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  • Author or Editor: S. Ahmad x
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Thirty-day-old plants of Lens culinaris (L.) Medic. cv. Pusa-6 were sprayed with 10-10, 10-8 or 10-6 M aqueous solutions of 28-homobrassinolide (HBR). Root length and nodule number per plant decreased, whereas the leaf nitrate reductase activity (E.C. 1.6.6.1) at 60, 90 and 120 days after sowing and the seed yield at harvest increased significantly in plants sprayed with either concentration of HBR. The values increased at first with an increase in the concentration of HBR but decreased with a further increase above 10-8M, which proved best for improving seed production.

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The use of a naturally available Lateritic Soil (LS) for the removal of mercury from industrial effluents has been investigated. Adsorption of Hg on LS from aqueous solution is reported, describing the effect of equilibration time, hydrogen ions, adsorbent and adsorbate concentration. The contact time required is less than two minutes and adsorption capacity is 15 g/kg.

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The extraction properties of Th/IV/, Pa/V/, U/VI/ and Np from nitric acid solutions into 1-phenyl-3-methyl-4-benzoylpyrazolone-5 /PMBP/ in toluene were studied, using singlestep batch and continuous H-centrifuge methods. The effects of acid and extractant concentration, temperature and phase contact time on the extraction were investigated.

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This study provides useful information about the level and chemical composition of particulate matter and about the possible sources of the aerosol pollutant in Islamabad, the capital of Pakistan. Atmospheric aerosol samples were collected during winter (January and February) 1995, from two locations of Islamabad, namely of Sector F-7 and Sector I-9. Twenty-four elements were detected by using thermal neutron activation analysis (NAA) and atomic absorption spectrometry (AAS). The concentration of total suspended particulates (TSP) in the area around the industrial sector (I-9) was found to be more than twice higher (297 μg/m3) than in the Sector F-7 (133 μg/m3). The enrichment factor analysis revealed Zn, As, Br, Sb, I and Pb, originated mainly from anthropogenic sources. The elemental ratio analysis indicated that both Sectors I-9 and F-7 are under the influence of coal burning processes whereas transportation is responsible for the toxic pollutants Pb and Br. The present results were discussed and compared with those of the literature. The results may also serve as base line level as this work employed samples collected in 1995 and many of the air environmental change factors occurred after the sampling year.

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A rapid and simple method for the determination of iodine from water has been described which is based on preconcentration of iodine with 0.1M solution of 4-(5-nonylpyridine) in benzene or carbon tetrachloride from 1–2M HNO3 followed by neutron irradiation and gamma-ray activity measurements. A clinical survey of endemic goitrous area has also been made to find a possible correlation between the endemic goiter and iodine deficiency in water.

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Instrumental neutron activation analysis has been used to evaluate potentially toxic trace element concentrations in twenty-three individual food items commonly consumed in a high altitude region (Kashmir) as a continuation of our previous study. Elemental intake levels of As, Br, Hg, Sb, and Se per person per day in meat, poultry, food grains, vegetables, fruits and milk have been calculated to assess the safety of dietary intake of these items. The dietary intake values have also been compared to the RDA levels. The data will provide the base-line levels of toxic elements in food items of this region. It will also help the dieticians to formulate safe and adequate diets for the residents of this region.

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A sensitive radiochemical procedure has been developed for the separation and determination of Dy, Sm, Gd, Eu, La and Lu in high purity uranium. The method is based on quantitative extraction of uranium using NPy/benzene as an extractant from 7M HCl solution. Rare earth elements (REE) remaining in the aqueous phase were subsequently determined by INAA.

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Instrumental neutron activation analysis technique has been used to determine the concentration levels of 12 trace elements in human head hair samples collected from 105 individuals living in various areas of Rawalpindi-Islamabad. The data show that the average concentrations of Mn, Co, Ag and Au are higher in the female group as compared to the male group. Four individuals were found to have elevated levels of Se due to the use of anti-dandruff shampoos, whereas two individials had elevated levels of Hg.

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Abstract  

An instrumental neutron activation analysis technique has been developed for the simultaneous determination of up to 30 elements including major, minor and trace elements in Obsidian Rock (a proposed NBS-SRM-278). INAA method involves both short and long irradiations followed by gamma-ray activity measurement with a Ge(Li) detector. The accuracy of the procedure has been checked by analyzing IAEA Reference Materials.

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