Axial light emission and Ar metastable densities in a parallel plate dc micro discharge in steady state and transient regimes

Axial emission profiles in a parallel plate dc micro discharge (feedgas: argon; discharge gap d=1mm; pressure p=10Torr) were studied by means of time resolved imaging with a fast ICCD camera. Additionally, volt-ampere (V-A) characteristics were recorded and Ar* metastable densities were measured by tunable diode laser absorption spectroscopy (TDLAS). Axial emission profiles in the steady state regime are similar to corresponding profiles in standard size discharges (d=1cm, p=1Torr). For some discharge conditions relaxation oscillations are present when the micro discharge switches periodically between low current Townsend-like mode and normal glow. At the same time the axial emission profile shows transient behavior, starting with peak distribution at the anode, which gradually moves towards the cathode during the normal glow. The development of argon metastable densities highly correlates with the oscillating discharge current. Gas temperatures in the low current Townsend-like mode (T= 320-400K) and the high current glow mode (T=469-526K) were determined by the broadening of the recorded spectral profiles as a function of the discharge current.Comment: submitted to Plasma Sources Sci. Techno

Fatty acid composition of maize germ oil from high-oil hybrids wet-milling processing

Maize germ was obtained by wet-milling laboratory processing of domestic high-oil maize hybrids. After separation, the germ was subjected to extraction of maize oil. Fatty acid composition of maize germ oil was determined by gas chromatography. The results showed very high levels of unsaturated fatty acids and a constant sum of oleic and linoleic acids in oils of different maize hybrids

Oscillation modes of dc microdischarges with parallel-plate geometry

Two different oscillation modes in microdischarge with parallel-plate geometry has been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier Transform Spectra of relaxation oscillations reveal chaotic behaviour of microdischarge. Volt-Ampere characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge and normal glow. However, free-running oscillations appear in subnormal glow only.Comment: Submitted to: New Journal of Physic

Spatiotemporal profile of emission from oscillating dc micro discharges

The axial light distributions in parallel-plate dc microdischarges in argon show similar behavior to large scale discharges. Between the low-current Townsend mode and the high current glow mode exists a large region of currents where different oscillations appear and the dynamic Volt-Ampere characteristic shows hysteresis behavior. During the oscillations the maximum peak intensity moves closer to the cathode, which is characteristic for the abnormal glow regime even though the average current is considerably smaller.Comment: submitted to: IEEE Trans. Plasma Sci., Spec. Issue on Images in Plasma Sc

Planovi i programi fizičkog vaspitanja u procesu obuke u JNA u periodu od 1951. do 1992. godine

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A Monte Carlo simulation of ion transport at finite temperatures

We have developed a Monte Carlo simulation for ion transport in hot background gases, which is an alternative way of solving the corresponding Boltzmann equation that determines the distribution function of ions. We consider the limit of low ion densities when the distribution function of the background gas remains unchanged due to collision with ions. A special attention has been paid to properly treat the thermal motion of the host gas particles and their influence on ions, which is very important at low electric fields, when the mean ion energy is comparable to the thermal energy of the host gas. We found the conditional probability distribution of gas velocities that correspond to an ion of specific velocity which collides with a gas particle. Also, we have derived exact analytical formulas for piecewise calculation of the collision frequency integrals. We address the cases when the background gas is monocomponent and when it is a mixture of different gases. The developed techniques described here are required for Monte Carlo simulations of ion transport and for hybrid models of non-equilibrium plasmas. The range of energies where it is necessary to apply the technique has been defined. The results we obtained are in excellent agreement with the existing ones obtained by complementary methods. Having verified our algorithm, we were able to produce calculations for Ar$^+$ ions in Ar and propose them as a new benchmark for thermal effects. The developed method is widely applicable for solving the Boltzmann equation that appears in many different contexts in physics.Comment: 14 page

Extraction of Palladium- [4-(2-Thiazolylazo)Resorcinol] Complexes and Spectrophotometric Determination of Palladium

The extraction of palladium(II) as a red camples with 4-(2- -thiazolylazo)resarciinol (TAR = H2R) by tetraphenylphasphanium chloride in chloroform was studied. Quantitative extraction was achieved in the pH region between 2 and 10. By extraction at pH 2 and by spectrophotometric measurements of the red complex in the organic phase, a sensitive and selective method for palladium determination was evaluated. An anionic complex [PdRCl]" was predominantly extracted over a wide pH range forming ion associates with tetraphenylphasphomium cation 0Lax = 525 . nm, s = 2.4 X 104 1 mol1 cm"1). The extracted complexes were studied in solution and by characterization of the isolated solid compound

Extraction of Palladium- [4-(2-Thiazolylazo)Resorcinol] Complexes and Spectrophotometric Determination of Palladium

The extraction of palladium(II) as a red camples with 4-(2- -thiazolylazo)resarciinol (TAR = H2R) by tetraphenylphasphanium chloride in chloroform was studied. Quantitative extraction was achieved in the pH region between 2 and 10. By extraction at pH 2 and by spectrophotometric measurements of the red complex in the organic phase, a sensitive and selective method for palladium determination was evaluated. An anionic complex [PdRCl]" was predominantly extracted over a wide pH range forming ion associates with tetraphenylphasphomium cation 0Lax = 525 . nm, s = 2.4 X 104 1 mol1 cm"1). The extracted complexes were studied in solution and by characterization of the isolated solid compound