Algebraic treatment of the confluent Natanzon potentials

Using the so(2,1) Lie algebra and the Baker, Campbell and Hausdorff formulas, the Green's function for the class of the confluent Natanzon potentials is constructed straightforwardly. The bound-state energy spectrum is then determined. Eventually, the three-dimensional harmonic potential, the three-dimensional Coulomb potential and the Morse potential may all be considered as particular cases.Comment: 9 page

Combinaison de codeurs par algorithme génétique : Application à la vérification du locuteur

Le domaine de la vérification du locuteur regroupe les applications pour lesquelles on désire identifier l'identité d'une personne à partir de sa voix. Le champ d'application couvre de nombreux secteurs tels que l'accès sécurisé, les transactions téléphoniques, la surveillance, l'indexation audio ou encore l'expertise judiciaire. Notre étude porte sur l'étape d'extraction de caractéristiques du système de reconnaissance du locuteur. Ce module a pour fonction d'extraire du signal de parole les informations pertinentes du point de vue de la discrimination inter-locuteur. Nous proposons dans cet article d'utiliser un algorithme génétique pour optimiser un système d'extraction de caractéristiques adapté à la reconnaissance du locuteur. La méthode proposée permet d'obtenir une amélioration significative du taux de reconnaissance sur la base Nist SRE 2005

Klein's Paradox

We solve the one dimensional Feshbach-Villars equation for spin-1/2 particle subjected to a scalar smooth potential. The eight component wave function is given in terms of the hypergeometric functions and via a limiting procedure, the wave functions of the step potential are deduced. These wave functions are used to test the validity of the boundary conditions deduced from the Feshbach-Villars transformation. The creation of pairs is predicted from the boundary condition of the charge density.Comment: 18 pages, Latex, another title has been used in the published versio

Methionine derivatives as green corrosion inhibitors: Review

This review exposed the inhibitory effect of methionine as green compound and its derivatives. The efficacy of these kind of molecules is related to two combined groups: amine and carboxylic acid as well as the presence of sulphur atom. Search on Scopus showed that a hundred publications in various aggressive solutions as HCl, H2SO4, H3PO4, HNO3, NaCl. The corrosion of iron, aluminium, lead, copper, nickel, tin … can be retarded using methionine derivatives which adsorbed on several kind of adsorption isotherms depending on the nature of metal/solution interface

Overall Migration of the High Density Polyethylene in Bags used for carrying Hot Breads in the Traditional Bakeries

The main objective of this study to identify the effects of the temperature for the high density polyethylene (HDPE) used for carrying hot breads in the traditional bakeries (17 bakeries). From the results of the experimental analysis we found plastic components migration from the three types of the HDPE in the both simulants, distilled water and 3% of Acetic acid, at 70ᵒC and 100ᵒC of temperature. The obtained results concerning types A, B and C plastic bags in the distilled water simulant at 70ᵒC were 0.40, 0.90 and 2.60, thus at 100ᵒC were 0.60, 1.10 and 2.90 respectively .On the other hand, the obtained data for 3% of acetic acid at 70ᵒC were 0.80, 29.90 and 59.20, also at 100ᵒC were 0.90, 54.60 and 116 respectively. If we compared the obtained results between the two simulants we could mention that, there is significant relationship. We could confirm that there are significant relationships between the distilled water simulant and the 3% of Acetic acid simulant at both temperatures (70 and 100 ᵒC). The big deferent between A, B and C bags in the 3% of acetic acid concern the color of the bags

Corrosion inhibition of carbon steel in acidic medium by Grapefruit oil extract

Carbon steel is widely used in various fields such as the field of agri-food their use in tins and materials used in the food producing seen this material and susceptible to corrosion phenomena are in their environmental which produces toxic compounds in the environmental medium of this material. To this end we investigated in this direction by study of the inhibition of the phenomenon of corrosion of this material. Grapefruit oil extract (GO) was tested as corrosion inhibitor for mild steel in 1M HCl. Electrochemical impedance spectroscopy (EIS) method are used. The inhibiting action increases with the concentration of the tested inhibitor. The highest efficiency 86.15% is obtained at 1g/L of GO. Effect of temperature is also studied between 298 K and 328 K; GO presents best inhibition efficiency even at elevated temperature, GO is adsorbed on the steel surface according to a Langmuir isotherm adsorption model. The thermodynamic data of activation are determined. In this study fatty acid composition contents of Grapefruit were determined. The used methods indicate that the Grapefruit oil extract is a good inhibitor in 1.0 M HCl. Some thermodynamic functions of the carbon steel dissolution process in acid medium were also determined and discussed

Electrochemical and thermodynamic study of the inhibitory efficacy of Methanol extracts of the Rind and Leaves of Grapefruit plant on the corrosion of carbon steel in an acidic medium

The inhibition potentials of methanol extracts of leaves (GFL) and rind (GFR) of Grapefruit plant was investigated by evaluating the corrosion behaviour of carbon steel metal immersed in 1.0 M HCl solution containing various concentrations of the extracts. Electrochemical technical, Gravimetric measurements and adsorption characterization were utilized to evaluate the corrosion inhibition and adsorption properties of the extracts. The results revealed that the studied extracts were efficient inhibitors of corrosion in carbon steel immersed in 1.0 M HCl and that the inhibition efficiency depends on the concentration of the extracts. The activation energies and the negative free energy of adsorption obtained from the adsorption of methanol extracts of leaves and rind of Grapefruit indicate that the methanol extracts were physically adsorbed on the surface of the carbon steel and that the adsorption is endothermic, spontaneous, strong and fit excellently with the assumptions of the Langmuir adsorption isotherm. The activation parameters are determined and discussed. 

Experimental and theoretical investigation of 4-Methyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one on the corrosion and inhibition behavior of steel in acidic solution

The effect of 4-methyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one (MDBO) on the inhibition of steel corrosion was studied in an acid medium. This inhibiting action against corrosion of steel in a corrosive solution was studied at 298 K using potentiodynamic polarization curves, weight loss measurements and electrochemical impedance spectroscopy (EIS) and complementary with density functional theory (DFT) methods. The inhibiting action increases with the concentration of (MDBO) compound to attain 89.53% at 10-3 M. Polarization measurements also show that the 4-methyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one (MDBO) acts essentially as a mixte type inhibitor. The cathodic curves indicate that the reduction of proton at the steel surface happens with an activating mechanism. (MDBO) adsorbs on the steel surface according to Langmuir adsorption model. Effect of temperature is also made in the 298–328 K range. Activation parameters are determined and discussed. For establish the correlation between experimental data and theoretical results, some quantum chemical parameters for the tested compound were evaluated for supply more idea on the mechanism of inhibition of the dissolution process