The influence of the ferritic and austenitic phases and of silicon on the Corrosion resistance of alloyed cast steels

The paper deals with the influence of the α/gamma; phase ratio and silicon on the corrosion resistance of low carbon alloyed cast steels in strongly oxidizing media. Electrochemical investigations in 65% HNO₃ + 5g Cr⁶⁺ ions/I showed that none of the four tested cast steels, with γ_R = 100%, γ_R = 75%, γ_R = 50% and γ_R = 0%, achieved a passive state, and that the corrosion process was under cathodic control. Under such conditions the calhodic activation overpotential is considerably greater than the anodic activation overpotential, and, as well as this, the Tafel coefficient for a cathodic reaction has higher values than those which are characteristic for an anodic reaction. The austenitic cast steel is the most resistant to corrosion, since for the corrosion process to take place the greatest activation energy is needed. The results of investigations of corrosion resistance in 12M HNO₃, at 115°C, for 240 hours, confirmed the results of the electrochemical measurements and the predominant role of the austenitic cast steel with γ_R = 100%. By means of AES analysis it was found that the good resistance to corrosion of such a cast steel is based on the building up of a thin mechanically-protecting barrier, which mainly consists of silicon.     

Construction of a parallel computational model by composition of computational facilities

We consider a general algorithm for constructing a parallel numerical model by composition of several computational objects. The only requirement for the applicability of the proposed algorithm is for the disturbance propagation speed to be finite. We present one possible approach to map a numerical model onto an object-oriented program model. Some results of numerical experiments on solving the heat conduction equation in linear and nonlinear cases are discussed.     

Calculation of Settlers for Irrigation Systems

Power Technology and Engineering - This article describes a new method for calculating settlers for irrigation systems. The proposed method is based on the results of experimental research and...     

High-Speed Semiconductor Voltage Regulators for On-Load Distribution Network Transformers

Power Technology and Engineering - The paper presents the results of developing a high-speed semiconductor transformer voltage regulator (STVR) intended for a real-time voltage regulation of 0.4 kV...     

Robust Stability Conditions for a Family of Linear Discrete-Time Systems Subjected to Uncertainties

Automation and Remote Control - Robust stability conditions are established for a family of linear discrete-time systems subjected to uncertainties. The traditional approach, which involves the...     

Multidimensional Model of Opinion Dynamics in Social Networks: Polarization Indices

Automation and Remote Control - We consider a multidimensional model of opinion dynamics in social networks. Within the framework of the model, the dynamics of two interconnected information...