Vojnotehnicki glasnik / Military Technical Courier

Number 1(50), 2002

5-13
Statistical models of spare part requirement prediction [ 2 ]

Authors: Mišković Vasilije, Borović Siniša

Abstract

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Number of views: 288

Spare part supply is one of the key parts of effective system maintenance A successful spare part providing depends on the possibility to predict requirements. There are several kinds of production models and the statistical one is one of them. In this article we present two statistical models. One model is applicable if there is no data about spare part requirements in the past. Another model is used if such data exists. The first model was experimentally verified and, considering the experimental results, wecan conclude that the proposed model gives very good results.

14-27
Application of the MUSIC method for direction of arrival estimation using the ADCOCK antenna arrays

Authors: Erić Miljko M., Dukić Miroslav L., Pokrajac Ivan

Abstract

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Number of views: 306

The MUSIC based Direction of Arrival estimation using the ADCOCK antenna arrays is considered. Starting from signal model formulation, the cost function of the MUSIC algorithm and the ambiguity functions for the ADCOCK antenna array have been formulated. Some simulation results and some preliminary results of the verification in practice are presented.

28-35
Investigation of the influence of the mass average ratio of nitrogen in nitrocellulose and the particle size on burning rates of double base propellants [ 1 ]

Authors: Maslak Panto, Tot Lajoš

Abstract

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Number of views: 303

The investigation described in this paper concerns the experimental phenomenological study of catalytic activity of ballistic catalysts: basic lead-stearate, calcium carbonate, cobalt trioxide and carbon black for different mass portions of nitrogen in nitrocellulose as components of a double base propellant, as well as the influence of the dimensions of ballistic catalyst particles on the double base propellants burning rate. The catalyst activity ratio in used as a measure of catalyst activity, and it represents the ratio of the burning rate of a double base propellant with catalysts referent model to the burning rate of a double base propellant without ballistic catalysts referent model. The paper gives the experimental results of the double base propellant burning rate. The appropriate models of the burning rate dependence on the pressure within the rocket motor are derived.

36-41
Logistic information system management

Authors: Stojanović Miroslav, Bulajić Đuro, Rakić Vladimir

Abstract

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Number of views: 276

We presented the results of the realization of the logistic information system. While fulfilling this task we connected computers physically and succored logical functioning of the system on three levels (command management and execution level). We designed software, using modern software development tools and worked on the education of professional military officials for PC using and basic maintenance of computer equipment.

42-49
Study of the effects of activated carbon oxidation with sulphuric acid and impregnation with copper sulphate on the protection capacity of gas filters against ammonia

Authors: Ilić Sretko, Nikolić Dragan

Abstract

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Number of views: 271

The objective of this paper has been the study of the possibility to enhance the properties of activated carbon (AC) for using it in respiratory protective devices for ammonia removal from the air. The commercial AC samples were oxidized with different amounts of 10% and 15% sulphuric acid solutions. The acid treated AC samples were the loaded with copper sulphate with twofold impregnation by the incipient wetness method. The impregnated AC was tested in a packed bed in the gas filter with a diameter of 105 mm and a bed depth ranging from 29 mm to 41 mm under the following test conditions inlet concentration of ammonia was 3,5 mg/dm3, flow rate of 30 dm3/min at 70% relative humidity and ambient temperature. The breakthrough was detected qualitatively by the phenolphtalein indicator paper. The new impregnated AC reached the breaktrough time of 108 min for a 29 mm bed depth, and 160 min for a bed depth of 41 mm.

50-60
Whole body vibration on helicopter pilot seat for two types of helicopters

Authors: Živković Dejan, Basarić Gradimir, Jovelić Stojan

Abstract

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Number of views: 275

The aim of the work was to measure the whole body vibration on helicopter pilot seats in two types of helicopters with jet engines and to accomplish the third octave analysis of whole body vibration acceleration in all three axes. The results of measurement on the first type of helicopters showed that the highest acceleration levels were in third octave band with the mid frequency of 16 Hz. The highest whole body vibration acceleration values were for the following regimes: the regime of levitation and the regime of horizontal flight with a speed of 250 km/h. The permissible exposure time periods for these acceleration levels were around 5 hours. The results of measurement on the second type of helicopters showed that the highest acceleration levels were in the third octave band with the mid frequency of 6,3 Hz. The highest whole body vibration acceleration values were for the following regimes: the regime of turning point and the regime of horizontal flight with a speed of 200 km/h. The permissible exposure time periods for these acceleration levels were around 3 hours. The acceleration levels in X or Y axes for both types of helicopters, in all regimes and all third octave bands, were very far below from the exposure levels for 24 hours. Since the pilots 'continuous exposure in the investigated regimes of flights is below these mentioned time periods, we can conclude that the whole body vibration levels do not have significant effects on the pilots' working ability.

61-72
Adaptive digital filters

Authors: Petković Dragan

Abstract

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Number of views: 290

The paper describes the basis of adaptive filter functioning. The first considerations deal with the mathematical processing of discrete signals and the Z-transform in adaptive filters. The Wieners filter processing problem was exposed. The Correlation Canceler Loop (CCL) was presented as well as the Widrow-Hoffs adaptive Least Mean Squares (LMS) step-by-step procedure. The convergence rate of adaptive filters was considered as well. The CCL simulations were obtained pointing out the convergence rate.

73-81
Identifying and eliminating deformations of geographic maps [ 2 ]

Authors: Borisov Mirko

Abstract

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Number of views: 267

The article deals with the analysis of deformations of geographic map contents and the procedure of eliminating deformations. Geographic maps are used for visualizing and studying geospatial data and for identifying metric features. For that reason the accuracy analyses are very important as well as the elimination of all possible deformations of the maps.

82-89
Project risk management [ 1 ]

Authors: Stojković Dejan

Abstract

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Number of views: 334

The risk management is a specific process in the application of the complete project management concept. The project risk management consists of risk identification, analysis and estimation of risk, planing of the response to the risk and control of the risk. In this paper the complete project risk management approach is presented.

90-100
Savremeni avionski radari zapadnih zemalja

Authors: Pokorni Slavko

Abstract

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Number of views: 334

The article does not contain abstract.