Effect of some organic additives on the corrosion behaviour of Cu-Fe and Cu-Al - Fe alloys in sulphuric acid solution

The effect of some organic compounds on the corrosion corr behavior of copper - iron alloy [1] and copper - aluminium - iron alloy [II] in 0.5 M H[2]SO[4] aqueous solution was investigated. The techniques of measurements were: weight loss, linear polarization and impedance spectroscopy. The organic compounds were: glycine [I], alanine [II], valine [III], histidine [IV], 2- aminothiazole [V] and 3- methyl -1- phenyl -2- pyrazolin -5- one [VI]. These compounds have high inhibition efficiency increases according to the order: I < II < III < IV < VI < V. The inhibitory effect of these compounds is achieved by their adsorption on the metallic surface via adsorption centers [N - atom and / or S- atom]. Their adsorption the metallic surface follows Temkins' isotherm of adsorption. The values of standard free energy of adsorption, delta G[degree sign] [ads], were calculated from the adsorption isotherms. The negative values of delta G[degree sign] [ads] indicate the adsorption process occurs spontaneously. There is an agreement between the results obtained from the different techniques of measurements

Extraction and carrier-facilitated transport of amino acids using synthetic non-cyclic receptors through bulk liquid membrane.

The extraction and carrier-facilitated transport of amino acids (leucine, valine and glycine) was studied through chloroform bulk liquid membrane system using a series of non-cyclic receptors such as diethylene glycol (1), diethylene glycol dimethyl ether (2), diethylene glycol dibutyl ether (3), diethylene glycol dibenzoate (4), triethylene glycol (5) and tetraethylene glycol (6). The amount of amino acid extracted and transported depends mainly upon the structure and the concentration of the receptors and also on the concentration of amino acid. The receptors 1 to 4, having small chain length and flexible end groups, formed stable complexes with amino acids, and the flexibility of receptors in different conformational forms was responsible for their carrier ability, while the receptors 5 and 6, having larger chain length showed poor carrier ability. Hydrophobicity of amino acids also play an important role in the extraction as well as transport process.

Dielectric relaxation study of glycine and valine in water mixture using picosecond time domain reflectometry.

The complex permittivity of glycine and valine in water mixture for various temperatures and concentrations have been measured as a function of frequency between 10 MHz and 10 GHz using (TDR) time domain reflectometry technique. Dielectric parameters ie. static dielectric constant and relaxation time were obtained from the complex permittivity spectra using nonlinear least square fit method. From the values of relaxation time, thermodynamic parameters were determined.