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  • Author or Editor: A. Ali x
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Abstract  

Different atmospheric aerosol samples were collected on three types of filters. From both of the loaded and clean areas of each kind of filter, different disks were cut and investigated by XRF, PIXE and scanning electron microscopy (SEM). The blank concentration values of the elements Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br and Pb in the three types of filter are discussed. It is found that for trace elemental analysis, the Nuclepore membrane filters are the most suitable for sampling. These filters have much lower blank element concentrations than the glass fiber and ash free filters. It was found also that PIXE is a more reliable analytical technique for atmospheric aerosol particles than the other methods used.

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Abstract  

The extraction of Nd(III), Tb(III) and Lu(III) as representatives of lanthanide(III) ions with picrolonic acid (HPA) in methylisobutylketone (MIBK) has been studied from pH 1-2 buffer solutions. The composition of the organic species formed in the organic phase after extraction has been determined by slope analysis to be M(PA)3 [M = Nd(III), Tb(III) and Lu(III)]. The equilibrium constant values, log k ex

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Abstract  

3-Formyl-4-hydroxy-N-methyl 2(H) quinoline (FHMQ) was synthesized and characterized. This compound was found not soluble in water or nitric acid solutions of different concentration. The uptake of Zr and Th from nitric acid by FHMQ has been investigated. The effect of shaking time on the percent uptake was studied. It was found that the equilibrium uptake of Zr is reached in one step after 2 hrs while in case of Th 4 hrs was required to reach equilibrium. The effect of nitric acid, metal ion and FHMQ on Zr uptake was studied. Studies on the retention capacity of 3-formyl-4-hydroxy-N-methyl 2(H) quinoline showed that its capacity decreases by increasing the nitric acid concentration for both Zr and Th. From the results obtained a selective method for separation of Zr from Th and U(VI) was developed using a floating bed column.

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Abstract  

The extraction of palladium/II/ with diphenyl-2-pyridylmethane /DPPM/ in benzene has been investigated from thiocyanate-nitrate media and optimized. Thiosulphate ions showed strong interference and reduced the extraction below 1%. Separation factors determined for most of the elements were better than 103. This extraction method affords palladium preconcentration and its separation from Sc/III/, Co/II/, Cu/II/, Zn/II/, Se/IV/, Sr/II/, Ru/III/, Cd/II/, Cs/I/ and Eu/III/. Few possible applications of such separations have been cited.

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Abstract  

Different atmospheric aerosol samples were collected on three types of filters. Disks of both loaded and clean areas of each kind of filter were investigated by XRF, PIXE and Scanning Electron Microscope (SEM) methods. The blank concentration values of the elements Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br and Pb in the three types of fiters are discussed. It is found that for trace elemental analysis, the Nuclepore membrane filters are the most suitable for sampling. These have much lower blank element concentration values than the glass fibres and ash free filters. It was found also that the PIXE method is a more reliable analytical technique for atmospheric aerosol particles than the other methods.

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Abstract  

The extraction of silver from aqueous thiocyanate-perchlorate solutions using diphenyl-2-pyridylmethane (DPPM) in benzene has been investigated. The variables such as concentrations of perchloric acid, thiocyanate and DPPM influencing the extraction have been optimized. Maximum extraction has been achieved from 0.01 M perchloric acid solution containing 0.01 M potassium thiocyanate in 0.075 M DPPM in benzene. The extraction was found to be independent of silver concentration in the range from 10–4–10–6 M. The influence of several anions on the extraction was examined; only thiosulphate interfered seriously and reduced the extraction below 1%. Thus 0.1M potassium thiosulphate was found to back-extract silver quantitatively in one step. Under selected optimal conditions, very small extraction (<1%) was observed for trivalent Gd, Dy, Ho, Tm, Yb, Lu; Cs(I) and Cd(II) and separation factors for these elements were better than 103. Only Sn(IV) exhibited quantitative extraction (>99%). This extraction procedure can be used for the preconcentration of silver and tin or their separation from rare earths mentioned above.

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Abstract  

A qualitative and quantitative analysis of atmospheric deposition samples has been carried out by XRF method in Debrecen city over a long period. Seasonal variations in the fluxes of 14 elements such as Si, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Sr, Zr and Pb have been determined. Ca, Si and S elements had the greatest yearly average flux compared to other elements. The atmospheric deposition of most of the elements have higher values in summer than in winter season. Results are compared with literature data.

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Abstract  

A systematic investigation on99mTc and99Mo extraction by (C6 H5)4As+ from HCl, HBr, HNO3, and H2SO4 solutions has been undertaken. Technecium extraction was found to attain very high values at low acid concentrations, while molybdenum has negligible extraction coefficients. Consequently, at low acidities, Tc could be separated from irradiated Mo with very high selectivity. TcO 4 distribution coefficient was found to depend, however, on the nature and concentration of competing anions. For the same anion concentration, the selectivity of Tc extraction takes the sequence SO 4 2− >Cl>Br>NO 3 . Experimental results enabled a calculation of stability constant of (C6 H5)4 AsTcO4. Extraction data were used to identify parameters for a99mTc generator.

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DTA and TG has been used to study the thermal stability of cross-linked epoxidized polydienes. Cross-linking has been achieved using some derivatives of hydroxycarbostyrils, triazines and phthalimide. The new properties of the polymers after curing are interpreted on the basis of the results of DTA and TG.

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The present study was carried out for developing an efficient in vitro callus induction and plant regeneration system in four different tomato genotypes (Solanum lycopersicum Mill., previous name: Lycopersicon esculentum), Advantage II, Edkawy, Castle Rock and Super Strain B, using hypocotyl and cotyledon explants. The effects of two cytokinins, BA (benzyl adenine) and Kin (kinetin), on callus induction and plant regeneration frequency were investigated when added to MS medium in combination at varying concentrations. All concentrations of the two cytokinins were suitable for callus induction and plant regeneration. The frequency of callus induction and plant regeneration from both cotyledon and hypocotyl explants reached 100% for all tested genotypes. Cotyledons produced a higher average number of shoots per explants than hypocotyls for all the genotypes in the five concentrations of combined cytokinins. The average number of shoots per explant in Super Strain B was found to be the highest (42 and 60 for the hypocotyl and cotyledon explants, respectively). Supplementing MS medium with 1.0 mg L−1 kinetin and 1.0 mg L−1 benzyl adenine was found to be optimum for producing the highest number of shoots per explant from hypocotyls and cotyledons in the tomato genotypes investigated. The proposed medium showed a significant superiority over the reference media.

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