Optimization of the inhibition corrosion of carbon steel in an acidic medium by a novel eco-friendly inhibitor Asphodelus ramosus using response surface methodology

Ethyl acetate extract of Asphodelus ramosus (ARAE) was examined as an anti-corrosion agent for carbon steel (CS) in 1 M HCl acid medium using different techniques, namely weight loss method, potentiodynamic polarization, and electrochemical impedance spec­troscopy (EIS) at various temperatures and inhibitor concentrations. An inhibition efficiency of 89.81 % was obtained by the weight loss method at the inhibitor concentration of 700 ppm at 293 K. Increasing the temperature decreases the corrosion inhibition rate. Poten­tiodynamic polarization results showed that the extract is adsorbed on CS surface according to the Freundlich isotherm, while negative values of the standard free energy of adsorption (DG0ads) suggested the physical spontaneity of the adsorption reaction. Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analyses were performed to examine the surface morphology of inhibited and uninhibited CS samples. Central composite design (CCD) based optimization was engaged to analyze factors and maximize inhibition efficiency by applying response surface methodology (RSM) using Design-Expert software

Field-induced spin density wave in (TMTSF)2_2NO3_3

Interlayer magnetoresistance of the Bechgaard salt (TMTSF)$_2$NO$_3$ is investigated up to 50 teslas under pressures of a few kilobars. This compound, the Fermi surface of which is quasi two-dimensional at low temperature, is a semi metal under pressure. Nevertheless, a field-induced spin density wave is evidenced at 8.5 kbar above $\sim$ 20 T. This state is characterized by a drastically different spectrum of the quantum oscillations compared to the low pressure spin density wave state.Comment: to be published in Phys. Rev. B 71 (2005

Synthèse de TTF et BI-TTF à ligands azotes, précurseurs potentiels de sels à propriétés électriques et magnétiques (Etude préliminaire des matériaux résultants)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Preparations and characterizations of new series of TTF ligands containing a nitrogen aromatic heterocycle

International audienceThe detailed synthesis of a new series of conjugated TTF ligands with nitrogen-based aromatic heterocycle are presented. In all these molecules, trimethyl-TTF or TTF skeleton are bridged to the nitrogen aromatic ligand through a conjugated spacer such as ethenyl or phenylethenyl unit. Their electrochemical characterization as well as the crystal structure of one of these compounds is given