The determination of ductile fracture criteria as well as friction coefficient, stress-strain curves, constants for Hollomon's equation and a material workability based on analytical methods as a forming limit diagram, a normalized Cockcroft-Latham criteria (nCL)) ring and compression tests for two materials based on aluminum and copper alloys were carried out. A calculation of nCL criteria on the basis of a compression test and numerical simulations was made. The critical values nCL criteria resulting from compression test were determined. Prediction of nCL criteria by numerical simulations were confirmed by laboratory compression tests. The values obtained from numerical simulations and compression tests for both materials show a good coincidence in results.

The article deals with optimization of vehicle fleet size in a car-sharing system. The inventory theory (stochastic model) was applied to determine optimal vehicle fleet size under the assumption of implementation of carsharing system. The statistical characteristics for the model were acquired by random moment observation of real park place in Košice city. We can conclude that decrease of needed vehicles caused by implementation of such a system will be 56,60 % if we abstract from the cars commuting from the city surroundings.

The objective of this paper is the analysis of physical properties and microstructure of high speed steel powders produced vie gas atomization into gas and into water. We have found that the influence of atomization method on the physical properties and on the microstructure of high speed steel powder particles is considerable higher than that of their chemical composition. The increasing cooling rates resulted in microstructure changes and at a particular threshold cooling rate the crystallization mechanism qualitatively changes.

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