Jozef Zajac

Prof. Jozef Zajac


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 March 2017 in Materials
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Journal Article
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APAnton Panda
Anton Panda
KDKostiantyn Dyadyura
Kostiantyn Dyadyura
JVJan Valíček
Jan Valíček
Marta HarničárováMarta Harničárová
Marta Harničárová
JZJozef Zajac
Jozef Zajac
ZPZdeněk Pavelek
Zdeněk Pavelek
The results of the investigations into the technological formation of new wear-resistant polymer composites based on polytetrafluoroethylene (PTFE) filled with disperse synthetic and natural compounds are presented. The efficiency of using PTFE composites reinforced with carbon fibers depends on many factors, which influence the significant improvement of physicomechanical characteristics. The results of this research allow stating that interfacial and surface phenomena of the polymer–solid interface and composition play a decisive role in PTFE composites properties. Fillers hinder the relative movement of the PTFE molecules past one another and, in this way, reduce creep or deformation of the parts, reducing the wear rate of parts used in dynamic applications as well as the coefficient of thermal expansion. The necessary structural parameters of such polymer composites are provided by regimes of process equipment.

17 November 2016 in The International Journal of Advanced Manufacturing Technology
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Journal Article
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Vitalii IvanovVitalii Ivanov
Vitalii Ivanov
DMDusan Mital
Dusan Mital
VKVladyslav Karpus
Vladyslav Karpus
IDIvan Dehtiarov
Ivan Dehtiarov
JZJozef Zajac
Jozef Zajac
MHMichal Hatala
Michal Hatala

3 November 2015 in Materials
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Journal Article
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JVJan Valíček
Jan Valíček
Marta HarničárováMarta Harničárová
Marta Harničárová
AÖAndreas Öchsner
Andreas Öchsner
ZHZuzana Hutyrová
Zuzana Hutyrová
MKMilena Kušnerová
Milena Kušnerová
JZJozef Zajac
Jozef Zajac
The paper solves the problem of the nonexistence of a new method for calculation of dynamics of stress-deformation states of deformation tool-material systems including the construction of stress-strain diagrams. The presented solution focuses on explaining the mechanical behavior of materials after cutting by abrasive waterjet technology (AWJ), especially from the point of view of generated surface topography. AWJ is a flexible tool accurately responding to the mechanical resistance of the material according to the accurately determined shape and roughness of machined surfaces. From the surface topography, it is possible to resolve the transition from ideally elastic to quasi-elastic and plastic stress-strain states. For detecting the surface structure, an optical profilometer was used. Based on the analysis of experimental measurements and the results of analytical studies, a mathematical-physical model was created and an exact method of acquiring the equivalents of mechanical parameters from the topography of surfaces generated by abrasive waterjet cutting and external stress in general was determined. The results of the new approach to the construction of stress-strain diagrams are presented. The calculated values agreed very well with those obtained by a certified laboratory VÚHŽ.

1 January 2012
Verified
Book Chapter
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PMPeter Michalik
Peter Michalik
JZJozef Zajac
Jozef Zajac
Ján DuplákJán Duplák
Ján Duplák
APAlexander Pivovarnik
Alexander Pivovarnik

6 July 2020 in Processes
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JZJozef Zajac
Jozef Zajac
Ján DuplákJán Duplák
Ján Duplák
Darina DuplákováDarina Dupláková
Darina Dupláková
PCPeter Cizmar
Peter Cizmar
IOIgor Olexa
Igor Olexa
ABAnton Bittner
Anton Bittner
This article is focused on the prediction of cutting material durability by Taylor’s model. To create predictive models of the durability of cutting materials in the turning process, tools made of high-speed steel, sintered carbide without coating and with Titanium nitride (TiN) coating, cutting ceramics without coating and with TiN coating were applied. The experimental part was performed on reference material C45 using conventional lathe—type of machine SU50A and computer numerical control machine—CNC lathe Leadwell T-5 in accordance with International Organization for Standardization—ISO 3685. Implementation of the least-squares method and processing of regression analysis made predictions of cutting tool behaviour in the turning process. Using the method of regression analysis, a correlation index of 93.5% was obtained, indicating the functional dependence of the predicted relationship.

1 August 2013 in Advanced Science Letters
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Journal Article
Closed access
APAnton Panda
Anton Panda
JDJán Duplák
Ján Duplák
Jozef JurkoJozef Jurko
Jozef Jurko
JZJozef Zajac
Jozef Zajac