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Oxidative Polymerization Studies of 8-Hydroxyquinoline in Different Media

100%

Ahmed S. M. , Ahmed S. A.

tom Vol. 81, nr 12

2195-2205

Oxidative polymerization reaction of 8-hydroxyquinoline (HQ) in different media has been studied experimentally by spectrophotometric technique and confirmed computationally by molecular mechanics (MM+) calculations. MM+ calculations showed that the PE of the optimum molecular geometric (OMG) of the anionic HQ (HQ-NaOH) form is about two (1.985) times greater than the PE in the protonated (HQ-HCl) form. PE of the OMG structure of the PHQ was computed (-30.651 kJ mol-1). These calculations indicate that the matrix is highly stable. The oxidation constant (Kox) of the anionic form (HQ-NaOH) is about twice (2.02) greater than that of the protonated (HQ-H2SO4) form. The proposed procedure was success fully applied for the oxida tion of diiodohydroxyquinoline in streptoquin (SQ) (anti-di ar rhea, tab lets). The Kox of HQ in SQ was also found to be lower than the Kox in synthetic (HQ) solution. Kinetic parameters of the oxidative polymerization of the anionic form of HQ (HQ-NaOH) were deduced on the basis of absorbance variations. The results of computer-oriented kinetic analysis indicate that the rate-controlling step of the HQ polymerization is governed by Ginstling-Bronstein equation representing the three-dimensional diffusion (D4). Activation parameters of the oxidative polymerization of the anionic form of HQ (HQ-NaOH) were computed and discussed.

Strongyloides stercoralis in patients on corticosteroids therapy using enzyme-linked immunosorbent assay and gelatin particles indirect agglutination tests: a diagnostic approach

80%

Ahmed S. A. , El-Moselhy A. , El-Moammaly A. , El-Shewy K.

Acta Parasitologica

2019

tom 64

nr 2

Centrifugal compressor performance improvement through multi splitter impeller

70%

Malik A. , Zheng Q. , Qureshi S. R. , Ahmed S. A. , Gambo D. K. B.

Polish Maritime Research

2019

tom 26

nr 2

In the paper, a back swept impeller of centrifugal compressor is experimentally studied and numerically validated and modified to increase its pressure ratio and improve efficiency, as well as to analyse the effect of splitter blade location between two main blades. The back swept multi splitter blade impeller was designed with a big splitter positioned close to the main blade suction surface and a smaller splitter close to the pressure surface. Adding this multi splitter improves the overall performance of the modified impeller due to less intensive flow separation and smaller pressure loss. In particular, the total pressure ratio was observed to increase from 4.1 to 4.4, with one percent increase in efficiency