Browsing by Author "Wiktor, Tomasz"

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Access status: Open Access ,
An evaluation of combustion kinetics for the synthesis reaction of the reinforcing phase during casting
(AGH University of Science and Technology Press, 2020) Wiktor, Tomasz; Sobula, Sebastian; Burbelko, Andriy A.; Ptasznik, Michał
The computer modeling of the solidification process in castings with local composite reinforcement (LCR) obtained as a result of in situ reactions of self-propagating high temperature synthesis (SHS) is difficult due to limited data on the thermo-physical parameters of exothermic effects and the kinetics of the synthesis reaction. In the present study, Hadfield cast steel casting was manufactured with LCR containing titanium carbide particles obtained in situ by the SHS method. Reaction kinetics of titanium carbide synthesis in the composite casting were determined on the basis of temperature measurements in the area of LCR during the process. For the estimation of the reaction, the Fourier Thermal Analysis method was used. The paper presents the results of temperature measurement and the results of the calculation of SHS reaction kinetics. It was found that the reaction time under the conditions of the analyzed casting is below 3 s.
Access status: Open Access ,
Derivation of equations for a size distribution of spherical particles in non-transparent materials
(AGH University of Science and Technology Press, 2021) Gurgul, Daniel; Burbelko, Andriy A.; Wiktor, Tomasz
This paper presents a new proposition on how to derive mathematical formulas that describe an unknown Probability Density Function (PDF$_{3}$) of the spherical radii ($r_{3}$) of particles randomly placed in non-transparent materials. We have presented two attempts here, both of which are based on data collected from a random planar cross-section passed through space containing three-dimensional nodules. The first attempt uses a Probability Density Function (PDF$_{2}$) the form of which is experimentally obtained on the basis of a set containing two-dimensional radii ($r_{2}$). These radii are produced by an intersection of the space by a random plane. In turn, the second solution also uses an experimentally obtained Probability Density Function (PDF$_{1}$). But the form of PDF$_{1}$ has been created on the basis of a set containing chord lengths collected from a cross-section. The most important finding presented in this paper is the conclusion that if the PDF$_{1}$ has proportional scopes, the PDF$_{3}$ must have a constant value in these scopes. This fact allows stating that there are no nodules in the sample space that have particular radii belonging to the proportional ranges the PDF1.