Search Results

You are looking at 1 - 9 of 9 items for

  • Author or Editor: M. Daud x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

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.

Restricted access

Abstract  

Size fractionated PM2.5 and PM2.5–10 airborne particulates collected from the airport housing society site in Rawalpindi were characterized using the non destructive ion beam analysis method. Proton induced X-ray emission and Proton induced gamma ray emission were employed to quantify 28 trace elements in fine and coarse filter samples. The average PM2.5 and PM2.5–10 masses were found to be 15.7 and 144 μg/m3, respectively which, when combined exceed the Pakistani limit for PM10 of 100 μg/m3. The average black carbon (BC) content was found to be 3.49 and 5.95 μg/m3 corresponding to 23.8 and 4.30% of the fine and coarse masses, respectively. The reconstructed mass (RCM) was calculated for both particle modes using 5 pseudo sources, namely soil, sulfate, smoke, sea salt and BC. It was found that 5 sources could account for 80.6 and 49.0% of the fine and coarse masses, respectively. The low value of RCM for the coarse mode may imply a much higher organic content. The major sources contributing to the fine mode were soil, sulfate and BC. Similarly for the coarse mass fraction it was found that soil was the major source whereas the sulfate and BC sources did not contribute as much.

Restricted access

Abstract  

Tuna fish flesh homogenate, IAEA-436, was received under the IAEA Analytical Quality Control Services (AQCS) intercomparison programme. Instrumental neutron activation analysis (INAA) was used to determine Al, As, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hg, K, Mg, Mn, Na, Rb, Se, Sb, Sm, and Zn in this proposed reference material (RM). IAEA-407 (Fish Homogenate) and NIST-SRM-1572 (Citrus Leaves) were used for quality assurance (QA) purposes. Due to the very low levels of most elements in IAEA-436, large discrepancies were observed between our results for IAEA-436 and data cited by the IAEA.

Restricted access

Abstract  

Natural mixture containing mostly minerals of iron, sillicon, magnesium, aluminium and calcium was exploited for the decontamination study of europium radionuclides from aqueous radioactive waste solutions. The physicochemical conditions, such as shaking and equilibration time, nature of hydrogen ions, pH, temperature, concentrations of adsorbate and adsorbent were experimentally determined. This study showed quantitative adsorption beyond pH 7 and under optimized conditions, up to 33 g of the adsorbate can be rapidly removed from radioactive effluents using only 1 kg of the mineral mixture (MM). Desorption study of the solidified radioactive waste product reveals no significant loss (< 0.01% month), indicating MM as an effective material for removal of radioactive europium and storing it in solid form over a long period of time.

Restricted access

Abstract  

Over a 1,000 pairs of coarse and fine filters were collected using Gent samplers and polycarbonate filters from three sites in Islamabad from the period 1998 to 2010. The black carbon in these samples was determined by reflectance measurement while their elemental composition were determined using the techniques of instrumental neutron activation analysis, ion beam analysis and X-ray fluorescence spectrometry. Islamabad is a well planned and relatively small city as compared to Lahore or Karachi therefore its air quality is better than the air quality of other major Pakistani cities. It was found that the new air quality standards being implemented by the Pakistani government on the 1st of January 2012 may not be attained even in Islamabad without the implementation of control and remedial measures. An overview of the elemental data obtained and calculation of enrichment factors shows that the particles in Islamabad originate from re-suspended soil, vehicular emissions and coal combustion. However further work is required for identification of pollution sources and their origin.

Restricted access

Abstract  

To study the impurity elements, which render color-induced topaz long lived radionuclides, three samples of topaz, from three different cities of the Northern Pakistan (Baltistan, Gilgit and Mardan) were analyzed using k 0 instrumental neutron activation analysis (k 0-INAA). The samples were irradiated in Pakistan Research Reactor-1 (PARR-1) and PARR-2 at Pakistan Institute of Nuclear Science & Technology (PINSTECH), Islamabad. The method was validated by analyzing IAEA-S7 reference material. In three samples a total of 22 trace level impurity elements were quantified. Among impurities, 10 elements including As, Ce, Ga, Ge, La, Na, Sb, Sc, U and Zn were common in topaz of all the three places. The storage time has been calculated for each sample required to bring the induced radioactivity down to permissible level given by US National Regulatory Commission.

Restricted access

Abstract  

This paper presents the results of the proficiency test exercise conducted in Pakistan for the determination of trace elements in mushroom reference material. Thirteen laboratories from different organizations of the country submitted trace elemental data on Al, As, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hg, K, Li, Mg, Mn, Na, P, Pb, Rb Sc, Si, Sm, Sr, Th, Zn. Results for Al, As, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Na, Rb Sc, and Zn, in the mushroom material were reported by two or more participating laboratories and could be subjected to statistical evaluation. The original data of these trace elements was subjected to a computer program “Histo Version 2.1” provided by IAEA. The four outlier tests, i.e., Dixon, Grubbs, skewness and kurtosis were applied to the data sets. Consensus (overall) mean values, absolute standard deviation, relative standard deviation, standard error, median and range of values for these elements have been reported at a significance level of 0.05.

Restricted access

Every year the library of IIUM subscribes to quite a number of online databases with huge expenses but the utilization of these databases is countable. 10 out of 53 subscriptions have been terminated by 2015 to save the cost go in vain. The purpose of this paper is to develop a model based on the ISB elements to identify the reason behind this low usage and to increase the usage of online databases in the future. It has undertaken a quantitative approach to identify the elements of ISB among undergraduate (UG) students. The primary data has been collected through questionnaires based on the variables identified in the objective. There are 118 samples participating in this research and the proposed model has been adapted from Savolainen and Wilson. Psychological perception, searching strategies and the information resources have been considered as the independent variable and measured the usage of the online database among UG students as the dependent variable. The results have shown that there are seven elements which have an influence on the usage of the online database among IIUM UG students. Despite the limited number of samples and a specific group of students, the proposed model can enhance the usage of online database system subscribed to by IIUM library and a search engine can be developed to get the usage increased. In that sense, it is recommended to involve more participants from the different levels of students and users to get diverse elements of ISB. However, the paper contributes to bridging the gap between the online database usage and the users, believed to have an effective outcome for online database subscription. It is hoped that the proposed model would significantly fill this gap and help the library to increase the number of users for their expensive databases.

Open access

Sea cucumbers are marine invertebrates of the phylum of Echinodermata that have been used in Asian traditional medicine since ancient times. This study was conducted to investigate the antioxidant and cytotoxic properties of aqueous and organic extracts from two sea cucumber species, Holothuria edulis Lesson (Holothuriidae) and Stichopus horrens Selenka (Stichopodidae). Antioxidant activities of the extracts were evaluated by DPPH· and β-carotene bleaching assays, while MTT and trypan blue exclusion assays were used to demonstrate the cytotoxic effects of the extracts against two human cancer cell lines, non-small cell lung cancer cells (A549) and esophageal cancer cells (TE1). The results showed that both aqueous and organic extracts of H. edulis were able to scavenge DPH radical (IC50 at 2.04 mg/ml and 8.73 mg/ml, respectively). Aqueous and organic extracts of S. horrens inhibited 79.62% and 46.66% of β-carotene oxidation by linoleate free radical. On the other hand, the organic extract of S. horrens exhibited the highest cytotoxic effects against A549 and TE1 cancer cells giving IC50 at 15.5 and 4.0 μg/ml, respectively. In conclusion, the present study revealed that H. edulis and S. horrens contain promising levels of antioxidant and cytotoxic natural products that might be used for cancer prevention and treatment.

Restricted access