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  • Author or Editor: M. Berrada x
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Abstract  

The applicability of 14 MeV neutron activation analysis for the determination of K in beet has been investigated by measuring the 2.167 MeV gamma-line from the decay of38gK produced in the39K(n, 2n) reaction. Beet samples were treated in different solutions of KCl and HgCl2 to study the diffusion of K+ ions into the beet cells. The contribution of the gamma-line to the measured peak area from38Cl produced in the37Cl(n, γ) reaction was found to be 1%. Results obtained by fast neutron activation analysis and by flame spectrometry have been compared, and good agreements were found.

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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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Abstract  

The yield and average cross section for the reactions11B(p, n)11C,12C(p, )13N,13C(p, n)13N, 12 12 C(d, n)13N,14N(p, )11C,16O(p, )13N,16O(d, n)17F,16O(t, n)18F, and18O(p, n)18F have been measured in different compounds. The charged particles were created in the samples themselves either through recoil by scattering of 14 MeV neutrons off hydrogen and deuterium, or by the (n, t) reaction on6Li using thermal neutrons. The yields of reactions12C(d, n);16O(p, );16O(t, n) and18O(p, n) have been measured using proton, deuteron and triton spectra generated by 14 MeV neutrons in the reactions D(n, p)2n;6Li(n, d);7Li(n, d) and10B(n, d);7Li(n, t) and10B(n, t), respectively.

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Abstract  

A gamma-spectrometric method independent of radon escape for the determination of U and Ra in rock samples based on the 63 keV and 1001 keV as well as 185 keV lines is described and discussed. A simple experimental procedure is given for the determination of the self-absorption factor. The method has been applied for the determination of uranium and radium in rock samples from Morocco containing uranium between 17.5 wt.% and 0.026 wt.%. The limits of determination, at 95% confidence level and 10% standard deviation, for the 63 keV and 1001 keV lines were found to be 0.075 wt.% and 0.62 wt.%, respectively, using samples of 6 g and chosing 1 h measuring time.

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Abstract  

The oxidation of pure and recycled polyethylene samples was studied by thermal analysis (DTA-TG-DSC): presence of two exothermic peaks and mass loss. The thermo-oxidation products, containing C-O and C=O links, were identified by IR spectrometry and GC-MS spectrometry. The oxidation is easier from low to high density polyethylene.

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