In this study, optimization of advanced square wave alternative current GTAW(ASW-AC-GTAW) parameters were conducted to improve localized corrosion resistance of AA6082-T651 aluminum alloy welds. To this objective, positive half cycle current(PHC), negative half cycle current(NHC), frequency(F) and positive half cycle current percentage(PHC%) were selected as main welding parameters and altered at three levels according to Taguchi method and L9(34) orthogonal array. To study the localized corrosion resistance of weld metals; potentiodynamic polarization test was performed on all samples and corresponding Δ Epit(𝐸 𝑝 𝑖 𝑡 − 𝐸 𝑐 𝑜 𝑟 𝑟 )(𝑚 𝑉 ) were measured and considered as evaluation criterion. Implementation of variance analysis(ANOVA) on measured data and SN⁄ (Signal-to-Noise) ratios indicated that the optimum levels of PHC, NHC, F, and PHC% were 300A, 190A, 2Hz, 40%, respectively. According to ANOVA of SN⁄ ratios, contribution of PHC, NHC, F, and PHC% to the results were 35. 05%, 25. 98%, 23. 57%, and 15. 27%, consecutively. Interval domain for average Δ Epit calculated with 95% confidence level to be (379. 4, 386. 54) (mV). confirmation sample was welded under optimum condition. The values of Δ Epit of optimum sample were 381. 13 and 385. 47 mV. Both of this measurement fallen in the Interval domain. Therefore, the experimental results were in excellent agreement with analytical predictions. The regression model for predicting 𝛥 𝐸 𝑝 𝑖 𝑡 values was obtained using multivariate nonlinear regression.

In this paper, propagation of an electromagnetic beam wrapped around the axis of a thin axisymmetric wave guide embedded in a square law medium, depending on a b2 parameter small enough to make the b2n terms negligible for n  ³ 2 has been analyzed. To solve Maxwell's equations in this wave guide, a paraxial approximation of the wave equations, satisfied by the electric and magnetic components of the electromagnetic field, has been used. The solutions of the corresponding paraxial wave equations describe beam propagation by a series expansion of Gaussian modes.

A fast, simple and sensitive square-wave voltammetric (SWV) method for the determination of trace amounts of furazolidone (FZ) in urine is reported. A three-electrode system containing stationary mercury dropping (SMDE) working electrode, Pt auxiliary electrode and Ag/AgCl reference electrode was used throughout. Briton-Rabinson buffer solution is used as both pH adjusting agent and supporting electrolyte. The calibration graph showed good linearity in the concentration range of 20-900 ng ml-1 of furazolidone with a regression coefficient of 0.9996. The equation D(i) = 0.0095CFZ + 0.234 was used for calculation of furazolidone concentration in the sample solution, where CFZ is the concentration of furazolidone in ng ml-1 and D (i) is the difference between voltammogram peak currents of sample and blank solution. The RSD for 8 replicate measurements of a 60 ng ml-1 solution and LOD of the proposed method were found to be 2.2% and 5.2 ng ml-1, respectively. The procedure was successfully applied to the determination of furazolidone in urine samples.

Oblique propagating electromagnetic whistler mode instability has been studied having a k vector at angle to ambient magnetic field for bi-Maxwellian distribution function with parallel AC electric field in the magnetosphere of Uranus. The dispersion relation and growth rate have been calculated for plasma parameters suited to the magnetosphere of Uranus by using the method of characteristic solutions and kinetic approach. The effect of AC electric field and temperature anisotropy for oblique propagating electromagnetic whistler mode instability has been reported and discussed in the results and discussion section. The comparisons have been made with observations made by Voyager 2. It is found that whistler mode emissions observed at lower radial distances cannot reproduce in our calculations. The present studies should be helpful in making estimates on the scattering properties of whistler mode waves and, thus, contribute to a better understanding of auroral activity in the planetary atmosphere.

In this study, a simple and reliable square wave voltammetric (SWV) method was developed and validated for determination of diclofenac in pharmaceutical preparations and human serum. The proposed method was based on electrooxidation of diclofenac at platinum electrode in 0. 1 M TBAClO4/acetonitrile solution. The well-defined two oxidation peaks were observed at 0. 87 and 1. 27 V, respectively. Calibration curves that were obtained by using current values measured for second peak were linear over the concentration range of 1. 5-17. 5 μ g mL-1 and 2-20 μ g mL-1 in supporting electrolyte and serum, respectively. Precision and accuracy were also checked in all media. Intra-and inter-day precision values for diclofenac were less than 3. 64, and accuracy (relative error) was better than 2. 49%. Developed method in this study is accurate, precise and can be easily applied to Diclomec, Dicloflam and Voltaren tablets as pharmaceutical preparation. Also, the proposed technique was successfully applied to spiked human serum samples. No electroactive interferences from the endogenous substances were found in human serum.