Vojnotehnicki glasnik / Military Technical Courier

15-39

Authors: Evseev Sergej Petrovič, Dorohov Aleksandr Vasiljevič, Korolj Olga Grigorevna

Protocols of information protection in computer networks and systems are investigated. The basic types of threats of infringement of the protection arising from the use of computer networks are classified. The basic mechanisms, services and variants of realization of cryptosystems for maintaining authentication, integrity and confidentiality of transmitted information are examined. Their advantages and drawbacks are described. Perspective directions of development of cryptographic transformations for the maintenance of information protection in computer networks and systems are defined and analyzed.

62-78

Authors: Vladisavljević Goran T.

Membrane emulsification is a process of injecting a pure dispersed phase or pre-emulsion through a microporous membrane into the continuous phase. As a result of the immiscibility of the two phases, droplets of the dispersed phase are formed at the outlets of membrane pores. The droplets formed in the process are removed from the membrane surface by applying cross-flow or stirring of the continuous phase or using a dynamic (rotating or vibrating) membrane. The most commonly used membrane for emulsification is the Shirasu Porous Glass (SPG) membrane, fabricated through spinodal decomposition in a melt consisting of Japanese volcanic ash (Shirasu), boric acid and calcium carbonate. Microsieve membranes are increasingly popular as an alternative to highly tortuous glass and ceramic membranes. Microsieves are usually fabricated from nickel by photolithography and electroplating or they can be manufactured from silicon nitride via Reactive Ion Etching (RIE). An advantage of microsieves compared to the SPG membrane is in much higher transmembrane fluxes and higher tolerance to fouling by the emulsion ingredients due to the existence of short, straight through pores. Unlike conventional emulsification devices such as high-pressure valve homogenisers and rotor-stator devices, membrane emulsification devices permit a precise control over the mean pore size over a wide range and during the process insignificant amount of energy is dissipated as heat. The drop size is primarily determined by the pore size, but it depends also on other parameters, such as membrane wettability, emulsion formulation, shear stress on the membrane surface, transmembrane pressure, etc.

93-115

Authors: Ilić Slaviša M., Andrejić Marko D.

This paper analyzes the effectiveness of possible models for queuing at gas stations, using a mathematical model of the large-scale queuing theory. Based on actual data collected and the statistical analysis of the expected intensity of vehicle arrivals and queuing at gas stations, the mathematical modeling of the real process of queuing was carried out and certain parameters quantified, in terms of perception of the weaknesses of the existing models and the possible benefits of an automated queuing model.

134-157

Authors: Perić Sreten R.

Nowadays, a special attention is focused on the development of modern devices and methods for monitoring condition changes of tribomehanical characteristics in systems. There are different physical and chemical methods and tribology methods for tribomehanical system diagnosis. Experience in technical systems exploitation showed that the most effective failure prognosis is based on particles created as a result of wear. The analysis of oil samples containing particles-products of wear, enables the evaluation of system tribology conditions in different phases of system exploitation. The paper presents the tribological tests in the analysis of oils used for the assessment of its condition. The paper also deals with the results of the experimental research of tribological characteristics of motor and power transmitter oils sampled from engines and power transmitters of the Mercedes O 345, PUCH 300GD and PINZGAUER 710M vehicles in exploitation. The investigations showed that there is a change of tribological characteristics of lubrication oils in the vehicle engine and power transmitters. These changes are in a direct dependence of the state of all elements of the tribomechanical engine and power transmitters system, and they depend on their functional characteristics. The conclusion is based on the realized testing.

174-193

Authors: Viličić Aleksandar B., Jezdimirović Mirko M.

This paper describes a simulation of a real electrical servo drive with a digital equalizer. The whole system is simulated in the simulation toolkit of the LabView package. Real transfer functions are simulated (the transfer functions of the motor and the current and angular velocity gauges), as well as the nonlinearities of the motor and the gears. Clasical mathematical methods for modeling servosistems are used. The method for determining transfer function parameters is also used. The influence of neglecting the electrical time constant is analyzed.

208-247

Authors: Paligorić Anastas L

The development of the NORA family started as far as back to 1976 at the Military Technical Institute of the Yugoslav's People's Army. The programme covered development of several types of the main artillery weapon: the 152 mm NORA-A towed gun-howitzer, the 152 mm NORA-B self-propelled gun-howitzer and the 152 mm gun-howitzer with APU. Under the same programme, the conversion of the Russian 130 mm towed gun M46 into the 155 mm M46/84 gun (for export needs) and the 152 mm M46/86 gun respectively (for the needs of the YPA) was completed. Only the 152 mm M84 (NORA-A) towed howitzer was introduced in service, while the development of the NORA-B and NORA-C weapons was carried on until 1992. After it had been suspended for many years, the development of the NORAB weapon was continued in 2003, followed by serial production of the 155 mm NORA-B52 self-propelled system for the export needs.

261-271

Authors: Borisov Mirko A., Branković Radoje D.

The article deals with some possibilities of presenting and visualising geospatial data. The Internet is especially useful for analyzing and detection of geospatial reality and its features. In the field of geodesy and cartography the use of the Internet is very impressive. Virtual atlases have become very attractive.

282-293

Authors: Stopić Srećko R.

The GDMB Society for Mining, Metallurgy, Resource and Environmental Technology organized the 6th European Metallurgical Conference (2011) in Duesseldorf from June 26 to 29, 2011. The same venue hosted the most important international metallurgical trade fairs for metallurgy of iron and steel, new casting and thermochemical processes METEC, GIFA, THERMOPROCESS and NEWCAST. The previous European metallurgical conferences were organized by GDMB in Friedrichshafen (2001), Hanover (2003), Leipzig (2005), Duesseldorf (2007), Innsbruck (2009). The GDMB is a non-profit organization situated in Clausthal in Germany, which is related to combining science with the practical experience in metallurgy, mining, materials engineering, mineral processing, recycling and refining of metals, and manufacturing of semi- and finishing products. The European Metallurgical conference EMC is one of the most known conferences worldwide in the field of non-ferrous metallurgy and is attended regularly by the decision makers from the industry and universities. The scientific program contained 6 plenary lectures and more than 160 presentations from 40 countries in 5 parallel series. An extensive poster exhibition was held, during which the authors had an opportunity to introduce their posters to the entire plenum as a part of a brief presentation. The best poster from the Montan-University in Leoben, Austria, was awarded the € 500 'Poster Award EMC 2011'. Not only were the most important European countries represented here, more than one third of the lecturers were from the non-European countries (Canada, Japan, China, USA, South Africa, Australia). The origin of the participants reflects the aim of the organizers: to make this conference a worldwide platform for the scientific exchange of experience and information. More than 400 participants from all over the world participated at this conference. The scientific presentations of the conference are presented in five Proceedings: Vol. 1: Copper, General Pyrometallurgy, Vessel Integrity, Process Gas Treatment; Vol. 2: Lead and Zinc, Process Control, Process Modeling, Vol. 3: Light metals, General Hydrometallurgy, Precious Metals; Vol. 4: Process Metallurgy, Recycling, Waste Treatment and Prevention, Vol 5: Sustainable technologies, Sustainable of non-ferrous metals production, waste effluents Treatment and Biohydrometallurgical application. The plenary lectures will be published in the scientific journal 'World of Metallurgy - ERZMETALL', which is published by the GDMB.