Title
Električni proboji u vazduhu: novi eksperimenti o statistički i numerički modeli : doktorska disertacija
Creator
Jovanović, Aleksandar P. 1984-
Copyright date
2014
Object Links
Select license
Autorstvo-Nekomercijalno-Bez prerade 3.0 Srbija (CC BY-NC-ND 3.0)
License description
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Language
Serbian
Cobiss-ID
Theses Type
PhD thesis
Other responsibilities
mentor
Marković, Vidosav 1960-
član komisije
Đurović, Stevica
član komisije
Popović, Biljana 1954-
član komisije
Stamenković, Suzana 1974-
član komisije
Šišović, Nikola
Academic Expertise
Prirodno-matematičke nauke
Academic Title
-
University
Univerzitet u Nišu
Faculty
Prirodno-matematički fakultet
Group
Odsek za fiziku
Title translated
ELECTRICAL BREAKDOWNS IN AIR: NEW EXPERIMENTS AND STATISTICAL AND NUMERICAL MODELS : PhD Thesis
Publisher
Niš : [A. P. Jovanović]
Format
PDF/A (147 listova)
description
Umnoženo za odbranu.
Univerzitet u Nišu, Prirodno-matematički fakultet, 2014.
Bibliografija: listovi 101-114.
Izvod ; Abstract.
description
Physics of ionised gases
Abstract (en)
Experimental work was carried out in laboratory for physics of
ionized gases and lasers in Faculty of Sciences and
Mathematics in Niš. Scanning electron microscopy and energy
dispersive X-ray spectroscopy of electrodes were carried out in
Faculty of Medicine in Niš, atomic force microscopy were
carried out in Institute of Physics in Belgrade and the
measurements on quantometer were carried out in AD “Kopex
MIN LIV”.
In this dissertation processes occurring before, during and after
the electrical breakdown in synthetic air are studied by
breakdown time delay measurements. Time delay distributions
at different conditions and with different electrodes are
measured, fitted by Gaussian, mixture Gauss-exponential and
exponential distributions and modeled by Monte Carlo
simulation. Mixture distributions are generalized and a relation
for the effective electron yield is derived. The occurrence of
mixture distributions is explained by an increased emissivity of
the cathode due to formation of the oxide at the cathode and
increased effective surface area. A new methods for
determination of the formative time delay, electron attachment
coefficient and the drift velocity of the dominant ions are
proposed. The memory curve at low pressure is analyzed and
three distinctive regions are observed. The first regions is
explained by the diffusion losses of the dominant ions. By
applying the analytical model the diffusion coefficients of the
dominant ions are determined. The two-dimensional numerical
model for early and late relaxation is developed. The onedimensional
model is used to calculate stationary glow number
densities of ions which are used as initial number densities for
modelling the relaxation. The results of numerical model
indicate that the dominant ion in the early relaxation is oxygen O+2 ions due to intensive
N+2 ion conversion. Late relaxationis explained by the surface recombination of nitrogen atoms on
borosilicate glass and stainless-steel electrodes. From the
numerical model the coefficients of nitrogen atom surface
recombination are determined.
Authors Key words
Fizika
Classification
621.38
Subject
53
Type
Elektronska teza
Abstract (en)
Experimental work was carried out in laboratory for physics of
ionized gases and lasers in Faculty of Sciences and
Mathematics in Niš. Scanning electron microscopy and energy
dispersive X-ray spectroscopy of electrodes were carried out in
Faculty of Medicine in Niš, atomic force microscopy were
carried out in Institute of Physics in Belgrade and the
measurements on quantometer were carried out in AD “Kopex
MIN LIV”.
In this dissertation processes occurring before, during and after
the electrical breakdown in synthetic air are studied by
breakdown time delay measurements. Time delay distributions
at different conditions and with different electrodes are
measured, fitted by Gaussian, mixture Gauss-exponential and
exponential distributions and modeled by Monte Carlo
simulation. Mixture distributions are generalized and a relation
for the effective electron yield is derived. The occurrence of
mixture distributions is explained by an increased emissivity of
the cathode due to formation of the oxide at the cathode and
increased effective surface area. A new methods for
determination of the formative time delay, electron attachment
coefficient and the drift velocity of the dominant ions are
proposed. The memory curve at low pressure is analyzed and
three distinctive regions are observed. The first regions is
explained by the diffusion losses of the dominant ions. By
applying the analytical model the diffusion coefficients of the
dominant ions are determined. The two-dimensional numerical
model for early and late relaxation is developed. The onedimensional
model is used to calculate stationary glow number
densities of ions which are used as initial number densities for
modelling the relaxation. The results of numerical model
indicate that the dominant ion in the early relaxation is oxygen O+2 ions due to intensive
N+2 ion conversion. Late relaxationis explained by the surface recombination of nitrogen atoms on
borosilicate glass and stainless-steel electrodes. From the
numerical model the coefficients of nitrogen atom surface
recombination are determined.
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