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  • Author or Editor: M. Misdaq x
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Abstract  

K, Cl, P, Mg and Na contents in natural red beet samples have been determined by 14 MeV neutron activation analysis. Interfering reactions were found to be negligible. Good agreement has been obtained with flame spectrometry. The kinetics of absorption and exsorption of these elements was studied in beet samples treated in different chemical solutions. The regulating role of Ca in these migrations has been confirmed. The presence of Hg limits the penetration of K and Cl as well as increases the exsorption of Na, P, Cl, K.

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Summary  

The 238U and 232 Th concentrations were measured in various potable water samples collected from various cities in Morocco using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). The measured 238U and 232 Th concentrations ranged from 0.37±0.02 to 13.60±0.97 mBq . l-1 and 0.33±0.02 to 7.10±0.49 mBq . l-1, respectively. Alpha-activities due to annual 238U and 232 Th intakes were assessed in various compartments of the human body of adult members of the Moroccan population using ICRP biokinetic models. The equivalent doses due to annual intakes of 238U and 232 Th were evaluated. The influence of the target tissue mass and the activities of 238U and 232 Th on the annual committed equivalent doses in the compartments of the human body was investigated.

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Abstract  

A new Monte Carlo computer code was developed for determining the detection efficiencies of the CR-39 and LR-115 II solid state nuclear track detectors (SSNTD) for a-particles emitted by radon (222Rn) and thoron (220Rn) series inside the atmosphere of dwelling rooms. Alpha-activities due to radon, thoron and their decay products, were evaluated for the determination of the detection efficiencies of the SSNTD utilized for the emitted a-particles by measuring the corresponding track densities. The influence of the ventilation rate and building material on the concentration of radon, thoron and their progenies was investigated. Equilibrium factors between radon and its progeny and between thoron and its daughters have been evaluated in the air of the rooms.

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Abstract  

Uranium and thorium contents were determined in samples of various plants in the soils in which the plants were grown, and in herbal infusions made by boiling the plants in potable water, using CR-39 and LR-115 solid state nuclear track detectors. In addition, radon and thoron alpha-activities per unit volume inside the plants, soils and herbal infusions were measured. These measurements were completed by an investigation of the radon transfer between soils and plants and that between plants and herbal infusions, and also by the investigation of the influence of pollution due to different material dusts on the radon and thoron alpha activities inside the plants and their infusions.

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Abstract  

Samples have been collected from different layers in a sedimentary phosphatic deposit and sieved. Different granulometric fractions have been selected. The uranium and thorium contents have been determined in each phosphate sample and its corresponding selected fractions. Radon (222Rn) α-activities per unit volume have been evaluated inside and outside each phosphate sample and its corresponding selected fractions by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD). The radon emanation coefficient in each phosphate layer has been determined and the global radon alpha activity outside a parallelepipedic block of the layers studied was evaluated. The influence of the lithology and granulation on the radon emanation has been studied.

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Abstract  

Occupancy percentages of carbon atoms at trace levels in the Ga1–xAlxAs lattice have been determined by irradiating the crystal by a 2.7 MeV deutron beam and exploiting ratios of channeled to random yields for the 100 and 110 directions. The influence of the aluminium content on carbon atoms occupancies on centred and displaced tetrahedral as well as octahedral sites occupancies has been measured. Stopping powers of Ga1–xAlxAs for the incident particles from the 100 and 110 direction irradiations have been determined.

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Abstract  

Uranium and thorium contents as well as radon and thoron -activity concentrations were evaluated inside different underground water samples by using a method based on calculating the CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs) detection efficiencies for the emitted -particles and measuring the resulting track density rates. The validity of the SSNTD technique utilized was checked by analysing uranium nitrate standard solutions. A relationship between water radon concentration and recharge of wells dug in two Moroccan Atlantic coastal regions, for a given lithology, was found. The influence of the lithology and depth on radon concentration and salinity of well waters studied was investigated.

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Abstract  

Radon -activities per unit volume have been measured in different drinking water samples belonging to different aquifers and sources by using CR-39 and LR-115 solid state nuclear track detectors (SSNTD). Radon initial equivalent -dose rates due to water ingestion have been evaluated in the stomach assuming that all the radon ingested appears in this organ. The influence of the origin and quality of the water samples studied has been investigated. Committed equivalent doses have been determined in different human organs by using dosimetric compartment models. The influence of the radon mean residence time on the committed equivalent doses in the different compartments of the gastrointestinal system has been studied. The committed equivalent dose per unit activity of radon ingested has been evaluated in the stomach tissue and compared with literature data.

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Abstract  

Uranium and thorium contents in different layers of stratigraphical sedimentary deposits have been evaluated by using LR-115 type II and CR-39 solid state nuclear track detectors (SSNTD). A method has been developed for determining the alpha-dose rates of the sedimentary travertine samples. Using the U/Th dating method, we succeeded in age dating carbonated level sampled in the sedimentary deposits. Correlation between the stratigraphy, alpha-dose rates and age has been investigated.

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Abstract  

Kodak LR-115 type II solid state nuclear track detectors (SSNTD) have been used for determining uranium contents in different phosphatic sedimentary rock samples. These samples belong to different stratigraphic layers from the upper Cretaceous to Paleogene in the Marrakech neighboring High Atlas north flank area. Interesting information has been obtained on the sedimentological conditions of uranium concentration in the geological sites.

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