy. The outcomes of the results confirm that the GAD can generate non-equilibrium plasma having reactive nitrogen and oxygen species (RONS) which are essential for plasma chemistry applications.

Cold plasma-liquid interaction becomes a growing interdisciplinary area of research involving plasma physics, fluid science, and chemistry. Plasma-liquid interaction has gained more interest over the last many years due to its potential applications in different fields. Cold atmospheric plasma jet is an emerging technology for surface drinking water treatment to improve quality and surface modification that is chemical-free and eco-friendly. Cold plasma treatment of water samples results in changes in turbidity, pH, and conductivity and in the formation of reactive oxygen and nitrogen species (RONS). As a result, plasma-activated water has a different chemical composition than water and can serve as an alternative technique for microbial disinfection. CAPJ has been generated by a high voltage 5 kV and a high frequency 19.56 kHz power supply. The discharge has been characterized by an optical method. To characterize the cold atmospheric pressure argon plasma jet, discharge plume temperature, and electron rotational and vibrational temperature have been determined. Cold atmospheric argon plasma jet produced at atmospheric condition contains high energetic electrons, ions, UV radiation, reactive oxygen, and nitrogen species named as cold plasma which has a wide range of applications in the biomedical industry, as well as in water treatment. Nowadays, researches have been carried out on ozonation through plasma jet interaction with surface drinking water. In this paper, we compare the change in physical and chemical parameters of surface water used for drinking purposes. The significant change in the physical parameters such as pH, turbidity, and electrical conductivity was studied. In addition, the significant changes in the concentration and absorbance of nitrate, ferrous, and chromium ions with respect to treatment time were studied. Our results showed that plasma jet interaction with surface drinking water samples can be useful for the improvement of water quality and an indicator for which reactive species play an important role in plasma sterilization.

In this research work, co-axial cylindrical dielectric barrier discharge (CCDBD) system has been used as a ozone generator for ozone production with air as a working gas. The breakdown of air was generated inside the reactor by using low line frequency of 50 Hz and high AC voltage power supply system. The variation of air flow rate (Q) was taken from 10 to 16 l/min in this experiment. The O3 concentration denoted by C(O3) decreases with increasing the rate of flow of air at fixed discharge time and applied voltage. When discharge time (t) increases, C(O3) increases at fixed applied voltage. C(O3) also increases with increasing applied voltage (V) for constant discharge time. If the gap space between the electrodes increases then C(O3) increases. We have used glass tube reactor for this work having internal diameter of 18 mm and copper, brass and iron electrodes of diameter 8 mm. It was estimated that C(O3) found higher for copper electrode than both brass and iron electrode for certain discharge time, applied voltage and reactor diameter.