Zdravko Praunseis

Determination of the titanium corrosion resistance by nitrogenion implantation for applications in electrical engineering

Titanium and alloys are often used in modern electrical engineering. The aim of investigation was to optimize the conditions of nitrogenion implantation for commercially pure (CP) titanium and to correlate the implantation parameters with the corrosion resistance. Argonand oxygenion implantations were carried out to compare the corrosion resistance with nitrogen-ion implantation and to understand whether the increased corrosion associated with the nitrogen-ion implantation is a chemical effect produced by the nitrogen or a microstructure change produced by the ion implantation. A surface analysis using Grazing-Incidence X-ray Diffraction (GIXD) was carried out to further understand the role of nitrogen in the corrosion resistance of titanium in the simulated acid fluid. The results of the present investigation indicated that nitrogen-ion implantation can be used as a viable method for improving the corrosion resistance of titanium. Streszczenie. Tytan I jego stopy są często wykorzystywane w nowoczesnej elektrotechnice. Celem tej pracy jest optymalizacja warunków implantacji jonów azotu na komercyjnie czystym tytanie oraz skorelowanie parametrów implantacji z odpornością na korozję. Przeprowadzono implantacje jonów argonu I tlenu w celu porównania odporności korozyjnej z przypadkiem implantacji jonów azotu i uzyskania zrozumienia czy zwiększenie korozji z implanowanymi jonami azotu wynika z efektu chemicznego azotu czy też ze zmiany mikrostruktury spowodowanej implantacją jonów azotu. Analiza powierzchniowa przeprowadzona metodą GIXD (Grazing-Incidence X-ray Diffraction) pozwoliłą wyjaśnić wpływ azotu w na odporność korozyjną tytanu w symulowanym płynie kwasowym. Wyniki przedstawionych badań pokazują, że implantacja jonów azotu jest użyteczną metodą poprawy odporności korozyjnej tytanu. (Określanie odporności korozji tytanu poprzez implantacje jonów azotowych w zastosowaniach elektrotechnicznych).

Underground coal gasification - the Velenje coal mine energy and economic calculations

Underground coal gasification (UCG) is a viable possibility for the exploitation of vast coal deposits that are unreachable by conventional mining and can meet the energy, economic and environmental demands of the 21st century. Due to the complexity of the process, and the site-specific coal and seam properties, it is important to acknowledge all the available data and past experiences, in order to conduct a successful UCG operation. Slovenia has huge unmined reserves of coal, and therefore offers the possibility of an alternative use of this domestic primary energy source. According to the available underground coal gasification technology, the energy and economic assessment for the exploitation of coal to generate electricity and heat was made. A new procedure for the estimation of the energy efficiency of the coal gasification process, which is also used to compare the energy analyses for different examples of coal exploitation, was proposed, as well as the technological schemes and plant operating mode in Velenje, and the use of produced synthetic coal gas (syngas). The proposed location for the pilot demonstration experiment in Velenje Coal Mine was reviewed and the viability of the underground coal gasification project in Velenje was determined.

Comparison of the efficiency of drives with different energy sources for small city buses

This article describes a comparison of city buses with different powered drives (diesel and electric). The comparison is made on the case of the Municipality of Velenje which has a free public transport. Depending on current prices of energy sources the efficiencies of drives are compared, the purchase price of new vehicles and the cost of operating leasing of buses.