New Page 1 A chemiluminescence system is described for the determination of nitrite ion based on new designs for an ozone generator, liquid-gas separator and chemiluminescence reaction cell. The method is based on the gas-phase chemiluminescence reaction between ozone and nitric oxide, which is generated from the reduction of nitrite with iodide in sulfuric acid solution. The efficiency of the system was evaluated by investigation of the analytical performance characteristics of the system for nitrite determination in batch and Flow injection procedures. Under optimal conditions, the chemiluminescence response of the system was linear against the nitrite concentration over the range 1 to 1 ´ 104 ng ml-1 in the batch procedure and 10 to 5 ´ 103 ng ml-1 in the Flow injection procedure, with detection limits of 1 and 10 ng ml-1, respectively. The method is highly selective and allows for the determination of nitrite in the presence of high concentrations of several cationic, anionic and nitrogen containing species. It has been successfully applied to the analysis of nitrite in natural water and soil extracts.  

In this paper, the application of the surface mass transfer optimization in shock wave-boundary layer interaction control at off-design conditions of transonic aircraft wing is presented. The suction or injection parameters include for example its position on the airfoil, its angle, the length of the hole and the rate of the injected or sucked Flow. The optimization process is carried out using an efficient Genetic Algorithm (GA) method. The compressible viscous Flow equations in Reynolds Averaged form are solved together with a twoequation k-epsilon turbulence model to accurately compute the objective function. Four different objective functions are introduced including maximum lift to drag ratio, minimum drag coefficient, maximum lift to drag ratio with no drag increment and minimum drag coefficient with no lift decrement. Effectiveness of each objective function is examined by comparing the optimum results in terms of the Flow control parameters and Flow characteristics.

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.