https://dspace.upt.ro/xmlui/handle/123456789/4 2026-09-12T20:43:58Z 2026-09-12T20:43:58Z Țigan, Gheorghe Cismaș, Emanuel Mihalaș, Stelian Brandibur, Oana https://dspace.upt.ro/xmlui/handle/123456789/9439 2026-09-10T06:41:05Z 2019-01-01T00:00:00Z

On the normal form of double–Hopf bifurcation [articol] Țigan, Gheorghe; Cismaș, Emanuel; Mihalaș, Stelian; Brandibur, Oana A study on degenerate normal form of double-Hopf bifurcation is performed. This bifurcation is met in differential systems of dimension at least four and with minimum two independent parameters. We obtain bifurcation diagrams for amplitude system when one or two generic conditions are eliminated.

2019-01-01T00:00:00Z Stevanović, Dragan Janjić, Aleksandar Tasić, Dragan https://dspace.upt.ro/xmlui/handle/123456789/9438 2026-09-09T09:36:25Z 2019-01-01T00:00:00Z

Statistical analysis of minimum oil circuit breaker failures [articol] Stevanović, Dragan; Janjić, Aleksandar; Tasić, Dragan In this paper, remaining useful life (RUL) of circuit breakers (CB) has been analyzed, based on statistical data gathered during CB’s maintenance. Using statistical data of 427 CBs gathered in past 10 years, Weibull probability distribution of contact resistance for breakers on both overhead and underground feeders and voltage levels of 35 kV and 10 kV is determined. With this methodology CB’s condition can be observed by using real field data which are collected regullary during power station revision.

2019-01-01T00:00:00Z Koprivica, Branko Milovanović, Alenka Divac, Srdan Tatović, Mihajlo Plazinić, Milan Vujičić, Vojislav https://dspace.upt.ro/xmlui/handle/123456789/9437 2026-09-09T09:23:12Z 2019-01-01T00:00:00Z

Visualisation of static and stationary magnetic fields [articol] Koprivica, Branko; Milovanović, Alenka; Divac, Srdan; Tatović, Mihajlo; Plazinić, Milan; Vujičić, Vojislav The aim of this paper is to present a way of visualisation of the magnetic field created by permanent magnets or wires and loops carrying direct current. Visualisation is achieved by using so called magnetic field viewer - a special magnetic sensing film. Except visualisation of the magnetic field around the magnetic object, measurements of magnetic flux densities are performed using a Hall sensor. Also, a number of simulations of coils carrying direct current in FEM software have been made in order to check a validation of the visualisation effects obtained. The paper shows photographs of visualised magnetic fields and the results of measurements and simulations, as well as a proper discussion.

2019-01-01T00:00:00Z Cvetkovic, Zlata Mančić, Žaklina Ilić, Saša Petkovic, Bojana Potrebić, Milka https://dspace.upt.ro/xmlui/handle/123456789/9436 2026-09-10T07:36:37Z 2019-01-01T00:00:00Z

Effects of external dielectric body on plan-parallel system field homogeneity [articol] Cvetkovic, Zlata; Mančić, Žaklina; Ilić, Saša; Petkovic, Bojana; Potrebić, Milka In this paper, it is presented the influence of an external cylindrical dielectric body on the homogeneous electrostatic field. To obtain a homogeneous electrostatic field, a system of four charged parallel electrodes was installed on the imaginary cylindrical surface of the radius R (primary cell of the first order). Expressions for the field within and outside the external body are obtained using the Image theorem in cylindrical dielectric mirror. Special attention was dedicated to the 2D view of the field in the cross-section of the system.

2019-01-01T00:00:00Z