Proton induced K-shell ionization cross sections for a wide range of elements (4 ≤ Z ≤ 92) within ECPSSR theory and updated experimental data

AbstractWithin the individual treatment of the elements from beryllium (4Be) to uranium (92U), the experimental databases are normalized to their corresponding values of the ECPSSR model to deduce the semi-empirical cross sections. These databases rely on the different compilations available in the literature and on the other data extracted from papers published from 1953 till 2010. In the present paper, a fourth order polynomial was used to fit very well the existing normalized database of K-shell ionization cross sections by proton. These procedures generate a new set of parameters for the sake of the quick calculation of the semi-empirical cross sections. A comparison is made between the deduced results and those obtained by using the ECPSSR model where a remarkable discrepancy is observed at low-proton velocity regime especially for the lightest elements

Hafnium to thorium M-shell X-ray production cross sections by proton impact

Theoretical M-shell X-ray production cross sections have been calculated within the ECPSSR model. The semi-empirical cross sections are then deduced by fitting the available experimental data normalized to their corresponding theoretical values for elements with 72 ≤ Z ≤ 90 by proton in the energy range 0.1–4.0 MeV. Also, an analytical formula has been used to calculate the empirical X-ray production cross sections by direct fitting of the same experimental data, which are found to be universal, both for individual and collective fits. On the other hand, based on the individual fitting which gives the reliable cross sections, we attempt to deduce another new empirical cross sections by assuming that the ratio empirical to ECPSSR of the cross sections is roughly the same for all elements. In addition, our results are presented for selected heavy elements, namely 74W, 79Au and 83Bi, being the most extensively studied. Finally, a comparison is made between the different procedures followed here and the experimental data. Keywords: M-shell X-ray production cross sections, ECPSSR theory, Semi-empirical and empirical cross section

Electron slowing down in solid targets: Monte-Carlo calculations

We have performed Monte-Carlo simulations of slow electrons impinging on semi-infinite aluminum and copper in the energy range 0.5–4 keV. We present results for the backscattering coefficients, mean penetration depths and stopping profiles. Our results for the backscattering coefficients agree well with the experimental data within the limits of the statistical accuracy. The slight discrepancy between simulated and experimental results regarding the mean penetration depth is discussed

Étude comparative de l’adsorption d’un colorant de cuve sur différents adsorbants à base d’un matériau inorganique la Bentonite et l’argile de la région de M’sila

International audienceThe present work aims to reduce the impact of vat dyes by a natural and activated Algerian clay using the adsorption technique. The adsorption experiments show that the clay used is very effective in removing the vat dye at relatively low concentrations in an aqueous medium. The adsorption isotherms of the vat dye on the raw clay are satisfactorily described by the Langmuir model. Adsorption capacities in the range of 55.25 mg. g(-1) for crude bentonite (BB), 55.20 mg. g(-1) for sodium bentonite (BS), 51.78 mg. g(-1) for red clay (AR) and 48.24 mg. g(-1) for Madadid clay (AM) were determined from the Langmuir isotherm. These values show that the raw bentonite has a better adsorption capacity because it contains a large percentage of clay fraction

Étude de l’effet du temps de traitement alcalin de fibres palmier sur le comportement mécanique des matériaux à base d’argile rouge de la région de M’sila

Ce travail s’inscrit dans le développement de matériaux locaux, telle que la fibre végétale (fibre de palmier) et l’argile rouge du sud Algérien, largement utilisées dans la préparation des briques, comme matériaux de construction rurale. Les fibres végétales possèdent des propriétés très intéressantes, elles sont : renouvelables, biodégradables et le rapport coût/légèreté faible. Leurs propriétés mécaniques sont très importantes. Cependant, le problème prédominant dans ce type de matériaux composites est la faible adhésion de l’interface matrice-fibre, attribuée probablement, à la nature de la surface et au caractère hydrophobe des fibres naturelles, conduisant ainsi, à des propriétés mécaniques faibles pour le composite envisagé. Le but de cette étude consiste à traiter la fibre de palmier par une solution basique d’hydroxyde de sodium (NaOH 4 % [m/v]) durant des périodes variables : 3, 7, 24 et 48 heures, afin d’améliorer l’adhésion interfaciale. Les résultats obtenus à partir des essais réalisés sur le composite renforcé par les fibres de palmier traitées durant 7 h ont montré une nette augmentation quant à la résistance, à la flexion et à la compression ; cette croissance est respectivement de l’ordre de 57 et 60 %, comparativement au composite renforcé par les fibres non traitées. On peut déduire que les fibres de palmier peuvent être considérées comme l’un des matériaux appropriés pour le renforcement de l’argile

New procedure calculation of photon-induced Kβ/Kα intensity ratios for elements 16S to 92U

In this paper, the measured Kβ/Kα intensity ratio values published in the literature from 1980 to 2011 have been reported. The weighted- and unweighted-mean values of the experimental data were fitted by the analytical function to deduce new semiempirical and empirical intensity ratios in the atomic range of 16 ≤ Z ≤ 92. The semi-empirical intensity ratios were then deduced by fitting the experimental data normalized to their corresponding theoretical values and the experimental data were directly fitted to deduce the empirical ones. The results were compared with the other theoretical and experimental values reported in the literature

The effect of chemical treatment on the mechanical and thermal properties of composite materials based on clay reinforced with sawdust

This study investigates the effect of the chemical treatment of sawdust on the mechanical and thermal properties of a clay composite reinforced with sawdust in variable mass proportions: 0.5, 1, 1.5, 2 and 2.5%, intended for use as brick in rural houses in desert areas. The sawdust was chemically treated with 5 wt% NaOH and 0.01 wt% KMnO4 solutions. The mechanical test results of the reinforced composite with alkali-treated sawdust show an increase in flexural and compression strength, reaching a maximum value of 0.89 and 4.85 MPa, respectively. However, the thermal test results show a significant decrease in the thermal conductivity of the sawdust-reinforced composite. The best result recorded is that of untreated sawdust, which has a value of 0.37 (W.m−1.K−1) compared to the one reinforced with treated sawdust

Empirical L Shell Fluorescence Yields for Elements with 40 ≤ Z ≤ 92

Based on the fact that ratio of ionization to X-ray production cross-sections are independent of the excitation energy of projectile for a given target, we have deduced a new values of L shell average fluorescence yield from existing experimental compilation (till 2014) for a wide range of elements (40 ≤ Z ≤ 92) by proton impact (up to 10.0 MeV) of ionization and X-ray production cross-sections which are found to be universal when plotted as a function of the scaled velocity of projectile. The obtained empirical cross-sections are found reliable and then exploited to derive new values of average fluorescence yield. The obtained values are compared with earlier theoretical and experimental results and an agreement is observed for all elements