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  • Author or Editor: S. Rehman x
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Abstract  

Gamma irradiation studies of morin (10–5M) in ethanol and dimethyl sulphoxide (DMSO) in the dose range of 149–895 Gy and of 4.5–45 Gy were carried out, respectively, in aerated and anoxic conditions purged with nitrogen and nitrous oxide. The decoloration yield of morin was studied as a function of dose. The relative radiation sensitivity was estimated under similar conditions. The effect of the concentration (10–5–10–4M) of iodine, succinic acid and acryl amide on radiolysis of morin was investigated at constant dose in both solvents and results were interpreted in terms of scavenging reactions.

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Abstract  

An X-ray fluorescence spectrometric multivariable regression procedure is described for the determination of titanium and molybdenum in special steels and alloys in the concentration range from 9.41% down to 120 μg/g using Ti Kα1,2 and Mo Kα1,2 analyte lines. In general, better results have been achieved in first order base curve polynomials using LiF (200) crystal in combination with scintillation counter (SC) or krypton proportional counter (KPC). However, LiF (220)+SC combination also yields favorable results for Mo. The measured concentrations of Ti and Mo for BAS alloy steel standards agree very well with their certified values. The automated XRFS method for the determination of Ti and Mo appears to be free from matrix effects and is suitable for their measurement in special steels and alloys down to 120 μg/g concentration of Ti with a precision of 3.2% and an accuracy of ±2.5% and for Mo down to 350 μg/g with a precision of <1% and an accuracy of ±1.1%. The sensitivities for these lowest concentrations are calculated to be 5960 counts/mass %/s and 8000 counts/mass %/s for Ti and Mo, respectively.

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Abstract  

An X-ray fluorescence spectrometric method is described for the determination of fluorine from percent level down to 120

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line for 30 seconds using a flow proportional counter and a multilayer AXO6 crystal (2d=5.52 nm). The calibration curves of first degree base polynomials are linear over the concentration range of 8000–120 g/g and of 48.92–76% measured. The precision and accuracy obtained for polymer samples in percent level of fluorine are up to ±0.5 and within ±1%, respectively. However, the precision () for trace concentrations is in the range from 8 to 20%. In most cases the accuracy is up to ±7%, ±5% and ±4% in the concentration range of 120–8000 g/g, 801–8000 g/g and of 120–400 g/g, respectively. The time needed to analyze one sample including calibration and regression analysis is about 8 minutes.

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Abstract  

An accurate and precise wavelength dispersive X-ray fluorescence spectrometric method is described for the quantitative analysis of hafnium impurities in zirconium oxide matrix in the range from 6.8 to 1004 g/g, using the HfL1 line on 8420+ XRF Quantometer (ARL) with LiF (220) crystal and scintillation detector. The practical limit of measurement is 6.8 g/g. The precision is between 1 to 6% for higher and lower concentrations of hafnium, whereas accuracy in most cases is <5%.

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Abstract  

A direct and simple method for the conversion of UO2 and U3O8 powder into uranyl sulphate solution is described, eliminating many tedious chemical steps. UO2 and U3O8 are not soluble in concentrated or dilute sulphuric acid, as uranium in lower oxidation state does not react with sulphuric acid. However, nitric acid oxidizes uranium from lower valency to higher valency state, i.e., tetravalent to the hexavalent uranyl ion in solution. Sufficient amount of sulphuric acid present in the reaction mixture makes it possible for uranyl ions, formed by oxidation of nitric acid, to react with sulphuric acid forming uranyl sulphate.

