In this paper an attempt to determine the relationship between the electrical resistivity and the tensile strength and hardness of cast iron of

carbon equivalent in the range from 3.93% to 4.48%. Tests were performed on the gray cast iron for 12 different melts with different

chemical composition. From one melt poured 6 samples. Based on the study of mechanical and electro-resistive determined variation

characteristics of tensile strength, hardness and resistivity as a function of the carbon equivalent. Then, regression equations were

developed as power functions describing the relationship between the resistivity of castings and their tensile strength and hardness. It was

found a high level of regression equations to measuring points, particularly with regard to the relationship Rm=f(ρ). The obtained

preliminary results indicate the possibility of application of the method of the resistance to rapid diagnostic casts on the production line,

when we are dealing with repeatable production, in this case non variable geometry of the product for which it has been determinated

before a regression equation.

The publication presents the results of examination of selected carburizers used for cast iron production with respect to their electric

resistance. Both the synthetic graphite carburizers and petroleum coke (petcoke) carburizers of various chemical composition were

compared. The relationships between electrical resistance of tested carburizers and their quality were found. The graphite carburizers

exhibited much better conductivity than the petcoke ones. Resistance characteristics were different for the different types of carburizers.

The measurements were performed according to the authors’ own method based on recording the electric current flow through the

compressed samples. The samples of the specified diameter were put under pressure of the gradually increased value (10, 20, 50, 60, and

finally 70 bar), each time the corresponding value of electric resistance being measured with a gauge of high accuracy, equal to 0.1μΩ.

The higher pressure values resulted in the lower values of resistance. The relation between both the thermal conductance and the electrical

conductance (or the resistance) is well known and mentioned in the professional literature. The results were analysed and presented both in

tabular and, additionally, in graphic form.

The propagation of EEG activity during the Continuous Attention Test (CAT) was determined by means of Short-time Directed Transfer Function (SDTF). SDTF supplied the information on the direction, spectral content and time evolution of the propagating EEG activity. The differences in propagation for target and non-target conditions were found mainly in the frontal structures of the brain.