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  • Fundamentals of Electrical Engineering x
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G. Preduşcă and C. Fluieraru

Abstract

If the electrons and holes in excess are created in a semiconductor, either by means of light absorption, or using other methods, the thermic balance is disturbed, therefore these electrons and holes should be nullified after the source had been stopped. This process is named recombination. There are three main recombination types: radioactive, Auger and deep energy level recombination. All three are based on the doping concentration to a certain point. The life time is determined using the three recombination processes in semiconductor.

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D. Puiu, B. Corbescu and C. Cepisca

Abstract

The power cables passing through penetration leads to growth of the thermal ageing mechanisms rate. The paper presents the results of the laboratory tests when the real environmental service conditions for penetration are simulated comparison with the result of the thermal computation of the power cables heating and of the temperature influence evaluation of temperature increase of the power cable components on the cable lifetime. For this particular case, a power cable with PVC insulation, we estimated a lifetime decrease about 20 years referring to lifetime (30÷40 years) for location in air.

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P. Zielinski

2004. 19. Program komputerowy Statgraphics Plus v. 5.1, A Manugistics Inc. Product, Rockville, MD USA, 2000, Nr 537672031051732. 20. M. Dobosz, Computer aided statistical analysis of research results [in Polish], Problemy współczesnej nauki, Teoria i zastosowania, STATYSTYKA, AOW EXIT, Warszawa, 2001. 21. M. Tazl, M. Meyer, Lifetime extension of reconstructed asphalt pavements by using geosynthetic interlayers: effectiveness of an innovative combined system, Proceedings of the 9th International Conference on

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P. Zieliński

, Lifetime extension of reconstructed asphalt pavements by using geosynthetic interlayers: effectiveness of an innovative combined system, Proceedings of the 9th International Conference on Geosynthetics, Brazil, 2010, pp. 1496-1498 15. P. Zieliński, Investigations of geosynthetic interlayer bonding in asphalt layers, Archives of Civil Engineering, 4/2011. 16. P. Zieliński at al., Research project Nr 5.TO7 E.070.25, Geosynthetic bonding of interlayer on fatigue life of bitumen pavement construction.[in Polish]. 2003-2004. 17

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L. Petrescu, E. Cazacu, V. Ioniţă and Maria-Cătălina Petrescu

Abstract

Electrical transformers are essential parts of power supply networks and it is important that their life-time to be preserved. The inrush current of this devices could determine malfunctioning of the transformers or even others component of the network. For this reason, determining the inrush current for single-phase transformers is an important issue in power quality analysis of electrical grids. In this paper we presented an experimental device (hardware set-up and software program) that can measure this in rush current features for small transformers (up to 10 kVA). Also, the device affords the users to measure inrush current knowing the geometry of the transformer, the dimensions and the magnetic characteristic of the core.

Open access

Balázs Kósa, Hajnalka Juhász, Lilla Gyüre, Olivér Schmidt, Renáta Németh-Szigeti, Kinga Paczolai and Attila Béla Széll

Abstract

Hungary has been the home of many peoples from the beginnings of its history. As a result, our accumulated heritage is made up of buildings which were built, used and formed by different peoples during their lifetimes. This study investigates the diversity of the built heritage, the architectural and social multiculturalism in the city centre of Pécs.