Dietary evaluation of toxic elements through integrated diet

Several potentially toxic trace elements, namely, Hg, Pb, Cd, As, Sb, Br and Se have been measured by INAA in combination with AAS techniques in the integrated diet representative of the inhabitants of Gujranwala, a highly industrialized city of Pakistan. The dietary intake values for these elements have been estimated from the prevailing concentration level in the summer and winter season diets, which reveals that present intake data are well within the reported WHO values and can be considered to be safe. Posslble sources of food contamination by the toxic elements and their adverse impacts on human heaith are briefly discussed.     

Correlation of plasma electron temperature with neutron emission ina low-energy plasma focus

Correlation of neutron emission with plasma electron temperature in a low-energy (2.3 kJ) plasma focus is investigated. To determine the plasma temperature by continuum X-ray analysis, cobalt is selected as the filter, which discriminates the line radiation from the background impurities like carbon, nitrogen, and oxygen, or the copper of which plasma focus electrodes are made. For a pressure range of high neutron emission (1-4 mbar), the neutron yield is found to correlate with the plasma temperature. The highest temperature recorded is 5 keV at 2.5 mbar, the filling pressure for the highest neutron emission in this device     

MHD flow and heat transfer of a micropolar fluid over a stretching surface with heat generation (absorption) and slip velocity

In this work, the effects of slip velocity on the flow and heat transfer for an electrically conducting micropolar fluid over a permeable stretching surface with variable heat flux in the presence of heat generation (absorption) and a transverse magnetic field are investigated. The governing partial differential equations describing the problem are converted to a system of non-linear ordinary differential equations by using the similarity transformation, which is solved numerically using the Chebyshev spectral method. The effects of the slip parameter on the flow, micro-rotation and temperature profiles as well as on the local skin-friction coefficient, the wall couple stress and the local Nusselt number are presented graphically. The numerical results of the local skin-friction coefficient, the wall couple stress and the local Nusselt number are given in a tabular form and discussed.     

Simultaneous determination of hafnium and zirconium in low grade uranium ores using INAA

A non-destructive neutron activation analysis technique has been developed for the determination of hafnium and zirconium in low grade uranium ores. In order to calculate the fission contribution of²³⁵U, thermal neutron absorption cross-section /_a/ for⁹⁴Zr has been determined. The study shows that 1 g of uranium produces the same activity as from 10.03 g of zirconium. Based on this fact, the degree of interferences have been calculated for each sample and the necessary corrections have been applied. The values have been compared with the reported IAEA and NBS values.     

Optical Emission Spectroscopy of Abnormal Glow Region in Nitrogen Plasma

Optical emission spectroscopy of the active species in N₂ plasma is carried out to investigate their concentration as a function of discharge parameters such as filling pressure (2.0–7.0 mbar), source power (100–200 W) and gas flow rate (50–300 mg/min). The primary motivation of this work is to obtain reliable information about the concentration of the active species of N₂ plasma, which play an important role in plasma surface nitriding processes. Emission intensity from the selected electronic excited states of molecular and atomic species is evaluated as a function of discharge parameters to investigate their concentration. The emission intensity ratio I(N₂⁺)/I(N₂) and I(N⁺)/I(N) of the electronic transitions is also evaluated as a function of discharge parameters to investigate the relative dependence of their concentrations. It is observed that the concentration of the active species of N₂ plasma is strongly affected by the filling pressure and source power whereas flow rate has no significant effect. An increased occurrence of N₂⁺ molecular ions in comparison with N₂ molecules, and N⁺ ions in comparison with N atoms is observed with source power whereas decreased occurrence of N₂⁺ molecular ions in comparison with N₂ molecules, and N⁺ ions in comparison with N atoms is observed with the rise in filling pressure.     

INAA for the characterization of airborne particulate matter from the industrial area of Islamabad city

Air particulate matter (PM) was collected in two size fractions using stacked filter units (SFUs) provided by the International Atomic Energy Agency (IAEA) from the industrial area of Islamabad. Nucleopore polycarbonate filters were used for collecting from Oct 98 to Jun 99 the particulate matter in coarse and fine size fractions. The samples were characterized by the instrumental neutron activation analysis (INAA). About 33 elements were quantified using different irradiation and counting protocols.     

Instrumental neutron activation analysis of different products from the sugarcane industry in Pakistan--part 1: essential elements for nutritional adequacy

Jaggery, brown sugar, white sugar, and molasses collected from the local sugarcane industry of Pakistan have been analyzed for essential elements in order to estimate their nutritional adequacy. Instrumental neutron activation analysis was used to determine Ca, CI, Co, Cr, Fe, K, Mg, Mn, Na, and Zn through sequential, short, medium, and long irradiation times. Maximum concentrations for most of these elements were determined in molasses, with lower concentrations determined in jaggery and brown sugar; white sugar contained trace amounts of all essential elements. Contributions to the weekly Recommended Dietary Allowance (RDA) values for the elements were estimated only for jaggery, brown sugar, and white sugar because molasses in Pakistan is not consumed as a dietary item. Jaggery contributes the highest percentages of Cr, Mg, Mn, and Zn, whereas the highest percentages of Cl, Fe, K, and Na can be acquired from brown sugar. The contribution of white sugar to the weekly RDAs for these elements is negligible, indicating that white sugar is a poor source of the essential elements. However, the introduction of molasses to the diet can contribute to an adequate intake of these elements.