Vojnotehnicki glasnik / Military Technical Courier

397-405

Authors: Ristić Zoran, Ilić Slobodan, Kari Aleksandar

Friction and wear model of rotating band, due to, heating and melting material between the contact surface of a bore and projectile is described in this paper. The hydrodynamic slider-bearing model of the metal rotating band is applied and the Reynold's equation for the "fluid" (melting film) has been used in this work. The fluid temperature was assumed to be constant and equal to the melting temperature on the contact surface. Based on the total heat transfer from the film, which is made, between the melting on the non-melting surface (Landan model) and certain results of the film thickness, the coefficient of melt friction and the material wear were achieve. The size wears of the projectile rotating band and influence of certain parameters on the friction force and the film thickness are given in this paper. The achieved results have been illustrated by chosen example.

418-429

Authors: Veselinović Saša, Milenković Srđan

Available maintenance information system in the military forces is, with some modification, retained from the period after the World War П. There were several attempts of automatization of maintenance information systems, but all the attempts failed, whether because of the wrong approach or the wrong choice of program tools. A reform in military forces has got an important influence on organization of maintenance system, but the influence on the maintenance information system is minor. The first step in automatization is detailed analysis of processes and the dataflow that should be automated. For successful automatization, the analysis and process description ND dataflow should be made in some of the modern systems for information systems production. The model of maintenance information system, described with 19 sub-processes, offers one of the many possible ways for automatization, which is verified through the program "Automatization informational system of maintenance - troop level". If system of national defence wants to enter the international integrations, it must have compatible information systems that can be made, bought or imposed by the international organizations.

442-450

Authors: Grbović Luka, Stoiljković Slaviša

Monitoring the content of the stabilizer is one of the most reliable and modern methods used all over the world as well as in our country for chemical stability control and shelf life prediction of gun powders. For reliability rating of the used method, there has been examined samples of naturally aged single-based gun powder NC type and double-based gun powder NGB type all manufactured in different years. The samples were taken from explosive ordnance. Reaction rates constants of stabilizer consumption and shelf life of gun powders have been determined. These values were compared to analog results taken for the same gun powders tested 20 years ago. Satisfactory agreement either for naturally or accelerating aging gun powders has been confirmed. Beside that, it was determined that NC gun powder from non hermetic munitions cases proved to be considerably less stable than the originally packed NC gun powder.

461-471

Authors: Konjević Mitar

Hydrogen represents the ecologically clean and practically inexhaustible energetic element, relatively easy for storage, transportation and exploitation. Nevertheless, due to high price of its production, hydrogen has not yet been a competition to actual fossil fuels. If we suppose that hydrogen will be pretty important vector in future, it is interesting to show the exploitation possibilities of hydrogen informs of hydrides and fuel cells.