In this work, a simple, selective and rapid Flow injection method of analysis (FIA) is developed for ultra-trace determination of palladium. The method is based on the catalytic effect of palladium on the oxidation of naphthol green B by periodate. Naphthol green B undergoes an oxidation reaction with metaperiodate in acidic medium to from a colorless product at a very slow rate. It was found that this reaction can be quickly done at the presence of trace amount of pd2+. The reaction was monitored spectrophotometrically by measuring the difference between absorbance of naphtholgreen B of solutions with and without pd2+ at the λ max = 721 nm. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. Under these conditions, the influences of some important species on the determination of pd2+ by Flow system were examined and most of them did not show any interference effect on the Flow injection determination. It is obvious that under the optimized conditions absorbance signal was linearly dependent on pd2+ concentrations in the ranges of 2. 0-90. 0 ng ml-1 with a detection limit of 0. 9 ng ml-1 (S/N = 3) and a sample rate of 35 ± 5 samples/h. The proposed method has been successfully applied for the analysis of ultra-trace amounts of pd2+ in human serum and water samples.

A fast and sensitive method for detecting resorcinol by producing yellowish-green color species using the reaction of potassium dichromate with resorcinol in a sulfuric acid medium. NAG-4SX3-3D analyzer was used to evaluate the transducer energy response. To improve the sensitivity of the newly developed approach, the relevant parameter was explored. The linear range (0.05-32) mmol.L-1 for resorcinol measurement and RSD percent for the repetition (n=6) was significantly lower than 0.3% for (0.7, 23 millimol.L-1) with L.O.D.=48.1687 ng/sample from the progressive dilution across the calibration graph's lowest concentration linear dynamic range (r=0.9997), (correlation coefficient), percentage linearity (R2 %=99.95). The proposed approach was compared to the previous technique (UV-spectrophotometric at λmax=273 nm). It can be concluded that, in addition to the technique's sensitivity (developed) and the use of a few chemicals, it outperforms the 10 mm irradiation of the classic reference method. Furthermore, continual dilution in CFIA enables the handling of high or low concentrations, opening up a larger range of applications. Based on the foregoing, the developed methodology is judged to be the most suited for resorcinol molecules compared to the reference techniques.

The purpose of this paper is to analyze the Flow field structure in transient state and performance of secondary injection system for thrust vectoring in divergent section of a two-dimensional nozzle. Secondary injection for thrust vectoring in a two-dimensional nozzle is studied by solving threedimensional Reynolds-averaged equations by means of fluent solver. Spalart-Allmaras model was used to model the fluid behavior near the walls. Density-based solver and explicit formulation are employed in the computational model. Results show that the solution of interfered field in the transient-state is more accurate than steady-state, especially in the initial injection. In addition, various testing showed that the maximum side force would be in the injection angle of twenty degrees and with increasing pressure ratio, we have more side force. At the end it was observed that by sketching the exit gases deviation according to time, we could be informed of desired secondary injection time in order to achieve required deviation around pitch axis, and the required force to achieve desired deviation angle. The innovation of this paper is the solution of interfered field in transient state, and of course the injection from the optimal point.

A simple and effective technique for detecting catechol by the generation of white precipitate utilizing the reaction of potassium dichromate with catechol in sulfuric acid medium, which is characterized by its speed and sensitivity. The NAG-4SX3-3D analyzer was utilized to measure the incident light attenuation impacting on the precipitate surface grains to quantify turbidity (0-180 degree), the snow led [LED] (blue band 400-480 nm, green band 443-600 nm, and red band 660-697 nm) was utilized to irradiate precipitate particles throughout the processes to get a transducer energy response in mV vs. time. The appropriate parameter was researched in order to increase the sensitivity of the newly devised technique. For catechol measurement, the linear range (0.01-27) millimol.L-1 with (r=0.9996), (correlation coefficient), percentage linearity (R2 percent=99.93), and RSD % for the repetition (n=6) were significantly lower than 0.2 percent (0.7, 15 millimol .L-1), with L.O.D. = 154.14 ng/sample from the progressive dilution across the calibration graph’s lowest concentration linear dynamic range. The suggested strategy was compared to the traditional method (UV-spectrophotometric at λmax=275 nm and turbidimetric method). It may be concluded that in addition to the technique’s sensitivity (developed) and the employment of few chemicals, the approach is also characterized by a dynamic system, which prevents precipitated particle setting during measurements as compared to the conventional reference method’s 10 mm irradiation. In addition, continuous dilution in CFIA allows for dealing with high or low concentrations, allowing for a wider range of applications. Based on the foregoing, the developed technique is deemed to be the most appropriate for catechol molecules when compared to the reference methods.