Study of Steel Electro-dissolution Behavior in Presence of Some Surfactants. Electrochemical Investigation and Surface Active Properties Determination

Steel electro-dissolution performance was investigated in orthophosphoric acid in the presence of N-oleyl 1.3 diaminopropane, Benzalkounuim chloride, Soduim lauryl sulphate and Di-Isononyl phthalate as a surfactant using potentiodynamic polarization measurements. The retardation performance of these surfactants was examined. The surfactant surface active parameters were estimated based on surface tension measurements. The parameters calculated comprise the critical micelle concentration (CMC), maximum surface excess (Гmax), minimum surface area (Amin) and effectiveness (πCMC). The micellization thermodynamic parameters (ΔGmic, ΔSmic) for the estimated surfactants were also computed. Results obtained from surface active properties are comparable with those gained from galvanostatic polarization measurements. Temperature influence on the steel dissolution performance was examined at 25 to 40oC range. Steel kinetic study in orthophosphoric acid- free solution and orthophosphoric acid containing surfactant was also examined. The dissolution kinetic and activated parameters were computed. Results based on microscopy measurement indicate that, addition of new four surfactants, resulting in the solution shows potential, a discrete progress in the metal texture was monitored. Improvement produced in electro-polishing bath by the investigated SAS that owing to the adsorption of such surface active agents on the anode surface.

Testing of Carbon Nanotubes and their Influence on the Physical and Mechanical Characteristics of Polyester Resin

Carbon nanotubes have been studied by scanning electron microscopy. Measurement modes - accelerating voltage 10 kV, current in microscopy mode 10-9 A. The sample was applied to a metal mesh. Spectroscopic data indicate that this sample consists of carbon (peak at 280 eV). There are no other intense peaks in the spectrum; no impurities were detected by this method. Determination of physical and mechanical characteristics was carried out on a testing machine model N5K-S.

Newly Isolated Animal Pathogen Corynebacterium silvaticum Is Cytotoxic to Human Epithelial Cells

Corynebacterium silvaticum is a newly identified animal pathogen of forest animals such as roe deer and wild boars. The species is closely related to the emerging human pathogen Corynebacterium ulcerans and the widely distributed animal pathogen Corynebacterium pseudotuberculosis. In this study, Corynebacterium silvaticum strain W25 was characterized with respect to its interaction with human cell lines. Microscopy, measurement of transepithelial electric resistance and cytotoxicity assays revealed detrimental effects of C. silvaticum to different human epithelial cell lines and to an invertebrate animal model, Galleria mellonella larvae, comparable to diphtheria toxin-secreting C. ulcerans. Furthermore, the results obtained may indicate a considerable zoonotic potential of this newly identified species.