The application features of the modified graphitized carbon lining materials in the alumina electrolysis cell

It was studied how Sodium penetrates inside the samples of the Lithium-modified graphitized carbon material (GCM). The Sodium diffusion coefficients were defined after the GCM's treatment by the Lithium vapor and the diffusion activation energy was calculated for different conditions. The obtained kinetic dependencies allowed to establish the mechanism of Sodium diffusion into the modified GCM. It was shown to be reasonable to expose the GCM's samples to the preliminary treatment by the Lithium vapor which prevents the destruction of the alumina electrolysis cells' cathode surface's lining layers and thus increases its service life. As the tested GCM's samples demonstrated, the possibility was achieved to develop the protection technology of the bottom surface of the Sodium penetration in course of the electrolysis in the alumina-cryolite melts.

Performance evaluation of Cryo Laser Phoresis technique as biophysical method to promote diclofenac sodium cutaneous perfusion

ABSTRACT Aiming to alter and/or improve permeation of active compounds in the skin, many strategies have been developed, including biophysical methods. One of the physical absorption techniques, currently known as Cryo Laser Phoresis (CLP), consists of an apparatus that emits radiation on polar or nonpolar molecules of the active substance, resulting in faster penetration when in comparison to the standard topical application. The goal of this work was to evaluate the efficacy of a method that proposes to increase cutaneous permeation of diclofenac sodium by using CLP technique. The influence on permeation was evaluated ex vivo, using Franz cell and human skin obtained from cosmetic surgery. The results were evaluated using statistical methods and data exploratory analysis: clusters, k-means and Principal Component Analysis. The results showed a larger increase in the concentration of diclofenac sodium in the dermis with the use of laser. In all samples (with or without laser application) it was observed that skin surface showed an amount of diclofenac sodium and that there was no active passage to the receptor liquid, suggesting that diclofenac sodium was not absorbed. These results indicate that CLP, when used under the conditions described in this study, is able to increase diclofenac sodium penetration and its retention into deeper layers.

Role of Microstructure on Fracture Behavior of T91 Steel in Presence of Liquid Sodium

The sensitivity to liquid sodium embrittlement (LME) of T91 martensitic steel, one of the selected structural materials for future sodium fast reactors has been investigated. The study took into account the role of microstructure. Small punch tests and three points bending tests were carried out in a purified and controlled atmosphere. Precipitation state and dislocations structure resulting from a tempering at 550° C provoked LME of the T91 steel between 200 and 550 °C. Secondary Ions Mass Spectroscopy investigation suggested that sodium penetration at prior austenitic grains boundaries promoted by plastic deformation occurred and caused brittle crack initiation. Brittle cracks propagated in sodium preferentially along martensitic laths-boundaries. J integral calculations confirmed a drop in toughness of T91 tempered at 550°C by liquid sodium up to 80 %.

Experimental Research and Numerical Simulation Analysis of Sodium Expansion in Tib2-Carbon Cathodes during Aluminum Electrolysis

Experimental investigation of sodium expansion in TiB2-carbon with different TiB2 content during aluminum electrolysis was carried out in a laboratory cell. The model based on the swelling due to the sodium penetration has been discussed, and relationship between the sodium expansion and time has been proposed that has been calculated by MATLAB. The proposed model was extended to the three-dimensional distribution of sodium concentration, stress and first principal stress that was implemented by ANSYS. Validation of this numerical tool was achieved through the Rapoport tests. The results show good agreement between analytical solution and numerical modeling as well as between experimental and numerical results. This means that the chosen numerical model is suitable to predict sodium expansion as well as induced stresses in TiB2-carbon cathodes and is great interest in the work to extend aluminum reduction cell lifetime.