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Abstract  

A series of octahedral complexes, [M(EDDA)(H2O)2] · H2O (where, M+2 = Co(II), Cu(II), Ni(II) and Zn(II); EDDA, ethylenediamine-N,N′-diacetate), was prepared and studied by means of thermogravimetry (TG) and differential thermal analysis (DTA). Their compositions were investigated by elemental analysis in order to ensure their purity and structural elucidation was based on spectral and magnetic properties. Thermal decomposition of these distorted octahedral complexes, [Ni(EDDA)(H2O)2], [Co(EDDA)(H2O)2] · H2O, [Cu(EDDA)(H2O)2] · H2O and [Zn(EDDA)(H2O)2] · H2O came of in one, two, three and four steps, respectively, upon heating to 800 °C, with the loss of organic and inorganic fragments. Ligand decomposed in three steps. The thermal degradation of all the complexes in static air atmosphere started at temperatures lower than those observed for the free ligand degradation (Ni-complex being the only exception). The composition of intermediates formed during degradation was confirmed by microanalysis and IR spectroscopy. The residues corresponded to metal oxide except for Ni(II) and Zn(II) complexes. It was found that thermal stability of the complexes increased in the following sequence:

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Abstract  

The special materials like phosphor bronze for P, Fe, Ni, Cu, Zn, Sn and Pb; mild steel for P, S, V, Cr, Mn, Co, Ni, Cu, As, Nb, Sb and W; special alloys for Ti and Mo, zircaloy and zirconium oxide for Hf; and zircon ore for Zr have been analyzed by X-ray fluorescence spectrometry (XRFS). The measured values along with certified values, precision and accuracy have been given for all the elements analyzed. Some of these materials have also been analyzed by atomic absorption spectrometry (AAS), neutron activation analysis (NAA) and inductively coupled plasma emission spectrometry (ICP-ES). The analytical data of XRFS are in agreement with the results obtained by AAS-ICP-ES and NAA. In most cases the precision is within ±2% and accuracy is ±4%. The precision and accuracy for S, P, Ni and Hf are poor at low concentrations. Practical low detection limit of about 40 g/g of Hf in zirconium matrix has been achieved. It is established that precise and accurate determination of Ti and Mo in special alloys is possible using XRFS.

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Abstract  

The iodide complexes of transition metals with 1,2-diimidazoloethane (DIE) of the general formula MLI2, (M=Cu(II), Hg(II), Cd(II); L=1,2-diimidazoloethane) were prepared and studied by means of thermogravimetry (TG/DTG) and differential thermal analysis (DTA) techniques. Their compositions were investigated by elemental analysis in order to ensure their purity and structural elucidations were based on conductivity measurements, room temperature magnetic measurements, proton NMR, XRD and IR spectra. Thermal decomposition of these distorted tetrahedral complexes and the ligand took place in two distinct steps upon heating up to 800�C, with the loss of inorganic and organic fragments. The thermal degradation of all the complexes (except for cadmium complex) in static air atmosphere started at temperatures lower than those observed for the free ligand pyrolysis. The composition of intermediates formed during degradation was confirmed by microanalysis and IR spectroscopy. The residues after heating above 740�C corresponded to metal oxide except for Hg(II) complex, which behaved differently. It was found on the basis of thermal analysis that thermal stability of the complexes increased in the following sequence: Hg(II)<Cu(II)<Cd(II).

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The allelic variation for Glu-1, Glu-3 loci and presence of IBL-1RS translocation was determined in 126 spring wheat accessions. The most common alleles at Glu-1 loci were Glu-A1b (59.52%), Glu-B1c (41.26%), and Glu-D1d (57.14%) and at Glu-3 loci were Glu-A3c (56.45%), Glu-B3j (29.36%), and Glu-D3b (76.98%). Modern Pakistani wheat varieties carried superior alleles at Glu-1 and Glu-3 loci for bread-making quality and had no negative influence of secalin protein-synthesized by 1BL-1RS translocation. For LMW-GS, the most common combination was Glu-A3c, Glu-B3j and Glu-D3b. The loci Glu-B1 and Glu-B3 had the highest allelic diversity of Glu-1 and Glu-3 loci, respectively.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Siddique, M. Anwar-ul-Islam, N. Butt, N. Hussain, S. Rehman and M. Arshed

Abstract  

Room temperature corrosion studies have been made on the rust of commercially available mild steel in a simulated acid rain environment using the method of transmission Mössbauer spectroscopy. The main corrosion products identified are α-FeOOH, γ-FeOOH, and a product with unfamiliar parameters which seems to be amorphous in nature (being very large linewidth −2.5 mm/s) and may be considered as an intermediate phase. A small amount of γ-Fe2O3 (6–8%) is also observed.

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